Synthesis, antibacterial and antifungal activities of novel 1,2,4-triazolium derivatives

Article abstract of DOI:10.1002/ardp.200800221

A series of novel 1,2,4-triazolium derivatives was synthesized starting from commercially available 1H-1,2,4-triazole, 2,4-dichlorobenzyl chloride, or 2,4-difluorobenzyl bromide. Their antibacterial and antifungal activities were evaluated against Staphyl

Full text of DOI:10.1002/ardp.200800221

386
Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
Full Paper
Synthesis, Antibacterial and Antifungal Activities of Novel
1,2,4-Triazolium Derivatives
Yan Luo1, Yi-Hui Lu1, Lin-Ling Gan2, Cheng-He Zhou1, Jun Wu1, Rong-Xia Geng1, and Yi-Yi Zhang1
1 Laboratory of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest
University, Chongqing, P. R. China
2 School of Pharmaceutical Sciences, Southwest University, Chongqing, P. R. China
A series of novel 1,2,4-triazolium derivatives was synthesized starting from commercially avail-
able 1H-1,2,4-triazole, 2,4-dichlorobenzyl chloride, or 2,4-difluorobenzyl bromide. Their antibac-
terial and antifungal activities were evaluated against Staphylococcus aureus ATCC 29213, Escheri-
chia coli ATCC 25922, Bacillus proteus, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans
ATCC 76615, and Aspergillus fumigatus. All structures of the new compounds were confirmed by
NMR, IR, and MS spectra, and elemental analyses. The antimicrobial tests showed that most of
synthesized triazolium derivatives exhibit significant antibacterial and antifungal activities in
vitro. 1-(2,4-Difluorobenzyl)-4-dodecyl-1H-1,2,4-triazol-4-ium bromide and 1-(2,4-Dichlorobenzyl)-
4-dodecyl-1H-1,2,4- triazol-4-ium bromide were the most potent compounds against all tested
strains with the MIC values ranging from 1.05 to 8.38 lM. They exhibited much stronger activ-
ities than the standard drugs chloramphenicol and fluconazole which are in clinical use. The
results also showed that the antimicrobial activities of triazolium derivatives depend upon the
type of substituent, the length of the alkyl chain, and the number of triazolium rings.
Keywords: Antibacterial activity / Antifungal activity / 1,2,4-Triazolium derivatives /
Received: December 3, 2008; accepted: April 3, 2009
DOI 10.1002/ardp.200800221
numerous researches have been focused on triazole
derivatives as antimicrobial agents by replacement of the
imidazolyl ring with a triazolyl nucleus.
Introduction
Azole compounds including imidazole and triazole
derivatives are important types of antimicrobial drugs in
clinical use. Imidazole derivatives such as miconazole
and econazole were earlier antifungal agents. Along with
the introduction of triazole compounds, for example flu-
conazole and itraconazole, it was found that triazole
compounds exhibited better antimicrobial activities and
lower toxicity [1], and as major antimicrobial agents they
are currently widely used in the clinic. The growing prob-
lem of antimicrobial resistance has induced additional
urgency to design and develop novel types of antimicro-
bial compounds with chemical structures different from
the traditional drugs and improved activities. Up to now,
Recently, a great deal of effort has been made toward
imidazolium salts directly due to their wide range of
potential applications in the fields of chemistry (as
molecular and anion receptors [2], ionic liquids [3, 4], N-
heterocyclic carbenes [5], etc.), medicinal chemistry (as
antimicrobial [6–8], antitumor [9, 10], and plasmid-DNA
cleavage agents [11] etc.), and agricultural aspects (as bio-
cides, herbicides [12], etc.). As new types of antimicrobial
compounds, a series of imidazolium compounds (1a–1k,
Fig. 1) have been reported; they showed significant anti-
bacterial and antifungal activities [7, 8]. It was found that
the type of substituent and the length of the alkyl chain
have an important effect on the antimicrobial activities.
Generally, the mode of action of quaternary ammonium
compounds consists of their interaction with the cyto-
plasmic membrane of bacteria and the subsequent loss of
permeability properties of the membrane [8].
Correspondence: Prof. Dr. Cheng-He Zhou, Laboratory of Bioorganic &
Medicinal Chemistry, School of Chemistry and Chemical Engineering,
Southwest University, Chongqing 400715, P. R. China.
E-mail: zhouch@swu.edu.cn
Fax: + 86 23 682-54967
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
1,2,4-Triazolium Derivatives
387
Figure 2. Structures of triazolium compounds.
ble aromatic and aliphatic substituents could markedly
affect the biological activities of triazole derivatives, espe-
cially some halogen-substituted aromatic compounds
such as 2,4-dichlorobenzyl, 2,4-difluorobenzyl ones, were
found to be biologically important and could improve
the antimicrobial activities [16, 17].
In view of this, a series of novel 1,2,4-triazolium deriv-
atives 5–7 were designed and synthesized starting from
2,4-dichlorobenzyl chloride or 2,4-difluorobenzyl bro-
mide (Scheme 1), and their antibacterial and antifungal
activities were evaluated. Various functional groups
including aralkyl and alkyl types, as well as alkyl chains
of different lengths were introduced into the target com-
pounds in order to investigate their structure-activity
relationships.
Figure 1. Structures of imidazolium compounds.
It is rational to investigate triazolium compounds as
novel antimicrobial agents. So far, however, triazolium
derivatives as antimicrobial agents have been reported
rather seldom. Some reports in literature showed that
the introduction of a positive charge group in the tria-
zole derivatives is helpful to increase the water solubility
and membrane permeability [13, 14], which could result
in the enhancement of biological activities. Very
recently, it was reported in the literature that 2-hydroxy-
phenacyl triazolium derivatives (2a–2f, Fig. 2) exhibited
significant antifungal activities [15]. In addition, many
investigations could show that the introduction of varia-
Results and discussion
Chemistry
The intermediates 4a and 4b were prepared by the reac-
tion of 1H-1,2,4-triazole with 2,4-dichoro benzyl chloride
Scheme 1. Synthetic route of triazo-
lium derivatives 5–7.
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Y. Luo et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
or 2,4-difluoro benzyl bromide in acetonitrile in the pres- albicans ATCC 76615 and A. fumigatus as fungi using the
ence of potassium carbonate. The desired triazolium twofold serial dilution technique. The minimum inhibi-
derivatives 5–7 were synthesized by alkylation of inter- tory concentrations (MIC) were determined and com-
mediates 4a or 4b with a series of alkyl, aralkyl halides or pared to chloramphenicol and fluconazole as standard
dihalides, which were commercially available or were drugs. All these antimicrobial data are given in Table 1.
prepared by conventional methodology via bromination The results showed that most of the target compounds
or chlorination of the corresponding precursors. The are able to inhibit significantly the growth of the
required triazolium compounds 5a–g, 6a–c, 7a–e were screened microorganisms in vitro with MIC values rang-
obtained in yields ranging from 36.6% to 95.3% after ing from 1.13 to 37.78 lM.
purification by washing with petroleum ether (30–608C).
Saturated aqueous ammonium hexafluorophosphate Antibacterial activity
was added dropwise into the aqueous solution of com- The antibacterial tests indicated that most title com-
pound 6a to give triazolium hexafluorophosphate pounds exhibited obvious activities against all tested
[18, 19]. The corresponding triazolium iodide 6d was strains in vitro, and the triazolium compounds 5–7 gave
obtained by adding tetrabutyl ammonium iodide drop- stronger activities than the corresponding precursor tria-
wise into the acetonitrile solution of this triazolium hex- zoles 4a and 4b (Table 1). This suggested the significant
afluorophosphate.
effect of triazolium on antibacterial activities.
