Synthesis, crystal structure, and biological activity of 4-methyl-1,2,3-thiadiazole-containing 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles

Article abstract of DOI:10.1021/jf9029628

Heterocyclic compounds play an important role as the main sources of lead molecules of agrochemicals. Synthesis and biological activity of thiadiazole-containing 1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles were seldom reported. To find novel lead compounds with various biological activities, a series of 6-substituted-3-(4-methyl-1,2,3-thiadiazolyl)[1,2,4]triazolo[3,4-b][1, 3,4]thiadizoles were rationally designed and synthesized according to the principle of combinations of bioactive substructures by the condensation of 3-(4-methyl-1,2,3-thiadiazolyl)-4-amino-1,2,4-triazole-5-thione with various carboxylic acids and phosphorus oxychloride. All newly synthesized compounds were identified by proton nuclear magnetic resonance (¹H NMR), infrared spectroscopy (IR), electroionization mass spectrometry (EI/MS), and elementary analysis. The crystal structure of 3-(4-methyl-1,2,3-thiadiazolyl)-6- (4-methylphenyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizole was determined by X-ray diffraction crystallography. In this crystal, two intermolecular hydrogen bonds (N2- ? -H-C12 and N3... H-C13), a weak intermolecular interaction (S...S), and the weak pπ-pπ intermolecular interaction were observed. Fungicide screening indicated that all of the target compounds showed certain extent of growth inhibition against fungi tested. 3-(4Methyl-1,2,3-thiadiazolyl) -6-n-propyl[1,2,4]triazolo[3,4-6][1,3,4]thiadizole and 3-(4-methyl-1,2,3- thiadiazolyl)-6-trichloromethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole were found to have potential wide spectrum of fungicide activity. The median effective concentrations (EC₅₀) detected for 3-(4-methyl-1,2, 3thiadiazolyl)-6-trichloromethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole to six fungi were from 7.28 μmol/L against Pelicularia sasakii (Shirai) to 42.49 μmol/L against Alternaria solan!. The results indicated that thiadiazolecontaining 1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles were potential fungicide lead compounds.

Full text of DOI:10.1021/jf9029628

2630 J. Agric. Food Chem. 2010, 58, 2630–2636
DOI:10.1021/jf9029628
Synthesis, Crystal Structure, and Biological Activity
of 4-Methyl-1,2,3-thiadiazole-Containing
1,2,4-Triazolo[3,4-b][1,3,4]thiadiazoles†
Z
HIJIN
F
AN,*,||
Z
HIKUN
Y
ANG,|| HAIKE
UO, QINGXIANG
Z
Z
HANG,|| N
A
M
I
, HUAN
W
ANG, FEI
CAI,
X
IANG
Z
HENG
,
AND
HAIBIN
SONG
State Key Laboratory of Elemento-Organic Chemistry, Nankai University, No. 94 Weijin Road, Nankai
District, Tianjin 300071, People’s Republic of China. || These authors contributed equally to this work.
Heterocyclic compounds play an important role as the main sources of lead molecules of agrochemi-
cals. Synthesis and biological activity of thiadiazole-containing 1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles
were seldom reported. To find novel lead compounds with various biological activities, a series of
6-substituted-3-(4-methyl-1,2,3-thiadiazolyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizoles were rationally designed
and synthesized according to the principle of combinations of bioactive substructures by the condensa-
tion of 3-(4-methyl-1,2,3-thiadiazolyl)-4-amino-1,2,4-triazole-5-thione with various carboxylic acids and
phosphorus oxychloride. All newly synthesized compounds were identified by proton nuclear magnetic
resonance (1H NMR), infrared spectroscopy (IR), electroionization mass spectrometry (EI/MS), and
elementary analysis. The crystal structure of 3-(4-methyl-1,2,3-thiadiazolyl)-6-(4-methylphenyl)-
[1,2,4]triazolo[3,4-b][1,3,4]thiadizole was determined by X-ray diffraction crystallography. In this crystal,
two intermolecular hydrogen bonds (N2 H-C12 and N3 H-C13), a weak intermolecular interaction
3 3 3
3 3 3
(S S), and the weak pπ-pπ intermolecular interaction were observed. Fungicide screening indicated
3 3 3
that all of the target compounds showed certain extent of growth inhibition against fungi tested. 3-(4-
Methyl-1,2,3-thiadiazolyl)-6-n-propyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole and 3-(4-methyl-1,2,3-thiadia-
zolyl)-6-trichloromethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole were found to have potential wide spectrum
of fungicide activity. The median effective concentrations (EC50) detected for 3-(4-methyl-1,2,3-
thiadiazolyl)-6-trichloromethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole to six fungi were from 7.28 μmol/L against
Pellicularia sasakii (Shirai) to 42.49 μmol/L against Alternaria solani. The results indicated that thiadiazole-
containing 1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles were potential fungicide lead compounds.
KEYWORDS: 1,2,4-Triazolo[3,4-b][1,3,4]thiadiazole; 4-methyl-1,2,3-thiadiazole; fungicide bioassay;
systemic acquired resistance
INTRODUCTION
antifungal, antibacterial, antitubercular, anticancer, and analgesic
activities have been reported (8-12). The compounds bearing a
1,2,3-thiadiazole group possess versatile biological activities, in-
cluding anti-inflammatory, antitumor, hypotensive, antibacterial,
and antiallergic (13-16). Especially, some 1,2,3-thiadiazole deri-
vatives could be plant activators (17-20). Plant activators have
little or no direct antimicrobial activity in vitro, but they can induce
systemic acquired resistance to the broad spectrum of succeeding
pathogens attacking as in the biological, biochemical, and physio-
logical levels. There are two commercialized plant activators con-
taining a 1,2,3-thiadiazole group; they are acibenzolar-S-methyl
(BTH) (21, 22) and tiadinil (TDL) (23). In addition, 1,2,3-
thiadiazoles are widely used as synthons in organic synthesis (24).
Our group has focused attention on the synthesis and character-
ization of various 1,2,3-thiadiazole derivatives and their biological
activities. We have explored series of thiazole- and oxadiazole-
containing thiadiazole derivatives that displayed good systemic
acquired resistance to tobacco against TMV and certain degree
of fungus growth inhibition in vitro or in vivo (25). Prompted by
Most heterocyclic compounds extensively studied and reported
with pesticide activities are N- or S-containing heterocycles.
