Synthesis and in-vitro anti-hepatitis-B virus activity of 6H-[1]benzothiopyrano[4,3-b] quinolin-10-ols

Article abstract of DOI:10.1002/ardp.200900070

A series of 9-methoxy-6H-[1]benzothiopyrano[4,3-b]quinolin-10-ols with a Mannich side chain were synthesized and evaluated for their anti-Hepatitis B virus (HBV) activity in HepG2.2.15 cells. Some compounds showed significant anti-HBV activity with IC₅₀ values less than 41 μM. Among them, compound 9b was the most effective anti-HBV agent (IC₅₀ = 1.7 μM, SI = 60.3).

Full text of DOI:10.1002/ardp.200900070

Arch. Pharm. Chem. Life Sci. 2009, 342, 507–512
W. Jia et al.
507
Full Paper
Synthesis and In-Vitro Anti-Hepatitis-B Virus Activity of
6H-[1]Benzothiopyrano[4,3-b] quinolin-10-ols
Wei Jia1, Yanfang Zhao1, Rongdong Li2, Yanjiao Wu1, Zebiao Li1, and Ping Gong1
1 School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
2 School of Pharmacy, Hunan University of Traditional Chinese Medicine, Changsha, China
A series of 9-methoxy-6H-[1]benzothiopyrano[4,3-b]quinolin-10-ols with a Mannich side chain
were synthesized and evaluated for their anti-Hepatitis B virus (HBV) activity in HepG2.2.15 cells.
Some compounds showed significant anti-HBV activity with IC50 values less than 41 lM. Among
them, compound 9b was the most effective anti-HBV agent (IC50 = 1.7 lM, SI = 60.3).
Keywords: Anti-HBV activity / 6H-[1]Benzothiopyrano[4,3-b]quinolin-10-ols / Synthesis /
Received: April 3, 2009; accepted: April 29, 2009
DOI 10.1002/ardp.200900070
Introduction
Hepatitis B virus (HBV) infection is one of the most preva-
lent viral diseases in the world [1]. There are approxi-
mately 400 million people with chronic HBV infection,
which can lead to cirrhosis of the liver, liver failure, liver
cancer, and even death. Currently approved treatments
for HBV infection include the immunomodulatory
agents and nucleo(s/t)ide analogues. a-Interferon has
been used for chronic hepatitis B for years, but only
about 30l40% of the patients respond to the treatment
and the therapy is associated with several side effects [2].
Approved nucleoside analogues of chronic hepatitis B
treatment include lamivudine, adefovir dipivoxil, entica-
vir, telbivudine, and tenofovir. As the nucleo(s/t)ide ana-
logues inhibit HBV replication through their unique
interaction with the HBV polymerase, emergence of HBV
variants resistant to anti-viral therapy is facing all the
nucleo(s/t)ide analogues [3]. It is thus necessary to develop
anti-HBV agents with novel structures different from
nucleo(s/t)ide analogues [4].
Figure 1. Structure of quinolines and target compounds.
potent activity against HBV [5]. Therefore, it was neces-
sary to synthesize additional analogues of this series for
the development of more selective and more potent anti-
viral agents. Our approach was to modify the nucleus by
preparing a quinoline with a benzothiopyran ring fused
across the 2- and 3-positions to obtain the 6H-[1]benzo-
thiopyrano[4,3-b]quinoline ring system (Fig. 1). Herein,
we prepared a series of 9-methoxy-6H-[1]benzothiopyr-
ano[4,3-b]quinolin-10-ols and evaluated their anti-HBV
activity in HepG2.2.15 cells.
Results and discussion
More recently, we have reported a series of 7-hydroxy-
6-methoxyquinolines with a Mannich side chain at the 8-
position, and most compounds were found to show
Chemistry
The synthesis of the title compounds is illustrated in
Scheme 1.
2-Amino-4-(benzyloxy)-5-methoxybenzalde-
hyde 4 was prepared in moderate overall yield from the
commercially available 4-hydroxy-3-methoxybenzalde-
hyde 1 following the reported preparation procedure [5].
Subsequently, condensation of compound 4 with the
Correspondence: Ping Gong, School of Pharmaceutical Engineering,
Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe Dis-
trict, 110016 Shenyang, Liaoning, P. R. China.
