Known triazole fungicides – a new trick

Abstract

Tebuconazole and propiconazole were converted into salts by reaction with inorganic and organic acids. Numerous novel salts were obtained as a result, many of which could be characterized as protic ionic liquids. Their thermal stability and biological activity against fungal species Fusarium culmorum, Microdochium nivale, Sclerotinia sclerotiorum and Botrytis cinerea (in concentration range from 10 up to 1000 ppm) were assessed in the framework of this study. The evaluation revealed that high antifungal activity of the synthesized tebuconazole- and propiconazole-based salts, which may be classified as new triazole fungicides, was preserved. Physical properties of the obtained salts have changed significantly, thus creating new application possibilities of known triazole fungicides.

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Introduction

Tebuconazole – (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol and propiconazole – (±)-1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole represent the group of popular triazole fungicides used in agriculture to treat pathogenic plant fungi. Triazoles were introduced in the 1970s and soon became the dominant group of fungicides. Despite this, the resistance of pathogenic fungi to these substances develops relatively slowly.¹ According to the World Health Organization toxicity classification, tebuconazole is listed as Class III (slightly hazardous) and propiconazole as Class II (moderately toxic).² Both of these fungicides belong to a class of inhibitors of sterol 14α-demethylation and they are widely used as foliar applications on cereals, fruits, vegetable, tea plants, ornamentals and as seed treatments.³ Tebuconazole and propiconazole have a single site mode of action and they are components of many different products dedicated to agriculture and plant disease control. These fungicides exhibit systemic action and they are able to move via the xylem to different plant tissues, even those which were not directly treated with the compound.⁴ High activity towards species such as Botrytis cinerea, Sclerotinia sclerotiorum, Alternaria spp. and Leptosphaeria spp. makes these triazoles very effective at low doses.

Tebuconazole is a white crystalline powder with water solubility equal to 0.032 g L⁻¹ at 20 °C and propiconazole is a yellowish oil with water solubility equal to 0.099 g L⁻¹ at 20 °C. Commercial formulas of tebuconazole and propiconazole require the formation of emulsion in water, which can limit some potential applications. Aside from their high biological activity, tebuconazole and propiconazole have been successfully used in extraction of metals^5,6 and acids,⁷ however structures of the latter have not been well described.

Ionic liquids (ILs) are a very attractive group of compounds. Variety of structures and unique properties thereof contribute to numerous uses in many different fields. Since ILs are characterized by low melting points and negligible volatility, they have found use as green solvents, non-toxic and easy to recycle.^8–13 Chemicals converted to ILs exhibit improved properties, making their use easier and more effective.¹⁴ They are efficient food deterrents,¹⁵ herbicides^14,16–18 and herbicide-plant regulators.^19,20 There are some examples of fungicidal ILs described in literature,^21–25 hence this manuscript is focused on presenting a new, cheap and efficient method, which may be used to obtain ILs by modifying the existing structures of commonly used fungicides.

Results and discussion

Tebuconazole- and propiconazole-based salts were synthesized in one step reaction with organic or inorganic acids (Fig. 1).

Fig. 1 Synthesis of tebuconazole and propiconazole based salts.

The acids used for the synthesis were characterized by various pK_a values (from −7 for hydrochloric acid, to +3.86 for D,L-lactic acid). Reactions were conducted at room temperature with high yields (exceeding 90%). The progress of each reaction was monitored by changes in pH value of acids solutions in methanol. In case of all of obtained salts, the equilibrium state was reached after 15 to 45 minutes from adding tebuconazole or propiconazole, depending on the pK_a value of the acid. For strong acids, with a pK_a value ≤2, the reaction time was approx. 15–20 minutes, while for acids, with a pK_a value >2, the reaction time was extended to 40–45 minutes. The synthesized salts were dried under vacuum (10 mbar) at 45 °C for 10 h and stored over P₄O₁₀. The water contents of the dried salts were measured by Karl-Fischer method and found to be less than 500 ppm. The obtained salts were stable in air and in contact with water or the tested organic solvents. They were insoluble in hexane and water but soluble in acetone, dichloromethane, DMSO and low molecular weight alcohols (methanol, 2-propanol).

The synthesized salts (hydrochlorides, dihydrogen citrates, dodecylbenzenesulfonates, methanesulfonates, p-toluenesulfonate, benzenesulfonates, oxalate, tetrafluoroborate, methoxyacetates, L-tartrate, nitrates, dihydrogen phosphate, maleates, D,L-lactates, itaconate, malate, hydrogen sulfate, 4-methylbenzenesulfonates), the corresponding reaction yields and melting points were presented in Table 1.

Table 1 Prepared tebuconazole (1–16) and propiconazole (17–27) based salts

Salt	Anion	Yield [%]	Mp [°C]
a Lit. 126–128 °C.^7b Lit. 133.5 °C.^26
1	Hydrochloride – [Cl]	92	192–194^a
2	Dihydrogen citrate	99	Liquid
3	Dodecylbenzenesulfonate	98	Wax
4	Methanesulfonate	98	150–152
5	4-Methylbenzenesulfonate	92	172–174
6	Benzenesulfonate	93	137–139
7	Oxalate	98	80–83
8	Tetrafluoroborate – [BF4]	99	121–123
9	Methoxyacetate	92	Liquid
10	L-Tartrate	99	Wax
11	Nitrate – [NO3]	96	180–182
12	Dihydrogen phosphate – [H2PO4]	98	112–116
13	Maleate	98	120–123
14	D,L-Lactate	97	Liquid
15	Itaconate	98	86–90
16	Malate	98	87–90
17	Nitrate – [NO3]	99	113–115^b
18	Hydrochloride – [Cl]	97	102–104
19	Hydrogen sulfate – [HSO4]	99	Liquid
20	4-Methylbenzenesulfonate	96	Wax
21	Dodecylbenzenesulfonate	98	Liquid
22	Methanesulfonate	99	Wax
23	Benzenesulfonate	99	Wax
24	Dihydrogen citrate	99	Liquid
25	Methoxyacetate	92	Liquid
26	D,L-Lactate	97	Liquid
27	Maleate	98	Liquid

