Naphthoquinone mono- and di-methide lactones
Abstract
Monolactones which are derivatives of 7-hydroxynaphtho[1,8-bc]pyran-2,6-dione are obtained by reaction of simple juglones with ethyl chloroformylacetate, and by condensation of mandelic acid with 2,6-dibromo-1,5-dihydroxynaphthalene. Dilactones are formed by condensation of mandelic acid with 1,5-dihydroxynaphthalene, which yields 3,8-diphenylnaphtho[1,2-b : 5,6-b′]difuran-2,7-dione and/or 3,8-diphenylnaphtho[1,8-bc : 4,5-b′c′]dipyran-2,7-dione; with 2,3-dihydroxynaphthalene it gives 3,8-diphenylnaphtho[2,1-b: 3,4-b′]difuran-2,9-dione.