Among the N- or S-containing five-membered heterocyclic com-
pounds, some triazoles, thiazoles, and thiadiazoles have been
commercialized as agrochemicals all over the world (1-4). How-
ever, thiadiazole-containing 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles
were seldom reported with biological activity. The chemistry of
triazoles and their derivatives has always been the highlight of
study in lead compound discovery and biological screening (5, 6).
A triazolothiadiazole system may be viewed as a cyclic analogue of
two very important components, biguanide and thiosemicarba-
zide, which often displayed diverse biological activities (7). The
1,2,4-triazolo[3,4-b][1,3,4]thiadiazole ring systems have been well
studied, and so far a variety of biological activities including
†Part of the ECUST-Qian Pesticide Cluster.
*Address correspondence to this author (telephone þ86-22-23504367;
fax þ86-22-23505948; e-mail fanzj@nankai.edu.cn).
pubs.acs.org/JAFC
Published on Web 12/16/2009
© 2009 American Chemical Society

Article
J. Agric. Food Chem., Vol. 58, No. 5, 2010 2631
Scheme 1. Synthesis Routine for the Target Compounds
these observations, here we designed and synthesized a series of
6-substituted-3-(4-methyl-1,2,3-thiadiazolyl)[1,2,4]triazolo[3,4-b]-
[1,3,4]thiadizoles 5 according to the principle of combinations of
bioactive substructures (Scheme 1). The main differences between
this study and our former studies existed in the heterocyclic
moieties combined with bioactive substructure 4-methyl-1,2,3-
thiadiazole: our former studies introduced thiazole- and oxadia-
zole as monocyclic moieties into the target compounds (25); this
study introduced the fused heterocyclic moiety 1,2,4-triazolo[3,4-b]-
[1,3,4]thiadizole into the target compounds. The novel struct-
ures synthesized here were confirmed by elemental analysis, IR,
1H NMR, and MS; their biological activities were also detected.
Our results also indicate that attachment of the 4-methyl-1,2,3-
thiadiazole group to the 3-position of the [1,2,4]triazolo[3,4-b]-
[1,3,4]thiadizoles can change their biological activities. This kind
of molecule was a potential fungicide lead compound.
stirred vigorously for 0.5 h at room temperature, the mixture was filtered,
and the solid was washed with cold methanol. After drying, the solid was
recrystallized from methanol to give intermediate 2.
Preparation of 3-(4-Methyl-1,2,3-thiadiazolyl)-4-amino-1,2,4-
triazole-5-thione (4). The procedures were improved according to the
method in the literature (27). 4-Methyl-1,2,3-thiadiazole-5-carboxylic acid
hydrazide (2, 20 g, 83 mmol) was mixed with a solution of potassium
hydroxide (6.4 g, 125 mmol) in methanol (50 mL) at 0-5 °C under stirring.
Then, carbon disulfide (9.6 g, 125 mmol) was added dropwise, and the
reaction mixture was stirred for 12 h at room temperature. The solid
product of potassium dithiocarbazinate (3) was collected by filtration and
washed with chilled methanol. After drying, it was used for the next
reaction directly without purification. The above potassium dithiocarba-
zinate (3) was taken into hydrazine hydrate (200 mmol) and refluxed for
4 h, and the reaction mixture was then diluted with cold water and acidified
with concentrated hydrochloric acid. The white precipitate was filtered
and collected for washing withcold water and recrystallized from methanol
with a yield of 64%: mp 200-201 °C; 1H NMR (DMSO-d6, 300 MHz)
δ 14.34 (1H, s, NH), 6.08 (2H, s, NH2), 2.95 (3H, s, thiadiazolyl-CH3).
General Procedures for the Synthesis of 6-Substituted-3-(4-
methyl-1,2,3-thiadiazolyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizoles (5).
The procedures were carried out and revised according to ref 28. A mix-
ture of 3-(4-methyl-1,2,3-thiadiazolyl)-4-amino-1,2,4-triazole-5-thione (4,
1 mmol) and substituted carboxylic acid (1.1 mmol) in POCl3 (5 mL) was
refluxed for 5-6 h. The reaction mixture was then slowly poured into
crushed ice with vigorous stirring and neutralized with sodium bicarbo-
nate. The solids were filtered and collected for further purification by
washing with cold water and recrystallization from DMSO.
EXPERIMENTAL METHODS
Equipment for Structural Characterization. Melting points of all
compounds were determined on an X-4 binocular microscope (Gongyi
Technical Instrument Co., Henan, China), and the thermometer was not
corrected. Proton NMR spectra were obtained using a Bruker AC-P 300
spectrometer, and chemical shift values (δ) were reported as parts per
million with deuteruated dimethyl sulfoxide (DMSO-d6) as the solvent and
tetramethylsilane (TMS) as the internal standard. Elemental analyses were
determined on a Yanaca CHN Corder MT-3 elemental analyzer. IR was
recorded on a Bruker Vector 22 FTIR spectrometer using a KBr pellet
press. A Thermo Finnigan HPLC-MS/MS, Surveyor HPLC was equipped
with a Diamonsil C18, 4.6 ꢀ 250 mm, stainless column and LCQ
Advantage MS with ESI. The single-crystal structure for X-ray diffraction
was performed with a Bruker Smart 1000 CCD diffractometer. All
solvents and liquid reagents were of analytical reagent grade and were
dried in advance and distilled before use. Column chromatography
purification was carried out using silica gel.
Data for 5a: pale yellow crystal; yield, 63%; mp 231-232 °C; IR (KBr)
υ (cm-1) 3077, 2931, 1600, 1579, 1506, 1438, 1254, 1013, 956, 762; 1H
NMR (DMSO-d6, 300 MHz) δ 8.28 (1H, d, 3JHH = 7.8 Hz, benzene-H),
3
3
7.70 (1H, t, JHH = 7.2 Hz, benzene-H), 7.38 (1H, d, JHH = 8.4 Hz,
3
benzene-H), 7.26 (1H, t, JHH = 7.8 Hz, benzene-H), 4.09 (3H, s,
Ar-OCH3), 3.11 (3H, s, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative
intensity) 330 (Mþ, 2), 302 (100), 258 (5), 169 (14), 126 (52), 83 (63),
45 (28), 39 (46). Anal. Calcd for C13H10N6OS2: C, 47.26; H, 3.05; N, 25.44.
Found: C, 47.44; H, 3.19; N, 25.23.
Preparation of 4-Methyl-1,2,3-thiadiazole-5-carboxylic Acid
Hydrazide (2). Intermediate 4-methyl-1,2,3-thiadiazole-5-carboxylic
acid hydrazide (2) was synthesized according to the literature (26).