E-mail: gongpinggp@126.com
Fax: +86 24 2398-6429
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

508
W. Jia et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 507–512
Reagents and conditions: a) Benzyl chloride, K2CO3, DMF, 808C, 3 h; b) HNO3, 408C, 5 h; c) Zn, C2H5OH, reflux, 8 h; d) C2H5ONa,
C2H5OH, reflux, 15 h; e) HCl, AcOH, 808C, 15 h; f) amine, HCHO, AcOH, 458C, 2 h; g) NaBO3 6 4H2O, AcOH, 458C, 3l5 h; h) HCl,
1,4-dioxane, 808C, 3 h.
Scheme 1. Synthesis of substituted 9-methoxy-6H-[1]benzothiopyrano[4,3-b]quinolin-10-ols.
known [6–9] thiochromanone derivatives in the presence (IC50), and the 50% cytotoxic concentration (CC50) on
of C2H5ONa gave the corresponding compounds 5a–g, HepG2.2.15 are shown in Table 1. Lamivudine (3-TC) was
which were converted to the important intermediates used in these assays as reference antiviral drug.
6a–g in a mixture of concentrated hydrochloric acid and
It was found that the Mannich side chain had some
acetic acid (1 : 1, v/v) in a one-pot reaction. Compounds effect on anti-HBV activity. In the 3-F derivatives, com-
6a–g were reacted with formaldehyde and the proper pounds 7g–i with a cyclic amine displayed a more potent
amine in acetic acid to obtain the target compounds 7a–
anti-HBV activity than lamivudine, while compound 7f
m. The oxidation of compounds 7a–d with sodium per- with a dimethylamino group did not show any activity
borate tetrahydrate in acetic acid resulted in the target up to its 50% cytotoxic concentration. In general, piperi-
compounds 8a–d, respectively. By heating with imida- dine derivatives (7b, 7c, 7k, and 7m) showed remarkable
zole or 2-methylimidazole in 1,4-dioxane, the amino- inhibition of HBV DNA with IC50 values ranging between
exchange reaction of the dimethylamino analogue 7f 1.6 and 40.1 lM.
gave compounds 9a, b.
As we investigated the substituents on the D ring, sev-
eral substituents, such as 2-F, 2-MeO, 3-F, and 3-Me, were
found to be acceptable. Although the 2-Me derivative 7j
Pharmacology
The anti-HBV activity of compounds 7–9 was assessed in had no anti-HBV activity, introduction of an additional
confluent cultures of the HepG2.2.15 cells that chroni- methyl at the 4-position resulted in compound 7m with
cally produce infectious HBV [10–12]. The concentrations potent anti-HBV activity against HBV DNA with an IC50
required to inhibit 50% of HBeAg, HbsAg, and HBV DNA value of 12.9 lM.
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Arch. Pharm. Chem. Life Sci. 2009, 342, 507–512
6H-[1]Benzothiopyrano[4,3-b]quinolin-10-ols
509
Table 1. The substituents, cytotoxicity, and anti-HBV activity of compounds 7a–m, 8a–d, and 9a–b and lamivudine (3-TC).
DNA
SIc)
–
2.7
1.1
7.4
–
–
2.4
5.8
1.8
–
6.0
–
3.1
–
–
HBeAg
SIc)
HBsAg
IC50 (lM)b) SIc)
No.
R1
NR2R3
CC50 (lM)a) IC50 (lM)b)
IC50 (lM)b)
7a
7b
7c
7d
7e
7f
7g
7h
7i
2-F
2-F
3-Me
3-Me
3-Me
3-F
3-F
3-F
3-F
2-Me
2-MeO
2,3-diMeO
2,4-diMe
2-F
morpholino
piperidin-1-yl
piperidin-1-yl
pyrrolidin-1-yl
morpholino
dimethylamino
morpholino
piperidin-1-yl
pyrrolidin-1-yl
piperidin-1-yl
piperidin-1-yl
morpholino
piperidin-1-yl
morpholino
piperidin-1-yl
piperidin-1-yl
pyrrolidin-1-yl
74.8
108.4
25.3
47.2
10.1
27.7
60.5
33.6
21.6
15.7
9.7
–
40.1
32.2
6.4
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
2.2
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
25.2
5.8
12.0
–
7j
7k
7l
1.6
26.1
40.7
9.6
–
12.9
–
7m
8a
8b
8c
8d
9a
9b
3TC
–
–
2-F
24.1
29.2
26.2
78.4
101.7
2183.1
–
–
–
–
2.6
17.2
–
–
–
9.32
1.7
–
–
–
3-Me
3-Me
3-F
–
–
–
60.3
9.1
12.0
–
–
3-F
1.7
240
–
–
–
a)
Means 50% cytotoxic concentration in HepG2.2.15 cells.
Means 50% inhibitory concentration.
