Hydrochloric Acid → 2,3,4,4a-Tetrahydro-6-methyl-1H-pyrazino[1,2-a]quinoxalin-5(6H)-one

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Reaction Steps

To a stirred suspension of 0.87 g. (0.0180 mole) of sodium hydride (50% suspension in nujol) in 50 ml. of dimethyl formamide under a nitrogen atmosphere is added 5.5 g. (0.968 mole) of 3-carbobenzoxy-2,3,4,4a-tetrahydro-1H-pyrazino[1,2-a]quinoxaline-5(6H)-one. The mixture is stirred 1/2 hours, then to it is added 4.5 g. of methyl iodide in 10 ml. of dimethylformamide. The resultant mixture is stirred for 1 hour, then poured into 100 ml. of water. The aqueous mixture is extracted with methylene chloride, dried (MgSO4) and concentrated to give 5.7 g. of viscous glass. This glass is dissolved in 150 ml. of ethanol containing 0.3 g. of hydrogen chloride and hydrogenated over 5 g. of 10% palladium on carbon for 51/2 hours at 45 p. s. i. hydrogen pressure with the temperature about 50°. The catalyst is filtered and the filtrate is concentrated. Recrystallization of the residue from ethanol gives 1.9 g. of product as the hydrochloride salt, m.p. 260°-264°.

Provenance & Evidence