Synthesis and antimycobacterial activity of some N1-[1-[3-aryl-1- (pyridin-2-, 3-, or 4-yl)-3-oxo]propyl]-2-pyridinecarboxamidrazones

Article abstract of DOI:10.1016/S0014-827X(99)00097-X

N¹-[1-[3-aryl-1-(pyridin-2-,3-, and 4-yl)-3-oxo]propyl]-2- pyridinecarboxamidrazone derivatives were synthesized and tested for their in vitro antimycobacterial activity. Some compounds showed interesting activity against a strain of Mycobacter

Full text of DOI:10.1016/S0014-827X(99)00097-X

www.elsevier.nl/locate/farmac
Il Farmaco 54 (1999) 761–767
Synthesis and antimycobacterial activity of some
N1-[1-[3-aryl-1-(pyridin-2-, 3-, or 4-yl)-
3-oxo]propyl]-2-pyridinecarboxamidrazones
Maria Grazia Mamolo a,*, Valeria Falagiani a, Luciano Vio a, Elena Banfi b
a Dipartimento di Scienze Farmaceutiche, Uni6ersita` di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
b Dipartimento di Scienze Biomediche (Sez.Microbiologia), Uni6ersita` di Trieste, Via Fleming 22, I-34127 Trieste, Italy
Abstract
N1-[1-[3-aryl-1-(pyridin-2-,3-, and 4-yl)-3-oxo]propyl]-2-pyridinecarboxamidrazone derivatives were synthesized and tested for
their in vitro antimycobacterial activity. Some compounds showed interesting activity against a strain of Mycobacterium
tuberculosis and a strain of Mycobacterium a6ium. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Pyridine-2-carboxamidrazone; Antimycobacterial activity
1. Introduction
of the antimycobacterial properties of compounds
characterized by the presence of the pyridine-2-car-
boxamidrazone moiety, we synthesized a series of new
N1-substituted pyridine-2-carboxamidrazone deriva-
tives 22–42 (Table 1). All synthesized compounds
were tested for their antimycobacterial activity to-
wards a strain of M. tuberculosis and a strain of M.
a6ium. The activity of these compounds against a
strain of Candida albicans and one of Escherichia coli
was also determined.
The increase of reported cases of tuberculosis even
in developed countries, along with the emergence of
multidrug-resistant (MDR) Mycobacterium tuberculo-
sis strains, has refocused attention on this illness. An
important factor in the re-emergence of tuberculosis
was the spread of acquired immunodeficiency syn-
drome (AIDS). Another consequence of the spread of
AIDS has been the emergence of infections associated
with mycobacteria other than tuberculosis (MOTT),
among which members belonging to the M. a6ium
intracellular complex (MAC) frequently produce
severe disseminated infections in HIV-infected pa-
tients. In previous papers [1–5] we described some
pyridine-2-carboxamidrazone and pyridine-4-carbox-
amidrazone derivatives. Among those compounds
some showed interesting in vitro activity against M.
tuberculosis H37Rv and against strains of M. tubercu-
losis isolated from human bronchial aspirates, some
of which were resistant to isoniazid, rifampicin and
ofloxacin. It is noteworthy that some of those com-
pounds exhibited inhibitory activity towards a human
strain of M. a6ium resistant to the primary drugs
isoniazid, rifampicin and ofloxacin. In consideration
2. Chemistry
The synthesis of N1-[1-[3-aryl-1-(pyridin-2-, 3-, or
4-yl)-3-oxo]propyl]-2-pyridinecarboxamidrazones (22–
42) (Table 1) was carried out (Scheme 1) by adding
2-pyridinecarboxamidrazone (1a) to 1-aryl-3-(pyridin-
2-yl)-propenones (1–7), 1-aryl-3-(pyridin-3-yl)-pro-
penones (8–14) and 1-aryl-3-(pyridin-4-yl)-propenones
(15–21), variously substituted on the phenyl residue.
Pyridine-2-carboxamidrazone (1a) was prepared by di-
rect action of hydrazine on 2-cyanopyridine, accord-
ing to the previously proposed method [6]. The
a,b-unsaturated ketones (1–21) (Table 2) were pre-
pared by the conventional method described in Sec-
tion 3.
* Corresponding author. Fax: +39-040-52 572.
