Agostic bonds in cyclometalation

Cyclometalation reactions proceed very easily with one step reaction between metal compounds and substrates having a heteroatom such as O, S, N, P and As. However, under mild reaction conditions, many agostic compounds which are intermediates in these cyclometalation reactions, can be isolated. The metal compounds used for the formation of these agostic intermediates are both transition metal and main group metal compounds. The substrates are nitrogen-containing compounds, phosphorus-containing compounds, oxygen-containing compounds and sulfur-containing compounds. These agostic intermediates are mainly δ-C-H agostic compounds, some are γ-C-H agostic compounds and very few are ?-C-H-agostic compounds. The agostic intermediates are prepared, usually, under mild reaction conditions in the cyclometalation reaction. These agostic compounds are also prepared from cyclometalation reaction products, e.g., by the protonation, irradiation, and elimination of ligand molecules by vacuum, inert gas current, dehydration with a molecular sieves 4A, etc. Some agostic compounds are utilized for preparation of stable catalysts, e.g., hydrogenation catalysts.     

白石湖煤液化粗油加氢精制过程硫、氮化合物转化规律

采用实沸点蒸馏仪对白石湖煤液化油进行馏分切割,切取<170℃液化粗油进行加氢精制脱除其中硫、氮化合物,采用硫化学发光气相色谱仪（GC-SCD）、氮化学发光气相色谱仪（GC-NCD）对液化粗油和精制油中硫、氮化合物进行分析表征,研究加氢精制过程硫、氮化合物的转化规律。结果表明,液化粗油中含硫化合物主要是噻吩类化合物和硫醇,经过加氢精制后基本消失,苯并噻酚类化合物脱除比例要低于噻吩类化合物,属于较难脱除含硫化合物。液化粗油中含氮化合物主要是苯胺类化合物,其次是吲哚类化合物,经过加氢精制吲哚类化合物全被脱除,苯胺和喹啉类化合物属于碱性含氮化合物,是精制油中残留的主要含氮化合物,含量达1.61 mg/kg。     

Prediction of the molar volume at the normal boiling point

A group contribution method for the prediction of the molar volume at the normal boiling point has been developed. The method can be used for organic and inorganic compounds. It cannot be used for elements and diatomic molecules. Group contributions are shown for a wide variety of hydrocarbons, organic halogen compounds, organic oxygen compounds, organic nitrogen compounds, organic sulfur compounds, organic boron compounds, organic silicon compounds, miscellaneous organics, and many inorganic compounds.Contrary to the corresponding states methods for the prediction of molar volumes, knowledge of critical properties, acentric factors, and reference volumes is not needed.     

某些结构受阻氧鎓盐的吸收和荧光

氧锅盐是一类带正电行的杂环化合物，作为一种合成中间体，氧锅盐在有机合成方面已得到广泛的应用［’］近年来人们对其发光和光谱性质的研究也给予足够的注意．这是由于很多氧锅盐化合物有着很强的荧光发射【’J，并且其中有些已被用作激光染料出或Q一开关材料卜1由于氧钠盐强烈的亲电特性，因而它在聚乙烯咋哇电照相体系中也受到特殊的注意，即通过它来捕获电子和诱导分子内正空穴向负电极方向迁移问染料分子的刚性化对激发分子的弛豫过程往往会带来巨大的影响，如非刚性化分子会通过分子内自由旋转使分子在激发态的弛豫过程中形成不同的…     

某些结构受阻氧鎓盐的吸收和荧光

A series of pyrylium compounds with different structures have been synthesized. The photophysical behavior of these compounds has also been measured. Results show that the structures of compounds and the polarities of solvents make great effects on the photophysical behaviors of compounds, especially when the structures of compounds are hindered. It indicats that the intramolecular rotation relaxation of compounds in excited state in closely related to the fluorescence quantum yields of compounds.     

Lead validation and SAR development via chemical similarity searching; application to compounds targeting the pY+3 site of the SH2 domain of p56lck

Compound selection based on chemical similarity has been used to validate active "parent" compounds identified via database searching as viable lead compounds and to obtain initial structure-activity relationships for those leads. Twelve parent compounds that have inhibitory activity against the SH2 domain of the p56 T-cell tyrosine kinase (Lck) are the focus of this study. Lck is involved in the T-cell mediated immune response, and inhibitors of Lck protein-protein interactions could potentially be used to develop novel immunosuppressants. Similarity searches for each parent compound were performed using 2D structural fingerprints on a database containing 1,300,000 commercially available compounds. The inhibitory activity of the selected compounds was assessed using enzyme immunoassay (EIA). In general, the most active parent compounds yield the most high activity similar compounds; however, in two cases low activity parent compounds (i.e. inhibitory activity < 25% at 100 microM) yielded multiple similar compounds with activities > 60%. Such compounds may, therefore, be considered as viable lead compounds for optimization. Structure-activity relationships were explored by examining both ligand structures and their computed bound conformations to the protein. Functional groups common to the active compounds as well as key amino acid residues that form hydrogen bonds with the active compounds were identified. This information will act as the basis for the rational optimization of the lead compounds.     

