Oxalyl chloride → 1-(4-Dimethylaminopiperidin-1-yl)-2-thiophen-2-yl-ethane-1,2-dione

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Reaction Steps

2-Thiopheneglyoxylic acid (300 mg, 1.9 mmol) was dissolved in 10 mL of methylene chloride. A 2.0 M solution of oxalyl chloride in methylene chloride (1.1 mL, 2.1 mmol) was then added, followed by 10 μL of DMF. The resulting solution was stirred at room temperature for 1 hour, then a solution of dimethylpiperidin-4-ylamine (271 mg, 2.1 mmol) and DIPEA (1.0 mL, 5.8 mmol) in 2 mL of methylene chloride was added. 4-Dimethylaminopyridine (12 mg, 96 μmol) was then added and the resulting mixture was stirred at room temperature for 2 hours. The mixture was then extracted with a saturated sodium bicarbonate solution, and the organic layer was dried over Na2SO4 and concentrated to yield the crude intermediate (4a) (498 mg), which was used in the next step without further purification.

Provenance & Evidence