Ammonium Chloride → (9S)-2,3-Dimethyl-9-phenyl-5,6,7,8,9,10-hexahydroimidazo[1,2-h][1,7]naphthyridin-7-one

Participants

Reaction Conditions

Reaction Steps

9.7 g (51.6 mmol) of ethyl (S)-3-amino-3-phenylpropionate, 8.5 g (51.6 mmol) of 2,3-dimethyl-6,7-dihydro-5H-imidazo[1,2-a]pyridin-8-one and 0.26 g (1.3 mmol) of p-toluenesulfonic acid monohydrate are heated under reflux in 50 ml of toluene in a water separator. After water no longer separates, the reaction mixture is cooled to 0° C. and diluted with 100 ml of tetrahydrofuran. 7.24 g (64.5 mmol) of potassium tert-butoxide are then introduced and the mixture is stirred at room temperature for 16 h. 150 ml of saturated ammonium chloride solution are added to the reaction mixture, the organic phase is separated off and the aqueous phase is extracted with 300 ml of ethyl acetate. The combined organic phases are washed with 250 ml of water, dried over sodium sulfate and evaporated. 13.27 g (88%) of the title compound are isolated as a red-brown oil. An analytical sample is obtained by crystallization using diethyl ether (red solid, m.p. 134° C.).

Provenance & Evidence