A Novel Entry to 4,7-Indoloquinones via the Fremy's Salt Oxidative Degradation of 4-Formyl-7-hydroxyindoles

Article abstract of DOI:10.1021/jo00028a035

A novel synthetic approach toward 4-formyl-7-hydroxyindoles and 4,7-indoloquinones is described.Basically, two major operations need to be carried out, namely: (1) ozonization of the appropriately protected 4-amino-5-hydroxyindenes leading eventually to 4-formyl-7-hydroxyindoles and (2) Fremy's salt promoted oxidative degradation of the later compounds to the desired 4,7-indoloquinones.A formal synthesis of PDE I and PDE II has been achieved.