Dissectol A,A Novel Monoterpene Glycoside from Incarvillea dissectifoliola

Dissectol A,a novel monoterpene glycoside was isolated from the methanol part of the 95% EtOH extract of Incarvillea dissecfoliola and its structure was determined by 1D and 2D NMR data.     

Effect of metal ions on enantioseparation of five amino acids by ligand exchange capillary zone electrophoresisEI北大核心CSCD

Enantioseparation of five amino acids was conducted by chiral ligand exchange capillary zone electrophoresis (CLE-CZE). L-His and different metal ions in a certain proportion were used to form chiral recognition complexes. The enantiomers were exchanged with L-His ligands in the complex. Then, the separation of enantiomers was obtained according to the different ligand exchange ability. Effects of the valence and the electron layers of metal ions on the resolution were investigated systemically. Baseline separation of D, L-Phe, D, L-Tyr and D, L-Trp was obtained within 12 min when 4 mmol/L Co(Ⅱ) and 8 mmol/L L-His were added to the phosphate buffer solution (20 mmol/L, pH 8.0). The resolutions of D, L-Phe, D, L-Tyr and D, L-Trp were 1.53, 2.04, and 1.58, respectively. Partial chiral separation of D, L-Ser and D, L-Val was achieved under the same conditions. When Co(II) was used as the central ion, the resolution was better than that of Cu(II) and Zn(II), although they had the same number of electron layers and valence. The resolution of amino acids with Ag(I) as the central ion was not as good as that of divalent metal ions. Metal ions with three electron layers had better separation results than that with four electron layers. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Hydrolysis of epoxides and aziridines catalyzed by polymer-supported quarternary ammonium bisulfate

Macroporous resin （D201）-supported quartemary ammonium bisulfate （D201-HSO4） was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the corresponding 1,2-diols and β-amino alcohols in high yields. The catalyst was facilely prepared and recyclable.     

A new cytotoxic caged polyprenylated xanthone from the resin of Garcinia hanburyi

A new caged polyprenylated xanthone, gambogic aldehyde （1）, was isolated from the resin of Garcinia hanburyi. Its structure was elucidated on the basis of spectral data including 1D and 2D NMR data. In addition, the antiproliferative ability of compound 1 was determined in mouse leukemia P388 and P388/ADR cells.     

A New Triterpenoid from Doellingeria scaber

A new oleanane-type triterpene was isolated from the roots ofDoellingeria scaber. Itsstructure was identified as 3-oxo-16ct-hydroxy-olean-12-en-28-oic acid based on 1D and 2D NMRspectroscopy and X-ray analysis.     

POTENTIATED EFFECT OF VAGAL STIMULATION AND HORMONAL AGENTS ON PANCREATIC EXOCRINE SECRETION IN DOGS

Chronic experiments were made on eighteen dogs with Thomas pancreatic fistula andgastric fistula. Both in chronic and acute experiments the degenerated right cervical vagusnerve was stimulated by electrical shock and the endogenous secretin and CCK was releasedby means of duodenal acidification (D. A.). The exogenous secretin, atropine and lidocainewere infused to analyse the interrelationship of neurohormones in the pancreatic exocrinesecretion. The results were as follows. In chronic experiments the pancreatic secretory la-tency was shorter and volume larger than that in acute experiments induced by D. A. Thedifference is very significant (P<0.001). Both vagotomy and atropine significantly inhibitedpancreatic secretion induced by D. A. (P<0.01). Lidocaine infused into duodenum inhibitedpancreatic secretion induced by D. A. as well. When vagal stimulation was combined withD. A., either simultaneously or successively, the pancreatic secretion was increased morethan the additive sum obtained by separate     

A new triterpenoid saponin from Clematis ganpiniana

A new triterpenoid saponin,named clematiganoside A(1),was isolated from the whole plant of Clematis ganpiniana.Its structure was elucidated on the basis of 1D,2D NMR,TOF-MS and ESI-MS techniques,and physicochemical properties.     

EXTRACTION AND SEPARATION OF RADISH RED PIGMENT FROM A WASTE WATER OF SALTING RADISH BY D61 RESIN

Extraction and separation of Radish red pigment from a waste water of salting Radish was studied on D61 resin.The exchange capacity of adsorption the pigment was equal to 60.91mg&#183;g^-1 wet resin,and the equilibium time only 40mins.All Radish red pigment adsorbed on D61 resin was eluted using a eluent in which concentraction of HCl or alcohol was 0.1mol&#183;L^-1 or 80% at 50℃ when the flow rate was at 2BV&#183;hm^-1.Stability of D61 resin was very well,and while the resin was recycled fifteen times, the exchange capacity was only decreased 11.9%,and the exchange capacity didn′t changed.Because of negative ion of mustard oil,it could′t be adsorbed on the resin.Finally, a paste product with yield of 1.96mg&#183;100ml^-1 waste water was obtained after alcohol evaporation and vacuum drying.     

