Tetrahydrofuran → 2(3H)-Benzoxazolone

Participants

Reaction Steps

A mixture of oxazolidinone of formula 32 (1.00 g, 2.25 mmol) and 10% Pd/C (150 mg) in THF (50 mL) was shaken under an atmosphere of H2 at 50 psi for 3 hours. The reaction vessel was flushed with N2, then Et3N (1.25 mL) and COCl2 (1.20 mL of a 20% solution in toluene, 2.25 mmol) were added and the reaction stirred for 2 hours. The reaction was quenched with saturated NaHCO3, filtered, and the THF removed under reduced pressure. The aqueous solution was extracted with EtOAc. The organic layer was dried (Na2SO4) and the solvent removed under reduced pressure. Purification by chromatography (silica gel 1:2 to 4:5 EtOAc: hexanes) gave a benzoxazolidinone intermediate (510 mg, 65%): 1H NMR (500 MHz, CD3OD+CDCl3) δ 7.59 (br s, 1H), 7.22 (d, J=8 Hz, 1H), 7.06 (d, J=8 Hz, 1H), 4.76-4.70 (m, 2H), 4.16-4.07 (m, 1H), 3.88-3.84 (m, 1H), 3.44 (br s, 2H), 1.41 (s, 9H); CI-MS (m/z): 350 [M+H]+.

Provenance & Evidence