Sodium hydride → tert-butyl{1-[2-(5,7-difluoro-2-oxoquinoxalin-1(2H)-yl)ethyl]piperidin-4-yl}carbamate

Participants

Reaction Steps

A mixture of 5,7-difluoroquinoxalin-2(1H)-one and 6,8-difluoroquinoxalin-2(1H)-one (Intermediate 195) (1.05 g, 5.77 mmol) was deprotonated with sodium hydride (0.31 g, 60% in oil, 7.75 mmol) and alkylated with 2-{4-[(tert-butoxycarbonyl)amino]piperidin-1-yl}ethyl methanesulfonate (Intermediate 6) (5.8 mmol) as described for Intermediate 2. The residue obtained after aqueous workup was titurated in diethyl ether and filtered yielding 0.73 g of tert-butyl {1-[2-(5,7-difluoro-2-oxoquinoxalin-1(2H)-yl)ethyl]piperidin-4-yl}carbamate (Intermediate 193). The filtrate was concentrated and the residue was purified by chromatography on silica gel with 0-20% acetone in dichloromethane to yield 111 mg of tert-butyl {1-[2-(6,8-difluoro-2-oxoquinoxalin-1(2H)-yl)ethyl]piperidin-4-yl}carbamate (Intermediate 194).

Provenance & Evidence