"NOVEL EFFLUX PUMP INHIBITORS"

Field of the invention

The present invention relates to the field of chemotherapeutics, particularly use of novel synthetic aromatic amides for potentiating the bio-efficacy of specific drugs. The invention particularly relates to the preparation and use of synthetic analogues of aromatic amides, useful in potentiating bio-efficacy of anti-infective drugs. The invention more particularly relates to aromatic substituted acrylic acid amide of general formula 1 including its analogues or and salts thereof

Formula-1

Wherein n~ 1 or 2, dotted lines indicates the single or double bond, wherein n=l R ₇ - H wherein n=2 R ₇ = normal or branched chain Cl to ClO alkyl group, phenyl, benzyl radical at 4-position and R ₇ =H at C-2 position, wherein R is selected from a group consisting of halogen, hydrogen, alkyl (Cl to ClO) or aryl or benzyl (unsubstituted and substituted); R1,R2,R3,R4 is hydrogen, nitro, halogen, hydroxy, alkyloxy, alkenyloxy* aryloxy, substituted pyranyl radical, unsubstituted pyranyl radical or R ₁ , R ₄ represents hydrogen group and R ₂₁ R ₃ represent hydrogen ,alkoxyl(Cl-C10), alkenoxyl groups (Cl-ClO), aryloxyl, substituted aryloxyl groups or Ri, R ₄ represents hydrogen group and R2+R3 together represent 1,3-dioxol , 1,4-dioxol; R ₃ - represents hydrogen atom or normal or branched chain C ₁ to C ₁₀ alkyl group or phenyl or benzyl radical and R ₆ represents hydrogen atom or normal or branched chain Ci to Cm alkyl group or phenyl or benzyl radical; where NR ₅ R ₆ together (R ₅ +R ₆ ) represent heterocyclic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N- methylpiperazinyl, oxazolyl, N-methylpiperazinyl, pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and the like and optionally converting them to their salts by method known in the art of synthesis.

The novel amide when administered in combination with an anti-infective drag potentiates the bioactivity of the drug thereby requiring lower doses and/or decreased frequency of dosing while maintaining the therapeutic efficacy of standard doses of such drugs. The synthetic molecules of this invention are all novel, as they have not been reported 5 earlier in the literature. These novel molecules possess specific properties of potentiating the bio-efficacy of specific drugs particularly they are useful in combination with anti-infective drugs which besides reducing their effective dosages are also associated with lesser side effects. The molecules along with the pharmaceutical products/combinations possessing the properties disclosed in the present invention are novel and not known in literature or prior LO art.

Background of the invention

For preventive or therapeutic treatment of infectious diseases caused by micro-organisms, various antibacterial agents have so far been developed, and drags such as β -lactam

[5 antibiotics (penicillins, cephems, monobactams, carbapenems, and penems), aminoglycosides, quinolones, macrolides, tetracyclines, rifamycins, chloramphenicols, and phosphomycins have been practically used. However, with the increase of clinically used amount of antibacterial agents, remarkable numbers of resistant bacterial strains to these antibacterial agents have emerged, which becomes a serious problem in the treatment of

>0 infectious diseases.

There are three proven targets for the main antibacterial drags: (1) bacterial cell-wall biosynthesis; (2) bacterial protein synthesis; and (3) bacterial DNA replication and repair. There are number of mechanisms through which the micro-organisms resistance against these therapeutic agents. These mechanisms include target overproduction or modification,

J5 permeability barriers (reduced uptake or active efflux), enzymatic inactivation, and sequestration.

One of the most frequently employed resistance strategies in both pro-karyotes and euk, yotes is the transmembrane efflux pump proteins, which are involved in the extrusion of toxic substrates (including virtually all classes of clinically relevant antibiotics) from

SO within cells into the external environment. These proteins are found in both gram-positive and gram-negative bacteria as well as in eukaryotic organisms (F. Van Bambeke, E. Balzi,

?

P.M. Tulkens, Biochem. Pharmacol. 60 (2000) 457-470 Pumps may be specific for one substrate or may transport a range of structurally dissimilar compounds (including antibiotics of multiple classes); such pumps can be associated with multiple drug resistance (MDR). In the prokaryotic kingdom, there are five major families of efflux transporter (O. 5 lomόvskaya, M.. S. Warren. A; Lee, J. Galazzo, R ₁ fronko, M. Lee, J, Blais, D. Cho, S. Chamberland, T.ranau, R. Leger, S. Hecker, W. Watldns, K. oshino, H. ishida, V. J. Lee., Antimicrob. Agents and Chemother. 2001, 45: 105-116. MF (major facilitator), MATE (multidrug and toxic efflux), RND (resistance-nodulation-division), SMR (small multidrug resistance) and ABC (ATP binding cassette). All these systems utilize the proton motive

10 force as an energy source (LT. Paulsen, Microbiological Reviews, 1996, 60: 575-608 apart from the ABC family, which utilizes ATP hydrolysis to drive the export of substrates. In gram-positive bacteria, MDR is mainly conferred by MFS efflux systems, the most studied pumps being Nor A of S. aureus (A. A. Neyfakh, C.M.Borsch, G.W.Kaatz Antimicrob. Agents and Chemotherapy, 1993, 37: 128-129) and its homologues in B.

15 subtilis, Bmr and Bit (A. A. Neyfakh, Antimicrob. Agents and Chemotherapy, 1992, 484- 485). For gram-negative bacteria, RND efflux systems are major contributors to resistance: AcrAB-TolC and MexABOprM are involved in intrinsic resistance of E. coli (M. C. Sulavik. C. Houseweart, C.cramer, N. Jiwai, N. Murgolo, J. Greene, B. Didomenico, K. J. Shaw, G. H. Miller, R. Hare, G. Shinier Antimicrob. Agents and Chemotherapy, 2001, 45:

10 1126-1136) and P. aeruginosa (X. Li, N.Nikaido,L.Poole Antimicrob. Agents and Chemotherapy, 1995, 35: 1948-), respectively. One strategy to target these microbial efflux pumps is to find inhibitors of these efflux pumps and, in particular of bacterial and fungal efflux pumps. Recently, we have demonstrated, the preparation and the application of newer class of

.5 synthetic molecules as potentiators of bioefficacy of antiinfectives (S. Koul, J.L. Koul, S. C. Taneja, P. Gupta, LA. Khan, Z.M. Mirza, A. Kumar, R.K. Johri, M. Pandita, A. Khosa ^' , A.K. Tikoo, S.C. Sharma, V. Verma, and G.N. Qazi. U.S. PGPUB-0004645), where in the inhibitors disclosed are 4-alkyl-5-substituted phenyl 2£,4.£-pentadienoicacid amides and its tetra hydro analogies which is unlike the efflux pump inhibitor compounds of the present

$0 invention. It may be said here that in the above mentioned U.S. patent 20070004645 the potentiation of the drugs like ciprofloxacin and mupirocin in combination with most potent

compounds like 5-(3,4-methylenedioxyphenyl)-4-ethyl-2E,4E-pentadienoic acid piperidide & 5-(3,4-dimethoxyphenyl)-4-ethyl-2E,4E-pentadienoic acid piperidide) showed up to eight fold reduction in the MIC of the said drugs. Whereas, the present invention discloses up to sixteen fold reduction in the MIC of the above said drugs (as shown in the examples 69a to 5 75 and tables 1 to 5 of the present invention).

Objects of the invention

The main object of the present invention is to provide the novel 3-(l-substituted-3,4- dihydro-naphth-2-yl)-acrylic acid amide, its tetra hydro derivatives of general formula Ia, 10 laa and 5-(l-substituted-3,4-dihydronaphth-2-yl)-4-alkyl-2E,4E-penta dienoic acid amides its tetrahydro derivatives of structure formulae Ib, lba its analogues and /or their salts thereof.

Another object of the invention is to provide the novel aromatic substituted pentadienoic acid amide, which may be useful as potentiators of the bioefficacy of the drugs. 15 Yet another object of the invention is to provide the process for the preparation of the novel aromatic amides.

Still another objective of the invention is to provide the compounds of formula 1, which are not toxic.

Further object of the invention is to provide the pharmaceutical composition using effective ZO amount of one or more compound of formula Ia including its geometrical isomers, its analogues or and salts thereof as stated above along with the anti-infective drug and optionally along with a carrier or diluent or pharmaceutically acceptable exciepient.

Another object of the invention is to provide the pharmaceutical composition, which is useful for the treatment of the infections caused by bacteria. .5 Further object of the invention is to provide the pharmaceutical composition which is used in the reduction in the dose requirement of anti-infectives.

Summary of the invention

The present invention provides a new class of bacterial efflux pump inhibitors(EPIs) (not »0 reported in the literature) for therapeutic use when co-administered with antiinfectives (antibiotics).The EPIs as per the present invention belongs to the general formula 1

Formula-1

1a 1aa

1 b 1ba wherein the compounds falling under the general formula laa,lab,lba and laa belong to 3-

(l-substituted-3,4-dihydro-naphth-2-yl)-acrylic acid amide, its tetra hydro derivatives (general formula Ia, . laa) and 5-(l-substituted-3,4-dihydronaphth-2-yl)-4-alkyl-2E,4E- pentadienoic acid amides its tetrahydro derivatives (general formulae Ib, lba) its analogues and /or their salts thereof. Strains of Staphylococcus aureus 1199 and its mutant Nor A over expressing Staphylococcus aureus 1199B of the genus Gram +ve bacteria known for its resistance to a host of antibiotics (including Ciprofloxacin) when treated with a formulation comprising of antibiotic ciprofloxacin and an EPI (selected from the compounds of the formula 1) in a given definite ratio by potentiation of the drug activity which is because of the inhibition of the efflux pump present in the bacteria. This is evidenced by the experiments shown in the present invention using ethidium bromide (EtBr) which is the substrate of efflux' pump and is thrown out as evidenced by the fast loss of fluorescence of

EtBr whereas in presence EPI there is retention of the fluorescence of EtBr and no fluorescence depletion is observed.

The present invention describes a new class of bacterial efflux pump inhibitors (EPIs) for therapeutic use when given in combination with antibiotics. The EPIs as per the present invention are selected from the general formula 1 which contains compounds that belong to 3-(l-substituted-3,4-dihydro-naphth-2-yl)-acrylic acid amide, its tetra hydro derivatives (general formula Ia, laa) and 5-(l-substituted-3,4-dihydronaphth-2-yl)-4-alkyl-2E,4E- pentadienoic acid amides its tetrahydro derivatives (general formulae Ib, lba) its analogues and /or their salts thereof. A formulation comprising of an antibiotic such as ciprofloxacin is co-administered with an EPI selected from the above mentioned class of compounds and tested against drug resistance bacterial strains such as Staphyllococcus aureus 1199 and its mutant Nor A over expressing Staphyllococcus aureus 1199B (Gram +ve bacteria known for its resistance to aJiost of antibiotics including Ciprofloxacin,mupirocin ). The drug potency is restored due to the inhibition of the bacterial efflux pump as evidenced by the experiments using ethidium bromide (EtBr) where the EPI inhibits the fast loss of fluorescence of EtBr which in absence of EPI is depleted fast.

In the present invention, preparation and application of a new class of bacterial efflux pump inhibitors (EPIs) for therapeutic use is described when given in combination with antibiotics. The EPIs as per the present invention are selected from the general formula 1 which contains compounds that belong to 3-(l-substituted-3,4-dihydro-naphth-2-yl)-acrylic acid amide, its tetra hydro derivatives (general formula Ia, laa) and 5-(l-substituted-3,4- dihydronaphth-2-yl)-4-alkyl-2£,4ii-pentadienoic acid amides its tetrahydro derivatives (general formulae Ib, lba) its analogues and /or their salts thereof. A formulation comprising of an antibiotic such as ciprofloxacin is co-administered with an EPI selected from the above mentioned class of compounds and tested against drug resistance bacterial strains such as Staphyllococcus aureus 1199 and its mutant Nor A overexpressing Staphyllococcus aureus 1199B (Gram +ve bacteria known for its resistance to a host of antibiotics including Ciprofloxacin,mupirocin ). The drug potency is restored due to the inhibition of the bacterial efflux pump as evidenced by the experiments using ethidium bromide (EtBr) where the EPI inhibits the fast loss of fluorescence of EtBr which in absence of EPI is depleted fast as shown in Figure- IA and Figure- IB

Brief description of the drawings

Figure-IA Accumulation of ethidium bromide in wild type and mutant strain, CIPr-I and effect of compound of formula Ia corresponds to compound 3-(l-chloro-3,4-dihydronapth- 2-yl)-acrylic acid N ₅ N-diisopropylamide at 25 μg/ml.

In the figure-IA, the compound of formula I was added after 30 min (as indicated by the arrow in the figure) of the start of the experiment. This addition resulted in the increased accumulation of ethidium bromide (due to the inhibition of the efflux pump) in the wild and mutant strains as indicated by the increase in the fluorescence intensity.

Figure-IB Efflux of ethidium bromide in wild type and mutant strain. ClP ^r -l and effect of compound of formula Ia corresponds to compound 3-(l-chloro-3,4-dihydronapth-2-yl)- acrylic acid N,N-diisopropylamide at 25 μg/ml.

Figure-IB depicts the inhibition of efflux of ethidium bromide from the wild and mutant strain of S. aureus when pretreated with the compound of formula Ia, resulting in no loss of fluorescence compared to controls where the compound of formula I is not present, which leads to rapid decrease in the fluorescence.

Description of the invention

Accordingly the present invention provides a substituted aromatic amides of general formula Ia, Ib, laa, lba and salts thereof as potentiators of bioefficacy of anti-infective drugs when used in combination with anti-infective drugs in the form of a pharmaceutical composition.

Ia, Ib, laa and lba

Wherein n= 1 or 2, dotted lines indicates the single or double bond, wherein n=l R7 = H wherein n=2 R7 = normal or branched chain Cl to ClO alkyl group, phenyl, benzyl radical

at 4-position and R7=H at C-2 position, wherein R is selected from a group consisting of halogen, hydrogen, alkyl (Cl to ClO) or aryl or benzyl (imsubstituted and substituted); R1,R2 ₅ R3,R4 is hydrogen, nitro, halogen, hydroxy, alkyloxy, alkenyloxy, aryloxy, substituted pyranyl radical, unsubstituted pyranyl radical or Rl, R4 represents hydrogen group and R2, R3 (R2=R3) represent hydrogen , alkoxyl (Cl-ClO) , alkenoxyl groups (Cl- ClO) , aroyloxyl or substituted aroyloxyl groups or Rl, R4 represents hydrogen group and R2 + R3 together represent 1,3-dioxol or 1,4-dioxol;

R ₅ represents hydrogen atom or normal or branched chain Ci to Cio alkyl group or phenyl or benzyl radical and R ₆ represents hydrogen atom or normal or branched chain C ₁ to C ₁₀ alkyl group or phenyl or benzyl radical; where NR ₅ R ₆ together (R ₅ H-R ₆ ) represent heterocyclic amine radical ^" such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N- methylpiperazinyl, oxazolyl, N-methylpiperazinyl, pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and the like and optionally converting them to their salts by method icnown in the art of synthesis. The structural formula of compound Ia, Ib, laa and lba, represented as follows :

Ia

laa

Formula-la and laa, wherein R is selected from a group consisting of halogen, hydrogen, alkyl (Cl to ClO), aryl, benzyl (unsubstituted and substituted);

R1,R2,R3,R4 is hydrogen, nitro, halogen , hydroxy, alkyloxy, alkenyloxy, aryloxy, substituted pyranyl radical ,unsubstituted pyranyl radical or Rl , R4 represents hydrogen group and R2, R3( R2=R3) represent hydrogen , alkoxyl (Cl-ClO) or alkenoxyl groups (Cl-

ClO) also aryloxyl or substituted aryloxyl groups or Rl, R4 represents hydrogen and R2+R3 together represent 1 ,3-dioxol or 1 ,4-dioxol,;

R ₅ represents hydrogen atom or normal or branched chain Ci to C ₁₀ alkyl group or phenyl or benzyl radical and R ₆ represents hydrogen atom or normal or branched chain C ₁ to Cjo alkyl group or phenyl or benzyl radical; where NR ₅ R ₆ together (R ₃ -+R ₆ ) represent heterocyclic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N- methylpiperazinyl, oxazolyl, N-methylpiperazinyl, pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and the like.

Ib

lba

Formula-lb and lba, wherein R is selected from a group consisting of halogen, hydrogen, alkyl (Cl to ClO), aryl , benzyl (unsubstituted and substituted);

R1,R2,R3,R4 is hydrogen, nitro, halogen, hydroxy, alkyloxy, alkenyloxy, aryloxy, substituted pyranyl radical ,unsubstituted pyranyl radical or Rl, R4 represents hydrogen group and R2, R3(R2=R3) represent hydrogen, alkoxyl(Cl to ClO), alkenoxyl groups (Cl- ClO) ₅ aryloxyl, substituted aryloxyl groups or Rl, R4 represents hydrogen group and R2+R3 together, represents 1 ,3-dioxol or 1 ,4-dioxol,; R ₅ represents hydrogen atom or normal or branched chain Ci to C] ₀ alkyl group or phenyl or benzyl radical and R ₆ represents hydrogen atom or normal or branched chain Ci to Cio alkyl group or phenyl or benzyl radical; where NR ₅ R ₆ together (R ₅ +R ₆ ) represent heterocyclic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N-methylpiperazinyl, oxazolyl, N-methylpiperazinyl _. ,

pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and the like, wherein R7 represents normal or branched chain Cl to ClO alkyl group.

In an embodiment of the invention wherein the salt is pharmaceutically acceptable selected from hydrochloride, acetate, succinate, maleate.

