1-Piperidinecarboxaldehyde → 3-hexylthiophene-2-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To the solution of 2-bromo-3-hexylthiophene (13.5 g, 54.6 mmol) in anhydrous tetrahydrofuran (200 mL) in a dry ice/acetone bath at −78° C. was added n-butyl lithium (2.5 M in hexane, 24.0 mL, 60.1 mmol) dropwise under the protection of argon. The reaction solution was warmed to −40° C. and stirred for 60 min. The solution was cooled down to −78° C. again, and 1-formylpiperidine (7.41 g, 65.5 mmol) was added in one shot. Then, the solution was allowed to warm slowly up to room temperature and stirred overnight. The solution was then poured into ice water. The organic layer was separated and the aqueous layer was extracted twice with hexane (100 mL). The organic extracts were combined and washed three times with distilled water (50 mL), dried over anhydrous magnesium sulfate, and rotary evaporated to remove the solvent. The liquid residue was subjected to silica-gel column chromatography (EtOAc/hexane=1/10, Rf=0.4) to yield a clear liquid product (9.8 g, 92% yield). 1H NMR (400 MHz, acetone-d6) δ (ppm): 10.11 (s, 1H); 7.89 (d, 1H, J=5.2 Hz); 7.17 (d, 1H, J=5.2 Hz); 3.04 (t, 2H, J=7.8 Hz); 1.69 (m, 2H); 1.28-1.42 (m, 6 H); 0.87 (m, 3H).

Provenance & Evidence