Correlation pyranosides

Z = 4 D, = 1.52 R = 0.049 for 1,606 intensities. An error in the atomic coordinates for C-6 prevents display of this molecule. The atomic coordinates for C-l 1 were omitted, and those for H-61 and H-62 appear to be in error. The linkage, orientational angles between the hexenopyranosyl and the pyranoside ring are 0-5 -C-l -0-4-C-4 = +83°, C-l -0-4-C-4-C-5 = —139°. The epoxy ring is equilateral, with C-C = C-0 = 146 pm, and the ring-angles equal to 60 0.3°. The results of this analysis were correlated with those from the n.m.r. spectrum of the compound in solution. 

On the grounds that furanosides anomerise and hydrolyse very much more readily than do the corresponding pyranosides. Bishop eind Cooper assumed that the first step in the glycosidation process is the methanol-ysis of the furanose form of the free sugar, and they visualised, without evidence, a unimolecular process proceeding by way of a stabilised cyclic ion (1). In support of this they observed 5) that for xylose, lyxose and ribose the furanoside formation rates (3,1,12 respectively) correlated with the furanoside contents at equilibrium (see Table 3) and hence, presum-... 

The influence of hydrophobic substituents on the inhibition potency of aryl a- and /3-D-gluco- and a-D-manno-pyranosides was also investigated. A linear correlation was demonstrated between the hyd-rophobicity of the substituent and the inhibiting power of the glycoside for o-, m-, and p-substituted-phenyl /3-D-gIucopyranosides.180,181,333,436... 

Nelson and Johnson (11,12,13) have suggested that there is a correlation in the sign of the 164-177 nm band and the anomeric configuration of methyl pyranosides. Typical of the evidence for that suggestion is that methyl a- and B-D-xylopyranosides show positive and negative bands, respectively near 174 nm other pairs of monosaccharides show a similar correlation (11,12,13). Significantly for the present work, however, they observed an exception to this correlation in the case of glucopyranosldes methyl... 

In the Raman and i.r. spectra of crystalline methyl 3,6-dideoxy-/3-D-ri o-hexo-pyranoside measured at low temperatures, four O-H bands were observed in the O-H stretching region. These were correlated with four distinct hydrogen bonds determined from X-ray data, and deuterium-isotope dilution methods were used to assist the analysis. An interesting study of the far-i.r. spectrum of a pyroelectric sucrose single crystal has been carried out, and the temperature dependence was correlated with polarization of the low-frequency mode (49.5 cm" ) along the binary axis. ... 

Dithiane Route. The route, outlined in Figure Sb fulfills these two requirements. An a-enal-pyranoside IX is correlated synthetically with a dieno-... 

Further applications of a semieittpirical theory of optical activity have been reported. Calculated sodium-D line molar rotations for methyl pyranosides were consistently low, but the general dependence on structure was reproduced.The dominant origin of sodium-D rotation has been correlated with a vacuum-u.v. band near 150 nm, observed in c.d. spectra of polysaccharide films. 

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