Synthesis and biological evaluation of (±)-3-(2-(2-fluorobenzyloxy) naphthalen-6-yl)-2-aminopropanoic acid derivatives as novel PTP1B inhibitors

Article abstract of DOI:10.1016/j.ejmech.2011.05.027

A series of novel nonphosphonate-based pTyr mimetics comprised (±)-3-(2-(2-fluorobenzyloxy)naphthalen-6-yl)-2-aminopropanoic acid derivatives were identified as reversible and competitive PTP1B inhibitors via a structure-based design approach. Among the c

Full text of DOI:10.1016/j.ejmech.2011.05.027

European Journal of Medicinal Chemistry 46 (2011) 3630e3638
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and biological evaluation of (ꢀ)-3-(2-(2-fluorobenzyloxy)
naphthalen-6-yl)-2-aminopropanoic acid derivatives as novel PTP1B inhibitors
Liang-Peng Sun a, Qiang Shen b, Hong-Hua Piao a, Wei-Ping Ma b, Li-Xin Gao b, Wei Zhang b, Fa-Jun Nan b,
**
,
a,
*
Jia Li b , Hu-Ri Piao
a Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules, Ministry of Education, Yanbian University College of Pharmacy, Yanji 133000, PR China
b National Center for Drug Screening, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 201203, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel nonphosphonate-based pTyr mimetics comprised (ꢀ)-3-(2-(2-fluorobenzyloxy)naph-
thalen-6-yl)-2-aminopropanoic acid derivatives were identified as reversible and competitive PTP1B
inhibitors via a structure-based design approach. Among the compounds studied, 12h was found to have
Received 23 September 2010
Received in revised form
11 May 2011
Accepted 13 May 2011
Available online 20 May 2011
the best in vitro inhibition activity against PTP1B (IC50 ¼ 1.25 ꢀ 0.24
mM) and the best selectivity (3-fold)
between PTP1B and TCPTP. These results should provide suitable druglike lead compounds for the design
of inhibitors of PTP1B as well as other PTPs.
Ó 2011 Elsevier Masson SAS. All rights reserved.
Keywords:
Protein tyrosine phosphatase 1B
Inhibitors
2-Naphthol tyrosine
SAR
Diabetes
1. Introduction
have considerable therapeutic potential for the treatment of Type II
diabetes and obesity.
Protein tyrosine phosphatases (PTPs) constitute a large family of
signaling enzymes that control several fundamental cellular func-
tions via phosphorylation and dephosphorylation reactions [1e5].
Deregulation of PTP activity can play a role in a number of diseases
including diabetes, cancer, and dysfunction of the immune system
[6e8]. Among PTPs, protein tyrosine phosphatase 1B (PTP1B) has
received much attention due to its pivotal role in type II diabetes
and obesity as a negative regulator of the insulin and leptin-
signaling pathway [9e11]. Studies from two laboratories have
shown that PTP1B knockout mice exhibit phenotypes of increased
insulin sensitivity, improved glucose tolerance, and resistance to
diet-induced obesity [12,13]. In a more therapeutically relevant
study, Zinker et al. have demonstrated that a PTP1B antisense
oligonucleotide normalizes blood glucose and improves insulin
sensitivity in diabetic mice via a mechanism of lowering PTP1B
protein expression [14e17]. Thus, small molecule PTP1B inhibitors
Recent studies have provided important insights into the basic
structural requirements for PTP1B-substrate and -inhibitor inter-
actions and have suggested that identification of highly selective,
catalytic site-directed PTP1B inhibitors is possible. Disappointingly,
nearly all medicinal chemistry efforts to date have been severely
hindered because of the lack of suitable druglike lead compounds
for optimization to drug candidates. As is well documented in the
literature, the majority of competitive inhibitors of PTP1B incor-
porate highly charged anions that mimic the pTyr substrate I, such
as difluoromethylphosphonates (DFMP) II and V, carboxymethyl-
salicyclic acids (CMS) III and VI, and oxalylaminobenzoic acids
(OBA) IV (Fig. 1) [18,19]. Compounds containing negatively-charged
non-hydrolyzable pTyr mimetics have exhibited excellent potency
(at nanomolar concentrations) in vitro, however, the low cell
permeability and low bioavailability of these compounds have
limited their application for the development of effective drugs
[20e22]. Therefore, we sought a new pTyr mimetic that would not
only be a potent inhibitor of PTP1B, but one which would also avoid
or minimize the polarity.
Because of the electrostatic properties of the enzyme active site
[23], it has proven difficult to develop effective uncharged pTyr
mimetics. A useful and commonly adopted strategy in the design of
PTP1B inhibitors is to insert nonhydrolyzable pTyr-mimetic groups
* Corresponding author. Tel.: þ86 433 2660503; fax: þ86 433 2659795.
** Corresponding author. Tel.: þ86 21 50800721; fax: þ86 21 50800721.
E-mail addresses: jli@mail.shcnc.ac.cn (J. Li), piaohuri@yahoo.com.cn
(H.-R. Piao).
0223-5234/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2011.05.027

L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
3631
Fig. 1. Structures of some known pTyr mimetics.
that are able to replicate the interactions of pTyr residue with the
active site of the enzyme onto different optimal templates [24e27].
Replacing the phosphate group of pTyr with bioisosteric mono-
anionic groups, such as carboxylates, is considered a valid method to
obtain inhibitors with low polarity [24,28]. The objective of our
PTP1B inhibitor program was to identify a novel series of selective
and reversible inhibitors of PTP, employing a monoanionic and
a non-peptidyl small molecule. Based on the above analysis, we
assumed that desired druglike lead compounds could be obtained if
the monoacid based fragment was reserved and the phosphate
group of pTyr was effectively replaced by hydrophobic groups
(Fig. 2), in which the carboxylic group mimics the interactions of the
phosphate group of pTyr with residues in the PTP1B catalytic site
and hydrophobic groups improve the stability of the enzyme/
inhibitor complex through hydrophobic interactions with the active
site and surrounding subpockets [27e29]. As a starting point toward
this goal, we have utilized structure-based design methods to design
and synthesize 2-naphthol tyrosine analogs, and identified
(ꢀ)- 3-(2-(2-fluorobenzyloxy)naphthalen-6-yl)-2-aminopropanoic
acid (10) (Fig. 2) as a potential PTP1B inhibitor with an IC50 value
of 24.73 ꢀ 2.05
mM. In addition, the further results showed that
introducing acyl groups at the N-terminus could increase the
activity. Therefore, we decided to keep the hydrophobic group fixed
as the 2-fluorobenzyl group and then investigate the relationship
between various acyl groups and PTP1B inhibitoryactivity (Fig. 2). In
this report, we provide the design, synthesis, and primary struc-
tureeactivity relationships of this novel class of PTP1B inhibitors.
2. Chemistry
The synthetic pathways are illustrated in Schemes 1 and 2. (ꢀ)-2-
(Benzamido)-3-(2-hydroxynaphthalen-6-yl)propanoic acid
1 or
(ꢀ)-2-amino-3-(2-hydroxynaphthalen-6-yl)propanoic acid 3 were
synthesized starting from 6-hydroxynaphthalene-2-carbalde-hyde
as described previously in Ref. [30]. Compounds 2aec were
synthesized as shown in Scheme 1 and were obtained in high yield
COOH
HO
OH
COOH
P
NH2
O
O
NH2
hydrophobic
moiety
monoacid
moiety
Link moiety
PTry
COOH
Ar
COOH
F
F
HN
NH2
O
O
O
10 IC50 = 21.69 1.78 µM
12a-r
Fig. 2. Structure-based design of a novel class of PTP1B inhibitors.

3632
L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
COOH
compounds 11aer in good yields. Subsequent saponification with
LiOH in aqueous THF/MeOH provided the desired target compounds
12aer.
