NAMI-A型钌配合物(HL)[trans-RuCl4L(dmso-S)] (L=1-methyl-1,2,4-triazole)水解机理的理论研究

用量子化学密度泛函方法结合导体极化连续模型研究了具有潜在抗肿瘤活性的NAMI-A型钌配合物(HL)[trans-RuCl₄L(dmso-S)](L=1-methyl-1,2,4-triazole,dmso-S=S-dimethyl sulfoxide) (1)的水解反应过程．计算得到该配合物水解反应过程中相应的结构特征和详细的反应势能面．对于第一步水解,液相中配合物1的活化能垒比已经报道的抗肿瘤药物(Him)[trans-RuCl₄(     

Hydrolysis Mechanism of the NAMI-A-type Antitumor Complex (HL)[trans-RuCl4L(dmso-S)] (L=1-methyl-1,2,4-triazole)

The hydrolysis process of Ru(III) complex (HL)[trans-RuCl₄L(dmso-S)] (L=1-methyl-1,2,4-triazole and dmso-S=S-dimethyl sulfoxide) (1), a potential antitumor complex similar to the well-known antitumor agent (Him)[trans-RuCl₄L(dmso-S)(im)] (NAMI-A, im=imidazole), was investigated using density functional theory combined with the conductor-like polarizable continuum model approach. The structural characteristics and the detailed energy profiles for the hydrolysis processes of this complex were obtained. For the first hydrolysis step, complex 1 has slightly higher barrier energies than the reported anticancer drug NAMI-A, and the result is in accordance with the experimental evidence indicating larger half-life for complex 1. For the second hydrolysis step, the formation of cis-diaqua species is thermodynamic preferred to that of trans isomers. In addition, on the basis of the analysis of electronic characteristics of species in the hydrolysis process, the trend in nucleophilic attack abilities of hydrolysis products by pertinent biomolecules is revealed and predicted.     

2种吲哚衍生物的N-烷基化产物的制备

吲哚-3-乙醛酸甲酯和3-吲哚乙腈在碱存在下,以烷基卤或硫酸烷基酯为亲电试剂进行N-烷基化反应,合成了6种新的N-烷基化吲哚化合物。 研究了吲哚化合物及烷基化试剂的结构、溶剂和碱对N-烷基化反应的影响。 具有强吸电子取代基的吲哚-3-乙醛酸甲酯使用弱碱Cs2CO3在室温就可顺利进行烷基化反应,产率达到93%;而具有较弱吸电子取代基的3-吲哚乙腈,需要使用强碱NaH才能进行烷基化反应。     

国际医学物理学的新发展

文章评述了国际医学物理学近印年的新发展，着重介绍了数字影像物理学和放射治疗物理学的新进展及其对临床应用高新医疗器械的重要作用，并谈及国际医学物理学的新发展对中国医学物理学发展的启示．     

新型双吲哚马来酰亚胺衍生物的合成

以1-(3-氧代四氢吡喃丙基)-吲哚-3-乙醛酸甲酯(5)和吲哚-3-乙酰胺(6)为原料,在催化剂叔丁醇钾的四氢呋喃溶液存在下发生偶合反应,经浓盐酸处理得脱保护的中间体7,再经甲磺酰化反应、氨解反应得到4种新的具有不同氨烷基侧链的双吲哚马来酰亚胺衍生物9a,9b,9d,9e.目标产物结构通过1H NMR,13C NMR,MS和HRMS确证.     

Precursor‐involved and Conversion Rate‐controlled Self‐assembly of a 'Super Gelator' in Thixotropic Hydrogels for Drug Delivery

Enzymatic hydrogelation is a totally different process to the heating‐cooling gelation process, in which the precursors of the gelators can be involved during the formation of self‐assembled structures. Using thixotropic hydrogels formed by a super gelator as our studied system, we demonstrated that the enzyme concentration/conversion rate of enzymatic reaction had a strong influence on the morphology of resulting self‐assembled nanostructures and the property of resulting hydrogels. The principle demonstrated in this study not only helps to understand and elucidate the phenomenon of self‐assembly triggered by enzymes in biological systems, but also offers a unique methodology to control the morphology of self‐assembled structures for specific applications such as controlled drug release.     

Synthesis,Crystal Structure and Biological Activity of N-(2-hydroxy-3-(4-(2-methoxyphenyl)-piperazin-1-yl)propyl)quinoxaline-2-methanamide

The title compound N-(2-hydroxy-3-(4-(2-methoxyphenyl)piperazin-1-yl)propyl)-quinoxaline-2-methanamide(4, C23H27N5O3, Mr = 421.50) was synthesized via a four-step reaction and characterized by 1H NMR, 13 C NMR, ESIMS and single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 12.108(2), b = 12.639(3), c = 14.601(3) , β = 104.87(3)o, V = 2159.6(8) 3, Z = 4, Dc = 1.296 g/cm3, S = 1.023, μ = 0.088 mm-1, F(000) = 896, R = 0.0392 and w R = 0.0983 for 2836 observed reflections with I 2σ(I). The single-crystal X-ray structural analysis reveals that 4 is stabilized by intramolecular and intermolecular hydrogen bonds together with π-π interactions. The bioassay showed that 4 exhibited high selective activity for α1A/D vs. α1B-adrenoceptors subtype.     

Asymmetric synthesis of vicinal amino alcohols via organocatalytic sequential α-amination/Grignard addition reactions of aldehydes

An organocatalytic sequential α-amination/Grignard addition reaction of aliphatic aldehydes is reported. The synthetically useful anti-vicinal amino alcohol derivatives were obtained in high yields and with high stereoselectivities. These derivatives could be easily transformed into oxazolidinones.     

A novel beta-mannanase with high specific activity from Bacillus circulans CGMCC1554: gene cloning, expression and enzymatic characterization

A DNA fragment of 2,042 bp containing a novel β-mannanase gene, man5A, was identified from the genome of the mannan-degrading bacterium Bacillus circulans CGMCC1554. The open reading frame of man5A comprised 978 bp encoding a protein of 326 amino acids with a predicted molecular weight of 32 kDa. The amino acid sequence of the encoded mannanase, MAN5A, showed the highest identity (78.5%) to β-mannanases belonging to glycosyl hydrolases family 5. The gene man5A was efficiently expressed in Escherichia coli and Pichia pastoris with the highest activity of 541 U/ml in a 3-L fermenter. Recombinant MAN5A purified from E. coli had a high specific activity of 4,839 U/mg, which is much higher than that of enzymes that showed high sequence identity. The enzyme showed maximum activity at pH 7.6 and 60 °C and resistance to trypsin. After hydrolysis of LBG, oligomannosides accounted for 76% of the hydrolysis products. All these properties collectively make MAN5A a better candidate than current mannanases for use in the food and feed industry.