Design and synthesis of potent hydroxamate inhibitors with increased selectivity within the gelatinase family

Article abstract of DOI:10.1039/c4ob01516a

MMP-2 is a validated target for the development of anticancer agents. Herein we describe the synthesis of a new series of potent phenylalanine derived hydroxamates, with increased MMP-2/MMP-9 selectivity compared to analogous hydroxamates described previously. Docking and molecular dynamics experiments have been used to account for this selectivity, and to clarify the role of the triazole ring in the binding process. This journal is

Full text of DOI:10.1039/c4ob01516a

Organic &
Biomolecular Chemistry
View Article Online
View Journal | View Issue
PAPER
Design and synthesis of potent hydroxamate
inhibitors with increased selectivity within the
gelatinase family†
Cite this: Org. Biomol. Chem., 2015,
13, 142
José María Zapico,a Anna Puckowska,a,b Kamila Filipiak,a,c Claire Coderch,a
Beatriz de Pascual-Teresa*a and Ana Ramos*a
MMP-2 is a validated target for the development of anticancer agents. Herein we describe the synthesis
of a new series of potent phenylalanine derived hydroxamates, with increased MMP-2/MMP-9 selectivity
compared to analogous hydroxamates described previously. Docking and molecular dynamics experi-
ments have been used to account for this selectivity, and to clarify the role of the triazole ring in the
binding process.
Received 18th July 2014,
Accepted 1st October 2014
DOI: 10.1039/c4ob01516a
www.rsc.org/obc
of sequence homology and substrate specificity: collagenases,
gelatinases, stromelysins, matrilysines and membrane-type
Introduction
Proteases are classified into serine proteases, cysteine pro- MMPs (MT-MMPs).5
teases, aspartate proteases and metalloproteinases, based on
Basically, all MMPs have been linked to disease develop-
differences in the hydrolysis mechanism of peptide bonds.1 ment,6,7 mainly in cardiovascular disorders,8–10 arthritis,11
The human degradome (proteases produced by cells) consists acute lung injury,12 and cancer.13–15
of at least 569 proteases and homologues, with metallo-
proteinases representing the largest class (194 described in important role in cancer. They are over-expressed or deregu-
humans).2 lated in a variety of malignant tumors.16 It has been shown, in
Gelatinase A (MMP-2) and gelatinase B (MMP-9) play an
The Metzincin superfamily of metalloproteinases can, in an experiment in MMP-2 knockout mice, that angiogenesis
turn, be classified into the following four subfamilies, accord- and tumour progression can be controlled by inhibiting the
ing to the slight differences in their catalytic site and the pres- activity of this enzyme, suggesting the use of MMP-2 inhibitors
ence of additional domains: matrix metalloproteinases for chemotherapy of cancer and other diseases.17 However,
(MMPs), adamalysins (ADAM, ADAMTS and class III snake while MMP-2 is
a validated target in cancer therapy,
venom proteins), astacins (BMP1/TLL proteins and meprins) MMP-9 has both pro- and anti-tumorigenic effects, and is an
and bacterial serralysins.3 Metzincins are distinguished by a anti-target protein in advanced stages of the disease.18
highly conserved HEXXHXXGXXH domain that bears three his-
tidine residues that bind a zinc atom at the active site.4
A large number of MMP inhibitors (MMPIs) have been
reported so far. MMPIs containing a Zinc Binding Group
The 26 MMPs described so far in the vertebrate family can (ZBG) and a lipophilic chain (called the P1′-segment) which
be classified into several subfamilies according to their degree interacts with the hydrophobic S1′ pocket are very effective.
The latter is considered the “selectivity pocket”, as it is the
region where MMPs exhibit the largest differences.19–22
aDepartamento de Química y Bioquímica, Facultad de Farmacia, Universidad CEU
In our research group we are interested in the design of
San Pablo, Urbanización Monteprincipe, 28668 Madrid, Spain.
MMP-2 inhibitors with selectivity over other metalloproteinases,
E-mail: bpaster@ceu.es, aramgon@ceu.es; Fax: (+34) 913510496;
especially over MMP-9. Because the active sites of both enzymes
Tel: (+34) 913724724, (+34) 913724796
bDepartment of Organic Chemistry, Faculty of Pharmacy, Medical University
of Bialystok, Poland
cDepartment of Molecular Biology, Faculty of Biotechnology and Natural Sciences,
are very similar, it is necessary to carefully select the fragment
that has to interact with the S1′ pocket. Our approach is based
on the use of Cu(I)-catalyzed azide–alkyne cycloaddition, one of
the most effective click reactions, to easily connect the selected
ZBG with different non-polar P1′ substituents in order to
explore the S1′ pocket. Following this strategy we have obtained
inhibitors with high potency and MMP-2/MMP-9 selectivity
The John Paul II Catholic University of Lublin, 20-718 Lublin, Poland
†Electronic supplementary information (ESI) available: Torsional energies of the
C
sp2–Csp2 and Csp2–Nsp2 scan; and per-residue energy decomposition of the four
systems. 1H NMR and 13C NMR spectra of compounds 1a–g, 7, 13 and 14. See
DOI: 10.1039/c4ob01516a
142 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
biphenyl group attached to N1, instead of the C-4 position that
is occupied in 1a–g. The synthetic pathway for 7 (Scheme 2)
started from ( ) phenylalanine methyl ester hydrochloride,
which was transformed into sulphonamide 8 by reaction with
pipsyl chloride. Sonogashira cross-coupling reaction with ethy-
nyltrimethylsilane gave 9, which was deprotected under basic
conditions to give 10, and was subsequently transformed into
11 by coupling with NH2OTHP. The terminal alkyne was
clicked with 4-azidobiphenyl28 to give triazole 12, which was
deprotected to give the desired compound 7.
With the aim of improving the solubility of this class of
compounds, a basic side chain was introduced into the sul-
phonamide nitrogen atom. We chose a morpholinoethyl
moiety, as this fragment was used before to improve the solu-
bility of valine-derived hydroxamates.29
Thus, compounds 13 and 14 were synthesized following
the synthetic pathway shown in Scheme 3. Carboxylic acid 4
was protected as tert-butyl ester 15, and after alkylation with
4-(2-chloroethyl)morpholine in the presence of K2CO3, 16 was
obtained. A sequence of tert-butyl deprotection to give 17 and
coupling of the carboxylic acid with O-THP hydroxylamine
gave azide 18. The CuAAC reaction with two different alkynes
gave the corresponding triazoles 19–20 which were converted
into hydroxamates 13 and 14 by acidic O-THP deprotection.
Fig. 1 Structure and inhibitory activity of (A) clicked MMP-2 selective
inhibitors and (B) BiPS.
Biological evaluation
The inhibitory activities of hydroxamates 1a–g, 7, 13 and 14
against MMP-2 and MMP-9 were determined by the colori-
metric method using a thiopeptide as a chromogenic substrate
(Enzo Life Science Inc.). The assay conditions were similar to
those described before [Fabre, 2013 #34].24 The results are col-
lected as IC50 in Table 1.
All racemic compounds showed potent inhibitory activity
against MMP-2, which was higher than the one reported for
BiPS (IC50 = 17 nM).26
(Fig. 1A).23–25 The potent but not selective MMPI (2R)-[(4-bi-
phenylylsulfonyl)amino]-N-hydroxy-3-phenylpropionamide (BiPS)26
(Fig. 1B) has been the starting point for the design of the new
series of inhibitors described herein. With the aim of increas-
ing the selectivity between both gelatinases we have followed
the same approach based on click chemistry.
An exception was 1d, where the P1′ side chain is too polar
to interact with the hydrophobic S1′ pocket of the enzyme.
This result was expected, as we also found the lack of activity
Results and discussion
Chemistry
Hydroxamates 1a–g were synthesized following the pathway with this P1′ group in our previous studies.23
outlined in Scheme 1. Compound 2 was obtained as described
The best result in potency and selectivity was found for 1b,
previously,27 starting from phenylalanine and 4-nitrobenzene- with an IC50 of 1.3 nM for MMP-2 and almost 100-fold less
sulfonyl chloride under basic conditions. The nitro group was activity against MMP-9. This result shows that our click based
reduced by catalytic hydrogenation to give amino acid 3, which strategy is a useful approach to improve the profile of this type
was transformed into azide 4 by reaction with tert-butyl nitrite of inhibitor, especially in the search for ligands capable of
and azidotrimethylsilane. Reaction of the carboxylic acid with differentiating between the two gelatinases.
O-THP protected hydroxylamine, using EDCI as an amide
coupling agent, gave hydroxamate 5. Copper(I) catalyzed alanine-derived hydroxamates, it was found that the preferred
Huisgen cycloaddition (CuAAC) between and different stereochemistry at the stereogenic centre corresponded to the
alkynes gave compounds 6a–g, which were deprotected to R-isomer, which was more potent than the racemate.30
obtain the final hydroxamates 1a–g. similar result was reported for BiPS, which was 28-fold more
(R) and (S) enantiomers of hydroxamates 1b, 1c and 1f were active in MMP-9 than the S-isomer.26
In the previously reported activity against MMP-3 of phenyl-
5
A
prepared separately following the same pathway starting from
D or L phenylalanine.
In order to verify if the configuration of the stereogenic
centre has an effect also on the inhibitory activity of 1b, 1c and
In order to study the effect of the triazole ring on the 1f, both enantiomers of these compounds were synthesized
activity, hydroxamate 7 was synthesized. This compound has a and tested against both gelatinases. The results show that
different substitution pattern in the triazole ring, with the (R)-1b is 293-fold more potent against MMP-2 than (S)-1b, and
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 143

View Article Online
Paper
Organic & Biomolecular Chemistry
Scheme 1 Synthesis of triazoles 1a–g. (a) NaOH–H2O; (b) H2, Pd/C, MeOH; (c) t-BuONO, TMSiN3, acetonitrile, 0 °C; (d) O-(tetrahydro-2H-pyran-2-
yl)hydroxylamine, EDCI, HOBt, NMM, DMF; (e) alkyne, CuSO4, sodium ascorbate, DMF or t-BuOH–H2O; (f) 4 M HCl–dioxane, MeOH.
Scheme 2 Synthesis of triazole 7: (a) pipsyl chloride, NMM, CH2Cl2; (b) TMSCCH, CuI, Et3N, Ph3P, Pd/C, reflux; (c) 1: KOH, dioxane, rt, 2: citric acid
20%; (d) NH2OTHP, EDCI, HOBt, NMM, DMF; (e) biphenylazide, CuSO4·5H2O, sodium ascorbate, DMF, (f) 4 M HCl–dioxane, MeOH.
144 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
Scheme 3 Synthesis of triazoles 13 and 14. (a) 2-Methylpropene, H2SO4, DCM, 86%; (b) 4-(2-chloroethyl)morpholine, K2CO3, DMF, 85%; (c) TFA,
thioanisole, DCM, 80%; (d) NH2OTHP, EDC, HOBt, DMAP, DMF, 91%; (e) alkyne, CuSO4, sodium ascorbate, DMF; (f) HCl, dioxane, 60–75%.
Table 1 MMP inhibition activities for compounds 1a–g, 7, 13 and 14
a
a
MMP-2 IC50
(nM)
MMP-9 IC50
(nM)
Selectivity for
MMP-9/MMP-2
Compound
R1
R2
Rac.-1a
Rac.-1b
(R)-1b
(S)-1b
Rac.-1c
(R)-1c
3-FC6H4
H
H
H
H
H
H
H
H
H
H
H
H
H
0.27
1.3
0.75
220
0.88
0.32
49
>500
0.42
2.2
1.08
>500
8.18
1.32
2.66
1.99
3.6
124
13
95
78
—
2.4
3.4
—
—
2.8
41
34
—
46
4
4-C6H5-C6H4
4-C6H5-C6H4
4-C6H5-C6H4
(CH3)2N-C6H4
(CH3)2N-C6H4
(CH3)2N-C6H4
PhSO2NHCONHCH2
4-CH3O-C6H4
4-C6H5-O-C6H4
4-C6H5-O-C6H4
4-C6H5-O-C6H4
4-C5H11-C6H4
58.5
>1000
2.11
1.06
>1000
>1000
1.16
88
36.8
>1000
372
5.54
6.34
29.9
(S)-1c
Rac.-1d
Rac.-1e
Rac.-1f
(R)-1f
(S)-1f
Rac.-1g
Rac.-7
(R)-13
(R)-14
4-C6H5-C6H4
4-C6H5-O-C6H4
2-Morpholinoethyl
2-Morpholinoethyl
2.4
15
a IC50 values on the nM scale were determined using a colorimetric assay. Enzymatic data are the main values from three independent
experiments. SD are within 10%.
