Discovery of Ipragliflozin (ASP1941): A novel C-glucoside with benzothiophene structure as a potent and selective sodium glucose co-transporter 2 (SGLT2) inhibitor for the treatment of type 2 diabetes mellitus

Article abstract of DOI:10.1016/j.bmc.2012.03.051

A series of C-glucosides with various heteroaromatics has been synthesized and its inhibitory activity toward SGLTs was evaluated. Upon screening several compounds, the benzothiophene derivative (14a) was found to have potent inhibitory activity against SGLT2 and good selectivity versus SGLT1. Through further optimization of 14a, a novel benzothiophene derivative (14h; ipragliflozin, ASP1941) was discovered as a highly potent and selective SGLT2 inhibitor that reduced blood glucose levels in a dose-dependent manner in diabetic models KK-A^y mice and STZ rats.

Full text of DOI:10.1016/j.bmc.2012.03.051

Bioorganic & Medicinal Chemistry 20 (2012) 3263–3279
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Bioorganic & Medicinal Chemistry
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Discovery of ipragliflozin (ASP1941): A novel C-glucoside with
benzothiophene structure as a potent and selective sodium glucose
co-transporter 2 (SGLT2) inhibitor for the treatment of type 2 diabetes mellitus
Masakazu Imamura a, , Keita Nakanishi a, Takayuki Suzuki a, Kazuhiro Ikegai a, Ryota Shiraki a,
⇑
Takashi Ogiyama a, Takeshi Murakami a, Eiji Kurosaki a, Atsushi Noda b, Yoshinori Kobayashi b,
Masayuki Yokota b, Tomokazu Koide b, Kazuhiro Kosakai b, Yasufumi Ohkura b, Makoto Takeuchi a,
Hiroshi Tomiyama b, Mitsuaki Ohta a
a Drug Discovery Research, Astellas Pharma Inc., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan
b Research Laboratories, Kotobuki Pharmaceutical Co., Ltd, 6351 Sakaki-machi, Hanishina-gun, Nagano 389-0697, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of C-glucosides with various heteroaromatics has been synthesized and its inhibitory activity
toward SGLTs was evaluated. Upon screening several compounds, the benzothiophene derivative (14a)
was found to have potent inhibitory activity against SGLT2 and good selectivity versus SGLT1. Through
further optimization of 14a, a novel benzothiophene derivative (14h; ipragliflozin, ASP1941) was
discovered as a highly potent and selective SGLT2 inhibitor that reduced blood glucose levels in a
dose-dependent manner in diabetic models KK-Ay mice and STZ rats.
Received 16 February 2012
Revised 21 March 2012
Accepted 22 March 2012
Available online 29 March 2012
Keywords:
Diabetes
Ó 2012 Elsevier Ltd. All rights reserved.
SGLT2 inhibitor
Benzothiophene
Ipragliflozin
1. Introduction
because they have a distinct mechanism of action that reduces
blood glucose levels independently of insulin secretion.7
Type 2 diabetes mellitus (T2DM) is a metabolic disorder mark-
edly increasing in Westernized societies and developing countries
characterized by fasting and postprandial hyperglycemia due to
the impaired insulin secretion and/or insulin resistance.1–3 Un-
treated hyperglycemics are at risk of micro- and macrovascular
complications including retinopathy, nephropathy, stroke, ampu-
tation and myocardial infarction.4 Therefore, therapeutic strategies
for T2DM are currently focused on controlling blood glucose
levels.
To date, several oral drugs that enhance insulin secretion and/or
improve insulin sensitivity have been developed. However, due to
their limited efficacy and adverse side effects, it is difficult to main-
tain good glycemic control in most T2DM patients. Recent studies
suggest that only about one-third of patients treated for T2DM
Plasma glucose is filtered in the glomerulus and then reab-
sorbed in the proximal tubules of the kidney. Renal glucose
reabsorption is mediated by two SGLTs: SGLT1, a low-capacity,
high-affinity transporter,8,9 and SGLT2,
a high-capacity, low-
affinity transporter.10,11 While SGLT2 is mainly expressed in the
S1 and S2 segments of the proximal tubules, SGLT1 is distributed
mainly in the small intestine and also present in the S3 segment
of the proximal tuble.11 Humans with SGLT1 gene mutations expe-
rience glucose–galactose malabsorption, resulting in frequent,
watery diarrhea and dehydration when on a glucose diet, indicat-
ing that SGLT1 is the major glucose transporter in the small intes-
tine.12,13 In contrast, persistent renal glucosuria is the only
reported phenotype of humans with SGLT2 gene mutations.14,15
This observation suggests that SGLT2 is responsible for the major-
ity of renal glucose reabsorption and that selective SGLT2 inhibi-
tors are desired to avoid the gastrointestinal side effects related
to SGLT1 inhibition.
achieve the glycemic target: a glycosylated hemoglobin (HbA1c
)
of <7%.5,6 For that reason, more effective agents are needed for
the successful management of T2DM. Among these, inhibitors of
sodium glucose co-transporters (SGLTs) are an attractive option,
Selective SGLT2 inhibitors have recently been shown to enhance
urinary glucose excretion and reduce hyperglycemia in patients
with T2DM.16,17 SGLT2 inhibitors could increase the caloric output
in urine due to the urinary glucose excretion, suggesting that
SGLT2 inhibitors do not result in the weight gain often seen with
⇑
Corresponding author. Tel.: +81 29 829 6653.
E-mail address: masakazu.imamura@astellas.com (M. Imamura).
0968-0896/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmc.2012.03.051

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M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
other antihyperglycemic agents currently prescribed, making them
an even more expected candidate for next-generation of anti-
diabetic agents.
Phlorizin (1) is a natural O-glucoside that is a well known po-
tent nonselective SGLT inhibitor.18 However, 1 is not considered
a suitable drug candidate not only because of its inhibitory activity
toward SGLT1 but also because of its poor metabolic stability due
to susceptible b-glucosidase-mediated degradation.
(iPrMgBr) to benzylbromide. Substitution of glucosyl fluoride 2731
with a Grignard reagent prepared from 26 and iPrMgBr gave com-
pound 28. Removal of the benzyl groups in 28 by hydrogenation
yielded pyrrol-3-yl C-glucoside derivative 9.
Scheme 3 shows the synthesis of pyridyl C-glucoside derivative
10. Lithium halogen exchange of 2,6-dibromopyridine 29 followed
by the addition of a lithiated aromatic to gluconolactone 23 yielded
lactol, which was then reduced by treatment with Et3SiH and tri-
fluoroacetic acid (TFA) to give pyridyl C-glucoside 30. Hydroxy-
carbonylation was carried out on 30 under atmosphere of CO to
give picolinic acid derivative 31. Compound 31 was converted to
Weinreb amide 32, which was reduced to an aldehyde. A Grignard
reagent prepared from 4-ethyliodobenzene and iPrMgBr was
added to the aldehyde to give compound 33. Barton reduction of
the generated alcohol yielded compound 34. Removal of the benzyl
groups from 34 by BCl3 afforded pyridyl C-glucoside derivative 10.
Synthesis of pyrazin-2-yl C-glucoside derivative 11 is depicted
in Scheme 4. 2,6-dichloropyrazine was lithiated by lithium diiso-
propyl amide (LDA) and then a lithiated aromatic was added to
gluconolactone 23 to give lactol. Reduction of lactol by treatment
with Et3SiH and TFA gave pyrazin-2-yl C-glucoside 36. Lithiation
of 36 with lithium tetramethylpiperidide (LiTMP) followed by the
addition of a lithiated aromatic to 4-ethylbenzaldehyde and reduc-
tion of the nascent alcohol with Et3SiH and TFA yielded compound
37. Dechlorination of 37 by hydrogenation followed by removal of
the benzyl groups by treatment with BCl3 generated pyrazin-2-yl
C-glucoside derivative 11.
In a series of previous reports,19–25 researchers at Mitsubishi
Tanabe Pharma Co. disclosed the structure–activity relationships
(SARs) of 1 and the discovery of another selective, potent SGLT2
inhibitor, T-1095A (2). However, to achieve glucose lowering in
diabetic mice, oral administration of the methyl carbonate pro-
drug of 2, T-1095 (3), was needed due to the b-glucosidase-medi-
ated metabolic instability of the O-glucoside linkage in T-1095A.
On the other hand, C-glucoside derivatives, such as compounds
426 and 527,28 were found to be potent SGLT2 inhibitors that are
metabolically more stable than O-glucosides.
Here, we describe the C-glucoside derivatives containing het-
eroaromatics as SGLT2 inhibitors (compounds 6 and 7 in Fig. 1).
A number of compounds with various heteroaromatics were syn-
thesized and evaluated, including SAR studies, which culminated
in the discovery of a novel benzothiophene derivative, 14h (Ipragli-
flozin, ASP1941), a potent and selective SGLT2 inhibitor29 that
exhibits properties warranting a clinical development for the
treatment of T2DM mellitus.
Preparation of key intermediate 43 is shown in Scheme 5. 3-
Bromobenzylalcohol (39) was protected with a tert-butyldiphenyl-
silyl (TBDPS) group to give compound 40. Lithium halogen ex-
change of 40 followed by the addition of a lithiated aromatic to
gluconolactone 23 yielded lactol, which was reduced by treatment
with Etr3SiH and BF3ÁOEt2 to give phenyl C-glucoside 41. Removal
of the TBDPS group by tetrabutylammoniumfluoride (TBAF) fol-
lowed by the oxidation of benzylalcohol to benzaldehyde with
manganese (IV) oxide (MnO2) afforded the key intermediate 43.
Compounds 12 and 19 were synthesized as shown in Scheme 6.
2-Bromopyridine (44) and N-methylbenzimidazole (45) were lith-
iated and added to 43 to give alcohols 46 and 47. Barton reduction
of these alcohols yielded compounds 48 and 49, while subsequent
removal of the benzyl groups by BCl3 afforded pyridine derivative
12 and N-methylbenzimidazole derivative 19.
2. Chemistry
Preparation of thiophen-3-yl C-glucoside derivative 8 is out-
lined in Scheme 1. Addition of a Grignard reagent to aldehyde 20
followed by reduction of the resulting alcohol 21 with triethylsi-
lane (Et3SiH) and boron trifluoride ethyl ether complex (BF3ÁOEt2)
gave 22. Lithium halogen exchange of 22 followed by the addition
of a lithiated aromatic to gluconolactone 2330 yielded lactol, which
was reduced by treatment with Et3SiH and BF3ÁOEt2 to give com-
pound 24. Removal of the benzyl groups from 24 with boron tri-
chloride (BCl3) generated thiophen-3-yl C-glucoside derivative 8.
Pyrrol-3-yl C-glucoside derivative 9 was synthesized as shown
in Scheme 2. Aglycon 26 was prepared by adding a Grignard re-
agent generated by pyrrole 25 and isopropyl magnesium bromide
Scheme 7 shows the synthesis of benzothiophene derivative
14a and benzofuran derivative 15. The lithiation of benzothio-
phene (50) and benzofuran (51) followed by the addition of a lith-
iated aromatic to 43 yielded lactols, which were reduced by
treatment with Et3SiH and BF3ÁOEt2 to give compounds 52 and
53. The benzyl groups of these compounds were removed by treat-
ment with BCl3 to give compounds 14a and 15.
HO
O
OH
O
OH
OH
O
O
O
O
O
HO
HO
RO
HO
OH
OH
OH
OH
2 : R = H; T-1095A
1 : Phlorizin
Synthesis of C-glucosylated benzylbromide 56 is depicted in
Scheme 8. Conversion of the benzyl groups in 41 to acetyl groups
followed by removal of the TBDPS group yielded benzylalcohol
55. Bromination of 55 with carbon tetrabromide and triphenyl-
phosphine gave the desired intermediate 56.
Preparation of N-methylindole derivative 16 is outlined in
Scheme 9. Conversion of N-methylindole 57 to organo stannyl re-
agent, followed by Stille coupling of this organo stannyl reagent
to 56 using a palladium catalyst yielded compound 58. Removal
of the acetyl groups from 58 in a basic condition generated 16.
Conversion of compound 56 to an organo zinc reagent followed
by Negishi coupling with 2-methylthiopyrazine, 2-chlorobenzothi-
azole and 2-chlorobenzoxazole using a palladium catalyst gave
compounds 59, 60 and 61, respectively. The acetyl groups of these
compounds were removed in a basic condition to give pyrazine
derivative 13, benzothiazole derivative 17 and benzoxazole
derivative 18 (Scheme 10).
3 : R = CO2Me; T-1095
OH
O
O
O
O
HO
HO
HO
HO
OH
OH
OH
OH
4
5
R2
R2
R1
R1
Het
Het
O
O
RO
HO
RO
HO
OH
OH
OH
OH
6
7
Het : Heteroaryl
Figure 1. Structure of SGLT2 inhibitors.

