Journal of Agricultural and Food Chemistry
Article
All other solvents and chemicals were of reagent grade and used
without further purification.
thoroughly in a Petri dish. The PDA medium was thoroughly mixed by
turning around the Petri dish in a sterilized operation desk 5 times to
scatter the compounds in PDA evenly. After that, the fungi cake was
inoculated on the plate and incubated in the culture tank at 24−26 °C.
Distilled water was used as the control or check (CK). The diameter of
fungal spread was measured after 2 days. Growth inhibition was then
calculated using the corresponding control. Microorganisms used in this
study included Pyricularia oryzae, Bipolaris maydis, Colletotrichum
lagenarium, and Xanthomonas oryzae.
System Acquired Resistance Screening. After direct antimicrobial
activity screening, the SAR activity was determined as well. In order to
screen out the new compounds effectively, the screening was
conducted in three steps. In the first screening, all compounds were
tested with comparatively high concentrations to avoid skipping any
potential active compounds. After that, compounds with potential SAR
activity were tested with lower concentration in the second assay
screening to screen out compounds with high activity. Furthermore,
the compounds with high activity and facile preparation were chosen
for field tests to exploit their agricultural applications.
Field tests were carried out in four locations including Beijing (two
sites), Liaoning province, and Shandong province during two years.
Synthesis of Compounds 3b−3e and 5a−5m. The start-
ing compound 1 was synthesized according to the literature description.19
The synthesis of compound 3c and the general synthetic procedures of
other test compounds were described in our previous work, along with
the detailed physical properties and structural data of compounds
3b−3e and 5a−5d.17 Data of earlier unreported compounds were
described, as shown in Tables 1 and 2.
Biological Assay Screening. The antimicrobial activity and the
SAR activity of the target compounds were evaluated according to the
following procedures.
Antimicrobial Activity Screening. A stock solution of each com-
pound was prepared by dissolving the compound in N,N-dimethyl-
formamide (DMF) to form a concentration of 1000 mg/L. Then a
working solution of 100 mg/L was prepared by mixing 1 mL of the
stock solution with 9 mL of potato dextrose agar (PDA) culture media
Table 1. Yield, Melting Point, IR, and Elemental Analysis Data of the Target Compounds
elemental analysis
N
requires
found
H
compd
yield (%)
mp (°C)
IR (cm−1
)
C
H
C
N
5e
5f
55
56
60
57
88−89
84−85
112−113
76−78
ν 1715, 1300, 1100, 780
ν 1720, 1300, 1105, 785
ν 1715, 1300, 1100
55.49
44.22
42.53
55.49
3.20
2.73
2.44
3.20
8.09
6.88
6.17
8.09
55.35
47.49
42.53
55.74
3.35
2.80
2.53
3.18
8.17
6.94
6.18
8.18
5g
5h
ν 3089, 2950, 1720, 1599, 1503, 1406,
1265, 1130, 1095, 1045, 870, 700
5i
5j
5k
57
52
52
100−102
101−103
125−127
ν 3089, 2955, 1707, 1592, 1558, 1488, 1406,
