N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
154
4 13 C NMR
154
4 13 C NMR
H 2 N
O
–
O
HN
+
H 2 N
NH 2
N
H
NH 3
+
O
OH
N
H
NH 3
+
O
O
–
N
N
H
NH 2
O
O
–
N
N
H
NH 3
+
O
O
–
N
N
H
NH 3
+
O
OH
N
H 2
+
OH
O
N
H 2
+
O
–
O
N
H
O
–
O
+
H 3 N
OH
O
HN
+
H 2 N
NH 2
N
H 2
+
HO
O
O
–
N
H 2
+
O
O
–
HO
H 2 N
O
–
O
HN
HN
NH 2
24.9
25.0
25.6
28.8
32.7
53.9
55.4
56.6
172.8
175.1
172.1
174.8
176.9
174.8
174.7
135.0
137.2
137.1
118.9
117.7
118.2
127.7
133.1
133.5
173.3
175.4
175.8
179.2
175.4
183.9
41.5
157.8
157.9
157.8
41.6
42.1
(pH 1.33)
(pH 1.27)
(pH 1.74)
(pH 7.87)
(pH 7.26)
(pH 7.82)
(pH 11.52)
(pH 9.80)
(pH 9.21)
(80 o C)
(in D 2 O/DCl)
28.0
54.0
47.4
47.2
47.2
57.7
71.1
24.4
24.8
24.8
73.9
38.5
26.2
29.0
30.1
53.6
55.7
29.4
30.0
30.0
41.9
61.0
61.0
62.3
62.4
64.5
56.1
56.1
56.0
27.2
28.2
108.7
114.2
125.8
127.6
122.9
124.5
120.3
121.8
119.3
120.5
112.7
114.2
137.3
138.6
127.7
128.9