Synthesis of chiral ND-322, ND-364 and ND-364 derivatives as selective inhibitors of human gelatinase

Article abstract of DOI:10.1016/j.bmc.2015.09.013

Compounds 10 (ND-322) and 15 (ND-364) are potent selective inhibitors for gelatinases, matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9). However, both of them are racemates. Herein we report facile synthesis of optically active (R)-

Full text of DOI:10.1016/j.bmc.2015.09.013

Bioorganic & Medicinal Chemistry 23 (2015) 6632–6640
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis of chiral ND-322, ND-364 and ND-364 derivatives as
selective inhibitors of human gelatinase
a,
Yugang Yan a, Xueying Chen b, Xinying Yang c, Jian Zhang d, Wenfang Xu a, , Yingjie Zhang
⇑
⇑
a Institute of Medicinal Chemistry, School of Pharmacy, Shandong University, Ji’nan 250012, PR China
b The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Shandong University,
Qilu Hospital, No. 107, Wen Hua Xi Road, Ji’nan 250012, PR China
c Institute of Pharmaceutical Analysis, School of Pharmacy, Shandong University, Ji’nan 250012, PR China
d Department of Medical Chemistry, School of Pharmacy, Weifang Medical University, 7166, West Baotong Road, Weifang, Shandong 261042, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 26 July 2015
Revised 5 September 2015
Accepted 6 September 2015
Available online 7 September 2015
Compounds 10 (ND-322) and 15 (ND-364) are potent selective inhibitors for gelatinases, matrix metal-
loproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9). However, both of them are racemates.
Herein we report facile synthesis of optically active (R)- and (S)-enantiomers of compounds 10 and 15.
And the sulfonyl of 15 was transformed to sulfinyl to obtain four epimeric mixtures. All synthesized thi-
irane-based compounds were evaluated in MMP2 and MMP9 inhibitory assays. Our results indicated that
the configuration of thiirane moiety had little effects on gelatinase inhibition, but the substitution of sul-
finyl for sulfonyl was detrimental to gelatinase inhibition. Besides, all target compounds exhibited no
inhibition against other two Zn2+ dependant metalloproteases, aminopeptidase N (APN) and histone
deacetylases (HDACs), which confirmed the unique Zn2+ chelation mechanism of thiirane moiety against
gelatinases.
Keywords:
Chiral
MMP2
MMP9
ND-322
N-364
Ó 2015 Elsevier Ltd. All rights reserved.
Sulfoxide
CD
1. Introduction
collagenases (MMP1, MMP8 and MMP13), gelatinases (MMP2
and MMP9), stromelysins (MMP3, MMP7, MMP10, MMP11 and
Matrix metalloproteinases (MMPs) are zinc-dependent
endopeptidases that regulate functions of the extracellular matrix
(ECM),1 which are implicated in cancer growth,2–4 tumor metasta-
sis and angiogenesis,5–7 arthritis,8,9 connective tissue diseases,10,11
inflammation,12 cardiovascular,13,14 neurological,15,16 and autoim-
mune diseases.17,18 To date, MMPs constitute more than 26 sub-
family members and can be grouped into five classes:
MMP12), membrane-type MMPs (MT1-MMP, MT2-MMP, MT3-
MMP and MT4-MMP), and other enzymes.19,20 Of these enzymes,
gelatinases A (MMP2) and B (MMP9) are implicated in many dis-
eases, and selective inhibitors for gelatinases are highly sought.
Recently, compounds with thiirane moiety for human gelati-
nases are discovered. These compounds are selective against
gelatinases due to their unique mechanism of action: enzyme inhi-
bition occurs by Glu404-dependent deprotonation at the methy-
lene adjacent to the sulfone, initiating ring opening of the
thiirane and formation of
a
stable zinc–thiolate complex21
Abbreviations: MMP2, matrix metalloproteinase 2; MMP9, matrix metallopro-
teinase 9; APN, aminopeptidase N; HDACs, histone deacetylases; MMPs, matrix
metalloproteinases; ECM, extracellular matrix; CEs, Cotton effects; PTSC, para-
toluenesulfonyl chloride; DCM, dichloromethane; TEA, triethylamine; DMF,
dimethyl formamide; THF, tetrahydrofuran; Zn, zinc powder; AcOH, acetic acid;
MeOH, methanol; (Boc)2O, di-tert-butyl dicarbonate; Ti(O-i-Pr)4, tetra isopropyl
titanate; (CHPO, 80%), 80% cumene hydroperoxide; EtOAc, ethyl acetate; MgSO4,
(Fig. 1A). Among these inhibitors ND-32222 (Fig. 1B) with modifi-
able 4-substituted phenoxy-aniline is a potent inhibitor in many
scientific investigations,22–24 and its N-acetylated metabolite ND-
364 (Fig. 1C) was even more potent.24 It should be mentioned that
both ND-322 and ND-364 are racemates. Herein, in order to inves-
tigate the effects of configuration of thiirane moiety on gelatinases
inhibition, the optically active (R)-and (S)-enantiomers of com-
pounds ND-322 and ND-364 were synthesized and evaluated.
Moreover, sulfonyl group of ND-364 was transformed to sulfinyl
to find novel gelatinases inhibitors.
anhydrous magnesium sulfate;
tartrate.
D
-DET, (À)-diethyl
D-tartrate; L-DET, diethyl-L-
⇑
Corresponding authors. Tel./fax: +86 531 88382264 (W.X.), +86 531 88382009
(Y.Z.).
E-mail addresses: wenfxu@gmail.com (W. Xu), zhangyingjie@sdu.edu.cn
(Y. Zhang).
http://dx.doi.org/10.1016/j.bmc.2015.09.013
0968-0896/Ó 2015 Elsevier Ltd. All rights reserved.

Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
6633
A
O
O
Glu404
Glu404
Zn2+
O
HO
O
O
H
H
H
S
O
S
S
Zn2+
S
O
O
O
His
His
His
SB-3CT
His
His
His
C
B
O
O
O
H2N
S
N
H
S
S
S
O
O
O
O
ND-322
ND-364
Figure 1. (A) The unique mechanism: enzyme inhibition occurs by Glu404-dependent deprotonation at the methylene adjacent to the sulfone, initiating ring opening of the
thiirane and formation of a stable zinc–thiolate complex. (B) The structure of ND-322. (C) The structure of ND-364.
to the same procedure as compound 13, using (S)-oxiran-2-yl-
methanol and oxiran-2-ylmethanol as the starting materials,
respectively. The optical purity of 13 and 14 was comparative
(Table 1). Compound 15, namely ND-364, was synthesized as con-
trol drug.
