Diastereoselective protonation of lactam enolates derived from (R)-phenylglycinol. A novel asymmetric route to 4-phenyl-1,2,3, 4-tetrahydroisoquinolines

Highly diastereoselective protonation of chiral lactam enolates of 4-substituted-1,4-dihydroisoquinolin-3-ones is reported. Protonation and alkylation processes of these lactam enolates derived from phenylglycinol occur with opposite diastereofacial selectivity. This diastereoselective protonation has been applied to the asymmetric synthesis of (4S)-N-methyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline 9 obtained in up to 97% ee.     

Synthesis of a Novel Type of Phosphates of Puerarin

A novel type of phosphated puerarin derivatives were synthesized through a simplified Atheron‐Todd reaction for the first time. The structure of these compounds were elucidated by IR, ESI‐MS and NMR. Moreover, the reason the dialkylphophite reagent had different chemselectivities toward different hydroxys on the puerarin was discussed.     

High-performance liquid chromatography of some basic drugs on a n-octadecylphosphonic acid modified magnesia-zirconia stationary phase

The high-performance liquid chromatographic behavior of some basic drugs was studied on a n-octadecylphosphonic acid modified magnesia-zirconia (C18PZM) stationary phase. The effect of mobile phase variables such as methanol content, ionic strength, and pH on their chromatographic behavior was investigated. The retention mechanism of basic drugs on the stationary phase was elucidated. The results indicate that both hydrophobic and cation-exchange interactions contribute to solute retention under most chromatographic conditions. The inherent Br?nsted-acid sites and also the adsorbed Lewis base anionic buffer constituents on accessible ZM surface Lewis acid sites play a role in the retention of ionized solutes by cation-exchange interaction. However, especially at high mobile phase pH, the retention of basic drugs depends mainly on hydrophobic interactions between solutes and support. Separations of the basic drugs on the C18PZM phase by a predominantly reversed-phase retention mode were very promising. The mixed-mode retention feature on this phase, as a result of the adsorbed Lewis base anionic buffer constituents acting as sites for cation-exchange, could also be very useful, e.g. for enhancing the chromatographic selectivity of such analytes. The C18PZM seems to be an excellent alternative to silica-based reversed-phase stationary phase for the separation of strongly basic solutes.     

Assignment of acetyl groups to O-2 and/or O-3 of pectic oligogalacturonides using negative electrospray ionization ion trap mass spectrometry

Partially acetylated and methylated oligogalacturonides produced by enzymatic hydrolysis of sugar beet pectin were analysed by negative electrospray ionization ion trap mass spectrometry (ESI-ITMS). The (18)O labelling of the oligomer reducing end allowed the precise assignment of the fragments resulting from glycosidic bond and cross-ring cleavages. The collisional-induced dissociation of the C(i) and Z(j) fragment ions through sequential MS(n) experiments always displayed (0, 2)A-type cross-ring cleavage ions which were related to C(2)H(4)O(2) losses. These (0, 2)A ions appeared to be highly diagnostic ions allowing the precise location of the acetyl groups to the O-2 and/or O-3 of the acetylated galacturonic acid residues.     

Intramolecular Alkyne Coupling in the Reaction of 1,8-bis(phenylethynyl)naphthalene with Pt2Ru4(CO)18

The reaction of Pt₂Ru₄(CO)₁₈, 1 with 1,8-bis(phenylethynyl)naphthalene, 2 has yielded two metal carbonyl cluster complexes: Ru₂(CO)₆[- ²-C₁₀H₆C₄Ph₂], 3 (60% yield) and Ru₂Pt(CO)₆[- ²-C₁₀H₆C₄Ph₂]₂, 4 (8% yield). Both compounds were characterized by a single crystal X-ray diffraction analysis. Both products were formed as a result of fragmentation of the Pt₂Ru₄ cluster of 1. Compound 3 contains two ruthenium atoms. They are bridged by a tricyclic C₁₀H₆C₄Ph₂ ligand formed by the coupling of the two -carbon atoms of the alkyne groups. The -carbon atoms of the alkynes are -bonded to one of the ruthenium atoms to form a metallacycle and this entire group is -bonded to the second ruthenium atom. Compound 4 contains two ruthenium atoms with a platinum atom between them. This molecule contains two tricyclic C₁₀H₆C₄Ph₂ ligands similar to that in 3, and two metallacycles formed by coordination of the -carbon atoms of both ligands to the platinum atom. One ligand is -bonded to each of the ruthenium atoms.     

