Synthesis and biological evaluation of novel 5-alkyl-2-arylthio-6-((3,4- dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-ones as potent non-nucleoside HIV-1 reverse transcriptase inhibitors

Article abstract of DOI:10.1016/j.bmc.2011.05.024

A series of novel S-DABO analogues of 5-alkyl-2-arylthio-6-((3,4- dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-ones were synthesized and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). Among them, the most potent HIV-1 inhibitor

Full text of DOI:10.1016/j.bmc.2011.05.024

Bioorganic & Medicinal Chemistry 19 (2011) 4366–4376
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis and biological evaluation of novel 5-alkyl-2-arylthio-6-((3,4-dihydro-
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-ones as potent non-nucleoside
HIV-1 reverse transcriptase inhibitors
Jing Zhang a, Peng Zhan a, Jingde Wu a, Zhenyu Li a, Yan Jiang a, Weiying Ge a, Christophe Pannecouque b,
Erik De Clercq b, Xinyong Liu a,
⇑
a Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, Jinan, Shandong 250012, PR China
b Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel S-DABO analogues of 5-alkyl-2-arylthio-6-((3,4-dihydroquinolin-1(2H)-yl)methyl)pyr-
imidin-4(3H)-ones were synthesized and evaluated as inhibitors of human immunodeficiency virus
type-1 (HIV-1). Among them, the most potent HIV-1 inhibitors were compounds 6c1, 6c6, and 6b1
Received 15 February 2011
Revised 16 May 2011
Accepted 16 May 2011
Available online 23 May 2011
(EC50 = 0.24 0.05, 0.38 0.13, 0.39 0.05
inhibitory activity compared with nevirapine (NVP) (EC50 = 0.21
0.32 M). None of these compounds were active against HIV-2 replication. Furthermore, enzyme inhib-
lM, respectively), which possess improved or similar HIV-1
l
M) and delavirdine (DLV) (EC50
=
l
Keywords:
HIV-1
AIDS
NNRTIs
S-DABOs
Anti-HIV-1 activity
itory assays were performed with selected derivatives against HIV-1 wtRT, confirming that the main tar-
get of these compounds is the HIV-1 RT and these new S-DABOs are acting as NNRTIs. The preliminary
structure–activity relationship (SAR) of these new congeners is discussed briefly and rationalized by
docking studies.
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
of S-DABOs at the C-2 position of the pyrimidine ring exert their
favorable effect on anti-HIV-1 activity by the interaction with the
Since dihydro-alkoxy-benzyl-oxopyrimidines (DABOs) were
disclosed as potent HIV-1 non-nucleoside reverse transcriptase
inhibitors (NNRTIs) in 1992, much effort have been paid for the
structural modifications with a view to increase potency and
decrease drug resistance. Up to now, three types of DABO
analogues have been studied based on the C-2 substitutent
features, that is, dihydroalkyloxybenzyloxopyrimidines (O-DABOs),
dihydroalkylthio benzyloxopyrimidines (S-DABOs) and dihy-
droalkylaminodifluorobenzyloxopyrimidines (N-DABOs) (Fig. 1).1
Among DABO derivertives, S-DABOs were the most potent and
selective HIV-1 NNRTIs, with the C-2 alkylthio chain being the pe-
culiar determinant for exhibition of anti-HIV-1 activity. The
HNC@O fragment at N3/C4 position of the pyrimidine is a crucial
factor for keeping the activity, because the hydrogen bonds are
formed by N3-H with the carbonyl group of Lys101 inside the
hydrophobic pocket of RT.2–4 The optimal moieties at positions 5
of the pyrimidine nucleus were dependent on the nature of the
C-2 side chain. Both arylcarbonylmethyl and benzyl substituent
side chain Pro236 of RT binding site.5,6 Chemical modifications of
C-6 substituents led to find numerous compounds as potent
HIV-1 NNRTIs by replacement of benzyl moieties with substituted
benzyl, 1-naphthylmethyl and 2-naphthylmethyl groups, whereas
the introduction of alkyl, phenyl or phenylethyl, phenoxymethyl,
and phenylthiomethyl groups to C-6 position resulted in com-
pounds with no or decreased antiviral activity.7,8
According to a recent success in the modification of S-DABOs
with 1-naphthylmethyl at C-6 position (DATNOs) by He et al.
(Fig. 1),7,8 together with the previous SARs studies of DABOs, a no-
vel series of 6-((3,4-dihydroquinolin-1(2H)-yl)methyl) substituted
S-DABOs were designed and synthesized based on the general
principle of bioisosterism in medicinal chemistry. We postulated
that the newly constructed S-DABOs, retaining C-2 preferential ac-
tive groups and intrducing novel C-6 side chain, might be more
favorable to improve a putative
p-stacking interaction between
the aryl ring of the ligand and Tyr188 or Tyr181 of RT, and further
exploration of the structure–activity relationships of S-DABOs may
yield the discovery of new more potent HIV-1 inhibitors. Here, the
synthesis and the anti-HIV evaluation of the designed S-DABOs in
MT-4 cell culture are reported.
⇑
Corresponding author. Tel.: +86 531 88380270; fax: +86 531 88382731.
E-mail address: xinyongl@sdu.edu.cn (X. Liu).
0968-0896/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2011.05.024

J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
4367
O
O
N
O
N
R
R
R
X
HN
HN
HN
R2
R2
R2
S
N
O
S
R1
R1
DABOs
S-DABOs
R =H, Me, Et, i-Pr
DATNOs
R =H, Me, Et, i-Pr
R2 =alkyl, cycloalkyl, ArCOCH2
R =H, Me, Et
R1=H, 3-Me, 2,6-Cl2-Ph, 2,6-F2-Ph
R2 =alkyl, cycloalkyl, ArCOCH2
X =CH2,S, CHCN, C=O
R1=H, 3-Me, 3,5-Me2
R2=alkyl, cycloalkyl
O
O
R
R1
HN
HN
R2
R1
R2
N
R3
N
F
S
N
F
N
N-DABOs
Newly designed S-DABOs
R =R1=H, Me
R2=H, alkyl, cycloalkyl
R3=alkyl, cycloalkyl
Figure 1. The DABOs families and the newly designed S-DABOs.
2.2. Biological activity
2. Results and discussion
2.1. Chemistry
All of the newly designed and synthesized S-DABO analogues
(compounds 6a1–14, 6b1–14, 6c1–14) were evaluated for cytotox-
icity and anti-HIV activity in MT-4 cells infected with wild-type
HIV-1 strain IIIB and HIV-2 strain ROD. The results, expressed as
EC50, CC50 and SI (selectivity index), are illustrated in Table 1 to-
gether with those of nevirapine (NVP), delaviridine (DLV), efavi-
renz (EFV) and zidovudine (azidothymidine, AZT), which were
used as reference drugs.13–15
The synthetic route of the newly designed compounds is
described in Scheme 1. The key intermediate b-ketoesters 4 were
prepared with a simple method reported by Clay et al.9 through
the reaction of 3 with N,N0-carbonyldiimidazole (CDI) followed by
treatment with different ethyl potassium malonates in the pres-
ence of anhydrous MgCl2 and Et3N.10,11 Next, the cyclization reac-
tion of b-ketoesters 4 with thiourea in the presence of EtONa in
refluxing EtOH gave the substituted uracil 5.12 Treatment of 5 with
appropriate arylcarbonylmethyl halides or benzyl halides in the
presence of K2CO3 in anhydrous DMF afforded the desirable target
compounds 6a1–14, 6b1–14, 6c1–14. Both analytical and spectral
data of all the compounds are in full agreement with the proposed
structures.
Of the newly synthesized S-DABO analogues, compounds 6c1
(EC50 = 0.24
6b6 (EC50 = 0.42
which inhibited HIV-1 replication in cell culture. It should be
noted that compound 6c1 (EC50 = 0.24 M) possesses similar
HIV-1 inhibitory activity as NVP (EC50 = 0.21 M) and DLV
M). Comparing the different substitutions at
lM), 6c6 (EC50 = 0.38
lM), 6b1 (EC50 = 0.39 lM) and
lM) were found to be the active compounds
l
l
(EC50 = 0.32
l
O
O
O
O
OH
OEt
O
H
N
N
R1
N
N
i
iii
ii
4a: R1=H
4b: R1=CH3
4c: R1=CH2CH3
1
3
2
O
N
O
N
R1
N
R1
N
HN
HN
iv
v
S
R2
HS
5a, 5b, 5c
6a1 - 6a14
6b1 - 6b14
6c1 - 6c14
Scheme 1. Reagents and conditions: (i)K2CO3, ethyl 2-bromoacetate, toluene, 24 h, 90 °C; (ii) 15% NaOH, 15 h; (iii) (a) CDI, CH3CN, rt, 30 min; (b) MgCl2, Et3N,
R1CH(CO2Et)(CO2K), rt, overnight then reflux, 2 h; (iv) thiourea, EtONa, reflux, 6–12 h; (v) arylcarbonylmethyl halides or benzyl halides, K2CO3, DMF, rt, 12 h.

4368
J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
Table 1
Anti-HIV-1 activities, cytotoxicities and selectivity indices of new designed S-DABO derivatives (6a1–c14)
O
R1
HN
S
N
R2
N
a
b
Compound Nos.