Accordingly the present invention provides a process for the preparation of substituted aromatic acid amides of general formula Ia, laa, Ib and lba as stated above, the method of preparation comprising;

(i) subjecting aldehyde compound of formula 2,

Formula 2 Formula 3 wherein R is selected from a group consisting of halogen, hydrogen, alkyl (Ci to Ci ₀ ) or aryl or benzyl (unsubstituted and substituted); Ri,R2,R ₃ ,R ₄ is hydrogen, nitro, halogen, hydroxy, alkyloxy, alkenyloxy, substituted pyranyl radical, unsubstituted pyi'anyl radical or Ri ₁ R ₄ represents hydrogen group and R ₂₅ R ₃ (R2=R3) represent hydrogen, alkoxyl ^' (C _I -C _I0 ), alkenoxyl groups (Ci-Cio), aryloxyl, substituted aryloxyl groups or Ri ₁ R ₄ represents hydrogen group and R2+R3 together represent 1,3-dioxol or 1,4-dioxol to Wittig reaction (Wittig reagent prepared from triphenylphosphine and ethyl bromoacetate/ ethylchloroacetate in equimolar mixture in presence of a strong base such as sodium hydride, sodium methoxide and the like at temperature 5-80 ⁰ C for 1 to 24 hrs in an ethereal medium such as diethyl ether, dimethoxyethane and the like benzene/toluene or dimethylformamide) and subsequent saponification of the Wittig reaction product to get compound of the formula 3, (ii) alternately allowing aldehyde of the formula 2 to react with malonic acid in presence of a base like piperdine and pyridine, contents stirred at temperature 25-40 ⁰ C for 24-30 hours followed by subsequent decarboxylation carried out by heating at 80-90 ⁰ C, acidification of the reaction mixture by dilute HCl, or H ₂ SO ₄ or the like, extraction of the contents, concentration of the organic layer, to get the compound of formula 3,

(iii) treating the compound of formula 3 with thionylchloride and subsequent reaction of the acid chloride thus prepared with an appropriate amine to get the compound of formula Ia by conventional method wherein RiR ₂ R ₃ R ₄ is hydrogen, nitro, halogen , hydroxy, alkyloxy, alkenyloxy, substituted pyranyl radical,un-substituted pyranyl radical or R _1, R ₄ -represents hydrogen group and R _{2 ,} R ₃ (R2=R3) represent hydrogen , alkoxyl (Ci-C ₁₀ ) or alkenoxyl groups (Ci-Cio) , aryloxyl , substituted aryloxyl groups or Ri _; R ₄ represents hydrogen group and R2 + R3 together represent 1,3-dioxol or 1,4-dioxol, ;R ₅ represents hydrogen atom or normal or branched chain C ₁ to Ci ₀ alkyl group or phenyl or benzyl radical and R ₆ represents hydrogen atom or normal or branched chain C ₁ to Ci ₀ alkyl group or phenyl or benzyl radical; where NR ₅ R ₆ together (R ₅ +R ₆ ) represent heterocyclic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N-methylpiperazinyl, oxazolyl, N- methylpiperazinyl, pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and optionally converting them to their salts by known method by reacting with an acidic compounds such as hydrochloric acid, acetic acid, tartaric acid,

Formula 1 a

(iv) converting the compound of formula Ia to its tetrahydro derivative by hydrogenation in presence of Pd/charcoal in polar solvent such as methanol or ethanol at ambient temperature >0 and at 1-3 atmospheric pressure to obtain corresponding tetrahydro derivative of general formula laa,

Formula laa

(v) alternately, hydrogenation of compounds of the formula 3 with Pd/charcoal/ solvents5 such as methanol, ethanol, ethylacetate and at 1-3 atmospheric pressure and treatment of the

tetrahydro derivative with thionyl chloride and followed by treatment of the acid chloride with appropriate amine afforded compound of the formula Iaa wherein R,R1,R2,R3,R4,R5,R6 are radicals/groups as described above for the compound of the formula Ia,

(vi) For the preparation of compound of the formula Ib the method of preparation comprises of reacting compound of the formula 2 with Grignard reagent prepared from appropriate alkyl halide (represented by R ₇ X, chosen from Cl-ClO normal or branched alkylhalide, substituted or unsubstituted benzyl or aryl halides) and Mg metal with constant stirring at ambient temperature in an anhydrous ether/THF solvent to produce compound of the formula 4 wherein R ₁₁ R ₂ R ₃₁ R ₄ is hydrogen, nitro, halogen, hydroxy, alkyloxy, alkenyloxy, substituted pyranyl radical, unsubstituted pyranyl radical or R ₁ ; R ₄ represents hydrogen group and R ₂ ,R ₃ (R2=R3) represent hydrogen atoms or alkoxyl(Cl to ClO) or alkenoxyl groups (C]-Cio), aroyloxyl, substituted aroyloxyl groups or Ri, R ₄ represents hydrogen group and R2+R3 together represent 1,3-dioxol or 1,4-dioxol and R7 is Cl-ClO normal or branched alkylhalide, substituted or unsubstituted benzyl or aryl halides,

Formula Ib

(vii) The compounds of formula -4 treated with Vilsmeier reagent comprising of dimethylformamide and phosphorus oxychloride/phosphorus oxybromide or phosphorus tribromide mixture at 0-50 ⁰ C preferably at 0-10 ⁰ C for 5-50 hrs. Preferably for 5-12 hrs, followed by dilution of contents with ice cold water, bringing the pH to 7 by neutralisation with dilute alkali solution to produce compound of formula 5 wherein R1,R2,R3,R4 and R7 are radicals or substituents as described in for compounds of the formula 4,

Formula 5

(viii) condensation of the compounds of the formula 5 with an ylide (Wittig reagent, prepared from triphenylphosphine and ethyl bromoacetate/ ethylchloroacetate) in equimolar mixture in presence of a strong base such as sodium hydride, sodium methoxide and the like at a temperature ranging between 5-80 ⁰ C for a period ranging between 1 to 24 hrs in an ethereal medium such as diethyl ether, dimethoxyethane and the like, or benzene/toluene or dimethylformamide followed by direct saponification of Wittig reaction product furnished compounds of the formula 6 wherein R ₁₁ R ₂ R ₃₁ R ₄ is hydrogen, nitro, halogen, hydroxy, alkyloxy, allcenyϊoxy, substituted pyranyl radical, unsubstituted pyranyl radical or Ri ₁ R ₄ represents hydrogen group and R ₂ ,R ₃ represent hydrogen, alkoxyl (C ₁ -Ci ₀ ), alkenoxyl groups (Ci-Cio), aryloxyl, substituted aryloxyl groups or R) ₁ R ₄ represents hydrogen group and R1+R2 together represent 1,3-dioxol or 1,4-dioxol; and R7 is Cl-ClO normal or branched alkylhalide, substituted or unsubstituted benzyl or aryl radical,

Formula 6 (ix) treating the compound of the general formula 6 with thionyl chloride in presence of a base such as pyridine followed by treatment of the acid chloride with an appropriate base afforded compounds of the formula Ib wherein R is selected from a group consisting of halogen, hydrogen, alkyl (Cl to ClO) or aryl or benzyl (unsubstituted and substituted); R1,R2,R3,R4 is hydrogen, nitro, halogen, hydroxy, alkyloxy, alkenyloxy, aryloxy, sxibstituted pyranyl radical, unsubstituted pyranyl radical or Rl, R4 represents hydrogen group and R2, R3 represent hydrogen, alkoxyl (Cl-ClO), alkenoxyl groups (Cl-ClO) ₁ , aryloxyl, substituted aryloxyl groups or Rl, R4 represents hydrogen group and R2+R3 together represents 1,3-dioxol or 1,4-dioxol; R ₅ represents hydrogen atom or normal or branched chain C ₁ to C ₁₀ alkyl group or phenyl or benzyl radical and R ₆ represents hydrogen atom or normal or branched chain Ci to Ci ₀ alkyl group or phenyl or benzyl radical; where NR ₅ R ₆ together (R ₅ +R ₅ ) represent heterocyclic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N-methylpiperazinyl, oxazolyl, N-methylpiperazinyl, pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and the like, wherein R7 represents normal or

branched chain Cl to ClO alkyl group,

Formula Ib

(x) converting the compound of formula Ib to its tetra hydro derivative by hydro genation in presence of Pd/charcoal in polar solvent such as methanol or ethanol or ethyl acetate at ambient temperature and at a pressure ranging between 1-3 atmosphere to obtain compound of formula lba.

Formula lba

(xi) alternately, hydrogenation of compounds of the formula 6 with Pd/charcoal/ solvents such as methanol, ethanol, ethyl acetate and at a pressure ranging between 1-3 atmosphere and subsequent treatment of the tetrahydro derivative with thionyl chloride followed by treatment of the acid chloride thus obtained with appropriate amine afforded compound of the formula lba wherein R,R1,R2,R3,R4,R5,R6,R7 are radicals/groups as described above for the compound of the formula Ib.

In an embodiment of the invention wherein the use of compound of formula 1 that include compounds of the formula la,laa,lb and lba as potentiator of bioefiϊcacy of anti-infective drugs.

In another embodiment of the invention wherein the process further comprises converting the compound of formula Ia,laa4b and lba into a salt.

Accordingly, the present invention provides a pharmaceutical composition comprising an effective amount of one or more compound of formula la,laa,lb and lba its analogues or /and salts thereof as stated above along with the anti-infective drug and optionally along with a carrier or diluent or pharmaceutically acceptable exciepient.

In an embodiment of the invention the amount of compound of formula 1 may vary from 0.1 to 50% by weight of the composition with respect to the drug.

In another embodiment of the invention wherein the composition is useful as an anti - microbial agent.

In yet another embodiment of the invention wherein the MIC value of composition is reduced more than 32 times of the anti- infective drugs when used alone. In an another embodiment of the invention wherein the ED50 of anti-infective drug reduced to about 1/4 when used in combination with the compound of formula Ia, laa, Ib and lba.

In still another embodiment of the invention wherein the dose of anti-infective drugs is reduced about ¹ A when used in combination with compounds of formula la,laa,lb and lba.

In further embodiment of the invention wherein the anti-infectives are selected from groups comprising of penicillins (including semi-synthetic), cephalosporins, aminoglycosides, glycopeptides, fluroquinolones, macrolides, tetracyclines other antibiotic groups such as mupirocin and framycetin, first and second line anti-TB drugs, anti-leprosy ^' drugs, oxazolidinones.

In an embodiment of the invention wherein the composition is effective against micro- organisms selected from gram positive bacteria and gram negative bacteria, that include

Staphylococcus species, Bacillus species. Pseiidomonas species, E coli and Salmonella species as well as against micro-organisms such as Mycobacterium species.

In another embodiment of the invention wherein composition is effective against growth of micro-organisms that include anti-infective resistant strains such as MRSA. In a further embodiment of the invention wherein composition is effective when tested for curing of mice, guinea pig or rabbit models infected with micro-organisms from the gram positive group of bacteria and gram negative group of bacteria such as Staphylococcus species,

Bacillus species., Pseiidomonas species, E coli, Salmonella species besides being effective against microorganisms such as Mycobacterium species. In an embodiment of the invention wherein the said composition along with excipient or pharmaceutical vehicle such as lactose, corn starch, polyethylene glycols and the like may be administered through oral route.

In an embodiment of the invention wherein the said composition along with excipient or pharmaceutical vehicle such as castor oil, olive oil and the like may be administered through systemic route.

In an embodiment of the invention wherein the said composition along with excipient or

pharmaceutical vehicle such as polyethylene glycols, bees wax, paraffin wax, emulsifying agents and the like may be applied topically.

A method for inhibiting a bacterial cell that employs an efflux pump resistance mechanism, comprising contacting the cell with a pharmaceutical composition comprising of an antibacterial agent and a compound of formula la,laa,lb,lba and optionally an excipient or pharmaceutical vehicle.

In an embodiment of the present invention wherein the bacterial cell is selected from gram positive bacteria such as Staphylococcus species and Bacillus species.

In one more embodiment of the invention wherein the bacterial cell is selected from gram negative bacteria such as Pseudomonas species, E coli and Salmonella species.

In a further embodiment of the invention wherein the bacterial cell is selected from mycobacterial species.

A method of treating infections comprising administrating to a subject in need of such treatment a therapeutically effective amount of compound of formula Ia, laa, Ib, lba, its analogues or/ and salts thereof as claimed in claim 1 along with the anti-infective drug and optionally along with a carrier or diluent or pharmaceutically acceptable exciepient.

In one of the embodiment of the invention wherein the infection caused by a bacteria that employs an efflux pump resistance as one of the ways of resistance, comprising administering to a patient in need thereof a therapeutically effective amount of an antibacterial agent and a compound of formula Ia, laa, Ib and lba.

The present invention deals with such combinations comprising 3-(l-substituted-3,4- dihydro-naphth-2-yl)-acrylic acid amide of structural formula Ia, including its related tetralin derivatives of structural formulae laa and 5-(l-substituted-3,4-dihydronaphth-2-yl)- 4-alkyl-2E,4E-pentadienoic acid amide of formula Ib including its related tetralin derivatives of structure formulae lba where R ₁ to R ₇ are as described above and as a representative example of formula 1 where R=Cl, Ri=R ₂ =R ₃ =R ₄ =H and R ₅ +R ₆ =isobutylamine (example-5) and N,N-diisopropylamine (example-8), displayed the properties of potentiation/synergism in in vitro screening when combined with various anti- infective agents using bacteria, viruses and yeast. These combinations were also efficacious when tested in in vivo using mice and guinea pig models infected with microorganisms (example 69d-f and 73 a) and displayed the properties of potentiation/synergism when

combined with various anti-infective agents in vitro using bacteria, viruses and yeast. The present invention is aimed to circumvent such problems and use of the products of the present invention offer a low dose regimen that produces enhanced therapeutic action comparable to that of standard dose of a drug alone. The compounds of the present invention are neither reported in the chemical literature nor have been used for the purpose of potentiating the bio-efficacy of the drugs particularly anti- infective drugs such as described in the present invention. The synthesis of the novel compounds have been accomplished through the combination of various chemical steps known in the art of synthesis though not for the purpose of synthesising the novel compounds of formula Ia, laa, Ib and lba as described above.

The aromatic amide of formula 1 i.e. 3-(l-substituted-3,4-dihydronaphth-2-yl)-acrylic acid amide, including its related tetralin derivatives of structural formulae Ia and 5-(l- substituted-3,4-dihydronaphth-2-yl)-4-alkyl-2E,4E-pentadieno ic acid amide of formula Ib including its tetralin derivatives of structure formulae lba where R and R ₁ to R ₇ are described as above, were synthesised from the corresponding Tetralone and eugenol and their derivatives by the known state of art as described in literature. Method-1

Alpha.-tetralone (1,2,3,4-tetrahydronaphtha-l-one) was first reacted with Vilsmeier reagent comprising of dimethylformamide and phosphorus oxychloride/phosphorus oxybromide or phosphorus tribromide mixture at 0-10 ⁰ C for 5-12 hrs, contents were neutralised with dilute alkali solution to produce l-halo-2-formyl-3,4-dihydronaphthalene. The l-halo-2-formyl- 3,4-dihydronaphthalene was condensed with an ylide (Wittig reagent, prepared from triphenylphosphine and ethyl bromoacetate/ethylchloroacetate) in equimolar mixture in presence of a strong base such as sodium hydride, sodium methoxide and the like at temperature 5 - 80 ⁰ C for 1 to 24 hrs in an ethereal medium such as diethyl ether, dimethoxyethane and the like benzene/toluene or dimethylformamide to yield corresponding 3-(l-halo-3,4-dihydro-naphth-2-yl)-acrylic acid ethyl ester which was hydrolysed with a strong alkali solution using sodium hydroxide or potassium hydroxide followed by acidification to furnish 3-(l-halo-3,4-dihydronaphth-2-yl) acrylic acid. A solution of aryl alkenoic acid as prepared above in an inert organic solvent such as benzene, dichloromethane was treated with thionyl chloride and excess of solvent removed in vacuo.

The acyl chloride intermediate thus obtained without purification was condensed with acyclic or cyclic or heterocyclic amine in inert organic solvent such as dichloromethane, benzene, diethyl ether and the like in the temperature range of 5-50 ⁰ C, and after the purification by crystallisation or column chromatography to produce amide of formula 1. For the preparation of compound of formula Ia, the acid of formula 1 was converted to its tetrahydro derivative by hydrogenation in presence of Pd/charcoal in polar solvent such as methanol or ethanol at ambient temperature and at 1-3 atmospheric pressure to obtain corresponding tetrahydro derivative which was converted to corresponding amides of formula Ia by the method described as above for the preparation of compound of formula 1. Alternatively Ia may also be prepared by hydrogenation of compound of formula 1 as such by the method as described above. .

Method-2

Eugenol l-(4'-hydroxy-3'-methoxy-phenyl)-2-propene was first reacted with alkyl/alϊyl/aryl alkyl halide using K ₂ CO ₃ and dry acetone mixture at reflux temperature for 24-50 hrs, the reaction mixture worked up by conventional method and the crude product purified by column chromatography over silica gel using hexane-ethyl acetate mixture as eluent to give the product as yellow viscous liquid. The eugenol alkyl ether was then reacted with dimethylformamide and phosphorus oxychloride/phosphorus oxybromide or phosphorus tri bromide mixture (N.S. Narasimhan, T. Mukhotadhyay, Teterahedron Lett. (1979) 1341- 1342. & N.S. Narasimhan, T. Mukhotadhyay, S.S. Kusurkar, Indian J. Chem. 2OB (1981) 546-548) at 0-10 ⁰ C for 40-72 hrs, contents neutralised with dilute alkali solution to produce 6,7-dia ^' lkoxy-3,4-dihydronaphthalene-2-carbaldehyde. The 6,7-dialkoxy-3,4 dihydronaphthalene-2-carbaldehyde was then condensed with malonic acid in presence of base such as piperidine using pyridine as solvent and the reaction left at room temperature for 24-30 hrs after that heated at 80-90 ⁰ C ₅ contents were cooled and poured into ice cold water than acidified and extracted with ethyl acetate, organic layer was washed with water and dried over anhydrous sodium sulphate, concentrate furnished 3-(6,7-dialkoxy-3,4- dihydro-naphth-2-yl)-acrylic acid.

