Sodium cyanoborohydride → tert-Butyl (2R,5S)-2-[2-(6-cyano-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethyl]-5-{[(3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazin-6-yl)methyl]amino}piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of tert-butyl (2R,5S)-5-amino-2-[2-(6-cyano-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethyl]piperidine-1-carboxylate (Intermediate 183, 0.14 g), 3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde (WO 2004/058144) (75 mg) and 3 Å molecular sieves powder (70 mg) in methanol (8 mL) was heated at 80° C. for 1 hour. The solution was cooled to 0° C. and NaCNBH3 (33 mg) was added. After stirring at room temperature overnight, the reaction was filtered and concentrated. The residue was purified chromatography on silica gel with a gradient of 0-5% methanol in methylene chloride to give 0.14 g.

Provenance & Evidence