Synthesis and antiviral bioactivities of novel chiral bis-thiourea-type derivatives containing α-aminophosphonate moiety

Article abstract of DOI:10.1007/s11426-010-4179-5

Starting from 1-((1R,2R)-2-aminocyclohexyl)-3-substituted thioureas (3a-c) and substituted isothiocyanates (9a-d), chiral bis-thiourea derivatives containing α-aminophosphonate moiety 10a-l were prepared and completely characterized by elemental analysis, physical and spectral (IR, ¹H NMR, ¹³C NMR, ³¹P NMR) data. The results of bioassay revealed that compounds 10a and 10e possessed appreciable curative bioactivities on cucumber mosaic virus (CMV) at 0.5 mg/mL in vivo (inhibitory rate = 60.3%, 64.8% respectively) and tobacco mosaic virus (TMV) at 0.5 mg/mL in vivo (inhibitory rate = 50.3%, 50.8% respectively), which were comparable to the values shown by standard reference (58.7%) and commercial product Ningnanmycin (56.3%), respectively. Chiral compound 10e displayed more potent antiviral activity (EC₅₀ = 0.149 mg/mL) than Ningnanmycin (EC₅₀ = 0.201mg/mL) against CMV.

Full text of DOI:10.1007/s11426-010-4179-5

SCIENCE CHINA
Chemistry
January 2011 Vol.54 No.1: 103–109
doi: 10.1007/s11426-010-4179-5
• ARTICLES •
· SPECIAL TOPIC · The Frontiers of Chemical Biology and Synthesis
Synthesis and antiviral bioactivities of novel chiral bis-thiourea-type
derivatives containing -aminophosphonate moiety
YANG Xuan1, SONG BaoAn1*, JIN LinHong1, WEI Xue1, BHADURY S Pinaki1,
LI XiangYang1, YANG Song2* & HU DeYu2
1Key Laboratory of Green Pesticide and Agricultural Bioengineering of Ministry of Education; Guizhou University, Guiyang 550025, China
2National and Local Jointed Engineering Laboratory for Biomass Comprehensive Utilization, Guizhou University, Guiyang 550025, China
Received March 11, 2010; accepted September 24, 2010
Starting from 1-((1R,2R)-2-aminocyclohexyl)-3-substituted thioureas (3a–c) and substituted isothiocyanates (9a–d), chiral
bis-thiourea derivatives containing -aminophosphonate moiety 10a–l were prepared and completely characterized by ele-
1
mental analysis, physical and spectral (IR, H NMR, 13C NMR, 31P NMR) data. The results of bioassay revealed that com-
pounds 10a and 10e possessed appreciable curative bioactivities on cucumber mosaic virus (CMV) at 0.5 mg/mL in vivo (in-
hibitory rate = 60.3%, 64.8% respectively) and tobacco mosaic virus (TMV) at 0.5 mg/mL in vivo (inhibitory rate = 50.3%,
50.8% respectively), which were comparable to the values shown by standard reference (58.7%) and commercial product
Ningnanmycin (56.3%), respectively. Chiral compound 10e displayed more potent antiviral activity (EC50 = 0.149 mg/mL)
than Ningnanmycin (EC50 = 0.201mg/mL) against CMV.
chiral bis-thiourea, -aminophosphonate moiety, antiviral activity, synthesis
nanmycin for the field trial is largely limited due to its
1 Introduction
sensitivity towards moisture and light. Therefore, the search
for new antiplant viral agents still remains as one of the
most important tasks in pesticide science [1].
The plant virus disease, often considered as plant cancer,
has long been a challenging problem to control in the agri-
cultural sector. The cucumber mosaic virus (CMV) and to-
bacco mosaic virus (TMV) pose serious threats to the pro-
duction of crop throughout the world. The application of
traditional pesticides with high residue level and negative
impact on the environment has not proved effective to en-
hance productivity. Ningnanmycin is a commercial antiviral
agent first isolated from Strepcomces noursei var·xichan-
gensisn. Var. by the Chengdu Institute of Biology, the
Chinese Academy of Sciences. It is a type of microbial
pesticide, which can enhance resistance in host plants by
destruction of coat protein of TMV. Despite being useful in
the treatment of plants affected by TMV, the use of Ning-
The application of thiourea derivatives as potential fun-
gicides, herbicides, rodenticides, as well as anti-bacterial,
anti-plant viral and anti-microbial therapeutic agents has
been reported since early 1950 [2–5]. Selected chiral de-
rivatives of these compounds are also applied in typical
organocatalytic asymmetric transformations leading to new
carbon-carbon bond formation [6–9]. Numerous synthetic
studies of aromatic and heterocyclic chiral thioureas were
undertaken in recent years to evaluate their suitability as
non-nucleoside inhibitors (NNRTI) of the reverse transcrip-
tase (RT) enzyme of the human immunodeficiency virus
(HIV-1) [10–14]. Another interesting class of compounds
called -aminophosphonates which are essentially structural
analogues to natural amino acids, exhibit diverse biological
activities such as plant virucidal, plant growth regulatory,
*Corresponding author (email: songbaoan22@yahoo.com, yangsdqj@gmail.com)
© Science China Press and Springer-Verlag Berlin Heidelberg 2011
chem.scichina.com
www.springerlink.com

