Nitrogen-containing carbohydrate derivatives : Part IV. Studies on the optical rotatory dispersion and circular dichroism of carbohydrate C-nitro alcohols. III

Abstract

The optical rotatory dispersion and circular dichroism of carbohydrate C-nitro alcohols were measured. Evidence is presented that the signs of the Cotton effect about 310 mμ and of the ellipticity of the 310 mμ band are closely related to the absolute configuration at C-2 of carbohydrate C-nitro alcohols. Carbohydrate C-nitro alcohols in which the asymmetric carbon atom adjacent to the nitro methyl group belongs to the s-series exhibit positive Cotton effects and positive c.d. maxima (or shoulders), whereas C-nitro alcohols in which the adjacent carbon atom is of the r-series show negative Cotton effects and negative c.d. maxima (or shoulders). These deductions permit the ready determination of the absolute configuration of epimeric nitro alcohols obtained by the nitromethane synthesis for elongation of carbohydrate chains.