酰胺缩醛法合成1,2,4-三唑-5-酮

Synthesis of 1,2,4-triazolin-5-ketone by amide acetals

用甲苯作溶剂,使氨基甲酸乙酯和N,N-二甲基甲酰胺二甲缩醛在90℃反应1 5 h,得到中间体N,N-二甲基-N'-乙 氧羰基甲脒,然后减压除去甲苯,再加入肼、乙酸,在100℃反应2 h,减胜除去乙酸,得到1,2,4-三唑-5-酮及其衍生物,产率大 于75％。

Ethyl carbamate reacted with N, N-dimethylformamide dimethyl acetal in toluene at 90℃ for 1.5 h to give N, N-dimethyl-N'-ethoxycarbonyl formamidine,the intermediate. After removing the toluene from the reaction system,the intermediate reacted with hydrazine in acetic acid at 100℃ for 2 h to give 1 ,2 ,4-triazolm-5-ketone in a yield of more than 75% .