Diacetoxy iodobenzene mediated regioselective synthesis and characterization of novel [1,2,4]triazolo[4,3-a]pyrimidines: apoptosis inducer, antiproliferative activities and molecular docking studies

Abstract

Prompt and regioselective synthesis of eleven novel [1,2,4]triazolo[4,3-a]pyrimidines 2a-2k, via intramolecular oxidative-cyclization of 2-(2-arylidenehydrazinyl)-4-methyl-6-phenylpyrimidine derivatives 1a-1k has been demonstrated here using diacetoxy iodobenzene (DIB) as inexpensive and ecofriendly hypervalent iodine(III) reagent in CH₂Cl₂ at room temperature. Regiochemistry of final product has been established by developing single crystal and studied X-ray crystallographic data for two derivatives 2c and 2h without any ambiguity. These prominent [1,2,4]triazolo[4,3-a]pyrimidines were evaluated for human osteosarcoma bone cancer (MG-63) and breast cancer (MCF-7) cell lines using MTT assay to find potent antiproliferative agent and also on testicular germ cells to find potent apoptotic inducing activities. All compounds show significant cytotoxicity, particularly 3-(2,4-dichlorophenyl)-5-methyl-7-phenyl-[1,2,4]triazolo[4,3-a]pyrimidine (2g) was found significant apoptotic inducing molecule, as well as the most potent cytotoxic agent against bone cancer (MG-63) and breast cancer (MCF-7) cell lines with GI₅₀ value 148.96 µM and 114.3 µM respectively. Molecular docking studies has been carried out to see the molecular interactions of synthesized compounds with the protein thymidylate synthase (PBD ID: 2G8D).

Communicated by Ramaswamy H. Sarma

Keywords:

• [1,2,4]triazolo[4,3-a]pyrimidines
• regioselective
• apoptosis
• antiproliferative activity
• thymidylate synthase

Acknowledgements

The authors are very grateful to Kurukshetra University, Kurukshetra (Haryana) for providing lab facilities and UGC, New Delhi for the financial support in form of UGC-SRF to Mr. Ravinder Kumar. The authors also express their deepest gratitude to Dr. Avijit Paul at NIT, Kurukshetra, Haryana (India) for characterization and refinement of single crystal data. We are also thankful to Central Instrumentation Laboratory, GJUS&T, Hisar (Haryana) and Material Research Centre, MNIT, Jaipur (Rajasthan) for NMR and HRMS analysis respectively.

Disclosure statement

The authors declare no conflict of interest