- Synthesis and Reactions of 2-Arylhydrazinotropones. I. Preparation of 2-(2-Arylhydrazino)tropones and the 4-Substituted Derivatives
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A wide variety of 2-(2-arylhydrazino)tropones were prepared by the reactions of 2-tosyloxytropone with arylhydrazines.The dimeric compounds 6,6'-bis(arylhydrazono)-1,1'-bi(2,4-cycloheptadiene)-7,7'-diones, 2-anilinotropones, and 3-(2-arylhydrazino)tropones were isolated as minor products in some cases.Similarly, starting with 2-tosyloxytropones bearing an isopropyl, isopropenyl, (1-acetamidoethyl), and protected acetyl group at the 5-position, 4-substituted 2-(2-arylhydrazino)tropones were obtained as the major products by the abnormal substitution reaction.These 2-(2-arylhydrazino)tropones are expected to effectively serve as precursor for a convenient synthesis of 5-aryl-substituted tropolones via benzidine-type rearrangement. 1H NMR (200 or 500-MHz) parameters for these 4-substituted 2-(2-arylhydrazino)tropones are given for their unambiguous structural assignments.
- Nozoe, Tetsuo,Imafuku, Kimiaki,Yin, Bing-Zhu,Honda, Masaaki,Goto, Yasutomo,et al.
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p. 2531 - 2540
(2007/10/02)
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- A Convenient Synthesis of 5-Aryltropolones via Novel Benzidine Type Rearrangement of 2-(2-Arylhydrazino)tropones
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Treatment of a wide variety of 2-(2-arylhydrazino)tropones with ethanolic acid at 50-80 deg C readily gave the benzidine type rearrangement products, i.e. 2-amino-5-(4-aminoaryl)tropones, which in turn were conveniently led to the corresponding 5-aryltropolones that can be utilized for synthesizing B-ring-open analogues of colchicine.
- Nozoe, Tetsuo,Takase, Kahei,Saito, Hiroaki,Yamamoto, Hiroshi,Imafuku, Kimiaki
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p. 1577 - 1580
(2007/10/02)
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