sodium 2,2,2-trichloroethyl hydrogen phosphate

Chemical properties

A white or almost white powder; hygroscopic.

Originator

Triclos,Merrell National,US,1972

The Uses of sodium 2,2,2-trichloroethyl hydrogen phosphate

Sedative-hypnotic.

Manufacturing Process

Trichloroethanol (500 grams) and phosphorus oxychloride (510 grams) were added to dry diethyl ether (3.5 liters) and stirred at 10°C with ice/water cooling. Dry pyridine (270 ml) was added dropwise over 1 hour, maintaining the temperature below 25°C. The resulting suspension was stirred for a further 1 hour and then stood at 0°C overnight. The pyridine hydrochloride was removed by filtration and washed with diethyl ether (2 x 300 ml) and dried in vacuo over P2O5 to give 380 grams.
The ether filtrate and washings were evaporated at room temperature under reduced pressure to give a clear liquid residue (801 grams). This residue was distilled under high vacuum to give trichloroethyl phosphorodichloridate (556 grams, 62.4% of theory), boiling point 75°C/0.8 mm.
The phosphorodichloridate was hydrolyzed by adding to a stirred solution of sodium carbonate (253 grams) in water (2.9 liters). After 1 hour the solution was cooled and acidified with a solution of concentrated sulfuric acid (30 ml) in water (150 ml) and then extracted with a mixture of tetrahydrofuran and chloroform (2.3/1; 3 x 1 liter). The tetrahydrofuran/chloroform liquors were bulked and evaporated to dryness to give a light brown oil. This was dissolved in water (1 liter) and titrated with 2 N sodium hydroxide solution to a pH of 4.05 (volume required 930 ml). The aqueous solution was clarified by filtration through kieselguhr and then evaporated under reduced pressure to a syrup (737 grams).
Hot acetone (4.5 liters) was added to this syrup and the clear solution stood at room temperature for 2 hours and then at 0°C overnight. The white crystalline solid was filtered off, washed with acetone (2 x 400 ml) and dried at 60°C in vacuo to give sodium trichloroethyl hydrogen phosphate (414 grams, 49.3% of theory from trichloroethanol).

brand name

Triclos (Sanofi Aventis).

Therapeutic Function

Sedative, Hypnotic