Cesium carbonate → (+/-)-7-(2-methoxy-3,5-dimethylpyridin-4-yl)-1-(tetrahydrofuran-3-yl)-1H-pyrazolo[4,3-c]quinolin-4(5H)-one

Participants

Reaction Conditions

Reaction Steps

A mixture of (±)-5-(2,4-dimethoxybenzyl)-1-(tetrahydrofuran-3-yl)-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazolo[4,3-c]quinolin-4(5H)-one obtained in Preparation Example 5 (219 mg), 4-bromo-2-methoxy-3,5-dimethylpyridine obtained in Preparation Example 28 (134 mg), Pd(PPh3)4 (23.8 mg) and cesium carbonate (403 mg) was reacted in a mixed solvent of 1,4-dioxane (8 mL) and water (2 mL) using a microwave reactor at 130° C. for 70 minutes. The reaction mixture was cooled to mom temperature and then directly purified by silica gel column chromatography (ethyl acetate/n-heptane, 10% to 90%). The resulting coupling product was dissolved in TFA (4 mL), and the mixture was stirred at 70° C. for two hours. The reaction mixture was cooled to room temperature and then concentrated under reduced pressure. A saturated aqueous sodium bicarbonate solution was added to the residue, followed by extraction with ethyl acetate. The organic layer was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (DCM, 100%, then ethyl acetate/n-heptane, 50% to 100%) to give the title compound (78 mg).

Provenance & Evidence