Novel 1,2,3-triazolo phosphonate derivatives as potential antibacterial agents

Article abstract of DOI:10.1002/jhet.4230

We describe the synthesis, characterization, and in vitro antibacterial evaluation of a library of novel compounds based on 1,2,3-triazolo phosphonate framework along with the evaluation of DNA gyrase inhibitory potential of a promising molecule in silico

Full text of DOI:10.1002/jhet.4230

Received: 27 November 2020
DOI: 10.1002/jhet.4230
Revised: 4 January 2021
Accepted: 18 January 2021
A R T I C L E
Novel 1,2,3-triazolo phosphonate derivatives as potential
antibacterial agents
1
1
2
Jhonsee Rani Telu | Naveen Kuntala | Kavitha Kankanala
|
3
2
1
Venkanna Banothu | Sarbani Pal
| Jaya Shree Anireddy
1
Center for Chemical Sciences and
Abstract
Technology, Institute of Science and
Technology, Jawaharlal Nehru
Technological University Hyderabad,
Hyderabad, India
We describe the synthesis, characterization, and in vitro antibacterial evalua-
tion of a library of novel compounds based on 1,2,3-triazolo phosphonate
framework along with the evaluation of DNA gyrase inhibitory potential of a
promising molecule in silico. Preparation of these compounds was carried out
via a multistep sequence comprising of the Abramov reaction followed by the
Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) as the key steps. Various
α-hydroxyphosphonate derivatives containing either a secondary or tertiary
alcohol at the α position were prepared. When screened for their antibacterial
activities in vitro using a Gram-positive (Staphylococcus aureus) and three
Gram-negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas
aeruginosa) strains, majority of these derivatives exhibited reasonable to good
effects with the analogue 5k being active against all the strains. The SAR anal-
ysis indicated that the activity was influenced by the position of the
α-hydroxyphosphonate moiety as well as the substituent present on the ben-
zene ring attached to the 1,2,3-triazole ring. Moreover, the compound 5k
showed strong interactions with the DNA active site when docked into the
DNA gyrase in silico. Thus, the 1,2,3-triazolo phosphonate derivative 5k
appeared to be a novel and promising hit molecule that deserves further study
as a potential antibacterial agent.
2
Department of Chemistry, MNR
Degree & PG College, Hyderabad, India
3
Center for Biotechnology, IST, JNTUH,
Hyderabad, India
Correspondence
Sarbani Pal, Department of Chemistry,
MNR Degree & PG College, Kukatpally,
Hyderabad, India.
Email: sarbani277@yahoo.com
Jaya Shree Anireddy, Center for Chemical
Sciences and Technology, Institute of
Science and Technology, Jawaharlal
Nehru Technological University
Hyderabad, Kukatpally, Hyderabad-
500085, India.
E-mail: jayashreeanireddy@gmail.com
Funding information
DST-INSPIRE, New Delhi, India
1
| INTRODUCTION
quinoline indicated that a combination of a N-
heterocyclic framework with the phosphonate moiety in
a single molecular entity is beneficial for activities espe-
cially against bacteria [5]. Indeed, molecules (B, Figure 1)
containing the 1,2,3-triazole and phosphonate moieties
showed antibacterial effects in addition to the cytotoxic
activities [9]. Apart from involving in the important
interactions with the target enzyme, the phosphonate
antibiotics are known to be capable of hijacking the
glycerol-3-phosphate and glucose-6-phosphate importers
expressed by many bacterial species [10].
The organophosphorus compounds have found enor-
mous applications in medicinal chemistry in addition to
synthetic chemistry as well as agriculture and plastic
industry [1–3]. For example, the α-hydroxyphosphonates,
a common class of organophosphorus derivatives, were
explored for various biological activities [4–8], including
antibacterial effects. In particular, the α-hydroxyphospho-
nates (A, Figure 1) derived from 2-chloroquinolin-
3
-carbaldehyde showed antibacterial activities comparable
to the known antibiotic streptomycin [7]. Furthermore,
the in vitro antibacterial and antifungal activities of
α-hydroxyphosphonate derivatives of tetrazolo[1,5-a]
The triazole moiety (a bioisostere of peptide) on the
other hand is a well-explored framework for the identifi-
cation of new and potent antibacterial agents [11–13].
J Heterocyclic Chem. 2021;58:969–982.
wileyonlinelibrary.com/journal/jhet
© 2021 Wiley Periodicals LLC.
969

970
TELU ET AL.
protein in our in silico studies. Herein, we report the syn-
thesis, characterization, and in vitro antibacterial screen-
ing of a library of compounds based on template C along
with the evaluation of DNA gyrase inhibitory potential of
a
promising molecule in silico. Notably, while
α-hydroxyphosphonates containing a secondary alcohol at
the α position is common in the literature, the compounds
containing tertiary alcohol at the same position are rather
scarce. Nevertheless, to the best of our knowledge, the
preparation and pharmacological assessment of
1,2,3-triazolo phosphonate derivatives related to C have not
been explored earlier.
2
2
| RESULTS AND DISCUSSION
.1 | Chemistry
FIGURE 1 Compounds (A and B) containing an N-
heterocyclic framework and the phosphonate moiety and the newly
designed template C [Colour figure can be viewed at
wileyonlinelibrary.com]
The preparation of target molecules was undertaken via a
multistep sequence using the Cu(I)-catalyzed azide–
alkyne cycloaddition (CuAAC) [24] as the main step
(Scheme 1).
Due to our continuing interest on triazole-based
antibacterial agents [14–16], we explored the novel tem-
plate (C, Figure 1) containing 1,2,3-triazole core and the
hydroxyphosphonate moiety to find new bioactive com-
pounds possessing potential antibacterial properties. Our
current initiative was further prompted by the fact that
the discovery and development of new antibacterial
agents with novel chemical scaffolds is one of the key
approaches to combat infections due to drug-resistant
strains [17,18]. Moreover, since the DNA gyrase (one of
the validated targets for the identification of antibacterial
agents) has been explored [19–23] to tackle the problem
of antibiotic-resistant bacteria, we aimed to target this
One of the required substrates, that is, the terminal
alkyne (3), was prepared as shown in Scheme 1. Thus,
commercially available, appropriately substituted hydrox-
ybenzaldehyde derivatives (1) were O-propargylated to
give the corresponding terminal alkyne (2) that on
Abramov reaction with the mixture of dimethyl-
phosphite, MgCl , and Et N under neat reaction condi-
2
3
tions afforded the desired α-hydroxyphosphonate
derivatives (3) [25]. The organic azides (4) were synthe-
sized from the primary amines via a known procedure
SCHEME 1 Preparation of
compounds (5) based on 1,2,3-triazolo
phosphonate framework (C)

TELU ET AL.
971
TABLE 1 Target compounds synthesized
were due to the OH and the hydrogen at α to the PO
13
(
OCH ) group. The C signals appeared near 63.0, 69.4,
3 2
13
and 119.7 ppm in the C NMR spectra were due to the
OMe (aryl), OCH , and C-5 of the triazole ring, respec-
2
tively, whereas the signals at 55.9 and 53.8 ppm were due
to the PO(OCH3)2 moiety. The signal appeared at
71.0 ppm was due to the CH(OH) moiety. The pres-
ence of PO(OCH ) group was further confirmed by the
3
2
31
signal near δ 26 in the P NMR spectra.
Alkyne 3
Azide 4;
2
2
.2 | Biology
Product 5;
%yield
1
2
a
Ar =
a; o-NO
b; m-NO
c; o-MeOC
d; m-MeOC
R
R
.2.1 | Antibacterial activities
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
2
C
6
H
4
H
H
5a; 90
5b; 80
5c; 81
5d; 85
5e; 90
5f; 85
5g; 80
5h; 78
5i; 81
5j; 80
5k; 78
5l; 80
5m; 80
5n; 80
5o; 90
5p; 90
5q; 90
5r; 90
5s; 90
2
C
6
H
4
H
H
Having prepared a library of new compounds based on
the 1,2,3-triazolo phosphonate framework (C), (Figure 1)
all were tested for their antibacterial effects using a
Gram-positive (Staphylococcus aureus) and three Gram-
negative (Escherichia coli, Klebsiella pneumoniae, and
Pseudomonas aeruginosa) strains. The assay was per-
formed via an agar-well diffusion method [27–29] where
perfloxacin was included as a positive control. The out-
come (Table 2) suggested that while most of the com-
pounds showed activities, the compounds 5k, 5l, and 5q
showed better activity than the others against S. aureus
6
H
4
H
H
6
H
4
H
H
e; p-MeOC
6
H
4
H
H
a
b
d
e
a
b
c
d
e
a
b
c
d
e
H
H
H
H
H
H
H
H
H
Me
Me
Me
Me
Me
H
H
(
+ve), whereas 5b, 5c, 5k, 5p, 5r, and 5s showed good
H
activity against E. coli (−ve). Compounds 5b and 5k
showed some mediocre activity against K. pneumoniae
H
H
(−ve), whereas 5l showed good activity against
OMe
OMe
OMe
OMe
OMe
P. aeruginosa (−ve). Compounds 5c, 5g, and 5k showed
mediocre activity against the same strain. The structure
activity relationship (SAR) overview of antibacterial
effects of derivatives 5 (Figure 3) indicated that the activ-
ity was influenced by the position of the α-hydroxy-
phosphonate moiety on the aryl ring attached to the
H
H
H
H
a
Isolated yields.
1,2,3-triazole ring through the –OCH -group. In general,
2
the p-position was found to be favorable over the m-
position as except 5g no other compounds having the
α-hydroxyphosphonate group at m-position (e.g., 5f, 5h,
and 5i) showed good activity. The tertiary alcohol at α to
the –PO(OCH ) moiety seemed to have somewhat better
effect than that of secondary alcohol at the same position.
Notably, the presence of a substituent such as OMe on
the benzene ring next to the α-hydroxyphosphonate
group was favorable for activity preferably against the
E. coli. Nevertheless, the activity of compound 5 was also
influenced by the place and nature of substituent, for
example, NO2 or OMe present on the benzene ring
attached to the 1,2,3-triazole ring. Briefly, the analogue
5k seemed to be the most encouraging among these
derivatives examined as it showed activities with MIC of
32, 25, 35, and 36 μg/ml, respectively, against the entire
[
26]. Next, both the reactants, that is, 3 and 4, were
allowed to react in the presence of CuSO .5H O and Na-
ascorbate at room temperature in DMF to furnish the
desired products (5) in moderate to good yields
4
2
3
2
(Scheme 1 and Table 1). A total of 18 new compounds
were prepared and characterized by (NMR, IR, and MS)
1
13
spectral data. Some selected H and C NMR spectral
data of a representative molecule 5o are shown in
Figure 2. Briefly, the two singlets near δ 7.9 and 5.3 in
the H NMR spectra were due to the 1,2,3-triazole ring
proton and the OCH group, respectively. The singlet at δ
1
2
3
.9 was due to the OCH group attached to the aromatic
3
ring, whereas two doublets at δ 3.7 and 3.6 were due to
the diastereotopic OCH groups in PO(OCH ) moiety.
A broad singlet at δ 3.2 and a double doublet at δ 5.0
3
3 2

