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■ Transformations of 3-(1-Aminoethylidene)-5,6,7,8-tetrafluorobenzopyran-2,4-dione with Hydrazines

Konstantin V. Shcherbakov, Yanina V. Burgart, and Victor I. Saloutin*

*I. Ya. Postovski Institute of Organic Synthesis of Urals Division of Russian Academy of Sciences, 22/20, S. Kovalevskoi / Akademicheskaya Str., Ekaterinburg, GSP-147, 620041 Russia

Abstract

3-(1-Aminoethylidene)-5,6,7,8-tetrafluorobenzopyran-2,4-dione reacts with the substituted hydrazines depending on hydrazine nucleophilicity and the reaction conditions. 3-R-hydrazinoethylidene-5,6,7,8-tetrafluorobenzopyrandiones are formed as a result of the transamination at aminoethylidene fragment by hydrazine NH₂-group. In the case of methylhydrazine and hydrazine the transamination can be accompanied by the substitution of fluorine atom at the atom C-7. Benzopyrano[2,3-c]pyrazolone derivatives are produced due to the intramolecular addition of the RNH-group at the C-2 atom followed by the intramolecular substitution of fluorine atom by hydroxyl group.