Novel 1,2,3-triazole derivatives for use against mycobacterium tuberculosis H37Rv (ATCC 27294) strain

Article abstract of DOI:10.1021/jm2003624

The purpose of this study was to prepare various 4-substituted N-phenyl-1,2,3-triazole derivatives using click chemistry. The derivatives were screened in vitro for antimicrobial activity against Mycobacterium tuberculosis strain H37Rv (ATCC 27294) using

Full text of DOI:10.1021/jm2003624

ARTICLE
pubs.acs.org/jmc
Novel 1,2,3-Triazole Derivatives for Use against
Mycobacterium tuberculosis H37Rv (ATCC 27294) Strain
Nubia Boechat,*,† Vitor F. Ferreira,‡ Sabrina B. Ferreira,‡ Maria de Lourdes G. Ferreira,† Fernando de C. da Silva,‡
Monica M. Bastos,† Marilia dos S. Costa,† Maria Cristina S. Lourenc-o,‡ Angelo C. Pinto,|| Antoniana U. Krettli,^
Anna Caroline Aguiar,^ Brunno M. Teixeira,‡ Nathalia V. da Silva,‡ Priscila R. C. Martins,‡
||
Flavio Augusto F. M. Bezerra,§ Ane Louise S. Camilo,† Gerson P. da Silva,†, and Carolina C. P. Costa†
†Fundac-~ao Oswaldo Cruz, Instituto de Tecnologia em Fꢀarmacos, Departamento de Síntese Org^anica, Manguinhos,
21041-250 Rio de Janeiro, RJ, Brazil
‡Fundac-~ao Oswaldo Cruz, Instituto de Pesquisa Clínica Evandro Chagas-IPEC, Laboratꢀorio de Bacteriologia e Bioensaios em
Micobactꢀerias, 21045-900, Rio de Janeiro, RJ, Brazil
§Fundac-~ao Oswaldo Cruz, Instituto de Pesquisa Clínica Evandro Chagas-IPEC, Laboratꢀorio de Bacteriologia e Bioensaios em
Micobactꢀerias, 21045-900 Rio de Janeiro, RJ, Brazil
Universidade Federal do Rio de Janeiro, Instituto de Química, Departamento de Química Org^anica, Cidade Universitꢀaria,
21941-909 Rio de Janeiro, RJ, Brazil
^Fundac-~ao Oswaldo Cruz, Laboratꢀorio de Malꢀaria, Centro de Pesquisas Renꢀe Rachou, 30190-002 Belo Horizonte, MG, Brazil
ABSTRACT: The purpose of this study was to prepare various
4-substituted N-phenyl-1,2,3-triazole derivatives using click
chemistry. The derivatives were screened in vitro for antimi-
crobial activity against Mycobacterium tuberculosis strain H37Rv
(ATCC 27294) using the Alamar Blue susceptibility test. The
activity was expressed as the minimum inhibitory concentra-
tion (MIC) in μg/mL (μM). Derivatives of isoniazid (INH),
(E)-N0-[(1-aryl)-1H-1,2,3-triazole-4-yl)methylene] isonicotinoyl
hydrazides, exhibited significant activity with MIC values ranging from 2.5 to 0.62 μg/mL. In addition, they displayed low
cytotoxicity against liver cells (hepatoma HepG2) and kidney cells (BGM), thereby providing a high therapeutic index. The results
demonstrated the potential and importance of developing new INH derivatives to treat mycobacterial infections.
’ INTRODUCTION
(approximately two years). With an extended treatment period,
however, patients have an increased risk of toxicity and the
treatment costs are approximately 100 times higher than the
typical treatment of TB (which is conducted for six to nine
months).3 INH is an active oral drug that exhibits bacteriostatic
effects on bacillus and is highly active against Mycobacterium
tuberculosis.4 The MIC of INH is notably low (0.02 to 0.06 μg/mL),
which contributes to its effectiveness.
The concept of making structural analogues of INH became
increasingly important in the 1990s after the discovery of its
mechanism of action; INH interferes with the synthesis of mycolic
acid, one of the chemical pathways responsible for the produc-
tion of cell walls in M. tuberculosis. Thus, INH inhibits the
bacteria from multiplying and causes bacterial death. INH is
metabolized in the human liver and forms compounds, such as
hydrazine, that are toxic to the organs and the central nervous
system.5ꢀ7 Because INH is a critical drug in the therapeutic
arsenal8ꢀ11 for TB treatment, efforts are being made to develop
of new INH derivatives with greater activity, lower toxicity, and
fewer side effects than INH.12ꢀ14
Tuberculosis (TB) is an infectious disease that has affected
humanity for more than five millennia.1The etiologic agent of
TB, Mycobacterium tuberculosis (or Koch bacillus), is suspected of
causing a large number of deaths despite the availability of effective
chemotherapy and the Bacille CalmetteꢀGuꢀerin (BCG) vaccine.2
It is estimated that 70% of the population in poor countries is
infected with the Koch bacillus, and 7.5 million new cases and
2.8 million deaths are reported each year. The high rate of disease
occurrence in these countries is closely related to the precarious
living conditions encountered there. The two factors associated
with the spread of TB are human immunodeficiency virus (HIV)
infection and the emergence of M. tuberculosis strains that are
resistant to one or more drugs (“multiple drug resistant” M.
tuberculosis, MDR-TB). The ever-increasing number of MDR-
TB cases has caused great concern because they contribute to an
increase in deaths from TB and are often associated with HIV
infection. It is estimated that one-third of the 42 million
individuals infected with HIV are coinfected with M. tuberculosis;
most people infected with HIV develop TB as the first manifesta-
tion of acquired immunodeficiency syndrome (AIDS).
The presence of MDR-TB reflects a weakness in TB control,
but this weakness can be treated with extended chemotherapy
Received: March 18, 2011
Published: July 21, 2011
r
2011 American Chemical Society
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Journal of Medicinal Chemistry
ARTICLE
The INH molecule was previously incorporated onto arylox-
yacetonitriles, giving isonicotinoylhydrazones that showed significant
tuberculostatic activity.12 Bukowski and co-workers prepared
isonicotinoyl hydrazides that were active against M. tuberculosis
H37Rv and M. tuberculosis 210 isolated from patients who were
resistant to INH, ethambutol, and rifampicin at 3.13 μg/mL.13
Additionally, other compounds with a halogen-substituted phenyl
group showed even greater activity.14 Therefore, it is possible to
attach chemical groups that are important in drug entry to INH and
thus make M. tuberculosis strains more susceptible to this drug.15
We have recently published our findings on the tuberculostatic
activity of a series of 1,2,3-triazoles with MIC values of approxi-
mately 2.5 μg/mL.16 These compounds were designed from
observations of the antimicrobial activity present in different
classes of compounds that contained the basic N1-phenylazole
subunit.17 In continuing the search for new tuberculostatic
compounds, the goal was to obtain compounds 3t, 4aꢀo, 4r,
5aꢀo, 6p, 7p, 8cꢀd, 8pꢀs, 9d, 9r, 9t, 10a, 10c, 10iꢀj, and
10mꢀo. In the present study, we evaluated the activity of
novel 4-substituted N-phenyl-1,2,3-triazole derivatives against
M. tuberculosis H37Rv as well as their in vitro cytotoxicity.
(1H NMR), 13C NMR, infrared spectroscopy (FTIR), mass
spectroscopy, and elemental analysis (CHN).
Minimum Inhibitory Concentration. The tuberculostatic
activities of compounds 3t, 5aꢀo, 6p, 7p, 8cꢀd, 8pꢀs, 9d, 9r,
9t, 10a, 10c, 10iꢀj, 10mꢀo, and their precursors 3aꢀs and
4aꢀo, 4r were assessed against the M. tuberculosis H37Rv strain
(ATCC 27294), which is susceptible to both rifampin and INH.
The biological study was carried out using the Microplate Alamar
Blue Assay (MABA), which is nontoxic, uses thermally stable
reagents, and shows strong correlation and proportionality with
the BACTEC MGIT 960 system (Mycobacterium Growth
Indicator Tube, Becton Dickinson Company, MD, USA).26ꢀ28
This colorimetric method uses the Alamar Blue resazurin-based
oxidationꢀreduction indicator to obtain drug susceptibility
measurements for bacteria. A blue color in the well was inter-
preted as indicating no bacterial growth, a pink color was scored
as growth, and purple indicated growth inhibition. Compounds
showing 90% inhibition in the primary screen were considered
active and retested at a lower concentration against M. tuberculosis
(ATCC 27294 H37Rv) to determine the actual MIC. The MIC
was defined as the lowest drug concentration that prevented
a change of color from blue to pink. The positive controls
used were rifampicin and INH. All determinations were per-
formed in triplicate, and the values shown in Table 1 are the
averages.
’ MATERIALS AND METHODS
Chemistry. When preparing 4-carboxaldehyde-1,2,3-triazoles
(4aꢀo, 4r), a synthetic route was utilized that used aromatic
azides (2aꢀo) previously obtained by a diazotization reaction18
of corresponding anilines (1aꢀo) and further reacted with
terminal alkynes.
Cytotoxicity. The cytotoxic activity of 1,2,3-triazoles was
assayed only on compounds with MIC e 12.5 μg/mL (4c,
5aꢀo, and 10o). The cytotoxicity was tested against hepatoma
cells (HEPG2) and kidney basal cells (BGM) using the MTT
((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
The methodology for obtaining the triazoles (3aꢀs, 6p, and 7p)
was based on the Huisgen 1,3-dipolar cycloaddition reaction.19
To obtain only the 1,4-regioisomers, click chemistry reaction
conditions using Cu(I) as a catalyst were utilized. In addition to
increasing the reaction rate, the copper catalyst provided full
control over reaction regioselectivity, which led to the produc-
tion of only the 1,4-regioisomers.20As observed by Sharpless, the
speed of the reaction and the yields are much higher in this
method than in the traditional method, achieving 80% to 100%
regioselectivity.21 The following 4-carboxaldehyde-1,2,3-triazoles
(4aꢀo, 4r) were prepared by oxidation of the products 3aꢀs
using 2-iodoxybenzoic acid (IBX).22
The synthesis of isonicotinoyl hydrazide derivatives (5aꢀo)
was accomplished through a Schiff reaction between the appropriate
4-carboxaldehyde-1,2,3-triazoles (4aꢀo, 4r) and INH, as de-
scribed in the general procedure (Scheme 1). To obtain deriva-
tives 8cꢀd, 8pꢀs, 9d, and 9r, fluorination of substrates 3cꢀd,
3pꢀs, 4d, and 4r with dimethylaminosulfur trifluoride (DAST)
was performed. This reagent has been widely used due to its high
selectivity for fluorination of alcohols, aldehydes, and ketones.23
The derivatives 3t and 9t were obtained from substrates
substituted with a cyano group (3r and 9r) through reaction
with classical thiosemicarbazones in trifluoroacetic acid.24
To synthesize the 4-vinyl-1,2,3-triazoles (10a, 10c, 10iꢀj,
10mꢀo), the respective aldehydes (4a, 4c, 4iꢀj, and 4mꢀo)
were treated with methyltriphenylphosphonium bromide and
sodium hydride (NaH), leading to the products in good yields.
Although 4-vinyl-1,2,3-triazoles have been reported in the litera-
ture, the Wittig reaction was used here for the preparation of a
series of these compounds.25
bromide) assay. The results are summarized in Table 2.
’ RESULTS AND DISCUSSION
The synthetic route was initiated with the preparation of
aromatic azides. Aromatic amines and sodium nitrite were
appropriately combined to form diazonium salts, which were
subsequently converted into azide (Scheme 1). Aromatic azides
were obtained as yellow oils with yields ranging from 63% to
100%. The azides were used directly in the next step without
purification to prevent degradation. The chemical structures
of the azides were confirmed by analyzing the crude product
using FTIR. Analysis showed a strong absorption band at
2099ꢀ2100 cmꢀ1, referring to the stretch vibrations of the N3
bond of the azido group.
The synthesis of triazoles 3aꢀs involved the 1,3-dipolar
cycloaddition reaction between propargyl alcohol and aromatic
azides catalyzed by Cu(I). Copper sulfate (CuSO4) and sodium
ascorbate guided the regioselectivity. To obtain derivatives 6p
and 7p, cycloadditions were conducted using methyl propiolate
and 3,3,3-trifluoro-1-propyne. Reactions were performed under
magnetic stirring at room temperature and were protected from
light due to the photosensitivity of the aromatic azides. After
purification in a flash-type column, triazole compounds were
obtained as white or yellow crystals with yields ranging from 30%
to 82%. Triazoles (3aꢀs, 6p, 7p) were identified using FTIR and
showed the absence of stretching vibrations of the azide group
and the presence of bands related to axial deformation of the
OH bond. In the 1H NMR spectra, the signals of the respective
protons of the synthesized compounds were verified on the
basis of their chemical shifts, multiplicities, and coupling
constants. The triazole protons were observed as a singlet at
All of the compounds were obtained with good yields and
were fully characterized by 1H nuclear magnetic resonance
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Journal of Medicinal Chemistry
ARTICLE
Scheme 1. Synthetic Route for the Preparation of 1,2,3-Triazole Derivativesa
a Reagents and conditions: (i) NaNO2, HCl 10%; NaN3, 2ꢀ4 h, rt. (ii) propargyl alcohol, CuSO4, sodium ascorbate, H2O:t-butanol, 3 h, rt; (iii) IBX/
DMSO, 3 h, rt; (iv) NH2NHC(O)C5H4N, MeOH, 48 h, rt; (v) methyl propiolate, CuSO4, sodium ascorbate, H2O:t-butanol, 24 h, rt; (vi) 3,3,3-
trifluoro-1-propyne, CuSO4, sodium ascorbate, H2O:t-butanol, 4 days, rt; (vii) DAST, CH2Cl2, 4 days, rt; (viii) DAST, CH2Cl2, 24 h, rt; (ix)
thiosemicarbazide, CF3COOH, 24 h, 60 ꢀC; (x) methyltriphenylphosphonium bromide, NaH, THF, 3ꢀ4 hours, rt.
