9-N-ethenyl derivatives of 9(S)-erythromycylamine

Abstract: The invention relates to 9- N -ethenyl derivatives of 9( S )-erythromycylamine, new semisynthetic antibiotics of the macrolide class of the general formula (I) wherein R 1 and R 2 are the same or different and represent nitryl, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, to their pharmaceutically acceptable addition salts with inorganic or organic acids, to a process for their preparation, to a process for the preparation of the pharmaceutical compositions as well as to the use of the obtained pharmaceutical compositions in the treatment of bacterial infections.

Description: The present invention relates to 9-N-ethenyl derivatives of 9(S)- erythromycylamine, novel semisynthetic antibiotics of the macrolide class having antibacterial action, of the general formula (I) wherein R 1 represents a cyano group, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and wherein R 2 represents a cyano group or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, their pharmaceutically acceptable addition salts with inorganic or organic acids, to a process for the preparation thereof, to a process for the preparation of pharmaceutical compositions. Erythromycin A is a macrolide antibiotic, whose structure is characterized by a 14-member macrolactone ring having a carbonyl group in C-9 position. It was found by McGuire in 1952 (Antibiot. Chemother., 1952; 2:281) and for over 40 years it has been considered as a reliable and effective antimicrobial agent in the treatment of diseases caused by gram-positive and some gram-negative microorganisms. However, in an acidic medium it is easily converted into anhydroerythromycin, an inactive C-6/C-12 metabolite of a spiroketal structure (Kurath P. et al., Experientia 1971; 27:362). It is well-known that spirocyclisation of the aglycone ring of erythromycin A is successfully inhibited by a chemical transformation of C-9 ketones or of hydroxy groups in C-6 and/or C-12 positions. By the oximation of C-9 ketones (D jokic ′ S. et al., Tetrahedron Lett., 1967; 1945) and by subsequently modifying the obtained 9( E )-oxime into 9-[O-(2-methoxyethoxy)-methyloxime] erythromycin A (ROXITHROMYCIN) (Ambrieres, G.S., FR 2,473,525/1981) or 9( S )-erithromycylamine (Egan R. S. et al., J. Org. Chem., 1974; 39:2492) or a more complex oxazine derivative thereof, 9-deoxo-11-deoxy-9,11-{imino[2-(2-methoxyethoxyethylidene]-oxy}-9( S )-erythromycin A (DIRITHROMYCIN) (Lugar P. et al., J. Crist. Mol. Struct., 1979; 9:329), novel semisynthetic macrolides were synthetized, whose basic characteristic, in addition to a greater stability in an acidic medium, is better pharmacokinetics and a longer biological half-life with regard to the parent antibiotic erythromycin A. The first successful synthesis of erythromycylamine by catalytical reduction of erythromycin oxime in glacial acetic acid with platinum oxide was performed by Massey et al. (Tetrahedron Lett., 1970; 157) and beside 9( S )-isomer also the less active 9( R )-isomer (Massey E.H. et al., J.Med.Chem., 1974; 17: 105) was obtained. Kobrehel et al. (J.Med.Chem., 1978; 13: 83) synthesized a series of N -substituted benzensulfonylerythromycylamines. 