Discovery and structure-activity relationship of thienopyridine derivatives as bone anabolic agents

Article abstract of DOI:10.1016/j.bmc.2013.01.071

A cell-based assay was performed for the discovery of novel bone anabolic agents. Alkaline phosphatase (ALPase) activity of ST2 cells was utilized as an indicator of osteoblastic differentiation, and thienopyridine derivative 1 was identified as a hit compound. 3-Aminothieno[2,3-b]pyridine-2-carboxamide was confirmed to be a necessary core structure for the enhancement of ALPase activity, and then optimization of the C4-substituent on the thienopyridine ring was carried out. Introduction of cyclic amino groups to the C4-position of the thienopyridine ring improved the activity. Especially, N-phenyl-homopiperazine derivatives were found to be strong enhancers of ALPase among this new series. Furthermore, 3-amino-4-(4-phenyl-1,4-diazepan-1-yl)thieno[2,3-b]pyridine-2- carboxamide (15k) was orally administered to ovariectomized (OVX) rats over 6 weeks for evaluating the effects on areal bone mineral density (aBMD), and statistically significant improvements in aBMD were observed from the dosage of 10 mg/kg/day.

Full text of DOI:10.1016/j.bmc.2013.01.071

Bioorganic & Medicinal Chemistry 21 (2013) 1628–1642
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Discovery and structure–activity relationship of thienopyridine
derivatives as bone anabolic agents
b
a
a
b
c
Keiji Saito a, , Akira Nakao , Tsuyoshi Shinozuka , Kousei Shimada , Satoshi Matsui , Kiyoshi Oizumi ,
⇑
Kazuki Yano d, Keiko Ohata e, Daisuke Nakai f, Yoko Nagai f, Satoru Naito g
a Lead Discovery & Optimization Research Laboratories I, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
b Lead Discovery & Optimization Research Laboratories II, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
c Frontier Research Laboratories, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
d Biologics Research Laboratories, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
e Biological Research Laboratories, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
f Drug Metabolism & Pharmacokinetics Research Laboratories, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
g R&D Administration & Support Department, Daiichi Sankyo Co., Ltd, 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A cell-based assay was performed for the discovery of novel bone anabolic agents. Alkaline phosphatase
(ALPase) activity of ST2 cells was utilized as an indicator of osteoblastic differentiation, and thienopyri-
dine derivative 1 was identified as a hit compound. 3-Aminothieno[2,3-b]pyridine-2-carboxamide was
confirmed to be a necessary core structure for the enhancement of ALPase activity, and then optimization
of the C4-substituent on the thienopyridine ring was carried out. Introduction of cyclic amino groups to
the C4-position of the thienopyridine ring improved the activity. Especially, N-phenyl-homopiperazine
derivatives were found to be strong enhancers of ALPase among this new series. Furthermore, 3-
amino-4-(4-phenyl-1,4-diazepan-1-yl)thieno[2,3-b]pyridine-2-carboxamide (15k) was orally administered
to ovariectomized (OVX) rats over 6 weeks for evaluating the effects on areal bone mineral density (aBMD),
and statistically significant improvements in aBMD were observed from the dosage of 10 mg/kg/day.
Ó 2013 Elsevier Ltd. All rights reserved.
Received 22 November 2012
Revised 30 January 2013
Accepted 31 January 2013
Available online 11 February 2013
Keywords:
Osteoporosis
Cell-based screening
Orally active
Bone anabolic agents
Thieno[2,3-b]pyridine
N-Phenyl-homopiperazine
1. Introduction
antiresorptive agents and also reduce fracture incidence.6 How-
ever, the administration period of PTH is limited due to safety con-
Osteoporosis is a skeletal disorder characterized by low bone
mass and deterioration of bone microarchitecture.1 Under these
pathological conditions, bones are more fragile and susceptible to
fractures compared to healthy conditions.2 It is estimated that over
200 million people worldwide have osteoporosis, and the number
is growing with the increasing life expectancy.3
Bone is a dynamically remodeling tissue balanced by the coor-
dinated actions of bone resorbing cells (osteoclasts) and bone
forming cells (osteoblasts). In osteoporosis bone resorption ex-
ceeds bone formation resulting in bone loss. Agents for the treat-
ment of osteoporosis are classified as either antiresorptive or
anabolic.4 Current therapeutic agents are mainly antiresorptive
agents5 such as bisphosphonates, calcitonins, estrogens, selective
estrogen receptor modulators and the RANKL monoclonal anti-
body. On the other hand, recombinant human PTH is the only ap-
proved anabolic agent. PTH therapy has demonstrated that
anabolic agents could increase bone mass to a greater degree than
cerns.6 Under these circumstances, the calcium-sensing receptor,
the Wnt signaling pathway and b-adrenergic receptor have gained
attention as molecular targets for developing bone anabolic
agents.7 However, mechanisms contributing to bone formation
are complex and not yet completely understood. Therefore, we uti-
lized a cell-based screening strategy instead of a target-based
strategy. We believe that a cell-based screening, which detects dif-
ferentiation of stromal cells to osteoblast cells, may provide com-
pounds with a novel mechanism of action, and those compounds
would lead to drug candidates.
For the screening, the stromal cell line ST2, derived from mouse
bone marrow, was utilized, and alkaline phosphatase (ALPase)
activity was detected as an indicator of differentiation to osteo-
blasts.8 By a high-throughput screening of our corporate library,
we identified 3-amino-4-(dimethylamino)thieno[2,3-b]pyridine-
2-carboxamide (1)9 as a hit compound with an EC200 = 0.17
lg/
mL, a concentration to enhance ALPase activity to 200% of control
(Fig. 1). Furthermore, hit compound 1 was evaluated with regard to
calcification in rat bone marrow cells,10 and found to induce the
formation of mineralized nodules. These results indicated that
⇑
Corresponding author. Tel.: +81 3 3492 3131; fax: +81 3 5436 8563.
E-mail address: saito.keiji.e2@daiichisankyo.co.jp (K. Saito).
0968-0896/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmc.2013.01.071

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1629
zyloxycarbonyl group furnished homopiperazines 10a and 10b in
good yields.
N
N
NH2
O
The synthesis of thienopyridine derivatives is shown in
Scheme 2. Compound 1113 was treated with suitable amines to
give enaminothioamides 12. Condensation of 12 with N,N-dimeth-
ylformamide dimethyl acetal (DMF–DMA), and subsequent reflux-
ing in aqueous NaOH afforded thiopyridones 14 via the
intermediates 13.9 Cyclization to the thiopyridone ring was also
performed in DMF or DMA under heating conditions without a
base. Eventually, the resulting thiopyridones 14 were reacted with
2-chloroacetamide in the presence of bases to furnish thienopyri-
S
NH2
1
Figure 1. Hit compound 1.
compound 1 was a promising bone anabolic candidate and encour-
aged us to initiate chemical modification for potentiating the
activity.
In this paper, we report the synthesis of thienopyridine deriva-
tives and structure–activity relationships (SARs) with regard to
enhancement of ALPase activity. In addition, the results of selected
compounds 1 and 15k evaluated in an in vivo animal osteoporosis
model are described.
dines
1 and 15. Since the major product was 4-(dimethyl-
amino)thiopyridone 14a when 3-morpholinobutenethioamide
12g was reacted with DMF–DMA, 4-(dimethoxymethyl)morpho-
line was used instead of DMF–DMA in the preparation of morpho-
line derivative 15g.
The preparation of compounds 15aa, 15ab and 15ac is shown in
Scheme 3. Deprotection of the tert-butoxycarbonyl group of 15h
provided 15aa. Saponification of ester 15t furnished carboxylic
acid 15ab. Carboxamide 15ac was prepared by the hydration of ni-
trile 15s.
2. Chemistry
The synthetic routes for the compounds in Tables 1 and 2 are
outlined in Schemes 1–3.
Scheme 1 describes the preparation of N-aryl-homopiperazine
derivatives, which are employed as the C4-substituent of the thie-
nopyridine ring. Appropriate halobenzenes 2 were coupled with N-
protected homopiperazines 3 using transition metal catalysts,11 or
by nucleophilic aromatic substitution, and followed by cleavage of
the protecting groups to give N-aryl-homopiperazines 5. Benzam-
ides 10a and 10b were prepared from 2,2,2,40-tetrafluoroacetoph-
3. Results and discussion
The effects of the synthesized compounds on cellular ALPase
activity, an indicator of differentiation to osteoblasts, were evalu-
ated using the stromal cell line ST2, derived from mouse bone mar-
row. The results are shown in Tables 1 and 2, and the potency is
expressed as EC200, concentrations to enhance ALPase activity to
200% of control.
enone (6).12 Compound
6
was reacted with benzyl 1-
homopiperazinecarboxylate to afford 7. Compound 7 was treated
with aqueous NaOH to give carboxylic acid 8, and subsequent con-
densation with suitable amines, followed by deprotecting the ben-
Initial chemical efforts were focused on the modification of the
thienopyridine core of hit compound 1. Replacement of the ring
a (for 4a, j, k)
b (for 4b)
c (for 4l, m)
d (for 4c-h)
e (for 4i)
g (for 5a-j, m)
Ar
h (for 5k)
(for 5l)
Ar
NH
N
f (for 4n)
i
N
ArX
N
N
N
H
R1
R1
3
5a-m
2
4a-n
: Ar = Ph, R1 = Boc
: Ar = 4-i-PrO-C H , R1 = Boc
6 4
a
b
c
d
e
f
h
i
j
k
: Ar = 2-Me-C H , R1 = Boc
: Ar = 4-CN-C H , R1 = Boc
6 4
: Ar = 3-Me-C6H4, R1 = Boc
: Ar = 4-Me-C6H4, R1 = Boc
: Ar = 4-EtOC(O)-C H , R1 = Boc
6 4
: Ar = 4-Me NC(O)CH -C H , R1 = Cbz
2
2
6 4
6
: Ar = 4-F-C H ,4R1 = Boc
: Ar = 2-pyridyl, R1 = Boc
l
6
: Ar = 4-t-Bu-C4H , R1 = Boc
: Ar = 4-pyridyl, R1 = Boc
m
6
4
: Ar = 4-MeO-C H , R1 = Boc
: Ar = 2-thiazolyl, R1 = H
g
n
6
4
O
R2
O
O
R2
e
NH
h
N
CF3
N
N
N
Cbz
F
Cbz
N
H
10a, b
6
3
R2 = CF3
R2 = OH
7
8
9a
9b
j
: R2 = NMe2
: R2 = NHMe
10a
10b
k
R2 = NMe2
l
R2 = NHMe
Scheme 1. Reagents and conditions: (a) Pd2(dba)3, 2-dicyclohexylphosphino-20-(N,N-dimethylamino)biphenyl, NaOt-Bu, t-BuOH, 1,4-dioxane, 100 °C; (b) Pd(OAc)2, 2,8,9-
triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane, NaOt-Bu, toluene, 80 °C; (c) Pd2(dba)3, 1,3-bis-(2,6-diisopropylphenyl)-imidazolium chloride, KOt-Bu, 1,4-
dioxane, 90 °C; (d) CuI, K2CO3, ethylene glycol, i-PrOH, 80 °C; (e) Et3N, DMSO, 100 °C; (f) n-BuOH, reflux; (g) HCl, MeOH, 1,4-dioxane, rt; (h) H2, Pd/C, EtOH, rt; (i) TFA, CH2Cl2,
rt; (j) aq NaOH, DMF, 80 °C, 93%; (k) CDI, Me2NH, THF, rt, 100%; (l) CDI, MeNH2, THF, rt, 100%.

1630
K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
R3
R4
R3
R4
OEt
S
N
S
m
n
or
o
or
p
N
S
NH2
NH2
N
N
CN
CN
CN
11
12a-z
13a-z
R3
R4
R3
R4
N
q or r
N
N
NH2
CN
S
O
S
N
H
NH2
14a-z
1, 15b-z
R3R4N- =
a : Me2N-
b : n-PrHN-
c :
k-z :
Ar
N
N
N
H
Ar = k : Ph, l : 2-Me-C6H4, m : 3-Me-C6H4,
n : 4-Me-C6H4, o : 4-F-C6H4, p : 4-t-Bu-C6H4,
q : 4-MeO-C6H4, r : 4-i-PrO-C6H4, s : 4-CN-C6H4,
t : 4-EtOC(O)-C6H4, u : 4-Me2NC(O)-C6H4
v : 4-MeHNC(O)-C6H4, w : 4-Me2NC(O)CH2-C6H4
x : 2-pyridyl, y : 4-pyridyl, z : 2-thiazolyl
d : (n-Pr)2N-
e : 1-pyrrolidyl
f : 1-piperidyl
g : 4-morpholino
h-j :
R5
N
N
R
5
= h : Boc, i : Me, j : Ph
Scheme 2. Reagents and conditions: (m) R3R4NH, EtOH, rt; (n) N,N-dimethylformamide dimethyl acetal, toluene, reflux, then aq NaOH, reflux; (o) N,N-dimethylformamide
dimethylacetal, DMF or EtOH, rt, then DMF or DMA,
(r) 2-chloroacetamide, NaOEt, DMF, rt.
D
; (p) 4-(dimethoxymethyl)morpholine, toluene, reflux, then aq NaOH, reflux; (q) 2-chloroacetamide, aq NaOH, DMF, rt;
s (for 15aa)
t (for 15ab)
u (for 15ac)
R3
R4
R3
R4
N
N
N
NH2
NH2
O
O
S
S
NH2
NH2
N
15h, 15t, 15s
15aa, 15ab, 15ac
O
O
O
OEt
OH
NH2
CN
BOC
N
H
N
N
N
N
N
R3
R4
=
N
N
N
N
N
N
N
15h
15t
15s
15ac
15aa
15ab
Scheme 3. Reagents and conditions: (s) HCl, MeOH, 1,4-dioxane, rt, 100%; (t) aq NaOH, EtOH, reflux, 79%; (u) 30% H2O2, K2CO3, DMSO, rt, 71%.
nitrogen by a carbon atom leading to benzothiophene reduced po-
tency substantially. The same reduction in potency was found for
thieno[3,2-c]pyridine, a structural isomer of thieno[2,3-b]pyridine,
with a different location of the ring nitrogen atom. Conversion of
the thienopyridine ring to a thienopyrimidine ring also resulted
in a complete loss of activity (data not shown). These results sug-
gest that the ring nitrogen atom plays a pivotal role for its activity.
We then investigated the effects of substituents on the thieno-
pyridine ring. Replacement of the carboxamide group at the C2-po-
sition and the amino group at the C3-position with the other
substituents, such as hydrogen, methyl, cyano, ester and carboxylic
acid, resulted in significantly less active or even inactive com-
pounds (data not shown). On the other hand, manipulation of the
dimethyl amino group at the C4-position was found to be flexible.
Hence, this region was examined extensively.
The results are summarized in Table 1. We first introduced pri-
mary amines to the C4-position. Although n-propyl-amino analog
15b was less active, balkier cyclohexyl-amino analog 15c showed
moderate activity with an EC200 value of 0.24 lg/mL. However,
compound 15c was still less potent than 1. We then incorporated
secondary amino groups. The activity of N,N-dipropyl-amino ana-
log 15d was dramatically reduced from the N,N-dimethyl-amino
analog 1. However, cyclic amino groups were found to be effective.
Especially, piperidine analog 15f was threefold more potent than 1.

