The present invention refers to (5-amino-2-hydro- xy)benzoic acid derivatives having formula I

wherein: B^ is the. imidazolium or C- or N-substituted imidazolium cation, lysine or similar basic aminoacids or methyl- glucamine; R represents:

- hydrogen or a linear C -C alkyl chain, optionally substituted by one or more chlorine or fluorine atoms, free, etherified or esterified hydroxy groups, carboxy, carboxyalkyl, aminocarbonyl or N-substituted aminocarbo- nyl groups, one or more of the -CH - groups being optio¬ nally substituted by keto groups; - a chain of formula:

wherein n is an integer from 1 to 10 and R and R , which may be the same or different, are H, halogens, is hydrogen or C -C lower alkyl; - a chain of formula:

-(CH_) -Het 2 m wherein m is an integer from 0 to 20 and Het is an op¬ tionally substituted 5- or 6-membered heterocyclic group containing one or more N, 0 or S atoms such as pyrrole, pyridine, furan, pyran, thiophene, oxazole, isoxazole, imidazole, pyrazole, thiazole groups^ - a chain of formula:

wherein p is an integer from 0 to 16;

- a chain of-formula:

wherein q is an integer from 1 to 16;

- an ary ^' l or aralkyl residue such as phenyl; phenyl sub¬ stituted by one or more fluorine or chlorine atoms, fluoroalkyl, alkoxy, alkoxycarbonyl, C -C lower alkyl, amino, dialkylamino, hydroxy, cyano groups or by groups of formula NHCOR wherein R has the above defined mean¬ ings; diphenyl; naphtyl groups;

- a chain of formula:

wherein m has the above defined meanings and R is hy¬ drogen or a linear or branched, saturated or unsaturat- ed, C -C alkyl group; - a chain of the formula:

wherein R_, R_ and R , which may be the same or diffe- 5 6 7 rent, are H, OR (R having the above defined meanings), NH , NHCOR , chlorine or fluorine atoms, fluoroalkyl groups;

- a chain of formula:

wherein R is hydrogen, lower alkyl, fluorine or fluoro- 8 alkyl;

- a linear or branched chain of the formula:

-(CH2_)n-X-CrH-(CH2_)n, ¹ -Y-

^R 3 wherein R and n have the above defined meanings, n" is an integer from 1 to 10 and X and Y are an oxygen, ni¬ trogen, sulphur atom or a CH group;

- a chain of formula:

-(CH ) -S-R. 2 r 3 wherein r is an integer from 1 to 3 and R has the above

defined meanings;

- an aminoacid residue, namely L-leucyl, of or ^" -L-glu- tamyl- in a free form or protected with the conventional amine protecting group, such as BOC; - an Arg-Pro-D(Phe) chain or the like;

- an uronic residues of formula:

Another object of the invention is provided by a process for the preparation of the compounds I as well as by pharmaceutical compositions containing them as the active principle. The acids 5-(2,4-dichlorobenzoylamino)-2-hydroxy benzoic, 5-(cyclohexylmethylamino)-2-hydroxy benzoic, 5-(linoleylamin ^' o)-2-hydroxy benzoic, 5-(arachidylami.no)- 2-hydroxy benzoic, 5-(arachidonylamino)-2-hydroxy benzoic, 5-(2,6 or 3,5-difluoro-phenyl)-2-hydroxy benzoic, 5-(4-cy- clohexyl-butanoylamino)-2-hydroxy benzoic, 5-/2-(3-pyri- dyl)acetylamino7-2-hydroxy benzoic, 5- 4-(phenyl)benzoyl- aminq/-2-hydroxy benzoic, 5-(m-trifluoromethyl-cinnamo- yl)-amino-2-hydroxy benzoic, 5- 8-(1-imidazolyl)-octano- yl7amino-2-hydroxy benzoic are per se new and are therefo- re comprised within the scope of the present invention, as well as the salts thereof with pharmacologically accepta¬ ble organic or inorganic bases and the pharmaceutical compositions containing them.