1.7-fold more potent than the racemic form, showing that the
Compounds 13 and 14, where a basic chain was introduced
racemate activity is mainly due to the R-isomer. However, the into the sulphonamide nitrogen atom, presented better solubi-
MMP-2/MMP-9 selectivity of (R)-1b is slightly diminished with lity during sample preparation. However, although the inhi-
respect to the racemic mixture because the S-isomer was com- bition against MMP-2 was kept at the same level, the
pletely inactive in MMP-9 (IC50 > 1000). A similar effect was inhibitory activities against MMP-9 were increased giving a
observed for 1c and 1f.
worse selectivity profile.
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 145

View Article Online
Paper
Organic & Biomolecular Chemistry
triazole to the end of the P1′-segment, whereas compound 7
will form an angle of around 45° between the triazole and the
P1′-segment.
Table 2 Inhibitory activity (IC50 values) ofRac.-1b, Rac.-1f and Rac.-1g
towards a panel of metalloproteinases
1ba (nM)
1fa (nM)
1ga (nM)
The docking experiments for compound 1b were carried
out with a deprotonated hydroxamic acid moiety on MMP-2
and MMP-9, and with a protonated side chain of Glu404. The
obtained poses were overall similar to those obtained in our
previous work,35 so these complexes were used to build the
complexes of 7 with MMP-2 and MMP-9 by changing the
atom type in the triazole ring and allowing the geometries to
relax in the molecular mechanics force field. During the
10 ns molecular dynamics (MD) simulations we monitored
the per-residue protein–ligand interactions, especially those
established between the P1′-segment and the S1′ pocket.
Compounds 1b and 7 establish mainly van der Waals inter-
actions in the complexes with both MMP-2 and MMP-9 (ESI†
Fig. 2). Both compounds establish strong van der Waals inter-
MMP-1
MMP-2
MMP-3
MMP-7
MMP-8
MMP-9
MMP-10
MMP-12
MMP-13
MMP-14
>10 000
1.3
50
>500
>500
124
181
3.8
<5
555.7
>10 000
2.2
33.4
>1000
128.8
88
103.4
2
1.5
>1000
8.2
170
>1000
450
372.5
336
14.2
36.8
>200
256.6
a Enzymatic data are the mean values from two independent
experiments. SD are within 10%.
Interestingly, the same effect was observed for compound 7. actions with the amino acids of the first segment of the
This compound was obtained through a click reaction between Ω-loop within both MMPs, especially with Ile424(MMP-2)/
4-azidobiphenyl and an alkyne bearing the hydroxamate ZBG. Met422(MMP-9) that interacts with the triazole through the
The structure is closely related to 1b, with the only difference backbone; and Tyr425(MMP-2)/Tyr423(MMP-9) and Thr426
being in the substitution pattern of the triazole ring: the (MMP-2)/Arg424(MMP-9) that stack their side chains with the
biphenyl group in 7 is attached to the N1 of the triazole, triazole and biphenyl moieties. The slight difference in the
instead of the C-4 position that is occupied in 1b. While the interaction energy between both compounds and the side
activity of 7 against MMP-2 was maintained (IC50 = 1.32 nM), a chain of Arg424 in the case of MMP-9 can be explained by the
high increase in the activity against MMP-9 was observed difference in flexibility at the end of the P1′-segment men-
(IC50 = 5.54 nM) compared to the activity of 1b (Rac.-1b: IC50
124 nM; (R)-1b: 58.5 nM), with the corresponding loss of ment of 1b is more rigid than the Csp2–Nsp2 bond present in
selectivity.
7, which induces fewer fluctuations in the interaction with
=
tioned before. The Csp2–Csp2 bond present in the P1′ frag-
Compounds 1b, 1f and 1g, showing a promising selectivity the highly flexible side chain of Arg424, resulting in a better
profile within gelatinases, were chosen for the analysis of their interaction energy for 1b compared to 7. The interactions
activity towards other metalloproteinases (Table 2). The established between compounds 1b and 7 and the last
obtained profile showed that these compounds are devoid of segment of the Ω-loop can account for the lack of selectivity
activity towards MMP-1, whose inhibition is hypothesized to of compound 7. In our previous work we proposed that the
be connected with the musculoskeletal syndrome,31,32 and selectivity of this type of molecules, especially the biphenyl
have lower activity towards MMP-8, an enzyme whose inhi- derivatives, arises from the presence of the Phe431-
bition could enhance tumourigenesis and metastasis.33 More- Arg432 motif in MMP-2, which is mutated to Pro429-Pro430
over, 1b and 1f displayed good activity towards MMP-13, an in MMP-9. This difference makes the Ω-loop more rigid in
enzyme whose inhibition is targeted in the treatment of osteo- MMP-9 than in MMP-2.25 In the case of MMP-2, both com-
arthritis, while having much lower potency towards MMP-14, pounds interact with the side chain of Phe431 (Fig. 2). Inter-
proposed recently as an anti-target in the treatment of this estingly, the study of the MD trajectories and the minimized
disease.34
cooled structure obtained after the 10 ns simulations showed
In order to explain the difference in selectivity between that compound 7, having a torsion of around 45° between the
compounds 1b and 7 we first studied both separately by triazole and the P1′-segment, due to the Csp2–Nsp2 bond, is
means of ab initio quantum mechanics (QM) methods. able to adopt more easily the shape of the S1′ pocket, esta-
Despite being structurally very similar, the difference in the blishing a van der Waals interaction with Pro429 (Fig. 2). This
substitution pattern of the triazole determines the relative interaction is absent in compound 1b which is flatter and
orientation of the P1′-segment with the rest of the compound. has less flexibility. This difference could explain the different
The main difference arises from the energy profile of the di- in vitro activity observed for both compounds. Although we
hedral angle that describes the torsion around Csp2–Csp2 and have explained the difference in selectivity between com-
Csp2–Nsp2. The first dihedral angle presents energy minima at pounds 1b and 7, we were not able to give the rationale of the
15° and global maxima of 3.3 kcal mol−1 at 90°, whereas the difference in binding affinity between both enantiomers of
dihedral angle between Csp2–Nsp2 presents energy minima compound 1b as they did not show any significant differ-
between 30–45°, a local maximum of 0.7 kcal mol−1 at 0°, ences in the dynamic behaviour and interactions with
and a global maximum of 1.6 kcal mol−1 at 90° (ESI† Fig. 1). the two proteins in the time span and conditions of our
This means that compound 1b will be almost flat from the simulations.
146 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
Fig. 2 PyMOL cartoon representation of the complexes between MMP2 (green) and MMP9 (cyan) and compounds 1b (magenta) and 7 (yellow)
respectively. For the sake of clarity, only polar hydrogens are displayed; and only the side chains of the amino acids that stabilize the ZBG-end and
those that bring about the most different interactions in the Ω-loop are shown as sticks.
best-obtained result for each ligand in each complex was con-
sidered for analysis of the ligand–receptor interactions and
subsequent molecular modeling simulations.
Experimental section
Molecular modeling
The proteins were prepared and the docking experiments were
For the MD simulations the charge distribution for the
carried out as in the previous work.25 The ligands (compounds ligands was obtained by fitting the quantum mechanically cal-
1b and 7) were built using the Maestro LigPrep module (http:// culated (RHF/6-31G**//RHF/3-21G*) molecular electrostatic
www.Schrodinger.com). pKa of titratable groups were calcu- potential (MEP) of the geometry-optimized molecules to a
lated using the Sparc pKa online calculator,36 and the non-pro- point charge model, as implemented in Gaussian 03 (Gaus-
tonated form of the hydroxamate was used for the docking sian, Inc., Wallingford, CT). Consistent bonded and non-
calculations making use of the Glide module.37–39 The center bonded AMBER parameters for both molecules were assigned
of the box was positioned on the catalytic zinc ion present in by analogy or through interpolation from those already present
the active site. The box size was set up to enclose the ligand- in the AMBER database (ff03). Each MMP molecular system
binding domain to ensure an adequate exploration of the was immersed in a truncated octahedron containing ∼10 000
binding poses. The docking procedure was performed with XP TIP3P water molecules40 and four Na+ ions41 to achieve system
(extra precision) mode, and a van der Waals radii scale factor electroneutrality. The sander and pmemd modules of the
of 1.0/0.8 for the receptor and the ligand, respectively. The AMBER12 suite (http://ambermd.org/) were used for the
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 147

View Article Online
Paper
Organic & Biomolecular Chemistry
restrained and unrestrained MD simulations, respectively. Peri- (50 mL) and 10% Pd/C (200 mg) were introduced into a Parr
odic boundary conditions were applied and electrostatic inter- shaker apparatus, and maintained under a hydrogen pressure
actions were treated using the smooth particle mesh Ewald of 60 p.s.i for 5 h at room temperature. Palladium was filtered
method42 with a grid spacing of 1 Å. The cutoff distance for off and the solvent was removed to afford after recrystallization
the non-bonded interactions was 9 Å, the SHAKE43 algorithm from EtOH–H2O (R)-3 (2.17 g, 98%) as a yellowish solid,
was applied to all bonds, and an integration step of 2.0 fs was mp 189–190 °C.
used throughout. After an initial energy minimization of the
(2S)-2-{[(4-Aminophenyl)sulfonyl]amino}-3-phenylpropanoic
water molecules and counterions, the system was heated to acid ((S)-3). A solution of (S)-227 (2.75 g, 7.84 mmol) in EtOH
300 K in 25 ps, after which the solvent was allowed to redistri- (50 mL) and 10% Pd/C (225 mg) were introduced into a Parr
bute around the positionally restrained solute for 220 ps. After shaker apparatus, and maintained under a hydrogen pressure
this time, the system was allowed to move freely so as to of 60 p.s.i. for 5 h at room temperature. Palladium was filtered
explore the mutual adaptation between the ligand and the off and the solvent was removed to afford after recrystallization
protein. Snapshots from each 10 ns MD trajectory were col- from EtOH–H2O (S)-3 (2.49 g, 99%) as a yellowish solid, mp
lected every 20 ps for further analysis carried out with the ptraj 189–190 °C.
module of AMBER to monitor the hydrogen bonding distances
2-{[(4-Azidophenyl)sulfonyl]amino}-3-phenylpropanoic acid
between the ligands and the protein. The per-residue energy (4). Compound 3 (1.45 g, 4.53 mmol) was suspended in an-
decomposition of the 10 ns MD trajectory was carried out hydrous CH3CN (30 mL) under argon and cooled to 0 °C in an
using the ISM program.44,45
ice bath. To this suspension was added t-BuONO (0.80 mL,
5.45 mmol), followed by TMSN3 (0.72 mL, 5.42 mmol) drop-
wise. The reaction mixture was stirred at 0 °C for 30 min,
Chemistry
General procedures. Melting points (uncorrected) were and at room temperature for 6 h. Then, it was evaporated to
determined on a Stuart Scientific SMP3 apparatus. Infrared dryness, and the residue was purified by column chromato-
(IR) spectra were recorded with a Perkin-Elmer Spectrum 100 graphy on silica gel (DCM–MeOH 5% MeOH) to afford 4 (1.4 g,
1
Series infrared spectrophotometer. H and 13C NMR data were 89%) as a yellowish solid, mp 197.0–198.4 °C. (Found: C,
recorded on a Bruker 300-AC or a Bruker 400-ultrashield 52.11; H, 4.08; N, 15.87; S, 9.20. C15H14N4O4S requires C,
instrument. Chemical shifts (δ) are expressed in parts per 52.02; H, 4.07; N, 16.18; S, 9.26%); νmax (KBr)/cm−1 3276, 2118,
million relative to internal tetramethylsilane; coupling con- 2095, 1719; δH (300 MHz, DMSO-d6) 2.71 (1H, dd, J 13.4, 9.2,
1
stants (J) are in hertz. Mass spectra were run on a Bruker 1CH2Ar), 2.94 (1H, dd, J 13.4, 5.5, CH2Ar), 3.82–3.89 (1H, m,
2
2
Esquire 3000 spectrometer. Elemental analyses (C, H, N, S) CH), 7.11–7.21 (7H, m, ArH), 7.56 (2H, d, J 8.6, ArH), 8.34
were performed on a LECO CHNS-932 apparatus at the Micro- (1H, d, J 9.2, SO2NH), 12.78 (1H, bs, COOH); δC (75.4 MHz,
analyses Service of the University Complutense of Madrid; DMSO-d6) 37.8, 57.5, 119.4, 126.5, 128.2, 128.3, 129.2, 136.8,
unless otherwise stated, all reported values are within 0.4% 137.3, 143.3, 172.4. EM (ESI+) m/z 328.06 [M − H2O]+ 369.01
of the theoretical compositions. Thin-layer chromatography [M + Na]+.
