Über Keto‐Enol‐Gleichgewichte „<i>trans</i>‐fixierter”︁ β‐Dicarbonylverbindungen)

Eistert, Bernd; Reiss, Werner

doi:10.1002/cber.19540870115

Cited by 66 publications

(6 citation statements)

References 28 publications

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“…The reaction of arylidenenitroacetonitriles 190 with the pyrazolone 41a results in the formation of difficultly accessible 4aryl(hetaryl)-3-nitro[2,3-c]pyrazoles 191 exhibiting antiallergic properties. 123 It has been reported 68 125 Enolisation is important for the formation of the pyran ring, 7 and cyclic 1,3-dicarbonyl compounds are widely known as convenient reagents for the synthesis of fused 4H-pyrans. Thus a number of fused 4H-pyrans 197 containing a nitro group have been obtained by reactions of dimedone 25 with aryl (or hetaryl) derivatives of nitroacetonitrile 190.…”

Section: Synthesis Of Pyransmentioning

confidence: 99%

“…136 In this Section, we also present numerous examples of reactions of unsaturated nitriles with phenols, which can be regarded as completely enolysed ketones. 125 It is known that interaction of activated phenols (resorcinol, m-aminophenol, phloroglucinol) with a,b-unsaturated nitriles under the conditions of the Hoesch reaction 137 does not involve the cyano group. The phenols add to the double bond giving b-arylpropionitriles or products of their subsequent cyclisation (`anomalous Hoesch reaction' 138 ).…”

Section: Synthesis Of Pyransmentioning

confidence: 99%

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Reactions of carbonyl compounds with α,β-unsaturated nitriles as a convenient pathway to carbo- and heterocycles

Sharanin¹,

Goncharenko²,

Литвинов³

1998

Russ. Chem. Rev.

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Abstrad.We re-examine the so-called Nambu-Iona-Lasinio mechanism suggested by Song, Xu and Chin in breaking the supersymmetry in the Wess-Zumino model and show that this mechanism cannot be justified without assuming special effects behveen fermions. The fermion condensation suggested by them corresponds to an mstable vacumm configuration and as a result there is no fermion condensation and no supersymmetg breaking in the model they discuss.

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Section: Synthesis Of Pyransmentioning

confidence: 99%

Section: Synthesis Of Pyransmentioning

confidence: 99%

Reactions of carbonyl compounds with α,β-unsaturated nitriles as a convenient pathway to carbo- and heterocycles

Sharanin¹,

Goncharenko²,

Литвинов³

1998

Russ. Chem. Rev.

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“…The reactions of benzhydrol with ethyl acetoacetate (12) and acetylacetone (14) gave the expected β-dicarbonyl compounds (17) and (19) as the final products, [11] and Meldrum's acid (11) gave 3,3-diphenylpropanoic acid (16), almost certainly formed by hydrolysis and decarboxylation of the dioxanedione initially formed by C-alkylation of the enol (this type of formolysis and decarboxylation has been reported for other β-diesters [12] ). Surprisingly, however, neither diethyl malonate, nor ethyl cyanoacetate, nor malononitrile gave any C-alkylation products (which we had expected by analogy with, for example, the reactions of these active methylene compounds in the Knoevenagel and Claisen-Schmidt condensations.…”

Section: Oh Phmentioning

confidence: 64%

“…These results indicate that there is an apparent threshold enol content for the C-alkylation reaction to occur, but the nature of the correlation between isolated yield and reaction time is not straightforward. The equilibrium enol contents of the active methylene compounds in C-alkylation (12) 8.0-13.2 [20] C-alkylation (13) 0.25 [20] Ritter reaction (14) 76.4 [20] C-alkylation protic solvents are gathered in Table 2; only those compounds with significant equilibrium enol content gave C-alkylation products.…”

Section: Oh Phmentioning

confidence: 99%

Reactions of Active Methylene Compounds with Benzhydrol During Solvolysis in Formic Acid

Gullickson¹,

Lewis²

2003

Aust. J. Chem.

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Formic acid reacts with benzhydrol to give benzhydryl formate, which reacts with active methylene compounds in refluxing formic acid to give either C-alkylation or Ritter reaction products. The product formed is determined by the equilibrium enol content of the active methylene compound. These reaction conditions avoid the use of halogenated reaction solvents, and the pure products are isolated without recourse to chromatography.

