One Pot Synthesis of Pyranopyrazole Using Sodium Lactate as an Efficient Catalyst

Abstract

An efficient one pot synthesis of pyranopyrazoles has been achieved by the four-component condensation of hydrazine hydrate, ethyl acetoacetate, aldehydes and malononitrile using sodium lactate as a catalyst in aqueous ethanolic medium under reflux condition. The method is simple and green to afford pyranopyrazoles in a short time. It provides a new base catalyst that readily gives product from moderate to excellent yields.

Green Synthesis of Pyrazoles: Recent Developments in Aqueous Methods

“…In 2019, Thore and co-workers used the reaction of arylaldehydes and malononitriles with 3-methyl-1,4-dihydro-5 H -pyrazol-5-ones or ethyl acetoacetate using triethanolamine or sodium lactate catalyst, respectively, to give dihydropyrano[2,3- c ]pyrazoles 12 (Scheme 29 ). 74 Khandebharad and co-workers reported a similar reaction using the recyclable organocatalyst sodium gluconate (Scheme 30 ). 75…”

“…Jayant P Sonar et al worked with triethanolamine as well as sodium lactate catalyst74 (Scheme 29) and Khandebharad et al with the recyclable organocatalyst sodium gluconate (Scheme 30) 75 . 29 Triethanolamine and sodium lactate catalysed syntheses Scheme 30 Use of sodium gluconate as recyclable organocatalyst in pyrazoles synthesis Isoniazid has been used with aldehydes, EAA and malononitrile to obtain some new pyrazoles by employing the biocatalyst 2aminoethanesulfonic acid (taurine).…”

Recent Synthesis of Mono‐ & Bis‐Pyranopyrazole Derivatives

“…Sajjadi et al (2023), for instance, reported on the synthesis of dihydropyrano[2,3c]pyrazoles via Knoevenagel-Michael multiple reactions by using green catalyst Fe 3 O 4 @gC 3 N 4 for the reaction of aldehydes, phenylhydrazine, ethyl acetoacetate and malononitrile under 1 h reflux to achieve 97 % yield of product (Route 1). [51] This reaction has also been reported by using numerous catalysts such as 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate ([DBU][Ac], [59] HMS/PrÀ Rh-Zr, [60] H 3 PO 4 /Al 2 O 3 , P 2 O 5 /SiO 2 , starch sulfuric acid, cellulose sulfuric acid, [61] thiourea dioxide (TUD), [62] PVCÀ EDAÀ CeIII, [63] citrus limon (lemon juice), [64] agave leaf ash extract, [65] piperidine, [66] sodium lactate, [67] NiWO 4 , [68] PBCMOamine, [69] CaO nanoparticles, [70] Fe 3 O 4 @chitosan-tannic acid bionanocomposite, [71] FSiPSS nano-catalyst, [72] nano ZrO 2 , [73] lactic acid : urea : NH 4 Cl, [74] H 4 [SiW 12 O 40 ], [75] NiFe 2 O 4 @SiO 2 À H 3 PW 12 O 40 (NFSÀ PWA), [76] Fe 3 O 4 @SiO 2 @CoSB, [77] PAN@melamine/Fe 3 O 4 nanocomposite, [78] isonicotinic acid, [79] nano-[Fe-PSMP]Cl 2 , [80] Fe 3 O 4 /MIP-202-H 4 WO 5 , [81] Zn(L-proline) 2 , [82] baker's yeast, [83] solar radiation, [84] Cu-DABP@Fe 3 O 4 /MCM-41, [85] Fe 3 O 4 @NFC@Co(II), [86] PdO/Al-SBA-15, [87] (MnCoFe 2 O 4 @Niacin-SO 3 H) + Cl À , [88] Zn-CA-MOFs [89] and Na 2 CaP 2 O 7 . [90] In 2022, Nguyen and coworkers reported different routes to the synthesis of pyrano[2,3-c]pyrazole derivatives, which involved a four-component reaction of benzyl alcohols, phenylhydrazine, ethyl acetoacetate and malononitrile with the aid of sulfonated amorphous carbon and eosin Y as c...…”

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

“…Impressively, the catalyst retained its efficacy and could be reused for up to three cycles. J. P. Sonar et al 74 employed sodium lactate as a catalyst within an aqueous ethanolic environment under reux conditions to synthesize pyranopyrazoles. This process involved the combination of hydrazine hydrate, ethyl acetoacetate, malononitrile, and various aldehydes (Scheme 30).…”