Reaction of NH-azoles with O-fluorosulfonyl-N,N-difluorohydroxylamine. Synthesis of N-fluorosulfonylazoles
摘要:
O-Fluorosulfonyl-N,N-difluorohydroxylamine (FH) reacts with anions of NH-azoles (imidazoles, pyrazoles, and 1,2,3-triazoles) to give the corresponding N-fluorosulfonylazoles, which were used to obtain N,N'-sulfonylbisazoles. The N-fluorosulfonylation proceeds at the nitrogen atom furthest from the most electron-withdrawing substituent in the azole ring. Nonaromatic NH-acid anions (imides and primary N-nitroamines) are sometimes capable of giving N-fluorosulfonyl derivatives although in yields less than 5 %. These products are much less stable than N-fluorosulfonylazoles. The N-fluorosulfonylation presumably proceeds as nucleophilic substitution at the sulfur atom of FH.