In Scheme 3, compound 16 was synthesized with catalyst (Ti(O-
i-Pr)4), ligand (D-DET) and oxidant (CHPO, 80%). When the reaction
was over, the mixture was immediately purified by flash column
chromatography with ethyl acetate to quench reaction. Then, thi-
irane ring formation with thiourea involving inversion of stereo-
chemistry gave compound 18.25
Compound 19 was synthesized according to the same proce-
dure as compound 18, with the sole substitution of diethyl-L-
tartrate as the ligand of choice. Compounds 20 and 21 were
synthesized according to the same procedure as compound 18
and 19, respectively, with the sole substitution of (S)-oxiran-2-yl-
methanol as the reagent of choice.
2. Chemistry
In Scheme 1, synthesis commences with chlorosulfonation of
(R)-oxiran-2-ylmethanol (98.0% ee) (1) to get (S)-oxiran-2-ylmethyl
4-methylbenzenesulfonate (2), which was then treated with
4-mercaptophenol to generate compound 3. The nucleophilic attack
of the thioalcohol occurred exclusively at the C-3 of compound 2
and the stereocenter was not scrambled during this step.25 Forma-
tion of the epoxide ring and reacting with 1-fluoro-4-nitrobenzene
took place in one step in the presence of Cs2CO2. The nitro was
reduced by zinc powder, then filtered by kieselguhr with the filtrate
without further purification being added (Boc)2O for protecting
amino group. Followed by three steps (sulfide oxidation, thiirane
ring formation and N-Boc deprotection), the title compound 8
was prepared. The penultimate step, conversion of the oxirane to
the thiirane ring, involved inversion of stereochemistry.25
Compounds
(R)-4-(4-((thiiran-2-ylmethyl)sulfonyl)phenoxy)
aniline hydrochloride (9) and 4-(4-((thiiran-2-ylmethyl)sulfonyl)
phenoxy)aniline hydrochloride (10) were synthesized according
to the same procedure as compound 8, using (S)-oxiran-2-yl-
methanol and oxiran-2-ylmethanol as the starting materials,
respectively. The optical purity of 8 and 9 was comparative
(Table 1). Compound 10, namely ND-322, was synthesized as con-
trol drug.
In Scheme 2, reduction of intermediate 4 followed by N-acety-
lation led to compound 11, which was transformed to compound
13 in two steps: sulfide oxidation and thiirane ring formation.
The conversion of the oxirane to thiirane ring also involved inver-
sion of stereochemistry.25
3. Results and discussion
To determine the stereochemistry of chiral sulfoxide sulfur of
18, 19, 20 and 21, the Cotton effects of products 18, 19, 20 and
21 with the same concentration (200 lg/mL) in acetonitrile were
measured by Chirascan CD Spectrometer (Fig. 2A and B). Because
of the lack of previously investigated CD data of similar samples,
there was no possibility for the interpretation of the CD spectra
of such phenyl methyl sulfoxide—thiirane hybrids directly by an
empirical comparison. Considering that the products 18, 19, 20
and 21 are a conjugate of phenyl methyl sulfoxide moiety with thi-
irane moiety, and there were only two stereoelements in the struc-
tures, the addition of the CD spectra of the two molecular moieties
possibly resulted in the overall CD spectra of 18, 19, 20 and 21.
Compounds
(R)-N-(4-(4-((thiiran-2-ylmethyl)sulfonyl)phe-
noxy)phenyl)acetamide (14) and N-(4-(4-((thiiran-2-ylmethyl)sul-
fonyl)phenoxy)phenyl)acetamide (15) were synthesized according
HO
O
O
a
b
c
d
OH
OTs
O
O
S
OTs
O2N
S
BocHN
S
O
O
OH
5
2
3
4
1
O
O
O
e
g
f
BocHN
S
O
BocHN
S
H2N
HCl
S
O O
O
S
S
O
O
O
6
7
8
Scheme 1. Reagents and conditions: (a) PTSC, TEA, DCM, 0 °C, 85.0%; (b) 4-mercaptophenol, TEA, DCM, 0 °C, 81.5%; (c) 1-fluoro-4-nitrobenzene, Cs2CO2, DMF, rt, 83.0%; (d) Zn,
AcOH, THF, 0 °C, (Boc)2O, TEA, MeOH, 0 °C–rt, 81.1%; (e) Ti(O-i-Pr)4, CHPO (80%), DCM, rt, 87.3%; (f) thiourea, DCM, MeOH, rt, 84.5%; (g) HCl, anhydrous EtOAc, rt, 89.0%, 96.2%
ee.

6634
Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
Table 1
The inhibitory activities of the target compounds against MMP2, MMP9, APN and HDACs
c
c
Compounds
Stereo ee a or dra MMP2 (IC50
(nM)
)
MMP9 (IC50
(nM)
)
MMP2 %
inhib.d
MMP9 %
inhib.d
APN %
inhib.d
HDACs %
inhib.d
O
(S)
(R)
( )
96.2%
96.2%
235.2
144.6
63.6
709.7
833.0
611.0
97.7
100
100
98.3
97.4
96.7
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
H2N
HCl
S
S
S
S
S
O
O
O
O
8
O
H2N
HCl
O
9
O
H2N
HCl
S
O
10
O
O
(S)
92.9%
93.6%
256.2
299.2
170.0
ND
677.2
428.6
529.1
ND
92.6
100
100
30.7
7.9
91.1
96.2
97.2
23.7
3.4
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
n.i.
N
H
S
S
S
S
S
O
O
O
O
13
O
O
(R)
N
H
S
S
O
O
14
O
O
( )
N
H
15
O
O
(S, S)
(R, S)
(S, R)
(R, R)
23:76:1b
60:38:2b
1:67:32b
2:27:71b
N
H
S
O
18
O
O
ND
ND
N
H
S
O
S
S
19
O
O
ND
ND
12.9
34.4
N
H
S
O
20
O
O
ND
ND
14.1
24.8
N
H
S
O
S
21
NNGH
Bestatin
SAHA
2.0
ND
ND
5.9
ND
ND
100
ND
ND
100
ND
ND
ND
6.9e
ND
ND
ND
176.6f
ND: not determined.
n.i.: no inhibition.
a
Assayed by chiral HPLC.
b
c
d
e
f
Corresponding compound is the main component.
IC50 values are mean of three experiments, the standard derivations are <20% of the mean.
The inhibitory potency was determined at 10 M concn of the compounds. % inhibition values are reported as mean of three experiments.
The IC50 of Bestatin, unit is m, the standard derivations are <20% of the mean.
l
l
The IC50 of SAHA, unit is nM, the standard derivations are <20% of the mean.
O
O
O
b
a
O
O
c
O
4
N
H
S
N
H
S
N
H
S
O O
O
S
O
O
O
12
13
11
Scheme 2. Reagents and conditions: (a) Zn, AcOH, THF, 0 °C, acetyl chloride, TEA, MeOH, 0 °C–rt, 78.1%; (b) Ti(O-i-Pr)4, CHPO (80%), DCM, rt, 91.0%; (c) thiourea, THF, MeOH,
rt, 92.5%, 92.9% ee.