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1631
Table 1
Table 2
Effects of 4-aminothienopyridine derivatives on ALP activity in ST2 cellsa
Effects of N-aryl-homopiperazine derivatives on ALP activity in ST2 cellsa
R
Ar
N
NH2
4
3
O
2
S
NH2
g/mL)
N
N
NH2
O
Metabolic stabilityc (%)
b
Compound
–R
EC200
0.17
(l
S
NH2
N
1
–NMe2
48
—
H
134%d
b
15b
Compound
Ar
Ph
EC200 (lg/mL)
N
H
N
15k
15l
0.051
>1.0
0.074
0.044
0.082
0.27
0.035
>1.0
0.099
0.193
>1.0
2-Me-C6H4
3-Me-C6H4
4-Me-C6H4
4-F-C6H4
4-t-Bu-C6H4
4-MeO-C6H4
4-i-PrO-C6H4
4-CN-C6H4
4-EtOC(O)-C6H4
4-HOC(O)-C6H4
4-Me2NC(O)-C6H4
4-MeHNC(O)-C6H4
4-H2NC(O)-C6H4
4-Me2NC(O)CH2-C6H4
15c
15d
0.24
—
—
15m
15n
15o
15p
15q
15r
110%d
N
N
15e
15f
0.29
—
2
15s
15t
N
N
N
N
N
0.067
15ab
15u
15v
15ac
15w
O
15g
15aa
15i
0.44
82
—
0.014
0.023
0.079
0.003
105%d
117%d
0.10
NH
N
Me
Ph
—
15x
0.059
N
N
N
15j
91
15y
15z
0.091
0.036
15k
0.051
71
N
N
Ph
S
N
a
Values are the arithmetic means of at least two experiments. Standard devia-
tion of assay is less than 10%.
a
Values are the arithmetic means of at least two experiments. Standard devia-
b
Concentration to enhance ALP activity in ST2 cell to 200% of control.
Stability is described as % remaining after 30 min incubation with the rat liver
tion of assay is less than 10%.
c
b
Concentration to enhance ALP activity in ST2 cell to 200% of control.
microsome.
d
% Enhancement at 0.30 lg/mL.
higher activity than unsubstituted compound 15k. We then fo-
cused on the steric and electronic effects of the substituents at
the C4-position of the benzene ring. Fluorine substitution (15o)
was detrimental. Introduction of a methoxy group (15q) resulted
in a slight increase in activity. The activity of i-propoxy analog
15r was dramatically reduced from the methoxy analog 15q. A
similar tendency was observed with alkyl derivatives (15n vs
15p). These results suggest that sterically hindered and lipophilic
groups are disfavored around this position. We then examined
electron withdrawing groups. Nitrile analog 15s and ethyl ester
analog 15t showed lower activity than 15k, and hydrolysis of 15t
into the carboxylic acid 15ab resulted in a substantial loss of activ-
ity. Although carboxamide analog 15ac showed moderate activity,
N-methylamide 15v and N,N-dimethylamide 15u provided a major
boost in activity, and 15u was fourfold more potent than 15k. Fur-
thermore, insertion of a methylene group between the N,N-dim-
ethylcarboxamide group and the benzene ring of 15u produced
compound 15w, which gave 15-fold higher activity
However, this compound was metabolically unstable. Whereas,
morpholine analog 15g was less potent than 1 but metabolically
more stable. These results led us to investigate piperazine deriva-
tives to both enhance the activity and improve the metabolic sta-
bility. Although the unsubstituted and N-methyl-piperazine
derivatives (15aa and 15i) showed very weak activities, N-phe-
nyl-piperazine analog 15j demonstrated higher activity than 1
with an EC200 value of 0.10 lg/mL. We next attempted to expand
the six-membered piperazine ring to a seven-membered homopip-
erazine ring. N-Phenyl-homopiperazine analog 15k showed good
activity, which was more than threefold as potent as that of 1
(EC200 = 0.051 lg/mL). Furthermore, compound 15k was metaboli-
cally moderately stable. Therefore, N-phenyl-homopiperazine
derivatives were examined in detail.
We first examined the effect of a methyl group placed on the
benzene ring of 15k. C2-Substiution (15l) resulted in a significant
loss of activity. Although C3-substituted compound 15m showed
slightly lower activity, C4-substituted compound 15n had slightly
(EC200 = 0.003
lg/mL) than 15k. These results suggest that the
incorporation of hydrogen bond acceptors into its proper location
Table 3
PK parameters of 1 and 15k in F344 rata
Compound
clogPc
Cl (mL/min/kg)
po
Vd (L/kg)
t1/2 (h)
Cmax
(l
g/mL)
AUC (
l
g h/mL)
po
F (%)
iv
iv
po
iv
po
iv
po
iv
1b
1.7
3.0
39
29
45
34
1.1
4.2
3.1
8.1
0.33
2.77
0.78
3.22
—
—
5.59
2.54
0.87
1.1
9.4
9.5
87
71
15kb
a
b
c
Mean (n = 3).
po 25 mg/kg, 0.5% carboxymethyl cellulose; iv 2 mg/kg, N,N-dimethylacetamide/distilled water (5/95).
The clogP values were calculated by CLOGP software (CLOGP Daylight Version 4.83, Daylight Chemical Information Systems, Inc.).

1632
K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
is beneficial to enhance the activity. Replacement of the benzene
ring of 15k with heteroaryl rings (15x–z) resulted in comparable
activities.
80
60
40
††
†
*
With the promising in vitro activities, compounds 1, 15k and
15w were selected for pharmacokinetics studies in the rat (Table 3).
Hit compound 1 had good oral exposure with a bioavailability of
86%, but also had a short plasma half-life (0.78 h). The bioavailabil-
ity and oral exposure for compound 15k were also favorable, fur-
thermore, 15k had a longer plasma half-life (3.22 h). These PK
profiles indicated that compound 15k could be a candidate for
in vivo pharmacological evaluation with once daily dosing. Unfor-
tunately, compound 15w, which showed the most potent activity,
#
20
0
sham vehicle
60
b.i.d.
Comp. 1
10 30 mg/kg/day
Comp. 15k
was inferior in PK with low Cmax (0.08 lg/mL, 3 mg/kg, po).
OVX
We next sought to test compounds 1 and 15k in vivo. Com-
pounds 1 and 15k were administered to ovariectomized (OVX)
rats, a model of postmenopausal osteoporosis, at the doses of
60 mg/kg/day (po, b.i.d) and 10, 30 mg/kg/day (po, q.d.), respec-
tively, over 6 weeks. Their areal bone mineral density (aBMD) of
distal femurs, femoral diaphyses and proximal tibiae, and serum
osteocalcin (a marker for the bone formation)14 concentrations
after six weeks were compared to those of vehicle control and
sham-operated rats. As shown in Figure 2, vehicle control OVX rats
showed significant decreases in aBMD compared to sham-operated
rats, and treatment with these two compounds significantly in-
creased all parts of aBMD. Especially, aBMD recovered almost equal
to that of sham-operated rats upon treatment with 30 mg/kg/day
of 15k. Both of the thienopyridine derivatives increased the aBMD
of femoral diaphyses remarkably. Furthermore, these compounds
also increased the serum osteocalcin concentration, consistent
with an elevation in bone formation activity (Fig. 3). The observed
in vivo pharmacodynamic effects with 10 mg/kg/day (q.d.) of 15k
were comparable to those with 60 mg/kg/day (b.i.d.) of 1, consis-
tent with their in vitro activities and pharmacokinetics parameters.
It is fair to say that these results provided proof-of-concept for this
lead discovery and optimization strategy of novel bone anabolic
agents.
Figure 3. Effects of compound 1 and 15k on serum osteocalcin concentration in
OVX rat model. Data are presented as the mean SE (n = 8–9). #p <0.05 versus sham
group, ⁄p <0.05 versus vehicle group, as determined using Student’s t-test. p <0.05,
p <0.01 versus vehicle group, as determined using Dunnett’s test.
4. Conclusion
Thienopyridine derivative 1 was identified as a compound stim-
ulating osteoblastic differentiation by an assay evaluating alkaline
phosphatase (ALPase) activity in ST2 cells. Extensive SAR studies
led to the discovery of 3-amino-4-(4-phenyl-1,4-diazepan-1-
yl)thieno[2,3-b]pyridine-2-carboxamide (15k), which was found
to be a stronger enhancer of ALPase and had better pharmacoki-
netic properties compared to 1. Furthermore, 15k showed statisti-
cally significant improvements of aBMD from the dosage of 10 mg/
kg/day in an in vivo study using a rat model of postmenopausal
osteoporosis. The mechanism of action has not yet been made
clear, and mechanism investigations are underway. Also, further
structural optimization and biological evaluations of the novel thi-
enopyridine derivatives are ongoing. These results will be reported
in due course.
Total femurs
**
Distal femurs
††
120
115
110
130
††
††
**
††
125
120
115
110
##
##
105
30 mg/kg/day
60
b.i.d.
10
10
30 mg/kg/day
Comp. 15k
60
b.i.d.
Sham
Vehicle
Sham
Vehicle
Comp. 1
Comp. 15k
Comp. 1
OVX
OVX
Femoral diaphyses
Proximal tibiae
**
††
120
115
110
105
100
95
††
††
**
††
##
90
100
85
10
30 mg/kg/day
60
b.i.d.
30 mg/kg/day
10
60
b.i.d.
Sham Vehicle
Sham
Vehicle
Comp. 15k
Comp. 1
Comp. 15k
Comp. 1
OVX
OVX
Figure 2. Effects of compound 1 and 15k on aBMD in the OVX rat model. Data are presented as the mean SE (n = 8–9). ##p <0.01 versus sham group, ⁄⁄p <0.01 versus vehicle
group, as determined using Student’s t-test. p <0.01 versus vehicle group, as determined using Dunnett’s test.

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1633
cooling to room temperature, water was added to the reaction
mixture, and the mixture was extracted with ethyl acetate. The
combined organic phases were washed with brine, dried over
anhydrous Na2SO4 and concentrated in vacuo. The obtained resi-
due was purified by silica gel column chromatography (hexane/
ethyl acetate = 3:1) to give the title compound (812 mg, 35%) as
pale yellow oil. IR (film) 2974, 1695, 1602, 1498, 1415, 1175,
5. Experimental
5.1. Chemistry
5.1.1. General
Unless otherwise noted, materials were obtained from commer-
cial suppliers and used without further purification. Melting points
were determined in a Yanaco micro melting point apparatus and
are uncorrected. IR absorption spectra were recorded on a Jasco
FT/IR-610 spectrophotometer. NMR spectra were recorded on a
Varian Mercury 400 or 500 spectrometer with tetramethylsilane
as an internal reference. The mass spectra (Low- or High-resolution
mass) spectroscopy was carried out with a JEOL GCmate or JEOL
JMS-AX505H. Elemental analyses were performed by the analytical
department of Daiichi Sankyo RD Novare Co., Ltd. TLC analysis was
performed on 60F254 plates (Merck 5715). Separation of the com-
pounds by column chromatography was carried out with silica gel
60 (Merck, 230–400 mesh ASTM).
930, 692 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.36 (4.5H, s), 1.44
;
(4.5H, s), 1.92–1.98 (2H, m), 2.28 (3H, s), 3.19 (1H, t, J = 5.9 Hz),
3.29 (1H, t, J = 5.9 Hz), 3.49–3.54 (6H, m), 6.46–6.48 (3H, m), 7.06
(1H, t, J = 7.1 Hz); HRMS m/z calcd for C17H26O2N2 290.1994, found
290.1981; Anal. Calcd for C17H26N2O2ꢁ0.16H2O: C, 69.62; H, 9.05;
N, 9.55. Found: C, 69.71; H, 9.36; N, 9.28.
5.1.5. tert-Butyl 4-(p-tolyl)-1,4-diazepane-1-carboxylate (4d)
The title compound was prepared in a similar manner described
for 4c. Yield: 36%; colorless oil; IR (film) 2974, 2929, 1695, 1619,
1521, 1415, 1365, 1237, 1169 cmꢀ1 1H NMR (CDCl3, 400 MHz) d
;
1.38 (4.5H, s), 1.44 (4.5H, s), 1.91–2.01 (2H, m), 2.23 (3H, s), 3.18
(1H, t, J = 5.9 Hz), 3.20 (1H, t, J = 5.9 Hz), 3.46–3.59 (6H, m), 6.60
(2H, d, J = 8.2 Hz), 7.00 (2H, d, J = 8.2 Hz); MS (EI) m/z: 290 [M+].
5.1.2. tert-Butyl 4-phenyl-1,4-diazepane-1-carboxylate (4a)
Tris(dibenzylideneacetone)dipalladium(0)
(458 mg,
0.500
mmol), 2-dicyclohexylphosphino-20-(N,N-dimethylamino)biphe-
nyl (787 mg, 2.00 mmol) and sodium tert-butoxide (1.35 g,
14.0 mmol) were put into an oven-dried flask. tert-Butanol
(10 mL), 1,4-dioxane (20 mL), iodobenzene (1.12 mL, 10.0 mmol)
and 1-(tert-butoxycarbonyl)homopiperazine (2.40 g, 12.0 mmol)
were successively added to the flask at room temperature, and
the mixture was stirred under reflux for 2 h under N2 atmosphere.
After cooling to room temperature, diethyl ether was added to the
reaction mixture, the insolubles were removed by filtration, and
the filtrate was concentrated in vacuo. The obtained residue was
purified by silica gel column chromatography (hexane/ethyl ace-
tate = 10:1) to give the title compound (2.76 g, 100%) as pale yel-
low oil. IR (film) 2974, 1694, 1599, 1506, 1415, 1237, 1169, 930,
5.1.6. tert-Butyl 4-(4-fluorophenyl)-1,4-diazepane-1-
carboxylate (4e)
The title compound was prepared in a similar manner described
for 4c. Yield: 45%; white solid; mp 88–89 °C; IR (KBr) 2968,
;
2921,1682, 1515, 1418, 1244, 828 cmꢀ1 1H NMR (CDCl3,
400 MHz) d 1.36 (4.5H, s), 1.43 (4.5H, s), 1.90–2.01 (2H, m), 3.21
(1H, t, J = 5.9 Hz), 3.32 (1H, t, J = 5.9 Hz), 3.46–3.63 (6H, m), 6.58–
6.64 (2H, m), 6.92 (2H, t, J = 8.6 Hz); MS (EI) m/z: 294 [M+]; Anal.
Calcd for C16H23FN2O2ꢁ0.14H2O: C, 64.73; H, 7.90; N, 9.44; F,
6.40. Found: C, 64.77; H, 7.92; N, 9.36; F, 6.37.
5.1.7. tert-Butyl 4-(4-tert-butylphenyl)-1,4-diazepane-1-
carboxylate (4f)
748, 692 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.37 (4.5H, s), 1.44
;
The title compound was prepared in a similar manner described
for 4c. Yield: 9%; white solid; mp 62–64 °C; IR (KBr) 2962, 1686,
(4.5H, s), 1.93–2.00 (2H, m), 3.19 (1H, t, J = 5.9 Hz), 3.80 (1H, t,
J = 5.9 Hz), 3.51–3.57 (6H, m), 6.63–6.69 (3H, m), 7.19 (2H, t,
J = 7.1 Hz); HRMS m/z calcd for C16H24O2N2 276.1835, found
276.1833; Anal. Calcd for C16H24N2O2ꢁ0.14H2O: C, 68.90; H, 8.77;
N, 10.04. Found: C, 68.96; H, 8.75; N, 9.85.
1520, 1420, 1364, 1246, 1170 cmꢀ1 1H NMR (CDCl3, 400 MHz) d
;
1.27 (9H, s), 1.35 (4.5H, s), 1.43 (4.5H, s), 1.91–2.00 (2H, m), 3.21
(1H, t, J = 5.9 Hz), 3.32 (1H, t, J = 5.9 Hz), 3.48–3.59 (6H, m), 6.62
(2H, d, J = 8.8 Hz), 7.20 (2H, d, J = 8.8 Hz); MS (EI) m/z: 332 [M+].
5.1.3. tert-Butyl 4-(o-tolyl)-1,4-diazepane-1-carboxylate (4b)
5.1.8. tert-Butyl 4-(4-methoxyphenyl)-1,4-diazepane-1-
carboxylate (4g)
To
a toluene (20 mL) solution of 2-iodotoluene (2.18 g,
10.0 mmol) was added 1-(tert-butoxycarbonyl)homopiperazine
(2.40 g, 12.0 mmol), palladium(II) acetate (89.8 mg, 0.400 mmol),
2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane
(137 mg, 0.400 mmol) and sodium tert-butoxide (1.35 g,
14.0 mmol). The mixture was stirred at 80 °C for 18 h under N2
atmosphere. After cooling to room temperature, diethyl ether was
added to the reaction mixture, the insolubles were removed by fil-
tration, and the filtrate was concentrated in vacuo. The obtained
residue was purified by silica gel column chromatography (hex-
ane/ethyl acetate, 5:1) to give the title compound (754 mg, 26%)
as pale yellow oil. IR (film) 2975, 1695, 1492, 1413, 1159, 762,
The title compound was prepared in a similar manner described
for 4c. Yield: 41%; brown liquid; IR (film) 2974, 1693, 1513, 1415,
1242, 1169, 1041, 930, 815 cmꢀ1 1H NMR (CDC13, 500 MHz) d 1.37
;
(4.5H, s), 1.44 (4.5H, s), 1.92–1.99 (2H, m), 3.20 (1H, t, J = 5.9 Hz),
3.31 (1H, t, J = 5.9 Hz), 3.47–3.57 (6H, m), 3.74 (3H, s), 6.65 (2H, d,
J = 9.3 Hz), 6.81 (2H, d, J = 9.3 Hz); HRMS m/z calcd for C17H26N2O3
306.1943, found 306.1935; Anal. Calcd for C17H26N2O3ꢁ0.36H2O: C,
65.26; H, 8.61; N, 8.95. Found: C, 64.92; H, 8.29; N, 8.87.
5.1.9. tert-Butyl 4-(4-isopropoxyphenyl)-1,4-diazepane-1-
carboxylate (4h)
725 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.47–1.48 (9H, m), 1.87–
;
The title compound was prepared in a similar manner described
for 4c. Yield: 14%; colorless oil; IR (film) 2974, 1694, 1511, 1415,
1.97 (2H, m), 2.29 (3H, s), 3.00–3.10 (4H, m), 3.52–3.60 (4H, m),
6.92 (1H, t, J = 7.8 Hz), 7.01 (1H, d, J = 7.8 Hz), 7.08–7.14 (2H, m);
HRMS m/z calcd for C17H26O2N2 290.1994, found 290.1977.
1366, 1237, 1168, 1122 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.28
;
(6H, d, J = 5.9 Hz), 1.37 (4.5H, s), 1.43 (4.5H, s), 1.90–2.00 (2H,
m), 3.20 (1H, t, J = 5.9 Hz), 3.31 (1H, t, J = 5.5 Hz), 3.40–3.61 (6H,
m), 4.32–4.38 (1H, m), 6.61 (2H, d, J = 9.0 Hz), 6.78 (2H, d,
J = 9.0 Hz); MS (EI) m/z: 334 [M+].
5.1.4. tert-Butyl 4-(m-tolyl)-1,4-diazepane-1-carboxylate (4c)
CuI (80.0 mg, 0.420 mmol) and K3PO4 (3.40 g, 16.0 mmol) were
put into an oven-dried flask. 2-Propanol (8.0 mL), ethylene glycol
(0.90 mL, 16.0 mmol), 3-iodotoluene (1.03 mL, 8.00 mmol) and 1-
(tert-butoxycarbonyl)-homopiperazine (1.89 mL, 9.6 mmol) were
successively added to the flask at room temperature. The reaction
mixture was stirred at 80 °C for 10 h under N2 atmosphere. After
5.1.10. tert-Butyl 4-(4-cyanophenyl)-1,4-diazepane-1-
carboxylate (4i)
4-Fluorobenzonitrile (1.21 g, 10.0 mmol), 1-(tert-butoxycar-
bonyl)homopiperazine (1.96 mL, 10.0 mmol) and triethylamine

