2,4-D based herbicidal ionic liquids

Article abstract of DOI:10.1016/j.tet.2012.03.065

Herbicidal ionic liquids (HILs) with a 2,4-D anion were synthesized and characterized. These salts have chemical and thermal stability. HILs exhibited higher biological activity than currently used salts of 2,4-D. HILs are nonvolatile and showed substantially lower water solubility than starting herbicides.

Full text of DOI:10.1016/j.tet.2012.03.065

Tetrahedron 68 (2012) 4267e4273
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
2,4-D based herbicidal ionic liquids
,
a
a
b
c
Juliusz Pernak a , Anna Syguda , Katarzyna Materna , Ewa Janus , Przemys1aw Kardasz ,
*
Tadeusz Praczyk c
a Department of Chemical Technology, Poznan University of Technology, Poznan 60-965, Poland
b Department of Organic Chemical Technology, West Pomeranian University of Technology, Szczecin, Szczecin 70-322, Poland
c Institute of Plant Protection, National Research Institute, Poznan 60-318, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Herbicidal ionic liquids (HILs) with a 2,4-D anion were synthesized and characterized. These salts have
chemical and thermal stability. HILs exhibited higher biological activity than currently used salts of 2,4-D.
HILs are nonvolatile and showed substantially lower water solubility than starting herbicides.
Ó 2012 Elsevier Ltd. All rights reserved.
Received 8 November 2011
Received in revised form 1 March 2012
Accepted 19 March 2012
Available online 28 March 2012
Keywords:
Ionic liquids
2,4-D
Biological activity
1. Introduction
Ionic liquids (ILs) represent a new class of non-molecular liquids
with unique and fascinating properties offering a phenomenal
(2,4-Dichlorophenoxy)acetic acid (2,4-D) was first described by
Zimmerman and Hitchcock.1 This phenoxy acid is a systemic her-
bicide used in the control of broadleaf weeds and is also a synthetic
auxin often used in laboratories for plant research. It has been
researched in various capacities by scientists and government
regulatory agencies for more than six decades. Owing to the lon-
gevity and extent of use, 2,4-D is among the most thoroughly
studied herbicides with respect to its environmental properties.
Despite its short half-life in soil and in aquatic environments, the
compound has been detected in groundwater supplies. It has also
been detected in surface waters throughout the United States at
very low concentrations. Concern over 2,4-D is such that it is cur-
rently not approved for use on lawns and gardens in Sweden,2
opportunity for science and technology.6e10 The evaluation of these
compounds progresses very quickly from the first generation (ILs
with unique tunable physical properties) to the second generation
(ILs with targeted chemical properties combined with selected
physical properties), and to the third generation (ILs with targeted
biological properties combined with chosen physical and chemical
properties).11e17 Recently the third generation has been extended
by phytopharmaceuticalsdherbicidal ionic liquids.18
The structures of commercial 2,4-D-ammonium salts are shown
in Fig. 1, with the abbreviations and melting points. The two am-
monium salts can be classified as the protic ionic liquids (diolamine
and triisopropanolammonium). These two examples contain sec-
ondary and tertiary 2,4-D-ammonium salts. Lately Dow Agro-
sciences LLC patent19 describes seven quaternary 2,4-D-ammonium
salts (inter alia 2,4-D-teraalkylammonium, 2,4-D-benzyl-
trimethylammonium, and 2,4-D-hexadecyltrimethylammonium).
Denmark, Norway, Kuwait, and the Canadian provinces of
3
Quebec and Ontario.4 Generally, 2,4-D does not present risk to
ꢀ
human health or the environment when used according to the
label.
The available, on-the-market herbicides utilizing 2,4-D contain
this active phenoxy acid in several forms, including acid, salts, and
esters.5 Esters are more active in comparison with acids and salts.
However, they have the disadvantage of being very volatile.
2. Results and discussion
Freshly crystallized (2,4-dichlorophenoxy)acetic acid, charac-
terized by melting point Tm¼139e140 ꢀC, was used in the synthesis.
The sources of cations were quaternary ammonium, pyridinium,
imidazolium, piperidinium, morpholinium, and pyrrolidinium ha-
lides. Structure of cations and abbreviation used in this paper are
presented in Fig. 2. The prepared quaternary ammonium (N) salts
(Scheme 1) and synthesized pyridinium (Pyr), imidazolium (Im),
* Corresponding author. Tel.: þ48 61 665 3682; fax: þ48 61 665 3649; e-mail
address: juliusz.pernak@put.poznan.pl (J. Pernak).
0040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2012.03.065

4268
J. Pernak et al. / Tetrahedron 68 (2012) 4267e4273
All synthesized salts are liquid or grease, except N-8
(Tm¼86e87.5 ꢀC) and Pyr-2 (Tm¼132e134 ꢀC). These new salts,
except Pyr-2, may be considered as ILs. Pyr-2 is a salt, PP vitamin
derivative. This kind of salt is usually characterized by a high
melting point.21
Synthesized ILs are stable in air and in contact with water and
common organic solvents. They can be made anhydrous by heating
at 70 ꢀC in vacuo and storing them over P4O10. The water content
was determined to be less than 500 ppm by coulometric
KarleFischer titration.
The obtained ILs were soluble in DMSO, alcohols (methanol,
ethanol, and propanol), and chloroform. All synthesized ILs are
insoluble in hexane and diethyl ether. Selection of the cation de-
termined the hydrophilicity of the synthesized ILs. Limited solu-
bility in water was observed when using large ammonium cations
with long alkyl substituents (Table 1).
The synthesized new ILs were characterized by 1H and 13C NMR
spectroscopy and elemental analysis. In the 1H NMR spectra the
proton chemical shifts were observed for the protons located
around the quaternary nitrogen atom coming up to 0.5 ppm. These
chemical shift values are lower than the corresponding signals from
the precursor, indicating that the 2,4-D anion causes greater
shielding of the protons. The 13C NMR spectra of the studied ILs
indicated no significant variation in the carbon signal shifts, which
is consistent with our earlier observations.22
Data presented in Table 3 show that the prepared quaternary
2,4-D-ammonium ILs were thermally stable. They have glass tran-
sition temperatures in the area from ꢁ35 to ꢁ54 ꢀC. N-4, N-7, and
N-8 do not have the glass transition temperature. Some ammonium
ILs like N-2, N-7, N-4, and N-8 have a melting point. In the case of N-
8 two different melting points depending on the measuring tech-
nique are observed. A higher value indicated differential scanning
calorimetry of at 108 ꢀC in comparison with the measure for the
resulting crystalline form 86e87.5 ꢀC.
