Heptanoic acid, 7-oxo-, ethyl ester → rac-Ethyl 7-(7-methoxy-2,3-dip-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoate

Participants

Reaction Steps

rac-7-Methoxy-2,3-dip-tolyl-5,6,7,8-tetrahydropyrido[2,3-b]pyrazine (Intermediate K) (80 mg, 0.232 mmol) in dry DCE (4 ml) at RT under nitrogen was treated with DIPEA (0.044 ml, 0.255 mmol) followed by ethyl 7-oxoheptanoate (80 mg, 0.463 mmol). The resulting mixture was stirred at RT for 10 minutes and treated with sodium triacetoxyborohydride (245 mg, 1.158 mmol). The mixture was heated at 60° C. for 16 hours. A further portion of sodium triacetoxyborohydride (245 mg, 1.158 mmol) was added and the mixture was heated at 50° C. for 3 days. After cooling to RT, the reaction mixture was diluted with DCM (50 ml) and washed with water (×2). The organic portion was isolated using a phase separating cartridge and the solvent was removed in vacuo. Purification of the crude product by chromatography on silica eluting with 0-20% EtOAc/iso-hexane afforded the title compound.

Provenance & Evidence