Design, synthesis and biological evaluation of novel 7-mercaptocoumarin derivatives as α1-adrenoceptor antagonists

Article abstract of DOI:10.1248/cpb.c12-00531

Study on the pharmacophore model of α₁-adrenoceptor (α₁-AR) antagonists led to design a series of novel 7-mercaptocoumarin derivatives as α₁-AR antagonists. All designed compounds have been synthesized and biologically eva

Full text of DOI:10.1248/cpb.c12-00531

Regular Article
16
Vol. 61, No. 1
Chem. Pharm. Bull. 61(1) 16–24 (2013)
Design, Synthesis and Biological Evaluation of Novel
7-Mercaptocoumarin Derivatives as α1-Adrenoceptor Antagonists
Sai-Sai Xie, Xiao-Bing Wang,* Jiang-Yan Li, and Ling-Yi Kong*
State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical
University; 24 Tong Jia Xiang, Nanjing 210009, P.R. China.
Received June 17, 2012; accepted October 17, 2012
Study on the pharmacophore model of α1-adrenoceptor (α1-AR) antagonists led to design a series of
novel 7-mercaptocoumarin derivatives as α1-AR antagonists. All designed compounds have been synthesized
and biologically evaluated. The results showed that most of them exhibited strong antagonistic activity. Espe-
cially compound 6 showed excellent activity, which was better than that of the reference compound prazosin.
Structure–activity relationship studies revealed that small hydrophobic group at the terminal heterocyclic
ring and ortho substituents on the phenyl ring of phenylpiperazine moiety were the essential structural fac-
tors for α1-AR antagonistic activity. The pharmacophore modeling studies further clarified their structural
contributions to antagonistic activity and also demonstrated that 7-mercaptocoumarin moiety could be a use-
ful scaffold for design of α1-AR antagonists.
Key words α1-adrenoceptor antagonist; pharmacophore model; coumarin; phenylpiperazine
Benign prostatic hyperplasia (BPH) is a highly prevalent used in drug design. We and other groups have reported many
disorder, which increases dramatically with age. Although not compounds containing a coumarin moiety exhibited remark-
a life-threatening disease, BPH can significantly affect qual- able activities.19–26) However, it was interesting to note that al-
ity of life. BPH manifests clinically with lower urinary tract though bioisosterism was a commonly used technique in drug
symptoms (LUTS) and is associated with sexual dysfunction. research, rare reports focus on sulfur-containing coumarins.
As many as 60% of men aged 60 years have some degree of Very recently, Lee et al. reported a series of 7-mercaptocou-
clinical BPH. With the increases in the distribution of people marin derivatives as potent cytotoxic agents and most of them
over the age of 60, BPH is set to become an even greater prob- showed remarkable activity.27) This result indicated that sulfur-
lem in men’s health. The previous studies demonstrate that α1- containing coumarin could be a useful scaffold in drug design
adrenoceptors (α1-ARs) play a significant role in the treatment and also provoked our interest to design and develop some
of BPH, selective antagonism of α1-ARs can relax prostatic sulfur-containing coumarin derivatives. Our investigations
muscle tone and decrease the symptoms of BPH.1–5) Accord- found that 7-mercaptocoumarins with a hydrophobic group at
ingly, α1-AR antagonists are promising therapeutic agents for position 4 could fulfill the HBA and HY features of pharma-
treatment of BPH.6–14)
cophore model, so we hypothesized that 7-mercaptocouamrin
The α1-ARs belong to the superfamily of G-protein-coupled derivatives containing various substituted phenylpiperazine
seven transmembrane helix receptors (GPCR) and comprise moieties may meet the requirements of pharmacophore model
of three distinct subtypes that have been clearly identified and exhibit α1-AR antagonistic properties (Fig. 1b).
by both pharmacological and binding studies. To date, their
To explore this hypothesis, a series of new compounds 1–24
subtypes have been classified into, α1A, α1B, α1D and their characterized by linking 7-mercaptocoumarin with the substi-
corresponding cloned counterparts termed α1a, α1b, α1d, re- tuted phenylpiperazine moiety through ploymethylene spacer
spectively.15–17) Although α1-ARs have been intensively inves- have been designed, synthesized and evaluated for their α1-AR
tigated for last decades, their crystal structures were still not antagonistic activities. Moreover, in order to rationalize their
available, thus, the α1-AR antagonists usually been designed structure–activity relationships and to verify our hypothesis,
through ligand-based method. Recently, research efforts in the pharmacophore model of ideal α1-AR antagonists was also
the field of α1-AR antagonists have led to the identification of performed according to previous methods.
several pharmacophore models and most of them consisted of
five common features: one positive ionizable group (PI), one
Results and Discussion
hydrogen bond acceptor (HBA) and three hydrophobic fea-
Chemistry The new compounds 1–24 were synthesized
tures (HY1-3).6,7) Many phenylpiperazine derivatives contain- as showed in Chart 1. Condensation of resorcinol with eth-
ing different heterocyclic rings show high affinity for α1-ARs ylbenzoylacetate or ethylacetoacetate in 1,4-dioxane in the
and their chemical groups can also nicely map to the features presence of concentrated sulphuric acid produced compound
of the model.7–14) Usually, the HY1 and HY2 can be filled by 26 with high yield. After acylation of 26 with N,N-dimeth-
substituted phenyl ring of the phenylpiperazine moiety, while ylcarbamothioic chloride in anhydrous CH2Cl2 at room tem-
the latter satisfy the PI with its positive ionisable nitrogen perature with 4-dimethylaminopyridine as acid scavenger, the
atom. The remaining features, HBA and HY3, can be matched obtained compounds 27 were converted to 28 by a rearrange-
by hydrogen bond acceptor moiety and hydrophobic group of ment at 220–230°C, then hydrolysis with methanolic KOH and
a heterocyclic ring system, respectively6,13,14,18) (Fig. 1a).
acidification with concentrated hydrochloric acid to form key
Coumarin moiety as heterocyclic scaffold has been widely intermediate 29.28) Starting from 29 and α,ω-dibromoalkanes
having two to four methylene groups were employed to pre-
pare 30a–f, which in turn were converted to final compounds
The authors declare no conflict of interest.
© 2013 The Pharmaceutical Society of Japan
*To whom correspondence should be addressed. e-mail: xbwang@cpu.edu.cn; cpu_lykong@126.com

January 2013
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Fig. 1. The Pharmacophore Model of Barbaro et al.7) Mapped with an Example Phenylpiperazine Antagonist (a) and the Proposed Target
Molecules (b)
Features: hydrogen-bond acceptor (HBA), hydrophobic regions (HY1-3), and positive ionizable feature (PI). R1, R2: hydrophobic substituents.
Reagents and condition: (i) ethylbenzoylacetate or ethylacetoacetate, conc. H2SO4, 1,4-dioxane, 70°C, 4h, 90–92%. (ii) N, N-Dimethylcarbamothioic chloride, DMAP,
CH2Cl2, 96h, 83–84%. (iii) 220–230°C, 1h, 79–82%. (iv) KOH, MeOH, 1.5h, reflux, 72–75%. (v) Br(CH2)nBr (n=2–4), K2CO3, acetone, 4h, reflux, 61–70%. (vi) CH3CN,
K2CO3, 8h, reflux, 16–42%.
