Natural dolomitic limestone catalyzed synthesis of benzimidazoles, dihydropyrimidinones and highly substituted pyridines under ultrasound irradiation

  1. Kumar Godugu,
  2. Venkata Divya Sri Yadala,
  3. Mohammad Khaja Mohinuddin Pinjari,
  4. Thrivikram Reddy Gundala,
  5. Lakshmi Reddy SanapareddyORCID Logo and
  6. Chinna Gangi Reddy NallagonduORCID Logo

Submitting author affiliation: Yogi Vemana University, Kadapa, India

Beilstein Arch. 2020, 202039.

Published 02 Apr 2020

  • Preprint


In this paper, for the first time, naturally occurring dolomitic limestone is employed as a heterogeneous green catalyst for the synthesis of medicinally valuable N-heterocycles, 2-aryl-1-arylmethyl-1H-benzo[d]imidazoles, dihydropyrimidinones/ thiones and 2-amino-4-aryl-3,5-dicarbonitrile-6-sulfanyl-pyridines in good to excellent isolated yields via a rapid construction of C-N, C-C and C-S bond formations in 1:1 ratio of ethanol:H2O under ultrasound irradiation. Dolomitic limestone is characterized by X-ray diffraction (XRD), FT-IR, Raman and SEM with EDAX analyses. Further, the catalyst is environmentally benevolent, non-toxic, most abundant, easy to handle low catalyst loading and is reused 7 times without significant loss of catalytic activity. Hence, the catalyst is greener alternative for the synthesis of aforementioned N-heterocycles as compared with the existing reported catalysts.

Keywords: Natural dolomitic limestone; ultrasound irradiation; benzimidazoles; dihydropyrimidinones; highly substituted pyridines

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Godugu, K.; Yadala, V. D. S.; Pinjari, M. K. M.; Gundala, T. R.; Sanapareddy, L. R.; Nallagondu, C. G. R. Beilstein Arch. 2020, 202039. doi:10.3762/bxiv.2020.39.v1

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