DISPLACEMENT IN METHYL FURANOSIDE COMPOUNDS . SYNTHESIS OF 2,3,5-TRIAMINO-2,3,5-TRIDESOXY-D-ARABINOSE AND 2,3,5-TRIAMINO-2,3,5-TRIDESOXY-D-XYLOSE

Methyl 5-azido-5-deoxy-2,3-di-O-p-tolylsulfonyl-β-d-ribofuranoside was treated with sodium azide in N,N-dimethylformamide for 2.5 h at 145° to give the diazido compound 3, characterised as crystalline di-N-benzoyl derivative. Methyl 5-benzamido-2,3-benzoylepimino-2,3,5-trideoxy-β-d-lyxofuranoside (7) was obtained in 61 % yield from diazide 3 by treatment with lithium aluminum hydride, followed by direct benzoylation. Azidolysis of 7 with sodium azide in N,N-dimethylformamide gave two compounds in a ratio 1.8:1, which were readily converted, after hydrogenation and N-benzoylation to the corresponding methyl 2,3,5-tribenzamido-2,3,5-trideoxy-β-d-arabinoside and -xyloside, respectively. The lack of reactivity of the tosyloxy group at C-2 towards SN2-type displacements is discussed. © 1969.