Tetrahydrofuran → 2(3H)-Benzoxazolone

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]+.

1. customThe reaction vessel was flushed with N2
2. additionEt3N (1.25 mL) and COCl2 (1.20 mL of a 20% solution in toluene, 2.25 mmol) were added
3. stirringthe reaction stirred for 2 hours
4. customThe reaction was quenched with saturated NaHCO3
5. filtrationfiltered
6. customthe THF removed under reduced pressure
7. extractionThe aqueous solution was extracted with EtOAc
8. dry with materialThe organic layer was dried (Na2SO4)
9. customthe solvent removed under reduced pressure
10. customPurification by chromatography (silica gel 1:2 to 4:5 EtOAc: hexanes)

ORD record

ord-5b73a07b9b3543fdaab704a497abb33a

Source dataset

uspto-grants-2004_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06828341B2