A solution of aryl alkenoic acid as prepared above in an inert organic solvent such as benzene, dichloromethane treated with thionyl chloride and excess of solvent removed. The acyl chloride intermediate thus obtained without purification was condensed with acyclic or

cyclic or heterocyclic amine in inert organic solvent such as dichloromethane, benzene, diethyl ether and the like in the temperature range of 5-50 ⁰ C, and after the purification by crystallisation or column chromatography to produce amide of formula Ia.

Method-3 The tetralone was first reacted with dimethylformamide and phosphorus oxybromide or phosphorus tri bromide mixture at 0-10 ⁰ C for 5-24 hrs, contents neutralised with dilute alkali solution to produce l-halo-3,4-dihydronaphthalene-2-carbaldehyde . The l-halo-3,4- dihydronaphthalene-2-carbaldehyde was reacted with alkyl magnesium halide (alkyl halide C ₂ -C ₁ O) with constant stirring at ambient temperature in an anhydrous ether solvent such as diethyl ether, tetrahydrofuran and the like to produce corresponding l-(l-halo-3,4- dihydronaphth-2-yl)-alkan-l-ol which was treated with dimethylformamide and phosphorus oxychloride/phosphorus oxybromide or phosphorus tribromide mixture at 0-10 ⁰ C for 20-60 hrs, contents neutralised with dilute alkali solution to produce 3-(l-halo-3,4-dihydronaphth- 2-yl)-2-alkyl-propenal. The 3-(l-halo-3,4-dihydronaphth-2-yl)-2-alkyl-propenal was condensed with an ylide (Wittig reagent, prepared from triphenylphosphine and methyl/ethyl bromoacetate or methyl/ethyl chloroacetate in equimolar. mixture in presence of a strong base such as sodium hydride, sodium methoxide and the like at temperature 5-80 ⁰ C for 6-60 hrs in an ethereal medium such as diethyl ether, dimethoxyethane and the like or benzene/toluene or dimethylformamide to yield corresponding 5-(l-halo-3,4-dihydronaphth- 2-yl)-4-alkyl-2E,4E- pentadienoic acid ethyl ester which was saponified with a strong alkali solution using sodium hydroxide or potassium hydroxide followed by acidification to furnish 5-(l-halo-3,4-dihydronaphth-2-yl)-4-alkyl-2J?,4E-pentadienoi c acid and amidation with acyclic or cyclic or heterocyclic amine to afford compounds of formula Ib. For the preparation of compound of formula lba, the acid of formula Ib was converted to its tetrohydro derivative by hydrogenation in presence of Pd/charcoal in polar solvent such as methanol or ethanol at ambient temperature and 1-5 atmospheric pressure to obtain corresponding tetrohydro derivative which Was converted to corresponding amides of formula lba by the method described above for the preparation of compound of formula Ib. Alternatively lba may also be prepared by hydrogenation of compound of formula Ib as such by the method as described above. And excess of thionyl chloride and solvent removed. The acid chloride intermediate thus obtained was condensed with acyclic or cyclic

or heterocyclic amine or aryl amine or C-protected amino ester or unsubstituted and substituted allcylaryl amines.

Method-4

The α-tetralone was first converted to 1,2,3,4-tetrahydronapth-l-ol by reduction with sodium borohydride and the resulting alcohol reacted with dimethylformamide and phosphorus oxybromide or phosphorus tribromide mixture at 0-10 ⁰ C for 5-24 hrs, contents neutralised with dilute alkali solution to produce 3,4-dihydronaphthalene-2-carbaldehyde. The 3,4-dihydronaphthalene-2-carbaldehyde was reacted with malonic acid in presence of base such as piperidine using pyridine as solvent, and the reaction left at room temperature for 24-30 hrs after that heated at 80-90 ⁰ C, contents were cooled and poured into ice cold water than acidified and extracted with ethyl acetate, organic layer was washed with water and dried over anhydrous sodium sulfate, concentrate furnished 3-(3,4-dihydro-naphth-2- yl)-acrylic acid. The resulting acid above is taken in an inert organic solvent such as benzene, dichloromethane and treated with thionyl chloride in inert organic solvent such as dichloromethane or benzene and the like to give compounds of the formula Ia or alternately 3,4-dihydronaphthalene-2-carbaldehyde was reacted with alkyl magnesium halide (alkyl halide C ₂ -CiO, straight or branched) with constant stirring at ambient temperature in an anhydrous ether solvent such as diethyl ether, tetrahydrofuran and the like to produce corresponding l-(3,4-dihydronaphth-2-yl)-alkan-l-ol which was treated with dimethylformamide and phosphorus oxychloride/phosphorus oxybromide or phosphorus tribromide mixture at 0-10 ⁰ C for 20-60 hrs, contents neutralised with dilute alkali solution to produce 3-(3,4-dihydronaphth-2-yl)-2-alkyl-propenal. The 3-(3,4-dihydronaphth-2-yl)~2- alkyl-propenal was condensed with an ylide (Wittig reagent, prepared from triphenylphosphine and methyl/ethyl bromoacetate or methyl/ethyl chloroacetate) in equimolar mixture in presence of a strong base such as sodium hydride, sodium methoxide and the like at temperature 5-80 ⁰ C for 6-60 hrs in an ethereal medium such as diethyl ether, dimethoxyethane and the like or benzene/toluene or dimethylformamide to yield corresponding 5-(3,4-dihydronaphth~2-yl)-4-alkyl-2£,4is-pentadienoic acid ethyl ester which was saponified with a strong alkali solution using sodium hydroxide or potassium hydroxide followed by acidification to furnish 5-(3,4-dihydronaphth-2-yl)-4-alkyl-2j5 ^l ,4£- pentadienoic acid which on treatment with acyclic or cyclic or heterocyclic amine aryl

amine or C-protected amino ester or unsubstituted and substituted alkylaryl amines to afford compounds of formula Ib. For the preparation of compound of formula lba, the acid of formula Ib is converted to its tetrohydro derivative by hydrogenation in presence of Pd/charcoal in polar solvent such as methanol or ethanol at ambient temperature and 1-5 5 atmospheric pressure to obtain corresponding tetrahydro derivative which was converted to corresponding amides of formula lba by the method described above for the preparation of compound of formula Ib. Alternatively lba may also be prepared by hydrogenation of compound of formula Ib as such by the method as described above.

Method-5

10 The alpha-tetraione was first allowed to react with Grignard reagent (prepared from aryl halides & magnesium or unsubstituted or substituted- benzyl halide) with constant stirring at ambient temperature in an anhydrous ether solvent such as diethyl ether, tetrahydrofuran and the like to produce corresponding phenyl (unsubstituted or substituted) dihydronaphth- 2-yl-carbinol or benzyl (unsubstituted or substituted) dihydronaphthyl carbinol which was

[5 treated with dimethylformamide and phosphorus oxychloride/phosphorus oxybromide or phosphorus tribromide mixture at 0-10 ⁰ C for 20-60 hrs, contents neutralised with dilute alkali solution to produce 3-(3,4-dihydronaphth-2-yl)-2-aryl-propenal or 3-(3,4- dihydronaphth-2-yl)-2-benzyl-propenal. The propenal thus prepared was condensed with an ylide (Wittig reagent, prepared from tiϊphenylphosphine and methyl/ethyl bromoacetate or

10 methyl/ethyl chloroacetate) in equimolar mixture in presence of a strong base such as sodium hydride, sodium methoxide and the like at temperature 5-80 ⁰ C for 6-60 hrs in an ethereal medium such as diethyl ether, dimethoxyethane and the like or benzene/toluene or dimethylformamide to yield corresponding 5-(3,4-dihydronaphth-2-yl)-4-arylλenzyl- 2E _? 4E-pentadienoic acid ethyl ester which was saponified with a strong alkali solution

15 using sodium hydroxide or potassium hydroxide followed by acidification to furnish 5-(3,4- dihydronaphth-2-yl)-4-aryl or benzyl-2E, 4£-pentadienoic acid which on treatment .with acyclic or cyclic or heterocyclic amine aryl amine or C-protected amino ester or unsubstituted and substituted alkylaryl amines to afford compounds of formula Ib. For the preparation of compound of formula lba, the acid of formula Ib is converted to its i0 hexahydro derivative by hydrogenation in presence of Pd/charcoal in polar solvent such as methanol or ethanol at ambient temperature and 1-5 atmospheric pressure to obtain

corresponding tetrohydro derivative which was converted to corresponding amides of formula lba by the method described above for the preparation of compound of formula Ib. Alternatively lba may also be prepared by hydrogenation of compound of formula Ib as such by the method as described above.

Schematic diagram

1ba

R=halogen, hydrogen, alkyl (Cl to ClO), substituted/unsubstituted aryl or benzyl. RlR2R3R4=hydrogen, nitro, halo, hydroxy, alkyloxy, alkenyloxy, aryloxy, substitutedpyranyl radical unsubstituted pyranyl radical or Rl , R4 represnet hydrogen and

R2, R3 (R2=R3) represent hydrogen, hyroxyl, halo, nitro, alkoxyl ^' (Cl-ClO), alkenoxyl(Cl- ClO), aroyloxyl , substituted aroyloxyl , or Rl , R4 represnet hydrogen and R2+R3 together represent 1,3-dioxol or 1,4-dioxol ;and R5=R6= hydrogen or normal or branched chain Ci to C ₁ O alkyl group or phenyl or benzyl radical or R5+R6=heterocyclic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N-methylpiperazinyl, oxazolyl, N- methylpiperazinyl, pyrrolyl, imidazolyl, oxazolyl or an amino acid such as alaninyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl etc. R7=normal or branched chain Cl to ClO alkyl group, phenyl, benzyl radical

R2=R3=H,OR(R=C1 Io C10, Aryl, Substituted aryl, Benzyl, Substituted benzyl x = H, Cl. Br, Phenyl, Substituted Phenyl, Benzyl, Substituted Benzyl, alkyl

R2+R3=1 ,3-dioxal, 1,4-dioxal

R5=R6=H, normal αr branched chain C1 to C10 alkyl group or phenyl or benzyl radical

R5+R6=heterocyc!ic amine radical such as piperidinyl, pyrrolidinyl, morpholinyl, piperazinyl, N-melhylplperazlnyl, oxazolyl, N-methylpipera∑inyl, pyrrolyl, imidazolyl, oxazolyl, thiooxazole, an amino acid such as aianlnyl, leucinyl, phenylalaninyl, tyrosinyl, glycylglycinyl, alanylalaninyl and Ihβ like and optionally converting them to (heir salts by method known In the art of synthesis,

R7= normal or branched chain C1 to C10 alkyl groups or phenyl or benzyl radical

branched chain) (substituted or unsubstituted)

y _U nsubstltufcd)

(R=CH3, C ₁ -C ₁₀ straight or branched chain)

or R=aryl or benzyl (substituted or unsubstituted)

(R=CH ₃ , C ₁ -C ₁₀ straight or R=halo,alkyl,aryl, benzyl branched chain)

X=CI,Br,alkyl,aryl,benzyl X=CI,Br,alkyl,aryl,benzyl

R=alky!,aryl, benzyl R=alkyl,aryl,benzyl

Bio efficacy New antibiotics are continued to be discovered at a rate of >500 per year, but these almost invariably belong to previously identified classes of compounds, making it likely that pathogens will be able to rapidly build up resistance to these "new" drugs. The increasing threat of drug-resistant pathogens is causing a renewed interest in the discovery of novel antibiotics. Present invention is focused on 'potentiators' involved wherein such agents, which by themselves are not therapeutic entities but when combined with an active drug, lead to the potentiation of the pharmacological effect of the drug. Such formulations/ combinations have been found to increase the bio-efficacy of a number of drugs even when reduced doses of drugs are present in such formulations. For example, patent nos. IP 172690; IP 176433 . and US 5744161 disclose such art. These compounds are not only capable of increasing bioavailability of a wide variety of therapeutic agents but are also capable of enhancing bio- efficacy through a variety of mechanisms. As a result newer understanding has emerged about the factors involved in decreased cellular concentrations of drugs at which they failed to attain therapeutic levels and the strategies that make it possible to enhance the bio- efficacy of these active drugs even at lower concentrations compared to standard high dosing. Some of these factors are:

(a) Increasing the penetration or entry of the active drug into the pathogen even where

tney become persistors, besides inhibiting the capability of pathogens and abnormal tissues to reject the drug. This would eventually ensure the enhanced killing of the pathogenic microorganisms, which are otherwise inaccessible to the active drug.

(b) Chemo resistance is a major problem in drug therapy. The mechanisms underlying the clinical phenomena of de novo and acquired drug resistance may arise from alterations at any step in the cell-killing pathway. These include drug transport, drug metabolism, drug targets, cellular repair mechanisms and the ability of cells to recognize a harmful toxin or pathogen. A common mechanism of reduced cellular drug accumulation is the increased expression Multi ■ Drug Resistance pumps (MDRs). The present invention also proves that the compounds described here inhibit the bacterial efflux, as a result of which there is more of accumulation and decreased efflux of ethidium bromide is used as substrate to gauge the efflux of the drugs by the extent of fluorescence observed.

(c) Immunological intervention through nitric oxide (NO) production, CMI and/or humoral immune potentiation with favourable influence on the Th 1/ Th 2 balance.

(d) Sensitization of specific receptors like proteins, DNA, RNA etc thus potentiating and prolonging the effect leading to enhanced antibiotic activity against pathogens, and disorders. Adequate experimental evidences have been gained in respect of several of these mechanisms, (B. Ray, S. Medda, S. Mukhopadhyay, M.K. Basu, Indian J. Biochem. Biophys. 36 (1999) 248-251) modulating the membrane fluidity, which may alter the activity of membrane, bound transporter proteins. The overall permeability changes may affect (i) specific ion transporter channels, and (ii) also lead to bulk movement of lipophilic solutes along the paracellular pathway. Such membrane changes have also been evidenced in the action of several polyene antibiotics (J. Milhaud, J. Bolard, P. Benveniste, M.A. Hartmann, Biochim.

. Biophys. Acta. 943 (1988) 315-325).

(e) Potentiating the mechanism of action of drugs and thus increasing their efficacy at lower doses e.g. inhibition of RNA polymerase transcription leading to potentiation of the effect of rifampicin at less than half the standard dose. The products of the present invention are novel mechanism based pharmaceutical entities acting through synergism and/or additive effect so that drugs contained in the

tormulation are more bio-efficaceous as a result of one or more of the mechanism as revealed above and thereby increasing the sensitivity of the target cell to an anti-infeetive.

Description of the preferred embodiment The Mrug' in the present invention refers to a chemical entity capable of affecting organism's patho-physiology and used for the treatment or prevention of disease. Drugs include a number of classes of compounds, but not limited to aminoglycoside, penicillins, cephalosporins and other β-lactam agents, macrolides, glycopeptides, fluoroquinolones, tetracyclines, first and second line anti-TB drugs, anti-leprosy, antiviral, polyene, triazole, and imidazoles and combinations like pyrimidines, sulphamethoxazole. Drugs may be a prodrug, activated or metabolised form, consisting of charged, uncharged, hydrophilic, hydrophobic or zwitter-ion species which make their entry by simple diffusion, carrier mediated transport dependent and not dependent on energy requirements, through ion and/ or voltage gated channels. The 'potentiator' refers to aromatic amides of the formulae Ia, laa, Ib, lba selected from the following set of compounds prepared by the method described in the examples. 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid piperidide 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid pyrrolidide 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid morpholide 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid n-octylamide

3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid isobutylamide 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid isopropylamide 3-(l -chloro-3,4-dihydfonapth-2-yl)-acrylic acid N,N-diethylamide 3 -(I -chloro-3,4-dihydronapth-2-yl)-acrylic acid N,N-diisopropylamide 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acidp-methoxyanilide

3 -(I -chloro-3,4-dihydronapth-2-yl)-acrylic acid 3,4-methylenedioxyanilide 3-(l -chloro-3,4-dihydro-napth-2-yl)-acrylic acid o-methylanilide 3-(l -chloro-3,4-dihydronapth-2-yl)-acrylic acid benzylamide 3-(l -chloro-3,4-dihydronapth-2-yl)-acrylic acid p-nitroanilide 3-(l -chloro-3,4-dihydro-napth-2-yl)-acrylic acid p-fluoroanilide

3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acidp-carboxyanilide

3 -(I -chloro-3,4-dihydronapth-2-yl)-acrylic acid N,N-diphenylamide 3 -(I -chloro-3,4-dihydronapth-2-yl)-acrylic acid N-methylpiperazide 3 -( 1 -chloro-3 ,4-dihydronapth-2-yl)-acrylic acid />-methylanilide 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid «-butylamide 5 3 -(I -chloro-3 ,4-dihydronaρth-2-yl)-acrylic acid anilide

3-(l -chloro-3, 4-dihydronapth-2-yl)-acrylic acid imidazolide 3 -( 1 -chloro-3 ,4-dihydronapth-2-yl)-acrylic acid ø-methoxyanilide 3 -( 1 -chloro-3 ,4-dihydronapth-2-yl)-acrylic acid N,N-diisobutylamide '3-(l-bromo-3,4-dihydiOnapth-2-yl)-acrylic acid piperidide

LO 3 -( 1 -bromo-3 ,4-dihydronapth-2-yl)-acrylic acid pyrrolidide

3 -(I -bromo-3, 4-dihydronapth-2-yl)-acrylic acid morpholide 3 -(I -bromo-3 ,4-dihydronapth-2-yl)-acrylic acid isobutylamide 3-(l -bromo-3,4-dihydronapth-2-yl)-acrylic acid N,N-diisopropylamide 3-(l-bromo-3,4-dihydro-napth-2-yl)-acrylic acid «-butylamide

15 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid N-methylpiperazide

3-( 1 -bromo-3 ,4~dihydronapth-2-yl)-acrylic acid N,N-diethylamide 3-(l -bromo-3 ,4-dihydro-napth-2-yl)-acrylic acid imidazolide 3-(l -bromo-3 ,4-dihydronapth-2-yl)-acrylic acid />-hydroxypiperidide 3-(3,4-dihydronaphth-2-yl)-acrylic acid isobutylamide

'0 3-(3,4-dihydronaphth-2-yl)-acrylic acid N,N-diisopropylamide ^'

3-(3.4-dihydronaphth-2-yl)-acrylic acid piperidide 3-(3,4-dihydronaphth-2-yl)-acrylic acid pyrrolidide 3-(3,4-dihydronaphth-2-yl)-acrylic acid morpholidide 3-(3,4-dihydronaphth-2-yl)-acrylic acid/>-methoxy anilide

:5 3-(3,4-dihydronaphth-2-yl)-acrylic acid «-octylamide

3-(3,4-dihydronaphth-2-yl)-acrylic acid N,N-diethylamide 3-(3,4-dihydronaphth-2-yl)-acrylic acid anilide 3-(3,4-dihydronaphth-2-yl)-acrylic acid 3,4-methylenedioxy anilide 3-(l-benzyl-3,4-dihydro-naρth-2-yl)-acrylic acid «-octylamide

0 3-(l-benzyl-3,4-dihydro-napth-2-yl)-acrylic acid piperidide

3-(l-benzyl-3,4-dihydro-napth-2-yl)-acrylic acid pyrrolidide .

