1,3,4-oxadiazoles, microwave-assisted synthesis

From a medicinal chemist s point of view, oxadiazoles are among the most important heterocycles as they are one of the most commonly used bioisosters for amide and ester groups [67]. As such it is hardly surprising that the two regioisomeric oxadiazole scaffolds received the most interest in the field of microwave-assisted synthesis using polymer-supported reagents. 

Nicewonger R, Baldino C, Evans M (2003) The accelerated development of an optimized synthesis of 1,2,4-oxadiazoles. Tetrahedron Lett 44 9337-9341 Ondruschka B, Nuchter M, Bonrath W (2004) Microwave assisted synthesis— a critical technology overview. Green Chem 6 128-141 Regan J, Breitfelder S Cirillo P (2002) Pyrazole urea-based inhibitors of p38 MAP kinase from lead compound to clinical candidate. J Med Chem 45 2994-3008... 

Kidwai, M., Kumar, P., Goel, Y. and Kumar, K., Microwave assisted synthesis of 5-methyl- 1,3,4-thiadiazol-2-ylthio/tetrazol-l-yl substituted pyrazoles, 2-azetidinones, 4-thiazolidinones, benzopyran-2-ones and 1,3,4-oxadiazoles, Indian. J. Chem., Sect. B, 1997, 36, 281. 

The microwave assisted synthesis of new lanthanum (III) and praseodymium (III) complexes with oxadiazole functionalized dithiocarbazinates, [M(L)3] is described [40]. 

Han et al. [41] gave the microwave assisted synthesis of novel alkyl substituted fructose-based oxadiazoles and investigated them for their cytotoxic activity... 

Xu et al. [44] reported the microwave assisted synthesis and antifungal activity of 2,5-disubstituted-l,3,4-oxadiazoles containing azulene moiety. The 5-aryl-2-(3-methylazulen-l-yl)-l,3,4-oxadiazoles (Lv) were obtained by the microwave... 

Frank PV, Girish KS et al (2007) Solvent-free microwave-assisted synthesis of oxadiazoles containing imidazole moiety. J Chem Sci 119 41 6... 

Adib M, Jahromi AH, Tavoosi N et al (2006) Microwave-assisted efficient, one-pot, three-component synthesis of 3, 5-disubstituted 1, 2, 4-oxadiazoles under solvent-free conditions. Tetrahedron Lett 47(17) 2965-2967... 

Sangshetti JN, Chabukswar AR et al (2011) Microwave assisted one-pot synthesis of some novel 2,5-disubstituted 1,3,4-oxadiazoles as antifungal agents. Bioorg Med Chem Lett 21 444-448... 

Natero R, Koltun DO et al (2004) Microwave-assisted one-step synthesis of substituted 2-chloromethyl-l,3,4-oxadiazoles. Synth Commun 34 2523-2529... 

Wang LN, Han D et al (2009) Microwave-assisted efficient synthesis of glucose-based 3-acetyl-5-alkyl-2,3-dihydro-l,3,4-oxadiazole derivatives catalyzed by sodium acetate. Carbohydr Res 344 2113-2119... 

The development of modem and reliable procedures for microwave-assisted organic synthesis has also been used advantageously for 1,2,4-oxadiazole synthesis by avoiding time-consuming steps, using green solvents or solvent-free conditions, or by directly employing acids rather... 

Scheme 6.21 Microwave assisted convenient synthesis of 7-(5-alkyl-l,3,4-thiadiazol/oxadiazol-...

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