An efficient synthesis of 5-arylidene-2,4-thiazolidinediones and 5-benzylidene rhodanines by the Knoevenagel condensation of 2,4-thiazolidinedione or rhodanine with aromatic aldehydes was studied. It proceeded smoothly in the presence of tetrabutylammonium hydroxide/H 2 O-EtOH to afford the corresponding products in high yields at 50°C. Also, a series of dihydrothiophene derivatives were synthesized via the four-component reaction of aldehyde, malonitrile, ...
![4-Thiazolidinone,5-[(2,4-dichlorophenyl)methylene]-2-thioxo- Structure](https://image.chemsrc.com/caspic/194/26738-34-1.png)