ACYLAMINO-ALKYLIDEN-HYDROXY-BISPHOSPHONIC ACIDS USEFUL IN THE THERAPY OF OSTEOARTICULAR DISEASES

Abstract: Hydroxydiphosphonic acids of general formula (I), a process for the preparation thereof and the use thereof in anti-inflammatory therapy.

Description: Acylam1no-al kyl 1den-hydroxy-b1 sphosphon1c adds useful 1n the therapy of osteoartlcular di seases. The present invention relates to compounds of ge¬ neral formula ( I ) wherein A is a _ ( CH 2^~n 9 rou P with n comprised between 1 and 10; R is an acyl residue from a known anti-inflammatory compound belonging in the class of salicylic, arylace- tic, arylpropionic, anthranylic, 4,5-dihydroxy- or 4,5,8-trihydroxy-9,10-dihydro-9,10-dioxo-2-anthracene- carboxylic, nicotinic acids. Examples of known anti-inflammatory acids, the acyl residues of which form the R group, as defined in formula (I), are reported hereinbelow: salicylic acids: salicylic acid, acetylsalicylic acid, 5-aminosalicylic acid, diflunisal, fendosal; arylacetic acids: acemetacin, alclofenac, a fenac, ben- zadac, bufexa ac, bumadizone, cinmetacin, clidanac, clometacin, clopirac, diclofenac, etodolac, fenclofe- nac, indobufen, indometacin, methiazinic acid, sulin- dac, tolmetin, zomepirac; propionic acids: alminoprofen, benoxaprofen, bucloxic acid, carprofen, flurbiprofen, ibuprofen, ketoprofen, loxoprofen, naproxen, oxaprozin, protizinic acid, pi- neprofen, pirprofen, pranoprofen, suprofen, thiaprofe- nic acid; anthranylic acids: flufenamic acid, meclofenamic acid, mefenamic acid, niflumic acid, lobenzarit, tolfenamic acid; 4,5-dihydroxy- or 4,5,8-trihydroxy-9,10-dihydro-9,10- dioxo-2-anthracenecarboxylic acids: diacerhein, thio- r ein. Particularly preferred are the compounds of for¬ mula (I) wherein R is 2-acetoxybenzoyl, the residues from diflunisal, ibufenac, ibuprofen, naproxen, indome- tacin, diacerhein. Most preferred compounds are those in which n is 3 or 5. In case the residue R contains one or more chiral carbon atoms, the invention comprises the single enan- tiomers and the mixtures of racemates and of diastereoisomers thereof. The invention also relates to the diphosphonic acid salts, the esters of both the phosphonic groups and the hydroxy group, with the proviso that they are pharmaceutically acceptable. The compounds of formula (I) derive from the con¬ densation of known anti-inflammatory compounds with known UJ-aminoalkylene-l-hydroxy-l,l-diphosphonic acid derivatives already used in therapy due to their inhi¬ biting action on bone resorption and antiurolithiasic action. CU-Aminoalkylene-l-hydroxy-1,1-diphosphonic acids are described in Italian Patent Applications N. 22047A/88 and 1274A/89 and in German Patent Applica¬ tions N. DE-OS 2,534,391 and DE-OS 3,540,150. Alkyl-l-hydroxy-l , l-diphosphonic acid derivatives condensed with anti-inflammatory residues through a C-C bond are known from EP-A-84822. The compounds of the invention , on the contrary, are characterized by an amido bond between the a ino group of the J_aminoalkylenehydroxydiphosphonic acid and the carboxy group of the anti-inflammatory compound. Contrarily to what could be assumed, the pharmaco- logical properties of the compounds of formula (I) are not those typical of "pro-drugs" which can release "in vivo" the two components which independently carry on their therapeutical activities. In fact, it has surprisingly been found that com- pounds (I) have a