1.3‐Dipolare Cycloadditionen, XLVII. Reaktionen heteroaromatischer Aminoxide mit Carbonestern der Äthylen‐ und Acetylenreihe

Huisgen, Rolf; Seidl, Hildegard; Wulff, Jochen

doi:10.1002/cber.19691020325

Cited by 32 publications

(12 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Huisgen and coworkers have shown that phenanthridine N-oxide and ethyl acrylate react in DMF solution at 75° to give products of type 6 [10]. The formation of the latter has been rationalized by a [2+3] cycloaddition, followed by a spontaneous ring opening of the intermediate isoxazolidine.…”

Section: Methodsmentioning

confidence: 99%

“…occurs regioselectively, leading to 3-hydroxypropanoate, which is a product of the spontaneous ring-opening of the five-membered cycloadduct. It is worth mentioning that the structures of the isolated hydroxyesters 7 do not correspond with those of products of analogous reactions with isoquinoline and quinoline N-oxides, respectively [9][10][11]. The catalyst used in the reaction accelerates the dehydration of the hydroxyester, formed after ring opening of the initial isoxazolidine derivative.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Unexpected Course of the Reaction of 2‐Unsubstituted 1H‐Imidazole 3‐Oxides with Ethyl Acrylate

Mlostoń

Urbaniak

Wojciechowska

et al. 2012

Helvetica Chimica Acta

View full text Add to dashboard Cite

The attempted ethenylation at C(2) of 2-unsubstituted 1H-imidazole N-oxides with ethyl acrylate (= prop-2-enoate) in the presence of Pd(OAc)2 does not occur. In contrast to the other aromatic N-oxides, the [2+3] cycloaddition of imidazole N-oxides predominates, and 3-hydroxyacrylates, isomeric with the cycloadducts, are key products for the subsequent reaction. The final products were identified as dehydrated 2+1 adducts of 1H-imidazole N-oxide and ethyl acrylate. The role of the catalyst is limited to the dehydration of the intermediate 3-hydroxypropanoates to give 1H-imidazol-2-yl-substituted acrylates.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Unexpected Course of the Reaction of 2‐Unsubstituted 1H‐Imidazole 3‐Oxides with Ethyl Acrylate

Mlostoń

Urbaniak

Wojciechowska

et al. 2012

Helvetica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…Reactions of azine N-oxides with acrylates [53,54] and acrylonitriles [55] have been attempted already since the 1960s. These reactions led to 3-(2-hetroaryl)-2-hydroxy derivatives of propionic acids, formed via dipolar cycloaddition and the Scheme 6 An updated mechanism for the reaction between pyridine N-oxides and benzyne [47] cycloadduct ring opening (Scheme 7).…”

Section: Cycloaddition To Carbon-carbon Multiple Bondsmentioning

confidence: 99%

Recent Advances in Cycloaddition Reactions of Heterocyclic N-Oxides

Loska

2017

Topics in Heterocyclic Chemistry

View full text Add to dashboard Cite

1,3-Dipolar cycloaddition of N-oxides of azines and azoles has become a reliable and versatile synthetic method of preparation of highly functionalized nitrogen heterocycles. Mechanisms of cycloaddition of N-oxides are outlined, including various reaction pathways available for the initial five-membered cycloadducts. Cycloaddition to multiple carbon-carbon, carbon-nitrogen, and carbon-sulfur bonds is discussed, with particular emphasis on modern methods of selective C-2-functionalization of the heteroaromatic ring.

show abstract

“…Tautomerism of Methyl Isoquinoline-1-acetate (14). Several groups (ours included) have reported on the methyl and ethyl isoquinoline-1-acetates [17] [18]. However, two special features remained unnoticed: the facile H/D exchange of the CH 2 protons of 14 in neutral MeOD and the yellow color of its solution (l max 394 nm, e 402, EtOH).…”

mentioning

confidence: 99%

The Astounding Chemistry of a 2-Amino-1,2-dihydroisoquinoline Derivative

Durst

Finke

Huisgen

et al. 2000

HCA

Self Cite

View full text Add to dashboard Cite

Dedicated to Professor Albert Eschenmoser on the occasion of his 75th birthday The cycloadducts of isoquinolinium N-phenyl imide 2 with CC bonds are derivatives of 2-amino-1,2-dihydroisoquinoline. Their N b -vinylphenylhydrazine system is amenable to an acid-catalyzed [3,3]-sigmatropic shift; the formation of pentacyclic aminals is exemplified by 6 3 8. The dimethyl maleate adduct 11, C 21 H 20 N 2 O 4 , is exceptional by being converted on treatment with acid to bright-yellow crystals, C 24 H 22 N 2 O 6 (additional C 3 H 2 O 2 ). X-Ray crystal-structure analysis and NMR spectra reveal structure 13, and mechanistic studies indicated an initial b-elimination at the NÀN bond of 11 to yield 18; this step is followed by a retro-Mannichtype cleavage that gives methyl isoquinoline-1-acetate (14) and methyl 2-(phenylimino)acetate (15), according to the sequence C 21 H 20 N 2 O 4 (11) 3 18 3 C 12 H 11 NO 2 (14) C 9 H 9 NO 2 (15). In the second act of the drama, electrophilic attack by 15-H on the ene-hydrazine group of a second molecule of 11 furnishes 13 by a polystep intramolecular redox reaction. All rate constants must be fine-tuned in this reaction cascade to give 13 in yields of up to 78% with an overall stoichiometry: 2 C 21 H 20 N 2 O 4 (11) 3 C 24 H 22 N 2 O 6 (13) C 12 H 11 NO 2 (14) aniline. Interception and model experiments confirmed the above pathway. A by-product, C 33 H 31 N 3 O 6 (62), arises from an acid-catalyzed dimerization of 11 and subsequent elimination of 15.

show abstract

1.3‐Dipolare Cycloadditionen, XLVII. Reaktionen heteroaromatischer Aminoxide mit Carbonestern der Äthylen‐ und Acetylenreihe

Cited by 32 publications

References 15 publications

Unexpected Course of the Reaction of 2‐Unsubstituted 1H‐Imidazole 3‐Oxides with Ethyl Acrylate

Unexpected Course of the Reaction of 2‐Unsubstituted 1H‐Imidazole 3‐Oxides with Ethyl Acrylate

Recent Advances in Cycloaddition Reactions of Heterocyclic N-Oxides

The Astounding Chemistry of a 2-Amino-1,2-dihydroisoquinoline Derivative

Contact Info

Product

Resources

About