English

• 1.   Introduction

  3-Carene, a naturally occurring chiral monoterpene, is mainly found in some essential oils and some turpentine oils of special pine trees.^{[1, 2]} It is one of the rare compounds in nature containing a three-membered gem- dimethylcyclopropane ring. As a renewable forest biomass resource, 3-carene exhibited various biological activities, such as anti-inflammatory, ^[3] antioxidant, ^{[4, 5]} antimicrobial^{[4, 5]} and antitumor properties.^[6] Various cyclopropane- containing bioactive derivatives can be synthesized through modification of the molecular structure of 3- carene.^[7]

  Cyclopropane derivatives, which play important roles in the fields of pesticides and medicine, have recently received considerable attention. Pyrethroids, as an important class of cyclopropane derivatives, have been used for decades because of their broad spectrum, low toxicity and highly bioactive insecticidal properties.^[8] Additionally, some compounds containing cyclopropyl skeleton also displayed widespread biological activities, such as acetylcholinesterase inhibitory, ^[9] anticancer, ^[10~13] antimicrobial, ^[14] antifungal, ^[15] anti-inflammatory^[16] and herbicidal.^[17] On the other hand, 1, 2, 4-triazole derivatives are widely applied in medicine and agriculture because of their various biological activities, including antifungal, ^[18~20] antibacterial, ^{[21, 22]} antimicrobial, ^[23] antiviral, ^[24] antitumor, ^[25~27] antioxidant^[28] and herbicidal activities.^[29~31] In continuation of our interest in the bioactive properties of natural product-based compounds, ^{[18, 32~36]} a series of novel 4-methyl- 1, 2, 4-triazole-thioethers containing gem-dimethylcyclo- propane ring were designed and synthesized by integrating bioactive 1, 2, 4-triazole and thioether moieties into the skeleton of gem-dimethylcyclopropane converted from 3-carene (racemate). In this work, all title compounds were racemates, and their structural characterization, antifungal and herbicidal evaluation were carried out as well.

  As a valuable predictive tool in the design of pharmaceuticals and agrochemicals, 3D-QSAR certainly saved time and reduced cost by facilitating the selection of the most promising candidates.^[37] And a validated 3D-QSAR model was beneficial to understand the structure-activity relationships of molecules and provided the researcher an insight at the molecular level about the lead molecules for further development.^[38] Therefore, in order to improve the efficiency of discovering new potential antifungal agents, the 3D-QSAR analysis of the antifungal activity against P. piricola of the target compounds was carried out. The effective 3D-QSAR model provided a theoretical basis for the subsequent optimization of the series of compounds and the discovery of new potential antifungal agents with high activity.

  2.   Results and discussion

  2.1   Synthesis and characterization

  As illustrated in Scheme 1, 2-(2, 2-dimethyl-3-(2-oxo-propyl)cyclopropyl) acetic acid (2) was prepared according to the reported method^[39] from raw material 3-carene. And intermediate 2-(2, 2-dimethyl-3-propylcyclopropyl)acetic acid (3) was prepared by reduction of the carbonyl group in compound 2 through Wolff-Kishner-Huang reduction method. Denitrification was critical throughout the reduction process, and the reaction temperature needed to be maintained at over 180 ℃ for 8 h. The ¹H NMR and ¹³C NMR signals of compound 3 were assigned by HMBC and HSQC spectra. The intermediate 5-((2, 2-dimethyl-3-propyl cyclopropyl)methyl)-4-methyl-2, 4-dihydro-3H-1, 2, 4-tria-zole-3-thione (5) was prepared by N-acylation of 4-methyl- thiosemicarbazide with 2-(2, 2-dimethyl-3-propylcyclo- propyl)acetyl chloride (4) followed by self-cyclization reaction. Then, twenty target compounds 6a~6t were synthesized by nucleophilic substitution reaction of the intermediate 5 with a series of alkyl halides.

  Scheme 1

  

  Scheme 1.  Synthesis of 4-methyl-1, 2, 4-triazole-thioethers 6a~6t containing gem-dimethylcyclopropane ring

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  The target compounds 4-methyl-1, 2, 4-triazole-thioethers were characterized by FTIR, ¹H NMR, ¹³C NMR, ESI-MS, elemental analysis and UV-Vis. In the IR spectra, the strong absorption band at 1465~1488 cm^－1 was attributed to the vibration of C＝N in 1, 2, 4-triazole moiety. The absorption bands in the region of 680~700 cm^－1 were due to the vibrations of C—S—C. In the ¹H NMR spectra, the protons of benzene ring showed signals at δ 6.76~7.41. The protons of gem-dimethylcyclopropane ring scaffold showed signals in the range of δ 0.59~2.73. The characteristic signals at δ 3.06~3.52 were assigned to the methyl protons of 1, 2, 4-triazole moiety. The protons on the saturated carbon bonded to the S atom displayed the signals at δ 3.11~4.50. The ¹³C NMR spectra of all the target compounds showed peaks of the gem-dimethylcyclopropane ring scaffold carbons were in the region of δ 14.06~28.99. For the 1, 2, 4-triazole moiety, the signals at δ 156.26~156.99 and 148.45~150.41 were assigned to the unsaturated carbons, and at δ 28.94~30.12 to methyl. The saturated carbon bonded to the S atom displayed the signals at δ 30.01~39.81. Their molecular weights were confirmed by the ESI-MS.

  2.2   Antifungal activity

  The antifungal activities of all target compounds were tested by an in vitro method against fusarium wilt on cucumber (Fusarium oxysporum f. sp. cucumerinum), speckle on peanut (Cercosporaarachidicola), apple root spot (Physalosporapiricola), tomato early blight (Alternaria solani), wheat scab (Gibberellazeae), rice sheath blight (Rhizoctoniasolani), corn southern leaf blight (Bipolaris maydis), and watermelon anthracnose (Colleterichumorbicalare) at 50 μg/mL. The results were listed in Table 1.

  Table 1

  

  Table 1.  Antifungal activities of the target compounds 6a~6t at 50 μg/mL^a

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  Compd.	Inhibition rate/%
  	F. oxysporum f. sp. Cucumerinum	C. arachidicola	P. piricola	A. solani	G. zeae	R. solani	B. myadis	C. orbicalare
  Chlorothalonil	100	73.3	75.0	73.9	73.1	96.1	90.4	91.3
  5	24.0	43.8	55.0	42.1	30.0	51.9	33.3	42.9
  6a	37.1	39.1	95.5	42.9	41.4	77.5	47.2	55.6
  6b	45.7	39.1	52.3	50.0	44.8	70.4	52.8	47.2
  6c	28.6	43.5	79.5	46.4	37.9	57.7	41.7	50.0
  6d	37.1	30.4	75.0	42.9	51.7	70.4	52.8	50.0
  6e	37.1	65.2	90.9	57.1	44.8	74.6	61.1	52.8
  6f	42.9	26.1	77.3	42.9	58.6	71.8	47.2	55.6
  6g	25.7	52.2	59.1	42.9	44.8	70.4	30.6	30.6
  6h	31.4	30.4	75.0	42.9	44.8	70.4	55.6	38.9
  6i	40.0	26.1	68.2	35.7	44.8	69.0	44.4	55.6
  6j	25.7	26.1	77.3	35.7	41.4	69.0	27.8	30.6
  6k	48.6	52.2	75.0	50.0	62.1	66.2	50.0	58.3
  6l	25.7	21.7	84.1	39.3	37.9	70.4	52.8	50.0
  6m	40.0	65.2	40.9	50.0	37.9	62.0	52.8	50.0
  6n	62.9	69.6	75.0	60.7	44.8	70.4	66.7	61.1
  6o	34.3	65.2	56.8	57.1	55.2	66.2	36.1	41.7
  6p	37.1	21.7	52.3	42.9	58.6	69.0	36.1	52.8
  6q	40.0	73.9	86.4	60.7	44.8	54.9	47.2	41.7
  6r	25.7	47.8	52.3	50.0	51.7	38.0	33.3	41.7
  6s	22.9	30.4	75.0	35.7	24.1	47.9	30.6	33.3
  6t	42.9	21.7	68.2	35.7	37.9	70.4	27.8	44.4
  a Chlorothalonil, a current commercial fungicide, was used as a positive control. Values are the average of three replicates.

