Silyl-enolization-asymmetric Claisen rearrangement of 2-allyloxyindolin-3-one: enantioselective total synthesis of 3a-hydroxypyrrolo[2,3-b]indoline alkaloid alline

Asymmetric Claisen rearrangement triggered by silyl-enolization of 2-(1′-nonel-3′-yloxy)indolin-3-ones was performed in order to prepare 3-(2′-nonenyl)-3-hydroxyindolin-2-ones. Total synthesis of 3-hydroxypyrrolo[2,3-b]indoline alkaloid, (+)-alline was achieved by transformation of the allylic moiety of 3-(2′-nonenyl)-3-hydroxyindolin-2-one to amine followed by reductive cyclization.     

Differential interactions of cyclodextrins with hydrophobic derivatives of sepharose CL-4B

The partition coefficients K_av between the solution phase and octyl- and phenyl-sepharose CL-4B were determined for three cyclodextrins (CDs), -CD, -CD and -CD in various aqueous solutions, as a measure of their interactions with the two hydrophobic ligands. K_av of the CDs increased in the order of -CD<-CD<-CD for octyl-sepharose CL-4B and -CD<-CD<-CD for phenyl-sepharose CL-4B. In all cases, K_av increased by increasing NaCl concentration in the aqueous solution phase and also by lowering temperature, but in the presence of NaBr and NaSCN, both chaotropic salts, K_av decreased markedly. The spontaneity of the transfer of the CDs from the aqueous solution phases to the gel phases was due to the enthalpy decrease. It was shown that discrete separation of the three CDs can be achieved by the hydrophobic chromatography on a short column (1×25cm) of octyl-sepharose CL-4B by adjusting the NaCl concentration and temperature.     

Quantum dot-based immunosensor for the detection of prostate-specific antigen using fluorescence microscopy

A sensitive optical method based on quantum dot (QD) technology is demonstrated for the detection of an important cancer marker, total prostate-specific antigen (TPSA) on a disposable carbon substrate surface. Immuno-recognition was carried out on a carbon substrate using a sandwich assay approach, where the primary antibody (Ab)-protein A complex covalently bound to the substrate surface, was allowed to capture TPSA. After the recognition event, the substrate was exposed to the biotinylated secondary Abs. After incubation with the QD streptavidin conjugates, QDs were captured on the substrate surface by the strong biotin-streptavidin affinity. Fluorescence imaging of the substrate surface illuminated the QDs, and provided a very sensitive tool for the detection of TPSA in undiluted human serum samples with a detection limit of 0.25 ng/mL. The potential of this method for application as a simple and efficient diagnostic strategy for immunoassays is discussed.     

Initiation and propagation in γ-radiation-induced polymerization of ethylene

The initiation and propagation reaction in γ-ray-induced polymerization of ethylene was studied by the two-stage irradiation method, i.e., a first stage in which initiation and propagation occur at a high dose rate, and a second stage where only the growth of polymer radical occurs. The rate of initiation is calculated from the amount of polymerized monomer and the degree of polymerization as the rate of increase in the number of polymer chains. The initiation rate is shown to be proportional to the ethylene density in the reactor and dose rate. G_R of radical formation is found to be about 1.6 at 30°C. at a dose rate of 2.5 × 10⁴ rad/hr. and is almost independent of ethylene density but decreases slightly with increasing irradiation dose rate. The lifetime of the growing polymer chain radical is shown to be long at normal temperature. The absolute propagation rate is proportional to the square of ethylene fugacity and depends on dose rate to some extent. For chain growth, irradiation of low dose rate is necessary. The apparent activation energy for the propagation reaction is ?9 kcal./mole.     

PRESUMED PHOTORECEPTOR PROTEIN AND ULTRASTRUCI'URE OF THE PHOTORECEPTOR ORGANELLE IN THE CILIATED PROTOZOAN, Blepharisma

Abstract-The red pigment granule of Belpharisma japonicum is believed to be a photoreceptor organelle mediating photodispersal. Freeze-fracture and thin section electron microscopy revealed that the pigment granules contained a honeycomb-like structure constructed of folded membranes. In the fracture face of the honeycomb-like structure, small membrane particles were observed, which might correspond to pigment—protein complexes. The pigment granules were isolated and detergent-solubilized. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the pigment granules mainly contained a 200 kDa membrane protein. The complex of red pigment and 200 kDa protein was isolated by gel-filtration chromatography of the detergent-solubilized components, and the protein was subjected to SDS-PAGE and amino acid analysis. The 200 kDa protein could not be dissociated into subunits by 2-mercaptoethanol, indicating that the protein is composed of a single polypeptide chain. Hydrophobic amino acids contained in the 200 kDa protein were not dominant, suggesting that only partial domains may extend across the membrane of the honeycomb-like structure.     