7.96 to 8.05 ppm, whereas the CH2 group was a doublet at
4.57ꢀ5.46 ppm. The 6p derivative showed characteristic
1H and 13C NMR signals at 3.90 and 160.2 ppm, respectively;
these signals corresponded to the methyl group and the ester
carbonyl. Compound 7p was confirmed by 19F NMR and
showed a characteristic signal at ꢀ59.9 ppm that confirmed
the presence of the trifluoromethyl group.
For the preparation of fluorinated derivatives 8cꢀd, 8pꢀs, 9d,
and 9r, DAST was used as the fluorinating agent. The reaction
was carried out under magnetic stirring at room temperature and
led to the formation of products in good yields. The 19F NMR
spectra of monofluoro products showed characteristic signals
between ꢀ207 and ꢀ206 ppm. The 13C NMR spectra showed
signals between 75.2 and 76.1 ppm with fluorine coupling
constants in the range of 160 Hz. These signals confirmed the
presence of one fluorine atom. The preparation of compounds 3t
and 9t was performed by reacting aromatic nitrile derivatives with
thiosemicarbazide in boiling trifluoroacetic acid to give 2-amino-
5-aryl-1,3,4-thiadiazoles.24 Good yields were obtained, although
an extended reaction time was required. Spectroscopic analysis
confirmed the formation of these products. Amine (NH2)
protons were observed as a singlet at 7.56 ppm, and elemental
analyses were consistent with the structures.
1,2,3-Triazole alcohols (3aꢀo, 3r) were further oxidized to
aldehydes (4aꢀo, 4r) using IBX in dimethyl sulfoxide (DMSO).
Compounds were purified by silica gel flash-type column chro-
matography, and the triazole aldehydes were obtained as white
or light-yellow crystals in yields ranging from 55% to 100%.
1
Structures were confirmed by FTIR, H NMR, and 13C NMR.
The FTIR showed no bands relating to axial deformation of the
OH bond and contained characteristic bands of carbonyl group
stretching from the aldehydes between 1690 and 1704 cmꢀ1
.
The 1H NMR spectra showed singlet signals between 10.0 and
9.9 ppm, corresponding to the aldehyde hydrogens. Signals
between 8.00 and 8.10 ppm were assigned to the triazole
hydrogens. 13C NMR spectra also showed signals in the region
of 185.0 ppm, corresponding to the carbonyl carbons.
The syntheses of the isonicotinoyl hydrazide derivatives
(5aꢀo) were performed with the appropriate aldehyde 1,2,3-
triazoles (4aꢀo) and INH, as described in the general procedure.
Reaction mixtures were maintained at room temperature, leading
to desired compounds 5aꢀo in 52ꢀ99% yield. The FTIR spectra
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Journal of Medicinal Chemistry
ARTICLE
Table 1. The in Vitro Activity Expressed by MIC in μg/mL
(μM) of Compounds 3aꢀt, 4aꢀo, 4r, 5aꢀo, 6p, 7p, 8cꢀd,
8pꢀs, 9d, 9r, 9t, 10a, 10c, 10iꢀj, and 10mꢀo against M.
tuberculosis H37Rv (ATCC-27294) Strain
Table 2. The Cytotoxicity of the Compounds Is Expressed
by MDL50 in μg/mL (μM), and Selectivity Index Calculated
Using Two Cells Lines
MDL50 μg/mL
mean ( SD
selectivity index
entry
MIC
entry
MIC
isoniazid
rifampicin
3a
0.06 (0.437)
1.0 (1.21)
>100
4o
5a
> 100
2.5 (8.5)
1.25 (4.0)
0.62 (1.8)
0.62 (1.8)
1.25 (3.8)
1.25 (4.0)
0.62 (2.0)
2.5 (8.1)
0.62 (1.8)
2.5 (7.7)
1.25 (3.8)
0.62 (1.9)
2.5 (6.9)
1.25 (3.4)
>100
compd
HepG2
BGM
HepG2
BGM
5b
5c
4c
5h
5m
5b
5c
5j
71 ( 1
314 ( 0.5
>1000
97 ( 18
>1000
>1000
>1000
>1000
>1000
>1000
>1000
262 ( 25
>1000
>1000
>1000
>1000
>1000
>1000
>1000
6
8
3b
3c
>100
126
400
>1612
>800
>1612
>400
>321
>800
422
>100
5d
5e
>1612
>800
>1612
>400
>321
NTa
200
3d
3e
>100
>1000
>100
5f
>1000
3f
>100
5g
5h
5i
>1000
3g
>100
10o
5l
>1000
NTa
3h
3i
>100
>100
5j
5g
5i
124 ( 21
>1000
3j
>100
5l
>1612
>400
94
>1612
>400
>800
>800
>800
>400
>1612
3l
>100
5m
5n
5o
6p
7p
8c
5n
5f
>1000
3m
3n
3o
3p
3q
3r
>100
118 ( 14
263 ( 75
>1000
>100
5e
5o
5a
5d
210
>100
>800
>400
>1612
>100
50.0 (177.2)
100.0 (472.5)
100.0 (472.5)
100.0 (406.3)
>100
>1000
>100
>1000
>100
8d
8p
8q
8r
a NT = not tested.
3s
>100
3t
>100
4a
25.0 (144.5)
25.0 (130.7)
12.5 (60.2)
25.0 (120.7)
50.0 (240.8)
12.5 (66.7)
25.0 (133.5)
50.0 (267.1)
25.0 (114.6)
25.0 (123.0)
25.0 (123.0)
50.0 (246.0)
50.0 (206.6)
>100
signals from 115.2 to 117.4 and from 117.9 to 127.2 ppm,
corresponding to CHdCH2 moieties.
All of the compounds showed mass spectra with molecular
ions characteristic of their chemical structure.
4b
4c
8s
100.0 (390.5)
>100
9d
9r
4d
4e
25.0 (113.6)
100.0 (340.0)
>100
Following the presented methodology, we synthesized an
extensive set of 4-substituted N-phenyl-1,2,3-triazole derivatives.
Cytotoxicity studies were done only on the most active com-
pounds using the MTT assay. The ratios between cytotoxicity
and tuberculostatic activities in vitro enabled the determination
of the selectivity index (SI). Compounds that exhibited SI values
greater than 10 were considered nontoxic.29 Comparing the
toxicity exhibited by the compounds using the two cell lines,
compounds 4c, 5h, 5g, 5e, and 5f showed lower SI values for the
HepG2 cell line while the remaining compounds showed no
toxicity. In some cases, the selectivity index for these compounds
was higher than 1612. These results demonstrated that only
compound 4c was toxic with an SI value lower than 10.
All of the compounds were evaluated against M. tuberculosis
H37Rv ATCC 27294, and the principal results are reported in
Table 1. The tested compounds showed antimycobacterial
activity with most of their MIC values between 267.1 and
1.8 μM. However, the test compounds 3aꢀs were ineffective at
inhibiting the growth of the M. tuberculosis H37Rv ATCC 27294
strain (MICs g 100 mg/L). It is possible that failure of mycolic
acid synthesis upon cell wall formation in this strain could prevent
penetration of this group of substances into the mycobacteria.
In our previous work,16 we synthesized the derivatives 4cꢀd,
4f, 4iꢀj, 4m, 4r, 9d, and 9r using diazomalonaldehyde, which
was added to aniline hydrochlorides through cycloaddition.
Diazomalonaldehyde was obtained from a relatively complex
four-step synthetic route.16 As expected, the synthesis of 1,2,3-
triazole derivatives using click chemistry proved to be more
effective than using diazomalonaldehyde.
9t
4f
10a
10c
10i
10j
10m
10n
10o
4g
50.0 (243.1)
>100
4h
4i
50.0 (243.5)
>100
4j
4l
>100
4m
4n
3.12 (13.0)
showed the carbonyl peaks at 1651ꢀ1703 cmꢀ1, and the NH
stretching vibrations at 3013ꢀ3213 cmꢀ1. The 1H NMR spectra
displayed the hydrazide (NH) protons as singlets between 12.40
and 11.94 ppm, and the hydrazone protons (HꢀCdNꢀN)
between 8.91 and 8.55 ppm. The 13C NMR spectra showed
CdO signals at 162.0ꢀ163.4 ppm and CdN signals at 142.6ꢀ
143.0 ppm.
The Wittig reaction was used to synthesize the 4-vinyl
compounds (10a, 10c, 10iꢀj, and 10mꢀo).25 Most of the
Wittig reagents used were prepared with ultrasound in situ using
a mixture of the appropriate phosphonium salt and base. In the
work presented, the reaction of the corresponding aldehydes (4a,
4c, 4iꢀj, and 4mꢀo) with methyl(triphenyl1)phosphonium
bromide in the presence of NaH gave only the 4-vinyl-1,2,3-
triazoles (10a, 10c, 10iꢀj, and 10mꢀo). The FTIR spectra
showed CdC peaks at 1485 to 1505 cmꢀ1. The 1H NMR spectra
showed CHdCHH0 protons as doublets from 5.44 to 6.02 and
from 6.76 to 6.80 ppm. The 13C NMR showed characteristic
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Journal of Medicinal Chemistry
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’ CONCLUSIONS
analyses were performed on a Perkin-Elmer 2400 CHN elemental analyzer
(S~ao Paulo University, USP/Brazil) and within 0.4% of theoretical values.
General Procedure for Preparation of 2aꢀo. In a round-bottom
flask equipped with a magnetic stirring bar, substituted aniline was
dissolved (10 mmol) with HCl 6N (10 mL) in an ice bath at 0ꢀ5 ꢀC.
Next, NaNO2 (15 mmol in 25 mL of H2O) was added dropwise. The
reaction mixture was stirred for 30 min at 0ꢀ5 ꢀC. Next, a solution of
sodium azide (40 mmol in 50 mL of H2O) was added dropwise. After
addition, the system was stirred for another hour. Next, the mixture was
extracted with ethyl acetate and the combined organic extracts were
washed with H2O, dried over anhydrous Na2SO4, filtered, and concen-
trated in vacuo. The residual crude product was used directly without
purification.
In summary, this study showed that 1,2,3-triazole derivatives
exhibited antimycobacterial activity in the same range as INH for
the susceptible H37Rv strain. Several synthesized compounds
displayed MIC values below the 6.25 μg/mL value postulated by
the Global Program for the Discovery of New Anti-Tuberculosis
Drugs as an upper threshold for the evaluation of new
M. tuberculosis therapies. We believe that the isonicotinoyl
hydrazide unit in compounds 5aꢀo plays an important role in
its antibacterial activity but is not the only pharmacophore
involved. We observed that phenyl triazoles with various sub-
stituents exhibited notably different activities. Specifically, the
substituent at the 4-position on the triazole was much more
influential on inhibitory activity than other positions. We could
therefore conclude that the reactivity order of compounds having
substituent at the 4-position on the triazole was isonicotinoyl
hydrazide > vinyl > CHO > CHF2 > CF3 . CH2F . COOCH3
. CH2OH. Moreover, it is expected that isonicotinoyl hydrazide
derivatives 5aꢀo could exhibit lower toxicity and fewer side
effects than INH itself because the highly reactive hydrazine
group in INH is protected in the isonicotinoyl hydrazide
derivatives.30 Whereas there are no new options for treating
TB, we envision the possibility of using INH derivatives, such as
the ones reported here, as suitable lead compounds for further
development. The results reported in this study should be useful
in guiding future efforts to discover new compounds with
increased tuberculostatic activity.
General Procedure for Preparation of 3aꢀs. In a round-bottom flask
equipped with a magnetic stirring bar, sodium azide (0.83 mmol) was
added, along with propargyl alcohol (0.75 mmol), tert-butanol (0.7 mL),
CuSO4 pentahydrate (0.04 mmol), sodium ascorbate (0.11 mmol), and
H2O (0.7 mL). The reaction mixture was stirred for 48ꢀ72 h at room
temperature and subsequently extracted with ethyl acetate. The com-
bined organic extracts were washed with H2O, dried over anhydrous
Na2SO4, filtered, and concentrated in vacuo. The residual crude product
was purified via silica gel column chromatography using a gradient
mixture of hexaneꢀethyl acetate to obtain the pure derivatives 3aꢀs.
