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     

应用分子图形学、分子力学、量子化学及静电势研究农药分子结构与性能关系（ⅩⅢ））——用比较分子力场方法研究4—肟醚基喹唑啉类化合物的结构与抗瀵草花叶病毒活性的三维构效关系

应用比较分子力场分析（CoMFA)方法研究4－肟醚基喹唑啉类化合物抗烟草花叶病毒活性的三维构效关系（3D－QSAR）,引入分子的摩尔折射率（MR）和偶极矩（DIPOLE）分别作为CoMFA的第三和第四个场。在此基础上进行偏量小二乘（PLS）分析：交叉验证（leave-one-out)结果为rcv^2=0.443,非交叉验证（no valida-tion0结果为r^2=0.932,说明所建立的模型有较好的可靠性,并且在三维等值线图的基础上得到了一个此类化合物的模拟作用模型,据此可生长出一系列先导分子。     

三维球状液晶的模型分子（C6H5）Si（OC6H4）3N结构的PM3研究

三维球状液晶的模型分子（Ｃ６Ｈ５）Ｓｉ（ＯＣ６Ｈ４）３Ｎ结构的ＰＭ３研究＊丁涪江张良辅（中国科学院成都有机化学研究所成都６１００４１）关键词三苯并硅杂烷环状分子ＰＭ３方法液晶分子多为棒状一维结构和盘状二维结构。最近发现三维球状液晶分子，即长链烷烃取代...     

用α—乙酰基硫代甲酰取代胺萃取钯（II）

本文研究了新试剂α－乙酰基硫代甲酰胺对钯（Ⅱ）的萃取性能，用定量构效关系法（ＱＳＡＲ）分析了萃取剂分子中取代基团对萃取分配比Ｄ的影响。     

三明治型金属卟啉、酞菁配合物分子材料

本文论述了３０年代以来三明治型（二层和三层）金属（稀土金属（Ｓｃ，Ｙ，Ｌｎ）、锕系金属（Ｔｈ，Ｐａ，Ｕ，Ｎｐ，Ａｍ）、早期过渡金属（Ｔｉ，Ｚｒ，Ｈｆ）、主族金属（Ｉｎ，Ｓｎ，Ｂｉ））的卟啉、酞菁配合物化学的研究情况，并根据其三维共轭电子结构性质揭示了其作为新型电、磁和光学分子材料的巨大的潜在应用价值和近年来作为分子导体、分子磁体、分子元器件研究方面取得的巨大进展。     

用α-乙酰基硫代甲酰取代胺萃取钯(Ⅱ)

本文研究了新试剂α－乙酰基硫代甲酰胺对钯（Ⅱ）的萃取性能，用定量构效关系法（QSAR）分析了萃取剂分子中取代基团对萃取分配比D的影响。     

柔性羧酸配体一维铜（Ⅱ）配位聚合物的合成与晶体结构

以柔性羧酸配体4-氨基-1,2,4-三氮唑-3,5-二硫代乙酸（H2L）和氯化铜为原料,用常规溶液反应法,制备了配位聚合物[Cu（L）（DMF）（H2O）]n（DMF=N,N-二甲基甲酰胺）,并用X射线衍射分析确定了其晶体结构．结构分析表明：该配合物中每个铜（Ⅱ）为五配位,呈畸变的四方锥构型．与来自两个配体的一个N原子、两个羧基O原子和一个DMF的O原子、一个水分子的O原子配位．配体将Cu（Ⅱ）桥联起来形成沿a轴方向的一维链,链间通过氢键相互连接形成沿b轴方向的二维层,层与层间又通过S…S弱相互作用构筑成三维超分子网络．此外,元素分析、红外光谱和热分析的结果也证实了配合物的组成．     

两亲性四（3－苯基－4－苯甲酰基－5－异噁唑酮）合稀土酸十六烷基吡啶的合成、荧光及成膜性能

合成了４种两亲性的３－苯基－４－苯甲酰基－５－异唑酮（ＨＰＢＩ）合稀土酸十六烷基吡啶配合物：Ｌｎ（ＰＢＩ）４·ＨＤＰ（Ｌｎ＝Ｓｍ，Ｅｕ，Ｔｂ，Ｄｙ）．用元素分析、红外光谱、差热－热重谱、紫外－可见光谱对其进行了表征。研究了这４种配合物在固态下的荧光光谱并用频域法（Ｆｒｅｑｕｅｎｃｙ－ｄｏｍａｉｎ）测定了它们的荧光寿命，另外，还对这４种配合物在空气／水界面上单分子膜的（Ｌａｎｇｍｕｉｒ膜）行为进行了研究，表明它们均能形成稳定的单分子膜。     

钒硫团簇V2S2^＋,V3S4S^＋的结构和稳定性

用ａｂｉｎｉｔｉｏ分子轨道方法（ＲＨＦ,ＵＨＦ）和密度泛函（ＤＦＴ）方法研究了团簇Ｖ２Ｓ２＾＋、Ｖ３Ｓ４＾＋的各种可能的几何构型和电子结构,所得理论能较好地解释有关实验结果。     

