1-Bromo-2-methylpropane → 5-(2-Methylpropyl)thiophene-2-carboxylic acid

Temperature

-78 °C

To a solution of 2-thiophene-carboxylic acid (4.16 g, 32.1 mmol) in THF (200 mL) tert. butyllithium (49 mL, 1.7 M solution in pentane, 83.6 mmol) is slowly added at −78° C. The mixture is stirred at −78° C. for 30 min before isobutylbromide (22.7 g, 160.7 mmol) is carefully added. The mixture is stirred at −78° C. for 5 h, then at rt for 16 h. The reaction is quenched by the addition of water (400 mL). The mixture is acidified and extracted with EA. The org. extract is dried over MgSO4, filtered and evaporated. The crude product is purified by MPLC on reverse phase silica gel to give the title compound (1.67 g) as a brownish oil; LC-MS: tR=0.91 min, 1H NMR (CDCl3): δ 0.96 (d, J=6.7 Hz, 6H), 1.94 (hept, J=6.7 Hz, 1H), 2.72 (d, J=7.0 Hz, 2H), 6.80 (d, J=3.8 Hz, 1H), 7.73 (d, J=3.8 Hz, 1H).

1. additionis carefully added
2. waitat rt for 16 h
3. customThe reaction is quenched by the addition of water (400 mL)
4. extractionextracted with EA
5. extractionextract
6. dry with materialis dried over MgSO4
7. filtrationfiltered
8. customevaporated
9. customThe crude product is purified by MPLC on reverse phase silica gel

ORD record

ord-5cd44082c49845b890aa93d09c82fe13

Source dataset

uspto-grants-2012_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08133910B2