university of kwazulu-natal faculty of science and agriculture school ...

19
O
20
9
11
4 6 7
OH
O
O
H
H
18
O
O
7'
6'
9'
4'
14'
17'
12'
20' O
OH
16'
14
16
O
17
O
H
O
OH
O
O
O
OH
OH
O
H
H
O
O
(49) (50)
O
H
O
OH
O
O
O
H
O
O
O
OH
(51) (52) (53)
Seventeen compounds with linear side-chains at C-13 instead of the isopropyl group,
compounds 54 to 69 were isolated from P. hereroensis, P. edulis, P. lanuginosus, P.
sanguineus and C. coerulescens (Table 6c). P. lanuginosus yielded the highest number
of compounds compared to the other species which yielded less than five compounds.
The side chains are either saturated as in 54, contain a double bond as in compounds 55-
63, an acetyl group as in compound 64 or an alcohol as in compounds 65, 68 and 69.
Compounds 57 and 61 and 65-69 have functional groups at C-3 with 66-69 being abeo-
abietanes where a methyl from C-4 has migrated to C-3.
O
O
H
O
O
O
OH
O
H
O
O
7
OH
H
H
7'
OH
O
O
H
O
O
45