1-(5-Bromothiophen-3-yl)ethan-1-one → HCID 68509357, compound

To a solution of ethyl-triphenyl-phosphonium bromide (27.0 mmol, 10.02 g) in anhydrous THF (90 mL) was added at 0° C. a solution of KOtBu (27.0 mmol, 27 mL, 1 M in THF). The solution was stirred for 1 h at room temperature, cooled down to −78° C. and treated with a solution of 1-(5-bromo-thiophen-3-yl)-ethanone (19.1 mmol, 3.92 g) in anhydrous THF (30 mL) at the temperature. The reaction mixture was slowly warmed to room temperature overnight with stirring. After dilution of the reaction mixture with EtOAc (200 mL), it was washed with water (70 mL×2) and brine (70 mL), dried (MgSO4) and concentrated in vacuo. Chromatography on SiO2 (Hexanes/EtOAc, 20/1) gave 4.15 g (100%) of 2-bromo-4-(1-methyl-propenyl)-thiophene as a liquid of isomeric mixture (Z/E isomer, 9/1). Z isomer; 1H NMR (400 MHz, CDCl3) δ 7.04 (d, J=1.7 Hz, 1H), 6.98 (d, J=1.7 Hz, 1H), 5.55 (m, 1H), 1.97 (quint, J=1.5 Hz, 3H), 1.72 (dq, J=7.0, 1.5 Hz, 3H). E isomer; 1H NMR (400 MHz, CDCl3) δ 7.17 (d, J=1.7 Hz, 1H), 6.94 (d, J=1.7 Hz, 1H), 5.90 (m, 1H), 1.94 (quint, J=1.1 Hz, 3H), 1.77 (d, J=6.9, 1.0 Hz, 3H).

1. temperaturecooled down to −78° C.
2. temperatureThe reaction mixture was slowly warmed to room temperature overnight
3. stirringwith stirring
4. washAfter dilution of the reaction mixture with EtOAc (200 mL), it was washed with water (70 mL×2) and brine (70 mL)
5. dry with materialdried (MgSO4)
6. concentrationconcentrated in vacuo

ORD record

ord-b81e58ac1c1f47ebb7c7630f7f2cb219

Source dataset

uspto-grants-2010_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07803837B2