A mixture of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid ethyl ester (1,
10 mmol) and hydrazine hydrate (12 mmol) in 10 mL of methanol was
Data for 5b: pale yellow crystal; yield, 89%; mp 232-234 °C; IR (KBr)
υ (cm-1) 3088, 2931, 1606, 1579, 1501, 1438, 1249, 1013, 950, 767; 1H
NMR (DMSO-d6, 300 MHz) δ 8.29(1H, d, 3JHH = 7.8 Hz, benzene-H),
3
3
7.71 (1H, t, JHH = 7.5 Hz, benzene-H), 7.39 (1H, d, JHH = 8.4 Hz,

2632 J. Agric. Food Chem., Vol. 58, No. 5, 2010
Fan et al.
3
benzene-H), 7.27(1H, t, JHH = 7.8 Hz, benzene-H), 4.09 (3H, s,
956, 856; 1H NMR (DMSO-d6, 300 MHz) δ 8.47 (2H, d, 3JHH = 8.7 Hz,
3
benzene-H), 8.34 (2H, d, JHH = 8.7 Hz, benzene-H), 3.11 (3H, s,
Ar-OCH3), 3.11 (3H, s, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative
intensity) 330 (Mþ, 10), 302 (100), 169 (12), 126 (50), 83 (67), 45 (22),
39 (42). Anal. Calcd for C13H10N6OS2: C, 47.26; H, 3.05; N, 25.44. Found:
C, 47.18; H, 3.20; N, 25.58.
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 345 (Mþ, 2), 317
(100), 273 (4), 206 (3), 166 (19), 126 (42), 83 (38), 67 (23), 39 (29). Anal.
Calcd for C12H7N7O2S2: C, 41.73; H, 2.04; N, 28.39. Found: C, 41.61; H,
2.20; N, 28.18.
Data for 5c: pale yellow crystal; yield, 83%; mp 244-246 °C; IR (KBr)
υ (cm-1) 3088, 2920, 1616, 1574, 1501, 1448, 1254, 1034, 945, 851; 1H
NMR (DMSO-d6, 300 MHz) δ 8.02 (2H, d, 3JHH = 8.7 Hz, benzene-H),
7.21(2H, d, 3JHH = 8.7 Hz, benzene-H), 3.90 (3H, s, Ar-OCH3), 3.10
(3H, s, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 330 (Mþ,
10), 302 (100), 191 (13), 151 (69), 83 (38), 70 (14), 39 (25). Anal. Calcd for
C13H10N6OS2: C, 47.26; H, 3.05; N, 25.44. Found: C, 47.36; H, 3.14; N,
25.20.
Data for 5l: white fiber crystal; yield, 18%; mp > 280 °C; IR (KBr) υ
(cm-1) 3077, 2920, 1637, 1558, 1464, 1427, 1239, 1213, 1029, 956, 819, 783;
1H NMR (DMSO-d6, 300 MHz) δ 7.74-7.82 (m, 3H, benzene-H), 3.09
(s, 3H, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 368 (Mþ,
5), 340 (100), 296 (4), 229 (9), 189 (35), 169 (20), 126 (58), 83 (68), 39 (28).
Anal. Calcd for C12H6Cl2N6S2: C, 39.03; H, 1.64; N, 22.76. Found: C,
39.12; H, 1.83; N, 22.90.
Data for 5m: white flake crystal; yield, 96%; mp 225-227 °C; IR (KBr)
υ (cm-1) 3035, 2920, 1627, 1553, 1448, 1380, 1213, 1034, 961, 804, 751, 688;
1H NMR (DMSO-d6, 300 MHz) δ 7.84-7.87 (t, 3H, benzene-H),
7.64-7.79 (m, 2H, CHdCH), 7.47-7.48 (d, 2H, benzene-H), 3.09 (s,
3H, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 326 (Mþ, 8),
298 (100), 169 (10), 126 (29), 115 (40), 45 (14), 39 (16). Anal. Calcd for
C14H10N6S2: C, 51.52; H, 3.09; N, 25.75. Found: C, 51.51; H, 2.90; N, 25.55.
Data for 5n: white needle crystal; yield, 74%; mp 212-214 °C; IR
(KBr) υ (cm-1) 3025, 2983, 1553, 1522, 1454, 1380, 1275, 1207, 1129, 1029,
956, 804, 730; 1H NMR (DMSO-d6, 300 MHz) δ 5.32 (s, 2H, CH2), 3.07
(s, 3H, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 272
(Mþ, 7), 244 (100), 169 (15), 83 (66), 39 (45). Anal. Calcd for C7H5ClN6S2:
C, 30.83; H, 1.85; N, 30.81. Found: C, 30.70; H, 2.06; N, 30.73.
Data for 5o: white flake crystal; yield, 91%; mp 191-193 °C; IR (KBr)
υ (cm-1) 2920, 1553, 1511, 1469, 1443, 1380, 1213, 1019, 940, 819, 798, 767;
1H NMR (DMSO-d6, 300 MHz) δ 3.07 (s, 3H, thiadiazolyl-CH3); EI-MS
(70 eV, m/z, relative intensity) 340 (Mþ, 20), 314 (68), 277 (25), 169 (40),
126 (100), 83 (92), 70 (98), 39 (84). Anal. Calcd for C7H3Cl3N6S2: C, 24.61;
H, 0.89; N, 24.60. Found: C, 24.43; H, 1.10; N, 24.65.
Data for 5d: white needle crystal; yield, 86%; mp 225-227 °C; IR
(KBr) υ (cm-1) 3077, 2931, 1611, 1585, 1506, 1448, 1291, 1213, 1102, 956,
3
762; 1H NMR (DMSO-d6, 300 MHz) δ 8.26 (1H, t, JHH = 7.5 Hz,
3
benzene-H), 7.77-7.84 (1H, m, benzene-H), 7.62 (1H, d, JHH
=
3
8.4 Hz), 7.55 (1H, q, JHH = 7.5 Hz, benzene-H), 3.11 (3H, s,
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 318 (Mþ, 6),
290 (100), 246 (5), 139 (50), 83 (31), 39 (16). Anal. Calcd for C12H7FN6S2:
C, 45.27; H, 2.22; N, 26.40. Found: C, 45.50; H, 2.43; N, 26.21.
