Hydrochloric Acid → 5-cyanofuran-2-carboxylic Acid

Temperature

85 °C

To 2.8 g of 2-formyl-5-furancarboxylic acid (20 mmol) and 2.7 g of hydroxylamine hydrochloride (40 mmol) under Ar was added 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-c748a3d7b1ef49f59b4233571c04724a

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07427683B2