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Among the obtained tebuconazole-based salts (1–16), two of them (1, 3) have been previously reported in literature.^7,26 The synthesized salts were crystalline solids with narrow range of melting points (1, 4–8, 11–13, 15–16), waxes (3, 10) or liquids (2, 9, 14). 8 out of the total 16 obtained salts can be described as protic ILs (melting points < 100 °C). Propiconazole-based salts 17 and 18 were obtained as crystalline solids, 20, 22, 23 were waxes and the remaining salts were liquids. Salts 19–27 can be described as protic ILs. Propiconazole nitrate (17) has been previously described in literature as a solid with a melting point of 133.5 °C. The difference between the melting point values can be caused by using pure nitric acid instead of a mixture of nitric acid with acetic acid.³

The synthesized salts were thermally stable, as confirmed by the data presented in Table 2.

Table 2 Thermal transitions and decomposition temperatures of prepared salts

Salt	Tg^a	Tc^b	Tm^c	Tonset 5%^d	Tonset 50%^d
a Glass transition temperature in °C.b Crystallization temperature in °C.c Melting point on heating in °C.d Decomposition temperatures as Tonset 5% to 5 wt% and Tonset 50% to 50 wt% mass loss, first and second decomposition in °C.
1	5	—	191	189	196/320
2	21	—	—	168	195/340
3	8	—	83	251	322
4	—	141	153	170	308/465
5	—	—	174	242	295
6	39	127	144	252	322
7	−0.4	—	81	163	189/320
9	−1.4	—	—	167	175/340
10	24	—	—	192	208/314
11	—	—	182	182	185/260
12	59	—	115	243	304
13	15	—	130	152	308
14	−3.6	—	—	176	238/315
15	4.3	—	81	182	215/360
16	8.9	—	93	198	333
17	−18	—	114	150	155/328
18	−21	48	100	146	148/328
19	−11	—	—	183	284
20	26	—	—	266	323
21	−4.5	—	—	262	328
22	13	—	—	219	318
23	12	—	—	262	339
24	12	—	—	168	190/320
25	−30	—	—	166	188/336
26	−23	—	—	171	180/300

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The glass transition temperature values ranged from −30 to 59 °C (except for 4, 5, 11). The glass transition temperature for propiconazole was at −24 °C, whereas for tebuconazole the value had not occurred.

Highest thermal stability among tebuconazole-based salts was observed for benzenesulfonate (6) with the T_{onset 5%} value at 252 °C and T_{onset 50%} value at 322 °C. For sulfonates (3–6), the thermal stability order may be established as following: methanesulfonate < p-toluenesulfonate < dodecylbenzenesulfonate < benzenesulfonate. Additionally, an exothermal effect was observed (270 J g⁻¹) for methanesulfonate (4) during its decomposition. For nitrate (11), the melting point reached the same value as the decomposition temperature (182 °C). In general, two steps of thermal decomposition were observed for most of tebuconazole-based salts. The highest thermal stability among propiconazole-based salts was observed for 4-methylbenzenesulfonate (20) with the T_{onset 5%} value at 266 °C and T_{onset 50%} value at 322 °C. An exothermal decomposition (115 J g⁻¹) was observed for nitrate (17). Two steps of thermal decomposition were observed for propiconazole-based salts 17, 18, 24–26. In case of sulfonates (20–23) only hydrogensulfonate (20) exhibited two steps of thermal decomposition.

Decomposition temperatures for tebuconazole amounted to 302 °C for T_{onset 5%} and 364 °C for T_{onset 50%}, while those for propiconazole amounted to 265 °C for T_{onset 5%} and 322 °C for T_{onset 50%}, with marked differences from values established for synthesized salts 1–26.

Viscosities of the prepared salts were determined for protic ILs 21, 25 and 26. The measured values ranged from 0.805 Pa s (for 25, at 20 °C) to 45.781 Pa s (for 21, at 25 °C, the test was impossible to conduct at lower temperature). Viscosity values strongly depended on temperature. The largest change was noted for 21, with a decrease of viscosity value to 0.111 Pa s at 80 °C, as shown in Fig. 2.

Fig. 2 Viscosity of protic ILs: ▲ – 21, ■ – 25, ● – 26.

Determination of density values for the obtained ILs was challenging due to their high viscosity. The values measured for 25 and 26 amounted to 1.2741 and 1.2777 g mL⁻¹ at 20 °C, respectively, and decreased in sequence with increasing temperature to 40 °C (1.2557 and 1.2596 g mL⁻¹), 60 °C (1.2370 and 1.2410 g mL⁻¹) and 80 °C (1.2178 and 1.2217 g mL⁻¹).

Results presented in the Table 3 show that the tested tebuconazole-based salts 5 and 6 were active against B. cinerea, F. culmorum and M. nivale.

