Novel thiophenyl C-aryl glucoside SGLT2 inhibitors as potential antidiabetic agents

Article abstract of DOI:10.1016/j.bmc.2011.08.014

Novel thiophene C-aryl glucoside SGLT2 inhibitors were designed and synthesized. Two different types of thiophene derivatives were readily prepared. Among the compounds tested, ethylphenyl at the distal ring 71p showed the best in vitro inhibitory activit

Full text of DOI:10.1016/j.bmc.2011.08.014

Bioorganic & Medicinal Chemistry 19 (2011) 5813–5832
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Novel thiophenyl C-aryl glucoside SGLT2 inhibitors as potential
antidiabetic agents
Suk Ho Lee a,b, Kwang-Seop Song a, Jong Yup Kim a, Misuk Kang a, Jun Sung Lee a, Seung-Hwan Cho a,
Hyun-Ju Park b, Jeongmin Kim a, Jinhwa Lee a,
⇑
a Research Center, Green Cross Corporation, 303 Bojeong-Dong, Giheung-Gu, Yongin, Gyeonggi-Do 446-770, Republic of Korea
b College of Pharmacy, Sungkyunkwan University, Cheoncheon-Dong, Jangan-Gu, Suwon, Gyeonggi-Do 440-746, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
Novel thiophene C-aryl glucoside SGLT2 inhibitors were designed and synthesized. Two different types of
thiophene derivatives were readily prepared. Among the compounds tested, ethylphenyl at the distal ring
71p showed the best in vitro inhibitory activity in this series to date (IC50 = 4.47 nM) against SGLT2.
Ó 2011 Elsevier Ltd. All rights reserved.
Received 28 June 2011
Revised 8 August 2011
Accepted 9 August 2011
Available online 22 August 2011
Keywords:
SGLT
Dapagliflozin
Thiophene
Glucoside
Diabetes
1. Introduction
and the GI tract represents a major locus of action of SGLT1 in glu-
cose trafficking. Also, SGLT1 is located in the kidney and the heart
Diabetes has become an augmenting concern to the world’s
population. In 2007, approximately 246 million people were influ-
enced by the disease, with an additional 7 million people develop-
ing the disease every year.1 The ADA states, ‘Diabetes mellitus is a
group of metabolic diseases characterized by hyperglycemia
resulting from defects in insulin secretion, insulin action, or both.
The chronic hyperglycemia of diabetes is associated with long-
term damage, dysfunction, and failure of various organs, especially
the eyes, kidneys, nerves, heart, and blood vessels’.2 There are two
identified form of diabetes: Type 1 diabetes is distinguished as an
autoimmune disease involving pancreatic b-cells, while type 2 dia-
betes is associated with b-cell dysfunction3 and is defined by a de-
fect in glucose regulation and metabolism. Type 2 diabetes is the
most dominant disorder of glucose homeostasis, accounting for
nearly 90–95% of all cases of diabetes. While diabetes is often a re-
sult of impaired insulin secretion or action, the actual measure of
diabetes relates to glucose levels.
where its expression regulates cardiac glucose transport.6 SGLT1 is
a high-affinity, low-capacity transporter and therefore accounts for
only a small fraction of renal glucose reabsorption.7 In contrast,
SGLT2 is a low-affinity, high-capacity transporter located exclu-
sively at the apical domain of the epithelial cells in the early prox-
imal convoluted tubule. It is estimated that 90% of renal glucose
reabsorption is facilitated by SGLT2; the remaining 10% is likely
mediated by SGLT1 in the late proximal straight tubule.8 Since
SGLT2 appears to be responsible for the majority of renal glucose
reabsorption based on human mutation studies,9 it has become a
target of therapeutic interest.
Scientists at Bristol-Myers Squibb has identified dapagliflozin
(Fig. 1), a potent, selective SGLT2 inhibitor for the treatment of type
2 diabetes.10–12 At present, dapagliflozin is the most advanced
SGLT2 inhibitor in clinical trials. On the other hand, Mitsubishi
Tanabe, in collaboration with Johnson & Johnson, is developing
canagliflozin 2, another novel C-glucoside-derived SGLT2 inhibi-
tor.13 In addition, Boehringer Ingelheim (BI 10773), Lexicon
(LX4211), Astellas (ASP1941), and Pfizer (PF-04971729) are re-
ported to be in various phase of clinical trials.14 Our efforts on
identifying inhibitors that target SGLT2 have been previously
described.15
Sodium-dependent glucose cotransporters (SGLTs) couple the
transport of glucose against a concentration gradient with the
simultaneous transport of Na+ down a concentration gradient.4
Two important SGLT isoforms have been cloned and identified,
SGLT1 and SGLT2.5 SGLT1 is typically in the GI tract of humans
In the present study, C-glucosides bearing thiophene ring at the
proximal ring were exploited in order to develop novel SGLT2
targeting antidiabetic agents. We envisioned that replacement of
⇑
Corresponding author. Tel.: +82 31 260 9892; fax: +82 31 260 9020.
E-mail address: jinhwalee@greencross.com (J. Lee).
0968-0896/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2011.08.014

5814
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
Cl OEt
Me
O
O
HO
HO
F
S
HO
HO
OH
OH
OH
OH
canagliflozin
dapagliflozin
Cl
OEt
Cl
OEt
O
O
MeS
HO
O
HO
HO
OH
PF-04971729
OH
OH
OH
LX4211
Figure 1. Structures of C-aryl glucoside SGLT2 inhibitors.
the proximal ring of dapagliflozin with a well-known analogy for
phenyl ring would be a worthy approach for modulating physico-
chemical property, possibly to improve biological activity. For this
purpose, structure of dapagliflozin was modified into A bearing
thiophene at the proximal ring as shown in Figure 2. Herein, we re-
port design, synthesis, and biological evaluation of benzylthiophe-
nyl glucoside congeners.
phene-3-carboxylic acid 1 with oxalyl chloride, generated the
desired diarylketone 2 in 98% yield. The reduction of diarylketone
2 by triethylsilane in the presence of boron trifluoride etherate
provided aglycon 3 in 82% yield. 4-((5-Bromo-2-chlorothiophen-
3-yl)methyl)phenol, the key intermediate 4, was generated via
demethylation with BBr3 in quantitative yield. Alkylated aglycons
such as 5 or 6 were generated via alkylation with alkyl halide in
the presence of suitable base such as cesium carbonate or with cor-
responding alcohol with DIAD and PPh3 under Mitsunobu reaction
conditions.
The synthesis of various thienyl iodides was shown in Scheme
2. 5-Bromo-2-methylthiophene-3-carboxylic acid 8 was obtained
in good yield (84%) by bromination at the thiophene ring of 2-
methylthiophene-3-carboxylic acid 7 using bromine generated
from pyridinium tribromide in glacial acetic acid.16 Friedel–Crafts
2. Results and discussion
2.1. Chemistry
The synthesis of various thienyl bromides was shown in Scheme
1. Friedel–Crafts acylation of anisole with 5-bromo-2-chlorothio-
phene-3-carbonyl chloride, formed form 5-bromo-2-chlorothio-
R2
R1
Cl
OEt
S
O
O
HO
HO
HO
OH
dapagliflozin
HO
OH
OH
OH
A
Figure 2. Exploration of C-glucoside bearing thiophene at the proximal ring.
O
O
OH
Cl
Cl
(COCl)2, cat. DMF
CH2Cl2
anisole, AlCl3
CH2Cl2
Et 3SiH, BF3OEt2
CH2Cl2
S
Br
S
Br
O
2
1
O
Cl
S
1-iodopropane, Cs2CO3
acetone
Br
5
OH
O
Cl
BBr3
Cl
S
S
O
CH2Cl2
Br
Cl
Br
S
4
3
DIAD, PPh3, IPA
THF
Br
6
Scheme 1. Preparation of various thienyl bromides.

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5815
acylation of anisole with 5-bromo-2-methylthiophene-3-carbonyl
chloride, formed form 5-bromo-2-chlorothiophene-3-carboxylic
acid 8 with oxalyl chloride, generated the desired diarylketone 9
in 83% yield. The reduction of diarylketone 2 by triethylsilane in
the presence of boron trifluoride etherate provided aglycon 10 in
quantitative yield. A copper-catalyzed halogen exchange reaction
was performed to prepare thienyl iodides 11 from the correspond-
ing bromides 10 using N,N0-dimethylethylenediamine ligand at
high temperature (120 °C).17 Phenol 12 was generated via demeth-
ylation of aglycon 10 with BBr3. Allylation of aglycon 12 with allyl
bromide under basic conditions, followed by copper-catalyzed hal-
ogen exchange reaction in the presence of NaI, CuI, and N,N0-
dimethylethylenediamine ligand at high temperature (approx
120 °C), produced the corresponding iodide 14 in high yield.17
The general procedures for addition of organometallic com-
pound to gluconolactone which were utilized in this study are
illustrated in Scheme 3. Thus, lithium-bromine exchange of bro-
mide 3 using n-butyllithium, followed by addition of the nascent
lithiated aromatic compound to gluconolactone, produced a mix-
ture of the corresponding lactols 15. Alternatively, a mixture of lac-
tols 16 was smoothly prepared via lithium-iodine exchange of 11
using (trimethylsilyl)methyllithium.18
The synthesis of a target compound, b-anomer of tetraol 20 was
illustrated in Scheme 4. First, the lactol 15 was converted in situ to
the desilylated O-methyl lactols by treatment with methansulfonic
acid in methanol at cold conditions (ꢀ78 to ꢀ50 °C). The reduction
of the anomeric methoxy group of lactol 17 using triethylsilane
and boron trifluoride diethyl etherate was performed to generate
O
Me
O
Me
O
Me
S
1) (COCl)2, cat. DMF, CH2Cl2
S
pyridium tribromide
AcOH
S
Br
OH
OH
2) anisole, AlCl3, CH2Cl2
Br
O
7
8
9
O
O
Me
Me
Et 3SiH, BF3OEt2
CH2Cl2
NaI, CuI, N1,N2-dimethylethane-1,2-diamine
S
S
S
1,4-dioxane
I
Br
Br
10
11
BBr3
CH2Cl2
O
OH
Me
Me
allyl bromide, Cs2CO3
S
acetone
Br
13
12
O
Me
NaI, CuI, N1,N2-dimethylethane-1,2-diamine
S
1,4-dioxane
I
14
Scheme 2. Preparation of various thienyl iodides.
O
Cl
O
O
TMSO
TMSO
S
O
OTMS
O
, n-BuLi
Cl
OTMS
TMSO
TMSO
OH
S
Toluene/THF
OTMS
OTMS
Br
15
3
O
Me
O
O
TMSO
TMSO
S
O
OTMS
O
, TMSCH2Li
Me
OTMS
TMSO
TMSO
OH
OTMS
OTMS
S
THF
I
16
11
Scheme 3. Addition of lithiated compound to gluconolactone.

5816
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
O
O
Cl
Cl
S
S
O
Et 3SiH, BF3OEt2
CH3CN/ CH2Cl2
CH3SO3H
MeOH
O
TMSO
TMSO
HO
HO
OH
OTMS
OMe
OH
OTMS
OH
17
15
O
O
Cl
Cl
S
S
O
Ac2O, Et3N, DMAP
CH2Cl2
AcO
O
HO
HO
OAc
AcO
OH
OAc
OH
19
18
O
Cl
S
O
NaOMe
MeOH
HO
HO
OH
OH
71a
Scheme 4. Preparation of C-aryl glucoside containing 2-chlorothiophene.
the corresponding tetraol 18 (b-anomer/
a
-anomer = 3:1). Finally,
Another route of synthesis of chlorothiophene-containing C-
aryl glucoside was shown in Scheme 8. Reduction of acid 1 with
borane dimethylsulfide, followed by protection of the resulting
alcohol 31 with TIPSCl produced bromide 32. Metal–halogen ex-
change of halogenated compound 32 with n-butyllithium, fol-
lowed by addition of the nascent organometallic compound to
perbenzylated gluconolactone, produced a mixture of the corre-
peracetylation using Et3N and acetic anhydride in the presence of
DMAP, subsequently selective crystallization from ethanol, fol-
lowed by hydrolysis using sodium methoxide yielded the target
compound 20 in 48% yield for the five steps.
The phenol 4 was used as a starting material in preparing the
chlorothiophene-containing C-aryl glucoside as shown in Scheme
5. Protection of phenol 4 with TBDMS group, followed by addition
of the nascent organometallic compound 21 to TMS-protected
gluconolactone 1, produced a mixture of the corresponding lactols
22. Alternatively, the phenol 12 was used as a starting material in
preparing the methylthiophene-containing C-aryl glucoside as
shown in Scheme 5. Copper-catalyzed halogen exchange reaction
using NaI, CuI, and N,N0-dimethylethylenediamine ligand at high
temperature (120 °C) and protection of phenol 23 with TBDMS
group generated iodide 24. Finally, a mixture of lactols 25 was
smoothly prepared via lithium-iodine exchange of 24 using
(trimethylsilyl)methyllithium.
The synthesis of b-anomer of pentaol 71c was shown in Scheme
6. First, the lactol 22 was converted in situ to the desilylated
O-methyl lactols by treatment with methansulfonic acid in metha-
nol at low temperature (ꢀ78 to ꢀ50 °C). The reduction of the
anomeric methoxy group of lactol 26 using triethylsilane and
boron trifluoride diethyl etherate was performed to generate the
corresponding mixture of pentaol 27. Finally, peracetylation using
Et3N and acetic anhydride in the presence of DMAP, selective crys-
tallization from ethanol, followed by hydrolysis using sodium
methoxide yielded the pentaol 71c in 20% yield for the five steps.
The derivatization of pentaol 71a was shown in Scheme 7. The
phenol 29 was alkylated with alkyl halide under basic conditions to
provide ether 71f, albeit in low yield.
sponding lactols 33 (b-anomer/a-anomer = 2:1), which were re-
duced using triethylsilane and boron trifluoride diethyl etherate,
followed by desilylation, afforded alcohol 35 in 89% yield for three
steps. The alcohol 35 was converted to benzoate with benzoyl
chloride in the presence of Et3N. A mixture of
a,b-isomers of 36
was resolved after selective crystallization from ethanol to produce
the required b-isomer 36 in high separation yield. Hydrolysis of
benzoate 36 with lithium hydroxide monohydrate in aqueous eth-
anol and THF solution generated b-anomer of alcohol 37 in high
yield. The alcohol 37 was converted to bromide 38 using phospho-
rus tribromide and pyridine. The bromide 38 was coupled with
corresponding boronic acid in the presence of Pd catalyst and
Cs2CO3. Finally, peracetylation using Et3N and acetic anhydride in
the presence of DMAP, followed by hydrolysis using sodium meth-
oxide yielded the target compound 41 in 17% yield for the two
steps.19
An efficient conversion of 3-methylthiophene-2-carbonyl chlo-
ride (42) into a Weinreb amide 43 was achieved by treatment of
N,O-dimethylhydroxylamine hydrochloride and TEA under mild
conditions in quantitative yield. Reaction of Weinreb amide 43
with proper organometallic nucleophiles, such as Grignard
reagents (Scheme 9, route a) and organolithium reagents (Scheme
9, route b), produced the desired ketones 44. Bromothiophenyl
intermediate 45 was obtained in good yield (60–70%) by bromina-