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3265
O
b
S
a
c
d
S
CHO
O
S
Br
Br
Br
O
O
OH
21
20
BnO
22
BnO
OBn
OBn
O
O
23
S
S
e
O
O
BnO
BnO
HO
HO
OBn
OH
OBn
OH
8
24
Scheme 1. Reagents and conditions: (a) 4-methoxyphenylmagnesiumbromide, THF, 0 °C, 96%; (b) Et3SiH, BF3ÁOEt2, CH2Cl2, À20 °C, 70%; (c) n-BuLi (1.6 M in hexane), THF,
À78 °C then 23, 71%; (d) Et3SiH, BF3ÁOEt2, CH2Cl2, À78 °C to À20 °C, quant.; (e) BCl3 (1.0 M in heptane), pentamethylbenzene, CH2Cl2, À78 °C, 46%.
H
N
a
b
H
N
H
N
O
BnO
BnO
OBn
O
F
OBn
BnO
BnO
28
26
25
OBn
OBn
27
H
N
c
O
HO
HO
OH
OH
9
Scheme 2. Reagents and conditions: (a) iPrMgBr, then 4-ethylbenzylbromide, benzene, 60 °C, 19%; (b) iPrMgBr, THF, rt then 27, 38%; (c) Pd(OH)2, H2, EtOAc–MeOH, rt, 13%.
a, b
c, d
e
O
O
BnO
BnO
N
Br
BnO
BnO
N
COOH
Br
N
Br
OBn
OBn
OBn
OBn
30
29
31
f, g
h, i
O
N
O
BnO
N
OBn
O
BnO
BnO
N
O
OH
BnO
OBn
OBn
OBn
32
33
j
O
O
BnO
BnO
N
HO
HO
N
OBn
OH
OBn
OH
34
10
Scheme 3. Reagents and conditions: (a) n-BuLi (1.6 M in hexane), THF, À78 °C then 23, 67%; (b) Et3SiH, TFA, CH2Cl2, rt, 70%; (c) Pd(OAc)2, dppp, CO, Et3N, DMSO-MeOH, 70 °C,
76%; (d) 1 M NaOH aq, THF–MeOH, rt, quant.; (e) N,O-dimethylhydroxylamine hydrochloride, WSC-HCl, HOBt, Et3N, DMF, rt, 84%; (f) DIBAL-H, CH2Cl2, 0 °C, 62%; (g) 4-
Ethyliodobenzene, iPrMgCl, THF, À30 °C, 90%; (h) NaH, CS2, MeI, THF, rt; (i) n-Bu3SnH, AIBN, toluene, reflux, 70% (2 steps); (j) BCl3 (1.0 M in heptane), pentamethylbenzene,
CH2Cl2, À78 °C, 81%.
Schemes 11 and 12 show the synthesis of benzothiophene deriv-
atives having several substitution groups on the central benzene
ring. Lithiation of 50 followed by the addition of a lithiated aromatic
to compounds 64 or 65, which were prepared from the hydroxyben-
zaldehydes 62 or 63, respectively, yielded alcohols those were re-
duced with Et3SiH and BF3ÁOEt2 to give aglycons 66 and 67.
Lithium halogen exchange of 66 and 67 followed by the addition
of a lithiated aromatic to gluconolactone 23 yielded lactols those
were reduced by treatment with Et3SiH and BF3ÁOEt2 to give com-
pounds 68 and 69. Successive removal of the methoxymethyl group
and benzyl groups generated compounds 14b and 14f, both having a
hydroxy group on the central benzene ring, although at different
position (Scheme 11). Methylation of intermediates 70 and 71
followed by removal of the benzyl groups gave methoxy derivatives
14c and 14g (Scheme 11). Compounds with fluorine or chlorine on
the central benzene ring (compounds 14d, 14e, 14h and 14i) were
synthesized using a procedure similar to Scheme 11 (Scheme 12).
Aglycons 74, 75, 76 and 77 were prepared by adding lithiated ben-
zothiophene to the corresponding benzaldehydes and reducing the
alcohol. The addition of lithiated aglycons generated by lithium

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M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
Cl
N
Cl
Cl
N
Cl
a, b
c, d
Cl
N
Cl
e
O
O
BnO
BnO
N
BnO
BnO
N
N
OBn
OBn
OBn
OBn
35
37
36
N
N
N
N
f
O
O
BnO
HO
HO
BnO
OBn
OH
OBn
OH
38
11
Scheme 4. Reagents and conditions: (a) LDA, THF, À78 °C then 23, 66%; (b) Et3SiH, TFA, CH2Cl2, rt, 28%; (c) LiTMP, THF, À78 °C then 4-ethylbenzaldehyde, 34%; (d) Et3SiH,
TFA, CH2Cl2, rt, 63%; (e) 10% Pd/C, H2, MeOH–THF, rt, 50%; (f) BCl3 (1.0 M in heptane), pentamethylbenzene, CH2Cl2, À78 °C, 43%.
a
b, c
d
O
OTBDPS
BnO
BnO
OTBDPS
OH
Br
Br
OBn
OBn
40
39
41
e
O
OH
O
BnO
BnO
BnO
BnO
CHO
OBn
OBn
OBn
OBn
42
43
Scheme 5. Reagents and conditions: (a) TBDPSCl, imidazole, DMF, rt, quant.; (b) n-BuLi (1.6 M in hexane), THF, À78 °C then 23; (c) Et3SiH, BF3ÁOEt2, CH2Cl2, À20 °C, 29% (2
steps); (d) TBAF (1.0 M in THF), THF, rt, 46%; (e) MnO2, CH2Cl2, rt, 92%.
Ar
Ar
a
b, c
O
O
BnO
BnO
BnO
BnO
Ar-X
OH
N
OBn
OBn
OBn
OBn
46 : Ar =
47 : Ar =
48 : Ar =
49 : Ar =
44 : Ar =
X = Br
N
N
N
*
*
*
*
*
N
N
X = H
45 : Ar =
*
N
N
N
Ar
d
O
HO
HO
OH
OH
12 : Ar =
19 : Ar =
N
N
*
*
N
Scheme 6. Reagents and conditions: (a) n-BuLi (1.6 M in hexane), THF, À78 °C then 43, 63% (46), 35% (47); (b) NaH, CS2, MeI, THF, rt; (c) n-Bu3SnH, AIBN, toluene, reflux, 87%
(2 steps) (48), 82% (2 steps) (49); (d) BCl3 (1.0 M in heptane), pentamethylbenzene, CH2Cl2, À78 °C, 84% (12), 20% (19).
a, b
c
O
O
X
X
BnO
BnO
HO
HO
X
OBn
OH
OBn
OH
50 : X = S
51 : X = O
14a : X = S
15 : X = O
52 : X = S
53 : X = O
Scheme 7. Reagents and conditions: (a) n-BuLi (1.6 M in hexane), THF, À78 °C then 43; (b) Et3SiH, BF3ÁOEt2, CH2Cl2, 0 °C, 60% (2 steps) (52), 62% (2 steps) (53); (c) BCl3 (1.0 M
in heptane), pentamethylbenzene, CH2Cl2, À78 °C, 60% (14a), 52% (15).

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3267
a, b
c
O
OTBDPS
O
OTBDPS
BnO
BnO
AcO
AcO
OBn
OAc
OBn
OAc
41
54
d
O
OH
O
Br
AcO
AcO
AcO
AcO
OAc
OAc
OAc
OAc
55
56
Scheme 8. Reagents and conditions: (a) 10% Pd/C, H2, THF–MeOH, rt; (b) Ac2O, DMAP, pyridine, rt, 98% (2 steps); (c) TBAF (1.0 M in THF), THF, rt, 44%; (d) CBr4, PPh3, CH2Cl2,
rt, 71%.
a, b
c
O
O
N
N
HO
HO
AcO
AcO
N
OH
OAc
OH
OAc
57
16
58
Scheme 9. Reagents and conditions: (a) n-BuLi (1.6 M in hexane), n-Bu3SnCl, THF, 0 °C to rt, 96% (b) 56, Pd2(dba)3, 2-(dicyclohexylphosphino)biphenyl, KF, Cs2CO3, dioxane,
60 °C, 51%; (c) NaOMe, MeOH-THF, rt, 61%.
Ar
Ar
a
b
O
O
AcO
AcO
HO
HO
56
OAc
OH
OAc
OH
N
N
59 : Ar =
60 : Ar =
61 : Ar =
13 : Ar =
17 : Ar =
18 : Ar =
N
N
N
N
*
*
*
*
S
N
S
N
*
*
O
O
Scheme 10. Reagents and conditions: (a) Zn, 1,2-dibromoethane, TMSCl, reflux then Ar-X (X = Cl or SMe), Pd(PPh3)4, reflux, 75% (59), 47% (60), 31% (61); (b) NaOMe, MeOH,
rt, 32% (13), 69% (17), 72% (18).
halogen exchange to gluconolactone 23 followed by the reduction of
lactol and removal of the benzyl groups afforded halogenated deriv-
atives 14d, 14e, 14h and 14i.
with a pyridine (12) and a pyrazine (13) resulted in complete loss
of the inhibitory activity toward SGLT2, indicating that nitrogen-
containing heteroaromatics are unfavorable at the terminal ben-
zene ring position. This tendency was also seen when replacing
with fused heteroaromatics. Conversion of the terminal benzene
ring in compound 5 to nitrogen-containing heteroaromatic, such
as an indole (16) a benzothiazole (17), a benzoxazole (18) and a
benzimidazole (19), also resulted in a significant decrease of the
inhibitory activity toward SGLT2. Among these heteroaryl deriva-
tives, the benzothiophene derivative 14a was a potent SGLT2
inhibitor with a good selectivity versus SGLT1. On the basis of
these results, we selected 14a as the lead compound for further
optimizations.
We next studied the effects of the substitution groups on the
central benzene ring of compound 14a (Table 3). Substitution of
hydroxyl (14b) or methoxy (14c) groups at the ortho position to
the glycoside of the benzene ring (6-position; R1) were found to
effectively increase inhibitory activity against SGLT2 (IC50 values
of 9.8 and 13 nM, respectively) while retaining a good selectivity
versus SGLT1 (107-fold and 510-fold, respectively). Additionally,
the introduction of a fluorine atom (14d) maintained the potency
of 14a, while that of a chlorine atom (14e) led to a three-fold de-
crease. These results indicates that the introduction of oxy-func-
tional groups onto this position should improve the inhibitory
activity against SGLT2. On the other hand, similar hydroxyl (14f)
or methoxy (14g) group substitutions at the para position to the
3. Result and discussion
The in vitro SGLT inhibitory potential (IC50) of all synthesized
compounds was assessed by monitoring the inhibition of accumu-
lating [14C] methyl-
a-D-glucopyranoside (AMG) in Chinese ham-
ster ovary cells expressing human SGLT2 or SGLT1.32
Compound 5 was found to be a very potent SGLT2 inhibitor
with an IC50 value of 10 nM and also to have a excellent SGLT2
selectivity versus SGLT1 (1000-fold). Table 1 shows the results of
replacing the central benzene ring in 5 with various heteroaromat-
ics. Although replacement with a thiophene ring (8) or a pyrrole
ring (9) caused a decrease in inhibitory activity (IC50 values of
100 and 70 nM, respectively), the decrease was not extreme and
both structures had a good selectivity versus SGLT1 (160-fold,
230-fold, respectively). These results suggest their utility as SGLT2
inhibitors. Replacement with a pyridine or a pyrazine (10 and 11)
resulted in a much more significant decrease in SGLT2 inhibitory
activity (IC50 value of 610 and 4900 nM, respectively), indicating
that lipophilic aromatics are preferred at this position when
designing SGLT2 inhibitors.
Next, we investigated the effects of replacing the terminal ben-
zene ring of 5 with various heteroaromatics (Table 2). Replacement

3268
M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
R1
Br
R2
R1
Br
R2
a
CHO
CHO
62 : R1 = OH, R2 = H
63 : R1 = H, R2 = OH
64 : R1 = OMOM, R2 = H
65 : R1 = H, R2 = OMOM
R1
R2
R1
Br
R2
b, c
d, e
f
O
S
BnO
BnO
S
S
OBn
OBn
66 : R1 = OMOM, R2 = H
67 : R1 = H, R2 = OMOM
50
68 : R1 = OMOM, R2 = H
69 : R1 = H, R2 = OMOM
R1
R2
R1
R2
h
O
O
S
S
BnO
HO
HO
BnO
OBn
OH
OBn
OH
70 : R1 = OH, R2 = H
14b : R1 = OH, R2 = H
71 : R1 = H, R2 = OH
14f : R1 = H, R2 = OH
g
R1
R2
R1
R2
h
O
O
S
S
HO
HO
BnO
BnO
OH
OBn
OH
OBn
72 : R1 = OMe, R2 = H
14c : R1 = OMe, R2 = H
73 : R1 = H, R2 = OMe
14g : R1 = H, R2 = OMe
Scheme 11. Reagents and conditions: (a) NaH, MOMCl, DMF, rt, 91% (64), 98% (65); (b) n-BuLi (1.6 M in hexane), THF, À78 °C then 64 or 65; (c) Et3SiH, BF3ÁOEt2, CH2Cl2,
À20 °C, 86% (2 steps) (66), 76% (2 steps) (67); (d) n-BuLi (1.6 M in hexane), THF, À78 °C then 23; (e) Et3SiH, BF3ÁOEt2, CH2Cl2, À20 °C, 58% (2 steps) (68), 14% (2 steps) (69); (f)
HCl (4.0 M in dioxane) , 91% (70), 82% (71); (g) K2CO3, MeI, DMF, rt , 95% (72), 92% (73); (h) BCl3 (1.0 M in heptane), pentamethylbenzene, CH2Cl2, À78 °C, 45% (14b), 29% (14c)
, 73% (14f), 27% (14g).
R1
R2
R1
Br
R2
a, b
c, d
O
S
BnO
BnO
S
S
OBn
OBn
74 : R1 = F, R2 = H
75 : R1 = Cl, R2 = H
76 : R1 = H, R2 = F
77 : R1 = H, R2 = Cl
50
78 : R1 = F, R2 = H
79 : R1 = Cl, R2 = H
80 : R1 = H, R2 = F
81 : R1 = H, R2 = Cl
R1
R2
e
O
S
HO
HO
OH
OH
14d : R1 = F, R2 = H
14e : R1 = Cl, R2 = H
14h : R1 = H, R2 = F
14i : R1 = H, R2 = Cl
Scheme 12. Reagents and conditions: (a) n-BuLi (1.6 M in hexane), THF, À78 °C then benzaldehydes; (b) Et3SiH, BF3ÁOEt2, CH2Cl2, 0 °C, 36% (2 steps) (74), 48% (2 steps) (75) ,
64% (2 steps) (76), 46% (2 steps) (77); (c) n-BuLi (1.6 M in hexane), THF, À78 °C then 43; (d) Et3SiH, BF3ÁOEt2, CH2Cl2, 0 °C, 22% (2 steps) (78), 34% (2 steps) (79) , 61% (2 steps)
(80), 14% (2 steps) (81); (e) BCl3 (1.0 M in heptane), pentamethylbenzene, CH2Cl2, À78 °C, 24% (14d), 86% (14e) , 64% (14h) , 70% (14i).
glycoside of the benzene ring (4-position; R2) resulted in a poor
selectivity versus SGLT1. Substitution with a fluorine atom at this
position (14h) resulted in a very good in vitro profile with an
IC50 value of 7.4 nM and a 254-fold selectivity versus SGLT1, while
introduction of a chlorine atom (14i) improved the inhibitory
activity against SGLT2 significantly (IC50 = 3.7 nM), but with a con-
sequent loss of selectivity versus SGLT1 (47-fold).
Among the aforementioned benzothiophene derivatives, com-
pound 14h was chosen for further in vivo studies. As shown in
Figure 2, single oral doses (0.01–10 mg/kg) of 14h induced urinary