Thus, it seemed appropriate to compare the overall CD spectra of
18, 19, 20 and 21 with the experimental CD spectra of the corre-
sponding moieties. It was reported that phenyl methyl sulfoxide
showed two Cotton effects (CEs) with the kmax based on CD was
at 212 nm and 235 nm. The R isomer of phenyl methyl sulfoxide
showed a negative Cotton effect around 212 nm and a positive
Cotton effect around 235 nm; meanwhile, The S isomer of phenyl
methyl sulfoxide showed a positive Cotton effect around 212 nm
and
(Fig. 2C).
In the case of 18, 19, 20 and 21, it might be possible to eliminate
the CD contribution originated from thiirane moiety to give the
a
negative Cotton effect around 235 nm, respectively26

Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
6635
O
O
structure, and assigning of Amber77 charge. The ligands used in
the docking approach were sketched and minimized by SYBYL-X
2.0. The protomol was generated automatically, and other param-
eters were set as default. We chose 8 and 9, which represented our
compounds with thiirane moiety (S) and thiirane moiety (R)
respectively, to be carried out docking studies. The computational
study is supportive of the stereochemistry of the thiirane ring has
no effects on biological activity that both 8 and 9 are able to bind to
the active sites of MMP2 (Fig. 3a) and MMP9 (Fig. 3b).
a
O
O
c
c
O
O
N
H
S
O
N
H
S
O
O
O
S
18
16
11
O
O
b
N
H
S
O
N
H
S
O
S
17
19
Scheme 3. Reagents and conditions: (a) Ti(O-i-Pr)4,
D
-DET, CHPO (80%), DCM, rt–
0 °C, 75.2%; (b) Ti(O-i-Pr)4,
L-DET, CHPO, DCM, rt–0 °C, 76.8%; (c) thiourea, THF,
MeOH, rt.
4. Conclusion
All the target compounds with thiirane moiety were assayed for
their activities against MMP2, MMP9, APN and HDACs. The results
indicated that all the compounds exhibited highly selective inhibi-
tion against MMP2 and MMP9 compared with APN and HDACs. The
optically active (R)- and (S)-enantiomers of compounds 10 and 15
were equally active in inhibition of human gelatinases. The results
show that the configuration of thiirane moiety has little effect on
inhibitory activity. It should be mentioned that the sulfoxide ana-
logs of 15 were almost not active against gelatinases regardless of
their stereochemistry. The reason may be the electron withdraw-
ing ability of the sulfoxide is weaker than that of sulfone, which
resulted in more difficult Glu404-dependent deprotonation at the
methylene adjacent to the sulfoxide.
phenyl methyl sulfoxide moiety contributions, by subtracting one
CD spectrum from that of the other stereoisomer with the same
configuration at thiirane moiety. As both 18 and 19 had S-configu-
ration from thiirane moiety, subtracting the CD spectrum of 19
from that of 18 could calculatorily eliminated the effect of S-thi-
irane moiety, the resulting differential curve indicated the CD con-
tribution of S-sulfoxide. In the same way, if one subtracts the
spectrum of 18 from that of 19, the resulting curve would indicate
the R-sulfoxide contribution. Following the same method, by sub-
tracting the CD spectrum of 21 from that of 20, the CD contribution
of R-configuration from thiirane moiety should also be eliminated
to obtain the same mirror imaged arithmetically ‘isolated’ CD
curves for S and R sulfoxide. The arithmetically ‘isolated’ CD contri-
bution of S-sulfoxide provided a positive Cotton effect nearby
222 nm and a negative Cotton effect nearby 258 nm. Accordingly,
the ‘isolated’ CD curve of R-sulfoxide displayed a negative Cotton
effect nearby 222 nm and a positive Cotton effect nearby 258 nm,
respectively (Fig. 2D and E). The ‘isolated’ CD curves thus obtained
showed good agreement with the reported CD spectra of phenyl
methyl sulfoxide.26
5. Experimental section
5.1. Chemistry
Unless otherwise noted, materials were obtained from commer-
cial suppliers and used without further purification. The solvents of
dichloromethane, methanol and tetrahydrofuran had been distilled
before use. All reactions were monitored by TLC with 0.25 mm sil-
ica gel plates (60GF-254). UV light was used to visualize the spots.
Silica gel (300–400 mesh HaiYang) was used for column chromato-
graphic purification with Combiflash Rf 200 (Teledyne Isco) instru-
ments. Melting points were determined uncorrected on an
electrothermal melting point apparatus. The IR spectra were
recorded by means of KBr plate on a Nicolet 6700 FT-IR Spectrom-
eter. 1H NMR was recorded on Bruker DRX spectrometers at
400 MHz. Chemical shifts are given in parts per million (ppm) with
tetramethylsilane as an internal standard. Abbreviations are used
as follows: s = singlet, d = doublet, t = triplet, q = quartet, m = mul-
tiplet, dd = doublets of doublet, br = broad. Coupling constants (J
values) are given in hertz (Hz). High-resolution mass spectra were
determined on an Agilent Q-TOF-6250 spectrometer in Shandong
Analysis and Test Center in Ji’nan, China. ESI-MS spectra were
recorded on an API 4000 spectrometer. Analytical chiral HPLC per-
formed on a Shimadzu 20A HPLC instrument using a CHIRALPAK IA
Following the above discussion, the absolute configuration of
stereoisomer 18 should be assigned as (S,S); stereoisomer 19 was
consequently assigned as (R,S). Stereoisomers 20 and 21 were
deduced as (S,R), and (R,R), respectively.
The inhibitory potency of our compounds against MMP2 and
MMP9 was evaluated. For those compounds showing >50% inhibi-
tion activity at 10
lM, the IC50 values were determined. The activ-
ity toward the human gelatinases in Table
1
showed that
enantiomers 8 (S) and 9 (R), and their racemate 10 exhibited com-
parative activities. The similar trend was also observed in enan-
tiomers 13 (S) and 14 (R) and their racemate 15. These results
revealed the chirality configuration of the thiirane moiety had little
impact on inhibitory activity. Unfortunately, the sulfoxide analogs
were almost not active, regardless of the absolute configuration of
sulfoxide. We presumed that the weaker electron withdrawing
ability of sulfoxide relative to sulfone, which resulted in more dif-
ficult Glu404-dependent deprotonation at the methylene adjacent
to the sulfoxide, might be the reason why sulfoxide analogs were
not active.
column. Optical rotations were determined on
polarimeter.
a MCP 200
Similar to MMP2 and MMP9, APN and HDACs are both zinc-
dependant metalloproteinases. Thus the assay was performed on
APN and HDACs so as to identify the compounds’ selectivity.27
Bestatin and SAHA were used as the positive controls for APN
5.1.1. (S)-Oxiran-2-ylmethyl 4-methylbenzenesulfonate (2)
Paratoluenesulfonyl chloride (PTSC, 25.0 g) and (R)-oxiran-2-yl-
methanol (6.0 mL) were dissolved in anhydrous dichloromethane
(DCM, 250 mL), then, triethylamine (TEA, 36.0 mL) was dropwise
added in the mixture at 0 °C. After reacting for 3 h at 0 °C, the reac-
tion liquid was concentrated. At last, the residue was purified by
flash column chromatography with ethyl acetate/petroleum ether
to obtain the title compound 2 (17.6 g). White solid; yield:
and HDACs, respectively. Our compounds tested at 10 lM showed
no inhibition for APN and HDACs (Table 1), which confirmed the
unique Zn2+ chelation mechanism of thiirane moiety against gelati-
nases (Fig. 1A).
