Synthesis and herbicidal activity of 3-aryl-1-[2-(aryloxy)propanoyl] imidazolidine-2,4-diones

Article abstract of DOI:10.1002/jhet.114

(Chemical Equation Presented) A series of novel 3-aryl-1-[2-(aryloxy) propanoyl]imidazolidine-2,4-diones were synthesized by the condensation of 3-aryl-imidazolidine-2,4-diones with 2-(aryloxy)propanoyl chlorides under mild conditions. Their structures we

Full text of DOI:10.1002/jhet.114

544
Synthesis and Herbicidal Activity of 3-Aryl-1-[2-
(aryloxy)propanoyl]imidazolidine-2,4-diones
Vol 46
Ke Li and De-Qing Shi*
Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of
Chemistry, Central China Normal University, Wuhan 430079, Hubei, People’s Republic of China
*E-mail: chshidq@mail.ccnu.edu.cn
Received May 21, 2008
DOI 10.1002/jhet.114
Published online 5 May 2009 in Wiley InterScience (www.interscience.wiley.com).
A series of novel 3-aryl-1-[2-(aryloxy)propanoyl]imidazolidine-2,4-diones were synthesized by the
condensation of 3-aryl-imidazolidine-2,4-diones with 2-(aryloxy)propanoyl chlorides under mild condi-
1
tions. Their structures were confirmed by IR, H NMR, mass spectroscopy, and elemental analyses. The
preliminary bioassay indicated that the target compounds II displayed excellent herbicidal activity
against monocotyledonous (barnyard grass) and dicotyledonous (oil rape) plants.
J. Heterocyclic Chem., 46, 544 (2009).
INTRODUCTION
propanoyl chlorides under mild conditions to give the
target compounds II in good yields (73–90%).
Their structures of the products were confirmed by
Recently, imidazolidine-2,4-dione derivatives have
attracted the interest of chemists because some of them
exhibit wide range of pharmaceutical activity such as
anti-HIV [1], microbicidal activity [2], or nonpeptide
inhibitors of human heart chymase [3] as well as agro-
chemical activity such as herbicidal [4] and fungicidal
activity [5]. In the area of modern crop protection, am-
ide derivatives are widely used as bactericides [6] and
fungicides [7]. Especially, some of the amide derivatives
are found to be an inhibitor of photosystem II electron
transport and used as a very important class of herbi-
cides in the world agrochemical market, there are about
57 amide herbicides; acetochlor, metolachlor, and buta-
chlor are the best selling amide herbicides in the world
[8,9]. As a continuation of our ongoing project aimed at
investigating novel biologically nitrogen-containing het-
erocyclic compounds [10,11], we designed and synthe-
sized a series of novel 3-aryl-1-[2-(aryloxy)propanoyl]
imidazolidine-2,4-diones, which have both imidazoline-
2,4-dione and 2-(aryloxy)propanoyl moieties. Herein, we
would like to report the synthesis and biological activity
of the title compounds II (Scheme 1).
1
IR, H NMR, mass spectroscopy, and elemental analy-
ses. The structures of compounds II were deduced from
their spectroscopic data. In the H NMR spectra of com-
1
pounds II, the two methylene protons display two dou-
blets because of their different magnetic environments
with the coupling constant of 18 Hz, whereas the two
methylene protons in compounds I appear as a singlet at
d 4.1. The IR spectra of compounds II showed normal
stretching absorption bands indicating the existence of
the C¼¼O, Ar group, and CAOAC moiety. The EI mass
spectra of compounds II revealed the existence of their
molecular ion peaks and main fragmentation peaks,
which were in accordance with the given structures of
products II.
Herbicidal activity. The herbicidal activity values of
the title compounds II against Brassica campestris (oil
rape) and Echinochloa crus-galli (barnyard grass) has
been investigated at the dosages of 100 mg/L and 10
mg/L compared with distilled water and the commer-
cially available herbicide, 2,4-dichlorophenoxyacetic
acid (2,4-D) according to the method described in the
Experimental section. The preliminary results of bioas-
say showed that compounds II possessed excellent her-
bicidal activity. The activity data were listed in Table 1.
