Novel (E)-β-farnesene analogues containing 2-nitroiminohexahydro-1,3,5-triazine: Synthesis and biological activity evaluation

Article abstract of DOI:10.3390/molecules21070825

In order to discover novel eco-friendly compounds with good activity for aphid control, (E)-β-farnesene (EβF), the main component of the aphid alarm pheromone, was chosen as the lead compound. By introducing a 2-nitroimino-hexahydro-1,3,5-triazine moiety (abbreviated NHT) to replace the unstable conjugated double bond system of EβF, a series of novel EβF analogues containing the NHT moiety were synthesized via the reaction of substituted NHT rings with (E)-1-chloro-3,7-dimethylocta-2,6-diene. All the compounds were characterized by ¹H-NMR, ¹³C-NMR, IR, and high resolution mass spectroscopy (HRMS). The bioassay results showed that all the analogues displayed different repellent and aphicidal activities against green peach aphid (Myzus persicae). Particularly, the analogue 4r exhibited obvious repellent activity (repellent proportion: 78.43%) and similar aphicidal activity against M. persicae (mortality: 82.05%) as the commercial compound pymetrozine (80.07%). A preliminary structure-activity relationship (SAR) study was also performed, which offered valuable clues for the design of further new EβF analogues.

Full text of DOI:10.3390/molecules21070825

molecules
Article
Novel (E)-β-Farnesene Analogues Containing
2-Nitroiminohexahydro-1,3,5-triazine: Synthesis
and Biological Activity Evaluation
Yaoguo Qin 1, Jingpeng Zhang 1, Dunlun Song 2, Hongxia Duan 1, Wenhao Li 1
and Xinling Yang 1,
*
1
Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China;
qyg@cau.edu.cn (Y.Q.); jpzhang@cau.edu.cn (J.Z.); hxduan@cau.edu.cn (H.D.); oliverlwh@cau.edu.cn (W.L.)
Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193,
China; songdl@cau.edu.cn
2
*
Correspondence: yangxl@cau.edu.cn; Tel.: +86-10-6273-2223
Academic Editor: Wei-Zhu Zhong
Received: 15 March 2016; Accepted: 20 June 2016; Published: 24 June 2016
Abstract: In order to discover novel eco-friendly compounds with good activity for aphid control,
(E)-
lead compound. By introducing a 2-nitroimino-hexahydro-1,3,5-triazine moiety (abbreviated
NHT) to replace the unstable conjugated double bond system of E F, a series of novel EβF
β-farnesene (EβF), the main component of the aphid alarm pheromone, was chosen as the
β
analogues containing the NHT moiety were synthesized via the reaction of substituted NHT rings
with (E)-1-chloro-3,7-dimethylocta-2,6-diene. All the compounds were characterized by 1H-NMR,
13C-NMR, IR, and high resolution mass spectroscopy (HRMS). The bioassay results showed that all
the analogues displayed different repellent and aphicidal activities against green peach aphid (Myzus
persicae). Particularly, the analogue 4r exhibited obvious repellent activity (repellent proportion:
78.43%) and similar aphicidal activity against M. persicae (mortality: 82.05%) as the commercial
compound pymetrozine (80.07%). A preliminary structure-activity relationship (SAR) study was also
performed, which offered valuable clues for the design of further new EβF analogues.
Keywords: (E)-β-farnesene analogues; 2-nitroiminohexahydro-1,3,5-triazine; synthesis; bioactivity;
structure-activity relationship
1. Introduction
As some of the major pests in agriculture, aphids cause considerable damage [1,2] to crop growth,
yield and quality by sucking phloem sap [
3
], secreting honeydew to induce frequently plant sooty
]. Owing to the variety of species, large population,
moulds [ ] and transmitting plant viruses [5–7
1,
2,
4
fast reproduction and high resistance to chemical insecticides, aphid control has become more and
more challenging. As the idea of eco-friendly pest control is increasingly recognized worldwide, the
strategy for aphid control has changed from traditional “killing” to rational “regulation” [8]. In the
past decades, traditional aphid control methods have largely relied on agrochemicals, which has led to
increasing pest resistance and cross resistance. Therefore, it is important to develop novel aphid control
strategies. Using aphid alarm pheromones could be an alternative way to control their population by
manipulating aphid behaviors, and is also regarded to be conducive to ecological protection [9,10].
Aphid alarm pheromone is a strong and efficient pheromone produced and utilized by most
aphid species [11
(E)-7,11-dimethyl-3-methylenedodeca-1,6,10-triene, Scheme 1), which possesses multiple biological
functions. Besides its alarm activity, E F also showed insecticidal activity at high doses [15], and
could be used as the synergistic agent when mixed with commercial insecticides to control aphids [16].
–14]. The main component of aphid alarm pheromone is (E)-β-farnesene (EβF,
β
Molecules 2016, 21, 825; doi:10.3390/molecules21070825
www.mdpi.com/journal/molecules

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However, it is difficult to use in the field because of its instability due to the presence of a conjugated
double bond system. Therefore, it is necessary to develop novel E
aphid management.
βF analogues with good stability for
NNO2
NH
NNO2
NH
HN
N
N
R
N
R
Analogues 4
Lead compound
β
(E)- -f arnesene
Scheme 1. The design strategy of EβF analogues 4.
With the advantages of multiple bioactivities, heterocycles, such as triazine, pyrazole, pyridine,
oxadiazine and triazole, play important roles in the development of the agrochemical and medical
fields [17]. Among them, the 2-nitroiminohexahydro-1,3,5-triazine (NHT) system, with its simple
structure and low cost, is a very important active group in the agrochemically active molecule field.
Compounds containing NHT have been discovered to possess a wide range of insecticidal properties,
such as inhibiting population growth of Aphis gossypii [18], Myzus persicae [19], Nephotettix cincticeps [20],
Ctenocephalides felies [21], Aphis medicagini [22], Spodoptera littoralis [23], and Nilaparvata lugens [24].
Introducing active groups is an effective method to develop new eco-friendly agrochemicals. As
mentioned above, 2-nitroiminohexahydro-1,3,5-triazine is a very important and active group widely
existing in agrochemicals, especially in insecticides. In order to develop alarm pheromone analogues
with good activity and high stability for eco-friendly aphid management, herein a series of E
analogues were designed and synthesized by newly introducing an effective group, NHT, to replace
the conjugated double bonds of E F. The design strategy of these E F analogues is shown in Scheme 1.
βF
β
β
Their biological activities, including repellent activity as well as aphicidal activity, were investigated.
Their structure-activity relationships were also studied to provide some useful clues for the further
design and development of novel EβF analogues.
2. Results and Discussion
2.1. Chemistry
The synthetic route for the intermediates and E
intermediate (geranyl chloride) was obtained from geraniol (
a nucleophilic substitution reaction using pyridine as an acid-binding agent. According to the reported
method [25], the key 5-substituted-1,3,5-triazine-2-N-nitrate amine intermediates were prepared
by Mannich reactions between nitroguanidine, formaldehyde and different commercially available
βF analogues is illustrated in Scheme 2. The
2
1) and phosphorus trichloride (PCl3) via
3
primary amines in a one-pot method using a protic solvent. Under moderate conditions, the E
analogues were synthesized through the nucleophilic substitution reaction between intermediates
and 3a 3t in acetonitrile using K2CO3 as acid acceptor to produce the corresponding E
4a–4t. The synthetic procedure is described in Section 3.2.3.
The structures of all synthesized E F analogues 4a
4t were confirmed by IR, 1H-NMR, 13C-NMR
βF
4
2
–
βF analogues
β
–
and HR-ESI-MS. Their physical and chemical properties and structure characterization were described
in Section 3.2.3. In the IR spectra, the analogues showed strong absorptions around 3300 cm´1 due
to the N-H stretching vibration. Strong bands at about 1600 cm´1 were detected because of the C=C
´1
stretching vibration. The extremely strong absorption bands detected around 1550 and 1370 cm are
due to the nitro groups.

