Background: Thiazolidine compounds are known to show interesting pharmacological
activity. In particular, they are used as antiseizure, fungicidal, anti-bacterial, antitubercular, antiinflammatory,
antiamoebic, anti-diabetic and local anesthetic agents. Some of these compounds have
also shown antiparkinsonism, antioxidant, anticonvulsant, hypoglycemic and non-narcotic analgesic
activities. On the other hand, pyrazoles have shown antibacterial, antitumor, antiviral, antifungal,
anti-tubercular, antiparasitic, anesthetic, anti-diabetic, anti-inflammatory, analgesic and insecticidal
activities. In order to improve the pharmacological effects of thiazolidine-4-ones, new pyrazole
derivatives have been synthesized.
Material and Methods: A mixture of pyrazolcarbaldehydes, anilines, thioglycolic acid and
DSDABCOC was stirred at room temperature for the required reaction times. The progress of the
reaction was monitored by TLC (EtOAc: petroleum ether 1:3). After completion of the reaction as
indicated by TLC, the ionic liquid was separated by extraction with 2×15 mL of water. The solid
residue was separated by column chromatography. The product was recrystallized from EtOH. The
pure products were collected in 82-92% yields.
Results: In continuation of our ongoing studies to synthesize heterocyclic and pharmaceutical
compounds under mild and practical protocols, we wish to report herein our experimental results on
the ultrasound promoted synthesis of 2-pyrazolo-3-phenyl-1,3-thiazolidine-4-ones using various
synthesized pyrazolecarbaldehydes, anilines and thioglycolic acid at room temperature. The results
illustrated that ionic liquid DSDABCOC certainly improved the yield of the products and reduced
the reaction time.
Conclusion: In conclusion, we have developed an efficient and simple protocol for the synthesis of
novel pyrazolo-1,3-thiazolidine-4-ones using DSDABCOC as an ionic liquid. The easy workup
together with the use of inexpensive, reusable and eco-friendly ionic liquid is the notable feature of
this novel procedure. To the best of our knowledge, this is the first report of the synthesis of a new
library of 1,3-thiazolidine-4-ones bearing a pyrazolyl moiety that enhances the biological activity
under solvent-free conditions.