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5817
OTBDMS
OH
TBDMSCl, imidazole, DMAP
DMF
Cl
Cl
S
S
Br
Br
21
4
OTBDMS
Cl
O
O
TMSO
TMSO
S
OTMS
O
, n-BuLi
OTMS
TMSO
TMSO
OH
OTMS
OTMS
22
Toluene,THF
OH
OH
Me
Me
NaI, CuI, N1,N2-dimethylethane-1,2-diamine
S
S
1,4-dioxane
I
Br
12
23
O
O
TMSO
TMSO
OTBDMS
OTMS
Me
TBDMSCl, imidazole, DMAP
DMF
, TMSCH2Li
OTMS
S
THF
I
24
OTBDMS
Me
S
O
TMSO
TMSO
OH
OTMS
25
OTMS
Scheme 5. Preparation of chlorothiophene-containing C-aryl glucoside intermediate.
tion at the thiophene ring of 44 using bromine generated from
pyridinium tribromide in glacial acetic acid. The reduction of diaryl
ketone 45 to compound 46 was accomplished by treatment of ex-
cess triethylsilane in the presence of boron trifluoride etherate. The
copper-catalyzed halogen exchange reaction was performed to
produce thienyl iodides 47 from the corresponding bromides 46
using N,N0-dimethylethylenediamine ligand at high temperature
(approx 110 °C) (Scheme 9).
desired 3-bromo-4-methylthiophenyl compound 72h and 3,4-
dimethylthiophenyl compound 72j, respectively. Also, bromide
56 underwent Ullmann-type coupling and concomitant total
deacetylation to provide 3-methoxy-4-methylthiophenyl com-
pound 72i.21
2.2. Structure–activity relationship studies
Lithiated thienyl moieties were prepared from the correspond-
ing thienyl iodides 47 by treatment of (trimethylsilyl)methyllith-
ium and coupled with persilylated lactone 49 at low temperature
(ꢀ50 to ꢀ40 °C). The resulting lactols 49 were converted in situ
to the desilylated O-methyl lactols 50 by treatment with methane-
sulfonic acid in methanol at low temperature (ꢀ78 to ꢀ50 °C). The
anomeric methoxy group of 50 was reduced using triethylsilane
and BF3 etherate to generate the corresponding tetraol 51. The
small amount of a-anomer and other impurities in the crude tetra-
ols 51 were removed by reverse phase preparative HPLC to afford
the target compounds 51 (Scheme 10).
Another approach toward C-aryl glucoside 3-methylthiophene
is described in Scheme 11. Thus, bromide 56 underwent Suzuki-
type coupling reaction (trimethylboroxine, tricyclohexylphosphine
tetrafluoroborate, Pd(OAc)2, K3PO4, aq toluene, reflux for 18 h) to
transform to dimethylthiophene 57 in 70% yield.20 Hydrolysis of
56 and 57 with sodium methoxide in methanol produced the
The cell-based SGLT2 AMG (methyl-a-D-glucopyranoside) inhi-
bition assay was performed to evaluate the inhibitory effects of all
prepared compounds on hSGLT2 activities.22,23 Exploration of the
SAR began by replacing the phenyl moiety at the proximal ring
position of dapagliflozin with 5-chloro-4-benzylthiophenyl
moiety. These initial results are shown in Table 1. Substitution of
4-methoxy on the phenyl ring showed moderate activity (71a,
IC50 = 86.5 nM). One more carbon homologation provided an im-
proved activity (71b, IC50 = 34.6 nM), while further elongation at
the position slightly decreased in vitro inhibitory activity against
hSGLT2. Olefin, alkyne or oxygen-containing chains are tolerable
at this position, but none of them appeared more potent than the
simple ethoxy group. Replacement for the substituent with
4-hydroxy (71c, IC50 = 34.6 nM) reduced inhibitory activity against
hSGLT2 in approximately fourfold, suggesting that acidic substitu-
ents may not be tolerated at this position. Replacement for the sub-
stituent with thiomethyl 71j improved inhibitory activity against

5818
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
OTBDMS
OH
Cl
Cl
S
S
Et3SiH, BF3OEt2
CH3CN/ CH2Cl2
O
CH3SO3H
MeOH
O
TMSO
TMSO
HO
HO
OH
OTMS
OTMS
OMe
OH
26
22
OH
OAc
OH
Cl
Cl
S
S
Ac2O, Et3N, DMAP
CH2Cl 2
O
O
AcO
AcO
HO
HO
OAc
OH
28
27
OAc
OH
OH
Cl
S
NaOMe
MeOH
O
HO
HO
OH
OH
71c
Scheme 6. Preparation of pentaol-containing 2-chlorothiophene.
OH
O
Cl
Cl
S
propargyl bromide, K2CO3
O
S
O
HO
HO
acetone
HO
HO
OH
OH
OH
71f
71a
OH
Scheme 7. Example of derivatization at phenol.
hSGLT2 in approximately threefold. However, homologated ethyl-
sulfide 71k lost inhibitory activity against hSGLT2 in fourfold.
Branched alkoxides at this position were also tested. Interestingly,
isopropoxy 71l improved inhibitory activity against hSGLT2 in
threefold (IC50 = 11.9 nM) than ethoxy 71b (IC50 = 34.6 nM). How-
ever, cyclic moiety such as cyclopentyloxy (71m, IC50 = 57.2 nM)
or tetrahydrofuran-3-yloxy (71n, IC50 = 162 nM) dropped activity
in fivefold or even 15-fold, respectively, suggesting that simple
branched chain is more appropriate than bulkier ring structure
for this region. Introduction of an alkyl chain at the C-4 position
of benzyl group demonstrated promising in vitro inhibitory activ-
ity against hSGLT2. Among benzylthiophenyl compounds thus
tested, 4-ethylbenzylthiophene (71p, IC50 = 4.47 nM) turned out
to be more active than the corresponding 4-methyl group (71o,
IC50 = 60.2 nM) or 4-propyl group (71q, IC50 = 10.3 nM), implying
the importance of appropriate lipophilicity for the region. On the
other hand, diaryl-type 71r in this series exhibited less favorable
activity (71r, IC50 = 91.3 nM). Of note is that replacement of
chlorine with methyl at the C-5 position of thiophene consistently
improved inhibitory activity against hSGLT2 across the board
(71s–71w) in approximately twofold to eightfold, respectively.
Table 2 shows the structure–activity consequences upon alter-
nation of the substituents pattern at the proximal thiphenyl ring.
Compounds bearing alkoxides at C-4 position of the distal benzyl
ring were prepared and tested. These compounds showed only
moderate hSGLT2 inhibitory activities (72a, IC50 = 71.4 nM; 72b,
IC50 = 68.9 nM). Subsequently, compounds with halogen or small
aliphatic chains were prepared and tested. Either chloro 72c
(IC50 = 451 nM) or t-butyl 49 (IC50 = 88.3 nM) did not improve
in vitro activity against hSGLT2. Among benzylthiophenyl com-
pounds tested, 4-ethylbenzylthiophene (72f, IC50 = 24.8 nM)
turned out to be more active than the corresponding 4-methyl
group (72e, IC50 = 69.6 nM) or 4-propyl group (72g, IC50
=
59.8 nM). Since 4-ethylbenzylthiophenyl 72f showed the favorable
inhibitory activity against hSGLT2, exploration was driven around
C-3 position of thiophene with maintaining 4-ethylbenzyl at the
C-5 position of thiophenyl ring. Bromine at C-3 position of
thiophene 72h demonstrated twofold improvement in inhibitory
activity against hSGLT2. Incorporation of methyl at C-3 position
of thiophene 72i resulted in similar level of inhibitory activity
(IC50 = 29.3 nM), while methoxide at the particular position
demonstrated twofold loss of inhibitory activity against hSGLT2
(72i, IC50 = 49.5 nM). Thus, the series of thiophenyl compounds in
Table 2 appear to show slightly less inhibitory activity than the
series in Table 1, indicating the importance of attachment position
of substituents on the proximal thiophenyl ring.
3. Conclusion
In the present study, C-glucosides incorporating thiophenyl
motif at the proximal ring position were exploited in order to

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5819
O
OH
Cl
Cl
Cl
S
TIPSCl, imidazole, DMAP
S
BH3 SMe2
THF
Br
Br
OTIPS
Cl
OH
DMF
S
Br
32
31
1
Cl
O
O
BnO
OTIPS
S
OTIPS
S
OBn , n-BuLi
BnO
O
O
Et3Si H, BF3OEt2
CH2Cl2
BnO
BnO
OBn
OH
OBn
OBn
BnO
BnO
THF
OBn
OBn
34
33
Cl
Cl
O
O
OH
S
S
O
O
LiOHH2O
THF/MeOH/H2O
BnO
BnO
benzoyl chloride, Et3N
CH2Cl2
TBAF
THF
OBn
OBn
BnO
BnO
OBn
Cl
OBn
35
36
Cl
OH
Br
S
S
4-methylboronic acid
Ph(PPh3)4,Cs2CO3
O
O
PBr 3, cat. pyridine
ether
BnO
BnO
BnO
BnO
Toluene/EtOH
OBn
OBn
OBn
OBn
38
37
Me
Me
Cl
Cl
S
S
NaOMe
MeOH
O
O
TMSOTf
Ac2O
AcO
AcO
BnO
BnO
OAc
OBn
OAc
OBn
39
40
Me
Cl
S
O
HO
HO
OH
71o
Scheme 8. Another route toward chlorothiophene-containing C-aryl glucoside.
OH
discover and develop novel SGLT2 targeting antidiabetic agents.
We envisioned that replacement of the proximal ring of dapagliflo-
zin with a phenyl surrogate would be a worthy approach to mod-
ulate physicochemical property. Along the line, two series of novel
C-aryl glucoside SGLT2 inhibitors containing thiophenyl ring at
the proximal ring postion were designed and synthesized. Among
the compounds tested, 5-chloro-4-(ethylbenzyl)thiophene 71p
showed the best in vitro inhibitory activities to date in this series
(IC50 = 4.47 nM) against hSGLT2. Although this series of com-
pounds failed to advance as a development candidate, the current
chemistry shown in here allowed us to synthesize difficult, yet
desirable targets in a relatively straightforward fashion.
4. Experimental
4.1. General methods
All reactions are conducted under an inert atmosphere at room
temperature, unless otherwise noted. All reagents were purchased
at the highest commercial quality and used without further purifi-
cation, unless otherwise indicated. Microwave reaction was con-
ducted with a Biotage Initiator microwave reactor. NMR spectra
were obtained on a Varian 400-MR (400 MHz 1H) spectrometer.
NMR spectra were recorded in ppm (d) relative to tetramethylsil-
ane (d = 0.00) as an internal standard unless stated otherwise and

5820
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
R
R
a)
O
Me
Me
HCl
HN
Me
, THF
O
N
O
, Et3N
XMg
S
O
CHCl3
S
Cl
or
S
O
R
4 4
, n-BuLi
,THF
4 3
b)
42
Br
R
R
R
Me
Me
Me
N
-
H+ Br3
Et3SiH, BF3OEt2
CH3CN/ CH2Cl2
NaI, Cu(I)I, DMED
Dioxane
Acetic acid
S
I
S
S
O
Br
Br
4 7
4 6
4 5
Scheme 9. Preparation of various 3-methylthiophene-2-carbonyl chloride.
R
R
Me
Me
O
O
OH
TMSO
TMSO
O
S
, TMSCH2Li
S
TMSO
TMSO
I
OTMS
THF
OTMS
OTMS
OTMS
48
49
R
R
Me
Me
Me
O
O
Et3SiH,BF3.OEt2
CH2Cl 2/ CH3CN
MeSO3H
MeOH
S
O
HO
HO
S
HO
HO
OH
OH
OH
OH
51
50
Scheme 10. Preparation of C-aryl glucoside containing 3-methylthiophene.
are reported as follows: chemical shift, multiplicity (s = singlet,
d = doublet, t = triplet, q = quartet, quint = quintet, sext = sextet,
m = multiplet, and br = broad), coupling constant, and integration.
Mass spectra were obtained with an Agilent 6110 quadruple LC-
MSD (ESI+). Preparative HPLC purifications were performed on a
GilsonÒ purification system. For preparative HPLC, ca. 100 mg of
a product was injected in 1 mL of methanol onto a SunFire Prep
p-anisaldehyde solution as visualizing agents or HPLC analysis on
an Agilent 1200 series system.
4.2. Chemistry
4.2.1. Synthesis of 5-bromo-2-chlorothiophene-3-carboxylic
acid (1)
C18 OBD 5
l
m 30 ꢁ 100 mm Column with a 30 min gradient from
The title compound 1 was prepared from commercially avail-
able 2-chloro-3-methylthiophene according to the known proce-
dure (US 5840917 A1).
5 to 90% acetonitrile in water and a 45 mL/min flow rate. BiotageÒ
SP1 and Isolera purification systems were used for normal phase
column chromatography with ethyl acetate and hexane. Flash
chromatography was performed using E. Merck 230–400 mesh sil-
ica gel according to the procedure of Still et al. Reactions were
monitored by either thin-layer chromatography (TLC) on
0.25 mm E. Merck silica gel plates (60F-254) using UV light and
4.2.2. Synthesis of (5-bromo-2-chlorothiophen-3-yl)(4-meth-
oxyphenyl)methanone (2)
To a solution of acid 1 (2.0 g, 8.28 mmol) in CH2Cl2 (50 mL) were
added oxalyl chloride (0.87 mL, 9.94 mmol) and catalytic amounts

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5821
Br
Br
BrMg
O
N
TES / BF3OEt2
DCM / ACN
Br2
Br
S
AcOH
Br
THF
S
S
S
O
O
O
55
53
52
54
O
O
TMSO
TMSO
OTMS
OTMS
Br
MsOH
TES/ BF3OEt2
DCM / ACN
Ac2O
O
S
MeOH / THF
DMAP
pyridine
DCM
AcO
AcO
TMSCH2Li
THF
OAc
56
OAc
NaOMe
MeOH
B
O
B
O
B
Br
O
, Pd(OAc)2
O
S
HO
HO
CuO / KI
OH
72h
NaOMe / MeOH
PBF4 , K3PO4
OH
3
toluene / water
O
O
O
O
S
HO
HO
S
OAc
AcO
NaOMe
MeOH
S
HO
HO
OH
OH
AcO
OH
72j
57
72i
OAc
OH
Scheme 11. Alternative route toward C-aryl glucoside-containing 3-methylthiophene.
of DMF at room temperature. The mixture was stirred at room
temperature for 3 h. The mixture was evaporated in vacuo and
dried under high vacuum. The crude acid chloride was dissolved
with CH2Cl2 (30 mL) and cooled to 0 °C. To the mixture was added
anisole (0.9 mL, 8.28 mmol) at 0 °C and stirred at 0 °C for 5 min. To
the reaction mixture was added AlCl3 (1.2 g, 8.28 mmol) portion-
wise at 0 °C. The mixture was stirred at 0 °C for 30 min, warmed
up to room temperature and stirred at room temperature for
15 h. The mixture was poured into ice-water and extracted with
CH2Cl2 (50 mL ꢁ 2). The combined organic layer was dried over
MgSO4, filtered, and concentrated in vacuo. The residue was
purified by silica column chromatography (BiotageÒ) to provide
the intermediate 2 (2.68 g, 98%). 1H NMR (400 MHz, CDCl3) d
7.83 (d, J = 8.4 Hz, 2H), 7.01 (s, 1H), 6.96 (d, J = 8.4 Hz, 2H), 3.90
(s, 3H).
4.2.4. Synthesis of 4-((5-bromo-2-chlorothiophen-3-yl)methyl)-
phenol (4)
To a solution of thiophene 3 (5.44 g, 17.1 mmol) in CH2Cl2
(50 mL) was added boron tribromide (20 mL, 1 M in CH2Cl2) at
0 °C. The mixture was warmed up to room temperature slowly
and stirred at room temperature for 3 h. To the mixture was added
aq 1 N HCl solution (35 mL) dropwise at 0 °C and H2O was added to
the mixture. The mixture was extracted with EtOAc (50 mL ꢁ 2).
The combined organic layer was dried over MgSO4, filtered, and
concentrated in vacuo. The crude product 4 was dried under high
vacuum and used without further purification (5.1 g, 99%).
4.2.5. Synthesis of 5-bromo-2-chloro-3-(4-propoxybenzyl)-
thiophene (5)
To a solution of phenol 4 (500 mg, 1.65 mmol) in acetone
(25 mL) were added 1-iodopropane (0.5 mL, 4.95 mmol) and
Cs2CO3 (460 mg, 4.95 mmol) at room temperature. The mixture
was stirred at 60 °C for 12 h. The reaction mixture was cooled to
room temperature and filtered off through celiteÒ. The filtrate
was concentrated in vacuo. The residue was purified by silica col-
umn chromatography (BiotageÒ) to provide the intermediate 5
(600 mg, 99%). 1H NMR (400 MHz, CDCl3) d 7.06 (d, J = 8.0 Hz,
2H), 6.84 (d, J = 8.0 Hz, 2H), 6.66 (s, 1H), 3.89 (t, J = 6.8 Hz, 2H),
3.79 (s, 2H), 1.79 (sextet, J = 7.2 Hz, 2H), 1.03 (t, J = 7.2 Hz, 3H).
4.2.3. Synthesis of 5-bromo-2-chloro-3-(4-methoxybenzyl)-
thiophene (3)
To a solution of methanone 2 (2.68 g, 8.08 mmol) in CH2Cl2/
CH3CN (20:20 mL) were added triethylsilane (3.9 mL, 24.2 mmol)
and boron trifluoride diethyl etherate (3.1 mL, 24.2 mmol) at
0 °C. The mixture was warmed up to room temperature slowly
and stirred at room temperature for 15 h. To the mixture was
added aq saturated K2CO3 solution (50 mL) slowly and extracted
with EtOAc (50 mL ꢁ 2). The combined organic layer was dried
over MgSO4, filtered, and concentrated in vacuo. The residue was
purified by silica column chromatography (BiotageÒ) to provide
the desired product 3 (2.09 g, 82%). 1H NMR (400 MHz, CDCl3) d
7.09 (d, J = 8.0 Hz, 2H), 6.83 (d, J = 8.0 Hz, 2H), 6.66 (s, 1H), 3.80
(s, 2H), 3.78 (s, 3H).
4.2.6. Synthesis of 5-bromo-2-chloro-3-(4-isopropoxybenzyl)-
thiophene (6)
To a solution of phenol 4 (1 g, 3.29 mmol) and PPh3 (1.8 g,
6.58 mmol) in THF (25 mL) was added DIAD (1.3 mL, 6.58 mmol)
at room temperature. The mixture was stirred at room

