Discovery of N-Aryl-pyridine-4-ones as Novel Potential Agrochemical Fungicides and Bactericides

Article abstract of DOI:10.1021/acs.jafc.9b06296

A series of N-aryl-pyridine-4-one derivatives were designed and synthesized using maltol and antidesmone as lead compounds, and then their fungicidal/bactericidal activities and possible mechanism of action against Colletotrichum musae were explored. Most of these compounds exhibited significant fungicidal activity in vitro. Especially, compound 23 has more than 90% inhibitory activity against nine plant pathogenic fungi at 50 μg mL^-1, which is superior to azoxystrobin. Moreover, an in vivo bioassay also demonstrated that compound 23 exhibited high-efficiency broad-spectrum antifungal activity and can effectively control postharvest diseases of mango. In addition, it was found that compounds 22 and 23 can also effectively control rice bacterial leaf blight in pot experiments, which was even more effective than zhongshengmycin. Preliminary mechanism studies revealed that compound 23 may cause cell membrane and mitochondria destruction. These findings indicate that compound 23 can be used to develop potential agrochemical fungicides and bactericides.

Full text of DOI:10.1021/acs.jafc.9b06296

Subscriber access provided by University of Winnipeg Library
Agricultural and Environmental Chemistry
Discovery of N-aryl-pyridine-4-ones as Novel
Potential Agrochemical Fungicides and Bactericides
Xiuqiang Yu, Xinyue Zhu, Yang Zhou, Qinglin Li, Zhan Hu, Ting Li,
Jun Tao, Menglan Dou, Meng Zhang, Yu Shao, and Ranfeng Sun
J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.9b06296 • Publication Date (Web): 25 Nov 2019
Downloaded from pubs.acs.org on November 27, 2019
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the
course of their duties.

Page 1 of 37
Journal of Agricultural and Food Chemistry
1
2
3
Discovery of N-aryl-pyridine-4-ones as Novel
Potential Agrochemical Fungicides and
Bactericides
4
5
Xiuqiang Yu,1,# Xinyue Zhu,1,# Yang Zhou,1 Qinglin Li,1 Zhan Hu,1 Ting Li,3 Jun Tao,3
Menglan Dou,1 Meng Zhang,1 Yu Shao,2 and Ranfeng Sun*,1
1
6
7
8
Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and
Pests, Ministry of Education, College of Plant Protection, Hainan University, Haikou,
570228, People’s Republic of China
9
2 Danzhou Tobacco Company, Hainan Provincial Branch of CNTC, Danzhou, 571700,
People’s Republic of China
10
11
12
3 Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou,
570228, People’s Republic of China
13
14
15
16
17
18
19
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 2 of 37
20
21
*To whom correspondence should be addressed. Telephone/Fax: +86-898-66192906; E-mail:
srf18@hainanu.edu.cn.
22
#These authors contributed equally to this work.
ACS Paragon Plus Environment

Page 3 of 37
Journal of Agricultural and Food Chemistry
24
ABSTRACT
25
26
27
28
29
30
31
32
33
34
35
36
A series of N-aryl-pyridine-4-ones derivatives were designed and synthesized by using maltol and
antidesmone as lead compounds, and then their fungicidal/bactericidal activities and possible
mechanism of action against Colletotrichum musae were explored. Most of these compounds
exhibited significant fungicidal activity in vitro. Especially, compound 23 has more than 90%
inhibitory activity against 9 plant pathogenic fungi at 50 μg mL-1, which is superior to azoxystrobin.
Moreover, in vivo bioassay also demonstrated that compound 23 exhibited high-efficiency broad-
spectrum antifungal activity and can effectively control postharvest diseases of mango. In addition,
it was found that compounds 22 and 23 can also effectively control rice bacterial leaf blight in pot
experiments, which was even more effective than zhongshengmycin. Preliminary mechanism
studies revealed that compound 23 maybe cause cell membrane and mitochondria destruction. These
findings indicate that compound 23 can be used to develop potential agrochemical fungicides and
bactericides.
37
38
39
KEYWORDS: maltol, N-aryl-pyridine-4-ones, fungicidal activity, bactericidal activity,
postharvest diseases, action mechanism
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 4 of 37
40
INTRODUCTION
41
42
43
44
45
46
47
48
49
Plant diseases pose a serious threat to the safety and stability of crop production. In plant
diseases, most of the diseases are caused by pathogenic fungi1 and bacteria infection2. A variety of
chemical fungicides and antibiotics are used to reduce plant diseases in agriculture. However, some
fungicides and bactericides have caused environmental pollutions3-4, pesticide residues in
agricultural products5-7, at the same time, resistant plant-pathogenic fungi8 and bacteria9 isolates
have been reported around the world, such as azoxystrobin-resistant isolates10-14 and streptomycin-
resistant isolates15-17. These problems have promoted pesticide researchers to find broad-spectrum,
high-effective and low-risk fungicides and bactericides with no cross-resistance to current
commercial products.
50
51
52
53
54
55
56
57
58
59
60
61
It is well known that using natural products as lead compounds is an effective method for the
discovery of pesticides. Antidesmone (Figure 1) is an antifungal quinoline alkaloids isolated from
Waltheria indica in our lab and exhibited broad-spectrum antifungal activities against
phytopathogenic fungi18. Maltol (3-hydroxy-2-methyl-4-pyrone, Figure 1) is a natural flavor which
is widely used as a food additive and a potent antioxidative agent19. At the same time, it has been
reported that maltol and its derivatives have certain antifungal and antibacterial activity20-21. In order
to identify the pharmacophore and simplify the structure of antidesmone, a series of N-substituted-
pyridine-4-ones (compounds 6-38) were designed and synthesized based on the chemical structure
of antidesmone and maltol (Figure 1, Scheme 1). Furthermore, in vitro and in vivo antifungal and
antibacterial activity of compounds 6-38 were evaluated and the structure-activity relationship was
also discussed. Furthermore, preliminary mechanism against Colletotrichum musae of compound
23 was also investigated.
ACS Paragon Plus Environment

Page 5 of 37
Journal of Agricultural and Food Chemistry
62
63
MATERIALS AND METHODS
Chemicals. All commercially available chemicals can be used directly.
64
65
Fungal strains. Fungal strains were obtained from ACCC (Agricultural Culture Collection of China)
or College of Plant Protection, Hainan University.
66
67
68
69
70
71
72
73
Instruments. Thin layer chromatography (TLC) was used to monitor the reactions on the silica gel
GF254 (Qingdao Ocean Chemical Limited Company, China). Flash column chromatography
purification was achieved on the silica gel (300-400 mesh, Qingdao Ocean Chemical Limited
Company, China). The melting point was measured on the X-4 microscopic melting point
instrument (Beijing Taike Instruments Co., Ltd., China). 1H and 13C NMR spectra were measured
by using the Bruker 500 MHz or 600 MHz NMR spectrometer (Bruker Co., Switzerland) in
deuterium solvents with tetramethylsilane (TMS) as the internal standard. HRMS data was obtained
by using the MALDI-TOF / TOF mass spectrometer (Bruker Co., Switzerland).
74
75
Synthesis. The synthetic routes of the target compounds 6-38 were outlined in Scheme 1.
General procedure for synthesizing target compounds 6-7
76
77
78
79
Maltol (10 mmol) was dissolved in 10 mL H2O and excess of ammonia or methylamine (15
mmol) was added into the solution. The reaction solution was heated to reflux and kept for 10 h.
The solvent and ammonia or methylamine were removed in vacuo. The residue was purified by
falsh silica gel column chromatography (CH2Cl2/CH3OH = 50:1) to afford compounds 5-622.
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 6 of 37
80
81
82
83
84
85
86
87
3-Hydroxy-2-methylpyridin-4(1H)-one (6). Gray solid, mp 285-287 oC, yield = 85%. 1H NMR
(600 MHz, DMSO-d6) δ 8.01 (d, J = 5.5 Hz, 1H, pyridinone), 6.33 (d, J = 5.5 Hz, 1H, pyridinone),
2.23 (s, 3H, CH3). 13C NMR (150 MHz, DMSO-d6) δ 172.6, 154.6, 149.2, 143.0, 113.6, 14.0.
3-Hydroxy-1,2-dimethylpyridin-4(1H)-one (7). White solid, mp 259-260 oC, yield = 69%. 1H
NMR (600 MHz, DMSO-d6) δ 7.55 (d, J = 7.2 Hz, 1H, pyridinone), 6.08 (d, J = 7.2 Hz, 1H,
pyridinone), 3.62 (s, 3H, N-CH3), 2.26 (s, 3H, pyridinone-CH3). 13C NMR (150 MHz, DMSO-d6) δ
168.7, 145.3, 138.0, 129.4, 110.2, 40.9, 11.7.
General procedure for the synthesis of the target compounds 8-38
88
89
90
91
92
93
94
95
Pyrone analogues (2-5) (20 mmol) and an excess of the appropriate primary arylamine (30
mmol) were added to an acidic solution (pH = 5.0) containing water (18.0 mL), con. HCl (0.4 mL,
12 mol/L) and ethanol (2.0 mL). And the mixture was heated and maintained at 160 °C for 12 h in
an autoclave. After the reaction was completed, the reaction mixture was adjusted to pH7.0 using
sodium hydroxide solution (2 N) and the mixture was extracted with CH2Cl2 (50 mL) for three
times, then the organic phase was merged and dried with anhydrous MgSO4. The crude product was
obtained by removing solvent under vacuum and then purified by flash silica gel column
chromatography (CH2Cl2/CH3OH = 50:1) to afford compounds 8-3823-24
.
96
97
3-Hydroxy-2-methyl-1-phenylpyridin-4(1H)-one (8). White solid, mp 206-207 oC, yield = 83%.
1H NMR (500 MHz, Chloroform-d) δ 7.53 (m, J = 4.8, 1.8 Hz, 3H, Ph), 7.30 (d, J = 7.3 Hz, 1H,
98
pyridinone), 7.29 – 7.26 (m, 2H, Ph), 6.46 (d, J = 7.3 Hz, 1H, pyridinone), 2.10 (s, 3H, CH3). 13
C
99
NMR (125 MHz, Chloroform-d) δ 170.3, 145.8, 141.9, 137.6, 130.0, 129.7, 128.5, 126.9, 111.0,
100
13.8. ESI-HRMS: m/z [M+H]+ calcd. for [C12H12NO2]: 202.0863; found: 202.0858.
ACS Paragon Plus Environment

