Synthesis and Insecticidal Evaluation of N-tert-Butyl-N'-thio[1-(6-chloro- 3-pyridylmethyl)-2-nitroiminoimidazolidine]-N,N'-diacylhydrazines

Article abstract of DOI:10.1021/jf903642s

A series of novel N-tert-butyl-N-thio[1-(6-chloro-3-pyridylmethyl)-2- nitroiminoimidazolidine]-N,N′-diacylhydrazines were synthesized by the reaction of chlorosulfenyl(N-tert-butyl-N,N′-diacylhydrazines) with 1-(6-chloro-3-pyridylmethyl)-2-nitroiminoimidazolidine (imidacloprid) in the presence of sodium hydride. Their larvicidal activities were evaluated. All of them exhibited insecticidal activities against Oriental armyworm and bean aphids. Toxicity assays indicated that at higher concentrations (200 mg L ^-1) the title compounds can kill aphids as fast as the parent imidacloprid in 2 h, whereas at lower concentration (10 mg L^-1), the title compounds can induce a premature, abnormal and lethal larval moult after 3 days of treatment, like the parent diacylhydrazines. 2009 American Chemical Society.

Full text of DOI:10.1021/jf903642s

1834 J. Agric. Food Chem. 2010, 58, 1834–1837
DOI:10.1021/jf903642s
Synthesis and Insecticidal Evaluation of N-tert-Butyl-N 0-thio[1-
(6-chloro-3-pyridylmethyl)-2-nitroiminoimidazolidine]-
N,N 0-diacylhydrazines
‡
,
J
IAN
S
HANG,*,† RANFEN
S
UN,‡ YONGQIANG
L
I
,‡ RUNQIU
,‡
H
UANG,‡ FUCHUN
B
I
AND
Q
INGMIN
W
ANG
*
†Chemistry and Biologic College, Yantai University, Yantai 264005, Shandong Province, People’s
Republic of China and ‡State Key Laboratory of Elemento-Organic Chemistry, Institute of
Elemento-Organic Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
A series of novel N-tert-butyl-N0-thio[1-(6-chloro-3-pyridylmethyl)-2-nitroiminoimidazolidine]-N,N0-dia-
cylhydrazines were synthesized by the reaction of chlorosulfenyl(N-tert-butyl-N,N0-diacylhydrazines)
with 1-(6-chloro-3-pyridylmethyl)-2-nitroiminoimidazolidine (imidacloprid) in the presence of sodium hyd-
ride. Their larvicidal activities were evaluated. All of them exhibited insecticidal activities against Oriental
armyworm and bean aphids. Toxicity assays indicated that at higher concentrations (200 mg L-1) the
title compounds can kill aphids as fast as the parent imidacloprid in 2 h, whereas at lower concentration
(10 mg L-1), the title compounds can induce a premature, abnormal and lethal larval moult after 3 days
of treatment, like the parent diacylhydrazines.
KEYWORDS: Synthesis; larvicidal activity; N-tert-butyl-N0-thio[1-(6-chloro-3-pyridylmethyl)-2-nitroimino-
imidazolidine]-N,N0-diacylhydrazines; diacylhydrazines; imidacloprid
INTRODUCTION
nylated derivatives of diacylhydrazines and found that these
compounds exhibit excellent larvicidal activity (11, 12). Encour-
agedbythe reports, we developed the idea that the introductionof
imidacloprid into N-tert-butyl-N,N0-diacylhydrazine would re-
tain the good insecticidal activity of the parent imidacloprid and
N-tert-butyl-N,N0-diacylhydrazine. Therefore, in a search for new
insecticides with improved biological properties and different
activity spectrum, we designed and synthesized a series of N-tert-
butyl-N0-thio[1-(6-chloro-3-pyridylmethyl)-2-nitroiminoimidazo-
lidine]-N,N0-diacylhydrazines of the general structure 4 as shown
in Scheme 2. This article is concerned with the synthesis and
biological activity of these compounds.
