Dapagliflozin sugar dimer impurity 1

Dapagliflozin sugar dimer impurity 1 arises from non-enzymatic dimerization of the glucosamine moiety in dapagliflozin, forming a glycosidic linkage between C1 and C6 hydroxyl groups of adjacent sugar units. This dimer retains the 1,5-dihydroxy-2-methylpyridine-4-carboxylic acid scaffold of the parent compound, with a β-glycosidic bond stabilizing the dimeric structure. It functions as an HPLC reference standard for quantifying sugar dimerization byproducts in dapagliflozin active pharmaceutical ingredient synthesis.