Design, Synthesis, and Antifungal Activities of Novel 1,2,4-Triazole Schiff Base Derivatives

Article abstract of DOI:10.1002/cbdv.201800263

With the aim to find new compounds with high antifungal activity, 21 4-amino-5-substituted-1,2,4-triazole Schiff bases (2a?–?2g, 3a?–?3g, and 4a?–?4g) were designed and synthesized. Their antifungal activities against Pythium solani, Gibberlla nicotiancola, Fusarium oxysporium f. sp. niveum, Gibberlla saubinetii, Alternaria iycopersici, Phytophthora capsici, Physalospora piricola, Cercospora arachidicola hori, and Fusarium oxysporium f. sp. cucumber were tested, parts of the compounds exhibited excellent antifungal activity. This research provides useful information for further study of antifungal agents.

Full text of DOI:10.1002/cbdv.201800263

Article Type: Full Paper
Design, Synthesis and Antifungal Activities of Novel 1,2,4-Triazole
Schiff Base Derivatives
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Ruyi Jin , Jingli Liu , Guanghui Zhang , Jiajia Li , Shuan Zhang , Hui Guo
aCollege of Pharmacy, Shaanxi University of Chinese Medicine, Shaanxi, China
Abstract: With the aim to find new compounds with high antifungal activity, 21
4-amino-5-substitute-1,2,4-triazole Schiff bases (2a-2g, 3a-3g and 4a-4g) were designed and
synthesized. Their antifungal activities against Pythium solani, Gibberlla nicotiancola, Fusarium
oxysporium f. sp. niveum, Gibberlla saubinetii, Alternaria iycopersici, Phytophthora capsici,
Physalospora piricola, Cercospora arachidicola hori, and Fusarium oxysporium f. sp. cucumber were
tested, parts of the compounds exhibited excellent antifungal activity. This research provides useful
information for further study of antifungal agents.
Keywords: synthesis; 1,2,4-triazole; Schiff base; antifungal activity
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through the copyediting, typesetting, pagination and proofreading process, which may lead to
differences between this version and the Version of Record. Please cite this article as doi:
10.1002/cbdv.201800263
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1. Introduction
1,2,4-Triazole derivatives due to their broad-spectrum activities have potential applications in
the fields of pesticides and medicines possessing antifungal[1], antibacterial[2], antitumor[3]
antitrypanosomal[4], antiproliferative[5] and antibiotics[6] properties. In recent years, 1,2,4-triazole
Schiff bases were found with good pharmacological activity[7-9] as well. In our previous research, a
large number of 4-amino-5-substitute-1,2,4-triazole Schiff bases were designed and synthesized.
Their biological activity showed parts of the compounds have excellent antifungal activity compared
with triadimefon[10-12], this result inspires us with passion to synthesize more 1,2,4-triazole Schiff
bases. Some research reported introducing heterocyclic skeleton into structure can enhance the
biological activity[13-15], on the basis of the above information, we designed and synthesized series of
1,2,4-triazole Schiff bases containing pyridine ring, imidazole ring and halogenated benzene ring,
respectively, expecting to find lead compound with higher antifungal
activity. Target compounds were synthesized via 4-amino-5-substitute-1,2,4-triazolethione with
This project was supported by the National Natural Science Foundation of China (No. 21373161)
Corresponding author. E-mail: jinruyi335588@163.com; guohui20032476@163.com;
substituted benzaldehyde using glacial acetic acid as catalyst and solvent. Their structures were
confirmed by IR, 1H NMR, 13C NMR, melting point, elemental analysis and mass spectra. In addition,
their antifungal activity against Pythium solani, Gibberlla nicotiancola, Fusarium oxysporium f. sp.
niveum, Gibberlla saubinetii, Alternaria iycopersici, Phytophthora capsici, Physalospora piricola,
Cercospora arachidicola hori, and Fusarium oxysporium f. sp. cucumber were tested.