(TLC) was run on Merck silica gel 60 F-254 plates. Unless
stated otherwise, the starting materials used were high-grade acid ((R)-4). Compound (R)-3 (2.14 g, 6.68 mmol) was sus-
commercial products. pended into anhydrous CH3CN (50 mL) under argon and
(2R)-2-{[(4-Azidophenyl)sulfonyl]amino}-3-phenylpropanoic
2-{[(4-Aminophenyl)sulfonyl]amino}-3-phenylpropanoic acid cooled to 0 °C in an ice bath. To this suspension was added
(3). A solution of 227 (2.2 g, 6.28 mmol) in EtOH (50 mL) and t-BuONO (1.19 mL, 10.02 mmol), followed by TMSN3 (1.05 mL,
10% Pd/C (220 mg) were introduced into a Parr shaker appar- 8.02 mmol) dropwise. The reaction mixture was stirred at 0 °C
atus, and maintained under a hydrogen pressure of 60 p.s.i. for 30 min, and at room temperature for 3 h. Then, it was
for 18 h at room temperature. Palladium was filtered off and evaporated to dryness, and the residue was purified by column
the solvent was removed. Then, it was evaporated to dryness, chromatography on silica gel (DCM–MeOH 2.5% MeOH) to
and the residue was purified by column chromatography on afford (R)-4 (2.16 g, 93%) as a yellowish solid, mp 127–128 °C.
silica gel (hexane–EtOAc 1 : 4) to afford 3 (1.57 g, 78%) as a
(2S)-2-{[(4-Azidophenyl)sulfonyl]amino}-3-phenylpropanoic
white solid, mp 205–206 °C (EtOH). (Found: C, 56.04; H, 5.00; acid ((S)-4). Compound (S)-3 (2.48 g, 7.73 mmol) was sus-
N, 8.82; S, 9.97. C15H16N2O4S requires C, 56.24; H, 5.03; pended in anhydrous CH3CN (50 mL) under argon and cooled
N, 8.74; S, 10.01%); νmax (KBr)/cm−1 3372, 3306, 3284, 1719; to 0 °C in an ice bath. To this suspension was added t-BuONO
1
2
δH (300 MHz, DMSO-d6) 2.68 (1H, dd, J 13.4, 7.9, CH2), 2.91 (1.38 mL, 11.60 mmol), followed by TMSN3 (1.22 mL,
(1H, dd, J 13.4, 6.1, 12CH2), 3.69–3.76 (1H, m, CH), 5.90 (2H, bs, 9.28 mmol) dropwise. The reaction mixture was stirred at 0 °C
NH2), 6.48 (2H, d, J 8.5, ArH), 7.09–7.12 (2H, m, ArH), for 30 min, and at room temperature for 3 h. Then, it was
7.17–7.27 (5H, m, ArH), 7.69 (1H, d, J 8.5, SO2NH), 12.64 (1H, evaporated to dryness, and the residue was purified by column
bs, COOH); δC (75.4 MHz, DMSO-d6) 37.9, 57.1, 112.4, 125.8, chromatography on silica gel (DCM–MeOH 2.5% MeOH) to
126.4, 128.1, 128.4, 129.2, 136.9, 152.4, 172.4. EM (ESI+) m/z afford (S)-4 (2.25 g, 84%) as a yellowish solid, mp 127–128 °C.
319.00 [M − H]+.
2-{[(4-Azidophenyl)sulfonyl]amino}-3-phenyl-N-(tetrahydro-
(2R)-2-{[(4-Aminophenyl)sulfonyl]amino}-3-phenylpropanoic 2H-pyran-2-yloxy)propanamide (5). To a solution of 4 (1.3 g,
acid ((R)-3). A solution of (R)-227 (2.42 g, 6.91 mmol) in EtOH 3.75 mmol) in DMF (30 mL) were added HOBt (1.11 g,
148 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
8.25 mmol), O-tetrahydro-2H-pyran-2-yl-hydroxylamine (0.88 g, 0.25 M solution in water) under argon. The mixture was stirred
7.50 mmol), EDCI (1.72 g, 9 mmol) and NMM (1.5 mL, vigorously overnight, and then diluted with water (20 mL) and
15 mmol). The reaction mixture was stirred overnight at room extracted with AcOEt. The organic layer was washed succes-
temperature and then diluted with EtOAc (50 mL) and washed sively with saturated aqueous NH4Cl and brine. The extract
successively with a saturated aqueous solution of NH4Cl and was dried (MgSO4), filtered and evaporated to dryness, and the
brine. The organic layer was dried (MgSO4), and evaporated to residue was chromatographed on silica gel.
dryness, and the residue was purified by column chromato-
2-[({4-{4-[(3-Fluorophenyl)-1H-1,2,3-triazol-1-yl]phenyl}sulfo-
graphy on silica gel (hexane–AcOEt 7 : 3) to afford 5 (1.14 g, nylamino]-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)-propanamide
68%) as a yellow solid. This compound is present as a diaster- (6a). From 5 (100 mg, 0.224 mmol), 1-ethynyl-3-fluorobenzene
eoisomeric mixture (55 : 45), mp 142–144 °C. (Found: C, 53.81; (44 mg, 0.247 mmol), sodium ascorbate (448 μL, 0.448 mmol)
H, 5.14; N, 15.37; S, 7.18. C20H23N5O5S requires C, 53.92; H, and copper(II) sulfate pentahydrate (448 μL, 0.112 mmol) in
5.20; N, 15.72; S, 7.20%); νmax (KBr)/cm−1 3213, 2130, 2097, DMF (3 mL), 6a (84.8 mg, 67%) was produced as a light yellow
1673; δH (300 MHz, CDCl3) 1.45–1.65 (4H, m, CH2), 1.68–1.82 solid after chromatography purification (hexane–AcOEt 1 : 1 +
(2H, m, CH2), 2.87–3.05 (2H, m, CH2Ph), 3.54–3.58 (1H, m, 2% MeOH), mp 146–147 °C. (Found: C, 59.06; H, 5.08;
CHN), 3.81–3.92 (2H, m, OCH2), 4.72 (0.45H, m, O–CH–O, N, 12.27; S 5.70. C28H28FN5O5S requires C, 59.46; H, 4.99;
isomer b), 4.77 (0.55H, m, O–CH–O, isomer a), 5.47, (0.55H, d, N, 12.38; S, 5.67%); νmax (KBr)/cm−1 3203, 1665, 1620; δH
1
1
J 7.8, SO2NH, isomer a), 5.52 (0.45H, d, J 7.8, SO2NH, isomer (300 MHz, DMSO-d6) 1.43–1.59 (6H, m, 3CH2), 2.66–2.73
2
2
b), 6.96–7.02 (5H, m, ArH), 7.18–7.21 (2H, m, ArH), 7.59 (2H, (1H, m, 1CH2Ph), 2.79–2.89 (1H, m, 1CH2Ph), 3.38–3.49 (1H,
2
2
d, J 8.4, ArH), 9.05 (1H, s, CONH, isomer a), 9.17 (1H, s, m, CHN), 3.76–3.85 (1H, m, OCH2, isomer a), 3.93–3.98 (1H,
CONH, isomer b); δC (75.4 MHz, CDCl3): 18.4, 18.6, 24.9, 27.9, m, OCH2, isomer b), 4.39 (0.5H, s, O–CH–O, isomer a), 4.57
38.6, 39.0, 56.6, 62.5, 62.7, 102.5, 119.5, 127.4, 128.9, 129.0, (0.5H, s, O–CH–O, isomer b), 7.11–7.29 (6H, m, ArH),
129.3, 134.9, 135.2, 145.0, 167.5. EM (ESI+) m/z 468.00 [M + Na]+. 7.55–7.62 (1H, m, ArH), 7.76–7.84 (4H, m, ArH), 8.02 (2H, dd,
(2R)-2-{[(4-Azidophenyl)sulfonyl]amino}-3-phenyl-N-(tetrahydro- J 8.7, 1.4, ArH), 8.54 (1H, bs, SO2NH), 9.51 (1H, s, triazole),
2H-pyran-2-yloxy)propanamide ((R)-5). To a solution of (R)-4 11.25 (0.5H, bs, CONH, isomer a) 11.32 (0.5H, bs, CONH,
(0.5 g, 1.44 mmol) in DMF (5 mL) were added HOBt (234 mg, isomer b); δC (75.4 MHz, DMSO-d6): 18.2, 24.5, 27.7, 38.5, 55.2,
2
2
1.73
mmol),
O-tetrahydro-2H-pyran-2-yl-hydroxylamine 61.3 (61.4 b), 101.0, 112.0 (d, JCF 22.5), 115.17 (d, JCF 21.0),
2
(338 mg, 2.89 mmol), EDCI (387 mg, 2.02 mmol) and NMM 119.9, 120.9 (d, JCF 74.2), 126.4, 128.0, 128.1, 129.2 (129.3 b),
(0.48 mL, 4.33 mmol). The reaction mixture was stirred over- 131.3 (d, JCF 9.0), 132.31 (d, JCF 9.0), 136.5, 136.8, 138.6,
night at room temperature and then diluted with EtOAc 140.9, 146.4, 162.6 (d, JCF 241.5), 166.6 (166.7 b). EM (ESI+):
3
3
1
(50 mL) and washed successively with a saturated aqueous m/z 588.26 [M + Na]+.
solution of NH4Cl and brine. The organic layer was dried
2-{[(4-{4-[(Biphenyl-4-yl)]-1H-1,2,3-triazol-1-yl}phenyl)sulfonyl]-
(MgSO4), and evaporated to dryness, and the residue was puri- amino}-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propanamide
fied by column chromatography on silica gel (hexane–AcOEt (6b). From 5 (100 mg, 0.224 mmol), 4-ethynylbiphenyl (44 mg,
3 : 2) to afford (R)-5 (594 mg, 92%) as a yellow solid. This com- 0.247 mmol), sodium ascorbate (448 μL, 0.448 mmol) and
pound is present as a diastereoisomeric mixture (55 : 45), mp copper(II) sulfate pentahydrate (448 μL, 0.112 mmol) in DMF
137–138 °C.
(3 mL), 6b (89 mg, 64%) was produced as a yellow solid after
(2S)-2-{[(4-Azidophenyl)sulfonyl]amino}-3-phenyl-N-(tetrahydro- chromatography purification (DCM–MeOH 0.6% MeOH), mp
2H-pyran-2-yloxy)propanamide ((S)-5). To a solution of (S)-4 189–191 °C. (Found: C, 64.74; H, 5.45; N, 11.13; S, 5.13.
(0.5 g, 1.44 mmol) in DMF (5 mL) were added HOBt (234 mg, C34H33N5O5S·0.5H2O requires C, 64.54; H, 5.42; N, 11.07; S,
1.73
mmol),
O-tetrahydro-2H-pyran-2-yl-hydroxylamine 5.07%); νmax (KBr)/cm−1 3284, 1668; δH (300 MHz, CDCl3)
(338 mg, 2.89 mmol), EDCI (387 mg, 2.02 mmol) and NMM 1.44–1.56 (6H, m, 3CH2), 2.67–2.74 (1H, m, 12CH2Ph), 2.80–2.86
(0.48 mL, 4.33 mmol). The reaction mixture was stirred over- (1H, m, 1CH2Ph), 3.39–3.49 (1H, m, CHN), 3.75–3.85 (1H,
2
night at room temperature and then diluted with EtOAc m, OCH2, isomer a), 3.86–3.97 (1H, m, OCH2, isomer b),
(50 mL) and washed successively with a saturated aqueous 4.38 (0.5H, s, O–CH–O, isomer a), 4.57 (0.5H, s, O–CH–O,
solution of NH4Cl and brine. The organic layer was dried isomer b), 7.11–7.22 (5H, m, ArH), 7.37–7.42 (1H, m, ArH),
(MgSO4), evaporated to dryness, and the residue was purified 7.48–7.53 (2H, m, ArH), 7.76 (2H, d, J 7.3, ArH), 7.80–7.86
by column chromatography on silica gel (hexane–AcOEt 3 : 2) (4H, m, ArH), 8.04–8.09 (4H, m, ArH), 8.53 (1H, m, SO2NH),
to afford (S)-5 (589 mg, 92%) as a yellow solid. This compound 9.5 (1H, s, triazole), 11.25 (0.5H, s, CONH, isomer b), 11.33
is present as a diastereoisomeric mixture (55 : 45), mp (0.5H, s, CONH, isomer a); δC (75.4 MHz, CDCl3): 18.1,
137–138 °C.
