The synthesis and biological activities of N-(3-pyridylmethyl) N′-(trans-2-thio-4-substitutedphenyl-5,5-4dimethyl-1,3, 2-dioxaphosphinane-2-yl)thioureas

Article abstract of DOI:10.1080/10426500500542968

A series of novel title compounds were synthesized by the addition reaction of trans 2-isothiocyano-4-substitutedphenyl-5, 5-dimethyl-1,3,2- dioxaphosphinane 2-sulfide to 3-aminomethylpyridine or 2-chloro-5-amino methylpyridine. Their structures were conf

Full text of DOI:10.1080/10426500500542968

Phosphorus, Sulfur, and Silicon, 181:1831–1838, 2006
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500500542968
The Synthesis and Biological Activities of N-
(3-pyridylmethyl) N ꢀ-(trans-2-thio-4-substitutedphenyl-
5,5-dimethyl-1,3,2-dioxaphosphinane-2-yl)thioureas
De-Qing Shi
Abudhaim Feras
Y. Hamdan
Yi Liu
Xiao-Song Tan
Key Laboratory of Pesticide and Chemical Biology of Ministry of
Education, College of Chemistry, Central China Normal University,
Wuhan, Hubei, P. R. China
A series of novel title compounds were synthesized by the addition reaction
of trans 2-isothiocyano-4-substitutedphenyl-5, 5-dimethyl-1,3,2-dioxaphosphinane
2-sulfide to 3-aminomethylpyridine or 2-chloro-5-amino methylpyridine. Their
structures were confirmed by 1H NMR, 31P NMR, IR, MS, and elemental analy-
ses. Results of preliminary bioassay showed that all new compounds possess good
fungicidal activity and insecticidal activity to some extent.
Keywords Biological activity; 1,3,2-dioxaphosphinane; substituted pyridine; synthesis;
thiourea
INTRODUCTION
Neonicotinioid insecticides as nicotinic acetylcholine receptor inhibitors
have attracted increasing attention because of their safety, low toxic-
ity, and wide and high activities.1,2 A lot of new insecticides, such as
imidacloprid and acetamiprd, have been commercialized. It was found
that most of the biological active nicotinic compounds contain the 3-
aminomethylpyridine moiety.3 Thiourea derivatives show wide biologi-
cal activities, such as fungicidal, herbicidal, and insecticidal activities;
Received March 1, 2005; accepted September 22, 2005.
We are grateful to the Natural Science Foundation of China (20302002) and the
National Key Project for Basic Research (2003CB114406) for financial support.
Address correspondence to De-Qing Shi, Key Laboratory of Pesticide and Chemical
Biology of Ministry of Education, College of Chemistry, Central China Normal University,
Wuhan, Hubei, 430079, P. R. China. E-mail: chshidq@yahoo.com.cn
1831

1832
D.-Q. Shi et al.
however, because of their weak solubility and penetrate ability in an or-
ganism, phosphoryl thiourea derivatives have attracted many chemists’
interest.4,5 As a continuation of our research work, we designed and
synthesized a number of novel asymmetric cyclophosphorylthiourea
derivatives containing substituted pyridine. The synthetic route is
shown in Scheme 1. Structures of the products were characterized by
1H NMR, 31P NMR, IR, MS, and elemental analyses. Results of the pre-
liminary bioassay showed that the new compounds possess potential
fungicidal activities and insecticidal activities to some extent.
SCHEME 1
RESULTS AND DISCUSSION
The Preparation of the Title Compounds 4
The title compounds 4 were synthesized by the multistep route outlined
in Scheme 1.
Diols
1 react with PSCl3 in the presence of CCl4 as a
solvent to obtain 2-chloro-4-substitutedphenyl-5, 5-dimethyl-1,3,2-
dioxaphosphinane 2-sulfide 2; the ratios of cis and trans isomers
of compounds 2 are 1:1 approximatively,6 2 reacted with potassium
thiocyanate to yield 2-isothiocyano-4-substitutedphenyl-5, 5-dimethyl-
1,3,2-dioxaphosphinane 2-sulfide 3, which are the mixture of cis and
trans isomers. Trans isomers 3 can be obtained by fractional recrys-
tallization with the mixture of ethyl ether and petroleum ether. The
addition reaction of trans isomers 3 to 3-aminomethylpyridine or 2-
chloro-5-aminomethylpyridine yield the trans target products 4.

