Biology Reference
In-Depth Information
Table 17.1 The six- and five-membered N-heterocyclic templates
No. of touted
modulators
No. exhibiting
activity
No. exhibiting greater than
88 % kill
Template
2.
0
$
Nicotinic acid
(i.e. Niacin)
14
7
Nicotinamide
13
12
2
12
0
Picolinic acid
14
3
2-Pyridine aldehyde
3
1
0
2-Pyridine aldoxime
2
2
2
2-Oxypyridine
21
18
11
4-Oxopyridine
2
2
0
Pyridinium ion
27
24
14
2,2
0
-Bipyridine
7
7
2
2,2
0
-DipyridyIdisulfide
4
3
2
8-Hydroxyquinoline
15
11
4
Quinoline
58
58
5
1,10-Phenanthroline
14
10
10
Phenanthridine
5
5
5
Pyridazine
2
1
0
Quinoxaline
4
4
0
Pyrrole
:i:i
31
12
Total
247
215
79
similarity to nicotinic acid; 2-oxypyridine and 4-oxopyridine because of their
structural similarity to pyridine; 2,3-dipyridyl, 2,4-dipyridyl and 4,4
0
-dipyridyl
because they are structural isomers of 2,2
0
-dipyridyl; 2,2
0
-dipyridylamine and 2,2
0
-
dipyridyl disulfide because of their structural similarity to 2,2
0
-dipyridyl; quinoline
because of its structural similarity to 5-OH-quinoline; and 4,7-phenanthroline
because it is a structural isomer of 1,10-phenanthroline. Pyridinium (Rebeiz
et al.
1991
) was also selected because of its structural similarity to pyridine, and
because a database of herbicidal compounds available from lSI (Philadelphia, PA,
USA), listed several pyridinium compounds with general herbicidal properties.
Finally 1,2-diazine and 1,4-benzodiazine were also chosen from the lSI database
for the same reason as pyridinium. Some of the above compounds are depicted in
Table
17.1
depicted above.
17.6.3.4 Discovery of a Pyrrole-Based TDPH Template
Rapid testing for TDPH activity of representative members of the aforementioned
chemical categories, that will be referred to hereafter as TDPH templates or
templates for short, unraveled interesting TDPH properties. A closer examination
of the chemical structure of the various templates revealed that they fell into two
separate categories: (a) those that were structurally related to half a tetrapyrrole
molecule such as the phenanthrolines (Rebeiz et al.
1991
); and (b) those that were
Search WWH ::
Custom Search