Discovery of novel 1,2,3,4-tetrahydrobenzo[4, 5]thieno[2, 3-c]pyridine derivatives as potent and selective CYP17 inhibitors

Article abstract of DOI:10.1016/j.ejmech.2017.03.037

The inhibition of CYP17 to block androgen biosynthesis is a well validated strategy for the treatment of prostate cancer. Herein we reported the design, synthesis and structure–activity relationship (SAR) study for a series of novel 1,2,3,4- tetrahydroben

Full text of DOI:10.1016/j.ejmech.2017.03.037

Accepted Manuscript
Discovery of novel 1,2,3,4-tetrahydrobenzo[4, 5]thieno[2, 3-c]pyridine derivatives as
potent and selective CYP17 inhibitors
Mingliang Wang, Yanjia Fang, Shoulai Gu, Fangfang Chen, Zhengjiang Zhu, Xun
Sun, Jidong Zhu
PII:
S0223-5234(17)30194-0
10.1016/j.ejmech.2017.03.037
EJMECH 9297
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 11 January 2017
Revised Date: 7 March 2017
Accepted Date: 19 March 2017
Please cite this article as: M. Wang, Y. Fang, S. Gu, F. Chen, Z. Zhu, X. Sun, J. Zhu, Discovery of novel
1,2,3,4-tetrahydrobenzo[4, 5]thieno[2, 3-c]pyridine derivatives as potent and selective CYP17 inhibitors,
European Journal of Medicinal Chemistry (2017), doi: 10.1016/j.ejmech.2017.03.037.
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Graphical abstract

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Discovery of novel 1,2,3,4-tetrahydrobenzo[4, 5]thieno[2, 3-c]pyridine derivatives
as potent and selective CYP17 inhibitors
a
b
b
b
b
Mingliang Wang, Yanjia Fang, Shoulai Gu, Fangfang Chen, Zhengjiang Zhu, Xun
a,c
b
Sun* and Jidong Zhu*
a
Department of Natural Products Chemistry, Fudan University, 826 Zhangheng Road,
Shanghai 201203, PR China.
b
Interdisciplinary Research Center on Biology and Chemistry, Chinese Academy of
Sciences, 345 Lingling Road, Shanghai 200032, PR China.
c
The Institutes of Integrative Medicine of Fudan University, 12 Middle Urumqi Road,
Shanghai 200040, PR China.
*
To whom correspondence should be addressed. Tel.: +86-21-51980003; Fax:
86-21-51980003. E-mail address: zhujd@sioc.ac.cn (J. Zhu), sunxunf@shmu.edu.cn
X. Sun).
+
(

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Abstract
The inhibition of CYP17 to block androgen biosynthesis is a well validated strategy
for the treatment of prostate cancer. Herein we reported the design, synthesis and
structure–activity relationship (SAR) study for a series of novel 1,2,3,4-
tetrahydrobenzo[4,5]thieno[2,3-c]pyridine derivatives. Some analogs demonstrated a
potent inhibition to both rat and human CYP17 protein and reduced testosterone
production in human H295R cell line. Some analogs also showed high selectivity
against other CYP enzymes such as 3A4, 1A2, 2C9, 2C19 and 2D6, which may limit
side effects due to drug-drug interactions. Among these analogs, the most potent
compound 9c showed 1.5 fold more potent against rat and human CYP17 protein than
that of abiraterone (IC = 16 nM and 20 nM vs. 25 nM and 36 nM respectively). In
5
0
NCI-H295R cells, the inhibitory effect of compound 9c on testosterone production
52 ± 2%) was also more potent than that of abiraterone (74 ± 15%) at the
(
concentration of 1 µM. Further, it was shown that 9c reduced plasma testosterone
level in a dose-dependent manner in Sprague-Dawley rats. Thus, analog 9c maybe a
potential agent used for the treatment of prostate cancer.
Keywords: Prostate cancer, androgens, CYP17, abiraterone, CYP3A4

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1
. Introduction
Prostate cancer is the most common malignancy in men and continues to be a major
cause of cancer deaths [1-3]. Prostate cancer patients in the early stages can be cured
with localized therapies, such as prostatectomy, radiation and cryotherapy [4].
However, men with recurrent or advanced-stage disease, particularly in metastatic
state, when treated with hormone therapy, drug resistance occurs rapidly. This leads
to a disease state known as castration-resistant prostate cancer (CRPC) [4-6]. Further,
traditional androgen deprivation therapies, such as using orchiectomy and GnRH
analogues, only eliminate androgen production in testes. The biosynthesis of androgen
inside adrenals and tumor cells remains to be not affected [7]. It is well known that
androgens produced by the tumor and/or the adrenal gland drive disease progression
in CRPC [8]. Thus, reduction or suppression of hormone levels inside adrenals and
cancer cells remains a key point in advanced stages of the disease. Therefore, total
blockage of the androgen biosynthesis by inhibiting 17α-hydroxylase-17,20-lyse
(CYP17) appears to be a superior alternative approach [9-12].
CYP17, expressed in the testes, adrenal glands and prostate cancer cells, is a
monooxygenase with a critical role in the synthesis of steroid hormones. This enzyme
catalyzes the conversion of 17α-hydroxypregnenolone and 17α-hydroxyprogesterone
into the weak androgens, dehydroepiandrosterone and androstenedione, respectively.
These weak androgens are subsequently converted into more potent androgens such
as testosterone and dihydrotestosterone in prostate cancer cells [9, 13]. The inhibition
of CYP17 could completely attenuate the production of androgens in testes, adrenals
as well as prostate cancer cells. Therefore, inhibitors of CYP17 are supposed to be
more effective for treating androgen-dependent prostate cancer, regardless of
androgen receptor mutations.
Several well-characterized CYP17 inhibitors were discovered for the treatment of
advanced prostate cancer (Fig.1). Among them, 1 (Ketoconazole), an antifungal agent
that inhibits CYP17 activity, has been used clinically in high dose for the treatment of
advanced prostate cancer [14]. However, Ketoconazole has been discontinued due to
its poor selectivity and severe hepatic toxicity [15]. Compound 2 (Abiraterone

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acetate), another approved drug targeting CYP17, exhibits significant beneficial
effects in CRPC patients [16]. However, its steroidal scaffold renders abiraterone a
promiscuous profile with affinities toward to other steroid receptors, raising the
cautions of its side effects. For example, it has been noted that abitaterone acts as a
moderate-to-potent inhibitor of several hepatic CYP enzymes including CYP1A2,
CYP2D6, CYP2C8, CYP2C9 and CYP3A4 [17]. Recently, steroidal CYP17 inhibitor
3
(TOK-001) [18], also acting as an androgen receptor antagonist, was terminated in
its phase III clinical trial due to the lack of clinical efficacy [19]. Thus, these potential
adverse effects of steroidal drugs triggered the efforts to develop nonsteroidal CYP17
inhibitors. These efforts have pushed several drug candidates into clinical study, such
as 4 (TAK-700) [20, 21], 5 (VT-464) [22, 23], 6 (YM-116) [24] and CFG920 [25]
(Fig. 1). Meanwhile, several other groups also have identified a few CYP17 inhibitors
as potential agents for the treatment of prostate carcinoma [26 -31].
Figure 1
Our group has previously synthesized series of metalloenzyme inhibitors [32, 33].
CYP17 enzyme, as one of metalloenzyme family members, has aroused our research
interest, especially when the X-ray structure of CYP17 was disclosed by DeVore and
Scott in 2012 [34]. Structural analysis of the reported CYP17 inhibitors reveals that
most of the compounds consist of two chemical components. One is the metal-binding
group that binds to the heme iron, and the second is the scaffold that binds to the
substrate pocket of CYP17. Based on this observation, we conducted a screen of
compounds from our in-house metalloenzyme inhibitor library and identified
compound 7 that could inhibit rat CYP17 lyase activity with IC50 of 228 nM
(
IC50 >10000 nM for CYP3A4). Our preliminary modeling study indicated that
compound 7 could fit nicely into the CYP17 binding pocket and maintain the key
interactions with the residues of CYP17. As shown in Fig. 2, the nitrogen of the
pyridine and the tetrahydro-β-carboline core formed a coordination bond and
hydrophobic interactions with heme group (Fe atom) and hydrophobic pocket (A113,

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F114, S106, A105, V236, L209, I206 and V482 residue), respectively. Since there is
unfilled space on the pyridine part in the active site cavity adjacent to V366, A367,
I371 and V483 residue, introducing substituent onto the pyridine ring may well fill
this space and enhance the potency (Fig. 2). These efforts led to the design and
synthesis compounds 8a-i and 9b-j and evaluated their CYP17 activity. Preliminary
selectivity for hepatic CYP enzymes including 3A4, 1A2, 2C9, 2C19 and 2D6 was
also tested for some selected compounds (see supporting document). Cellular activity
to inhibit testosterone secretion by CYP17 inhibitors was evaluated in the human
adrenal corticocarcinoma H295R cell line. Among these compounds, 9c showed the
best potency against both rat and human CYP17. Compound 9c was further examined
for its potency of reducing plasma testosterone concentration in rats. Molecular
modeling study by superposition of 9c into TOK-001 crystal structure confirmed that
the sulfur atom is more likely to bind to hydrophobic pocket than NH, and F and OH
group at the scaffold part, which could form hydrogen bond with N202 in the F helix.
Keeping these two features, compounds 9a and 9k-n were designed, synthesized and
evaluated their inhibitory activity against CYP17. This further modification resulted
9
m with a potent CYP17 inhibitory activity, though similar to that of 9c.
Figure 2
Figure 3
. Results and discussion
2
2
.1. Chemistry
Compounds 8a-e were prepared via two different synthetic routes illustrated in
Scheme 1. For the synthesis of 8a, the commercially available material
-(benzo[b]thiophen-3-yl)acetonitrile (10) was used as the starting material.
Compound 10 was converted to Boc-protected amine 11 by using NaBH /NiCl ·6H O
2
4
2
2
in the presence of (Boc) O in 48% yield. Intermediate 11 reacted with
2
paraformaldehyde catalyzed by TsOH to afford 12 via Pictet-Spengler reaction in 68%
yield. Removal of Boc group in 12 with TFA gave 20a which reacted with
3
-pyridinecarboxaldehyde to afford 8a via reductive amination in 62% yield (2 steps).
For the synthesis of 8b-e, commercially available 4-substituted benzenethiols 13b-e