R1
R2
EC50
(
lM)
CC50
(lM)
SI (IIIB)c
HIV-1 (III B)
HIV-2 (ROD)
6a1
6a2
6a3
6a4
6a5
6a6
6a7
6a8
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Et
Et
Et
Et
Et
Et
Et
Et
Et
PhCOCH2
24.60 7.48
27.99 0.17
>75.60
>208.78
>196.88
24.03 0.29
29.55 0.17
P32.19
>64.32
>53.60
>152.57
>156.05
>75.60
>208.78
>196.88
>159.55
>135.90
>94.17
>64.32
>53.60
>73.89
>86.82
>180.94
>182.32
>12.18
>62.35
>42.10
>23.70
>44.45
>60.70
>15.43
>6.69
>86.20
>65.55
>76.88
>12.98
>59.55
>8.67
>297.95
>288.3
>275.34
>110.99
>114.86
>61.84
>156.06
>4.80
152.57 14.07
156.05 0.95
75.60 46.23
208.78 44.42
>196.88
159.55 0.29
135.90 17.12
94.17 46.74
64.32 16.61
>53.60
73.89 36.38
86.82 30.35
180.94 42.19
182.32 67.66
12.18 0.93
62.35 23.56
42.10 34.13
23.70 5.14
44.45 7.96
60.70 7.54
15.43 5.93
6.69 4.99
P86.20
65.55 16.78
76.88 9.91
12.98 1.96
59.55 9.52
8.67 4.43
297.95
6
6
<1
<1
< or >1
7
5
63
<1
<1
62
62
7
6
31
32
19
68
6
144
34
(40-CH3)PhCOCH2
(40-Cl)PhCOCH2
(40-NO2)PhCOCH2
(40-CN)PhCOCH2
(40-OCH3)PhCOCH2
(40-F)PhCOCH2
PhCH2
6a9
(40-CH3)PhCH2
(40-Cl)PhCH2
(40-NO2)PhCH2
(40-CN)PhCH2
(40-OCH3)PhCH2
(40-F)PhCH2
6a10
6a11
6a12
6a13
6a14
6b1
6b2
6b3
6b4
6b5
6b6
6b7
6b8
6b9
6b10
6b11
6b12
6b13
6b14
6c1
6c2
6c3
6c4
6c5
6c6
6c7
6c8
6c9
6c10
6c11
6c12
6c13
6c14
NVPd
DLVd
EFVd
AZTd
P49.45
P42.99
25.13 3.28
29.65 6.63
0.39 0.05
1.95 0.07
2.16 0.08
P3.13
7.35 6.01
0.42 0.08
0.46 0.03
>6.69
PhCOCH2
(40-CH3)PhCOCH2
(40-Cl)PhCOCH2
(40-NO2)PhCOCH2
(40-CN)PhCOCH2
(40-OCH3)PhCOCH2
(40-F)PhCOCH2
PhCH2
<1
(40-CH3)PhCH2
(40-Cl)PhCH2
(40-NO2)PhCH2
(40-CN)PhCH2
(40-OCH3)PhCH2
(40-F)PhCH2
P86.20
P2.25
<or ꢀ1
629
41
7
93
1.88 0.04
1.78 0.18
0.64 0.04
>8.67
0.24 0.05
1.06 0.67
1.01 0.07
1.98 0.92
1.06 0.09
0.38 0.13
0.57 0.053
>4.80
P5.42
P5.42
1.03 0.25
0.48 0.34
0.59 0.24
>133.16
<1
PhCOCH2
1218
271
249
56
109
164
273
<1
(40-CH3)PhCOCH2
(40-Cl)PhCOCH2
(40-NO2)PhCOCH2
(40-CN)PhCOCH2
(40-OCH3)PhCOCH2
(40-F)PhCOCH2
PhCH2
288.3
275.34
110.99 35.69
114.86 67.96
61.84 23.31
156.06 23.18
4.80 0.43
159.6 59.4
135.22
194.71 21.99
59.68 44.49
147.26 26.82
133.16
(40-CH3)PhCH2
(40-Cl)PhCH2
(40-NO2)PhCH2
(40-CN)PhCH2
(40-OCH3)PhCH2
(40-F)PhCH2
>159.6
>135.22
>194.71
>59.68
>147.26
>133.16
29
Et
Et
Et
Et
625
188
125
244
<1
>72
>12
>1434
>6192
Et
0.21
0.32
0.0044
0.015
>15.02
>3.83
>6.34
>93.55
a
b
c
EC50: concentration of compound required to achieve 50% protection of MT-4 cells against HIV-induced cytotoxicity, as determined by the MTT method.
CC50: concentration required to reduce the viability of mock-infected cells by 50%, as determined by the MTT method.
SI: selectivity index (CC50/EC50).
d
The antiviral properties of these compounds were previously described.
C-5 position, the activity of series C5-Et (6c1–14) was obviously
better than C5-Me series (6b1–14), and, followed by C5-H series
(6a1–14) (Table 1), confirmed that the steric bulkiness of C-5 sub-
stituent is favored to maintain inhibitory activity against HIV-1
replication. It is noteworthy that the introduction of a methyl
group (series 6b) maintained the biological activity, but led to in-
creased cytotoxicity, thus providing important information for fur-
ther design of novel analogues.
Just as SAR of S-DABOs made in previous studies, the nature of
the substituents at the para substitution at the phenyl ring of the
C-2 moiety essentially influences the anti-HIV-1 activity. As shown
in Table 1, introduction of substituted arylcarbonylmethyl groups
at the C-2 side chain led to compounds 6c1–7 with much better
activity and selectivity index than the corresponding benzyl substi-
tuted compounds 6c8–14. In addition, when the nitro, cyano and
methoxyl group are introduced to the para-position of the benzyl

J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
4369
moiety, the bioactivity and selectivity index of these compounds
(6c11–13) were slightly increased. The experimental results indi-
cated that the majority of the tested series 6b (6b1-14) were found
30.68
l
M, with NVP 4.4
l
M being the reference, which further
indicated that the main target of these compounds is exactly at
the HIV-1 RT. However, the IC50 value of compound is slightly
inconsistent with the result of cell test, which probably because
that these new compounds might interfere with another target
or act on reverse transcriptase in a different way other than the
typical NNRTIs binding pocket. In addition, all of the title com-
pounds were evaluated for their capability to inhibit the HIV-2
(strain ROD) replication in MT-4 cells but no one was active against
HIV-2 (ROD). Based on the chemical structure and the general
characters that NNRTIs inhibit HIV-1 but not HIV-2 replication, it
could be concluded that the new series of S-DABOs were specific
for HIV-1 and still belonged to HIV-1 NNRTIs.
to be active against HIV-1 in the range of 0.39–7.7 lM and agreed
with previous SARs findings in 6c series (6c1–14). Thus, low selec-
tivity index of 6b series may partly due to their high cytotoxicity.
Compared to the previous S-DABOs with 1-naphthylmethyl at
C-6 position, the new compounds showed modest antiviral
activity.8 Based on these results and the fact that charge-transfer
interactions between the p-stacking aromatic rings at C-6 position
of S-DABOs and Tyr188 and Tyr181 in HIV-1 RT probably play an
important role in keeping anti-HIV activity, it is suggested that
the nature of the 3,4-dihydroquinolin-1(2H)-yl)methyl group did
not accommodate the chemical environment well in this region
of RT. The full description on this issue will be discussed in the
following section of molecular simulation analysis.
2.4. Molecular simulation
To investigate the structure–activity relationships of our newly
synthesized compounds, 6c1 was docked into the NNRTIs binding
pocket (NNIBP) of HIV-1 RT by means of Autodock Vina [http://vi-
na.scripps.edu]. X-ray crystal structure of HIV-1 RT with 6-benzyl-
1-(benzyloxymethyl)-5-isopropylpyrimidine-2,4(1H,3H)-dione
(TNK-651) was taken from PDB (1rt1) and used for docking studies
for the high degree of similarity between TNK-651 and S-DA-
BOs.4,16,17 Default parameters were used as described in the Auto-
dock Vina manual unless otherwise specified. The theoretical
binding mode of 6c1 to the NNIBP is shown in Figure 2(a).
2.3. Enzyme inhibiting activity against HIV-1 wild-type RT
In order to prove that the newly synthesized compounds were
targeted at the HIV-1 RT directly, we chose one compound (6c1)
to evaluate for HIV-1 RT inhibitory activity, using a poly(rA)/oli-
go(dT)15 homopoly-mer template with the HIV antigen detection
ELISA for quantifying expression of HIV-1 RT in culture medium,
and nevirapine as a reference compound. The results showed that
this new compound inhibited the HIV-1 RT with an IC50 value
Figure 2. (a) Model of 6c1 docked into the RT non-nucleoside binding site (PDB code: 1rt1) using Autodock Vina [http://vina.scripps.edu]. (b) For comparison purposes, the
docked conformation of 6c7 (EC50 = 0.57 0.053 M) and 4j (red), an earlier 1-naphthylmethyl-S-DABO (EC50 = 0.078 0.009 M), are shown in stick representation. The
docking result of above is showed by PyMOL [http://pymol.sourceforge.net].
l
l

4370
J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
The docking simulation showed the binding mode of the 6c1
(80 mL), ethyl 2-bromoacetate (5.0 g, 29.94 mmol) was added. The
reaction mixture was stirred at 90 °C for 24 h (monitored by TLC).
Upon completion of the reaction, the reaction mixture was cooled
to room temperature, filtered off K2CO3 and concentrated in vacuo
and the residue was extracted with chloroform (3 ꢀ 50 mL). The
organic layer was washed with brine, dried over Mg2SO4 and evap-
orated to give a crude compound, which was purified over silica gel
column by eluting with ethyl acetate/petroleum ether (1:4) to ob-
tain a brown colored liquid.18
into the NNIBP (Fig. 2a). Results showed that the NHC@O fragment
at N3/C4 positions of pyrimidine ring was stabilized by a hydrogen
bond between the N3-H function of S-DABOs and the carbonyl oxy-
gen of Lys101. The extended side chain at C-2 position point to-
ward into a pocket mainly formed by Val106, Pro225, Pro236,
and Phe227, with the length and size of the C-2 side chain having
only modulator effects on potency. A hydrogen bond is formed be-
tween the C@O group of the C-2 side chain and NH group of Lys103
backbone. The ethyl group at C-5 position was positioned in the
hydrophobic cavity formed by the Val179 side chain.15 Moreover,
the 3,4-dihydroquinolin-1(2H)-yl)methyl substituent at position
6 of the pyrimidinone ring is located in a hydrophobic region
defined by Tyr181, Tyr188, Phe227, Trp229 and Leu234. As an
additional proof of the effect of the introduced feature, docking
experiments were also carried out on the reported 1-naphthyl-
4.1.2. General procedure for the preparation of b-ketoesters (4a,
4b, and 4c)
To a well stirred solution of substituted diethyl malonate
(500 mmol) in anhydrous EtOH (345 mL) was added dropwise a
solution of KOH (28 g, 500 mmol) in EtOH (345 mL) at room tem-
perature over 4 h. The resulting mixture was allowed to stand
overnight until the pH of the final mixture had a value between
7 and 8. After removing the solvent, the residue was rinsed with
ether and suspended in anhydrous acetonitrile (800 mL), then tri-
ethylamine (100 mL, 717 mmol) and magnesium chloride (57 g,
595 mmol) were added. The mixture was continued to stir at room
temperature for 2 h, then added a solution of arylacetyl imidazo-
lide which was previously prepared 15 min before by a reaction
of 2-[3,4-dihydroquinolin-1(2H)-yl]acetic acid (250 mmol) with
N,N0-carbonyldiimidazole (275 mmol) in acetonitrile (300 mL).