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3269
Table 1
Table 3
In vitro inhibitory activity and selectivity of C-glucosides 5–11
In vitro inhibitory activity and selectivity of c-glucosides with benzothiophene 14a–i
R1
R2
4
R
6
A
O
O
HO
S
HO
HO
HO
OH
OH
OH
OH
Compound
A
R
hSGLT2
Selectivity vs hSGLT1a (fold)
Compound
R1
R2
hSGLT2
Selectivity vs hSGLT1a
(fold)
a
IC50 (nM)
a
IC50 (nM)
14a
14b
14c
14d
14e
14f
14g
14h
14i
H
H
H
H
H
H
OH
OMe
F
Cl
30
9.8
13
47
92
75
14
7.4
3.7
210
107
510
110
120
43
11
254
47
5
8
Et
10
1000
160
OH
OMe
F
Cl
H
H
H
H
S
OMe
Et
100
9
70
610
230
>160
>20
N
H
10
11
Et
Et
N
N
a
The data were obtained from at least two independent experiments.
4900
N
a
The data were obtained from at least two independent experiments.
has good bioavailability with a value of 71.7% (Table 4). Further-
more, the extensive blood glucose lowering effect of 14h should re-
flect excellent pharmacokinetic properties in vivo as well as strong
inhibitory activity against SGLT2.
Table 2
In vitro inhibitory activity and selectivity of C-glucosides 12–19
A
4. Conclusion
O
HO
HO
OH
The synthesis and structure–activity relationships (SARs) of C-
glucosides with various heteroaromatics as SGLT2 inhibitors have
been explored. Based on these SAR studies, the benzothiophene
derivative compound 14a was found to be a potent and selective
SGLT2 inhibitor. Further optimization of compound 14a culmi-
nated in the discovery of a novel compound, (1S)-1,5-anhydro-1-
OH
Compound
A
hSGLT2
Selectivity vs hSGLT1a (fold)
a
IC50 (nM)
12
13
>100,000
>100,000
—
N
N
[3-(1-benzothiophen-2-ylmethyl)-4-fluorophenyl]-D-glucitol
(14h), that is a highly potent and selective inhibitor for SGLT2. Oral
administration of compound 14h caused a remarkable increase in
urinary glucose excretion and anti-hyperglycemic effects in the
diabetic models KK-Ay mice and STZ rats. These findings, combined
with its favorable pharmacokinetic profile, have prompted clinical
evaluation of 14h. Currently, this benzothiophene derivative (Ipra-
gliflozin, ASP1941) is being developed for the treatment of type 2
diabetes mellitus.
––
N
S
O
N
14a
15
30
210
127
675
16
6300
7
5. Experimental
5.1. Chemistry
N
17
18
650
130
>43
S
N
1H NMR and 13C NMR spectra were obtained on a JEOL
JNM-EX400 spectrometer and the chemical shifts are
2300
O
N
expressed in
d (ppm) values with tetramethylsilane as an
19
>100,000
—
internal standard. Abbreviations of 1H NMR signal patterns
are as follows: s, singlet; d, doublet; dd, double doublet;
ddd, double double doublet; dt, double triplet; t, triplet; q,
quartet; m, multiplet; br, broad. Mass spectra were obtained
on a JEOL JMS-DX300 or HITACHI M-80 spectrometer. Column
chromatography on silica gel was performed with Kieselgel 60
(E. Merck).
N
a
The data were obtained from at least two independent experiments.
glucose excretion in a dose-dependent manner in both normal and
in KK-Ay mice, a type 2 diabetes model.29 To assess antihyperglyce-
mic effects, KK-Ay mice and streptozotocin-induced diabetic rats
(STZ rats, a type 1 diabetes model) were used to evaluate the effi-
cacy of 14h for lowering blood glucose levels. Figure 3 shows that
single administrations of 14h (0.1, 0.3 and 1 mg/kg) dose-depen-
dently reduces blood glucose level in both KK-Ay mice and STZ
rats.29
5.1.1. (4-Bromo-2-thienyl)(4-methoxyphenyl)methanol (21)
To an ice-cooled solution of 4-bromothiophene-2-carbaldehyde
(1.91 g, 10.0 mmol) in THF (20 mL) was added 4-meth-
oxyphenylmagnesiumbromide (0.5 M in THF; 24 mL, 12.0 mmol)
and the mixture was stirred at 0 °C for 2 h. The reaction mixture
was quenched by adding saturated aqueous ammonium chloride
Administration of a single 0.3 mg/kg dose intravenously and a
single 1 mg/kg dose orally to rats revealed that compound 14h

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M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
Figure 2. Effects of single oral dosings of compound 14h on urinary glucose excretion in Institute of Cancer Research normal mice and KK-Ay mice. Values are mean or
mean SEM for four animals in each group. Each parameter was analyzed statistically over 24 h. ⁄p<0.05 vs. vehicle using Dunnett’s multiple range test.
Figure 3. Effects of single oral dosings of 14h on blood glucose level in KK-Ay mice and STZ rats. (A) Change in blood glucose levels. (B) Suppression of glucose AUC. Values are
expressed as mean SEM for four animals in each group. ⁄p<0.05 versus vehicle using Dunnett’s multiple range test.
Table 4
Pharmacokinetic properties of 14h in rats
Route
Dose (mg/kg)
t1/2 (h)
Tmax (h)
Cmax (ng/mL)
AUC0–24h (ng⁄h/mL)
686
AUCinf (ng⁄h/mL)
692
CLtot (L/h/kg)
0.43
Vdss (L/kg)
BA%)
71.7
iv
po
0.3
1
3.85
3.61
1.68
1
331
1638
1654
solution and extracted with Et2O. The organic layer was dried over
Na2SO4, filtered and evaporated in vacuo. The resulting residue was
purified by column chromatography on silica gel (EtOAc–hexane)
to give the titled compound 21 (2.86 g, 96%) as a light brown solid.
1H NMR (DMSO-d6) d: 3.32 (1H, s), 3.74 (3H, s), 5.85 (1H, d,
J = 4.0 Hz), 6.26 (1H, d, J = 4.0 Hz), 6.80 (1H, d, J = 1.6 Hz), 6.91
(2H, d, J = 8.4 Hz), 7.31 (2H, d, J = 8.4 Hz), 7.49 (1H, d, J = 1.6 Hz).
MS (FAB) m/z: 300 (M++H), calcd for C12H11BrO2S: 299
5.1.2. 4-Bromo-2-(4-methoxybenzyl)thiophene (22)
To a cold (À78 °C) solution of 21 (2.78 g, 9.29 mmol) in CH2Cl2
(60 mL) was added Et3SiH (3.0 mL, 19.0 mmol) and BF3ÁOEt2

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3271
(1.3 mL, 10.0 mmol) and the mixture was warmed up to À20 °C
and stirred at À20 °C for 2 h. The reaction mixture was quenched
by adding saturated aqueous sodium bicarbonate solution and ex-
tracted with CHCl3. The organic layer was dried over Na2SO4, fil-
tered and evaporated in vacuo. The resulting residue was purified
by column chromatography on silica gel (EtOAc–hexane) to give
the titled compound 22 (1.85 g, 70%) as a colorless oil.
1H NMR (CDCl3) d: 1.22 (3H, t, J = 6.9 Hz), 2.62 (2H, q, J = 7.5,
15 Hz), 3.44 (2H, s), 5.96–6.01 (1H, m), 6.14 (1H, dd, J = 2.7,
5.7 Hz), 6.65 (1H, dd, J = 2.7, 5.7 Hz), 7.00–7.28 (4H, m). MS (FAB)
m/z: 186 (M++H), calcd for C13H15N: 185.
5.1.6. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[5-(4-ethylb-
enzyl)-1H-pyrrol-2-yl]-D-glucitol (28)
1H NMR (CDCl3) d: 3.80 (3H, s), 4.04 (2H, s), 6.68 (1H, d,
J = 1.6 Hz), 6.85 (2H, d, J = 9.6 Hz), 7.02 (1H, d, J = 1.6 Hz), 7.14 (2H,
d, J = 9.6 Hz). MS (FAB) m/z: 284 (M++H), calcd for C12H11BrOS: 283
To a solution of 26 (4.14 g, 22.3 mmol) in THF (10 mL) was
added iPrMgBr (0.71 M in THF; 27.6 mL, 21.0 mmol) and the mix-
ture was stirred at rt for 2 h. To the reaction mixture was added
27 (3.80 g, 7.0 mmol) and the mixture was stirred at rt for 1.5 h.
To the reaction mixture was added saturated aqueous ammonium
chloride solution then extracted with EtOAc. The organic layer was
washed with brine, dried over Na2SO4, filtered and evaporated in
vacuo. The resulting residue was purified by column chromatogra-
phy on silica gel (EtOAc–hexane) to give the titled compound 28
(1.89 g, 38%) as a brown oil.
5.1.3. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[5-(4-methox-
ybenzyl)-3-thienyl]-D-glucitol (24)
To a cold (À78 °C) solution of 22 (1.78 g, 6.29 mmol) in THF–
toluene (1:1; 40 mL) was added n-BuLi (1.60 M in hexane;
4.0 mL, 6.4 mmol) and the mixture was stirred at À78 °C for
10 min. To the reaction mixture was added a solution of 23 in
THF–toluene (1:1; 30 mL) and the mixture was stirred at À78 °C
for 2 h. The reaction mixture was quenched by adding saturated
aqueous ammonium chloride solution and extracted with Et2O.
The organic layer was dried over Na2SO4, filtered and evaporated
in vacuo. The resulting residue was purified by column chromatog-
raphy on silica gel (EtOAc–hexane) to give a lactol (2.98 g, 71%) as a
pale yellow oil. To a cold (À78 °C) solution of the lactol obtained
above (2.26 g, 3.04 mmol) in CH2Cl2 (50 mL) was added Et3SiH
(1.46 mL, 9.14 mmol) and BF3ÁOEt2 (0.42 mL, 3.30 mmol) and the
mixture was warmed up to À20 °C and stirred at À20 °C for
4.5 h. The reaction mixture was quenched by adding saturated
aqueous sodium bicarbonate solution and extracted with CHCl3.
The organic layer was dried over Na2SO4, filtered and evaporated
in vacuo. The resulting residue was purified by column chromatog-
raphy on silica gel (EtOAc–hexane) to give the titled compound 24
(2.30 g, quant.) as a colorless oil.
1H NMR (CDCl3) d: 1.19 (3H, t, J = 7.5 Hz), 2.59 (2H, q, J = 7.8,
15 Hz), 3.40–3.98 (8H, m), 4.22 (1H, d, J = 9.6 Hz), 4.33 (1H, d,
J = 9.6 Hz), 4.45–4.62 (4H, m), 4.80–4.96 (3H, m), 5.95 (1H, t,
J = 3.3 Hz), 6.18 (1H, t, J = 3.3 Hz), 6.85–7.33 (24H, m), 8.17 (1H,
s). MS (FAB) m/z: 708 (M++H), calcd for C44H49NO5: 707.
5.1.7. (1S)-1,5-Anhydro-1-[5-(4-ethylbenzyl)-1H-pyrrol-2-yl]-D-
glucitol (9)
To a solution of 28 (400 mg, 0.57 mmol) in MeOH–EtOAc (1:5,
12 mL) was added Pd(OH)2 (20 wt% on carbon; 150 mg) and the
mixture was stirred at rt for 86 h under H2 atmosphere. The reac-
tion mixture was filtered through celite and the filtrate was evap-
orated in vacuo. The resulting residue was purified by column
chromatography on silica gel (MeOH–CHCl3) to give the titled com-
pound 9 (25 mg, 13%) as a white solid.
1H NMR (CD3OD) d: 1.19 (3H, t, J = 7.8 Hz), 2.58 (2H, q,
J = 7.8 Hz), 3.24–3.46 (4H, m), 3.65 (1H, dd, J = 4.8, 11.7 Hz),
3.80–3.86 (4H, m), 4.15 (1H, d, J = 9.3 Hz), 5.73 (1H, d, J = 3.0 Hz),
6.02 (1H, d, J = 3.0 Hz), 7.07 (2H, d, J = 8.3 Hz), 7.12 (2H, d,
J = 8.3 Hz). MS (FAB) m/z: 348 (M++H), calcd for C19H25NO5: 347.
1H NMR (CDCl3) d: 3.46–3.57 (2H, m), 3.72–3.77 (7H, m), 3.96
(1H, d, J = 10.3 Hz), 4.06 (2H, s), 4.27 (1H, d, J = 10.3 Hz), 4.43–
4.65 (4H, m), 4.81–4.95 (3H, m), 6.79 (2H, d, J = 6.3 Hz), 6.87 (1H,
s), 6.97–7.01 (2H, m), 7.12–7.34 (21H, m). MS (ESI) m/z: 749
(M++Na), calcd for C46H46O6S: 726.
5.1.8. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-(6-bromopyri-
din-2-yl)-D-glucitol (30)
5.1.4. (1S)-1,5-Anhydro-1-[5-(4-methoxybenzyl)-3-thienyl]-D-
glucitol (8)
To a cold (À78 °C) solution of 2,6-dibromopyridine (29) (7.10 g,
30.0 mmol) in THF (90 mL) was added n-BuLi (1.60 M in hexane;
18.9 mL, 30.0 mmol) and the mixture was stirred at À78 °C for
25 min. To the reaction mixture was added a solution of 23
(15.4 g, 28.5 mmol) in THF (30 mL) and the mixture was stirred
at À78 °C for 3.5 h. The reaction mixture was poured into water
and extracted with EtOAc. The organic layer was washed with
Brine, dried over MgSO4, filtered and evaporated in vacuo. The
resulting residue was purified by column chromatography on silica
gel (EtOAc–hexane) to give lactol (13.3 g, 67%) as a pale yellow oil.
To a cold (0 °C) solution of the lactol obtained above (13.2 g,
18.9 mmol) in CH2Cl2 (135 mL) was added Et3SiH (30.2 mL,
189 mmol) and trifluoroacetic acid (TFA) (14.5 mL, 189 mmol)
and the mixture was warmed up to rt and stirred at rt for 7 days.
The reaction mixture was quenched by adding saturated aqueous
sodium bicarbonate solution and extracted with CHCl3. The organic
layer was dried over MgSO4, filtered and evaporated in vacuo. The
resulting residue was purified by column chromatography on silica
gel (EtOAc–hexane) to give the titled compound 30 (9.05 g, 70%) as
a colorless oil.
To a cold (À78 °C) solution of 24 (0.73 g, 1.00 mmol) in CH2Cl2
(35 mL) were added pentamethylbenzene (2.22 g, 15.0 mmol)
and BCl3 (1.0 M in heptane; 5.0 mL, 5.0 mmol) and the mixture
was stirred at À78 °C for 4 h. The reaction mixture was quenched
by adding MeOH at À78 °C then warmed up to rt. The mixture
was evaporated in vacuo and the resulting residue was purified
by column chromatography on silica gel (MeOH–CHCl3) to give
the titled compound 8 (0.167 g, 46%) as a white solid.
1H NMR (CD3OD) d: 3.32–3.45 (4H, m), 3.66 (1H, dd, J = 5.3,
11.7 Hz), 3.76 (3H, s), 3.86 (1H, d, J = 11.7 Hz), 4.04 (2H, s), 4.15
(1H, d, J = 9.3 Hz), 6.80–6.92 (3H, m), 7.13–7.18 (3H, m). MS
(FAB) m/z: 367 (M++H), calcd for C18H22O6S: 366
5.1.5. 2-(4-Ethylbenzyl)-1H-pyrrole (26)
To pyrrole 25 (8.00 g, 119 mmol) was added iPrMgBr (0.71 M in
THF; 202 mL, 143 mmol) and the mixture was stirred at rt for 1 h,
then the solvent was removed in vacuo. The resulting residue was
dissolved in benzene (150 mL) and 4-ethylbenzylbromide (25.9 g,
130 mmol) was added to the solution, then the mixture was stirred
at 60 °C for 1 h. To the reaction mixture was added saturated aque-
ous ammonium chloride solution then extracted with EtOAc. The
organic layer was washed with brine, dried over Na2SO4, filtered
and evaporated in vacuo. The resulting residue was purified by col-
umn chromatography on silica gel (EtOAc–hexane) to give the
titled compound 26 (4.19 g, 19%) as a brown oil.
1H NMR (CDCl3) d: 3.62 (1H, dt, J = 4.0, 9.6 Hz), 3.73–3.78 (2H,
m), 3.82–3.87 (2H, m), 4.08–4.13 (2H, m), 4.37 (1H, d, J = 9.2 Hz),
4.50–4.62 (4H, m), 4.83–4.96 (3H, m), 6.93–6.98 (2H, m), 7.15–
7.36 (18H, m), 7.40–7.53 (3H, m). MS (FAB) m/z: 681 (M++H), calcd
for C39H38BrNO5: 680

