Design, synthesis and biological evaluation of 1H-pyrazole-5-carboxamide derivatives as potential fungicidal and insecticidal agents

Article abstract of DOI:10.1007/s11696-017-0198-4

A series of novel 1H-pyrazole-5-carboxamide compounds containing the phenyl thiazole moiety were designed and synthesized by a facile method, and their structures were characterized by ¹H NMR, mass spectrometry and elemental analysis. Bioassay results showed that most of the title compounds showed potent fungicidal activities against Erysiphe graminis and insecticidal activity against Aphis fabae. Especially, compound 9b has EC₅₀ values of 3.04 mg/L against Erysiphe graminis, of which the fungicidal activity is better than that of the commercial fungicide Thifluzamide and Azoxystrobinare; compound 9l has LC₅₀ values of 3.81 mg/L against Aphis fabae, which was comparable with the commercial insecticide Tolfenpyrad. It is suggested that 1H-pyrazole-5-carboxamide compounds containing the phenyl thiazole moiety could be considered as a precursor structure for further design of pesticides. Graphical Abstract: A series of novel 1H-pyrazole-5-carboxamide compounds containing the phenyl thiazole moiety were designed and synthesized by a facile method, and their structures were characterized by ¹H NMR, mass spectrometry and elemental analysis. Bioassay results showed that most of the title compounds showed potent fungicidal activities against Erysiphe graminis and insecticidal activity against Aphis fabae. Especially, compound 9b has EC₅₀ values of 3.04 mg/L against Erysiphe graminis, of which the fungicidal activity is better than that of the commercial fungicide Thifluzamide and Azoxystrobinare; compound 9l has LC₅₀ values of 3.81 mg/L against Aphis fabae, which was comparable with the commercial insecticide Tolfenpyrad. It is suggested that 1H-pyrazole-5-carboxamide compounds containing the phenyl thiazole moiety could be considered as a precursor structure for further design of pesticides.[Figure not available: see fulltext.]

Full text of DOI:10.1007/s11696-017-0198-4

Chem. Pap.
DOI 10.1007/s11696-017-0198-4
ORIGINAL PAPER
Design, synthesis and biological evaluation of 1H-pyrazole-5-
carboxamide derivatives as potential fungicidal and insecticidal
agents
Danling Huang1,2,3 Mingzhi Huang2,3 Weidong Liu2,3 Aiping Liu2,3
•
•
•
•
Xingping Liu2,3 Xiaoyang Chen1,2,3 Hui Pei2,3 Jiong Sun2,3 Dulin Yin1
Xiaoguang Wang1,2,3
•
•
•
•
•
Received: 17 February 2017 / Accepted: 10 May 2017
Ó Institute of Chemistry, Slovak Academy of Sciences 2017
Abstract A series of novel 1H-pyrazole-5-carboxamide
compounds containing the phenyl thiazole moiety were
designed and synthesized by a facile method, and their
structures were characterized by 1H NMR, mass spec-
trometry and elemental analysis. Bioassay results showed
that most of the title compounds showed potent fungicidal
activities against Erysiphe graminis and insecticidal
activity against Aphis fabae. Especially, compound 9b has
EC50 values of 3.04 mg/L against Erysiphe graminis, of
which the fungicidal activity is better than that of the
commercial fungicide Thifluzamide and Azoxystrobinare;
compound 9l has LC50 values of 3.81 mg/L against Aphis
fabae, which was comparable with the commercial insec-
ticide Tolfenpyrad. It is suggested that 1H-pyrazole-5-
carboxamide compounds containing the phenyl thiazole
moiety could be considered as a precursor structure for
further design of pesticides.
Graphical Abstract A series of novel 1H-pyrazole-5-
carboxamide compounds containing the phenyl thiazole
moiety were designed and synthesized by a facile method,
1
and their structures were characterized by H NMR, mass
spectrometry and elemental analysis. Bioassay results
showed that most of the title compounds showed potent
fungicidal activities against Erysiphe graminis and insec-
ticidal activity against Aphis fabae. Especially, compound
9b has EC50 values of 3.04 mg/L against Erysiphe gra-
minis, of which the fungicidal activity is better than that of
the commercial fungicide Thifluzamide and Azoxys-
trobinare; compound 9l has LC50 values of 3.81 mg/L
against Aphis fabae, which was comparable with the
commercial insecticide Tolfenpyrad. It is suggested that
1H-pyrazole-5-carboxamide compounds containing the
phenyl thiazole moiety could be considered as a precursor
structure for further design of pesticides.
& Dulin Yin
dulinyin@126.com
& Xiaoguang Wang
xxggWang@163.com
1
National and Local Joint Engineering Laboratory for New
Petro-chemical Materials and Fine Utilization of Resources,
Key Laboratory of Chemical Biology and Traditional
Chinese Medicine Research (Ministry of Education of
China), College of Chemistry and Chemical Engineering,
Hunan Normal University, Changsha 410081, China
2
Hunan Province Key Laboratory for Agrochemicals,
Changsha 410014, China
Keywords Pyrazole carboxamide Á Phenyl thiazole Á
Bioactivity Á Structure–activity relationships
3
Hunan Haili Chemical Industry Co., Ltd, Changsha 410007,
China
123

Chem. Pap.
Introduction
Experimental section
Chemistry
With the growing population, the demand for crops is
increasing sharply. However, plant diseases from fungus and
insects are unavoidable, greatly threatening crop production
and limiting the development of agriculture worldwide
(Fisher et al. 2011). Thus, to develop lower toxicity and
efficient pesticides appears particularly important and
urgent. Although a great variety of fungicides with various
chemical structures have been successfully developed in the
past decades (Pravin 2012), conventional fungicides emerge
fungicide-resistant gradually after repeated use (Price et al.
2015; Grimmer et al. 2015). Therefore, development of
novel and practical reagents becomes necessary.