1-(Phenyl)-1H-1,2,3-triazole-4-yl-methanol (3a). White solid, mp
= 109ꢀ110 ꢀC. IR νmax (cmꢀ1): 3379, 3138, 1594, 1501, 1465, 1349,
1
1238, 1176, 1012, 819, 758, 684. H NMR (DMSO-d6, 300 MHz): δ
4.73 (1H, d, J = 5.6, OH), 5.46 (2H, td, J = 5.6 and 1.7, CH2OH),
7.56ꢀ7.62 (1H, m, H-40), 7.68ꢀ7.73 (2H, m, H-30 and H-50),
8.00ꢀ8.03 (2H, m, H-20 and H-60), 8.77 (1H, s, H-5). 13C NMR
(DMSO-d6, 75 MHz): δ 55.7 (CH2OH), 120.6 (C-40), 121.6 (C-5),
129.1 (C-30 and C-50), 130.5 (C-20and C-60), 137.4 (C-10), 149.8 (C-4).
1-(4-Fluorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3b). White
solid, mp = 133ꢀ134 ꢀC. IR νmax (cmꢀ1): 3397, 3230, 3066, 1575,
1494, 1290, 1250, 1060, 824, 685. 1H NMR (DMSO-d6, 300 MHz): δ
4.90 (2H, d, J = 5.8, CH2OH), 5.50 (1H, t, J = 5.8, OH), 7.72 (2H, d, J =
9.3, H-30 and H-50), 8.03 (2H, d, J = 9.3, H-20 and H-60), 8.80 (1H, s,
H-5). 13C NMR (DMSO-d6, 75 MHz): δ 56.0 (CH2OH), 121.3 (C-5),
121.8 (C-20 and C-60), 130.2 (C-20 and C-60), 141.6 (C-10), 142.4 (C-4),
160.8 (C-40).
The preparation of new compounds (3t, 4e, 4h, 4n, 4o, 5aꢀo,
6p, 7p, 8cꢀd, 8pꢀs, 9t, 10c, 10iꢀj, and 10mꢀo) was performed
with robust yields from commercially available materials. The
synthesis of the new 1,2,3-triazole derivatives described in this
work took advantage of azide and alkyne reactivity in the Huisgen
cycloaddition. The methodology utilized was a simple way to
obtain 4-substituted N-phenyl-1,2,3-triazoles using CuSO4 and
sodium ascorbate. Several of the 1,2,3-triazole derivatives synthe-
sized using this technology exhibited strong activity when
compared with first-line drugs, such as INH and rifampicin.
1-(4-Chlorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3c). White
solid, mp = 144ꢀ145 ꢀC. IR νmax (cmꢀ1): 3320, 3113, 3071, 2930,
2867, 2826, 1500, 1433, 1411, 1239, 1184, 1092, 1061, 1039, 1014, 836,
774, 703, 676. 1H NMR (DMSO-d6, 300 MHz): δ 4.61 (2H, d, J = 5.6,
CH2OH), 5.35 (1H, t, J = 5.6, OH), 7.66 (2H, d, J = 9.1, H-30 and H-50),
7.95 (2H, d, J = 9.1, H-20 and H-60), 8.71 (1H, s, H-5). 13C NMR
(DMSO-d6, 75 MHz): δ 55.0 (CH2OH), 121.1 (C-5), 121.6 (C-20 and
C-60), 129.9 (C-30 and C-50), 132.8 (C-40), 135.6 (C-10), 149.4 (C-4).
1-(3-Chlorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3d). White
solid, mp = 95ꢀ97 ꢀC. IR νmax (cmꢀ1): 3263, 3090, 1593, 1487,
’ EXPERIMENTAL SECTION
1. Chemistry. Reagents were purchased from Aldrich or Acros
Chemical Co. and used without further purification. Column chroma-
tography was performed with Silica Gel 60 (Merck 70ꢀ230 mesh).
Analytical thin-layer chromatography was performed with silica gel
plates (Merck, thin layer chromatography (TLC) Silica Gel 60 F254),
and the spots were visualized using ultraviolet (UV) light or aqueous
solutions of ammonium sulfate. Yields refer to chromatographically and
spectroscopically homogeneous materials. Melting points were obtained
on a FischerꢀJohns apparatus and are uncorrected. Infrared spectra
were measured using potassium bromide (KBr) pellets on a Perkin-
Elmer model 1420 FT-IR spectrophotometer, which was calibrated
relative to the 1601.8 cmꢀ1 absorbance of polystyrene. The NMR spectra
were recorded on a Varian Unity Plus VXR (300 MHz) instrument and
Bruker Avance instruments (400 and 500 MHz) in DMSO-d6, deutero-
chloroform (CDCl3), or acetone-d6 (CD3COCD3) solutions. The
chemical shift data are reported in units of δ (ppm) downfield from
tetramethylsilane (TMS) or the solvent, which was used as an internal
standard. Coupling constants (J) are reported in hertz and refer to
apparent peak multiplicities. Mass spectra were acquired on a Shimadzu
model QP5050A instrument coupled to GC model 17A (Shimadzu).
Elemental analysis was used to ascertain purity > (95%) of all com-
pounds for which biological data were determined. The CHN elemental
1
1464, 1236, 1043, 871, 784, 671. H NMR (DMSO-d6, 300 MHz): δ
4.61 (2H, d, J = 4.7, CH2OH), 5.36 (2H, t, J = 5.5, OH), 7.54ꢀ7.56 (1H,
m, H-40), 7.62 (1H, t, J = 8 Hz, H-50), 7.91ꢀ7.94 (1H, m, H-60),
8.04ꢀ8.06 (1H, m, H-20), 8.77 (1H, s, H-5). 13C NMR (DMSO-d6, 75
MHz): δ 54.9 (CH2OH), 118.4 (C-50), 119.6 (C-40), 121.1 (C-5), 128.2
(C-20), 131.6 (C-60), 134.1 (C-30), 137.7 (C-10), 149.3 (C-4).
1-(2-Chlorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3e). White
solid, mp = 86ꢀ87 ꢀC. IR νmax (cmꢀ1): 3266, 3112, 3072, 2988,
2935, 2868, 1498, 1467, 1420, 1380, 1341, 1227, 1181, 1122, 1041, 1012,
1
947, 882, 765, 675. H NMR (DMSO-d6, 300 MHz): δ 4.62 (2H, d,
J = 5.6, CH2OH), 5.32 (1H, t, J = 5.6, OH), 7.55ꢀ7.67 (3H, m, H-30,
H-40 and H-50), 7.76 (1H, dd, J = 1.95 and 1.22), 8.40 (1H, s, H-5). 13C
NMR (DMSO-d6, 75 MHz): δ 128.4 (C-20), 124.8 (C-5), 131.4 (C-30),
130.5 (C-40), 128.3 (C-50), 128.2 (C-60), 54.8 (C-6), 135.0 (C-10), 148.0
(C-4).
5992
dx.doi.org/10.1021/jm2003624 |J. Med. Chem. 2011, 54, 5988–5999

Journal of Medicinal Chemistry
ARTICLE
1-(4-Methylphenyl)-1H-1,2,3-triazole-4-yl)methanol (3f). White
solid, mp = 124ꢀ125 ꢀC. IR νmax (cmꢀ1): 3426, 3221, 3117, 1517,
1239, 1187, 1042, 1013, 824, 772, 714, 686. 1H NMR (DMSO-d6, 300
MHz): δ 2.28 (3H, s, CH3), 4.66 (2H, d, J = 5.2, CH2OH), 5.48 (1H, s,
OH), 7.65 (2H, d, J = 9.5, H-30 and H-50), 7.99 (2H, d, J = 9.5, H-20 and
H-60), 8.89 (1H, s, H-5). 13C NMR (DMSO-d6, 75 MHz): δ 21.1
(CH3), 59.0 (CH2OH), 120.0 (C-5), 121.6 (C-20 and C-60), 130.9 (C-20
and C-60), 132.7 (C-40), 135.3 (C-10), 150.4 (C-4).
H-20), 8.78 (1H, s, H-5). 13C NMR (DMSO-d6, 75 MHz): δ 55.0
(CH2OH), 120.0 (C-50), 121.3 (C-5), 121.6 (C-20), 130.9 (C-40), 131.8
(C-60), 132.5 (C-30), 136.3 (C-10), 149.6 (C-4).
1-(2,5-Dichlorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3o). White
solid, mp = 114ꢀ116 ꢀC. IR νmax (cmꢀ1): 3283, 3138, 3080, 2934, 1583,
1484, 1452, 1369, 1237, 1094, 1054, 1022, 844, 808. 1H NMR (DMSO-d6,
300 MHz): δ4.62 (2H, s, CH2OH), 5.36 (1H, s, OH), 7.71 (1H, dd, J =8.8
and 2.7, H-40), 7.80 (1H, d, J = 8.8, H-30), 7.86 (1H, d, J = 2.7, H-60), 8.42
(1H, s, H-5). 13C NMR (DMSO-d6, 75 MHz): δ 54.5 (CH2OH), 124.8
(C-5), 127.4 (C-20), 128.0 (C-60), 131.2 (C-40), 131.8(C-30), 132.3 (C-50),
135.5 (C-10), 148.1 (C-4).
1-(3-Methylphenyl)-1H-1,2,3-triazole-4-yl)methanol (3g). White
solid, mp = 94ꢀ95 ꢀC. IR νmax (cmꢀ1): 3257, 3128, 3089, 1611, 1488,
1
1232, 1055, 1017, 851, 786, 688. H NMR (DMSO-d6, 300 MHz):
δ 1.87 (3H, s, CH3), 3.09 (1H, t, J = 4.8, OH), 4.89 (2H, d, J = 4.8,
CH2OH), 7.23ꢀ7.27 (1H, m, H-40), 7.36ꢀ7.41 (1H, m, H-50),
7.47ꢀ7.50 (1H, m, H-60), 7.55ꢀ7.56 (1H, m, H-20), 7.98 (1H, s,
H-5). 13C NMR (DMSO-d6, 75 MHz): δ 21.2 (CH3), 56.0
(CH2OH), 117.4 (C-60), 120.2 (C-5), 121.0 (C-40 and C-50), 129.4
(C-20), 136.7 (C-30), 139.8 (C-10), 148.4 (C-4).
1-(3,5-Dichlorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3p). Brown
solid, mp = 145ꢀ146 ꢀC. IR νmax (cmꢀ1): 3244, 3113, 3074, 2935, 1585,
1474, 1438, 1238, 1060, 1026, 860, 802. 1H NMR (DMSO-d6, 400 MHz):
δ 4.61 (2H, d, J = 5.5 Hz, CH2OH), 5.38 (1H, t, J = 5.5 Hz, OH), 7.74
(1H, s, H-40), 8.07 (2H, d, J=1.5Hz, H-20 and H-60), 8.83(1H, s, H-5). 13C
NMR (DMSO-d6, 100 MHz): δ 54.8 (CH2OH), 118.5 (C-40), 121.3
(C-5), 127.8 (C-20 and C-60), 135.2 (C-30 and C-50), 138.3 (C-10), 149.5
(C-4). Anal. CalcdforC9H7Cl2N3O: C, 44.29; H, 2.89; N, 17.22. Found: C,
44.53; H, 3.08; N, 15.30.
4-(4-(Hydroxymethyl)-1H-1,2,3-triazole-1-yl)benzonitrile (3q). Yellow
solid, mp = 165ꢀ166 ꢀC. IR νmax (cmꢀ1): 3282, 3140, 2615, 2229, 1951,
1824, 1604, 1516, 1365, 1246, 1029, 856, 563. 1H NMR (DMSO-d6, 500
MHz): δ 4.62 (2H, d, J = 5.5 Hz, CH2OH), 5.42 (1H, t, J = 5.5 Hz, OH),
8.10ꢀ8.08 (2H, m, H-30 and H-50), 8.17ꢀ8.15 (2H, m, H-20 and H-60), 8.86
(1H, s, H-5). 13C NMR (DMSO-d6, 125 MHz): δ 54.9 (CH2OH), 110.8
(C-40), 118.2 (CN), 120.2 (C-20 and C-60), 121.2 (C-5), 134.3 (C-30 and
C-50), 139.6 (C-10), 149.7 (C-4).
3-(4-(Hydroxymethyl)-1H-1,2,3-triazole-1-yl)benzonitrile (3r). White
solid, mp = 125.2ꢀ126.3 ꢀC. IR νmax (cmꢀ1): 3286, 3132, 3089, 2881,
2237, 1720, 1585, 1500, 1446, 1246, 1049, 1018, 883. 1H NMR (DMSO-d6,
400 MHz): δ 4.62 (2H, d, J = 5.5 Hz, CH2OH), 5.37 (1H, t, J = 5.5 Hz,
OH), 7.80 (1H, t, J=8.0Hz, H-40), 7.96ꢀ7.94 (1H, m, H-50), 8.29(1H, dd,
J = 1.2 and 8.2 Hz, H-60), 8.44 (1H, s, H-20), 8.79 (1H, s, H-5). 13C NMR
(DMSO-d6, 100 MHz): δ 54.8 (CH2OH), 112.7 (C-40), 117.8 (CN),
121.1 (C-5), 123.2 (C-20), 124.5 (C-60), 131.2 (C-30) 132.0 (C-50), 137.1
(C-10), 149.5 (C-4).