972
TELU ET AL.
strains, including Gram-positive and Gram-negative bac-
terial species. The analogues 5b, 5c, and 5l though
showed activities against more than one strain, 5l is the
only other compound apart from 5k that showed activi-
ties against both Gram-positive and Gram-negative bacte-
rial strains. Nonetheless, the present class of
α-hydroxyphosphonate-1,2,3-triazole derivatives in gen-
eral appeared to be effective against bacteria and
1
13
FIGURE 2 Selected H (red) and C NMR (blue) signals of
compound 5o [Colour figure can be viewed at
wileyonlinelibrary.com]
FIGURE 3 SAR overview for antibacterial effects of 5 [Colour
figure can be viewed at wileyonlinelibrary.com]
TABLE 2 Antibacterial assessment of 5
a
Zone of inhibition (mm)
Compound
S. aureus (+ve)
E. coli (−ve)
K. pneumoniae (−ve)
P. aeruginosa (−ve)
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
a
b
c
d
e
f
16 ± 0.45
12 ± 0.71
16 ± 0.80
15 ± 0.67
15 ± 0.59
14 ± 0.46
14 ± 0.34
15 ± 0.29
15 ± 0.28
12 ± 0.18
18 ± 0.23
18 ± 0.19
14 ± 0.17
16 ± 0.24
16 ± 0.51
16 ± 0.37
18 ± 0.31
15 ± 0.70
16 ± 0.62
28 ± 0.11
17 ± 0.34
23 ± 0.51
21 ± 0.40
19 ± 0.36
18 ± 0.33
16 ± 0.57
14 ± 0.42
14 ± 0.40
12 ± 0.13
13 ± 0.73
25 ± 0.42
17 ± 0.45
14 ± 0.81
15 ± 0.43
18 ± 0.56
24 ± 0.33
14 ± 0.65
22 ± 0.19
22 ± 0.26
36 ± 0.24
14 ± 0.77
17 ± 0.34
15 ± 0.55
16 ± 0.83
16 ± 0.71
15 ± 0.24
15 ± 0.44
16 ± 0.63
16 ± 0.39
12 ± 0.41
17 ± 0.84
16 ± 0.92
15 ± 0.74
16 ± 0.33
16 ± 0.63
15 ± 0.91
16 ± 0.58
15 ± 0.21
14 ± 0.34
35 ± 0.32
15 ± 0.63
16 ± 0.11
18 ± 0.26
16 ± 0.65
16 ± 0.86
14 ± 0.94
17 ± 0.21
16 ± 0.33
15 ± 0.43
14 ± 0.52
17 ± 0.19
23 ± 0.82
15 ± 0.53
14 ± 0.23
14 ± 0.96
16 ± 0.77
15 ± 0.43
16 ± 0.32
15 ± 0.19
31 ± 0.41
g
h
i
j
k
l
m
n
o
p
q
r
s
pfx
Note: Data are means (n = 3) ± Standard deviation of three replicates.
Abbreviations: E. coli, Escherichia coli; K. pneumonia, Klebsiella pneumoniae; P. aeruginosa, Pseudomonas aeruginosa; pfx, Perfloxacin; S. aureus, Staphylococcus
aureus.
a
Calculation of Zone of inhibition was performed for stock solution at 0.1 mg/50 μl.

TELU ET AL.
973
therefore are of further medicinal interest. Next, some of
the active molecules, for example, 5b, 5c, 5g, 5k, 5l, 5p,
5
q, 5r, and 5s were evaluated for their potential toxicity
by an MTT assay on RAW 264.7 cell line at different con-
centrations. None of them showed significant toxicities
till 30 μM of their concentration tested. Indeed, % cell
viability was found to be 100%, 96%, 89%, 88%, 75%, and
6
1% at the concentration of 1, 3, 10, 30, 60, and 100 μM
of 5k, respectively.
2.3 | In silico studies
The molecular docking studies of compound 5k was per-
formed using Autodock Vina software [30,31] to verify
and understand its interactions with the target protein.
Thus, the binding affinity of 5k toward the DNA-gyrase
cleavage complex of S. aureus and topoisomerase Top. IV
of K. pneumonia organism's DNA binding site encircled
by the protein residues were analyzed in silico separately.
The strong interactions of 5k with the DNA active site
were indicated by the binding affinity of the molecule in
both cases as shown in Table 3.
FIGURE 4 The docking of compound 5k into the active site of
the DNA-gyrase cleavage complex of S. aureus (PDB_ID:5CDQ).
The stick style (in green) shows the molecule and the line style
shows the amino acid residues and DNA bases [Colour figure can
be viewed at wileyonlinelibrary.com]
Initially, the crystal structure of the DNA-gyrase
cleavage complex of S. aureus (PDB_ID: 5CDQ) was
taken into consideration to dock the analogue 5k. The
crystal structure contains an inhibitor Moxifloxacin inter-
calation in the E and F chains of DNA. Some of the
amino acid residues of A and C chains of the DNA-gyrase
complex stabilized the Moxifloxacin bound DNA struc-
ture. The docking of 5k was done in the intercalation
location of DNA of the DNA-gyrase complex. The DNA
bound molecule was stabilized by the H-bonds and
hydrophobic as well as π–π interactions. The stabilization
of m-nitro phenyl ring was aided by the thymine ring
docked in the intercalation location of DNA of the topo-
isomerase, Top. IV complex. The stabilization of DNA
bound molecule was caused by the H-bonds, hydrophobic,
and π–π interactions, whereas the stabilization of the nitro
phenyl ring was aided by the thymine ring (DT-15) of E
chain via π–π interactions. The oxygen of nitro group inter-
acted with the Mg ion. The hydroxyl group of the 5k
formed H-bond with the nitrogen of the adenine ring (DA-
2) of the I chain. These interactions are shown in Figure 5.
2+
3 | CONCLUSIONS
(
DT-8) of the F chain via π–π interactions. The oxygen of
nitro group formed an H-bond with the Ser-84 and also
participated in the interaction with Mg
To conclude, we have presented the preparation, charac-
terization, and in vitro antibacterial screening of a library
of novel compounds based on 1,2,3-triazolo phosphonate
framework along with the evaluation of DNA gyrase
inhibitory potential of a promising molecule in silico.
These compounds were accessed through a multistep
sequence using the Cu(I)-catalyzed azide–alkyne cycload-
dition (CuAAC) as the main reaction step. The Abramov
reaction was used to introduce the phosphonate group
into one of the key reactants. Various α-hydroxyphosph-
onate derivatives containing either a secondary or tertiary
alcohol at the α position were prepared. The characteriza-
2+
ion. These
interactions are shown in Figure 4. In order to consoli-
date these findings, the crystal structure of K. Pneumonia
topoisomerase, Top. IV (PDB_ID: 5EIX) was also taken
into consideration to dock 5k. In this case, the crystal
structure contains the inhibitor Levofloxacin intercala-
tion in the E, F, and I chains of DNA, and some of the
amino acid residues of A and G chains stabilized the
Levofloxacin bound DNA structure. The molecule 5k was
TABLE 3 Binding affinity of compound 5k
1
13
Binding affinity
tion of the products was carried out using IR, H, C,
31
PDB_ID
(kcal/mol)
and P NMR and mass spectrometry. These compounds
were then tested for their antibacterial effects using a
Gram-positive (S. aureus) and three Gram-negative
5
5
CDQ
EIX
−8.1
−8.3
(E. coli, K. pneumoniae and P. aeruginosa) strains via an