Melting points (mp) were measured on a WPS-1B melting-
point apparatus (made in Shanghai Physical Optics
1
Instrument Plant) and are uncorrected; H NMR spectra
were recorded in CDCl3 with a Varian INOVA-300, using
TMS as internal standard; high resolution mass spectra
were acquired using an Agilent 5973-6890 gas chro-
matography–mass spectrometer (GC–MS) and an Agilent
1100 series liquid chromatography–mass spectrometer
(LC–MS). Column chromatography was performed using
200–300 mesh silica gels. The solvents and reagents were
used as received or were dried prior to use as needed.
The general synthetic methods for compounds 9a–v are
shown in Scheme 1. Representative procedures are given
below. Yields were not optimized. Every other compound
was synthesized in a manner similar to that used for the
representatives, and every target compound was identified
The pyrazole ring plays a vital role in the agrochemical
field which discovered its significance due to its versatile
biological activities and flexible substituent sites (Sener
et al. 2004). In particular, pyrazole carboxamide deriva-
tives have become a hotspot study in pesticides over the
past decades because of their low toxicity and high
bioactivity (Rainer and Christoph 1995; Itaru et al. 1988).
Numerous pyrazole carboxamide derivatives have been
developed as pesticides up to now. Among these com-
pounds, some 1H-pyrazole-5-carboxamide derivatives dis-
play remarkable bioactivity, such as Chloantraniliprole
(Lahm et al. 2007), Tebufenpyrad (Mitsubishi Chemical
1995) and Tolfenpyrad (Li et al. 1997). Thiazole ring also
has the status of equal importance in agrochemical field.
There are many thiazole derivatives being developed as
commercial products, such as ethaboxam (Kim et al. 2004)
and trifluzamide (Baba et al. 2000). In the previous work, a
series of novel 1H-pyrazole-5-carboxamide and thiazole
derivatives had been designed and synthesized, but their
bioactivities were unsatisfactory (Huang et al. 2016; Liu
et al. 2014).
1
and verified by H NMR, MS and elemental analyses.
Synthesis of ethyl 2, 4-dioxovalerate (1a) and its
analogues (1b–e)
Sodium ethylate (30.0 g, 0.45 mol) was added into 300 mL
of anhydrous ethanol and stirred evenly in ice-salt baths.
Then the mixture solution of acetone (14.7 g, 0.3 mol) and
diethyl oxalate (46.7 g, 0.32 mol) was added dropwise into
sodium ethoxide–ethanol solution to keep the reaction
temperature below -5 °C for 3 h. The mixture was poured
into ice water. After using hydrochloric acid (1 mol/L) to
keep the pH around 4, the aqueous phase was extracted
with ethyl acetate (EA). The organic layer was washed
twice with 150 mL water and dried over Na2SO4, filtered,
and concentrated under reduced pressure; 46.5 g (94%
yield, 96% purity) yellow liquid (1a) was obtained. With-
out further purification, compound 1a was used in the next
reaction. 1b–h were obtained in analogous procedures.
To search for compounds with excellent biological
activities, a novel structure containing pyrazole carbox-
amide and thiazole was designed and an optimization pro-
gram was carried out by modifying moiety A and B (Fig. 1).
Here are reported the design and syntheses of a series of 22
unreported 1H-pyrazole-5-carboxamide derivatives. Most
of target compounds showed remarkable fungicidal and
insecticidal activity. In particular, the fungicidal activity
level of compound 9b [5-Ethyl-2-methyl-2H-pyrazole-3-
carboxylic acid (2-phenyl-thiazol-4-ylmethyl)-amide] is
better than that of the commercial fungicides, Thifluzamide
and Azoxystrobinare, and compound 9l [5-Ethyl-2-methyl-
2H-pyrazole-3-carboxylic acid (2-p-tolyl-thiazol-4-yl-
methyl)-amide] possesses commercial levels of insecticidal
activity comparable to that of commercial amide insecti-
cides such as Tolfenpyrad. Besides, their structure–activity
relationship has been studied.
Synthesis of ethyl 3-methyl-1H-pyrazole-5-
carboxylate (2a) and its analogues (2b–f)
Methylhydrazine (0.38 mol) was added slowly into
300 mL of 1a (46.5 g, 96% purity) in anhydrous ethanol
below -5 °C. Then the solution was stirred acutely for 2 h.
The solvent was removed under reduced pressure and the
aqueous phase was extracted with EA. The organic layer
was washed twice with 150 mL water and dried over
Na2SO4, filtered, and concentrated under reduced pressure;
39.3 g (92% yield, 90% purity) yellow oil (2a) was
obtained. Without further purification, compound 2a was
123

Chem. Pap.
Fig. 1 Design strategy of the
target compounds
Scheme 1 Synthetic pathways for the target compounds 9a–v
used in the next reaction. 2b–f was prepared in an analo-
gous method.
under reduced pressure and the mixture was poured into ice
water. Then the aqueous phase was extracted with EA. The
organic layer was washed twice with water and dried over
Na2SO4, filtered, and concentrated under reduced pressure;
9.07 g yellow solid was obtained. Then 5% Pd/C catalyst
(0.54 g) and the yellow solid were, respectively, added to a
stirred mixture of ethanol (50 mL) and water (10 mL),
which was carried out in hydrogen atmosphere at room
temperature for 6 h. After the catalyst was filtered, the
mixture solutions were poured into water and then the
aqueous phase was extracted with EA. The organic layer
was washed with 50 mL water and dried over Na2SO4,
Synthesis of ethyl 1, 3, 4-trimethyl-1H-pyrazole-5-
carboxylate (2g) and its analogues (2h)
Paraformaldehyde (3.6 g, 0.12 mol), 1,4-dioxane (100 mL)
and 2a (10 g, 0.06 mol) were mixed uniformly. Then
H2SO4 (0.6 g, 0.006 mol) and concentrated hydrochloric
acid (12 g, 12 mol) were added to a stirred mixture and
heated to reflux. After the reactant was undetected by thin-
layer chromatography (TLC), the solvent was removed
123

Chem. Pap.
filtered, and concentrated under reduced pressure; 9.07 g
(50% yield, 60% purity) brown liquid was obtained. The
crude product was separated by silica gel column chro-
matography with petroleum ether-ethyl acetate (15:1/10:1
by volume); 6.04 g (98%) white oil (2g) was obtained. 2h
was obtained in analogous procedures.
