Synthesis, herbicidal evaluation, and structure-activity relationship of benzophenone oxime ether derivatives

Article abstract of DOI:10.1155/2015/435219

A novel series of benzophenone oxime ether derivatives with tertiary amine groups were synthesized and their herbicidal activities of 24 compounds against Oryza sativa, Sorghum sudanense, Brassica chinensis, and Amaranthus mangostanus L. were also evaluated. Most of these compounds exhibited significant inhibitory effect on root growth at 20 ppm. Based on the herbicidal activity data, computational Three-Dimensional Quantitative Structure-Activity Relationship (3D-QSAR) analysis and molecular docking were undertaken. CoMFA contour maps were generated for the design of benzophenone oxime ether analogues with enhancing activity.

Full text of DOI:10.1155/2015/435219

Hindawi Publishing Corporation
Journal of Chemistry
Volume 2015, Article ID 435219, 8 pages
http://dx.doi.org/10.1155/2015/435219
Research Article
Synthesis, Herbicidal Evaluation, and Structure-Activity
Relationship of Benzophenone Oxime Ether Derivatives
Jimei Ma, Mingwei Ma, Linhao Sun, Zhen Zeng, and Hong Jiang
Department of Chemistry, College of Sciences, Huazhong Agricultural University, Wuhan 430070, China
Correspondence should be addressed to Hong Jiang; jianghong0066@126.com
Received 30 April 2015; Revised 3 July 2015; Accepted 8 July 2015
Academic Editor: Florent Barbault
Copyright © 2015 Jimei Ma et al. is is an open access article distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
A novel series of benzophenone oxime ether derivatives with tertiary amine groups were synthesized and their herbicidal activities
of 24 compounds against Oryza sativa, Sorghum sudanense, Brassica chinensis, and Amaranthus mangostanus L. were also evaluated.
Most of these compounds exhibited significant inhibitory effect on root growth at 20 ppm. Based on the herbicidal activity data,
computational ree-Dimensional Quantitative Structure-Activity Relationship (3D-QSAR) analysis and molecular docking were
undertaken. CoMFA contour maps were generated for the design of benzophenone oxime ether analogues with enhancing activity.
1. Introduction
excellent antibacterial and antifungal activity [12]. Zhang
et al. demonstrated that 4-methoxybenzaldehyde O-(4-
bromobenzyl) oxime exerted good larvicidal activity against
Myzus persicae and its analogues exhibited excellent fungici-
dal activity against Rhizoctonia solani [13]. Sun et al. reported
that some benzoylphenylureas containing an oxime ether
group showed excellent larvicidal activities against mosquito
and oriental armyworm [6]. Besides, some 2,4-diphenyl-1,3-
oxazolines containing oxime ether moiety exhibited higher
acaricidal activity than etoxazole [2]. A few pyrazole oxime
ether derivatives exhibited both good acaricidal and insecti-
cidal activities [14–16]. More recently, a series of benzofuran-
substituted oxime ethers were identified to possess good to
excellent fungicidal activities by Xie et al. [17, 18].
Pesticides are extensively used in agriculture and undoubt-
edly play a pivotal role in retaining high production and qual-
ity of crop [1]. Nevertheless, with the escalating demand
of environment protection and food safety, the economic,
health, and environmental costs of pesticides have to be
considered [2]. is requires that pesticides must be selective,
effective, of less residue, and safe. On the other hand, most
pesticides could lose efficacy due to resistance afer long-term
usage. us, continuous effort has been made to develop new
pesticides with broad spectrum, low dosage and cost, long
efficacy duration, less environmental pollution, and safety to
humans [3, 4].
In recent years, oxime ether derivatives exhibit high
potential to be developed as pesticides. For example, flucy-
cloxuron is an insect growth regulator and trifloxystrobin
has been used as a fungicide. Moreover, various novel oxime
ethers have been reported to possess remarkable antibac-
terial, insecticidal, and fungicidal activities [5–9]. A series
of O-benzyl oxime ethers containing ꢀ-methoxyacrylate
moiety was synthesized by Liu et al. and was found to
possess both fungicidal and insecticidal activities [5, 10,
11]. Kabilan group revealed that oxime ethers derived from
1-allyl substituted 2,6-diphenylpiperidin-4-ones displayed
However, very few results on the herbicidal activities of
oxime ether compound were reported [19]. In this paper, a
series of aryl oxime ether compounds with tertiary amino
groups which are conducive to enhancing environmental
compatibility [17, 20] were designed and synthesized. e
herbicidal activities of these compounds on Oryza sativa,
Sorghum sudanense, Brassica chinensis, and Amaranthus
mangostanus L. were investigated. Computational ree-
Dimensional Quantitative Structure-Activity Relationship
(3D-QSAR) analysis and molecular docking were also under-
taken.

