APPLICATIONS OF MICROWAVE ENERGY IN ORGANIC CHEMISTRY. A REVIEW

Microwave assisted oxidation of some aromatics by hydrogen peroxide at supported tungsten catalyst

The oxidation of some arenes with the alkyl side groups by means of hydrogen peroxide is been presented. As the activator of hydrogen peroxide tungstoboric acid was chosen. The catalyst was examined under both homogeneous and heterogeneous conditions. The reactions under conventional conditions were compared with the microwave assisted reactions.

Efficient Solvent-Free Selective Monoalkylation of Arylacetonitriles with Mono-, Bis-, and Tris-primary Alcohols Catalyzed by a Cp*Ir Complex

Our objectives were to develop catalytic atom-economic processes accessing and/or incorporating versatile functionality using aryl/heteroaryl acetonitriles as substrates. We report essentially solvent-free [Cp*IrCl2]2 catalyzed redox neutral processes whereby substituted acetonitriles react with primary alcohols to deliver monosubstituted aryl/heteroaryl acetonitriles in excellent yield. We further demonstrate that such processes can be achieved by conventional or microwave heating and that bis- and tris-primary alcohols are also processed efficiently.

Efficient microwave enhanced regioselective synthesis of a series of benzimidazolyl/triazolyl spiro [indole-thiazolidinones] as potent antifungal agents and crystal structure of spiro[3H-indole-3,2′-thiazolidine]-3′(1,2,4-triazol-3-yl)-2,4′(1H)-dione

A microwave-assisted three-component, regioselective one-pot cyclocondensation method has been developed for the synthesis of a series of novel spiro[indole-thiazolidinones] (6a-l) using an environmentally benign procedure at atmospheric pressure in open vessel. This rapid method produces pure products in high yields within few minutes in comparison to a conventional two-step procedure. The crystal structure of one representative compound has been determined by X-ray diffraction. The synthesized compounds have been screened 'in vitro' for antifungal activity against Rhizoctonia solani, Fusarium oxysporum and Collectotrichum capsici. All compounds have shown good activity against these pathogens.

Reactions of 3-formylchromone with active methylene and methyl compounds and some subsequent reactions of the resulting condensation products

This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the gamma-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted.

Deprotection of Thioacetal Using 1-butyl-4-aza-1-azoniabicyclo[2.2.2] Octane Dichromate (BABOD) in the Presence of AlCl3

A variety of thioacetal (2) are deprotected to parent carbonyl compounds (3) using 1-butyl-4-aza-1-azoniabicyclo[2.2.2] octane dichromate (BABOD) (1) in the presence of AlCl3 in refluxing CH3CN.

Solventless Rapid Synthesis of Oxime, Semicarbazone, and Phenylhydrazone Derivatives from Carbonyl Compounds under Microwave Conditions

A rapid and efficient method for the synthesis of oximes, semicarbazones, and phenylhydrazones has been reported under solventless conditions using microwave irradiation.

Solvent Free Rapid Synthesis of 3-Alkoxycyclohex-2-en-1-one from 1,3-Cyclohexanedione Promoted by Indium(III) Chloride/Silica Gel

A convenient and environmentally friendly method for the synthesis of 3-alkoxycyclohex-2-en-1-one 1 from cyclohexane-1,3-dione on the surface of silica gel impregnated with indium(iii) chloride under microwave irradiation without any solvent has been reported.