The reaction mixture was stirred overnight at room temperature
and then refluxed for 2 h.15 After cooling, the reaction mixture
was added a solution of 13% HCl (800 mL) and kept stirring for a
further 10 min. Finally, the organic layer was separated and con-
centrated; the residue was extracted with EtOAc (3 ꢀ 150 mL).
The combined organic layers were washed with saturated NaHCO3
(3 ꢀ 350 mL) and brine (3 ꢀ 350 mL), dried over anhydrous MgSO4,
filtered and concentrated to give the brown oily products 4a–4c,
which is used directly in the next step without further purification.
4a yield: 15.1%, MS (ESI): m/z 262.30 (M+1). 4b yield: 12.1%, MS
(ESI): m/z 276.41 (M+1). 4c yield: 10.7%, MS (ESI): m/z 290.33
(M+1).
methyl-S-DABO 4j (EC50 = 0.078 0.009 lM, red in Fig. 2b) in com-
parison with 6c7. The binding mode of 6c7 displayed a fair
superimposition to 1-naphthylmethyl-S-DABO 4j in NNIBP, show-
ing an overall common binding conformation. The superimposed
conformation clearly shows that the position of the tetrahydro-
quinoline ring is somehow slightly tilted in respect to the naphtha-
lene ring of 4j (Fig. 2b). Conformationnal change of C-6 may lead to
the lack of the
ligand and RT.
p-stacking interactions between the aryl ring of the
In summary, the results of the Auto Docking analysis seem to
support the SARs elucidation of our newly designed and synthe-
sized compounds. Further optimization of S-DABOs analogues will
take into account these aspects in further design attempts.
3. Conclusions
A
new series of 5-alkyl-2-arylthio-6-((3,4-dihydroquinolin-
1(2H)-yl)methyl)pyrimidin-4(3H)-ones (S-DABOs) were synthe-
sized and evaluated as potent HIV-1 inhibitors. Among them, the
most potent HIV-1 inhibitors were 6c1 (EC50 = 0.24
(EC50 = 0.38 M), 6b1 (EC50 = 0.39 M) and 6b6 (EC50 = 0.42
which possess similar HIV-1 inhibitory activity as NVP
(EC50 = 0.21 M) and DLV (EC50 = 0.32 M). The results of enzyme
l
M), 6c6
l
l
lM),
4.1.3. General procedure for the preparation of 5-alkyl-6-((3,4-
dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (5a, 5b
and 5c)
l
l
inhibitory assays also showed that these compounds were targeted
at the HIV-1 RT, thereby acting as NNRTIs. The preliminary struc-
ture–activity relationships and docking studies among the newly
disclosed congeners are discussed, which provided useful indica-
tions for guiding the further rational design of new S-DABO ana-
logues as more active and selective HIV-1 inhibitors.
Sodium methoxide was prepared by slow addition of a small
piece of sodium metal (6.9 g, 300 mmol), which was previously
pealed off and rinsed with the hexane, into 30 mL of anhydrous
methanol with vigorous stirring. When the sodium metal was
completely dissolved, thiourea (17.1 g, 225 mmol) and the corre-
sponding b-ketoesters 4a, 4b, 4c (150 mmol) were added to the
clear solution at room temperature. The reaction mixture was re-
fluxed for 10–12 h (monitored by TLC) under a nitrogen atmo-
sphere. After solvent was evaporated, the residue was dissolved
in H2O (80 mL) acidified by addition of 1 N HCl, and followed by
glacial AcOH to adjust to pH = 4. The produced precipitate was col-
lected, washed sequentially with H2O, EtOH, and Et2O and then
dried to give crude products 5a, 5b, and 5c, which were purified
by crystallization to afford the pure compounds.15 Compound 5a:
Recrystallized from EtOH/DMF as a brown crystal, yield: 67.1%,
mp: 238–240 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.41 (s, 1H,
N3H), 12.37 (s, 1H, N1H), 6.35–6.95 (m, 4H, quinoline-H), 5.41 (s,
1H, C5-H), 4.19 (s, 2H, NCH2) 3.31–3.33 (m, 2H, quinoline-H2),
2.71–2.73 (m, 2H, quinoline-H4), 1.89–1.90 (m, 2H, quinoline-H3).
ESI-MS: m/z 274.09 (M+1). C14H15N3OS (273.35). Compound 5b:
Recrystallized from EtOH/DMF as a brown crystal, yield: 70.3%,
mp: 227–228 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.01 (s, 1H,
N3H), 11.99 (s, 1H, N1H), 6.57–6.99 (m, 4H, quinoline-H), 5.41 (s,
1H, C5-H), 4.21 (s, 2H, NCH2) 3.15–3.17 (m, 2H, quinoline-H2),
2.68–2.70 (m, 2H, quinoline-H4), 1.86–1.88 (m, 2H, quinoline-H3),
4. Experimental
All the reactions were monitored by thin-layer chromatography
(TLC) on precoated silica gel G plates at 254 nm under a UV lamp.
Melting points were determined on a micromelting point appara-
tus and are uncorrected. Infrared spectra (IR) were recorded with
a Nexus 470 FT-IR Spectrometer. Mass spectrometer was taken
on Wasters Quattro Micro 2000. 1H-NMR spectra were recorded
on a Bruker Avance-600 using TMS as an internal standard and
chemical shifts are reported in d (ppm). Solvents were reagent
grade and, when necessary, were purified and dried by standard
methods.
4.1. Chemistry
4.1.1. General procedure for the preparation of ethyl-2-(3,4-
dihydroquinolin-1(2H)-yl) acetate (2)
To a stirred mixture of 1,2,3,4-tetrahydroquinoline (4.04 g,
30.37 mmol), anhydrous K2CO3 (8.4 g, 60.78 mmol) in dry toluene

J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
4371
1.79 (s, 3H, C5-CH3). ESI-MS: m/z 288.11 (M+1). C15H17N3OS
(287.38). Compound 5c: Recrystallized from EtOH/DMF as a brown
crystal, yield: 69.7%, mp: 210–211 °C (dec). 1H NMR (DMSO-d6,
ppm) d: 12.03 (s, 1H, N3H), 12.01 (s, 1H, N1H), 6.45–6.97 (m, 4H,
quinoline-H), 4.20 (s, 2H, NCH2) 3.30–3.37 (m, 2H, quinoline-H2),
2.37–2.45 (m, 2H, quinoline-H4), 2.28–2.31 (q, 2H, J = 7.2 Hz, C5-
CH2CH3), 1.68–1.79 (m, 2H, quinoline-H3), 1.79 (s, 3H, C5-CH3),
1.62–1.71 (m, 2H, quinoline-H3), 1.05 (t, 3H, J = 7.2 Hz, C5-CH2CH3).
ESI-MS: m/z 302.12 (M+1). C16H19N3OS (301.41).
J = 8.4 Hz, PhH), 6.35–6.95 (m, 4H, quinoline-H), 5.41 (s, 1H,
C5-H), 4.65 (s, 2H, SCH2), 4.19 (s, 2H, NCH2), 3.32–3.34 (m, 2H,
quinoline-H2), 2.71–2.73 (m, 2H, quinoline-H4), 1.89–1.90 (m, 2H,
quinoline-H3). IR (KBr, cmꢁ1
) m 3405 (NH), 2923, 2856 (CH2),
1703 (C@O), 1640 (C@O), 1579, 1508, 1458 (aryl), 1308 (C–N),
1185 (C–N). ESI-MS: m/z 437.51 (M+1). C22H20N4O4S (436.48).
4.1.4.5. 2-(4-Cyanophenylcarbonylmethylthio)-6-((3,4-dihydro-
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6a5).
Recrystallized from EtOH/DMF as a brown crystal,
4.1.4. General procedure for the preparation of target com-
pounds (6a1–14, 6b1–14, and 6c1–14)
yield: 43.3%, mp: 174–175 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.73 (s, 1H, NH), 7.67–7.98 (m, 4H, PhH), 6.73–7.01 (m, 4H, quin-
oline-H), 5.41(s, 1H, C5-H), 4.66 (s, 2H, SCH2), 4.12 (s, 2H, NCH2),
3.27–3.31 (m, 2H, quinoline-H2), 2.41–2.53 (m, 2H, quinoline-H4),
To a stirred solution of 5a, 5b, 5c (1.5 mmol) in anhydrous DMF
(10 mL) was added K2CO3 (0.23 g, 1.65 mmol) at room tempera-
ture. After stirring for 20 min, arylcarbonylmethyl halides or ben-
zyl halides (3.3 mmol) was added, and stirring was continued at
this temperature for other 10 h. The reaction mixture was poured
into cold H2O (100 mL), the resulting precipitate was collected by
filtration and washed sequentially with H2O, EtOH and Et2O, then
dried in vacuo at 40 °C to afford the corresponding crude product,
which was purified by crystallization or by flash chromatography
to give the pure target compounds 6a1–14, 6b1–14, and 6c–14.
1.79–1.90 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3391 (NH),
2925, 2848 (CH2), 2229 (C„N), 1662 (C@O), 1601 (C@O), 1581,
1504, 1458 (aryl), 1272 (C–N), 1198 (C–N). ESI-MS: m/z 417.52
(M+1). C23H20N4O2S (416.50).