On the other hand, while the imidazole salts I are of course new, some of the corresponding acids (the anio-

nic component) are known, for instance from EP-A-45955, Ger. Offen. No. 2,031,227, 2,919,545, 2,920,292, Japan Kokai No. 78-9651, Biochem. Biophys. Res. Commun. V. 101, 258, 1981 and Bio ed. Mass Spectrom. 11, 539, 1984: no pharmacological activity thereof has been however describ¬ ed.

It has now been found that also these known compo¬ unds are endowed with surprising and advantageous pharma¬ cological properties. A further object of the invention is therefore provided by pharmaceutical compositions containing as the active principle said known acids, which will be herein¬ after specifically defined.

The preparation of the compounds of the invention is carried out starting from 5-amino-salicylic acid, whi- ch, in the presence of a suitable base (pyridine, triethy- la ine etc.), optionally diluted in a suitable solvent, is treated with equimolar amounts of an activate derivative, such as the acyl chloride or anhydride, of an acid of formula RCOOH wherein R has the above defined meanings. After stirring at the room temperature or under heating, a mixture of N,0-diacyl and of N-acyl product is usually obtained w ^' - ich is subjected to selective hydrolysis of the 0-acyl group in extremely mild conditions so as to respect both the N-acyl group and the nature of the acyl group itself. Said method is characterized by treating the acyl derivatives mixture, recovered from the reaction medium and dissolved in suitable solvent, with catalytic amounts of imidazole base in the presence of minor amounts of water. After stirring at room temperature, for different

times according to the considered acyl group, the recovery of the N-acyl derivative is carried out by solvent evapo¬ ration and subsequent recrystallization from a suitable solvent. The imidazole or substituted imidazole salts, as well as the pharmacologically acceptable metals or other organic bases salts, are prepared by mixing in a suitable solvent equimolar amounts of the corresponding acid and base. The recovery of the salt is carried out either by spontaneous precipitation from the reaction medium or by solvent evaporation under vacuum or by addition to the medium itself of a miscible precipitating solvent.

The following examples further illustrate the in¬ vention, without limiting the scope thereof. ^* EXAMPLE 1

1) 5-(2,4-Dichlorobenzoylaιτιino)-2-hydroxy-benzoic acid

20.95 Grams (0.1 mole) of 2,4-dichlorobenzoyl-chlo- ride are slowly added to a solution of 15.31 g (0.1 mole) of 5-amino-salicylic acid in 150 ml of anhydrous pyridine under stirring, in the dark and in nitrogen atmosphere. The solution is then poured in water-ice, filtered under reduce pressure and the obtained precipitate is washed with water to neutrality and dissolved in humid methanol.0.5 Grams of imidazole base are then added, and the mixture is stirred at the room temperature for 3 hours. The solvent is distilled off under vacuum and the residue is taken up with ethyl acetate,- washed with acidic H O (HCl) then with water to neutrality and dried on sodium sulphate. After solvent's evaporation, the residue is crystallized from methanol, yielding 17.49 g (53,63%), m.p. 233-235°C; I.R.:

elemental analysis, found (calc): C = 51.74 (51.55); H = 2.85 (2.78) ; N = 4.21 (4.29) . la) Imidazole salt

10 Grams (30.66 m oles) of the product 1 are dis- solved in 100 ml of methanol and added with 2.09 g (30.66 mmoles) of imidazole. The mixture is stirred for 3 hours and the solvent is then removed under reduced pressure. The residue is crystallized from methanol-water. 10.65 Grams of la are obtained (88.11%) having a melting point of 87-89°C; I.R. : 3140, 1650, 1585, 1320 cm ^"1 ; U.V. : 233, 253, 325 nm; elemental analysis, found (calc): C = 50.83 (51.80); H = 3.47 (3.23); N = 10.72 (10.66).