COOH
NH
a
NH
O
HO
O
O
R
2a R = 2-F
2b R = 4-OCH3
2c R = 4-Cl
1
3. Results and discussion
The inhibitory activities of all the synthesized compounds
against PTP1B were measured using p-nitrophenyl phosphate
(pNPP) as a substrate, and the results are summarized in Table 1.
Scheme 1. Synthesis of compounds 2aec. Reagents and conditions: (a) substituted
benzyl chlorides, K2CO3, acetone, reflux, 4 h.
The known PTP1B inhibitor, ursolic acid (3.40 ꢀ 0.17
mM), was used
through the nucleophilic substitution reaction of 1 with substituted
benzyl chlorides in refluxing acetone in the presence of potassium
carbonate. Compounds 12aer were synthesized as shown in
Scheme 2. Compound 3 was treated with thionyl chloride in meth-
anol to afford the methyl ester, which was converted directly to the
Boc derivative 5. Compound 7 was prepared by alkylation of the
phenol 5 with 1-(chloromethyl)-2-fluorobenzene, followed by
removal of the protecting Boc group with trifluoroacetic acid to form
the key intermediate 9. Compounds 5, 7 and 9 were saponified with
NaOH in aqueous MeOH to afford compounds 6, 8 and 10, respec-
tively. Amine 9 was coupled with the appropriate acids in the
presence of dicyclohexylcarbodiimide as a condensing agent to give
as the positive control [31].
(ꢀ)-2-Amino-3-(2-hydroxynaphthalen-6-yl)propanoic acid
3
and its benzamide capped analog 1 showed no activity at 300
m
M
concentration, but interestingly, introduction of substituted ben-
zyloxy groups to compound 1 at the 6-position of the naphthalene
ring (2aec) dramatically improved PTP1B inhibitory activity with
IC50 values of 6.55 ꢀ 0.55, 14.28 ꢀ 1.67 and 21.69 ꢀ 1.78
mM,
respectively. Based on these results, it seems that the substituted
benzyloxy group leads to stronger binding. It was thought that the
lipophilic moiety might stabilize the complex with the enzyme
through hydrophobic interactions with the active site and
surrounding subpockets, as this has often been observed in PTP1B/
Scheme 2. Synthesis of compounds 12aer. Reagents and conditions: (a) SOCl2, MeOH, reflux, 3 h; (b) Boc2O, Et3N, MeCN, 25 ꢁC, 3 h; (c)1-(chloromethyl)-2-fluorobenzene, K2CO3,
acetone, reflux, 4 h; (d) TFA, CH2Cl2, 5 h; (e) ArCO2H, DCC, DMAP, DCM, 25 ꢁC; (f) LiOH, MeOH, THF, H2O, 2 h (g) NaOH, MeOH, H2O, 2 h.

L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
3633
Table 1
Inhibitory activity of the synthesized compounds against PTP1B and related PTPs.
Cpds
IC50 (m
M)a
PTP1B
TCPTP
CDC25B
SHP-1
PTPa
LAR
1
2a
2b
2c
>300
ec
e
e
e
e
6.55 ꢀ 0.55
14.28 ꢀ 1.67
21.69 ꢀ 1.78
>300
9.43 ꢀ 1.53
e
19.38 ꢀ 0.01
e
NAb
NA
e
NA
e
e
e
e
e
e
e
6
e
e
e
e
e
8
10
11.07 ꢀ 1.87
24.73 ꢀ 2.05
7.91 ꢀ 0.06
10.80 ꢀ 0.90
11.39 ꢀ 1.14
8.88 ꢀ 0.78
2.49 ꢀ 0.05
2.79 ꢀ 0.05
3.38 ꢀ 0.55
1.25 ꢀ 0.24
4.00 ꢀ 0.27
2.59 ꢀ 0.64
1.77 ꢀ 0.26
1.57 ꢀ 0.22
4.22 ꢀ 0.35
4.71 ꢀ 0.55
8.15 ꢀ 0.98
5.90 ꢀ 0.32
4.45 ꢀ 0.18
6.48 ꢀ 2.24
3.40 ꢀ 0.17
e
e
e
e
e
e
e
e
e
e
12a
12b
12c
12d
12e
12f
12g
12h
12i
12j
12k
12l
12m
12n
12o
12p
12q
12r
UAd
12.86 ꢀ 1.63
17.52 ꢀ 0.33
27.25 ꢀ 1.16
18.88 ꢀ 0.61
3.02 ꢀ 0.20
6.08 ꢀ 0.40
5.96 ꢀ 0.17
3.84 ꢀ 0.22
7.24 ꢀ 0.06
4.33 ꢀ 0.66
4.66 ꢀ 0.66
3.67 ꢀ 0.46
6.11 ꢀ 0.30
15.26 ꢀ 1.03
15.20 ꢀ 0.47
9.21 ꢀ 0.06
9.49 ꢀ 0.84
18.21 ꢀ 1.88
6.70 ꢀ 0.16
8.44 ꢀ 0.93
13.73 ꢀ 1.77
15.18 ꢀ 2.87
14.68 ꢀ 4.09
4.58 ꢀ 0.43
5.13 ꢀ 0.13
6.60 ꢀ 0.36
3.08 ꢀ 0.03
5.35 ꢀ 1.22
2.63 ꢀ 0.22
2.89 ꢀ 0.59
2.49 ꢀ 0.13
8.93 ꢀ 0.02
5.63 ꢀ 0.10
10.74 ꢀ 0.08
14.03 ꢀ 2.21
7.04 ꢀ 0.84
11.64 ꢀ 0.11
e
15.55 ꢀ 2.36
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
e
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
e
NA
NA
NA
9.84 ꢀ 2.44
26.50 ꢀ 5.92
18.50 ꢀ 5.32
2.43 ꢀ 0.12
13.22 ꢀ 0.01
16.34 ꢀ 2.55
10.97 ꢀ 1.97
13.02 ꢀ 4.70
12.50 ꢀ 0.13
10.72 ꢀ 2.37
16.44 ꢀ 1.52
NA
NA
NA
e
a
The pNPP assay. IC50 values were determined by regression analyses and expressed as means ꢀ SD of three replications.
b
c
Not active at 20
Not tested.
Positive control.
mg/mL concentration.
d
inhibitor complexes [27e29]. This was also evident through
a comparison of the IC50 values of compounds 3, 6 and 8.
Compared with compounds 8 and 2a, compound 10 was about
2- to 4-fold less potent against PTP1B due to the lack of the BOC
group. This result suggests that introducing acyl groups may be
beneficial for increasing the inhibitory activity. To further
investigate the structure reactivity relationships, we chose to
investigate the N-terminal side chains keeping the hydrophobic
group fixed as the 2-fluorobenzyl group and replacing the Boc group
with simple substituents. Compared to 2a, increasing the length of
the carbon chain, as in compounds 12c and 12d, resulted in a slight
loss of activity. A similar trend was also observed in compounds 12a
Fig. 3. Characterization of 12h to PTP1B.

3634
L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
and 12b. But interestingly, compound 12d, which had an additional
double bond, exhibited greater potency (IC50 ¼ 8.88 ꢀ 0.78 M) than
its more saturated analog 12c (IC50 ¼ 11.39 ꢀ 1.14 M), indicating
12h was found to be the most potent, with a IC50 value of
1.25 ꢀ 0.24 M.
m
m
m
The data in Table 1 also shows the selectivity profiles of most
compounds against several phosphatases. Homogeneous T-cell
protein tyrosine phosphatase (TCPTP) inhibitory activities were
investigated simultaneously by the same method [30]. Generally
compounds demonstrated a 1- to 3-fold selectivity for PTP1B over
TCPTP. In particular, compound 12h showed a nearly 3-fold selec-
tivity for PTP1B versus TCPTP.
that an unsaturated group can improve the inhibitoryactivity. This is
consistent with results reported previously where the hydrogen
bond donor (CH]CH) in the side chain extending from the
N-terminus likely interacts with the carboxyl group of Asp48 [32].
