Facile diverted synthesis of pyrrolidinyl triazoles using organotrifluoroborate: Discovery of potential mPTP blockers

Article abstract of DOI:10.1039/c4ob01967a

This article describes the rapid and diversified synthesis of pyrrolidinyl triazoles for the discovery of mitochondrial permeability transition pore (mPTP) blockers. The 1,3-dipolar cycloaddition of ethynyl trifluoroborate with azidopyrrolidine produced a

Full text of DOI:10.1039/c4ob01967a

Organic &
Biomolecular Chemistry
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Facile diverted synthesis of pyrrolidinyl triazoles
using organotrifluoroborate: discovery of potential
mPTP blockers†
Cite this: Org. Biomol. Chem., 2014,
2, 9674
1
a,b
b
a,c
a
a,c
Sun hwa Jung, Kihang Choi, Ae Nim Pae, Jae Kyun Lee, Hyunah Choo,
a,c
a,c
a,c
Gyochang Keum,* Yong Seo Cho and Sun-Joon Min*
This article describes the rapid and diversified synthesis of pyrrolidinyl triazoles for the discovery of mito-
chondrial permeability transition pore (mPTP) blockers. The 1,3-dipolar cycloaddition of ethynyl trifluoro-
borate with azidopyrrolidine produced a key intermediate, triazolyl trifluoroborate 4, which subsequently
underwent a Suzuki–Miyaura coupling reaction to afford a series of 1,4-disubstituted triazoles 2. Sub-
sequent biological evaluation of these derivatives indicated 2ag and 2aj as the most potent mPTP blockers
exhibiting excellent cytochrome P450 (CYP) stability when compared to the previously reported oxime
analogue 1. The present work clearly demonstrates that a 1,2,3-triazole can be used as a stable oxime
surrogate. Furthermore, it suggests that late-stage diversification through coupling reactions of organo-
trifluoroborates is suitable for the rapid discovery of biologically active molecules.
Received 16th September 2014,
Accepted 7th October 2014
DOI: 10.1039/c4ob01967a
www.rsc.org/obc
Recently, we have identified pyrrolidinyl oxime, 1, as an
mPTP (mitochondrial permeability transition pore) blocker,
1
. Introduction
1
,2,3-Triazoles are an important class of heterocycles in which is a viable therapeutic target for the treatment of
1
9
pharmaceutical science, chemical biology, supramolecular Alzheimer’s disease (AD). It effectively recovered amyloid
1
–5
chemistry and materials science. In particular, various med- beta-induced mitochondrial dysfunction; however, the cyto-
icinal agents contain triazoles as important pharmacophores, chrome P450 (CYP) enzyme inhibition study revealed that it
which can be favorable in the binding to biomolecular significantly reduced CYP enzymatic activities, which can
6
targets. Triazoles are often used as peptide bond isosteres cause side effects such as a drug–drug interaction. In this
because of their planarity and enhanced physiochemical pro- regard, we proposed that the stable 1,2,3-triazole could serve
7
–9
perties such as increased metabolic stability and solubility.
as an effective isostere of oxime to improve the CYP stability
2
0
The nitrogen atoms in the triazole rings have hydrogen without reducing the mPTP inhibitory activity. In addition,
bonding capabilities and are not protonated at physiological incorporation of substituents on the aromatic ring can alter
pH because of their low basicity.
the effect of CYP inhibition. Considering these structural
The Huisgen 1,3-dipolar cycloaddition of azides and modifications, we propose triazole derivatives 2 as new
9
–13
alkynes is widely used for the synthesis of 1,2,3-triazoles.
The copper(I) catalyzed version of this reaction, using azides
candidates for mPTP blockers (Fig. 1).
As described in Scheme 1, we designed an efficient, step-
and terminal alkynes, provides 1,4-disubstituted 1,2,3-triazoles economical synthetic approach toward a chemical library of
1
4–18
with high regioselectivity,
making this reaction a powerful diverse 1,2,3-triazole derivatives. The synthesis of a triazole via
tool in medicinal chemistry for the structural modification of
lead compounds.
a
Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and
Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, South Korea
b
Department of Chemistry, Korea University, Seoul 136-701, South Korea
c
Department of Biological Chemistry, Korea University of Science and Technology
(
UST), 176 Gajung-dong, 217 Gajungro, Yuseong-gu, Daejeon, 305-333, South Korea.
E-mail: gkeum@kist.re.kr, sjmin@kist.re.kr
Electronic supplementary information (ESI) available. See DOI: 10.1039/
c4ob01967a
†
Fig. 1 Structures of pyrrolidinyl oxime 1 and triazole derivatives 2.
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Table 1 Optimization of the cycloaddition reaction conditions
Entry
1
Conditions
Temp. (°C)
Time (h)
Yield (%)
CuI
CuI
CuI
CuI, TEA
60
60
90
50
50
50
50
50
60
60
90
60
17
20
24
24
24
24
24
24
15
3
24
40
28
—
—
—
—
—
a
2
3
4
5
6
7
8
CuI, K
CuI, Cs
2
CO
CO
3
2
3
Scheme 1 Proposed synthesis of 1-pyrrolidinyl-1,2,3-triazoles 2.
CuI, iPr
CuI, iPr
CuBr, Cs
CuBr, Cs
CuBr, Cs
CuBr, Cs
NEt
NH
2
2
a
b
9
2
CO
2
CO
2
CO
2
CO
3
3
3
3
—
10
11
12
, DMEDA
, DMEDA
, DMEDA
40
85
Trace
a typical 1,3-cycloaddition requires the preparation of a term-
inal alkyne as a precursor; hence, this strategy is not effective
for achieving molecular diversity. Alternatively, we envisioned
that triazolyl trifluoroborate 4, derived from the annulation of
0.5
15
a
a
b
Reaction was performed in acetone-d
6
.
The deboronated product 10
was formed exclusively.
2
1,22
ethynyl trifluoroborate 6
and azide 7, can undergo a rapid
Suzuki–Miyaura coupling reaction to afford various triazole
2
3–25
analogues 3.
A recent report showed the transformation
of 6 to the corresponding triazolyl trifluoroborates, and sub-
sequent cross-coupling reactions, to afford 1,4-disubstituted
2
6
1
,2,3-triazoles.
However, this protocol was only applied
Table 2 Cycloaddition reaction of 6 with azides 11 under optimized
conditions
to a limited number of substrates, such as primary or aromatic
azides, and no further applications of the synthesized
compounds were pursued.
In this paper, we report an efficient and divergent synthesis
of various highly functionalized 1-pyrrolidinyl 4-aryl 1,2,3-tri-
azoles 2 via triazolyl trifluoroborates for the discovery of mPTP
blockers. Furthermore, we investigate the effect of structural
modification of oximes into triazoles on the target efficacy and
CYP enzyme stability.
1
Entry
R
Time (h)
Product
Yield (%)
1
2
3
HOCH
2
CH
2
CH
(11b)
PhCHvCHCH
2
(11a)
(11c)
0.5
1
0.5
12a
12b
12c
72
62
87
2 2
EtO CCH
2
4
1.5
12d
71
2
. Results and discussion
As depicted in Table 1, we performed a model study through
the cycloaddition of 6, using benzyl azide 8 as a substrate.