N-tert-Butyl-N,N0-diacylhydrazines as a new class of insect
growth regulators have been found to mimic the action of
20-hydroxyecdysone to activate the ecdysone receptor, leading
to lethal premature moulting (1-3). Among nonsteroidal ecdy-
sone agonists, N-tert-butyl-N0-(4-ethylbenzoyl)-N-3,5-dimethyl-
benzoylhydrazine (RH-5992) has been the first to be commer-
cialized as a lepidopteran-specific insecticide, with a low toxicity
profile toward mammals, birds, and fishes, as well as toward
nontarget arthropods such as insect pollinators, predators, and
parasitoids (4). At present, another three new structural analo-
gues, methloxyfenozide (RH-2485), halofenozide (RH-0345),
and chromafenozide (ANS-118), have already been brought to
the market (5, 6). Neonicotinoids are among the most effective
insecticides for the control of sucking insect pests such as aphids,
whiteflies, leaf- and planthoppers, thrips, and a number of
coleopteran pests. Their broad insecticidal spectra, together with
good systemic properties and low mammalian toxicity, make the
neonicotinoids the most rapidly expanding insecticidal class since
the launch of the first compound, imidacloprid, by Bayer
CropScience in 1991 (7, 8).
MATERIALS AND METHODS
Synthetic Procedures. All reactions were carried out under a nitrogen
atmosphere with the exclusion of moisture. Proton NMR spectra were
obtained at 300 MHz using a Bruker AV300 spectrometer. Chemical shift
values (δ) are given in ppm and are downfield from internal tetramethyl-
silane. Elemental analyses were determined on an MT-3 elemental
analyzer. Melting points were taken on a Thomas-Hoover melting point
apparatus and were uncorrected. Column chromatographic purification
was carried out by using silica gel.
It has been reported that biscarbamoyl sulfide derivatives of
methylcarbamate insecticides retained the good insecticidal ac-
tivity of the parent methylcarbamate but were substantially less
toxic to the white mouse (9, 10). In the previous papers from our
laboratory, we described the synthesis of two series of N-sulfe-
General Synthetic Procedure for Chlorosulfenyl(1-tert-butyl-1,2-
diacylhydrazine) (2). To a stirred solution of sulfur dichloride (0.008
mol) and dichloromethane (15 mL) was added a solution of pyridine
(0.008 mol) in dichloromethane (5 mL) dropwise at -10 °C. Then a
solution of 1-tert-butyl-1,2-diacylhydrazine (0.007 mol) (1) in dichloro-
methane (5 mL) was added at -10 °C. The mixture was stirred at room
temperature for 4 h. Then the reaction mixture was concentrated under
reduced pressure and added hexane (10 mL). The mixture was filtered to
give a yellow liquid. It was used for further operations without purification
as shown in Scheme 1.
*To whom correspondence should be addressed. (J.S.) Tel: þ86(0)535-
6902700. Fax: þ86(0)535-6902078. E-mail: shangjian.@126.com. (Q.W.)
Tel: þ86(0)22-23499842. Fax: þ86(0)22-23499842. E-mail: wang98h@
263.net; wangqm@nankai.edu.cn.
pubs.acs.org/JAFC
Published on Web 12/30/2009
© 2009 American Chemical Society

Article
J. Agric. Food Chem., Vol. 58, No. 3, 2010 1835
Table 1. Physical Properties of Compounds 4a-k
Scheme 1. General Synthetic Route for Chlorosulfenyl(N-tert-butyl-N,N 0-
diacylhydrazines) (2)
compd
X
Y
mp (°C)
yield (%)
states
4a
4b
4c
4d
4e
4f
H
H
4-Et
163-165
173-175
31.5
60.5
11.7
10.0
62.2
38.1
22.2
23.0
38.1
46.8
57.1
colorless crystal
colorless crystal
colorless semisolid
colorless semisolid
colorless crystal
colorless crystal
colorless semisolid
colorless crystal
colorless crystal
colorless crystal
colorless crystal
3,5-Me2
3,5-Me2
3,5-Me2
4-Cl
H
3,5-Me2
H
177-179
180-182
4-OMe
2-Cl
3-Cl
H
4g
4h
4i
H
H
175-177
187-189
198-120
125-127
2-OMe
2-OMe
4-OMe
H
4j
2-OMe
4-OMe
4k
Scheme 2. General Synthetic Route for the Title Compounds 4a-4k
Table 2. Larvicidal Activities of Products 4a-k and Their Parent Compounds
1a-k and 3 against Oriental Armyworma
larvicidal activities (mg L-1
)
compd
500
100
200
80
100
0
50
25
10
5
4a
1a
4b
1b
4c
1c
4d
1d
4e
1e
4f
100
100
70
100
0
90
100
70
70
95
85
70
80
55
50
70
20
50
10
100
25
95
40
100
0
0
60
10
70
0
10
0
100
100
10
100
25
0
0
0
General Synthetic Procedure for N-tert-Butyl-N0-thio[1-(6-chloro-
3-pyridylmethyl)-2-nitroiminoimidazolidine]-N,N0-diacylhydrazines
(4a-k). To a stirred admixture of 1-(6-chloro-3-pyridylmethyl)-2-nitro-
iminoimidazolidine (imidacloprid) (0.006 mol) (3) in anhydrous xylene
(40 mL) was added sodium hydride (0.007 mol) over a period of 5 min.
