Bromophenols as inhibitors of protein tyrosine phosphatase 1B with antidiabetic properties

Article abstract of DOI:10.1016/j.bmcl.2012.02.074

A series of bromophenol derivatives were synthesized and evaluated as protein tyrosine phosphatase 1B (PTP1B) inhibitors in vitro and in vivo based on bromophenol 4e (IC₅₀ = 2.42 μmol/L), which was isolated from red algae Rhodomela confervoides

Full text of DOI:10.1016/j.bmcl.2012.02.074

Bioorganic & Medicinal Chemistry Letters 22 (2012) 2827–2832
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Bromophenols as inhibitors of protein tyrosine phosphatase
1B with antidiabetic properties
Dayong Shi a, , Jing Li a, Bo Jiang a, Shuju Guo a, Hua Su a, Tao Wang b
⇑
a Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
b Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing 210009, 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 bromophenol derivatives were synthesized and evaluated as protein tyrosine phosphatase 1B
Received 29 December 2011
Revised 13 February 2012
Accepted 23 February 2012
Available online 2 March 2012
(PTP1B) inhibitors in vitro and in vivo based on bromophenol 4e (IC50 = 2.42 lmol/L), which was isolated
from red algae Rhodomela confervoides. The results showed that all of the synthesized compounds dis-
played weak to good PTP1B inhibition at tested concentration. Among them, highly brominated com-
pound 4g exhibited promising inhibitory activity against PTP1B with IC50 0.68 lmol/L, which was
approximately fourfold more potent than lead compound 4e. Further, compound 4g demonstrated high
selectivity against other PTPs (TCPTP, LAR, SHP-1 and SHP-2). More importantly, in vivo antidiabetic
activities investigations of compound 4g also demonstrated inspiring results.
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Bromophenol derivatives
Protein tyrosine phosphatase 1B
Diarylmethane
Antidiabetic activities
In recent years, protein tyrosine phosphatase 1B (PTP1B), the
first characterized protein tyrosine phosphatase (PTPases), has at-
tracted intensive research because of its involvement in the insulin
signaling cascade as a major negative regulator.1 Accumulating
evidence indicate that PTP1B could dephosphorylate the insulin
receptor (IR) or insulin receptor substrate (IRS) in skeletal muscle
and liver, which involved in the control of insulin signaling path-
way, and these signaling events result in the homeostatic regula-
tion of the blood glucose level.2–4 In addition, molecular biology
investigations have been already proved that PTP1B knock-out
mice exhibit the phenotypes of increased insulin sensitivity, im-
proved glucose tolerance, and resistance to diet-induced obesity.5,6
Based on above research results, the inhibition of PTP1B has
emerged as a novel therapeutic strategy for the treatments of type
2 diabetes mellitus.
them, bromophenol 4e showed good inhibitory activity against
PTP1B in vitro (IC50 = 2.42
mol/L),14 which makes it an attractive
l
starting point to be developed into more potent small molecular
PTP1B inhibitor. Based on the naturally potent PTP1B inhibitor, a
series of bromophenol derivatives have been synthesized and eval-
uated as a novel class of small molecular PTP1B inhibitors. Their
structures are shown in Figure 1.
In the past decades, there were a number of reports on the de-
sign and development of synthetic PTP1B inhibitors.7,8 At the same
while, more and more studies were focused on PTP1B inhibitors
isolated from plants.9–13 In our screening program to search for
PTP1B inhibitors from marine algae, the ethanol-soluble extract
of Rhodomela confervoides exhibited significant inhibitory activity
against PTP1B in vitro. The results were also confirmed by follow-
ing in vivo anti-hyperglycemic effects on streptozotocin-diabetes
in male Wistar rats fed with high fat diet.14 Then bioassay-guided
separation of ethanol extract using a variety of chromatographic
techniques lead to a series of bromophenol derivatives.15 One of
⇑
Corresponding author. Tel.: +86 0532 8289 8719; fax: +86 0532 8289 8641.
E-mail address: shidayong@qdio.ac.cn (D. Shi).
Figure 1. Structures of synthetic bromophenol derivatives.
0960-894X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2012.02.074

2828
D. Shi et al. / Bioorg. Med. Chem. Lett. 22 (2012) 2827–2832
Scheme 1. Reagents and conditions: (i) PPA, 80 °C, 1 h; (ii) Br2 (1.1 equiv), CH2Cl2, rt; (iii) Br2 (2 equiv), AcOH, rt; (iv) Br2 (1.1 equiv), AlCl3, AcOH, 40 °C; (v) Br2 (3 equiv), AlCl3,
AcOH, 80 °C; (vi) NBS (1 equiv), AcOH, concd H2SO4, 0 °C to rt; (vii) NBS (2 equiv), concd H2SO4, 0 °C to rt.
Scheme 2. Reagents and conditions: (i) Et3SiH, CF3COOH, rt; (ii) Br2 (1 equiv), AlCl3,
AcOH, 70–90 °C; (iii) NBS (2 equiv), concd H2SO4, 0 °C to rt.
Scheme 3. Reagents and conditions: (i) BBr3, dry CH2Cl2, rt, 4 h.

D. Shi et al. / Bioorg. Med. Chem. Lett. 22 (2012) 2827–2832
2829
Table 1
conditions that using 1 equiv of bromine reacted with 1a in CH2Cl2
at 0 °C, mono-brominated compound 1b was obtained in 64% yield,
while in polar solvent acetic acid, di-brominated compound 1c was
yielded in 82% yield.17,18 Inspired by the outcome aforementioned,
further bromination of compound 1c took place smoothly under
the control of quantity of bromine, type of brominating reagent
(Br2 and NBS), solvent polarity (acetic acid and concd H2SO4) and
addition of catalyst (AlCl3) to afforded multi-brominated com-
pounds 1d–g in 40–50% yield.19 As outlined in Scheme 2, reduction
of diarylketone compounds 1a–e were carried out with triethylsi-
lane in trifluoroacetic acid to obtain the corresponding diarylmeth-
ane compounds 3a–e in 73–80% yield.20 Further bromination of
compound 3e took place using process as shown in Scheme 2 to
give compounds 3f and 3g. Finally, demethylation of compounds
1a–g and 3a–g with boron bromide in CH2Cl2 cleanly gave corre-
sponding bromophenols 2a–g and 4a–g in 90–94% yield21,22 and
the synthetic routes are shown in Scheme 3. Analytical data for
the target compounds and intermediates were provided in Ref. 23.
