共查询到20条相似文献，搜索用时 12 毫秒
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Cao X Zhou J Zou Y Zhang M Yu X Zhang S Yi T Huang C 《Langmuir : the ACS journal of surfaces and colloids》2011,27(8):5090-5097
Switchable supramolecular self-assemblies on the basis of interaction between melamine group containing photochromic diarylethene unit (DTE) and naphthalimide derivate (1) were designed and fabricated. 1 can gelate several aprotic solvents with different morphologies. The gel turned into partial gel in ethyl acetate with the addition of DTE as a guest molecule. Both the absorption and fluorescence spectra of the assembly can be reversibly switched by alternating UV/visible light irradiation. Meanwhile, the morphology of the coassembly of 1(2)·DTE changed to film from original pieces of gel 1 in ethyl acetate. When 1(2)·DTE was irradiated by UV light, the film morphology was converted into aggregated flakes. Moreover, the surface wettability of the complex can also be switched by light irradiation. The photochromic diarylethene unit is able to modulate the fluorescence and morphology of the assembled system only by virtue of light irradiation. Therefore, these results provide further insights into fluorescence and morphology controlling, especially application in upscale smart responsive materials. 相似文献
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Abderahmane Belafriekh Francesco Secundo Stefano Serra Zeineddine Djeghaba 《Tetrahedron: Asymmetry》2017,28(3):473-478
The effects of two eco-friendly solvents, 2-methyltetrahydrofuran (MeTHF) and cyclopentyl methyl ether (CPME), on the enzyme activity and enantioselectivity of Novozym 435, Candida rugosa lipase (CRL), Porcine pancreas lipase (PPL), Lipase AK, Lipase PS, and Lipozyme, a series of commercial lipases, in the enantioselective transesterfications of racemic menthol, racemic sulcatol and racemic α-cyclogeraniol were studied. Vinyl acetate was chosen as the acyl donor and the reactions were carried out at water activity 0.06. The activity of lipases in CPME was similar to that observed in other largely employed organic solvents [toluene and tert-butyl methyl ether (MTBE)], and was slightly lower in MeTHF. However, for most of the lipases tested, the enantioselectivity was higher in the eco-friendly solvents. Lipase AK exhibited a high enantioselectivity (E = 232) for the resolution of racemic menthol but the reaction rate was low. Lipase formulation (the enzyme was frozen and lyophilized in potassium phosphate buffer without and with 5% (w/v) of sucrose, d-mannitol, or methoxy poly(ethylene glycol)) was tested with this lipase in order to improve its activity, which increased up to 4.5 times, compared to the untreated enzyme. CALB was found to be a useful biocatalyst for the resolution of racemic sulcatol, where high activity and enantioselectivity were obtained (E ≥ 1000). For the resolution of the racemic primary alcohol α-cyclogeraniol, most of the lipases tested were active but not enantioselective, except lipase PS which displayed a moderate enantioselectivity (E = 19). The effect of the presence of a low percentage of two ionic liquids (ILs) 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]) (5% (v/v)) and 1-Butyl-3-methylimidazoliumtetrafluoroborate ([BMIM][BF4]) (1% (v/v)) in the medium was also investigated. Only in the case of CRL the ILs slightly increased the enantioselectivity from E = 91 to E = 103 and E = 120 for [BMIM][TFSI] and [BMIM][BF4], respectively. However, in all cases ILs caused a decrease of enzyme activity. 相似文献
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Stanley N.S. Vasconcelos Joel S. Reis Isadora M. de Oliveira Michael N. Balfour Hélio A. Stefani 《Tetrahedron》2019,75(13):1865-1959
Since the development of the Ullmann coupling in the early 20th Century, there has been intense and continuous research on the syntheses of biaryl compounds, which appears as an interesting branch of organic chemistry.A myriad of methodologies for the synthesis of biaryl compounds have been studied and well established, including homocoupling methodologies, which in general are robust as well as consolidated strategies. Biaryl systems are quite relevant building blocks for the synthesis of more complex chemical structures. Besides the diversity of functional groups that can be used to promote a new aryl-aryl bond, there is a wide variety of transition metals that can act as catalyst in these processes.In this review, we summarized numerous methodologies of homocoupling reactions for the synthesis of symmetrical biaryl compounds. 相似文献
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Alexander S. Alekseev Ivan N. Domnin Artem B. Ivanov Nadezhda A. Tereschenko 《Mendeleev Communications》2018,28(4):409-411
The effect of prolonged UV irradiation and high temperature on a blue phase polymer film prepared by the Langmuir–Schaefer method based on 11-hydroxyundeca-6,8-diyn-1-yl N-(4-methoxyphenyl)carbamate was evaluated. The high stability of the polymer under extreme external influences was revealed. The transition of a monolayer to a bilayer with increasing surface pressure during the Langmuir layer formation was confirmed by atomic force microscopy. 相似文献
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Jianqing Li Daniel Smith Subramaniam Krishnananthan Dauh-Rurng Wu Dawn Sun Peng Li Kristen Ryan Min Hu Wenge Cui Jennifer Naginskaya Shuang Liu Paul C. Lobben Alicia T. Ng Richard Olson Arvind Mathur 《Tetrahedron: Asymmetry》2017,28(1):196-202
BMS-911278 was identified as a potent triple reuptake inhibitor potentially useful for the treatment of depression. The original racemic synthesis suffered from tedious and low recovery resolution and HPLC separation, as well as low-yielding hazardous N-demethylation at the API step. To support further preclinical studies, a scalable enantioselective synthesis was developed. Herein, we report an efficient asymmetric synthesis of BMS-911278 featuring two key steps: an enantioselective Miyaura reaction and an intramolecular regioselective cyclization. 相似文献