Sulfonyl Derivatives of 2,5-Diphenylfurazan.

Abstract 2.5-Diphenylfurazan (2) was converted into the monosulfonyl chlorides (3a, 3b) on treatment with chlorosulfonic acid (~7 moles). These products were identified by reaction with secondary amines when both 3′- and 4′-sulfonyl derivatives were isolated. Under more forcing conditions, using a much larger excess of the reagent (~25 moles). bis-substitution was achieved. Although TLC indicated the formation of two products, after reaction with secondary amines only 3′3″-disulfonyl derivatives could be isolated. These results are discussed in electronic terms.