Based on these observations, various trans-cinnamic acids were
coupled with a 2-amido group to afford compounds 12eer in order
to examine the impact of substituents on the aromatic ring. Inter-
estingly, the introduction of substituted trans-cinnamic acids,
whether containing electron-donating or withdrawing groups,
improved the activity. The compounds with electron-withdrawing
groups on the phenyl ring (12een) showed better activity than
compounds 12oer containing the electron-donating groups. These
results indicated that electron-withdrawing groups contributed
more to the inhibitory activity of PTP1B than the electron-donating
groups. However, the derivatives 12m and 12n, containing two Cl
atoms, did not exhibit better inhibitory activity than derivatives
Besides TCPTP, there are several other critical PTPs negatively
regulating insulin dephosphorylation such as src homology
phosphatase-1 (SHP-1), leukocyte antigen-related phosphatase
(LAR) and protein tyrosine phosphatase
a (PTPa). Cell division cycle
25 homolog B (CDC25B), a dual-specificity phosphatase, is an
attractive potential therapeutic antitumor target for small molecule
intervention due to its central role in controlling malignant cell
proliferation by regulating cyclin dependent kinases and because it
is highly expressed in many human tumors [33]. Thus, we tested
the inhibitory activity of our derivatives on the purified recombi-
with
(IC50 ¼ 1.25 ꢀ 0.24
dichlorated compound 12m (IC50 ¼ 4.22 ꢀ 0.35
M). The impact
of the substituent position on the benzene ring on the efficacy was
not predictable. Among all the compounds prepared, Compound
a
single Cl atom. The 2-chlorinated derivative 12h
M) was 3-fold more potent than the 2,4-
M) and the
nant human enzymes SHP-1, LAR, PTP
shown in Table 1, we concluded that our inhibitors had no visible
activities against receptor-like transmembrane PTP and LAR and
possessed about 2- to 10-fold selectivity for PTP1B over SHP-1. The
compounds demonstrated a 1- to 2-fold selectivity for PTP1B over
CDC25B.
a and CDC25B [34,35]. As
m
m
a
3,4-dichlorated compound 12n (IC50 ¼ 4.71 ꢀ 0.55
m
Fig. 4. Docking result of compound 10 and 12h in the PTP1B catalytic pocket. (A) Binding pose of 10 in PTP1B active site. (B) Key residues in binding site surrounding 10. (C) Binding
pose of 12h in PTP1B active site. (D) Key residues in binding site surrounding 12h.

L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
3635
A kinetic study was performed in order to shed light on the
inhibitory mechanism of compound 12h. As also elucidated in Fig. 3,
12h demonstrated a time-independent inhibition of PTP1B (Fig. 3A),
which showed 12h was a fast-binding inhibitor of PTP1B (Fig. 3A).
The time-independent inhibition of 12h toward PTP1B may also
exclude that 12h is a nonspecific inhibitor, because nonspecific
inhibitors always show time-dependent behavior and steep inhibi-
tion curve [36]. As shown in Fig. 3C, we further determined the
inhibition modality of 12h which inhibited PTP1B with the charac-
teristics typical of a competitive inhibitor, as indicated by increased
Km values and unchanged Vmax values when the inhibitor concen-
trationwas increased. Meanwhile, theresultof theLineweavereBurk
plot confirmed 12h as a competitive inhibitor of PTP1B for inter-
secting at the y-axis of a nest of lines with increased inhibitor
concentration (Fig. 3B). The results indicate that 12h bind the cata-
lytic pocket of PTP1B and behave as a competitor to the substrate.
In order to understand the best inhibition activity of 12h against
PTP1B, a molecular docking analysis of 10 and 12h was carried out
using CDOCKER available with Discovery Studio 2.1 (http://www.
accelrys.com). The X-ray crystal structure of PTP1B was taken from
PDB (1NL9) with 2.40 Å resolution, used for the docking studies.
The preferred coordination modes of 10 and 12h are presented
in Fig. 4. Fragment A of 10 is bound into the active site. The carbonyl
and the hydroxy of the eCOOH shows H-bond interaction with
Lys116 and Glu115, respectively. While eNH2 shows H-bond
interaction with Lys120. Fragment B of 12h is bound into the active
site not only through H-bond interactions of eCOOH, but also
through eCONHe and 2-chlorophenyl. The hydroxy of the eCOOH
shows H-bond interaction with Asn111 and Glu115. The carbonyl
of eCONHe shows two H-bond interactions with Lys116. And the
chlorine of 2-chlorophenyl shows H-bond interaction with Trp179
and Gln266. The additional H-bond interaction of 2-chlorophenyl
correlated well with the significant improvement for PTP1B
inhibitory potency of 12h. Moreover, the lipophilic 2-fluorobenzyl
group of 10 and 12h lies on top of a largely hydrophobic region of
the protein, consisted of Ile219, Met258.
theoretical values and were carried out on a 204Q CHN Rapid
Analyzer (PerkineElmer, USA). The major chemicals were
purchased from SigmaeAldrich and Fluka.
5.1.1. General procedure for synthesis of 2aec
A mixture of 1 (0.34 g, 1.0 mmol), appropriate benzyl chlorides
(1.2 mmol), and sodium carbonate anhydrous in refluxing acetone
was stirred for 4 h. The solvent was evaporated under reduced
pressure and the residue was dissolved in dichloromethane, washed
with water and brine, dried over anhydrous MgSO4, and the solvent
was removed under reduced pressure. The resulting residue was
purified by silica gel column chromatography (dichloromethane/
methanol, 20:1 v/v). The yield, melting point and spectral data of
each compound are given below.
5.1.1.1. (ꢀ)-3-(2-(2-Fluorobenzyloxy)naphthalen-6-yl)-2-(benzamido)
propanoic acid (2a). Yield 77%; m.p.167e169 ꢁC. IR (KBr) cmꢂ1: 3445
(NH),1682(C]O), 1665 (C]O). 1H NMR (DMSOed6, 300 MHz, ppm):
d
3.17e3.37 (m, 2H, CH2), 4.68e4.76 (m, 1H, CH), 5.22 (s, 2H, CH2),
7.17e7.80(m,15H, AreH).13CNMR(DMSOed6, 75MHz, ppm):
d
174.0,
166.4, 159.7, 157.3, 134.2, 134.0, 133.7, 131.9, 130.5, 130.0, 129.4, 129.3,
129.0, 128.8, 128.7, 128.1, 128.0, 127.4, 127.3, 127.0, 119.8, 119.5, 107.8,
107.6, 66.8, 54.6, 36.6. MS m/z 444 (M þ 1).
5.1.1.2. (ꢀ)-3-(2-(4-Chlorobenzyloxy)naphthalen-6-yl)-2-(benzamido)
propanoic acid (2b). Yield 73%; m.p.171e163 ꢁC. IR (KBr) cmꢂ1: 3441
(NH), 1694(C]O), 1678 (C]O). 1H NMR (DMSOed6, 300 MHz, ppm):
d
3.16e3.32 (m, 2H, CH2), 4.66e4.74 (m, 1H, CH), 5.19 (s, 2H, CH2),
7.18e7.79(m,15H, AreH).13CNMR(DMSOed6, 75MHz,ppm):
d
173.6,
166.8, 156.2, 136.4, 134.4, 134.0, 133.3, 132.8, 131.7, 130.0, 129.9, 129.8,
129.4, 129.0, 128.9, 128.7, 128.5, 127.7, 127.0, 119.2, 119.0, 107.7, 107.5,
68.8, 55.3, 54.8, 36.8. MS m/z 461 (M þ 1).
