Patent ID: 6916803

Claim:
A compound selected from the group consisting of a Syn isomer of a racemate and an optical isomer of 3-(heteroaryl acetamido)-2-oxo-axetidine-1-sulfonic acid and of formula I Wherein M is a hydrogen or pharmaceutically acceptable salt forming cation; X is CH, N or C-halogen; R is C 1 -C 3 alkyl which is unsubstituted or substituted with at least one of (a) a halogen atom (b) OR 5 wherein R 5 is hydrogen, CONH 2 provided that, when R is methyl, it cannot be substituted with both a halogen atom and OR 5 ; R 1 and R 2 independently are OH, COOH, CONH 2 , NH 2 , dimethylamino, OCH 3 , NO 2 , CN, optionally substituted phenyl or C 1 -C 3 alkyl; or R 1 and R 2 together are —O—CH═CH—CH 2 —, —O—CH 2 —CH 2 —O—, —CH 2 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —CH 2 —, —CH═CH—CH═CH— or —CH═C(OH)—C(OH)═CH— which together with the carbon atoms to which they are bound form a 5 membered or six membered cyclic ring; and R 3 and R 4 independently are hydrogen, optionally substituted C 1 -C 3 alkyl, optionally substituted phenyl or C 3 -C 6 cycloalkyl; or R 3 and R 4 together with the C to which they are attached are C 3 -C 6 cycloalkyl.