Facile synthesis of novel dithioacetal-naphthalene derivatives as potential activators for plant resistance induction

Article abstract of DOI:10.1039/c9ra06843k

In this paper, a series of novel dithioacetal-naphthalenes were designed and synthesized for plant immunity. Their antiviral activities were evaluated against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). The results indicated that most compounds exhibited better activity against CMV than against TMV. These dithioacetal derivatives also displayed good bacterial activity against rice bacterial leaf blight. Among them, compound S16 exhibited relatively good anti-CMV, anti-TMV, and antibacterial activity. Structure-activity relationships indicated that introducing the naphthalene moiety enhanced their activities for plant resistance induction. Therefore, the basic motif of compound S16 could be the most promising candidate for further structural optimization to develop a potential activator for plant resistance induction.

Full text of DOI:10.1039/c9ra06843k

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Facile synthesis of novel dithioacetal–naphthalene
derivatives as potential activators for plant
resistance induction†
Cite this: RSC Adv., 2019, 9, 32375
a
b
R. J. Ji,‡a W. M. Shi,‡a D. Y. Tian,a G. P. Zhang
*
*
and H. Wang
In this paper, a series of novel dithioacetal–naphthalenes were designed and synthesized for plant
immunity. Their antiviral activities were evaluated against tobacco mosaic virus (TMV) and cucumber
mosaic virus (CMV). The results indicated that most compounds exhibited better activity against CMV
than against TMV. These dithioacetal derivatives also displayed good bacterial activity against rice
bacterial leaf blight. Among them, compound S16 exhibited relatively good anti-CMV, anti-TMV, and
antibacterial activity. Structure–activity relationships indicated that introducing the naphthalene moiety
enhanced their activities for plant resistance induction. Therefore, the basic motif of compound S16
could be the most promising candidate for further structural optimization to develop a potential
activator for plant resistance induction.
Received 29th August 2019
Accepted 24th September 2019
DOI: 10.1039/c9ra06843k
rsc.li/rsc-advances
elicitors. Based on plant immune resistance, these elicitors are
developed into antivirus agents and used for the prevention and
treatment of plant virus.10–14 In the development of the chemical
antivirus, people mainly consider the virus itself. Many of these
reported drugs suffer from low effectiveness and narrow-
spectrum antiviral property. In addition, the absolute parasite
of the virus on the host is closely related to the plant. In general,
two factors of virus inhibition and plant activation must be
considered together to develop efficient broad-spectrum anti-
viral agents.
Dithioacetal and its derivatives have extensive biological
activities, such as antibacterial,15 antileishmanial,16 antiviral,17
and antifungal.18,19 Song et al. found that dithioacetal derivative
6f (Fig. 1) exerted markedly curative and protective activities
against PVY and CMV.20 Further research results by this group
showed that dithioacetal C14 (Fig. 1) elicited excellent curative
and protective activities against PVY, CMV and TMV.21 Their
mechanism associated with the change of SOD, CAT, and POD
was also demonstrated. Based on above, introduction of plant
immune elicitors, dithiacetal compounds could be developed
into novel antiviral agents with effectiveness and spectrum
width.
Introduction
Plant viruses are pathogenic to plants, infecting many
plants, especially vegetables, including pepper, tomato,
cucumber, and so on.1 Owing to the diversity of virus
species, the different transmission mechanisms and the
mutability of viruses under eld conditions, it is extremely
difficult to control viral infection,2 which results in massive
economic losses each year.3–5 Although numerous chemical
and biological controls have been applied, there have been
few efficient compounds that can protect plants completely
from virus infection.6 In the eld, the reported antiviral
agents,7 such as ninominomycin, dufulin, ribavirin, len-
tinan polysaccharide, emodinmethyl ether, morinanidine
hydrochloride, chlorbromo-isocyanurate, DHT, DADHT,
and chitooligosaccharide, are oen effective only against
one virus while disabled against the others. Furthermore,
the agents with a preventive effect are less than 60% among
the antiviral agents.8 Therefore the development of new
antiviral agents with an efficient broad-spectrum is
extremely urgent.
In fact, plants have self-defend system and can resist the
infection of bacteria, mold and viruses.9 Such self-defensive
ability is commonly induced by some external or internal
aChemistry and Material Science College, Huaibei Normal University, Huaibei 235000,
China. E-mail: hbzgp-1@163.com
bInstitute for Plant Protection and Soil Science, Hubei Academy of Agricultural
Sciences, Nanhu Road 6, Wuhan 430064, China. E-mail: wanghua4@163.com
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c9ra06843k
Fig. 1 The structures of the reported dithioacetal compounds with
‡ These authors contributed to this work equally.
high activity.
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Table 1 Optimizations of reaction conditions for the synthesis of S1
catalyzed by ionic liquid (BIL)
Naproxen acetic acid and naproxen sodium derivatives are
important plant regulators for agriculture.22 These regulators
can promote plant growth and chlorophyll synthesis. Especially
it can promote the formation of adventitious roots and roots
with fruit expansion and anti-falling function. We then intro-
duced the plant regulated naphthalene group to dithioacetal
skeleton (Fig. 2). Moreover, their bioactivities against cucumber
mosaic virus and tobacco mosaic virus were subsequently
evaluated and preliminary structure–activity relationship was
concluded.
Entrya
Catalyst (mol%)
Solvent
Temp/ꢀC
Time
Yieldb/%
1
2
3
4
5
6
7
8
—
DCM
DCM
DCM
CH3CN
DCE
DOX
DCE
DCE
40
40
40
80
80
110
80
80
6
6
6
6
6
6
12
12
0
ZrCl4 (10)
71
81
67
97
87
96
69
BIL–HSO4 (10)
BIL–HSO4 (10)
BIL–HSO4 (10)
BIL–HSO4 (10)
BIL–HSO4 (5)
BIL–HSO4 (1)
a
Reaction conditions: aldehyde (1.0 mmol), thiol (1.0 mmol), solvent
(1.0 mL). b Isolated yield.
Results and discussion
The condensation reaction of aromatic aldehyde bearing
naphthalene ring (M1) with allyl mercaptan was chosen as
a model reaction to optimize the reaction conditions and the
results are summarized in Table 1. It was observed that the
reaction failed to give the product without the catalyst (Table 1,
entry 1). In initial studies, different catalysts were screened in
dichloromethane as the solvent (1 mL) at 40 ꢀC (Table 1, entry 2
and 3). It was found that the acid ionic liquid (BIL) could
effectively catalyzed the condensation reaction. The effects of
solvents were then evaluated by using ionic liquid (BIL) as the
catalyst (Table 1, entry 3–6). Dichloroethane (Table 1, entry 5)
was found to be an optimal solvent, giving S1 in a good yield (up
to 97%). Almost no change in reactivity was observed when the
loading of BIL–HSO4 was reduced from 10 mol% to 5 mol%
(Table 1, entries 5 and 7). However, the product decreased from
97% to 69% when the catalyst load was reduced from 5 mol% to
1 mol% (Table 1, entries 7 and 8).
