Yield:134272-64-3 95.2%

Reaction Conditions:

with hydrogenchloride in ethyl acetate at 20; for 8 h;

Steps:

8 1-(2-Amino-ethyl)-pyrrole-2,5-dione Hydrochloride
N-(2-((tert-Butoxycarbonyl)amino)ethyl)maleimide (750 mg, 3.12 mmol) was dissolved in 4 M HCl in ethyl acetate (20 mL) and stirred for 8 h at room temperature. Then, addition of diethyl ether at 0 °C. provided the title compound as a white precipitate (524 mg, 2.97 mmol, 95.2% yield). ¹H NMR (500 MHz, MeOD): δ 6.90 (s, 2H), 3.83-3.79 (m, 2H), 3.17-3.13 (m, 2H).

References:

HANGZHOU DAC BIOTECH CO., LTD.;SUN, Sanxing;ZHAO, Robert Yongxin;LI, Xing;GUO, Huihui;JIA, Junxiang;XIE, Hongsheng;ZHOU, Xiaomai;HUANG, Yuanyuan;YANG, Qingliang;ZHUO, Xiaotao;YE, Hangbo;GAI, Shun;QU, Lan;LI, Wenjun;LIN, Chen US2019/125894, 2019, A1 Location in patent:Paragraph 0162-0163

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