E-mail address: mamolo@univ.trieste.it (M.G. Mamolo)
0014-827X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0014-827X(99)00097-X

762
M.G. Mamolo et al. / Il Farmaco 54 (1999) 761–767
3. Experimental
3.1. Chemistry
3.1.1. General procedure for the preparation of
1-aryl-3-( pyridin-2-,3-,or 4-yl)-propenones (1–21)
To a solution of 5 g (46 mmol) of 2-, 3- or 4-
pyridinecarboxaldehyde in 5 ml of methanol and 9 ml
of 10% sodium hydroxide, the appropriate acetophe-
none (23 mmol) was added dropwise under cooling
(0–5°C) and stirring. After complete addition, the reac-
tion mixture was stirred for 1–2 h keeping the tempera-
ture at about 10°C. The resulting solid was collected by
filtration and washed thoroughly with water. The solid
was then dried and recrystallized from ethanol (Table 2).
Melting points (m.p.) were determined with a Bu¨chi
510 capillary apparatus, and are uncorrected. Infrared
spectra in Nujol mulls were recorded on a Jasco FT 200
spectrophotometer. Proton nuclear magnetic resonance
(1H NMR) spectra were determined on a Varian Gem-
ini 200 spectrophotometer; chemical shifts are reported
as l (ppm) relative to tetramethylsilane as the internal
standard, deuterochloroform as the solvent. Reaction
courses and product mixture were routinely monitored
by thin-layer chromatography (TLC) on silica gel pre-
coated F254 Merck plates. EI-MS spectra (70 eV) were
taken on a VG 7070 spectrometer. Elemental analyses
(C, H, N) were performed on a Carlo Erba analyzer
and were within 90.3 from the theoretical value.
3.1.2. N1-[1-[3-Phenyl-1-(pyridin-2-yl)-3-oxo]propyl]-
2-pyridinecarboxamidrazone (22)
To the solution of the a,b-unsaturated ketone 1 in 20
ml of absolute ethanol, 0.60 g (4.4 mmol) of 2-pyridin-
carboxyamidrazone dissolved in 20 ml of the same
solvent was added: the reaction mixture was stirred at
Table 1
Yields and melting points for compounds 22–42
Comp.
Het
R
Yield (%)
M.p. (°C)
Formula
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
H
3-Cl
4-Cl
3,4-Cl2
3-CH3
4-CH3
4-Ph
H
55
35
22
50
31
39
76
21
25
21
58
25
37
36
44
40
37
40
47
38
32
120
122
135
126
98
C20H19N5O
C20H18N5OCl
C20H18N5OCl
C20H17N5OCl2
C21H21N5O
C21H21N5O
C26H23N5O
C20H19N5O
C20H18N5OCl
C20H18N5OCl
C20H17N5OCl2
C21H21N5O
C21H21N5O
C26H23N5O
C20H19N5O
C20H18N5OCl
C20H18N5OCl
C20H17N5OCl2
C21H21N5O
C21H21N5O
C26H23N5O
125
147
124
150
140
135
130
124
160
124
137
130
150
125
160
150
3-Cl
4-Cl
3,4-Cl2
3-CH3
4-CH3
4-Ph
H
3-Cl
4-Cl
3,4-Cl2
3-CH3
4-CH3
4-Ph

M.G. Mamolo et al. / Il Farmaco 54 (1999) 761–767
763
Scheme 1.
room temperature (r.t.). After 24 h, the precipitate
was collected by filtration and recrystallized from ab-
solute ethanol to obtain 2.75 g (55%) of 22; m.p.
120°C.
arom. and pyr.). MS: m/z 378,380 [M+]. Anal. (C20-
H18N5OCl): C, H, N.
3.1.4. N1-[1-[3-(4-Chlorophenyl)-1-(pyridin-2-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (24)
1
IR (Nujol, cm−1): 3440, 3340, 3200; 1680; 1610. H
1
NMR (CDCl3/TMS): l 3.40 (dd, 1H, CHH, J=16.87
and 5.82 Hz), 3.90 (dd, 1H, CHH, J=16.87 and 7.69
Hz), 3.80–4.45 (br, s, 1H, NH, disappearing on
deuteration), 5.0 (m, 1H, CH), 5.30 (s, 2H, NH, dis-
appearing on deuteration), 7.20–8.70 (m, 13H, arom.
and pyr.). MS: m/z 345 [M+]. Anal. (C20H19N5O): C,
H, N.
