STUDIES ON DERIVATIVES OF 2,3-DIHYDRO-4H-1,3,2-BENZOXAZAPHOSPHORINE——SYNTHESIS AND STRUCTURE ANALYSIS OF 2,3-DISUBSTITUTED-2,3-DIHYDRO-4H-1,3,2-BENZOXAZAPHOSPHORIN-4-ONE-(THIONE)-2-SULFIDE(OXIDE)

A series of novel organocyclophosphorus compounds including twenty-three 2, 3-disubsti-tuted-2,3-dihydro-4H-1,3,2-benzoxazaphosphorin-4-one-2-sulfide (compounds Ⅰ) and three 2, 3-disubstituted-2,3,-dihydro-4H-1,3,2-benzoxazaphosphorin-4-thione-2-oxide (compounds Ⅱ) havebeen synthesized. Their structures were determined by IR, UV, HNMR, X-ray diffractionand elemental analysis. Each of compounds Ⅰ showed a strong absorption between 1290-1319em~(-1) in the IR spectrum. Comprehensive studies of the spectral data and experimental re-sults indicated that this strong characteristic absorption is different from that of the P = Olinkage and thus could be considered as a result of the stretching vibration of (unsaturatedC)-N single bond. In the course of synthesis of the compounds, an abnormal productisomers could be made predominantly in yield and be readily isolated from the other byrecrystallizing for several times from appropriate solvent. Data for the melting point, IR,UV and HNMR spectra of three pairs o     

杂氮硅三环化合物(Ⅰ)和(Ⅱ)晶体结构的研究

杂氮硅三环化合物Ⅰ和的分子结构用直接法解,经全矩阵最小二乘修正,得到它们的晶体学参数。并对它们的结构进行了比较和讨论。     

脱氧异氢化青嵩乙素的晶体结构测定

脱氧异氢化青蒿乙素的晶体属于单斜晶系,空间群为P2_1,晶胞参数α=16.262,b=8.304,c=10.679A,β=108.08°,晶胞内分子数Z=4,D_c=1.519g·cm~(-3)。用MULTAN-78测定其分子粗结构模型,通过块对角矩阵最小二乘法进行修正,最后R=0.073。根据原子在三维空间的分布,确定分子中两个六元环为顺式联接,结构如下式所示:     

天花粉蛋白分子的三维结构

本文报道了我们最近建立的单斜晶胞内一个不对称单元中两个天花粉蛋白分子的模型,指出蛋白分子结构可以划分为大小两个结构域以及二级结构的一些特点,描述了独立单元中以一种非对称方式相关联的两个蛋白分子的差异及其相互作用,并解释了重原子衍生物的结合位置。     

1.73分辨率天花粉蛋白晶体中的水结构

本文报道的天花粉蛋白晶体中水的结构模型,包括了133个水分子,其中118个同蛋白的原子成氢键。天花粉蛋白内部有4个分立的水分子,其中2个水分子W251和W252分剔与A5螺旋变形部位的残基156Gln和157Ser的侧链成氢键,对维持活性部位的构象有贡献。晶体中水结构的比较结果表明,核糖体接近蛋白时,会诱导蛋白活性部位残基的构象发生变化,使各催化基团按催化效果最佳的构象排布,并激活一个水分子(W257)直接参与核糖体失活作用。     

苯骈-1-氧-2-磷-3-氮杂环己烷衍生物的研究——2,3-二取代苯骈-1-氧-2-硫(氧)化磷-3-氮杂环己-4-(硫)酮的合成及结构分析

本文合成了23个2,3-二取代苯骈-1-氧-2-硫化磷-3-氮杂环已-4-酮(化合物Ⅰ)和3个2,3-二取代苯骈-1-氧-2-氧化磷-3-氮杂环已-4-硫酮(化合物Ⅱ)新的有机环磷化合物,并用红外吸收光谱、氢核磁共振谱、紫外吸收光谱、X射线衍射分析和元素分析等方法鉴定了它们的组成和结构.并研究了23个化合物Ⅰ的红外吸收光谱,发现它们在指纹区1290—1319cm~(-1)范围内均有强吸收峰.经综合分析各光谱数据和实验结果,肯定了此强峰与P=O基因吸收峰的区别,并确认为不饱和碳原子C—N键伸缩振动所造成的特征吸收。 在合成上述化合物的过程中,往往在反应溶液中得到“正常产物”Ⅰ及其同分异构体“异常产物”Ⅱ 的混合物.通过选择适宜的缩合条件,可使其中某一异构体成为主要产物,并可在合适的溶剂中经多次重结晶将它们分离.本文提供了三对此类同分异构体的融点、红外吸收光谱、紫外吸收光谱和氢核磁共振谱等方面的数据,并对各谱图作了初步解析。     