Fig. 1. Structures of commercial primary, secondary, and tertiary 2,4-D-ammonium
salts.
R2
R2
N+ CH3
R2
N+
R1
N
N+
R1
R
CH3
The prepared new forms of 2,4-D have been investigated under
field conditions. The results of trials established on a field heavily
infested by dicot weed species showed that 2,4-D as ILs (N-1 and N-
2) gave excellent control of common lambsquarters (Chenopodium
album), field pennycress (Thlaspi arvense), and shepherd’s-purse
(Capsella bursa pastoris). Standard herbicide containing 2,4-D as
the sodium salt was much less effective (Table 4). Moreover, it is
interesting that the studied ILs have shown much faster effects on
weeds than standard herbicide. This aspect is very profitable for
growers because the weed competition can be eliminated in a few
days after ILs application.
(N)
(Pyr)
(Im)
imidazolium
quaternary ammonium pyridinium
O
N+
N+
N+
CH3
CH3
CH3
R
R
R
(Pip)
piperidinium
(Mor)
morpholinium
(Pyrr)
pyrrolidinium
In another experiment conducted on spring barley we found
excellent weed control using this form of 2,4-D. The efficacy of N-6
was similar to that of 2,4-D-ethylhexyl ester and it was much better
compared to the 2,4-D-dimethylammonium salt (Table 5). It is also
important that a quaternary 2,4-D-ammonium salt applied at til-
lering growth stage at a rate of 450 g a.i. haꢁ1 did not cause any
symptoms of injury on spring barley plants. The obtained results
allow us to qualify the tested salts as herbicidal ionic liquids (HILs).
Because HILs are nonvolatile compounds they are more safe to the
operators and to the nontarget plants compared to esters, moreover
they are relatively safe to transport and store.
Fig. 2. Structure of cations of prepared 2,4-D-salts.
piperidinium (Pip), morpholinium (Mor), and pyrrolidinium (Pyrr)
salts are summarized in Tables 1 and 2, respectively. Using 2,4-D in
comparison with MCPA (4-chloro-2-methylphenoxy)acetic acid
(MCPAdherbicidal activity reported by Slade20) meant that we had
to change the method of synthesis described before.18 The me-
tathesis reaction run easier for MCPA in comparison with 2,4-D.
These phenoxy acids have similar pKa values (3.73 and 2.73 for
MCPA and 2,4-D, respectively5), however react in a different way.
The surface activity of the cation affects the herbicidal efficiency
of the studied salt. Fig. 3 shows surface tension as a function of
concentration for the three synthesized quaternary 2,4-D-ammo-
nium salts. Critical micelle concentration (CMC), surface tension, and
contact angle values are shown in Table 6. In addition, surface ac-
tivity for didecyldimethylammonium (4-chloro-2-methylphenoxy)
acetate is given. Comparing the designated values for obtained
HILs: N-2 and N-2-MCPA (the second HIL has the same cation and
only the differ anion), it is observed no significant differences. Anion
in this case is not weakened the surface activity of the cation.
O
O
R2
N+
R2
O
R2
N+
R2
O
O-
R1
OX
+
Y-
R1
XY
+
CH3
Cl
Cl
CH3
Cl
Cl
where X = H or Na, Y = Cl, Br, I, OH
Scheme 1. Synthesis of quaternary 2,4-D-ammonium salts.

J. Pernak et al. / Tetrahedron 68 (2012) 4267e4273
4269
Table 1
The prepared quaternary 2,4-D-ammonium salts
Salt
R1
R2
R3
Yield (%)
Purity (%)
State at 25 ꢀ
C
Solubility in water
N-1
N-2
N-3
N-4
N-5
N-6
N-7
N-8
N-9
N-10
CH3
CH3
CH3
CH3
C12H25
Alkylc
CH3
CH3
CH3
CH2C6H5
C10H21
C12H25
CH3
Alkyla
C10H21
81
91
88
99
77
95
97
96
92
90
99.0
99.5
99.0
99.5
99.0
99.0
99.0
99.0
99.0
d
Liquid
Liquid
Liquid
Grease
Liquid
Grease
Liquid
Solidf
Limited
Limited
Limited
Limited
Total
C6H5OCH2CH2
C16H33
(CH2CH2O)xHb
(CH2CH2O)xHd
Alkyle
(CH2CH2O)yHb
(CH2CH2O)yHd
Alkyle
Total
Limited
Limited
Total
cyclo-C12H23OCH2
C10H21SCH2
CH2]CHCH2
CH2CH2OH
CH2CH2OH
CH2]CHCH2
Grease
Grease
CH3
Total
a
Alkyl chain distribution C12
H
25d60, C14
25d1, C14
H
29d40%.
b
c
d
e
f
xþy¼15.
Oleyl chain distribution C12
xþy¼2.
H
H29d4, C16
H
33d12, C18H35d82%.
Alkyl (hydrogenated tallow chain distribution C12
H
25d1, C14 29d4, C16H33d31, C18H37d64%).
H
Mp 86e87.5 ꢀC.
Table 2
Table 5
The influence of different forms of 2,4-D on weed control in spring barley (4 WATa)
The prepared 2,4-D-imidazolium (Im), 2,4-D-pyridinium (Pyr), 2,4-D-piperidinium
(Pip), 2,4-D-morpholinium (Mor), and 2,4-D-pyrrolidinium (Pyrr) salts
Treatments
Rate of 2,4-D
Chenopodium
album
Centaurea
cyanus
R1
R2
Yield (%) State at 25 ꢀ
C
Solubility in water
(g haꢁ1
)
Salt
Im-1
Im-2
Im-3
Pyr-1
Pyr-2
Pip-1
Pip-2
Pip-3
C8H17OCH2
C8H17SCH2
C4H9
C16H33
CH3
CH3
C3H7OCH2
C5H11OCH2
d
d
d
H
96
91
90
99
Grease
Liquid
Grease
Grease
Solida
Grease
Liquid
Liquid
Grease
Liquid
Total
Total
Total
Total
Total
Total
Total
Total
Total
Total
% Weed
control
100
60
100
N-6
450
450
450
100
20
80
2,4-D-Dimethylammonium
2,4-D-Ethylhexyl
CONH2 91
d
d
d
d
d
82
98
97
98
99
a
WAT¼weeks after treatment.
Mor-1 C4H9
Pyrr-1 C4H9
a
Mp¼132e134 ꢀC with decomposition.
