Iodine → 5-(3,3-Dimethylbut-1-ynyl)-3-iodothiophene-2-carboxylic acid

Temperature

-78 °C

To a solution of 5-(3,3-dimethyl-but-1-ynyl)-thiophene-2-carboxylic acid (6.2 g, 30 mmol; see patent application U.S. Pat. No. 5,861,421) in THF (100 mL) was added a solution of nBuLi (2.0M in pentane, 33 mL, 66 mmol) via an addition funnel at −78° C. After addition, the reaction was stirred at −78° C. for 1 h. A solution of I2 (7.7 g, 30 mmol) in THF (100 mL) was added slowly (ca. 15 min) to the flask. After a further 10 mins, the reaction was quenched with 1N HCl (50 mL) and warmed to room temperature. The volatiles were removed in vacuo and the residue was dissolved in ether (500 mL). The organic solution was washed with 1M Na2S2O3 (100 mL×2), brine (100 mL) and dried over Na2SO4. After concentrated in vacuo, the residue was purified by silica gel chromatography (EtOAc/hexanes) to give 5-(3,3-dimethyl-but-1-ynyl)-3-iodo-thiophene-2-carboxylic acid (5.9 g, 65%) as a white solid.

1. additionAfter addition
2. waitAfter a further 10 mins
3. customthe reaction was quenched with 1N HCl (50 mL)
4. temperaturewarmed to room temperature
5. customThe volatiles were removed in vacuo
6. dissolutionthe residue was dissolved in ether (500 mL)
7. washThe organic solution was washed with 1M Na2S2O3 (100 mL×2), brine (100 mL)
8. dry with materialdried over Na2SO4
9. concentrationAfter concentrated in vacuo
10. customthe residue was purified by silica gel chromatography (EtOAc/hexanes)

ORD record

ord-50536b8b89a24686aab29eae59d87ed4

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08513298B2