engleski

Synthesis of coumarin, rhodanine and thiazolidinedione derivatives in deep eutectic solvents via Knoevenagel condensation

Environmental pollution has led to the development of numerous methods in organic synthesis that are considered as green and environmental friendly. The application of deep eutectic solvents (DESs) in organic synthesis is considered a green method due to avoidance of organic solvents and toxic catalysts. Recently, DESs, due to their properties (thermal stability, low vapor pressure, biodegradability, nonflammability and component for their preparation are very cheap and easily available), are increasingly replacing conventional solvents. Many compounds are synthesized for the purposes of the pharmaceutical, food and many others industries. In this work three groups of compounds are synthesized, namely coumarins, rhodanines and thiazolidinediones. All compounds are synthesized in DESs via Knoevenagel condensation. Initially, model reaction was performed in 20 various DESs at 80 °C in order to find the best reaction media for each compound group. DESs are based on choline chloride (ChCl) as hydrogen bond acceptor and 20 other components in role of hydrogen bond donors. According to the highest yields obtained, it turned out that ChCl:urea, ChCl:acetamide and ChCl:N-methylurea are the best reaction medias for synthesis of coumarine, rhodanine and thiazolidinedione derivatives, respectively. Coumarine, rhodanine and thiazolidinedione derivatives (Scheme 1) were successfully synthesized and isolated. Coumarins are obtained in the yields from 6 to 98 %. The yields of synthesized rhodanine and thiazolidinedione derivatives were in the range 51 – 99 % and 21 – 90 %, respectively.

deep eutectic solvents ; synthesis ; coumarin ; rhodanine ; thiazolidinedione

nije evidentirano