The experimental results indicated that the tempera-
The alkyl chain length in the triazolium ring had
ture obviously affected the quaternization reaction. noticeable effect on the antibacterial activities. The anti-
When the temperature was below 808C, the reaction bacterial results showed no obvious activities for mono-
went slowly and the obtained yields were very low. It was triazolium compounds 5a, 5f, and 5g with short C2 –C4
also found that the chain length of the alkyl bromide alkyl chain against S. aureus ATCC 29213, E. coli ATCC
influenced the reactions greatly. For example, the prepa- 25922, B. subtilis, and B. proteus. But good activities were
ration of cetyl-containing triazolium salt 5d took about observed for compounds 5b, 5c, 5d, and 5e containing
two weeks while the butyl derivative 5a only took about long alkyl chains with lengths in the range of C8 –C16.
one week. It was noticed that the presence of the triazo- Among the tested alkyl mono-triazolium compounds,
lium moiety in compounds 5–7 resulted in a better water dodecyl triazolium derivatives 5c and 5e showed the
solubility in comparison with the corresponding precur- most potent antibacterial activity with low MIC values
sors 4a–4b, while mono-triazolium compounds possess between 1.05 and 8.38 lM against all tested strains. It
better solubility than bis-triazolium derivatives in other was noticed that the introduction of a hydroxyethyl
solvents such as chloroform, tetrahydrofuran, and ace- group in the triazolium ring for compounds 5f and 5g
tone.
All these new compounds were characterized by IR,
did not markedly improve the antibacterial activity.
For the tested aryl mono-triazolium series 6a–6e, the
NMR, and MS spectra and elemental analyses. The spec- antibacterial activities were weaker in comparison to
tral analyses were consistent with the assigned struc- long-chain alkyl triazolium compounds 5b–5e. The
tures, and spectral data are listed in the experimental sec- lower MIC values for 6a, 6d, and 6e, compared with the
tion. The mass spectra for the target triazolium com- 2,4-diflurorobenzyl triazolium compounds 6b and 6c,
pounds showed a major fragment of [M+ –X] or [M+ –2X]. suggested that 2,4-dichlorobenzyl substitution in the 4-
In the 1H-NMR spectra, all the methylene protons of the position of the triazolium ring be suitable for antibacte-
PhCH2N1 group in triazolium derivatives 5–7 displayed a rial activity. Compounds 6a and 6e containing a counter-
slight downfield shift in their signals as singlet at 5.56–
ion Cl– or I– seemed to possess better antibacterial effi-
5.95 ppm, compared with the corresponding precursors cacy than 6d with the counterion PF6– . Yet, no large differ-
4a (5.54 ppm) and 4b (5.35 ppm). For the protons in the 3- ence for their antibacterial effect was observed in the
and 5-position of triazolium rings large downfield shifts presence of different counterion anions among aryl tria-
appeared caused by the presence of positive charges in zoliums 6a, 6d, and 6e with the same cation moiety.
the triazolium derivatives.
Therefore, here an effect of the counterion anions on the
antibacterial activities was not obvious, and further
study is necessary in order to deduce the anion–activity
2.2 Biological activities
The prepared compounds 4–7 were evaluated for their relationships.
antimicrobial activities against S. aureus ATCC 29213 and
All bis-triazolium salts 7a–7e linked by aliphatic or
B. subtilis as Gram-positive, E. coli ATCC 25922, P. aerugi- aralkyl aliphatic spacer gave significant antibacterial
nosa, and B. proteus as Gram-negative bacteria as well as C. effect against most of the tested strains, and their activ-
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Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
1,2,4-Triazolium Derivatives
389
Table 1. Antibacterial and antifungal activities of compounds 4–7.
MIC lM (lg/mL)
Compound
C. albicans
A. fumigatus
S. aureus
E. coli
P. aeruginosa
B. proteus
B. subtilis
ATCC 76615
ATCC 29213
ATCC 25922
4a
4b
5a
5b
5c
5d
5e
5f
5g
6a
6b
6c
6d
6e
7a
7b
A2244.6 (A512)
A2623.4 (A512)
A1402.4 (A512)
75.97 (32)
A2244.6 (A512)
A2623.4 (A512)
A1402.4 (A512)
75.97 (32)
2244.6 (512)
2623.4 (512)
350.59 (128)
4.75 (2)
1.05 (0.5)
0.94 (0.5)
1.13 (0.5)
58.04 (16)
51.85 (16)
4.72 (2)
327.67 (128)
636.53 (256)
30.01 (16)
7.77 (4)
95.23 (64)
1.43 (1)
A2244.6 (A512)
2623.4 (512)
A1402.4 (A512)
37.98 (16)
8.38 (4)
A2244.6 (A512)
2623.4 (512)
1402.4 (512)
37.98 (16)
1.05 (0.5)
A2244.6 (A512)
2623.4 (512)
1402.4 (512)
18.99 (8)
A2244.6 (A512)
2623.4 (512)
1402.4 (512)
37.98 (16)
4.19 (2)
8.38 (4)
30.00 (16)
4.50 (2)
4.19 (2)
30.00 (16)
4.50 (2)
1.05 (0.5)
3.75 (2)
1.13 (0.5)
3.75 (2)
4.50 (2)
A959.84 (A512)
30.00 (16)
1.13 (0.5)
1867.2 (512)
1659.2 (512)
9.44 (4)
327.67 (128)
636.53 (256)
15.00 (8)
4.50 (2)
A1867.2 (A512)
A1659.2 (A512)
604.42 (256)
A1310.7 (A512)
A1273.1 (A512)
960.49 (A512)
497.09 (256)
761.83 (512)
22.85 (16)
A1867.2 (A512)
A1659.2 (A512)
604.42 (256)
A1310.7 (A512)
A1273.1 (A512)
480.2 (256)
497.09 (256)
761.83 (512)
22.85 (16)
A1867.2 (A512)
A1659.2 (A512)
37.78 (16)
327.67 (128)
636.53 (256)
60.03 (32)
31.07 (16)
190.46 (128)
11.43 (8)
928.61 (256)
829.58 (256)
37.78 (16)
327.67 (128)
636.53 (256)
60.03 (32)
62.14 (32)
23.81 (16)
0.71 (0.5)
1867.2 (512)
1659.2 (512)
75.55 (32)
163.84 (64)
636.53 (256)
120.06 (64)
31.07 (16)
95.23 (64)
5.71 (4)
7.77 (4)
380.91 (256)
11.43 (8)
7c
7d
7e
677.04 (512)
355.50 (256)
A782.53 (A512)
–
677.04 (512)
A711.00 (A512)
A782.53 (A512)
–
42.32 (32)
2.78 (2)
6.11 (4)
169.26 (128)
44.44 (32)
24.45 (16)
49.52 (16)
–
169.26 (128)
44.44 (32)
48.91 (32)
A1584.5 (A512)
-
84.63 (64)
44.44 (32)
24.45 (16)
49.52 (16)
–
338.52 (256)
22.22 (16)
6.11 (4)
A1584.5 (A512)
–
Chloramphenicol
Fluconazole
A1584.5 (A512)
52.24 (16)
A1671.7 (A512)
-
a)
Minimum inhibitory concentrations were determined by micro broth dilution method using 96-well microtiter plates.