Synthesis and Biological Activities
1833
Structures and Configuration of the Intermediates
3 and Target Compounds 4
We easily can distinguish trans isomers 2 from cis isomers by the means
of IR and 31P NMR. For IR, the stretching absorption band of the NCS
group in trans isomers usually appears around 1972 cm−1, in contrast to
about 1965 cm−1 for a cis isomer. For 31P NMR spectra, the phosphorus
signal of the cis isomer (45–48 ppm) is downfield relative to that of trans
isomer (36–38 ppm), which can be due to the smaller O-P-O bond angle
in cis isomers.7
1
Structures of target compounds 4 were confirmed by H NMR, 31P
NMR, IR spectra, MS, and elemental analyses.
1
In H NMR spectra, the two methyl protons of 1,3,2-dioxa phosphi-
nane appeared as two singlets, due to the two methyl groups lying in
different magnetic environments. The two methylene protons of 1,3,2-
diaxa phosphinane doublet and multiplicity because of their different
magnetic surroundings and coupling with each other or with the adja-
cent phosphorus atom with the coupling constant of 10.6 Hz and 26 Hz,
respectively; while the 4-position axial proton displayed singlets with-
out coupling with the phosphorus atom. The protons of the methylene
group linking with pyridine appears as multiple peaks. For 31P NMR
spectra, the phosphorus atom of all compounds shows one set of a single
peak, giving chemical shifts about 53 ppm, which is also consist with the
trans configuration of phosphorylthiourea.4 IR spectra of all compounds
showed normal stretching absorption bands, indicating the existence of
the N H (∼3150 cm−1), P S (∼700 cm−1), P O C (∼1000 cm−1), C S
(∼1250 cm−1), and C N (∼1500 cm−1) moiety. The EI mass spectra of
compound 4 revealed the existence of the molecular ion peaks or an-
ticipant fragmentation peaks, which were in good accordance with the
given structures of products.
Biological Activities
Preliminary bioassay results show that these title compounds possess
moderate insecticidal and good fungicidal activities. For example, the
death ratio of Aphis glycine Matsumura by compound 4b, 4c, and 4g
is, respectively, 76.7, 58.3, and 52.4% at the concentration of 2.5 × 10−4
,
while the death ratio of Tetranychus viennensis zacher by compound
4a, 4c, and 4e is, respectively, 41.9, 52.8, and 31.7% at the same
concentration. The fungicidal activities of the target compounds are
listed in Table I. Results show that these compounds are more effec-
tive to Botrytis Cinerea fungi than to other fungi. In the meantime,
the compounds 4a and 4i are more effective to these fungi than other

1834
D.-Q. Shi et al.
TABLE I Fungicidal Activities of Target Compounds 4 (The Plate
Method, C == 50 ppm, Inhibition %)
Fungi Fusarium Rhizoctonia Botrytis Gibberella Botryosphaeria Bopolaris
Kind
oxysporium
solani
cinerea
zeae
berengeriana
maydis
4a
4b
4c
4d
4e
4f
4g
4h
4i
71.43
57.14
57.14
61.90
57.14
61.90
47.62
61.90
66.67
23.81
86.73
79.59
90.82
73.47
77.55
85.71
88.78
92.86
87.76
83.67
100
100
100
84.21
94.74
100
100
100
84.62
57.69
57.69
69.23
46.15
61.54
57.69
76.92
88.46
46.15
85.71
64.29
85.71
78.57
85.71
85.71
92.86
78.57
85.71
71.43
87.50
50.00
75.00
75.00
62.50
62.50
87.50
93.75
87.50
62.50
100
100
4j
compounds. Further structure and activity relationship studies are un-
der way and will be reported in due course.
EXPERIMENTAL
1H NMR and 31P NMR spectra were recorded with a Varian Mercury-
Plus 400 spectrometer with TMS and 85% H3PO4 as the internal and
external reference, respectively, and DMSO-d6 as the solvent, while
mass spectra were obtained with a Finnigan Tracems2000 spectrome-
ter using the EI method. IR spectra were measured by a Nicolet Nexus
470 spectrometer. Elemental analyses were performed with a Elemen-
tar Vario ELIIICHNSO elementary analyzer. Melting points were de-
termined with a WRS-1B digital melting point apparatus, and the ther-
mometer was uncorrected.
Reagents and solvents were available commercially and, purified ac-
cording to conventional methods before use. Diols 1 were prepared ac-
cording to references.10 2-chloro-5-aminomethylpyridine was obtained
in the reported method.11
1. The Synthesis of 2-Chloro-4-Substitutedphenyl-5,
5-Dimethyl-1, 3,2-Dioxaphosphinane 2-Sulfide8
0.01 mol of diol 1, 0.01 mol of PSCl3, and 20 mL of CCl4 were added
to a 50-mL three-necked reaction flask. The mixture was stirred un-
der reflux for 4 h (monitored by TLC). The solvent was removed un-
der reduced pressure, and the residue was dissolved in 25 ml CHCl3,
washed with NaHCO3 solution twice, and then washed with water. The
organic layer was dried over Na2SO4. After removing the solvent under

