Effects of Hydrogen and Hydrogen Sulfide on Cumene Cracking Catalyzed by Pt/WO3-ZrO2. Control of Acidic and Metallic Functions

Synthesis of alumina aerogels was carried out by hydrolysis of aluminium isopropanolate and butanolate in benzene, methanol and isopropanol solutions as components of support precursors followed by gelation, drying under supercritical conditions and calcination. The influence of the type of precursor and solvent, synthesis temperature as well as drying and calcination temperature on bulk density, specific surface area and total pore volume was investigated.     

Decarboxylation of α-keto carboxylic acids by persulfoxide

Photosensitized oxygenation of diethyl sulfide in the presence of α-keto carboxylic acids caused oxidative decarboxylation of the acids by persulfoxide and gave carboxylic acids, carbon dioxide, diethyl sulfoxide and diethyl sulfone.     

A straightforward approach to antibodies recognising cancer specific glycopeptidic neoepitopes

Aberrantly truncated immature O-glycosylation in proteins occurs in essentially all types of epithelial cancer cells, which was demonstrated to be a common feature of most adenocarcinomas and strongly associated with cancer proliferation and metastasis. Although extensive efforts have been made toward the development of anticancer antibodies targeting MUC1, one of the most studied mucins having cancer-relevant immature O-glycans, no anti-MUC1 antibody recognises carbohydrates and the proximal MUC1 peptide region, concurrently. Here we present a general strategy that allows for the creation of antibodies interacting specifically with glycopeptidic neoepitopes by using homogeneous synthetic MUC1 glycopeptides designed for the streamlined process of immunization, antibody screening, three-dimensional structure analysis, epitope mapping and biochemical analysis. The X-ray crystal structure of the anti-MUC1 monoclonal antibody SN-101 complexed with the antigenic glycopeptide provides for the first time evidence that SN-101 recognises specifically the essential epitope by forming multiple hydrogen bonds both with the proximal peptide and GalNAc linked to the threonine residue, concurrently. Remarkably, the structure of the MUC1 glycopeptide in complex with SN-101 is identical to its solution NMR structure, an extended conformation induced by site-specific glycosylation. We demonstrate that this method accelerates dramatically the development of a new class of designated antibodies targeting a variety of “dynamic neoepitopes” elaborated by disease-specific O-glycosylation in the immunodominant mucin domains and mucin-like sequences found in intrinsically disordered regions of many proteins.

We developed new class of designated antibodies targeting of “dynamic neoepitopes” elaborated by disease-specific O-glycosylation at the immunodominant mucin domains.     

Monomer-isomerization polymerization. XXIII.. Monomer-isomerization polymerization of 5-phenyl-2-pentene with ziegler–natta catalysts

5-Phenyl-2-pentene (5Ph2P) was found to undergo monomer-isomerization polymerization with TiCl₃–R₃Al (R = C₂H₅ or i-C₄H₉, Al/Ti > 2) catalysts to give a polymer consisting of exclusively 5-phenyl-1-pentene (5Ph1P) unit. The geometric and positional isomerizations of 5Ph2P to its terminal and other internal isomers were observed to occur during polymerization. The catalyst activity of alkylaluminum examined to TiCl₃ was in the following order: (C₂H₅)₃Al > (i-C₄H₉)₃Al > (C₂H₅)₂AlCl. The rate of monomer-isomerization polymerization of 5Ph2P with TiCl₃–(C₂H₅)₃Al catalyst was influenced by both the Al/Ti molar ratio and the addition of nickel acetylacetonate [Ni(acac)₂], and the maximum rate was observed at Al/Ti = 2.0 and Ni/Ti = 0.4 in molar ratios.     

Inhibitory effects of 3,3',4,5'-tetrahydroxystilbene and 3,3',4,5'-tetrahydroxybibenzyl, the constituents of Cassia garrettiana on antigen-induced histamine release in vitro.

3,3',4,5'-Tetrahydroxystilbene (I) and 3,3',4,5'-tetrahydroxybibenzyl (II), isolated from the heartwood of Cassia garrettiana Craib (Leguminosae), showed inhibitory effects on antigen-induced histamine release from rat peritoneal mast cells in vitro. The inhibitory effect of I (IC50 = 30.2 microM) was much stronger than that of II (greater than 100 microM). Compound II, as well as I (IC50 = 7.3 microM) reported previously, also inhibited the histamine release from human peripheral basophils induced by anti-immunoglobulin E (IgE) in vitro, and its IC50-value was 68.0 microM. These results suggest that the trans-olefin structure in the molecule may be necessary for I to have an inhibitory effect on histamine release. Considering that disodium cromoglycate did not show any significant inhibitory effect on anti-IgE-induced histamine release from human basophils, the strong inhibitory effects of I in both tests are of considerable interest.     