24.4, 27.6, 38.6, 55.1, 61.3, 101.0, 119.6, 119.7, 125.8, 126.3,
126.5, 127.21, 127.6, 127.9, 128.1, 128.9, 129.1, 136.5, 136.7,
138.6, 139.3, 139.9, 140.8, 147.2, 166.5. EM (ESI+) m/z 646.26
Preparation of triazoles: general procedure 1
To a suspension of azide 5 (1 equiv.) and the corresponding [M + Na]+.
alkyne (1–1.5 equiv.) in t-BuOH–H2O (1 : 1) or DMF were added
(2R)-2-{[(4-{4-[(Biphenyl-4-yl)]-1H-1,2,3-triazol-1-yl}phenyl)-
sodium ascorbate (2 equiv. of freshly prepared 1 M solution in sulfonyl]amino}-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propa-
water) and copper(II) sulfate pentahydrate (0.5 equiv. of a namide ((R)-6b). From (R)-5 (150 mg, 0.337 mmol), 4-ethynyl-
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 149

View Article Online
Paper
Organic & Biomolecular Chemistry
biphenyl (90 mg, 0.505 mmol), sodium ascorbate (673 μL,
3-Phenyl-2-[({4-[4-({[(phenylsulfonyl)amino]carbonyl}amino-
0.673 mmol) and copper(II) sulfate pentahydrate (673 μL, methyl)-1H-1,2,3-triazol-1-yl]-phenyl}sulfonyl)amino]-N-(tetra-
0.168 mmol) in t-BuOH–H2O (1 : 1, 5 mL), (R)-6b (68 mg, 32%) hydro-2H-pyran-2-yloxy)propanamide (6d). From 5 (100 mg,
was produced as a white solid after chromatography purifi- 0.224 mmol), N-[(prop-2-yn-1-yl-amino)carbonyl)]benzenesul-
cation (DCM–MeOH 0.6% MeOH), mp 199–200 °C (hexane– fonamide23 (58.5 mg, 0.247 mmol), sodium ascorbate (448 μL,
EtOAc).
0.448 mmol) and copper(II) sulfate pentahydrate (448 μL,
(2S)-2-{[(4-{4-[(Biphenyl-4-yl)]-1H-1,2,3-triazol-1-yl}phenyl)- 0.112 mmol) in DMF (3 mL), 6d (87.6 mg, 60%) was produced
sulfonyl]amino}-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propa- as a beige solid after chromatography purification (DCM–
namide ((S)-6b). From (S)-5 (150 mg, 0.337 mmol), 4-ethynyl- MeOH, 5% MeOH), mp 165–167 °C. (Found: C, 52.64; H, 4.96;
biphenyl (90 mg, 0.505 mmol), sodium ascorbate (673 μL, N, 14.10; S, 9.15. C30H33N7O8S2 requires: C, 52.70; H, 4.86;
0.673 mmol) and copper(II) sulfate pentahydrate (673 μL, N, 14.34; S, 9.38) νmax (KBr)/cm−1 3343, 3284, 1694, 1675 cm−1
.
0.168 mmol) in t-BuOH–H2O (1 : 1, 5 mL), (S)-6b (105 mg, δH (300 MHz, DMSO-d6) 1.35–1.58 (6H, m, 3CH2), 2.64–2.73
50%) was produced as a white solid after chromatography puri- (1H, m, 1CH2Ph), 2.78–2.84 (1H, m, 1CH2Ph), 3.37–3.45 (2H,
2
2
fication (DCM–MeOH 0.6% MeOH), mp 199–200 °C (hexane– m, OCH2), 3.75–3.80 (0.5H, m, CHN, isomer a), 3.89–3.94
EtOAc). (0.5H, m, CHN, isomer b), 4.31 (2H, s, NHCH2), 4.33 (0.5H, s,
2-{[(4-{4-[(4-Dimethylamino)phenyl]-1H-[1,2,3]-triazol-1-yl}- O–CH–O, isomer a), 4.55 (0.5H, s, O–CH–O, isomer b),
phenyl)sulfonyl]amino}-3-phenyl-N-(tetrahydro-2H-pyran- 7.09–7.2 (7H, m, ArH + NHCONH), 7.54–7.63 (3H, m, Ar),
2-yloxy)propanamide (6c). From 5 (100 mg, 0.224 mmol), 7.73–7.76 (2H, m, ArH), 7.89–7.93 (4H, m, ArH), 8.47–8.54 (1H,
4-ethynyl-N,N-dimethylaniline (36 mg, 0.248 mmol), sodium m, SO2NH), 8.61 (1H, s, triazole), 11.23 (0.5H, s, CONH,
ascorbate (448 μL, 0.448 mmol) and copper(II) sulfate penta- isomer b), 11.31 (0.5H, s, CONH, isomer a); δC (75.4 MHz,
hydrate (448 μL, 0.112 mmol) in DMF (3 mL), 6c (71.6 mg, 54%) DMSO-d6) 18.0, 24.4, 27.5, 34.6, 37.2, 55.1 (55.2 b), 61.3, 100.9
was produced as a yellow solid after chromatography purifi- (101.1 b), 119.8, 120.9, 126.2, 127.08, 127.9 (127.9 b), 128.8,
cation (DCM–MeOH 0.75% MeOH), mp 192–194 °C. (Found: 129.1 (129.1 b), 133.0, 136.4, 136.7, 138.5, 140.2, 140.7, 145.9,
C, 59.92; H, 5.91; N, 13.96; S, 5.27. C30H34N6O5S·0.5H2O 151.4, 166.6. MS (ESI−) m/z 682.30 [M − H]−.
requires: C, 60.08; H, 5.88; N, 14.01; S, 5.35%); νmax (KBr)/cm−1
3276, 1668, 1616. δH (300 MHz, DMSO-d6) 1.43–1.58 (6H, m, fonyl)amino]-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propana-
2-[({4-[4-(4-Methoxyphenyl)-1H-1,2,3-triazol-1-yl]phenyl}sul-
1
2
1
2
3CH2), 2.65–2.73 (1H, m, CH2Ph), 2.79–2.85 (1H, m, CH2Ph), mide (6e). From 5 (100 mg, 0.224 mmol), 4-ethynylanisole
2.96 (6H, s, 2CH3), 3.38–3.49 (1H, m, CH), 3.75–3.85 (1H, (33 mg, 0.25 mmol), sodium ascorbate (448 μL, 0.448 mmol)
m, OCH2, isomer a), 3.85–3.95 (1H, m, OCH2, isomer b), and copper(II) sulfate pentahydrate (448 μL, 0.112 mmol) in
4.36 (0.5H, s, O–CH–O, isomer a), 4.56 (0.5H, s, O–CH–O, DMF (3 mL), 6e (98.8 mg, 76%) was produced as a yellow solid
isomer b), 6.84 (2H, d, J 8.9, ArH), 7.1–7.2 (5H, m, Ar), after chromatography purification (DCM–MeOH, 5% MeOH),
7.76–7.81 (4H, m, Ar), 8.02 (2H, d, J 8.6, ArH), 8.53 (1H, mp 151–153 °C. (Found: C, 59.94; H, 5.46; N, 12.04; S, 5.54;
bs, SO2NH), 9.2 (1H, s, triazole), 11.23 (0.5H, s, CONH, isomer C29H31N5O6S requires: C, 60.3; H, 5.41; N, 12.12; S, 5.55%);
b), 11.32 (0.5H, s, CONH, isomer a); δC (75.4 MHz, DMSO-d6): νmax (KBr)/cm−1 3202, 1668, 1620. δH (300 MHz, DMSO-d6)
18.1, 24.4, 27.6, 37.2, 39.8, 55.1, 61.3, 100.9, 112.2, 1.43–1.58 (6H, m, 3CH2), 2.66–2.73 (1H, m, 12CH2Ph), 2.79–2.85
117.3, 117.4, 119.4, 126.2, 127.9, 128.0, 129.1, 136.5, (1H, m, 1CH2Ph), 3.35–3.48 (1H, m, CH), 3.76–3.85 (1H, m,
2
136.7, 138.7, 140.3, 148.2, 150.2, 166.5. EM (ESI+) m/z 613.30 OCH2, isomer a), 3.82 (3H, s, OCH3), 3.87–3.95 (1H, m, OCH2,
[M + Na]+.
isomer b), 4.37 (0.5H, s, O–CH–O, isomer a), 4.56 (0.5H, s,
(2R)-2-{[(4-{4-[(4-Dimethylamino)phenyl]-1H-[1,2,3]-triazol-1- O–CH–O, isomer b), 6.84 (2H, d, J 8.9, ArH), 7.1–7.2 (7H, m,
yl}phenyl)sulfonyl]amino}-3-phenyl-N-(tetrahydro-2H-pyran-2- ArH), 7.78–7.81 (2H, dd, J 8.7, 2.3, ArH), 7.89 (2H, d, J 8.7,
yloxy)propanamide ((R)-6c). From (R)-5 (150 mg, 0.337 mmol), ArH), 8.00–8.04 (2H, dd, J 8.7, 1.5, ArH), 8.44 (1H, bs, SO2NH),
4-ethynyl-N,N-dimethylaniline (73 mg, 0.505 mmol), sodium 9.32 (1H, s, triazole), 11.24 (0.5H, s, CONH, isomer b), 11.32
ascorbate (673 μL, 0.673 mmol) and copper(II) sulfate penta- (0.5H, s, CONH, isomer a); δC (75.4 MHz, DMSO-d6): 18.1, 24.4,
hydrate (673 μL, 0.168 mmol) in t-BuOH–H2O (1 : 1, 5 mL), 27.5, 38.5, 55.1, 55.2, 61.3, 100.9 (101.1 b), 114.4, 119.6,
(R)-6c (130 mg, 65%) was produced as a yellow solid after 122.3, 126.3, 126.7, 127.9, 128.0, 129.1 (129.2 b), 136.5, 136.7,
chromatography purification (DCM–MeOH 0.75% MeOH), mp 138.7, 140.6, 147.5, 159.3, 166.5 (166.6 b). MS (ESI+): m/z
203–204 °C (hexane–EtOAc).
600.27 [M + Na]+.
(2S)-2-{[(4-{4-[(4-Dimethylamino)phenyl]-1H-[1,2,3]-triazol-1-
2-[({4-[4-(4-Phenoxyphenyl)-1H-1,2,3-triazol-1-yl]phenyl}sul-
yl}phenyl)sulfonyl]amino}-3-phenyl-N-(tetrahydro-2H-pyran-2- fonyl)amino]-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propana-
yloxy)propanamide ((S)-6c). From (S)-5 (150 mg, 0.337 mmol), mide (6f). From (100 mg, 0.224 mmol), 1-ethynyl-4-
5
4-ethynyl-N,N-dimethylaniline (73 mg, 0.505 mmol), sodium phenoxybenzene (48 mg, 0.247 mmol), sodium ascorbate
ascorbate (673 μL, 0.673 mmol) and copper(II) sulfate penta- (448 μL, 0.448 mmol) and copper(II) sulfate pentahydrate
hydrate (673 μL, 0.168 mmol) in t-BuOH–H2O (1 : 1, 5 mL), (S)-6c (448 μL, 0.112 mmol) in DMF (3 mL), 6f (115 mg, 80%) was
(130 mg, 65%) was produced as a yellow solid after chromato- produced as a pale yellow solid after chromatography purifi-
graphy purification (DCM–MeOH 0.75% MeOH), mp 203–204 °C cation (hexane–AcOEt 1 : 1 + 2% MeOH), mp 189–190 °C.
(hexane–EtOAc).