Data for 5e: white needle crystal; yield, 92%;mp 242-244 °C; IR(KBr)
υ (cm-1) 3088, 2931, 1590, 1558, 1517, 1443, 1275, 1213, 1008, 945, 851,
804; 1H NMR (DMSO-d6, 300 MHz) δ 7.92-7.96 (2H, m, benzene-H),
3
3
7.73(1H, q, JHH = 7.2 Hz, benzene-H), 7.60(1H, s, JHH = 7.5 Hz,
benzene-H), 3.11 (s, 3H, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative
intensity) 318 (Mþ, 4), 290 (100), 246 (5), 139 (62), 83 (38), 39 (25). Anal.
Calcd for C12H7FN6S2: C, 45.27; H, 2.22; N, 26.40. Found: C, 45.20; H,
2.35; N, 26.71.
Data for 5f: white needle crystal; yield, 96%; mp 243-245 °C; IR (KBr)
υ (cm-1) 3088, 2931, 1600, 1558, 1522, 1490, 1459, 1244, 1213, 1165, 956,
856, 814; 1H NMR (DMSO-d6, 300 MHz) δ 8.14(2H, t, 3JHH = 8.7 Hz,
3
benzene-H), 7.52 (2H, t, JHH = 8.7 Hz, benzene-H), 3.10 (3H, s,
Data for 5p: white needle crystal; yield, 83%; mp 176-177 °C; IR
(KBr) υ (cm-1) 2973, 2931, 1558, 1532, 1438, 1375, 1213, 1160, 1029, 945,
804; 1H NMR (DMSO-d6, 300 MHz) δ 3.09-3.14 (2H, m, CH2), 3.07
(3H, s, thiadiazolyl-CH3), 1.82 (2H, q, J = 7.5 Hz, CH2), 1.02 (3H, t, J =
7.2 Hz, CH3); EI-MS (70 eV, m/z, relative intensity) 266 (Mþ, 8), 238 (100),
194 (9), 169 (12), 126 (39), 83 (41), 39 (28), 27 (15). Anal. Calcd for
C9H10N6S2: C, 40.58; H, 3.78; N, 31.55. Found: C, 40.50; H, 3.98; N, 31.36.
Data for 5q: white needle crystal; yield, 83%; mp 199-201 °C; IR
(KBr) υ (cm-1) 2983, 2931, 1558, 1517, 1438, 1385, 1365, 1207, 1019, 940,
814; 1H NMR (DMSO-d6, 300 MHz) δ 3.07 (s, 3H, thiadiazolyl-CH3),
1.48 (s, 9H, C(CH3)3); EI-MS (70 eV, m/z, relative intensity) 280 (Mþ, 8),
252 (100), 208 (7), 169 (13), 141 (10), 126 (48), 83 (48), 57 (50), 41 (79),
27 (24). Anal. Calcd for C10H12N6S2: C, 42.84; H, 4.31; N, 29.97. Found:
C, 42.63; H, 4.23; N, 29.75.
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 318 (Mþ, 5),
290 (100), 139 (63), 126 (32), 39 (16). Anal. Calcd for C12H7FN6S2: C,
45.27; H, 2.22; N, 26.40. Found: C, 45.15; H, 2.10; N, 26.65.
Data for 5g: white fiber crystal; yield, 92%; mp 241-242 °C; IR (KBr)
υ (cm-1) 3077, 2931, 1606, 1558, 1454, 1323, 1223, 1186, 1129, 956, 772; 1H
NMR (DMSO-d6, 300 MHz) δ 7.94-8.11 (m, 4H, benzene-H), 3.10 (s,
3H, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 368 (Mþ,
2), 340 (100), 296 (3), 229 (4), 189 (30), 145 (12), 126 (33), 83 (38), 39 (16).
Anal. Calcd for C13H7F3N6S2: C, 42.39; H, 1.92; N, 22.81. Found: C,
42.30; H, 2.12; N, 22.75.
Data for 5h: white needle crystal; yield, 91%; mp 273-274 °C; IR (KBr)
υ (cm-1) 3067, 2931, 1616, 1558, 1517, 1459, 1422, 1333, 1186, 1076, 977,
3
819; 1H NMR (DMSO-d6, 300 MHz) δ 8.38 (1H, d, JHH = 9.0 Hz,
3
Data for 5r: gray needle crystal; yield, 91%; mp 236-238 °C; IR (KBr)
υ (cm-1) 3109, 2941, 1590, 1506, 1438, 1396, 1213, 1040, 987, 825, 767; 1H
NMR (DMSO-d6, 300 MHz) δ 6.91 (1H, s, furyl-H), 7.65 (1H, s,
furyl-H), 8.19 (1H, s, furyl-H), 3.09 (3H, s, thiadiazolyl-CH3); EI-
MS (70 eV, m/z, relative intensity) 290 (Mþ, 9), 262 (100), 169 (11), 111
(58), 83 (34), 39 (39). Anal. Calcd for C10H6N6OS2: C, 41.37; H, 2.08; N,
28.95. Found: C, 41.15; H, 2.12; N, 28.79.
benzene-H), 8.31(1H, s, benzene-H), 8.11 (1H, d, JHH = 7.8 Hz,
3
benzene-H), 7.92 (1H, t, JHH = 7.8 Hz, benzene-H), 3.10 (3H, s,
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 368 (Mþ, 2),
340 (100), 296 (4), 229 (6), 189 (49), 169 (11), 126 (30), 83 (29), 39 (11). Anal.
Calcd for C13H7F3N6S2: C, 42.39; H, 1.92; N, 22.81. Found: C, 42.43; H,
2.16; N, 22.90.
Data for 5i: gray needle crystal; yield, 92%; mp 287-289 °C; IR (KBr)
υ (cm-1) 3077, 2941, 1616, 1553, 1501, 1454, 1323, 1171, 1123, 1066, 950,
Data for 5s: pale yellow needle crystal; yield, 90%; mp 239-241 °C; IR
(KBr) υ (cm-1) 3088, 3046, 2931, 1600, 1558, 1464, 1412, 1213, 971, 987, 950,
3
867; 1H NMR (DMSO-d6, 300 MHz) δ 8.29 (2H, d, JHH = 8.4 Hz,
3
846; 1H NMR (DMSO-d6, 300 MHz) δ 8.90 (2H, d, JHH = 4.8 Hz,
3
benzene-H), 8.04 (2H, d, JHH = 8.4 Hz, benzene-H), 3.11 (3H, s,
3
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 368 (Mþ, 2),
340 (100), 296 (4), 229 (6), 189 (40), 145 (9), 126 (22), 83 (18), 39 (5). Anal.
