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1.
An efficient and novel copper-mediated protocol for the synthesis of 3-amino-1,4-enynes from glyoxylic acid, an amine, and an alkyne was developed. This new reaction involving two sequential C-C bond formations is air and moisture tolerant and proceeds via a tandem A(3)-coupling and a selective decarboxylative coupling. 相似文献
2.
Gajare Shivanand Patil Audumbar Hangirgekar Shankar Dhanmane Sushilkumar Rashinkar Gajanan 《Research on Chemical Intermediates》2020,46(5):2417-2436
Research on Chemical Intermediates - Graphene oxide-supported Bronsted acidic ionic liquid ([GrBenzImi]SO3H) has been prepared by covalent grafting of benzimidazole unit in the matrix of graphene... 相似文献
3.
《中国化学快报》2020,31(6):1558-1563
Highly active and stable magnetic copper catalysts were successfully achieved by magnetic induced Stober method and subsequent hydrothermal reaction with copper ions in alkaline condition.The high content of Cu~(2+) as well as the unique structures of hierarchical copper silicate in the as-prepared catalysts endowed their outstanding catalytic performance.Efficient decarboxylative A~3-coupling of a-keto acid,amine and alkyne was realized with the low Fe_3 O_4@CuSiO_3 loading.A range of propargylamines were produced in good to excellent yields under solvent-free condition.Moreover,the catalyst can be easily separated from the final organic product with an external magnet.Also,this kind of catalyst could be recycled up to six times while maintaining its activity. 相似文献
4.
《中国化学快报》2021,32(12):3993-3997
Several simple, fast and practical protocols have been developed to synthesize internal or terminal propargylamines and chalcones via A3-coupling reaction of aldehydes, amines, and alkynes catalyzed by an easily available catalyst Ag2CO3 under solvent-free condition. The reaction proceeded smoothly to deliver various products in good-to-excellent yields with good functional group tolerance. Gram-scale preparation, bioactive molecule synthesis and asymmetric substrates have been demonstrated. Furthermore, plausible mechanisms for the synthesis of different products have been proposed. 相似文献
5.
We have explained in detail why the canonical partition function of interacting self-avoiding walk (ISAW) is exactly equivalent to the configurational average of the weights associated with growth walks, such as the interacting growth walk (IGW), if the average is taken over the entire genealogical tree of the walk. In this context, we have shown that it is not always possible to factor the density of states out of the canonical partition function if the local growth rule is temperature dependent. We have presented Monte Carlo results for IGWs on a diamond lattice in order to demonstrate that the actual set of IGW configurations available for study is temperature dependent even though the weighted averages lead to the expected thermodynamic behavior of ISAW. 相似文献
6.
《Tetrahedron: Asymmetry》2014,25(5):429-434
A novel thiosalen ligand based on a thioether has been prepared and readily coordinated with copper(I) salts (CuCl, CuBr, CuI, and CuCN). The new organometallic catalyst was used for the direct and enantioselective alkynylations of imines in an A3-coupling reaction. In this reaction, the corresponding propargylamines were obtained as single products in excellent yields and with good enantioselectivities. 相似文献
7.
José Ricardo Cammarata Rocío Rivera Franmerly Fuentes Yomaira Otero Edgar Ocando-Mavárez Alejandro Arce Juan M. Garcia 《Tetrahedron letters》2017,58(43):4078-4081
An air stable copper(I)-phosphole complex, [CuCl{2,5-bis(2-thienyl)-1-phenylphosphole}2] (1), was utilized as a catalyst in single and double A3-coupling reactions for preparing mono- and bi-propargylamines. A variety of aldehydes, amines and terminal alkynes were tested. Most of these reactions led to formation of the expected propargylamines in good yields using low amounts catalyst and obviating both the use of purified reagents as employ of a glovebox. 相似文献
8.
