DMPM (3,4-dimethoxybenzyl) protecting group for hydroxy function more readily removable than MPM (P-methoxybenzyl) protecting group by DDQ oxidation

The DMPM (3,4-dimethoxybenzyl) protection for hydroxy function was deprotected more readily than the MPM (p-methoxybenzyl) protection by DDQ oxidation under neutral conditions, and applied to the synthesis of some synthons to macrolide and polyether antibiotics.     

Polymerisation von Propylen mit Tetrabenzylzirkonium

Ohne Zusammenfassung     

The isolation and structure of tricyclosolidagolactone,a new diterpene from solidago altissima l.

Tricyclosolidagolactone has been isolated from the leaves of $\text{Solidago altissima}$ L., and its structure also been elucidated on the basis of its spectral data coupled with an X-ray crystallographic analysis of the corresponding trihydroxy compound produced on LiAlH₄ reduction.     

Synthesis and evaluation of 5-thio-L-fucose-containing oligosaccharide

5-Thio-L-fucose-containing trisaccharide H-type II was synthesized. The 3',4'-O-isopropylidene-2-azido-2-deoxylactoside derivative, which was prepared from lactose by azidonitration of lactal, was used as a starting material. By regio- and stereoselective 5-thio-L-fucosylation of the 6,6'-dibenzoate 5 with 5-thiofucosyl trichloroacetimidate 6 and subsequent deprotection gave the 5-thio-L-fucose-containing H-type II 1. Conformational analysis of the 5-thio-L-fucose-containing H-type II and the native H-type II was carried out through NOESY experiments. The observed NOE values between N-acetylglucosamine and galactose, and galactose and fucose were same for these two trisaccharides. However, NOE values between fucose and N-acetylglucosamine were significantly different. Binding of the 5-thio-L-fucose-containing H-type II to lectins and antibodies were in some case stronger and in some case weaker than those of the native trisaccharide.     

The rise process of the electric birefringence of poly-γ-benzyl-l-glutamate at high fields

Summary The rise process, steady-state and decay process of the birefringence of poly--benzyl-l-glutamate solutions under the action of a rectangular pulse have been studied at 25 °C over a wide range of field strength of 1.5×10³ to 3×10⁴V/cm. The solvent used was a dichloroethane-dimethylformamide mixture of the volume ratio 991. From the decay process the average relaxation time extrapolated to zero concentration and the corresponding rotational diffusion constant were determined. The apparent dipole moment and the optical anisotropy factor were obtained from the field strength dependence of steady-state birefringence. The rise process was analyzed according to our theory which holds for arbitrary high field strength in the initial stage. The n(t)/t versus t curves for various field strengths were found to be linear in the initial stage and pass through the origin. Thus, it was concluded that the electrical orientation of poly--benzyl-l-glutamate in solution is due primarily to the permanent dipole moment. Furthermore, the value of the apparent permanent dipole moment obtained from the rise process was compared with that obtained from the steadystate birefringence.

---

Zusammenfassung Der Einschaltvorgang, der stationäre Zustand und das Abklingen der Doppelbrechung bei Poly--benzyl-l-glutamat-Lösungen mit einem elektrischen Impuls von rechteckiger Form werden bei 25 °C über einem großen Feldstärkebereich von 1.5×10³–3×10⁴V/cm untersucht. Als Lösungsmittel wird die Dichloräthan/Dimethylformamid-Mischung im Volumenverhältnis 991 verwendet. Aus dem Abklingvorgang werden die zur Konzentration 0 extrapolierte mittlere Relaxationszeit und die entsprechende Rotationsdiffusionskonstante bestimmt. Das scheinbare permanente Dipolmoment und der optische Anisotropiefaktor werden aus der Feldstärkeabhängigkeit der stationären Doppelbrechung ermittelt. Der Einschaltvorgang wird nach unserer Theorie, die für beliebige hohe Feldstärken im Anfangsverlauf gültig ist, analysiert. Die n(t)/t gegen t-Kurven für verschiedene Feldstärken sind geradlinig im Anfangsverlauf und laufen durch den Ursprung. Hieraus zeigt sich, daß die elektrische Orientierung von Poly--benzyl-l-glutamat in Lösungen hauptsächlich durch das permanente Dipolmoment bedingt ist. Überdies wird der aus dem Einschaltvorgang gewonnene Wert des scheinbaren permanenten Dipolmomentes mit dem aus der stationären Doppelbrechung ermittelten Wert verglichen.

---

---

With 7 figures     

Poisson Boundary of the Dual of SU q (n)

We prove that for any non-trivial product-type action α of SU_q(n) (0<q<1) on an ITPFI factor N, the relative commutant is isomorphic to the algebra L^∞() of bounded measurable functions on the quantum flag manifold . This is equivalent to the computation of the Poisson boundary of the dual discrete quantum group . The proof relies on a connection between the Poisson integral and the Berezin transform. Our main technical result says that a sequence of Berezin transforms defined by a random walk on the dominant weights of SU(n) converges to the identity on the quantum flag manifold. Supported by JSPS. Partially supported by the Norwegian Research Council. Supported by the SUP-program of the Norwegian Research Council.