Reactions of 4-hydroxy-5,6,7,8-tetrafluorocoumarin derivatives with S-nucleophiles

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• 作者：Bazyl&prime ; I.T. ; Kisil&prime ; S.P. ; Burgart ; Ya.V. ; Saloutin ; V.I.
• 关键词：Fluorocoumarin ; Fluorochromone ; S-nucleophile ; o-Aminothiophenol ; 2-Mercaptoethanol ; Displacement ; Opening of cycle ; Acid splitting ; Cyclization ; Acyl-lactone rearrangement
• 刊名：Journal of Fluorine Chemistry
• 出版年：2000
• 出版时间：April 3, 2000
• 年：2000
• 卷：103
• 期：1
• 页码：3-12
• 全文大小：269 K

文摘

In the reactions with o-aminothiophenol, 4-hydroxy-(3-(imino)acetyl)-5,6,7,8-tetrafluorocoumarins give products of S-substitution at the C-7 atom. 7-Substituted 5,6,8-trifluorocoumarins form benzothiazole as a result of heterocyclic ring opening; 3-ethoxycarbonyl-2-methyl-5,6,7,8-tetrafluorochromone undergoes acid splitting to 2-(2-hydroxy-3,4,5,6-tetrafluorophenyl)benzothiazole. Under alkaline conditions, S-substituted coumarins decompose to acetophenone. In an acid medium, 4-hydroxy-3-iminoacetyl-5,6,8-trifluoro-7-(2-aminophenylthio)coumarin affords 7-(2-aminophenylthio)-2-methyl-5,6,8-trifluorochromone. 4-Hydroxy-5,6-difluoro-2-H-pyrano[6,5-a]phenothiazin-2-one was isolated from condensation of 7-(2-aminophenylthio)-4-hydroxy-5,6,8-trifluorocoumarin in the presence of NaH.

Reactions of 3-acetyl(iminoacetyl)-4-hydroxy-5,6,7,8-tetrafluorocoumarins and 3-ethoxycarbonyl-2-methyl-5,6,7,8-tetrafluorochromone with 2-mercaptoethanol result in the formation of 5,7,8-trisubstituted derivatives. Interaction of 3-ethoxycarbonyl-2-methyl-5,6,7,8-tetrafluorochromone with 2-mercaptoethanol, mercaptoacetic acid and 1,2-ethanedithiol leads to the formation of the 7-substituted products. Acyl-lactone rearrangement of mono- and trisubstituted chromones gives the corresponding coumarins.