5822
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
Table 1
In vitro inhibitory activity against hSGLT2
X
S
R
O
HO
HO
OH
OH
Compound
X
R
hSGLT2a IC50 (nM)
Compound
X
R
hSGLT2a IC50 (nM)
O
O
Dapagliflozine
0.49 0.04b
71l
Cl
11.9
OMe
OEt
71a
71b
Cl
Cl
86.5
34.6
71m
71n
Cl
Cl
57.2
162
H
O
O
OH
O
71c
71d
Cl
Cl
140
71o
71p
Cl
Cl
60.2
4.47
65.0
O
O
71e
71f
Cl
Cl
54.6
111
71q
71r
Cl
Cl
10.3
91.3
F
S
OMe
O
71g
Cl
94
71s
Me
11.5
O
OEt
OH
O
O
O
71h
71i
Cl
Cl
115
71t
Me
Me
8.73
50.2
O
70.7
71u
SMe
SEt
71j
Cl
Cl
12.8
48.4
71v
Me
Me
27.5
21.1
71k
71w
F
S
a
These data were determined by single determination.
The IC50 value was obtained by in-house multiple determinations.
b
temperature for 30 min. 2-Propanol (0.4 mL, 4.94 mmol) was
added to the reaction mixture. The reaction mixture was stirred
at room temperature for 20 h. The mixture was extracted with
EtOAc/H2O (50:50 mL) and was dried over MgSO4, filtered, and
concentrated in vacuo. The residue was purified by silica column
chromatography (BiotageÒ) to provide the desired product 6
(913 mg, 80%). 1H NMR (400 MHz, CDCl3) d 7.06 (d, J = 8.4 Hz,
2H), 6.81 (d, J = 8.4 Hz, 2H), 6.67 (s, 1H), 4.54–4.47 (m, 1H), 3.79
(s, 2H), 1.38 (d, J = 6.0 Hz, 6H).
mixture was cooled to room temperature and poured into H2O
(350 mL) with stirring. The product was precipitated and the sus-
pension was stirred at room temperature for 1 h. The precipitated
solid was filtered, washed with H2O (500 mL) and dried under high
vacuum at 45 °C. The crude product was used without further puri-
fication (3.18 g, 84%). 1H NMR (400 MHz, CDCl3) d 7.38 (s, 1H), 2.70
(s, 3H); MS calcd for C6H5BrO2S (MW 221.07), found [M+H]+ 221.
4.2.8. Synthesis of (5-bromo-2-methylthiophen-3-yl)(4-meth-
oxyphenyl)methanone (9)
4.2.7. Synthesis of 5-bromo-2-methylthiophene-3-carboxylic
acid (8)
To a solution of acid 8 (10 g, 45.2 mmol) in CH2Cl2 (200 mL)
were added oxalyl chloride (4.8 mL, 54.3 mmol) and catalytic
amounts of DMF at room temperature. The mixture was stirred
at room temperature for 2 h. The mixture was concentrated in va-
cuo and dried under high vacuum. The crude acid chloride was dis-
solved with CH2Cl2 (200 mL) and cooled to 0 °C. To the mixture was
added anisole (5.0 mL, 45.2 mmol) at 0 °C and stirred at 0 °C for
To a solution of 2-methylthiophene-3-carboxylic acid (2.44 g,
17.2 mmol, prepared from commercially available thiophene-3-
carboxylic acid according to the known procedure (US 5840917
A1)) was added pyridium tribromide (6.3 g) in AcOH (30 mL) at
room temperature. The mixture was stirred at 40 °C for 4 h. The

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5823
Table 2
(d, J = 8.8 Hz, 2H), 6.83 (d, J = 8.8 Hz, 2H), 3.78 (s, 3H), 3.74 (s,
2H), 2.31 (s, 2H).
In vitro inhibitory activity against hSGLT2
Me
X
4.2.10. Synthesis of 5-iodo-3-(4-methoxybenzyl)-2-methyl-
thiophene (11)
R
O
S
HO
To a solution of bromide 10 (1.5 g, 5.05 mmol) in 1.4-dioxane
(10 mL) were added NaI (1.5 g, 10.1 mmol), CuI (0.1 g, 0.51 mmol)
and N1,N2-dimethylethane-1,2-diamine (0.11 mL, 1.01 mmol) at
room temperature. The reaction mixture was evacuated and back-
filled with nitrogen. The mixture was stirred 120 °C for 18 h. The
mixture was cooled to room temperature and filtered off through
Celite. The filtrate was extracted with EtOAc/H2O (50:50 mL). The
organic layer was dried over MgSO4, filtered, and concentrated in
vacuo. The crude product 11 was dried under high vacuum and
used without further purification (2.32 g, 79%).
HO
OH
OH
Compound
X
R
hSGLT2a IC50 (nM)
Dapagliflozine
0.49 0.04b
OEt
OMe
Cl
72a
72b
H
H
71.4
68.9
4.2.11. Synthesis of 4-((5-bromo-2-methylthiophen-3-yl)-
methyl)phenol (12)
72c
72d
H
H
451
To a solution of bromide 10 (9.7 g, 32.6 mmol) in CH2Cl2
(100 mL) was added boron tribromide (40 mL, 39.2 mmol, 1 M in
CH2Cl2) dropwise at 0 °C. The mixture was warmed up to room
temperature slowly and stirred at room temperature for 3 h. To
the mixture was added aq. 1 N HCl solution (200 mL) dropwise at
0 °C. The mixture was extracted with CH2Cl2 (150 mL ꢁ 2). The
combined organic layer was dried over MgSO4, filtered, and con-
centrated in vacuo. The residue was purified by silica column chro-
matography (BiotageÒ) to provide the desired product 12 (5.64 g,
61%). 1H NMR (400 MHz, CDCl3) d 6.99 (d, J = 6.0 Hz, 2H), 6.75 (d,
J = 6.0 Hz, 1H), 6.65 (s, 1H), 4.73 (s, 1H), 3.73 (s, 2H), 2.31 (s, 3H).
t -Bu
88.3
72e
72f
H
H
69.6
24.8
72g
H
59.8
72h
72i
72j
Br
12.4
49.5
29.3
4.2.12. Synthesis of 3-(4-(allyloxy)benzyl)-5-bromo-2-methyl-
thiophene (13)
OMe
Me
To a solution of phenol 12 (860 mg, 3.04 mmol) in acetone
(20 mL) were added allyl bromide (0.5 mL, 4.56 mmol) and Cs2CO3
(2.0 g, 6.08 mmol) at room temperature. The mixture was stirred at
60 °C for 2 h. The reaction mixture was cooled to room tempera-
ture and filtered off through celite. The filtrate was concentrated
in vacuo. The residue was purified by silica column chromatogra-
phy (BiotageÒ) to provide the intermediate 13 (906 mg, 92%). 1H
a
These data were determined by single determination.
The IC50 value was obtained by in-house multiple determinations.
b
NMR (400 MHz, CDCl3)
d 7.07 (d, J = 8.4 Hz, 2H), 6.85 (d,
J = 8.4 Hz, 2H), 6.19–5.99 (m, 1H), 5.40 (doublet and doublet,
J = 17.2, 1.6 Hz, 1H), 5.27 (doublet and doublet, J = 10.8, 1.2 Hz,
1H), 4.51 (d, J = 5.2 Hz, 2H), 3.80 (s, 2H), 2.31 (s, 3H).
5 min. To the reaction mixture was added AlCl3 (6.0 g, 45.2 mmol)
portionwise at 0 °C. The mixture was stirred at 0 °C for 2 h, warmed
up to room temperature and stirred at room temperature for 15 h.
The mixture was poured into ice-water and extracted with CH2Cl2
(100 mL ꢁ 2). The combined organic layer was dried over MgSO4,
filtered, and concentrated in vacuo. The crude product was tritulat-
ed with MeOH (100 mL) and stirred at 0 °C for 1 h. The precipitated
solid was filtered and washed with MeOH (50 mL). The solid was
dried under high vacuum and used without further purification
(11.7 g, 83%). 1H NMR (400 MHz, CDCl3) d 7.78 (d, J = 6.8 Hz, 2H),
7.26 (s, 1H), 6.95 (d, J = 6.8 Hz, 2H), 3.88 (s, 3H), 2.53 (s, 3H); MS
calcd for C13H11BrO2S (MW 311.19), found [M+H]+ 311.
4.2.13. Synthesis of 5-iodo-3-(4-methoxybenzyl)-2-methylthio-
phene (14)
To a solution of bromide 13 (906 mg, 2.80 mmol) in 1.4-dioxane
(10 mL) were added NaI (841 mg, 5.61 mmol), CuI (54 mg,
0.28 mmol) and N1,N2-dimethylethane-1,2-diamine (0.06 mL,
0.56 mmol) at room temperature. The reaction mixture was evac-
uated and backfilled with nitrogen. The mixture was stirred
120 °C for 18 h. The mixture was cooled to room temperature
and filtered off through CeliteÒ. The filtrate was extracted with
EtOAc/H2O (50:50 mL). The organic layer was dried over MgSO4,
filtered, and concentrated in vacuo. The crude product 14 was
dried under high vacuum and used without further purification
(846 mg, 81%).
4.2.9. Synthesis of 5-bromo-3-(4-methoxybenzyl)-2-methyl-
thiophene (10)
To a solution of methanone 9 (11.7 g, 37.6 mmol) in CH2Cl2/
CH3CN (90:90 mL) were added triethylsilane (15.0 mL, 94.0 mmol)
and boron trifluoride diethyl etherate (12.0 mL, 94.0 mmol) at 0 °C.
The mixture was warmed up to room temperature slowly and stir-
red at room temperature for 15 h. To the mixture was added aq
saturated K2CO3 solution (100 mL) slowly and extracted with
EtOAc (100 mL ꢁ 2). The combined organic layer was dried over
MgSO4, filtered, and concentrated in vacuo. The residue was puri-
fied by silica column chromatography (BiotageÒ) to provide the de-
sired product 10 (11.2 g, 100%). 1H NMR (400 MHz, CDCl3) d 7.03
4.2.14. Synthesis of (3R,4S,5R,6R)-2-(5-chloro-4-(4-methoxy-
benzyl)thiophen-2-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimeth-
ylsilyloxy)methyl)-tetrahydro-2H-pyran-2-ol (15)
To a solution of bromide 3 (2.09 g, 5.06 mmol) in toluene/THF
(30:15 mL) at ꢀ78 °C under an atmosphere of nitrogen was added
dropwise n-butyllithium (2.5 M in hexanes, 2.6 mL, 6.58 mmol),
and the mixture was stirred for 40 min at the same temperature.
Then
a
solution of TMS-protected gluconolactone (2.4 g,