Table 3
The physicochemical properties of 2,4-D-quaternary ammonium ILs
a
b
c
d
e
IL
Tg (ꢀC)
Tcryst (ꢀC)
Tm (ꢀC)
Tonset5% (ꢀC)
Tonset (ꢀC)
N-1
N-2
N-3
N-4
N-5
N-6
N-7
N-8
N-9
N-10
ꢁ51
ꢁ50
ꢁ42
d
d
ꢁ39f
d
204
208
214
218
219
222
219
242
205
187
252
260
273
253, 335
285, 372
244
256, 330
280
ꢁ3
d
d
d
ꢁ20
d
ꢁ54
ꢁ55
d
d
d
d
d
16
108
d
d
d
ꢁ35
ꢁ42
d
219, 272
196, 237
d
d
a
Tgdglass transition temperature.
b
c
d
e
f
T
T
T
crystdtemperature of crystallization.
mdmelting point.
onset5%ddecomposition temperature of 5% sample.
Fig. 3. Surface tension as a function of concentration (log C) of HILs at 25 ꢀC in water.
T
onsetddecomposition temperature.
Tcold crystallization¼ꢁ20 ꢀC.
Table 6
The CMC, surface tension (gCMC), and contact angle CA (paraffin) of aqueous solution
Table 4
of HILs, at 25 ꢀ
C
Weed control on fallow by different forms of 2,4-D
HIL
CMC (mmol Lꢁ1
)
gCMC (mN mꢁ1
)
CA (ꢀ)
Treatments
Concent. Chenopodium
Thlaspi arvense
Capsella bursa
pastoris
album
N-1
N-2
0.501
0.316
0.158
0.251
31.2
26.6
32.5
26.2
49.4
33.0
51.8
33.2
(M)
6 DATa 30 DAT 6 DAT 30 DAT 6 DAT 30 DAT
N-6
N-2-MCPAa
% Weed control
N-1
N-1
N-2
N-2
0.01
0.02
0.01
0.02
85
97
89
98
55
100
100
100
100
25
81
90
82
96
31
100
100
100
100
100
81
96
81
99
28
100
100
100
100
100
a
Didecyldimethylammonium (4-chloro-2-methylphenoxy)acetate.18
3. Conclusion
2,4-D-sodium 0.01
salt
2,4-D-sodium 0.02
salt
60
75
48
100
55
100
New forms of 2,4-D as ionic liquids were synthesized. The
synthesized salts are thermally stable. Their solubility in water can
be regulated by selection of the cation. In synthesized ILs with the
a
DAT¼days after treatment.

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J. Pernak et al. / Tetrahedron 68 (2012) 4267e4273
2,4-D anion, the herbicidal activity of the anion was increased.
According to the law in force, with a view to the environmental
protection, the proposed HILs with 2,4-D anion pose a real possi-
bility of extending the applications one of the most important
herbicide (2,4-D). HILs are nonvolatile. Additionally, lower water
solubility than starting herbicides, is likely to reduce soil and
groundwater mobility.
2.5 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.91 (1H, d, J 8.9 Hz, HCCH]CO),
4.47 (2H, s, OCH2COOꢁ), 3.29 (4H, t, J 8.4 Hz, CH2NþCH2), 3.20 (6H, s,
MeNþMe), 1.60 (4H, q, J 7.3 Hz, CH2CH2NþCH2CH2), 1.26 (28H, m,
CH2(CH2)7Me), 0.88 (6H, t, J 6.7 Hz, (CH2Me)2); dC (75 MHz, CDCl3)
171.3, 153.6, 129.1, 127.2, 124.3, 122.3, 114.5, 69.1, 63.2, 50.7, 31.7,
29.31, 29.27, 29.12, 29.10, 28.9, 26.2, 22.5, 14.0.
4.2.3. Dodecyldimethylphenoxyethylammonium (2,4-dichloropheno-
xy)acetate (N-3). Found: C, 64.59; H, 8.19; N, 2.62. C30H45O4NCl2
requiresC, 64.96; H, 8.19; N, 2.53%. nmax (liquid film) 3600e3100 (br),
2924, 2854, 1613, 1483, 1430, 1391, 1347, 1283, 1265, 1241, 1064, 801,
4. Experimental section
4.1. General
755, 691 cmꢁ1
; dH (300 MHz, CDCl3) 7.29 (2H, t, J 4.5 Hz, meta-Ph),
1H NMR spectra were recorded on a Mercury Gemini 300
spectrometer operating at 300 MHz with tetramethylsilane as the
internal standard. 13C NMR spectra were obtained with the same
instrument at 75 MHz. CHN elemental analyses were performed at
Adam Mickiewicz University, Poznan (Poland). The water content
was determined by using an Aquastar volumetric KarleFischer ti-
tration with Composite 5 solution as the titrant and anhydrous
methanol as solvent.
7.25 (1H, d, J 2.5 Hz, ClCCH]CCl), 7.06 (1H, dd, J1,2 2.7 Hz, J1,3 9.0 Hz,
ClC]CHCCl), 7.00 (1H, t, J 8.4 Hz, para-Ph), 6.87 (1H, d, J 9.1 Hz,
HCCH]CO), 6.84 (2H, d, J 3.2 Hz, ortho-Ph), 4.45 (2H, s, OCH2COOꢁ),
4.37 (2H, t, J 3.8 Hz, OCH2CH2Nþ), 3.99 (2H, t, J 4.3 Hz, OCH2CH2Nþ),
3.38 (2H, t, J 8.5 Hz, NþCH2CH2), 3.27 (6H, s, MeNþMe), 1.70 (2H, q, J
7.3 Hz, NþCH2CH2),1.25 (18H, m, CH2(CH2)9Me), 0.88 (3H, t, J 6.7 Hz,
CH2Me); dC (75 MHz, CDCl3) 172.0, 156.8, 153.4, 129.6, 129.3, 127.4,
124.6, 122.4, 121.8, 114.5, 114.1, 69.0, 65.6, 62.2, 61.9, 51.7, 31.9, 29.6,
29.5, 29.3, 29.2, 26.3, 22.8, 22.7, 14.1.