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M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
5.1.9. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-(6-carboxypyr-
idin-2-yl)- -glucitol (31)
resulting residue was purified by column chromatography on silica
gel (EtOAc–hexane) to give the title compound (33) (274 mg, 90%)
as a colorless oil.
D
To a solution of 30 (1.15 g, 1.67 mmol) in DMSO–MeOH (2:3;
10.0 mL) was added Pd(OAc)2 (135 mg, 0.6 mmol), diphenylphos-
phino propane (248 mg, 0.6 mmol) and triethylamine (0.61 mL,
4.40 mmol). The mixture was stirred at 70 °C under CO atmo-
sphere for 24 h. The reaction mixture was evaporated in vacuo
and to the resulting residue was added EtOAc. The insoluble
portion was filtered through celite and the filtrate was washed
with water. The organic layer was dried over MgSO4, filtered
and evaporated in vacuo. The resulting residue was purified by
column chromatography on silica gel (EtOAc–hexane) to give
yellow oil (0.84 g, 76%). To a solution of this yellow oil (0.80 g,
1.21 mmol) in THF–MeOH (1:1; 16 mL) was added 1 M aqueous
sodium hydroxide solution (8.0 mL) and the mixture was stirred
at rt for 2 h and the reaction mixture was evaporated in vacuo .
The resulting residue was dissolved in CHCl3 then washed with
1 M aqueous hydrogen chloride solution. The organic layer was
dried over MgSO4, filtered and evaporated in vacuo then dried
up to give the titled compound 31 (0.78 g, quant.) as a colorless
oil.
1H NMR (CDCl3) d: 1.15 (3H, t, J = 6.8 Hz), 2.56 (2H, q, J = 6.8 Hz),
3.62–4.01 (7H, m), 4.37–4.68 (5H, m), 4.84–4.97 (3H, m), 5.72 (1H,
br s), 6.76–6.85 (2H, m), 7.02–7.36 (24H, m), 7.57 (1H, t, J = 8.0 Hz).
MS (FAB) m/z: 736 (M++H), calcd for C48H49NO6: 735.
5.1.12. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[6-(4-ethylb-
enzyl)pyridin-2-yl]-D-glucitol (34)
To a solution of 33 (310 mg, 0.41 mmol) in THF (15 mL) was
added NaH (55% on mineral oil; 36 mg, 0.81 mmol). The mixture
was stirred at ambient temp. for 10 min, then CS2 (0.184 mL,
3.05 mmol) was added and the mixture was stirred at rt for 1 h.
To the reaction mixture was added MeI (0.05 mL, 0.81 mmol) and
the mixture was stirred at rt for 2 h. The reaction mixture was di-
luted with EtOAc then washed with brine. The organic layer was
dried over MgSO4, filtered and evaporated in vacuo. To a solution
of resulting residue in toluene (10 mL) was added n-Bu3SnH
(0.55 mL, 2.03 mmol) and
a,a’-azoisobutyronitrile (AIBN) (33 mg,
0.20 mmol) and the mixture was stirred under reflux condition
5 h. The reaction mixture was cooled down to rt then evaporated
in vacuo. The resulting residue was purified by column chromatog-
raphy on silica gel (EtOAc–hexane) to give the title compound (34)
(205 mg, 70%) as a colorless oil.
1H NMR (CDCl3) d: 3.62–3.97 (8H, m), 4.41–4.65 (4H, m) 4.87
(1H, d, J = 10.8 Hz), 4.95 (2H, s), 6.75–6.78 (2H, m), 7.07–7.38
(18H, m), 7.61 (1H, d, J = 8.0 Hz), 7.87 (1H, t, J = 8.0 Hz), 8.13
(1H, d, J = 8.0 Hz). MS (FAB) m/z: 646 (M++H), calcd for
1H NMR (CDCl3) d: 1.08 (3H, t, J = 8.2 Hz), 2.47 (2H, q, J = 8.2 Hz),
3.54–3.90 (7H, m), 4.05 (2H, q, J = 15.2 Hz), 4.29–4.55 (5H, m), 4.79
(1H, d, J = 10.4 Hz), 4.83 (2H, q, J = 11.2 Hz), 6.71–6.74 (2H, m),
6.92–7.28 (24H, m), 7.46 (1H, t, J = 7.6 Hz). MS (FAB) m/z: 720
(M++H), calcd for C48H49NO5: 719.
C40H39NO7: 645.
5.1.10. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-{6-[methoxy-
(methyl)carbamoyl]pyridin-2-yl- -glucitol (32)
D
To a solution of 31 (2.98 g , 4.41 mmol) in DMF (18 mL) was
added N,O-dimethylhydroxylamine hydrochloride (646 mg,
6.62 mmol),
triethylamine
(0.93 mL,
6.62 mmol),
HOBt
5.1.13. (1S)-1,5-Anhydro-1-[6-(4-ethylbenzyl)pyridin-2-yl]-D-
glucitol (10)
(743 mg, 4.85 mmol) and WSC HCl (1.27 g, 6.62 mmol) and
the mixture was stirred at rt overnight. The reaction mixture
was diluted with EtOAc then washed with water and saturated
aqueous sodium bicarbonate solution. The organic layer was
dried over MgSO4, filtered and evaporated in vacuo. The result-
ing residue was purified by column chromatography on silica
gel (EtOAc–hexane) to give the titled compound 32 (2.55 g,
84%) as a colorless oil.
The title compound was prepared in the same manner as
described for 8 using 34 instead of 24 in 81% yield.
1H NMR (CD3OD) d: 1.19 (3H, t, J = 7.6 Hz), 2.59(2H, q,
J = 7.6 Hz), 3.41–3.62 (4H, m), 3.74 (1H, dd, J = 4.8, 12.2 Hz),
3.91(1H, d, J = 11.3 Hz), 4.10 (2H, s), 4.28 (1H, d, J = 8.8 Hz), 7.07–
7.18 (5H, m), 7.41 (1H, d, J = 7.8 Hz), 7.71 (1H, t, J = 7.8 Hz). MS
(FAB) m/z: 360 (M++H), calcd for C20H25NO5: 359.
1H NMR (CDCl3) d: 3.37 (3H, s), 3.61–3.89 (9H, m), 3.95 (1H, d,
J = 10.8 Hz), 4.41–4.65 (5H, m), 4.85–4.97 (3H, m), 6.87 (2H, m),
7.12–7.35 (19H, m), 7.46 (1H, d, J = 8.4 Hz), 7.77 (1H, t,
J = 8.4 Hz). MS (FAB) m/z: 689 (M++H), calcd for C42H44N2O7:
688.
5.1.14. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-(3,5-dichloro-
pyrazin-2-yl)-D-glucitol (36)
To a cold (À78 °C) solution of iPr2NH (2.34 g, 23.1 mmol) in
THF (60 mL) was added n-BuLi (1.60 M in hexane; 13.2 mL,
21.0 mmol), then the mixture was warmed up to 0 °C and stirred
for 30 min. The mixture was cooled down to À78 °C and 2,6-
dichloropyrimidine (35) (2.98 g, 20.0 mmol) was added to the
mixture. After stirring at À78 °C for 10 min., the solution was
added to a solution of 23 (10.8 g, 20.0 mmol) in THF (100 mL)
and the mixture was stirred at À78 °C for 3 h. The reaction mix-
ture was diluted with saturated aqueous ammonium chloride
solution then extracted with Et2O. The organic layer was dried
over MgSO4, filtered and evaporated in vacuo. The resulting resi-
due was purified by column chromatography on silica gel
(EtOAc–hexane) to give lactol (9.07 g, 66%). The title compound
was prepared in the same manner as described for 30 using this
lactol in 28% yield.
5.1.11. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-{6-[(4-ethyl-
phenyl)(hydroxy)methyl]pyridin-2-yl-D-glucitol (33)
To a cold (À78 °C) solution of 32 (440 mg, 0.639 mmol) in
CH2Cl2 (30 mL) was added diisobutylalminiumhydride (1.0 M in
hexane; 0.96 mL, 0.96 mmol) and the mixture was stirred at 0 °C
for 3 h. To the reaction mixture was added saturated aqueous
ammonium chloride solution then the resulting insoluble portion
was filtered through celite. The filtrate was extracted with CHCl3
and the organic layer was dried over MgSO4, filtered and evapo-
rated in vacuo. The resulting residue was purified by column chro-
matography on silica gel (EtOAc–hexane) to give aldehyde
(250 mg, 62%) as a colorless oil. To a cold (À30 °C) solution of 1-
ethyl-4-iodobenzene (0.29 mL, 1.98 mmol) in THF (10 mL) was
added iPrMgCl (2.0 M in THF; 0.95 mL, 1.90 mmol) and the mixture
was stirred at À30 °C for 2 h. To the reaction mixture was added a
solution of aldehyde obtained above (250 mg, 0.40 mmol) in THF
(10 mL) and the mixture was stirred at rt for 2.5 h. To the reaction
mixture was added saturated aqueous ammonium chloride solu-
tion then extracted with EtOAc. The organic layer was washed with
brine, dried over MgSO4, filtered and evaporated in vacuo. The
1H NMR (CDCl3) d: 3.66–3.73 (4H, m), 3.91 (1H, t, J = 9.2 Hz),
4.07 (1H, t, J = 9.2 Hz), 4.38 (1H, d, J = 11.6 Hz), 4.48 (1H, d,
J = 12.0 Hz), 4.54 (1H, d, J = 12.0 Hz), 4.59 (1H, d, J = 10.8 Hz), 4.72
(1H, d, J = 11.6 Hz), 4.81 (1H, d, J = 9.2 Hz), 4.85 (1H, d,
J = 10.8 Hz), 4.96 (2H, s), 6.89 (2H, d, J = 7.2 Hz), 7.13–7.37 (18H,
m), 8.21 (1H, s). MS (FAB) m/z: 671 (M++H), calcd for
C38H36Cl2N2O5: 670.