4.1.4.6. 2-(4-Methoxylphenylcarbonylmethylthio)-6-((3,4-dihy-
droquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6a6).
Recrystallized from EtOH/DMF as a brown crystal,
yield: 39.1%, mp: 163–165 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.72 (s, 1H, NH), 8.02 (d, 2H, J = 8.4 Hz, PhH), 7.07(d, 2H,
J = 8.4 Hz, PhH), 6.28–6.87 (m, 4H, quinoline-H), 5.82 (s, 1H, C5-
H), 4.69 (s, 2H, SCH2), 4.03 (s, 2H, NCH2), 3.85 (s, 3H, PhOCH3).
3.28–3.38 (m, 2H, quinoline-H2), 2.63–2.65 (m, 2H, quinoline-H4),
4.1.4.1. 2-Phenylcarbonylmethylthio-6-((3,4-dihydroquinolin-
1(2H)-yl)methyl)pyrimidin-4(3H)-one (6a1).
Recrystallized
from EtOH/DMF as a brown crystal, yield: 48.6%, mp: 160–163 °C
(dec). 1H NMR (DMSO-d6, ppm) d: 12.72 (s, 1H, NH), 8.04 (d, 2H,
J = 7.8 Hz, PhH), 7.69 (t, 1H, J1 = 7.8 Hz, J2 = 15.6 Hz, PhH),7.58 (t,
2H, J1 = 7.8 Hz, J2 = 15.6 Hz, PhH), 6.23–6.86 (m, 4H, quinoline-H),
5.86 (s, 1H, C5-H), 4.77 (s, 2H, SCH2), 3.99 (s, 2H, NCH2), 3.24–
3.26 (m, 2H, quinoline-H2), 2.61–2.63 (m, 2H, quinoline-H4),
1.78–1.80 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3416 (NH),
2931, 2838 (CH3, CH2), 1656 (C@O), 1610 (C@O), 1599, 1574,
1535, 1507 (aryl), 1259 (C–N), 1172 (C–N). ESI-MS: m/z 422.54
(M+1). C23H23N3O3S (421.51).
1.75–1.77 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3315 (NH),
2945, 2846 (CH2), 1703 (C@O), 1654 (C@O), 1598, 1575, 1541,
4.1.4.7. 2-(4-Fluorophenylcarbonylmethylthio)-6-((3,4-dihydro-
1499 (aryl), 1239 (C–N), 1204 (C–N). ESI-MS: m/z 392.47 (M+1).
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
C
22H21N3O2S (391.49).
(6a7).
Recrystallized from EtOH/DMF as a brown needle crys-
tal, yield: 47.1%, mp: 180–181 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.73 (s, 1H, NH), 8.10–8.13 (m, 2H, PhH), 7.37–7.40 (m, 2H, PhH),
6.23–6.86 (m, 4H, quinoline-H), 5.85 (s, 1H, C5-H), 4.74 (s, 2H,
SCH2), 4.19 (s, 2H, NCH2) 3.26–3.33 (m, 2H, quinoline-H2), 2.62–
2.64 (m, 2H, quinoline-H4), 1.77–1.81 (m, 2H, quinoline-H3). IR
4.1.4.2.2-(4-Methylphenylcarbonylmethylthio)-6-((3,4-dihydro-
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6a2).
Recrystallized from EtOH/DMF as a brown crystal,
yield: 54.1%, mp: 165–166 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.68 (s, 1H, NH), 7.93 (d, 2H, J = 7.8 Hz, PhH), 7.36 (d, 2H,
J = 7.8 Hz, PhH), 6.24–6.87 (m, 4H, quinoline-H), 5.87 (s, 1H, C5-
H), 4.74 (s, 2H, SCH2), 4.02 (s, 2H, NCH2), 3.26–3.31 (m, 2H, quino-
line-H2), 2.71–2.73 (m, 2H, quinoline-H4), 2.39 (s, 3H, PhCH3),
(KBr, cmꢁ1
) m 3318 (NH), 2940, 2852 (CH2), 1702 (C@O), 1655
(C@O), 1597, 1575, 1539, 1502 (aryl), 1220 (C–N), 1154 (C–N).
ESI-MS: m/z 410.49 (M+1). C22H20FN3O2S (409.48).
1.76–1.78 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
)
m
3421 (NH),
4.1.4.8. 2-Benzylthio-6-((3,4-dihydroquinolin-1(2H)-yl)methyl)
2927, 2841 (CH3, CH2), 1675 (C@O), 1655 (C@O), 1602, 1538,
1506, 1459 (aryl), 1315 (C–N), 1200 (C–N). ESI-MS: m/z 406.47
(M+1). C23H23N3O2S (405.51).
pyrimidin-4(3H)-one (6a8).
Recrystallized from EtOH/DMF
as a brown crystal, yield: 49.6%, mp: 200–203 °C (dec). 1H NMR
(DMSO-d6, ppm) d: 12.70 (s, 1H, NH), 7.39 (d, 2H, J = 7.2 Hz,
PhH), 7.30 (t, 1H, J1 = 7.2 Hz, J2 = 14.4 Hz, PhH), 7.26 (t, 2H,
J1 = 7.2 Hz, J2 = 14.4 Hz, PhH), 6.35–6.90 (m, 4H, quinoline-H),
5.84 (s, 1H, C5-H), 4.38 (s, 2H, SCH2), 4.29 (s, 2H, NCH2), 3.42–
3.44 (m, 2H, quinoline-H2), 2.70–2.72 (m, 2H, quinoline-H4),
4.1.4.3. 2-(4-Chlorophenylcarbonylmethylthio)-6-((3,4-dihydro-
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6a3).
Recrystallized from EtOH/DMF as a brown crystal,
yield: 37.9%, mp: 193–195 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.79 (s, 1H, NH), 8.05 (d, 2H, J = 8.4 Hz, PhH), 7.64 (d, 2H,
J = 8.4 Hz, PhH), 6.22–6.86 (m, 4H, quinoline-H), 5.87 (s, 1H, C5-
H), 4.75 (s, 2H, SCH2), 3.99 (s, 2H, NCH2), 3.25–3.33 (m, 2H, quino-
line-H2), 2.62–2.64 (m, 2H, quinoline-H4), 1.76–1.78 (m, 2H, quin-
1.90–1.92 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3426 (NH),
2928, 2844 (CH2), 1656 (C@O), 1602, 1574, 1547, 1508 (aryl),
1310 (C–N), 1246 (C–N). ESI-MS: m/z 364.57 (M+1). C21H21N3OS
(363.48).
oline-H3). IR (KBr, cmꢁ1
)
m
3522 (NH), 2927, 2843 (CH2), 1690
4.1.4.9. 2-(4-Methylbenzylthio)-6-((3,4-dihydroquinolin-1(2H)-
(C@O), 1656 (C@O), 1600, 1587, 1545, 1503 (aryl), 1310 (C–N),
yl)methyl)pyrimidin-4(3H)-one (6a9).
Recrystallized from
1195 (C–N). ESI-MS: m/z 426.87 (M+1). C22H20ClN3O2S (425.93).
EtOH/DMF as a brown crystal, yield: 53.2%, mp: 185–186 °C
(dec). 1H NMR (DMSO-d6, ppm) d: 12.60 (s, 1H, NH), 7.27 (d, 2H,
J = 7.8 Hz, PhH), 7.10 (d, 2H, J = 7.8 Hz, PhH), 6.34–6.91 (m, 4H,
quinoline-H), 5.89 (s, 1H, C5-H), 4.33 (s, 2H, SCH2), 4.28 (s, 2H,
NCH2), 3.41–3.44 (m, 2H, quinoline-H2), 2.70-2.73 (m, 2H, quino-
line-H4), 2.27 (s, 3H, PhCH3), 1.90–1.91 (m, 2H, quinoline-H3). IR
4.1.4.4. 2-(4-Nitrophenylcarbonylmethylthio)-6-((3,4-dihydro-
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6a4).
Recrystallized from EtOH/DMF as an amber crystal,
yield: 45.1%, mp: 215–216 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.37 (s, 1H, NH), 8.27 (d, 2H, J = 8.4 Hz, PhH), 8.03 (d, 2H,
(KBr, cmꢁ1
) m 3418 (NH), 2921, 2849 (CH3, CH2), 1651 (C@O),

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J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
1602, 1579, 1534, 1508 (aryl), 1310 (C–N), 1194 (C–N). ESI-MS: m/
z 378.57 (M+1). C22H23N3OS (377.50).
yield: 45.4%, mp: 188–189 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.77 (s, 1H, NH), 7.86 (d, 2H, J = 7.8 Hz, PhH), 7.69 (t, 1H,
J1 = 7.8 Hz, J2 = 15.6 Hz, PhH),7.54 (t, 2H, J1 = 7.8 Hz, J2 = 15.6 Hz,
PhH), 6.29–6.82 (m, 4H, quinoline-H), 4.61 (s, 2H, SCH2), 4.21 (s,
2H, NCH2), 3.16–3.18 (m, 2H, quinoline-H2), 2.43–2.45 (m, 2H,
quinoline-H4), 1.95 (s, 3H, C5CH3), 1.60–1.61 (m, 2H, quinoline-
4.1.4.10. 2-(4-Chlorobenzylthio)-6-((3,4-dihydroquinolin-1(2H)-
yl)methyl)pyrimidin-4(3H)-one (6a10).
