The nuclear magnetic resonance spectra for N-(tetra-0-acetyl-a-D-glucopyranosyl)-pyridinium and 4-methylpyridinium bromides and N-(tri-0-acetyl-2-deoxy-2-iodo-a-D-mannopyranosyl)-pyridinium perchlorate (V) require these compounds to exist in the 1C-conformation wherein the pyridinium group is in equatorial orientation. T h e highly strained condition of V was evidenced b y its high reactivity as compared to the 8-D-gluco diastereoisomer (IV). I t is suggested that the instability of the Cl-conformation is partly attributable to the reverse of the ano~neric effect, and the probable importance of this phenomenon is discussed. The optical rotatory dispersion properties of these and a number of other pyridinium glycosides are presented.

D-Glucal triacetate reacted with iodoniurn and brornoniurn di-sym-collidine perchlorate complexes in the presence of 2,3,4,6-tetra-O-acetyl-j3-~-glucopyranose to yield, after deacetylation, crystalline P-D-glucopyranosyl 2-deoxy-2-halogeno-a-D-mannopyranosides. The halogen was hydrogenolyzed catalytically to yield 8-D-glucopyranosyl 2-deoxy-a-D-arabino-hexopyranoside (2-deoxy-neotrehalose) isolated as the crystalline heptaacetate. A correction of the literature is made regarding the preparation of 142,3,4,6-tetra-0-acetyl-a-D-glucopyranose".

The classical metallocenes, ferrocene and ruthenocene, dissolve readily in neat ethyl 2-cyanoacrylate (CA) monomer. The electronic spectra of the resulting solutions display a near-ultraviolet absorption band assigned as a charge-transfer-to-solvent (metallocene → CA) transition. Irradiation into this band causes the one-electron oxidation of the metallocene to the corresponding metallocenium cation accompanied by reduction of CA to its radical anion. Addition of the latter species to CA initiates the anionic polymerization of the electrophilic monomer. The progress of photoinitiated polymerization was monitored in real time by attenuated total reflectance infrared spectroscopy.

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Verschiedene Darstellungswege von Peroxiden aus Ketonen werden beschrieben.