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2. Results and Discussion
2.1 Synthesis and Characterization
The synthesis of compounds 2a-2g, 3a-3g, and 4a-4g were outlined in Scheme 1 and Scheme 2,
all the target compounds were first reported. The structure of title compounds was confirmed on
the basis of their spectral data. All spectral and analytical data were consistent with the assigned
structure. The bands observed near 2950 and 3050 cm-1 in the IR spectrum are assigned to the C–H
and N–H stretching modes, respectively. The strong peaks around 1560 cm−1 are ascribed to the C=N
group of Schiff base. The characteristic stretching vibrations v (C=S) appeared at around 1254 cm−1,
and there is no absorption at 2565-2550 cm-1 (S–H), manifesting title compounds are mainly exist in
keto configuration, and this result is in agreement with the previous research[11].
2.2 Antifungal activities
The tested fungi and antifungal activity results were listed in Table 1 and Table 2, respectively.
From Table 2, title compounds showed good, moderate, and week acticity, respectively. The
bioassay indicated the inhibition ratio of triadimefon to the fungi Pythium solani, Gibberlla
nicotiancola, Fusarium oxysporium f. sp. niveum, Gibberlla saubinetii, and Alternaria iycopersici, are
greater than 50 %. No matter triadimefon or title compounds, their antifungal activities against
Phytophthora capsici, Physalospora piricola, Cercospora arachidicola hori, and Fusarium oxysporium
f. sp. Cucumber are moderate or week. Then the title compounds against Pythium solani, Gibberlla
nicotiancola, Fusarium oxysporium f. sp. niveum, Gibberlla saubinetii, and Alternaria iycopersici were
listed separately in Fig.1. Compounds 2b, 2c, 2f, 2g, 3a, 4a, 4b, and 4e showed excellent activity
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against Pythium solani; compound 4a showed good activity against Gibberlla nicotiancola;
compounds 3a, 3b, 4a, 4b, and 4e showed good activty against Gibberlla saubinetii; compounds 2a
and 2f showed good activity against Alternaria iycopersici.
Generally, parts of the compounds exhibited excellent antifungal activity, the results showed
compounds 3a, 3b, 4a and 4b exhibited good activity against gibberlla nicotiancola, pythium solani
and fusarium oxysporium f. sp. niveum. Only compound 4a showed broad-spectrum antifungal
activity, which has the potential to be further researched as antifungal agent.
3. Conclusions
From the above results, it is concluded that, a series of novel 4-amino-5-substitute
-1,2,4-triazole Schiff bases have been prepared and evaluated antifungal activity. The activity test
showed compound 4a showed broad-spectrum antifungal activity, which has the potential to be
further researched as antifungal agent. This research provides a basic data for further investigation
of antifungal drugs.
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4. Experimental
4.1 Chemistry
Elemental analysis was performed with a Vario ELШ CHNOS analyzer; IR (KBr) spectra
was recorded on an IR-400 spectrophotomete; 1H NMR and 13C NMR spectra was measured with a
Varian unity INOVA-400 nuclear magnetic resonance using CDCl3 or DMSO as the solvent and TMS as
an internal standard; mass spectra was obtained from micrOTOF-Q II mass spectrometer; the
melting point was determined on MP3 melting point apparatus.
4.2 Synthesis
Compounds 1a-1g were prepared according to the literatures[10, 13-15]. Compounds 2a-2g, 3a-3g,
and 4a-4g were synthesized by compounds 1a-g and solution of absolute ethanol with 4-pyridine
benzaldehyde (5 mL), 3-bromo-6-hydroxy-2-methoxybenzaldehyde (5 mL) and 4-(1H-imidazol -1-yl)
benzaldehyde (5 mL) in the presence of glacial acetic acid (2 mL), the mixture was refluxed about 4
h, TLC monitors the reaction until all raw material disappeared, the crude products were purified by
DMF and Water (1:1).
(E)-5H-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2a): yield 75.3 %; yellow solid;
mp: 233.4-234.3 ℃; IR (KBr) v/cm-1: 3112, 2931, 1550, 1490, 1291, 925, 846, 685, 560; 1H NMR (400
MHz, (D6)DMSO) δ 9.58 (s, 1H); 9.00 (s, 1H); 8.79-8.80 (m, 2H); 7.79-7.80 (m, 2H); ESI–MS m/z:
206.0423 (M+H); Elemental Anal. C8H7N5S, Found (Calcd) %: C 46.99 (46.82), H 3.21 (3.44), N 34.09
(34.12).
