Nanosilica Molybdic Acid as a Reusable Catalyst for Chemoselective Synthesis of Novel 4-Dihydropyrano[2,3-c]pyrazoles

Title:Nanosilica Molybdic Acid as a Reusable Catalyst for Chemoselective Synthesis of Novel 4-Dihydropyrano[2,3-c]pyrazoles

Volume: 14 Issue: 8

Author(s): Mahnaz Farahi*, Bahador Karami, Zahra Rajabi Behesht Abad and Sedigheh Akrami

Affiliation:

• Department of Chemistry, Yasouj University, Yasouj, Zip Code: 75918-74831 P.O. Box 353,Iran

Keywords: 4-Dihydropyrano[2, 3-c]pyrazoles, nanosilica molybdic acid, 3-methyl-1-phenyl-2-pyrazolin-5-one, aromatic aldehydes, ethyl cyanoacetate, green synthetic method.

Abstract: Background: A new convenient and practical green synthetic method for nanosilica molybdic acid (nano-SMA) catalyzed chemoselective synthesis of some new 4-dihydropyrano[2,3-c]pyrazoles through a one-pot reaction of 3-methyl-1-phenyl-2-pyrazolin-5-one, ethyl cyanoacetate and aryl aldehydes is described in this study.

Results: Nanosilica molybdic acid was synthesized and then characterized by X-ray fluorescence (XRF), powdered X-ray diffraction (XRD), IR spectroscopy and transmission electron microscopy (TEM). Due to the importance of novel catalyst applications, after preparation and characterization of the catalyst, we decided to use nano-SMA for the synthesis of 4-dihydropyrano[2,3-c]pyrazoles. After optimizing conditions, we found that this reaction was performed with 1 mol% of nano-SMA in refluxing EtOH. Then, the generality of the procedure was evaluated by examining various aryl aldehydes under optimized reaction conditions. The data obtained from elemental analysis, ¹H and ¹³C NMR spectra confirmed the proposed products.

Conclusion: Overall, we reported a green protocol for the chemoselective synthesis of 4-dihydropyrano [2,3-c]pyrazole derivatives. The advantages of this method are high yield of pure products, reusability of catalyst, short reaction times and a simple workup procedure, that make it an attractive and economical method for the synthesis of these useful heterocycles.

Cite this article as:

Farahi Mahnaz *, Karami Bahador , Abad Rajabi Behesht Zahra and Akrami Sedigheh , Nanosilica Molybdic Acid as a Reusable Catalyst for Chemoselective Synthesis of Novel 4-Dihydropyrano[2,3-c]pyrazoles, Letters in Organic Chemistry 2017; 14 (8) . https://dx.doi.org/10.2174/1570178614666170621094607

DOI https://dx.doi.org/10.2174/1570178614666170621094607	Print ISSN 1570-1786
Publisher Name Bentham Science Publisher	Online ISSN 1875-6255