For example, compounds IIh and IIj exhibited as good
herbicidal activity as the commercially available herbi-
cide 2,4-D. Further structure-activity relationships are
under investigation.
RESULTS AND DISCUSSION
3-Aryl-imidazolidine-2,4-diones (I) were prepared
from the reaction of aromatic isocyanates with a-amino
acids in a basic medium according to the reported
method. Compound I reacted with various 2-(aryloxy)-
C
V
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Synthesis and Herbicidal Activity of
3-Aryl-1-[2-(aryloxy)propanoyl]imidazolidine-2,4-diones
545
Scheme 1. Synthetic route to compounds II.
General procedure for the preparation of 3-aryl-1-[2-
(aryloxy)propanoyl]imidazolidine-2,4-diones II. To the solu-
tion of 3-aryl-imidazolidine-2,4-dione (3 mmol) and triethyl
amine (6 mmol) in dry CH2Cl2 (15 mL) was added dropwise
the solution of 2-(aryloxy)propanoyl chloride (3 mmol) in dry
CH2Cl2 (10 mL) while cooling in an ice-bath, after the addi-
tion, the mixture was stirred at room temperature for 3–4 h
(monitored by TLC). The workup involved stripping the sol-
vent followed by an addition of water and extraction of the
product mixture into CH2Cl2. After phase separation, washing
by aqueous sodium hydrogen carbonate, drying over anhydrous
sodium sulfate, filtration and evaporation, the crude product
was purified by flash column chromatography on silica gel
using petroleum ether and ethyl acetate (3:1---1:1, v/v) as the
eluent to give white crystals (IIa~IIl).
In conclusion, a series of novel 3-aryl-1-[2-(aryloxy)-
propanoyl]imidazolidine-2,4-diones were synthesized by
the condensation of 3-arylimidazolidine-2,4-diones with
2-[aryloxy]propanoyl chlorides under mild conditions.
The preliminary bioassay indicated that the target com-
pounds II displayed excellent herbicidal activity against
monocotyledonous (barnyard grass) and dicotyledonous
(oil rape) plants.
EXPERIMENTAL
Melting points were determined with a WRS-1B digital
1
melting point apparatus and are uncorrected. H NMR spectra
1-(2-Phenoxypropanoyl)-3-phenylimidazolidine-2,4-dione
1
(IIa). Yield: 75%, mp 56.2–57.8ꢀC; H NMR (CDCl3): d 1.70
were recorded with a Varian Mercury PLUS400 (400 MHz)
spectrometer with TMS as the internal reference and CDCl3 as
the solvent, whereas mass spectra were obtained with a Finni-
gan TRACEMS2000 spectrometer using the EI method. IR
spectra were measured by a Nicolet NEXUS470 spectrometer.
Elemental analyses were performed with an Elementar Vario
ELIII CHNSO elemental analyzer. All of the solvents and
materials were reagent grade and purified as required. 2-(Ary-
loxy)propanoyl chlorides and 3-aryl-imidazolidine-2,4-diones
were prepared according to the methods described in referen-
ces [12] and [13–16], respectively.
(d, J ¼ 6.8 Hz, 3H, CH3), 4.57 (dd, J ¼ 18.4 Hz, 2H, CH2N),
5.95 (q, J ¼ 6.4 Hz, 1H, CH), 6.90–7.00 (m, 3H, ArAH),
7.28–7.30 (m, 2H, ArAH), 7.40–7.55 (m, 5H, ArAH); IR:
C¼¼O 1786, 1738, 1725, Ar 1592, 1484, 1445, ArAOAC
1040, CACl 756 cmꢁ1; ms: m/z 324 (Mþ, 16), 247 (23.9), 231
(100), 122 (35.2), 121 (90.2), 105 (15.9), 93 (35.5), 77 (85.6).
Anal. Calcd. for C18H16N2O4: C, 66.66; H, 4.97; N, 8.64.
Found: C, 66.42; H, 5.13; N, 8.79.