11,12-cyclic carbonates (Boyarska-Dahlig H. et al., Pol.J.Chem., 1979; 53: 2551; Sciavolino F.C., US patent 4,283,527/1982) were prepared by treating erythromycylamine with ethylene carbonate via a previous protection of 9( S )-amino group. By the synthesis of peptide erythromycylamine (LeMahieu R.A. et al., J.Antib., 1982; 35: 10631) erythromycylamine derivatives without any antibiotic activity were obtained. Most research on erythromycylamine has included the reaction of erythromycylamine with aldehydes and ketones, whereat condensation products (Massey E.H. et al., J.Med.Chem., 1974; 17; 105) or 9- N -, 11- O -oxazine derivatives (Maier R. et al., US patent 4,048,306/1977) were obtained. By the reduction of the condensation product with NaBH 4 , 9- N -alkyl or 9- N -benzyl derivatives (Wildsmith E. et al, J.Med.Chem., 1973; 16: 1059) were formed, 9- N ,11-- O -oxazine derivatives, which are not reducible, being an exception. Photoactive erythromycylamine derivatives were prepared in the year 1989 by coupling photoreactive groups to erythromycylamine (Arevalo M.A. et al., J.Med.Chem., 1989; 3: 2200). In addition also a number of Schiff's bases of erythromycylamine were prepared (Aries R., FR appln. 2311029-1976; Ewans D., GB patent 1,345,524/1974; Werner R.G. et al., Biochem. Biophys. Res. Commun. , 1978; 83: 1147) . DE-OS 2 515 076 discloses new erythromycine derivatives of the general formula I, wherein R 1 represents an alkyl group having 1 to 4 C-atoms, an alkyl group having 1 to 4 C-atoms substituted with a dialkylamino group having 1 to 3 C-atoms or with a benzyloxy group, or a benzyl group. R 2 represents an alkoxy group having 1 to 4 C-a toms which can optionally be substituted with a methoxy, benzyloxy or dimethylamino group, an alkoxycarbonyl group having 1 to 4 C-atoms in the alkyl portion or a benzyloxycarbonyl group; a phenoxy group or a benzyloxy group, an amino group of the general formula -NR 3 R 4 , wherein R 3 and R 4 , which can be the same or different, represent alkyl groups having 1 to 4 C-atoms or wherein R 3 and R 4 together with the N-atom inbetween form a pyrrolidino-, piperidino-, morpholino-, thiomorpholino-, 1-oxo-thiomorpholino-, 1.1-dioxo-thiomorpholino- or N-methylpiperazino-group, an amido group of the general formula -NH-CO-R 5 , wherein R 5 represents a H-atom, an alkyl group having 1 to 5 C-atoms or a phenyl residue, the phenyl residue optionally being substituted with one or more methyl- or methoxy groups or halogen atoms, and E represents a erythromycyl group of formula and the physiologically acceptable acid addition salts thereof with inorganic or organic acids. It has been found and it is an object of the present invention that novel 9- N -ethenyl derivatives of 9-( S )-erythromycylamine and pharmaceutically acceptable addition salts thereof with inorganic or organic acids may be prepared by reacting 9-( S )-erythromycylamine with substituted ethoxyethylene derivatives and, if appropriate, by reacting the obtained 9- N -ethenyl derivatives of 9-( S )-erythromycylamine with inorganic or organic acids. It