- Synthesis of substituted 1 H-indazoles from arynes and hydrazones
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The 1H-indazole skeleton can be constructed by a [3 + 2] annulation approach from arynes and hydrazones. Under different reaction conditions, both N-tosylhydrazones and N-aryl/alkylhydrazones can be used to afford a variety of indazoles. The former reaction affords 3-substituted indazoles either via in situ generated diazo compounds or through an annulation/elimination process. The latter reaction leads to 1,3-disubstituted indazoles likely through an annulation/oxidation process. The reactions operate under mild conditions and can accommodate aryl, vinyl, and less satisfactorily, alkyl groups.
- Li, Pan,Wu, Chunrui,Zhao, Jingjing,Rogness, Donald C.,Shi, Feng
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experimental part
p. 3149 - 3158
(2012/07/14)
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- A novel synthesis of 1,3,5-trisubstituted pyrazoles through a spiro-pyrazoline intermediate via a tandem 1,3-dipolar cycloaddition/elimination
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The syntheses of an important class of hitherto unreported 1,3,5-pyrazoles, inspired by an unanticipated eliminatory ring opening are described. The reported pyrazole compounds were constructed through the Huisgen cyclization of 2-methylene-1,3,3-trimethy
- Dadiboyena, Sureshbabu,Valente, Edward J.,Hamme II, Ashton T.
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supporting information; experimental part
p. 291 - 294
(2009/04/14)
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