4.2. Preparation
4.2.4. Hexadecyltrimethylammonium (2,4-dichlorophenoxy)acetate
(N-4). Found: C, 63.98; H, 9.47; N, 2.71. C28H43O3NCl2 requires C,
64.26; H, 9.41; N, 2.78%. nmax (thin film) 3600e3100 (br), 3017,
2918, 2850, 1644, 1609, 1484, 1430, 1346, 1282, 1242, 1107, 1064,
Quaternary 2,4-D-ammoniums (N-1)e(N-9), 2,4-D-imidazolium
(Im-1), (Im-2), and 2,4-D-pyrrolidinium (Pyr-1) salts: (2,4-Dichlor-
ophenoxy)acetic acid (0.01 mol), distilled water (20 mL), and a 10%
aqueous solution of NaOH (0.011 mol) were mixed in a round-
bottomed flask, equipped with a magnetic stirring bar, a reflux
condenser, and an addition funnel. The mixture was heated at 50 ꢀC
until it became a clear solution. After that the quaternary ammo-
nium or imidazolium or pyrrolidinium chloride or bromide
(0.01 mol) dissolved in water (30 mL) was added and stirred for
30 min at room temperature. Then product was extracted from the
aqueous phase with chloroform (50 mL) and washed with distilled
water until chloride or bromide ions were no longer detected using
AgNO3. After removal of chloroform the product was dried under
reduced pressure at 70 ꢀC for 24 h.
Quaternary 2,4-D-ammonium (N-1), 2,4-D-imidazolium (Im-3),
2,4-D-pyridinium (Pyr-2), 2,4-D-piperidinium (Pip-2), (Pip-3), 2,4-
D-morpholinium (Mor-1) and 2,4-D-pyrrolidinium (Pyrr-1) salts:
Quaternary ammonium or imidazolium or pyridinium or piper-
idinium or morpholinium or pyrrolidinium chloride, bromide or
iodide (0.01 mol) was exchanged into OH ion using anion exchange
resin Dowex-Monosphere 550A (OH). After that was added (2,4-
dichlorophenoxy)acetic acid (0.011 mol). The mixture was stirred
for 10 min. Then excess of (2,4-dichlorophenoxy)acetic acid was
filtered out, and water was evaporated. Finally product was dried
under reduced pressure at 70 ꢀC for 24 h.
1044, 961, 868, 801 cmꢁ1
; dH (300 MHz, CDCl3) 7.28 (1H, d, J 2.5 Hz,
ClCCH]CCl), 7.13 (1H, dd, J1,2 2.5 Hz, J1,3 8.7 Hz, ClC]CHCCl), 6.86
(1H, d, J 8.8 Hz, ClC]CHCCl), 4.43 (2H, s, OCH2COOꢁ), 3.20 (2H, t, J
8.5 Hz, NþCH2CH2), 3.13 (9H, s, (Me)3Nþ), 1.59 (2H, q, J 7.3 Hz,
NþCH2CH2), 1.26 (26H, m, CH2(CH2)13CH3), 0.88 (3H, t, J 6.7 Hz,
CH2Me); dC (75 MHz, CDCl3) 172.2, 153.1, 129.3, 127.5, 124.9, 122.5,
114.6, 68.4, 66.6, 53.0, 31.9, 29.70, 29.65, 29.59, 29.52, 29.34, 29.31,
26.3, 23.0, 22.7, 14.1.
4.2.5. Dodecyldi(polyoxyethylene)methylammonium (2,4-
dichlorophenoxy)acetate (N-5). nmax (liquid film) 3600e3100 (br),
2923, 2854, 1616, 1483, 1348, 1283, 1245, 1106, 1042, 948, 868,
801 cmꢁ1
; dH (300 MHz, CDCl3) 7.30 (1H, d, J 2.5 Hz, ClCCH]CCl),
7.09 (1H, dd, J1,2 2.5 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.90 (1H, d, J 9.1 Hz,
HCCH]CO), 4.49 (2H, s, OCH2COOꢁ), 3.86 (4H, m, (CH2CH2OH)2),
3.70 (4H, m, Nþ(CH2CH2O)2), 3.65 (52H, m, (CH2CH2O)13), 3.43 (2H,
t, J 6.6 Hz, NþCH2CH2), 3.21 (3H, s, MeNþ), 1.68 (2H, m, NþCH2CH2),
1.26 (18H, m, CH2(CH2)9Me), 0.88 (3H, t, J 7.0 Hz, CH2Me); dC
(75 MHz, CDCl3) 171.8, 153.7, 129.1, 127.2, 124.3, 122.6, 114.6, 72.67,
72.61, 72.58, 72.55, 72.45, 70.36, 70.3, 70.2, 70.0, 69.98, 69.80, 68.9,
64.7, 63.8, 61.5, 61.23, 61.18, 61.13, 61.06, 60.9, 49.0, 31.7, 29.5, 29.39,
29.31, 29.28, 29.1, 29.0, 26.1, 22.5, 22.3, 13.9.
4.2.1. Benzalkonium (2,4-dichlorophenoxy)acetate (N-1). nmax (liq-
uid film) 3600e3100 (br), 2925, 2854, 1615, 1483, 1391, 1347, 1284,
4.2.6. Oleyldi(2-hydroxyethyl)methylammonium (2,4-
dichlorophenoxy)acetate (N-6). nmax (thin film) 3500e3100 (br),
2924, 2854, 1615, 1482, 1430, 1346, 1282, 1266, 1243, 1106, 1065,
1265, 1237, 1065, 725, 704 cmꢁ1
; dH (300 MHz, CDCl3) 7.44 (5H, m,
Ph), 7.22 (1H, d, J 2.5 Hz, ClCCH]CCl), 7.03 (1H, dd, J1,2 2.5 Hz, J1,3
8.8 Hz, ClC]CHCCl), 6.87 (1H, d, J 9.1 Hz, HCCH]CO), 4.50 (2H, s,
OCH2COOꢁ), 4.70 (2H, s, CH2Ph), 3.24 (2H, t, J 8.4 Hz, NþCH2CH2),
3.09 (6H, s, MeNþMe), 1.68 (2H, q, J 7.3 Hz, NþCH2CH2), 1.26 (20H,
m, CH2(CH2)10CH3), 0.88 (3H, t, J 6.7 Hz, CH2Me); dC (75 MHz,
CDCl3) 171.8, 153.5, 132.8, 130.3, 129.2, 128.9, 127.4, 127.3, 124.4,
122.4, 114.5, 70.0, 67.4, 63.2, 49.5, 31.86, 31.84, 29.63, 29.59, 29.54,
29.43, 29.37, 29.3, 29.2, 26.3, 22.7, 22.6, 14.1.
