Hydrochloric Acid → 5-cyanofuran-2-carboxylic Acid

Temperature

85 °C

To a flask with a stir bar and Vigreaux column under Ar was added 2-formyl-5-furancarboxylic acid (2.8 g, 20 mmol), hydroxylamine hydrochloride (2.7 g, 40 mmol), and dry pyridine (50 mL). The mixture was heated to 85° C., acetic anhydride (40 mL) was added and the mixture was stirred for 3 h. After cooling to 60° C., water (250 mL) was added and the mixture was stirred at RT for 70 h. The mixture was acidified to pH 2 with concentrated hydrochloric acid and extracted with 3:1 dichloromethane-isopropanol (8×100 mL). The combined organic layers were washed with water (100 mL), brine (100 mL), dried over anh sodium sulfate and concentrated in vacuo to afford the title compound as a tan solid (1.26 g, 46%). 1H-NMR (CD3OD; 400 MHz): δ 14.05 (br s, 1H), 7.74 (d, 1H, J=3.8 Hz), 7.42 (d, 1H, J=3.8 Hz).

1. temperatureAfter cooling to 60° C.
2. stirringthe mixture was stirred at RT for 70 h
3. extractionextracted with 3:1 dichloromethane-isopropanol (8×100 mL)
4. washThe combined organic layers were washed with water (100 mL), brine (100 mL)
5. dry with materialdried over anh sodium sulfate
6. concentrationconcentrated in vacuo

ORD record

ord-359f6164b72b4e60900eec4e3bf52a18

Source dataset

uspto-grants-2010_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07645755B2