Ten new compounds isolated from the heartwood of Combreturn psidioides have been shown to be 7-hydroxy-2,4,6-trimethoxy-, 7-hydroxy-2,3,4,6-tetramethoxy-, 2,7-dihydroxy-3,4,6-trimethoxy-, and 2.6.7-trihydroxy-3.4dimethoxy-phenanthrene, the 9.1 O-dihydro-derivatives of these four compounds, and 4'- hydroxy-3,4,5-trimethoxyand 4,4'-dihydroxy-3,5-dimethoxybibenzyl. Salisbury, Rhodesia WE have described the isolation and structure elucidation of eight new phenanthrenes or 9, lo-dihydrophenanthrenes from the heartwood of Combretum apiculatum and Combretum moZZe,l together with a bibenzyl from the latter. We now report on the heartwood extractives of
Combretum p ~i d i o i d e s , ~which contain fourteen phenanthrenes or 9,10-dihydrophenanthrenes, eight of which are new, and three phenolic bibenzyls, of which two are new.Light petroleum extraction removed an oily material from the heartwood. The subsequent ether extract, which consisted entirely of phenolic material, was chromatographed on t.1.c. plates yielding red gums from eight of the bands. These crude phenolic compounds exhibited no carbonyl absorption in the i.r. Acetylation followed by t.1.c. yielded crystalline acetates from bands B and E, amorphous acetates from bands C and G, and gums from bands A, D, F, and H. The designations (A-H) represent the order in which the phenols ran on the t.1.c. plates.The acetate from band A separated into two bands on t.1.c. plates. The upper band gave an amorphous solid, which was shown by mass spectrometry and by n.m.r. to be a mixture of phenol (A,) acetate (30%) and its dihydro-derivative, phenol (A,) acetate (70%). Dehydrogenation of the amorphous acetate gave a single crystalline compound, phenol (A,) acetate (C,,H1,O,) which showed one acetoxy-and three methoxy-groups in the n.m.r. spectrum (Table 2) together with six aromatic protons, two of which appear as singlets, apparently para to one another, two as a two-proton singlet (H-9, H-lo), with the remaining two as a pair of doublets ( J 2 Hz) exhibiting meta-coupling. A comparison of the chemical shifts of the aromatic protons of phenol (A,) acetate with those of 2,4,6,7-tetramethoxyphenanthrene (Table 2) suggests phenol (A,) to have the same substitution pattern as the latter and that the acetoxy-group is a t C-7. Hydrolysis of phenol (A,) acetate yielded the free phenol which on deuteriation in deuterium oxide under basic conditions, followed by acetylation gave a monodeuteriated species (demonstrated by mass spectrometry) showing two metacoupled protons (H-l, H-3), the two-proton singlet (H-9, H-lo), and the low-field proton (H-5) in the n.m.r.