A mixture of 21.8 g. (0.112 mol.) of 3-chloro-1,2-diacetoxypropane, 28.0 g. (0.083 mol.) of 10-trifluoromethyl-1H-pyrimido[5,4,3-kl]phenothiazine-1,3(2H)-dione and 3.36 g. (0.080 mol.) of sodium hydride in 200 ml. of dry dimethylformamide was heated at 100°-110° for 40 hours in the presence of a catalytic amount of potassium iodide. The reaction mixture was filtered and the filtrate was evaporated to dryness under reduced pressure to give 2-(2,3-diacetoxypropyl)-10-trifluoromethyl-1H-pyrimido[5,4,3-kl]phenothiazine-1,3(2H)-dione.