MIC A700 lM against all strains and were considered to be inactive. MIC values in lg/mL are given in brackets.
b)
ities depended on the linked spacer. Among these bis-tria- more potent antifungal activity compared with the refer-
zolium derivatives, compound 7b with a (CH2)6 spacer ence drug fluconazole (MIC = 52.24 lM). Surprisingly, tri-
showed the best antibacterial efficacy. It could effectively azolium compounds 5c and 5e containing dihalobenzyl
inhibit the growth of the tested bacteria at concentra- and dodecyl moieties, respectively, showed quite low
tions ranging from 0.71 to 11.43 lM and gave higher MIC values of 8.38 and 4.50 lM against C. albicans ATCC
potency than the reference drug chloramphenicol 76615, their antifungal activities were much stronger
(MIC=49.52 lM). The bis-triazolium salt 7a containing a than that of fluconazole being in clinical use. This sug-
(CH2)4-linkage showed better antibacterial activity com- gested that it is necessary to further investigate com-
pared to the corresponding butyl mono-triazolium deriv- pounds 5c and 5e as antifungal agents.
ative 5a. The increased activity of compound 7a could be
attributed to the presence of two triazolium cations in
the molecule. This fact suggests that, most likely, the
electronic effect could be responsible for the good activ-
Conclusion
ity against bacteria [ 20].
In conclusion, a series of novel 1,2,4-triazolium com-
In general, the mono-triazolium derivatives 5b, 5c, 5d, pounds containing a dihalobenzyl group were prepared
and 5e along with bis-triazolium compounds 7b, 7d, and successfully through an easy, convenient, and efficient
7e showed more potent antibacterial activity with synthetic method by using 1H-1,2,4-triazole, 2,4-dichloro-
respect to the reference drug chloramphenicol against benzyl chloride or 2,4-difluorobenzyl bromide as starting
all tested bacteria species. Moreover, the structural fac- materials. All these new compounds were confirmed by
tors such as the type of substituent, the length of the NMR, IR, and MS spectra and elemental analyses, and
alkyl chain, and the number of triazolium rings could their antibacterial and antifungal activities were eval-
efficiently affect their antimicrobial activities.
uated against S. aureus ATCC 29213, E. coli ATCC 25922, B.
proteus, B. subtilis, P. aeruginosa, C. albicans ATCC 76615,
and A. fumigatus. The results showed that most of the syn-
Antifungal activity
The antifungal evaluation showed that for most of syn- thesized triazolium derivatives exhibited significant
thesized triazolium derivatives the activities were rela- antibacterial and antifungal activities in vitro. The mono-
tively weak compared to their antibacterial activity. triazolium derivatives 5c and 5e containing dihalobenzyl
While compounds 5d and 7b (MIC = 30.00 or 22.85 lM, and dodecyl groups, respectively, in the triazolium ring
respectively) against C. albicans ATCC 76615 showed a were the most potent compounds against all tested
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Y. Luo et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
strains with the MIC values ranging from 1.13 to 4.50 lM, 1-(2,4-Difluorobenzyl)-1H-1,2,4-triazole 4b
The synthetic method is the same as for 4a starting from 1-(bro-
and exhibited much stronger activities than the refer-
ence drugs chloramphenicol (MIC = 49.52 lM) and fluco-
nazole (MIC = 52.24 lM). The type of substituent, the
length of the alkyl chain, and the number of triazolium
rings had a notable effect on the antimicrobial activities
of the triazolium derivatives. Further research on these
potential new antimicrobial agents are underway in our
group.
momethyl)-2,4-difluorobenzene (12.34 g, 60 mmol) and 1H-1,2,4-
triazole (4.87 g, 71 mmol). The pure product 4b (7.06 g, 60.1%
yield) was obtained as a white solid.
M.p.: 55–568C; IR (KBr) m: 3122 (Ar-H), 2995 (CH2), 1620, 1532,
1508, 1432, 1442 (aromatic frame ), 1276, 1179, 1141, 1096, 974,
854, 677, 634 cm– 1; 1H-NMR (400 MHz, CDCl3) d: 8.14 (s, 1H, tria-
zole 3-H), 7.95 (s, 1H, triazole 5-H), 7.30–7.28 (m, 1H, Ph 6-H),
6.91–6.84 (m, 2H, Ph 3,5-H), 5.35 (s, 2H, CH2) ppm; MS m/z: 195
[M+]. Analysis calculated for C9H7F2N3: C, 55.39; H, 3.62; N, 21.53.
Found: C, 55.29; H, 3.41; N, 21.61.
This work was partially supported by Natural Science Founda-
tion of Chongqing (CSCT: 2007BB5369, 2006BB4341) and
Southwest University (SWUB2006018, XSGX0602).
4-Butyl-1-(2,4-dichlorobenzyl)-1H-1,2,4-triazol-4-ium
bromide 5a
A mixture of intermediate 4a (508 mg, 2.2 mmol) and 1-butyl
bromide (342 mg, 2.5 mmol) in acetonitrile (15 mL) was stirred
at 808C. After the reaction came to the end, the solvent was
evaporated under reduced pressure. The residue was washed
three times with petroleum ether (30–608C) and dried to give
alkyl mono-triazolium 5a (303 mg, 36.6% yield) as a white solid.
M.p.: 186–1878C; IR (KBr) m: 3013 (Ar-H), 2939, 2820 (CH2),
The authors have declared no conflict of interest.
Experimental
Chemistry
1581, 1564, 1475 (aromatic frame), 1388, 1168, 838, 633 cm– 1
;
Melting points are uncorrected and were recorded on X–6 melt-
ing point apparatus. TLC analyses were done using pre-coated
silica gel plates; spots were visualized with an UV lamp at
254 nm. IR spectra were recorded on a Bio-Rad FTS-185 (Bio-Rad,
Cambridge, MA, USA). 1H-NMR and 13C-NMR spectra were
recorded on a Bruker AV 300 or Varian 400 spectrometer (Bruker
Bioscience, Varian, Palo Alto, CA, respectively, both USA) using
TMS as an internal standard. Chemical shifts were given in d
ppm and signals were described as singlet (s), doublet (d), triplet
(t), quartet (q), broad (br), and multiplet (m). All the solvents used
were of analytical grade only. The mass spectra were recorded
on FINNIGAN TRACE GC/MS (Thermo Electron Corporation, Bre-
men, Germany). Elemental analyses were carried out on a ERBA
1106 (Carlo Erba, Milan, Italy).
1H-NMR (300 MHz, D2O) d: 11.72 (s, 1H, triazole 3-H), 8.87 (s, 1H,
triazole 5-H), 7.61 (s, 1H, Ph 3-H), 7.54 (d, J = 8.0 Hz, 1H, Ph 5-H),
7.44 (d, J = 8.2 Hz, 1H, Ph 6-H), 5.69 (s, 2H, PhCH2), 4.29 (t, J =
6.9 Hz, 2H, NCH2CH2), 1.90–1.81 (m, 2H, NCH2CH2), 1.33–1.27
(m, 2H, -CH2CH3), 0.89 (t, J = 7.2 Hz, 3H, CH3) ppm; 13C-NMR
(75 MHz, D2O) d: 142.6 (triazole 3,5-C), 136.3 (Ph 1-C), 135.1 (Ph 2-
C), 133.3 (Ph 4-C), 130.0 (Ph 6-C), 128.1 (Ph 3,5-C), 53.3 (PhCH2),
48.3 (NCH2CH2), 30.9 (NCH2CH2), 18.7 (CH2CH3), 12.6 (CH3) ppm;
MS m/z: 284 [M+ - Br]. Analysis calculated for C13H16BrCl2N3: C,
42.77; H, 4.42; N, 11.51. Found: C, 42.83; H, 4.55; N, 11.47.