104
Yang X, et al. Sci China Chem January (2011) Vol.54 No.1
herbicidal, fungicidal and antitumor effects [15–17]. In
view of different biological and chemical applications of
these compounds, development of suitable synthetic meth-
odologies for their preparation in pure form has been a topic
of great interest in the past few decades [18–22]. In order to
incorporate the two aforementioned active pharmacophores
in a single molecule, we prepared a series of chiral mono-
thiourea derivatives containing an -aminophosphonate
moiety by the addition of O,O′-dialkylisothiocyanato(phenyl)
methylphosphonate to a chiral amine. The compounds ex-
hibited a curative activity level close to commercial Ning-
nanmycin against TMV [23]. Since multiple thiourea func-
tionalities can present opportunities for creating more active
compounds through diverse hydrogen-bonded networks, we
studied herein the effect of some novel bis-thiourea deriva-
tives bearing an -aminophosphonate moiety in the design
of new anti-plant viral compounds. The basis for the design
of target compounds and the synthetic route from isothio-
cyanate and diaminocyclohexane are shown in Figure 1 and
Scheme 1 respectively. Preliminary bioassay results showed
that some of these compounds possess a certain degree of
antiviral activity against CMV and TMV at 0.5 mg/mL in
vivo as shown in Table 4. According to the bioassay, com-
pounds 10a and 10e had significant curative bioactivities on
CMV (inhibitory rate = 60.3%, 64.8% respectively) and
TMV (inhibitory rate = 50.3%, 50.8% respectively), which
were comparable to the values shown by standard reference
(58.7%) and commercial product-Ningnanmycin (56.3%).
The chiral compound 10e displayed more potent antiviral
activity (EC50 = 0.149 mg/mL) than Ningnanmycin (EC50 =
0.201 mg/mL) against CMV.
Figure 1 Design of the target compounds.
Compd
10a
10c
10e
10g
R1
Ph
Ph
R2
Et
i-Pr
Et
n-Pr
i-Pr
n-Bu
Compd
10b
10d
10f
10h
10j
R1
Ph
Ph
R2
n-Pr
n-Bu
Et
n-Pr
i-Pr
n-Bu
(R)-1-phenylethyl
(R)-1-phenylethyl
(R)-1-phenylethyl
(R)-1-phenylethyl
(S)-1-phenylethyl
(S)-1-phenylethyl
(S)-1-phenylethyl
(S)-1-phenylethyl
10i
10k
10l
Scheme 1 Synthetic route to chiral bis-thiourea analogues 10a–l containing -aminophosphonate moiety.