Synthesis and Biological Activities
1835
a reduced pressure; the crude product was obtained. The ratio of cis
1
and trans isomer of products were determined by H NMR and 31P
NMR.
2. General Procedure for the Synthesis of
2-Isothiocyano-4-substitutedphenyl-5,5-dimethyl-1,3,
2-dioxaphosphinane 2-Sulfide 34
12.5 mmol of compound 2 and 20 mL of anhydrous CH3CN were added
to a 50-mL three-necked flask. Twenty five mmol of KSCN was added
under stirring, and the mixture was heated to 50–60◦C for 20 h. The
solid was filtered. After removing the solvent under reduced pressure,
30 mL of ethyl ether was added. The solid was filtered, and the filtrate
was concentrated to obtain a crude product, which was fractional re-
crystallized with the mixture of ethyl ether and petroleum ether to give
the pure trans compound 3; yield: 36–64%.
3. General Procedure for the Synthesis of N-(3-pyridylmethyl)
N’-(trans-2-thio-4-substitutedphenyl-5,5-dimethyl-1,3,
2-dioxaphosphinane-2-yl) Thioureas 4
Two mmol of trans compound 3 and 10 mL of anhydrous chloroform
were added to a 50-mL flask. Two mmol of 3-aminomethylpyridine
or 2-chloro-5-aminomethylpyridine in 10 mL of anhydrous chloroform
was added dropwise to the reaction mixture. The reaction mixture was
stirred at r.t. for 2–4 h (monitored by TLC). After removing the solvent,
20 mL of anhydrous ethyl ether was added; the solid formed was filtered
and recrystallized by the mixture of ethanol and ethyl ether to give the
pure compound 4.
4a (Ar = phenyl, R = H): white solid, m.p. 168.3–168.7◦, yield 78%; 1H
NMR (DMSO-d6) δ = 0.81 (s, 3H, CH3), 1.10 (s, 3H, CH3), 4.02 (dd, 1H,
2 JH-H = 11.2 Hz, 3 JP-H = 26 Hz, CH2OP), 4.38 (d, 1H, 2 JH-H = 10.0 Hz,
CH2OP), 4.82–4.86 (m, 2H, NCH2), 5.33 (s, 1H, CH-Ar), 7.10–7.13 (m,
1H, β-H on pyridine), 7.26–7.40 (m, 6H, Ar-H + NH), 7.57 (d, 1H,
3 JH-P = 7.6 Hz, γ -H on pyridine), 8.11 (s, 1H, α-H on pyridine), 8.47–
8.50 (m, 1H, α-H on pyridine), 8.53 (s, 1H, NH); 31P NMR (DMSO-d6)
δ = 53.06; Anal. calcd. For C18H22N3O2PS2 (407): C, 53.07; H, 5.41; N,
10.32. Found: C, 53.44; H, 5.68; N, 10.03.
4b (Ar = 3-fluorophenyl, R = H): white solid, m.p. 151.9–152.1◦C,
yield 62%; 1H NMR (DMSO-d6) δ = 0.79 (s, 3H, CH3), 1.06 (s, 3H, CH3),
2
3
4.05 (dd, 1H, JH-H = 10.4 Hz, JP-H = 26 Hz, CH2OP), 4.38 (d, 1H,
2 JH-H = 10.4 Hz, CH2OP), 4.67–4.75 (m, 2H, NCH2), 5.57 (s, 1H, CH-
Ar), 7.12–7.36 (m, 4H, Ar-H + β-H on pyridine), 7.44–7.50 (m, 1H, Ar-H),