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were used as the starting materials. Benzenethiols 13b-e reacted with ethyl
4
-chloroacetoacetate to afford 14b-e in 86-93% yields, followed by cyclization
catalyzed by polyphosphoric acid to give 3-substituted benzo[b]thiophenes 15b-e in
7-62% yields. Treatment of 15b-e with ammonia in methanol at room temperature
4
afforded the corresponding amides 16b-e in 72-88% yields. Then intermediates 16b-e
were reduced with borane in tetrahydrofuran to the corresponding amines 17b-e,
followed by reacting with ethyl chloroformate to obtain 18b-e in 83-91% yields.
Similar method to prepare 12 was employed here to convert 18b-e to 19b-e via
Pictet-Spengler reaction. After deprotection and reductive amination, analogs 8b-e
were prepared from 19b-e in 2 steps in 48-58% yields.
Scheme 1.
The syntheses of analogs 8f-l were accomplished by using 8d as the starting
material (Scheme 2). Analog 8f was obtained via Suzuki coupling of 8d with
methylboronic acid. Through Miyaura boration reaction, 8g was synthesized from 8d
in 64% yield, which was converted to 8h by using hydrogen peroxide under basic
condition in 54% yield. Compound 8d was transformed to 8i via palladium-catalyzed
coupling reaction in 72% yield. Hydrolysis cyano group in 8i afforded the
corresponding carboxylic acid 8j-1, which reacted with methylamine to give amide 8j
in 37% yield (2 steps). Compound 8k was synthesized from 8d with t-butyl carbamate
via Buchwald−Hartwig coupling reaction. The obtained 8k was further converted to
8
l by deprotection and acylation (69% yield).
Scheme 2.
Analogs 9a-n were synthesized by using compound 20b as the common starting
material shown in Scheme 3. Analog 9a was simply prepared by amide bond coupling
of 20b with nicotinic acid under HATU and DIPEA condition in 57% yield. For
analogs 9b and 9h-n, they were prepared by reductive amination of 20b with
corresponding aldehydes in 44-72% yields. Analogs 9c-f were obtained via Suzuki
coupling of 9b with the corresponding boronic acids in 54-64% yields. Finally,
hydrogenation of 9f with Pd/C in MeOH afforded 9g in 69% yield.

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Scheme 3.
2
2
.2. Biological results
.2.1. CYP17 Inhibitory Activity
Inhibition of human or rat CYP17 was determined by performing CYP17
biochemical assay following the procedure as previously described [35, 36]. Human
CYP17 gene was cloned and expressed in Adenoviral expression system in A549 cell
lines [37]. The purified cell membrane preparations were used as the source for
human CYP17 enzyme. For the rat CYP17 assay, we used rat testes microsomes as
the enzyme source [38]. The assay was run with 17α-hydroxyprogesterone as
substrate at concentration of 10 µM and NADPH as cofactor, separation of substrate
and product was accomplished by LCMS using UV detection.
Table 1
Table 2
Initially, we maintained the pyridin-3-ylmethyl group as a metal-binding part and
simply replaced with sulfur on 7 instead of nitrogen, the resulting compound 8a was
4
-fold more potent (IC = 54.9 nM) than its corresponding N analog 7 (IC = 228.5
50 50
nM) for rat CYP17 (Table 1). Further modification on phenyl ring by incorporating a
fluoro at R position, compound 8b enhanced two fold potency (IC = 28.1 nM)
1
50
compared with 8a, which was almost as potent as ABT (IC = 24.7 nM). When fluoro
5
0
was replaced with chloro (8c) or bromo (8d) to increase the substituent volumn, the
potency for rat CYP17 was tremendously decreased (16 to 18 fold). Introducing
electro-donating groups at this position, such as methoxy (8e) or methyl (8f) group,
did not improve the potency, especially 8e totally abolished the potency. Other
modifications also did not show any benefit, either only having moderate activity (8g
and 8i) or totally losing potency (8j-l). Interestingly, the hydroxyl substituted analog
8
h was more potent than ABT with IC value of 20.9 nM. This consisted with our
50
molecular modeling study that F and OH group at the scaffold part may be able to
form hydrogen bond with N202 in the F helix. Although compound 8h showed
slightly improved activity, the hydroxyl phenyl group made this compound not very
stable, especially in solution. Therefore, we selected compound 8b as a lead for

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further optimizing the heteroaryl substituent on the metal-binding moiety.
The results for SAR study of metal-binding region on nitrogen were shown on
Table 2. Acylated compound 9a lost potency for CYP17, indicating that the
conformation between the metal-binding region and metal binding moiety was
favored to be linked with a methylene bridge. Thus, methylene linker was kept for
further SAR study. Compound 9b with an ortho substituted bromo kept the potency,
though 3-fold decreased compared with 8b. When replaced bromo with methyl group,
compound 9c showed the most potent inhibitory activity for rat CYP17. Compund 9e
with a cyclopropyl substituent remained a good activity; however, compounds 9f, 9g
and 9d decreased the potency or even lost potency when futher increased the
substituent volumn. When shifted the substituent from ortho- to meta-position,
compounds 9h-j still kept good to moderate activity, especially 9i only lost 2-fold
potency compared with 9c. Replacement of 3-pyridine with imidazole ring, analog
9
m also showed very good potency (IC = 29.8 nM), though both pyrimidine and
50
isoquinoline replacement did not show better activity. Interestly, compound 9l, which
was a 4-pyridine instead of 3-pyridine, totally lost its potency.
Selected compounds (8b, 8h, 9c, 9h, 9i and 9m) along with ABT were evaluated
for inhibitory activity for human recombinant C17,20-lyase. Similar trend to rat CYP17,
these compounds showed potent inhibitory activity for human CYP17 with IC50
values of 20–45 nM. Especially, 9c exhibited 1.5 fold more potent than reference
compound ABT (IC = 35.8 nM) in this assay. Further, all these selected compounds
5
0
demonstrated great enzyme selectivity against human CYP3A4 (Table 3).
2
.2.2. Inhibition of human CYP3A4 and other hepatic CYP enzymes
According to the activity data of rat CYP17 in Table 1 and 2, the most promising
compounds (8b, 8h, 9c, 9h, 9i and 9m) were tested for inhibition of human CYP17,
CYP3A4 and other hepatic CYP enzymes. Overall, these compounds exhibited
similar activity trend toward to both rat and human CYP17. These compounds
showed very weak inhibition of CYP3A4 (IC50 > 5000 nM) except imidazol
substituted compound 9m which showed moderate inhibitory activity (IC = 680 nM).
5
0
The most potent CYP17 inhibitor 9c exhibited IC value of 8.5 µM against CYP3A4,
5
0

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showing a better selectivity profile than ABT (IC = 2.7 µM). Compound 9c also
50
showed no or very weak inhibition against CYP1A2 (16.3 % at 1 µM), CYP2C9 (0 %
at 1 µM), CYP2C19 (11.7 % at 1 µM) and CYP2D6 (12.0 % at 1 µM) (see
supplementary material).
2
.2.3. Inhibitory effects of selected compounds in testosterone production in
NCI-H295R cells.
Table 4
Compounds (8b, 8h, 9c, 9h, 9i and 9m) were also tested their inhibition for
testosterone production in NCI-H295R cells that were derived from an adrenocortical
carcinoma and commonly studied for autonomous aldosterone secretion. At the
concentration of 1 µM, ABT and compound 9c inhibited testosterone production to 74
±
15% and 52 ± 2% respectively (P < 0.05 comparing with control), suggesting that
the inhibitory effect of compound 9c on testosterone production was more potent than
that of ABT (Table 4).
2
.2.4. Compound 9c and ABT were evaluated for their inhibitory effects on steroid
biosynthesis in male rats.
Table 5
Following a single oral dose, compound 9c significantly decreased serum
testosterone concentration in a dose-dependent manner. At dose 10 mg/kg, serum
testosterone concentration was low to the detectable quantitative limit after 2 h of the
post-dose (Table 5).
2
.3 Molecular modeling studies.
To better understand the interactions between the newly synthesized compounds
and CYP17, the potential binding mode of potent compound 9c was investigated
using the CDOCKER program in Discovery Studio 3.0 software. The published
crystal structure of ABT and TOK-001 bound within the active site cavity of CYP17
(PDB ID: 3RUK) served as a useful template for generating proposed binding modes.
The docking pose of compound 9c overlaps well with TOK-001. Compound 9c forms
a coordinate (dative) bond with the heme iron through the nitrogen of the
4
-methylpyridine, positioning the tricyclic core above the heme plane at an angle of

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~60 degree. The piperidinethiophene ring lies flat against the I helix and forms several
hydrophobic and Van de Walls interactions with G301 and A302. As a result, the
fluorobenzyl ring is oriented toward to F and G helices. Unlike TOK-001, there is no
polar interaction, i.e. hydrogen-bond interactions observed in the docking model.
However, substitutions at the ortho-position of the fluorobenzyl moiety could provide
hydrogen-bond interactions with the side-chain of N202 and potentially improve the
potency.
Figure 4A.
Figure 4B.
3
. Conclusion
In summary, we have designed and synthesized a series of 1,2,3,4-tetrahydrobenzo
[
4,5]thieno[2,3-c]pyridine derivatives. Among them, analogs 8b, 8h, 9c, 9h, 9i and
m, showed excellent CYP17 activities with IC values equal or better than marked
9
5
0
drug abiraterone both in rat and human enzyme assay. In addition, the most promising
compound 9c showed no or very weak inhibition on other human hepatic CYP
enzymes. In addition, compound 9c significantly reduced testosterone level both in
NCI-H295R cells and serum levels in male rats. Further, molecular docking
simulation of 9c into the CYP17 active site was performed. The result demonstrated
that 9c occupies the CYP17 active site, forming interactions with the main amino acid
residues. Thus, this type of compounds has the potential to be leads for developing
novel CYP17 inhibitors. Further structural optimization and antitumor mechanism
study of these derivatives are in progress.
4
4
4
. Experimental
.1 Chemistry
.1.1. General considerations
All starting materials and reagents were either obtained from commercial suppliers
or prepared according to literature reported procedures. All purchased chemicals and
solvents were used without further purification unless otherwise noted. Flash

