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[摘要]:On the basis of the assignment of methylene proton signals in H-1 NMR and determination of the chemical shift difference (Delta delta), the relative configuration of 1,3,n-methyl-branched deoxypropionates can be determined directly. Comparison of the chemical shifts in the corresponding syn- and anti-configured compound pairs shows remarkable differences, while the absolute values depend on the presence and nature of adjacent functional groups. The determination of the Delta delta values provides a reliable assessment of the relative configuration in 1,3,n-methyl-branched polypropionate chains and is even valid for macrocycles. |
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