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-4357ba4ef0b1455f995d0164c86b58ed

Source dataset

uspto-grants-2013_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08569522B2