1-(2-Methylphenyl)-1H-1,2,3-triazole-4-yl)methanol (3h). White
solid, mp = 58ꢀ59 ꢀC. IR νmax (cmꢀ1): 3266, 3112, 3072, 2988, 2935,
2868, 1498, 1467, 1420, 1380, 1341, 1227, 1181, 1122, 1041, 1012, 947,
882, 765, 710, 675, 643. 1H NMR (DMSO-d6, 300 MHz): δ 2.24 (3H, s,
CH3), 4.61 (2H, d, J = 5.4, CH2OH), 5.45 (1H, s, OH), 7.37ꢀ7.49 (4H,
m, H-30, H-40, H-50 and H-60), 8.23 (1H, s, H-5). 13C NMR (DMSO-d6,
75 MHz): δ 17.6 (CH3), 55.1 (C-20), 124.6 (C-5), 126.2 (C-30), 127.3
(C-40), 130.0 (C-50), 131.6 (C-60), 133.3 (C-6), 136.6 (C-10), 148.2 (C-4).
1-(4-Nitrophenyl)-1H-1,2,3-triazole-4-yl)methanol (3i). White so-
lid, mp = 201ꢀ202 ꢀC. IR νmax (cmꢀ1): 3283, 3138, 3080, 2934, 1583,
1484, 1452, 1369, 1237, 1094, 1054, 1022, 844, 808. 1H NMR (DMSO-
d6, 300 MHz): δ 4.63 (2H, s, CH2OH), 5.39 (1H, s, OH), 8.23 (1H, d,
J = 9.1, H-20), 8.44 (1H, d, J = 9.1, H-30), 8.23 (1H, d, J = 9.1, H-50), 8.44
(1H, d, J = 9.1, H-60). 13C NMR (DMSO-d6, 75 MHz): δ 54.2
(CH2OH), 120.7 (C-5), 119.7 (C-20), 119.7 (C-60), 140.3 (C-40),
124.9 (C-30), 124.9 (C-50), 145.9 (C-10), 149.2 (C-4).
1-(4-Methoxyphenyl)-1H-1,2,3-triazole-4-yl)methanol (3j). White
solid, mp = 127ꢀ129 ꢀC. IR νmax (cmꢀ1): 3421, 3145, 3093, 1584, 1488,
1400, 1225, 1140, 1061, 703, 676. 1H NMR (DMSO-d6, 300 MHz): δ
4.57 (2H, d, J = 5.5, CH2OH), 5.4 (1H, t, J = 5.5, OH), 7.74 (1H, d, J =
9.1, H-60), 7.09 (1H, d, J = 9.1, H-50), 7.09 (1H, d, J = 9.1, H-30), 7.74
(1H, d, J = 9.1, H-20), 8.45 (1H, s, H-5). 13C NMR (DMSO-d6, 75
MHz): δ 55.1 (CH2OH), 115.1 (C-50), 121.2 (C-5), 121.9 (C-20), 130.3
(C-40), 121.9 (C-60), 115.1 (C-30), 149.0 (C-10), 159.4 (C-4).
1-(3-Methoxyphenyl)-1H-1,2,3-triazole-4-yl)methanol (3l). White
solid, mp = 100ꢀ102 ꢀC. IR νmax (cmꢀ1): 3256, 3110, 3070, 2987, 2930,
2868, 1488, 1447, 1419, 1380, 1351, 1227, 1171, 1112, 1041, 1012, 947,
892, 766, 709, 665, 643. 1H NMR (DMSO-d6, 300 MHz): δ 3.87 (3H, s,
CH3), 4.88 (2H, d, J = 5.7, CH2OH), 2.9 (1H, t, J = 5.7, OH), 7.32 (1H,
dd, J = 2.3 H-20), 6.97 (1H, ddd, J = 8.1, J = 2.3, J = 0.9, H-40), 7.40 (1H,
dd, J = 8.1, H-50), 7.23 (1H, ddd, J = 8.1, J = 2.3, J = 0.9, H-60), 7.97 (1H,
s, H-5). 13C NMR (DMSO-d6, 75 MHz): δ 55.5 (OCH3), 56.1 (CH2),
112.3 (C-40), 114.6 (C-60), 120.2 (C-5), 121.9 (C-20), 130.4 (C-50),
137.9 (C-10), 148.4 (C-4), 160.5 (C-30).
1-(2-Methoxyphenyl)-1H-1,2,3-triazole-4-yl)methanol (3m). White
solid, mp = 116ꢀ117 ꢀC. IR νmax (cmꢀ1): 3276, 3123, 3078, 2954,
1603, 1509, 1472, 1286, 1250, 1180, 1122, 1016, 861, 761, 715, 682. 1H
NMR (DMSO-d6, 300 MHz): δ 3.58 (3H, s, CH3), 4.95 (2H, d, J = 5.4,
CH2OH), 2.82 (1H, t, J = 5.4, OH), 7.40ꢀ7.49 (4H, m, H-30, H-40, H-50
and H-60), 8.15 (1H, s, H-5). 13C NMR (DMSO-d6, 75 MHz): δ 59.8 (C-
20), 59.9 (OCH3), 126.6 (C-5), 127.2 (C-30), 128.3 (C-40), 131.0 (C-50),
131.9 (C-60), 133.8 (C-6), 137.6 (C-10), 150.2 (C-4).
1-(4-Bromophenyl)-1H-1,2,3-triazole-4-yl)methanol (3s). Brown
solid, mp = 134.0ꢀ137.1 ꢀC. IR νmax (cmꢀ1): 3232, 3120, 2927, 2666,
1
1913, 1550, 1500,1404, 1242, 1184, 1060, 1037, 991, 833. H NMR
(DMSO-d6, 500 MHz): δ 4.60 (2H, s, CH2OH), 7.80ꢀ7.78 (2H, m,
H-30 and H-50), 7.89ꢀ7.88 (2H, m, H-20 and H-60), 8.73 (1H, s, H-5).
13C NMR (DMSO-d6, 125 MHz): δ 54.9 (CH2OH), 121.0 (C-5), 121.1
(C-40), 121.8 (C-20 and C-60), 132.8 (C-30 and C-50), 135.9 (C-10),
149.3 (C-4). Anal. Calcd for C9H8BrN3O: C, 42.54; H, 3.17; N, 16.54.
Found: C, 42.33; H, 3.24; N, 16.16.
General Procedure for Preparation of 4aꢀo, 4r. In a round-bottom
flask equipped with a magnetic stirring bar, IBX (11 mmol) and 10 mmol
of general 1,2,3-triazole of type 3 was added to DMSO (27.5 mL) and
stirred at room temperature for 4 h. Then, H2O (20 mL) was added to
precipitate IBX crystals, and these crystals were decanted. The mother
liquor was extracted with ethyl acetate, washed with NaHCO3 solution,
and dried over MgSO4 to obtain pure aldehydes.
1-(Phenyl-1H-1,2,3-triazole-4-carbaldehyde (4a). White solid,
mp = 95ꢀ96 ꢀC. IR νmax (cmꢀ1): 3431, 3131, 1691, 1529, 1209,
1
1168, 990, 853, 782, 761, 683. H NMR (DMSO-d6, 300 MHz): δ
7.50ꢀ7.79 (4H, m, H-20, H-30, H-50 and H-60), 8.54 (1H, s, H-5), 10.23
(1H, s, H-6). 13C NMR (DMSO-d6, 75 MHz): δ 120.8 (C-20 and C-60),
123.1 (C-5), 129.7 (C-40), 130.0 (C-30 and C-50), 136.1 (C-10), 148.0
(C-4), 185.0 (C-6), MS (ESI) m/z 173 (M)+.
1-(3,4-Dichlorophenyl)-1H-1,2,3-triazole-4-yl)methanol (3n). White
solid, mp = 122ꢀ123 ꢀC. IR νmax (cmꢀ1): 3421, 3145, 3093, 1584, 1488,
1-(4-Fluorophenyl)-1H-1,2,3-triazole-4-carbaldehyde (4b). Yellow
solid, mp = 127ꢀ128 ꢀC. IR νmax (cmꢀ1): 3382, 3116, 3046, 1702, 1513,
1231, 1214, 1009, 837, 780, 613. 1H NMR (DMSO-d6, 300 MHz): δ 7.80
(2H, d, J = 9.5, H-30 and H-50), 8.10 (2H, d, J = 9.5, H-20 and H-60),
1
1400, 1225, 1140, 1061, 992, 872, 832, 804. H NMR (DMSO-d6, 300
MHz): δ4.60 (2H, d, J=4.9, CH2OH), 5.37 (1H, t, J= 4.9, OH), 7.86 (1H,
d, J = 8.9, H-60), 7.96 (1H, dd, J = 8.9 and 2.4, H-50), 8.26 (1H, d, J = 2.4,
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Journal of Medicinal Chemistry
ARTICLE
8.85 (1H, s, H-5), 10,20 (1H, s, H-6). 13C NMR (DMSO-d6, 75 MHz):
δ 119.8 (C-20 and C-60), 121.1 (C-5), 129.7 (C-40), 131.0 (C-30 and
C-50), 140.1 (C-10), 150.0 (C-4), 183.0 (C-6). MS (ESI) m/z 191 (M)+.
1-(2-Chlorophenyl)-1H-1,2,3-triazole-4-carbaldehyde (4e). Yellow
solid, mp = 76ꢀ77 ꢀC. IR νmax (cmꢀ1): 3138, 3092, 2860, 1704, 1573,
1529, 1487, 1402, 1371, 1261, 1199, 1170, 1142, 1100, 1075, 1042, 982,
857, 816, 698, 649. 1H NMR (DMSO-d6, 300 MHz): δ 7.52ꢀ7.82 (4H,
m, C-30,C-40,C-50 and C-60), 9.34 (1H, s, H-5), 10.13 (1H, s, CHO). 13C
NMR (DMSO-d6, 75 MHz): δ 131.8 (C-20), 126.6 (C-60), 128.6 (C-5),
126.7 (C-50), 128.7 (C-40), 130.4 (C-30), 126.8 (C-10), 144.9 (C-4), 182.9
(C-6).
1-(3-Methylphenyl)-1H-1,2,3-triazole-4-carbaldehyde (4g). White
solid, mp = 90ꢀ92 ꢀC. IR νmax (cmꢀ1): 3433, 3459, 1457, 1158, 1025,
857, 759. 1H NMR (DMSO-d6, 300 MHz): δ 2.48 (3H, s, CH3),
7.32ꢀ7.61 (4H, m, H-20, H-40, H-50 and H-60), 8.52 (1H, s, H-5),
10.22 (1H, s, H-6). 13C NMR (DMSO-d6, 75 MHz): δ 21.3 (CH3), 117.8
(C-60), 121.4 (C-50), 123.1 (C-5), 129.7 (C-40), 130.4 (C-20), 136.0
(C-10), 140.3 (C-30), 147.9 (C-4), 184.9 (C-6).
(C-20 and C-60), 121.1 (C-5 and C-3 INH ring), 123.3 (C-5), 128.7
(C-40), 130.0 (C-30 and C-50), 136.6 (C-10), 140.0 (CdN), 152.0 (C-2
and C-6 INH ring), 168.0 (CdO). MS (ESI) m/z 292 (M)+. Anal. Calcd
for C15H12N6O: C, 61.64; H, 4.14; N, 28.75. Found: C, 61.47; H, 4.08;
N, 28.68.
(E)-N0-[(1-(4-Fluorophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl hydrazide (5b). White solid, mp = 254ꢀ255 ꢀC. IR νmax
(cmꢀ1): 3454, 3232, 3131, 3080, 1693, 1515, 1284, 1232, 837, 620. 1H
NMR (DMSO-d6, 300 MHz): δ 7.20 (2H, d, J = 9.5, H-30 and H-50),
7.65 (2H, d, J = 9.5, H-20 and H-60), 7.83 (2H, d, J = 8.0, INH ring), 8.60
(1H, s, H-5), 8.77 (1H, s, NdCꢀH), 8.90 (2H, d, J = 8.0, INH ring),
11.23 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ 115.5 (C-20
and C-60), 121.0 (C-5 and C-3 INH ring), 124.3 (C-5), 124.5 (C-30 and
C-50), 132.6 (C-10), 141.0 (CdN), 152.7 (C-2 and C-6 INH ring), 162.0
(C-40), 168.8 (CdO). MS (ESI) m/z 310 (M)+. Anal. Calcd for
C15H11FN6O: C, 58.06; H, 3.57; N, 27.08. Found: C, 58.47; H, 3.99;
N, 28.58.
