Preparation of methyl 2,4-diacetamido-2,4,6-trideoxy-α-D-ido-, α-D-talo-, α-D-altro-, and α-D-mannopyranoside

Abstract

Title compounds were prepared from methyl 2-O-acetyl-3,4-anhydro-6-deoxy-α-D-galactopyranoside (I). Solvolysis of I afforded methyl 3-O-acetyl-6-deoxy-α-D-gulopyranoside (II) from which in turn was prepared its 2,4-di-O-methanesulfonyl derivative III. The reaction of III with sodium azide undergoes under participation of the O-acetyl group in the position 3 and produces methyl 2,4-diazido-2,4,6-trideoxy-α-D-idopyranoside (V) that after hydrogenation and acetylation yields methyl 2,4-diacetamido-2,4,6-trideoxy-α-D-idopyranoside (VIII). Methyl 2,4-diacetamido-2,4,6-trideoxy-α-D-talopyranoside (XI) was prepared by its mesylation and by solvolysis of the product. Azidolysis of I, followed by hydrogenation and acetylation gave methyl 4-acetamido-4,6-dideoxy-α-D-glucopyranoside (XII). Its subsequent reaction with diethyl azodicarboxylate-triphenylphosphine mixture led to methyl 4-acetamido-2,3-anhydro-4,6-dideoxy-α-D-allopyranoside (XV). Mixture of methyl 4-acetamido-2-azido-2,4,6-trideoxy-α-D-altropyranoside (XVII) and its gluco- isomer XVIII is formed in the reaction of XV with sodium azide. Hydrogenation of XVII yields amino derivative XIX that in turn gives methyl 2,4-diacetamido-2,4,6-trideoxy-α-D-altropyranoside (XXI) by acetylation. Methyl 2,4-diacetamido-2,4,6-trideoxy-α-D-mannopyranoside (XXII) was prepared by its mesylation and solvolysis. All structures were confirmed by 1H and 13C NMR spectra.