Synthesis and Biological Activity Evaluation of Novel α-Amino Phosphonate Derivatives Containing a Pyrimidinyl Moiety as Potential Herbicidal Agents

Article abstract of DOI:10.1021/acs.jafc.5b02335

To find novel high-activity and low-toxicity herbicide lead compounds with novel herbicidal mode of action, series of novel α-amino phosphonate derivatives containing a pyrimidinyl moiety, I, II, III, and IV, were designed and synthesized by Lewis acid (m

Full text of DOI:10.1021/acs.jafc.5b02335

Article
pubs.acs.org/JAFC
Synthesis and Biological Activity Evaluation of Novel
α‑Amino Phosphonate Derivatives Containing
a Pyrimidinyl Moiety as Potential Herbicidal Agents
Jin-Long Chen,† Wu Tang,† Jian-Yi Che,† Kai Chen,† Gang Yan,† Yu-Cheng Gu,§ 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
§Syngenta Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, United Kingdom
S
* Supporting Information
ABSTRACT: To find novel high-activity and low-toxicity herbicide lead compounds with novel herbicidal mode of action, series
of novel α-amino phosphonate derivatives containing a pyrimidinyl moiety, I, II, III, and IV, were designed and synthesized by
Lewis acid (magnesium perchlorate) catalyzed Mannich-type reaction of aldehydes, amines, and phosphites. Their structures
1
were clearly identified by spectroscopy data (IR, H NMR, 31P NMR, EI-MS) and elemental analyses. The bioassay [in vitro,
in vivo (GH1 and GH2)] showed that most compounds I exhibited good herbicidal activities; for example, the activities of
compounds Ib, Ic, Ig, Ii, Ik, and Im were as good as the positive control herbicides (acetochlor, atrazine, mesotrione, and
glyphosate). However, their structural isomers II and III and analogues IV did not display any herbicidal activities in vivo,
although some of them possessed selective inhibitory activity against Arabidopsis thaliana in vitro. Interestingly, it was found that
compounds IVs, IVt, and IVl showed selective insecticidal activities against Aphis species or Plutella xylostella, respectively. Their
preliminary herbicidal mode of action and structure−activity relationships were also studied.
KEYWORDS: pyrimidine, α-amino phosphonate, herbicidal activity, insecticidal activity
O,O′-diethyl N-(4-methylbenzothiazol-2-yl) 1-amino-1-(2-
fluorophenyl)methylphosphonate (Dufulin, Figure 1) is a com-
mercial plant anti-TMV (tobacco mosaic virus) agent.19,20
It should be mentioned that some aminomethylenebisphos-
phonic acid derivatives were evaluated as potential inhibitors of
plant δ1-pyrroline-5-carboxylate reductase (EC 1.5.1.2), which
catalyzes the last step in proline biosynthesis and can probably
be functionalized as a novel potential herbicide target
enzyme.21,22 On the other hand, since the late 1990s,
pyrimidinyl carboxylic acid derivatives with notable herbicidal
activities, known as inhibitors of branched-chain amino acids
(ALS or AHAS) synthase, have attracted increasing attention of
pesticide scientists.23−27 To date, several pyrimidyl carboxylic
acid derivatives such as bispyribac-sodium and pyriminobac-
methyl have been commercialized as herbicides (Figure 1).
Furthermore, one of the pyrimidyl benzylamine derivatives,
Pyribambenz propyl, has also been commercialized re-
cently.28−30 Bioisosterism is an effective approach for
developing and optimizing bioactive lead compounds, and
nitenpyram, acetamiprid, and thiacloprid are some successful
cases.31 The preliminary herbicidal evaluation of a series of
α-amino alkyl phosphonates containing a pyrimidinyl moiety
was reported recently by our group;32 to evaluate further their
herbicidal activity and study their structure−activity relation-
ship as well as the mode of action, we designed and synthesized
INTRODUCTION
■
Phosphorus-containing compounds have received continuous
attention due to their versatile biological activities and are
widely used as pharmaceuticals and agrochemicals such as
insecticides, fungicides, or plant growth regulators.1−3 More-
over, some phosphorus-containing compounds act as high-
efficiency ligands in transition metal-catalyzed asymmetric
reactions.4,5 Phosphonates possess more lipophilic nature and
cell permeability along with physiological stability because the
phosphorus−carbon bond is not susceptible to enzymatic
degradation by phosphatases.6,7 α-Amino phosphonic acid and
its ester derivatives are the bioisosteres of natural amino acid.
When the carboxylic group is replaced by a phosphonic moiety,
they resemble the tetrahedral transition state of several
enzymatic reactions, particularly amide bond formation and
hydrolysis; however, they are significant differences such as
molecular dimension, group shape (flat CO2H vs tetrahedral
PO3H2), and acidity between amino acids and phosphonic
counterparts. Therefore, several enzymes are unable to
discriminate between carboxylic and phosphonic function
with regard to binding to active sites. The structural antagonism
between amino acids and the phosphonic counterparts results
in inhibition of enzyme activity.8,9 Therefore, α-amino
phosphonic acid and its ester derivatives play a vital role in
medicinal chemistry and pesticidal science.10−15 For example,
glyphosate (Figure 1), structurally similar to a naturally occurring
glutamate analogue, phosphinothricin (PPT, Figure 1), as a
synthetic inhibitor of the shikimate pathway enzyme 5-enol-
pyruvyl-shikimate-3-phosphate (EPSP) synthase (EC 2.5.1.19),
is used worldwide as a broad-spectrum herbicide.16−18 Moreover,
Received: May 12, 2015
Revised: July 18, 2015
Accepted: July 29, 2015
© XXXX American Chemical Society
A
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
Figure 1. Structures of commercial α-amino phosphonic acid and pyrimidine pesticides.
anhydrous Mg(ClO4)2 (0.033 g, 0.15 mmol) in anhydrous acetonitrile
(5 mL) was stirred at 50−60 °C until the reaction finished (monitored
by TLC). The solid was filtered off, the solvent was removed under
reduced pressure, and the crude product was purified by column
chromatography on silica gel using a mixture of petroleum ether and
acetone (v/v, 2:1) as eluent to give the target compounds I, II, and III
as a white solid or light yellow oil. The detailed procedures and
spectral data for intermediates 1a−1c and 2a−2b and the target
compounds I−IV are available in the Supporting Information. Ia−Ir
are known compounds, and their spectra data can also be found in the
literature.32
four series of novel α-amino alkyl phosphonate derivatives
containing a pyrimidinyl moiety via a Lewis acid (magnesium
perchlorate) catalyzed Mannich-type reaction of aldehydes,
amines, and phosphites (Schemes 1 and 2). The target
Scheme 1. Molecular Design of Title Compounds I−IV
Data for compound Is (R = Et, Ar = 4-FC6H4): white solid; yield,
71%; mp, 125.3−126.5 °C; IR (KBr) ν 3316 (NH), 2981 (ArH),
1600, 1572, 1502, 1468 (Ar), 1362 (PO), 1216, 1193 (POC),
1
1066, 1025 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.06
(t, J = 7.8 Hz, 3H, CH3), 1.30 (t, J = 7.2 Hz, 3H, CH3), 3.70−3.74 (m,
1H, CH2), 3.79 (s, 6H, 2CH3O), 3.88−3.94 (m, 1H, CH2), 4.17−4.22
(m, 2H, CH2), 4.65 (t, J = 8.4 Hz, 1H, NH), 5.15 (dd, J = 8.4 Hz,
J = 24.0 Hz, 1H, PCH), 5.79 (s, 1H, pyrimidine-H), 6.49−6.51
(m, 2H, ArH), 6.71 (t, J = 8.4 Hz, 2H, ArH), 7.20 (d, J = 7.2 Hz, 2H,
ArH), 7.28 (t, J = 7.8 Hz, 1H, ArH), 7.63 (d, J = 7.2 Hz, 1H, ArH); 31P
NMR (CDCl3, 162 MHz) δ 21.90; EI-MS (70 eV) m/z (%) 491.4
(M+, 2.7), 355 (23.7), 354 (100), 214 (12.8). Anal. Calcd for
C23H27FN3O6P: C, 56.21; H, 5.54; N, 8.55. Found: C, 56.07; H, 5.39;
N, 8.31.
compounds were evaluated for herbicidal activities in vitro
and in vivo, and their preliminary herbicidal mode of action and
structure−activity relationship were also studied.
Data for compound It (R = Me, Ar = 4-FC6H4): white solid; yield,
66%; mp, 159.4−160.7 °C; IR (KBr) ν 3319 (NH), 2983 (ArH),
1605, 1571, 1507, 1470 (Ar), 1358 (PO), 1219, 1187 (POC),
1065, 1022 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 3.46
MATERIALS AND METHODS
1
■
Instruments. 1H and 31P NMR spectra were performed on a
Varian Mercury-PLUS400 (400 MHz) or Varian Mercury Plus-600
(600 MHz) spectrometer at room temperature in CDCl3 with TMS
and 85% H3PO4 as the internal and external standards, respectively;
chemical shift values (δ) are given in parts per million. Elemental
analyses were taken on a Vario EL III elemental analysis instrument.
Mass spectra were measured on a Finnigan TraceMS 2000 spec-
trometer at 70 eV using EI method or an Applied Biosystems API
2000 LC/MS/MS (ESI-MS) spectrometer. The IR spectra were
recorded on a Nicolet NEXUS470 spectrometer as KBr pellets with
absorption given in cm−1. The melting points were determined on an
X-4 binocular microscope melting point apparatus (Beijing Tech
Instruments Co., Beijing, China) and were uncorrected. Analytical
TLC was performed on silica gel GF254. Column chromatographic
purification was carried out using silica gel. Yields were not optimized.
Unless otherwise noted, all materials were commercially available and
were used directly without further purification. All solvents were dried
and redistilled before use.
(d, J = 10.8 Hz, 3H, OCH3), 3.80 (s, 6H, 2CH3O), 3.88 (d, J =
10.8 Hz, 3H, OCH3), 4.64 (br s, 1H, NH), 5.19 (dd, J = 7.8 Hz, J =
24.0 Hz, 1H, PCH), 5.79 (s, 1H, pyrimidine-H), 6.50−6.53 (m, 2H,
ArH), 6.72 (t, J = 7.8 Hz, 2H, ArH), 7.22 (t, J = 7.8 Hz, 2H, ArH),
7.31 (t, J = 7.8 Hz, 1H, ArH), 7.62 (d, J = 7.8 Hz, 1H, ArH); 31P NMR
(CDCl3, 162 MHz) δ 24.20; EI-MS (70 eV) m/z (%) 463.4 (M+, 2.9),
355 (22.0), 354 (100), 322 (5.1), 214 (14.4). Anal. Calcd for
C21H23FN3O6P: C, 54.43; H, 5.00; N, 9.07. Found: C, 54.62; H, 5.15;
N, 9.26.
Data for compound Iu (R = Ph, Ar = 4-FC6H4): white solid; yield,
75%; mp, 173.4−174.3 °C; IR (KBr) ν 3311 (NH), 2980 (ArH),
1608, 1577, 1502, 1475 (Ar), 1361 (PO), 1216, 1182 (POC),
1
1062, 1028 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 3.71
(s, 6H, 2CH3O), 4.74 (br s, 1H, NH), 5.62 (dd, J = 9.0 Hz, J =
24.6 Hz, 1H, PCH), 5.72 (s, 1H, pyrimidine-H), 6.56−6.58 (m, 2H,
ArH), 6.73−6.78 (m, 4H, ArH), 7.06−7.09 (m, 3H, ArH), 7.12−7.18
(m, 3H, ArH), 7.21−7.25 (m, 4H, ArH), 7.33 (t, J = 7.8 Hz, 1H, ArH),
7.70 (d, J = 8.4 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 14.60;
EI-MS (70 eV) m/z (%) 587.5 (M+, 1.7), 355 (21.0), 354 (100), 353
(39.3), 338 (5.9), 258 (6.8). 234 (18.0), 214 (47.5). Anal. Calcd for
C31H27FN3O6P: C, 63.37; H, 4.63; N, 7.15. Found: C, 63.16; H, 4.58;
N, 7.22.