In an analogous way the following compounds
(22–42) have been prepared. Yields and melting point
are reported in Table 1.
IR (Nujol, cm−1): 3430, 3320, 3180; 1680; 1620. H
NMR (CDCl3/TMS): l 3.65 (dd, 1H, CHH, J=16.70
and 5.92 Hz), 3.90 (dd, 1H, CHH, J=16.70 and 7.02
Hz), 3.85–4.55 (br, s, 1H, NH, disappearing on
deuteration), 5.10 (m, 1H, CH), 5.30 (s, 2H, NH,
disappearing on deuteration), 7.20–8.60 (m, 12H,
arom. and pyr.). MS: m/z 378,380 [M+]. Anal.
(C20H18N5OCl): C, H, N.
3.1.5. N1-[1-[3-(3,4-Dichlorophenyl)-1-(pyridin-2-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (25)
3.1.3. N1-[1-[3-(3-Chlorophenyl)-1-(pyridin-2-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (23)
IR (Nujol, cm−1): 3440, 3320, 3210; 1680; 1610. H
1
NMR (CDCl3/TMS): (l) 3.60 (dd, 1H, CHH, J=
16.74 and 6.36 Hz), 3.85 (dd, 1H, CHH, J=16.74
and 6.66 Hz), 3.80–4.75 (br, s, 1H, NH, disappearing
on deuteration), 5.10 (m, 1H, CH), 5.35 (s, 2H, NH,
disappearing on deuteration), 7.20–8.60 (m, 11H,
arom. and pyr.). MS: m/z 414 [M+]. Anal.
(C20H17N5OCl2): C, H, N.
1
IR (Nujol, cm−1): 3400, 3310, 3220; 1670; 1610. H
NMR (CDCl3/TMS): l3.65 (dd, 1H, CHH, J=16.75
and 5.94 Hz), 3.90 (dd, 1H, CHH, J=16.75 and 7.03
Hz), 3.70–4.30 (br, s, 1H, NH, disappearing on
deuteration), 5.05 (m, 1H, CH), 5.30 (s, 2H, NH,
disappearing on deuteration), 7.20–8.60 (m, 12H,

764
M.G. Mamolo et al. / Il Farmaco 54 (1999) 761–767
3.1.6. N1-[1-[3-(3-Methylphenyl)-1-(pyridin-2-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (26)
and 8.9 Hz), 3.70 (dd, 1H, CHH, J=16.18 and 9.9 Hz),
3.80–4.70 (br, s, 1H, NH, disappearing on deuteration),
4.90 (m, 1H, CH), 5.30 (s, 2H, NH, disappearing on
deuteration), 7.30–8.70 (m, 17H, arom. and pyr.). MS:
m/z 421 [M+]. Anal. (C26H23N5O): C, H, N.
IR (Nujol, cm−1): 3400, 3320, 3180; 1680; 1620. H
NMR (CDCl3/TMS): l 2.40 (s, 3H, CH3), 3.70 (dd, 1H,
CHH, J=16.77 and 6.9 Hz), 3.85 (dd, 1H, CHH,
J=16.77 and 7.02 Hz), 3.75–4.35 (br, s, 1H, NH,
disappearing on deuteration), 5.10 (m, 1H, CH), 5.40
(s, 2H, NH, disappearing on deuteration), 7.30–8.70
(m, 12H, arom. and pyr.). MS: m/z 359 [M+]. Anal.
(C21H21N5O): C, H, N.
1
3.1.9. N1-[1-[3-Phenyl-1-(pyridin-3-yl)-1-oxo]-
propyl]-2-pyridinecarboxamidrazone (29)
1
IR (Nujol, cm−1): 3440, 3300, 3200; 1670; 1620. H
NMR (CDCl3/TMS): l 3.30 (dd, 1H, CHH, J=17.10
and 5.62 Hz), 4.0 (dd, 1H, CHH, J=17.10 and 7.63
Hz), 3.80–4.60 (br, s, 1H, NH, disappearing on deuter-
ation), 5.0 (m, 1H, CH), 5.40 (s, 2H, NH, disappearing
on deuteration), 7.20–8.90 (m, 13H, arom. and pyr.).
MS: m/z 345 [M+]. Anal. (C20H19N5O): C, H, N.