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(E)-5-ethyl-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2b): yield 81.9 %; yellow
solid; mp: 250.5-252.0 ℃; IR (KBr) v/cm-1: 3050, 2940, 1548, 1487, 1254, 901, 788, 653, 562; 1H NMR
(400 MHz, (D) CDCl3) δ 10.85 (s , 1H); 10.57 (s, 1H); 8.79-8.81 (m, 2H), 7.71-7.72 (m, 2H), 2.88-2.90
(q, 2H), 1.36-1.38 (t, J = 7.2 Hz, 3H); 13C NMR (400MHz, (D6) DMSO) δ 11.2, 25.6, 120.1, 142.3, 148.7,
154.8, 157.9, 182.3; ESI–MS m/z: 234.2927 (M+H); Elemental Anal. C10H11N5S, Found (Calcd) %: C
51.49 (51.48), H 4.73 (4.75), N 30.03 (30.02).
(E)-5-propyl-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2c): yield 78.3 %; yellow
solid; mp: 234.0-236.0 ℃; IR (KBr) v/cm-1: 3130, 2960, 1561, 1481, 1240, 953, 842, 683; 1H NMR (400
MHz, (D) CDCl3) δ 11.02 (s, 1H), 10.85 (s, 1H), 8.79-8.82 (t, J = 8.0 Hz, 2H), 7.72-7.74 (m, 2H),
2.83-2.85 (t, J = 7.2 Hz, 2H), 1.81-1.82 (m, 2H), 1.04-1.06 (t, J = 7.2 Hz, 3H); ESI–MS m/z: 248.3195
(M+H); Elemental Anal. C11H13N5S, Found (Calcd) %: C 53.43 (53.42), H 5.31 (5.30), N 25.23 (25.25).
(E)-5-benzy-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2d): yield 80 %; yellow solid;
mp: 238.7-240.2 ℃; IR (KBr) v/cm-1: 3064, 2953, 1587, 1499, 1221, 967, 859, 693; 1H NMR (400 MHz,
(D6) DMSO) δ 10.35 (s, 1H), 8.77-8.79 (d, J = 7.2 Hz, 2H), 7.80-7.81 (m, 2H), 7.31 (m, 5H), 4.19 (s, 2H);
ESI–MS m/z: 296.3623 (M+H); Elemental Anal. C15H13N5S, Found (Calcd) %: C 61.01 (61.00), H 4.41
(4.44), N 23.73 (23.71).
(E)-5-(4-pridyl)-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2e): yield 77 %; yellow
solid; mp: > 275 ℃; IR (KBr) v/cm-1: 3056, 2932, 1583, 1454, 1280, 965, 841, 689; 1H NMR (400 MHz,
(D6) DMSO) 8.78 (s, 4H), 7.81 (s, 4H); ESI–MS m/z: 283.3236 (M+H); Elemental Anal. C13H10N6S,
Found (Calcd) %: C 55.29 (55.30), H 3.58 (3.57), N 29.76 (29.77).
(E)-5-(4-methylphenyl)-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2f): yield 84 %;
yellow solid; mp: 254.4-256.2 ℃. IR (KBr) v/cm-1: 3102, 2927, 1581, 1460, 1271, 1007, 839, 647. 1H
NMR (400 MHz, (D6) DMSO) δ 10.01 (s, 1H), 8.79-8.80 (m, 2H), 7.81-7.82 (m, 2H ), 7.74-7.46 (d, J =
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8.0 Hz, 2H), 7.35-7.37 (d, J = 8.0 Hz, 2H), 2.37 (s, 3H); ESI–MS m/z: 296.3624 (M+H); Elemental Anal.
C15H13N5S, Found (Calcd) %: C 60.99 (61.00), H 4.45 (4.44), N 23.70 (23.71).
