Efficient synthesis, antitubercular and antimicrobial evaluation of 1,4-disubstituted 1,2,3-triazoles with amide functionality

Article abstract of DOI:10.1007/s00706-019-2361-9

Abstract: A series of 21 amide linked 1,4-disubstituted-1,2,3-triazoles were achieved via one-pot synthesis through Cu(I) catalyzed click reaction between terminal alkynes and 2-azido-N-substituted acetamides. Newly formed triazoles were characterized by various spectroscopic techniques (FT-IR, ¹H NMR, ¹³C NMR spectroscopy, and HRMS) and investigated for in vitro antitubercular evaluation against bacteria, i.e., Mycobacterium tuberculosis and antimicrobial evaluation against Bacillus subtilis, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. Some of the synthesized triazole derivatives were found to exhibit moderate inhibitory activity against the tested antitubercular strain, whereas one compound displayed a significant inhibitory activity against most of the tested microbial strains. Graphical abstract: [Figure not available: see fulltext.].

Full text of DOI:10.1007/s00706-019-2361-9

Monatshefte für Chemie - Chemical Monthly
https://doi.org/10.1007/s00706-019-2361-9
ORIGINAL PAPER
Efcient synthesis, antitubercular and antimicrobial evaluation
of 1,4‑disubstituted 1,2,3‑triazoles with amide functionality
C. P. Kaushik1 · Ashima Pahwa1 · Dharmendra Singh2 · Krishan Kumar1 · Raj Luxmi1
Received: 9 October 2018 / Accepted: 8 January 2019
© Springer-Verlag GmbH Austria, part of Springer Nature 2019
Abstract
A series of 21 amide linked 1,4-disubstituted-1,2,3-triazoles were achieved via one-pot synthesis through Cu(I) catalyzed
click reaction between terminal alkynes and 2-azido-N-substituted acetamides. Newly formed triazoles were characterized
by various spectroscopic techniques (FT-IR, 1H NMR, 13C NMR spectroscopy, and HRMS) and investigated for in vitro
antitubercular evaluation against bacteria, i.e., Mycobacterium tuberculosis and antimicrobial evaluation against Bacillus
subtilis, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger.
Some of the synthesized triazole derivatives were found to exhibit moderate inhibitory activity against the tested antituber-
cular strain, whereas one compound displayed a signifcant inhibitory activity against most of the tested microbial strains.
Graphical abstract
Keywords Click reaction · Heterocycles · 1,4-Disubstituted · 1,2,3-Triazoles · Alkynes · One-pot synthesis · Biological
activity
Introduction
efective chemotherapy, still, tuberculosis has become lead-
ing cause of mortality. Infectious diseases caused by micro-
organisms have also been increasing threat to public health.
Use of conventional antibiotics has now become inefective
due to increasing resistance in strains against them. Emer-
gence of multi-drug resistant strains against tuberculosis and
microbial infections has become an alarming issue that drew
attention of medicinal researchers to develop new drug pro-
fle for their efective treatment. In this perspective, triazoles
have proved to be potent antitubercular and antimicrobial
agents due to extensive therapeutic importance [1, 2].
Triazoles, a signifcant class of nitrogen containing het-
erocycles, are attractive structural motifs which displayed
versatility in diverse felds such as material sciences, syn-
thetic organic chemistry, and drug discovery [3–5]. Triazole
derivatives have been widely utilized in industries as dye-
stufs, agrochemicals, optical brighteners, photostabilizers,
Tuberculosis is one of the highly contagious and major chal-
lenging diseases around the world. Mycobacterium tubercu-
losis, etiologic agent of tuberculosis, led to the death of large
number of people for more than fve millennia. Despite avail-
ability of useful vaccine bacille Calmette–Guerin (BCG) and
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s00706-019-2361-9) contains
supplementary material, which is available to authorized users.
* C. P. Kaushik
kaushikcp@gmail.com
1
Department of Chemistry, Guru Jambheshwar University
of Science and Technology, Hisar, Haryana, India
2
Centre for Research and Development, IPCA Lab Ltd.,
Kandivali, Mumbai, Maharashtra, India
Vol.:(0123456789)
1 3

C. P. Kaushik et al.
corrosion inhibitors [6, 7], etc. In spite of these industrial
applications, 1,2,3-triazole scafolds emerged as imperative
pharmacophore owing to their prevalent biological proper-
ties like antiviral [8], antimicrobial [9, 10], antiHIV [11],
antiproliferative [12], antimalarial [13, 14], anticancer [15],
antiallergic [16], anticonvulsant [17], antioxidant [18],
antitubercular [19], etc.
of copper sulfate pentahydrate and sodium ascorbate in N,N-
dimethylformamide to lead desired products 4a–4u in good
yield.
Structures of newly synthesized triazole derivatives
4a–4u were explicated by diferent spectral techniques,
i.e., FT-IR, 1H NMR, 13C NMR spectroscopy, and HRMS.
FT-IR spectra of synthesized compounds confrmed the for-
mation of triazoles due to appearance of absorption bands
in the region of 3211–3308 cm−1 (N–H, str., amide), 3123-
3185 cm−1 (C–H, str., triazole ring), and 1666–1703 cm−1
(>C=O str. amide). In 1H NMR spectra, singlet resonated in
the region at δ=8.54–8.76 and 10.39–11.18 ppm due to tria-
In past, plethora of methods have been developed for
synthesis of 1,2,3-triazoles for different purposes [20].
Most established strategy for the synthesis of disubstituted
1,2,3-triazoles from azides and terminal alkynes was intro-
duced by Huisgen [21]. This conventional approach afords
formation of both 1,4- and 1,5-disubstituted triazoles at ele-
vated temperature. To conquer the problem of poor regiose-
lectivity, Sharpless [22] and Meldal [23] in 2002 invented
Cu(I) catalyzed click reaction of terminal alkynes and azides
to generate 1,4-disubstituted 1,2,3-triazoles only. How-
ever, this experimentally simple and highly regioselective
approach appears to possess enormous scope in many other
areas like bioconjugation [24], polymer chemistry [25], pep-
tidomimetics [26], and supramolecular chemistry [27].
Prompted by the above considerations and as an exten-
sion of our previous work on synthesis of biologically
active 1,4-disubstituted 1,2,3-triazoles [28–31], we, herein,
reported the synthesis, and antitubercular and antimicrobial
potential of amide linked 1,4-disubstituted 1,2,3-triazoles
via Cu(I) catalyzed click reaction between terminal alkynes
and 2-azido-N-substituted acetamides. All the synthesized
triazoles were well characterized by the spectroscopic
zolyl proton and N–H proton, respectively. Moreover, in 13
C
NMR spectra, signals displayed in region at δ=145.6–146.8,
123.0–124.3, and 164.0–165.8 ppm designated to C4, C5 of
triazole ring and carbonyl carbon of amide linkage. Fur-
thermore, the results obtained from high-resolution mass
spectral analysis were found in accordance to their calcu-
lated values.
