Microwave-Induced Solvent-Free Synthesis and Antifungal Screening of Novel Spiro Heterocyclic Systems Containing 3,5-Diphenyl-7H-thiazolo[3,2-a]pyrimidine and Indolin-2-one

Abstract

A microwave-induced technique has been developed for the synthesis of a series of novel spiro indoline-based heterocycles (7a–g) at atmospheric pressure in an open vessel using an environmentally benign procedure. This rapid method produces pure products in good yields within a few minutes in comparison to the conventional procedure developed for the synthesis of these heterocycles. The synthesized compounds have been screened in vitro for antifungal activity against two fungal strains (i.e., Aspergillus niger and Aspergillus flavus). All compounds have shown significant activity against these pathogens.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]

GRAPHICAL ABSTRACT

Keywords:

• Michael addition
• microwave-assisted solvent-free synthesis
• solid support technique
• spiro indoline-based heterocycles

ACKNOWLEDGMENTS

We sincerely thank SAIF, Punjab University, Chandigarh for providing microanalysis and spectra. The authors are also grateful to the Council of Scientific and Industrial Research New Delhi, for providing financial support in terms of junior and senior research fellowships.

Notes

^a Yield of the isolated products.

^b Yield under identical thermal conditions of time and temperature as under micrcowaves.

^c Yield under thermal condition (at same temperature as in the case of MW), after extended time.

^a Yield of the isolated products.

^b Yield under identical thermal conditions of time and temperature as under microwaves.

^c Yield obtained after extension of reaction time up to 360 min at similar temperature (under same conditions as MW).

Time and yield for the compounds isolated from conventional method (using 1,4-dioxane) and microwave-assisted method using basic alumina as solid support.

^a Each value is the mean of three independent experiments.