3-(4-Fluorophenyl)-1-(2-phenoxypropanoyl)imidazolidine-
2,4-dione (IIb). Yield: 73%, mp 56.8–58.2ꢀC; 1H NMR
(CDCl3): d 1.71 (d, J ¼ 6.8 Hz, 3H, CH3), 4.47 (dd, J ¼ 18.8
Hz, 2H, CH2N), 5.92 (q, J ¼ 6.8 Hz, 1H, CH); 6.90 (d, 2H, J
¼ 7.6 Hz, ArAH), 6.97 (q, 1H, J ¼ 7.6 Hz, ArAH), 7.25–7.30
(m, 2H, ArAH), 7.37–7.42 (m, 2H, ArAH), 7.48–7.51 (m, 2H,
ArAH); IR: C¼¼O 1784, 1739, 1727, Ar 1587, 1489, 1425,
ArAOAC 1078, CACl 760 cmꢁ1; ms: m/z 344 (10.1), 342
(Mþ, 32), 267 (40.6), 265 (100), 223 (15.5), 153 (27.2), 122
(78.1), 121 (78.1), 105 (15.9), 93 (24.9), 77 (70.2). Anal.
Calcd. for C18H15FN2O4: C, 63.15; H, 4.42; N, 8.18. Found:
C, 63.37; H, 4.60; N, 8.05.
Table 1
The herbicidal activity of compounds II (inhibitory rate %)
Relative inhibition (root %/stalk %)
Oil rape
Barnyard grass
Compd.
100 mg/L
10 mg/L
100 mg/L
10 mg/L
3-(4-Chlorophenyl)-1-(2-phenoxypropanoyl)imidazolidine-
2,4-dione (IIc). Yield: 78%, mp 66.8–68.4ꢀC; 1H NMR
(CDCl3): d 1.69 (d, J ¼ 7.2 Hz, 3H, CH3), 4.45 (dd, J ¼ 18.8
Hz, 2H, CH2N), 5.93 (q, J ¼ 6.4 Hz, 1H, CH); 6.90 (d, 2H, J
¼ 7.6 Hz, ArAH), 6.97 (q, 1H, J ¼ 7.6 Hz, ArAH), 7.17–7.29
(m, 4H, ArAH), 7.37–7.41 (m, 2H, ArAH); IR: C¼¼O 1756,
ms: m/z 360 (7.5), 358 (Mþ, 22.5), 281 (27.7), 238 (100), 122
(65.0), 121 (88.1), 105 (12.8), 93 (38.7), 77 (65.3). Anal.
Calcd. for C18H15ClN2O4: C, 60.26; H, 4.21; N, 7.81. Found:
C, 60.33; H, 4.49; N, 7.92.
IIa
IIb
IIc
IId
IIe
IIf
IIg
IIh
IIi
99.0/93.0
98.1/93.0
99.0/93.0
100/95.3
99.0/95.3
99.3/95.5
99.0/93.0
100/97.7
100/97.7
100/95.3
99.0/95.3
99.0/95.3
99.0/91.5
94.3/74.4
97.1/83.7
97.1/86.0
99.0/86.0
98.1/86.0
97.1/86.0
98.1/88.4
99.0/81.4
98.1/86.0
98.1/83.7
98.1/83.7
98.1/86.0
98.2/91.2
97.5/33.3
97.5/23.8
100./88.0
97.5/83.3
97.5/64.3
97.5/65.3
100./52.4
97.5/78.6
97.5/59.5
100./90.5
97.5/54.8
100./95.0
97.5/33.5
75.0/23.0
90.0/4.8
95.0/73.8
95.0/78.6
97.5/31.0
92.5/38.0
97.5/52.4
97.5/64.3
95.0/52.4
97.5/33.3
97.5/50.0
97.5/61.9
97.5/31.2
1725, Ar 1578, 1494, 1482, ArAOAC 1050, CACl 759 cmꢁ1
;
IIj
IIk
IIl
1-[2-(2,4-Dichlorophenoxy)propanoyl]-3-phenylimidazolidine-
2,4-dione (IId). Yield: 81%, mp 52.6–54.2ꢀC; 1H NMR
2,4-D
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

546
K. Li and D.-Q. Shi
Vol 46
(CDCl3): d 1.59 (d, J ¼ 6.8 Hz, 3H, CH3), 4.63 (dd, J ¼ 18.8
Hz, 2H, CH2N), 5.86 (q, J ¼ 6.8 Hz, 1H, CH); 6.88–7.33 (m,
8H, ArAH); IR: C¼¼O 1800, 1746, 1725, Ar 1585, 1488,
1440, ArAOAC 1022, CACl 760 cmꢁ1; ms: m/z 394 (16.2),
393 (5.1), 392 (Mþ, 25.0), 315 (100), 122 (45.4), 121 (62.6),
105 (19.5), 93 (53.8), 77 (25.2). Anal. Calcd. for
C18H14Cl2N2O4: C, 54.98; H, 3.59; N, 7.12. Found: C, 54.83;
H, 3.47; N, 6.95.
