Enhanced microwave synthesis

Gizdavic-Nikolaidis, M. R., Stanisavljev, D. R., Easteal, A. J., and Zujovic, Z. D. Enhanced microwave synthesis Fine-tuning of polyanUine polymerization. JPhys Chem C 116, 3235-3241 (2012). 

The most successful application of microwave energy in the preparation of heterogeneous solid catalysts has been the microwave synthesis and modification of zeolites [21, 22], For example, cracking catalysts in the form of uniformly sized Y zeolite crystallites were prepared by microwave irradiation in 10 min, whereas 10-50 h were required by conventional heating techniques. Similarly, ZSM-5 was synthesized in 30 min by use of this technique. The rapid internal heating induced by microwaves not only led to a shorter synthesis time, and high crystallinity, but also enhanced substitution and ion exchange [22]. 

Microwave processing of zeolites and their application in the catalysis of synthetic organic reactions has recently been excellently reviewed by Cundy [23] and other authors [24], The microwave synthesis of zeolites and mesoporous materials was surveyed, with emphasis on those aspects which differ from conventional thermal methods. The observed rate enhancement of microwave-mediated organic synthesis... 

Parallel to these developments in combinatorial chemistry, microwave-enhanced organic synthesis has attracted a substantial amount of attention in recent years. As evidenced from the other chapters in this book and the large number of review articles available on this subject [7-14], high-speed microwave-assisted synthesis has... 

Santagada, V., Perissutti, E., Fiorino, F., Vivenzio, B. and Caliendo, G., Microwave enhanced solution synthesis... 

In order to investigate dendrimers of a different nature [230], Bradley described the synthesis and transfection efficiency of polyamidourea dendrimers synthesised from isocyanate-containing AB3 monomers [231-234]. The use of this kind of tris-branched building block was addressed to enhance dendrimer synthesis by replacement of the 1,4-addition step typical of PAMAM synthesis and to a rapid increase in terminal functionality. The dendritic structures were synthesised using a divergent, microwave-assisted, solid-phase approach with the dendrimers assembled on polystyrene resin via an acid labile linker (see Fig. 26). In particular, a G3.0 polyamidourea bis-dendron with the peripheral amino groups conjugated to L-lysine residues demonstrated remarkable transfection abilities [234],... 

Abstract Increasing reaction speed and simplifying product purification are two major ways to improve the efficiency of organic synthesis. A new technology for high-speed solution-phase synthesis has been developed by combination of microwave heating and fluorous purification. This review describes different techniques for microwave-enhanced fluorous synthesis and their applications in Pd-catalyzed cross-coupling reactions, free-radical reactions, multicomponent reactions, and compound library synthesis. 

Regardless of the nature of the observed rate-enhancements ( microwave effects [19,20]), which will undoubtedly be an ongoing debate for many years in the academic world, microwave synthesis has now truly matured and has moved from a laboratory curiosity in the late 1980s to an established tech-... 

Dandia A, Singh R, Khaturia S et al (2006) 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, 20-thiazolidine]-30(l, 2, 4-triazol-3-yl)- 2, 40(lH)-dione. Bioorg Med Chem 14 2409-2417... 

Subsequently, Xu et al. studied the microwave-enhanced ionothermal synthesis of aluminophosphate molecular sieves.[113] By using the ionic liquid l-ethyl-3-... 

Microwave-assisted polycondensation reactions in ILs have also allowed the enhanced synthesis of polyamides and polyurethanes the comparison between microwave synthesis conditions in ILs with conventional heating methods and conventional organic solvents has also been addressed [92, 93]. Pretreatment methods combining microwave irradiation and ILs for cellulose dissolution and modification have been also proposed [94, 95]. Microwave irradiation can enhance the solubility of cellulose in ILs and decrease the degree of polymerization of regenerated cellulose after IL dissolution, which can be beneficial for improving cellulose hydrolysis [95]. 

A novel use ofthe salt [BMIM][PF6] is to enhance microwave absorption and hence accelerate the rate of a reaction. Ley found that [BMIM][PF6] enhanced the rate of the microwave promoted thionation of amides using a polymer supported thionating agent [304]. Hardacre et al. have developed a protocol for the synthesis of deuterated imidazoles and imidazolium salts [305]. The procedure involves the platinum- or palladium- catalyzed deuterium exchange of 1-methyl-d -imidazole with D2O to give 1-methylimidazole-d , followed by reaction with a deuterated alkyl halide. 

Furthermore, microporous materials can be easily achieved by microwave synthesis in an efficient way by controlling particle size distribution and phase selectivity, and because of its unique morphology and enhanced crystallisation time (Park et al., 1998 Suresh et al., 2014). 

Xu Y Tian Z, Wang S, Hu Y, Wang L, Wang B, et al. Microwave-enhanced ionothermal synthesis of aluminophosphate molecular sieves. Angew Chem Int Ed 2006 45 3965-70. 

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