Preparation and dienophilic reactions of nitrosyl cyanide

Abstract

Nitrosyl chloride and silver cyanide react at low temperatures to give nitrosyl cyanide (ONCN) which undergoes 1,4-cycloaddition reactions with conjugated dienes to form the corresponding 2-cyano-3,6-dihydro-2H-1,2-oxazines. Thus, the alkaloid, thebaine (1), reacted with a limited quantity of nitrosyl cyanide to form a single adduct (2; R = H, X = CN) convertible into 14-cyanamidocodeinone (3); with an excess of nitrosyl cyanide the related N-cyanomethyl derivative (2; R = X = CN) was formed. Similarly, N-cyano-oxazines have been prepared from buta-1,3-diene and its 2,3-dimethyl, 1-methoxycarbonyl-4-methyl, 1-cyano-4-methyl, and 1,4-bisethoxycarbonyl derivatives. Base-induced rearrangements reactions leading to a pyridone (7), a pyrrolinone (11), and a mixture of dihydrofurans (14) are described.