has been found that the present 9- N -ethenyl derivatives of 9-( S )-erythromycylamine of the general formula (I) wherein R 1 represents a cyano group, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and wherein R 2 represents a cyano group or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group and their pharmaceutically acceptable addition salts with inorganic or organic acids can be prepared by reacting 9-(S)-erythromycylamine of the formula (II) with ethoxyethylene derivatives of the general formula (III) wherein R 1 represents a cyano group, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group. and wherein R 2 represents a cyano group or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group. The reaction is carried out in toluene, xylene or some other aprotic solvent at a temperature from 20 ° to 80 °C. Pharmaceutically acceptable addition salts, which are also an object of the present invention, are obtained by the reaction of 9-N-ethenyl derivatives of 9-(S)-erythromycylamine with an equimolar amount of an appropriate inorganic or organic acid such as hydrochloric acid, hydroiodic acid, sulfuric acid, phosphoric acid, acetic acid, trifluoroacetic acid, propionic acid, benzoic acid, benzene sulfonic acid, methane sulfonic acid, lauryl sulfonic acid, stearic acid, palmitic acid, succinic acid, ethylsuccinic acid, lactobionic acid, oxalic acid, salicylic acid and similar acids, in a solvent inert to the reaction. Compounds of the general formula (I), wherein R 1 , R 2 , R 3 and R 4 have the meanings as defined hereinbefore demonstrate antibacterial in vitro action and their action spectrum is similar to the one of erythromycin. Hence they can be used for the same purpose and in the same manner as erythromycin A. In general, compounds of the general formula (I) demonstrate in vitro action against Gram-positive microorganisms such as Streptococcus faecalis ATCC 8043, S. epidermidis ATCC 12228 and Staphylococcus aureus ATCC 6538. Their action is determined by the method of the dilution on microplates according to the protocol of the National Commitee for Clinical laboratory Standards (NCCLS, M7-A2). The obtained results expressed as MIC in µg/ml suggest a potential use thereof as sterilisation agents of e.g. rooms and medical instruments and as industrial microbial agents e.g for the protection of wall and wooden coatings. The process for the preparation of 9- N -ethenyl derivatives of 9-( S )-erythromycylamine is illustrated by the following Examples: Comparative EXAMPLE 9( S )- N- (β,β-Dicarbethoxyethenyl)erythromycylamine A mixture of 9( S )-erythromycylamine (1.0 g; 1.36 mmol) and diethyl ethoxymethylenemalonate (3.2 ml; 16.0 mmol) was heated under reflux for 90 minutes. To the reaction mixture cooled to a temperature of 0-5°C diethylether (14 ml) was added and the obtained suspension was stirred for 15 minutes at the same temperature and for further 15 minutes at room temperature. 