tert-Butanol → tert-Butyl thiophen-2-ylcarbamate

Temperature

90 °C

To a solution of thiophenecarboxylic acid (0.5 g, 3.90 mmol) in tBuOH (10 ml) was added Et3N (0.571 ml, 4.10 mmol) and DPPA (0.883 ml, 4.10 mmol). The solution was heated at 90° C. for 4 hours. The reaction mixture was cooled to RT and the solvent was removed in vacuo. The residue was treated with benzene and then the solution was washed with 5% citric acid, and sat'd NaHCO3. Solid was filtered off and the filtrate was washed with brine. The organic layer was dried (MgSO4), concentrated in vacuo and the residue was purified by silica gel column chromatography (EtOAc/hexanes) to obtain tert-butyl thiophen-2-ylcarbamate (0.39 g, 50% yield). 1H NMR (400 MHz, DMSO-d6): δ 10.4 (brs, 1H), 6.84 (dd, J=1.6, and 5.2 Hz, 1H), 6.75 (dd, J=4.0, and 5.6 Hz, 1H), 6.48 (dd, J=1.6, and 4.0 Hz, 2H), 1.45 (s, 9H); MS (ESI) m/z: 222.0 (M+22+H+).

1. temperatureThe reaction mixture was cooled to RT
2. customthe solvent was removed in vacuo
3. additionThe residue was treated with benzene
4. washthe solution was washed with 5% citric acid
5. filtrationSolid was filtered off
6. washthe filtrate was washed with brine
7. dry with materialThe organic layer was dried (MgSO4)
8. concentrationconcentrated in vacuo
9. customthe residue was purified by silica gel column chromatography (EtOAc/hexanes)

ORD record

ord-bdc6dee50bf7487fbe0adb885246e3fc

Source dataset

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08278331B2