Multi-stage mixer-settler planet centrifuge. Preliminary studies on partition of macromolecules with organic-aqueous and aqueous-aqueous two-phase solvent systems

A rotary-seal-free planetary centrifuge holds a separation column which consists of multiple partition units (ca. 200) connected in series with transfer tubes. In the cavity of each partition unit the transfer tube extends to form a mixer which vibrates to stir the contents under an oscillating force field generated by the planetary motion of the centrifuge. Consequently, solutes locally introduced at the inlet of the column are subjected to an efficient partition process in each partition unit and separated according to their partition coefficients. The mixer tube equipped with a flexible silicone rubber joint was found to produce excellent results for partition with viscous polymer phase systems. The capability of the method was demonstrated on separation of cytochrome c and lysozyme using a PEG-aqueous dibasic potassium phosphate-aqueous two-phase solvent system.     

Efficient preparation of 2-azulenylboronate and Miyaura-Suzuki cross-coupling reaction with aryl bromides for easy access to poly(2-azulenyl)benzenes

This paper describes an efficient preparation of 2-azulenylboronate (6) starting from 2-iodoazulene by halogen-metal exchange reaction using n-BuLi and subsequent quenching with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. The boronate 6 has been found to undergo Pd-catalyzed Miyaura-Suzuki cross-coupling reaction with a range of aryl bromides including aromatic poly bromides utilizing Pd₂(dba)₃-P(t-Bu)₃ as a catalyst and establishes a strategy to produce novel poly(2-azulenyl)benzenes, some of which are found to be insoluble in common organic solvents, however. The redox behavior of 2-arylazulenes and poly(2-azulenyl)benzenes was examined by cyclic voltammetry (CV) and compared with those of 6-azulenylbenzene derivatives reported previously.     

Hydrophilic polymer-immobilized lipoamides-iron(II) system as a new reducing catalyst for the reduction of O-benzylhydroxylamine by sodium borohydride

Based on a redox function of 1,2-dithiolane ? 1,3-dithiol, lipoamide immobilized on hydrophilic polymers such as polyacrylamide, polyethyleneimine, and chitosan was found to work as polymeric reducing catalysts for the reduction of O-benzylhydroxylamine to benzyl alcohol and ammonia with sodium borohydride in the presence of ferrous ion. These polymers were easily separable and maintained high reactivities even after repeated uses.     

Photochemical dimerization of p-benzoquinone methyl derivatives in crystals

Photochemical dimerization of p-benzoquinone and its methyl derivatives in crystals is discussed assuming that the reactivity is parallel with the stabilization energy of the transient complex. The calculation is carried out by taking both the terms of electronic structure of the monomer molecule and the intermolecular arrangement in the monomer crystal into consideration. Concerning the ability of photodimerization, the result obtained is qualitatively satisfactory. However, such an agreement with experiment cannot be obtained if either the electronic term or the geometrical term is ignored.

---

Zusammenfassung Die photochemische Dimerisierung von p-Benzochinon und seines Methylderivates im Kristallzustand wird diskutiert; dabei wird angenommen, daß die Reaktivität parallel zur Stabilisierungsenergie des Übergangskomplexes ist. Die Berechnung wird so durchgeführt, daß sowohl die Elektronenstruktur des monomeren Moleküls als auch die Lage der Moleküle im Kristall des Monomeren berücksichtigt wird. Die Ergebnisse bezüglich der Fähigkeit zur Photodimerisierung sind qualitativ zufriedenstellend. Eine derartige Übereinstimmung mit dem Experiment kann jedoch nicht erhalten werden, wenn entweder der elektronische Beitrag oder der geometrische Beitrag vernachlässigt werden.

---

Résumé La dimérisation photochimique de la p-benzoquinone et de ses dérivés méthylés dans les cristaux est discutée en supposant que la réactivité évolue parallèlement à l'énergie de stabilisation du complexe de transition. Le calcul est effectué en tenant compte de la structure électronique du monomère et de l'arrangement intermoléculaire dans le cristal du monomère. Le résultat obtenu est satisfaisant qualitativement en ce qui concerne la facilité de photodimérisation. Cependant, un tel accord avec l'expérience ne pourrait être obtenu si l'un des deux termes électronique ou géométrique était négligé.

     

Synthesis of dl-coriolin

The total synthesis of dl-coriolin has been achieved in a stereoselective way. The key tricyclic intermediate was synthesized from dicyclopentadiene through a route which involved an S_N2 reaction at a neopentylic position.     

Sterilization of Bacillus spores by converted X rays

Relative sensitivities of endospores of Bacillus pumilus E601, B. subtilis IAM1069, B. megaterium S31 and B. brevis S5 to gamma rays, converted X rays (bremsstrahlung) and electron beams were examined in order to estimate the conditions in which converted X rays kill Bacillus spores. The radiation sensitivities to gamma rays and electron beams of each strain dried on glass fiber filter without additives were found to be almost equivalent, and D values were obtained as follows: 1.5–1.6 kGy for B. pumilus, 1.4–1.5 kGy for B. subtilis, 1.9–2.0 kGy for B. megaterium and 1.6–2.0 kGy for B. brevis. The radiation sensitivities of endospores of each strain to electron beams were slightly lower than those to gamma rays in the dry condition with additives of 2% peptone + 1 % glycerin on glass fiber filters. The increase of radiation resistance in the presence of additives was also observed with X rays, and it was on an intermediate level between those with gamma rays and electron beams. In the dry condition using cellulose filter paper, only the radiation resistances of B. megaterium and B. brevis in the presence of additives B. megaterium and B. brevis in the presence of additives were increased.     

Preparation and structure of (R)-(−)- and (S)-(+)-2,2′-(2,2-dimethyl-2-silapropane-1,3-diyl)-1,1′binaphthalene

The title axially dissymmetric organosilicon compound is obtainable in optically pure from by synthesis of the racemate followed by resolution with a chiral poly(triphenylmethyl methacrylate) column. The structure has been established by spectroscopic and single crystal X-ray diffraction methods.     

Separation of radioactive metabolites in cultured tea cells fed with [14C]phenylalanine using high-speed counter-current chromatography

Separation of radioactive metabolites in cultured tea cells fed with [14C]phenylalanine was conducted using high-speed counter-current chromatography. Among seven components obtained our studies focused two metabolites, i.e. (-)-epicatechin and D,L-catechin. The specific radioactivity of (-)-epicatechin was 212.01 KBq/mg, amounting to 8.5% of the total radioactivity of ethyl acetate extract while that of D,L-catechin was 1.0006 MBq/mg or 5.4% of the total.     

Chemical synthesis of 23 kDa glycoprotein by repetitive segment condensation: a synthesis of MUC2 basal motif carrying multiple O-GalNAc moieties

Peptide thioester corresponding to a MUC2 tandem repeat unit, which retains seven GalNAc moieties, was prepared by the Fmoc method followed by the low TfOH treatment to remove benzyl groups at the carbohydrate portions. The glycosylated peptide thioester was then consecutively joined by the activation of a thioester group by silver ions to obtain a MUC2 tandem repeat model composed of 141 amino acids with 42 GalNAc moieties.