Ethyl 3,5-dimethylimidazole

Sulfonyl chloride Dansyl chloride, 1,2 -dimethylimidazole-4-chloride, pyridine-3-sulfonyl chloride 4-(l-H-pyrazol-l-yl)benzenesul-fonyl chloride [62] 10-Ethyl-acridine-2-sulfonyl chloride T631 Phenolic OH LC-ESP/MS/ MS LC-APCP/ MS/MS... 

A mixmre of acetaldoxime (20.0 g, 0.34 mol) and butanedione monoxime (34.2 g, 0.34 mol) is warmed to give a homogeneous solution, then allowed to stand at room temperature (2 days), refluxed (1 h), cooled, and diluted with diethyl ether (500 ml). The product precipitates as a tan solid (30.4 g, 63%), m.p. 194 C (dec.). Similarly prepared in 65% yield is 2-ethyl-l-hydroxy-4,5-dimethylimidazole 3-oxide. 

The N-alkylation of imidazoles with alcohols were carried out in the vapor phase over a series of zeolites. H-Y was found most active. Thus, a 100% yield of N-methyl- and N-ethylimidazole was obtained over H-Y at 553 K and 573 K, respectively. H-Y also showed a high activity for the alkylation of 2-methylimidazole with methanol or ethanol. In the methylation of 4(5)-methylimidazole, the products were 1,4- and 1,5-dimethylimidazole. The former was the predominant product over H-Beta(78%) and H-ZSM-5(72.5%), while the latter was the main product over H-Y(89% selectivity). The similar regioselectivity was also found in the ethylation of 4(5)-methylimidazole. 

A soln. of propargylamine in dioxane added dropwise to a refluxing soln. of ethyl acetimidate and a little p-toluenesulfonic acid in the same solvent, and refluxing continued 0.5 hr. 2,5(4)-dimethylimidazole. Y 87%. F. e. and methods s. E. Eloy, A. Deryckere, and J. P. Maffrand, Chim. Ther. 9, 602 (1974). 

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