AN EFFICIENT MICROWAVE-PROMOTED THREE-COMPONENT SYNTHESIS OF THIAZOLO[3,2-<i>a</i>]PYRIMIDINES CATALYZED BY SiO<sub>2</sub>–ZnBr<sub>2</sub> AND ANTIMICROBIAL ACTIVITY EVALUATION

Authors

  • Subba Rao Devineni Institute of Surface-Earth System Science, Tianjin University, 92 Weijing Road, Tianjin-300072
  • Thirupal Reddy Madduri Department of Chemistry, Sri Venkateswara University, Tirupati-517502, Andhra Pradesh
  • Naga Raju Chamarthi Department of Chemistry, Sri Venkateswara University, Tirupati-517502, Andhra Pradesh
  • Cong-Qiang Liu Institute of Surface-Earth System Science, Tianjin University, 92 Weijing Road, Tianjin-300072
  • Chandra Mouli Pavuluri Institute of Surface-Earth System Science, Tianjin University, 92 Weijing Road, Tianjin-300072

DOI:

https://doi.org/10.1007/4802

Keywords:

diisopropylethylamine, 2-(4-nitrophenyl)acetonitrile, silica-supported zinc bromide, thiazol-2-amine, thiazolo[3, 2-a]pyrimidine, antimicrobial activity, microwave-assisted synthesis, multicomponent reaction

Abstract

One-pot three-component Biginelli-type reaction of substituted thiazol-2-amines, 2-(4-nitrophenyl)acetonitrile, and aromatic aldehydes, promoted by heterogeneous catalyst SiO2–ZnBr2 and diisopropylethylamine as base, has been developed for the synthesis of 2,5-substituted-6-(4-nitrophenyl)-5H-thiazolo[3,2-a]pyrimidin-7-amines. This method, optimized under microwave conditions, was highly efficient and environmentally benign and delivered the desired products in good yields (89–96%) in short reaction time (<6 min). The method has many additional advantages such as wide substrate tolerance, high atom economy, operational simplicity, reusability of the catalyst, and inexpensive solvent. In screening tests of antimicrobial activity against four bacteria and three fungi species, few of the synthesized compounds showed activity in the MIC range 6.25–25.0 μg/ml, which was close to the standard drugs, tetracycline and amphotericin B (MIC 3.125–6.25 μg/ml).

Published

2019-04-11

Issue

Section

Original Papers