Based on the reaction conditions reported in the literature,
2
7
5
1.5
12e
45
we employed copper(I) halides as catalysts as well as various
bases and additives. Initially, the desired triazole trifluoro-
borate 9 was obtained in low yields when copper(I) iodide was
used (entries 1–3). We explored several bases in order to
improve the reaction yield, but the cycloaddition reactions did
not afford 9 in any of the cases (entries 4–8). However, 9 was
formed in high yield when the reaction with copper(I) bromide
and cesium carbonate in the presence of N,N-dimethylethyl-
enediamine (DMEDA) was performed at 90 °C for 30 min
6
7
24
12f
No reaction
90
0.5
12g
2
8,29
8
9
1
3
12h
12i
72
69
(entry 11).
The choice of solvent system is crucial to
prevent the generation of side product 10, which is most likely
3
0
formed by protodeboronation via a solvolysis mechanism.
After the optimal reaction conditions were selected, the
scope of the cycloaddition reaction of 6 with various substrates
was briefly investigated (Table 2). In general, the reactions of
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Table 3 Model study of the Suzuki–Miyaura cross-coupling reaction
triazole derivatives 2 as mPTP blockers (Scheme 2). Starting
from commercially available 3-hydroxy N-Boc-pyrrolidine 15,
3-azidopyrrolidine 7 was easily prepared by mesylation and
consecutive S 2 displacement of the azide. According to the
N
experimental procedure previously established in Table 1, we
attempted the 1,3-dipolar cycloaddition of potassium ethynyl
trifluoroborate 6 with azide 7. As anticipated, the desired tri-
azolyl trifluoroborate 4 was obtained in 70% yield. In the
meantime, 2-bromo-1-benzyloxybenzenes 17, containing either
a fluoride or chloride substituent at the 4-position, were easily
prepared as coupling partners by benzylation of bromophenols
Entry
Catalyst
Base
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
2
2
2
2
K
2
CO
Cs CO
PO
3
3
3
3
—
—
8
99
78
76
96
100
9
2
3
K
3
4
Na
2
Na
2
Na
2
Na
2
Na
2
Na
2
Na
2
Na
2
CO
CO
CO
CO
CO
CO
CO
CO
3
3
3
3
3
3
3
3
18
12
18
7
18
24
18
18
16. A coupling reaction of 4 and 17 could then be completed
PdCl
Pd(PPh
Pd(dba)
2 2 2
(dppf)·CH Cl
3
)
4
under the optimized conditions. This reaction proceeded suc-
cessfully, giving 1,4-disubstituted triazoles 3 in moderate
yields. Removal of the Boc protecting group on 3 using trifluoro-
acetic acid afforded the secondary amine 18 as a salt. This
was then subjected to reductive amination, acylation, and sul-
2
Pd
2
Pd
2
Pd
2
Pd
2
(dba)
3
3
3
3
a
9
(dba)
(dba)
(dba)
b
1
1
0
1
94
88
c
a
b
c
No ligand was used. XPhos was used as a ligand. Catalyst (2 mol%), fonylation to provide N-functionalized pyrrolidines 2 in good
ligand (4 mol%).
yields. Thus, we obtained a series of twenty new triazole
derivatives in this concise and divergent manner using 4 as a
key intermediate.
The inhibitory activity of pyrrolidinyl triazoles 2 against
aromatic or aliphatic azides 11 afforded the corresponding amyloid beta-induced mPTP opening was evaluated by a cell-
3
2,33
triazoles 12 in good to excellent yields. It was found that based JC-1 assay (Fig. 2).
In this assay, the color of the JC-1
various functional groups, such as alcohol, ester, allyl, and car- dye changed from green to red as the mitochondrial
bamate, were tolerated under these reaction conditions membrane potential increased. Thus, the lower the percent
(entries 1–3, and 5). In particular, secondary pyrrolidine/ increase of the green/red (g/r) ratio of the compound, the
piperizine azides 11d and 11e gave the desired products 12d higher is the recovery of mitochondrial function in the
and 12e in good yields (entries 4, 5), which could then be cell. Twelve of the triazole derivatives 2 increased the inhi-
applied to the divergent synthesis of the proposed 1,4-disubsti- bition of mPTP opening with less than 40% increase in the g/r
tuted triazole library. While the sterically demanding 2,6- ratio, indicating that the triazole is an effective structural
dimethylphenyl azide 11i was readily converted to triazole 12i surrogate of oxime. Further consideration of the structure–
within 3 h (entry 9), the use of adamantyl azide 11f did activity relationship (SAR) demonstrated the 2a series contain-
not provide the desired product 12f because of the high steric ing fluorine on the internal phenyl ring (X = F) to be more
hindrance (entry 6).
active than the chlorine-substituted 2b compounds. Smaller
position were found to increase
The Suzuki–Miyaura coupling reaction was then explored in substituents at the
R
order to produce a variety of derivatives in the late-stage the inhibitory activity against mPTP opening. In particular,
functionalization, as suggested in Scheme 1. The reaction of 9 electron-withdrawing groups, such as carbonyl or sulfonyl,
with 4-bromobenzonitrile 13 was tested, and the results are between pyrrolidine and the terminal phenyl ring significantly
3
1
summarized in Table 3. Following a literature procedure, the enhanced the inhibitory activity when compared to the initial
initial reactions were attempted in the presence of Pd(OAc)2 lead compound 1.
and SPhos using various bases. When K
2
CO
3
, Cs
2
CO
3
, and
In order to determine the effect of triazoles on the CYP
K PO were used as bases, 14 was not formed at all, or was stability, the inhibitory activities of selected compounds 2
3
4
obtained in very low yield. However, the use of Na CO as a against five CYP450 isozymes in the human liver were
2
3
base dramatically increased the yield to up to 99%. A variety of tested. Using the CYP450 screening kits, the percent
catalysts were also screened in order to optimize the reaction remaining activity of the CYP enzymes after treatment with
conditions. Among the catalysts tested, Pd (dba) provided the 2 was obtained, as shown in Table 4. The selected com-
2
3
best results, affording triazole 14 in quantitative yield. Many pounds 2 significantly increased the percent CYP remaining
solvent systems were used, such as DMF/H O, DME, THF, and activities in comparison with oxime 1. In particular, the
2
dioxane; however, all these afforded lower yields of the most active triazole derivatives 2ag and 2aj, containing
coupled product 14. Alternatively, ethanol gave higher yields, 4-fluorobenzoyl and 4-fluorobenzenesulfonyl groups, exhibited
suggesting that it is a critical component in the reaction relatively low inhibitory activities against the tested CYP
efficiency.
isozymes. This suggested that this triazole-based structural
Given the positive results from the optimized cycloaddition modification played an important role in the stability
reaction and the Suzuki–Miyaura coupling reaction in the of the CYP enzymes as well as in blocking the mPTP
model study, these reactions were applied to the synthesis of opening.
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Scheme 2 Divergent synthesis of 1-pyrrolidynyl triazoles 2: (a) (i) MsCl, TEA, CH
2
Cl
2
, rt, 18 h, (ii) NaN
3
, DMF, 80 °C, 3 h, 85%; (b) 6, CuBr, Cs
(dba) , SPhos,
, AcOH, THF, rt, 24 h (for
3
N, THF, rt, 24 h (for 2ai–j and 2bi–j).