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3273
5.1.15. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[3,5-dichloro-
6-(4-ethylbenzyl)pyrazin-2-yl]- -glucitol (37)
1H NMR (CDCl3) d: 1.10 (9H, s), 4.72 (2H, s), 7.16–7.27 (2H, m),
7.35–7.48 (8H, m), 7.66–7.69 (4H, m). MS (FAB) m/z: 425 (M+),
calcd for C23H25BrOSi: 425.
D
To a cold (À78 °C) solution of n-BuLi (1.60 M in hexane;
2.15 mL, 3.42 mmol) in THF (20 mL) was slowly added 2,2,6,6-tet-
ramethylpiperidine (0.64 mL, 3.80 mmol) and the mixture was
warmed up to 0 °C and then stirred for 1 h. The mixture was cooled
down to À78 °C, then a solution of 36 (2.09 g, 3.11 mmol) in THF
(20 mL) was added to the mixture and stirred at À78 °C for 1 h.
To the reaction mixture was added 4-ethylbenzaldehyde
(1.28 mL, 9.34 mmol) and the mixture was stirred at À78 °C for
1.5 h. To the reaction mixture was added saturated aqueous
ammonium chloride solution and Et2O then the organic layer
was separated. The organic layer was dried over MgSO4, filtered
and evaporated in vacuo. The resulting residue was purified by col-
umn chromatography on silica gel (EtOAc–hexane) to give alcohol
(0.84 g, 34%). The title compound was prepared in the same man-
ner as described for 30 using this alcohol in 63% yield.
5.1.19. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[3-({[tert-bu-
tyl(diphenyl)silyl]oxy}methyl)phenyl]-D-glucitol (41)
The title compound was prepared in the same manner as de-
scribed for 24 using 40 instead of 22 in 29% yield.
1H NMR (CDCl3) d: 1.09 (9H, s), 3.49–3.80 (7H, m), 4.22–4.97
(10H, m), 6.88–7.72 (34H, m). MS (FAB) m/z: 869 (M++H), calcd
for C56H60O6Si: 868.
5.1.20. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[3-(hydroxy-
methyl)phenyl]-D-glucitol (42)
To a solution of 41 (18.5 g, 21.3 mmol) in THF (200 mL) was
added tetrabutylammonium fluoride (1.0 M in THF; 30.8 mL,
20.8 mmol) and the mixture was stirred at rt for 30 min. The reac-
tion mixture was evaporated in vacuo and the resulting residue
was purified by column chromatography on silica gel (EtOAc–hex-
ane) to give the title compound (42) (6.17 g, 46%) as a white solid.
1H NMR (CDCl3) d: 3.50 (1H, t, J = 9.3 Hz), 3.60–3.87 (8H, m),
4.26 (1H, d, J = 9.3 Hz), 4.42 (1H, d, J = 10.6 Hz), 4.56 (1H, d,
J = 12.3 Hz), 4.62–4.67 (1H, m), 4.66 (2H, s), 4.87 (1H, d,
J = 10.6 Hz), 4.90–4.93 (1H, m), 4.96 (1H, d, J = 11.0 Hz), 6.89–
6.92 (2H, m), 7.18–7.42 (22H, m). MS (FAB) m/z: 631 (M++H), calcd
for C41H42O6: 630.
1H NMR (CDCl3) d: 1.10 (3H, t, J = 7.6 Hz), 2.50 (2H, q, J = 7.6 Hz),
3.64–3.68 (1H, m), 3.72–3.82 (3H, m), 3.90 (1H, t, J = 9.0 Hz), 4.10–
4.23 (4H, m), 4.49 (1H, d, J = 12.0 Hz), 4.59–4.66 (3H, m), 4.78 (1H,
d, J = 10.0 Hz), 4.86–4.97 (3H, m), 6.78 (2H, d, J = 6.8 Hz), 6.97 (2H,
d, J = 8.0 Hz), 7.09–7.33 (20H, m). MS (ESI) m/z: 789 (M++H), calcd
for C47H46Cl2N2O5: 788.
5.1.16. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[6-(4-ethylb-
enzyl)pyrazin-2-yl]-D-glucitol (38)
To a solution of 37 (0.10 g, 0.13 mmol) in MeOH–THF (3:1;
4.0 mL) was added Pd (10 wt% on carbon) (0.10 g) and Et3N
(0.035 mL, 0.25 mmol). The mixture was stirred at rt under H2
atmosphere for 22 h. The insoluble portion was filtered through
celite and washed with MeOH. The filtrate was evaporated in va-
cuo. The resulting residue was purified by column chromatography
on silica gel (EtOAc–hexane) to give the title compound (38)
(0.046 g, 50%) as a pale yellow oil.
5.1.21. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-(3-formylph-
enyl)-D-glucitol (43)
To a solution of 42 (4.12 g, 6.53 mmol) in chloroform (50 mL)
was added manganese (IV) oxide (MnO2) (28.4 g, 327 mmol) and
the mixture was stirred at rt for 1 day. The reaction mixture was
filtered through celite and the filtrate was evaporated in vacuo.
The resulting residue was purified by column chromatography on
silica gel (EtOAc–hexane) to give the title compound (43) (3.79 g,
92%) as a white solid.
1H NMR (CDCl3) d: 1.15 (3H, t, J = 7.8 Hz), 2.54 (2H, q, J = 7.8 Hz),
3.63–3.68 (1H, m), 3.74–3.81 (3H, m), 3.87 (1H, t, J = 9.0 Hz),
3.93–4.00 (2H, m), 4.11 (2H, s), 4.43 (1H, d, J = 9.6 Hz), 4.48 (1H,
d, J = 10.8 Hz), 4.53 (1H, d, J = 12.2 Hz), 4.59 (1H, d, J = 12.2 Hz),
4.62 (1H, d, J = 10.8 Hz), 4.87 (1H, d, J = 10.4 Hz), 4.92 (2H, s),
6.75 (2H, d, J = 8.4 Hz), 7.04 (2H, d, J = 8.4 Hz), 7.08–7.34 (20H,
m), 8.36 (1H, s), 8.48 (1H, s). MS (ESI) m/z: 721 (M++H), calcd for
1H NMR (CDCl3) d: 3.48 (1H, t, J = 9.2 Hz), 3.75–3.87 (5H, m),
4.32 (1H, d, J = 9.2 Hz), 4.47 (1H, d, J = 10.6 Hz), 4.54–4.68 (4H,
m), 4.87 (1H, d, J = 10.6 Hz), 4.94 (2H, m), 6.85–6.88 (2H, m),
7.13–7.52 (19H, m), 7.70 (1H, d, J = 7.7 Hz), 7.85 (1H, d,
J = 7.7 Hz), 7.93 (1H, brs), 9.97 (1H, s). MS (FAB) m/z: 651
(M++Na), calcd for C41H40O6: 628.
C47H48N2O5: 720.
5.1.22. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-{3-[hydroxy-
(pyridin-2-yl)methyl]phenyl}-D-glucitol (46)
5.1.17. (1S)-1,5-Anhydro-1-[6-(4-ethylbenzyl)pyrazin-2-yl]-D-
glucitol (11)
To a cold (À78 °C) solution of 2-bromopyridine (44) (774 mg,
4.87 mmol) in THF (25 mL) was added n-BuLi (1.60 M in hexane;
3.10 mL, 4.87 mmol) and the mixture was stirred at À78 °C for 1 h.
To the reaction mixture was added a solution of 43 (2.55 g,
4.06 mmol) in THF (60 mL) and the mixture was stirred at À78 °C
for 3 h. To the reaction mixture was added H2O and EtOAc, then the
organic layer was separated and washed with brine, dried over
MgSO4, filtered and evaporated in vacuo. The resulting residue was
purified by column chromatography on silica gel (EtOAc–hexane)
to give the title compound (46) (1.82 g, 63%) as a colorless oil.
1H NMR (CDCl3) d: 3.48–3.60 (2H, m), 3.71–3.81 (5H, m), 4.24
(1H, dd, J = 6.8, 9.6 Hz), 4.33 (1H, dd, J = J = 6.8, 9.6 Hz), 4.54 (1H,
t, J = 12.0 Hz), 4.61–4.65 (3H, m), 4.85–4.95 (2H, m), 5.23 (1H,
brs), 5.75 (1H, brs), 6.84–6.98 (4H, m) 7.00–7.50 (23H, m), 8.52
(1H, dd, J = 4.8, 9.6 Hz). MS (FAB) m/z: 708 (M++H), calcd for
The title compound was prepared in the same manner as de-
scribed for 8 using 38 instead of 24 in 43% yield.
1H NMR (CD3OD) d: 1.20 (3H, t, J = 7.8 Hz), 2.60 (2H, q,
J = 7.8 Hz), 3.45–3.56 (3H, m), 3.64 (1H, t, J = 9.1 Hz), 3.70–3.75
(1H, m), 3.89 (1H, dd, J = 1.4, 12.2 Hz), 4.17 (2H, s), 4.37 (1H, d,
J = 9.2 Hz), 7.13 (2H, d, J = 8.1 Hz), 7.19 (2H, d, J = 8.1 Hz), 8.40
(1H, s), 8.56 (1H, s). MS (ESI) m/z: 361 (M++H), calcd for
C19H22N2O5: 360.
5.1.18. [(3-bromobenzyl)oxy](tert-butyl)diphenylsilane (40)
To a cold (0 °C) solution of 3-bromophenylethanol (39) (50 g,
267 mmol) and imidazole (27 g, 401 mmol) in DMF (500 mL) was
added tert-butylchlorodiphenylsilane (83 mL, 320 mmol) and the
mixture was warmed up to rt then stirred at rt for 8 h. To the reac-
tion mixture was added saturated aqueous ammonium chloride
solution and EtOAc. The organic layer was separated and washed
with brine then dried over MgSO4, filtered and evaporated in va-
cuo. The resulting residue was purified by column chromatography
on silica gel (EtOAc–hexane) to give the title compound (40)
(117 g, quant.) as a white solid.
C38H36Cl2N2O5: 670, calcd for C46H45NO6: 707.
5.1.23. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-[3-(pyridin-2-
ylmethyl)phenyl]- -glucitol (48)
D
The title compound was prepared in the same manner as de-
scribed for 34 using 46 instead of 33 in 87% yield.

3274
M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
1H NMR (CDCl3) d: 3.48–3.81 (7H, m), 4.16 (2H, s), 4.22 (1H, d,
chromatography on silica gel (EtOAc–hexane) to give the title com-
pound (52) (2.04 g, 75%) as a light orange oil.
J = 9.6 Hz), 4.34 (1H, d, J = 10.4 Hz), 4.52–4.65 (3H, m), 4.85–4.94
(3H, m), 6.87–6.89 (2H, m), 7.00–7.06 (2H, m), 7.15–7.36 (22H,
m), 7.45 (1H, dt, J = 2.0, 7.2 Hz), 8.48–8.51 (1H, m). MS (FAB) m/z:
692 (M++H), calcd for C46H45NO5: 691.
1H NMR (CDCl3) d: 3.50–3.61 (2H, m), 3.73–3.81 (6H, m), 4.21
(2H, s), 4.30 (2H, q, J = 9.6 Hz), 4.59 (2H, q, J = 12.4 Hz), 4.86 (1H,
d, J = 10.8 Hz), 4.90 (2H, q, J = 10.8 Hz), 6.87–6.89 (2H, m), 6.97
(1H, s), 7.13–7.40 (24H, m), 7.66 (1H, d, J = 10.8 Hz), 7.68 (1H, d,
J = 10.8 Hz). MS (FAB) m/z: 747 (M++H), calcd for C49H46O5S: 746.
5.1.24. (1S)-1,5-Anhydro-1-[3-(pyridin-2-ylmethyl)phenyl]-D-
glucitol (12)
The title compound was prepared in the same manner as de-
scribed for 8 using 48 instead of 24 in 84% yield.
5.1.29. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-
phenyl]-D-glucitol (14a)
1H NMR (CD3OD) d: 3.32–3.49 (4H, m), 3.69 (1H, dd, J = 5.4,
12.2 Hz), 3.87 (1H, dd, J = 1.8, 12.2 Hz), 4.10 (1H, d, J = 9.3 Hz),
4.14 (2H, s), 7.17 (1H, dt, J = 2.1, 6.9 Hz), 7.18–7.31 (4H, m), 7.36
(1H, s), 7.73 (1H, dt, J = 2.1, 7.9 Hz), 8.40–8.43 (1H, m). MS (FAB)
m/z: 332 (M++H), calcd for C18H21NO5: 331.
The title compound was prepared in the same manner as de-
scribed for 8 using 52 instead of 24 in 60% yield.
1H NMR (CD3OD) d: 3.34–3.49 (4H, m), 3.67 (1H, dd, J = 5.4,
11.9 Hz), 3.87 (1H, d, J = 2.0, 11.9 Hz), 4.12 (1H, d, J = 9.3 Hz), 4.24
(2H, s), 7.06 (1H, s), 7.07–7.33 (5H, m), 7.40 (1H, s), 7.65 (1H, d,
J = 7.8 Hz), 7.72 (1H, d, J = 7.8 Hz). MS (FAB) m/z: 387 (M++H), calcd
for C21H22O5S: 386.
5.1.25. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-{3-[hydroxy-
(1-methyl-1H-benzimidazole-2-yl)methyl]phenyl}-D-glucitol
(47)
5.1.30. (1S)-1,5-Anhydro-1-[3-(1-benzofuran-2-ylmethyl)phe-
The title compound was prepared in the same manner as de-
scribed for 46 using 1-methyl-1H-benzimidazole (45) instead of
44 in 35% yield.
nyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (53)
The title compound was prepared in the same manner as de-
scribed for 52 using 51 instead of 50 in 62% yield.
1H NMR (CDCl3) d: 3.36–3.81 (11H, m), 4.23 (1H, d, J = 9.6 Hz),
4.38 (1H, dd, J = 6.0, 9.6 Hz), 4.51 (1H, dd, J = 4.8, 12.4 Hz), 4.58–
4.64 (2H, m), 4.84–4.94 (3H, m), 6.04 (1H, d, J = 12.4 Hz), 6.89–
6.94 (2H, m), 7.14–7.77 (26H, m). MS (FAB) m/z: 761 (M++H), calcd
for C49H48N2O6: 760.
1H NMR (CDCl3) d: 3.48–3.60 (2H, m), 3.73–3.81 (5H, m), 4.10
(2H, s), 4.24 (1H, d, J = 12.7 Hz), 4.37 (1H, d, J = 12.7 Hz), 4.58
(2H, q, J = 16.6 Hz), 4.63 (1H, d, J = 14.2 Hz), 4.86 (1H, d,
J = 14.2 Hz), 4.91 (2H, q, J = 14.2 Hz), 6.32 (1H, d, J = 1.2 Hz), 6.87–
6.90 (2H, m), 7.11–7.43 (26H, m). MS (ESI) m/z: 753 (M++Na), calcd
for C49H46O6: 730.
5.1.26. (1S)-1,5-Anhydro-2,3,4,6-tetra-O-benzyl-1-{3-[(1-meth-
yl-1H-benzimidazole-2-yl)methyl]phenyl}-
D
-glucitol (49)
5.1.31. (1S)-1,5-Anhydro-1-[3-(1-benzofuran-2-ylmethyl)phe-
The title compound was prepared in the same manner as de-
scribed for 34 using 47 instead of 33 in 82% yield.
nyl]-D-glucitol (15)
The title compound was prepared in the same manner as de-
scribed for 8 using 53 instead of 24 in 52% yield.
1H NMR (CDCl3) d: 3.36–3.62 (6H, m), 4.21 (1H, d, J = 9.2 Hz),
4.30 (2H, s), 4.54 (2H, q, J = 10.8 Hz), 4.60 (2H, q, J = 11.2 Hz),
4.83–4.97 (7H, m), 6.84–6.90 (2H, m), 7.12–7.78 (26H, m). MS
(FAB) m/z: 745 (M++H), calcd for C49H48N2O5: 744.
1H NMR (CD3OD) d: 3.35–3.50 (4H, m), 3.69 (1H, dd, J = 4.7,
11.7 Hz), 3.87 (1H, dd, J = 1.4, 11.7 Hz), 4.10 (2H, s), 4.13 (1H, d,
J = 9.3 Hz), 6.44 (1H, s), 7.13–7.18 (2H, m), 7.26–7.36 (4H, m),
7.41 (1H, brs), 7.45–7.47 (1H, m). MS (FAB) m/z: 371 (M++H), calcd
for C21H22O6: 370.
5.1.27. (1S)-1,5-Anhydro-1-{3-[(1-methyl-1H-benzimidazole-2-
yl)methyl]phenyl}-D-glucitol (19)
The title compound was prepared in the same manner as de-
scribed for 8 using 49 instead of 24 in 20% yield.
5.1.32. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-[3-({[tert-
butyl(diphenyl)silyl]oxy}methyl)phenyl]-D-glucitol (54)
1H NMR (CD3OD) d: 3.29–3.50 (4H, m), 3.64–3.70 (1H, m), 3.70
(3H, s), 3.86 (1H, dd J = 4.8, 9.4 Hz), 4.09 (1H, d, J = 9.4 Hz), 4.35
(2H, s), 7.18 (1H, d, J = 7.4 Hz), 7.21–7.37 (5H, m), 7.43 (1H, dd,
J = 1.8, 6.8 Hz), 7.60 (1H, dd, J = 2.4, 6.8 Hz). MS (FAB) m/z: 385
(M++H), calcd for C21H24N2O5: 384.
To a solution of 41 (5.93 g, 6.82 mmol) in MeOH-THF (1:1;
90 mL) was added Pd (10 wt% on carbon) (500 mg) and the mixture
was stirred at rt under H2 atmosphere for 1 day. The reaction mix-
ture was filtered through celite and washed with MeOH. The fil-
trate was evaporated in vacuo, then dried in vacuo. To a solution
of the resulting residue in pyridine (40 mL) was added acetic anhy-
dride (2.68 mL, 28.4 mmol) and 4-dimethylaminopyridine (cata-
lytic amount). The mixture was stirred at rt for 1 day, then
MeOH was added to the reaction mixture. The reaction mixture
was evaporated in vacuo. The resulting residue was dissolved in
EtOAc and washed with H2O. The organic layer was dried over
MgSO4, filtered and evaporated in vacuo and then dried in vacuo
to give the titled compound (54) (4.48 g, 98%) as a colorless oil.
1H NMR (CDCl3) d: 1.10 (9H, s), 1.79, 2.01, 2.06, 2.07 (each 3H,
each s), 3.84 (1H, ddd, J = 2.9, 6.1, 12.9 Hz), 4.15(1H, dd, J = 2.9,
16.1 Hz), 4.28 (1H, dd, J = 6.1, 16.1 Hz), 4.39 (1H, d, J = 12.4 Hz),
4.76 (2H, s), 5.11 (1H, t. J = 12.4 Hz), 5.23 (1H, t, J = 12.4 Hz), 5.34
(1H, t, J = 12.4 Hz), 7.30–7.47 (10H, m), 7.65–7.72(4H, m). MS
(FAB) m/z: 677 (M++H), calcd for C37H44O10Si: 676.
5.1.28. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-
phenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (52)
To a cold (À78 °C) solution of benzothiophene (50) (818 mg,
6.09 mmol) in THF (16 mL) was added n-BuLi (1.60 M in hexane;
3.90 mL, 6.09 mmol) and the mixture was stirred at À78 °C for
1 h. To the reaction mixture was added a solution of 43 (2.55 g,
4.06 mmol) in THF (45 mL) and the mixture was stirred at À78 °C
for 3 h. To the reaction mixture was added H2O and EtOAc, then
the organic layer was separated and washed with brine, dried over
MgSO4, filtered and evaporated in vacuo. The resulting residue was
purified by column chromatography on silica gel (EtOAc–hexane)
to give alcohol (2.48 g, 80%) as a yellow foam. To a solution of this
alcohol (2.47 g, 3.63 mmol) in CH2Cl2 (45 mL) was added Et3SiH
(1.16 mL, 7.26 mmol) and BF3ÁOEt2 (567 mg, 3.99 mmol) and the
mixture was stirred at 0 °C for 4 h. To the reaction mixture was
added saturated aqueous sodium bicarbonate solution and the or-
ganic layer was separated, dried over MgSO4, filtered and evapo-
rated in vacuo. The resulting residue was purified by column
5.1.33. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-[3-(hydroxy-
methyl)phenyl]-D-glucitol (55)
The title compound was prepared in the same manner as de-
scribed for 42 using 54 instead of 41 in 44% yield.