An unusual bioactive oleanane triterpenoid from Rhododendron campanulatum D.Don

An unusual oleanane triterpene(1) was isolated from aerial parts of Rhododendron campanulatum.The compound had shown prominent antibacterial and immunomodulatory activities.The structure of the compound was determined by spectroscopic data including 1D and 2D NMR spectral analysis.     

A NEW ALKALOID FROM CELASTRUS ANGULATUS

A new β-dihydroagarofuran alkaloid Ⅰ was isolated fromCelastrus angulatus.The structure was established on the basis of 1D and 2DNMR analysis,and x-ray diffraction.     

Quantification of D‐Asp and D‐Glu in rat brain and human cerebrospinal fluid by microchip electrophoresis

A microchip electrophoresis (MCE) method with LIF detection was presented for quantification of D ‐aspartic acid (D ‐Asp) and D ‐glutamate (D ‐Glu) in biological samples. D ‐Asp and D ‐Glu were determined after precolumn derivatization with FITC. The chiral separation was performed on a glass/PDMS hybrid microfluidic chip using γ‐CD as chiral selector in the running buffer. High sensitive detection was obtained by the LIF detection. The LODs (S/N = 3) for D ‐Asp and D ‐Glu were 6.0×10^–8 and 4.0×10^–8 M, respectively. Using this method, the levels of D ‐Asp and D ‐Glu in rat brain and human cerebrospinal fluid (CSF) were determined.     

C_(78)~n离子的Jahn-Teller畸变和电子光谱

用INDO系列方法对C78n(D3、D3h、D?h)进行系统研究,表明C78(D3)比C78(D3h、D?h)稳定,与理论计算及实验结果一致;且随n绝对值增大,C78n总能量升高;C78n(D3、D3h、D?h)异构体的部分离子发生了Jahn-Teller畸变.以优化构型为基础,用INDO/SCI方法首次计算了C78n的电子光谱,对电子跃迁进行理论指认,讨论C78n光谱的特征吸收与C78相比发生红移的原因.     

Structural identification of degradants of moexipril by LC–MS/MS

A gradient LC–MS method was developed for the identification and characterization of degradants of moexipril using liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS). Moexipril was subjected to hydrolysis (acid, base and neutral), oxidation, photolytic and thermal degradation conditions as mentioned in ICH guidelines Q1A (R2). The drug degraded under hydrolysis, oxidation and photolytic conditions, but it was stable under thermal conditions. In total, five degradants were formed and separated on an Agilent XDB C‐18 column (4.6 × 150 mm, 5 μm) in a gradient elution method. Four degradants ( D1 , D2 , D4 and D5 ) under acidic conditions, three degradants ( D2 , D3 and D4 ) under basic conditions and three degradants ( D1 , D4 and D5 ) under neutral and oxidative stress conditions were formed. In addition, two degradants ( D4 and D5 ) were formed under photolytic stress conditions. To elucidate the structures of degradants, fragmentation of moexipril and its degradants was studied using LC–MS/MS experiments and accurate mass measurements (HRMS) data. The fragment ions in the product ion tandem mass spectra of all the degradants were compared with those of moexipril and assigned the probable structures for the degradants.     

Synthesis and mesomorphism of novel multi-arm liquid crystals with cholic acid as chiral centre linking Schiff base moieties as mesogens

A new series of multi-arm chiral liquid crystals (LCs) D1–D3 were synthesised and characterised. Cholic acid was used as the core and ω-[4-(p-alkoxybenzoloxy)phenoxycarbonyl]valeric acid (B1–B3) was used as the mesogenic arms, containing different terminal substituent X (B1: X= -OCH₃, B2:X= -CH₃, B3: X= -Cl). Their structures and mesomorphic properties were investigated by Fourier-transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrometer, differential scanning calorimetry, polarised optical microscopy and X-ray diffraction, respectively. The mesogenic B1–B3 displayed smectic B phase. The multi-arm LC D1 displayed cholesteric, while D2 and D3 exhibited nematic phase. The formation of cholesteric phase of D1 was affected by both the chiral core – the bulky cholic acid and the polarity of the terminal substituent of the mesogenic arm. That D1 displayed cholesteric phase but D2–D3 did not indicated that the stronger polarity of the terminal group OCH₃ of D1 played an important part in stabilising the cholesteric phase. The multi-arm LCs D1–D3 all showed ultraviolet activity. The wavelength of maximum absorption of D1–D3 was affected by the terminal substituent of the mesogenic arm.     

Solvent extraction of zinc from sulphate leaching solution of a sulphide-oxide sample using D2EHPA and Cyanex 272

Solvent extraction of zinc from sulphate leach solution obtained from the treatment of a sulphide-oxide sample, was investigated using D2EHPA and Cyanex 272 diluted in kerosene in a batch reactor. According to the results, D2EHPA exhibited the higher extraction efficiencies than Cyanex 272 at the organic/aqueous ratio of 1:1. The optimum concentration and pH for D2EHPA and Cyanex 272 were distinguished to be 0.5?mol/L and 2.5, and 0.035?mol/L and 3.5, respectively. Under these conditions, extraction efficiency was found to be ～75% for D2EHPA against 41% for Cyanex 272. The plot of log D versus log [D2EHPA] confirmed the presence of 1 mole D2EHPA in dimeric form for 1 mole Zn in the extraction system. Thermodynamic data showed that the zinc extraction process is endothermic. For D2EHPA, two-stage simulated counter-current extraction experiments were performed on the basis of the McCabe-Thiele diagram and the extraction percentage of zinc was found to be about 88%. The synergistic effect of Cyanex 272 and TBP with D2EHPA was particularly investigated. It was found that the mixture of 80% D2EHPA and 20% Cyanex 272 exhibited the best synergistic effect for Zn-extraction with a synergistic coefficient of 1.04.     