1634
K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
(1.53 mL, 11.0 mmol) were dissolved in dimethylsulfoxide (20 mL)
and the mixture was stirred at 100 °C for 16 h. After cooling to
room temperature, the mixture was diluted with ethyl acetate,
washed successively with water and brine, dried over anhydrous
Na2SO4 and concentrated in vacuo. The residue was purified by sil-
ica gel column chromatography (hexane/ethyl acetate, 2:1) to give
the title compound (1.90 g, 63%) as pale yellow oil. IR (film) 2975,
2214, 1691, 1606, 1521, 1417, 1365, 1240, 1178, 929, 819,
for 24 h. After cooling to room temperature, the insolubles were re-
moved by filtration, and the filtrate was concentrated in vacuo. The
residue was diluted with 1 M aqueous solution of NaOH (30 mL),
and the mixture was extracted with CH2Cl2 (3 ꢂ 100 mL). The com-
bined organic phases were dried over Na2SO4, and concentrated in
vacuo. The residue in methanol (30 mL) was added 4 M hydrogen
chloride in 1,4-dioxane (30 mL) was added. The deposited hydro-
chloride salt was separated by filtration and washed with 1,4-diox-
ane. The obtained solid was mixed with 1 M aqueous solution of
NaOH (60 mL), and the mixture was extracted with CH2Cl2
(3 ꢂ 50 mL). The extract was dried over anhydrous Na2SO4 and
concentrated in vacuo to give the title compound (3.60 g, 73%) as
544 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 1.16 (4.5H, s), 1.28
;
(4.5H, s), 1.68–1.85 (2H, m), 3.17 (1H, t, J = 5.9 Hz), 3.25 (1H, t,
J = 5.5 Hz), 3.44–3.68 (6H, m), 6.81 (2H, d, J = 9.4 Hz), 7.48 (2H,
dd, J = 9.4, 3.5 Hz); HRMS m/z calcd for C17H23N3O2 301.1790,
found 301.1784.
pale yellow oil. IR (neat) 3304, 1534, 1139, 614 cmꢀ1 1H NMR
;
(CDCl3, 400 MHz) d 1.90–1.96 (2H, m), 2.89–2.91 (2H, m), 3.04–
3.07 (2H, m), 3.66–3.70 (4H, m), 6.44 (1H, d, J = 3.5 Hz), 7.15 (1H,
d, J = 3.5 Hz); MS (EI) m/z: 183 [M+].
5.1.11. tert-Butyl 4-(4-ethoxycarbonylphenyl)-1,4-diazepane-1-
carboxylate (4j)
The title compound was prepared in a similar manner described
for 4a. Yield: 44%; brown oil; IR (film) 2976, 1697, 1605, 1522,
5.1.16. 1-Phenyl-1,4-diazepane (5a)
1415, 1364, 1281, 1183, 1108, 770 cmꢀ1
;
1H NMR (CDCl3,
To a methanol (5.0 mL) solution of 4a (2.76 g, 10.0 mmol) was
added 4 M hydrogen chloride in 1,4-dioxane (15 mL), and the mix-
ture was stirred at room temperature for 1 h and concentrated in
vacuo. The residue was treated with aqueous solution of potassium
carbonate (100 mL), and the mixture was extracted with a mixed
solvent of CH2Cl2/2-propanol (4:1, 3 ꢂ 100 mL). The extract was
dried over anhydrous Na2SO4 and concentrated in vacuo to give
the title compound (1.44 g, 82%) as yellow liquid. IR (film) 2931,
400 MHz) d 1.36 (3H, t, J = 7.0 Hz), 1.36 (4.5H, s), 1.43 (4.5H, s),
1.91–2.02 (2H, m), 3.20 (1H, t, J = 5.9 Hz), 3.30 (1H, t, J = 5.9 Hz),
3.51–3.66 (6H, m), 4.30 (2H, q, J = 7.0 Hz), 6.65 (2H, d, J = 9.0 Hz),
7.87 (2H, d, J = 9.0 Hz); MS (FAB) m/z: 348 [M+].
5.1.12. Benzyl 4-{4-[2-(dimethylamino)-2-oxoethyl]phenyl}-
1,4-diazepane-1-carboxylate (4k)
1598, 1506, 1394, 1245, 1035, 748, 692 cmꢀ1 1H NMR (CDCl3,
;
The reaction was performed following the method described for
4a using 2-(4-bromophenyl)-N,N-dimethyl acetamide15 and benzyl
1-homopiperazinecarboxylate. Yield: 80%; yellow oil; IR (film)
500 MHz) d 1.87–1.92 (2H, m), 2.83 (2H, t, J = 5.9 Hz), 3.03 (2H, t,
J = 5.5 Hz), 3.54–3.59 (4H, m), 6.65 (1H, t, J = 8.3 Hz), 6.70 (2H, d,
J = 8.3 Hz), 7.21 (2H, t, J = 8.3 Hz); HRMS m/z calcd for C11H16N2
176.1313, found 176.1318.
;
3481, 2939, 1699, 1642, 1520, 1423 cmꢀ1 1H NMR (CDCl3,
400 MHz) d 1.90–2.06 (2H, m), 2.95 (3H, s), 3.00 (3H, s), 3.27–
3.33 (1H, m), 3.34–3.40 (1H, m), 3.50–3.67 (8H, m), 5.08 (1H, s),
5.13 (1H, s), 6.60–6.68 (2H, m), 7.10 (2H, d, J = 8.2 Hz), 7.27–7.40
(5H, m); MS (FAB) m/z: 396 [M+H]+.
5.1.17. 1-(o-Tolyl)-1,4-diazepane (5b)
The title compound was prepared from 4b in a similar manner
described for 5a. Yield: 100%; yellow liquid; IR (film) 2938, 2831,
5.1.13. tert-Butyl 4-(2-pyridyl)-1,4-diazepane-1-carboxylate (4l)
Potassium tert-butoxide (1.68 g, 15.0 mmol), tris(dibenzylidene-
acetone)dipalladium(0) (91.6 mg, 0.100 mmol) and 1,3-bis-
(2,6-diisopropylphenyl)-imidazolium chloride (85.0 mg, 0.200 mmol)
were mixed in 1,4-dioxane (20 mL) under N2 atmosphere, and a 1,4-
dioxane (10 mL) solution of 2-bromopyridine (2.37 g, 15.0 mmol) and
1-(tert-butoxycarbonyl)homopiperazine (2.00 g, 10.0 mmol) was
added dropwise. After stirring at room temperature for 12 h, the mix-
ture was diluted with water, and the insolubles were removed by fil-
tration. The filtrate was extracted with ethyl acetate, and the extract
was washed with brine, dried over anhydrous Na2SO4 and concen-
trated in vacuo. The residue was purified by silica gel column chro-
matography (hexane/ethyl acetate = 4:1) to give the title compound
(2.27 g, 82%) as pale yellow oil. IR (neat) 1694, 1597, 1494, 1240,
1598, 1492, 1458, 1213, 1163, 1114, 759, 724 cmꢀ1 1H NMR
;
(CDCl3, 400 MHz) d 1.87–1.92 (2H, m), 2.32 (3H, s), 3.02 (2H, t,
J = 5.5 Hz), 3.07 (2H, t, J = 5.9 Hz), 3.12–3.17 (4H, m), 6.94 (1H, t,
J = 7.8 Hz), 7.07 (1H, d, J = 7.8 Hz), 7.12–7.17 (2H, m); HRMS m/z
calcd for C12H18N2 190.1470, found 190.1443.
5.1.18. 1-(m-Tolyl)-1,4-diazepane (5c)
The title compound was prepared from 4c in a similar manner
described for 5a. Yield: 100%; yellow liquid; IR (film) 2928, 1601,
1498, 1363, 1178, 765, 692 cmꢀ1 1H NMR (CDCl3, 400 MHz) d
;
1.86–1.91 (2H, m), 2.29 (3H, s), 2.82 (2H, t, J = 5.9 Hz), 3.02 (2H,
t, J = 5.5 Hz), 3.52–3.57 (4H, m), 6.47–6.51 (2H, m), 7.09 (2H, dd,
J = 9.4, 1.9 Hz); HRMS m/z calcd for C12H18N2 190.1470, found
190.1456.
1169, 928, 770 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 1.38, (4.5H,
;
s), 1.43, (4.5H, s), 1.92–1.99 (2H, m), 3.21–3.34 (2H, m), 3.54–3.78
(6H,m), 6.47–6.52 (2H, m), 7.38–7.42 (1H, m), 8.10–8.12 (1H, m);
MS (FAB) m/z: 278 [M+H]+.
5.1.19. 1-(p-Tolyl)-1,4-diazepane (5d)
The title compound was prepared from 4d in a similar manner
described for 5a. Yield: 100%; pale yellow oil; IR (film) 3318, 2923,
1618, 1520, 1394, 1363, 1189, 802 cmꢀ1
;
1H NMR (CDCl3,
5.1.14. tert-Butyl 4-(4-pyridyl)-1,4-diazepane-1-carboxylate (4m)
The title compound was prepared in a similar manner described
for 4l. Yield: 34%; pale yellow oil; mp 124–129 °C; IR (KBr) 1674,
400 MHz) d 1.87–1.92 (2H, m), 2.23 (3H, s), 2.79–2.85 (2H, m),
2.99–3.05 (2H, m), 3.49–3.58 (4H, m), 6.60 (2H, d, J = 8.2 Hz),
7.00 (2H, d, J = 8.2 Hz); MS (EI) m/z: 190 [M+].
1597, 1167, 987 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.36 (4.5H, s),
;
1.42 (4.5H, s), 1.92–1.99 (2H, m), 3.21–3.34 (2H, m), 3.52–3.69
(6H, m), 6.50 (2H, d, J = 6.5 Hz), 8.18–8.20 (2H, m); MS (EI) m/z:
277 [M+]; Anal. Calcd for C15H23N3O2: C, 64.95; H, 8.36; N, 15.15.
Found: C, 64.78; H, 8.46; N, 15.03.
5.1.20. 1-(4-Fluorophenyl)-1,4-diazepane (5e)
The title compound was prepared from 4e in a similar manner
described for 5a. Yield: 81%; pale yellow oil; IR (film) 3322, 2935,
1611, 1513, 1228, 814 cmꢀ1 1H NMR (CDCl3, 500 MHz) d 1.87–
;
1.92 (2H, m), 2.83 (2H, t, J = 5.9 Hz), 3.02 (2H, t, J = 5.5 Hz), 3.51
(2H, t, J = 5.5 Hz), 3.54 (2H, t, J = 5.9 Hz), 6.61 (2H, dd, J = 9.3,
4.4 Hz), 6.91 (2H, t, J = 9.3 Hz); MS (EI) m/z: 194 [M+].
5.1.15. 2-(1,4-Diazepan-1-yl)thiazole (4n)
2-Bromothiazole (8.20 g, 50.0 mmol) and homopiperazine
(10.0 g, 100 mmol) were stirred in 1-butanol (100 mL) under reflux