The reusability of the catalyst (BIL–HSO4) was investigated
and the results are described in Fig. 3. The reaction mixture was
concentrated under reduced pressure to remove the dichloro-
methane. 20 mL water was added to the mixture. Then the
catalyst was recovered by using simple ltration technique. The
ltrate containing ionic liquid was dried over vacuum to remove
excess water. This catalyst was directly subjected to the
condensation reaction using the model reaction with our opti-
mized reaction conditions. It is important to note that the
recycled catalysts produced excellent yields of dithioacetal (S1)
in 91–94%, respectively (Fig. 3). It was observed that the yields
were consistent without signicant loss in its catalytic activity.
Under these optimized reaction conditions (Table 1, entry 7),
substituted aldehydes bearing naphthalene ring (M1–M6),
using acid ionic liquid (BIL),23 reacted with different thiols to
generate novel dithioacetals S1–S16 with excellent yields of 83–
97%.
First, compounds S1–S16 were measured for their phytotoxic
activity against tobacco.24 The data of phytotoxic activity at 500
mg mLꢁ1 indicated that compounds S1–S16 showed no toxicity
to the tested plant.
The in vivo anti-TMV activities of target compounds S1–S16
at the concentration of 500 mg mLꢁ1 were evaluated through the
half leaf method.25–29 The results were shown in Table 1. Ning-
nanmycin and dufulin were used as the controls. Most of the
title compounds exhibited good antiviral activities against CMV.
Compounds S5, S8, S12 and S16 possessed excellent curative
and protective activities from 61.5% to 71.3%, which was
signicantly greater than those of the controls with the vicinity
of 50%. Compounds S1, S4, S9 and S13 exhibited good curative
and protective activities with 55% or so, which were slightly
exceeded than those of controls. Other compounds maintained
moderate antiviral activities. The results of the activity against
TMV showed that the target compounds displayed common
Fig. 3 Reusability of ionic liquid (BIL–HSO4) for the synthesis of
compound S1.
Fig. 2 The synthetic routes of novel dithioacetal derivatives.
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Table 2 Antiviral activity of the title compounds (S1–S16) against TMV and CMV at 500 mg mLꢁ1a
Anti-TMV
Anti-CMV
Curative activity
(%)
Protective activity
(%)
Protective activity
(%)
Compd
Curative activity (%)
S1
S2
S3
S4
S5
S6
S7
S8
45.3 ꢂ 2.5%
31.7 ꢂ 2.4%
35.8 ꢂ 2.5%
32.5 ꢂ 1.9%
45.9 ꢂ 2.4%
34.1 ꢂ 2.1%
39.6 ꢂ 3.0%
40.6 ꢂ 3.4%
41.2 ꢂ 2.4%
34.8 ꢂ 1.8%
50.0 ꢂ 2.7%
32.4 ꢂ 3.6%
40.1 ꢂ 2.7%
39.3 ꢂ 2.5%
45.1 ꢂ 2.6%
49.6 ꢂ 2.4%
46.3 ꢂ 2.1%
53.1 ꢂ 1.7%
37.8 ꢂ 2.2%
16.2 ꢂ 3.1%
26.7 ꢂ 2.0%
28.2 ꢂ 2.1%
38.6 ꢂ 5.3%
34.9 ꢂ 1.9%
37.6 ꢂ 2.7%
35.3 ꢂ 2.8%
42.6 ꢂ 3.8%
29.0 ꢂ 3.3%
47.4 ꢂ 2.4%
18.4 ꢂ 3.1%
36.4 ꢂ 2.3%
34.5 ꢂ 2.4%
44.7 ꢂ 2.1%
48.1 ꢂ 1.7%
49.4 ꢂ 2.6%
63.4 ꢂ 2.4%
53.2 ꢂ 1.6%
36.6 ꢂ 2.1%
47.5 ꢂ 2.2%
57.4 ꢂ 1.3%
66.1 ꢂ 2.8%
44.2 ꢂ 2.3%
47.1 ꢂ 2.6%
61.5 ꢂ 3.1%
56.4 ꢂ 2.3%
46.1 ꢂ 1.9%
41.7 ꢂ 2.2%
62.9 ꢂ 1.5%
59.6 ꢂ 2.1%
49.1 ꢂ 2.8%
65.3 ꢂ 1.9%
71.5 ꢂ 1.4%
51.3 ꢂ 1.8%
48.7 ꢂ 2.1%
57.8 ꢂ 2.3%
31.2 ꢂ 1.9%
46.9 ꢂ 1.7%
59.3 ꢂ 2.2%
68.3 ꢂ 2.4%
41.6 ꢂ 1.6%
44.9 ꢂ 2.1%
64.4 ꢂ 2.0%
54.8 ꢂ 1.6%
48.7 ꢂ 3.5%
43.8 ꢂ 2.6%
68.3 ꢂ 2.0%
56.3 ꢂ 1.5%
46.4 ꢂ 2.2%
63.1 ꢂ 1.7%
69.1 ꢂ 2.1%
53.1 ꢂ 2.1%
49.4 ꢂ 2.6%
S9
S10
S11
S12
S13
S14
S15
S16
Controlb
Controlc
a
b
c
The reaction was conducted in anoxic conditions. Dufulin was used as the control. Ningnanmycin was used as the control.
inhibitory effects (Table 2). The curative activities of S1 (45.3%),
The antibacterial activities of the title compounds (S1–S16)
S5 (45.9%), S11 (50.0%) and S16 (49.6%) against TMV were against rice bacterial leaf blight were evaluated by turbidimeter
similar to those of dufulin (46.3%), slightly lower than ning- tests.30 Bismerthiazol was used as the positive control.31 The
nanmycin (53.1%). The protective activities against TMV of S11 results showed that the title compounds displayed moderate to
(47.4%) and S16 (49.6%) were similar to those of dufulin good antibacterial activities (Table 3). Among them,
(49.4%), much less than ningnanmycin (63.4%). Moreover, the compounds S4, S7, S8 exhibited good in vitro antibacterial
activity of the title compound S8 is excess than those of the activity at concentrations of 200 and 100 mg mLꢁ1, which were
accordingly intermediates referring to the literature.20
slightly superior to bismerthiazol (82.3 and 57.8%, respectively).
Bioassay results indicated that the introduction of naph- Compounds S2, S6, S15 and S16 displayed moderate antibac-
thalene moiety to the dithioacetals can effectively improve the terial activity, compared to that of control. Other compounds
antiviral activity. In addition, among these compounds S1–S5, maintain low antibacterial activities. From the Table 3, SAR is
the R2 groups affect the antiviral activity (S1, S5 > S2, S3, S4), easier to summarize. When R1 ¼ H and 1-naphthalene-methoxy
with 1-naphthalene-methyl moiety at the para-position of at the 4-position, the order of activities (S1–S5) from high to low
dithioacetals in anti-TMV activity. The effect of the R2 groups in activity at 100 mg mLꢁ1 was hydroxyethyl (71.1%), 4-Cl–Ph–
anti-CMV activity is more obvious (S5 > S4 > S1 > S3 > S2). (57.0%), 4-F–Ph– (42.4%), 4-F5–Ph– (33.0%), propargyl (19.9%).
