نتایج جستجو برای: chiral compounds

تعداد نتایج: 262114  

Journal: :Chemical communications 2006
Partha Pratim Bose Michael G B Drew Apurba K Das Arindam Banerjee

Intertwining triple helical nanofibers with an overall handedness have been formed from self-assembling chiral benzene-1,3,5-tricarboxamides , and , whereas the achiral benzene-1,3,5-tricarboxamide upon self-association gives rise to straight nanofibers without any twist and transmission electron microscopy images of chiral compounds clearly demonstrate that the handedness of the triple helical...

Journal: :Organic & biomolecular chemistry 2014
Shuang Yang Shou-Fei Zhu Na Guo Song Song Qi-Lin Zhou

A carboxy-directed asymmetric hydrogenation of α-alkyl-α-aryl terminal olefins was developed by using a chiral spiro iridium catalyst, providing a highly efficient approach to the compounds with a chiral benzylmethyl center. The carboxy-directed hydrogenation prohibited the isomerization of the terminal olefins, and realized the chemoselective hydrogenation of various dienes. The concise enanti...

2014
Yi Luan Jie Yu Xiaowei Zhang Scott E. Schaus Ge Wang

Diazo compounds, boranes, and acyl imines undergo a three-component Mannich condensation reaction under catalyst-free conditions to give the anti β-amino carbonyl compounds in high diastereoselectivity. The reaction tolerates a variety of functional groups, and an asymmetric variant was achieved using the (-)-phenylmenthol as chiral auxiliary in good yield and selectivity. These β-amino carbony...

Journal: :Chemical science 2017
Shiho Sairenji Takashi Kikuchi Mohamed Ahmed Abozeid Shinobu Takizawa Hiroaki Sasai Yuichiro Ando Kohsuke Ohmatsu Takashi Ooi Makoto Fujita

Determination of the absolute configuration of chiral tetra-substituted carbon centers is one of the most taxing steps in the enantioselective construction of this structural motif in asymmetric synthesis. Here, we demonstrate that the crystalline sponge method provides an effective way to crystallographically determine the absolute configuration of organic compounds bearing chiral quaternary c...

2013
I. Dierking W. Kuczynski

The cholesteric twist inversion by temperature variation of a single component thermotropic liquid crystalline system was experimentally investigated and is explained by the partial twisting power model, evaluating the temperature dependent pitch of five different configurations of a benzoic acid biphenyl ester with two chiral centers. The temperature dependence of the twisting power and the ch...

2012
Francesca Marini Silvia Sternativo

In the last ten years organocatalysis has emerged as an efficient and sustainable strategy for the asymmetric synthesis of chiral molecules. Optically active intermediates for novel interesting transformations are generated under mild and operationally simple conditions when selenium-containing compounds are used as reaction partners. The peculiar reactivity of organoselenium compounds has been...

2008
Song Xiang Huidong Zhang Peng Liu Changhao Wang

Chiral catalysis is of great industrial interest for the production of enantiomerically pure compounds. Although many homogeneous chiral catalysts have been developed, the difficulty of the product purification and catalyst recycle is one of the obstacles of the practical applications. The design and synthesis of efficient and recyclable heterogeneous chiral catalysts remain the challenges and ...

Journal: :amirkabir international journal of electrical & electronics engineering 2015
a.n. askarpour y. zhao a. alù

an important property of electromagnetic fields, which arises from the interaction between fields and chiral molecules, is called optical chirality. by enhancing this field property, while maintaining constant input power, we are able to increase absorption of circularly polarized light by chiral molecules of a certain handedness. this enhancement is achieved through the use of achiral plasmoni...

Journal: :Chemical & pharmaceutical bulletin 2011
Chuanzhu Gao Shaohua Gou Gang Xu

Eight platinum(II) compounds with a new chiral ligand, 2-(((1R,2R)-2-aminocyclohexylamino)methyl)phenol (HL), were designed, prepared and spectrally characterized. All compounds showed better aqueous solubility than cisplatin and oxaliplatin. In vitro cytotoxicity of these compounds against human HepG-2, MCF-7, A549 and HCT-116 cell lines was evaluated. Results indicated that all compounds show...

Karim Ghafouri, Sajjad Sedaghat, Samira Arab-salmanabadi

Spiro compounds are of interest due to their interesting conformational features and their structural implications on biological systems. The asymmetric characteristic of the molecule due to the chiral spiro carbon is one of the important criteria of the biological activities. These structures are a widespread structural motif found as key elements of numerous drugs and designed medicinal agent...

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