5824
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
6.58 mmol) in toluene (20 mL) was added dropwise, and the mix-
ture was stirred for 1 h at the same temperature. The reaction mix-
ture was quenched by addition of saturated ammonium chloride.
After complete addition, the solution was gradually raised to room
temperature. The organic layer was separated and the aqueous
layer was extracted with EtOAc. The combined organic layers were
washed with brine, dried over anhydrous MgSO4, filtered and con-
centrated in vacuo to yield the title compound 15, which was car-
ried on to the next step without further purification.
2H), 5.04 (t, J = 9.6 Hz, 1H), 4.50 (d, J = 9.6 Hz, 1H), 4.27–4.13 (m,
2H), 3.83–3.71 (m, 6H), 2.08 (s, 3H), 2.03 (s, 3H), 1.99 (s, 3H),
1.78 (s, 3H); MS calcd for C26H29ClO10S (MW 569.02), found
[M+Na]+ 591.
4.2.17. Synthesis of (2R,3R,4S,5S,6R)-2-(5-chloro-4-(4-meth-
oxybenzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71a)
To a suspension of acetate 19 (1.37 g, 2.41 mmol) in MeOH
(20 mL) was added NaOMe (25 wt % in MeOH, 0.3 mL) at room
temperature. The mixture was stirred at room temperature for
1 h. Glacial AcOH was added to the mixture to acidify the mixture.
The mixture was concentrated under reduced pressure. The resi-
due was purified by prep HPLC (C18) to provide the title compound
71a (604 mg, 63%). 1H NMR (400 MHz, DMSO-d6) d 7.13 (d,
J = 8.4 Hz, 2H), 6.86 (d, J = 8.4 Hz, 2H), 6.82 (s, 1H), 5.18 (d,
J = 6.0 Hz, 1H), 4.99 (d, J = 5.2 Hz, 1H), 4.94 (d, J = 5.6 Hz, 1H),
4.46 (t, J = 6.0 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.77 (s, 2H), 3.73–
3.63 (m, 4H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.27–3.16 (m, 2H),
3.11–3.01 (m, 2H); MS calcd for C18H21ClO6S (MW 400.87), found
[M+Na]+ 423.
4.2.15. Synthesis of (3R,4S,5R,6R)-2-(4-(4-methoxybenzyl)-5-
methylthiophen-2-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimeth-
ylsilyloxy)methyl)-tetrahydro-2H-pyran-2-ol (16)
A mixture of TMS-protected gluconolactone (2.6 g, 5.47 mmol)
and iodide 11 (1.57 g, 4.56 mmol) in THF (30 mL) was added tri-
methylsilylmethyl lithium (1.0 M in pentane, 9.6 mL, 9.58 mmol)
at ꢀ65 °C. The mixture was allowed to slowly warm to ꢀ45 °C over
2 h. To a mixture was added aq saturated NaHCO3 solution to
quench the reaction. After dilution with water, the mixture was
stirred at room temperature for 30 min and extracted with EtOAc.
The organic layer was dried over anhydrous MgSO4, filtered and
concentrated in vacuo. The crude title compound 16 was carried
on to the next step without further purification.
4.2.18. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-ethoxybenzyl)thio-
phen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol
(71b)
4.2.16. Synthesis of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(5-
chloro-4-(4-methoxybenzyl)thiophen-2-yl)-tetrahydro-2H-
pyran-3,4,5-triyl triacetate (19)
1H NMR (400 MHz, DMSO-d6) d 7.11 (d, J = 8.8 Hz, 2H), 6.86–
6.81 (m, 3H), 5.18 (d, J = 5.6 Hz, 1H), 4.99 (d, J = 5.2 Hz, 1H), 4.94
(d, J = 5.2 Hz, 1H), 4.46 (t, J = 5.6 Hz, 1H), 4.17 (d, J = 9.6 Hz, 1H),
3.98 (quartet, J = 7.2 Hz, 2H), 3.77 (s, 2H), 3.71–3.63 (m, 1H), 3.40
(quintet, J = 6.0 Hz, 1H), 3.26–3.17 (m, 2H), 3.11–3.02 (m, 2H),
1.30 (t, J = 7.2 Hz, 3H); MS calcd for C19H23ClO6S (MW 414.09),
found [M+Na]+ 437.
Step 1: To a solution of crude alcohol 15 (3.57 g, 5.06 mmol) in
THF (50 mL) were added CH3SO3H (0.6 N in MeOH, 17 mL,
10.1 mmol) at ꢀ78 °C. The mixture was allowed to slowly warm
to ꢀ40 °C. To a mixture was added aq saturated NaHCO3 solution
(50 mL) to quench the reaction. After dilution with water, the mix-
ture was stirred at room temperature for 30 min and extracted
with EtOAc (100 mL). The organic layer was dried over anhydrous
MgSO4, filtered and concentrated in vacuo. The crude
(3R,4S,5S,6R)-2-(5-chloro-4-(4-methoxybenzyl)thiophen-2-yl)-6-
(hydroxymethyl)-2-methoxy-tetrahydro-2H-pyran-3,4,5-triol (17)
(2.43 g) was carried on to the next step without further
purification.
Step 2: To a solution of compound 17 (2.43 g) in CH2Cl2/CH3CN
(25:25 mL) were added triethylsilane (1.8 mL, 11.3 mmol) and bor-
on trifluoride diethyl etherate (1.5 mL, 11.3 mmol) at ꢀ60 °C. The
mixture was allowed to slowly warm to ꢀ5 °C. To a mixture was
added aq saturated NaHCO3 solution (20 mL) to quench the reac-
tion and extracted with EtOAc (100 mL). The combined organic
layer was dried over MgSO4, filtered, and concentrated in vacuo.
The crude (3R,4S,5S,6R)-2-(5-chloro-4-(4-methoxybenzyl)thio-
phen-2-yl)-6-(hydroxymethyl)-2-methoxy-tetrahydro-2H-pyran-
3,4,5-triol (18) (2.17 g) was carried on to the next step without
further purification.
Step 3: To a solution of compound 18 (2.17 g) in CH2Cl2 (50 mL)
were added Ac2O (5.1 mL, 54.1 mmol), Et3N (7.5 mL, 54.1 mmol)
and catalytic amount of DMAP at 0 °C. The mixture was stirred at
0 °C for 15 min and at room temperature for 15 h. The mixture
was concentrated under reduced pressure to remove volatiles.
The residue was diluted with EtOAc (50 mL), washed with H2O
(100 mL), aq 1 N HCl solution (100 mL) and brine (100 mL) succes-
sively. The organic layer was dried over MgSO4, filtered, and con-
centrated in vacuo. The residue was purified by silica column
chromatography (BiotageÒ) to provide the mixture of beta and al-
pha anomers of the titled compound 19 (1.9 g). The anomeric mix-
ture of 19 was recrystallized with EtOH (50 mL). The precipitate
was collected by filtration and washed with cold EtOH (30 mL)
and dried under high vacuum to obtain the title compound 19
(1.37 g, 48% (5-steps)). 1H NMR (400 MHz, CDCl3) d 7.05 (d,
J = 8.8 Hz, 2H), 7.82 (d, J = 8.8 Hz, 2H), 6.57 (s, 1H), 5.27–5.12 (m,
4.2.19. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-(methylthio)benzyl)-
thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-
triol (71j)
1H NMR (400 MHz, DMSO-d6) d 7.23–7.14 (m, 4H), 6.84 (s, 1H),
5.19 (d, J = 5.6 Hz, 1H), 4.99 (d, J = 5.2 Hz, 1H), 4.94 (d, J = 5.2 Hz,
1H), 4.45 (t, J = 6.0 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.81 (s, 2H),
3.72–3.63 (m, 1H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.25–3.16 (m,
2H), 3.11–3.01 (m, 2H), 2.43 (s, 3H); MS calcd for C18H21ClO5S2
(MW 416.94), found [M+Na]+ 439.
4.2.20. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-(ethylthio)benzyl)thio-
phen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol
(71k)
1H NMR (400 MHz, DMSO-d6) d 7.25 (d, J = 8.0 Hz, 2H), 7.16 (d,
J = 8.0 Hz, 2H), 6.85 (s, 1H), 5.20 (d, J = 6.0 Hz, 1H), 5.06–4.91 (m,
2H), 4.46 (t, J = 5.6 Hz, 1H), 4.18 (d, J = 9.6 Hz, 1H), 3.81 (s, 2H),
3.71–3.63 (m, 1H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.26–3.17 (m,
2H), 3.12–3.02 (m, 2H), 2.93 (quartet, J = 7.2 Hz, 2H), 2.93 (t,
J = 7.2 Hz, 3H); MS calcd for C19H23ClO5S2 (MW 430.97), found
[M+Na]+ 453.
4.2.21. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-isopropoxybenzyl)-
thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-
triol (71l)
1H NMR (400 MHz, DMSO-d6) d 7.10 (d, J = 8.4 Hz, 2H), 6.86–
6.79 (m, 3H), 5.18 (d, J = 6.0 Hz, 1H), 4.99 (d, J = 6.0 Hz, 1H), 4.94
(d, J = 5.6 Hz, 1H), 4.54 (septet, J = 6.0 Hz, 1H), 4.46 (t, J = 6.0 Hz,
1H), 4.17 (d, J = 9.2 Hz, 1H), 3.76 (s, 2H), 3.71–3.63 (m, 1H), 3.40
(quintet, J = 6.0 Hz, 1H), 3.26–3.17 (m, 2H), 3.13–3.03 (m, 2H),
1.23 (d, J = 6.0 Hz, 6H); MS calcd for C20H25ClO6S (MW 428.93),
found [M+Na]+ 451.

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5825
4.2.22. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-(cyclopentyloxy)-
4.2.28. Synthesis of (4-((5-bromo-2-chlorothiophen-3-yl)-
benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71m)
methyl)phenoxy)(tert-butyl)dimethylsilane (21)
To a solution of phenol 4 (3.0 g, 9.88 mmol) in DMF (20 mL)
were added TBDMSCl (1 M in CH2Cl2, 20 mL, 19.8 mmol), imidazole
(2.1 g, 29.6 mmol) and DMAP (0.25 g, 1.98 mmol) at room temper-
ature. The mixture was stirred at ambient temperature for 14 h.
The mixture was extracted with EtOAc/H2O (75:250 mL). The or-
ganic layer was dried over MgSO4, filtered, and concentrated in va-
cuo. The residue was purified by silica column chromatography
(BiotageÒ) to provide the title compound 21 (4.12 g, 99%). 1H
NMR (400 MHz, CDCl3) d 6.99–6.91 (m, 2H), 6.83 (s, 1H), 6.81–
6.72 (m, 2H), 3.64 (s, 2H), 0.96 (s, 9H), 0.15 (s, 6H).
1H NMR (400 MHz, DMSO-d6) d 7.10 (d, J = 8.8 Hz, 2H), 6.82 (d,
J = 8.8 Hz, 2H), 6.79 (s, 1H), 5.18 (d, J = 5.6 Hz, 1H), 4.99 (d,
J = 4.8 Hz, 1H), 4.94 (d, J = 5.2 Hz, 1H), 4.75 (quintet, J = 6.0 Hz,
1H), 4.45 (t, J = 6.0 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.76 (s, 2H),
3.70–3.54 (m, 1H), 3.39 (quintet, J = 6.0 Hz, 1H), 3.26–3.17 (m,
2H), 3.13–3.03 (m, 2H), 1.94–1.82 (m, 2H), 1.73–1.63 (m, 4H),
1.61–1.52 (m, 2H); MS calcd for C22H27ClO6S (MW 454.96), found
[M+Na]+ 477.
4.2.23. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-(tetrahydrofuran-3-
yloxy)benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-
2H-pyran-3,4,5-triol (71n)
4.2.29. Synthesis of (3R,4S,5R,6R)-2-(4-(4-(tert-butyldimethyl-
silyloxy)benzyl)-5-chlorothiophen-2-yl)-3,4,5-tris(trimethyl-
silyloxy)-6-((trimethylsilyloxy)methyl)-tetrahydro-2H-pyran-2-
ol (22)
To a solution of bromide 22 (4.12 g, 9.86 mmol) in toluene/THF
(40:20 mL) at ꢀ78 °C under an atmosphere of nitrogen was added
dropwise n-butyllithium (2.5 M in hexanes, 4.0 mL, 9.86 mmol),
and the mixture was stirred for 45 min at the same temperature.
1H NMR (400 MHz, DMSO-d6) d 7.12 (d, J = 8.4 Hz, 2H), 6.87–
6.79 (m, 3H), 5.18 (d, J = 5.2 Hz, 1H), 5.02–4.91 (m, 2H), 4.45 (t,
J = 5.2 Hz, 1H), 4.17 (t, J = 9.6 Hz, 1H), 3.88–3.63 (m, 8H), 3.40
(quintet, J = 6.0 Hz, 1H), 3.26–3.17 (m, 2H), 3.12–3.01 (m, 2H),
2.23–2.12 (m, 1H), 1.98–1.88 (m, 1H); MS calcd for C21H25ClO7S
(MW 456.94), found [M+Na]+ 479.
Then
a
solution of TMS-protected gluconolactone (3.8 g,
8.22 mmol) in toluene (20 mL) was added dropwise, and the mix-
ture was stirred for 1 h at the same temperature. The reaction mix-
ture was quenched by addition of saturated ammonium chloride.
After complete addition, the solution was gradually raised to room
temperature. The organic layer was separated and the aqueous
layer was extracted with EtOAc. The combined organic layers were
washed with brine, dried over anhydrous MgSO4, filtered and con-
centrated in vacuo to yield the title compound 15, which was car-
ried on to the next step without further purification.
4.2.24. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-((5-(4-
fluorophenyl)thiophen-2-yl)methyl)thiophen-2-yl)-6-
(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol (71r)
1H NMR (400 MHz, DMSO-d6) d 7.65–7.57 (m, 2H), 7.29 (d,
J = 3.6 Hz, 1H), 7.25–7.18 (m, 2H), 6.95 (s, 1H), 6.90 (d, J = 3.2 Hz,
1H), 5.23 (d, J = 5.2 Hz, 1H), 5.01 (d, J = 4.8 Hz, 1H), 4.96 (d,
J = 4.8 Hz, 1H), 4.47 (t, J = 6.0 Hz, 1H), 4.21 (d, J = 9.2 Hz, 1H), 4.05
(s, 2H), 3.74–3.65 (m, 1H), 3.47–3.35 (m, 1H), 3.28–3.18 (m, 2H),
3.15–3.03 (m, 2H); MS calcd for C21H20ClFO5S2 (MW 470.96), found
[M+Na]+ 493.
4.2.30. Synthesis of 4-((5-iodo-2-methylthiophen-3-yl)methyl)-
phenol (23)
4.2.25. (2R,3S,4S,5R,6R)-2-(Hydroxymethyl)-6-(4-(4-methoxy-
benzyl)-5-methylthiophen-2-yl)-tetrahydro-2H-pyran-3,4,5-
triol (71s)
To a solution of bromide 12 (960 mg, 3.39 mmol) in 1.4-dioxane
(10 mL) were added NaI (1.1 g, 6.78 mmol), CuI (100 mg,
0.34 mmol) and N1,N2-dimethylethane-1,2-diamine (0.1 mL,
0.68 mmol) at room temperature. The reaction mixture was evac-
uated and backfilled with nitrogen. The mixture was stirred
120 °C for 18 h. The mixture was cooled to room temperature
and filtered off through celiteÒ. The filtrate was extracted with
EtOAc/H2O (50:50 mL). The organic layer was dried over MgSO4,
filtered, and concentrated in vacuo. The crude product 23 was
dried under high vacuum and used without further purification
(540 mg, 48%).
1H NMR (400 MHz, DMSO-d6) d 7.09 (d, J = 8.4 Hz, 2H), 6.83 (d,
J = 8.4 Hz, 2H), 6.69 (s, 1H), 4.95–4.87 (m, 3H), 4.42 (t, J = 5.6 Hz,
1H), 4.12 (d, J = 9.2 Hz, 1H), 3.73–3.62 (m, 6H), 3.39 (quintet,
J = 6.0 Hz, 1H), 3.23–3.13 (m, 2H), 3.12–3.03 (m, 2H),
2.33 (s, 3H); MS calcd for
C19H24O6S (MW 380.46), found
[M+Na]+ 403.
4.2.26. (2R,3R,4S,5S,6R)-2-(4-(4-Ethoxybenzyl)-5-methylthio-
phen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol
(71t)
4.2.31. Synthesis of tert-butyl(4-((5-iodo-2-methylthiophen-3-
yl)methyl)phenoxy)dimethylsilane (24)
1H NMR (400 MHz, DMSO-d6) d 7.07 (d, J = 8.4 Hz, 2H), 6.83 (d,
J = 8.4 Hz, 2H), 6.69 (s, 1H), 4.94–4.87 (m, 3H), 4.43 (t, J = 6.0 Hz,
1H), 4.12 (d, J = 9.2 Hz, 1H), 3.96 (quartet, J = 7.2 Hz, 2H), 3.68 (s,
2H), 3.65 (quartet and doublet, J = 5.6, 1.6 Hz, 1H), 3.40 (quintet,
J = 6.0 Hz, 1H), 3.23–3.14 (m, 2H), 3.13–3.05 (m, 2H), 2.32 (s, 3H),
1.29 (t, J = 7.2 Hz, 3H); MS calcd for C20H26O6S (MW 394.48), found
[M+Na]+ 417.
To a solution of phenol 23 (0.54 g, 1.64 mmol) in DMF (15 mL)
were added TBDMSCl (1 M in CH2Cl2, 3.5 mL, 3.28 mmol), imidaz-
ole (0.35 g, 4.92 mmol) and DMAP (50 mg, 0.33 mmol) at room
temperature. The mixture was stirred at ambient temperature for
15 h. The mixture was extracted with EtOAc/H2O (50:150 mL).
The organic layer was dried over MgSO4, filtered, and concentrated
in vacuo. The residue was purified by silica column chromatogra-
phy (BiotageÒ) to provide the title compound 24 (0.65 g, 89%). 1H
NMR (400 MHz, CDCl3) d 7.00–6.91 (m, 2H), 6.83 (s, 1H), 6.77–
6.71 (m, 2H), 3.75 (s, 2H), 2.34 (s, 3H), 0.97 (s, 9H), 0.17 (s, 6H).
4.2.27. (2R,3R,4S,5S,6R)-2-(4-((5-(4-fluorophenyl)thiophen-2-
yl)methyl)-5-methylthiophen-2-yl)-6-(hydroxymethyl)-tetra-
hydro-2H-pyran-3,4,5-triol (71w)
1H NMR (400 MHz, DMSO-d6) d 7.63–7.56 (m, 2H), 7.27 (d,
J = 3.2 Hz, 1H), 7.24–7.17 (m, 2H), 6.86 (d, J = 3.6 Hz, 1H), 6.82 (s,
1H), 4.96 (d, J = 6.0 Hz, 1H), 4.94 (d, J = 4.8 Hz, 1H), 4.90 (d,
J = 5.2 Hz, 1H), 4.43 (t, J = 5.6 Hz, 1H), 4.16 (d, J = 9.2 Hz, 1H), 4.00
(s, 2H), 3.66 (quartet and doublet, J = 5.6, 1.6 Hz, 1H), 3.39
(quintet, J = 6.0 Hz, 1H), 3.25–3.17 (m, 2H), 3.15–3.05 (m, 2H),
2.36 (s, 3H); MS calcd for C22H23FO5S2 (MW 450.54), found m/z
[M+Na]+ 473.
4.2.32. Synthesis of (3R,4S,5R,6R)-2-(4-(4-(tert-butyldimethyl-
silyloxy)benzyl)-5-methylthiophen-2-yl)-3,4,5-tris(trimethyl-
silyloxy)-6-((trimethylsilyloxy)methyl)-tetrahydro-2H-pyran-2-
ol (25)
A mixture of TMS-protected gluconolactone (0.65 g, 1.46 mmol)
and iodide 24 (0.82 g, 1.75 mmol) in THF (20 mL) was added tri-
methylsilylmethyl lithium (1.0 M in pentane, 3.1 mL, 3.07 mmol)

