Novel ring contraction of 3-hydroxy-2,4(1H,3H)-quinolinediones in aqueous alkali. The first convenient route to 2-hydroxyindoxyls.
Ring contraction of 3-hydroxy-2,4(1H,3H)-quinolinediones (1) in aqueous potassium hydroxide resulted in the formation of 2-hydroxyindoxyls and/or dioxindoles. The choice of N-substituent and the reaction conditions govern the chemoselectivity of the reaction. N-Phenyl-substituted derivatives 1 give 2-hydroxyindoxyls, while N-alkyl- and N-benzyl-substituted derivatives afford the corresponding dioxindols. On the basis of byproduct analysis, as well as independent experiments, the most plausible reaction mechanism is proposed.
Kafka
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S
Faculty of Technology, Tomas Bata University, 762 72 Zlín, Czech Republic.
Klásek
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A
Kosmrlj
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J
D000468:Alkalies / Q000737:chemistry; D001685:Biological Factors / Q000138:chemical synthesis; D007211:Indoles / Q000138:chemical synthesis*; D011804:Quinolines / Q000138:chemical synthesis*; D014867:Water / Q000737:chemistry
D000468:Alkalies; D001685:Biological Factors; D007211:Indoles; D011804:Quinolines; D014867:Water; C034082:indoxyl