The reactions of thebaine with C-nitroso-compounds

The reactions of thebaine with nitrosoarenes to form Diels–Alder adducts have been investigated. Reversibility of the addition of a series of parasubstituted nitrosoarenes to thebaine has been qualitatively studied by NMR spectrometry. The direction of the addition was found to be highly stereospecific giving adducts that were readily hydrolysed to previously inaccessible 14-aminocodeinone derivatives. No adducts of nitrosoalkanes with thebaine could be prepared but the parent codeinone corresponding to a formal addition of monomeric hyponitrous acid to thebaine was readily formed by reaction of the latter with 1-chloro-1-nitrosocyclohexane in acid solution. Nitrosyl cyanide, formed from reaction of nitrosyl chloride with silver cyanide, was found to react with thebaine to give a normal adduct. With the dienophile in excess an N-cyanomethylnorthebaine-nitrosyl cyanide adduct was obtained. Evidence for the existence and structure of nitrosyl cyanide was investigated further by undertaking a study of its reactions with other conjugated dienes to give N-cyano-1,2-oxazines. The visible spectrum of the green gaseous products from reaction of nitrosyl chloride with silver cyanide showed an n → π* transition with a maximum absorption at 738 nm. This is a typical absorption maximum for a blue monomeric nitrosoalkane.