Page 7 of 37
Journal of Agricultural and Food Chemistry
o
101
3-Hydroxy-1-(4-hydroxyphenyl)-2-methylpyridin-4(1H)-one (9). Gray solid, mp 311-312 C,
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
yield = 69%. 1H NMR (600 MHz, DMSO-d6) δ 7.48 (d, J = 7.3 Hz, 1H, pyridinone), 7.23 – 7.20
(m, 2H, Ph), 6.89 – 6.86 (m, 2H, Ph), 6.18 (d, J = 7.3 Hz, 1H, pyridinone), 1.95 (s, 3H, CH3). 13
C
NMR (150 MHz, DMSO-d6) δ 169.4, 157.8, 145.0, 138.2, 133.1, 129.3, 128.0, 115.8, 110.6, 13.3.
ESI-HRMS: m/z [M+H]+ calcd. for [C12H12NO3]: 218.0812; found: 218.0807.
1-([1,1'-Biphenyl]-4-yl)-3-hydroxy-2-methylpyridin-4(1H)-one (10). Grayish white solid, mp
264-266 oC, yield = 65%. 1H NMR (600 MHz, DMSO-d6) δ 7.85 (d, J = 8.3 Hz, 2H, Ph), 7.75 (d, J
= 7.5 Hz, 2H, Ph), 7.60 (d, J = 7.3 Hz, 1H, pyridinone), 7.55 (d, J = 8.3 Hz, 2H, Ph), 7.51 (t, J = 7.6
Hz, 2H, Ph), 7.42 (t, J = 7.3 Hz, 1H, Ph), 6.23 (d, J = 7.3 Hz, 1H, pyridinone), 2.02 (s, 3H, CH3).
13C NMR (150 MHz, DMSO-d6) δ 169.7, 145.1, 140.9, 138.8, 137.9, 129.1, 128.6, 128.0, 127.8,
127.5, 126.9, 110.9, 13.4. ESI-HRMS: m/z [M+H]+ calcd. for [C18H16NO2]: 278.1176; found:
278.1182.
1-(4-Fluorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (11). Grayish white solid, mp 191-
192 oC, yield = 79%. 1H NMR (500 MHz, Chloroform-d) δ 7.31 – 7.28 (m, 2H, Ph), 7.27 (s, 1H,
pyridinone), 7.25 – 7.20 (m, 2H, Ph), 6.46 (d, J = 7.3 Hz, 1H, pyridinone), 2.10 (s, 3H, CH3). 13
C
NMR (125 MHz, Chloroform-d) δ 170.4, 163.7, 162.7 (d, J = 251.0 Hz), 145.8, 137.6 (d, J = 3.4
Hz), 128.8 (d, J = 8.9 Hz), 117.2, 117.0 (d, J = 23.1 Hz), 111.2, 13.7. ESI-HRMS: m/z [M+H]+
calcd. for [C12H11FNO2]: 220.0768; found: 220.0765.
1-(4-Chlorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (12). White solid, mp 210-212 oC,
yield = 74%. 1H NMR (600 MHz, DMSO-d6) δ 7.63 (d, J = 8.6 Hz, 2H, Ph), 7.55 (d, J = 7.3 Hz,
1H, pyridinone), 7.51 (d, J = 8.6 Hz, 2H, Ph), 6.21 (d, J = 7.3 Hz, 1H, pyridinone), 1.96 (s, 3H,
CH3). 13C NMR (150 MHz, DMSO-d6) δ 169.7, 145.0, 140.4, 137.9, 133.7, 129.6, 129.0, 128.5,
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 8 of 37
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
111.0, 13.3. ESI-HRMS: m/z [M+H]+ calcd. for [C12H11ClNO2]: 236.0473; found: 236.0479.
o
1-(4-Bromophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (13). White solid, mp 216-217 C,
yield = 63%. 1H NMR (600 MHz, DMSO-d6) δ 7.76 (d, J = 8.6 Hz, 2H, Ph), 7.54 (d, J = 7.3 Hz,
1H, pyridinone), 7.44 (d, J = 8.6 Hz, 2H, Ph), 6.21 (d, J = 7.3 Hz, 1H, pyridinone), 1.96 (s, 3H,
CH3). 13C NMR (150 MHz, DMSO-d6) δ 169.7, 140.8, 137.8, 132.5, 129.3, 128.4, 122.2, 118.5,
111.0, 13.3. ESI-HRMS: m/z [M+H]+ calcd. for [C12H11BrNO2]: 279.9968; found: 279.9971.
1-(3-Chlorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (14). Light brown solid, mp 173-
175 oC, yield = 61%. 1H NMR (600 MHz, Chloroform-d) δ 7.50 (dt, J = 15.4, 7.8 Hz, 2H, Ph), 7.33
(s, 1H, Ph), 7.28 (d, J = 5.0 Hz, 1H, Ph), 7.21 (d, J = 6.9 Hz, 1H, pyridinone), 6.47 (d, J = 7.0 Hz,
1H, pyridinone), 2.13 (s, 3H, CH3). 13C NMR (150 MHz, Chloroform-d) δ 170.4, 145.9, 142.7,
137.2, 135.7, 131.0, 130.0, 128.4, 127.4, 125.3, 111.4, 13.8. ESI-HRMS: m/z [M+H]+ calcd. for
[C12H11ClNO2]: 236.0473; found: 236.0471.
1-(2-Chlorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (15). Reddish brown solid, mp
180-182 oC, yield = 60%. 1H NMR (600 MHz, Chloroform-d) δ 7.66 – 7.40 (m, 4H, Ph), 7.17 (s,
1H, pyridinone), 6.48 (s, 1H, pyridinone), 2.03 (s, 3H, CH3). 13C NMR (150 MHz, Chloroform-d)
δ 170.5, 145.6, 139.0, 137.1, 132.5, 131.3, 130.9, 129.1, 128.7, 111.3, 29.7, 12.8. ESI-HRMS: m/z
[M+H]+ calcd. for [C12H11ClNO2]: 236.0473; found: 236.0475.
1-(2-Fluorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (16). Brown solid, mp 158-159 oC,
yield = 60%. 1H NMR (500 MHz, Chloroform-d) δ 7.52 (s, 1H, Ph), 7.32 (d, J = 5.5 Hz, 2H, Ph),
7.29 (d, J = 9.0 Hz, 1H, Ph), 7.24 (d, J = 7.2 Hz, 1H, pyridinone), 6.48 (d, J = 7.1 Hz, 1H, pyridinone),
2.09 (s, 3H, CH3). 13C NMR (125 MHz, Chloroform-d) δ 170.7, 156.4 (d, J = 252.9 Hz), 145.7,
137.7, 131.9 (d, J = 7.5 Hz), 129.0 (d, J = 12.9 Hz), 128.9, 128.8 (d, J = 4.3 Hz), 125.5 (d, J = 4.0
ACS Paragon Plus Environment

