Diversity-Oriented Synthesis of Benzo[ f ][1,4]oxazepine-, 2 H -Chromene-, and 1,2-Dihydroquinoline-Fused Polycyclic Nitrogen Heterocycles under Microwave-Assisted Conditions
An efficient, diversity-oriented synthesis of oxazepino[5,4- ]quinazolin-9-ones, 6 -chromeno[4,3- ]quinolines, and dibenzo[ , ][1,6]naphthyridines was established involving a substrate-based approach under microwave-assisted and conventional heating conditions in high yields (up to 88%). The CuBr -c...
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Veröffentlicht in: | Journal of organic chemistry 2023-07, Vol.88 (13), p.8643-8657 |
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Hauptverfasser: | , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | An efficient, diversity-oriented synthesis of oxazepino[5,4-
]quinazolin-9-ones, 6
-chromeno[4,3-
]quinolines, and dibenzo[
,
][1,6]naphthyridines was established involving a substrate-based approach under microwave-assisted and conventional heating conditions in high yields (up to 88%). The CuBr
-catalyzed, chemoselective cascade annulation of
-propargylated 2-hydroxybenzaldehydes and 2-aminobenzamides delivered oxazepino[5,4-
]quinazolin-9-ones involving a 6-
-
cyclization-air oxidation-1,3-proton shift-7-
cyclization sequence. This one-pot process showed excellent atom economy (-H
O) and constructed two new heterocyclic rings (six- and seven-membered) and three new C-N bonds in a single synthetic operation. On the other side of diversification, the reaction between
/
-propargylated 2-hydroxy/aminobenzaldehydes and 2-aminobenzyl alcohols delivered 6
-chromeno[4,3-
]quinolines and dibenzo[
,
][1,6]naphthyridines involving sequential imine formation-[4 + 2] hetero-Diels-Alder reaction-aromatization steps. The influence of microwave assistance was superior to conventional heating, where the reactions were clean, rapid, and completed in 15 min, and the conventional heating required a longer reaction time at a relatively elevated temperature. |
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ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/acs.joc.3c00552 |