After 2 h under reflux, the solvent was removed under
reduced pressure. 4a was obtained and without further
purification and calculating the yield, next reaction was
carried out immediately. The analogues 4b–p were pre-
pared in a similar procedure.
Synthesis of 4-(chloromethyl)-2-arlylthiazole (6a)
and its analogues (6b–e)
Synthesis of ethyl 1, 3-dimethyl-4-chlorine-1H-
pyrazole-5-carboxylate (2i) and its analogues (2j)
A mixture of thiobenzamide 5a (20.5 g, 150 mmol) and
1,3-dichloroacetone (21.6 g, 170 mmol) dissolved in
anhydrous 150 ml EtOH and 75 ml THF (20 mL) was
stirred at reflux temperature for 6 h. The solvent was
removed under reduced pressure and the aqueous phase
was extracted with EA. The organic layer was washed
twice with 150 mL water and dried over Na2SO4, and fil-
tered; 28.0 g (84% purity) yellow oil (6a) was obtained.
Yield: 75%. Without further purification, the product was
used in the next reaction. The analogues (6b–e) could be
synthesized by the method similar to that described in the
synthesis of 6a.
Thionyl chloride (8.04 g, 0.06 mol) was slowly added to a
stirred mixture of 2a (10 g, 0.06 mol) and dichloroethane
(50 mL) below 5 °C. Then the solution was stirred under
reflux for 2 h. The solvent was removed under reduced
pressure and the mixture was poured into 30 mL saturated
NaCl solution. Then the aqueous phase was extracted with
50 mL EA. The organic layer was washed twice with water
and dried over Na2SO4, filtered, and concentrated under
reduced pressure; 9.99 g (95% yield, 88% purity) brown
liquid (2i) was obtained. 2j was obtained in analogous
procedure.
Synthesis of ethyl 1-methyl-3-ethyl-4-bromine-1H-
pyrazole-5-carboxylate (2k)
Synthesis of 4-(chloromethyl)-2-arlylthiazole (8a)
and its analogues (8b–e)
Br2 (8.0 g, 0.05 mol) was dropwise added to a stirred
mixture of 3a (9.1 g, 0.05 mol) and CCl4 (100 mL) under
reflux for 4 h. The solvent was removed under reduced
pressure and the mixture was poured into NaHCO3 solu-
tion. Then the aqueous phase was extracted with EA. The
organic layer was washed twice with 50 mL water and
dried over Na2SO4, filtered, and concentrated under
reduced pressure; 10.17 g (73% yield, 93% purity) brown
liquid (2k) was obtained.
To a solution of 6a (0.045 mol) in 100 mL N,N-
dimethylformamide (DMF), potassium phthalimide
(0.05 mol) was added in portions. After the mixture was
stirred at 80 °C for 5 h, the mixture was poured into ice
water and the precipitate was collected by filtration and
washed with water; 7a was obtained as brown solid. Then
7a was mixed with 200 mL ethanol and hydrazine hydrate
(80%, 6.25 g, 0.1 mol). After 5 h under reflux, the pre-
cipitate was separated by filtration and the solvent of fil-
trate was removed under reduced pressure. Then the
mixture was poured into ice water and the aqueous phase
was extracted with 50 mL EA. The organic layer was
washed twice with 50 mL water and dried over Na2SO4,
filtered, and concentrated under reduced pressure; 6.0 g
(70.1% yield, 82% purity) 8a was obtained as brown oil.
Without further purification, the product was used in the
next reaction. The analogues (8b–e) could be synthesized
by the similar method.
Synthesis of 1, 3-dimethyl-1H-pyrazole carboxylic
acid (3a) and its analogues (3b–p)
2a (0.05 mol) was added to a stirred mixture of NaOH
(6.0 g, 0.15 mol) and water (100 mL). After 4 h under
80 °C, the mixture was poured into ice water and the pH
was adjusted to acidic. Then 10% HCl was slowly added to
the solutions until a large amount of solids precipitated.
After filtration, the solids were dried; 4.6 g (92% purity)
white solid (3a) was obtained. Yield 60%; GC–MS (EI,
70Ev) (m/z 140 (M?). 3b–p were synthesized in a similar
procedure.
Synthesis of 1, 3-dimethyl-N-((2-phenylthiazol-4-
yl)methyl)-1H-pyrazole-5-carboxamide (9a) and its
analogues (9b–v)
Synthesis of 1,3-dimethyl-1H-pyrazole acyl chloride
(4a) and its analogues (4b–p)
4a (0.01 mol) was added in drops into a solution of 8a
(0.01 mol) and triethylamine (0.02 mol) in THF (20 mL)
under 0 °C, and the reaction mixture was stayed overnight.
Then the mixture was poured into Na2CO3 solution and
aqueous phase was extracted with EA. The combined ether
3a (0.01 mol) and thionyl chloride (2.95 g, 0.025 mol)
were successively added to 15 ml 1, 2-dichloroethane.
123

Chem. Pap.
