2,10-Dinitro-3H,12H-[1,4]benzothiazino[3,2-b]phenothiazin-3-one

2,4-Dinitrophenolor its Sodium salt (by 1-Chloro-2,4-dinitrobenzene alkaline hydrolysis) and Sodium polysulfide heating, in 110 ~ 120 ℃ reflux heating 48 to 72 hours, or in 130 ~ 140 ℃ under pressure to short time heating, then dilution melt, adding acid or air oxidation make dye completely precipitated out. In the molten material to the intermediate Sodium polysulfide proportion must be appropriate, such ability in reaction end solution almost no dye residual. According to dye the preparation process of the use conditions, has determined the empirical formula is C24H16N6O8S7 orC24H16N6O8S8