The presence of two yellow, non-phenolio alkaloids, spermatheridine (I) and atherospenaidine (II), in the bark of Atherosuerma moschatm Labill. has already been reported (l), and they hare been shown to belong to the arall class of alkaloids which possess a 7-oxo-dibenzo(de,g) quinoline skeleton
(2). An examination of the phenol& alkaloids of A. moschatum has resulted in the isolation of anall quantities of a further yellcu &se, atheroline, m.p. 250-260' (decamp). Its i.r. spectrum had a carbonyl peak at 1639 cm-l, and its U.V. and risible light absorption spectra ahowed that it also belonged to the above-mentioned class of alkaloids (2).
A positive ferric chloride test and an absorption band at 3250 as-l in its i.r. spectrum indicated the presence of a phenolio hydroxy group.
Treatment of atheroline vith acetic anhydride in p-dine yielded [kcetylatheroline which crystallised from pyridine as yellow needles, m.p. WO-195' and analysed for C21H1706N with three nethory groups. In the araaatic proton region, the n.m.r. spectrus of O-acetylatheroline shoved three oneproton singlets at b7.ll, 8.20 and 8.80 ppm, and two one-proton doublets (J=6 cps) centred at b7.64 and 8.80 ppm respectively, These features are ccmpatible with structure (III), which has oxy aubstituente at p+ sitions 1,2,9 and 10. The singlet at high field may be assigned to H3