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Scheme 2. Synthetic route to the EβF analogues 4a–4t.
1
In the H-NMR spectrum of E
βF analogues 4a
–
4t, a wide single peak in the
δ
9.48–9.75 ppm
chemical shift range was due to the presence of NH protons. The protons of two double bonds were
observed at 5.10–5.22 ppm in compounds 4a 4i and 4k 4l while the signals shifted upfield to about
4.94–5.07 ppm in analogues 4j and 4m 4t. The signals of the C-H protons in NHT were clearly
4.33–4.97 ppm. The protons of the methylene connected to the triazine group were split
δ
–
–
δ
–
observed at
δ
into a doublet in the range from 3.94 to 4.12 ppm with a coupling constant of 6.83–7.27 Hz attributed
to the long range coupling with the proton on the adjacent carbon atom.
The structure of the analogue 4r was further confirmed by single crystal X-ray analysis. Its
molecule crystal structure had been deposited with the Cambridge Crystallographic Data Centre, under
deposition number CCDC 1437627. A perspective view of the compound is shown in Figure 1 and
the crystal data are presented in Table 1. Crystal Data for 4r (C19H26ClN5O2, M = 391.90): monoclinic,
space group P21/c (No. 14), a = 5.8324(11) Å, b = 38.200(5) Å, c = 9.1298(13) Å,
V = 2028.7(5) Å3, Z = 4, T = 180.01(10) K, ) = 0.212 mm´1, Dcalc = 1.283 g/mm3, 8970
(Mo K
reflections measured (6.182
Θ ď 52.044), 3971 unique (Rint = 0.1078) which were used in all
calculations. The final R1 was 0.0893 (I > 2 (I)) and wR2 was 0.2328. More data of this crystal structure,
such as the crystal data and structure refinement, crystal packing, fractional atomic coordinates (
104)
and equivalent isotropic displacement parameters (Å2 103), bond length and bond angle of the
analogue 4r are presented in the Supplementary Materials.
β
= 94.170(15)˝,
µ
α
ď
2
σ
ˆ
ˆ
Figure 1. The crystal structure of the analogue 4r.

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Table 1. Crystal data and structure refinement for 4r.
Compound
4r
Empirical formula
Formula weight
Temperature/K
Crystal system
Space group
a/Å
C10H13N5O3
251.25
180.15
monoclinic
P21/c
15.4268(13)
5.3261(4)
b/Å
14.6589(11)
c/Å
α/˝
90
β/˝
110.045(9)
γ/˝
90
Volume/Å3
Z
1131.48(16)
4
ρ calc mg/mm3
m/mm´1
F(000)
1.475
0.113
528.0
Crystal size/mm3
0.2 ˆ 0.1 ˆ 0.1
2Θ range for data collection
Index ranges
7.372˝ to 50.036˝
´15 ď h ď 16, ´6 ď k ď 3, ´14 ď l ď 17
2423
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
Final R indexes (I ě 2σ (I))
Final R indexes [all data]
Largest diff. peak/hole/e Å´3
CCDC No.
1780[R(int) = 0.0173]
1780/0/164
1.086
R1 = 0.0371, wR2 = 0.0914
R1 = 0.0480, wR2 = 0.0996
0.16/´0.22
1437627
In particular, the stability of 4r and EβF was detected by high performance liquid chromatography
(HPLC) after leaving them at room temperature and exposing them to air for periods up to 48 h. On
such conditions, no degradation of the analogue 4r could be detected. The E F degraded from 92.5% to
β
an undetected level, which was in good agreement with the reported degradation rate (94%) of EβF [26].
These results suggested that 4r was more stable than EβF.
2.2. Biological Activity
2.2.1. Repellent Activity
As one of the major aphid pests in agriculture, Myzus persicae was chosen to test the repellent
activity with a two-way olfactometer as described in Section 3.5.1. In order to determine if an E
βF
analogue had repellent effect, the numbers of aphids in the control and treatment arms was compared
statistically with SPSS Statistics version 21 (IBM, Armonk, NY, USA) by paired t-test. Firstly, the
behavioral response of apterous adult Myzus persicae to the solvent n-hexane was tested, in which
aphids always showed no preference for either arm. Then, the repellent effect of these E
was measured using E F as positive control. All there E F analogues exhibited significant repellent
differences against M. persicae between the mean number of aphids in control arm and those in
treatment arm (Figure 2). The different E F analogues differed in their repellent activities (Table 2).
Even though some compounds displayed a fairly high repellent activity (up to 80.07% of aphids
were repelled), all tested E F analogues repelled fewer aphids than E F itself. Generally, the E
βF analogues
β
β
β
β
β
βF
analogues where R was a substituted aromatic ring had a higher repellent activity than those with alkyl
R groups. When R was alkyl, chain length (number of C < 4) had a positive effect on repellent activity
(
4a
<
4b
<
4c
<
4d). However, the number of chain branches seemed to have no effect on repellent
4d « 4g « 4h). In addition, these analogues exhibited similar activity whether the
activity (4c « 4f
,

