A novel entry to 4, 7-indoloquinones via the Fremy's salt oxidative degradation of 4-formyl-7-hydroxyindoles

JM Saa, C Marti, A Garcia-Raso

Index: Saa, Jose M.; Marti, Catalina; Garcia-Raso, Angel Journal of Organic Chemistry, 1992 , vol. 57, # 2 p. 589 - 594

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Citation Number: 16

Abstract

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 I1 has been ...