974
TELU ET AL.
capillary method). The IR spectra were recorded using a
Bruker-Tensor 27 spectrometer in the form of KBr pellets.
1
13
The H and C NMR spectra were obtained using a
Bruker ACF-300 machine or a Varian 300 or 400 MHz
spectrometer, and the solvent CDCl or DMSO-d was
3
6
used with tetramethylsilane as an internal reference. The
31
P NMR spectra were obtained using a Bruker-AVANCE-
III 400 MHz spectrometer, and DMSO-d was used as a
6
solvent. The mass spectra were obtained using a Jeol JMC
D-300 instrument (electron ionization at 70 eV). Elemental
analyses were performed using Varian 3LV analyzer series
CHN analyzer. TLC (thin layer chromatography) on pre-
coated silica gel plates were used to monitor the progress
of reactions. Column chromatography was carried out by
using silica gel (100–200 mesh, SRL, India) [10–20 times
(
by weight) of the crude compound.
4.2 | Synthesis of alkyne 3
FIGURE 5 The docking of compound 5k into the active site of
the topoisomerase top. IV of K. pneumonia (PDB_ID: 5EIX). The
molecule is shown in stick style (in green) and the amino acid
residues and DNA bases are shown in line style [Colour figure can
be viewed at wileyonlinelibrary.com]
Step 1. To a mixture of aldehyde or ketone (1,
8.1 mmol) and potassium carbonate (2.2 g, 16.2 mmol)
in acetone (15 ml) was added propargyl bromide (1.9
g, 16.2 mmol) dropwise. The stirring of the mixture
was carried out at the refluxing temperature for 3–4 h
and TLC was used to monitor the progress of the reac-
tion. Once the reaction was completed, the mixture
was added to the crushed ice (30 g). The solid precipi-
tated was filtered, collected, and dried under vacuum.
The crude compound (2) isolated was used for the
subsequent step.
agar-well diffusion technique. While majority of the
derivatives were found to be active (with reasonable to good
antibacterial effects), the analogue 5k, that is, dimethyl
(
1-hydroxy-1-(4-((1-(3-nitrophenyl)-1H-1,2,3-triazol-4-yl)
methoxy)phenyl)ethyl) phosphonate exhibited good
effects against the entire strains. The SAR analysis indi-
cated that the activity was influenced by the position of
the α-hydroxyphosphonate moiety as well as the substitu-
ent present on the benzene ring attached to the
When solid was not precipitated out after pouring the
reaction mixture into the crushed ice, the mixture was
treated with ethyl acetate (3 × 15 ml). The organic parts
were collected, combined, washed with NaCl solution
(2 × 15 ml), dried using Na SO (anhyd.), and filtered.
1
,2,3-triazole ring. To assess its potential mechanism of
action (MOA), the interaction of compound 5k with
DNA gyrase was examined in silico when the molecule
showed strong interactions with the DNA active site as
indicated by its binding affinities. Thus, the current study
not only discloses the 1,2,3-triazolo phosphonate frame-
work as a new and promising template for the identifica-
tion of potential antibacterial agents but also
demonstrates the utility of the Abramov reaction
followed by the CuAAC for the synthesis of compounds
based on this framework.
2
4
The filtrate was evaporated under low vacuum and the
residue was dried under vacuum. The crude product (2)
obtained was used for the subsequent step.
Step 2. A suspension of the crude product 2
(0.106 g, 1.0 mmol), anhydrous magnesium chloride
(0.1 g, 1.0 mmol), triethylamine (0.3 g, 3.0 mmol), and
dimethylphosphite (0.136 g, 1.1 mmol) were taken in a
mortar. The mixture was ground for 10 min until a
paste is obtained (TLC was used to monitor the reac-
tion progress). Once the reaction was completed, the
paste was treated with EtOAc (3 × 5 ml). The organic
parts were collected, combined, dried using anhydrous
Na SO , filtered, and evaporated under low vacuum.
4
4
| EXPERIMENTAL
.1 | Chemistry
2
4
The purification of crude compound was carried out
using column chromatography on silica gel and petro-
leum ether/EtOAc as eluent to furnish the expected
compound (3).
Determination of melting points was carried out using a
Bio-technics melting point instrument (open glass

TELU ET AL.
975
1
4
.3 | Spectral data of compound 3
2355.6, 1606.4, 1539.6, 1510.1, 1140.2; H NMR (CDCl ,
3
4
00 MHz): δ 7.18–7.16 (m, 1H), 7.02–6.98 (m, 2H), 5.00
(d, 1H), 4.89 (s, 2H), 3.99 (s, 3H), 3.88 (d, 3H,
J = 12.3 Hz), 3.65 (d, 3H, J = 12.3 Hz), 2.90 (bs, 1H), 2.50
s, 1H); C NMR (CDCl3, 100 MHz): δ 159.8, 149.3,
144.4, 130.3, 122.1, 114.7, 79.9, 76.0, 70.9, 69.3, 62.8, 55.9,
53.7; P NMR (DMSO-d , 400 MHz): δ 23.6.
4
1
.3.1 | Dimethyl (hydroxy(4-(prop-2-yn-
-yloxy)phenyl)methyl)phosphonate (3a)
13
(
ꢀ
White solid; Yield 90%; mp 85-86 C; Rf: 0.56(3:1 Petroleum
ether: Ethyl acetate); MS m/z 271.0 (M + 1, 100%); FTIR
31
6
−1
(KBr,
υ
in cm ): 3260.4, 3049.9, 2945.6, 2913.1,
1
2
4
1
3
1
1
350.11606.4, 1539.6, 1510.1, 1135.2; H NMR (CDCl3,
00 MHz): δ 7.45 (d, 2H, J = 10.0 Hz), 6.91 (d, 2H, J =
0.0 Hz), 5.50 (d, 1H, J = 12.3 Hz), 4.69 (d, 2H, J = 4.0 Hz),
.71 (d, 3H, J = 12.3 Hz), 3.65 (d, 3H, J = 12.3 Hz), 3.62 (bs,
H), 2.50 (t, 1H, J = 4.0 Hz); C NMR (CDCl , 100 MHz):δ
56.5, 131.0, 128.5, 114.1, 79.2, 78.1, 69.5, 67.9, 62.0, 55.3;
4.4 | General procedure for the
preparation of compound 5
13
A mixture of azide 4 (0.53 mmol), an appropriate termi-
3
31
P
nal alkyne
3
(0.53 mmol), CuSO •5H O (65 mg,
4
2
NMR (DMSO-d , 400 MHz): δ 23.6.
0.26 mmol), and sodium ascorbate (52 mg, 0.26 mmol) in
DMF (5 ml) was stirred vigorously for 5 min, at room tem-
perature. The progress of the reaction was monitored by
TLC. After completion of the reaction, the mixture was
poured into the crushed ice (30 g). The solid separated was
filtered, dried, and purified by column chromatography on
silica gel using petroleum ether/ethyl acetate as eluent.
6
4
1
.3.2 | Dimethyl(hydroxy(3-(prop-2-yn-
-yloxy)phenyl)methyl)phosphonate (3b)
Brown Liquid; Yield 90%; Rf: 0.53(3:1 Petroleum ether:
Ethyl acetate); MS m/z 271.0 (M + 1, 100%); FTIR (KBr,
υ in cm ): 3267.4, 3050.9, 2957.6, 2913.1, 2350.1, 1606.4,
−1
1
1
539.6, 1510.1, 1140.2; H NMR (CDCl , 400 MHz): δ
3
7
.51 (d, 1H, J = 8.0 Hz), 7.35–7.30 (m, 1H), 7.09 (t, 1H,
4.5 | Spectral data of compound 5
J = 10.0 Hz), 7.00 (d, 1H, J = 8.0 Hz), 5.50 (d, 1H,
J = 12.3 Hz), 4.53 (s, 2H), 3.89 (d, 3H, J = 12.3 Hz), 3.64
13
4.5.1 | Dimethy(hydroxy
4-((1-(2-nitrophenyl)-1H-1,2,3-triazol-4-yl)
methoxy)phenyl)methyl) phosphonate (5a)
(d, 3H, J = 12.3 Hz), 3.20 (bs, 1H), 2.50 (s, 1H); C NMR
(
(
1
4
CDCl3, 100 MHz): δ 158.2, 143.2, 130.2, 121.2, 114.7,
12.2, 70.8, 69.2, 62.0, 55.9, 53.8; P NMR (DMSO-d6,
00 MHz): δ 23.3.
31
4
2
.3.3 | Dimethyl (1-hydroxy-1-(4-(prop-
-yn-1-yloxy)phenyl)ethyl)
phosphonate (3c)
ꢀ
White solid; Yield 90%; mp 74-76 C; Rf: 0.70(3:1 Petro-
leum ether: Ethyl acetate); MS m/z 285.0 (M + 1, 100%);
−
1
FTIR (KBr, υ in cm ): 3235.4, 3047.9, 2956.6, 2912.1,
1
ꢀ
2
4
4
3
1
1
2
349.1, 1606.4, 1539.6, 1510.1, 1140.2; H NMR (CDCl ,
White solid; Yield 90%; mp 164–166 C; Rf: 0.59 (3:2
3
00 MHz): δ 7.99 (d, 2H, J = 8.0 Hz), 6.80–6.78 (m, 2H),
.80 (d, 2H, J = 4 Hz), 3.99 (d, 3H, J = 12.3 Hz), 3.60 (d,
H, J = 12.3 Hz), 2.89 (bs, 1H), 2.50 (t, 1H, J = 4.0 Hz),
Petroleum ether: Ethyl acetate); MS m/z 435.0 (M + 1,
100%); FTIR (KBr, υ in cm ): 3247.4, 3047.9, 2956.6,
2912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2. H
NMR (CDCl , 400 MHz): δ 8.11 (d, 1H, J = 9.7 Hz), 7.94
(s, 1H), 7.81 (t, 1H, J = 7.7 Hz), 7.73 (t, 1H, J = 8.0 Hz)
7.65 (d, 1H, J = 8.0 Hz), 7.55 (dd, 2H, J = 9.0 Hz, 2.5 Hz),
−1
1
13
.89 (d, 3H, J = 12.3 Hz); C NMR (CDCl 100 MHz): δ
3,
3
56.5, 131.0, 128.5, 114.1, 79.2, 78.1, 69.5, 67.9, 67.0, 62.0,
31
3.8; P NMR (DMSO-d , 400 MHz): δ 26.1.
6
7.03 (d, 2H, J = 9.2 Hz), 5.39 (s, 2H), 5.00 (dd, 1H,
4
4
.3.4 | Dimethyl(hydroxy(3-methoxy-
-(prop-2-yn-1-yloxy)phenyl)methyl)
J = 12.5, 5.0 Hz), 3.75 (d, 3H, J = 10.4 Hz,), 3.67 (d, 3H,
13
J = 10.2 Hz), 3.21 (bs,1H); C NMR (CDCl 100 MHz): δ
3,
phosphonate (3d)
143.6, 132.8, 129.9, 129.1128.0, 127.6, 127.5, 127.0, 124.6,
31
1
23.4, 113.8, 69.9, 68.3, 60.8, 52.8; P NMR (DMSO-d6,
ꢀ
White solid; Yield 90%; mp 71-72 C; Rf: 0.45(3:1 Petro-
leum ether: Ethyl acetate); MS m/z 301.0 (M + 1, 100%);
FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6, 2912.1,
400 MHz): δ 24.1. Elemental Analysis found C, 49.59; H,
4.32; N, 12.68; Calc. for C H N O P; C, 49.77; H,
18
19 4 7
−
1
4.41; N, 12.90.