General Procedure for the Preparation of O,O′-Dialkyl
(Diphenyl) N-Substituted Phenyl-1-amino-[2 or 3 or 4-(4,6-
dimethoxypyrimidin-2-yloxy)phenyl]methyl Phosphonates
I−III. The mixture of aldehyde 1a−1c (3 mmol), dialkyl phosphite,
or diphenyl phosphite (3 mmol), substituted aniline (3.3 mmol), and
B
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
Scheme 2. Synthetic Route of Title Compounds I−III
Data for compound Iv (R = Et, Ar = 2-BrC6H4): white solid; yield,
64%; mp, 113.2−114.6 °C; IR (KBr) ν 3309 (NH), 2976 (ArH),
1598, 1563, 1500, 1472 (Ar), 1359 (PO), 1218, 1194 (POC),
1738 (CO), 1561, 1554, 1481, 1459 (Ar), 1362 (PO), 1218,
1
1183 (POC), 1057, 1028 (COC) cm−1; H NMR (CDCl3,
600 MHz) δ 1.07 (t, J = 7.2 Hz, 3H, CH3), 1.28 (t, J = 7.2 Hz, 3H,
CH3), 1.33 (t, J = 7.8 Hz, 3H, CH3), 3.71−3.74 (m, 1H, CH2), 3.80
(s, 6H, 2CH3O), 3.92−3.95 (m, 1H, CH2), 4.20 (q, J = 7.2 Hz, 2H,
CH2), 4.28 (q, J = 7.2 Hz, 2H, CH2), 5.21 (br s, 1H, NH), 5.28 (d, J =
7.8 Hz, J = 24.0 Hz, 1H, PCH), 5.78 (s, 1H, pyrimidine-H), 6.54 (t, J =
6.0 Hz, 2H, ArH), 7.20−7.23 (m, 2H, ArH), 7.28−7.31 (m, 1H, ArH),
7.62 (d, J = 6.6 Hz, 1H, ArH), 7.71 (t, J = 6.0 Hz, 2H, ArH); 31P NMR
(CDCl3, 162 MHz) δ 21.31; EI-MS (70 eV) m/z (%) 545.5 (M+, 2.5),
410 (4.0), 409 (26.9), 408 (100), 362 (3.6). Anal. Calcd for
C26H32N3O8P: C, 57.24; H, 5.91; N, 7.70. Found: C, 57.06; H, 5.97;
N, 7.63.
1
1062, 1028 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.11
(t, J = 7.2 Hz, 3H, CH3), 1.29 (t, J = 7.2 Hz, 3H, CH3), 3.65−3.68 (m,
1H, CH2), 3.81 (s, 6H, 2CH3O), 3.96−3.99 (m, 1H, CH2), 4.18−4.20
(m, 2H, CH2), 5.24 (d, J = 24.0 Hz, 1H, PCH), 5.41 (br s, 1H, NH),
5.77 (s, 1H, pyrimidine-H), 6.48−6.51 (m, 2H, ArH), 6.89−6.90 (m,
1H, ArH), 7.21−7.23 (m, 2H, ArH), 7.28 (t, J = 8.4 Hz, 1H, ArH),
7.35 (d, J = 7.2 Hz, 1H, ArH), 7.61−7.63 (m, 1H, ArH); 31P NMR
(CDCl3, 162 MHz) δ 21.15; EI-MS (70 eV) m/z (%) 553.4 (5.1),
551.4 (M+, 3.5), 417 (21.5), 416 (94.3), 415 (23.8), 414 (100), 334
(8.3), 229 (6.3), 196 (5.8). Anal. Calcd for C23H27BrN3O6P: C,
50.01; H, 4.93; N, 7.61. Found: C, 50.15; H, 4.97; N, 7.43.
Data for compound IIa (R = Et, Ar = 4-FC6H4): white solid; yield,
65%; mp, 135.2−136.3 °C; IR (KBr) ν 3310 (NH), 2985 (ArH),
1561, 1548, 1482, 1459 (Ar), 1358 (PO), 1219, 1176 (POC),
Data for compound Iw (R = Et, Ar = 4-CNC6H4): white solid;
yield, 59%; mp, 142.3−143.6 °C; IR (KBr) ν 3315 (NH), 2982
(ArH), 2245 (CN), 1563, 1556, 1485, 1461 (Ar), 1365 (PO),
1
1057, 1025 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.12
1
1215, 1185 (POC), 1060, 1024 (COC) cm−1; H NMR
(t, J = 7.8 Hz, 3H, CH3), 1.29 (t, J = 7.8 Hz, 3H, CH3), 3.70 (s, 6H,
2CH3O), 3.71−3.74 (m, 1H, CH2), 3.93−3.97 (m, 1H, CH2), 4.10−
4.14 (m, 2H, CH2), 4.67 (dd, J = 7.2 Hz, J = 24.0 Hz, 1H, PCH), 4.73
(br s, 1H, NH), 5.76 (s, 1H, pyrimidine-H), 6.50−6.52(m, 2H, ArH),
6.78−6.80 (m, 2H, ArH), 7.14 (t, J = 6.6 Hz, 1H, ArH), 7.32 (d, J =
7.2 Hz, 2H, ArH), 7.37 (t, J = 7.8 Hz, 1H, ArH); 31P NMR (CDCl3,
162 MHz) δ 21.43; EI-MS (70 eV) m/z (%) 491.5 (M+, 6.0), 355
(19.2), 354 (100), 353 (7.1), 198 (2.6), 122 (2.9). Anal. Calcd for
C23H27FN3O6P: C, 56.21; H, 5.54; N, 8.55. Found: C, 56.03; H,
5.77; N, 8.39.
(CDCl3, 600 MHz) δ 1.06 (t, J = 7.2 Hz, 3H, CH3), 1.28 (t, J =
7.2 Hz, 3H, CH3), 3.68−3.72 (m, 1H, CH2), 3.81 (s, 6H, 2CH3O),
3.90−3.94 (m, 1H, CH2), 4.15−4.20 (m, 2H, CH2), 5.20 (d, J =
7.8 Hz, J = 24.0 Hz, 1H, PCH), 5.33 (br s, 1H, NH), 5.80 (s, 1H,
pyrimidine-H), 6.57(d, J = 9.0 Hz, 2H, ArH), 7.20−7.24 (m, 2H,
ArH), 7.27−7.29 (m, 2H, ArH), 7.33 (t, J = 7.8 Hz, 1H, ArH), 7.59
(d, J = 7.8 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 20.96;
EI-MS (70 eV) m/z (%) 498.4 (M+, 5.8), 362 (24.4), 361 (100), 329
(2.2), 246 (2.4), 244 (3.1), 229 (4.2). Anal. Calcd for C24H27N4O6P: C,
57.83; H, 5.46; N, 11.24. Found: C, 57.70; H, 5.33; N, 11.31.
Data for compound IIb (R = Et, Ar = 2-BrC6H4): white solid; yield,
72%; mp, 108.2−109.8 °C; IR (KBr) ν 3302 (NH), 2988 (ArH),
1567, 1542, 1479, 1452 (Ar), 1367 (PO), 1211, 1170 (POC),
Data for compound Ix (R = Et, Ar = 4-EtOCOC6H4): white solid;
yield, 66%; mp, 160.2−161.3 °C; IR (KBr) ν 3316 (NH), 2975 (ArH),
C
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
1
1068, 1024 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.19
pyrimidine-H), 5.91 (t, J = 8.4 Hz, 1H, NH), 6.61 (d, J = 9.0 Hz, 2H,
ArH), 7.22 (d, J = 8.4 Hz, 2H, ArH), 7.48 (d, J = 8.4 Hz, 2H, ArH),
8.02 (d, J = 9.0 Hz, 2H, ArH); 31P NMR (CDCl3, 243 MHz) δ 20.49.
Anal. Calcd for C23H27N4O8P: C, 53.28; H, 5.25; N, 10.81. Found: C,
53.12; H, 5.40; N, 10.87.
Data for compound IIIf (R = Et, Ar = 4-BrC6H4): white solid; yield,
81%; mp, 136.5−137.3 °C; IR (KBr) ν 3361 (NH), 2985 (ArH),
1579, 1572, 1499 (Ar), 1360 (PO), 1226 (POC), 1158, 1025
(COC) cm−1; 1H NMR (CDCl3, 600 MHz) δ 1.12 (t, J = 7.2 Hz,
3H, CH3), 1.29 (t, J = 7.2 Hz, 3H, CH3), 3.65−3.72 (m, 1H, CH2),
3.77 (s, 6H, 2CH3O), 3.92−3.98 (m, 1H, CH2), 4.08−4.16 (m, 2H,
CH2), 4.72 (dd, J = 6.0 Hz, J = 24.0 Hz, 1H, PCH), 4.93 (br s, 1H,
NH), 5.76 (s, 1H, pyrimidine-H), 6.47 (d, J = 9.0 Hz, 2H, ArH),
7.16 (d, J = 8.4 Hz, 2H, ArH), 7.18 (d, J = 8.4 Hz, 2H, ArH), 7.46 (d,
J = 8.4 Hz, 2H, ArH); 31P NMR (CDCl3, 243 MHz) δ 21.47. Anal.
Calcd for C23H27BrN3O6P: C, 50.01; H, 4.93; N, 7.61. Found: C,
49.87; H, 4.74; N, 7.80.
(t, J = 7.8 Hz, 3H, CH3), 1.28 (t, J = 7.2 Hz, 3H, CH3), 3.73 (s, 6H,
2CH3O), 3.82−3.86 (m, 1H, CH2), 4.00−4.14 (m, 3H, CH2), 4.76
(dd, J = 6.6 Hz, J = 24.6 Hz, 1H, PCH), 5.45 (br s, 1H, NH), 5.76 (s,
1H, pyrimidine-H), 6.43 (d, J = 7.8 Hz, 1H, ArH), 6.59 (d, J = 6.0 Hz,
1H, ArH), 6.99 (t, J = 7.2 Hz, 1H, ArH), 7.14 (d, J = 7.8 Hz, 1H,
ArH), 7.35−7.39 (m, 3H, ArH), 7.42 (d, J = 7.8 Hz, 1H, ArH); 31P
NMR (CDCl3, 162 MHz) δ 20.55; EI-MS (70 eV) m/z (%) 553.4
(4.1), 551 (M+, 4.6), 417 (22.6), 416 (99.7), 415 (24.3), 414 (100),
208 (5.3). Anal. Calcd for C23H27BrN3O6P: C, 50.01; H, 4.93; N, 7.61.
Found: C, 49.93; H, 4.74; N, 7.82.
Data for compound IIIa (R = Et, Ar = 4-FC6H4): white solid; yield,
75%; mp, 138.5−139.6 °C; IR (KBr) ν 3319 (NH), 2983 (ArH),
1604, 1569, 1506 (Ar), 1364 (PO), 1217, 1196 (POC), 1065,
1024 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.13 (t, J =
1
7.8 Hz, 3H, CH3), 1.30 (t, J = 7.2 Hz, 3H, CH3), 3.69−3.74 (m, 1H,
CH2), 3.77 (s, 6H, 2CH3O), 3.94−3.98 (m, 1H, CH2), 4.10−4.16 (m,
2H, CH2), 4.70 (dd, J = 7.8 Hz, J = 26.4 Hz, 1H, PCH), 4.73 (br s, 1H,
NH), 5.77 (s, 1H, pyrimidine-H), 6.53 (dd, J = 4.2 Hz, J = 7.8 Hz, 2H,
ArH), 6.80 (t, J = 8.4 Hz, 2H, ArH), 7.19 (d, J = 8.4 Hz, 2H, ArH),
7.47 (dd, J = 1.8 Hz, J = 8.4 Hz, 2H, ArH); 31P NMR (CDCl3, 162
MHz) δ 21.74; EI-MS (70 eV) m/z (%) 491.4 (M+, 2.2), 355 (17.8),
354 (100), 353 (8.7), 197 (2.8), 111 (2.4). Anal. Calcd for
C23H27FN3O6P: C, 56.21; H, 5.54; N, 8.55. Found: C, 56.43; H,
5.37; N, 8.62.
