scholarly journals Nickel-catalyzed annulations of ortho-haloarylimines

2021 ◽  
Author(s):  
Srinivas Kolluru ◽  
Manvendra Singh ◽  
Bryce Gaskins ◽  
Zarko Boskovic
Keyword(s):  
Activation Energy ◽  
Secondary Amine ◽  
Oxidative Addition ◽  
Reaction Conditions ◽  
Quantitative Manner

Abstract We report the discovery, development, and mechanism of a nickel-catalyzed annulation reaction between o-haloarylimines and electron-poor olefins. The reaction produces two adjacent anti stereocenters and a free secondary amine. Spirocycles are formed from cyclic imines. We characterized the key oxidative addition intermediate and identified a major path leading to competing homo-coupling products. The activation energy of oxidative addition, and the rate of oxidative addition complex isomerization were determined. Sensitivity of the reaction to reaction conditions was established in a quantitative manner and both the scope and limitations of the method are presented.

Kinetic Model of the 1,2-Propanediol Oxidation Reaction in the Presence of 3wt%Pd/α-Al2O3 Catalyst

2021 ◽  
Vol 903 ◽  
pp. 143-148
Author(s):  
Svetlana Cornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Kinetic Model ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Oxidation Reaction ◽  
Main Product ◽  
Oxidation Process ◽  
Water Solution ◽  
Reaction Conditions

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

scholarly journals Direct Base-Assisted C‒H Cyclonickelation of 6-Phenyl-2,2′-bipyridine

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 997
Author(s):  
Nicolas Vogt ◽  
Vasily Sivchik ◽  
Aaron Sandleben ◽  
Gerald Hörner ◽  
Axel Klein
Keyword(s):  
Elevated Temperature ◽  
Title Compound ◽  
Noble Metals ◽  
Oxidative Addition ◽  
Base Metals ◽  
Base Pairs ◽  
Reaction Conditions ◽  
Wide Range ◽  
The World ◽  
First Time

The organonickel complexes [Ni(Phbpy)X] (X = Br, OAc, CN) were obtained for the first time in a direct base-assisted arene C(sp2)–H cyclometalation reaction from the rather unreactive precursor materials NiX2 and HPhbpy (6-phenyl-2,2′-bipyridine) or from the versatile precursor [Ni(HPhbpy)Br2]2. Different from previously necessary C‒Br oxidative addition at Ni(0), an extended scan of reaction conditions allowed quantitative access to the title compound from Ni(II) on synthetically useful timescales through base-assisted C‒H activation in nonpolar media at elevated temperature. Optimisation of the reaction conditions (various bases, solvents, methods) identified 1:2 mixtures of acetate and carbonate as unrivalled synergetic base pairs in the optimum protocol that holds promise as a readily usable and easily tuneable access to a wide range of direct nickelation products. While for the base-assisted C‒H metalation of the noble metals Ru, Ir, Rh, or Pd, this acetate/carbonate method has been established for a few years, our study represents the leap into the world of the base metals of the 3d series.

Organophosphorus compounds. XVI. 2-(N-Dialkylamino)alkyldiphenylphosphines, phosphine oxides and sulphides as analogues of methadone

1974 ◽  
Vol 27 (11) ◽  
pp. 2365 ◽  
Author(s):  
DJ Collins ◽  
S Mollard ◽  
N Rose ◽  
JM Swan
Keyword(s):  
Analgesic Activity ◽  
Secondary Amine ◽  
Organophosphorus Compounds ◽  
Phosphine Oxides ◽  
Reaction Conditions ◽  
Diphenylvinylphosphine Oxide

A series of 2-(N-dialkylamino)ethyldiphenylphosphine oxides and sulphides was prepared by the addition of a secondary amine to diphenylvinylphosphine oxide, or the phosphine sulphide, respectively. Similarly, a series of 2-(N-dialkylamino)propyldiphenylphosphine oxides was prepared from diphenylprop-1-enylphosphine oxide, or from diphenylprop-2-enylphosphine oxide which isomerized under the reaction conditions. Reduction of the 2-(N-dialkylamino)propyldiphenylphosphine oxides with trichlorosilane, and oxidation of the phosphines with sulphur, afforded the corresponding phosphine sulphides. ��� None of the compounds showed significant analgesic activity.

