Acetic Acid → 7-methoxy-3,4-dihydro-2H-1-benzopyran-4-carboxylic acid

To 7-methoxy-4-(trimethylsilyloxy)-3,4-dihydro-2H-chromene-4-carbonitrile (1.62 g, 5.84 mmol) in acetic acid (15 mL) and HCl (15 mL) was added SnCl2 dihydrate (5.27 g, 23.4 mmol). The reaction was heated at 130° C. for 1 day. The reaction was cooled, diluted with dichloromethane (50 mL) and washed with water (50 mL) and brine (50 mL). The combined organic layers were dried over magnesium sulfate and concentrated. The residue was chromatographed over silica gel using a gradient of 0.5% MeOH/CH2Cl2 containing 0.5% acetic acid to 10% MeOH/CH2Cl2 containing 0.5% acetic acid to provide the title compound (0.95 g, 78.1% yield).

1. temperatureThe reaction was cooled
2. washwashed with water (50 mL) and brine (50 mL)
3. dry with materialThe combined organic layers were dried over magnesium sulfate
4. concentrationconcentrated
5. customThe residue was chromatographed over silica gel using a gradient of 0.5% MeOH/CH2Cl2 containing 0.5% acetic acid to 10% MeOH/CH2Cl2 containing 0.5% acetic acid

ORD record

ord-7a7e4308e6e94d5ebe82341b93ae9604

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08716498B2