STUDIES ON ORGANOMETALLIC COMPOUNDS OF TITANIUM,ZIRCONIUM AND HAFNIUM——THE CRYSTAL AND MOLECULAR STRUCTURES OF OXO-BRIDGED TETRAKIS(CYCLOPENTADIENYL)BIS (o.TOLYL)AND TETRAKIS(METYLCYCLOPEN-TADIENYL) BIS(p-TOLYL)BINUCLEATED ZIRCONIUM COMPOUNDS

This paper reports the crystal and molecular structures of tetrakis (cyclopentadienyl) bis(o-tolyl)-μ-oxo-dizirconium [dimer (Ⅰ)] and tetrakis (methylcyclopentadienyl) bis (p-tolyl)-μ-oxo-dizirconium [dimer (II)]. Both of them belong to monoclinic system and possess the same spacegroup C_2~5h- 2_1/a. The cell dimer (Ⅰ) containing four molecules is defined by a=19.122A,b=16.319A, c = 9.296A, β= 92°1′; the cell dimer (Ⅱ) containing two molecules is defined bya = 20.076A, b = 8.205A, c = 10.016A, β= 104°41′. The important difference of molecular configurations between the two dimers lies in thatthe dimer (Ⅰ) has no symmetry center and its Zn-O-Zr oxo-bridge presents a slightly bentconfiguration while the dimer (Ⅱ) takes the oxgen atom as a symmetry center and its oxo-bridge present linear linkage. In accordance with the above-mentioned molecular configuration, steric effect and elec-tronic structure have been further discussed.     

苯骈-1-氧-2-磷-3-氮杂环己烷衍生物的研究——2,3-二取代苯骈-1-氧-2-硫(氧)化磷-3-氮杂环己-4-(硫)酮晶体结构和分子结构的测定

C_(17)H_(17)N_2O_2Cl_2PS(NP-8)和C_(17)H_(19)N_2O_2PS(NP-10-II)两个晶体结构是用帕特逊法测定的,它们均属单斜晶系,空间群分别为P2_1/a和P2_1/n.单胞中有四个分子.晶胞参数分别为:a=26.622(7)A,b=7.711(2)A,c=9.461(3)A,β=94.90°(4);a=18.897(3)A,b=10.199(13)A,c=8.948(3)A,β=94.30°(3).经块对角矩阵最小二乘法修正,对NP-8晶体的全部2971个衍射点,偏离因子R=0.046;对NP-10-II 晶体的 1711(I)>3σ(I)衍射点,偏离因子 R=0.076. 文中根据NP-8和 NP-10-II的分子结构,合理地解释了光谱数据,并对结构特点进行了讨论。     

A DETERMINATION OF THE THREE-DIMENSIONAL STRUCTURE OF TRICHOSANTHIN AT LOW RESOLUTION

Trichosanthin, extracted from a Chinese herb medicine, is a plant protein having a molec-ular weight of ca. 24,000 and containing 219 amino acid residues. The crystal is mono-clinic, belonging to the space group C2, with the following cell dimensions: a=75.64A, b=75.52A, c=88.85A β= 99.51°. Each asymmetric unit contains two such protein molecules. The UO_2Ac_2 and K_2Pt(NO_2)_4 derivatives of trichosanthin have been prepared by soakingin the respective solutions of high dilution. The joint probability of isomorphous replacementand anomalous scattering has been used to calculate the native phases. In the electron densitymaps, the boundary between the two protein molecules can be recognized, leading to thefollowing approximate molecular dimensions: 45×40×35A~3. Each molecule contains fourrod-shaped segments easily known as α-helices.