Calcd for C13H7F3N6S2: C, 42.39; H, 1.92; N, 22.81. Found: C, 42.50; H,
1.98; N, 22.76.
pyridyl-H), 8.03 (2H, d, JHH = 4.8 Hz, pyridyl-H), 3.11 (3H, s,
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 301 (Mþ, 5), 273
(100), 229 (5), 169 (8), 126 (28), 122 (31), 67 (15), 39 (12). Anal. Calcd for
C11H7N7S2: C, 43.84; H, 2.34; N, 32.54. Found: C, 43.80; H, 2.38; N, 32.67.
Data for 5t: white needle crystal; yield, 86%; mp 232-234 °C; IR (KBr)
υ (cm-1) 2983, 2931, 1564, 1532, 1454, 1412, 1380, 1291, 1218, 1186, 1024,
Data for 5j: golden flake crystal; yield, 84%; mp 251-253 °C; IR (KBr)
υ (cm-1) 3074, 2929, 1613, 1534, 1512, 1446, 1346, 1214, 1123, 1008, 950,
820; 1H NMR (DMSO-d6, 300 MHz) δ 8.48-8.72 (3H, m, benzene-H),
7.96 (1H, t, 3JHH = 7.8 Hz, benzene-H), 3.11(3H, s, thiadiazolyl-CH3);
EI-MS (70 eV, m/z, relative intensity) 345 (Mþ, 2), 317 (100), 273 (4),
206 (3), 166 (21), 126 (39), 83 (38), 70 (22), 39 (26). Anal. Calcd
for C12H7N7O2S2: C, 41.73; H, 2.04; N, 28.39. Found: C, 41.90; H, 2.11;
N, 28.56.
956, 924, 804; 1H NMR (DMSO-d6, 300 MHz)
δ 6.85 (1H, s,
pyrazolyl-CH), 3.88 (3H, s, N-CH3), 3.09 (3H, s, thiadiazolyl-CH3),
2.96-2.77 (2H, q, 3JHH = 7.5 Hz, CH2), 1.27 (3H, t, 3JHH = 7.5 Hz, CH3);
EI-MS (70 eV, m/z, relative intensity) 332 (Mþ, 10), 304 (100), 246 (6), 153
(48), 83 (45), 39 (22). Anal. Calcd for C12H12N8S2: C, 43.36; H, 3.64; N,
33.71. Found: C, 43.52; H, 3.58; N, 33.60.
Data for 5k: golden flake crystal; yield, 93%; mp 285-287 °C; IR
(KBr) υ (cm-1) 3088, 2941, 1606, 1553, 1517, 1454, 1349, 1218, 1108, 1008,
Data for 5u: green needle crystal; yield, 96%; mp 211-213 °C; IR
(KBr) υ (cm-1) 2920, 1558, 1443, 1375, 1218, 1034, 950, 908, 825, 762;

Article
J. Agric. Food Chem., Vol. 58, No. 5, 2010 2633
Table 1. Selected Bond Lengths and Bond Angles for Compound 5c
˚
length (A)
˚
length (A)
˚
length (A)
bond
bond
bond
S(1)-N(2)
S(2)-C(5)
N(3)-C(4)
N(5)-C(5)
N(6)-C(6)
C(2)-C(3)
1.6694(14)
1.7359(15)
1.3239(19)
1.3569(18)
1.3065(18)
1.377(2)
S(1)-C(3)
S(2)-C(6)
N(3)-N(4)
N(5)-C(4)
O(1)-C(10)
C(3)-C(4)
1.7125(16)
1.7756(15)
1.4013(16)
1.3635(18)
1.3611(18)
1.4520(19)
N(1)-N(2)
N(1)-C(2)
N(4)-C(5)
N(5)-N(6)
O(1)-C(13)
C(7)-C(8)
1.2930(2)
1.3680(2)
1.3189(19)
1.3641(17)
1.4261(19)
1.3900(2)
angle
deg
angle
deg
angle
deg
N(2)-S(1)-C(3)
N(2)-N(1)-C(2)
C(5)-N(4)-N(3)
C(2)-C(3)-S(1)
N(5)-C(4)-C(3)
C(4)-N(5)-N(6)
N(5)-C(5)-S(2)
C(5)-S(2)-C(6)
N(1)-N(2)-S(1)
C(5)-N(5)-C(4)
C(4)-C(3)-S(1)
N(4)-C(5)-N(5)
C(6)-N(6)-N(5)
92.52(7)
114.50(13)
105.62(11)
107.91(11)
121.93(13)
133.46(12)
108.20(11)
88.04(7)
N(6)-C(6)-C(7)
C(10)-O(1)-C(13)
C(4)-N(3)-N(4)
C(5)-N(5)-N(6)
N(3)-C(4)-C(3)
N(4)-C(5)-S(2)
N(3)-C(4)-N(5)
N(6)-C(6)-S(2)
C(2)-N(1)-N(2)-S(1)
C(4)-N(3)-N(4)-C(5)
C(4)-N(5)-N(6)-C(6)
N(2)-N(1)-C(2)-C(3)
N(1)-C(2)-C(3)-C(4)
120.48(13)
117.21(12)
108.57(12)
120.15(12)
129.53(13)
140.90(11)
108.54(12)
116.07(11)
-0.48(17)
-0.05(15)
178.89(14)
-0.22(19)
-178.04(14)
N(1)-C(2)-C(3)-S(1)
N(2)-S(1)-C(3)-C(4)
N(4)-N(3)-C(4)-N(5)
N(6)-N(5)-C(4)-N(3)
N(6)-N(5)-C(4)-C(3)
S(1)-C(3)-C(4)-N(5)
N(3)-N(4)-C(5)-N(5)
N(3)-N(4)-C(5)-S(2)
N(6)-N(5)-C(5)-N(4)
N(6)-N(5)-C(5)-N(4)
C(6)-S(2)-C(5)-N(4)
C(7)-C(8)-C(9)-C(10)
C(8)-C(9)-C(10)-O(1)
0.77(16)
178.04(12)
0.23(15)
-179.07(14)
1.30(2)
-0.21(19)
-0.15(15)
179.06(14)
179.24(12)
179.24(12)
-179.14(18)
0
112.07(11)
106.38(12)
122.67(11)
110.89(12)
107.54(12)
-179.25(13)
1H NMR (DMSO-d6, 300 MHz) δ 3.03 (s, 3H, thiadiazolyl-CH3), 3.10
(s, 3H, thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 322
(Mþ, 6), 294 (99), 266 (40), 141 (14), 126 (84), 83 (100), 39 (79). Anal. Calcd
for C9H6N8S3: C, 33.53; H, 1.88; N, 34.76. Found: C, 33.43; H, 2.03; N,
34.85.
