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1.
手性奎宁-卟啉锰催化剂的合成及其催化性能 总被引:1,自引:0,他引:1
为了寻找催化活性、相转移活性和手性诱导为一体的卟啉配体[1-4],我们把卟啉和手性相转移源连结起来,用奎宁-卟啉化合物作配体[5],考察其锰 配合物为催化剂对烯烃环氧化反应的催化性能。奎宁-卟啉锰 配合物结构式如下:1 实验部分1.1 试剂和仪器苯乙烯和α-甲基苯乙烯在氮气保护下减压蒸馏处理。氧源NaOCl的浓度由碘量法测定。其余试剂均为化学纯,色谱标样环氧苯乙烯和α-甲基环氧苯乙烯按文献[6]方法合成。奎宁-卟啉配体按文献[5]合成。260-50型红外光谱仪,KBr压片;UV-3000型紫外可见光谱仪,溶剂DMF;MT-3型CHN元素… 相似文献
2.
This paper describes a highly enantioselective epoxidation of alpha,beta-unsaturated esters using the fructose-derived ketone 2 as catalyst and Oxone as oxidant. High ee's have been obtained for a number of trans and trisubstituted substrates (82-98% ee). The results described show that it is feasible for dioxiranes to effectively epoxidize electron-deficient olefins with high ee's. 相似文献
3.
PS-TEMPO, a polymer-supported 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), was successfully applied as a recyclable, active and selective catalyst for the oxidation of primary aliphatic and benzylic alcohols to aldehydes by molecular oxygen in the presence of Co(NO3)2 and Mn(NO3)2 as co-catalysts. 相似文献
4.
5.
Fluorinated phenethyl bromides 1,2 , and 3 , prove to be totally inert under Ritter reaction conditions in the presence of either SnCl4 or AgNO3, due to the strong deactivation by the gem‐difluoro unit. Subjecting 2‐bromo‐1‐fluoro‐1‐phenylethane to SnCl4 in MeCN at elevated temperatures led to formation of 2‐methyl‐4‐phenyl‐4,5‐dihydrooxazole. 相似文献
6.
An enantioselective synthesis of (+)‐β‐himachalene ( 2 ) was accomplished starting from (1S,2R)‐1,2‐epoxy‐p‐menth‐8‐ene ( 3 ) in 15 or 16 steps with an overall yield of ca. 6% (Schemes 3, 5, and 6). Key transformations include an Ireland–Claisen rearrangement, a Corey oxidative cyclization, and a ring expansion. 相似文献
7.
Lok P. Singh Sriman K. BhattacharyyaRahul Kumar Geetika MishraUsha Sharma Garima SinghSaurabh Ahalawat 《Advances in colloid and interface science》2014
Recently, silica nanoparticles (SNPs) have drawn widespread attention due to their applications in many emerging areas because of their tailorable morphology. During the last decade, remarkable efforts have been made on the investigations for novel processing methodologies to prepare SNPs, resulting in better control of the size, shape, porosity and significant improvements in the physio-chemical properties. A number of techniques available for preparing SNPs namely, flame spray pyrolysis, chemical vapour deposition, micro-emulsion, ball milling, sol-gel etc. have resulted, a number of publications. Among these, preparation by sol-gel has been the focus of research as the synthesis is straightforward, scalable and controllable. Therefore, this review focuses on the recent progress in the field of synthesis of SNPs exhibiting ordered mesoporous structure, their distribution pattern, morphological attributes and applications. The mesoporous silica nanoparticles (MSNPs) with good dispersion, varying morphology, narrow size distribution and homogeneous porous structure have been successfully prepared using organic and inorganic templates. The soft template assisted synthesis using surfactants for obtaining desirable shapes, pores, morphology and mechanisms proposed has been reviewed. Apart from single template, double and mixed surfactants, electrolytes, polymers etc. as templates have also been intensively discussed. The influence of reaction conditions such as temperature, pH, concentration of reagents, drying techniques, solvents, precursor, aging time etc. have also been deliberated. These MSNPs are suitable for a variety of applications viz., in the drug delivery systems, high performance liquid chromatography (HPLC), biosensors, cosmetics as well as construction materials. The applications of these SNPs have also been briefly summarized. 相似文献
8.
A Facile Approach to Optically Active Hydroquinoline‐2‐carboxylates by a One‐Pot Asymmetric Michael/Transamination/Cyclization Process
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Dr. Chao Rong Hongjie Pan Dr. Mao Liu Hua Tian Dr. Yian Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):2887-2891
An efficient one‐pot synthesis of optically active hydroquinoline‐2‐carboxylates from 1,3‐cyclohexanediones, β,γ‐unsaturated α‐keto ester, and benzylamine in the presence of a chiral base catalyst and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) with good diastereoselectivity and high enantioselectivity is described. The reaction proceeds by a sequential asymmetric Michael/transamination/cyclization process. 相似文献
9.
Lok Kumar Shrestha 《Journal of Dispersion Science and Technology》2013,34(8):1236-1241
We have investigated the phase behavior of diglycerol monomyristate (DGM) in a variety of organic solvents over a wide range of temperatures and compositions. At lower temperature, there exists a surfactant solid, which solubilize different amounts of oils depending on the oil nature. The melting temperature of the solid phase is virtually constant in a wide range of composition. In all the systems, a lamellar liquid crystal (Lα) is formed in surfactant‐rich regions at intermediate temperatures between the solid‐melt and isotropic two‐ or single‐phase regions. In the dilute regions reverse vesicles are formed in the Lα+O regions mainly in the case of linear hydrocarbon type oils. In the aromatic and cyclic aliphatic oils, there are isotropic solutions at 25°C. However, there is dispersion of α‐solid in the case of liner hydrocarbon oils. Two liquid‐phase regions above the Lα phase are observed in the case of tetradecane and hexadecane. In the shorter chain oil systems, such as octane and decane, no two liquid‐phase appear above Lα region. That is the two liquid‐phase region is largely dependent on the chain length of the oils, and becomes wider in longer hydrocarbon oil. 相似文献
10.
Jin‐Chul Kim Hyeon Yong Lee Seung Lok Hwang In Ho Lee M.‐J. Moon‐Jeong M.‐J. Rang 《Journal of Dispersion Science and Technology》2013,34(5):697-701
Two kinds of topical dosage forms of hinokitiol (HKL), namely vesicles and oil‐in‐water (O/W) emulsions, were prepared. Behenyl trimethylammonium chloride (BTMAC) and fatty acids were used as bilayer‐forming materials of the vesicles, and oils were employed as oil phases of the emulsions. The substantivity of HKL in the preparations was evaluated in vitro using hairless mouse skins. After applying the preparations onto the skin and rinsing it, the amount of HKL left on the skin was determined using high performance liquid chromatography (HPLC). It was higher when HKL was encapsulated in cationic vesicles rather than in nonionic vehicles, emulsions. An ionic interaction between the cationic vehicle and negatively charged skin is likely to account for the high substantivity. Among the emulsion preparations, an emulsion having octyl salicylate as oil phase exhibited the highest substantivity of HKL. This is probably because that the oil is a good solvent for HKL and it is skin‐retentive. In vivo hair growth‐promotion effect of each dosage form was investigated, where the sample application onto the clipped backs of female mice (C57BL6) and the subsequent rinsing of the backs were done once a day for 30 days. Only HKL in the cationic vesicles had hair growth promotion effect, possibly due to the significant substantivity. 相似文献