Methanol → 2-Difluoromethyl-5-hydroxy-pyran-4-one

Participants

Reaction Steps

To an ice-salt cooled, clear solution of 5-benzyloxy-2-difluoromethyl-pyran-4-one (252 mg, 1 mmol) in CH2Cl2 (4 mL) was added dropwise a solution of 1.0 M BBr3 in CH2Cl2 (1 mL, 1 mmol) diluted with CH2Cl2 (1 mL). After 10 min, TLC analysis of the reaction mixture using a mixture of CH2Cl2 and MeOH (20/1, v/v) as eluant indicated consumption of the starting material. The reaction mixture was quenched with MeOH (5 mL), and evaporated to dryness. The residual oil was taken up in ethyl acetate (30 mL), and the organic layer was washed with brine (2×10 mL), dried over sodium sulfate. The mixture was filtered, and the filtrate was concentrated in vacuo to give a solid. The solid was triturated with ether, and was then collected by suction filtration. The title compound was obtained as an off-white solid (80 mg, 50% yield). The purity (peak area percent is 97.3%) of this material was analysed by HPLC Method 1 as described above. 1H NMR (400 MHz, DMSO-D6) δ (ppm): 9.59 (s, 1H), 8.22 (s, 1H), 6.93 (t, J=52.8 Hz, 1H, CF2H), 6.76 (s, 1H).

Provenance & Evidence