5.1.1.3. (ꢀ)-3-(2-(4-Methoxybenzyloxy)naphthalen-6-yl)-2-(benza-
mido)propanoic acid (2c). Yield 69%; m.p. 177e179 ꢁC. IR (KBr)
cmꢂ1:3455 (NH), 1690(C]O), 1678 (C]O). 1H NMR (DMSOed6,
300 MHz, ppm):
4.68e4.74 (m, 1H, CH), 5.10 (s, 2H, CH2), 6.94e7.81 (m, 15H, AreH).
13C NMR (DMSOed6, 75 MHz, ppm):
173.6, 166.8, 159.4, 156.5,
d 3.17e3.35 (m, 2H, CH2), 3.75 (s, 3H, CH3),
4. Conclusion
d
In this study, a series of novel 3-(2-(2-fluorobenzyloxy)naph-
thalen-6-yl)-2-aminopropanoic acid derivatives with various acyl
groups on the N-terminus have been prepared and identified as
reversible and competitive PTP1B inhibitors with IC50 in the micro-
molar range. Meanwhile, 12h showed the best PTP1B inhibitory
134.4, 133.8, 131.7, 130.1, 129.9, 129.6, 129.2, 128.9, 128.5, 128.0,
127.7, 127.4, 127.0, 119.4, 119.2, 114.3, 114.1, 113.9, 107.6, 107.4, 69.5,
55.5, 54.7, 36.8. MS m/z 456 (M þ 1).
5.1.2. (ꢀ)-Tert-butyl 1-(methoxycarbonyl)-2-(2-hydroxynaphth-
alen-6-yl)ethylcarbamate (5)
potency (IC50 ¼ 1.25 ꢀ 0.24
mM) and the best selectivity (3-fold)
betweenPTP1B and TCPTPwhichmadeitbecomethe leadcompound
for further modification. These results provide a starting point for
further optimization of nonphosphonate-based pTyr mimetics as
PTP1B and PTPs inhibitors. Furthermore, the novel chemical entities
reported in this study could provide a possible opportunity for
developing novel PTP1B inhibitors with promising cell permeability,
bioavailability and improved pharmacological properties.
To a solution of 3 (2.31 g, 10 mmol) in 50 mL of methanol was
added thionyl chloride (0.8 mL, 11 mmol) in a dropwise manner
at ꢂ10 ꢁC. After the addition the solution was allowed warm to
room temperature. The reaction mixture was heated at reflux 3 h
and then concentrated via rotary evaporator to afford the crude
ester. Recrystallization from MeOH:CH2Cl2 (1:5 v/v) afforded 4
(2.27 g, yield 81%) as yellow needles.
Amine hydrochloride 4 (2.82 g,10 mmol) in 50 mL of acetonitrile
at 25 ꢁC was treated with triethylamine (1.52 g,15 mmol) and (BOC)2
(1.5 mL, 10 mmol), and the resulting mixture was stirred for 3 h at
25 ꢁC. The solvent was evaporated under reduced pressure and the
residue was dissolved in dichloromethane, washed with 1 mol/L
sodium bisulfate, saturated sodium bicarbonate, water and brine,
dried over anhydrous MgSO4, and the solvent was removed under
reduced pressure. The resulting residue was purified by silica gel
column chromatography (dichloromethane/methanol, 50:1 v/v) to
afford 5 (3.11 g, yield 90%) as a white solid. m.p.148e149 ꢁC 1H NMR
5. Experimental procedures
5.1. Chemistry
Melting points were determined in open capillary tubes and are
uncorrected. Reaction courses were monitored by TLC on silica gel-
precoated F254 Merck plates. Developed plates were examined
with UV lamps (254 nm). IR spectra were recorded (in KBr) on
a FTIR1730. 1H NMR spectra were measured on a Bruker AV-300
spectrometer using TMS as the internal standard. Mass spectra
were measured on an HP1100LC (Agilent Technologies, USA).
Elemental analyses for C, H and N were within ꢀ0.4% of the
(CDCl3, 300 MHz, ppm): d 1.45 (s, 9H, CH3), 3.11e3.28 (m, 2H, CH2),
3.72 (s, 3H, CH3), 4.65e4.78(m,1H, CH), 7.05e7.62 (m, 6H, AreH). MS
m/z: 345 (M þ 1).

3636
L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
5.1.3. (ꢀ)-N-tert-butoxycarbonyl-3-(2-hydroxynaphthalen-6-yl)
alanine (6)
5.1.8. General procedure for synthesis of 11aer
A solution of appropriate acid (1.0 mmol), DCC (1.1 mmol) and
amine 9 (1.0 mmol) in dichloromethane (50 mL) with catalytic
amount of 4-dimethylaminopyridine (DMAP) were stirred
mechanically at room temperature until acylation reaction was
complete. The N,Nedicyclohexylurea was filtered off and the
filtrate was washed with 5% acetic acid (3 ꢃ 10 mL) and Na2CO3
aqueous solution (3 ꢃ 10 mL) successively. Then the combined
organics were washed with 10 mL water and 10 mL brine succes-
sively, dried (anhydrous MgSO4). The solvent was removed under
reduced pressure to give the crude esters 11aer.
To a solution of 5 (0.35 g, 1.0 mmol) in MeOH (10 mL) at 0 ꢁC,
1 mol/L NaOH (2 mL) was added and stirred for 2 h. The reaction
mixture was filtered and the filtrate was neutralized slowly with
1 mol/L HCl. The resulting white precipitate was filtered, thor-
oughly washed with water, and dried to give crude acid 6. The
crude product was crystallized from hot ethanol as colorless crys-
tals (0.24 g, 74%): m.p. 169e171 ꢁC 1H NMR (CDCl3, 300 MHz, ppm):
d
1.45 (s, 9H, CH3), 3.10e3.26 (m, 2H, CH2), 4.68e4.73 (m, 1H, CH),
6.97e7.59 (m, 6H, AreH). MS m/z: 332 (M þ 1).
5.1.4. (ꢀ)-Tert-butyl 1-(methoxycarbonyl)-2-(2-(2-fluorobenzyl-
oxy)naphthalen-6-yl)ethylcarbamate (7)
5.1.9. General procedure for synthesis of 12aer
A solution of 11aer (1.0 mmol) in THF/MeOH/1.0 M LiOH (3:1:1,
15 mL) was stirred under N2 for 2 h. The solution was evaporated in
vacuo and the residue was dissolved in H2O (10 mL) and slowly
neutralized to pH 5 using cold 1 mol/L HC1. The mixture was then
extracted with EtOAc (15 mL). This extract was washed with brine
(25 mL), dried over anhydrous MgSO4, and the solvent was
removed under reduced pressure. The resulting residue was puri-
fied by silica gel column chromatography (dichloromethane/
methanol, 20:1 v/v). The yield, melting point and spectral data of
each compound are given below.
A solution of 5 (0.35 g, 1.0 mmol) in acetone (15 mL) was treated
with 1-(chloromethyl)-2-fluorobenzene (0.17 g, 1.2 mmol) and
K2CO3 (0.17 g, 1.2 mmol) at 70 ꢁC for 4 h. The reaction mixture was
filtered and the filtrate was concentrated to afford the crude
product. The resulting residue was purified by silica gel column
chromatography (dichloromethane/methanol, 100:1 v/v) to afford
7 (0.42 g, yield 93%) as a white solid. m.p. 156e158 ꢁC 1H NMR
(CDCl3, 300 MHz, ppm): d 1.40 (s, 9H, CH3), 3.18e3.23 (m, 2H, CH2),
3.71 (s, 3H, CH3), 4.62e4.65 (m, 1H, CH), 5.33 (s, 2H, CH2), 7.06e8.07
(m, 10H, AreH). MS m/z: 454 (M þ 1).