含氧、氮、硫杂螺环结构的光致变色化合物研究进展

有机螺环光致变色化合物具有较好的化学稳定性、光敏性和抗光疲劳性, 可应用于光过滤器及光学记录存储. 为了获得性能优良的螺环光致变色化合物, 新的设计合成一直是该领域研究的热点. 总结了对含氧、氮、硫杂螺环结构的光致变色化合物的研究进展, 描述了螺环化合物的结构特征和部分化合物的合成过程, 展望了螺环光致变色化合物的发展前景.     

The identification of new ATAD2 bromodomain inhibitors: the application of combined ligand and structure-based virtual screening

Ligand-based virtual screening (LBVS) and structure-based virtual screening (SBVS) approaches were used to identify new inhibitors for ATAD2 bromodomain. The LBVS approach was used to search 23,129,083 clean compounds to identify compounds similar to an active compound with reported pIC₅₀ equal to 7.2. Based on LBVS results, 19 compounds were selected. To perform SBVS, by applying nine filters on 23,129,083 clean compounds, 1,057,060 compounds were selected. After performing SBVS on these selected compounds with idock software, 16 compounds with the lowest binding energies were selected. More accurate molecular docking analysis was performed on these 35 selected compounds by using iGEMDOCK software and six of them with the lowest binding energies were selected as hit compounds. These compounds were zinc36647229, zinc77969074, zinc13637358, zinc77971540, zinc12991296 and zinc19374204.     

Synthesis, Chemistry, and Applications of Heterocyclic Cage Compounds (V)

The synthesis and chemistry of polycyclic of cage compounds have attracted considerable attention in recent years. The vast majority of the work reported in this area has dealt with carbocylic cage compounds. On the other hand, the synthesis and chemistry of heterocyclic cage compounds have received less attention. Recently, we envisioned that studies on the synthesis and chemistry of heterocyclic cage compounds can greatly expand the scopes and utilities of cage compounds.1 As part of a program that involves the synthesis, chemistry, and application of heterocyclic cage compounds, we report here the synthesis of new thia-oxa-cage compounds and the chemical nature of these thia-cages.     

多功能光致变色化合物

有机光致变色化合物是一种新型有机功能化合物,可广泛应用于光存储、光开关和光转换器件等领域,本文综述近几年来双光致变色化合物体系及具有荧光性能、磁性能等多功能光致变色化合物体系的研究进展,并对有机光致变色化合物的研究应用做了展望。     

三脚架结构化合物及其配合物研究进展

本文按三脚架结构化合物中心部分构成的不同。分四类对配体及其配合物的结构,性能进行了介绍。（1）以环为中心的三脚架结构化合物;（2）以氮原子为中心的三脚架结构化合物;（3）以碳原子为中心的三脚架结构化合物;（4）以硼原子及磷原子为中心的三脚架结构化合物。     

Data shaving: a focused screening approach

The number of compounds available for evaluation as part of the drug discovery process continues to increase. These compounds may exist physically or be stored electronically allowing screening by either actual or virtual means. This growing number of compounds has generated an increasing need for effective strategies to direct screening efforts. Initial efforts toward this goal led to the development of methods to select diverse sets of compounds for screening, methods to cluster actives into related groups of compounds, and tools to select compounds similar to actives of interest for further screening. In this work we extend these earlier efforts to exploit information about inactive compounds to help make rational decisions about which sets of compounds to include as part of a continuing screening campaign, or as part of a focused follow-up effort. This method uses the information from inactive compounds to "shave" off or deprioritize compounds similar to inactives from further consideration. This methodology can be used in two ways: first, to provide a rational means of deciding when sufficient compounds containing certain structural features have been tested and second as a tool to enhance similarity searching around known actives. Similarity searching is improved by deprioritizing compounds predicted to be inactive, due to the presence of structural features associated with inactivity.     

Synthesis,Chemistry and Applications of Heterocyclic Cage Compounds (V)

The synthesis and chemistry of polycyclic cage compounds have attracted considerable attention in recent years.¹ The vast majority of the work reported in this area has dealt with caybocyclic cage compounds. On the other hand, the synthesis and chemistry of heterocyclic cage compounds have received less attention. Recently, we have accomplished the synthesis of a series of oxa-cage compounds and performed the chemical transformations of these oxa-cage compounds.² As part of a program that involves the synthesis,chemistry and applications of heterocyclic cage compounds we report here the synthesis of heterocyclic cage compounds 1-12. We also wish to report the applications of compounds 7-12 on the π-facial selectivities. Studies on the cation-binding properties of compounds 1 and 2 and other oxa-cages are undertaken.     