  It was found that, compounds 6a~6t exhibited significantly different antifungal activity against the eight tested fungi at a concentration of 50 μg/mL. Compared with the intermediate 5, the activities of most target compounds against the eight fungi were enhanced after etherification, especially for the inhibition against P. piricola and R. solani. On the whole, most of the target compounds exhibited the best antifungal activity against P. piricola, in which compounds 6a (R＝Ph), 6e (R＝o-ClC₆H₄), 6q (R＝α-pyridyl), 6l (R＝p-vinyl-C₆H₄), 6c (R＝m-Me- C₆H₄), 6f (R＝m-ClC₆H₄) and 6j (R＝p-MeSC₆H₄) had inhibition rates of 95.5%, 90.9%, 86.4%, 84.1%, 79.5%, 77.3% and 77.3%, respectively, showing better antifungal activity than that of the commercial fungicide of chlorothalonil with the inhibition rate of 75.0%. Also, ten target compounds showed moderate activity in the region of 70.4%~77.5% inhibition rates against R. solani. In addition, compound 6q (R＝α-pyridyl) displayed better inhibitory activity of 73.9% against C. arachidicola than that of the positive control with inhibition rate of 73.3%. Compounds 6a (R＝Ph) and 6e (R＝o-ClC₆H₄) were lead compound worthy of further study.

  2.3   Herbicidal activity

  The herbicidal activities of the target compounds 6a~6t were evaluated by the rape petri dish method and the barnyard grass beaker method against the root-growth of rape (Brassica campestris) and the seedling-growth of barnyard grass (Echinochloa crusgalli) at 10 and 100 μg/mL, respectively. The tested results were listed in Table 2.

  Table 2

  

  Table 2.  Growth inhibition rate (%) of the target compounds 6a~6t at 10 and 100 μg/mL^a

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  Compd.	B. campestris			E. crusgalli
  	10 mg/L	100 mg/L		10 mg/L	100 mg/L
  Flumioxazin	57.8	63.0		95.1	97.5
  5	63.8	72.5		0	20
  6a	39.8	79.4		0	22.9
  6b	14.2	70.4		0	0
  6c	18.2	74.2		0.9	4.6
  6d	30.2	81.9		0	11.9
  6e	15.7	78.9		6.4	19.3
  6f	20.2	69.4		0	0
  6g	18.2	72.1		3.4	17.4
  6h	7.6	72.9		4.6	6.4
  6i	0	54.1		0	0
  6j	10.2	78.9		0	0
  6k	22.2	83.9		0	14.4
  6l	19.2	69.4		0.9	4.6
  6m	7.6	63.9		0.9	2.8
  6n	47.3	77.9		0	26.6
  6o	0	63.9		14.4	31.5
  6p	53.1	86.7		11.9	33.9
  6q	43.3	88		0	0
  6r	29	77.4		0	0.9
  6s	13.2	76.7		0.9	8.2
  6t	25.2	63.4		0	0
  a Flumioxazin, a current commercial herbicide was used as a positive control.

  As the bioassay results showed, at 100 μg/mL, all the target compounds except 6i (R＝p-BrC₆H₄) exhibited better herbicidal activity against the root-growth of rape (B. campestris) with 63.4%~88.0% inhibition rates than that of the commercial herbicide of flumioxazin with inhibition rate of 63.0%, in which compounds 6q (R＝α-pyridyl), 6p (R＝cyclopropyl), 6k (R＝m-OMeC₆H₄) and 6d (R＝p-MeC₆H₄) held growth inhibition rates of 88.0%, 86.7%, 83.9%, and 81.9%, respectively. Besides, compared with the intermediate 5, the inhibitory activities of most target compounds against the root-growth of rape (B. campestris) were enhanced after etherification at 100 μg/mL. Compound 6q (R＝α-pyridyl) was a lead compound worthy of further study.

  2.4   CoMFA analysis

  Comparative molecular field analysis (CoMFA) method has become a powerful tool for the discovery of new drug.^[37] In this work, the CoMFA model with 0.509 of cross-validated coefficient (q²), 0.985 of correlation coefficient (r²), 89.985 of Fischer ratio (F) and 0.061 of standard error of estimate (S) was built based on the antifungal activity against P. piricola (Table 3). Meanwhile, the experimental and predicted ED values for the compounds 6a~6o were presented in Table 4 and the scatter diagram was shown in Figure 1, where all data were concentrated near the X＝Y line. These results suggested that the model was reliable and effective.

  Table 3

  

  Table 3.  Summary of CoMFA analysis

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  q2	r2	S	N	F	Contribution/%
  					Steric	Electrostatic
  0.509	0.985	0.061	6	89.985	74.6	25.4

  Table 4

  

  Table 4.  ED values of experimental and predicted activities^a

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  Compd.	ED	ED''	Residue
  6a	－1.19	－1.28	0.09
  6b	－2.50	－2.43	－0.07
  6c	－1.95	－1.98	0.03
  6d	－2.06	－2.04	－0.02
  6e	－1.56	－1.49	－0.07
  6f	－2.03	－2.05	0.02
  6g	－2.40	－2.36	－0.04
  6h	－2.06	－2.04	－0.02
  6i	－2.28	－2.30	0.02
  6j	－2.04	－2.08	0.04
  6k	－2.08	－2.06	－0.02
  6l	－1.83	－1.80	－0.03
  6m	－2.76	－2.82	0.06
  6n	－2.09	－2.06	－0.03
  6o	－2.43	－2.46	0.03
  a ED＝experimental value, ED''＝predictive value of ED.

  Figure 1

  

  Figure 1.  Predicted ED value of CoMFA model vs experimental ED value

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  The steric and electrostatic contribution maps of CoMFA were shown in Figure 2. The contribution rates of the steric and electrostatic fields were 74.6% and 25.4%, respectively, indicating that the steric field of the compounds had a greater influence on the antifungal activity against P. piricola. In Figure 2a, there were some green regions located around the 2, 3, or 4-position of the benzene ring, indicating that the bulky groups at these positions were favorable to enhance the antifungal activity. This was in consistent with experimental result, for example, compounds 6i (R＝p-BrC₆H₄), 6j (R＝p-MeSC₆H₄), and 6l (R＝p-vinyl-C₆H₄) exhibited better antifungal activity than 6g (R＝p-ClC₆H₄). In Figure 2b, the electrostatic contours were displayed in distinguishable colors: blue suggested that increase of positive charge was favorable for the increase of activity, red was the opposite. Therefore, the target compounds bearing an electron-withdrawing group at the 2 or 4-position of the benzene ring and an electron-donating group at the 3-position displayed higher activity. For instance, compounds 6l (R＝p-vinyl-C₆H₄) and 6e (R＝o-ClC₆H₄) showed higher antifungal activity against P. piricola than compounds 6j (R＝p-MeSC₆H₄) and 6b (R＝o-MeC₆H₄). In addition, compound 6c (R＝m-MeC₆H₄) displayed better activity than compounds 6f (R＝m-ClC₆H₄) and 6h (R＝m-FC₆H₄). Based on the results of 3D-QSAR analysis above, a new compound (Figure 3) was designed and predicted the ED by the established CoMFA model. As a result, the predicted ED was high to －1.40, showing excellent antifungal activity, however, which need to verify in experiment.

  Figure 2

  

  Figure 2.  Contours of steric contribution (a) and electrostatic contribution (b)

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  Figure 3

  

  Figure 3.  Newly designed molecule of 3-(((5-((2, 2-dimethyl-3- propylcyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazol-3-yl)thio)-methyl)-N, N-bis(2-methylpentan-2-yl)aniline

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  2.5   Three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis

  In this study, the CoMFA model was built using SYBYL-X 2.1.1 software (Tripos, Inc., St. Louis, MO, USA) according to the reported method.^[7] The antifungal activity against P. piricola was expressed in terms of activity factor (ED) by the formula ED＝log{I/[(100－I)×M_W]}, where I was the percentage inhibition at 50 μg/mL and M_W was the molecular weight of the tested compounds. Complete conformational optimization of each structure was performed using a conjugate gradient procedure based on the Tripos force field. The molecular superimposition was carried out using compound 6a as a template, in which the atoms marked with an asterisk constituted the common superimposed skeleton (Figure 4). The superposed effect of fifteen optimized compounds was shown in Figure 5. The CoMFA values were calculated by the QSAR module. Then, the partial least-squares (PLS) method was applied to establish the 3D-QSAR model, in which the CoMFA values were used as independent variables and ED values were used as dependent variables. The cross-validation with the leave-one-out method was carried out to obtain the cross-validated coefficient (q²) and the optimal number of components. The non-cross-validation analysis under the optimal number of components was performed. The correlation between CoMFA and ED values was indicated by the squared correlation coefficient (r²), and the prediction capability was indicated by the cross-validated coefficient (q²).