Antitubercular activity
All synthesized triazole derivatives 4a–4u were screened
for in vitro antitubercular activity against bacterial strain
M. tuberculosis H37RV (MTCC 200) by Lowenstein–Jensen
(L. J.) slope method. Isoniazid was used as a standard
drug. Results were recorded in terms of minimum inhibi-
tory concentration (µmol/cm3). As refected from Table 1,
some of synthesized triazole derivatives were found to
display noteworthy antitubercular activity against strain
used for experimentation. Compound 4a possessed good
antitubercular potential in comparison to the standard
drug. It has been deduced that compound 4c (0.1933 µmol/
cm3), 4l (0.1530 µmol/cm3), 4q (0.1831 µmol/cm3), and 4t
(0.1333 µmol/cm3) also showed moderate inhibitory activity
against tested bacterial strain.
1
techniques FT-IR, H NMR, 13C NMR spectroscopy, and
HRMS, and also assessed for in vitro antitubercular potential
against Mycobacterium tuberculosis; antimicrobial poten-
tial against Bacillus subtilis, Staphylococcus epidermidis,
Escherichia coli, Pseudomonas aeruginosa, Candida albi-
cans, and Aspergillus niger.
Results of antitubercular screening inferred that com-
pounds possessing nitro group on anilide ring found to dis-
play a better inhibitory activity in comparison to compounds
substituted with methoxy group on anilide ring. Among
synthesized compounds substituted with halogen moiety,
compound having both fuoro and bromo groups was found
to behave as good antitubercular agent.
Results and discussion
Chemistry
Synthetic strategy for preparation of N-aryl-2-(4-substi-
tuted-1H-1,2,3-triazol-1-yl)acetamides 4a–4u is given
in Scheme 1. 2-Bromo-N-substituted acetamides 2a–2g
[32] were synthesized by reacting aromatic amines 1a–1g
with bromoacetyl bromide in the presence of base potas-
sium carbonate in dichloromethane. Afterwards, target
1,4-disubstituted 1,2,3-triazoles 4a–4u with amide func-
tionality were obtained by one-pot synthesis through click
reaction between commercially available terminal alkynes
3a–3c and 2-azido-N-substituted acetamides (which were
attained in situ by reaction of 2-bromo-N-substituted aceta-
mides 2a–2g and sodium azide) by utilizing catalytic amount
Antimicrobial activity
All newly synthesized triazole derivatives 4a–4u were
assessed for in vitro antimicrobial evaluation against B.
subtilis (MTCC 441), S. epidermidis (MTCC 6880) (Gram-
positive bacteria), E. coli (MTCC 1652), P. aeruginosa
(MTCC 424) (Gram-negative bacteria), and C. albicans
(MTCC 183), and A. niger (MTCC 8189) (fungi) by serial
dilution technique [33]. Ciprofoxacin and fuconazole were
1 3

Efcient synthesis, antitubercular and antimicrobial evaluation of 1,4‑disubstituted…
Scheme 1
Compound
4a
Ar
C6H5
R
H
H
H
H
H
H
H
4-CH3
4-CH3
4-CH3
4-CH3
4-CH3
4-CH3
4-CH3
3-F
3-F
3-F
3-F
3-F
3-F
3-F
Yield /%
82
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
4-CH3OC6H4
4-NO2C6H4
4-FC6H4
4-ClC6H4
4-BrC6H4
α-Naphthyl
C6H5
4-CH3OC6H4
4-NO2C6H4
4-FC6H4
4-ClC6H4
4-BrC6H4
α-Naphthyl
C6H5
4-CH3OC6H4
4-NO2C6H4
4-FC6H4
4-ClC6H4
4-BrC6H4
α-Naphthyl
88
81
85
86
78
88
83
81
87
80
86
85
78
80
77
88
79
75
85
87
4s
4t
4u
used as standard drugs against bacteria and fungi, respec-
tively. Results were recorded in terms of MIC (minimum
inhibitory concentration) which was expressed in µmol/cm3.
It can be revealed from antibacterial screening data
(Table 2) that most of the synthesized triazoles exhib-
ited moderate-to-good antibacterial activity against tested
bacterial strains. Among all the synthesized triazole
derivatives, compound 4r found to exhibit a signifcant
antibacterial activity against all the bacterial strains. Com-
pound 4g (MIC 0.0190 µmol/cm3), 4k (MIC 0.0201 µmol/
cm3), and 4r (MIC 0.0199 µmol/cm3) against B. subtilis;
4c (MIC 0.0193 µmol/cm3), 4q (MIC 0.0183 µmol/cm3),
1 3

C. P. Kaushik et al.
Table 1 In vitro antitubercular activity of 1,4-disubstituted 1,2,3-tria-
zoles 4a–4u
Table 2 In vitro antibacterial activity of 1,4-disubstituted 1,2,3-tria-
zoles 4a–4u
Compound
Minimum inhibitory
concentration (MIC/
Compound
Minimum inhibitory concentration (MIC/µmol cm−3
Gram-positive bacteria Gram-negative bacteria
B. subtilis S. epidermidis E. coli P. aeruginosa
)
µmol cm−3
)
M. tuberculosis H37RV
4a
4b
4c
4d
4e
4f
4g
4k
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
0.0898
0.3243
0.1933
0.3375
0.7994
0.6999
1.5227
0.8552
3.1021
1.4822
0.2014
0.1530
0.2694
0.3651
1.6875
0.7661
0.1831
0.7954
0.3023
0.1333
0.2887
0.0015
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
4s
0.0898
0.1622
0.0387
0.0422
0.0799
0.0350
0.0190
0.0428
0.0388
0.0371
0.0201
0.1530
0.0673
0.0730
0.0844
0.0383
0.0366
0.0199
0.0378
0.0333
0.0361
0.0449
0.0405
0.0193
0.0422
0.0799
0.0350
0.0761
0.0428
0.0776
0.0371
0.0403
0.3060
0.0337
0.0365
0.0420
0.0383
0.0183
0.0199
0.0378
0.0167
0.0722
0.0189
0.0898 0.1797
0.0811 0.0811
0.0387 0.0387
0.0211 0.0211
0.0799 0.0400
0.0175 0.0350
0.0381 0.0381
0.0855 0.0855
0.0776 0.0776
0.0371 0.0371
0.0806 0.0806
0.1530 0.3060
0.0337 0.0168
0.1460 0.1460
0.0420 0.0420
0.0383 0.0383
0.0183 0.0366
0.0199 0.0199
0.0378 0.0378
0.0333 0.0333
0.0361 0.0361
0.0189 0.0189
4s
4t
4t
4u
4u
Isoniazid
Ciprofoxacin 0.0189
4r (MIC 0.0199 µmol/cm3), and 4t (MIC 0.0167 µmol/
cm3) against S. epidermidis; 4d (MIC 0.0211 µmol/cm3),
4f (MIC 0.0175 µmol/cm3), 4q (MIC 0.0183 µmol/cm3),
and 4r (MIC 0.0199 µmol/cm3) against E. coli; 4d (MIC
0.0211 µmol/cm3), 4 m (MIC 0.0168 µmol/cm3), and 4r
(MIC 0.0199 µmol/cm3) against P. aeruginosa displayed
activity comparable to standard drug.
0.0199 µmol/cm3) against A. niger demonstrated appreciable
antifungal activity. It is appreciable that some of molecules
like 4q, 4t against S. epidermidis; 4f, 4q against E. coli; 4m
against P. aeruginosa displayed a better activity in compari-
son to the standard drug used.