Page 9 of 37
Journal of Agricultural and Food Chemistry
145
Hz), 117.4 (d, J = 19.4 Hz), 111.5, 12.9. ESI-HRMS: m/z [M+H]+ calcd. for [C12H11FNO2]:
220.0768; found: 220.0773.
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
1-(2,6-Difluorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (17). Brown solid, mp 185-187
oC, yield = 53%. 1H NMR (500 MHz, Chloroform-d) δ 7.60 – 7.45 (m, 1H, pyridinone), 7.22 – 7.09
(m, 3H, Ph), 6.50 (d, J = 6.3 Hz, 1H, pyridinone), 2.10 (s, 3H, CH3). 13C NMR (125 MHz,
Chloroform-d) δ 171.0, 158.2 (d, J = 254.7 Hz), 145.7, 138.0, 131.7, 128.8, 118.7, 112.7 (d, J =
19.8 Hz), 111.9, 12.4. ESI-HRMS: m/z [M+H]+ calcd. for [C12H10F2NO2]: 238.0674; found:
238.0679.
o
3-Hydroxy-2-methyl-1-(p-tolyl)pyridin-4(1H)-one (18). Light brown solid, mp 256-257 C,
yield = 83%. 1H NMR (500 MHz, Chloroform-d) δ 7.28 (d, J = 8.0 Hz, 2H, Ph), 7.24 (d, J = 2.5 Hz,
1H, pyridinone), 7.11 (d, J = 8.2 Hz, 2H, Ph), 6.42 (d, J = 7.3 Hz, 1H, pyridinone), 2.42 (s, 3H, Ph-
CH3), 2.07 (s, 3H, pyridinone-CH3). 13C NMR (125 MHz, Chloroform-d) δ 170.2, 145.8, 139.8,
139.4, 137.6, 130.5, 128.8, 126.6, 110.9, 21.3, 13.7. ESI-HRMS: m/z [M+H]+ calcd. for
[C13H14NO2]: 216.1019; found: 216.1023.
1-(4-Ethylphenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (19). Light brown solid, mp 121-122
oC, yield = 79%. 1H NMR (500 MHz, Chloroform-d) δ 7.33 (d, J = 7.5 Hz, 2H, Ph), 7.28 (d, J = 6.8
Hz, 1H, pyridinone), 7.16 (d, J = 7.6 Hz, 2H, Ph), 6.44 (d, J = 6.6 Hz, 1H, pyridinone), 2.73 (q, J =
7.6 Hz, 2H, CH2), 2.09 (s, 3H, pyridinone-CH3), 1.29 (t, J = 7.6 Hz, 3H, CH3). 13C NMR (125 MHz,
Chloroform-d) δ 170.2, 145.7, 139.5, 137.6, 129.3, 128.8, 126.7, 110.9, 28.6, 15.5, 13.7. ESI-HRMS:
m/z [M+H]+ calcd. for [C14H16NO2]: 230.1176; found: 230.1184.
3-Hydroxy-2-methyl-1-(4-propylphenyl)pyridin-4(1H)-one (20). Light brown solid, mp 146-
148 oC, yield = 76%. 1H NMR (500 MHz, Chloroform-d) δ 7.30 (s, 3H, Ph and pyridinone), 7.15
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 10 of 37
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
(s, 2H, Ph), 6.44 (s, 1H, pyridinone), 2.66 (t, J = 6.9 Hz, 2H, CH2), 2.09 (s, 3H, pyridinone-CH3),
1.72 – 1.64 (m, 2H, CH2), 0.97 (t, J = 6.9 Hz, 3H, CH3). 13C NMR (125 MHz, Chloroform-d) δ
170.1, 145.6, 144.5, 139.4, 137.6, 129.8, 128.7, 126.5, 110.8, 37.6, 24.4, 13.8, 13.7. ESI-HRMS:
m/z [M+H]+ calcd. for [C15H18NO2]: 244.1332; found: 244.1335.
3-Hydroxy-1-(4-isopropylphenyl)-2-methylpyridin-4(1H)-one (21). Light brown solid, mp
193-194 oC, yield = 76%. 1H NMR (500 MHz, Chloroform-d) δ 7.35 (d, J = 7.9 Hz, 2H, Ph), 7.28
(d, J = 7.1 Hz, 1H, pyridinone), 7.16 (d, J = 8.0 Hz, 2H, Ph), 6.44 (d, J = 7.0 Hz, 1H, pyridinone),
2.99 (hept, J = 6.9 Hz, 1H, CH), 2.10 (s, 3H, pyridinone-CH3), 1.29 (d, J = 6.9 Hz, 6H, Ph-
CH(CH3)2). 13C NMR (125 MHz, Chloroform-d) δ 170.2, 150.6, 145.7, 139.5, 137.6, 128.9, 127.9,
126.7, 110.9, 34.0, 24.0, 13.8. ESI-HRMS: m/z [M+Na]+ calcd. for [C15H17NO2Na]: 266.1151;
found: 266.1155.
1-(4-Butylphenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (22). Light brown solid, mp 167-169
oC, yield = 71%. 1H NMR (600 MHz, Chloroform-d) δ 7.32 (s, 3H, Ph and pyridinone), 7.16 (s, 2H,
Ph), 6.45 (s, 1H, pyridinone), 2.70 (t, J = 6.9 Hz, 2H, CH2), 2.10 (s, 3H, pyridinone-CH3), 1.65 (s,
2H, CH2), 1.43 – 1.36 (m, 2H, CH2), 0.96 (t, J = 6.9 Hz, 3H, CH3). 13C NMR (150 MHz, Chloroform-
d) δ 170.1, 145.6, 144.7, 139.4, 137.6, 129.7, 128.8, 126.5, 110.8, 35.2, 33.4, 22.3, 13.9, 13.6. ESI-
HRMS: m/z [M+H]+ calcd. for [C16H20NO2]: 258.1489; found: 258.1485.
1-(4-(Tert-butyl)phenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (23). White solid, mp 197-198
oC, yield = 74%. 1H NMR (500 MHz, Chloroform-d) δ 7.51 (d, J = 8.4 Hz, 2H, Ph), 7.29 (d, J = 7.2
Hz, 1H, pyridinone), 7.17 (d, J = 8.4 Hz, 2H, Ph), 6.44 (d, J = 7.2 Hz, 1H, pyridinone), 2.10 (s, 3H,
pyridinone-CH3), 1.37 (s, 9H, Ph-C(CH3)3). 13C NMR (125 MHz, Chloroform-d) δ 170.2, 153.0,
ACS Paragon Plus Environment

Page 11 of 37
Journal of Agricultural and Food Chemistry
188
145.7, 139.3, 137.7, 128.8, 126.9, 126.4, 110.9, 35.0, 31.4, 13.8. ESI-HRMS: m/z [M+H]+ calcd.
for [C16H20NO2]: 258.1489; found: 258.1491.
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
1-(4-(Dimethylamino)phenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (24). Dark brown solid,
o
1
mp 214-215 C, yield = 66%. H NMR (500 MHz, Chloroform-d) δ 7.28 (d, J = 7.0 Hz, 1H,
pyridinone), 7.06 (d, J = 8.1 Hz, 2H, Ph), 6.72 (d, J = 8.1 Hz, 2H, Ph), 6.42 (d, J = 6.8 Hz, 1H,
pyridinone), 3.02 (s, 6H, N-(CH3)2), 2.09 (s, 3H, pyridinone-CH3). 13C NMR (125 MHz,
Chloroform-d) δ 170.0, 150.7, 145.6, 138.2, 130.6, 129.5, 127.3, 112.2, 110.7, 40.5, 13.7. ESI-
HRMS: m/z [M+H]+ calcd. for [C14H17N2O2]: 245.1285; found: 245.1282.
2-(4-(3-Hydroxy-2-methyl-4-oxopyridin-1(4H)-yl)phenyl)-2-methylpropanenitrile
(25).
Grayish white solid, mp 229-230 oC, yield = 68%. 1H NMR (500 MHz, Chloroform-d) δ 7.63 (d, J
= 8.2 Hz, 2H, Ph), 7.30 (d, J = 8.3 Hz, 2H, Ph), 7.24 (s, 1H, pyridinone), 6.44 (d, J = 7.2 Hz, 1H,
pyridinone), 2.09 (s, 3H, pyridinone-CH3), 1.77 (s, 6H, Ph-C(CH3)2CN). 13C NMR (125 MHz,
Chloroform-d) δ 170.4, 145.9, 143.2, 141.4, 137.4, 128.3, 127.5, 126.9, 123.9, 111.2, 37.2, 29.2,
13.8. ESI-HRMS: m/z [M+H]+ calcd. for [C16H17N2O2]: 269.1285; found: 269.1284.
o
3-Hydroxy-2-methyl-1-(m-tolyl)pyridin-4(1H)-one (26). Light brown solid, mp 142-143 C,
1
yield = 61%. H NMR (500 MHz, Chloroform-d) δ 7.40 (s, 1H, pyridinone), 7.34 – 7.26 (m, 2H,
Ph), 7.08 (s, 2H, Ph), 6.46 (s, 1H, pyridinone), 2.44 (s, 3H, Ph-CH3), 2.11 (s, 3H, pyridinone-CH3).
13C NMR (125 MHz, Chloroform-d) δ 170.2, 145.7, 141.8, 140.3, 137.4, 130.3, 129.7, 128.7, 127.4,
123.8, 110.9, 21.4, 13.7. ESI-HRMS: m/z [M+Na]+ calcd. for [C13H13NO2Na]: 238.0838; found:
238.0831.
1-(3-(Tert-butyl)phenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (27). Grayish white solid, mp
185-186 oC, yield = 60%. 1H NMR (500 MHz, Chloroform-d) δ 7.52 (d, J = 8.7 Hz, 1H, Ph), 7.44
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 12 of 37
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
(t, J = 7.8 Hz, 1H, Ph), 7.31 (d, J = 7.3 Hz, 1H, pyridinone), 7.23 (t, J = 1.9 Hz, 1H, Ph), 7.06 (d, J
= 8.8 Hz, 1H, Ph), 6.46 (d, J = 7.3 Hz, 1H, pyridinone), 2.09 (s, 3H, CH3), 1.34 (s, 9H, Ph-C(CH3)3).
13C NMR (125 MHz, Chloroform-d) δ 170.2, 153.8, 145.8, 141.7, 137.6, 129.6, 128.6, 126.6, 123.9,
123.8, 110.9, 35.1, 31.3, 13.8. ESI-HRMS: m/z [M+H]+ calcd. for [C16H20NO2]: 258.1489; found:
258.1482.
3-Hydroxy-2-methyl-1-(3-(trifluoromethyl)phenyl)pyridin-4(1H)-one (28). Brown solid, mp
188-190 oC, yield = 59%. 1H NMR (500 MHz, Chloroform-d) δ 7.81 (s, 1H, Ph), 7.78 – 7.68 (m,
1H, Ph), 7.59 (s, 1H, pyridinone), 7.57 – 7.49 (m, 1H, Ph), 7.29 (d, J = 10.9 Hz, 1H, Ph), 6.49 (s,
1H, pyridinone), 2.12 (s, 3H, CH3). 13C NMR (125 MHz, Chloroform-d) δ 170.5, 146.0, 142.2,
137.3, 132.6 (q, J = 33.2 Hz), 130.8, 130.4, 128.2, 126.5 (q, J = 3.6 Hz), 124.1 (q, J = 271.2 Hz),
124.0 (q, J = 3.6 Hz), 111.6, 13.8. ESI-HRMS: m/z [M+H]+ calcd. for [C13H11F3NO2]: 270.0736;
found: 270.0737.
1-(3,5-Dimethylphenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (29). Light brown solid, mp
193-195 oC, yield = 59%. 1H NMR (600 MHz, Chloroform-d) δ 7.28 (d, J = 7.6 Hz, 1H, pyridinone),
7.13 (s, 1H, Ph), 6.87 (s, 2H, Ph), 6.44 (d, J = 7.2 Hz, 1H, pyridinone), 2.39 (s, 6H, Ph-CH3), 2.11
(s, 3H, pyridinone-CH3). 13C NMR (150 MHz, Chloroform-d) δ 170.2, 145.7, 141.7, 139.9, 137.4,
131.1, 128.8, 124.4, 110.9, 21.3, 13.7. ESI-HRMS: m/z [M+H]+ calcd. for [C14H16NO2]: 230.1176;
found: 230.1172.
1-(3,5-Dichlorophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (30). Brown solid, mp 195-196
oC, yield = 60%. 1H NMR (600 MHz, Chloroform-d) δ 7.53 (s, 1H, pyridinone), 7.23 (s, 3H, Ph),
6.45 (d, J = 5.9 Hz, 1H, pyridinone), 2.14 (s, 3H, CH3). 13C NMR (150 MHz, Chloroform-d) δ 170.6,
ACS Paragon Plus Environment

