2-Methyl-2-butene → 6-Cyclopentyloxy-7-methoxy-1-(3-methoxy-benzoyl)-isoquinoline-4-carboxylic acid

Participants

Reaction Steps

To a stirred solution of afforded 6-cyclopentyloxy-7-methoxy-1-(3-methoxy-benzoyl)-isoquinoline-4-carbaldehyde (200 mg, 0.49 mmol) in t-butanol (2 mL) and water (2 mL) solution was added sodium dihydrogenphosphate monohydrate (184 mg, 1.33 mmol), 2-methyl-2-butene (0.226 mL, 2.00 mmol) and sodium chlorite (181 mg, 2.00 mmol) at room temperature. The reaction suspension was then stirred at room temperature for 14 hrs. The resulting two-phase mixture was partitioned between dichloromethane and water and acidified to pH=3 by addition of acetic acid. The aqueous phase was then extracted with dichloromethane (3×20 mL). The combined extracts were washed with saturated aqueous sodium chloride solution (30 mL), dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to afford a brown semi-solid oil. The crude product was recrystallized in ethyl acetate and hexane to afford 6-cyclopentyloxy-7-methoxy-1-(3-methoxy-benzoyl)-isoquinoline-4-carboxylic acid (120 mg, 58% yield) as a yellow solid: HR-MS m/e calcd for C24H23N1O6 (M−H+) 421.1525, found 421.1526; 1H NMR (300 MHz) compatible.

Provenance & Evidence