(E)-N0-[(1-(4-Chlorophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5c). White solid, mp = 267ꢀ269 ꢀC. IR νmax
(cmꢀ1): 3444, 3246, 1693, 1560, 1499, 1280, 1053, 829, 687. 1H NMR
(DMSO-d6, 300 MHz): δ 7.25 (2H, d, J = 9.7, H-30 and H-50), 7.67 (2H,
d, J = 9.7, H-20 and H-60), 7.82 (2H, d, J = 8.1, INH ring), 8.62 (1H, s,
H-5), 8.70 (1H, s, NdCꢀH), 8.91 (2H, d, J = 8.1, INH ring), 11.25 (1H,
1-(2-Methylphenyl)-1H-1,2,3-triazole-4-carbaldehyde (4h). White
solid, mp = 71ꢀ72 ꢀC. IR νmax (cmꢀ1): 3428, 3104, 1691, 1530, 1200,
1
1045, 996, 874, 773. H NMR (DMSO-d6, 300 MHz): δ 2.28 (3H, s,
CH3), 7.42ꢀ7.61 (4H, m, H-20, H-40, H-50 and H-60), 8.55 (1H, s, H-5),
10.18 (1H, s, H-6). 13C NMR (DMSO-d6, 75 MHz): δ 19.8 (CH3), 119.8
(C-60), 121.6 (C-50), 124.1 (C-5), 130.7 (C-40), 130.1 (C-20), 137.0
(C-10), 145.3 (C-30), 146.9 (C-4), 182.9 (C-6).
13
s, NꢀH). C NMR (DMSO-d6, 75 MHz): δ 116.5 (C-20 and C-60),
122.0 (C-5 and C-3 INH ring), 124.9 (C-5), 125.5 (C-30 and C-50),
131.6 (C-10), 141.8 (CdN), 152.8 (C-2 and C-6 INH ring), 160.0 (C-40),
167.0 (CdO). MS (ESI) m/z 326 (M)+. Anal. Calcd for C15H11ClN6O: C,
55.14; H, 3.39; N, 25.72. Found: C, 55.47; H, 3.72; N, 25.63.
1-(3-Methoxyphenyl)-1H-1,2,3-triazole-4-carbaldehyde (4l). White
solid, mp = 106ꢀ107 ꢀC. IR νmax (cmꢀ1): 3427, 3106, 3038, 2998, 1690,
1607, 1503, 1259, 1169, 1042, 845, 773, 677. 1H NMR (DMSO-d6, 300
MHz): δ 3.90 (3H, s, OCH3), 7.88ꢀ7.95 (4H, m, H-20, H-40, H-50 and
H-60), 9.65 (1H, s, H-5), 10.30 (1H, s, H-6). 13C NMR (DMSO-d6, 75
MHz): δ56.8 (CH3), 121.3 (C-20), 122.3 (C-60), 125.0 (C-5), 115.8 (C-50),
148.0 (C-40), 114.8 (C-30), 130.2 (C-10), 160.8 (C-4), 185.8 (C-6).
1-(3,4-Dichlorophenyl)-1H-1,2,3-triazole-4-carbaldehyde (4n).
Yellow solid, mp = 168ꢀ169 ꢀC. IR νmax (cmꢀ1): 3127, 3088, 2924,
2873, 1693, 1531, 1487, 1437, 1404, 1261, 1206, 1172, 1139, 1034, 990,
857, 822, 771. 1H NMR (DMSO-d6, 300 MHz): δ 8.02 (1H, d, J = 8.9,
H-60), 8.14 (1H, dd, J = 8.9 and 2.4, H-50), 8.46 (1H, d, J = 2.7, H-20),
9.73 (1H, s, H-5), 10.23 (1H, s, CHO). 13C NMR (DMSO-d6, 75
MHz): δ 120.9 (C-20), 122.7 (C-60), 125.0 (C-5), 132.0 (C-50), 132.2
(C-40), 132.6 (C-30), 135.6 (C-10), 147.7 (C-4), 183.8 (C-6). MS (ESI)
m/z 241 (M)+.
(E)-N0-[(1-(3-Chlorophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5d). White solid, mp = 206ꢀ207 ꢀC. IR νmax
1
(cmꢀ1): 3399, 3237, 3066, 1617, 1575, 1290, 1060, 790, 751,684. H
NMR (DMSO-d6, 300 MHz): δ 7.40 (1H, dd, J = 8.0 and 7.9, H-50), 7.46
(d, 1H, J = 8.0, H-40), 7.51 (1H, d, J = 7.9, H-60), 7.80 (1H, s, H-20), 7.91
(2H, d, J = 8.1, INH ring), 8.51 (1H, s, H-5), 8.79 (1H, s, NdCꢀH),
8.92 (2H, d, J = 8.1, INH ring), 11.04 (1H, s, NꢀH). 13C NMR (DMSO-
d6, 75 MHz): δ 125.6 (C-20), 127.0 (C-60), 128.4 (C-40), 134.2 (C-50),
134 (C-30), 137.5 (C-10), 123.7 (C-5 and C-3 INH ring), 124.6 (C-5),
141.4 (CdN), 152.2 (C-2 and C-6 INH ring), 142.0 (C-4), 166.7
(CdO). MS (ESI) m/z 326 (M)+. Anal. Calcd for C15H11ClN6O: C,
55.14; H, 3.39; N, 25.72. Found: C, 55.25; H, 3.41; N, 25.79.
(E)-N0-[(1-(2-Chlorophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5e). White solid, mp = 204ꢀ206 ꢀC. IR νmax
(cmꢀ1): 3432, 3300, 3126, 1667, 1560, 1493, 1276, 1052, 848, 762. 1H
NMR (DMSO-d6, 300 MHz): δ 7.41 (1H, dd, J = 8.0 and 7.5, H-40), 7.47
(1H, dd, J = 8.0 and 7.5, H-50), 7.49 (1H, d, J = 7.5, H-30), 7.57 (1H, d, J =
8.0, H-60), 7.81 (2H, d, J = 8.5, INH ring), 8.64 (1H, s, H-5), 8.72 (1H, s,
NdCꢀH), 8.93 (2H, d, J = 8.5, INH ring), 11.31 (1H, s, NꢀH). 13C
NMR (DMSO-d6, 75 MHz): δ 132.2 (C-10 and C-20), 128.9 (C-60),
130.1 (C-50), 130.4 (C-40), 132.3 (C-30), 121.7 (C-5 and C-3 INH ring),
124.8 (C-5), 142.2 (CdN), 152.1 (C-2 and C-6 INH ring), 142.3 (C-4),
166.9 (CdO). MS (ESI) m/z 326 (M)+. Anal. Calcd for C15H11ClN6O:
C, 55.14; H, 3.39; N, 25.72. Found: C, 55.03; H, 3.21; N, 25.63.
(E)-N0-[(1-(4-Methylphenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5f). White solid, mp = 230ꢀ234 ꢀC. IR νmax
(cmꢀ1): 3467, 3218, 3135, 1675, 1563, 1284, 1052, 823, 683. 1H NMR
(DMSO-d6, 300 MHz): δ 2.38 (3H, s, CH3), 7.29 (2H, d, J = 9.3, H-30
and H-50), 7.69 (2H, d, J = 9.3, H-20 and H-60), 7.80 (2H, d, J = 8.0, INH
ring), 8.65 (1H, s, H-5), 8.74 (1H, s, NdCꢀH), 8.88 (2H, d, J = 8.0,
INH ring), 11.00 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ
117.5 (C-20 and C-60), 120.0 (C-5 and C-3 INH ring), 125.3 (C-5),
125.9 (C-30 and C-50), 131.8 (C-10), 142.0 (CdN), 153.8 (C-2 and C-6
INH ring), 164.0 (C-40), 168.0 (CdO). MS (ESI) m/z 306 (M)+. Anal.
Calcd for C16H14N6O: C, 62.74; H, 4.61; N, 27.44. Found: C, 62.56; H,
4.69; N, 27.32.
1-(2,5-Dichlorophenyl)-1H-1,2,3-triazole-4-carbaldehyde (4o).
Yellow solid, mp = 163ꢀ164 ꢀC. IR νmax (cmꢀ1): 3138, 3092, 2860,
1704, 1573, 1529, 1487, 1456, 1402, 1371, 1261, 1199, 1170, 1142, 1100,
1
1075, 1042, 982, 857, 816, 765, 698, 649. H NMR (DMSO-d6, 300
MHz): δ 7.78 (1H, dd, J = 8.7 and 2.4, H-40), 7.85 (1H, d, J = 8.7, H-30),
8.02 (1H, d, J = 2.4, H-60), 9.36 (1H, s, H-5), 10.13 (1H, s, H-6). 13C
NMR (DMSO-d6, 75 MHz): δ 128.1 (C-20), 128.7 (C-60), 130.8 (C-5),
132.2 (C-40), 132.4 (C-30), 132.8 (C-50), 134.9 (C-10), 146.7 (C-4),
184.7 (C-6).
General Procedure for Preparation of 5aꢀo. The isonicotinoyl
hydrazide derivatives 5aꢀo were prepared by the reaction of triazole
(4aꢀo) (1.0 mmol) with INH (1.0 mmol) in ethanol/H2O (10 mL) by
initially dissolving the INH in H2O and adding the respective solution to
a solution of the respective triazole (4aꢀo) in ethanol. After stirring for
1ꢀ3 h at room temperature, the resulting mixture was concentrated
under reduced pressure. The residue was purified by washing with cold
ethanol and ethyl ether to obtain the pure derivatives 5aꢀo.
(E)-N0-[(1-Phenyl-1H-1,2,3-triazole-4-yl)methylene]isonicotinoyl
hydrazide (5a). White solid, mp = 212ꢀ213 ꢀC. IR νmax (cmꢀ1): 3097,
1
3034, 1668, 1493, 1424, 1165, 854, 655. H NMR (DMSO-d6, 300
MHz): δ 7.50ꢀ7.59 (5H, m, H-20, H-30, H-40, H-50 and H-60), 7.82 (2H,
d, J = 8.0), 8.55 (1H, s, H-5), 8.75 (1H, s, NdCꢀH), 8.95 (2H, d, J =
8.0), 12.23 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ 120.5
5994
dx.doi.org/10.1021/jm2003624 |J. Med. Chem. 2011, 54, 5988–5999

Journal of Medicinal Chemistry
ARTICLE
(E)-N0-[(1-(3-Methylphenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5g). White solid, mp = 170ꢀ172 ꢀC. IR νmax
(cmꢀ1): 3386, 3218, 3135, 1686, 1568, 1294, 1051, 852, 777, 685. 1H
NMR (DMSO-d6, 300 MHz): δ 2.30 (s, CH3), 7.23 (d, 1H, J = 8.0,
H-40), 7.34 (1H, dd, J = 8.0 and 7.9, H-50), 7.48 (1H, d, J = 7.9, H-60),
7.50 (1H, s, H-20), 7.93 (2H, d, J = 8.2, INH ring), 8.45 (1H, s, H-5), 8.77
(1H, s, NdCꢀH), 8.90 (2H, d, J = 8.2, INH ring), 11.07 (1H, s, NꢀH).
13C NMR (DMSO-d6, 75 MHz): δ 130.6 (C-20), 127.2 (C-60), 128.2
(C-40), 128.5.2 (C-50), 138.0 (C-30), 128.5 (C-10), 123.6 (C-5 and C-3
INH ring), 124.9 (C-5), 142.4 (CdN), 152.9 (C-2 and C-6 INH ring),
142.7 (C-4), 166.6 (CdO). MS (ESI) m/z 306 (M)+. Anal. Calcd for
C16H14N6O: C, 62.74; H, 4.61; N, 27.44. Found: C, 62.70; H, 4.89 N, 27.43.
(E)-N0-[(1-(2-Methylphenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5h). White solid, mp = 185ꢀ186 ꢀC. IR νmax
(cmꢀ1): 3437, 3281, 3089, 1661, 1550, 1281, 1054, 785, 613. 1H NMR
(DMSO-d6, 300 MHz): δ 1.93 (1H, s, CH3), 7.32 (1H, dd, J = 8.0 and
7.5, H-40), 7.38 (1H, dd, J = 8.0 and 7.5, H-50), 7.47 (1H, d, J = 7.5, H-30),
7.30 (1H, d, J = 8.0, H-60), 7.80 (2H, d, J = 8.4, INH ring), 8.60 (1H, s,
H-5), 8.71 (1H, s, NdCꢀH), 8.90 (2H, d, J = 8.4, INH ring), 12.0 (1H,
s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ 17.3 (CH3), 127.2 (C-10),
140.0 (C-20), 120.2 (C-60), 126.1 (C-50 and C-30), 131.4 (C-40), 122.7
(C-5 and C-3 INH ring), 124.9 (C-5), 142.4 (CdN), 152.5 (C-2 and
C-6 INH ring), 142.0 (C-4), 166.4 (CdO). MS (ESI) m/z 306 (M)+.
Anal. Calcd for C16H14N6O: C, 62.74; H, 4.61; N, 27.44. Found: C,
62.27; H, 4.09; N, 26.99.
IR νmax (cmꢀ1): 3423, 3158, 1675, 1504, 1500, 1297, 1184, 1049, 852,
712, 689. H NMR (DMSO-d6, 300 MHz): δ 3.84 (s, OCH3), 7.00
1
(d, 1H, J = 8.0, H-30), 7.12 (dd, 1H, J = 8.0 and 6.5, H-50), 7.30 (dd,
1H, J = 8.0 and 6.5, H-40), 7.47 (d, 1H, J = 8.0 Hz, H-60), 7.89 (2H, d,
J = 8.0, INH ring), 8.48 (1H, s, H-5), 8.70 (1H, s, NdCꢀH), 8.92
(2H, d, J = 8.0, INH ring), 11.05 (1H, s, NꢀH). 13C NMR (DMSO-d6,
75 MHz): δ 57.9 (CH3), 112.5 (C-50 and C-60), 125.8 (C-30), 122.3
(C-40), 119.9 (C-20), 121.2 (C-5 and C-3 INH ring), 122.9 (C-5), 123.6
(C-50), 129.3 (C-10), 143.8 (CdN), 154.7 (C-2 and C-6 INH ring),
171.2 (CdO). MS (ESI) m/z 322 (M)+. Anal. Calcd for C16H14N6O2:
C, 59.62; H, 4.38; N, 26.07. Found: C, 59.89; H, 4.01; N, 26.16.