Chart 1
1–24 by reaction with substituted phenylpiperazine 31a–d in present compounds, the methyl or methoxy group was alter-
acetonitrile in the presence of anhydrous K2CO3.29)
nately introduced to para- or ortho-position. The activity data
Biological Activity The α1-AR antagonistic activities of showed that compounds (1–6, 13–18) with ortho-substituents
compounds 1–24 were evaluated by antagonism of phenyleph- on the phenyl ring exhibited 10–100 fold more potent activity
rine-induced contractions of rat anococcygeus smooth muscles than the corresponding compounds (7–12, 19–24) with para
according to previous reports.30–35) The rat anococcygeus substituents except compound 9. This suggested that ortho-
smooth muscles were selected as muscle preparations because position of phenyl ring was critical to antagonistic activity of
their contractions are primarily mediated by α1-ARs, and they present compounds. For most compounds, replacement of the
have neither spontaneous activity nor tone and can survive methoxy group with a methyl slightly enhanced the activity,
for a long time in vitro.36–39) The activity was expressed as suggesting that increasing the hydrophobicity of substituent
pA2=−log[1–24]2, in which [1–24]2 is defined as the measured on phenyl ring was more favorable to the antagonistic activity.
concentrations of the compounds 1–24 according to Schild’s The effects of different sizes of hydrophobic substituents at
methods.40) The obtained pA2 values of compounds 1–24 and the terminal heterocyclic ring on the antagonistic activity were
the reference compound prazosin were listed in Table 1. From also investigated by introducing phenyl group or methyl group
the antagonistic activity data, it can be seen that most of syn- to the position 4 of coumarin moiety. As shown in Table 1,
thesized compounds (1–6, 9, 13–18) exhibited strong α1-AR with exception of compounds 7 and 8, most 4-methylcouamrin
antagonistic activity, with pA2 values ranging from 8.005 to derivatives 1–12 were found to be more potent than the cor-
9.365. Especially compounds 6 exhibited the most potent ac- responding 4-phenylcouamrin derivatives 13–24, in particular,
tivity, with pA2 value of 9.365, which was more potent than the activities of compounds 5, 6 and 9 were 10-times stronger
reference compound prazosin. Only compounds 7 and 8 were than those of their 4-phenylcoumarin analogues 17, 18 and
found to be the weakest antagonists, giving pA2 value of 6.531 21. These results indicated that a small hydrophobic group
and 6.243, respectively.
at the terminal heterocyclic ring was more beneficial for the
Results from previous studies indicated that substitutions on α1-AR antagonistic activity. Finally, the length of methylene
the phenyl ring of phenylpiperazine moiety could significantly linker between the 7-mercaptocoumarin and phenylpiperazine
affect the antagonistic activity.7,14,41) To clarify their effects in moiety was changed from 2 carbon atoms to 4, to investigate

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Vol. 61, No. 1
Table 1. Fit Values Based on the Pharmacophore Model and α1-ARs Antagonistic Activities of Compounds 1–24
R1
R2
pA2
Fit valueb)
a)
Compound
n
1
2
3
4
5
6
7
8
9
1
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
o-CH3
o-OCH3
o-CH3
o-OCH3
o-CH3
o-OCH3
p-CH3
p-OCH3
p-CH3
p-OCH3
p-CH3
p-OCH3
o-CH3
o-OCH3
o-CH3
o-OCH3
o-CH3
o-OCH3
p-CH3
p-OCH3
p-CH3
p-OCH3
p-CH3
8.568 0.102
8.376 0.097
8.331 0.110
8.193 0.091
8.865 0.102
9.365 0.142
6.531 0.085
6.243 0.112
8.532 0.108
7.350 0.162
7.643 0.112
7.766 0.099
8.101 0.115
8.005 0.107
8.075 0.127
8.376 0.080
8.102 0.087
8.041 0.092
7.747 0.094
7.416 0.116
7.651 0.091
7.581 0.121
7.831 0.104
7.556 0.131
9.323 0.130
9.41
8.88
8.93
8.57
10.39
10.09
3.15
2.95
3.52
0.62
1.04
5.31
8.45
7.98
7.30
9.66
8.12
5.76
3.61
1.21
1.96
1.61
2.22
0.96
1
2
2
3
3
1
1
2
2
3
3
1
1
2
2
3
3
1
1
2
2
3
3
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Prazosin
Ph
Ph
Ph
p-OCH3
a) Values are means standard derivation of three repeated experiments. b) Fit value indicates how well the features in the pharmacophore overlap the chemical features in
the molecule.
Fig. 2. The Relationships between Fit Values and Antagonistic Activities for Compounds 1–24, Expressed as pA2 Values
Diamond and triangle represent the compounds (1–6, 13–18) with ortho substituents on the phenyl ring and compounds (7–12, 19–24) with para substituents on the
phenyl ring, respectively.
the influences on antagonistic activity. Unfortunately, no clear pharmacological activities and to demonstrate whether the
trend was observed in present work. For the 4-methylcouma- 7-mercaptocoumarin with a hydrophobic group at position
rin series, the ortho-substituted derivatives 1–6 with 4 and 2 4 could fulfill the HBA and HY features of pharmacophore
carbon atoms linker seemed to be beneficial for the activity, model, the pharmacophore model of the ideal α1-AR an-
but the opposite trend was found for para-substituted deriva- tagonists has been generated according to previous methods
tives 7–12, compound 9 with 3 carbon atoms linker exhibited reported by Barbaro et al.7) The fit values, listed in Table 1,
a higher activity. In 4-phenylcoumarin series, lengthening of were used to indicate how well the features in the pharmaco-
the alkyl spacer from an ethyl to a butyl chain only produced phore overlap the chemical features of present compounds. A
a slight variation of antagonistic activities. For example, range linear regression analysis performed to explore the relation-
of pA2 values of compounds 13–18 only varied from 8.005 to ships between the antagonistic activities and fit values was
8.376 with lengthening of the alkyl spacer.
graphically shown in Fig. 2. The regression line exhibited
Molecular Modeling With the aim to rationalize a correlation coefficient r of 0.71. This result suggested that
the relationships between their structural features and most of the compounds exhibiting high antagonistic activity

January 2013
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Fig. 3. Mappings of the Compounds 6 (a), 5 (b), 12 (c) and 18 (d) with the Features of Pharmacophore Model
Features: hydrogen-bond acceptor (HBA), hydrophobic regions (HY1-3) and positive ionizable feature (PI).
for α1-ARs would therefore be expected to perfectly match the the mapping of the compound 12 showed the PI, HY2 and
features of pharmacophore model.
HY3 could be nicely mapped by the piperazinyl N-1 atom,
Inspection of Table 1 and Fig. 2 indicated that the activ- methoxy group on the phenyl ring and methyl group at 4-posi-
ity of compound 6 seemed to be higher than the prediction tion of coumarin moiety, respectively. However, the HY1 was
computed from pharmacophore model. It’s probably because completely omitted. Unexpectedly, the coumarin carbonyl
that compound 6 was more selective for the α1A-AR, which a moiety was the hydrogen bond acceptor group instead of
predominant subtype of α1-ARs in rat anococcygeus smooth sulfur atom from 7-mercaptocoumarin moiety (Fig. 3c). This
muscle.42–44) Therefore, the fit value generated by present translation caused by the absence of the phenyl ring into the
general α1-AR pharmacophore model was not well correlated HY2 feature, further decreased the antagonistic activity.
to its antagonistic activity. However, despite such an error
The pharmacophore model was also able to account for the
between its activity and fit value existed, compound 6 as the decreased activity of 4-phenylcouamrin derivatives. In fact,
most potent compound still showed nice fitting to the phar- the introduction of the large hydrophobic group, phenyl group,
macophore model. As showed in Fig. 3a, all features of phar- let them partially match the features of pharmacophore model.
macophore model were nicely mapped with the corresponding As an example, compound 18 (fit value=5.76) exhibited a far
chemical functional groups of compound 6. The pharmaco- lower fit value than that of its methyl analogue 6 (fit value=
phore mapping of 6 showed that the HY2 and HY1 features 10.09). The pharmacophore mapping of 18 showed (Fig. 3d)
were filled by the ortho-methoxy substituent and the phenyl that the PI desired for the antagonistic activity was only par-
ring, respectively, while the piperazine nitrogen atom directly tially filled by the N-1 atom of piperazine. This partial fit may
linked to the alkyl spacer, corresponded to the positive ioniz- lead to a decrease of α1-AR antagonistic activity.
able feature (PI) of the pharmacophore. The sulfur atom from
7-mercaptocoumarin moiety overlapped HBA, while methyl
group at the 4-position of coumarin moiety mapped to HY3.