1043, 868, 801 cmꢁ1
; dH (300 MHz, CDCl3) 7.31 (1H, d, J 2.8 Hz,
ClCCH]CCl), 7.13 (1H, dd, J1,2 2.6 Hz, J1,3 8.9 Hz, ClC]CHCCl), 6.83
(1H, d, J 9.1 Hz, HCCH]CO), 5.35 (2H, m, CH]CH), 4.45 (2H, s,
OCH2COOꢁ), 3.96 (4H, t, J 4.0 Hz, Nþ(CH2CH2OH)2), 3.54 (4H, t, J
4.3 Hz, Nþ(CH2CH2OH)2), 3.34 (2H, t, J 8.4 Hz, NþCH2CH2), 3.14 (3H,
s, MeNþ), 2.00 (4H, m, CH2CH]CHCH2), 1.26 (26H, m,
CH2(CH2)13Me), 0.88 (3H, t, J 6.9 Hz, CH2Me); dC (75 MHz, CDCl3)
173.1, 153.3, 129.9, 129.51, 129.48, 127.5, 125.1, 122.8, 114.5, 68.6,
64.1, 63.6, 55.5, 50.0, 32.5, 31.81, 31.80, 31.7, 29.64, 29.62, 29.61,
29.56, 29.50, 29.46, 29.42, 29.38, 29.33, 29.26, 29.22, 29.17, 29.13,
29.09, 29.04, 27.12, 27.10, 27.07, 26.3, 22.6, 22.4, 14.0.
4.2.2. Didecyldimethylammonium (2,4-dichlorophenoxy)acetate (N-
2). Found: C, 65.7; H, 9.85; N, 2.68. C30H53O3NCl2 requires C, 65.90;
H, 9.79; N, 2.56%. nmax (liquid film) 3600e3100 (br), 2925, 2855,
1614, 1483, 1390, 1347, 1283, 1265, 1242, 1105, 1065, 801 cmꢁ1
;
dH
4.2.7. Di(hydrogenatedtallowalkyl)dimethylammonium (2,4-
dichlorophenoxy)acetate (N-7). nmax (liquid film) 2923, 2853, 1620,
(300 MHz, CDCl3) 7.29 (1H, d, J 2.6 Hz, ClCCH]CCl), 7.09 (1H, dd, J1,2

J. Pernak et al. / Tetrahedron 68 (2012) 4267e4273
4271
1482, 1468, 1389, 1284, 1264, 1065, 722 cmꢁ1
;
dH (300 MHz, CDCl3)
requires C, 64.65; H, 10.46; N, 11.60%. nmax (liquid film) 3600e3100
7.29 (1H, d, J 2.6 Hz, ClCCH]CCl), 7.11 (1H, dd, J1,2 2.7 Hz, J1,3 8.8 Hz,
ClCCH]CCl), 6.89 (1H, d, J 8.8 Hz, HCCH]CO), 4.46 (2H, s,
OCH2COOꢁ), 3.25 (4H, t, J 8.4 Hz, CH2NþCH2), 3.18 (6H, s, MeNþMe),
(br), 3143, 3095, 2955, 2926, 2854,1643,1611,1482,1430,1346,1282,
1266,1242,1106,1065, 868, 801, 764 cmꢁ1
;dH (300 MHz, CDCl3) 10.19
(1H, t, J 1.1 Hz, NCH]Nþ), 7.50 (1H, t, J 1.8 Hz, MeNCH]CHNþ), 7.38
(1H, t, J 1.8 Hz, MeNCH]CHNþ), 7.28 (1H, d, J 2.5 Hz, ClCCH]CCl),
7.11 (1H, dd, J1,2 2.6 Hz, J1,3 8.9 Hz, ClC]CHCCl), 6.89 (1H, d, J 8.9 Hz,
HCCH]CO),5.33(2H, s, NþCH2S), 4.48(2H, s, OCH2COOꢁ), 3.90 (3H, s,
MeN), 2.52 (2H, t, J 7.3 Hz, SCH2CH2), 1.49 (2H, q, J 7.3 Hz, SCH2CH2),
1.23(10H, m, CH2(CH2)5Me), 0.87(3H, t, J 6.8 Hz, CH2Me);dC (75 MHz,
CDCl3) 172.5,153.3,138.4,129.4,127.4,124.8,123.4,122.5,121.1,114.5,
68.7, 51.3, 36.2, 31.7, 31.6, 29.0, 28.6, 28.5, 22.5, 13.9.
1.59 (4H, q,
J
6.9 Hz, CH2CH2NþCH2CH2), 1.26 (50H, m,
CH2(CH2)25Me), 0.88 (6H, t, J 6.9 Hz, (CH2Me)2); dC (75 MHz, CDCl3)
172.0, 153.6, 129.3, 127.4, 124.6, 122.5, 114.6, 68.9, 63.2, 51.1, 31.8,
29.6, 29.54, 29.50, 29.4, 29.3, 29.2, 29.1, 26.1, 22.6, 22.5, 14.0.
4.2.8. Cyclododecyloxymethyl(2-hydroxyethyl)dimethylammonium
(2,4-dichlorophenoxy)acetate (N-8). Found: C, 59.00; H, 8.07; N, 2.65.
C25H41O5NCl2 requires C, 59.27; H, 8.17; N, 2.77%. nmax (pellet with KBr)
3219, 2929, 2903, 2862, 2845, 1611, 1473, 1399, 1346, 1267, 1138, 1065,
4.2.13. 1-Butyl-3-methylimidazolium (2,4-dichlorophenoxy)acetate
(Im-3). Found: C, 53.20; H, 5.53; N, 8.11. C16H20O3N2Cl2 requires C,
53.48; H, 5.62; N, 8.00%. nmax (liquid film) 3600e3100 (br), 3148,
3093, 2961, 2935, 1613, 1573, 1482, 1424, 1397, 1346, 1283, 1266,
812, 801 cmꢁ1
; dH (300 MHz, CDCl3) 7.31 (1H, d, J 2.7 Hz, ClCCH]CCl),
7.11 (1H, dd, J1,2 2.5 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.85 (1H, d, J 9.1 Hz,
HCCH]CO), 6.06 (1H, s, CH2OH), 4.72 (2H, s, NþCH2O), 4.44 (2H, s,
OCH2COOꢁ), 3.99 (2H, t, J 4.5 Hz, NþCH2CH2OH), 3.78 (1H, q, J 3.7 Hz,
CH2OCH), 3.51 (2H, t, J 4.7 Hz, NþCH2CH2OH), 3.12 (6H, s, MeNþMe),
1.65 (2H, m, HaHbCOCHaHbdcyclic), 1.49 (2H, m, CHaHbCHaHbCO-
CHaHbCHaHbdcyclic), 1.32 (18H, m, (CH2)7dcyclic and CHaHbCO-
CHaHbdcyclic and CHaHbCHaHbCOCHaHbCHaHbdcyclic); dC (75 MHz,
CDCl3) 172.2,153.4,129.3,127.3,124.8,122.6,114.4, 89.7, 81.4, 68.7, 63.0,
55.4, 48.0, 28.4, 24.8, 24.5, 22.6, 22.4, 19.8.