Selectivity index (SI: CC50 / IC50); – means no antiviral activity at the concentration lower than its CC50.
b)
c)
The effect of the oxidation state of the sulfur atom on series contains a potent inhibitor of HBV, compound 9b,
the anti-HBV activity was dramatic in this series. The sul- which displayed notable in-vitro anti-HBV activity and the
finyl derivatives 8b–d showed potent activity against best selectivity index.
HBsAg or HBeAg, while the corresponding sulfide deriv-
atives 7b–d showed more selectivity towards HBV DNA. It The authors have declared no conflict of interest.
is noteworthy that the sulfinyl derivatives tend to be
more toxic. The sulfinyl derivative 8a had about 8-fold
higher cytotoxicity to HepG2.2.15 cells than the corre-
sponding sulfide derivative 7a.
Experimental
Moreover, as the basic alkylamine or cyclic amine
groups were replaced in compounds 7f–i by a neutral
aromatic amino group, compounds 9a, b showed less tox-
icity. Compound 9b with a 2-methyl-1H-imidazol-1-yl
group was the most potent inhibitor in this series with
an IC50 value of 1.7 lM and a SI value of 60.3, which was
more potent than lamivudine (IC50 = 240 lM, SI = 9.1).
Chemistry
All chemicals were obtained from commercial suppliers and
were used without further purification. Melting points were
determined by capillary tube method and are uncorrected. Mass
spectra (MS) were taken in ESI mode on Agilent 1100 LC-MS (Agi-
lent, Palo Alto, CA, USA). 1H-NMR spectra were performed using
Bruker 300 MHz spectrometers (Bruker Bioscience, Billerica, MA,
USA) with TMS as an internal standard. Elemental analysis was
determined on a Carlo-Erba 1106 Elemental analysis instrument
(Carlo Erba, Milan, Italy). The IR spectra were recorded by means
of the KBr pellet technique on a Bruker FTS 135 spectrometer.
Conclusion
General procedure for the preparation of 6a–g
In conclusion, a series of novel 9-methoxy-6H-[1]benzo-
thiopyrano[4,3-b]quinolin-10-ol derivates was synthe-
sized and evaluated for their anti-HBV activity. As for the
Mannich side chain, the 2-methyl-1H-imidazol-1-yl group
was preferred for potent anti-HBV activity and good selec-
tivity. The sulfinyl derivative 8b effectively suppressed
the secretion of HBsAg with an IC50 value of 2.6 lM. This
To a solution of EtONa (0.15 mol) in EtOH (200 mL) was added
substituted 3,4-dihydro-2H-1-benzothiopyran-4-one (0.10 mol)
and 4-benzyloxy-5-methoxy-2-nitro-benzaldehyde 4 (0.10 mol)
[5]. The resulting mixture was heated at reflux for 15 h. After
cooling to ambient temperature, EtOH was removed under
reduced pressure to give the crude compounds 5a–g, which
were used directly. To the crude 5a–g was added AcOH (150 mL)
and concentrated HCl (75 mL). The resulting suspension was
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W. Jia et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 507–512
heated at reflux for 15 h, then cooled. The yellow solid was fil-
tered and washed with a mixture of AcOH (10 mL) and concen-
trated HCl (5 mL) to give 6a–g.
crude product. After purification by flash column chromatogra-
phy, 7a–m were obtained as a yellow solid.
2-Fluoro-9-methoxy-11-(morpholinomethyl)-6H-
3-Fluoro-9-methoxy-6H-[1]benzothiopyrano[4,3-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7a
b]quinolin-10-ol 6a
Yield: 70%; m.p.: 2158C (dec); IR (KBr): 1256.4, 1383.9, 1469.3,
Yield: 21%; m.p.: A3308C; 1H-NMR (DMSO-d6) d: 4.02 (s, 3H), 4.15 (s,
2H), 7.40 (m, 1H), 7.50 (m, 2H), 7.75 (s, 1H), 8.16 (s, 1H), 8.45 (m,
1H); MS (ESI) m/z: 314.1 [M + H+].
1569.8, 2849.3, 2955.9, 3444.0 cm– 1
;
1H-NMR (DMSO-d6,
300 MHz) d: 2.71 (m, 4H), 3.67 (m, 4H), 3.93 (s, 3H), 4.21 (s, 2H),
4.53 (s, 2H), 7.20–7.28 (m, 2H), 7.45–7.50 (m, 1H), 8.07 (s, 1H),
8.21 (m, 1H);); MS (ESI) m/z: 413.1 [M + H+]. Anal. Calcd. for
C22H21FN2O3S: C, 64.06; H, 5.13; N, 6.79. Found: C, 63.91; H, 5.24;
N, 6.80.
