Naturally occurring quinones. Part XIV. The quinonoid constituents of Pyrola media Sw. (Pyrolaceae)

Abstract

The leaves of Pyrola media contain monotropein, 4-methoxyphenol and its methyl ether, toluquinol, and a glucoside of 5,8-dihydro-2,7-dimethylnaphthalene-1,4-diol, probably renifolin; also present are the quinones chimaphilin, 2-methyl-5-(3-methylbut-2-enyl)-1,4-benzoquinone, 5-geranyl-2-methyl-1,4-benzoquinone, and an unidentified quinone possibly related to renifolin. The coexistence of these compounds suggests that chimaphilin is derived in vivo from 2-methyl-5-(3-methylbut-2-enyl)-1,4-benzoquinone, and in vitro the latter can be cyclised to the former in the presence of boron trifluoride.