Pyridine → Isobutyric acid 5-methyl-7-(3-methyl-1,2,4-oxadiazol-5-yl)-6-oxo-5,6-dihydro-pyrido[2,3-b]pyrazin-8-yl ester

Participants

Reaction Steps

To a solution of 8-hydroxy-5-methyl-7-(3-methyl-1,2,4-oxadiazol-5-yl)-5H-pyrido[2,3-b]pyrazin-6-one (Example 7.4) (0.044 g) and pyridine (0.018 ml) in dichloromethane (1 ml) was added dropwise isobutyryl chloride (0.022 ml). The reaction mixture was stirred at ambient temperature for 4 hours and then stored at ambient temperature for 16 hours. The reaction mixture was diluted with more dichloromethane and the mixture was washed successively with aqueous sodium hydrogen carbonate (saturated), aqueous ammonium chloride (saturated) and brine. The organic fraction was dried over magnesium sulfate and concentrated. The residue was purified by column chromatography on silica gel (eluent: ethyl acetate/hexane 1:1) to give Compound No. B6 of Table 6 as a pale yellow solid (0.020 g).

Provenance & Evidence