Dehydroascorbic acid with amino acids

Reaction of 2-amino-2-deoxypentoses with pentane-2,4-dione and 1-phenyl-butane-1,3-dione afforded substituted pyrroles (e.g., 41) and the riboflavin analogue (42) was prepared by condensation of l>-ribose with 5-amino-o-cresol, followed by cyclocondensation of the product with violuric acid. Reaction of dehydroascorbic acid with o-phenylenediamine followed by aroylhydrazides afforded compounds of the type (43), the side-chains of which have been further elaborated. The acid derived by oxidation of 2,3 4,5-di-0-iso-... 

---