Table 1 Chemical structures, physical characteristics, yield, and bioactivities of compounds 9a–v
Comp Chemical structure
Yielda
(%)
Formula
mp (°C)
Inhibition of Erysiphe
graminis (%)
Mortality of Aphis fabae
(%)
Z
R1
R2
R3
500
(ppm)
100
(ppm)
50 200
(ppm) (ppm)
50 12.5
(ppm) (ppm)
9a
9b
9c
9d
Z-1 CH3
Z-1 CH3
Z-1 CH3
Z-1 CH3
H
H
H
H
CH3
38
43
C16H16N4OS
C17H18N4OS
C18H20N4OS
C18H18N4OS
105.7–106.2 98
95
85
48
35
98
40
27
35
68
15
17
CH2CH3
Oil
100
100
90
100
80
100
91
CH(CH3)2 36
34
98.9–99.9
Oil
100
85
86
85
76
9e
9f
Z-1 CH3
Z-1 CH3
Z-1 CH3
Z-1 CH3
Z-1 CH2CH3
Z-1 Z-1
CH3 CH3
18
20
30
28
40
21
42
42
18
40
31
38
39
33
41
43
36
28
C17H18N4OS
C18H20N4OS
150.5–151.2 85
135.6–136.7 30
70
50
40
50
NTb
NT
0
50
30
10
30
NT
NT
0
99
88
40
60
57
75
4
CH3 CH2CH3
100
100
100
7
100
100
100
4
9g
9h
9i
Cl
Br
H
CH3
C16H15ClN4OS 136.8–137.5 50
C17H17BrN4OS 147.7–149.8 40
CH2CH3
CH3
C17H18N4OS
C21H18N4OS
C17H18N4OS
C18H20N4OS
C19H22N4OS
Oil
20
9j
H
CH3
128.3–129.1 70
127.3–129.3 90
101.7–102.6 86
117.1–118.1 90
NT
96
NT
51
NT
17
70
100
11
56
27
50
NT
NT
20
64
6
9k
9l
Z-2 CH3
Z-2 CH3
Z-2 CH3
Z-3 CH3
Z-3 CH3
Z-4 CH3
Z-4 CH3
Z-4 CH3
Z-5 CH3
Z-5 CH3
Z-5 CH3
Z-6 CH3
H
CH3
H
CH2CH3
NT
33
NT
99
99
60
30
100
0
NT
24
NT
94
90
49
0
100
100
75
88
9m
9n
9o
9p
9q
9r
9s
9t
CH3 CH2CH3
100
55
H
CH2CH3
CH3
C17H17ClN4OS 83.1–85.5
75
Cl
H
C16H14Cl2N4OS 136.6–137.6 100
C16H15ClN4OS 123.1–124.0 100
C17H17ClN4OS 118.6–119.6 90
C17H16Cl2N4OS 138.8–139.3 91
87
79
CH3
86
53
H
CH2CH3
CH2CH3
CH3
100
NT
NT
72
91
Cl
H
NT
NT
27
C17H18N4O2S
C18H20N4O2S
139.6–140.1 100
102.6–103.1 90
92
NT
NT
NT
H
CH2CH3
CH2CH3
CH3
9u
9v
a
Cl
Cl
C18H19ClN4O2S 136.0–136.2 91
C17H17ClN4O2S 155.4–155.8 70
0
100
40
86
NT
15
Yield value is the cumulative yield from compounds 1
b
NT means no test because of its low activity in higher test concentration
extracts were dried and filtered, and the solvent was
removed. The residue material was separated by silica gel
column chromatography with petroleum ether-ethyl acetate
(10:1/5:1 by volume) as eluant to yield 9a as brown solid;
1H NMR (CDCl3) 2.259 (s, 3H, CH3), 4.112 (s, 3H, CH3),
4.699 (dd, J = 5.7, 0.9 Hz, 2H, CH2), 6.346 (s, 1H, Pyra-
zole H), 6.765 (bs, 1H, NH), 7.205 (s, 1H, Thiazole H),
7.432–7.494 (m, 3H, Ph H), 7.909–7.969 (m, 2H, Ph H);
13C NMR (CDCl3, 75 MHz) d: 168.8, 159.8, 153.2, 146.5,
135.4, 133.1, 129.9, 128.9, 126.3, 115.4, 105.8, 39.4, 38.7,
13.1; GC–MS M? = 312, base peak: 189. 9b–v could be
synthesized by the method similar to that described in the
synthesis of 9a, the yield of 9a–9v for this step was more
than 90%. Structures of 9a–9v were supported by 1H NMR,
elemental analysis and GC–MS shown in Table 4. Due to
the structural similarity of compounds 9, only some
representative compounds with high bioactivity, such as
9a, 9b and 9l, were analyzed and confirmed by 13C NMR.
Biological assay
Preparation of test compounds
Stock solution of every test compound was prepared in
DMF at a concentration of 1.0 g/L and then diluted to the
required test concentrations (12.5–500 mg/L) with water
containing Tween 80 (0.4 mg/L).
Insecticidal activity against Aphis fabae
The horse bean seedlings with Aphis fabae were dipped in
the test solutions for 5–10 s, then allowed to dry with filter
123

Chem. Pap.
Table 2 EC50 values of the
target compounds against
Erysiphe graminis
Compound
Regression equation
Correlation
EC50 (mg/L)
95% confidence limit
(mg/L)
9a
y = 3.6423 ? 1.7357x
y = 4.3242 ? 1.3979x
y = 4.0191 ? 1.5518x
y = 4.0392 ? 1.4244x
y = 3.3609 ? 1.2372x
y = 3.5540 ? 1.4271x
y = 4.2673 ? 1.4582x
y = 4.0340 ? 1.4743x
0.9916
0.9412
0.9927
0.9665
0.9889
0.9898
0.988
6.06
3.04
4.28
4.73
21.13
10.31
3.19
4.52
5.13–7.15
2.66–3.47
2.89–6.37
3.27–6.82
13.08–34.13
7.18–14.80
2.65–3.81
3.29–6.21
9b
9c
9d
9o
9s
Azoxystrobinare
Thifluzamide
0.9896
Table 3 LC50 values of the target compounds against Aphis fabae
paper, transferred to a beaker (100 mL) containing water
(10 mL) and kept at 25 °C. Each assay contained three
replications. After 24 h, mortality was recorded. The test
was run three times, and results were averaged.