(Found: C, 63.70; H, 5.26; N, 10.87; S, 4.95; C34H33N5O6S
150 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
requires: C, 63.83; H, 5.20; N, 10.95; S, 5.01%); νmax (KBr)/cm−1 Cleavage of the tetrahydropyrane protecting group: general
3166, 1657. δH (300 MHz, DMSO-d6): 1.43–1.58 (6H, m, 3CH2), procedure 2
2.66–2.73 (1H, m, 1CH2Ph), 2.79–2.86 (1H, m, 1CH2Ph), To a suspension of the corresponding tetrahydro-2H-pyranyl
2
2
3.42–3.49 (1H, m, CH), 3.76–3.85 (1H, m, OCH2, isomer a), derivative in DCM (5 mL) were added 4 M HCl in dioxane
3.93–3.98 (1H, m, OCH2, isomer b), 4.38 (0.5H, s, O–CH–O, (4 equivalents) and MeOH (0.1 mL). After stirring at room
isomer a), 4.57 (0.5H, s, O–CH–O, isomer b), 7.08–7.21 (10H, temperature for 1 h the reaction mixture was concentrated
m, ArH), 7.41–7.46 (2H, m, ArH), 7.78–7.82 (2H, dd, J 8.6, 2,1, under vacuum and the obtained solid was washed with DCM–
ArH), 7.89 (2H, d, J 8.6, ArH), 8.03 (2H, d, J 7.4, ArH), 8.5 (1H, hexane 1 : 1.
bs, SO2NH), 9.39 (1H, s, triazole), 11.32 (1H, bs, CONH);
2-[({4-[4-(3-Fluorophenyl)-1H-1,2,3-triazol-1-yl]phenyl}sulfo-
δC (75.4 MHz, DMSO-d6) 18.2, 24.5, 27.6, 38.5, 55.2, 61.4, nyl)amino]-N-hydroxy-3-phenylpropanamide (1a). From 6a
101.1, 118.93, (118.98 b), 119.2, 119.7, 123.7, 125.1, 126.4, (111 mg, 0.178 mmol), MeOH (0.18 mL) and 4 M HCl–dioxane
127.2, 128.0, 128.15, 129.2 (129.3 b), 130.1, 136.5, 136.8, 138.7, (0.18 mL, 0.72 mmol), 1a was produced as a light beige solid
140.7, 147.1, 156.3, 156.9, 166.5 (166.7 b). MS (ESI+): m/z (73.2 mg, 76%), mp 210 °C (dec.). (Found: C, 56.67; H, 4.22;
662.26 [M + Na]+.
N, 14.35; S, 6.54. C23H20FN5O4S requires: C, 57.37; H, 4.19;
(2R)-2-[({4-[4-(4-Phenoxyphenyl)-1H-1,2,3-triazol-1-yl]phenyl}- N, 14.54; S, 6.66; νmax (KBr)/cm−1 3313, 1675, 1620; δH
1
sulfonyl)amino]-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propana- (300 MHz, DMSO-d6) 2.68 (1H, dd, J 13.5, 9.1, CH2Ph), 2.83
mide ((R)-6f). From (R)-5 (150 mg, 0.337 mmol), 1-ethynyl- (1H, dd, J 13.5, 5.8, CH2Ph), 3.84–3.92 (1H, m, CH), 7.09–7.16
2
1
2
4-phenoxybenzene (98 mg, 0.505 mmol), sodium ascorbate (5H, m, ArH), 7.25 (1H, dt, J 8.5, 2.1, ArH), 7.54–7.61 (1H, m,
(673 μL, 0.673 mmol) and copper(II) sulfate pentahydrate ArH), 7.77 (2H, d, J 8.7, ArH), 7.83 (1H, d, J 7.7, ArH), 7.99 (2H,
(673 μL, 0.168 mmol) in t-BuOH–H2O (1 : 1, 5 mL), (R)-6f d, J 8.7, ArH), 8.43 (1H, d, J 8.9, SO2NH), 8.87 (1H, bs,
(170 mg, 79%) was produced as a white solid after chromato- CONHOH), 9.47 (1H, s, CH, triazole), 10.67 (1H, s, CONHOH);
2
graphy purification (DCM–MeOH 0.6% MeOH), mp 169–170 °C δC (75.4 MHz, DMSO-d6) 38.4, 55.5, 111.8–112.1 (d, JCF 22.5),
2
2
(hexane–EtOAc).
114.9–115.2 (d, JCF 21.0), 119.85, 120.8 (d, JCF 74.2), 126.2,
3
3
(2S)-2-[({4-[4-(4-Phenoxyphenyl)-1H-1,2,3-triazol-1-yl]phenyl}- 127.9, 129.1, 131.15 (d, JCF 9.0), 132.26 (d, JCF 9.0), 136.8,
sulfonyl)amino]-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)- 138.4, 141.0, 146.4, 162.5 (d, J 241.5, Ar–F), 166.6. MS (ESI):
propanamide ((S)-6f). From (S)-5 (150 mg, 0.337 mmol), m/z 504.20 [M + Na]+.
1-ethynyl-4-phenoxybenzene (98 mg, 0.505 mmol), sodium
2-[({4-[4-(Biphenyl-4-yl)-1H-1,2,3-triazol-1-yl]phenyl}sulfonyl)-
ascorbate (673 μL, 0.673 mmol) and copper(II) sulfate pentahy- amino]-N-hydroxy-3-phenyl-propanamide (1b). From 6b
drate (673 μL, 0.168 mmol) in t-BuOH–H2O (1 : 1, 5 mL), (S)-6f (83.8 mg, 0.147 mmol), MeOH (0.14 mL) and 4 M HCl–dioxane
(175 mg, 81%) was produced as a white solid after chro- (0.14 mL, 0.56 mmol), 1b was produced as a light yellow solid
matography purification (DCM–MeOH 0.6% MeOH), mp (54.0 mg, 75%), mp 182–183 °C (Found: C, 62.81; H, 4.72;
169–170 °C (hexane–EtOAc).
N, 12.63; S, 5.57. C29H25N5O4S·H2O requires: C, 62.46; H, 4.88;
2-[({4-[4-(4-Pentylphenyl)-1H-1,2,3-triazol-1-yl]phenyl}sulfo- N, 12.56; S, 5.75%). νmax (KBr)/cm−1 3557, 3284, 1683, 1668. δH
1
nyl)amino]-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propana- (300 MHz, DMSO-d6): 2.69 (1H, dd, J 13.5, 9.1, CH2Ar), 2.84
2
1
2
mide (6g). From
5
(100 mg, 0.224 mmol), 1-ethynyl- (1H, dd, J 13.5, 5.8, CH2Ar), 3.84–3.93 (1H, m, CH), 7.10–7.16
4-pentylbenzene (42.5 mg, 0.247 mmol), sodium ascorbate (5H, m, ArH), 7.39 (1H, t, J 7.3, ArH), 7.48–7.52 (2H, m, ArH),
(448 μL, 0.448 mmol) and copper(II) sulfate pentahydrate 7.75–7.86 (6H, m, ArH), 8.02 (2H, d, J 8.6, ArH), 8.07 (2H, d,
(448 μL, 0.112 mmol) in DMF (3 mL), 6g (107 mg, 77%) was J 8.1, ArH), 8.43 (1H, d, J 8.9, SO2NH), 8.86 (1H, bs, OH), 9.47
produced as a pale yellow solid after chromatography purifi- (s, 1H, CH, triazole), 10.68 (s, 1H, CONH); δC (75 MHz, DMSO-
cation (hexane–AcOEt 1 : 1 + 2% MeOH), mp 189–190 °C. d6) 38.4, 55.5, 119.6, 119.7, 125.8, 126.2, 126.5, 127.2, 127.5,
(Found: C, 63.72; H, 6.43; N, 11.32; S, 5.17; C33H39N5O5S 127.9, 127.9, 128.9, 128.9, 129.1, 136.8, 138.5, 139.4, 139.9,
requires: C, 64.16; H, 6.36; N, 11.34; S, 5.19; νmax (KBr)/cm−1 140.8, 147.2, 166.6. MS (ESI+): m/z 562.27 [M + Na]+.
3291, 1690. δH (300 MHz, DMSO-d6) 0.87 (3H, t, J 6.8, CH3),
(2R)-2-[({4-[4-(Biphenyl-4-yl)-1H-1,2,3-triazol-1-yl]phenyl}sul-
1.30–1.63 (12H, m, 6CH2), 2.62–2.73 (3H, t, J 7.6, CH2Ar + m, fonyl)amino]-N-hydroxy-3-phenyl-propanamide ((R)-1b). From
12CH2Ph), 2.79–2.89 (1H, m, 1CH2Ph), 3.42–3.49 (1H, m, CH), (R)-6b (48 mg, 0.077 mmol), MeOH (1 mL) and 4 M HCl–
2
3.78–3.85 (1H, m, OCH2, isomer a), 3.92–3.99 (1H, m, OCH2, dioxane (1 mL, 4 mmol), (R)-1b was produced as a white solid
isomer b), 4.37 (0.5H, s, O–CH–O, isomer a), 4.57 (0.5H, s, (34.1 mg, 82%), mp 240 °C (dec.) (EtOH) (Found: C, 63.91;
O–CH–O, isomer b), 7.01–7.21 (5H, m, ArH), 7.34 (2H, d, J 8.1, H, 4.70; N, 12.93; S, 5.99. C29H25N5O4S·H2O requires: C, 64.01;
ArH), 7.80 (2H, dd, J 8.7, 2.1, ArH), 7.87 (2H, d, J 8.0, ArH), H, 4.72; N, 12.87; S, 5.89%). [α]2D5 − 8.3 (c 0.0012 g cm−3 in
8.03 (2H, dd, J 8.6, 1.6, ArH), 8.52 (1H, bs, SO2NH), 9.38 (1H, s, DMSO).
triazole), 11.24 (0.5H, bs, CONH isomer a), 11.32 (0.5H, bs,
(2S)-2-[({4-[4-(Biphenyl-4-yl)-1H-1,2,3-triazol-1-yl]phenyl}sul-
CONH, isomer b); δC (75.4 MHz, DMSO-d6) 13.9, 18.2, 21.9, fonyl)amino]-N-hydroxy-3-phenyl-propanamide ((S)-1b). From
24.5, 27.7, 30.5, 30.8, 34.8, 38.5, 55.3, 61.4, 101.0, 119.1 (119.7 (S)-6b (78 mg, 0.125 mmol), MeOH (1 mL) and 4 M HCl–
b), 125.3, 126.4, 127.4, 128.04, 128.1, 128.9, 129.2 (129.3 b), dioxane (3 mL, 12 mmol), (S)-1b was produced as a white solid
136.5, 136.8, 138.7, 140.79, 142.7, 147.7, 166.5 (166.7 b). MS (58 mg, 86%), mp 240 °C (dec.) (EtOH) (Found: C, 64.32;
(ESI+): m/z 640.33 [M + Na]+.
H, 4.68; N, 12.89; S, 5.92. C29H25N5O4S requires: C, 64.55;
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 151

View Article Online
Paper
Organic & Biomolecular Chemistry
H, 4.67; N, 12.98; S, 5.94%). [α]2D5 + 7.9 (c 0.007 g cm−3 in N, 13.96; S, 6.35. C24H23N5O5S·1/3H2O requires: C, 57.70; H,
DMSO).
4.78; N, 14.02; S, 6.42%); νmax (KBr)/cm−1 3571, 3298, 1668,
2-{[(4-{[4-(4-Dimethylamino)phenyl]-1H-1,2,3-triazol-1-yl}- 1635. δH (300 MHz, DMSO-d6) 2.67(1H, dd, J 13.5, 9.0,
1
phenyl)sulfonyl]amino}-N-hydroxy-3-phenylpropanamide hydro- 1CH2Ph), 2.83 (1H, dd, J 13.5, 5,6 CH2Ph), 3.82 (3H, s, OCH3),
2
2
chloride (1c). From 6c (79.8 mg, 0.135 mmol), MeOH 3.85–3.91 (1H, m, CH), 7.07–7.16 (8H, m, ArH), 7.75 (2H, d,
(0.14 mL) and 4 M HCl–dioxane (0.14 mL, 0.56 mmol), 1c was J 8.7, ArH), 7.89 (2H, d, J 8.7, ArH), 7.98 (2H, d, J 8.7, ArH),
produced as a light orange solid (62.9 mg, 92%), mp 223 °C 8.42 (1H, d, J 8.9, SO2NH), 9.28 (s, 1H, CH, triazole), 10.67 (s,
(dec.) (Found: C, 54.71; H, 4.97; N, 15.40; S, 5.83; 1H, CONHOH); δC (75.4 MHz, DMSO-d6) 38.4, 55.2, 55.6, 114.4,
C25H26N6O4S·HCl·1/3H2O requires: C, 54.69; H, 5.08; N, 15.31; 118.6, 119.7, 122.5, 126.3, 126.8, 127.9, 128.0, 129.1, 136.8,
S, 5.84%); νmax (KBr)/cm−1 3431, 3188, 2428, 1679. δH 138.7, 140.8, 147.5, 159.4, 166.7. MS (ESI+) m/z 516.22 [M + Na]+.