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1635
5.1.21. 1-(4-tert-Butylphenyl)-1,4-diazepane (5f)
m), 6.46–6.50 (2H, m), 7.38–7.42 (1H, m), 8.10–8.14 (1H, m); MS
The title compound was prepared from 4f in a similar manner
described for 5a. Yield: 97%; pale brown oil; IR (film) 2959, 1614,
(EI) m/z: 177 [M+].
1520, 1363, 1201, 812, 552 cmꢀ1
;
1H NMR (CDCl3, 400 MHz) d
5.1.28. 1-(4-Pyridyl)-1,4-diazepane (5m)
1.28 (9H, s), 1.87–1.92 (2H, m), 2.84 (2H, t, J = 5.9 Hz), 3.02 (2H,
t, J = 5.5 Hz), 3.52 (2H, t, J = 5.5 Hz), 3.54 (2H, t, J = 5.9 Hz), 6.63
(2H, d, J = 8.4 Hz), 7.21 (2H, d, J = 8.4 Hz); MS (EI) m/z: 232 [M+].
The title compound was prepared from 4m in a similar manner
described for 5a. Yield: 97%; pale yellow oil; IR (neat) 3270, 1600,
1518, 804 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.86–1.92 (2H, m),
;
2.83 (2H, t, J = 5.9 Hz), 3.02 (2H, t, J = 5.5 Hz), 3.53–3.61 (4H, m),
6.51 (2H, d, J = 6.6 Hz), 8.20 (2H, d, J = 6.6 Hz); MS (FAB) m/z: 178
[M+H]+.
5.1.22. 1-(4-Methoxyphenyl)-1,4-diazepane (5g)
The title compound was prepared from 4g in a similar manner
described for 5a. Yield: 100%; yellow liquid; IR (film) 2934, 1513,
1241, 1040, 814 cmꢀ1
;
1H NMR (CDCl3, 400 MHz) d 1.87–1.92
5.1.29. Benzyl 4-[4-(2,2,2-trifluoroacetyl)phenyl]-1,4-
diazepane-1-carboxylate (7)
(2H, m), 2.89 (2H, t, J = 5.9 Hz), 3.02 (2H, t, J = 5.5 Hz), 3.48–3.54
(4H, m), 3.75 (3H, s), 6.65 (2H, d, J = 9.0 Hz), 6.82 (2H, d,
The reaction was performed following the method described for
4i using 2,2,2,40-tetrafluoroacetophenone and benzyl 1-homopi-
perazinecarboxylate. Yield: 100%; pale yellow oil; IR (film) 2959,
J = 9.0 Hz); HRMS m/z calcd for
C12H18N2O 206.1419, found
206.1424.
1697, 1595, 1528, 1423, 1166 cmꢀ1 1H NMR (CDCl3, 500 MHz) d
;
5.1.23. 1-(4-Isopropoxyphenyl)-1,4-diazepane (5h)
1.93–2.06 (2H, m), 3.33–3.38 (1H, m), 3.40–3.46 (1H, m), 3.60–
3.74 (6H, m), 5.07 (1H, s), 5.13 (1H, s), 6.67–6.74 (2H, m), 7.25–
7.37 (5H, m), 7.91–7.98 (2H, m); MS (FAB) m/z: 407 [M+H]+.
The title compound was prepared from 4h in a similar manner
described for 5a. Yield: 89%; pale orange prism crystal; mp 62–
64 °C; IR (film) 2974, 2932, 1511, 1237, 1114, 957, 815 cmꢀ1 1H
;
NMR (CDCl3, 400 MHz) d 1.29 (6H, d, J = 5.9 Hz), 1.86–1.91 (2H,
m), 2.83 (2H, t, J = 5.9 Hz), 3.01 (2H, t, J = 5.5 Hz), 3.49 (2H, t,
J = 5.5 Hz), 3.52 (2H, t, J = 5.9 Hz), 4.33–4.37 (1H, m), 6.61 (2H, d,
J = 9.0 Hz), 6.79 (2H, d, J = 9.0 Hz); MS (EI) m/z: 234 [M+].
5.1.30. 4-{4-[(Benzyloxy)carbonyl]-1,4-diazepan-1-yl}benzoic
acid (8)
To a DMF (35 mL) solution of 7 (7.18 g, 17.7 mmol) was added
8 M aqueous solution of NaOH (4.40 mL, 35.2 mmol), and the mix-
ture was stirred at 80 °C for 1 h. After cooling to room temperature,
the mixture was diluted with water and washed with ethyl acetate.
The aqueous layer was made acidic with 1 M hydrochloric acid and
extracted with ethyl acetate. The extract was dried over MgSO4 and
concentrated in vacuo. The residue was triturated with diethyl
ether, and the deposited solid was filtered to give the title com-
pound (5.83 g, 93%) as colorless prism crystal. Mp 135–137 °C; IR
5.1.24. 4-(1,4-Diazepan-1-yl)benzonitrile (5i)
The title compound was prepared from 4i in a similar manner
described for 5a. Yield: 95%; pale yellow oil; IR (film) 2935, 2211,
1606, 1521, 1404, 1178, 817, 544 cmꢀ1
;
1H NMR (CDCl3,
400 MHz) d 1.85–1.90 (2H, m), 2.81 (2H, t, J = 5.9 Hz), 3.01 (2H, t,
J = 5.5 Hz), 3.55 (2H, t, J = 5.5 Hz), 3.61 (2H, t, J = 5.9 Hz), 6.65
(2H, t, J = 9.0 Hz), 8.43 (2H, d, J = 9.0 Hz); HRMS m/z calcd for
(KBr) 3063, 2947, 2667, 2562, 1699, 1667, 1600, 1417 cmꢀ1 1H
;
C
12H15N3 201.1266, found 201.1268.
NMR (CDCl3, 400 MHz) d 1.92–2.07 (2H, m), 3.30–3.36 (1H, m),
3.41 (1H, t, J = 5.9 Hz), 3.58–3.71 (6H, m), 5.08 (1H, s), 5.14 (1H,
s), 6.63–6.72 (2H, m), 7.24–7.38 (5H, m), 7.91–7.99 (2H, m); MS
(EI) m/z: 354 [M+].
5.1.25. Ethyl 4-(1,4-diazepan-1-yl)benzoate (5j)
The title compound was prepared from 4j in a similar manner
described for 5a. Yield: 74%; pale yellow oil; IR (film) 2976, 1697,
1605, 1522, 1415, 1364, 1281, 1183, 1108, 770 cmꢀ1
;
1H NMR
5.1.31. Benzyl 4-[4-(dimethylcarbamoyl)phenyl]-1,4-diazepane-
1-carboxylate (9a)
(CDCl3, 400 MHz) d 1.36 (3H, t, J = 7.0 Hz), 1.88–1.96 (2H, m),
2.79–2.87 (2H, m), 3.05 (2H, t, J = 5.5 Hz), 3.61 (2H, t, J = 5.5 Hz),
3.65 (2H, t, J = 5.9 Hz), 4.32 (2H, q, J = 7.0 Hz), 6.66 (2H, d,
J = 9.0 Hz), 7.89 (2H, d, J = 9.0 Hz); MS (EI) m/z: 248 [M+].
To a THF (80 mL) solution of 8 (7.09 g, 20.0 mmol) was added
1,10-carbonyldiimidazole (3.89 g, 24.0 mmol) under ice-cooling
and the mixture was stirred for 30 min. The reaction mixture
was warmed to room temperature, and a THF solution (2.0 M,
15.0 mL, 30.0 mmol) of dimethylamine was added. The mixture
was stirred for 30 min and diluted with saturated sodium hydro-
gen carbonate aqueous solution and extracted with ethyl acetate.
The extract was washed with brine, dried over anhydrous Na2SO4
and concentrated in vacuo. The residue was purified by silica gel
column chromatography (ethyl acetate) to give the title compound
(7.63 g, 100%) as pale yellow oil. IR (film) 3475, 2939, 1699, 1608,
1493, 1423, 1391 cmꢀ1; 1H NMR (CDCl3, 400 MHz) d 1.90–2.06 (2H,
m), 3.07 (6H, s), 3.26–3.33 (1H, m), 3.34–3.41 (1H, m), 3.52–3.70
(6H, m), 5.10 (1H, s), 5.14 (1H, s), 6.59–6.71 (2H, m), 7.22–7.42
(7H, m); MS (FAB) m/z: 382 [M+H]+.
5.1.26. 2-[4-(1,4-Diazepan-1-yl)phenyl]-N,N-dimethylacetamide
(5k)
A mixture of 4k (2.94 g, 7.43 mmol) and 10% Pd/C (H2O content:
50 wt %, 2.50 g) in ethanol (30 mL) was stirred at room tempera-
ture under hydrogen atmosphere for 1 h. After removal of Pd/C
by filtration, the filtrate was concentrated in vacuo to give the title
compound (1.83 g, 94%) as pale yellow oil. IR (film) 3430, 2934,
1629, 1520, 1398 cmꢀ1 1H NMR (CDCl3, 400 MHz) d 1.86–1.90
;
(2H, m), 2.79–2.84 (2H, m), 2.94 (3H, s), 2.97–3.04 (5H, m), 3.47
(2H, s), 3.49–3.57 (4H, m), 6.62 (2H, d, J = 9.0 Hz), 7.07 (2H, d,
J = 9.0 Hz); MS (FAB) m/z: 262 [M+H]+.
5.1.27. 1-(2-Pyridyl)-1,4-diazepane (5l)
5.1.32. Benzyl 4-[4-(methylcarbamoyl)phenyl]-1,4-diazepane-1-
carboxylate (9b)
To a CH2Cl2 (8.0 mL) solution of 4l (2.17 g, 7.80 mmol) was
added trifluoroacetic acid (8.0 mL) under ice-cooling. The reaction
mixture was stirred at room temperature for 3 h and concentrated
in vacuo. The residue was treated with 1 M aqueous solution of
NaOH and extracted with CH2Cl2. The extract was dried over anhy-
drous Na2SO4 and concentrated in vacuo to give the title com-
pound (1.34 g, 97%) as pale yellow oil. IR (neat) 3308, 1597,
The title compound was prepared from 8 in a similar manner
described for 9a. Yield: 100%; pale yellow oil; IR (film) 3336,
2944, 1694, 1607, 1513, 1423, 1231, 1120, 767 cmꢀ1 1H NMR
;
(CDCl3, 400 MHz) d 1.91–2.06 (2H, m), 2.99 (3H, d, J = 5.1 Hz),
3.28–3.34 (1H, m), 3.36–3.41 (1H, m), 3.55–3.70 (6H, m), 5.07
(1H, s), 5.13 (1H, s), 5.90–6.00 (1H, m), 6.63–6.71 (1H, m), 7.26–
7.39 (5H, m), 7.61–7.68 (2H, m), 7.91–7.96 (1H, m); MS (FAB) m/
z: 368 [M+H]+.
1496, 1440, 769 cmꢀ1
;
1H NMR (CDCl3, 400 MHz) d 1.86–1.92
(2H, m), 2.83–2.86 (2H, m), 3.01–3.04 (2H, m), 3.69–3.74 (4H,

