Pentacyclic and Higher Systems

From roots of Daniella revoluta, a bisnaphthoquinone pigment, dian-nelinone, was isolated. The compound is easily transformed into a dinaphtho [1,2-6 2 -d]furan-7,12-dione upon irradiation in chloroform or ethanol (65AJC218). 

3 -Dihydroxy-2,2 -binaphthalene is transformed into 139 upon dehydration. The compound is obtained along with a small amount of both o-quinones 141 and 142 in hot acetic and sulfuric acid. However, compound 

141 becomes the main product if dehydration takes place at room temperature in the presence of concentrated sulfuric acid (36JA1212). 

An analog of 138 was prepared in low yield by a Friedel-Crafts reaction between 1,4-benzoquinone and veratrole (33CB792). 

Derivatives of 138 and some heptacyclic analogs were prepared from 2,3,5,6-tetrachloro-1,4-benzoquinone and phenols (57JOC342, 57MI2 60T135). When present, pyridine is incorporated into the newly formed molecule, and quinones like 144 were obtained (58MI2). 

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