Riboflavin prodn. from D-glucose - via gluconic acid and N-D-ribityl-3,4-xylidine

摘要

Prepn. of riboflavin (I) comprises (a) oxidising D-glucose to O-gluconic acid (II) or its alkali metal salt; (b) treating (II) with hypochlorite to form D-arabinose (III); (c) converting (III) to D-ribose (IV) with a hexavalent Mo cpd.; (d) hydrogenating (IV) in the presence of nitroxylene or xylidine to form N-D-ribityl-3,4-xylidine (V); (e) converting (V) to 1-D-ribitylamino-3,4-dimethyl-6-phenylazobenzene (VI) by reaction with the corresp. diazonium salt; and (f) reacting (VI) with barbituric acid.. The process gives high yields (up to 30% overall) using inexpensive and nontoxic reactants.