(3aR,5R,6S,7R,7aR)-5-(hydroxymethyl)-2-methyl-5,6,7,7a-tetrahydro-3aH-pyrano[3,2-d][1,3]thiazole-6,7-diol
(3ar,5r,6s,7r,7ar)-5-(hydroxymethyl)-2-methyl-5,6,7,7a-tetrahydro-3ah-pyrano[3,2-d][1,3]thiazole-6,7-diol