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

R 1
3
1
HO
H
19 18
11
OH
6 7
8
O
12
O
14
16
R 3
15
OR 2
R1 R2 R3 R4
(136) H H CH3 CH3
(137) H CHO CH3 CH3
(138) H H CH2(OH) CH3
(139) H H CH2OC(O)CH3 CH3
(140) OC(O)CH3 H CH2(OH) CH3
(141) OH H CH2OC(O)CH3 CH2OC(O)CH3
19
HO
20
10
18
H
R 1
1
HO
19 18
11
6 7
O
OH
12
8
O
13
R 3
R 2
R 4
17
R1 R2 R3
(144) H H CH2CH(OH)CH3
(145) OH OH CH(CH3)2
OH
OH
3
1
OH
11
19 18 O
H
7
OH
12
8
O
R
(142) H
(143) C(O)CH3
11
12 15
HO
CH3O 11
12 15
HO
20
11
12 15
14
14
14
O
6
8
7
19
10
H
18
O
6
OH
7
19
10
H
18
O
OH
O
(146) (147) (148)
OH
O
16
CH2OCCH3 CH2OR 17
14
OH
63