3.1.7. N1-[1-[3-(4-Methylphenyl)-1-(pyridin-2-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (27)
IR (Nujol, cm−1): 3400, 3320, 3200; 1680; 1610. H
1
NMR (CDCl3/TMS): (l) 2.40 (s, 3H, CH3), 3.65 (dd,
1H, CHH, J=16.92 and 6.31 Hz), 3.90 (dd, 1H, CHH,
J=16.92 and 6.45 Hz), 3.70–4.30 (br, s, 1H, NH,
disappearing on deuteration), 5.10 (m, 1H, CH), 5.30
(s, 2H, NH, disappearing on deuteration), 7.20–8.60
(m, 12H, arom. and pyr.). MS: m/z 359 [M+]. Anal.
(C21H21N5O): C, H, N.
3.1.10. N1-[1-[3-(3-Chlorophenyl)-1-(pyridin-3-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (30)
1
IR (Nujol, cm−1): 3400, 3300, 3200; 1680; 1620. H
NMR (CDCl3/TMS): l 3.35 (dd, 1H, CHH, J=16.70
and 6.2 Hz), 4.00 (dd, 1H, CHH, J=16.70 and 6.85
Hz), 4.10–4.80 (br, s, 1H, NH, disappearing on deu-
teration), 5.0 (m, 1H, CH), 5.35 (s, 2H, NH, disap-
pearing on deuteration), 7.20–8.85 (m, 12H, arom.
and pyr.). MS: m/z 378,380 [M+]. Anal. (C20H18N5OCl):
C, H, N.
3.1.8. N1-[1-[3-(4-Biphenylyl)-1-(pyridin-2-yl)-3-oxo]-
propyl]-2-pyridinecarboxamidrazone (28)
IR (Nujol, cm−1): 3420, 3320, 3220; 1680; 1620. H
1
NMR (CDCl3/TMS): l 3.10 (dd, 1H, CHH, J=16.18
Table 2
Yields, melting points and IR data for compounds 1–21
Comp.
Het
R
Yield (%)
M.p. (°C)
IR cm−1 (CꢀO)
Formula
Ref.
[7]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
2-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
3-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
4-pyridyl
H
3-Cl
4-Cl
3,4-Cl2
3-CH3
4-CH3
4-Ph
H
35
67
85
92
70
86
68
40
47
63
33
75
63
36
35
69
67
68
21
60
85
60–61
65
85–86
154
41
55
130
101–102
120
129
145
60
79
140
70–71
106–109
150
1670
1665
1670
1660
1670
1675
1660
1670
1680
1665
1680
1680
1670
1680
1660
1675
1670
1670
1665
1660
1670
C14H11NO
C14H10NOCl
C
14H10NOCl
[7]
[8]
C14H9NOCl2
C15H13NO
C15H13NO
C20H15NO
C14H11NO
C14H10NOCl
C14H10NOCl
C14H9NOCl2
C15H13NO
C15H13NO
C20H15NO
C14H11NO
C14H10NOCl
C14H10NOCl
C14H9NOCl2
C15H13NO
C15H13NO
C20H15NO
[7]
3-Cl
4-Cl
[8]
[8]
3,4-Cl2
3-CH3
4-CH3
4-Ph
H
3-Cl
4-Cl
3,4-Cl2
3-CH3
4-CH3
4-Ph
[7]
[9]
[8]
[8]
[9]
[10]
164
113–114
83–85
158

M.G. Mamolo et al. / Il Farmaco 54 (1999) 761–767
765
3.1.11. N1-[1-[3-(4-Chlorophenyl)-1-(pyridin-3-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (31)
and 6.34 Hz), 4.10 (dd, 1H, CHH, J=16.99 and 6.48
Hz), 3.95–4.85 (br, s, 1H, NH, disappearing on deuter-
ation), 5.05 (m, 1H, CH), 5.50 (s, 2H, NH, disappearing
on deuteration), 7.10–8.80 (m, 13H, arom. and pyr.).
MS: m/z 345 [M+]. Anal. (C20H19N5O): C, H, N.