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chromatography was performed using silica gel (300−400 mesh). All reactions were
monitored by thin-layer chromatography (TLC), using silica gel plates with
fluorescence F254 and visualized under UV light. Melting points (mp) were
determined using an X-4 microscope melting point apparatus and were uncorrected.
1
NMR spectra were obtained on a Bruker AV II-400 MHz spectrometer ( H NMR at
13
19
4
00 MHz, C NMR at 100 MHz, and F NMR at 375 MHz). Chemicals shifts (δ)
were reported in parts per million, coupling constants (J) values were in hertz, and the
splitting patterns were abbreviated as follows: s for singlet; d for doublet; t for triplet;
q for quartet; and m for multiplet. Low resolution electrospray ionization (ESI) mass
spectra were recorded on an Agilent 1200 HPLC-MSD mass spectrometer and high
resolution ESI-MS on a Thermo Fisher Scientific LTQ FT Ultra. EI-MS were
performed on an Agilent 5973N instrument for and a Waters Micromass GCT Premier
instrument for High-resolution mass. All tested compounds were purified to ≥ 95%
purity as determined by high performance liquid chromatography (HPLC).
4
.1.2.1. General method A for reductive amination
To a solution of amine (1.0 equiv) in 1,2-dichloroethane (0.1 M) were added
aldehyde (1.2 equiv) and acetic acid (0.5 mL), the reaction mixture stirred at rt for 10
mins, followed the addition of sodium triacetoxyborohydride (2.0 equiv). The reaction
was stirred at rt under nitrogen for 18 h and concentrated. Sat. NaHCO (30 mL) was
3
added and extracted with dichloromethane (20 mL x 3) and the combined organic
layers were dried over anhydrous Na SO , filtered and evaporated under reduced
2
4
pressure. The crude residue was purified by flash chromatography on silica gel eluting
with 0-10% methanol/dichloromethane to give the desired product.
4
.1.2.2. General method B for Suzuki coupling
To a solution of the corresponding bromo-derivative (1.0 equiv) in 1,4-Dioxane (10
mL/mmol), an aqueous Na CO solution (3.0 equiv) and the corresponding boronic
2
3
acid (1.5 equiv) were added. The mixture was deoxygenated under reduced pressure
and flushed with nitrogen. After having repeated this cycle three times,
Pd(dppf)Cl ·CH Cl (0.05 equiv) was added. The resulting suspension was heated
2
2
2

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under 100 °C for 8h. After cooling down, ethyl acetate (30 mL) and water (20 mL)
were added. The organic layer was separated and the water phase was extracted with
ethyl acetate (20 mL x 2). The combined organic layers were dried over Na SO ,
2
4
concentrated in vacuo, and purified by column chromatography eluting with 0-10%
methanol/dichloromethane to give the desired product.
4
.1.3.1. 2-(Pyridin-3-ylmethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (7)
Following the general experimental procedure A, compound 7 was obtained as an
off-white solid (280 mg, 71%) from 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (258
mg, 1.5 mmol) and 3-pyridinecarboxaldehyde (193 mg, 169 µL, 1.8 mmol). Mp:
o
1
1
71.2 – 173.0 C; H NMR (400 MHz, DMSO-d ) δ 10.85 (s, 1H), 8.57 (s, 1H), 8.50
6
(d, J = 4.8 Hz, 1H), 7.79 (d, J = 7.6 Hz, 1H), 7.40 – 7.34 (m, 2H), 7.26 (d, J = 8.0 Hz,
1
H), 7.01 (t, J = 7.4 Hz, 1H), 6.93 (t, J = 7.4 Hz, 1H), 3.76 (s, 2H), 3.58 (s, 2H), 2.80
1
3
(
t, J = 5.6 Hz, 2H), 2.69 (t, J = 5.0 Hz, 2H); C NMR (100 MHz, DMSO-d ) δ 150.0,
6
1
4
48.4, 136.5, 134.1, 132.6, 126.7, 123.5, 120.3, 118.3, 117.4, 110.9, 106.3, 58.4, 50.5,
-1
9.8, 21.1; IR (KBr, ν/cm ): 3062, 2854, 1577, 1369, 1155, 1029, 843, 769; ESI-MS
+
+
m/z: 264.1 [M+H] ; HRMS (ESI-TOF) calcd for C H N [M+H] : 264.1495, found:
17
18
3
2
64.1495.
.1.3.2. 2-(Pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]pyridine (8
4
a)
Following the general experimental procedure A, compound 8a was obtained as an
off-white solid (204 mg, 73%) from compound 20a (190 mg, 1.0 mmol) and
o
1
3
-pyridinecarboxaldehyde (129 mg, 1.2 mmol). Mp: 61.2 – 62.9 C; H NMR (400
MHz, DMSO-d ) δ 8.83 (s, 1H), 8.76 (d, J = 4.4 Hz, 1H), 8.15 (d, J = 7.6 Hz, 1H),
6
7
.99 (d, J = 7.6 Hz, 1H), 7.76 (d, J = 7.6 Hz, 1H),7.68 – 7.65 (m, 1H), 7.47 – 7.39 (m,
1
3
2
H), 4.62 (s, 2H), 4.56 (s, 2H), 3.68 (s, 2H), 3.15 (s, 2H); C NMR (100 MHz,
DMSO-d ) δ 158.6, 158.2, 150.6, 149.3, 140.7, 138.3, 137.3, 127.1, 125.1, 124.7,
6
-
1
1
1
24.5, 122.8, 121.4, 55.6, 49.6, 48.6, 20.9; IR (KBr, ν/cm ): 3073, 2531, 1676, 1478,
+
193, 1128, 799, 722; ESI-MS m/z: 281.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H N S [M+H] : 281.1107, found: 281.1106.
17
17
2

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4
.1.3.3. 6-Fluoro-2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]py
ridine (8b)
Following the general experimental procedure A, compound 8c was obtained as an
off-white solid (110 mg, 73.4%) from compound 20b (104 mg, 0.50 mmol) and
o
1
3
-pyridinecarboxaldehyde (64 mg, 0.60 mmol). Mp: 57.3 – 59.1 C; H NMR (400
MHz, CDCl ) δ 8.61 (d, J = 1.6 Hz, 1H), 8.59 – 8.57 (m, 2H), 7.89 (d, J = 8.0 Hz, 1H),
3
7
3
1
1
1
.70 – 7.67 (m, 1H), 7.35 – 7.32 (m, 1H), 7.26 – 7.23 (m, 1H), 7.08 – 7.03 (m, 1H),
1
3
.87 (s, 2H), 3.85 (s, 2H), 3.03 (s, 2H), 2.88 (s, 2H); C NMR (100 MHz, CDCl ) δ
3
61.1 (d, J = 240.3 Hz), 150.3, 149.2, 140.1 (d, J = 9.0 Hz), 137.4, 135.7, 134.0,
32.8, 127.9 (d, J = 4.2 Hz), 123.9, 123.7 (d, J = 9.3 Hz), 111.8 (d, J = 24.9 Hz),
1
9
06.7 (d, J = 22.9 Hz), 58.6, 52.0, 49.6, 23.4; F NMR (375 MHz, CDCl ) δ −118.46
3
-1
to −118.52 (m, 1F); IR (KBr, ν/cm ): 2909, 2816, 1654, 1599, 1429, 1177, 1122, 843,
+
+
7
68; ESI-MS m/z: 299.0 [M+H] ; HRMS (ESI-TOF) calcd for C H FN S [M+H] :
17 16 2
2
99.1013, found: 299.1014.
.1.3.4. 6-Chloro-2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]
4
pyridine (8c)
Following the general experimental procedure A, compound 8c was obtained as an
off-white solid (63 mg, 66.8%) from compound 20c (67 mg, 0.30 mmol) and
o
1
3
-pyridinecarboxaldehyde (39 mg, 0.36 mmol). Mp: 230.2 – 231.9 C; H NMR (400
MHz, DMSO-d ) δ 9.18 (s, 1H), 8.96 (d, J = 5.2 Hz, 1H), 8.81 (d, J = 8.0 Hz, 1H),
6
8
.05 – 8.02 (m, 2H), 7.87 (d, J = 7.6 Hz, 1H), 7.44 – 7.42 (m, 1H), 4.76 (s, 2H), 4.55
1
3
(
s, 2H), 3.70 (s, 2H), 3.21 (s, 2H); C NMR (100 MHz, DMSO-d ) δ 146.4, 146.3,
6
1
4
6
3
44.5, 138.8, 136.8, 130.2, 129.9, 128.7, 126.8, 126.3, 125.0, 124.5, 121.1, 54.4, 48.8,
-1
8.4, 20.6; IR (KBr, ν/cm ): 3413, 3035, 2553, 2109, 1637, 1429, 1385, 1067, 848,
+
+
73; ESI-MS m/z: 315.0 [M+H] ; HRMS (ESI-TOF) calcd for C H ClN S [M+H] :
1
7
16
2
15.0717, found: 315.0719.
.1.3.5. 6-Bromo-2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]py
4
ridine (8d)
Following the general experimental procedure A, compound 8d was obtained as an