Ethylation of Ethylbenzene with Ethanol over Mordenite-Based Catalysts: Effects of Acidity, Desilication and Kinetics Analysis

2014 ◽  
Vol 12 (1) ◽  
pp. 487-496 ◽  
Author(s):  
Mohammad M. Hossain ◽  
Mogahid Osman ◽  
Sulaiman Al-Khattaf
Keyword(s):  
Activation Energy ◽  
Pore Size ◽  
Main Product ◽  
Equimolar Amount ◽  
The Other ◽  
Kinetics Analysis ◽  
High Activation ◽  
Reaction Conditions ◽  
Large Pore ◽  
Large Pore Size

Abstract This communication reports the kinetics analysis of ethylation of ethylbenzene (EB) with ethanol over large pore size mordenite catalysts. In this regard, two different catalyst samples are selected with SiO2/Al2O3 = 180 and 21, respectively. The higher acidic sample (SiO2/Al2O3 = 21) is desilicated to study the effects of desilication on the EB ethylation. The EB ethylation experiments are conducted in a fluidized CREC Riser Simulator using equimolar amount of EB and ethanol as feed. Under the studied reaction conditions, diethylbenzene (DEB) is the main product while a small amount of benzene and lighter gases are also produced. In addition to DEB, the higher acidic mordenite sample also produces benzene via dealkylation of EB. On the other hand, the large pore size mordenite sample gives triethylbenzene (TEB) as a secondary alkylation product. The desilicated sample shows slightly higher DEB selectivity but the EB conversion with this sample is low. Power law–based kinetics evaluation also confirms the above observations by showing low activation energy for DEB formation while high activation energies for benzene and TEB formations.

Thermal Routes to Substituted Cyclopentadienes

1972 ◽  
Vol 50 (19) ◽  
pp. 3186-3195 ◽  
Author(s):  
D. M. Findlay ◽  
Marie Lessard Roy ◽  
Stewart McLean
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Thermal Process ◽  
Kinetic Studies ◽  
Alder Reaction ◽  
Diels Alder ◽  
Reaction Conditions ◽  
Phenyl Azide ◽  
Aromatic Fragment ◽  
Diels Alder Reaction

An investigation has been made with the aim of finding a route to cyclopentadienes, particularly those with a single substituent at the 5-position, in which the final step is a thermal process of low enough activation energy that the cyclopentadiene produced does not undergo rearrangement by hydrogen migration under the reaction conditions. In the routes studied the final intermediates have been suitably substituted norbornenes which can lead to the required cyclopentadiene and an aromatic fragment by a retro-Diels–Alder reaction. In one series the intermediate was a phenyl azide adduct of norbornadiene which fragmented to cyclopentadiene and phenyltriazole, but the temperature required for this was clearly too high to allow substituted cyclopentadienes to be isolated before they had rearranged. In the course of this work, in addition to the exo-adduct of phenyl azide, the endo-adduct and a number of bisadducts were obtained and studied. In another series, adducts of tetraphenylcyclopentadienone and dimethyldiphenylcyclopentadienone with norbornadiene and 7-phenylnorbornadiene were prepared and studied. Decarbonylation of the adducts was effected both thermally and photochemically; in the latter case the reaction could be carried out at low temperature and the dihydrobenzene (a dihydrobenzonorbornadiene) produced was isolable. With or without isolation, the dihydrobenzene underwent a subsequent retro-Diels–Alder reaction to provide the cyclopentadiene and a substituted benzene. Kinetic studies showed that the activation energy for this process was almost but not quite low enough to satisfy the conditions stipulated, and in no case was a 5-substituted cyclopentadiene isolated before it had rearranged.