(E)-5-(2-methoxylphenyl)-4-[(4-pyridyl)methyleneamino]-1,2,4-triazole-3-thione (2g): yield 74.3
%; yellow solid; mp: 240.6-242.4 ℃. IR (KBr) v/cm-1: 3103, 2920, 1576, 1456, 1281, 1017, 840, 695,
581; 1H NMR (400 MHz, (D6) DMSO) δ 9.96 (s, 1H), 8.72-8.73 (m, 2H), 7.66-7.67 (m, 2H), 7.52-7.58
(m, 2H), 7.15-7.17 (m, 2H), 3.65 (s, 3H); ESI–MS m/z: 312.3618 (M+H); Elemental Anal. C15H15N5OS,
Found (Calcd) %: C 57.86 (57.86), H 4.20 (4.21), N 22.50 (22.49).
(E)-5H-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-triazole-3-thione (3a):
yield 71.8 %; light brown solid; mp: 276.2-277.8 ℃; IR (KBr) v/cm-1: 3424, 3139, 2998, 1618, 1569,
1439, 1226, 1128, 897, 656; 1H NMR (400 MHz, (D6) DMSO) δ 10.37 (s, 1H), 10.12 (s, 1H), 7.59 (s,
1H), 7.31(s, 1H) 3.89 (s, 3H); ESI–MS m/z: 328.9612 (M+H); Elemental Anal. C10H9BrN4O2S, Found
(Calcd) %: C 36.81 (36.49), H 2.33 (2.76), N 17.46 (17.02).
(E)-5-ethyl-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-triazole-3-thione
(3b): yield 74.5 %; light brown solid, mp: 269.5-270.3℃; IR (KBr) v/cm-1: 3425, 3135, 2994, 1618,
1569, 1439, 1226, 1128, 897, 655; 1H NMR (400 MHz, (D6) DMSO) δ 10.31(s, 1H), 10.06 (s, 1H), 7.52
(s, 1H), 7.25 (s, 1H), 3.83 (s, 3H), 2.67-2.71 (q, 2H), 1.14-1.18 (t, J = 8.0 Hz, 3H); 13C NMR (400 MHz,
(D6) DMSO) δ 10.8, 23.9, 103.9, 111.7, 116.8, 136.4, 144.2, 157.8, 162.5, 163.5, 182.1; ESI–MS m/z:
356.9903 (M+H); Elemental Anal. C12H13BrN4O2S, Found (Calcd) %: C 40.11 (40.35), H 3.42 (3.67), N
15.76 (15.68).
(E)-5-propyl-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-triazole-3-thione
(3c): yield 73.3 %; light brown solid; mp: 266.7-268.4 ℃; IR (KBr) v/cm-1: 3425, 3131, 2994, 1618,
1565, 1482, 1228, 1129, 898, 653; 1H NMR (400 MHz, (D6) DMSO) δ 10.43 (1H, s), 10.17 (1H, s), 7.64
(s, 1H), 7.38 (s, 1H), 3.96 (s, 3H), 2.79-2.81 (t, J = 8.0 Hz, 2H), 1.71-1.71 (m, 2H), 1.00-1.04 (t, J = 8.0
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Hz, 3H); ESI–MS m/z: 371.0054 (M+H); Elemental Anal. C13H15BrN4O2S, Found (Calcd) %: C 42.33
(42.06), H 4.22 (4.27), N 15.36 (15.09).
(E)-5-benzy-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-triazole-3-thion
e (3d): yield 71.4 %; light brown solid; mp: 272.4-274.5 ℃; IR (KBr) v/cm-1: 3425, 3131, 2994, 1618,
1565, 1482, 1228, 1129, 898, 653; 1H NMR (400 MHz, (D6) DMSO) δ 10.40 (s, 1H), 10.04 (s, 1H),
7.49(s, 1H), 7.28-7.34 (m, 6H), 4.16 (s, 3H), 3.88 (s, 3H); ESI–MS m/z: 419.0063 (M+H); Elemental
Anal. C17H15BrN4O2S, Found (Calcd) %: C 48.35 (48.70), H 3.78 (3.61), N 13.56 (13.36).
