Sodium triacetoxyborohydride → 6-[({1-[2-(5,7-Difluoro-2-oxoquinoxalin-1(2H)-yl)ethyl]piperidin-4-yl}amino)methyl]-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-[2-(4-aminopiperidin-1-yl)ethyl]-5,7-difluoroquinoxalin-2(1H)-one (Intermediate 192, 0.158 g) in methanol (10 mL) were added 3 Å molecular sieve power (0.15 g) and 3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde (WO 2004/058144) (92 mg). After 2 hours at reflux, the reaction was cooled to 0° C. and NaBH(OAc)3 (0.19 g) was added. The reaction was allowed to warm to room temperature and was stirred overnight. It was diluted with ethyl acetate, filtered, washed with saturated solutions of Na2CO3 and brine, dried over sodium sulfate and concentrated. Chromatography on silica gel with 0-20% methanol in dichloromethane. Fractions containing product were collected, concentrated, dissolved in a minimum of CH2Cl2, precipitated with diethyl ether, and filtered to yield 104 mg of product.

Provenance & Evidence