- Bicyclic Triazoles From a Diazo Transfer Reaction Between Cyclic Enaminones and 5,7-Dinitro-3-diazo-1,3-dihydro-2H-indol-2-one
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The synthetic usefulness of a new method of 1,2,3-triazole synthesis has been demonstrated.By employing cyclic enamino esters 3 and enaamino ketones 4 in reactions with 5,7-dinitro-3-diazo-1,3-dihydro-2H-indol-2-one (1), bicyclic triazoles 5 and 6 have been prepared in good to excellent yields.
- Augusti, Rodinei,Kascheres, Concetta
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- Formation of 3,3,5,7-tetranitrooxindole and 3,5,7-trinitroindazole by nitration of oxindole
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Nitration (HNO3/H2SO4) of oxindole gave 3,3,5,7-tetranitrooxindole (1c), which readily underwent ring-opening and decarboxylation to 4,6-dinitro-2-(dinitromethyl)aniline (4b), which in turn could be cyclized to 3,5,7-trinitroindazole (5).
- Bergman, Jan,Bergman, Solveig
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p. 9263 - 9266
(2007/10/03)
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- Reactions of 3-diazo-1,3-dihydro-2H-indol-2-one derivatives with enaminones. A novel synthesis of 1,2,3-triazoles
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A new and efficient method of 1,2,3-triazole synthesis is described in which these heterocyclics are formed through a novel nitrogen transfer from diazocarbonyl compounds to enaminones. Thus, the reaction of 3-diazo-1,3-dihydro-2H-indol-2-one derivatives 1 (X = NR3) and 3-diazobenzo[b]thiophen-2(3H)-one 5 (X = S) with enaminones 2 and 7 leads to the formation of mainly 1,2,3-triazoles 4 and pyrazoloquinazolinones 3. Both the phenyl substituents (Y and Z in 1) and the nature of the X group affects the reaction rate and product distribution. Rate increases with an increase in the electron withdrawing ability of the substituents Y and Z. The dinitro derivative Ig is shown to be the most efficient in promoting 1,2,3-triazole 4 formation while pyrazoloquinazolinones 3 are often competitively formed when other derivatives of 1 are employed.
- Augusti,Kascheres
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p. 7079 - 7083
(2007/10/02)
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