Green MW/US-Assisted Construction of Pyrano[2,3-b]pyridines and Pyrazolo[3,4-d]pyrimidinones: Pathway Control and Antibacterial Evaluation.
4 affiliations
- 1Department of Chemistry, College of Science, Majmaah University, Al-Zulfi, Riyadh, Saudi Arabia.
- 2Chemistry Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia.
- 3Department of Green Chemistry, National Research Centre, Cairo, Egypt.
- 4Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
Abstract
A green, activation-controlled route was examined for the preparation of biologically relevant fused N/O heterocycles, with particular emphasis on whether the mode of energy delivery can redirect the reaction pathway. A single hydrazine-derived precursor was treated with acetic anhydride under the same nominal temperature and reaction time while applying ultrasound (US), microwave (MW), or combined MW/US activation. The three modes led selectively to different annulated products: pyrazolo[3,4-d]pyrimidinone 5 was isolated in 88% yield under US, oxazinyl-pyrazolidinone 6 in 85% yield under MW, and the more extensively fused derivative 7 in 85% yield under combined MW/US conditions. These results indicate that pathway selection can be influenced by the physical manner in which energy is supplied without altering the reagent set. The products were assigned from FT-IR, NMR, EI-MS, and elemental-analysis data and were screened against representative Gram-positive and Gram-negative bacteria. Compound 5 gave the best overall antibacterial response, including a 32.0 ± 0.6 mm inhibition zone against Staphylococcus aureus and MIC values of ≤ 12.5 µg/mL. Its experimental performance was consistent with favorable docking contacts and stable molecular-dynamics behavior, while DFT/Mulliken analysis provided a rationale for the reactive sites involved in annulation and dehydration.
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BibTeX
@article{alhunayhin2026green,
title = {{Green MW/US-Assisted Construction of Pyrano[2,3-b]pyridines and Pyrazolo[3,4-d]pyrimidinones: Pathway Control and Antibacterial Evaluation.}},
author = {Sultanah M Alhunayhin and Ayman M Algohary and Youssef O Al-Ghamdi and Mohamed Abdel-Megid and Asmaa M Fahim and Sameh A Rizk},
journal = {Chemistry \& biodiversity},
year = {2026},
month = oct,
doi = {10.1002/cbdv.71844},
url = {https://europepmc.org/article/MED/42904607},
note = {CC BY},
}
RIS
TY - JOUR
TI - Green MW/US-Assisted Construction of Pyrano[2,3-b]pyridines and Pyrazolo[3,4-d]pyrimidinones: Pathway Control and Antibacterial Evaluation.
AU - Sultanah M Alhunayhin
AU - Ayman M Algohary
AU - Youssef O Al-Ghamdi
AU - Mohamed Abdel-Megid
AU - Asmaa M Fahim
AU - Sameh A Rizk
PY - 2026
DA - 2026/10/01
JO - Chemistry & biodiversity
DO - 10.1002/cbdv.71844
UR - https://europepmc.org/article/MED/42904607
AB - A green, activation-controlled route was examined for the preparation of biologically relevant fused N/O heterocycles, with particular emphasis on whether the mode of energy delivery can redirect the reaction pathway. A single hydrazine-derived precursor was treated with acetic anhydride under the same nominal temperature and reaction time while applying ultrasound (US), microwave (MW), or combined MW/US activation. The three modes led selectively to different annulated products: pyrazolo[3,4-d]pyrimidinone 5 was isolated in 88% yield under US, oxazinyl-pyrazolidinone 6 in 85% yield under MW, and the more extensively fused derivative 7 in 85% yield under combined MW/US conditions. These results indicate that pathway selection can be influenced by the physical manner in which energy is supplied without altering the reagent set. The products were assigned from FT-IR, NMR, EI-MS, and elemental-analysis data and were screened against representative Gram-positive and Gram-negative bacteria. Compound 5 gave the best overall antibacterial response, including a 32.0 ± 0.6 mm inhibition zone against Staphylococcus aureus and MIC values of ≤ 12.5 µg/mL. Its experimental performance was consistent with favorable docking contacts and stable molecular-dynamics behavior, while DFT/Mulliken analysis provided a rationale for the reactive sites involved in annulation and dehydration.
SN - 1612-1872
SN - 1612-1880
ER -