  Figure 4

  

  Figure 4.  Asterisk skeleton of title compounds

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  Figure 5

  

  Figure 5.  Superposition modes of compounds

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  3.   Experimental Section

  3.1   General

  The GC analysis was conducted on an Agilent 6890 GC (Agilent Technologies Inc., Santa Clara, CA, USA) equipped with column HP-1 (30 m, 0.530 mm, 0.88 μm). IR spectra were recorded on a Nicolet iS50 FT-IR spectrometer (Thermo Scientific Co., Ltd., Madison, WI, USA) by KBr pellet method. NMR spectra were recorded in CDCl₃ solvent on a Bruker Avance III HD 600 MHz spectrometer (Bruker Co., Ltd., Zurich, Switzerland) with TMS as an internal standard. MS spectra were obtained by means of the electrospray ionization (ESI) method on a TSQ Quantum Access MAX HPLC-MS instrument (Thermo Scientific Co., Ltd., Waltham, MA, USA). The UV spectra were measured on a Shimadzu UV-1800 spectrophotometer (Shimadzu Corp., Kyoto, Japan). Elemental analyses were measured using a PE 2400 II elemental analyzer (Perkin-Elmer Instruments Co., Ltd., USA). The HPLC analysis was performed on a Waters 1525 instrument (Waters Co., Ltd., USA) equipped with column SunFire C18 5 μm (4.6 mm×150 mm) and 2998 diode array detector. Melting points were determined on a MP420 automatic melting point apparatus (Hanon Instruments Co., Ltd., Jinan, China) and were not corre- cted. 3-Carene (GC purity 98%, racemate) was provided by Wuzhou Pine Chemicals Co., Ltd., Wuzhou, Guangxi, China. Other reagents were purchased from commercial suppliers and used as received.

  3.2   Synthesis of 2-(2, 2-dimethyl-3-(2-oxopropyl)- cyclopropyl) acetic acid (2)

  Compound 2 was prepared by oxidation of 3-carene under alkaline conditions.^[39] 3-Carene (100 mL, 629.0 mmol) was dissolved in 500 mL of tert-butanol and 1000 mL of water. To this mixture were added sodium periodate (490.0 g, 2.29 mol) and ruthenium chloride hydrate (2.2 g, 4.0 mmol). The mixture was stirred vigorously for 2 h at 45 ℃, and for another 1.5 h at 55 ℃. Then, the mixture was cooled to 30 ℃ and filtered, and the residue was washed with EtOAc (500 mL). After the EtOAc layer was separated, the filtrate was extracted with EtOAc (400 mL×3). All the EtOAc phases were combined, washed with brine (400 mL), and concentrated by removal of solvent. The concentrate was alkalized to pH 10 with dilute aqueous NaOH, and the organic phase was washed with appropriate EtOAc and abandoned. The left aqueous phase was acidified with dilute hydrochloric acid to pH 3 and extracted with EtOAc (200 mL×3). The extract was washed with brine, dried over anhydrous Na₂SO₄, and evaporated in vacuo to obtain the product as a brown liquid with yield of 68.5%. b.p. 158.0~165.0 ℃/0.67 kPa. ¹H NMR (600 MHz, CDCl₃) δ: 2.45~2.38 (m, 2H, C²-H), 2.33~2.24 (m, 2H, C⁶-H), 2.19 (s, 3H, C⁸-H), 1.14 (s, 3H, C⁹-H or C¹⁰-H), 0.97 (q, J＝8.1 Hz, 2H, C³-H and C⁵-H), 0.94 (s, 3H, C⁹-H or C¹⁰-H); ¹³C NMR (150 MHz, CDCl₃) δ: 208.9 (C⁷), 179.2 (C¹), 39.3, 30.1, 29.6, 28.4 (C⁹ or C¹⁰), 21.2, 17.3, 14.9 (C⁹ or C¹⁰); IR (KBr) ν: 3500~2500 (COOH), 2956 (w), 2869 (w), 1712 (s, C＝O) cm^－1; ESI-MS m/z: 185.05 [M+H]⁺. Anal. calcd for C₁₀H₁₆O₃: C 65.19, H 8.75; found C 65.12, H 8.72.

  3.3   Synthesis of 2-(2, 2-dimethyl-3-propylcyclopro- pyl)acetic acid (3)

  Compound 3 was prepared by our previous work.^[40] KOH (14.0 g, 245.0 mmol) was added to ethylene glycol (50 mL) under stirring and was completely dissolved. To the mixture were added compound 2 (12.9 g, 70.0 mmol) and 40 mL of hydrazine hydrate (w＝80%), respectively. The reaction mixture was heated and refluxed at 160 ℃ for 3 h while a water segregator was employed to remove the excess water and hydrazine for promoting the reaction. Then, the reaction mixture was continuously heated to 180 ℃ and refluxed 8 h. When the reaction was completed, the mixture was cooled to room temperature, and acidified with 10.0% (w) aqueous HCl to pH 3.0. Afterwards, the mixture was extracted several times with cyclohexane. The combined organic phases were washed with brine, dried over anhydrous sodium sulfate, and evaporated in vacuo to obtain the product as yellow liquid with yield of 55.8%. b.p. 110.0~115.0 ℃/0.67 kPa; ¹H NMR (600 MHz, CDCl₃) δ: 2.35~2.27 (m, 2H, C²-H), 1.35 (tq, J＝13.2, 6.7, 6.2 Hz, 2H, C⁷-H), 1.26 (td, J＝14.3, 6.4 Hz, 1H, C⁶-H_a), 1.17 (td, J＝14.1, 8.2 Hz, 1H, C⁶-H_b), 1.07 (s, 3H, C⁹-H or C¹⁰-H), 0.93 (s, 3H, C⁹-H or C¹⁰-H), 0.91 (t, J＝7.3 Hz, 3H, C⁸-H), 0.85~0.81 (m, 1H, C³-H), 0.58~0.53 (m, 1H, C⁵-H); ¹³C NMR (150 MHz, CDCl₃) δ: 180.3 (C¹), 29.9 (C²), 28.9 (C⁹ or C¹⁰), 26.5 (C⁶), 26.2 (C⁵), 23.1 (C⁷), 21.5 (C³), 17.1 (C⁴), 14.8 (C⁹ or C¹⁰), 14.0 (C⁸); IR (KBr) ν: 3500~2500 (COOH), 2961.7, 2866.4, 1718.0 (C＝O) cm^－1; ESI-MS m/z: 169.03 [M－H]^－. Anal. calcd for C₁₀H₁₈O₂: C 70.55, H 10.66; found C 70.52, H 10.63.

  3.4   Synthesis of 5-((2, 2-dimethyl-3-propylcyclopro- pyl)methyl)-4-methyl-2, 4-dihydro-3H-1, 2, 4-triazole-3-thione (5)

  Under anhydrous atmosphere, a solution of SOCl₂ (5.7 g, 48.0 mmol, w＝99.0%) in benzene (10 mL) was added slowly to a solution of compound 3 (6.8 g, 40.0 mmol) in benzene (15 mL) at room temperature. Subsequently, three drops of N, N-dimethylformamide (DMF) were added, and the mixture was refluxed for 5 h under stirring. Afterwards, the reaction solution was distilled at atmospheric pressure to remove the low boiling components, and evaporated in vacuo to give the intermediate 4 as yellow liquid with yield of 52.5% (b.p. 70.0~72.0 ℃/0.67 kPa). Under anhydrous atmosphere, in an ice-water bath, to a stirred mixture of N-methylhydrazinecarbothioamide (1.2 g, 11.4 mmol) in CH₂Cl₂ (30 mL) were added slowly five drops of trimethylamine and then a solution of 4 (1.9 g, 10.0 mmol) in CH₂Cl₂ (15 mL). When the addition was completed, the mixture was stirred for 1 h in an ice-water bath, and for another 1.5 h at room temperature. After quenching with HCl (5.0 mL, 2.88 mol/L), the reaction mixture was washed with 15 mL of deionized water, and dried over anhydrous Na₂SO₄. Then, CH₂Cl₂ was removed in vacuo, and the crude product was purified by silica gel column chromatography (ethyl acetate/petroleum ether, V:V＝1:6) to obtain intermediate 5 as colorless solid. Yield 64.5%, HPLC purity 98.72%. m.p. 108.4~109.3 ℃; UV-Vis (EtOH) λ_max [log ε/(L•mol^－1•cm^－1)]: 253.5 (4.30) nm; ¹H NMR (600 MHz, CDCl₃) δ: 11.89 (s, NH), 3.56 (s, 3H, NCH₃), 2.57 (d, J＝7.1 Hz, 2H, C⁶-H), 1.41~1.28 (m, 3H, C¹¹-H, C¹⁰-Ha), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.09 (s, 3H, C¹³-H or C¹⁴-H), 0.97 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C₁₂-H), 0.85 (dt, J＝8.4, 7.0 Hz, 1H, C⁷-H), 0.65 (td, J＝8.5, 6.0 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 167.4 (C³), 153.2 (C⁵), 30.4 (N-CH₃), 28.9 (C⁶), 26.4 (C¹⁰, C¹³ or C¹⁴), 23.0, 22.0, 21.5, 17.5, 14.8 (C¹³ or C¹⁴), 14.0; IR (KBr) ν: 3116 (s, N—H), 3057 (m), 2962 (s), 2926 (s), 2854 (m), 1575 (s, N—C＝S, I), 1346 (s, N—C＝S, II), 1081 (m, N—C＝S, III), 1507 (s, C＝N), 1453 (m), 1376 (w), 1147 (w) cm^－1; ESI-MS m/z: 239.98 [M+H]⁺. Anal. calcd for C₁₂H₂₁N₃S: C 60.21, H 8.84, N 17.55; found C 60.20, H 8.85, N 17.52.