(E)-5-(4-pridyl)-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-triazole-3-
thione (3e): yield 62.3 %; light brown solid; mp: 161.5-162.3 ℃. IR (KBr) v/cm-1: 3424, 3131, 2993,
1617, 1566, 1483, 1224, 1129, 898, 653; 1H NMR (400 MHz, (D6) DMSO) δ 10.26 (s, 1H), 10.11 (s,
1H), 8.82-8.83 (m, 2H), 7.89-7.90(m, 2H), 7.56-7.58 (m, 1H), 7.41 (m, 1H), 3.95 (s, 3H); ESI–MS m/z:
405.9854 (M+H); Elemental Anal. C15H12BrN5O2S, Found (Calcd) %: C 44.65 (44.35), H 2.78 (2.98), N
17.46 (17.24).
(E)-5-(4-methylphenyl)-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-
triazole-3-thione (3f): yield 75.3 %; light brown solid; mp: 266.2-267.8 ℃; IR (KBr) v/cm-1: 3423,
3132, 2990, 1615, 1568, 1486, 1223, 1128, 899, 653; 1H NMR (400 MHz, (D6) DMSO) δ 10.19 (s,
1H), 10.03 (s, 1H), 7.72-7.73 (m, 2H), 7.46-7.48 (m, 1H), 7.33-7.36 (m, 3H), 3.89 (s, 3H), 2.37 (s, 3H);
ESI–MS m/z: 419.0067 (M+H); Elemental Anal. C17H15BrN4O2S, Found (Calcd) %: C 44.65 (44.35), H
2.78 (2.98), N 17.46 (17.24).
(E)-5-(2-methoxylphenyl)-4-[(3-bromo-6-hydroxy-2-methoxyphenyl)methyleneamino]-1,2,4-
triazole-3-thione (3g): yield 63.5 %; light brown solid; mp: 248.2-250.1 ℃. IR (KBr) v/cm-1: 3424,
3131, 2993, 1617, 1566, 1483, 1224, 1129, 898, 653; 1H NMR (400 MHz, (D6) DMSO) δ 10.18 (s, 1H),
9.95 (s, 1H), 7.56-7.60 (m, 1H), 7.48-7.50 (d, J = 8 Hz, 1H), 7.25-7.27 (d, J = 8 Hz, 2H), 7.16-7.18 (d, J =
8 Hz, 1H), 7.08-7.12 (m, 1H), 3.86 (s, 3H), 3.68 (s, 3H); ESI–MS m/z: 435.0050 (M+H); Elemental Anal.
C17H15BrN4O3S, Found (Calcd) %: C 46.75 (46.91), H 3.42 (3.47), N 12.54 (12.87).
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(E)-5-H-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione (4a): yield 65.5 %;
light yellow solid; mp: 259.4-261.3 ℃; IR (KBr) v/cm-1: 3119, 2905, 1578, 1472, 1263, 1018, 865,
637; 1H NMR (400 MHz, (D6) DMSO) δ 14.06 (s, 1H), 9.60 (s, 1H), 9.03 (s, 1H), 8.81-8.83 (d, J = 8.0 Hz,
2H), 7.81-7.83 (d, J = 8.0 Hz, 2H); ESI–MS m/z: 271.0689 (M+H); Elemental Anal. C12H10N6S, Found
(Calcd) %: C 53.63 (53.32), H 3.53 (3.33), N 31.33 (31.09).
(E)-5-ethyl-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione (4b): yield 64.5
%; light yellow solid; mp: 228.5-230.2 ℃; IR (KBr) v/cm-1: 3198, 2964, 1578, 1463, 1281, 1018, 849,
663; 1H NMR (400 MHz, (D6) DMSO) δ 10.02 (s, 1H), 8.44 (s, 1H), 8.04-8.06 (d, J=8.0 Hz, 2H),
8.87-8.89(d, J = 8.0 Hz, 2H), 7.16 (s, 1H), 2.75-2.77 (q, 2H), 1.21-1.25 (t, J = 8.0 Hz, 3H); 13C NMR (400
MHz, DMSO-d6) δ 11.2, 25.1, 118.4, 130.2, 130.5, 130.6, 133.5, 135.9, 139.6, 154.6, 157.2, 181.4;
ESI–MS m/z: 299.1022 (M+H); Elemental Anal. C14H14N6S, Found (Calcd) %: C 56.43 (56.36), H 4.94
(4.73), N 28.32 (28.33).
