共查询到16条相似文献,搜索用时 62 毫秒
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在药物设计中,化合物的流水性是值得考虑的一种重要的性质.目前常使用化合物在正辛醇和水两相间的分配系数的对数值(logP)来度量其流水性.仅从化合物的结构出发来预测其脂水分配系数具有重要的意义,已有多种计算方法见诸报导’‘,“.对于普通的有机化合物,它们能给出较好的结果.多肽是一类具有重要生物功能的化合物.在药物设计中,多肽也是常用的物系.目前预测一般有机化合物脂水分配系数的方法对于多肽尚不能给出满意的结果.鉴于多肽类化合物特殊的重要性,专门发展一种方法来预测多肽的脂水分配系数也是十分必要的.在这方… 相似文献
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A new method is presented for the calculation of octanol/water partition coefficients. On the basis of summation of atomic contributions, our algorithm, namely; XLOGP, also incorporate correction factors into the calculation. Multivariate regression analysis was performed on a training database of 1831 organic compounds with diverse structures to give the final model. The correlation coefficients for the whole set fitting is 0.968 and the standard deviation is 0.37. The result shows that our model is accurate enough for logP estimation in QSAR studies. Compared to other similar approaches, our method gives better results and is more convenient to use. 相似文献
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卤代芳烃的脂水分配系数与分子结构的定量关系 总被引:1,自引:0,他引:1
本文通过HMO法计算得到了46个卤代芳烃的部分量子化学参数,同时计算了它们的分子总表面积(TSA),以线性溶解能关系(LSER)理论为基础探讨了化合物的正辛醇/水分配系数与其分子结构间的定量关系,建立了一种良好的分配模型,该模型可准确计算出两种溶剂的表面张力之差。 相似文献
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脂肪胺的脂水分配系数与结构参数的关系 总被引:1,自引:1,他引:1
研究了脂肪胺的脂水分配系数实验值与半经验量子化学计算获得的理论计算参数值间的相关关系,结果表明:实验测定值与分子范德华体积及碳氮键长之间有良好的多元线性关系. 相似文献
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人工神经网络法预测核苷及核酸碱基的疏水分配系数 总被引:1,自引:0,他引:1
用人工神经网络方法预测核苷及核酸碱基一类化合物的lgP值,预测精度显著优于BlgP法和AlgP法,根据预测结果讨论了分子内氢健及分子构象柔顺性对这类化合物疏水性的影响。 相似文献
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应用半经验量子化学AM1方法得到了108种含氧有机分子的优势构象,利用AM1方法和分子图形学技术获得了它们的电子结构和几何结构参数,并将这些参数与脂水分配系数相关联,采用逐步回归分析方法,成功地建立了拟合度高、物理意义明确、预测能力强的含氧有机分子脂水分配系数-结构参数定量关系方程,找出了影响含氧有机分子脂水分配系数的主要结构因素. 相似文献
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用Benson基团加和法预测气相色谱保留值 总被引:3,自引:0,他引:3
应用Banson基团加和法,对氯代苯,脂肪醇两类化合物分子结构与气相色谱保留值间的关系进行了研究。对部分化合物的保留值做了预测,结果表明这两类化合敢相色谱保留值具有基团加和性,预测值与实验值吻合很好。 相似文献
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The chromatographic behavior of eight lanostanoid triterpenes, which are four pairs of C-3 epimers and two pairs of C-3/C-15 positional isomers, were determined by reverse-phase high performance liquid chromatography (RP-HPLC). In the mobile phase systems of acetonitrile-water-acetic acid, methanol-water-acetic acid, and tetrahydrofuran-water-acetic acid, these triterpenes showed a very good linear relationship between capacity factors (k′) and volume fractions of organic modifiers. The partition coefficients (Poet) of these triterpenes in 1-octanol/water and capacity factors (k′) in RP-HPLC, when both expressed in logarithm, correlated linearly. This study showed that RP-HPLC is an effective method to evaluate the molecular hydrophobicity of multi-functional compounds which are stereo- and positional isomers. 相似文献
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The preparation of new sulfonamide ligands derived from L-tartaric acid and camphor sulfonyl chloride are described. The employment in the titanium tetraisopropoxide-promoted enantioselective addition of diethylzinc to ketones has been studied. The best enantiomeric excess is up to 99% with 7 mol% catalyst loading at room temperature. 相似文献
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《合成通讯》2013,43(15):2635-2641
Abstract Convenient synthesis of uridine derivatives containing amino acid residues were carried out successfully by reacting triazolated uridine with the hydrochloride salts of some amino acid esters, which provides a general method for the direct introduction of amino acid group onto nucleoside residue. 相似文献
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Krishnayan Basuroy Vasantham Karuppiah Narayanaswamy Shamala Padmanabhan Balaram 《Helvetica chimica acta》2012,95(12):2589-2603
Backbone alkylation has been shown to result in a dramatic reduction in the conformational space that is sterically accessible to α‐amino acid residues in peptides. By extension, the presence of geminal dialkyl substituents at backbone atoms also restricts available conformational space for β and γ residues. Five peptides containing the achiral β2,2‐disubstituted β‐amino acid residue, 1‐(aminomethyl)cyclohexanecarboxylic acid (β2,2Ac6c), have been structurally characterized in crystals by X‐ray diffraction. The tripeptide Boc‐Aib‐β2,2Ac6c‐Aib‐OMe ( 1 ) adopts a novel fold stabilized by two intramolecular H‐bonds (C11 and C9) of opposite directionality. The tetrapeptide Boc‐[Aib‐β2,2Ac6c]2‐OMe ( 2 ) and pentapeptide Boc‐[Aib‐β2,2Ac6c]2‐Aib‐OMe ( 3 ) form short stretches of a hybrid αβ C11 helix stabilized by two and three intramolecular H‐bonds, respectively. The structure of the dipeptide Boc‐Aib‐β2,2Ac6c‐OMe ( 5 ) does not reveal any intramolecular H‐bond. The aggregation pattern in the crystal provides an example of an extended conformation of the β2,2Ac6c residue, forming a ‘polar sheet’ like H‐bond. The protected derivative Ac‐β2,2Ac6c‐NHMe ( 4 ) adopts a locally folded gauche conformation about the Cβ? Cα bonds (θ=?55.7°). Of the seven examples of β2,2Ac6c residues reported here, six adopt gauche conformations, a feature which promotes local folding when incorporated into peptides. A comparison between the conformational properties of β2,2Ac6c and β3,3Ac6c residues, in peptides, is presented. Backbone torsional parameters of H‐bonded αβ/βα turns are derived from the structures presented in this study and earlier reports. 相似文献