Yang X, et al. Sci China Chem January (2011) Vol.54 No.1
105
dropwise the corresponding intermediates 3a–c (1.0 mmol).
The reaction mixture was stirred further for an additional
0.5 h at room temperature, the solvent was removed by
evaporation and the crude product was purified by chroma-
tography on silica using a mixture of petroleum ether and
ethyl acetate (2:1) as the eluent to give compounds 10a–l in
75%–86% yields. The data for 10a is shown below, while
data for 10b–l can be found in the Supporting Information
section.
2 Materials and methods
2.1 Instruments
Melting points were determined on a XT-4 binocular micro-
scope (Beijing Tech Instrument Co., China) and were not
corrected. IR spectra were recorded on a Bruker VECTOR
22 spectrometer in KBr disk. 1H, 13C and 31P NMR (solvent
CDCl3 or D3CCOCD3 or DMSO-d6) spectral analyses were
performed on a JEOL-ECX 500 NMR spectrometer at room
temperature using TMS as an internal standard. Elemental
analyses were performed on an Elementar Vario-III CHN
Data for the title chiral compound 10a
White crystal; mp 199–201 °C; yield, 85%; IR (KBr, cm1):
v 3321, 3289, 3273, 3250, 1552, 1531, 1211, 1020 cm1; 1H
NMR (DMSO-d6, ppm)  9.46 (1H, br, NH), 8.46 (1H, br,
NH), 7.84 (1H, br, NH), 7.48 (1H, br, NH), 7.35 (2H, d, J=
7.5 Hz, ArH), 7.28 (2H, t, J = 7.2 Hz, ArH), 7.22 (1H, t, J=
7.8 Hz, ArH), 7.16 (2H, d, J = 6.9 Hz, ArH), 7.00 (2H, t, J=
7.3 Hz, ArH), 6.93 (1H, t, J = 7.1 Hz, ArH), 6.11 (1H, dd,
J = 9.7, 9.8 Hz, CHP), 4.15 (2H, br, OCH2), 4.03–3.99 (2H,
m, OCH2), 3.92–3.87 (1H, m, CH cycl), 3.82–3.78 (1H, m,
CH cycl), 2.19–2.11 (2H, m, CH2 cycl), 1.64 (2H, br, CH2
cycl), 1.27–1.17 (7H, m, 2 × CH2 cycl + CH3), 1.06 (3H, t,
J = 5.0 Hz, CH3); 13C NMR (125 MHz, DMSO-d6, ppm) 
183.0, 180.0, 139.0, 137.4, 129.2, 128.7, 128.4, 128.0,
124.4, 123.3, 63.2, 62.9, 57.6, 56.6, 55.3, 54.1, 32.7, 31.8,
24.7, 16.8, 16.6; 31P NMR (200 MHz, DMSO-d6, ppm) 
22.4. Anal. calcd for C25H35N4O3PS2: C 56.16, H 6.60, N
10.48; found: C 56.31, H 6.50, N 10.66.
analyzer. Analytical TLC was performed on Silica Gel GF254
.
Column chromatographic purification was carried out using
Silica Gel. GF254. Commercial reagents were used as re-
ceived, unless otherwise indicated. Reactions were per-
formed under a positive pressure of dry argon in oven-dried
or flame-dried glassware equipped with a magnetic stir bar.
Standard inert atmosphere techniques were used in handling
all air and moisture sensitive reagents. Dichloromethane
(DCM) was freshly distilled from calcium hydride (CaH2).
All reagents were of analytical reagent grade or chemically
pure. All solvents were dried, deoxygenated and redistilled
before use.
2.2 Synthetic procedures
Intermediates 1, 2, 4 were purchased from Alfa Aesar. In-
termediates 3 were synthesized by slightly modifying a lit-
erature procedure [24]. Intermediates 5, 6, 7 and 8 were
prepared following standard synthetic protocols [25]. In-
termediates 9 were prepared according to a reported method
[23, 26] with minor modifications of reaction temperature
and reaction time.
2.5 Antiviral biological assay
Purification of tobacco mosaic virus (TMV)
Using Gooding’s method [27], the upper leaves of Nicotiana
tabacum L inoculated with TMV were selected and ground
in a phosphate buffer, then filtered through double layer
pledget. The filtrate was centrifuged at 10000 g, treated
twice with PEG and centrifuged again. The whole experi-
ment was carried out at 4 C. Absorbance values were esti-
mated at 260 nm using an ultraviolet spectrophotometer.
2.3 General procedure for the preparation of the inter-
mediates 3a–c
A 100 mL oven dried round bottom flask containing
(R,R)-1,2-diaminocyclohexane (3.0 mmol) in 15 mL dry DCM
was placed under an atmosphere of dry argon and cooled to
0 °C. Subsequently, a solution of intermediates 2a–c (3.0
mmol) in dry DCM (15 mL) was added dropwise through a
syringe over a period of 4 h. The resulting yellow solution
was left to stir overnight. The reaction mixture was concen-
trated in vacuo and the yellow residue was purified by col-
umn chromatography using a mixture of methanol, CH2Cl2
and ethyl acetate (1:1:1) as the eluent. The data for interme-
diates 3a–c can be found in the Supporting Information.
0.1%, 260 nm
Virus concn  A dilution ratio
E
1 cm