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R group was a benzyl ring or a phenyl ring (4j « 4k). A preliminary structure-activity relationship
analysis discovered that the analogues with R was a substituted phenyl ring presented higher activity
than when R was an unsubstituted phenyl ring. Substituent in the ortho-position of the phenyl were
more beneficial for activity compared with meta- and para-substituents (4i
> 4j, 4i > 4k). In the same
substituent position on the phenyl ring, the electron-withdrawing substituents contributed to better
repellent activity than that of electron-donating groups (4q, 4r > 4o, 4p and 4s).
Figure 2. Behavioral response of M. persicae to EβF analogues 4a–4t. The number of aphids
(mean standard deviation) in both arms were counted and analyzed by paired t-test. “ns” represents
˘
no significance; “*” represents significant difference at p
difference at p ď 0.01 level.
ď
0.05 level; and “**” represents significant
Table 2. Repellent proportion (RP) of the EβF analogues 4a–4t against M. persicae.
Compd.
R
RP (%) a
Compd.
R
RP (%) a
67.56 ˘ 2.77 f,g
75.62 ˘ 2.16 h
67.28 ˘ 1.66 f
69.47 ˘ 1.91 g
67.79 ˘ 1.81 f,g
74.11 ˘ 2.74 h
78.43 ˘ 2.00 i
67.89 ˘ 2.24 f,g
80.07 ˘ 2.20 i
96.47 ˘ 2.31 j
4a
4b
4c
4d
4e
4f
4g
4h
4i
CH3
CH2CH3
52.28 ˘ 2.40 a
56.74 ˘ 1.37 b
60.89 ˘ 1.41 c
64.03 ˘ 1.40 e
55.96 ˘ 1.54 b
61.34 ˘ 1.42 c
63.89 ˘ 1.42 d,e
62.89 ˘ 1.48 c–e
67.16 ˘ 2.09 f
62.57 ˘ 1.71 c–e
61.93 ˘ 1.69 c,d
4l
4m
4n
4o
4p
4q
4r
4s
4t
EβF
(4-Cl)-benzyl
(2-CH3)-phenyl
(3-CH3)-phenyl
(4-CH3)-phenyl
(4-CH2CH3)-phenyl
(4-F)-phenyl
(4-Cl)-phenyl
(4-OCH3)-phenyl
(2,4-(CH3)2)-phenyl
-
(CH2)2CH3
(CH2)3CH3
(CH2)4CH3
CH(CH3)2
CHCH2(CH3)2
C(CH3)3
cyclohexyl
phenyl
benzyl
4j
4k
a: The repellent activity of each EBF analogue was estimated by the repellent proportion (RP), calculated by the
formula RP = C/(C + T) 100%, where T represents the number of aphids in the treatment arm and C indicates
those in the control arm. Values are mean standard deviation. To determine significant differences in the
mortality of the E F analogues, analysis of variance (One-way ANOVA) was performed followed by Duncan’s
ˆ
˘
β
test (p < 0.05). Different letters indicate significant differences. F-value = 28.05; df1 (degrees of freedom between
groups) = 20; df2 (degrees of freedom within groups) = 189; p < 0.001.

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2.2.2. Aphicidal Activity
Previous publications have indicated that E
βF showed aphicidal activity at high doses [15], and
many compounds with the NHT moiety exhibit high insecticidal activities against major pests [18
such as aphids, plant hoppers, spider mites and other piercing-sucking mouthparts insects. To further
study the bioactivity of our synthesized E F analogues, the aphicidal activity was preliminarily
evaluated in vivo at the concentration 300 µg/mL according to the reported procedure [28].
The results are shown in Table 3. After replacing the E F conjugated double bonds with
NHT, all the analogues displayed aphicidal activity against Myzus persicae, and most analogues
had better activity than the lead compound E F. Particularly, the analogues 4c 4e, and 4p 4s, with
,27],
β
β
β
–
–
mortalities of more than 80%, exhibited similar activity as the commercial insecticide pymetrozine
(81%). Furthermore, a significant difference in mortality was observed between the analogue 4c
and pymetrozine, like between the analogue 4q and pymetrozine. Preliminary structure-activity
relationship analysis found that when R was a straight alkyl chain (number of C < 3), chain length had
a positive effect on aphicidal activity (4a
give negative effect on aphicidal activity. For instance, there were a significant difference (p < 0.05) in
the mortality between 4c and 4f 4d and 4g, and 4d and 4h. The analogues where R was a cyclohexyl,
< 4b < 4c). However, the number of chain branches seems to
,
unsubstituted phenyl or benzyl group exhibited lower aphicidal activity than those where R was a
straight chain. Substituents in the phenyl para-position were beneficial for activity compared with
meta- and ortho-substituents (4o
bisubstituted on the phenyl ring showed good inhibition against aphids.
>
4m « 4n) and the analogues where R was either monosubstituted or
Table 3. Aphicidal activity of the EβF analogues 4a–4t at 300 µg/mL.
Mortality (%) a
Mortality (%) a
(48 h)
Compd.
R
Compd.
R
(48 h)
4a
4b
4c
4d
4e
4f
4g
4h
4i
CH3
CH2CH3
73.32 ˘ 3.28 c
78.26 ˘ 3.53 d,e
86.49 ˘ 2.46 f,g
83.22 ˘ 3.74 e,f
80.18 ˘ 4.66 e
73.85 ˘ 3.51 c,d
70.63 ˘ 4.28 c
63.26 ˘ 2.80 b
61.57 ˘ 3.24 b
60.78 ˘ 3.17 b
59.69 ˘ 3.43 b
4l
4m
4n
4o
4p
4q
4r
4s
4t
(4-Cl)-benzyl
(2-CH3)-phenyl
(3-CH3)-phenyl
(4-CH3)-phenyl
(4-CH2CH3)-phenyl
(4-F)-phenyl
(4-Cl)-phenyl
(4-OCH3)-phenyl
(2,4-(CH3)2)-phenyl
-
72.46 ˘ 2.79 c
42.84 ˘ 3.09 a
44.91 ˘ 1.74 a
79.14 ˘ 2.69 e
80.89 ˘ 2.57 e
88.86 ˘ 4.71 g
82.05 ˘ 3.74 e,f
80.83 ˘ 2.68 e
74.05 ˘ 5.33 c,d
60.25 ˘ 4.42 b
80.68 ˘ 3.83 e
(CH2)2CH3
(CH2)3CH3
(CH2)4CH3
CH(CH3)2
CHCH2(CH3)2
C(CH3)3
cyclohexyl
phenyl
benzyl
4j
4k
EβF
Pymetrozine
-
a: Values are mean
differences in the mortality of the E
˘
standard deviation mortality of E
βF analogues against aphid; to determine significant
βF analogues, analysis of variance (One-way ANOVA) was performed
followed by Duncan’s test (p < 0.05). Different letters indicate significant differences. F-value = 62.74;
df1 (degrees of freedom between groups) = 21; df2 (degrees of freedom within groups) = 110; p < 0.001.
3. Materials and Methods
3.1. General Information
Melting points of the EβF analogues were determined on a Cole-Parmer apparatus equipped with
an uncorrected thermometer (Shanghai precision instrument and Meter Co., Ltd., Shanghai, China).
IR spectra were recorded on neat samples on an IR-435 spectrophotometer (Shimadzu, Kyoto, Japan)
1
using KBr pellets. H-NMR spectra (300 MHz) and 13C-NMR spectra (75 MHz) were recorded on an
1
Avance DPX300 spectrometer (Bruker, Karlsruhe, Germany). H-NMR chemical shifts are reported in
δ
(ppm) relative to the signal of tetramethylsilane (TMS) as internal standard, using CDCl3 as solvent.
The 13C-NMR chemical shifts (
δ
) were reported in parts per million using the solvent peak as reference.
High resolution mass spectra were determined under electron impact (150 eV) conditions using a
Bruker APEX IV instrument. Silica gel (Merck 60, 230–300 mesh, Qingdao Haiyang Chemical Co.,

