Preparation of chiral stationary phase via activated carbamate intermediate for liquid chromatographic optical resolution

Summary Chiral stationary phases (CSPs) for liquid chromatography were prepared by the way of an activated carbamate intermediate. The amino group of aminopropylsilyl silica gel was first activated by carbamylation with disuccinimido carbonate (DSC). The obtained activated carbamate silica gel (ACsil) proved useful as an intermediate for the preparation of urea-type CSPs. The reaction of ACsil with (S)- of (R)-1-(α-naphthyl)-ethylamine gave naphthylethylurea type CSPs. These CSPs were also obtained directly from aminopropylsilyl silica gel by its reaction with optically active (S)- or (R)-succinimido 1-(α-naphthyl)ethyl carbamate (SINEC). Several phenylthiohydantoin amino acid enantiomers and p-bromophenylcarbamyl amino acid enantiomers were resolved on the CSPs by elution with aqueous mobile phase.     

6—磺酰氯香豆素用作发光标记物的初探

过量C6SCl与丙氨酸在pH 9.11(H_3BO_3-NaOH)缓冲体系中,40℃反应40min,经乙酸乙酯萃取分离后,点样在层析聚酰胺膜上,用甲酸+水(1+1)展开,衍生产物得到很好的分离。斑点经1 mol·L~(-1)NaOH喷雾,紫外灯预光照10 min和干燥后,荧光强度与在4～60×10~(-11)mol范围内的丙氨酸量呈良好线性关系。在滤纸基质上,以Pb(AC)_2作重原子微扰剂,标记产物还能产生较强的室温磷光发射。研究表明,C6SCl不仅能作为氨基酸等的荧光标记物,而且可望作为其室温磷光的标记物。     

目视催化褪色计时法测定超痕量钒的研究

本文基于在酸性介质中钒(V)催化溴酸钾氧化酸性铬蓝K褪色的新指示反应,建立了一个催化褪色计时法测定超痕量钒的新方法。在体系中引入活化剂抗坏血酸,灵敏度达2×10~(-12)ng/ml,测定范围在0.0l～3.0ng/ml,同时探讨了反应机理。确立了反应速率方程,方法简便经济,已用于天然水中痕量钒的测定。     

INFLUENCES OF ACID POST-TREATMENT ON THE MORPHOLOGY OF SOAPFREE P（MMA-EA-MAA） PARTICLES PREPARED BY SEEDED EMULSION POLYMERIZATION

Soap-free poly（methyl methacrylate-ethyl acrylate-methacrylic acid） latex particles with narrow size distribution were synthesized by seeded emulsion polymerization, and the porous particles were created by a stepwise alkali/acid treatment method. Effects of acid treatment conditions on the particle morphology were investigated. Results show that one to three pores were formed inside most of particles after post-treatment. At pH 7.0, when the treatment temperature was lower than 70℃, the size of particles and the volume of pores remained almost unchanged, and these two values increased significantly when the temperature was higher than 70℃. Both the particle size and the pore volume decreased with the increase of initial pH value and treatment time in the acid treatment. As the pH was below 4.0 and the treatment time was longer than 180 min, the particles shrunk in size.     

从α－蒎烯直接催化酯化高选择性地合成乙酸正龙脑酯的研究－催化剂与反应机理初探

本文提出了新的硼酸类催化剂体系ＨＢ，用该体系对α－蒎烯与无水乙酸相互作用直接合成乙酸正龙脑酯作了较系统的研究。反应得到两种系列产物－酯化产物和异构化产物，酯化产物主要是乙酸正龙脑酯，葑醇酯和松油酯，异构化产物主要是莰烯、烯和松油烯等，总酯化产率为５０％以上，其中乙酸正龙脑酯为２０％以上，是至今从α－蒎烯直接合成乙酸正龙脑酯的最好结果。通过对产物的￣１ＨＮＭＫ图谱分析及动力学考察，确证反应主产物是正龙脑酯而不是异龙脑酯。文章对Ｈ＿２ＳＯ＿４、ＨＣｌＯ＿４、多聚磷酸（ＰＰＡ）和杂多酸（１２－磷钨酸）等催化剂进行了实验考察、对比和评述，表明了自制的ＨＢ催化剂体系具有高选择性合成乙酸正龙脑酯的显著优点，并对其反应机理作了初步探讨。     

Solubility of α-amino acids in water under high pressure: glycine, -alanine, -valine, -leucine, and -isoleucine

The solubility of glycine, -alanine, -valine, -leucine, and -isoleucine in water was measured at 298.15 K and pressures up to 400 MPa. The standard deviation of the logarithm of the solubility is 0.001–0.003, equal to or better than the accuracy of atmospheric pressure measurement in the literature (0.001–0.05). A variety of solubility phenomena were observed. The solubility of glycine decreased with increasing pressure, whereas that of -alanine increased. The -valine and -isoleucine have a solubility maximum at around 100 MPa, and -leucine seems to exhibit a solid-phase phase transition at around 200 MPa. Pressure coefficient of the solubilities at 0.10 MPa is compared with that thermodynamically estimated in reference to aqueous density measurements of glycine and -alanine at 298.15 K and 0.10 MPa, supporting a reliability of our high-pressure measurements.     

