Transformations of penicillins: reactions with chloramine T

Abstract

Reaction of chloramine T trihydrate with certain 6β-amidopenicillanates affords β-lactam-fused thiadiazine S-imides. The structure of one S-imide was established by X-ray crystallography and those of the others were deduced by spectroscopic comparison. Penicillanates lacking a secondary amide group at C-6 did not undergo comparable reaction. The β-lactam-fused heterocyclic S-imides were particularly stable towards a series of reactants, including oxidising and reducing reagents. Trichloroethyl 6β-phenylacetamidopenicillanate was significantly different in its reactivity towards chloramine T, affording β-lactam-fused oxazolines and a monocylic chlorozetidinone. A by-product in these reactions was identified as NN′-thiobis(toluene-p-sulphonamide).