Acebutolol hydrochloride

Manufacturing Process

Crude 5'-butyramido-2'-(2,3-epoxypropoxy)acetophenone (16 g), isopropylamine (20 g) and ethanol (100 ml) were heated together under reflux for 4 hours. The reaction mixture was concentrated under reduced pressure and the residual oil was dissolved in N hydrochloric acid. The acid solution was extracted with ethyl acetate, the ethyl acetate layers being discarded. The acidic solution was brought to pH 11 with 2 N aqueous sodium hydroxide solution and then extracted with chloroform. The dried chloroform extracts were concentrated under reduced pressure to give an oil which was crystallized from a mixture of ethanol and diethyl ether to give 5'-butyramido- 2'-(2-hydroxy-3-isopropylaminopropoxy)acetophenone (3 g), MP 119-123°C. Crude 5'-butyramido-2'-(2,3-epoxypropoxy)acetophenone used as starting material was prepared as follows: p-butyramidophenol (58 g; prepared according to Fierz-David and Kuster, Helv. Chim. Acta 1939,2282), acetyl chloride (25.4 g) and benzene (500 ml) were heated together under reflux until a solution formed (12 hours). This solution was cooled and treated with water. The benzene layer was separated and the aqueous layer was again extracted with benzene. The combined benzene extracts were dried and evaporated to dryness under reduced pressure to give p-butyramidophenyl acetate (38 g) as an off-white solid, MP 102-103°C. A mixture of p-butyramidophenyl acetate (38 g), aluminum chloride (80 g) and 1,1,2,2-tetrachloroethane (250 ml) was heated at 140°C for 3 hours. The reaction mixture was cooled and treated with iced water. The tetrachloroethane layer was separated and the aqueous layer was extracted with chloroform. The combined organic layers were extracted with 2 N aqueous sodium hydroxide and the alkaline solution was acidified to pH 5 with concentrated hydrochloric acid. The acidified solution was extracted with chloroform and the chloroform extract was dried and concentrated under reduced pressure to give 5'-butyramido-2'-hydroxyacetophenone (15.6 g), MP 114-117°C. A solution of 5'-butyramido-2'-hydroxyacetophenone (15.6 g) in ethanol (100 ml) was added to an ethanolic solution of sodium ethoxide which was prepared from sodium (1.62 g) and ethanol (100 ml). The resulting solution was evaporated to dryness under reduced pressure and dimethylformamide (100 ml) was added to the solid residue. Approximately 10 ml of dimethylformamide was removed by distillation under reduced pressure. Epichlorohydrin (25 ml) was added and the solution was heated at 100°C for 4 hours. The solution was concentrated under reduced pressure to give a residual oil which was treated with water to give a solid. The solid was dissolved in ethanol and the resulting solution was treated with charcoal, filtered and concentrated under reduced pressure to give crude 5'-butyramido- 2'-(2,3-epoxypropoxy)acetophenone (16 g), MP 110-116°C. The crude compound may be purified by recrystallization from ethyl acetate, after treatment with decolorizing charcoal, to give pure 5'-butyramido-2'-(2,3- epoxypropoxy)acetophenone, MP 136-138°C.

Therapeutic Function

beta-Adrenergic blocker

Safety Profile

Poison by ingestion, subcutaneous,intravenous, and intraperitoneal routes. An experimentalteratogen. Other experimental reproductive effects. Whenheated to decomposition it emits toxic fumes of NOx andHCl.

Definition

ChEBI: The hydrochloride salt of acebutolol, prepared using equimolar amounts of acebutolol and hydrogen chloride.

Brand name

Sectral (Dr. Reddy’s).