976
TELU ET AL.
5.30 (s, 2H), 5.00 (dd, 1H, J = 8.0 Hz, 4.0 Hz), 3.90 (s,
4
.5.2 | Dimethy(hydroxy
3H), 3.73 (d, 3H, J = 8.0 Hz), 3.67 (d, 3H, J = 8.0 Hz),
3.14 (dd, 1H, J = 12.0 Hz, 4.0 Hz). C NMR (CDCl3,
13
(
4-((1-(3-nitrophenyl)-1H-1,2,3-triazol-4-yl)
methoxy)phenyl)methyl) phosphonate (5b)
100 MHz): δ 158.2, 151.0, 143.2, 130.2, 129.2, 128.5, 126.1,
1
5
25.4, 125.1, 121.2, 114.7, 112.2, 70.8, 69.2, 61.9, 55.9,
31
3.8; P NMR (DMSO-d , 400 MHz): δ 24.1. Elemental
6
Analysis found C, 54.63; H, 5.28; N, 9.87; Calc. for
C H N O P; C, 54.42; H, 5.29; N, 10.02.
19
22 3 6
4
.5.4 | Dimethyl(hydroxy
4-((1-(3-methoxyphenyl)-1H-1,2,3-triazol-
-yl)methoxy)phenyl) methyl)
phosphonate (5d)
(
4
ꢀ
White solid; Yield 80%; mp 166–168 C; Rf: 0.59(3:2
Petroleum ether: Ethyl acetate); MS m/z 435.0 (M + 1,
−
1
1
2
00%); FTIR (KBr, υ in cm ): 3287.4, 3047.9, 2956.6,
1
912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H
NMR (CDCl , 400 MHz): δ 8.62 (s, 1H), 8.33 (d, 1H,
3
J = 8.0 Hz), 8.22–8.19 (m, 2H), 7.77 (t, 1H, J = 9.5 Hz),
7
.56 (d, 1H, J = 9.5 Hz), 7.45 (d, 1H, J = 10.0 Hz), 7.04 (d,
2
H, J = 10.0 Hz), 5.33 (s, 2H), 5.00 (dd, 1H,
J = 12.3,4 Hz), 3.75 (d, 3H, J = 12.3 Hz), 3.69 (d, 3H,
J = 12.3 Hz), 3.62 (d, 1H, J = 12.3 Hz); C NMR (CDCl3,
13
ꢀ
Light brown solid; Yield 85%; mp 120–122 C; Rf: 0.44
(3:2 Petroleum ether: Ethyl acetate); MS m/z 420.0 (M
1
1
00 MHz): δ 158.1, 144.4, 137.6, 131.0, 128.6, 127.3, 126.0,
31
−1
23.3, 120.7, 115.3, 114.8, 114.3, 71.0, 69.4, 61.8, 53.9;
P
+ 1, 100%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6,
2912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H
1
NMR (DMSO-d , 400 MHz): δ 24.1. Elemental Analysis
6
found C, 49.50; H, 4.43; N, 12.99; Calc. for C H N O P; C,
NMR (CDCl , 400 MHz): δ 8.05 (s, 1H), 7.44 (d, 3H,
18
19
4
7
3
49.77; H, 4.41; N, 12.90.
J = 12.0 Hz), 7.35 (s, 1H), 7.04 (d, 2H, J = 8.0 Hz), 6.98
(
3
d, 2H, J = 8.0 Hz), 5.29 (s, 2H), 5.01 (d, 1H, J = 10.2 Hz),
.89 (s, 3H), 3.73 (d, 3H, J = 11.0 Hz), 3.68 (d, 3H,
13
4
(
4
.5.3 | Dimethyl(hydroxy
4-((1-(2-methoxyphenyl)-1H-1,2,3-triazol-
-yl)methoxy)phenyl) methyl)
phosphonate (5c)
J = 11.0 Hz), 3.30 (bs, 1H); C NMR (CDCl 100 MHz):
3,
δ 160.6, 158.2, 137.9, 130.5, 129.2, 128.6, 128.5, 121.1,
114.7, 112.4, 106.4, 70.9, 69.3, 61.9, 55.6, 53.8. P NMR
31
(DMSO-d6, 400 MHz): 24.1. Elemental Analysis
δ
found C, 54.21; H, 5.28; N, 10.17; Calc. for
C H N O P; C, 54.42; H, 5.29; N, 10.02.
19
22 3 6
4
.5.5 | Dimethyl(hydroxy
4-((1-(4-methoxyphenyl)-1H-1,2,3-triazol-
-yl)methoxy)phenyl) methyl)
phosphonate (5e)
(
4
ꢀ
Light brown solid; Yield 81%; mp 118–120 C; Rf: 0.48
3:2 Petroleum ether: Ethyl acetate); MS m/z 420.0 (M
(
−
1
+
1, 100%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6,
1
2
912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H
NMR (CDCl , 400 MHz): δ 8.19 (s, 1H), 7.79 (dd, 1H,
3
J = 8.0 Hz, 1.7 Hz), 7.46–7.42 (m, 3H), 7.13–7.04 (m, 4H),