3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid morpholide 3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid isobutylamide 3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid N,N-diisopropylamide 3 -( 1 -benzyl-3 ,4-dihydronapth-2-yl)-acrylic acid ^-hydroxy piperidine 5 3 -(6,7-dimethoxy-3 ,4-dihydronaphth-2-yl)-ρropenoic acid piperidide

3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-ρropenoic acid moφholide 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid pyrrolidide 3 -(6,7-dimethoxy-3 ,4-dihydronaphth-2-yl)-propenoic acid n-octylamide 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid isobutylamide

10 3 -(6,7-dimethoxy-3,4-dihydronaρhth-2-yl)-ρropenoic acid rø-butylamϊde

3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid n-propylamide 3 -(6,7-dimethoxy-3 ,4-dihydronaρhth-2-yl)-propenoic acid isopropylamide 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid N,N-diisopropylamide 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid anilide

15 3-(6,7-diraethoxy-3,4-dihydronaphth-2-yl)-piOpenoic-acid-o-m ethylanilide

3 -(6,7-dimethoxy-3 ,4-dihydronaphth-2-yl)-propenoic acid /7-raethylanilide 3 -(6,7-dimethoxy-3 ,4-dihydronaphth-2-yl)-propenoic acid /7-methoxyanilide 5-( 1 -chloro-3 ,4-dihydronaphth-2-yl)-4~methyl-2£,4i?-pentadienoic acid isobutylamide

-0 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2£',4£'-penta dienoic acid N ₅ N- diisopropylamide

5-( 1 -chloro-3 ,4-dihydronaphth-2-yl)-4-methyl-2E,4E-pentadienoic acid piperidide 5-(l -chloiO-3,4-dihydronaphtli-2-yl)-4-methyl-2E,4£-pentadienoi c acid pyrrolidide 5-(l-chloro-3.4-dihydronaphth-2-yl)-4-methyl-2£,4£'-pentad ienoic acid morpholide

!5 5-(l -chloro-3, 4-dihydronaphth-2-yl)-4-ethyl-2£',4^'-ρentadienoic acid piperidide

5-(l-chloro-3,4-dihydronaphth-2-yl)-4-ethyl-2£,4£-pentadie noic acid pyrrolidide 5-( 1 -chloro-3 ,4-dihydronaphth-2-yl)-4-ethyl-2E,4£'-ρentadienoic acid isobutylamide 5~(l-chloro-3,4-dihydronaphth-2-yl)-4-ethyl-2£ _? 4£'-pentadienoic acid N,N- diisopropylamide.

0 3 -( 1 -methyl-3 ,4-dihydronapth-2-yl)-acrylic acid piperidide

3-(l-methyl-3,4-dihydronapth-2-yl)-acrylic acid pyrrolidide

3-(l-methyl-3,4-dihydronapth-2-yl)-acrylic acid morpholide 3 -(I -methyl-3,4-dihydronapth-2-yl)-acrylic acid isobutylamide 3-(l-methyl-3,4-dihydronapth-2-yl)-acrylic acid N,N-diisopropylamide 3-(l -chloro- l,2,3,4-tetrahydiOnapth-2-yl)-propanoic acid piperidide 3-(l-chloro-l,2,3,4-tetrahydronapth-2-yl)-propanoic acid pyrrolidide

3-(l-chloro-l,2,3,4-tetrahydronapth-2-yl)-propanoic acid morpholide 3 -( 1 -chloro -1,2,3 ,4-tetrahydronaρth-2-y l)-propanoic acid n-buty lamide 3 -( 1 -chloro- 1 ,2,3 ,4-tetrahydiOnapth-2-yl)-propanoic acid isobutylamide 3-(l-chloro-l,2,3,4-tetrahydronapth-2-yl)-propanoic acid π-octylamide 3-(l-chloro-l,2,3,4-tetrahydronapth-2-yl)-propanoic acid N,N-diethylamide

3-(l -chloro-1 ,2,3 ,4-tetrahydronapth-2-yl)-propanoic acid N,N-diisopropylamide 3 -( 1 -bromo- 1 ,2,3 ,4-tetrahydronapth-2-yl)-propanoic acid piperidide 3-(l-bromo-l ,2,3,4-tetrahydronapth-2-yl)-propanoic acid isobutylamide 3-(l -bromo- 1 ,2,3 ,4-tetrahydronapth-2-yl)-propanoic acid ^-methoxyanilide 3-(l -bromo- 1 ,2,3,4-tetrahydronapth-2-yl)-propanoic acid N,N-diisopropylamide

3-(l-bromo-l,2,3,4-tetrahydronapth-2-yl)-propanoic acid pyrrolidide 3-(l -bromo- 1 ,2,3,4-tetrahydronapth-2-yl)-propanoic acid ø-methylanilide 3-(l-bromo-l, 2,3 ,4-tetrahydronapth-2-yl)-propanoic acid />-methylanilide 5-( 1 -chloro- 1 ,2,3 ,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid N ₅ N- diisopropylamide

5-(l-chloro-l,2,3,4-tetrohydronaphth-2-yl)-4-methyl-penta noic acid isobutylamide 5-(l -chloro-1 ,2,3,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid piperidide 5-(l-chloro-l,2,3,4-tetrohydronaphth-2-yl)-4-niethyl-pentano ic acid pyrrolidide 5-(l -chloro-1 ,2,3,4-tetrohydronaphth-2-yl)-4-methyl-ρentanoic acid n-octylamide 5-(l -chloro-1, 2,3 ,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid anilide

5-(l-chloro-l ,2,3,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid morpholide. 5-(l -chloro-1, 2,3, 4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid glycine methyl ester amide 5-(l-chloro-l,2,3,4-tetrohydronaphth-2-yl)-4-methyl-ρentano ic acid alanine methyl ester amide

5-(l -chloro-1, 2,3, 4-tetrohydronaphth-2-yl)-4-methyl-ρentanoic acid phenyl alanine

methyl ester amide

5 -( 1 -chloro- 1,2.3 ,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid triptamine amide.

The combination of particular amount of potentiator with particular amount of the drug i.e the doses of efflux pump inhibitor and the antimicrobial agent which are useful in combination as a treatment are therapeutically effective which generally refers to the inhibition of the normal metabolism of the micro-organisms responsible for microbial infection. In the present invention, a therapeutically effective amount means those amounts of the efflux pump inhibitor and anti-microbial agent which, when used in combination produce the desired therapeutic effect as judged by the model animal infection studies. In particular embodiment, the efflux pump inhibitor and anti-microbial agent are combined in predetermined proportions and thus a therapeutically effective amount would be an amount of the combination and the amount of individual components i.e. efflux pump inhibitor and the anti-microbial agent as well as the combination of two can be determined by one of the skill in the art and the amount of the combination will vary depending upon several factors such as the particular microbial strain /isolate used in the study and the particular efflux pump inhibitor and the anti-microbial agent used besides depending upon the weight, sex, age etc of the animal/patient on whom the combination of the efflux pump inhibitor and the anti-microbial agent is tested. A pharmaceutical carrier is generally an inert bulk agent added to make the ingredients achieve superior ad mixing and can be solid or liquid. The inert parts of standard pharmaceutical compositions used in this process are also part of the present invention.

Study design

The checker board method:

This is the most frequently used method to access the antimicrobial combinations in vitro. The term "checkerboard" refers to the pattern (of tubes or microtiter plate wells) formed by multiple dilutions of two drugs being tested (Eliopoulos GM, Moelle ^' ring RC. Antimicrobial Combinations, in: Antibiotics in Laboratory Medicine: USA: Williams & Willάns). In the present study the checkerboard consisted of columns in which each tube (or well) contains

the same amount of the standard drug (antibacterial/antifungal/anti-TB/antiviral) being diluted along the x-axis and rows in which each tube (or well) contains the same amount of the potentiator being diluted on the y-axis. As a result each square in the checkerboard (which represents one tube/ well or plate) contained a unique. This chequerboard technique can be performed with liquid or semisolid (agar) media.

Agar Method:

In this method the agar (Mueller Hinton agar, Middlebrook 7H10 agar) was autoclaved and allowed to cool to 55 ⁰ C to 50 ⁰ C. The combination of the standard drug and the potentiator was added to the agar. Serial two fold dilutions of each of standard drug and the potentiator were prepared in appropriate solvents. In order to maintain the desired concentrations of both agar and drugs, and to rule out the effect of solvent, the volume of solvent (containing standard drug or potentiator) added to agar was kept small (i.e. 5% of the total volume). After the agar plates have been poured and allowed to dry, the bacteria to be tested were applied to the surface of agar with a replicating device designed to deliver a standard inoculum (approx 10 ⁴ cfu|spot). The plates were incubated at 37 ⁰ C for 24 hrs (3 weeks in case of Mycobacterium tuberculosis).

-Broth Method: The above-mentioned checkerboard was also performed with liquid media in a microtiter plate format. This method was used to study the combination of antibacterial/antifungal/ antiviral drugs with potentiator.

Toxicity evaluation of 3-(l-chloro-3,4-dihydro-napth-2-yl)-acrylic acid N,N- diisopropylamide of formula Ia Toxicity evaluation of 3-(l-chloro-3,4-dihydro-napth-2-yl)-acrylic acid N,N- diisopropylamide of formula Ia (example-5). In acute toxicity studies an LD ₅₀ (oral) was found to be >3.0 gm/kg in mice. In subacute studies the effect of 3-(l-chloro-3,4-dihydro- napth-2-yl)-acrylic acid N,N-diisopropylamide of formula Ia (example-8) at 20, 40 and 100 mg/kg was investigated for 28 days. Parameters monitored were: food/water consumption, body weight, organ weight, haematological and clinical chemistry profile. No adverse effects were observed. Safety pharmacology studies (CNS, CVS and GIT profile) did not

reveal any abnormality.

The following examples are intended to demonstrate some of the preferred embodiments but in no way be construed so as to limit the scope of the invention. Any person skilled in the art can design more formulations, which may be considered as part of the present invention.

Example 1

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yI)-acrylic acid piperidide of formula-l where 1) Preparation of l-chloro-2-formyl-3,4-dihydronaphthalene

To a chilled solution of α tetratone (2Og, 134 mmol) in dry DMF (50 ml), POCl ₃ (12.6 ml) was added drop wise at 0-5 ⁰ C for lhr and the resulting mixture was stirred at room temperature for 24 hrs. The reaction mixture was poured into ice-cold water (150 ml) containing sodium acetate (2Og). The contents were extracted with ethyl acetate (3x100 ml). The combined extracts were pooled and washed with water (3x50 ml), dried over anhydrous sodium sulfate and concentrated on rota vapour to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C: ethyl acetate (98:2) as an eluent to gave yellow viscous oil l-chloro-2-formyl-3,4-dihydronaphthalene yielded (24.8g, 95%), analysed for C ₁₁ H ₉ ClO; calcd C 68.58 H 4.71 Cl 18.40%, found C 69.04 H 4.72 Cl 18.41%) 2) Preparation of 3-(l-chloro-3,4-dihydronaphth-2-yI) acrylic acid

To a mixture of l-chloro-2-formyl-3,4-dihydronaphthalene (18.0g, 93 mmol) in pyridine (50 ml) and piperidine (5 ml), malonic acid (18g 1:2 eq) was added and the reaction mixture kept at room temperature for 52 hrs and heated on water bath for 6 hrs. To the cooled contents added 50% aqueous HCl solution and the resulting precipitate filtered, washed with water, dried and crystallized in pet.ether/ethylacetate to gave 3-(l-chloro-3,4-dihydronaphth- 2-yl) acrylic acid yielded (19.6g 90%), analysed for C ₁₃ Hi ₁ ClO ₂ ; calcd C 66.53 H 4.72 Cl 15.11%, found C 66.99 H 4.77 Cl 15.31%. ¹ H NMR (200 MHz, CDCl ₃ ): δ 2.63 (2H, t, J=7.82 Hz, CH ₂ ), 2.91 (2H, t, J=7.82 Hz, CH ₂ ), 6.11 (IH, d, J=15.80 Hz, CH=CHCO), 7.25 (4H, m, 4xAr-H), 8.25 (IH, d, J=I 5.83 Hz, CH=CHCO).

3) Preparation of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid piperidide._

To the compound 3-(l-chloro-3,4-dihydronaphth-2-yl) acrylic acid (500mg, 2.31mmol) in dry benzene (50 ml) added freshly distilled thionyl chloride (1.0 ml) and refluxed for lhr, excess of thionyl chloride removed in vacuo and thereafter condensed with dry benzene

5 solution of piperidine (1.0 ml) and stirred for 30 min. The organic layer washed with water (2x25 ml), dried over anhydrous sodium sulfate and evaporated on rotary evaporator to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C: ethyl acetate (90:10) as an elueht to gave the title compound (620mg, 94%), analysed for C ₁₈ H ₂₀ ClNO; calcd C 71.63 H 6.68 Cl 11.75 N 4.64%, found C 72.02 H 6.74 Cl 12.01 N

10- 4.71%. ¹ H NMR (200 MHz CDCl ₃ ): δ 1.62 (6H, bs, 3xCH ₂ ), 2.61 (2H, d, J=8.2Hz, CH ₂ CH ₂ ), 2.88 (2H, d, J=8.2Hz, CH ₂ CH ₂ ), 3.56 (4H, m, 2xCH ₂ ), 6.54 (IH, d J=I 5.43 Hz, CH=CHCO), 7.23 (3H, m, 3xAr-H), 7.71 (IH, dd, J=2.4, 9.0 Hz, Ar-H), 8.03 (IH, d, 15.44 Hz, CH=CHCO). Example 2

'.5 Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid pyrrolidide of formula 1 where R=Cl and R ₅ +R ₆ =pyrrolidine

This was similarly prepared, as described in example 1, except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and pyrrolidine. Yield (90%), analysed for C ₁₈ H ₂₀ ClNO; calcd C 71.63 H 6.68 Cl l l!75 N 4.64%, found C71.99 H 6.82 Cl 12.11 N

10 4.66%. ¹ H NMR (CDCl ₃ ): δ 1.96 (4H, m), 2.66 (2H, t, J=5.0 Hz), 2.89 (2H, t, J=5.0 Hz), 3.51 (2H, t, J=6.5 Hz), 3.65 (2H, t, JN5.5 Hz), 6.57 (IH, d, J=15.36 Hz), 7.25 (3H, m), 7.70 (IH, d, >2.76 Hz), 8.06 (IH, d, J=15.3 Hz).

Example 3

5 Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yI)-acrylic acid morpholide of formula 1 where Ri=R ₂ =Ra=Ri=H, R=Cl and R ₅ +R6=morpholidine

This was similarly prepared, as described in example 1, except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and morpholine. Yield (95%), analysed for C ₁₇ H ₁₈ ClNO ₂ ; calcd C 67.21 H 5.97 Cl 11.67 N 4.61%, found C 68.11 H 6.00 Cl 12.1 N 0 4.59%. ¹ H NMR (CDCl ₃ ): δ 2.68 (2H, t, J=8.4 Hz), 2.87 (2H, t, J=8.4 Hz), 3.31 (4H,- m), 3.73 (4H, m), 6.77 (IH, d, J=15.3 Hz), 7.26 (3H, m), 7.69 (IH, d, J=5.5 Hz), 8.07 (IH, d,

J=I 5.3 Hz)

Example 4

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid λi-octylamide of formula 1 5 where

This was similarly prepared, as described in example I ₃ except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid and /i-octylamine. Yield (73%), analysed for C ₂ iH ₂₈ CINO; calcd C 72.92 H 8.16 CI 10.25 N 4.05%, found C 73.11 H 8.22 Cl 10.44 N 4.10%. ¹ HNMR (CDCl ₃ ): δ 0.87 (3H, t, /=6.68 Hz), 1.28 (12H, m), 1.55 10 (2H, t, /=7.16 Hz), 2.61 (2H, t, /=5.20 Hz), 2.87 (2H, t, /=5.14 Hz), 6.30 (IH, d, /=15.5 Hz), 7.24 (3H, m), 7.69 (IH, d, /=2.23 Hz), 8.0 (IH, d, /=15.5Hz).

Example 5

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid isobutylamide of formula 1 15 where R=CI and R ₅ +R6=isobutylamine.