Compound
Regression equation
Correlation LC50 (mg/L)
9l
y = 3.9186 ? 1.8605x 0.9975
y = 3.6347 ? 1.6176x 0.9947
y = 3.6202 ? 1.7214x 0.9651
3.81
6.98
6.33
3.16
9m
9u
Fungicidal activity
Tolfenpyrad y = 4.1384 ? 1.7231x 0.9708
The fungicidal activities were tested according to our
previously reported method (Liu et al. 2008).
the activity level of target compounds, parts of compounds
with high fungicidal activities were singled out to calculate
the regression equation, and the concentration for 50% of
maximal effect (EC50) value for these compounds is shown
in Table 2. The activity of commercial fungicides such as
Thifluzamide and Azoxystrobinare is also presented in
Table 2. It is noteworthy that 9b, 9c, and 9d exhibited a
significant inhibition effect against E. Graminis. The
fungicidal activity level of compounds 9c and 9d, for
which the EC50 values were 4.28 and 4.73 mg/L, respec-
tively, was similar to that of commercial fungicide Thi-
fluzamide and Azoxystrobinare. In particular, compound
9b has EC50 values of 3.04 mg/L against Erysiphe gra-
minis, which are better than those of the commercial
fungicides, Thifluzamide and Azoxystrobinare.
Results and discussion
Synthesis
The synthesis pathway is shown in Scheme 1. Their
structures were confirmed by spectroscopic and elemental
analysis. The synthesis and characterization of intermedi-
ates 1–3 were according to our previously reported meth-
ods (Huang et al. 2016), which were in accordance with
literature (Pazenok et al. 2012; Yoshida, et al. 1995; Mu¨ller
and Matzke 2001). The chemical structures, physical
characteristics, and yields of target compounds 9a–v are
1
presented in Table 1. MS and H NMR data are listed in
Table 4. The observed molecular weight for each com-
pound of 9a–v was as expected in the MS analysis. The fact
that the target compounds have been prepared in nice yield
and purity successfully indicates that the synthesis pathway
shown in Scheme 1 is reasonable and available.
Insecticidal activity
The mortality data of 9a–v against A. fabae are shown in
Table 1. It indicated that most of the compounds of 9 have
excellent insecticidal activity against A. fabae at 200 mg/L,
parts of them still display potential insecticidal activity at
lower test concentration. For example, the mortality of 9b,
9f–9h, 9l, 9m, 9q and 9u against A. fabae at 200 mg/L was
100%, and compounds 9b, 9f–9h, 9l, 9m, 9o and 9u have
C50% insecticidal activity at 12.5 mg/L. Some compounds
with better insecticidal activity were singled out to further
evaluate the activity, and the median lethal concentration
(LC50) value of these compounds is presented in Table 3.
To our amazement, 9l has LC50 values of 3.81 mg/L
against A. fabae, and the insecticidal activity level was
comparable with the commercial insecticide, Tolfenpyrad.
Fungicidal activity
Table 1 shows the preventive activities of 9a–v against
Erysiphe graminis. It is obvious that most of the com-
pounds
9 exhibit ideal fungicidal activity against
E. graminis at 500 mg/L, some of them display high
fungicidal activity at 50 mg/L. For instance, compounds
9a, 9b, 9c, 9o, 9p and 9s have C95% fungicidal activity at
100 mg/L, compounds 9b, 9o, 9p and 9s still have C90%
fungicidal activity at 50 mg/L. In order to further evaluate
123

Chem. Pap.
Table 4 Elemental analysis, MS and NMR data of 9a–9v
Comp Elemental analysis
1H NMR(d); MS(m/e)
9a
Calcd: C, 61.52; H, 5.16; N, 17.93; found: 1H NMR (CDCl3) 2.259 (s, 3H, CH3), 4.112 (s, 3H, CH3), 4.699 (dd, J = 5.7, 0.9 Hz, 2H,
C, 61.41; H, 5.13; N, 18.03
CH2), 6.346 (s, 1H, Pyrazole H), 6.765 (bs, 1H, NH), 7.205 (s, 1H, Thiazole H),
7.432–7.494 (m, 3H, Ph H), 7.909–7.969 (m, 2H, Ph H). 13C NMR (CDCl3, 75 MHz) d
168.8, 159.8, 153.2, 146.5, 135.4, 133.1, 129.9, 128.9, 126.3, 115.4, 105.8, 39.4, 38.7,
13.1; GC-MS M? = 312, base peak: 189
9b
Calcd: C, 62.55; H, 5.56; N, 17.16; found: 1H NMR (CDCl3) 1.196 (t, J = 7.5 Hz, 3H, CH3), 2.582 (q, J = 7.5 Hz, 2H, CH2), 4.120
C, 62.62; H, 5.57; N, 17.10
(s, 3H, CH3), 4.691 (dd, J = 5.4, 0.6 Hz, 2H, CH2), 6.376 (s, 1H, Pyrazole H), 6.906
(bs,1H,NH), 7.206 (t, J = 0.9 Hz, 1H, Thiazole H), 7.435–7.467 (m, 3H, Ph H),
7.905–7.938 (m, 2H, Ph H). 13C NMR (CDCl3, 75 MHz) d 168.7, 159.8, 153.2, 152.6,
135.2, 132.9, 130.0, 128.8, 126.2, 115.4, 104.5, 39.2, 38.6, 20.9, 13.1; HPLC-MS Pos
[M?1]? = 327
9c
9d
9e
9f
Calcd: C, 63.50; H, 5.92; N, 16.46;found: C, 1H NMR (CDCl3)1.235 (d, J = 6.9 Hz, 6H, 2CH3), 2.937–2.984 (m, 1H, CH), 4.130 (s,
63.44; H, 5.98; N, 16.53
3H, CH3), 4.716 (dd, J = 5.4, 0.6 Hz, 2H, CH2), 6.387 (s, 1H, Pyrazole H), 6.828 (bs,
1H, NH), 7.196 (s, 1H, Thiazole H), 7.463–7.476 (m, 3H, Ph H), 7.939–7.971 (m, 2H,
Ph H).GC–MS M? = 340, base peak: 189
Calcd: C, 63.88; H, 5.36; N, 16.56; found: H NMR (CDCl3) 0.873–0.937 (m, 4H, 2CH2), 1.865–1.921 (m, 1H, CH), 4.101 (s, 3H,
C, 63.91; H, 5.29; N, 16.53
CH3), 4.694 ( dd, J = 5.4, 0.9 Hz, 2H, CH2), 6.227 (s, 1H, Pyrazole H), 6.767 (bs, 1H,
NH), 7.210 (s, 1H, Thiazole H), 7.434–7.485 (m, 3H, Ph H), 7.928–7.964 (m, 2H, Ph
H). GC–MS M? = 338
Calcd: C, 62.55; H, 5.56; N, 17.16, found: C, 1H NMR (CDCl3) 2.197 (s, 3H, CH3), 2.211 (s, 3H, CH3), 4.031 (s, 3H, CH3), 4.742 (dd,
62.60; H, 5.49; N, 17.17
J = 5.4, 0.6 Hz, 2H, CH2), 6.715 (bs, 1H, NH), 7.198 (d, J = 0.6 Hz, 1H, Thiazole H),
7.399–7.476 (m, 3H, Ph H), 7.898–7.958 (m, 2H, Ph H). GC–MS M? = 326, base peak:
189
Calcd: C, 63.50; H, 5.92; N, 16.46; found: 1H NMR (CDCl3) 1.183 (t, J = 7.5 Hz 3H, CH3), 2.228 (s, 3H, CH3), 2.550 (q, J = 7.8 Hz,
C, 63.54; H, 5.88; N, 16.43
2H, CH2), 4.041 (s, 3H, CH3), 4.750 (dd, J = 5.4, 0.6 Hz, 2H, CH2), 6.705 (bs, 1H, NH),
7.209 (s, 1H, Thiazole H), 7.431–7.481 (m, 3H, Ph H), 7.900–7.955 (m, 2H, Ph H).
