Synthesis of a silica-bonded bovine serum albumin s-triazine chiral stationary phase for high-performance liquid chromatographic resolution of enantiomers

A novel method of synthesizing protein chiral stationary phase (protein-CSP) is proposed with 2,4,6-trichloro-1,3,5-triazine as the activator. The bovine serum albumin (BSA) based chiral columns (150x4.6 mm I.D.) were prepared successfully within 8 h. With tryptophan as the probe solute, it was observed that the BSA immobilized by this method had a better ability to distinguish enantiomers than that activated by glutaric dialdehyde. This may be due to the well-maintained BSA conformation and the larger amount of BSA immobilized on the silica gel. The BSA-CSP prepared by this method was relatively stable under experimental conditions, and the resolution of 13 chiral compounds was achieved. The coupling reaction in this method is mild, reliable and reproducible; it is also suitable for the immobilization of various biopolymers in the preparation of bioreactor, biosensor and affinity chromatography columns. (C) 2000 Elsevier Science B.V. All rights reserved.

Fractionation and analysis of Artemisia capillaris Thunb. by affinity chromatography with human serum albumin as stationary phase

A method for the screening and analysis of biologically active compounds in traditional Chinese medicine is proposed. Affinity chromatography using a human serum albumin (HSA) stationary phase was applied to separate and analyze the bioactive compounds from Artemisia capillaris Thunb. Five major peaks and several minor peaks were resolved based on their affinity to HSA, two of them were identified as scoparone (SCO, 6,7-dimethoxycoumarin) and capillarisin (CAP). CAP shows a much higher affinity to HSA than SCO. The effects of acetonitrile concentration, eluent pH, phosphate concentration and temperature on the retention behaviors of several major active components were also investigated, and it was found that hydrophobicity and eluent pH play major roles in changing retention values. The results demonstrate that the affinity chromatography with a HSA stationary phase is an effective way for analyzing and screening biologically active compounds in traditional Chinese medicine. (C) 2000 Elsevier Science B.V. All rights reserved.

Alkaline treatment of the cellulose fiber affecting membrane column behaviour for high-performance immunoaffinity chromatography

The original cellulose fibers and those treated by alkaline solution were both used to prepare the acrylic membranes. The two kinds of membranes were packed into the columns for high-performance immunoaffinity chromatography by the immobilization of protein A on them. It was observed that the alkaline treatment of the cellulose fiber decreased the pressure resistance of the membrane to the mobile phases and greatly increased the accessible volume to the proteins, but affected the adsorption capacity of human IgG on the protein A membrane columns less. There is little difference between those two kinds of membranes on the adsorption capacities of HIgG, which means that the alkaline treatment of the cellulose fiber only significantly changes the void volume inter-membrane, and the porosity and surface area of membrane less. Alkaline treatment of the cellulose fiber reduced the membrane-column efficiency significantly. Some typical examples for the immunoaffinity analysis of IgG from human and dog plasma on the protein A membrane columns are illustrated. Copyright (C) 2000 John Wiley & Sons, Ltd.

Ferrocenylphosphine-imine ligands for Pd-catalyzed asymmetric allylic alkylation

Ferrocenylphosphine-imine ligands 6 derived front (R,S)-PPFNH2-R 5 and a variety of benzaldehydes were applied in the Pd-catalyzed asymmetric allylic alkylation of 1,3-diphenylprop-2-en-1-yl acetate 7a or pivalate 7b with dimethyl malonate. The substituent effects on the catalytic reaction were investigated, and 96% e.e. with 99% yield was achieved when the m-nitro substituted ligand 6k was used. (C) 2002 Elsevier Science Ltd. All rights reserved.

Highly enantioselective resolution of terminal epoxides using polymeric catalysts

Poly-salen-Co(III) complexes were employed in the hydrolytic kinetic resolution (HKR) of terminal epoxides and ee's up to 98% were obtained. In the HKR of epichlorohydrin, the polymeric catalysts can be recovered and modified for recycling. The recovered polymer catalyst shows good activity and selectivity. (C) 2002 Elsevier Science Ltd. All rights reserved.

Screening and analysis of biologically active compounds in Angelica sinensis by molecular biochromatography

A novel strategy for the screening and analysis of biologically active compounds in traditional Chinese medicine by molecular biochromatography is proposed. Molecular biochromatography with human serum albumin (HSA) immobilized on silica as stationary phase was used to screen and analyse the bioactive compounds in the typical Chinese medicine of Angelica sinensis (Oliv.) Diels. Ten peaks showed retention on this column, which is based on their affinity for HSA. Ferulic acid and liguistilide were identified as the principal active components, which agrees very well with the results in the literature. A quality control method was also developed based on the simultaneous determination the concentrations of ferulic acid and liguistilide in solutions of Angelica sinensis (Oliv.) Diels extracted with water and methanol. It was observed that the concentrations of ferulic acid and liguistilide in solution extracted with methanol were 2 and 53 times higher, respectively, than those with water. It was shown that molecular biochromatography is an effective way of analysing and screening biologically active compounds in traditional Chinese medicine.