Catalyst-free Synthesis of Aminomethylphenol Derivatives in Cyclopentyl Methyl Ether via Petasis Borono-Mannich Reaction

2020 ◽  
Vol 17 ◽  
Author(s):  
Jia-Qi Di ◽  
Hao-Jie Wang ◽  
Zhen-Shui Cui ◽  
Jin-Yong Hu ◽  
Zhan-Hui Zhang
Keyword(s):  
Secondary Amine ◽  
Methyl Ether ◽  
Mannich Reaction ◽  
Phenylboronic Acid ◽  
Functional Materials ◽  
Practical Method ◽  
Model Reaction ◽  
Arylboronic Acid ◽  
Reaction Conditions ◽  
Catalyst Free

Objective: Aminomethylphenol molecules have wider applications in pharmaceuticals, agrochemicals, plant protection and promising functional materials. The development of an efficient and practical method to prepare this class of compound is highly desirable from both environmental and economical points of views. Materials and Methods: In order to establish an effective synthetic method for preparing aminomethylphenol derivatives, the Petasis borono-Mannich reaction of salicylaldehyde, phenylboronic acid and 1,2,3,4-tetrahydroisoquinoline was selected as a model reaction. A variety of reaction conditions are investigated including solvent and temperature. The generality and limitation of the established method were also evaluated. Results and Discussion: It was found that model reaction can be carried out in cyclopentyl methyl ether at 80 oC under catalyst-free condition. This protocol with a broad substrate applicability, the reaction of various arylboronic acid, secondary amine and salicylaldehyde proceeded smoothly under optimal reaction conditions to afforded various aminomethylphenol derivatives in high yields. A practical, scalable, and high-yielding synthesis of aminomethylphenol derivatives was successfully accomplished. Conclusion: A catalyst-free practical method for the synthesis of minomethylphenol derivatives based on Petasis borono– Mannich (PBM) reaction of various arylboronic acid, secondary amine and salicylaldehyde in cyclopentyl methyl ether has been developed. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvents, use cyclopentyl methyl ether as the reaction medium, clean reaction profiles, easy operation, and high to excellent yield.

A New Catalyst on Di(1-Naphthyl)methane Hydrocracking and Kinetics Analysis

2011 ◽  
Vol 236-238 ◽  
pp. 771-774
Author(s):  
Xiao Ming Yue ◽  
Zhi Min Zong ◽  
Bing Sun ◽  
Ying Hua Wang ◽  
Yu Qing ◽  
...  
Keyword(s):  
Activation Energy ◽  
Reaction Times ◽  
Order Reaction ◽  
Model Reaction ◽  
Coal Liquefaction ◽  
Kinetics Analysis ◽  
Reaction Conditions ◽  
Exponential Factor ◽  
Active Constituents ◽  
First Order

A new catalyst with two active constituents interacting with activated carbon was prepared. As a model reaction for coal liquefaction, the hydrocracking of di(1-naphthyl)methane (DNM) was investigated under different reaction conditions over the catalyst. The results show that the catalyst converts DNM hydrocraking into 1-methylnaphthalene and naphthalene with high selectively, without any hydrogenation product. Kinetic analysis indicates that DNM hydrocracking in the temperature range of 170-300 °C could be considered as a first order reaction. The activation energy E and pre-exponential factor A for DNM hydrocracking for different reaction times were calculated.

scholarly journals Effects of Microwave Irradiation on Activation Energy and Reaction Rate of Synthesis of Dodecylmethyldihydroxyl Ammonium Bromide

2011 ◽  
Vol 396-398 ◽  
pp. 1044-1047 ◽  
Author(s):  
Tao Yan Mao ◽  
Cheng Zheng ◽  
Jimmy Yu
Keyword(s):  
Activation Energy ◽  
Microwave Irradiation ◽  
Reaction Rate ◽  
Conventional Heating ◽  
Irradiation Condition ◽  
Ammonium Bromide ◽  
Reaction Conditions ◽  
First Order ◽  
Conventional Condition ◽  
Kinetics Of

The reaction kinetics of the synthesis of quaternary ammonium salt under two sets of different reaction conditions, including microwave irradiation condition and conventional heating condition, were studied. In order to make sure that the microwave would not be interrupted, the reaction temperature was maintained at the boiling point of reaction solvents. The results showed that the reaction was a first-order reaction under both set of conditions and microwave irradiation changed the value of the activation energy of the reaction, indicating a change in the reaction mechanism. The activation energy was 41.44 kJ/mol under microwave irradiation condition, and 61.21 kJ/mol under conventional condition.

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