Acetic Acid → [4-(1,3,4-oxadiazol-2-yl)phenyl]boronic Acid

A solution of 2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1,3,4-oxadiazole (0.504 g, 1.85 mmol) in THF (10 mL) and water (5 mL) was treated with sodium periodate (1.19 g, 5.56 mmol). The resultant slurry was stirred at RT for 5 h. Glacial acetic acid (0.21 mL, 3.7 mmol) was added and the mixture was stirred for 1 h and filtered. The filtered solid was washed with ethyl acetate (75 mL) and THF-methanol (1:1, 100 mL) and the filtrates were concentrated in vacuo to a white solid. The solid was suspended in THF (75 mL) and 10 mL of 0.1 M aq HCl and was sonicated to promote dissolution. The trace of insolubles were filtered and the organic layer was diluted with ethyl acetate (25 mL), washed with 0.1 M Na2S2O3 (2×20 mL), water (2×20 mL) and brine (20 mL), dried (Na2SO4) and concentrated in vacuo to provide 4-(1,3,4-oxadiazol-2-yl)phenylboronic acid (304 mg, 86% yield) as a white powder. 1H NMR (400 MHz, DMSO-d6): δ 9.37 (s, 1 H), 8.32 (s, 2 H), 7.99 (s, 4 H).

1. stirringthe mixture was stirred for 1 h
2. filtrationfiltered
3. washThe filtered solid was washed with ethyl acetate (75 mL) and THF-methanol (1:1, 100 mL)
4. concentrationthe filtrates were concentrated in vacuo to a white solid
5. custom10 mL of 0.1 M aq HCl and was sonicated
6. dissolutiondissolution
7. filtrationThe trace of insolubles were filtered
8. additionthe organic layer was diluted with ethyl acetate (25 mL)
9. washwashed with 0.1 M Na2S2O3 (2×20 mL), water (2×20 mL) and brine (20 mL)
10. dry with materialdried (Na2SO4)
11. concentrationconcentrated in vacuo

ORD record

ord-f049f3639fe34684a357a031ad6d49b4

Source dataset

uspto-grants-2012_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08188113B2