Steroidal N-nitroamines. Part 4. Intramolecular functionalization of N-nitroamine radicals: synthesis of 1,4-nitroimine compounds

Abstract

Photolysis of 6β-nitroamino-5α-cholestane (4), 6β-nitroamino-5α-cholestan-3β-yl-acetate (5), 2β-nitroamino-5α-cholestane (13), 4β-nitroamino-5α-cholestane (17), (20R)-20-nitroaminopregn-5-en-3β-yl acetate (26), (20R)-(31) and (20S)-(34)-nitroamino-5α-pregnan-3β-yl acetate, (23R, 25S)-3β-acetoxy-23-nitroamino-5β-spirostan (46), 3β-nitroaminofriedelane (53), and methyl 3β-nitroaminofriedelan-29-oate (54) in the presence of iodine and various oxidative reagents leads to neutral nitroaminyl radicals which undergo intramolecular hydrogen-abstraction to produce in most cases N-nitroimine compounds. Best results were obtained with the system iodine and (diacetoxyiodo) benzene.