Studies related to bark extractives of some fir and spruce species, and synthesis and biosynthesis of indole alkaloids

Neil Douglas Westcott
1970
Part I of the thesis describes four investigations of some of the neutral components of bark extractives. The petroleum ether extract of grand fir [Abies grandis (Dougl.) Lindl.] was found to contain two triterpene lactones. The first compound, cyclo-grandisolide, was shown by chemical and spectroscopic considerations and confirmed by X-ray analysis to be (2 3R)-3a-methoxy-9,19-cyclo-9β-lanost-24-ene-26 ,23-lactone (38) . The second component, epi-cyclograndisolide, was isomeric with the first
more » ... ric with the first and was assigned as (23S)-3α-methoxy-9,19-cyclo-9 β- lanost-24-ene-26,23-lactone (43). In the second investigation, three triterpenes of the chloroform extract of Pacific silver fir [A. amabilis (Dougl.) Forbes] were examined. The main component, abieslactone, was known and had been assigned as (23R)-3α-methoxylanosta-9(11),24—diene-26,23-lactone (30). Chemical and spectroscopic evidence is considered which indicates that assignment to be incorrect and abieslactone is tentatively re-assigned as (23R)-3a-methoxy-9β-lanosta-7,24-diene-26,23-lactone (81). A minor component, AA₃ was assigned on the basis of methylation studies as 3-desmethylabieslactone or (23R)-3α-hydroxy-9β-lanosta-7,24-diene-26,23-lactone (83). Oxidation of AA₃ gave a ketone identical to the second minor component, AA₂, which is then (23R)-3-oxo-9β-lanosta-7,24-diene-26,23-lactone (82). The third investigation concerns the structure of W₄, a triterpene ketone from the petroleum ether extract of Western white spruce [Picea glauca (Moench) Voss. var. albertiana (S. Brown) Sarg.]. The structure tentatively assigned on the basis of spectroscopic evidence is 3β-methoxy-8α-serrat-13-en-21-one (91). The fourth investigation was a chemosystematic study of the petroleum ether extract of Engelmann spruce [P. engelmannii Parry]. The presence of methoxyserratene derivatives known to be present in other members of the same genus were not detected in the present investigation. Part II of the thesis describes synthetic endeavors leading to possible bio-intermediates [...]
doi:10.14288/1.0059947 fatcat:zgz6n4cntjf5plh2atbe77atle