2 3
CO ,
DMEDA, DMSO, 90 °C, 1.5 h, 70%; (c) 3,4-dichlorobenzyl chloride, K
Na CO , 85 °C, 18 h, 54% (3a), and 53% (3b); (e) TFA, CH Cl , rt, 0.5 h, 99% (18a), and 99% (18b); (f) ArCHO, NaBH(OAc)
aa–e and 2ba–e), or ArCOCl, Et N, THF, rt, 24 h (for 2af–h and 2bf–h), or ArSO Cl, Et
2
CO
3
, KI, acetone, 60 °C, 75% (17a), and 95% (17b); (d) Pd
2
3
2
3
2
2
3
2
3
2
Fig. 2 Inhibitory activity of 2 against amyloid beta-induced mPTP opening. Percent increase in the fluorescence ratio (green/red) after treatment of
each compound with amyloid beta with respect to that of amyloid beta alone (100%). Cyclosporin A (CsA) was used as a control.
their inhibitory activity against amyloid beta-induced mPTP
opening. The reaction conditions that were optimized in the
3
. Conclusion
In this study, we have demonstrated the synthesis of twenty model system were successfully applied to the synthesis of key
pyrrolidinyl triazoles 2 via cycloaddition of ethynyl trifluoro- intermediates 4, which were transformed to a library of N-func-
borate 6, followed by the Suzuki–Miyaura coupling reaction of tionalized pyrrolidinyl triazoles 2 in a divergent manner with
the corresponding cycloadducts. These were then evaluated for high overall yields. Thus, we believe that this methodology is
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a,b
Table 4 CYP inhibition of the selected compounds 2
3 2
chemical shifts were referenced to external BF ·OEt (0.0 ppm)
with a negative sign indicating an upfield shift.
Potassium ethynyltrifluoroborate (6). To a solution of
c
%
CYP isozyme remaining activity
22
Compds
1A2
2D6
2C9
3A4
2C19 ethynylmagnesium bromide in THF (20 mL, 10.0 mmol, 0.5 M
in THF solution) was added trimethylborate (1.59 g,
2
2
2
2
2
2
1
ab
ag
aj
bb
bg
bj
67.97
83.44
86.97
62.32
65.10
68.08
3.24
47.00
32.74
20.66
33.77
80.28
23.30
41.60
34.67
10.44
12.34
36.74
38.72
8.32
26.72
16.83
−0.06
9.85
11.21
20.47
13.64
15.3 mmol) at −78 °C. The solution was stirred for 1 h at this
102.41
137.73
44.25
78.86
37.66
6.25
temperature, and then warmed up to −20 °C and stirred for
14.06 1 h. To the resulting white suspension, a solution of KHF2
20.67
5.37
—
(
4.71 g, 60.3 mmol) in distilled water (15 mL) was added at
−
20 °C and the solution was stirred at this temperature for 1 h
5.77 and at room temperature for additional 1 h. The obtained reac-
d
Control
4.27
6.66
a
b
tion mixture was concentrated and the residue was dissolved
value represents the mean of duplicated experiments. The remaining in hot acetone. The residue was removed by filtration and the
Each value represents the mean of triplicate experiments. Each
c
activity of each isozyme was obtained at a concentration of 10 μM
using a fluorogenic Vivid® CYP450 screening kit. The reference
compounds for each CYP isozyme assay are as follows:
filtrate was concentrated to give the title compound 6 (1.05 g,
d
1
8
0%) as a white solid; mp 208.0–211.3 °C (decomp.); H NMR
1
3
6 6
α-naphthoflavone (1A2), quinidine (2D6), sulfaphenazole (2C9), (DMSO-d , 300 MHz) δ 1.90 (s, 1H). C NMR (DMSO-d ,
1
9
ketoconazole (3A4), and miconazole (2C19).
7
−
−
5 MHz) δ 98.5, 78.9. F NMR (DMSO-d , 376 MHz) δ −132.2,
6
1
1
132.3, −132.4, 132.5. B NMR (DMSO-d
2.16, −2.44, −2.72.
6
, 128 MHz) δ −1.87,
Potassium (1-benzyl-1H-1,2,3-triazol-4-yl)trifluoroborate (9)
(
Table 1). To a solution of potassium ethynyltrifluoroborate 6
useful for the rapid preparation of a large number of 1,4-di-
substituted 1,2,3-triazole analogs.
(
21.0 mg, 159 μmol), CuBr (2.30 mg, 15.9 μmol), N,N-dimethyl-
ethylenediamine (3.40 μL, 31.8 μmol) and Cs CO (51.0 mg,
Screening of the triazole analogues 2 in the JC-1 assay
identified 2ag and 2aj as potent mPTP blockers. These also
showed excellent CYP stability in comparison with oxime 1.
These findings indicate that the 1,2,3-triazole functional group
can be used as a stable isostere of oxime to improve the CYP
stability while maintaining the inhibitory activity against a
molecular target.
2
3
6
159 μmol) in DMSO-d (0.7 mL) in a NMR tube was added
benzyl azide 8 (21.2 mg, 159 μmol) at room temperature.
The reaction mixture was carried out at 90 °C for 30 min
1
(
until the H NMR indicated completion of the reaction).
Then, the solvent was completely removed under high
vacuum. The residual product was dissolved in dry acetone
(
3 × 5 mL) and the insoluble salts were removed by
filtration through Celite® and activated carbon. The solvent
was concentrated and the crude solid was purified by dissol-
ution in a minimal amount of dry acetone and precipitation
Experimental section
General
2
with Et O to give the title compound 9 (35.8 mg, 85%) as a
1
All reactions were carried out under dry nitrogen unless other- white solid; mp 171.9–173.8 °C; H NMR (DMSO-d , 400 MHz)
6
1
3
wise indicated. Commercially available reagents were used δ 7.43 (s, 1H), 7.36–7.23 (m, 5H), 5.46 (s, 2H). C NMR
without further purification. Solvents and gases were dried (DMSO-d , 100 MHz) δ 137.6, 128.9, 128.2, 128.1, 126.3, 52.1.
6
1
9
11
according to standard procedures. Organic solvents were evap-
F NMR (DMSO-d , 376 MHz) δ −135.6. B NMR (DMSO-d6,
6
orated with reduced pressure using a rotary evaporator. 128 MHz) δ 2.19.
Analytical thin layer chromatography (TLC) was performed
4-(1-Benzyl-1H-1,2,3-triazol-4-yl)benzonitrile (14) (Table 3).
using glass plates precoated with silica gel (0.25 mm). TLC A sealed tube was charged with potassium (1-benzyl-1H-1,2,3-
plates were visualized by exposure to UV light (UV), and then triazol-4-yl)trifluoroborate 7 (40.0 mg, 150 μmol), 4-bromobenzo-
2 3
were visualized with a p-anisaldehyde stain followed by brief nitrile (18.0 mg, 98.9 μmol), Pd (dba) (3.70 mg, 4.04 μmol),
heating on a hot plate. Flash column chromatography was per- SPhos (3.30 mg, 8.03 μmol) and Na CO (21.0 mg, 198 μmol).
2
3
formed using silica gel 60 (230–400 mesh, Merck) with the The tube was sealed with a cap and purged with argon gas.
1
11
13
19
indicated solvents. H, B, C and F spectra were recorded Ethanol (1 mL) was added via a syringe and the reaction was
on Bruker 300, Bruker 400 (376 MHz) or Varian 300 NMR carried out at 85 °C for 18 h under the protection of argon gas.