Molecular weight determination of hypromellose phthalate (HPMCP) using size exclusion chromatography with a multi-angle laser light scattering detector

The molecular weight of hypromellose phthalate (HPMCP), a polymer used for enteric coating, was determined using size exclusion chromatography with a multi-angle laser light scattering detector. The values of weight-average molecular weight (Mw) of commercially available grades (HP-55, HP-55S, and HP-50) were 45600, 60200, and 37900, respectively. Their inter-day precisions expressed in terms of the coefficient of variation were less than 3%. A correlation curve between Mw and solution viscosity was prepared so that Mw could be easily estimated from the solution viscosity measured by the compendial method.     

Two-stage irradiation study on propagation and termination in the γ-radiation-induced polymerization of ethylene in liquid carbon dioxide

The propagation and termination reaction in the γ-radiation-induced ethylene polymerization in liquid carbon dioxide were investigated by a two-stage irradiation. After irradiation at high dose rate, the polymerization occured at a considerable rate under the extremely low dose rate without initiation. The absolute propagation rate was determined in the second stage to be proportional to the square of ethylene fugacity and depended slightly on dose rate. The apparent activation energy for the propagation reaction is ?9 kcal./mole. From these observations which are the same as those in bulk polymerization, it is concluded that carbon dioxide acts as a diluent of ethylene monomer in the propagation reaction. Also, carbon dioxide was shown to be inactive to the growing radicals without irradiation, but oxygen which is produced by the radiolysis of carbon dioxide at high dose terminates the growing radicals with formation of carbonyl in the polymer.     

New quinone sulfates from the crinoids Tropiometra afra macrodiscus and Oxycomanthus japonicus

Quinone pigments in the crinoids were investigated. New quinone sulfates 1 and 3 were isolated from Tropiometra afra macrodiscus and Oxycomanthus japonicus, respectively. The structures 1 and 3 were determined to be 1,6,8-trihydroxy-3-propylanthraquinone-2-carboxylic acid 6-O-sulfate (ptilometric acid 6-O-sulfate) and 2-butanoyl-3,6,8-trihydroxy-1,4-naphtoquinone 6-O-sulfate, respectively, by chemical and spectroscopic analysis. Ptilometric acid 6-O-sulfate (1) showed an antifeedant activity on fish.     

Reaction of 6-phenyl-2-(p-toluenesulfonyl)-3(2H)pyridazinone with grignard reagents

6-Phenyl-2-(p-toluenesulfonyl)-3(2H)pyridazinone (I) reacted with Grignard reagents to give 5-substituted 4,5-dihydro-3(2H)pyridazinones II and two types of dihydropyridazines, III and IV. The ratio of II, III, and IV was sensitively dependent on the reaction conditions. Further, by quenching the reaction mixture with alcohol, the ring-opened product VII was mainly isolated.     

Effect of alcohols on the gamma-radiation-induced polymerization of ethylene

Gamma-radiation-induced polymerization of ethylene in alcohols such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and n-pentyl alcohols was carried out under a pressure of 400 kg./cm.²at 30°C. at a dose rate of 1.4 × 10⁵ rad/hr. in a batch reactor of 100 ml. capacity. The yield and molecular weight of polymer formed in the alcohols (except tert-butyl alcohol) were much lower than those of the bulk polymerization under the same conditions, whereas the addition of tert-butyl alcohol increased the yield and reduced the molecular weight. From the infrared spectra of the polymers and those of the bromination products it was concluded that only primary OH exists in the polymer formed in methyl alcohol and that both primary and secondary OH are in the polymer formed in other primary alcohols. Both secondary and tertiary OH were observed in the polymer when the secondary alcohols were used, and only tertiary OH in the case of tert-butyl alcohol. These polymers were found to contain small amounts of vinylidene unsaturation and methyl group. On the basis of these results the roles of the alcohols in the polymerization are discussed.