The invention relates to novel N-hydroxyalkyl substi tuted 1,2,3,6-tetrahydropyridine and piperidine deriva¬ tives, to processes and intermediates for their prepara¬ tion, to pharmaceutical compostions containing them and to their medical use.

International Patent Application PCT/HU90/00076 describes tetrahydropyridine derivatives structurally related to the compounds of the invention which are said to have antiamnesic activity. In contrast to the present compounds, however, said compounds can be considered as β- or τ-amino ketone compounds the nitrogen atom of whic is closed as a ring member into said substituted tetra¬ hydropyridine ring.

The invention relates to novel, therapeutically acti N-hydroxyalkyl-substituted 1,2, 3, 6-tetrahydropyridine an piperidine derivatives of the formula

wherein

A stands for hydrogen or halogen; alkoxy; cyano; phenyl; phenyl monosubstituted by halogen; benzyl; benzyl monosubstituted by halogen; 2-phenylethyl monosubstituted by halogen on the phenyl moiety; or 2-picolyl group;

76080-67 SI

B represents hydrogen; alkoxy or nitro group; D represents hydrogen or halogen; or alkoxy grou or B and D together stand for a -CH=CH-CH=CH- group; R represents hydrogen; alkyl or phenyl group; G is hydrogen;

I stands for hydrogen or hydroxy group; or G and I together represent a single chemical bond; E stands for hydrogen or halogen; alkoxy or tri- fluoro ethyl group; and m is 0, 1 or 2, with the proviso that: is 0 or 2, or both G and I mean hydrogen, when stands for benzyl or halogen-monosubstituted benzyl group; and m is 1, when A stands for 2-picolyl group, as well as their acid addition salts.

Alkyl group as used herein either in itself or as a moiety of an other group, represents a straight or branched chain saturated hydrocarbon group containing 1-1 carbon atoms such as methyl, ethyl, n- and isopropyl, n-, o- _r sec- and tert-butyl groups as well as the various pentyl, hexyl, heptyl, octyl, nonyl and decyl groups. C^_galkyl groups are preferred, C^_ lk l groups are more preferable and methyl group is particularly favour¬ able.

Halogen may mean fluorine, chlorine, bromine or iodine. The following compounds are particularly preferred: l-[4-(4-chlorobenzyl)phenyl]-2-(4-phenyl-l,2,3,6-tetra- hydro-1-pyridyl)ethanol,

1-[4-(4-chlorobenzyl)phenyl]-3-(4-phenyl-l-piperidyl)- propanol, l-[4-(4-chlorobenzyl)phenyl]-4-(4-phenyl-l,2,3,6-tetra-

hydro-1-pyridyl)butanol,

3-[4-(4-fluorophenyl)-l-piperidyl]-l-(l,1'-biphenyl-4-yl propanol,

3-[4-(4-chlorophenyl)-1,2,3,6-tetrahydro-l-pyridyl]-1- (2,4-dichlorophenyl) ropanol.

The present invention also relates to a pharma¬ ceutical composition for treating conditions selected from hypoxia and ischaemia comprising an amount of a com pound of formula (I) or a pharmaceutically acceptable ac addition salt thereof effective in treating such condi¬ tions and a pharmaceutically acceptable carrier.

Furthermore, the present invention also relates to a process and intermediates for the preparation of the com pounds of formula (I) , as well as acid addition salt thereof.

Additionally, the present invention relates to a process for the preparation of pharmaceutical compositio comprising a compound of formula (I) or a pharmaceutical acceptable acid addition salt thereof. The present invention also relates to a method of treatment, which comprises administering a therapeuticall effective amount of a compound of formula (I) or a pharma ceutically accaptable acid addition salt thereof to a mammal (including man) for strengthening its tolerance against hypoxic and/or ischaemic conditions as well as for treating degenerative and functional disturbances arising from hypoxic and/or ischaemic insults.

Surprisingly, it has been found that the compounds of formula (I) are capable to protect the brain from the cognitive function-injuring effect of various harmful conditions, e.g. hypoxia and/or ischaemia; or they are useful to enhance the tolerance against hypoxic and/or ischaemic conditions, respectively as well as to treat degenerative and functional disturbances arising from hypoxic and ischaemic insults.

The biological effects of compounds according to the invention are hereinafter illustrated by using the follow ing test methods.

