Rmi 82249 → 1,3-diacetyl-1,3-dihydro-4-(4-methoxybenzoyl)-5-methyl-2H-imidazol-2-one

Participants

Reaction Steps

A mixture of 46.4 g of 1,3-dihydro-4-(4-methoxybenzoyl)-5-methyl-2H-imidazol-2-one and 200 ml of acetic anhydride is refluxed for 2 hours. The mixture is distilled to remove 100 ml of acetic anhydride and acetic acid; this is replaced by fresh acetic anhydride and refluxing is resumed. After a total of 4 hours of reflux, excess acetic anhydride is evaporated under reduced pressure and the resulting residue is crystallized from ethanol to give 1,3-diacetyl-1,3-dihydro-4-(4-methoxybenzoyl)-5-methyl-2H-imidazol-2-one melting at about 123°-125° C.

Provenance & Evidence