1-(2,4-Dichlorobenzyl)-4-octyl-1H-1,2,4-triazol-4-ium
bromide 5b
Compound 5b was prepared according to the procedure
reported for 5a, starting from triazole derivative 4a (510 mg,
2.2 mmol) and 1-octyl bromide (521 mg, 2.7 mmol), the pure
alkyl mono-triazolium 5b (542 mg, 58.5% yield) was obtained as
a white solid.
M.p.: 218–2258C; IR (KBr) m: 3099, 3002 (Ar-H), 2924, 2854
(CH2), 1583, 1475 (aromatic frame), 1153, 848, 623 cm– 1; 1H-NMR
(400 MHz, CDCl3) d: 11.70 (s, 1H, triazole 3-H), 8.66 (s, 1H, triazole
5-H), 7.66 (d, J = 8.4 Hz, 1H, Ph 3-H ), 7.37 (d, J = 1.6 Hz, 1H, Ph 5-H),
7.27–7.24 (m, 1H, Ph 6-H), 5.82 (s, 2H, PhCH2), 4.45 (t, J = 7.20 Hz,
2H, NCH2CH2), 1.91 (br, 4H, NCH2 (CH2)2), 1.28–1.26 (m, 4H,
CH2(CH2)2CH2CH3), 1.23–1.18 (m, 4H, CH2CH2CH3), 0.80 (t, J =
3.6 Hz, 3H, CH3) ppm; MS m/z: 340 [M+ – Br]. Analysis calculated
for C17H24BrCl2N3: C, 48.48; H, 5.74; N, 9.98. Found: C, 48.15; H,
5.52; N, 9.69.
1-(2,4-Dichlorobenzyl)-1H-1,2,4-triazole 4a
A mixture of 1H-1,2,4-triazole (6.98 g, 100 mmol), 2,4-dichloro-1-
(chloromethyl)benzene (19.61 g, 100 mmol), potassium carbo-
nate (14.84 g, 110 mmol), and TBAB (tetrabutyl ammonium bro-
mide, 5 mg) in acetonitrile (30 mL) was stirred at 458C. After the
reaction came to the end (monitored by TLC, eluent: petroleum
ether / acetone, 2 : 1, v / v), the solvent was evaporated and then
water (30 mL) was added. The resulting mixture was extracted
with dichloromethane (3630 mL), and the combined organic
phases were washed three times with saturated solution of
NaHCO3, dried over Na2SO4, and then evaporated under reduced
pressure. The resulting residue was purified by silica gel column
chromatography (petroleum ether / acetone, 2 : 1, v/v) to give the
intermediate 4a (19.4 g, 85.1% yield) as white solid.
M.p.: 71–728C; IR (KBr) m: 3089 (Ar-H), 2998 (CH2), 1590, 1512,
1475, 1443 (aromatic frame), 1267, 1138, 857, 681 cm– 1; 1H-NMR
(300 MHz, CDCl3) d: 8.28 (s, 1H, triazole 3-H), 8.08 (s, 1H, triazole
5-H), 7.55 (d, J = 1.7 Hz, 1H, Ph 3-H), 7.39–7.36 (m, 1H, Ph 5-H),
7.23 (d, J = 8.3 Hz, 1H, Ph 6-H), 5.54 (s, 2H, CH2) ppm; 13C-NMR
(75 MHz, CDCl3) d: 151.8 (triazole 3-C), 143.0 (triazole 5-C), 135.0
(Ph 1-C), 133.7 (Ph 2-C), 130.6 (Ph 4-C), 130.5 (Ph 6-C), 129.2 (Ph 3-
C), 127.3 (Ph 5-C), 49.8 (CH2) ppm; MS m/z: 227 [M+]. Analysis calcu-
lated for C9H7Cl2N3: C, 47.39; H, 3.09; N, 18.42. Found: C, 47.12;
H, 2.96; N, 18.34.
1-(2,4-Dichlorobenzyl)-4-dodecyl-1H-1,2,4-triazol-4-ium
bromide 5c
Compound 5c was prepared according to the method described
for 5a starting from 4a (512 mg, 2.2 mmol) and 1-dodecyl bro-
mide (672 mg, 2.7 mmol), the pure alkyl mono-triazolium 5c
(879 mg, 84.5% yield) was obtained as a white solid.
M.p.: 228–2328C; IR (KBr) m: 3093, 3016 (Ar-H), 2922, 2853
(CH2), 1583, 1474 (aromatic frame), 1173, 837, 620 cm– 1;1H-NMR
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Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
1,2,4-Triazolium Derivatives
391
(400 MHz, CDCl3) d: 11.71 (s, 1H, triazole 3-H), 8.51 (s, 1H, triazole
5-H), 7.67 (d, J = 8.4 Hz, 1H, Ph 3-H), 7.37 (d, J = 2.0 Hz, 1H, Ph 5-H),
7.27–7.25 (m, 1H, Ph 6-H), 5.82 (s, 2H, PhCH2), 4.44 (t, J = 7.2 Hz,
2H, NCH2CH2), 1.92 (t, J = 6.4 Hz, 2H, NCH2CH2), 1.81 (br, 4H,
N(CH2)2(CH2)2, 1.26–1.17 (m, 14H, -(CH2)7CH3), 0.81 (t, J = 3.2 Hz,
3H, CH3) ppm; MS m/z: 396 [M+ – Br]. Analysis calculated for
C21H32BrCl2N3: C, 52.84; H, 6.76; N, 8.80. Found: C, 52.70; H, 6.68;
N, 8.66.
8.3 Hz, 2H, Ph 6-H), 5.73 (s, 2H, PhCH2), 4.46 (t, J = 5.1 Hz, 2H,
NCH2CH2OH), 3.96 (t, J = 5.1 Hz, 2H, NCH2CH2OH) ppm; 13C-NMR
(75 MHz, DMSO-d6) d: 142.7 (triazole 3,5-C), 133.7 (Ph 1-C), 132.5
(Ph 2-C), 130.7 (Ph 4-C), 127.3 (Ph 6-C), 125.6 (Ph 3,5-C), 56.7
(CH2OH), 50.7 (NCH2CH2OH), 47.9 (PhCH2) ppm; MS m/z: 272 [M+ –
Cl]. Analysis calculated for C11H12Cl3N3O: C, 42.81; H, 3.92; N,
13.62. Found: C, 42.75; H, 4.09; N, 13.75.
1-(2,4-Difluorobenzyl)-4-(2-hydroxyethyl)-1H-1,2,4-
triazol-4-ium chloride 5g
Compound 5g was prepared starting from 2,4-difluorobenzyl-
triazole 4b (1.05 g, 5.4 mmol) and 2-chloroethanol (0.66 g,
8 mmol) following the procedure described for 5f, the alkyl
mono-triazolium 5g (1.12 g, 75.6% yield) was obtained as a white
solid.
