磺酰胺类常咯啉分子力学参数的确定

应用量子化学ＭＮＤＯ程序及分子力学ＭＭＲ２程序，了一些未知磺酰胺类常咯啉的分子力学参数。应用这些参数计算了几个晶体结构已知的磺酰胺类化合物，与真实结构比较，计算结果令人满意。由此说明确定的分子力学参数且于计算磺酰胺类化合物时的正确性和可行性。     

过渡金属催化的芳环磺酰胺化反应研究进展

N-芳基磺酰胺骨架广泛存在于具有生物活性的分子中,在医药领域有十分重要的应用.因此研究N-芳基磺酰胺类化合物的合成方法受到了人们的广泛关注.近年来过渡金属催化的卤代芳烃、芳基硼酸和CAr—H键的磺酰胺化反应得到了快速发展,为N-芳基磺酰胺类化合物的合成提供了高效、绿色的方法.按照芳基源、过渡金属催化剂、配体和磺酰胺化试剂进行分类,综述了过渡金属催化的芳环磺酰胺化反应的最新研究进展,并对此类反应的研究方向进行了展望.     

高价碘试剂促进的N-芳基磺酰胺类化合物脱芳基反应（英文）

通过高选择性惰性磺酰胺芳基C—N键裂解反应,发展了一种Dess-Martin氧化剂(DMP)促进的N-芳基磺酰胺的脱芳基的方法.该无金属参与的反应在温和的条件下进行,可提供各种在生物学上有重要应用价值的伯磺酰胺类化合物,其中某些磺酰胺使用传统的氨解和水解方法难以获得.这一简单有效的脱芳基反应可在无金属催化剂条件下使芳基作为磺酰胺类化合物的氨基保护基.     

以ALS为靶标的新型除草剂的分子设计、合成及生物活性──IX.磺酰脲类和三唑并嘧啶-2-磺酰胺类ALS抑制剂的比较分子力场分析

采用比较分子力场分析方法研究了磺酰脲和三唑并嘧啶－２－磺酰胺类除草剂的三维定量结构活性关系，发现分子周围的立体场和静电场对化合物的除草活性有重要的影响．在对上述两类化合物进行成功叠加的基础上，进一步将两类化合物放在一起进行了比较分子力场分析，结果表明这两类化合物与受体间的相互作用具有共同的结合区域．     

新磺酰脲类化合物的合成、结构及其构效关系研究（Ⅳ）──合成及活性

合成了１７个在结构上具有一定递变规律的新磺酰脲类化合物，经元素分析、￣１ＨＮＭＲ和ＩＲ确定了其结构。讨论了该类化合物的分子及晶体结构特征。测定了所合成化合物的除草活性，并讨论了活性规律。     

NMR和分子力学法研究溶液中有机分子结构

在分子力学能量优化项中加入由ＮＭＲ实验得到的几何参数二面角（相应于~３Ｊ_（ＨＨ）耦合常数）及质子间距所构造的约束函数，使分子力学计算得到的能量极小点的分子构象，其耦合常数（~３Ｊ_（ＨＨ））及质子间距同ＮＭＲ实验结果相符合。文中以（±）－３－（４＇－甲苯基）－１－氮杂双环［２．２．２］－３－辛醇为例，采用自编的ＮＭＲ参数约束的分子力学计算程序ＭＭ２ＮＪ对其构象进行了计算。所得结果与Ｘ射线衍射法比较，有较好的一致性     

以ALS为靶标的新型除草剂的分子设计、合成及生物活性--Ⅸ. 磺酰脲类和三唑并嘧啶-2-磺酰胺类ALS抑制剂的比较分子力场分析

采用比较分子力场分析方法研究了磺酰脲和三唑并嘧啶-2-磺酰胺类除草剂的三维定量结构活性关系, 发现分子周围的立体场和静电场对化合物的除草活性有重要的影响. 在对上述两类化合物进行成功叠加的基础上, 进一步将两类化合物放在一起进行了比较分子力场分析, 结果表明这两类化合物与受体间的相互作用具有共同的结合区域.     

IPrAuCl/AgOTf催化下合成N-磺酰基四氢吡咯类化合物

在IPrAuCl和AgOTf催化体系作用下,通过一系列磺酰胺和四氢呋喃类化合物反应,合成了N-磺酰基四氢吡咯类化合物,实现了五元氧杂环到氮杂环类化合物的转换.     