260
Curative effect of compounds against TMV in vivo
Growing leaves of Nicotiana tabacum L of the same ages
were selected. TMV (concentration of 6 × 103 mg/mL) was
dipped to inoculate the whole leaves. Then the leaves were
washed with water and dried. The compound solution was
smeared on the left side and the solvent was smeared on the
right side for control. The local lesion numbers were then
counted and recorded 3–4 d after inoculation [28]. For each
compound, three repetitions were measured. The inhibition
rate of the compound was then calculated according to the
following formula (‘av’ means average).
2.4 General procedure for the preparation of chiral
compounds 10a–l
To a well stirred mixture of intermediates 9a–d (1.0 mmol)
in tetrahydrofuran (10 mL) at room temperature was added

106
Yang X, et al. Sci China Chem January (2011) Vol.54 No.1
dropwise addition of intermediate 2a (3.0 mmol in dry
av local lesion numbers of control
(not treated with compound)
DCM) over different periods of time to a well-stirred solu-
tion of (R,R)-1,2-diaminocyclohexane 1 in dry DCM. It may
be observed from Table 1 that the desired product 3a could
be obtained in 56% yield (Table 1, entry 3) when the
isothiocyanate was added into the mixture over a period of
4 h. Addition of intermediate 2a in one shot and over 2 h
lowered the yield of intermediate 3a to 31% and 44%, re-
spectively (Table 1, entries 1 and 2), whereas increase of
Inhibition rate (%) =
av local lesion numbers of control
(not treated with compound)
av local lesion numbers smeared with drugs

100%
av local lesion numbers of control
(not treated with compound)
Extraction of cucumber mosaic virus (CMV)
The leaves of Nicotiana tabacum L. inoculated with CMV
were selected and ground in phosphate buffer and then fil-
tered through double-layer pledget. The supernatant liquid
obtained after centrifugation of the filtrate at 8000 g was
employed as the virus extract. The entire experiment was
carried out at 4 °C [29].
Table 1 Effect of different rates of addition of isothiocynate 2a on the
synthesis of 3a a)
Preparation of medicaments
Tested compounds and 2% Ningnanmycin aqua used as a
reference antiviral agent were first diluted with a little
amount of N,N-dimethylformamide (DMF) and then the
resulting mixture was dissolved in distilled water containing
1% Tween 20 at 500 g/mL [29].
Entry
Addition period (h)
Yield b) (%)
1
2
3
4
5
6
one shot
31
44
56
54
56
51
2
4
Curative effect of compounds against CMV in vivo
6
Growing leaves of Chenopodium amaranticolor of the same
age were selected. Crude extracts of CMV were dipped and
inoculated with a brush on the whole leaves, which were
previously scattered with silicon carbide. After inoculation,
the leaves were washed with water for 0.5 h and then dried.
The compound solution was smeared on the left side of
leaves, and the solvent was smeared on the right side for
control. All plants were cultivated in an incubator at 28±1 °C
and 10000 Lux illumination. The local lesion numbers ap-
pearing 6–7 d after inoculation were counted. Three repeti-
tions were conducted for each compound [30]. The inhibi-
tion rate of the compound was calculated according to the
following formula (av denotes average).
8
10
a) Reaction conditions: A mixture of 1 equiv of (R,R)-1,2-diamino-
cyclohexane 1 in dry DCM was placed under an atmosphere of argon and
cooled to 0 °C. Then, a solution of intermediates 2a (1 equiv) in dry DCM
was added drop wise via syringe over different periods of time, as indi-
cated. The resulting yellow solution was left to stir overnight. b) Isolated
yield after purification via column chromatography on silica gel.
Table 2 Effect of temperature on the synthesis of 3a from diamine 1 and
isothiocynate 2a a)
av local lesion no. of right leave
not treated with compound


inhibition rate % 


av local lesion no. of right leave
not treated with compound


av local lesion no. of left leave
smearedwithcompound
Entry
Reaction temperature x (°C)
Yield b) (%)