(E)-5-propyl-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione (4c): yield 67.1
%; light yellow solid; mp: 241.2-242.1 ℃; IR (KBr) v/cm-1: 3109, 2934, 1587, 1483, 1229, 1010, 840,
689; 1H NMR (400MHz, (D6) DMSO) δ 10.03 (s, 1H), 8.45 (s, 1H), 8.05-8.06 (m, 2H), 7.89-7.91 (m, 3H),
7.18 (s, 1H), 2.72-2.76 (t, J = 8.0 Hz, 2H), 1.68-1.72 (m, 2H), 0.93-0.95 (t, J=7.2 Hz, 3H); ESI–MS m/z:
313.1143 (M+H); Elemental Anal. C15H16N6S, Found (Calcd) %: C 57.43 (57.67), H 5.34 (5.16), N 26.56
(26.90).
(E)-5-benzy-2,4-dihydro-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione
(4d): yield 73.3 %; light yellow solid; mp: 260.1-261.5 ℃. IR (KBr) v/cm-1: 3237, 2965, 1598, 1479,
1282, 1017, 858, 698; 1H NMR (400MHz, (D6) DMSO) δ 14.01 (s, 1H), 10.35 (s, 1H), 8.77-8.79 (d, J =
8.0 Hz, 2H), 7.80-7.81 (d, J = 7.4 Hz, 2H), 7.32-7.31(d, J = 7.2 Hz, 4H), 7.22-7.26 (m, 1H), 4.20 (2H, s);
ESI–MS m/z: 361.1137 (M+H); Elemental Anal. C19H16N6S, Found (Calcd) %: C 63.56 (63.31), H 4.32
(4.47), N 23.55 (23.32).
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(E)-5-(4-pridyl)-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione (4e): yield
79.3 %; light yellow solid; mp: 260.1-261.5 ℃; IR (KBr) v/cm-1: 3031, 2965, 1600, 1476, 1283, 1027,
848, 688；1H NMR (400MHz, (D6) DMSO) δ 8.77 (3H, s), 8.03 (3H, s), 5.86(3H, s); ESI–MS m/z:
348.0934 (M+H); Elemental Anal. C17H13N7S, Found (Calcd) %: C 58.56 (58.77), H 3.63 (3.77), N 28.76
(28.22).
(E)-5-(4-methylphenyl)-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione (4f):
yield 74.1 %; light yellow solid; mp: 236.2-238.1℃; IR (KBr) v/cm-1: 3033, 2965, 1598, 1476, 1282,
1017, 848, 687; 1H NMR (400MHz, (D6) DMSO) δ 10.01 (s, 1H), 8.79-8.80 (d, J = 7.2 Hz, 2H), 7.81-7.82
(m, 3H), 7.74-7.76 (m, 3H), 7.35-7.37 (d, J = 8.0 Hz, 3H), 2.37 (3H, s); ESI–MS m/z: 361.1133 (M+H);
Elemental Anal. C19H16N6S, Found (Calcd) %: C 63.16 (63.31), H 4.29 (4.47), N 23.18 (23.32).
(E)-5-(2-methoxylphenyl)-4-[(4-(1H-imidazol)phenyl)methyleneamino]-1,2,4-triazole-3-thione
(4g): yield 71.4 %; light yellow solid; mp: 250.2-251.3 ℃; IR (KBr) v/cm-1: 3056, 2965, 1597, 1474,
1283, 1017, 848, 688, 642; 1H NMR (400MHz, (D6) DMSO) δ 9.65 (s, 1H), 8.40 (s, 2H), 7.86-7.89 (m,
2H), 7.81-7.83 (m, 3H), 7.50-7.56 (m, 2H), 7.13-7.15 (m, 4H), 3.66 (s, 3H); ESI–MS m/z: 337.1109
(M+H); Elemental Anal. C19H16N6OS, Found (Calcd) %: C 60.45 (60.62), H 4.54 (4.28), N 22.56 (22.33).
