Swift and Green Protocol for One-pot Synthesis of Pyrano[2,3- c]pyrazole-3-carboxylates With RuCaHAp as Catalyst

Author(s): Surya N. Maddila, Suresh Maddila, Werner E. van Zyl, Sreekantha B. Jonnalagadda.

Journal Name: Current Organic Chemistry

Volume 20 , Issue 20 , 2016

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Abstract:

An efficient, atom-economical, four-component one-pot reaction method was developed for pyrano[2,3-c]pyrazole-3-carboxylates using dimethylacetylenedicarboxylate, hydrazine hydrate, malononitrile and aromatic aldehydes, using a RuCaHAp catalyst. Ten new substituted pyrano[2,3-c]pyrazole-3-carboxylate derivatives (5a-k) were synthesized in good to excellent yields (88 to 97%), at room temperature with short reaction times ( 30 min) using the green solvent aqueous ethanol. RuCaHAp was prepared and characterized by various techniques including SEM, TEM, P-XRD and BET spectroscopy. The proposed heterogeneous catalyst that can be easily synthesized, is inexpensive and stable with good reusability (at least 6 times) showing marginal loss of activity. The suggested environmentally benign protocol offers high yields, clean reaction profiles, operational simplicity and no need for chromatographic separations.

Keywords: Green protocol, multicomponent reaction, heterogeneous catalyst, Ru hydroxyapatite, pyrano[2, 3-c]pyrazoles, recyclable.

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Article Details

VOLUME: 20
ISSUE: 20
Year: 2016
Page: [2125 - 2133]
Pages: 9
DOI: 10.2174/1385272820666160530104140
Price: $58

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