  3.5   General procedure for synthesis of 6a~6t

  Compound 5 (240.0 mg, 1.0 mmol) and potassium hydroxide (120.0 mg, 2.0 mmol) were mixed in anhydrous ethanol (15 mL). Then the mixture was stirred and refluxed for 2 h. Afterwards, a solution of alkyl halide (1.5 mmol) in 8 mL of EtOH was slowly added to the mixture and continuously refluxed for 30 min. The reaction process was monitored by thin-layer chromatography (TLC). After the solvent EtOH was removed by rotary evaporation, the residue was acidified with HCl (w＝10.0%) to pH＝3, and extracted with EtOAc. The separated organic phase was washed with brine, dried over anhydrous Na₂SO₄, and concentrated under reduced pressure to give the crude product, which was purified by silica gel column chromatography to afford the target compounds 6a~6t.

  3-(Benzylthio)-5-((2, 2-dimethyl-3-propylcyclopropyl)-methyl)-4-methyl-4H-1, 2, 4-triazole (6a): Pale yellow syrup, yield 86.5%, HPLC purity 97.87%. ¹H NMR (600 MHz, CDCl₃) δ: 7.28~7.23 (m, 3H, ArH), 7.21 (dt, J＝6.9, 1.9 Hz, 2H, ArH), 4.27 (s, 2H, C¹⁵-H), 3.13 (s, 3H, NCH₃), 2.63~2.54 (m, 2H, C⁶-H), 1.43~1.31 (m, 3H, C¹¹-H, C¹⁰-H_a), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.80 (dt, J＝8.9, 6.8 Hz, 1H, C⁷-H), 0.59 (td, J＝8.6, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.6 (C⁵), 149.3 (C³), 137.2, 129.0 (C¹⁸, C²⁰), 128.6 (C¹⁷, C²¹), 127.7, 39.3, 29.8, 29.0 (NCH₃), 26.5, 23.1, 23.0, 21.0, 17.5, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3066 (w, cyclopropyl), 3033 (w, cyclopropyl, Ar—H), 2959 (s), 2932 (s), 2861 (m), 1510 (w), 1495 (m, Ar), 1474 (s, C＝N), 1453 (S), 1382 (w), 687 (w, C—S—C) cm^－1; ESI-MS m/z: 329.97 [M+H]⁺. Anal. calcd for C₁₉H₂₇N₃S: C 69.26, H 8.26, N 12.75; found C 69.25, H 8.21, N 12.76.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl- 5-((2-methylbenzyl)thio)-4H-1, 2, 4-triazole (6b): Yellow syrup, yield 88.7%, HPLC purity 96.82%. ¹H NMR (600 MHz, CDCl₃) δ: 7.19~7.13 (m, 2H, C¹⁸-H, C²⁰-H), 7.03 (td, J＝8.5, 5.6, 2.7 Hz, 1H, C²¹-H), 7.01~6.97 (m, 1H, C¹⁹-H), 4.28 (s, 2H, C¹⁵-H), 3.06 (s, 3H, NCH₃), 2.62~2.54 (m, 2H, C⁶-H), 2.39 (s, 3H, C²²-H), 1.41~1.31 (m, 3H, C¹¹-H, C¹⁰-H_a), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.3 Hz, 3H, C¹²-H), 0.79 (dt, J＝8.8, 6.8 Hz, 1H, C⁷-H), 0.59 (td, J＝8.6, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.61 (C⁶), 149.3 (C¹⁵), 136.8, 134.9, 130.6, 129.8, 128.1, 126.1, 37.5, 29.7, 29.0 (NCH₃), 26.5, 23.1, 23.0, 21.0, 19.0, 17.5, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3068 (w, cyclopropyl, Ar—H), 2956 (s), 2926 (s), 2859 (m), 1510 (m), 1498 (m, Ar), 1468 (s, C＝N), 1423 (m), 1378 (m), 685 (w, C—S—C) cm^－1; ESI-MS m/z: 344.07 [M+H]⁺. Anal. calcd for C₂₀H₂₉N₃S: C 69.93, H 8.51, N 12.23; found C 69.94, H 8.50, N 12.21.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl- 5-((3-methylbenzyl)thio)-4H-1, 2, 4-triazole (6c): Pale yellow solid, yield 90.5%, HPLC purity 97.64%. m.p. 58.2~58.9 ℃; ¹H NMR (600 MHz, CDCl₃) δ: 7.14 (t, J＝7.8 Hz, 1H, C²⁰-H), 7.07~7.04 (m, 2H, C²¹-H, C¹⁷-H), 7.01 (d, J＝7.6 Hz, 1H, C¹⁹-H), 4.25 (s, 2H, C¹⁵-H), 3.17 (s, 3H, NCH₃), 2.73~2.43 (m, 2H, C⁶-H), 2.30 (S, 3H, C²²-H), 1.41~1.30 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.24~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.81 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.60 (td, J＝8.6, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.5 (C⁵), 149.5 (C³), 138.3, 137.0, 129.7, 128.5, 128.4, 126.0, 39.1, 29.8, 29.0 (NCH₃), 26.5, 23.1, 23.0, 21.3, 21.0, 17.4, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 2958 (s), 2925 (s), 2866 (s), 1735 (m), 1607 (w, Ar), 1592 (w), 1524 (m, Ar), 1488 (s, C＝N), 1470 (m), 1375 (w), 700 (w, C—S—C) cm^－1; ESI-MS m/z: 344.06 [M+H]⁺. Anal. calcd for C₂₀H₂₉N₃S: C 69.93, H 8.51, N 12.23; found C 69.90, H 8.52, N 12.24.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl- 5-((4-methylbenzyl)thio)-4H-1, 2, 4-triazole (6d): Yellow syrup, yield 91.0%, HPLC purity 98.23%. ¹H NMR (600 MHz, CDCl₃) δ: 7.11 (d, J＝8.0 Hz, 2H, C¹⁷-H, C²¹-H), 7.06 (d, J＝8.0 Hz, 2H, C¹⁸-H, C²⁰-H), 4.25 (s, 2H, C¹⁵-H), 3.15 (s, 3H, N-CH₃), 2.72~2.50 (m, 2H, C⁶-H), 2.31 (s, 3H, C²²-H), 1.43~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.1 Hz, 3H, C¹²-H), 0.80 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.59 (td, J＝8.6, 5.3 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.49 (C⁵), 149.48 (C³), 137.4, 134.1, 129.3 (C¹⁸, C²⁰), 128.9 (C¹⁷, C²¹), 38.9, 29.9, 29.0 (N-CH₃), 26.5, 23.1, 23.0, 21.1, 21.0, 17.4, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 2961 (s), 2925 (s), 2860 (s), 1620 (w, Ar), 1522 (m, Ar), 1474 (s, C＝N), 1423 (m), 1379 (m), 686 (w, C—S—C) cm^－1; ESI-MS m/z: 343.99 [M+H]⁺. Anal. calcd for C₂₀H₂₉N₃S: C 69.93, H 8.51, N 12.23; found C 69.92, H 8.53, N 12.20.

  3-((2-Chlorobenzyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6e): Yel- low syrup, yield 88.0%, HPLC purity 97.54%. ¹H NMR (600 MHz, CDCl₃) δ: 7.37 (dt, J＝7.2, 1.2 Hz, 1H, ArH), 7.20 (td, J＝7.4, 1.4 Hz, 2H, ArH), 7.13~7.07 (m, 1H, ArH), 4.39 (s, 2H, C¹⁵-H), 3.17 (s, 3H, N-CH₃), 2.62~2.54 (m, 2H, C⁶-H), 1.41~1.30 (m, 3H, C₁₁-H and C¹⁰-H_a), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 2H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.81 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.59 (td, J＝8.6, 5.5 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.7 (C⁵), 149.0 (C³), 135.0, 134.1, 131.2, 129.7, 129.2, 126.9, 36.8, 29.8, 29.0 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.4, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3066 (w, cyclopropyl, Ar—H), 2953 (s), 2929 (s), 2866 (m), 1507 (m, Ar), 1474 (C＝N), 1447 (m), 1382 (w), 684 (C—S—C) cm^－1; ESI-MS m/z: 363.99 [M+H]⁺. Anal. calcd for C₁₉H₂₆Cl- N₃S: C 62.70, H 7.20, N 11.55; found C 62.71, H 7.18, N 11.54.