This was also similarly prepared, as described in example 1, except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and isobutylamine. Yield (73%), analysed for Ci ₇ H ₂₀ ClNO; calcd C 70.46 H 6.96 Cl 12.23 N 4.83%, found C 70.61 H 7.01 Cl 12.61 N 4.88 %. ¹ HNMR (200 MHz CDCl ₃ ): δ 0.94 (6H, d, J=6>7 Hz, CH (CRi) ₂ ), 1-83 ^> 0 (IH ₃ m, CH(CH ₃ ),), 2.62 (2H, t, J=7.75 Hz ₅ CH ₂ -CH ₂ ), 2.88 (2H, t, J=7.76 Hz, CH ₂ CH ₂ ), 3.11 (2H, d, J=6.4 Hz, CH ₂ CH), 6.33 (IH, d, J=15.54 Hz, CH=CHCO), 7.25 (3H, m, 3xAr- H), 7.69 (IH, m, Ar-H), 8.01 (IH, d, J=I 5.57 Hz, CH=CHCO).

Example 6

\5 Synthesis of 3-(l-chloro-3,4-dihydroπapth-2-yI)-acrylic acid isopropylamide of formula 1 where Ri=R ₂ =R ₃ =Ri=H, R=CI and R ₅ +R ₆ =isopropylamine.

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and isopropyl amine. Yield (90%), analysed for Ci ₆ Hi ₈ ClNO; calcd C 69.68 H 6.58 Cl 12.86 N 5.08%, found C 70.02 H 6.66 Cl 13.11 N 0 5.11%. ¹ H NMR (CDCl ₃ ): δ 1.19 (6H, d, J=6.58 Hz), 2.61 (2H, t, J=8.3 Hz), 2.88 (2H, t, J=8.3 Hz), 4.07 (IH, m), 6.28 (IH, d, J=6.28 Hz), 7.24 (3H, m), 7.69 (IH, d, J=4.5 Hz),

8.00 (IH ₅ d, J=15.6 Hz).

Example 7

Synthesis of 3-(l-chIoro-3,4-dihydronapth-2-yl)-acrylic acid-N,N-diethylamide of 5 formula 1 where Ri=R ₂ =Ra=RpH, R=CI and Rs+R^JN^N-diethylamine.

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and N,N-diethylamme. Yield (85%), analysed for C ₂ ιH ₂₈ ClNO; calcd C 72.92 H 8.16 Cl 10.25 N 4.05%, found C 73.11 H 8.22 Cl 10.55 N 4.11%. ¹ HNMR (CDCl ₃ ): δ 1.20 (6H ₅ m), 2.65 (2H, t, J=5.24 Hz), 2.88 (2H, t, J=5.O3 Hz), 10 3.49 (4H ₅ m), 6.67 (IH, d, J=15.28 Hz) ₅ 7.23 (3H ₅ m), 7.69 (IH, d, J=2.23 Hz), 8.07 (IH, d, J=I 5.28 Hz).

Example 8

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid-N,N-diisopropylamide of 15 formula 1 where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl and Rs+R ₆ =N,N-diisopropylamine.

This was similarly prepared, as described in example I ₅ except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and. diisopropylamine Yield (98%), analysed for C ₁₉ H ₂₄ ClNO; calcd C 71.80 H 7.61 Cl 1 1.15 N 4.41%, found C 72.61 H 7.69 Cl 11.23 N 4.48 %. ¹ H NMR (200 MHz CDCl ₃ ): δ 1.23 & 1.27 (6H each, d, J=6.7 Hz each, 2xCH .0 (CH ₃ ) ₂ ), 1.96 (2H, m, 2xCH(CH ₃ ) ₂ ), 2.70 (2H, d, J=7.45 Hz, CH ₂ CH.), 2.89 (2H, d, J=7.45 Hz, CH ₂ CH ₂ ), 6.80 (IH, d, J=15.54 Hz, CH=CHCO), 7.30 (3H, m, 3xAr-H), 7.70 (IH, m, Ar-H), 7.97 (IH, d, 15.57 Hz, CH=CHCO).

Example 9 i5 Synthesis of 3-(l-chIoro-3,4-dihydronapth-2-yl)-acryIic acid />-methoxyanilide of formula 1 where

This was similarly prepared, as described in examplel, except the starting materials were 3- (l-chloro-3,4-dih3^dronapth-2-yl)-acrylic acid and jσ-anisidine. Yield (89%), analysed for C ₂₀ H ₁₈ ClNO ₂ ; calcd C 70.69 H 5.34 Cl 10.34 N 4.12%, found C 71.43 H 5.39 Cl 1039 N ^; 0 4.26%. ¹ H NMR (200 MHz CDCl ₃ ): δ 2.64 (2H, t, J=7.6 Hz) ₅ 2.91- (2H, t, J=7.6 Hz), 3.73 (3H, s), 6.55 (IH ₅ d, J=15.40 Hz), 2.91 (2H, d, J=8.97 Hz), 7.33 (2H ₅ d ₅ J=6.9 Hz), 7.64

(4H ₅ m), 7.99 (IH, d, J=15.4 Hz), 10.15 (IH, s).

Example 10

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid-3,4-methylenedioxy- 5 anilide of formula 1 where R=Cl and R ₃ +R ₆ =3,4-methylenedioxy- aniline.

This was similarly prepared, as described in examplel, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acryiic acid and 3,4-methylenedioxy aniline. Yield (84%), analysed for C ₂₀ Hi ₆ ClNO ₃ ; calcd C 67.90 H 4.56 Cl 10.02 N 3.96%, found C 68.64 H 5.59 10 Cl 10.14 N 4.03%.

Example 11

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid ø-methylanilide of formula

1 where

15 This was similarly prepared, as described in example 1, except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and ø-methylaniline. Yield (90%), analysed for C ₂₀ HisClNO; calcd C 74.18 H 5.60 Cl 10.95 N 4.33%, found C .74.26 H 5.82 Cl 11.03 N 4.39%.

^> 0 Example 12

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid benzylamide of formula 1 where R=Cl and R _s +R ₆ =benzylamine.

This was similarly prepared, as described in example 1, except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and benzylamine. Yield (73%), analysed for 15 C ₂₀ Hi ₈ ClNO; calcd C 74.18 H 5.60 Cl 10.95 N 4.33%, found C 74.26 H 5.79 Cl 10.99 N 4.38%.

Example 13

Synthesis of 3-(l-chIoro-3,4-dihydronapth-2-yl)-acrylic acid />-nitroaniIide of formula 1 0 where

This was similarly prepared, as described in example 1, except the starting materials were 3-

(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and p-nitroaniline. Yield (73%), analysed for C ₁₉ H ₁₅ ClN ₂ O ₃ ; calcd C 64.32 H 4.26 Cl 9.99 N 7.90%, found C 64.92 H 4.31 Cl 10.07 N 7.99%.

5 Example 14

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid p-fluoroanilide of formula 1 where R=Cl and

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and p-fiuoro aniline. Yield (71%), analysed 10 for Ci ₉ Hi ₅ ClFNO; calcd C 69.62 H 4.61 Cl 10.82 F 5.80 N 4.27%, found C 70.44 H 4.69 Cl 10.90 N 4.32%.

Example 15

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid />-carboxyaniIide of 15 formula 1 where

This was similarly prepared, as described in example 1, except the starting materials were

3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and p-carboxyaniline. Yield (73%), analysed for Ci ₉ Hi ₆ ClNO ₃ ; calcd C 67.90 H 4.56 Cl 10.02 N 3.96%, found C 68.80 H 4.60

Cl 10.09 N 3.99%. 20

Example 16

Synthesis of 3-(l-chloro-3, 4-dihydronapth-2-yl)-acrylic acid N,N-diphenylamine of formula 1 where Ri-R ₂ =Rs=Ri=H, R=Cl and R ₅ +R ₆ =N,N-diphenylamine.

This was similarly prepared, as described in example 1, except the starting materials were .5 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and diphenylamine. Yield (83%), analysed for C ₂₅ H ₂₀ ClNO; calcd C 77.81 H 5.22 Cl 9.19 N 3.63%, found C 78.69 H 5.29 Cl 9,27 N

3.68%.

Example 17

»0 Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid N-methylpiperazide of formula 1 where

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and N-methylpiperazine. Yield (85%), analysed for C ₁₈ H ₂ iClN ₂ O; calcd C 68.24 H 6.88 Cl 11.19 N 8.84%, found C 69.16 H 6.89 Cl 11.24 N 8.91%.

Example 18

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acryIic acid p-methylanilide of formula 1 where R ₁ =R ₂ =R ₃ =R ₄ =H, R=Cl and R ₅ +R<;=/;-methyIaniline.

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and j9-methylaniline. Yield (90%), analysed for C ₂₀ H ₁₈ ClNO; calcd C 74.18 H 5.60 Cl 10.95 N 4.33%, found C 75.10 H 5.66 Cl 10.99 N 4.39%.

Example 19 Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yI)-acryIic acid /ι-butylamide of formula 1 where Ri=R ₂ =R ₃ =Ri=H, R=Cl and R _s +R ₆ =«-butylamine.

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and π-butylamine. Yield (90%), analysed for C ₁₇ H ₂₀ ClNO; calcd C 70.46 H 6.96 Cl 12.23 N 4.83%, found C 71.49 H 7.00 Cl 12.27 N 4.89%.

Example 20

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid anilide of formula 1 where This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and aniline. Yield (94%), analysed for Ci ₉ H ₁₆ ClNO; calcd C 73.66 H 5.21 Cl 11.44, N 4.52%, found C 74.54 H 5.26 Cl 11.47 N 4.59%.

Example 21

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid imidazolide of formula 1

where R ₁ =R ₂ =R ₃ =R _t =H, R=Cl and R ₅ +R _δ =imidazole.

This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and imidazole. Yield (94%), analysed for C16H17C1N ₂ O; found C 66.55 H 5.93 Cl 12.98 N 9.70%, calcd C 66.94 H 5.99 Cl 13.02 N 5 9.77%.

Example 22

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid ø-methoxyanilide of formula 1 where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl and Rs+R^ø-methoxyaniline.

10 This was similarly prepared, as described in example 1, except the starting materials were 3- (l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and ø-methoxyaniline. Yield (90%), analysed for C ₂₀ H ₁₈ ClNO ₂ ; calcd C 70.68 H 5.34 Cl 10.43 N 4.12%, Found C 71.61 H 5.39 Cl 10.38

N 4.19%.

L 5 Example 23

Synthesis of 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid N,N-diisobutylamide of formula 1 where Ri=R ₂ =R ₃ =R- _J =H, R=Cl and R ₃ +R ₆ =N,N-diisobutylamine.

This was similarly prepared, as described in example 1, except the starting materials were 3-(l-chloro-3,4-dihydronapth-2-yl)-acrylic acid and N ₅ N-diisobutylamine. Yield (94%), ^> 0 analysed for C ₂₁ H ₂₈ ClNO; calcd C 72.92 H 8.16 Cl 10.25 N 4.05%, found C 73.88 H 8.21 Cl 10.30 N 4.14%.

Example 24

Synthesis of 3-(l-bromo-3, 4-dihydronapth-2-yl)-acrylic acid piperidide of formula 1 15 where R=Br and Rg+R ₆ =piperidine.

1) Preparation of l-bromo-2-formyl-3,4-dihydronaphthalene

Dry DMF (8.02 ml, 103.2 mmol) in dry dichloromethane (DCM) (50 ml) was cooled to 0° C and phosphorus tribromide (8.0 ml, 89.5 mmol) was added drop-wise. The mixture was stirred at 0° C for 1 hr during which time a pale yellow suspension was formed. A solution 0 of -tetralone (5,03g, 34.4 mmol) in dry DCM (90 ml) was added and the mixture was heated under reflux for 1 hr. After cooling to 0 ⁰ C, aqueous NaHCO3 was added slowly until the

effervescence had subsided. Extraction of the reaction mixture with DCM (3x100ml) was followed by drying the organic layer (MgSO4). The solution was filtered through a celite plug and evaporation of the excess solvent resulted into brown oil. Column chromatography eluting with ethyl acetate :hexane (20:80) gave the product as a brown solid l-bromo-2- formyl-3,4-dihydronaphthalene (6.7Og, 80%), analysed for CnH ₉ BrO; calcd C 55.72 H 3.83 Br 33.70%, found C 56.69 H 3.89 Br 33.77%. ¹ H NMR (CDCl ₃ ): 2.61 (2H, t, J=8 ^' .l Hz) ₅ 3.95 (2H ₅ 1, J-8.1 Hz) ₅ 7.28 (3H ₅ m), 7.89 (IH ₅ d, J=7.2 Hz) ₅ 10.25 (IH ₅ s).

2) Preparation of 3-(l-bromo-3,4-dihydro-napth-2-yl)-acrylic acid

To a mixture of l-bromo-2-formyl-3 ₅ 4-dihydronaphthalene (5.Og ₅ 21 mmol) in pyridine (15 ml) and piperidine (2.5 ml), malonic acid (2.63g ₅ 1.2 eq) was added and kept the reaction mixture at room temperature for 52 hrs. Later the reaction mixture was heated on water bath for 6 hrs, and poured the contents in to a conical flask. To this 50% aqueous HCl solution was added to precipitate the 3-(l-bromo-3,4-dihydro-napth-2-yl)-acrylic acid. This precipitate was filtered and crystallized in pet. ether/ethyl acetate to yield pure product 3 (5.56g, 95%), analysed for C ₁₃ H _n BrO ₂ ; calcd C 55.94 H 3.97 Br 28.68%, found C 56.77 H

4.02 Br 28.72%. ¹ H NMR (CDCl ₃ ): δ 2.61 (2H ₅ 1, 8.2 Hz) ₅ 2.80 (2H ₅ 1, J=8,2 Hz), 6.13 (IH ₅ d, J=15.7 Hz), 7.32 (3H, m), 7.78 (IH, d, J=4.9 Hz) ₅ 8.21 (IH ₅ d, J=I 5.7 Hz).

3) Preparation of 3-(l-bromo-3,4-dihydronapth-2-yI)-acrylic acid piperidide._

To the compound 3-(l-bromo-3 ₅ 4-dihydro-napth-2-yl)-acrylic acid (500mg, 2.31mmol) in dry benzene (15 ml) added freshly distilled thionyl chloride (0.53 ml) and refluxed for lhr, excess of thionyl chloride removed in vacuo and thereafter condensed with dry benzene solution of piperidine (1.0 ml) and stirred for 30 min. The organic layer was washed with water (2x25 ml), dried over anhydrous sodium sulfate, concentrated to give crude product, which was purified on silica gel column using pet. ether: ethyl acetate (92:8) as an eluent to gave the title compound (620mg, 98%), analysed for C ₁₈ H ₂₀ BrNO; calcd C 62.44 H 5.82 Br

23.08 N 4.05%, found C 63.47 H 5.91 Br 23.13 N 4.11%. ¹ H NMR (200 MHz CDCl ₃ ): δ

0.96 (6H ₅ d, J=6.6 Hz ₅ CH (CH ₃ ) ₂ ) ₅ 1.83 (IH, m, CH(CH ₃ ) ₂ ), 2.57 (2H ₅ t, J=7.75

Hz,CH2.CH2) ₅ 2.87 (2H, t, J=7.76 Hz, CH ₂ CH ₂ ), 3.20 (2H, d, J=6.4 Hz, CH ₂ CH), 6.11 (IH ₅ d, J=15.47 Hz, CH=CHCO), 7.21 (3η, m ₅ 3xAr-H), 7.75 (IH, dd, J=2.0, 8.73 Hz, Ar-H), 8í01 (IH, d, J=15.47 Hz, CH=CHCO).

Example 25

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid pyrrolidide of formula 1 where Ri=R ₂ =R ₃ =R ₄ =H, R=Br and R ₅ +R ₆ =pyrrolidine.

This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and pyrrolidine. Yield (90%), analysed for C ₁₇ H ₁₈ BrNO; calcd C 61.46 H 5.46 Br 24.05 N 4.22%, found C 62.41 H 5.49 Br 24.08 N 4.36%.

Example 26 Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid morpholide of formula 1 where R _I =R ₂ =R _J =RJ=H, R=Br and Rs+Rβ =morpholine.

This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and morpholine. Yield (95%), analysed for C ₁₇ Hi ₈ BrNO ₂ ; calcd C 58.63 H 5.21 Br 22.95 N 4.02%, found C 59.41 H 5.29 Br 23.08 N 4.09%

Example 27

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid isobutylamide of formula

1 where This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and isobutylamine. Yield (92%), analysed for Ci ₇ H ₂₀ BrNO; calcd C 61.09 H 6.03 Br 23.91 N 4.79%, found C 61.99 H 6.11 Br 24.02 N 4.83%. ¹ H NMR (CDCl ₃ ): δ 0.95 (6H, d, J=6.66 Hz) ₅ 1.83 (IH, m), 2.57 (2H, t, J=8,2 Hz), 2.87 (2H, t, J=8.2 Hz), 3.21 (2H, d, J=6.60 Hz), 6.11 (IH, d, J=15.5 Hz), 7.21 (3H, m), 7.75 (IH ₃ d, J=4.5 Hz), 8.00 (IH, d, J=15.5 Hz).

Example 28

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid N,N-diisopropyIamide of formula 1 where This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and N,N-diisopropylamine. Yield (92%),

analysed for C ₁₉ H ₂₄ BrNO; calcd C 62.99 H 6.68 Br 22.05 N 3.87%, found C 63.44 H 6.71 Br 22.09 N 3.91%.

Example 29 Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acryIic acid n-butylamide of formula 1 where

This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and n-butyl amine. Yield (86%), analysed for C ₁₇ H ₂₀ BrNO; calcd C 61.09 H 6.03 Br 23.96 N 4.19%, found C 61.97 H 6.11 Br 24.04 N 4.24%.

Example 30

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acryIic acid N-methylpiperizide of formula 1 where Ri=R ₂ =Ra=Ri=H, R=Br and Rs+R ₆ =N-methyIpiperazine. This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and N-methylpiperizine. Yield (86%), analysed for C ₁₈ H ₂ iBrN ₂ O; calcd C 59.84 H 5.86 Br 22.12 N 7.755, found C 60.77 H 5.91 Br 22.19 N 7.84%.