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3275
1H NMR (CDCl3) d: 1.81, 2.00, 2.06, 2.09 (each 3H, each s), 3.84
(1H, ddd J = 3.2, 6.4, 13.2 Hz), 4.14(1H, dd, J = 3.2, 16.6 Hz), 4.30
(1H, dd, J = 6.4, 16.6 Hz), 4.41 (1H, d, J = 13.2 Hz), 4.69 (2H, s),
5.14 (1H, t, J = 13.2 Hz), 5.23 (1H, t, J = 13.2 Hz), 5.34 (1H, t,
J = 13.2 Hz), 7.22–7.35 (3H, m), 7.37 (1H, brs). MS (FAB) m/z: 439
(M++H), calcd for C21H26O10: 438.
7.32 (4H, m), 7.43 (1H, d, J = 7.6 Hz). MS (FAB) m/z: 384 (M++H),
calcd for C22H25NO5: 383.
5.1.37. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-[3-(pyrazin-2-
ylmethyl)phenyl]-D-glucitol (59)
To a suspension of zinc (157 mg, 2.39 mmol) in THF (3.0 mL) was
added 1,2-dibromoethane (1 drop) and the mixture was refluxed for
5 min under Ar atmosphere, then the mixture was cooled down to rt
and chlorotrimethylsilane (1 drop) was added to the mixture. The
mixture was stirred at rt for 15 min under Ar atmosphere. To the
reaction mixture was added a solution of 56 (300 mg, 0.60 mmol)
in THF (3.0 mL) and the mixture was refluxed for 1 h under Ar atmo-
sphere. Then 2-chloropyrazine (68 mg, 0.60 mmol) and tetrakis(tri-
phenylphosphine)palladium (0) (69 mg, 0.24 mmol) was added to
the mixture and the mixture was refluxed for 2 h under Ar atmo-
sphere. The reaction mixture was cooled down to rt, then filtered.
The filtrate was evaporated in vacuo and the resulting residue was
purified by column chromatography on silica gel (EtOAc–hexane)
to give the title compound (59) (223 mg, 75%) as a colorless oil.
1H NMR (CDCl3) d: 1.75, 1.99, 2.06, 2.08 (each 3H, each s), 3.82
(1H, ddd, J = 2.4, 4.8, 9.6 Hz), 4.11–4.14 (1H, m), 4.17 (2H, s), 4.27
(1H, dd, J = 4.8, 12.4 Hz), 4.37 (1H, d, J = 9.6 Hz), 5.11 (1H, t,
J = 9.6 Hz), 5.22 (1H, t, J = 9.6 Hz), 5.31 (1H, t, J = 9.6 Hz), 7.21–
7.32 (4H, m), 8.43 (2H, m), 8.53 (1H, s). MS (ESI) m/z: 501
(M++H), calcd for C25H28N2O9: 500.
5.1.34. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-[3-(bromo-
methyl)phenyl]-D-glucitol (56)
To a cold (0 °C) solution of 55 (1.29 g, 2.94 mmol) in CH2Cl2
(40 mL) was added triphenylphosphine (926 mg, 3.53 mmol) and
carbontetrabromide (1.17 g, 3.53 mmol) and the mixture was stir-
red at rt for 30 min. To the reaction mixture was added saturated
aqueous sodium bicarbonate solution and the organic layer was
separated, dried over MgSO4, filtered and evaporated in vacuo.
The resulting residue was purified by column chromatography on
silica gel (EtOAc–hexane) to give the title compound (56) (1.04 g,
71%) as a white solid.
1H NMR (CDCl3) d: 1.84, 2.00, 2.06, 2.10 (each 3H, each s), 3.85
(1H, ddd, J = 3.2, 6.6, 13.2 Hz), 4.17 (1H, dd, J = 3.2, 16.6 Hz), 4.30
(1H, dd, J = 6.4, 16.6 Hz), 4.41 (1H, d, J = 12.9 Hz), 4.48 (2H, s),
5.10 (1H, t, J = 12.9 Hz), 5.23 (1H, t, J = 12.9 Hz), 5.34 (1H, t,
J = 12.9 Hz), 7.30–7.37 (4H, m). MS (FAB) m/z: 502 (M++H), calcd
for C21H25BrO9: 501.
5.1.35. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-{3-[(1-methyl
-1H-indol-2-yl)methyl]phenyl}-
D
-glucitol (58)
5.1.38. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-[3-(1,3-benzo-
To a cold (0 °C) solution of 1-methyl-1H-indol (57) (3.32 g,
25.31 mmol) in THF (40 mL) was added n-BuLi (1.60 M in hexane;
16.1 mL, 25.3 mmol) and the mixture was stirred at 0 °C for 1 h. To
the reaction mixture was added a solution of tributyl(chloro)stann-
ane (7.42 g, 22.78 mmol) in THF (10 mL) and the mixture was stir-
red at rt for 1.5 h. To the reaction mixture was added brine and
EtOAc, then the organic layer was separated and dried over MgSO4,
filtered and evaporated in vacuo to give a orange syrup (10.2 g,
96%). To a solution of this syrup (546 mg, 1.3 mmol) and 56
(501 mg, 1.0 mmol) in dioxane (10 mL) was added tris(dibenzyli-
deneacetone)palladium (0) (92 mg, 0.1 mmol), dicyclohexylphos-
phinobiphenyl (88 mg, 0.25 mmol), potassium fluoride (174 mg,
3.0 mmol) and cesium carbonate (652 mg, 2.0 mmol). The mixture
was stirred at 60 °C under Ar atmosphere overnight. The reaction
mixture was cooled down to rt, then filtered through celite and
washed with dioxane. The filtrate was evaporated in vacuo and
the resulting residue was purified by column chromatography on
silica gel (EtOAc–hexane) to give the title compound (58)
(280 mg, 51%) as a light orange foam.
thiazol-2-ylmethyl)phenyl]-D-glucitol (60)
The title compound was prepared in the same manner as de-
scribed for 59 using 2-methylthiobenzothiazole instead of 2-chlo-
ropyrazine in 47% yield.
1H NMR (CDCl3) d: 1.77, 1.96, 2.04, 2.09 (each 3H, each s), 3.78
(1H, ddd, J = 2.1, 4.2, 9.4 Hz), 4.08 (1H, dd, J = 2.1, 11.8 Hz), 4.22
(2H, s), 4.24 (1H, dd, J = 4.2, 11.8 Hz), 4.34 (1H, d, J = 9.8 Hz), 5.08
(1H, t, J = 9.8 Hz), 5.16 (1H, t, J = 9.8 Hz), 5.29 (1H, t, J = 9.8 Hz),
7.26–7.38 (4H, m), 7.67–7.84 (4H, m). MS (FAB) m/z: 556 (M++H),
calcd for C28H29NO9S: 555.
5.1.39. (1S)-2,3,4,6-Tetra-O-acetyl-1,5-anhydro-1-[3-(1,3-benzo-
xazol-2-ylmethyl)phenyl]-D-glucitol (61)
The title compound was prepared in the same manner as de-
scribed for 59 using 2-chlorobenzoxazole instead of 2-chloropyra-
zine in 31% yield.
1H NMR (CDCl3) d: 1.71, 1.99, 2.06, 2.11 (each 3H, each s), 3.80–
4.16 (2H, m), 4.25 (2H, s), 4.27 (1H, dd, J = 5.2, 12.8 Hz), 4.39 (1H, d,
J = 9.6 Hz), 5.10 (1H, t, J = 9.6 Hz), 5.22 (1H, t, J = 9.6 Hz), 5.31 (1H, t,
J = 9.6 Hz), 7.28–7.68 (8H, m). MS (ESI) m/z: 540 (M++H), calcd for
1H NMR (CDCl3) d: 1.68, 1.98, 2.05, 2.06 (each 3H, each s), 3.54
(3H, s), 3.81 (1H, ddd, J = 2.0, 4.6, 9.6 Hz), 4.11–4.19 (3H, m), 4.28
(1H, dd, J = 4.6, 12.4 Hz), 4.35 (1H, d, J = 10.0 Hz), 5.10 (1H, t,
J = 10.0 Hz), 5.22 (1H, t, J = 10.0 Hz), 5.30 (1H, t, J = 10.0 Hz), 6.24
(1H, s), 7.06–7.20 (4H, m), 7.21–7.31 (3H, m), 7.54 (1H, d,
J = 12.0 Hz). MS (FAB) m/z: 552 (M++H), calcd for C30H33NO9: 551.
C28H29NO10: 539.
5.1.40. (1S)-1,5-Anhydro-1-[3-(pyrazin-2-ylmethyl)phenyl]-D-
glucitol (13)
The title compound was prepared in the same manner as de-
scribed for 16 using 59 instead of 58 in 32% yield.
5.1.36. (1S)-1,5-Anhydro-1-{3-[(1-methyl-1H-indol-2-yl)meth-
yl]phenyl}-D-glucitol (16)
1H NMR (CD3OD) d: 3.36–3.56 (5H, m), 3.77 (1H, dd, J = 5.2,
12.0 Hz), 4.16 (1H, d, J = 9.6 Hz), 4.20 (2H, s), 7.19–7.37 (4H, m),
8.42 (1H, d, J = 2.8 Hz), 8.49 (2H, m). MS (ESI) m/z: 332 (M+), calcd
for C17H20N2O5: 332.
To a solution of 58 (270 mg, 0.49 mmol) in THF–MeOH (1:1;
20 mL) was added sodium methoxide (catalytic amount) and the
mixture was stirred at rt for 1 h. To the reaction mixture was added
ion exchange resign (Dowex 50 W-x8, H+ form) and filtered. The
filtrate was evaporated in vacuo and the resulting residue was
purified by column chromatography on silica gel (MeOH-CHCl3)
to give the title compound (16) (118 mg, 61%) as a white foam.
1H NMR (CD3OD) d: 3.32–3.48 (4H, m), 3.57 (3H, s), 3.67 (1H, dd,
J = 5.4, 11.7 Hz), 3.86 (1H, dd, J = 1.4, 11.7 Hz), 4.09 (1H, d,
J = 9.3 Hz), 4.17 (2H, s), 6.22 (1H, s), 6.97 (1H, dt, J = 1.0, 7.6 Hz),
7.08 (1H, dt, J = 1.0, 7.6 Hz), 7.14 (1H, dt, J = 2.1, 6.9 Hz), 7.24–
5.1.41. (1S)-1,5-Anhydro-1-[3-(1,3-benzothiazol-2-ylmethyl)-
phenyl]-D-glucitol (17)
The title compound was prepared in the same manner as de-
scribed for 16 using 60 instead of 58 in 69% yield.
1H NMR (CD3OD) d: 3.35–3.50 (4H, m), 3.67–3.72 (1H, m), 3.88
(1H, dd J = 1.9, 12.2 Hz), 4.14 (1H, d, J = 9.8 Hz), 4.49 (2H, s), 7.32–
7.43 (4H, m), 7.48–7.53 (2H, m), 7.91–7.93 (2H, m). MS (FAB) m/z:
388 (M++H), calcd for C20H21NO5S: 387.