All the derivatives (1a–g, 2a–g, 3a–g and 4a–g) were evaluated
in the enzyme inhibition assay against human recombinant PTP1B
prepared as described.24 As summarized in Table 1, all of the syn-
thetic compounds demonstrated weak to good PTP1B inhibitory
In vitro PTP1B inhibitory activities of synthetic bromophenol derivatives
Compds
Inhibition (%)
20 g/mL
2.72
12.98
33.64
37.55
21.35
69.81
105.06
13.48
11.25
8.74
42.71
20.28
95.07
78.64
38.43
14.42
33.64
52.49
60.44
98.71
96.91
9.27
12.25
20.92
40.45
91.32
92.26
101.05
IC50 (lmol/L)
l
5 lg/mL
1a
1b
1c
1d
1e
1f
1g
2a
2b
2c
2d
2e
2f
2g
3a
3b
3c
3d
3e
3f
3g
4a
4b
4c
4d
4e
4f
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
50.63a
47.83a
ND
3.26b
2.02
ND
ND
ND
ND
ND
ND
ND
ND
ND
72.13a
29.18a
ND
2.45b
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
40.16a
28.95a
49.32a
37.89a
ND
activity at 20 lg/mL. Especially, compounds 1g and 4g exhibited
ND
ND
ND
ND
ND
ND
significant PTP1B inhibition (105.06% and 101.05%, respectively),
which showed stronger inhibitory activity than compound 4e
(91.32%). Compound 3a, the reductive compound of 1a, displayed
38.94a
45.27a
86.72a
2.42
ND
38.42% inhibition that was much higher than 1a (2.72%) at 20 lg/
4g
0.68b
mL. Accordingly, compounds 3d,e demonstrated higher inhibition
than their carbonyl compounds 1d,e. And this trend also partly ap-
plies to compounds 4a–e and 1a–e. In general, the diarylmethane
compounds exhibited more potent PTP1B inhibition than the
diarylmethanones, which indicating that the flexibility of diaryl-
methane scaffold is favorable to PTP1B inhibitory activity. It is also
found that there is no obvious potency difference between com-
pounds with free hydroxyl and their corresponding methylating
ones. Furthermore, it is notable that the multi-brominated
compounds especially the pentabromo- or hexabromo-compounds
(1g, 2f,g, 3f,g and 4e–g) displayed more significant PTP1B inhibi-
tory activity than mono-brominated compounds, indicating that
increasing of the number of bromine substitutions on phenyl ring
promote PTP1B inhibitory activity. In addition to potency improve-
ments, we investigated the selectivity of compound 4g against
other PTPs (TCPTP, LAR, SHP-1 and SHP-2). As shown in Table 2,
compound 4g demonstrated excellent selectivity against TCPTP,
LAR, SHP-1 and SHP-2 (>70-fold).
ND = not determined.
a
Values were tested only if its inhibitory ratio greater than 50% at the dose of
20
lg/mL.
b
Values were tested only if its inhibitory ratio greater than 50% at the dose of
5
lg/mL.
Table 2
Inhibitory activity of compound 4g against various PTPs
Compd
IC50 (lmol/L)
PTP1B
0.68
TCPTP
>50
SHP-1
>50
SHP-2
>50
LAR
>50
4g
The synthetic routes of compounds 1a–g are shown in Scheme
1. Bis-(3,4-dimethoxy-phenyl)-methanone 1a, which was
synthesized by 3,4-dimethoxybenzoic acid 1 on reaction with
1,2-dimethoxybenzene 2 in the presence of polyphosphoric acid
at 80 °C for one hour,16 was regarded as the crucial intermediate
to provide a versatile platform for varying both position and num-
ber of bromine substitution on the phenyl ring. Firstly, treatment
of compound 1a with two equivalents of bromine in apolar solvent
CH2Cl2 to afford the mixture of mono-brominated compound 1b
and di-brominated compound 1c. By modification of the reacting
As an interesting new entity, compound 4g was selected for
further antidiabetic activities evaluation in vivo.25 During 6-week
intervention, body weight and food consumption of db/db mice
in treatment group exhibited a downward trend compared with
the model group, and no obvious toxicity observed. The antihyper-
glycemic activity profile was illustrated in Table 3, compound 4g
was active in vivo at a dose of 25 and 50 mg/kg, decreasing plasma
Table 3
In vivo antihyperglycemic activity profile of compound 4g in db/db mice model
Group
Dose (mg/kg)
Plasma glucose (mmol/L)a
% Decrease in plasma glucose
HbA1c (%)a
Baseline
2 weeks
6 weeks
Control
Model
4g
5.1 0.4
15.5 2.8**
15.6 2.6
15.8 2.4
15.3 2.4
5.2 0.4
16.2 4.0**
18.1 1.6
15.2 2.8
9.7 1.2##
6.7 0.8
2.65 0.40
15.8 1.8**
9.3 1.0##
10.5 2.4##
7.9 1.5##
4.90 0.31**
3.05 0.92##
3.05 0.60##
2.56 0.44##
50
25
50
40.4
33.5
48.4
Rosiglitazone
a
Data are means SD.
P <0.01 when compared to the model group.
P <0.01 when compared to the control group.
##
**

2830
D. Shi et al. / Bioorg. Med. Chem. Lett. 22 (2012) 2827–2832
Table 4
In vivo antidyslipidemic activities of compound 4g
Group
Dose (mg/kg)
Triacylglycerols (mmol/L)a
Total cholesterol (mmol/L)a
Baseline
2 weeks
6 weeks
Baseline
2 weeks
6 weeks
Control
Model
4g
1.16 0.09
1.30 0.25
1.31 0.28
1.29 0.18
1.31 0.38
1.08 0.07
1.24 0.12**
1.28 0.11
1.20 0.13
1.06 0.19#
1.0 5 0.11
1.56 0.17**
1.51 0.23
1.45 0.15
1.29 0.14##
3.6 0.2
6.2 1.7**
6.3 1.8
6.3 1.3
6.1 1.7
3.5 0.2
3.3 0.5
9.2 1.2**
8.4 0.1
9.1 1.0
7.7 1.0#
9.8 0.7**
7.1 1.0##
8.3 0.5##
6.5 0.4##
50
25
50
Rosiglitazone
a
#
Data are means SD.
P <0.05.
P <0.01 when compared to the model group.
P <0.01 when compared to the control group.