The mixture was stirred at boiling temperature for 2 h and then cooled
to -10 °C. Then the crude chlorosulfenyl(1-tert-butyl-1,2-diacylhydra-
zine) (2) solution was added dropwise. After the addition was complete,
the reaction mixture was stirred for 6 h at room temperature. The solid was
then filtered off, and the filtrate was concentrated under vacuum. Then
the residue was purified by column chromatography on silica gel using
petroleum ether (60-90 °C), dichloromethane, and ethyl acetate (20:1:1 by
volume) as the eluent. N-tert-Butyl-N0-thio[1-(6-chloro-3-pyridylmethyl)-
2-nitroiminoimidazolidine]-N,N0-diacylhydrazines (4a-k) was obtained
as shown in Scheme 2. The physical properties of compounds 4a-k are
listed in Table 1.
80
70
0
1f
60
100
4g
1g
4h
1h
4i
60
30
100
25
95
0
10
90
0
0
75
100
90
80
40
70
100
20
45
0
1i
100
10
90
0
10
4j
80
70
0
40
1j
10
4k
1k
3
100
95
70
40
100
40
10
60
0
0
30
20
10
a 1a, RH-5849; 1b, RH-5992; 3, imidacloprid.
Data for 4a. 1H NMR (CDCl3, ppm): δ1.36 (br s, 9H, C(CH3)3), 3.32
(br d, 2H, CH2), 3.71 (br s, 2H, CH2), 4.16 (m, 1H, CH2), 4.72 (m, 1H,
CH2), 6.64-8.14 (m, 13H, ArH). Anal. Found: C, 55.78; H, 4.87; N, 16.76.
Calcd. for C27H28ClN7O4S: C, 55.71; H, 4.85; N, 16.84.
Data for 4b. 1H NMR(CDCl3): δ1.25-1.33 (m, 12H, C(CH3)3þCH2-
CH3), 2.37 (s, 6H, ArCH3), 2.71 (m, 2H, CH2), 3.33 (br d, 2H, CH2), 3.75
(br s, 2H, CH2), 4.17 (br s, 1H, CH2), 4.68 (br s, 1H, CH2), 6.59-8.12
(m, 10H, ArH). Anal. Found: C, 58.35; H, 5.60; N, 15.30. Calcd. for
C31H36ClN7O4S: C, 58.34; H, 5.69; N, 15.36.
Data for 4c. 1H NMR(CDCl3): δ1.35 (br s, 9H, C(CH3)3), 2.37 (s, 6H,
ArCH3), 3.32 (br d, 2H, CH2), 3.73 (br s, 2H, CH2), 4.17 (m, 1H, CH2),
4.69 (m, 1H, CH2), 6.59-8.31 (m, 11H, ArH). Anal. Found: C, 57.18; H,
5.28; N, 15.93. Calcd. for C29H32ClN7O4S: C, 57.09; H, 5.29; N, 16.07.
Data for 4d. 1H NMR(CDCl3): δ1.34 (br s, 9H, C(CH3)3), 2.35 (s, 12H,
ArCH3), 3.33 (br d, 2H, CH2), 3.77 (br s, 2H, CH2), 4.15 (m, 1H, CH2),
4.70 (m, 1H, CH2), 6.58-8.12 (m, 9H, ArH). Anal. Found: C, 58.20; H,
5.80; N, 15.20. Calcd. for C31H36ClN7O4S: C, 58.34; H, 5.69; N, 15.36.
Data for 4e. 1H NMR(CDCl3): δ1.34 (br s, 9H, C(CH3)3), 3.32 (br d,
2H, CH2), 3.70 (br s, 2H, CH2), 4.24 (br d, 1H, CH2), 4.61 (br s, 1H, CH2),
6.78-8.15 (m, 12H, ArH). Anal. Found: C, 52.41; H, 4.36; N, 15.71.