2,9-Dimethoxy-6H-[1]benzothiopyrano[4,3-b]quinolin-10-
ol 6b
Yield: 30%; m.p.: A3308C; 1H-NMR (DMSO-d6, 300 MHz) d: 3.97 (s,
3H), 4.08 (s, 3H), 4.20 (s, 2H), 7.20 (d, J = 8.4 Hz, 1H), 7.51 (s, 1H),
7.57 (d, J = 8.4 Hz, 1H), 7.63 (s, 1H), 7.76 (s, 1H), 8.40 (s, 1H) ; MS
(ESI) m/z: 326.1 [M + H+].
2-Fluoro-9-methoxy-11-(piperidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7b
Yield: 64%; m.p.: 2508C (dec); IR (KBr): 1256.7, 1384.9, 1470.8,
1
1568.2, 1600.3, 2853.0, 2934.2, 3398.0 cm– 1; H-NMR (DMSO-d6,
300 MHz) d: 1.50–1.60 (m, 6H), 2.64 (m, 4H), 3.9 (s, 3H), 4.19 (s,
2H), 4.78 (s, 2H), 7.19–7.23 (m, 2H), 7.44–7.48 (m, 1H), 8.03 (s,
1H), 8.15 (m, 1H); MS (ESI) m/z: 411.2 [M + H+]. Anal. Calcd. for
C23H23FN2O2S: C, 67.29; H, 5.65; N, 6.82. Found: C, 67.00; H, 5.70;
N, 6.71.
9-Methoxy-3-methyl-6H-[1]benzothiopyrano[4,3-
b]quinolin-10-ol 6c
Yield: 26%; m.p.: A3308C; 1H-NMR (DMSO-d6, 300 MHz) d: 2.47 (s,
3H), 4.08 (s, 3H), 4.20 (s, 2H), 7.26 (d, J = 8.1 Hz, 1H), 7.50 (s, 1H),
7.69 (s, 1H), 7.76 (s, 1H), 7.97 (s, 1H),8.43 (d, J = 8.1 Hz, 1H); MS
(ESI) m/z: 310.1 [M + H+].
9-Methoxy-3-methyl-11-(piperidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7c
9-Methoxy-2-methyl-6H-[1]benzothiopyrano[4,3-
Yield: 69%; m.p.: 2388C (dec); IR (KBr): 1157.8, 1256.6, 1384.0,
b]quinolin-10-ol 6d
1479.7, 1598.7, 1623.2, 2935.8, 3002.3, 3348.6 cm– 1 1H-NMR
;
Yield: 42%; m.p.: A3308C; 1H-NMR (DMSO-d6, 300 MHz) d: 2.36 (s,
3H), 4.08 (s, 3H), 4.20 (s, 2H), 7.21 (d, J = 7.8 Hz, 1H), 7.53 (s, 1H),
7.76 (s, 1H), 7.77 (d, J = 7.8 Hz, 1H), 8.19 (s, 1H), 8.35 (s, 1H); MS
(ESI) m/z: 310.1 [M + H+].
(DMSO-d6) d: 1.53–1.74 (m, 6H), 2.34 (s, 3H), 3.41 (m, 4H), 4.00 (s,
3H), 4.21 (s, 2H), 4.82 (s, 2H), 7.22 (d, 1H), 7.25 (s, 1H), 7.46 (s, 1H),
8.12 (s, 1H), 8.44 (d, 1H); MS (ESI) m/z: 407.2 [M + H+]. Anal. Calcd.
for C24H26N2O2S: C, 70.90; H, 6.45; N, 6.89. Found: C, 70.88; H,
6.38; N, 6.74.
2-Fluoro-9-methoxy-6H-[1]benzothiopyrano[4,3-
b]quinolin-10-ol 6e
9-Methoxy-3-methyl-11-(pyrrolidin-1-ylmethyl)-6H-
Yield: 26%; m.p.: A3308C, 1H-NMR (DMSO-d6, 300 MHz) d: 3.96 (s,
3H), 4.20 (s, 2H), 7.20 (m, 2H), 7.45–7.50 (m, 2H), 8.07 (s, 1H), 8.21
(m, 1H); MS (ESI) m/z: 314.1 [M + H+].