1-(2,4-Dichlorobenzyl)-4-hexadecyl-1H-1,2,4-triazol-4-
ium bromide 5d
Compound 5d was synthesized according to the preparation of
5a, starting from 4a (512 mg, 2.2 mmol) and 1-hexadecyl bro-
mide (823 mg, 2.7 mmol), the pure alkyl mono-triazolium 5d
(850 mg, 72.5% yield) was obtained as a white solid.
M.p.: 220–2248C; IR (KBr) m: 3093, 3016 (Ar-H), 2921, 2852
(CH2), 1584, 1472 (aromatic frame), 1172, 838, 620 cm– 1;1H-NMR
(400 MHz, CDCl3) d: 11.61 (d, J = 4.4 Hz, 1H, triazole 3-H), 8.82 (d, J
= 4.8 Hz, 1H, triazole 5-H), 7.64–7.61 (m, 1H, Ph 3-H), 7.34 (br, 1H,
Ph 5-H ), 7.24-7.20 (m, 1H, Ph 6-H), 5.80 (d, J = 2.2 Hz, 2H, PhCH2),
4.43 (br, 2H, NCH2CH2), 2.14–1.90 (br, 4H, NCH2CH2CH2), 1.16 (br,
24H, (CH2)12CH3), 0.79 (t, J = 4.8 Hz, 3H, CH3) ppm; MS m/z: 452 [M+
– Br]. Analysis calculated for C25H40BrCl2N3: C, 56.29; H, 7.56; N,
7.88. Found: C, 56.11; H, 7.47; N, 7.74.
M.p.: 154–1558C; IR (KBr) m: 3317 (OH), 3040 (Ar-H), 2970 (CH2),
1579, 1507, 1433 (aromatic frame), 1391, 1143, 1066, 856,
641 cm– 1; 1H-NMR (300 MHz, DMSO-d6) d: 10.43 (s, 1H, triazole 3-
H), 9.26 (s, 1H, triazole 5-H), 7.74–7.66 (m, 1H, Ph 6-H), 7.43–7.36
(m, 1H, Ph 5-H), 7.23–7.18 (t, J = 7.5 Hz, 1H, Ph 3-H), 5.72 (s, 2H,
PhCH2), 5.48 (s, 1H, OH), 4.36 (t, J = 4.2 Hz, 2H, NCH2CH2OH), 3.76
(t, J = 4.5 Hz, 2H, NCH2CH2OH) ppm; MS m/z: 240 [M+ – Cl]. Anal-
ysis calculated for C11H12ClF2N3O: C, 47.92; H, 4.39; N, 15.24.
Found: C, 47.60; H, 4.48; N, 15.02.
1-(2,4-Difluorobenzyl)-4-dodecyl-1H-1,2,4-triazol-4-ium
1,4-Bis(2,4-dichlorobenzyl)-1H-1,2,4-triazol-4-ium
bromide 5e
chloride 6a
Compound 5e was synthesized according to the preparation of
5a, starting from 2,4-difluorobenzyltriazole 4b (724 mg,
3.7 mmol), the 1-dodecyl bromide (900 mg, 3.6 mmol), the pure
alkyl mono-triazolium 5e (909 mg, 68.3% yield) was obtained as
a white solid.
2,4-Dichlorobenzyltriazole 4a (1.60 g, 7 mmol) was dissolved in
acetonitrile and then 2,4-dichloro -1-(chloromethyl)benzene
(1.37 g, 7 mmol) was added. The mixture was refluxed for 5 days
at 808C and then cooled to room temperature. A white solid was
formed. This solid was filtered and washed three times with
CH2Cl2 to afford pure aralkyl mono-triazolium 6a (2.48 g, 83.5%
yield).
M.p.: 122–1258C; IR (KBr) m: 3099, 3006 (Ar-H), 2959, 2922
(CH2), 1579, 1511, 1439 (aromatic frame), 1141, 1094, 850, 766,
634 cm– 1; 1H-NMR (400 MHz, CDCl3) d: 11.66 (s, 1H, triazole 3-H),
9.09 (s, 1H, triazole 5-H), 7.76–7.71 (m, 1H, Ph 6-H), 6.91–6.86
(m, 1H, Ph 5-H), 6.84–6.78 (m, 1H, Ph 3-H), 5.79 (s, 2H, PhCH2),
4.50–4.46 (t, J = 7.6 Hz, 2H, NCH2CH2), 1.96–1.93 (t, J = 7.2 Hz,
2H, NCH2CH2), 1.28–1.18 (br, 18H, -(CH2)9CH3), 0.84-0.81 (t, J =
6.0 Hz, 3H, CH3) ppm; 13C-NMR (100 MHz, CDCl3) d: 165.1 (Ph 2-C),
162.6 (Ph 4-C), 144.0 (triazole 3-C), 143.1 (triazole 5-C), 133.2 (Ph
6-C), 115.4 (Ph 1-C), 112.3 (Ph 5-C), 104.4 (Ph 3-C), 49.3 (NCH2CH2),
49.0 (PhCH2), 31.8, 30.0, 29.5, 29.4, 29.2, 29.1, 28.8, 26.1, 22.5,
13.9 (CH3) ppm; MS m/z: 364 [M+ – Br]. Analysis calculated for
C21H32BrF2N3: C, 56.76; H, 7.26; N, 9.46. Found: C, 56.82; H, 7.18;
N, 9.33.
M.p.: 198–1998C; IR (KBr) m: 3095, 3054 (Ar-H), 2957 (CH2),
1567, 1517, 1450, 1425 (aromatic frame), 1178, 1071, 861, 839,
768, 628 cm-1; H-NMR (300 MHz, CD3OD) d: 9.10 (s, 2H, triazole
1
3,5-H), 7.67 (d, J = 1.88 Hz, 2H, Ph 3-H), 7.53–7.43 (m, 4H, Ph 5, 6-
H), 5.56 (s, 2H, PhCH2N1), 5.01 (s, 2H, PhCH2N4) ppm; 13C-NMR
(75 MHz, CD3OD) d: 138.1 (triazole 3,5-C), 137.7, 136.5 (Ph 1-C),
134.6, 134.2 (Ph 2-C), 131.2, 130.9 (Ph 4-C), 130.3 (Ph 6-C), 130.0
(Ph 3-C), 129.5, 129.2 (Ph 5-C), 54.3 (PhCH2N1), 50.2 (PhCH2N4)
ppm; MS m/z: 387 [M+ – Cl]. Analysis calculated for C16H12Cl5N3:
C, 45.37; H, 2.86; N, 9.92. Found: C, 45.29; H, 2.75; N, 9.82.
4-(2,4-Dichlorobenzyl)-1-(2,4-difluorobenzyl)-1H-1,2,4-
triazol-4-ium chloride 6b
1-(2,4-Dichlorobenzyl)-4-(2-hydroxyethyl)-1H-1,2,4-
triazol-4-ium chloride 5f
Compound 6b was prepared starting from compound 4b (0.89 g,
4.6 mmol) and 2,4-Dichloro-1-(chloromethyl)benzene (1.0 g,
5.1 mmol) following the method described for 5a. After the reac-
tion came to the end, the mixture was filtered and the solid was
washed three times with CH2Cl2 to give the pure product 6b
(1.07 g, 60.0% yield).
A mixture of compound 4a (0.91 g, 4 mmol) and 2-chloroethanol
(10 mL) in acetonitrile (20 mL) was stirred at 808C. After the reac-
tion was completed, the solvent was removed under reduced
pressure to give crude product. Then the resulting solid was
washed three times with acetonitrile and dried to afford alkyl
mono-triazolium compound 5f (0.92 g, 75.3% yield) as a white
solid.
