Nickel Boride–Mediated Cleavage of 1,3-Dithiolanes: A Convenient Approach to Reductive Desulfurization

1,3-Dithiolanes are rapidly cleaved by nickel boride, generating corresponding hydrocarbons in excellent yields. The hydrogenolysis is rapid at room temperature and does not require protection from the atmosphere. Mild reaction conditions, simple workup, and good yields of pure products are some of the major advantages of the procedure.     

Acetic acid catalysed solvent-free synthesis of spiro-isoxazolo[5,4-b]pyridines/quinolines by mechano-chemical grinding

A simple and efficient three-component procedure has been developed for the synthesis of a series of spiro-isoxazolo[5,4-b]pyridines/quinolines by one-pot condensation of isatins, 3-methylisoxazol-5-amine and enolizable cyclic carbonyl compounds. The protocol has been accomplished under solvent-free conditions by grinding the components at room temperature in presence of catalytic CH₃COOH. The described process offers environmentally benign reaction conditions for the synthesis of pharmacologically important spirooxindole fused heterocycles with the advantages ofoperational simplicity, short reaction time and good to excellent yields of isolated pure product.     

Structure-aided drug development of potential neuraminidase inhibitors against pandemic H1N1 exploring alternate binding mechanism

Molecular Diversity - The rate of mutability of pathogenic H1N1 influenza virus is a threat. The emergence of drug resistance to the current competitive inhibitors of neuraminidase, such as...     

pTSA-catalyzed one-pot synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in ionic liquid and neat conditions

Multi-component condensation of β-naphthol, aromatic aldehydes, and cyclic 1,3-dicarbonyl compounds catalyzed by p-toluenesulfonic acid has been accomplished for the synthesis of a series of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in ionic liquid([bmim]BF₄) and in solvent-free media. High yields, ease of recovery, and reusable reaction medium (ionic liquid) with consistent activity makes this protocol efficient and environmentally benign.     

Efficient one-pot syntheses of 2H-indazolo[2,1-b] phthalazine-triones by catalytic H2SO4 in water-ethanol or ionic liquid

Sulfuric acid-catalyzed, three-component, one-pot condensation of phthalhydrazide, aromatic aldehydes and 1,3-dicarbonyl compounds has been reported for the synthesis of a series of 2H-indazolo[2,1-b] phthalazine-triones in water-ethanol or in ionic liquid. The protocol proves to be efficient and environmentally benign in terms of high yields, low reaction times, ease of recovery, and reusability of reaction medium (ionic liquid).     

Green Approaches for the Synthesis of 12-Aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in Aqueous Media and Under Microwave Irradiation in Solventless Conditions

Convenient and environmentally benign procedures have been reported for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one derivatives by multi component condensation reactions of aromatic aldehydes with β-naphthol and cyclic 1,3-dicarbonyl compounds, namely, dimedone and cyclohexane-1,3-dione. The three-component condensation has been successfully achieved in one pot by refluxing the components in water and is efficiently catalyzed by sulfuric acid. The condensation has also been achieved by irradiating the components in the presence of a catalytic amount of para-toluene sulfonic acid under neat conditions with microwaves. The green methodologies defined herein avoid the severe conditions posed by the older existing methods and prove to be efficient in terms of good yields, operational simplicity, easy workup, and short reaction time.     

Efficient and Green Approaches for the Synthesis of 4H-Benzo[g]chromenes in Water,Under Neat Conditions,and Using Task-Specific Ionic Liquid

Facile and convenient procedures have been described for the synthesis of 4H-benzo[g]chromenes by one-pot condensation of aromatic aldehydes, malononitrile/ethyl cyanoacetate, and 2-hydroxy-1,4-naphthoquinone. The reaction has been accomplished using catalytic cetyltrimethylammonium bromide (CTAB) in water under reflux or under neat conditions at 110 °C. A task-specific ionic liquid, 1-butyl-3-methyl imidazolium hydroxide ([bmim]OH), has also been found to be an effective catalyst for this transformation. The protocols prove to be environmentally benign and offer advantages of good yields, short reaction times, and simple workup procedures. The ionic liquid could be recycled and reused for up to four runs without appreciable loss in the activity.     

Lanthanum Triflate–Catalyzed Rapid Oxidation of Secondary Alcohols Using Hydrogen Peroxide Urea Adduct (UHP) in Ionic Liquid

A convenient and efficient protocol for the oxidation of secondary hydroxyl group to ketone using hydrogen peroxide–urea adduct and catalytic (CF₃SO₃)₃La in ionic liquid has been developed. A number of 1,2-diols, α-hydroxyketones, and other aromatic and aliphatic secondary alcohols have been successfully oxidized to the corresponding ketones using this protocol in good yields and short reaction times.

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