ONE-POT SYNTHESIS OF PYRANO[2,3-c]PYRAZOLES USING LEMON PEEL POWDER AS A GREEN AND NATURAL CATALYST

Abstract

A simple one-pot four-component synthesis of pyrano[2,3-c]pyrazoles has been achieved by the condensation of aldehydes, malononitrile, ethyl acetoacetate and hydrazine hydrate using lemon peel powder as a natural catalyst in ethanol under reflux condition. The advantages of this reaction are less reaction time, high yield, easy availability of the catalyst and green nature of the protocol.

Recent Synthesis of Mono‐ & Bis‐Pyranopyrazole Derivatives

“…[167] Green natural product-derived lemon peel powder has also been used in ethanol under reflux conditions to yield pyranopyrazoles via four component reactions. [168] While, compounds (2) have also been synthesized by using polystyrene-supported-supported p-toluenesulfonic acid (PS-PTSA) and piperidine as catalysts, respectively, in mild reaction conditions to improve the yields. [169] Compound 2 exhibited promising anti-bacterial activities and cytotoxic activities (Scheme 12).…”

“…Interestingly, Some other catalysts such as nano‐eggshell/Ti(IV), [149] orange peel‐derived carbon‐bearing sulfonic acid (OPC‐SO 3 H), [150] Fe 3 O 4 @THAM‐SO 3 H [151] , MIL‐101(Cr)‐N(CH 2 PO 3 H 2 ) 2 , [152] Fe 3 O 4 @SiO 2 @(CH 2 ) 3 NH@CC@ imidazole@SO 3 H, [153] Fe 3 O 4 @Cu‐β‐CD, [154] NiFe 2 O 4 , [155] L‐tyrosine, [156] maltose, [157] molecular sieves, [158] morpholine triflate, [159] trichloroacetic acid, [44] thiamine hydrochloride, [160] Mn/ZrO 2 , [161] ZrO 2 NPs, [162] sodium benzoate, [50] silica‐supported tetramethylguanidine, [163] uncapped SnO 2 quantum dots (QDs), [164] zirconium magnetic nanocomposite, [165] borax, [166] and magnetized water [8] have also been used to improve the yield of product [167] . Green natural product‐derived lemon peel powder has also been used in ethanol under reflux conditions to yield pyranopyrazoles via four component reactions [168] …”

Green multicomponent synthesis of pyrano[2,3-c]pyrazole derivatives: current insights and future directions

“…Ghodke et al 78 developed a facile method for synthesizing pyrano[2,3- c ]pyrazoles via a component condensation reaction with lemon peel powder serving as a natural catalyst. In this process, malononitrile, aldehydes, ethyl acetoacetate, and hydrazine hydrate are reacted in ethanol under reflux conditions, with lemon peel powder ( Scheme 35 ).…”

One‐Pot Multicomponent Synthesis of Pyrano[2,3‐c]pyrazoles Facilitated by Novel Biocatalyst under Ambient Reaction Conditions

“…Highly substituted pyrano[2,3‐c]pyrazoles were recently reported utilising a variety of catalyst, viz. Piperazin, [14] PS‐DABCO, [15] Fe 3 O 4, [16] nano egg shell Ti(IV), [17] indeeca seed ash, [18] Fe 3 O 4 @NFC@CO(II), [19] Nanosized OPC‐SO 3 H powder, [20] Lemmon peel powder, [21] Bi 2 O 3 ‐ZrO 2 , [22] [Dsim]AlCl 4 , [23] BFA [24] …”