CH 3
R 1
A
B
C
D
E
8
7
5
9
4
1
6
13
3
2
11
17
12
14
15
18
19
22
21
16
20
24
26
23
25
27
10
28
OH
OH OH
OH
OH
32
35
A
B
C
D
E
22
29
30
Diagenesis
Defunctionalization
Bond stereochemistry
not specified
Bond directed into page (α)
Bond directed out of page (β)
R
Bacteriohopanepolyols (b)
(a) General hopanoid structure
2α− methylhopanes (c)
Fig. 4.15 Formation of 2-α methylhopanes. (a) General skeleton of hopanes; (b) R ¼ H or CH 3 ; (c) R1 ¼ H or CH 3 to nC 5 H 11 (Modified and
redrawn from Summons et al. 1999)
HO
HO
R
Cholesterol
stigmasterol
Steranes
R = H : cholestane
R = Et : stigmastane
Diagenesis/Defunctionalization
Fig. 4.16 Sterols and steranes
4 For Three Billion Years, Microorganisms Were the Only Inhabitants of the Earth
95
R 1
A
B
C
D
E
8
7
5
9
4
1
6
13
3
2
11
17
12
14
15
18
19
22
21
16
20
24
26
23
25
27
10
28
OH
OH OH
OH
OH
32
35
A
B
C
D
E
22
29
30
Diagenesis
Defunctionalization
Bond stereochemistry
not specified
Bond directed into page (α)
Bond directed out of page (β)
R
Bacteriohopanepolyols (b)
(a) General hopanoid structure
2α− methylhopanes (c)
Fig. 4.15 Formation of 2-α methylhopanes. (a) General skeleton of hopanes; (b) R ¼ H or CH 3 ; (c) R1 ¼ H or CH 3 to nC 5 H 11 (Modified and
redrawn from Summons et al. 1999)
HO
HO
R
Cholesterol
stigmasterol
Steranes
R = H : cholestane
R = Et : stigmastane
Diagenesis/Defunctionalization
Fig. 4.16 Sterols and steranes
4 For Three Billion Years, Microorganisms Were the Only Inhabitants of the Earth
95