It can be analyzed from antifungal screening that triazoles
with electron withdrawing nitro group on anilide ring dis-
played considerable improvement in antifungal activity as
compared to electron-donating methoxy group. In case of A.
niger, triazoles with 4-fuorophenyl moiety found to possess
a better fungicidal activity than triazole derivatives having
other halogens. It is evident from results that compounds 4f,
4k against C. albicans, and 4j, 4k, 4r against A. niger were
found to exhibit a better inhibitory activity in comparison
to standard drug used.
Results clearly illustrated that compounds possessing
electron withdrawing nitro group on anilide rings exhibited a
better bactericidal activity in comparison to compounds with
electron-donating methoxy group. In most of cases, com-
pounds with 4-bromo substituents on anilide ring displayed
a better inhibitory activity in comparison to compounds with
the other halogen groups.
Results of antifungal screening (Table 3) clearly give a
picture that some of triazole derivatives showed promis-
ing antifungal activity against tested fungal strains. Among
the synthesized triazoles, compounds 4d and 4k exhib-
ited a better antifungal potency against both the fungal
strains used. Compounds 4d (MIC 0.0211 µmol/cm3), 4f
(MIC 0.0175 µmol/cm3), and 4k (MIC 0.0201 µmol/cm3)
against C. albicans; 4d (MIC 0.0211 µmol/cm3), 4j (MIC
0.0185 µmol/cm3), 4k(MIC 0.0201 µmol/cm3), and 4r (MIC
Conclusion
In summary, synthesis of a series of N-aryl-2-(4-substi-
tuted-1H-1,2,3-triazol-1-yl)acetamides 4a–4u were achieved
via one-pot Cu(I) catalyzed click reaction between terminal
alkynes and 2-azido-N-substituted acetamides. Synthesized
1 3

Efcient synthesis, antitubercular and antimicrobial evaluation of 1,4‑disubstituted…
Table 3 In vitro antifungal activity of 1,4-disubstituted 1,2,3-triazoles
13C) were recorded on a 400 MHz BrukerAvance-III spec-
4a–4u
trometer operating at 400 MHz and 100 MHz, respectively,
in DMSO-d6. Chemical shifts (δ) are observed in parts per
million (ppm). Coupling constant (J) values were stated in
Hertz (Hz). High-resolution mass spectra (HRMS) were
scanned on Waters Micromass Q-Tof Micro (ESI) spectrom-
eter. Values were represented in m/z. Ready-made silica gel
plates (SIL G/UV254, ALUGRAM) were used for thin-layer
chromatography (TLC) and spots were visualized under
ultraviolet lamp.
Compound
Minimum inhibitory concentration
(MIC/µmol cm−3
)
C. albicans
A. niger
4a
0.0898
0.0811
0.0387
0.0211
0.0400
0.0175
0.0381
0.0428
0.0388
0.0371
0.0201
0.0765
0.0373
0.0365
0.0422
0.0766
0.0366
0.0398
0.0378
0.0333
0.0361
0.0204
0.0898
0.0405
0.0387
0.0211
0.0400
0.0350
0.0381
0.0428
0.0388
0.0185
0.0201
0.0383
0.0373
0.0730
0.0422
0.0766
0.0366
0.0199
0.0378
0.0333
0.1444
0.0204
4b
4c
4d
4e
4f
General procedure for the synthesis
of N‑aryl‑2‑(4‑substituted‑1H‑1,2,3‑triazol‑1‑yl)‑
acetamides 4a‑4u
4g
4h
4i
4j
Synthesis of 2-bromo-N-substituted acetamides 2a–2g [32]
was carried out by dissolving aromatic amines (1.0 mmol)
1a–1g in 8–15 cm3 dichloromethane, followed by addition
of potassium carbonate (1.5 mmol) as base and stirred the
solution. Afterwards, bromoacetyl bromide (1.2 mmol) was
added dropwise to above stirred solution at 0–5 °C and con-
tinued stirring for 15 min. When reaction was completed, ice
cold water was added, and solid product was precipitated,
fltered, and dried.
4k
4l
4m
4n
4o
4p
4q
4r
4s
For the synthesis of N-aryl-2-(4-substituted-1H-1,2,3-
triazol-1-yl)acetamides 4a–4u, aqueous solution of sodium
azide (3.0 mmol) was added to 2-bromo-N-substituted
acetamides 2a–2g (1.0 mmol) in 7–14 cm3 N,N-dimethyl-
formamide at 25–40 °C and stirred solution for 1 h. After-
wards, terminal alkynes 3a–3c (1.0 mmol) were added to
above solution, followed by the addition of copper sulfate
pentahydrate (0.1 mmol) and sodium ascorbate (0.4 mmol)
and continued stirred the reaction contents at the same tem-
perature for 7–15 h. Progress of reaction was monitored by
TLC at regular intervals. As the reaction was completed,
ice cold water was added to reaction mixture; solid residues
were precipitated, collected by fltration, and washed with
ammonia solution. Crude precipitates were then purifed by
washing with ethyl acetate and dried by applying vacuum
to aford target 1,4-disubstituted 1,2,3-triazoles 4a–4u in
good yield.
4t
4u
Fluconazole
triazole derivatives were evaluated for in vitro antitubercular
potential against Mycobacterium tuberculosis and antimi-
crobial potential against Bacillus subtilis, Staphylococcus
epidermidis, Escherichia coli, Pseudomonas aeruginosa,
Candida albicans, and Aspergillus niger. Compound 4a
overall displayed appreciating antitubercular activity against
M. tuberculosis. Compounds 4d and 4k emerged as potent
antifungal agent than the other triazole derivatives, while
compound 4r showed noteworthy microbicidal activity
against most of the tested strains used.
Experimental
N‑Phenyl‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)acetamide
(4a, C16H14N4O) White solid; yield: 82%; m.p.: 250–254 °C;
All reagents and solvents used in the present work were
commercially available grade and used as received without
further purifcation. Nutrient broth and Sabouraud dextrose
broth used in antimicrobial activity were purchased from
Hi-Media, Mumbai. Melting points of the synthesized com-
pounds were recorded on an Electrothermal Melting Point
apparatus. The FT-IR absorption spectra were scanned on
IR AFFINITY-I FT-IR (SHIMAZDU) spectrometer using
potassium bromide (KBr) powder and wave numbers are
noted in cm−1. Nuclear magnetic resonance spectra (1H and
̄
FT-IR (KBr): =3267 (N–H str.), 3134 (C–H str., triazole
V
ring), 3065 (C–H str., aromatic ring), 2934 (C–H str., ali-
phatic), 1672 (C=O str., amide), 1599, 1547 (C=C str., aro-
matic ring) cm−1; 1H NMR (400 MHz, DMSO-d6): δ=5.42
(s, 2H, NCH2), 7.10 (t, 1H, Ar–H, J = 8.0 Hz), 7.33–7.37
(m, 3H, Ar–H), 7.47 (t, 2H, Ar–H, J=8.0 Hz), 7.63 (d, 2H,
Ar–H, J=8.0 Hz), 7.90 (d, 2H, Ar–H, J=8.0 Hz), 8.62 (s,
1H, C–H triazole), 10.55 (s, 1H, N–H amide) ppm; 13C
NMR (100 MHz, DMSO-d6): δ = 52.7, 119.7, 123.4 (C5
1 3

C. P. Kaushik et al.
triazole), 124.2, 125.6, 128.3, 129.4, 131.2, 138.9, 146.7
(C4 triazole), 164.5 (C=O amide) ppm; HRMS: m/z calcu-
lated for C16H14N4O ([M+H]+) 279.1201, found 279.1249.
calculated for C16H13FN4O ([M + H]+) 297.1107, found
297.1152.
