Yield:482577-59-3 260 g

Reaction Conditions:

with potassium carbonate in water;ethyl acetate for 2 h;Reflux;

Steps:

2 Preparation of secondary amine methyl ester hydrochloride:
800 ml of drinking water and 240 g of potassium carbonate were charged into the reactor,Stirring into the 2000ml ethyl acetate,168 g of L-valine methyl ester hydrochloride prepared in Example 1 and 200 g of bromo-sarbazine.Heated to reflux and maintained reflux for 2 hours.Cold to 20 ~ 40 after standing, sub-water,The organic phase was acidified with hydrochloric acid to pH = 1. Filtration at 70 ± 5 ° C,Vacuum degree of -0.09Mpa under the drying, the secondary amine methyl ester hydrochloride 260g, purity 99.6%.

References:

Tsingtao Xuejie Zhuji Co., Ltd.;Chen Likun;Liu Linxue;Li Jianmin CN103923028, 2017, B Location in patent:Paragraph 0055-0056