5.1.9.1. (ꢀ)-2-(2-(4-Chlorophenyl)acetamido)-3-(2-(2-fluorobenzyl-
oxy)naphthalen-6-yl)propanoic acid (12a). Yield 47%; m.p.
214e216 ꢁC. IR (KBr) cmꢂ1: 3465 (NH), 1688(C]O), 1673 (C]O). 1H
5.1.5. (ꢀ)-N-tert-butoxycarbonyl-3-(2-(2-fluorobenzyloxy)
naphthalen-6-yl)alanine (8)
To a solution of 7 (0.45 g, 1.0 mmol) in MeOH (10 mL) at 0 ꢁC,
1 mol/L NaOH (2 mL) was added and stirred for 2 h. To the reaction
mixture, EtOAc (30 mL) was added and acidified with 1 mol/L HCl.
Extracted with EtOAc (3 ꢃ 10 mL), combined extracts were washed
with water and brine and dried (anhydrous MgSO4). The crude
product after concentration was purified by silica gel column
chromatography (dichloromethane/methanol, 25:1 v/v) to afford 8
(0.37 g, 82%) as a white solid. m.p. 186e188 ꢁC 1H NMR (DMSOed6,
NMR (DMSOed6, 300 MHz, ppm): d 3.10e3.16 (m, 1H, CH2),
3.28e3.33 (m, 1H, CH2), 3.47e3.49 (d, 2H, J ¼ 6.3 Hz, CH2),
4.79e4.83 (m, 1H, CH), 5.28 (s, 2H, CH2), 7.14e7.71 (m, 14H, AreH).
MS m/z: 492 (M þ 1). Anal. Calcd for C28H23ClFNO4: C, 68.36; H,
4.71; N, 2.85. Found: C, 68.24; H, 4.65; N, 2.94.
5.1.9.2. (ꢀ)-2-(2-(4-Chlorophenoxy)acetamido)-3-(2-(2-fluoroben-
zyloxy)naphthalen-6-yl)propanoic acid (12b). Yield 56%; m.p.
183e185 ꢁC. IR (KBr) cmꢂ1: 3438 (NH), 1685 (C]O), 1668 (C]O).
300 MHz, ppm):
d 1.45 (s, 9H, CH3), 3.10e3.26 (m, 2H, CH2),
4.70e4.72 (m, 1H, CH), 5.30 (s, 2H, CH2), 6.99e7.70 (m, 10H, AreH).
MS m/z: 440 (M þ 1).
1H NMR (DMSOed6, 300 MHz, ppm):
d 3.22e3.29 (m, 1H, CH2),
3.37e3.43 (m, 1H, CH2), 4.46e4.48 (d, 2H, J ¼ 6.0 Hz, CH2),
4.88e4.92 (m, 1H, CH), 5.30 (s, 2H, CH2), 6.85e7.76 (m, 15H,
AreH). MS m/z: 508 (M þ 1). Anal. Calcd for C28H23ClFNO5: C,
66.21; H, 4.56; N, 2.76. Found: C, 66.29; H, 4.48; N, 2.84.
5.1.6. (ꢀ)-Methyl 3-(2-(2-fluorobenzyloxy)naphthalen-6-yl)-2-
aminopropanoate (9)
To a stirred solution of 0.45 g (1.0 mmol) of Boc-protected 7 in
15 mL of dichloromethane at room temperature was added 10 mL
(10% volume) of trifluoroacetic acid. After stirring for 5 h, the
reaction was quenched with 0.1 mol/L NaOH, and the layers were
separated. The organics were washed with water, the layers sepa-
rated, and the organics dried (anhydrous MgSO4), and the solvent
was removed in vacuo to give 9 as the trifluoroacetate salt: 1H NMR
(CDCl3, 300 MHz, ppm): d 3.30e3.32 (m, 2H, CH2), 3.59 (s, 3H, CH3),
4.20e4.24 (m, 1H, CH), 5.13 (s, 2H, CH2), 6.98e7.68 (m, 10H, AreH).
MS m/z: 354 (M þ 1).
5.1.9.3. (ꢀ)-3-(2-(2-Fluorobenzyloxy)naphthalen-6-yl)-2-(3-
phenylpropanamido)propanoic acid (12c). Yield 47%; m.p.
177e179 ꢁC. IR (KBr) cmꢂ1: 3465 (NH), 1693 (C]O), 1678 (C]O). 1H
NMR (DMSOed6, 300 MHz, ppm):
d
2.47e2.52 (t, 2H, J ¼ 15 Hz, CH2),
2.87e2.82 (t, 2H, J ¼ 15 Hz, CH2), 3.10e3.18 (m, 1H, CH2), 3.26e3.33
(m, 1H, CH2), 4.83e4.85 (m, 1H, CH), 5.30 (s, 2H, CH2), 7.16e7.77 (m,
15H, AreH). MS m/z: 472 (M þ 1). Anal. Calcd for C29H26FNO4: C,
73.87; H, 5.56; N, 2.97. Found: C, 73.76; H, 5.64; N, 2.83.
5.1.9.4. (ꢀ)-3-(2-(2-Fluorobenzyloxy)naphthalen-6-yl)-2-((E)-cinna-
mamido)propanoic acid (12d). Yield 72%; m.p. 158e161 ꢁC. IR (KBr)
cmꢂ1: 3469 (NH), 1698 (C]O), 1687 (C]O). 1H NMR (DMSOed6,
5.1.7. (ꢀ)-3-(2-(2-Fluorobenzyloxy)naphthalen-6-yl)-2-
aminopropanoic acid (10)
To a solution of 9 (0.35 g, 1.0 mmol) in MeOH (10 mL) at 0 ꢁC,
1 mol/L NaOH (2 mL) was added and stirred for 2 h. To the reaction
mixture, EtOAc (30 mL) was added and acidified with 1 mol/L HCl.
Extracted with EtOAc (3 ꢃ 10 mL), combined extracts were washed
with water and brine and dried (anhydrous MgSO4). The crude
product after concentration was purified by silica gel column
chromatography (dichloromethane/methanol, 25:1 v/v) to afford
10 (0.22 g, 64%) as a white solid. m.p. 177e179 ꢁC 1H NMR
300 MHz, ppm):
4.96e4.99 (m, 1H, CH), 5.36 (s, 2H, CH2), 6.77e6.82 (d, 1H,
J ¼ 15.2 Hz, CH]CH, eH), 7.22e7.27 (d, 1H, J ¼ 15.2 Hz, CH]CH,
d 3.28e3.37 (m, 1H, CH2), 3.59e3.62 (m, 1H, CH2),
a
b
eH), 6.88e7.87 (m, 15H, AreH). MS m/z: 470 (M þ 1). Anal. Calcd
for C29H24FNO4: C, 74.19; H, 5.15; N, 2.98. Found: C, 74.30; H, 5.08;
N, 2.89.
5.1.9.5. (ꢀ)-2-((E)-3-(2-fluorophenyl)acrylamido)-3-(2-(2-fluoro-
benzyloxy)naphthalen-6-yl)propanoic acid (12e). Yield 61%; m.p.
187e189 ꢁC. IR (KBr) cmꢂ1: 3460 (NH), 1702 (C]O), 1687 (C]O). 1H
(DMSOed6, 300 MHz, ppm):
d 3.04e3.24 (m, 2H, CH2), 3.90e3.92
(m, 1H, CH), 5.20 (s, 2H, CH2), 6.99e7.69 (m, 10H, AreH). MS m/z:
340 (M þ 1).
