Compounds and their use

A method of treating a carbapenemase-producing bacterial infection in a subject in need thereof comprising administering to the subject a therapeutically effective amount of one or more antibiotics and a compound of formula (I)

• or tautomeric forms, stereoisomers, polymorphs, solvates, hydrates, pharmaceutically acceptable salts and esters thereof, thereby treating the carbapenemase-producing bacterial infection,
• wherein:
• A=C or N;
• Het is a substituted three- to seven-membered heterocyclic ring;
• R1 represents a carboxylate anion or —COOR4, wherein R4 represents hydrogen, C1-C6alkyl, C6-C10aryl, C6-C10arylC1-C6alkyl, methoxybenzyl, nitrobenzyl, silyl, diphenylmethyl, or a pharmaceutically acceptable salt;
• R2 and R3 may be same or different and independently represent hydrogen, halogen, amino, protected amino or optionally substituted C1-C6alkyl, C2-C6 alkenyl or C2-C6 alkynyl;
• R represents a substituted or unsubstituted C1-C6 alkyl, C2-C6alkenyl, C6-C10aryl, C6-C10arylC1-C6alkyl, C3-C12cycloalkyl, oxo, heterocyclyl or heterocyclylalkyl group;
• and
• when the groups R, R2 and R3 are substituted, the substituents which may be one or more are selected from lower alkyl;
• lower alkoxy;
• lower alkylthio;
• lower alkylamino;
• cyclo(lower)alkyl;
• cyclo(lower)alkenyl;
• hydroxy;
• halogen;
• amino;
• protected amino;
• cyano;
• nitro;
• carbamoyl;
• —CONHC1-C4alkyl-COO—C1-C4alkyl;
• carboxy;
• protected carboxy;
• —COO—C1-C4alkyl;
• —CO-heterocyclyl;
• sulfonyl;
• sulfamoyl;
• imino;
• oxo;
• amino(lower)alkyl;
• halo(lower)alkyl;
• and carboxylic acid and carboxylic acid derivatives, wherein the carbapenemase produced by the carbapenemase-producing bacteria is KPC.