2
Journal of Chemistry
OH
R1
O
O
N
NH2OH·HCl
AlCl3
Cl
Base
+
R1
R1
1
2
3
Br
Br
Amine
O
O
R2
N
Br
N
R1
R
4
5
R1 = Cl, Br, CH3
R2 = piperidyl, piperazinyl, morpholinyl, and so forth
Scheme 1: e synthetic route to target compounds.
2. Materials and Methods
ethanol (50 mL) at room temperature. en, the reaction was
heated to 75∘C and stirred until the starting material was
completely consumed as indicated by TLC. e mixture was
cooled to room temperature and filtered. e filtrate was
evaporated and dissolved in chloroform, washed with water.
e crude compound was recrystallized by ethanol to give a
white solid [21].
2.1. General. All reagents and solvents (Analytical Reagent
grade) were commercially available and used without further
purification. Melting points were measured on an RY-2
apparatus. IR spectra were recorded on a ermo Nicolet
1
FT-IR Avatar 330 instrument with KBr. H NMR spectra
were collected at room temperature on 400 MHz Bruker AM,
600 MHz Bruker DRX spectrometers. e residual solvent
2.2.3. General Procedure for the Synthesis of Substituted Ben-
zophenone-O-(2-bromoethyl) Oxime. Aqueous NaOH solu-
tion (10 mL, 25 M) was added to a mixture of substi-
tuted benzophenone oxime (0.025 mol), 1,2-dibromoethane
(0.03 mol), and tert-butylammonium bromide (0.2 g) in
toluene (20 mL). e mixture was stirred at room tempera-
ture and monitored by TLC. Afer the reaction was com-
pleted, the resulting solution was separated. e organic
phase was washed with water until neutral, dried over
signals were taken as the reference (7.26 ppm in CDCl and
3
2.50 ppm in ꢁ6-DMSO). Chemical shif (ꢂ) is reported in
ppm; coupling constants (ꢃꢄ are given in Hz. e following
abbreviations classify the multiplicity: s = singlet, d = doublet,
t = triplet, and m = multiplet or unresolved. MS (ESI) spectra
were recorded on Agilent 6100 Single Quad spectrometer.
2.2. Chemical Synthesis. Aryl ketone was prepared from
substituted benzene and arylcarboxylic chloride through
Friedel-Crafs reaction. Reaction of ketone with hydroxy-
lamine hydrochloride in the presence of base would result
in corresponding oxime, which converted to substituted
benzophenone-O-(2-bromoethyl) oxime. Finally, the target
products could be obtained by substitution (Scheme 1).
MgSO , and filtered. e filtrate was evaporated and purified
4
by column chromatography on silica gel to give substituted
benzophenone-O-(2-bromoethyl) oxime [22].
2.2.4. General Procedure for the Synthesis of Target Com-
pounds. A mixture of substituted benzophenone-O-(2-bro-
moethyl) oxime (0.01 mol), amine (0.012 mol), and Na CO
2.2.1. General Procedure for the Synthesis of Substituted Ben-
2
3
zophenones. Benzoyl chloride (0.12 mol) was added dropwise
(0.01 mol) in acetone (20 mL) was stirred at room tempera-
ture. e reaction was monitored by TLC. Afer the reaction
was completed, the resulting suspension was filtered. e
filtrate was evaporated to remove acetone and the residue
was dissolved in EtOAc (20 mL), washed with water, dried
to a mixture of substituted benzene (0.1 mol) and AlCl
3
(0.12 mol) at room temperature. Afer complete addition, the
mixture was refluxed for another 6 h. en, the reaction was
quenched with ice-water and extracted with chloroform (3 ×
30 mL). e combined organic phase was washed with water,
Na CO solution, and brine successively, dried over MgSO ,
over MgSO , filtered, and evaporated. e crude product
4
was purified by column chromatography on silica gel [23].
2
3
4
filtered, and evaporated. e crude product was used directly
for next step without any further purification.
e unreacted substituted benzophenone-O-(2-bromoethyl)
oxime was removed by Et O/petroleum ether = 1 : 10. e
2
final products (Table 1) were obtained by eluting with the
indicated solvent. e characterization of compounds 5a–
5x was included in the Supporting Information in Supple-
mentary Material available online at http://dx.doi.org/10.1155/
2015/435219.