1836
D.-Q. Shi et al.
3
7.70 (d, 1H, JH-P = 7.6 Hz, γ -H on pyridine), 8.45–8.47 (m, 1H, α-H
on pyridine), 8.53 (s, 2H, α-H on pyridine + NH), 9.71 (s, 1H, NH);
31P NMR (DMSO-d6) δ = 52.92; MS, m/z (%) 425 (M+, 0.2), 262 (8.1),
162 (22.4), 147 (44.5), 145 (45.0), 132 (60.5), 123 (53.0), 114 (36.5), 108
(100), 94 (47.6), 78 (54.4), 62. (47.1), 54 (64.5), 38 (95.0); Anal. calcd. for
C18H21FN3O2PS2 (425): C, 50.82; H, 4.94; N, 9.88. Found: C, 50.77; H,
5.20; N, 10.15.
4c (Ar = 4-nitrophenyl, R = H): pale yellow solid, m.p. 147.7–148.2◦C,
1
yield 34.7%; H NMR (DMSO-d6) δ = 0.77 (s, 3H, CH3), 0.92 (s, 3H,
2
3
CH3), 4.30 (dd, 1H, JH-H = 10.8 Hz, JP-H = 25.6 Hz, CH2OP), 4.46–
4.76 (m, 3H, NCH2 + CH2OP), 5.58 (s, 1H, CH-Ar), 7.36–7.60 (m, 4H,
Ar-H), 7.73–7.75 (d,1H, 3 JH-P = 8.0 Hz, β-H on pyridine), 7.91–7.93 (d,
1H, 3 JH-P = 6.5 Hz, γ -H on pyridine), 8.22–8.32 (m, 2H, α-H on pyridine
+ NH), 8.46 (s, 1H, α-H on pyridine), 9.61 (s, 1H, NH); 31P NMR (DMSO-
d6) δ = 53.08; Anal. calcd. for C18H21N4O4PS2 (452): C, 47.79; H, 4.65;
N, 12.39. Found: C, 47.51; H, 4.88; N, 12.50.
4d (Ar = 4-chlorophenyl, R = H): white solid, m.p. 165.5–166.1◦C,
1
yield 39.5%; H NMR (DMSO-d6) δ = 0.74 (s, 3H, CH3), 1.07 (s, 3H,
2
3
CH3), 4.05 (dd, 1H, JH-H = 11.2 Hz, JP-H = 25.6 Hz, CH2OP), 4.42
(d, 1H, 2 JH-H = 10.4 Hz, CH2OP), 4.69–4.75 (m, 2H, NCH2), 5.55 (s, 1H,
CH-Ar), 7.34 (d, 2H, 3 JH-H = 8.4 Hz, Ar-H), 7.49 (d, 2H, 3 JH-H = 8.0 Hz,
3
Ar-H), 7.70 (d, 1H, JH-H = 7.2 Hz, β-H on pyridine), 8.46 (d, 2H,
3 JH-H = 4.8 Hz, α-H, γ -H on pyridine), 8.53 (s, 1H, α-H on pyridine), 9.67
(s, 1H, NH); 31P NMR (DMSO-d6) δ = 53.01; IR (KBr) (υmax/cm−1) 3260
(N-H), 1509 (C=N), 653 (P=S), 1013 and 982 (P O C), 1266 (C=S); MS,
m/z (%) 443 (M + 2, 4), 441 (M+, 7.6), 335 (17), 333 (41.8), 280 (31.3),
278 (67.3), 142 (19.9), 138 (26.9), 136 (25.8), 124 (16.4), 110 (19.6), 89
(22.8), 78 (34.2), 62 (28.3), 55 (45.0), 40 (100), 38 (86.8); Anal. calcd. for
C18H21ClN3O2PS2 (441.5): C, 48.92; H, 4.76; N, 9.51. Found: C, 48.81;
H, 4.54; N, 9.25.
4e (Ar = 2-chlorophenyl, R = H): pale yellow solid, m.p. 140.3–
141.7◦C, yield 44%; 1H NMR (DMSO-d6) δ = 0.76 (s, 3H, CH3),
2
3
1.07 (s, 3H, CH3), 4.10 (dd, 1H, JH-H = 10.8 Hz, JP-H = 26.2 Hz,
2
CH2OP), 4.53 (d, 1H, JH-H = 10.8 Hz, CH2OP), 4.85 (s, 2H, NCH2),
5.95 (s, 1H, CH-Ar), 7.35–7.50 (m, 5H, Ar-H + β-H on pyri-
3
dine), 8.23 (m, 1H, JH-H = 6.2 Hz, γ -H on pyridine), 8.67–8.75
(m, 2H, α-H on pyridine), 8.99 (s, 1H, NH), 10.17 (s, 1H, NH);
IR (KBr) (υmax/cm−1) 3178 (N H), 1509 (C=N), 672 (P=S), 1035
and 987 (P O C), 1218 (C=S); MS, m/z (%) 443 (M + 2, 1.9), 441
(M+, 2.5), 382 (7.7), 298 (12.2), 142 (18.0), 138 (23.3), 114 (34.7),
95 (19.4), 89 (21.7), 78 (19.6), 75 (18.3), 62 (46.3), 54 (66.9), 40 (100);
Anal. calcd. for C18H21ClN3O2PS2 (441.5): C, 48.92; H, 4.76; N, 9.51.
Found: C, 48.67; H, 4.98; N, 9.73.

