| abstract |
Compounds of the formula (I)n n in which R₁ represents a hydrogen atom or a hydroxyl protecting group; nR₂ represents a hydrogen atom, a carboxyl protecting group or a cation derived from an inorganic base or an organic base; nR₃ represents the group O(CH₂) n R₄ in which n is an integer from 2 to 6 and R₄ represents a halogen atom or a hydroxy, C₁₋₃alkoxy, C₁₋₃ alkythio, azido, cyano, nitro or quaternary ammonium group N⁺R₅R₆R₇X⁻wherein R₅ and R₆ independently represent a C₁₋₃alkyl group, R₇ is a C₁₋₂ alkyl group and X⁻ is a pharmaceutically acceptable anion and metabolically labile esters, salts and solvates thereof, and processes for their production. |