Molecules 2016, 21, 825
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Ltd., Qingdao, China) was used for column chromatography with petroleum ether and ethyl acetate
as eluents. All starting materials, reagents and solvents were analytical grade reagents and were
commercially available, and all solvents were purified and dried before used.
3.2. Synthesis of EβF Analogues 4a–4t
3.2.1. General Procedure for the Preparation of Intermediate 2
Intermediate 2 was synthesized using the published method [8]. Briefly, phosphorus trichloride
(650 mmol) was added to dried anhydrous pyridine (325 m˝mol) and dried n-hexane (100 mL) in a
500 mL round bottom flask. After the mixture was cooled to 0 C in ice-salt bath, geraniol (16.23 mmol)
˝
˝
and dried n-hexane (20 mL) was dropwise added to the mixture between 0 C and 5 C. The mixture
was stirred for 30 min under 30 mL)
5 ˝C followed by washing with NaCl saturated solution (1
and n-hexane (3 30 mL). The organic phase was combined and separately washed with saturated
NaCl solution and saturated NaHCO3 solution until the pH = 7.0. After dried with anhydrous sodium
´
ˆ
ˆ
sulfate, the organic phase was concentrated under reduced pressure to give the intermediate
liquid, yield 87.5%).
2 (yellow
3.2.2. General Procedure for the Preparation of Intermediate 3a–3t
On the basis of reported method [25], the intermediates 3 containing different R substituents at the
5-position of NHT were prepared by the following general procedure: in a 100 mL round bottom flask,
each different commercial primary amine (58 mmol), nitroguanidine (48 mmol) and 37% formaldehyde
(120 mmol) were dissolved in ethanol (20 mL). The reaction mixture was stirred at 60 ˝C for 3 h and
then was cooled to room temperature. After filtering the solid product was washed with water and
acetone, respectively, and dried to give the white solid intermediates 3a–3t, which were used without
further purification for the synthesis of the EβF analogues 4a–4t.
3.2.3. General Procedure of EβF Analogues 4a–4t
All the EβF analogues were synthesized according to the reported method [29]. Intermediate
2
(2.58 mmol), intermediate
3
(2.58 mmol) as prepared in Sections 3.2.1 and 3.2.2 and dried K2CO3
(2.58 mmol) were added to dried acetonitrile (20 mL) in a 100 mL round bottom flask. The mixture
was refluxed for 5 h and then cooled to room temperature, filtered and concentrated under reduced
pressure. The residue was purified via silica gel column chromatography (petroleum ether/ethyl
acetate = 4:1) to give the EβF analogues 4a–4t. The yields, physicochemical properties and structural
characterization data of 4a–4t were as follows:
N-(1-((E)-3,˝7-Dimethylocta-2,6-dien-1-yl)-5-methyl-1,3,5-triazinan-2-ylidene)nitramide (4a), yellow wax,
m.p. 45–47 C, yield 30.5%. IR(KBr), ν
/cm´1: 3292, 2924, 1589, 1541, 1448, 1381, 1313, 1121; 1H-NMR
(300 MHz, CDCl3):
δ ppm 9.57 (brs, 1H, Het-NH), 5.13–5.18 (m, 1H, C=CH), 5.02–5.06 (m, 1H, C=CH),
4.33 (s, 2H, Het-H), 4.19 (d, 2H, J = 4.41 Hz, Het-H), 4.07 (d, 2H, J = 7.13 Hz, Het-CH2), 2.56 (s, 3H,
N-CH3), 2.01–2.12 (m, 4H, C-CH2CH2-C), 1.64–1.69 (m, 6H, C-(CH3)2), 1.60 (s, 3H, C-CH3); 13C-NMR
(75 MHz, CDCl3): 154.42, 141.00, 131.37, 123.25, 117.55, 66.55, 61.71, 43.51, 39.10, 38.97, 25.83, 25.23,
17.25, 15.83. HRMS (ESI+) m/z calcd for C14H26N5O2, 296.20810 [M + H]+; found: 296.20782.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-ethyl-1,3,5-triazinan-2-ylidene)nitramide (4b), white wax, m.p.
1
40C–42 ˝C, yield 39.2%. IR(KBr),
ν
/cm´1: 3275, 2969, 2925, 2856, 1597, 1556, 1380, 1239; H-NMR
(300 MHz, CDCl3):
δ ppm 9.54 (brs, 1H, Het-NH), 5.15–5.16 (m, 1H, C=CH), 5.05–5.06 (m, 1H, C=CH),
4.37–4.38 (m, 2H, Het-H), 4.24 (s, 2H, Het-H), 4.05 (d, 2H, J = 7.08 Hz, Het-CH2), 2.73 (q, 2H, J = 7.18 Hz,
N-CH2), 2.05–2.10 (m, 4H, C-CH2CH2-C), 1.68–1.70 (m, 6H, C-(CH3)2), 1.60 (s, 3H, C-CH3), 1.14 (t, 3H,
J = 7.22 Hz, C-CH3); 13C-NMR (75 MHz, CDCl3): 154.74, 141.08, 131.48, 123.26, 117.60, 64.31, 59.61,
44.64, 43.44, 39.16, 25.91, 25.29, 17.28, 15.90, 12.67. HRMS (ESI+) m/z calcd for C15H28N5O2, 310.22375
[M + H]+; found: 310.22324.

