1,4-Naphthoquinones, XIX: 2-, 3- and 6-Methyljuglone from Formylnaphthol Derivatives

Article abstract of DOI:10.1002/ardp.19893220912

The methylnaphthol derivatives 9 and 10 are suitable compounds for the synthesis of plumbagin, 6-methyljuglone (14) and 3-methylnaphthazarine (12). 9 and 10 are derived from 5 and 6 which are synthesized by formylation of the naphthols 2 and 3.As it was not possible to get the formylnaphthol 8 in the same way, isoplumbagin (18) was prepared by bromine-lithium exchange in the key compound 16 followed by methylation and oxidation.