GC–MS M? = 340, base peak: 189
9g
9h
Calcd: C, 55.41; H, 4.36; N, 16.15; found: 1H NMR (CDCl3) 2.252 (s, 3H, CH3), 4.144 (s, 3H, CH3), 4.779 (dd, J = 5.1, 0.6 Hz,
C,55.47; H, 4.29; N, 16.20
2H,CH2), 7.209 (s, 1H, Thiazole H), 7.429–7.476 (m, 3H, Ph H), 7.579 (bs, 1H, NH),
7.923–7.968 (m, 2H, Ph H). GC–MS M? = 346, base peak: 189
Calcd: C, 50.38; H, 4.23; N, 13.82; found: 1H NMR (CDCl3) 1.218 (t, J = 7.5 Hz, 3H, CH3), 2.604 (q, J = 7.5 Hz 2H, CH2), 4.152 (s,
C, 50.31; H, 4.29; N, 13.77
3H, CH3), 4.784 (dd, J = 5.4, 0.6 Hz, 2H, CH2), 7.220 (s, 1H, Thiazole H), 7.415–7.474
(m, 3H, Ph H), 7.548 (bs, 1H, NH), 7.925–7.970 (m, 2H, Ph H). GC–MS M? = 406,
base peak: 189
9i
Calcd: C, 62.55; H, 5.56; N, 17.16; found: 1H NMR (CDCl3) 1.401 (t, J = 7.5 Hz, 3H, CH3), 2.261 (s, 3H, CH3), 4.498 (q, J = 7.2
C, 62.51; H, 5.62; N, 17.13
Hz, 2H, CH2), 4.696 (dd, J = 5.7, 0.9 Hz, 2H, CH2), 6.329 (s, 1H, Pyrazole H), 6.806
(bs, 1H, NH), 7.195 (d, J = 0.6 Hz, 1H, Thiazole H), 7.425–7.476 (m, 3H, Ph H),
7.906–7.955 (m, 2H, Ph H). GC–MS M? = 326, base peak: 189
9j
9k
9l
Calcd: C, 67.36; H, 4.85; N, 14.96; found: 1H NMR (CDCl3) 2.337 (s, 3H, CH3), 4.615 (dd, J = 5.4, 0.3 Hz, 2H, CH2), 6.580 (s, 1H,
C, 67.32; H, 4.89; N, 14.89
Pyrazole H), 6.626 (bs, 1H, NH), 7.105 (s, 1H, Thiazole H), 7.274–7.474 (m, 8H, Ph
H), 7.865–7.915 (m, 2H, Ph H). GC–MS M? = 374, base peak: 189
Calcd: C, 62.55; H, 5.56; N, 17.16; found: 1H NMR (CDCl3) 2.257 (s, 3H, CH3), 2.416(s, 3H, CH3), 4.116(s, 3H, CH3), 4.714 (d,
C, 62.48; H, 5.62; N, 17.22
J=5.7 Hz, 2H, CH2), 6.412 (s, 1H, pyrazole H), 7.219 (s, 1H, thiazole H), 7.262 (d,
J=10.2 Hz, 2H, Ph H), 7.871 (d, J=8.1 Hz, 2H, Ph H). GC-MS M?=326, base peak: 203
Calcd: C, 63.50; H, 5.92; N, 16.46; found: 1H NMR (CDCl3) 2.199 (t, J = 7.5 Hz, 3H, CH3), 2.403 (s, 3H, CH3), 2.587 (q, J = 7.8
C, 63.55; H, 5.87; N, 16.51
Hz, 2H, CH2), 4.124 (s, 3H, CH3), 4.675 (dd, J = 6.0, 0.6 Hz, 2H, CH2), 6.396 (s, 1H,
Pyrazole H), 7.047 (t, J = 5.4 Hz, 1H, NH), 7.197 (s, 1H, Thiazole H), 7.240–7.269(m,
2H, Ph H), 7.777–7.818 (m, 2H, Ph H). 13C NMR (CDCl3, 75 MHz) d 174.0, 169.2,
159.9, 152.9, 140.5, 135.4, 130.4, 129.6, 126.4, 115.1, 104.4, 39.3, 38.8, 21.1, 20.9,
13.7; GC–MS M? = 340, base peak: 203
9m
9n
Calcd: C, 64.38; H, 6.26; N, 15.81; found: 1H NMR (CDCl3) 1.180 (t, J = 7.8 Hz, 3H, CH3), 2.223 (s, 3H, CH3), 2.405 (s, 3H, CH3),
C, 64.31; H, 6.29; N, 15.77
2.545 (q, J = 7.5 Hz, 2H, CH2), 4.032 (s, 3H, CH3), 4.745 (d, J = 5.1 Hz, 2H, CH2),
6.798 (bs, 1H, NH), 7.186 (s, 1H, Thiazole H), 7.247–7.274 (m, 2H, Ph H), 7.826 (d, J
= 7.8 Hz, 2H, Ph H). GC–MS M? = 354, base peak: 203
Calcd: C, 56.58; H, 4.75; N, 15.53; found: 1H NMR (CDCl3) 1.027 (t, J = 7.5 Hz, 3H, CH3), 2.594 (q, J = 1.5 Hz, 2H, CH2), 4.135
C, 56.61; H, 4.67; N, 15.49
(s, 3H, CH3), 4.747 (d, J = 5.7 Hz, 2H, CH2), 6.369 (s, 1H, pyrazole H), 6.778 (bs, 1H,
NH), 7.345–7.536 (m, 3H, Ph H), 7.492 (s, 1H, Thiazole H), 8.169–8.202 (m, 1H, Ph
H). HPLC-MS Pos [M?1]? = 361
123

Chem. Pap.