IR (Nujol, cm−1): 3380, 3280, 3200; 1680; 1620. H
NMR (CDCl3/TMS): l 3.35 (dd, 1H, CHH, J=16.81
and 6.43 Hz), 3.80 (dd, 1H, CHH, J=16.81 and 6.51
Hz), 4.20–4.90 (br, s, 1H, NH, disappearing on deuter-
ation), 5.30 (m, 1H, CH), 5.35 (s, 2H, NH, disappearing
on deuteration), 7.10–8.80 (m, 12H, arom. and pyr.).
MS: m/z 378, 380 [M+]. Anal. (C20H18N5OCl): C, H, N.
1
3.1.17. N1-[1-[3-(3-Chlorophenyl)-1-(pyridin-4-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (37)
1
IR (Nujol, cm−1): 3400, 3330, 3220; 1685; 1600. H
NMR (CDCl3/TMS): l 3.30 (dd, 1H, CHH, J=16.75
and 5.94 Hz), 3.90 (dd, 1H, CHH, J=16.75 and 7.03
Hz), 3.75–4.40 (br, s, 1H, NH, disappearing on deuter-
ation), 5.00 (m, 1H, CH), 5.35 (s, 2H, NH, disappearing
on deuteration), 7.20–8.60 (m, 12H, arom. and pyr.).
MS: m/z 378,380 [M+]. Anal. (C20H18N5OCl): C, H, N.
3.1.12. N1-[1-[3-(3,4-Dichlorophenyl)-1-(pyridin-3-yl)-
3-oxo]propyl]-2-pyridinecarboxamidrazone (32)
1
IR (Nujol, cm−1): 3460, 3360, 3200; 1690; 1630. H
NMR (CDCl3/TMS): l 3.25 (dd, 1H, CHH, J=16.75
and 5.98 Hz), 3.95 (dd, 1H, CHH, J=16.75 and 7.01
Hz), 3.90–4.70 (br, s, 1H, NH, disappearing on deuter-
ation), 5.0 (m, 1H, CH), 5.30 (s, 2H, NH, disappearing
on deuteration), 7.15–8.80 (m, 11H, arom. and pyr.).
MS: m/z 414 [M+]. Anal. (C20H17N5OCl2): C, H, N.
3.1.18. N1-[1-[3-(4-Chlorophenyl)-1-(pyridin-4-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (38)
1
IR (Nujol, cm−1): 3440, 3320, 3200; 1680; 1630. H
3.1.13. N1-[1-[3-(3-Methylphenyl)-1-(pyridin-3-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (33)
NMR (CDCl3/TMS): l 3.30 (dd, 1H, CHH, J=16.85
and 5.90 Hz), 3.85 (dd, 1H, CHH, J=16.85 and 7.10
Hz), 3.75–4.40 (br, s, 1H, NH, disappearing on deuter-
ation), 4.95 (m, 1H, CH), 5.35 (s, 2H, NH, disappearing
on deuteration), 7.20–8.70 (m, 12H, arom. and pyr.).
MS: m/z 378,380 [M+]. Anal. (C20H18N5OCl): C, H, N.
1
IR (Nujol, cm−1): 3440, 3280, 3180; 1680; 1610. H
NMR (CDCl3/TMS): l 2.40 (s, 3H, CH3), 3.35 (dd, 1H,
CHH, J=16.93 and 5.75 Hz), 3.70 (dd, 1H, CHH,
J=16.93 and 7.27 Hz), 3.75–4.50 (br, s, 1H, NH,
disappearing on deuteration), 5.0 (m, 1H, CH), 5.20 (s,
2H, NH, disappearing on deuteration), 7.30–8.85 (m,
12H, arom. and pyr.). MS: m/z 359 [M+]. Anal.
(C21H21N5O): C, H, N.
3.1.19. N1-[1-[3-(3,4-Dichlorophenyl)-1-(pyridin-4-yl)-
3-oxo]propyl]-2-pyridinecarboxamidrazone (39)
1
IR (Nujol, cm−1): 3440, 3360, 3280; 1680; 1610. H
NMR (CDCl3/TMS): l 3.25 (dd, 1H, CHH, J=16.57
and 9.1 Hz), 3.90 (dd, 1H, CHH, J=16.57 and 9.87
Hz), 3.75–4.80 (br, s, 1H, NH, disappearing on deuter-
ation), 4.95 (m, 1H, CH), 5.30 (s, 2H, NH, disappearing
on deuteration), 7.10–8.85 (m, 11H, arom. and pyr.).
MS: m/z 414 [M+]. Anal. (C20H17N5OCl2): C, H, N.