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7d
Yield: 80%; m.p.: 2768C (dec); IR (KBr): 1257.2, 1384.1, 1460.8,
1482.3, 1598.4, 2924.7, 3416.9 cm– 1
;
1H-NMR (DMSO-d6,
300 MHz) d: 1.84 (m, 4H), 2.33 (s, 3H), 2.8 (m, 4H), 3.91 (s, 3H),
4.16 (s, 2H), 4.64 (s, 2H), 7.17 (d, J = 7.8 Hz, 1H), 7.22 (s, 1H), 7.23 (s,
1H), 7.99 (s, 1H), 8.35 (d, J = 7.8 Hz, 1H); MS (ESI) m/z: 393.2 [M +
H+]. Anal. Calcd. for C23H24N2O2S: C, 70.38; H, 6.16; N, 7.14. Found:
C, 70.38; H, 6.18; N, 7.10.
9-Methoxy-2,4-dimethyl-6H-[1]benzothiopyrano[4,3-
b]quinolin-10-ol 6f
Yield: 22%; m.p.: A3308C; 1H-NMR (DMSO-d6, 300 MHz) d: 2.32 (s,
3H), 2.38 (s, 3H), 4.00 (s, 3H), 4.20 (s, 2H), 7.20 (s, 1H), 7.53 (s, 1H),
7.76 (s, 1H), 8.18 (s, 1H), 8.23 (s, 1H); MS (ESI) m/z: 324.1 [M + H+].
9-Methoxy-3-methyl-11-(morpholinomethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7e
2,3,9-Trimethoxy-6H-[1]benzothiopyrano[4,3-b]quinolin-
Yield: 77%; m.p.: 1858C (dec); IR (KBr): 1254.2, 1383.0, 1469.1,
1596.9, 2852.1, 2912.2, 2956.4, 3443.3 cm– 1; 1H-NMR (DMSO-d6)
d: 2.33 (s, 3H), 2.60 (m, 4H), 3.64 (m, 4H), 3.91 (s, 3H), 4.16 (s, 2H),
4.46 (s, 2H), 7.22 (m, 3H), 7.99 (s, 1H), 8.38 (d, 1H); MS (ESI) m/z:
409.2 [M + H+]. Anal. Calcd. for C23H24N2O3S: C, 67.62; H, 5.92; N,
6.86. Found: C, 67.57; H, 5.98; N, 6.70.
10-ol 6g
Yield: 40%; m.p.: A3308C; 1H-NMR (DMSO-d6, 300 MHz) d: 3.85 (s,
3H), 3.97 (s, 3H), 4.02 (s, 3H), 4.20 (s, 2H), 7.00 (s, 1H), 7.53 (s, 1H),
7.76 (s, 1H), 8.10 (s, 1H), 8.15 (s, 1H); MS (ESI) m/z: 356.1 [M + H+].
General procedure for the preparation of 7a–m
To a solution of appropriate amine (25 mmol) in acetic acid
(20 mL) was added 37% formaldehyde (11 mmol). The mixture
was stirred at room temperature for 30 min. To this mixture was
added compound 6 (10 mmol). The reaction mixture was stirred
at 458C for 2 h. The mixture was concentrated under reduced
pressure. The residue was poured into water and neutralized
with 25% ammonia solution. The solid was filtered to give the
11-((Dimethylamino)methyl)-3-fluoro-9-methoxy-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7f
Yield: 56%; m.p.: 2188C (dec); IR (KBr): 1247.5, 1384.2, 1483.2,
1
1597.5, 2972.4 cm– 1; H-NMR (DMSO-d6) d: 2.84 (s, 6H), 4.02 (s,
3H), 4.28 (s, 2H), 4.84 (s, 2H), 7.19–7.25 (m, 1H), 7.34–7.35 (m,
1H), 7.5 (s, 1H), 8.16 (s, 1H), 8.63–8.68 (m, 1H); MS (ESI) m/z: 371.1
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Arch. Pharm. Chem. Life Sci. 2009, 342, 507–512
6H-[1]Benzothiopyrano[4,3-b]quinolin-10-ols
511
[M + H+] Anal. Calcd. for C20H19FN2O2S: C, 64.85; H, 5.17; N, 7.56.
Found: C, 64.79; H, 5.20; N, 7.48.
m/z: 455.2 [M + H+]. Anal. Calcd for C24H26N2O5S: C, 63.42; H, 5.77;
N, 6.16. Found: C, 64.40; H, 5.83; N, 6.11.