Data for compound IIIg (R = Et, Ar = C6H5): white solid; yield,
74%; mp, 131.7−133.1 °C; IR (KBr) ν 3345 (NH), 2980 (ArH),
1582, 1570, 1486 (Ar), 1359 (PO), 1223 (POC), 1153, 1027
1
(COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.13 (t, J = 10.8
Hz, 3H, CH3), 1.29 (t, J = 10.8 Hz, 3H, CH3), 3.66−3.74 (m, 1H,
CH2), 3.78 (s, 6H, 2CH3O), 3.93−3.99 (m, 1H, CH2), 4.08−4.17 (m,
2H, CH2), 4.78 (d, J = 24.0 Hz, 1H, PCH), 4.82 (br s, 1H, NH), 5.76
(s, 1H, pyrimidine-H), 6.60 (d, J = 12 Hz, 2H, ArH), 6.70 (t, J = 10.8
Hz, 1H, ArH), 7.10 (t, J = 12.0 Hz, 2H, ArH), 7.18 (d, J = 12.0 Hz,
2H, ArH), 7.49 (d, J = 12.0 Hz, 2H, ArH); 31P NMR (CDCl3, 243
MHz) δ 21.76. Anal. Calcd for C23H28N3O6P: C, 58.35; H, 5.96; N,
8.88. Found: C, 58.51; H, 6.03; N, 8.74.
Data for compound IIIb (R = Et, Ar = 2-BrC6H4): white solid; yield,
70%; mp, 100.4−101.3 °C; IR (KBr) ν 3395 (NH), 2982 (ArH),
1592, 1573, 1505 (Ar), 1367 (PO), 1224 (POC), 1164, 1020
(COC) cm−1; 1H NMR (CDCl3, 600 MHz) δ 1.19 (t, J = 7.2 Hz,
3H, CH3), 1.28 (t, J = 7.8 Hz, 3H, CH3), 3.76 (s, 6H, 2CH3O), 3.81−
3.85 (m, 1H, CH2), 4.00−4.16 (m, 3H, CH2), 4.80 (dd, J = 7.2 Hz,
J = 24.6 Hz, 1H, PCH), 5.45 (t, J = 7.8 Hz, 1H, NH), 5.77 (s, 1H,
pyrimidine-H), 6.44 (d, J = 7.8 Hz, 1H, ArH), 6.58 (t, J = 7.2 Hz, 1H,
ArH), 7.01 (t, J = 7.8 Hz, 1H, ArH), 7.19 (d, J = 8.4 Hz, 2H, ArH),
7.43 (d, J = 8.4 Hz, 1H, ArH), 7.48 (d, J = 8.4 Hz, 2H, ArH); 31P
NMR (CDCl3, 162 MHz) δ 20.85; EI-MS (70 eV) m/z (%) 553.4
(M+, 1.5), 417 (19.0), 416 (100), 415 (23.6), 414 (94.8), 259 (3.3).
Anal. Calcd for C23H27BrN3O6P: C, 50.01; H, 4.93; N, 7.61. Found: C,
49.85; H, 4.80; N, 7.44.
Data for compound IIIh (R = Et, Ar = 2,4-Cl2C6H3): white solid;
yield, 73%; mp, 147.5−148.7 °C; IR (KBr) ν 3364 (NH), 2982 (ArH),
1577, 1570, 1500 (Ar), 1360 (PO), 1223 (POC), 1159, 1022
1
(COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.18 (t, J = 10.8
Hz, 3H, CH3), 1.28 (t, J = 10.8 Hz, 3H, CH3), 3.79 (s, 6H, 2CH3O),
3.80−3.83 (m, 1H, CH2), 3.98−4.17 (m, 3H, CH2), 4.74 (dd, J =
10.8 Hz, J = 36.0 Hz, 1H, PCH), 5.39 (dd, J = 10.8 Hz, J = 15.6 Hz,
1H, NH), 5.77 (s, 1H, pyrimidine-H), 6.38 (d, J = 13.2 Hz, 1H, ArH),
6.93 (d, J = 13.2 Hz, 1H, ArH), 7.20 (d, J = 12.6 Hz, 2H, ArH), 7.27
(s, 1H, ArH), 7.44 (dd, J = 3.6 Hz, J = 13.2 Hz, 2H, ArH); 31P NMR
(CDCl3, 243 MHz) δ 19.98. Anal. Calcd for C23H26Cl2N3O6P: C,
50.94; H, 4.83; N, 7.75. Found: C, 50.81; H, 4.88; N, 7.91.
Data for compound IIIc (R = Et, Ar = 4-ClC6H4): white solid;
yield, 78%; mp, 142.3−143.9 °C; IR (KBr) ν 3367 (NH), 2987 (Ar
H), 1582, 1574, 1501 (Ar), 1364 (PO), 1228 (POC), 1161,
Data for compound IIIi (R = Me, Ar = 4-ClC6H4): white solid;
yield, 87%; mp, 145.0−146.4 °C; IR (KBr) ν 3351 (NH), 2980 (ArH),
1577, 1571, 1496 (Ar), 1353 (PO), 1231 (POC), 1159, 1022
1026 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.12 (t, J =
1
7.2 Hz, 3H, CH3), 1.30 (t, J = 7.2 Hz, 3H, CH3), 3.65−3.72 (m, 1H,
CH2), 3.78 (s, 6H, 2CH3O), 3.93−3.97 (m, 1H, CH2), 4.10−4.15
(m, 2H, CH2), 4.72 (d, J = 24.0 Hz, 1H, PCH), 5.77 (s, 1H,
pyrimidine-H), 6.52 (d, J = 7.8 Hz, 2H, ArH), 7.03 (d, J = 8.4 Hz, 2H,
ArH), 7.18 (d, J = 8.4 Hz, 2H, ArH), 7.45 (d, J = 8.4 Hz, 2H, ArH);
31P NMR (CDCl3, 243 MHz) δ, 21.80. Anal. Calcd for
C23H27ClN3O6P: C, 54.39; H, 5.36; N, 8.27. Found: C, 54.53; H,
5.22; N, 8.39.
1
(COC) cm−1; H NMR (CDCl3, 400 MHz) δ 3.48 (d, J = 10.4
Hz, 3H, OCH3), 3.77 (s, 6H, 2CH3O), 3.79 (d, J = 10.4 Hz, 3H,
OCH3), 4.76 (d, J = 25.6 Hz, 1H, PCH), 4.87 (br s, 1H, NH), 5.77 (s,
1H, pyrimidine-H), 6.52 (d, J = 8.8 Hz, 2H, ArH), 7.04 (d, J = 8.8 Hz,
2H, ArH), 7.20 (d, J = 8.4 Hz, 2H, ArH), 7.47 (dd, J = 2.4 Hz, J =
8.8 Hz, 2H, ArH); 31P NMR (CDCl3, 162 MHz) δ 23.49. Anal. Calcd
for C21H23ClN3O6P: C, 52.56; H, 4.83; N, 8.76. Found: C, 54.72;
H, 4.97; N, 8.94.
Data for compound IIId (R = Et, Ar = 4-CH3C6H4): white solid;
yield, 72%; mp, 133.3−134.5 °C; IR (KBr) ν 3351 (NH), 2990 (ArH),
1575, 1568, 1506 (Ar), 1360 (PO), 1232 (POC), 1159, 1027
(COC) cm−1; 1H NMR (CDCl3, 600 MHz) δ 1.13 (t, J = 7.2 Hz,
3H, CH3), 1.29 (t, J = 7.2 Hz, 3H, CH3), 2.19 (s, 3H, CH3), 3.71−3.74
(m, 1H, CH2), 3.78 (s, 6H, 2CH3O), 3.93−3.99 (m, 1H, CH2), 4.06−
4.17 (m, 2H, CH2), 4.75 (dd, J = 6.0 Hz, J = 24.0 Hz, 1H, PCH), 5.77
(s, 1H, pyrimidine-H), 6.52 (d, J = 7.8 Hz, 2H, ArH), 6.91 (d, J =
7.8 Hz, 2H, ArH), 7.17 (d, J = 7.8 Hz, 2H, ArH), 7.48 (d, J = 7.2 Hz,
2H, ArH); 31P NMR (CDCl3, 243 MHz) δ 21.58. Anal. Calcd for
C24H30N3O6P: C, 59.13; H, 6.20; N, 8.62. Found: C, 59.01; H, 6.08;
N, 8.51.
Data for compound IIIe (R = Et, Ar = 4-NO2C6H4): white solid;
yield, 79%; mp, 195.3−196.3 °C; IR (KBr) ν 3334 (NH), 2993 (ArH),
1579, 1562, 1507 (Ar), 1354 (PO), 1229 (POC), 1164, 1033
(COC) cm−1; 1H NMR (CDCl3, 600 MHz) δ 1.13 (t, J = 7.2 Hz,
3H, CH3), 1.31 (t, J = 7.2 Hz, 3H, CH3), 3.65−3.71 (m, 1H, CH2),
3.79 (s, 6H, 2CH3O), 3.93−3.98 (m, 1H, CH2), 4.11−4.18 (m, 2H,
CH2), 4.85 (dd, J = 7.8 Hz, J = 24.0 Hz, 1H, PCH), 5.78 (s, 1H,
Data for compound IIIj (R = Et, Ar = 2-FC6H4): white solid; yield,
73%; mp, 133.6−135.1 °C; IR (KBr) ν 3318 (NH), 2991 (ArH),
1559, 1561, 1477, 1463 (Ar), 1366 (PO), 1227, 1170 (POC),
1
1052, 1028 (COC) cm−1; H NMR (CDCl3, 400 MHz) δ 1.16
(t, J = 7.2 Hz, 3H, CH3), 1.28 (t, J = 7.2 Hz, 3H, CH3), 3.77 (s, 6H,
2CH3O), 3.80−3.84 (m, 1H, CH2), 3.95−4.03 (m, 1H, CH2), 4.05−
4.16 (m, 2H, CH2), 4.77 (d, J = 22.8 Hz, 1H, PCH), 4.98 (br s, 1H,
NH), 5.77 (s, 1H, pyrimidine-H), 6.51(t, J = 8.4 Hz, 1H, ArH), 6.63(q,
J = 7.6 Hz, 1H, ArH), 6.83 (t, J = 7.6 Hz, 1H, ArH), 6.97 (t, J = 9.6 Hz,
1H, ArH), 7.19 (d, J = 8.4 Hz, 2H, ArH), 7.48 (dd, J = 2.4 Hz, J =
8.8 Hz, 2H, ArH); 31P NMR (CDCl3, 162 MHz) δ 20.73. Anal. Calcd
for C23H27FN3O6P: C, 56.21; H, 5.54; N, 8.55. Found: C, 56.31;
H, 5.39; N, 8.42.
General Procedure for the Preparation of O,O′-Dialkyl
(Diphenyl) N-[2-(4,6-Dimethoxypyrimidin-2-yloxy or thio
phenyl]-1-amino (Substituted Phenyl) Methyl Phosphonates
IV. The mixture of amine 2 (3 mmol), dialkyl phosphite or diphenyl
phosphite (3 mmol), substituted benzaldehyde (3.3 mmol), and
D
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
Scheme 3. Synthetic Route of Title Compounds IV
anhydrous Mg(ClO4)2 (0.033 g, 0.15 mmol) in anhydrous acetonitrile
(5 mL) was stirred at 50−60 °C until the reaction completed
(monitored by TLC). The solid was filtered off, the solvent was
removed under reduced pressure, and the crude product was purified
by column chromatography on silica gel using a mixture of petroleum
ether and acetone (v/v, 2:1) as eluent to yield the target compound IV
(Scheme 3) as white solid or light yellow oil.
