Alternating copolymerization of polar vinyl monomers in the presence of zinc chloride. I. Propagation and initiation of the copolymerization of acrylonitrile with styrene copolymer

Copolymerization of acrylonitrile with styrene spontaneously occurred on addition of zinc chloride without addition of any other radical initiator. The composition of the copolymer approached that of strictly alternating copolymer as zinc chloride added to the copolymerization system increased. The significance of the apparent monomer reactivity ratios of this copolymerization system was studied from a kinetic point of view, and it was shown that the monomer sequence distribution is indicated by the apparent monomer reactivity ratios. Further, equations which represent the relation between the apparent monomer reactivity ratios and Q,e values at a given salt concentration were derived. These equations reasonably accounted for the decrease of the apparent monomer reactivity ratios of the copolymerization of acrylonitrile with styrene in the presence of zinc chloride and the behavior of the other acrylonitrile copolymerization systems in the presence of zinc chloride. The initiation step of the spontaneous radical copolymerization of acrylonitrile with styrene in the presence of zinc chloride was explained by a cross-initiation mechanism.     

Oxidation products of 2-arylphenanthro-[9,10-d]imidazoles—II : Structure and photochromism of oxidation products of 2-(4-methoxyphenyl)-phenanthro-[9,10-d]imidazole

By ferricyanide oxidation of 2-(4-methoxyphenyl)phenanthro[9,10-d]imidazole, three new photochromic compounds were obtained. These were 4-ethoxy-4H-, 4-methoxy-4H- and 2-methoxy-2H-phenanthro[9,10-d]imidazoles. These compounds gave the 2-(4-methoxyphenyl)-phenanthro[9,10-d]imidazolyl radical and acetaldehyde or formaldehyde by light irradiation. The imidazolyl radical dimerized gradually in the dark and the dimer dissociated to the imidazolyl radical on heating.     

Polymer-supported bases. IX. Synthesis and catalytic activity of polymer-bound 4-(1-pyrrolidino)pyridine moieties

Polystyrene-bound 4-(1-pyrrolidino)pyridine moieties were prepared by the reaction of chloromethylated polystyrene resins with pyrrolidinopyridine derivatives containing hydroxyl groups. The supported amines were effective catalysts for acylations of tert-alcohols or enols, acylrearrangements, and diester synthesis from epoxides and anhydrides. Some of the low ring-substituted (8–15%) catalysts exhibited high activity comparable to that of 4-(N,N-dimethylamino)pyridine, though the activity was a little lower than that of 4-(1-pyrrolidino)pyridine. The recovered catalysts can be re-used, except for acyl rearrangements, without significant decrease in activity.     

Preparation of New Photosensitive ZrO2 Gel Films Using Hydroxyl-Substituted Aromatic Ketones as Chemical Modification Reagents and their Patterning

ZrO₂ gel films were prepared from zirconium tetra-n-butoxide chemically modified with one of hydroxyl-substituted aromatic ketones and 1′-hydroxy-2′-acetonaphthone, by the sol-gel method. The obtained gel film showed an absorption band, characteristic of the π-π* transition of chelate ring, at around 410 nm. The band was shifted to longer wavelength region than those for the gel films using β-diketones. The reason is thought that the hydroxyl-substituted aromatic ketone has π-electron system to form the condensed chelate ring. The absorption band associated with the chelate ring gradually decreased in intensity with UV-irradiation using a high pressure mercury lamp. This indicates that the chelate ring dissociates by the UV-irradiation and that the gel film exhibits photosensitivity. Utilizing the photosensitivity, fine patterns (about 1 μm) could be fabricated by UV-irradiation through a mask and leaching.     

Method for optical resolution of racemic homochlorcyclizine and comparison of optical isomers in antihistamine activity and pharmacokinetics.

A method was developed for semi-preparative scale enantioseparation of racemic homochlorcyclizine (HCZ) by high performance liquid chromatography (HPLC) on Chiralcel OD column. The best resolution was achieved using an eluent composed of n-hexane plus 0.2 M isopropylamine. By this method, about 5.0 mg of racemic HCZ could be resolved completely in one run. The optical purity of the enantiomers were both greater than 99.9%. The studies of antihistamine activity on guinea pig ileum demonstrated that l-HCZ is significantly more potent than d- and racemic HCZ. The pharmacokinetics of d- and l-HCZ after oral administration to rats also differed. The successful resolution of racemic HCZ permits comparison of the pharmacokinetics and antihistamine activity of the enantiomers.     

Profiling analysis of oligosaccharides in antibody pharmaceuticals by capillary electrophoresis

Carbohydrate chains in glycoprotein pharmaceuticals have important roles for the expression of their biological activities. Therefore, development of an assessment method for the carbohydrate chains is an important parameter for quality control of glycoprotein pharmaceuticals such as newly developed therapeutic antibodies. In this report, we applied capillary electrophoresis with laser-induced fluorescence detection to the analysis of carbohydrate chains after releasing with glycoamidase followed by derivatization with 3-aminobenzoic acid. We found that four major oligosaccharides present in antibody pharmaceuticals were successfully separated with good resolution. The present method showed good precision in both migration times and relative peak areas, and gave comparable accuracy with that using a derivatization method with 8-aminopyrene-1,3,6-trisulfonate.     

Y-931, a novel atypical antipsychotic drug,is less sensitive to oxidative phenomena

The oxidation behavior of Y-931, a potent atypical antipsychotic drug, was compared with that of clozapine and olanzapine. In two enzymatic systems (horseradish peroxidase (HRP)/glutathione (GSH) and HRP/H(2)O(2)/GSH) which generate thiyl radicals, clozapine markedly strengthened the electron paramagnetic resonance (EPR) signal for the radical. Olanzapine, Y-931 and the major metabolites (compounds 1-3) had no or minimal effect on the intensity of this signal. In addition, the redox potential values for the three derivatives were in accord with the EPR spin trapping results. In toxicological experiments in human leukocytes, a concentration-dependent toxicity was observed when neutrophils were incubated with clozapine (1-10 micromol/l) and H(2)O(2) (1 mmol/l). However, Y-931 and olanzapine did not show remarkable toxicity under the conditions.