Methanol → Methyl 4-bromo-5-ethylthiophene-2-carboxylate
Reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([C:9]([OH:11])=[O:10])[S:5][C:6]=1[CH2:7][CH3:8].S(=O)(=O)(O)O.O.[CH3:18]O>>[Br:1][C:2]1[CH:3]=[C:4]([C:9]([O:11][CH3:18])=[O:10])[S:5][C:6]=1[CH2:7][CH3:8]Participants
5
Conditions
- Temperature
- 50 °C
Procedure
To a solution of 4-bromo-5-ethyl-2-thiophenecarboxylic acid (1 g, 4.25 mmol) in methanol (21.27 ml) was added sulfuric acid (0.23 mL, 4.25 mmol). The resulting solution was stirred at 50° C. for 48 h. H2O (50 mL) was added and the reaction was cooled to 0° C. in an ice-bath. The pH was adjusted to 12 and the aqueous phase was washed several times with DCM. The combined organic fractions were dried over Na2SO4, concentrated and used directly without further purification providing methyl 4-bromo-5-ethyl-2-thiophenecarboxylate (1.060 g, 4.25 mmol, 100% yield): LCMS (ES) m/e 248, 250 (M, M+2)+.
Workup
- temperaturethe reaction was cooled to 0° C. in an ice-bath
- washthe aqueous phase was washed several times with DCM
- dry with materialThe combined organic fractions were dried over Na2SO4
- concentrationconcentrated
- customused directly without further purification
Sources & evidence
- ORD record
- ord-202e86713bbd4131bfc1b0da5ac3b8c8
- Source dataset
- uspto-grants-2015_02
- Patent number
- US08946278B2
Reaction notes
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