Table 3 Inhibition of the growth of Botrytis cinerea, Fusarium culmorum and Microdochium nivale due to tebuconazole based salts

Object	The growth of B. cinerea mycelium [cm]			The growth of F. culmorum mycelium [cm]			The growth of M. nivale mycelium [cm]
	10 [ppm]	100 [ppm]	1000 [ppm]	10 [ppm]	100 [ppm]	1000 [ppm]	10 [ppm]	100 [ppm]	1000 [ppm]
a Commercial fungicide containing tebuconazole.
Control	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6
5	0.0	0.0	0.0	0.1	0.0	0.0	0.3	0.0	0.0
6	1.0	0.0	0.0	1.5	0.0	0.0	2.9	0.0	0.0
Tebu 250 EW^a	0.0	0.0	0.0	0.8	0.0	0.0	1.2	0.0	0.0
LSD(P=0.05)	0.29	0.15	0.08	0.10	0.17	—	0.27	0.15	0.14

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Significant differences between the inhibition of fungal growth for control and the tested salts were observed in all cases. Complete inhibition of mycelium growth was observed at concentrations of 100 and 1000 ppm. Slight mycelial growth of F. culmorum and M. nivale was noticed when the tested salts 5 and 6 were used at a concentration of 10 ppm, while growth of B. cinerea was observed in the presence of 10 ppm of benzenesulfonate (6).

Salts 10, 12–16, 20, 25–27 at a concentration of 100 and 1000 ppm completely inhibited the growth of S. sclerotiorum, F. culmorum and M. nivale, as shown in Table 4.

Table 4 Inhibition of the growth of Sclerotinia sclerotiorum, Fusarium culmorum and Microdochium nivale due to tebuconazole and propiconazole based salts

Object	The growth of S. sclerotiorum mycelium [cm]			The growth of F. culmorum mycelium [cm]			The growth of M. nivale mycelium [cm]
	10 [ppm]	100 [ppm]	1000 [ppm]	10 [ppm]	100 [ppm]	1000 [ppm]	10 [ppm]	100 [ppm]	1000 [ppm]
a Commercial fungicide containing tebuconazole.b Commercial fungicide containing propiconazole.
Control	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6
10	3.7	0.0	0.0	1.3	0.0	0.0	2.3	0.0	0.0
12	4.6	0.0	0.0	4.6	0.0	0.0	3.4	0.0	0.0
13	2.5	0.0	0.0	0.5	0.0	0.0	1.3	0.0	0.0
14	2.1	0.0	0.0	0.4	0.0	0.0	1.3	0.0	0.0
15	4.2	0.0	0.0	2.2	0.0	0.0	2.7	0.0	0.0
16	0.1	0.0	0.0	0.0	0.0	0.0	0.4	0.0	0.0
20	1.8	0.0	0.0	0.5	0.0	0.0	0.4	0.0	0.0
25	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
26	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
27	2.1	0.0	0.0	0.5	0.0	0.0	0.0	0.0	0.0
Tebu 250 EW^a	4.6	0.0	0.0	0.5	0.0	0.0	2.4	0.0	0.0
Bumper 250 EC^b	0.6	0.0	0.0	0.2	0.0	0.0	0.0	0.0	0.0
LSD(P=0.05)	0.21	—	—	0.16	—	—	0.47	—	—

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At the concentration of 10 ppm the activity of the tested salts varied depending on both the salt and the fungus. Salts 25 and 26 completely inhibited the growth of all fungi, maleate (27) and Bumper 250 EC inhibited only M. nivale, while malate (16) caused total inhibition of growth for F. culmorum. On the other hand dihydrogen phosphate (12) and itaconate (15) did not exhibit activity against S. sclerotiorum, F. culmorum and M. nivale. After application of other salts at a concentration of 10 ppm a differentiated growth of fungi was observed. The results presented in the Table 5 show that the tested salts 17–19, 21, 23 and 24 as well as commercial products Tebu 250 EW and Bumper 250 EC completely inhibited the growth of B. cinerea, F. culmorum and M. nivale at a concentration of 100 and 1000 ppm. At the concentration of 10 ppm the growth of all the tested fungi was completely inhibited by salts 19 and 21 as well as Bumper 250 EC.

Table 5 Inhibition of the growth of Botrytis cinerea, Fusarium culmorum and Microdochium nivale due to propiconazole based salts

Object	The growth of B. cinerea mycelium [cm]			The growth of F. culmorum mycelium [cm]			The growth of M. nivale mycelium [cm]
	10 [ppm]	100 [ppm]	1000 [ppm]	10 [ppm]	100 [ppm]	1000 [ppm]	10 [ppm]	100 [ppm]	1000 [ppm]
a Commercial fungicide containing tebuconazole.b Commercial fungicide containing propiconazole.
Control	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6
17	0.0	0.0	0.0	0.1	0.0	0.0	0.2	0.0	0.0
18	0.0	0.0	0.0	0.1	0.0	0.0	1.1	0.0	0.0
19	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
21	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
23	0.0	0.0	0.0	0.1	0.0	0.0	0.0	0.0	0.0
24	0.0	0.0	0.0	0.1	0.0	0.0	0.0	0.0	0.0
Tebu 250 EW^a	0.0	0.0	0.0	0.1	0.0	0.0	1.2	0.0	0.0
Bumper 250 EC^b	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
LSD(P=0.05)	0.28	0.28	0.28	0.09	0.08	0.07	0.19	0.16	0.16

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The ionic liquids 23 and 24 caused a complete inhibition of growth for B. cinerea and M. nivale, whereas ionic liquids 17 and 18 inhibited only B. cinerea.

The obtained results indicate that the synthesized tebuconazole- and propiconazole-based salts preserved high activity towards fungi, which is a characteristic trait of the precursor compounds. The cation created by the addition of a proton to the nitrogen atom is responsible for the fungicidal activity. It was previously established, that a substituent in the tebuconazole cation, which is bigger than a proton (i.e. methyl, benzyl or alkyl), contributes to a decrease of the fungicidal activity.²⁷ The obtained propiconazole-based salts were more effective compared to the tebuconazole-based salts. In the case of the latter an influence of the anion on the biological activity was observed. The dihydrogen phosphate and itaconate anions seem to decrease the efficiency of the synthesized salts.

