2,2-dimethyl-8-oxo-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3t,7t-dicarboxylic acid 3-benzyl ester 7-tert-butyl ester
2,2-dimethyl-8-oxo-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3c,7t-dicarboxylic acid 3-benzyl ester 7-tert-butyl ester
2,2-dimethyl-8-oxo-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3c,7t-dicarboxylic acid 3-benzyl ester
2-bromo-3-methyl-but-2-enoic acid benzyl ester
α,β-dibromo-β,β-dimethylpropionic acid
2,2-dimethyl-8-oxo-7c-(2-phenyl-acetylamino)-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3t-carboxylic acid
2,2-dimethyl-8-oxo-7t-(2-phenyl-acetylamino)-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3t-carboxylic acid
2,2-dimethyl-8-oxo-7t-(2-phenyl-acetylamino)-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3t-carboxylic acid benzyl ester
2,2-dimethyl-8-oxo-7c-(2-phenyl-acetylamino)-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3t-carboxylic acid benzyl ester
2,2-dimethyl-8-oxo-7c-(2-phenyl-acetylamino)-(6rH)-4-thia-1-aza-bicyclo[4.2.0]octane-3c-carboxylic acid benzyl ester