TELU ET AL.
977
ꢀ
White solid; Yield 90%; mp 150–152 C; Rf: 0.60 (3:2
Petroleum ether: Ethyl acetate) MS m/z 420.0 (M + 1,
NMR (CDCl , 400 MHz): δ 8.15 (s, 1H), 7.41 (t, 1H,
3
J = 8.2 Hz), 7.37 (t, 1H, J = 2.5 Hz), 7.32–7.28 (m, 2H), 7.23
(m, 1H) 7.08 (d, 1H, J = 12.5 Hz), 6.98–6.96 (m, 2H), 5.30
(s, 2H), 5.06 (d, 1H, J = 11.5 Hz), 3.73 (d, 3H, J = 10.5 Hz),
−1
1
1
00%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6, 2912.1,
606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H NMR
CDCl , 400 MHz):δ 7.98 (s, 1H), 7.63 (d, 2H, J = 9.0 Hz),
.44 (d, 2H, J = 9.0 Hz), 7.02 (d, 4H, J = 9.5 Hz), 5.27 (s,
H), 5.01 (dd, 1H, J = 12.0 Hz, 8.0 Hz), 3.87 (s, 3H), 3.84 (d,
H, J = 8.0 Hz) 3.73 (d, 3H, J = 12.0 Hz), 3.67 (d, 3H,
1
13
(
3.65 (d, 3H, J = 10.5 Hz), 1.76 (bs, 1H, OH); C NMR
(CDCl 100 MHz): δ 158.1, 157.5, 144.4, 137.6, 131.0, 128.6,
3
7
2
3,
127.3, 126.0, 123.3, 120.7, 115.3, 114.8, 114.3, 71.0, 69.4, 61.8,
31
1
54.0, 53.7; P NMR (DMSO-d , 400 MHz): δ 23.8. Elemen-
6
13
J = 12.0 Hz); C NMR (CDCl 100 MHz): δ 159.8, 158.1,
tal Analysis found C, 49.89; H, 4.42; N, 12.73; Calc. for
3,
1
44.4, 130.3, 129.4, 128.6, 128.5, 122.2, 121.2, 114.7, 70.7,
C H N O P; C, 49.77; H, 4.41; N, 12.90.
1
8 19 4 7
31
69.1, 61.8, 55.6, 53.7. P NMR (DMSO-d , 400 MHz): δ 24.1.
6
Elemental Analysis found C, 54.66; H, 5.30; N, 9.86; Calc.
for C H N O P; C, 54.42; H, 5.29; N, 10.02.
4.5.8 | Dimethyl(hydroxy
3-((1-(3-methoxyphenyl)-1H-1,2,3-triazol-
1
9 22 3 6
(
4
.5.6 | Dimethyl(hydroxy
4-yl) methoxy) phenyl) methyl)
phosphonate (5h)
(
3-((1-(2-nitrophenyl)-1H-1,2,3-triazol-4-yl)
methoxy)phenyl)methyl) phosphonate (5f)
ꢀ
Brown solid; Yield 78%; mp 116–118 C; Rf: 0.44 (3:2
Petroleum ether: Ethyl acetate); MS m/z 420.0 (M + 1,
−
1
1
2
00%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6,
Brown liquid; Yield 85%; Rf: 0.48 (3:2 Petroleum ether:
Ethyl acetate); MS m/z 435.0 (M + 1, 100%); FTIR (KBr, υ in
1
912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H
NMR (CDCl , 400 MHz): δ 8.09 (d, 1H J = 8.0 Hz), 7.96
(s, 1H), 7.80 (t, 1H, J = 8.5 Hz), 7.71(t, 1H, J = 7.2 Hz),
−1
3
cm ): 3262.4, 3047.9, 2956.6, 2912.1, 1606.4, 1539.6, 1510.1,
1
1
463.8, 1424.3, 1140.2; H NMR (CDCl , 400 MHz): δ 8.15
3
7
(
3
.63 (d, 1H), 7.05 (m, 2H), 6.89 (d, 1H, J = 8.7 Hz), 6.82
t, 1H, J = 7.0 Hz), 5.37 (s, 2H), 5.27 (d, 1H, J = 11.3 Hz),
.82 (s, 3H), 3.76 (d, 3H, J = 11.0 Hz), 3.69 (d, 3H,
(s,1H), 7.41 (t, 1H, J = 8.2 Hz), 7.37 (t, 1H, J = 2.5 Hz),
7
6
.32–7.28 (m, 2H), 7.23 (m, 1H) 7.08 (d, 1H, J = 12.5 Hz),
.98–6.96 (m, 2H), 5.30 (s, 2H), 5.06 (d, 1H, J = 11.5 Hz), 3.73
1
3
J = 11.0 Hz), 3.55 (bs, 1H); C NMR (CDCl 100 MHz):
3,
(
d, 3H, J = 10.5 Hz), 3.65 (d, 3H, J = 10.5 Hz), 1.76 (1H, OH);
1
3
δ 160.5, 158.1, 144.5, 138.3, 137.9130.5, 129.5, 121.4,
20.1, 115.0, 114.7, 113.1, 112.3, 106.1, 71.1, 69.5, 61.6,
55.6, 53.8; P NMR (DMSO-d , 400 MHz): δ 23.8. Ele-
mental Analysis found C, 54.23; H, 5.27; N, 9.87; Calc. for
C H N O P; C, 54.42; H, 5.29; N, 10.02.
C NMR (CDCl 100 MHz): δ 143.6, 132.8, 129.9, 129.1,
3,
1
1
28.0, 127.6, 127.5, 127.0, 124.6, 123.4, 113.9, 113.8, 69.8, 68.3,
31
31
6
60.8, 52.8; P NMR (DMSO-d , 400 MHz): δ 24.1. Elemental
6
Analysis found C, 49.60; H, 4.43; N, 12.73; Calc. for
19
22 3 6
C H N O P; C, 49.77; H, 4.41; N, 12.90.
18 19 4 7
4
.5.7 | Dimethyl(hydroxy
4.5.9 | Dimethyl(hydroxy
(3-((1-(4-methoxyphenyl)-1H-1,2,3-triazol-
4-ylyl)methoxy)phenyl) methyl)
phosphonate (5i)
(
3-((1-(3-nitrophenyl)-1H-1,2,3-triazol-4-yl)
methoxy)phenyl)methyl) phosphonate (5g)
ꢀ
Brown solid; Yield 80%; mp 120–122 C; Rf: 0.62 (3:2
ꢀ
Petroleum ether: Ethyl acetate) MS m/z 435.0 (M + 1,
1
2
Brown solid; Yield 81%; mp 110–112 C; Rf: 0.60 (3:2
−
1
00%); FTIR (KBr, υ in cm ): 3290.4, 3076.9, 2955.6,
Petroleum ether: Ethyl acetate); MS m/z 420.0 (M + 1,
100%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6,
1
−1
931.2, 1601.4, 1499.4, 1449.4, 1378.6, 1350.3, 1162.7; H