1636
K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
5.1.33. 4-(1,4-Diazepan-1-yl)-N,N-dimethylbenzamide (10a)
The title compound was prepared from 9a in a similar manner
described for 5k. Yield: 94%; colorless oil; IR (film) 3444, 3321,
209 [M+]; Anal. Calcd for C10H15N3S: C, 57.38; H, 7.22; N, 20.08;
S, 15.32. Found: C, 57.27; H, 7.16; N, 20.03; S, 15.47.
2931, 1672, 1608, 1493, 1390 cmꢀ1
;
1H NMR (CDCl3, 400 MHz) d
5.1.40. (Z)-2-Cyano-3-morpholino-but-2-enethioamide (12g)
The title compound was prepared in a similar manner described
for 12b. Yield: 85%; pale yellow solid; mp 156–160 °C; IR (KBr)
1.85–1.94 (2H, m), 2.79–2.85 (2H, m), 3.00–3.05 (2H, m), 3.03–
3.10 (6H, m), 3.54–3.64 (4H, m), 6.66 (2H, d, J = 8.6 Hz), 7.36 (2H,
d, J = 8.6 Hz); MS (EI) m/z: 247 [M+].
3374, 3255, 3165, 2177, 1605, 1540, 1119, 985, 884 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 2.26 (3H, s), 3.36–3.39 (4H, m),
3.64–3.67 (4H, m), 8.38 (1H, br s), 9.06 (1H, br s); MS (FAB) m/z:
212 [M+H]+; Anal. Calcd for C9H13N3OS: C, 51.16; H, 6.20; N,
19.89; S, 15.18. Found: C, 51.15; H, 6.14; N, 19.73; S, 15.17.
5.1.34. 4-(1,4-Diazepan-1-yl)-N-methyl-benzamide (10b)
The title compound was prepared from 9b in a similar manner
described for 5k. Yield: 100%; colorless oil; IR (film) 3311, 2936,
1606, 1514, 1403, 1327, 1204, 829, 767 cmꢀ1 1H NMR (CDCl3,
;
5.1.41. (Z)-2-Cyano-3-(4-phenyl-1,4-diazepan-1-yl)but-2-
enethioamide (12k)
400 MHz) d 1.85–1.94 (2H, m), 2.82 (2H, t, J = 5.9 Hz), 2.98 (3H,
d, J = 4.7 Hz), 3.00–3.06 (2H, m), 3.53–3.67 (4H, m), 5.90–6.03
(1H, m), 6.67 (2H, d, J = 9.0 Hz), 7.64 (2H, d, J = 9.0 Hz); MS (EI)
m/z: 233 [M+].
The title compound was prepared from 5a in a similar manner
described for 12b. Yield: 85%; pale yellow solid; mp 151–153 °C;
IR (KBr) 3290, 2185, 1599, 1538, 1503, 1397, 1369, 1011, 873,
754 cmꢀ1 1H NMR (DMSO-d6, 500 MHz) d 1.91–1.96 (2H, m),
;
5.1.35. (Z)-2-Cyano-3-(dimethylamino)but-2-enethioamide
(12a)
2.23 (3H, s), 3.50–3.55 (4H, m), 3.61–3.63 (2H, m), 3.71–3.73
(2H, m), 6.61 (1H, t, J = 7.3 Hz), 6.76 (2H, d, J = 7.3 Hz), 7.16 (2H,
t, J = 7.3 Hz), 8.33 (1H, br s), 9.00 (1H, br s); HRMS m/z calcd for
2-Cyanothioacetamide (1.00 g, 10.0 mmol) and N,N-dimethyl-
acetamide dimethylacetal (1.73 g, 13.0 mmol) were stirred in ace-
tonitrile (5.0 mL) at room temperature for 1 h. The deposited solid
was filtered and washed with acetonitrile to give the title com-
pound (1.05 g, 62%) as pale yellow solid. Mp 155–158 °C; 1H
NMR (DMSO-d6, 400 MHz) d 2.27 (3H, s), 3.03 (6H, s), 8.08 (1H,
br s), 8.83 (1H, br s).
C16H21N4S 301.1487, found 301.1465; Anal. Calcd for C16H20N4S:
C, 63.97; H, 6.71; N, 18.65; S, 10.67. Found: C, 63.76; H, 6.47; N,
18.75; S, 10.62.
5.1.42. (Z)-2-Cyano-3-[4-(o-tolyl)-1,4-diazepan-1-yl]but-2-
enethioamide (12l)
The title compound was prepared from 5b in a similar manner
described for 12b. Yield: 55%; pale yellow solid; mp 99–100 °C; IR
(KBr) 3286, 3173, 2184, 1599, 1521, 1410, 1294, 1220, 881,
5.1.36. (Z)-2-Cyano-3-(propylamino)but-2-enethioamide (12b)
(Z)-2-Cyano-3-ethoxybut-2-enethioamide12 (0.340 g, 2.00 mmol)
and propylamine (0.158 g, 2.50 mmol) were suspended in ethanol
(5.0 mL) and the mixture was stirred at room temperature for 15 h.
The deposited solid was filtered and washed with ethanol to give
the title compound (0.289 g, 79%) as pale yellow solid. Mp 149–
765 cmꢀ1 1H NMR (DMSO-d6, 500 MHz) d 2.00–2.04 (2H, m),
;
2.24 (3H, s), 2.36 (3H, s), 3.01 (2H, t, J = 5.4 Hz), 3.16–3.17 (2H,
m), 3.66 (2H, t, J = 5.4 Hz), 3.70–3.72 (2H, m), 6.95 (1H, t,
J = 6.8 Hz), 7.07 (1H, d, J = 7.3 Hz), 7.12–7.17 (2H, m), 8.27 (1H, br
s), 8.93 (1H, br s); HRMS m/z calcd for C17H23N4S 315.1644, found
315.1643; Anal. Calcd for C17H22N4Sꢁ0.56H2O: C, 62.92; H, 7.18; N,
17.26; S, 9.88. Found: C, 62.65; H, 6.88; N, 17.11; S, 9.13.
151 °C; IR (KBr) 3400, 3287, 3187, 2190, 1612 cmꢀ1 1H NMR
;
(DMSO-d6, 400 MHz) d 0.97 (3H, t, J = 7.4 Hz), 1.55–1.64 (2H, m),
2.30 (3H, s), 3.35–3.40 (2H, m), 7.65 (1H, br s), 8.45 (1H, br s),
12.74 (1H, br s); MS (FAB) m/z: 184 [M+H]+; Anal. Calcd for
C8H13N3S: C, 52.43; H, 7.15; N, 22.93; S, 17.49. Found: C, 52.59; H,
7.25; N, 22.83; S, 17.51.
5.1.43. (Z)-2-Cyano-3-[4-(m-tolyl)-1,4-diazepan-1-yl]but-2-
enethioamide (12m)
The title compound was prepared from 5c in a similar manner
described for 12b. Yield: 62%; pale yellow solid; mp 144–148 °C;
5.1.37. (Z)-2-Cyano-3-(cyclohexylamino)but-2-enethioamide
(12c)
IR (KBr) 3151, 2188, 1601, 1542, 1345, 1174, 912, 766 cmꢀ1 1H
;
The title compound was prepared in a similar manner described
for 12b. Yield: 76%; pale yellow solid; mp 142–144 °C; IR (KBr)
NMR (DMSO-d6, 400 MHz) d 1.91–1.95 (2H, m), 2.22 (3H, s), 2.23
(3H, s), 3.48–3.54 (4H, m), 3.60–3.63 (2H, m), 3.68–3.71 (2H, m),
6.44 (1H, d, J = 7.0 Hz), 6.55–6.57 (2H, m), 7.03 (1H, t, J = 7.0 Hz),
8.34 (1H, br s), 9.01 (1H, br s); HRMS m/z calcd for C17H23N4S
315.1644, found 315.1645; Anal. Calcd for C17H22N4S: C, 64.93;
H, 7.05; N, 17.82; S, 10.20. Found: C, 64.65; H, 7.05; N, 17.73; S,
10.13.
3412, 3297, 3188, 2187, 1613, 1493, 1410 cmꢀ1
;
1H NMR
(DMSO-d6, 400 MHz) d 1.33–1.61 (6H, m), 1.81–1.93 (4H, m),
2.37 (3H, s), 3.55–3.64 (1H, m), 6.38 (1H, br s), 6.69 (1H, br s),
12.92 (1H, br s); MS (EI) m/z: 223 [M+].
5.1.38. (Z)-2-Cyano-3-(dipropylamino)but-2-enethioamide
(12d)
5.1.44. (Z)-2-Cyano-3-[4-(4-fluorophenyl)-1,4-diazepan-1-
yl]but-2-enethioamide (12o)
The title compound was prepared in a similar manner described
for 12b. Yield: 44%; pale yellow solid; IR (KBr) 3370, 3290, 3201,
The title compound was prepared from 5e in a similar manner
described for 12b. Yield: 30%; pale yellow solid; mp 150–152 °C;
2172, 1627, 1544, 1500, 867 cmꢀ1 1H NMR (DMSO-d6, 400 MHz)
;
IR (KBr) 3356, 3269, 3178, 2177, 1615, 1537, 1507 cmꢀ1 1H NMR
;
d 0.85 (6H, t, J = 7.4 Hz), 1.55–1.64 (4H, m), 2.30 (3H, s), 3.37–
3.40 (4H, m), 8.36 (1H, br s), 8.96 (1H, br s); MS (EI) m/z: 225
[M+]; Anal. Calcd for C11H19N3S: C, 58.63; H, 8.50; N, 18.65; S,
14.23. Found: C, 58.58; H, 8.44; N, 18.62; S, 13.96.
(DMSO-d6, 400 MHz) d 1.89–1.98 (2H, m), 2.23 (3H, s), 3.47–3.54
(4H, m), 3.57–3.63 (2H, m), 3.66–3.72 (2H, m), 6.74 (2H, dd,
J = 9.0, 4.3 Hz), 6.97 (2H, t, J = 9.0 Hz), 8.31 (1H, br s), 8.96 (1H, br
s); MS (FAB) m/z: 319 [M+H]+; Anal. Calcd for C16H19FN4Sꢁ0.4H2O:
C, 59.02; H, 6.13; N, 17.21. Found: C, 58.73; H, 5.84; N, 17.20.
5.1.39. (Z)-2-Cyano-3-piperidin-1-yl-but-2-enethioamide (12f)
The title compound was prepared in a similar manner described
for 12b. Yield: 65%; pale yellow solid; mp 161–166 °C; IR (KBr)
5.1.45. (Z)-2-Cyano-3-[4-(4-methoxyphenyl)-1,4-diazepan-1-
yl]but-2-enethioamide (12q)
3381, 3268, 3170, 2182, 1600, 1534, 873, 838, 636 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 1.58–1.63 (6H, m), 2.27 (3H, s),
3.31–3.36 (4H, m), 8.15 (1H, br s), 8.86 (1H, br s); MS (EI) m/z:
The title compound was prepared from 5g in a similar manner
described for 12b. Yield: 64%; pale yellow solid; mp 157–158 °C;

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1637
IR (KBr) 3284, 3154, 2179, 1512, 1361, 1243, 1037, 821 cmꢀ1
;
1H
5.1.51. 4-(4-Phenyl-1,4-diazepan-1-yl)-2-thioxo-1,2-
dihydropyridine-3-carbonitrile (14k)
NMR (DMSO-d6, 400 MHz) d 1.89–1.96 (2H, m), 2.24 (3H, s), 3.44
(2H, t, J = 5.9 Hz), 3.49 (2H, t, J = 5.9 Hz), 3.57–3.63 (4H, m), 3.64
(3H, s), 6.70 (2H, d, J = 9.0 Hz), 6.76 (2H, d, J = 9.0 Hz), 8.27 (1H,
br s), 8.95 (1H, br s); HRMS m/z calcd for C17H23N4OS 331.1593,
found 331.1589; Anal. Calcd for C17H22N4OS: C, 61.79; H, 6.71; N,
16.95; S, 9.70. Found: C, 61.51; H, 6.69; N, 16.99; S, 9.71.
The title compound was prepared from 12k in a similar manner
described for 14a. Yield: 84%; pale yellow solid; mp 128–132 °C; IR
(KBr) 2954, 2205, 1626, 1504, 1248, 1136, 928, 750, 617 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 1.90–1.96 (2H, m), 3.51 (2H, t,
J = 5.9 Hz), 3.71 (4H, q, J = 5.9 Hz), 3.93 (2H, t, J = 5.9 Hz), 6.40
(1H, d, J = 7.4 Hz), 6.56 (1H, t, J = 7.1 Hz), 6.74 (2H, d, J = 7.1 Hz),
7.12 (2H, t, J = 7.1 Hz), 7.83 (1H, d, J = 7.4 Hz), 12.47 (1H, br s);
HRMS m/z calcd for C17H18N4S 310.1252, found 310.1224; Anal.
Calcd for C17H18N4S: C, 65.78; H, 5.84; N, 18.05; S, 10.33. Found:
C, 65.58; H, 5.51; N, 18.03; S, 10.24.
5.1.46. (Z)-2-Cyano-3-[4-(4-cyanophenyl)-1,4-diazepan-1-
yl]but-2-enethioamide (12s)
The title compound was prepared from 5i in a similar manner
described for 12b. Yield: 58%; pale yellow solid; mp 169–171 °C;
IR (KBr) 3290, 2214, 217, 1604, 1519, 1408, 1179, 819, 543 cmꢀ1
;
1H NMR (DMSO-d6, 400 MHz) d 1.88–1.94 (2H, m), 2.21 (3H, s),
3.52 (2H, t, J = 5.5 Hz), 3.58–3.63 (4H, m), 3.82 (2H, t, J = 5.5 Hz),
6.85 (2H, d, J = 9.0 Hz), 7.51 (2H, d, J = 9.0 Hz), 8.38 (1H, br s),
9.02 (1H, br s); HRMS m/z calcd for C17H20N5S 326.1440, found
326.1436.
5.1.52. 4-[4-(p-Tolyl)-1,4-diazepan-1-yl]-2-thioxo-1,2-
dihydropyridine-3-carbonitrile (14n)
Compound 5d (463 mg, 2.39 mmol) and (2Z)-2-cyano-3-eth-
oxybut-2-enethioamide (386 mg, 2.27 mmol) were stirred in
DMF (4.8 mL) at room temperature for 30 min. Subsequently,
N,N-dimethylformamide dimethylacetal (0.302 mL, 2.27 mmol)
was added to the mixture. The mixture was stirred at room tem-
perature for 30 min, and then warmed to 60 °C and stirred for
1 h. After cooling to room temperature, ethyl acetate (10 mL) and
water (50 mL) were added to the mixture, and the deposited solid
was filtered and washed with ethyl acetate and water to give the
title compound (125 mg, 28%) as a pale brown solid. Mp 220–
223 °C; IR (KBr) 3115, 2940, 2205, 1626, 1518, 1250, 928, 798,
5.1.47. (Z)-2-Cyano-3-[4-(2-pyridyl)-1,4-diazepan-1-yl]but-2-
enethioamide (12x)
The title compound was prepared from 5l in a similar manner
described for 12b. Yield: 79%; pale yellow solid; mp 155–157 °C;
IR (KBr) 3398, 3288, 3184, 2185, 1598, 1540, 1494, 1439,
773 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 1.88–1.94 (2H, m),
,
2.24 (3H, s), 3.55–3.70 (6H, m), 3.89–3.92 (2H, m), 6.57 (1H, dd,
J = 7.0, 5.0 Hz), 6.72 (1H, d, J = 8.6 Hz), 7.50 (1H, ddd, J = 8.6, 7.0,
2.0 Hz), 8.07 (1H, dd, J = 5.0, 2.0 Hz), 8.34 (1H, br s), 9.01 (1H, br
s); MS (FAB) m/z: 302 [M+H]+; Anal. Calcd for C15H19N5S: C,
59.77; H, 6.35; N, 23.24; S, 10.64. Found: C, 59.38; H, 6.34; N,
22.99; S, 10.53.
775 cmꢀ1 1H NMR (CDCl3, 500 MHz) d 2.08–2.13 (2H, m), 2.25
;
(3H, s), 3.56 (2H, t, J = 5.9 Hz), 3.71–3.76 (2H, m), 3.76–3.80 (2H,
m), 4.10–4.15 (2H, m), 6.19 (1H, d, J = 7.8 Hz), 6.65 (2H, d,
J = 8.2 Hz), 7.05 (2H, d, J = 8.2 Hz), 7.20 (1H, d, J = 7.8 Hz), 11.22
(1H, br s); MS (EI) m/z: 324 [M+]; Anal. Calcd for C18H20N4Sꢁ0.1H2O:
C, 66.27; H, 6.24; N, 17.17; S, 9.83. Found: C, 66.07; H, 6.19; N,
17.10; S, 9.60.
5.1.48. (Z)-2-Cyano-3-[4-(4-pyridyl)-1,4-diazepan-1-yl]but-2-
enethioamide (12y)
5.1.53. 4-[4-(4-tert-Butylphenyl)-1,4-diazepan-1-yl]-2-thioxo-
1,2-dihydropyridine-3-carbonitrile (14p)
The title compound was prepared from 5m in a similar manner
described for 12b. Yield: 57%; pale yellow solid; IR (KBr) 3172,
2185, 1600, 1538, 1520, 1411 cmꢀ1
;
1H NMR (DMSO-d6,
The title compound was prepared from 5f in a similar manner
described for 14n. Yield: 21%; pale brown solid; mp 257–258 °C;
400 MHz) d 1.89–1.94 (2H, m), 2.23 (3H, s), 3.52–3.62 (6H, m),
3.78–3.80 (2H, m), 6.70 (2H, d, J = 6.7 Hz), 8.09 (2H, d, J = 6.7 Hz),
8.41 (1H, br s), 9.04 (1H, br s); MS (FAB) m/z: 302 [M+H]+.
IR (KBr) 3121, 3041, 2958, 2205, 1625, 1519, 1459, 1247 cmꢀ1
;
1H NMR (CDCl3, 400 MHz) d 1.28 (9H, s), 2.12 (2H, m), 3.56 (2H,
t, J = 5.9 Hz), 3.71–3.81 (4H, m), 4.13 (2H, t, J = 5.1 Hz), 6.20 (1H,
d, J = 7.6 Hz), 6.66 (2H, d, J = 8.6 Hz), 7.22 (1H, d, J = 7.6 Hz), 7.24
(2H, d, J = 8.6 Hz), 11.94 (1H, br s); MS (EI) m/z: 366 [M+].
5.1.49. (Z)-2-Cyano-3-(4-thiazol-2-yl-1,4-diazepan-1-yl)but-2-
enethioamide (12z)
The title compound was prepared from 4n in a similar manner
described for 12b. Yield: 91%; pale yellow solid; mp 149–152 °C; IR
5.1.54. 4-[4-(4-Isopropoxyphenyl)-1,4-diazepan-1-yl]-2-thioxo-
1,2-dihydropyridine-3-carbonitrile (14r)
(KBr) 3276, 3130, 2182, 1531, 885, 615 cmꢀ1 1H NMR (DMSO-d6,
;
The title compound was prepared from 5h in a similar manner
described for 14n. Yield: 32%; pale brown solid; mp 216–218 °C; IR
400 MHz) d 1.95–2.00 (2H, m), 2.27 (3H, s), 3.57–3.69 (6H, m),
3.80–3.84 (2H, m), 6.77 (1H, d, J = 3.5 Hz), 7.12 (1H, d, J = 3.5 Hz),
8.42 (1H, br s), 9.06 (1H, br s); MS (FAB) m/z: 308 [M+H]+; Anal.
Calcd for C13H17N5S2: C, 50.79; H, 5.57; N, 22.78; S, 20.86. Found:
C, 50.52; H, 5.64; N, 22.44; S, 21.10.
(KBr) 3440, 3128, 3046, 2974, 2205, 1625, 1511, 1241 cmꢀ1 1H
;
NMR (CDCl3, 500 MHz) d 1.30 (6H, d, J = 5.9 Hz), 2.08–2.14 (2H,
m), 3.51 (2H, t, J = 5.9 Hz), 3.73 (2H, t, J = 5.4 Hz), 3.76 (2H, t,
J = 5.9 Hz), 4.12 (2H, t, J = 5.4 Hz), 4.37–4.42 (1H, m), 6.21 (1H, d,
J = 7.8 Hz), 6.67 (2H, d, J = 8.8 Hz), 6.82 (2H, d, J = 8.8 Hz), 7.23
(1H, d, J = 7.8 Hz), 11.84 (1H, br s); MS (EI) m/z: 368 [M+]; Anal.
Calcd for C20H24N4OSꢁ0.15H2O: C, 64.71; H, 6.60; N, 15.09; S,
8.64. Found: C, 64.59; H, 6.46; N, 15.09; S, 8.47.
5.1.50. 4-(Dimethylamino)-2-thioxo-1,2-dihydropyridine-3-
carbonitrile (14a)
Compound 12a (1.05 g, 6.20 mmol) and N,N-dimethylformam-
ide dimethylacetal (2.22 g, 18.6 mmol) were stirred in toluene
(10 mL) under reflux for 2 h, and then cooled to room temperature.
The mixture was concentrated in vacuo. The residue was sus-
pended in 1 M aqueous solution of NaOH (10 mL) and stirred under
reflux for 30 min. After cooling to room temperature, 1 M hydro-
chloric acid (15 mL) was added. The deposited solid was filtered
and washed with water and ethanol to give the title compound
(0.871 g, 78%) as pale yellow solid. Mp 246–250 °C; 1H NMR
(DMSO-d6, 400 MHz) d 3.12 (6H, s), 6.25 (1H, d, J = 7.3 Hz), 7.29–
7.33 (1H, m), 12.40 (1H, br s).
5.1.55. Ethyl 4-[4-(3-cyano-2-thioxo-1,2-dihydropyridin-4-yl)-
1,4-diazepan-1-yl]benzoate (14t)
The title compound was prepared from 5j in a similar manner
described for 14n. Yield: 28%; pale brown solid; mp 202–204 °C;
IR (KBr) 3120, 2972, 2205, 1697, 1623, 1604, 1519, 1285, 1240,
1186, 768 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 1.27 (3H, t,
;
J = 7.0 Hz), 1.88–1.99 (2H, m), 3.57–3.64 (2H, m), 3.70–3.77 (2H,
m), 3.79–3.85 (2H, m), 3.93–3.99 (2H, m), 4.20 (2H, q, J = 7.0 Hz),
6.42 (1H, d, J = 7.8 Hz), 6.83 (2H, d, J = 9.0 Hz), 7.34 (1H, d,