Data for compound IVc (R = Et, X = S, Ar = 4-CH3OC6H4): white
solid; yield, 66%; mp, 169.7−170.9 °C; IR (KBr) ν 3342 (NH), 2984
(ArH), 1583, 1549, 1508 (Ar), 1371 (PO), 1260, 1193 (PO
1
C), 1054, 1014 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ
1.12 (t, J = 7.2 Hz, 3H, CH3), 1.18 (t, J = 7.2 Hz, 3H, CH3), 3.64 (s,
6H, 2CH3O), 3.71−3.75 (m, 1H, CH2), 3.77 (s, 3H, OCH3), 3.88−
3.95 (m, 2H, CH2), 3.97−4.03 (m, 1H, CH2), 4.73 (dd, J = 6.0 Hz, J =
24.0 Hz, 1H, PCH), 5.72 (s, 1H, pyrimidine-H), 5.84 (t, J = 7.8 Hz,
1H, NH), 6.50 (d, J = 8.4 Hz, 1H, ArH), 6.68 (t, J = 7.8 Hz, 1H, ArH),
6.80 (d, J = 8.4 Hz, 2H, ArH), 7.16 (t, J = 8.4 Hz, 1H, ArH), 7.25 (d,
J = 7.8 Hz, 2H, ArH), 7.45 (d, J = 7.8 Hz, 1H, ArH); 31P NMR
(CDCl3, 162 MHz) δ 21.23; EI-MS (70 eV) m/z (%) 519.3 (M+, 3.9),
384 (7.8), 383 (23.7), 382 (100), 274 (11.8), 247 (3.4), 243 (3.6), 242
(21.9), 210 (4.5). Anal. Calcd for C24H30N3O6PS: C, 55.48; H, 5.82;
N, 8.09. Found: C, 57.63; H, 5.73; N, 7.97.
Data for compound IVa (R = Et, X = S, Ar = C6H5): white solid;
yield, 68%; mp, 120.3−122.2 °C; IR (KBr) ν 3345 (NH), 2985 (ArH),
1586, 1552, 1504 (Ar), 1370 (PO), 1278, 1190 (POC), 1042,
1
1015 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.10 (t, J =
7.2 Hz, 3H, CH3), 1.18 (t, J = 7.2 Hz, 3H, CH3), 3.64 (s, 6H, 2CH3O),
3.70−3.74 (m, 1H, CH2), 3.89−3.95 (m, 2H, CH2), 3.99−4.02 (m,
1H, CH2), 4.78 (dd, J = 7.8 Hz, J = 24.0 Hz, 1H, PCH), 5.72 (s, 1H,
pyrimidine-H), 5.91 (t, J = 8.4 Hz, 1H, NH), 6.48 (d, J = 8.4 Hz, 1H,
ArH), 6.68 (t, J = 7.2 Hz, 1H, ArH), 7.15 (t, J = 7.8 Hz, 1H, ArH),
7.23−7.28 (m, 3H, ArH), 7.35 (d, J = 7.8 Hz, 2H, ArH), 7.46 (d, J =
7.2 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 20.96; EI-MS
(70 eV) m/z (%) 489.4 (M+, 5.0), 354 (7.0), 353 (22.9), 352 (100),
212 (14.8), 180 (6.1), 136 (3.5), 109 (4.9). Anal. Cacld for
C23H28N3O5PS: C, 56.43; H, 5.77; N, 8.58. Found: C, 56.65;
H, 5.58; N, 8.70.
Data for compound IVd (R = Et, X = S, Ar = 4-FC6H4): white solid;
yield, 69%; mp, 164.6−165.9 °C; IR (KBr) ν 3348 (NH), 2984 (ArH),
1586, 1550, 1503 (Ar), 1372 (PO), 1293, 1194 (POC), 1045,
1
1014 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.13 (t, J =
7.2 Hz, 3H, CH3), 1.18 (t, J = 7.2 Hz, 3H, CH3), 3.65 (s, 6H, 2CH3O),
3.76−3.79 (m, 1H, CH2), 3.91−3.96 (m, 2H, CH2), 4.00−4.02 (m,
1H, CH2), 4.76 (dd, J = 5.4 Hz, J = 24.6 Hz, 1H, PCH), 5.73 (s, 1H,
pyrimidine-H), 5.86 (br s, 1H, NH), 6.44 (d, J = 7.8 Hz, 1H, ArH),
6.70 (t, J = 7.8 Hz, 1H, ArH), 6.97 (t, J = 9.0 Hz, 2H, ArH), 7.16 (t,
J = 7.8 Hz, 1H, ArH), 7.33 (t, J = 6.0 Hz, 2H, ArH), 7.47 (d, J =
7.8 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 20.40; EI-MS
(70 eV) m/z (%) 507.3 (M+, 5.2), 372 (6.3), 371 (21.8), 370 (100),
274 (5.0), 230 (16.5), 198 (7.6), 136 (4.4), 109 (9.6). Anal. Calcd for
C23H27FN3O5PS: C, 54.43; H, 5.36; N, 8.28. Found: C, 54.55; H, 5.51;
N, 8.40.
Data for compound IVb (R = Et, X = S, Ar = 4-CH3C6H4): white
solid; yield, 72%; mp, 109.1−110.3 °C; IR (KBr) ν 3347 (NH),
2988 (ArH), 1581, 1558, 1501 (Ar), 1366 (PO), 1275, 1182
(POC), 1041, 1021 (COC) cm−1; 1H NMR (CDCl3,
600 MHz) δ 1.12 (t, J = 7.2 Hz, 3H, CH3), 1.19 (t, J = 7.2 Hz, 3H,
CH3), 2.30 (s, 3H, CH3), 3.64 (s, 6H, 2CH3O), 3.72−3.76 (m, 1H,
CH2), 3.90−3.95 (m, 2H, CH2), 3.99−4.03 (m, 1H, CH2), 4.74 (dd,
J = 7.8 Hz, J = 24.6 Hz, 1H, PCH), 5.72 (s, 1H, pyrimidine-H), 5.86
(t, J = 9.0 Hz, 1H, NH), 6.50 (d, J = 8.4 Hz, 1H, ArH), 6.68 (t, J =
7.2 Hz, 1H, ArH), 7.06 (d, J = 7.8 Hz, 2H, ArH), 7.15 (t, J = 7.2 Hz,
1H, ArH), 7.22 (d, J = 7.8 Hz, 2H, ArH), 7.45 (d, J = 7.8 Hz, 1H,
ArH); 31P NMR (CDCl3, 162 MHz) δ 21.16; EI-MS (70 eV) m/z (%)
503.3 (M+, 4.7), 368 (7.5), 367 (23.7), 366 (100), 274 (7.0), 226
(18.2), 194 (6.8). Anal. Calcd for C24H30N3O5PS: C, 57.24; H, 6.00;
N, 8.34. Found: C, 57.11; H, 6.13; N, 8.24.
Data for compound IVe (R = Et, X = S, Ar = 2-FC6H4): white solid;
yield, 72%; mp, 138.6−139.5 °C; IR (KBr) ν 3345 (NH), 2987 (ArH),
1582, 1551 (Ar), 1370 (PO), 1289, 1191 (POC), 1048, 1016
(COC) cm−1; 1H NMR (CDCl3, 600 MHz) δ 1.10 (t, J = 6.6 Hz,
3H, CH3), 1.23 (t, J = 7.2 Hz, 3H, CH3), 3.60 (s, 6H, 2CH3O), 3.78−
3.81 (m, 1H, CH2), 3.93−3.97 (m, 1H, CH2), 4.05−4.12 (m, 2H,
CH2), 5.22 (dd, J = 8.4 Hz, J = 24.6 Hz, 1H, PCH), 5.70 (s, 1H,
pyrimidine-H), 5.90 (t, J = 6.0 Hz, 1H, NH), 6.59 (d, J = 8.4 Hz, 1H,
E
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
ArH), 6.70 (t, J = 7.2 Hz, 1H, ArH), 6.99 (t, J = 7.8 Hz, 1H, ArH),
7.04 (t, J = 9.0 Hz, 1H, ArH), 7.18−7.24 (m, 2H, ArH), 7.27 (t, J =
7.2 Hz, 1H, ArH), 7.45 (dd, J = 1.2 Hz, J = 8.4 Hz, 1H, ArH); 31P
NMR (CDCl3, 162 MHz) δ 20.33; EI-MS (70 eV) m/z (%) 507.3
(M+, 6.0), 372 (6.6), 371 (22.0), 370 (100), 274 (3.9), 247 (2.8), 230
(16.2), 198 (5.6), 139 (4.2), 136 (4.2), 109 (6.5). Anal. Calcd for
C23H27FN3O5PS: C, 54.43; H, 5.36; N, 8.28. Found: C, 54.37; H, 5.17;
N, 8.33.
(t, J = 7.2 Hz, 3H, CH3), 1.18 (t, J = 7.2 Hz, 3H, CH3), 3.66 (s, 6H,
2CH3O), 3.78−3.85 (m, 1H, CH2), 3.91−4.04 (m, 3H, CH2), 4.73
(dd, J = 7.2 Hz, J = 24.6 Hz, 1H, PCH), 5.74 (s, 1H, pyrimidine-H),
5.85 (t, J = 9.0 Hz, 1H, NH), 6.42 (d, J = 8.4 Hz, 1H, ArH), 6.71 (t,
J = 7.2 Hz, 1H, ArH), 7.16 (t, J = 7.2 Hz, 1H, ArH), 7.24 (d, J = 8.4
Hz, 2H, ArH), 7.40 (d, J = 8.4 Hz, 2H, ArH), 7.47 (d, J = 7.2 Hz, 1H,
ArH); 31P NMR (CDCl3, 162 MHz) δ 20.85; EI-MS (70 eV) m/z (%)
569.2 (6.0), 567.2 (M+, 6.4), 433 (20.1), 432 (100), 431 (21.6), 430
(95.5), 292 (15.9), 290 (13.5), 247 (5.6), 211 (6.8), 140 (7.2), 139
(7.4), 136 (9.7), 109 (8.8). Anal. Calcd for C23H27BrN3O5PS: C,
48.60; H, 4.79; N, 7.39. Found: C, 48.71; H, 4.55; N, 7.17.
Data for compound IVf (R = Et, X = S, Ar = 2-ClC6H4): white
solid; yield, 75%; mp, 140.7−141.4 °C; IR (KBr) ν 3356 (NH), 2982
(ArH), 1587, 1550 (Ar), 1373 (PO), 1289, 1191 (POC),
1
1050, 1027 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.07
Data for compound IVk (R = Et, X = S, Ar = 3-NO2C6H4): light
yellow solid; yield, 69%; mp, 173.2−174.3 °C; IR (KBr) ν 3352 (NH),
2979 (ArH), 1587, 1551 (Ar), 1362 (PO), 1292, 1186 (P
OC), 1053, 1025 (COC) cm−1; 1H NMR (CDCl3, 600 MHz)
δ 1.16 (t, J = 7.2 Hz, 3H, CH3), 1.20 (t, J = 7.2 Hz, 3H, CH3), 3.66 (s,
6H, 2CH3O), 3.86−3.93 (m, 1H, CH2), 3.95−4.09 (m, 2H, CH2),
4.13−4.20 (m, 1H, CH2), 4.88 (dd, J = 7.2 Hz, J = 25.2 Hz, 1H, PCH),
5.75 (s, 1H, pyrimidine-H), 5.95 (t, J = 8.4 Hz, 1H, NH), 6.41 (d,
J = 8.4 Hz, 1H, ArH), 6.75 (t, J = 7.2 Hz, 1H, ArH), 7.17 (t, J = 7.8 Hz,
1H, ArH), 7.47 (t, J = 7.8 Hz, 1H, ArH), 7.50 (d, J = 7.2 Hz, 1H,
ArH), 7.73 (d, J = 7.8 Hz, 1H, ArH), 8.13 (d, J = 7.8 Hz, 1H, ArH),
8.25 (s, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 19.35; EI-MS
(70 eV) m/z (%) 534.3 (M+, 5.5), 399 (7.9), 398 (23.4), 397 (100),
212 (4.3), 140 (5.4), 136 (8.4). Anal. Calcd for C23H27N4O7PS: C,
51.68; H, 5.09; N, 10.48. Found: C, 51.87; H, 5.23; N, 10.61.
