Reaktionsverhalten von β-Oxo-carbonsäurederivaten der Anthracenreihe bei der Synthese von Pyrazolen / On the Reaction Behavior of ß-Oxo Carbonic Acid Derivatives of the Anthracene Series in Pyrazole Synthesis
ß-Oxo-1 and 9-anthracenepropionate (6 and 7) reacts with DMF-acetale to enaminones 10 and 11. The reaction of 2-(dimethylamino)methylen-substituted ß-oxo-1 -anthracenepropionate (10) with hydrazines yields 5-(l-anthracenyl)-pyrazol-4-carboxylates (13). In contrast, the cyclocondensation of 3-(9-anth...
| Published in: | Zeitschrift für Naturforschung B |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Walter de Gruyter GmbH
1999
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1515/znb-1999-0908 https://www.degruyter.com/view/journals/znb/54/9/article-p1133.xml https://www.degruyter.com/document/doi/10.1515/znb-1999-0908/xml https://www.degruyter.com/document/doi/10.1515/znb-1999-0908/pdf |
| Summary: | ß-Oxo-1 and 9-anthracenepropionate (6 and 7) reacts with DMF-acetale to enaminones 10 and 11. The reaction of 2-(dimethylamino)methylen-substituted ß-oxo-1 -anthracenepropionate (10) with hydrazines yields 5-(l-anthracenyl)-pyrazol-4-carboxylates (13). In contrast, the cyclocondensation of 3-(9-anthracenyl)-2-(dimethylamino)methylen-3-oxo-propionate (11) with hydrazine hydrochlorides gives 4-(9-anthracenoyl)-5-hydroxy-pyrazoles (14). This is caused by the sterical hindrance of the carbonyl group of the anthracene derivatives in position 9; thus, the cyclocondensation proceeds via reaction of the ester group of the enaminone 11. |
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