The benzazole scaffolds are present in various therapeutic agents and have been
recognized as the essential pharmacophore for diverse biological activities. These have generated
interest and necessity to develop efficient synthetic methods of these privileged classes of
compounds to generate new therapeutic leads for various diseases. The biological activities of
the benzazoles and efforts towards their synthesis have been summarized in a few review articles.
In view of these, the aim of this review is to provide an account of the developments that
have taken place in the synthesis of biorelevant benzazoles under microwave irradiation as the
application of microwave heating has long been recognized as a green chemistry tool for
speedy generation of synthetic targets. Attention has been focused to those literature reports
wherein the use of microwave irradiation is the key step in the formation of the heterocyclic
ring system or in functionalization of the benzazole ring system to generate the essential
pharmacophoric feature. The convenient and economic way to synthesize these privileged
class of heterocycles through the use of microwave irradiation that would be beneficial for the
drug discovery scientist to synthesize biologically active benzazoles and provide access to
wide range of reactions for the synthesis of benzazoles constitute the theme of this review.
Examples have been drawn wherein the use of microwave heating offers distinct advantage in
terms of improved product yields and reduction of reaction time as compared to those observed
for the synthesis under conventional heating.
Keywords: 2-Aminophenol, 2-aminothiophenol, ortho-phenylenediamine, carboxylic acids, aldehyde, benzoxazole,
benzothiazole, benzimidazole, bis-heterocyclic scaffolds, fused ring system, bio-activity, catalyst-free reaction, solvent-
free reaction, solid-support, conventional heating, microwave irradiation, multi-component reaction, one-pot
reaction, domino reaction, michael reaction, green chemistry.
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