Methyl iodide → 3,4-dihydro-5-methyl-2-[(1,5-dimethylimidazol-4-yl)methyl]pyrimido[1,6-a]indol-1(2H)-one

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Reaction Steps

To a solution of 3,4-dihydro-5-methyl-2-[(5-methyl-1H-imidazol-4-yl)methyl]pyrimido[1,6-a]indol-1(2H)-one (343 mg) in N,N-dimethylformamide (20 ml) was added sodium hydride (60% in mineral oil, 51.3 mg) at 5° C. and the mixture was stirred at the same temperature for 30 minutes. Methyl iodide (182 mg) in N,N-dimethylformamide (10 ml) was added dropwise to the solution at 50° C. during 2 hours. After 30 minutes of stirring at the same temperature, the reaction mixture was evaporated in vacuo. The residue was diluted with a mixture of tetrahydrofuran and ethyl acetate (1:3, 20 ml), washed with brine, dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by silica gel column chromatography (3% -methanol-chloroform) to give 3,4-dihydro-5-methyl-2-[(1,5-dimethylimidazol-4-yl)methyl]pyrimido[1,6-a]indol-1(2H)-one as crystal. The crystal was dissolved with 2N-hydrochloric acid (2 ml) and evaporated in vacuo. The crystalline residue was washed with acetone to give 3,4-dihydro-5-methyl-2-[(1,5-dimethylimidazol-4-yl)methyl]pyrimido[1,6-a]indol-1-(2H)one hydrochloride (0.2 g).

Provenance & Evidence