Conclusion
In conclusion, a series of novel 7-mercaptocoumarin deriva-
The compound 5 which exhibited antagonistic activity slightly tives has been designed, synthesized and evaluated for their
lower than that of compound 6 also showed nice fitting to the α1-AR antagonistic activities by functional bioassay. Most of
pharmacophore model. As showed in Fig. 3b, the orientation them exhibited strong α1-AR antagonistic activities. Especially
of 5 into the pharmacophore model was similar to that of 6, compound 6 with an ortho-methoxy group at the phenyl ring
the only difference was that the HY2 feature filled by methyl of phenylpiperazine linked to 7-mercaptocoumarin moiety
group instead of methoxy group. Taken together, the above by a four carbon spacer, gave the most potent activity with
results confirmed our hypothesis that 7-mercaptocouamrin de- the pA2 value of 9.365. Structure–activity relationship stud-
rivatives containing various substituted phenylpiperazine moi- ies revealed that small hydrophobic group at the terminal
eties could meet the requirements of pharmacophore model heterocyclic ring and ortho substituents on the phenyl ring of
and exhibit α1-AR antagonistic properties.
phenylpiperazine moiety were the essential structural factors
The activity data showed that the ortho substituents on for α1-adrenoceptor antagonistic activity. The pharmacophore
phenyl ring of phenylpiperazine moiety were more beneficial modeling studies further confirmed their structure–activity
for the antagonistic activity than para substituents. The pres- relationship and also demonstrated that 7-mercaptocoumarin
ent modeling results may give rational explanations for this moiety could be a useful scaffold for design of α1-AR antago-
phenomenon. From Fig. 2, it could be clearly seen that the nists.
fit values of compounds 1–6 and 13–18 (diamond) were also
better than those of compounds 7–12 and 19–24 (triangle). Su-
Experimental
perposition of such compounds into the pharmacophore model
Chemistry All chemicals (reagent grade) used were pur-
showed the presence of para-substituted phenyl ring led to a chased from Sinopharm Chemical Reagent Co., Ltd. (China).
partial fit to the HY1–HY2 system in the model. For example, Reaction progress was monitored using analytical thin layer

20
Vol. 61, No. 1
chromatography (TLC) on precoated silica gel GF254 (Qing- ESI-MS m/z: 326.0 [M+H]+.
dao Haiyang Chemical Plant, Qingdao, China) plates and
S-(4-Methyl-2-oxo-2H-chromen-7-yl)dimethylcarbamo-
the spots were detected under UV light (254nm). Elemental thioate (28a) Compound 27a (2.0g, 7.60mmol) was heated
analyses were performed with an Elementar Vario EL III to 220–230°C for 1h. The crude product was recrystallized
analyzer and the results were within 0.4% of theoretical from EtOH to give 28a as a yellow solid, yield 82%. mp
values. Melting point was measured on an XT-4 micromelt- 161–162°C. IR (KBr) cm−1: 3070, 2955, 1725, 1673, 1599, 1383,
1
ing point instrument and uncorrected. IR (KBr-disc) spectra 1360, 1060, 898, 876, 861. H-NMR (CDCl3) δ: 2.43 (3H, s),
1
were recorded by Bruker Tensor 27 spectrometer. H-NMR 3.08 (3H, m), 3.12 (3H, m), 6.32 (1H, s), 7.45 (1H, dd, J=8.0,
spectra were measured on a Bruker ACF-500 spectrometer 1.5Hz), 7.50 (1H, d, J=1.5Hz), 7.60 (1H, d, J=8.0Hz). ESI-MS
at 25°C and referenced to tetramethylsilane (TMS). Chemi- m/z: 264.1 [M+H]+.
cal shifts are reported in ppm (δ) using the residual solvent
S-(2-Oxo-4-phenyl-2H-chromen-7-yl)dimethylcarbamo-
line as internal standard. Splitting patterns are designed as s, thioate (28b) According to the procedure already described
singlet; d, doublet; t, triplet; m, multiplet. Mass spectra were for 28a, 28b (2.0g, 6.15mmol) was heated to give the 28b
obtained on a MS Agilent 1100 Series LC/MSD Trap mass as yellow solid, yield 79%. mp 155–156°C. IR (KBr) cm−1:
spectrometer (electrospray ionization (ESI)-MS) and a Mari- 3058, 2934, 1733, 1676, 1600, 1370, 1246, 1062, 968, 879, 819.
ner ESI-TOF spectrometer (high resolution (HR)-ESI-MS), 1H-NMR (CDCl3) δ: 3.30 (3H, m), 3.42 (3H, m), 6.29 (1H, s),
respectively. Column chromatography was performed on silica 6.70 (1H, dd, J=8.5, 2.5Hz), 6.89 (1H, d, J=2.5Hz), 7.36 (1H,
gel (90-150µm; Qingdao Marine Chemical Inc.).
d, J=8.5Hz), 7.45 (2H, m), 7.53 (3H, m). ESI-MS m/z: 326.1
7-Hydroxy-4-methyl-2H-chromen-2-one (26a) To an [M+H]+.
ice-cold solution of resorcinol (5.5g, 0.05mol) in dioxane,
7-Mercapto-4-methyl-2H-chromen-2-one (29a) Under
conc. H2SO4 (2mL) was added dorpwise under 25°C. After nitrogen, compound 28a (1.2g, 4.56mmol) and potassium hy-
the addition of concentrated sulphuric acid, ethylacetoacetate droxide (1.0g, 18.20mmol) were dissolved in MeOH (150mL).
(7mL) was added and the mixture was heated to 60°C for The mixture was refluxed for 1.5h with stirring. After cooling
4h. Then, the mixture was poured into cold water and the to room temperature, the mixture was acidified with concen-
precipitate was filtered and dried under reduced pressure. The trated HCl, and MeOH was removed under vacuum. Then
resulting mixture was recrystallized from methanol to give ice water (100mL) was added, and the reaction mixture was
26a as white needle crystals, yield 92%. mp 186–187°C. IR filtered. The precipitate was recrystallized from MeOH to
(KBr) cm−1: 3495, 3119, 1660, 1600, 1454, 1390, 1274, 938, afford 29a as a yellow solid, yield 75%. mp 139–140°C. IR
1
848. H-NMR (acetone-d6) δ: 2.40 (3H, s) 6.09 (1H, s), 6.75 (KBr) cm−1: 3016, 2506, 1720, 1601, 1542, 1385, 1253, 1102,
1
(1H, d, J=2.5Hz), 6.85 (1H, dd, J=9.0, 2.5Hz,), 7.61 (1H, d, 874, 806. H-NMR (CDCl3) δ: 2.40 (3H, s), 6.28 (1H, s), 7.19
J=9.0Hz). ESI-MS m/z: 175.0 [M−H]− .
(1H, dd, J=8.0, 1.5Hz), 7.23 (1H, d, J=1.5Hz), 7.50 (1H, d,
7-Hydroxy-4-phenyl-2H-chromen-2-one (26b) Accord- J=8.0Hz). ESI-MS m/z: 190.8 [M−H]−.
ing to the procedure already described for 26a, 26b was
7-Mercapto-4-phenyl-2H-chromen-2-one (29b) Accord-
obtained as yellow plate crystals by reacting resorcinol (5.5g, ing to the procedure already described for 29a, 29b was ob-
0.05mol) with ethylbenzoylacetate (10mL), yield 90%. mp tained as a yellow solid by reacting 28b with KOH, yield 72%.
249–251°C. IR (KBr) cm−1: 3102, 1692, 1598, 1377, 1110, mp 150–152°C. IR (KBr) cm−1: 3063, 2514, 1714, 1602, 1534,
1
1
1000, 863, 860, 773. H-NMR (CDCl3) δ: 6.30 (1H, s), 7.10 1372, 1245, 1084, 937, 876, 766. H-NMR (CDCl3) δ: 6.22 (1H,
(1H, dd, J=8.5, 2.5Hz), 7.23 (1H, d, J=2.5Hz), 7.32 (1H, d, s), 6.75 (1H, dd, J=8.5, 2.5Hz), 6.90 (1H, d, J=2.5Hz), 7.39
J=8.5Hz), 7.55–7.48 (5H, m). ESI-MS m/z: 236.9 [M−H]−.