1241, 1170, 1106, 1066, 801, 770 cmꢁ1
; dH (300 MHz, DMSO-d6)
10.05 (1H, t, J 1.1 Hz, NCH]N), 7.90 (1H, t, J 1.9 Hz, MeNCH]CHNþ),
7.84 (1H, t, J 1.9 Hz, MeNCH]CHNþ), 7.54 (1H, d, J 2.5 Hz, ClCCH]
CCl), 7.35 (1H, dd, J1,2 2.5 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.97 (1H, d, J
8.9 Hz, HCCH]CO), 4.38 (2H, s, OCH2COOꢁ), 4.28 (2H, t, J 7.1 Hz,
NþCH2CH2), 3.95 (3H, s, MeN), 1.87 (2H, q, J 7.4 Hz, NþCH2CH2CH2),
1.38 (2H, sex, J 7.4 Hz, CH2CH2Me), 0.98 (3H, t, J 7.3 Hz, CH2Me); dC
(75 MHz, DMSO-d6) 179.4, 153.7, 136.8, 128.8, 127.6, 123.6, 123.3,
122.3, 121.9, 115.1, 68.5, 48.57, 35.7, 31.4, 18.8, 13.3.
4.2.9. Decylthiomethyl(2-hydroxyethyl)dimethylammonium (2,4-
dichlorophenoxy)acetate (N-9). Found: C, 55.26; H, 8.01; N, 2.93.
C23H39O4NSCl2 requires C, 55.62; H, 7.93; N, 2.82%. nmax (thin film)
4.2.14. 1-Hexadecylpyridinium (2,4-dichlorophenoxy)acetate (Pyr-1).
Found: C, 65.99; H, 8.52; N, 2.62. C29H43O3NCl2 requires C, 66.39; H,
8.28; N, 2.67%. nmax (thin film) 3052, 2923, 2852, 1611, 1485, 1429,
2925, 2854, 1612, 1480, 1392, 1339, 1287, 1104, 1065, 868, 801 cmꢁ1
;
dH (300 MHz, CDCl3) 7.32 (1H, d, J 2.5 Hz, ClCCH]CCl), 7.13 (1H, dd,
J
1,2 2.6 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.84 (1H, d, J 8.8 Hz, HCCH]CO),
1391,1283,1239,1065, 867, 800 cmꢁ1
; dH (300 MHz, CDCl3) 9.01 (2H,
4.73 (2H, s, NþCH2S), 4.45 (2H, s, OCH2COOꢁ), 3.99 (2H, t, J 4.5 Hz,
NþCH2CH2OH), 3.58 (2H, t, J 4.5 Hz, NþCH2CH2OH), 3.14 (6H, s,
MeNþMe), 2.75 (2H, t, J 7.3 Hz, SCH2CH2), 1.56 (2H, q, J 7.3 Hz,
SCH2CH2),1.25 (14H, m, CH2(CH2)7Me), 0.88 (3H, t, J 6.7 Hz, CH2Me);
dC (75 MHz, CDCl3) 172.6, 153.4, 129.5, 127.5, 125.0, 122.7, 114.4, 70.7,
68.7, 65.0, 55.8, 49.6, 35.9, 31.8, 29.51, 29.45, 29.39, 29.2, 29.1, 28.5,
22.6, 14.0.
d, J 5.5 Hz, CH]NþCH), 8.42 (1H, t, J 7.8 Hz, CH]CHCH]Nþ), 8.02
(2H, t, J 7.1 Hz, CHCH]NþCH]CH), 7.25 (1H, d, J 2.5 Hz, ClCCH]CCl),
7.09 (1H, dd, J1,2 2.6 Hz, J1,3 8.7 Hz, ClC]CHCCl), 6.86 (1H, d, J 9.1 Hz,
HCCH]CO), 4.65 (2H, t,
J
7.4 Hz, NþCH2CH2), 4.49 (2H, s,
OCH2COOꢁ), 1.86 (2H, q, J 7.2 Hz, NþCH2CH2), 1.25 (26H, m,
CH2(CH2)13Me), 0.87 (3H, t, J 6.7 Hz, CH2Me); dC (75 MHz, CDCl3)
172.2, 153.9, 145.1, 144.4, 129.4, 128.2, 127.5, 125.1, 122.6, 114.5, 68.1,
61.9, 31.9, 31.6, 29.69, 29.64, 29.59, 29.4, 29.3, 29.1, 26.1, 22.7, 14.1.
4.2.10. Diallyldimethylammonium
(2,4-dichlorophenoxy)acetate
(N-10). Found: C, 55.32; H, 6.03; N, 4.16. C16H21O3NCl2 requires C,
55.49; H, 6.13; N, 4.05%. nmax (thin film) 3600e3100 (br), 1613,1482,
1424, 1390, 1346, 1283, 1265, 1241, 1106, 1065, 954, 869, 801, 764,
4.2.15. 1-Methyl-3-carbamoylpyridinium (2,4-dichlorophenoxy)ace-
tate (Pyr-2). Found: C, 50.78; H, 3.78; N, 7.96. C15H14O4N2Cl2 re-
quires C, 50.43; H, 3.96; N, 7.84%. nmax (pellet with KBr) 3298, 3131,
1691,1617,1482,1424,1384,1346,1281,1265,1244,1210,1107,1064,
721 cmꢁ1
; dH (300 MHz, D2O) 7.37 (1H, d, J 2.6 Hz, ClCCH]CCl), 7.21
(1H, dd, J1,2 2.6 Hz, J1,3 8.9 Hz, ClC]CHCCl), 6.83 (1H, d, J 8.8 Hz,
HCCH]CO), 6.00 (2H, m, (HaHbC]CHCH2)2Nþ), 5.70 (2H, m,
(HaHbC]CHCH2)2Nþ), 5.63 (2H, m, (HaHbC]CHCH2)2Nþ), 4.50 (2H,
s, OCH2COOꢁ), 3.84 (4H, d, J 7.1 Hz, HaHbC]CHCH2)2Nþ), 2.98 (6H,
s, MeNþMe); dC (75 MHz, D2O) 178.0,155.0,132.3,131.9,130.6,128.1,
126.9, 125.1, 116.9, 70.2, 68.7 (t, J 3.1 Hz), 52.1 (t, J 4.3 Hz).