3276
M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
5.1.42. (1S)-1,5-Anhydro-1-[3-(1,3-benzoxazol-2-ylmethyl)phe-
nyl]- -glucitol (18)
5.1.47. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
(methoxymethoxy)phenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol
D
The title compound was prepared in the same manner as de-
scribed for 16 using 61 instead of 58 in 72% yield.
(68)
The title compound was prepared in the same manner as de-
scribed for 24 using 66 instead of 22 in 57% yield.
1H NMR (CD3OD) d: 3.41–3.48 (2H, m), 3.54–3.58 (2H, m), 3.77
(1H, dd, J = 5.3, 12.0 Hz), 3.86–3.89 (1H, m), 4.17 (1H, d, J = 9.6 Hz),
4.28 (2H, s), 7.31–7.38 (5H, m), 7.44 (1H, s), 7.48–7.62 (2H, m). MS
(ESI) m/z: 372 (M++H), calcd for C20H21NO10: 371.
1H NMR (CDCl3) d: 3.35 (3H, s), 3.59–3.61 (1H, m), 3.72–3.82
(4H, m), 3.93 (1H, d, J = 9.7 Hz), 4.17 (2H, q J = 17.0 Hz), 4.43 (1H,
d, J = 10.7 Hz), 4.55 (2H, q, J = 12.2 Hz), 4.75 (2H, q, J = 10.7 Hz),
4.92 (2H, q, J = 10.7 Hz), 5.04 (2H, q, J = 12.2 Hz), 5.0 (2H, q,
J = 7.0 Hz), 6.85–6.88 (2H, m), 6.96 (1H, s), 7.09–7.31 (22H, m),
7.42 (1H, d, J = 2.0 Hz), 7.56 (1H, d, J = 7.6 Hz), 7.55 (1H, d,
J = 7.6 Hz). MS (ESI) m/z: 830 (M++Na), calcd for C51H50O7S: 807.
5.1.43. 3-bromo-4-(methoxymethoxy)benzaldehyde (64)
To a cold (0 °C) solution of 3-bromo-4-hydroxybenzaldehyde
(62) (10.5 g, 52.3 mmol) in DMF (120 mL) was added sodium hy-
dride (60% in mineral oil) (2.14 g, 55.4 mmol) and the mixture
was stirred at 0 °C for 15 min. To the reaction mixture was added
chloromethylmethylether (4.73 mL, 62.9 mmol) and the mixture
was stirred at rt overnight. The reaction mixture was diluted with
EtOAc and washed with H2O. The organic layer was dried over
MgSO4, filtered and evaporated in vacuo. The resulting residue
was purified by column chromatography on silica gel (EtOAc–hex-
ane) to give the title compound (64) (11.7 g, 91%) as a colorless oil.
1H NMR (CDCl3) d: 3.53 (3H, s), 5.35 (2H, s), 7.27 (1H, d,
J = 8.4 Hz), 7.79 (1H, dd, J = 2.0, 8.4 Hz), 8.09 (1H, d, J = 3.4 Hz),
9.86 (1H, s). MS (FAB) m/z: 245 (M+), calcd for C9H9BrO3: 245.
5.1.48. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
(methoxymethoxy)phenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol
(69)
The title compound was prepared in the same manner as de-
scribed for 24 using 67 instead of 22 in 14% yield.
1H NMR (CDCl3) d: 3.43 (3H, s), 3.45–3.60 (1H, m), 3.72–4.01
(5H, m), 4.15–4.38 (4H, m), 4.51–4.70 (4H,m), 4.83–4.94 (3H, m),
5.23 (2H, s), 6.85–7.40 (26H, m), 7.54 (1H, d, J = 7.6 Hz), 7.64 (1H,
d, J = 7.6 Hz). MS (ESI) m/z: 830 (M++Na), calcd for C51H50O7S: 807.
5.1.49. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
5.1.44. 3-bromo-5-(methoxymethoxy)benzaldehyde (65)
The title compound was prepared in the same manner as de-
scribed for 64 using 3-bromo-5-hydroxybenzaldehyde (63) instead
of 62 in 98% yield.
hydroxyphenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (70)
To a cold (0 °C) solution of 68 (21.7 g, 26.9 mmol) in EtOAc
(135 mL) was added 4 M HCl solution in EtOAc (135 mL, 540 mmol)
and the mixture was stirred at rt overnight. The reaction mixture
was evaporated in vacuo and the resulting residue was purified
by column chromatography on silica gel (EtOAc–hexane) to give
the title compound (70) (18.6 g, 91%) as a pale yellow oil.
1H NMR (CDCl3) d: 3.54–3.58 (1H, m), 3.67–3.77 (4H, m), 3.83–
3.97 (2H, m), 4.05–4.17 (2H, m), 4.37–4.48 (3H, m), 4.52–4.62 (2H,
m), 4.83–4.95 (3H, m), 6.90–7.70 (28H, m). MS (FAB) m/z: 785
(M++Na), calcd for C49H46O6S: 762.
1H NMR (CDCl3) d: 3.52 (3H, s), 5.29 (2H, s), 7.15 (1H, d,
J = 11.9 Hz), 7.61 (1H, dd, J = 3.4, 8.4 Hz), 7.94 (1H, d, J = 3.4 Hz),
10.42 (1H, s). MS (FAB) m/z: 245 (M+), calcd for C9H9BrO3: 245.
5.1.45. 2-[3-bromo-4-(methoxymethoxy)benzyl]-1-benzothio-
phene (66)
To a cold (À78 °C) solution of 50 (16.6 g, 124 mmol) in THF
(200 mL) was added n-BuLi (1.60 M in hexane; 78.5 mL, 124 mmol)
and the mixture was stirred at À78 °C for 1.5 h. To the reaction
mixture was added a solution of 64 (29.0 g, 118 mmol) in THF
(300 mL) and the mixture was stirred at À78 °C for 2 h. To the reac-
tion mixture was added H2O and Et2O and the organic layer was
separated, dried over MgSO4, filtered and evaporated in vacuo.
The resulting residue was purified by column chromatography on
silica gel (EtOAc–hexane) to give alcohol as a pale yellow oil. To
a cold (À20 °C) solution of this oil (43.3 g, 114 mmol) in CH2Cl2
(800 mL) was added Et3SiH (36.5 mL, 229 mmol) and BF3ÁOEt2
(15.2 mL, 120 mmol) and the mixture was stirred at À20 °C for
30 min. To the reaction mixture was added saturated aqueous so-
dium bicarbonate solution and the organic layer was separated,
dried over MgSO4, filtered and evaporated in vacuo. The resulting
residue was purified by column chromatography on silica gel
(EtOAc–hexane) to give the title compound (66) (35.6 g, 86%) as
a pale yellow oil.
5.1.50. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
hydroxyphenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (71)
The title compound was prepared in the same manner as de-
scribed for 70 using 69 instead of 68 in 82% yield.
1H NMR (CDCl3) d: 3.44–3.65 (2H, m), 3.70–3.92 (4H, m), 4.13–
4.27 (3H, m), 4.37 (1H, d, J = 13.7 Hz), 4.50–4.67 (4H, m), 4.80–4.96
(4H, m), 6.75–7.05 (3H, m), 7.08–7.35 (23H, m), 7.56 (1H, d,
J = 9.0 Hz), 7.67 (1H, d, J = 10.8 Hz). MS (FAB) m/z: 761 (M+-H),
calcd for C49H46O6S: 762.
5.1.51. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
hydroxyphenyl]-D-glucitol (14b)
The title compound was prepared in the same manner as de-
scribed for 8 using 70 instead of 24 in 45% yield.
1H NMR (CD3OD) d: 3.39–3.43 (2H, m), 3.44–3.58 (2H, m), 3.67–
3.73 (2H, m), 3.86 (1H, dd, J = 1.7, 11.8 Hz), 4.14 (2H, s), 4.57 (1H, d,
J = 9.3 Hz), 6.78 (1H, d, J = 8.3 Hz), 7.02 (1H, s), 7.08 (1H, dd, J = 2.0,
7.8 Hz), 7.22–7.24 (1H, m), 7.31 (1H, d, J = 7.8 Hz), 7.64 (1H, d,
J = 7.3 Hz), 7.71 (1H, d, J = 7.6 Hz). MS (FAB) m/z: 401 (M+-H), calcd
for C21H22O6S: 402.
1H NMR (CDCl3) d: 3.51 (3H, s), 4.14 (2H, s), 5.22 (2H, s), 7.00
(1H, s), 7.09 (1H, d, J = 4.8 Hz), 7.16 (1H, dd, J = 2.0, 8.4 Hz), 7.22–
7.33 (2H, m), 7.47 (1H, d, J = 2.0 Hz), 7.66 (1H, d, J = 7.2 Hz), 7.73
(1H, d, J = 12.0 Hz). MS (FAB) m/z: 364 (M++H), calcd for
C17H15BrO2S: 363.
5.1.52. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
5.1.46. 2-[3-bromo-5-(methoxymethoxy)benzyl]-1-benzothio-
phene (67)
hydroxyphenyl]-D-glucitol (14f)
The title compound was prepared in the same manner as de-
scribed for 8 using 71 instead of 24 in 73% yield.
The title compound was prepared in the same manner as de-
scribed for 66 using 65 instead of 64 in 76% yield.
1H NMR (CDCl3) d: 3.38 (3H, s), 4.22 (2H, s), 5.16 (2H, q,
J = 9.0 Hz), 6.93 (1H, d, J = 11.7 Hz), 7.01 (1H, s), 7.16–7.30 (4H,
m), 7.59 (1H, dd, J = 2.2, 8.8 Hz), 7.70 (1H, dd, J = 2.9, 13.0 Hz).
MS (FAB) m/z: 364 (M++H), calcd for C17H15BrO2S: 363
1H NMR (CD3OD) d: 3.33–3.46 (4H, m), 3.62–3.68 (1H, m), 3.84
(1H, dd, J = 1.7, 11.8 Hz), 4.02 (1H, d, J = 9.3 Hz), 4.18 (2H, q,
J = 15.7 Hz), 6.80 (1H, d, J = 8.3 Hz), 7.03 (1H, d, J = 1.0 Hz), 7.11–
7.27 (4H, m), 7.62 (1H, d, J = 7.0 Hz), 7.69 (1H, d, J = 7.0 Hz). MS
(FAB) m/z: 401 (M+-H), calcd for C21H22O6S: 402.

