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排序方式: 共有169条查询结果,搜索用时 250 毫秒
91.
Vahideh Zadsirjan Majid M. Heravi Mahmoud Tajbakhsh Hossein A. Oskooie Morteza Shiri Tayebeh Hosseinnejad 《Research on Chemical Intermediates》2016,42(7):6407-6422
Hydroarylation of cinnamic acid with different substituted phenols, in the presence of acidic ionic liquid, N-methyl-2-pyrrolidonum hydrosulfate ([H-NMP]HSO4) gave the corresponding dihydrocoumarins in high yields and excellent selectivity. Among these substituted phenols, while methyl phenol afforded the corresponding dihydrocoumarin, nitrophenol under the same reaction conditions diverted the course of reaction, affording 3-(4-nitrophenyl)-3-phenylpropanoic acids. We investigated this behavior from the energetic and electronic points of view, using quantum chemistry computational methods. In this respect, the electronic energy change values for the conversion reaction of substituted phenyl cinnamate esters to dihydrocoumarin compounds have been obtained via density functional theory calculations. We demonstrated that the conversion reaction in the presence of CH3 substituent is more favorable energetically than NO2 substituent. Moreover, we have concentrated on topological analysis of electron density on some key bond and ring critical points and their associated bond paths to assess the conversion of substituted phenyl cinnamate esters to dihydrocoumarins. Our calculated results showed that para-methyl phenyl cinnamate has more of electronic tendency to undergo the intramolecular cyclization step and, consequently, generate the corresponding dihydrocoumarin. 相似文献
92.
Mahmood Tajbakhsh Moosa Ghaemi Siavosh Sarabi Mitra Ghassemzadeh Majid M. Heravi 《Monatshefte für Chemie / Chemical Monthly》2000,131(11):1213-1216
Summary. N-Methyl piperidinium chlorochromate adsorbed on alumina oxidizes a wide variety of benzylic alcohols to the corresponding
carbonyl compounds.
Received May 18, 2000. Accepted (revised) July 4, 2000 相似文献
93.
Babaei Fatemeh Asghari Sakineh Tajbakhsh Mahmoud 《Research on Chemical Intermediates》2019,45(9):4693-4709
Research on Chemical Intermediates - New amine modified nanozeolites were prepared and characterized using FT-IR, TGA, DTG, SEM, and TEM. Then the synthesized nanozeolites were employed as novel,... 相似文献
94.
Saeid Tajbakhsh Milan Marić 《Journal of polymer science. Part A, Polymer chemistry》2021,59(6):547-560
SG1-based amphiphilic macroinitiators were synthesized from oligoethylene glycol methyl ether methacrylate and 10 mol% acrylonitrile or styrene (as the controlling comonomer) to conduct the nitroxide mediated polymerization of bio-based methacrylic monomers (isobornyl methacrylate (IBOMA) and C13 alkyl methacrylate (C13MA)) in miniemulsion. The effect of the addition of surfactant (DOWFAX 8390), co-stabilizer (n-hexadecane) and different reaction temperatures (80, 90 and 100°C) on polymerization kinetics was studied. We found that the NMP of IBOMA/C13MA using amphiphilic macroalkoxyamines were most effective during miniemulsion polymerization (linear trend of Mn versus conversion and high latex stability) in presence of 2 wt% surfactant and 0.8 wt% co-stabilizer (relative to monomer) at 90°C. The effect of surfactant, co-stabilizer and temperature on particle size during the polymerization was studied and suggested a decrease in initial particle size with the addition of surfactant and co-stabilizer. Finally, the thermal properties of IBOMA/C13MA polymers, prepared by amphiphilic macroinitiators, were examined thoroughly, indicating a Tg in the range of −44°C < Tg < 109°C. 相似文献
95.
Noguchi T Tanaka N Nishimata T Goto R Hayakawa M Sugidachi A Ogawa T Asai F Matsui Y Fujimoto K 《Chemical & pharmaceutical bulletin》2006,54(2):163-174
A series of bisamidine derivatives each having a ring structure in the center of the molecule was synthesized and their Factor Xa (FXa) inhibitory activities were evaluated. Among them, some indoline derivatives showed potent inhibitory activities in vitro. In particular, (R)-18a having an (R)-configuration at the 2-position of the indoline ring exhibited the most potent FXa inhibitory activity in vitro, more potent than DX-9065a. Furthermore, (R)-18a exhibited more potent anticoagulant activity than DX-9065a. We also succeeded in obtaining an X-ray crystal structure of FXa bound with (R)-18a. 相似文献
96.
97.
98.
A regioselective and convenient procedure for preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of sulfuric acid supported on silica gel as an active, inexpensive, and recoverable catalyst under heterogeneous and solvent-free conditions at room temperature is described. 相似文献
99.
A tetrameric DABCO–bromine complex was synthesized, characterized, and utilized as a novel active bromine complex for the oxidative deprotection of THP and silyl ethers and semicarbazones to carbonyl compounds. 相似文献
100.
Mahmood Tajbakhsh Rahman Hosseinzadeh Heshmatollah Alinezhad Parizad Rezaee 《合成通讯》2013,43(17):2370-2379
Silica-bonded S-sulfonic acid nanoparticles (SBSSANPs) were easily synthesized from silica nanoparticles and showed to be an efficient catalyst in the synthesis the symmetrical N,N′-alkylidene bisamides. Reaction of aldehydes and amides in the presence of the catalyst afforded the corresponding bisamides in good to excellent yields. The extensive range of substrates suggests general applicability of the method. Reusability of the catalyst, simple workup procedure, and short reaction times are other advantages of this protocol. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications ® to view the free supplemental file. 相似文献