Calcd. for C27H27Cl2N7O4S: C, 52.60; H, 4.41; N, 15.90.
4.70 (br d, 1H, CH2), 6.70-8.12 (m, 12H, ArH). Anal. Found: C, 54.94; H,
4.89; N, 16.11. Calcd. for C28H30ClN7O5S: C, 54.94; H, 4.94; N, 16.02.
Data for 4g. 1H NMR(CDCl3): δ1.37 (br s, 9H, C(CH3)3), 3.35 (br d,
2H, CH2), 3.82 (br s, 2H, CH2), 4.14 (br d, 1H, CH2), 4.72 (br s, 1H, CH2),
6.59-8.10 (m, 12H, ArH). Anal. Found: C, 52.72; H, 4.39; N, 16.05.
Calcd. for C27H27Cl2N7O4S: C, 52.60; H, 4.41; N, 15.90.
Data for 4h. 1H NMR(CDCl3): δ1.35 (br s, 9H, C(CH3)3), 3.36 (br d,
2H, CH2), 3.70 (br s, 2H, CH2), 4.22 (br d, 1H, CH2), 4.63 (br s, 1H, CH2),
6.77-8.15 (m, 12H, ArH). Anal. Found: C, 52.78; H, 4.67; N, 15.68.
Calcd. for C27H27Cl2N7O4S: C, 52.60; H, 4.41; N, 15.90.
Data for 4i. 1H NMR(CDCl3): δ1.35 (br s, 9H, C(CH3)3), 3.35 (br d,
2H, CH2), 3.80 (br s, 2H, CH2), 3.94 (s, 3H, OCH3), 4.07 (br d, 1H, CH2),
4.79 (br d, 1H, CH2), 6.45-8.17 (m, 12H, ArH). Anal. Found: C, 54.92; H,
4.90; N, 15.95. Calcd. for C28H30ClN7O5S: C, 54.94; H, 4.94; N, 16.02.
Data for 4j. 1H NMR(CDCl3): δ1.34 (br s, 9H, C(CH3)3), 3.27 (br d,
2H, CH2), 3.81 (br s, 2H, CH2), 3.88 (s, 3H, OCH3), 3.92 (s, 3H, OCH3),
4.18 (br d, 1H, CH2), 4.74 (br d, 1H, CH2), 6.59-8.19 (m, 11H, ArH).
Anal. Found: C, 54.16; H, 5.29; N, 15.38. Calcd. for C29H32ClN7O6S: C,
54.24; H, 5.02; N, 15.27.
Data for 4k. 1H NMR(CDCl3): δ1.31 (br s, 9H, C(CH3)3), 3.35 (br d,
2H, CH2), 3.68 (br s, 2H, CH2), 3.86 (s, 6H, OCH3), 4.13 (m, 1H, CH2),
4.69 (m, 1H, CH2), 6.69-8.11 (m, 11H, ArH). Anal. Found: C, 54.12; H,
4.96; N, 15.28. Calcd. for C29H32ClN7O6S: C, 54.24; H, 5.02; N, 15.27.
Data for 4f. 1H NMR(CDCl3): δ1.35 (br s, 9H, C(CH3)3), 3.33 (br d,
2H, CH2), 3.68 (br s, 2H, CH2), 3.86 (s, 3H, OCH3), 4.17 (br d, 1H, CH2),

1836 J. Agric. Food Chem., Vol. 58, No. 3, 2010
Shang et al.
Biological Assay. Insecticidal Activity against Oriental Armyworm
(Mythimna separata). The larvicidal activities of the title compounds
(4a-k) against the Oriental armyworm were evaluated and compared
with those of the parent compounds 1a-k and 3 using a previously
reported procedure (13, 14). The larvicidal activity was tested against
the Oriental armyworm [Mythimna (= Pseudaletia) separata (Walker)] by
foliar application. For the foliar armyworm tests, individual corn leaves
were placed on moistened pieces of filter paper in Petri dishes. The leaves
were thensprayed with the test solution andallowedto dry. Thedishes were
infested with 10 fourth-instar armyworm larvae. Percentage mortalities
were evaluated after 4 days of treatment. Evaluations are based on a
percentage scale of 0-100 in which 0 = no activity and 100 = total killed.
