Darstellung polymerisationsfähiger 3-vinyl-pyrazole

Manecke, Georg; Schenck, Hans‐Uwe

doi:10.1016/s0040-4039(01)87764-9

Cited by 9 publications

(2 citation statements)

References 3 publications

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“…The solid residue was crystallized from chloroform to give 9a. Yield: 0.213 g (76%); mp 158-160°(from chloroform), lit [26] mp 158.0-158.5°. Ir (cm -1 ): 3250 (N-H), 1699 (C=O).…”

Section: May-jun 2003 491mentioning

confidence: 99%

Regioselective synthesis of ethyl pyrazolecarboxylates from ethyl 3‐[(dimethylamino)methylidene]pyruvate and diethyl 3‐[(dimethylamino)methylidene]‐2‐oxosuccinate. Isolation of ethyl 4,5‐dihydro‐1‐heteroaryl‐5‐hydroxy‐1H‐pyrazole‐5‐carboxylates as stable intermediates in the pyrazole ring formation

Hanzlowsky

Jelenčič

Rečnik

et al. 2003

Journal of Heterocyclic Chem

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Reactions of ethyl 3-[(E)-(dimethylamino)methylidene]pyruvate (3) and 3-[(dimethylamino)methylidene]-2-oxosuccinate (4) with hydrazine monohydrochloride (5a) and (hetero)arylhydrazines (5b-i) afforded, regioselectively, 1-substituted ethyl 1H-pyrazole-5-carboxylates 9a-f and diethyl 1H-pyrazole-3,4-dicarboxylates, 11a-i, respectively. Upon treatment of 3 with pyridazinylhydrazines 5d-f, the stable intermediates, 1-substituted ethyl 4,5-dihydro-5-hydroxy-1H-pyrazole-5-carboxylates 8d-f, were isolated. Treatment of compounds 8d-f in acetic acid under reflux furnished the pyrazoles 9d-f. On the other hand, reaction of 3 with N,N'-dimethylhydrazine (5l) gave ethyl 1-methyl-1H-pyrazole-3-carboxylate (14). The structures of compounds 3, 4, 14 were determined by nmr (noesy and hmbc techniques), while the structures of compounds 8f, 9f, and 11e,f were determined by X-ray diffraction.

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“…The solid residue was crystallized from chloroform to give 9a. Yield: 0.213 g (76%); mp 158-160°(from chloroform), lit [26] mp 158.0-158.5°. Ir (cm -1 ): 3250 (N-H), 1699 (C=O).…”

Section: May-jun 2003 491mentioning

confidence: 99%

Regioselective synthesis of ethyl pyrazolecarboxylates from ethyl 3‐[(dimethylamino)methylidene]pyruvate and diethyl 3‐[(dimethylamino)methylidene]‐2‐oxosuccinate. Isolation of ethyl 4,5‐dihydro‐1‐heteroaryl‐5‐hydroxy‐1H‐pyrazole‐5‐carboxylates as stable intermediates in the pyrazole ring formation

Hanzlowsky

Jelenčič

Rečnik

et al. 2003

Journal of Heterocyclic Chem

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“…A particular feature of both the latter reactions is that the dipolar intermediates may be trapped by addition of water or methanol to yield stable adducts (37) and (38), differing from the cycloadducts (39) and (40). (15)] have been known many years but it was not until the early 1960's that the classification 'lY3-dipolar cy~loaddition'~~, 3 5 became generally accepted.…”

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confidence: 99%

Chapter 3. Part (iii) Reaction mechanisms

Ledwith¹

1968

Annu. Rep. Prog. Chem., Sect. B

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Orbital Symmetry Correlations.-'Orbital symmetry controls in an easily discernible manner the feasibility and ,stereochemical consequences of every concerted reaction'.Conservation of orbital symmetry, as exemplified in the Woodward-Hoffman rules' for organic reactions occurring in a concerted manner, has now become an established landmark in the interpretation of reaction mechanisms. Application of Woodward-Hoffman rules to the most common types of cycloaddition, cycloelimination, electrocyclic reactions, and sigmatropic rearrangements has been further reviewed by Woodward and Hoffman,' by Volmer and S e r ~i s , ~ and more exhaustively by Gill4 and by Miller.5 The last review is particularly stimulating on two counts. It attempts to place orbital symmetry correlation in perspective with respect to the general development of theories relating to organic reaction mechanisms, and it demonstrates clearly defined correspondence between the Woodward-Hoffman approach'v ' and the more theoretical treatments of Longuet-Higgins and Abrahamson6 and Fukui.' In addition to these general review articles, application of orbital symmetry correlation to the simplest example of an electrocyclic reaction-the cyclopropyl -+ ally1 cation rearrangement-has been surveyed by DePuy.An important new application of orbital symmetry correlation has been deduced by McCapra' for some reactions displaying chemiluminescence. Previous work has demonstrated that chemiluminescence in biochemical systems results from decomposition of four-membered cyclic peroxides. McCapra' suggests that if decomposition of the peroxide is concerted then conservation of' orbital symmetry in this electrocyclic reaction ensures the formation of an excited (luminescent) state of one of the carbonyl fragments.

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Zur Orientierung der Addition von Vinyldiazomethan und Diazomethan an Acetylenderivate

Manecke

Schenck

1971

Chem. Ber.

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Diazomethan (la) und Vinyldiazomethan (1 b) werden an einseitig (2ag) und doppelseitig (2h-k) substituierte Acetylenderivate addiert. Es wird die Giiltigkeit der Orientierungsregel von $1. Auwers und Ungernach2) fur diese Additionen iiberpriift und die Abhingigkeit der Orientierung der Additionen von den Substituenten der Dreifachbindung untersucht. 1 b reagicrt iin Gegensatz zu 1 a nur mit carbonylkonjugicrten Dreifachbindungen und dabei nur jeweils in eine der beiden moglichen Additionsrichtungen. Der Strukturbeweis fur die erhaltenen Pyrazolderivate 3 -14 erfolgte NMR-spektroskopisch, fur 15~-18 mit Hilfe chemischer Methoden. Orientation of the Addition of Diazopropene and Diazomethane to Acetylenic CompoundsThe addition of diazomethane (la) and diazopropenc (1 b) to monosubstituted (2ag) and disubstituted (2h-k) acetylenic compounds is described. The validity of the orientation rule formulated by v. Acirvers and litigemachz) for these additions and the dependence of the orientation on substituents of the triple bond are examined. In contrast to l a , 1 b reacts only with carbonyl conjugated triple bonds and only in one of the two possible orientations. The structure of the isolated pyrazole derivatives 3-14 is confirmed by n.1n.r. spectroscopy and the structure of 15.-18 by chemical means.

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Darstellung polymerisationsfähiger 3-vinyl-pyrazole

Cited by 9 publications

References 3 publications

Chapter 3. Part (iii) Reaction mechanisms

Zur Orientierung der Addition von Vinyldiazomethan und Diazomethan an Acetylenderivate

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