arachidicola (CA), Cercospora beticola (CB), Colletotrichum lagenarium
(CL), Fusarium oxysporum (FO), Gibberella zeae (GZ), Macrophoma
kuwatsukai (MK), Phytophthora infestans (Mont) de Bary (PI), Physalos-
pora piricola (PP), Pellicularia sasakii (Shirai) (PS), Puccinia triticina Eriks
(PT), and Rhizoctonia solani Kuhn (RS). Precision toxicity studies were
conducted according to the above methods by determination of growth
inhibition of specific fungi using the same compound by five to seven
different concentrations; the median effective concentration (EC50) was
calculated by the linear regression of logarithm of the concentration with
probability of the corresponding growth inhibition by Excel (29).
Systemic Acquired Resistance Screening. Using tobacco against the
tobacco mosaic virus (TMV) system described in ref 25, the induction
activity was evaluated using the antivirus inhibition ratio, which was
calculated by the average number of the viral inflammations on the
inoculated leaves with the corresponding control. TDL was chosen as
positive control; all compounds tested was conducted at 100 μg/mL of
concentration.
Data for 5v: gray needle crystal; yield, 62%; mp 252-254 °C; IR (KBr)
υ (cm-1) 2931, 1553, 1443, 1375, 1265, 1213, 1024, 950, 893, 830; 1H NMR
(DMSO-d6, 300 MHz) δ 3.10 (s, 3H, thiadiazolyl-CH3), 3.13 (s, 3H,
thiadiazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 322 (Mþ, 10),
294 (100), 234 (18), 141 (7), 126 (62), 39 (45). Anal. Calcd for C9H6N8S3: C,
33.53; H, 1.88; N, 34.76. Found: C, 33.51; H, 2.00; N, 34.90.
Data for 5w: pale yellow fiber crystal; yield, 73%; mp 233-234 °C; IR
(KBr) υ (cm-1) 3067, 2920, 1590, 1564, 1454, 1375, 1291, 1213, 1029, 945,
893, 777, 694; 1H NMR (DMSO-d6, 300 MHz) δ 7.57-7.72 (m, 5H,
benzene-H), 3.06 (s, 3H, thiadiazolyl-CH3), 2.86 (s, 3H, iso-
xazolyl-CH3); EI-MS (70 eV, m/z, relative intensity) 381 (Mþ, 3), 353
(100), 216 (5), 142 (21), 77 (41), 43 (78). Anal. Calcd for C16H11N7OS2: C,
50.38; H, 2.91; N, 25.70. Found: C, 50.42; H, 3.02; N, 25.55.
Data for 5x: pale yellow fiber crystal; yield, 87%; mp 250-251 °C; IR
(KBr) υ (cm-1) 3098, 2931, 1532, 1490, 1454, 1375, 1296, 1207, 1066, 961,
798, 762; 1H NMR (DMSO-d6, 300 MHz) δ 7.40-7.70 (m, 3H,
benzene-H), 5.78 (s, 2H, CH2), 3.07 (s, 3H, thiadiazolyl-CH3); EI-MS
(70 eV, m/z, relative intensity) 398 (Mþ, 1), 370 (52), 314 (10), 209 (86), 133
(30), 84 (100), 57 (58). Anal. Calcd for C13H8Cl2N6OS2: C, 39.11; H, 2.02;
N, 21.05. Found: C, 39.06; H, 2.18; N, 21.15.
RESULTS AND DISCUSSION
Preparation of the Novel 6-Substituted-3-(4-Methyl-1,2,3-
thiadiazolyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizole Derivatives. The
reaction sequence employed for the synthesis of the title compounds
is shown in Scheme 1. The starting material 4-methyl-1,2,3-thiadia-
zole-5-carboxylic acid ethyl ester was prepared according to the
literature (25). 4-Methyl-1,2,3-thiadiazole-5-carboxylic acid hydra-
zide 2, which was obtained by reaction of 4-methyl-1,2,3-thiadia-
zole-5-carboxylic acid ethyl ester with hydrazine hydrate (26),
reacted with carbon disulfide in methanolic potassium hydroxide
to give dithiocarbazinate 3 in good yield and was directly used for
the next reaction without further purification. The key intermediate
4 was synthesized by refluxing dithiocarbazinate 3 with hydrazine
hydrate without the step of iodomethylation as described in the
literature (27). Condensation of 4 with various substituted car-
boxylic acids in the presence of phosphorus oxychloride under
refluxing gave the title compounds 6-substituted-3-(4-methyl-1,2,3-
thiadiazolyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizoles 5 in good
yield (28).
Crystal Structure Determination for Compound (5c). The crystal
of compound 5c was cultured from DMSO. X-ray intensity data were
recorded on a Bruker SMART 1000 CCD diffraction meter using graphite
˚
monochromated Mo KR radiation (λ = 0.71073 A). A total of 9505
reflections were measured, of which 3274 were unique (Rint = 0.0384) in
the range of 2.14° e θ e 27.88° (h, -8 to 14; k, -6 to 6; l, -31 to 31), and
2802 observed reflections with I > 2σ(I) were used in the refinement on F2.
The structure was solved by direct methods with the SHELXS-97
program. All of the non-H atoms were refined anisotropically by full-
matrix least-squares to give the final R = 0.0329 and wR = 0.0866 (w =
1/[σ2(F02) þ (0.0490P)2 þ 0.30P]), where P = (F0 þ 2Fc )/3) with (Δ/
σ)max = 0.001 and S = 1.082 by using the SHELXL program. The
hydrogen atoms were located from a difference Fourier map and refined
isotropically.
2
2
Biological Screening. Biological activities of the target compounds
were evaluated systematically including fungicide and systemic acquired
resistance according to the standard operation practice (SOP) as follows.
Fungicide Screening. Preliminary screening was conducted by
fungus growth inhibition method according to ref 25. Fungi used in this
studies included Alternaria solani(AS), Botrytis cinerea (BC), Cercospora
The structures of all newly synthesized compounds were
characterized by elemental analysis, IR, 1H NMR, and MS
studies. Intermediate 4 existed both in thione and in thiol
tautomeric forms (1) and showed two characteristic broad signals
at δ 6.08 and 14.34. Due to the reaction of NH2 and SH with acid,

2634 J. Agric. Food Chem., Vol. 58, No. 5, 2010
Fan et al.