1
spectrometers. H NMR spectra are represented as follows: Then, the reaction mixture was allowed to cool down to room
chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, temperature and filtered through a thin pad of silica gel
q = quartet, m = multiplet), integration, and coupling constant (eluting with EtOAc) and the filtrate was concentrated under
1
(
J) in hertz (Hz). H NMR chemical shifts are reported relative reduced pressure. The crude product was purified by column
1
3
3
to CDCl (7.26 ppm). C NMR spectra were recorded relative chromatography on silica gel (EtOAc–n-hexane = 1 : 3) to give
to the central line of CDCl3 (77.0 ppm). F NMR chemical the title compound 14 (25.7 mg, 99.9%) as a white solid; mp
shifts were referenced to external CFCl
1
9
11
1
3 3
(0.0 ppm). B NMR 140.4–142.0 °C; H NMR (CDCl , 400 MHz) δ 7.90 (d, J =
spectra at 128 MHz were obtained on a spectrometer equipped 8.5 Hz, 2H), 7.77 (s, 1H), 7.66 (d, J = 8.5 Hz, 2H), 7.38 (m, 3H),
1
1
13
with the appropriate decoupling accessories. All B NMR 7.31 (m, 2H), 5.58 (s, 2H); C NMR (CDCl , 100 MHz) δ 146.3,
3
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1
1
34.9, 134.2, 132.6, 129.2, 129.0, 128.1, 126.0, 120.7, 118.7,
11.4, 54.4.
t-Butyl-3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-
1,2,3-triazole-1-yl)pyrrolidine-1-carboxylate (3a). Following the
tert-Butyl 3-azidopyrrolidine-1-carboxylate (7). To a solution same procedure as that used for the synthesis of 14, the
of t-butyl-3-(methylsulfonyloxy)pyrrolidine-1-carboxylate (0.74 g, reaction of potassium 1-(1-(t-butoxycarbonyl)pyrrolidin-3-yl)-
2
6
8
.78 mmol) in DMF (7 mL) was added NaN3 (0.45 mg, 1H-1,2,3-triazole-4-yl trifluoroborate 4 (31.4 mg, 116 μmol),
.95 mmol) in DMF (7 mL). The reaction mixture was stirred at 1-bromo-4-fluoro-2-(3,4-dichlorobenzyloxy)-benzene 17a (21.0 mg,
0 °C for 3 h, then cooled to room temperature and diluted 77.5 μmol), Pd (dba) (2.20 mg, 3.09 μmol), SPhos (2.00 mg,
2 3
with water. The aqueous phase was then extracted with ethyl 6.19 μmol) and Na CO (13.0 mg, 155 μmol) in ethanol (1 mL)
2
3
acetate (3 × 20 mL). The organic layers were washed with brine, gave the title compound 3a (16.3 mg, 54%) as a colorless oil;
1
dried over anhydrous MgSO
4
and concentrated in vacuo. The
3
H NMR (CDCl , 400 MHz) δ 8.06 (dd, J = 3.1, 9.5 Hz, 1H), 7.93
resulting residue was purified by column chromatography on (s, 1H), 7.53 (d, J = 1.7 Hz, 1H), 7.50 (d, J = 8.2 Hz, 1H), 7.24
silica gel (EtOAc–n-hexane = 15 : 1) to give the title compound (dd, J = 2.0, 8.2 Hz, 1H), 6.97 (td, J = 3.1, 8.2 Hz, 1H), 6.89 (q,
1
7
(0.49 mg, 85%) as a colorless oil; H NMR (CDCl
3
, 300 MHz) J = 4.4 Hz, 1H), 5.12 (bs, 1H), 5.09 (s, 2H), 3.93 (q, J = 6.2 Hz,
δ 4.11 (m, 1H), 3.52–3.42 (m, 4H), 2.12–1.95 (m, 2H), 1.45 1H), 3.74 (bs, 1H), 3.57 (bs, 2H), 2.46 (bs, 1H), 2.36 (bs, 1H),
1
3
13
1
(
5
s, 9H); C NMR (CDCl
0.6, 50.3, 43.5, 43.2, 30.9, 30.1, 27.9.
Potassium 1-(1-(t-butoxycarbonyl)pyrrolidin-3-yl)-1H-1,2,3- 126.7, 121.8, 121.2 (d, J = 7.9 Hz), 115.1 (d, J = 23.4 Hz), 114.5
3
, 100 MHz) δ 153.7, 78.8, 60.1, 59.4, 1.44 (s, 9H); C NMR (CDCl
3
, 75 MHz) δ 157.6 (d, J = 237.8
Hz), 154.1, 150.5, 142.3, 136.7, 132.9, 132.5, 130.9, 129.3,
3
2
2
3
triazole-4-yl trifluoroborate (4). Following the same procedure (d, J = 25.0 Hz), 113.4 (d, J = 8.4 Hz), 80.0, 69.8, 59.3, 58.7,
as that used for the synthesis of 9, the reaction of tert-butyl-3- 51.4, 44.3, 43.9, 31.9, 31.0, 28.4.
azidopyrrolidine-1-carboxylate 7 (47.9 mg, 225 μmol), potass-
t-Butyl-3-(4-(5-chloro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-
(3b). Following
3.00 mg, 20.7 μmol), N,N-dimethylethylenediamine (4.40 μL, the same procedure as that used for the synthesis of 14, the
ium ethynyltrifluoroborate 6 (27.0 mg, 207 μmol), CuBr 1,2,3-triazole-1-yl)pyrrolidine-1-carboxylate
(
4
0.8 μmol) and Cs CO (67.0 mg, 207 μmol) in DMSO-d in an reaction of potassium 1-(1-(t-butoxycarbonyl)pyrrolidin-3-yl)-
2
3
6
NMR tube gave the title compound 4 (49.2 mg, 70%) as a 1H-1,2,3-triazole-4-yl trifluoroborate 4 (43.6 mg, 126 μmol),
1
6
white solid; mp 200.9–202.0 °C; H NMR (DMSO-d , 400 MHz) 1-bromo-4-chloro-2-(3,4-dichlorobenzyloxy)benzene 17b (32.6 mg,
δ 7.45 (s, 1H), 5.10 (m, 1H), 3.72 (q, J = 9.0 Hz, 1H), 3.54 (d, J = 84.6 μmol), Pd (dba) (3.10 mg, 3.38 μmol), SPhos (2.80 mg,
2
3
1
0.7 Hz, 1H), 3.41 (m, 2H), 2.37–2.24 (m, 2H), 1.39 6.82 μmol) and Na
2
CO (18.0 mg, 169 μmol) in ethanol (1 mL)
3
1
3
6
(s, 9H); C NMR (DMSO-d , 100 MHz) δ 154.0, 125.7, 79.3, gave the title compound 3b (23.6 mg, 53%) as a white solid;
1
9
1
5
8.1, 57.4, 51.9, 51.6, 44.7, 44.5, 31.8, 31.0, 28.5; F NMR mp 127.3–129.3 °C; H NMR (CDCl , 400 MHz) δ 8.33 (d, J =
3
1
1
(DMSO-d
6
, 376 MHz) δ −135.6; B NMR (DMSO-d
6
, 128 MHz) 2.6 Hz, 1H), 7.91 (s, 1H), 7.53 (d, J = 1.2 Hz, 1H), 7.50 (d, J =
δ 2.14.
