Oxidation of 4-phenyl-1,2-diaminoimidazole with manganese dioxide

Hisada, Ryuki; Nakajima, Masayuki; Anselme, J.‐P.

doi:10.1016/s0040-4039(00)77959-7

Cited by 11 publications

(1 citation statement)

References 4 publications

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“…29 Similar reactivity was observed upon MnO 2 oxidation of aryl 1,2-diaminoimidazoles 20a-e (Scheme 6). The resultant cyanoimine intermediates underwent further rearrangement to give a mixture of triazoles 21a-e and regioisomeric triazines 22a-e. 30,31 Changing from a nitrene to carbene functionality in the a position does not give rise to any ring opened products, but rather resulted in solvent incorporation at the carbene. [32][33][34] Even in cases where there was no carbene trap (i.e., hexafluorobenzene as the solvent) no products derived from ring opening were detected.…”

Section: Triazolesmentioning

confidence: 99%

Reactions in the conjugated ‘ene–ene–yne’ manifold: five-membered ring fragmentation and ring formation via coarctate/pseudocoarctate mechanisms

2008

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The fragmentation of a 5-membered heteroaromatic ring to afford a conjugated ene-ene-yne skeleton, and the corresponding reverse process, cyclization of the hetero-ene-ene-yne motif to generate a variety of heterocyclic systems, are the subject of this review. These synthetically useful reactions, which proceed through a coarctate/pseudocoarctate mechanistic pathway, are unique in that they involve the generation of either a carbene or nitrene intermediate, and provide access to hard to obtain heterocyclic or ene-ene-yne structures. While fragmentation of heteroaromatic rings containing a exocyclic carbene or nitrene has been well documented in the literature for over 40 years, the use of hetero-ene-ene-yne precursors to synthesize heterocycles is a relatively new approach that is generating much interest in the literature. This review highlights both the synthetic and mechanistic aspects of these unique reactions.

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Section: Triazolesmentioning

confidence: 99%

Reactions in the conjugated ‘ene–ene–yne’ manifold: five-membered ring fragmentation and ring formation via coarctate/pseudocoarctate mechanisms

2008

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Ordnungsprinzip komplexer Reaktionen und Theorie eingeschnürter Übergangszustände

Herges

1994

Angewandte Chemie

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Bei den meisten konzertierten Reaktio-schriebene Klasse von Reaktionen, bei physikalisches Prinzip zuriickfiihren. nen wird zwischen zwei Atomen nur je-denen jeweils zwei Bindungen zwischen Das theoretische Verstindnis ermoglicht weils eine Bindung gebrochen oder ge-zwei Zentren gleichzeitig gekniipft oder nicht nur die Vorhersage des Mechaniskniipft. Geschieht dies in alternierender gebrochen werden. Die zunachst rein mus und der Stereochemie, die Theorie cyclischer Folge, so nennt man die Re-deskriptiven, aber aufralligen formalen eignet sich auch zum Ordnen der beaktionen pericyclisch. Es gibt allerdings Gemeinsamkeiten dieser Reaktionen kannten und zur Vorhersage neuer Reeine bislang nie zusammenhangend be-lassen sich auch auf ein gemeinsames aktionen dieses Typs.

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Organizing Principle of Complex Reactions and Theory of Coarctate Transition States

Herges

1994

Angew. Chem. Int. Ed. Engl.

105

100

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The majority of concerted reactions proceeds by a simultaneous breaking and making of only one bond at each atom involved in the reaction. If this process follows an alternating cyclic sequence, the reactions are called pericyclic. However, there is a hitherto never consistently characterized class of reactions that proceeds by breaking and making two bonds at one or more atoms at a time. The striking relationships that are purely descriptive and formal in the first instance are explained by a common physical principle. Theoretical insight not only permits predictions of mechanisms and stereochemistry; the qualitative theory is also used as an organizing principle for the known reactions and as a tool for predicting unprecedented reactions of this type.

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Oxidation of 4-phenyl-1,2-diaminoimidazole with manganese dioxide

Cited by 11 publications

References 4 publications

Reactions in the conjugated ‘ene–ene–yne’ manifold: five-membered ring fragmentation and ring formation via coarctate/pseudocoarctate mechanisms

Reactions in the conjugated ‘ene–ene–yne’ manifold: five-membered ring fragmentation and ring formation via coarctate/pseudocoarctate mechanisms

Ordnungsprinzip komplexer Reaktionen und Theorie eingeschnürter Übergangszustände

Organizing Principle of Complex Reactions and Theory of Coarctate Transition States

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