Dimethylformamide → 3,4-Dimethylthiophene-2-carbaldehyde

Participants

Reaction Steps

To a solution of 3,4-dimethylthiophene trimer (3.7 g, 11 mmol) in 20 mL of a DMF: CHCl3 (1:1, v:v) solvent mixture, was added 20 mL of a solution of DMF and POCl3 (4:1, v:v). The DMF:POCl3 mixture was added cautiously, dropwise at 0° C. Following the addition, the reaction mixture was allowed to warm to ambient temperature and was stirred overnight. The reaction mixture was then poured into ice water and neutralized with 25% NaOH solution to pH˜8. The aqueous mixture was extracted with dichloromethane. Upon solvent removal the residue was subjected to purification by column chromatography using silica gel and a dichloromethane-petroleum ether (1:3) mixed solvent as the eluting solution to yield pure product 2-formyl-3,4-dimethylthiophen trimer 2.2 g (Yield: 55%) 1H NMR (CDCl3) δ 10.09 (1H, s, CHO), 7.00 (1H, s, aromatic H), 2.54 (3H, s, CH3), 2.23 (3H, s, CH3), 2.16 (3H, s, CH3), 2.13 (3H, s, CH3), 2.11 (6H, s, CH3), and the corresponding trimer dialdehyde 1.57 g (Yield: 37%) 1H NMR (CDCl3) δ 10.09 (2H, s, CHO), 2.54 (6H, s, CH3), 2.15 (12H, m, CH3).

Provenance & Evidence