Page 13 of 37
Journal of Agricultural and Food Chemistry
231
145.9, 143.2, 137.1, 136.4, 130.2, 127.9, 125.9, 111.6, 13.8. ESI-HRMS: m/z [M+H]+ calcd. for
[C12H10Cl2NO2]: 270.0083; found: 270.0086.
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
1-(3,5-Dichloro-4-methylphenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (31). Brown solid,
mp 205-207 oC, yield = 69%. 1H NMR (600 MHz, Chloroform-d) δ 7.27 (s, 2H, Ph), 7.25 (s, 1H,
pyridinone), 6.46 (s, 1H, pyridinone), 2.55 (s, 3H, Ph-CH3), 2.14 (s, 3H, pyridinone-CH3). 13C NMR
(150 MHz, Chloroform-d) δ 170.5, 145.9, 140.0, 137.2, 136.7, 136.5, 128.1, 126.3, 111.5, 17.5, 13.7.
ESI-HRMS: m/z [M+H]+ calcd. for [C13H12Cl2NO2]: 284.0240; found: 284.0237.
1-(3-Fluoro-4-morpholinophenyl)-3-hydroxy-2-methylpyridin-4(1H)-one (32). Grayish white
solid, mp 220-221 oC, yield = 68%. 1H NMR (600 MHz, Chloroform-d) δ 7.27 (d, J = 2.0 Hz, 1H,
pyridinone), 7.02 – 6.98 (m, 3H, Ph), 6.44 (d, J = 7.3 Hz, 1H, pyridinone), 3.92 – 3.87 (m, 4H,
morpholine), 3.19 – 3.14 (m, 4H, morpholine), 2.12 (s, 3H, CH3). 13C NMR (150 MHz, Chloroform-
d) δ 170.2, 154.81 (d, J = 251.1 Hz), 145.7, 141.2 (d, J = 8.0 Hz), 137.6, 135.26 (d, J = 9.4 Hz),
128.8, 123.2 (d, J = 3.4 Hz), 119.0 (d, J = 4.1 Hz), 115.5 (d, J = 23.1 Hz), 111.1, 66.9, 50.6 (d, J =
3.7 Hz), 13.7. ESI-HRMS: m/z [M+H]+ calcd. for [C16H18FN2O3]: 305.1296; found: 305.1299.
1-(2,3-Dihydro-1H-inden-5-yl)-3-hydroxy-2-methylpyridin-4(1H)-one (33). Brown solid, mp
182-183 oC, yield = 79%. 1H NMR (600 MHz, Chloroform-d) δ 7.31 (d, J = 7.5 Hz, 1H, pyridinone),
7.27 (d, J = 6.9 Hz, 1H, Ph), 7.08 (s, 1H, Ph), 6.98 (d, J = 7.4 Hz, 1H, Ph), 6.43 (d, J = 6.7 Hz, 1H,
pyridinone), 2.97 (t, J = 7.1 Hz, 4H, Ar-CH2), 2.16 (p, J = 6.8 Hz, 2H, Ar-CH2), 2.10 (s, 3H, CH3).
13C NMR (150 MHz, Chloroform-d) δ 170.1, 146.4, 145.9, 145.6, 134.0, 137.6, 128.8, 125.3, 124.5,
122.7, 110.7, 32.9, 32.6, 25.6, 13.7. ESI-HRMS: m/z [M+H]+ calcd. for [C15H16NO2]: 242.1176;
found: 242.1180.
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 14 of 37
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
1-(9,9-Dimethyl-9H-fluoren-2-yl)-3-hydroxy-2-methylpyridin-4(1H)-one (34). Brown solid,
mp 243-244 oC, yield = 78%. 1H NMR (600 MHz, Chloroform-d) δ 7.82 (d, J = 7.6 Hz, 1H, Ph),
7.78 – 7.76 (m, 1H, Ph), 7.49 – 7.47 (m, 1H, Ph), 7.41 – 7.37 (m, 3H, Ph), 7.30 (s, 1H, Ph), 7.22 (d,
J = 7.3 Hz, 1H, pyridinone), 6.49 (d, J = 7.1 Hz, 1H, pyridinone), 2.14 (s, 3H, pyridinone-CH3),
1.52 (s, 6H, Ar-(CH3)2). 13C NMR (150 MHz, Chloroform-d) δ 170.1, 155.5, 153.8, 145.7, 140.6,
140.5, 137.7, 137.4, 128.6, 128.4, 127.4, 125.6, 122.8, 121.2, 120.9, 120.6, 110.8, 47.3, 27.0, 13.7.
ESI-HRMS: m/z [M+H]+ calcd. for [C21H20NO2]: 318.1489; found: 318.1481.
1-(4-(Tert-butyl)benzyl)-3-hydroxy-2-methylpyridin-4(1H)-one (35). Grayish white solid, mp
190-191 oC, yield = 80%. 1H NMR (600 MHz, Chloroform-d) δ 7.38 (d, J = 8.1 Hz, 2H, Ph), 7.31
(d, J = 6.4 Hz, 1H, pyridinone), 6.95 (d, J = 8.2 Hz, 2H, Ph), 6.43 (d, J = 6.5 Hz, 1H, pyridinone),
5.05 (s, 2H, CH2), 2.29 (s, 3H, pyridinone-CH3), 1.30 (s, 9H, Ph-C(CH3)3). 13C NMR (150 MHz,
Chloroform-d) δ 170.0, 151.8, 146.5, 137.8, 132.3, 128.6, 126.3, 125.9, 111.3, 57.1, 34.7, 31.4,
12.3. ESI-HRMS: m/z [M+H]+ calcd. for [C17H22NO2]: 272.1645; found: 272.1639.
1-(4-(Tert-butyl)phenyl)-3-methoxy-2-methylpyridin-4(1H)-one (36). Light yellow solid, mp
172-174 oC, yield = 93%. 1H NMR (600 MHz, Chloroform-d) δ 7.48 (d, J = 8.4 Hz, 2H, Ph), 7.23
(d, J = 7.5 Hz, 1H, pyridinone), 7.15 (d, J = 8.4 Hz, 2H, Ph), 6.41 (d, J = 7.5 Hz, 1H, pyridinone),
3.89 (s, 3H, pyridinone-OCH3), 2.05 (s, 3H, pyridinone-CH3), 1.34 (s, 9H, Ph-C(CH3)3). 13C NMR
(150 MHz, Chloroform-d) δ 173.8, 152.9, 147.5, 140.8, 139.3, 138.8, 126.9, 126.4, 117.0, 59.5, 35.0,
31.3, 14.2. ESI-HRMS: m/z [M+Na]+ calcd. for [C17H21NO2Na]: 294.1465; found: 294.1461.
1-(4-(Tert-butyl)phenyl)-2-ethyl-3-hydroxypyridin-4(1H)-one (37). White solid, mp 198-200
oC, yield = 70%. 1H NMR (600 MHz, Chloroform-d) δ 7.50 (d, J = 8.4 Hz, 2H, Ph), 7.23 (d, J = 7.3
Hz, 1H, pyridinone), 7.20 (d, J = 8.4 Hz, 2H, Ph), 6.42 (d, J = 7.3 Hz, 1H, pyridinone), 2.53 (q, J =
ACS Paragon Plus Environment