4.3 Antifungal activities
The antifungal activities of all target compounds were evaluated against pathogenic fungi,
containing pythium solani, gibberlla nicotiancola, fusarium oxysporium f. sp. niveum, gibberlla
saubinetii, alternaria iycopersici, phytophthora capsici, physalospora piricola, cercospora arachidicola
hori, and fusarium oxysporium f. sp. cucumber, which are often encountered in plants. Triadimefon
was used as positive control. The plants pathogenic fungi were provided by Microbiology Institute of
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Shaanxi and triadimefon was purchased from Jiangsu Sevencontinent Green Chemical Co., Ltd.,. The
antifungal activity test method and data-processing method were according to the literature[16-17]
.
Acknowledgements
The authors are grateful to the National Natural Science Foundation of China (No.21373161) for
its financial support for this project.
Author Contribution Statement
Jingli Liu, Guanghui Zhang, Jiajia Li and Shuan Zhang performed the experiments, Hui Guo
contributed reagents and analysis tools. Ruyi Jin designed the experiments, analyzed the data, and
wrote the paper.
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Table 1. Pathogens fungi for test
Number
Pathogens fungi
A
B
C
D
E
F
Gibberlla nicotiancola
Pythium solani
Gibberlla saubinetii
Fusarium oxysporium f.sp. niveum
Alternaria iycopersici
Phytophthora capsici
G
H
I
Fusarium oxysporium f.sp. cucumber
Cercospora arachidicola hori
Physalospora piricola
Table 2. The antifungal results of the compounds II33-48 to nine pathogens at 50 ug·mL-1 (%)
Compound
s
A
B
C
D
E
F
G
H
I
2a
2b
2c
2d
2e
2f
42.6
68.3
70.1
58.5
28.2
68.1
63.4
10.2
58.7
65.7
60.3
34.5
69.5
72.8
3.4
31.2
53.6
60.2
56.2
40.2
69.2
73.9
57.3
46.5
33.7
34.6
44.7
56.3
48.2
52.3
46.1
38.2
36.9
32.1
48.2
46.3
33.1
34.5
32.9
28.9
26.8
33.9
35.5
28.9
43.2
33.2
24.5
26.8
31.2
34.8
42.1
33.9
32.1
28.9
20.9
38.3
40.8
38.5
25.6
57.9
36.3
56.3
32.3
2g
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3a
59.2
56.1
45.2
33.8
38.9
45.3
46.7
66.8
62.3
45.3
38.9
60.5
72.1
30.7
56.2
67.8
65.2
56.3
48.9
63.2
78.2
67.1
82.8
76.4
65.2
54.6
76.3
69.9
40.2
80.3
28.1
18.8
12.5
46.9
46.9
43.8
46.9
27.5
18.8
12.5
12.5
18.8
25.0
12.5
71.9
79.4
77.3
54.2
56.1
60.4
70.3
77.6
83.6
80.9
62.3
50.1
60.7
78.3
50.3
82.5
29.4
23.5
17.6
23.5
23.5
23.5
35.3
15.7
23.5
29.4
29.4
11.8
23.5
35.3
52.9
38.7
35.5
35.5
32.3
38.7
32.3
41.9
36.7
41.9
45.2
45.2
29.0
41.9
45.2
41.9
9.5
9.5
9.5
0.0
0.0
9.5
4.8
9.5
9.5
4.8
4.8
19.0
33.3
9.5
47.6
14.3
35.7
0.0
38.5
30.8
26.9
23.1
26.9
26.9
19.2
19.2
19.2
19.2
46.2
50.0
69.2
30.8
34.6
3b
3c
3d
0.0
3e
14.3
14.3
14.3
7.1
3f
3g
4a
4b
0.0
4c
0.0
4d
0.0
4e
4f
28.6
57.1
14.3
21.4
4g
Triadimefon
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Fig.1 The inhibition ratio of title compounds against fungi A, B, C, D, and E at 50 ug•mL-1 (%)
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