These compounds were prepared in 93% and 69% yields, respectively, by oxidation with m- chloroperbenzoic acid. For example, to 3.1 g (15 mmol) of N, N'-bis [dimethyl (methylthio)- methylldiazene'dissolved in 75 mL of CHC13 and cooled to 0" C was added dropwise 13 g (60 mmol) of 85% MCPBA in 100 mL of CHC13. The reaction mixture was stirred for 3 h at room temperature, washed with 5% bicarbonate (5 X 50 mL), dried