Page 15 of 37
Journal of Agricultural and Food Chemistry
274
7.5 Hz, 2H, CH2), 1.37 (s, 9H, Ph-C(CH3)3), 1.01 (t, J = 7.5 Hz, 3H, CH3). 13C NMR (150 MHz,
Chloroform-d) δ 170.4, 153.1, 145.4, 139.1, 137.8, 134.5, 126.7, 126.6, 110.9, 35.0, 31.4, 20.5,
12.6. ESI-HRMS: m/z [M+H]+ calcd. for [C17H22NO2]: 272.1645; found: 272.1649.
275
276
277
278
279
280
281
282
283
284
285
1-(4-(Tert-butyl)phenyl)-2,6-dimethylpyridin-4(1H)-one (38). Light yellow solid, mp 209-210
oC, yield = 86%. 1H NMR (600 MHz, Chloroform-d) δ 7.52 (d, J = 8.3 Hz, 2H, Ph), 7.10 (d, J = 8.3
Hz, 2H, Ph), 6.34 (s, 2H, pyridinone), 1.91 (s, 6H, pyridinone-CH3), 1.36 (s, 9H, Ph-C(CH3)3). 13
C
NMR (150 MHz, Chloroform-d) δ 179.2, 153.2, 149.6, 136.8, 127.3, 127.2, 117.2, 35.0, 31.4, 21.7.
ESI-HRMS: m/z [M+H]+ calcd. for [C17H22NO]: 256.1696; found: 256.1698.
In vitro antifungal and antibacterial bioassay. The antifungal activity was evaluated by the
mycelial growth inhibitory rate method according to previously reported procedures25-26, and the
antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo) was determined using the
turbidimeter test27.
286
287
288
289
In vivo antifungal bioassay.
Potted plant experiment
Evaluation of antifungal activity of compound 23 on potted plants by literature method28.
In vivo protective activity against postharvest diseases of mango
290
291
292
293
294
Compound 23 was dissolved in DMF and diluted to 200 µg mL-1 with water containing 0.5%
(v/v) Tween 80. The mango fruits were immersed in the solution for 5 minutes, and dried naturally,
15 fruits per treatment, repeated 3 times29. Stilled water containing DMF and Tween 80 was used
as a control, and azoxystrobin (200 μg mL-1) was used as a positive control. The treated fruit were
stored in a moisture chamber at 28 °C and 80% RH. The disease was observed and graded every
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 16 of 37
295
296
297
298
299
300
301
302
two days.
The classification grades are as follows:
Grade 0: no lesion.
Grade 1: lesion area ≤ 5%.
Grade 3: 5% ＜ lesion area ≤ 10%.
Grade 5: 10% ＜ lesion area ≤ 25%.
Grade 7: 25% ＜ lesion area ≤ 50%.
Grade 9: lesion area ＞ 50%.
∑
(incidence number of all grades × grade value of this level)
Disease index =
Control effect =
× 100
303
304
total number of mango fruit × highest grade value
control disease index ― treatment disease index
× 100%
control disease index
305
306
307
In vivo antibacterial bioassay. The curative and protection activities of compounds 22 and 23
against Xoo were measured by Schaad’s method30-31. Zhongshengmycin (Yuanye, Shanghai, China)
served as the positive control.
308
309
310
311
Hyphal morphology observation of C. musae. Compound 23 was added in sterilized Czapek
media which had incubated C. musae for 4 days, and the final concentration was 15 μg mL-1. Then
0
incubated together at 27 C. After 24h, observed under microscope (OLYMPUS BX53). Acetone
(1.0 mL) served as the control32.
312
Detection of cellular oxygen content. The mycelium of C. musae which had been cultured for 4
ACS Paragon Plus Environment

Page 17 of 37
Journal of Agricultural and Food Chemistry
313
days was filtered and washed three times with double distilled water. Hyphae (1 g) treated with
compound 23 at 7.5, 15, and 30μg mL-1 were placed in 20 mL centrifuge tube, azoxystrobin was
used as the positive control, and then measured the cellular oxygen at 0, 1, 3 and 6 h gradually by
optical oxygen dissolution meter (STRARTER 400D)33.
314
315
316
317
318
319
The experimental methods for transmission electron microscopy, detecting cell membrane
permeability, soluble protein content and reducing sugar content refer to the literature method
previously published by our research group34.
320
321
All the detail experimental methods were given in the Supporting Information.
RESULTS AND DISCUSSION
322
323
324
325
326
327
Synthesis. The chemical structure and synthetic method are shown in Scheme 1. All compounds
are obtained by one-step reaction of pyrone and the corresponding amine, and compounds 6-7 can
be obtained with a normal pressure reaction, while the reaction for producing compounds 8-38 can
be carried out only in an autoclave to obtain a higher yield, 33 target compounds were obtained with
yields of 53-93%, and all of the target compounds were characterized by HRMS, 1H NMR and 13
NMR data.
C
328
329
330
331
332
In vitro antifungal activities of compounds 6-38 and structure-activity relationships analysis.
The fungicidal activities of 33 target compounds are shown in Table 1 and Table 2. Table 1 showed
the preliminary screening of antifungal activities of the target compounds 6-38 at 50 μg mL-1, and
the EC50 values of selected compounds with excellent fungicidal activities were determined (Table
2).
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 18 of 37
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
The structure-activity relationship (SAR) shown in Table 1 and Table 2 was obvious. Firstly,
the antifungal acitivities of compounds 1 (maltol), 6, 7 and 8 showed that N-phenyl group on the
pyridinone ring was beneficial to antifungal activity. In addition, the substituents on the benzene
ring were crucial to antifungal activity and ortho-substituents were unfavorable for the antifungal
activity, for example, compound 12 (4-Cl) and compound 18 (4-CH3) exhibited more broad-
spectrum antifungal activities than compound 9 (4-OH), 11 (4-F), 13 (4-Br), 15 (2-Cl), 16 (2-F) and
17 (2,6-di-F). However, meta-substituents displayed different SAR, for example, the antifungal
activities of compound 14 (3-Cl) were much better than that of compound 12 (4-Cl), whereas
compound 26 (3-CH3) showed comparable antifungal activities with compound 18 (4-CH3).
Secondly, it was showed that the antifungal activities of target compounds increased gradually with
increase in carbon chain or steric hindrance by comparing the fungicidal activities of compounds 18
(4-methyl), 19 (4-ethyl), 20 (4-n-propyl), 21 (4-iso-propyl), 22 (4-n-butyl) and 23 (4-tert-butyl).
Especially, compound 23 achieved more than 94% inhibition against 9 species of plant pathogenic
fungi at 50 μg mL-1 and the EC50 values ranged from 1.911 to 18.192 μg mL-1 (Table 2), and
compound 23 presented much better fungicidal activities than azoxystrobin (Table 1 and Table 2,
EC50 values distributed between 5.268 and 147.136 μg mL-1). When the carbon atom of alkyl group
on phenyl ring replaced with nitrogen atom, the fungicidal activities of target compounds such as
compound 24 (4-dimethylamino) and 32 (4-morpholinyl) decreased significantly in comparison
with compound 21 (4-iso-propyl), and C-N bond decomposition in the fungi may be responsible for
the lower fungicidal activity. Furthermore, it was found that the replacement of tert-butyl group
(compound 23) with an electron-withdrawing group (2-cyanopropan-2-yl group, compound 25) on
the phenyl ring led to a sharp decrease in the antifungal activity, and the introduction of
ACS Paragon Plus Environment