Compound S5 or S4 exhibited high activities when R2 is Different dithioacetal groups obviously affected the activities.
hydroxyethyl or propargyl moiety. To study the inuence of the When R1 was 3-CH3O and naphthalene-methoxy at 4-position,
R1 group, among these compounds S6–S9, its effect on activity is the order of activities (S6–S9) at 100 mg mLꢁ1 was hydroxyethyl
quite small with the CH3O group at the meta-position in anti- (71.7%), 4-F5–Ph– (70.6%), 4-F–Ph– (63.1%), propargyl (46.8%).
TMV activity. Nevertheless, compound S8 with the CH3O Among them, 3-CH3O group could increase the activity. When
group at the R1 position and the hydroxyethyl group showed R1 was H-group and naphthalene-methoxy at 3-position, the
good activity against CMV, further illustrate that the hydrox- order of activities (S10–S13) was hydroxyethyl (51.8%), 4-F–Ph–
yethyl group is favorable for activity (S4, S8 and S12) regardless (30.3%), 4-Cl–Ph– (25.6%), propargyl (22.8%). When R2 was
of naphthalene and R1 position on dithioacetals. To screen out selected for the hydroxyethyl group, the sequence activities of
high active compounds, the hydroxyethyl group was choosed to compounds were S15 (63.2%), S16 (57.1%), S14 (39.6%). The
change the R1 group and naphthalene position of the title above results further suggested that the dithioacetal hydrox-
compounds, the compound S16 exhibited best activity against yethyl group of the title compounds is critical for the activity
CMV and TMV. The results indicate that R1 and naphthalene and the R1 substituted and 1-naphthalene-methoxy of the
moiety is important for antiviral activities. Meanwhile, the derivatives inuenced the antibacterial activity.
hydroxyethyl group is indispensable for the antiviral activities of
these compounds.
To investigate the stability property of aromatic dithioace-
tals, compound S1 was selected to investigate in different
conditions. First, compound S1 was stable under the condition
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Table 3 Activities of the title compounds (S1–S16) against rice bacterial leaf blight
Inhibitiona (%)
Inhibitiona (%)
100 mg
Compd
200 mg mLꢁ1
100 mg mLꢁ1
Compd
200 mg mLꢁ1
mLꢁ1
S1
S2
S3
S4
S5
S6
S7
68.1 ꢂ 1.8
98.9 ꢂ 2.2
74.5 ꢂ 3.8
98.7 ꢂ 3.9
51.8 ꢂ 1.9
84.7 ꢂ 3.0
93.1 ꢂ 3.4
100.0 ꢂ 1.6
82.3 ꢂ 4.3
42.4 ꢂ 2.2
57.0 ꢂ 4.5
33.0 ꢂ 2.4
71.1 ꢂ 1.9
19.9 ꢂ 1.7
63.1 ꢂ 0.8
70.6 ꢂ 3.7
71.7 ꢂ 3.2
57.9 ꢂ 3.1
S9
66.2 ꢂ 3.5
79.2 ꢂ 2.6
49.8 ꢂ 1.3
90.0 ꢂ 3.7
50.0 ꢂ 0.5
69.1 ꢂ 4.6
98.9 ꢂ 3.9
93.3 ꢂ 3.4
46.8 ꢂ 5.8
30.3 ꢂ 5.2
25.6 ꢂ 5.4
51.8 ꢂ 3.8
22.8 ꢂ 6.6
39.6 ꢂ 5.0
63.2 ꢂ 4.5
57.1 ꢂ 1.1
S10
S11
S12
S13
S14
S15
S16
S8
Controlb
a
b
Average of three replicates. Bismerthiazol was used as the control.
of 0.1 M hydrochloric acid solution. Subsequently, compound chromatography on silica gel (EtOAc/hexane as eluent ¼ 1 : 20)
S1 was also stable in 0.1 M NaOH. The results indicated that affording the aromatic aldehydes (M1–M6).
aromatic dithioacetals acetals displayed much better stability
than acetals.
4-(Naphthalen-1-ylmethoxy)benzaldehyde (M1). White solid,
mp 122–123 ꢀC, yield 95%; 1H NMR (400 MHz, CDCl3) d 9.91 (s,
1H), 8.07–7.99 (m, 1H), 7.96–7.83 (m, 4H), 7.65–7.43 (m, 4H),
7.16 (d, J ¼ 8.7 Hz, 2H), 5.59 (s, 2H); 13C NMR (101 MHz, CDCl3)
d 190.77 (s), 163.80 (s), 133.83 (s), 132.04 (s), 131.40 (s), 131.27
(s), 130.27 (s), 129.42 (s), 128.84 (s), 126.77 (s), 126.68 (s), 126.09
(s), 125.30 (s), 123.43 (s), 115.21 (s), 68.95 (s).
Conclusions
In summary, a series of novel dithioacetals–naphthalene, total
sixteen compounds have been designed and synthesized with
moderate yields. Their structures have been fully conrmed.
Bioassay results showed that some compounds exhibited good
anti-CMV activities, antibacterial activity and moderate anti-
TMV activities in vivo. Among them, compound S16 in partic-
ularly showed the potent activity against CMV, TMV and good
antibacterial activity. Therefore, the basic motif of S16 can be
used as lead compound for further development.
3-Methoxy-4-(naphthalen-1-ylmethoxy)benzaldehyde
(M2).
White solid, mp 111–112 ꢀC, yield 94%; 1H NMR (400 MHz,
CDCl3) d 9.84 (s, 1H), 8.04 (d, J ¼ 8.0 Hz, 1H), 7.92–7.81 (m, 2H),
7.62–7.48 (m, 3H), 7.48–7.36 (m, 3H), 7.08 (d, J ¼ 8.2 Hz, 1H),
5.65 (s, 2H), 3.90 (s, 3H); 13C NMR (101 MHz, CDCl3) d 190.91 (s),
153.73 (s), 150.30 (s), 133.79 (s), 131.28 (s), 131.22 (s), 130.50 (s),
129.14 (s), 128.82 (s), 126.57 (s), 126.54 (s), 126.27 (s), 126.00 (s),
125.35 (s), 123.31 (s), 112.74 (s), 109.60 (s), 69.51 (s), 56.07 (s).
3-(Naphthalen-1-ylmethoxy)benzaldehyde (M3). White solid,
1
ꢀ
Experimental
General information
mp 95–96 C, yield 97%; H NMR (400 MHz, CDCl3) d 9.99 (s,
1H), 8.09–8.00 (m, 1H), 7.94–7.83 (m, 2H), 7.62–7.44 (m, 7H),
7.32–7.26 (m, 1H), 5.54 (s, 2H); 13C NMR (101 MHz, CDCl3)
d 192.07 (s), 159.41 (s), 137.91 (s), 133.83 (s), 131.67 (s), 131.51
(s), 130.20 (s), 129.30 (s), 128.78 (s), 126.78 (s), 126.60 (s), 126.03
(s), 125.32 (s), 123.82 (s), 123.60 (s), 122.30 (s), 113.32 (s), 68.94
(s).