##
**
10. Cui, L.; Na, M.; Oh, H.; Bae, E. Y.; Jeong, D. G.; Ryu, S. E.; Kim, S.; Kim, B. Y.; Oh,
W. K.; Ahn, J. S. Bioorg. Med. Chem. Lett. 2006, 16, 1426.
11. Na, M.; Cui, L.; Min, B. S.; Bae, K.; Yoo, J. K.; Kim, B. Y.; Oh, W. K.; Ahn, J. S.
Bioorg. Med. Chem. Lett. 2006, 16, 3273.
12. Na, M.; Hoang, D. M.; Njamen, D.; Mbafor, J. T.; Fomum, Z. T.; Thuong, P. T.;
Ahn, J. S.; Oh, W. K. Bioorg. Med. Chem. Lett. 2007, 17, 3868.
13. Na, M.; Oh, W. K.; Kim, Y. H.; Cai, X. F.; Kim, S.; Kim, B. Y.; Ahn, J. S. Bioorg. Med.
Chem. Lett. 2006, 16, 3061.
14. Shi, D. Y.; Xu, F.; He, J.; Li, J.; Fan, X.; Han, L. J. Chin. Sci. Bull. 2008, 53, 1196.
15. Xu, N. J.; Fan, X.; Yan, X. J.; Li, X. C.; Niu, R. L.; Tseng, C. K. Phytochemistry 2003,
62, 1221.
16. Marco, H.; Beate, N.; Stammler, H.-G.; Kuck, D. Eur. J. Org. Chem. 2004, 2004,
2381.
glucose levels in the db/db mice by 33% and 40%, respectively. The
positive drug rosiglitazone showed 48.4% plasma glucose lowering
activity after six weeks treatment in similar conditions at a dose of
50 mg/kg. Furthermore, compound 4g also remarkably decreased
HbA1c levels at 25 and 50 mg/kg (P <0.01). The total cholesterol
concentration of both high and low dose of compound 4g was
significantly reduced after the intervention of two weeks com-
pared with baseline. Unfortunately, no significant changes of triac-
ylglycerol concentration were observed during the intervention
period (Table 4).
17. Kubo, I.; Ochi, M.; Shibata, K.; Hanke, F. J.; Nakatsu, T.; Tan, K.-S.; Taniguchi, M.;
Kamikawa, T.; Yamagiwa, Y.; Arizuka, M.; Wood, W. F. J. Nat. Prod. 1990, 53, 50.
18. Harrowven, D. C.; Bradley, M.; Lois Castro, J.; Flanagan, S. R. Tetrahedron Lett.
2001, 42, 6973.
19. Shoeib, N. A.; Bibby, M. C.; Blunden, G.; Linley, P. A.; Swaine, D. J.; Wheelhouse,
R. T.; Wright, C. W. J. Nat. Prod. 2004, 67, 1445.
20. West, C. T.; Donnelly, S. J.; Kooistra, D. A.; Doyle, M. P. J. Org. Chem. 1973, 38,
2675.
21. Chakrabarti, A.; Chawla, H. M.; Hundal, G.; Pant, N. Tetrahedron 2005, 61,
12323.
In summary, a series of bromophenol derivatives were designed
and synthesized for the discovery of potent PTP1B inhibitors. The
preliminary structure-activity relationship acquired show that (i)
the diarylmethane scaffold is favorable to PTP1B inhibitory activ-
ity, (ii) multi-bromine atoms (four to six) attached to the phenyl
ring is important for PTP1B inhibition. Among these, compound
4g exhibited remarkable inhibitory activity against PTP1B with
IC50 0.68
lmol/L, which was approximately four-fold potent than
22. Shultz, D. A.; Fico, R. M.; Bodnar, S. H.; Kumar, R. K.; Vostrikova, K. E.; Kampf, J.
W.; Boyle, P. D. J. Am. Chem. Soc. 2003, 125, 11761.
the lead compound 4e (IC50 = 2.42
l
mol/L). As an interesting en-
23. Experimental: Melting points were determined using Boetius electrothermal
capillary melting point apparatus and are uncorrected. IR (in cmÀ1) spectra in
KBr pellets on a IMPACT-400 spectrophotometer. 1H and 13C spectra were
recorded on an Inova (500 MHz) NMR spectrometer for proton and at 125 MHz
for carbon. Mass spectra were recorded on Autospec Ultima-Tof mass
spectrometer and Thermo LTQ-Orbitrap. Column chromatography was
carried out using silica gel (200–300 mesh). Thin-layer chromatography
(TLC) was performed on precoated silica gel 60 F254 plates. Solvents were
purchased from Shanghai Chemical Reagent Company and used without
further purification.
tity, compound 4g exhibited high selectivity against other PTPs
in vitro and promising antidiabetic activities in vivo. The chemical
entities reported in this study could provide a possible opportunity
for developing novel PTP1B inhibitors with promising selectivity
and pharmacological properties.
Acknowledgments
Procedures for the synthesis of compound 1a: 22.08 g (120 mmol) of 3,4-
dimethoxybenzoic acid 1 and 16.92 g (120 mmol) of 1,2-dimethoxybenzene 2
were stirred in 100 g of polyphosphoric acid at 80 °C for 1 h. The mixture was
then cooled to 60 °C, and 250 mL of water was added over 30 min. The
precipitate was filtered and dissolved in 100 mL CH2Cl2, washed with 3% NaOH
and water successively. The organic phase was dried over anhydrous Na2SO4
and concentrated in vacuo to give 30.7 g 1a, yield 85%.
We thank to the National Center for Drug Screening (Shanghai,
PR China) for providing data on PTP1B inhibitory activities of
compounds. This work was supported by National Major Research
Program of China ‘‘The Creation for Significant Innovative Drugs’’
(No. 2009ZX09103-148), the National Natural Science Foundation
of Shandong (No. BS2009YY011), the National Natural Science
Foundation of Qingdao (No. 10-3-4-8-2-JCH), and the Program of
Qingdao Shinan District (No. 2009-HY-2-14).
Analytic data for compound 1a: white powder, mp 145.3–246.1 °C (lit16 mp
147 °C). 1H NMR (500 MHz, CDCl3): d 3.92 (s, 6H), 3.94 (s, 6H), 6.88 (d, 2H,
J = 8.4 Hz), 7.36 (dd, 2H, J = 8.4, 1.7 Hz), 7.42 (d, 2H, J = 1.7 Hz). 13C NMR
(125 MHz, CDCl3): d 56.03, 109.79, 112.39, 124.69, 130.82, 148.90, 152.61,
194.35.