Page 19 of 37
Journal of Agricultural and Food Chemistry
355
trifluoromethyl group on the phenyl ring (compound 28) could enhance the fungicidal activity by
comparing with compound 26 (3-CH3). Thirdly, meta-position di-substituted groups on the phenyl
ring enhanced the fungicidal activity significantly, for instance, the fungicidal activities of
compounds 29 (3,5-di-CH3) and 30 (3,5-di-Cl) were superior to compound 26 (3-CH3) and 14 (3-
Cl). Moreover, compound 31 (3,5-di-Cl-4-CH3) showed excellent and broad-spectrum antifungal
activity, which proved that the combination of chlorine atom and alkyl group contributed to the
improvement of antifungal activity. Both the para and meta-alkyl substitutions were favorable for
antifungal activity, so the indane (compound 33) and 9,9-dimethylfluorene (compound 34) groups
were introduced to the molecules and both compounds presented good antifungal activity (Table 1
and Table 2). The antifungal acitivities of compounds 23 and 35 showed that the insertion of a
methylene group between the benzene ring and the pyridinone ring reduced the antifungal activity,
and which proved that phenyl ring and the pyridinone ring conjugation was important to the
antifungal activity. Finally, the hydroxyl and methyl substituents on the pyridinone ring were critical
to fungicidal activity, for instance, the fungicidal activities of compounds 36, 37 and 38 decreased
sharply in comparison with compound 23 (Table 1).
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
In vitro antibacterial activity. Since compounds 22 and 23 have excellent antifungal activity, their
antibacterial activity continued to be studied. Compounds 22 and 23 exhibited excellent in vitro
antibacterial activity (84.54% and 83.93% respectively) against Xoo at concentration of 100 μg mL-1,
which was comparable to zhongshengmycin (86.09%). The corresponding EC50 values of
compounds 22 and 23 were 29.567 μg mL-1 and 26.398 μg mL-1 (Table 3).
375
In vivo antifungal activities of compound 23.
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 20 of 37
376
Potted plant experiment
377
378
379
380
381
382
In order to further investigate the potential antifungal activities in vivo of compound 23, the in
vivo protective activity on potted plant were carried out. The bioassay results showed that compound
23 could control plant fungal diseases (Corynespora cassiicola, Pseudoperonospora cubensis,
Fusarium graminearum, Rhizoctonia solani and Botrytis cinerea) effectively (Table 4). Compound
23 has an above 95% control effect against other plant pathogenic fungi except Rhizoctonia solani
(control effect was 75%).
383
Control effect of compound 23 against postharvest diseases of mango
384
385
386
387
388
389
390
In view of compound 23 presented excellent in vivo protective activity against Botryodiplodia
theobromae and Colletotrichum musae, the efficacy of compound 23 to control postharvest diseases
of mango fruits were investigated. As shown in Table 5, on day 14, the control effect of compound
23 (200 μg mL-1) on postharvest diseases of mango was 87.91%, while azoxystrobin was only
28.57%. The mango treated with compound 23 showed no odor, and the taste was not different from
the control. Therefore, compound 23 had no effect on the quality of mango and prolonged the
storage time of mango fruits.
391
392
393
394
In vivo antibacterial activity. The data showed in Table 6 indicated that compounds 22 and 23
exerted a better in vivo curative activity (49.30% and 52.42%) and protective activity (50.37% and
52.70%) in controlling rice bacterial leaf blight at 200 μg mL-1 than zhongshengmycin (42.90%,
200 μg mL-1).
395
Preliminary action mode of compound 23 against C. musae
ACS Paragon Plus Environment

Page 21 of 37
Journal of Agricultural and Food Chemistry
396
Hyphae morphology observation
397
398
399
400
From Figure 2, we can see that the hyphal in the control treatment was usually slippy and had
normal branches. The color and the endosome of hypha were evenly distributed. However, after 24
h treatment with compound 23 at 15 μg mL-1, almost all hyphal of C. musae became coarser,
distorted and deformed.
401
Transmission electron microscope analysis
402
403
404
405
406
From Figure 3, we can find that the cell structure in control treatment is clear with complete
cell wall (CW) and plasma membrane (PM), uniform cytoplasm, mitochondria and other organelles
(panels a and c). Meanwhile, some cell structures treated with compound 23 were damaged, for
example folds in cell membranes, blurred and even disappeared mitochondria, the disintegrated
organelles in the cell and a large number of vesicles in the cytoplasm (panels d and f).
407
Cell membrane permeability
408
409
410
411
412
413
With the extension of treatment time, the relative seepage ratio of the cell membrane treated
with compound 23 (7.5, 15, 30 μg mL-1) were much higher than the control treatment. For example,
treatments with compound 23 (7.5, 15, 30μg mL-1) for 6 h, the relative permeability rates were
27.64%, 39.60% and 50.42% respectively, while control treatment was 17.38%. The results showed
that the cell membrane treated with compound 23 was destroyed quickly. This proved that the cell
membrane of C. musae was damaged by compound 23 (Figure 4A).
414
415
Cellular oxygen content
When C. musae was treated with compound 23 (7.5, 15, 30 μg mL-1) and azoxystrobin (15 μg
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 22 of 37
416
417
418
419
420
421
422
423
mL-1), the cellular oxygen content was shown in Figure 4B. Different concentrations of compound
23 have different inhibition rates on the mycelium oxygen consumption of C. musae After 5 h
treatment, the inhibition rates of compound 23 (7.5, 15, 30 μg mL-1) were 10.46%, 15.27% and
18.03%, the inhibition rates of azoxystrobin was 16.75%. Therefore there were no significant
difference between compound 23 (15 μg mL-1) and azoxystrobin (15 μg mL-1). The results proved
that compound 23 may interfere with the respiration of C. musae like azoxystrobin. What interesting
is that there are two natural products containing pyridone substructures named ilicicolin H and
funicolosin, which are proven inhibitors of complex III in the respiration chain35-36
.
424
Soluble protein content
425
426
427
428
From Figure 4C, the soluble protein content in mycelium of C. musae which was treated with
compound 23 (7.5, 15 and 30 μg mL-1) was higher than the control. After 24 h treatment, the soluble
protein content of treated were 1.145, 1.132 and 1.128 mg/mL, which were about 30% higher than
the control.Mycelial reducing sugar content
429
430
431
432
Throughout the experiment, the mycelial reducing sugar content in mycelium of C. musae
which was treated with compound 23 was lower than the control (Figure 4D). When the mycelium
of C. musae was treated with compound 23 (7.5, 15 and 30 μg mL-1) for 24 h, the contents were
15.57%, 7.55%, and 9.91% lower than the control.
433
434
435
436
In summary, a series of N-aryl-pyridine-4-ones were designed and synthesized, and then their
fungicidal, bactericidal activities and preliminary action mechanism against C. musae were
investigated. The results showed that compound 23 displayed significant fungicidal activity in vitro
and in vivo. In addition, this study also found that compounds 22 and 23 can effectively control rice
ACS Paragon Plus Environment

Page 23 of 37
Journal of Agricultural and Food Chemistry
437
bacterial leaf blight. The preliminary action mechanism investigation indicated that compound 23
exerted its fungicidal activity through two ways. On the one hand, compound 23 may attack on the
mycelium cell membranes of C. musae and affected their relative permeability. On the other hand,
compound 23 may attack on the mitochondria of C. musae and affected its respiratory pathways. In
addition, hyphal respiratory oxygen consumption was not significantly associated with mycelial
growth. The dependence of hyphae on vegetative growth and respiration is weak. Therefore, the
author speculates that in addition to the energy metabolism of fungi, compound 23 may also affect
other aspects (such as soluble protein content and reducing sugar content) of fungal metabolism,
and further research is needed on this aspect. These findings indicated that this series of N-aryl-
pyridine-4-ones can be used to develop as potential agrochemical fungicides and bactericides. In
addition, toxicity studies and action site of compound 23 need to go further approach.
438
439
440
441
442
443
444
445
446
447
448
ACKNOWLEGEMENT
449
450
451
This work was financially supported by the National Science Foundation of China (No. 21462028),
the Startup Foundation for Introduced Talents of Hainan University (kyqd1640) and Annual Science
and Technology Project of Hainan Provincial Tobacco Company of CNTC (No. 2018003).
452
453
SUPPORTING INFORMATION
The Supporting Information is available free of charge at https://pubs.acs.org/doi/ XXXX.
1
454
455
456
HRMS, H NMR and 13C NMR spectra for the target compounds 6-38, EC50 values of target
compounds 21-23, 27 and 30-35 against phytopathogens, detailed bio-assay methods and in vivo
fungicidal effect pictures of compound 23.
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 24 of 37
457
REFERENCES
458
459
460
1. Dean, R.; Van, K. J. A. L.; Pretorius, Z. A.; Hammond-Kosack, K. E.; Di, P. A.; Spanu, P. D.;
Rudd, J. J.; Dickman, M.; Kahmann, R.; Ellis, J.; Foster, G. D., The Top 10 fungal pathogens in
molecular plant pathology. Mol Plant Pathol 2012, 13 (4), 414-30.
461
462
463
2. Li, P.; Tian, P.; Chen, Y.; Song, X.; Xue, W.; Jin, L.; Hu, D.; Yang, S.; Song, B., Novel
bisthioether derivatives containing a 1,3,4-oxadiazole moiety: design, synthesis, antibacterial and
nematocidal activities. Pest Manage. Sci. 2018, 74 (4), 844-852.
464
465
3. Wang, C.; Yang, Z.; Tang, L.; Wang, X.; Zhang, Q., Potential Risk and Mechanism of
Microcystin Induction by Chiral Metalaxyl. Environ. Sci. Technol. Lett. 2018, 5 (11), 635-640.
466
467
468
4. Kaonga, C. C.; Chidya, R. C. G.; Kosamu, I. B. M.; Abdel-dayem, S. M.; Mapoma, H. W. T.;
Thole, B.; Mbewe, R.; Sakugawa, H., Trends in usage of selected fungicides in Japan between 1962
and 2014: a review. Int. J. Environ. Sci. Technol. 2018, 15 (8), 1801-1814.
469
470
5. Chen, D.-p.; Wang, L.-x.; Gao, T.-y., Absorption spectroscopy detection of fungicide residues
of propineb in vegetables. Anhui Nongye Kexue 2015, 43 (12), 130-131, 138.
471
472
473
6. Ata, R.; Yildiz Tore, G., Characterization and removal of antibiotic residues by NFC-doped
photocatalytic oxidation from domestic and industrial secondary treated wastewaters in Meric-
Ergene Basin and reuse assessment for irrigation. J. Environ. Manage. 2019, 233, 673-680.
474
475
7. Saad, M. M., The risk of human exposure to antibiotic residues from food of both animal and
plant origin. Eur. J. Biomed. Pharm. Sci. 2016, 3 (5), 12-15.
476
477
478
8. Ye, T.; Ma, Z.; Bi, Q.; Niu, F.; Han, X.; Zhang, X.; Wang, W.; Zhang, L., Research advances
on the resistance of plant pathogenic fungi to SBIs fungicides. Nongyaoxue Xuebao 2012, 14 (1),
1-16.
479
480
9. Sundin, G. W.; Wang, N., Antibiotic Resistance in Plant-Pathogenic Bacteria. Annu. Rev.
Phytopathol. 2018, 56, 161-180.
481
482
10. Jiang, J.; Ding, L.; Michailides, T. J.; Li, H.; Ma, Z., Molecular characterization of field
azoxystrobin-resistant isolates of Botrytis cinerea. Pestic. Biochem. Physiol. 2009, 93 (2), 72-76.
483
484
485
11. Ma, D.; Jiang, J.; He, L.; Cui, K.; Mu, W.; Liu, F., Detection and characterization of Qoi-
resistant Phytophthora capsici causing pepper phytophthora blight in China. Plant Dis. 2018, 102
(9), 1725-1732.
486
487
12. Hagerty, C. H.; Anderson, N. P.; Mundt, C. C., Temporal dynamics and spatial variation of
azoxystrobin and propiconazole resistance in Zymoseptoria tritici: a hierarchical survey of
ACS Paragon Plus Environment