Drug-protein interaction studied by technique of microdialysis combined with high performance liquid chromatography

Drug-protein binding is an important process in determining the activity and fate of a pharmaceutical agent once it has entered the body. This review examines the method of microdialysis combined with high-performance liquid chromatography (HPLC) that has been developed;by ours to study such interactions, in which the microdialysis was applied to sample the free drug in the mixed solution of drug with protein, and HPLC to quantify the concentration of free drug in the microdialysate. This technique has successfully been used for determining various types of binding interactions between the low affinity drugs, high affinity drugs and enantiomers to HSA. For the case of competitive binding of two drugs to a protein in solution, a displacement equation has been derived and examined with four nonsteroidal anti-inflammatory drugs and HSA as model drugs and protein, respectively. Microdialysis with HPLC was adopted to determine simultaneously the free solute and displacing agent in drug-protein solutions. The method is able to locate the binding site and determine affinity constants even up to 10(7) L/mol accurately.

Synthesis of chiral 3-acylcamphors

3-Acylcamphors were synthesized in moderate yields by the condensation of camphor with esters using sodium hydride as a base.

An efficient synthesis of dicyclohexylmethyl diazoacetate

Dicyclohexylmethyl diazoacetate was synthesized in excellent yield from the corresponding glycinate. which was derived in high yield from dicyclohexylmethyl chloroacetate via azide substitutuion, and reduction.

Highly efficient copper-catalyzed N-arylation of alkylamines with aryl iodides using phosphoramidite as ligand

A mild and highly efficient copper-catalyzed system for N-arylation of alkylamines with aryl iodides using binaphthol-based phosphoramidites as ligands was developed. The phosphoramidite ligands are stable, cost-effective and easily prepared from inexpensive, commercially available starting materials using a simple, efficient method. (c) 2005 Elsevier B.V. All rights reserved.

A highly active palladium-phosphoramidite catalyst for the Suzuki cross-coupling of aryl bromides

A highly efficient palladium-catalyzed Suzuki coupling of aryl bromides with aiylboronic acids using phosphoramidite ligand 2c was developed. The phosphoramidite ligands are cost-effective and easily prepared from inexpensive, commercially available starting materials using a simple, efficient method. It represents an advance toward the discovery of low-cost catalyst systems for eventual availability. (c) 2005 Elsevier B.V. All rights reserved.

Comparative X-ray photoelectron spectroscopic study on the desulfurization of thiophene by Raney Nickel and rapidly quenched skeletal nickel

The desulfurization of thiophene on Raney Ni and rapidly quenched skeletal Ni (RQ Ni) has been studied in ultrahigh vacuum (UHV) by X-ray photoelectron spectroscopy (XPS). The Raney Ni or RQ Ni can be approximated as a hydrogen-preadsorbed polycrystalline Ni-alumina composite. It is found that thiophene molecularly adsorbs on Raney Ni or RQ Ni at 103 K. At 173 K, thiophene on alumina is desorbed, while thiophene in direct contact with the metallic Ni in Raney Ni undergoes C-S bond scission, leading to carbonaceous species most probably in the metallocycle-like configuration and atomic sulfur. On RQ Ni, the temperature for thiophene dissociation is about 100 K higher than that on Raney Ni. The lower reactivity of RQ Ni toward thiophene is tentatively attributed to lattice expansion of Ni crystallites in RQ Ni due to rapid quenching. The existence of alumina and hydrogen may block the further cracking of the metallocycle-like species on Raney Ni and RQ Ni at higher temperatures, which has been the dominant reaction pathway on Ni single crystals. By 473 K, the C Is peak has disappeared, leaving nickel sulfide on the surface.

Prediction of 30-day mortality in older patients with a first acute myocardial infarction

This study sought predictors of mortality in patients aged >or=75 years with a first ST-segment elevation myocardial infarction (STEMI) and evaluated the validity of the GUSTO-I and TIMI risk models. Clinical variables, treatment and mortality data from 433 consecutive patients were collected. Univariable and multivariable logistic regression analyses were applied to identify baseline factors associated with 30-day mortality. Subsequently a model predicting 30-day mortality was created and compared with the performance of the GUSTO-I and TIMI models. After adjustment, a higher Killip class was the most important predictor (OR 16.1; 95% CI 5.7-45.6). Elevated heart rate, longer time delay to admission, hyperglycemia and older age were also associated with increased risk. Patients with hypercholesterolemia had a significantly lower risk (OR 0.46; 95% CI 0.24-0.86). Discrimination (c-statistic 0.79, 95% CI 0.75-0.84) and calibration (Hosmer-Lemeshow 6, p = 0.5) of our model were good. The GUSTO-I and TIMI risk scores produced adequate discrimination within our dataset (c-statistic 0.76, 95% CI 0.71-0.81, and c-statistic 0.77, 95% CI 0.72-0.82, respectively), but calibration was not satisfactory (HL 21.8, p = 0.005 for GUSTO-I, and HL 20.6, p = 0.008 for TIMI). In conclusion, short-term mortality in elderly patients with a first STEMI depends most importantly on initial clinical and hemodynamic status. The GUSTO-I and TIMI models are insufficiently adequate for providing an exact estimate of 30-day mortality risk.

The relevance and admissibility of prior sexual history with the defendant in sexual offence cases

Kibble, N, ?The Relevance and Admissibility of Prior Sexual History with the Defendant in Sexual Offence Cases? (2001) 32 Cambrian Law Review 27-63 (cited with approval by HL in R v A(2) [2002] AC 45) RAE2008