Greener and facile aqueous synthesis of pyrazoles using Amberlyst-70 as a recyclable catalyst

Abstract

An environmentally benign, room temperature aqueous synthesis of pyrazoles by the condensation of hydrazines/ hydrazides with 1,3-diketones using Amberlyst-70 as a recyclable catalyst is described. The use of resinous, nontoxic, thermally stable and inexpensive Amberlyst-70 as a heterogeneous catalyst and simple reaction workup are the additional eco-friendly attributes of this synthetic protocol.

Experimental and Theoretical Tests on the Corrosion Protection of Mild Steel in Hydrochloric Acid Environment by the Use of Pyrazole Derivative

“…SEM and AFM analyses confirmed the existence of a protective film of the inhibitor on the MS surface [ 25 ]. Similarly, wear protection by pyrazoles has been prompted by a group of researchers who have developed new ways of using them since these derivatives as inhibitors have high chemical activity associated with high solubility in acids, with minimal environmental risk and toxicity, compared to other classes of organic compounds [ 26 , 27 ]. Previous studies have also examined the influence of temperature on pyrazoles in phosphoric media, as well as the effect of concentration.…”

Synthesis, Crystal Structure and Cu2+ Recognition of Novel Azobenzene Derivatives

“…3-Methyl-4-amino-5-mercapto-1,2,4-triazole, 10 3,5-dimethyl-1-Hpyrazole, 11 and (E)-4,4′-bicarboxyl azobenzene 12 were prepared according to literature procedures, other reactants and chemicals were purchased from Aladdin. Solvents were of analytical grade.…”

Synthetic strategies for 1,4,5/4,5‐substituted azoles: A perspective review

“…Synthetic methodology and applications for symmetrical 1,3,5-trisubstituted pyrazoles and 3,5-disubstituted isoxazoles are ubiquitous in literature and easy to execute. The most prevalent methods for 1,3,5-trisubstituted pyrazoles includes (i) treatment of an alkynyl aldehyde or ketone with hydrazine [21,22] (ii) reaction of 1,3-dicarbonyl compounds with hydrazine [23,24] (iii) reaction of alkenes or alkynes with diazoalkanes or nitrilimines [25,26]. Similarly, for 3,5-disubstituted isoxazoles, cycloaddition reactions of terminal acetylenes with nitric oxide [27][28][29], and reaction of hydroxylamine hydrochloride with α,β-chalcone dibromide [30,31] are common route for synthesis.…”