1638
K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
J = 7.8 Hz), 7.72 (2H, d, J = 9.0 Hz), 12.53 (1H, br s); MS (FAB) m/z:
383 [M+H]+; Anal. Calcd for C20H22N4O2Sꢁ0.12H2O: C, 62.45; H,
5.83; N, 14.57; S, 8.34. Found: C, 62.22; H, 5.72; N, 14.65; S, 8.51.
stirred at room temperature for 1 h, and water (3.0 mL) was added.
The deposited solid was filtered and washed with water and etha-
nol to give the title compound (0.106 g, 27%) as pale yellow solid.
Mp 214–215 °C; IR (KBr) 3348, 3319, 3189, 1650, 1592, 1504,
5.1.56. 4-[4-(3-Cyano-2-thioxo-1,2-dihydropyridin-4-yl)-1,4-
diazepan-1-yl]-N,N-dimethyl benzamide (14u)
1364 cmꢀ1 1H NMR (DMSO-d6, 400 MHz)
; d 0.95 (3H, t,
J = 7.4 Hz), 1.59–1.68 (2H, m), 3.16–3.21 (2H, m), 6.41 (1H, d,
J = 5.6 Hz), 6.44 (1H, t, J = 5.4 Hz), 6.81 (2H, br s), 7.02 (2H, br s),
The title compound was prepared from 10a in a similar manner
described for 14n. Yield: 24%; pale brown solid; mp 239–241 °C; IR
8.05 (1H, d, J = 5.6 Hz); HRMS m/z calcd for
C11H15N4OS
(KBr) 3180, 3147, 3045, 2960, 2918, 2208, 1605, 1525 cmꢀ1
;
1H
251.0967, found 251.0968; Anal. Calcd for C11H14N4OSꢁ1.1H2O: C,
48.91; H, 6.04; N, 20.74; S, 11.87. Found: C, 49.06; H, 5.92; N,
20.71; S, 11.90.
NMR (DMSO-d6, 500 MHz) d 1.92–2.00 (2H, m), 2.94 (6H, s),
3.54–3.61 (2H, m), 3.71–3.81 (4H, m), 3.95–4.01 (2H, m), 6.44
(1H, d, J = 7.8 Hz), 6.79 (2H, d, J = 8.8 Hz), 7.26 (2H, d, J = 8.8 Hz),
7.36 (1H, d, J = 7.8 Hz), 12.50 (1H, br s); MS (FAB) m/z: 382
[M+H]+; Anal. Calcd for C20H23N5OSꢁ0.6H2O: C, 61.23; H, 6.22; N,
17.85; S, 8.17. Found: C, 61.32; H, 6.18; N, 17.95; S, 8.12.
5.1.61. 3-Amino-4-(cyclohexylamino)thieno[2,3-b]pyridine-2-
carboxamide (15c)
The title compound was prepared from 12c in a similar manner
described for 15b. Yield: 14%; pale yellow solid; mp 244–247 °C; IR
(KBr) 3141, 1664, 1598, 1513, 1497, 1108 cmꢀ1 1H NMR (DMSO-
;
5.1.57. 4-[4-(3-Cyano-2-thioxo-1,2-dihydropyridin-4-yl)-1,4-
diazepan-1-yl]-N-methyl-benzamide (14v)
d6, 400 MHz) d 1.20–1.98 (10H, m), 3.43–3.50 (1H, m), 6.16 (1H,
d, J = 7.5 Hz), 6.46 (1H, d, J = 5.7 Hz), 6.71 (2H, br s), 7.08 (2H, br
s), 8.06 (1H, d, J = 5.7 Hz); HRMS m/z calcd for C14H19N4OS
291.1280, found 291.1284; Anal. Calcd for C14H18N4OSꢁ0.3H2O: C,
56.85; H, 6.34; N, 18.94; S, 10.85. Found: C, 57.00; H, 6.27; N,
18.95; S, 10.61.
The title compound was prepared from 10b in a similar manner
described for 14n. Yield: 30%; pale brown solid; IR (KBr) 3340,
2940, 2206, 1606, 1510, 1301, 1241, 766 cmꢀ1 1H NMR (DMSO-
;
d6, 400 MHz) d 1.90–1.99 (2H, m), 2.72 (3H, d, J = 3.5 Hz), 3.55–
3.62 (2H, m), 3.70–3.77 (2H, m), 3.78–3.84 (2H, m), 3.93–4.00
(2H, m), 6.44 (1H, d, J = 7.8 Hz), 6.80 (2H, d, J = 8.2 Hz), 7.36 (1H,
d, J = 7.8 Hz), 7.66 (2H, d, J = 8.2 Hz), 8.01 (1H, br s), 12.55 (1H, br
s); MS (FAB) m/z: 368 [M+H]+.
5.1.62. 3-Amino-4-(dipropylamino)thieno[2,3-b]pyridine-2-
carboxamide (15d)
5.1.58. 2-{4-[4-(3-Cyano-2-thioxo-1,2-dihydropyridin-4-yl)-1,4-
diazepan-1-yl]phenyl}-N,N-dimethylacetamide (14w)
The title compound was prepared from 12d in a similar manner
described for 15b. Yield: 23%; pale yellow solid; mp 126–128 °C; IR
(KBr) 3419, 3320, 3160, 2960, 1650, 1578, 1499, 1459, 1372,
The title compound was prepared from 5k in a similar manner
described for 14n. Yield: 47%; pale brown solid; IR (KBr) 3124,
993 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 0.79 (6H, t, J = 7.4 Hz),
;
3034, 2938, 2203, 1616, 1519 cmꢀ1 1H NMR (CDCl3, 400 MHz) d
;
1.39–1.48 (4H, m), 3.10 (4H, t, J = 7.4 Hz), 7.06 (4H, br s), 7.11
(1H, d, J = 5.5 Hz), 8.39 (1H, d, J = 5.5 Hz); HRMS m/z calcd for
2.04–2.16 (2H, m), 2.96 (3H, s), 3.02 (3H, s), 3.52–3.63 (4H, m),
3.69–3.82 (4H, m), 4.08–4.16 (2H, m), 6.19 (1H, d, J = 7.8 Hz),
6.66 (2H, d, J = 8.6 Hz), 7.12 (2H, d, J = 8.6 Hz), 7.22 (1H, d,
J = 7.8 Hz), 11.94 (1H, br s); MS (FAB) m/z: 396 [M+H]+.
C14H21N4OS 293.1436, found 293.1440; Anal. Calcd for
C
14H20N4OSꢁ0.1H2O: C, 57.16; H, 6.92; N, 19.04; S, 10.90. Found:
C, 57.13; H, 6.60; N, 19.17; S, 11.10.
5.1.59. 3-Amino-4-(dimethylamino)thieno[2,3-b]pyridine-2-
carboxamide (1)
5.1.63. 3-Amino-4-pyrrolidin-1-yl thieno[2,3-b]pyridine-2-
carboxamide (15e)
To a DMF (10 mL) solution of 14a (870 mg, 4.86 mmol) were
added 8 M aqueous solution of NaOH (2.00 mL) and 2-chloroacet-
amide (542 mg, 5.80 mmol), and the mixture was stirred at room
temperature for 1 h. Water (10 mL) was added to the mixture,
and the deposited solid was filtered and washed with water and
ethanol to give the title compound (790 mg, 69%) as pale yellow
solid. Mp 208–211 °C; IR (KBr) 3430, 3296, 3132, 1673, 1582,
(Z)-2-Cyano-3-ethoxybut-2-enethioamide (0.170 g, 1.00 mmol)
and pyrrolidine (0.085 g, 1.20 mmol) in ethanol (3.0 mL) were stir-
red at room temperature for 18 h. The deposited solid was filtered
and washed with ethanol to give a crude solid (0.18 g) of (Z)-2-cy-
ano-3-pyrrolidin-1-yl-but-2-enethioamide (12e). The obtained so-
lid and N,N-dimethylformamide dimethylacetal (0.358 g,
3.00 mmol) were stirred in toluene (2 mL) under reflux for 2 h,
and then cooled to room temperature. The mixture was concen-
trated in vacuo. The residue was suspended in 1 M aqueous solu-
tion of NaOH (2 mL) and stirred under reflux for 30 min. After
cooling to room temperature, 1 M hydrochloric acid (3 mL) was
added. The deposited solid was filtered and washed with water
and ethanol to give a crude solid (0.15 g) of 4-pyrrolidin-1-yl-2-
thioxo-1,2-dihydropyridine-3-carbonitrile (14e). The obtained so-
lid was dissolved in DMF (2.0 mL), and 8 M aqueous solution of
NaOH (0.41 mL) and 2-chloroacetamide (93 mg, 1.00 mmol) were
added. The mixture was stirred at room temperature for 1 h, and
water (2.0 mL) was added. The deposited solid was filtered and
washed with water and ethanol to give the title compound
(0.150 g, 58%) as pale yellow solid. Mp 275–283 °C; IR (KBr)
3429, 3297, 3138, 2999, 2877, 1673, 1611, 1584, 1503, 1372,
1372, 979 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 2.80 (6H, s),
;
6.96 (1H, d, J = 5.5 Hz), 6.97 (2H, br s), 7.04 (2H, br s), 8.36 (1H,
d, J = 5.5 Hz); MS (FAB) m/z: 237 [M+H]+; Anal. Calcd for
C10H12N4OS: C, 50.83; H, 5.12; N, 23.71; S, 13.57. Found: C,
50.70; H, 4.98; N, 23.53; S, 13.38.
5.1.60. 3-Amino-4-(propylamino)thieno[2,3-b]pyridine-2-
carboxamide (15b)
Compound 12b (290 mg, 1.58 mmol) and N,N-dimethylform-
amide dimethylacetal (0.630 mL, 4.74 mmol) were stirred in tolu-
ene (3.0 mL) under reflux for 2 h. The reaction mixture was
cooled to room temperature and concentrated in vacuo. The resi-
due was suspended in 1 M aqueous solution of NaOH (10 mL)
and stirred under reflux for 30 min. After cooling to room temper-
ature, 1 M hydrochloric acid (15 mL) was added, and the deposited
solid was filtered and washed with water and ethanol to give a
crude solid (0.17 g) of 4-(propylamino)-2-thioxo-1H-pyridine-3-
carbonitrile (14b). The obtained solid was dissolved in DMF
(3.0 mL), and 8 M aqueous solution of NaOH (0.50 mL) and 2-chlo-
roacetamide (103 mg, 1.10 mmol) were added. The mixture was
1341, 1273, 1113, 1056, 1002, 618, 486 cmꢀ1 1H NMR (DMSO-
;
d6, 400 MHz) d 1.91 (4H, s), 3.30 (4H, s), 6.87 (1H, d, J = 5.8 Hz),
6.88 (2H, s), 7.02 (2H, br s), 8.26 (1H, d, J = 5.8 Hz); MS (FAB) m/
z: 263 [M+H]+; Anal. Calcd for C12H14N4OS: C, 54.94; H, 5.38; N,
21.36; S, 12.22. Found: C, 54.54; H, 5.15; N, 21.10; S, 12.03.