The docking processes were performed using Surflex-dock in
the SYBYL-X 2.0 software. The crystal structure of MMP2 (PDB
entry: 1QIB) and MMP9 (PDB entry: 1L6J) were refined by remov-
ing water molecules and the crystallized metals ions in the protein
85.0%; mp: 44–46 °C; [a]
25 = +18.3 (c 1.7, acetonitrile). IR (KBr)
D
1598, 1363, 1177, 969, 666, 556. 1H NMR (400 MHz, DMSO-d6) d
7.83 (d, J = 8.1 Hz, 2H), 7.52–7.46 (m, 2H), 4.43 (d, J = 11.6 Hz,

6636
Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
B
product 20
product 21
A
product 18
product 19
30
20
10
0
20
10
0
-10
-20
-30
-10
-20
200
220
240
260
280
300
320
340
360
200
220
240
260
280
300
320
340
360
Wavelength (nm)
Wavelength (nm)
C
D
18-19 (S)
19-18 (R)
40
30
20
10
0
-10
-20
-30
-40
200
220
240
260
280
300
320
340
360
Wavelength (nm)
20-21 (S)
21-20 (R)
E
40
30
20
10
0
-10
-20
-30
-40
200
220
240
260
280
300
320
340
360
Wavelength (nm)
Figure 2. (A) shows Cotton effects in CD spectra of products 18 and 19 in acetonitrile. The Cotton effects of products 18 and 19 with the same concentration (200
measured by Chirascan CD Spectrometer at 25 °C. (B) Shows Cotton effects in CD spectra of products 20 and 21 in acetonitrile. The Cotton effects of products 20 and 21 with
the same concentration (200 g/mL) were measured by Chirascan CD Spectrometer at 25 °C. (C) Shows Cotton effects in CD spectra of phenyl methyl sulfoxide. (D) Shows
Cotton effects in CD spectra of (18–19) and (19–18). (E) Shows Cotton effects in CD spectra of (20–21) and (21–20).
lg/mL) were
l

Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
6637
Figure 3. (a) Molecule 8 and 9 in the active site of MMP2, the carbon atoms of molecule 8 was colored green and the gray ball is zinc ion; (b) molecule 8 and 9 in the active
site of MMP9, the carbon atoms of molecule 8 was colored green.
1H), 3.85 (dddd, J = 7.0, 5.7, 3.7, 1.9 Hz, 1H), 3.26–3.17 (m, 1H), 2.78
(t, J = 4.6 Hz, 1H), 2.66–2.58 (m, 1H), 2.42 (s, 3H). ESI-MS m/z: 251.2
[M+Na]+.
The filtrate was added absolute methanol (MeOH, 60 mL) and
dropwise added TEA (37 mL). After 5 min, di-tert-butyl dicarbonate
((Boc)2O, 12.8 g) was added. Then, the ice bath was removed. 24 h
later, the reaction liquid was concentrated. And the residue was
purified by flash column chromatography with ethyl acetate/petro-
leum ether to give the title compound 5 (3.7 g). Light yellow solid;
5.1.2. (R)-2-Hydroxy-3-((4-hydroxyphenyl)thio)propyl 4-
methylbenzenesulfonate (3)
(S)-Oxiran-2-ylmethyl 4-methylbenzenesulfonate (2) (9.0 g)
and 4-mercaptophenol (5.0 g) were dissolved in anhydrous
dichloromethane (150 mL). After TEA (11.1 mL) was dropwise
added in the mixture at 0 °C, the ice bath was removed. The mix-
ture was reacted at room temperature for 4–5 h. Then, it was con-
centrated and evaporated, with the residue being purified by flash
column chromatography with ethyl acetate/petroleum ether to
give desired compound 3 (5.9 g). White solid; yield: 81.5%; mp:
yield: 81.1%; mp: 82–84 °C; [
a]
25 = À0.39 (c 1.0, acetonitrile). IR
D
(KBr) 3345, 3298, 2978, 2918, 1718, 1488, 1229, 1155, 1053, 852,
826, 771, 738. 1H NMR (400 MHz, DMSO-d6) d 9.37 (s, 1H), 7.50–
7.40 (m, 4H), 7.00–6.87 (m, 4H), 3.13–3.02 (m, 3H), 2.75–2.70
(m, 1H), 2.53–2.51 (m, 1H), 1.48 (s, 9H). ESI-MS m/z: 374.4 [M
+H]+. ESI-MS m/z: 372.3 [MÀH]À.
5.1.5. tert-Butyl (R)-(4-(4-((oxiran-2-ylmethyl)sulfonyl)
phenoxy)phenyl)carbamate (6)
96–98 °C; [a]
25 = +24.3 (c 0.6, acetonitrile). IR (KBr) 3372, 3146,
D
1597, 1582, 1495, 1365, 1257, 1190, 1177, 1097, 1074, 988, 905,
829, 815, 792, 665, 555. 1H NMR (400 MHz, DMSO-d6) d 9.58 (s,
1H), 7.76 (d, J = 8.3 Hz, 2H), 7.48 (d, J = 8.1 Hz, 2H), 7.15 (d,
J = 8.6 Hz, 2H), 6.71 (d, J = 8.6 Hz, 2H), 5.42 (d, J = 5.2 Hz, 1H),
4.06 (dd, J = 10.1, 3.3 Hz, 1H), 3.92 (dd, J = 10.1, 6.3 Hz, 1H), 3.69–
3.59 (m, 1H), 2.77 (d, J = 6.5 Hz, 2H), 2.43 (s, 3H). ESI-MS m/z:
377.4 [M+Na]+. ESI-MS m/z: 353.4 [MÀH]À.