100%
1
2
3
4
20
0
38
56
40
32
av local lesion no. of right leave
not treated with compound


10
20
3 Results and discussion
a) Reaction conditions: A mixture of 1 equiv of (R,R)-1,2-diamino-
cyclohexane 1 in dry DCM was placed under an atmosphere of argon at
x °C. Then, a solution of intermediate 2a (1 equiv) in dry DCM was added
drowse via syringe over 4 h. The resulting yellow solution was left to stir
overnight. b) Isolated yield after purification via column chromatography
on silica gel.
3.1 Synthesis
To optimize the conditions for the preparation of intermedi-
ate 3a, the reaction was first carried out at 0 °C by making

Yang X, et al. Sci China Chem January (2011) Vol.54 No.1
107
Table 4 The curative effect of the new compounds against TMV and
CMV in vivo a )
addition time beyond 4 h did not affect the overall yield of
the product significantly (Table 1, entries 4, 5, 6). Keeping
other parameters intact, the reaction temperature was then
varied from 20 °C to +20 °C (Table 2). The optimal yield
of 56% (Table 2, entry 2) was observed at 0 °C. Having
established the most suitable reaction conditions for inter-
mediate 3a in DCM, the role of different solvents e.g. THF,
DCM, acetonitrile, DMF and toluene was then studied for
the synthesis of title chiral compound 10a from the reaction
of intermediate 3a with intermediate 9a. As can be seen
from the data presented in Table 3, under optimal conditions
when intermediate 3a was reacted with 1 molar equiv of
intermediate 9a in THF at room temperature for 0.5 h, the
target chiral compound 10a was obtained in 85% yield (Ta-
ble 3, entry 1).
Concentration
(mg/mL)
Curative effect
against CMV (%)
Curative effect
against TMV (%)
Agents
10a
10b
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
60.3**
37.1*
29.9*
37.0*
64.8**
41.9*
49.0**
32.7*
47.0*
31.0*
37.9*
31.1*
58.7**
50.3*
31.2*
39.3*
35.2*
50.8**
44.1*
22.1*
28.9*
39.4*
10.2
10c
10d
10e
10f
10g
10h
10i
10j
10k
29.3*
33.2*
56.3**
10l
3.2 Antiviral activity and structure-activity relationship
Ningnamycin
To make a judgment of the antiviral potency of the synthe-
sized chiral compounds 10a–l, the commercially available
plant virucide Ningnanmycin, perhaps the most successful
registered anti-plant viral agent available in China, was used
as the control. The bioassay against CMV and TMV is as-
sayed by the reported method [27–30], and antiviral results
of all the compounds against CMV and TMV are listed in
Table 4. The results showed that some of our designed
compounds had moderate to good antiviral activities at 0.5
mg/mL against CMV and TMV in vivo.
a) n = 3 for all groups; * P < 0.05, **P < 0.01.
activities ranging from 29.9%–64.8% against CMV at
0.5 mg/mL. Amongst them, 10e [R1 = (R)-1-phenylethyl,
R2=Et], 10a [R1 =Ph, R2 =Et] and 10g [R1 = (R)-1-phenylethyl,
R2 = i-Pr] showed much higher curative activities (64.8%,
60.3% and 49.7%, respectively) which were comparable to
that of the standard reference (58.7%). As for curative bio-
activities against TMV, it is evident from Table 4 that
compounds 10a, 10e and 10f [R1 = (S)-1-phenylethyl, R2 =
Et] afforded the best results withinhibitory rates of 50.3%,
50.8% and 44.1%, respectively. In fact, 10a and 10e proved
almost as effective as the commercial product Ningnanmycin
(56.3%). The nature of substituents present in the title com-
pounds seems to affect the overall result to a great extent.
Comparison of the values as displayed by 10a–l, clearly re-
veals that the title compounds derived from diethyl
phosphite (R2 = Et) were far more active than those derived
from other dialkyl phosphites (R2 = n-Pr, i-Pr and n-Bu.
Again, as expected of these synthesized chiral compounds,
bioactivity is dependent on the nature of absolute configura-
tions and hence on the type of isothiocyanates 2 involved in
their preparation. The chiral thioureas 10e, 10g, 10i and 10k
derived from (R)-enantiomer [R1 = (R)-1-phenylethyl] dis-
played superior activity against CMV (inhibitory rate =
64.8%, 49.0%, 47.0% and 37.9% respectively) than 10f,
10h, 10j and 10l (inhibitory rate = 41.9%, 32.7%, 31.0% and
31.1% respectively) which were prepared from (S)-enantiomer
[R1 = (S)-1-phenylethyl] of isothiocyanate 2. Similarly, the
thioureas 10e, 10g, 10i and 10k derived from (R)-enantiomers
[R1 = (R)-1-phenylethyl] were more active against CMV
(inhibitory rate = 64.8%, 49.0%, 47.0% and 37.9% respec-
tively) compared to their respective (S) enantiomers 10f,
10h, 10j and 10l (inhibitory rate = 41.9%, 32.7%, 31.0% and
31.1% respectively).
All the synthesized compounds 10a–l exhibited curative
Table 3 Compatibility of different solvents for the synthesis of 10a a)
Entry
Solvent
THF
Yield b) (%)
1
2
3
4
5
85
80
78
72
75
DCM
CH3CN
DMF
Toluene
a) Reaction conditions: The reaction was conducted with 1 equiv of in-
termediate 3a and 1 equiv of intermediate 9a in various solvents at room
temperature. The solution was stirred for 0.5 h. b)Isolated yield after puri-
fication via column chromatography on silica gel.
Selected compounds 10a, 10e, 10f and 10g displaying