8.2 Hz, 1H), 7.25–7.21 (m, 2H), 6.88 (d, J = 8.8 Hz, 1H), 5.10
1
-Bromo-4-fluoro-2-(3,4-dichlorobenzyloxy)-benzene
(17a). (bs, 3H), 3.93 (q, J = 6.2 Hz, 1H), 3.74 (m, 1H), 3.56 (bs, 2H),
1
3
To a solution of 2-bromo-4-fluorophenol (1.00 g, 5.26 mmol), 2.46 (bs, 1H), 2.36 (bs, 1H), 1.44 (s, 9H); C NMR (CDCl
,4-dichlorobenzylchloride (0.95 mL, 6.84 mmol) and K CO 75 MHz) δ 154.1, 152.8, 142.0, 136.5, 132.9, 132.5, 130.9, 129.3,
1.10 g, 7.85 mmol) in acetone (35 mL) was added KI (1.40 g, 128.5, 127.6, 126.9, 126.7, 121.9, 121.2, 113.3, 80.0, 69.5, 59.3,
.38 mmol). The reaction mixture was stirred at 60 °C for 24 h, 58.7, 51.4, 44.3, 44.0, 31.9, 31.0, 28.4.
then cooled to room temperature and diluted with water. The 3-(4-(5-Fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-tri-
3
,
3
(
8
2
3
aqueous phase was then extracted with DCM (3 × 30 mL). The azole-1-yl)pyrrolidinium 2,2,2-trifluoroacetate (18a). To a solu-
organic layers were washed with brine, dried over anhydrous tion of t-butyl-3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-
MgSO and concentrated in vacuo. The resulting residue was 1H-1,2,3-triazole-1-yl)pyrrolidine-1-carboxylate 17a (0.52 g,
4
purified by column chromatography on silica gel (EtOAc– 1.03 mmol) in DCM (5 mL) was added TFA (1.90 mL,
n-hexane = 1 : 15) to give the title compound 17a (1.38 g, 75%) 25.7 mmol). The reaction mixture was stirred at room tempera-
1
as a yellow oil; H NMR (CDCl
3
, 300 MHz) δ 7.56 (d, J = 1.9 Hz, ture for 0.5 h. The solvent was removed under reduced
1
7
H), 7.45 (d, J = 8.2 Hz, 1H), 7.31 (td, J = 2.6, 7.8 Hz, 2H), pressure to give the title compound 18a (0.57 g, 99%) as a
1
.99–6.93 (m, 1H), 6.84 (q, J = 4.6 Hz, 1H), 4.99 (s, 2H).
yellowish solid; mp 157.1–159.5 °C; H NMR (MeOH-d
4
,
1
-Bromo-4-chloro-2-(3,4-dichlorobenzyloxy)benzene
(17b). 400 MHz) δ 8.38 (s, 1H), 7.81 (dd, J = 3.2, 9.6 Hz, 1H), 7.59 (d,
Following the same procedure as that used for the synthesis J = 2.0 Hz, 1H), 7.50 (d, J = 8.4 Hz, 1H), 7.35 (d, J = 2.0, 8.4 Hz,
of 17a, the reaction of 2-bromo-4-chlorophenol (1.12 g, 1H), 7.08–7.01 (m, 2H), 5.50 (m, 1H), 5.19 (s, 2H), 3.91
1
3
5
.41 mmol), 3,4-dichlorobenzylchloride (1.37 mL, 7.03 mmol), (m, 2H), 3.64 (m, 2H), 2.67 (m, 1H), 2.53 (m, 1H); C NMR
1
K2CO3 (1.12 g, 8.12 mmol) and KI (1.43 g, 8.66 mmol) in (MeOH-d , 100 MHz) δ 157.3 (d, J = 236.0 Hz), 150.7, 142.2,
acetone (36 mL) gave the title compound 17b (1.89 g, 95%) as 137.6, 132.1, 131.5, 130.5, 129.3, 127.1, 123.9, 120.6 (d, J =
4
3
1
2
3
a yellowish oil; H NMR (CDCl
2
3
, 300 MHz) δ 7.56 (d, J = 2.3 Hz, 8.0 Hz), 115.0 (d, J = 24.0 Hz), 114.1 (d, J = 8.0 Hz), 113.3
3
H), 7.46 (d, J = 8.2 Hz, 1H), 7.29 (dd, J = 1.6, 8.3 Hz, 1H), 7.21 (d, J = 25.0 Hz).
(
dd, J = 2.5, 8.8 Hz, 1H), 6.80 (d, J = 8.8 Hz, 1H), 5.05 (s, 2H);
3-(4-(5-Chloro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-tri-
1
3
C NMR (CDCl
3
, 100 MHz) δ 153.4, 136.3, 133.1, 132.8, 132.2, azole-1-yl)pyrrolidinium 2,2,2-trifluoroacetate (18b). Following
1
30.7, 128.9, 128.3, 126.9, 126.2, 114.3, 113.0.
the same procedure as that used for the synthesis of 18a, the
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reaction of t-butyl-3-(4-(5-chloro-2-(3,4-dichlorobenzyloxy)-
1-(1-(4-Chlorobenzyl)pyrrolidin-3-yl)-4-(2-(3,4-dichlorobenzyloxy)-
phenyl)-1H-1,2,3-triazole-1-yl)pyrrolidine-1-carboxylate 17b (180 mg, 5-fluorophenyl)-1H-1,2,3-triazole (2ac). Following the same
3
43 μmol) and TFA (0.64 mL, 8.58 mmol) in DCM (1.7 mL) procedure as that used for the synthesis of 2aa, the reaction of
gave the title compound 18b (18.5 mg, 99%) as a yellowish 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-triazole-
1
solid; H NMR (MeOH-d , 400 MHz) δ 8.37 (s, 1H), 8.11 (d, J = 1-yl)pyrrolidinium 2,2,2-trifluoroacetate 18a (33.4 mg,
4
2
7
.4 Hz, 1H), 7.64 (d, J = 2.0 Hz, 1H), 7.55 (d, J = 8.4 Hz, 1H), 64.1 μmol), 4-chlorobenzaldehyde (18.0 mg, 128 μmol),
.39 (dd, J = 2.0, 8.0 Hz, 1H), 7.30 (dd, J = 2.6, 9.0 Hz, 1H), 7.12 CH CO H (1.10 μL, 19.2 μmol) and NaBH(OAc) (54.3 mg,
3
2
3
(
d, J = 8.8 Hz, 1H), 5.49 (m, 1H), 5.26 (s, 2H), 3.94 (dd, J = 1.6, 256 μmol) in THF (0.6 mL) gave the title compound 2ac
2.8 Hz, 1H), 3.84 (q, J = 6.5 Hz, 1H), 3.63 (m, 2H), 2.67 (m, (27.7 mg, 82%) as a yellow solid; mp 49.6–50.3 °C; H NMR
1
1
1
1
1
1
3
H), 2.51 (m, 1H); C NMR (MeOH-d
42.0, 137.5, 132.2, 131.6, 130.5, 129.3, 128.6, 127.1, 126.7, 7.55 (d, J = 1.8 Hz, 1H), 7.39 (d, J = 8.2 Hz, 1H), 7.25 (dd, J =
26.2, 124.0, 120.7, 114.2, 69.0, 58.9, 50.1, 44.6, 31.6. 1.5, 6.6 Hz, 1H), 7.19 (d, J = 8.3 Hz, 2H), 7.09 (d, J = 8.2 Hz,
-(1-Benzylpyrrolidin-3-yl)-4-(2-(3,4-dichlorobenzyloxy)-5-fluoro- 2H), 6.95 (m, 2H), 5.22 (m, 1H), 5.08 (s, 2H), 3.58 (q, J =
4 3
, 100 MHz) δ 153.2, (CDCl , 300 MHz) δ 8.13 (s, 1H), 8.06 (dd, J = 2.9, 9.6 Hz, 1H),
1
phenyl)-1H-1,2,3-triazole (2aa). To a solution of 3-(4-(5-fluoro- 14.1 Hz, 2H), 2.88 (m, 3H), 2.56 (m, 2H), 2.05 (m, 1H);
1
3
1
2
-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-triazole-1-yl)pyrroli-
C NMR (CDCl
3
, 75 MHz) δ 157.7 (d, J = 237.9 Hz), 150.6 (d,
4
4
dinium 2,2,2-trifluoroacetate 18a (25.0 mg, 47.9 μmol),
J = 1.9 Hz), 142.5 (d, J = 2.1 Hz), 136.7, 133.3, 132.9, 132.5,
3
CH CO H (0.55 μL, 9.59 μmol) and NaBH(OAc) (30.4 mg, 130.8, 129.9, 129.6, 128.6, 126.9, 121.9, 121.5 (d, J = 8.4 Hz),
44 μmol) in THF (0.5 mL) was added benzaldehyde (7.33 μL, 115.0 (d, J = 23.4 Hz), 114.4 (d, J = 25.1 Hz), 113.3 (d, J =
3
2
3
2
2
3
1
7
1.9 μmol). The reaction mixture was stirred at room tempera- 8.3 Hz), 77.2, 69.9, 59.5, 59.1, 58.5, 52.5, 32.7; HRMS-ESI (m/z):
+
ture for 24 h, and then diluted with water. The aqueous phase [M + H] calcd for C H Cl FN O 531.09160, found 531.09110.
