Transformations of penicillins: New methods of formation and reactions of 6,6-disubstituted penams and 7,7-disubstituted cephems

The reactions of penicillanate esters with ethyl or trichloroethyl N-chloro-N-sodiocarbamate gave 6a-ethoxyformamido and 6a- trichloroethoxyformamido-6ß-acylaminopenicillanates, respectively. The 6a-trichloroethoxyformamido-group was transformed in certain penicillanates into a 6a-amino-group. 7ß-Acylamino-7a- ethoxyformamidodeacetoxycephalosporanates were formed from the appropriate 6,6-disubstituted penicillanate S-oxides. The reaction of the 6,6-disubstituted penicillanates with phosgene led to a 1-ethoxycarbonyl-2-oxo-3-phenoxyacetyl-1, 3-diazetidine-4-spiro-6'-penicillanate.