ACCEPTED MANUSCRIPT
off-white solid (524 mg, 72.9%) from compound 20d (536 mg, 2.0 mmol) and
o
1
3
-pyridinecarboxaldehyde (257 mg, 2.4 mmol). Mp: 113.2 – 114.9 C; H NMR (400
MHz, CDCl ) δ 8.61 (s, 1H), 8.57 – 8.56 (m, 1H), 7.83 (d, J = 8.0 Hz, 1H), 7.71 (d, J
3
=
1.6 Hz, 1H), 7.62 (d, J = 8.0 Hz, 1H), 7.40 – 7.30 (m, 2H), 3.83 (s, 2H), 3.81 (s, 2H),
1
3
2
1
.98 (t, J = 5.8 Hz, 2H), 2.86 (t, J = 5.6 Hz, 2H); C NMR (100 MHz, CDCl ) δ
3
50.3, 149.1, 140.7, 137.4, 137.3, 135.5, 133.1, 127.6, 127.2, 123.9, 123.8, 123.7,
-1
1
18.4, 58.8, 52.0, 49.6, 23.5; IR (KBr, ν/cm ): 2903, 2821, 1577, 1424, 1330, 1133,
+
1
062, 843, 799; ESI-MS m/z: 358.9/ 360.9 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H BrN S [M+H] : 359.0212, found: 359.0211.
17
16
2
4
.1.3.6. 6-Methoxy-2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]
pyridine (8e)
Following the general experimental procedure A, compound 8e was obtained as
white-off solid (64.5 mg, 69.3%) from compound 6a (65.8 mg, 0.30 mmol) and
o
1
3
-pyridinecarboxaldehyde (38.5 mg, 0.36 mmol). Mp: 211.7 – 212.3 C; H NMR
(
400 MHz, CDCl ) δ 9.17 (s, 1H), 8.94 (d, J = 5.2 Hz, 1H), 8.77 (d, J = 7.6 Hz, 1H),
3
8
.02 – 7.99 (m, 1H), 7.85 (d, J = 8.8 Hz, 1H), 7.26 (d, J = 2.0 Hz, 1H), 7.04 – 7.01 (m,
1
3
1
H), 4.75 (s, 2H), 4.51 (s, 2H), 3.84 (s, 3 H), 3.53 (s, 2H), 3.18 (s, 2H); C NMR
(
100 MHz, CDCl ) δ 157.5, 146.6, 146.0, 144.9, 138.6, 130.2, 128.8, 128.5, 126.9,
3
-1
1
26.2, 123.5, 114.6, 104.2, 55.5, 54.5, 48.9, 48.6, 20.8; IR (KBr, ν/cm ): 3024, 2509,
2
317, 2087, 1988, 1610, 1429, 1216, 1150, 1013, 826, 788; ESI-MS m/z: 311.0
+
+
[
M+H] ; HRMS (ESI-TOF) calcd for C H N OS [M+H] : 311.1213, found:
18 19 2
3
11.1212.
.1.3.7. 6-Methyl-2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]
4
pyridine (8f)
Following the general experimental procedure B, compound 8f was obtained as a
light yellow oil (50 mg, 56.8%) from 8d (108 mg, 0.30 mmol) and methylboronic acid
1
(
27 mg, 0.45 mmol). H NMR (400 MHz, CDCl ) δ 8.61 (d, J = 1.2 Hz, 1H), 8.56 –
3
8
.54 (m, 1H), 8.61 (d, J = 1.2 Hz, 1H), 7.77 (d, J = 7.6 Hz, 1H), 7.65 (d, J = 8.0 Hz,
H), 7.37 – 7.28 (m, 2H), 7.12 (d, J = 8.0 Hz, 1H), 3.78 (s, 2H), 3.77 (s, 2H), 2.93 (t,
1

ACCEPTED MANUSCRIPT
1
3
J = 5.6 Hz, 2 H), 2.84 (t, J = 5.6 Hz, 2 H), 2.46 (s, 2H); C NMR (100 MHz, CDCl )
3
δ 150.4, 148.9, 139.4, 137.0, 135.8, 134.2, 134.0, 133.9, 127.9, 125.7, 123.7, 122.2,
-
1
1
1
20.9, 59.0, 52.4, 49.8, 23.9, 21.6; IR (KBr, ν/cm ): 2923, 2456, 1578, 1423, 1302,
+
132, 1071, 847, 786; ESI-MS m/z: 295.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H N S [M+H] : 295.1263, found: 295.1264.
18
19
2
4
4
.1.3.8. 2-(Pyridin-3-ylmethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,2,3,
-tetrahydrobenzo[4,5]thieno[2,3-c]pyridine (8g)
A suspension of 8d (359 mg, 1.0 mmol), bis(pinacolato)diboron (381 mg, 1.5 mmol)
and KOAc (294 mg, 3.0 mmol) in DMF (4.0 mL) was added Pd(dppf) Cl (37 mg,
2
2
0
.05 mmol). The resulting reaction mixture was stirred at 100 °C for 3 h. After
cooling to rt, the mixture was diluted ethyl acetate (50 mL) and water (20 mL). The
organic layer was separated and the aqueous layer was extracted three times with
ethyl acetate. The combined organic layers were dried over Na SO , filtered, and
2
4
concentrated under a reduced pressure. The residue was then purified by silica gel
column chromatography eluting with 0-5% MeOH/DCM to give 8g (258 mg, 63.5%)
o
1
as AN OFF-white solid. Mp: 128.7 – 130.2 C; H NMR (400 MHz, CDCl ) δ 8.60 (d,
3
J = 1.6 Hz, 1H), 8.55 – 8.54 (m, 1H), 8.04 (s, 1H), 7.77 – 7.70 (m, 3H), 7.31 – 7.28
1
3
(
m, 1H), 3.78 (s, 2H), 3.77 (s, 2H), 2.94 – 2.87 (m, 4H), 1.37 (s, 12H); C NMR (100
MHz, CDCl ) δ 150.4, 148.9, 142.0, 138.6, 137.0, 133.8, 133.7, 129.9, 128.6, 127.6,
3
-
1
1
1
23.7, 122.0, 84.0, 75.2, 59.1, 52.3, 49.8, 25.0, 24.0; IR (KBr, ν/cm ): 2969, 2909,
+
599, 1451, 1341, 1145, 1089, 821; ESI-MS m/z: 407.1 [M+H] ; HRMS (ESI-TOF)
+
calcd for C H N O S [M+H] : 407.1959, found: 407.1957.
2
3
28
2
2
4
.1.3.9. 2-(Pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]pyridin-6-o
l (8h)
To a solution of 8g (204 mg, 0.50 mmol) and NaOH (40 mg, 1.0 mmol) in
THF/MeOH (1/1, 18 mL) was added 30% hydrogen peroxide (0.2 mL) at 0 °C. The
reaction mixture was allowed to warm to rt and stirred for 2 h. After quenched with
water (20 mL), the resulting mixture was extracted with ethyl acetate (20 mL x 2).
The organic layer was washed with brine (20 mL), dried over anhydrous Na SO , and
2
4

ACCEPTED MANUSCRIPT
then concentrated under a reduced pressure. The residue was then purified by silica
gel column chromatography eluting with 0-5% MeOH/DCM to give 8h (80 mg,
o
1
5
8
8
3
3.6%) as an off-white solid. Mp: 207.5 – 208.3 C; H NMR (400 MHz, CDCl ) δ
3
.55 (d, J = 1.2 Hz, 1H), 8.49 – 8.48 (m, 1H), 7.78 (d, J = 8.0 Hz, 1H), 7.63 (d, J =
.4 Hz, 1H), 7.38 (t, J = 5.6 Hz, 1H), 6.94 (d, J = 2.0 Hz, 1H), 6.81 – 6.79 (m, 1H),
1
3
.75 (s, 2H), 3.66 (s, 2H), 2.80 (t, J = 5.6 Hz, 2H), 2.69 (t, J = 5.2 Hz, 2H); C NMR
(
100 MHz, CDCl ) δ 155.1, 150.1, 148.5, 140.1, 136.7, 134.9, 133.9, 128.2, 127.6,
3
-1
1
23.7, 123.2, 114.1, 106.0, 57.9, 51.7, 49.0, 23.4; IR (KBr, ν/cm ): 3456, 2974, 2834,
+
1
599, 1456, 1226, 1121, 1016, 887; ESI-MS m/z: 297.0 [M+H] ; HRMS (ESI-TOF)
+
calcd for C H N OS [M+H] : 297.1056, found: 297.1055.
1
7
17
2
4
.1.3.10. 2-(Pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]pyridine-6
-carbonitrile (8i)
A mixture of compound 8d (450 mg, 1.25 mmol), zinc cyanide (176 mg, 1.50
mmol), and tetrakis(triphenylphosphine)palladium (0) (145 mg, 0.125 mmol) in DMF
10 mL) was stirred at 100 °C for 6 h under a nitrogen atmosphere. After cooling
(
down, it was poured onto aq. NaHCO solution (30 mL). After extracted with ethyl
3
acetate (20 mL x 2), the combined organic layers were washed with brine, dried over
Na SO and evaporated under vacuum. The residue was then purified by silica gel
2
4
column chromatography eluting with 0-5% MeOH/DCM to give 8i (274 mg, 71.8%)
o
1
as an off-white solid. Mp: 131.7 – 132.9 C; H NMR (400 MHz, CDCl ) δ 8.61(s,
3
1
1
=
H), 8.56 (d, J = 3.6 Hz, 1H), 7.88 – 7.78 (m, 3H), 7.51 (dd, J = 8.4 Hz, J = 1.6 Hz,
H), 7.33 – 7.30 (m, 1H), 3.82 (s, 2H), 3.80 (s, 2H), 2.98 (t, J = 5.6 Hz, 2H), 2.90 (t, J
13
5.2 Hz, 2H); C NMR (100 MHz, CDCl ) δ 154.9, 152.3, 150.4, 149.1, 143.1,
3
1
39.0, 137.0, 133.4, 128.3, 126.3, 125.1, 123.8, 123.5, 119.7, 107.9, 59.0, 52.1, 49.5,
-1
2
3.7; IR (KBr, ν/cm ): 2956, 2225, 1694, 1570, 1411, 1126, 1012, 812, 779; ESI-MS
+
+
m/z: 306.0[M+H] ; HRMS (ESI-TOF) calcd for C H N S [M+H] : 306.1059, found:
18
16
3
3
06.1059.
.1.3.11. N-Methyl-2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]
4
pyridine-6-carboxamide (8j)

ACCEPTED MANUSCRIPT
To a solution of 8i (210 mg, 0.68 mmol) in ethanol (5 mL) and water (5 mL) was
added sodium hydroxide potassium (220 mg, 5.51 mmol). The resulting mixture was
stirred under nitrogen at reflux for 12 hours and then evaporated in vacuo. The residue
was dissolved in ethyl acetate (30 mL) and washed with 2M aqueous hydrogen
chloride solution (10 mL). The organic extracts were dried over anhydrous Na SO
2
4
and evaporated in vacuo to afford crude 8j-1 which was used directly for the next step.
Compound 8j-1 was dissolved in DMF (6 mL), then methylamine hydrochloride (210
mg, 1.36 mmol), HATU (775.6 mg, 2.04 mmol) and DIPEA (0.71 mL, 4.08 mmol)
were added at 0 °C. The reaction mixture was allowed to warm to rt and stirred for 12
h. After quenched with water (20 mL), the resulting mixture was extracted with ethyl
acetate (15 mL x 2). The organic layer was washed with brine, dried over anhydrous
Na SO , and concentrated under a reduced pressure. The residue was then purified by
2
4
silica gel column chromatography eluting with 0-10% MeOH/DCM to give 8j (84 mg,
o
1
3
6.5%, two steps) as an off-white solid. Mp: 175.7 – 177.2 C; H NMR (400 MHz,
DMSO-d ) δ 8.58 (s, 1H), 8.52 (d, J = 3.6 Hz, 1H), 8.02 (s, 1H), 7.75 – 7.61 (m, 3H),
6
7
.29 – 7.26 (m, 1H), 6.65 (d, J = 3.6 Hz, 1H), 3.75 (s, 2H), 3.73 (s, 2H), 3.01 (d, J =
1
3
4
.8 Hz, 3H), 2.88 (t, J = 5.6 Hz, 2H), 2.81 (t, J = 5.2 Hz, 2H); C NMR (100 MHz,
DMSO-d ) δ 168.7, 150.3, 149.0, 141.6, 139.0, 136.9, 135.6, 133.7, 130.9, 128.7,
6
-
1
1
2
23.7, 122.5, 122.1, 119.8, 59.1, 52.2, 49.7, 27.0, 23.8; IR (KBr, ν/cm ): 3325, 2909,
+
805, 1649, 1539, 1440, 1308, 1134, 1117, 1023, 812; ESI-MS m/z: 338.0 [M+H] ;
+
HRMS (ESI-TOF) calcd for C H N OS [M+H] : 338.1322, found: 338.1323.
1
9
20
3
4
.1.3.12. Tert-butyl(2-(pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]
pyridin-6-yl)carbamate (8k)
To a round bottom flask under dry nitrogen were added Pd (dba) (91.5 mg, 0.1
2
3
mmol), Xantphos (174 mg, 0.30 mmol), 8d (359 mg, 1.0 mmol), t-butyl carbamate
176 mg, 1.5 mmol), cesium carbonate (652 mg, 2.0 mmol) and 1,4-dioxane (15 mL).
(
After degass three times, the mixture was stirred at 100 °C under dry nitrogen for 6 h.
The reaction mixture was cooled to rt, diluted with water (20 mL) and extracted with
ethyl acetate (15 mL x 3). The combined extracts were washed with brine, dried over

