Suresh Maddila

Mn doped ZrO2 as a green, efficient and reusable heterogeneous catalyst for the multicomponent synthesis of pyrano[2,3-d]-pyrimidine derivatives

A simple and an efficient method has been developed for the one-pot multicomponent synthesis of pyrano[2,3-d]-pyrimidine derivatives. This was achieved through the condensation reaction between dimethylbarbituric acid, aromatic aldehyde and malononitrile in the presence of a Mn/ZrO2 heterogeneous catalyst with ethanol/water mixture as solvent for only 1 hour. Further advantages of this synthesis methodology include excellent yields, mild reaction conditions, atom economy, environmentally friendliness, reusable catalyst and no need for chromatographic separations.

Eco-efficient ultrasonic responsive synthesis of pyrimidines/pyridines.

Using ultrasound irradiation, two simple one-pot multicomponent methods are described for syntheses of highly functionalized pyrimidine/pyridine derivatives in excellent yields in the presence of NaOH at room temperature. While one route involved aromatic aldehyde, thiourea and acetoacetanilide, the other employed aromatic aldehyde, malononitrile and benzyl mercaptane or EtOH. These approaches afford several advantages over former and contemporary reaction methodologies in terms of operational simplicity, simple work-up procedure, higher yield, short reaction time and environment friendly protocols.

Ceria–Vanadia/Silica‐Catalyzed Cascade for C−C and C−O Bond Activation: Green One‐Pot Synthesis of 2‐Amino‐3‐cyano‐4H‐pyrans

Abstract We designed a ceria–vanadia/silica (Ce–V/SiO2) heterogeneous catalyst and used it for the green and efficient synthesis of 2‐amino‐3‐cyano‐4H‐pyran derivatives. The green reaction was a multicomponent one‐pot condensation of 5,5‐dimethylcyclohexane‐1,3‐dione, aromatic aldehyde, and malononitrile in an eco‐compatible solvent (ethanol). The catalyst was synthesized and fully characterized by powder X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analysis. The reported procedure offers a number of advantages including decreased reaction times, mild conditions, high yields, operational simplicity, and environmentally benign and simple work‐up procedures. Furthermore, the catalyst is economical, fully recyclable, and reusable for over five runs while preserving its high activity. The synthesized 2‐amino‐3‐cyano‐4H‐pyran products can later be used for pharmaceutical purposes.

Synthesis and characterization of Pd(II) dispersed over diamine functionalized graphene oxide and its scope as a catalyst for selective oxidation

A protocol for synthesis of active palladium(II) over diamine functionalized graphene oxide (Pd(II)-AAPTMS@GO) is described. The catalyst gave excellent conversion (96%) of benzyl alcohol with 99% selectivity towards benzaldehyde. The active catalytic material was fully characterized by BET surface area analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the FT-IR results, the organic amine was successfully grafted over the graphene surface. The palladium distribution on the graphene oxide surface was confirmed by TEM. The catalytic activity remained unaltered in the first five cycles, but the efficiency of conversion and yield dropped to 89% in the 6th cycle.

Synthesis and Biological Activity of Ethyl 2-(substituted benzylthio)-4-(3′-(ethoxycarbonyl)biphenyl-4-yl)-6-methyl-1,4-dihydropyrimidine-5-carboxylate Derivatives

In the present study, a new series of ethyl 2‐(substituted benzylthio)‐4‐(3′‐(ethoxycarbonyl)‐biphenyl‐4‐yl)‐6‐methyl‐1,4‐dihydropyrimidine‐5‐carboxylate derivatives was synthesized. The newly synthesized compounds were characterized by 1H‐NMR, mass and C, H, N analyses. All newly synthesized compounds were screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes and Klebsiella pneumoniae) and antifungal (Aspergillus flavus, Aspergillus fumigatus, Candida albicans, Penicillium marneffei and Trichophyton mentagrophytes) activity. The results revealed that all synthesized compounds have a significant biological activity against the tested microorganisms. Compounds 8a, 8b, 8c, 8e, 8f, 8i, and 8j exhibited good antimicrobial activity.

