amidephrine mesylate

Originator

Amidefrine,Pharm. Chemical

Uses

Adrenergic.

Manufacturing Process

A solution of N-benzylmethylamine 7.27 g (0.06 mole) in 25 ml of acetonitrile is added dropwise during 10 min to a solution of 8.76 g (0.03 mole) of 3-(2- bromoacetyl)methanesulfonanilide (M.P. 118-121°C) in 100 ml of acetonitrile. External cooling is employed to maintain a reaction temperature of 10°C during the addition. The cooling bath is then removed and the solution stirred for an additional 20 min. Concentration of the reaction mixture yields a yellow oil which is dissolved in 300 ml of ether and washed with water to remove byproduct N-benzylmethylamine hydrobromide. The ethereal solution is dried over magnesium sulfate and the solvent distilled leaving a viscous oil. The oil is purified by dissolving in ether (250 ml), and filtering the ether solution through diatomaceous earth to remove insoluble colored impurities. The treated ether solution is diluted with 100 ml of acetonitrile. Treatment of the ether-acetonitrile solution with an ether solution of methanesulfonic acid yields 3-(2-benzylmethylaminoacetyl)methanesulfonanilide methanesulfonate as a white precipitate which is collected and washed with 100 ml of 1:1 acetonitrile-ether and dried. It weighs 9.0 g (70%), and exhibits M.P. 197.5- 201°C. It is recrystallized from 96% ethanol, yielding 8.0 g (62.3%) of the 3- (2-benzylmethylaminoacetyl)methanesulfonanilide methanesulfonate as a crystalline product, M.P. 206-209°C.
A solution of 31.8 g (0.74 mole) of 3-(2-benzylmethylaminoacetyl) methanesulfonanilide methanesulfonate in 700 ml of absolute ethanol is reduced in an atmospheric hydrogenation unit (2 to 5 p.s.i. g positive pressure) during 24 hours with a 10% palladium catalyst prepared from 320 mg of palladium chloride and 2.0 g of pulverized charcoal. After absorption of the calculated amount of hydrogen, the catalyst is filtered, the filtrate concentrated to about 100 ml, mixed with about 500 ml of ether, resulting in precipitation of a white solid weighing 24.3 g (96%), M.P. 201-203.5°C. Two recrystallizations from ethanol (35 ml/g of solid) yield the analytically pure 3- (2-methylamino-1-hydroxyethyl)methanesulfonanilide methanesulfonate, 19.6 g (75%), M.P. 207-209°C.
3-(2-Methylamino-1-hydroxyethyl)methanesulfonanilide methanesulfonate, 17.0 g (0.05 mole) is dissolved in 50 ml of 1 N sodium hydroxide, yielding a yellow solution having pH 8. The water is removed from the solution by evaporation in vacuo and the residue is treated with several portions of ethanol which are evaporated to remove last traces of moisture. The bulk of the sodium methanesulfonate byproduct is then removed from the residue by dissolving the product in 350 ml of hot absolute ethanol and clarifying by filtration through a diatomaceous earth filter aid. The ethanolic filtrate is evaporated to dryness. Last traces of sodium methanesulfonate are then removed by washing the residue with 15 ml of cold water and then with two 15 ml portions of 1:1 cold water-isopropanol, and finally with ether, yielding 7.7 g of 3-(2-methylamino-1-hydroxyethyl)methanesulfonanilide as a white solid, M.P. 159-161°C.
In practice it is usually used as monomethanesulfonate salt.

Therapeutic Function

Vasoconstrictorá Nasal decongestant

Raw materials

Preparation Products