Metabolomic-based investigation of Yinlan alleviating hyperlipidemia by inhibiting blood stasis and phlegm turbidity through the PXR-CYP3A4-ABCB1-FXR pathway

Yinlan lipid regulatory capsule (YL) is a composite traditional Chinese medicine (TCM) new drug to alleviate hyperlipidemia, while its therapeutic mechanism in vivo was not clarified with nontargeted metabolomics investigation. An animal model was established in rats fed a high-fat diet, and their body weights, body mass index (BMI) and blood cholesterol levels were measured. Serum, liver and kidney tissue samples were also extracted for PXR-CYP3A4-ABCB1-FXR signaling pathway research using PCR and UHPLC–MS. The obtained plasma samples were analyzed by UHPLC-Q-TOF-MS metabolomic investigation, which revealed PXR-CYP3A4-related metabolites and changes induced by YL. Finally, the key metabolites were chosen as index components, and their levels in the serum, liver, small intestine and bile were used for simultaneous UHPLC–MS-MS determination. The results indicated that YL was effective in rebalancing blood TG and TC levels (compared to controls). With respect to the PXR-CYP3A4-ABCB1 pathway, as a result of YL’s effect, gene expression or activity of the two targets decreased significantly in both the liver and kidney. The same trend was observed in the serum samples mentioned above. Metabolomics screening and data revealed that 44 metabolites can be regarded as biomarkers related to hyperlipidemia, fatty acids synthesis, and body energy consumption, as well as synthesis, transportation and exertion of cholesterol. YL’s treatment focused on 26 of them, primarily bile acids, indicating that the antihyperlipidemic effect of this drug lies in its inhibitory activity of cholesterol metabolism. Subsequent analysis of those in vivo components revealed that significant increases (compared to the model group) occurred in the blood, liver, small intestine and bile in groups that received medium and high doses of YL (while the low dose was relatively unchanged). Those target components exhibit a close relationship with PXR and/or CYP3A4. The use of YL repressed PXR expression and subsequently decreased CYP3A4 activity. As a result, synthesis of related bile acids increased, while cholesterol levels decreased, consequently leading to the attenuation of hyperlipidemia. This study comprehensively investigated the antihyperlipidemia mechanism of YL based on its repression of PXR-CYP3A4 activity and related metabolite yield, establishing an accurate method for evaluating the therapeutic effect of YL.     

双羟基极性键合固定相在氨基酸分析上的应用

我们曾报道了一类新型双羟基键合固定相(GDSB)的合成,研究表明这类固定相具有键合相浓度高,热和化学稳定性好的特点,可用于性质相似的有机化合物的分离。 本文以GDSB为色谱柱填料,含Cu~(2+)离子和烷基磺酸盐的HAc-NaAc缓冲溶液作流动     

各种氨基酸衍生物在Chirasil—Val固定相上的气相色谱分离

本文叙述氨基酸及其对映体的全氟酰基烷基脂(O-异丙基、-异丁基、-正丁基;N(O,S)-三氟乙酰基,TFA、-七氟丁酰基,HFB)在Chirasil-Val上的洗脱特性。随烷基取代增大,保留时间增加;用HFB代替TFA,对映体的分离因子降低。此外,DL-氨基酸与另丁醇衍生,生成的对映及非对映衍生物在Chirasil-Val上可拆分成四个色谱峰。     

酸性品红与蛋白质结合反应的研究及应用

在pH1.4的Clark-Lubs缓冲介质中，蛋白质与酸性品红反应形成结合物，该结合物的最大吸收波长为576nm，与酸性品红相比，红移了34nm。据此拟定了分析方法，制定了牛血清白蛋白(BSA)、人血清白蛋白(HAS)、γ-球蛋白(γ-G)和酪蛋白的工作曲线，测定的摩尔吸光系数均在10^5数量级，用于人血清中总蛋白的测定，结果与溴甲酚绿(BCG)法基本一致。