Hydrochloric Acid → 5-cyanofuran-2-carboxylic Acid

Temperatur

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-Eintrag

ord-c748a3d7b1ef49f59b4233571c04724a

Quelldatensatz

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07427683B2