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

HRID 632549Notes

Reaction equation

[CH3:1][C:2]([CH3:14])([CH3:13])[C:3]#[C:4][C:5]1[S:9][C:8]([C:10]([OH:12])=[O:11])=[CH:7][CH:6]=1.[Li]CCCC.[I:20]I>C1COCC1>[CH3:1][C:2]([CH3:14])([CH3:13])[C:3]#[C:4][C:5]1[S:9][C:8]([C:10]([OH:12])=[O:11])=[C:7]([I:20])[CH:6]=1

Participants

Conditions

Temperature: -78 °C

Procedure

To a solution of 5-(3,3-Dimethyl-but-1-ynyl)-thiophene-2-carboxylic acid (6.2 g, 30 mmol; see U.S. Pat. No. 5,861,421) in THF (100 mL) was added a solution of nBuLi (2.0 M 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 1 N 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 1 M 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.

Workup

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

Sources & evidence

ORD record: ord-4020f2950c8c4ec9946046b4d9f67540
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09321753B2

Reaction notes

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