108
Yang X, et al. Sci China Chem January (2011) Vol.54 No.1
remarkable curative effects against TMV and CMV (Table
4) were identified for further antiviral-bioassay and the re-
sults were compared with commercial plant antiviral agent
Ningnanmycin as shown in Table 5. The compound 10a
which was not derived from chiral isothiocyanate (R1 = Ph)
and compounds 10f [R1 = (S)-1-phenylethyl] and 10g [R1 =
(R)-1-phenylethyl] were fairly effective in curating TMV.
Their EC50 values were recorded as 0.320, 0.525 and 0.378
mg/mL, respectively. It should also be noted that the cura-
tive effects of 10a, 10e and 10g against CMV were signifi-
cant, being 0.187, 0.149 and 0.359 mg/mL, respectively.
Amongst all the studied compounds, the thiourea 10e pre-
pared from diethyl phosphite and chiral isothiocyanate 2b
[R1 = (R)-1-phenylethyl] displayed more potent antiviral
activity comparable to Ningnanmycin (0.201 mg/mL) against
CMV. It must be noted that the synthesized compounds
were stable under ordinary conditions of use and storage
and were generally not affected by the trace amount of
moisture or light.
appropriate selection of dialkyl phosphites and suitable con-
trol on the substituents and absolute configuration (R or S)
of isothiocyanate 2. It was found that the chiral thioureas
10e, 10g, 10i and 10k derived from (R)-enantiomer of
isothiocyanate displayed better anti-CMV activities than
compounds 10f, 10h, 10j and 10l [R1 = (S)-1-phenylethyl]
which were derived from (S)-enantiomer of isothiocyanate.
In addition, the compound 10e showed more potent antiviral
activity (EC50 = 0.149 mg/mL) than Ningnanmycin (EC50 =
0.201 mg/mL) against CMV. Influence of subtle structural
modification and steric parameters on structure activity re-
lationships for identifying lead bioactive compound would
be taken up in our future course of investigation.
4
Supporting information available
The synthetic and analytical data for 3a–c, 4, 5, 6a–d, 7a–c,
8a–d, 9a–d, 10a–l. This information is available free of
charge via the internet at http://www. springerlink. com/
content/121600/
In summary, a series of novel chiral bis-thiourea-type de-
rivatives containing an -aminophosphonate moiety was
synthesized from 1-((1R,2R)-2-aminocyclohexyl)-3-substituted
thiourea (3a–c) and substituted isothiocyanate (9a–d) de-
rived from dialkyl phosphites. The reaction conditions for
the multi-step synthesis were carefully optimized to prepare
the title compounds. The in vivo tests indicated that the bis-
thioureas 10a and 10e, both derived from diethyl phosphite,
possessed good curative bioactivities (inhibitory rate =
60.3%, 64.8% respectively) on CMV, comparable to that of
the standard reference (58.7%). They also displayed similar
curative bioactivities on TMV (inhibitory rate = 50.3%,
50.8% respectively) as the commercial product Ningnan-
mycin (56.3%). The nature of dialkyl phosphites and chiral
isothiocyanates 2 involved in the preparation of title com-