3.1.14. N1-[1-[3-(4-Methylphenyl)-1-(pyridin-3-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (34)
1
IR (Nujol, cm−1): 3440, 3310, 3200; 1680; 1620. H
NMR (CDCl3/TMS): l 2.40 (s, 3H, CH3), 3.40 (dd, 1H,
CHH, J=16.98 and 5.5 Hz), 3.90 (dd, 1H, CHH,
J=16.98 and 7.54 Hz),), 3.80–4.70 (br, s, 1H, NH,
disappearing on deuteration), 5.05 (m, 1H, CH), 5.30 (s,
2H, NH, disappearing on deuteration), 7.30–8.80 (m,
12H, arom. and pyr.). MS: m/z 359 [M+]. Anal.
(C21H21N5O): C, H, N.
3.1.20. N1-[1-[3-(3-Methylphenyl)-1-(pyridin-4-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (40)
1
IR (Nujol, cm−1): 3440, 3300, 3200; 1670; 1620. H
NMR (CDCl3/TMS): l 2.50 (s, 3H, CH3), 3.40 (dd, 1H,
CHH, J=17.13 and 6.31 Hz), 3.75 (dd, 1H, CHH,
J=17.13 and 6.52 Hz), 3.65–4.50 (br, s, 1H, NH,
disappearing on deuteration), 5.05 (m, 1H, CH), 5.25 (s,
2H, NH, disappearing on deuteration), 7.10–8.70 (m,
12H, arom. and pyr.). MS: m/z 359 [M+]. Anal.
(C21H21N5O): C, H, N.
3.1.15. N1-[1-[3-(4-Biphenylyl)-1-(pyridin-3-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (35)
IR (Nujol, cm−1): 3420, 3310, 3210; 1660; 1630. H
1
NMR (CDCl3/TMS): l 3.10 (dd, 1H, CHH, J=16.41
and 8.6 Hz), 3.65 (dd, 1H, CHH, J=16.41 and 10.21
Hz), 4.10–4.90 (br, s, 1H, NH, disappearing on deuter-
ation), 4.90 (m, 1H, CH), 5.30 (s, 2H, NH, disappearing
on deuteration), 7.20–8.90 (m, 17H, arom. and pyr.).
MS: m/z 421 [M+]. Anal. (C26H23N5O): C, H, N.
3.1.21. N1-[1-[3-(4-Methylphenyl)-1-(pyridin-4-yl)-3-
oxo]propyl]-2-pyridinecarboxamidrazone (41)
1
IR (Nujol, cm−1): 3400, 3280, 3200; 1680; 1620. H
3.1.16. N1-[1-[3-Phenyl-1-(pyridin-4-yl)-3-oxo]propyl]-
2-pyridinecarboxamidrazone (36)
NMR (CDCl3/TMS): l 2.45 (s, 3H, CH3), 3.40 (dd, 1H,
CHH, J=16.76 and 5.95 Hz), 3.80 (dd, 1H, CHH,
J=16.76 and 7.83 Hz),), 3.70–4.40 (br, s, 1H, NH,
disappearing on deuteration), 5.10 (m, 1H, CH), 5.30
IR (Nujol, cm−1): 3440, 3340, 3200; 1680; 1620. H
1
NMR (CDCl3/TMS): l 3.35 (dd, 1H, CHH, J=16.99

766
M.G. Mamolo et al. / Il Farmaco 54 (1999) 761–767
Table 3
The minimal inhibitory concentration (MIC) was
defined as the lowest chemical dilution associated with
at least a 99% reduction in the number of the visible
colonies. The results are shown in Tables 3 and 4.
The other microbial strains tested were E. coli strain
ATCC 25922 and C. albicans strain C873, a recent
clinical isolate. The E. coli strain was grown overnight
in Mueller Hinton broth and the fungal strain was
grown overnight in Sabouraud dextrose broth, the test
inocula were prepared diluting the overnight suspension
to a density of 104 microorganisms/ml. The MIC deter-
minations were performed by the agar dilution method;
Mueller Hinton agar (Oxoid) and Sabouraud Dextrose
agar (Oxoid) were used for bacterial and fungal strains,
respectively, to prepare quadrant plates with serial
dimethylsulfoxide twofold dilutions of the different
chemicals tested. A 20 ml sample of each 104/ml micro-
bial suspension was inoculated onto each chemical con-
taining quadrant. Control plates consisted of Mueller
Hinton agar or Sabouraud dextrose agar alone, culture
medium with dimethylsulfoxide and culture medium
with known antimicrobial drugs, like ampicillin (10
mg/disk) for bacterial strains or econazole (10 mg/disk)
for C. albicans. All the plates were then incubated at
37°C overnight. The results obtained are shown in
Table 5.
