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Free keywords:
2H-Imidazole;
1,4-Diazadienes;
[4 + 2] Cycloadditions
Abstract:
2,2-Diethyl-4,5-dimethyl-2H-imidazole 1, formally a 1,4-di-azadiene, does not produce [4 + 2] cycloadducts with various electronically-different dienophiles. In the presence of tri-fluoroacetic acid, it tautomerizes to 2,2-diethyl-4-methyl-5-methylene-3-imidazoline 2 and forms a dimer, the structure of which was determined by X-ray crystallography.