5826
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
at ꢀ65 °C. The mixture was allowed to slowly warm to ꢀ45 °C over
1 h. To a mixture was added aq saturated NaHCO3 solution to
quench the reaction. After dilution with water, the mixture was
stirred at room temperature for 30 min and extracted with EtOAc.
The organic layer was dried over anhydrous MgSO4, filtered and
concentrated in vacuo. The crude title compound 25 was carried
on to the next step without further purification.
3.62 (m, 3H), 3.43–3.37 (m, 1H), 3.24–3.14 (m, 3H), 3.12–3.02
(m, 2H); MS calcd for C17H19ClO6S (MW 386.85), found [M+Na]+
409.
4.2.35. Synthesis of (2R,3R,4S,5S,6R)-2-(4-(4-hydroxybenzyl)-5-
methylthiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71u)
1H NMR (400 MHz, DMSO-d6) d 9.15 (s, 1H), 6.96 (d, J = 8.4 Hz,
2H), 6.66 (d, J = 8.4 Hz, 2H), 6.64 (s, 1H), 4.97–4.88 (m, 3H), 4.41
(t, J = 6.0 Hz, 1H), 4.12 (d, J = 9.2 Hz, 1H), 3.71–3.61 (m, 3H), 3.41
(quintet, J = 6.0 Hz, 1H), 3.24–3.14 (m, 2H), 3.13–3.03 (m, 2H),
4.2.33. Synthesis of (2R,3R,4S,5R,6R)-2-(4-(4-acetoxybenzyl)-5-
chlorothiophen-2-yl)-6-(acetoxymethyl)-tetrahydro-2H-pyran-
3,4,5-triyl triacetate (28)
Step 1: To a solution of crude alcohol 22 (1.51 g, 1.88 mmol) in
THF (50 mL) were added CH3SO3H (0.6 N in MeOH, 6.3 mL,
3.76 mmol) at ꢀ78 °C. The mixture was allowed to slowly warm to
ꢀ40 °C. To a mixture was added aq saturated NaHCO3 solution
(50 mL) to quench the reaction. After dilution with water, the
mixture was stirred at room temperature for 30 min and
extracted with EtOAc (100 mL). The organic layer was dried over
anhydrous MgSO4, filtered and concentrated in vacuo. The
crude (3R,4S,5S,6R)-2-(5-chloro-4-(4-hydroxybenzyl)thiophen-2-
yl)-6-(hydroxymethyl)-2-methoxy-tetrahydro-2H-pyran-3,4,5-triol
(26) (1.1 g) was carried on to the next step without further
purification.
Step 2: To a solution of compound 26 (1.1 g) in CH2Cl2/CH3CN
(20:20 mL) were added triethylsilane (0.70 mL, 4.14 mmol) and bor-
on trifluoride diethyl etherate (0.55 mL, 4.14 mmol) at ꢀ60 °C. The
mixture was allowed to slowly warm to ꢀ5 °C. To a mixture was
added aq saturated NaHCO3 solution (25 mL) to quench the reaction
and extracted with EtOAc (100 mL). The combined organic layer was
dried over MgSO4, filtered, and concentrated in vacuo. The crude
(3R,4S,5S,6R)-2-(5-chloro-4-(4-hydroxybenzyl)thiophen-2-yl)-6-
(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol (27) (0.85 g)
was carried on to the next step without further purification.
Step 3: To a solution of compound 27 (0.85 g) in CH2Cl2 (20 mL)
were added Ac2O (2.1 mL, 22.0 mmol), Et3N (3.1 mL, 22.0 mmol)
and catalytic amount of DMAP at 0 °C. The mixture was stirred at
0 °C for 15 min and at room temperature for 12 h. The mixture
was concentrated under reduced pressure to remove volatiles.
The residue was diluted with EtOAc (50 mL), washed with H2O
(100 mL), aq. 1 N HCl solution (100 mL) and brine (100 mL) succes-
sively. The organic layer was dried over MgSO4, filtered, and con-
centrated in vacuo. The residue was purified by silica column
chromatography (BiotageÒ) to provide the mixture of beta and al-
pha anomers of the title compound 28 (0.67 g). The anomeric mix-
ture of 28 was recrystallized with EtOH (20 mL). The precipitate
was collected by filtration and washed with cold EtOH (20 mL)
and dried under high vacuum to obtain b-anomer of the title com-
pound 28 (0.41 g, 33% (four-steps)). 1H NMR (400 MHz, CDCl3) d
7.15 (d, J = 8.4 Hz, 2H), 6.99 (d, J = 8.4 Hz, 2H), 6.59 (s, 1H), 5.27–
5.13 (m, 2H), 5.04 (d, J = 9.6 Hz, 1H), 4.51 (d, J = 10.0 Hz, 1H),
4.27–4.13 (m, 2H), 3.89–3.77 (m, 3H), 2.28 (s, 3H), 2.08 (s, 3H),
2.31 (s, 3H); MS calcd for
C18H22O6S (MW 366.43), found
[M+Na]+ 389.
4.2.36. Synthesis of (2R,3R,4S,5S,6R)-2-(5-chloro-4-(4-(prop-2-
ynyloxy)benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-
2H-pyran-3,4,5-triol (71f)
To a solution of phenol 71a (124 mg, 0.320 mmol) in acetone
(10 mL) were added propargyl bromide (80 wt % in toluene, 1.7 g,
11.2 mmol) and Cs2CO3 (1.5 g, 11.2 mmol) at room temperature.
The mixture was stirred at 50 °C for 20 h. The reaction mixture
was cooled to room temperature and filtered off through celite28.
The filtrate was concentrated in vacuo. The residue was purified by
prep HPLC (C18) to provide the title compound 71f (51 mg, 38%). 1H
NMR (400 MHz, DMSO-d6) d 7.14 (d, J = 8.8 Hz, 2H), 6.92 (d,
J = 8.8 Hz, 2H), 6.84 (s, 1H), 5.20 (d, J = 5.6 Hz, 1H), 5.02 (d,
J = 4.8 Hz, 1H), 4.97 (d, J = 5.2 Hz, 1H), 4.74 (d, J = 2.4 Hz, 2H),
4.46 (d, J = 5.6 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.78 (s, 2H), 3.71–
3.64 (m, 1H), 3.56–3.51 (m, 1H), 3.40 (quintet, J = 6.0 Hz, 1H),
3.25–3.16 (m, 2H), 3.13–3.02 (m, 2H); MS calcd for C20H21ClO6S
(MW 424.90), found [M+Na]+ 447.
4.2.37. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-propoxybenzyl)thio-
phen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol
(71d)
1H NMR (400 MHz, DMSO-d6) d 7.11 (d, J = 8.4 Hz, 2H), 6.88–
6.81 (m, 3H), 5.21 (d, J = 6.0 Hz, 1H), 5.03 (d, J = 4.0 Hz, 1H), 4.97
(d, J = 5.2 Hz, 1H), 4.47 (t, J = 6.0 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H),
3.87 (t, J = 7.6 Hz, 2H), 3.77 (s, 2H), 3.69–3.62 (m, 1H), 3.41 (quin-
tet, J = 6.0 Hz, 1H), 3.24–3.17 (m, 2H), 3.13–3.02 (m, 2H), 1.70 (sex-
tet, J = 7.2 Hz, 2H), 0.96 (t, J = 7.2 Hz, 3H); MS calcd for C20H25ClO6S
(MW 428.93), found [M+Na]+ 451.
4.2.38. (2R,3R,4S,5S,6R)-2-(4-(4-(Allyloxy)benzyl)-5-chlorothio-
phen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol
(71e)
1H NMR (400 MHz, DMSO-d6) d 7.12 (d, J = 8.4 Hz, 2H), 6.88 (d,
J = 8.4 Hz, 2H), 6.83 (s, 1H), 6.08–5.96 (m, 1H), 5.37 (doublet and
quartet, J = 17.2, 1.6 Hz, 1H), 5.27–5.17 (m, 2H), 5.01 (d,
J = 4.8 Hz, 1H), 4.96 (d, J = 5.2 Hz, 1H), 4.56–4.51 (m, 2H), 4.47 (t,
J = 5.6 Hz, 1H), 4.17 (d, J = 9.6 Hz, 1H), 3.77 (s, 2H), 3.71–3.63 (m,
1H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.26–3.16 (m, 2H), 3.11–3.02
(m, 2H); MS calcd for C20H23ClO6S (MW 426.91), found [M+Na]+
449.
2.04 (s, 3H), 1.99 (s, 3H), 1.77 (s, 3H); MS calcd for C27H29ClO11
S
(MW 597.03), found [M+Na]+ 619.
4.2.34. Synthesis of (2R,3R,4S,5S,6R)-2-(5-chloro-4-(4-hydroxy-
benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71c)
4.2.39. (2R,3R,4S,5S,6R)-2-(4-(4-(But-2-ynyloxy)benzyl)-5-
chlorothiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-
3,4,5-triol (71g)
To a suspension of acetate 28 (413 mg, 0.617 mmol) in MeOH
(15 mL) was added NaOMe (25 wt % in MeOH, 0.2 mL) at room
temperature. The mixture was stirred at room temperature for
1 h. Glacial AcOH was added to the mixture to acidify the mixture.
The mixture was concentrated under reduced pressure. The resi-
due was purified by prep HPLC (C18) to provide the title compound
71c (130 mg, 55%). 1H NMR (400 MHz, DMSO-d6) d 7.00 (d,
J = 8.4 Hz, 2H), 6.81 (s, 1H), 6.67 (d, J = 8.0 Hz, 2H), 5.19 (br s,
1H), 4.98 (br s, 2H), 4.47 (br s, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.73–
1H NMR (400 MHz, DMSO-d6) d 7.13 (d, J = 8.4 Hz, 2H), 6.88 (d,
J = 8.4 Hz, 2H), 6.84 (s, 1H), 5.18 (d, J = 4.8 Hz, 1H), 4.98 (d,
J = 4.8 Hz, 1H), 4.93 (d, J = 5.2 Hz, 1H), 4.68 (quartet, J = 2.4 Hz,
2H), 4.45 (t, J = 5.2 Hz, 1H), 4.17 (t, J = 9.2 Hz, 1H), 3.78 (s, 2H),
3.71–3.62 (m, 1H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.25–3.17 (m,
2H), 3.13–3.02 (m, 2H), 3.40 (t, J = 1.8 Hz, 3H); MS calcd for
C21H23ClO6S (MW 438.92), found m/z 461.