EXAMPLE 2 _• 2) 5-Hexadecanoylamino-2-hydroxy benzoic acid 15.31 Grams (0.1 mole) of 5-amino-salicylic acid are dissolved in 300 ml of anhydrous py idine. After cool¬ ing to 0°C, under nitrogen and in the dark, 41.23 g (0.15 moles) of hexadecanoyl chloride are slowly added under stirring. When the addition is over, stirring is continued for 3 hours, - the mixture is poured in 100 ml of water-ice and then extracted with ethyl acetate. The organic phase is washed with diluted hydrochloric acid, water and the solvent is evaporated under reduced pressure. The residue is taken up with 100 ml of acetone and 10 ml of water, 0.68 g of imidazole base are added and the mixture is stirred overnight. After solvent evaporation under reduced pressure, the residue is treated with ethyl acetate. The organic phase is washed with water, diluted hydrochloric acid- and water to neutrality. After drying on sodium sul- phate and filtration, the solvent is evaporated under

vacuum. The residue is crystallized from ethanol/water. Yield: 28 g (72%) .

The product melts at 185-187°C; I.R. : 3500, 3290, 1680, 1650, 1540, 1310 cm ^" ; U.V.: 223, 250, 325 nm; ele- mental analysis, found (calc): C = 70.13 (70.55); H = 9.41 (9.52) ; N = 3.42 (3.58) . 2a) Imidazole salt

11.74 Grams (30 mmoles) of the compound obtained in 2 are dissolved in 100 ml of acetone and added with 2.04 g (30 mmoles) of imidazole base. After stirring at room temperature for 5 hours, the solvent is evaporated under reduced pressure and the residue is crystallized from methanol-water.

11.35 Grams (82.34%) are obtained. M.p. 132-134°C; I.-R.: 3310, 1650, 1525, 1300 cm ^" ; U.V. : 233, 253, 325 nm; elemental analysis, found (calc): C = 67.58 (67.95); H = 8.78 (8.99) ; N = 8.82 (9.14) .

EXAMPLES 3-23 Using the same methods above described, starting from the suitable acyl derivatives, the compounds reported in the following table were prepared.

The integers followed by an a) designate the imida¬ zole salts while the free acids are designated by progres¬ sive integers. The melting points are in °C and the I.R. values are in cm . All the compounds have elemental ana¬ lysis in agreement with the calculated values.

- continued -

TABLE 1 (follows)

(*) Known from E.P. 45,955; r * * \ " " Biochem. Biophys. Res. Commun.-v.101, 258, 1981;

Ger. Offen. 2-031-227; **** ^* * " Biomed. Mass Spectrom, v. 11, 539, 1984. EXAMPLES 24-28 According to the same methods of the previous cla¬ ims, the following 5-acyloyl-amino-salicylic acids were prepared (I.R. values in cm .and elemental analysis in agreement) :

24- 2-hydroxy-5-( 4-cyclohexyl-butanoyl)-amino benzoic acid; m.p. : 196-198°C; I.R.: 3500, 3250, 1680, 1650, 1540, 1310;

25- 2-hydroxy-5-(2-(3-pyridyl)-acetyl)-amino benzoic acid; m.p. : 221-223°C; I.R.: 3510, 3260, 1680, 1640, 1540, 1300;

26- 2-hydroxy-5-( 4-phenyl-benzoyl)-amino benzoic acid; m.p. : 178-180°C; I.R.: 3520, 3260, 1680, 1640, 1530, 1300;

27- 2-hydroxy-5-(m-trifluoromethyl-cinnamoyl) -amino benzoic acid; m.p. : 162-168°C; I.R.: 3500, 3250, 1660, 1635, 1500, 1300; 28- 2-hydroxy-5-( 8-( 1-imidazolyl)-octanoyl ) -amino ben-

zoic acid; m.p. : 183-186°C; I.R.: 3510, 3260, 1680, 1635, 1510, 1300. The corresponding imidazolium salts as well as other pharmaceutically acceptable salts of the above com- pounds are prepared according to the above described me¬ thods. BIOLOGICAL ACTIVITIES