ACCEPTED MANUSCRIPT
sodium sulfate, filtered and concentrated under reduced pressure. The crude mixture
was purified by silica gel chromatography eluting with 0-10% MeOH/DCM to afford
o
1
8
k (247 mg, 62.5%) as an off-white solid. Mp: 181.7 – 182.5 C; H NMR (400 MHz,
CDCl ) δ 8.61 (s, 1H), 8.55 (d, J = 4.4 Hz, 1H), 7.80 – 7.58 (m, 2H), 7.32 – 7.28 (m,
3
1
H), 6.60 (s, 1H), 3.79 (s, 2H), 3.77 (s, 2H), 2.95 (t, J = 5.6 Hz, 2H), 2.87 (t, J = 5.2
1
3
Hz, 2H), 1.53 (s, 9H); C NMR (100 MHz, CDCl ) δ 153.1, 150.5, 149.1, 139.8,
3
1
4
1
37.0, 135.5, 135.0, 133.5, 133.3, 128.2, 123.7, 122.8, 116.3, 110.4, 80.7, 58.9, 52.3,
-1
9.8, 28.5, 23.8; IR (KBr, ν/cm ): 3227, 3080, 2821, 1719, 1572, 1456, 1358, 1248,
+
156, 1029, 792; ESI-MS m/z: 396.1 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H N O S [M+H] : 396.1740, found: 396.1740.
22
26
3
2
4
.1.3.13. N-(2-(Pyridin-3-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]pyridin
-6-yl)acetamide (8l)
To the solution of 8k (138.5 mg, 0.35 mmol) in DCM (5 mL) was added
trifluoracetic acid (1 mL) at 0 °C. The reaction mixture was allowed to warm to room
temperature and stirred for 2 h. After the solvent was removed under reduced pressure,
the residue was dissolved in DCM (5 mL ). To this solution, DIPEA (0.24 mL, 1.38
mmol) and acetic anhydride (0.13 mL, 1.38 mmol) were added at 0 °C. The reaction
mixture was allowed to warm to room temperature and stirred for 12 h, then sat.
NaHCO was added (20 mL). After extracted with CH Cl (15 mL x 3), the combined
3
2
2
organics were dried over anhydrous Na SO , filtered and concentrated in vacuo. The
2
4
residue was purified by silica gel column chromatography eluting with 5%
o
MeOH/DCM to give 8l as an off-white solid (81 mg, 68.7%). Mp: 168.6 – 169.9 C;
1
H NMR (400 MHz, CDCl ) δ 8.61 (s, 1H), 8.55 (d, J = 3.6 Hz, 1H), 7.90 (s, 1H),
3
7
3
9
1
.76 (d, J = 7.6 Hz, 1H), 7.66 (d, J = 8.4 Hz, 1H), 7.48 (s, 1H), 7.31 – 7.28 (m, 2H),
.77 (s, 2H), 3.75 (s, 2H), 2.91 (t, J = 5.6 Hz, 2H), 2.82 (t, J = 5.2 Hz, 2H), 2.20 (s,
1
3
H); C NMR (100 MHz, CDCl ) δ 168.5, 150.5, 149.0, 139.7, 136.9, 135.4, 134.9,
3
34.5, 133.8, 128.3, 123.7, 122.8, 117.2, 112.2, 59.1, 52.4, 49.9, 24.8, 23.9; IR (KBr,
-1
ν/cm ): 2953, 2761, 1676, 1533, 1456, 1330, 1145, 1034, 812; ESI-MS m/z: 338.0
+
+
[
M+H] ; HRMS (ESI-TOF) calcd for C H N OS [M+H] : 338.1322, found:
19 20 3

ACCEPTED MANUSCRIPT
3
38.1323.
.1.3.14. (6-Fluoro-3,4-dihydrobenzo[4,5]thieno[2,3-c]pyridin-2(1H)-yl)(pyridin-3-y
4
l)methanone (9a)
To the solution of 20b (62 mg, 0.30 mmol) and nicotinic acid (45 mg, 0.36 mmol)
in DMF (5 mL) were added HATU (229 mg, 0.60 mmol) and DIPEA (0.16 mL, 0.90
mmol) at 0 °C. The reaction mixture was allowed to warm to rt and stirred for 12 h.
After quenched with water (20 mL) and extracted with ethyl acetate (15 mL x 3), the
organic layers were washed with brine (15 mL), dried over anhydrous Na SO , and
2
4
concentrated under a reduced pressure. The residue was then purified by silica gel
column chromatography eluting with 0-10% MeOH/DCM to give 9a (53 mg, 56.7%)
o
1
as an off-white solid. Mp: 159.7 – 161.1 C; H NMR (400 MHz, CDCl ) δ 8.76 –
3
8
.72 (m, 2H), 7.83 (d, J = 6.8 Hz, 1H), 7.72 (s, 1H), 7.46 – 7.20 (m, 2H), 7.11 – 7.07
1
3
(
m, 1H), 5.04 – 3.80 (m, 4H), 2.95 – 2.83 (m, 2H); C NMR (100 MHz, CDCl ) δ
3
1
68.4, 161.2 (d, J = 241.0 Hz), 151.4, 147.9, 139.7, 138.4, 135.1, 134.0, 131.7, 123.9,
1
9
1
23.8, 113.2 (d, J = 23.4 Hz), 106.8 (d, J = 23.7 Hz), 45.0, 42.8, 24.9; F NMR (375
-1
MHz, CDCl ) δ −117.83 to −118.06 (m, 1F); IR (KBr, ν/cm ): 2936, 1637, 1572,
3
+
1
429, 1256, 1117, 835; ESI-MS m/z: 313.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H FN OS [M+H] : 313.0805, found: 313.0805.
17
14
2
4
.1.3.15. 2-[(4-Bromopyridin-3-yl)methyl]-6-fluoro-1,2,3,4-tetrahydrobenzo[4,5]thie
no[2,3-c]-pyridine (9b)
Following the general experimental procedure A, compound 9b was obtained as an
off-white solid (517 mg, 68.5%) from 20b (415 mg, 2.0 mmol) and
o
1
4
-bromonicotinaldehyde (447 mg, 2.4 mmol). Mp: 121.8 – 123.1 C; H NMR (400
MHz, CDCl ) δ 8.66 (s, 1H), 8.33 (d, J = 5.2 Hz, 1H), 7.70 – 7.67 (m, 1H), 7.53 (d, J
3
=
5.2 Hz, 1H), 7.24 (d, J = 7.6 Hz, 1H), 7.07 – 7.02 (m, 1H), 3.88 (s, 2H), 3.86 (s, 2H),
1
3
3
.00(t, J = 5.8 Hz, 2H), 2.84 (t, J = 5.8 Hz, 2H); C NMR (100 MHz, CDCl ) δ 159.9
3
(d, J = 240.1 Hz) , 151.7, 149.3, 140.3 (d, J = 9.0 Hz), 136.8, 135.4, 133.9, 133.7,
1
28.1 (d, J = 3.2 Hz), 124.7, 123.6 (d, J = 9.3 Hz), 112.6 (d, J = 24.9 Hz), 106.7 (d, J
-1
=
22.9 Hz), 58.3, 52.2, 49.8, 23.8; IR (KBr, ν/cm ): 2887, 2756, 1556, 1440, 1407,

