(+/-)-BUFURALOL HYDROCHLORIDE

Originator

Bururalol hydrochloride,Onbio Inc.

Definition

ChEBI: Bufuralol is a member of benzofurans.

Manufacturing Process

68.3 g (0.182 mol) of trimethyl-phenyl-ammonium perbromide were added in a single portion at 20°C to a stirred solution of 48.5 g (0.182 mol) of 5- bromo-2-acetyl-7-ethylbenzofuran in 400 ml of dry tetrahydro-furan. The resulting mixture was stirred at 20°C for 3 h, during which time trimethylphenyl- ammonium bromide precipitated out. The mixture was then poured into water and extracted 3 times with ether. The combined ether extracts were washed successively with water, saturated sodium bicarbonate solution, water and saturated brine, dried over anhydrous sodium sulfate, filtered and evaporated under reduced pressure. The solid residue was recrystallized from ethanol to yield 43.1 g of 5-bromo-2-bromoacetyl-7-ethylbenzofuran as yellow crystals, melting point 101-102°C.
1.35 g of sodium borohydride were added portion-wise at room temperature over a period of 20 min to a stirred solution of 17.3 g (0.05 mol) of 5-bromo- 2-bromoacetyl-7-ethylbenzofuran in 100 ml of dioxane and 25 ml of water.
The mixture was stirred at room temperature for 3 h, then dioxane was removed by evaporation at 40°C under reduced pressure and the residue was diluted with water and extracted 3 times with ether. The combined ether extracts were worked up in the usual manner to yield 16.0 g of crude 5- bromo-2-(2-bromo-1-hydroxyethyl)-7-ethyl-benzofuran as a viscous oil. 16.0 g of crude 5-bromo-2-(2-bromo-1-hydroxyethyl)-7-ethylbenzofuran and 37.0 g of t-butylamine were heated at 100°C in a sealed autoclave for 24 h. After cooling, excess t-butylamine was evaporated off and the residue was taken up in dilute aqueous hydrochloric acid. The aqueous solution was washed twice with ether, basified with dilute aqueous sodium hydroxide solution and extracted twice with ether. The combined ether extracts were washed with water and with brine, dried over anhydrous sodium sulfate, filtered and evaporated. The solid residue was crystallized from petroleum ether (boiling point 60-80°C) to yield 4.7 g of 5-bromo-2-(2-t-butylamino-1- hydroxyethyl)-7-ethylbenzofuran as buff crystals, melting point 101-103°C.
4.8 g of 5-bromo-2-(2-t-butylamino-1-hydroxyethyl)-7-ethylbenzofuran in 50 ml of ethanol were hydrogenated at room temperature and atmospheric pressure in the presence of 0.3 g of 5% palladium-on-carbon catalyst. After the uptake of one equivalent of hydrogen, the hydrogenation was terminated, catalyst was filtered off and the filtrate was evaporated to dryness. The residue was basified and extracted twice with ether. The combined ether extracts were worked up in the usual manner to give 2-(2-t-butylamino-1- hydroxyethyl)-7-ethylbenzofuran in the form of an oil. In practice it is usually used as hydrochloride.

Therapeutic Function

Beta-adrenergic blocker