1-[2-(2,4-Dichlorophenoxy)propanoyl]-3-(4-fluorophenyl)-
imidazolidine-2,4-dione (IIe). Yield: 76%, mp 54.2–55.4ꢀC;
1H NMR (CDCl3): d 1.74 (d, J ¼ 6.8 Hz, 3H, CH3), 4.50 (dd,
J ¼18.4 Hz, 2H, CH2N), 5.86 (q, J ¼ 6.8 Hz, 1H, CH); 6.85
(d, 1H, J ¼ 8.8 Hz, ArAH), 7.14 (d, 1H, J ¼ 8.4 Hz, ArAH),
7.33–7.40 (m, 3H, ArAH), 7.48 (d, 2H, J ¼ 8.4 Hz, ArAH).
IR: C¼¼O 1787, 1740, 1724, Ar 1596, 1487, 1436, ArAOAC
1076, CACl 748 cmꢁ1; ms: m/z 412 (5.2), 410 (Mþ, 26.5),
317 (23.8), 300 (100), 111 (58.2), 95 (62.0). Anal. Calcd. for
C18H13Cl2FN2O4: C, 52.57; H, 3.19; N, 6.81. Found: C, 52.69;
H, 3.33; N, 6.57.
3-(4-Chlorophenyl)-1-[2-(2,4-dichlorophenoxy)propanoyl]
imidazolidine-2,4-dione (IIf). Yield: 87%, mp 54.2–55.4ꢀC;
1H NMR (CDCl3): d 1.74 (d, J ¼ 6.8 Hz, 3H, CH3), 4.92 (dd,
J ¼ 18.4 Hz, 2H, CH2N), 5.84 (q, J ¼ 6.4 Hz, 1H, CH); 6.84
(d, 1H, J ¼ 8.0 Hz, ArAH), 7.13 (q, 1H, J ¼ 7.6 Hz, ArAH),
7.19 (d, 2H, J ¼ 8.0 Hz, ArAH), 7.38 (d, 1H, J ¼ 7.6 Hz,
ArAH), 7.40 (d, 2H, J ¼ 8.0 Hz, ArAH); IR: C¼¼O 1803,
1740, 1728, Ar 1594, 1496, 1485, ArAOAC 1020, CACl 746
cmꢁ1; ms: m/z 430 (2.9), 428 (11.2), 426 (Mþ, 13.3), 268
(29.3), 267 (14.6), 265 (100), 237 (3.2), 223 (8.4), 211 (10.7),
189 (6.2), 161 (4.7), 153 (8.6), 125 (6.5), 109 (2.3), 56 (4.1).
Anal. Calcd. for C18H13Cl3N2O4: C, 50.55; H, 3.06; N, 6.55.
Found: C, 50.41; H, 2.94; N, 6.34.
127 (58.6), 111 (24.2). Anal. Calcd. for C18H14Cl2N2O4: C,
54.98; H, 3.59; N, 7.12. Found: C, 54.83; H, 3.71; N, 7.21.