Data for compound IVl (R = Et, X = S, Ar = 4-NO2C6H4): light
yellow solid; yield, 74%; mp, 180.2−181.5 °C; IR (KBr) ν 3340 (NH),
2959 (ArH), 1574, 1544 (Ar), 1359 (PO), 1285, 1180 (P
OC), 1049, 1027 (COC) cm−1; 1H NMR (CDCl3, 600 MHz)
δ 1.17 (t, J = 7.2 Hz, 3H, CH3), 1.19 (t, J = 7.2 Hz, 3H, CH3), 3.69 (s,
6H, 2CH3O), 3.86−3.92 (m, 1H, CH2), 3.93−3.97 (m, 1H, CH2),
3.99−4.07 (m, 2H, CH2), 4.89 (dd, J = 6.0 Hz, J = 25.2 Hz, 1H, PCH),
5.76 (s, 1H, pyrimidine-H), 5.92 (t, J = 7.2 Hz, 1H, NH), 6.35 (d, J =
7.8 Hz, 1H, ArH), 6.74 (t, J = 7.2 Hz, 1H, ArH), 7.16 (t, J = 7.8 Hz,
1H, ArH), 7.50 (d, J = 7.2 Hz, 1H, ArH), 7.58 (d, J = 7.2 Hz, 2H,
ArH), 8.15 (d, J = 8.4 Hz, 2H, ArH); 31P NMR (CDCl3, 162 MHz)
δ 19.14; EI-MS (70 eV) m/z (%) 534.3 (M+, 6.7), 399 (7.1), 398
(21.0), 397 (100), 211 (4.0), 140 (5.3), 136 (6.7). Anal. Calcd for
C23H27N4O7PS: C, 51.68; H, 5.09; N, 10.48. Found: C, 51.52; H, 5.05;
N, 10.39.
(t, J = 7.2 Hz, 3H, CH3), 1.24 (t, J = 7.2 Hz, 3H, CH3), 3.60 (s, 6H,
2CH3O), 3.66−3.73 (m, 1H, CH2), 3.87−3.94 (m, 1H, CH2), 4.04−
4.13 (m, 2H, CH2), 5.40 (dd, J = 8.4 Hz, J = 24.6 Hz, 1H, PCH), 5.71
(s, 1H, pyrimidine-H), 6.03 (t, J = 9.0 Hz, 1H, NH), 6.52 (d, J =
8.4 Hz, 1H, ArH), 6.69 (t, J = 7.2 Hz, 1H, ArH), 7.10 (t, J = 7.8 Hz,
1H, ArH), 7.18 (d, J = 7.8 Hz, 2H, ArH), 7.31 (d, J = 7.8 Hz, 1H,
ArH), 7.36 (d, J = 7.8 Hz, 1H, ArH), 7.44 (d, J = 7.2 Hz, 1H, ArH);
31P NMR (CDCl3, 162 MHz) δ 20.52; EI-MS (70 eV) m/z (%) 523.3
(M+, 0.39), 489 (4.6), 488 (18.4), 389 (8.4), 388 (42.9), 387 (20.5),
386 (100). Anal. Calcd for C23H27 ClN3O5PS: C, 52.72; H, 5.19; N,
8.02. Found: C, 52.51; H, 5.07; N, 8.14.
Data for compound IVg (R = Et, X = S, Ar = 4-ClC6H4): white
solid; yield, 78%; mp, 143.2−144.4 °C; IR (KBr) ν 3359 (NH), 2980
(ArH), 1584, 1553 (Ar), 1370 (PO), 1285, 1193 (POC),
1
1049, 1024 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.14
(t, J = 7.2 Hz, 3H, CH3), 1.18 (t, J = 7.2 Hz, 3H, CH3), 3.66 (s, 6H,
2CH3O), 3.78−3.84 (m, 1H, CH2), 3.91−3.98 (m, 2H, CH2), 4.00−
4.04 (m, 1H, CH2), 4.75 (dd, J = 7.2 Hz, J = 24.6 Hz, 1H, PCH), 5.74
(s, 1H, pyrimidine-H), 5.86 (t, J = 7.8 Hz, 1H, NH), 6.42 (d, J =
8.4 Hz, 1H, ArH), 6.71 (t, J = 7.2 Hz, 1H, ArH), 7.16 (t, J = 7.8 Hz,
1H, ArH), 7.25 (d, J = 8.4 Hz, 2H, ArH), 7.30 (d, J = 6.6 Hz, 2H,
ArH), 7.47 (d, J = 7.2 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz)
δ 20.62; EI-MS (70 eV) m/z (%) 523.3 (M+, 5.6), 389 (6.6), 388
(34.0), 387 (22.5), 386 (100), 248 (8.2), 247 (7.4), 246 (18.8), 214
(5.2), 140 (4.8), 139 (6.8), 136 (5.7), 109 (9.7). Anal. Calcd for
C23H27ClN3O5PS: C, 52.72; H, 5.19; N, 8.02. Found: C, 52.83; H,
5.35; N, 8.09.
Data for compound IVh (R = Me, X = S, Ar = 4-ClC6H4): white
solid; yield, 69%; mp, 157.8−158.4 °C; IR (KBr) ν 3368 (NH), 2985
(ArH), 1577, 1550 (Ar), 1377 (PO), 1281, 1196 (POC),
Data for compound IVm (R = Et, X = S, Ar = 2,4-(MeO)2C6H3):
white solid; yield, 69%; mp, 110.9−112.1 °C; IR (KBr) ν 3345 (NH),
2951 (ArH), 1578, 1541 (Ar), 1350 (PO), 1283, 1184 (PO
1
1054, 1027 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 3.52
(d, J = 10.2 Hz, 3H, OCH3), 3.64 (d, J = 10.8 Hz, 3H, OCH3), 3.66 (s,
6H, 2CH3O), 4.78 (dd, J = 7.2 Hz, J = 24.0 Hz, 1H, PCH), 5.73 (s,
1H, pyrimidine-H), 5.81 (t, J = 7.2 Hz, 1H, NH), 6.45 (d, J = 8.4 Hz,
1H, ArH), 6.72 (t, J = 7.8 Hz, 1H, ArH), 7.17 (t, J = 7.8 Hz, 1H, ArH),
7.25 (d, J = 7.8 Hz, 2H, ArH), 7.32 (d, J = 7.2 Hz, 2H, ArH), 7.47 (d,
J = 7.2 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 22.83; EI-MS
(70 eV) m/z (%) 495.2 (10.7), 493.8 (M+, 100), 213 (10.2), 212
(95.2), 202 (27.0), 81 (6.6). Anal. Calcd for C21H23ClN3O5PS: C,
50.86; H, 4.67; N, 8.47. Found: C, 50.66; H, 4.80; N, 8.29.
1
C), 1055, 1028 (COC) cm−1; H NMR (CDCl3, 600 MHz)
δ 1.08 (t, J = 7.2 Hz, 3H, CH3), 1.22 (t, J = 7.2 Hz, 3H, CH3), 3.59
(s, 6H, 2CH3O), 3.69−3.73 (m, 1H, CH2), 3.75 (s, 3H, CH3O), 3.88
(s, 3H, CH3O), 3.89−3.92 (m, 1H, CH2), 4.00−4.10 (m, 2H, CH2),
5.30 (dd, J = 9.0 Hz, J = 24.6 Hz, 1H, PCH), 5.69 (s, 1H, pyrimidine-
H), 5.87 (t, J = 9.0 Hz, 1H, NH), 6.32 (d, J = 8.4 Hz, 1H, ArH), 6.42
(s, 1H, ArH), 6.59 (d, J = 8.4 Hz, 1H, ArH), 6.65 (t, J = 7.2 Hz, 1H,
ArH), 7.09 (dd, J = 2.4 Hz, J = 8.4 Hz, 1H, ArH), 7.17 (t, J = 7.2 Hz,
1H, ArH), 7.41 (d, J = 7.8 Hz, 1H, ArH); 31P NMR (CDCl3, 162
MHz) δ 22.09; EI-MS (70 eV) m/z (%) 549.3 (M+, 0.7), 414 (6.9),
413 (24.6), 412 (100), 274 (9.1), 273 (6.8), 272 (38.2). Anal. Calcd
for C25H32N3O7PS: C, 54.64; H, 5.87; N, 7.65. Found: C, 54.70; H,
5.93; N, 7.47.
Data for compound IVi (R = Ph, X = S, Ar = 4-ClC6H4): white
solid; yield, 67%; mp, 129.6−130.8 °C; IR (KBr) ν 3372 (NH), 2987
(ArH), 1571, 1553 (Ar), 1374 (PO), 1275, 1190 (POC),
1
1057, 1025 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 3.63
(s, 6H, 2CH3O), 5.11 (dd, J = 7.8 Hz, J = 25.2 Hz, 1H, PCH), 5.68 (s,
1H, pyrimidine-H), 6.09 (t, J = 7.8 Hz, 1H, NH), 6.50 (d, J = 8.4 Hz,
1H, ArH), 6.76 (t, J = 7.2 Hz, 1H, ArH), 6.91 (d, J = 8.4 Hz, 2H,
ArH), 6.94 (d, J = 8.4 Hz, 2H, ArH), 7.11 (t, J = 7.8 Hz, 2H, ArH),
7.18−7.25 (m, 7H, ArH), 7.37 (d, J = 9.0 Hz, 2H, ArH), 7.51 (d, J =
7.8 Hz, 1H, ArH); 31P NMR (CDCl3, 162 MHz) δ 12.99; EI-MS
(70 eV) m/z (%) 619.4 (9.3), 618.7 (M+, 16.2), 617 (15.1), 608
(22.3), 607 (16.9), 556 (13.8), 504 (11.9), 415 (11.0), 254 (57.8), 253
(73.2), 200 (100). Anal. Calcd for C31H27ClN3O5PS: C, 60.05; H,
4.39; N, 6.78. Found: C, 59.87; H, 4.44; N, 6.97.
