Four new 4-ethoxy-2-substituted imidazoles (1) were synthesized and high reactivity toward electrophiles was observed at the 5-position rather than the N atoms. For example, 1 reacted with dimethyl acetylenedicarboxylate to afford dimethyl (4-ethoxyimidazol-5-yl)fumarates (6) and-maleates (5). When 6 was treated with acid, a novel ring transformation occurred to give methyl (6-ethoxycarbonyl-3, 4-dihydro-4-oxopyrimidin-5-yl)acetates (12).
合成了四种新的4-乙氧基-2-取代
咪唑(1),并观察到在5位对电亲体表现出高反应性,而不是对氮原子。例如,1与二甲基
乙炔二
羧酸酯反应,得到二甲基(4-乙氧基
咪唑-5-基)
富马酸酯(6)和
山梨酸酯(5)。当6与酸反应时,发生了一种新颖的环转化,生成
乙酸盐(12)。