Male CFLP mice (from the Hungarian stock LATI) weighing 24-26 g each and spontaneously hypertensive (SH) male rats weighing 160-180 g each, respectively were used in these investigations. The compounds to be tested were orally administered in a volume of 10 ml/kg one hour prior to start the experiment. Antihypoxic effect in mice

1. The cytotoxic hypoxia test

After a 1-hour pretreatment, the animals were intra¬ venously injected with 5 mg/kg of potassium cyanide. Sur¬ vival time was measured as an interval lasting from the administrating of potassium cyanide to the last respira¬ tory movement. In the groups consisting of 10 animals each treated with the compounds, the animals having a survival time longer by 30% than the average survival time of the placebo-treated group were considered to be protected. The ED5 ₀ values (i.e. the doses being effective in 50% of the animals) were calculated from the percentage of the surviving animals by using probit analysis. 2. The hypobaric hypoxia test

After a 16-hour starving and 1-hour pretreatment period, the animals were placed in a desiccator of 6 lit¬ res volume, where the pressure was decreased to 170 -mmHg within 20 seconds. The survival time was registered from this time point up to the last respiratory movement of the animals. Animals having a survival time longer by 30% than the average survival time of the control group were con¬ sidered to be protected. The ED5 ₀ values were calculated from the percentage of the animals protected by using probit analysis.

The results obtained are summarized in Table 1.

Table 1

Compound Oral ED ₅₀ (mg/kg) (Sign)

Cytotoxic hypoxia Hypobaric hypoxi in mice in SH rats

A 11.9 18.5

B 19.8 11.5

C 18.8 7.3

D 50.0 3.7

E >50.0 8.3 Vincamine 27.0 27.9 Piracetam 131.5 293.0

The chemical names of compounds listed in Table 1 are as follows.

"A": 1-[4-(4-chlorobenzyl)phenyl]-2-(4-phenyl-l, 2,3,6- tetrahydro-1-pyridyl)ethanol;

^■ B' 1-[4-(4-chlorobenzyl)phenyl]-3-(4-pheny1-1- piperidy1)propanol; li II l-[4-(4-chlorobenzyl)phenyl]-4-(4-phenyl-l, 2,3,6- tetrahydro-1-pyridyl)butanol;

^• D' 3-[4-(4-fluorophenyl) -l-piperidyl]-l-(1,1 '-bi- phenyl-4-yl)propanol; and

IITΓII 3-[4-(4-chlorophenyl) -1,2,3, 6-tetrahydro-l-pyridyl] l-(2 ,4-dichlorophenyl)propanol. Various forms of hypoxia were used for investigating the compounds. The functional dysorganization and destruc tion of cells and death, respectively in otherwise healthy mice are caused by a decrease in the oxygen-satu¬ ration of haemoglobin in the hypobaric hypoxia and the inhibition of the mitochondrial respiratory enzyme in the

cytotoxic hypoxia. Spontaneously hypertensive (SH) rats are more sensitive against hypoxic conditions than normo tensive animals; similarly, patients suffering from hype tension have a less chance of survival after hypoxic injuries.

Vincamine [chemically (+)-14β-hydroxy-14α-methoxy- carbonyl-14,15-dihydroeburnamenine] and piracetam (chemically 2-oxo-l-pyrrolidinylacetic acid amide) were used as reference drugs. Vincamine increases the oxygen supply (vasodilatory effect) and modulates the metabolic processes of brain (cerebroprotective effect) whereas piracetam improves mainly the adaptation ability of brain in pathologic states.

The antihypoxic effect of vincamine is most pronounce in cytotoxic hypoxia and in addition, it has a prominent tolerance-enhancing action in the hypobaric hypoxia. Essentially, piracetam exerts its effect in the same two tests.

The compounds according to the invention are more active in both tests in comparison to the reference drugs. It is particularly favourable that the antihypoxic effect is strongest -in spontaneously hypertensive animals, which is a substantial therapeutical advantage under pathologic conditions. The antihypoxic effect of compound "A" is the most favourable, since its effects are the same in the various tests of hypoxia and it is 2- or 3-times as effective as vincamine.