1043, 801, 764, 635 cmꢁ1 dH (300 MHz, D2O) 9.24 (1H, s, Nþ]
;
CHCC(O)NH2), 8.96 (1H, d, J 6.0 Hz, NþCH]CH), 8.82 (1H, d, J 8.2 Hz,
NþCH]CHCH), 8.14 (1H, t, J 7.3 Hz, NþCH]CHCH), 7.22 (1H, d, J
2.6 Hz, ClCCH]CCl), 7.10 (1H, dd, J1,2 2.6 Hz, J1,3 8.9 Hz, ClC]
CHCCl), 6.77 (1H, d, J 8.8 Hz, HCCH]CO), 4.86 (2H, s, OCH2COOꢁ),
4.49 (3H, s, NþMe); dC (75 MHz, D2O) 178.1,168.0,154.9,150.0,147.8,
146.2, 136.0, 132.2, 130.9, 130.6, 128.0, 125.0, 116.8, 70.2, 51.4.
4.2.11. 1-Methyl-3-octyloxymethylimidazolium (2,4-dichlorophenoxy)
acetate (Im-1). Found: C, 56.71; H, 6.73; N, 6.26. C21H30O4N2Cl2 re-
quires C, 56.62; H, 6.80; N, 6.29%. nmax (liquid film) 3600e3100 (br),
3149, 2925, 2855, 1609, 1481, 1425, 1392, 1346, 1283, 1265, 1241,
4.2.16. 1,1-Dimethylpiperidinium (2,4-dichlorophenoxy)acetate (Pip-
1). Found: C, 53.76; H, 6.59; N, 4.01. C15H21O3NCl2 requires C,
53.89; H, 6.35; N, 4.19%. nmax (thin film) 2999, 2940, 1644, 1608,
1483, 1430, 1347, 1282, 1266, 1243, 1107, 1064, 1043, 868, 801,
1159, 1106, 1064, 868, 801 cmꢁ1
; dH (300 MHz, CDCl3) 10.05 (1H, t, J
1.1 Hz, NCH]Nþ), 7.44 (1H, t, J 1.9 Hz, MeNCH]CHNþ), 7.39 (1H, t, J
1.l9 Hz, CH3NCH]CHNþ), 7.26 (1H, d, J 2.5 Hz, ClCCH]CCl), 7.10 (1H,
dd, J1,2 2.5 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.87 (1H, d, J 8.8 Hz, HCCH]
CO), 5.54 (2H, s, NþCH2O), 4.46 (2H, s, OCH2COOꢁ), 4.19 (3H, s, MeN),
3.40 (2H, t, J 6.5 Hz, OCH2CH2), 1.48 (2H, q, J 6.3 Hz, OCH2CH2), 1.22
(10H, m, CH2(CH2)5CH3), 0.87 (3H, t, J 6.9 Hz, CH2Me); dC (75 MHz,
CDCl3) 172.3,153.1,138.1,129.2,127.3,124.7,123.6,122.4,120.6,114.3,
78.8, 70.2, 68.6, 36.2, 31.7, 29.3, 29.2, 29.1, 25.8, 22.5, 14.0.
766 cmꢁ1
; dH (300 MHz, DMSO-d6) 7.46 (1H, d, J 2.6 Hz, ClCCH]
CCl), 7.26 (1H, dd, J1,2 2.6 Hz, J1,3 8.8 Hz, ClC]CHCCl), 6.83 (1H, d, J
8.9 Hz, HCCH]CO), 4.22 (2H, s, OCH2COOꢁ), 3.33 (4H, t, J 5.8 Hz,
CH2CH2NþCH2CH2), 3.07 (6H, s, MeNþMe), 1.73 (4H, q, J 5.2 Hz,
CH2CH2NþCH2CH2), 1.48 (2H, q,
J
5.9 Hz, NþCH2CH2CH2); dC
(75 MHz, DMSO-d6) 168.7, 153.8, 128.7, 127.5, 122.9, 121.6, 115.0,
68.7, 61.4, 50.7, 20.5, 19.6.
4.2.17. 1-Propoxymethyl-1-methylpiperidinium (2,4-dichlorophenoxy)
acetate (Pip-2). Found: C, 57.51; H, 7.82; N, 3.58. C18H29O3NCl2 re-
quires C, 57.13; H, 7.74; N, 3.70%. nmax (liquid film) 3600e3100 (br),
4.2.12. 1-Methyl-3-octyltiomethylimidazolium (2,4-dichlorophenoxy)
acetate (Im-2). Found: C, 64.81; H, 10.26; N, 11.49. C21H30O3N2SCl2

4272
J. Pernak et al. / Tetrahedron 68 (2012) 4267e4273
2965, 1612,1482, 1391, 1346, 1283, 1266, 1240, 1185, 1123, 1106, 1065,
1040, 869, 838, 801, 764 cmꢁ1
dH (300 MHz, D2O) 7.36 (1H, d, J
4.4. Herbicidal activity
;
2.6 Hz, ClCCH]CCl), 7.21 (1H, dd, J1,2 2.6 Hz, J1,3 8.9 Hz, ClC]CHCCl),
6.85 (1H, d, J 9.0 Hz, HCCH]CO), 4.62 (2H, s, OCH2COOꢁ), 4.50 (2H, s,
NþCH2O), 3.76 (2H, t, J 6.5 Hz, OCH2CH2), 3.25 (4H, t, J 7.0 Hz,
CH2CH2NþCH2CH2), 2.97 (3H, s, NþMe), 1.84 (2H, m, NþCH2CH2CH2),
1.83 (2H, m, OCH2CH2), 1.61 (4H, q, J 7.0 Hz, CH2CH2NþCH2CH2), 0.91
(3H, t, J 7.4 Hz, CH2Me); dC (75 MHz, D2O) 177.7, 155.2, 132.2, 130.6,
128.1, 125.2, 117.1, 93.6, 78.6, 70.3, 60.1, 47.4, 25.1, 23.4, 21.8, 12.3.
Prepared ILs were tested in field experiments performed in
2009e2010 at Experimental Station in Winna Gora (Poland) on fal-
low land and in spring barley. Plot size was 16 m2. The experimental
design was a randomized block with four replications. All treatments
were applied using a small plot spraying equipment with XR 11003
flat-fan nozzle with a water volume of 200 L haꢁ1 and an operating
pressure of 0.3 MPa. The standard products were herbicides con-
taining 2,4-D as sodium salt (Pielik 85 SPd85% 2,4-D), dimethy-
lammonium salt (Aminopielik Standard 600 SLd600 g 2,4-D per 1 L)
and as 2-ethylhexyl ester (Esteron 460 ECd460 g 2,4-D per 1 L).