含2，4－二硫代乙内酰脲分子片卡宾铁羰基簇合物的合成和结构

Ｆｅ_３（ＣＯ）_（１２）与５个２，４－二硫代乙内酰脲ＳＣＮＨＣ（Ｒ_１）（Ｒ_２）Ｃ（Ｓ）ＮＨ反应制得通式为Ｆｅ_３（ＣＯ）_８（ｕ３－Ｓ）_２（Ｌ）含卡宾配体的５个新铁羰基联合物（１～５），对其进行了元素分析、ＩＲ、~１ＨＮＭＲ和ＭＳ表征，并用Ｘ射线衍射法测定了簇合物３的晶体和分子结构，表明２，４－二硫代乙内酰脲分子片配位基：ＣＮＨＣ（ＣＨ_３）_２Ｃ（Ｓ）ＮＨ的卡宾碳具有ｓｐ~２成键特征，其Ｃ卡宾－Ｆｅ键长０．１８９８ｎｍ，３的分子几何构型维持母体物Ｆｅ_３（ＣＯ）_９（ｕ_３－Ｓ）_２的形状，其中卡宾取代了四方锥分子骨架基底平面Ｆｅ（１）Ｓ（１）Ｆｅ（３）Ｓ（２）的Ｆｅ（１）原子上轴向位置的一个端羰ＣＯ。     

Screening for unknown synthetic steroids in human urine by liquid chromatography-tandem mass spectrometry

Chemically modified steroids (designer steroids), including tetrahydrogestrinone and norbolethone, pose a threat to the integrity of the sport community. These compounds have recently been detected in urine specimens from athletes, resulting in temporary or permanent suspension from amateur and/or professional competition. Triple quadrupole mass spectrometers enable doping control laboratories to screen for unknown, anabolic, androgenic steroids utilizing precursor ion scans. On the basis of common dissociation patterns of steroids with common structural features, characteristic product ions were selected to serve as diagnostic markers for previously unidentified drugs or drug metabolites in human urine samples. An assay was established to complement standard screening procedures. Urine specimens were enzymically hydrolyzed, partitioned into ether, concentrated, and analyzed by precursor ion scanning. Spectra from samples fortified with eight standard compounds (methyltestosterone, ethyltestosterone, 1-testosterone, gestrinone, dihydrogestrinone, tetrahydrogestrinone, norbolethone, and propyltrenbolone) and one deuterium-labeled analog (d(4)-tetrahydrogestrinone) at 50 ng/ml of urine, had precursor ion peaks other than those from common endogenous steroids. Subsequent product ion scan experiments on precursor ions of peaks of unknown origin provided structural identification of the unknown compounds.     

Evaluation of equine urine reactivity towards phase II metabolites of 17‐hydroxy steroids by liquid chromatography/tandem mass spectrometry

Proper storage conditions of biological samples are fundamental to avoid microbiological contamination that can cause chemical modifications of the target analytes. A simple liquid chromatography/tandem mass spectrometry (LC/MS/MS) method through direct injection of diluted samples, without prior extraction, was used to evaluate the stability of phase II metabolites of boldenone and testosterone (glucuronides and sulphates) in intentionally poorly stored equine urine samples. We also considered the stability of some deuterated conjugated steroids generally used as internal standards, such as deuterated testosterone and epitestosterone glucuronides, and deuterated boldenone and testosterone sulphates. The urines were kept for 1 day at room temperature, to mimic poor storage conditions, then spiked with the above steroids and kept at different temperatures (?18°C, 4°C, room temperature). It has been possible to confirm the instability of glucuronide compounds when added to poorly stored equine urine samples. In particular, both 17β‐ and 17α‐glucuronide steroids were exposed to hydrolysis leading to non‐conjugated steroids. Only 17β‐hydroxy steroids were exposed to oxidation to their keto derivatives whereas the 17α‐hydroxy steroids were highly stable. The sulphate compounds were completely stable. The deuterated compounds underwent the same behaviour as the unlabelled compounds. The transformations were observed in urine samples kept at room temperature and at a temperature of 4°C (at a slower rate). No modifications were observed in frozen urine samples. In the light of the latter results, the immediate freezing at ?18°C of the collected samples and their instant analysis after thawing is the proposed procedure for preventing the transformations that occur in urine, usually due to microbiological contamination. Copyright © 2008 John Wiley & Sons, Ltd.     

Improvement and extension of the application scope for matrix-assisted laser desorption/ionization mass spectrometric analysis-oriented N-alkylpyridinium isotope quaternization

Based on our previous report on N-alkylpyridinium isotope quaternization (NAPIQ) for the analysis of cholesterol and fatty alcohols, we have further developed the NAPIQ method for wider applications in screening various small compounds. The reaction scope and improvement were investigated via the screening of compounds with different reaction sites. The experimental results showed that the NAPIQ strategy was suitable not only for steroids with alcoholic or α,β-unsaturated ketone moieties, but could also be applied to label carbohydrates by changing the reaction solvent. The byproducts from target compounds with multiple groups could be reduced by improving the reaction conditions. The derivatization method significantly improved the detection sensitivity for these compounds in matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric (MALDI-FTMS) analysis. The detection sensitivity and selectivity of the NAPIQ method were higher than conventionally used Girard reagents. Finally, endogenous steroids in urine samples were screened using the NAPIQ method. NAPIQ was proven to be an efficient alternative method for analyzing steroids and carbohydrates, without the need for isotopically coded internal standards.     

