Acetic Acid → 2-(4-(Perfluoroethoxy)phenyl)-1,3,4-oxadiazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-(perfluoroethoxy)benzohydrazide (3.17 g, 11.7 mmol) in trimethyl orthoformate (11.6 mL, 106 mmol) and acetic acid (0.13 mL, 2.35 mmol) was heated at 120° C. for 5 hours. The reaction was diluted with MeOH (15 mL) and poured into a beaker containing ice water (150 mL). The white precipitate was vacuum filtered and dried in a vacuum oven to provide 166 mg of 2-(4-(perfluoroethoxy)phenyl)-1,3,4-oxadiazole as an off-white solid. An orange precipitate had formed in the aqueous filtrate and was collected by vacuum filtration and adsorbed onto silica gel. Purification by flash chromatography (0-40% EtOAc/hexanes) provided 2.02 g of 2-(4-(perfluoroethoxy)phenyl)-1,3,4-oxadiazole as an off-white solid giving a combined yield of 2.186 g (67%): mp 87-89° C.; 1H NMR (400 MHz, CDCl3) δ 8.49 (s, 1H), 8.28-8.05 (m, 2H), 7.40 (d, J=8.9 Hz, 2H); 19F NMR (376 MHz, CDCl3) δ −85.98, −87.82; ESIMS m/z 280 ([M+H]+).

Provenance & Evidence