Procedures for the synthesis of compound 1b: To solution of compound 1a (3 g,
10 mmol) in CH2Cl2 (20 mL) was added bromine (0.56 mL in 10 mL CH2Cl2,
11 mmol) dropwise while stirring. The mixture was stirred at room
temperature. Thin Layer Chromatography (TLC) was used to monitor the
reaction end point. After the reaction, the mixture was concentrated in vacuo.
References and notes
1. Saltiel, A. R.; Kahn, C. R. Nature 2001, 414, 799.
2. Pei, Z.; Liu, G.; Lubben, T. H.; Szczepankiewicz, B. G. Curr. Pharm. Des. 2004, 10,
3481.
The residue was chromatographed on
a silica gel column (petroleum
3. Dadke, S.; Chernoff, J. Curr. Drug Targets 2003, 3, 299.
ether:acetone, 8:1) to afford 2.43 g 1b, yield 64%.
Analytic data for compound 1b: white powder, mp 129.9–230.5 °C. 1H NMR
(500 MHz, CDCl3): d 3.84 (s, 3H), 3.92 (s, 3H), 3.93 (s, 3H), 3.94 (s, 3H), 6.85 (d,
1H, J = 8.4 Hz), 6.87 (s, 1H), 7.07 (s, 1H), 7.25 (dd, 1H, J = 8.4, 1.9 Hz), 7.54 (d,
1H, J = 1.9 Hz). 13C NMR (125 MHz, CDCl3): d 56.05, 56.09, 56.19, 56.32, 110.01,
110.65, 111.37, 112.10, 115.81, 126.22, 129.58, 132.85, 148.25, 149.29, 150.66,
153.89, 194.25.
Procedures for the synthesis of compound 1c: To solution of 1a (15.1 g, 50 mmol)
in 120 mL acetic acid was added bromine (5.4 mL in 10 mL AcOH, 105 mmol)
dropwise while stirring. The mixture was stirred at room temperature. TLC was
used to monitor the reaction end point. Then the mixture was concentrated in
vacuo. The residue was dissolved in CHCl3 and washed with 5% NaHSO3, 3%
4. Hwa.-Ok Kim, M. A. B. Expert Opin. Ther. Pat. 2002, 12, 871.
5. Elchebly, M.; Payette, P.; Michaliszyn, E.; Cromlish, W.; Collins, S.; Loy, A. L.;
Normandin, D.; Cheng, A.; Himms-Hagen, J.; Chan, C. C.; Ramachandran, C.;
Gresser, M. J.; Tremblay, M. L.; Kennedy, B. P. Science 1999, 283, 1544.
6. Klaman, L. D.; Boss, O.; Peroni, O. D.; Kim, J. K.; Martino, J. L.; Zabolotny, J. M.;
Moghal, N.; Lubkin, M.; Kim, Y. B.; Sharpe, A. H.; Stricker-Krongrad, A.;
Shulman, G. I.; Neel, B. G.; Kahn, B. B. Mol. Cell. Biol. 2000, 20, 5479.
7. Johnson, T. O.; Ermolieff, J.; Jirousek, M. R. Nat. Rev. Drug Disc. 2002, 1, 696.
8. Taylor, S. D.; Hill, B. Expert Opin. Investig. Drugs 2004, 13, 199.
9. Chen, R. M.; Hu, L. H.; An, T. Y.; Li, J.; Shen, Q. Bioorg. Med. Chem. Lett. 2002, 12,
3387.

D. Shi et al. / Bioorg. Med. Chem. Lett. 22 (2012) 2827–2832
2831
NaOH and brine successively. The organic phase was dried over anhydrous
Na2SO4, and concentrated in vacuo to give 18.87 g 1c, yield 82%.
Analytic data for compound 1c: pale yellow powder, mp 172.5–273.2 °C. 1H
NMR (500 MHz, CDCl3): d 3.87 (s, 6H), 3.94 (s, 6H), 7.05 (s, 4H). 13C NMR
(125 MHz, CDCl3): d 56.26, 56.33, 113.22, 114.00, 116.37, 131.76, 148.40,
152.01, 194.26.
Procedures for the synthesis of compound 1d: To the suspension of compound 1c
(4.6 g, 10 mmol) and 1.0 g AlCl3 in 100 mL acetic acid was added bromine
(1 mL in 10 mL AcOH, 20 mmol) dropwise while stirring. The reaction mixture
was heated at 40 °C. After the reaction, the mixture was poured into 3% HCl and
extracted with CH2Cl2. The combined extracts were concentrated in vacuo and
6.79 (d, 1H, J = 8.0 Hz), 7.04 (s, 1H). 13C NMR (125 MHz, CDCl3): d 40.86 55.89,
55.93, 56.06, 56.21, 111.41, 112.32, 113.74, 114.51, 115.72, 120.76, 132.52,
132.60, 147.62, 148.21, 148.58, 149.07.
Analytic data for compound 3c: Yield 80%, white powder, mp 98.6–28.7 °C. 1H
NMR (500 MHz, CDCl3): d 3.74 (s, 6H), 3.86 (s, 6H), 4.06 (s, 2H), 6.59 (s, 2H),
7.05 (s, 2H). 13C NMR (125 MHz, CDCl3): d 40.94, 56.06, 56.20, 113.43, 114.55,
115.65, 131.31, 148.30, 148.61.
Analytic data for compound 3d: Yield 70%, white powder, mp 113.3–214.7 °C.
HRMS-EI
C
m/z:
measured
523.8660
([M]+,
calcd
523.8656
for
17H17O479Br281Br). MS-EI m/z (% relative intensity): 528/526/524/522 ([M]+,
51/100/100/52), 448/446/444 (5/10/7), 366/364 (91/90), 285 (23). IR (KBr):
3078, 2935, 2845, 1601, 1581, 1548, 1504, 1461, 1423, 1371, 1335, 1317, 1259,
the residue was chromatographed on
a silica gel column (petroleum
ether:EtOAc, 6:1) to afford 2.21 g 1d, yield 41%.
1219, 1191, 1163, 1053, 1032, 1008, 860, 841, 649, cmÀ1 1H NMR (500 MHz,
.