  3-((3-Chlorobenzyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6f): Yellow syrup, yield 88.6%, HPLC purity 98.37%. ¹H NMR (600 MHz, CDCl₃) δ: 7.27~7.24 (m, 1H, C¹⁷-H), 7.22 (dt, J＝7.8, 1.5 Hz, 1H, C²¹-H), 7.19 (td, J＝7.7, 1.5 Hz, 1H, C¹⁹-H), 7.16~7.12 (m, 1H, C²⁰-H), 4.27 (s, 2H, C¹⁵-H), 3.23 (s, 3H, N-CH₃), 2.57~2.64 (m, 2H, C⁶-H), 1.40~1.32 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.24~1.17 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.83 (dt, J＝8.8, 6.9 Hz, 1H, C⁷-H), 0.60 (td, J＝8.5, 5.3 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.7 (C⁵), 149.0 (C³), 139.3, 134.3, 129.9, 129.0, 127.8, 127.2, 38.2, 29.9, 28.93 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.5, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3065 (w, cyclopropyl, Ar—H), 2958 (s), 2926 (s), 2861 (s), 1602 (m, Ar), 1577 (m), 1510 (m, Ar), 1475 (s, C＝N), 1433 (m), 1378 (w) cm^－1; ESI-MS m/z: 364.01 [M+H]⁺. Anal. calcd for C₁₉H₂₆ClN₃S: C 62.70, H 7.20, N 11.55; found C 62.69, H 7.19, N 11.52.

  3-((4-Chlorobenzyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6g): Red- dish brown syrup, yield 90.5%, HPLC purity 96.79%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 224.5 (4.14) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.25~7.18 (m, 4H, ArH), 4.27 (s, 2H, C¹⁵-H), 3.21 (s, 3H, NCH₃), 2.65~2.56 (m, 2H, C⁶-H), 1.41~1.30 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.24~1.15 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.80 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.60 (td, J＝8.6, 5.4 Hz, 1H, C⁵-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.6 (C⁵), 149.0 (C³), 135.8, 133.5, 130.4 (C¹⁷, C²¹), 128.7 (C¹⁸, C²⁰), 38.0, 29.9, 28.9 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.5, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 2955 (s), 2931 (s), 2863 (m), 1598 (w, Ar), 1494 (s, Ar), 1473 (s, C＝N), 1429 (w), 1381 (w), 684 (C—S—C) cm^－1; ESI-MS m/z: 363.99 [M+H]⁺. Anal. calcd for C₁₉H₂₆ClN₃S: C 62.70, H 7.20, N 11.55; found C 62.66, H 7.22, N 11.53.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-5-((3-fluorobenzyl)thio)-4-methyl-4H-1, 2, 4-triazole (6h): Yellow syrup, yield 87.3%, HPLC purity 97.46%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 257.5 (3.36) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.22 (td, J＝7.9, 5.9 Hz, 1H, C²⁰-H), 7.02 (dt, J＝7.7, 1.3 Hz, 1H, C²¹-H), 6.98 (dt, J＝9.6, 2.1 Hz, 1H, C¹⁹-H), 6.94 (td, J＝8.4, 2.7 Hz, 1H, C¹⁷-H), 4.29 (s, 2H, C¹⁵-H), 3.23 (s, 3H, N-CH₃), 2.65~2.56 (m, 2H, C⁶-H), 1.41~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.24~1.17 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.82 (dt, J＝8.8, 6.9 Hz, 1H, C⁷-H), 0.60 (td, J＝8.7, 5.4 Hz, 1H, C⁵-H); ¹³C NMR (150 MHz, CDCl₃) δ: 162.7 (d, J＝247.0 Hz, C¹⁸), 156.7 (C⁵), 149.1 (C³), 139.7 (d, J＝7.3 Hz, C¹⁶), 130.1 (d, J＝8.3 Hz, C²⁰), 124.7 (d, J＝2.9 Hz, C²¹), 115.9 (d, J＝21.8 Hz, C¹⁷), 114.6 (d, J＝21.0 Hz, C¹⁹), 38.3, 29.9, 28.9 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.5, 14.8 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 2952 (s), 2872 (m), 1738 (s), 1619 (w, Ar), 1491 (m, Ar), 1470 (s, C＝N), 1450 (s), 1381 (w), 681 (w, C—S—C) cm^－1; ESI-MS m/z: 348.04 [M+H]⁺. Anal. calcd for C₁₉H₂₆FN₃S: C 65.67, H 7.54, N 12.09; found C 65.63, H 7.52, N 12.13.

  3-((4-Bromobenzyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6i): Yellow syrup, yield 86.5%, HPLC purity 96.95%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 224.0 (4.18) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.41~7.36 (m, 2H, C¹⁸-H, C¹⁹-H), 7.16~7.11 (m, 2H, C¹⁷-H, C²¹-H), 4.26 (s, 2H, C¹⁵-H), 3.21 (s, 3H, N-CH₃), 2.64~2.55 (m, 2H, C⁶-H), 1.43~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.24~1.17 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.80 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.60 (td, J＝8.6, 5.4 Hz, 1H, C⁹-H), ¹³C NMR (150 MHz, CDCl₃) δ: 156.6 (C⁵), 149.0 (C³), 136.3, 131.7 (C¹⁸, C²⁰), 130.7 (C¹⁷, C²¹), 121.6, 38.1, 29.9, 29.0 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.5, 14.9 (C₁₃, C₁₄), 14.1; IR (KBr) ν: 2958 (s), 2931 (s), 2869 (s), 1735 (s), 1592 (w, Ar), 1512 (m, Ar), 1473 (s, C＝N), 683 (w, C—S—C) cm^－1; ESI-MS m/z: 407.96 [M+H]⁺. Anal. calcd for C₁₉H₂₆BrN₃S: C 55.88, H 6.42, N 10.29; found C 55.86, H 6.47, N 10.29.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl- 5-((4-(methylthio)benzyl)thio)-4H-1, 2, 4-triazole (6j): Yellow syrup, yield 91.6%, HPLC purity 97.64%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 266.5 (4.19) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.14 (td, J＝8.5, 6.5 Hz, 4H, ArH), 4.25 (s, 2H, C¹⁵-H), 3.21 (s, 3H, N-CH₃), 2.64~2.55 (m, 2H, C⁶-H), 2.45 (s, 3H, C²²-H), 1.42~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.26~1.16 (m, 1H, C¹⁰-b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.3 Hz, 3H, C¹²-H), 0.80 (td, J＝8.9, 6.9 Hz, 1H, C⁷-H), 0.60 (dt, J＝8.6, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.5 (C⁵), 149.3 (C³), 138.1, 133.9, 129.5 (C¹⁸, C²⁰), 126.5 (C¹⁹, C²¹), 38.6, 29.9, 29.0 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.4, 15.7, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 2958 (s), 2925 (s), 2866 (m), 1601 (w, Ar), 1497 (s, Ar), 1470 (s, C＝N), 1423 (w), 1378 (w), 683 (w, C—S—C) cm^－1; ESI-MS m/z: 376.05 [M+H]⁺. Anal. calcd for C₂₀H₂₉N₃S: C 63.96, H 7.78, N 11.19; found C 63.93, H 7.75, N 11.18.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-5-((3-methoxybenzyl)thio)-4-methyl-4H-1, 2, 4-triazole (6k): Yellow syrup, yield 89.8%, HPLC purity 98.21%. UV-vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 278.5 (3.47) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.17 (tt, J＝7.9, 1.8 Hz, 1H, ArH), 6.84~6.77 (m, 2H, ArH), 6.76 (q, J＝2.0 Hz, 1H, Ar-H), 4.25 (s, 2H, C¹⁵-H), 3.75 (s, 3H, C²²-H), 3.21 (s, 3H, N-CH₃), 2.64~2.55 (m, 2H, C⁶-H), 1.42~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.80 (td, J＝8.9, 6.9 Hz, 1H, C⁷-H), 0.60 (dt, J＝8.6, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 159.7 (C⁵), 156.6, 149.3 (C³), 138.6, 129.6, 121.2, 114.1, 113.6, 55.2, 39.2, 29.9, 28.9 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.4, 14.9 (C¹³, C¹⁴), 14.1 (C₁₂); IR (KBr) ν: 2958 (s), 2931 (s), 2863 (m), 1601 (m), 1583 (m, Ar), 1497 (m, Ar), 1470 (s, C＝N), 1440 (w), 1375 (w), 1274 (s, C—O—C), 681 (w, C—S—C) cm^－1; ESI-MS m/z: 360.06 [M+H]⁺. Anal. calcd for C₂₀H₂₉N₃OS: C 66.81, H 8.13, N 11.69; found C 66.80, H 8.12, N 11.72.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl- 5-((4-vinylbenzyl)thio)-4H-1, 2, 4-triazole (6l): Yellow syrup, yield 88.9%, HPLC purity 97.82%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 278.0 (3.41) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.29 (d, J＝8.1 Hz, 2H, C¹⁸-H, C²⁰-H), 7.17 (d, J＝8.1 Hz, 2H, C¹⁷-H, C²¹-H), 6.66 (dd, J＝17.6, 10.9 Hz, 1H, C²²-H), 5.71 (d, J＝17.6 Hz, 1H, C²³-H_a), 5.24 (d, J＝10.9 Hz, 1H, C²³-H_b), 4.26 (s, 2H, C¹⁵-H), 3.15 (s, 3H, N-CH₃), 2.64~2.54 (m, 2H, C⁶-H), 1.44~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.23~1.16 (m, 1H, C¹⁰-H_b), 1.06 (s, 3H, C¹³-H or C¹⁴-H), 0.97 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.79 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.58 (td, J＝8.6, 5.3 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.6 (C⁵), 149.2 (C³), 137.0, 136.7, 136.2, 129.2 (C¹⁸, C²⁰), 126.4 (C¹⁷, C²¹), 114.2, 39.0, 29.9, 29.0 (N-CH₃), 26.5, 23.1, 23.0, 21.0, 17.4, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3089 (w), 2955 (s), 2928 (s), 2863 (s), 1631 (w, C＝C), 1512 (s, Ar), 1470 (s, C＝N), 1425 (m), 1375 (w), 683 (w, C—S—C) cm^－1; ESI-MS m/z: 356.06 [M+H]⁺. Anal. calcd for C₂₀H₂₉N₃OS: C 70.94, H 8.22, N 11.82; found C 70.92, H 8.23, N 11.85.