N‑(4‑Chlorophenyl)‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)aceta‑
mide (4e, C16H13ClN4O) White solid; yield: 86%; m.p.: 258–
N‑(4‑Methoxyphenyl)‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)‑
acetamide (4b, C17H16N4O2) White solid; yield: 88%; m.p.:
̄
262 °C; FT-IR (KBr): V =3263 (N–H str.), 3123 (C–H str.,
̄
228–232 °C; FT-IR (KBr): V = 3277 (N–H str.), 3163
triazole ring), 3076 (C–H str., aromatic ring), 2941 (C–H str.,
aliphatic), 1674 (C=O str., amide), 1607, 1543, 1493 (C=C
str., aromatic ring) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ=5.42 (s, 2H, NCH2), 7.33–7.48 (m, 5H, Ar–H), 7.65 (d,
2H, Ar–H, J=8.0 Hz), 7.89 (d, 2H, Ar–H, J=8.0 Hz), 8.62
(s, 1H, C-H triazole), 10.68 (s, 1H, N–H amide) ppm; 13C
NMR (100 MHz, DMSO-d6): δ = 52.8, 121.3, 123.5 (C5
triazole), 125.6, 127.9, 128.3, 129.3, 129.4, 131.2, 137.8,
146.7 (C4 triazole), 164.9 (C=O amide) ppm; HRMS: m/z
calculated for C16H13ClN4O ([M + H]+) 313.0856 (35Cl),
315.0827 (37Cl), found 313.1152 (35Cl), 315.1083 (35Cl).
(C–H str., triazole ring), 3084 (C–H str., aromatic ring),
2951 (C–H str., aliphatic), 1668 (C=O str., amide), 1605,
1547, 1464 (C=C str., aromatic ring), 1244 (C–O asym.
1
str., ether), 1032 (C–O sym. str., ether) cm−1; H NMR
(400 MHz, DMSO-d6): δ = 3.73 (s, 3H, OCH3), 5.37 (s,
2H, NCH2), 6.93 (d, 2H, Ar–H, J = 8.0 Hz), 7.35 (t, 1H,
Ar–H, J=8.0 Hz), 7.47 (t, 2H, Ar–H, J=8.0 Hz), 7.53 (d,
2H, Ar–H, J=8.0 Hz), 7.89 (d, 2H, Ar–H, J=8.0 Hz), 8.61
(s, 1H, C–H triazole), 10.40 (s, 1H, N–H amide) ppm; 13C
NMR (100 MHz, DMSO-d6): δ=52.8, 55.3, 114.5, 121.2,
123.4 (C5 triazole), 125.6, 128.3, 129.4, 131.2, 132.0, 146.6
(C4 triazole), 156.1, 164.1 (C=O amide) ppm; HRMS: m/z
calculated for C17H16N4O2 ([M + H]+) 309.1307, found
309.1350.
N‑(4‑Bromophenyl)‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)‑
acetamide (4f, C16H13BrN4O) White solid; yield: 78%; m.p.:
̄
268–272 °C; FT-IR (KBr): V =3211 (N–H str.), 3155 (C–H
str., triazole ring), 3007 (C–H str., aromatic ring), 2940
(C–H str., aliphatic), 1676 (C=O str., amide), 1609, 1543,
1489 (C=C str., aromatic ring) cm−1; 1H NMR (400 MHz,
DMSO-d6): δ = 5.40 (s, 2H, NCH2), 7.35 (t, 1H, Ar–H,
J=8.0 Hz), 7.47 (t, 2H, Ar–H, J=8.0 Hz), 7.53–7.60 (m,
4H, Ar–H), 7.88 (d, 2H, Ar–H, J = 8.0 Hz), 8.61 (s, 1H,
C–H triazole), 10.67 (s, 1H, N–H amide) ppm; 13C NMR
(100 MHz, DMSO-d6): δ = 52.7, 115.9, 121.7, 123.5 (C5
triazole), 125.6, 128.3, 129.4, 131.2, 132.2, 138.2, 146.4 (C4
triazole), 165.0 (C=O amide) ppm; HRMS: m/z calculated
for C16H13BrN4O ([M + H]+) 357.0351 (79Br), 359.0331
(81Br), found 357.0350 (79Br), 359.0322 (81Br).
N‑(4‑Nitrophenyl)‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)aceta‑
mide (4c, C16H13N5O3) White solid; yield: 81%; m.p.: 264–
̄
268 °C; FT-IR (KBr): V =3302 (N–H str.), 3160 (C–H str.,
triazole ring), 3064 (C–H str., aromatic ring), 2935 (C–H
str., aliphatic), 1703 (C=O str., amide), 1616, 1599, 1568
(C=C str., aromatic ring), 1504 (N–O asym. str., NO2),
1
1344 (N–O sym. str., NO2) cm−1; H NMR (400 MHz,
DMSO-d6): δ = 5.53 (s, 2H, NCH2), 7.39 (t, 1H, Ar–H,
J=8.0 Hz), 7.50 (t, 2H, Ar–H, J=8.0 Hz), 7.88–7.93 (m,
4H, Ar–H), 8.30 (d, 2H, Ar–H, J = 8.0 Hz), 8.65 (s, 1H,
C–H triazole), 11.18 (s, 1H, N–H amide) ppm; 13C NMR
(100 MHz, DMSO-d6): δ=52.8, 119.6, 123.5 (C5 triazole),
125.6, 128.4, 129.3, 131.1, 143.0, 144.9, 146.8 (C4 tria-
zole), 165.8 (C=O amide) ppm; HRMS: m/z calculated for
C16H13N5O3 ([M+H]+) 324.1052, found 324.1096.
N‑(Naphthalen‑1‑yl)‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)aceta‑
mide (4g, C20H16N4O) White solid; yield: 88%; m.p.: 260–
̄
264 °C; FT-IR (KBr): V =3246 (N–H str.), 3132 (C–H str.,
triazole ring), 3049 (C–H str., aromatic ring), 2934 (C–H
str., aliphatic), 1666 (C=O str., amide), 1549, 1470 (C=C
str., aromatic ring) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ=5.61 (s, 2H, NCH2), 7.35 (t, 1H, Ar–H, J=8.0 Hz), 7.45–
7.64 (m, 5H, Ar–H), 7.75 (d, 1H, Ar–H, J=8.0 Hz), 7.82 (d,
1H, Ar–H, J=8.0 Hz), 7.90 (d, 2H, Ar–H, J=8.0 Hz), 7.98
(d, 1H, Ar–H, J=8.0 Hz), 8.20 (d, 1H, Ar–H, J=8.0 Hz),
8.67 (s, 1H, C–H triazole), 10.49 (s, 1H, N–H amide) ppm;
13C NMR (100 MHz, DMSO-d6): δ = 52.5, 122.1, 123.1,
123.6 (C5 triazole), 125.6, 126.1, 126.2, 126.5, 126.7, 128.0,
128.3, 128.7, 129.4, 131.2, 133.2, 134.2, 146.7 (C4 tria-
zole), 165.6 (C=O amide) ppm; HRMS: m/z calculated for
C20H16N4O ([M+H]+) 329.1358, found 329.1410.