All of the reagents were purchased from commercial suppliers
and used without further purication. All of the solvents were
used without further purication and drying before use. Thin-
layer chromatography with UV detection was conducted on
silica gel GF254. The melting points of the products were
determined with a WRX-4 microscopic melting point meter
(Shanghai Yice Apparatus & Equipment Co., Ltd., China) with
an uncorrected thermometer. 1H, and 13C nuclear magnetic
resonance (NMR) spectra were recorded on a Bruker Ascend-400
spectrometer (Bruker, Germany) in CDCl3 solution with tetra-
methylsilane as internal standard. High resolution mass spec-
tral (HRMS) data were determined with Thermo Scientic Q
Exactive (Thermo).
3-Chloro-4-(naphthalen-1-ylmethoxy)benzaldehyde (M4). Sandy
solid, mp 119–121 ꢀC, yield 96%; 1H NMR (400 MHz, CDCl3)
d 9.86 (s, 1H), 8.07 (d, J ¼ 8.1 Hz, 1H), 8.00–7.83 (m, 3H), 7.77
(dd, J ¼ 8.5, 2.0 Hz, 1H), 7.66 (d, J ¼ 6.8 Hz, 1H), 7.63–7.53 (m,
2H), 7.53–7.46 (m, 1H), 7.23 (d, J ¼ 8.5 Hz, 1H), 5.70 (s, 2H). 13
C
NMR (101 MHz, CDCl3) d 189.67 (s), 159.00 (s), 133.77 (s), 131.45
(s), 131.10 (s), 130.70 (s), 130.55 (s), 130.29 (s), 129.36 (s), 128.85
(s), 126.67 (s), 126.22 (s), 126.11 (s), 125.28 (s), 124.47 (s), 123.22
(s), 113.32 (s), 69.73 (s).
Preparation of aromatic aldehydes 1. Chloromethyl naph-
thalene (I, 10 mmol) was added to a vial containing acetonitrile
(40 mL), and hydroxyl substituted benzaldehyde (II, 10 mmol)
and potassium carbonate (10 mmol) were then added. Aer the
mixture was stirred and reuxed for 6 h, the solvent was
removed in vacuo. The residue was puried by column
2-Bromo-5-(naphthalen-1-ylmethoxy)benzaldehyde (M5). Red
solid, mp 129–131 ꢀC, yield 94%; 1H NMR (400 MHz, CDCl3)
d 10.35 (s, 1H), 8.06–7.99 (m, 1H), 7.95–7.86 (m, 2H), 7.65 (d, J ¼
3.2 Hz, 1H), 7.63–7.52 (m, 4H), 7.49 (dd, J ¼ 8.1, 7.2 Hz, 1H), 7.15
(dd, J ¼ 8.8, 3.2 Hz, 1H), 5.54 (s, 2H). 13C NMR (101 MHz, CDCl3)
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d 191.68 (s), 158.46 (s), 134.72 (s), 134.09 (s), 133.82 (s), 131.46
(s), 131.29 (s), 129.41 (s), 128.79 (s), 126.86 (s), 126.64 (s), 126.05
(s), 125.26 (s), 123.83 (s), 123.50 (s), 118.30 (s), 113.94 (s), 69.20
(s).
5-Methyl-2-(naphthalen-1-ylmethoxy)benzaldehyde (M6). White
solid, mp 114–116 ꢀC, yield 93%; 1H NMR (400 MHz, CDCl3)
d 10.43 (s, 1H), 8.06–8.02 (m, 1H), 7.96–7.82 (m, 2H), 7.67 (d, J ¼
2.1 Hz, 1H), 7.63–7.42 (m, 4H), 7.38 (dd, J ¼ 8.5, 2.3 Hz, 1H), 7.10
(d, J ¼ 8.5 Hz, 1H), 5.60 (s, 2H), 2.33 (s, 3H); 13C NMR (101 MHz,
CDCl3) d 189.88 (s), 159.26 (s), 136.52 (s), 133.81 (s), 131.60 (s),
131.40 (s), 130.62 (s), 129.30 (s), 128.84 (s), 128.47 (s), 126.67 (s),
126.53 (s), 126.06 (s), 125.26 (s), 125.12 (s), 123.36 (s), 113.24 (s),
69.38 (s), 20.30 (s).
Procedure for synthesis of dithioacetal derivatives (S1–S16).
Aromatic aldehyde (M, 1.0 mmol), thiols (1.0 mmol), 2.5 mol%
Brønsted acidic ionic liquid were added to 1.0 mL of dichloro-
methane. The mixture was stirring at 40 ꢀC for 3 h. The resulting
mixture was concentrated under reduced pressure to give crude
product. 5 mL water was added to the crude product and
continues to stirring for 0.5 h. Then the water with ionic liquid
was removed. Finally, the crude product was puried by column
chromatography using hexane/EtOAc (1 : 2, v/v) or recrystalli-
zation with alcohol.
Bis(4-uorophenyl)-4-(naphthalen-1-ylmethoxy)-phenyl-
dithioacetal (S1). White solid, mp 103–105 ꢀC, yield 96%; 1H
NMR (400 MHz, CDCl3) d 8.05 (d, J ¼ 7.4 Hz, 1H), 7.95–7.86 (m,
2H), 7.61–7.47 (m, 4H), 7.37–7.29 (m, 4H), 7.24 (d, J ¼ 8.6 Hz,
2H), 7.01–6.91 (m, 6H), 5.49 (s, 2H), 5.26 (s, 1H); 13C NMR (101
MHz, CDCl3) d 164.08 (s), 161.61 (s), 158.62 (s), 135.71 (d, J ¼ 8.4
Hz), 133.80 (s), 132.05 (s), 131.72 (s), 131.49 (s), 129.30 (s),
129.11 (s), 128.75 (s), 126.57 (d, J ¼ 12.3 Hz), 125.97 (s), 125.30
(s), 123.64 (s), 116.07 (s), 115.85 (s), 114.87 (s), 68.72 (s), 61.55
(s); IR (KBr, cmꢁ1) n 1604.8 (s), 1584.1 (s), 1509.1 (s), 1487.6 (s),
1244.6 (s), 1222.7 (s); HRMS (ES) m/z for C30H22F2OS2 [M + Na]+
cacld 523.0972, found 523.0978.
Bis(4-chlorophenyl)-4-(naphthalen-1-ylmethoxy)-phenyl-
dithioacetal (S2). White solid, mp 113–114 ꢀC, yield 92%; 1H
NMR (400 MHz, CDCl3) d 8.09–8.02 (m, 1H), 7.96–7.85 (m, 2H),
7.62–7.47 (m, 4H), 7.34–7.20 (m, 10H), 6.98 (d, J ¼ 8.7 Hz, 2H),
5.49 (s, 2H), 5.36 (s, 1H); 13C NMR (101 MHz, CDCl3) d 158.75 (s),
134.21 (s), 134.07 (s), 133.80 (s), 132.72 (s), 132.02 (s), 131.50 (s),
131.28 (s), 129.15 (s), 129.04 (s), 128.75 (s), 126.66 (s), 126.52 (s),
125.98 (s), 125.31 (s), 123.64 (s), 114.99 (s), 68.75 (s), 60.21 (s); IR
(KBr, cmꢁ1) n 1505.4 (s), 1471.6 (s), 1233.5 (s), 1091.4 (s), 1005.4
(s); HRMS (ES) m/z for C30H22Cl2OS2 [M + Na]+ cacld 555.0381,
found 555.0384.