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“…26 Thus, the condensation of the activated phenol resorcinol led to the formation of 8´ R 2 amino 7 hydroxy 4´,4´,6´ trimethyl 2´ oxo 4´H spiro[chromene 4,1´ pyrrolo [3,2,1 ij]quinoline] 3 carbonitriles 11a,b, but rather in low yields. The reaction time increased to 40 min.…”

mentioning

confidence: 99%

Efficient methods for the synthesis of spiroheterocyclic systems based on 4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinoline-1,2-diones

2014

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Cyclocondensation of 4H pyrrolo[3,2,1 ij]quinoline 1,2 diones with some 1,2 and 1,3 di nucleophiles, their three component cyclocondensations with arylamines and 2 mercapto acetic acid, as well as with malononitrile and various methylene active carbonyl compounds lead to new heterocyclic systems: spiro [imidazolidine 2,1´ pyrrolo[3,2,1 ij]quinoline], spiro[1,3 dioxolane 2,1´ pyrrolo[3,2,1 ij]quinoline], spiro[1,3 benzothiazole 2,1´ pyrro lo[3,2,1 ij]quinoline], spiro[ carboline 1,1´ pyrrolo[3,2,1 ij]quinoline], spiro[3,1 benzox azine 2,1´ pyrrolo[3,2,1 ij]quinoline], spiro[pyrrolo[3,2,1 ij]quinoline 1,2´ quinazoline], spiro[pyrrolo[3,2,1 ij]quinoline 1,2´ [1,3]thiazolidine], spiro[pyran 4,1´ pyrrolo[3,2,1 ij] quinoline], spiro[chromene 4,1´ pyrrolo[3,2,1 ij]quinoline], spiro[pyrano[4,3 b]pyran 4,1´ pyrrolo[3,2,1 ij]quinoline], spiro[pyrano[3,2 c]chromene 4,1´ pyrrolo[3,2,1 ij]quinoline], and spiro[pyrano[2,3 c]pyrazole 4,1´ pyrrolo[3,2,1 ij]quinoline].An interest to substituted 4H pyrrolo[3,2,1 ij]quino line 1,2 diones 1,2 is explained not only by the presence in their structure of two biologically active fragments, the hydroquinoline and the indole ones, but also by the pres ence of highly active pyrroledione ring, which opens the way to the preparation of poorly available derivatives of this heterocyclic system. Earlier, 3 these compounds, as well as indole 2,3 dione (isatin), were involved in the condensation reaction with a number of N and C nu cleophiles with the formation of linear derivatives of in dolin 2 one. However, more valuable are structural ana logs of oxindole alkaloids, in which the indolinone frag ment forms a spiro system with five and six mem bered heterocycles. 4,5 Such compounds are frequently encountered with not only among natural compounds, but also among medicinal agents, since the spirohetero cycles have a rigid spatial structure, that increases poten tial possibilities of their binding with biotargets (enzymes, receptors, ionic channels). 6-9 In this connection, it was interesting to use 4,4,6 trimethyl 4H pyrrolo[3,2,1 ij] quinoline 1,2 diones 1 in the cyclocondensation reac tions at a  carbonyl (with respect to the nitrogen atom) group with the formation of spiro derivatives. The purpose of the present work is the development of efficient meth ods for the synthesis of spiroheterocyclic systems based on 4,4,6 trimethyl 4H pyrrolo[3,2,1 ij]quinoline 1,2 diones.The literature data on chemistry of isatin 10,11 show that one of the approaches to a direct synthesis of 3 spiroindolin 2 ones by the reaction of isatin with dinu cleophilic agents has some restrictions. For example, the attack of such dinucleophiles as o phenylenediamine and o amino(thio)phenol can be directed not only on the  carbonyl group, but also on the  carbonyl one; besides, the indole ring can undergo the opening reaction. 12-20 The chemoselectivity of the process depends on the nature and amount of the agent, solvent, and temperature, as well as on the presence and the character of substituents in the starting isat...

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Über Keto‐Enol‐Gleichgewichte „trans‐fixierter”︁ β‐Dicarbonylverbindungen)

Cited by 66 publications

References 28 publications

Reactions of carbonyl compounds with α,β-unsaturated nitriles as a convenient pathway to carbo- and heterocycles

Reactions of carbonyl compounds with α,β-unsaturated nitriles as a convenient pathway to carbo- and heterocycles

Reactions of Active Methylene Compounds with Benzhydrol During Solvolysis in Formic Acid

Efficient methods for the synthesis of spiroheterocyclic systems based on 4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinoline-1,2-diones

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