(E)-N0-[(1-(3,4-Dichlorophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5n). White solid, mp = 244ꢀ246 ꢀC. IR νmax
(cmꢀ1): 3416, 3229, 3045, 1668, 1559, 1485, 1285, 1037, 819, 751, 683.
1H NMR (DMSO-d6, 300 MHz): δ 7.95 (1H, d, J = 9.0, H-60), 7.99 (1H,
dd, J = 9.0 and 2.0 H-50), 7.82 (2H, d, J = 8.1, INH ring), 8.44 (1H, d, J =
2.0, H-20), 9.65 (1H, s, H-5), 8.73 (1H, s, NdCꢀH), 8.89 (2H, d, J = 8.1,
INH ring), 11.05 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ
119.5 (C-20 and C-60), 122.2 (C-5 and C-3 INH ring), 125.0 (C-5),
130.9 (C-30 and C-50), 135.8 (C-10), 142.5 (CdN), 153.9 (C-2 and C-6
INH ring), 132.7.0 (C-40), 169.1 (CdO). MS (ESI) m/z 360 (M)+.
Anal. Calcd for C15H10Cl2N6O: C, 49.88; H, 2.79; N, 23.27. Found: C,
49.77; H, 2.73; N, 23.28.
(E)-N0-[(1-(2,5-Dichlorophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5o). White solid, mp = 246ꢀ247 ꢀC. IR νmax
(cmꢀ1): 3428, 3289, 3140, 1659, 1485, 1285, 1044, 818, 761, 682. 1H
NMR (DMSO-d6, 300 MHz): δ 7.78 (1H, dd, J = 8.1 and 1.9, H-40), 7.80
(1H, d, J = 8.1, H-30), 7.89 (2H, d, J = 8.3, INH ring), 8.01 (1H, d, J = 1.9,
H-60), 8.46 (1H, s, H-5), 8.79 (1H, s, NdCꢀH), 8.91 (2H, d, J = 8.3,
INH ring), 12.08 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ
129.7 (C-20), 129.9 (C-60), 121.2 (C-5 and C-3 INH ring), 130.6 (C-5),
132.2 (C-40), 132.9 (C-30), 133.0 (C-50), 133.8 (C-10), 143.7 (CdN),
154.1 (C-2 and C-6 INH ring), 146,2 (C-4), 185.2 (CdO). MS (ESI)
m/z 360 (M)+. Anal. Calcd for C15H10Cl2N6O: C, 49.88; H, 2.79; N,
23.27. Found: C, 49.53; H, 2.11; N, 23.26.
(E)-N0-[(1-(4-Nitrophenyl)-1H-1,2,3-triazole-4-yl)methylene]-
isonicotinoyl Hydrazide (5i). White solid, mp = 230ꢀ232 ꢀC. IR νmax
(cmꢀ1): 3437, 3299, 3092, 1662, 1584, 1525, 1345, 1276, 1049, 853,
749. 1H NMR (DMSO-d6, 300 MHz): δ 7.35 (2H, d, J = 9.7, H-30 and
H-50), 7.75 (2H, d, J = 9.7, H-20 and H-60), 7.81 (2H, d, J = 8.2, INH
ring), 8.67 (1H, s, H-5), 8.75 (1H, s, NdCꢀH), 8.89 (2H, d, J = 8.2,
INH ring), 12.00 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ
119.5 (C-20), 120.0 (C-60), 121.2 (C-5 and C-3 INH ring), 126.6 (C-5),
125.9 (C-30), 130.0 (C-50), 132.8 (C-10), 142.6 (CdN), 153.0 (C-2 and
C-6 INH ring), 163.0 (C-40), 169.2 (CdO). MS (ESI) m/z 337 (M)+.
Anal. Calcd for C15H11N7O3: C, 53.41; H, 3.29; N, 29.07. Found: C,
53.56; H, 3.19; N, 29.09.
Procedure for Preparation of 6p. In a round-bottom flask equipped
with a magnetic stirring bar, sodium azide (7.5 mmol), methyl propiolate
(11.2 mmol), tert-butanol (5 mL), CuSO4 pentahydrate (0.075 mmol),
sodium ascorbate (0.75 mmol), and H2O (5 mL) were added. The resulting
mixture was stirred for 24 h at room temperature. Next, the mixture was
extracted with CH2Cl2, and the combined organic extracts were washed
with H2O, dried over anhydrous Na2SO4, filtered, and concentrated in
vacuo. The residual crude product was purified via silica gel column chroma-
tography using a gradient mixture of CHCl3ꢀCH3OH to obtain pure 6p.
Methyl 1-(3,5-Dichlorophenyl)-1H-1,2,3-triazole-4-carboxylate (6p).
White solid, mp = 188.1ꢀ190.4 ꢀC. IR νmax (cmꢀ1): 3132, 3105, 3086,
1708, 1589, 1546, 1481, 1438, 1400, 1342, 1276, 1195, 1161, 1037, 875,
852, 817, 775. 1H NMR (DMSO-d6, 400 MHz): δ 3.90 (3H, s, OCH3),
7.81 (1H, t, J = 3.6 Hz, H-40), 8.15 (2H, d, J = 1.8 Hz, H-20 and H-60),
(E)-N0-[(1-(4-Methoxyphenyl)-1H-1,2,3-triazole-4yl)methylene]-
isonicotinoyl Hydrazide (5j). White solid, mp = 235ꢀ236 ꢀC. IR νmax
(cmꢀ1): 3435, 3298, 3088, 1662, 1517, 1277, 1251, 1037, 832, 758. 1H
NMR (DMSO-d6, 300 MHz): δ 7.10 (2H, d, J = 9.1, H-30 and H-50),
7.77 (2H, d, J = 9.1, H-20 and H-60), 7.88 (2H, d, J = 8.4, INH ring), 8.45
(1H, s, H-5), 8.77 (1H, s, NdCꢀH), 8.90 (2H, d, J = 8.4, INH ring),
12.05 (1H, s, NꢀH). 13C NMR (DMSO-d6, 75 MHz): δ 119.7 (C-20),
121.4 (C-60), 120.2 (C-5 and C-3 INH ring), 122.6 (C-5), 114.9 (C-30),
115.0 (C-50), 148.8 (C-10), 143.6 (CdN), 154.0 (C-2 and C-6 INH
ring), 130,2 (C-40), 170.2 (CdO). MS (ESI) m/z 322 (M)+. Anal. Calcd
for C16H14N6O2: C, 59.62; H, 4.38; N, 26.07. Found: C, 59.31; H, 4.39;
N, 25.95.
13
(E)-N0-[(1-(3-Methoxyphenyl)-1H-1,2,3-triazole-4yl)methylene]-
isonicotinoyl Hydrazide (5l). White solid, mp = 190ꢀ192 ꢀC. IR νmax
(cmꢀ1): 3421, 3258, 1670, 1574, 1501, 1295, 1166, 1047, 844, 688.
1H NMR (DMSO-d6, 300 MHz): δ 3.85 (s, OCH3), 6.93 (s, 1H, H-20),
7.11 (1H, d, J = 8.1, H-40), 7.18 (1H, d, J = 7.5, H-60), 7.34 (1H, dd, J =
8.1 and 7.5, H-50), 7.90 (2H, d, J = 8.0, INH ring), 8.42 (1H, s, H-5), 8.76
(1H, s, NdCꢀH), 8.92 (2H, d, J = 8.0, INH ring), 11.05 (1H, s, NꢀH).
13C NMR (DMSO-d6, 75 MHz): δ 55.8 (OCH3), 107.6 (C-20), 121.2
(C-60), 114.2 (C-40), 145.5.2 (C-50), 168.0 (C-30), 128.7 (C-10), 123.7
(C-5 and C-3 INH ring), 125.0 (C-5), 142.7 (CdN), 152.2 (C-2 and
C-6 INH ring), 142.4 (C-4), 165.6 (CdO). MS (ESI) m/z 322 (M)+.
Anal. Calcd for C16H14N6O2: C, 59.62; H, 4.38; N, 26.07. Found: C,
59.69; H, 4.38; N, 26.10.
9.62 (1H, s, H-5). C NMR (DMSO-d6, 100 MHz): δ 119.3 (C-40),
127.8 (C-5), 128.6 (C-20 and C-60), 135.2 (C-30 and C-50), 137.6 (C-10),
139.6 (C-4), 160.2 (CdO). MS (ESI) m/z 272 (M)+. Anal. Calcd for
C10H7Cl2N3O2: C, 44.14; H, 2.59; N, 15.44. Found: C, 44.07; H, 2.64;
N, 15.17.
Procedure for Preparation of 7p. In a round-bottom flask equipped
with a magnetic stirring bar, sodium azide (7.5 mmol), 3,3,3-trifluoro-1-
propyne (11.2 mmol), tert-butanol (5 mL), CuSO4 pentahydrate (0.075
mmol), sodium ascorbate (0.75 mmol), and H2O (5 mL) were added.
Next, the reaction mixture was stirred for 4 days at room temperature,
the mixture was extracted with CH2Cl2, and the combined organic
extracts were washed with H2O, dried over anhydrous Na2SO4, filtered,
and concentrated in vacuo. The residual crude product was purified via
silica gel column chromatography using a gradient mixture of CHCl3ꢀ
CH3OH to obtain pure 7p.
(E)-N0-[(1-(2-Methoxyphenyl)-1H-1,2,3-triazole-4yl)methylene]-
isonicotinoyl Hydrazide (5m). White solid, mp = 194ꢀ195 ꢀC.
5995
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1-(3,5-Dichlorophenyl)-4-(trifluoromethyl)-1H-1,2-triazole (7p).
Yellow oil. IR νmax (cmꢀ1): 3097, 2931, 2357, 2330, 1743, 1585,
1570, 1477, 1442, 1396, 1373, 1261, 1145, 1045, 1026, 983, 856, 790,
740, 725. 1H NMR (DMSO-d6, 400 MHz): δ 7.86 (1H, t, J = 1.6 Hz,
H-40), 8.13 (2H, d, J = 1.6 Hz, H-20 and H-60), 9.69 (1H, s, H-5). 13C
NMR (DMSO-d6, 100 MHz): δ 119.7 (C-40), 120.4 (q, J = 267 Hz,
CF3), 124.9 (d, J = 2.5 Hz, C-5), 129.0 (C-20 and C-60), 135.2 (C-30 and
C-50), 137.4 (C-10), 137.6 (q, J = 115.1 Hz, C-4). 19F NMR (DMSO-d6,
376 MHz): δ ꢀ59.9. MS (ESI) m/z 281 (M)+. Anal. Calcd for
C9H4Cl2F3N3: C, 38.33; H, 1.43; N, 14.90. Found: C, 38.52; H, 1.63;
N, 14.32.
1589, 1562, 1500, 1489, 1381, 1350, 1257, 1230, 1049, 1006, 975, 948,
833, 794, 678. 1H NMR (acetone-d6, 400 MHz): δ 5.58 (2H, d, J = 48.4
Hz, CH2F), 7.87 (1H, t, J = 8.0 Hz, H-40), 7.94 (1H, dt, J = 1.2, 2.5, and
7.7 Hz H-60), 8.31 (1H, ddd, J = 1.1, 2.2, and 8.2 Hz, H-20), 8.37 (1H, t,
J = 1.6 Hz, H-50), 8.88 (1H, d, J = 3.0 Hz, H-5). 13C NMR (acetone-d6,
100 MHz): δ 76.1 (d, J = 161.1 Hz, CH2F), 114.6 (C-40), 118.2
(CN), 124.1 (C-5), 124.6 (C-20), 125.7 (C-60), 132.1 (C-30), 133.1
(C-50), 138.5 (C-10), 144.8 (d, J = 20.4 Hz, C-4). 19F NMR (acetone-
d6, 376 MHz): δ ꢀ206.8. MS (ESI) m/z 202 (M)+. Anal. Calcd for
C10H7FN4: C, 59.40; H, 3.49; N, 27.71. Found: C, 58.97; H, 3.52;
N, 26.50.
Procedure for Preparation of 8cꢀd, 8pꢀs. In a round-bottom flask
equipped with a drying tube, alcohol derivative (1 mmol), DAST
(1 mmol), and CH2Cl2 (20 mL) were mixed. The reaction mixture
was stirred for 1ꢀ4 days at room temperature and was washed with
water, dried over anhydrous Na2SO4, filtered, and concentrated in
vacuo. The residual crude product was purified via silica gel column
chromatography using a gradient mixture of CHCl3ꢀCH3OH to obtain
the pure derivatives 8cꢀd, 8pꢀs.