(1H, d, J=8.5Hz), 7.45 (2H, m), 7.52 (3H, m). ESI-MS m/z:
O-(4-Methyl-2-oxo-2H-chromen-7-yl)dimethylcarbamo- 253.0 [M−H]−.
thioate (27a) Under nitrogen, 26a (2.0g, 11.35mmol) was General Procedure for the Preparation of 30a–f
A
acylated with N,N-dimethylcarbamothioic chloride (2.8g, mixture of 29 (5mmol) with suitable α,ω-dibromoalkanes
22.71mmol) in anhydrous CH2Cl2 in presence of DMAP (50mmol) and dry K2CO3 in 15mL of acetone was refluxed
(5.5g, 45.40mmol) for 96h at room temperature. After re- under stirring for 4h. The filtered residue was evaporated
moval of the solvent under reduced pressure, the residue was under reduced pressure and purified by chromatography on a
washed with water and dried to give a white solid. The 27a silica gel column with hexane/acetone (20:1) to give the pure
was obtained in yield 84% as white cluster crystals after re- products as white solid.
crystallization from ethyl acetate. mp 208–209°C. IR (KBr)
7-((2-Bromoethyl)thio)-4-methyl-2H-chromen-2-one (30a):
cm−1: 3056, 2929, 1721, 1600, 1542, 1377, 1243, 1130, 937, 856, Yield 70%. mp 90–92°C. IR (KBr) cm−1: 3071, 2973, 2839,
1
816. H-NMR (CDCl3) δ: 2.40 (3H, s), 3.30 (3H, s), 3.42 (3H, 1718, 1600, 1544, 1388, 1241, 1157, 1055, 926, 845, 817.
s), 6.30 (1H, s), 6.75 (1H, d, J=2.5Hz), 6.85 (1H, dd, J=8.5, 1H-NMR (CDCl3) δ: 2.42 (3H, s), 3.42 (2H, m), 3.52 (2H,
2.5Hz), 7.60 (1H, d, J=8.5Hz). ESI-MS m/z: 264.0 [M+H]+.
m), 6.25 (1H, s), 7.22 (1H, dd, J=8.5, 2.0Hz), 7.25 (1H, d,
O-(2-Oxo-4-phenyl-2H-chromen-7-yl)dimethylcarbamo- J=2.0Hz), 7.52 (1H, d, J=8.5Hz). ESI-MS m/z: 299.1 [M+H]+.
thioate (27b) According to the procedure already described
7-((3-Bromopropyl)thio)-4-methyl-2H-chromen-2-one (30b):
for 27a, the 27b was obtained as white needle crystals by re- Yield 65%. mp 87–88°C. IR (KBr) cm−1: 3065, 2966, 2860,
acting 26b (3.0g, 12.59mol) with N,N-dimethylcarbamothioic 1714, 1598, 1388, 1240, 1163, 1053, 1008, 965, 853, 816.
chloride (3.1g, 25.08mmol), yield 83%. mp 180–182°C. IR 1H-NMR (CDCl3) δ: 2.23 (2H, m), 2.41 (3H, s), 3.19 (2H, t,
(KBr) cm−1: 3066, 2937, 1729, 1613, 1545, 1375, 1254, 1107, J=9.0Hz), 3.53 (2H, t, J=6.0Hz), 6.23 (1H, s), 7.19 (1H, dd,
1
998, 938, 866, 769. H-NMR (CDCl3) δ: 3.29 (3H, s), 3.40 J=8.0, 1.5Hz), 7.21 (1H, d, J=1.5Hz), 7.49 (1H, d, J=8.0Hz).
(3H, s), 6.31 (1H, s), 7.12 (1H, dd, J=8.0, 2.0Hz), 7.28 (1H, d, ESI-MS m/z: 313.2 [M+H]+.
J=2.0Hz), 7.36 (1H, d, J=8.0Hz), 7.45 (2H, m), 7.53 (3H, m).
7-((4-Bromobutyl)thio)-4-methyl-2H-chromen-2-one (30c):

January 2013
21
1
Yield 62%. mp 71–73°C. IR (KBr) cm−1: 3065, 2952, 2855, 1383, 1364, 1224, 1168, 1049, 1010, 958, 869, 768. H-NMR
1716, 1597, 1386, 1242, 1164, 1052, 1010, 956, 873, 841. (CDCl3) δ: 1.95 (2H, brs), 2.31 (3H, s), 2.41 (3H, s), 2.50–2.70
1H-NMR (CDCl3) δ: 1.92 (2H, m), 2.07 (2H, m), 2.39 (3H, s), (6H, m), 2.90 (4H, brs), 3.10 (2H, t, J=7.0Hz), 6.22 (1H, s),
3.08 (2H, t, J=9.0Hz), 3.46 (2H, t, J=9.0Hz), 6.22 (1H, s), 6.99–6.96 (1H, m), 7.05 (1H, d, J=7.5Hz), 7.15–7.18 (2H, m),
7.21 (1H, dd, J=8.0, 2.0Hz), 7.22 (1H, d, J=2.0Hz), 7.50 (1H, 7.19 (1H, dd, J=8.0, 2.0Hz), 7.22 (1H, d, J=2.0Hz), 7.46 (1H,
d, J=8.0Hz). ESI-MS m/z: 327.2 [M+H]+.
d, J=8.0Hz). ESI-MS m/z: 409.2 [M+H]+. HR-MS: Calcd for
7-((2-Bromoethyl)thio)-4-phenyl-2H-chromen-2-one (30d): C24H29N2O2S [M+H]+ 409.1944, Found 409.1952. Anal. Calcd
Yield 63%. mp 119–120°C. IR (KBr) cm−1: 3063, 2967, for C24H28N2O2S: C, 70.55; H, 6.91; N, 6.86; S, 7.85. Found: C,
2847, 1711, 1600, 1375, 1241, 1148, 1074, 1001, 851, 830, 767. 70.35; H, 7.05; N, 6.91; S, 7.81.
1H-NMR (CDCl3) δ: 3.50 (2H, m), 3.55 (2H, m), 6.32 (1H, s),
7-((3-(4-(2-Methoxyphenyl)piperazin-1-yl)propyl)thio)-4-
7.10 (1H, dd, J=8.5, 1.5Hz), 7.29 (1H, d, J=2.0Hz), 7.37 (1H, methyl-2H-chromen-2-one (4): Yield 21%. Pale yellow solid.
d, J=8.5Hz), 7.41–7.43 (2H, m), 7.51–7.53 (3H, m). ESI-MS mp 94–95°C. IR (KBr) cm−1: 3020, 2939, 2858, 2811, 1712,
m/z: 361.0 [M+H]+.
1601, 1492, 1389, 1372, 1225, 1129, 1054, 1012, 968, 839, 762.
7-((3-Bromopropyl)thio)-4-phenyl-2H-chromen-2-one (30e): 1H-NMR (CDCl3) δ: 1.93–1.96 (2H, m), 2.42 (3H, s), 2.64–2.78
Yield 61%. mp 106–107°C. IR (KBr) cm−1: 3065, 2973, 2871, (6H, m), 3.02–3.20 (6H, m), 3.82 (3H, s), 6.22 (1H, s), 6.85
1709, 1596, 1379, 1238, 1159, 1079, 977, 859, 768. H-NMR (1H, d, J=8.5Hz), 6.90–7.01 (3H, m), 7.19 (1H, dd, J=8.0,
1
(CDCl3) δ: 2.20 (m, 2H), 3.18 (2H, t, J=9.0Hz), 3.52 (2H, 1.5Hz), 7.21 (1H, d, J=1.5Hz), 7.46 (1H, d, J=8.0Hz). ESI-MS
t, J=6.0Hz), 6.30 (1H, s), 7.09 (1H, dd, J=8.0, 1.5Hz), 7.23 m/z: 425.2 [M+H]+. HR-MS: Calcd for C24H29N2O3S [M+H]+
(1H, d, J=2.0Hz), 7.35 (1H, d, J=8.5Hz), 7.38–7.43 (2H, 425.1893, Found 425.1897. Anal. Calcd for C24H28N2O3S: C,
m),7.49–7.53 (3H, m). ESI-MS m/z: 375.2 [M+H]+.