At room temperature, tert-butyl (R)-(4-(4-((oxiran-2-ylmethyl)
thio)phenoxy)phenyl)carbamate (5) (3.5 g) and tetra isopropyl
titanate (Ti(O-i-Pr)4, 3.8 mL) were added in anhydrous dichloro-
methane (30 mL). Then, 80% cumene hydroperoxide (CHPO, 80%,
2.2 mL) was dropwise added to the mixture. One hour later, the
reaction liquid was concentrated. And the residue was purified
by flash column chromatography with ethyl acetate/petroleum
ether to give the title compound 6 (3.3 g). White solid; yield:
5.1.3. (R)-2-(((4-(4-Nitrophenoxy)phenyl)thio)methyl)oxirane
(4)
87.3%; mp: 118–120 °C; [
a
]
D
25 = À14.1 (c 0.6, acetonitrile). IR
(KBr) 3334, 2980, 1699, 1527, 1490, 1407, 1368, 1312, 1234,
1143, 850, 834, 767, 566. 1H NMR (400 MHz, DMSO-d6) d 9.47 (s,
1H), 7.89–7.83 (m, 2H), 7.55 (d, J = 8.9 Hz, 2H), 7.13–7.06 (m,
4H), 3.68 (dd, J = 14.6, 4.3 Hz, 1H), 3.50 (dd, J = 14.6, 7.1 Hz, 1H),
3.158–3.113 (m, 1H), 2.72 (dd, J = 5.2, 4.1 Hz, 1H), 2.44 (dd,
J = 5.3, 2.5 Hz, 1H), 1.48 (s, 9H). ESI-MS m/z: 428.4 [M+Na]+. ESI-
MS m/z: 404.6 [MÀH]À.
At room temperature, (R)-2-hydroxy-3-((4-hydroxyphenyl)
thio)propyl 4-methylbenzenesulfonate (3) (3.0 g) was added in
anhydrous dimethyl formamide (DMF, 50 mL), followed by adding
1-fluoro-4-nitrobenzene (3.0 g) and Cs2CO2 (8.1 g). After 12 h, the
reaction solutions was added some water, and then, extracted with
ethyl acetate. The organic layer was washed with brine
(30 mL Â 3), dried over anhydrous MgSO4, filtered and concen-
trated in vacuo. The residue was purified by flash column chro-
matography with ethyl acetate/petroleum ether to obtain the
5.1.6. tert-Butyl (S)-(4-(4-((thiiran-2-ylmethyl)sulfonyl)
phenoxy)phenyl)carbamate (7)
title compound
4
(4.15 g). Pale yellow oil; yield: 83.0%;
At room temperature, tert-butyl (R)-(4-(4-((oxiran-2-ylmethyl)-
sulfonyl)phenoxy)phenyl)carbamate (6) (2.0 g) and thiourea (2.0 g)
reacted in anhydrous dichloromethane (15 mL) and absolute
methanol (30 mL) overnight. The reaction liquid was concentrated.
And the residue was purified by flash column chromatography with
ethyl acetate/petroleum ether to give the title compound 7 (1.76 g).
[
a]
D
25 = À3.5 (c 0.5, acetonitrile). IR (KBr) 1582, 1487, 1343, 1243,
877, 846, 751. 1H NMR (400 MHz, DMSO-d6) d 8.29–8.23 (m, 2H),
7.57–7.51 (m, 2H), 7.19–7.12 (m, 4H), 3.24–3.11 (m, 3H), 2.78–
2.74 (m, 1H), 2.59 (dd, J = 5.1, 2.2 Hz, 1H). ESI-MS m/z: 304.4 [M
+H]+. ESI-MS m/z: 348.4 [M+HCOO]À.
White solid; yield: 84.5%; mp: 158–160 °C; [
a
]
D
25 = À0.7 (c 0.14, ace-
5.1.4. tert-Butyl (R)-(4-(4-((oxiran-2-ylmethyl)thio)phenoxy)
phenyl)carbamate (5)
At 0 °C, (R)-2-(((4-(4-nitrophenoxy)phenyl)thio)methyl)oxirane
(4) (3.7 g) was added in anhydrous tetrahydrofuran (THF, 60 mL),
followed by adding zinc powder (Zn, 32.0 g) and dropwise adding
acetic acid (AcOH, 13.9 mL). After 15 min, the mixture was filtered.
tonitrile). IR (KBr) 3325, 2979, 1698, 1530, 1310, 1239, 1140, 851,
834, 768, 565, 550, 515. 1H NMR (400 MHz, DMSO-d6) d 9.47 (s,
1H), 7.92–7.84 (m, 2H), 7.54 (d, J = 8.9 Hz, 2H), 7.14–7.06 (m, 4H),
3.62 (d, J = 6.7 Hz, 2H), 2.98 (dd, J = 6.4, 5.5 Hz, 1H), 3.013–2.951
(m, 1H), 2.19 (dd, J = 5.3, 1.2 Hz, 1H), 1.48 (s, 9H). ESI-MS m/z:
444.5 [M+Na]+. ESI-MS m/z: 420.3 [MÀH]À.

6638
Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
Compounds 9 and 10 were synthesized according to the same
procedure as compound 8.
washed with saturated brines (20 mL Â 3), dried with anhydrous
magnesium sulfate (MgSO4) concentrated and purified by flash col-
umn chromatography with ethyl acetate/petroleum ether to give
the title compound 11 (2.4 g). Light yellow solid; yield: 78.1%;
5.1.7. (S)-4-(4-((Thiiran-2-ylmethyl)sulfonyl)phenoxy)aniline
hydrochloride (8)
mp: 96–98 °C; [
a
]
25 = À4.8 (c 0.3, acetonitrile). IR (KBr) 3286,
D
tert-Butyl
(S)-(4-(4-((thiiran-2-ylmethyl)sulfonyl)phenoxy)
1659, 1552, 1525, 1507, 1490, 1277, 1256, 819, 516. 1H NMR
(400 MHz, DMSO-d6) d 9.95 (s, 1H), 7.59 (d, J = 8.9 Hz, 2H), 7.43
(d, J = 8.7 Hz, 2H), 6.99 (d, J = 8.9 Hz, 2H), 6.92 (d, J = 8.7 Hz, 2H),
3.14–3.05 (m, 3H), 2.76–2.70 (m, 1H), 2.53 (d, J = 2.2 Hz, 1H),
2.03 (s, 3H). ESI-MS m/z: 316.4 [M+H]+.
phenyl)carbamate (7) (1.7 g) was stirred in a solution of EtOAc
(20 mL) saturated by dry HCl gas. The reaction solution was stirred
at room temperature for overnight when the precipitation
appeared. The suspension was filtered with the filter being washed
with ether to give desired compound 8 (1.28 g). White powder;
yield: 89.0%; mp: 192–194 °C; 96.2% ee [column, CHIRALPAK IA
5.1.11. (R)-N-(4-(4-((Oxiran-2-ylmethyl)sulfonyl)phenoxy)
phenyl)acetamide (12)
(4.6 mm I.D. Â 250 mm
nol = 50:50 (v/v); flow rate, 0.8 mL/min; detection, UV 244 nm;
temperature, room temperature]; [
25 = +5.2 (c 0.7, methanol).