2
6
23
3
4
was then extracted with DCM (3 × 3 mL). The organic layers
1-(1-(2,3-Dichlorobenzyl)pyrrolidin-3-yl)-4-(2-(3,4-dichloro-
were washed with brine, dried over anhydrous MgSO and benzyloxy)-5-fluorophenyl)-1H-1,2,3-triazole (2ad). Following
4
concentrated in vacuo. The resulting residue was purified by the same procedure as that used for the synthesis of 2aa, the
column chromatography on silica gel (EtOAc–n-hexane = 1 : 1) reaction of 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-
to give the title compound 2aa (14.8 mg, 62%) as a yellow 1,2,3-triazole-1-yl)pyrrolidinium
2,2,2-trifluoroacetate
18a
1
solid; mp 148.6–149.9 °C; H NMR (CDCl , 300 MHz) δ 8.16 (s, (34.3 mg, 65.8 μmol), 2,3-dichlorobenzaldehyde (23.0 mg,
3
1
8
H), 8.07 (dd, J = 3.0, 9.5 Hz, 1H), 7.54 (s, 1H), 7.37 (d, J = 132 μmol), CH
.2 Hz, 1H), 7.25–7.23 (m, 6H), 7.00–6.91 (m, 2H), 5.25 (55.8 mg, 263 μmol) in THF (0.6 mL) gave the title compound
3
CO
2
H (1.13 μL, 19.7 μmol) and NaBH(OAc)
3
1
(m, 1H), 5.05 (s, 2H), 3.66 (q, J = 13.1 Hz, 2H), 2.91 (m, 3H), 2ad (28.1 mg, 76%) as a yellow solid; mp 72.4–75.4 °C;
H
1
3
2
.58 (m, 2H), 2.06 (m, 1H); C NMR (CDCl
3
, 75 MHz) δ 157.7 NMR (CDCl
3
, 300 MHz) δ 8.20 (s, 1H), 8.06 (dd, J = 3.0, 9.6 Hz,
1
4
4
(d, J = 237.8 Hz), 150.6 (d, J = 2.0 Hz), 142.5 (d, J = 2.8 Hz), 1H), 7.47 (dd, J = 1.4, 9.7 Hz, 1H), 7.33 (t, J = 7.2 Hz, 2H),
1
1
36.7, 132.9, 132.5, 130.8, 129.5, 128.9, 128.6, 127.9, 126.8, 7.22–7.04 (m, 3H), 6.97 (td, J = 3.0, 8.2 Hz, 1H), 6.0 (q, J = 4.6
3
2
2
22.1, 121.5 ( d, J = 8.7 Hz), 115.0 (d, J = 23.3 Hz), 114.5 ( d, Hz, 1H), 5.28 (m, 1H), 5.09 (s, 2H), 3.74 (bs, 2H), 3.00 (bs, 2H),
3
13
3
J = 25.0 Hz), 113.4 (d, J = 8.4 Hz), 77.2, 69.9, 59.2, 59.0, 2.86 (bs, 1H), 2.59 (m, 2H), 2.04 (m, 1H); C NMR (CDCl ,
5
4
+
1
4
2.6, 32.7; HRMS-ESI (m/z): [M + H] calcd for C H Cl FN O 75 MHz) δ 157.7 (d, J = 237.8 Hz), 150.6 (d, J = 1.9 Hz), 142.6
26 24 2 4
4
97.13057, found 497.13019.
1
(d, J = 2.0 Hz), 136.8, 133.2, 132.8, 132.3, 132.2, 130.6, 129.4,
3
2
-(1-(4-Fluorobenzyl)pyrrolidin-3-yl)-4-(2-(3,4-dichlorobenzyloxy)- 128.4, 127.2, 126.8, 121.8, 121.6 (d, J = 8.5 Hz), 114.9 (d, J =
-fluorophenyl)-1H-1,2,3-triazole (2ab). Following the same 23.2 Hz), 114.4 (d, J = 25.1 Hz), 113.3 (d, J = 8.3 Hz), 77.2,
2
3
5
+
procedure as that used for the synthesis of 2aa, the reaction of 69.8, 60.0, 59.3, 56.7, 52.5, 32.8; HRMS-ESI (m/z): [M + H]
3
1
6
CH
2
-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-triazole- calcd for C26
-yl)pyrrolidinium 2,2,2-trifluoroacetate 18a (32.6 mg, 1-(1-(2,4-Dichlorobenzyl)pyrrolidin-3-yl)-4-(2-(3,4-dichloro-
2.5 μmol), 4-fluorobenzaldehyde (13.4 μL, 125 μmol), benzyloxy)-5-fluorophenyl)-1H-1,2,3-triazole (2ae). Following
CO H (1.07 μL, 18.8 μmol) and NaBH(OAc) (53.0 mg, the same procedure as that used for the synthesis of 2aa, the
50 μmol) in THF (0.6 mL) gave the title compound 2ab reaction of 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-
4 4
H22Cl FN O 565.05263, found 565.05217.