Synthesis and Biological Activities
1837
4f (Ar = phenyl, R = Cl): yellow solid, m.p. 153.6–155.3◦C, yield
72%; 1H NMR (DMSO-d6) δ = 0.74 (s, 3H, CH3), 0.98 (s, 3H, CH3),
3
2
4.05 (dd, 1H, JH-P = 10.6 Hz, JH-H = 26 Hz, CH2OP), 4.41 (d, 1H,
2 JH-H = 10.8 Hz, CH2OP), 4.70–4.74 (m, 2H, NCH2), 5.55 (s, 1H, CH-
3
Ar), 7.31 (d, 1H, JH-H = 7.2 Hz, γ -H on pyridine), 7.37–7.47 (m, 5H,
Ar-H), 7.76 (d, 1H, 3 JH-H = 6.0 Hz, β-H on pyridine), 8.36 (s, 1H, α-H on
pyridine), 8.48 (s, 1H, NH), 9.74 (d, 1H, 3 JH-H = 10.0 Hz, NH); 31PNMR
(DMSO-d6) δ = 52.96; Anal. calcd. for C18H21ClN3O2PS2 (441.5): C,
48.92; H, 4.76; N, 9.51. Found: C, 49.24; H, 4.93; N, 9.39.
4g (Ar = 3-fluorophenyl, R = Cl): white solid, m.p. 136.2–137.0◦C,
yield 86%; 1H NMR (DMSO-d6) δ = 0.77 (s, 3H, CH3), 0.97 (s, 3H, CH3),
2
3
4.01–4.10 (dd, 1H, JH-H = 10.8 Hz, JP-H = 25.6 Hz, CH2OP), 4.41 (d,
2
1H, JH-H = 10.8 Hz, CH2OP), 4.65–4.78 (m, 2H, NCH2), 5.55 (s, 1H,
CH-Ar), 7.12–7.25 (m, 3H, Ar-H), 7.45–7.50 (m, 1H, Ar-H), 7.64 (d, 1H,
3 JH-H = 8.0 Hz, γ -H on pyridine), 7.97 (d, 1H, 3 JH-H = 10.0 Hz, β-H on
pyridine), 8.58 (s, 1H, α-H on pyridine), 8.59 (s, 1H, NH), 9.85 (s, 1H,
NH); 31P NMR (DMSO-d6) δ = 52.94; IR (KBr) (υmax/cm−1) 3133 (N H),
1459 (C N), 696 (P S), 1020 and 981 (P O C), 1173 (C S); MS, m/z
(%) 459.2 (M+, 0.9), 317 (44.5), 261 (100), 161 (40.5), 145 (22.8), 134
(27.8), 113 (24.7), 108 (32.7), 94 (17.8), 78 (15.3), 54 (29.0), 40 (62.3);
Anal. calcd. for C18H20ClFN3O2PS2 (459.5): C, 47.01; H, 4.35; N, 9.14.
Found: C, 46.87; H, 4.23; N, 9.41.
4h (Ar = 4-methylphenyl, R = Cl): white solid, m.p. 141.9–143.1◦C,
yield 30%; 1H NMR (DMSO-d6) δ = 0.72 (s, 3H, CH3), 0.97 (s, 3H, CH3),
2
3
2.32 (s, 3H, CH3-Ar), 4.04 (dd, 1H, JH-H = 10.4 Hz, JP-H = 26.2 Hz,
2
CH2OP), 4.39 (d, 1H, JH-H = 10.8 Hz, CH2OP), 4.69–4.74 (m, 2H,
NCH2), 5.46 (s, 1H, CH-Ar), 7.18–7.23 (m, 4H, Ar-H), 7.45 (d, 1H,
3 JH-H = 8.0 Hz, γ -H on pyridine), 7.77 (d, 1H, JH-H = 6.0 Hz, β-H on
3
3
pyridine), 8.35 (s, 1H, α-H on pyridine), 8.48 (d, 1H, JH-H = 8.4 Hz,
NH), 9.72 (s, 1H, NH); 31PNMR (DMSO-d6) δ = 53.01; MS, m/z (%)
422 (1.8), 382 (5.0), 376 (15.5), 294 (100), 283 (10.4), 256 (45.7),
134 (14.6), 104 (30.4), 90 (35.8), 76 (32.6), 62 (31.2); Anal. calcd. for
C19H23ClN3O2PS2 (455.5): C, 50.05; H, 5.05; N, 9.22. Found: C, 49.96; H,
4.81; N, 9.18.
4i (Ar = 4-chlorophenyl, R = Cl): yellow solid, m.p. 150.4–151.1◦C,
yield 43%; 1H NMR (DMSO-d6) δ = 0.74 (s, 3H, CH3), 0.96 (s, 3H, CH3),
2
3
4.07 (dd, 1H, JH-H = 10.8 Hz, JP-H = 25.6 Hz, CH2OP), 4.39 (d, 1H,
2 JH-H = 10.8 Hz, CH2OP), 4.69–4.75 (m, 2H, NCH2), 5.53 (s, 1H, CH-
Ar), 7.34 (d, 2H,3 JH-H = 8.4 Hz, Ar-H), 7.46–7.51 (m, 3H, Ar-H + γ -H on
pyridine), 7.77 (d, 1H, 3 JH-H = 8.4 Hz, β-H on pyridine), 8.36 (s, 1H, α-H
on pyridine), 8.50 (s, 1H, NH), 9.76 (d, 1H, 3 JH-H = 11.2 Hz, NH); Anal.
calcd. for C18H20Cl2N3O2PS2 (476): C, 45.38; H, 4.20; N, 8.82. Found:
C, 45.55; H, 4.11; N, 9.07.

