Aims: In this article, we have developed an eco-friendly one-pot multi-component reaction methodology
employed for the green synthesis of functionalized pyrazole derivatives viz cyclo-condensation of aromatic
aldehydes, ethyl acetoacetate and phenyl hydrazine and/or hydrazine hydrate in the presence of cetyltrimethylammoniumbromide
(CTAB) at 90°C temperature in an aqueous medium.
Materials and Methods: In the present protocol, we developed a green method for the synthesis of functionalized
pyrazole derivatives through one-pot, multi-component cyclo-condensation of aromatic aldehydes, phenyl hydrazine
or hydrazine hydrate and ethyl acetoacetate using cetyltrimethylammoniumbromide (CTAB) as a catalyst in water as
a solvent. Our methodology confers advantages such as short reaction time, atom economy, purification of the product
without using column chromatographic and hazardous solvent. The reaction is being catalyzed by cetyltrimethylammoniumbromide
(CTAB) and thus, products are formed under the green reaction conditions.
Results and Discussion: Initially, the reaction of benzaldehyde and phenylhydrazine with ethyl acetoacetate was carried
out in water at room temperature in the absence of the catalyst; no product was obtained after 24 h. When the reaction
was carried out using L-proline as a catalyst in ethanol at 70°C, the yield of the product was 20%.
Conclusion: This research not only provides a green and efficient method for the synthesis of sulfinic esters but
also shows new applications of electrochemistry in organic synthesis. We consider that this green and efficient
synthetic protocol used to prepare sulfinic esters will have good applications in the future. In conclusion, we have
developed successfully a green and efficient one-pot multi-component methodology for the synthesis of substituted
pyrazoles using CTAB as a catalyst in water as a solvent with excellent yields. Purifications of compounds
were achieved without the use of traditional chromatographic procedures. This methodology has advantages of
operational simplicity, clean reaction profiles and relatively broad scope, which make it more attractive for the
diversity oriented synthesis of these heterocyclic libraries. In this methodology, we suggest a further alternative
possibility for the formation of substituted pyrazoles. The compound 7h can be used as an anticancer drug in the