Overall, novel protic ILs exhibiting strong fungicidal properties were obtained. The proposed method for designing new, third generation ILs^28,29 was found to be efficient. This potentially opens up new possibilities of employing the commonly used active compounds in a modified form.

Conclusions

Synthesis of tebuconazole- and propiconazole-based salts was conducted with use of both organic and inorganic acids. New salts were obtained with high yields. Chemical modification of the triazole structure resulted in changed psychical properties. 17 of synthesized salts can be described as protic ILs. The obtained tebuconazole- and propiconazole-based salts are active against fungal species of Fusarium culmorum, Microdochium nivale, Sclerotinia sclerotiorum and Botrytis cinerea at a level equivalent to known triazole fungicides. The method presented in this study can be used to improve the physical properties of triazole fungicides and make their use easier and more efficient. The synthesized triazolium ILs do not exhibit a tendency to complex metals and their biodegradability will also change compared to the precursor compound.³⁰

Experimental

Materials

Tebuconazole and propiconazole (both technical grade) were used without further purification. Hydrochloric acid (37%), citric acid (99%), 4-dodecylbenzenesulfonic acid (≥95%), methanesulfonic acid (≥99.5%), 4-methylbenzenesulfonate acid monohydrate (≥98.5%), benzenesulfonic acid (90%), oxalic acid (98%), tetrafluoroboric acid (48% in water), sulfuric acid (95–98%), methoxyacetic acid (98%), lactic acid (85%), L-tartaric acid (≥99%), nitric acid (70%), phosphoric acid (85% in water), maleic acid (≥99%) as well as malic acid (≥98%) were purchased from Sigma Aldrich and Fluka, and used as received.

Synthesis

The corresponding acid was first dissolved in methanol, then a stoichiometric amount of tebuconazole or propiconazole was added. The reaction was performed at room temperature, until equilibrium was reached. The progress of the reaction and the equilibrium states of the reactions were determined by changes in observed pH values for reaction mixtures. Upon evaporation of the solvent, the product was washed with water and hexane. Finally, the obtained salts were dried under vacuum (10 mbar) at 45 °C for 10 h.

Analysis

¹H NMR spectra were recorded on a Mercury Gemini 300 spectrometer operating at 300 MHz with TMS as the internal standard. ¹³C NMR spectra were obtained with the same instrument at 75 MHz (the spectra are available in ESI†). CHN elemental analyses were performed at the Adam Mickiewicz University, Poznan (Poland). The water content was determined by using an Aquastar volumetric Karl Fischer titration with Composite 5 solution as the titrant and anhydrous methanol as a solvent. Melting point values were obtained by visual observation via hot-plate apparatus. Densities measurements were carried using an Automatic Density Meter DDM2911 with a mechanical oscillator method. The densities of the samples (about 2.0 mL) were measured with respect to temperature controlled conditions via Peltier, at 25 °C. Viscosity measurements were performed using a rheometer (Rheotec RC30-CPS) with cone-shaped geometry (C50-2). The viscosities of the samples (about 1.5 mL) were measured with respect to temperature, from 20 to 90 °C. Determination of refractive index values was carried out using Automatic Refractometer J357 with electronic temperature control.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol chloride (1). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.63 (m, 1H); 1.79 (m, 1H); 2.05 (m, 1H); 2.54 (s, 1H); 2.63 (m, 1H); 4.51 (d, J = 2.2 Hz, 2H); 7.19 (d, J = 8.3 Hz, 2H); 7.31 (d, J = 8.4, 2H); 8.81 (s, 1H); 9.64 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.60; 29.53; 36.39; 38.09; 54.82; 75.15; 128.22; 130.08; 130.24; 141.80; 143.77; 145.67.

Elemental analysis calc. (%) for C₁₆H₂₃Cl₂N₃O (344.28): C 55.82; H 6.78; N 12.21. Found: C 56.12; H 6.40; N 12.51.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol dihydrogen citrate (2). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.64 (m, 1H); 1.80 (m, 1H); 1.91 (m, 1H); 2.55 (m, 2H); 2.72 (m, 4H) 4.47 (d, J = 2.2 Hz, 2H); 7.16 (d, J = 8.2 Hz, 2H); 7.28 (m, 2H); 8.03 (s, 1H); 8.53 (s, 1H); 12.5 (m, 2H). ¹³C NMR (DMSO-d₆) δ (ppm): 25.60; 29.52; 36.39; 54.82; 75.14; 128.22; 130.07; 141.79; 143.76; 145.66.

Elemental analysis calc. (%) for C₂₂H₃₀ClN₃O₈ (499.94): C 52.85, H 6.05, N 8.40. Found: C 53.47; H 6.42; N 8.79.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol 4-dodecylbenzenesulfonate (3). ¹H NMR (DMSO-d₆) δ (ppm) 0.81 (m, 3H); 0.95 (s, 9H); 1.06 (m, 16H); 1.19 (m, 3H); 1.64 (m, 2H); 1.80 (m, 2H); 2.00 (m, 2H); 2.41 (t, J = 3.6 Hz, 1H); 2.64 (m, 2H); 4.53 (d, J = 2.2 Hz, 2H); 7.10 (d, J = 8.9 Hz, 2H); 7.17 (d, J = 12.3 Hz, 2H); 7.29 (d, J = 8.2 Hz, 2H); 7.53 (d, J = 8.5 Hz, 2H); 8.73 (s, 1H); 9.42 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm): 13.91; 22.09; 22.26; 25.51; 29.12; 29.52; 31.29; 36.4; 54.67; 75.1; 125.56; 128.19; 130.04; 141.72; 143.99; 146.05.

