Ethanedioic acid, monoethyl ester, hydrazide synthesis

Yield: 94%

Reaction Conditions:

with hydrazine hydrate in ethanol;water at -25 - 5;Inert atmosphere;Solvent;

Steps:

1 Preparation of monoethyl oxalate hydrazide(Compound-8,R1=C2H5)
General procedure: Under the protection of nitrogen, diethyl oxalate (300.0 g, 2.05 mol) was dissolved in 1400 ml of ethanol, and the temperature was lowered to -25 ° C to -20 ° C, and hydrazine hydrate (1 hydrate) was added dropwise (99.6 g, 1.96 mol, > 98%) solution of ethanol (1050 ml). After completion of the dropwise addition, the reaction solution was stirred at 0 ° C to 5 ° C overnight. After completion of the reaction, the mixture was filtered, and the filter cake was washed with 120 ml of ethanol, and the filtrate was concentrated to dryness under reduced pressure. 243.5 g of ethyl oxalate hydrazide (Compound-8) was obtained.

References:

Zhejiang Puluokangyu Pharmaceutical Co., Ltd.;Wang Zheqing;Yang Yongbing;Tan Yongwang;Chen Yunfeng;Lu Xinxin;Hu Xizhong;Li Tiantian CN104974106, 2019, B Location in patent:Paragraph 0076-0080