Roona Poddar

Aqua mediated synthesis of 2-amino-6-benzothiazol-2-ylsulfanyl-chromenes and its in vitro study, explanation of the structure–activity relationships (SARs) as antibacterial agent

Multi-component reaction (MCR) involves coupling of p-bromophenol with 2-Benzothiazolethiol, malononitrile and substituted aldehydes in aqueous K(2)CO(3) as green base to synthesize 2-amino-6-benzothiazol-2-ylsulfanyl-chromenes. This multi-component reaction thus offers a higher yield and versatility in the preparation of densely functionalized oxygen heterocycles. The newly synthesized compounds were screened for their antibacterial activities against positive and gram negative pathogenic strains to bacteria. SAR analysis was performed to explore comprehensive structure-activity relationships and a statistically reliable model to explain their antibacterial activities.

C-Arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions

Summary CuO-nanoparticles were found to be an excellent heterogeneous catalyst for C-arylation of active methylene compounds using various aryl halides. The products were obtained in good to excellent yield. The catalyst can be recovered and reused for four cycles with almost no loss in activity.

N-acylation of ethanolamine using lipase: a chemoselective catalyst

Summary The N-acylation of ethanolamine (2) with various fatty acids 1a–d and esters of fatty acids 1e–h using Candida antarctica B lipase (Novozym® 435) are described and optimum conditions for selective N-acylation rather than O-acylation are also discussed. Microwave assisted solution phase, solid supported and conventional methods were investigated and results were compared. There is a synergy between the enzyme catalysis and microwave irradiation.

Lipase-catalyzed transformations using poly(ethylene glycol) as solvent

Abstract Candida antarctica lipase catalyzes a number of elementary reactions like alcoholysis, ammoniolysis and aminolysis in poly(ethylene glycol) (PEG) media. Reaction rates were comparable to or better than those observed in conventional organic reaction media and ionic liquids. It is envisaged that PEGs could have added benefits for performing biotransformations with highly polar substrates, which are sparingly soluble in common organic solvents.

Bis[(l)prolinate-N,O]Zn: A water-soluble and recycle catalyst for various organic transformations

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Laccase from Basidiomycetous Fungus–Catalyzed Synthesis of Substituted Benzopyranocoumarins via Domino Reaction

Abstract The present investigation provides a simple and convenient route to organic synthesis of substituted benzopyranocoumarin, which is important because it is a probable HIV protease inhibitor. The reaction of α,β-unsaturated derivatives of coumarins with catechol or 1,4-hydroquinones was catalyzed using laccase in an aqueous medium. Quinones, generated in situ by the oxidation of the corresponding catechol or 1,4-hydroquinones, underwent a domino reaction with chalcones to produce benzopyranocoumarins.