1-[2-(4-Fluorophenoxy)propanoyl]-3-phenylimidazolidine-2,
4-dione (IIj). Yield: 85%, mp 64.2–65.5ꢀC; 1H NMR
(CDCl3): d 1.67 (d, J ¼ 6.8 Hz, 3H, CH3), 4.47 (dd, J ¼ 18.8
Hz, 2H, CH2N), 5.85 (q, J ¼ 6.4 Hz, 1H, CH); 6.85–6.98 (m,
4H, ArAH), 7.38–7.54 (m, 5H, ArAH); IR: C¼¼O 1738, 1716,
Ar 1599, 1504, 1436, CH3 1402, CAF 1262, 1201, ArAOAC
1095; ms: m/z 358 (Mþ, 3.1), 267 (21.8), 265 (100), 238
(10.5), 210 (45.0), 122 (30.2), 121 (56.9), 105 (9.0), 93 (41.0),
77 (25.2). Anal. Calcd. for C18H15FN2O4: C, 63.15; H, 4.42;
N, 8.18. Found: C, 63.30; H, 4.67; N, 7.95.
1-[2-(4-Fluorophenoxy)propanoyl]-3-(4-fluorophenyl)imida-
zolidine-2,4-dione (IIk). Yield: 82%, mp 162.2–163.8ꢀC; 1H
NMR (CDCl3): d 1.68 (d, J ¼ 6.8 Hz, 3H, CH3), 4.50 (dd, J
¼ 18.8 Hz, 2H, CH2N), 5.84 (q, J ¼ 6.8 Hz, 1H, CH); 6.86–
6.89 (m, 2H, ArAH), 6.95–6.99 (m, 2H, ArAH), 7.38 (d, 2H,
J ¼ 8.8 Hz, ArAH), 7.50 (d, 2H, J ¼ 8.8 Hz, ArAH); IR:
C¼¼O 1787, 1739, 1720, Ar 1576, 1514, 1462, ArAOAC
1060, CACl 765 cmꢁ1; ms: m/z 362 (2.0), 360 (Mþ, 4.3), 267
(41.7), 265 (100), 223 (10.2, 211 (13.6), 153 (8.8), 139 (21.4),
125 (4.9), 111 (9.8), 95 (10.2). Anal. Calcd. for
C18H14F2N2O4: C, 60.00; H, 3.92; N, 7.77. Found: C, 59.81;
H, 3.75; N, 7.64.
3-(4-chlorophenyl)-1-[2-(4-fluorophenoxy)propanoyl]imida-
zolidine-2,4-dione (IIl). Yield: 82%, mp 66.8–68.4ꢀC; 1H
NMR (CDCl3): d 1.67 (d, J ¼ 6.8 Hz, 3H, CH3), 4.48 (dd, J
¼ 18.4 Hz, 2H, CH2N), 5.85 (q, J ¼ 6.8 Hz, 1H, CH); 6.86–
6.99 (m, 4H, ArAH), 7.29–7.51 (m, 4H, ArAH); IR: C¼¼O
1785, 1740, 1722, Ar 1586, 1494, 1463, ArAOAC 1074,
CACl 758 cmꢁ1; ms: m/z 379 (5.9), 378 (5.8), 376 (Mþ,
28.1), 269 (4.4), 267 (40.9), 266 (62.7), 265 (100), 237 (8.2),
223 (13.6), 211 (19.4), 153 (30.4), 140 (44.7), 139 (66.5), 125
(15.7), 111 (37.3), 95 (46.9), 83 (24.3), 56 (53.2). Anal. Calcd.
for C18H14ClFN2O4: C, 57.38; H, 3.75; N, 7.44. Found: C,
57.14; H, 3.83; N, 7.60.
Bioassay method. Herbicidal activity testing. Herbicidal
testing of the newly synthesized compounds II was carried
out in a greenhouse, with temperature 23 ꢂ 1ꢀC, relative hu-
midity (RH) 60 ꢂ 5%, light intensity 10 Klux, photoperiod 8
h/day. Twenty seeds of each weed species including oil rape
and barnyard grass were chosen for testing. Seedlings were
grown in the test plate of 9-cm diameter containing two
pieces of filter paper and 9 mL solution of the tested com-
pound (100 mg/L and 10 mg/L, respectively). Distilled water
and 2,4-D were used as the comparison compounds. The her-
bicidal activity was assessed as the inhibitory rate in compar-
ison with the distilled water. The herbicidal rating score was
based on visual observation. Range from 0 to 100%, 0%
means no effect and 100% means complete killing. The test
was run three times, and the results were averaged and given
as activity in Table 1.