67.90; H, 6.65; N, 6.60; S, 7.55. Found: C, 67.72; H, 6.53; N,
7-((4-Bromobutyl)thio)-4-phenyl-2H-chromen-2-one (30f): 6.85; S, 7.58.
Yield 65%. mp 98–100°C. IR (KBr) cm−1: 3062, 2976, 2854,
4-Methyl-7-((4-(4-(o-tolyl)piperazin-1-yl)butyl)thio)-2H-
1
1710, 1598, 1241, 1147, 1075, 976, 873, 765. H-NMR (CDCl3) chromen-2-one (5): Yield 22%. Pale yellow solid. mp
δ: 1.90 (2H, m), 2.05 (2H, m), 3.05 (2H, t, J=9.0Hz), 3.45 (2H, 89–90°C. IR (KBr) cm−1: 3020, 2939, 2858, 2811, 1712, 1601,
t, J=9.0Hz), 6.31 (1H, s), 7.10 (1H, dd, J=8.5, 2.0Hz), 7.25 1492, 1389, 1372, 1225, 1129, 1054, 1012, 968, 839, 762.
(1H, d, J=2.0Hz), 7.36 (1H, d, J=8.5Hz), 7.40–7.45 (2H, m), 1H-NMR (CDCl3) δ: 1.85–1.76 (4H, m), 2.35 (3H, s), 2.41 (3H,
7.50–7.55 (3H, m). ESI-MS m/z: 389.0 [M+H]+.
s), 2.52 (2H, brs), 2.75 (4H, brs), 3.02–3.15 (6H, m), 6.22 (1H,
s), 6.98–6.99 (1H, m), 7.05 (1H, d, J=7.5Hz), 7.15–7.16 (2H,
General Procedure for the Preparation of 1–24
A
mixture of 30 (2.34mmol), the appropriate arlylpiperazine m), 7.17 (1H, dd, J=8.0, 2.0Hz), 7.18 (1H, d, J=2.0Hz), 7.46
(2.57mmol), anhydrous K2CO3 (2.57mmol) in dry acetonitrile (1H, d, J=8.0Hz). ESI-MS m/z: 423.2 [M+H]+. HR-MS: Calcd
was refluxed for 8h. The mixture was filtered and the filtrate for C25H31N2O2S [M+H]+ 423.2101, Found 423.2106. Anal.
was evaporated. The obtained residue was purified by chroma- Calcd for C25H30N2O2S: C, 71.06; H, 7.16; N, 6.63; S, 7.59.
tography on a silica gel column with petroleum ether–acetone Found: C, 70.89; H, 7.20; N, 6.71; S, 7.39.
(2:1 or 1:1) to give 1–24.
7-((4-(4-(2-Methoxyphenyl)piperazin-1-yl)butyl)thio)-4-
4-Methyl-7-((2-(4-(o-tolyl)piperazin-1-yl)ethyl)thio)-2H- methyl-2H-chromen-2-one (6): Yield 42%. Pale yellow solid.
chromen-2-one (1): Yield 22%. Pale yellow solid. mp 79–80°C. mp 75–76°C IR (KBr) cm−1: 3032, 2936, 2872, 2816, 1718,
IR (KBr) cm−1: 3024, 2940, 2879, 1713, 1602, 1491, 1445, 1498, 1458, 1389, 1370, 1236, 1125, 1053, 954, 847, 752.
1
1388, 1370, 1224, 1125, 1063, 1007, 965, 838, 766. H-NMR 1H-NMR (CDCl3) δ: 1.75 (4H, brs), 2.42 (3H, s), 2.55 (2H,
(CDCl3) δ: 2.25 (3H, s), 2.45 (3H, s), 2.74 (4H, brs), 2.82–2.83 brs), 2.72 (4H, brs), 3.03–3.06 (2H, m), 3.15 (4H, brs), 3.85
(2H, m), 2.99–3.02 (4H, m), 3.23–3.25 (2H, m), 6.21 (1H, s), (3H, s), 6.22 (1H, s), 6.85–7.08 (4H, m), 7.16 (1H, dd, J=8.0,
6.99–7.01 (1H, m), 7.04 (1H, d, J=8.0Hz), 7.18–7.15 (2H, m), 2.0Hz), 7.18 (1H, d, J=2.0Hz), 7.46 (1H, d, J=8.0Hz). ESI-MS
7.22 (1H, dd, J=9.0, 1.5Hz), 7.23 (1H, d, J=1.5Hz), 7.49 (1H, m/z: 439.2 [M+H]+. HR-MS: Calcd for C25H31N2O3S [M+H]+
d, J=9.0Hz). ESI-MS m/z: 395.2 [M+H]+. HR-MS: Calcd for 439.2050, Found 439.2052. Anal. Calcd for C25H30N2O3S: C,
C23H27N2O2S [M+H]+ 395.1788, Found 395.1791. Anal. Calcd 68.46; H, 6.89; N, 6.39; S, 7.31. Found: C, 68.53; H, 6.90; N,
for C23H26N2O2S: C, 70.02; H, 6.64; N, 7.10; S, 8.13. Found: C, 6.35; S, 7.29.
69.93; H, 6.71; N, 7.21; S, 8.10.
4-Methyl-7-((2-(4-(p-tolyl)piperazin-1-yl)ethyl)thio)-2H-
7-((2-(4-(2-Methoxyphenyl)piperazin-1-yl)ethyl)thio)-4- chromen-2-one (7): Yield 21%. White cluster crystals. mp
methyl-2H-chromen-2-one (2): Yield 22%. White solid. mp 118–120°C. IR (KBr) cm−1: 3029, 2943, 2878, 2808, 1723,
94–95°C. IR (KBr) cm−1: 3046, 2941, 2878, 1717, 1603, 1602, 1442, 1387, 1366, 1222, 1141, 1052, 1005, 955, 836, 811.
1497, 1449, 1385, 1241, 1122, 1054, 1008, 954, 854, 807, 1H-NMR (CDCl3) δ: 2.30 (3H, s), 2.45 (3H, s), 2.66–2.75 (4H,
753. 1H-NMR (CDCl3) δ: 2.45 (3H, s), 2.82–2.77 (6H, m), m), 2.82 (2H, t, J=7.0Hz), 3.21–3.37 (6H, m), 6.21 (1H, s), 6.90
3.10–3.22 (6H, m), 3.85 (3H, s), 6.21 (1H, s), 6.86 (1H, dd, (2H, d, J=8.0Hz), 7.14 (2H, d, J=8.0Hz), 7.22 (1H, dd, J=8.0,
J=8.0Hz, 1.5Hz), 6.92–6.96 (2H, m), 6.99–7.03 (1H, m), 7.21 1.5Hz), 7.24 (1H, d, J=1.5Hz), 7.52 (1H, d, J=8.0Hz). ESI-MS
(1H, dd, J=8.0, 1.5Hz), 7.22 (1H, d, J=1.5Hz), 7.48 (1H, d, m/z: 395.2 [M+H]+. HR-MS: Calcd for C23H27N2O2S [M+H]+
J=8.0Hz). ESI-MS m/z: 411.2 [M+H]+. HR-MS: Calcd for 395.1788, Found 395.1790. Anal. Calcd for C23H26N2O2S: C,
C23H27N2O3S [M+H]+ 411.1737, Found 411.1739. Anal. Calcd 70.02; H, 6.64; N, 7.10; S, 8.13. Found: C, 70.05; H, 6.82; N,
for C23H26N2O3S: C, 67.29; H, 6.38; N, 6.82; S, 7.81. Found: C, 7.13; S, 7.95.
67.50; H, 6.40; N, 6.71; S, 7.72.