The hereinabove mentioned compounds have been te¬ sted on in vitro and in vivo assays, with the aim of giv- ing evidence to their potential biological activities. Soy lipoxygenase inhibition activity

This assay allows to show the presence of an inhi¬ bitory activity on soy lipoxygenase considered as a model of the human enzyme. In mammals, this enzymatic system promotes the arachidonic acid transformatipn in leukotrie- nes A4 and B4. These compounds are indicated to be funda¬ mentally responsible for the flogosis. Namely, the leuko- trienes A4 and B4, show a relevant pro-inflammatory acti¬ vity in the bowel1 inflammatory disease and in the Crohn' disease.

The soy lipoxygenase (E.C. 1.13.11.12), has been tested according to the method of Axelrod et al. (Axelrod B. - Cheesbrough T.H., Laakso S. in Methods in Enzymology, vol. 71, pag. 441, 1981 - Academic Press N.Y.), in the presence and in-the-absence of the—products to be assayed, using nordihydroguaiaretic acid as test reference, at room temperature.

In Table 2, as not limiting example, the results obtained with the compounds 1, la to 18, 18a are shown. In this and in the following tables, as in Table 2,

the integers designate the free acids while the integers followed by the letter a relate to the corresponding imi¬ dazolium salts.

TABLE 2

- continued -

TABLE 2 ( follows )

Compound Inhibition (%) Concentration (Mxl0~ ⁶ )

13 14 150

13a 22 150

14 42 75

14a 78 75

15 24 150

15a 38 150

16 35 150

16a 51 150

17 26 150

17a - ⁴ 2 150

18 50 250

18a 82 250

Activity on platelet aggregation and thromboxane A2 pro¬ duction Measurements were carried out on in vitro tests with citrated platelet-rich plasma (P.R.P.), obtained from New-Zealand rabbits. Platelet aggregation was carried out according to the method of Born (Born G.V.R. - Nature, vol. 162, 67) using arachidonic acid 0.25 mM as aggrega- ting agent.

The inhibition activity was evaluated as ED50 (in mM) , i.e. the dose which antagonizes 50% of the aggregat¬ ing effect of arachidonic acid.

The thromboxane A2 production was measured by a bioassay test according to Moncada et al. (Moncada S.,

Ferreira S.H., Vane J.R. - Adv. Prost. & Thromboxanes Res. - Frolich J.C. Ed., Vol. 5, 211, 1978 - Raven Press). At scheduled times after the addition of arachidonic acid, 200 ul of P.R.P. was bioassayed for the TXA2 production and prostaglandin-like activity, on a tissue ^' sequence (cascade), composed of a spiral strip of rabbit aorta and a stomach fundus strip of rat.

The inhibition activity of the tested compounds on TXA2 production was evaluated as ED50 (in M) , i.e. the concentration able to decrease the contracturant effects of TXA2 on tissues.

The tested compounds were dissolved in Tween 80 and added to the P.R.P. at increasing concentrations, until the determination of the ED50 was achieved. In- Table 3, as not limiting example, the results obtained using some of the compounds of the invention are reported.

TABLE 3 Inhibition (ED50, in M) on arachidonic acid induced:

ANTIINFLAMMATORY ACTIVITY ON NON-IMMUNE AND IMMUNE INFLAM¬ MATION 1 - Carrageenin induced pleurisy in rats (non-immune in¬ flammation)

The test has been performed according to Di Rosa et al. (Di Rosa M. , Giround J.P., Willoughby D.A. - J. Path. Bact., vol. 104, 15, 1971). A 1% solution (0.15 ml) of carrageenin in 0.9% NaCl, was injected into the pleural cavity of Sprague-Dawley rats, weighing about 250 g. Six hours later, the animals were sacrificed, the pleural exudate volumes were measured and the leukocytes total number was counted by a micro- cell-counter, being the cavity rinsed by 0.5 ml of a sali-

ne medium.

