نتایج جستجو برای: unsymmetrical

تعداد نتایج: 1532  

Journal: :Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2010
Qianfu Luo Yi Liu Xin Li He Tian

Three symmetrical and unsymmetrical trans-dithienylethenes functionalized with pyridines and fluorenes have been synthesized by a facile one-pot procedure, and their characteristics and photochromism were investigated. Their fluorescent intensity was efficiently regulated by a photochromic switch using alternative irradiation with UV light and visible light. Moreover, by protonation and complex...

Journal: :Organic letters 2011
Xingwang Zheng Jinchang Ding Jiuxi Chen Wenxiao Gao Miaochang Liu Huayue Wu

The coupling of arylboronic acids with electron-deficient nitroarenes was realized for the first time by using a rhodium(I) catalyst under an air atmosphere, achieving unsymmetrical diaryl ethers with yields ranging from poor to good. From a deuterium labeling experiment, the oxygen atom is derived from ambient water. The efficiency of this reaction was demonstrated by its compatibility with fl...

Journal: :Chemical communications 2014
Shuanglong Lu Jiaqing Wang Xueqin Cao Xinming Li Hongwei Gu

A new one-pot method has been developed for the selective synthesis of secondary amines via reductive amination of the corresponding nitriles using Pt nanowires as a catalyst. This method allows for the synthesis of both unsymmetrical and symmetrical secondary amines in excellent yields (up to 95%) in the presence or absence of additional amines, respectively. Furthermore, the reaction proceeds...

2008
Chunbao Miao Changsheng Yao Shujiang Tu Xiaoqiang Sun

The title compound, C(28)H(28)N(2)O(5), consists of a partially hydrogenated acridine ring system with two substituted phenyl substituents on the dihydro-pyridine ring which are both nearly perpendicular to the mean plane of the acridine unit [dihedral angles of 81.3 (1) and 89.6 (1)° between the central ring of acridine and the methoxyphenyl and nitrophenyl rings, respectively]. The dihydro-py...

2014
Dattaguru V. Kamath

In this paper, a general two-admittance current-mode circuit structure using Dual-Output OTA (DO-OTA) is explored to derive new third-order unsymmetrical band-pass filters. The proposed circuits are attractive as they require less number of OTAs and use only grounded capacitors. The other advantageous features offered by proposed filters are ease of design, good sensitivity and orthogonal tunab...

Journal: :Chemical science 2014
Hongli Bao Liela Bayeh Uttam K Tambar

The 1,4-functionalization of dienes is a synthetically useful strategy for incorporating molecular complexity into a class of simple substrates. We report the aminoarylation of acyclic and cyclic 1,3-dienes via the sequential [4+2] cycloaddition with a sulfurdiimide reagent and copper-catalyzed allylic substitution with Grignard reagents. The regioselective and diastereoselective aminoarylation...

2014
KUO CHU HWANG PERIYASAMY MURUGAN

This paper reports the synthesis of nitrogen containing heterocyclic compounds such as quinoxalines (5-7), imidazoles (8, 9,10,11), aminothiazole (12), aminooxazole (13), aminoimidazole (14) and benzothiazine (17) from the reaction with unsymmetrical diketone 4, 3 and 4a respectively. The aforementioned compounds with 4-pyridyl,4fluorophenyl groups have different positions in their ring skeleto...

Journal: :Dalton transactions 2006
Robert C J Atkinson Vernon C Gibson Nicholas J Long Lara J West Andrew J P White

New unsymmetrical S/O 1,1'-disubstituted ferrocenediyl ethers and hydroxides have been synthesised. The coordination chemistry of 1-(methylsulfanyl)-1'-(methoxy)ferrocene has been investigated with palladium(II) and platinum(II) precursors. With palladium(II), a bis-mu-chloro-bridged dimeric complex was obtained with the ligand bound solely through the thioether donor group. With platinum(II), ...

Journal: :Annales UMCS, Informatica 2003
Marek M. Stabrowski

The research reported in this paper presents a new idea of the storage structure of sparse matrices. This structure is used in the multi-option solver of linear equation systems with unsymmetrical sparse coefficient matrices. The new solver is compared comprehensively with the analogous (identical numerical method used) solver of the classical type. The tests of new solver have been performed o...

2011
Brahim Boualy Mohamed Anoir Harrad Larbi El Firdoussi Mustapha Ait Ali Corrado Rizzoli

The title compound, C(11)H(14)Cl(2)O, was synthesized by the reaction of a dichloro-methane solution of (R)-carvone and potassium tert-butano-late in the presence of a catalytic amount of benzyl-triethyl-ammonium chloride in chloro-form. The cyclo-hexene ring adopts a half-boat conformation. The cyclo-propyl ring is unsymmetrical, the shortest C-C bond being distal to the alkyl-substituted C at...

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