0.480 g of 9 ( S ) -N- ( β,β -dicarbethoxyethenyl)erythromycylamine were obtained. The sample for analysis and biological investigation was purified by chromatography over a silica gel column in a solvent system CHCl 3 :MeOH = 9:1 yielding 0.27 g of 9( S )- N -(β,β-dicarbethoxyethenyl)erythromycylamine with the following physical-chemical constants: IR (CHCl 3 ) cm -1 : 3500, 2950, 1725, 1670, 1600, 1450, 1380, 1250, 1225, 1170, 1080; 1 H NMR (300 MHz, CDCl 3 ) δ: 9.55 (1H, 9- NH -CH), 7.79 (9-NH- CH =C), 5.09 (1H, H-1", 4.65 (1H, H-1'), 4.23 (-COO CH 2 CH 3 ), 4.22 (1H, H-3), 4.17 (-COO CH 2 CH 3 ), 3.35 (1H, H-5), 3.34 (3H, 3"-OCH 3 ), 3.28 (1H, H-2'), 3.06 (1H, H-4"), 2.65 (1H, H-9), 2.31 6H, 3'-N(CH 3 ) 2 ], 2.26 (1H, H-10), 1.96 (1H, H-8), 1.32 and 1.28 (-COOCH 2 CH 3 ), 1.16 (3H, 8-CH 3 ), 1.06 (3H, 10-CH 3 ); 13 C NMR (75 MHz, CDCl 3 ) δ: 177.7 (C-1), 168.7 (- CO OCH 2 CH 3 ), 166.7 (- CO OCH 2 CH 3 ), 160.2 (9-NH- CH =C), 132.2 (9-NH-CH=C), 102.2 (C-1'), 95.7 (C-1"), 81.5 (C-5), 79.4 (C-3), 59.2 (-COO CH 2 CH 3 ), 59.1 (-COO CH 2 CH 3 ), 77.3 (C-4"), 70.5 (C-2'), 74.7 (C-9), 48.9 (3"-OCH 3 ), 40.0 [3'-N(CH 3 ) 2 ], 32.3 (C-10), 32.3 (C-8), 18.3 (8-CH 3 ), 14.1 (-COOCH 2 CH 3 ), 13.9 (-COOCH 2 CH 3 ), 13.0 (10-CH 3 ); FAB-MS m/z 906 (M + H) + . EXAMPLE 1 9( S )- N -(β-Cyano-β-carbethoxyethenyl)erythromycylamine A mixture of 9( S )-erythromycylamine (0.5 g; 0.68 mmol) and ethyl ethoxymethylenecyanoacetate (0.2 g; 1.18 mmol) in toluene (20 ml) was heated under reflux within 60 minutes. The reaction mixture was then chilled and evaporated to dryness. The obtained yellow crystals of a crude product (0.5 g) were purified by chromatography over a silica gel column by the use of solvent system EtOAc:Me 2 CO = 1:1 yielding 0.14 g of 9( S )- N -(β-cyano-β-carbethoxyethenyl)erythromycylamine with the following physical-chemical constants: IR (CHCl 3 ) cm -1 : 3500, 2950, 2200, 1730, 1675, 1625, 1450, 1380, 1250, 1225, 1170, 1080; 1 H NMR (300 MHz, CDCl 3 ) δ: 9.46 (1H, 9- NH -CH), 7.05 (9-NH- CH =C), 5.07 (1H, H-1"), 4.61 (1H, H-1'), 4.22 (1H, H-3), 4.19 (-COO CH 2 CH 3 ), 3.76 (1H, H-5), 3.34 (3H, 3"-OCH 3 ), 3.25 (1H, H-2'), 2.29 [6H, 3'-N(CH 3 ) 2 ], 2.20 (1H, H-10), 1.96 (1H, H-8), 1.31 -COOCH 2 CH 3 ), 1.14 (3H, 8-CH 3 ), 1.05 (3H, 10-CH 3 ); 13 C NMR (75 MHz, CDCl 3 ) δ: 177.5 (C-1), 167.6 (- CO OCH 2 CH 3 ), 159.1 (9-NH-CH=C), 119.4 (-CN), 117.5 (9-NH-CH= C ), 101.7 (C-1'), 95.2 (C-1"), 80.8 (C-5), 78.9 (C-3), 60.1 (-COO CH 2 CH 3 ), 77.5 (C-4"), 70.7 (C-2"), 75.5 (C-9), 49.1 (3"-OCH 3 ), 40.1 [3'-N(CH 3 ) 2 ], 32.1 (C-10), 32.7 (C-8), 18.4 (8-CH 3 ), 14.2 (-COOCH 2 CH 3 ), 13.2 (10-CH 3 ); FAB-MS m/z 858 (M+H) + . EXAMPLE 2 9 ( S ) -N- (β,β-Diacetylethenyl)erythromycylamine According to the process described in Example 1, by the reaction of 9( S )-erythromycylamine (0.5 g; 0.68 mmol) and ethoxymethyleneacetylacetone (1.0 ml; 6.88 mmol) in toluene (20 ml) under heating for 90 minutes at a temperature of 50°C 0.54 g of a crude product were obtained. By chromatography over silica gel column using the solvent system EtOAc:Me 2 CO = 1:1 there were obtained 0.21 g of 9( S ) -N -(β,β-diacetylethenyl)erythromycylamine with the following physical-chemical constants: IR (CHCl 3 ) cm -1 : 3500, 2950, 1725, 1610, 1550, 1450, 1375, 1320, 1170, 1080; 1 H NMR (300 MHz, CDCl 3 ) δ: 10.89 (1H, 9- NH -CH), 5.14 (1H, H-1"), 