Methyl α-d-Tagatopyranoside

d-Tagatose, classified as a rare sugar, exhibits notable biological activities, including its function as a low-calorie sweetener. The three-dimensional configuration of carbohydrates is crucial for elucidating their functional properties. Numerous studies have reported the X-ray crystallographic structures of d-tagatose and its derivatives bearing a free anomeric hydroxy group. However, there are no reports on the X-ray crystallographic structure of d-tagatosides featuring a glycosidic linkage at the anomeric position. In this study, we synthesized methyl α-d-tagatopyranoside from d-tagatose and successfully determined its X-ray crystallographic structure, revealing its 5C2 conformation.