2.2.2. General Procedure for the Synthesis of Substituted
Benzophenone Oximes. Aqueous NaOH solution (10 mL,
20 M) was added to a mixture of substituted benzophenone
(0.05 mol) and hydroxylamine hydrochloride (0.1 mol) in

Journal of Chemistry
3
Table 1: Chemical structure of the target compounds 5a–5x.
Compound
R1
R2
Compound
R1
R2
N
N
5a
p-Cl
−N(CH CH CH )
5m
p-Me
2
2
3
2
Ph
N
N
5b
p-Cl
−N(CH CH CH CH )
5n
p-Cl
2
2
2
3
2
2
N
N
5c
5d
5e
5f
p-Me
p-Me
p-Me
p-Cl
−N(CH CH CH )
5o
5p
5q
5r
5s
5t
p-Me
p-Cl
p-Br
p-Me
p-Cl
p-Br
2
2
3
2
N
O
−N(CH CH CH CH )
2
2
2
3
N
N
O
O
N
N
N
N
CO2H
CO2H
N
5g
5h
p-Br
o-Cl
N
CO2H
N
5i
5j
p-NO
5u
5v
p-Cl
p-Br
p-Cl
p-Br
2
N
CO2H
N
N
N
p-Cl
p-Br
p-Cl
N
HO2C
N
5k
5w
5x
N
HO2C
N
N
5l
N
See Scheme 2.
O
R2
N
R1
5
Scheme 2
2.3. Biological Testing. e in vivo herbicidal activities of
compounds 5a–5x against monocotyledon (Oryza sativa,
Sorghum sudanense) and dicotyledon (Brassica chinensis,
Amaranthus mangostanus L.) were examined according to the
plating method in agricultural industry standard of China
pesticide indoor bioassay test criteria (herbicide) (NY/T
1155.1, 2006).
e weeds were soaked in 25∘C water for 12 h and then
transferred to moist gauze, which was put in manual climatic
box at 28∘C to germinate. 0.12 g of the target compounds

4
Journal of Chemistry
was diluted with 3 mL DMF. 0.5 mL of the diluted solution
was diluted to 100 mL with 0.1% aqueous Tween-80 solution
to prepare a mother solution (200 g/L). e test solutions
were then prepared by diluting suitable mother solution to
100 mL with 0.1% aqueous Tween-80 solution. 10 germinating
seeds were selected and put in the Petri dish matted with a
filtered paper, to which 9 mL of testing solution was added.
0.1% aqueous Tween-80 solution was used as blank control.
e Petri dishes were put in manual climatic box setting
temperature as 25∘C and humidity as 98% in dark condition.
e root length was measured afer 5 days and the inhibitory
rate was calculated with the following equation. All the
samples were repeated for 3 times. e abnormal data was got
rid of by SPSS19.0. Consider
Figure 1: Common skeleton of target compounds.
3. Results and Discussion
3.1. Herbicidal Activity Evaluation. Afer a preliminary study,
the concentration of testing compounds was set as 1, 2.5, 5,
10, 20, and 40 mg/L in the herbicidal activity investigation.
e root growth was observed and the collected data was
analyzed by SPSS to calculate the inhibitory rate. e results
showed that the inhibitory effect became stronger as the
concentration was increased and most of these compounds’
inhibitory rates were up to 80% above at 20 mg/L (see
Supporting Information). It indicated that these oxime ether
compounds with tertiary amines significantly inhibited the
crop root growth, which is another example to support
the point that nitrogen functional groups are significant
ꢇ0 − ꢇ1
ꢅ ꢆ
× 100.
(1)
ꢇ0
ꢅ is growth inhibitory rate (%); ꢇ0 is the root length of
control; ꢇ1 is the root length of testing sample.
A coordinate plot was built with concentration as ꢈ axial
and inhibitory rate as ꢉ axial. Linear fitting was processed
for each compound to give the univariate linear regression
equation (the correlation data was attached in the supporting
for the biological activity in most agrochemicals [29]. IC ,
90
information). IC was calculated by the linear equation.
90
the concentration inhibiting 90% of activity, was calculated
according to the correlation analysis between the inhibitory
rate on root growth and the concentration of the testing solu-
tion (see Supporting Information). Compound 5f exhibited
pIC was the value of log IC .