1
their H NMR signals disappeared in the title products 5. As a
single-crystal diffraction of 5c were further validated the structure
of the title compounds because there existed many N and limited
C and H in this molecule, which gave limited information in
1H NMR chromatography. Bond lengths and angles within the
heterocyclic system (Table 1) agreed well with the standard values
for compound 5c. The bond lengths indicated some degree of
delocalization around the ring system, with the three CdN bonds
result of the overall inductive effect and magnetic anisotropic
effect of the triazolothiadiazole ring, the chemical shift of the CH3
group in the thiadiazole moiety in the target compounds appears
downfield at δ 2.98-3.15. The EI-MS spectra of 5 showed each of
their molecular ion peaks Mþ at a relative intensity of 1-20%. All
of the fragmentation ions were consistent with their structures
and could be clearly assigned. In addition, the results of X-ray
˚
averaging 1.3148 (3) A and the N;N bonds ranging from 1.3641
˚
(17) to 1.4013 (16) A. Compound 5c (Figure 1) consists of a fused
triazolothiadiazole system, one 1,2,3-thiadiazole ring, and one
phenyl ring. The four rings are almost coplanar, with average
deviations from planarity of 0.0011(2), 0.0008(2), 0.0041(3), and
˚
0.0018(3) A for the triazole ring, 1,3,4-thiadiazole ring, 1,2,3-
thiadiazole ring, and phenyl ring, respectively. As expected, the
1,2,4-triazole and 1,3,4-thiadiazole rings are planar; the dihedral
angle between rings is 0.7°, which can be attributed to a wide
range of electron delocalization. The 1,2,4-triazole ring is almost
coplanar with the 1,2,3-thiadiazole ring with a dihedral angle of
1.7(3)°, whereas the phenyl ring is rotated by 5.6(2)° as compared
with the 1,3,4-thiadiazole ring. In the crystal lattice, there exist
two intermolecular hydrogen bonds, N2 H-C12 and N3
3 3 3
3 3 3
Figure 1. X-ray structure of compound 5c.
H-C13, and one weak intermolecular interaction (S S) as
3 3 3
shown in Figure 2. In addition, the weak pπ-pπ intermolecular
interaction was observed, too. The planes of the 1,2,3-triazole
ring, phenyl ring, and fused 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole
ring system are parallel to each other for each molecule. Another
compound, 5u, was also synthesized, and its crystal structure was
cultured and determined; the results also validated the structure
of this kind of derivative (30).
Biological Activity. Fungicide activities against the representa-
tive typical fungi often occurring in the Chinese agro-ecosystem
such as AS, BC, CA, CB, CL, FO, GZ, PI, PP, PS, PT, and RS
were detected at 50 μg/mL. The results indicated that some
compounds had good fungicide activity (Table 2). All compounds
have good growth inhibition to BC, compounds 5b, 5d, and 5g
inhibited >50% of the growth to PS, PS, and FO, respectively;
Figure 2. Packing diagram in a unit cell of compound 5c.
Table 2. Fungicide Activity of the Title Compounds (Percent)a
compd
AS
BC
CA
CB
CL
FO
GZ
PI
PP
PS
PT
nd
RS
5a
5b
5c
5d
5e
5f
30.0
23.3
0
50.0
nd
25.0
18.2
7.7
30.0
14.3
0
27.3
0
17.2
19.4
44.4
19.4
10.0
9.3
18.2
nd
11.1
17.3
4.8
24.4
45.2
7.7
32.84
60.8
46.4
58.8
32.8
11.3
35.7
35.2
30.4
25.0
32.4
42.3
33.3
38.4
84.8
77.8
56.7
45.1
44.6
30.4
45.3
44.4
25.4
33.3
nd
31.6
10.0
21.1
nd
nd
nd
18.2
11.8
0
nd
11.1
nd
40.0
37.1
26.3
4.8
nd
18.2
23.5
33.1
7.7
23.8
27.3
7.1
nd
20.0
0
24.2
54.1
18.6
15.4
25.6
17.9
12.8
34.9
37.2
40.5
33.3
83.9
40.5
17.7
29.0
7.7
75.0
53.3
nd
40.5
14.3
nd
nd
10.3
45.5
13.8
18.2
0
15.6
0
nd
nd
5g
5h
5i
0
86.0
18.6
44.4
47.2
20.9
13.9
9.1
0
5.6
nd
23.7
9.5
68.9
nd
23.1
15.4
7.7
35.7
0
4.8
17.8
4.8
nd
nd
70.0
10.0
nd
11.1
11.1
nd
5j
9.5
nd
0
nd
54.8
22.2
20.0
18.2
11.4
70.7
75.8
14.7
14.7
0
5k
5l
26.7
23.7
31.3
23.8
66.7
34.4
16.7
43.3
9.5
60.0
64.4
81.8
65.2
nd
30.8
23.1
27.6
34.8
63.6
62.1
36.4
36.4
23.1
7.7
14.3
28.6
13.3
21.4
71.4
33.3
23.8
42.9
0
13.8
20.7
26.9
4.3
11.9
14.3
17.5
33.3
nd
nd
nd
5m
5n
5o
5p
5q
5r
nd
nd
25.0
75.0
93.0
13.9
22.2
44.4
47.2
18.6
9.1
nd
nd
64.7
50.0
78.9
nd
83.3
nd
84.9
nd
75.0
nd
5.88
0
26.3
21.0
10.0
10.0
nd
nd
nd
nd
nd
5s
5t
nd
27.3
0
nd
5.7
19.4
nd
9.5
nd
0
nd
4.8
12.8
20.5
23.8
8.9
5u
5v
5w
5x
30.3
31.3
33.3
31.3
67.5
81.8
46.2
nd
48.5
34.5
30.0
31.0
24.9
20.0
10.0
20.0
30.8
19.2
13.6
19.2
21.5
30.0
27.3
12.5
37.6
18.2
7.4
nd
nd
13.8
3.0
nd
nd
12.1
23.8
nd
nd
a AS, Alternaria solani; BC, Botrytis cinerea; CA, Cercospora arachidicola; CB, Cercospora beticola; CL, Colletotrichum lagenarium; FO, Fusarium oxysporum; GZ, Gibberella
zeae; MK, Macrophoma kuwatsukai; PI, Phytophthora infestans (Mont) de Bary; PP, Physalospora piricola; PS, Pellicularia sasakii (Shirai); PT, Puccinia triticina Eriks; RS,
Rhizoctonia solani Kuhn; nd, not detected.