Novel 2-(1-(substitutedbenzyl)-1H-tetrazol-5-yl)-3-phenylacrylonitrile derivatives: synthesis, in vitro antitumor activity and computational studies

This work describes the two-step synthesis of new series of 2-(1-(substitutedbenzyl)-1H-tetrazol-5-yl)-3-phenylacrylonitrile derivatives (6a–k) starting from substituted benzyl halides (5a–k) and 3-phenyl-2-(1H-tetrazol-5-yl)acrylonitrile (4). Initially, compound 4 was synthesized using benzaldehyde, malononitrile and sodium azide. All the synthesized compounds were obtained in good yields and were characterized using 1H NMR, 13C NMR, FTIR and HRMS spectral data. The new compounds (6a–k) were evaluated for their potential in vitro antitumor activity against four human cancer cell lines (MCF-7, CaCO2, HeLa and SkBr3) by MTT assay. The most potent compounds 6b, 6h and 6j show good activity (IC50 values) relative to 5-fluorouracil, with potential to be antitumor agents. Compounds 6a, 6c, 6g, 6f and 6k showed moderate activity. The best performing three compounds (6b, 6h and 6j) were evaluated for in silico analysis on the PharmMapper web server, and the human mitogen-activated protein kinase 1 (MEK-1) enzyme was recognized as the main target protein. MEK-1 inhibition by these compounds was further confirmed by the docking study to corroborate the target.Graphical Abstract

Mg–V/CO3 hydrotalcite: an efficient and reusable catalyst for one-pot synthesis of multisubstituted pyridines

Mg–V/CO3 hydrotalicite (Mg–V/CO3 HTlc) as an effective heterogeneous catalyst was synthesized by a simple technique. The catalyst was identified by PXRD, TEM, SEM and BET surface area analysis. The catalyst is fully recyclable and reusable for several runs preserving its high activity. The catalytic activity of Mg–V/CO3 HTlc is described by synthesis of a series of pyridines in good to excellent yields via a facile one-pot multicomponent reaction with a shorter reaction time.Graphical Abstract

Ce–Zr/SiO2: a versatile reusable heterogeneous catalyst for three-component synthesis and solvent free oxidation of benzyl alcohol

Ce–Zr loaded on SiO2 as catalyst provides an extremely efficient method to synthesize pyranoquinolines. This catalyst is found to be superb for the three-component synthesis of target compounds and for the solvent-free liquid-phase oxidation of benzyl alcohols. The catalyst is fully recoverable and reusable with no loss of catalytic activity even after multiple cycles.

Multicomponent synthesis of pyridines via diamine functionalized mesoporous ZrO2 domino intramolecular tandem Michael type addition

A new and straightforward synthetic method was developed for the facile synthesis of heterocycle-fused pyridine derivatives in aqueous media from Knoevenagel condensation between an aromatic aldehyde and an active methylene compound. This was followed by Michael type addition of a ketone to the activated double bond of the arylidene via intramolecular cyclization in the presence of diamine functionalized [N-(2 amino ethyl)-3-amino propyl trimethoxy silane (AAPTMS)] mesoporous ZrO2 (AAPTMS/m-ZrO2) to synthesize fused pyridines in high yield. This one-pot conversion, which involves multiple steps and requires no toxic/organic solvents, produced new C–C and C–heteroatom bonds with all reactants efficiently utilized.

Catalyst-free, one-pot, four-component green synthesis of functionalized 1-(2-fluorophenyl)-1,4-dihydropyridines under ultrasound irradiation

An environmentally friendly catalyst-free synthesis protocol for functionalized 1,4-dihydropyridine derivatives involving four components under ultrasonic irradiation in aqueous ethanol is reported. Eleven new compounds are synthesized using multi-component one-pot reaction between dimethylacetylenedicarboxylate, 2-fluoroaniline, malononitrile and various substituted aldehydes. The establishment of multiple carbon–carbon bonds occurs in the absence of any hazardous organic solvents or catalysts. The target compounds were obtained in excellent yields (89–96%). All the new compounds were identified and validated by IR, 1H NMR, 13C NMR, 19F NMR, 15N NMR and HRMS spectral data. The new procedure has noteworthy advantages including safety, short reaction times, environmentally benign mild conditions and high yields.