978
TELU ET AL.
1
ꢀ
2
912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H
Brown solid; Yield 78%; mp 150–152 C; Rf: 0.48 (3:2
Petroleum ether: Ethyl acetate); MS m/z 449.0 (M + 1,
NMR (CDCl , 400 MHz): δ 8.05 (s, 1H), 7.65 (d, 2H,
J = 9.2 Hz), 7.30 (t, 1H, J = 8.2 Hz), 7.22 (s, 1H), 7.09 (d,
H, J = 8.7 Hz), 7.03–6.91 (m, 3H), 5.30 (s, 2H), 5.05 (d,
H, J = 12.5 Hz), 3.87 (s, 3H), 3.73 (d, 3H, J = 10.2 Hz),
.67 (d, 3H, J = 10.2 Hz), 3.56 (bs,1H); C NMR (CDCl3,
00 MHz): δ 159.8, 158.1, 144.4, 130.3, 129.4, 128.6, 128.5,
22.2, 121.2, 114.7, 70.7, 69.1, 61.8, 55.6, 53.7; P NMR
DMSO-d , 400 MHz): δ 24.1. Elemental Analysis found C,
4.23; H, 5.27; N, 10.18; Calc, for C H N O P; C,
3
−1
100%); FTIR (KBr, υ in cm ): 3252.4, 3085.0, 3018.5,
2957.1, 1599.4, 1564.6, 1514.1, 1454.3, 1416.2, 1144.7; H
NMR (CDCl , 400 MHz): δ8.62 (s, 1H), 8.32 (d, 1H,
1
1
1
3
1
1
3
13
J = 8.5 Hz), 8.22–8.19 (m, 2H), 7.77 (t, 1H, J = 8.2 Hz), 7.56
(d, 2H, J = 9.2 Hz), 7.02 (d, 2H, J = 9.5 Hz), 5.33 (s, 2H),
3.75 (d, 3H, J = 10.2 Hz), 3.64 (d, 3H, J = 10.2 Hz), 3.52 (d,
31
13
(
5
1H, J = 7.0 Hz), 1.81(d, 3H, J = 15.8 Hz); C NMR (CDCl3,
100 MHz): δ 157.4, 148.9, 145.7, 137.6, 133.8, 131.0, 127.3,
125.9, 123.3, 120.9, 115.3, 114.2, 77.4, 76.7, 74.1, 72.6, 61.8,
6
19 22 3 6
5
4.42; H, 5.29; N, 10.02.
31
5
4.0, 25.8; P NMR (DMSO-d , 400 MHz): δ 26.2. Elemen-
6
tal Analysis found C, 50.69; H, 4.70; N, 12.71; Calc. for
C H N O P; C, 50.90; H, 4.72; N, 12.50.
4
1
4
.5.10 | Dimethyl(1-hydroxy-
-(4-((1-(2-nitrophenyl)-1H-1,2,3-triazol-
-yl) methoxy) phenyl) ethyl)
1
9 21 4 7
phosphonate (5j)
4.5.12 | Dimethyl(1-hydroxy-
1-(4-((1-(2-methoxyphenyl)-1H-1,2,3-triazol-
4-yl)methoxy)phenyl)ethyl)
phosphonate (5l)
ꢀ
White solid; Yield 80%; mp 166–168 C; Rf: 0.46 (3:2
Petroleum ether: Ethyl acetate); MS m/z 449.0 (M + 1,
ꢀ
White solid; Yield 80%; mp 150–152 C; Rf: 0.71 (3:2
Petroleum ether: Ethyl acetate); MS m/z 434.0 (M + 1,
00%); FTIR (KBr, υ in cm ): 3270.7, 3081.7, 2981.7,
954.5, 1610.2, 1588.1, 1534.4, 1467.3, 1414.4, 1175.2; H
NMR (CDCl , 400 MHz): δ 8.19(s,1H), 7.79 (dd, 1H,
−
1
1
2
00%); FTIR (KBr, υ in cm ): 3270.7, 3081.7, 2981.7,
954.5, 1610.2, 1588.1, 1534.4, 1467.3, 1414.4, 1175.2; H
NMR (CDCl ,400 MHz): δ 8.11 (d, 1H, J = 9.7 Hz), 7.94
s, 1H), 7.81 (t, 1H, J = 7.7 Hz), 7.73 (t, 1H, J = 8.0 Hz),
.65 (d, 1H, J = 8.0 Hz), 7.55 (dd, 2H, J = 9.0 Hz, 2.5 Hz),
.03 (d, 2H, J = 9.2 Hz), 5.32 (s, 2H), 3.74 (d, 3H,
−1
1
2
1
1
3
3
(
7
7
J = 8.0 Hz, 4.0 Hz), 7.54 (dd, 2H, J = 12.0 Hz, 4.0 Hz),
7
7
.44 (td, 1H, J = 8.0 Hz, 4.0 Hz), 7.10–7.08 (m, 2H),
.06–7.03 (m, 2H), 5.30 (s, 2H), 3.90 (s, 3H), 3.74 (d, 3H,
J = 12.0 Hz), 3.61 (d, 3H, J = 8.0 Hz), 3.08 (bs,1H), 1.81
d,3H, J = 12.0 Hz); C NMR (CDCl 100 MHz): δ 157.7,
51.1, 143.3, 133.5, 130.2, 127.2, 126. 1, 125.4, 125.0,
21.2, 114.4, 112.2, 74.2, 72.6, 62.0, 55.9, 54.1, 25.7;
NMR (DMSO-d , 400 MHz): δ 26.2. Elemental Analysis
found C, 55.23; H, 5.50; N, 9.52; Calc. for C H N O P; C,
J = 10.2 Hz), 3.61 (d, 3H, J = 10.2 Hz), 2.85 (d, 1H,
1
3
J = 7.5 Hz), 1.82 (d, 3H, J = 15.3 Hz); C NMR (CDCl
13
3,
(
1
1
3,
1
1
6
00 MHz): δ 157.5, 148.9, 145.7, 137.6, 133.8, 131.1, 127.3,
25.9, 123.3, 120.9, 115.3, 114.2, 77.4, 76.7, 74.1, 72.6,
1.8, 54.0, 25.8; P NMR (DMSO-d , 400 MHz): δ 26.3;
Elemental Analysis found C, 50.69; H, 4.74; N, 12.69;
Calc. for C H N O P; C, 50.90; H, 4.72; N, 12.50.
31
P
31
6
6
20 24 3 6
19
21 4 7
5
5.43; H, 5.58; N, 9.70.
4
1
4
.5.11 | Dimethyl(1-hydroxy-
-(4-((1-(3-nitrophenyl)-1H-1,2,3-triazol-
-yl)methoxy) phenyl)ethyl)
4.5.13 | Dimethyl(1-hydroxy-
1-(4-((1-(3-methoxyphenyl)-1H-1,2,3-triazol-
4-yl)methoxy)phenyl) ethyl)
phosphonate (5m)
phosphonate (5k)

TELU ET AL.
979
ꢀ
ꢀ
Pale yellow; Yield 80%; mp 160–162 C; Rf: 0.71 (3:2
Petroleum ether: Ethyl acetate); MS m/z 434.0 (M + 1,
Light Yellow solid; Yield 90%; mp 148–150 C; Rf: 0.44
(3:2 Petroleum ether: Ethyl acetate); MS m/z 465.0 (M
−1
−1
1
00%); FTIR (KBr, υ in cm ): 3270.7, 3081.7, 2981.7,
954.5, 1610.2, 1588.1, 1534.4, 1467.3, 1414.4, 1175.2; H
+ 1, 100%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6,
2912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 113.2; H
1
1
2
NMR (CDCl , 400 MHz): δ 8.05 (s, 1H), 7.56 (d, 1H,
NMR (CDCl , 400 MHz): δ 8.10 (d, 1H, J = 8.2 Hz), 7.96
3
3
J = 2.5 Hz), 7.53 (d, 1H, J = 2.5 Hz), 7.42 (t, 1H,
J = 8.2 Hz), 7.35 (t, 1H, J = 2.5 Hz), 7.28–7.25 (m, 2H),
(s, 1H), 7.81 (t,1H, J = 9.2 Hz), 7.71 (t, 1H, J = 8.2 Hz),
7.63 (d, 1H, J = 9.2 Hz), 7.12 (s, 1H), 7.08 (d, 1H,
J = 8.5 Hz), 7.00 (d, 1H, J = 8.0 Hz), 5.39 (s, 2H), 5.00 (dd,
7
3
.03 (d, 1H, J = 9.0 Hz), 7.00–6.97 (m, 1H) 5.30 (s, 2H),
.89 (s, 3H), 3.74 (d, 3H, J = 10.2 Hz), 3.61 (d, 3H,
1H, J = 12.5,5.0 Hz), 3.90 (s, 3H), 3.75 (d, 3H,
13
13
J = 10.2 Hz), 2.88 (bs, 1H), 1.81 (d, 3H, J = 15.3 Hz);
C
J = 10.4 Hz,), 3.67 (d, 3H, J = 10.2 Hz), 3.21 (bs,1H);
C
NMR (CDCl3, 100 MHz): δ 160.6, 157.6, 144.8, 137.9,
NMR (CDCl3, 100 MHz): δ 149.6, 147.4, 144.8, 144.4,
1
7
33.5, 130.5, 127.2, 121.0, 114.7, 114.3, 112.4, 106. 4, 74.2,
133.8, 130.8, 130.1, 127.9, 125.6, 124.6, 119.7, 114.1, 110.7,
31
31
2.6, 62.0, 56.6, 54.0, 25.8; P NMR (DMSO-d , 400 MHz):
71.0, 69.4, 63.0, 55.9, 53.7; P NMR (DMSO-d , 400 MHz):
6
6
δ 26.2. Elemental Analysis found C, 55.22; H, 5.51; N, 9.62;
δ 23.1. Elemental Analysis found C, 48.96; H, 4.50; N,
Calc. for C H N O P; C, 55.43; H, 5.58; N, 9.70.
11.98; Calc. for C H N O P; C, 49.14; H, 4.56; N, 12.07.
19 21 4 8
20
24
3
6
4
.5.16 | Dimethyl(hydroxy(3-methoxy-
4
1
4
.5.14 | Dimethyl(1-hydroxy-
-(4-((1-(2-methoxyphenyl)-1H-1,2,3-triazol-
-yl) methoxy) phenyl) ethyl
4-((1-(3-nitrophenyl)-1H-1,2,3-triazol-4-yl
methoxy) phenyl) methyl)
phosphonate (5p)
phosphonate (5n)
ꢀ
White solid; Yield 90%; mp 116–118 C; Rf: 0.55 (3:2
ꢀ
White solid; Yield 80%; mp 150–152 C; Rf: 0.71 (3:2
Petroleum ether: Ethyl acetate) MS m/z 434.0 (M + 1,
Petroleum ether: Ethyl acetate); MS m/z 465.0 (M + 1,
−1
100%); FTIR (KBr, υ in cm ): 3288.4, 3046.9, 2957.6,
−
1
1
1
2
00%); FTIR (KBr, υ in cm ): 3265.7, 3071.7, 2980.7,
955, 1600.2, 1568.1, 1534.4, 1467.3, 1443.4, 1165.2; H
2912.1, 1606.4, 1529.6, 1515.1, 1470.8, 1424.3, 1140.2; H
1
NMR (CDCl , 400 MHz): δ 8.62 (s,1H), 8.32 (d, 1H,
3
NMR (CDCl , 400 MHz): δ 7.98 (s, 1H), 7.64 (d, 2H,
J = 12.0 Hz), 7.55 (dd, 2H, J = 8.0 Hz, 4.0 Hz), 7.03 (d,
J = 8.2 Hz), 8.24 (s,1H), 8.18 (d, 1H, J = 8.2 Hz), 7.76 (t,
1H, J = 10.0 Hz), 7.12 (s, 1H), 7.06–7.05 (m, 1H), 7.00 (d,
1H, J = 10.5 Hz), 5.39 (s, 2H), 5.00 (dd, 1H, J = 13.3 Hz,
4.2 Hz), 3.91 (s, 3H), 3.75 (d, 3H, J = 10.5 Hz), 3.69 (d,
3
2
3
3
H, J = 8.0 Hz), 7.02 (d, 2H, 8.0 Hz) 5.29 (s, 2H), 3.87 (s,
H), 3.75 (d, 3H, J = 12.0 Hz), 3.62 (d, 3H, J = 12.0 Hz),
13
13
.20 (d,1H, J = 8.0 Hz), 1.82 (d, 3H, J = 12.0 Hz);
C
3H, J = 10.5 Hz), 3.48 (bs,1H); C NMR (CDCl
3
,
NMR (CDCl3, 100 MHz): δ 159.8, 157.6, 144.6, 133.6,
100 MHz): δ 149.5, 148.9, 147.4, 137.6, 131.0, 130.1, 125.9,
1
7
2
30.3, 127.3, 127.2, 122.2, 121.1, 114.7, 114.3, 114.2, 74.1,
123.3, 121.1, 119.7, 119.6, 115.3, 113.7, 110.7, 71.1, 69.5,
31
31
2.6, 61.9, 55.6, 53.9; P NMR (DMSO-d , 400 MHz): δ
62.9, 55.9, 53.5; P NMR (DMSO-d , 400 MHz): δ 24.1.
6
6
6.3. Elemental Analysis found C, 55.21; H, 5.57; N, 9.92;
Elemental Analysis found C, 48.95; H, 4.49; N, 11.99;
Calc. for C H N O P; C, 55.43; H, 5.58; N, 9.70.
Calc. for C H N O P; C, 49.14; H, 4.56; N, 12.07.
19 21 4 8
20
24
3
6
4
4
.5.15 | Dimethyl(hydroxy(3-methoxy-
-((1-(2-nitrophenyl)-1H-1,2,3-triazol-4-yl)
4.5.17 | Dimethyl(hydroxy(3-methoxy-
4-((1-(2-methoxyphenyl)-1H-1,2,3-triazol-
4-yl)methoxy) phenyl) methyl)
phosphonate (5q)
methoxy)phenyl)methyl) (5o)