3-Fluoro-9-methoxy-11-(morpholinomethyl)-6H-
9-Methoxy-2,4-dimethyl-11-(piperidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7g
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7m
Yield: 78%; m.p.: 2648C (dec); IR (KBr): 1244.4, 1381.7, 1411.3,
Yield: 86%; m.p.: 1878C (dec); IR (KBr): 1263.1, 1385.5, 1487.8,
1
1471.9, 1591.2, 2842.4, 2954.9, 3443.3 cm– 1; H-NMR (DMSO-d6)
1613.0, 2534.0, 2942.8, 3437.1 cm– 1
;
1H-NMR (DMSO-d6,
d: 2.61 (m, 4H), 3.64 (m, 4H), 3.91 (s, 3H), 4.23 (s, 2H), 4.46 (s, 2H),
7.20–7.26 (m, 2H), 7.31-7.35 (m, 1H), 8.02 (s, 1H), 8.49–8.54 (m,
1H); MS (ESI) m/z: 413.1 [M + H+]. Anal. Calcd. for C22H21FN2O3S: C,
64.06; H, 5.13; N, 6.79. Found: C, 64.05; H, 5.14; N, 6.79.
300 MHz) d: 1.62–1.84 (m, 6H), 2.32 (s, 3H), 2.38 (s, 3H), 3.17–
3.47 (m, 4H), 4.03 (s, 3H), 4.18 (s, 2H), 4.86 (s, 2H), 7.16 (s, 1H), 7.49
(s, 1H), 8.15 (s, 1H), 8.20 (s, 1H); MS (ESI) m/z: 421.2 [M + H+]. Anal.
Calcd. for C25H28N2O2S: C, 71.40; H, 6.71; N, 6.66. Found: C, 71.33;
H,6.83 ; N, 6.51.
3-Fluoro-9-methoxy-11-(piperidin-1-ylmethyl)-6H-
General procedure for the preparation of 8a–d
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7h
A solution of compound 7 (10 mmol) and sodium perborate tet-
rahydrate (10 mmol) in acetic acid (40 mL) was heated to 458C
for 3 to 5 hours. The solvent was evaporated in vacuo, and poured
into water (100 mL). The precipitate was filtered to give the
crude product. After purification by flash column chromatogra-
phy, 8a–d were obtained as a yellow solid.
Yield: 64%; m.p.: 2408C (dec); IR (KBr): 1259.9, 1383.9, 1481.0,
1598.3, 2542.8, 2933.0 cm– 1 1H-NMR (DMSO-d6, 300 MHz) d:
;
1.45–1.77 (m, 6H), 3.13–3.43 (m, 4H), 4.02 (s, 3H), 4.28 (s, 2H),
4.85 (s, 2H), 7.20–7.27 (m, 1H), 7.34–7.38 (m, 1H), 7.50 (s, 1H),
8.15 (s, 1H), 8.59–8.64 (m, 1H); MS (ESI) m/z: 411.2 [M +H+]. Anal.
Calcd. for C23H23FN2O2S: C, 67.29; H, 5.65; N, 6.82. Found: C,
67.11; H, 5.73; N, 6.79.
2-Fluoro-9-methoxy-11-(morpholinomethyl)-6H-
3-Fluoro-9-methoxy-11-(pyrrolidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 5-oxide 8a
Yield: 80%; m.p.: 2208C (dec); IR (KBr): 1266.6, 1382.7, 1436.5,
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7i
1476.6, 1570.1, 1601.1, 2966.4, 3066.5, 3422.1 cm– 1 1H-NMR
;
Yield: 75%; m.p.: 2358C (dec); IR (KBr): 1250.7, 1381.8, 1460.0,
1595.1, 1713.3, 2830.5, 2930.7, 2962.4, 3445.2 cm– 1 1H-NMR
;
(DMSO-d6, 300 MHz) d: 2.66 (m, 4H), 3.66 (m, 4H), 3.94 (s, 3H), 4.46
(d, J = 15.0 Hz, 1H), 4.52 (s, 2H), 4.78 (d, J = 15.0 Hz, 1H), 7.31 (s,
1H), 7.49–7.55 (m, 1H), 7.98–8.02 (m, 1H), 8.24 (s, 1H), 8.33–3.37
(m, 1H); MS (ESI) m/z: 429.1 [M + 1+]. Anal. Calcd. for C22H21FN2O4S:
C, 61.76; H, 4.94; N, 6.54. Found: C, 61.50; H, 5.04; N, 6.50.
(DMSO-d6, 300 MHz) d: 2.30 (s, 3H), 2.35 (s, 3H), 2.54 (m, 4H), 3.58
(m, 4H), 3.96 (s, 3H), 4.00 (s, 2H), 4.15 (s, 2H), 7.10 (s, 1H), 7.38 (s,
1H), 8.14 (s, 1H), 8.24 (s, 1H); MS (ESI) m/z: 397.1 [M + H+]. Anal.
