Mulard L A, Claudemans C P
NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.
Carbohydr Res. 1995 Sep 8;274:209-22. doi: 10.1016/0008-6215(95)00122-a.
The synthesis of methyl O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-D-galactopyranosides specifically deoxygenated at position 2 (31), or 4 (21) of the rhamnopyranosyl residue was accomplished using methyl 3,4,6-tri-O-benzoyl-alpha-D-galactopyranoside (18) as the glycosyl acceptor. Phenyl thionocarbonate activation of the penta-O-benzoylated disaccharide precursor followed by Barton reduction and Zemplén transesterification gave 31, while 21 was obtained via condensation of the deoxygenated monosaccharide donor with 18, and subsequent debenzoylation of the product.
以3,4,6-三-O-苯甲酰基-α-D-吡喃半乳糖苷（18）作为糖基受体，完成了在鼠李吡喃糖残基的2位（31）或4位（21）特异性脱氧的O-α-L-鼠李吡喃糖基-（1→2）-α-D-吡喃半乳糖苷甲酯的合成。五-O-苯甲酰化二糖前体经苯硫代碳酸酯活化、随后进行巴顿还原和泽普林酯交换反应得到31，而21是通过脱氧单糖供体与18缩合，然后对产物进行脱苯甲酰基反应获得的。
