Sulfuric Acid → Tert-butyl 5-bromothiophene-2-carboxylate

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).

1. stirringAfter stirring for 1 minute
2. stirringthe reaction was stirred at room temperature for 18 h
3. customThe reaction was quenched with saturated NaHCO3
4. customThe layers were separated
5. extractionthe aqueous layer was extracted with CH2Cl2
6. dry with materialthe combined organic layers were dried over MgSO4
7. concentrationThe organic solution was concentrated
8. customto give a clear oil which
9. customwas purified via medium pressure chromatography (3% EtOAc in hexanes)

ORD record

ord-ad92f0ef1cd84c899d778096ff0370f7

Source dataset

uspto-grants-2003_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06649657B2