1
(300 MHz, DMSO-d6) 2.68 (1H, dd, J 13.5, 9.1, CH2Ph), 2.83
N-Hydroxy-2-{[(4-[4-(4-phenoxyphenyl)-1H-1,2,3-triazol-1-yl]-
2
1
(1H, dd, J 13.5, 5.8, CH2Ph), 3.07 (6H, s, 2CH3) 3.84–3.92 (1H, phenyl)sulfonyl]amino}-3-phenylpropanamide (1f). From 6f
2
m, CH), 7.09–7.16 (5H, m, ArH), 7.42 (1H, bs, ArH), 7.75 (2H, (94 mg, 0.147 mmol), MeOH (0.15 mL) and 4 M HCl–dioxane
d, J 8.6, ArH), 7.95–8.01 (4H, m, ArH), 8.42 (1H, d, J 8.9, (0.15 mL, 0.60 mmol), 1f was produced as a pale yellow solid
SO2NH), 9.38 (1H, s, CH, triazole), 10.72 (1H, s, CONH); (64 mg, 78%), mp 229 °C (dec.) (Found: C, 61.59; H, 4.54;
δC (75.4 MHz, DMSO-d6) 38.4, 42.6, 55.5, 116.9, 118.9, 119.6, N, 12.32; S, 5.66; C29H25N5O5S·1/2H2O requires: C, 61.69; H,
126.2, 126.4, 127.9, 127.9, 129.1, 136.8, 138.5, 140.7, 147.1, 4.64; N, 12.40; S, 5.68%); νmax (KBr)/cm−1 3564, 3306, 1675. δH
166.6. MS (ESI−): m/z 505.19 [M − H]−.
(300 MHz, DMSO-d6) 2.67 (1H, dd, J 13.6, 9.0, CH2Ph), 2.82
1
2
1
(2R)-2-{[(4-{[4-(4-Dimethylamino)phenyl]-1H-1,2,3-triazol-1- (1H, dd, J 13.6, 5.8, CH2Ph), 3.83–3.91 (1H, m, CH), 7.08–7.21
2
yl}phenyl)sulfonyl]amino}-N-hydroxy-3-phenylpropanamide (10H, m, ArH), 7.41–7.46 (2H, m, ArH), 7.76 (2H, d, J 8.7, ArH),
hydrochloride ((R)-1c). From (R)-6c (74 mg, 0.125 mmol), 7.96–8.01 (4H, m, ArH), 8.42 (1H, d, J 8.9, SO2NH), 8.85 (1H, s,
MeOH (1 mL) and 4 M HCl–dioxane (3 mL, 12 mmol), (R)-1c CONHOH), 9.35 (s, 1H, CH, triazole), 10.66 (s, 1H, CONHOH);
was produced as a yellow solid (53.6 mg, 79%), mp 210 °C δC (75.4 MHz, DMSO-d6) 38.4, 55.5, 118.8, 118.9, 119.1, 119.7,
(dec.) (EtOH) (Found: C, 58.66; H, 5.20; N, 16.39; S, 6.26; 123.6, 125.1, 126.2, 127.1, 127.9, 127.9, 129.1, 130.0, 136.8,
C25H26N6O4S·1/3H2O requires: C, 58.58; H, 5.24; N, 16.40; 138.5, 140.8, 147.0, 156.2, 156.8, 166.6. MS (ESI−) m/z 554.27
S, 6.26%). [α]D25 – 0.81 (c 0.005 g cm−3 in DMSO).
[M − H]−.
(2S)-2-{[(4-{[4-(4-Dimethylamino)phenyl]-1H-1,2,3-triazol-1-
(2R)-N-Hydroxy-2-{[(4-[4-(4-phenoxyphenyl)-1H-1,2,3-triazol-
yl}phenyl)sulfonyl]amino}-N-hydroxy-3-phenylpropanamide 1-yl]phenyl)sulfonyl]amino}-3-phenylpropanamide ((R)-1f).
hydrochloride ((S)-1c). From (S)-6c (80 mg, 0.135 mmol), From (R)-6f (130 mg, 0.203 mmol), MeOH (1 mL) and 4 M
MeOH (1 mL) and 4 M HCl–dioxane (3 mL, 12 mmol), (S)-1c HCl–dioxane (3 mL, 12 mmol), (R)-1f was produced as a white
was produced as a yellow solid (61.4 mg, 83%), mp 210 °C solid (87.5 mg, 78%), mp 199–200 °C (EtOH). (Found: C, 62.59;
(dec.) (EtOH) (Found: C, 58.11; H, 5.11; N, 16.24; S, 6.18; H, 4.52; N, 12.52; S, 5.68; C29H25N5O5S requires: C, 62.69; H,
C25H26N6O4S·1/2H2O requires: C, 58.24; H, 5.28; N, 16.30; 4.54; N, 12.60; S, 5.77%). [α]2D5 – 2.06 (c 0.004 g cm−3 in DMSO).
S, 6.22%). [α]D25 + 0.99 (c 0.006 g cm−3 in DMSO).
(2S)-N-Hydroxy-2-{[(4-[4-(4-phenoxyphenyl)-1H-1,2,3-triazol-
N-Hydroxy-3-phenyl-2-{[(4-{4-[({[(phenylsulfonyl)amino]car- 1-yl]phenyl)sulfonyl]amino}-3-phenylpropanamide ((S)-1f).
bonyl}amino)methyl]-1H-1,2,3-triazol-1-yl}phenyl)sulfonyl]- From (S)-6f (125 mg, 0.195 mmol), MeOH (1 mL) and 4 M
amino}propanamide (1d). From 6d (117 mg, 0.17 mmol), HCl–dioxane (3 mL, 12 mmol), (S)-1f was produced as a white
MeOH (0.17 mL) and 4 M HCl–dioxane (0.17 mL, 0.68 mmol), solid (100.9 mg, 93%), mp 199–200 °C (EtOH). (Found: C,
1d was produced as a white solid (93 mg, 90%), mp 62.56; H, 4.51; N, 12.63; S, 5.75; C29H25N5O5S requires: C,
179–180 °C (Found: C, 49.53; H, 4.25; N, 16.08; S, 10.52. 62.69; H, 4.54; N, 12.60; S, 5.77%). [α]2D5 + 1.97 (c 0.010 g cm−3
C25H25N7O7S2·1/3H2O requires: C, 49.58; H, 4.27; N, 16.19; S, in DMSO).
10.59%); νmax (KBr)/cm−1 3579, 1690, 1642. δH (300 MHz,
N-Hydroxy-2-[({4-[4-(4-pentylphenyl)-1H-1,2,3-triazol-1-yl]-
DMSO-d6) 2.66 (1H, dd, J 13.6, 9.1, 1CH2Ph), 2.81 (1H, dd, phenyl}sulfonyl)amino]-3-phenylpropanamide (1g). From 6g
2
1
J 13.6, 5,9, CH2Ph), 3.81–3.89 (1H, m, CH), 4.33 (2H, d, J 5.5, (83.8 mg, 0.147 mmol), MeOH (0.15 mL) and 4 M HCl–dioxane
2
CH2NHCO), 7.04–7.16 (7H, m, NHCONH + ArH), 7.56–7.72 (0.15 mL, 0.60 mmol), 1g was produced as a yellow solid
(5H, m, ArH), 7.88–7.93 (4H, m, ArH), 8.41 (1H, d, J 8.9, (54 mg, 75%), mp 196 °C (dec.) (Found: C, 68.11; H, 6.53; N,
SO2NH), 8.59 (1H, s, CH, triazole), 10.65 (1H, s, CONHOH), 14.12; S, 6.47; C28H31N5O4S requires: C, 63.02; H, 5.86; N,
10.79 (1H, s, CONHOH); δC (75.4 MHz, DMSO-d6) 34.6, 38.3, 13.12; S, 6.01%); νmax (KBr)/cm−1 3549, 3291, 2450, 1664, 1635.
55.5, 119.8, 121.0, 126.20, 127.1, 127.8, 127.9, 128.9, 129.0, δH (300 MHz, DMSO-d6) 0.87 (3H, t, J 6.8, CH3), 1.29–1.32 (4H,
133.1, 136.7, 138.4, 140.0, 140.7, 145.8, 151.3, 166.6. MS (ESI−) m, 2CH2), 1.59–1.63 (2H, m, CH2), 2.60–2.71 (3H, t, J 7.6,
m/z 598.09 [M − H]−.
ArCH2CH2 + m, 1CH2 Ph), 2.79–2.86 (1H, dd, J 13.66, 5.8,
2
N-Hydroxy-2-[({4-[4-(4-methoxyphenyl)-1H-1,2,3-triazol-1-yl]- 1CH2Ar), 3.84–3.92 (1H, m, CH), 7.09–7.16 (5H, m, ArH), 7.33
2
phenyl}sulfonyl)amino]-3-phenylpropanamide (1e). From 6e (2H, d, J 8.1, ArH), 7.76 (2H, d, J 8.6, ArH), 7.87 (2H, d, J 8.0,
(112 mg, 0.194 mmol), MeOH (0.20 mL) and 4 M HCl–dioxane ArH), 8.00 (2H, d, J 8.7, ArH), 8.42 (1H, d, J 8.9, SO2NH), 9.35
(0.20 mL, 0.80 mmol), 1e was produced as a yellow solid (s, 1H, CH, triazole), 10.68 (s, 1H, CONHOH); δC (75.4 MHz,
(93 mg, 90%), mp 160 °C (dec.) (Found: C, 57.49; H, 4.70; DMSO-d6) 13.8, 21.9, 30.4, 30.8, 34.8, 38.4, 55.6, 119.2, 119.7,
152 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
125.4, 126.3, 127.4, 127.9, 128.0, 128.9, 129.1, 136.8, 138.6, was purified by column chromatography on silica gel (hexane–
140.8, 142.7, 147.7, 166.7. MS (ESI+) m/z 556.31 [M + Na]+.
AcOEt 2 : 8, 1 : 9) to give 10 as a white solid (0.165 g, 83%), mp
Methyl 2-{[(4-iodophenyl)sulfonyl]amino}-3-phenylpropano- 136–137 °C. νmax (KBr)/cm−1 3335, 3261, 2108, 1705, 1590. δH
1
2
ate (8). To a stirred mixture of the L-alanine methyl ester (1 g, (300 MHz, CDCl3) 2.98 (1H, dd, J 13.9, 7.3, CH2Ar), 3.15 (1H,
4.63 mmol) and NMM (1.3 mL, 11.6 mmol) in CH2Cl2 (5 mL) dd, J 13.9, 4.8, 12CH2Ar), 3.26 (1H, s, ArCCH), 4.19–4.27 (1H, m,
was slowly added a solution of 4-iodobenzenesulfonyl chloride CH), 5.28 (1H, d, J 8.3, SO2NH), 7.08–7.09 (2H, m, ArH),
(1.54 g, 5.1 mmol) in CH2Cl2 (5 mL) under a N2 atmosphere, 7.24–7.27 (3H, m, ArH), 7.48 (2H, d, J 8.3, ArH), 7.67 (2H, d,
and the reaction mixture was stirred for 30 min at 0 °C and J 8.3, ArH); δC (75.4 MHz, CDCl3) 38.7, 56.5, 80.8, 81.9, 126.8,
24 h at RT. The solvent was removed under reduced pressure, 126.9, 127.4, 128.7, 129.3, 132.5, 134.5, 139.5, 176.0. MS (ESI+)
the residue was dissolved in ethyl acetate, and the solution m/z 352.04 [M + Na]+.
was washed with HCl aqueous solution and brine. The extracts
were dried over anhydrous MgSO4, filtered, and evaporated. 2H-pyran-2-yloxy)propanamide (11). To
2-{[(4-Ethynyl)phenyl]sulfonyl}amino-3-phenyl-N-(tetrahydro-
solution of 10
a
The residue was crystallized from EtOH to obtain 8 as colorless (0.15 g, 0.45 mmol) in DMF (5 mL) were added HOBt (0.135 g,
crystals (1.89 g, 92%), mp 117–118 °C. (Found C, 43.15; H, 1 mmol), O-tetrahydro-2H-pyran-2-yl-hydroxylamine (0.107 g,
3.67; N, 3.38; S, 7.19; C16H16INO4S requires: C, 43.16; H, 3.62; 0.9 mmol), EDCI (0.2 g, 1.09 mmol) and NMM (0.15 mL,
N, 3.15; S, 7.20%). νmax (KBr)/cm−1 3291, 1731, 1569. δH 1.37 mmol). The reaction mixture was stirred overnight at
(300 MHz, CDCl3) 2.95–3.11 (2H, m, CH2Ar), 3.56 (3H, s, CH3), room temperature and then diluted with EtOAc (50 mL) and
4.15–4.23 (1H, m, CH), 5.18 (1H, d, J 9.2, SO2NH), 7.04–7.07 washed successively with a saturated aqueous solution of
(2H, m, ArH), 7.24–7.25 (3H, m, ArH), 7.41 (2H, d, J 8.7, ArH), NH4Cl and brine. The organic layer was dried (MgSO4), evapor-
7.77 (2H, d, J 8.7, ArH); δC (75.4 MHz, CDCl3) 39.2, 52.5, 56.7, ated to dryness, and the residue was purified by column
100.1, 127.3, 128.4, 128.6, 129.2, 134.7, 138.1, 139.1, 171.1. MS chromatography on silica gel (hexane–AcOEt 7 : 3) to afford 11
(ESI+) m/z 467.88 [M + Na]+.