Analytic data for compound 1d: white powder, mp 160.8–261.3 °C. HRMS-EI m/
z: measured 537.8453 ([M]+, calcd 537.8449 for C17H15O579Br281Br). MS-EI m/z
(% relative intensity): 542/540/538/536 ([M]+, 17/43/45/17), 461/459/457 (3/5/
3), 380/378 (99/100), 325/323/321 (9/20/11), 245/243 (50/51). IR (KBr): 2926,
2842, 1653, 1585, 1506, 1463, 1420, 1374, 1302, 1259, 1204, 1159, 1074, 934,
CDCl3): d 3.71 (s, 3H), 3.77 (s, 3H), 3.83 (s, 3H), 3.88 (s, 3H), 4.15 (s, 2H), 6.54 (s,
1H), 6.62 (s, 1H), 7.07 (s, 1H). 13C NMR (125 MHz, CDCl3): d 43.13 56.16, 56.20,
56.20, 60.50, 113.32, 113.68, 114.86, 115.76, 117.71, 121.91, 130.61, 136.71,
146.35, 148.58, 148.73, 152.53.
Analytic data for compound 3e: Yield 73%, white powder, mp 149.9–250.2 °C. 1
H
882, 841, 654 cmÀ1
.
1H NMR (500 MHz, CDCl3): d 3.87 (s, 6H), 3.92 (s, 3H), 3.94
NMR (500 MHz, CDCl3): d 3.75 (s, 6H), 3.85 (s, 6H), 4.24 (s, 2H), 6.58 (s, 2H). 13
C
(s, 3H), 6.97 (s, 1H), 7.07 (s, 1H), 7.16 (s, 1H). 13C NMR (125 MHz, CDCl3): d
56.35, 56.39, 56.44, 60.76, 113.08, 114.32, 114.47, 114.67, 116.85, 123.05,
130.04, 137.84, 148.44, 149.69, 152.69, 152.74, 193.61.
NMR (125 MHz, CDCl3): d 45.29, 56.30, 60.54, 113.56, 118.02, 122.12, 136.00,
146.66, 152.65.
Procedures for the synthesis of compound 3f: To solution of compound 3e (6.0 g,
10 mmol) in 100 mL acetic acid was added 1.0 g AlCl3 at 45 °C. After 30 min,
0.6 mL bromine in 10 mL acetic acid was added dropwise while stirring at
room temperature. The reaction mixture was then heated at 70–20 °C (TLC
monitored). At the end, the mixture was poured into 3% HCl and extracted with
CH2Cl2. The organic extract was dried over anhydrous Na2SO4, and evaporated
in vacuo to provide the brownish residue. The residue was chromatographed
on a silica gel column (petroleum ether:EtOAc, 50:1) to afford 4.43 g 1e, yield
65%.
Procedures for the synthesis of compound 1e: To a suspension of compound 1c
(4.6 g, 10 mmol) and 1.0 g AlCl3 in 100 mL acetic acid was added excess
bromine (4 equiv) dropwise while stirring at room temperature. The mixture
was heated at 80 °C and TLC was used to monitor the reaction end point. After
the reaction, the mixture was poured into 3% HCl and extracted with CH2Cl2.
The combined extracts were concentrated in vacuo and the residue was
chromatographed on a silica gel column (petroleum ether:EtOAc, 8:1) to afford
3.17 g 1e, yield 51%.
Analytic data for compound 1e: pale yellow powders, mp 120.7–221.4 °C.
Analytic data for compound 3f: white powder, mp 160.8–261 °C. HRMS-EI m/z:
measured 680.6754 ([M+H]+, calcd 680.6763 for C17H14O479Br381Br2). 1H NMR
(500 MHz, CDCl3): d 3.62(s, 3H), 3.83 (s, 3H), 3.92 (s, 3H), 3.95 (s, 3H), 4.55 (s,
2H), 6.13 (s, 1H). 13C NMR (125 MHz, CDCl3): d 46.54 (t), 56.40 (q), 60.52 (q),
60.89 (q), 60.98 (q), 111.82 (d), 117.95 (s), 121.49 (s), 121.86 (s), 122.04 (s),
123.63 (s), 134.03 (s), 136.40 (s), 146.54 (s), 150.93 (s), 151.24 (s), 152.53 (s).
Procedures for the synthesis of compound 3g: To the suspension of compound 3e
(6.0 g, 10 mmol) in 50 mL con.H2SO4 was added NBS (3.6 g, 20 mmol) under
ice-bath, and the mixture was stirred at room temperature. TLC was used to
monitor the reaction end point. The mixture was poured into 100 mL ice-cold
water and extracted with CH2Cl2 (3 Â 100 mL). The combined extracts were
washed with brine and dried over anhydrous Na2SO4, and evaporated in vacuo
to provide the brownish residue. The residue was purified by silica gel column
chromatography (petroleum ether:EtOAc, 50:1) to afford 7.09 g 3g, yield 93%.
Analytic data for compound 3g: white powder, mp 123–224 °C. 1H NMR
(500 MHz, CDCl3): d 3.87 (s, 6H), 3.90 (s, 6H), 4.91 (s, 2H). 13C NMR (125 MHz,
CDCl3): d 47.68 (t), 60.78 (q), 60.93 (q), 121.76 (s), 121.99 (s), 123.27 (s), 136.04
(s), 150.58 (s), 150.64 (s).
General procedures for the synthesis of compounds 2a–g and 4a–g: Compounds
1a–g and 3a–g (10 mmol) was dissolved in 30 mL dry dichloromethane, then
40 mL BBr3 (1 mol/L in CH2Cl2) was added dropwise while stirring in ice bath.
The reaction mixture stirred for further 4 h at room temperature. Then the
solution was poured into ice-cold water and extracted with EtOAc (3 Â 60 mL).
The organic extracts was dried over anhydrous Na2SO4, and evaporated in
vacuo to provide the brownish residue. The residue was purified by silica gel
column chromatography (CHCl3:MeOH, 15:1) to afford corresponding
compounds 2a–g and 4a–g.
HRMS-EI
C
m/z: measured
617.7537
([M]+,
calcd
617.7534
for
17H14O579Br281Br2). MS-EI m/z (% relative intensity): 622/620/618/616/614
([M]+, 4/26/34/26/3), 541/539/537/535 (2/4/4/2), 460/458/456 (52/100/52),
379/377 (5/4), 325/323/321 (32/63/36). IR (KBr): 3197, 2940, 2872, 1684,
1576, 1465, 1419, 1368, 1304, 1261, 1205, 1162, 1096, 1049, 1001, 850, 825,
632 cmÀ1 1H NMR (500 MHz, CDCl3): d 3.86 (s, 6H), 3.91 (s, 6H), 7.03 (s, 2H).