Table 4 continued
Comp Elemental analysis
1H NMR(d); MS(m/e)
9o
9p
9q
Calcd: C, 50.40; H, 3.70; N, 14.69; found: 1H NMR (CDCl3) 2.248 (s, 3H, CH3), 4.140 (s, 3H, CH3), 4.838 (d, J = 5.4 Hz, 2H, CH2),
C, 50.43; H, 3.78; N, 14.64
7.378–7.419 (m, 3H, Ph H), 7.514 (s, 1H, Thiazole H), 7.641 (bs, 1H, NH), 8.307 (d, J
= 9.2 Hz, 1H, Ph H). HPLC–MS Pos [M?1]? = 381
Calcd: C, 55.41; H, 4.36; N, 16.15; found: 1H NMR (CDCl3) 2.262 (s, 3H, CH3), 4.121 (s, 3H, CH3), 4.703 (d, J = 5.7 Hz, 2H, CH2),
C, 55.46; H, 4.29; N, 16.20
6.361 (s, 1H, Pyrazole H), 6.792 (bs, 1H, NH), 7.240 (s, 1H, Thiazole H), 7.415–7.460
(m, 2H, Ph H), 7.874–7.920 (m, 2H, Ph H). GC–MS M? = 346, base peak: 223
Calcd: C, 56.58; H, 4.75; N, 15.53; found: 1H NMR (CDCl3) 1.210–1.262 (m, 3H, CH3), 2.597 (q, J = 7.7 Hz, 2H, CH2), 4.130 (s,
C, 56.55; H, 4.69; N, 15.63
3H, CH3), 4.705 (dd, J = 6.0, 0.9 Hz, 2H, CH2), 6.378 (s, H, pyrazole H), 6.753 (bs, 1H,
NH), 7.242 (s, 1H, Thiazole H), 7.422 (d, J = 8.7 Hz, 2H, Ph H), 7.880 (d, J = 8.7 Hz,
2H, Ph H). GC–MS M? = 361, base peak: 224
9r
Calcd: C, 51.65; H, 4.08; N, 14.17; found: 1H NMR (CDCl3) 1.221–1.278 (m, 3H, CH3), 2.609–2.686 (s, 2H, CH2), 4.147 (s, 3H,
C, 51.60; H, 4.15; N, 14.23
CH3), 4.772–4.790 (m, 2H, CH2), 7.227 (s, 1H, Thiazole H), 7.411–7.441 (m, 2H, Ph
H),7.544 (bs, 1H, NH), 7.871 (d, J = 8.7 Hz, 2H, Ph H). GC–MS M? = 394, base peak:
223
9s
9t
Calcd: C, 59.63; H, 5.30; N, 16.36; found: 1H NMR (CDCl3) 2.258 (s, 3H, CH3), 3.876 (s, 3H, CH3), 4.117 (s, 3H, CH3), 4.690 (d, J
C, 59.59; H, 5.36; N, 16.43
= 5.7 Hz, 2H, CH2), 6.386 (s, 1 H, Pyrazole H), 6.964 (d, J = 8.7 Hz, 2H, Ph H), 7.262
(s, 1H, Thiazole H), 7.905 (d, J = 9.0 Hz, 2H, Ph H). GC–MS M?=342, base peak: 219
Calcd: C, 60.65; H, 5.66; N, 15.72; found: 1H NMR (CDCl3) 1.200 (t, J = 7.5 Hz, 3H, CH3), 2.587 (q, J = 7.6 Hz, 2H, CH2), 3.864
C, 60.71; H, 5.58; N, 15.70
(s, 3H, CH3), 4.124 (s, 3H, CH3), 4.672 (dd, J = 6.3, 2.1 Hz, 2H, CH2), 6.369 (s, 1H,
pyrazole H), 6.830 (bs, 1H, NH), 6.934–6.983 (m, 2H, Ph H), 7.126 (s, 1H, Thiazole
H), 7.841–7.890 (m, 2H, Ph H). GC–MS M? = 356, base peak: 219
9u
9v
Calcd: C, 55.31; H, 4.90; N, 14.33; found: 1H NMR (CDCl3) 1.222 (t, J = 7.5Hz, 3H, CH3), 2.609 (q, J = 7.5 Hz, 2H, CH2), 3.867
C, 55.36; H, 4.86; N, 14.41
(s, 3H, CH3), 4.148 (s, 3H, CH3), 4.751(dd, J = 5.7, 1.2 Hz, 2H, CH2), 6.946–6.986 (m,
2H, Ph H), 7.125 (s, 1H, Thiazole H), 7.550 (bs, 1H, NH), 7.859–7.899 (m, 2H, Ph H).