M.p.: 195–1978C; IR (KBr) m: 3304 (OH), 3023 (Ar-H), 2951 (CH2),
1578, 1475, 1439 (aromatic frame), 1391, 1153, 1064, 849, 766,
628 cm– 1; 1H-NMR (300 MHz, DMSO-d6) d: 11.92 (s, 1H, triazole 3-
H), 8.94 (s, 1H, triazole 5-H), 7.55 (m, 2H, Ph 3,5-H), 7.41 (d, J =
M.p.: 175–1778C; IR (KBr) m: 3082 (Ar-H), 2998, 2938 (CH2),
1615, 1590, 1561, 1504 (aromatic frame), 1141, 1097, 856,
621 cm– 1; 1H-NMR (400 MHz, CDCl3) d: 11.89 (s, 1H, triazole 3-H),
8.71 (s, 1H, triazole 5-H), 8.05 (d, J = 8.4 Hz, 2,4-Cl2Ph 6-H), 7.72–
7.66 (m, 1H, 2,4-F2Ph 6-H), 7.40 (d, J = 2.0 Hz, 2,4-Cl2Ph 5-H), 7.32–
7.30 (m, 1H, 2,4-F2Ph 5-H), 7.00-6.85 (m, 1H, 2,4-Cl2Ph 3-H), 6.83–
6.78 (m, 1H, 2,4-F2Ph 3-H), 5.95 (s, 2H, 2,4-F2PhCH2), 5.79 (s, 2H,
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Y. Luo et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
2,4-Cl2PhCH2); 13C-NMR (100 MHz, CDCl3) d: 165.2–165.1 (2,4-
F2Ph, 2,4-Cl2Ph 2-C), 162.7–162.5 (2,4-F2Ph, 2,4-Cl2Ph 4-C), 160.1–
160.0 (triazole 3-C), 144.1–143.5 (triazole 5-C), 137.2 (2,4-Cl2Ph 6-
C), 135.0 (2,4-Cl2Ph 1-C), 134.0 (2,4-Cl2Ph 5-C), 133.2–133.0 (2,4-
F2Ph 6-C), 128.7–128.6 (2,4-Cl2Ph 3-C), 115.4-115.2 (2,4-F2Ph 1-C),
112.5–122.2 (2,4-F2Ph 5-C), 104.7–104.2 (2,4-F2Ph 3-C), 49.6
(PhCH2N1), 49.0 (PhCH2 N4) ppm; MS m/z: 354 [M+ –Cl]. Analysis
calculated for C16H12Cl3F2N3: C, 49.19; H, 3.10; N, 10.76. Found: C,
48.95; H, 2.89; N, 10.57.
Cl2Ph 3-H), 7.46 (d, J = 8.4 Hz, 1H, 29,49-Cl2Ph 3-H), 7.47 (d, J =
2.0 Hz, 1H, 2,4-Cl2Ph 5-H), 7.42 (d, J = 2.0 Hz, 1H, 29,49-Cl 2Ph 5-H),
7.35–7.32 (m, 1H, 2,4-Cl2Ph 6-H ), 7.31–7.29 (m, 1H, 29,49-Cl2Ph 6-
H ), 5.63 (s, 2H, PhCH2N1), 5.59 (s, 2H, PhCH2N4) ppm; MS m/z: 387
[M+ – I]. Analysis calculated for C16H12Cl4IN3: C, 37.31; H, 2.35; N;
8.16. Found: C, 37.02; H, 1.98; N, 8.03.
4,4'-(Butane-1,4-diyl)bis(1-(2,4-dichlorobenzyl)-1H-1,2,4-
triazol-4-ium) bromide 7a
Compound 7a was synthesized starting from 4a (510 mg,
2.2 mmol) and 1,4-dibromobutane (823 mg, 2.7 mmol), follow-
ing the procedure described for 5a to give alkyl bis-triazoliums
7a (850 mg, 78.2% yield) as a white solid.
M.p.: 264–2658C; IR (KBr) m: 3095 (Ar-H), 2999, 2946 (CH2),
1589, 1574, 1477 (aromatic frame), 1172, 847, 620 cm– 1; 1H-NMR
(300 MHz, DMSO-d6) d: 10.44 (s, 2H, triazole 3-H), 9.33 (s, 2H, tri-
azole 5-H), 7.75 (d, J = 2.0 Hz, 2H, Ph 3-H), 7.66 (d, J = 11.2 Hz, 2H,
Ph 5-H), 7.57–7.54 (m, 2H, Ph 6-H), 5.76 (s, 4H, PhCH2), 4.37 (br,
4H, NCH2CH2), 1.92 (br, 4H, NCH2CH2) ppm; MS m/z: 590 [M+ – Br],
511 [M+ - 2Br]. Analysis calculated for C22H22Br2Cl4N6: C, 39.32; H,
3.30; N, 12.50. Found: C, 39.25; H, 3.22; N, 12.38.
4-(2,4-Difluorobenzyl)-1-(2,4-difluorobenzyl)-1H-1,2,4-
triazol-4-ium bromide 6c
Compound 6c was synthesized according to the procedure
reported for 5a, starting from 2,4-difluorobenzyltriazole 4b
(793 mg, 4.1 mmol) and 1-(bromomethyl)-2,4-difluorobenzene
(1.45 g, 7.0 mmol). The pure aralkyl mono-triazolium 6c (1.35 g,
83.3% yield) was obtained as a white solid.
M.p.: 197–1988C; IR (KBr) m: 3114, 3020 (Ar-H), 2969, 2938
(CH2), 1618, 1568, 1507, 1434 (aromatic frame), 1144, 1096, 978,
630 cm– 1; 1H-NMR (400 MHz, CD3CN) d: 10.06 (s, 1H, triazole 3-H),
8.82 (s, 1H, triazole 5-H), 7.72–7.66 (m, 1H, 2,4-F2Ph 6-H), 7.61–
7.57 (m, 1H, 29,49-F2Ph 6-H), 7.07-6.99 (m, 4H, 2,4-F2Ph 3,5-H, 29,49-
F2Ph 3,5-H), 5.58 (s, 2H, CH2), 5.54 (s, 2H, CH2) ppm; 13C-NMR
(100 MHz, CD3CN) d: 167.2–166.1 (2,4-F2Ph 2-C), 163.9–163.5
(2,4-F2Ph 4-C), 161.7–161.5 (triazole 3-C), 145.5 (triazole 5-C),
134.5–134.3 (2,4-F2Ph 6-C), 118.7 (2,4-F2Ph 1-C), 113.4–113.0 (2,4-
F2Ph 5-C), 105.7–104.9 (2,4-F2Ph 3-C), 50.3 (PhCH2N1), 46.3
(PhCH2N4) ppm; MS m/z: 322 [M+ – Br]. Analysis calculated for
C16H12BrF4N3: C, 47.78; H, 3.01; N, 10.45. Found: C, 47.69; H, 2.83;
N, 10.51.
4,4'-(Hexane-1,6-diyl)bis(1-(2,4-dichlorobenzyl)-1H-
1,2,4-triazol-4-ium) bromide 7b
Compound 7b was prepared the same way as 5a starting from
compound 4a (818 mg, 3.6 mmol) and 1,6-dibromohexane
(976 mg, 4.0 mmol), the pure alkyl bis-triazoliums 7b (1.83 g,
82.3% yield) was obtained as a white solid.