Recrystallized from
EtOH/DMF as a brown crystal, yield: 57.9%, mp: 190–193 °C
(dec). 1H NMR (DMSO-d6, ppm) d: 12.65 (s, 1H, NH), 7.41 (d, 2H,
J = 8.4 Hz, PhH), 7.33 (d, 2H, J = 8.4 Hz, PhH), 6.33–6.90 (m, 4H,
quinoline-H), 5.90 (s, 1H, C5-H), 4.36 (s, 2H, SCH2), 4.28 (s, 2H,
NCH2), 3.41–3.44 (m, 2H, quinoline-H2), 2.70–2.72 (m, 2H, quino-
H3). IR (KBr, cmꢁ1
) m 3420 (NH), 2922, 2842 (CH3, CH2), 1682
(C@O), 1637 (C@O), 1601, 1572, 1506, 1449 (aryl), 1262 (C–N),
1194 (C–N). ESI-MS: m/z 406.47 (M+1). C23H23N3O2S (405.51).
line-H4), 1.88–1.92 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
)
m
3413
4.1.4.16. 5-Methyl-2-(4-methylphenylcarbonylmethylthio)-6-
(NH), 2921, 2850 (CH2), 1648 (C@O), 1602, 1581, 1535 (aryl),
1310 (C–N), 1194 (C–N). ESI-MS: m/z 398.74 (M+1). C21H20ClN3OS
(397.92).
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b2).
Recrystallized from EtOH/DMF as a brown crystal,
yield: 52.3%, mp: 203–204 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.71 (s, 1H, NH), 7.76 (d, 2H, J = 8.4 Hz, PhH), 7.31 (d, 2H,
J = 8.4 Hz, PhH), 6.31–6.83 (m, 4H, quinoline-H), 4.56 (s, 2H,
SCH2), 4.21 (s, 2H, NCH2), 3.16–3.18 (m, 2H, quinoline-H2), 2.39
(s, 3H, PhCH3), 2.47–2.50 (m, 2H, quinoline-H4), 1.95 (s, 3H, C5-
4.1.4.11. 2-(4-Nitrobenzylthio)-6-((3,4-dihydroquinolin-1(2H)-
yl)methyl)pyrimidin-4(3H)-one (6a11).
Recrystallized from
EtOH/DMF as a amber crystal, yield: 51.5%, mp: 180–182 °C
(dec). 1H NMR (DMSO-d6, ppm) d: 12.70 (s, 1H, NH), 8.13 (d, 2H,
J = 8.4 Hz, PhH), 7.66 (d, 2H, J = 8.4 Hz, PhH), 6.30–6.89 (m, 4H,
quinoline-H), 5.90 (s, 1H, C5-H), 4.47 (s, 2H, SCH2), 4.28 (s, 2H,
NCH2), 3.39–3.43 (m, 2H, quinoline-H2), 2.68–2.71 (m, 2H, quino-
CH3), 1.62–1.66 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3428
(NH), 2940, 2920, 2832 (CH3, CH2), 1704 (C@O), 1633 (C@O),
1603, 1571, 1550, 1505 (aryl), 1265 (C–N), 1198 (C–N). ESI-MS:
m/z 420.74 (M+1). C24H25N3O2S (419.54).
line-H4), 1.87–1.91 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3370
(NH), 2930, 2841 (CH2), 1660 (C@O), 1600, 1583, 1518 (aryl),
1310 (C–N), 1240 (C–N). ESI-MS: m/z 409.51 (M+1). C21H20N4O3S
(408.47).
4.1.4.17.
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b3).
5-Methyl-2-(4-chlorophenylcarbonylmethylthio)-6-
Recrystallized from EtOH/DMF as a brown crystal,
yield: 36.7%, mp: 187–188 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.79 (s, 1H, NH), 7.85 (d, 2H, J = 8.4 Hz, PhH), 7.58 (d, 2H,
J = 8.4 Hz, PhH), 6.28–6.81 (m, 4H, quinoline-H), 4.58 (s, 2H,
SCH2), 4.20 (s, 2H, NCH2), 3.15–3.17 (m, 2H, quinoline-H2), 2.43–
2.50 (m, 2H, quinoline-H4), 1.95 (s, 3H, C5-CH3), 1.62–1.68 (m,
4.1.4.12. 2-(4-Cyanobenzylthio)-6-((3,4-dihydroquinolin-1(2H)-
yl)methyl)pyrimidin-4(3H)-one (6a12).
Recrystallized from
EtOH/DMF as a brown crystal, yield: 54.0%, mp: 186–188 °C
(dec). 1H NMR (DMSO-d6, ppm) d: 12.71 (s, 1H, NH), 7.73 (d, 2H,
J = 7.8 Hz, PhH), 7.59 (d, 2H, J = 7.8 Hz, PhH), 6.30–6.90 (m, 4H,
quinoline-H), 5.90 (s, 1H, C5-H), 4.43 (s, 2H, SCH2), 4.27 (s, 2H,
NCH2), 3.38–3.40 (m, 2H, quinoline-H2), 2.69–2.71 (m, 2H, quino-
2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3434 (NH), 2929, 2842 (CH3,
CH2), 1681 (C@O), 1637 (C@O), 1600, 1587, 1550, 1504 (aryl),
1256 (C–N), 1193 (C–N). ESI-MS: m/z 440.87 (M+1). C23H22ClN3O2S
(439.96).
line-H4), 1.87–1.91 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3419
(NH), 2927, 2840 (CH2), 2227 (C„N), 1656 (C@O), 1601, 1581,
1533, 1504 (aryl), 1311 (C–N), 1235 (C–N). ESI-MS: m/z 389.52
(M+1). C22H20N4OS (388.49).
4.1.4.18.
5-Methyl-2-(4-nitrophenylcarbonylmethylthio)-6-
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b4).
Recrystallized from EtOH/DMF as a amber crystal, yield:
4.1.4.13.
2-(4-Methoxybenzylthio)-6-((3,4-dihydroquinolin-
(6a13). Recrystal-
39.1%, mp: 189–190 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.81 (s,
1H, NH), 8.27 (d, 2H, J = 7.8 Hz, PhH), 8.09 (d, 2H, J = 7.8 Hz, PhH),
6.28–6.79 (m, 4H, quinoline-H), 4.65 (s, 2H, SCH2), 4.18 (s, 2H,
NCH2), 3.40–3.43 (m, 2H, quinoline-H2), 2.50–2.51 (m, 2H, quino-
line-H4), 1.89–1.94 (m, 2H, quinoline-H3), 1.620 (s, 3H, C5-CH3). IR
1(2H)-yl)methyl)pyrimidin-4(3H)-one
lized from EtOH/DMF as a brown crystal, yield: 48.7%, mp: 194–
196 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.60 (s, 1H, NH), 7.31
(d, 2H, J = 9.0 Hz, PhH), 6.91 (d, 2H, J = 9.0 Hz, PhH), 6.35–6.84
(m, 4H, quinoline-H), 5.89 (s, 1H, C5-H), 4.32 (s, 2H, SCH2), 4.29
(s, 2H, NCH2), 3.72 (s, 3H, PhOCH3), 3.42–3.45 (m, 2H, quinoline-
H2), 2.70–2.73 (m, 2H, quinoline-H4), 1.89–1.93 (m, 2H, quino-
(KBr, cmꢁ1
) m 3406 (NH), 2918, 2842 (CH3, CH2), 1696 (C@O), 1641
(C@O), 1602, 1524, 1505, 1458 (aryl), 1344 (C–N), 1189 (C–N). ESI-
MS: m/z 451.43 (M+1). C23H22N4O4S (450.51).
line-H3). IR (KBr, cmꢁ1
) m 3426 (NH), 2928, 2835 (CH3, CH2),
1649 (C@O), 1603, 1579, 1534, 1510 (aryl), 1311 (C–N), 1246 (C–
4.1.4.19.
5-Methyl-2-(4-cyanophenylcarbonylmethylthio)-6-
N). ESI-MS: m/z 394.53 (M+1). C22H23N3O2S (393.50).
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b5).
Recrystallized from EtOH/DMF as a brown crystal,
4.1.4.14. 2-(4-Fluorobenzylthio)-6-((3,4-dihydroquinolin-1(2H)-
yield: 36.6%, mp: 179–180 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.73 (s, 1H, NH), 7.63–7.96 (m, 4H, PhH), 6.30–6.80 (m, 4H, quin-
oline-H), 4.62 (s, 2H, SCH2), 4.19 (s, 2H, NCH2), 3.14–3.23 (m, 2H,
quinoline-H2), 2.44–2.50 (m, 2H, quinoline-H4), 1.94 (s, 3H, C5-
yl)methyl)pyrimidin-4(3H)-one (6a14).
Recrystallized from
EtOH/DMF as a brown needle crystal, yield: 53.9%, mp: 203–
205 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.66 (s, 1H, NH), 7.31
(d, 2H, J = 9.0 Hz, PhH), 6.91 (d, 2H, J = 9.0 Hz, PhH), 6.35–6.84
(m, 4H, quinoline-H), 5.89 (s, 1H, C5-H), 4.36 (s, 2H, SCH2), 4.29
(s, 2H, NCH2), 3.41–3.43 (m, 2H, quinoline-H2), 2.70–2.72 (m, 2H,
CH3), 1.62–1.78 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3442
(NH), 2919, 2840 (CH3, CH2), 2231 (C„N), 1690 (C@O), 1643
(C@O), 1602, 1544, 1505 (aryl), 1267 (C–N), 1195 (C–N). ESI-MS:
m/z 431.59 (M+1). C24H22N4O2S (430.52).
quinoline-H4), 1.90–1.91 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m
3319 (NH), 2923, 2844 (CH2), 1649 (C@O), 1600, 1577, 1545,
1508 (aryl), 1313 (C–N), 1229 (C–N). ESI-MS: m/z 382.49 (M+1).
4.1.4.20. 5-Methyl-2-(4-methoxylphenylcarbonylmethylthio)-
C21H20FN3OS (381.47).
6-((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b6).
Recrystallized from EtOH/DMF as a brown crystal,
4.1.4.15.
droquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b1). Recrystallized from EtOH/DMF as a brown crystal,
5-Methyl-2-phenylcarbonylmethylthio-6-((3,4-dihy-
yield: 38.9%, mp: 210–211 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.72 (s, 1H, NH), 7.83 (d, 2H, J = 8.4 Hz, PhH), 7.03 (d, 2H,
J = 8.4 Hz, PhH), 6.31–6.83 (m, 4H, quinoline-H), 4.54 (s, 2H,

J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
4373
SCH2), 4.23 (s, 2H, NCH2), 3.86 (s, 3H, PhOCH3), 3.20–3.22 (m, 2H,
quinoline-H2), 2.47–2.50 (m, 2H, quinoline-H4), 1.95 (s, 3H, C5-
1516 (aryl), 1344 (C–N), 1263 (C–N). ESI-MS: m/z 423.57 (M+1).