N‑(4‑Fluorophenyl)‑2‑(4‑phenyl‑1H‑1,2,3‑triazol‑1‑yl)aceta‑
mide (4d, C16H13FN4O) White solid; yield: 85%; m.p.: 246–
̄
250 °C; FT-IR (KBr): V =3283 (N–H str.), 3135 (C–H str.,
triazole ring), 3086 (C–H str., aromatic ring), 2938 (C–H
str., aliphatic), 1670 (C=O str., amide), 1616, 1558 (C=C
str., aromatic ring) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ = 5.40 (s, 2H, NCH2), 7.18–7.22 (m, 2H, Ar–H), 7.35
(t, 1H, Ar–H, J = 8.0 Hz), 7.47 (t, 2H, Ar–H, J= 8.0 Hz),
7.62–7.64 (m, 2H, Ar–H), 7.89 (d, 2H, Ar–H, J=8.0 Hz),
8.62 (s, 1H, C–H triazole), 10.61 (s, 1H, N–H amide) ppm;
13C NMR (100 MHz, DMSO-d6): δ = 52.8, 116.0 (d, 2C,
Ar–C, J = 22.0 Hz), 121.6 (d, 2C, Ar–C, J = 8.0 Hz),
123.5 (C5 triazole), 125.6, 128.3, 129.4, 131.2, 135.3 (d,
2C, Ar–C, J = 3.0 Hz), 146.7 (C4 triazole), 158.7 (d, 1C,
Ar–C, J=239.0 Hz), 164.6 (C=O amide) ppm; HRMS: m/z
N‑Phenyl‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]acetamide
(4h, C17H16N4O) White solid; yield: 83%; m.p.: 262–266 °C;
1 3

Efcient synthesis, antitubercular and antimicrobial evaluation of 1,4‑disubstituted…
̄
(C–H str., aliphatic), 1676 (C=O str., amide), 1614, 1545,
FT-IR (KBr): V =3269 (N–H str.), 3163 (C–H str., triazole
ring), 3094 (C–H str., aromatic ring), 2924 (C–H str., ali-
phatic), 1676 (C=O str., amide), 1599, 1543, 1499 (C=C
str., aromatic ring) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ=2.30 (s, 3H, CH3), 5.37 (s, 2H, NCH2), 7.10 (t, 1H, Ar–H,
J = 8.0 Hz), 7.27 (d, 2H, Ar–H, J = 8.0 Hz), 7.34 (t, 2H,
Ar–H, J=8.0 Hz), 7.60 (d, 2H, Ar–H, J=8.0 Hz), 7.77 (d,
2H, Ar–H, J=8.0 Hz), 8.54 (s, 1H, C-H triazole), 10.52 (s,
1H, N–H amide) ppm; 13C NMR (100 MHz, DMSO-d6):
δ = 21.2, 52.8, 119.7, 123.1 (C5 triazole), 124.3, 125.5,
128.3, 129.3, 129.9, 137.6, 138.9, 146.7 (C4 triazole),
164.6 (C=O amide) ppm; HRMS: m/z calculated for
C17H16N4O ([M+H]+) 293.1358, found 293.1404.
1466 (C=C str., aromatic ring) cm−1; 1H NMR (400 MHz,
DMSO-d6): δ = 2.34 (s, 3H, CH3), 5.38 (s, 2H, NCH2),
7.17–7.22 (m, 2H, Ar–H), 7.27 (d, 2H, Ar–H, J=8.0 Hz),
7.61–7.65 (m, 2H, Ar–H), 7.77 (d, 2H, Ar–H, J=8.0 Hz),
8.54 (s, 1H, C–H triazole), 10.59 (s, 1H, N–H amide) ppm;
13C NMR (100 MHz, DMSO-d6): δ=21.2, 52.7, 116.0 (d,
2C, Ar–C, J = 22.0 Hz), 121.5 (d, 2C, Ar–C, J = 8.0 Hz),
123.0 (C5 triazole), 125.4, 128.3, 129.9, 135.3 (d, 2C, Ar–C,
J=3.0 Hz), 137.6, 146.7 (C4 triazole), 158.7 (d, 1C, Ar–C,
J=239.0 Hz), 164.6 (C=O amide) ppm; HRMS: m/z calcu-
lated for C17H15FN4O ([M+H]+) 311.1263, found 311.1408.
N‑(4‑Chlorophenyl)‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]aceta‑
mide (4l, C17H15ClN4O) White solid; yield: 86%; m.p.: 268–
N‑(4‑Methoxyphenyl)‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]‑
acetamide (4i, C18H18N4O2) White solid; yield: 81%; m.p.:
̄
272 °C; FT-IR (KBr): V =3269 (N–H str.), 3128 (C–H str.,
̄
triazole ring), 3074 (C–H str., aromatic ring), 2914 (C–H str.,
aliphatic), 1670 (C=O str., amide), 1610, 1547, 1493 (C=C
str., aromatic ring) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ = 2.34 (s, 3H, CH3), 5.39 (s, 2H, NCH2), 7.27 (d, 2H,
Ar–H, J=8.0 Hz), 7.41 (d, 2H, Ar–H, J=8.0 Hz), 7.64 (d,
2H, Ar–H, J=8.0 Hz), 7.77 (d, 2H, Ar–H, J=8.0 Hz), 8.55
(s, 1H, C–H triazole), 10.67 (s, 1H, N–H amide) ppm; 13C
NMR (100 MHz, DMSO-d6): δ = 21.2, 52.5, 121.3, 123.1
(C5 triazole), 125.6, 127.9, 128.4, 129.3, 130.0, 137.6,
137.8, 146.7 (C4 triazole), 164.9 (C=O amide) ppm; HRMS:
m/z calculated for C17H15ClN4O ([M+H]+) 327.1013 (35Cl),
329.0983 (37Cl), found 327.1014 (35Cl), 329.0985 (37Cl).
250–254 °C; FT-IR (KBr): V =3279 (N–H str.), 3166 (C–H
str., triazole ring), 3064 (C–H str., aromatic ring), 2912
(C–H str., aliphatic), 1678 (C=O str., amide), 1607, 1543,
1462 (C=C str., aromatic ring), 1244 (C–O asym. str., ether),
1034 (C–O sym. str., ether) cm−1; H NMR (400 MHz,
1
DMSO-d6): δ=2.34 (s, 3H, CH3), 3.73 (s, 3H, OCH3), 5.35
(s, 2H, NCH2), 6.92 (d, 2H, Ar–H, J=8.0 Hz), 7.27 (d, 2H,
Ar–H, J=8.0 Hz), 7.53 (d, 2H, Ar–H, J=8.0 Hz), 7.77 (d,
2H, Ar–H, J=8.0 Hz), 8.54 (s, 1H, C-H triazole), 10.39 (s,
1H, N–H amide) ppm; 13C NMR (100 MHz, DMSO-d6):
δ = 21.2, 52.7, 55.6, 114.5, 121.3, 123.0 (C5 triazole),
125.5, 128.4, 129.8, 132.0, 137.5, 146.6 (C4 triazole),
156.1, 164.1 (C=O amide) ppm; HRMS: m/z calculated for
C18H18N4O2 ([M+H]+) 323.1463, found 323.1509.