.
13C NMR (125 MHz, CDCl3): d 56.55, 60.81, 114.01, 115.24, 123.56, 136.34,
150.33, 152.48, 193.55.
Procedures for the synthesis of compound 1f: To the suspension of compound 1e
(6.2 g, 10 mmol) in 50 mL acetic acid and 150 mL con.H2SO4 was added NBS
(1.8 g, 10 mmol) under ice-bath, and the mixture was stirred for further 2 h at
room temperature. The mixture was poured into 200 mL ice-cold water and
extracted with CH2Cl2 (3 Â 300 mL). The combined extracts were washed with
brine and dried over anhydrous Na2SO4, and evaporated in vacuo to provide
the brownish residue. The residue was purified by silica gel column
chromatography (petroleum ether:EtOAc, 50:1) to afford 3.01 g 1f, yield 43%.
Analytic data for compound 1f: white powder, mp 113.3–214.7 °C. HRMS-EI m/z:
measured 696.6701 ([M+H]+, calcd 696.6712 for C17H14O579Br381Br2). MS-EI m/
z (% relative intensity): 700/698/696/694 ([M]+, 18/37/37/20), 540/538/536/
534 (22/67/68/22), 460/458/456 (52/100/52), 405/403/401/399 (10/16/30/32),
325/323/321 (50/100/51). 1H NMR (500 MHz, CDCl3): d 3.84 (s, 3H), 3.90 (s,
3H), 3.92 (s, 3H), 3.94 (s, 3H), 7.36 (s, 1H); 13C NMR (125 MHz, CDCl3): d 56.48
(q), 60.77 (q), 61.11 (q), 61.16 (q), 115.32 (d), 115.82 (d), 117.51 (s), 117.63 (d),
122.27(s), 124.79(s), 132.22 (s), 139.09 (s), 151.75 (s), 152.11 (s), 152.92 (s),
190.17 (s).
Procedures for the synthesis of compound 1g: To the suspension of compound 1e
(6.2 g, 10 mmol) in 50 mL concd H2SO4 was added NBS (3.6 g, 20 mmol) under
ice-bath, and the mixture was stirred for further 2 h at room temperature. TLC
was used to monitor the reaction end point. The mixture was poured into
100 mL ice-cold water and extracted with CH2Cl2 (3 Â 100 mL). The combined
extracts were washed with brine and dried over anhydrous Na2SO4, and
evaporated in vacuo to provide the brownish residue. The residue was purified
by silica gel column chromatography (petroleum ether:EtOAc, 50:1) to afford
7.37 g 1g, yield 95%.
Analytic data for compound 2a: Yield 91%, yellow powder, mp 224.3–225.2 °C.
1H NMR (500 MHz, DMSO-d6): d 6.81 (d, 2H, J = 8.2 Hz) 7.04 (dd, 2H, J = 8.2,
2.1 Hz), 7.15 (d, 2H, J = 2.1 Hz), 9.31 (s, 2H), 9.70 (s, 2H). 13C NMR (125 MHz,
DMSO-d6): d 114.78, 116.80, 122.47, 129.26, 144.76, 149.53, 193.08.
Analytic data for compound 2b: Yield 89%, yellow powder, mp 83.5–24.2 °C.
HRMS-EI m/z: measured 323.9649 ([M]+, calcd 323.9633 for C13H9O5Br). MS-EI
m/z (% relative intensity): 326/324 ([M]+, 70/70), 245 (77), 217/215 (43/45),
137 (100). IR (KBr): 3236, 2981, 2879, 1640, 1587, 1506, 1442, 1418, 1365,
Analytic data for compound 1g: white powder, mp 140–242 °C. HRMS-EI m/z:
measured 772.5835 ([M+H]+, calcd 772.5837 for C17H13O579Br581Br). MS-EI m/z
(% relative intensity): 780/778/776/774/772 ([M]+, 25/32/48/32/25), 618/616/
614 (67/100/67), 405/403/401/399 (25/81/81/25). 1H NMR (500 MHz, CDCl3): d
3.87 (s, 6H), 3.95 (s, 6 H). 13C NMR (125 MHz, CDCl3): d 60.93 (q), 61.10 (q),
119.32(s), 120.66(s), 123.23(s), 136.61 (s), 150.89 (s), 153.78 (s), 189.25(s).
General procedures for the synthesis of compounds 3a–e: To stirred solutions of
the compounds 1a–e (10 mmol) in 20 mL trifluoroactic acid was added
triethylsilane (22 mmol, 2.2 equiv). The mixture was stirred at room
temperature and TLC was used to monitor the reaction end point. After the
reaction, the mixture was poured into ice-cold water and extracted 3 times
with 60 mL of CH2Cl2. The combined organic extracts were concentrated in
vacuo to afford corresponding compounds 3a–e.
1289, 1186, 1111, 1046, 952, 881, 827, 636 cmÀ1 1H NMR (500 MHz, DMSO-
.
d6): d 6.71 (s, 1H), 6.80 (d, 1H, J = 8.3 Hz), 6.99 (s, 1H), 7.03 (dd, 1H, J = 8.3,
2.0 Hz), 7.16 (d, 1H, J = 2.0 Hz), 9.40 (s, 1H), 9.52 (s, 1H), 9.79 (s, 1H), 9.94 (s,
1H). 13C NMR (125 MHz, DMSO-d6): d 107.28, 115.24, 115.97, 116.56, 119.26,
123.38, 128.07, 131.36, 144.58, 145.14, 147.65, 151.14, 193.21.
Analytic data for compound 2c: Yield 89%, white powder, mp 245.6–245.9 °C.
HRMS-EI m/z: measured 403.8708 ([M]+, calcd 403.8718 for C13H8O579Br81Br).
MS-EI m/z (% relative intensity): 406/404/402 ([M]+, 18/36/19), 326/324 (13/
14), 244 (100), 217/215 (70/73). IR(KBr): 3177, 2978, 2871, 1653, 1585, 1505,
1419, 1286, 1182, 1047, 882, 634 cmÀ1 1H NMR (500 MHz, DMSO-d6): d 6.82
.
(s, 2H), 7.00 (s, 2H), 9.56 (s, 2H), 10.09 (s, 2H). 13C NMR (125 MHz, DMSO-d6): d
109.57, 118.25, 120.24, 129.79, 144.55, 149.34, 192.88.
