4-(Dimethylamino)Benzaldehyde → Imidazolium Acetate

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Reaction Steps

9 g of 1-amino-2-(p-methoxyphenyl)imidazole are dissolved in 300 ml of glacial acetic acid, whereupon the solution is treated with 21.3 g of p-(dimethylamino) benzaldehyde. After 24 hours, the mixture is evaporated and the residue is placed on a column loaded with 300 g of silica gel. The product is eluted with dichloro-methane/methanol (95:5). The dark eluate is treated with active carbon and evaporated. The product is crystallized twice from methylene chloride/petroleum ether. There is obtained 1-[[p-(dimethylamino)benzylidene]amino]-2-p-methoxyphenyl)imidazolium acetate of melting point 93°. The resulting salt is treated with aqueous sodium bicarbonate solution and extracted with dichloromethane. The extract is dried over sodium sulfate and evaporated. The product is crystallized from petroleum ether. There is obtained 1-[[p-(dimethylamino)benzylidene]amino]-2-(p-methoxyphenyl)imidazole of melting point 108°.

Provenance & Evidence