3
2
3
1
(
(
27.2 mg, 85%) as a yellow solid; mp 43.2–45.0 °C; H NMR 1,2,3-triazole-1-yl)pyrrolidinium
CDCl , 300 MHz) δ 8.13 (s, 1H), 8.07 (dd, J = 3.0, 9.6 Hz, 1H), (33.3 mg, 63.9 μmol), 2,4-dichlorobenzaldehyde (22.4 mg,
.55 (d, J = 1.7 Hz, 1H), 7.39 (d, J = 8.2 Hz, 1H), 7.26 (dd, J = 128 μmol), CH CO H (1.10 μL, 19.2 μmol) and NaBH
.8, 8.1 Hz, 1H), 7.13 (bs, 2H), 7.01–6.88 (m, 4H), 5.23 (m, 1H), (OAc)
.08 (s, 2H), 3.58 (q, J = 12.6 Hz, 2H), 2.86 (m, 3H), 2.56 (m, compound 2ae (25.3 mg, 70%) as a yellowish solid; mp
2,2,2-trifluoroacetate
18a
3
7
1
5
2
2
3
2
3
(54.2 mg, 256 μmol) in THF (0.6 mL) gave the title
1
3
1
1
H), 2.06 (m, 1H); C NMR (CDCl , 75 MHz) δ 162.3 (d, J = 120.0–121.3 °C; H NMR (CDCl , 300 MHz) δ 8.18 (s, 1H), 8.06
44.6 Hz), 157.7 (d, J = 237.8 Hz), 150.6 (d, J = 1.9 Hz), 142.5 (dd, J = 2.9, 9.6 Hz, 1H), 7.50 (s, 1H), 7.36 (d, J = 8.2 Hz, 1H),
3
3
1
4
4
(d, J = 2.0 Hz), 136.7, 132.9, 132.5, 130.8, 130.3, 129.6, 126.9, 7.29 (s, 1H), 7.23–7.07 (m, 3H), 6.97 (td, J = 3.0, 8.2 Hz, 1H),
3
2
1
21.9, 121.5 (d, J = 8.3 Hz), 115.4 (d, J = 21.2 Hz), 115.0 (d, 6.91 (q, J = 4.5 Hz, 1H), 5.24 (bs, 1H), 5.08 (s, 2H), 3.68 (bs,
2
2
3
13
J = 23.3 Hz), 114.4 (d, J = 25.0 Hz), 113.3 (d, J = 8.3 Hz), 77.2, 2H), 2.98–2.83 (m, 3H), 2.57 (m, 2H), 2.04 (m, 1H); C NMR
+
1
4
6
9.9, 59.4, 59.1, 58.5, 52.5, 32.7; HRMS-ESI (m/z): [M + H]
3
(CDCl , 75 MHz) δ 157.7 (d, J = 237.7 Hz), 150.6 (d, J =
4
calcd for C H Cl F N O 515.12115, found 515.12072.
2.0 Hz), 142.6 (d, J = 2.9 Hz), 142.5, 136.8, 134.6, 133.6, 132.9,
2
6
23
2 2 4
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1
32.4, 131.1, 130.7, 129.4, 129.3, 127.1, 126.8, 121.7, 121.6 (d, 8.02 (d, J = 14.6 Hz, 1H), 7.90 (s, 1H), 7.52–7.37 (m, 6H),
3
2
2
J = 8.2 Hz), 114.9 (d, J = 23.3 Hz), 114.4 (d, J = 25.0 Hz), 7.26–7.22 (m, 1H), 6.97 (td, J = 3.0, 8.2 Hz, 1H), 6.89 (q, J =
3
1
13.2 (d, J = 8.4 Hz), 77.2, 69.8, 59.9, 59.3, 55.4, 52.5, 32.7.
4.4 Hz, 1H), 5.18 (bs, 1H), 5.08 (s, 2H), 4.14–3.99 (m, 2H),
1
3
(
3-(4-(2-(3,4-Dichlorobenzyloxy)-5-fluorophenyl)-1H-1,2,3-triazole- 3.85 (bs, 1H), 3.65 (bs, 1H), 2.50 (bs, 2H);
C NMR
1
4
1
3
1
5
-yl)pyrrolidin-1-yl)(phenyl)methanone (2af). To a solution of (CDCl , 75 MHz) δ 168.9, 157.7 (d, J = 238.1 Hz), 150.6 (d, J =
-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-triazole- 1.7 Hz), 142.4, 136.7, 136.5, 134.2, 133.0, 132.6, 130.9,
-yl)pyrrolidinium 2,2,2-trifluoroacetate 18a (28.8 mg, 129.4, 128.7, 126.8, 122.3, 120.9 (d, J = 7.7 Hz), 115.3 (d, J =
5.2 μmol) and TEA (7.78 μL, 55.8 μmol) was added benzoyl 23.3 Hz), 114.5 (d, J = 25.1 Hz), 113.3 (d, J = 8.3 Hz), 77.2,
3
3
2
2
3
chloride (6.41 μL, 55.2 μmol). The reaction mixture was stirred 69.9, 59.3, 58.3, 54.2, 52.0, 47.7, 44.4, 32.7, 30.5; HRMS-ESI
+
at room temperature for 24 h, and then diluted with water. (m/z): [M + H] calcd for C26
3 4 2
H21Cl FN O 545.07086, found
The aqueous phase was then extracted with DCM (3 × 3 mL). 545.07018.
The organic layers were washed with brine, dried over an-
hydrous MgSO and concentrated in vacuo. The resulting sulfonyl)pyrrolidin-3-yl)-1H-1,2,3-triazole (2ai). Following the
residue was purified by column chromatography on silica gel same procedure as that used for the synthesis of 2af, the reac-
4-(2-(3,4-Dichlorobenzyloxy)-5-fluorophenyl)-1-(1-(phenyl-
4
(
(
(
EtOAc–n-hexane = 1 : 1) to give the title compound 2af tion of 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-1H-1,2,3-
18.7 mg, 67%) as a white solid; mp 55.4–57.5 °C; H NMR triazole-1-yl)pyrrolidinium 2,2,2-trifluoroacetate 18a (25.4 mg,
1
CDCl , 300 MHz) δ 8.04 (d, J = 7.3 Hz, 1H), 7.90 (s, 1H), 48.7 μmol), benzenesulfonyl chloride (6.22 μL, 48.7 μmol) and
3
7
6
.52–7.41 (m, 7H), 7.23 (s, 1H), 6.98 (td, J = 3.0, 8.2 Hz, 1H), TEA (6.68 μL, 49.2 μmol) in THF (0.5 mL) gave the title com-
.89 (q, J = 4.4 Hz, 1H), 5.21 (bs, 1H), 5.10 (s, 2H), 4.19–3.65 pound 2ai (10.6 mg, 40%) as a white solid; mp 136.3–137.6 °C;
1
3
1
(m, 4H), 2.51 (bs, 2H); C NMR (CDCl , 75 MHz) δ 170.1,
H NMR (CDCl , 300 MHz) δ 8.01 (dd, J = 3.1, 9.5 Hz, 1H), 7.90
3
3
1
1
1
9
57.7 (d, J = 238.0 Hz), 150.5, 142.4, 136.7, 135.9, 133.0, 132.6, (s, 1H), 7.79 (dd, J = 1.5, 8.1 Hz, 2H), 7.56–7.47 (m, 5H), 7.28
30.9, 130.4, 129.4, 128.4, 127.2, 126.7, 122.3, 120.9 (d, J = (m, 1H), 7.00 (td, J = 2.0, 4.9 Hz, 1H), 6.90 (q, J = 4.5 Hz, 1H),
.2 Hz), 115.3 (d, J = 23.4 Hz), 114.5 (d, J = 25.3 Hz), 113.4 5.09 (bs, 3H), 3.72 (m, 2H), 3.47 (m, 2H), 2.41 (m, 2H);
3
2
2
3
13
1
(d, J = 8.3 Hz), 77.2, 69.8, 65.8, 63.7, 59.3, 58.4, 54.2, 51.8,
C NMR (CDCl
3
, 75 MHz) δ 157.7 (d, J = 232.8 Hz), 150.5,
+
4
7.7, 44.3, 32.7, 30.5; HRMS-ESI (m/z): [M + H] calcd for 142.5, 136.7, 136.1, 133.1, 133.0, 132.6, 131.0, 129.5, 129.2,
3
2
C H Cl FN O 511.10984, found 511.10888.