Data for compound IVn (R = Et, X = S, Ar = 2,4-Cl2C6H3): white
solid; yield, 74%; mp, 190.2−191.3 °C; IR (KBr) ν 3348 (NH), 2955
(ArH), 1584, 1546 (Ar), 1352 (PO), 1287, 1178 (POC),
1
1051, 1033 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.12
(t, J = 7.2 Hz, 3H, CH3), 1.24 (t, J = 7.2 Hz, 3H, CH3), 3.63 (s, 6H,
2CH3O), 3.76−3.82 (m, 1H, CH2), 3.91−3.97 (m, 1H, CH2), 4.04−
4.13 (m, 2H, CH2), 5.33 (dd, J = 8.4 Hz, J = 24.6 Hz, 1H, PCH), 5.73
(s, 1H, pyrimidine-H), 5.97 (t, J = 9.0 Hz, 1H, NH), 6.47 (d, J =
7.8 Hz, 1H, ArH), 6.72 (t, J = 7.2 Hz, 1H, ArH), 7.09 (d, J = 8.4 Hz,
1H, ArH), 7.20 (t, J = 8.4 Hz, 1H, ArH), 7.25 (dd, J = 2.4 Hz, J =
8.4 Hz, 1H, ArH), 7.39 (s, 1H, ArH), 7.45 (d, J = 9.0 Hz, 1H, ArH);
31P NMR (CDCl3, 162 MHz) δ 21.69; EI-MS (70 eV) m/z (%) 557.3
(M+, 0.5), 524 (6.1), 523 (5.4), 522 (14.8), 424 (14.2), 423 (14.6),
Data for compound IVj (R = Et, X = S, Ar = 4-BrC6H4): white
solid; yield, 64%; mp, 135.6−136.5 °C; IR (KBr) ν 3363 (NH), 2982
(ArH), 1580, 1557 (Ar), 1366 (PO), 1289, 1190 (POC),
1
1057, 1028 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.14
F
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
a
Table 1. Herbicide Activity of Some Compounds I−III (in Vitro, Plate Method, Inhibition Percent)
compd
Arabidopsis thaliana (10 mg/L)
Poa annua (32 mg/L)
compd
Arabidopsis thaliana (10 mg/L)
Poa annua (32 mg/L)
Is
99
99
0
99
99
0
99
99
0
99
99
99
99
99
99
99
0
99
IIIb
IIIc
IIId
IIIe
IIIf
IIIg
IIIh
IIIi
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
It
99
99
99
99
99
99
0
99
99
99
99
99
49
0
Iu
Iv
99
99
99
99
0
99
99
99
99
0
99
99
99
99
0
Iw
Ix
IIa
IIb
IIIa
0
99
99
99
0
0
0
IIIj
a
Each sample was tested against each plant three times.
a b
,
Table 2. Herbicide Activity of Some Compounds I−IV (in Vivo, Glass House Screen, GH1)
postemergence
pre-emergence
dopse
(g/ha)
Amaranthus
retroflexus
Lolium
perenne
Stellaria
media
Digitaria
sanguinalis
Amaranthus
retroflexus
Lolium
perenne
Stellaria
media
Digitaria
sanguinalis
compd
symptomology
Ib
Ic
If
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
750
100
100
70
80
80
60
80
70
60
70
30
0
80
80
40
80
70
60
60
40
0
80
70
40
60
60
60
70
20
0
80
70
30
80
70
70
70
70
0
80
70
20
90
50
40
70
0
60
80
0
70
60
0
ST
NC
ST
NC
NC
ST
ST
Ig
Ii
100
100
90
50
10
40
60
0
70
20
30
20
0
NC
ST
NC
NC
NC
ST
Ik
CL
CL
MR
In
90
Ip
70
Iq
0
0
0
0
Is
100
90
100
100
60
20
20
20
0
70
80
40
50
20
20
0
80
80
50
0
80
70
70
70
20
60
0
80
80
60
20
0
40
70
30
40
0
50
90
30
0
NC
NC
ST
BL
ST
CL
ST
NC
ST
DG
ST
GI
It
Iu
90
Iv
100
70
NC
CL
BL
Iw
0
0
Ix
70
40
0
60
0
40
0
60
0
IIIa
30
MR
GI
acetochlor
atrazine
glyphosate
mesotrione
40
70
100
100
80
90
90
90
100
70
80
100
100
100
100
40
100
100
100
100
70
90
100
90
100
100
50
10
100
1000
1000
250
100
100
100
NC
NC
BL
ST
NC
a
Scores are given as percent phytotoxicity score. The higher the score (% phytotoxicity), the greater the efficacy of the compound. Herbicide
symptomologies are given as a phytotoxicity type: NC, necrosis; ST, stunting; GI, germination inhibition; CL, chlorosis; DG, darker green; BL,
b
bleaching. Compounds II−IV displayed no herbicidal activity in the GH1 bioassay screening.
422 (70.4), 421 (21.6), 420 (100), 384 (5.8). Anal. Calcd for
C23H26Cl2N3O5PS: C, 49.47; H, 4.69; N, 7.52. Found: C, 49.33; H,
4.40; N, 7.73.
1.18 (t, J = 7.2 Hz, 3H, CH3), 3.66−3.74 (m, 1H, CH2), 3.80 (s, 6H,
2CH3O), 3.88−4.06 (m, 3H, CH2), 4.77 (d, J = 24.0 Hz, 1H, PCH),
5.04 (br s, 1H, NH), 5.79 (s, 1H, pyrimidine-H), 6.54 (d, J = 8.0 Hz,
1H, ArH), 6.69 (t, J = 7.6 Hz, 1H, ArH), 6.95 (t, J = 7.6 Hz, 1H, ArH),
7.05 (d, J = 8.0 Hz, 1H, ArH), 7.24−7.30 (m, 3H, ArH), 7.40 (d, J =
7.6 Hz, 2H, ArH); 31P NMR (CDCl3, 162 MHz) δ 21.03. Anal. Calcd
for C23H28N3O6P: C, 58.35; H, 5.96; N, 8.88. Found: C, 58.51; H,
6.07; N, 9.00.
Data for compound IVo (R = Et, X = S, Ar = 4-HOC6H4): white
solid; yield, 75%; mp, 201.3−202.5 °C; IR (KBr) ν 3365 (NH), 2987
(ArH), 1573, 1559 (Ar), 1361 (PO), 1284, 1183 (POC),
1
1056, 1034 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.15
(t, J = 7.2 Hz, 3H, CH3), 1.18 (t, J = 7.2 Hz, 3H, CH3), 3.63 (s, 6H,
2CH3O), 3.71−3.74 (m, 1H, CH2), 3.78−3.83 (m, 1H, CH2), 3.89−
4.03 (m, 2H, CH2), 4.71 (dd, J = 7.8 Hz, J = 24.0 Hz, 1H, PCH), 5.70
(s, 1H, pyrimidine-H), 5.78 (t, J = 8.4 Hz, 1H, NH), 6.50 (d, J =
8.4 Hz, 1H, ArH), 6.56 (d, J = 8.4 Hz, 2H, ArH), 6.69 (t, J = 7.2 Hz,
1H, ArH), 7.07 (d, J = 8.4 Hz, 2H, ArH), 7.16 (t, J = 7.8 Hz, 1H,
ArH), 7.45 (d, J = 7.8 Hz, 1H, ArH), 7.96 (br s, 1H, OH); 31P NMR
(CDCl3, 162 MHz) δ 22.79; EI-MS (70 eV) m/z (%) 505.3 (M+, 5.0),
370 (9.1), 369 (22.5), 368 (100), 274 (10.9), 263 (6.1), 230 (15.3),
228 (23.4), 196 (5.7). Anal. Calcd for C23H28N3O6PS: C, 54.65; H,
5.58; N, 8.31. Found: C, 54.50; H, 5.74; N, 8.57.
Data for compound IVq (R = Et, X = O, Ar = 2-ClC6H4): white
solid; yield, 85%; mp, 90.5−91.3 °C; IR (KBr) ν 3353 (NH), 2981
(ArH), 1563, 1547 (Ar), 1351 (PO), 1277, 1169 (POC),
1
1042, 1021 (COC) cm−1; H NMR (CDCl3, 600 MHz) δ 1.06
(t, J = 7.2 Hz, 3H, CH3), 1.24 (t, J = 7.2 Hz, 3H, CH3), 3.64−3.71 (m,
1H, CH2), 3.79 (s, 6H, 2CH3O), 3.86−3.92 (m, 1H, CH2), 4.05−4.14
(m, 2H, CH2), 5.19 (t, J = 9.0 Hz, 1H, NH), 5.39 (dd, J = 9.0 Hz, J =
24.6 Hz, 1H, PCH), 5.79 (s, 1H, pyrimidine-H), 6.56 (d, J = 8.4 Hz,
1H, ArH), 6.69 (t, J = 7.8 Hz, 1H, ArH), 6.98 (t, J = 7.8 Hz, 1H, ArH),
7.04 (d, J = 7.8 Hz, 1H, ArH), 7.17 (q, J = 7.2 Hz, 2H, ArH), 7.36 (d,
J = 7.2 Hz, 1H, ArH), 7.45 (d, J = 7.2 Hz, 1H, ArH); 31P NMR
(CDCl3, 162 MHz) δ 20.78; EI-MS (70 eV) m/z (%) 507.5 (M+, 4.8),
370.5 (100), 336 (4.0), 232 (5.9), 136 (6.7). Anal. Calcd for
Data for compound IVp (R = Et, X = O, Ar = C6H5): light yellow
oil; yield, 68%; IR (KBr) ν 3371 (NH), 2984 (ArH), 1570, 1552
(Ar), 1357 (PO), 1280, 1175 (POC), 1046, 1023 (COC)
1
cm−1; H NMR (CDCl3, 400 MHz) δ 1.09 (t, J = 7.2 Hz, 3H, CH3),
G
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
C23H27ClN3O6P: C, 54.39; H, 5.36; N, 8.27. Found: C, 54.41; H, 5.50;
N, 8.08.
Data for compound IVr (R = Et, X = O, Ar = 2-FC6H4): light
yellow oil; yield, 73%; IR (KBr) ν 3364 (NH), 2988 (ArH), 1560,
1542 (Ar), 1357 (PO), 1270, 1173 (POC), 1048, 1026 (C
OC) cm−1; 1H NMR (CDCl3, 400 MHz) δ 1.09 (t, J = 6.8 Hz, 3H,
CH3), 1.23 (t, J = 6.8 Hz, 3H, CH3), 3.65−3.72 (m, 1H, CH2), 3.78 (s,
6H, 2CH3O), 3.87−3.97 (m, 1H, CH2), 4.04−4.13 (m, 2H, CH2),
5.07 (t, J = 6.8 Hz, 1H, NH), 5.20 (dd, J = 8.0 Hz, J = 24.4 Hz, 1H,
PCH), 5.78 (s, 1H, pyrimidine-H), 6.63 (d, J = 8.0 Hz, 1H, ArH), 6.71
(t, J = 7.6 Hz, 1H, ArH), 6.80 (d, J = 7.6 Hz, 1H, ArH), 6.91 (d, J =
7.6 Hz, 1H, ArH), 7.04 (q, J = 7.2 Hz, 2H, ArH), 7.22 (d, J = 7.2 Hz,
1H, ArH), 7.40 (t, J = 7.2 Hz, 1H, ArH); 31P NMR (CDCl3, 162
MHz) δ 20.34. Anal. Calcd for C23H27FN3O6P: C, 56.21; H, 5.54; N,
8.55. Found: C, 56.37; H, 5.34; N, 8.31.
Data for compound IVs (R = Et, X = O, Ar = 4-FC6H4): light
yellow oil; yield, 75%; IR (KBr) ν 3353 (NH), 2972 (ArH), 1553,
1547 (Ar), 1351 (PO), 1267, 1169 (POC), 1052, 1029 (C
OC) cm−1; 1H NMR (CDCl3, 400 MHz) δ 1.12 (t, J = 6.8 Hz, 3H,
CH3), 1.18 (t, J = 6.8 Hz, 3H, CH3), 3.80 (s, 6H, 2CH3O), 3.91−4.06
(m, 4H, CH2), 4.77 (dd, J = 6.4 Hz, J = 24.0 Hz, 1H, PCH), 5.02 (t,
J = 8.0 Hz, 1H, NH), 5.80 (s, 1H, pyrimidine-H), 6.51 (d, J = 8.0 Hz,
1H, ArH), 6.71 (t, J = 7.6 Hz, 1H, ArH), 6.94−7.01 (m, 3H, ArH),
7.07 (d, J = 7.6 Hz, 1H, ArH), 7.39 (t, J = 7.6 Hz, 2H, ArH); 31P NMR
(CDCl3, 162 MHz) δ 20.18. Anal. Calcd for C23H27FN3O6P: C, 56.21;
H, 5.54; N, 8.55. Found: C, 56.04; H, 5.48; N, 8.63.
