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

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Reaction Steps

To a solution of 2,3-dip-tolyl-5,6-dihydropyrido[2,3-b]pyrazine (Example 8.2 step 1) (3.88 g, 12.38 mmol) in DCE (70 ml) was added ethyl 7-oxoheptanoate (6.40 g, 37.1 mmol) followed by sodium triacetoxyborohydride (10.4 g, 49.1 mmol). The reaction mixture was stirred for 2 days at room temperature under an atmosphere of nitrogen. The reaction mixture was diluted with water (70 ml) and extracted with EtOAc (3×70 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated in vacuo. The crude product was purified by chromatography on silica eluting with EtOAc/iso-hexane, followed by further purification using reverse phase chromatography eluting with MeCN/water (0.1% TFA) to afford the title compound;

Provenance & Evidence