Elemental analysis calc. (%) for C₃₄H₅₂ClN₃O₄S (634.31): C 64.38, H 8.26, N 6.62. Found: C 63.99; H 8.57; N 6.24.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol methanesulfonate (4). ¹H NMR (DMSO-d₆) δ (ppm) 0.96 (s, 9H); 1.60 (m, 1H); 1.79 (m, 1H); 2.08 (m, 1H); 2.49 (s, 3H); 2.58 (m, 2H); 4.48 (m, 2H); 7.18 (m, 2H); 7.30 (m, 2H); 8.69 (s, 1H); 9.36 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.53; 29.49; 36.36; 54.59; 75.14; 128.23; 130.06; 141.78; 144.10; 146.42.

Elemental analysis calc. (%) for C₁₇H₂₆ClN₃O₄S (403.92): C 50.55, H 6.49, N 10.40. Found: C 50.17; H 6.88; N 10.87.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol 4-methylbenzenesulfonate (5). ¹H NMR (DMSO-d₆) δ (ppm) 0.96 (s, 9H); 1.60 (m, 1H); 1.80 (m, 1H); 2.08 (m, 1H); 2.29 (s, 3H); 2.58 (m, 2H); 4.49 (m, 2H); 7.15 (m, 4H); 7.19 (m, 2H); 7.29 (m, 2H); 8.81 (s, 1H); 9.50 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 20.83; 25.55; 29.54; 36.43; 54.79; 75.11; 125.55; 128.71; 130.27; 138.20; 141.71; 143.88; 144.91; 145.69.

Elemental analysis calc. (%) for C₂₃H₃₀ClN₃O₄S (480.02): C 57.55, H 6.30, N 8.75. Found: C 57.17; H 5.98; N 8.41.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol benzenesulfonate (6). ¹H NMR (DMSO-d₆) δ (ppm) 0.96 (s, 9H); 1.60 (m, 1H); 1.80 (m, 1H); 2.12 (m, 1H); 2.59 (m, 2H); 4.49 (m, 2H); 7.17 (m, 2H); 7.32 (m, 5H); 7.66 (m, 2H); 8.83 (s, 1H); 9.53 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.55; 29.56; 36.45; 54.84; 75.10; 125.53; 127.82; 128.24; 128.80; 130.08; 130.29; 141.71; 143.84; 145.53; 147.69.

Elemental analysis calc. (%) for C₂₂H₂₈ClN₃O₄S (465.99): C 56.70, H 6.06, N 9.02. Found: C 56.33; H 6.34; N 8.78.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol oxalate (7). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.62 (m, 1H); 1.79 (m, 1H); 1.91 (m, 1H); 2.52 (s, 1H); 2.56 (m, 1H); 4.34 (m, 2H); 7.15 (d, J = 8.5 Hz, 2H); 7.30 (d, J = 8.5 Hz, 2H); 8.04 (s, 1H); 8.54 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.46; 29.28; 36.06; 37.98; 53.51; 75.41; 128.18; 130.04; 130.16; 142.05; 145.34; 150.66; 161.38.

Elemental analysis calc. (%) for C₁₈H₂₄ClN₃O₅ (397.85): C 54.34; H 6.08; N 10.56. Found: C 54.72; H 5.66; N 10.19.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol tetrafluoroborate (8). ¹H NMR (DMSO-d₆) δ (ppm) 0.96 (s, 9H); 1.62 (m, 1H); 1.82 (m, 1H); 2.06 (m, 1H); 2.51 (t, J = 3.6 Hz, 1H); 2.62 (m, 1H); 4.45 (m, 2H); 7.19 (d, J = 8.2 Hz, 2H); 7.29 (m, 2H); 8.55 (s, 1H); 9.17 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.51; 29.47; 36.34; 54.35; 75.21; 128.23; 130.17; 141.81; 144.32; 147.25. ¹⁹F NMR (DMSO-d₆) δ (ppm) 148.65.

Elemental analysis calc. (%) for C₁₆H₂₃BClF₄N₃O (395.63): C 48.57, H 5.86, N 10.62. Found: C 48.92; H 5.16; N 10.35.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol methoxyacetate (9). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.62 (m, 1H); 1.79 (m, 1H); 1.92 (m, 1H); 2.52 (s, 1H); 3.31 (s, 3H); 3.95 (s, 2H); 4.34 (m, 1H); 7.15 (d, J = 8.5 Hz, 2H); 7.30 (d, J = 8.5 Hz, 2H); 8.04 (s, 1H); 8.54 (s, 1H); 12.66 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.44; 29.27; 36.04; 37.96; 53.49; 58.27; 68.88; 75.40; 128.16; 130.02; 130.16; 142.04; 145.32; 150.66; 171.54.

Elemental analysis calc. (%) for C₁₉H₂₈ClN₃O₄ (383.87): C 56.32; H 6.83; 10.95. Found: C 55.94; H 7.20; N 10.57.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol L-tartrate (10). ¹H NMR (DMSO-d₆) δ (ppm) 0.94 (s, 9H); 1.63 (m, 1H); 1.80 (m, 1H); 1.92 (m, 1H); 2.53 (s, 1H); 2.57 (m, 1H); 4.37 (m, 2H); 4.38 (s, 2H); 7.15 (d, J = 8.4 Hz, 2H); 7.30 (d, J = 8.5 Hz, 2H); 8.05 (s, 1H); 8.55 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.46; 29.30; 36.07; 37.98; 53.55; 72.23; 75.44; 128.18; 130.03; 130.19; 142.03; 145.34; 150.64; 173.21.