Data for compound IVt (R = Et, X = O, Ar = 4-ClC6H4): light
yellow oil; yield, 79%; IR (KBr) ν 3356 (NH), 2979 (ArH), 1567,
1543 (Ar), 1359 (PO), 1272, 1161 (POC), 1045, 1028 (C
OC) cm−1; 1H NMR (CDCl3, 400 MHz) δ 1.13 (t, J = 7.2 Hz, 3H,
CH3), 1.19 (t, J = 6.8 Hz, 3H, CH3), 3.81 (s, 6H, 2CH3O), 3.90−4.06
(m, 4H, CH2), 4.75 (d, J = 24.4 Hz, 1H, PCH), 4.98 (br s, 1H, NH),
5.80 (s, 1H, pyrimidine-H), 6.49 (d, J = 8.0 Hz, 1H, ArH), 6.71 (t, J =
7.6 Hz, 1H, ArH), 6.95 (t, J = 7.6 Hz, 1H, ArH), 7.07 (d, J = 7.6 Hz,
1H, ArH), 7.25 (d, J = 8.0 Hz, 2H, ArH), 7.35 (d, J = 6.4 Hz, 2H,
ArH); 31P NMR (CDCl3, 162 MHz) δ 20.92. Anal. Calcd for
C23H27ClN3O6P: C, 54.39; H, 5.36; N, 8.27. Found: C, 54.13; H, 5.31;
N, 8.33.
Data for compound IVu (R = Et, X = O, Ar = 4-CH3C6H4): light
yellow oil; yield, 66%; IR (KBr) ν 3341 (NH), 2994 (ArH), 1573,
1560, 1497 (Ar), 1362 (PO), 1271, 1177 (POC), 1047, 1026
(COC) cm−1; 1H NMR (CDCl3, 600 MHz) δ 1.10 (t, J = 6.6 Hz,
3H, CH3), 1.17 (t, J = 6.6 Hz, 3H, CH3), 2.28 (s, 3H, CH3), 3.65−3.73
(m, 1H, CH2), 3.78 (s, 6H, 2CH3O), 3.87−3.95 (m, 2H, CH2), 3.98−
4.03 (m, 1H, CH2), 4.75 (d, J = 24.0 Hz, 1H, PCH), 5.68 (br s, 1H,
NH), 5.78 (s, 1H, pyrimidine-H), 6.55 (d, J = 7.8 Hz, 1H, ArH), 6.67
(t, J = 7.2 Hz, 1H, ArH), 6.93 (t, J = 7.8 Hz, 1H, ArH), 7.04 (d, J = 7.8
Hz, 1H, ArH), 7.07 (d, J = 7.2 Hz, 2H, ArH), 7.27 (d, J = 7.2 Hz, 2H,
ArH); 31P NMR (CDCl3, 162 MHz) δ 21.25; EI-MS (70 eV) m/z (%)
487.3 (M+, 4.8), 351 (24.2), 350 (100), 258 (4.2), 210 (15.8). Anal.
Calcd for C24H30N3O6P: C, 59.13; H, 6.20; N, 8.62. Found: C, 59.31;
H, 6.28; N, 8.50.
Data for compound IVv (R = Et, X = O, Ar = 4-NO2C6H4): white
solid; yield, 64%; mp, 115.4−117.3 °C; IR (KBr) ν 3362 (NH), 2999
(ArH), 1570, 1564, 1492 (Ar), 1357 (PO), 1266, 1171 (PO
1
C), 1046, 1028 (COC) cm−1; H NMR (CDCl3, 600 MHz)
δ 1.16 (t, J = 7.2 Hz, 3H, CH3), 1.20 (t, J = 7.2 Hz, 3H, CH3), 3.80 (s,
6H, 2CH3O), 3.83−3.88 (m, 1H, CH2), 3.98−4.04 (m, 3H, CH2),
4.88 (dd, J = 6.6 Hz, J = 25.2 Hz, 1H, PCH), 5.08 (t, J = 7.8 Hz, 1H,
NH), 5.82 (s, 1H, pyrimidine-H), 6.40 (d, J = 7.8 Hz, 1H, ArH), 6.75
(t, J = 7.8 Hz, 1H, ArH), 6.95 (t, J = 7.8 Hz, 1H, ArH), 7.10 (d, J =
7.8 Hz, 1H, ArH), 7.61 (d, J = 7.2 Hz, 2H, ArH), 7.16 (d, J = 7.2 Hz,
2H, ArH); 31P NMR (CDCl3, 162 MHz) δ 21.03. Anal. Calcd for
C24H27N4O8P: C, 53.28; H, 5.25; N, 10.81. Found: C, 53.17; H, 5.35;
N, 10.98.
Herbicidal Activity Assays. All of the herbicidal activity assays (in
vitro and in vivo) were performed in the bioactive activity evaluation
platform at Syngenta Jealott’s Hill International Research Centre.
Herbicidal Plate Assays (in Vitro). The compounds were tested
for herbicidal activity against Arabidopsis thaliana at 10 mg/L and
H
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
Table 4. Insecticidal Activity of Compounds IVs, IVt, and IVl
Aphis species (mixed-population mortality,
Plutella xylostella (larval mortality,
500 mg/L)
Diabrotica balteata (larval mortality,
500 mg/L)
1000 mg/L)
compd
Rep1
Rep2
Rep3
av
Rep1
Rep2 Rep3
av
Rep1
Rep2
Re p 3
av
IVs
IVt
IVl
0
99
0
99
99
0
99
99
0
66
99
0
0
0
0
0
0
0
0
0
0
0
0
99
0
0
0
0
33
0
99
0
99
0
99
0
99
0
0
0
thiamethoxam
indoxacarb
99
0
99
0
99
0
99
0
99
99
99
99
99
99
99
99
99
99
99
99
against Poa annua at 32 mg/L. Test plates were stored for 7 days in a
controlled environment cabinet. They were scored as 0 or 99, where
99 means significant herbicidal effect and 0 means no effect. The
herbicidal activity is summarized in Table 1.
that these compounds perhaps have novel herbicidal modes of action.
Further herbicidal mode of action determination is underway at
Syngenta Jealott’s Hill International Research Centre.
Herbicide Glasshouse Screening (in Vivo, GH1). The
substances were dissolved in dimethyl sulfoxide (DMSO) for storage.
Subsamples to be tested were dried down and formulated into spray
solution for application. The compounds were tested for pre- and
postemergence activity against four weed species, with the compounds
applied at 1000 g/ha. The plants were then stored in the glasshouse
for 12 days. The weeds tested were Amaranthus retroflexus, Stellaria
media, Lolium perenne, and Digitaria sanguinalis. Assessments were
made of pecent phytotoxicity and converted to a banded score
between 0 and 100, where complete control of the target is 100 and
0 is no control. Acetochlor, atrazine, mesotrione, and glyphosate were
used as positive controls for the test. The herbicidal activity is
summarized in Table 2.
Herbicide Glasshouse Screening (in Vivo, GH2). The
substances were dissolved in DMSO for storage. Subsamples to be
tested were dried down and formulated into spray solution for
application. The compounds were tested for pre- and postemergence
activity against a range of weed species (dicotolydon plant weeds
Chenopodium album, Abutalon theophrasti, Koschia scoparia, and Bidens
pilosa; monocotolydon plant weeds Echinochloa crus-galli, Setaria
fabari, Eleusine indica, and Sorghum halapense), with the compounds
applied at 1000 g/ha. The plants were then stored in the glasshouse
for 12 days. Assessments were made of percent phytotoxicity and
converted to a banded score between 0 and 100, where complete
control of the target is 100 and 0 is no control. Acetochlor, atrazine,
mesotrione, and glyphosate were used as positive controls for the test.
The herbicidal activity is summarized in Table 3.
RESULTS AND DISCUSSION
■
Synthesis. Series of novel α-amino phosphonate derivatives
containing a pyrimidinyl moiety, I, II, III, and IV, were
designed and synthesized by Lewis acid (magnesium
perchlorate) catalyzed Mannich-type reaction of benzoaldehyde
containing a pyrimidinyl group, substituted benzylamine, and
phosphites. It was found that Lewis acid (magnesium
perchlorate) has a large effect on the rate of the reaction and
yields of products; without the use of the catalyst, the rates of
the reaction were remarkably slowed and the yields were very
low, too (about 20%). The structures of target compounds
I−IV were determined by their spectral data (IR, 1H NMR, 31
NMR, EI-MS, or ESI-MS) and elemental analyses.
P
Herbicidal Activities and Structure−Activity Relation-
ships. The results of herbicidal activities, in vitro and in vivo
(GH1, GH2), of these compounds are listed in Tables 1, 2, and
3, respectively. To our delight, most compounds I exhibited
good herbicidal activities in vivo (Tables 2 and 3). However,
their meta-position and para-position pyrimidin-2-oxy-substi-
tuted structural isomers II and III and their analogues IV did
not display any herbicidal activities in vivo (GH1; data not
listed), although some of them displayed good selectivity
inhibitory activity against Arabidopsis thaliana at a concen-
tration of 10 mg/L in vitro (Table 1).
Insecticide Assays. All of the insecticidal assays were carried out
in the bioactive activity evaluation platform at Syngenta Jealott’s Hill
International Research Centre. The compounds were tested for
activity against an aphid species at 1000 mg/L on a leaf-piece-based
assay and against Plutella xylostella and Diabrotica balteata at 500 mg/L
in artificial diet assays. Chemicals were applied to feeding aphids or
prior to infestation with P. xylostella and D. balteata larvae. Mortality
was assessed relative to control wells using a two-band system (0 or 99
where 99 = significant mortality and 0 = no effect), 3−6 days after the
treatments depending on the assay. In addition to the test compounds,
thiamethoxam and indoxacarb as the positive control compounds were
included in each insecticide assays. For all screens, data were recorded
for replicates and averaged. The insecticidal activity is summarized in
Table 4.
Mode of Action Investigation. Methodology. The mode of
action screen (MOA1) comprises a series of biochemical, cell-based,
and whole plant assays that enable scientists at Syngenta to determine
if test compounds have any of the major herbicide modes of action.
Compounds are tested only once in MOA1 (i.e., there is no duplicate
or replicate), so the IC50 values are just an approximation.
For the in vivo (GH1) herbicidal activity, it was found that
compounds Ib, Ic, Ig, Ii, Is, and Iv displayed 100% inhibition
against Amaranthus retroflexus at the dose of 1000 g/ha in
postemergence treatment. Moreover, both compounds Is and
It showed 100% inhibition against Lolium perenne at the dose of
1000 g/ha in postemergence treatment. Furthermore, all
compounds I exhibited better inhibition against the four plants
tested in postemergence treatment than in pre-emergence one.
Finally, compounds Ib, Ic, Ig, Is, and It displayed good broad-
spectrum herbicidal activities against the four plants in both
post- and pre-emergence treatments. As for the preliminary
structure−activity relationships, it was shown that the different
phosphonic acid esters affected the herbicidal activity
significantly; phosphonic acid methyl and ethyl esters were
universally advantageous for the herbicidal activities compared
with the butyl and phenyl esters. However, the electronic
effects of substituent on the benzene ring have no remarkable
effect on the herbicidal activity. Both electron-donating (Ig,
4-methoxy-substituted) and electron-withdrawing compounds
(Ic, 4-nitro-substituted; Is and It, 4-fluoro-substituted)
displayed as good herbicidal activity; even nonsubstituted
compound Ib also exhibited good herbicidal activity.
Compounds Ib, Ic, Ig, and Ii did not give any specific MOA in
MOA1 as it was inactive in all of the assays; for example, compounds
Ib and Ig did not give any specific MOA in MOA1 as it was inactive in
all of the assays apart from some activity on tobacco cells (EC50
=
1 mg/L, 0.4 mg/L, respectively) and some weak injury on Arabidospsis
seedlings (EC50 = 36 mg/L, 1 mg/L respectively) and tobacco
seedlings (EC50 = 36 mg/L, 18 mg/L, respectively), so it suggested
As for the in vivo (GH2) herbicidal activity of I, as shown in
Table 3, all of the tested compounds (Ib, Ic, Ig, Ii, Ik, and In)
I
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
Notes
showed better inhibition activity against Chenopodium album
and Kochia scoparia than against the other six plants (Abutilon
theophrasti, Bidens pilosa, Echinochloa crus galli, Setaria faberi,
Eleusine indica, and Sorghum halepense) at the dose of 1000 g/ha
in both post- and pre-emergence treatments; for instance, both
compounds Ig and Ik displayed 100% inhibition against
Chenopodium album in the postemergence treatment. However,
these test compounds exhibited weak herbicidal activity against
Bidens pilosa relative to the other seven plants in both post- and
pre-emergence treatments, except for compound Ig, which
displayed 50% inhibition in the pre-emergence treatment.
