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15. 4. 2003.
A Direct Conversion of 5,6,7,8-Tetrahydro-2H-1-benzopyran-2,5-diones into Substituted 1-Amino-5,6,7,8-tetrahydroquinoline-2,5-diones.
A highly selective transformation of 5,6,7,8-tetrahydro-2H-1-benzopyran-2,5-diones (1a-c) with hydrazides, arylhydrazines and heterocyclic hydrazines as nitrogen-containing nucleophiles (2) into the corresponding 1-amino-5,6,7,8-tetrahydroquinoline-2,5-diones (5-17) was investigated. The reaction was carried out in the mixture of ethanol, water and triethylamine, and the corresponding quinoline-2,5-diones were obtained in 52-89% yields. The compounds (3) and (4) were proposed to be intermediates in this transformation.