Bis(pentauorophenyl)-4-(naphthalen-1-ylmethoxy)-phenyl-
dithioacetal (S3). White solid, mp 137–139 ꢀC, yield 83%; 1H
NMR (400 MHz, CDCl3) d 8.05–7.98 (m, 1H), 7.95–7.83 (m, 2H),
7.62–7.51 (m, 3H), 7.50–7.44 (m, 1H), 7.41 (d, J ¼ 8.7 Hz, 2H),
6.98 (d, J ¼ 8.7 Hz, 2H), 5.66 (s, 1H), 5.48 (s, 2H); 13C NMR (101
MHz, CDCl3) d 159.67 (s), 133.79 (s), 131.73 (s), 131.43 (s), 129.20
(s), 128.76 (s), 129.11 (s), 128.46 (s), 126.64 (s), 126.55 (s), 125.99
(s), 125.27 (s), 123.52 (s), 115.24 (s), 68.76 (s), 57.63 (s); IR
(KBr, cmꢁ1) n 1513.8 (s), 1487.9 (s), 1230.5 (s), 1098.2 (s); HRMS
(ES) m/z for C30H14F10OS2 [M + Na]+ cacld 667.0219, found
667.0216.
Bis(2-hydroxyethyl)-4-(naphthalen-1-ylmethoxy)-phenyl-
dithioacetal (S4). White solid, mp 105–107 ꢀC, yield 94%; 1H
NMR (400 MHz, CDCl3) d 8.08–8.01 (m, 1H), 7.93–7.84 (m, 2H),
7.61–7.45 (m, 4H), 7.44–7.37 (m, 2H), 7.07–6.99 (m, 2H), 5.49 (s,
2H), 5.07 (s, 1H), 3.74 (t, J ¼ 5.5 Hz, 4H), 2.86 (dt, J ¼ 14.0,
5.8 Hz, 2H), 2.73 (dt, J ¼ 14.0, 5.9 Hz, 2H), 2.17 (s, 2H); 13C NMR
(101 MHz, CDCl3) d 158.77 (s), 133.81 (s), 132.34 (s), 132.07 (s),
131.52 (s), 129.12 (s), 128.94 (s), 128.72 (s), 126.65 (s), 126.50 (s),
125.95 (s), 125.30 (s), 123.65 (s), 115.13 (s), 68.80 (s), 61.31 (s),
52.68 (s), 35.66 (s); IR (KBr, cmꢁ1) n 3477.8 (s), 3414.4 (s), 1617.8
(s), 1510.5 (s), 1238.2 (s); HRMS (ES) m/z for C22H24O3S2 [M +
Na]+ cacld 423.1059, found 423.1064.
Bis(propenyl)-4-(naphthalen-1-ylmethoxy)-phenyl-dithioacetal
(S5). White solid, mp 114–116 ꢀC, yield 97%; 1H NMR (400 MHz,
CDCl3) d 8.07–8.01 (m, 1H), 7.92–7.83 (m, 2H), 7.59 (d, J ¼
6.8 Hz, 1H), 7.57–7.49 (m, 2H), 7.49–7.43 (m, 1H), 7.38 (t, J ¼
5.8 Hz, 2H), 7.01 (d, J ¼ 8.7 Hz, 2H), 5.80 (ddt, J ¼ 17.1, 10.0,
7.2 Hz, 2H), 5.48 (s, 2H), 5.18–5.06 (m, 4H), 4.77 (s, 1H), 3.27
(dd, J ¼ 13.7, 7.2 Hz, 2H), 3.06 (dd, J ¼ 13.7, 7.2 Hz, 2H); 13C
NMR (101 MHz, CDCl3) d 158.54 (s), 133.89 (s), 133.82 (s), 132.33
(s), 132.20 (s), 131.55 (s), 129.30 (s), 129.08 (s), 128.72 (s), 126.65
(s), 126.48 (s), 125.94 (s), 125.32 (s), 123.70 (s), 117.52 (s), 114.95
(s), 68.77 (s), 49.99 (s), 35.28 (s); IR (KBr, cmꢁ1) n 3351.2 (s),
2123.6 (s), 1537.4 (s), 1432.1 (s), 1218.6 (s); HRMS (ES) m/z for
C
24H24OS2 [M + Na]+ cacld 437.1216, found 437.1219.
Bis(4-uorophenyl)-4-(naphthalen-1-yl-methoxy)-3-
methoxylphenyldithioacetal (S6). White solid, mp 117–119 ꢀC,
yield 92%; 1H NMR (400 MHz, CDCl3) d 8.09 (d, J ¼ 8.0 Hz, 1H),
7.92–7.79 (m, 2H), 7.60–7.40 (m, 4H), 7.36–7.27 (m, 4H), 6.99–
6.89 (m, 4H), 6.87 (d, J ¼ 2.0 Hz, 1H), 6.81 (d, J ¼ 8.3 Hz, 1H),
6.68 (dd, J ¼ 8.2, 2.1 Hz, 1H), 5.55 (s, 2H), 5.19 (s, 1H), 3.80 (s,
3H); 13C NMR (101 MHz, CDCl3) d 164.12 (s), 161.65 (s), 149.92
(s), 148.06 (s), 135.80 (d, J ¼ 8.5 Hz), 133.75 (s), 132.54 (s), 132.21
(s), 131.37 (s), 129.16 (d, J ¼ 3.4 Hz), 128.77 (d, J ¼ 13.2 Hz),
126.31 (d, J ¼ 13.6 Hz), 125.86 (s), 125.30 (s), 123.57 (s), 120.29
(s), 116.06 (s), 115.84 (s), 114.15 (s), 111.46 (s), 69.76 (s), 61.82
(s), 56.02 (s); IR (KBr, cmꢁ1) n 1588.4 (s), 1510.1 (s), 1486.9 (s),
1466.3 (s), 1265.5 (s), 1227.3 (s), 1136.0 (s); HRMS (ES) m/z for
C
31H24F2O2S2 [M + H]+ cacld 531.1259, found 531.1257.
Bis(pentauorophenyl)-4-(naphthalen-1-ylmethoxy)-3-
methoxylphenyldithioacetal (S7). White solid, mp 118–120 ꢀC,
yield 85%; 1H NMR (400 MHz, CDCl3) d 8.05 (d, J ¼ 7.9 Hz, 1H),
7.91–7.82 (m, 2H), 7.58–7.50 (m, 3H), 7.46–7.42 (m, 1H), 7.11 (s,
1H), 6.83 (s, 2H), 5.64 (s, 1H), 5.54 (s, 2H), 3.88 (s, 3H). 13C NMR
(101 MHz, CDCl3) d 150.23 (s), 149.20 (s), 133.74 (s), 131.84 (s),
131.29 (s), 129.06 (s), 128.92 (s), 128.72 (s), 126.42 (s), 126.21 (s),
125.89 (s), 125.27 (s), 123.43 (s), 120.47 (s), 113.97 (s), 110.90 (s),
69.66 (s), 57.91 (s), 56.10 (s); IR (KBr, cmꢁ1) n 1514.3 (s), 1489.8
(s), 1236.1 (s), 1088.2 (s); HRMS (ES) m/z for C31H16F10O2S2 [M +
Na]+ cacld 697.0324, found 697.0321.