Calcd. for C22H21FN2O2S: C, 66.65; H, 5.34; N, 7.07. Found: C,
66.49; H, 5.38; N, 7.00.
2-Fluoro-9-methoxy-11-(piperidin-1-ylmethyl)-6H-
9-Methoxy-2-methyl-11-(piperidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 5-oxide 8b
Yield: 83%; m.p.: 2538C (dec); IR (KBr): 1248.5, 1383.9, 1482.7,
1599.3, 2950.2, 3421.2 cm– 1; 1H-NMR (DMSO-d6, 300 MHz) d: 1.61
(m, 6H), 2.67 (m, 4H), 3.91 (s, 3H), 4.44 (d, J = 15.0 Hz, 1H), 4.53 (s,
2H), 4.76 (d, J = 15.0 Hz, 1H), 7.25 (s, 1H), 7.47–7.54 (m, 1H),
7.96–8.01 (m, 1H), 8.20 (s, 1H), 8.28–8.32 (m, 1H); MS (ESI) m/z:
427.2 [M + 1+]. Anal. Calcd. for C23H23FN2O3S: C, 64.77; H, 5.44; N,
6.57. Found: C, 64.50; H, 5.53; N, 6.49.
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7j
Yield: 83%; m.p.: 2948C (dec); IR (KBr): 1257.8, 1384.2, 1475.2,
1589.5, 2950.4, 3410.8 cm– 1 1H-NMR (DMSO-d6, 300 MHz) d:
;
1.54–1.73 (m, 6H), 2.41 (s, 3H), 3.11 (m, 4H), 3.98 (s, 3H), 4.18 (s,
2H), 4.75 (s, 2H), 7.21 (d, J = 7.8 Hz, 1H), 7.34 (d, J = 7.8 Hz, 1H),
7.40 (s, 1H), 8.09 (s, 1H), 8.31 (s, 1H); MS (ESI) m/z: 407.2 [M + H+].
Anal. Calcd. for C24H26N2O2S: C, 70.90; H, 6.45; N, 6.89. Found: C,
70.84; H, 6.58; N, 6.75.
9-Methoxy-3-methyl-11-(piperidin-1-ylmethyl)-6H-
2,9-Dimethoxy-11-(piperidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7k
[1]benzothiopyrano[4,3-b]quinolin-10-ol 5-oxide 8c
Yield: 75%; m.p.: 2418C (dec); IR (KBr): 1248.4, 1383.4, 1467.6,
1
1599.2, 2962.1 cm– 1; H-NMR (DMSO-d6, 300 MHz) d: 1.51–1.62
Yield: 79%; m.p.: 2478C (dec); IR (KBr): 1232.1, 1384.2, 1485.0,
1
1591.9, 1662.3, 2835.8, 2936.5, 3428.2 cm– 1; H-NMR (DMSO-d6,
(m, 6H), 2.47 (s, 3H), 2.69 (m, 4H), 3.92 (s, 3H), 4.38 (d, J = 14.7 Hz,
1H), 4.54 (s, 2H), 4.69 (d, J = 14.7 Hz, 1H), 7.25 (s, 1H), 7.64 (d, J =
7.8 Hz, 1H), 7.68 (s, 1H), 8.16 (s, 1H), 8.45 (d, J = 7.8 Hz, 1H); MS
(ESI) m/z: 423.2 [M + 1+]. Anal. Calcd. for C24H26N2O3S: C, 68.22; H,
6.20; N, 6.63. Found: C, 68.19; H, 6.32; N, 6.49.
