Iodoethane → 3-Ethylhexahydro-3-(3-hydroxyphenyl)-1-methyl-2H-azepin-2-one

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Reaction Conditions

Reaction Steps

Butyl lithium (77 ml of a 1.4 molar solution in hexane) was added to a solution of diisopropylamine (14.8 ml) in dry tetrahydrofuran (20 ml) at -10° C. under nitrogen. The mixture was stirred at -10° C. for ten minutes and finely powdered hexahydro-3-(3-hydroxyphenyl)-1-methyl-2H-azepin-2-one (11 g) was added. Tetrahydrofuran (500 ml) was added and the mixture heated under reflux for 3 hours. After cooling, ethyl iodide (8.2 g) was added and the mixture again heated under reflux for 3 hours. Water (20 ml) was then cautiously added to the cooled solution and the mixture evaporated to a brown residue. After dissolving in water the mixture was extracted with dichloromethane and the dichloromethane extracted in turn with 2 M sodium hydroxide. The aqueous and sodium hydroxide washings were combined and acidified with concentrated hydrochloric acid. The precipitated solid was filtered, washed with water, dried and recrystallised from ethyl acetate, affording 8.72 g of the title compound as white crystals, m.p. 178°-180° C.

Provenance & Evidence