M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
3277
5.1.53. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
methoxyphenyl]-2,3,4,6-tetra-O-benzyl- -glucitol (72)
5.1.59. 2-(5-bromo-2-fluorobenzyl)-1-benzothiophene (76)
D
The title compound was prepared in the same manner as de-
scribed for 66 using 5-bromo-2-fluorobenzaldehyde instead of 64
in 64% yield.
To a solution of 70 (763 mg, 1.00 mmol) in DMF (10 mL) was
added potassium carbonate (207 mg, 1.50 mmol) and iodomethane
(0.1 mL, 1.5 mmol). The mixture was stirred at rt overnight. The
reaction mixture was diluted with EtOAc and washed with H2O,
brine. The organic layer was dried over MgSO4, filtered and evapo-
rated in vacuo. The resulting residue was purified by column chro-
matography on silica gel (EtOAc–hexane) to give the title
compound (72) (736 mg, 95%) as a colorless oil.
1H NMR (CDCl3) d: 4.20 (2H, s), 6.95 (1H, t, J = 9.2 Hz), 7.02 (1H,
s), 7.25–7.40 (4H, m), 7.67 (1H, d, J = 7.3 Hz), 7.74 (1H, d, J = 7.3 Hz).
MS (FAB) m/z: 322 (M++H), calcd for C10H15BrFS: 321.
5.1.60. 2-(5-bromo-2-chlorobenzyl)-1-benzothiophene (77)
The title compound was prepared in the same manner as de-
scribed for 66 using 5-bromo-2-chlorobenzaldehyde instead of
64 in 46% yield.
1H NMR (CDCl3) d: 3.58–3.62 (1H, m), 3.71–3.82 (9H, m), 3.92
(1H, d, J = 10.8 Hz), 4.15–4.19 (2H, m), 4.40 (1H, d, J = 10.8 Hz),
4.52 (1H, d, J = 12.0 Hz), 4.61–4.65 (2H, m), 4.84–4.88 (2H, m),
4.94 (1H, d, J = 10.8 Hz), 6.84–6.89 (3H, m), 6.95 (1H, s), 7.11–
7.31 (21H, m), 7.42 (1H, d, J = 2.0 Hz), 7.56 (1H, d, J = 7.0 Hz),
7.65 (1H, d, J = 7.0 Hz). MS (ESI) m/z: 799 (M++Na), calcd for
C50H48O6S: 776.
1H NMR (CDCl3) d: 4.23 (2H, s), 7.14 (1H, s), 7.22 (1H, t,
J = 9.6 Hz), 7.27–7.41 (4H, m), 7.69 (1H, d, J = 7.2 Hz), 7.76 (1H,
d, J = 7.2 Hz). MS (FAB) m/z: 338 (M++H), calcd for C10H15BrClS:
337.
5.1.61. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
fluorophenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (78)
5.1.54. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
methoxyphenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (73)
The title compound was prepared in the same manner as de-
scribed for 24 using 74 instead of 22 in 22% yield.
The title compound was prepared in the same manner as de-
scribed for 72 using 71 instead of 70 in 92% yield.
1H NMR (CDCl3) d: 3.60–3.68 (1H, m), 3.73–3.85 (3H, m), 3.92–
4.23 (3H, m), 4.42–4.78 (8H, m), 4.83–4.95 (2H, m), 6.85–6.98 (3H,
m), 7.05–7.39 (23H, m), 7.54–7.61 (1H, m), 7.62–7.69 (1H, m). MS
(ESI) m/z: 787 (M++Na), calcd for C49H45FO5S: 764.
1H NMR (CDCl3) d: 3.47–3.78 (1H, m), 3.87 (3H, s), 4.13–4.29
(6H, m), 4.33 (1H, d, J = 10.5 Hz), 4.49–4.75 (5H, m), 4.84–4.94
(4H, m), 6.86–6.95 (3H, m), 7.06–7.37 (23H, m), 7.58 (1H, d,
J = 6.8 Hz), 7.66 (1H, d, J = 7.7 Hz). MS (FAB) m/z: 775 (M+-H), calcd
for C50H48O6S: 776.
5.1.62. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
chlorophenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (79)
The title compound was prepared in the same manner as de-
scribed for 24 using 75 instead of 22 in 34% yield.
5.1.55. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
methoxyphenyl]-D-glucitol (14c)
The title compound was prepared in the same manner as de-
scribed for 8 using 72 instead of 24 in 29% yield.
1H NMR (CDCl3) d: 3.61–3.66 (2H, m), 3.71–3.88 (3H, m), 3.95
(1H, d, J = 10.2 Hz), 4.18 (2H, s), 4.37 (1H, d, J = 10.2 Hz), 4.51–
4.65 (4H, m), 4.83–4.94 (4H, m), 6.93–6.96 (3H, m), 7.13–7.31
(21H, m), 7.35 (1H, d, J = 4.8 Hz), 7.48 (1H, d, J = 2.4 Hz), 7.58 (1H,
d, J = 7.2 Hz), 7.67 (1H, d, J = 7.2 Hz). MS (ESI) m/z: 803 (M++Na),
calcd for C49H45ClO5S: 780.
1H NMR (CD3OD) d: 3.36–3.39 (2H, m), 3.46–3.54 (2H, m), 3.63–
3.68 (1H, m), 3.81–3.86 (4H, m), 4.12 (2H, s), 4.69 (1H, d,
J = 9.2 Hz), 6.94 (1H, d, J = 8.3 Hz), 7.04 (1H, s), 7.20–7.28 (3H, m),
7.39 (1H, d, J = 2.5 Hz), 7.64 (1H, d, J = 7.6 Hz), 7.71 (1H, d,
J = 7.6 Hz). MS (FAB) m/z: 417 (M++H), calcd for C22H24O6S: 416.
5.1.63. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
fluorophenyl]-2,3,4,6-tetra-O-benzyl-D-glucitol (80)
5.1.56. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
methoxyphenyl]-D-glucitol (14g)
The title compound was prepared in the same manner as de-
scribed for 24 using 76 instead of 22 in 61% yield.
The title compound was prepared in the same manner as de-
scribed for 8 using 73 instead of 24 in 27% yield.
1H NMR (CDCl3) d: 3.42–3.48 (1H, m), 3.55–3.58 (1H, m), 3.72–
3.78 (3H, m), 3.83 (1H, d, J = 10.7 Hz), 4.14–4.30 (3H, m), 4.39 (1H,
d, J = 10.7 Hz), 4.51–4.67 (3H, m), 4.83–4.94 (4H, m), 6.86–6.90
(1H, m), 6.98 (1H, brs), 7.06–7.37 (24H, m), 7.57–7.60 (1H, m),
7.66–7.69 (1H, m). MS (ESI) m/z: 787 (M++Na), calcd for
1H NMR (CD3OD) d: 3.34–3.45 (4H, m), 3.65–3.69 (2H, m), 3.85
(3H, s), 4.06 (1H, d, J = 9.3 Hz), 4.20 (2H, d, J = 7.3 Hz), 6.96 (1H, d,
J = 7.8 Hz), 7.00 (1H, d, J = 1.0 Hz), 7.18–7.31 (4H, m), 7.61 (1H, d,
J = 8.3 Hz), 7.69 (1H, d, J = 8.3 Hz). MS (FAB) m/z: 415 (M+-H), calcd
for C22H24O6S: 416.
C49H45FO5S: 764.
5.1.57. 2-(3-bromo-4-fluorobenzyl)-1-benzothiophene (74)
The title compound was prepared in the same manner as de-
scribed for 66 using 3-bromo-4-fluorobenzaldehyde instead of 64
in 36% yield.
5.1.64. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
chlorophenyl]-2,3,4,6-tetra-O-benzyl- -glucitol (81)
The title compound was prepared in the same manner as de-
scribed for 24 using 77 instead of 22 in 14% yield.
D
1H NMR (CDCl3) d: 4.16 (2H, s), 7.11 (1H, t, J = 8.8 Hz), 7.14 (1H,
s), 7.30 (1H, dd, J = 1.2, 6.8 Hz), 7.33 (1H, dd, J = 1.6, 7.2 Hz), 7.35–
7.40 (1H, m), 7.69–7.71 (2H, m), 7.78 (1H, d, J = 7.3 Hz). MS (FAB)
m/z: 322 (M++H), calcd for C10H15BrFS: 321.
1H NMR (CDCl3) d: 3.42–3.48 (1H, m), 3.50–3.64 (1H, m), 3.72–
3.78 (4H, m), 3.88 (1H, d, J = 9.6 Hz), 4.19 (1H, d, J = 9.6 Hz), 4.22–
4.34 (2H, m), 4.35–4.45 (1H, m), 4.50–4.65 (2H, m), 4.85–4.90 (4H,
m), 6.90 (2H, d, J = 7.6 Hz), 6.94 (1H, s), 7.10–7.42 (23H, m), 7.56
(1H, d, J = 7.2 Hz), 7.65 (1H, d, J = 7.2 Hz). MS (ESI) m/z: 803
(M++Na), calcd for C49H45ClO5S: 780.
5.1.58. 2-(3-bromo-4-chlorobenzyl)-1-benzothiophene (75)
The title compound was prepared in the same manner as de-
scribed for 66 using 3-bromo-4-chlorobenzaldehyde instead of
64 in 48% yield.
5.1.65. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
fluorophenyl]-D-glucitol (14d)
1H NMR (CDCl3) d: 4.19 (2H, s), 7.11 (1H, s), 7.17 (1H, t,
J = 9.2 Hz), 7.23–7.38 (4H, m), 7.73 (1H, d, J = 7.4 Hz), 7.82 (1H,
d, J = 7.4 Hz). MS (FAB) m/z: 338 (M++H), calcd for C10H15BrClS:
337.
The title compound was prepared in the same manner as de-
scribed for 8 using 78 instead of 24 in 24% yield.
1H NMR (CD3OD) d: 3.34–3.52 (4H, m), 3.66–3.72 (1H, m), 3.87
(1H, d, J = 11.2 Hz), 4.22 (2H, s), 4.52 (1H, d, J = 9.3 Hz), 7.02 (1H.

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M. Imamura et al. / Bioorg. Med. Chem. 20 (2012) 3263–3279
dd, J = 8.3, 9.8 Hz), 7.06 (1H, s), 7.18–7.32 (3H, m), 7.49 (1H, dd,
J = 2.2, 8.8 Hz), 7.66 (1H, d, J = 7.6 Hz), 7.72 (1H, d, J = 7.6 Hz). MS
(FAB) m/z: 405 (M++H), calcd for C21H21FO5S: 404.
75 ll MicroScint MS-40 (Packard Instrument Co., Meriden, CT,
USA) and radioactivity was measured using a Top Count Micro-
plate Scintillation Counter (Packard Instrument Co., Meriden, CT,
USA).
5.1.66. (1S)-1,5-Anhydro-1-[5-(1-benzothiophen-2-ylmethyl)-2-
chlorophenyl]-
D-glucitol (14e)
5.2.2. In vivo pharmacology
The title compound was prepared in the same manner as de-
scribed for 8 using 79 instead of 24 in 86% yield.
5.2.2.1. Animals.
Male Sprague–Dawley rats were purchased
from Charles River Laboratories Japan (Kanagawa, Japan) at age
5–7 weeks. STZ was dissolved in 50 mM citric acid buffer before
intravenous administration at 50 mg/kg. Blood glucose levels were
measured in the diabetic rats 1 week later, after which the rats
were grouped such that the blood glucose levels were similar in
each group. Male Institute of Cancer Research normal and KK-Ay
type 2 diabetic mice, which exhibit hyperglycemia, insulin resis-
tance, hyperinsulinemia, hyperlipidemia, and obesity, were pur-
chased from Japan SLC, Inc. (Shizuoka, Japan) and CLEA Japan
(Kanagawa, Japan), respectively, at the age of 5–6 weeks. The dia-
betic mice were also grouped such that each group had similar
blood glucose levels. All animals were housed under conventional
conditions with controlled temperature, humidity, and light (12-h
light–dark cycle) and were provided with a standard commercial
diet and water (ad libitum). Animals were handled and cared for
in accordance with the Guide for the Care and Use of Laboratory Ani-
mals, and all procedures were approved by the Animal Ethical
Committee of Astellas Pharma Inc.
1H NMR (CD3OD) d: 3.41–3.44 (2H, m), 3.49–3.55 (2H, m), 3.66–
3.70 (1H, m), 3.86 (1H, d, J = 10.4 Hz), 4.24 (2H, s), 4.73 (1H, d,
J = 9.6 Hz), 7.07 (1H, s), 7.21–7.29 (3H, m), 7.34 (1H, d, J = 2.4 Hz),
7.55 (1H, s), 7.66 (1H, d, J = 7.2 Hz), 7.73 (1H, d, J = 7.2 Hz). MS
(FAB) m/z: 419 (M+-H), calcd for C21H21ClO5S: 420.
5.1.67. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
fluorophenyl]-D-glucitol (14h)
The title compound was prepared in the same manner as de-
scribed for 24 using 80 instead of 24 in 64% yield.
1H NMR (CD3OD) d: 3.35–3.49 (4H, m), 3.68 (1H, dd, J = 5.4,
11.7 Hz), 3.87 (1H, dd, J = 1.9, 11.7 Hz), 4.11 (1H, d, J = 9.3 Hz),
4.23 (2H, q, J = 15.6 Hz), 7.05 (1H, s), 7.07 (1H, dd, J = 8.3, 9.8 Hz),
7.21–7.30 (2H, m), 7.35 (1H, ddd, J = 2.2, 4.9, 8.3 Hz), 7.43 (1H,
dd, J = 2.2, 7.6 Hz), 7.66 (1H, d, J = 7.6 Hz), 7.72 (1H, d, J = 7.6 Hz).
13C NMR (DMSO-d6) d: 29.51, 61.34, 70.30, 74.72, 78.33, 80.68,
81.24, 114.62, 121.61, 122.24, 123.06, 123.82, 124.32, 125.49,
128.31, 130.52, 136.83, 138.90, 139.60, 143.81, 159.58. MS (FAB)
m/z: 405 (M++H), calcd for C21H21FO5S: 404. IR
3067, 2973, 2909, 1506, 1084, 1062 cm-1
Anal. Calcd for
21H21FO5S: C, 62.36; H, 5.23; F, 4.70; S, 7.93. Found: C, 62.25; H,
5.47; F, 4.52; S, 7.76.
m
: 3309, 3193,
5.2.2.2. Effect of 14h on urinary glucose excretion in normal
.
mice.
6. 14 h (0.01–10 mg/kg) was administered to non-
C
fasted normal mice, and spontaneously voided urine was collected
for 24 h after administration while the animals were kept in met-
abolic cages. After the urine volume had been measured, the glu-
cose concentration in the urine was measured using the Glucose
CII test reagent (Wako, Osaka, Japan).
5.1.68. (1S)-1,5-Anhydro-1-[3-(1-benzothiophen-2-ylmethyl)-4-
chlorophenyl]- -glucitol (14i)
D
The title compound was prepared in the same manner as de-
scribed for 24 using 81 instead of 24 in 70% yield.
5.2.2.3. Effect of single administration of 14h in diabetic
1H NMR (CD3OD) d: 3.26–3.52 (4H, m), 3.69 (1H, dd, J = 5.4,
11.9 Hz), 3.87 (1H, dd, J = 2.0, 11.9 Hz), 4.12 (1H, d, J = 9.3 Hz),
4.36 (2H, q, J = 15.8 Hz), 7.01 (1H, s), 7.20–7.29 (2H, m), 7.34 (1H,
dd, J = 1.9, 8.3 Hz), 7.40 (1H, d, J = 8.3 Hz), 7.48 (1H, d, J = 1.9 Hz),
7.64 (1H, d, J = 7.8 Hz), 7.73 (1H, d, J = 7.8 Hz). MS (FAB) m/z: 421
(M++H), calcd for C21H21ClO5S: 420.
animals.
To investigate its antihyperglycemic effect, 14h
(0.1–1 mg/kg) was administered to STZ-induced type 1 diabetic
rats and KK-Ay type 2 diabetic mice in the fed condition. Blood
glucose levels were then measured for 8 h under fasting condi-
tions, in order to eliminate the influence of feeding during the
experiment.
5.2. Pharmacology
Acknowledgments
5.2.1. In vitro pharmacology
5.2.1.1. SGLT2 and SGLT1 inhibition assay.
We thank Dr. Susumu Watanuki and Dr. Yasuhiro Yonetoku for
their useful advice. We are also grateful to Dr. Atsuo Tahara, Mr.
Masanori Yokono, Mr. Daisuke Yamajuku, Ms. Rumi Kihara , Ms.
Takako Furukawa and Dr. Fumihiko Ushigome for performing the
biological experiments, and members of the Division of Analytical
Science Laboratories for elemental analysis and spectral
measurements.
Human, rat, and
mouse SGLT2 or SGLT1 full-length complementary deoxyribonu-
cleic acid (cDNA) sequences were cloned and stably transfected
into Chinese hamster ovary (CHO) cells using standard techniques
as described previously (Katsuno et al. 2007). Cells were seeded
into 96-well plates at a density of 3 Â 104 cells/well in Ham’s
F12 medium containing 10% fetal bovine serum (FBS). The cells
were used 1 day after plating. Test compounds were initially dis-
solved in dimethyl sulfoxide (DMSO) and diluted to the desired
concentration with sodium assay buffer (140 mM NaCl, 2 mM
KCl, 1 mM CaCl2, 1 mM MgCl2, 10 mM N-2-hydroxyethylpiper-
azine-N’-2-ethanesulfonic acid [HEPES], 5 mM tris–HCl, pH 7.4).
After the medium was removed, the cells were preincubated in
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