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5827
4.2.40. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-(2-methoxyethoxy)-
benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71h)
ture was stirred for 40 min at the same temperature. Then a solu-
tion of benzyl-protected gluconolactone (4.7 g, 8.75 mmol) in THF
(20 mL) was added dropwise, and the mixture was stirred for 2.5 h
at the same temperature. The reaction mixture was quenched by
addition of saturated ammonium chloride. After complete addi-
tion, the solution was gradually raised to room temperature. The
organic layer was separated and the aqueous layer was extracted
with EtOAc. The combined organic layers were washed with brine,
dried over anhydrous MgSO4, filtered and concentrated in vacuo to
yield the title compound 33, which was carried on to the next step
without further purification.
1H NMR (400 MHz, DMSO-d6) d 7.10 (d, J = 8.4 Hz, 2H), 6.86 (d,
J = 8.8 Hz, 2H), 6.83 (s, 1H), 5.18 (d, J = 6.0 Hz, 1H), 5.00 (d,
J = 4.8 Hz, 1H), 4.95 (d, J = 5.6 Hz, 1H), 4.46 (t, J = 6.0 Hz, 1H), 4.17
(d, J = 9.2 Hz, 1H), 4.07–4.02 (m, 2H), 3.77 (s, 2H), 3.71–3.49 (m,
3H), 3.39 (quintet, J = 6.0 Hz, 1H), 3.29 (s, 3H), 3.25–3.17 (m, 2H),
3.12–3.02 (m, 2H); MS calcd for C20H25ClO7S (MW 444.93), found
[M+Na]+ 467.
4.2.41. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-(2-ethoxyethoxy)-
benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71i)
4.2.46. Synthesis of ((2-chloro-5-((3R,4S,5R,6R)-3,4,5-
tris(benzyloxy)-6-(benzyloxymethyl)-tetrahydro-2H-pyran-2-
yl)thiophen-3-yl)methoxy)triisopropylsilane (34)
1H NMR (400 MHz, DMSO-d6) d 7.12 (d, J = 8.4 Hz, 2H), 6.86 (d,
J = 8.8 Hz, 2H), 6.82 (s, 1H), 5.19 (d, J = 5.6 Hz, 1H), 5.00 (d,
J = 4.4 Hz, 1H), 4.95 (d, J = 5.2 Hz, 1H), 4.46 (t, J = 5.6 Hz, 1H), 4.17
(d, J = 9.2 Hz, 1H), 4.08–4.02 (m, 2H), 3.77 (s, 2H), 3.71–3.62 (m,
3H), 3.48 (quartet, J = 7.2 Hz, 2H), 3.39 (quintet, J = 6.0 Hz, 1H),
3.27–3.15 (m, 2H), 3.12–3.03 (m, 2H), 1.12 (t, J = 7.2 Hz, 3H); MS
calcd for C21H27ClO7S (MW 458.95), found [M+Na]+ 481.
To a solution of alcohol 33 (8.53 g, 10.1 mmol) in CH2Cl2
(50 mL) were added triethylsilane (3.3 mL, 20.2 mmol) and boron
trifluoride diethyl etherate (2.6 mL, 20.2 mmol) at ꢀ60 °C. The
mixture was allowed to slowly warm to ꢀ20 °C. To a mixture
was added aq saturated K2CO3 solution (50 mL) to quench the reac-
tion. The mixture was evaporated under reduced pressure to re-
move CH2Cl2 and extracted with EtOAc (100 mL). The combined
organic layer was dried over MgSO4, filtered, and concentrated in
vacuo to yield the title compound 34 (8.22 g), which was carried
on to the next step without further purification.
4.2.42. (2R,3R,4S,5S,6R)-2-(4-(4-(Allyloxy)benzyl)-5-methyl-
thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-
triol (71v)
1H NMR (400 MHz, DMSO-d6) d 7.08 (d, J = 8.8 Hz, 2H), 6.84 (d,
J = 8.4 Hz, 2H), 6.70 (s, 1H), 6.09–5.97 (m, 1H), 5.37 (quartet and
doublet, J = 17.6, 1.6 Hz, 1H), 5.23 (quartet and doublet, J = 17.6,
1.6 Hz, 1H), 4.98–4.87 (m, 3H), 4.51 (doublet and triplet, J = 5.2,
1.6 Hz, 2H), 4.40 (t, J = 5.2 Hz, 1H), 4.12 (d, J = 9.2 Hz, 1H), 3.71 (s,
2H), 3.69–3.62 (m, 1H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.26–3.15
(m, 2H), 3.14–3.03 (m, 2H), 2.31 (s, 3H); MS calcd for C21H26O6S
(MW 406.49), found [M+Na]+ 429.
4.2.47. Synthesis of (2-chloro-5-((3R,4S,5R,6R)-3,4,5-
tris(benzyloxy)-6-(benzyloxymethyl)-tetrahydro-2H-pyran-2-
yl)thiophen-3-yl)methanol (35)
To a solution of compound 34 (8.22 g) in THF (50 mL) was
added TBAF (1 M in THF, 20 mL, 19.9 mmol) dropwise at 0 °C.
The mixture was stirred at room temperature for 2 h. The mixture
was extracted with EtOAc/H2O (100:250 mL). The organic layer
was dried over MgSO4, filtered, and concentrated in vacuo. The res-
idue was purified by silica column chromatography (BiotageÒ) to
provide the title compound 35 (5.2 g, 89% (3-steps)). MS calcd for
4.2.43. Synthesis of (5-bromo-2-chlorothiophen-3-yl)methanol
(31)
To a solution of acid 1 (3.0 g, 12.4 mmol) in THF (50 mL) were
added borane dimethylsulfide complex (10 M in THF, 3.2 mL,
31.1 mmol) at 0 °C. The mixture was stirred at 0 °C for 15 min, at
room temperature for 45 min, and at 65 °C for 2 h. The reaction
mixture was cooled to 0 °C. To the mixture were added MeOH
(30 mL), H2O (250 mL) dropwise at 0 °C. The mixture was extracted
with EtOAc (100 mL). The organic layer was dried over MgSO4, fil-
tered, and concentrated in vacuo to obtain the title compound 31
(2.8 g, 99%). The crude alcohol 31 was carried on to the next step
without further purification.
C
39H39ClO6S (MW 671.24), found [M+Na]+ 693.
4.2.48. Synthesis of (2-chloro-5-((2R,3R,4S,5R,6R)-3,4,5-
tris(benzyloxy)-6-(benzyloxymethyl)-tetrahydro-2H-pyran-2-
yl)thiophen-3-yl)methyl benzoate (36)
To a solution of alcohol 35 (5.2 g, 7.75 mmol) in CH2Cl2 (50 mL)
were added Et3N (3.5 mL, 23.3 mmol) and benzoyl chloride
(1.2 mL, 10.1 mmol) at 0 °C. The mixture was allowed to slowly
warm to room temperature and stirred at room temperature for
15 h. The mixture was washed with aq saturated NaHCO3 solution.
The organic layer was dried over MgSO4, filtered, and concentrated
in vacuo. The residue was purified by silica column chromatogra-
phy (BiotageÒ) to provide the mixture of beta and alpha anomers
of the title compound (6.1 g). The anomeric mixture of 36 was
recrystallized with EtOH (50 mL). The precipitate was collected
by filtration and washed with cold EtOH (30 mL) and dried under
high vacuum to obtain b-anomer of the title compound 36
(4.64 g, 77%). 1H NMR (400 MHz, CDCl3) d 8.01 (d, J = 8.4 Hz, 2H),
7.58–7.52 (m, 1H), 7.44–7.36 (m, 2H), 7.35–7.24 (m, 13H), 7.21–
7.11 (m, 5H), 7.08–7.01 (m, 3H), 5.27 (s, 2H), 4.94 (s, 2H), 4.67–
4.53 (m, 3H), 4.42 (d, J = 9.2 Hz, 1H), 4.24 (d, J = 10.4 Hz, 1H),
3.81–3.69 (m, 4H), 3.62–3.52 (m, 1H), 3.50–3.42 (m, 1H); MS calcd
for C46H43ClO7S (MW 775.35), found [M+Na]+ 797.
4.2.44. Synthesis of (5-bromo-2-chlorothiophen-3-yl)methoxy)-
triisopropylsilane (32)
To a solution of alcohol 31 (2.8 g, 12.3 mmol) in DMF (25 mL)
were added TIPSCl (5.3 mL, 24.6 mmol), imidazole (2.5 g,
36.9 mmol) and DMAP (0.3 g, 2.46 mmol) at room temperature.
The mixture was stirred at ambient temperature for 14 h. The mix-
ture was extracted with EtOAc/H2O (75:250 mL). The organic layer
was dried over MgSO4, filtered, and concentrated in vacuo. The res-
idue was purified by silica column chromatography (Biotage28) to
provide the title compound 32 (4.0 g, 85%). 1H NMR (400 MHz,
CDCl3) d 7.01 (s, 1H), 4.66 (s, 2H), 1.19–1.11 (m, 3H), 1.07 (d,
J = 9.2 Hz, 18H).
4.2.45. Synthesis of (3R,4S,5R,6R)-3,4,5-tris(benzyloxy)-6-
(benzyloxymethyl)-2-(5-chloro-4-((triisopropylsilyloxy)-
methyl)thiophen-2-yl)-tetrahydro-2H-pyran-2-ol (33)
4.2.49. Synthesis of (2-chloro-5-((2R,3R,4S,5R,6R)-3,4,5-
tris(benzyloxy)-6-(benzyloxymethyl)-tetrahydro-2H-pyran-2-
yl)thiophen-3-yl)methanol (37)
To a solution of bromide 32 (4.0 g, 5.06 mmol) in THF (40 mL) at
ꢀ78 °C under an atmosphere of nitrogen was added dropwise n-
butyllithium (2.5 M in hexanes, 4.2 mL, 10.5 mmol), and the mix-
To a solution of benzoate 36 (4.5 g, 5.80 mmol) in THF/MeOH/
H2O (30:10:10 mL) was added LiOH monohydrate (0.73 g,
17.4 mmol) at room temperature. The mixture was stirred at room

5828
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
temperature for 5 h. The mixture was extracted with EtOAc/aq sat-
urated NH4Cl solution (100:100 mL). The organic layer was dried
over anhydrous MgSO4, filtered and concentrated in vacuo to yield
the title compound 37 (3.86 g, 99%), which was carried on to the
next step without further purification. 1H NMR (400 MHz, CDCl3)
d 7.38–7.22 (m, 17H), 7.21–7.15 (m, 2H), 7.13–7.05 (m, 2H), 6.98
(s, 1H), 4.94–4.82 (m, 3H), 4.69–4.62 (m, 3H), 4.59–4.52 (m, 3H),
4.40 (d, J = 9.2 Hz, 1H), 4.22 (d, J = 7.2 Hz, 1H), 3.80–3.68 (m, 4H),
3.62–3.55 (m, 1H), 3.46 (t, J = 8.8 Hz, 1H); MS calcd for C39H39ClO6S
(MW 671.24), found [M+Na]+ 693.
71o (55 mg, 23%) 1H NMR (400 MHz, DMSO-d6) d 7.10 (s, 4H), 6.82
(s, 1H), 5.19 (d, J = 5.6 Hz, 1H), 5.00 (d, J = 4.8 Hz, 1H), 4.95 (d,
J = 5.2 Hz, 1H), 4.46 (t, J = 5.6 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.79
(s, 2H), 3.60–3.51 (m, 1H), 3.40 (quintet, J = 6.0 Hz, 1H), 3.25–
3.16 (m, 2H), 3.11–3.02 (m, 2H), 2.25 (s, 3H); MS calcd for
C
18H21ClO5S (MW 384.87), found [M+Na]+ 407.
4.2.54. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-ethylbenzyl)thiophen-
2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol (71p)
1H NMR (400 MHz, DMSO-d6) d 7.13 (s, 4H), 6.84 (s, 1H), 5.17 (d,
J = 6.0 Hz, 1H), 4.99 (d, J = 5.2 Hz, 1H), 4.93 (d, J = 5.2 Hz, 1H), 4.45
(t, J = 6.0 Hz, 1H), 4.17 (d, J = 9.6 Hz, 1H), 3.80 (s, 2H), 3.71–3.63 (m,
1H), 3.45–3.36 (m, 1H), 3.26–3.17 (m, 2H), 3.13–3.02 (m, 2H), 2.55
(quartet, J = 7.2 Hz, 2H), 1.15 (t, J = 7.6 Hz, 3H); MS calcd for
4.2.50. Synthesis of (2R,3R,4S,5R,6R)-3,4,5-tris(benzyloxy)-2-
(benzyloxymethyl)-6-(4-(bromomethyl)-5-chlorothiophen-2-
yl)-tetrahydro-2H-pyran (38)
To a solution of alcohol 37 (3.86 g, 5.75 mmol) in ether (50 mL)
were added phosphorus tribromide (0.3 mL, 2.88 mmol) and cata-
lytic amount of pyridine at 0 °C. The mixture was allowed to warm
to room temperature and stirred at room temperature for 2 h. The
mixture was extracted with EtOAc/H2O (100:150 mL). The organic
layer was dried over MgSO4, filtered, and concentrated in vacuo.
The organic layer was dried over anhydrous MgSO4, filtered and
concentrated in vacuo to yield the title compound 38 (4.1 g,
97%), which was carried on to the next step without further
purification.
C
19H23ClO5S (MW 398.90), found [M+Na]+ 421.
4.2.55. (2R,3R,4S,5S,6R)-2-(5-Chloro-4-(4-propylbenzyl)thio-
phen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol
(71q)
1H NMR (400 MHz, DMSO-d6) d 7.11 (s, 4H), 6.84 (s, 1H), 5.17 (d,
J = 6.0 Hz, 1H), 4.97 (d, J = 5.2 Hz, 1H), 4.93 (d, J = 5.2 Hz, 1H), 4.44
(t, J = 6.0 Hz, 1H), 4.17 (d, J = 9.2 Hz, 1H), 3.80 (s, 2H), 3.66 (quartet
and doublet, J = 5.6, 1.6 Hz, 1H), 3.41 (quintet, J = 6.0 Hz, 1H), 3.24–
3.17 (m, 2H), 3.12–3.02 (m, 2H), 2.54–2.45 (m, 2H), 1.55 (sextet,
J = 7.2 Hz, 2H), 0.88 (t, J = 7.2 Hz, 3H); MS calcd for C20H25ClO5S
(MW 412.93), found [M+Na]+ 435.
4.2.51. Synthesis of (2R,3R,4S,5R,6R)-3,4,5-tris(benzyloxy)-2-
(benzyloxymethyl)-6-(5-chloro-4-(4-methylbenzyl)thiophen-2-
yl)-tetrahydro-2H-pyran (39)
4.2.56. Synthesis of N-methoxy-N,3-dimethylthiophene-2-
To a solution of bromide 38 (850 mg, 1.16 mmol) in toluene/
EtOH (18:2 mL) were added 4-methylphenylboronic acid
carboxamide (43)
To
a mixture of N,O-dimethylhydroylamine hydrochloride
(200 mg,
1.39 mmol),
tetrakis(triphenylphosphin)palladium
(5.85 g, 60 mmol) and TEA (16.7 mL, 120 mmol) in chloroform
was added 3-methylthiophene-2-carbonyl chloride (42, 4.89 mL,
40 mmol) at 0 °C. Then, the reaction temperature was raised to
room temperature, and maintained for overnight. The reaction
mixture was subsequently washed with aq HCl solution (1 M,
50 mL) and brine. The organic phase was dried MgSO4 and evapo-
rated under vacuum to provide the intermediate 43 (7.47 g,
ꢂ100%) as a yellow oil, which was used without further purifica-
tion. 1H NMR (400 MHz, CDCl3) d 7.37 (d, J = 5.2 Hz, 1H), 6.90 (d,
J = 5.2 Hz, 1H), 3.71 (s, 3H), 3.34 (s, 3H), 2.55 (s, 3H); MS calcd
for C8H11NO2S (MW 185.24), found [M+H]+ 186.
(70 mg, 0.058 mmol) and Cs2CO3 (770 mg, 2.32 mmol) at room
temperature. The mixture was stirred at 120 °C. The mixture was
cooled to room temperature and filtered off thorough silica gel to
remove insoluble materials. The filtrate was extracted with
EtOAc/H2O (100:150 mL). The organic layer was dried over MgSO4,
filtered, and concentrated in vacuo. The residue was purified by sil-
ica column chromatography (BiotageÒ) to provide the title com-
pound 39 (611 mg, 71%). MS calcd for C46H45ClO5S (MW 745.36),
found [M+Na]+ 767.
4.2.52. Synthesis of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(5-
chloro-4-(4-methylbenzyl)thiophen-2-yl)-tetrahydro-2H-
pyran-3,4,5-triyl triacetate (40)
4.2.57. Synthesis of (3-Methylthiophen-2-yl)(4-propylphenyl)-
methanone (44, via route a)
To a solution of compound 39 (611 mg, 0.819 mmol) in acetic
anhydride (15 mL) was added TMSOTf (1.2 mL, 6.55 mmol) at
ꢀ30 °C. The mixture was allowed to slowly warm to room temper-
ature and stirred at room temperature for 2 h. The mixture was
cooled to 0 °C and aq saturated NaHCO3 solution (50 mL) was
added to the mixture at 0 °C to quench the reaction. The mixture
was diluted with EtOAc (50 mL) and washed with aq saturated
NaHCO3 solution (50 mL ꢁ 3). The organic layer was dried over
MgSO4, filtered, and concentrated in vacuo. The residue was puri-
fied by silica column chromatography (BiotageÒ) to provide the ti-
tle compound 40 (339 mg, 75%). MS calcd for C26H29ClO9S (MW
553.02), found [M+Na]+ 575.
To a solution of the Weinreb amide 43 (3.78 g, 20.4 mmol) in
anhydrous THF (61.3 mL) was added dropwise (over a 10-min per-
iod) a solution of 4-n-propylphenylmagnesium bromide (81.6 mL,
0.5 M in THF) under nitrogen atmosphere at 0 °C. The reaction mix-
ture was allowed to warm to room temperature and stirred for
16 h. The mixture was poured into a 1 M HCl solution (50 mL)
and extracted with EtOAc (100 mL). The organic phase was subse-
quently washed with brine, dried over MgSO4 and evaporated un-
der vacuum. The residue was further purified by silica column
chromatography (BiotageÒ) to provide (3-methylthiophen-2-
yl)(4-propylphenyl)methanone (44, 3.15 g, 12.9 mmol, 63%). 1H
NMR (400 MHz, CDCl3)
d 7.76 (d, J = 8.4 Hz, 2H), 7.47 (d,
J = 5.2 Hz, 1H), 7.27 (d, J = 8.0 Hz, 2H), 7.00 (d, J = 4.8 Hz, 1H),
2.66 (t, J = 7.2 Hz, 2H), 2.48 (s, 3H), 1.73–1.64 (m, 2H), 0.96 (t,
4.2.53. Synthesis of (2R,3R,4S,5S,6R)-2-(5-chloro-4-(4-methyl-
benzyl)thiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (71o)
J = 7.2 Hz, 3H); MS calcd for
C15H16OS (MW 244.35), found
[M+H]+ 245.
To a suspension of acetate 40 (339 mg, 0.612 mmol) in MeOH
(15 mL) was added NaOMe (25 wt % in MeOH, 0.2 mL) at room
temperature. The mixture was stirred at room temperature for
1 h. Glacial AcOH was added to the mixture to acidify the mixture.
The mixture was concentrated under reduced pressure. The resi-
due was purified by prep HPLC (C18) to provide the title compound
4.2.58. Synthesis of (5-bromo-3-methylthiophen-2-yl)(4-
propylphenyl)methanone (45)
To
a
solution of (3-methylthiophen-2-yl)(4-propylphe-
nyl)methanone (44, 1.12 g, 4.58 mmol) in acetic acid (4.67 mL)
was added pyridinium tribromide (3.67 g, 11.5 mmol). The