5 lm); mobile phase, n-hexane/etha-
At room temperature, (R)-N-(4-(4-((oxiran-2-ylmethyl)thio)
phenoxy)phenyl)acetamide (11) (0.5 g) and tetra isopropyl titanate
(Ti(O-i-Pr)4) (0.47 mL) were added in anhydrous dichloromethane
(15 mL). Then, 80% cumene hydroperoxide (CHPO, 80%, 1.0 mL)
was dropwise added to the mixture. One hour later, the reaction
liquid was concentrated. And the residue was purified by flash col-
umn chromatography with ethyl acetate/petroleum ether to give
the title compound 12 (0.5 g). Slight yellow oil; yield: 91.0%;
a
]
D
IR (KBr) 2850, 2595, 1586, 1501, 1488, 1314, 1254, 1142, 1085,
876, 860, 826, 780, 516. 1H NMR (400 MHz, DMSO-d6) d 10.23
(br, 3H), 7.95–7.90 (m, 2H), 7.48–7.43 (m, 2H), 7.30–7.24 (m,
2H), 7.23–7.18 (m, 2H), 3.72–3.59 (m, 2H), 3.05–2.95 (m, 1H),
2.56 (dd, J = 6.3, 1.1 Hz, 1H), 2.20 (dd, J = 5.3, 1.2 Hz, 1H). ESI-MS
m/z: 344.4 [M+Na]+. ESI-MS m/z: 320.3 [MÀH]À. HRMS m/z: calcd
for C15H15NO3S2 [M+H]+ 322.0493, found: 322.0566.
[
a
]
25 = À9.3 (c 0.4, acetonitrile). IR (KBr) 3301, 1665, 1531, 1506,
D
1488, 1314, 1296, 1245, 1137, 839, 788, 680, 595, 554, 526, 508.
1H NMR (400 MHz, DMSO-d6) d 10.04 (s, 1H), 7.92–7.84 (m, 2H),
7.70–7.65 (m, 2H), 7.19–7.07 (m, 4H), 3.72–3.40 (m, 3H), 3.159–
3.114 (m, 1H), 2.72 (dd, J = 5.2, 4.2 Hz, 1H), 2.44 (dd, J = 5.3,
2.5 Hz, 1H), 2.06 (s, 3H). ESI-MS m/z: 348.4 [M+H]+.
5.1.8. (R)-4-(4-((Thiiran-2-ylmethyl)sulfonyl)phenoxy)aniline
(9)
Synthesis of (R)-4-(4-((thiiran-2-ylmethyl)sulfonyl)phenoxy)
aniline (9) was performed according to the same procedure as
compound 8, with the sole substitution of (S)-oxiran-2-ylmethanol
(98.0% ee) as the reagent of choice. White powder; yield: 87.4%;
mp: 152–154 °C; 96.2% ee [column, CHIRALPAK IA (4.6 mm I.
Compounds 14 and 15 were synthesized according to the same
procedure as compound 13.
D. Â 250 mm
5
l
m); mobile phase, n-hexane/ethanol = 50:50
5.1.12. (S)-N-(4-(4-((Thiiran-2-ylmethyl)sulfonyl)phenoxy)
phenyl)acetamide (13)
(v/v); flow rate, 0.8 mL/min; detection, UV 244 nm; temperature,
room temperature]; [
a]
25 = À14.5 (c 1.0, methanol). IR (KBr)
At room temperature, (R)-N-(4-(4-((oxiran-2-ylmethyl)sul-
fonyl)phenoxy)phenyl)acetamide (12) (0.4 g) and thiourea (0.4 g)
reacted in anhydrous tetrahydrofuran (THF, 8.0 mL) and absolute
methanol (4.0 mL) overnight. The reaction liquid was concen-
trated. And the residue was purified by flash column chromatogra-
phy with ethyl acetate/petroleum ether to give the title compound
13 (0.39 g). White solid; yield: 92.5%; mp: 162–164 °C; 92.9% ee
D
2853, 2579, 1590, 1508, 1489, 1313, 1259, 1143, 1087, 877, 853,
831, 549, 519. 1H NMR (400 MHz, DMSO-d6) d 10.15 (br, 3H),
7.95–7.90 (m, 2H), 7.48–7.43 (m, 2H), 7.31–7.25 (m, 2H), 7.24–
7.18 (m, 2H), 3.72–3.58 (m, 2H), 3.04–2.95 (m, 1H), 2.56 (dd,
J = 6.3, 1.1 Hz, 1H), 2.20 (dd, J = 5.3, 1.2 Hz, 1H). ESI-MS m/z:
344.4 [M+Na]+. ESI-MS m/z: 320.3 [MÀH]À. HRMS m/z: calcd for
C
15H15NO3S2 [M+H]+ 322.0493, found: 322.0565.
[column, CHIRALPAK IA (4.6 mm I.D. Â 250 mm 5
lm); mobile
phase, n-hexane/ethanol/tetrahydrofuran = 65:35:5 (v/v/v); flow
5.1.9. 4-(4-((Thiiran-2-ylmethyl)sulfonyl)phenoxy)aniline (10,
ND-322)
rate, 1 mL/min; detection, UV 251 nm; temperature, room temper-
ature]; [a]
25 = +1.1 (c 0.4, acetonitrile). IR (KBr) 3298, 3258, 3197,
D
Synthesis of 4-(4-((thiiran-2-ylmethyl)sulfonyl)phenoxy)ani-
line (10, ND-322) was performed according to the same procedure
as compound 8, with the sole substitution of oxiran-2-ylmethanol
as the reagent of choice. White powder; yield: 86.7%; mp: 176–
178 °C. IR (KBr) 2850, 2591, 1586, 1502, 1313, 1255, 1142, 1086,
876, 860, 826, 780, 517. 1H NMR (400 MHz, DMSO-d6) d 10.28
(br, 3H), 7.96–7.90 (m, 2H), 7.51–7.44 (m, 2H), 7.32–7.26 (m,
2H), 7.24–7.19 (m, 2H), 3.71–3.59 (m, 2H), 3.04–2.94 (m, 1H),
2.56 (dd, J = 6.3, 1.1 Hz, 1H), 2.20 (dd, J = 5.3, 1.2 Hz, 1H). ESI-MS
m/z: 344.4 [M+Na]+. ESI-MS m/z: 320.3 [MÀH]À. HRMS m/z: calcd
for C15H15NO3S2 [M+H]+ 322.0493, found: 322.0580.
3138, 3093, 2927, 1663, 1615, 1584, 1557, 1505, 1489, 1244,
1225, 1145, 1087, 874, 858, 839, 755, 586, 542, 525, 511. 1H
NMR (400 MHz, DMSO-d6) d 10.05 (s, 1H), 7.88 (d, J = 8.9 Hz, 2H),
7.67 (d, J = 8.9 Hz, 2H), 7.17–7.09 (m, 4H), 3.63 (d, J = 6.7 Hz, 2H),
3.03–2.93 (m, 1H), 2.55 (d, J = 5.5 Hz, 1H), 2.19 (d, J = 5.2 Hz, 1H),
2.05 (s, 3H). HRMS m/z: calcd for C17H17NO4S2 [M+H]+ 364.0599,
found: 364.0674.