Acute toxicity study in mice OF-1 mice of either sex weighing 19-21 g were used. The test compound was administered through a catheter inserted into the stomach. A series of solutions was prepared, the concentrations were chosen to give a constan dosage volume of 0.1 ml/10 g. The observation time after the treatment was 72 hours. The LD5 ₀ value was calculated

according to Litchfield and Wilcoxon from six dose res¬ ponses (maximal dose 1000 mg/kg p.o., n = 10).

Compound LD ₅₀ (mg/kg p.o.)

A > 1000

E > 1000

B 697

The active agents of formula (I) can be formulated in pharmaceutical compositions by mixing them with non-toxic, inert, solid or liquid carriers and/or auxiliaries common¬ ly used in the therapy for parenteral or enteral admi- nistration. Useful carriers are e.g. water, gelatine, lactose, starch, pectin, magnesium stearate, talc, vege¬ table oils such as peanut oil, olive oil and the like. The active agent can be formulated in any usual pharma¬ ceutical composition, particularly solid composition, e.g. rounded or edged tablet, dragee or capsule such as gela¬ tine capsule, pill, suppository and the like. The amount of the solid active ingredient may be varied within a broad range in a dosage unit of the composition (tablet, ' capsule, one unit of the formulated solution and the like) preferably it is between about 25 mg and 1 g. Optionally, these compositions may also contain other commonly used pharmaceutical auxiliaries, e.g. stabilizers, preserva¬ tives, wetting agents, emulsifying agents and the like. The compositions can be prepared in a known manner, e.g. by sieving, mixing, granulating and compressing the com¬ ponents in the case of solid compositions. The composi¬ tions may be subjected to other usual operations of the pharmaceutical technology, e.g. sterilization.

The dose to be used may be varied between wide limits 5 depending on the body-weight and responsiveness of the

person or animal to be treated, as well as on the severit of the state to be influenced, frequency and route of administration; however, the suitable dose can easily be determined by a physician skilled in the art. The proposed daily doses of the active compounds of the invention for oral or enteral administration to the subject for the treatment of the conditions referred to above are between 0.1 to 50 mg of the active ingredient per kg body weight; however, this limit may be exceeded depending on the severity of the pathological state to be treated since the toxicity of the compounds of the invention is low. The daily dose of the active compound may be administered once or in subdoses to the patient to be treated. According to an other aspect of the invention, there is provided a process for the preparation of compounds of the formula (I) , which comprises treating an oxo deriva¬ tive of the formula

B D

wherein A, B, D, R, G, I, E and m are as defined above, o an acid addition salt thereof with a reducing agent in an organic solvent and then, if desired, converting the obtained N-hydroxyalkyl-substituted 1,2,3,6-tetra- hydropyridine or piperidine derivative of formula (I) , wherein A, B, D, R, G, I, E and m are as defined above, t an acid addition salt thereof by reacting it with a mineral or organic acid.

Useful reducing agents for this purpose are complex metal hydrides, preferably sodium borohydride, though thi reduction can also be accomplished e.g. by means of the Meerwein-Ponndorf-Verley reduction [Ann. Chem. 444, 221 (1926); Angew. Chem. 3_9 138 (1926)], e.g. by using an aluminium alkoxide in isopropanol medium. The reduction of the oxo derivatives of formula (II) by sodium borohydride is preferably carried out in such a way that an acid addition salt of a compound of formula (II) is used as starting substance and the base is li¬ berated in situ in the reaction medium. The reduction is accomplished in a lower alcohol or in the mixture of such an alcohol and water. In order to make the reac¬ tion complete, the reducing agent is employed in an excess or the temperature of the reaction is elevated to the boiling point in the final period. The product obtained is isolated by filtration or ex¬ traction. It is suitable to dilute the reaction medium with water for completing the precipitation of the product. When extraction is used, a part of alcohol is evaporated, then the reaction mixture is diluted with water and the product is extracted into a water-immiscibl hydrocarbon, chlorinated hydrocarbon, ethyl acetate or ether. The final product may be purified by recrystalli- zation. If desired, the compounds of formula (I) obtained in the base form can be converted to their acid addition salts by reacting them with an organic or inorganic acid

for the salt formation in a known way. Hydrochloride salt are preferred.