(0.135 g, 69%) as a white solid. This compound is present as a
Methyl 3-phenyl-2-{[(4-trimethylsilanylethynyl)phenylsulfo- diastereoisomeric mixture (55 : 45), mp 148–149 °C. (C, 61.86;
nyl]amino}propanoate (9). To a mixture of 8 (1 g, 2.24 mmol), H, 5.69; N, 6.61; S, 7.34; C22H24N2O5S requires: C, 61.67; H,
triphenylphosphine (94 mg, 359 µmol), bis(triphenylphos- 5.65; N, 6.54; S, 7.48%). νmax (KBr)/cm−1 3276, 3202, 2110,
phine)palladium(II) dichloride (120 mg, 170 µmol), and 1660. δH (300 MHz, CDCl3) 1.57–1.77 (6H, m, 3 × CH2),
copper(I) iodide (20 mg, 110 µmol) in degassed acetonitrile– 2.88–3.07 (2H, m, CH2Ar), 3.27 (1H, s, ArCCH), 3.55–3.59 (1H,
NEt3 (5 mL/3.5 mL) was added (trimethylsilyl)acetylene m, CH), 3.80–3.89 (2H, m, CH2O), 4.7 (0.55H, s, O–CH–O,
(0.38 mL, 2.70 mmol) under a nitrogen atmosphere. The reac- isomer a), 4.79 (0.45H, s, O–CH–O, isomer b), 5.43 (1H, bs,
tion mixture was refluxed for 20 h. After cooling to room temp- SO2NH), 6.99 (2H, d, J 7.32, ArH), 7.18–7.22 (3H, m, ArH), 7.48
erature, methanol was added and the mixture was filtered over (2H dd, J 8.3, 2.8, ArH) 7.58 (2H dd, J 8.3, 2.8, ArH), 8.79
Celite and the solvent was evaporated under reduced pressure. (0.55H, s, CONH, isomer a), 9.09 (0.45H, s, CONH, isomer b);
The residue was dissolved in dichloromethane, and the solu- δC (75.4 MHz, CDCl3) 18.4, 24.8, 27.8, 38.9, 56.4, 62.4, 80.9,
tion was washed with an HCl aqueous solution. The extracts 82.2, 102.5, 126.8, 126.9, 127.3, 128.8, 128.9, 129.1, 132.7,
were dried using anhydrous MgSO4, filtered, and evaporated. 134.9, 162.7. MS (ESI+) m/z = 451.14 [M + Na]+.
The residue was purified by column chromatography on silica
2-{[4-(1-Biphenyl-4-yl-1H-1,2,3-triazol-4-yl)phenyl]sulfonyl}-
gel with ethyl hexane–EtOAc (4 : 1) to give 9 (0.69 g, 74%) as a amino-3-phenyl-N-(tetrahydro-2H-pyran-2-yloxy)propanamide
white solid, mp. 118–119 °C (DCM–hexane). (C, 60.74; H, 5.96; (12). General procedure 1: from 11 (50 mg, 0.117 mmol), 4-azido-
N, 3.50; S, 7.66; C21H25NO4SSi requires: C, 60.69; H, 6.06; N, biphenyl28 (23 mg, 0.117 mmol), sodium ascorbate (234 μL,
3.37; S, 7.72%). ]+. νmax (KBr)/cm-1 3239, 2154, 1745, 1587. δH 0.234 mmol) and copper(II) sulfate pentahydrate (234 μL,
(300 MHz, CDCl3) 0.27 (9H, s, (CH3)3Si), 2.97–3.09 (2H, m, 0.06 mmol) in DMF (3 mL), 12 (84.8 mg, 67%) was produced.
CH2Ar), 3.52 (3H, s, OCH3), 4.17–4.24 (1H, m, CH), 5.29 (1H, d, The reaction mixture was diluted in EtOAc and washed with
J 9.2, SO2NH), 7.05–7.23 (2H, m, ArH), 7.24–7.26 (3H, m, ArH), 30% aqueous NH3, 6 M HCl and brine. The organic layer was
7.49 (2H, d, J 8.3 Hz, ArH), 7.66 (2H, d, J 8.3, ArH); δC dried (MgSO4), evaporated to dryness, and the residue was sus-
(75.4 MHz, CDCl3) −0.3, 39.1, 52.4, 56.6, 98.4, 102.9, 126.8, pended in CHCl3 and filtered off to obtain a white solid
127.2, 127.7, 129.3, 132.2, 134.7, 138.9, 171.0. MS (ESI+) m/z (47 mg, 64%), mp 203–204 °C. (C, 65.26; H, 5.27; N, 11.26;
438.10 [M + Na]+.
S, 5.13; C34H33N5O5S requires: C, 65.47; H, 5.33; N, 11.23;
2-{[(4-Ethynylphenyl)sulfonyl]amino}-3-phenylpropanoic acid S, 5.14%); found: νmax (KBr)/cm−1 3210, 1664, 1602. δH
(10). To a solution of 9 (0.25 g, 0.6 mmol) in dioxane (3 mL) (300 MHz, DMSO-d6) 1.36–1.60 (6H, m, 3 × CH2), 2.64–2.72
1
1
2
was added KOH (1 M in water, 3 mL), and the mixture was (1H, m, CH2Ar), 2.79–2.85 (1H, m, CH2Ar), 3.39–3.51 (1H, m,
2
stirred at room temperature for 3 h. The solvent was removed CH), 3.81–3.85 (1H, m, OCH2, isomer a), 3.91–3.96 (1H, m,
under reduced pressure. The residue was diluted in water OCH2, isomer b), 4.38 (0.55H, s, O–CH–O, isomer a), 4.56
(50 mL), acidified to pH 3 with 20% solution of citric acid, and (0.45H, s, O–CH–O, isomer b), 7.10–7.13 (1H, m, ArH),
extracted with EtOAc (2 × 50 mL). The collected organic phase 7.16–7.23 (4H, m, ArH), 7.43–7.45 (1H, m, ArH), 7.50–7.55 (2H,
was washed with saturated solution of NH4Cl (2 × 50 mL) and m, ArH), 7.70–7.74 (2H, m, ArH), 7.79 (2H, d, J 8.6, ArH),
brine (50 mL), dried over MgSO4 and evaporated. The residue 7.95–8.09 (6H, m, ArH), 8.34–8.42 (1H, m, SO2NH), 9.54 (1H, s,
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 153

View Article Online
Paper
Organic & Biomolecular Chemistry
triazole), 11.23 (0.55H, s, CONH, isomer b), 11.33 (0.45H, s, 129.2, 129.4, 136.3, 136.6, 144.6, 169.4. MS (ESI+): m/z =
CONH, isomer a); δC (75.4 MHz, DMSO-d6) 18.6, 24.9, 28.0, 516.1 [M + H]+.
38.8, 55.5 (55.6 b), 61.3, 101.4, (101.6 b), 120.8, 121.1, 125.8,
126.8, 127.1, 127.4, 128.4 (128.4 b), 129.4, 129.5, 129.6, 133.9, amino}-3-phenylpropanoic acid (17). To
136.0, 136.9, 137.2, 139.0, 140.8 (140.8 b), 140.9, 146.4, 167.0 (0.82 g, 1.58 mmol) and thioanisole (3.34 mL, 28.45 mmol) in
(167.1 b). MS (ESI+) m/z 646.24 [M + Na]+.
DCM (4 mL) at 0 °C was added TFA (3.65 mL, 47.4 mmol). The
(2R)-2-{[(4-Azidophenyl)sulfonyl][2-(morpholin-4-yl)ethyl]-
a
mixture of 16
2-{[4-(1-Biphenyl-4-yl-1H-1,2,3-triazol-4-yl)phenyl]sulfonyl}- reaction was stirred at room temperature overnight and evapo-
amino-N-hydroxy-3-phenylpropanamide (7). General procedure rated to dryness. The residue was purified by column chro-
2: from 12 (54.2 mg, 0.073 mmol), MeOH (0.1 mL) and 4 M matography on silica gel (DCM–MeOH 9 : 1) to afford 17
HCl–dioxane (0.1 mL, 0.4 mmol), 7 was produced as a white (580 mg, 80%) as a white foam, mp 160.2 °C (dec.). νmax (KBr)/
solid (30.0 mg, 77%), mp 223 °C (dec.); (C, 63.66; H, 4.77; cm−1 3430, 2926, 2131, 2101, 1617, 1591. δH (400 MHz, DMSO-
N, 12.71; S, 5.85, C29H25N5O4S·1/3H2O requires: C, 63.84; H, d6) 2.70–3.05 (7H, m), 3.45–3.60 (3H, m), 3.60–3.80 (4H, m),
4.74; N, 12.84; S, 5.88%) νmax (KBr)/cm−1 3254, 1649, 1605. 4.79 (1H, dd, J = 9.7, 3.9), 6.94 (2H, d, J 8.4 ArH), 7.12–7.23
δH (300 MHz, DMSO-d6) 2.65 (1H, dd, J 13.5, 8.7, 12CH2Ar), 2.83 (5H, m, ArH), 7.60 (2H, d, J 8.4, ArH); δC (100.6 MHz, DMSO-
(1H, dd, J 13.5, 6.1, 1CH2), 3.82–3.90 (1H, m, CH), 7.09–7.18 d6) 36.9, 41.0, 52.4, 56.9, 62.9, 64.5, 119.1, 126.6, 128.5, 128.9,
2
(6H, m, ArH), 7.40–7.45 (1H, m, ArH), 7.50–7.55 (2H, m, ArH), 129.3, 135.6, 137.8, 144.5, 174.7. MS (ESI+): m/z = 460.1 [M + H]+.
7.69 (2H, d, J 8.4, ArH), 7.78 (2H, d, J 7.4, ArH), 7.94–8.01 (4H,
(2R)-2-{[(4-Azidophenyl)sulfonyl][2-(morpholin-4-yl)ethyl]-
m, ArH), 8.08 (2H, d, J 8.6, ArH), 8.28 (1H, d, J 8.8, SO2NH), amino}-N-(tetrahydro-2H-pyran-2-yl)-3-phenylpropanamide
8.86 (1H, s, CONHOH), 9.50 (1H, s, triazole), 10.65 (1H, s, (18). To a solution of 17 (543 mg, 1.18 mmol) in DMF (5 mL)
CONHOH); δC (75.4 MHz, DMSO-d6) 38.4, 55.4, 120.4, 120.6, were added HOBt (192 mg, 1.42 mmol), NMM (0.39 mL,
125.3, 126.2, 126.6, 126.8, 127.9, 128.0, 128.9, 129.1, 133.4, 3.55
135.6, 136.8, 138.6, 140.4, 140.5, 146.0, 166.0. MS (ESI+): m/z = (277 mg, 2.36 mmol) and EDCI (317 mg, 1.65 mmol). The reac-
562.25 [M + Na]+.