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1639
5.1.64. 3-Amino-4-(1-piperidyl)thieno[2,3-b]pyridine-2-
carboxamide (15f)
694 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 2.10–2.15 (2H, m),
;
3.16–3.19 (2H, m), 3.26–3.29 (2H, m), 3.52 (2H, t, J = 6.3 Hz), 3.75
(2H, t, J = 6.3 Hz), 6.58 (1H, t, J = 8.2 Hz), 6.74 (2H, d, J = 8.2 Hz),
6.95 (2H, br s), 7.05 (1H, d, J = 5.5 Hz), 7.05 (2H, br s), 7.14 (2H, t,
J = 8.2 Hz), 8.36 (1H, d, J = 5.5 Hz); HRMS m/z calcd for C19H21N5OS
367.1467, found 367.1462; Anal. Calcd for C19H21N5OSꢁ0.24H2O: C,
61.38; H, 5.82; N, 18.84; S, 8.62. Found: C, 61.22; H, 5.64; N, 18.94;
S, 8.49.
The title compound was prepared from 12f in a similar manner
described for 15b. Yield: 38%; pale yellow solid; mp 191–192 °C; IR
(KBr) 3460, 3329, 3176, 1651, 1589, 1501, 1378, 963 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 1.72–1.79 (6H, m), 2.55–3.40 (4H,
m), 6.93 (2H, br s), 6.99 (1H, d, J = 5.1 Hz), 7.07 (2H, br s), 8.40
(1H, d, J = 5.1 Hz); HRMS m/z calcd for C13H17N4OS 277.1123, found
277.1123; Anal. Calcd for C13H16N4OSꢁ0.5H2O: C, 54.72; H, 6.00; N,
19.63; S, 11.24. Found: C, 54.68; H, 6.03; N, 19.67; S, 11.05.
5.1.70. 3-Amino-4-[4-(o-tolyl)-1,4-diazepan-1-yl]thieno[2,3-
b]pyridine-2-carboxamide (15l)
5.1.65. 3-Amino-4-morpholino-thieno[2,3-b]pyridine-2-
carboxamide (15g)
Compound 12l (0.220 g, 0.700 mmol) and N,N-dimethylform-
amide dimethylacetal (0.186 mL, 1.40 mmol) were stirred in etha-
nol (5.0 mL) at room temperature for 1 h, and the mixture was
concentrated in vacuo. The residue was dissolved in N,N-dimethyl-
acetamide (1.4 mL), and the mixture was stirred at 80 °C for 1 h.
After cooling to room temperature, 8 M aqueous solution of NaOH
(0.30 mL) and 2-chloroacetamide (80.0 mg, 0.856 mmol) were
added. After the mixture was stirred at room temperature for 1 h,
water was added to the mixture, and the deposited solid was filtered
and washed with water and ethanol to give the title compound
(0.184 g, 69%) as pale yellow solid. Mp 206–209 °C (decomposition);
IR (KBr) 3427, 3308, 3142, 1583, 1493, 1374, 1228, 1053, 944,
4-(Dimethoxymethyl)morpholine16 was used in place of N,N-
dimethylformamide dimethylacetal and the title compound was
prepared from 12g in a similar manner described for 15b. Yield:
28%; pale yellow solid; mp 232–234 °C; IR (KBr) 3427, 3377,
3170, 1670, 1579, 1501, 1373, 1112, 969 cmꢀ1 1H NMR (DMSO-
;
d6, 400 MHz) d 2.90–3.15 (4H, m), 3.84–3.86 (4H, m), 6.95 (2H,
br s), 7.05 (1H, d, J = 5.3 Hz), 7.13 (2H, br s), 8.46 (1H, d,
J = 5.3 Hz); HRMS m/z calcd for C12H15N4O2S 279.0916, found
279.0924; Anal. Calcd for C12H14N4O2Sꢁ0.3H2O: C, 50.80; H, 5.19;
N, 19.75; S, 11.30. Found: C, 50.95; H, 4.86; N, 19.72; S, 11.28.
767 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 1.97–2.04 (2H, m), 2.23
;
5.1.66. tert-Butyl 4-[3-amino-2-(aminocarbonyl)thieno[2,3-
b]pyridin-4-yl]piperazine-1-carboxylate (15h)
(3H, s), 3.11 (2H, t, J = 5.9 Hz), 3.22–3.25 (2H, m), 3.38–3.42 (4H,
m), 6.86–7.15 (9H, m), 8.34 (1H, d, J = 5.5 Hz); HRMS m/z calcd for
The title compound was prepared in a similar manner described
for 15e. Yield: 25%; pale yellow solid; mp 198–203 °C; IR (KBr)
3428, 3323, 3176, 2974, 1693, 1649, 1584, 1501, 1367, 1241,
C20H24N5OS 382.1702, found 382.1701; Anal. Calcd for C20H23N5OS:
C, 62.97; H, 6.08; N, 18.36. Found: C, 62.79; H, 6.27; N, 18.20.
1169, 1124, 976, 959, 825, 770 cmꢀ1
;
1H NMR (DMSO-d6,
5.1.71. 3-Amino-4-[4-(m-tolyl)-1,4-diazepan-1-yl]thieno[2,3-
b]pyridine-2-carboxamide (15m)
400 MHz) d 1.42 (9H, s), 3.25 (4H, s), 3.29 (4H, s), 6.95 (2H, br s),
7.03 (1H, d, J = 5.4 Hz), 7.12 (2H, br s), 8.45 (1H, d, J = 5.4 Hz); MS
(FAB) m/z: 378 [M+H]+; Anal. Calcd for C17H23N5O3Sꢁ0.3H2O: C,
53.33; H, 6.21; N, 18.29; S, 8.37. Found: C, 53.14; H, 5.86; N,
18.06; S, 8.41.
The title compound was prepared from 12m in a similar man-
ner described for 15l. Yield: 31%; pale yellow solid; mp 209–
212 °C; IR (KBr) 3327, 3169, 2830, 1637, 1579, 1498, 1373, 1234,
1182, 942, 767 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 2.10–2.15
;
(2H, m), 2.22 (3H, s), 3.14–3.18 (2H, m), 3.26–3.28 (2H, m), 3.52
(2H, t, J = 6.3 Hz), 3.73 (2H, t, J = 4.7 Hz), 6.41 (1H, d, J = 7.8 Hz),
6.53–6.56 (2H, m), 6.97 (2H, br s), 7.01 (1H, t, J = 7.8 Hz), 7.05
(1H, d, J = 5.5 Hz), 7.06 (2H, br s), 8.37 (1H, d, J = 5.5 Hz); HRMS
m/z calcd for C20H24N5OS 382.1702, found 382.1699; Anal. Calcd
for C20H23N5OSꢁ0.08H2O: C, 62.73; H, 6.10; N, 18.29; S, 8.37. Found:
C, 62.56; H, 6.08; N, 18.14; S, 8.32.
5.1.67. 3-Amino-4-(4-methylpiperazin-1-yl)thieno[2,3-
b]pyridine-2-carboxamide (15i)
The title compound was prepared in a similar manner described
for 15e. Yield: 22%; pale yellow solid; mp 260–263 °C; IR (KBr)
3502, 3424, 3322, 3161, 2939, 2801, 1653, 1588, 1502, 1451,
1371, 1344, 1288, 1246, 1199, 973, 819, 737, 683, 625, 476 cmꢀ1
;
1H NMR (DMSO-d6, 400 MHz) d 2.26 (3H, s), 2.40–2.72 (4H, br s),
2.85–3.22 (4H, br s), 6.89 (2H, br s), 7.00 (1H, d, J = 5.5 Hz), 7.07
(2H, s), 8.41 (1H, d, J = 5.5 Hz); MS (FAB) m/z: 292 [M+H]+; Anal.
Calcd for C13H17N5OSꢁ0.3H2O: C, 52.61; H, 5.98; N, 23.60; S,
10.80. Found: C, 52.62; H, 5.79; N, 23.63; S, 10.92.
5.1.72. 3-Amino-4-[4-(p-tolyl)-1,4-diazepan-1-yl]thieno[2,3-
b]pyridine-2-carboxamide (15n)
The title compound was prepared from 14n in a similar manner
described for 1. Yield: 89%; pale yellow solid; mp 175–176 °C; IR
(KBr) 3429, 3317, 3170, 3093, 2942, 2833, 1635, 1579, 1520,
5.1.68. 3-Amino-4-(4-phenylpiperazin-1-yl)thieno[2,3-
b]pyridine-2-carboxamide (15j)
1372 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 2.07–2.16 (2H, m),
;
2.18 (3H, s), 3.15–3.22 (2H, m), 3.23–3.30 (2H, m), 3.51 (2H, t,
J = 6.3 Hz), 3.72 (2H, t, J = 4.7 Hz), 6.66 (2H, d, J = 8.2 Hz), 6.92–
6.99 (4H, m), 7.02–7.09 (3H, m), 8.37 (1H, d, J = 5.1 Hz); MS (FAB)
m/z: 382 [M+H]+; Anal. Calcd for C20H23N5OS: C, 62.97; H, 6.08;
N, 18.36; S, 8.41. Found: C, 62.58; H, 6.02; N, 18.23; S, 8.29.
The title compound was prepared in a similar manner described
for 15e. Yield: 35%; pale yellow solid; mp 250–252 °C; IR (KBr)
3438, 3318, 3176, 2832, 1645, 1596, 1579, 1447, 1377, 1343,
1238, 1136, 978, 914, 831, 762, 733, 693, 626, 484 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 2.89–3.71 (8H, br s), 6.70 (1H, t,
J = 7.1 Hz), 6.93 (2H, br s), 6.99 (2H, d, J = 9.0 Hz), 7.07 (1H, d,
J = 5.5 Hz), 7.10 (2H, br s), 7.22 (2H, dd, J = 9.0, 7.1 Hz), 8.44 (1H,
d, J = 5.5 Hz); MS (FAB) m/z: 354 [M+H]+; Anal. Calcd for
5.1.73. 3-Amino-4-[4-(4-fluorophenyl)-1,4-diazepan-1-
yl]thieno[2,3-b]pyridine-2-carboxamide (15o)
The title compound was prepared from 12o in a similar manner
described for 15l. Yield: 47%; pale yellow solid; mp 203–205 °C; IR
C
18H19N5OSꢁ0.26H2O: C, 60.37; H, 5.49; N, 19.56; S, 8.95. Found:
C, 60.18; H, 5.33; N, 19.55; S, 9.02.
(KBr) 3453, 3324, 3179, 2948, 2838, 1646, 1579, 1510, 1369 cmꢀ1
;
1H NMR (DMSO-d6, 500 MHz) d 2.10–2.19 (2H, m), 3.16–3.24 (2H,
m), 3.30 (2H, s), 3.49–3.56 (2H, m), 3.71–3.78 (2H, m), 6.76 (2H, dd,
J = 9.0, 4.4 Hz), 6.96–7.05 (4H, m), 7.06–7.12 (3H, m), 8.40 (1H, d,
J = 5.1 Hz); MS (FAB) m/z: 386 [M+H]+; Anal. Calcd for
5.1.69. 3-Amino-4-(4-phenyl-1,4-diazepan-1-yl)thieno[2,3-
b]pyridine-2-carboxamide (15k)
The title compound was prepared from 14k in a similar manner
described for 1. Yield: 87%; pale yellow solid; mp 215–218 °C; IR
(KBr) 3340, 3316, 3143, 1645, 1598, 1504, 1369, 1233, 939, 752,
C
19H20FN5OSꢁ1.35H2O: C, 57.95; H, 5.81; N, 17.78; F, 4.82; S,
8.14. Found: C, 57.58; H, 5.41; N, 17.76; F, 4.73; S, 7.99.

