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PdCl 2 ‐Catalyzed Oxidative Cyclization of N ‐(2’‐Alkynylaryl)‐1,3‐ketoamides: Synthesis of 3,4‐Diacyl‐2‐Quinolones
Author(s) -
Punjajom Kunlayanee,
Tummatorn Jumreang,
Ruchirawat Somsak,
Thongsornkleeb Charnsak
Publication year - 2021
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202100035
Subject(s) - chemistry , ceric ammonium nitrate , catalysis , quinolone , adduct , yield (engineering) , combinatorial chemistry , medicinal chemistry , organic chemistry , biochemistry , polymer , materials science , metallurgy , grafting , antibiotics
3,4‐Diacyl‐2‐quinolone derivatives were prepared in a rapid manner starting from N ‐(2’‐alkynylaryl)‐1,3‐ketoamide substrates. The reaction showcased a mild radical process mediated by ceric ammonium nitrate (CAN) in the presence of 5 mol% PdCl 2 under basic conditions and was applicable to a wide range of substrates, giving 3,4‐diacyl‐2‐quinolone products in up to 91% yield in over 40 examples. The reaction proceeded via the generation of a radical intermediate which could be trapped as a TEMPO‐adduct that was isolated and fully characterized. The reported method provided a practical and scalable synthetic access to densely functionalized 3,4‐diacyl‐2‐quinolone derivatives which would be suitable for further applications including medicinal and bioactivity evaluations as well as synthetic transformations.