Benzyl-4,5-dimethylimidazole 3-oxide

At-Methylenebenzylamine (11.9g, 0.09 mol) is added dropwise to a solution of biacetyl monoxime (10.1 g, 0.12 mol) in glacial acetic acid, and the solution is allowed to stand (12 h). After saturation with dry HCl and pouring into diethyl ether the semi-solid which separates is wa.shed with ether, taken up in methanol, and reprecipitated as a fine, white solid (12.7g, 53%) by addition of ether. The hydrochloride is made basic with ammonia (d. 0.88) and extracted with chloroform. The organic extracts are dried (MgS04), the solvent is removed, and the solid product recrystallized from acetone, to 

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The formation of l-benzyl-4,5-dimethylimidazolin-2-one (107) when acetic anhydride reacts with l-benzyl-4,5-dimethylimidazole 3-oxide parallels similar reactions in the pyridine series (Scheme 47). 

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