far higher anti-inflammatory activity than the one which could be assigned to the "in vivo" release of a known RCOOH pharmacologically active acid. This is even more surprising in that the aminoalkylhy- droxydiphosphonic component is completely devoid of anti-inflammatory activity. Compounds of formula (I) are prepared by reacting a compound of formula (II) wherein A has the above mentioned meaning, with a com¬ pound of formula RCOOH, wherein R is as defined above, or with a reactive derivative thereof (chloride, anhy¬ dride, imidazolide etc.). The reaction is preferably carried out in an aqueous medium in the presence of alkali, using a reactive derivative of the carboxy group of the R molecule, such as the acid chloride. The advantageous properties of the compounds of the invention make them useful in the therapy of mu- scle-skeletal apparatus disorders. Therefore, the compounds of the invention will be used for the preparation of pharmaceutical compositions in admixture with suitable excipients and/or other drugs which can adjuvate the therapeutic action. Examples of said pharmaceutical compositions com¬ prise both solid and liquid oral formulations, optionally in sustained-release or gastro-resistant forms, injectable formulations, optionally in depot forms, suppositories and topical forms. The posology will be determined according to the pathology and patient's conditions (age, sex, weight) and the clinician's prescriptions. Dosage forms could be unit forms containing 2 to 500 mg of the active ingredient per unit dose. The following examples further illustrate the in¬ vention. EXAMPLE 1 [4-(2-Acetoxybenzoyl)-amino-1-hydroxybutylidene]-dipho- sphonic acid 3.18 g (9.8 moles) of sodium trihydrogen 4-amino- 1-hydroxybutylidenediphosphonate trihydrate are added in 30 ml of water to 1.8 g (45 mmoles) of sodium hydro¬ xide, 100 mg of p-dimethylaminopyridine and 200 mg of tetrahexylammonium iodide. The resulting solution is cooled to 0°C, and added with 2.03 g (10.2 mmoles) of 2-acetoxybenzoic acid chloride dissolved in 10 ml of diethyl ether. The reaction mixture is stirred for 2 hours at room temperature, then it is extracted with ethyl ether and the aqueous solution is acidified with concentrated HC1 under stirring, with cooling. [4-(2- Hydroxybenzoyl)-amino-1-hydroxybutylidene]-diphosphonic acid precipitates, which is filtered, washed and dried at 70°C and transformed into the title product by means of acetylation with acetic anhydride. M.P. (dec.) > 150°C E.A. for c i3 H 1 9 NO 10 P 2 theoretic % found % C 37.96 38.04 H 4.65 4.69 N 3.40 3.45 I.R. and 1H N.M.R. in conformity. EXAMPLE 2 [6-(2-Acetoxybenzoyl)-amino-1-hydroxyhexylidene]-dipho¬ sphonic acid The procedure of example 1 is followed, but using 3.45 g (9.8 mmoles) of sodium trihydrogen 6-amino-l- hydroxyhexylidenediphosphonate trihydrate. [6-(2-Hydroxybenzoyl)-amino-1-hydroxyhexylidene]- diphosphonic acid precipitates. The procedure of exam¬ ple 1 is repeated, to obtain the title product, having the following characteristics: M.P. (dec.) > 150°C E.A. for C 15 H 23 NO 10 P 2 theoretic % found % C 41.00 40.94 H 5.27 5.23 N 3.18 3.24 .R. and 1H N.M.R. in conformity. EXAMPLE 3 [4-[5-(2 ,4-Difluorophenyl)-2-hydroxybenzoyl]-amino-1- hydroxybutylideneI-diphosphonic acid The procedure of example 1 is repeated, using 3.18 g (10.2 mmoles) of 5-(2,4-difluorophenyl)-2-acetoxyben- zoic acid chloride. After