Analytic data for compound 2d: Yield 90%, light yellow oil. HRMS-EI m/z:
measured 481.7807 ([M]+, calcd 481.7823 for C13H7O579Br281Br). MS-EI m/z (%
relative intensity): 486/484/482/480 ([M]+, 12/32/34/12), 324/322 (98/100),
297/295/293 (17/38/22), 244 (49), 217/215 (72/79). IR(KBr): 3177, 2957, 2876,
Analytic data for compound 3a: Yield 73%, white powder, mp 70.4–21.3 °C (lit16
68–29 °C). 1H NMR (500 MHz, CDCl3): d 3.83 (s, 6H), 3.85 (s, 6H), 3.88 (s, 2H),
6.69 (dd, 2H, J = 7.6, 1.9 Hz), 6.72 (d, 2H, J = 1.9 Hz), 6.79 (d, 2H, J = 7.6 Hz). 13
C
NMR (125 MHz, CDCl3): d 40.96, 55.82, 55.91, 111.43, 112.35, 120.77, 133.94,
147.49, 149.02.
1662, 1588, 1505, 1464, 1393, 1335, 1282, 1210, 1050, 884, 667 cmÀ1 1H NMR
.
(500 MHz, DMSO-d6): d 6.81 (s, 1H), 6.85 (s, 1H), 7.01 (s, 1H), 9.57 (s, 1H), 10.20
(s, 2H), 10.35 (s, 1H). 13C NMR (125 MHz, DMSO-d6): d 110.34, 111.81, 114.41,
115.38, 118.99, 120.72, 128.29, 132.24, 144.50, 144.76, 146.77, 150.01, 192.50.
Analytic data for compound 2e: Yield 88%, yellow powder, mp 233.0–233.1 °C.
Analytic data for compound 3b: Yield 75%, white powder, mp 74.5–24.9 °C. 1H
NMR (500 MHz, CDCl3): d 3.76 (s, 3H), 3.83 (s, 3H), 3.85 (s, 3H), 3.86 (s, 3H),
3.99 (s, 2H), 6.64 (s, 1H) 6.69 (dd, 1H, J = 8.0, 1.9 Hz), 6.73 (d, 1H, J = 1.9 Hz),

2832
HRMS-EI
D. Shi et al. / Bioorg. Med. Chem. Lett. 22 (2012) 2827–2832
calcd 561.6908 for HRMS-EI m/z: measured
m/z:
measured
561.6892
([M]+,
547.7101
([M]+,
calcd
547.7115
for
C
13H6O579Br281Br2). MS-EI m/z (% relative intensity): 566/564/562/560/558
C
13H8O479Br281Br2). MS-EI m/z (% relative intensity): 552/550/548/546/544
([M]+, 5/23/36/24/5), 485/483/481/479 (7/14/14/5), 404/402/400 (51/100/52),
324/322 (23/24), 297/295/293 (47/98/53). IR(KBr): 3167, 2977, 2878, 1652,
([M]+, 7/24/35/26/8), 390/388/386(50/100/52), 311/309 (50/50). 1H NMR
(500 MHz, DMSO-d6): d 3.95 (s, 2H), 6.49 (s, 2H), 9.47 (s, 2H), 9.95 (s, 2H).
13C NMR (125 MHz, DMSO-d6): d 43.59, 113.37 114.97, 115.72, 130.50, 143.17,
145.19.
1591, 1569, 1464, 1394, 1280, 1213, 1078, 1047, 865, 646 cmÀ1 1H NMR
.
(500 MHz, DMSO-d6): d 6.88 (s, 2H), 10.38 (s, 4H). 13C NMR (125 MHz, DMSO-
d6): d 112.65, 114.99, 116.28, 131.02, 144.60, 147.46, 192.48.
Analytic data for compound 4f: Yield 90%, yellow powder, mp 139–240 °C.
HRMS-EI m/z: measured 624.6140 ([MÀH]À, calcd 624.6137 for
C13H6O479Br381Br2). 1H NMR (500 MHz, DMSO): d 4.27(s, 2H), 6.04 (s, 1H),
9.39 (s, 1H), 9.77 (s, 1H), 9.90 (s, 1H), 10.04 (s, 1H). 13C NMR (125 MHz, DMSO):
d 45.23 (t), 113.24 (s), 113.24 (s), 113.91 (s), 114.13 (d), 114.41 (s), 117.04 (s),
128.56 (s), 129.99 (s), 142.87 (s), 143.95 (s), 144.24 (s), 145.07 (s).
Analytic data for compound 4g: Yield 91%, yellow powder; mp 225–226 °C.
HRMS-EI m/z: measured 704.5218 ([M]À, calcd 704.5221 for
Analytic data for compound 2f: Yield 90%, white powder, mp 118–220 °C.
HRMS-EI m/z: measured 639.5931 ([MÀH]À, calcd 638.5929 for
C
13H5O579Br381Br2). MS-EI m/z (% relative intensity): 644/642/640/638 ([M]+,
2/4/4/2), 484/482/480/478 (4/10/10/4), 375/373 (5/7), 297/295/293 (5/13/7).
1H NMR (500 MHz, DMSO): d = 7.05 (s, 1H)ppm. 13C NMR (125 MHz, DMSO):
d = 108.41 (s), 111.60(d),114.44(s), 115.57(s), 117.34(s), 118.92(s), 126.85(s),
134.13(s), 144.44(s), 144.77(s), 146.62(s), 149.70(s), 190.20(s) ppm.
Analytic data for compound 2g: Yield 90%, pale powder, mp 220–222 °C. HRMS-
EI m/z: measured 718.5014 ([MÀH]À, calcd 708.5014 for C13H4O579Br381Br3).
MS-EI m/z (% relative intensity): 722/720/718 ([M]+, 2/4/2), 562/560/558 (5/10/
5), 516/514 (6/4), 377/375/373/371 (3/12/12/3). 1H NMR (500 MHz, DMSO-d6):
d 10.12 (s, 2H),10.23 (s, 2H). 13C NMR (125 MHz, CDCl3): d 111.90 (s), 114.76
(s), 115.26 (s), 131.63 (s), 143.65 (s), 147.57 (s), 189.81 (s).
C
13H5O479Br381Br3). 1H NMR (DMSO-d6, 500 MHz): d 4.69 (s, 2H), 9.68 (s,
2H), 9.85 (s, 2H); 13C NMR (DMSO-d6, 125 MHz): d 46.61 (t), 114.24 (s), 114.49
(s), 116.93 (s), 130.15 (s), 143.55 (s), 143.60 (s).
