Glucose with glyoxal

Although no D-glucosone was obtained by the action of formaldehyde on D-glucose phenylosazone,19 Briill28 successfully decomposed the osazone with an excess of pyruvic acid. An improved procedure has been described, and the decomposition of D-glucose phenylosazone with glyoxal has been reported.18... 

Figure 10. GLC (A) and TLC (B) of the isolated 2,4-DNP-positive substance from the reaction mixture of glucose with t-butylamine in ethanol. GLC conditions XE-60 column at 110 °C. In a, 2,4-DNP-positive spots of the reaction mixture were developed with chloroform-ethanol-water (5 2 1). In b, 2,4-DNP derivatives were developed with benzene-hexane-ethyl acetate (5 2 1) on silica gel plate. Key to A and B (1), isolated substance (2), glycolaldehyde (3), glyoxal. (Reproduced with permission from Ref. 4.)...

These findings confirmed that glyoxal dicyclohexylimine is one of the products from the reaction of glucose with cyclohexylamine in ethanol. Although the formation of similar imines by the reaction of glucose with other alkylamines was not directly established, detection of glyoxal by silica gel TLC, shown in Fig. 9, in all of these cases seems to justify the assumption that the two-carbon diimines are always among the products of this kind of reaction, under the conditions employed. 

Figure 14. Formation in glyoxal dialkylimine, 3-deoxyglucosone, and the free radical from glucose with t-butylamine (each 1 in ethanol. Key , glyoxal dialkylimine O, 3-deoxyglucosone A, free radical , browning (absorbancy at 420 run). (Reproduced with permission from Ref. 4.)...

SUBSTITUTED PYRAZINE 1-OXIDES FROM 2-AMINO-2-DEOXY-D-GLUCOSE (OR MANNOSE) OXIME WITH GLYOXAL... 

D- rafro-Tetrahydroxybutyl)pyrazine 1-oxide (7) has been prepared by Fujii and Kobatake (543, 544) by the condensation of 2-amino-2-deoxy-D-glucose oxime (6) or 2-amino-2-deoxy-D-mannose oxime with glyoxal in water at room temperature. 

Preparations of pyrazine A -oxides containing extranuclear hydroxyl groups are also described in Qiapter III as follows Section III.l, 2-aminopyrazine 1-oxides from a-amino nitriles and a-hydroxyimino carbonyl compounds (540, 541) Section III.2, 3-substituted pyrazine 1-oxides from 2-amino-2-deoxy-D-glucose(or mannose) oxime with glyoxal (543, 544) and Section III.5, ring closure of the C-C-N-C-C-N-0 system (553). 

Reaction Mixtures of Bovine Serum Albumin with Glucose or Glyoxal in the Absence/Presence of Ascorbic Acid... 

This condensation with formaldehyde as well as with methyl glyoxal is confirmed by the formation of dimethylimidazole when ammonia acts upon glucose and acetaldehyde. 

Figure 13. Formation of glucosyl-n-butylamine and glyoxal dialkylimine during the reaction of glucose (0.25 MJ with t-butylamine (1 MJ in ethanol. Key 0, glucosylamine A, imine 9, browning.

As mentioned previously, we have found that certain product(s) could be extracted with ether from the early stages of the reaction between glucose and n-butylamine in aqueous system, and have assigned glyoxal dialkylimine as the main product. Recently, it has been shown that the ether-extractable substance is not itself a radical product but when it is dissolved in an aqueous solution of ascorbic acid or acidic ferrocyanide, an... 

Because a-dicarbonyl compounds are particularly reactive, Weenen and Apeldoom57 specifically looked for these compounds by means of derivatisation with o-diaminobenzene among the butanol-soluble fragmentation products formed in 15 systems (glucose, fructose, xylose, 3-deoxyglucosone, or fructosylalanine without amine or with alanine or cyclohexylamine 1 h, 100 °C, phosphate buffer, pH 8). Four a-dicarbonyls were obtained glyoxal, 2-oxopropanal, butanedione, and 2,3-pentanedione. 

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