22H22N4O3S (422.50).
C
CH3), 1.64–1.66 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3225
(NH), 2932, 2839 (CH3, CH2), 1667 (C@O), 1646 (C@O), 1599,
1574, 1546, 1502 (aryl), 1266 (C–N), 1165 (C–N). ESI-MS: m/z
436.71 (M+1). C24H25N3O3S (435.54).
4.1.4.26. 5-Methyl-2-(4-cyanobenzylthio)-6-((3,4-dihydroquino-
lin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6b12). Recrys-
tallized from EtOH/DMF as a brown crystal, yield: 50.4%, mp:
195–197 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.70(s, 1H, NH),
7.54 (d, 2H, J = 7.8 Hz, PhH), 7.27 (d, 2H, J = 7.8 Hz, PhH), 6.40–
6.90 (m, 4H, quinoline-H), 4.38 (s, 2H, SCH2), 4.25 (s, 2H, NCH2),
3.37–3.39 (m, 2H, quinoline-H2), 2.57–2.59 (m, 2H, quinoline-H4),
4.1.4.21.
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b7).
5-Methyl-2-(4-fluorophenylcarbonylmethylthio)-6-
Recrystallized from EtOH/DMF as a crystal, yield:
47.6%, mp: 179–180 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.73
(s, 1H, NH), 7.90–7.93 (m, 2H, PhH), 7.33–7.36 (m, 2H, PhH),
6.29–6.81 (m, 4H, quinoline-H), 4.58 (s, 2H, SCH2), 4.21 (s, 2H,
NCH2), 3.16–3.18 (m, 2H, quinoline-H2), 2.43–2.45 (m, 2H, quino-
line-H4), 1.95 (s, 3H, C5-CH3), 1.61–1.63 (m, 2H, quinoline-H3). IR
1.98 (s, 3H, C5-CH3), 1.80–1.84 (m, 2H, quinoline-H3). IR (KBr, cm
ꢁ1
)
m 3433 (NH), 2935, 2842 (CH3, CH2), 2225 (C„N), 1642
(C@O), 1601, 1572, 1541, 1505 (aryl), 1260 (C–N), 1196 (C–N).
ESI-MS: m/z 403.57 (M+1). C23H22N4OS (402.51).
(KBr, cmꢁ1
)
m
3467 (NH), 2951, 2893, 2845 (CH3, CH2), 1703
4.1.4.27.
5-Methyl-2-(4-methoxybenzylthio)-6-((3,4-dihydro-
(C@O), 1654 (C@O), 1600, 1575, 1551, 1508 (aryl), 1263 (C–N),
1195 (C–N). ESI-MS: m/z 424.56 (M+1). C23H22FN3O2S (423.50).
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6b13).
Recrystallized from EtOH/DMF as a brown crystal,
yield: 39.8%, mp: 180–182 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.59 (s, 1H, NH), 7.05 (d, 2H, J = 8.4 Hz, PhH), 6.91 (d, 2H,
J = 8.4 Hz, PhH), 6.41–6.84 (m, 4H, quinoline-H), 4.38 (s, 2H, SCH2),
4.10(s, 2H, NCH2), 3.68 (s, 3H, PhOCH3), 3.44–3.47 (m, 2H, quino-
line-H2), 2.62–2.64 (m, 2H, quinoline-H4), 1.98 (s, 3H, C5-CH3),
4.1.4.22. 5-Methyl-2-benzylthio-6-((3,4-dihydroquinolin-1(2H)-
yl)methyl)pyrimidin-4(3H)-one (6b8).
Recrystallized from
EtOH/DMF as a crystal, yield: 51.7%, mp: 224–225 °C (dec). 1H
NMR (DMSO-d6, ppm) d: 12.63 (s, 1H, NH), 7.20 (d, 2H, J = 7.2 Hz,
PhH), 7.17 (t, 1H, J1 = 7.2 Hz, J2 = 14.4 Hz, PhH),7.14 (t, 2H,
J1 = 7.2 Hz, J2 = 14.4 Hz, PhH), 6.42–6.90 (m, 4H, quinoline-H),
4.39 (s, 2H, SCH2), 4.15 (s, 2H, NCH2), 3.43–3.45 (m, 2H, quino-
line-H2), 2.61–2.63 (m, 2H, quinoline-H4), 1.98 (s, 3H, C5-CH3),
1.85–1.89 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
)
m
3413 (NH), 2928,
2833 (CH3, CH2), 1641 (C@O), 1601, 1571, 1545, 1511 (aryl), 1253
(C–N), 1198 (C–N). ESI-MS: m/z 408.57 (M+1).
(407.53).
C23H25N3O2S
1.84–1.86 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3427 (NH),
2942, 2838 (CH3, CH2), 1640 (C@O), 1602, 1573, 1554, 1508 (aryl),
1264 (C–N), 1197 (C–N). ESI-MS: m/z 378.56 (M+1). C22H23N3OS
(377.50).
4.1.4.28. 5-Methyl-2-(4-fluorobenzylthio)-6-((3,4-dihydroquin-
olin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6b14). Recrys-
tallized from EtOH/DMF as a brown crystal, yield: 55.8%, mp:
215–217 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.63 (s, 1H, NH),
7.14 (m, 2H, PhH), 6.93 (m, 2H, PhH), 6.41–6.90 (m, 4H, quino-
line-H), 4.38 (s, 2H, SCH2), 4.16 (s, 2H, NCH2), 3.42–3.44 (m, 2H,
quinoline-H2), 2.61–2.63 (m, 2H, quinoline-H4), 1.98 (s, 3H, C5-
4.1.4.23. 5-Methyl-2-(4-methylbenzylthio)-6-((3,4-dihydroquin-
olin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6b9).
Recrys-
tallized from EtOH/DMF as a crystal, yield: 35.0%, mp: 223–
225 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.35 (s, 1H, NH), 7.01
(d, 2H, J = 7.8 Hz, PhH), 6.96 (d, 2H, J = 7.8 Hz, PhH), 6.58–6.61
(m, 4H, quinoline-H), 4.22 (s, 2H, SCH2), 4.12(s, 2H, NCH2), 3.43–
3.45 (m, 2H, quinolineH2), 2.61–2.63 (m, 2H, quinoline-H4), 2.24
(s, 3H, PhCH3), 1.97 (s, 3H, C5-CH3), 1.84–1.86 (m, 2H, quinoline-
CH3), 1.83–1.87 (m, 2H, quinoline-H3). IR (KBr, cmꢁ1
) m 3459
(NH), 2939, 2840 (CH3, CH2), 1641 (C@O), 1601, 1573, 1554,
1508 (aryl), 1265 (C–N), 1222 (C–N). ESI-MS: m/z 396.53 (M+1).
C22H22FN3OS (395.49).
H3). IR (KBr, cmꢁ1
) m 3334 (NH), 2926, 2853 (CH3, CH2), 1683
(C@O), 16001, 1538, 1497 (aryl), 1239 (C–N), 1190 (C–N). ESI-
MS: m/z 392.53 (M+1). C23H25N3OS (391.53).
4.1.4.29. 5-Ethyl-2-phenylcarbonylmethylthio-6-((3,4-dihydro-
quinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6c1).
Recrystallized from EtOH/DMF as a brown crystal,
yield: 47.5%, mp: 193–194 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.77 (s, 1H, NH),7.85 (d, 2H, J = 7.8 Hz, PhH), 7.68 (t, 1H,
J1 = 7.8 Hz, J2 = 15.6 Hz, PhH), 7.53 (t, 2H, J1 = 7.8 Hz, J2 = 15.6 Hz,
PhH), 6.32–6.82 (m, 4H, quinoline-H), 4.60 (s, 2H, SCH2), 4.24 (s,
2H, NCH2), 3.16–3.18 (m, 2H, quinoline-H2), 2.45–2.50 (m, 2H,
quinoline-H4), 2.43 (q, 2H, J = 7.8 Hz, C5-CH2CH3), 1.60–1.63 (m,
4.1.4.24. 5-Methyl-2-(4-chlorobenzylthio)-6-((3,4-dihydroquin-
olin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6b10).
Recrys-
tallized from EtOH/DMF as a crystal, yield: 56.3%, mp: 220–
222 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.64 (s, 1H, NH), 7.15
(d, 2H, J = 7.8 Hz, PhH), 7.11 (d, 2H, J = 7.8 Hz, PhH), 6.40–6.91
(m, 4H, quinolineH), 4.38 (s, 2H, SCH2), 4.17 (s, 2H, NCH2), 3.41–
3.43 (m, 2H, quinolineH2), 2.60–2.62 (m, 2H, quinolineH4), 1.98
2H, quinoline-H3), 1.05 (t, 3H, J = 7.8 Hz, C5-CH2CH3). IR (KBr, cm
ꢁ1
)
m 3462 (NH), 2931, 2840 (CH3, CH2), 1682 (C@O), 1633(C@O),
(s, 3H, C5CH3), 1.82–1.86 (m, 2H, quinolineH3). IR (KBr, cmꢁ1
) m
1599, 1573, 1507, 1448 (aryl), 1254 (C–N), 1195 (C–N). ESI-MS:
m/z 420.21 (M+1). C24H25N3O2S (419.54).
3426 (NH), 2941, 2840 (CH3, CH2), 1641 (C@O), 1601, 1573,
1554, 1507 (aryl), 1265 (C–N), 1197 (C–N). ESI-MS: m/z 412.56
(M+1). C22H22ClN3OS (411.95).
4.1.4.30.
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6c2). Recrystallized from EtOH/DMF as a brown crystal,
5-Ethyl-2-(4-methylphenylcarbonylmethylthio)-6-
4.1.4.25. 5-Methyl-2-(4-nitrobenzylthio)-6-((3,4-dihydroquino-
lin-1(2H)-yl)methyl) pyrimidin-4(3H)-one (6b11).