Example 31

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid N,N-diethylamide of formula 1 where Ri=R ₂ =Ra=Ri=H, R=Br and R ₃ +R(i=N,N-diethylamine

This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3 _! 4-dihydronapth-2-yl)-acrylic acid and N,N-diethylamine. Yield (86%), analysed for C ₁₇ H ₂₀ BrNO; calcd C 61.09 H 6.03 Br 23.91 N 4.19%, found C 61.97 H 6,14 Br 24.01 N 4.24%.

Example 32

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid immidozolide of formula 1 where R=CH ₂ -Ph and R ₅ +R ₆ =immidazole.

This was' similarly prepared, as described in example 24, except the starting materials were

3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and immidazole Yield (81%), analysed for Ci ₆ H ₁₇ BrN ₂ O; calcd C 57.67 H 5.14 Br 23.98 N 8.41 %, found C 57.93 H 5.19 Br 24.04 N 8.49%.

Example 33

Synthesis of 3-(l-bromo-3,4-dihydronapth-2-yl)-acryIic acid /?-hydroxypiperizide of formula 1 where

This was similarly prepared, as described in example 24, except the starting materials were 3-(l-bromo-3,4-dihydronapth-2-yl)-acrylic acid and /?-hydroxypiperidine. Yield (90%), analysed for Ci ₈ H ₂₀ BrNO ₂ ; calcd C 59.68 H 5.56 Br 22.06 N 3.87%, found C 61.81 H 5.61 Br 22.1 I N 3.93%.

Example 34

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid isobutylamide of formula 1 where Ri=R ₂ =R ₃ =Ri=H, R=H and R ₅ +R ₆ =isobutylamine. 1) Preparation of 1,2,3,4-tetrahydronaphth-l-oL

To a chilled solution of α-tetralone (7.6g, 52 mmol) in methanol (100 ml), sodium borohydride (500 mg) was added in 2 hour maintaining temperature 0-5 ⁰ C and after the completion of the reaction (monitored by TLC), the volume of the contents was reduced to one fifth, diluted with ice cold water (120 ml) and extracted with ether, the organic layer was washed with water and dried over anhydrous sodium sulfate, concentrated on a rotavapour under reduced pressure to give a colourless viscous oily compound 1,2,3,4- tetrahydronaphth-1-ol (7.1g, 93 %). Analysed for Ci ₀ Hi ₂ O; calcd C 81.01 H 8.16%, found C 82.11 H 8.21 %. 2) Preparation of 2-formyl-3,4-dihydronaphthalene.

To a chilled solution of 1,2,3,4-tetrahydronaρhth-l-ol (7g, 47.3 mmol) in dry DMF (25.0 ml), POCl ₃ (15.0 ml) was added drop wise at 0-5 ⁰ C for lhr and the resulting mixture was stirred at room temperature for 24 hrs. The reaction mixture was poured into ice-cold water (150 ml) and pH maintained by adding 0.5N NaOH solution and the reaction mixture extracted with ethyl acetate (3x100 ml). The combined organic layer washed with water (3x30 ml), dried over anhydrous sodium sulfate and evaporated on rotavapour to give crude

product, which was purified on silica gel column using pet. ether 60-80 ⁰ C as an eluent to gave pale yellow compound 2-formyl-3,4-dihydronaphthalene (7.2 g, 96 %), analysed for C _n Hi ₀ O; calcd C 83.53 H 6.37%, found C 84.44 H 6.41%.

3) Preparation of 3-(3,4-dihydronaphth-2-yI)-acrylic acid

5 To a mixture of 2-formyl-3,4-dihydronaphthalene (7.Og, 49.3 mmol) in pyridine (20 ml) and piperidine (3 nil), malonic acid (9.2 g 1.2 eq) was added and the reaction mixture kept at room, temperature for 52 hrs and then heated on water bath for 6 hrs. The contents were acidified with 50% HCl solution and the resulting precipitate filtered, washed with water and crystallized in pet. ether: ethyl acetate to yield pure product 3-(3,4-dihydronaphth-2-yl)- LO acrylic acid (9.1g. 93 %), analysed for Ci ₃ H ₁₂ O ₂ ; calcd C 77.98 H 6.04%, found C 78.76 H 6.11%. ¹ H NMR (200 MHz CDCl ₃ ): δ 2.92 (2H, t, J=Hz, CH ₂ CH ₂ ), 2.52 (2H, t, J=Hz, CH ₂ CH ₂ ), 6.00 (IH, d, J=Hz, CH=CHCO), 6.81 (IH ₃ S, CH=C), 7.78 (4H, m, 4xAr-H), 8.21 (IH, d, J=Hz, CH=CHCO).

4) Preparation of 3-(3,4-dihydronapth-2-yI)-acryIic acid isobutylamide..

5 To the compound 3-(3,4-dihydronaphth-2-yl)-acrylic acid (200mg, 1 mmol) in dry benzene (20 ml) added freshly distilled thionyl chloride (1.0 ml) and refluxed for lhr, excess of thionyl chloride removed in vacuo and thereafter condensed with dry benzene solution of isobutyl amine (1.0 ml) and stirred for 30 min. The organic layer was washed with water (2x25 ml), dried over anhydrous sodium sulfate, concentrated to give crude product, which

!0 was purified on silica gel column using pet. ether: ethyl acetate (92:8) as an eluent to gave title compound (210mg, 82%) analysed for Ci ₇ H ₂₀ NO; calcd C 79.96 H 8.29 N 5.49%, found. C 80.84 H 8.33 N 5.55 %. ¹ H NMR (200 MHz CDCl ₃ ): δ 0.94 (6H, d, J=6.70 Hz, CH(CH ₃ ) ₂ ), 1.81 (1η, m, Cη(Cη ₃ ) ₂ ), 2.43 (2H, t, J=8.0 Hz, CH2CH ₂ ), 2.88 (2H, t, J=8.0 Hz ₅ CH2CH ₂ ), 3.20 (2H, d, J=6.5 Hz, CH ₂ CH), 5.96 (IH, d, J=15.32 Hz, CH=CHCO), 6.73

^• 5 (1η, s, CH=C), 7.1 (4H, m, Ar-H) ₅ 7.43 (IH ₅ d, J=I 5.33 Hz, CH=CHCO).

Example 35

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid N,N-diisopropylamide of formula

1 where iO This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and N,N-diisopropylamine. Yield (94%), analysed for

Ci ₉ H ₂₅ NO; calcd C 80.52 H 8.89 N 4.90%, found. C 81.43 H 8.93 N 4.97 %.

Example 36

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid piperidide of formula 1 where 5 and R ₅ +R6=piperidide.

This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and piperidine. Yield (84%), analysed for C ₁₈ H _2I NO; calcd C 80.86 H 7.92 N 5.24%, found C 81. ^" 77 H 7.99 N 5.28 %. ¹ H NMR (200 MHz CDCl ₃ ): δ 1.63 (6H, bs, 3xCH2), 2.51 (2H, t, J=8.0 Hz, CH2CH ₂ ), 2.86 (2H, t, J=8.0 Hz, 0 CH2CH ₂ ), 3.55 (4H, m, 2xCH ₂ ), 671 (IH, d, J=15.32 Hz, CH=CHCO), 7.16 (4H, m, Ar-H), 7.45 (IH, d, J=15.33 Hz, CH=CHCO).

Example 37

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid pyrrolidide of formula 1 where 15 Ri=R ₂ =R ₃ =R ₄ =H, R=H and R ₅ +R ₆ =pyrrolidine.

This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and pyrrolidine. Yield (94%), analysed for Cj ₇ Hi ₉ NO; calcd C 80.86 H 7.56 N 5.53%, found C 81.66 H 7.61 N 5.60%.

:0 Example 38

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid niorpholine of formula 1 where and R ₅ +R ₆ =morpholine.

This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and morpholine. Yield (90%), analysed for 5 C ₁₇ H ₁₉ NO ₂ ;'calcd C 75.81 H 7.11 N 5.20%, found. C 76.77 H 7.18 N 5.27%.

Example 39

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid p-methoxyanilide of formula 1 where R ₁ =R ₂ =R ₃ =R _jI =H, R=H and R ₅ +R ₆ =p-methoxyaniIine.

0 This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and />-methoxyaniline. Yield (90%), analysed for

C ₂₀ Hi ₉ NO ₂ ; calcd C 78.66 H=6.27 N 4.59%, found. C 79.44 H 6.31 N 4.62%.

Example 40

Synthesis of 3-(3, 4-dihydronaphth-2-yl)-acrylic acid w-octylamide of formula 1 where

This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and 7?-octylamine. Yield (90%), analysed for C ₂₁ H ₂₉ NO; _, calcd C 80.98 H 9.38 N 4.50% found. C 81.99 H 9.43 N 4.58%.

Example 41

Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid N,N-diethylamide of formula 1 where R ₁ =R ₂ =R ₃ =R ₄ =H, R=H and R _s +R ₆ =N,N-diethylamine.

This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and N.N-diethylamine. Yield (90%), analysed for C _n H ₂₁ NO; calcd C 79.96 H 8.29 N 5.49% found.C 80.77 H 8.33 N 5.54%.

Example 42

Synthesis of 3~(3,4-dihydronaphth-2-yl)-acrylic acid anilide of formula 1 where

R ₂ =R ₃ =Ri=H, R=H and R _s +R6=aniline. This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronapth-2-yl)-acrylic acid and aniline. Yield (90%), analysed for C ₁₉ H ₁₇ NO; calcd C 82.88 H 6.22 N 5.09%, found C 83.77 H 6.27 N 5.18%.

Example 43 Synthesis of 3-(3,4-dihydronaphth-2-yl)-acrylic acid 3,4-methelenedioxy anilide of formula 1 where and R ₅ +R<;=3,4-methyIenedioxy aniline.

This was similarly prepared, as described in example 34, except the starting materials were 3-(3,4-dihydronaρth-2-yl)-acrylic acid and 3,4-methylenedioxy aniline. Yield (90%), analysed for C ₂₀ Hi ₇ NO ₃ ; calcd C 75.22 H 5.37 N 4.39%, found C 76.11 H 5.42 N 4.44%.

Example 44

Synthesis of 3-(l-benzyl-3,4-dihydronaphth-2-yl)-acrylic acid λi-octylamide of formula

1 where Ri=R ₂ =R ₃ =R ₄ =H, R=CH ₂ -Ph and R ₅ +R ₆ =«-octyIamine

1) Preparation of l-(benzyl)-tetrahydro-naphth-l-ol.

To an ethereal solution of Grignard reagent prepared from magnesium metal and benzyl bromide was added α-tetralone (15.Og, lOOmmol) in one hour and then the reaction mixture worked up by pouring . the contents intol% aqueous ammonium chloride solution, the organic layer separated and the aqueous layer extracted with solvent ether (4x100 ml), the combined Organic layer washed with water (3x20 ml), dried over anhydrous sodium sulphate, concentrated to give the title compound yield (17.5g, 70%),- analysed for Ci ₇ HIsO; calcd C 85.67 H 7.61%, found C 85.95 H 7.69%.

2) Preparation of l-benzyl-2-formyI-3,4-dihydronaphthalene.

To a chilled solution of l-(benzyl)-tetrahydro-naphth-l-ol (1Og, 42 mmol) in dry DMF (35 ml), POCl ₃ (16.2 ml) was added drop wise at 0-5 ⁰ C for one hr and the resulting mixture was • stirred at room temperature for 45 hrs. The reaction mixture was poured into ice-cold water (250 ml) containing sodium acetate (15 g). The contents were extracted with ethyl acetate (3x100 ml). The combined extracts were pooled and washed with water (3x50 ml), dried over anhydrous sodium sulfate and concentrated on rotavapour to give crude product, which was purified on silica gel column using pet.ether 60-80 ⁰ C: ethyl acetate (90:10) as an eluent to gave yellow oily liquid compound l-benzyl-2-formyl-3, 4-dihydronaphthalene - (9.1g, 86%), analysed for Ci ₈ H ₁₆ O; calcd C 87.06 H 6.49%, found C 87.47 H 6.59%.

3) Preparation of 3-(l-benzyl-3, 4-dihydronaphth-2-yl)-acrylic acid.

To a mixture of l-benzyl-2-formyl-3, 4-dihydronaphthalene (8.5g, 32.7 mmol) in pyridine (25 ml) and piperidine (5.0 ml), malonic acid (I4.25g, 1.2 eq) was added and kept the reaction mixture at room temperature for 72 hrs. Later the reaction mixture was heated on water bath for 6 hrs, and poured the contents in to a conical flask. To this 50% aqueous HCl solution was added to precipitate the compound 3-(l-benzyl-3, 4-dihydronaρhth-2-yl)- acrylic acid. The precipitates were filtered and crystallized in pet. ether/ethyl acetate to yield pure 3-(l-benzyl-3, 4-dihydronaρhth-2-yl)-acrylic acid (7.5g, 78%), analysed for C ₂ OHi ₈ O ₂ ; calcd C 82.73 H 6.25%, found C 82.98 H 6.32%.

4) Preparation of 3-(l-benzyl-3,4-dihydronaphth-2-yl)-acrylic acid w-octyl amide.

To the compound 3-(l-benzyl-3, 4-dihydronaphth-2-yl)-acrylic acid (500mg, 2.01mmol) _. in dry benzene (20 ml) added freshly distilled thionyl chloride (1.0 ml) and refluxed for one hr, excess of thionyl chloride removed in vacuo and thereafter condensed with dry benzene solution of o.ctylamine (1.0 ml) and stirred for 30 min. The organic layer washed with water (2x25ml), dried over anhydrous sodium sulfate and evaporated on rotary evaporator to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C: ethyl acetate (85:15) as an eluent to gave title compound (620mg, 76%), analysed for C ₂₈ H ₃₅ NO; calcd C 83.74 H 8.78 N 3.49%, found C 84.02 H 8.84 N 3.56%. ' ^{* ■}

Example 45

Synthesis of 3-(l-benzyl-3,4-dihydronaphth-2-yl)-acrylic acid piperidide of formula 1 where Ri=R ₂ =R ₃ =Ri =H, R=CH ₂ -Ph and R ₅ +R ₆ =piperidine. This was similarly prepared, as described in example 44, except the starting materials were 3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid and piperidine. Yield (88%), analysed for C ₂₅ H ₂₇ NO; calcd C 83.99 H 7.61 N 3.92%, found C 84.61 H 7.70 N 4.40%:

Example 46

Synthesis of 3-(l-benzyl-3,4-dihydronaphth-2-yl)-acrylic acid pyrrolidine of formula 1 WhCrB R ₁ =R ₂ =R ₃ =R ₄ =H, R=CH ₂ -Ph and R ₅ +R ₆ =pyrrolidine.

This was similarly prepared, as described in example 44, except the starting materials were 3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid and pyrrolidine. Yield (88%), analysed for C ₂₄ H ₂₅ NO; calcd C 83.93 H 7.34 N 4.08%, found C 84.41 H 7.40 N 4.11%.

Example 47

Synthesis of 3-(l-benzyl-3,4-dihydronaphth-2-yl)-acrylic acid morpholide of formula 1 where R ₁ =R ₂ =R ₃ =Rj=H, R=CH ₂ -Ph and R ₅ +R ₆ =morpholine.

This was similarly prepared, as described in example 44, except the starting materials were 3-(l-benzyl-3,4-dihydiOnapth-2-yl)-acrylic acid and morpholine. Yield (79%), analysed for C ₂₄ H ₂₅ NO ₂ ; calcd C 80.19 H 7.01 N 3.90%, found C 80.91 H 7.08 N 3.98%.

Example 48

Synthesis of 3-(l-benzyl-3,4-dihydronaphth-2-yl)-acrylic acid isobutylamide of formula

1 where

This was similarly prepared, as described in example 44, except the starting materials were 5 3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid and isobutylamine. Yield (92%), analysed for C ₂₄ H ₂₇ NO; calcd C 83.44 H 7.88 N 4.05%, found C 83.91 H 7.92 N 4.11%.

Example 49

Synthesis of 3-(l-benzyI-3,4-dihydronaphth-2-yI)-acrylic N,N-diisopropyIamide of 10 formula 1 where

This was similarly prepared, as described in example 44, except the starting materials were 3-(i-benzyl-3,4-dihydronapth-2-yl)-acrylic acid and N,N-diisopropylamine. Yield (82%), analysed for C ₂₆ H ₃ iNO; calcd C 83.60 H 8.37 N 3.75%, found C 83.99 H 8.42 N 3.80%.

15 Example 50

Synthesis of 3-(l-benzyl-3,4-dihydronaphth-2-yl)~acrylicacid /j-hydroxy piperidine of formula 1 where piperidine

This was similarly prepared, as described in example 44, except the starting materials were 3-(l-benzyl-3,4-dihydronapth-2-yl)-acrylic acid and /?-hydroxypiperidine. Yield (72%), >0 analysed for C ₂₅ H ₃₇ NO ₂ ; calcd C 80.40 H 7.29 N 3.75%, found C 80.69 H 7.32 N 3.80%.

Example 51

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid piperidide of formula 1 where R ₁ =R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and R _g +R ₆ ==piperidine. '.5 1) Preparation of 4~allyl-i,2-dimethoxy benzene.

A solution comprising of methyl eugeonol (1Og, 60.97 mmol) and CH ₃ I (9 ml) in dry acetone (50. ml) was refluxed at 60 C for 24 hrs. The reaction mixture volume was reduced to one fourth on rotavapour, contents cooled and diluted with water (150 ml), extracted with ethyl acetate (3x100 ml). The combined organic layer washed with water (3x30 ml), dried 0 over anhydrous sodium sulfate and evaporated on rotavapour to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C as an eluent to gave compound

4-allyl-l,2-dimethoxy benzene (9.3g, 85 %), analysed for C _n Hi ₄ O ₂ ; calcd C 74.13 H 7.92%, found C 75.03 H 7.99%.

