Phosgene → HCID 90411618, compound

Participants

Reaction Steps

N′-(4-fluorophenyl)thiophene-2-carbohydrazide (575 mg, 2.43 mmol) was dissolved in dichloromethane (14 mL) and tetrahydrofuran (10 mL) in a glass flask. The flask was cooled in ice. Phosgene (20% in toluene, 3.42 mL, 6.49 mmol, 2.67 eq.) was added, and the solution was stirred overnight under a nitrogen atmosphere, allowing it to warm to room temperature. Ethyl acetate (40 mL) was added, and the solution was then washed with water (2×25 mL) and brine (25 mL). The solution was dried over magnesium sulfate, filtered and concentrated in vacuo to give 0.59 grams of crude product as a light brown solid. Purification using ISCO flash chromatography (silica, gradient heptanes/ethyl acetate) gave 3-(4-fluorophenyl)-5-(thiophen-2-yl)-1,3,4-oxadiazol-2(3H)-one (210 mg, 0.800 mmol, yield 33.0%) as an off-white solid with an HPLC purity of 99.7%. LC-MS [M+H] 263.02 (C12H7FN2O2S+H, expected 263.02). The 1H-NMR spectrum was in accordance with the chemical structure.

Provenance & Evidence