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N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-propyl-1,3,5-triazinan-2-ylidene)nitramide (4c), white solid, m.p.
˝
1
72–73 C, yield 38.2%. IR(KBr),
(300 MHz, CDCl3): ppm 9.55 (brs, 1H, Het-NH), 5.12–5.17 (m, 1H, C=CH), 5.05–5.06 (m, 1H, C=CH),
ν
/cm´1: 3274, 2959, 2932, 2874, 1587, 1556, 1375, 1288; H-NMR
δ
4.35–4.36 (m, 2H, Het-H), 4.22 (s, 2H, Het-H), 4.05 (d, 2H, J = 7.14 Hz, Het-CH2), 2.62 (t, 2H, J = 7.44 Hz,
N-CH2), 2.05–2.10 (m, 4H, C-CH2CH2-C), 1.68–1.70 (m, 6H, C-(CH3)2), 1.60 (s, 3H, CH3), 0.94 (t, 3H,
J = 7.38 Hz, C-CH3); 13C-NMR (75 MHz, CDCl3): 154.75, 141.03, 131.44, 123.25, 117.60, 64.80, 60.14,
52.36, 43.44, 39.16, 25.95, 25.27, 20.68, 17.27, 15.90, 11.07. HRMS (ESI+) m/z calcd for C16H30N5O2,
324.23940 [M + H]+; found: 324.23911.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-butyl-1,3,5-triazinan-2-ylidene)nitramide (4d), white solid, m.p.
˝
44–46 C, yield 49.2%. IR
ppm 9.52 (brs, 1H, Het-NH), 5.13–5.18 (m, 1H, C=CH), 5.04–5.08 (m, 1H, C=CH), 4.38 (s, 2H, Het-H),
ν
/cm´1: 3276, 2963, 2930, 2861, 1587, 1556, 1536, 1392, 1290, 1237; 1H-NMR:
δ
4.23 (s, 2H, Het-H), 4.05 (d, 2H, J = 7.11 Hz, Het-CH2), 2.66 (t, 2H, J = 6.90 Hz, N-CH2), 2.06–2.10
(m, 4H, C-CH2CH2-C), 1.70 (s, 3H, C-CH3), 1.68 (s, 3H, C-CH3), 1.60 (s, 3H, C-CH3), 1.43–1.52 (m,
2H, C-CH2-C), 1.30–1.40 (m, 2H, C-CH2-C), 0.93 (t, 3H, J = 7.20 Hz, C-CH3); 13C-NMR:
δ ppm 154.81,
141.16, 131.55, 123.24, 117.57, 64.80, 60.18, 50.30, 43.53, 39.21, 29.58, 26.00, 25.31, 19.77, 17.30, 15.97,
13.48. HRMS (ESI+) m/z calcd for C17H32N5O2, 338.25505 [M + H]+; found: 338.25464.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-pentyl-1,3,5-triazinan-2-ylidene)nitramide (4e), white solid, m.p.
˝
49–50 C, yield 30.1%. IR
ppm 9.52 (brs, 1H, Het-NH), 5.12–5.17 (m, 1H, C=CH), 5.03–5.07 (m, 1H, C=CH), 4.38 (s, 2H, Het-H),
ν
/cm´1: 3293, 2955, 2929, 2858, 1587, 1541, 1428, 1395, 1303, 1238; 1H-NMR:
δ
4.22 (s, 2H, Het-H), 4.05 (d, 2H, J = 7.14 Hz, Het-CH2), 2.64 (t, 2H, J = 7.14 Hz, N-CH2), 2.04–2.09 (m,
4H, C-CH2CH2-C), 1.69 (s, 3H, C-CH3), 1.68 (s, 3H, C-CH3), 1.60 (s, 3H, C-CH3), 1.44–1.54 (m, 2H,
C-CH2-C), 1.28–1.34 (m, 4H, C-CH2CH2-C), 0.90 (t, 3H, J = 6.93 Hz, C-CH3); 13C-NMR:
δ ppm 154.78,
141.15, 131.55, 123.24, 117.56, 64.79, 60.16, 50.57, 43.51, 39.21, 28.78, 27.19, 25.99, 25.32, 22.10, 17.32,
15.98, 13.62. HRMS (ESI+) m/z calcd for C18H34N5O2, 352.27070 [M + H]+; found: 352.27066.
N-(1-((E)-3,˝7-Dimethylocta-2,6-dien-1-yl)-5-isopropyl-1,3,5-triazinan-2-ylidene)nitramide (4f), white solid,
m.p. 64–66 C, yield 22.5%. IR ν δ ppm
/cm´1: 3294, 2968, 2923, 2854, 1587, 1552, 1384, 1290; 1H-NMR:
9.51 (brs, 1H, Het-NH), 5.18–5.19 (m, 1H, C=CH), 5.05–5.06 (m, 1H, C=CH), 4.45–4.46 (m, 2H, Het-H),
4.32 (s, 2H, Het-H), 4.05 (d, 2H, J = 7.17 Hz, Het-CH2), 2.88–3.07 (m, 1H, C-CH-C), 2.06–2.10 (m, 4H,
C-CH2CH2-C), 1.68–1.71 (m, 6H, C-(CH3)2), 1.58–1.60 (m, 3H, C-CH3), 1.16 (s, 3H, C-CH3) , 1.14 (s, 3H,
C-CH3); 13C-NMR:
δ ppm 155.39, 141.04, 131.47, 123.26, 117.62, 62.62, 57.57, 48.21, 47.34, 43.44, 39.18,
25.94, 25.29, 20.80, 18.82, 17.28, 15.91. HRMS (ESI+) m/z calcd for C16H30N5O2, 324.23940 [M + H]+;
found: 324.23914.
N-(1-((E)-3,˝7-Dimethylocta-2,6-dien-1-yl)-5-isobutyl-1,3,5-triazinan-2-ylidene)nitramide (4g), white solid,
m.p. 87–88 C, yield 52.8%. IR ν
/cm´1: 3279, 2961, 2926, 2871, 2853, 1587, 1554, 1535, 1380, 1289, 1239;
1H-NMR:
δ ppm 9.56 (brs, 1H, Het-NH), 5.15–5.20 (m, 1H, C=CH), 5.06–5.10 (m, 1H, C=CH), 4.36 (s,
2H, Het-H), 4.22 (s, 2H, Het-H), 4.07 (d, 2H, J = 7.11 Hz, Het-CH2), 2.45 (d, 2H, J = 7.26 Hz, N-CH2),
2.08–2.12 (m, 4H, C-CH2CH2-C), 1.74 (s, 3H, C-CH3), 1.71 (s, 3H, C-CH3), 1.70 (s, 1H, C-CH), 1.62 (s,
3H, C-CH3), 0.96 (s, 3H, C-CH3), 0.94 (s, 3H, C-CH3); 13C-NMR:
δ ppm 154.91, 141.22, 131.60, 123.24,
117.53, 65.44, 60.83, 58.87, 43.57, 39.23, 26.56, 26.04, 25.34, 20.05, 17.32, 16.00. HRMS (ESI+) m/z calcd for
C17H32N5O2, 338.25505 [M + H]+; found: 338.25476.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(tert-butyl)-1,3,5-triazinan-2-ylidene)nitramide (4h), white solid,
m.p. 93–95 ˝C, yield 40.3%. IR /cm´1: 3297, 2965, 2923, 2877, 1595, 1553, 1365, 1332; 1H-NMR:
ν δ
ppm 9.56 (brs, 1H, Het-NH), 5.22–5.26 (m, 1H, C=CH), 5.05–5.07 (m, 1H, C=CH), 4.52 (brs, 2H, Het-H),
4.36 (brs, 2H, Het-H), 4.08 (d, 2H, J = 7.26 Hz, C=CH), 2.03–2.09 (m, 4H, C-CH2CH2-C), 1.68–1.72 (m,
6H, C-(CH3)2), 1.46–1.48 (m, 3H, CH3), 1.21 (s, 9H, C(CH3)3); 13C-NMR:
δ ppm 155.61, 140.99, 131.46,
123.27, 117.66, 60.56, 55.63, 54.37, 43.28, 39.17, 27.98, 25.94, 25.29, 17.28, 15.89. HRMS (ESI+) m/z calcd
for C17H32N5O2, 338.25505 [M + H]+; found: 338.25485.