Page 25 of 37
Journal of Agricultural and Food Chemistry
488
commercial winter wheat fields in the Willamette Valley, Oregon. Phytopathology 2017, 107 (3),
489
345-352.
490
491
492
13. Watanabe, H.; Horinouchi, H.; Muramoto, Y.; Ishii, H., Occurrence of azoxystrobin-resistant
isolates in Passalora fulva, the pathogen of tomato leaf mould disease. Plant Pathol. 2017, 66 (9),
1472-1479.
493
494
495
14. Furuya, S.; Suzuki, S.; Kobayashi, H.; Saito, S.; Takayanagi, T., Rapid method for detecting
resistance to a QoI fungicide in Plasmopara viticola populations. Pest Manage. Sci. 2009, 65 (8),
840-843.
496
497
498
15. Forster, H.; McGhee, G. C.; Sundin, G. W.; Adaskaveg, J. E., Characterization of streptomycin
resistance in isolates of Erwinia amylovora in California. Phytopathology 2015, 105 (10), 1302-
1310.
499
500
501
16. Han, H. S.; Koh, Y. J.; Hur, J.-S.; Jung, J. S., Occurrence of the strA-strB streptomycin
resistance genes in Pseudomonas species isolated from kiwifruit plants. J. Microbiol. (Seoul, Repub.
Korea) 2004, 42 (4), 365-368.
502
503
17. Moller, W. J.; Schroth, M. N.; Thomson, S. V., The scenario of fire blight and streptomycin
resistance. Plant Dis. 1981, 65 (7), 563-8.
504
505
18. Sun, R.; Liang, C.; Zhu, X.; Ding, X.; Chen, B.; Song, W. Broad-spectrum botanical fungicide
and its preparation and application. CN108902153A, 2018.
506
507
508
19. Guo, N.; Li, C.; Liu, Q.; Liu, S.; Huan, Y.; Wang, X.; Bai, G.; Yang, M.; Sun, S.; Xu, C.; Shen,
Z., Maltol, a food flavor enhancer, attenuates diabetic peripheral neuropathy in streptozotocin-
induced diabetic rats. Food Funct. 2018, 9 (12), 6287-6297.
509
510
511
20. Cunningham, J. E.; Pickard, M. A., Maltol, a metabolite of Scytalidium uredinicola which
inhibits spore germination of Endocronartium harknessii, the western gall rust. Can. J. Microbiol.
1985, 31 (11), 1051-5.
512
513
21. Erol, D. D.; Yulug, N., Synthesis and antimicrobial investigation of thiazolinoalkyl-4(1H)-
pyridones. Eur. J. Med. Chem. 1994, 29 (11), 893-7.
514
515
516
22. Sabet, R.; Fassihi, A., QSAR study of antimicrobial 3-hydroxypyridine-4-one and 3-
hydroxypyran-4-one derivatives using different chemometric tools. Int. J. Mol. Sci. 2008, 9 (12),
2407-2423.
517
518
23. Scott, L. E.; Telpoukhovskaia, M.; Rodriguez-Rodriguez, C.; Merkel, M.; Bowen, M. L.; Page,
B. D. G.; Green, D. E.; Storr, T.; Thomas, F.; Allen, D. D.; Lockman, P. R.; Patrick, B. O.; Adam,
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 26 of 37
519
520
M. J.; Orvig, C., N-Aryl-substituted 3-(β-D-glucopyranosyloxy)-2-methyl-4(1H)-pyridinones as
agents for Alzheimer's therapy. Chem. Sci. 2011, 2 (4), 642-648.
521
522
523
24. Agrawal, A.; Johnson, S. L.; Jacobsen, J. A.; Miller, M. T.; Chen, L.-H.; Pellecchia, M.; Cohen,
S. M., Chelator Fragment Libraries for Targeting Metalloproteinases. ChemMedChem 2010, 5 (2),
195-199.
524
525
526
25. Grasso, V.; Palermo, S.; Sierotzki, H.; Garibaldi, A.; Gisi, U., Cytochrome b gene structure
and consequences for resistance to Qo inhibitor fungicides in plant pathogens. Pest Manage. Sci.
2006, 62 (6), 465-472.
527
528
529
26. Romanazzi, G.; Mancini, V.; Feliziani, E.; Servili, A.; Endeshaw, S.; Neri, D., Impact of
alternative fungicides on grape downy mildew control and vine growth and development. Plant Dis.
2016, 100 (4), 739-748.
530
531
27. Kitagawa, H.; Kumura, K.; Takahata, S.; Iida, M.; Atsumi, K., 4-Pyridone derivatives as new
inhibitors of bacterial enoyl-ACP reductase FabI. Bioorg. Med. Chem. 2007, 15 (2), 1106-1116.
532
533
534
28. Guan, A.; Wang, M.; Yang, J.; Wang, L.; Xie, Y.; Lan, J.; Liu, C., Discovery of a New
Fungicide Candidate through Lead Optimization of Pyrimidinamine Derivatives and Its Activity
against Cucumber Downy Mildew. J. Agric. Food Chem. 2017, 65 (49), 10829-10835.
535
536
537
538
29. Feng, G.; Zhang, X.-S.; Zhang, Z.-K.; Ye, H.-C.; Liu, Y.-Q.; Yang, G.-Z.; Chen, C.; Chen, M.;
Yan, C.; Wang, L.-Y.; Zhang, J.-X.; Zhang, J., Fungicidal activities of camptothecin semisynthetic
derivatives against Colletotrichum gloeosporioides in vitro and in mango fruit. Postharvest Biol.
Technol. 2019, 147, 139-147.
539
540
541
30. Li, P.; Hu, D.; Xie, D.; Chen, J.; Jin, L.; Song, B., Design, Synthesis, and Evaluation of New
Sulfone Derivatives Containing a 1,3,4-Oxadiazole Moiety as Active Antibacterial Agents. J. Agric.
Food Chem. 2018, 66 (12), 3093-3100.
542
543
544
31. Schaad, N. W.; Wang, Z. K.; Di, M.; McBeath, J.; Peterson, G.; Bonde, M. R., An improved
infiltration technique to test the pathogenicity of Xanthomonas oryzae pv. oryzae in rice seedlings.
Seed Science and Technology 1996, 24, 449-456.
545
546
547
548
32. Liu, F.; Luo, X.-Q.; Song, B.-A.; Bhadury, P. S.; Yang, S.; Jin, L.-H.; Xue, W.; Hu, D.-Y.,
Synthesis and antifungal activity of novel sulfoxide derivatives containing trimethoxyphenyl
substituted 1,3,4-thiadiazole and 1,3,4-oxadiazole moiety. Bioorg. Med. Chem. 2008, 16 (7), 3632-
3640.
549
550
33. Jin, L.-h.; Chen, C.-j.; Wang, J.-x.; Chen, Y.; Zhou, M.-g., Activity of azoxystrobin and SHAM
of four plant pathogens. Zhongguo Nongye Kexue (Beijing, China) 2007, 40 (10), 2206-2213.
ACS Paragon Plus Environment

