Re-examination of Nucleophilic Substitutionin Chlorokojic Acid
摘要:
Chlorokojic acid was reacted with S2O32-, NO3-, N-3(-), I-, and SCN-. Only the three latter nucleophiles substituted the chlorine atom in the 2-CH2Cl group of kojic acid. In none of the products nucleophilic substitution at position 6 of the 4-pyrone could be found. Regular substituion of chlorokojic acid with I- (iodokojic acid), N-3(-) (azidokojic acid), and SCN- (thiocyanato and isothiocyanato kojic acids) was accompanied by formation of allomaltol. Reaction pathways for the formation of allomaltol and 6-substituted allomaltol derivatives are proposed. The latter has been formerly discovered in the reaction of chlorokojic acid with secondary amines.