(1-(4-Bromophenyl)-4-(fluoromethyl)-1H-1,2,3-triazole (8s). White
solid, mp = 168ꢀ171 ꢀC. IR νmax (cmꢀ1): 3124, 3089, 2970, 1558, 1500,
1
1377, 1234, 1026, 964, 825, 767, 690, 513. H NMR (acetone-d6, 400
MHz): δ 5.55 (2H, d, J = 48.4 Hz, CH2F), 7.80 (2H, dt, J = 2.4, 4.8, and
9.4 Hz, H-30 and H-50), 7.90 (2H, dt, J = 2.8, 4.8, and 9.6 Hz, H-20 and
H-60), 8.77 (1H, d, J = 3.2 Hz, H-5). 13C NMR (acetone-d6, 100 MHz): δ
76.1 (d, J = 160.4 Hz, CH2F), 122.6 (C-5), 122.7 (C-40), 123.1 (C-20 and
C-60), 123.9 (d, 2.75 Hz, CH2F), 133.7 (C-30 and C-50), 137.1 (C-10),
144.6 (d, J = 20.4 Hz, C-4). 19F NMR (acetone-d6, 376 MHz): δ ꢀ206.2.
MS (ESI) m/z 256 (M)+. Anal. Calcd for C9H7BrFN3: C, 42.21; H, 2.76;
N, 16.41 Found: C, 42.50; H, 2.99; N, 15.72.
Procedure for Preparation of 9d and 9r. In a round-bottom flask
equipped with a drying tube, alcohol derivative (1 mmol), DAST
(10 mmol), and CH2Cl2 (20 mL) were mixed. The reaction mixture
was stirred for 24 h at room temperature and washed with water, dried
over anhydrous Na2SO4, filtered, and concentrated in vacuo. The
residual crude product was purified via silica gel column chromatogra-
phy using a gradient mixture of CHCl3ꢀCH3OH to obtain the pure
derivatives 9d and 9r.
Procedure for Preparation of 3t and 9t. In a round-bottom flask
equipped with a condenser, cyano derivative (3r and 9r) (1 mmol) and
thiosemicarbazone (1 mmol) were dissolved in CF3COOH (5 mmol).
The reaction mixture was stirred for 24 h at 60 ꢀC and cooled in an ice
bath and adjusted to pH 7ꢀ8 with NH4OH. Precipitate was removed by
vacuum filtration and washed with H2O. The residual crude product was
purified via silica gel column chromatography using a gradient mixture of
CHCl3ꢀCH3OH to obtain the pure derivatives 3t and 9t.
1-(4-Chlorophenyl)-4-(fluoromethyl)-1H-1,2,3-triazole (8c). White
solid, mp = 154.4ꢀ156.3 ꢀC. IR νmax (cmꢀ1): 3128, 3089, 2966, 2927,
1732, 1500, 1238, 1026, 968, 829. 1H NMR (acetone-d6, 400 MHz): δ
5.55 (2H, d, J = 48.8 Hz, CH2F), 7.65 (2H, d, J = 8.8 Hz, H-30 and H-50),
7.95 (2H, d, J = 8.4 Hz, H-20 and H-60), 8.77 (1H, d, J = 2.8 Hz, H-5). 13C
NMR (acetone-d6, 100 MHz): δ 76.2 (d, J = 162.3 Hz, CH2F), 122.9
(C-20and C-60), 124.0 (C-5), 130.8 (C-30 and C-50), 134.8 (C-10), 136.8
(C-40), 144.6 (d, J = 20.4 Hz, C-4). 19F NMR (acetone-d6, 376 MHz):
δ ꢀ206.2. MS (ESI) m/z 211 (M)+. Anal. Calcd for C9H7ClFN3: C,
51.08; H, 3.33; N, 19.86 Found: C, 51.46; H, 3.36; N, 19.34.
1-(3-Chlorophenyl)-4-(fluoromethyl)-1H-1,2,3-triazole (8d). Brown
solid, mp = 95.0ꢀ96.0 ꢀC. IR νmax (cmꢀ1): 3140, 3089, 3059, 2978, 2449,
1955, 1882, 1732, 1597, 1554, 1498,1438, 1226, 1103, 1037, 968, 786. 1H
NMR (acetone-d6, 400 MHz): δ 5.56 (2H, d, J = 48.8 Hz, CH2F), 7.54
(1H, d, J = 8.0 Hz, H-60), 7.64 (1H, t, J = 8.0 Hz, H-50), 7.91 (1H, d, J = 8.0
Hz, H-40), 7.99 (1H, s, H-20), 8.82 (1H, d, J = 3.2 Hz, H-5). 13C NMR
(acetone-d6, 100 MHz): δ 76.2 (d, J = 161.5 Hz, CH2F), 119.8 (C-50),
121.3(C-40), 124.1 (d, J = 3.0 Hz, C-5), 129.6 (C-20), 132.3 (C-60), 135.8
(C-30), 139.0 (C-10), 144.7 (d, J = 20.5 Hz, C-4). 19F NMR (acetone-d6,
376 MHz): δ ꢀ206.3. MS (ESI) m/z 211 (M)+. Anal. Calcd for
C9H7ClFN3: C, 51.08; H, 3.33; N, 19.86 Found: C, 51.08; H, 3.39;
N, 19.20.
(1-(3-(5-Amino-1,3,4-thiadiazol-2-yl)phenyl)-1H-1,2,3-triazole-4-
yl)methanol (3t). Yellow solid, mp = 150.1ꢀ152.0 ꢀC. IR νmax (cmꢀ1):
3441, 3263, 3101, 2727, 2623, 1647, 1519, 1056, 1029, 1010, 821, 794.
1H NMR (DMSO-d6, 400 MHz): δ 4.63 (2H, d, J = 5.5 Hz, CH2OH),
5.36 (1H, t, J = 5.5 Hz, OH), 7.56 (2H, s, NH2) 7.68 (1H, t, J = 8.0 Hz,
H-40), 7.84 (1H, d, J = 7.9 Hz, H-30), 7.97 (1H, dd, J = 1.2 and 8.0 Hz,
H-60), 8.25 (1H, s, H-20), 8.84 (1H, s, H-5). 13C NMR (DMSO-d6, 100
MHz): δ 54.9 (CH2), 117.0 (C-5), 120.6 (C-20 and C-40), 121.2 (C-10),
126.1 (C-50), 130.8 (C-60), 132.5 (C-30), 137.2 (C-4), 149.2 (C-300). MS
(ESI) m/z 274 (M)+. Anal. Calcd for C11H10N6OS: C, 48.17; H, 3.67;
N, 30.64. Found: C, 48.92; H, 3.35; N, 30.17.
5-(3-(4-(Difluoromethyl)-1H-1,2,3-triazole-1-yl)phenyl)-1,3,4-
thiadiazol-2-amine (9t). White solid, mp = 131.0ꢀ132.3 ꢀC. IR νmax
(cmꢀ1): 3383, 3305, 3109, 1678, 1662, 1643, 1508,1411, 1357, 1248,
1188, 1103, 1041, 802. 1H NMR (acetone-d6, 400 MHz): δ 4.57 (2H, bs,
NH2), 7.18 (1H, t, J = 54.4 Hz, CHF2), 7.73 (1H, t, J = 8.0 Hz, H-50),
7.93 (1H, d, J = 6.8 Hz, H-60), 8.04 (1H, d, J = 7.9 Hz, H-40), 8.35 (1H, s,
H-5), 9.10 (1H, s, H-20). 13C NMR (acetone-d6, 100 MHz): δ 111.3 (t,
J = 234.0 Hz, CHF2), 119.1 (C-5), 122.5 (C-20), 123.1 (C-40), 128.0
(C-10), 131.7 (C-50), 134.1 (C-60), 138.3 (C-30), 144.1 (C-4, t, J =
28 Hz), 157.0 (C-NH2), 170.0 (C-300). 19F NMR (acetone-d6, 376 MHz):
δ ꢀ113.6. MS (ESI) m/z 294 (M)+. Anal. Calcd for C11H8F2N6S: C,
44.89; H, 2.74; N, 28.56. Found: C, 44.74; H, 3.02; N, 28.51.
1-(3,5-Dichlorophenyl)4-(fluoromethyl)-1H-1,2,3-triazole (8p).
White solid, mp = 112ꢀ114 ꢀC. IR νmax (cmꢀ1): 3126, 3086, 2976,
1
1587, 1475, 1438, 1390, 1228, 1116, 983, 850. H NMR (acetone-d6,
400 MHz): δ 5.59 (2H, d, J = 48.4 Hz, CH2F), 7.64 (1H, s, H-40), 8.01
(2H, s, H-20and H-60), 8.89 (1H, d, J = 2.8 Hz, H-5). 13C NMR (acetone-
d6, 100 MHz): δ 75.6 (d, J = 162.3 Hz, CH2F), 120.0 (C-40), 124.2
(C-5), 129.2 (C-20and C-60), 136.8 (C-30 and C-50), 139.6 (C-10), 144.9
(d, J = 21.0 Hz, C-4). 19F NMR (acetone-d6, 376 MHz): δ ꢀ207.0. MS
(ESI) m/z 246 (M)+. Anal. Calcd for C9H7Cl2FN3: C, 43.93; H, 2.46; N,
17.08 Found: C, 43.77; H, 2.49; N, 16.24.
4-(4-(Fluoromethyl)-1H-1,2,3-triazole-1-yl)benzonitrile (8q). White
solid, mp = 145ꢀ147 ꢀC. IR νmax (cmꢀ1): 3132, 3089, 2974, 2924, 2229,
1708, 1608, 1566, 1516, 1373, 1242, 1056, 1018, 979, 844, 759. 1H NMR
(acetone-d6, 400 MHz): δ 5.58 (2H, d, J = 48.8 Hz, CH2F), 8.05 (2H, d,
J = 8.8 Hz, H-30 and H-50), 8.18 (2H, d, J = 8.8 Hz, H-20 and H-60), 8.90
(1H, d, J = 2.8 Hz, H-5). 13C NMR (acetone-d6, 100 MHz): δ 76.1 (d, J =
162.1 Hz, CH2F), 113.1 (C-40), 118.5 (CN), 121.8 (C-20and C-60), 124.1
(d, J = 3.8 Hz, C-5), 135.0 (C-30 and C-50), 140.8 (C-10), 145.0(d, J = 20.4
Hz, C-4). 19F NMR (acetone-d6, 376 MHz): δ ꢀ206.9. MS (ESI) m/z
202 (M)+. Anal. Calcd for C10H7FN4: C, 59.40; H, 3.49; N, 27.71. Found:
C, 59.34; H, 3.76; N, 26.05.
General Procedure for Preparation of 10a, 10c, 10iꢀj, 10mꢀo. In
a suspension of anhydrous THF (50 mL) and NaH (2.0 equiv),
methyltriphenylphosphonium bromide (7.42 mmol) under argon was
(4-(Fluoromethyl)-1H-1,2,3-triazole-1-yl)benzonitrile (8r). White
solid, mp = 112.5ꢀ112.9 ꢀC. IR νmax (cmꢀ1): 3140, 3097, 2233, 1732,
5996
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added. The mixture was stirred for 15 min in an ultrasound bath,
acquiring a yellow color. The agitation was maintained for 2 h at room
temperature, and triazole aldehyde (1.45 mmol) was subsequently added.
After 1ꢀ2 h, the reaction mixture was dropped to freeze distilled H2O.
Next, this mixture was extracted with ethyl acetate (3 ꢁ 50 mL). The
combined organic phases were washed with distilled H2O (2 ꢁ 50 mL)
and dried with anhydrous Na2SO4. The crude product was purified by
flash column chromatography using a gradient mixture of hexane-ethyl
acetate.
1-Phenyl-4-vinyl-1H-1,2,3-triazole (10a). Yield 68%, white solid,
mp = 81ꢀ85 ꢀC. IR νmax (cmꢀ1): 3430, 3134, 1502, 1235, 1045, 997,
927, 759, 679. 1H NMR (CDCl3, 500 MHz): δ δ 5.42 (1H, dd, J = 11.0
and 1.2, ꢀCHdCHH0), 6.02 (1H, dd, J = 17.8 and 1.2, ꢀCHdCHH0),
6.80 (1H, dd, J = 17.6 and 11.0, ꢀCHdCHH0), 7.41ꢀ7.75 (5H, m,
H-20, H-30, H-40, H-50, H-60), 7.95 (1H, s, H-5). 13C NMR (CDCl3, 125
MHz): δ 117.1 (ꢀCHdCHH0), 118.6 (ꢀCHdCHH0), 120.8 (C-20 e
C-60), 125.6 (C-5), 129.1 (C-30 e C-50), 130.1 (C-40), 137.3 (C-10),
147.3 (C-4). MS (ESI) m/z 172 (M)+.
