Amosulalol

Description

Amosulalol is a potent antihypertensive with combined alpha and beta blocking properties. Indicated for the treatment of essential hypertension, it appears to possess a minimum of side-effects. Its beta-blocking property reduces the tachycardia associated with alpha-blockers, while its alpha-blocking activity reduces the peripheral vasoconstriction associated with beta-blockade.

Originator

Yamanouchi (Japan)

Manufacturing Process

A mixture of N-benzyl-2-(2-methoxyphenoxy)ethylamine, methyl ethyl ketone, and 5-bromoacetyl-2-methylbenzenesulfonamide was refluxed with stirring. After cooling the reaction mixture, ethyl ketone was distilled off under reduced pressure and the residue formed was dissolved in benzene. Then, ether was added to the solution and after removing the hydrobromide of N-benzyl-2-(2- methoxyphenoxy)ethylamine precipitated, the solvent was distilled off under reduced pressure to provide a viscous oily product.
The viscous oily product was dissolved in ethanol and after adding to the solution an excess amount of sodium borohydride, the mixture was stirred at room temperature followed by distilling off ethanol under reduced pressure. The residue was dissolved in ethyl acetate and the ethyl acetate layer recovered was washed with water, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to provide a viscous oily product. The product was subjected to a silica gel column chromatography and eluted using benzene and then a mixture of benzene and ethyl acetate of 10:1 by volume ratio to provide 5-{1-hydroxy-2-[N-benzyl-2-(2- methoxyphenoxy)ethylamino]ethyl}-2-methyl-benzenesulfonamide as a viscous oily product.
In 200 ml of methanol was dissolved 20.0 g of 5-{1-hydroxy-2-[N-benzyl-2- (2-methoxyphenoxy)ethylamino]ethyl}-2-methyl-benzenesulfonamide. After adding thereto 20 ml of ethanol containing about 10% hydrogen chloride and 1.0 g of 10% palladium charcoal, the mixture was shaken in hydrogen gas stream. When the absorption of hydrogen stopped, the catalyst was filtered away and the filtrate was distilled off under reduced pressure. The residue was dissolved in 100 ml of ethanol while it was hot and the solution was allowed to stand overnight in ice chamber, whereby 12.8 g of the α-type crystals of 5-{1-hydroxy-2-[2-(2-methoxyphenoxy)ethylamino]ethyl}-2- methylbenzenesulfonamide were obtained as the colorless crystals, melting point 169°-171°C.
In practice it is usually used as monohydrochloride

brand name

Lowgan

Therapeutic Function

Alpha-adrenergic blocker, Beta-adrenergic blocker, Antihypertensive