Reacción #567510

Ecuación de reacción

tert-butanol

H2SO4

MgSO4

5-bromo-thiophene-2-carboxylic acid

→

title compound

Rendimiento 94.4%

5-Bromo-thiophene-2-carboxylic acid tert-butyl ester

Rendimiento 94.4%

Disolventes

CH2Cl2

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGAfter stirring for 1 minute
2. 2
   workup.STIRRINGthe reaction was stirred at room temperature for 18 h
3. 3
   OtroThe reaction was quenched with saturated NaHCO3
4. 4
   OtroThe layers were separated
5. 5
   Extracciónthe aqueous layer was extracted with CH2Cl2
6. 6
   Secadothe combined organic layers were dried over MgSO4
7. 7
   ConcentraciónThe organic solution was concentrated
8. 8
   Otroto give a clear oil which
9. 9
   Otrowas purified via medium pressure chromatography (3% EtOAc in hexanes)

Procedimiento

To a mixture of anhydrous MgSO4 (11.60 g, 96.4 mmol) in 100 mL CH2Cl2 was added concentrated H2SO4 (1.45 mL, 24.1 mmol) and the mixture was stirred for 15 minutes followed by addition of 5-bromo-thiophene-2-carboxylic acid (5.0 g, 24.1 mmol). After stirring for 1 minute, tert-butanol (11.6 g, 20 mmol) was added and the reaction was stirred at room temperature for 18 h. The reaction was quenched with saturated NaHCO3. The layers were separated, the aqueous layer was extracted with CH2Cl2, and the combined organic layers were dried over MgSO4. The organic solution was concentrated to give a clear oil which was purified via medium pressure chromatography (3% EtOAc in hexanes) to afford the title compound (4.97 g). 1H NMR (400 MHz, CDC13) δ 7.45 (d, 1H), 7.02 (d, 1H), 1.54 (s, 9H).

Fuente