| abstract |
There are disclosed 5-substituted-3-isoxazolecarboxylic acid derivatives having the general formula:n wherein X is a phenyl group, a thienyl group a furyl group or a pyridyl group, each of which groups optionally contains at least one substituent group, R is a phenyl group or a hydroxyphenyl group, and A is the following group:n wherein Y is;n (the carbon atom of Y to which the carboxyl group is attached, being attached to the nitrogen atom of A) wherein M is a hydrogen atom or a substituent group, and Z is a hydrogen atom, a hydroxy group, an acyloxy group, a carbamoyloxy group, an aromatic heterocyclethio group or an aromatic nitrogen-containing heterocycle quartemary ammonium group. The derivatives are useful as antibiotics. |