反应详情

A mixture of 3-chloro-5-ethoxypyridine (6.5 g, 45.8 mmol), piperazine (19.7 g, 229 mmol), potassium tert-butoxide (11.2 g, 91.6 mmol) and 1,2-dimethoxyethane (150 ml) was stirred at reflux for 1 h. Aqueous sodium hydroxide (1 M, 100 ml) was added and the mixture was extracted two times with ethyl acetate (150 ml). Chromatography on silica gel with dichloromethane, methanol and conc. ammonia (89:10:1) gave the title compound. Yield 4.6 g, 48%. The corresponding salt was obtained by addition of a diethyl ether and methanol mixture (9:1) saturated with fumaric acid. Mp 160.0-161.2° C.

1. temperatureat reflux for 1 h
2. extractionthe mixture was extracted two times with ethyl acetate (150 ml)