Synthetic Studies on the Validamycins. I. Synthesis of β-D-Glucopyranosylvalidamine: 1L-2-<i>O</i>-(β-D-Glucopyranosyl)-(1,3,4/2,6)-4-amino-6-hydroxymethyl-1,2,3-cyclohexanetriol
β-D-Glucopyranosylvalidamine, the structure of which had first been assigned to a degradation product of validamycin A, was synthesized by condensation of a protected validamine with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide, followed by removal of protecting groups. The synthesized β-D-glucopyranoside was not identical with an authentic sample derived from the antibiotic.