90
90
2.4. Molecular Modeling. e analysis is based on SYBYL
7.3 (Tripos Inc., USA). A training set of 19 compounds
was used to construct the 3D-QSAR models. Considering
the distribution of the structural diversity, 5 compounds
were randomly selected as prediction test set to evaluate the
obtained 3D-QSAR model.
the best herbicidal activity against Oryza sativa with an IC
90
of 13.70 mg/L. Compound 5o effectively inhibited the root
growth of Sorghum sudanense with an IC of 11.27 mg/L.
90
Compounds 5k and 5i showed the highest herbicidal activity
against Brassica chinensis and Amaranthus mangostanus L.
with an IC of 16.83 and 11.22 mg/L, respectively. e
Since the acceptor is unknown, the low energy con-
formation was chosen as the active conformation [24, 25].
Molecules are minimized by Tripos force field and the Powell
conjugate gradient algorithm with a convergence criterion of
90
herbicidal activities of these compounds are comparable to
those of tribenuron, which is a commonly used commercial
herbicide [30] (Table 2).
It was noteworthy that the benzophenone oxime ethers
containing piperidine or piperazine moiety (5e–5o) showed
significant inhibitory activities. Increase of the concentration
of these kinds of compounds to 20 mg/L caused plants’
fatality. e compounds containing oxygen atom on amino
moiety (5p–5r) show less inhibitory effect than that of
those without oxygen (5a–5o). In particular, incremental
carboxylic acid group on piperidine ring (5s–5x) strongly
reduced the herbicidal activities. e inhibitory effects of the
testing compound on Oryza sativa were generally stronger
than those of Sorghum sudanense in terms of monocotyledon,
while the inhibitory effects on Amaranthus mangostanus L.
were better than those of Brassica chinensis as for dicotyledon.
˚
0.05 kcal/(mol A) to give the low energy conformation, and
then all compounds were aligned by Database Alignment
method. Compound 5k was selected as template molecule
[26]. Other molecules are overlapped to reduce the root-
mean-square derivation. e common skeleton was shown in
Figure 1.
e composite data and pIC data were imported to cal-
90
culate the CoMFA field parameters by Tripos Standard force
field (the steric and electrostatic field). Default parameters
such as dielectric constant were used to obtain the molecular
force parameters [27, 28]. Partial Least-Square (PLS) method-
ology was employed to construct the relationships between
the target compound and biological activity. e leave-one-
out (LOO) cross-validation was performed to obtain the
2
cross-validation correlation coefficient (ꢊ ) and the optimum
3.2. Comparative Molecular Field Analysis (CoMFA). e
CoMFA analysis results for Oryza sativa and Amaranthus
mangostanus L. were listed in Table 3. e activities data
of Sorghum sudanense and Brassica chinensis did not show
satisfactory regularity and CoMFA model was not analyzed.
number of components (ꢋ). A non-cross-validated (NV)
analysis was carried out to obtain the non-cross-validated
2
correlation coefficient (ꢌ ) and ꢍ test values and standard
error of estimate (SEE).

Journal of Chemistry
Compound
5
Table 2: Calculated IC of compounds 5a–5x.
90
IC
90
Oryza sativa
12.28
Sorghum sudanense
13.70
Brassica chinensis
Amaranthus mangostanus L.
Tribenuron
11.89
25.28
43.81
35.72
68.52
33.92
32.73
32.17
11.06
12.71
22.14
17.96
31.56
18.38
34.01
17.32
25.51
11.22
5a
5b
5c
5d
5e
5f
5g
5h
5i
5j
5k
5l
5m
5n
5o
5p
5q
5r
5s
21.11
33.55
26.55
17.81
34.27
60.06
48.10
55.20
21.09
42.04
44.92
14.85
13.70
34.19
52.88
24.79
20.13
18.11
20.55
21.28
36.42
17.23
25.54
20.65
35.74
52.34
28.02
22.84
16.83
17.21
16.83
11.72
15.70
17.69
36.87
21.52
11.27
55.64
52.96
244.24
39.85
387.23
194.54
733.00
121.02
133.36
48.70
87.47
23.67
97.02
146.21
439.01
68.15
134.91
108.17
140.28
130.27
147.23
17.47
19.22
14.67
46.68
50.55
53.68
43.25
139.05
203.32
115.99
216.57
379.80
20.44
56.79
102.32
72.32
107.40
106.86
67.62
90.00
89.43
121.02
5t
5u
5v
5w
5x
Table 3: Summary of CoMFA results.
