New Angular Phenoxazine and Triangular Benzoxazinophenothiazine Dyestuffs

Abstract

In this study, the synthesis of new angular phenoxazine and triangular benzoxazinophenothiazine dyestuffs is described. This was achieved by the synthesis of 10-amino-6-chlorobenzo[a]phenoxazin-5-one intermediate. The intermediate was converted into 10-amino-6-phenylbenzo[a]phenoxazin-5-one by Suzuki-Miyaura cross-coupling with phenyl boronic acid. Acetylation as well as diazotization of the intermediate supplied N-(oxo-6-phenyl-5H-benzo[a]phenoxazin-10-yl) acetamide and N-(oxo-6-phenyl-5H-benzo[a]phenoxazin-10-yl)-azo-b-naphthol in high yields as new dyes respectively. In another development, the intermediate 10-amino-6-chlorobenzo[a]phenoxazin-5-one was reacted with another mole of 2,3-dichloro-1,4-naphthoquinone to afford 12-aminobenzo[a][1,4]benzoxazino[3,2-c]phenothiazine which was acetylated to obtain N-(benzo[a]benzo[5,6][1,4]oxazino[3,2-c]phenothiazin-12-yl)acetamide. The reaction of 2-naphthol with diazotized 12-aminobenzo[a][1,4]benzoxazino[3,2-c]phenothiazine gave N-(benzo[a]benzo[5,6][1,4]oxazino[3,2-c]phenothiazin-12-yl)-azo-b-naphthol as new dye. Structural assignments were confirmed by spectral and elemental analytical data.