NMR (DMSOed6, 300 MHz, ppm):
d 3.02e3.09 (m, 1H, CH2),

L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
3637
3.24e3.29 (m, 1H, CH2), 4.62e4.65 (m, 1H, CH), 5.22 (s, 2H, CH2),
6.76e6.81 (d, 1H, J ¼ 15.6 Hz, CH]CH, eH), 7.41e7.46 (d, 1H,
eH), 7.17e7.77 (m, 14H, AreH). MS m/z: 488
5.1.9.12. (ꢀ)-2-((E)-3-(4-bromophenyl)acrylamido)-3-(2-(2-fluoro-
benzyloxy)naphthalen-6-yl)propanoic acid (12l). Yield 65%; m.p.
201e203 ꢁC. IR (KBr) cmꢂ1: 3451 (NH), 1701 (C]O), 1687 (C]O).
a
J ¼ 15.6 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23F2NO4: C, 71.45; H, 4.76; N, 2.87.
1H NMR (DMSOed6, 300 MHz, ppm):
d
3.23e3.60 (m, 1H, CH2),
3.06e3.12 (m, 1H, CH2), 4.59e4.63 (m, 1H, CH), 5.22 (s, 2H, CH2),
6.68e6.73 (d, 1H, J ¼ 15.6 Hz, CH]CH, eH), 7.31e7.36 (d, 1H,
eH), 7.17e7.77 (m, 14H, AreH). MS m/z 549
Found: C, 71.34; H, 4.84; N, 2.96.
a
5.1.9.6. (ꢀ)-2-((E)-3-(3-fluorophenyl)acrylamido)-3-(2-(2-fluorobe-
nzyloxy)naphthalen-6-yl)propanoic acid (12f). Yield 70%; m.p.
186e188 ꢁC. IR (KBr) cmꢂ1: 3464 (NH), 1696 (C]O), 1681 (C]O).
J ¼ 15.6 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23BrFNO4: C, 63.51; H, 4.23; N, 2.55.
Found: C, 63.68; H, 4.33; N, 2.42.
1H NMR (DMSOed6, 300 MHz, ppm):
d
3.03e3.10 (m, 1H, CH2),
3.24e3.30 (m, 1H, CH2), 4.61e4.65 (m, 1H, CH), 5.23 (s, 2H, CH2),
6.71e6.76 (d, 1H, J ¼ 15.6 Hz, CH]CH, eH), 7.37e7.42 (d, 1H,
eH), 7.08e7.77 (m, 14H, AreH). MS m/z 488
5.1.9.13. (ꢀ)-2-((E)-3-(2,4-dichlorophenyl)acrylamido)-3-(2-(2-
fluorobenzyloxy)naphthalen-6-yl)propanoic acid (12m). Yield
73%; m.p. 181e182 ꢁC. IR (KBr) cmꢂ1: 3462 (NH), 1696 (C]O),
a
J ¼ 15.6 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23F2NO4: C, 71.45; H, 4.76; N, 2.87.
1681 (C]O). 1H NMR (DMSOed6, 300 MHz, ppm):
d
3.22e3.28
(m, 1H, CH2), 3.37e3.43 (m, 1H, CH2), 4.93e4.97 (m, 1H, CH),
5.36 (s, 2H, CH2), 6.82e6.87 (d, 1H, J ¼ 15.2 Hz, CH]CH, eH),
eH), 7.18e7.87 (m, 13H,
Found: C, 71.32; H, 4.85; N, 2.93.
a
5.1.9.7. (ꢀ)-2-((E)-3-(4-fluorophenyl)acrylamido)-3-(2-(2-fluorob-
enzyloxy)naphthalen-6-yl)propanoic acid (12g). Yield 72%; m.p.
171e174 ꢁC. IR (KBr) cmꢂ1:3468 (NH), 1697 (C]O), 1685 (C]O).
7.27e7.32 (d, 1H, J ¼ 15.2 Hz, CH]CH,
b
AreH). MS m/z: 539 (M þ 1). Anal. Calcd for C29H22Cl2FNO4: C,
64.69; H, 4.12; N, 2.60. Found: C, 64.55; H, 4.24; N, 2.46.
1H NMR (DMSOed6, 300 MHz, ppm):
d
3.02e3.07 (m, 1H, CH2),
3.22e3.27 (m, 1H, CH2), 4.60e4.64 (m, 1H, CH), 5.26 (s, 2H, CH2),
6.74e6.79 (d, 1H, J ¼ 15.6 Hz, CH]CH, eH), 7.39e7.44 (d, 1H,
eH), 7.16e7.73 (m, 14H, AreH). MS m/z 488
5.1.9.14. (ꢀ)-2-((E)-3-(3,4-dichlorophenyl)acrylamido)-3-(2-(2-
fluorobenzyloxy)naphthalen-6-yl)propanoic acid (12n). Yield
66%; m.p. 181e183 ꢁC. IR (KBr) cmꢂ1: 3448 (NH), 1690 (C]O), 1682
a
J ¼ 15.6 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23F2NO4: C, 71.45; H, 4.76; N, 2.87.
(C]O). 1H NMR (DMSOed6, 300 MHz, ppm):
d
3.06e3.12 (m, 1H,
CH2), 3.23e3.30 (m, 1H, CH2), 4.62e4.66 (m, 1H, CH), 5.22 (s, 2H,
CH2), 6.66e6.71 (d, 1H, J ¼ 15.3 Hz, CH]CH, eH), 7.23e7.28 (d, 1H,
eH), 7.16e7.77 (m, 13H, AreH). MS m/z 539
Found: C, 71.29; H, 4.89; N, 2.79.
a
5.1.9.8. (ꢀ)-2-((E)-3-(2-chlorophenyl)acrylamido)-3-(2-(2-fluorob-
enzyloxy)naphthalen-6-yl)propanoic acid (12h). Yield 72%; m.p.
223e225 ꢁC. IR (KBr) cmꢂ1: 3445 (NH), 1702 (C]O), 1688 (C]O).
J ¼ 15.3 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H22Cl2FNO4: C, 64.69; H, 4.12; N, 2.60.
Found: C, 64.58; H, 4.21; N, 2.72.
1H NMR (DMSOed6, 300 MHz, ppm):
d
3.03e3.10 (m, 1H, CH2),
3.22e3.27 (m, 1H, CH2), 4.62e4.64 (m, 1H, CH), 5.25 (s, 2H, CH2),
6.77e6.82 (d, 1H, J ¼ 15.3 Hz, CH]CH, eH), 7.36e7.41 (d, 1H,
eH), 7.14e7.77 (m, 14H, AreH). MS m/z 505
5.1.9.15. (ꢀ)-2-((E)-3-(3-methoxyphenyl)acrylamido)-3-(2-(2-
fluorobenzyloxy)naphthalen-6-yl)propanoic acid (12o). Yield
59%; m.p. 219e220 ꢁC. IR (KBr) cmꢂ1: 3458 (NH), 1692 (C]O), 1675
a
J ¼ 15.3 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23ClFNO4: C, 69.12; H, 4.60; N, 2.78.
(C]O). 1H NMR (DMSOed6, 300 MHz, ppm):
d
3.10e3.16 (m, 1H,
CH2), 3.33e3.39 (m, 1H, CH2), 3.75 (s, 3H, OCH3), 4.75e4.79 (m, 1H,
CH), 5.27 (s, 2H, CH2), 6.61e6.66 (d, 1H, J ¼ 15.6 Hz, CH]CH, eH),
eH), 7.01e7.70 (m, 14H,
Found: C, 69.31; H, 4.48; N, 2.64.
a
5.1.9.9. (ꢀ)-2-((E)-3-(3-chlorophenyl)acrylamido)-3-(2-(2-fluorob-
enzyloxy)naphthal -en-6-yl)propanoic acid (12i). Yield 72%; m.p.
199e202 ꢁC. IR (KBr) cmꢂ1: 3460 (NH), 1693 (C]O), 1680 (C]O).