LOO
NV
Fields
Steric
Electrostatic
2
2
ꢊ
ꢋ
2
3
ꢌ
SEE
0.020
0.185
ꢍ
Oryza sativa
Amaranthus mangostanus L.
0.567
0.621
0.997
0.879
751.322
53.325
0.446
0.481
0.554
0.519
2
e CoMFA model for Oryza sativa has a ꢊ value of
and 5. In both models, most of the predicted pIC values
90
2
are pretty close to the corresponding experimental values. All
the deviations are smaller than 1 log unit and the maximum
deviation is only 0.321.
0.567 and ꢌ value of 0.997. It has an ꢍ value of 751.322 and
an SEE value of 0.020. e CoMFA model for Amaranthus
2
2
mangostanus L. has a ꢊ value of 0.621 and ꢌ value of
0.879. It has an ꢍ value of 53.325 and an SEE value of 0.185.
2
2
2
According to the literature [31], the ꢊ (ꢊ > 0.5) and ꢌ
3.3. Contour Map Analysis. e 3D contour maps were
generated as scalar products of coefficients and standard
deviation associated with each CoMFA. e active compound
5k was superimposed with the CoMFA contour maps for
Oryza sativa and Amaranthus mangostanus L.
In Figure 2, yellow region near benzene ring shows
that substituents at this position have unfavorable steric
interaction. is is verified by the observation that compound
5h with o-Cl on benzene exhibited less inhibition than that of
5f with p-Cl. Blue region below the chain especially around
the amino groups indicates that electronegative groups are
unfavored in this region. is is rightly explained by the
fact that compounds 5s–5x with extra carboxylic acid group
2
(ꢌ > 0.6) values illustrated that the resulted models have
good robustness and internal prediction ability. Both models
revealed that the electrostatic field (55.4%, 51.9%) has a little
bit more contribution than that of steric fields (44.6%, 48.1%).
is indicated that the electronic effect of testing compounds
structure has more influence on the inhibitory activities
against the plants’ roots.
e 3D-QSAR models established with the training set
were further validated with the test set. e CoMFA model
gave reasonable predictions of both training and test set
compounds. e experimental activity and predicted activity
of the compounds and their residuals are listed in Tables 4

6
Journal of Chemistry
Table 4: Observed and predicted activities for training and test set
of Oryza sativa CoMFA model.
Table 5: Observed and predicted activities for training and test set
of Amaranthus mangostanus L. CoMFA model.
pIC
Predicted
1.345
1.311
1.600
1.591
1.207
pIC
Predicted
1.414
1.307
1.110
1.456
1.268
90
90
Compound
Compound
Observed
1.32
Residual
−0.025
0.009
Observed
1.10
Residual
−0.314
0.043
5a
5a
5b
5c
1.32
1.62
1.65
1.17
5b
5c
1.35
1.25
1.50
1.26
0.020
0.059
−0.037
0.140
5d∗
5d∗
0.044
5e
5e
−0.008
5f
1.14
1.53
1.72
1.39
1.30
1.26
1.31
1.33
1.24
1.31
1.75
2.01
1.86
2.03
2.03
1.83
1.95
1.95
2.08
1.158
1.558
1.716
1.361
1.326
1.248
1.274
1.352
1.259
1.511
1.746
1.992
2.156
2.056
2.019
1.807
1.943
1.921
2.103
−0.018
−0.028
0.004
5f∗
5g
1.53
1.24
1.41
1.05
1.23
1.07
1.20
1.25
1.28
1.17
1.67
1.70
1.73
1.64
2.14
2.31
2.06
2.34
2.58
1.539
1.261
1.313
1.199
1.059
1.065
1.004
0.971
1.083
1.075
1.775
1.402
1.409
1.891
1.904
2.134
2.165
2.461
2.480
−0.009
−0.021
0.097
5g∗
5h
5h
5i
5j
5k
0.029
−0.026
0.012
5i
−0.149
0.171
5j∗
5k
0.005
5l
0.036
−0.022
0.019
5l
−0.196
−0.279
0.197
5m∗
5n
5m
5n
5o
−0.201
0.004
0.018
5o∗
5p
0.095
−0.105
0.298
5p∗
5q
5q
5r
5s
5r
−0.296
−0.026
0.011
0.321
−0.251
0.236
0.176
5s∗
5t
5t
5u
0.023
5u∗
5v
5w
5x
0.007
5v
5w
5x
−0.105
0.029
−0.121
−0.023
0.10
e compound marked with ∗ was selected for test set.
e compound marked with ∗ was selected for test set.