2) Preparation of 6,7-dimethoxy-2-formyl-3,4-dihydro-naphthalene

To a chilled solution of 4-allyl-l,2-dimethoxy benzene (9.Og, 50.96 mmol) in dry DMF (15 ml), POCl ₃ (13 ml) was added drop wise at 0-5 ⁰ C for 1 hr and the resulting mixture was stirred at room temperature for 72-90 hrs. The reaction mixture was poured into ice-cold water (150 ml) and pH 7.0 attained by adding IN NaOH solution ^' and the reaction mixture extracted with ethyl acetate (5x100 nil). The combined organic layer washed with water (3x30 ml), dried over anhydrous sodium sulfate and evaporated on rotavapour to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C: ethyl acetate (80:20) ^" as an eluent to gave compound 6,7-dimethoxy-2-formyl-3,4-dihydro-naphthalene (3.2g, 29%), analysed for C ₁₃ Hi ₄ O ₃ ; calcd C 71.54 H 6.67%, found C 72.44 H 6.71%. ¹ H NMR (CDCl ₃ ): δ 2.55 (2H, t, J=8.3 Hz), 2.82 (2H, t, J=8.3 Hz), 3.91 (6H, m), 6,74 (IH, s), 6.81 (IH, s), 7.20 (IH, s). 3) Preparation of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-acrylic acid.

To a stirring solution of ylide (11.5g) (prepared from triphenylphospine and ethyl bromoacetate) containing sodium hydride (1.Og) was added benzene solution of 6,7- dimethoxy-3,4-dihydro-naphthalene-2-carbaldehyde (5.5g, 25 mmol) and after 24 hours an additional amount of sodium hydride (0.5g) was added. The reaction mixture was stirred for 72 hours at 40 ⁰ C. On cooling, the contents were diluted with ethyl acetate (100 ml) to quench unused sodium hydride, then diluted with water (200 ml), organic layer separated and the aqueous layer extracted with ethyl acetate (2x100 ml). The combined organic layer washed with water (2x50 ml) and concentrated under reduced pressure. The crude 3-(6,7- dimethoxy-3,4-dihydro-naphtha-2-yl)-acrylate obtained above was hydrolysed without purification- in 10% methanolic potassium hydroxide solution and after usual work up ,the acid obtained was purified on silica gel column using pet. ether 60-80 ⁰ C: ethyl acetate (75:25) as an eluent to gave compound 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-acrylic acid (5.59g/86%), analysed for Ci ₅ Hi ₆ O ₄ ; calcd C 69.22 H 6.2%, found C 70.12 H 6.27%. ¹ H NMR (CDCl ₃ ): δ 2.49 (2H, t, J=8.20 Hz), 2.84 (2H, t, J=8.20 Hz), 3.86 (6H, m), 5.94 (IH, d, J=15.5 Hz); 6.71 (3H, m), 7.56 (IH, d, j=15.5 Hz). .

4) Preparation of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid piperidide

To the compound 3 -(6, 7-dimethoxy-3,4-dihydronaphth-2-yl)-acrylic acid (lOOmg, 0.384 mmol) in dry benzene (15 ml) added freshly distilled thionyl chloride (1.0 ml) and refluxed for 1 hr, excess of thionyl chloride evaporated in vacuo and thereafter condensed with dry benzene solution of piperidine (1.0 ml) and stirred for 30 min. The organic layer washed with water (2x25 ml), dried over anhydrous sodium sulfate, concentrated to give crude product, which was purified on silica gel column using pet. ether: ethyl acetate (85:15) as an eluent to gave title compound (1 lOmg, 88%) analysed for C _2O H ₂₅ NO ₃ ; calcd C 7337 H 7.70 N 4.28%, found C 74.21 H 7.78 N 4.31%. ¹ HNMR (CDCl ₃ ): δ 1.60 (6H, m), 2.47 (2H, t, J=8.15 Hz), 2.86 (2H, t, J=8.15 Hz), 3.59 (4H, m), 3.87 (6H, m), 6.39 (IH, d, J=15.1 Hz), 6.66 (3H ₃ m), 7.41 (IH, d, J=I 5.1 Hz).

Example 52

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yI)-propenoic acid morpholide of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H, R ₃ +R ₆ =morpholine.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6, 7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and morpholine. Yield (80%), analysed for C ₁₉ H ₂₃ NO ₄ ; calcd C 69.28 H 7.04 N 4.25%, found C 70.11 H 7.10 N 4.31%. ¹ H NMR (CDCl ₃ , δ): 2.47 (2H, t, J=8.2 Hz), 2.82 (2H, t, J=8.2 Hz), 3.71 (8H, m), 3.87 (6H, m), 6.32 (IH, d, J=15.1 Hz), 6.66 (2H, m), 7.11 (IH, d), 7.66 (IH, d, J=15.1 Hz).

Example 53

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid pyrrolidine of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and Rs+Rβ-pyrrolidine. This was also similarly prepared, as described in example 51, except the starting materials was 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and pyrrolidine. Yield (80%), analysed for Ci ₉ H ₂₃ NO ₃ ; calcd C 72.82 H 7.40 N 4.47%, found C 73.77 H 7.48 N 4.51%.

Example 54

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid /i-octylamide of

formula 1 where R ₁ =R ₄ =H, R ₂ =Ra=OCH ₃ , R=H and R ₅ +R<;=w-octylamine.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and n-octylamine. Yield (88%), ^• analysed for C ₂₃ H ₃₃ NO ₃ ; calcd C 74.36 H 8.95 N 3.77%, found C 74.97 H 9.02 N 3.81%. ¹ H NMR (CDCl ₃ ): δ 0.88 (3H ₅ 1, J=63 Hz), 1.24 (1OH, m), 1.54 (2H, m), 2.42 (2H, t, J= 8.2 Hz), 2.82 (2H, t, J=8.2 Hz), 3.35 (2H, t, J=6.30 Hz), 5.90 (IH, d, J=15.2 Hz), 6.65 (2H, m), 7.09 (IH, d), 7.41 (IH, d, J=I 5.23 Hz).

Example 55 Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid isobutylamide of formula 1 where isobutylamine.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and isobutylamine. Yield (90%), analysed for Ci ₉ H ₂₅ NO ₃ ; calcd C 72.35 H 7.99 N 4.44%, found C 72.99 H 8.08 N 4.49%. ¹ H NMR (CDCl ₃ ): δ 0.96 (6H, m), 1.83 (IH, m), 2.44 (2H, t, J=8.3 Hz), 2.77 (2H, t, J=8.3 Hz), 3.23 (2H, t, J=6.5 Hz), 5.90 (IH, d, J=I 5.3 Hz), 6.67 (2H, m), 7.12 (IH, d), 7.68 (IH, d, J=I 5.3 Hz).

Example 56 Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid /irbutylamide of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and R ₃ +R ₆ =n-butylamine.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-piOpenoic acid and π-butylamine. Yield (80%), analysed for Ci ₉ H ₂₅ NO ₃ ; calcd C 72.35 H 7.99 N 4.44%, found C 73.11 H 8.06 N 4.51%.

Example 57

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid λϊ-propylamide of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and R ₅ +R6=«-propylamine.

This w.as similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yI)-piOpenoic acid and ^-propylamine. Yield (80%), analysed for Ci ₈ H ₂₃ NO ₃ ; calcd C 71.73 H 7.69 N 4.65%, found C 72.44 H 7.75 N 4.70%.

Example 58

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid isopropylamide of formula 1 where Ri=R ₄ =H, R ₂ =Rs=OCH ₃ , R=H and R ₅ +R ₆ = iopropylamine.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and isopropyl amine. Yield (80%), analysed for C ₁₈ H ₂₃ NO ₃ ; calcd C 71.73 H 7.69 N 4.65%, found C 72.45 H 7.74 N 4.71%.

Example 59 Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid N,N- diisopropylamide of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and R ₅ H-Re= N,N- diisopropylamine.

This was similarly prepared, as described in example 51, except the starting materials are 3- (6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and N,N-diisopropylamine. Yield (85%), analysed for C ₂₁ H ₂₉ NO ₃ ; calcd C 73.44 H 8.51 N 4.08%, found C 74.11 H 8.59 N 4.14%.

Example 60

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid anilide of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and R ₅ +R<;=aniline.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and aniline. Yield (85%), analysed for C ₂ iH ₂ iNO ₃ ; calcd C 75.20 H 6.31 N 4.18%, found C 76.11 H 6.39 N 4.24%.

Example 61

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid o-methyl anilide of formula 1 where Ri=R ₄ =H, R ₂ =R ₃ =OCH ₃ , R=H and R ₅ +R6=ø-methyl aniline.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and ø-methyl aniline. Yield (89%), ^' analysed for C ₂₂ H ₂₃ NO ₃ ; calcd C 76.62 H 6.63 N 4.01%, found C 77.23 H 6.71 N 4.09%.

Example 62

Synthesis of 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid p-methyl anilide of formula 1 where R=H and aniline.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and p-methyl aniline. Yield (72%), analysed for C ₂₂ H ₂₃ NO ₃ ; calcd C 76.62 H 6.63 N 4.01%, found C 77.45 H 6.69 N 4.11%.

Example 63 Synthesis of 3~(6,7-dimethoxy-3,4-dihydronaphth~2-yl)- propenoic acid /?-methoxy anilide of formula 1 where R=H and aniline.

This was similarly prepared, as described in example 51, except the starting materials are 3-(6,7-dimethoxy-3,4-dihydronaphth-2-yl)-propenoic acid and j>methoxy aniline. Yield (82%), analysed for C ₂₂ H ₂₃ NO ₄ ; calcd C 72.31 H 6.34 N 3.83%, found C 72.98 H 6.40 N 3.89 %.

Example 64

Synthesis of 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2E,4JE'-pentadi enoic acid- isobutylamide of formula 2 where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl, R ₅ +R<;=isobutenylamine and R ₇ =methyl.

1) Preparation of l-chloro-2-formyl-3,4-dihydronaphthalene

To a chilled solution of α-tetralone (25g, 170 mmol) in dry DMF (15 ml), POCl ₃ (15.75 ml) was added drop wise at 0-5 ⁰ C for one lir. and the resulting mixture was stirred at room temperature for 24 hrs. The reaction mixture was poured into ice-cold water (150 ml) containing sodium acetate (25 g). The reaction mixture was extracted with ethyl acetate (3x200 ml). The combined extracts were washed with water (3x50 ml), dried over anhydrous sodium sulfate and evaporated on rota vapour to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C as an eluent to gave yellow viscous oil compound l-chloro-2-formyl-3,4-dihydronaphthalene (31 g, 95%), analysed for C, ,H ₉ ClO; calcd C 68.58 H 4.71 Cl 18.40%, found C 69.45 H 4.78 Cl 18.46%.

2) Preparation of l-(l-chloro-3,4-dihydronaphth-2-yl)-propan-l-ol.

To an ethereal solution of. Grignard reagent prepared from magnesium metal and ethyl iodide was added compound l-chloro-2-formyl-3,4-dihydronaphthalene (1Og, 52mmol) in one hour and then the reaction mixture worked up by pouring the contents into 1% aqueous ammonium chloride solution, the organic layer separated and the aqueous layer extracted with solvent ether (4x100 ml), the combined organic layer washed with water (3x20 ml), dried over anhydrous sodium sulphate, concentrated to give the. product l-(l-chloro-3,4- dihydronaρhth-2-yl)-propan-l-ol as an viscous oil (7.6g, 66%), analysed for CnHi ₅ ClO; calcd C 70.11 H 6.79 Cl 15.92%, found C 71.55 H 6.84 Cl 15.99%. 3) Preparation of 3-(l-chloro-3,4-dihydronaphth-2-yl)-2-methyl-propenal.

To a chilled solution of l-(l-chloro-3,4-dihydronaphth-2-yl)-propan-l-ol (5g, 22.5 mmol) in dry DMF (25 ml), POCl ₃ (11 ml) was added drop wise at 0-5 ⁰ C for lhr and the resulting mixture was stirred at room temperature for 24 hrs. The reaction mixture was poured into ice-cold water (250 ml) containing sodium acetate (15 g). The contents were extracted with ethyl acetate (3x100 ml). The combined extracts were pooled and washed with water (3x50 ml), dried over anhydrous sodium sulfate and concentrated on rota vapour to give crude product, which was purified on silica gel column using pet. ether 60-80 ⁰ C: ethyl acetate (98:2) as an eluent to gave yellow oily liquid compound 3-(l-chloro-3,4-dmydroriaphth-2- yl)-2-methyl-propenal (4.5g, 86%), analysed for C ₁₄ H ₁₃ ClO; calcd C 72.26 H 5.63 Cl 15.24%, found C 72.97 H 5.69 Cl 15.31%.

4) Preparation of 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2£',4£'-penta dienoic acid.

To a stirring solution of ylide (8.5g) (prepared from triphenylpho spine and ethyl bromoacetate) containing sodium hydride (1.Og) was added benzene solution of 3-(l-chloro- 3,4-dihydronaphth-2-yl)-2-methyl-propenal (3.5 g,15 mmol) and after 24 hours an additional amount of sodium hydride (0.5g) was added. The reaction mixture was stirred for 72 hours at 40 ⁰ C. On cooling the contents were diluted with ethyl acetate (100 ml) to quench unused sodium hydride, and then diluted with water (200 ml), organic layer separated and the aqueous layer extracted with ethyl acetate (2x100 ml). The combined organic layer washed with water (2x50 ml) and concentrated under reduced pressure. The crude 5-(l-chloro-3,4- dihydronapl)th-2-yl)-4-methyl-2E,4E-ρentadienoic acid ester thus obtained was hydrolysed

without purification in 10% methanolic potassium hydroxide solution and after usual work up, the acid obtained was purified on silica gel column using pet. ether 60-80 C: ethyl acetate (75:25) to give 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2£' _s 4£'-pentadienoic acid (3.2g, 80%), analysed for Ci ₆ Hi ₅ ClO ₂ ; calcd C 69.95 H 5.50 Cl 12.90%, found C 70.77 H 5.59 Cl 12.98%.

5) Preparation of 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyI-2E,4E-pentadien oic acid isobutylamide.

To the compound 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2E,4E-pentadien oic acid (500mg, 1.82 mmol) in dry benzene (40 ml) added freshly distilled thionyl chloride (1.5 ml) and refluxed for lhr, excess of thionyl chloride removed in vacuo and thereafter condensed with dry benzene solution of isobutyl amine (1.0 ml) and stirred for 30 min. The organic layer washed with water (2x25 ml), dried over anhydrous sodium sulfate, concentrated to give crude product, which was purified on silica gel column using pet. ether: ethyl acetate (92; 8) as an eluent to give title compound (500mg, 83%), analysed for Ca ₀ H ₂₄ ClNO; calcd C 72.82 H 7.33 Cl 10.75 N 4.25, found C 73.33 H 7.39 Cl 10.81 N 4.30%.

Example 65

Synthesis of 5-(l-chloro-3,4-dihydronaphth-2-yI)-4-methyI-2E,4E-pentadien oic acid N,N-diisopropylamide of formula Ib where Ri=R ₂ =Ra=Ri=H, R=Cl, R ₅ +R _β =N,N- diisopropylamine and R ₇ =methyl.

The title compound was similarly prepared, as described in example 64, except the starting materials are 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2E,4E-pentadien oic acid and N,N-diisppropylamine. Yield (90%), analysed for C ₂₂ H ₂₈ ClNO; calcd C 73.83 H 7.89 Cl 9.91 N 3.91%, found C 74.17 H 7.92 Cl 9.99 N 3.98%.

Example 66

Synthesis of 5-(l-chloro-3,4-dihydronaphth-2-yl)-4-methyl-2JE',4£'-penta dienoic acid piperidide of formula Ib where and

R7=methyl. The title compound was similarly prepared, as described in example 64, except the starting materials are 5-(l-chloro-3,4-dihydro-naρhth-2-yl)-4-methyl-penta-2,4-die noic acid and

piperidine. Yield (82%), analysed for C ₂ iH ₂₄ ClNO; calcd C 73.78 H 7.08 Cl 10.37 N 4.10%, found C 74.11 H 7.11 Cl 3.41 N 4.17%.

Example 67

Synthesis of 5-(l-chloro-3,4-dihydronaphth-2-yI)-4-methyl-22?,42T-pentadi enoic acid pyrrolidide of formula Ib where and

R ₇ -methyl.

The title compound was similarly prepared, as described in example 64, except the starting materials are 5-(l-chloro-3,4-dihydronaphra-2-yl)-4-methyl-penta-22s,4i?- dienoic acid and pyrrolidine. Yield (94%), analysed for C ₂₀ H ₂₂ ClNO; calcd C 73.27 H 6.76 Cl 10.81 N 4.27%, found C 74.12 H 6.71 Cl 10.78 N 4.21%.

Example 68

Synthesis of 5-(l-chloro-3,4-dihydronaphth-2-yI)-4-methyl-2E,4 _J E'-pentadienoic acid morpholide of formula Ib where and

R ₇ =methyl.

The title compound was similarly prepared, as described in example 64, except the starting materials were 5-(l-chloro-3,4-dihydro-naphth-2-yl)-4-methyi-penta-2,4-dien oic acid and morpholine. Yield (90%), analysed for C ₂₀ H ₂₂ ClNO ₂ ; calcd C 69.86 H 6.45 Cl 10.31 N 4.07%, found C 70.12 H 6.49 Cl 10.39 N 4.13%.

Example 69a

Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and other Gram positive bacteria when used in combination with compound of formula Ia where Ri=R ₂ =R ₃ =Ri=H, R=Cl and R _s +R<;=N,N-diisopropyIamine.

Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, using method described in the study design. Sixteen to four fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table Ia).

Example 69b

Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and other Gram positive bacteria when used in combination with compound of formula Ia where R=CI and R ₅ +R<i=N,N-diethyIamine. Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, using method described in the study design. Sixteen to four fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table Ib).

Example 69c

Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and other Gram positive bacteria when used in combination with compound of formula Ia where 4-methylenedioxy-aniline.

Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, using method described in the study design. Four to two fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table Ic).

Example 69d Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and . other Gram positive bacteria when used in combination with compound of formula Ia where Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, using method described in the study design. Sixteen to four fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table Id).

Example 69e

Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and other Gram positive bacteria when used in combination with compound of formula Ia where

Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, using method described in the study design. A two to four fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table Ie).

