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Gas Chromatographic Investigation of the Boron Trifluoride Etherate-Induced Formation and Anomerisation of Glucopyranosides

Boron trifluoride etherate-induced glucosylation of methanol, 1-propanol, 2-propanol, 2-bromoethanol, and 3-bromo-2-(bromomethyl)propan-1-ol, using 1,2,3,4,6-penta-O-acetyl-β-D-glucopyranose as donor, gave the corresponding β-glucopyranosides. The α-glucosides and 1,2,3,4,6-penta-O-acetyl-α-D-glucopyranose were formed as byproducts in varying amounts, according to GLC analysis. The propensity of t

Calculated conformations of sialyl-Lex- and sialyl-Lea-lactones

The minimum energy conformations of the four sterically reasonable SLex and SLea lactones were calculated using the molecular mechanics force-field MM2(91). The tetrasaccharide lactone involving the 3- and 2-position of the Gal moiety was found to be more stable than the 3,4-lactone both for SLex and SLea. © 1994.

Anomeric Effect in Furanosides. Experimental Evidence from Conformationally Restricted Compounds

A series of conformationally restricted 0-, C-, S-, and N-“furanosides” have been synthesized, where the number 3 and 4 carbons are part of a norbornane ring system. All the carbons of the tetrahydrofuran ring are kept in one plane by the rigid norbornane skeleton, permitting only the ring oxygen to move above or below the tetrahydrofuran ring plane. This causes the substituents on carbon 2 to occ

2-(Trimethylsilyl)ethyl Glycosides. Transformation into the Corresponding. 1-O-Acyl Sugars

(Trimethylsilyl)ethyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside and (trimethylsilyl)ethyl 2,3,6-tri-O-acetyl-4-O-(2,3,6-tri-O-acetyl-4-O-[2-acetamido-4,6-di-O-ace tyl-2- deoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D- galactopyranosyl]-beta-D-galactopyranosyl)-beta-D-glucopyranoside have been transformed in high yield into the corresponding 1-O-beta-acyl saccharides by treat

Dual-Band Frequency Selective Surface with Different Polarization Selectivity for Wireless Communication Application

This article proposes a dual-band, frequency- and polarization-selective surface. Multiple resonant modes are introduced using the U-shaped resonator with a ground via to achieve dual-band responses and polarization selectivity. Two symmetrically grounded U-shaped resonators are coupled through electrically coupled apertures in a common ground, resulting in a passband with two transmission zeros p

Contextual shifts and gradable knowledge

Epistemological contextualism states that propositions about knowledge, expressed in sentences like “S knows that P,” are context-sensitive. Schaffer (2005) examines whether one of Lewis’ (1996), Cohen’s (1988) and DeRose’s (1995) influential contextualist accounts is preferable to the others. According to Schaffer, Lewis’ theory of relevant alternatives succeeds as a linguistic basis for contextu

Shifts in the smart research agenda? 100 priority questions to accelerate sustainable energy futures

Energy transitions are at the top of global agendas in response to the growing challenges of climate change and international conflict, with the EU positioning itself as playing a pivotal role in addressing climate risks and sustainability imperatives. European energy transition policies identify ‘smart consumption’ as a key element of these efforts, which have previously been explored from a pred