The oxo compounds of formula (II) and their addition salts are also novel. These compounds can advantageously be prepared from hydrogenated pyridine derivatives of the formula

wherein G, I and E are as defined above as starting material by either of two methods, which comprises a) alkylating a compound of formula (III) with a halo- genated ketone of formula

(IV)

wherein A, B, D and R are as defined above and X stand for halogen, preferably chlorine or bromine, to obtain compounds of formula (II) , wherein m is 0 or 2; or b) reacting a compound of formula (III) with an acetophe- none or propiophenone of formula

wherein A, B, D and R are as defined above and R ¹ mean hydrogen or methyl group, in the presence of formal¬ dehyde under conditions of the Mannich's reaction [Arch. Pharm. 250, 647 (1912)] to obtain compounds of formula (II), wherein is 1. A number of substances of formula (IV) , e.g. phenacyl halides, α-bromόpropiophenone [J. Chem. Soc. 125 2343 (1924)], desyl bromide or 2-bromoacetophenone [Ann. 155, 68 (1870)] are known from the literature. Both latter com pounds can be prepared by brominating the appropriate ketone; whereas the compounds of formula (IV) , wherein m is 2 are mainly prepared by reacting an aromatic compound of formula

wherein A is as defined above and B as well as D prefer ably stand for hydrogen, with 4-chlorobutyryl chloride under Friedel-Crafts condition.

Starting compounds of formula (V) are commercially available products.

Compounds of formula (VI) can be produced by reactin a compound of formula (V) with an appropiate acid chlori under Friedel-Crafts condition. The ketone synthesis is not necessarily the final step of preparing the compound of formula (VI) ; the formation of a substituent on the aromatic ring may also be the last step.

The invention is illustrated in detail by the follow ing non-limiting Examples. Example 1 Preparation of l-(4-chlorophenyl)-3-[4-hydroxγ-(4- c lorophenyl)-l-piperidyl] ropanol

To a solution containing 1.2 g (0.03 ol) of sodium hydroxide in 50 ml of an 50% by volume ethanol/water mixture, 12.41 g (0.03 mol) of l-(4-chlorophenyl)-3-[4- hydroxy-(4-chlorophenyl)-l-piperidyl]propanone hydro¬ chloride and then, during 1 hour 1.17 g of sodium boro¬ hydride are added. The suspension is heated at a tempe¬ rature of 50 °C for 2 hours. After cooling down, the reaction mixture is filtered and washed with water to giv 11.45 g of product, m.p.: 129-132 °C. After recrystalliza tion of the latter product from 215 ml of acetonitrile, 9.1 g of title compound are obtained. Analysis for C ₂ o ^H ₂₃ ^c l2 ^N0 2 (molecular weight 380.30) calculated: C 63.16; H 6.10; Cl 18,65; N 3.68%; found: C 62.94; H 6.17; Cl 18.41; N 3.48%. Example 2

Preparation of 3-[4-(4-chlorophenγl)-1,2,3,6-tetra- hydro-1-pyridyl]-1-(2,4-dichlorophenyl)propanol After adding 12.93 g (0.03 mol) of 3-[4-(4-chloro- phenyl)-1,2,3,6-tetrahydro-l-pyridyl]-1-(2,4-dichloro-

phenyl)propanone hydrochloride to a solution of 1.2 g (0.03 mol) of sodium hydroxide in 50 ml of methanol, 1.17 g of sodium borohydride are portionwise added to the above mixture during 1 hour. After terminating the addi- tion, the reaction mixture is boiled under reflux for 3 hours, then the reaction mixture is poured into 150 ml of water. The major part of methanol is distilled off from the so-obtained oily precipitate, which is then twice extracted with 50 ml of ethyl acetate each. After eva- porating the solvent, 12.3 g of evaporation residue are obtained to give a crystalline product on addition of 50 ml of diisopropyl ether. In this way 8.32 g of title product are obtained, which is recrystallized from 28 ml of isopropanol to obtain 6.3 g of title compound, m.p. : 96-98 ^C C.

Analysis for C2o ^H 20 ^cl 3 ^NO (molecular weight 396.74) calculated: C 60.54; H 5.08; Cl 26.81 N 3.53%; found: C 60.80; H 5.03; Cl 26.62; N 3.60%. The compounds listed hereinafter are prepared as described above by using the appropriate propanone derivatives of formula (II) as starting materials. The hydrochloride salts are obtained by adding ethanolic hydrogen chloride solution to the corresponding base.