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5829
reaction mixture was heated to 50 °C for 3 h. After cooling
to room temperature, the mixture was poured into water (50 mL)
and extracted with EtOAc (100 mL). The organic phase was dried
over MgSO4 and evaporated under vacuum. The residue was
further purified by silica column chromatography (BiotageÒ) to
provide (5-bromo-3-methylthiophen-2-yl)(4-propylphenyl)meth-
anone (45, 0.95 g, 2.95 mmol, 64%). 1H NMR (400 MHz, CDCl3) d
7.72 (d, J = 8.4 Hz, 2H), 7.27 (d, J = 8.0 Hz, 2H), 6.98 (s, 1H), 2.66
(t, J = 7.6 Hz, 2H), 2.43 (s, 3H), 1.73–1.64 (m, 2H), 0.96 (t,
J = 7.6 Hz, 3H); MS calcd for C15H15BrOS (MW 323.25), found
[M+H]+ 323.
4.2.62. Synthesis of (2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(4-
methyl-5-(4-propylbenzyl)thiophen-2-yl)tetrahydro-2H-pyran-
3,4,5-triol (51)
Step 1: To a solution of 5-iodo-3-methyl-2-(4-propylbenzyl)thi-
ophene (47, 0.95 g, 2.66 mmol) and (3R,4S,5R,6R)-3,4,5-tris(tri-
methylsilyloxy)-6-((trimethylsilyloxy)methyl)tetrahydro-2H-pyr-
an-2-one (200, 1.37 g, 2.93 mmol) in THF (8.53 mL) was added
dropwise (over a 5-min period) a (trimethylsilyl)lithium solution
(5.32 mL, 1.0 M in pentane) under nitrogen atmosphere at ꢀ50 °C.
The reaction temperature was maintained ꢀ40 and ꢀ50 °C for 2 h.
The reaction was quenched with a saturated NaHCO3 solution
(20 mL), and then extracted with EtOAc (50 mL). The organic
phase was dried over MgSO4 and evaporated under vacuum to
provide the crude intermediate ((3R,4S,5R,6R)-2-(4-methyl-5-(4-
propylbenzyl)thiophen-2-yl)-3,4,5-tris(trimethylsilyloxy)-6-((tri-
methylsilyloxy)methyl)tetrahydro-2H-pyran-2-ol) (49).
Step 2: The crude ((3R,4S,5R,6R)-2-(4-methyl-5-(4-propylben-
zyl)thiophen-2-yl)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyl-
oxy)methyl)tetrahydro-2H-pyran-2-ol) (49) was dissolved in
anhydrous THF (13.6 mL). To the resulting solution was added drop-
wise a solution of methanesulfonic acid (0.31 mL in 8 mL MeOH) un-
der nitrogen atmosphere at ꢀ78 °C. The reaction temperature was
maintained ꢀ50 and ꢀ78 °C for 2 h. The reaction was quenched with
a saturated NaHCO3 solution (20 mL), and then extracted with EtOAc
(50 mL). The organic phase was dried over MgSO4 and evaporated
under vacuum to provide the crude intermediate ((3R,4S,5S,6R)-6-
(hydroxymethyl)-2-methoxy-2-(4-methyl-5-(4-propylbenzyl)thio-
phen-2-yl)tetrahydro-2H-pyran-3,4,5-triol) (50), which was used
without further purification. MS calcd for C22H30O6S (MW 422.54),
found [MꢀOMe]+ 391.
4.2.59. Synthesis of 5-Bromo-3-methyl-2-(4-propylbenzyl)-
thiophene (46)
To a solution of (5-bromo-3-methylthiophen-2-yl)(4-propyl-
phenyl)methanone (45, 0.95 g, 2.95 mmol) in DCM (9.4 mL) and
ACN (9.4 mL) was added triethylsilane (1.42 mL, 8.85 mmol) fol-
lowed by BF3 etherate (1.11 mL, 8.85 mmol) under nitrogen atmo-
sphere at 0 °C. The reaction mixture was allowed warmed to
room temperature and stirred for 16 h. The mixture was poured
into a saturated K2CO3 solution (50 mL) and extracted with EtOAc
(100 mL). The organic phase was dried over MgSO4 and evapo-
rated under vacuum. The residue was further purified by silica
column chromatography (BiotageÒ) to provide 5-bromo-3-
methyl-2-(4-propylbenzyl)thiophene (46, 0.86 g, 2.77 mmol,
94%). 1H NMR (400 MHz, CDCl3) d 7.10 (s, 4H), 6.75 (s, 1H),
3.95 (s, 2H), 2.55 (t, J = 7.6 Hz, 2H), 2.12 (s, 3H), 1.67–1.57 (m,
2H), 0.93 (t, J = 7.6 Hz, 3H); MS calcd for
C15H17BrS (MW
309.26), found [M+H]+ 309.
4.2.60. Synthesis of 5-Iodo-3-methyl-2-(4-propylbenzyl)-
thiophene (47)
Step 3: To a solution of crude (3R,4S,5S,6R)-6-(hydroxymethyl)-
2-methoxy-2-(4-methyl-5-(4-propylbenzyl)thiophen-2-yl)tetra-
hydro-2H-pyran-3,4,5-triol (50) in DCM (11.8 mL) and ACN
(11.8 mL) was added triethylsilane (0.786 mL, 4.90 mmol) followed
by BF3 etherate (0.611 mL, 4.90 mmol) under nitrogen atmosphere
at ꢀ60 °C. The reaction temperature was maintained ꢀ60 and
ꢀ30 °C for 2 h. The reaction was quenched with a saturated NaH-
CO3 solution (20 mL), and then extracted with EtOAc (50 mL).
The organic phase was dried over MgSO4 and evaporated under
vacuum. The residue was further purified by prep HPLC (C18) to
provide the title compound 51 (391 mg, 0.996 mmol, 37%). 1H
NMR (400 MHz, CD3OD) d 6.97 (s, 4H), 6.73 (s, 1H), 4.19 (d,
J = 9.6 Hz, 1H), 3.89 (s, 2H), 3.75 (d, J = 10.0 Hz, 1H), 3.57–3.51
(m, 1H), 3.33–3.24 (m, 4H), 2.44 (t, J = 7.6 Hz, 2H), 2.03 (s, 3H),
1.54–1.46 (m, 2H), 0.82 (t, J = 7.2 Hz, 3H); MS calcd for C20H26O5S
(MW 391.51), found [MꢀOH]+ 375.
To
a mixture of 5-bromo-3-methyl-2-(4-propylbenzyl)thio-
phene (46, 0.86 g, 2.77 mmol), sodium iodide (0.83 g, 5.53 mmol)
and copper(I) iodide (0.053 g, 0.277 mmol) in dioxane (5.2 mL)
was added N,N0-dimethylethylenediamine (0.060 mL, 0.553 mmol).
The resulting mixture was heated to 110 °C and stirred for 16 h.
After cooling to room temperature, the reaction mixture was fil-
tered through a plug of CeliteÒ and then washed with EtOAc
(50 mL). The filtrate was washed with brine and dried over MgSO4.
The organic phase was evaporated under vacuum to provide 5-
iodo-3-methyl-2-(4-propylbenzyl)thiophene (0.95 g, 2.66 mmol,
96%) as a yellow oil, which was used without further purification.
MS calcd for C15H17IS (MW 356.26), found [M]+ 356.
4.2.61. Synthesis of (4-ethoxyphenyl)(3-methylthiophen-2-yl)-
methanone (44, via route b)
To a solution of 4-bromophenetole (1.86 mL, 13.0 mmol) in
anhydrous THF (15 mL) was added dropwise (over a 5-min period)
a solution of n-BuLi (6.0 mL, 2.5 M in hexane) under nitrogen atmo-
sphere at ꢀ78 °C. The resulting mixture was stirred at ꢀ78 °C for
1 h, and then a solution of the Weinreb amide 43 (1.85 g,
10.0 mmol) in anhydrous THF (5.0 mL) was added dropwise (over
a 10-min period). The reaction mixture was allowed to warm to
room temperature and stirred for 16 h. The mixture was poured
4.2.63. (2R,3R,4S,5S,6R)-2-(5-(4-Ethoxybenzyl)-4-methyl-
thiophen-2-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-
triol (72a)
1H NMR (400 MHz, CD3OD) d 7.18 (d, J = 8.8 Hz, 2H), 6.92 (s,
1H), 6.90 (d, J = 8.8 Hz, 2H), 4.38 (d, J = 9.6 Hz, 1H), 4.09 (q,
J = 7.2 Hz, 2H), 4.05 (s, 2H), 3.95 (d, J = 11.6 Hz, 1H), 3.76–
3.71 (m, 1H), 3.53–3.42 (m, 4H), 2.22 (s, 3H), 1.45 (t,
J = 7.2 Hz, 3H); MS calcd for C20H26O6S (MW 394.48), found
[MꢀOH]+ 377.
into
a 1 M HCl solution (25 mL) and extracted with EtOAc
(50 mL). The organic phase was subsequently washed with brine,
dried over MgSO4 and evaporated under vacuum. The residue
was further purified by silica column chromatography (BiotageÒ)
to provide (4-ethoxyphenyl)(3-methylthiophen-2-yl)methanone
(44, 1.52 g, 6.16 mmol, 62%). 1H NMR (400 MHz, CDCl3) d 7.84 (d,
J = 8.8 Hz, 2H), 7.45 (d, J = 5.2 Hz, 1H), 7.98 (d, J = 4.8 Hz, 1H),
6.94 (d, J = 9.2 Hz, 2H), 4.11 (q, J = 6.8 Hz, 2H), 2.40 (s, 3H), 1.45
(t, J = 6.8 Hz, 3H); MS calcd for C14H14O2S (MW 246.32), found
[M+H]+ 247.
4.2.64. (2R,3S,4S,5R,6R)-2-(Hydroxymethyl)-6-(5-(4-methoxy-
benzyl)-4-methylthiophen-2-yl)tetrahydro-2H-pyran-3,4,5-triol
(72b)
1H NMR (400 MHz, CD3OD) d 7.08 (d, J = 8.8 Hz, 2H), 6.81 (s,
1H), 6.79 (d, J = 8.8 Hz, 2H), 4.26 (d, J = 9.6 Hz, 1H), 3.93 (s, 2H),
3.83 (d, J = 11.6 Hz, 1H), 3.73 (s, 3H), 3.63–3.59 (m, 1H), 3.41–
3.30 (m, 4H), 2.10 (s, 3H); MS calcd for C19H24O6S (MW 380.46),
found [MꢀOH]+ 363.