1-(4-Chlorophenyl)-4-vinyl-1H-1,2,3-triazole (10c). Yield 99%,
white solid, mp = 85ꢀ91 ꢀC. IR νmax (cmꢀ1): 3121, 1498, 1237,
1092, 1025, 986, 913, 830. 1H NMR (CDCl3, 500 MHz): δ 5.44 (1H,
dd, J = 11.2 and 1.2 Hz, ꢀCHdCHH0), 6.02 (1H, dd, J = 17.8 and 1.2
Hz, ꢀCHdCHH0), 6.78 (1H, dd, J = 17.8 and 11.2 Hz, ꢀCHdCHH0),
7.48ꢀ7.52 (2H, m, H-30 and H-50), 7.67ꢀ7.72 (2H, m, H-20 and H-60),
7.92 (1H, s, H-5). 13C NMR (CDCl3, 125 MHz): δ 116.9
(ꢀCHdCHH0), 117.9 (ꢀCHdCHH0), 121.4 (C-20 and C-60), 124.9
(C-5), 129.7 (C-30 and C-50), 134.3 (C-40), 135.3 (C-10), 147.0 (C-4).
MS (ESI) m/z 206 (M)+. Anal. Calcd for C10H8ClN3: C, 58.41; H, 3.92;
N, 20.43. Found: C, 58.71; H, 4.11; N, 20.28. HRMS (ESMS) calcd for
C10H9ClN3 [M + H]+, 206.0479; found, 206.0531.
1-(4-Nitrophenyl)-4-vinyl-1H-1,2,3-triazole (10i). Yield 60%, yellow
solid, mp = 172ꢀ177 ꢀC. IR νmax (cmꢀ1): 3102, 3083, 2989, 2945, 2879,
1493, 1184, 1129, 1039, 1010, 947, 872, 759, 710, 680, 653, 758, 711, 670.
1H NMR (CDCl3, 500 MHz): δ 5.44 (1H, dd, J = 11.2 and 1.5 Hz,
ꢀCHdCHH0), 5.99 (1H, dd, J = 17.8 and 1.5 Hz, CHdCHH0), 6.77
(1H, dd, J =11.2 and 17.8 Hz, ꢀCHdCHH0), 8.14ꢀ8.19 (2H, m, H-20
and H-60), 8.40ꢀ8.45 (2H, m, H-30 and H-50), 9.02 (1H, s, H-5). 13C
NMR (CDCl3, 125 MHz): δ 115.2 (ꢀCHdCHH0), 118.2 (ꢀCHd
CHH0), 118.4 (C-20 and C-60), 123.0 (C-5), 123.5 (C-30 and C-50), 144.5
(C-40), 138.6 (C-10), 144.6 (C-4). MS (ESI) m/z 217 (M)+. Anal. Calcd
for C10H8N4O2: C, 55.55; H, 3.73; N, 25.91. Found: C, 56.87; H, 4.20; N,
24.59. HRMS (ESMS) calcd for C10H9N4O2 [M + H]+, 217.0720; found,
217.0726.
1-(4-Methoxyphenyl)-4-vinyl-1H-1,2,3-triazole (10j). Yield 71%.
white solid. mp = 72ꢀ76 ꢀC. IR νmax (cmꢀ1): 3102, 3092, 2978,
2935, 2868, 1498, 1191, 1122, 1041, 1012, 947, 882, 765, 710, 675, 643,
748, 715, 670. 1H NMR (CDCl3, 500 MHz): δ 3.93 (3H, s, OCH3), 5.45
(1H, dd, J = 11.2 and 1.5 Hz, ꢀCHdCHH0), 5.98 (1H, dd, J = 17.8 and
1.5 Hz, CHdCHH0), 6.76 (1H, dd, J = 11.2 and 17.8 Hz, ꢀCHd
CHH0), 9.17 (1H, d, J = 9.3 Hz, H-20 and H-60), 8.52 (1H, d, J = 9.0 Hz,
H-30 and H-50), 10.1 (1H, s, H-5). 13C NMR (CDCl3, 125 MHz): δ 55.8
(OCH3), 114.8 (C-30 and C-50), 116.3 (ꢀCHdCHH0), 119.9 (ꢀCHd
CHH0), 121.7 (C-20 and C-60), 125.6 (C-5), 129.9 (C-10), 146.1 (C-40),
159.3 (C-4). MS (ESI) m/z 202 (M)+. Anal. Calcd for C11H11N3O: C,
65.66; H, 5.51; N, 20.88. Found: C, 65.58; H, 5.79; N, 20.77. HRMS
(ESMS) calcd for C11H12N3O [M + H]+, 202.0975; found, 202.0968.
1-(2-Methoxyphenyl)-4-vinyl-1H-1,2,3-triazole (10m). Yield 75%,
white solid, mp = 72ꢀ73 ꢀC. IR νmax (cmꢀ1): 3128, 1601, 1505, 1469,
1289, 1247, 1048, 1013, 908, 748, 695. 1H NMR (CDCl3, 500 MHz): δ
3.89 (3H, s, OCH3), 5.36ꢀ5.40 (1H, m, ꢀCHdCHH0), 5.95ꢀ6.02
(1H, m, ꢀCHdCHH0), 6.75ꢀ6.85 (1H, m, ꢀCHdCHH0), 7.07ꢀ7.79
(4H, m, Ar), 8.06 (1H, s, H-5). 13C NMR (CDCl3, 125 MHz): δ 55.9
(OCH3), 112.2 (C-50), 115.9 (ꢀCHdCHH0), 121.2 (C-60), 122.4
(C-5), 125.4 (ꢀCHdCHH0), 125.9 (C-30), 126.2 (C-10), 130.0 (C-40),
145.7 (C-20), 151.1 (C-4). MS (ESI) m/z 202 (M)+. Anal. Calcd for
C11H11N3O: C, 65.66; H, 5.51; N, 20.88. Found: C, 65.87; H, 5.60;
N, 20.79.
1-(3,4-Dichlorophenyl)-4-vinyl-1H-1,2,3-triazole (10n). Yield 75%,
white solid, mp = 130ꢀ131 ꢀC. IR νmax (cmꢀ1): 3133, 1485, 1437, 1237,
1
1031, 988, 917, 879, 812, 676. H NMR (CDCl3, 500 MHz): δ 5.45
(1H, dd, J = 11.2 and 1.2 Hz, ꢀCHdCHH0), 6.03 (1H, dd, J = 17.7 and
1.2 Hz, ꢀCHdCHH0), 6.77 (1H, dd, J = 11.2 and 17.8 Hz,
ꢀCHdCHH0), 7.61ꢀ7.62 (2H, m, H-50 and H-60), 7.89ꢀ7.90 (1H,
m, H-20), 7.92 (1H, s, H-5). 13C NMR (CDCl3, 125 MHz): δ 117.4
(ꢀCHdCHH0), 117.9 (ꢀCHdCHH0), 119.3 (C-20), 122.0 (C-60),
124.8 (C-5), 131.4 (C-50), 132.8 (C-40), 134.0 (C-30), 135.9 (C-20),
147.3 (C-4). MS (ESI) m/z 240 (M)+. Anal. Calcd for C10H7Cl2N3: C,
50.03; H, 2.94; N, 17.50. Found: C, 51.01; H, 3.36; N, 16.97.
1-(2,5-Dichlorophenyl)-4-vinyl-1H-1,2,3-triazole (10o). Yield 75%,
white solid, mp = 56ꢀ57 ꢀC. IR νmax (cmꢀ1): 3098, 1582, 1483, 1449,
1245, 1097, 1016, 985, 922, 867, 809. 1H NMR (CDCl3, 500 MHz): δ
5.44 (1H, dd, J = 11.2 and 1.2 Hz, ꢀCHdCHH0), 6,04 (1H, dd, J = 17.8
and 1.2 Hz, ꢀCHdCHH0), 6.79 (1H, dd, J = 11.2 and 17.8 Hz,
ꢀCHdCHH0), 7.43 (1H, dd, J = 8.5 and 2.4 Hz, H-30), 7.52 (1H, d, J =
8.5 Hz, H-40), 7.68 (1H, d, J = 2.4 Hz, H-60), 7.97 (1H, s, H-5). 13C NMR
(CDCl3, 125 MHz): δ 116.7 (ꢀCHdCHH0), 121.5 (C-5), 124.4
(C-60), 126.2 (C-50), 127.2 (ꢀCHdCHH0), 130.2 (C-40), 131.2
(C-30), 133.2 (C-20), 135.0 (C-10),145.8 (C-4). MS (ESI) m/z 240
(M)+. Anal. Calcd for C10H7Cl2N3: C, 50.03; H, 2.94; N, 17.50. Found:
C, 50.55; H, 3.18; N, 17.43.
2. Mycobacterial Growth Assay. The M. tuberculosis H37Rv
ATCC 27294 was grown in 100 mL of Middlebrook 7H9 broth (Difco
Laboratories, Detroit, MI, USA) supplemented with 10% (v/v) OADC
(oleic acid, albumin, dextrose and catalase; Difco). Cultures were
incubated on a rotary shaker at 150 rpm and 37 ꢀC for 24 h. After the
bacteria were washed, they were suspended in 10 mL of 7H9 broth and
adjusted to 0.1 Mc on the Farland scale, and they were diluted 1:25.
Subsequent 2-fold dilutions were performed in 100 μL of 7H9 broth in
microplates according to Franzblau et al. (1998).31
Briefly, 200 μL of sterile deionized water was added to all outer-
perimeter wells of sterile 96-well plates (Falcon, 3072; Becton Dickinson,
Lincoln Park, NJ) to minimize evaporation of the medium in the test
wells during incubation. The final drug concentrations tested were
0.01ꢀ10.0 μg/mL. Plates were covered, sealed with parafilm, and
incubated at 37 ꢀC for 5 days. After this time, 25 μL of a freshly prepared
1:1 mixture of Alamar Blue (Accumed International, Westlake, Ohio)
reagent and 10% Tween 80 was added to the plate and incubated for 24 h.
A blue color in the well was interpreted as no bacterial growth, a pink
color was scored as growth, and purple indicated growth inhibition.
The MIC was defined as the lowest drug concentration that prevented a
change of color from blue to pink.
3. Cell Cultures and Cytotoxicity Test. The human hepatoma
cell line (HepG2) was cultured in 75 cm2 sterile RPMI 1640 medium
supplemented with 10% heat-inactivated fetal calf serum and 40 mg/L
gentamicin in a 5% CO2 atmosphere at 37 ꢀC. For in vitro cytotoxicity
experiments, the cell monolayer was trypsinized, washed with culture
medium, distributed in a flat-bottomed 96-well plate (5 ꢁ 103 cells/
well), and incubated for 18 h at 37 ꢀC for cell adherence. MTT ((3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was employed,
as described in the literature.32
The HepG2 cell line was incubated with 20 μL of sample compounds
at different concentrations (200ꢀ25 μg/mL) for 24 h in an atmosphere
of 5% CO2 at 37 ꢀC. For the MTT assay, which evaluates mitochondrial
viability, 20 μL of MTT solution (5 mg/mL) was added, and the plates
were incubated for an additional 3 h. After incubation, the supernatant
was carefully removed from the wells followed by the addition of 100 μL
DMSO with thorough mixing. The optical density at 570 and 630 nm
(background) was determined on an ELISA reader. The cell viability was
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Journal of Medicinal Chemistry
ARTICLE
expressed as the percentage of control absorbance obtained in untreated
cells after subtracting the absorbance from an appropriate background.
Last, the minimum lethal dose for 50% of the cells (MLD50) was
determined, as previously described in the literature.33
(11) Moghazeh, S. L.; Pan, X.; Arain, T.; Stover, C. K.; Musser, J. M.;
Kreiswirth, B. N. Comparative antimycobacterial activities of rifampin,
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Mycobacterium tuberculosis isolates with known rpoB mutations. Anti-
microb. Agents Chemother. 1996, 40, 2655–2657.
(12) De Logu, A.; Onnis, V.; Saddi, B.; Congiu, C.; Schivo, M. L.;
Cocco, M. T. Activity of a new class of isonicotinoylhydrazones used
alone and in combination with isoniazid, rifampicin, ethambutol, para-
aminosalicylic acid and clofazimine against Mycobacterium tuberculosis.
J. Antimicrob. Chemother. 2002, 49, 275–282.
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Z. Synthesis and some reactions of 2- acetylimidazo[4,5-b]pyridine.
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’ AUTHOR INFORMATION
Corresponding Author
*Phone: +55 21 39772465. Fax: +55 21 25602518. E-mail:
boechat@far.fiocruz.br.
’ ACKNOWLEDGMENT
(14) Shaharyar, M.;Siddiqui, A. A.; Ali, M. A.;Sriram, D.; Yogeeswari,
We are grateful for fellowships granted by the Foundation for
Research of the State of Rio de Janeiro (FAPERJ) and the
Coordination of the Improvement of Higher Education (CAPES)
and the National Council of R&D (CNPq). This study is a part of
the Platform for Bioassays number II-RPT11B of the Program of
Technological Development in Health Products of the Oswaldo
Cruz Foundation (PDTIS-FIOCRUZ).
0
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TB, tuberculosis; BCG, bacille CalmetteꢀGuꢀerin; HIV, human
immunodeficiency virus; MDR-TB, “multiple drug resistant”
M. tuberculosis;INH, isoniazid;MIC, minimum inhibitory concen-
tration;BGM, kidney cells; IBX, 2-iodoxybenzoic acid; DAST,
dimethylaminosulfur trifluoride; NMR, nuclear magnetic reso-
nance; FTIR, infrared spectroscopy; CHN, elemental analysis;
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