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N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-cyclohexyl-1,3,5-triazinan-2-ylidene)nitramide (4i), white solid,
m.p. 99–100 ˝C, yield 63.8%. IR /cm´1: 3287, 2926, 2853, 1586, 1554, 1536, 1383, 1240; 1H-NMR:
ν
δ
ppm 9.50 (brs, 1H, Het-NH), 5.15–5.20 (m, 1H, C=CH), 5.04–5.06 (m, 1H, C=CH), 4.46–4.47 (m, 2H,
Het-H), 4.33 (s, 2H, Het-H), 4.05 (d, 2H, J = 7.17 Hz, Het-CH2), 2.64–2.65 (m, 1H, 1-cyclohexyl-H),
2.01–2.10 (m, 4H, C-CH2CH2-C), 1.77–1.91 (m, 4H, 2,6-cyclohexyl-H), 1.68–1.71 (m, 6H, C-(CH3)2),
1.60 (s, 3H, CH3), 1.14–1.30 (m, 6H, 3,4,5-cyclohexyl-H); 13C-NMR:
δ ppm 155.36, 141.03, 131.46, 123.24,
117.60, 62.21, 57.16, 56.02, 43.37, 39.19, 30.71, 25.98, 25.29, 25.20, 24.56, 17.28, 15.94. HRMS (ESI+) m/z
calcd for C19H34N5O2, 364.27070 [M + H]+; found: 364.27069.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-phenyl-1,3,5-triazinan-2-ylidene)nitramide (4j), white solid, m.p.
108–110 ˝C, yield 47.6%. IR /cm´1: 3284, 2969, 2911, 2847, 1714, 1668, 1580, 1551, 1493, 1432, 1382,
ν
1314; 1H-NMR:
(m, 2H, C=CH), 4.90–4.91 (m, 2H, Het-H), 4.76 (s, 2H, Het-H), 4.11 (d, 2H, J = 7.14 Hz, Het-CH2),
2.01–2.07 (m, 4H, C-CH2CH2-C), 1.67–1.68 (m, 6H, C-(CH3)2), 1.60 (s, 3H, C-CH3); 13C-NMR:
ppm
δ ppm 9.75 (s, 1H, Het-NH), 7.30–7.36 (m, 2H, Ar-H), 7.02–7.12 (m, 3H, Ar-H), 5.05–5.08
δ
155.32, 146.21, 141.63, 131.50, 129.24, 123.31, 123.12, 118.90, 117.27, 63.75, 59.30, 43.61, 39.15, 25.93, 25.31,
17.35, 15.97. HRMS (ESI+) m/z calcd for C19H28N5O2, 358.22375 [M + H]+; found: 358.22360.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-benzyl-1,3,5-triazinan-2-ylidene)nitramide (4k), white solid,
m.p. 76–77 ˝C, yield 55.6%. IR /cm´1: 3274, 3027, 2966, 2921, 2857, 1670, 1585, 1553, 1367, 1291;
ν
1H-NMR:
(m, 2H, Het-H), 4.22 (s, 2H, Het-H), 4.04 (d, 2H, J = 7.17 Hz, Het-CH2), 3.84 (s, 2H, N-CH2), 2.01–2.07
(m, 4H, C-CH2CH2-C), 1.67 (s, 3H, C-CH3), 1.58 (d, 6H, J = 7.32 Hz, C-(CH3)2); 13C-NMR:
ppm 154.89,
δ ppm 9.59 (brs, 1H, Het-NH), 7.31–7.37 (m, 5H, Ar-H), 5.03–5.16 (m, 2H, C=CH), 4.36–4.37
δ
141.18, 136.07, 131.53, 128.59, 128.34, 127.67, 123.30, 117.51, 64.18, 59.79, 54.82, 43.62, 39.21, 25.92, 25.34,
17.35, 15.87. HRMS (ESI+) m/z calcd for C20H30N5O2, 372.23940 [M + H]+; found: 372.23917.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(4-chlorobenzyl)-1,3,5-triazinan-2-ylidene)nitramide (4l), white
solid, m.p. 65–67 ˝C, yield 55.4%. IR /cm´1: 3283, 2982, 2967, 2914, 2888, 2853, 1588, 1546, 1435,
ν
1387, 1297, 1244; 1H-NMR:
δ ppm 9.50 (brs, 1H, Het-NH), 7.19–7.30 (m, 4H, Ar-H), 5.10–5.14 (m, 1H,
C=CH), 4.98–5.03 (m, 1H, C=CH), 4.38 (s, 2H, Het-H), 4.18 (s, 2H, Het-H), 3.99 (d, 2H, J = 7.14 Hz,
Het-CH2), 1.94–2.05 (m, 4H, C-CH2CH2-C), 1.62 (d, 3H, J = 0.78 Hz, C-CH3), 1.55–1.57 (m, 6H, C-CH3);
13C-NMR:
δ ppm 154.78, 141.20, 134.84, 133.27, 131.50, 129.88, 128.39, 123.25, 117.49, 64.10, 59.84, 54.04,
43.51, 39.19, 25.90, 25.32, 17.33, 15.85. HRMS (ESI+) m/z calcd for C20H29ClN5O2, 406.20043 [M + H]+;
found: 406.20068.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(2-methylphenyl)-1,3,5-triazinan-2-ylidene)nitramide
(
4m),
white solid, m.p. 72–74 ˝C, yield 29.2%. IR
ν
/cm´1: 3306, 3025, 2965, 2925, 1669, 1591, 1544, 1494,
1
1423, 1386, 1276; H-NMR:
δ ppm 9.72 (brs, 1H, Het-NH), 7.06–7.23 (m, 4H, Ar-H), 5.02–5.04 (m,
2H, C=CH), 4.71 (s, 2H, Het-H), 4.58 (s, 2H, Het-H), 4.11 (d, 2H, J = 7.27 Hz, Het-CH2), 2.30 (s, 3H,
Ar-CH3), 1.95–2.04 (m, 4H, C-CH2CH2-C), 1.64 (d, 6H, J = 4.21 Hz, C-(CH3)2), 1.67 (s, 3H, C-CH3);
13C-NMR:
δ ppm 155.51, 145.73, 141.62, 132.14, 131.49, 131.19, 126.78, 125.24, 123.30, 120.73, 117.06,
64.33, 59.95, 43.48, 39.13, 25.91, 25.28, 17.50, 17.35, 15.92. HRMS (ESI+) m/z calcd for C20H30N5O2,
372.23940 [M + H]+; found: 372.23889.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(3-methylphenyl)-1,3,5-triazinan-2-ylidene)nitramide (4n), white
solid, m.p. 101–102 ˝C, yield 25.8%. IR /cm´1: 3283, 3012, 2969, 2916, 2847, 1666, 1606, 1578, 1551,
ν
1492, 1430, 1383, 1290; 1H-NMR:
δ ppm 9.53 (brs, 1H, Het-NH), 7.18 (t, 1H, J = 7.82 Hz, Ar-H), 6.91–6.96
(m, 2H, Ar-H), 6.81 (d, 1H, J = 7.23 Hz, Ar-H), 5.00–5.05 (m, 2H, C=CH), 4.90 (d, 4H, J = 6.53 Hz, Het-H),
3.95 (d, 2H, J = 6.85 Hz, Het-CH2), 2.27 (s, 3H, Ar-CH3),1.96–2.02 (m, 4H, C-CH2CH2-C), 1.68 (s, 3H,
CH3) , 1.62 (s, 3H, CH3) , 1.55 (s, 3H, CH3); 13C-NMR:
δ ppm 155.38, 146.21, 141.65, 139.18, 131.58,
129.09, 124.05, 123.27, 119.63, 117.30, 115.95, 63.68, 59.43, 43.64, 39.21, 25.95, 25.32, 21.27, 17.36, 15.99.
HRMS (ESI+) m/z calcd for C20H30N5O2, 372.23940 [M + H]+; found: 372.23911.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(4-methylphenyl)-1,3,5-triazinan-2-ylidene)nitramide (4o), white
solid, m.p. 135–136 ˝C, yield 30.1%. IR /cm´1: 3278, 3010, 2968, 2914, 2853, 1580, 1551, 1497, 1432,
ν