Bis(2-hydroxyethyl)-4-(naphthalen-1-ylmethoxy)-3-
methoxylphenyldithioacetal (S8). White solid, mp 113–114 ꢀC,
yield 93%; 1H NMR (400 MHz, CDCl3) d 8.10 (d, J ¼ 8.1 Hz, 1H),
7.91–7.87 (m, 1H), 7.83 (d, J ¼ 8.3 Hz, 1H), 7.59 (d, J ¼ 6.8 Hz,
1H), 7.53 (td, J ¼ 7.7, 1.4 Hz, 2H), 7.47–7.42 (m, 1H), 7.07 (s, 1H),
6.91 (s, 2H), 5.56 (s, 2H), 5.03 (s, 1H), 3.89 (s, 3H), 3.74 (t, J ¼
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5.8 Hz, 4H), 2.84 (dt, J ¼ 14.0, 5.8 Hz, 2H), 2.72 (dt, J ¼ 14.0, (s), 1514.8 (s), 1464.7 (s), 1011.2 (s); HRMS (ES) m/z for
5.9 Hz, 2H), 2.18 (s, 2H); 13C NMR (101 MHz, CDCl3) d 150.33 (s),
C
22H24O3S2 [M + Na]+ cacld 423.1059, found 423.1062.
148.34 (s), 133.76 (s), 133.18 (s), 132.24 (s), 131.39 (s), 128.83 (s),
Bis(propenyl)-3-(naphthalen-1-ylmethoxy)-phenyl-dithioacetal
128.67 (s), 126.36 (s), 126.28 (s), 125.84 (s), 125.32 (s), 123.58 (s), (S13). White solid, mp 91–93 ꢀC, yield 96%; 1H NMR (400 MHz,
120.08 (s), 114.18 (s), 111.34 (s), 69.84 (s), 61.34 (s), 56.15 (s), CDCl3) d 8.08 (d, J ¼ 7.8 Hz, 1H), 7.95–7.81 (m, 2H), 7.65–7.44
53.09 (s), 35.72 (s); IR (KBr, cmꢁ1) n 3414.5 (s), 32.46.4 (s), 1508.7 (m, 4H), 7.32–7.26 (m, 1H), 7.17 (d, J ¼ 1.8 Hz, 1H), 7.05 (d, J ¼
(s), 1466.4 (s), 1259.1 (s), 1212.0 (s), 1141.1 (s), 1004.7 (s); HRMS 7.6 Hz, 1H), 6.97 (dd, J ¼ 7.9, 2.1 Hz, 1H), 5.80 (ddt, J ¼ 17.1,
(ES) m/z for C23H26O4S2 [M + Na]+ cacld 453.1165, found 10.0, 7.2 Hz, 2H), 5.51 (s, 2H), 5.21–5.00 (m, 4H), 4.76 (s, 1H),
453.1161.
Bis(propenyl)-4-(naphthalen-1-ylmethoxy)-3-methoxyl-
3.28 (dd, J ¼ 13.7, 7.2 Hz, 2H), 3.07 (dd, J ¼ 13.7, 7.2 Hz, 2H); 13
C
NMR (101 MHz, CDCl3) d 159.05 (s), 141.61 (s), 133.81 (s), 133.78
phenyldithioacetal (S9). Yellow solid, mp 90–92 ꢀC, yield 95%; 1H (s), 132.21 (s), 131.58 (s), 129.64 (s), 129.07 (s), 128.69 (s), 126.75
NMR (400 MHz, CDCl3) d 8.10 (d, J ¼ 8.1 Hz, 1H), 7.92–7.79 (m, (s), 126.47 (s), 125.92 (s), 125.30 (s), 123.78 (s), 120.84 (s), 117.64
2H), 7.63–7.40 (m, 4H), 7.06 (d, J ¼ 1.8 Hz, 1H), 6.94–6.83 (m, (s), 114.62 (s), 114.50 (s), 68.71 (s), 50.48 (s), 35.31 (s); IR
2H), 5.79 (ddt, J ¼ 17.1, 10.0, 7.2 Hz, 2H), 5.56 (s, 2H), 5.17–5.04 (KBr, cmꢁ1) n 3321.2 (s), 2123.4 (s), 1551.4 (s), 1458.1 (s), 1208.9
(m, 4H), 4.73 (s, 1H), 3.88 (s, 3H), 3.27 (dd, J ¼ 13.7, 7.1 Hz, 2H), (s); HRMS (ES) m/z for C24H24OS2 [M + Na]+ cacld 415.1161,
3.06 (dd, J ¼ 13.7, 7.2 Hz, 2H). 13C NMR (101 MHz, CDCl3) found 415.1166.
d 150.17 (s), 148.06 (s), 133.87 (s), 133.76 (s), 133.18 (s), 132.37
Bis(2-hydroxyethyl)-5-(naphthalen-1-ylmethoxy)-2-bromo-
ꢀ
(s), 131.40 (s), 128.78 (s), 128.67 (s), 126.34 (s), 126.26 (s), 125.82 phenyldithioacetal (S14). Red solid, mp 123–124 C, yield 93%;
(s), 125.35 (s), 123.62 (s), 120.40 (s), 117.54 (s), 114.15 (s), 111.72 1H NMR (400 MHz, CDCl3) d 8.06 (d, J ¼ 7.9 Hz, 1H), 7.88 (dd, J
(s), 69.84 (s), 56.09 (s), 50.41 (s), 35.34 (s); IR (KBr, cmꢁ1) n ¼ 13.8, 8.2 Hz, 2H), 7.68–7.38 (m, 6H), 6.85 (dd, J ¼ 8.8, 2.7 Hz,
3331.2 (s), 2118.4 (s), 1557.4 (s), 1462.1 (s), 1208.9 (s); HRMS (ES) 1H), 5.51 (s, 3H), 3.76 (t, J ¼ 5.1 Hz, 4H), 2.90–2.79 (m, 2H), 2.79–
m/z for C25H26O2S2 [M + Na]+ cacld 445.1266, found 445.1269.
Bis(4-uorophenyl)-3-(naphthalen-1-ylmethoxy)-phenyl-
2.60 (m, 2H), 2.16 (s, 2H); 13C NMR (101 MHz, CDCl3) d 158.67
(s), 140.15 (s), 133.81 (s), 133.54 (s), 131.65 (s), 131.49 (s), 129.26
1
ꢀ
dithioacetal (S10). White solid, mp 105–106 C, yield 92%; H (s), 128.75 (s), 126.91 (s), 126.60 (s), 126.02 (s), 125.25 (s), 123.65
NMR (400 MHz, CDCl3) d 8.03 (d, J ¼ 7.8 Hz, 1H), 7.94–7.84 (m, (s), 117.12 (s), 115.85 (s), 114.05 (s), 69.06 (s), 61.09 (s), 51.53 (s),
2H), 7.61–7.51 (m, 3H), 7.49–7.45 (m, 1H), 7.35–7.28 (m, 4H), 36.01 (s); IR (KBr, cmꢁ1) n 3415.1 (s), 3291.4 (s), 1517.8 (s),
7.18 (t, J ¼ 7.9 Hz, 1H), 7.00–6.86 (m, 7H), 5.43 (s, 2H), 5.21 (s, 1467.1 (s), 1016.2 (s); HRMS (ES) m/z for C22H23BrO3S2 [M + Na]+
1H); 13C NMR (101 MHz, CDCl3) d 164.15 (s), 161.68 (s), 158.82 cacld 501.0164, found 501.0161.
