Reaction microwave irradiation

Similar results were obtained in the esterification of acetic acid with 1-propanol performed in the presence of a heterogeneous silica catalyst [39]. The results showed that for this reaction microwave irradiation and conventional heating had similar effects on the reaction rate. 

To decrease the reaction time required for the conventional treatment (from 2 up to 48 h) and to improve the conversion level of the reaction, microwave irradiation was successfully applied for obtaining 4-thiazolidinones substituted with azole ring. Siddiqui et al. [174] reported the efficient microwave-assisted solid-supported approach for one-pot diastereoselective synthesis of some analogs of fungitoxic dibenzyles. 

In the McFadyen-Stevens reaction, microwave irradiation has also been employed to convert carboxylic acids to aldehydes via the p-toluenesulphonyl hydrazides65. The p-toluenesulphonyl hydrazide is mixed with sodium carbonate, glass powder and ethylene glycol, and pre-irradiated at 150 W for a few minutes before the actual reaction conditions were applied. The reaction was successfully used in the synthesis of the alkaloid Nauclefidine (Scheme 4.40). 

Keywords aldehyde, cross-Cannizzaro reaction, microwave irradiation, alcohol... 

Keywords nitroalkane, aromatic aldehyde, Henry reaction, microwave irradiation, nitroalkene... 

Keywords aromatic hydroxyaldehyde, ethyl malonate, methyl malonate, Knoe-venagel reaction, microwave irradiation, 3-substituted coumarin... 

Keywords chalcone, Michael reaction, microwave irradiation, flavanone... 

Keywords ketone, phosphorus ylide, Wittig reaction, microwave irradiation, ole-... 

Keywords pyrrolidino[60]fullerene, phase transfer reaction, microwave irradiation, A-alkylpyrrolidino[60]fullerene... 

Keywords alcohol, nitrile, montmorillonite KSF, Ritter reaction, microwave irradiation, amide... 

Keywords aromatic aldehyde, primary amine, malonic acid monoethyl ester, Rodionov reaction, microwave irradiation, / -aryl-/ -amino acid ester, ethyl cinna-mate... 

Keywords active methylene compound, LiBr, nitroso arene, Ehrlich-Sachs reaction, microwave irradiation, imine... 

The use of domestic microwave and automated oven in organic synthesis is well established (Microwave activation has become a very popular and useful technology in organic and medicinal chemistry. For some recent examples, see [128-131]). This is particularly very noteworthy because of the unconventional set up necessary for conducting the reaction. Microwave irradiation of a solution of imines 21, 23, and 29 with acetoxyacetyl chloride in chlorobenzene using a domestic and... 

Keywords Green chemistry Organic synthesis Solvent-free reactions Microwave irradiation Ultrasonic irradiation Mechanochemical mixing Aqueous media... 

Other reactions. Microwave irradiation of 3-phenyl-2-isoxazolin-5-one (159) in the presence of KF on alumina, without any solvent, reacted with aromatic aldehydes (160) to afford 4-(arylmethylene) derivatives (161) (Equation (31)) <93SC16>. The fused bicyclic-isoxazoline (162) underwent a thermal retro-Diels-Alder reaction and resulted in a mixture of 3-phenyl isoxazole (163) and norborn-eneadduct (164) (Equation (32)) <90MRC1023>. 

Romanova [80] studied the effect of microwave irradiation on the direction and stereochemistry of the Rodionov reaction. Microwave irradiation of a mixture of equimolecular amounts of benzylammonium acetate 128, monoethyl malonate 130, and 2-phenylpropanal 127 resulted in the formation of yS-amino ester 132 in 38% yield and ethyl-4-phenyl-2-pentenoate 133 in 60% yield, exclusively as the trans isomer (Scheme 5.36). By contrast, thermal activation does not lead to forma-... 

A bimetallic catalyst based on Cu-Mn spinel oxide was used for azide-alkyne reactions. Microwave irradiation conditions were required due to its low intrinsic catalytic activity. It was observed that Mn significantly influenced the efficiency and selectivity of the bimetallic catalyst (Yousuf et al., 2010). Nanoporous Cu catalysts (CuNPore) can be employed for the efficient assembly of 1,2,3-triazoles (Jin et al., 2011). Additionally, their tunable ligament sizes have a significant impact on the catalytic activity. Bharate et al. reported a recyclable clay-supported, Cu(II)-catalyzed, one-pot synthesis of 1,2,3-triazoles (Mohammed et al., 2012). In this case, montmorillonite KSF clay-supported CuO nanoparticles efficiently promoted the one-pot aromatic azidonation of the arylboronic acids/azide-alkyne cycloaddition process at room temperature. 

Microwave irradiation is known to enhance the rate of various reactions. Normally, CROP reactions of ROZOs proceed relatively slowly, by taking some hours to complete the reaction. To accelerate the reaction, microwave irradiation method was applied and found very effective for the reaction, which has been extensively developed recently. 

---