pound is absolutely vital in the design of new compounds
with desired activity. Thus, the antiviral activity of chiral
bis-thiourea derivatives was significantly improved by
The authors wish to thank the National Key Project for Basic Research
(2010CB 126105), and the National Natural Science Foundation of China
(20872021) for the financial support.
1
Song BA, Yang S, Jin LH, Bhadury PS. Environment-friendly Anti-
viral Agents for Plants. Springer press. 2009, 1–10
2
3
Schroeder DC. Thioureas. Chem Rev, 1955, 55: 181–228
Chalina EG, Chakarova L. Synthesis, hypotensive and antiarrhythmic
activities of 3-alkyl-1-(2-hydroxy-5,8-dimethoxy-1,2,3,4-tetrahydro-
3-naphthalenyl)ureas or thioureas and their guanidine analogues. Eur
J Med Chem, 1998, 33: 975–983
4
5
Stark H, Purand K, Ligneau X, Rouleau A, Arrang JM, Garbarg M,
Schwartz JC, Schunack W. Novel carbamates as potent histamine H3
receptor antagonists with high in vitro and oral in vivo activity. J Med
Chem, 1996, 39: 1157–1163
Walpole C, Ko SY, BrownM, BeattieD, Campbell E, Dickenson F,
Ewan S, Hughes GA, Lemaire M, Lerpiniere J, Patel S, Urban L.
2-Nitrophenylcarbamoyl-(S)-prolyl-(S)-3-(2-naphthyl)alanyl-N-benzy
l-N-methylamide (SDZ NKT 343), a potent human NK1 tachykinin
receptor antagonist with good oral analgesic activity in chronic pain
models. J Med Chem, 1998, 41: 3159–3173
Table 5 Antiviral activities in vivo (%) of chiral compounds 10a, 10e,
10f and 10g
6
7
Schreiner PR, Wittkopp A. H-bonding additives act like Lewis acid
catalysts. Org Lett, 2002, 4: 217–220
Wittkopp A, Schreiner PR. Metal-free, noncovalent catalysis of Diels-
Alder reactions by neutral hydrogen bond donors in organic solvents
and in water. Chem Eur J, 2003, 9: 407–414
Virus
Concentration (mg/mL)
10a a)
Curative effect
0.250 0.125 EC50 (mg/mL)
0.500
50.4
50.8
44.1
50.4
60.3
64.8
49.0
56.2
58.2
8
9
Connon SJ, Organocatalysis mediated by (thio)urea derivatives.
Chem Eur J, 2006, 12: 5418–5427
Zhang Z, Schreiner PR. Organocatalytic biomimetic reduction of
conjugated nitroalkenes. Synthesis, 2007, 16: 2559–2564
39.4
48.1
30.1
37.2
57.6
59.8
33.2
51.0
52.1
35.1
40.9
20.0
32.9
48.0
51.0
22.1
44.1
47.9
0.320
0.220
0.525
0.378
0.187
0.149
0.359
0.212
0.201
10e a)
10f a)
10g a)
10a b)
10e b)
10g b)
10 Venkatachalam TK, Sudbeck EA, Mao C, Uckun FM. Stereochemis-
try of halopyridyl and thiazolyl thiourea compounds is a major de-
terminant of their potency as nonnucleoside inhibitors of HIV-1 re-
verse transcriptase. Bioorg Med Chem Lett, 2000, 10: 2071–2074
11 Venkatachalam TK, Sudbeck EA, Mao C, Uckun FM. Anti-HIV ac-
tivity of aromatic and heterocyclic thiazolyl thiourea compounds.
Bioorg Med Chem Lett, 2001, 11: 523–528
12 Venkatachalam TK, Mao C, Uckun FM. Stereochemistry as a major
determinant of the anti-HIV activity of chiral naphthyl thiourea
compounds. Antiviral Chem & Chemother, 2001, 12: 213–221
Ningnamycin a)
Ningnamycin b)
a) EC50 values on TMV; b) EC50 values on CMV.