127.4, 126.9, 121.7, 121.0 (d, J = 8.4 Hz), 115.2 (d, J =
2
6
22
2
4 2
2
3
(
3-(4-(2-(3,4-Dichlorobenzyloxy)-5-fluorophenyl)-1H-1,2,3-triazole- 23.2 Hz), 114.5 (d, J = 25.2 Hz), 113.3 (d, J = 8.3 Hz), 69.9,
+
1
-yl)pyrrolidin-1-yl)(4-fluorophenyl)methanone (2ag). Follow- 58.8, 53.4, 46.2, 31.5; HRMS-ESI (m/z): [M + H] calcd for
ing the same procedure as that used for the synthesis of 2af, C H Cl FN O S 547.07682, found 547.07700.
2
5
22
2
4 3
the reaction of 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)phenyl)-
H-1,2,3-triazole-1-yl)pyrrolidinium 2,2,2-trifluoroacetate 18a phenyl)sulfonyl)pyrrolidin-3-yl)-1H-1,2,3-triazole (2aj). Fol-
32.7 mg, 62.7 μmol), 4-fluorobenzoyl chloride (7.41 μL, lowing the same procedure as that used for the synthesis of
2.7 μmol) and TEA (11.4 μL, 81.5 μmol) in THF (0.6 mL) gave 2af, the reaction of 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)-
the title compound 2ag (31.2 mg, 94%) as a white solid; mp phenyl)-1H-1,2,3-triazole-1-yl)pyrrolidinium 2,2,2-trifluoroacetate
4-(2-(3,4-Dichlorobenzyloxy)-5-fluorophenyl)-1-(1-((4-fluoro-
1
(
6
1
1
1
8
3
2
2
11.8–113.0 °C; H NMR (CDCl , 300 MHz) δ 8.03 (d, J = 18a (32.9 mg, 63.1 μmol), 4-fluorobenzenesulfonyl chloride
3
2.3 Hz, 1H), 7.90 (s, 1H), 7.52 (d, J = 1.4 Hz, 2H), 7.48 (d, J = (12.3 mg, 63.1 μmol) and TEA (11.4 μL, 81.5 μmol) in THF
.2 Hz, 2H), 7.22 (bs, 1H), 7.07 (t, J = 7.8 Hz, 2H), 6.97 (td, J = (0.6 mL) gave the title compound 2aj (12.4 mg, 35%) as a
.0, 8.2 Hz, 1H), 6.89 (q, J = 4.5 Hz, 1H), 5.19 (bs, 1H), 5.09 (s, yellowish solid; mp 167.0–168.5 °C; H NMR (CDCl , 300 MHz)
H), 4.16–4.01 (m, 2H), 3.85 (bs, 1H), 3.65 (bs, 1H), 2.51 (bs, δ 8.03 (dd, J = 3.1, 9.5 Hz, 1H), 7.89 (s, 1H), 7.79 (m, 2H),
H); C NMR (CDCl , 75 MHz) δ 169.0, 163.8 (d, J = 249.4 7.54–7.52 (m, 2H), 7.28 (m, 1H), 7.17 (t, J = 8.5 Hz, 2H), 7.00
3
Hz), 157.7 (d, J = 238.2 Hz), 150.5, 142.4, 136.7, 133.0, 132.6, (td, J = 3.0, 8.2 Hz, 1H), 6.91 (q, J = 4.5 Hz, 1H), 5.09 (bs, 3H),
32.0, 130.9, 129.6 (d, J = 8.5 Hz), 129.4, 126.8, 122.2, 120.9 3.72 (m, 2H), 3.48 (t, J = 7.1 Hz, 2H), 2.43 (m, 2H); C NMR
d, J = 8.4 Hz), 115.6 (d, J = 19.9 Hz), 115.3 (d, J = 22.9 Hz), (CDCl , 75 MHz) δ 165.4 (d, J = 254.1 Hz), 157.7 (d, J =
3
14.5 (d, J = 25.2 Hz), 113.3 (d, J = 8.4 Hz), 77.2, 69.8, 234.5 Hz), 150.5, 142.5, 136.6, 132.8 (d, J = 25.8 Hz), 132.3,
9.3, 58.4, 54.3, 52.0, 47.8, 44.5, 32.7, 30.5; HRMS-ESI (m/z): 131.0, 130.2 (d, J = 9.3 Hz), 129.5, 126.9, 121.7, 120.9 (d, J =
H] calcd for
29.09987.
2 2 4 3
4-Chlorophenyl)(3-(4-(2-(3,4-dichlorobenzyloxy)-5-fluoro- 31.6; HRMS-ESI (m/z): [M + H] calcd for C25H20Cl F N O S
1
3
13
1
1
3
13
1
(
1
5
3
2
2
1
1
2
3
2
3
3
+
2
2
[M
+
C
26
H
21Cl
2
F
2
N
4
O
2
529.10041, found 8.5 Hz), 116.5 (d, J = 22.3 Hz), 115.3 (d, J = 23.1 Hz), 114.5
2
3
5
(d, J = 25.3 Hz), 113.2 (d, J = 8.3 Hz), 69.8, 58.8, 53.5, 46.2,
+
(
phenyl)-1H-1,2,3-triazole-1-yl)pyrrolidin-1-yl)methanone (2ah). 565.05263, found 565.05216.
Following the same procedure as that used for the synthesis of
2
af, the reaction of 3-(4-(5-fluoro-2-(3,4-dichlorobenzyloxy)-
phenyl)-1H-1,2,3-triazole-1-yl)pyrrolidinium 2,2,2-trifluoro-
acetate 18a (33.4 mg, 64.1 μmol), 4-chlorobenzoyl chloride
Biological evaluation
JC-1 mitochondrial membrane potential assay
(8.21 μL, 64.1 μmol) and TEA (11.6 μL, 83.3 μmol) in THF
(
0.6 mL) gave the title compound 2ah (30.5 mg, 87%) as a HT-22 cells (30 000 per well) were seeded into a clear 96-well
1
white solid; mp 137.4–140.6 °C; H NMR (CDCl , 300 MHz) δ plate (FALCON) at 200 μL per well one day prior to assay.
3
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Organic & Biomolecular Chemistry
7
50 μM of JC-1 (Stratagene) in DMSO stock solution was dis-
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a final concentration of 7.5 μM JC-1 per well. The medium was
removed from the plate, and 100 μL per well of JC-1 was
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CYP inhibition assay
The test compound (40 μL of a 25 μM solution of the com-
pound in distilled water) into a 96-well plate and then 50 μL of
the Master Pre-Mix (CYP450 BACULOSOMES® Reagent and
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2
2
0 min at 37 °C to allow the compound to interact with the
1
CYP450. The reaction was initiated by adding Vivid® CYP450
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19 Y. S. Kim, S. H. Jung, B.-G. Park, M. K. Ko, H.-S. Jang,
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substrate/NADP buffer (10 μL). The remaining enzyme activity
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Acknowledgements
This research was supported by the Korea Institute of Science
and Technology (KIST-2E24670, 2E25023, 2E24510, 2V03370)
and the National Research Foundation of Korea (NRF-
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013R1A1A2005550 and NRF-2014M3C1A3054141) funded by
the Ministry of Science, ICT and Future Planning. We thank
Mr Beoung-Geon Park and Ms Min Kyung Ko for the
JC-1 assay and the CYP stability experiments. We thank Dr
Jungyeob Ham for helpful discussion on organotrifluoroborates.
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