80.000
20.000
20.000
80.000
Figure 3: CoMFA contour map for Amaranthus mangostanus L.
Figure 2: CoMFA contour map for Oryza sativa.
enhancing the inhibitory effect on Amaranthus mangostanus
L. Actually, compounds 5a–5o showed stronger inhibitory
effect than that of 5p–5r with morpholine tail and 5s–5x with
carboxylic acid on piperidine ring.
On the whole, the structural insights obtained from
molecular docking and 3D-QSAR contour maps are consis-
tent with the experimental data, indicating that the molecular
docking and the developed 3D-QSAR models are reliable
to some extent. e 3D-QSAR contour maps show that the
showed worse inhibitory effect than those of 5f and 5g. e
inhibitory activity on Oryza sativa may increase if electron-
positive groups were introduced.
In Figure 3, green region near benzene ring and blue
region near amino groups manifested that increasing the
size of substituent on benzene ring and importing electron-
positive group on tertiary amino part are beneficial for

Journal of Chemistry
7
electronic effect contributes to the strong herbicidal activity.
Introduction of electron-positive group to the amino group
of the test compounds may facilitate improving the inhibitory
effect on Oryza sativa and Amaranthus mangostanus.
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[12] K. Narayanan, M. Shanmugam, S. Jothivel, and S. Kabilan,
“Design, synthesis, spectral and biological evaluation of novel
1-allyl substituted 2,6-diphenylpiperidin-4-ones and its deriva-
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4. Conclusions
A series of benzophenone oxime ether derivatives with
tertiary amines were synthesized and characterized. ese
compounds exhibited good herbicidal activities to both
monocotyledon and dicotyledon. Based on the experimental
results, the combined 3D-QSAR modeling and molecular
docking analysis was performed with the data of Oryza
sativa and Amaranthus mangostanus L. Due to the insufficient
compounds structure diversity and variable influence factor,
the models were assumed to be predictive but not perfectly
reliable. However, these results threw a light on the research
and development on the oxime ethers with amino groups to
be herbicides.
Conflict of Interests
e authors declare that there is no conflict of interests
regarding the publication of this paper.
[13] T. Zhang, R. Xie, T. Zhang, X. Mei, J. Yang, and J. Ning, “Design,
synthesis and bioactivities of novel oxime ether derivatives,”
Journal of Pesticide Science, vol. 38, no. 2, pp. 88–90, 2013.
Authors’ Contribution
Jimei Ma and Mingwei Ma contributed equally to this paper.
[14] C. Fu, J. Pei, Y. Ning et al., “Synthesis and insecticidal activities
of novel pyrazole oxime ether derivatives with different substi-
tuted pyridyl rings,” Pest Management Science, vol. 70, no. 8, pp.
1207–1214, 2014.
[15] H. Dai, J. Liu, W. Miao et al., “Synthesis and biological activities
of novel pyrazole oxime ether derivatives containing pyridyl
ring,” Chinese Journal of Organic Chemistry, vol. 31, no. 10, pp.
1662–1667, 2011.
Acknowledgment
e financial support (Program nos. 2013PY121 and
2012BQ029) provided by the Fundamental Research Funds
for the Central Universities, China, is gratefully acknowl-
edged.
[16] H. Song, Y. Liu, L. Xiong, Y. Li, N. Yang, and Q. Wang,
“Design, synthesis, and insecticidal evaluation of new pyrazole
derivatives containing imine, oxime ether, oxime ester, and
dihydroisoxazoline groups based on the inhibitor binding
pocket of respiratory complex I,” Journal of Agricultural and
Food Chemistry, vol. 61, no. 37, pp. 8730–8736, 2013.
[17] Y.-Q. Xie, Z.-L. Huang, H.-D. Yan et al., “Design, synthesis,
and biological activity of oxime ether strobilurin derivatives
containing indole moiety as novel fungicide,” Chemical Biology
& Drug Design, vol. 85, no. 6, pp. 743–755, 2015.
[18] Y.-Q. Xie, Y.-B. Huang, J.-S. Liu et al., “Design, synthesis and
structure-activity relationship of novel oxime ether strobilurin
derivatives containing substituted benzofurans,” Pest Manage-
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[19] L. Jiang, C. Chen, Y. Zhou, Q. Chen, and G. Yang, “Synthesis and
herbicidal activities of novel 1,2,4-triazolo[1,5-a]-pyrimidine
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