Rearrangement of nitrones to amides using chlor0sulfonyl isocyanate

Abstract

Reaction of chlorosulfonyl isocyanate (CSI) with nitrones 1 a-n and 5 a,b has been studied. α, α, N-Triaryl nitrones 1 a-n react with CSI to form the N,N-diaryl arylamides 3 a-n and 4 i-n in good yields. In the case of α-H, α, N-diaryl nitrones 5 a,b however, two compounds viz., the rearranged product 11 a,b and the 1,4-dihydro tetrazines 10 a,b are formed. The effect of substituents on the rearrangement has been studied. It is found that the nature of the substituent has got a profound effect on the rearrangement. We have also noted that the rearrangement is independent of the syn or anti configurations of the nitrones.