Further herbicidal activity evaluation in a lower dose and mode
of action investigation are underway at Syngenta Jealott’s Hill
International Research Centre.
Insecticidal Activities. It is worth noting that some of the
analogues IV showed selective insecticidal activities (Table 4),
although compounds IV did not display any herbicidal activities
in vivo. For example, compounds IVs and IVt exhibited
insecticidal activity against Aphis species to some extent at the
concentration of 1000 mg/L. Moreover, the sulfur analogue IVl
showed insecticidal activity against Plutella xylostella at the
concentration of 500 mg/L. Further insecticidal activity study
will be performed and will be reported in due course.
In summary, α-amino phosphonic acids and their ester
derivatives, as bioisosteres of natural amino acids, exhibited
versatile biological activities. To find novel high-activity and
low-toxicity herbicide lead compounds with novel herbicidal
modes of action, four series of novel α-amino phosphonate
derivatives containing a pyrimidinyl moiety I, II, III, and IV
were designed and synthesized by Lewis acid (magnesium
perchlorate) catalyzed Mannich-type reaction of aldehydes,
amines, and phosphites. The bioassay (in vivo, GH1 and GH2)
showed that most compounds I exhibited good selective
herbicidal activities. However, their structural isomers II and III
and analogues IV did not display any herbicidal activities
in vivo, although some of them displayed selectivity inhibitory
activity against Arabidopsis thaliana in vitro. Interestingly,
compounds IVs, IVt, and IVl possessed selective insecticidal
activities against Aphis species or Plutella xylostella, respectively.
Their preliminary herbicidal mode of action and structure−
activity relationships were also investigated.
The authors declare no competing financial interest.
REFERENCES
■
(1) Palacios, F.; Alonso, C.; de los Santos, J. M. Synthesis of α-
aminophosphonates and -phosphinates. Chem. Rev. 2005, 105, 899−
931.
(2) Kuhkar, V. P., Hudson, H. R., Eds. Synthesis of α-Amino-
alkanephosphonic and α-Aminophosphinic Acids [M]; Wiley: Chichester,
UK, 2000.
(3) Montchamp, J.-L. Phosphinate chemistry in the 21st Century: a
viable alternative to the use of phosphorus trichloride in organo-
phosphorus synthesis. Acc. Chem. Res. 2014, 47, 77−87.
́
(4) Crepy, K. V. L; Imamoto, T. New P-chirogenic phosphine ligands
and their use in catalytic asymmetric reactions, new aspects in
phosphorus chemistry III. Curr. Chem. 2003, 223, 1−40.
(5) Tang, W.; Zhang, X. New chiral phosphorus ligands for
enantioselective hydrogenation. Chem. Rev. 2003, 103, 3029−3070.
(6) Cupta, H. C. L. Insecticides: Toxicology and Uses [M]; Agrotech
Publishing Academy Press: Udaipur, India, 1999; 51211.
(7) Matsumara, F. Tocicology of Insecticides [M], 2nd ed.; Plenum
Press: New York, 1985; pp 62−90.
(8) Priestman, M. A.; Healy, M. L.; Becker, A.; Alberg, D. G.; Bartlett,
P. A.; Lushington, G. H.; Schonbrunn, E. Interaction of phosphonate
analogues of the tetrahedral reaction intermediate with 5-enolpyruvyl-
shikimate-3-phosphate synthase in atomic detail. Biochemistry 2005,
44, 3241−3248.
(9) Kafarski, P.; Lejczak, B.; Forlani, G. Herbicidally active
aminomethylenebisphosphonic acids. Heteroat. Chem. 2000, 11,
449−453.
(10) Chen, M. H.; Chen, Z.; Song, B. A.; Bhadury, P. S.; Yang, S.;
Cai, X. J.; Hu, D. Y.; Xue, W.; Zeng, S. Synthesis and antiviral activities
of chiral thiourea derivatives containing α-aminophosphonate moiety.
J. Agric. Food Chem. 2009, 57, 1383−1388.
(11) Hu, D. Y.; Wan, Q. Q.; Yang, S.; Song, B. A.; Bhadury, P. S.; Jin,
L. H.; Yan, K.; Liu, F.; Chen, Z.; Xue, W. Synthesis and antiviral
activities of amide derivatives containing α-aminophosphonate moiety.
J. Agric. Food Chem. 2008, 56, 998−1001.
(12) Long, N.; Cai, X. J.; Song, B. A.; Yang, S.; Chen, Z.; Bhadury, P.
S.; Hu, D. Y.; Jin, L. H.; Xue, W. Synthesis and antiviral activities of
cyanoacrylate derivatives containing an α-aminophosphonate moiety.
J. Agric. Food Chem. 2008, 56, 5242−5246.
(13) Liu, J. Z.; Song, B. A.; Fan, H. T.; Bhadury, P. S.; Wan, W. T.;
Yang, S.; Xu, W. M.; Wu, J.; Jin, L. H.; Xue, W.; Hu, D. Y.; Zeng, S.
Synthesis and in vitro study of pseudo-peptide thioureas containing α-
aminophosphonate moiety as potential antitumor agents. Eur. J. Med.
Chem. 2010, 45, 5108−5112.
(14) Zhang, Y. P.; Bai, S.; Song, B. A.; Bhadury, P. S.; Hu, D. Y.;
Yang, S.; Zhang, X. Y.; Fan, H. T.; Lu, P. Enantioseparation and plant
virucidal bioactivity of new quinazoline derivatives with α-amino-
phosphonate moiety. J. Chromatogr. B: Anal. Technol. Biomed. Life Sci.
2010, 878, 1285−1289.
ASSOCIATED CONTENT
■
S
* Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.jafc.5b02335.
Synthetic procedures for the intermediates and the target
(15) Yang, X.; Song, B. A.; Jin, L. H.; Wei, X.; Bhadury, S. P.; Li, X.
Y.; Yang, S.; Hu, D. Y. Synthesis and antiviral bioactivities of novel
chiral bis-thiourea-type derivatives containing α-aminophosphonate
moiety. Sci. China: Chem. 2011, 54, 103−109.
compounds methods, data of intermediates 1a−1c, 2a−
1
2b, and title compounds I−IV, and H NMR spectra of
I−IV (PDF)
(16) Hoerlein, G. Glufosinate (phosphinothricin), a natural amino
acid with unexpected herbicidal properties. Rev. Environ. Contam.
Toxicol. 1994, 138, 73−145.
AUTHOR INFORMATION
■
Corresponding Author
*(D. Q. SHI) Phone: +86-27-67687958. Fax: +86-27-67862041.
E-mail: chshidq@mail.ccnu.edu.cn.
(17) Baylis, A. D. Why glyphosate is a global herbicide: strengths,
weaknesses and prospects. Pest Manage. Sci. 2000, 56, 299−308.
(18) Forlani, G.; Giberti, S.; Berlicji, Ł.; Petrollino, D.; Kafarski, P.
Analogues of phosphinothricin as inhibitors of plant glutamine
synthetases. J. Agric. Food Chem. 2006, 54, 796−802.
(19) Song, B. A.; Zhang, G. P.; Hu, D. Y.; Pang, L. L.; Yang, S.; Liu,
G.; Wang, H. Preparation of dialkyl 1-(substituted benzothiazol-2-
yl)amino-1-(substituted phenyl)methyl phosphonate derivatives and
their antiviral and antitumor activities. CN Patent 1687088, 2005;
Chem. Abstr. 145, 145879.
Funding
We are grateful to the National Natural Science Foundation of
China (No. 21342004), self-determined research funds of
CCNU from the colleges’ basic research and operation of MOE
(No. CCNU14A02007), and the Syngenta Ph.D. (postgradu-
ate) program for support of this work.
J
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX

Journal of Agricultural and Food Chemistry
Article
(20) Song, B.; Jin, L.; Yang, S.; Bhadury, P. S. Environment-Friendly
Antiviral Agents for Plant [M]; Chemical Industry Press, Beijing, and
Springer-Verlag: Berlin, Germany, 2010.
(21) Forlani, G.; Giberti, S.; Berlicki, L.; Petrollino, D.; Kafarski, P.
Plant P5C reductase as a new target for aminomethylenebi-
sphosphonates. J. Agric. Food Chem. 2007, 55, 4340−4347.
(22) Forlani, G.; Occhipinti, A.; Berlicki, Ł.; Dziedziola, G.;
Wieczorek, A.; Kafarski, P. Tailoring the structure of aminobi-
sphosphonates to target plant P5C reductase. J. Agric. Food Chem.
2008, 56, 3193−3199.
(23) Hirai, K.; Uchida, A.; Ohno, R. Major synthetic routes for
modern herbicide class and agrochemical characteristics [A]. In
Herbicide Classes in Development, Mode of Action, Targets, Genetic
Engineering, Chemistry [M]; Springer-Verlag: Berlin, Germany, 2002;
pp 179−278.
(24) Shimizu, T. Action mechanism of pyrimidinyl carboxy
herbicides. J. Pestic. Sci. 1997, 22 (3), 245−256.
(25) Tamaru, M.; Inoue, J.; Hanai, R. Studies of the new herbicide
KIH-6127.4. Crystal structure of KIH-6127 and quantitative structure-
activity relationship of the iminoxy moiety of KIH-6127 derivatives. J.
Agric. Food Chem. 1997, 45, 2777−2783.
(26) Tamaru, M.; Takehi, T.; Masuyama, N. Studies of the new
herbicide KIH-6127. Part II. Synthesis and herbicidal activity of 6-acyl
pyrimin-2-yl salicylates and analogues against barnyard grass. Pestic. Sci.
1996, 47, 327−335.
(27) Tomlin, C. D. S. The Pesticide Manual, A World Compendium
[M], 14th ed.; British Crop Production Council: Surrey, UK, 2006; p
911.
(28) Lu, L.; Chen, J.; Wu, J.; Ling, W.; Mao, L. S.; Li, M. Z.; Cai, X.;
Peng, W. L.; Wu, Y.; Wu, S. G.; Wang, H. J.; Wang, G. C.; Cui, H.;
Han, S. D.; Qiu, W. L.; Wang, Y. H. Preparation processes and
herbicidal uses of 2-pyrimidinyloxy-N-aryl-benzylamine derivatives.
WO Patent 2002034724, 2002; Chem. Abstr. 136, 355244.
(29) Lu, L.; Chen, J.; Cai, X.; Li, M. Z.; Wu, Y.; Wang, Y. H.
Herbicidal 2-pyrimidyloxy-N-amidophenylbenzyl amine, its prepara-
tion and application. CN Patent 1323788, 2001; Chem. Abstr. 137,
74803.
(30) Wu, J.; Cheng, J.; Lu, L. N-(2-Bromophenyl)-2-(4,6-
dimethoxypyrimidin-2-yloxy)benzylamine, a new selective postemer-
gent herbicide for weed control in winter oilseed rape. J. Agric. Food
Chem. 2006, 54, 5954−5957.
(31) Lima, L. M. A.; Barreiro, E. J. Bioisosterism: a useful strategy for
molecular modification and drug design. Curr. Med. Chem. 2005, 12,
23−49.
(32) Tang, W.; Yu, Z. H.; Shi, D. Q. Synthesis, crystal structure, and
herbicidal activity of pyrimidinyl benzylamine analogues containing a
phosphonyl group. Heteroat. Chem. 2010, 21, 148−155.
K
DOI: 10.1021/acs.jafc.5b02335
J. Agric. Food Chem. XXXX, XXX, XXX−XXX