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71.
Iraj Mohammadpoor-Baltork Ahmad R. Khosropour Majid Moghadam Shahram Tangestaninejad Valiollah Mirkhani Saeid Baghersad Arsalan Mirjafari 《Comptes Rendus Chimie》2011,14(10):944-952
An efficient and novel synthesis of 2,3-disubstituted 2,3-dihydroquinazolin-4(1H)-ones via one-pot, three-component reaction of isatoic anhydride, primary amines and aromatic aldehydes catalyzed by Bi(NO3)3·5H2O under solvent-free conditions is described. Oxidation of these 2,3-dihydroquinazolin-4(1H)-ones to their quinazolin-4(3H)-ones was also successfully performed in the presence of Bi(NO3)3·5H2O. This new method has the advantages of convenient manipulation, short reaction times, excellent yields, very easy work-up, and the use of commercially available, low cost and relatively non-toxic catalyst. The role of Bi(NO3)3·5H2O was also investigated in these transformations. 相似文献
72.
Mahboubeh Rostami Ahmad Reza Khosropour Valiollah Mirkhani Iraj Mohammadpoor-Baltork Majid Moghadam Shahram Tangestaninejad 《Monatshefte für Chemie / Chemical Monthly》2011,7(1):1175-1180
Abstract
A new and practical promoter system for one-pot, efficient, chemoselective synthesis of 4-arylidene-2-phenyl-5(4H)-oxazolones using [(C14H24N4)2W10O32]-[bmim]NO3 under solvent-free conditions is described. The present work opens up a new and ecofriendly synthetic route to Erlenmeyer–Pl?chl adducts from primary benzyl alcohols in a one-pot operation. 相似文献73.
Maryam YadegariMajid Moghadam Shahram TangestaninejadValiollah Mirkhani Iraj Mohammadpoor-Baltork 《Polyhedron》2011,30(13):2237-2243
In the present work, a highly efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by high-valent [TiIV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were acetylated with short reaction times and high yields. The catalyst was reused several times without loss of its catalytic activity. 相似文献
74.
In this paper we study the behavior of computable series of computable partial functions with varying domains (but each domain containing all computable points), and prove that the sum of the series exists and is computable exactly on the intersection of the domains when a certain computable Cauchyness criterion is met. In our point‐free approach, we name points via nested sequences of basic open sets, and thus our functions from a topological space into the reals are generated by functions from basic open sets to basic open sets. The construction of a function that produces the sum of a series requires working with an infinite array of pairs of basic open sets, and reconciling the varying domains. We introduce a general technique for using such an array to produce a set function that generates a well‐defined point function and apply the technique to a series to establish our main result. Finally, we use the main finding to construct a computable, and thus continuous, function whose domain is of Lebesgue measure zero and which is nonextendible to a continuous function whose domain properly includes the original domain. (We had established existence of such functions with domains of measure less than ε for any , in an earlier paper.) 相似文献
75.
Majid Soolaki Iraj Mahdavi Nezam Mahdavi-Amiri Reza Hassanzadeh Aydin Aghajani 《Applied Mathematical Modelling》2012
The airline industry is under intense competition to simultaneously increase efficiency and satisfaction for passengers and profitability and internal system benefit for itself. The boarding process is one way to achieve these objectives as it tends itself to adaptive changes. In order to increase the flying time of a plane, commercial airlines try to minimize the boarding time, which is one of the most lengthy parts of a plane’s turn time. To reduce boarding time, it is thus necessary to minimize the number of interferences between passengers by controlling the order in which they get onto the plane through a boarding policy. Here, we determine the passenger boarding problem and examine the different kinds of passenger boarding strategies and boarding interferences in a single aisle aircraft. We offer a new integer linear programming approach to reduce the passenger boarding time. A genetic algorithm is used to solve this problem. Numerical results show effectiveness of the proposed algorithm. 相似文献
76.
Hossein Salavati Shahram Tangestaninejad Majid Moghadam Valiollah Mirkhani Iraj Mohammadpoor-Baltork 《Ultrasonics sonochemistry》2010,17(1):145-152
A Keggin-type heteropolyanion compound (HPO) was doped within the montmorillonite (MMT) structure by impregnation method. The synthesized catalyst was characterized by FT-IR, XRD, UV–vis, CV, SEM and elemental analysis. Based on chemical adsorption between HPO, and hydroxyl surface groups, HPOs nanoparticles were successfully located on the MMT. Moreover, the obtained nanocomposite was found as an efficient catalyst for oxidation of hydrocarbons under reflux and ultrasonic irradiation conditions. 相似文献
77.
Tangestaninejad S Mirkhani V Moghadam M Mohammadpoor-Baltork I Shams E Salavati H 《Ultrasonics sonochemistry》2008,15(4):438-447
Vanadium polyoxometalate (PVMo) supported on mesoporous MCM-41, MCM-41-NH(2), as efficient and heterogeneous catalysts, with large surface area, for hydrocarbon oxidation with hydrogen peroxide is reported. Oxidation of the alkenes and alkanes gave product selectivities, which are similar to those observed for corresponding homogeneous catalyst. PVMo-MCM was prepared by introduction of PVMo into the mesoporous molecule sieves of MCM-41 by impregnation and adsorption techniques. The samples were characterized by X-ray diffraction (XRD), thermal gravimetric-differential thermal analysis (TG-DTA), FT-IR, scanning electron microscopy (SEM), UV-Vis and cyclic voltametry (CV). Ultrasonic irradiation has a particular effect on MCM-41 structural uniformity and reduced the reaction times and improved the product yields. In addition, the solid catalysts could be recovered and reused several times without loss of its activity. 相似文献
78.
Thiocyanation of various aromatic and heteroaromatic compounds has been achieved in the presence of ammonium thiocyanate (NH(4)SCN) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in methanol solution under ultrasound irradiation. An ultrasonic probe of 24 kHz frequency has been used for this study. Whereas the use of ultrasound increases the rate of reactions compared with reactions at reflux conditions, the electron-donor ability of aromatic nucleus enhances also the rate of reaction. 相似文献
79.
Débora de Oliveira Irajá do Nascimento Filho Marco di Luccio Carina Faccio Clarissa Dalla Rosa João Paulo Bender Nádia Lipke Cristiana Amroginski Cláudio Dariva José Vladimir de Oliveira 《Applied biochemistry and biotechnology》2005,121(1-3):231-241
This work investigated the production of fatty acid ethyl esters (FAEEs) from soybean oil using n-hexane as solvent and two commercial lipases as catalysts, Novozym 435 and Lipozyme IM. A Taguchi experimental design was
adopted considering the variables temperature (35–65°C), addition of water (0–10 wt/wt%), enzyme (5–20 wt/wt%) concentration,
and oil-to-ethanol molar ratio (1:3–1:10). It is shown that complete conversion in FAEE is achieved for some experimental
conditions. The effects of process variables on reaction conversion and kinetics of the enzymatic reactions are presented
for all experimental conditions investigated in the factorial design. 相似文献
80.
In this paper we introduce a new method to the cluster analysis of longitudinal data focusing on the determination of uncertainty levels for cluster memberships. The method uses the Dirichlet-t distribution which notably utilizes the robustness feature of the student-t distribution in the framework of a Bayesian semi-parametric approach together with robust clustering of subjects evaluates the uncertainty level of subjects memberships to their clusters. We let the number of clusters and the uncertainty levels be unknown while fitting Dirichlet process mixture models. Two simulation studies are conducted to demonstrate the proposed methodology. The method is applied to cluster a real data set taken from gene expression studies. 相似文献