Banda BP, Medishetti N, Nanubolu JB, Atmakur K. One-pot domino synthesis of five- and six-membered fused dihydropyridines promoted by PPh
3-NBS in aqueous medium.
Org Biomol Chem 2023;
21:4434-4439. [PMID:
37183547 DOI:
10.1039/d3ob00472d]
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Abstract
A facile one-pot synthesis of five- and six-membered fused dihydropyridines such as chromenodihydropyridines, pyrazolodihydropyridines and isoxazolopyridines was accomplished for the first time by employing PPh3-NBS via a formal [3 + 2 + 1] cycloaddition of 1,3-bisnucleophiles (i.e., 2-aminochromone, 4-aminochromone, 5-aminopyrazole and 5-aminoisoxazole), β-enaminones and aldehydes in aqueous medium. The present approach involves a Michael type addition followed by intramolecular cyclization leading to the formation of two new C-C bonds and one C-N bond. High compatibility and excellent yields are the advantages of this protocol.
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