Yang X, et al. Sci China Chem January (2011) Vol.54 No.1
109
13 Venkatachalam TK, Mao C, Uckun FA. Effect of stereo and regio-
chemistry towards wild and multidrug resistant HIV-1 virus: Viral
potency of chiral PETT derivatives. Biochem Pharmaco, 2004, 67:
1933–1946
14 Venkatachalam TK, Mao C, Uckun FM. Effect of stereochemistry on
the anti-HIV activity of chiral thiourea compounds. Bioorg Med
Chem, 2004, 12: 4275–4284
of -aminophosphonate by a one-pot three-component condensation
of carbonyl compound, amine and diethyl phosphite without solvent
and catalyst. Green Chem, 2002, 4: 551–554
23 Chen MH, Chen Z, Song BA, Bhadury PS, Yang S, Cai XJ, Hu DY,
Xue W, Zheng S. Synthesis and antiviral activities of chiral thiourea
derivatives containing an -aminophosphonate moiety. J Agric Food
Chem, 2009, 57: 1383–1388
15 Kafarski P; Lejczak B. Biological activity of aminophosphonic acids.
Phosphorus Sulfur 1991, 63, 193–215
16 Song BA, Wu YL, Yang S, Hu DY, He XQ, Jin LH, Lu P. Synthesis
and bioactivity of -aminophosphonates containing fluorine. Mole-
cules, 2003, 8: 186–192
17 Yang S, Gao XW, Diao CL, Song BA, Jin LH, Xu GF, Zhang GP,
Wang W, Hu DY, Xue W, Zhou X, Lu P. Synthesis and antifungal
activity of novel chiral R-aminophosphonates containing fluorine
moiety. Chin J Chem, 2006, 24: 1581–1588
18 Sasai H, Arai S, Tahara, Y. Catalytic asymmetric synthesis of
-amino phosphonates using Lanthanoid-Potassium-BINOL com-
plexes. J Org Chem, 1995, 60: 6656–6657
19 Firouzabadi H, Iranpoor N, Sobhan SI. Metal triflate-catalyzed
one-pot synthesis of a-aminophosphonates from carbonyl compounds
in the absence of solvent. Synthesis, 2004, 16: 2692
20 Manjula A, Vittal BR, Neelakantan P. One-pot synthesis of
-aminophosphonates: An inexpensive approach. Synth Commun,
2003, 33: 2963–2969
21 Kaboudin B. A convenient synthesis of 1-aminophosphonates from
1-hydroxyphosphonates. Tetrahedron Lett, 2003, 44: 1051–1053
22 Ranu BC, Hajra RA. A simple and green procedure for the synthesis
24 Procuranti B, Connon SJA. Reductase-mimicking thiourea organo-
catalyst incorporating a covalently bound NADH analogue: Efficient
1,2-diketone reduction with in situ prosthetic group generation and
recycling. Chem Commun, 2007, 14: 1421–1423
25 Kaboudin B, Moradi K. A simple and convenient procedure for the
synthesis of 1-aminophosphonates from aromatic aldehydes. Tetra-
hedron Lett. 2005, 46: 2989–2991
26 Wang T, Ye WF, He HW. Preparation of isocyanates, isothiocyanates
and isoselenocyanates in the laboratory. Chem Reagent, 2002, 24(4):
204–207
27 Gooding GV Jr, Hebert TT, A simple technique for purification of
tobacco mosaic virus in large quantities. Phytopathology. 1967, 57:
1285–1290
28 Song BA, Zhang HP, Wang H, Yang S, Jin LH, Hu DY, Pang LL,
Xue W. Synthesis and antiviral activity of novel chiral cyanoacrylate
derivatives. J Agric Food Chem, 2005, 53: 7886–7891
29 Sheng JG, Xie LY, Zhang ZK, Xie LH, Lin QY. Effect of extracts
from Pt on CMV, PVYN and insect vector. Chinese Agric Sci Bull,
2005, 21: 341–344
30 Zhou XP, Xu ZX, Xu J, Li DB. Studies on cucumber mosaic virus iso-
lated from Luffa cylindrica. J South China. Agric Univ, 1995, 16: 74–79