7-((2-(4-(4-Methoxyphenyl)piperazin-1-yl)ethyl)thio)-4-
4-Methyl-7-((3-(4-(o-tolyl)piperazin-1-yl)propyl)thio)-2H- methyl-2H-chromen-2-one (8): Yield 22%. White cluster crys-
chromen-2-one (3): Yield 20%. Pale yellow solid. mp 87–89°C. tals. mp 125–126°C. IR (KBr) cm−1: 3048, 2940, 2880, 2813,
IR (KBr) cm−1: 3048, 2975, 2875, 2812, 1718, 1603, 1492, 1713, 1602, 1445, 1388, 1223, 1125, 1052, 1007, 955, 838, 766.

22
Vol. 61, No. 1
1H-NMR (CDCl3) δ: 2.41 (3H, s), 2.70 (4H, brs), 2.78 (2H, t, 6.29 (1H, s), 6.97–6.99 (1H, m), 7.04 (1H, d, J=7.5Hz),
J=7.0Hz), 3.11–3.13 (4H, m), 3.19 (2H, t, J=6.5Hz), 3.79 (3H, 7.14 (1H, dd, J=8.5, 1.5Hz), 7.15–7.18 (2H, m), 7.26 (1H, d,
s), 6.21 (1H, s), 6.84 (2H, d, J=9.0Hz), 6.91 (2H, d, J=9.0Hz), J=2.0Hz), 7.39 (1H, d, J=8.5Hz), 7.46–7.43 (2H, m), 7.53–7.51
7.20 (1H, dd, J=8.0, 2.0Hz), 7.22 (1H, d, J=2.0Hz), 7.46 (1H, (3H, m). ESI-MS m/z: 457.2 [M+H]+. HR-MS: Calcd for
d, J=8.0Hz). ESI-MS m/z: 411.2 [M+H]+. HR-MS: Calcd for C28H29N2O2S [M+H]+ 457.1944, Found 457.1949. Anal. Calcd
C23H27N2O3S [M+H]+ 411.1737, Found 411.1742. Anal. Calcd for C28H28N2O2S: C, 73.65; H, 6.18; N, 6.14; S, 7.02. Found: C,
for C23H26N2O3S: C, 67.29; H, 6.38; N, 6.82; S, 7.81. Found: C, 73.70; H, 6.25; N, 6.09; S, 7.13.
67.32; H, 6.51; N, 6.79; S, 7.65.
7-((2-(4-(2-Methoxyphenyl)piperazin-1-yl)ethyl)thio)-4-
4-Methyl-7-((3-(4-(p-tolyl)piperazin-1-yl)propyl)thio)-2H- phenyl-2H-chromen-2-one (14): Yield 18%. Yellow oil.
chromen-2-one (9): Yield 17%. Colorless plate crystals. mp IR (KBr) cm−1: 3060, 2938, 2815, 1733, 1597, 1446, 1372,
1
136–137°C. IR (KBr) cm−1: 3039, 2945, 2877, 2812, 1724, 1309, 1240, 1130, 1006, 967, 853, 767. H-NMR (CDCl3) δ:
1601, 1440, 1382, 1314, 1239, 1132, 1052, 1007, 956, 871, 810. 2.65–2.80 (6H, m), 3.05–3.20 (6H, m), 3.81 (3H, s), 6.24 (1H,
1H-NMR (CDCl3) δ: 1.95–1.85 (2H, m), 2.26 (3H, s), 2.42 (3H, s), 6.88–7.08 (4H, m), 7.15 (1H, dd, J=8.5, 2.0Hz), 7.29 (1H, d,
s), 2.55 (2H, t, J=6.0Hz), 2.64 (4H, m), 3.05–3.16 (6H, m), J=2.0Hz), 7.39 (1H, d, J=8.5Hz), 7.45–7.42 (2H, m), 7.51–7.53
6.22 (1H, s), 6.85 (2H, d, J=7.0Hz), 6.92 (2H, d, J=7.0Hz), (3H, m). ESI-MS m/z: 473.2 [M+H]+. HR-MS: Calcd for
7.18 (1H, dd, J=8.0, 1.5Hz), 7.22 (1H, d, J=1.5Hz), 7.46 (1H, C28H29N2O3S [M+H]+ 473.1893, Found 473.1896. Anal. Calcd
d, J=8.5Hz). ESI-MS m/z: 409.2 [M+H]+. HR-MS: Calcd for for C28H28N2O3S: C, 71.16; H, 5.97; N, 5.93; S, 6.78. Found: C,
C24H29N2O2S [M+H]+ 409.1944, Found 409.1950. Anal. Calcd 71.12; H, 6.04; N, 6.12; S, 6.69.
for C24H28N2O2S: C, 70.55; H, 6.91; N, 6.86; S, 7.85. Found: C,
70.45; H, 7.01 ; N, 6.82 ; S, 7.91.
4-Phenyl-7-((3-(4-(o-tolyl)piperazin-1-yl)propyl)thio)-2H-
chromen-2-one (15): Yield 34%. Pale yellow solid. mp
7-((3-(4-(4-Methoxyphenyl)piperazin-1-yl)propyl)thio)-4- 103–104°C. IR (KBr) cm−1: 3034, 2965, 2936, 2822, 1709,
methyl-2H-chromen-2-one (10): Yield 23%. Colorless plate 1599, 1444, 1372, 1311, 1231, 1128, 1075, 1026, 967, 863, 763.
crystals. mp 140–141°C. IR (KBr) cm−1: 3045, 2994, 2946, 1H-NMR (CDCl3) δ: 1.90–2.00 (2H, m), 2.30 (3H, s), 2.55
2880, 2812, 1724, 1600, 1437, 1382, 1237, 1131, 1036, 1009, (2H, t, J=7.0Hz), 2.65 (4H, brs), 3.02 (4H, brs), 3.11 (2H,
1
956, 877, 814, 801. H-NMR (CDCl3) δ: 1.91–1.95 (2H, m), t, J=7.0Hz), 6.29 (1H, s), 6.96–7.00 (1H, m), 7.04 (1H, d,
2.42 (3H, s), 2.64–2.78 (6H, m), 3.02–3.20 (6H, m), 3.82 (3H, J=7.5Hz), 7.12 (1H, dd, J=8.5, 1.5Hz), 7.15–7.18 (2H, m), 7.26
s), 6.22 (1H, s), 6.85 (2H, d, J=7.0Hz), 6.92 (2H, d, J=7.0Hz), (1H, d, J=2.0Hz), 7.39 (1H, d, J=8.5Hz), 7.46–7.42 (2H, m),
7.19 (1H, dd, J=8.5, 1.5Hz), 7.21 (1H, d, J=1.5Hz), 7.46 (1H, 7.54–7.51 (3H, m). ESI-MS m/z: 471.2 [M+H]+. HR-MS: Calcd
d, J=8.5Hz). ESI-MS m/z: 425.2 [M+H]+. HR-MS: Calcd for for C29H31N2O2S [M+H]+ 471.2102, Found 471.2101. Anal.
C24H29N2O3S [M+H]+ 425.1893, Found 425.1898. Anal. Calcd Calcd for C29H30N2O2S: C, 74.01; H, 6.43; N, 5.95; S, 6.81.
for C24H28N2O3S: C, 67.90; H, 6.65; N, 6.60; S, 7.55. Found: C, Found: C, 74.06; H, 6.67; N, 5.84; S, 6.79.
67.82; H, 6.91; N, 6.61; S, 7.43.