Page 27 of 37
Journal of Agricultural and Food Chemistry
551
34. Song, X.; Zhu, X.; Li, T.; Liang, C.; Zhang, M.; Shao, Y.; Tao, J.; Sun, R., Dehydrozingerone
Inspired Discovery of Potential Broad-Spectrum Fungicidal Agents as Ergosterol Biosynthesis
Inhibitors. J. Agric. Food Chem. 2019, 67 (41), 11354-11363.
552
553
554
555
35. Tsai, A.-L.; Olson, J.; Palmer, G., The kinetics of reoxidation of yeast complex III. The Journal
of biological chemistry 1987, 262, 8677-84.
556
557
558
36. Rotsaert, F. A. J.; Ding, M. G.; Trumpower, B. L., Differential efficacy of inhibition of
mitochondrial and bacterial cytochrome bc1 complexes by center N inhibitors antimycin, ilicicolin
H and funiculosin. Biochim. Biophys. Acta, Bioenerg. 2008, 1777 (2), 211-219.
559
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 28 of 37
560
Table 1. In vitro fungicidal activity data of target compounds at 50 μg mL-1
inhibition rate (%)
Compound
B.Ta
F.G
N.D
P.O
F.O
C.M
P.C
B.C
S.S
6
7
35.5±0.2 24.0±0.1 26.3±0.2 29.0±0.3 12.1±0.7 11.0±0.4 32.3±0.5 25.5±0.1 15.4±0.2
37.1±0.7 36.1±0.4 39.4±0.1 32.5±0.2 14.9±0.5 24.9±0.5 33.7±0.8 39.6±0.3 25.7±0.6
40.0±0.6 45.3±0.2 40.4±0.3 69.7±0.2 39.7±0.0 30.2±0.4 52.0±0.4 42.1±0.2 36.6±0.2
8
9
44.2±0.1 10.8±0.2 10.8±0.1
65.5±0.1 8.4±1.1 9.2±0.7
7.9±0.6
10.9±0.4 79.9±0.7 20.2±0.4 19.3±0.5 21.3±0.7
8.8±0.5 80.0±0.6 29.4±0.9 29.0±0.9 6.3±1.2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
2(maltol)
11.1±0.4
14.3±0.8 26.9±0.8 11.2±0.2 21.9±0.7 25.2±0.1 34.5±0.4 37.9±0.7 22.9±0.8 31.8±0.9
49.6±0.5 36.4±0.5 16.5±0.2 25.8±1.2 36.4±0.9 38.3±0.8 47.9±0.6 31.2±0.6 33.1±0.9
48.5±0.7 21.2±0.8 14.2±0.5 16.4±0.5 29.0±0.3 34.6±0.4 38.2±0.3 17.0±0.4 17.0±0.2
60.3±0.6 100±0.0 73.0±0.7 41.0±0.4 100±0.0 54.5±0.4 72.5±0.4 54.9±0.7 24.6±0.4
30.2±0.8 51.5±0.8 21.8±0.8 32.8±0.7 35.5±0.2 48.6±0.2 43.7±0.4 48.2±0.4 23.5±0.7
25.9±0.2 17.5±0.2
4.9±0.4
15.2±0.5 22.4±0.5 45.9±0.4 37.6±0.6 14.3±0.7 19.0±0.8
33.1±0.3 21.6±0.2 10.2±0.1 18.7±0.7 25.3±0.5 68.9±0.5 45.8±0.8 18.1±0.8 21.4±0.2
68.1±0.6 25.5±0.7 30.8±0.3 28.4±0.4 42.5±0.7 49.2±0.0 48.3±0.2 27.4±0.2 38.2±0.2
89.6±0.7 31.2±0.7 63.1±0.2 67.3±0.1 100±0.0 75.0±0.6 53.7±0.9 23.6±0.6 71.7±0.6
100±0.0 47.2±0.3 74.2±0.6 80.9±0.6 100±0.0 79.8±0.4 60.3±0.7 27.5±0.4 78.6±0.1
100±0.0 78.0±0.2 91.4±0.8 88.6±0.8 100±0.0 82.8±0.5 100±0.0 70.9±0.3 73.8±0.2
100±0.0 70.9±0.7 82.5±0.7 100±0.0
100±0.0 100±0.0 94.0±0.3 100±0.0
30.9±0.7 14.2±0.8 13.3±0.9 28.0±0.9 63.4±0.8 20.2±0.8 42.8±0.8 21.9±0.7
40.6±0.1 23.5±0.3 1.6±0.3 9.1±0.4 15.9±0.5 10.0±0.4 44.6±0.5 6.3±0.3
100±0.0
100±0.0 84.8±0.3 75.2±0.8 100±0.0
100±0.0 99.0±0.3 100±0.0 95.0±0.4 100±0.0
9.5±0.2
6.5±0.8
45.5±0.5 29.6±0.2 38.1±0.8 13.8±0.3 67.2±0.7 44.9±0.5 61.3±0.5 21.0±0.5 35.4±0.4
86.5±0.4 78.5±0.7 100±0.0 69.2±0.3 100±0.0 100±0.0 78.5±0.6 85.9±0.2 83.6±0.6
47.7±0.4 80.3±0.8 40.4±0.4 15.9±0.1 74.1±0.7 86.5±0.8 74.8±0.7 49.7±0.5 47.6±0.4
66.1±0.1 73.7±0.1 77.9±0.7 70.1±0.1 100±0.0 84.0±0.5 68.8±0.5 58.6±0.6 79.9±0.8
64.3±0.4 100±0.0 76.1±0.8 53.6±0.5 100±0.0 55.5±0.4 100±0.0 71.9±0.7 70.0±0.7
82.5±0.8 100±0.0
20.7±0.4 23.7±0.4 48.8±0.7 11.0±0.1 10.5±0.1
100±0.0
84.1±0.8 100±0.0 86.1±0.8 40.1±0.4 49.3±0.1 75.4±0.5 49.5±0.3 80.5±0.4 100±0.0
82.5±0.8 100±0.0 87.0±0.2 100±0.0 100±0.0 100±0.0 60.0±0.6 72.8±0.8 68.9±0.2
100±0.0
100±0.0
100±0.0
100±0.0
100±0.0 79.3±0.7 76.8±0.8
9.6±0.1
35.7±0.7 9.8±0.5 14.1±0.5
100±0.0 79.8±0.6 63.3±0.6 100±0.0 66.4±0.6 100±0.0 78.4±0.4 76.2±0.4
67.0±0.6 21.7±0.2 46.8±0.6 18.5±0.1 17.9±0.1 100±0.0 55.4±0.5 32.0±0.6 37.4±0.3
69.4±0.6 23.8±0.2 75.1±0.6 65.1±0.6 60.4±0.6 65.6±0.4 49.7±0.4 44.5±0.5 60.3±0.5
30.6±0.7 29.1±0.7
6.2±0.0
12.2±0.4 55.8±0.5 68.5±0.5 47.9±0.4 40.6±0.4 33.3±0.2
7.0±0.6 39.0±0.2 13.3±0.1 23.7±0.2 17.2±0.1 14.6±0.8
30.4±0.7 14.1±0.9 16.6±0.9
Azoxystrobin 43.6±0.4 68.0±0.2 68.3±0.2 59.0±0.5 70.0±0.8 51.1±0.8 69.0±0.3 33.0±0.3 95.0±0.5
a
561
562
563
B.T: Botryodiplodia theobromae; F.G: Fusarium graminearum; N.D: Neoscytalidium dimidiatum; P.O:
Pyricularia oryae; F.O: Fusarium oxysporum; C.M: Colletotrichum musae; P.C: Phytophthora capsici; B.C:
Botrytis cinerea; S.S: Sclerotinia sclerotiorum.
ACS Paragon Plus Environment

Page 29 of 37
Journal of Agricultural and Food Chemistry
564
Table 2. EC50 value of target compounds against plant pathogenic fungi
EC50 (μg mL-1)
Compound
B.Ta
F.G
N.D
P.O
F.O
C.M
P.C
B.C
S.S
21
22
23
27
30
31
33
34
35
2.749
3.601
25.433
26.183
18.192
21.644
17.046
8.942
11.473
5.479
14.113
12.214
9.984
18.160
12.542
14.554
8.604
13.038
14.487
12.840
13.846
43.338
9.533
16.588
21.617
10.781
18.637
24.242
21.427
32.147
50.537
46.558
24.871
19.617
12.783
8.534
8.051
11.058
6.977
1.911
3.928
12.549
44.376
6.858
8.154
14.596
43.893
17.694
20.207
62.095
15.351
17.897
17.299
14.995
15.078
21.135
16.293
20.825
35.106
6.601
16.583
4.210
15.571
10.888
20.465
40.454
18.454
19.200
6.581
23.738
18.215
31.755
5.268
13.187
10.065
19.755
18.946
10.824
51.987
10.054
11.830
14.882
1.181
22.238
22.040
52.509
Azoxystrobin 147.136
18.807 102.728 11.497
a
565
B.T: Botryodiplodia theobromae; F.G: Fusarium graminearum; N.D: Neoscytalidium dimidiatum; P.O:
Pyricularia oryae; F.O: Fusarium oxysporum; C.M: Colletotrichum musae; P.C: Phytophthora capsici; B.C:
Botrytis cinerea; S.S: Sclerotinia sclerotiorum.
566
567
568
569
570
Table 3. In vitro antibacterial activity of compounds against Xanthomonas oryzae pv. oryzae
inhibition rate (%)
(100 μg mL-1)
84.54±0.41
EC50
(μg mL-1)
29.567
26.398
14.496
treatment
toxic regression eq
R2
Compound 22
Compound 23
y=-5.25+3.54x
y=-4.90+3.42x
y=-3.03+2.56x
0.992
0.976
0.957
83.93±0.27
Zhongshengmycin
86.09±0.52
571
572
573
Table 4. Potted plant experiment of compound 23 (% Control) (400 μg mL-1)
Compound
C.Ca
P.C
F.G
R.S
B.C
23
98±1
100±0
98±1
75±3
95±3
574
575
C.C: Corynespora cassiicola; P.C: Pseudoperonospora cubensis; F.G: Fusarium graminearum; R.S: Rhizoctonia
solani; B.C: Botrytis cinerea.
ACS Paragon Plus Environment