Elemental analysis calc. (%) for C₂₂H₂₈ClN₃O₇ (457.91): C 54.37; H 6.64; N 8.65. Found: C 54.67; H 6.99; N 8.98.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol nitrate (11). ¹H NMR (DMSO-d₆) δ (ppm) 0.98 (s, 9H); 1.66 (m, 1H); 1.85 (m, 1H); 2.01 (m, 1H); 2.43 (t, J = 3.8 Hz, 1H); 2.62 (m, 1H); 4.50 (m, 2H); 7.20 (d, J = 8.4 Hz, 2H); 7.30 (m, 2H); 8.46 (s, 1H); 9.24 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.56; 29.49; 36.41; 54.29; 75.27; 128.26; 130.21; 141.61; 143.72; 146.89.

Elemental analysis calc. (%) for C₁₆H₂₃ClN₄O₄ (370.83): C 51.82, H 6.25, N 15.10. Found: C 52.11; H 6.89; N 15.39.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol dihydrogen phosphate (12). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.62 (m, 1H); 1.79 (m, 1H); 1.91 (m, 1H); 2.53 (s, 1H); 2.56 (m, 1H); 4.34 (m, 2H); 7.15 (d, J = 8.3 Hz, 2H); 7.30 (d, J = 8.4 Hz, 2H); 8.04 (s, 1H); 8.54 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.46; 29.27; 36.04; 37.98; 53.50; 75.41; 128.17; 130.04; 130.16; 142.05; 145.34; 150.66.

Elemental analysis calc. (%) for C₁₆H₂₅ClN₃O₅P (405.81): C 47.35; H 6.21; N 10.35. Found: C 47.69; H 5.85; N 10.70.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol maleate (13). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.61 (m, 1H); 1.79 (m, 1H); 1.92 (m, 1H); 2.52 (s, 1H); 2.56 (m, 1H); 4.34 (m, 2H); 6.30 (s, 2H), 7.15 (d, J = 8.5 Hz, 2H); 7.30 (d, J = 8.4 Hz, 2H); 8.05 (s, 1H); 8.55 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.48; 29.30; 36.08; 38.00; 53.55; 75.43; 128.21; 130.06; 130.19; 130.24; 142.06; 145.33; 150.58; 166.78.

Elemental analysis calc. (%) for C₂₀H₂₆ClN₃O₅ (423.89): C 56.67; 6.18; N 9.91. Found: C 56.30; H 6.79; N 10.26.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol D,L-lactate (14). ¹H NMR (DMSO-d₆) δ (ppm) 0.92 (s, 9H); 1.29 (m, 3H); 1.44 (m, 1H); 1.64 (m, 1H); 1.81 (m, 1H); 1.91 (m, 1H); 2.56 (m, 1H); 4.08 (m, 1H); 4.47 (d, J = 2.2 Hz, 2H); 7.16 (d, J = 8.2 Hz, 2H); 7.29 (m, 2H); 8.05 (s, 1H); 8.54 (s, 1H); 12.5 (m, 1H). ¹³C NMR (DMSO-d₆) δ (ppm): 25.60; 29.52; 36.39; 54.82; 75.14; 128.22; 130.07; 141.79; 143.76, 145.66.

Elemental analysis calc. (%) for C₁₉H₂₈ClN₃O₄ (397.90): C 56.67; H 6.18; N 9.91. Found: C 56.88; H 5.79; N 10.27.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol itaconate (15). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.62 (m, 1H); 1.79 (m, 1H); 1.92 (m, 1H); 2.52 (s, 1H); 2.56 (m, 1H); 3.24 (s, 2H); 4.34 (m, 2H); 5.72 (d, J = 1.5 Hz, 1H); 6.14 (d, J = 1.6 Hz, 1H); 7.15 (d, J = 8.5 Hz, 2H); 7.29 (d, J = 8.5 Hz, 2H); 8.04 (s, 1H); 8.53 (s, 1H); 12.48 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.49; 29.31; 36.09; 37.46; 38.01; 53.54; 75.46; 127.40; 128.22; 130.07; 130.21; 135.48; 142.07; 145.37; 150.69; 167.57; 172.05.

Elemental analysis calc. (%) for C₂₁H₂₈ClN₃O₅ (437.92): C 57.60; 6.44; 9.60. Found: C 57.00; H 6.06; N 9.27.

(RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-[(1H-1,2,4-triazol-4-ium)-1-ylmethyl]pentan-3-ol malate (16). ¹H NMR (DMSO-d₆) δ (ppm) 0.93 (s, 9H); 1.62 (m, 1H); 1.79 (m, 1H); 1.91 (m, 1H); 2.56 (m, 3H); 3.66 (m, 2H); 4.33 (m, 3H); 7.15 (d, J = 8.5 Hz, 2H); 7.29 (d, J = 8.5 Hz, 2H); 8.04 (s, 1H); 8.54 (s, 1H); 12.45 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 25.50; 29.33; 36.11; 38.02; 53.58; 67.09; 75.48; 128.23; 130.08; 130.23; 142.08; 145.38; 150.70; 171.92; 174.70.

