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121.
Michail N. Elinson Alexey I. Ilovaisky Valentina M. Merkulova Pavel A. Belyakov Alexander O. Chizhov Gennady I. Nikishin 《Tetrahedron》2010,66(23):4043-6439
The new type of solvent-free cascade reaction was found: the direct heating of the mixture of salicylaldehyde, malononitrile or cyanoacetate and nitroalkanes at 60 °C in the presence of catalytic amounts of KF or NaOAc results in the formation of 2-amino-4-(1-nitroalkyl)-4H-chromene-3-carbonitriles or methyl 2-amino-4-(1-nitroalkyl)-4H-chromene-3-carboxylates in 80-90% yields. Thus, the new simple and efficient solvent-free ‘one-pot’ way to substituted medicinally privileged 2-amino-4H-chromene scaffold was found directly from such simple and reasonable starting compounds as salicylaldehyde, malononitrile or cyanoacetate and nitroalkanes. 相似文献
122.
Yu Zou Michail E. Kavousanakis Ioannis G. Kevrekidis Rodney O. Fox 《Journal of computational physics》2010,229(14):5299-5314
The study of particle coagulation and sintering processes is important in a variety of research studies ranging from cell fusion and dust motion to aerosol formation applications. These processes are traditionally simulated using either Monte-Carlo methods or integro-differential equations for particle number density functions. In this paper, we present a computational technique for cases where we believe that accurate closed evolution equations for a finite number of moments of the density function exist in principle, but are not explicitly available. The so-called equation-free computational framework is then employed to numerically obtain the solution of these unavailable closed moment equations by exploiting (through intelligent design of computational experiments) the corresponding fine-scale (here, Monte-Carlo) simulation. We illustrate the use of this method by accelerating the computation of evolving moments of uni- and bivariate particle coagulation and sintering through short simulation bursts of a constant-number Monte-Carlo scheme. 相似文献
123.
Catalysis of Cascade and Multicomponent Reactions of Carbonyl Compounds and CH Acids by Electricity
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Michail N. Elinson Anatoly N. Vereshchagin Fedor V. Ryzhkov 《Chemical record (New York, N.Y.)》2016,16(4):1950-1964
This review is concerned with modern trends in the use of electrochemically induced chain reactions in cascade and multicomponent electroorganic synthesis. The review summarizes the data on the use of electrochemically induced chain reactions in cascade and multicomponent organic synthesis, which were published mainly in the last decade. 相似文献
124.
125.
Alexander L. Nivorozhkin Hans Toftlund Leonid E. Nivorozhkin Irina A. Kamenetskaya Alla S. Antsishkina Michail A. Porai-Koshits 《Transition Metal Chemistry》1994,19(3):319-324
Summary Tetracoordinate nickel(II) complexes NiL2 derived from the deprotonated forms of aminoazoligands HL were prepared and investigated by spectroscopy and magnetic susceptibility measurements. The magnetic moments, which lie in the 3.1–3.6 B.M. range correspond to the occurrence both in solution and in the solid state of the high spin (S = 1) form and a tetrahedral configuration at the metal centre. The u.v. spectra exhibit three ligand field bands at 1020–1280 nm characteristic of high spin nickel(II) complexes. The large isotropic chemical shifts found in the 1H n.m.r. spectra are consistent with partial delocalization of unpaired electron spin density to the ligand HOMO. The X-ray single crystal structure of NiL
2
4
[L4= 1-isopropyl-3-methyl-4-(4-methylphenylazo)-5-(4-methoxyphenylamino)-pyrazole] reveals that the metal is coordinated by four nitrogen atoms in tetrahedral configuration with an angle of 90° between the N(1)NiN(2) and N(6)NiN(7) planes belonging to the different almost planar metallocycles. The rates of RS interconversion of the tetrahedral configuration for NiL
2
4
and NiL
2
5
[L5 = 1-isopropyl-3-methyl-4-phenylazo-d
5-5-(4-methoxyphenylamino)pyrazole] are slow on the n.m.r. timescale. In contrast to NiL
2
1
-Ni
2
6
, NiL
2
7
], which contains coordinated NH-groups instead of NAr-groups, is planar. 相似文献
126.
Quantum Neural Nets 总被引:1,自引:0,他引:1
The capacity of classical neurocomputers islimited by the number of classical degrees of freedom,which is roughly proportional to the size of thecomputer. By contrast, a hypothetical quantumneurocomputer can implement an exponentially larger number ofthe degrees of freedom within the same size. In thispaper an attempt is made to reconcile the linearreversible structure of quantum evolution with nonlinear irreversible dynamics for neuralnets. 相似文献
127.
Almir S. Gazizov Andrey V. Smolobochkin Julia K. Voronina Alexander R. Burilov Michail A. Pudovik 《合成通讯》2013,43(10):1215-1221
1-(4,4-Diethoxybutyl)-3-alkylureas undergo intramolecular cyclization in the presence of trifluoroacetic acid and various phenols, leading to the new N-alkyl-2-arylpyrrolidine-1-carboxamides with moderate to excellent yields. It was found that these compounds undergo spontaneous solid-phase epimerization at room temperature. Advantages of the proposed approach are mild reaction conditions and no need for expensive reagents or catalysts. 相似文献
128.
Ryzhkov Fedor V. Elinson Michail N. Ryzhkova Yuliya E. Vereshchagin Anatoly N. Fakhrutdinov Artem N. Egorov Mikhail P. 《Chemistry of Heterocyclic Compounds》2021,57(6):672-678
Chemistry of Heterocyclic Compounds - Electrocatalytic cascade assembly of benzylidenebarbiturates and cyclohexane-1,3-diones in methanol in the presence of sodium bromide as mediator in an... 相似文献
129.
Fast Efficient and General PASE Approach to Medicinally Relevant 4H,5H‐Pyrano‐[4,3‐b]pyran‐5‐one and 4,6‐Dihydro‐5H‐pyrano‐[3,2‐c]pyridine‐5‐one Scaffolds
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Michail N. Elinson Fedor V. Ryzhkov Ruslan F. Nasybullin Anatoly N. Vereshchagin Mikhail P. Egorov 《Helvetica chimica acta》2016,99(9):724-731
The general ‘on‐solvent’ PASE approach was found to be medicinally relevant for 4H,5H‐pyrano[4,3‐b]pyran‐5‐one and 4,6‐dihydro‐5H‐pyrano[3,2‐c]pyridine‐5‐one scaffolds. Ammonium acetate‐catalyzed multicomponent reaction of aldehydes and two different C–H acids in the presence of small amounts of EtOH results in fast (3 – 15 min) and efficient formation of scaffolds, promising for many diverse oriented medical applications. 相似文献
130.
The molecular dynamics (MD) simulation technique has been employed to investigate the thermodynamic properties and transport coefficients of the neat liquid dimethyl sulfoxide (DMSO). The fluid has been studied at temperatures in the range 298–353 K and at a pressure equal to 1 atm. The simulations employed a nine-site potential model, which is presented for the first time here, and all the available non-polarizable models. The performance of each model is tested using the same statistical mechanical ensemble and simulation method under the same conditions, revealing its weaknesses and strengths. Thermodynamic properties, microscopic structure and dynamic properties, such as transport coefficients, rotational and single-dipole correlation times have been calculated and compared with available experimental results. Estimations of transport coefficients from various theoretical and empirical models are tested against experimental and MD results. Translational and rotational dynamics suggest the existence of the cage effect and agree with the Stokes–Einstein–Debye relation. The dipole relaxation times calculated are discussed in terms of simple and useful approximations, such as the Glarum–Powles and Fatuzzo–Mason models. 相似文献