Article
J. Agric. Food Chem., Vol. 58, No. 5, 2010 2635
Table 3. EC50 Determination of Compound 5o against Six Fungi
fungus
regression equation
R2
EC50 (μg/mL)
EC50 (μmol/L)
Alternaria solani
Fusarium oxysporum f. cucumerinum
Macrophoma kuwatsukai
y = 0.8577x þ 3.9950
y = 0.7959x þ 4.1643
y = 0.9710x þ 4.2185
y = 0.8570x þ 4.0613
y = 1.1611x þ 4.5416
y = 1.2018x þ 4.2649
0.9879
0.9154
0.9549
0.9509
0.9148
0.9262
14.6
11.2
6.4
42.49
32.59
18.62
36.38
7.28
Phytophthora infestans (Mont.) de Bary
Pellicularia sasakii (Shirai)
Rhizoctonia solani
12.5
2.5
4.1
11.93
Table 4. Antivirus Activities of the Title Compounds (Percent)a
induction activity. All compounds synthesized had certain degree
of phototoxicity to tobacco during the course of screening for
induction activity; the leavescurved, rotted, or dried severely after
treatment with these compounds. All of the biological screen-
ings indicated that 6-substituted-3-(4-methyl-1,2,3-thiadiazolyl)-
[1,2,4]triazolo[3,4-b][1,3,4]thiadizoles exhibited various biologi-
cal activities: they were the fungicide lead compounds.
compd
500 μg/mL
100 μg/mL
50 μg/mL
5a
nd
nd
40
5b
5c
nd
nd
0
nd
nd
17.86
nd
5d
5e
53.57
30.71
nd
9.50
24.24
nd
nd
5f
0
5g
5h
5i
nd
nd
25
ABBREVIATIONS USED
37.50
nd
30.00
nd
nd
AS, Alternaria solani; BC, Botrytis cinerea; BTH, acibenzolar-
S-methyl; CA, Cercospora arachidicola; CB, Cercospora beticola;
CL, Colletotrichum lagenarium; DMSO-d6, deutero-, dimethyl
sulfoxide; EC50, median effective concentration; EI/MS, electro-
ionization mass spectrometry; FO, Fusarium oxysporum; GZ,
10.15
nd
5j
44.44
52.94
nd
44.44
16.67
nd
5k
nd
5l
12.5
nd
5m
5n
5o
5p
5q
5r
27.78
nd
16.67
nd
1
29.17
nd
Gibberella zeae; H NMR, proton nuclear magnetic resonance;
27.78
nd
33.33
nd
HRMS, high-resolution mass spectrometry; IR, infrared spec-
troscopy; MK, Macrophoma kuwatsukai; nd, not detected; PDA,
potato dextrose agar; PI, Phytophthora infestans (Mont) de Bary;
PP, Physalospora piricola; PS, Pellicularia sasakii (Shirai); PT,
Puccinia triticina Eriks; RS, Rhizoctonia solani Kuhn; SOP,
standard operation practice; TDL, Tiadinil; TMS, tetramethylsi-
lane; TMV, tobacco mosaic virus.
0
nd
nd
7.89
nd
23.53
nd
20
5s
nd
27.03
34.78
11.76
nd
5t
nd
nd
5u
5v
nd
nd
30.77
nd
26.67
nd
5w
5x
14.63
0
nd
nd
ACKNOWLEDGMENT
ribavirin
tiadinil
37.93
nd
21.62
36.59
16.7
nd
We are grateful to Professor Bakulev Vasiliy Alekseevich of the
TOSLab, Urals State Technical University, for his kind sugges-
tion. We are indebted to Zhiyin Fan for his hard work in
biological screening.
a nd, not detected.
compound 5o was a broad-spectrum of fungicide against all of the
fungi tested withgrowthinhibition from60to85%; compound5p
also exhibited broad spectrum of fungicidal activity against PS,
PI, GZ, FO, and CA with growth inhibition of 77.8, 75.8, 75.0,
93.0, and 62.1%, respectively. Precision toxicity of compound 5o
was studied further, and EC50 values were detected from 7.28
μmol/L against Pellicularia sasakii (Shirai) to 42.49 μmol/L
against Alternaria solani to six fungi tested as listed in Table 3.
This indicated that compound 5o was a fungicide lead and
deserved further modification. Aliphatic or halogen-substituted
aliphatic derivatives such as chlorinated aliphatic derivatives had
better fungicide activity than aromatic derivatives; diverse deri-
vatives need to be synthesized and screened for further studies.
The antivirus activity of the novel compounds synthesized was
evaluated systemically. The results in Table 4 indicated that
ribavirin exhibited certain degree of anti-TMV activity at 500
μg/mL, but had almost no activity at 50 μg/mL, and compounds
5d and 5k had good anti-TMV activity at 500 μg/mL; however,
they had almost no antivirus activity when the concentration was
lowered to 100 μg/mL. Compounds 5a, 5n, and 5t had good anti-
TMV activity with inhibition of about 30% even at 50 μg/mL. To
get clear structure-activity relationship results of antivirus study,
more derivatives of heterocyclic acid need to be synthesized and
tested. Induction screening of systemic acquired resistance for
tobacco against TMV at 100 μg/mL indicated that ribavirin
exhibited no induction activity, whereas TDL had 48.92%
Note Added after ASAP Publication
There was an error in the page numbers of reference 30 in the
version of this paper published ASAP December 16, 2009; the
corrected version published ASAP February 3, 2010.
Supporting Information Available: Crystal data of com-
pound 5c: r80811a.cif. This information is available free of charge
via the Internet at http://pubs.acs.org.
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Received for review June 21, 2009. Revised manuscript received
October 2, 2009. Accepted November 19, 2009. This study was funded
in part by grants from the National Natural Science Foundation of
China (No. 20872071 and 20672062), the National Key Project for
Basic Research (No. 2003CB114402 and 2010CB126105), the Tianjin
Natural Science Foundation (No. 07JCYBJC01200), the International
Collaboration Program of the National Natural Science Foundation of
China (No. 20911120069), and the Key Laboratory of Pesticide
Chemistry and Application, Ministry of Agriculture (MOA), Beijing
100193, People’s Republic of China (No. MOAPCA200903).
€
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