Example 69f

Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and other Gram positive bacteria when used in combination with compound of formula laa [3- (l-chloro-l^jS^-tetrahydronapth-ϊ-yO-propanoic acid NjN-diisopropylamide]. Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, using method described in the study design. A two fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table If).

Example 69g

Decrease in the MICs of Amikacin against Staphylococcus aureus, MRSA and other Gram positive bacteria when used in combination with compound of formula laa [5- (l-chloro~ϊ,2,3,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid piperidide].

Minimum Inhibitory Concentration (MIC) of Amikacin alone and in combination with the above mentioned potentiator was performed against Staphylococcus aureus species, .using method described in the study design.' A two fold reductions in MIC of Amikacin was observed in combination with the potentiator (Table Ig).

Example 70a Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula Ia where and R ₅ +R ₆ =N,N-diisopropylamine.

Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to two fold reductions in MIC of ciprofloxacin was observed in combination with the potentiator (Table 2a).

Example 70b

Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula Ia where R=CI and R ₅ +R<;=N,N-diethylamine. Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Four to two fold reductions in MIC of ciprofloxacin were observed in combination with the potentiator (Table 2b).

Example 70c

Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula Ia where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl and R ₅ +R ₆ =3,4-methylenedioxyaniline>

Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Two fold reductions in MIC of ciprofloxacin were observed in combination with the potentiator (Table 2c).

Example 7Od Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula Ia where Ri=R ₂ =R ₃ =Ri=H, R=CI, R ₅ +R ₆ =piperidine and R ₇ =methyl.

Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Four to two fold reductions in MIC of ciprofloxacin were observed in combination with the potentiator (Table 2d).

Example 7Oe

Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula Ia where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl and R ₅ +R<;=isobutylamine.

Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to two fold reductions in MIC of ciprofloxacin was observed in combination with the potentiator (Table 2e).

5

Example 7Of

Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula ϊa where

[0 Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to two fold reductions in MIC of ciprofloxacin was observed in combination with the potentiator (Table 2f).

5 Example 7Og

Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA arid other Gram positive bacteria used in combination with compound of formula Ia where

Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with !0 the above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to two fold reductions in MIC of ciprofloxacin was observed in combination with the potentiator (Table 2g).

Example 7Oh

5 Decrease in the MICs of Ciprofloxacin against Staphylococcus aureus, MRSA and other Gram positive bacteria used in combination with compound of formula Ia where R=H and R ₅ +R ₆ =N,N-diisoproρylamine.

Minimum Inhibitory Concentration (MIC) of ciprofloxacin alone and in combination with ■ the above mentioned potentiator was performed against bacterial species, using method 0. described in the study design. Two fold reductions in MIC of ciprofloxacin were observed in combination with the potentiator (Table 2h).

Example 71a

Decrease in the MICs of rifampicin against M.tiiberculosis, M. avium and M. intracellure when used in combination with compound of formula Ia where Minimum Inhibitory Concentration (MIC) of rifampicin alone and in combination with the above mentioned potentiator was performed against Mycobacterial species, using method described in the study design. Four to two fold reductions in MIC of rifampicin was observed in combination with the potentiator (Table 3a).

Example 71b

Decrease in the MICs of rifampicin against M.tuberculosis, M. avium and M. intracellure when used in combination with compound of formula Ia where and R ₅ +R ₆ =N,N-diethyIamine.

Minimum Inhibitory Concentration (MIC) of rifampicin alone and in combination with the above mentioned potentiator was performed against Mycobacterial species, using method described in the study design. Four to two fold reductions in MIC of rifampicin was observed in combination with the potentiator (Table 3 b).

Example 71c Decrease in the MICs of rifampicin against M.tuberculosis, M. avium and M. intracellure when used in combination with compound of formula Ia where R=Br and R ₅ +R<;=isobutylamine.

Minimum Inhibitory Concentration (MIC) of rifampicin alone and in combination with the above mentioned potentiator was performed against Mycobacterial species _> using method described in the study design. Eight to four fold reductions in MIC of rifampicin was observed in combination with the potentiator (Table 3c).

Example 71 d

Decrease in the MICs of rifampicin against M.tuberculosis, M. avium and M. intracellure when used in combination with compound of formula Ia where R ₁ =R ₂ =R ₃ =Ri=H, R=H and R ₅ +R ₆ =N,N-diisopropylamine.

Minimum Inhibitory Concentration (MIC) of rifampicin alone and in combination with the above mentioned potentiator was performed against Mycobacterial species, using method described in the study design. Four to two fold reductions in MIC of rifampicin was observed in combination with the potentiator (Table 3d). • ^{■ ' ' '}

Example 72a

Decrease in the MICs of mupirocin against Staphylococcus aureus, and MRSA used in combination with compound of formula Ia where Rx=R ₂ =Rs=Ri=H, R=Cl and R5+R ₆ =N,N-diisopropylamine. Minimum Inhibitory Concentration (MIC) of mupirocin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to two fold reductions in MIC of mupirocin was observed in combination with the potentiator (Table 4a).

Example 72b

Decrease in the MICs of mupirocin against Staphylococcus aureus, and MRSA isolates used in combination with compound of formula Ia where R ₁ =R ₂ =Rs-Ri -H, R=Cl and Rs+R ₆ =N,N-diethyIamine.

Minimum Inhibitory Concentration (MIC) of mupirocin. alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to foμr fold reductions in MIC of mupirocin was observed in combination with the potentiator (Table 4b).

Example 72c Decrease in the MICs of mupirocin against Staphylococcus aureus, and MRSA used in combination with compound of formula Ia where and Rs+R ₆ =3,4-methylenedioxy-aniline.

Minimum Inhibitory Concentration (MIC) of mupirocin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. A two fold reduction in MIC of mupirocin was observed in combination with the potentiator (Table 4c).

Example 72d

Decrease in the MICs of mupirocin against Staphylococcus aureus, and MRSA isolates used in combination with compound of formula Ib where R=CI,

5 Minimum Inhibitory Concentration (MIC) of mupirocin alone and in combination with the above mentioned potentiator was performed against bacterial species, using method described in the study design. Four to two fold reductions in MIC of mupirocin was observed in combination with the potentiator (Table 4d).

10 Example 72e

Decrease in the MICs of mupirocin against Staphylococcus aureus, and MRSA isolates used in combination with compound of formula Ia where Ri=R ₂ =Rs=Ri=H, R=Br and

Minimum Inhibitory Concentration (MIC) of mupirocin alone and in combination with the 15 above mentioned potentiator was performed against bacterial species, using method described in the study design. Eight to two fold reductions in MIC of mupirocin was observed in combination with, the potentiator (Table 4e).

Example 72f

'.0 Decrease in the MICs of mupirocin against Staphylococcus aureus, and MRSA used in combination with compound of formula Ia where and Rs+R<;=N,N-diisopropyϊamine.

Minimum Inhibitory Concentration (MIC) of mupirocin alone and in combination with the above mentioned potentiator was performed against bacterial species, Using method ,5 described in the study design. A two fold reduction in MIC of mupirocin was observed in combination with the potentiator (Table 4f).

Example 73a

Reduction in the dose requirement of Ciprofloxacin when used in combination with 0 compound of formula Ia where diisopropylamine in systemic infection model of mice.

The study was conducted to see the in vivo response of ciprofloxacin in combination with the above mentioned potentiator. The Swiss albino mice were infected intravenously with Staphylococcus aureus ATCC 29213 (10 ⁷ CFU/mouse). The infected mice were divided in groups and each group consisted of 6 mice. The treatment consisted of one dose immediately after the infection followed by the next dose after a gap of 6 hrs. The result was recorded as number of survivals each day. The mice were observed for seven days and ED ₅₀ was determined after seven days of observation. The ED ₅₀ for ciprofloxacin was 9.2 mg/kg and in combination with the potentiator the ED ₅₀ for ciprofloxacin was reduced to 5.86 mg/kg.

Example 73b

Reduction in the dose requirement of Ciprofloxacin when used in combination with compound of formula Ia where and R ₅ +R<;=isobutylamine in systemic infection model of mice. The study was conducted to see the in vivo response of ciprofloxacin in combination with the above mentioned potentiator. The Swiss albino mice were infected intravenously with Staphylococcus aureus ATCC 29213 (10 ⁷ CFU/mouse). The infected mice were divided in groups and each group consisted of 6 mice. The treatment consisted of one dose immediately after the infection followed by the next dose after a gap of 6 hrs. The result was recorded as number of survivals each day. The mice were observed for seven days and ED ₅₀ was determined after seven days of observation. The ED ₅₀ for ciprofloxacin was 9.2 mg/kg and in combination with the potentiator the ED ₅₀ for ciprofloxacin was reduced to 4.96 mg/kg.

Example 73c

Reduction in the dose requirement of Ciprofloxacin when used in combination with compound of formula Ia where diisopropylamine in systemic infection model of mice.

The study was conducted to see the in vivo response of ciprofloxacin in combination with the above mentioned potentiator. The Swiss albino mice were infected intravenously with

Staphylococcus aureus ATCC 29213 (10 ⁷ CFU/mouse). The infected mice were divided in

groups and each group consisted of 6 mice. The treatment consisted of one dose immediately after the infection followed by the next dose after a gap of 6 hrs. The result was recorded as number of survivals each day. The mice were observed for seven days and ED50 was determined after seven days of observation. The ED ₅₀ for ciprofloxacin was 9.2

Y

5 mg/kg and in combination with the potentiator the ED ₅₀ for ciprofloxacin was reduced to 7.86 mg/kg.

Example 74

Reduction in the dose requirement of Mupirocin when used in combination with 10 compound of formula Ia where diisopropylamine.

The study was conducted to see the in vivo response of Mupirocin in combination with the above mentioned potentiator. Wound area of 1.5 cm X 1.5 cm was created on the skin of mice by abrasion with sand paper. An inoculum of 10 ⁸ CFU/ml of MRSA was applied on to 15 this wound area. The wound was treated for five days (two applications a day) with mupirocin cream and the other group with a formulation of mupirocin at l/4 ⁿ concentration and compound of formula Ia. The combination of mupirocin with compound of formula Ia showed better wound healing (Table 5).

>0 Example 75

Increased accumulation and decreased efflux of ethidium bromide by compound of formula Ia where Ri=R ₂ =R ₃ =R _t =H, R=Cl and R ₅ +R ₆ =N,N-diisopropylamine in Staphylococcus aureus (wild type) and Ciprofloxacin mutant (Cip ^R )

Measurement of the level of ethidium bromide accumulation and efflux in S. aureus ATCC

'.5 29213 (wild strain) and strain CIP ^r -l (ciprofloxacin-selected mutant) was based on a previously described method (Brenwald et.al, Antimicrobial Agents and Chemotherapy

1998; 42(8): 2032-2035). Briefly, for measurement of the level of accumulation, both the bacterial strains were grown overnight on Trypticase Soya Agar. Bacterial suspensions were prepared at an optical density at 550 nm of 0.2 in uptake buffer (NaCl, 110 mM; KCl, 7

0 mM; NH4C1, 50 mM; Na2HPO4, 0.4 mM; Tris base, 52 mM; glucose, 0.2% adjusted to pH

7.5 with HCl) and were then exposed to ethidium bromide at a concentration of 2μg/ml. The

increase in fluorescence as ethidium bromide entered the cells was recorded fluorometrically with a Perkin-Elmer model LS50 spectrofluorimeter (excitation λ, 530 nm; emission, 600 nm) at 30 ⁰ C. The effect of compound of formula Ia where 3-(l-chloro-3,4-dihydronapth-2- yl)-acrylic acid N,N-diisopropylamide on the level of accumulation was determined in a similar way, except that compound of formula Ia was added to the uptake buffer at a concentration of 25 μg/ml (Figure IB).

For determining ethidium bromide loss, bacterial suspensions were prepared as described above and were exposed to ethidium bromide (2 μg/ml) in the presence of compound of formula 1 (25μg/ml) for 30 min at 37 ⁰ C. The cells were then pelleted by centrifugation and were re-suspended in fresh uptake buffer. The loss of ethidium bromide from the cells was measured as a decrease in fluorescence (Figure IB).

Table Ia. MICs of Amikacin alone and in combination with compound of formula Ia where and R ₅ +R ₆ =N,N-diisopropylamine. (Figures in bold face show reduction in MIC).

Table Ib. MICs of Amikacin alone and in combination with compound of formula Ia where Ri=R ₂ =R ₃ =Ri=H, R=Cl and R ₅ +R<;=N,N-diethylamine. (Figures in bold face show reduction in MIC)

Table Ic. MICs of Amikacin alone and in combination with compound of formula Ia where (Figures in bold face show reduction in MIC)

Table Id. MICs of Amikacin alone and in combination with compound of formula Ia where Ri=R ₂ =Rs=Ri=H, R=Br and Rs+R^isobutylamine. (Figures in bold face show reduction in MIC)

Table Ie. MICs of Amikacin alone and in combination with compound of formula Ia where (Figures in bold face show reduction in MIC)

Table If. MICs of Amikacin alone and in combination with compound of 3-(l-chloro- l,2,3,4-tetrahydronapth-2-yl)-propanoic acid N,N-diisopropylamide. (Figures in bold face show reduction in MIC

Table Ig. MICs of Amikacin alone and in combination with compound of 5-(l-chloro- l,2,3,4-tetrohydronaphth-2-yl)-4-methyl-pentanoic acid piperidide. (Figures in bold face show reduction in MIC)

Table 2a. MICs of Ciprofloxacin alone and in combination with compound of formula [0 Ia where (Figures in bold face show reduction in MIC)

Table 2b. MICs of Ciprofloxacin alone and in combination with compound of formula Ia where =H, R=Cl and R ₅ +R6=N,N-diethylamine. (Figures in bold face show reduction in MIC)

Table 2c. MICs of Ciprofloxacin alone and in combination with compound of formula Ia where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl and R ₅ +R ₆ =3,4-methylenedioxy-aniline. (Figures in bold face show reduction in MIC)

Table 2d. MICs of Ciprofloxacin alone and in combination with compound of formula Ib where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl, R ₅ -HR<;=piperidine and R ₇ =methyl. (Figures in bold face show reduction in MIC)

Table 2e. MICs of Ciprofloxacin alone and in combination with compound of formula Ia where R ₁ =R ₂ =R ₃ =R4 =H, R=Cl and R5+R6=isobutylamine. (Figures in bold face show reduction in MIC)

Table 2f. MICs of Ciprofloxacin alone and in combination with compound of formula Ia where and Rs+R ₆ =isobutylamine. (Figures in bold face show reduction in MIC)

Table 2g. MICs of Ciprofloxacin alone and in combination with compound of formula Ia where R=Br and (Figures in bold face show reduction in MIC)

Table 2h. MICs of Ciprofloxacin alone and in combination with compound of formula Ia λvhere R=H and R ₅ +R ₆ =N,N-diisopropylamine. (Figures in bold face show reduction in MIC)

Table 3a MIC of Rifampicin alone and in combination with compound of formula Ia where R=CI and R ₅ +R<;=N,N-diisopropylamine. (Figures in bold face show reduction in MIC)

[0

Table 3b MIC of Rifampicin alone and in combination with compound of formula Ia where Ri=R ₂ =R ₃ =R ₄ =H, R=Cl and R ₅ +R ₆ =N,N-diethyIamine. (Figures in bold face show reduction in MIC)

Table 3c MIC of Rifampicin alone and in combination with compound of formula Ia where R=Br and R ₃ +R ₆ =isobutylamine. (Figures in bold face show reduction in MIC)

Table 3d MIC of Rifampicin alone and in combination with compound of formula Ia where R=H and R ₅ +R ₆ =N,N-diisopropylamine. (Figures in bold face show reduction in MIC)

Table 4a. MICs of Mupirocin alone and in combination With compound of formula Ia where (Figures in bold face show reduction in MIC)

Table 4b. MICs of Mupirocin alone and in combination with compound of formula Ia where Ri=R ₂ =R ₃ =RpH, R=CI and R ₅ +R ₆ =N,N-diethyIamine. (Figures in bold face show reduction in MIC)

Table 4c. MICs of Mupirocin alone and in combination with compound of formula Ia where R _t =R ₂ =Ra=^=H, R=Cl and Rs+R ₆ =3,4-methyIenedioxyaniline _i (Figures in bold face show reduction in MIC)

10

Table 4d. MICs of Mupirocin alone and in combination with compound of formula Ib where and R ₇ =methyl. (Figures in bold face show reduction in MIC)

15

>0

Table 4e. MICs of Mupirocin alone and in combination with compound of formula Ia where Ri=R ₂ =Ra=Ri=H, R=Br and R ₅ +R6=isobutylamine. (Figures in bold face show reduction in MIC)

Table- 4f. JMICs of Mupirocin alone and in combination with compound of formula Ia where (Figures in bold face show reduction in MIC)

10

[5

Advantages of the invention

The present invention discloses the preparation of a novel class of compounds Le 3-( unsubstitύted-or-substituted-3,4-dihydronaph-2yl-)-acrylic acid amides,5— (unsubstituted-or

substituted-3,4-dihydronaph-2yl-)4-substitued-2E,4E-penta dionic acid amides and the saturated derivatives of these compounds ,the whole class of compounds not reported hitherto in the literature and their use as potentiators of antibiotics (i.e as efflux pump inhibitors of bacteria) when used in combination with antibiotic and tested against bacteria. The synthesised molecules have shown high potency in terms of lowering of MIC of the drug ciprofloxacin (thirtytwo fold) compared to the MIC levels of drug when used alone. These classes of compounds have shown potentiation of the in-vivo efficacy of the drugs when tested in in-vivo animal experimental models.

This is exemplified by a typical topical formulation of mupirocin in combination with the compound of formula 1 (where R ₁ =R ₂ =R ₃ =R ₄ =H, R=Cl and R ₅ +R ₆ =N,N-diisopropylamine) when used in defined ratio showed better efficacy than the original mupirocin in the mice dermal infection model (Table 5)