GC–MS M? = 390, base peak: 219
Calcd: C, 54.18; H, 4.55; N, 14.87; found: 1H NMR (CDCl3) 2.232 (s, 3H, CH3), 4.074 (s, 3H, CH3), 4.098 (s, 3H, CH3), 4.894 (d, J
C, 54.22; H, 4.49; N, 14.83
= 5.4 Hz, 2H, CH2), 7.065 (d, J = 8.4 Hz, 1H, Ph H), 7.159–7.242 (m, 1H, Ph H), 7.402
(s, 1H, Thiazole H), 7.485–7.609(m, 1H, Ph H), 8.052 (bs, 1H, NH), 8.707(s, 1H, Ph
H).HPLC-MS Pos [M?1]? = 445
Apparent structure–activity relationship
constant, the influence of Z moiety on improved activity
may be summarized as follows: Z-1 [ Z-4 & Z-5 [ Z-
In the general formula for compounds of 9 (Scheme 1),
structural optimization was carried out with four moieties:
the R1, R2, R3 and Z. On the basis of the bioassay data,
Variances substituents among R1, R2, R3 and Z showed a
significant relationship with both fungicidal activity against
E. graminis and insecticidal activity against A. fabae.
For fungicidal activity against E. graminis, when Z, R1
and R2 are kept invariant, the fungicidal activities of target
compounds are influenced by the R3 moiety. Conversion of
the R3 from a methyl group to other substituents with more
branched chain decreases the fungicidal activity. For
example, the fungicidal activity of 9e is better than that of
9f, while 9k and 9l, 9p and 9q, 9s and 9e correspond to a
similar law. This suggests that the increasing of alkyl chain
could be a weakening process for R3 of compounds.
Although the activity level of 9b is higher than that of 9a
abnormally, this law still possesses general significance. In
general, the activity order of R3 is CH3 [ CH2CH3 [ CH
(CH3)2 [ cyclopropyl. In addition, to keep R1, R2 and R3
2 [ Z-3. For example, fungicidal activities are correlated
as follows: 9b [ 9q & 9t [ 9l [ 9n.
For insecticidal activity against A. fabae, when Z, R1
and R2 are kept invariant, the influence of R3 moiety on the
insecticidal activities is different from that of fungicidal
activities. Modification of the R3 group from a methyl
group to an ethyl group increases the insecticidal activity.
For example, the insecticidal activities are correlated as
follows: 9b [ 9a, 9f [ 9e, 9l [ 9k, 9q [ 9p and 9t [ 9s.
Otherwise, to keep R1, R2 and R3 constant, the activity
order of Z is Z-2 [ Z-4 [ Z-5, while the regularity of other
Z substituents effected on activities is not obvious. For
example, insecticidal activities are correlated as follows:
9k [ 9p [ 9a and 9l [ 9q [ 9t.
On the basis of the above results, the superficial structure–
activity relationships were given. Although it is shallow, our
studies clearly show that these series of target compounds
should be worthwhile for further study as the lead compound
in the search for developing pesticides with high activities.
123

Chem. Pap.
Kim DS, Chun SJ, Jeon JJ (2004) Synthesis and fungicidal activity of
ethaboxam against Oomycetes. Pest Manag Sci 60:1007. doi:10.
1002/ps.873
Lahm GP, Stevenson TM, Selby TP (2007) A new insecticidal
anthranilic diamide that acts as a potent and selective ryanodine
receptor activator. Bioorg Med Chem Lett 17:6274–6279.
doi:10.1002/chin.200810138
Li ZM, Chen HS, Kai WG (1997) Synthesis and biological activity of
pyrazole derivatives. Chem Res Chin Univ 18:1794–1799.
doi:10.3321/j.issn:0251-0790.1997.11.009
Liu Q, Huang M, Liu A, Nie S, Lei M, Ren Y, Pei H, He L, Hu L, Hu
A (2014) Synthesis and herbicidal activity of novel N-Hetrocyclo
containing nitrogen methoxy-O-(4-aryloxy-phenyl) lactamide
Conclusions
In order to search for potent fungicidal and insecticidal
agents, a series of novel 1H-pyrazole-5–carboxamide
derivative containing thiazole rings were designed and
synthesized. Most of the compounds which we had syn-
thesized displayed excellent fungicidal and insecticidal
activity. Especially, compound 9l has LC50 values of
3.81 mg/L against A. fabae, and the insecticidal activity
level was comparable with the commercial insecticide,
Tolfenpyrad. Moreover, compound 9b has EC50 values of
3.04 mg/L against Erysiphe graminis, which are better than
those of the commercial fungicides, Thifluzamide and
Azoxystrobinare. The newly found structure–activity rela-
tionship may be helpful for further designing and devel-
oping novel 1H-pyrazole-5–carboxamide derivative as
fungicidal and insecticidal agents.
derivatives. Chin
cjoc201307017
J Org Chem 34:118–125. doi:10.6023/
Liu AP, Wang XG, Ou XM (2008) Synthesis and fungicidal activities
of novel bis(trifluoromethyl)phenyl-based strobilurins. J Agric
Food Chem 56:6562–6566. doi:10.1021/jf800651z
Mitsubishi Chemical (1995) Tebufenpyrad. J Pestic Sci 20:555–558.
doi:10.1584/jpestics.20.555
Mu¨ller N, Matzke M (2001) Method for preparing 1-alkyl-pyrazol-5-
carboxylic acid esters. EP, CN 1308612 A
Pazenok S, Lui N, Gerus I (2012) Method for producing 1-alkyl-/1-
aryl-5-prazole-carboxylic acid derivatites. Eur. Patent NO.
2513063 A1
Acknowledgements Research was performed under the National
Science Foundation of China (No. 21672057).
Pravin KS (2012) Synthesis and fungicidal activity of novel
3-(substituted/unsubstituted phenylselenonyl)-1-ribosyl/deoxyri-
bosyl-1H-1, 2, 4-triazole. J Agric Food Chem 60:5813–5818.
doi:10.1021/jf300730f
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