The reaction of N-alkylhydroxamic acids with sulphinyl chlorides

Abstract

The reaction of several N-methylhydroxamic acids with methane- and benzene-sulphinyl chloride is shown to give an isolatable O-sulphinylated intermediate (IV) below 0 °C. The intermediates decompose at ambient temperatures with simultaneous N–O and S–O bond fission to give the isomeric N-acyl-N-methylsulphonamide (V) and N-methyl-O-sulphonylhydroxamic acid (VI) by in-cage and free pair radical recombination. ¹H and ¹³C n.m.r. spectra show strong polarisations in both sulphonamide (V) and O-sulphonylhydroxamic acid (VI), indicating radical cage mechanisms. In addition, a strong e.s.r. signal was observed due to the N-acyl-N-methylnitroxyl radical (X).