- Structural identification between phthalazine-1,4-diones and n-aminophthalimides via vilsmeier reaction: Nitrogen cyclization and tautomerization study
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N-aminophthalimides and phthalazine 1,4-diones were synthesized from isobenzofuran1,3-dione, isoindoline-1,3-dione, furo [3,4-b] pyrazine-5,7-dione, or 1H-pyrrolo [3,4-c] pyridine-1,3dione with monohydrate hydrazine to carry out the 5-exo or 6-endo nitrogen cyclization under the different reaction conditions. Based on the control experimental results, 6-endo thermodynamic hydrohydrazination and kinetical 5-exo cyclization reactions were individually selective formation. Subsequently, Vilsmeier amidination derivatization was successfully developed to probe the structural divergence between N-aminophthalimide 2 and phthalazine 1,4-dione 3. On the other hand, the best tautomerization of N-aminophthalimide to diazinone was also determined under acetic acid mediated solution.
- Chung, Cheng-Yen,Li, Sin-Min,Lin, Hui-Yi,Tsai, Shuo-En,Tseng, Ching-Chun,Wong, Fung Fuh
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- PYRIDAZINES CONDENSED WITH A HETERO RING, III
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The cleavage of the pyrazine ring by means of hydrazine hydrate was studied on various model compounds having the pyrazinopyridazine skeleton.The method developed makes possible the preparation of 4,5-diaminopyridazinediones (4a-c) from pyrazino2,
- Koermendy, Karoly,Ruff, Ferenc
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p. 253 - 262
(2007/10/02)
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- Heterocyclic Analogues of Phthalhydrazides: Cyclic Hydrazides of Pyridine 1-Oxide and Pyrazine 1,4-Dioxide Dicarboxylic Acids
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The synthesis of N-oxides of the cyclic hydrazides of pyridine and pyrazine o-dicarboxylic acids is described.Pyridopyridazine-5,8-dione 1-oxide, pyridopyridazine-1,4-dione 6-oxide, and pyrazinopyridazine-5,8-dione 1,2-dioxide, were obtained by direct oxidation of the parent hydrazides with peracetic acid.The pyridopyridazine derivatives were also unambiguously synthesized by treating the anhydrides or diesters of the relevant carboxylic acid 1-oxides with hydrazine hydrate.
- Paul, D. Brenton
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