Recrys-
yield: 57.1%, mp: 185–187 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.76 (s, 1H, NH),7.74 (d, 2H, J = 8.4 Hz, PhH), 7.32 (d, 2H,
J = 8.4 Hz, PhH), 6.33–6.83 (m, 4H, quinoline-H), 4.56 (s, 2H,
SCH2), 4.24 (s, 2H, NCH2), 3.16–3.18 (m, 2H, quinoline-H2), 2.45–
2.50 (m, 2H, quinoline-H4), 2.42 (q, 2H, J = 7.2 Hz, C5-CH2CH3),
2.39 (s, 3H, PhCH3), 1.62–1.65 (m, 2H, quinoline-H3), 1.02 (t, 3H,
tallized from EtOH/DMF as a amber crystal, yield: 52.9%, mp:
209–210 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.69 (s, 1H, NH),
7.93 (d, 2H, J = 8.4 Hz, PhH), 7.34 (d, 2H, J = 8.4 Hz, PhH), 6.39–
6.91 (m, 4H, quinoline-H), 4.39 (s, 2H, SCH2), 4.32 (s, 2H, NCH2),
3.39–3.40 (m, 2H, quinoline-H2), 2.57–2.59 (m, 2H, quinoline-H4),
1.98 (s, 3H, C5-CH3), 1.80–1.84 (m, 2H, quinoline-H3). IR (KBr, cm
J = 7.2 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
(CH3, CH2), 1677 (C@O), 1639 (C@O), 1602, 1572, 1505, 1456 (aryl),
) m 3437 (NH), 2929, 2842
ꢁ1
)
m 3334 (NH), 2936, 2842 (CH3, CH2), 1643 (C@O), 1599, 1573,

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J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
1254 (C–N), 1193 (C–N). ESI-MS: m/z 434.57 (M+1). C25H27N3O2S
(433.18).
(C@O), 1598, 1574, 1547, 1506 (aryl), 1253 (C–N), 1196 (C–N).
ESI-MS: m/z 438.56 (M+1). C24H24FN3O2S (437.16).
4.1.4.31.
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6c3). Recrystallized from EtOH/DMF as a brown crystal,
5-Ethyl-2-(4-chlorophenylcarbonylmethylthio)-6-
4.1.4.36. 5-Ethyl-2-benzylthio-6-((3,4-dihydroquinolin-1(2H)-
yl)methyl)pyrimidin-4(3H)-one (6c8).
Recrystallized from
EtOH/DMF as a brown crystal, yield: 46.9%, mp: 224–226 °C
(dec). 1H NMR (DMSO-d6, ppm) d: 12.62 (s, 1H, NH), 7.20 (d, 2H,
J = 7.2 Hz, PhH), 7.18 (t, 1H, J1 = 7.2 Hz, J2 = 14.4 Hz, PhH),7.14 (t,
2H, J1 = 7.2 Hz, J2 = 14.4 Hz, PhH), 6.34–6.91 (m, 4H, quinoline-H),
4.42 (s, 2H, SCH2), 4.14 (s, 2H, NCH2), 3.42–3.44 (m, 2H, quino-
line-H2), 2.61–2.63 (m, 2H, quinoline-H4), 2.46-2.51 (q, 2H,
J = 7.8 Hz, C5-CH2CH3), 1.84–1.86 (m, 2H, quinoline-H3), 1.06 (t,
yield: 39.2%, mp: 190–192 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.48 (s, 1H, NH), 7.84 (d, 2H, J = 8.4 Hz, PhH), 7.57 (d, 2H,
J = 8.4 Hz, PhH), 6.31–7.01 (m, 4H, quinoline-H), 4.57 (s, 2H,
SCH2), 4.24 (s, 2H, NCH2), 3.24–3.33 (m, 2H, quinoline-H2), 2.67–
2.71 (m, 2H, quinoline-H4), 2.31 (q, 2H, J = 7.2 Hz, C5-CH2CH3),
1.87–1.91 (m, 2H, quinoline-H3), 1.06 (t, 3H, J = 7.2 Hz, C5-CH2CH3).
IR (KBr, cmꢁ1
)
m
3566 (NH), 2962, 2930, 2868 (CH3, CH2), 1686
3H, J = 7.8 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
) m 3361 (NH), 2932,
(C@O), 1640 (C@O), 1601, 1571, 1536, 1506 (aryl), 1254 (C–N),
1191 (C–N). ESI-MS: m/z 454.43 (M+1). C24H24ClN3O2S (454.13).
2840 (CH3, CH2), 1635 (C@O), 1600, 1570, 1549, 1508 (aryl),
1252 (C–N), 1197 (C–N). ESI-MS: m/z 392.37 (M+1). C23H25N3OS
(391.53).
4.1.4.32. 5-Ethyl-2-(4-nitrophenylcarbonylmethylthio)-6-((3,4-
dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
4.1.4.37. 5-Ethyl-2-(4-methylbenzylthio)-6-((3,4-dihydroquino-
(6c4).
Recrystallized from EtOH/DMF as a amber crystal,
lin-1(2H)-yl)methyl)pyrimidin -4(3H)-one (6c9).
Recrystal-
yield: 43.7%, mp: 191–192 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.78 (s, 1H, NH), 8.27 (d, 2H, J = 7.8 Hz, PhH), 8.04 (d, 2H,
J = 7.8 Hz, PhH), 6.32–7.01 (m, 4H, quinoline-H), 4.64 (s, 2H,
SCH2), 4.23 (s, 2H, NCH2), 3.32–3.34 (m, 2H, quinoline-H2), 2.71–
2.73 (m, 2H, quinoline-H4), 2.43 (q, 2H, J = 7.8 Hz, C5-CH2CH3),
1.89–1.90 (m, 2H, quinoline-H3), 1.07 (t, 3H, J = 7.8 Hz, C5-CH2CH3).
lized from EtOH/DMF as a brown crystal, yield: 47.2%, mp: 218–
221 °C(dec). 1H NMR (DMSO-d6, ppm) d: 12.60 (s, 1H, NH), 7.00
(d, 2H, J = 8.4 Hz, PhH), 6.97 (d, 2H, J = 8.4 Hz, PhH), 6.43–6.90
(m, 4H, quinoline-H), 4.41 (s, 2H, SCH2), 4.09 (s, 2H, NCH2), 3.42–
3.44 (m, 2H, quinoline-H2), 2.61–2.64 (m, 2H, quinoline-H4),
2.46–2.51 (q, 2H, J = 7.8 Hz, C5-CH2CH3), 2.22 (s, 3H, PhCH3),
1.84–1.88 (m, 2H, quinoline-H3), 1.07 (t, 3H, J = 7.8 Hz, C5-CH2CH3).
IR (KBr, cmꢁ1
) m 3467 (NH), 2930, 2869 (CH3, CH2), 1693 (C@O),
1640 (C@O), 1601, 1571, 1536, 1506 (aryl), 1344 (C–N), 1189 (C–
IR (KBr, cmꢁ1
) m 3422 (NH), 2930, 2838, 2796 (CH3, CH2), 1634
N). ESI-MS: m/z 465.55 (M+1). C24H24N4O4S (464.15).
(C@O), 1600, 1569, 1546, 1507 (aryl), 1251 (C–N), 1197 (C–N).
ESI-MS: m/z 406.59 (M+1). C24H27N3OS (405.56).
4.1.4.33. 5-Ethyl-2-(4-cyanophenylcarbonylmethylthio)-6-((3,4-
dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
4.1.4.38. 5-Ethyl-2-(4-chlorobenzylthio)-6-((3,4-dihydroquino-
(6c5).
Recrystallized from EtOH/DMF as a brown crystal,
lin-1(2H)-yl)methyl) pyrimidin-4(3H)-one (6c10).
Recrys-
yield: 49.6%, mp: 192–194 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.80 (s, 1H, NH), 7.60–7.96 (m, 4H, PhH), 6.36–6.80 (m, 4H, quin-
oline-H), 4.61 (s, 2H, SCH2), 4.31 (s, 2H, NCH2), 3.33–3.42 (m, 2H,
quinoline-H2), 2.43–2.51 (m, 2H, quinoline-H4), 2.39 (q, 2H,
J = 7.2 Hz, C5-CH2CH3), 1.60–1.61 (m, 2H, quinoline-H3), 1.02 (t,
tallized from EtOH/DMF as a brown crystal, yield: 49.7%, mp:
227–229 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.65(s, 1H, NH),
7.15 (d, 2H, J = 8.4 Hz, PhH), 7.11 (d, 2H, J = 8.4 Hz, PhH), 6.42–
6.91 (m, 4H, quinoline-H), 4.41 (s, 2H, SCH2), 4.16 (s, 2H, NCH2),
3.40–3.42 (m, 2H, quinoline-H2), 2.60–2.62 (m, 2H, quinoline-H4),
2.47–2.50 (q, 2H, J = 7.8 Hz, C5-CH2CH3), 1.83–1.85 (m, 2H, quino-
3H, J = 7.2 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
) m 3343 (NH), 2937,
2869 (CH3, CH2), 2230 (C„N), 1688 (C@O), 1640 (C@O), 1601,
1542, 1506 (aryl), 1251 (C–N), 1195 (C–N). ESI-MS: m/z 445.54
(M+1). C25H24N4O2S (444.16).
line-H3), 1.06 (t, 3H, J = 7.8 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
) m 3326
(NH), 2932, 2840 (CH3, CH2), 1636 (C@O), 1600, 1570, 1546,
1507 (aryl), 1251 (C–N), 1197 (C–N). ESI-MS: m/z 426.74 (M+1).
C23H24ClN3OS (425. 97).
4.1.4.34. 5-Ethyl-2-(4-methoxylphenylcarbonylmethylthio)-6-
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
4.1.4.39.
5-Ethyl-2-(4-nitrobenzylthio)-6-((3,4-dihydroquino-
Recrystal-
(6c6).
