1,2-Dibromoethane → Methyl 5-bromo-3-(2,2,2-trifluoroacetamido)thiophene-2-carboxylate

Temperature

-78 °C

To a solution of N-(1-methylethyl)propan-2-amine (20 mL, 142 mmol) in THF (200 mL) was added 1.6 M n-butyl lithium in hexane (84.2 mL, 132 mmol) at 0° C. After stirring at this temperature for 15 min, the mixture was cooled to −78° C. Then, a solution of methyl 3-[(trifluoroacetyl)amino]thiophene-2-carboxylate (10.1 g, 40.0 mmol) in THF (50 mL) was added slowly. After additional stirring at −78° C. for 1 h, 1,2-dibromoethane (20.6 mL, 238 mmol) was added at once. The mixture was stirred at −78° C. for 30 min and at room temperature for 30 min. The mixture was poured into saturated aqueous NaHCO3 (600 mL) and extracted with EtOAc. The combined extracts were washed with brine, and then dried over Na2SO4. After removal of the solvent at reduced pressure, the residue was purified by column chromatography (Purif, silica gel, hexane to 10:90 hexane /EtOAc) to give the title compound (5.30 g, 41%) as a yellow solid:

1. stirringAfter additional stirring at −78° C. for 1 h
2. stirringThe mixture was stirred at −78° C. for 30 min and at room temperature for 30 min
3. extractionextracted with EtOAc
4. washThe combined extracts were washed with brine
5. dry with materialdried over Na2SO4
6. customAfter removal of the solvent at reduced pressure
7. customthe residue was purified by column chromatography (Purif, silica gel, hexane to 10:90 hexane /EtOAc)

ORD record

ord-e3ef6cf2b3084fe2bd27834a97f61ccf

Source dataset

uspto-grants-2014_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08691828B2