Hydrogen Sulfide → 10H-phenothiazine-2-carbothioamide

Participants

Reaction Conditions

Reaction Steps

A solution of 10-[(2RS)-1-diethylamino-2-propyl]2-phenothiazinecarbonitrile (5.66 g) and triethylamine (2.35 cc) in pyridine (113 cc) is treated with hydrogen sulphide for 1 hour and then stirred for 3 days at a temperature in the region of 20° C. The greenish solution obtained is purged with nitrogen, poured into distilled water (500 cc) and extracted with ethyl acetate (2×500 cc). The combined organic phases are washed successively with distilled water (2×200 cc) and with saturated aqueous sodium chloride solution (200 cc), dried over magnesium sulphate, filtered and concentrated to dryness under reduced pressure (30 mm Hg, 4 kPa) at 40° C. The residual orange oil (9.1 g) is purified by chromatography on a column (height: 25 cm, diameter: 3 cm) of silica gel (0.04-0.063 mm) with a slight excess pressure of nitrogen (40 kPa), eluting with ethyl acetate (750 cc) and collecting 50-cc fractions. The combined fractions 4 to 10 are concentrated to dryness under reduced pressure (30 mm Hg; 4 kPa) at 40° C. 10-[2RS)-1-diethylamino-2-propyl]-2-phenothiazinecarbothioamide (6.2 g) is thereby obtained in the form of an orange oil.

Provenance & Evidence