4.71 (1H, H-1'), 3.84 (1H, H-3), 3.70 (1H, H-5), 3.35 (3H, 3"-OCH 3 ), 3.30 (1H, H-2'), 2.31 [6H, 3'-N(CH 3 ) 2 ], 2.21 (1H, H-10), 1.99 (1H, H-8), 1.96 (3H, -CO CH 3 ), 1.87 (3H, -CO CH 3 ), 1.20 (3H, 8-CH 3 ), 1.06 (3H, 10-CH 3 ); 13 C NMR (75 MHz, CDCl 3 ) δ: 193.4 (- CO CH 3 ), 176.8 (C-1), 163.1 (9-NH-CH= C ), 101.9 (C-1'), 95.2 (C-1"), 79.1 (C-5), 78.2 (C-3), 77.6 (C-4"), 70.7 (C-2'), 65.5 (C-9), 48.9 (3"-OCH 3 ), 40.0 [3'N(CH 3 ) 2 ], 32.9 (C-10), 33.4 (C-8), 28.2 (-CO CH 3 ), 19.1 (-CO CH 3 ), 18.3 (8-CH 3 ), 12.5 (10-CH 3 ). EXAMPLE 3 9( S )- N -(β,β-Dicyanoethenyl)erythromycylamine A mixture of 9( S )-erythromycylamine (0.5 g; 0.68 mmol) and ethoxymethylenemalonedinitrile (0.18 g; 1.47 mmol) in toluene (20 ml) was stirred at a room temperature for about 30 minutes. The cooled reaction mixture was evaporated and the obtained yellow crystals (0.65 g) were purified by chromatography over a silica gel column using the solvent system CHCl 3 :MeOH = 9:1 yielding 0.26 g of 9( S )- N -(β,β-dicyanoethenyl)erythromycylamine with the following physical-chemical constants: IR (CHCl 3 ) cm -1 : 3500, 2950, 2200, 1725, 1625, 1550, 1450, 1375, 1320, 1175, 1050, 750; 1 H NMR (300 MHz, CDCl 3 ) δ: 8.22 (1H, 9- NH -CH), 7.13 (1H,9-NH- CH =), 5.04 (1H, H-1"), 4.59 (1H, H-1'), 3.82 (1H, H-3), 3.68 (1H, H-5), 3.29 (3H, 3''-OCH 3 ), 3.23 (1H, H-2'), 2.31 [6H, 3'-N(CH 3 ) 2 ], 2.22 (1H, H-10), 1.94 (1H, H-8), 1.13 (3H, 8-CH 3 ), 1.05 (3H, 10-CH 3 ); 13 C NMR (75 MHz, CDCl 3 ) δ: 177.1 (C-1), 160.4 (9-NH- CH =), 132.2 (9-NH-CH=C), 116.1 (-CN), 114.6 (-CN), 101.6 (C-1') 95.4 (C-1"), 80.8 (C-5), 78.9 (C-3), 77.3 (C-4"), 70.5 (C-2'), 74.4 (C-9), 49.0 (3''-OCH 3 ), 40.0 [3'-N(CH 3 ) 2 ], 31.8 (C-10), 32.5 (C-8), 18.9 (8-CH 3 ), 13.6 (10-CH 3 ); FAB-MS m/z 811.5 (M+H) + EXAMPLE 4 9( S )- N -(β-Acetyl-β-carbethoxyethenyl)erythromycylamine According to the process described in Example 3 by the reaction of 9( S )-erythromycylamine (0.5 g; 0.68 mmol) and ethylα- (ethoxymethylene) acetoacetate (1.0 ml; 5.77 mmol) in toluene (20 ml) there were obtained 0.54 g of a resin residue. Chromatography over silica gel column using the solvent system CHCl 3 :MeOH = 9:1 gave 0.29 g of 9( S )- N -(β-acetyl-β-carbethoxyethenyl)erythromycylamine with the following physical-chemical constants: IR (CHCl 3 ) cm -1 : 3500, 2950, 1725, 1680, 1640, 1570, 1450, 1380, 1250, 1170, 1080; 1 H NMR (300 MHz, CDCl 3 ) δ: 11.15 (1H, 9- NH -CH=), 7.74 (1H,9-NH- CH =), 5.11 (1H, H-1"), 4.74 (1H, H-1'), 4.21 (1H, H-3), 3.71 (1H, H-5), 4.18 (3H, -COO CH 2 CH 3 ), 3.34 (3H, 3"-OCH 3 ), 3.24 (1H, H-5), 2.45 (3H, -CO CH 3 ), 3.23 (1H, H-2'), 2.34 [6H, 3'-N(CH 3 ) 2 ], 2.22 (1H, H-10), 1.94 (1H, H-8), 1.27 (3H, -COOCH 2 CH 3 ), 1.15 (3H, 8-CH 3 ), 1.04 (3H, 10-CH 3 ); 13 C NMR (75 MHz, CDCl 3 ) δ: 198.5 (- CO CH 3 ), 177.1 (C-1), 167.7 (- CO OCH 2 CH 3 ), 159.8 (9-NH- CH =), 132.2 (9-NH-CH= C ), 101.7 (C-1'), 95.3 (C-1"), 80.9 (C-5), 78.8 (C-3), 58.9 (-COO CH 2 CH 3 ), 77.4 (C-4"), 70.5 (C-2'), 75.1 (C-9), 48.8 (3"-OCH 3 ), 39.9 [3'-N(CH 3 ) 2 ], 32.1 (C-10), 33.2 (C-8), 30.4 (-CO CH 3 ), 18.1 (8-CH 3 ), 14.0 (-COOCH 2 CH 3 ), 12.9 (10-CH 3 ); FAB-MS m/z 875.2 (M+H) + .

