4-Hydroxybenzaldehyde → 5-((4-Hydroxyphenyl)methylene)-2,4-thiazolidinedione

Participants

Reaction Steps

To a mixture of 4-hydroxybenzaldehyde (3.67 g, 30 mmol), 2,4-thiazolidinedione (3.51 g, 30 mmol) and benzoic acid (4.40 g, 36 mmol) in toluene (100 mL) was added piperidine (4.5 mL, 45 mmol) and the mixture was equipped with a Dean Stark apparatus and brought to a vigorous reflux. After 45 min the mixture was cooled in an ice bath and the supernatant was decanted. The bright yellow solid was made into a suspension by the addition of glacial acetic acid (100 mL) and filtered through a Buchner funnel to yield a pale yellow solid (6.00 g, 90%). 1H NMR: (400 MHz, DMSO-d6): δ 12.45 (bs, 1H), 10.30 (s, 1H), 7.70 (s, 1H), 7.45 (d, J=8.8 Hz, 2H), 6.91 (d, J=8.8 Hz, 2H).

Provenance & Evidence