Structural basis for the discrepancy of spectral behavior in C-H stretching band between steroids and long chain hydrocarbon compounds

The discrepancies of the spectral behavior for the C-H stretching band between some long chain hydrocarbon compounds and steroids were investigated. At low temperature, the C-H stretching bands exhibit complex fine structure in steroids but remain simple in long chain hydrocarbon compounds. MM3 molecular mechanics calculation indicates that, for long chain hydrocarbon compounds, the C-H groups vibrate with large scale coupling. There exist a few bands where the C-H groups vibrate in synchronous and inphase mode. Thus the variations of dipole moment for these bands are enhanced and the intensities are obviously stronger than others and cover other band in the spectra. This is just the reason why the C-H stretching bands are simple even at low temperature environment. Nevertheless, for the steroids, the C-H stretching bands vibrate with local coupling mode. The synchronous enhancement effect does not occur, the differences of intensities for various modes are not as large as those in long chain hydrocarbo     

Heterocyclic steroids: Synthetic routes and biological characteristics of steroidal fused bicyclic pyrimidines

Natural steroids are characterized as a vital class of compounds, a type of secondary metabolites and components of cell membranes that widely accessible in plants or animals displayed significant pharmacological and varied biological properties. The present study aims to highlight the conveyed researches of synthetic routes adopted to obtain the various structures of steroidal fused bicyclic pyrimidines with substantial biological and pharmaceutical importance. The topic was discussed in light of the synthesis of fused [6 + 5] bicyclic systems, fused [6 + 6] bicyclic systems, binary heterocycles, and biological applications. In detail, the various synthetic strategies for the construction of steroids fused to bicyclic pyrazolopyrimidines, thiazolopyrimidines, triazolopyrimidines, pyridopyrimidines, pyranopyrimidines, and binary pyrimidines were discussed. Heterocyclic steroids of this class of compounds demonstrated potent anticancer, anti-proliferative, anti-neuro-inflammatory, anti-inflammatory, and anti-ulcer activities. It was perceived that the synthetic steroids of such bicyclic pyrimidine scaffolds are fused into the steroid basic skeleton is essential for the potent bioactivities.     

Steroid and steroid glucuronide profiles in urine during pregnancy determined by liquid chromatography–electrospray ionization-tandem mass spectrometry

An ultra performance liquid chromatography–electrospray ionization-tandem mass spectrometry (UPLC–MS/MS) method was developed for the analysis of steroids and their glucuronides in urine samples. The method provides high sensitivity and fast analysis, as both steroids and their glucuronides can be analyzed directly without hydrolysis or complex sample preparation. The method was applied in profiling of targeted and nontargeted steroids and steroid glucuronides during pregnancy. The concentrations of 11 of 27 targeted steroids and steroid glucuronides and the concentrations of 25 nontargeted steroid glucuronides increased about 10–400 fold during the pregnancy. The concentrations of most of these 36 compounds began to increase in the first days of the pregnancy, increased gradually during the pregnancy, achieved a maximum in late pregnancy, and decreased sharply after delivery. Exceptionally, the concentrations of allopregnanolone and 17-hydroxypregnenolone started to increase later than those of the other steroids. Moreover, the concentrations of E2 glucuronides began to decrease one week before the delivery, in contrast to most of the steroids and steroid glucuronides, whose concentrations dropped sharply during the delivery. Concentrations of 34 compounds decreased noticeably when the subject was on sick leave owing a series of painful contractions. The results suggest that steroids and especially steroid glucuronides may provide a valuable diagnostic tool to follow the course of pregnancy.     

Liquid chromatographic and spectral analysis of the 17-hydroxy anabolic steroids

The liquid chromatographic properties of various 17-hydroxy anabolic steroids are examined under reversed-phase conditions. These anabolic steroids are now listed as controlled drugs in many states due to their abuse potential in athletics, body building, and other areas. These nonesterified steroids are separated on a C18 stationary phase with a 70% methanol in water mobile phase. In a few cases, two compounds display very similar retention properties. However, dual-wavelength detection at 254 and 280 nm allows for their differentiation. Reversed-phase retention parallels steroid lipophilicity based on hydroxyl and methyl group substituents. Also, those steroids containing a dienone substructure are more polar than steroids containing an enone moiety.     

Structural Modification for Antitumor Nitrogenous Steroids

Natural steroids have been showing notable cytotoxic activities, which are quite interesting lead compounds for the development of anticancer drug including estramustine and prednimustine. Considering that these semi-synthetic molecules are nitrogen mustard functionalized steroidal derivatives, the present review is focused on the methodologies of introducing nitrogen atom or nitrogen-containing heterocycles on A~D rings or side chains of steroids, and analysis of the structure-activity relationship(SAR) for these man-made cytotoxic steroids.