  3-((2, 6-Dichlorobenzyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6m): Pale syrup, yield 84.2%, HPLC purity 97.31%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 253.5 (4.23), 205.5 (4.39) nm; ¹H NMR (600 MHz, CDCl₃) δ: 7.29 (d, J＝8.0 Hz, 2H, C¹⁸-H, C²⁰-H), 7.17 (dd, J＝8.5, 7.6 Hz, 1H, C¹⁹-H), 4.50 (s, 2H, C¹⁵-H), 3.30 (s, 3H, N-CH₃), 2.70~2.60 (m, 2H, C⁶-H), 1.43~1.33 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.25~1.18 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 1.01 (s, 3H, C¹³-H or C¹⁴-H), 0.94~0.91 (m, 3H, C¹²-H), 0.85 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.61 (td, J＝8.7, 5.5 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 157.0 (C⁵), 148.5 (C³), 135.8 (C¹⁷, C²¹), 133.3, 129.4 (C¹⁸, C²⁰), 128.4, 35.1, 30.0, 29.0 (N-CH₃), 26.5, 23.1 (C₉, C₁₁), 21.2, 17.5, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3077 (w, cyclopropyl, Ar—H), 2958 (s), 2925 (s), 2860 (m), 1580 (w, Ar), 1509 (w, Ar), 1473 (m, C＝N), 1438 (s), 1378 (w), 683 (w, C—S—C) cm^－1; ESI-MS m/z: 397.96 [M+H]⁺. Anal. calcd for C₁₉H₂₅Cl₂N₃S: C 57.28, H 6.33, N 10.55; found C 57.27, H 6.30, N 10.51.

  3-((2, 6-Difluorobenzyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6n): Yel- low syrup, yield 91.6%, HPLC purity 96.97%. ¹H NMR (600 MHz, CDCl₃) δ: 7.24 (tt, J＝8.4, 6.5 Hz, 1H, C¹⁹-H), 6.88~6.83 (m, 2H, C¹⁸-H, C²⁰-H), 4.28 (s, 2H, C¹⁵-H), 3.38 (s, 3H, N-CH₃), 2.70~2.61 (m, 2H, C⁶-H), 1.43~1.32 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.26~1.18 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 1.00 (s, 3H, C¹³-H or C¹⁴-H), 0.93 (t, J＝7.2 Hz, 3H, C¹²-H), 0.86 (dt, J＝8.9, 6.9 Hz, 1H, C⁷-H), 0.61 (td, J＝8.6, 5.5 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 161.2 (dd, J＝250.6, 7.4 Hz, C¹⁷, C²¹), 156.90 (C⁵), 148.6 (C³), 129.7 (t, J＝10.2 Hz, C¹⁹), 113.2 (t, J＝19.1 Hz, C¹⁶), 111.4 (dd, J＝20.8, 4.6 Hz, C¹⁸, C²⁰), 30.0, 29.0 (N-CH₃), 26.5 (d, J＝4.0 Hz, C¹⁰), 26.1 (t, J＝3.2 Hz, C¹⁵), 23.1, 23.0, 21.1, 17.5, 14.8 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 2956 (m), 2932 (m), 2869 (w), 1629 (m), 1593 (m, Ar), 1471 (s, C＝N), 1423 (w), 1376 (w), 682 (w, C—S—C) cm^－1; ESI-MS m/z: 366.01 [M+H]⁺. Anal. calcd for C₁₉H₂₅F₂N₃S: C 62.44, H 6.89, N 11.50; found C 62.46, H 6.85, N 11.46.

  3-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-5-((2, 6-dimethylbenzyl)thio)-4-methyl-4H-1, 2, 4-triazole (6o): Pale yellow syrup, yield 90.3%, HPLC purity 97.83%. ¹H NMR (600 MHz, CDCl₃) δ: 7.08 (dd, J＝8.1, 6.9 Hz, 1H, C¹⁹-H), 7.00 (d, J＝7.5 Hz, 2H, C¹⁸-H, C²⁰-H), 4.39 (s, 2H, C¹⁵-H), 3.15 (s, 3H, N-CH₃), 2.68~2.57 (m, 2H, C⁶-H), 2.32 (s, 6H, C²²-H, C²³-H), 1.44~1.32 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.26~1.17 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 1.00 (s, 3H, C¹³-H or C¹⁴-H), 0.93 (t, J＝7.2 Hz, 3H, C¹²-H), 0.81 (dt, J＝8.9, 6.8 Hz, 1H, C⁷-H), 0.60 (td, J＝8.7, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.7 (C⁵), 149.8 (C³), 137.6, 132.7 (C¹⁷, C²¹), 128.4 (C¹⁸, C²⁰), 127.8, 33.6, 29.7, 29.0 (N-CH₃), 26.5, 23.1 (C⁹, C¹¹), 21.0, 19.6 (C²², C²³), 17.5, 14.9 (C¹³, C¹⁴), 14.1 (C₁₂); IR (KBr) ν: 2956 (s), 2929 (s), 2869 (m), 1590 (w, Ar), 1510 (w, Ar), 1471 (s, C＝N), 1426 (w), 1379 (w), 682 (w, C—S—C) cm^－1; ESI-MS m/z: 358.08 [M+H]⁺. Anal. calcd for C₂₁H₃₁N₃S: C 70.54, H 8.74, N 11.75; found C 70.54, H 8.76, N 11.72.

  3-((Cyclopropylmethyl)thio)-5-((2, 2-dimethyl-3-propyl-cyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazole (6p): Yel- low syrup, yield 91.5%, HPLC purity 97.39%. UV-Vis (EtOH) λ_max (log[ε/(L• mol^－1•cm^－1)]): 243.0 (3.36), 212.0 (3.94) nm; ¹H NMR (600 MHz, CDCl₃) δ: 3.52 (s, 3H, N-CH₃), 3.11 (d, J＝7.4 Hz, 2H, C¹⁵-H), 2.70~2.62 (m, 2H, C⁶-H), 1.42~1.32 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.26~1.20 (m, 1H, C¹⁰-H_b), 1.19~1.13 (m, 1H), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 1.00 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.88 (dt, J＝9.0, 6.8 Hz, 1H, C⁷-H), 0.63~0.56 (m, 3H), 0.28~0.22 (m, 2H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.3 (C⁵), 150.4 (C³), 39.8, 30.1, 29.0 (N-CH₃), 26.5, 23.1, 21.0, 17.5, 14.9 (C¹³, C¹⁴), 14.1, 11.1, 5.8 (C¹⁷, C¹⁸); IR (KBr) ν: 3083 (w, cyclopropyl, Ar—H), 2955 (s), 2931 (s), 2866 (m), 1515 (w, Ar), 1470 (s, C＝N), 1429 (w), 1378 (w), 681 (C—S—C) cm^－1; ESI-MS m/z: 294.06 [M+H]⁺. Anal. calcd for C₁₆H₂₇N₃S: C 65.48, H 9.27, N 14.32; found C 65.42, H 9.32, N 14.33.

