Rapid Four-component Synthesis of Dihydropyrano[2,3-c]pyrazoles using Nano-egg Shell/Ti(IV) as a Highly Compatible Natural Based Catalyst

Abstract

Nano-egg shell/Ti(IV) (NEST) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole [DHPP] derivatives. The characterization of NEST was performed using Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Spectroscopy (EDX), and Thermo Gravimetric Analysis (TGA). DHPPs were synthesized in the presence of NEST via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are easy work-up, high yields of pure products without the use of any toxic organic solvents, mild condition and short reaction times.

Synthesis and characterization of novel biheterocyclic compounds from 3‐alkoxy‐1H‐pyrazole‐4‐carbaldehydes via multicomponent reactions

“…However, employing isonicotinic acid [52] in EtOH at room temperature gave 7 in 46% yield in only 10 min.…”

Recent Synthesis of Mono‐ & Bis‐Pyranopyrazole Derivatives

“…[1] The presence of catalyst [Fe 3 O 4 @CQD@Si(OEt) (CH 2 ) 3 NH@CC@Adenine@SO 3 H] + Cl À has produced (1) with 75-87 % [148] (Scheme 11). 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] Ltyrosine, [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.…”

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

“…[9][10][11][12][13] Highly substituted pyrano[2,3c]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] Remarkably, for the synthesis of pyranopyrazole via a fourcomponent reaction in organic solvents by using aldehyde, malononitrile, Hydrazine monohydrate and ethyl acetoacetate has been reported.…”