Activity of the carboxamidrazone derivatives 22–42 against M. tuber-
culosis H37Rv (MIC, mg/ml) a
Comp.
MIC (mg/ml)
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
4
16
4
2
2
1
8
16
8
1
16
2
1
32
8
4
2
2
8
8
16
a M. tuberculosis strain resulted sensitive to isoniazid (5 mg disk),
rifampicin (25 mg disk) and ofloxacin (30 mg disk).
(s, 2H, NH, disappearing on deuteration), 7.20–8.90
(m, 12H, arom. and pyr.). MS: m/z 359 [M+]. Anal.
(C21H21N5O): C, H, N.
3.1.22. N1-[1-[3-(4-Biphenylyl)-1-(pyridin-4-yl)-3-oxo]-
propyl]-2-pyridinecarboxamidrazone (42)
Table 4
Activity of the carboxamidrazone derivatives 22–42 against M. a6ium
1
IR (Nujol, cm−1): 3440, 3280, 3200; 1670; 1600. H
485 (MIC, mg/ml) a
NMR (CDCl3/TMS): l 3.15 (dd, 1H, CHH, J=16.15
and 9.2 Hz), 3.60 (dd, 1H, CHH, J=16.15 and 10.76
Hz), 3.80–4.40 (br, s, 1H, NH, disappearing on deuter-
ation), 4.95 (m, 1H, CH), 5.35 (s, 2H, NH, disappear-
ing on deuteration), 7.20–8.80 (m, 17H, arom. and
pyr.). MS: m/z 421 [M+]. Anal. (C26H23N5O): C, H, N.
Comp.
MIC (mg/ml)
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
80
80
8
8
16
80
32
8
32
80
80
16
16
16
16
8
8
8
16
16
8
3.2. Microbiology
The determination of antimycobacterial activity was
performed by viable count employing the agar dilution
method [11]. Midlebrook and Cohn 7H10 agar, supple-
mented with Midlebrook OADC enrichment, was used
to prepare quadrant plates with serial dimethylsulfoxide
twofold dilutions of the different chemicals tested.
We employed two strains of Mycobacterium spp.: M.
tuberculosis reference strain H37Rv and M. a6ium, strain
485, from our bacterial collection, emulsified in diluting
fluid containing 0.2% fatty acid free albumin and 0.02%
polysorbate 80, pH 6.9.
Control plates were included with known antimy-
cobacterial drugs; all plates were incubated at 35°C in
5% CO2 for 3–4 weeks.
a M. a6ium strain resulted resistant to isoniazid (5 mg disk) and
rifampicin (30 mg disk).

M.G. Mamolo et al. / Il Farmaco 54 (1999) 761–767
767
Table 5
pounds exhibit a significant activity (MIC=8 mg/ml)
towards the tested strain of M. a6ium (Table 4). On
the other hand, the activity of the synthesized com-
pounds towards a strain of C. albicans and E. coli is
very feeble or completely absent. This evidence confi-
rms the importance of the 2-pyridinecarboxamidra-
zone moiety with respect to the antimycobacterial
activity and suggests that other structural modifica-
tions of the groups linked to the N1-amidrazone atom
may produce more active compounds.
Activity of the carboxamidrazone derivatives 22–42 against E. coli
and C. albicans C873 (MIC, mg/ml) a
Comp. MIC E. coli (mg/ml)
MIC C. albicans (mg/ml)
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
\160
\160
\160
\160
\160
\160
\160
\160
\160
\160
\160
\160
\160
\160
80
20
80
40
20
80
80
\160
\160
80
80
80
\160
\160
\160
80
Acknowledgements
The authors would like to thank Dr M. Cebulec
for the microanalyses. Financial support from
MURST (Cofinanziamento Programma Nazionale
1997) is gratefully acknowledged.
\160
\160
\160
\160
\160
\160
40
80
20
80
References
80
\160
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