N‑(4‑Bromophenyl)‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]‑
acetamide (4m, C17H15BrN4O) White solid; yield: 85%; m.p.:
̄
276–280 °C; FT-IR (KBr): V =3265 (N–H str.), 3157 (C–H
N‑(4‑Nitrophenyl)‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]aceta‑
mide (4j, C17H15N5O3) White solid; yield: 87%; m.p.: 276–
str., triazole ring), 3071 (C–H str., aromatic ring), 2941
(C–H str., aliphatic), 1676 (C=O str., amide), 1607, 1543,
1491 (C=C str., aromatic ring) cm−1; 1H NMR (400 MHz,
DMSO-d6): δ = 2.34 (s, 3H, CH3), 5.39 (s, 2H, NCH2),
7.27 (d, 2H, Ar–H, J=8.0 Hz), 7.52–7.60 (m, 4H, Ar–H),
7.77 (d, 2H, Ar–H, J=8.0 Hz), 8.54 (s, 1H, C–H triazole),
10.67 (s, 1H, N–H amide) ppm; 13C NMR (100 MHz,
DMSO-d6): δ = 21.3, 52.8, 115.9, 121.7, 123.1 (C5 tria-
zole), 125.6, 128.4, 130.0, 132.2, 137.6, 138.3, 146.8 (C4
triazole), 164.7 (C=O amide) ppm; HRMS: m/z calculated
for C17H15BrN4O ([M + H]+) 371.0507 (79Br), 373.0487
(81Br), found 371.0509 (79Br), 373.0490 (81Br).
̄
280 °C; FT-IR (KBr): V =3277 (N–H str.), 3185 (C–H str.,
triazole ring), 3064 (C–H str., aromatic ring), 2935 (C–H str.,
aliphatic), 1701 (C=O str., amide), 1618, 1566, 1468 (C=C
str., aromatic ring), 1504 (N–O asym. str., NO2), 1344 (N–O
sym. str., NO2) cm−1; H NMR (400 MHz, DMSO-d6):
1
δ = 2.34 (s, 3H, CH3), 5.48 (s, 2H, NCH2), 7.28 (d, 2H,
Ar–H, J=8.0 Hz), 7.77 (d, 2H, Ar–H, J=8.0 Hz), 7.86 (d,
2H, Ar–H, J=8.0 Hz), 8.27 (d, 2H, Ar–H, J=8.0 Hz), 8.55
(s, 1H, C–H triazole), 11.14 (s, 1H, N–H amide) ppm; 13C
NMR (100 MHz, DMSO-d6): δ = 21.2, 52.8, 119.6, 123.0
(C5 triazole), 125.6, 125.6, 128.2, 123.0, 137.7, 143.1,
145.0, 146.8 (C4 triazole), 165.8 (C=O amide) ppm; HRMS:
m/z calculated for C17H15N5O3 ([M+H]+) 338.1208, found
338.1254.
N‑(Naphthalen‑1‑yl)‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]‑
acetamide (4n, C21H18N4O) White solid; yield: 78%; m.p.:
̄
266–270 °C; FT-IR (KBr): V =3260 (N–H str.), 3166 (C–H
str., triazole ring), 3059 (C–H str., aromatic ring), 2934 (C–H
str., aliphatic), 1666 (C=O str., amide), 1549, 1466 (C=C
str., aromatic ring) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ = 2.34 (s, 3H, CH3), 5.59 (s, 2H, NCH2), 7.28 (d, 2H,
Ar–H, J = 8.0 Hz), 7.51–7.64 (m, 3H, Ar–H), 7.74–7.83
N‑(4‑Fluorophenyl)‑2‑[4‑(p‑tolyl)‑1H‑1,2,3‑triazol‑1‑yl]‑
acetamide (4k, C17H15FN4O) White solid; yield: 80%; m.p.:
̄
254–258 °C; FT-IR (KBr): V =3283 (N–H str.), 3177 (C–H
str., triazole ring), 3065 (C–H str., aromatic ring), 2943
1 3

C. P. Kaushik et al.
(m, 4H, Ar–H), 7.98 (d, 1H, Ar–H, J = 8.0 Hz), 8.20 (d,
1H, Ar–H, J=8.0 Hz), 8.60 (s, 1H, C–H triazole), 10.48 (s,
1H, N–H amide) ppm; 13C NMR (100 MHz, DMSO-d6):
δ = 21.2, 52.5, 122.0, 123.1 (C5 triazole), 123.1, 125.6,
126.0, 126.2, 126.5, 126.7, 128.0, 128.5, 128.7, 129.9, 133.2,
134.2, 137.3, 146.7 (C4 triazole), 165.6 (C=O amide) ppm;
HRMS: m/z calculated for C21H18N4O ([M+H]+) 343.1514,
found 343.1562.
3148 (C–H str., triazole ring), 3084 (C–H str., aromatic
ring), 2957 (C–H str., aliphatic), 1701 (C=O str., amide),
1616, 1564 (C=C str., aromatic ring), 1501 (N–O asym.
1
str., NO2), 1342 (N–O sym. str., NO2) cm−1; H NMR
(400 MHz, DMSO-d6): δ=5.51 (s, 2H, NCH2), 7.16–7.20
(m, 1H, Ar–H), 7.49–7.54 (m, 1H, Ar–H), 7.69–7.75 (m, 2H,
Ar–H), 7.86 (d, 2H, Ar–H, J=8.0 Hz), 8.26 (d, 2H, Ar–H,
J=8.0 Hz), 8.70 (s, 1H, C-H triazole), 11.15 (s, 1H, N–H
amide) ppm; 13C NMR (100 MHz, DMSO-d6): δ = 52.7,
112.2 (d, 1C, Ar–C, J = 23.0 Hz), 115.0 (d, 1C, Ar–C,
J=21.0 Hz), 119.6, 121.7 (d, 1C, Ar–C, J=3.0 Hz), 124.2
(C5 triazole), 125.6, 131.5 (d, 1C, Ar–C, J=9.0 Hz), 133.5
(d, 1C, Ar–C, J=9.0 Hz), 143.1, 144.9, 145.7 (d, 1C, Ar–C,
J=3.0 Hz, C4 triazole), 163.1 (d, 1C, Ar–C, J=242.0 Hz),
165.7 (C=O amide) ppm; HRMS: m/z calculated for
C16H12FN5O3 ([M+H]+) 342.0958, found 342.1000.
