Methylamine → HCID 22901843, compound

Participants

Reaction Steps

68.5 ml of aqueous methylamine solution (40%) are added dropwise to a solution of 78 g of 3-acetylmethyl-2,3-dihydro-5-methyl-2-oxo-1,3,4-oxadiazole in 500 ml of acetonitrile. After the slightly endothermal reaction has subsided, the orange mixture is stirred-for 30 minutes at 48° and then evaporated. The residue is treated with 100 ml of tetrahydrofuran and 200 ml of ethyl acetate, during which process crystals precipitate. The crystals are filtered off, washed with ethyl acetate and dried under reduced pressure at 60°. This gives a mixture of 1-acetylamino-2,3-dihydro-3,4-dimethyl-2-oxo-1H-imidazole and 1-acetylamino-3,4-dimethyl-4-methylamino-2-oxo-imidazolidine. A sample of this mixture is separated on silica gel using ethyl acetate/methanol (2:1) as eluent, yielding the pure 1-acetylamino-2,3-dihydro-3,4-dimethyl-2-oxo-1H-imidazole which melts at 199°-201° and the pure 1-acetylamino-3,4-dimethyl-4-methylamino-2-oxo-imidazolidine which melts with decomposition at 150°-152°. Another sample of the above-mentioned mixture is heated to 175° and held at this temperature until the evolution of methylamine gas has ceased. The residue is cooled and stirred with a small amount of methanol. Filtration of the suspension gives the pure title compound melting after drying at 199°-201°.

Provenance & Evidence