5.1.13. (R)-N-(4-(4-((Thiiran-2-ylmethyl)sulfonyl)phenoxy)
phenyl)acetamide (14)
Synthesis of (R)-N-(4-(4-((thiiran-2-ylmethyl)sulfonyl)phe-
noxy)phenyl)acetamide (14) was performed according to the same
procedure as compound 13, with the sole substitution of (S)-oxi-
ran-2-ylmethanol (98.0% ee) as the reagent of choice. White solid;
yield: 91.4%; mp: 162–164 °C; 93.6% ee [column, CHIRALPAK IA
5.1.10. (R)-N-(4-(4-((Oxiran-2-ylmethyl)thio)phenoxy)phenyl)
acetamide (11)
At 0 °C, (R)-2-(((4-(4-nitrophenoxy)phenyl)thio)methyl)oxirane
(4) (3.0 g) was added in anhydrous tetrahydrofuran (THF, 50 mL),
followed by adding zinc powder (Zn, 26.0 g) and dropwise adding
acetic acid (AcOH, 11.3 mL). After 15 min, the mixture was filtered.
The filtrate was added absolute methanol (MeOH, 50 mL) and
dropwise added TEA (30 mL). After 5 min, acetyl chloride
(7.0 mL) was added. Then, the ice bath was removed. 15 min later,
the reaction liquid was concentrated. And the residue was added
some water, extracted with ethyl acetate (EtOAc) (30 mL Â 3),
(4.6 mm I.D. Â 250 mm 5
lm); mobile phase, n-hexane/ethanol/
tetrahydrofuran = 65:35:5 (v/v/v); flow rate, 1 mL/min; detection,
UV 251 nm; temperature, room temperature]; [
a]
25 = À5.7 (c 0.5,
D
acetonitrile). IR (KBr) 3298, 3258, 3198, 3138, 3093, 2927, 1663,
1615, 1557, 1505, 1489, 1244, 1145, 874, 859, 839, 755, 586,
542, 525, 511. 1H NMR (400 MHz, DMSO-d6) d 10.05 (s, 1H), 7.88
(d, J = 8.9 Hz, 2H), 7.67 (d, J = 8.9 Hz, 2H), 7.17–7.08 (m, 4H), 3.63
(d, J = 6.7 Hz, 2H), 3.03–2.94 (m, 1H), 2.55 (d, J = 5.5 Hz, 1H), 2.19

Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
6639
(d, J = 5.3 Hz, 1H), 2.06 (s, 3H). HRMS m/z: calcd for C17H17NO4S2
(4.6 mm I.D. Â 250 mm 5
l
m); mobile phase, n-hexane/ethanol/
[M+H]+ 364.0599, found: 364.0683.
tetrahydrofuran = 74:25:1 (v/v/v); flow rate, 1 mL/min; detection,
UV 255 nm; temperature, room temperature]; [
a
]
D
25 = +24.4 (c 0.5,
5.1.14. N-(4-(4-((Thiiran-2-ylmethyl)sulfonyl)phenoxy)phenyl)
acetamide (15, ND-364)
acetonitrile). IR (KBr) 3297, 1678, 1659, 1548, 1507, 1488, 1255,
1022, 833, 523. 1H NMR (400 MHz, DMSO-d6) d 10.01 (s, 1H),
7.76–7.56 (m, 4H), 7.14–7.06 (m, 4H), 3.32–3.12 (m, 2H), 3.12–
2.80 (m, 1H), 2.61 (d, J = 6.1 Hz, 1H), 2.35 (dd, J = 54.6, 5.2 Hz,
1H), 2.05 (s, 3H). HRMS m/z: calcd for C17H17NO3S2 [M+H]+
348.0650, found: 348.0720.
Synthesis of N-(4-(4-((thiiran-2-ylmethyl)sulfonyl)phenoxy)
phenyl)acetamide (15, ND-364) was performed according to the
same procedure as compound 13, with the sole substitution of oxi-
ran-2-ylmethanol as the reagent of choice. White solid; yield:
89.6%; mp: 162–164 °C. IR (KBr) 3298, 3259, 3198, 3093, 2928,
1663, 1615, 1557, 1505, 1489, 1244, 1226, 1145, 874, 858, 839,
755, 586, 542, 525, 511. 1H NMR (400 MHz, DMSO-d6) d 10.05 (s,
1H), 7.88 (d, J = 8.8 Hz, 2H), 7.67 (d, J = 8.9 Hz, 2H), 7.17–7.08 (m,
4H), 3.63 (d, J = 6.7 Hz, 2H), 3.03–2.94 (m, 1H), 2.58–2.53 (m,
1H), 2.19 (d, J = 5.3 Hz, 1H), 2.05 (s, 3H). HRMS m/z: calcd for
5.1.18. N-(4-(4-((S)-(((R)-Thiiran-2-yl)methyl)sulfinyl)phenoxy)
phenyl)acetamide (20)
Synthesis of N-(4-(4-((S)-(((R)-thiiran-2-yl)methyl)sulfinyl)
phenoxy)phenyl)acetamide (20) was performed according to the
same procedure as compound 18, with the sole substitution of
(S)-oxiran-2-ylmethanol (98.0% ee) as the reagent of choice. White
solid; yield: 88.9%; mp: 150–152 °C; 1:67:32 dr [column, CHIRAL-
C
17H17NO4S2 [M+H]+ 364.0599, found: 364.0662.
5.1.15. N-(4-(4-((S)-(((R)-Oxiran-2-yl)methyl)sulfinyl)phenoxy)
phenyl)acetamide (16)
(R)-N-(4-(4-((Oxiran-2-ylmethyl)thio)phenoxy)phenyl)ac-
etamide (11) (1.0 g), tetra isopropyl titanate (Ti(O-i-Pr)4, 0.94 mL)
PAK IA (4.6 mm I.D. Â 250 mm 5
lm); mobile phase, n-hexane/
ethanol/tetrahydrofuran = 74:25:1 (v/v/v); flow rate, 1 mL/min;
detection, UV 255 nm; temperature, room temperature];
[
a
]
25 = À47.2 (c 0.4, acetonitrile). IR (KBr) 3296, 1662, 1617,
D
and (À)-diethyl
D-tartrate (D-DET, 2.2 mL) were added in anhy-
1557, 1505, 1488, 1242, 1222, 1035, 836, 520. 1H NMR
(400 MHz, DMSO-d6) d 10.01 (s, 1H), 7.72–7.61 (m, 4H), 7.14–
7.05 (m, 4H), 3.31–3.12 (m, 2H), 3.12–2.82 (m, 1H), 2.61 (d,
J = 6.0 Hz, 1H), 2.35 (dd, J = 54.7, 5.2 Hz, 1H), 2.05 (s, 3H). HRMS
m/z: calcd for C17H17NO3S2 [M+H]+ 348.0650, found: 348.0720.
drous dichloromethane (25 mL). After 5 min, 80% cumene
hydroperoxide (CHPO 80%, 0.64 mL) was dropwise added to the
mixture at 0 °C, then, reacted for 24 h at the same temperature.