The larvicidal activity is summarized in Table 2.
in excellent yields by the reaction of sulfur dichloride with 1-tert-
butyl-1,2-diacylhydrazine (1) in dichloromethane using pyridine as
the acid acceptor as shown in Scheme 1. Chlorosulfenyl(1-tert-
butyl-1,2-diacylhydrazine) (2) without further purification was
reacted with 1-(6-chloro-3-pyridylmethyl)-2-nitroiminoimidazoli-
dine (imidacloprid) (3) to give products 4.
Structure. As the 1H NMR of 4 cannot be used to verify
N-CH2-, they generally have bread or multiple formants. We
determined its structure using the X-ray crystallography data.
The results demonstrate that compound 4g has the desired
structure despite the fact that the 1H NMR not having the
ordinary formant of N-CH2-. The molecular structure of
compound 4g was reported (16) as shown in Figure 1.
Insecticidal Activity against Bean Aphids (Aphis fabae Scopoli). The
insecticidal activities of the title compound (4a-k), the parent compounds
1a-k, and 3 against bean aphids were evaluated using a previously
reported procedure (15). Bean aphids were dipped according to a slightly
modified FAO dip test. The tender shoots of soybean with 40-60 healthy
apterous adult aphids were dipped in the diluted solutions of the
compounds for 5 s and the superfluous fluid removed and placed in
a conditioned room. Mortality was calculated 48 h after treatment.
Each treatment was performed three times. The revised death rate was
calculated by the Abbott formula. The insecticidal activity is summarized
in Table 3.
Bioassay. We combined the bioactive units of diacylhydrazine
(1) and imidacloprid (3) to design and synthesize novel com-
pounds 4a-k. The results of insecticidal activities given in
Tables 2 and 3 showed that the title compounds 4a-k exhibit
insecticidal activities against the Oriental armyworm and bean
aphids. Compound 4b exhibited 90% larvicidal activity at 10 mg
L
-1, which is parallel to its corresponding parent 1b (RH-5992).
Compounds 4f and 4j displayed higher larvicidal activities against
the Oriental armyworm than their corresponding parents 1f and
1j, which suggested that introduction of imidacloprid into N-tert-
butyl-N,N0-diacylhydrazine through nirogen-sulfur-nitrogen
bond formation had a positive effect on larvicidal activities.
These derivatives have increased dissolvability relative to the
parents 1 and are soluble in most organic solvents. The mode of
action of the title compounds 4a-k is very interesting. Toxicity
assays indicated that at higher concentrations (200 mg L-1) the
title compounds can kill aphids as fast as the parent compounds 3
in 2 h, whereas at lower concentration (10 mg L-1), the title
compounds can induce a premature, abnormal, and lethal larval
moult after 3 days of treatment, like the parent compounds 1.
In summary, a series of novel N-tert-butyl-N0-thio[1-(6-chloro-
3-pyridylmethyl)-2-nitroiminoimidazolidine]-N,N0-diacylhydra-
zines were synthesized by the reaction of chlorosulfenyl(N-tert-
butyl-N,N0-diacylhydrazines) with imidacloprid in the presence
of sodium hydride. These derivatives have increased dissolva-
bility relative to the parents 1 and are soluble in most organic
RESULTS AND DISCUSSION
Synthesis. The title compounds were prepared by the reaction
of chlorosulfenyl(1-tert-butyl-1,2-diacylhydrazine) (2) with 1-(6-
chloro-3-pyridylmethyl)-2-nitroiminoimidazolidine (imidacloprid)
(3) in the presence of sodium hydride as shown in Scheme 2.
Chlorosulfenyl(1-tert-butyl-1,2-diacylhydrazine) (2) was prepared
Table 3. Insecticidal Activities against Bean Aphids (200 mg L-1 a
compd 4a 4b 4c 4d 4e 4f 4g 4h 4i
)
4j 4k
death rate % 100 53 80 89 87 95 84 86 92 91 87
compd
1a 1b 1c 1d 1e 1f 1g 1h
1i
1j 1k
22
death rate%
0
0
12 10 26 0 18 12 32
0
a The death rate of imidacloprid is 100% at 200 mg L-1
.
Figure 1. Molecular structure of the title compound 4g.

Article
J. Agric. Food Chem., Vol. 58, No. 3, 2010 1837
solvents. All of them exhibited insecticidal activities against the
Oriental armyworm and bean aphids. Interestingly, toxicity
assays indicated that these products have both insecticidal
activities as fast as imidacloprid at higher concentration and
insect growth regulators’ activities like those of diacylhydrazines
at lower concentrations. The results are promising, and further
studies on insecticidal activities and systemic activities of the title
compounds are underway and will be reported in due course.
ment of nitromethylene with nitroconjugated system. J. Agric. Food
Chem. 2009, 57, 951–957.
