Aim and Objective: In this work, we tried to introduce a non-toxic and stable organic
compound named succinimide as a green and efficient organo-catalyst for the promotion of the
synthesis of arylidene malononitrile and tetrahydrobenzo[b]pyran derivatives. Using this method
led to a clean procedure to achieve these types of bioactive compounds without a specific
purification step. The rate and yield of the reactions were excellent, and also succinimide showed
acceptable reusability as the catalyst.
Materials and Methods: In a 25 mL round-bottom flask, [A: a mixture of aromatic aldehyde (1
mmol), malononitrile (1.1 mmol) and B: a mixture of aromatic aldehyde (1.0 mmol), malononitrile
(1.1 mmol)] and succinimide (0.2 mmol) in H2O/ EtOH [5 mL (1:1)] was stirred at 80 °C for an
appropriate time. After completion of the reaction, which was monitored by TLC [n-hexane-EtOAc
(7:3)], the mixture was cooled to room temperature, and the solid product was filtered, washed
several times with cold distilled water to obtain the corresponding pure product.
Results: After the optimization of the conditions and amount of the catalyst, a series of aromatic
aldehydes containing either-electron-donating or electron-withdrawing substituents were
successfully used for both of the reactions. The reactions rates and yields under the selected
conditions were excellent. The nature and electronic properties of the substituents had no obvious
effect on the rate and yield of the reaction. Meanwhile, the catalyst showed acceptable reusability
for these two reactions.
Conclusion: In this work, we have introduced Succinimide as a green and safe organo-catalyst for
the efficient synthesis arylidene malononitrile and tetrahydrobenzo[b]pyran derivatives. The results
showed that the catalyst had excellent efficiency in green aqueous media and also the reusability of
the catalyst was good.