Isomérisation thermique de vinyl-2 aziridines N-substituées

1976 ◽  
Vol 54 (10) ◽  
pp. 1590-1598 ◽  
Author(s):  
Daniel Borel ◽  
Yvonne Gelas-Mialhe ◽  
Roger Vessière
Keyword(s):  
Double Bond ◽  
Thermal Isomerization ◽  
Experimental Results ◽  
Phenyl Substituent ◽  
Ethylene Imine ◽  
Ring Carbon ◽  
Reaction Proceeds

The thermal isomerization of 2-vinylaziridines, variously substituted on the ring and the double bond, has been studied. The nature of the products formed depends on the nature of the substituents in positions 1 and 3. If the ring carbon-3 carries a phenyl substituent, the thermolysis yields, in most cases, a Δ-2-pyrroline. With unsubstituted or 3-alkylaziridines the reaction proceeds, depending on the nature of the substituent on the nitrogen, either to an ethylene imine or to a mixture of Δ-2- and Δ-3-pyrrolines. Mechanisms to interpret the experimental results are proposed. [Journal translation]

Reactions of 4-Pyrones with Azomethine Ylides as a Chemo­selective Method for the Construction of Multisubstituted Pyrano[2,3-c]pyrrolidines

Synthesis ◽  
2021 ◽  
Author(s):  
Dmitrii L. Obydennov ◽  
Vyacheslav D. Steben’kov ◽  
Konstantin L. Obydennov ◽  
Sergey A. Usachev ◽  
Vladimir S. Moshkin ◽  
...  
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Computational Studies ◽  
Carbon Double Bond ◽  
Reactivity Indexes ◽  
Reaction Proceeds

Abstract4-Pyrones bearing electron-donating and electron-withdrawing groups react with nonstabilized azomethine ylides to form pyrano[2,3-c]pyrrolidines in moderate to good yields. The reaction proceeds chemoselectively as a 1,3-dipolar cycloaddition of the azomethine ylide at the carbon–carbon double bond of the pyrone activated by the electron-withdrawing substituent. The reactivity of 4-pyrones toward azomethine ylides was rationalized by computational studies with the use of reactivity indexes. The pyrano[2,3-c]pyrrolidine moiety could be modified, for example by a ring-opening transformation under the action of hydrazine to provide pyrazolyl-substituted pyrrolidines.

Natural and Synthetic Rubber. II. Reduction of Isoprene by Na-Nh3

1929 ◽  
Vol 2 (3) ◽  
pp. 452-452
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Molecular Weight ◽  
Double Bond ◽  
Low Temperature ◽  
High Molecular Weight ◽  
Liquid Ammonia ◽  
Volatile Hydrocarbon ◽  
Hydrogen Addition ◽  
Synthetic Rubber ◽  
Reaction Proceeds ◽  
Natural And Synthetic

Abstract The reduction of isoprene by sodium in liquid ammonia was attempted to determine: (1) whether reduction would take place in preference to polymerization and (2) the location of the added hydrogen. Isoprene was added to sodium dissolved in liquid ammonia and a 60% yield of 2-methyl-2-butene resulted. No other volatile hydrocarbon was found. High molecular weight hydrocarbons were formed but were not investigated. It is thus shown: (1) that the predominant reaction proceeds in accordance with the equation C5C8+2Na+2NH3=C5C10+2NaNH2 and (2) that hydrogen adds to isoprene in the 1,4-position, in agreement with Thiele's theory. The hydrogen addition is similar to the bromination of isoprene at low temperature. If properly conducted the latter reaction stops after 2 atoms of bromine have been added to 1 molecule of isoprene; the resulting compound, 1,4-dibromo-2-methyl-2-butene, is characterized b the inactivity of its double bond toward bromine. Similarly, 2-methyl-2-butene obtained by reduction of isoprene is not reduced to isopentane by an excess of Na—NH3 reagent.

Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N′-Aromatic Bidentate Base Systems. IV. Bismuth(III) Halide/N,N′-Bidentate Ligand (1 : 1) Systems

1997 ◽  
Vol 50 (4) ◽  
pp. 309 ◽  
Author(s):  
Brian R. Davis ◽  
Mark G. Hinds
Keyword(s):  
Double Bond ◽  
Spectroscopic Studies ◽  
Bidentate Ligand ◽  
Unsaturated Ketone ◽  
Aryl Substituent ◽  
Reaction Proceeds

The generation of a number of 1,2-diarylcyclopropane-1,2-diols is reported. Reaction of these in situ with acid gives, primarily, an α,β-unsaturated ketone in which the aryl substituent attached to the double bond is that which is best able to stabilize a benzylic cation. It is proposed that the reaction proceeds by O-protonation of the cyclopropane-1,2-diol, followed by loss of water and opening of the resulting cyclopropyl cation and final deprotonation. Such initial O-protonation contrasts with the C-protonation normally observed in the acidolysis of cyclopropanols and other dialkyl- and alkylaryl-cyclopropane-1,2-diols.