《Journal of Coordination Chemistry》2012,65(11):1810-1819
AbstractA new 2D copper(I) coordination polymeric complex has been synthesized from CuI and 1-(1-{4-chlorophenylthio}propan-2-ylthio)-4-chlorobenzene ([(CuI)2{ArSCH2CH(CH3)SAr}2]n, Ar = 4-ClC6H4) and characterized by high resolution mass spectrometry (HRMS) and single crystal X-ray diffraction techniques. The complex has been employed as a suitable catalyst for a solvent-free, one-pot, three-component A3-coupling reaction. A variety of aromatic and aliphatic aldehydes, terminal alkynes and aliphatic cyclic secondary amines have been used to prepare a library of propargylamines using the 2D-Cu complex at significantly low concentration (0.2?mol%). 相似文献
9.
10.
An exact mathematical treatment of the random walk model in chromatography is given in this paper. Various factors which can cause broadening of peaks, such as equilibium fluctuation, diffusion, size and structure of fixed phase particles, fluid velocity, flow around the particles, distribution ratio, column temperature and nonuniformity, etc., are all considered with a unified theory. Formulas of mean retention time and height of theoretical plate, containing all of the factors, are presented. 相似文献
11.
A method of calculating rates of homogeneous vapor-liquid nucleation based on Langevin dynamics of a few relevant degrees of freedom on a free-energy surface is proposed. The surface is obtained here from simulation and from a semi empirical expression. The mass and friction coefficients are derived from atomistic umbrella-sampling molecular-dynamics simulations. The calculated nucleation rate agrees with atomistic simulations for one particular state point of the Lennard-Jones fluid. The present method is about four orders of magnitude more computationally efficient than the direct atomistic simulation of the transmission coefficient. 相似文献
12.
Naghmeh Esfandiary Farzane Pazoki Athar Nakisa Kobra Azizi Iman Radfar Akbar Heydari 《应用有机金属化学》2020,34(8):e5725
A highly efficient Fe3O4@VitB1–Ag(I) magnetic catalyst has been obtained using surface modification of Fe3O4. To this end, silver chloride was immobilized on Fe3O4 nanoparticles via vitamin B1 biomolecules. The synthesized biocompatible magnetic catalyst was applied in an A3-coupling reaction in the presence of aldehyde, amine and phenyl acetylene under solvent-free conditions and afforded the desired products in excellent yields. Also, interactions between metal and ligand in the Fe3O4@VitB1–Ag(I) were studied using theoretical calculations. 相似文献
13.
Dispersion and chemical reaction in a single-channel flow-injection system are modelled by a random walk (stochastic, Markovian chain) method using a microcomputer. The effects of various simulated physical variables are investigated. The model provides valuable insight into the mixing process in flow injection analysis. 相似文献
14.
Jean Leopold Ndeugueu Masahiro Ikeda Masaru Aniya 《Journal of Thermal Analysis and Calorimetry》2010,99(1):33-38
We have studied the temperature dependence of the viscosity of some polymeric materials by using both, the bond-strength-coordination
number fluctuation model and the random walk model. The results reveal that both models show an excellent agreement with the
experimental data. For the random walk model, two equations corresponding to two temperature regimes (low-T and high-T) separated by the critical temperature T
c, which is difficult to determine, are needed to describe the temperature dependence of the viscosity of a fragile system,
whereas for the bond-strength-coordination number fluctuation model, a single equation with clear physical meaning describes
the temperature dependence of the viscosity of both, the fragile and strong systems. We have also studied the relationship
between the normalized temperature range of cooperativity and the fragility index. A theoretical expression for the relationship
has been derived based on the bond-strength-coordination number fluctuation model. The comparison with the experimental data
shows a good agreement, leading to the conclusion that the kinetic properties of glass forming liquids and the cooperativity
of molecular relaxations are correlated. 相似文献
15.