Weed control was evaluated visually using a scale of 0 (no
control) to 100% (complete weed destruction).
4.2.18. 1-Pentyloxymethyl-1-methylpiperidinium(2,4-dichlorophenoxy)
acetate (Pip-3). Found: C, 59.68; H, 8.31; N, 3.60. C20H33O3NCl2
requires C, 60.00; H, 8.20; N, 3.45%. nmax (liquid film) 3600e3100
(br), 2955, 2871, 1611, 1482, 1391, 1346, 1283, 1266, 1241, 1106,
1065, 1043, 869, 801, 764, 722 cmꢁ1
; dH (300 MHz, D2O) 7.25 (1H,
d, J 2.5 Hz, ClCCH]CCl), 7.17 (1H, dd, J1,2 2.5 Hz, J1,3 8.9 Hz, ClC]
CHCCl), 6.86 (1H, d, J 8.9 Hz, HCCH]CO), 4.54 (2H, s, OCH2COOꢁ),
4.45 (2H, s, NþCH2O), 3.66 (2H, t, J 6.7 Hz, OCH2CH2), 3.19 (4H, t, J
7.0 Hz, CH2CH2NþCH2CH2), 2.92 (3H, s, NþMe), 1.78 (2H, m,
NþCH2CH2CH2), 1.76 (4H, m, CH2CH2NþCH2CH2), 1.50 (2H, q,
J 7.0 Hz, OCH2CH2), 1.23 (4H, m, CH2CH2CH3), 0.85 (3H, t, J 6.8 Hz,
CH2Me); dC (75 MHz, D2O) 176.9, 155.2, 131.8, 130.2, 127.6,
124.9, 117.0, 93.0, 76.3, 70.1, 59.8, 47.2, 31.3, 30.0, 24.5, 23.1, 21.6,
16.0.
4.5. Surface activity
Surface tension measurements were carried out by the use of
a DSA 100 analyzer (Kruss, Germany, accuracy ꢂ0.01 mN mꢁ1), at
€
25 ꢀC. The surface tension was determined using the shape drop
method. Basically, the principle of this method is to form an axi-
symmetric drop at the tip of a needle of a syringe. The image of the
drop (3
tension (
m
g
L) is taken from a CCD camera and digitized. The surface
in mN mꢁ1) is calculated by analyzing the profile of the
drop according to the Laplace equation. Temperature was con-
trolled using a Fisherbrand FBH604 thermostatic bath (Fisher,
Germany, accuracy ꢂ0.1 ꢀC). The values of the critical micelle con-
centration (CMC) and the surface tension at the CMC (gCMC) were
determined from the intersection of the two straight lines drawn in
low and high concentration regions in surface tension curves
4.2.19. 4-Butyl-4-methylmorpholinium (2,4-dichlorophenoxy)acetate
(Mor-1). Found: C, 53.57; H, 6.82; N, 3.89. C17H25O4N2Cl2 requires
C, 53.87; H, 6.67; N, 3.70%. nmax (thin film) 3600e3100 (br), 2964,
2875, 1644, 1608, 1483, 1430, 1347, 1282, 1267, 1243, 1107, 1064,
1044, 898, 868, 801, 764 cmꢁ1
; dH (300 MHz, DMSO-d6) 7.47 (1H, d,
J 2.7 Hz, ClCCH]CCl), 7.26 (1H, dd, J1,2 2.7 Hz, J1,3 9.0 Hz, ClC]
CHCCl), 6.84 (1H, d, J 9.0 Hz, HCCH]CO), 4.25 (2H, s, OCH2COOꢁ),
3.89 (4H, t, J 5.8 Hz, CH2CH2OCH2CH2), 3.71 (2H, t, J 4.4 Hz,
NþCH2CH2), 3.43 (4H, t, J 4.7 Hz, CH2CH2OCH2CH2), 3.14 (3H, s,
MeNþ), 1.65 (2H, q, J 4.0 Hz, NþCH2CH2CH2), 1.30 (2H, sex, J 7.3 Hz,
CH2CH2Me), 0.92 (3H, t, J 7.2 Hz, CH2Me); dC (75 MHz, DMSO-d6)
168.7, 153.8, 128.7, 127.5, 123.0, 121.7, 115.0, 68.5, 63.6, 59.9, 58.9,
45.9, 22.7, 19.2, 13.5.
(gelog C curves) using a linear regression analysis method.
Acknowledgements
This work was supported by grant No. 7548/B/H03/2011/40
(National Science Centre, Poland).
Supplementary data
4.2.20. 1-Butyl-1-methylpyrrolidinium (2,4-dichlorophenoxy)-ace-
tate (Pyrr-1). Found: C, 56.55; H, 6.82; N, 3.77. C17H25O3NCl2
requires C, 56.35; H, 6.97; N, 3.87%. nmax (liquid film) 3600e3100
(br), 2963, 1613, 1483, 1424, 1346, 1282, 1266, 1244, 1107, 1064,
This material include the physicochemical data of 2,4-D-imi-
dazolium (Im), 2,4-D-pyridinium (Pyr), 2,4-D-piperidinium (Pip),
2,4-D-morpholinium (Mor), and 2,4-D-pyrrolidinium (Pyrr) salts,
as well as description of HILs as solvents in DielseAlder reaction.
Supplementary data associated with this article can be found in the
online version, at doi:10.1016/j.tet.2012.03.065.
1043, 801, 763 cmꢁ1
; dH (300 MHz, DMSO-d6) 7.47 (1H, d, J 2.5 Hz,
ClCCH]CCl), 7.26 (1H, dd, J1,2 2.5 Hz, J1,3 8.8 Hz, ClC]CHCCl),
6.83 (1H, d, J 9.0 Hz, HCCH]CO), 4.21 (2H, s, OCH2COOꢁ), 3.47
(4H, m, CH2CH2CH2CH2), 3.30 (2H, t, J 8.4 Hz, NþCH2CH2CH2Me),
2.98 (3H, s, CH3Nþ), 2.07 (4H, m, CH2CH2CH2CH2), 1.66 (2H, q,
J 4.1 Hz, NþCH2CH2CH2Me), 1.30 (2H, sex, J 7.4 Hz, CH2CH2CH3),
0.92 (3H, t, J 7.3 Hz, CH2Me); dC (75 MHz, DMSO-d6) 168.9, 153.9,
128.8, 127.6, 123.0, 121.7, 115.1, 68.7, 63.4, 62.9, 47.4, 25.0, 21.1,
19.4, 13.6.
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