7-((3-(4-(2-Methoxyphenyl)piperazin-1-yl)propyl)thio)-4-
4-Methyl-7-((4-(4-(p-tolyl)piperazin-1-yl)butyl)thio)-2H- phenyl-2H-chromen-2-one (16): Yield 29%. Pale yellow solid.
chromen-2-one (11): Yield 22%. White solid. mp 107–108°C mp 85–86°C. IR (KBr) cm−1: 3060, 2939, 2876, 1708, 1596,
1
IR (KBr) cm−1: 3032, 2960, 2935, 2864, 2808, 1711, 1598, 1498, 1374, 1241, 1074, 1026, 1008, 968, 853, 767. H-NMR
1445, 1370, 1249, 1162, 1126, 1052, 1042, 966, 847, 808. (CDCl3) δ: 1.95–2.04 (2H, m), 2.64–2.78 (6H, m), 3.02–3.20
1H-NMR (CDCl3) δ: 1.72–1.80 (4H, m), 2.25 (3H, s), 2.42 (6H, m), 3.82 (3H, s), 6.24 (1H, s), 6.88 (1H, d, J=8.0Hz),
(3H, s), 2.45–2.47 (2H, m), 2.62 (4H, brs), 3.02–3.05 (2H, m), 6.91–7.04 (3H, m), 7.15 (1H, dd, J=8.5, 1.5Hz), 7.29 (1H, d,
3.15–3.18 (4H, m), 6.22 (1H, s), 6.85 (2H, d, J=8.5Hz), 7.08 J=2.0Hz), 7.39 (1H, d, J=8.5Hz), 7.45–7.43 (2H, m),7.53–7.51
(2H, d, J=8.5Hz), 7.15(1H, dd, J=8.0, 1.5Hz), 7.17 (1H, d, (3H, m). ESI-MS m/z: 487.2 [M+H]+. HR-MS: Calcd for
J=1.5Hz), 7.46 (1H, d, J=8.0Hz). ESI-MS m/z: 423.2 [M+H]+. C29H31N2O3S [M+H]+ 487.2050, Found 487.2056. Anal. Calcd
HR-MS: Calcd for C25H31N2O2S [M+H]+ 423.2101, Found for C29H30N2O3S: C, 71.58; H, 6.21; N, 5.76; S, 6.59. Found: C,
423.2104. Anal. Calcd for C25H30N2O2S: C, 71.06; H, 7.16; N, 71.37; H, 6.18; N, 5.85; S, 6.52.
6.63; S, 7.59. Found: C, 71.11; H, 7.25; N, 6.64; S, 7.55.
4-Phenyl-7-((4-(4-(o-tolyl)piperazin-1-yl)butyl)thio)-2H-
7-((4-(4-(4-Methoxyphenyl)piperazin-1-yl)butyl)thio)-4- chromen-2-one (17): Yield 21%. White solid. mp 88–90°C. IR
methyl-2H-chromen-2-one (12): Yield 24%. White solid. mp (KBr) cm−1: 3063, 2997, 2938, 2811, 1712, 1601, 1444, 1372,
1
119–120°C IR (KBr) cm−1: 3029, 2988, 2840, 2808, 1713, 1601, 1225, 1129, 1054, 1012, 968, 839, 762. H-NMR (CDCl3) δ:
1
1384, 1228, 1030, 1013, 956, 861, 820, 748. H-NMR (CDCl3) 1.74–1.80 (4H, m), 2.31 (3H, s), 2.50 (2H, t, J=7.0Hz), 2.67
δ: 1.75–1.82 (2H, m), 1.95 (2H, brs), 2.42 (3H, s), 2.78 (2H, (4H, brs), 2.95 (4H, brs), 3.11 (2H, t, J=7.0Hz), 6.29 (1H,
brs), 2.92–3.04 (4H, m), 3.07–3.05 (2H, m), 3.35 (4H, brs), s), 6.96 (1H, m), 7.02 (1H, d, J=7.5Hz), 7.10 (1H, dd, J=8.5,
3.75 (3H, s), 6.22 (1H, s), 6.85 (2H, d, J=8.5Hz), 6.91 (2H, 1.5Hz), 7.19 (2H, m), 7.26 (1H, d, J=1.5Hz), 7.39 (1H, d,
d, J=8.5Hz), 7.17 (1H, dd, J=8.0Hz, 2.0Hz), 7.18 (1H, d, J=8.5Hz), 7.46–7.43 (2H, m), 7.54–7.51 (3H, m). ESI-MS
J=2.0Hz), 7.46 (1H, d, J=8.0Hz). ESI-MS m/z: 439.2 [M+H]+. m/z: 485.2 [M+H]+. HR-MS: Calcd for C30H33N2O2S [M+H]+
HR-MS: Calcd for C25H31N2O3S [M+H]+ 439.2050, Found 485.2257, Found 485.2259. Anal. Calcd for C30H32N2O2S: C,
439.2053. Anal. Calcd for C25H30N2O3S: C, 68.46; H, 6.89; N, 74.35; H, 6.66; N, 5.78; S, 6.62. Found: C, 74.55; H, 6.81; N,
6.39; S, 7.31. Found: C, 68.51; H, 7.02; N, 6.35; S, 7.16.
5.69; S, 6.60.
4-Phenyl-7-((2-(4-(o-tolyl)piperazin-1-yl)ethyl)thio)-2H-
7-((4-(4-(2-Methoxyphenyl)piperazin-1-yl)butyl)thio)-4-
chromen-2-one (13): Yield 16%. Yellow oil. IR (KBr) cm−1: phenyl-2H-chromen-2-one (18): Yield 26%. White solid. mp
3056, 2939, 2876, 2806, 1729, 1600, 1444, 1373, 1350, 1222, 87–89°C. IR (KBr) cm−1: 3050, 2998, 2887, 2864, 1729, 1593,
1128, 1072, 966, 852, 765. 1H-NMR (CDCl3) δ: 2.31 (3H, 1445, 1373, 1245, 1135, 1072, 1025, 966, 873, 765. H-NMR
1
s), 2.75–2.85 (6H, m), 2.95 (4H, brs), 3.20–3.23 (2H, m), (CDCl3) δ: 1.78–1.80 (4H, m), 2.50 (2H, t, J=6.0Hz), 2.67 (4H,

January 2013
23
brs), 2.95 (2H, brs), 3.19 (4H, brs), 3.84 (3H, s), 6.29 (1H, s), 1.83–1.85 (4H, m), 2.28 (3H, s), 2.65 (2H, t, J=7.0Hz), 2.71
6.88 (1H, d, J=8.0Hz), 6.92–6.95 (m, 2H), 7.01–7.03 (m, 1H), (4H, brs), 3.09 (2H, t, J=7.0Hz), 3.20–3.18 (4H, m), 6.29 (1H,
7.10 (1H, dd, J=8.5, 2.0Hz), 7.26 (1H, d, J=2.0Hz), 7.38 (1H, s), 6.85 (2H, d, J=8.0Hz), 7.09 (2H, d, J=8.0Hz), 7.12 (1H, dd,
d, J=8.5Hz), 7.46–7.42 (2H, m), 7.54–7.51 (3H, m). ESI-MS J=8.0, 1.5Hz), 7.26 (1H, d, J=2.0Hz), 7.39 (1H, d, J=8.5Hz),
m/z: 501.2 [M+H]+. HR-MS: Calcd for C30H33N2O3S [M+H]+ 7.45–7.42 (2H, m), 7.53–7.51 (3H, m). ESI-MS m/z: 485.2
501.2206, Found 501.2215. Anal. Calcd for C30H32N2O3S: C, [M+H]+. HR-MS: Calcd for C30H33N2O2S [M+H]+ 485.2257,
71.97; H, 6.44; N, 5.60; S, 6.40. Found: C, 71.91; H, 6.50; N, Found 485.2257. Anal. Calcd for C30H32N2O2S: C, 74.35; H,
5.89; S, 6.21.