(s), 140.85 (s), 135.81 (d, J ¼ 8.2 Hz), 133.82 (s), 132.10 (s), 131.52
Bis(2-hydroxyethyl)-4-(naphthalen-1-ylmethoxy)-3-chloro-
(s), 129.55 (s), 129.08 (s), 128.71 (s), 126.57 (d, J ¼ 18.1 Hz), phenyldithioacetal (S15). White solid, mp 102–104 ꢀC, yield 94%;
125.95 (s), 125.28 (s), 123.66 (s), 120.61 (s), 116.05 (s), 115.84 (s), 1H NMR (400 MHz, CDCl3) d 8.08 (d, J ¼ 8.2 Hz, 1H), 7.94–7.82
115.01 (s), 114.26 (s), 68.71 (s), 62.01 (s); IR (KBr, cmꢁ1) n 1643.2 (m, 2H), 7.65 (d, J ¼ 6.9 Hz, 1H), 7.61–7.43 (m, 4H), 7.31 (dd, J ¼
(s), 1593.7 (s), 1488.9 (s), 1212.1 (s); HRMS (ES) m/z for 8.5, 2.3 Hz, 1H), 7.05 (d, J ¼ 8.5 Hz, 1H), 5.59 (s, 2H), 5.04 (s, 1H),
C
30H22F2OS2 [M + Na]+ cacld 523.0972, found 523.0977.
3.76 (q, J ¼ 5.6 Hz, 4H), 2.85 (dt, J ¼ 14.0, 5.8 Hz, 2H), 2.71 (dt, J
Bis(4-chlorophenyl)-3-(naphthalen-1-ylmethoxy)-phenyl-
¼ 14.0, 5.9 Hz, 2H), 2.15 (s, 2H); 13C NMR (101 MHz, CDCl3)
1
ꢀ
dithioacetal (S11). White solid, mp 119–121 C, yield 91%; H d 154.10 (s), 133.74 (s), 133.63 (s), 131.55 (s), 131.23 (s), 129.71
NMR (400 MHz, CDCl3) d 8.04 (d, J ¼ 8.1 Hz, 1H), 7.97–7.84 (m, (s), 129.05 (s), 128.74 (s), 126.98 (s), 126.49 (s), 126.16 (s), 125.96
2H), 7.66–7.52 (m, 3H), 7.51–7.44 (m, 1H), 7.36–7.18 (m, 9H), (s), 125.31 (s), 123.69 (s), 123.44 (s), 114.08 (s), 69.68 (s), 61.47
7.06–7.01 (m, 1H), 7.00–6.90 (m, 2H), 5.45 (s, 2H), 5.32 (s, 1H); (s), 52.25 (s), 35.59 (s); IR (KBr, cmꢁ1) n 3418.8 (s), 3271.4 (s),
13C NMR (101 MHz, CDCl3) d 158.91 (s), 140.47 (s), 134.63 (s), 1537.8 (s), 1467.1 (s), 1016.2 (s); HRMS (ES) m/z for
134.22 (s), 133.81 (s), 132.51 (s), 132.05 (s), 131.51 (s), 129.68 (s),
129.08 (s), 129.04 (s), 128.72 (s), 126.66 (s), 126.51 (s), 125.95 (s),
C
22H23ClO3S2 [M + Na]+ cacld 457.0669, found 457.0663.
Bis(2-hydroxyethyl)-2-(naphthalen-1-ylmethoxy)-5-methyl-
125.29 (s), 123.65 (s), 120.60 (s), 115.19 (s), 114.26 (s), 68.72 (s), phenyldithioacetal (S16). White solid, mp 139–140 ꢀC, yield 91%;
60.76 (s); IR (KBr, cmꢁ1) n 1544.6 (s), 1491.6 (s), 1230.5 (s), 1H NMR (400 MHz, CDCl3) d 8.11–8.03 (m, 1H), 7.97–7.82 (m,
1081.4 (s); HRMS (ES) m/z for C30H22Cl2OS2 [M + Na]+ cacld 2H), 7.63–7.40 (m, 5H), 7.12–7.04 (m, 1H), 7.00 (d, J ¼ 8.3 Hz,
555.0381, found 555.0376.
Bis(2-hydroxyethyl)-3-(naphthalen-1-ylmethoxy)-phenyl-
1H), 5.52 (s, 2H), 5.43 (s, 1H), 3.48 (q, J ¼ 5.9 Hz, 4H), 2.67 (dd, J
¼ 12.8, 7.0 Hz, 2H), 2.57 (dd, J ¼ 12.9, 7.1 Hz, 2H), 2.32 (s, 3H),
dithioacetal (S12). White solid, mp 101–103 C, yield 94%; H 1.90 (d, J ¼ 6.2 Hz, 2H); 13C NMR (101 MHz, CDCl3) d 152.77 (s),
NMR (400 MHz, CDCl3) d 8.07 (d, J ¼ 7.9 Hz, 1H), 7.97–7.81 (m, 133.83 (s), 132.16 (s), 131.57 (s), 131.06 (s), 129.63 (s), 129.28 (s),
2H), 7.67–7.42 (m, 4H), 7.34–7.26 (m, 1H), 7.21–7.14 (m, 1H), 129.14 (s), 128.85 (s), 128.78 (s), 126.91 (s), 126.52 (s), 126.03 (s),
7.07 (d, J ¼ 7.7 Hz, 1H), 6.98 (dd, J ¼ 8.0, 2.1 Hz, 1H), 5.51 (s, 125.37 (s), 123.69 (s), 112.24 (s), 69.38 (s), 60.93 (s), 45.21 (s),
2H), 5.04 (s, 1H), 3.73 (s, 4H), 2.84 (dt, J ¼ 14.0, 5.8 Hz, 2H), 2.72 36.05 (s), 20.64 (s); IR (KBr, cmꢁ1) n 3421.2 (s), 3271.4 (s), 1547.6
(dt, J ¼ 14.0, 5.9 Hz, 2H), 2.10 (s, 2H); 13C NMR (101 MHz, (s), 1477.3 (s), 1018.2 (s); HRMS (ES) m/z for C23H26O3S2 [M +
CDCl3) d 159.11 (s), 141.65 (s), 133.81 (s), 132.10 (s), 131.54 (s), Na]+ cacld 437.1216, found 437.1219.