1) l-[4-(4-Chlorobenzyl)phenyl]-2-(4-phenyl-l,2,3,6- tetrahydro-l-pyridyl)ethanol, yield 93.2%, m.p.: 135-137 °C;

2) l-[4-(4-chlorobenzyl)phenyl]-3-(4-phenyl-l-piperidyl) - propanol, yield 93.8%, m.p.: 98-101 °C; 3) 1-[4-(4-chlorobenzyl)phenyl]-4- (4-phenyl-l, 2, 3, 6- tetrahydro-1-pyridyl) butanol, yield 78.5%, m.p.: 108-111 °C; 4) 3-[4-(4-fluorophenyl) -l-piperidyl]-l-(l, 1 '-bi- phenyl-4-yl)propanol, yield 90.7%, m.p.: 129-132 °C;

5) l-phenyl-2-[4-(3-trifluoromethylphenyl)-1,2,3,6- tetrahydro-1-pyridyl]ethanol, yield 80.5%, m.p.: 188-190 °C;

6) 3-[4-(4-chlorophenyl)-1,2,3, 6-tetrahydro-l-pyridyl]- 2-methyl-l-phenyl-propanol, yield 80.9%, m.p.: 103-105 °C;

7) l-(4-chlorophenyl)-3-[4-(4-chlorophenyl) -1,2,3,6- tetrahydro-1-pyridyl]propanol, yield 82.8%, m.p.: 154-155 °C; 8) l-(4-chlorophenyl)-3-[4-(4-chlorophenyl)-1,2,3,6- tetrahydro-1-pyridyl]-2-methylpropanol, yield 84.0%, m.p.: 110-112 °C; 9) 1-(4-chlorophenyl)-2-[4-(4-chlorophenyl) -1,2,3,6- tetrahydro-1-pyridyl]ethanol , yield 60.4%, m.p.: 152-153 °C;

10) 3-[4-(4-chlorophenyl)-1,2,3,6-tetrahydro-l-pyridyl]- 1-(3-methoxypheny1)propanol, yield 87.4%, m.p.: 100-102 °C;

11) l-(4-chlorophenyl)-3-[4-(4-chlorophenyl)-l-piperidyl] propanol, yield 84.7%, m.p.: 152-154 °C;

12) 1-(4-chlorophenyl)-3-[4-(4-fluorophenyl)-l-piperidyl] propanol, yield 70.5%, m.p.: 108-110 °C; 13) l-(4-chlorophenyl)-3-(4-phenyl-l,2,3,6-tetrahydro-l- piridyl)propanol , yield 74.1%, m.p.: 141 °C;

14) 1-(4-fluorophenyl)-3-[4-hydroxy-(4-chlorophenyl)-1- piperidy1]propanol, yield 93.4%, m.p.: 116-118 °C;

15) l-(2,4-dichlorophenyl)-3-[4-hydroxy-(4-chlorophenyl)- l-piperidyl]propanol, yield 78.8%, m.p.: 146-148 °C;

16) l-(2,4-dimethoxyphenyl)-3-[4-hydroxy-(4-chlorophenyl) - l-piperidyl]propanol ,

yield 69.2%, m.p.: 129-130 °C; 17) 4-[4-(4-chlorophenyl) -1,2,3, 6-tetrahydro-l-pyridyl]-1- (4-fluorophenyl)butanol, yield 90.1%, m.p.: 103-105 °C; 18) l-[4-(4-chlorobenzyl)phenyl]-4-[4-(4-chlorophenyl) - 1,2,3, 6-tetrahydro-l-pyridyl]butanol, yield 90.7%, m.p.: 104-105 °C;

19) l-(4-cyanophenyl) -3-[4-(4-chlorophenyl) -1,2,3, 6-tetra¬ hydro-l-pyridyl]propanol, yield 76.5%, m.p.: 117-118 °C;

20) l-{4-[2-(4-chloropheny1)ethyl]phenyl}-3-(4-pheny1- 1,2,3, 6-tetrahydro-l-pyridyl)propanol, yield 83.1%, m.p.: 158-160 °C;

21) l-(4-cyanophenyl) -3-[4-(4-methoxyphenyl) -1,2, 3 , 6- tetrahydro-1-pyridyl]propanol, yield 74.7%, m.p.: 144-145 °C;

