Galactopyranose spectroscopy

From the rearrangement of tetra-O-acetyl-2-hydroxy-D-galactal in boiling acetic acid it was possible to isolate l,2,4,6-tetra-0-acetyl-2,3-dide-h.ydro-3-deoxy-a-jy-threo-hexose (32) (58%) and a small amount of 1,2,3,4,6-penta-O-acetyl-jS-D-galactopyranose. In the reaction mixture the presence of some a-pentaacetate was demonstrated chromatographically but NMR spectroscopy indicated no resonances corresponding to the / anomer of compound 32. These spectral measurements indicate that compound 32 constituted 80% of the mixture of products. 

The statistical distribution of the conformational orientations of the hydroxymethyl and esterified hydroxy-groups in glucopyranoses and galactopyranoses in the Ci conformation were shown to be g/g (60%) and g/t (40%) for the former, and gjt (58%), tig (34%), and g/g (8%) for the latter. The reasons for the unfavourable tjg conformation for glucopyranose and gjg conformation for galactopyranose were discussed in relation to steric and electronic interactions. Two-dimensional J spectroscopy has been applied to the 270 MHz spectra of (1) and 2) The influence of 0-alkyl groups on the chemical shift of the... 

A study of the conformations of amylose and cellulose oligomers using vibrational spectroscopies has been reported. At the same conference, the use of FTIR (near, mid and far IR), and EXAFS, for spectroscopic characterization of mono- and disaccharides and coordination transition metal complexes was described. IR has been applied to characterize l,2 3,4-di-0-isopropylidene-6-0-triphenylstannylmethyl-a-D-galactopyranose. ... 

The n.m.r. spectra of sugars of the galactopyranose series have been the subject of a review in Japanese. A study by C n.m.r. spectroscopy of some 2,3 4>6-tetra-0-acetyl-/l-D-galaotopyrano8-... 

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