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1
1382, 1286; H-NMR:
δ
ppm 9.71 (brs, 1H, Het-NH), 7.12 (d, 2H, J = 8.40 Hz, Ar-H), 6.94 (d, 2H,
J = 8.49 Hz, Ar-H), 5.05–5.07 (m, 2H, C=CH), 4.86 (s, 2H, Het-H), 4.71 (s, 2H, Het-H), 4.09 (d, 2H,
J = 7.17 Hz, Het-CH2), 2.30 (s, 3H, Ar-CH3), 2.02–2.06 (m, 4H, C-CH2CH2-C), 1.67 (s, 6H, C-(CH3)2),
1.60 (s, 3H, C-CH3); 13C-NMR:
δ ppm 155.37, 143.87, 141.60, 133.02, 131.56, 129.82, 123.32, 119.19, 117.26,
64.12, 59.70, 43.69, 39.18, 25.94, 25.32, 20.23, 17.36, 16.01. HRMS (ESI+) m/z calcd for C20H30N5O2,
372.23940 [M + H]+; found: 372.23901.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(4-ethylphenyl)-1,3,5-triazinan-2-ylidene)nitramide (4p), white
solid, m.p. 76–78 ˝C, yield 43.1%. IR /cm´1: 3286, 2967, 2929, 2857, 1579, 1546, 1532, 1380, 1240;
ν
1H-NMR:
δ ppm 9.72 (brs, 1H, Het-NH), 7.15–7.19 (m, 2H, Ar-H), 6.96–7.01 (m, 2H, Ar-H), 5.06–5.12
(m, 2H, C=CH), 4.90 (t, 2H, J = 1.08 Hz, Het-H), 4.75 (s, 2H, Het-H), 4.12 (d, 2H, J = 7.17 Hz, Het-CH2),
2.63 (q, 2H, J = 7.62 Hz, Ar-CH2), 2.03–2.10 (m, 4H, C-CH2CH2-C), 1.70 (s, 6H, C-CH3), 1.63 (s, 3H,
C-CH3), 1.24 (t, 3H, J = 7.59 Hz, C-CH3); 13C-NMR:
δ ppm 155.39, 144.03, 141.64, 139.50, 131.58, 128.65,
123.30, 119.28, 117.27, 64.10, 59.76, 43.68, 39.20, 27.71, 25.96, 25.32, 17.36, 15.99, 15.19. HRMS (ESI+) m/z
calcd for C21H32N5O2, 386.25505 [M+H]+; found: 386.25449.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(4-fluorophenyl)-1,3,5-triazinan-2-ylidene)nitramide (4q), white
solid, m.p. 101–103 ˝C, yield 59.2%. IR /cm´1: 3281, 2975, 2933, 2915, 2847, 1580, 1552, 1533, 1382,
ν
1285, 1237; 1H-NMR:
4.89 (t, 2H, J = 1.05 Hz, Het-H), 4.72 (s, 2H, Het-H), 4.11 (d, 2H, J = 7.20 Hz, Het-CH2), 1.98–2.08 (m, 4H,
C-CH2CH2-C), 1.69 (s, 6H, C-CH3), 1.62 (s, 3H, C-CH3); 13C-NMR:
ppm 158.89 (d, JC-F = 242.36 Hz),
δ ppm 9.73 (brs, 1H, Het-NH), 7.03–7.05 (m, 4H, Ar-H), 5.05–5.10 (m, 2H, C=CH),
δ
155.39, 142.67 (d, JC-F = 2.81 Hz), 141.92, 131.68, 123.16, 121.22 (d, JC-F = 8.03 Hz), 117.07, 115.96
(d, JC-F = 22.50 Hz), 64.39, 60.00, 43.65, 39.18, 25.94, 25.30, 17.33, 15.99. HRMS (ESI+) m/z calcd for
C19H27FN5O2, 376.21433 [M + H]+; found: 376.21405.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(4-chlorophenyl)-1,3,5-triazinan-2-ylidene)nitramide (4r), white
solid, m.p. 134–136 ˝C, yield 20.3%. IR /cm´1: 3391, 3278, 2969, 2912, 2852, 1579, 1552, 1493, 1434,
ν
1383, 1287, 821; 1H-NMR:
Ar-H), 5.04–5.05 (m, 2H, C=CH), 4.91–4.97 (m, 4H, Het-H), 3.94 (d, 2H, J = 6.87 Hz, Het-CH2), 1.91–2.00
(m, 4H, C-CH2CH2-C), 1.66 (s, 3H, C-CH3) , 1.62 (s, 3H, C-CH3) , 1.55 (s, 3H, C-CH3); 13C-NMR:
ppm
δ ppm 9.56 (brs, 1H, Het-NH), 7.32–7.36 (m, 2H, Ar-H), 7.15–7.19 (m, 2H,
δ
155.34, 144.88, 142.04, 131.69, 129.28, 128.54, 123.18, 120.42, 117.06, 63.79, 59.44, 43.68, 39.19, 25.95, 25.32,
17.36, 16.01. HRMS (ESI+) m/z calcd for C19H27ClN5O2, 392.18478 [M + H]+; found: 392.18484.
N-(1-((E)-3,7-Dimethylocta-2,6-dien-1-yl)-5-(4-methoxyphenyl)-1,3,5-triazinan-2-ylidene)nitramide
white solid, m.p. 91–93 ˝C, yield 38.5%. IR /cm´1: 3291, 3062, 2965, 2908, 2854, 1672, 1594, 1542,
1511, 1457, 1385, 1292; 1H-NMR:
ppm 9.52 (brs, 1H, Het-NH), 7.04–7.08 (m, 2H, Ar-H), 6.85–6.90
(4s),
ν
δ
(m, 2H, Ar-H), 5.02–5.06 (m, 1H, C=CH), 4.93–4.97 (m, 1H, C=CH), 4.83 (d, 4H, J = 8.78 Hz, Het-H),
3.94 (d, 2H, J = 6.83 Hz, Het-CH2), 3.70 (s, 3H, Ar-OCH3), 1.91–2.00 (m, 4H, C-CH2CH2-C), 1.66 (s, 3H,
C-CH3) , 1.62 (s, 3H, C-CH3) , 1.55 (s, 3H, C-CH3); 13C-NMR:
δ ppm 155.81, 155.32, 141.52, 139.87,
131.50, 123.30, 121.03, 117.26, 114.42, 64.64, 60.11, 55.12, 43.60, 39.15, 25.94, 25.30, 17.33, 15.96. HRMS
(ESI+) m/z calcd for C20H30N5O3, 388.23432 [M + H]+; found: 388.23370.
N-(1-((E)-3,7-Dimethylo˝cta-2,6-dien-1-yl)-5-(2,4-dimethylphenyl)-1,3,5-triazinan-2-ylidene)nitramide (4t),
white solid, m.p. 88–90 C, yield 16.3%. IR ν
/cm´1: 3292, 2960, 2928, 2856, 1666, 1592, 1552, 1507, 1458,
1380, 1269; 1H-NMR:
δ
ppm 9.48 (brs, 1H, Het-NH), 7.03 (s, 1H, Ar-H), 6.94 (s, 2H, Ar-H), 4.94–5.04 (m,
2H, C=CH), 4.60–4.66 (s, 4H, Het-H), 3.96 (d, 2H, J = 6.99 Hz, Het-CH2), 2.21 (s, 6H, Ar-CH3), 1.87–1.99
(m, 4H, C-CH2CH2-C), 1.62 (s, 3H, C-CH3) , 1.60 (s, 3H, C-CH3) , 1.55 (s, 3H, C-CH3); 13C-NMR:
δ
ppm 155.53, 143.26, 141.49, 134.90, 131.99, 131.84, 131.47, 127.23, 123.34, 120.71, 117.12, 64.57, 60.10,
43.52, 39.14, 25.92, 25.26, 20.32, 17.38, 17.32, 15.93. HRMS (ESI+) m/z calcd for C21H32N5O2, 386.25505
[M + H]+; found: 386.25500.

