Facile and efficient synthesis of 7,10-dihydroxy-6H-pyrazolo[4,5,1-de]acridin-6-one via hypervalent iodine oxidation

摘要

An improved synthetic procedure for 5,8-dibromo-7,10-dihydroxy-2-methyl-6H-pyrazolo[4,5,1-de]acridin-6-one(4 ), an intermediate of a novel class of antitumor agents, was developed. An effective introduction of a hydroxy group to the C10 of 5,8-dibromo-7-hydroxy-2-methyl-6H-pyrazolo[4,5,1-de]acridin-6-one (2b) was accomplished in two steps via the oxidation of 2b to the corresponding quinone using hypervalent iodine reagent in an acidic medium, followed by reduction of the resulting quinone upon treatment with aqueous sodium hydrosulfite.