22) l,2-diphenyl-3-[4-hydroxy-(4-chlorophenyl) -l-pi¬ peridyl]propanol, yield 68.7%, m.p.: 150-151 °C; 23) 3-[4-(4-chlorophenyl) -1,2, 3, 6-tetrahydro-l-pyridyl]- l-[4-(2-picolyl)phenyl]propanol, yield 40.0%, m.p.: 129-131 °C;

24) 3-[4-(4-chlorophenyl) -1,2,3, 6-tetrahydro-l-pyridyl]- 1 ,2-diphenylpropanol, yield 82.7%, m.p.: 135-137 °C;

25) 3-[4-(4-chlorophenyl) -1,2,3, 6-tetrahydro-l-pyridyl]- 1-(4-methoxypheny1)propanol, yield 82.9%, m.p.: 116-118 °C;

26) 1-(1-naphthyl) -3-(4-phenyl-l,2,3, 6-tetrahydro-l- pyridyl)propanol, yield 88.8%, m.p.: 93-94 °C;

27) 3-[4-(4-chloropheny1) -1,2, 3, 6-tetrahydro-l-pyridyl]- 1-(1-naphthyl)propanol, yield 75.4%, m.p.: 122-123 °C; 28) 3-[4-(4-chlorophenyl) -1,2,3, 6-tetrahydro-l-pyridyl]-

1-(2,4-dimethoxyphenyl)propanol, yield 54.7%, m.p.: 112-114 °C;

29) 3-[4-(4-chlorophenyl)-1,2,3,6-tetrahydro-l-pyridyl]- l-(4-fluoro-3-nitrophenyl)propanol, yield 30.0%, m.p.: 154-156 °C;

30) l-[4-(4-chlorobenzyl)phenyl]-3-[4-(4-fluorophenyl)-1- piperidyl]propanol, yield 83.4%, m.p.: 94-95 °C;

31) 1-(1,1•-biphenyl-4-yl) -3-(4-phenyl-l-piperidyl)pro- panol, yield 87.7%, m.p.: 99-101 °C;

32) 3-[4-(4-chlorophenyl)-1,2,3, 6-tetrahydro-l-pyridyl]- 1-(4-fluorophenyl)propanol, yield 90.5%, m.p.: 130-132 °C; 33)- 1-[4-(4-chlorobenzyl)phenyl]-2-[4-(4-chlorophenyl)- 1,2,3, 6-tetrahydro-l-pyridyl]ethanol, yield 87.3%, m.p.: 149-152 °C; 34) 1-(2,4-dichlorophenyl)-3-(4-phenyl-l,2,3,6-tetrahydro l-pyridyl)propanol, yield 57.3%, m.p.: 103-104 °C; 35) l-(l,l ^« -biphenyl-4-yl)-2-(4-phenyl-l,2,3,6-tetra¬ hydro-l-pyridyl)ethanol, yield: '68.8 %, m.p.: 190-197 °C;

36) 1-(1,1 ^« -biphenyl-4-yl)-2-[4-(4-fluorophenyl) -1,2,3,6- tetrahydro-1-pyridyl) thanol, yield: 76.9 %, m.p.: 202-207 °C;

37) 2-(4-phenyl-l,2 ,3,6-tetrahydro-l-pyridyl)-1-(4 ^» - fluoro-1,1'-biphenyl-4-yl)ethanol, yield: 96.6 %, m.p.: 207-210 °C; and

38) 2-(4-phenyl-l,2,3,6-tetrahydro-l-pyridyl) -l-[4-(4- fluoro-benzyl)phenyl]butanol, yield: 76.2 %, m.p.: 164-167 °C. Example 3

Preparation of tablets a) Tablets weighing 150 mg, containing 5 mg of active ingredient each

g

Active ingredient 5

Gelatine 3

Magnesium stearate 2 Talc 5

Potato starch 40

Lactose 95 b) Tablets weighing 300 mg, containing 50 mg of active ingredient each

g

Active ingredient 50

Polyvidone 6

Magnesium stearate 3 Talc 9

Potato starch 84

Lactose 148

After wet granulation, the powder mixture containing the ingredients given above under a) or b) , respectively is compressed to tablets. Each tablet weighs 150 mg or 300 mg, respectively and contains 5 or 50 mg, respectivel of active ingredient.