Synthesis of 2-azidoethyl α-d-mannopyranoside orthogonally protected and selective deprotections

4 páginas, 1 figura, 2 esquemas.We present the synthesis of a fully orthogonally protected mannosyl glycoside 1 and the corresponding methods for selective deprotections. Mannosyl glycoside 1 contains a functionalized linker at the anomeric position to allow for the attachment of carbohydrate units to scaffolds in order to prepare carbohydrate multivalent systems.We would like to thank FIS (PI030093), for financial supportPeer reviewe

Measurement of hadron and lepton-pair production at 161 GeV<root s<172 GeV at LEP

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Measurement of the B-d(0)-(B)over-bar(d)(0) oscillation frequency RID C-4549-2008 RID C-5719-2008

Time-dependent B-0-(B) over bar(0) mixing is studied using about two million hadronic Z decays registered by L3 in 1994 and 1995. For this study three techniques are used. Tagging of the b-quark charge at decay time is performed by identifying leptons from semileptonic B decays. The flavour of the b quark at production time is determined from the charge of the lepton in the opposite hemisphere or by using a jet-charge technique. The proper time of the B-particle decay is obtained by reconstructing the production and decay vertices or by a measurement of the lepton impact parameter. The combined result for the frequency of B-d(0) meson oscillations is Delta m(d) = 0.444 +/- 0.040 ps(-1)

Measurement of the inclusive charmless semileptonic branching fraction of beauty hadrons and a determination of vertical bar V-ub vertical bar at LEP RID C-4549-2008 RID C-5719-2008

A measurement of the inclusive charmless semileptonic branching fraction of beauty hadrons, b --&gt; X-u l nu, has been performed using almost two million hadronic Z decays collected by the L3 experiment at LEP, yielding the result: Br(b --&gt; X-u l nu) = (3.3 +/- 1.0 +/- 1.7) x 10(-3). The first uncertainty is statistical and the second is systematic. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element V-ub extracted from this measurement is: V-ub = (6.0(-1.0-1.9)(+0.8+1.4) +/- 0.2) x 10(-3), where the uncertainties are statistical, systematic and theoretical, respectively. (C) 1998 Elsevier Science B.V. All rights reserved