  2-(((5-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazol-3-yl)thio)methyl)pyridine (6q): Reddish brown syrup, yield 82.5%, HPLC purity 98.08%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 263.5 (3.72), 210.5 (4.12) nm; ¹H NMR (600 MHz, CDCl₃) δ: 8.55 (d, J＝4.9 Hz, 1H, C¹⁸-H), 7.59 (td, J＝7.7, 1.8 Hz, 1H, C²⁰-H), 7.36 (dt, J＝7.8, 1.0 Hz, 1H, C²¹-H), 7.18 (ddd, J＝5.8, 4.9, 0.9 Hz, 1H, C¹⁹-H), 4.50 (s, 2H, C¹⁵-H), 3.35 (s, 3H, N-CH₃), 2.66~2.56 (m, 2H, C⁶-H), 1.42~1.30 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.25~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.84 (dt, J＝9.0, 6.9 Hz, 1H, C⁷-H), 0.59 (td, J＝8.6, 5.5 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.7, 156.5 (C⁵), 149.6, 149.5 (C³), 136.7, 123.7, 122.5, 39.6, 30.0 (C₆), 28.9 (N-CH₃), 26.5, 23.1, 23.0, 20.9, 17.4, 14.8 (C¹³, C¹⁴), 14.1 (C¹²); IR (KBr) ν: 3051 (w, ＝CH), 2959 (s), 2932 (s), 2863 (m), 1596 (w, Ar), 1572 (w, C＝C), 1474 (s, C＝N), 1438 (w), 1379 (w), 681 (w, C—S—C) cm^－1; ESI-MS m/z: 331.04 [M+H]⁺. Anal. calcd for C₁₈H₂₆N₄S: C 65.42, H 7.93, N 16.95; found C 65.41, H 7.92, N 16.94.

  4-(((5-((2, 2-Dimethyl-3-propylcyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazol-3-yl)thio)methyl)pyridine (6r): Pale yellow syrup, yield 80.6%, HPLC purity 97.22%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 260.0 (3.33), 205.5 (3.93) nm; ¹H NMR (600 MHz, CDCl₃) δ: 8.51 (d, J＝1.7 Hz, 1H, C¹⁸-H), 8.50 (d, J＝1.7 Hz, 1H, C²⁰-H), 7.24 (d, J＝1.7 Hz, 1H, C²¹-H), 7.23 (d, J＝1.7 Hz, 1H, C²¹-H), 4.30 (s, 2H, C¹⁵-H), 3.27 (s, 3H, N-CH₃), 2.65~2.55 (m, 2H, C⁶-H), 1.40~1.31 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.23~1.17 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.83 (dt, J＝9.0, 6.9 Hz, 1H, C⁷-H), 0.60 (td, J＝8.6, 5.5 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.7 (C⁵), 150.0 (C¹⁸, C²⁰), 148.6 (C³), 146.3, 123.9 (C¹⁷, C²¹), 36.9, 29.9, 28.9 (N-CH₃), 26.5, 23.1, 22.9, 20.9, 17.5, 14.8 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3033 (w, ＝CH), 2956 (s), 2926 (s), 2866 (m), 1605 (s, C＝N), 1566 (w, C＝C), 1471 (s, C＝N), 1417 (s), 1379 (w), 682 (w, C—S—C) cm^－1; ESI-MS m/z: 331.04 [M+H]⁺. Anal. calcd for C₁₈H₂₆N₄S: C 65.42, H 7.93, N 16.95; found C 65.43, H 7.90, N 16.97.

  2-Chloro-6-(((5-((2, 2-dimethyl-3-propylcyclopropyl)-methyl)-4-methyl-4H-1, 2, 4-triazol-3-yl)thio)methyl)-pyridine (6s): Yellow solid, yield 86.5%, HPLC purity 97.25%. m.p. 66.6~67.9 ℃; UV-Vis (EtOH) λ_max (log[ε/ (L•mol^－1•cm^－1)]): 270.5 (3.68), 218.5 (4.27) nm; ¹H NMR (600 MHz, CDCl₃) δ: 8.34 (t, J＝3.3 Hz, 1H, C²⁰-H), 7.70 (dd, J＝8.0, 2.6 Hz, 1H, C²¹-H), 7.22 (dd, J＝8.1, 4.8 Hz, 1H, C¹⁹-H), 4.35 (s, 2H, C¹⁵-H), 3.33 (s, 3H, N-CH₃), 2.65~2.57 (m, 2H, C⁶-H), 1.40~1.30 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.24~1.16 (m, 1H, C¹⁰-H_b), 1.07 (s, 3H, C¹³-H or C¹⁴-H), 0.98 (s, 3H, C¹³-H or C¹⁴-H), 0.91 (t, J＝7.2 Hz, 3H, C¹²-H)., 0.83 (dt, J＝8.9, 6.8 Hz, 1H, C⁷-H), 0.60 (td, J＝8.6, 5.4 Hz, 1H, C⁹-H); ¹³C NMR (150 MHz, CDCl₃) δ: 156.8 (C⁵), 150.6, 149.9, 148.7 (C³), 139.6, 132.3, 124.0, 34.0, 30.0, 28.9 (N-CH₃), 26.4, 23.1, 22.9, 20.9, 17.5, 14.8 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3051 (w, ＝CH), 2959 (s), 2935 (s), 2866 (m), 1566 (w, C＝C), 1465 (s, C＝N), 1388 (w), 681 (w, C—S—C) cm^－1; ESI-MS m/z: 364.99 [M+H]⁺. Anal. calcd for C₁₈H₂₅ClN₄S: C 59.24, H 6.91, N 15.35; found C 59.21, H 6.93, N 15.38.

  3-(((5-Chlorothiophen-2-yl)methyl)thio)-5-((2, 2-dime-thyl-3-propylcyclopropyl)methyl)-4-methyl-4H-1, 2, 4-tria-zole (6t): Yellow syrup, yield 85.8%, HPLC purity 98.12%. UV-Vis (EtOH) λ_max (log[ε/(L•mol^－1•cm^－1)]): 247.5 (4.02) nm; ¹H NMR (600 MHz, CDCl₃) δ: 6.66 (d, J＝1.6 Hz, 2H, C¹⁹-H, C²⁰-H), 4.45 (s, 2H, C¹⁵-H), 3.35 (s, 3H, N-CH₃), 2.68~2.59 (m, 2H, C⁶-H), 1.41~1.32 (m, 3H, C¹¹-H and C¹⁰-H_a), 1.25~1.19 (m, 1H, C¹⁰-H_b), 1.08 (s, 3H, C⁸-CH₃), 0.99 (s, 3H, C⁸-CH₃), 0.92 (t, J＝7.2 Hz, 3H, C¹²-H), 0.85 (dt, J＝8.9, 6.9 Hz, 1H, C⁷-H), 0.61 (td, J＝8.6, 5.5 Hz, 1H, C⁹-H); ¹³C NMR (151 MHz, CDCl₃) δ: 156.8 (C⁵), 148.9 (C³⁾, 138.4, 129.9, 126.7, 125.8, 33.5, 30.0, 29.0 (NCH₃), 26.5, 23.1, 23.0, 21.0, 17.5, 14.9 (C¹³, C¹⁴), 14.1; IR (KBr) ν: 3057 (w, ＝CH), 2962 (s), 2929 (s), 2869 (s), 1480 (s, C＝N), 1456 (s), 1379 (w), 684 (w, C—S—C) cm^－1; ESI-MS m/z: 369.97 [M+H]⁺. Anal. calcd for C₁₇H₂₄ClN₃S₂: C 55.19, H 6.54, N 11.36; found C 55.23, H 6.52, N 11.35.

  3.6   Antifungal activity test

  In this work, the agar dilution method was applied to test the in vitro antifungal activity. The test of inhibitory rates of compounds 6a~6t against the tested fungi was performed according to the literature.^[41] At (24±1) ℃, the culture flat containing 50 μg/mL tested compound emulsion was cultured for 48 h. The expanded diameter of fungus tray was measured. The emulsion containing solvent and surfactant without the tested compounds was used as the blank control. There were three replicates for each tested compound. Compared with the blank assay, the relative inhibition percentage was calculated. Activity grading indicators: Grade A: ≥90%; Grade B: 70%~90%; Grade C: 50~70%; Grade D: < 50%.