ACCEPTED MANUSCRIPT
+
1
183, 1117, 1067, 1045, 859, 772; ESI-MS m/z: 376.9/378.9 [M+H] ; HRMS
+
(
ESI-TOF) calcd for C H BrFN S [M+H] : 377.0118, found: 377.0118.
1
7
15
2
4
.1.3.16. 6-Fluoro-2-((4-methylpyridin-3-yl)methyl)-1,2,3,4-tetrahydrobenzo[4,5]thie
no[2,3-c]pyridine (9c)
Following the general experimental procedure B, compound 9c was obtained as a
white solid (41 mg, 43.5%) from 9b (113 mg, 0.30 mmol) and methylboronic acid (27
o
1
mg, 0.45 mmol). Mp: 113.6 – 115.1 C; H NMR (400 MHz, CDCl ) δ 8.67 – 8.34 (m,
3
2
3
3
1
1
−
H), 7.68 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.25 – 7.22 (m, 2H), 7.07 – 7.02 (m, 1H),
.80 (s, 2H), 3.78 (s, 2H), 2.97 (t, J = 5.6 Hz, 2H), 2.82 (t, J = 5.6 Hz, 2H), 2.48 (s,
1
3
H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J = 240.1 Hz), 150.4, 148.1, 146.6,
3
40.2, 140.1, 136.4, 133.9, 128.1 (d, J = 4.1 Hz), 123.7, 123.6, 112.7 (d, J = 24.9 Hz),
1
9
06.7 (d, J = 22.8 Hz), 56.8, 52.2, 49.8, 23.7, 19.3; F NMR (375 MHz, CDCl ) δ
3
-1
118.61 to −118.67 (m, 1F); IR (KBr, ν/cm ): 2909, 2827, 1604, 1451, 1199, 1117,
+
8
81, 854; ESI-MS m/z: 313.0 [M+H] ; HRMS (ESI-TOF) calcd for C H FN S
18
18
2
+
[
M+H] : 313.1169, found: 313.1169.
4
.1.3.17.6-Fluoro-2-((4-phenylpyridin-3-yl)methyl)-1,2,3,4-tetrahydrobenzo[4,5]thien
o[2,3-c]pyridine (9d)
Following the general experimental procedure B, compound 9d was obtained as a
white solid (63 mg, 55.8%) from 9b (113.2 mg, 0.30 mmol) and phenylboronic acid
o
1
(
54.8 mg, 0.45 mmol). Mp: 141.3 – 142.8 C; H NMR (400 MHz, CDCl ) δ 8.85 (s,
3
1
5
1
H), 8.61 (d, J = 4.4 Hz, 1H), 7.67 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.46 – 7.40 (m,
H), 7.30 (d, J = 5.2 Hz, 1H), 7.21 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 7.06 – 7.01 (m,
1
3
H), 3.76 (s, 2H), 3.74 (s, 2H), 2.88 (t, J = 5.6 Hz, 2H), 2.77 (t, J = 5.4 Hz, 2H); C
NMR (100 MHz, CDCl ) δ 161.9 (d, J = 240.2 Hz), 151.6, 150.8, 147.8, 140.2, 140.1,
3
1
38.2, 136.3, 133.9, 129.1, 128.7, 128.6, 128.1, 128.0, 125.1, 123.7, 123.6, 112.7 (d, J
19
=
24.9 Hz), 106.7 (d, J = 22.8 Hz), 56.2, 51.8, 49.4, 23.8; F NMR (375 MHz, CDCl )
3
-1
δ −118.67 to −118.73 (m, 1F); IR (KBr, ν/cm ): 3062, 2914, 2810, 2767, 1599, 1445,
+
1
117, 892, 887, 832; ESI-MS m/z: 375.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H FN S [M+H] : 375.1326, found: 375.1327.
23
20
2

ACCEPTED MANUSCRIPT
4
.1.3.18. 2-((4-cyclopropylpyridin-3-yl)methyl)-6-fluoro-1,2,3,4-tetrahydrobenzo[4,5]
thieno[2,3-c]pyridine (9e)
Following the general experimental procedure B, compound 9e was obtained as a
white solid (65 mg, 63.5%) from 9b (113 mg, 0.30 mmol) and cyclopropylboronic
o
1
acid (39 mg, 0.45 mmol). Mp: 138.1 – 140.3 C; H NMR (400 MHz, CDCl ) δ 8.60 –
3
8
1
5
0
1
9
1
.34 (m, 2H), 7.68 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.24 (dd, J = 9.2 Hz, J = 2.4 Hz,
H), 7.07 – 7.02 (m, 1H), 6.90 – 6.86 (m, 1H), 3.95 (s, 2H), 3.83 (s, 2H), 2.99 (t, J =
.6 Hz, 2H), 2.83 (t, J = 5.6 Hz, 2H), 2.39 – 2.32 (m, 1H), 1.19 – 1.14 (m, 1H), 0.86 –
1
3
.82 (m, 1H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J = 240.1 Hz) , 156.8, 147.3,
3
46.4, 140.2 (d, J = 8.9 Hz), 136.4, 133.9, 133.5, 128.1 (d, J = 4.2 Hz), 123.7 (d, J =
.3 Hz), 119.4, 112.7 (d, J = 24.9 Hz), 106.7 (d, J = 22.9 Hz), 56.5, 52.3, 49.7, 23.7,
1
9
2.2, 10.5; F NMR (375 MHz, CDCl ) δ −118.63 to −118.69 (m, 1F); IR (KBr,
3
-1
+
ν/cm ): 2925, 2843, 2777, 1599, 1435, 1363, 1117, 793; ESI-MS m/z: 339.1 [M+H] ;
+
HRMS (ESI-TOF) calcd for C H FN S [M+H] : 339.1326, found: 339.1327.
2
0
20
2
4
.1.3.19. 6-Fluoro-2-((4-(prop-1-en-2-yl)pyridin-3-yl)methyl)-1,2,3,4-tetrahydrobenz
o[4,5]thieno[2,3-c]pyridine (9f)
Following the general experimental procedure B, compound 9f was obtained as a
pale yellow oil (91 mg, 53.5%) from 9b (189 mg, 0.50 mmol) and isopropenylboronic
1
acid (65 mg, 0.75 mmol). H NMR (400 MHz, CDCl ) δ 8.67 (s, 1H), 8.46 (d, J = 5.2
3
Hz, 1H), 7.67 (dd, J = 8.4 Hz, J = 4.8 Hz, 1H), 7.22 (dd, J = 8.8 Hz, J = 2.4 Hz, 1H),
7
.07 (d, J = 5.2 Hz, 1H), 7.05 – 7.00 (m, 1H), 5.25 (t, J = 1.6 Hz, 1H), 4.98 (d, J = 0.4
Hz, 1H), 3.77 (s, 2H), 3.74 (s, 2H), 2.89 (t, J = 5.8 Hz, 2H), 2.77 (t, J = 5.6 Hz, 2H),
1
3
2
1
.05 (s, 1H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J = 239.9 Hz), 152.4, 151.3,
3
48.6, 142.9, 140.3 (d, J = 8.8 Hz), 137.0, 133.9, 130.4, 128.2 (d, J = 4.1 Hz), 123.6
(d, J = 9.3 Hz), 122.9, 116.3, 112.5 (d, J = 24.9 Hz), 106.6 (d, J = 22.8 Hz), 56.6, 52.3,
1
9
4
9.6, 24.4, 24.0; F NMR (375 MHz, CDCl ) δ −118.84 to −118.90 (m, 1F); IR (KBr,
3
-1
ν/cm ): 2913, 2763, 1576, 1421, 1263, 1121, 992, 915; 805; ESI-MS m/z: 339.1
+
+
[
M+H] ; HRMS (ESI-TOF) calcd for C H FN S [M+H] : 339.1326, found:
20 20 2
3
39.1325.

ACCEPTED MANUSCRIPT
4
.1.3.20. 6-Fluoro-2-((4-isopropylpyridin-3-yl)methyl)-1,2,3,4-tetrahydrobenzo[4,5]t
hieno[2,3-c]pyridine (9g)
A mixture of 9f (60 mg, 0.18 mmol) and 20% Pd(OH) (30 mg) in MeOH (3 mL)
2
and EtOAc (3 mL) was stirred under H balloon at r.t. After 6 h, the mixture was
2
filtered through Celite. The filtrate was concentrated in vacuo. The residue was then
purified by silica gel column chromatography eluting with 0-10% MeOH/DCM to
1
give 9g (42 mg, 68.5%) as a pale yellow oil. H NMR (400 MHz, CDCl ) δ 8.55 –
3
8
.45 (m, 2H), 7.68 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.27 (d, J = 5.3 Hz, 1H), 7.22 (dd,
J = 9.6 Hz, J = 2.4 Hz, 1H), 7.05 – 7.00 (m, 1H), 3.78 (s, 2H), 3.75 (s, 2H), 3.44 –
3
6
1
1
.37 (m, 1H), 2.90 (t, J = 5.6 Hz, 2H), 2.78 (t, J = 5.6 Hz, 2H), 1.22 (d, J = 6.8 Hz,
1
3
H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J = 240.0 Hz), 159.0 (d, J = 6.2 Hz),
3
50.2 (d, J = 5.5 Hz), 148.6 (d, J = 5.4 Hz), 140.3 (d, J = 8.9 Hz), 136.8, 133.9 (d, J =
.5 Hz), 131.0, 128.2 (d, J = 4.2 Hz), 123.6 (d, J = 9.3 Hz), 121.2, 112.5 (d, J = 24.9
1
9
Hz), 106.6 (d, J = 22.9 Hz), 56.9, 52.4, 49.5, 28.7, 23.9, 23.4; F NMR (375 MHz,
-1
CDCl ) δ −118.75 to −118.81 (m, 1F); IR (KBr, ν/cm ): 2925, 2802, 1573, 1435,
3
+
1
213, 1117, 1035, 805; ESI-MS m/z: 341.1 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H FN S [M+H] : 341.1482, found: 341.1481.
20
22
2
4
.1.3.21. 6-Fluoro-2-((5-fluoropyridin-3-yl)methyl)-1,2,3,4-tetrahydrobenzo[4,5]thie
no[2,3-c]pyridine (9h)
Following the general experimental procedure A, compound 9h was obtained as a
white solid (56 mg, 58.5%) from 20b (63 mg, 0.30 mmol) and
o
1
5
-fluoronicotinaldehyde (46 mg, 0.36 mmol). Mp: 60.8 – 62.6 C; H NMR (400 MHz,
CDCl ) δ 8.42 – 8.41 (m, 2H), 7.68 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.54 – 7.51 (m,
3
1
2
1
8
1
H), 7.24 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 7.07 – 7.02 (m, 1H), 3.80 (s, 2H), 3.78 (s,
1
3
H), 2.94 (t, J = 5.8 Hz, 2H), 2.83 (t, J = 5.6 Hz, 2H); C NMR (100 MHz, CDCl ) δ
3
61.1 (d, J = 240.1 Hz), 159.9 (d, J = 255.4 Hz), 146.0 (d, J = 3.7 Hz), 140.2 (d, J =
.9 Hz), 137.5 (d, J = 23.2 Hz), 136.6, 136.0 (d, J = 3.2 Hz), 133.9 (d, J = 1.5 Hz),
28.1 (d, J = 4.2 Hz), 123.2 (d, J = 17.9 Hz), 112.7 (d, J = 24.9 Hz), 106.7 (d, J = 22.9
19
Hz), 58.2, 52.4, 49.8, 23.8; F NMR (375 MHz, CDCl ) δ −118.65 to −118.71 (m,
3