Effect of chain length of some 2D and 3D alkanethiols on gold studied by DSC and voltammetry

Striking similarities and differences in the behaviour of two-dimensional (2D) self-assembled monolayers (SAMs) on gold and corresponding three-dimensional (3D) SAMs on gold of two alkanethiols of different chain lengths, hexadecanethiol (HDM) and octadecanethiol (ODM) were investigated as a function of temperature. Cyclic Voltammetry (CV) of the 2D SAMs and Differential Scanning Calorimetry (DSC) of the 3D SAMs were used to study previously unexplained behaviour. CV revealed two transition temperatures in both the HDM and ODM 2D systems. In the DSC studies, both a lower and higher temperature transition was observed in the 3D SAMs of HDM but only one temperature transition was observed in the 3D SAMs of ODM. It was deduced that the lower temperature transitions in the gold-alkanoate nanoparticles were related to interaction between the methyl group chain ends. The lower temperature transition was observed in the 3D system of HDM but not that of ODM because the curvature in the 3D system that is absent in the 2D system reduces the interaction between the alkyl chain ends due to a longer chain resulting in an increased distance between the end groups. It was concluded that the lower transition temperature was attributed to the disordering of the alkyl chains starting from the end closest to the terminal groups.     

含三乙烯二胺强弱碱功能基阴离子交换树脂的制备及其吸附性能

含三乙烯二胺强弱碱功能基阴离子交换树脂的制备及其吸附性能;三乙烯二胺; 强弱碱基阴离子交换树脂; 滴定曲线; 苯甲酸; 吸附性能     

Solid-state polymerization studies of conjugated diacetylenes deca-2,8-diene-4,6-diyne-1,10-diol and derivatives

The title diacetylenic compound (D3) and its derivatives dibenzoate (D3B), dinitrobenzoate (D3mNB), ditosylate (D3PTS), and diurethane (D3PU) were synthesized and their solid-state reactivity examined under irradiation and thermal stimulation. D3, D3B, and D3PTS crystallized in reactive phases. The thermal and irradiation polymerization behavior of D3 and D3B was examined further by time-conversion curves.     

Analysis of vitamin D and its metabolites using thermospray liquid chromatography/mass spectrometry.

A new method is described for the analysis of vitamin D and its metabolites utilizing thermospray (TSP) mass spectrometry as an on-line detector for high performance liquid chromatography. Ionization conditions were optimized for use with isocratic reversed phase chromatography. TSP mass spectrometry was employed in series with a UV absorbance detector to facilitate comparisons between the two methods of detection. Positive ion TSP mass spectra were recorded for vitamin D2, vitamin D3, 25-hydroxyvitamin D3 (25(OH)D3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3). The spectra contained protonated molecular ions, ammonium adduct ions and fragment ions due to the loss of one or more molecules of water. A comparison of quantitative precision was made by determining UV absorbance and TSP standard curves for vitamin D3 using two different methods: (1) External standard method with post-column (post UV detector) addition of ammonium acetate. (2) As (1) but using the method of internal standards with a closely eluting internal standard (vitamin D2). In each case the quantitative precision (correlation coefficient) for UV absorbance detection was superior owing to intrinsic instability of the TSP ion beam. A stable isotopically labelled internal standard was employed in the development of an assay for 1,25(OH)2D3. The assay was used to quantify in vitro enzymic conversion of 25(OH)D3 to 1,25(OH)2D3 in guinea pig and sheep renal mitochondrial incubations. TSP LC/MS was also applied to analysis of an extract of human blood plasma in which D3 and each of its principal metabolites were identified in a single analysis.     

Anomalous fluorescence from the azaxanthone ketyl radical in the excited state

The time-resolved absorption and fluorescence spectra of the azaxanthone (AX) ketyl radical (AXH.) in the excited state (AXH.(Dn) (n = 1 or 2)) were observed during the nanosecond-picosecond two-color two-laser flash photolysis. AXH. showed dual fluorescence peaks at 460 and 645 nm, which were assigned to the D2 --> D0 and D1 --> D0 transitions, respectively. It was found that the lifetime of the D2 --> D0 fluorescence (1.0 ns) was longer than that of the D1 --> D0 fluorescence (0.4 ns). The fluorescent quantum yields of the D1 --> D0 and D2 --> D0 fluorescence were estimated to be 0.0008 +/- 0.0002 and 0.05 +/- 0.02, respectively. These anomalous emitting properties can be attributed to the pyridine ring in AX. AXH. is a new example of a neutral radical which violates Kasha's rule.