A. S. Padmanabhan 《Journal of mathematical chemistry》2014,52(1):355-367
The Growing self avoiding walk model (GSAW) was proposed to explain statistical mechanics of the growth process in polymerization. Close examination of the model reveals that it is suited only for addition polymerization where only one monomer unit is added to the growing polymer chain. In this paper we propose a model for step growth or condensation polymerisation, where all of the monomer is converted first to dimer, all dimers are converted to tetramer etc. In the calculation of probabilities of the walker taking a step in a specified direction in the GSAW model the probability is the reciprocal of the number of steps available if the walker looks one step ahead. It is seen that our model for condensation polymerization GSAW can be generalized to the walker looking a finite number of steps ahead (instead of one only) for the purpose of calculation of probabilities. This is explained in detail in the first section of the paper. In the second section of the paper we explain the use of the Depth first search (DFS) algorithm in the calculation of probabilities and moments for the generalized growing self avoiding walk model. In the third section of the paper we report the exact values of the mean square end to end distances and relevant survival probabilities for the model. When GSAW was first proposed there was a controversy over whether it belonged to the same universality class as the True self avoiding walk $\left( \upsilon =\frac{2}{d+1}\right) $ or that of the self avoiding walk $\left( \upsilon =\frac{3}{d+2}\right) $ . At that time it was conclusively shown that the GSAW model cannot belong to the same universality class as the true self avoiding walk model. However it was never conclusively shown that $\upsilon =\frac{3}{d+2}$ for GSAW. In this paper we propose two methods of studying this problem. One method is rigorous analysis of the DFS algorithm. We explain how this algorithm can be used to study restricted random walks with finite memory and self avoiding walks. The second method proposed by us is a detailed analysis of the generalised GSAW model proposed by us. This paper is to be viewed as an introductory paper on a new model that should be of interest to both chemists and mathematicians. 相似文献
16.
A capillary electrophoresis (CE) system has been developed to provide routine purity information to support synthetic organic chemists. A single micellar electrokinetic chromatography system that produces good selectivity with short run times was developed. The instrument operating software has been modified to run separations in a custom open access mode. No expert knowledge of CE is required to run separations. 相似文献
17.
Marie Barbarotto Julie Geist Sabine Choppin Françoise Colobert 《Tetrahedron: Asymmetry》2009,20(24):2780-2787
Chiral non-racemic α-bromo-α′-sulfinyl ketones were shown to react with imines in the presence of SmI2 to give the corresponding 1,3-aminoketo derivatives with good syn-diastereoselectivity. Further reduction of these adducts either with DIBAL-H only or with DIBAL-H in the presence of Yb(OTf)3 afforded syn- and anti-2-methyl-3-amino-1-ol moieties, respectively, in good yields and diastereoselectivities. 相似文献
18.
Feng H Ermolat'ev DS Song G Van der Eycken EV 《The Journal of organic chemistry》2012,77(11):5149-5154
A novel microwave-assisted approach for the one-pot Cu(I)-catalyzed A(3)-coupling/decarboxylative coupling (PA(2)-coupling) of a propiolic acid, an aldehyde, and an amine, resulting in the formation of diversely substituted 1,4-diamino-2-butynes,is described. It is noteworthy that this new multicomponent coupling provides an efficient access to introduce alkyl and aryl group at the 1,4-position of the 1,4-diamino-2-butynes. 相似文献
19.
Atomic walk counts (awc's) of order k (k > or = 1) are the number of all possible walks of length k which start at a specified vertex (atom) i and end at any vertex j separated by m (0 < or = m < or = k) edges from vertex i. The sum of atomic walk counts of order k is the molecular walk count (mwc) of order k. The concept of atomic and molecular walk counts was extended to zero and negative orders by using a backward algorithm based on the usual procedure used to obtain the values of mwc's. The procedure can also be used in cases in which the adjacency matrix A related to the actual structure is singular and therefore A(-1) does not exist. awc's and mwc's of negative order may assume noninteger and even negative values. If matrix A is singular, atomic walk counts of zero order may not be equal to one. 相似文献