1640
K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
5.1.74. 3-Amino-4-[4-(4-tert-butylphenyl)-1,4-diazepan-1-
yl]thieno[2,3-b]pyridine-2-carboxamide (15p)
Anal. Calcd for C22H25N5O3Sꢁ1.1H2O: C, 57.53; H, 5.97; N, 15.25;
S, 6.98. Found: C, 57.65; H, 5.91; N, 15.04; S, 6.97.
The title compound was prepared from 14p in a similar manner
described for 1. Yield: 72%; pale yellow solid; mp 231–232 °C; IR
5.1.79. 3-Amino-4-(4-{4-[(dimethylamino)carbonyl]phenyl}-
1,4-diazepan-1-yl)thieno[2,3-b]pyridine-2-carboxamide (15u)
The title compound was prepared from 14u in a similar manner
described for 1. Yield: 83%; pale brown solid; mp 159–161 °C; IR
(KBr) 3440, 3324, 3182, 2957, 1645, 1579, 1519, 1364 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 1.21 (9H, s), 2.06–2.17 (2H, m),
3.16–3.22 (2H, m), 3.23–3.30 (2H, m), 3.52 (2H, t, J = 6.3), 3.74
(2H, t, J = 4.7), 6.69 (2H, d, J = 9.0), 6.89 (2H, br s), 7.03–7.09 (3H,
m), 7.17 (2H, d, J = 9.0 Hz), 8.38 (1H, d, J = 5.5 Hz); MS (EI) m/z:
423 [M+]; Anal. Calcd for C23H29NsOSꢁ0.27H2O: C, 64.48; H, 6.95;
N, 16.35; S, 7.48. Found: C, 64.17; H, 6.64; N, 16.31; S, 7.43.
(KBr) 3437, 3327, 3187, 2930, 2847, 1606, 1497, 1387 cmꢀ1 1H
;
NMR (DMSO-d6, 400 MHz) d 2.11–2.20 (2H, m), 2.97 (6H, s),
3.16–3.24 (2H, m), 3.27–3.30 (2H, m), 3.58 (2H, t, J = 6.3 Hz),
3.78–3.84 (2H, m), 6.76 (2H, d, J = 9.0 Hz), 6.97 (2H, br s), 7.04–
7.12 (3H, m), 7.28 (2H, d, J = 9.0 Hz), 8.38 (1H, d, J = 5.1 Hz); MS
(FAB) m/z: 439 [M+H]+; Anal. Calcd for C22H26N6O2Sꢁ1.2H2O: C,
57.42; H, 6.22; N, 18.26; S, 6.97. Found: C, 57.17; H, 6.03; N,
18.45; S, 6.83.
5.1.75. 3-Amino-4-[4-(4-methoxyphenyl)-1,4-diazepan-1-
yl]thieno[2,3-b]pyridine-2-carboxamide (15q)
The title compound was prepared from 12q in a similar manner
described for 15l. Yield: 67%; pale yellow solid; mp 206–208 °C; IR
(KBr) 3446, 3328, 3168, 1578, 1511, 1370, 1240, 1037, 937,
5.1.80. 3-Amino-4-[4-[4-(methylcarbamoyl)phenyl]-1,4-
diazepan-1-yl]thieno[2,3-b]pyridine-2-carboxamide (15v)
The title compound was prepared from 14v in a similar manner
described for 1. Yield: 46%; pale yellow solid; mp 132–134 °C; IR
816 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 1.78–1.86 (2H, m),
;
2.89–2.95 (2H, m), 2.97–3.01 (2H, m), 3.19 (2H, t, J = 5.9 Hz), 3.37
(3H, s), 3.37–3.42 (2H, m), 6.43 (2H, d, J = 9.4 Hz), 6.51 (2H, d,
J = 9.4 Hz), 6.69 (2H, br s), 6.77–6.79 (3H, m), 8.10 (1H, d,
J = 5.5 Hz); HRMS m/z calcd for C20H24N5O2S 398.1651, found
398.1635; Anal. Calcd for C20H23N5O2Sꢁ0.52H2O: C, 59.04; H,
5.96; N, 17.21. Found: C, 58.73; H, 6.09; N, 17.52.
(KBr) 3440, 3324, 1642, 1605, 1508, 1368, 1203 cmꢀ1 1H NMR
;
(DMSO-d6, 500 MHz) d 2.13–2.20 (2H, m), 2.74 (3H, d, J = 4.4 Hz),
3.15–3.23 (2H, m), 3.27–3.35 (2H, m), 3.61 (2H, t, J = 6.4 Hz),
3.80–3.86 (2H, m), 6.79 (2H, d, J = 8.8 Hz), 7.01 (2H, br s), 7.07
(1H, d, J = 5.4 Hz), 7.10 (2H, br s), 7.70 (2H, d, J = 8.8 Hz), 8.06
(1H, q, J = 4.4 Hz), 8.40 (1H, d, J = 5.4 Hz); MS (FAB) m/z: 425
[M+H]+; Anal. Calcd for C21H24N6O2Sꢁ2.19H2O: C, 54.36; H, 6.17;
N, 18.11; S, 6.91. Found: C, 54.54; H, 5.99; N, 18.04; S, 6.65.
5.1.76. 3-Amino-4-[4-(4-isopropoxyphenyl)-1,4-diazepan-1-
yl]thieno[2,3-b]pyridine-2-carboxamide (15r)
The title compound was prepared from 14r in a similar manner
described for 1. Yield: 79%; pale yellow solid; mp 173–175 °C; IR
(KBr) 3441, 3324, 2973, 1644, 1579, 1510, 1370, 1235 cmꢀ1 1H
;
5.1.81. 3-Amino-4-(4-{4-[2-(dimethylamino)-2-
oxoethyl]phenyl}-1,4-diazepan-1-yl)thieno[2,3-b]pyridine-2-
carboxamide (15w)
NMR (DMSO-d6, 400 MHz) d 1.21 (6H, d, J = 5.9 Hz), 2.07–2.16
(2H, m), 3.16–3.24 (2H, m), 3.25–3.33 (2H, m), 3.47 (2H, t,
J = 5.9 Hz), 3.69 (2H, t, J = 4.7 Hz), 4.34–4.40 (1H, m), 6.68 (2H, d,
J = 9.0 Hz), 6.76 (2H, d, J = 9.0 Hz), 6.97 (2H, br s), 7.03–7.11 (3H,
m), 8.37 (1H, d, J = 5.5 Hz); MS (EI) m/z: 425 [M+]; Anal. Calcd for
The title compound was prepared from 14w in a similar manner
described for 1. Yield: 56%; pale yellow solid; mp 133–135 °C; IR
(KBr) 3435, 3326, 3189, 2935, 2839, 1634, 1579, 1519 cmꢀ1 1H
;
C22H27N5O2S: C, 62.09; H, 6.40; N, 16.46; S, 7.54. Found: C,
NMR (DMSO-d6, 500 MHz) d 2.10–2.18 (2H, m), 2.82 (3H, s), 2.98
(3H, s), 3.15–3.23 (2H, m), 3.25–3.33 (2H, m), 3.49–3.56 (4H, m),
3.72–3.78 (2H, m), 6.71 (2H, d, J = 8.8 Hz), 7.00 (2H, br s), 7.03
(2H, d, J = 8.8 Hz), 7.07 (1H, d, J = 5.4 Hz), 7.09 (2H, br s), 8.39
(1H, d, J = 5.4 Hz); MS (FAB) m/z: 453 [M+H]+; Anal. Calcd for
61.83; H, 6.23; N, 16.32; S, 7.38.
5.1.77. 3-Amino-4-[4-(4-cyanophenyl)-1,4-diazepan-1-
yl]thieno[2,3-b]pyridine-2-carboxamide (15s)
The title compound was prepared from 12s in a similar manner
described for 15l. Yield: 33%; pale yellow solid; mp 151–153 °C; IR
(KBr) 3439, 3327, 2211, 1605, 1519, 1366, 1178, 938, 818,
C23H28N6O2Sꢁ1.16H2O: C, 58.35; H, 6.45; N, 17.75. Found: C,
58.10; H, 6.19; N, 18.03.
544 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 2.13–2.18 (2H, m),
;
3.17–3.19 (2H, m), 3.22–3.30 (2H, m), 3.61 (2H, t, J = 6.3 Hz), 3.84
(2H, t, J = 5.1 Hz), 6.86 (2H, d, J = 9.0 Hz), 6.96 (2H, br s), 7.05 (1H,
d, J = 5.5 Hz), 7.07 (2H, br s), 7.52 (2H, t, J = 9.0 Hz), 8.37 (1H, d,
J = 5.5 Hz); HRMS m/z calcd for C20H21N6OS 393.1497, found
393.1501; Anal. Calcd for C20H20N6OSꢁ0.94H2O: C, 58.67; H, 5.39;
N, 20.53. Found: C, 58.99; H, 5.51; N, 20.22.
5.1.82. 3-Amino-4-[4-(2-pyridyl)-1,4-diazepan-1-yl]thieno[2,3-
b]pyridine-2-carboxamide (15x)
The title compound was prepared from 12x in a similar manner
described for 15l. Yield: 27%; pale yellow solid; mp 237–239 °C; IR
(KBr) 3444, 3325, 3167, 1650, 1596, 1496, 1371, 942, 770 cmꢀ1; 1H
NMR (DMSO-d6, 400 MHz) d 2.11–2.17 (2H, m), 3.17–3.32 (4H, m),
3.70 (2H, t, J = 6.3 Hz), 3.96–4.03 (2H, m), 6.57 (1H, dd, J = 7.0,
5.1 Hz), 6.69 (1H, d, J = 8.6 Hz), 7.01 (2H, br s), 7.07 (1H, d,
J = 5.1 Hz), 7.10 (2H, br s), 7.51 (1H, ddd, J = 8.6, 7.0, 2.0 Hz), 8.09
(1H, dd, J = 5.1, 2.0 Hz), 8.39 (1H, d, J = 5.1 Hz); HRMS m/z calcd
5.1.78. Ethyl 4-[4-(3-amino-2-carbamoyl-thieno[2,3-b]pyridin-
4-yl)-1,4-diazepan-1-yl]benzoate (15t)
To a DMF (1.3 mL) solution of 14t (0.250 g, 0.654 mmol) were
added 2-chloroacetamide (73.0 mg, 0.781 mmol) and 20% EtOH
solution of NaOEt (0.760 mL, 1.94 mmol), and the mixture was stir-
red at room temperature for 30 min. 1 M Hydrochloric acid was
added to the mixture, and the deposited solid was filtered and
washed with water and EtOH to give the title compound
(0.207 g, 72%) as pale yellow solid. Mp 124–126 °C; IR (KBr)
for
C18H21N6OS 369.1498, found 369.1497; Anal. Calcd for
C
18H20N6SOꢁ0.3H2O: C, 57.83; H, 5.55; N, 22.48; S, 8.58. Found: C,
57.99; H, 5.35; N, 22.43; S, 8.59.
5.1.83. 3-Amino-4-[4-(4-pyridyl)-1,4-diazepan-1-yl]thieno[2,3-
b]pyridine-2-carboxamide (15y)
3440, 3324, 1695, 1646, 1603, 1365, 1280, 1186 cmꢀ1 1H NMR
;
The title compound was prepared from 12y in a similar manner
described for 15l. Yield: 12%; pale yellow solid; mp 288–291 °C
(decomposition); IR (KBr) 3334, 1650, 1597, 1573, 1510,
(DMSO-d6, 500 MHz) d 1.28 (3H, t, J = 7.0 Hz), 2.13–2.22 (2H, m),
3.14–3.24 (2H, m), 3.27–3.36 (2H, m), 3.64 (2H, t, J = 6.4 Hz),
3.82–3.89 (2H, m), 4.23 (2H, q, J = 7.0 Hz), 6.84 (2H, d, J = 9.3 Hz),
6.99 (2H, br s), 7.08 (1H, d, J = 5.4 Hz), 7.10 (2H, br s), 7.77 (2H,
d, J = 9.3 Hz), 8.40 (1H, d, J = 5.4 Hz); MS (FAB) m/z: 440 [M+H]+;
1367 cmꢀ1 1H NMR (DMSO-d6, 400 MHz) d 2.13–2.18 (2H, m),
;
3.15–3.30 (4H, m), 3.56–3.59 (2H, m), 3.79–3.81 (2H, m), 6.68

K. Saito et al. / Bioorg. Med. Chem. 21 (2013) 1628–1642
1641
(2H, d, J = 6.7 Hz), 6.98 (2H, br s), 7.06 (1H, d, J = 5.1 Hz), 7.09 (2H,
5.2. Biology
br s), 8.09 (2H, d, J = 6.7 Hz), 8.38 (1H, d, J = 5.1 Hz); HRMS m/z
calcd for C18H21N6OS 369.1498, found 369.1497; Anal. Calcd for
5.2.1. ALP assay
C
18H20N6OSꢁ0.3H2O: C, 57.83; H, 5.55; N, 22.48; S, 8.58. Found: C,
ST2 cells were seeded at 4000 cells/well in a 96 well plate (Fal-
con #3072) and incubated at 37 °C with or without test compound
for 4 days. After the incubation period, the plate was washed by
PBS twice. The ALP activity was assayed by the method of Lowry
et al.8
57.76; H, 5.48; N, 22.46; S, 8.50.
5.1.84. 3-Amino-4-(4-thiazol-2-yl-1,4-diazepan-1-yl)thieno[2,3-
b]pyridine-2-carboxamide (15z)
The title compound was prepared from 12z in a similar manner
described for 15l. Yield: 31%; pale yellow solid; mp 243–245 °C; IR
(KBr) 3432, 3310, 3154, 1648, 1580, 1509, 1375, 933, 614 cmꢀ1; 1H
NMR (DMSO-d6, 400 MHz) d 2.48–2.50 (2H, m), 3.19–3.37 (4H, m),
3.62 (2H, t, J = 5 9 Hz), 3.93–3.95 (2H, m), 6.73 (1H, d, J = 3.5 Hz),
7.00 (2H, br s), 7.06 (1H, d, J = 5.5 Hz), 7.10 (2H, br s), 7.13 (1H,
d, J = 3.5 Hz), 8.39 (1H, d, J = 5.5 Hz); HRMS m/z calcd for
5.2.2. Calcification assay
Bone marrow cells were prepared and cultured according to the
method of Maniatopoulos et al.10 Briefly, rat bone marrow cells
were isolated from the femora of Wistar rats and cultured in a tis-
sue culture flask. After 7 days, the cells were harvested, plated in
dishes, and cultured with or without test compound for 10 days.
C16H19N6OS2 375.1062, found 375.1064; Anal. Calcd for
C16H18N6OS2ꢁ1.1H2O: C, 48.74; H, 5.16; N, 21.31; S, 16.26. Found:
5.2.3. OVX rat study
C, 48.98; H, 5.03; N, 21.22; S, 15.89.
All experimental procedures were performed in accordance
with the in-house guideline of the Institutional Animal Care and
Use Committee of Daiichi Sankyo Co., Ltd. Eight-week-old F344
rats (Charles River) were either sham-operated or ovariectomized
(OVX). OVX rats were orally administered with the test compound
for 6 weeks. Sham-operated rats were also treated with vehicle
(0.5% methylcellulose solution). Areal Bone mineral density
(aBMD) of femurs and tibiae was measured by dual energy X-ray
absorptiometry (DXA; DCS-600R, Aloka Co. Ltd., Tokyo, Japan). Ser-
um osteocalcin was analyzed by the commercial ELISA kit (Biotrak,
RPNJ404).
5.1.85. 3-Amino-4-piperazin-1-ylthieno[2,3-b]pyridine-2-
carboxamide dihydrochloride (15aa)
Compound 15h (340 mg, 0.901 mmol) was suspended in 1,4-
dioxane (10 mL) and was added 4 M hydrogen chloride in 1,4-diox-
ane (4.0 mL), and the mixture was stirred at room temperature for
2 h. The solvent was removed in vacuo to give the title compound
(316 mg, 100%) as yellow solid. Mp 270–280 °C; IR (KBr) 3320,
3180, 2925, 2770, 2717, 1648, 1604, 1446, 1395, 1259, 1059,
973, 906, 797, 556, 540, 516 cmꢀ1 1H NMR (DMSO-d6, 400 MHz)
;
d 3.58–4.28 (8H, br s), 7.13 (1H, d, J = 5.1 Hz), 7.24 (2H, br s),
8.53 (1H, d, J = 5.1 Hz), 9.45 (2H, br s); MS (FAB) m/z: 278
[M+H]+; Anal. Calcd for C12H15N5OSꢁ2HClꢁH2O: C, 39.14; H, 5.20;
N, 19.02. Found: C, 38.99; H, 5.13; N, 18.77.
Acknowledgment
We would like to thank Dr. Kazumasa Aoki for his encourage-
ment and helpful support.
5.1.86. 4-[4-(3-Amino-2-carbamoyl-thieno[2,3-b]pyridin-4-yl)-
1,4-diazepan-1-yl]benzoic acid (15ab)
Supplementary data
Compound 15t (130 mg, 0.296 mmol) was suspended in ethanol
(6.0 mL) and 1 M aqueous solution of NaOH (3.0 mL) was added,
and the mixture was stirred under reflux for 10 h. After cooling
to room temperature, 1 M hydrochloric acid (3.0 mL) was added
to the mixture, and the deposited solid was filtered and washed
with water and ethanol to give the title compound (96.0 mg,
79%) as pale yellow solid. IR (KBr) 3444, 3327, 3181, 2494, 1645,
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmc.2013.01.071.
These data include MOL files and InChiKeys of the most important
compounds described in this article.
References and notes
1600, 1368, 1270, 1184, 939, 772 cmꢀ1
;
1H NMR (DMSO-d6,
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400 MHz) d 2.07–2.12 (2H, m), 3.15–3.22 (2H, m), 3.26–3.36 (2H,
m), 3.62 (2H, t, J = 6.4 Hz), 3.76–3.88 (2H, m), 6.79 (2H, d,
J = 9.0 Hz), 6.97 (2H, br s), 7.06 (1H, d, J = 5.4 Hz), 7.08 (2H, br s),
7.73 (2H, d, J = 9.0 Hz), 8.38 (1H, d, J = 5.4 Hz); MS (FAB) m/z: 412
[M+H]+.
5.1.87. 3-Amino-4-[4-(4-carbamoylphenyl)-1,4-diazepan-1-
yl]thieno[2,3-b]pyridine-2-carboxamide (15ac)
To a DMSO (2.0 mL) solution of 15s (52.0 mg, 0.133 mmol) were
added K2CO3 (13.0 mg, 0.0941 mmol) and dropwise 30% H2O2
(0.400 mL, 3.92 mmol), and the reaction mixture was stirred at
room temperature for 1 h. Water was added to the mixture, and
the deposited solid was filtered and washed with water and etha-
nol to give the title compound (38.7 mg, 71%) as pale yellow solid.
Mp 165–167 °C; IR (KBr) 3442, 3325, 3188, 1645, 1601, 1367 cmꢀ1
;
1H NMR (DMSO-d6, 400 MHz) d 2.11–2.22 (2H, m), 3.13–3.24 (2H,
m), 3.26–3.35 (2H, m), 3.56–3.65 (2H, m), 3.79–3.87 (2H, m), 6.78
(2H, d, J = 9.0 Hz), 6.91 (1H, br s), 7.01 (2H, br s), 7.08 (1H, d,
J = 5.5 Hz), 7.10 (2H, br s), 7.63 (1H, br s), 7.74 (2H, t, J = 9.0 Hz),
8.40 (1H, d, J = 5.5 Hz); MS (EI) m/z: 411 [M+H]+; Anal. Calcd for
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