300 MHz) d: 1.45–1.91 (m, 6H), 3.18–3.46 (m, 4H), 3.89 (s, 3H),
4.03 (s, 3H), 4.20 (s, 2H), 4.87 (s, 2H), 7.03 (d, J = 8.4 Hz, 1H), 7.38
(d, J = 8.4 Hz, 1H),7.51 (s, 1H), 8.09 (s, 1H), 8.16 (s, 1H); MS (ESI) m/
z: 423.2 [M + H+]. Anal. Calcd. for C24H26N2O3S: C, 68.22; H, 6.20; N,
6.63. Found: C, 68.21; H, 6.34; N, 6.57.
9-Methoxy-3-methyl-11-(pyrrolidin-1-ylmethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 5-oxide 8d
Yield: 60%; m.p.: 3158C (dec); IR (KBr): 1248.4, 1383.4, 1467.6,
1599.2, 2962.1 cm– 1; 1H-NMR (DMSO-d6, 300 MHz) d: 1.84 (m, 4H),
2.47 (s, 3H), 2.77 (m, 4H), 3.91 (s, 3H), 4.23 (d, J = 14.7 Hz, 1H), 4.66
(s, 2H), 4.69 (d, J = 14.7 Hz, 1H), 7.23 (s, 1H), 7.63 (d, J = 7.8 Hz, 1H),
7.68 (s, 1H), 8.15 (s, 1H), 8.45 (d, J = 7.8 Hz, 1H); MS (ESI) m/z: 409.2
2,3,9-Trimethoxy-11-(morpholinomethyl)-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 7l
Yield: 77%; m.p.: 2398C (dec); IR (KBr): 1273.0, 1384.7, 1488.1,
1594.4, 2958.3 cm– 1;1H-NMR (DMSO-d6, 300 MHz) d: 2.70 (m, 4H),
3.70 (m, 4H), 3.83 (s, 3H), 3.91 (s, 3H), 4.02 (s, 3H), 4.20 (s, 2H), 4.95
(s, 2H), 6.99 (s, 1H), 7.49 (s, 1H), 8.08 (s, 1H), 8.11 (s, 1H); MS (ESI)
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

512
W. Jia et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 507–512
[M + 1+]. Anal. Calcd. for C23H24N2O3S: C, 67.62; H, 5.92; N, 6.86.
Found: C, 67.48; H, 6.02; N, 6.73.
Extracellular HBeAg and HBsAg levels were evaluated by semi-
quantitative enzyme immunoassay methods using commercial
kits (HBeAg, Diasorin, Inc, Stillwater, MN, USA; HBsAg, Abbott
Laboratories, Abbott Park, Il, USA). Intracellular HBV DNA levels
were measured by quantitative Southern blot hybridization.
11-((1H-imidazol-1-yl)methyl)-3-fluoro-9-methoxy-6H-
[1]benzothiopyrano[4,3-b]quinolin-10-ol 9a
To a solution of 1H-imidazole (50 mmol) and 36% HCl (50 mmol)
in 1,4-dioxane (30 mL) was added 7f (10 mmol). The reaction mix-
ture was further stirred at 808C for 3 h. After the reaction, the
resulting mixture was poured into water (100 mL), and then the
precipitate was collected by filtration. The crude product was
purified by flash column chromatography to obtain the desired
compound 9a (71%). m.p.: 1828C (dec); IR (KBr): 1248.3, 1384.0,
Cytotoxicity assay
Cytotoxicity induced by compounds 7–9 was also tested in
HepG2.2.15 cells. HepG2.2.15 cells were grown to confluence in
96-well flat-bottomed tissue culture plates and treated with the
test compounds (in 0.2 mL culture medium/well). Untreated con-
trol cultures were maintained on each 96-well plate. Toxicity
was determined by measuring neutral red-dye uptake, as deter-
mined from the absorbance at 510 nm relative to untreated
cells, at 24 h following day 9 of treatment. The IC50 and selected
index of the evaluated compounds and lamivudine were calcu-
lated, respectively.
1481.0, 1532.0, 1585.3, 2852.3, 3131.3, 3398.6 cm– 1 1H-NMR
;
(DMSO-d6, 300 MHz) d: 3.99 (s, 3H), 4.25 (s, 2H), 5.98 (s, 2H), 7.16–
7.23 (m, 1H), 7.31–7.35 (m, 1H), 7.44 (s, 1H), 7.53 (s, 1H), 7.67 (s,
1H), 8.12 (s, 1H), 8.61–8.63 (m, 1H), 9.12 (s, 1H); MS (ESI) m/z:
394.1 [M + 1+]. Anal. Calcd. for C21H16FN3O2S: C, 64.11; H, 4.10; F,
4.83; N, 10.68. Found: C, 63.99; H, 4.23; N, 10.55.
References
3-Fluoro-9-methoxy-11-((2-methyl-1H-imidazol-1-
yl)methyl)-6H-[1]benzothiopyrano[4,3-b]quinolin-10-ol 9b
Similarly to the procedure described for 9a, the title compound
was prepared starting from 2-methyl-1H-imidazole and 7f. 9b
was obtained as a yellow solid (67%). m.p.: 2158C (dec); IR (KBr):
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;
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(DMSO-d6, 300 MHz) d: 2.65 (s, 3H), 3.99 (s, 3H), 4.27 (s, 2H), 5.78
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1H), 7.43 (s, 1H), 8.13 (s, 1H), 8.51–8.53 (m, 1H); MS (ESI) m/z:
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10.31. Found: C, 64.70; H, 53; N, 10.29.
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consecutive daily doses of the test compounds and lamivudine
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described [10–12]. The medium was changed daily with fresh
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i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com