新型线粒体氧还酶抑制剂型分子探针: 叠氮水杨酰胺类化合物的合成

以硝基水杨酰胺经还原，重氮化，叠氮化反应合成了五个新的叠氮水杨酰胺类化合物。通过还原反应的研究发现，侧链较短的硝基水杨酰胺用Sn+HCl还原效果较好。侧链较长的硝基水杨酰胺用H~2-Pd/C催化加氢还原效果较好。产品结构经IR，^1H NMR，MS和元素分析确定。合成的新叠氮水杨酰胺类化合物可以作为线粒体呼吸链酶的抑制剂型分子探针。     

18-冠醚-6的构象研究

以柔性大分子１８－冠醚－６为研究对象，将ＭＮＤＯ法所得的三种构象的静电势电荷用于分子力学计算，得到了三种构象的能量，同时计算了电负性电荷，亦将其用于分子力学计算，将两种计算结果进行比较发现，有可能将电负性作为分子力学、分子动力学计算的力场参数。     

硫杂冠醚铜(Ⅱ)配合物构象和性质的分子力学研究

用经改进的分子力学方法MPM对一系列硫杂冠醚铜（Ⅱ）配合物进行了研究．对它们的构象和能量的分子力学计算结果表明，在这类配合物中，五员鳌环比六员鳌环稳定，随冠醚环大小和分子内张力的变化，其配合物的结构和性质有规律地变化     

Molecular mechanics (MM3) calculations on conjugated hydrocarbons

The MM3 molecular mechanics program has been extended to conjugated systems. A VESCF method is applied to the pi-system to calculate bond orders, from which various stretching and torsional parameters are obtained. The procedure gives somewhat better results than the analogous MM2 calculations. It has been applied to a study of 81 compounds of aromatic and other conjugated hydrocarbons, as well as 45 alkenes and unconjugated polyenes. The structures calculated are generally in good agreement with experiment, and the heats of formation of these compounds can be calculated with a rms value of 0.62 kcal/mol, which may be compared with the average experimental error of 0.61 kcal/mol. In addition, vibrational frequencies for five representative conjugated model structures are calculated, with an rms value of 46 cm^?1, and from these, other properties such as entropy can be calculated.     

顺式环十二碳烯的构象

用分子力学法(MMX程序)计算了15-苯基双环[10,3,0]十五碳-1(12)-烯-13-酮,其分子中环十二碳烯部分的构象为能量最低的[l_(ene)2333],与X衍射结果吻合.同时,还计算了15个顺式环十二碳烯的构象,求出了它们的能量及结构参数,讨论了影响构象稳定性的因素.     

Empirical relationship between structure and molecular optical rotation in six-membered cyclic compounds

The molecular optical rotation of a six-membered series of cyclic compounds has been calculated with a simple method which relates the sign and magnitude of the molecular optical rotation to the geometry, conformation and absolute configuration of the studied compounds. The optimised geometry of each conformer was calculated by molecular mechanics calculations. The values obtained seem to confirm the existence of a close relationship between the value of molecular optical rotation of a compound and its geometry.     

Theoretical study of some nitrososulfamide compounds with antitumor activity

The lowest-energy conformations of four 2-chloroethylnitrososulfamides were determined using the MM+ molecular mechanics method as implemented in Hyperchem 6.0. Some of the calculated structural parameters, angles and bonds lengths were compared with the crystal structure data of N-nitroso-N-(2-chloroethyl)-N'-sulfamoyl- proline. Using MM+, AM1 and PM3 the anti conformation was predicted to be more stable than the syn conformation in each of these compounds. With these methods we found that the relative energy of the transition state (TS) was considerably higher, but with the ab initio method using RHF with minimal basic function STO-3G we found that the syn conformation is predicted to be slightly more stable. The determination of some atomic charges of a selection of atoms on the syn, anti and TS structures of the various compounds provided some details about the nature of the transition state.     

Development of glycyl radical parameters for the OPLS-AA/L force field

On the basis of quantum chemical calculations C(alpha)-glycyl radical parameters have been developed for the OPLS-AA/L force field. The molecular mechanics hypersurface was fitted to the calculated quantum chemical surface by minimizing their molecular mechanics parameter dependent sum-of-squares deviations. To do this, a computer program in which the molecular mechanics energy derivatives with respect to the parameters were calculated analytically was developed, implementing the general method of Lifson and Warshel (J Chem Phys 1968, 49, 5116) for force field parameter optimization. This program, in principle, can determine the optimal parameter set in one calculation if enough representative value points on the quantum chemical potential energy surface are available and there is no linear dependency between the parameters. Some of the parameters in quantum calculations, including several new torsion types around a bond as well as angle parameters at a new central atom type, are not completely separable. Consequently, some restrictions and/or presumptions were necessary during parameter optimization. The relative OPLS-AA energies reproduced those calculated quantum chemically almost perfectly.     

分子模型及其在手性识别机理研究上的应用

介绍了近十几年来在色谱手性识别机理研究中的分子模型。在这些模型中,采用量子力学、分子力学和分子动力学等方法计算了手性选择试剂与对映体之间的相互作用,并借助X射线晶体学、核磁共振技术和计算机模拟等技术建立了各种分子模型,研究在手性化合物分离过程中的手性识别机理。     

PEFF: A program for the development of empirical force fields

PEFF is a new computer program designed to assist in the development of empirical force fields used in molecular mechanics calculations. Its main features are: constrained and unconstrained energy minimization available with four different techniques, rigid group refinement, crystal lattice summations, calculation of normal modes, thermodynamic functions and crystallographic temperature factors, vibrational corrections of calculated crystal structures, and a multidimensional driver to scan the energy hypersurface. Used in force field optimization mode, the program employs a least-squares method to fit the force field parameters to a set of experimental data.