催化材料对病毒的吸附和灭活作用及对哺乳动物细胞的毒性

 提出了以吸附和催化原理灭活病毒的设想，旨在开发出对病毒有过滤、吸附及灭活作用的高效非特异性催化材料，应用于各种防护设施，有效控制非典型肺炎（SARS）的传播．采用与SARS病毒相似的副流感病毒作为模拟对象，进行了吸附及灭活该病毒的催化材料研究，并考察了催化材料对哺乳动物细胞的毒性．结果表明，病毒气溶胶的阻留及吸附结果与基于DNA吸附的色谱分析结果相一致；部分材料可以强烈地吸附病毒（100％），甚至在强烈振荡下并洗脱至第3次，病毒也不能脱附；一些材料不仅可以吸附病毒，而且强烈振荡后的洗脱液虽然表现出一定的血凝效价，但接种鸡胚后，病毒并不增殖，说明材料具有明显的催化病毒灭活性能；对细胞毒性极低的材料可以用在与人体接触的防护材料和设施中．筛选出的性能优异的催化材料，拟进一步考察其对SARS病毒的灭活作用．     

细菌生长速率的测定及其热力学性质的研究

细菌生长是一系列非常复杂的生化反应的结果。为了使问题简化、便于采用物理化学的理论和方法对其进行处理,可假设细菌在培养基中的分裂、生长分为三个阶段进行。首先是底物进行扩散,并与细菌表面的活性物质进行作用(如输运过程);其次是细菌将底物吸收到细胞内形成细胞-底物复合物;然后是细胞-底物复合物在其内部一系列酶的作用下产生酶促反应,进行分裂生长和排出代谢产物。现用下式表示:     

Effect of γ-radiation on ointment cold cream

In this paper, Co-60γ ray was used to irradiate the ointment cold cream at room temperature (25°C). We also used FTIR, GC and thin film chromatogram to analyse various irradiated samples. It was found that the ointment cold cream can be irradiated at dose of 5–35 kGy and at dose rate from 0.2 to 0.6 kGy/h at room temperature (25°C) without evident decomposition. At dose of 5–15 kGy, the number of bacteria can be reduced to hygienic standard value. The radiation sterilization is a safe method for killing the bacteria in the ointment cold cream.     

Rapid determination of underivatized pyroglutamic acid, glutamic acid, glutamine and other relevant amino acids in fermentation media by LC-MS-MS

Determination of amino acids in a complex matrix without derivatization is advantageous, however, difficulties are found in both the detection and the separation of those compounds. In this study, a rapid and reliable LC-MS-MS method for the quantitation of underivatized amino acids in exocellular media was established. Injections were made directly after centrifugation of the samples, without further preparation. The separation of seven underivatized amino acids was achieved on a reversed-phase C18 column with pentadecafluorooctanoic acid as a volatile ion-pair reagent, and the specific detection of most amino acids was achieved by MS-MS of the specific transitions [M + H]+-->[M + H - 46]+. The calibration curves of all analytes were linear over the range of 1.0-1000 microg ml(-1) and the detection limits ranged from 0.1 to 5 ng ml(-1), with an injection volume of 20 microl. The inter-day and intra-day precisions ranged from 2.6 to 5.7% and 4.8 to 8.2%, respectively; the mean recoveries of the seven analytes were 81-104%, 91-107% and 93-101% respectively at the spiked level of 10, 40 and 200 microg ml(-1). A large number of fermentation samples were analysed using this method. The technique is simple, rapid, selective and sensitive, and shows potential for the high-throughput quantitation of amino acids from other biological matrices.