A facile, practical and metal-free microwave-assisted protocol for mono- and bis-[1,2,4]triazolo[1,5- a ]pyridines synthesis utilizing 1-amino-2-imino-pyridine derivatives as versatile precursors.
| Autor: | Ibrahim HM; Chemistry Department, Faculty of Science, Fayoum University P.O. Box 63514 Fayoum Egypt hmi00@fayoum.edu.eg hamadaaldeb@yahoo.com., Behbehani H; Chemistry Department, Faculty of Science, Kuwait University P.O. Box 5969 Safat 13060 Kuwait drhaider.b@gmail.com., Ahmed Arafa WA; Chemistry Department, Faculty of Science, Fayoum University P.O. Box 63514 Fayoum Egypt hmi00@fayoum.edu.eg hamadaaldeb@yahoo.com.; Chemistry Department, College of Science, Jouf University P.O. Box 2014 Sakaka Aljouf Kingdom of Saudi Arabia. |
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| Jazyk: | angličtina |
| Zdroj: | RSC advances [RSC Adv] 2020 Apr 20; Vol. 10 (26), pp. 15554-15572. Date of Electronic Publication: 2020 Apr 20 (Print Publication: 2020). |
| DOI: | 10.1039/d0ra02256j |
| Abstrakt: | A facile and effective assembly of several substituted functionalized mono- and bis-[1,2,4]triazolo[1,5- a ]pyridines from conveniently attainable 1-amino-2-imino-pyridines has been established. Using microwave irradiation speeds up the reaction efficiently, proceeding with a higher rate and yields than with conventional heating. In the presented protocol, a broad variety of carboxylic acids could be employed effectively to synthesize the respective derivatives via direct metal-free C-N bond construction. Interestingly, other substrates such as aldehydes (or their arylidene malononitriles), phenyl isothiocyanate, glyoxalic acid, and acrylonitriles could also provide the corresponding 1,2,4-triazolo[1,5- a ]pyridines successfully. This versatile and convergent approach performs well with both deactivating and activating substrates in an environmentally benign manner compared with other already reported protocols. Other notable merits of the current strategy involve no need for column chromatography, no tedious work-up, and a direct pathway for the fast design of triazolopyridine frameworks. The identity of the newly synthesized compounds was established using several spectroscopic techniques, and X-ray single-crystal tools were employed to authenticate the suggested structures of some representative samples. Competing Interests: The authors declare that they have no competing interests. (This journal is © The Royal Society of Chemistry.) |
| Databáze: | MEDLINE |
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