Elemental analysis calc. (%) for C₂₀H₂₈ClN₃O₆ (441.91): C 54.36; H 6.39; N 9.51. Found: C 53.99; H 6.69; N 9.12.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium nitrate (17). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.30 (m, 4H); 3.27 (s, 1H); 3.91 (m, 3H); 4.85 (m, 2H); 7.44 (m, 2H); 7.66 (m, 1H); 8.41 (s, 1H); 9.14 (s, 1H); 11.86 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.81; 18.44; 34.35; 54.03; 69.64; 76.31; 77.51; 106.11; 127.26; 130.41; 132.48; 135.58; 144.65; 147.78.

Elemental analysis calc. (%) for C₁₅H₁₈Cl₂N₄O₅ (405.23): C 44.46; H 4.48; N 13.83. Found: C 44.83; H 4.62; N 13.53.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium chloride (18). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.20–1.40 (m, 4H); 3.29 (s, 1H); 3.91 (m, 2H); 4.84 (m, 2H); 7.40–7.47 (m, 2H); 7.67 (m, 1H); 8.39 (d, J = 12.4 Hz, 2H); 9.13 (d, J = 4.07 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.84; 18.40; 39.52; 69.56; 76.32; 77.47; 106.13; 127.33; 130.03; 130.63; 132.52; 134.54; 135.18; 144.58; 147.91.

Elemental analysis calc. (%) for C₁₅H₁₈Cl₃N₃O₂ (378.68): C 47.58; H 4.79; N 11.10. Found: C 47.22; H 5.10; N 11.36.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium hydrogen sulfate (19). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.30 (m, 4H); 3.30 (s, 1H); 3.92 (m, 2H); 4.88 (m, 2H); 7.43 (m, 2H); 7.67 (s, 1H); 8.60 (d, J = 15.1 Hz, 1H); 9.39 (d, J = 4.2 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.91; 18.44; 39.50; 69.66; 76.44; 77.67; 106.05; 127.35; 130.19; 130.74; 132.60; 134.74; 135.08; 144.39; 146.59.

Elemental analysis calc. (%) for C₁₅H₁₉Cl₂N₃O₆S (440.30): C 40.92; H 4.35; N 9.54. Found: C 40.51; H 4.01; N 9.88.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium 4-methylbenzenesulfonate (20). ¹H NMR (DMSO-d₆) δ (ppm) 0.85 (m, 3H); 1.28 (m, 4H); 2.30 (s, 3H); 3.27 (m, 1H); 3.89 (m, 2H); 4.84 (m, 2H); 7.17 (m, 2H); 7.45 (m, 4H); 7.67 (m, 1H); 8.48 (d, J = 16.6 Hz, 1H); 9.23 (d, J = 5.4 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.80; 18.34; 20.82; 34.14; 69.54; 76.30; 77.51; 106.03; 125.55; 127.34; 128.27; 130.05; 130.62; 132.50; 134.58; 135.07; 138.24; 144.86; 147.21.

Elemental analysis calc. (%) for C₂₂H₂₅Cl₂N₃O₅S (514.42): C 51.37; H 4.90; N 8.17. Found: C 51.71; H 4.53; N 7.85.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium dodecylbenzenesulfonate (21). ¹H NMR (DMSO-d₆) δ (ppm) 0.82 (m, 3H); 0.85 (m, 3H); 1.11 (m, 4H); 1.24 (m, 16H); 1.54 (m, 4H); 2.52 (m, 2H); 3.18 (m, 1H); 3.90 (m, 2H); 4.85 (m, 2H); 7.15 (m, 2H); 7.43 (m, 2H); 7.56 (m, 1H); 7.76 (m, 2H); 8.47 (d, J = 15.4 Hz, 1H); 9.27 (d, J = 3.3 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.93; 18.36; 22.09; 27.09; 29.05; 31.31; 34.14; 34.45; 36.33; 37.73; 69.55; 76.31; 77.52; 106.03; 125.58; 126.18; 126.80; 127.32; 130.06; 130.61; 132.51; 134.59; 135.05; 144.46; 145.11; 147.09.

Elemental analysis calc. (%) for C₃₃H₄₇Cl₂N₃O₅S (668.71): C 59.27; H 7.08; N 6.28. Found: C 59.66; H 7.29; N 6.00.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium methanesulfonate (22). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.29 (m, 4H); 2.54 (s, 3H); 3.29 (m, 1H); 3.91 (m, 2H); 4.86 (m, 2H); 7.48 (m, 2H); 8.46 (d, J = 21.7 Hz, 1H); 9.25 (d, J = 6.6 Hz, 1H); 10.90 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.89; 18.43; 34.22; 69.61; 76.37; 77.58; 106.08; 127.42; 130.11; 130.70; 132.57; 134.66; 135.11; 144.53; 147.12.

Elemental analysis calc. (%) for C₁₆H₂₁Cl₂N₃O₅S (438.33): C 43.94; H 4.61; N 9.61. Found: C 44.31; H 5.00; N 9.26.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium benzenesulfonate (23). ¹H NMR (DMSO-d₆) δ (ppm) 0.84 (m, 3H); 1.29 (m, 4H); 3.18 (m, 1H); 3.89 (m, 2H); 4.85 (m, 2H); 7.34 (m, 5H); 7.46 (m, 2H); 7.66 (m, 1H); 8.52 (d, J = 13.2 Hz, 1H); 9.26 (d, J = 7.1 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.83; 18.36; 34.17; 69.55; 76.31; 77.53; 106.01; 125.53; 127.38; 127.82; 128.80; 130.07; 130.66; 132.51; 134.61; 135.05; 144.45; 147.03.

