醇类化合物热值改进剂的定量结构-色谱保留相关性研究

计算表征了醇类化合物热值改进剂的部分分子连接性指数和5个量子化学参数,同时运用多元线性回归方法对参数进行了优化筛选,在2种不同极性强弱的固定相(PH-5、RTX-WAX)上,分别建立了9种和11种醇类化合物热值改进剂的气相色谱保留值(t)与分子连接性指数和量子化学参数的定量结构-色谱保留关系(QSRR)模型。其相关系数分别为R=0.997和R22=0.971,关系式可分别表示为模型1:t1=-5.972-0.047 ET-1.857~3X_p~v和模型2:t_2=-2.409-0.034 ET,在2种固定相上的QSRR模型的建模计算值复相关系数(R)、采用留一法(leave-one-out)交互检验复相关系数(R)分别为:R_1=0.998、R_(1CV)=0.999和R_2=0.985、R_(2CV)=0.999,结果表明:模型1和模型2与色谱保留指数显著相关的分别有总能量ET、三阶分子连接性指数~3X_p~v和总能量ET,所建模型具有良好稳定性和预测能力,分子连接性指数和量子化学参数能较好地反映化合物的结构特征。     

醇类化合物气相色谱保留指数的分子拓扑研究

分子中原子i的特征值(ti)定义为tj＝1 ∑hi。并计算了醇类化合物的氢连接性指数，藉助多元线性回归技术分别建立了25个醇类化合物的指数与这些物质的气相色谱保留指数的定量结构／性质相关关系模型。模型具有良好的稳定性和预测能力，氢连接性指数能较好地反映化合物的结构特征。     

烟碱型乙酰胆碱受体吡啶基胺类配体的构效关系研究

采用分子动力学模拟退火技术寻找了一类新型烟碱型乙酰胆碱受体吡啶基胺类配体分子的优势构象，用分子力学方法进行了结构优化，再用半经验量子化学方法中的AM1方法进一步优化，并做了电子结构计算.用计算所得物化参数对配体亲和性进行多元线性回归分析，回归结果表明：化合物pKi值与分子最低空轨道能量(ELUMO)、吡啶基所带总电荷(Qp)及分子构象相关.根据计算结果对该类化合物与受体的作用机制和作用位点进行了讨论.     

致癌有机化合物分子片段致癌机理的研究

以有机物的分子连接性指数和微扰分子轨道指数作结构、能量参数,从分析致癌有机物分子片段与生物遗传基因DNA链互补碱基对发生共价交联的构效角度出发,首次得出产生碱基移码型或碱基置换型化学致癌的主要过程是化合物分子片段中活性原子与DNA互补碱基对间氢键的共价结合,显示致癌活性的充分必要条件是碱基对G≡C间有两个氢键与致癌分子片段发生特异交联.对100余种已知致癌物的致癌分子片段进行计算分析,成功地获得了有机物分子片段定量结构-致癌活性的估测模式.     

基于DFT和分子连接性指数方法研究醇类化合物的水溶解度和分配系数

将DFT方法计算得到的量化参数和分子连接性指数联合应用到60个醇类化合物的溶解度和辛醇/水分配系数的QSPR研究中,分别通过逐步回归得到具有显著统计意义的4个参数和5个参数的QSPR方程.以此4个参数和5个参数分别作为输入参数,采用BPNN,RBFNN方法建立了QSPR预测模型,使用Latin-partition交叉验证方法评价模型的预测能力.BPNN,RBFNN模型对溶解度预测的相关系数分别为0.993和0.994,而对辛醇/水分配系数预测的相关系数分别0.990和0.997,结果令人满意.     

硝基芳烃对鲤鱼肝脏过氧化氢酶的抑制及构效关系研究

在离体实验条件下，测定了１４种硝基芳烃化合物对鲤鱼肝脏过氧化氢酶的半抑制浓度ＥＣ５０值，根据－ｌｇＥＣ５０值，以一阶价分子连接性指数＾１Ｘ＾ｖ、取代基数总和Σσ＾－、指示变量Ｉ、分子分支指数＾１Ｋα、分子最低空轨道能ＥＬＵＭＯ及辛醇－水分配系数ｌｇＰ为参数，进行定量结构活性相关性研究。     

鲤鱼组织ATPase活性抑制和构效分析

在离体实验条件下测定了20种硝基芳烃化合物对鲤鱼鳃和肾的ATPase活性的半抑制浓度c_I50值.以辛醇-水分配系数1gp、一阶价分子连接性指数¹x^v、指示变量I、分子分支指数¹K_a、取代基常数总和∑_σ-和分子最低空轨道能E_lumo为参数,依据20种硝基芳烃化合物对鲤鱼鳃和肾的ATPase活性的半抑制浓度-lgc_I50值,进行构效分析,建立了20种硝基芳烃化合物的QSAR方程.结果表明,∑_σ-、I、E_lumo3个参数与硝基芳烃对鲤鱼组织ATPase毒性密切相关,并预测和探讨了毒性作用机制.     

7,10-位取代喜树碱衍生物的QSAR研究

利用密度泛函理论(DFT)在杂化泛函B3LYP和基组6-311G(d,p)水平下对7,10-位双取代喜树碱衍生物(CPTs)进行了构型优化,计算出分子的电子结构描述符,利用Chemoffice 8.0软件计算出几个相关的物化描述符;采用逐步多元回归法对该组化合物的抗癌活性与分子描述符之间建立了定量结构-活性关系(QSAR)模型。所建最佳三参数QSAR模型的复相关系数R=0.951;用留一法(leave-one-out,LOO)进行交互检验,得到交互检验系数RCV2=0.778。结果表明,所得QSAR模型具有良好的预测能力,而且影响药物活性的主要因素有化合物分子的结构、最高占据和最低空分子轨道能量差及13-位碳原子的净电荷。     

定域分子轨道模型——含H、C、N、O有机小分子的研究

应用STO_(-3)G从头算方法和Fostre-Boys定域化分子轨道程序, 我们研究了20多个有机小分子(含H、C、N,O)的定域化分子轨道, 获得了它们的能量和相互作用参数。采用定域分子轨道模型和统一的参数, 对正醇类分子进行了计算, 与光电子能谱数据比较, 得到的电离能的计算结果是相当令人满意的。     

分子连接性指数与溶液吸附自由能的相关性

测定了硅胶自四氯化碳中吸附脂肪醇及活性炭自水中吸附芳香化合物的吸附等温线, 等温线均可用Langmuir方程描述。利用Langmuir参数计算了各体系的吸附标准自由能变化。计算了各种吸附质的分子连接性指数。各种分子的分子连接性指数与吸附标准自由能变化间有相关性, 并给出了相关方程, 同时作了初步的讨论。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.