980
TELU ET AL.
ꢀ
ꢀ
White solid; Yield 90%; mp 146–148 C; Rf: 0.60 (3:2
White solid; Yield 90%; mp 164–166 C; Rf: 0.44 (3:2
Petroleum ether: Ethyl acetate); MS m/z 450.0 (M + 1,
Petroleum ether: Ethyl acetate); MS m/z 450.0 (M + 1,
00%); FTIR (KBr, υ in cm ): 3245.5, 3085.2, 2956.1, 2846.8,
599.0, 1566.0, 1515.5, 1456.2, 1418.6, 1145.2; H NMR
−1
−1
1
1
100%); FTIR (KBr, υ in cm ): 3245.5, 3085.2, 2956.1,
2846.8, 1599.0, 1566.0, 1515.5, 1456.2, 1418.6, 1145.29; H
1
1
(
CDCl , 400 MHz): δ 8.10 (d, 1H, J = 8.2 Hz), 7.96 (s, 1H),
NMR (CDCl , 400 MHz): δ 8.01 (s, 1H), 7.62 (d, 2H,
3
3
7
.81 (t,1H, J = 9.2 Hz), 7.71 (t, 1H, J = 8.2 Hz), 7.63 (d, 1H,
J = 9.2 Hz), 7.11–7.07 (m, 2H), 7.03–6.98 (m, 3H), 5.36 (s,
2H), 4.99 (d, 1H, J = 12.5 Hz), 3.90 (s, 3H), 3.87 (s, 3H),
3.74 (d, 3H, J = 10.5 Hz), 3.67 (d, 3H, J = 10.5 Hz), 3.40
J = 9.2 Hz), 7.12 (s,1H), 7.08 (d, 1H, J = 8.5 Hz), 7.00 (d, 1H,
J = 8.0 Hz), 5.39 (s, 2H), 5.00 (dd, 1H, J = 12.5 Hz,5.0 Hz),
13
3.90 (s, 3H), 3.87 (s, 3H), 3.75 (d, 3H, J = 10.4 Hz), 3.67 (d,
(bs, 1H); C NMR (CDCl3, 100 MHz): δ 159.8, 149.3,
13
3H, J = 10.2 Hz), 3.21 (bs,1H); C NMR (CDCl 100 MHz):
147.4, 144.4, 130.3, 130.1, 122.1, 121.5, 119.7, 114.7, 113.5,
3,
31
δ 151.0, 149.5, 147.6, 143.3, 130.2, 130.0, 126.1, 125.4, 121.1,
110.8, 70.9, 69.3, 62.8, 55.9, 55.6, 53.7; P NMR (DMSO-
d6, 400 MHz): δ 23.8. Elemental Analysis found C,
53.11; H, 5.21; N, 9.22; Calc. for C H N O P; C,
119.7, 119.6, 113.9, 112.2, 110.8, 110.7, 70.9, 69.3, 63.0, 55.9,
31
53.7; P NMR (DMSO-d , 400 MHz): δ 26.2. Elemental
6
20 24 3 7
Analysis found C, 53.68; H, 5.30; N, 9.29; Calc. for
53.26; H, 5.29; N, 9.30.
C H N O P; C, 53.45; H, 5.38; N, 9.35.
20 24 3 7
4.5.18 | Dimethyl(hydroxy(3-methoxy-
4-((1-(3-methoxyphenyl)-1H-1,2,3-triazol-
4-yl)methoxy) phenyl)methyl)
4.6 | Pharmacology
4.6.1 | Materials and conditions
phosphonate (5r)
Four organisms including one Gram-positive, for exam-
ple, Staphylococcus aureus, and three Gram-negative spe-
cies, for example, K. pneumoniae, P. aeruginosa, and
E. coli, were employed for the measurement of anti-
bacterial effects of our newly prepared derivatives. The
bacterial strains were obtained from the Global Hospitals,
Hyderabad, India. Standard microbiological processes
were utilized to examine the purity of all bacterial strains.
To store the bacterial stock culture, the Mueller Hinton
Agar (MHA) slants were utilized for maintaining the
ꢀ
White solid; Yield 90%; mp 104–106 C; Rf: 0.57; (3:2
Petroleum ether: Ethyl acetate); MS m/z 450.0 (M + 1,
−1
100%); FTIR (KBr, υ in cm ): 3262.4, 3047.9, 2956.6,
1
2912.1, 1606.4, 1539.6, 1510.1, 1463.8, 1424.3, 1140.2; H
ꢀ
NMR (CDCl , 400 MHz): δ 8.08 (s, 1H), 7.41 (t, 1H,
temperature at 4 C with a subculture period of 15 days.
3
J = 8.2 Hz), 7.34–7.32 (m, 1H), 7.24(1H, d, J = 4.0 Hz), 7.09
The surface viable counting technique was used for the
maintenance of microbial stock solution with a concen-
tration of 108–109 colony forming units (CFU)/ml. The
preparation of a 24-h old microbial stock suspension was
undertaken each time, and the experimental conditions
(temperature and aeration) were maintained constant
prior to the antimicrobial assay was performed.
(
d, 2H, J = 8.7 Hz), 7.02–6.96 (m, 2H), 5.38 (s,2H), 4.99 (dd,
1H, J = 12.0 Hz, 8.0 Hz), 3.91 (s, 3H), 3.88 (s, 3H,
J = 10.5 Hz), 3.75 (d, 3H, J = 12.0 Hz), 3.67 (d, 3H,
13
J = 12.0 Hz), 2.85 (dd, 1H, J = 8.0 Hz, 12.0 Hz); C NMR
(
CDCl 100 MHz): δ 160.5, 149.5, 149.4, 147.5, 137.9, 130.5,
3,
1
29.9, 121.3, 119.7, 119.6, 114.7, 113.7, 110.7, 106.3, 70.6,
31
69.4, 62.9, 55.9, 55.6, 53.7. P NMR (DMSO-d , 400 MHz):
6
δ 23.8 Elemental Analysis found C, 53.08; H, 5.30; N, 9.47;
Calc. for C H N O P; C, 53.26; H, 5.29; N, 9.30.
4.6.2 | The assay protocol
2
0 24 3 7
4
4
4
.5.19 | Dimethyl(hydroxy(3-methoxy-
-((1-(4-methoxyphenyl)-1H-1,2,3-triazol-
-yl)methoxy) phenyl)methyl)
The Agar well diffusion procedure was employed for
assessing the antimicrobial effects [22,23]. The standard-
ized microbial stock suspension (1 × 108) (100 μl) and
molten Mueller-Hinton Agar medium was mixed thor-
oughly and then poured into the sterile Petri plates.
Three 8 mm wells were made using a sterile cork borer
no 4In in each Petri plate. Then, to two of the wells was
added 50 μl of solution containing 0.5 mg of compound,
whereas 50 μl of solution containing 0.05 mg of “a broad
spectrum” antibiotic Perfloxacin (as the control) was
added to the third well. In order to allow the bacterial
phosphonate (5s)
ꢀ
growth, plates were then incubated overnight at 37 C.

