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-ce146f95213140ed9ede95613739863b
- Source dataset
- uspto-grants-2012_09
- Patent number
- US08273782B2
Reaction notes
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