M.p.: 194–2008C; IR (KBr) m: 3095 (Ar-H), 2929, 2853 (CH2),
1576, 1474, 1432 (aromatic frame), 1162, 857, 780, 627 cm– 1;1H-
NMR (400 MHz, DMSO-d6) d: 10.39 (s, 2H, triazole 3-H), 9.30 (s, 2H,
triazole 5-H), 7.74 (d, J = 2.0 Hz, 2H, Ph 3-H), 7.63 (d, J = 8.4 Hz, 2H,
Ph 5-H), 7.55–7.53 (m, 2H, Ph 6-H), 5.73 (s, 4H, PhCH2), 4.26 (t, J =
7.6 Hz, 4H, NCH2CH2), 1.83 (t, 4H, J = 7.2 Hz, NCH2CH2 ), 1.25 (br,
4H, NCH2CH2CH2) ppm; MS m/z: 542 [M+ – 2Br]. Analysis calcu-
lated for C24H26Br2Cl4N6: C, 41.17; H, 3.74; N, 12.00. Found: C,
40.88; H, 3.49; N, 12.26.
4-(2,4-Dichlorobenzyl)-1-(2,4- dichlorobenzyl)-1H-1,2,4-
triazol-4-ium hexafluorophosphate 6d
Compound 6a (1.06 g, 2.5 mmol) was dissolved in water (20 mL)
and then aqueous NH4PF6 (0.44 g, 2.7 mmol; in 5 mL water) was
added dropwise. The mixture was stirred at room temperature
for 0.5 hour. A white solid was formed. The solid was filtered,
washed three times with water and dried to give the pure prod-
uct 6d (1.14 g, 90.6% yield).
4,4'-(Decane-1,10-diyl)bis(1-(2,4-dichlorobenzyl)-1H-
M.p.: 191–1938C; IR (KBr) m: 314, 3085 (Ar-H), 2976 (CH2), 1592,
1567, 1476, 1451 (aromatic frame), 1146, 1072, 867, 823, 623,
556 cm– 1; 1H-NMR (300 MHz, DMSO-d6) d: 10.35 (s, 1H, triazole 3-
H), 9.30 (s, 1H, triazole 5-H), 7.78 (d, J = 9.9 Hz, 2H, 2,4-Cl2Ph 3-H,
29,49-Cl 2Ph 3-H), 7.60–7.55 (m, 4H, 2,4-Cl2Ph 5,6-H, 29,4'-Cl 2Ph 5,6-
H), 5.73 (s, 2H, PhCH2N1), 5.62 (s, 2H, PhCH2N4) ppm; MS m/z: 387
[M+ – PF6 – ]. Analysis calculated for C16H12Cl4F6N3P: C, 36.05; H,
2.27; N, 7.88. Found: C, 36.32; H, 2.30; N, 7.71.
1,2,4-triazol-4-ium) bromide 7c
Compound 7c was prepared according to the synthesis of 5a
starting from compound 4a (572 mg, 2.5 mmol) and 1,10-dibro-
modecane (840 mg, 4.0 mmol); the pure alkyl bis-triazoliums 7c
(1.40 g, 74.2% yield) was obtained as a white solid.
M.p.: 205–2118C; IR (KBr) m: 3093, 3009 (Ar-H), 2951, 2860
(CH2), 1582, 1563, 1476 (aromatic frame), 1387, 1168, 836,
626 cm– 1; 1H-NMR (400 MHz, DMSO-d6) d: 10.42 (s, 2H, triazole 3-
H), 9.30 (s, 2H, triazole 5-H), 7.74 (d, J = 2.4 Hz, 2H, Ph 3-H), 7.65–
7.62 (m, 2H, Ph 5-H), 7.55–7.53 (m, 2H, Ph 6-H), 5.74 (s, 2H,
PhCH2), 5.72 (s, 2H, PhCH2), 4.30–4.25 (m, 4H, NCH2CH2), 3.52 (t, J
= 6.8 Hz, 2H, CH2), 1.86–1.75 (m, 6H, CH2), 1.42–1.37 (m, 4H,
CH2), 1.32-1.26 (m, 4H, CH2) ppm; MS m/z: 675 [M+ – Br], 595 [M+ -
2Br]. Analysis calculated for C28H34Br2Cl4N6: C, 44.47; H, 4.53; N,
11.11. Found: C, 44.56; H, 4.31; N, 10.84.
4-(2,4-Dichlorobenzyl)-1-(2,4- dichlorobenzyl)-1H-1,2,4-
triazol-4-ium iodide 6e
Compound 6d (0.12 g, 0.2 mmol) was dissolved in acetonitrile
(10 mL), and then Bu4N+I– (0.075 g, 0.2 mmol) in acetonitrile
(2 mL) was added dropwise. The mixture was stirred at room
temperature for 0.5 hour. A white solid formed. This solid was
filtered and washed three times with acetonitrile to give pure
aralkyl mono-triazolium iodide 6e (0.10 g, 87.3% yield).
M.p.: 185–1868C; IR (KBr) m: 3126, 3060 (Ar-H), 2976 (CH2),
1589, 1566, 1474, 1438 (aromatic frame), 1142, 1072, 863, 842,
777, 611 cm– 1; 1H-NMR (300 MHz, DMSO-d6) d: 10.48 (s, 1H, tria-
zole 3-H), 9.11 (s, 1H, triazole 5-H), 7.61 (d, J = 8.0 Hz, 1H, 2,4-
4,4'-(1,4-Phenylenebis(methylene) bis(1-(2,4-
dichlorobenzyl) -1H-1,2,4-triazol-4-ium) bromide 7d
2,4-Dichlorobenzyltriazole 4a (1.15 g, 5 mmol) was dissolved in
acetonitrile and then 1,4-bis (bromomethyl)benzene (0.66 g,
2.5 mmol) was added. The mixture was refluxed for 5 days and
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Arch. Pharm. Chem. Life Sci. 2009, 342, 386–393
1,2,4-Triazolium Derivatives
393
was allowed to cool. A white solid was formed. This solid was fil-
tered and washed three times with CH2Cl2 to afford pure aralkyl
bis-triazoliums 7d (1.72 g, 95.3% yield).
ronbc Laboraton Technology CO., Ltd, Beijing, China) were made
resulting in eleven wanted concentrations (0.5 to 512 lg/mL) of
each tested compound. These dilutions were inoculated and
incubated at 358C for 24 hours. The drug MIC80 was defined as
the first well with an approximate 80% reduction in growth
compared to the growth of the drug-free well. The minimum
inhibitory concentration (MIC80) values (in lM and lg/mL) were
summarized in Table 1.
M.p.: A2708C; IR (KBr) m: 3010 (Ar-H), 2950 (CH2), 1578, 1562
(aromatic frame), 1168, 836, 626 cm– 1 1H-NMR (300 MHz,
;
DMSO-d6) d: 10.46 (s, 2H, triazole 3-H), 9. 36 (s, 2H, triazole 5-H),
7.77 (br, 2H, 2,4-Cl2Ph 3-H, 29,49-Cl2Ph 3-H), 7.66-7.61 (m, 2H, 2,4-
Cl2Ph 5-H, 29,49-Cl2Ph 5-H), 7.57 (br, 4H, Ph 2,3,5,6-H), 7.52–7.45
(m, 2H, 2,4-Cl2Ph 6-H, 29,49-Cl2Ph 6-H), 5.73 (d, J = 6.0 Hz, 4H, 2,4-
Cl2PhCH2N1), 5.55 (d, J = 11.4 Hz, 4H, PhCH2N4) ppm; MS m/z: 638
[M+ - Br], 559 [M+ – 2Br]. Analysis calculated for C26H22Br2Cl4N6: C,
43.37; H, 3.08; N, 11.67. Found: C, 43.24; H, 2.96; N, 11.49.
