Hydrochloric Acid → Benzoic Acid

To methyl 4-(5-(4-(perfluoroethoxy)phenyl)-1,3,4-oxadiazol-2-yl)benzoate (1.07 g, 2.58 mmol) was added MeOH (26 mL) (starting material remained partially insoluble). A solution of 2 N NaOH (5.2 mL, 10.33 mmol) was added, and the reaction was stirred at room temperature for 18 h. Stirring had become hindered overnight due to the formation of solid. LC/MS showed 25% conversion to product. The reaction mixture was diluted with MeOH and additional 2 N NaOH (20 mL) was added and the reaction was heated to 45° C. for 24 h. The reaction was cooled and neutralized with 2 N HCl (20 mL). Some of the MeOH was concentrated off in vacuo, causing the product to precipitate. The white precipitate was vacuum filtered and dried in a vacuum oven at 45° C. to provide 44544-(perfluoroethoxy)phenyl)-1,3,4-oxadiazol-2-yl)benzoic acid as a white solid (760 mg, 90% purity, 66%): mp 301-307° C.; 1H NMR (400 MHz, DMSO-d6) δ 13.40 (s, 1H), 8.34-8.26 (m, 4H), 8.18 (d, J=8.6 Hz, 2H), 7.68 (d, J=8.8 Hz, 2H); 19F NMR (376 MHz, DMSO-d6) δ −85.25, −86.89; ESIMS m/z 401 ([M+H]+).

1. stirringStirring
2. waithad become hindered overnight due to the formation of solid
3. additionwas added
4. temperaturethe reaction was heated to 45° C. for 24 h
5. temperatureThe reaction was cooled
6. concentrationSome of the MeOH was concentrated off in vacuo
7. customto precipitate
8. filtrationfiltered
9. customdried in a vacuum oven at 45° C.

ORD record

ord-b9428d94bc8a4fedb2ef1e8220fc303e

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09440964B2