Muthupandi Nagaraj

Copper(I)-Catalyzed Cascade Sulfonimidate to Sulfonamide Rearrangement: Synthesis of Imidazo[1,2-a][1,4]diazepin-7(6H)-one

A novel strategy of copper(I)-catalyzed cascade intramolecular nucleophilic attack on N-sulfonylketenimine followed by rearrangement of sulfonimidates to sulfonamides resulting in a library of substituted 8,9-dihydro-5H-imidazo[1,2-a][1,4]diazepin-7(6H)-ones has been developed.

Aggregation induced emission characteristics of maleimide derivatives

A simple microwave assisted protocol for the construction of maleimides from various anilines and dialkyl acetylene dicarboxylates has been demonstrated. The AIE property of one of the maleimide derivatives has been studied in detail. The maleimide is AIE-active, and its color, fluorescence efficiency, quantum yield and fluorescence lifetime can be readily tuned by adding water to the THF solution. Compound 3a is found to be weakly luminescent when it is dissolved in THF, but its luminescence intensity increases enormously by the gradual addition of water up to 90% with associated increase in quantum yield and fluorescence lifetime.

Synthesis of Highly Substituted N-Hydroxy Piperidine via Intramolecular Reductive Cyclization of 1-Keto-5-ketoxime

Abstract Diasteroselective synthesis of highly substituted N-hydroxypiperidine was achieved by an intramolecular reductive cyclization of monoxime (2) of the 1,5-diketone (1), generated from 2-(cyclohexylthio)-1-phenylethanone and arylaldehyde, using NaBH3CN. The major product N-hydroxypiperidine (3) has been found to be racemate of a single diastereomer. GRAPHICAL ABSTRACT

Synthesis of cyclic nitrone and 1,2-oxazine from 1,2,4-triaryl-but-2-ene-1,4-dione and hydroxylamine

AbstractThe reaction of hydroxylamine hydrochloride with differently substituted phenyldibenzoylethylene has been investigated. Both cyclic nitrone and 1,2-oxazine have been isolated and characterized by one- and two-dimensional NMR data and also by single crystal X-ray analysis. Graphical AbstractThe reaction of hydroxylamine hydrochloride with differently subtituted phenyldibenzoylethylene has been investigated. Both cyclic nitrone and 1,2-oxazine have been isolated and characterized by one- and two-dimensional NMR data and also by single crystal X-ray analysis.

Transition metal-free, base-promoted hydroalkoxylation: Synthesis of substituted imidazo[2,1-c][1,4]oxazines

AbstractAn efficient, transition metal-free method to synthesize substituted imidazo[2,1-c][1,4]oxazine derivatives via hydroalkoxylation of 1,5-alkynyl alcohol has been described. The reaction proceeds regioselectively with exclusive formation of 6-exo-dig product. Graphical AbstractAn efficient, transition metal-free method to synthesize substituted imidazo[2,1-c][1,4]oxazine derivatives via hydroalkoxylation of 1,5-alkynyl alcohol has been described. The reaction proceeds regioselectively with exclusive formation of 6-exo-dig product.

Selenium dioxide reaction of substituted diphenacyl sulfides: generation of α -ketoacids

The attempted selenium dioxide oxidation of substituted diphenacyl sulfides in anticipation of further functionalization led to a series of α -ketoacids 3 via oxidation followed by C‒S bond cleavage. Two minor products, 5 and 6, have also been isolated and a mechanistic pathway for the formation of 3, 5 and 6 has been proposed. GRAPHICAL ABSTRACT

Base free regioselective synthesis of α-triazolylazine derivatives

A regioselective α-heteroarylation followed by deoxygenation towards the synthesis of variety of azine triazole from simple azine N-oxides derivatives and N-tosyl-1,2,3-triazoles has been described. The reaction is metal free and base free with shorter reaction time, high yields and a broad substrate scope.

Three component synthesis of 2-oxindole via sequential Michael addition, intramolecular cyclization and aromatization

An easy metal free access to the synthesis of medicinally promising 2-oxindole derivatives via a tandem enamine formation – Michael addition – regiospecific intramolecular cyclization – aromatization sequence promoted by trifluoroacetic acid has been described. This three component reaction is regiospecific with good yield and satisfactory atom economy.