(S)-3-Dimethyl­amino-2-{(4S,5R)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-1,3-dioxolan-4-yl}-2-hydroxy­propanoic acid

The Kiliani reaction on 1-de-oxy-(N,N-dimethyl-amino)-d-fructose, itself readily available from reaction of dimethyl-amine and d-glucose, proceeded to give access to the title β-sugar amino acid, C(15)H(27)NO(7). X-ray crystallography determined the stereochemistry at the newly formed chiral center. There are two mol-ecules in the asymmetric unit; they are related by a pseudo-twofold rotation axis and have very similar geometries, differing only in the conformation of one of the acetonide rings. All the acetonide rings adopt envelope conformations; the flap atom is oxygen in three of the rings, but carbon in one of them. There are two strong hydrogen bonds between the two independent mol-ecules, and further weak hydrogen bonds link the mol-ecules to form infinite chains running parallel to the a axis.