Some biochemically relevant properties of N-substituted fructosamines derived from amino-acids and N-arylglucosylamines

Abstract

The N-substituted fructosamine (isoglucosamine) fructose-phenylalanine (N-(l[image]-carboxy-2[image]-phenylethyl)amino-l-desoxyfructose) was prepared in amorphous form with impurities present in small amounts only. Its characteristic reactions were also given by N-p-tolyl-D-fructosamine, a crystalline N-arylfructosamine. The outstanding property of N-substituted fructosamines tested is the ease with which upon mild acid treatment (2 [image] acetic acid) they form 5-hydroxymethylfurfuralde-hyde, in the case of the phenylalanine compound, up to 63% of the theoretical yield. Since under the same conditions even the acid-labile D-fructose does not yield appreciable amts. of 5-hydroxymethylfurfuraldehyde, its production by dilute acetic acid may be used as a tracer for N-substituted fructosamines in natural products.