Water → 5-cyanofuran-2-carboxylic Acid

Temperature

85 °C

To a solution of 2-fornyl-5-furancarboxylic acid (0.28 g, 2.0 mol) in pyridine (5.0 mL) was added hydroxylamine hydrochloride (“NH2OH.HCl”) (0.27 g, 4.0 mol). The mixture was heated to 85° C. before the addition of acetic anhydride (4.0 ml). The reaction mixture was stirred at 85° C. for 3 h, cooled to 60° C. and poured into water (25 mL). The mixture was cooled to room temperature and stirred overnight (the pH of the solution was measured to be 5-6). The impurities were extracted with a solution of 4/1 DCM/isopropanol (3×30 mL). The aqueous layer was then basified with NaOH solution (2 N) to a pH of about 9, and the pyridine was extracted with a solution of 4/1 DCM/isopropanol (3×30 mL). The aqueous solution was then acidified to a pH of about 2 and the product was extracted with a solution of 3/1 DCM/isopropanol (3×50 mL). The combined organic extracts were dried over MgSO4, and the solvent was evaporated to afforded the pure product as a light brown solid in 90% yield. 1H NMR (DMSO-d6): δ 13.80 (bs, 1H), 7.75 (d, 1H), 7.40 (d, 1H). IR (neat): (cm−1) 3200, 2250, 1053, 1025, 1006.

1. temperaturecooled to 60° C.
2. temperatureThe mixture was cooled to room temperature
3. stirringstirred overnight (the pH of the solution
4. extractionThe impurities were extracted with a solution of 4/1 DCM/isopropanol (3×30 mL)
5. extractionthe pyridine was extracted with a solution of 4/1 DCM/isopropanol (3×30 mL)
6. extractionthe product was extracted with a solution of 3/1 DCM/isopropanol (3×50 mL)
7. dry with materialThe combined organic extracts were dried over MgSO4
8. customthe solvent was evaporated

ORD record

ord-be24f5622c79459b9ed36cb436d0be32

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07429603B2