6.66; N, 5.78; S, 6.62. Found: C, 74.37; H, 6.73; N, 5.87; S,
4-Phenyl-7-((2-(4-(p-tolyl)piperazin-1-yl)ethyl)thio)-2H- 6.58.
chromen-2-one (19): Yield 21%. Pale yellow solid. mp
7-((4-(4-(4-Methoxyphenyl)piperazin-1-yl)butyl)thio)-4-
108–109°C. IR (KBr) cm−1: 3064, 2938, 2878, 2815, 1713, phenyl-2H-chromen-2-one (24): Yield 25%. White solid. mp
1597, 1514, 1443, 1373, 1210, 1125, 1075, 975, 870, 874, 767. 105–106°C. IR (KBr) cm−1: 3063, 2997, 2887, 2833, 1729,
1H-NMR (CDCl3) δ: 2.30 (3H, s), 2.85 (6H, m), 3.20 (6H, brs), 1593, 1511, 1445, 1373, 1245, 1162, 1135, 1072, 1037, 966, 873,
1
6.29 (1H, s), 6.85 (2H, d, J=8.0Hz), 7.09 (2H, d, J=8.0Hz), 817, 766. H-NMR (CDCl3) δ: 1.83–1.85 (4H, m), 2.65 (2H,
7.15 (1H, d, J=8.0Hz), 7.26 (1H, d, J=2.0Hz), 7.39 (1H, d, t, J=6.0Hz), 2.71(4H, brs), 3.10 (2H, t, J=6.0Hz), 3.22–3.20
J=8.5Hz), 7.45–7.42 (2H, m), 7.53–7.51 (3H, m). ESI-MS (4H, m), 3.83 (3H, s), 6.29 (1H, s), 6.80 (2H, d, J=8.5Hz), 6.92
m/z: 457.2 [M+H]+. HR-MS: Calcd for C28H29N2O2S [M+H]+ (2H, d, J=8.5Hz), 7.12 (1H, dd, J=8.0, 2.0Hz), 7.26 (1H, d,
457.1944, Found 457.1953. Anal. Calcd for C28H28N2O2S: C, J=2.0Hz), 7.36 (1H, d, J=8.5Hz), 7.45–7.42 (2H, m), 7.53–7.51
73.65; H, 6.18; N, 6.14; S, 7.02. Found: C, 73.48; H, 6.31; N, (3H, m). ESI-MS m/z: 501.2 [M+H]+. HR-MS: Calcd for
6.21; S, 6.86.
C30H33N2O3S [M+H]+ 501.2206, Found 501.2212. Anal. Calcd
7-((2-(4-(4-Methoxyphenyl)piperazin-1-yl)ethyl)thio)-4- for C30H32N2O3S: C, 71.97; H, 6.44; N, 5.60; S, 6.40. Found: C,
phenyl-2H-chromen-2-one (20): Yield 25%. Yellow oil. IR 72.14; H, 6.56; N, 5.43; S, 6.35.
(KBr) cm−1: 3060, 2938, 2815, 1732, 1597, 1510, 1445, 1372,
Pharmacology The antagonistic activity (pA2) of each
1
1242, 1133, 1074, 1006, 967, 821, 767. H-NMR (CDCl3) δ: compound was measured by using the methods similar to
2.73–2.85 (6H, m), 3.20–3.20 (6H, m), 3.79 (3H, s), 6.29 (1H, those described previously.30–33) After light ether anesthesia,
s), 6.85 (2H, d, J=8.0Hz), 6.90 (2H, d, J=8.0Hz), 7.12 (1H, male Wistar rats (275–300g) were killed by cervical disloca-
d, J=8.5Hz), 7.26 (1H, d, J=2.0Hz), 7.36 (1H, d, J=8.5Hz), tion, and anococcygeus smooth muscles were isolated, freed
7.41–7.45 (2H, m), 7.53–7.50 (3H, m). ESI-MS m/z: 473.2 from adhering connective tissue, and set up rapidly under 1g
[M+H]+. HR-MS: Calcd for C28H29N2O3S [M+H]+ 473.1893, of resting tension in 20mL organ baths containing Krebs–
Found 473.1895. Anal. Calcd for C28H28N2O3S: C, 71.16; H, Henseleit solution (118.1mm NaCl, 4.7mm KCl, 2.5mm CaCl2,
5.97; N, 5.93; S, 6.78. Found: C, 71.15; H, 5.99; N, 5.86; S, 1.16 mm MgSO4, 1.0mm NaH2PO4, 25mm NaHCO3, and
6.82.
11.1 mm glucose) kept at 37°C and aerated with 5% CO2–95%
4-Phenyl-7-((3-(4-(p-tolyl)piperazin-1-yl)propyl)thio)-2H- O2 at pH 7.4. The tissues were equilibrated for 60min with
chromen-2-one (21): Yield 23%. Colorless plate crystals. mp washing every 15min. Cumulative concentration–response
126–128°C. IR (KBr) cm−1: 3059, 2971, 2875, 2821, 1717, curves to phenylephrine (3×10−9 to 10−4 m) were obtained by
1593, 1513, 1451, 1373, 1238, 1161, 1075, 1008, 970, 832, the method of Van Rossum. Following the first phenylephrine
771. 1H-NMR (CDCl3) δ: 1.95–1.98 (2H, m), 2.25 (3H, s), curve, the smooth muscles were incubated with tested com-
2.60 (2H, t, J=7.0Hz), 2.70 (4H, brs), 3.09 (2H, t, J=6.0Hz), pound (one concentration of the antagonist was used in each
3.20 (4H, brs), 6.29 (1H, s), 6.85 (2H, d, J=8.0Hz), 7.09 smooth muscle in every experiment) for 15min and the next
(2H, d, J=8.0Hz), 7.12 (1H, dd, J=8.0, 1.5Hz), 7.26 (1H, d, cumulative concentration curve to phenylephrine was gener-
J=1.5Hz), 7.39 (1H, d, J=8.5Hz), 7.45–7.42 (2H, m), 7.53–7.51 ated. The pA2 values of each compound were calculated ac-
(3H, m). ESI-MS m/z: 471.2 [M+H]+. HR-MS: Calcd for cording to Schild’s graphical method.
C29H31N2O2S [M+H]+ 471.2101, Found 471.2095. Anal. Calcd
for C29H30N2O2S: C, 74.01; H, 6.43; N, 5.95; S, 6.81. Found: C, modeling studies were carried out using Catalyst in Discov-
74.13; H, 6.65; N, 5.74; S, 6.73. ery Studio 2.1 (Accelrys, San Diego, CA) running on either a
Computational Methods The computational molecular
7-((3-(4-(4-Methoxyphenyl)piperazin-1-yl)propyl)thio)-4- Centrino or Centrino Duo processor (Intel, Santa Clara, CA,
phenyl-2H-chromen-2-one (22): Yield 20%. Colorless granular U.S.A.). The phamacophore model was generated according
crystals. mp 113–115°C. IR (KBr) cm−1: 3045, 2987, 2817, to the previous method reported by Baobaro et al. The struc-
1709, 1599, 1489, 1444, 1372, 1311, 1231, 1128, 1075, 967, 863, tures of synthesized compounds were sketched as sdf files.
1
763. H-NMR (CDCl3) δ: 1.95–1.98 (2H, m), 2.67–2.60 (6H, The three-dimensional molecular structures were produced
m), 3.13–3.08 (6H, m), 3.79 (3H, s), 6.29 (1H, s), 6.85 (2H, d, using up to 255 conformers with the “best conformer gen-
J=8.5Hz), 6.93 (2H, d, J=8.5Hz), 7.12 (1H, dd, J=8.0, 1.5Hz), eration” method, allowing a maximum energy threshold of
7.26 (1H, d, J=2.0Hz), 7.36 (1H, d, J=8.5Hz), 7.45–7.42 (2H, 20kcalmol−1 for each conformer. Using the Ligand Pharmaco-
m), 7.53–7.51 (3H, m). ESI-MS m/z: 487.2 [M+H]+. HR-MS: phore Mapping protocol, the “Best Mapping” was performed
Calcd for C29H31N2O3S [M+H]+ 487.2050, Found 487.2058. with the “rigid fitting method” and maximum omitted features
Anal. Calcd for C29H30N2O3S: C, 71.58; H, 6.21; N, 5.76; S, set to zero.
6.59. Found: C, 71.70; H, 6.19; N, 5.83; S, 6.37.
4-Phenyl-7-((4-(4-(p-tolyl)piperazin-1-yl)butyl)thio)-2H-
Acknowledgement This research work was financially
chromen-2-one (23): Yield 24%. White solid. mp 119–120°C. supported by Program for Changjiang Scholars and Innovative
IR (KBr) cm−1: 3059, 2970, 2876, 2836, 2813, 1716, 1599, 1447, Research Team in University (PCSIRT-IRT1193) and A Proj-
1
1375, 1237, 1131, 1073, 974, 862, 748. H-NMR (CDCl3) δ: ect Funded by the Priority Academic Program Development of

24
Vol. 61, No. 1
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