Wittig-Horner 反应合成维A酸酯的改进方法

改进了Wittig-Horner反应合成维A酸酯的方法,利用3-甲基5-(2,6,6-三甲基-1-环已烯-1-基)-1,3(或1,4)-戊二烯膦酸二烷基酯直接与五碳醛反应合成目标产物,省掉了碱催化下的双键重排反应。将含有C^1末端双键的膦酸二烷基酯直接用于wittig-Horner反应。     

Asymmetric Cyclopropanation Catalyzed by Four Stereoisomers of a Copper-(Schiff-base) Complex with Double Chiral Centers

Catalytic asymmetric cyclopropanation of diazoacetates with olefins has attracted much attention. Those catalysts containing various metals and optically active ligands have been employed for this reaction1,2. The first catalytic asymmetric cyclopropanation reaction was reported in 1966 by Nozaki et al.3. The author used the copper(II) complex 1 bearing a salicyladimine ligand as catalyst though with a low e.e. value of 6%. Aratani and his coworkers designed the copper-(Schiff-base) comp…     

LIMIT CYCLES AND BIFURCATION CURVES FOR THE QUADRATIC DIFFERENTIAL SYSTEM(III)_(m=0)HAVING THREE ANTI-SADDLES(II)

ＬＩＭＩＴＣＹＣＬＥＳＡＮＤＢＩＦＵＲＣＡＴＩＯＮＣＵＲＶＥＳＦＯＲＴＨＥＱＵＡＤＲＡＴＩＣＤＩＦＦＥＲＥＮＴＩＡＬＳＹＳＴＥＭ（ＩＩ）ｍ＝０ＨＡＶＩＮＧＴＨＲＥＥＡＮＴＩＳＡＤＤＬＥＳ（Ｉ）ＹＥＹＡＮＱＩＡＮＡｂｓｔｒａｃｔＡｓａｃｏｎｔｉ...     

空间矩和Zernike矩亚像素边缘算子分析

讨论了空间矩、Zernike矩两个亚像素边缘算子的运行时间和定位精度。分析结果表明,Zernike具有更快的运行速度,当计算3个用于边缘定位的参数时,其运行时间较空间矩算子节约了50%。理论分析了空间矩和Zernike矩算子的关系,并推导出了两个算子边缘距离为l的差值公式。测试结果表明,当两个算子的l都限制在中心像素内时,空间矩算子的边缘厚度多达3个像素,而Zernike矩算子的边缘厚度小于1个像素,可见Zernike矩算子的定位精度为真正的亚像素级。经比较,Zernike矩算子的运行时间和定位精度均好于空间矩算子。     

Synthesis and Crystal Structure of α-( N-Protected a mino)β- lactam Derivative of 1 ,5-Benzothiazepine

１　ＩＮＴＲＯＤＵＣＴＩＯＮＲｅｃｅｎｔｌｙ,ａｎｕｍｂｅｒｏｆｄｅｒｉｖａｔｉｖｅｓｏｆｂｅｎｚｏｔｈｉａｚｅｐｉｎｅｈａｖｅｂｅｅｎｐｒｅｐａｒｅｄａｎｄｓｔｕｄｉｅｄｆｏｒｔｈｅｉｒｐｈａｒｍａｃｏｌｏｇｉｃａｌａｃｔｉｖｉｔｉｅｓ〔１５〕．Ｉｎｏｕｒｐｒｅｖｉｏｕｓｗｏｒｋ,ｗｅｈａｖｅｉｎｃｏｒｐｏｒａｔｅｄｔｈｅβｌａｃｔａｍｒｉｎｇｉｎｔｏ１,５ｂｅｎｚｏｔｈｉａｚｅｐｉｎｅｂｙｒｅａｃｔｉｏｎｏｆ１,５ｂｅｎｚｏｔｈｉａｚｅｐｉｎｅｗｉｔｈｓｏｍｅａｃｙｌｃｈｌｏｒｉｄ…     

Synthesis and Crystal Structure of Dicesium trans Dicarbonatotetraaquomagnesium, Cs_2[Mg(CO_3)_2(H_2O)_4]

ＩｎｔｒｏｄｕｃｔｉｏｎＰｒｅｖｉｏｕｓｌｙ,ｗｅｒｅｐｏｒｔｅｄｔｈｅｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｏｆＫ２［Ｎｉ（ＣＯ３）２（Ｈ２Ｏ）４］［１］,ｗｈｉｃｈｃｒｙｓｔａｌｌｉｚｅｄｉｎｔｈｅｂａｙｌｉｓｓｉｔｅｔｙｐｅｓｔｒｕｃｔｕｒｅａｎｄｗａｓｆｏｕｎｄｔｏｂｅｉｓｏｓｔｒｕｃｔｕｒａｌｗｉｔｈＫ２［Ｃｏ（ＣＯ３）２（Ｈ２Ｏ）４］［２］ａｎｄＫ２Ｍｇ（ＣＯ３）２·４Ｈ２Ｏ［３］．Ｉｎｏｒｄｅｒｔｏｓｙｓｔｅｍａｔｉｃａｌｌｙｉｎｖｅｓｔｉｇａｔｅｔｈｅｏｃｃｕｒｒｅｎｃｅｏｆｔｈｅｃｏ…     

三甲川菁染料敏化TiO2纳米 结构电极的光电化学

The photoelectrochemical behaviors of the TiO₂ nanostructured porous film sensitized by cyanine dye were investigated in this paper.The results showed that the excitaed state level matched the conduction band edge of TiO₂ nanoparticle.Therefore the sensitization of the dye can increase the photocurrent intensity of the TiO₂ nanostructured electrode obviously and results in a red-shift of optical absorption from the ultra-violet region to the visible.As a result,the light-to-electricity conversion efficiency was improved evidently,the maximum value of IPCE has reached 12.1%.     

A Fluorescence Optical Fiber Sensor for Amrinon Using a New Oxazole Compound

ＩｎｔｒｏｄｕｃｔｉｏｎＡｍｒｉｎｏｎ,ａｓｙｎｔｈｅｔｉｃｂｉｐｙｒｉｄｉｎｅｄｅｒｉｖａｔｉｖｅ,ｎｏｎｇｌｙｃｏｓｉｄｅａｎｄｎｏｎｃａｔｅｃｈｏｌａｍｉｎｅｃａｒ－ｄｉｏｔｏｎｉｃｓｔｉｍｕｌａｎｔ,ｉｓｃｕｒｒｅｎｔｌｙｕｓｅｄｉｎｔｈｅｔｒｅａｔｍｅｎｔｏｆｔｈｅｈｅａｒｔｆａｉｌｕｒｅａｎｄｆｏｒｃａｒｄｉｏｖａｓｃｕ－ｌａｒｓｕｐｐｏｒｔｉｎｐｅｄｉａｔｒｉｃｐａｔｉｅｎｔｓ．Ｉｔｐｏｓｓｅｓｓｅｓｐｏｔｅｎｔｃａｒｄｉａｃａｎｄｂｌｏｏｄｖｅｓｓｅｌｓｐｒｅａｄｉｎｇｅｆ－ｆｅ…     

The Elastic Continuum Limit of the Tight Binding Model

The authors consider the simplest quantum mechanics model of solids,the tight binding model,and prove that in the continuum limit,the energy of tight binding model converges to that of the continuum elasticity model obtained using Cauchy-Born rule.The technique in this paper is based mainly on spectral perturbation theory for large matrices.