(9) Drabek, J. Bis-(O-1-alkylthio-ethylimino)-N-methyl-carbamic acid)-
N,N0-sulphide insecticides. U.S. Patent 4,004,031, 1977.
(10) Fahmy, M. A. H.; Chiu, Y. C.; Fukuto, T. R. Selective toxicity of
N-substituted biscarbamoyl sulfides. J. Agric. Food Chem. 1974, 22,
59–62.
(11) Wang, Q. M.; Huang, R. Q.; Bi, F. C.; Li, Z. G. Synthesis and bio-
logical activity of novel N-sulfenylated derivatives of diacylhydra-
zines. J. Chem. Res. 2001, 342–343.
(12) Wang, Q. M.; Cheng, J. R.; Huang, R. Q. Synthesis and insecticidal
evaluation of novel N-(S-amino)sulfenylated derivatives of diacyl-
hydrazines. Pest Manag. Sci. 2002, 58, 1250–1253.
LITERATURE CITED
(1) Wing, K. D. RH5849, a nonsteroidal ecdysone agonist: Effects on a
Drosophila cell line. Science 1988, 241, 467–469.
(2) Wing, K. D.; Slawecki, R. A.; Carlson, G. R. RH5849, a nonster-
oidal ecdysone agonist: Effects on larval Lepidoptera. Science 1988,
241, 470–472.
(3) Wing, K. D. Anthelmintic N0-substituted-N,N0-disubstituted-hydra-
(13) Hsu, A. C.; Aller, H. E. Insecticidal N0-substituted-N,N0-disubsti-
tuted-hydrazines. U.S. Patent 5,117,057, 1993.
(14) Mao, C. H.; Wang, Q. M.; Huang, R. Q.; Bi, F. C.; Chen, L.; Liu,
Y. X.; Shang, J. Synthesis and insecticidal evaluation of novel N-
oxalyl derivatives of Tebufenozide. J. Agric. Food Chem. 2004, 52,
6737–6741.
(15) Zhao, Y.; Li, Y. Q.; Ou, X. M.; Zhang, P. X.; Wang, Q. M. Synthesis,
insecticidal, and acaricidal activities of novel 2-aryl-pyrrole deriva-
tives containing ester groups. J. Agric. Food Chem. 2008, 56, 10176–
10182.
(16) Shang, J.; Wang, Q. M.; Huang, R. Q.; Chen, L.; Gao, J. H. N0-
Benzoyl-N-tert-butyl-2-chloro-N0-{[3-(6-chloro-3-pyridylmethyl)-2-
nitriminoimidazolidin-1-yl]sulfanyl}-benzohydrazide. Acta Crystal-
logr., Sect. E 2009, 65, o2131–o2132.
zines. U.S. Patent 5,424,333, 1995.
(4) Dhadialla, T. S.; Jansson, R. K. Non-steroldal ecdysone agonists:
New tools for IPM and insect resistance management. Pestic. Sci.
1999, 55, 357–359.
(5) Carlson, G. R.; Dhadialla, T. S.; Hunter, R. The chemical and
biological properties of methoxyfenozide, a new insecticidal ecdys-
teroid agonist. Pest Mang. Sci. 2001, 57, 115–119.
(6) Hsu, A. C. T. 1,2-Diacyl-1-alkylhydrazines, a New Class of Insect
Growth Regulators. In Synthesis and Chemistry of Agrochemical II;
Baker, B. R., Fenyes, J. G., Moberg, W. K., Eds.; ACS Symposium Series
443, American Chemical Society: Washington, DC, 1991; pp 478-490.
(7) Elbert, A.; Hass, M.; Springer, B.; Thielert, W.; Nauen, R. Applied
aspects of neonicotinoid uses in crop protection. Pest Manag. Sci.
2008, 64, 1099–1105.
Received for review October 17, 2009. Revised manuscript received
December 16, 2009. Accepted December 17, 2009. We gratefully
acknowledge the support of this work by the National Key Project for
Basic Research (2010CB126106) and the National Natural Science
Foundation of China (20672064).
(8) Shao, X. S; Li, Z.; Qian, X. H.; Xu, X. Y. Design, synthesis, and
insecticidal activities of novel analogues of neonicotinoids: replace-