| abstract |
There is described the stereoselective total synthesis by a variety of routes of novel suitably substituted DELTA 2,3-1, 4-morpholine-2-carboxylic acids possessing a fused beta -lactam ring in the 1,6-position and carrying a substituent cis to carbon 5 in the 7-position of the fused ring system represented by the general formula <IMAGE> wherein Q is hydrogen, alkyl, aralkyl or -CH2COOZ where Z is hydrogen or the residue of an ester group and X is amino, azido or acylamino. Also included in the invention are compounds of the above formula in which the carboxyl group at the 2-position is protected as by an easily cleavable ester group and salts of both the free acids and carboxyl-protected compounds. Those compounds in which X is acylamino and their physiologically hydrolyzed esters and pharmaceutically acceptable salts are potent antibacterial agents. |