acidification with concentrated HC1, the ti¬ tle product precipitates, having the following characteristics: M.P. (dec) > 150°C E.A. for C 17 H ιg F 2 N0 9 P 2 theoretic % found % C 42.41 42.36 H 3.97 3.94 N 2.90 2.98 I.R. and 1H N.M.R. in conformity. Analogously to the above examples, the following compounds have been prepared: EXAMPLE 4 [ 6-[5-(2,4-Difluorophenyl)-2-hydroxybenzoyl3-amino-1- hydroxyhexylidene]-diphosphonic acid M.P. (dec) > 150°C E.A.. for C, 9 H 23 F 2 N0 9 P 2 theoretic % found % C 44.80 44.85 H 4.55 4.58 N 2.74 2.80 I.R. and 1H N.M.R. in conformity. EXAMPLE 5 [4-(4-Isobutylphenyl)-acetylamino-1-hydroxybutylidene3- diphosphonic acid M.P. (dec) > 150°C E.A. for C 16 H 27 NO g P 2 theoretic % found % C 45.38 45.44 H 6.42 6.47 N 3.30 3.36 I.R. and H N.M.R. in conformity. EXAMPLE 6 [6-(4-Isobutylphenyl)-acetylamino-1-hydroxyhexylidene3■ diphosphonic acid M.P. (dec) > 150°C E.A. for C 18 H 31 N0 8 P 2 M.P. (dec) > 150°C E.A. for C 17 H 29 N0 8 P 2 M.P. (dec) > 150°C E. A . for c 1 q H 33 N0 8 P 2 [4-[2-(6-Methoxynaphthyl)-propionyl3-amino-1-hydroxybu- tylidene3 -diphosphonic acid M.P. (dec) > 150°C E. A . for c τ_3 H 25 N0 9 P 2 [6-[2-(β-Methoxynaphthyl)-propionyl3-amino-1-hydroxyhe- xylidene3-diphosphonic acid M.P. (dec) > 150 β C E.A. for C 20 H 2g NO 9 P 2 M.P. (dec) 150°C E.A. for C 23 H 27 ClN 2 O 10 P 2 theoretic % found % C 46.90 46.99 H 4.62 4.66 N 4.75 4.68 I.R. and 1H N.M.R. in conformity. EXAMPLE 12 [6-[1-(4-Chlorobenzoyl)-2-methyl-5-methoxy-2-indolyl]- acetyl-amino-1-hydroxyhexylidene3-diphosphonic acid M.P. (dec) > 150°C E.A. for C 25 H 31 ClN 2 O 10 P 2 theoretic % found % C 48.66 H 5.06 N 4.53 I.R. and 1H N.M.R. in conformity. EXAMPLE 13 Carrageenin oedema in rat Used substances: Carrageenin (control -) Carrageenin + Ibuprofen (11 and 5.5 mg/kg) Carrageenin + compound of example 8 (Br-Aex) (25.0 and 12.5 mg/kg) Carrageenin + compound of example 7 (Br-Ab) (25.0 and 12.5 mg/kg) Note: Ibuprofen doses are equimolar to the corre¬ sponding Br-Ab and Br-Aex doses. Used animals: S.D. male rats weighing 160 - 180 g Test groups: 1) Control - (Carrageenin only) 2) Ibuprofen 11.0 mg/kg 3) Ibuprofen 5.5 mg/kg 4) Br-Ab 25.0 mg/kg 5) Br-Ab 12.5 mg/kg 6) Br-Aex 25.0 mg/kg 7) Br-Aex 12.5 mg/kg Each group consisted of 5 males, trying to obtain the most homogeneous total weight for each group. The animals were inoculated subcutaneously with the test solutions homogenized in 5% gum Arabic which had been sterilized by filtration with "Acrodisc" Gelman with 0.45 μl pores. After 1 hour the animals were slightly anaestheti¬ zed with 0.1 ml of 1% carrageenin in sterile saline. Carrageenin was kept under stirring by means of a ma- gnetic stirred, to make it as homogeneous as possible. At the same time, the basal paw volumes were de¬ termined by means of a plethysmograph, so as to make possible to repeat the measurements in the most relia¬ ble way in the subsequent hours. 