Inhibition of Metalloproteinase Activity by Chinese Formulations Used to Treat Inflammatory Diseases

Introduction Matrixmetalloproteinases(MMPs)areaclassof zinc requiringextracellularendopeptidasesthatcanto getherdegradeallcomponentsoftheextracellularma trixandbasementmembranes[1—3].Theyplayimpor tantrolesinconnectivetissueremodeling,occurringin normalb…     

具有生物活性的有机磷化合物的研究V，α－［（取代）芳氧基乙酰氧基］烷基膦酸酯的合成和性质

过取代苯氧乙酰氯和α－羟基烷基胰酸酯的缩合反应合成了８种标题化合物，用元素分析，红外，核磁及质谱作了表征，测定了它们的除草活性和植物生长调节活性。     

Oxidation of bridging groups by carboxylate coordinated ligands in palladium clusters

Thermolysis of tetranuclear palladium clusters Pd₄(-Q)₄ Pd₄(-Q)₄(-O₂CR)₄ (Q=CPh₂ or CO;R=Me, CMe₃, Ph, CH₂Cl or CF₃) has been found to involve innersphere oxidation of carbene or carbonyl ligands during which an oxygen atom transfer occurs from the carboxylate group to the carbene or carbonyl ligand. The thermolysis of the carbonyl clusters gives rise to the products of CO₂ insertion into the C–H bond of benzene or toluene used as solvents forming benzoic acid from benzene and a mixture of phenylacetic and toluic acids from toluene. The reaction of [Pd(OAc)₂(PPh₃)]₂ with HCO₂H includes the transfer of an O atom from formate ligand to the P atom and cleavage of the P-Ph bond accompanied by transfer of the Ph group from PPh₃ ligand to the palladium atom. The structure of the complex formed, [Pd(-O₂PPh₂)(C₆H₅)(PPh₃)]₂, has been resolved by X-ray analysis.     

Intramolecular Catalysis in Reactions of Hydroxamic Acids

Among hydroxamate ions (typical nucleophiles), anomalously high nucleophilicity relative to 4-nitrophenyl diethyl phosphonate is seen in anions which have general basic catalytic sites that provide anchimeric assistance for proton transfer in the transition state.     

血小板阻聚药物中间体N-环己基-5-氯丁基-1H-四氮唑的合成

以δ-戊内酯和环己胺为原料合成了抗血小板聚集药物西洛他唑的重要中间体N-环己基-5-氯丁基-1H-四氮唑，选择了合适的相转移催化剂及安全的叠氮试剂并获得较高的收率。     

The Overman rearrangement in carbohydrate chemistry: stereoselective synthesis of functionalized 3-amino-3,6-dihydro-2H-pyrans and incorporation in peptide derivatives

A stereocontrolled synthesis of an unsaturated sugar bearing two amino groups (one of them masked as an azide), using an Overman rearrangement as key step, is described. This scaffold is used to prepare two peptides having aromatic fragments, which have shown activity as calpain inhibitors.     

Stereoselective synthesis of procyanidin B3-3-O-gallate and 3,3″-di-O-gallate, and their abilities as antioxidant and DNA polymerase inhibitor

A simple method for the synthesis of procyanidin B3 substituted with a galloyl group at the 3 and 3″ position is described. Condensation of a benzylated catechin-3-O-gallate electrophile with a nucleophile, catechin and catechin-3-O-gallate, proceeded smoothly and stereoselectively to afford the corresponding dimer gallates, procyanidin B3-3-O-gallate and procyanidin B3-3,3″-di-O-gallate, in good yields. Further, their antioxidant activities on UV-induced lipid peroxide formation, DPPH radical scavenging activity and inhibitory activity of DNA polymerase were also investigated. Among three procyanidin B3 congeners (procyanidin B3, 3-O-gallate and 3,3″-di-O-gallate), the 3,3″-di-O-gallate derivative showed the strongest antioxidant and radical scavenging activity. Interestingly, the 3-O-gallate derivative was the strongest inhibitor of mammalian DNA polymerase with IC₅₀ value of 0.26 μM, although it showed the weakest antioxidant and radical scavenging activity. It became apparent that the presence of a galloyl group at the C-3 position in the proanthocyanidin oligomer was very important for biological activity, however, the antioxidant activity of these compounds was not parallel to the DNA polymerase inhibitory activity.     

合成产物PEPAMP及其副产物的电喷雾串联质谱分析

PEPAMP是应用于工业循环水中的新一代高效阻垢剂.采用电喷雾电离质谱和质谱/质谱技术分析了合成产物,注射泵直接进样,正离子方式检测,方法简便、快速.通过EI-MS技术获得了目标产物PEPAMP及主要副产物的准分子离子峰,通过ESI-MS-MS技术获得了其碎片信息,并对目标化合物及主要副产物进行了精确质量测定,确定了目标化合物及主要副产物的结构.     

Enhanced selectivity for inhibition of analog-sensitive protein kinases through scaffold optimization

The ability to inhibit any protein kinase of interest with a small molecule is enabled by a combination of genetics and chemistry. Genetics is used to modify the active site of a single kinase to render it distinct from all naturally occurring kinases. Next, organic synthesis is used to develop a small molecule, which does not bind to wild-type kinases but is a potent inhibitor of the engineered kinase. This approach, termed chemical genetics, has been used to generate highly potent mutant kinase-specific inhibitors based on a pyrazolopyrimidine scaffold. Here, we asked if the selectivity of the resulting pyrazolopyrimidines could be improved, as they inhibit several wild-type kinases with low-micromolar IC₅₀ values. Our approach to improve the selectivity of allele-specific inhibitors was to explore a second kinase inhibitor scaffold. A series of 6,9-disubstituted purines was designed, synthesized, and evaluated for inhibitory activity against several kinases in vitro and in vivo. Several purines proved to be potent inhibitors against the analog-sensitive kinases and exhibited greater selectivity than the existing pyrazolopyrimidines.     

Protein Prenylation: An (Almost) Comprehensive Overview on Discovery History, Enzymology, and Significance in Physiology and Disease

Summary. Since 1979, when prenylation has been first discovered as chemical oddity of a yeast mating factor, the two forms of this posttranslational modification of proteins (farnesylation and geranylgeranylation) have been found as wide spread among proteins from Eukarya and their viruses. This review attempts to summarize as comprehensively as possible the enzymological processes of prenylation and the various aspects of their biological significance. The substrate proteins of prenyltransferases are known to carry a sequence signal composed of a cysteine-containing 4–5 residue stretch at the utmost C-terminal end that is N-terminally preceded by a flexible and polar linker region of ca. 10 residues. Postprenylation processing of substrate proteins can involve C-terminal proteolysis, C-terminal carboxyl methylation, and other steps of maturation. The prenyl anchor functions as module for membrane attachment or for protein–protein interaction. Prenyl anchor carrying proteins fulfill a large array of functions in signaling and regulation of cellular processes. Therefore, they are involved in the pathogenesis of a variety of human diseases, the most prominent one being cancer. Farnesyltransferase inhibitors show surprisingly high efficiency in controlling tumor growth in model systems but, so far, clinical trials with human patients have remained without the desired success. Interference into prenylation pathways appears also a promising treatment principle in a variety of parasitic diseases.