References
[1] B. E. De Pauw, Int. J. Antimicrob. Agents 2000, 16, 147–150.
4,4'-(1,4-Phenylenebis(methylene)) bis(1-(2,4-
[2] J. Yoon, S. K. Kim, N. J. Singh, K. S. Kim, Chem. Soc. Rev.
2006, 35, 355–360.
difluorobenzyl) -1H-1,2,4-triazol-4-ium) bromide 7e
Compound 7e was synthesized starting from 2,4-difluorobenzyl-
triazole 4b (700 mg, 2 mmol) and 1,4-bis (bromomethyl)benzene
(203 mg, 1 mmol) following the procedure reported for 5a. The
pure aralkyl bis-triazoliums 7e (528 mg, 85.9% yield) was
obtained as a white solid.
[3] S. J. Zhang, X. M. Lu in Ionic Liquids: From Fundamentals to
Applications, Science Press, Beijing, 2006, pp.149–193.
[4] T. L. Greaves, C. J. Drummond, Chem. Rev. 2008, 108, 206–
237.
M.p.: A2708C; IR (KBr) m: 3091, 3027 (Ar-H), 2972 (CH2), 1608,
1574, 1509, 1469 (aromatic frame), 1144, 831, 761, 622 cm– 1; 1H-
NMR (300 MHz, DMSO-d6) d: 10.48 (s, 2H, triazole 3-H), 9.37 (s, 2H,
triazole 5-H), 7.73–7.65 (m, 2H, 2,4-F2Ph 6-H, 29,49-F2Ph 6-H), 7.60
(s, 4H, Ph 2,3,5,6-H), 7.43–7.36 (m, 2H, 2,4-F2Ph 5-H, 29,49-F2Ph 5-H
), 7.24-7.19 (m, 2H, 2,4-F2Ph 3-H, 29,49-F2Ph, 3-H), 5.70 (s, 4H, 2,4-F2
PhCH2N1), 5.58 (s, 4H, PhCH2N4) ppm; MS m/z: 575 [M+ - Br], 496
[M+ – 2Br]. Analysis calculated for C26H22Br2F4N6: C, 47.73; H,
3.39; N, 12.84. Found: C, 47.83; H, 3.20; N, 12.66.
[5] A. M. Voutchkova, L. N. Appelhans, A. R. Chianese, R. H.
Crabtree, J. Am. Chem. Soc. 2005, 127, 17624–17625.
[6] P. Rajakumar, K. Sekar, V. Shanmugaiah, N. Mathivanan,
Bioorg. Med. Chem. Lett. 2008, 18, 4416–4419.
[7] K. D. Demberelnyamba, K. S. Kim, S. Choi, S. Y. Park, et al.,
Bioorg. Med. Chem. 2004, 12, 853–857.
[8] M. Hindi, T. J. Siciliano, S. Durmus, M. J. Panzner, et al., J.
Med. Chem. 2008, 51, 1577–1583.
[9] X. D. Yang, X. H. Zeng, Y. L. Zhang, C. Qing, et al., Bioorg.
Med. Chem. Lett. 2009, 19, 1892–1895.
Antibacterial and antifungal assays
The in-vitro minimal inhibitory concentrations (MICs) of the title
compounds were determined by the modified microbroth dilu-
tion method according to the methods defined by the National
Committee for Clinical Laboratory Standards [21]. The test
strains were provided by the School of Pharmaceutical Sciences,
Southwest University. Fluconazole and Chloramphenicol
obtained from their respective manufacturers served as con-
trols.
[10] C. G. Fortuna, V. Barresi, G. Berellini, G. Musumarra, Bio-
org. Med. Chem. 2008, 16, 4150–4159.
[11] Q. L. Li, J. Huang, Q. Wang, N. Jiang, C. Q. Xia, H. H. Lin, J.
Wu, X. Q. Yu, Bioorg. Med. Chem. 2006, 14, 4151–4157.
[12] I. Bꢀlai, G. Fekete, Pest. Manag. Sci. 2003, 59, 401–409.
[13] Y. Ueda, J. D. Matiskella, J. Golik, T. P. Connolly, et al., Bio-
org. Med. Chem. Lett. 2003, 13, 3669–3672.
The prepared compounds 4–7 were evaluated for their anti-
bacterial activity against S. aureus ATCC 29213 and B. subtilis as
Gram-positive, E. coli ATCC 25922, P. aeruginosa, and B. proteus as
Gram-negative bacteria. The bacterial suspension was adjusted
with sterile saline to a concentration of 16105 CFU. The test
compounds were dissolved in dimethyl sulfoxide (DMSO) to pre-
pare the stock solutions. The test compounds and reference
drugs were prepared in Mueller–Hinton broth (Guangdong
huaikai microbial sci.& tech co., Ltd, Guangzhou, Guangdong,
China) by twofold serial dilution to obtain the required concen-
trations of 512, 256, 128, 64, 32, 16, 8, 4, 2, 1, 0.5 lg/mL. These
dilutions were inoculated and incubated at 378C for 24 h. To
ensure that the solvent had no effect on bacterial growth, a con-
trol test was performed with test medium supplemented with
DMSO at the same dilutions as used in the experiment.
The new compounds were evaluated for their antifungal activ-
ity against C. albicans ATCC 76615 and A. fumigatus. A spore sus-
pension in sterile distilled water was prepared from 1-day old
culture of the fungi growing on Sabouraud agar (SA) media. The
final spore concentration was 1–56103 spore mL– 1. From the
stock solutions of the tested compounds and reference antifun-
gal fluconazole, dilutions in sterile RPMI 1640 medium (Neu-
[14] J. Ohwada, M. Tsukazaki, T. Hayase, N. Oikawa, et al., Bio-
org. Med. Chem. Lett. 2003, 13, 191–196.
[15] S. Emami, A. Foroumadi, M. Falahati, E. Lotfali, et al., Bio-
org. Med. Chem. Lett. 2008, 18, 141–146.
[16] P. Karegoudar, D. J. Prasad, M. Ashok, M. Mahalinga, et al.,
Eur. J. Med. Chem. 2008, 43, 808–815.
[17] M. S. Karthikeyan, B. S. Holla, N. S. Kumari, Eur. J. Med.
Chem. 2008, 43, 309–314.
[18] Y. R. Mirzaei, B. Twamley, J. M. Shreeve, J. Org. Chem. 2002,
67, 9340–9345.
[19] Z. Zeng, B. S. Phillips, J. C. Xiao, J. M. Shreeve, Chem. Mater.
2008, 20, 2719–2726.
[20] K. Malek, G. Schroeder, L. M. Proniewicz, Vib. Spectroscopy
2007, 44, 19–29.
[21] National Committee for Clinical Laboratory Standards
2002. Reference Method for Broth Dilution Antifungal Sus-
ceptibility Testing of Yeasts Approved standard. Document
M27–A2, National Committee for Clinical Laboratory
Standards, Wayne, PA, USA.
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