7.34e7.40 (d, 1H, J ¼ 15.6 Hz, CH]CH,
b
AreH). MS m/z 501 (M þ 1). Anal. Calcd for C30H26FNO5: C, 72.13; H,
5.25; N, 2.80. Found: C, 72.03; H, 5.32; N, 2.74.
1H NMR (DMSOed6, 300 MHz, ppm):
d
3.02e3.10 (m, 1H, CH2),
3.22e3.28 (m, 1H, CH2), 4.62e4.64 (m, 1H, CH), 5.22 (s, 2H, CH2),
6.74e6.79 (d, 1H, J ¼ 15.6 Hz, CH]CH, eH), 7.42e7.47 (d, 1H,
eH), 7.16e7.76 (m, 14H, AreH). MS m/z: 505
5.1.9.16. (ꢀ)-2-((E)-3-(4-methoxyphenyl)acrylamido)-3-(2-(2-
fluorobenzyloxy)naphthalen-6-yl)propanoic acid (12p). Yield
67%; m.p. 191e193 ꢁC. IR (KBr) cmꢂ1: 3453 (NH), 1696 (C]O), 1681
a
J ¼ 15.6 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23ClFNO4: C, 69.12; H, 4.60; N, 2.78.
(C]O). 1H NMR (DMSOed6, 300 MHz, ppm):
d
3.08e3.15 (m, 1H,
CH2), 3.22e3.28 (m, 1H, CH2), 3.76 (s, 3H, OCH3), 4.64e4.68 (m, 1H,
CH), 5.22 (s, 2H, CH2), 6.76e6.81 (d, 1H, J ¼ 15.3 Hz, CH]CH, eH),
eH), 7.11e7.87 (m, 14H,
Found: C, 69.27; H, 4.45; N, 2.61.
a
5.1.9.10. (ꢀ)-2-((E)-3-(4-chlorophenyl)acrylamido)-3-(2-(2-fluorob-
enzyloxy)naphthalen-6-yl)propanoic acid (12j). Yield 69%; m.p.
189e191 ꢁC. IR (KBr) cmꢂ1: 3451 (NH), 1705 (C]O), 1687 (C]O). 1H
7.21e7.26 (d, 1H, J ¼ 15.3 Hz, CH]CH,
b
AreH). MS m/z 501 (M þ 1). Anal. Calcd for C30H26FNO5: C, 72.13; H,
5.25; N, 2.80. Found: C, 72.21; H, 5.34; N, 2.89.
NMR (DMSOed6, 300 MHz, ppm):
3.26e3.32 (m, 1H, CH2), 4.70e4.74 (m, 1H, CH), 5.29 (s, 2H, CH2),
6.78e6.83 (d, 1H, J ¼ 15.3 Hz, CH]CH, eH), 7.47e7.52 (d, 1H,
eH), 7.20e7.78 (m, 14H, AreH). MS m/z 577
d 3.08e3.14 (m, 1H, CH2),
5.1.9.17. (ꢀ)-2-((E)-3-(3,4-dimethoxyphenyl)acrylamido)-3-(2-(2-
fluorobenzyloxy)naphthalen-6-yl)propanoic acid (12q). Yield 54%;
m.p.175e177 ꢁC. IR (KBr) cmꢂ1:3456 (NH),1691 (C]O),1686 (C]O).
a
J ¼ 15.3 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23ClFNO4: C, 69.12; H, 4.60; N, 2.78.
1H NMR (DMSOed6, 300 MHz, ppm):
d 3.00e3.05 (m, 1H, CH2),
Found: C, 69.30; H, 4.71; N, 2.63.
3.23e3.29 (m, 1H, CH2), 3.98 (s, 3H, OCH3), 4.00 (s, 3H, OCH3),
4.74e4.78 (m,1H, CH), 5.30 (s, 2H, CH2), 6.63e6.68 (d,1H, J ¼ 15.4 Hz,
5.1.9.11. (ꢀ)-2-((E)-3-(2-bromophenyl)acrylamido)-3-(2-(2-fluoro-
benzyloxy)naphthalen-6-yl)propanoic acid (12k). Yield 63%; m.p.
194e196 ꢁC. IR (KBr) cmꢂ1: 3462 (NH), 1695 (C]O), 1681 (C]O).
CH]CH,
a
eH), 7.29e7.34(d,1H,J ¼ 15.4 Hz,CH]CH,
beH), 7.17e7.71
(m, 13H, AreH). MS m/z 531 (M þ 1). Anal. Calcd for C31H28FNO6: C,
70.31; H, 5.33; N, 2.64. Found: C, 70.42; H, 5.39; N, 2.71.
1H NMR (DMSOed6, 300 MHz, ppm):
d
3.08e3.14 (m, 1H, CH2),
3.34e3.40 (m, 1H, CH2), 4.65e4.69 (m, 1H, CH), 5.23 (s, 2H, CH2),
6.69e6.74 (d, 1H, J ¼ 15.4 Hz, CH]CH, eH), 7.30e7.35 (d, 1H,
eH), 7.17e7.78 (m, 14H, AreH). MS m/z 549
5.1.9.18. (ꢀ)-2-((E)-3-p-tolylacrylamido)-3-(2-(2-fluorobenzyloxy)
naphthalen-6-yl)propanoic acid (12r). Yield 58%; m.p. 168e170 ꢁC.
IR (KBr) cmꢂ1: 3452 (NH), 1695 (C]O), 1686 (C]O). 1H NMR
a
J ¼ 15.4 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C29H23BrFNO4: C, 63.51; H, 4.23; N, 2.55.
(DMSOed6, 300 MHz, ppm):
d 2.22 (s, 3H, CH3), 3.23e3.29 (m, 1H,
Found: C, 63.70; H, 4.31; N, 2.47.
CH2), 3.36e3.41 (m, 1H, CH2), 4.58e4.62 (m, 1H, CH), 5.22 (s, 2H,

3638
L.-P. Sun et al. / European Journal of Medicinal Chemistry 46 (2011) 3630e3638
[14] B.A. Zinker, C.M. Rondinone, J.M. Trevillyan, R.J. Gum, J.E. Clampit, J.F. Waring,
N. Xie, D. Wilcox, P. Jacobson, L. Frost, P.E. Kroeger, R.M. Reilly, S. Koterski,
T.J. Opgenorth, R.G. Ulrich, S. Crosby, M. Butler, S.F. Murray, R.A. McKay,
S. Bhanot, B.P. Monica, M.R. Jirousek, PNAS U.S.A. 99 (2002) 11357e11362.
[15] C.M. Rondinone, J.M. Trevillyan, J.E. Clampit, R.J. Gum, C. Berg, P. Kroeger,
L. Frost, B.A. Zinker, R. Reilly, R. Ulrich, M. Butler, B.P. Monia, M.R. Jirousek,
J.F. Waring, Diabetes 51 (2002) 2405e2411.
CH2), 6.62e6.67 (d, 1H, J ¼ 15.3 Hz, CH]CH,
aeH), 7.16e7.21 (d, 1H,
eH), 7.00e7.75 (m, 15H, AreH). MS m/z 484
J ¼ 15.3 Hz, CH]CH,
b
(M þ 1). Anal. Calcd for C30H26FNO4: C, 74.52; H, 5.42; N, 2.90.
Found: C, 74.41; H, 5.49; N, 2.79.
5.2. Biological assay
[16] R.J. Gum, L.L. Gaede, S. Koterski, M. Heindel, J.E. Clampit, B.A. Zinker,
J.M. Trevillyan, R. Ulrich, M.R. Jirousek, C.M. Rondinone, Diabetes 52 (2003)
21e28.
[17] C. Ramachandran, B.P. Kennedy, Curr. Top. Med. Chem. 3 (2003) 749e757.
[18] T.R. Burke Jr., K. Lee, Acc. Chem. Res. 36 (2003) 426e433.