The % inhibition of leukocytes total number was calcu¬ lated versus control animals. The assayed compounds were administered orally, 1 mM/kg, 30' before the carrageenin injection in the pleural cavity. In Table IV, as not limi¬ ting example, the results obtained with some of the compo¬ unds of the invention are reported.

TABLE 4 % Inhibition on:

- continued -

TABLE 4 (follows)

- continued -

TABLE 4 ( follows )

(*) L-Leucyl-5-amino-salicylic, described in Ger. Offen. ^' 2,919,545;

(**) T-L-Glutam"yl-5-amino-salicylic, described in Ger.

Offen. 2,920,292; (***) Aceto acetyl-5-amino-salicylic, described in Japan Kokai 78-9651.

2 - Reserve passive Arthus reaction in rat paws (Immune inflammation)

The assay has been performed according to Gemmel et al. (Gemmel D.K. Cottney J., Lewis A.J. - Agents Actions, vol. 9, 107, 1979). 1 Ml of a rabbit anti-bovine-albumin serum (freeze-dried antibodies, dissolved in 2 ml of 0.9% NaCl) was injected into the caudal vena of Sprague-Dawley male rats.

30' Later, 0.025 mg of bovine albumin (in 0.1 ml sali¬ ne) was injected in the subplantar paw. The volume of the paw was measured 5 hours later, by a mercury plethysmome- ter.

The tested compounds were orally administered 3 hours before the bovine albumin treatment. The % inhibition of the rat foot volume increase was calculated in confront to the increase of the foot volume of untreated animals. The results obtained with some of the compounds of the inven¬ tion are reported in Table 5.

TABLE 5

- continued -

TABLE 5 ( follows )

Na-5-ASA: 5-amino salicylic acid sodium salt

The numbers in parenthesis indicate the administered dose in mg/kg.

The orally administrations are equivalent to one mM/kg for each tested compound.

3 - Acetic acid bowel inflammation in rats (non immune bowel inflammation)

The assay has been performed according to Sharon (Sharon P., Stenson W.F. - Gastroenterology, vol. 88, 55, 1985) .

Considering the nature of the assay, the test was performed mainly on the compounds of ^* the invention not well absorbed, according to the results, obtained in the previous tests. ^* It should be noted, however, that all the claimed derivatives can be usefully applied in the therapy of the bowel inflammation and in the Crohn' disease.

The results are reported in the following Table 6.

The administered doses (via intra-bowel, during the bowel ligature and the local injection of the acetic acid) were 0.5 mM/kg, for all the tested compounds, dispersed" in carboxymethylcellulose. The % reduction of the ulceration index has been calculated versus untreated animals.

TABLE 6

Compounds % Reduction of the ulceration index

2 -36

2a -51

14 -38

14a -58

19 -42

19a -65

20 -42

20a • -65

Acute toxicity

The compounds of Table 1 have been subjected to the acute toxicity test in mice, by the oral route, in carbo¬ xymethylcellulose suspensions. All the LD proved to be higher than 1600 mg/kg.

The present invention refers also to all the indu¬ strial applicable aspects connected with the use of the compounds I and of the corresponding free acids as thera¬ peutic agents. An essential aspect, of the invention is therefore provided by pharmaceutical compositions contain¬ ing, as the active principle, predetermined and therapeu- tically effective amounts of at least one of the above compounds in addition to conventional excipients and/or carriers. The compositions of the Invention can be administered by the oral, parenteral, rectal or topical route, for instance in form of tablets, capsules, syrups, sachets, solutions, vials, bottles, suppositories.

The doses will be dependent on the patient's weight, age and conditions and will be anyhow ranging from 50 to 1000 mg, from 1 to 4 times a day.