Heptanoic acid, 7-oxo-, ethyl ester → (R)-Ethyl 7-(8-acetoxy-2,3-diphenyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoate

Participants

Reaction Steps

To a solution of (R)-2,3-diphenyl-5,6,7,8-tetrahydropyrido[2,3-b]pyrazin-8-yl acetate (Intermediate HBR) in DCE (7 ml) was added ethyl 7-oxoheptanoate (71.8 mg, 0.417 mmol) followed by sodium triacetoxyborohydride (236 mg, 1.112 mmol). The reaction mixture was left to stir at room temperature overnight under an atmosphere of nitrogen. A further portion of ethyl 7-oxoheptanoate (6 equivalents) was added and the reaction mixture was left to stir at RT for 4 days. The mixture was diluted with water (20 ml) and extracted with EtOAc (3×20 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated in vacuo. The resulting crude product was purified by chromatography on silica eluting with 0-40% EtOAc/iso-hexane to afford the title compound;

Provenance & Evidence