Heptanoic acid, 7-oxo-, ethyl ester → HCID 89689894, compound

Participants

Reaction Steps

To a solution of 8-methyl-2,3-di-p-tolyl-5,6,7,8-tetrahydropyrido[2,3-b]pyrazin-8-ol (Intermediate G)(240 mg, 0.695 mmol) in DCE (10 ml) was added ethyl 7-oxoheptanoate (359 mg, 2.084 mmol) followed by sodium triacetoxyborohydride (442 mg, 2.084 mmol) and the resulting mixture was left to stir overnight at room temperature under an atmosphere of nitrogen. The reaction mixture was diluted with water and extracted with EtOAc (2×20 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure to give a brown oil. The oil was purified by chromatography on silica eluting with EtOAc in iso-hexane to afford ethyl 7-(8-hydroxy-8-methyl-2,3-di-p-tolyl-7,8-dihydropyrido[3,2-b]pyrazin-5(6H)-yl)heptanoate (Intermediate 15.1). This compound was passed through a 5 g Isolute® SCX-2 SPE cartridge (primed with MeOH—20 ml) and washing with MeOH (30 ml). The product was eluted with 2M NH3 in MeOH (20 ml). The basic eluent was concentrated under reduced pressure to afford a 1:2 mixture of ethyl 7-(8-hydroxy-8-methyl-2,3-di-p-tolyl-7,8-dihydropyrido[3,2-b]pyrazin-5(6H)-yl)heptanoate compound: ethyl 7-(8-methoxy-8-methyl-2,3-d i-p-tolyl-7,8-dihydropyrido[3,2-b]pyrazin-5(6H)-yl)heptanoate;

Provenance & Evidence