5830
S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
4.2.65. (2R,3R,4S,5S,6R)-2-(5-(4-Chlorobenzyl)-4-methylthio-
phen-2-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol
(72c)
The reaction mixture was quenched by adding saturated Na2S2O3
solution (20 mL) and extracted with EtOAc (2 ꢁ 50 mL). The organ-
ic layer was washed with brine and dried over MgSO4, filtered, and
concentrated in vacuo. The crude residue was purified on BiotageÒ
purification apparatus to yield the title compound (4.28 g,
10.6 mmol, 55%) as a yellow solid.
1H NMR (400 MHz, CD3OD) d 7.23 (d, J = 8.8 Hz, 2H), 7.15 (d,
J = 8.8 Hz, 2H), 6.82 (s, 1H), 4.27 (d, J = 9.6 Hz, 1H), 4.00 (s, 2H),
3.83 (d, J = 12.0 Hz, 1H), 3.62–3.59 (m, 1H), 3.39–3.30 (m, 4H),
2.10 (s, 3H); MS calcd for C18H21ClO5S (MW 384.87), found
[MꢀOH]+ 367.
1H NMR (400 MHz, CDCl3) 7.72 (dd, J = 6.4, 2.0 Hz, 2H), 7.31 (dd,
J = 6.4, 2.0 Hz, 2H), 2.74 (q, J = 7.6 Hz, 2H), 2.45 (s, 3H), 1.28 (t,
J = 7.6 Hz, 3H); MS calcd for C14H12Br2OS (MW 388.12), found
[M+H]+ 387.
4.2.66. (2R,3R,4S,5S,6R)-2-(5-(4-tert-Butylbenzyl)-4-methylthio-
phen-2-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol
(72d)
4.2.70.3. Step 3: 2,3-Dibromo-5-(4-ethylbenzyl)-4-methylthi-
ophene (55). To a solution of (4,5-dibromo-3-methylthiophen-
2-yl)(4-ethylphenyl)methanone (54) (4.28 g, 10.6 mmol) in DCM/
CH3CN (30:30 mL) were added triethylsilane (5.1 mL, 31.9 mmol)
and borontrifluoride diethyletherate (3.1 mL, 25.4 mmol) at 0 °C.
The resulting solution was stirred at ambient temperature over-
night. The reaction mixture was quenched by adding MeOH
(10 mL) and concentrated in vacuo. The crude residue was purified
on BiotageÒ purification apparatus to yield the title compound
(3.65 g, 9.76 mmol, 92%) as yellow oil.
1H NMR (400 MHz, CD3OD) d 7.27 (d, J = 8.4 Hz, 2H), 7.09 (d,
J = 8.4 Hz, 2H), 6.80 (s, 1H), 4.26 (d, J = 9.2 Hz, 1H), 3.96 (s, 2H),
3.83 (d, J = 12.0 Hz, 1H), 3.63–3.59 (m, 1H), 3.39–3.32 (m, 4H),
2.12 (s, 3H), 1.27 (s, 9H); MS calcd for C22H30O5S (MW 406.54),
found [MꢀOH]+ 389.
4.2.67. (2R,3S,4S,5R,6R)-2-(Hydroxymethyl)-6-(4-methyl-5-(4-
methylbenzyl)thiophen-2-yl)tetrahydro-2H-pyran-3,4,5-triol
(72e)
1H NMR (400 MHz, CD3OD) d 7.04 (s, 4H), 6.80 (s, 1H), 4.26 (d,
J = 9.6 Hz, 1H), 3.95 (s, 2H), 3.83 (d, J = 11.6 Hz, 1H), 3.63–3.59
(m, 1H), 3.41–3.30 (m, 4H), 2.26 (s, 3H), 2.10 (s, 3H); MS calcd
for C19H24O5S (MW 364.46), found [MꢀOH]+ 347.
1H NMR (400 MHz, CDCl3) 7.12 (ABq,
DmAB = 18.2 Hz,
JAB = 8.4 Hz, 4H), 4.00 (s, 2H), 2.63 (q, J = 7.6 Hz, 2H), 2.19 (s, 3H),
1.22 (t, J = 7.6 Hz, 3H).
4.2.70.4. Step 4:
(2R,3R,4S,5R,6R)-2-(Acetoxymethyl)-6-(3-
bromo-5-(4-ethylbenzyl)-4-methylthiophen-2-yl)-tetrahydro-
2H-pyran-3,4,5-triyl triacetate (56). To a solution of 2,3-dibro-
mo-5-(4-ethylbenzyl)-4-methylthiophene (55) (3.65 g, 9.76 mmol)
and (3R,4S,5R,6R)-3,4,5-tris(trimethylsilyloxy)-6-((tirmethylsilyl-
oxy)methyl)-tetrahydropyran-2-one (5.01 g, 10.7 mmol) in THF
(50 mL) was added (trimethylsilyl)methyllithium (1 M solution in
pentane, 20 mL, 19.5 mmol) at ꢀ50 °C. The resulting solution was
stirred at ꢀ50 to ꢀ40 °C for 2 h. After addition of saturated NaHCO3
solution (20 mL), the mixture was extracted with EtOAc
(3 ꢁ 30 mL). The organic layer was washed with brine, dried over
MgSO4, filtered, and concentrated in vacuo. The crude residue
was dissolved in THF (30 mL) and cooled to ꢀ78 °C. To this solution
was added a solution of methanesulfonic acid (1.5 mL, 23.4 mmol)
in MeOH at ꢀ78 °C. The resulting mixture was warmed to ꢀ50 °C
over a period of 2 h. and then saturated NaHCO3 solution (30 mL)
was added to the solution. After extraction of the reaction mixture
with EtOAc (50 mL ꢁ 3), the organic layer was washed with brine,
dried over MgSO4, filtered, and concentrated in vacuo. The crude
residue was dissolved in DCM/CH3CN (20:20 mL) and cooled to
ꢀ60 °C. To this solution were added triethylsilane (3.5 mL,
22.2 mmol) and borontrifluoride diethyletherate (2.2 mL,
17.7 mmol). The resulting mixture was warmed to ꢀ30 °C over a
period of 2 h. and then saturated NaHCO3 solution (20 mL) was
added to the solution. After extraction of the reaction mixture with
EtOAc (50 mL ꢁ 3), the organic layer was washed with brine, dried
over MgSO4, filtered, and concentrated in vacuo. The crude residue
was dissolved in DCM (20 mL). To this solution were added
dimethylaminopyridine (106 mg, 0.870 mmol), pyridine (4.2 mL,
52.2 mmol), and acetic anhydride (4.1 mL, 43.5 mmol). The result-
ing mixture was stirred at ambient temperature overnight and
then water (30 mL) was added to the solution. After extraction of
the reaction mixture with EtOAc (50 mL ꢁ 2), the organic layer
was washed with brine, dried over MgSO4, filtered, and concen-
trated in vacuo. The crude residue was purified on BiotageÒ purifi-
cation apparatus to yield the title compound (1.22 g, 1.95 mmol,
20%) as a yellow solid.
4.2.68. (2R,3R,4S,5S,6R)-2-(5-(4-Ethylbenzyl)-4-methylthiophen-
2-yl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (72f)
1H NMR (400 MHz, CD3OD) d 7.07 (s, 4H), 6.80 (s, 1H), 4.26 (d,
J = 9.2 Hz, 1H), 3.96 (s, 2H), 3.83 (d, J = 12.0 Hz, 1H), 3.63–3.59
(m, 1H), 3.41–3.32 (m, 4H), 2.57 (q, J = 7.6 Hz, 2H), 2.11 (s, 3H),
1.18 (t, J = 7.6 Hz, 3H); MS calcd for C20H26O5S (MW 378.48), found
[MꢀOH]+ 361.
4.2.69. (2R,3S,4S,5R,6R)-2-(Hydroxymethyl)-6-(4-methyl-5-(4-
propylbenzyl)thiophen-2-yl)tetrahydro-2H-pyran-3,4,5-triol
(72g)
1H NMR (400 MHz, CD3OD) d 6.97 (s, 4H), 6.73 (s, 1H), 4.19 (d,
J = 9.6 Hz, 1H), 3.89 (s, 2H), 3.75 (d, J = 10.0 Hz, 1H), 3.57–3.51
(m, 1H), 3.33–3.24 (m, 4H), 2.44 (t, J = 7.6 Hz, 2H), 2.03 (s, 3H),
1.54–1.46 (m, 2H), 0.82 (t, J = 7.2 Hz, 3H); MS calcd for C21H28O5S
(MW 392.51), found [MꢀOH]+ 375.
4.2.70. Synthesis of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(3-
bromo-5-(4-ethylbenzyl)-4-methylthiophen-2-yl)-tetrahydro-
2H-pyran-3,4,5-triyl triacetate (56)
4.2.70.1. Step 1: (4-Ethylphenyl)(3-methylthiophen-2-yl)meth-
anone (53). To a solution of N-methoxy-N,3-dimethylthiophene-
2-carboxamide (52) (J. Med. Chem., 2001, 44, 863) (5.00 g,
27.0 mmol) in THF (30 mL) was added 4-ethylphenylmagnesium
bromide (0.5 M in THF, 108 mL, 54.0 mmol) at 0 °C. The resulting
solution was stirred at ambient temperature overnight. The reac-
tion mixture was quenched by adding MeOH (20 mL) and concen-
trated in vacuo. The crude residue was purified on BiotageÒ
purification apparatus to yield the title compound (4.42 g,
19.2 mmol, 71%) as brown oil.
1H NMR (400 MHz, CDCl3) 7.77 (dd, J = 6.4, 2.0 Hz, 2H), 7.47 (d,
J = 4.8 Hz, 1H), 7.29 (dd, J = 8.0, 0.4 Hz, 2H), 7.00 (dd, J = 4.8, 0.4 Hz,
1H), 2.73 (q, J = 7.6 Hz, 2H), 2.48 (s, 3H), 1.28 (t, J = 7.6 Hz, 3H).
4.2.70.2. Step 2: (4,5-Dibromo-3-methylthiophen-2-yl)(4-ethyl-
phenyl)methanone (54). To a solution of (4-ethylphenyl)(3-
methylthiophen-2-yl)methanone (53) (4.42 g, 19.2 mmol) in AcOH
(30 mL) was added bromine (3.9 mL, 76.8 mmol) slowly. The
resulting solution was stirred at ambient temperature overnight.
1H NMR (400 MHz, CDCl3) 7.10 (ABq,
DmAB = 20.8 Hz,
JAB = 8.4 Hz, 4H), 5.33 (t, J = 7.2 Hz, 1H), 5.20–5.13 (m, 2H), 4.88
(d, J = 10.0 Hz, 1H), 4.23–4.13 (m, 2H), 4.02 (d, J = 3.2 Hz, 2H),
3.86–3.81 (m, 1H), 2.62 (q, J = 7.6 Hz, 2H), 2.11 (s, 3H), 2.07 (s,

S. H. Lee et al. / Bioorg. Med. Chem. 19 (2011) 5813–5832
5831
3H), 2.04 (s, 3H), 2.00 (s, 3H), 1.90 (s, 3H), 1.22 (t, J = 7.6 Hz, 3H);
2.0 Hz, 1H), 3.62 (dd, J = 12.0, 6.0 Hz, 1H), 3.45–3.35 (m, 4H), 2.59
(q, J = 7.6 Hz, 2H), 2.12 (s, 3H), 2.05 (s, 3H), 1.19 (t, J = 7.6 Hz,
3H); MS calcd for C21H28O5S (MW 392.51), found [M+Na]+ 415.
MS calcd for C28H33BrO9S (MW 625.53), found [M+Na]+ 647.
4.2.71. Synthesis of (2R,3R,4S,5S,6R)-2-(3-bromo-5-(4-ethyl-
benzyl)-4-methylthiophen-2-yl)-6-(hydroxymethyl)tetrahydro-
2H-pyran-3,4,5-triol (72h)
4.3. In vitro assay
To a suspension of acetate (56) (200 mg, 0.320 mmol) in MeOH
(5 mL) was added NaOMe (25 wt % in MeOH, 0.1 mL) at room tem-
perature. The mixture was stirred at room temperature for 1 h.
Glacial AcOH was added to the mixture to acidify the mixture.
The mixture was concentrated under reduced pressure. The resi-
due was purified by prep HPLC (C18) to provide the title compound
71h (80 mg, 55%). 1H NMR (400 MHz, CD3OD3) d 7.10 (s, 4H), 4.60
(d, J = 9.2 Hz, 1H), 4.04 (d, J = 3.2 Hz, 2H), 3.86–3.80 (m, 1H), 3.63–
3.58 (m, 1H), 3.44–3.40 (m, 2H), 3.39–3.32 (m, 2H), 2.58 (q,
J = 7.6 Hz, 2H), 2.14 (s, 3H), 1.18 (t, J = 7.6 Hz, 3H); MS calcd for
4.3.1. Cloning and cell line construction for human SGLT2
Human SGLT2 (hSGLT2) gene was amplified by PCR from cDNA-
Human Adult Normal Tissue Kidney (Invitrogen, Carlsbad, CA). The
hSGLT2 sequence was cloned into pcDNA3.1(+) for mammalian
expression and were stably transfected into Chinese hamster ovary
(CHO) cells. SGLT2-expressing clones were selected based on resis-
tance to G418 antibiotic (GeneticinÒ, Invitrogen, Carlsbad, CA) and
activity in the 14C-
assay.
a-methyl-D
-glucopyranoside (14C-AMG) uptake
C
20H25BrO5S (MW 457.38), found [MꢀOH]+ 441.
4.3.2. Inhibitory effects on human SGLT2 activities
For sodium-dependent glucose transport assay, cells expressing
hSGLT2 were seeded into a 96-well culture plate at a density of
5 ꢁ 104 cells/well in RPMI medium 1640 containing 10% fetal bo-
vine serum. The cells were used 1 day after plating. They were
incubated in pretreatment buffer (10 mM HEPES, 5 mM Tris,
140 mM choline chloride, 2 mM KCl, 1 mM CaCl2, and 1 mM MgCl2,
pH 7.4) at 37 °C for 10 min. They were then incubated in uptake
buffer (10 mM HEPES, 5 mM Tris, 140 mM NaCl, 2 mM KCl, 1 mM
CaCl2, 1 mM MgCl2, and 1 mM 14C-nonlabeled AMG pH 7.4) con-
4.2.72. Synthesis of (2R,3R,4S,5S,6R)-2-(5-(4-ethylbenzyl)-3-
methoxy-4-methylthiophen-2-yl)-6-(hydroxymethyl)-
tetrahydro-2H-pyran-3,4,5-triol (72i)
To a solution of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(3-bro-
mo-5-(4-ethylbenzyl)-4-methylthiophen-2-yl)-tetrahydro-2H-
pyran-3,4,5-triyl triacetate (56) (200 mg, 0.320 mmol) in NaOMe
(25wt% in MeOH, 10 mL, 43.2 mmol) were added cupric oxide
(25.5 mg, 0.320 mmol) and KI (53.1 mg, 0.320 mmol). The resulting
solution was stirred at 120 °C overnight. The reaction mixture was
filtered through celiteÒ bed and concentrated in vacuo. The crude
residue was purified on reverse phase preparative HPLC to yield
the title compound (24.3 mg, 0.0595 mmol, 19%) as a yellow solid.
1H NMR (400 MHz, MeOD) 7.11–7.09 (m, 4H), 4.52 (dd, J = 6.4,
taining 14C-labeled (8
lM) and inhibitor or dimethyl sulfoxide
(DMSO) vehicle at 37 °C for 2 h. Cells were washed twice with
washing buffer (pretreatment buffer containing 10 mM AMG at
room temperature) and then the radioactivity was measured using
a liquid scintillation counter. IC50 was determined by nonlinear
21,22
2.4 Hz, 1H), 3.96 (ABq,
D
m
AB = 14.0 Hz, JAB = 16.0 Hz, 2H), 3.84
regression analysis using GraphPad PRISM.
(dd, J = 12.0, 2.0 Hz, 1H), 3.79 (s, 3H), 3.60 (dd, J = 12.0, 6.0 Hz,
1H), 3.43 (dd, J = 6.4, 2.4 Hz, 2H), 3.39–3.35 (m, 2H), 2.60 (q,
J = 7.6 Hz, 2H), 2.04 (s, 3H), 1.20 (t, J = 7.6 Hz, 3H); MS calcd for
Acknowledgments
C
21H28O6S (MW 408.51), found [M+Na]+ 431.
This paper is dedicated to Professor Eun Lee on the occasion of
his retirement from Seoul National University in August 2011. We
appreciate Dr. Eun Chul Huh for his leadership and supports as
Head of GCC R&D.
4.2.73. Synthesis of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(5-(4-
ethylbenzyl)-3,4-dimethylthiophen-2-yl)-tetrahydro-2H-pyran-
3,4,5-triyl triacetate (57)
To a solution of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(3-bro-
mo-5-(4-ethylbenzyl)-4-methylthiophen-2-yl)-tetrahydro-2H-
pyran-3,4,5-triyl triacetate (56) (200 mg, 0.320 mmol) in toluene/
References and notes
1. International Diabetes Federation Diabetes Atlas, 3rd ed.; International Diabetes
Federation: Brussels, Belgium, 2006.
water (4:2 mL) were added trimethylboroxine (134 lL,
0.960 mmol), Pd(OAc)2 (7.2 mg, 0.0320 mmol), tricylcohexylphos-
phine tetrafluoroborate (23.6 mg, 0.0640 mmol), and K3PO4
(272 mg, 1.28 mmol). The mixture was stirred at 100 °C overnight.
The reaction mixture was filtered through celite bed and concen-
trated in vacuo. The crude residue was purified on BiotageÒ purifi-
cation apparatus to yield the title compound (125 mg, 0.223 mmol,
70%) as a yellow solid. MS calcd for C29H36O9S (MW 560.66), found
[M+Na]+ 583.
2. American Diabetes Association Diabetes Care 2004, 27, S5–S10.
3. Dwarakanathan, A. J. Insur. Med. 2006, 38, 20–30.
4. Mackenzie, B.; Loo, D. D. J. Biol. Chem. 1996, 20, 32678–32683.
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T. J. Cell Biochem. 2003, 90, 339–346.
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Pullockaran, A.; Hagan, D. L.; Morgan, N.; Taylor, J. R.; Obermeier, M. T.;
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4.2.74. Synthesis of (2R,3R,4S,5S,6R)-2-(5-(4-ethylbenzyl)-3,4-
dimethylthiophen-2-yl)-6-(hydroxymethyl)-tetrahydro-2H-
pyran-3,4,5-triol (72j)
To a solution of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(5-(4-
ethylbenzyl)-3,4-dimethylthiophen-2-yl)-tetrahydro-2H-pyran-
3,4,5-triyl triacetate (57) (125 mg, 0.223 mmol) in MeOH (5 mL)
was added NaOMe (25 wt % in MeOH, 310 lL, 1.34 mmol). The
reaction mixture was stirred at ambient temperature for 2 h before
AcOH (2 mL) was added. Purification by reverse phase preparative
HPLC provided the title compound (24.8 mg, 0.0632 mmol, 28%) as
a brown solid.
12. Washburn, W. N. J. Med. Chem. 2009, 52, 1785–1794.
13. (a) Nomura, S.; Sakamaki, S.; Hongu, M.; Kawanski, E.; Koga, Y.; Sakamoto, T.;
Yamamoto, Y.; Ueta, K.; Kimata, H.; Nakayama, K.; Tsuda-Tsukimoto, M.
Presented at the 238th American Chemical Society National Meeting and
Exposition, Washington, DC, August 16–20, 2009; Medi-151.; (b) Nomura, S.;
Sakamaki, S.; Hongu, M.; Kawanshi, E.; Koga, Y.; Sakamoto, T.; Yamamoto, Y.;
1H NMR (400 MHz, MeOD) 7.08 (s, 4H), 4.50 (d, J = 9.2 Hz, 1H),
3.99 (ABq,
DmAB = 10.4 Hz, JAB = 16.0 Hz, 2H), 3.84 (dd, J = 12.0,

5832
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