1272, 1205, 1130, 1080, 860, 805, 760, 680
ν 3119, 2956, 1733, 1603, 1521, 1430,
1340, 1268, 1120, 1060, 860, 770, 720
ν 3089, 2963, 1710, 1636, 1562, 1495, 1400,
1295, 1370, 1030, 980, 840, 756, 680
ν 1710, 1310, 1100, 770
52.97
51.47
61.01
3.06
2.97
3.98
7.72
11.26
7.90
53.20
51.69
61.22
3.10
3.10
3.90
7.71
11.17
8.02
5l
50
56
92−93
119−120
57.03
47.79
3.94
2.83
7.82
6.55
57.03
47.90
4.03
2.58
8.20
6.36
5m
ν 3059, 2955, 1766, 1703, 1558, 1484,
1410, 1298, 1180, 1087, 900, 810, 770, 720
1
Table 2. H NMR and HRMS/MS Data of the Target Compounds
compd
1H NMR (solvent: DMSO-d6)
HRMS/MS (EI)
[M+], 346.04; found, 346.00
5e
δ 4.69−4.76 (m, 4H, OCH2CH2O), 7.22 (t, 1H, J = 7.5, Ar−H), 7.22 (t, 1H, J = 8.6 Hz, Ar−H),
7.50−7.53 (m, 1H, Ar−H), 7.78 (t, 1H, J = 7.8 Hz, Ar−H), 7.94 (td, 1H, J1 = 7.5, J2 = 1.5, Ar−H), 8.47
(d, 1H, J = 7.3 Hz, Ar−H), 8.88 (d, 1H, J = 7.3, Ar−H)
5f
δ 4.67−4.76 (m, 4H, OCH2CH2O), 7.52−7.56 (m, 2H, Ar−H), 7.77−7.80 (m, 1H, Ar−H), 7.78−7.86
(m, 1H, Ar−H), 8.02 (t, 1H, J = 7.8 Hz, Ar−H), 8.54 (d, 1H, J = 7.3 Hz, Ar−H), 9.12 (d, 1H,
J = 8.4 Hz, Ar−H)
[M+], 407.96; found (M-N2), 380.00
5g
δ 4.69−4.76 (m, 4H, OCH2CH2O), 7.1−7.2 (m, 1H, Ar−H), 7.48 (t, 1H, J = 7.4 Hz, Ar−H), 7.75 (dd,
1H, J1 = 7.7 Hz, J2 = 1.4 Hz, Ar−H), 7.96 (t, 1H, J = 7.7 Hz, Ar−H), 7.99 (t, 1H, J = 7.7 Hz, Ar−H),
8.48 (d, 1H, J = 7.3 Hz, Ar−H), 9.04 (d, 1H, J = 8.2 Hz, Ar−H)
HRMS [M+], 453.9490; found, 453.9484
5h
5i
δ 4.67−4.79 (m, 4H, OCH2CH2O), 7.31−7.35 (m, 2H, Ar−H), 7.94 (dd, 1H, J1 = 7.8 Hz, J2 = 7.3 Hz,
Ar−H), 8.01−8.05 (m, 2H, Ar−H), 8.44 (d, 1H, J = 7.3 Hz, Ar−H), 9.04 (d, 1H, J = 7.8 Hz, Ar−H)
HRMS [M+], 346.0424; found, 346.0389
HRMS [M+], 362.0128; found, 362.0128
δ 4.68−4.79 (m, 4H, OCH2CH2O), 7.57 (d, 2H, J = 8.5 Hz, Ar−H), 7.94 (dd, 1H, J1 = 8.3 Hz,
J2 = 7.3 Hz, Ar−H), 7.96 (d, 2H, J = 8.5 Hz, Ar−H), 8.44 (d, 1H, J = 7.3 Hz, Ar−H), 9.04 (d, 1H,
J = 8.3 Hz, Ar−H)
5j
δ 4.74−4.80 (m, 4H, OCH2CH2O), 7.94 (dd, 1H, J1 = 7.3 Hz, J2 = 8.4 Hz, Ar−H), 8.19 (d, 2H, J = 8.6
Hz, Ar−H), 8.32 (d, 2H, J = 8.6 Hz, Ar−H), 8.43−8.45 (d, 1H, J = 7.3 Hz, Ar−H), 9.02−9.04 (d, 1H,
J = 8.4 Hz, Ar−H)
[M+], 373.04; found, 373.10
5k
δ 4.56−4.70 (m, 4H, OCH2CH2O), 6.68 (d, 1H, J = 16.0 Hz, =CH−), 7.36−7.42(m, 3H, Ar−H),
7.65−7.69 (m, 3H, =CH- and Ar−H), 7.94 (dd, 1H, J1 = 7.3 Hz, J2 = 8.2 Hz, Ar−H), 8.44 (d, 1H,
J = 7.3 Hz, Ar−H), 9.03 (d, 1H, J = 8.2 Hz, Ar−H)
HRMS [M+], 354.0674; found, 354.0659
5l
δ 4.69−4.78 (m, 4H, OCH2CH2O), 6.98−7.00 (m, 2H, Ar−H), 7.78 (t, 1H, J = 7.8 Hz, Ar−H), 7.83 (dd,
1H, J1 = 7.9 Hz, J2 = 1.8 Hz, Ar−H), 8.44 (d, 1H, J = 7.3 Hz, Ar−H), 8.86 (d, 1H, J = 8.2 Hz, Ar−H)
HRMS [M+], 358.0599; found, 358.0623
[M+], 425.98; found, 426.00
5m
δ 4.55−4.64 (m, 4H, OCH2CH2O), 4.99 (s, 2H, CH2), 7.06 (d, 1H, J = 9.0 Hz, Ar−H), 7.13 (d, 1H,
J = 8.9 Hz, Ar−H), 7.42 (s, 1H, Ar−H), 7.93 (dd, 1H, J1 = 8.3 Hz, J2 = 7.3 Hz, Ar−H), 8.35 (d, 1H,
J = 7.3 Hz, Ar−H), 9.05 (d, 1H, J = 8.3 Hz, Ar−H)
347
dx.doi.org/10.1021/jf203974p | J. Agric.Food Chem. 2012, 60, 346−353