Access to the 2,3-dihydropyridazin-3-one and as-triazino[3,4-a]phthalazine ring systems from 4-aryl-2-oxo-butanoic acids |
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Authors: | El-Sayed H El-Ashry Adel Amer George H Labib Mohamed M Abdel Rahman Abdel Monem El-Massry |
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Abstract: | A novel series of 2,3-dihydropyridazin-3-ones 15 were synthesized via condensation between hydrazines and 4-(p-chlorophenyl)-2-hydroxy-2-(2-oxo-2-substituted ethyl)butanoic acids 8 which in turn were prepared by the reaction of substituted benzylpyruvic acids 6 with methyl alkyl(aryl) ketones 7. Dehydration of 8b-d by a mixture of glacial acetic acid and hydrochloric acid afforded 4-(p-chorophenyl)-2-(substituted phenacyl)-2-butenoic acids 10. Condensation reaction of 10 with hydrazines gave type 15 compounds in good yields. Also, a new series of as-triazino3,4-a]phthalazines 20 was obtained from the reaction of substituted benzylpyruvic acids 6 with hydralazine to give the hydralazones 19 which underwent dehydrative cyclization reaction with PPA to afford 20. Structure assignments are based on 1H, 13C nmr and ir spectra. |
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