[19] A.P. Combs, J. Med. Chem. 53 (2010) 2333e2344.
5.2.1. PTP1B and related PTPs biological assay
The enzymatic assays of PTP1B and related PTPs were referred in
Ref. [30].
[20] M.J. Hartshorn, C.W. Murray, A. Cleasby, M. Frederickson, I.J. Tickle, H. Jhoti,
J. Med. Chem. 48 (2005) 403e413.
5.2.2. Characterization of the inhibitors’ enzyme kinetics
The enzyme kinetics assays of compound 12h were referred in
Ref. [32].
[21] D.P. Wilson, Z.K. Wan, W.X. Xu, S.J. Kirincich, B.C. Follows, D. Joseph-McCarthy,
K. Foreman, A. Moretto, J. Wu, M. Zhu, E. Binnun, Y.L. Zhang, M. Tam, D.V. Erbe,
J. Tobin, X. Xu, L. Leung, A. Shilling, S.Y. Tam, T.S. Mansour, J. Lee, J. Med. Chem.
50 (2007) 4681e4698.
[22] M. Hussain, V. Ahmed, B. Hill, Z. Ahmed, S.D. Taylor, Bioorg. Med. Chem. 16
(2008) 6764e6777.
Acknowledgments
[23] M. Sarmiento, Y.A. Puius, S.W. Vetter, Y.F. Keng, L. Wu, Y. Zhao, D.S. Lawrence,
S.C. Almo, Z.Y. Zhang, Biochemistry 39 (2000) 8171e8179.
[24] T.N. Doman, S.L. McGovern, B.J. Witherbee, T.P. Kasten, R. Kurumbail,
W.C. Stallings, D.T. Connolly, B.K. Shoichet, J. Med. Chem. 45 (2002) 2213e2221.
[25] A.P. Combs, E.W. Yue, M. Bowe, P.J. Ala, B. Wayland, B. Douty, A. Takvorian,
P. Polam, Z. Wasserm, W.Y. Zhu, M.L. Crawley, J. Pruitt, R. Sparks, B. Glass,
D. Modi, E. McLaughlin, L. Bostrom, M. Li, L. Galya, K. Blom, M. Hillman,
L. Gonneville, B.G. Reid, M. Wei, M. Becker-Pasha, R. Klabe, R. Huber, Y.L. Li,
G. Hollis, T.C. Burn, R. Wynn, P. Liu, B. Metcalf, J. Med. Chem. 48 (2005)
6544e6548.
[26] A.F. Moretto, S.J. Kirincich, W.X. Xu, M.J. Smith, Z.-K. Wan, D.P. Wilson,
B.C. Follows, E. Binnun, D. Joseph-McCarthy, K. Foreman, D.V. Erbe, Y.L. Zhang,
S.K. Tam, S.Y. Tam, J. Lee, Bioorg. Med. Chem. 14 (2006) 2162e2177.
[27] V.S. Murthy, V.M. Kulkarni, Bioorg. Med. Chem. 10 (2002) 897e906.
[28] H. Zhao, G. Liu, Z. Xin, M.D. Serby, Z. Pei, B.G. Szczepankiewicz, P.J. Hajduk,
C. Abad-Zapatero, C.W. Hutchins, T.H. Lubben, S.J. Ballaron, D.L. Haasch,
W. Kaszubska, C.M. Rondinone, J.M. Trevillyan, M.R. Jirousek, Bioorg. Med.
Chem. Lett. 14 (2004) 5543e5546.
This work was supported by the National Natural Science
Foundation of China (20962021), National Science & Technology
Major Project of China “Key New Drug Creation and Manufacturing
Program” (2009ZX09302-001), the National Science & Technology
Major Project (Nos. 2007CB914201), the Natural Science Founda-
tion of China (Nos. 81021062, 30801405), Shanghai Commission of
Science and Technology (Grant 09DZ2291200).
References
[1] B.G. Neel, N.K. Tonks, Curr. Opin. Cell Biol. 9 (1997) 193e204.
[2] T. Hunter, Cell 100 (2000) 113e127.
[3] N.K. Tonks, B.G. Neel, Curr. Opin. Cell Biol. 13 (2001) 182e195.
[4] A. Alonso, J. Sasin, N. Bottini, I. Friedberg, A. Osterman, A. Godzik, T. Hunter,
J. Dixon, T. Mustelin, Cell 117 (2004) 699e711.
[29] M. Sarmiento, L. Wu, Y. Keng, L. Song, Z. Luo, Z. Huang, G. Wu, A.K. Yuan,
Z. Zhang, J. Med. Chem. 43 (2000) 146e155.
[30] M.A. Vela, F.R. Fronczek, G.W. Horn, M.L. McLaughlin, J. Org. Chem. 55 (1990)
2913e2918.
[31] W. Zhang, D. Hong, Y.Y. Zhou, Y.N. Zhang, Q. Shen, J.Y. Li, L.H. Hu, J. Li, Biochim.
Biophys. Acta 1760 (2006) 1505e1512.
[32] G. Liu, Z. Xin, Z. Pei, P.J. Hajduk, C. Abad-Zapatero, C.W. Hutchins, H. Zhao,
T.H. Lubben, S.J. Ballaron, D.L. Haasch, W. Kaszubska, C.M. Rondinone,
J.M. Trevillyan, M.R. Jirousek, J. Med. Chem. 46 (2003) 4232e4235.
[33] A.P. Ducruet, A. Vogt, P. Wipf, J.S. Lazo, Annu. Rev. Pharmacol. Toxicol. 45
(2005) 725e750.
[34] Y.N. Zhang, W. Zhang, D. Hong, L. Shi, Q. Shen, J.Y. Li, J. Li, L.H. Hu, Bioorg. Med.
Chem. 16 (2008) 8697e8705.
[35] L. Shi, H.P. Yu, Y.Y. Zhou, J.Q. Du, Q. Shen, J.Y. Li, J. Li, Acta Pharmacol. Sin 29
(2008) 278e284.
[36] S.L. McGovern, B.T. Helfand, B. Feng, B.K. Shoichet, J. Med. Chem. 46 (2003)
4265e4272.
[5] K.R. Schiller, L.J. Mauro, J. Cell Biochem. 96 (2005) 262e277.
[6] P. Blume-Jensen, T. Hunter, Nature 411 (2001) 355e365.
[7] W.S. Cook, R.H. Unger, Dev. Cell 2 (2002) 385e387.
[8] J. Montalibet, B.P. Kennedy, Drug Discov. Today Therap. Strateg. 2 (2005)
129e135.
[9] J.C.H. Byon, A.B. Kusari, J. Kusari, Mol. Cell Biochem. 182 (1998) 101e108.
[10] S. Walchi, M.L. Curchod, R.P. Gobert, S. Arkinstall, R. Hooft van Huijsduijnen,
J. Biol. Chem. 275 (2000) 9792e9796.
[11] A. Cheng, N. Dubé, F. Gu, M.L. Tremblay, Eur. J. Biochem. 269 (2002) 1050e1059.
[12] M. Elchebly, P. Payette, E. Michaliszyn, W. Cromlish, S. Collins, A.L. Loy,
D. Normandin, A. Cheng, J. Himms-Hagen, C.C. Chan, C. Ramachandran,
M.J. Gresser, M.L. Tremblay, B.P. Kennedy, Science 283 (1999) 1544e1548.
[13] L.D. Klaman, O. Boss, O.D. Peroni, J.K. Kim, J.L. Martino, J.M. Zabolotny,
N. Moghal, M. Lubkin, Y.B. Kim, A.H. Sharpe, A. Stricker-Krongrad,
G.I. Shulman, B.G. Neel, B.B. Kahn, Mol. Cell Biol. 20 (2000) 5479e5489.