Claims: 9-N-Ethenyl derivates of 9(S)erythromycylamine of the general formula (I) wherein R 1 represents a cyano group, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and wherein R 2 represents a cyano or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and pharmaceutically acceptable addition salts thereof with inorganic or organic acids. A compound according to claim 1, characterized in that R 1 represents a carboxylic group of the formula COOR 3 , and R 2 represents cyano group. A compound according to claim 2, characterized in that R 3 represents a C 1 -C 4 alkyl group. A compound according to claim 3, characterized in that the C 1 -C 4 alkyl group is an ethyl group A compound according to claim 1, characterized in that R 1 and R 2 are the same and represent a keto group of the formula COR 4 . A compound according to claim 5, characterized in that R 4 represents a C 1 -C 4 alkyl group. A compound according to claim 6, characterized in that the C 1 -C 4 alkyl group is a methyl group. A compound according to claim 1, characterized in that R 1 and R 2 are the same and represent a cyano group. A compound according to claim 1, characterized in that R 1 represents a carboxyl group of the formula COOR 3 and R 2 represents a keto group of the formula COR 4 . A compound according to claim 9, characterized in that R 3 represents a C 1 -C 4 alkyl group. A compound according to claim 10, characterized in that the C 1 -C 4 alkyl group is an ethyl group. A compound according to claim 9, characterized in that R 4 represents a C 1 -C 4 alkyl group. A compound according to claim 12, characterized in that the C 1 -C 4 alkyl group is a methyl group. A process for the preparation of 9-N-ethenyl derivatives of 9(S)-erythromycylamine of the general formula (I) wherein R 1 represents a cyano group, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and wherein R 2 represents a cyano or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and of pharmaceutically acceptable addition salts thereof with inorganic or organic acids characterized in that 9(S)-erythromycylamine of the general formula (II) is subjected to a reaction with ethoxyethylene derivatives of the general formula (III) wherein R 1 represents a cyano group, a carboxyl group of the formula COOR 3 , wherein R 3 represents a C 1 -C 4 alkyl group, or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, and wherein R 2 represents a cyano group or a keto group of the formula COR 4 , wherein R 4 represents a C 1 -C 4 alkyl group, in toluene, xylene or another aprotic solvent at a temperature from 20 ° to 80 °C and then, if appropriate, to a reaction with inorganic or organic acids. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and an antibacterially effective amount of compounds according to claim 1. The use of the compounds according to any of claims 1 to 13 for the preparation of pharmaceutical preparations for the treatment of bacterial infections.

Inventors: KELNERIC ZELJKO M SC, KOBREHEL GABRIJELA M SC, KUJUNDZIC NEDJELJKO D SC, LAZAREVSKI GORJANA M SC, PAVLOVIC DINA, KELNERIC, ZELJKO, M.SC., KOBREHEL, GABRIJELA, M.SC., KUJUNDZIC, NEDJELJKO, D.SC., LAZAREVSKI, GORJANA, M.SC., PAVLOVIC, DINA
Applicants: PLIVA PHARM & CHEM WORKS, PLIVA FARMACEUTSKA, KEMIJSKA, PREHRAMBENA I KOZMETICKA INDUSTRIJA, DIONICKO DRUSTVO
Application year: 1997
Main classification: C07H17
IPC codes: A61K31, C07H17, A61P31