The preparation of 6-deoxy-3-O-methyl-6-nitro-D-altrose

The title compound(9) a new nitro sugar and potential starting-point for the synthesis of hitherto unknown stereoisomers in the deoxynitroinositol series, was prepared by a sequence of high-yielding reactions. Methyl 2.3-anhydro-4.6-O- benzylidene-α-D-mannopyranoside was converted into methyl 3-O-methyl-α-D-altropyranoside(3) by the action of sodium methoxide followed by debenzylidenation esssentially according to established procedures. Acetolysis of3 and subsequent Zemple´n transesterification gave syrupy 3-O-methyl-D-altrose, from which the furanoid 1,2:5.6-di-O-isopropylidene and 1,2-O-isopropylidene(7) derivatives were prepared by standard acetonation and partial Hydrolysis Periodate oxidation of 7, and addition of nitromethane to the product. furnished crystalline 6-deoxy-1.2-O-isopropylidene-3-O-methyl-6-nitro-β-D-altrofuranose(8) as the chief epimer. Deacetonation of8 by trifluoroacetic acid9 in crystalline form.