2‑[4‑(3‑Fluorophenyl)‑1H‑1,2,3‑triazol‑1‑yl]‑N‑phenylacet‑
amide (4o, C16H13FN4O) White solid; yield: 80%; m.p.:
̄
258–262 °C; FT-IR (KBr): V =3263 (N–H str.), 3132 (C–H
str., triazole ring), 3069 (C–H str., aromatic ring), 2937
(C–H str., aliphatic), 1668 (C=O str., amide), 1593, 1549,
1485 (C=C str., aromatic ring) cm−1; 1H NMR (400 MHz,
DMSO-d6): δ = 5.42 (s, 2H, NCH2), 7.10 (t, 1H, Ar–H,
J=8.0 Hz), 7.17–7.21 (m, 1H, Ar–H), 7.35 (t, 2H, Ar–H,
J=8.0 Hz), 7.49–7.55 (m, 1H, Ar–H), 7.61 (d, 2H, Ar–H,
J=8.0 Hz), 7.70–7.76 (m, 2H, Ar–H), 8.70 (s, 1H, C–H tria-
zole), 10.54 (s, 1H, N–H amide) ppm; 13C NMR (100 MHz,
DMSO-d6): δ = 52.8, 112.2 (d, 1C, Ar–C, J = 23.0 Hz),
115.0 (d, 1C, Ar–C, J=21.0 Hz), 119.6, 121.6 (d, 1C, Ar–C,
J=3.0 Hz), 124.2 (C5 triazole), 124.3, 129.4, 131.5 (d, 1C,
Ar–C, J=9.0 Hz), 133.6 (d, 1C, Ar–C, J=9.0 Hz), 138.8,
145.6 (d, 1C, Ar–C, J=3.0 Hz, C4 triazole), 163.1 (d, 1C,
Ar–C, J=241.0 Hz), 164.5 (C=O amide) ppm; HRMS: m/z
calculated for C16H13FN4O ([M + H]+) 297.1107, found
297.1155.
N‑(4‑Fluorophenyl)‑2‑[4‑(3‑fluorophenyl)‑1H‑1,2,3‑tria‑
zol‑1‑yl]acetamide (4r, C16H12F2N4O) White solid; yield:
̄
79%; m.p.: 246–250 °C; FT-IR (KBr): V =3260 (N–H str.),
3136 (C–H str., triazole ring), 3067 (C–H str., aromatic
ring), 2937 (C–H str., aliphatic), 1672 (C=O str., amide),
1614, 1549, 1481 (C=C str., aromatic ring) cm−1; 1H NMR
(400 MHz, DMSO-d6): δ=5.40 (s, 2H, NCH2), 7.17–7.22
(m, 3H, Ar–H), 7.49–7.55 (m, 1H, Ar–H), 7.61–7.75 (m,
4H, Ar–H), 8.69 (s, 1H, C–H triazole), 10.61 (s, 1H, N–H
amide) ppm; 13C NMR (100 MHz, DMSO-d6): δ = 52.8,
112.8 (d, 1C, Ar–C, J = 23.0 Hz), 115.0 (d, 1C, Ar–C,
J = 21.0 Hz), 116.0 (d, 2C, Ar–C, J = 22.0 Hz), 121.6 (d,
1C, Ar–C, J = 8.0 Hz), 121.6 (d, 1C, Ar–C, J = 3.0 Hz),
124.2 (C5 triazole), 131.5 (d, 1C, Ar–C, J=8.0 Hz), 133.5
(d, 1C, Ar–C, J=9.0 Hz), 135.2 (d, 1C, Ar–C, J=3.0 Hz),
145.6 (d, 1C, Ar–C, J=2.0 Hz, C4 triazole), 158.7 (d, 1C,
Ar–C, J = 239.0 Hz), 163.1 (d, 1C, Ar–C, J = 242.0 Hz),
164.5 (C=O amide) ppm; HRMS: m/z calculated for
C16H12F2N4O ([M+H]+) 315.1013, found 315.1063.
2‑[4‑(3‑Fluorophenyl)‑1H‑1,2,3‑triazol‑1‑yl]‑N‑(4‑methoxy‑
phenyl)acetamide (4p, C17H15FN4O2) White solid; yield:
̄
77%; m.p.: 276-280 °C; FT-IR (KBr): V =3265 (N–H str.),
3155 (C–H str., triazole ring), 3007 (C–H str., aromatic
ring), 2912 (C–H str., aliphatic), 1672 (C=O str., amide),
1608, 1543, 1489 (C=C str., aromatic ring), 1229 (C–O
1
asym. str., ether), 1076 (C–O sym. str., ether) cm−1; H
NMR (400 MHz, DMSO-d6): δ=3.73 (s, 3H, OCH3), 5.38
(s, 2H, NCH2), 6.92 (d, 2H, Ar–H, J=8.0 Hz), 7.16–7.20
(m, 1H, Ar–H), 7.49–7.54 (m, 3H, Ar–H), 7.69–7.76 (m,
2H, Ar–H), 8.69 (s, 1H, C-H triazole), 10.41 (s, 1H, N–H
amide) ppm; 13C NMR (100 MHz, DMSO-d6): δ = 53.0,
55.6, 112.2 (d, 1C, Ar–C, J = 23.0 Hz), 114.5, 115.0
(d, 1C, Ar–C, J = 21.0 Hz), 121.3, 121.6 (d, 1C, Ar–C,
J=2.0 Hz), 124.2 (C5 triazole), 124.3, 131.5 (d, 1C, Ar–C,
J=8.0 Hz), 131.9, 133.6 (d, 1C, Ar–C, J=8.0 Hz), 145.6
(d, 1C, Ar–C, J=3.0 Hz, C4 triazole), 156.1, 163.1 (d, 1C,
Ar–C, J=242.0 Hz), 164.0 (C=O amide) ppm; HRMS: m/z
calculated for C17H15FN4O2 ([M + H]+) 327.1213, found
327.1258.
N‑(4‑Chlorophenyl)‑2‑[4‑(3‑fluorophenyl)‑1H‑1,2,3‑tria‑
zol‑1‑yl]acetamide (4s, C16H12ClFN4O) White solid; yield:
̄
75%; m.p.: 264–268 °C; FT-IR (KBr): V =3267 (N–H str.),
3159 (C–H str., triazole ring), 3078 (C–H str., aromatic
ring), 2995 (C–H str., aliphatic), 1676 (C=O str., amide),
1610, 1549, 1489 (C=C str., aromatic ring) cm−1; 1H NMR
(400 MHz, DMSO-d6): δ=5.42 (s, 2H, NCH2), 7.16–7.21
(m, 1H, Ar–H), 7.41 (d, 2H, Ar–H, J=8.0 Hz), 7.49–7.54
(m, 1H, Ar–H), 7.64 (d, 2H, Ar–H, J=8.0 Hz), 7.69–7.75
(m, 2H, Ar–H), 8.69 (s, 1H, C–H triazole), 10.69 (s, 1H,
N–H amide) ppm; 13C NMR (100 MHz, DMSO-d6):
δ = 52.5, 112.2 (d, 1C, Ar–C, J = 23.0 Hz), 115.0 (d, 1C,
Ar–C, J=21.0 Hz), 121.3, 121.6 (d, 1C, Ar–C, J=3.0 Hz),
124.2 (C5 triazole), 127.9, 129.3, 131.5 (d, 1C, Ar–C,
J=9.0 Hz), 133.5 (d, 1C, Ar–C, J=8.0 Hz), 137.8, 145.6
(d, 1C, Ar–C, J=2.0 Hz, C4 triazole), 163.0 (d, 1C, Ar–C,
2‑[4‑(3‑Fluorophenyl)‑1H‑1,2,3‑triazol‑1‑yl]‑N‑(4‑nitrophe‑
nyl)acetamide (4q, C16H12FN5O3) White solid; yield: 88%;
̄
m.p.: 240–244 °C; FT-IR (KBr): V = 3308 (N–H str.),
1 3

Efcient synthesis, antitubercular and antimicrobial evaluation of 1,4‑disubstituted…
J = 247.0 Hz), 164.7 (C=O amide) ppm; HRMS: m/z cal-
culated for C16H12ClFN4O ([M + H]+) 331.0762 (35Cl),
333.0732 (37Cl), found 331.0766 (35Cl), 333.0736 (37Cl).
of µmol/cm3 and isoniazid was used as reference drug.
