Arumugam Mariappan

Erbium triflate promoted multicomponent synthesis of highly substituted imidazoles.

The synthesis of highly substituted imidazole derivatives has been achieved from various α-azido chalcones, aryl aldehydes, and anilines. This multicomponent protocol employs erbium triflate as a catalyst resulting in excellent yield of the imidazoles.

Hypervalent Iodine(III) Mediated Synthesis of 3-Substituted 5-Amino-1,2,4-thiadiazoles through Intramolecular Oxidative S–N Bond Formation

An efficient synthesis of 3-substituted-5-arylamino-1,2,4-thiadiazoles through intramolecular oxidative S-N bond formation of imidoyl thioureas by phenyliodine(III) bis(trifluoroacetate) is reported. The protocol features a metal-free approach, broad substrate scope, very short reaction times, good to excellent yields, and simple starting materials.

Investigation on the reactivity of α-azidochalcones with carboxylic acids: Formation of α-amido-1,3-diketones and highly substituted 2-(trifluoromethyl)oxazoles

Summary The reaction of α-azidochalcones with carboxylic acids has been investigated resulting in the formation of α-amido-1,3-diketones under microwave irradiation via in situ formation of 2H-azirine intermediates. An interesting reaction is described wherein, with trifluoroacetic acid at lower temperature, it affords highly substituted 2-(trifluoromethyl)oxazoles. These flexible transformations proceed under solvent free conditions in good to excellent yields without any catalyst.

An environmentally benign solvent/catalyst-free one-pot synthesis of N-substituted phthalimides via Aza-wittig reaction

For the first time an environmentally benign solvent/catalyst-free protocol for the synthesis of a variety of N-substituted phthalimides is submitted. It involves a one-pot coupling of nascent phosphazene generated in situ with phthalic anhydride. The protocol is novel in (1) avoiding toxic solvents, (2) no catalyst is employed and (3) no isophthalimide is formed as noted in the prevailing solution phase/catalysed methodology.

Divergent reactivity of α-azidochalcones with metal β-diketonates: tunable synthesis of substituted pyrroles and indoles

A divergent reactivity of α-azidochalcones with metal β-diketonates for the synthesis of substituted pyrroles and indoles is described. Metal β-diketonates have been applied as bifunctional reactive partners. With a copper complex, the synthesis of substituted pyrroles in micellar media via 2H-azirine intermediates has been achieved under mild conditions, while with Fe(acac)2 as a catalyst, the reaction proceeds smoothly to yield indoles regioselectively.

Microwave-assisted catalyst-free synthesis of tetrasubstituted pyrroles using dialkyl acetylenedicarboxylates and monophenacylanilines

ABSTRACT An efficient catalyst-free microwave-assisted synthesis of tetrasubstituted pyrroles using dialkyl acetylenedicarboxylates and substituted monophenacylanilines has been developed. Axial chirality has been noticed in some N-(α-naphthyl/2-isopropylphenyl)-2,3-dicarbethoxy-4-arylpyrroles, but not with N-aryl-2,3-dicarbethoxy-4-(α-naphthyl)pyrrole. GRAPHICAL ABSTRACT