Hydrochloric Acid → 5-(4-Formylbenzylidene)-2,4-thiazolidinedione

Participants

Reaction Steps

To a mixture of terephthalaldehyde mono-(diethyl acetal) (3.96 mL, 20.0 mmol) and 2,4-thiazolidinedione (2.81 g, 24.0 mmol) in ethanol (40 mL) was added piperidine (2.0 mL, 20.0 mmol). The reaction mixture was heated to reflux for 4 h. After cooling on an ice-bath, hydrochloric acid (0.2 mol/L, 100 mL) was added and the precipitated products were collected by filtration. The cake was washed with water and dried. To a solution of this product (5.50 g) in tetrahydrofuran (180 mL) was added hydrochloric acid (1 mol/L, 18 mL) and the mixture was stirred at room temperature for 2 h. Water was added, and the precipitated products were collected by filtration to give 5-(4-formylbenzylidene)-2,4-thiazolidinedione (3.91 g, 94%).

Provenance & Evidence