2 Hours after carrageenin inoculation, the measure of paw volumes was determined (2nd hour). Subsequently, said measurement was effected at the 4th and 6th hours from inoculation. After that, the % protection was calculated by means of the following formula: Increase in paw volume of the treated group x 100 = A Increase of paw volume in control group 100 - A = % Protection Table 1 (% Protection) The obtained results show that all of the com¬ pounds of the invention give a higher protection than one of Ibuprofen; moreover, pharmacological differences exist among the compounds of the invention due to the methylene portion length (A in general formula) . EXAMPLE 14 Male rats weighing about 200 mg are thyroparathy- roidectomyzed under Nembutal anaesthesia. The animals are treated with thyroxine on alternate days during all the test. 7 Days after surgery, blood is withdrawn by means of intracardiac puncture and Ca is determined on plasma. The animals with a Ca plasma content higher than 2 mM are excluded from the test, the others are treated with the compounds under test and with retinoid which is administered subcutaneously for 3 consecutive days. 24 Hours after the last administration, animals are killed and blood is recovered to determine Ca again. Table 2 EFFECT OF BR-AB AND BR-AX DERIVATIVES ON BONE CALCIUM LOSS INDUCED BY RETINOID IN RAT Compound Plasmatic Ca increase % inhibition after retinoid adm. (mmol/lt) Controls 1.11 ± 0.03 AHBuBP 0.29 ± 0.2 73.9 BRU-AB 0.62 ± 0.03 44.1 BRU-AX 0.75 + 0.17 32.4

Claims: CLAIMS 1. Compounds of general formula (I) R-NH-A-C-OH (I) P0 3 H 2 wherein A is a -( CH 2^~n 9 rou P w i- tn n comprised between 1 and 10; R is an acyl residue from a known anti-inflammatory compound belonging in the class of salicylic, arylace- tic, arylpropionic, anthranylic, 4 ,5-dihydroxy- or 4,5,8-trihydroxy-9,10-dihydro-9,10-dioxo-2-anthracene- carboxylic, nicotinic acids. 2. Compounds according to claim 1, wherein A is as defined above and R is one of the acyl residues from the following compounds: salicylic acid, acetylsalicy¬ lic acid, 5-aminosalicylic acid, diflunisal, fendosal, acemetacin, alclofenac, amfenac, benzadac, bufexamac, bumadizone, cinmetacin, clidanac, clometacin, clopirac, diclofenac, etodolac, fenclofenac, indobufen, indometa- cin, methiazinic acid, sulindac, tolmetin, zomepirac, alminoprofen, benoxaprofen, bucloxic acid, carprofen, flurbiprofen, ibuprofen, ketoprofen, loxoprofen, na- proxen, oxaprozin, protizinic acid, pineprofen, pir- profen, pranoprofen, suprofen, thiaprofenic acid, flu- fenamic acid, meclofenamic acid, mefenamic acid, niflumic acid, lobenzarit, tolfenamic acid, diacerhein, thiorhein. 3. Compounds according to claims 1-2, wherein A is as defined above, R is 2-acetoxybenzoyl, the residues from diflunisal, ibufenac, ibuprofen; naproxen; indometacin; diacerhein. 4. Compounds according to claims 1-3, wherein A is -(CH-,)-.- or -(CH_) -, and R is as defined in claim 3. 5. A process for the preparation of compounds of for¬ mula I, characterized in that a compound of formula R- COOH is reacted with a compound of formula (II) 6. A process for the preparation of compounds of for¬ mula I according to claim 4, characterized in that R- COOH acid chloride is reacted with compound of formula (ID 7. The use of compounds of claims 1-4 as therapeuti¬ cal agents. 8. Pharmaceutical compositions containing as the ac¬ tive ingredients the compounds of claims 1-3 in admix¬ ture with pharmaceutically acceptable carriers and di¬ luents. 9. The use of compounds of claims 1-3, for the prepa- ration of a medicament for the treatment of osteoarti- cular and connective tissue disorders.

Inventors: MIAN MAURIZIO, ROSINI SERGIO, MIAN, MAURIZIO, ROSINI, SERGIO
Applicants: GENTILI IST SPA, ISTITUTO GENTILI S.P.A.
Application year: 1992
Main classification: C07F9
IPC codes: A61K31, A61P3, A61P19, A61P29, A61P43, C07F9