New Synthesis of 1-D-O-(2-Amino-2-deoxy-D-gluco- and -galactopyranosyl)-chiro-inositols

Abstract

New and highly effective procedures for the preparation of d-chiro-inositol derivatives, essentially based on selective protection of the vicinal diequatorial diol systems present in this molecule, are reported. This selective protection affords C 2 -symmetric diaxial diols such as 4 and 5, glycosylation of

A Study on the Influence of the Structure of the Glycosyl Acceptors on the Stereochemistry of the Glycosylation Reactions with 2‐Azido‐2‐Deoxy‐Hexopyranosyl Trichloroacetimidates

“…Table 2 summarizes the results in comparison with those previously reported by us for the D ‐ chiro series 11g. Glycosylations with the per‐O‐benzylated D ‐glucotrichloroacetimidate 13 , which had shown poor stereoselectivity in the D ‐ chiro series, showed no stereoselectivity in the L ‐ chiro series and compounds 25 α and 25 β and 32 α and 32 β were isolated in similar proportions.…”

“…Compound 9 , the enantiomer of 5 , was synthesized from D ‐ myo ‐inositol12 and compounds 10 and 11 , the enantiomers of 6 and 7 , respectively, from L ‐quebrachitol following the protocol described for the preparation of 6 and 7 from D ‐ chiro ‐inositol (Figure 3). 11g…”

“…The stereoselectivity of these glycosylations also seemed to be somehow dependent on the structure of the acceptor. In the case of the D ‐ chiro ‐inositol derivatives, where a series of pseudodisaccharides were required having the α1→1 glycosidic linkage, the reaction of acceptors 5 , 6 and 7 with 2‐azido‐2‐deoxy‐ D ‐glucopyranosyl trichloroacetimidates, afforded anomeric mixtures containing a considerable amount of the β‐anomers 11c,g,h. By contrast, the α1→2 glycosidic linkage in the same D ‐ chiro series and the α1→3 glycosidic linkage in the L ‐ chiro series11i as well as the α1→6 glycosidic linkage in the D ‐ myo series11b,e were formed with fair to good stereoselectivity under similar experimental conditions.…”

Synthesis of galactosaminyl d-chiro-inositols

“…While several differentially protected 8 chiro-inositols have been synthesized, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] we sought a general strategy for the syntheses of a complete set of penta-O-benzyl-D D-chiro-inositols, each with a different unprotected hydroxyl group for glycosylation. Since chiro-inositol has a C 2 axis of symmetry, the set consists of only three different penta-O-benzyl-chiro-inositols: 8, 9, and 10.…”

“…The a anomers of the unacetylated disaccharides have been previously prepared by other methods. 20,21,24 …”