Dinitroso and polynitroso compounds

The growing interest in the chemistry of C-nitroso compounds (RN=O; R = alkyl or aryl group) is due in part to the recognition of their participation in various metabolic processes of nitrogen-containing compounds. C-Nitroso compounds have a rich organic chemistry in their own right, displaying interesting intra- and intermolecular dimerization processes and addition reactions with unsaturated compounds. In addition, they have a fascinating coordination chemistry. While most of the attention has been directed towards C-nitroso compounds containing a single -NO moiety, there is an emerging area of research dealing with dinitroso and polynitroso compounds. In this critical review, we present and discuss the synthetic routes and properties of these relatively unexplored dinitroso and polynitroso compounds, and suggest areas of further development involving these compounds. (126 references.).     

A mass spectrometric investigation of non-covalent interactions between ruthenium complexes and DNA

Electrospray ionisation mass spectrometry was used to investigate reactions between six ruthenium compounds and three different non self-complementary duplex oligonucleotides containing 16 base pairs. Each of the compounds studied formed non-covalent complexes containing between one and five ruthenium molecules bound to DNA. Competition experiments involving duplex 16mers and pairs of ruthenium compounds were used to determine the order of relative binding affinities of the metal compounds. Other competition experiments involving ruthenium compounds, and the organic DNA binding agents daunomycin and distamycin, provided information about the sites and modes of DNA binding of the ruthenium compounds.     

Adsorbed compounds on pine needle surfaces for the environmental monitoring of uranium

In order to examine the feasibility of the adsorbed compounds on the pine needles for environmental monitoring of uranium, the adsorbed compounds were recovered by solvent washing, and the elemental concentrations in the compounds were compared with those of air particles and pine needles. It was found, that the concentration patterns of elements in the compounds corresponded to those of air particles, which meant that the air particles were the main components of the compounds. The analysis by ICP-MS suggested that the uranium in the compounds has a natural composition. Therefore, the adsorbed compounds to the pine needles can be considered as potential indicators for the environmental monitoring of uranium.     

顶空固相微萃取-气相色谱-质谱法测定小米黄酒风味成分

为全面了解小米黄酒风味成分的构成和气味特征,优化了85μm聚丙烯酸酯(PA)、100μm聚二甲基硅氧烷(PDMS)、75μm碳分子筛(CAR)/PDMS、50/30μm二乙烯基苯(DVB)/CAR/PDMS萃取头提取小米黄酒风味成分的条件,采用顶空固相微萃取(headspace solid phase microextraction,HS-SPME)-气相色谱-质谱法(GC-MS)对风味成分进行定性、定量分析,并计算气味活性值(odor active value,OAV),同时利用OAV分析风味成分的气味特征和气味强度。结果显示:不同萃取头的最优萃取条件为样品量8 mL、萃取时间40 min、萃取温度60℃、NaCl添加量1.5 g。小米黄酒风味成分由醇、酯、含苯化合物、烃、酸、醛、酮、烯、酚和杂环类化合物构成,醇为主要风味成分。通过OAV确定了苯乙醇、苯乙烯、2-甲基萘、1-甲基萘、苯甲醛、苯乙醛、2-甲氧基-苯酚为小米黄酒气味特征成分,苯基乙醇、苯乙醛对气味贡献最大。PA和PDMS萃取头分别对极性和非极性化合物具有较好的吸附效果,CAR/PDMS和DVB/CAR/PDMS萃取头对中等极性化合物具有较好的吸附效果。该研究全面了解了小米黄酒风味成分的构成,为其产品开发及品质控制提供理论了依据。     

Recent developments in the non-cyclopentadienyl organometallic and related chemistry of scandium

Up to the early to mid 1990s the organometallic chemistry of scandium was dominated by cyclopentadienyl derivatives. This present article highlights advances in the synthesis and reactivity of non-cyclopentadienyl organometallic and related compounds of scandium. These include: compounds containing arene and other eta(x)-CxRx ligands; compounds with macrocyclic and fac-L3 ligands; compounds with polydentate ligands that incorporate amide donors; compounds with bidentate, monoanionic N,N' donor ligands; and compounds with iminophenolate, bis(phenoxide) and some other anionic O-donor ligands.     

Stacking-Conformations in Functionally Substituted Phosphines

The methods of synthesis and space structure of phosphorus-containing compounds, in which stacking conformation is realized, are considered. It is shown that intramolecular stacking can be observed in monoheterocyclic compounds, bi-and polycyclic compounds, complexes of metals and acyclic compounds.