129.86 (s), 129.08 (s), 128.70 (s), 126.72 (s), 126.50 (s), 125.95 (s),
1
ꢀ
125.27 (s), 123.70 (s), 120.40 (s), 114.94 (s), 114.24 (s), 68.76 (s),
61.30 (s), 53.17 (s), 35.70 (s); IR (KBr, cmꢁ1) n 3415.1 (s), 3282.6
32380 | RSC Adv., 2019, 9, 32375–32381
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RSC Advances
9 J. D. Jones and J. L. Dangl, Nature, 2006, 444, 323.
Biological assays
10 F. P. Silverman, P. D. Petracek, Z. Ju, C. M. Fledderman,
D. F. Heiman and P. Warrior, J. Agric. Food Chem., 2005,
53, 9764.
11 H. Kauss, K. Krause and W. Jeblick, Biochem. Biophys. Res.
Commun., 1992, 189, 304.
12 Z. J. Fan, Z. G. Shi, H. K. Zhang, X. F. Liu, L. L. Bao, L. Ma,
X. Zuo, Q. X. Zheng and N. Mi, J. Agric. Food Chem., 2009,
57, 4279.
13 F. P. Silverman, P. D. Petracek, Z. Ju, C. M. Fledderman,
D. F. Heiman and P. Warrior, J. Agric. Food Chem., 2005,
53, 9769.
In vivo antiviral activity. The biological activity of the title
compounds against tobacco mosaic virus (TMV) and cucumber
mosaic virus (CMV) respectively were evaluated using a half-leaf
method according to the previously references.24 Virus puri-
cation and activity evaluation of the compounds were per-
formed as previously reported.27,28
In vitro antibacterial activity. The antibacterial activities
against rice bacterial leaf blight of title products were evaluated
via the turbid meter test according to the reported method.29
Bacterial cultivation and activity test of the title compounds
were performed as previously reported.30
14 F. P. Silverman, P. D. Petracek, D. F. Heiman,
C. M. Fledderman and P. Warrior, J. Agric. Food Chem.,
2005, 53, 9775.
Conflicts of interest
15 M. Lhassani, O. Chavignon, J. M. Chezal, J. C. Teulade,
J. P. Chapat, R. Snoeck, G. Andrei, J. Balzarini, E. D. De
Clercq and A. Gueiffier, Eur. J. Med. Chem., 1999, 34, 271.
16 L. Sakthikumar, J. Kavitha and R. Mahalakshmi, Der Pharma
Chem., 2014, 6, 294.
The authors conrm that this article content has no conict of
interest.
Acknowledgements
17 H. Koga, Y. Tsuji, K. Inoue, K. Kanai, T. Majima, T. Kasai,
K. Uchida and H. Yamaguchi, J. Infect. Chemother., 2006,
12, 163.
18 H. Koga, Y. Nanjoh, K. Makimura and R. Tsuboi, Med.
Mycol., 2009, 47, 640.
19 S. Pandey, S. Suryawanshi, S. Gupta and V. Srivastava, Eur. J.
Med. Chem., 2005, 40, 751.
20 J. Zhang, L. Zhao, C. Zhu, Z. X. Wu, G. P. Zhang, X. H. Gan,
D. Y. Liu, J. K. Pan, D. Y. Hu and B. A. Song, J. Agric. Food
Chem., 2017, 65, 4582.
The authors gratefully acknowledge nancial support by the
National Key Research and Development Program of China (No.
2017YFD0200506), the National Natural Science Foundation of
China (No. 21807037), the National Special Fund For Agro-
Scientic Research in the Public Interest of China (No.
201503112-8), the Provincial Major Project of Education
Department in Anhui (No. KJ2018A0386), the Provincial Major
Project of Excellent Youth Talent Support Program in Anhui
(No. gxyqZD2018092), National innovation training program for
college students (20171402085). We also sincerely thank all co-
workers who have contributed to the work.
21 J. Chen, J. Shi, L. Yu, D. Y. Liu, X. H. Gan, B. A. Song and
D. Y. Hu, J. Agric. Food Chem., 2018, 66, 5335.
22 H. C. Zhang and X. L. Li, Instruction manual for plant growth
regulators, China Agriculture Press, 2011.
Notes and references
23 K. K. Pasunooti, H. Chai, C. N. Jensen, B. K. Gorityala,
S. Wang and X. W. Liu, Tetrahedron Lett., 2011, 52, 80.
24 Z. W. Wang, A. Feng, M. Cui, Y. Liu, L. Wang and
Q. M. Wang, PLoS One, 2012, 7, e52933.
1 (a) J. A. Tomlinson, Ann. Appl. Biol., 1987, 110, 661; (b)
A. N. Creager, K. B. Scholthof, V. Citovsky and
H. B. Scholthof, Plant Cell, 1999, 11, 301; (c)
M. Jacquemond, Adv. Virus Res., 2012, 84, 439.
25 S. G. Bhansali, et al., Int. J. PharmTech Res., 2013, 5, 1224.
26 G. V. Gooding Jr and T. T. Hebert, Phytopathology, 1967, 57,
1285.
27 H. Scott, Virology, 1963, 20, 103.
28 D. G. Zhou, D. D. Xie, F. C. He, B. A. Song and D. Y. Hu,
Bioorg. Med. Chem. Lett., 2018, 28, 2091.
29 Z. X. Wu, J. Zhang, J. X. Chen, J. K. Pan, L. Zhao, D. Y. Liu,
A. W. Zhang, J. Chen, D. Y. Hu and B. A. Song, Pest
Manage. Sci., 2017, 73, 2079.
`
2 (a) S. Boquel, J. Zhang, C. Goyer, M. A. Giguere, C. Clark and
Y. Pelletier, Pest Manage. Sci., 2015, 71, 1106; (b) A. V. Karasev
and S. M. Gray, Annu. Rev. Phytopathol., 2013, 51, 571.
3 K. B. G. Scholthof, S. Adkins, H. Czosnek, P. Palukaitis,
E. Jacquot, T. Hohn, B. Hohn, K. Saunders, T. Candresse,
P. Ahlquist, C. Hemenway and G. D. Foster, Mol. Plant
Pathol., 2011, 12, 938.
4 H. Xiao, P. Li, D. Y. Hu and B. A. Song, Bioorg. Med. Chem.
Lett., 2014, 24, 3452.
30 (a) Z. H. Ma, M. G. Zhou and Z. Y. Ye, Acta Phytopathol. Sin.,
1997, 27, 237; (b) G. B. Shen and M. G. Zhou, Plant Prot.,
2002, 28, 9.
31 P. Li, D. Y. Hu, D. D. Xie, J. X. Chen, L. H. Jin and B. A. Song,
J. Agric. Food Chem., 2018, 66, 3093.
5 M. H. Chen, P. Li, D. Y. Hu and B. A. Song, Bioorg. Med. Chem.
Lett., 2016, 26, 168.
6 J. Wu and B. A. Song, Sci. Sin.: Chim., 2016, 46, 1165.
7 B. A. Song, S. Yang, L. H. Jin and P. S. Bhadury, Environment
friendly antiviral agents for plants, Springer, Berlin, 2009.
8 Z. Z. Wang, D. D. Xie, X. H. Gan, D. Y. Hu and B. A. Song,
Bioorg. Med. Chem. Lett., 2017, 27, 4096.
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RSC Adv., 2019, 9, 32375–32381 | 32381