1-[2-(4-Chlorophenoxy)propanoyl]-3-phenylimidazolidine-2,
1
4-dione (IIg). Yield: 86%, mp 74.7–75.5ꢀC; H NMR (CDCl3):
d 1.69 (d, J ¼ 6.8 Hz, 3H, CH3), 4.50 (dd, J ¼ 18.4 Hz, 2H,
CH2N), 5.92 (q, J ¼ 6.8 Hz, 1H, CH); 6.84 (d, 2H, J ¼ 7.6 Hz,
ArAH), 7.23 (d, 2H, J ¼ 7.6 Hz, ArAH), 7.41–7.54 (m, 5H,
ArAH); IR: C¼¼O 1741, 1726, Ar 1597, 1490, CH3 1403,
ArAOAC 1046, CACl 762 cmꢁ1; ms: m/z 360 (4.2), 358 (Mþ,
12.1), 267 (12.4), 265 (100), 237 (36.8), 209 (52.3), 105 (9.3),
93 (52.5), 77 (36.0). Anal. Calcd. for C18H15ClN2O4: C, 60.26;
H, 4.21; N, 7.81. Found: C, 60.05; H, 4.14; N, 7.60.
1-[2-(4-Chlorophenoxy)propanoyl]-3-(4-fluorophenyl)imida-
zolidine-2,4-dione (IIh). Yield: 90%, mp 147.8–149.0ꢀC; 1H
NMR (CDCl3): d 1.69 (d, J ¼ 6.8 Hz, 3H, CH3), 4.47 (dd, J
¼ 18.4 Hz, 2H, CH2N), 5.86 (q, J ¼ 6.8 Hz, 1H, CH); 6.84
(d, 2H, J ¼ 8.0 Hz, ArAH), 7.20–7.24 (m, 2H, ArAH), 7.35–
7.38 (m, 2H, ArAH), 7.47–7.50 (m, 2H, ArAH); IR: C¼¼O
1741, 1713, Ar 1500, 1488, CH3 1386, CAF 1267, ArAOAC
1090, CACl 821 cmꢁ1; ms: m/z 378 (2.5), 376 (Mþ, 16.3),
237 (82.3), 210 (100), 139 (24.6), 112 (68.2), 96 (70.2). Anal.
Calcd. for C18H14ClFN2O4: C, 57.38; H, 3.75; N, 7.44. Found:
C, 57.47; H, 3.70; N, 7.61.
1-[2-(4-Chlorophenoxy)propanoyl]-3-(4-chlorophenyl)imida
zolidine-2,4-dione (IIi). Yield: 83%, mp 74.7–75.5ꢀC; 1H
NMR (CDCl3): d 1.69 (d, J ¼ 6.8 Hz, 3H, CH3), 4.46 (dd, J ¼
18.4 Hz, 2H, CH2N), 5.87 (q, J ¼ 6.8 Hz, 1H, CH); 6.82–6.86
(m, 2H, ArAH), 7.19–7.25 (m, 4H, ArAH), 7.37–7.41 (m, 2H,
ArAH); IR: C¼¼O 1801, 1737, 1730, Ar 1585, 1494, 1481,
ArAOAC 1022, CACl 760 cmꢁ1; ms: m/z 394 (4.8), 392 (Mþ,
24.1), 267 (25.1), 265 (100), 237 (65.4), 209 (38.6), 183 (4.9),
Acknowledgments. This work was supported by the Natural
Science Foundation of China (Grant numbers: 20302002,
20872046), and the Scientific Research Foundation for the
Returned Overseas Chinese Scholars, Ministry of Education of
China (Grant number: [2007] 1108).
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DOI 10.1002/jhet

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547
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