Synthesis of Biologically Active Carba-oligosaccharides

Synthesis of Biologically Active Carba-oligosaccharides 

Synthetic studies of validamycins were initially devoted to establishing the structure of validamycin A. The structure in which a ) -D-glucopyranosyl group is attached to 0-3 of the validamine residue was initially proposed on the basis of degradative studies. However, the original structure was re- 

condensation of di-O-isopropylidenevalienamine (359) with cyclohexene epoxide or cyclohexadiene epoxide was carried out in 2-propanol. 

Racemic validoxylamine B was synthesized as the per-A, 0-acetyl derivative (356) by coupling 230 with 359 in DMF-2-propanol for 4 days at 50°, 

condensation of the epoxide 230 with the amine 358 was conducted, and dehydration of the condensate (361) was attempted by chlorination with sulfonyl or sulfuryl chloride in pyridine, followed by elimination with 

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VIII. Synthesis of Biologically Active Carba-oligosaccharides. 74... 

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