Elemental analysis calc. (%) for C₂₁H₂₃Cl₂N₃O₅S (500.40): C 50.41; H 4.63; N 8.40. Found: C 50.06; H 7.02; N 8.07.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium dihydrogen citrate (24). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.31 (m, 4H); 2.69 (m, 5H); 3.24 (m, 1H); 3.61 (d, J = 19.6 Hz, 1H); 3.89 (m, 2H); 4.85 (m, 2H); 7.47 (m, 2H); 7.64 (m, 1H); 7.87 (d, J = 10.4 Hz, 1H); 8.43 (d, J = 1.9 Hz, 1H); 10.70 (s, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.93; 18.57; 34.32; 42.90; 53.51; 69.63; 72.57; 76.32; 77.48; 106.52; 127.27; 130.38; 132.51; 135.67; 145.49; 150.80; 171.33; 171.42; 174.88.

Elemental analysis calc. (%) for C₂₁H₂₅Cl₂N₃O₉ (534.34): C 49.63; H 5.11; N 7.89. Found: C 49.99; H 5.44; N 7.58.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium methoxyacetate (25). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.32 (m, 4H); 3.30 (m, 4H); 3.95 (m, 4H); 4.74 (m, 2H); 7.45 (m, 2H); 7.64 (s, 1H); 7.88 (d, J = 10.5 Hz, 1H); 8.42 (d, J = 1.9 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.79; 18.40; 39.50; 53.39; 58.25; 68.87; 69.50; 76.23; 106.41; 127.13; 129.90; 130.53; 132.49; 134.16; 135.55; 145.34; 150.67; 171.54.

Elemental analysis calc. (%) for C₁₈H₂₃Cl₂N₃O₅ (432.30): C 50.01; H 5.36; N 9.72. Found: C 49.69; H 4.97; N 10.00.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium D,L-lactate (26). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.29 (m, 7H); 3.24 (m, 1H); 3.89 (m, 1H); 4.06 (m, 2H); 4.74 (m, 2H); 7.42 (m, 2H); 7.64 (s, 1H); 7.88 (d, J = 10.1 Hz, 1H); 8.43 (d, J = 2.1 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.81; 18.44; 20.46; 34.17; 65.82; 69.53; 76.26; 77.34; 106.45; 127.18; 129.93; 130.55; 132.52; 134.37; 135.56; 145.36; 150.69; 176.38.

Elemental analysis calc. (%) for C₁₈H₂₃Cl₂N₃O₅ (432.30): C 50.01; H 5.36; N 9.72. Found: C 50.35; H 5.72; N 9.38.

(±)-1-[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazol-4-ium maleate (27). ¹H NMR (DMSO-d₆) δ (ppm) 0.86 (m, 3H); 1.30 (m, 4H); 3.21 (m, 1H); 3.91 (m, 2H); 4.75 (m, 2H); 6.33 (m, 2H); 7.40 (m, 2H); 7.67 (s, 1H); 7.89 (d, J = 10.2 Hz, 1H); 8.44 (d, J = 1.9 Hz, 1H). ¹³C NMR (DMSO-d₆) δ (ppm) 13.83; 18.46; 39.50; 69.58; 76.31; 106.49; 127.20; 128.64; 129.95; 130.59; 131.22; 131.57; 132.57; 134.43; 145.38; 150.69; 166.92.

Elemental analysis calc. (%) for C₁₉H₂₁Cl₂N₃O₆ (458.29): C 49.79; H 4.62; N 9.17. Found: C 49.49; H 4.89; N 8.85.

Thermal stability

Thermal transition temperatures were determined by DSC, with a Mettler Toledo Star^e DSC1 (Leicester, UK) unit, under nitrogen. Samples (between 5 and 15 mg) were placed in aluminum pans and heated from 25 to 120 °C at a heating rate of 10 °C min⁻¹, cooled with an intracooler at a cooling rate of 10 °C min⁻¹ to −100 °C, then heated again to 120 °C. Thermogravimetric analysis was performed using a Mettler Toledo Star^e TGA/DSC1 unit (Leicester, UK), under nitrogen. Samples (between 2 and 10 mg) were placed in aluminium pans and heated from 30 to 450 °C at a heating rate of 10 °C min⁻¹.

Antifungal activity

Four species of fungi were used: Fusarium culmorum, Sclerotinia sclerotiorum, Microdochium nivale and Botrytis cinerea (obtained from the Institute of Plant Protection-NRI collection). The sample of tested salts was dissolved in 4 mL of methanol, isopropanol or water, then added to a sterile medium (PDA – Potato Dextrose Agar, Difco™) and cooled to 50 °C. The concentration of the studied salt in the medium was 10, 100 or 1000 ppm. Liquid medium containing the tested salts was distributed on the Petri dishes (diameter of 50 mm). The 4 mm disks of the examined fungi were placed in the center of the Petri dish. In the control sample, the fungi were grown on PDA with the addition of sterile water. The tested salts were compared with commercial fungicides (Tebu 250 EW and Bumper 250 EC) containing tebuconazole or propiconazole as an active substance. The plates were incubated in room temperature until the mycelium in the control reached the edge of the Petri dish. Afterwards, the diameter of the mycelium was measured, subtracting the initial diameter of the disc with the fungus (4 mm). Four replications were performed for each experimental sample. The results were subjected to Student–Newman–Keuls's analysis to test for significant differences between control and samples with addition of ILs.

Acknowledgements

This work was supported by 03/32/DSPB 445, Poznan University of Technology, Department of Chemical Technology.

Notes and references

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5. L. G. Golubyatnikova, R. A. Khisamutdinov and Y. I. Murinov, Russ. J. Inorg. Chem., 2013, 58, 1259.
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Footnote

† Electronic supplementary information (ESI) available. See DOI: 10.1039/c4ra12160k

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