N-Araboascorbic acid

From the method of preparation of the analogs of L-ascorbic acid and from their close resemblance to L-ascorbic acid in respect to chemical properties and absorption data, all these derivatives were assumed by analogy to have the characteristic unsaturated five-membered ring system already proved to be present in L-ascorbic acid. In two cases, namely that of D-gluco- (XV) and n-araboascorbic acid (XXXIX) the assumption has proved correct. 

A recent study (Tl) showed that in Penicillium notatum, n-glucose-was converted to n-araboascorbic acid with 80 % of the activity in carbon 1, showing the possibility of formation of D-araboascorbic acid from D-glucose without rupture and inversion of the carbon chain. 

Methyl-D- araboascorbic acid Tr=C(C H,),— 3-Methyl-n-eryth-ronic acid... 

The procedure of Chen ef al. (C7) separated the ascorbic acid on paper using n-butanol or phenol saturated with oxalic acid to retard decomposition. A preliminary preparative separation could be used to concentrate the sample. Qualitative identification was made from the R/ of the spots located by spraying with 0.08 % 2,6-dichlorophenolindophe-nol, and quantitative analysis by elution with oxalic acid and titration with the same dye. Recoveries from urine and cress seedlings were 85 % or more at even the lowest concentrations tested (0.5 mg/ml), and the method could detect 1-2 fig ascorbic acid per cm of paper. The method clearly separated L-ascorbic acid and D-araboascorbic acid as well as hydroxytetronic acid, reductinic acid, and reductone. 

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