Lowenstein–Jensen (L. J.) was used as nutrient medium to
grow and dilute the suspension of compounds for the test.
Inoculum size for test strain was adjusted to 1 mg/cm3.
DMSO was used as diluent/vehicle to get desired concen-
tration of synthesized compounds to test upon the standard
bacterial strain. Each synthesized drug was diluted obtaining
2000 µg/cm3 concentration, as a stock solution.
N‑(4‑Bromophenyl)‑2‑[4‑(3‑fluorophenyl)‑1H‑1,2,3‑tria‑
zol‑1‑yl]acetamide (4t, C16H12BrFN4O) White solid; yield:
̄
85%; m.p.: 250–254 °C; FT-IR (KBr): V =3254 (N–H str.),
3132 (C–H str., triazole ring), 3063 (C–H str., aromatic
ring), 2941 (C–H str., aliphatic), 1668 (C=O str., amide),
1618, 1549, 1479 (C=C str., aromatic ring) cm−1; 1H NMR
(400 MHz, DMSO-d6): δ=5.42 (s, 2H, NCH2), 7.16–7.21
(m, 1H, Ar–H), 7.49–7.60 (m, 5H, Ar–H), 7.69–7.75 (m,
2H, Ar–H), 8.69 (s, 1H, C–H triazole), 10.69 (s, 1H, N–H
amide) ppm; 13C NMR (100 MHz, DMSO-d6): δ = 52.7,
112.2 (d, 1C, Ar–C, J = 23.0 Hz), 115.0 (d, 1C, Ar–C,
J=21.0 Hz), 115.9, 121.7 (d, 1C, Ar–C, J=4.0 Hz), 121.7,
124.2 (C5 triazole), 131.5 (d, 1C, Ar–C, J=8.0 Hz), 132.2,
133.5 (d, 1C, Ar–C, J=8.0 Hz), 138.2, 145.6 (d, 1C, Ar–C,
J=3.0 Hz, C4 triazole), 163.1 (d, 1C, Ar–C, J=242.0 Hz),
164.8 (C=O amide) ppm; HRMS: m/z calculated for
C16H12BrFN4O ([M + H]+) 375.0257 (79Br), 377.0236
(81Br), found 375.0252 (79Br), 377.0232 (81Br).
Following steps were taken to precede
antitubercular activity
Primary screen: in primary screening, 500 µg/cm3, 250 µg/
cm3, and 125 µg/cm3 concentrations of the synthesized
compounds were taken. The active synthesized compounds
found in this primary screening were further tested in a sec-
ond set of dilution against the tested strain.
Secondary screen: the compounds found active in pri-
mary screening were similarly diluted to obtain 100 µg/cm3,
50 µg/cm3, 25 µg/cm3, 12.5 µg/cm3, 6.250 µg/cm3, 3.125 µg/
cm3, and 1.562 µg/cm3 concentrations.
Reading result: the highest dilution showing at least
99% inhibition is taken as MIC. The result of this is much
afected by the size of the inoculum. The test mixture should
contain 108 organism/cm3.
2 ‑ [ 4 ‑ ( 3 ‑ F l u o r o p h e n y l ) ‑ 1 H‑ 1 , 2 , 3 ‑ t r i a z o l ‑ 1 ‑ y l ] ‑
N‑(naphthalen‑1‑yl)acetamide (4u, C20H15FN4O) White
̄
solid; yield: 87%; m.p.: 258–262 °C; FT-IR (KBr): V =3258
The standard drugs: the Standard strain M. tuberculosis,
H37RV, was tested with each new batch of medium. The rec-
ommended drug concentration was 0.2 mg/cm3 for isoniazid.
(N–H str.), 3152 (C–H str., triazole ring), 3051 (C–H str.,
aromatic ring), 2937 (C–H str., aliphatic), 1670 (C=O str.,
amide), 1553, 1481 (C=C str., aromatic ring) cm−1; 1H NMR
(400 MHz, DMSO-d6): δ=5.63 (s, 2H, NCH2), 7.16–7.21
(m, 1H, Ar–H), 7.49–7.64 (m, 4H, Ar–H), 7.71–7.83 (m,
4H, Ar–H), 7.97 (d, 1H, Ar–H, J = 8.0 Hz), 8.21 (d, 1H,
Ar–H, J = 8.0 Hz), 8.76 (s, 1H, C–H triazole), 10.55 (s,
1H, N–H amide) ppm; 13C NMR (100 MHz, DMSO-d6):
δ = 52.6, 112.2 (d, 1C, Ar–C, J = 23.0 Hz), 115.0 (d, 1C,
Ar–C, J=21.0 Hz), 121.7 (d, 1C, Ar–C, J=3.0 Hz), 122.1,
123.1, 124.3 (C5 triazole), 126.0, 126.2, 126.5, 126.7, 128.0,
128.7, 131.5 (d, 1C, Ar–C, J=8.0 Hz), 133.2, 133.6 (d, 1C,
Ar–C, J = 9.0 Hz), 134.2, 145.6 (d, 1C, Ar–C, J= 3.0 Hz,
C4 triazole), 163.1 (d, 1C, Ar–C, J=242.0 Hz), 165.5 (C=O
amide) ppm; HRMS: m/z calculated for C20H15FN4O
([M+H]+) 347.1213, found 347.1307.
General procedure for in vitro antimicrobial activity
All the synthesized triazole derivatives 4a–4u were exam-
ined for their in vitro antimicrobial activity against two
Gram-positive bacterial strains, i.e., B. subtilis (MTCC
441) and S. epidermidis (MTCC 6880), two Gram-negative
bacterial strains, i.e., E. coli (MTCC 1652) and P. aerugi-
nosa (MTCC 424), and two fungal strains, i.e., C. albicans
(MTCC 183) and A. niger (MTCC 8189) by the serial dilu-
tion technique [33]. Ciprofoxacin and fuconazole were used
as reference drugs against bacteria and fungi, respectively.
Acknowledgements Authors are highly thankful to University Grants
Commission, New Delhi, for fnancial assistance.
General procedure for in vitro antitubercular
activity
References
All synthesized triazole derivatives 4a–4u were evaluated
for in vitro antitubercular activity against bacterial strain
M. tuberculosis H37RV (MTCC 200) by Lowenstein–Jensen
(L. J.) slope method in the Microcare Laboratory and TRC,
Surat, Gujrat.
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