The mixture was purified by flash column chromatography with
ethyl acetate. The liquid was concentrated. And the residue was
purified by flash column chromatography with ethyl acetate/petro-
leum ether to give the title compound 16 (0.79 g). Faint yellow
5.1.19. N-(4-(4-((R)-(((R)-Thiiran-2-yl)methyl)sulfinyl)phenoxy)
phenyl)acetamide (21)
solid; yield: 75.2%; mp: 86–88 °C; [
a
]
25 = À43.8 (c 0.6, acetonitrile).
D
IR (KBr) 3262, 3198, 3132, 3066, 2965, 2920, 1686, 1545, 1507,
1489, 1256, 1021, 852, 834, 523. 1H NMR (400 MHz, DMSO-d6) d
10.01 (s, 1H), 7.71–7.60 (m, 4H), 7.11 (d, J = 8.7 Hz, 2H), 7.06 (d,
J = 8.9 Hz, 2H), 3.26–3.17 (m, 1H), 3.14–2.99 (m, 2H), 2.84–2.73
(m, 1H), 2.61 (ddd, J = 20.0, 5.2, 2.4 Hz, 1H), 2.05 (s, 3H). ESI-MS
m/z: 332.5 [M+H]+.
N-(4-(4-((R)-(((R)-Thiiran-2-yl)methyl)sulfinyl)phenoxy)phe-
nyl)acetamide (21) was performed according to the same
procedure as compound 19, with the sole substitution of
(S)-oxiran-2-ylmethanol (98.0% ee) as the reagent of choice. White
solid; yield: 86.4%; mp: 136–138 °C; 2:27:71 dr [column,
CHIRALPAK IA (4.6 mm I.D. Â 250 mm
5 lm); mobile phase,
n-hexane/ethanol/tetrahydrofuran = 74:25:1 (v/v/v); flow rate,
Compounds 19, 20 and 21 were synthesized according to the
same procedure as compound 18.
1 mL/min; detection, UV 255 nm; temperature, room tempera-
ture]; [a]
25 = +20.1 (c 0.4, acetonitrile). IR (KBr) 3297, 1656, 1552,
D
1507, 1258, 1021, 834, 524. 1H NMR (400 MHz, DMSO-d6)
d 10.01 (s, 1H), 7.75–7.57 (m, 4H), 7.17–7.03 (m, 4H), 3.32–3.12
(m, 2H), 3.12–2.81 (m, 1H), 2.61 (d, J = 6.3 Hz, 1H), 2.35
(dd, J = 54.7, 5.1 Hz, 1H), 2.05 (s, 3H). HRMS m/z: calcd for
5.1.16. N-(4-(4-((S)-(((S)-Thiiran-2-yl)methyl)sulfinyl)phenoxy)
phenyl)acetamide (18)
N-(4-(4-((S)-(((R)-Oxiran-2-yl)methyl)sulfinyl)phenoxy)phe-
nyl)acetamide (16) (0.52 g) and thiourea (0.52 g) reacted in anhy-
drous tetrahydrofuran (THF, 10.4 mL) and absolute methanol
(5.2 mL) overnight. The reaction liquid was concentrated. And the
residue was purified by flash column chromatography with ethyl
acetate/petroleum ether to give the title compound 18 (0.49 g).
White solid; yield: 89.4%; mp: 134–136 °C; 23:76:1 dr [column,
C
17H17NO3S2 [M+H]+ 348.0650, found: 348.0737.
5.2. In vitro MMP2 and MMP9 inhibition assay
Active human MMP2 full length protein and active human
MMP9 full length protein were purchased from Abcam, The fluoro-
genic substrate Mca-Pro-Leu-Gly-Leu-Dap(Dnp)-Ala-Arg-NH2 was
purchased from AnaSpec. The inhibition potency of our compounds
against MMP2 and MMP9 was evaluated though a fluorometric
assay using 384-well plates with a plate reader (Varioskan,
Thermo), at excitation and emission wavelengths of 328 and
393 nm. Substrate hydrolysis were monitored for 15 min in a
buffer (50 mM HEPES, pH 7.5, 150 mM NaCl, 5 mM CaCl2, 0.01%
CHIRALPAK IA (4.6 mm I.D. Â 250 mm 5
lm); mobile phase, n-hex-
ane/ethanol/tetrahydrofuran = 74:25:1 (v/v/v); flow rate, 1 mL/min;
detection, UV 255 nm; temperature, room temperature];
[
a
]
25 = À36.3 (c 0.3, acetonitrile). IR (KBr) 3297, 1658, 1506,
D
1488, 1245, 1021, 834, 524. 1H NMR (400 MHz, DMSO-d6) d
10.01 (s, 1H), 7.74–7.61 (m, 4H), 7.17–7.04 (m, 4H), 3.31–2.81
(m, 3H), 2.61 (d, J = 6.3 Hz, 1H), 2.35 (dd, J = 54.8, 5.2 Hz, 1H),
2.05 (s, 3H). HRMS m/z: calcd for C17H17NO3S2 [M+H]+ 348.0650,
found: 348.0719.
Brij-35 and 1% DMSO) contained 10
pounds showing >50% inhibition activity at 10
values were obtained by dose response measurements using inhi-
bitor range of concentration (1 nM–10 m) and enzyme concentra-
tion equal to 3 nM. The enzyme was preincubated with the
inhibitor 2 h before assessment of activity. NNGH was a control
l
M substrate. For those com-
l
m concn, the IC50
5.1.17. N-(4-(4-((R)-(((S)-Thiiran-2-yl)methyl)sulfinyl)phenoxy)
phenyl)acetamide (19)
Synthesis of N-(4-(4-((R)-(((S)-thiiran-2-yl)methyl)sulfinyl)
phenoxy)phenyl)acetamide (19) was performed according to the
same procedure as compound 18, with the sole substitution of
l
diethyl-
L
-tartrate (
L
-DET) as the ligand of choice. White solid;
drug. Data analysis was performed using Prism
(GraphPad).
5 software
yield: 87.2%; mp: 114–116 °C; 60:38:2 dr [column, CHIRALPAK IA

6640
Y. Yan et al. / Bioorg. Med. Chem. 23 (2015) 6632–6640
5.3. In vitro APN inhibition assay
References and notes
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l
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This work was supported by National High-Tech R&D Program
of China (863 Program) (Grant No. 2014AA020523), National Nat-
ural Science Foundation of China (Grant Nos. 21302111, 81373282,
21172134), China Postdoctoral Science Foundation funded project
(Grant Nos. 2013M540558 and 2014T70654), Promotive research
foundation for excellent young and middle-aged scientists of Shan-
dong Province (Grant No. BS2015YY016).