  3.7   Herbicidal activity test

  3.7.1   Inhibition of the root-growth of Rape (B. cam- pestris)

  The test of inhibitory rate of compounds 6a~6t against the root-growth of rape (B. campestris) was performed by the reported method.^[41] Under the support of emulsifying agent TW-80, the tested compound was modulated into the emulsion with concentration of 10 or 100 μg/mL. Then, 2 mL of emulsion was added to a 6 cm Petri dish placed with 15 seeds on a 5.6 cm filter paper. After cultivation 72 h in darkness at (28±1) ℃, the radicle lengths of seedlings were measured. The emulsion containing solvent and surfactant without the tested compounds were used as the blank control. All experiments were required to be repeated three times. The relative inhibition percentage was calculated by comparing with the control. Activity grading indicators: Grade A: ≥80%; Grade B: 60%~79%; Grade C: 40%~59%; Grade D: ≤39%.

  3.7.2   Inhibition of the seedling growth of barnyard grass (E. crusgalli)

  The test of inhibitory rate of compounds 6a~6t against the seedling-growth of barnyard grass (E. crusgalli) was performed according to the reported method.^[41] Supported by TW-80, the tested compound was modulated into 10 or 100 μg/mL emulsion. Then, 6 mL of emulsion was added to a 50 mL beaker placed with 15 germinated seeds on a filter paper. After cultivation 72 h under light irradiation (3000 Lux) at (28±1) ℃, the heights of seedlings were measured. The emulsion containing solvent and surfactant without the tested compounds were used as the blank control. All experiments were required to be repeated three times. The relative inhibition percentage was calculated by comparing with the control. Activity grading indicators: Grade A: ≥80%; Grade B: 60%~79%; Grade C: 40%~59%; Grade D: ≤39%.

  4.   Conclusion

  Twenty novel 4-methyl-1, 2, 4-triazole-thioethers containing gem-dimethylcyclopropane ring were designed, synthesized, characterized, and evaluated for their antifungal and herbicidal activities by using the natural product 3-carene as starting material. The bioassay result revealed that, at 50 μg/mL, compounds 6a, 6e, 6q and 6l exhibited excellent antifungal activities of 84.1%~95.5% against P. piricola, showing much better antifungal activity than that of the commercial fungicide chlorothalonil. And compounds 6q, 6p, 6k and 6d displayed excellent herbicidal activities of 81.9%~88.0% against the root-growth of rape (B. campestris), showing much better herbicidal activity than that of the commercial herbicide flumioxazin at 100 μg/mL. Compounds 6a, 6e, and 6q were leading compounds worthy of further investigation. In order to design more effective antifungal compounds against P. piricola, the 3D-QSAR analysis was carried out using the CoMFA method. A reasonable and effective 3D-QSAR model (r²＝0.985, q²＝0.509) had been established, and a new molecule with modification on phenyl groups were designed.

  Supporting Information ¹H NMR, ¹³C NMR, FTIR, ESI-MS and UV-Vis for the synthesized compounds. The Supporting Information is available free of charge via the Internet at http://sioc-journal.cn.

  
  
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• 

  Scheme 1  Synthesis of 4-methyl-1, 2, 4-triazole-thioethers 6a~6t containing gem-dimethylcyclopropane ring

  下载: 全尺寸图片 幻灯片
  

  Figure 1  Predicted ED value of CoMFA model vs experimental ED value

  下载: 全尺寸图片 幻灯片
  

  Figure 2  Contours of steric contribution (a) and electrostatic contribution (b)

  下载: 全尺寸图片 幻灯片
  

  Figure 3  Newly designed molecule of 3-(((5-((2, 2-dimethyl-3- propylcyclopropyl)methyl)-4-methyl-4H-1, 2, 4-triazol-3-yl)thio)-methyl)-N, N-bis(2-methylpentan-2-yl)aniline

  下载: 全尺寸图片 幻灯片
  

  Figure 4  Asterisk skeleton of title compounds

  下载: 全尺寸图片 幻灯片
  

  Figure 5  Superposition modes of compounds

  下载: 全尺寸图片 幻灯片

  Table 1.  Antifungal activities of the target compounds 6a~6t at 50 μg/mL^a

  Compd.	Inhibition rate/%
  	F. oxysporum f. sp. Cucumerinum	C. arachidicola	P. piricola	A. solani	G. zeae	R. solani	B. myadis	C. orbicalare
  Chlorothalonil	100	73.3	75.0	73.9	73.1	96.1	90.4	91.3
  5	24.0	43.8	55.0	42.1	30.0	51.9	33.3	42.9
  6a	37.1	39.1	95.5	42.9	41.4	77.5	47.2	55.6
  6b	45.7	39.1	52.3	50.0	44.8	70.4	52.8	47.2
  6c	28.6	43.5	79.5	46.4	37.9	57.7	41.7	50.0
  6d	37.1	30.4	75.0	42.9	51.7	70.4	52.8	50.0
  6e	37.1	65.2	90.9	57.1	44.8	74.6	61.1	52.8
  6f	42.9	26.1	77.3	42.9	58.6	71.8	47.2	55.6
  6g	25.7	52.2	59.1	42.9	44.8	70.4	30.6	30.6
  6h	31.4	30.4	75.0	42.9	44.8	70.4	55.6	38.9
  6i	40.0	26.1	68.2	35.7	44.8	69.0	44.4	55.6
  6j	25.7	26.1	77.3	35.7	41.4	69.0	27.8	30.6
  6k	48.6	52.2	75.0	50.0	62.1	66.2	50.0	58.3
  6l	25.7	21.7	84.1	39.3	37.9	70.4	52.8	50.0
  6m	40.0	65.2	40.9	50.0	37.9	62.0	52.8	50.0
  6n	62.9	69.6	75.0	60.7	44.8	70.4	66.7	61.1
  6o	34.3	65.2	56.8	57.1	55.2	66.2	36.1	41.7
  6p	37.1	21.7	52.3	42.9	58.6	69.0	36.1	52.8
  6q	40.0	73.9	86.4	60.7	44.8	54.9	47.2	41.7
  6r	25.7	47.8	52.3	50.0	51.7	38.0	33.3	41.7
  6s	22.9	30.4	75.0	35.7	24.1	47.9	30.6	33.3
  6t	42.9	21.7	68.2	35.7	37.9	70.4	27.8	44.4
  a Chlorothalonil, a current commercial fungicide, was used as a positive control. Values are the average of three replicates.

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  Table 2.  Growth inhibition rate (%) of the target compounds 6a~6t at 10 and 100 μg/mL^a

  Compd.	B. campestris			E. crusgalli
  	10 mg/L	100 mg/L		10 mg/L	100 mg/L
  Flumioxazin	57.8	63.0		95.1	97.5
  5	63.8	72.5		0	20
  6a	39.8	79.4		0	22.9
  6b	14.2	70.4		0	0
  6c	18.2	74.2		0.9	4.6
  6d	30.2	81.9		0	11.9
  6e	15.7	78.9		6.4	19.3
  6f	20.2	69.4		0	0
  6g	18.2	72.1		3.4	17.4
  6h	7.6	72.9		4.6	6.4
  6i	0	54.1		0	0
  6j	10.2	78.9		0	0
  6k	22.2	83.9		0	14.4
  6l	19.2	69.4		0.9	4.6
  6m	7.6	63.9		0.9	2.8
  6n	47.3	77.9		0	26.6
  6o	0	63.9		14.4	31.5
  6p	53.1	86.7		11.9	33.9
  6q	43.3	88		0	0
  6r	29	77.4		0	0.9
  6s	13.2	76.7		0.9	8.2
  6t	25.2	63.4		0	0
  a Flumioxazin, a current commercial herbicide was used as a positive control.

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  Table 3.  Summary of CoMFA analysis

  q2	r2	S	N	F	Contribution/%
  					Steric	Electrostatic
  0.509	0.985	0.061	6	89.985	74.6	25.4

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  Table 4.  ED values of experimental and predicted activities^a

  Compd.	ED	ED''	Residue
  6a	－1.19	－1.28	0.09
  6b	－2.50	－2.43	－0.07
  6c	－1.95	－1.98	0.03
  6d	－2.06	－2.04	－0.02
  6e	－1.56	－1.49	－0.07
  6f	－2.03	－2.05	0.02
  6g	－2.40	－2.36	－0.04
  6h	－2.06	－2.04	－0.02
  6i	－2.28	－2.30	0.02
  6j	－2.04	－2.08	0.04
  6k	－2.08	－2.06	－0.02
  6l	－1.83	－1.80	－0.03
  6m	－2.76	－2.82	0.06
  6n	－2.09	－2.06	－0.03
  6o	－2.43	－2.46	0.03
  a ED＝experimental value, ED''＝predictive value of ED.

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