HYDROXYPROLINE DERIVATIVE, A PROCESS FOR THE PREPARATION THEREOF AND PHARMACEUTICAL COMPOSITIONS CONTAINING IT

Abstract: 4-(Thiophene-2-carbonyl)-oxypyrrolidine-2-carboxylic acid of formula (I) and the salts thereof with pharmaceutically acceptable acids or bases, a process for the preparation thereof and the use thereof for the preparation of a medicament having anti-inflammatory and antidystrophic activities are disclosed.

Description: HYDROXYPROLINE DERIVATIVE, A PROCESS FOR THE PREPARA¬ TION THEREOF AND PHARMACEUTICAL COMPOSITIONS CONTAINING IT The present invention relates to 4-(thiophene-2- carbonyl)-oxypyrrolidine-2-carboxylic acid, of formula I H I and to the salts thereof with pharmaceutically accepta¬ ble acids or bases. The present invention also relates to a process for the preparation of compound I as well as to the pharmaceutical compositions containing it as the active ingredient. Examples of pharmaceutically acceptable salts are the hydrochloride, sulfate, citrate, tar- trate, p-toluenesulphonate salts as well as the sodium, potassium, calcium, magnesium, ammonium, triethylammo- nium salts and the like. N-acetyl-hydroxyproline is an amino acid already used in therapy due to its cutis healing and eutrophi- zing activities and anti-inflammatory activity. Now it has been found that compound I remarkably improves the pharmacological and pharmacokinetic cha¬ racteristics of the N-acetyl derivative cited above. Therefore, another object of the present invention is provided by pharmaceutical compositions containing compound of formula I or a salt thereof in admixture with suitable carriers. The compositions of the inven¬ tion can be used by the oral, parenteral or topical routes, for the treatment of a variety of diseases due to inflammatory and dystrophic conditions, such as ar- throsis, der atosclerosis, dystrophic vaginitis, skin and mucosa sores or ulcerations, and the like. Examples of pharmaceutical formulations comprise capsules, tablets, drinkable solutions, syrups, vaginal suppositories, creams, suppositories, containing 1 to 10% active ingredient or unitary doses from 100 to 500 mg. The daily dosage will depend upon a number of fac¬ tors, but generally it will range from 100 to 1000 mg daily, in one or more administrations. Compound I is prepared by reacting hydroxyproline, previously suitably protected at the pyrrolidine nitro¬ gen atom, with a reactive derivative of 2-thiophenecar- boxylic acid, according to conventional procedures. The following example further illustrates the in¬ vention. EXAMPLE a) 6.55 g (0.05 mole) of (L)-4-hydroxyproline are added to a 1M NaOH solution (NaOH 2.2 g; 0.055 mole in 55 ml of water). A solution of 10.9 g (0.05 mole) of di-tert-butyl dicarbonate in 20 ml of t-butanol is slo¬ wly dropped into the above solution (the reaction is slowly exothermic). The reaction mixture is left to react at room temperature under stirring for 18 hours. t-Butanol is evaporated off without exceeding 30°C. The remained aσueous solution is cooled to 0-5°C and acidified to pH = 1-1.5 by adding a solution of 11.3 g (0.0825 mole) of KHS0 4 in 75 ml of water : C0 2 development takes place. The solution is extracted with 3 x 20 ml of ethyl ether. The ether extracts are dried over a 2 SO. and evaporated, to obtain the 4- hydroxyproline protected derivative (A) as a colourless solid. Yield : 9.2 g (80%). m.p. : 120°C (lit. 134 β C). N.M.R. (D 2 0) : in conformity. b) A mixture of 10 g (0.078 mole) of 2-thiophene- carboxylic acid and 30 ml of thionyl chloride is re- fluxed for a night; then thionyl chloride is evaporated off and the