The confirmation of the formation of clathrate-like hydrates of poly(tetrabutylammonium ethenesulfonate) and of poly(tetraisopentylammonium ethenesulfonate)

A thermal method using differential scanning calorimeter has been applied to aqueous solutions of a series of poly(tetraalkylammonium ethenesulfonates) (R₄NPES). It was found that only the salts withR=n-C₄H₉ andR=i-C₅H₁₁ could form stable hydrates having large hydration numbers. The melting point and hydration numbers of these two hydrates were 12.0°C and 30±1 for the (n-C₄H₉)₄NPES hydrate and 16.0°C and 53±2 for the (i-C₅H₁₁)₄NPES hydrate, respectively. It was concluded that these hydrates were clathrate-like essentially similar to such hydrates as (n-C₄H₉)₄NF·30H₂O and (i-C₅H₁₁)₄NF·40H₂O.     

Shipboard analysis of picomolar levels of manganese in seawater by chelating resin concentration and chemiluminescence detection

A new shipboard analytical method for determining picomolar levels of manganese in seawater has been developed. The method is based on a combination of chelating resin column extraction and improved chemiluminescence (CL) detection in a closed flow system. In this method, manganese in sample solution is selectively collected on newly-developed iminodiacetate-immobilized chelating resin, and then eluted with acidic solution containing hydrogen peroxide. The resulting eluent is mixed with luminol solution and aqueous ammonia after removal of iron ions by a chelating resin column, and then the mixture is introduced into the CL cell. The manganese concentration is obtained from the CL intensity. The detection limit (3SD) of manganese is 5 pmol L^–1 from 9 mL of seawater sample. The method was applied to seawater samples collected at the Okinawa Trough.     

Rationale for the acidity of Meldrum's acid. Consistent relation of C-H acidities to the properties of localized reactive orbital

Detailed investigation on the origin of the acidity of the alpha-protons of a set of the carbonyl molecules was carried out on the basis of properties of the localized molecular orbital. An anomalously high acidity of Meldrum's acid, as compared with those of dimedone and dimethyl malonate, is one of the well-known but unresolved issues. The well-localized sigma orbitals of the C-H bonds at the alpha-position of the carbonyl groups can be obtained with the reactive hybrid orbital (RHO) theory. We found that the energy levels of the unoccupied RHOs of the C-H moiety of Meldrum's acid and other carbonyl compounds showed a good linear correlation with the experimental deprotonation energies. This is probably because the deprotonation reaction to form the proposed naked anions in a polar solvent is a highly endothermic process, in which the thermodynamic energy differences between the neutral molecules and the corresponding anions approximately coincide with the activation energies. We also investigated the effect of the conformational change upon deprotonation on the electron-accepting energy level of the relevant C-H bonds of cyclic/acyclic and monocarbonyl/dicarbonyl compounds. A conformational change occurs in the cases of cyclic six-membered compounds, but its influence on the reactivity of the C-H bond is small. The acidity of dicarbonyl compounds, including Meldrum's acid, showed a good correlation with the deviations from the perpendicular position of the dihedral angles of the relevant C-H bond with respect to the adjacent carbonyl C=O bond. This angle parameter can be related to the magnitude of the in-phase orbital interaction between the sigma(CH) and pi(C)(=)(O) orbitals, which facilitate electron acceptance. These results indicated that the acidity of the alpha-proton of carbonyl compounds can be represented in terms of the electron-accepting orbital levels of the unoccupied RHO of the C-H moiety. All the linear relationships found in the present work strongly suggested that the acidity of Meldrum's acid, which is conventionally regarded as an anomaly, is consistent with those of the other carbonyl compounds.     

Absorption and excretion of suprofen in both sexes of rats, guinea pigs, and rabbits

DL-2-(4-2-Thienylcarbonyl)phenyl)propionic acid (suprofen) was rapidly absorbed in both sexes of rats, guinea pigs, and rabbits after oral administration. Blood levels after a single dose of 2 mg/kg 3H-suprofen in all the animals reached maxima within 15 min, and elimination of the 3H from blood was rapid; the radioactivity was mostly excreted in the urine and feces within 24 h after dosing.     

Double bond isomerization of 5-vinylbicyclo[2.2.1]hept-2-ene to 5-ethylidenebicyclo[2.2.1]hept-2-ene over alkaline earth oxides

All the alkaline earth oxides exhibit activities for double, bond isomerization of 5-vinylbicyclo[2.2.1]hept-2-ene (VBH) to 5-ethylidenebicyclo[2.2.1]hept-2-ene (EBH) at a reaction temperature of 273 K. The order of the activity on the basis of unit weight of catalyst was CaO>MgO>SrO>BaO when compared under optimum pretreatment conditions. The E/Z ratio in the products is determined by the reaction temperature regardless of the type of catalyst; the ratios were 82/18 and 88/12 for the reaction temperatures of 323 and 273 K, respectively.