abstract |
Pharmaceutical compounds of the formula <IMAGE>1-4 alkyl-carbonyl, and R2 is carboxy, tetrazolyl, C1-4 alkyl-sulphonamido or -CR4R5CO2H where R4 and R5 are each hydrogen or C1-4 alkyl; provided that when R1 and R3 are both methyl and when R1 and R3 are both methylcarbonyl, R2 is not carboxy; and salts and esters thereof. |