GO-CuS catalyzed ortho-aminomethylation of phenol derivatives with N,N-dimethylbenzylamines: site-selective oxidative CDC.

Copper chalcogenide nanoparticles (CuS) supported on graphene oxide (GO) have been synthesized for the first time from CuS, and used as highly efficient heterogeneous catalysts for oxidative ortho-selective C-H aminomethylation of phenols with N,N-dimethylbenzylamines. The NPs (30-80 nm) have been characterized by HRTEM, SEM-EDX, PXRD, FTIR, Raman, ICP-AES and XPS analyses. The NP catalyzed sp-sp cross dehydrogenative coupling (CDC) features a broad substrate scope, excellent functional group tolerance, high yields, use of an inexpensive and reusable copper catalyst, mild conditions, and no need for pre-functionalization of substrates.

Regioselective Synthesis of N-Alkylated-1,2,3 Triazoles and N-Alkylated Benzotriazoles: CuS as a Recyclable Nanocatalyst for Oxidative Amination of N, N-Dimethylbenzylamines.

Copper chalcogenide nanoparticles (CuS) synthesized for the first time from a single-source precursor, CuSPh, act as highly efficient and reusable heterogeneous catalyst for regioselective amination of N, N-dimethylbenzylamines with various azoles. The reaction involves N-H/C-H cross-dehydrogenative coupling (CDC) and demonstrates wide functional group tolerance. It provides highly selective access to N-alkylated benzotriazoles, N-alkylated 1,2,3-triazoles and 4-phenyl-1,2,3-triazoles, and N-alkylated carbazoles in 70-89% yields under solvent-free conditions.

N-Mannich Bases of Aromatic Heterocyclic Amides: Synthesis via Copper-Catalyzed Aerobic Cross-Dehydrogenative Coupling under Ambient Conditions.

An efficient and facile method to synthesize N-Mannich bases has been developed using an inexpensive copper(I) bromide/air catalyst system at ambient temperature. A cross-dehydrogenative coupling of N,N-dimethylarylamines occurs efficiently with aromatic heterocyclic amides (oxindoles, isatins), cyclic amides (lactams), simple amides (benzamide), as well as imides (succinimide, phthalimide) to furnish the corresponding amidated/imidated derivatives in good to excellent yields. Preliminary mechanistic and isotope-labeling studies suggest the reaction follows a radical pathway and involves an iminium ion intermediate.

Copper-Catalyzed anti-Markovnikov Hydroindolation of Terminal Alkynes: Regioselective Synthesis of Bis(indolyl)alkanes.

An efficient copper-catalyzed intermolecular hydroindolation reaction of terminal aryl alkynes to expeditiously synthesize bis(indolyl)alkanes in moderate to high yields is described. The double nucleophilic addition of two molecules of indole to one molecule of alkyne occurs in a tandem manner through an anti-Markovnikov pathway. Various arenes and alkynes allow for this transformation.

I2 mediated synthesis of 5-substituted-3-methyl/benzyl-1,3,4-oxadiazol-2(3H)-ones via sequential condensation/oxidative cyclization and rearrangement.

A simple and efficient iodine-assisted protocol for the synthesis of 5-substituted-3-methyl/benzyl-1,3,4-oxadiazol-2(3H)-ones has been developed. The reaction involves a sequential condensation followed by tandem oxidative cyclization and rearrangement of readily available methyl/benzyl carbazates and aldehydes as starting substrates. The presence of iodine and base promotes intramolecular C-O bond formation, followed by Chapman-like rearrangement at 90 °C of the methyl/benzyl group in the hydrazone intermediate formed during the condensation step.

Design, synthesis and antimicrobial evaluation of novel 1,3-oxazolidin-2- one derivatives.

A series of novel derivatives of 1,3-oxazolidin-2-one 12a-12n has been synthesized starting from 4-nitro-(L)- phenylalanine by involving five-step reaction sequence. All the compounds were screened for their in vitro antibacterial activity against four pathogenic bacterial strains namely, Staphylococcus aureus, Bacillus subtilis (Gram-positive), Escherichia coli, Pseudomonas aeruginosa (Gram-negative) and in vitro antifungal activity against two pathogenic fungal strains namely, Candida albicans and Saccharomyces cerevisiae. All the synthesized compounds showed activity against Gram-positive bacteria.

Synthesis of novel celecoxib analogues by bioisosteric replacement of sulfonamide as potent anti-inflammatory agents and cyclooxygenase inhibitors.

Two series of celecoxib analogues having 1,5-diaryl relationship were synthesized. The key strategy of the molecular design was oriented towards exploring bioisosteric modifications of the sulfonamide moiety of celecoxib. First series (2a-2i) of celecoxib analogues bearing cyano functionality in place of sulfonamide moiety was synthesized by the reaction of appropriate trifluoromethyl-β-diketones (5a-5i) with 4-hydrazinylbenzonitrile hydrochloride (4) in ethanol.