TELU ET AL.
981
After incubation, the measurement of the diameter of the
zones of inhibition was carried out and charted for each
microorganism.
x = 22, y = 32, z = 32. Then, advanced genetic algorithm
method in Vina was used to generate 20 conformations
in each docking output, whereas MGLTools-1.5.6 soft-
ware was used for the protein/DNA complex as well as
molecule input preparations and docking output
analysis.
4.6.3 | Measurement of MIC
To determine the MIC, the microorganism's susceptibility
tests in nutrient and potato dextrose broths were
employed [24]. The stock solutions (1000 μg/ml) of the
tested compounds and perfloxacin in DMSO were pre-
pared followed by dilutions to 250–25 μg/ml concentra-
tions. For MIC determination, the incubation of
ACKNOWLEDGMENT
Jhonsee Rani Telu thanks DST-INSPIRE, New Delhi,
India, for a Junior Research Fellowship. The authors also
thank CFRD, Osmania University, India and JNTU
Hyderabad, India for support.
ꢀ
inoculated microorganism suspensions was done at 37 C
DATA AVAILABILITY STATEMENT
for 1–5 days. Then, the inoculation of microorganism sus-
pensions into the concentrations of corresponding com-
pounds and control experiments was carried out.
The data that supports the findings of this study are avail-
able in the supplementary material of this article.
ORCID
Sarbani Pal https://orcid.org/0000-0003-1730-0782
Jaya Shree Anireddy https://orcid.org/0000-0002-4714-
4.6.4 | MTT assay
2044
Initially, 20,000–25,000 cells per well were seeded in a
6-well plate and incubated with the test compound at
different concentrations for 24 h. After treatment, the
MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
REFERENCES
9
[
[
1] T. E. Ali, S. M. Abdel-Kariem, ARKIVOC 2015, 2015, 246.
2] K. Moonen, I. Laureyn, C. V. Stevens, Chem. Rev. 2004, 104,
6177.
bromide] reagent was added to a final concentration of
[3] R. K. Bansal Ed., Topics in Heterocyclic Chemistry, Vol. 21,
Springer, Berlin, Germany 2010.
ꢀ
0
.25 mg/ml and incubated at 37 C for 2 h. After 2 h, media
was removed completely, and the intracellular purple
formazan crystals were dissolved in 100 μl of DMSO. The
absorbance of this solution was measured at 570 nm. Each
concentration of the compound was performed in tripli-
cate, and the relative cell viability was expressed as a per-
centage relative to the untreated control cells.
[
4] P. Kafarski, B. Lejczak, J. Mol. Catal. B Enzym 2004, 29, 99.
[5] A. H. Kategaonkar, R. U. Pokalwar, S. S. Sonar, V. U. Gawali,
B. B. Shingate, M. S. Shingare, Eur. J. Med. Chem. 2010, 45,
1128.
[6] R. Snoeck, A. Holy, C. Dewolf-Peeters, J. Van Den Ord, E. De
Clercq, G. Andrei, Antimicrob. Agents Chemother. 2002, 46,
3356.
[7] R. U. Pokalwar, R. V. Hangarge, P. V. Maske, M. S. Shingare,
Arkivoc 2006, 2006(11), 196.
4.7 | Molecular docking
[8] R. M. N. Kalla, H. R. Lee, J. Cao, J. W. Yoo, I. Kim, New
J. Chem. 2015, 39, 3916.
Molecular docking studies were carried out using
Autodock Vina software [25,26] (an open-source molecu-
lar docking software). The molecule 5k was docked into
the crystal structures of DNA-gyrase cleavage complex of
S. aureus (Gram-positive bacteria) with PDB_ID:5CDQ,
and the cleavage complex of topoisomerase Top. IV of
K. pneumonia (Gram-negative bacteria) with PDB_ID:5EIX.
A grid box was generated with desired parameters
around the active site of DNA-gyrase cleavage complex of
S. aureus (PDB_ID:5CDQ) as the center: x = 40.123,
y = −46.732, z = 64.933 and grid box size: x = 22, y = 36,
z = 26. Another grid box was generated with desired
parameters around the active site of topoisomerase Top.
IV of K. pneumonia (PDB_ID:5EIX) as the center:
x = 183.18, y = − 28.952, z = −7.879 and grid box size:
[9] A. Tripolszky, E. Tóth, P. T. Szabó, L. Hackler Jr., B. Kari,
L. G. Puskás, E. Bálint, Molecules 2020, 25, 2643. https://doi.
org/10.3390/molecules25112643.
10] K. S. Ju, J. R. Doroghazi, W. W. Metcalf, J. Ind. Microbiol. Bio-
technol. 2014, 41, 345. https://doi.org/10.1007/s10295-013-
[
[
1375-2.
11] K. Lal, P. Yadav, A. Kumar, A. Kumar, A. K. Paul, Bioorg.
Chem. 2018, 77, 236.
[12] A. H. Kategaonkar, P. V. Shinde, A. H. Kategaonkar, S. K.
Pasale, B. B. Shingate, M. S. Shingare, Eur. J. Med. Chem.
2010, 45, 3142.
[
[
[
13] B. Garudachari, A. M. Isloor, M. N. Satyanarayana, H. K. Fun,
G. Hegde, Eur. J. Med. Chem. 2014, 74, 324.
14] K. Naveen, J. R. Telu, V. Banothu, S. B. Nallapati, J. S.
Anireddy, S. Pal, Med. Chem. Commun. 2015, 6, 1612.
15] S. Pal, N. Kuntala, J. R. Telu, V. Banothu, J. S. Anireddy, Der
Pharma Chem 2017, 9, 1.

982
TELU ET AL.
[
16] K. Naveen, J. R. Telu, V. Banothu, S. Balasubramanian, J. S.
Anireddy, S. Pal, Mini Rev. Med. Chem. 2018, 18, 803.
17] L. Freire-Moran, B. Aronsson, C. Manz, I. C. Gyssens, A. D.
So, D. L. Monnet, O. Cars, the ECDC-EMA working group,
Drug Resist. Updates 2011, 14, 118.
[27] F. Kavanagh, Analytical Microbiology, Vol. II, Academic Press,
New York and London 1972, p. 11.
[
[28] S. S. Miles, S. S. Misra, J. O. Irwin, J Hyg 1938, 38, 732.
[29] V. Singh, D. Katiyar, Bioorg. Chem. 2017, 71, 120.
[30] O. Trott, A. Olson, J. Comput. Chem. 2010, 31, 455.
[31] G. M. Morris, R. Huey, W. Lindstrom, M. F. Sanner, R. K.
Belew, D. S. Goodsell, A. J. Olson, J. Comput. Chem 2009, 16,
2785.
[
[
[
[
18] D. J. Payne, M. N. Gwynn, D. J. Holmes, D. L. Pompliano,
Nat. Rev. Drug Discov. 2007, 6, 29.
19] J. D. Bilavendran, A. Manikandan, P. Thangarasu, K.
Sivakumar, J. Heterocycl Chem. 2020, 57, 1143.
20] S. R. Ashok, M. K. Shivananda, M. S. Prakash, S. Sreenivasa,
A. Manikandan, J. Heterocycl Chem. 2020, 57, 1211.
21] A. Manikandan, V. P. Muralidharan, M. Andrew, M. H.
Ahmed, K. I. Sathiyanarayanan, A. Sivakumar, Mol. Inf. 2018,
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of this
article.
3
7, 1800048.
22] A. Manikandan, A. Sivakumar, Bioorg. Med. Chem. 2017, 25,
448.
[
[
[
[
[
1
23] T. Ponnusamy, A. Manikandan, S. Thamaraiselvi, Bioorg. Med.
Chem. 2018, 26, 3438.
24] H. C. Kolb, M. G. Finn, K. B. Sharpless, Angew. Chem., Int. Ed.
How to cite this article: Telu JR, Kuntala N,
Kankanala K, Banothu V, Pal S, Anireddy JS.
Novel 1,2,3-triazolo phosphonate derivatives as
potential antibacterial agents. J Heterocyclic Chem.
2
001, 40, 2004.
25] M. Tajbakhsh, S. Khaksar, Z. Tafazoli, A. Bekhradnia, Chin.
J. Chem. 2012, 30, 827.
26] F. Nemati, A. Elhampour, J. Appl. Chem. 2012, 7, 29.
2021;58:969–982. https://doi.org/10.1002/jhet.4230