ACCEPTED MANUSCRIPT
-1
1
F), −127.00, - 127.02 (d, 1F); IR (KBr, ν/cm ): 2914, 2816, 2767, 1600, 1430, 1121,
+
1
023, 887, 793; ESI-MS m/z: 317.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H F N S [M+H] : 317.0919, found: 317.0917.
17
15
2
2
4
.1.3.22. 6-Fluoro-2-[(5-methoxypyridin-3-yl)methyl]-1,2,3,4-tetrahydrobenzo[4,5]th
ieno[2,3-c]-pyridine (9i)
Following the general experimental procedure A, compound 9i was obtained as a
white solid (67 mg, 68.3%) from 20b (63 mg, 0.30 mmol) and
o
1
5
-methoxynicotinaldehyde (50 mg, 0.36 mmol). Mp: 81.3 – 83.1 C; H NMR (400
MHz, CDCl ) δ 8.25 (d, J = 2.8 Hz, 1H), 8.20 (d, J = 1.2 Hz, 1H), 7.67 (dd, J = 8.8
3
Hz, J = 4.8 Hz, 1H), 7.30 (t, J = 2.4 Hz, 1H), 7.24 (dd, J = 9.6 Hz, J = 2.4 Hz, 1H),
7
2
1
1
5
.06 – 7.01 (m, 1H), 3.86 (s, 3H), 3.77 (s, 2H), 3.76 (s, 2H), 2.93 (t, J = 5.6 Hz, 2H),
1
3
.82 (t, J = 5.6 Hz, 2H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J = 240.0 Hz),
3
56.0, 142.6, 140.3 (d, J = 8.9 Hz), 137.2, 136.9, 134.5, 133.9, 128.1 (d, J = 4.2 Hz),
23.6 (d, J = 9.3 Hz), 120.8, 112.6 (d, J = 24.9 Hz), 106.6 (d, J = 22.8 Hz), 55.8, 55.7,
1
9
2.4, 49.7, 23.9; F NMR (375 MHz, CDCl ) δ −118.75 to −118.81 (m, 1F); IR (KBr,
3
-1
ν/cm ): 1914, 2832, 1593, 1588, 1445, 1287, 1171, 1111, 1051, 836, 795; ESI-MS
+
+
m/z: 329.0 [M+H] ; HRMS (ESI-TOF) calcd for C H FN OS [M+H] : 329.1118,
18
18
2
found: 329.1118.
.1.3.23. 6-Fluoro-2-[(5-methylpyridin-3-yl)methyl]-1,2,3,4-tetrahydrobenzo[4,5]thie
4
no[2,3-c]pyridine (9j)
Following the general experimental procedure A, compound 9j was obtained as a
white solid (64 mg, 67.8%) from 20b (63 mg, 0.30 mmol) and
o
1
5
-methylnicotinaldehyde (44 mg, 0.36 mmol). Mp: 120.8 – 122.3 C; H NMR (400
MHz, CDCl ) δ 8.40 – 8.38 (m, 2H), 7.66 (dd, J = 8.4 Hz, J = 4.8 Hz, 1H), 7.60 (s,
3
1
2
H), 7.22 (dd, J = 9.6 Hz, J = 2.4 Hz, 1H), 7.05 – 7.00 (m, 1H), 3.76 (s, 2H), 3.75 (s,
1
3
H), 2.94 (t, J = 5.8 Hz, 2H), 2.82 (t, J = 5.6 Hz, 2H); 2.34 (s, 3H); C NMR (100
MHz, CDCl ) δ 161.0 (d, J = 240.0 Hz), 149.6, 147.5, 140.2 (d, J = 8.9 Hz), 137.6,
3
1
36.6, 133.9 (d, J = 1.5 Hz), 133.3, 132.9, 128.0 (d, J = 4.2 Hz), 123.6 (d, J = 9.3 Hz),
1
9
1
12.6 (d, J = 24.8 Hz), 106.6 (d, J = 22.8 Hz), 58.9, 52.3, 49.7, 23.7, 18.5; F NMR

ACCEPTED MANUSCRIPT
-1
(
375 MHz, CDCl ) δ −118.68 to −118.74 (m, 1F); IR (KBr, ν/cm ): 3073, 2799, 1604,
3
+
1
456, 1352, 1133, 892, 804; ESI-MS m/z: 313.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H FN S [M+H] : 313.1169, found: 313.1168.
18
18
2
4
.1.3.24. 6-Fluoro-2-(pyrimidin-5-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-
c]pyridine (9k)
Following the general experimental procedure A, compound 9k was obtained as a
white solid (64 mg, 71.5%) from 20b (63 mg, 0.30 mmol) and
o
1
pyrimidine-5-carbaldehyde (39 mg, 0.36 mmol). Mp: 109.8 – 111.2 C; H NMR (400
MHz, CDCl ) δ 9.17 (s, 1H), 8.78 (s, 1H), 7.69 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.24
3
(dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 7.07 – 7.02 (m, 1H), 3.80 (s, 2H), 3.79 (s, 2H), 2.95
1
3
(
t, J = 5.8 Hz, 2H), 2.83 (t, J = 5.6 Hz, 2H); C NMR (100 MHz, CDCl ) δ 161.1 (d,
3
J = 240.3 Hz), 158.3, 157.5, 140.2 (d, J = 9.0 Hz), 136.3, 133.9, 131.7, 128.0 (d, J =
4
5
.2 Hz), 123.7 (d, J = 9.3 Hz), 112.7 (d, J = 24.9 Hz), 106.7 (d, J = 22.9 Hz), 56.5,
1
9
2.4, 49.0, 23.8; F NMR (375 MHz, CDCl ) δ −118.58 to −118.64 (m, 1F); IR (KBr,
3
-1
ν/cm ): 3013, 2821, 1566, 1435, 1402, 1177, 1112, 867, 799; ESI-MS m/z:
+
+
3
00.0[M+H] ; HRMS (ESI-TOF) calcd for C H FN S [M+H] : 300.0965, found:
16 15 3
3
00.0965.
.1.3.25. 6-Fluoro-2-(pyridin-4-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3-c]
4
pyridine (9l)
Following the general experimental procedure A, compound 9l was obtained as a
pale yellow oil (65 mg, 71.8%) from 20b (63 mg, 0.30 mmol) and isonicotinaldehyde
1
(
39 mg, 0.36 mmol). H NMR (400 MHz, CDCl ) δ 8.60 (d, J = 5.6 Hz, 2H), 7.71 (dd,
3
J = 8.4 Hz, J = 4.8 Hz, 1H), 7.37 (d, J = 6.0 Hz, 2H), 7.27 (dd, J = 9.6 Hz, J = 2.4 Hz,
1
H), 7.08 – 7.03 (m, 1H), 3.79 (s, 4H), 2.95 (t, J = 5.8 Hz, 2H), 2.85 (t, J = 5.6 Hz,
1
3
2
H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J = 240.1 Hz), 150.0, 147.7, 140.3 (d, J
3
=
8.9 Hz), 136.7, 133.9 (d, J = 1.5 Hz), 128.1 (d, J = 4.2 Hz), 123.9, 123.6 (d, J = 9.2
19
Hz), 112.6 (d, J = 24.9 Hz), 106.6 (d, J = 22.7 Hz), 60.6, 52.5, 49.9, 23.8; F NMR
-1
(
375 MHz, CDCl ) δ −118.66 to −118.73 (m, 1F); IR (KBr, ν/cm ): 2923, 2782, 1568,
3
+
1
421, 1215, 1034, 893, 785; ESI-MS m/z: 299.0 [M+H] ; HRMS (ESI-TOF) calcd for

ACCEPTED MANUSCRIPT
+
C H FN S [M+H] : 299.1013, found: 299.1012.
17
16
2
4
.1.3.26. 2-[(1H-Imidazol-4-yl)methyl]-6-fluoro-1,2,3,4-tetrahydrobenzo[4,5]thieno
[
2,3-c]-pyridine (9m)
Following the general experimental procedure A, compound 9m was obtained as a
white solid (38 mg, 43.8%) from 20b (63 mg, 0.30 mmol) and
o
1
1
H-imidazole-4-carbaldehyde (35 mg, 0.36 mmol). Mp: 173.6 – 175.7 C; H NMR
(
400 MHz, CDCl ) δ 7.66 (dd, J = 8.8 Hz, J = 4.8 Hz, 1H), 7.62 (s, 1H), 7.22 (dd, J =
3
9
5
2
.6 Hz, J = 2.4 Hz, 1H), 7.05 – 7.00 (m, 2H), 3.80 (s, 2H), 3.79 (s, 2H), 2.96 (t, J =
1
3
.6 Hz, 2H), 2.81 (t, J = 5.6 Hz, 2H); C NMR (100 MHz, CDCl ) δ 161.1 (d, J =
3
40.0 Hz), 140.3, 140.2, 136.9, 135.3, 133.9, 128.1 (d, J = 4.1 Hz), 123.7, 123.6,
1
9
1
12.6 (d, J = 24.8 Hz), 106.6 (d, J = 22.7 Hz), 53.2, 52.1, 49.7, 23.9; F NMR (375
-1
MHz, CDCl ) δ −118.77 to −118.83 (m, 1F); IR (KBr, ν/cm ): 2805, 2755, 1610,
3
+
1
577, 1445, 1182, 980, 886, 753; ESI-MS m/z: 288.0 [M+H] ; HRMS (ESI-TOF)
+
calcd for C H FN S [M+H] : 288.0965, found: 288.0967.
1
5
15
3
4
.1.3.27. 6-Fluoro-2-(isoquinolin-4-ylmethyl)-1,2,3,4-tetrahydrobenzo[4,5]thieno[2,3
-c]-pyridine (9n)
Following the general experimental procedure A, compound 27 was obtained as a
white solid (67 mg, 63.6%) from 20b (63 mg, 0.30 mmol) and
o
1
isoquinoline-4-carbaldehyde (57 mg, 0.36 mmol). Mp: 160.8 – 162.1 C; H NMR
400 MHz, CDCl ) δ 9.25 (s, 1H), 8.51 (s, 1H), 8.35 (d, J = 8.4 Hz, 1H), 8.02 (d, J =
(
3
8
.0 Hz, 1H), 7.77 – 7.62 (m, 1H), 7.22 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 7.05 – 7.00
(m, 1H), 4.16 (s, 2H), 3.84 (s, 2H), 3.03 (t, J = 5.8 Hz, 2H), 2.82 (t, J = 5.8 Hz, 2H);
1
3
C NMR (100 MHz, CDCl ) δ 160.1 (d, J = 240.1 Hz), 152.8, 143.1, 140.3 (d, J =
3
8
.5 Hz), 136.7, 135.6, 133.9, 131.0, 128.2, 128.1, 127.6, 124.2, 123.7, 123.6, 112.6 (d,
19
J = 24.9 Hz), 106.6 (d, J = 22.8 Hz), 57.2, 52.4, 49.8, 23.8; F NMR (375 MHz,
-1
CDCl ) δ −118.71 to −118.77 (m, 1F); IR (KBr, ν/cm ): 2909, 2859, 1583, 1435,
3
+
1
358, 1091, 854, 788; ESI-MS m/z: 349.0 [M+H] ; HRMS (ESI-TOF) calcd for
+
C H FN S [M+H] : 349.1169, found: 349.1169.
21
18
2
4
.1.4.1. Tert-butyl [2-(benzo[b]thiophen-3-yl)ethyl]carbamate (11)