residue is distilled in Vigreux under redu¬ ced pressure : T = 128-130°C; P = 190 mmHg 2-Thiophenecarboxylic acid chloride (B) is obtained; yield : 9.06 g (79%). c) 8.5 g (0.0368 mole) of product (A) are dissol¬ ved in 18 ml of 10% NaOH. The solution is cooled to 0°C and a solution of 5.93 g (0.0368 mole) of product (B) in 5 ml of dioxane is dropped therein, then 18 ml of 10% NaOH, keeping the same temperature. When the addi¬ tions are completed, the reaction mixture is left to warm to room temperature and to react overnight, then it is acidified to pH 4 with concentrated hydrochloric acid and extracted with ethyl ether. The extract is dried over Na_S0. and evaporated, the obtained viscous residue (11.5 g) is subjected to chromatography on 200 g of silica gel, using a dioxane/toluene/acetic acid 10:45:2 mixture as the eluent, to separate the desired product (C) (having R f = 0.4) from unreacted 2- thiophenecarboxylic acid (having R f = 0.5). 9.17 g of a glassy residue are obtained, which consists of (C) and, to a small extent, of 2-thiophene- carboxylic acid, which is used directly. A small amount is treated with n-hexane/diiso- propyl ether 10:1, to obtain (C) as a colourless solid. Yield : 9.17 g (73%); m.p. 129-131°C; T.L.C. : (toluene/dioxane/acetic acid = 10:45:2); unitary,. R f = 20 0.4; [<X] D = -47.4° (C = 1, CH 3 OH) ; N.M.R. (CDClg) : in conformity. d) 8.32 g (0.0244 mole) of (C) are dissolved in 10 ml of anhydrous tetrahydrofuran, then 35 ml of 3.9 HCl in THF (equivalent to 0.0244 x 5 mole) are added the¬ reto. The reaction mixture is left to react at room temperature overnight, with stirring. Since T.L.C. checking proves that the reaction is not completed, 10 ml more of 3.9 M HCl in THF are added, and the mixture is left to react for 7 hours more. The reaction pro¬ ceeds but it is not still completed : 5 ml of 3.9M HCl in THF are added and the mixture is left to react for 15 hours until the reaction is completed. Solvent is evaporated off and the solid colourless residue is taken up into ethyl ether (in which 2-dodecenecarboxy- lic -acid is soluble) and filtered. The hydrochloride of the compound is obtained, in form of a colourless solid. Yield : 5.46 g (81%); m.p. 248-250°C (the product becomes dark). T.L.C. : (eluent : toluene/dioxane/AcOH = 10/45/2) : unitary. ^ 20 PX] D : -r 2.4° (c = 0,5 CH 3 OH) - I . R. (nujol ) : 1700 cm -1 -COOH - elemental analysis (for C, Q H, 2 C1N0.S) % calc. C 43.24 H 4.32 N 5.05 % found C 43.13 H 4.26 N 5.18 - NMR (DMSO) 8 ppm: 2.4-2.6 (m, 2H) ; 3.3-3.8 (m, 2H) ; 4.4-4.6 (d,d IH); 5.5 (m, IH) ; 7.2 (t, IH) ; 7.9-8.1 (m, 2H); 10-11 (broad) (2H). The signal at 10-11 8 disappears upon deuteration with D 2 0.

Claims: CLAIMS 1. 4-(Thiophene-2-carbonyl)-oxypyrrolidine-2-carboxy- lic acid of formula I H and the salts thereof with pharmaceutically acceptable acids or bases. 2. As a compound as claimed in claim 1, the hydro- chloride of compound I. 3. A process for the preparation of compound I, in which 4-hydroxyproline, having the pyrrolidine nitrogen atom protected, is reacted with a reactive derivative of 2-thiophenecarboxylic acid. 4. Pharmaceutical compositions containing a compound as claimed in claims 1-2 as the active ingredient, to¬ gether with pharmaceutically acceptable carriers and/or excipients. 5. The use of a compound as claimed in claims 1-2 for the preparation of a medicament having anti-inflam¬ matory and antidystrophic activities.

Inventors: RAINOLDI ANGELO, RAINOLDI, ANGELO
Applicants: PULITZER ITALIANA, PULITZER ITALIANA S.R.L.
Application year: 1991
Main classification: C07D409
IPC codes: C07D409