The crystal structure of penta-O-acetyl-beta-D-galactopyranose was determined with Mo K(alpha) radiation at 150 K to R = 0.029. The space group is P2(1)2(1)2(1), and the unit cell dimensions are, a = 8.348, b = 9.021 and c = 25.418 A.
1,2,3,4,6-Penta-O-acetyl-beta-D-galactopyranose was transformed into phenyl 2,3,4,6-tetra-O-benzyl-1-thio-beta-D-galactopyranoside (5) and 4-methoxyphenyl 2,3,6-tri-O-benzoyl-beta-D-galactopyranoside (8) in 73% (two steps) and 58% (three steps) yield, respectively. Glycosylation of the acceptor 8 with donor 5 using N-iodosuccinimide-trimethylsilyl trifluoromethanesulfonate as promoter furnished the galabioside 9 (8.8 g)
Comparative X-ray diffraction analysis of 5,6,7,9-tetra-O-acetyl-4,8-anhydro-1,3-dideoxy-D-glycero-L-gluco-nonulose (1) and a structurally related analog, 1,2,3,4,6-penta-O-acetyl-beta-D-galactopyranose (2), are reported. Both crystals have one molecule in the unit cell and the pyranose rings in both exist in the 4C1 conformation.
Zeolite-catalyzed glycosylation of long-chain alcohols, using the inexpensive and readily available peracetylated beta-D-gluco- and galactopyranoses as glycosyl donors under solvent free conditions, has been explored for the first time. Among the various forms (H-, Na-, Fe- and Zn) of beta
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