| abstract |
Compounds of formula (I) in which R1 represents a hydrogen atom or a hydroxyl protecting group; R2 represents a hydrogen atom, a carboxyl protecting group or a cation derived from an inorganic base or from an organic base; R3 represents the group O (CH2) nR4 in which n is an integer ranging from 2 to 6 and R4 represents a halogen atom or a hydroxy, a C1-3 alkoxy, a C1-3 alkythio, an azido, a cyano, a nitro or a quaternary ammonium group N + R5R6R7X- in which R5 and R6 independently represent a C1-3 alkyl group, R7 represents a C1-2 alkyl group and X- is a pharmaceutically acceptable anion. Metabolically labile esters, their salts and solvates, and methods of making same, are also described. |