N-bromobutanimide → Ethyl 2-(2-bromothiophen-3-yl)acetate

To a solution of ethyl 2-(thiophen-3-yl)acetate (1, 20.30 g, 119.25 mmol) in THF (150 mL) was added NBS (21.23 g, 119.25 mmol) over a period of 5 hours at 0° C., and then the mixture was warmed up to room temperature, stirring continuously for 24 hours. The solvent was removed in vacuo, and the residue was dissolved in EtOAc (150 mL) and washed with brine (4×30 mL). The organic layer was dried over MgSO4, filtered, and then concentrated in vacuo. MPLC purification (Hex/EtOAc 5:1) of the residue gave ethyl 2-(2-bromothiophen-3-yl)acetate as a colorless oil (24.00 g, 81%). 1H NMR (400 MHz, CDCl3) δ 7.23 (d, J=5.4 Hz, 1H), 6.93 (d, J=5.4 Hz, 1H), 4.17 (q, J=7.2 Hz, 2H), 3.61 (s, 2H), and 1.27 (t, J=7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 170.37, 133.84, 128.90, 125.93, 111.78, 61.32, 35.30, and 14.43.

1. customThe solvent was removed in vacuo
2. dissolutionthe residue was dissolved in EtOAc (150 mL)
3. washwashed with brine (4×30 mL)
4. dry with materialThe organic layer was dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customMPLC purification (Hex/EtOAc 5:1) of the residue

ORD record

ord-f883727cfec24a658eedab0a7a4a4840

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08404728B2