반응 #567510

반응 방정식

tert-butanol

H2SO4

MgSO4

5-bromo-thiophene-2-carboxylic acid

→

title compound

수율 94.4%

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

수율 94.4%

용매

CH2Cl2

반응 조건

후처리

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

실험 절차

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).

출처