24. Enzyme activity assay in vitro: The derivatives were assessed against PTP1B
with the colorimetric assay. Compounds were solubilized in DMSO, and
samples were distributed to 96-well clear polystyrene plate. DMSO was
distributed as the full enzyme activity. After adding an assay mixture, GST-
PTP1B was added to initiate the reaction. The high-throughput screening was
carried out in a mixture containing MOPS, pNPP, PTP1B and DMSO, and the
catalysis of pNPP was continuously monitored at 405 nm for 2 min at 30 °C.
Analytic data for compound 4a: Yield 93%, pink powder, mp 181.3–282.1 °C. 1
H
NMR (500 MHz, DMSO-d6): d 3.55 (s, 2H), 6.41 (dd, 2H, J = 7.9, 1.8 Hz), 6.51 (d,
2H, J = 1.8 Hz), 6.61 (d, 2H, J = 7.98 Hz) 8.57 (s, 2H), 8.70 (s, 2H). 13C NMR
(125 MHz, DMSO-d6): d 39.85, 115.31, 115.99, 119.17, 132.74, 143.19, 144.94.
Analytic data for compound 4b: Yield 96%, brown powder, mp 128.7–229.1 °C.
HRMS-EI m/z: measured 309.9834 ([M]+, calcd 309.9841 for C13H11O4Br). MS-
EI m/z (% relative intensity): 312/310 ([M]+, 53/54), 231 (52), 213 (100), 123
(27). IR(KBr): 3328, 2981, 2878, 1602, 1506, 1431, 1354, 1279, 1191, 1140,
Inhibitory rate was calculated according to the fomula:
100 Â (VDMSO À Vsample)/VDMSO The IC50 value was calculated from the
% inhibition =
.
nonlinear curve fitting of the percent inhibition [inhibition (%)] versus the
inhibitor concentration [I] using the following equation:% inhibition = 100/
{1 + (IC50/[I])k}, where k is the Hill coeffcient. In experiments to determine the
selectivity over PTPases, the enzymatic systems for other PTPases were the
same as it for PTP1B. These enzymes and inhibitors were preincubated for
3 min at 4 °C, and the assays were initiated by adding substrates. Assays
performed for SHP1 and SHP2, and LAR were done using OMFP as a substrate.
25. Antidiabetic activity in db/db mice
1109, 1045, 879, 820, 639 cmÀ1 1H NMR (500 MHz, DMSO-d6): d 3.68 (s, 2H),
.
6.42 (d, 1H, J = 8.0 Hz), 6.52 (s, 1H), 6.58 (d, 1H, J = 1.9 Hz), 6.63 (dd, 1H, J = 8.0,
1.9 Hz), 6.90 (s, 1H), 8.63 (s, 1H), 8.75 (s, 1H), 9.08 (s, 1H), 9.18 (s, 1H). 13C NMR
(125 MHz, DMSO-d6): d 39.19, 111.37, 115.44, 115.96, 117.76, 118.78, 119.34,
130.99, 130.99, 143.44, 144.77, 145.01, 145.04.
Analytic data for compound 4c: Yield 94%, brown oil. HRMS-EI m/z: measured
389.8924 ([M]+, calcd 389.8925 for C13H10O479Br81Br). MS-EI m/z (% relative
intensity): 392/390/388 ([M]+, 34/66/35), 311/309 (7/7), 230 (100). IR (KBr):
3315, 2981, 2877, 1600, 1505, 1429, 1342, 1275, 1224, 1186, 1142, 1046, 872,
C57BL/Ks db/db mice 8 weeks, 40–50 g bred in the animal house of China
Pharmaceutical University. The mice were housed in groups of four (same sex)
in a room controlled for temperature (23 2.0 °C) and 12/12 h light/dark cycle
(lights on at 6.00 am). After a 2-week adaptation period, the 10-week-old mice
were divided into four groups (n = 8 in each group), the model (0.5% sodium
carboxyl methyl cellulose) group, rosiglitazone group (50 mg/kg), compound
4g high-dose group (50 mg/kg) and compound 4g low-dose group (25 mg/kg).
Rosiglitazone and compound 4g were dissolved in 0.5% sodium carboxyl
methyl cellulose solution and administered orally for six weeks. Body weight
was measured weekly from week 1 to week 6. All animals had free access to
fresh water and to normal chow. Postprandial blood glucose was checked with
an ONE TOUCHÒ UltraÒ glucometer (LifeScan, USA) weekly and triacylglycerols
and total cholesterol (Whitman Biotech Co., Ltd, Nanjing, China) were checked
by an enzymatic method twice a week. The mice were fasted overnight on
week 6 and glycosylated hemoglobin levels were measured by HbA1c reagent
(Whitman Biotech Co., Ltd, Nanjing, China).
818, 636 cmÀ1 1H NMR (500 MHz, DMSO-d6): d 3.74 (s, 2H), 6.44 (s, 2H), 6.93
.
(s, 2H) 9.13 (s, 2H), 9.34 (s, 2H). 13C NMR (125 MHz, DMSO-d6): d 39.18, 111.55,
117.34, 118.89, 129.15, 144.91, 145.00.
Analytic data for compound 4d: Yield 90%, white powder, mp 190.9–291.4 °C.
HRMS-EI m/z: measured 467.8007 ([M]+, calcd 467.8030 for C13H9O479Br281Br).
MS-EI m/z (% relative intensity): 472/470/468/466 ([M]+, 12/33/34/13), 310/
308 (97/100), 229 (65). IR(KBr): 3330, 2955, 2925, 1599, 1506, 1465, 1429,
1405, 1342, 1274, 1222, 1181, 1147, 1047, 856, 824, 637 cmÀ1 1H NMR
.
(500 MHz, DMSO-d6): d 3.84 (s, 2H), 6.45 (s, 1H), 6.48 (s, 1H), 6.95 (s, 1H), 9.16
(s, 1H), 9.24 (s, 1H), 9.42 (s, 1H), 9.91 (s, 1H). 13C NMR (125 MHz, DMSO-d6): d
41.61, 111.70, 113.28, 114.80, 115.71, 117.36, 118.98, 128.72, 130.92, 143.03,
145.07, 145.07, 145.15.
Analytic data for compound 4e: Yield 91%, yellow powders, mp 199.0–299.8 °C.