Recrystallized from EtOH/DMF as a brown crystal,
lin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6c11).
yield: 39.1%, mp: 196–198 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.75 (s, 1H, NH), 7.82 (d, 2H, J = 8.4 Hz, PhH), 7.02(d, 2H,
J = 8.4 Hz, PhH), 6.33–6.83 (m, 4H, quinoline-H), 4.53 (s, 2H,
SCH2), 4.24 (s, 2H, NCH2), 3.86 (s, 3H, PhOCH3). 3.14–3.19 (m,
2H, quinoline-H2), 2.45–2.50 (m, 2H, quinoline-H4), 2.27–2.31 (q,
2H, J = 7.2 Hz, C5-CH2CH3), 1.88–1.90 (m, 2H, quinoline-H3), 1.05
lized from EtOH/DMF as a amber crystal, yield: 45.1%, mp: 195–
197 °C(dec). 1H NMR (DMSO-d6, ppm) d: 12.71 (s, 1H, NH), 7.93
(d, 2H, J = 8.4 Hz, PhH), 7.34 (d, 2H, J = 8.4 Hz, PhH), 6.42–6.91
(m, 4H, quinoline-H), 4.42 (s, 2H, SCH2), 4.31 (s, 2H, NCH2), 3.37–
3.39 (m, 2H, quinoline-H2), 2.56–2.58 (m, 2H, quinoline-H4), 2.50
(q, 2H, J = 7.2 Hz, C5-CH2CH3), 1.80–1.82 (m, 2H, quinoline-H3),
(t, 3H, J = 7.2 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
)
m
3476 (NH), 2932,
1.07 (t, 3H, J = 7.2 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
) m 3434 (NH),
2839 (CH3, CH2), 1667 (C@O), 1642 (C@O), 1599, 1564, 1541,
1504 (aryl), 1264 (C–N), 1166 (C–N). ESI-MS: m/z 450.34 (M+1).
2931, 2840 (CH3, CH2), 1641 (C@O), 1600, 1571, 1519 (aryl),
1250 (C–N), 1196 (C–N). ESI-MS: m/z 437.47 (M+1). C23H24ClN4O3S
(436. 53).
C25H27N3O3S (449.18).
4.1.4.35.
((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-one
(6c7).
5-Ethyl-2-(4-fluorophenylcarbonylmethylthio)-6-
4.1.4.40. 5-Ethyl-2-(4-cyanobenzylthio)-6-((3,4-dihydroquino-
lin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6c12).
Recrystal-
Recrystallized from EtOH/DMF as a brown needle crys-
lized from EtOH/DMF as a brown crystal, yield: 45.2%, mp: 195–
196 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.70 (s, 1H, NH), 7.54
(d, 2H, J = 8.4 Hz, PhH), 7.27 (d, 2H, J = 8.4 Hz, PhH), 6.42–6.91
(m, 4H, quinoline-H), 4.41 (s, 2H, SCH2), 4.24(s, 2H, NCH2), 3.36–
3.38 (m, 2H, quinoline-H2), 2.57–2.59 (m, 2H, quinoline-H4), 2.50
(q, 2H, J = 7.8 Hz, C5-CH2CH3), 1.80–1.83 (m, 2H, quinoline-H3),
tal, yield: 49.3%, mp: 192–193 °C (dec). 1H NMR (DMSO-d6, ppm) d:
12.84(s, 1H, NH), 7.90–7.92 (m, 2H, PhH), 7.32–7.35 (m, 2H, PhH),
6.32–6.82 (m, 4H, quinoline-H), 4.58 (s, 2H, SCH2), 4.24 (s, 2H,
NCH2), 3.33–3.44 (m, 2H, quinoline-H2), 2.39–2.50 (m, 2H, quino-
line-H4), 2.28–2.31 (q, 2H, J = 7.2 Hz, C5-CH2CH3), 1.62–1.71 (m,
2H, quinoline-H3), 1.05 (t, 3H, J = 7.2 Hz, C5-CH2CH3). IR (KBr, cm
1.07 (t, 3H, J = 7.8 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
2932, 2840 (CH3, CH2), 2227 (C„N), 1640 (C@O), 1601, 1571,
) m 3411 (NH),
ꢁ1
)
m 3466 (NH), 2933, 2840 (CH3, CH2), 1680 (C@O), 1638

J. Zhang et al. / Bioorg. Med. Chem. 19 (2011) 4366–4376
4375
1542, 1503 (aryl), 1251 (C–N), 1195 (C–N). ESI-MS: m/z 417.62
(M+1). C24H24N4OS (416.54).
protection from the cytopathic effect of the virus in infected cells
was defined as the 50% effective concentration (EC50).
4.1.4.41. 5-Ethyl-2-(4-methoxybenzylthio)-6-((3,4-dihydroquin-
4.4. RT inhibition assay
olin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6c13).
Recrys-
tallized from EtOH/DMF as a brown crystal, yield: 48.7%, mp:
187–188 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.58 (s, 1H, NH),
7.04 (d, 2H, J = 8.4 Hz, PhH), 6.91 (d, 2H, J = 8.4 Hz, PhH), 6.43–
6.84 (m, 4H, quinoline-H), 4.32 (s, 2H, SCH2), 4.41 (s, 2H, NCH2),
3.68 (s, 3H, PhOCH3), 3.45–3.47 (m, 2H, quinoline-H2), 2.62–2.64
(m, 2H, quinoline-H4), 2.50 (q, 2H, J = 8.4 Hz, C5-CH2CH3), 1.86–
1.88 (m, 2H, quinoline-H3), 1.06 (t, 3H, J = 8.4 Hz, C5-CH2CH3). IR
Compounds were tested for antiviral activity against HIV-1
wtRT, using a poly(ra)/oligo(dT)15 homopolymer template with
HIV antigen detection ELISA for quantifying expression of HIV-1
RT in culture medium. Oligo(dT) was immobilized via its
50-terminal phosphate to Covalink-NH microtiter plates. The bio-
tin-dUTP was incorporated by reverse transcriptase. The reaction
mixture contained 50 mmol/L Tris-HCl (pH 8.3), 3 mmol/L MgCl2,
(KBr, cmꢁ1
)
m
3434 (NH), 2930, 2833, 2763 (CH3, CH2), 1637
75 mmol/L KCl, 5 mmol/L DTT
(
DL-dithiothreitol), 0.13 mg/mL
M dTTP.
(C@O), 1600, 1569, 1544, 1509 (aryl), 1251 (C–N), 1197 (C–N).
ESI-MS: m/z 422.34 (M+1). C24H27N3O2S (421.56).
BSA, 10 g/mL poly (A), 0.75 M biotin-11-dUTP, and 1.5 l
l
l
After incubation at 37 °C for 1 h, the plate was washed three times
with a wash buffer containing 50 mmol/L Tris-HCl (pH 7.5),
0.15 mol/L NaCl, 0.05 mmol/L MgCl2, and 0.02% Tween-20. After
4.1.4.42. 5-Ethyl-2-(4-fluorobenzylthio)-6-((3,4-dihydroquino-
100
30 min at room temperature, the plate was washed with the same
buffer. Subsequently 50 L of SA-ALP (Alkaline Phosphatase Strep-
lL of 1% BSA was added to each well and incubated for
lin-1(2H)-yl)methyl)pyrimidin-4(3H)-one (6c14).
Recrystal-
lized from EtOH/DMF as a brown needle crystal, yield: 59.7%, mp:
224–227 °C (dec). 1H NMR (DMSO-d6, ppm) d: 12.63 (s, 1H, NH),
7.12 (d, 2H, J = 8.4 Hz, PhH), 6.93 (d, 2H, J = 8.4 Hz, PhH),
6.43–6.90 (m, 4H, quinoline-H), 4.42 (s, 2H, SCH2), 4.15 (s, 2H,
NCH2), 3.42–3.44 (m, 2H, quinoline-H2), 2.60–2.63 (m, 2H, quino-
line-H4), 2.51 (q, 2H, J = 7.2 Hz, C5-CH2CH3), 1.84–1.86 (m, 2H,
l
tavidin) solution (100 ng/mL) was added per well and then incu-
bated for 1 h at 37 °C. The plate was washed as above and to
which then was added 50 lL of PNPP (p-nitrophenyl phosphate,
disodium) (1 mg/mL, pH 9.5), after 30 min at 37 °C, the reaction
was stopped by addition of 0.5 M NaOH. The products were de-
tected and quantified using a colorimetric streptavidin alkaline
phosphatase reporter system.
quinoline-H3), 1.07 (t, 3H, J = 7.2 Hz, C5-CH2CH3). IR (KBr, cmꢁ1
) m
3359 (NH), 2932, 2841 (CH3, CH2), 1636 (C@O), 1600, 1570,
1547, 1508 (aryl), 1251 (C–N), 1221 (C–N). ESI-MS: m/z 410.29
(M+1). C23H24FN3OS (409.52).
Acknowledgments
4.3. Anti-HIV activity assays
Research work in the Chinese authors’ laboratory has been sup-
ported by the National Natural Science Foundation of China (NSFC
Nos. 30371686, 30772629, and 30873133), Key Project of The
International Cooperation, Ministry of Science and Technology of
China (2003DF000033) and Research Fund for the Doctoral
Program of Higher Education of China (070422083). We are grate-
ful to Kristien Erven and Kris Uyttersprot for excellent technical
assistance (Rega Institute).
Evaluation of the antiviral activity of the compounds against
HIV-1 strain IIIB and HIV-2 strain (ROD) in MT-4 cells was per-
formed using the MTT assay as previously described.19 Stock solu-
tions (10ꢀ final concentration) of test compounds were added in
25 lL volumes to two series of triplicate wells so as to allow simul-
taneous evaluation of their effects on mock- and HIV-infected cells
at the beginning of each experiment. Serial fivefold dilutions of test
compounds were made directly in flat-bottomed 96-well microti-
ter trays using a Biomek 3000 robot (Beckman instruments, Fuller-
ton, CA). Untreated control HIV- and mock-infected cell samples
were included for each sample. HIV-1(IIIB)20 or HIV-2 (ROD)21
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