ACCEPTED MANUSCRIPT
To a stirred solution of 2-(benzo[b]thiophen-3-yl)acetonitrile (1.50 g, 8.66 mmol),
Nickel (II) chloride hexahydrate (2.06 g, 8.66 mmol), and di-tertbutyl dicarbonate
(3.78 g, 17.32 mmol) in methanol (80 mL) under nitrogen was added sodium
borohydride (1.63 g , 43.3 mmol) in portions over a period of 10 min. The reaction
temperature was kept below 45 °C. The reaction mixture was stirred for 16 h and
diluted with ethyl acetate (200 mL), and then water (300 mL) was carefully added.
The mixture was filtered through kieselghur and ethyl acetate was added (200 mL).
The organic layer was dried (MgSO ), filtered and concentrated in vacuo to afford the
4
crude product, which was purified by flash chromatography eluting with 0-25% ethyl
o
1
acetate/hexanes to give 11 (1.15 g, 47.9%) as a white solid. M.p.: 71 - 72 C; H NMR
(
400 MHz, DMSO-d ) δ 7.96 (d, J = 8.8 Hz, 1H), 7.84 (d, J = 7.6 Hz, 1H), 7.44 –
6
7
1
1
.35 (m, 3H), 6.99 (t, J = 5.6 Hz, 1H), 3.26 (q, J = 6.8 Hz, 2H), 2.94 (t, J = 7.2 Hz,
1
3
H), 1.38 (s, 9H); C NMR (100 MHz, DMSO-d ) δ 155.6, 139.6, 138.8, 133.8,
6
+
24.2, 124.0, 122.9, 122.6, 121.7, 77.6, 28.5, 28.3; ESI-MS m/z: 278.1 [M+H] .
4
.1.4.2. Tert-butyl 3,4-dihydrobenzo[4,5]thieno[2,3-c]pyridine-2(1H)-carboxylate
(12)
A solution of compound 11 (1.08 g, 3.89 mmol), powdered paraformaldehyde (234
mg, 7.78 mmol) and p-toluenesulfonic acid monohydrate (37.1 mg, 0.20 mmol) in
toluene (80 mL) was refluxed under dehydrating conditions for 2 hours. After the
reaction mixture was cooled down to rt, the solvent was evaporated under reduced
pressure. The residue was diluted with water (60 mL) and then extracted with ethyl
acetate (80 mL × 2). The combined organic layers were washed with aqueous
NaHCO (50 mL) and brine (50 mL). The organic layer was dried over anhydrous
3
Na SO , and filtrated, and concentrated. The residue was purified by silica gel column
2
4
o
chromatography eluting with 0-30% ethyl acetate/petroleum (45-60 C) to give 12
1
(
0.76 g, 67.5%) as a white solid. Mp: 88-89 °C; H NMR (400 MHz, DMSO-d ) δ
6
7
.93 (d, J = 7.6 Hz, 1H), 7.67 (d, J = 8.0 Hz, 1H), 7.41 – 7.32 (m, 2H), 4.66 (s, 2H),
13
3
.71 (t, J = 5.6 Hz, 2H), 2.80 (t, J = 5.6 Hz, 2H), 1.44 (s, 9H); C NMR (100 MHz,
DMSO-d ) δ 153.9, 138.4, 137.8, 133.1, 128.4, 124.3, 124.1, 122.6, 120.9, 79.4, 42.9,
6

ACCEPTED MANUSCRIPT
+
4
1.1, 28.0, 23.4; ESI-MS m/z: 290.1 [M+H] .
4
.1.4.3. Ethyl 4-[(4-fluorophenyl)thio]-3-oxobutanoate (14b)
To a solution of 4-fluorobenzenethiol (12.8 g, 100.0 mmol) and ethyl
-chloroacetoacetate (13.5 mL, 100.0 mmol) in CH Cl (300 mL) was dropwisely
4
2
2
added triethylamine (15.2 mL, 150.0 mmol) at 0 °C. The resulting suspension was
stirred at 0 °C for another 2 h, the poured into water (500 mL). After extracted with
DCM (200 mL × 2), the combined organic layers were combined and washed
consequently with saturated NaHCO (100 mL), 0.25 N HCl (80 mL) and brine (100
3
mL). The separated organic layer was dried (Na SO ), concentrated in vacuo, and
2
4
purified by flash column chromatography eluting with 0-10% ethyl acetate/ether
o
petroleum (45-60 C) to afford 14b (24 g, 92.9%) as a pale yellow oil which was used
1
directly for the next step. H NMR (400 MHz, CDCl ) δ 7.39 – 7.34 (m, 2H), 7.03 –
3
6
.97 (m, 2H), 4.17 (q, J = 7.2 Hz, 2H), 3.74 (s, 2H), 3.62 (s, 2H), 1.26 (t, J = 7.2 Hz,
+
3
H); EI-MS m/z: 256 [M] .
4
.1.4.4. Ethyl 4-[(4-chlorophenyl)thio]-3-oxobutanoate (14c)
Compound 14c was obtained as a pale yellow solid (4.69 g, 86%) from
-chlorobenzenethiol (2.89 g, 20.0 mmol) in a manner similar to that as described for
4
the preparation of 14b. The compound was used directly for the next step without
1
further purification. H NMR (400 MHz, CDCl ) δ 7.34 – 7.25 (m, 4H), 4.18 (q, J =
3
+
7
.2 Hz, 2H), 3.79 (s, 2H), 3.62 (s, 2H), 1.26 (t, J = 7.2 Hz, 3H); EI-MS m/z: 272 [M] .
4
.1.4.5. Ethyl 4-[(4-bromophenyl)thio]-3-oxobutanoate (14d)
Compound 14d was obtained as a pale yellow solid (29.3 g, 92.4%) from
-chlorobenzenethiol (18.9 g, 100.0 mmol) in a manner similar to that as described for
4
the preparation of 14b. The compound was used directly for the next step without
1
further purification. H NMR (400 MHz, CDCl ) δ 7.42 – 7.39 (m, 2H), 7.24 – 7.19
3
(m, 2H), 4.17 (q, J = 7.2 Hz, 2H), 3.80 (s, 2H), 3.62 (s, 2H), 1.26 (t, J = 7.2 Hz, 3H);
+
EI-MS m/z: 316 [M] .
4
.1.4.6. Ethyl 4-[(4-methoxyphenyl)thio]-3-oxobutanoate (14e)

ACCEPTED MANUSCRIPT
Compound 14e was obtained as a pale yellow oil (4.6 g, 85.8%) from
4
-methoxybenzenethiol (2.8 g, 20.0 mmol) in a manner similar to that as described for
the preparation of 14b. The compound was used directly for the next step without
1
further purification. H NMR (400 MHz, CDCl ) δ 7.37 – 7.33 (m, 2H), 6.86 – 6.82
3
(m, 2H), 4.18 (q, J = 7.2 Hz, 2H), 3.79 (s, 3H), 3.67 (s, 2H), 3.63 (s, 2H), 1.26 (t, J =
+
7
.2 Hz, 3H); EI-MS m/z: 268 [M] .
4
.1.4.7. Ethyl 2-(5-fluorobenzo[b]thiophen-3-yl) acetate (15b)
o
To a solution of PPA (100 g) in toluene (150 mL) at 100 C (keep stirring) was
added 14b (23.6 g, 92.1 mmol) in toluene (20 mL). The reaction solution was stirred
o
at 100 C overnight under N . The reaction mixture was cooled down to rt and then
2
quenched with ice, basified with potassium carbonate (pH~8) and extracted with ethyl
acetate (200 mL × 3). The organic layers were combined, washed with brine, dried
over anhydrous Na SO , filtrated and concentrated. The residue was purified by silica
2
4
o
gel column chromatography eluting with 0-10% ethyl acetate/petroleum (45-60 C) to
1
give 15b (12.2 g, 55.6%) as a white solid. H NMR (400 MHz, CDCl ) δ 7.76 (dd, J =
3
8
2
.8 Hz, J = 4.8 Hz, 1H), 7.46 – 7.43 (m, 2H), 7.14 – 7.09 (m, 1H), 4.19 (q, J = 6.8 Hz,
19
H), 3.80 (s, 2H), 1.27 (t, J = 6.8 Hz, 3H); F-NMR (375 MHz, CDCl ) δ -118.42 to
3
1
3
-
118.49; C-NMR (100 MHz, CDCl ) δ 170.5, 161.0 (d, J = 240.3 Hz), 139.9 (d, J =
3
9
.1 Hz), 135.6 (d, J = 1.4 Hz), 128.3 (d, J = 4.4 Hz), 127.1, 124.0 (d, J = 9.3 Hz),
+
1
13.4 (d, J = 25.2 Hz), 107.7 (d, J = 23.3 Hz), 61.3, 34.6, 14.3; EI-MS m/z: 238 [M] .
4
.1.4.8. Ethyl 2-(5-chlorobenzo[b]thiophen-3-yl) acetate (15c)
Compound 15c was obtained as a white solid (2.02 g, 47%) from 14c (4.60 g, 16.9
1
mmol) in a manner similar to that as described for the preparation of 15b. H NMR
(
400 MHz, CDCl ) δ 7.76 (d, J = 8.0 Hz, 2H), 7.42 (s, 1H), 7.32 (dd, J = 8.4 Hz, J =
3
1
3
2
.0 Hz, 1H), 4.19 (q, J = 7.2 Hz, 2H), 3.82 (s, 2H), 1.27 (t, J = 7.2 Hz, 3H); C-NMR
(
100 MHz, CDCl ) δ 170.3, 139.9, 138.3, 130.7, 127.9, 126.5, 124.9, 123.8, 121.6,
3
+
6
1.2, 34.4, 14.2; EI-MS m/z: 238 [M] .
4
.1.4.9. Ethyl 2-(5-bromobenzo[b]thiophen-3-yl) acetate (15d)
Compound 15d was obtained as a white solid (7.7 g, 61.8%) from 14d (13.2 g, 41.6