Molecules 2016, 21, 825
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3.3. X-ray Diffraction
Single crystals of 4r were C19H26ClN5O2 (CCDC 1437627 contains the supplementary
crystallographic data for this paper. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK; Fax: +44 1223 336033; E-mail: deposit@ccdc.cam.ac.uk), shown in Figure 1). A suitable
crystal was selected an analyzed on a SuperNova, Dual, Cu at zero, Atlas diffractometer (Agilent, CA,
USA) PW. The crystal was kept at 180.01(10) K during data collection. Using Olex2 [30], the structure
was solved with the Superflip [31] structure solution program using Charge Flipping and refined with
the Shelx [32] refinement package using Least Squares minimisation.
3.4. Stability Test
The EβF and analogues 4r were dissolved in methanol (chromatographically pure), respectively.
After exposure to air for 48 h at room temperature, their changes of content were analyzed by
high performance liquid chromatography (HPLC) on a LC-1AT HPLC instrument (Shimadzu).
Chromatographic experiments were performed on C18 reversed-phase column (4.5 mm
ˆ
250 mm,
5
µ
m), the mobile phase was methanol and water (80:20); the detection wavelength was 245 nm,
˝
column temperature was 25 C, the flow rate was 0.7 mL/min and the injection volume was 5 µL.
3.5. Biological Activity Test
3.5.1. Repellent Assays
The repellent response of Myzus persicae to the EβF analogues was investigated with a glass
T-tube (a two-way olfactometer) olfactometer [33] (one arm was used as “treatment” arm while the
other was as “control” arm). A total air flow 0.4 L/min (each arm was 0.2 L/min) was introduced
into the olfactometer, which firstly went through activated carbon to purify air flow and then pass
through distilled water. Thus two well separated and purified air flow went continuously through
the olfactometer arms. A´s5a “treatment” arm, standard solutions (2.5
µL, dissolved in hexane with
final concentration 2
ˆ
10 g/10 µ
L) of the test compounds were applied to filter paper strips (1 cm2
diameter). The solvent was allowed to evaporate for 30 s before the filter paper strip was placed in the
glass stimulus chamber. For control, 2.5 L n-hexane as solvent was placed in the chamber of “control”
µ
arm and operated same as “treatment” arm. The whole olfactometer was washed with ethanol and
hexane and dried by air before each test.
Apterous adult Myzus persicae were used in this assay. A total of twenty aphids were introduced
at the center of the olfactometer arms and allowed freedom to walk toward either arm. After 15 min,
the number of aphids, which moved more than 2 cm distance to the olfactometer center, was recorded
as treatment arm or control arm. The experiment was replicated 10 times with each analogue. The
repellent activity of each EBF analogue was estimated by the repellent proportion (RP), the modification
of excess proportion index [34], calculated by the formula RP = C/(C + T)
the number of aphids in the arm treated with the tested solutions and C indicates those in the control
arm. The numbers of aphids in control and treatment arm were compared statistically with that of
ˆ
100%, where T represents
SPSS Statistics version 21 (IBM) by paired t-test. Also the repellent proportion of the EβF analogues
was analyzed statistically with that of SPSS Statistics version 21 (IBM) using one-way analysis of
variance (ANOVA) followed by Duncan’s test at p < 0.05.
3.5.2. Aphicidal Assays
The aphicidal activity of the E
reported procedure [28]. All the test compounds were dissolved in acetone to a concentration of
3000 g/mL and then diluted with 0.5% Tween 80 to the test concentration 300 g/mL. Soybean
plant leaf discs of about 3 cm diameter were dipped into the test solutions for 10 s. Using the same
test concentration, the discs dipped into E F solution were set as the positive control while the discs
βF analogues against Myzus persicae was evaluated using the
µ
µ
β

Molecules 2016, 21, 825
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dipped into 0.5% Tween 80 were set as the negative control. After air-drying, the treated leaf discs were
placed individually into bioassay polyvinyl plates (10 cm 13 cm 2.5 cm, each plate had twelves
(3 4) holes of 3.0 cm diameter each) with 1% agar to keep moist. And then, the discs were infested
with 20 3 apterous adult aphids and kept in an incubator with constant temperature (25
1 ˝C)
ˆ
ˆ
ˆ
˘
˘
and light period (light:dark = 8:16) for 48 h. Each treatment was performed six times. The number of
dead aphids was counted, and then mortality rates were corrected using Abbott’s formula [35]. The
aphicidal activity of the EβF analogues were compared with that of SPSS Statistics version 21 (IBM)
using one way analysis of variance (ANOVA) followed by Duncan’s test at p < 0.05.
4. Conclusions
In summary, a series of novel (E)-
conjugated double bonds of E F with 2-nitroiminohexahydro-1,3,5-triazine. All the title compounds
were synthesized via the nucleophilic substitution reaction of intermediates and . The performed
bioassay proved that some analogues, such as 4r and 4t, showed good repellent activity against
Myzus persicae. Particularly, the analogue 4r, with more stability than the lead E F, also exhibited
β-farnesene analogues were designed by replacing the
β
2
3
β
similar aphicidal activity as pymetrozine. Therefore, 4r would be a promising lead for the further
optimization. In the meantime, the structure-activity relationship provided the valuable clues for
the design of new EβF analogues. Introducing phenyl rather than alkyl, cyclohexyl or benzyl at
5 positon of 2-nitroiminohexahydro-1,3,5-triazine is strongly recommended and it is favorable to use
electron-withdrawing groups in the para-position or disubstitution in the benzene ring.
Supplementary Materials: Supplementary materials can be accessed at: http://www.mdpi.com/1420-3049/
21/7/825/s1.
Acknowledgments: This study was supported by National Natural Science Foundation of China (NSFC)
(No. 21132003, 31371946).
Author Contributions: Y. Qin and J. Zhang synthesized all of the intermediates and new compounds; Y. Qin and
D. Song ran the bioassay evaluation and statistics analysis; Y. Qin drafted the paper; and X. Yang and H. Duan
started the project, designed the molecules and revised this paper.
Conflicts of Interest: The authors declare no conflict of interest.
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Sample Availability: Samples of the compounds 4a–4t are available from the authors.
©
2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC-BY) license (http://creativecommons.org/licenses/by/4.0/).