Synthesis of 1,1-dioxopenicillanoyloxymethyl 6-[d-α-(benzylideneaminophenylacetamido)]penicillanate and analogs. New intermediates in the preparation of sultamicillin

The synthesis of benzylidene imines of sultamicillin and analogs 1 is described. These new compounds showed high stability and were prepared under very mild conditions and high yields. Furthermore, they are convenient starting materials for the preparation of sultamicillin 5 (important prodrug of ampicillin and sulbactam) as its base form, by deprotection of the amino group with Girard reagents.