Direct Nitration Reactions of Photochromic Spirooxazines

ABSTRACT A direct nitration of photochromic spirooxazines was carried out by three different methods. The molecular structure of main products was determined by NMR 1H and 13C spectra. The nitration mechanisms were proposed. It was shown that only nitration by mixture of nitric and sulfuric acids gives photochromic compounds with nitrogroup in aryloxazine ring.