Microwave organic reaction enhancement MORE

Microwave organic reaction enhancement (MORE) chemistry was described by Bose as a safe and convenient alternative to pressure reactions and modified microwave ovens [20]. 

Bose, A.K. and Manhas, M.S., Banik, B.K. and Robb, E.W., Microwave-induced organic-reaction enhancement (MORE) chemistry - techniques for rapid, safe and inexpensive synthesis, Res. Chem. Intermed., 1994, 20, 1-11. 

Shiradkar et al. [19] reported the synthesis of clubbed thiazolyl triazole derivatives (vii) starting from ethyl acetoacetate, by microwave organic reaction enhanced method (MORE). The synthesized triazoles showed promising antimicrobial and antimycobacterial activities. 

If the product is needed on a small scale, up to 100 g, the reaction can be scaled out rather than scaled up. The excellent reproducibihty together with automation can easily produce up to 100 g overnight. Bose et al. have described an alternative for minor scale-up where the use of the microwave-assisted organic reaction enhancement (MORE) technique reduces the need for organic solvents and increases atom economy by improving product selectivity and chemical yield, thus, minimizing the need for larger scale-up. 

By using the microwave-induced organic reaction enhancement (MORE) method Balasubramanian et al. [41] achieved solvent-free glycosylations by treating tri-O-acetyl-D-glucal 49 with substituted phenols to afford 2,3-unsaturated O-aryl glycosides 50 reaction times reduced several fold compared with those required under thermal conditions (Scheme 12.24). 

Differential heating is more easily achieved with microwave technology than by conventional conductive methods and as Cundy suggested in his excellent review, could well account for apparent rate enhancements obtained by others with organic reactions on dry media [40]. 

Investigations using hydrotrope solutions in reaction kinetics have varied from the direct analysis of the influence on the kinetics by the solubilization per se [29] of aromatic esters to more elaborate reaction systems. Microwave heating was early shown as an efficient way to enhance organic reactions [30,31], However, the use of common organic solvents causes environmental problems in connection with microwave heating and aqueous solutions offer safe and convenient... 

In the thermal studies, the reactants were mixed (in the absence of a solvent) with palladium doped, potassium fluoride treated alumina and the mixture heated for four or more hours at temperatures approaching 100 In this portion of the study, we examined the effectiveness of microwave irradiation for enhancing the rate of the reactions. The feasibility of using microwave irradiation to induce organic reactions on solid surfaces in the absence of solvents has been demonstrated previously. As a probe, we investigated the reaction of tolylboronic acid with iodobenzene for various time periods. Table V. 2-Methylbiphenyl was formed readily under a variety of reaction conditions. For convenience, we found it most efficient to simply heat the mixtures for 2 minutes at 100% power. Under these conditions, a small amount of organic material could be observed condensing on the cooler portions of the reaction vessel. 

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