2-Thiophenecarbonyl chloride → Tert-butyl 4-(thiophene-2-carbonyl)piperazine-1-carboxylate

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Reaction Steps

2-Thiophenecarbonylchloride (2.04 g, 1.49 mL) was added to a solution of tert-butyl-1-piperazinecarboxylate (2.5 g, 13.4 mmol) and DMAP (20 mg) in pyridine (15 mL) at 0° C. under N2 atmosphere and stirred at room temperature for overnight. The mixture was poured into ice water, the precipitate was filtered, washed several times with water, and dried to yield white solids (3.5 g, 88%). M.P. 76° C. 1H NMR (DMSO-d6): δ 1.42 (s, 12H), 3.40 (m, 4H), 3.61 (m, 4H), 7.12 (m, 1H), 7.43 (d, J=4.1 Hz, 1H), 7.77 (d, J=4.8 Hz, 1H). EIMS m/z 297 (M+1), 319 (M+23). Anal. (C14H20N2O3S) C, H, N.

Provenance & Evidence