1838
D.-Q. Shi et al.
4j (Ar = 2, 4-dichlorophenyl, R = Cl): white solid, m.p. 124.6–125.3◦C,
yield 45%; 1H NMR (DMSO-d6) δ = 0.75 (s, 3H, CH3), 1.06 (s, 3H, CH3),
2
3
4.10 (dd, 1H, JH-H = 10.6 Hz, JP-H = 26 Hz, CH2OP), 4.35–4.37 (m,
3
1H, CH2OP), 4.72 (d, 2H, JH-H = 6.0 Hz, NCH2), 5.36 (s, 1H, CH-Ar),
7.38–7.75 (m, 3H, Ar-H), 7.96 (d, 1H, 3 JH-H = 9.2 Hz, γ -H on pyridine),
3
8.08 (d, 1H, JH-H = 10.4 Hz, β-H on pyridine), 8.32 (s, 1H, α-H on
pyridine), 8.50 (s, 1H, NH), 9.62 (s, 1H, NH); MS, m/z (%) 427 (6.1), 227
(4.3), 165 (2.6), 154 (15.0), 130 (8.5), 128 (9.7), 119 (10.2), 106 (9.0), 90
(100), 63 (10.4), 39 (81.0); Anal. calcd. for C18H19Cl3N3O2PS2 (510.5):
C, 42.31; H, 3.72; N, 8.23. Found: C, 42.19; H, 3.90; N, 8.54.
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