反应详情

A solution of {3-[3-(tert-butoxycarbonyl-cyclopropylmethyl-amino)-propylamino]-2-oxo-2H-pyrazin-1-yl}-acetic acid ethyl ester (250 mg, 0.61 mmol, preparation described in example 21, step D) and N-chlorosuccinimide (73 mg, 0.55 mmol) in 1,2-dichloroethane (4.2 ml) was heated to 80° C. for 1.5 h. Additional N-chlorosuccinimide (8 mg) was added and the reaction mixture was heated for 1 h. Concentration and flash chromatography (silica gel, hexane-ethyl acetate, 80:20) gave {3-[3-(tert-butoxycarbonyl-cyclopropylmethyl-amino)-propylamino]-6-chloro-2-oxo-2H-pyrazin-1-yl}-acetic acid ethyl ester (0.22 g, 81%); 1H NMR (CDCl3, 400 MHz) δ 6.94 (s, 1H), 4.90 (s, 2H), 4.26 (q, 2H, J=7.1 Hz), 3.40 (m, 4H), 3.10 (m, 2H), 1.87 (m, 2H), 1.48 (s, 9H), 1.31 (t, 3H, J=7.1 Hz), 0.97 (m, 1H), 0.49 (m, 2H), 0.21 (m, 2H).

1. temperaturethe reaction mixture was heated for 1 h
2. concentrationConcentration and flash chromatography (silica gel, hexane-ethyl acetate, 80:20)