Hetero-Diels-Alder Reactions of 2H-Phospholes with Allenes: Synthesis and Functionalization of 6-Methylene-1-phosphanorbornenes

2021 ◽  
Author(s):  
Keke Zhang ◽  
Qiao-Yu Zhang ◽  
Donghui Wei ◽  
Rongqiang Tian ◽  
Zheng Duan
Keyword(s):  
Double Bond ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Reaction Proceeds ◽  
High Yields

The phospha-Diels–Alder reaction between 2H-phospholes and arylallenes afford 6-methylene-1-phosphanorbornenes in high yields and excellent regioselectivity. This Diels–Alder reaction proceeds at the internal C=C double bond of allenes selectively. The DFT...

The mass spectra of Schiff bases. I. Simple fissions and rearrangements

1966 ◽  
Vol 19 (2) ◽  
pp. 251 ◽  
Author(s):  
DJ Elias ◽  
RG Gillis
Keyword(s):  
Double Bond ◽  
Electron Impact ◽  
Schiff Bases ◽  
Mass Spectra ◽  
Hydrogen Transfer ◽  
Molecular Ion ◽  
Ring Carbon ◽  
Carbon Bonds ◽  
Ring Nitrogen ◽  
Derivatives Of

Under electron impact, Schiff bases give a stable molecular ion which undergoes simple fission at the ring-nitrogen and ring-carbon bonds. Ortho substitution leads to ions derived from five-membered heterocycles. Derivatives of o-methoxy-benzaldehyde exhibit a two-hydrogen transfer with fission of the azomethine double bond to give the amine radical-ion.

Influence cinétique et chimique d'alcènes sur la pyrolyse d'alcanes: mise au point et nouveaux résultats

1985 ◽  
Vol 63 (11) ◽  
pp. 2869-2884 ◽  
Author(s):  
Francis Billaud ◽  
François Baronnet ◽  
Michel Niclause
Keyword(s):  
Free Radicals ◽  
Double Bond ◽  
Thermal Cracking ◽  
Experimental Results ◽  
Heavy Oils ◽  
Double Bonds ◽  
Thermal Reactions ◽  
Chemical Effects ◽  
General Rules ◽  
Complex Models

On the basis of previously reported, as well as new, experimental results, a review is presented of the kinetic and chemical influences of alkenes on the pyrolysis of alkanes. The results confirm that the addition of free H• atoms to the double bonds of alkenes is not sufficient to explain their inhibiting influence on the pyrolysis of alkanes. On the contrary, our results show that the processes of addition can account for the chemical effects of added alkenes on the pyrolysis of alkanes, namely, the modifications brought to the nature and the ratio of the products formed during the reaction. The results presented here confirm that the addition of alkyl free radicals to the double bond of alkenes does not lead to important chemical effects. The previously reported experimental results (pyrolysis of ethane in the presence of ethylene or propene, the pyrolysis of 2,2-dimethylbutane in the presence of propene, isobutene, or two isopentenes), completed by our new results (pyrolysis of ethane in the presence of isobutene, pyrolysis of isobutane in the presence of ethylene, of propene, of trans-2-butene, or of 2-methyl-2-butene), can lead to very simple general rules, on the basis of which it is possible to explain the results and to predict the modifications (relating to the nature of the products and to their ratios) that will result from the addition of an alkene during the pyrolysis of an alkane at a temperature of 500 °C (773 K). Aside from their fundamental aspects, these observations and their mechanistic consequences could be useful for the preparation of models for these thermal reactions, especially for the simplification of complex models. These observations also explain certain facts observed in industry and can help in solving some of the problems associated with the thermal cracking of heavy oils.

Thermal Isomerization at a C=N Double Bond: How Does the Mechanism Vary with the Substituent?

2005 ◽  
Vol 78 (10) ◽  
pp. 1851-1855 ◽  
Author(s):  
Hiroshi Yamataka ◽  
Salai Cheettu Ammal ◽  
Tsutomu Asano ◽  
Yasushi Ohga
Keyword(s):  
Double Bond ◽  
Thermal Isomerization

scholarly journals Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

2013 ◽  
Vol 9 ◽  
pp. 1630-1636 ◽  
Author(s):  
Robert J Perkins ◽  
Hai-Chao Xu ◽  
John M Campbell ◽  
Kevin D Moeller
Keyword(s):  
Carboxylic Acids ◽  
Radical Cation ◽  
Experimental Results ◽  
Double Bonds ◽  
Reaction Proceeds

Carboxylic acids have been electro-oxidatively coupled to electron-rich olefins to form lactones. Kolbe decarboxylation does not appear to be a significant competing pathway. Experimental results indicate that oxidation occurs at the olefin and that the reaction proceeds through a radical cation intermediate.

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