tion mixture was stirred overnight at room temperature and
mmol),
O-tetrahydro-2H-pyran-2-yl-hydroxylamine
tert-Butyl (2R)-2-{[(4-azidophenyl)sulfonyl]amino}-3-phenyl- then diluted with AcOEt and washed successively with a satu-
propanoate (15). To a solution of (R)-4 (4.08 g, 11.77 mmol) in rated aqueous solution of NH4Cl and brine. The organic layer
DCM (100 mL) was added concentrated H2SO4 (0.2 mL) and was dried (MgSO4), evaporated to dryness and the solid
the solvent was saturated with 2-methylpropene. After 24 h, obtained was purified by column chromatography on silica gel
water was added, neutralized with NaHCO3 and extracted with (hexane–AcOEt 2 : 3) to afford 18 (600 mg, 91%). This com-
DCM. The organic layer was dried (MgSO4), filtered and evap- pound is present as a diastereoisomeric a : b mixture (60 : 40),
orated to dryness, and the residue was chromatographed on mp 59.8–61.5 °C. νmax (KBr)/cm−1 3206, 2126, 2101, 1693,
silica gel (hexane–AcOEt 4 : 1) to give 15 (4.05 g, 86%) as a 1592; δH (400 MHz, CDCl3) 1.50–1.65 (3H, m), 1.68–1.85 (3H,
yellowish solid, mp 75.5–77.4 °C. νmax (KBr)/cm−1 3271, 2135, m), 2.35–2.47 (2H, m), 2.50–2.65 (4H, m), 2.65–2.85 (1H, m),
2106, 1730, 1589. δH (400 MHz, DMSO-d6) 1.15 (9H, s, (CH3)3), 3.25–3.52 (2H, m), 3.54–3.82 (6H, m), 3.94–4.02 (0.6H, m,
2.91 (1H, dd, J 6.4, 1.3, CH2Ar), 3.94–4.04 (1H, m, CH), 5.43 isomer a), 4.05–4.13 (0.4H, m, isomer b), 4.42–4.49 (0.4H, m,
(1H, d, J 9.3 NH), 6.93 (2H, d, J 8.7 ArH), 7.01–7.08 (2H, m, isomer b), 4.50–4.55 (0.6H, m, isomer a), 4.84 (0.6H, d, J 2.6,
ArH), 7.09–7.20 (3H, m, ArH), 7.64 (2H, d, J 8.7, ArH); δC isomer a), 4.97 (0.4H, s, isomer b), 6.90–7.03 (4H, m, ArH),
(100.6 MHz, DMSO-d6) 27.7, 39.5, 57.1, 82.7, 119.3, 127.1, 7.08–7.18 (3H, m, ArH), 7.58 (1.2H, d, J 8.6, ArH, isomer a),
128.4, 129.2, 129.6, 135.4, 136.2, 144.6, 170.0. MS (ESI+): m/z = 7.64 (0.8H, d, J 8.5, ArH, isomer b), 11.01 (0.4H, bs, CONH,
401.2 [M − H]+.
isomer b), 11.13 (0.6H, bs, CONH, isomer a); δC (100.6 MHz,
tert-Butyl (2R)-2-{[(4-azidophenyl)sulfonyl][2-(morpholin-4- CDCl3): 18.9 (isomer b), 19.5 (isomer a), 25.0, 28.1 (isomer b),
yl)ethyl]amino}-3-phenylpropanoate (16). To a solution of 15 28.3 (isomer a), 34.4 (isomer a), 34.7 (isomer b), 41.6 (isomer
(0.8 g, 1.99 mmol) in DMF (10 mL) were added K2CO3 (0.69 g, a), 42.0 (isomer b), 53.5, 57.0 (isomer b), 57.2 (isomer a), 59.9
4.97 mmol) and 4-(2-chloroethyl)morpholine hydrochloride (isomer a), 60.0 (isomer b), 62.9 (isomer b), 63.4 (isomer a),
(0.44 g, 2.39 mmol). The reaction was heated for 24 h at 80 °C 66.4 (isomer a), 66.5 (isomer b), 102.5 (isomer b), 103.3
and, after cooling, was diluted with ethyl acetate and washed (isomer a), 119.4, 126.7, 128.6, 128.8, 128.9, 135.4 (isomer a),
successively with saturated aqueous NH4Cl and brine. The 135.6 (isomer b), 136.7 (isomer a), 137.0 (isomer b), 144.7,
extract was dried (MgSO4), filtered off and evaporated to 167.9 (isomer a), 168.1 (isomer b). MS (ESI) m/z 559.1 [M + H]+.
dryness, and the residue was chromatographed on silica
(2R)-2-[({4-[4-(Biphenyl-4-yl)-1H-1,2,3-triazol-1-yl]phenyl}sul-
gel (hexane–AcOEt 3 : 2) to give 16 (872 mg, 85%) as a yellow fonyl)(2-[morpholin-4-yl]ethyl)amino]-3-phenyl-N-(tetrahydro-
oil. νmax (KBr)/cm−1 2971, 2853, 2806, 2129, 2106, 2106, 1730, 2H-pyran-2-yloxy)propanamide (19). The product was prepared
1589. δH (400 MHz, DMSO-d6) 1.25 (9H, s), 2.38–2.56 (5H, m), by General procedure 1 (preparation of triazoles), using
2.57–2.65 (1H, m), 2.97 (1H, dd, J = 14.0, 7.2), 2.97 (1H, dd, 18 (150 mg, 0.269 mmol), 4-ethynylbiphenyl (57.4 mg,
J = 14.0, 8.2), 3.34–3.53 (2H, m), 3.68 (4H, t, J 4.6), 4.67 0.322 mmol), sodium ascorbate (106 mg, 0.537 mmol) and
(1H, t, J 7.7), 7.04 (2H, d, J 8.7 ArH), 7.18–7.31 (5H, m, ArH), copper(II) sulfate pentahydrate (33.5 mg, 0.134 mmol) in DMF
7.73 (2H, d, J 8.7, ArH); δC (100.6 MHz, DMSO-d6) 27.7, (5 mL); 19 (145 mg, 73%) was produced as a white solid after
37.3, 42.7, 53.9, 58.8, 61.7, 66.9, 82.2, 119.2, 126.9, 128.5, chromatography purification (DCM–MeOH 1% MeOH). This
154 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015

View Article Online
Organic & Biomolecular Chemistry
Paper
compound is present as a diastereoisomeric a : b mixture HCl–dioxane (2 mL). The crude was purified by chromato-
(60 : 40), mp 196.1 °C (dec.). νmax (KBr)/cm−1 3374, 2951, 2854, graphy (DCM–MeOH 4% MeOH) to obtain 13 (66.0 mg, 60%)
2814, 1704, 1597; δH (400 MHz, CDCl3) 1.50–1.65 (3H, m), as a white solid, mp 208 °C (dec.). (Found: C, 64.31; H, 5.68;
1.70–1.88 (3H, m), 2.40–2.54 (2H, m), 2.56–2.70 (4H, m), N, 12.51; S, 4.67. C29H25N5O4S·H2O requires: C, 64.40; H, 5.56;
2.75–2.85 (1H, m), 3.35–3.85 (8H, m), 3.94–4.02 (0.6H, m, N, 12.87; S, 4.91%). νmax (KBr)/cm−1 3470, 3129, 1668, 1622,
isomer a), 4.05–4.13 (0.4H, m, isomer b), 4.50–4.59 (1H, m), 1597. δH (400 MHz, DMSO-d6): 2.38–2.59 (6H, m, 3 × NCH2),
1
2
4.89 (0.6H, d, J 2.7, isomer a), 5.01 (0.4H, s, isomer b), 2.80 (1H, dd, J = 13.9, 7.1, CH2Ph), 2.97 (1H, dd, J = 14.0, 8.1,
6.92–7.00 (2H, m, ArH), 7.04–7.08 (3H, m, ArH), 7.36 (1H, t, 1CH2Ph), 3.40–3.46 (1H, m, 1SO2NCH2), 3.58 (4H, t, J 4.5,
2
2
J 7.3, ArH), 7.45 (2H, t, J 7.5, ArH), 7.63 (2H, d, J 7.5, ArH), 2 × OCH2), 3.63–3.74 (1H, m, 1SO2NCH2), 4.48 (1H, t, J 7.5,
2
7.62–7.78 (6H, m, ArH), 7.99 (2H, d, J 8.2, ArH), 8.34 (1H, s, CH), 7.14–7.24 (5H, m, ArH), 7.41 (1H, t, J 7.3, ArH), 7.51 (2H,
triazole), 11.12 (0.4H, bs, CONH, isomer b), 11.24 (0.6H, bs, t, J 7.6, ArH), 7.76 (2H, d, J 7.5, ArH), 7.85 (2H, d, J 8.3, ArH),
CONH, isomer a); δC (100.6 MHz, CDCl3): 19.0 (isomer b), 19.6 8.03 (2H, d, J 8.8, ArH), 8.08 (2H, d, J 8.3, ArH), 8.14 (2H, d,
(isomer a), 25.0, 28.2 (isomer b), 28.4 (isomer a), 34.4, 41.8 J 8.7, ArH), 8.93 (1H, bs, OH), 9.54 (s, 1H, CH triazole), 10.96
(isomer a), 42.2 (isomer b), 53.4, 57.0 (isomer b), 57.2 (isomer (s, 1H, CONH); δC (100.6 MHz, DMSO-d6) 36.0, 41.7, 53.33,
a), 60.4 (isomer a), 60.5 (isomer b), 63.0 (isomer b), 63.6 58.0, 58.3, 66.1, 119.8, 120.1, 125.9, 126.5, 126.6, 127.2, 127.7,
(isomer a), 66.5 (isomer a), 66.6 (isomer b), 102.8 (isomer b), 128.3, 129.0, 136.6, 139.0, 139.3, 139.4, 140.0, 147.3, 165.5. MS
103.5 (isomer a), 114.1, 117.3 (isomer a), 117.4 (isomer b), (ESI+): m/z 653.1 [M + H]+. [α]D25 + 12.2 (c 0.0018 g cm−3 in DMSO).
120.3, 123.6, 126.4, 126.9, 127.0, 127.7, 128.6, 128.7, 128.8,
(2R)-N-Hydroxy-2-[(2-[morpholin-4-yl]ethyl)({4-[4-(4-phenoxy-
128.9, 128.9, 129.0, 136.6 (isomer a), 136.9 (isomer b), 139.2, phenyl)-1H-1,2,3-triazol-1-yl]phenyl}sulfonyl)amino]-3-phenyl-
139.3, 139.3, 139.7, 140.3, 140.5, 141.5, 148.7, 168.0 (isomer a), propanamide (14). The product was prepared by General
168.2 (isomer b). MS (ESI) m/z 737.1 [M + H]+.
procedure 2 (cleavage of tetrahydropyrane protecting group)
(2R)-2-[(2-[Morpholin-4-yl]ethyl)({4-[4-(4-phenoxyphenyl)-1H- using 20 (130 mg, 0.17 mmol), MeOH (0.5 mL) and 4 M HCl–
1,2,3-triazol-1-yl]phenyl}sulfonyl)amino]-3-phenyl-N-(tetrahydro- dioxane (2 mL). The crude was purified by chromatography
2H-pyran-2-yloxy)propanamide (20). The product was prepared (DCM–MeOH 4% MeOH) to obtain 14 (64.0 mg, 56%) as a gray
by General procedure 1 (preparation of triazoles), using 18 solid, mp 131–133 °C. (Found: C, 64.31; H, 5.68; N, 12.51;
(150 mg, 0.269 mmol), 4-ethynylbiphenyl (57.4 mg, S, 4.67. C29H25N5O4S·H2O requires: C, 64.40; H, 5.56; N, 12.87;
0.322 mmol), sodium ascorbate (106 mg, 0.537 mmol) and S, 4.91%). νmax (KBr)/cm−1 3368, 3140, 1673, 1597. δH
copper(II) sulfate pentahydrate (33.5 mg, 0.134 mmol) in DMF (400 MHz, DMSO-d6): 2.33–2.60 (6H, m, 3 × NCH2), 2.79 (1H,
1
1
(5 mL); 20 (150 mg, 74%) was produced as a gray solid after dd, J = 13.8, 7.1, CH2Ph), 3.18 (1H, dd, J = 13.8, 7.8, CH2Ph),
2
2
chromatography purification (DCM–MeOH 1% MeOH). This 3.37–3.48 (1H, m, 1SO2NCH2), 3.58 (4H, t, J 4.5, 2 × OCH2),
compound is present as a diastereoisomeric a : b mixture 3.63–3.74 (1H, m, SO2NCH2), 4.47 (1H, t, J 7.5, CH), 7.09–7.24
2
1
2
(60 : 40), mp 81.5–82.9 °C. νmax (KBr)/cm−1 2956, 1693, 1597; (10H, m, ArH), 7.44 (1H, t, J 8.0, ArH), 7.97–8.02 (4H, m, ArH),
δH (400 MHz, CDCl3) 1.50–1.65 (3H, m), 1.70–1.85 (3H, m), 8.12 (2H, d, J 8.7, ArH), 8.93 (1H, bs, OH), 9.43 (s, 1H, CH tria-
2.44–2.52 (2H, m), 2.56–2.72 (4H, m), 2.75–2.86 (1H, m), zole), 10.96 (s, 1H, CONH); δC (100.6 MHz, DMSO-d6) 36.0,
3.38–3.85 (8H, m), 3.97–4.03 (0.6H, m, isomer a), 4.10–4.15 41.7, 53.3, 58.0, 58.3, 66.1, 118.9, 119.0, 119.3, 120.1, 123.8,
(0.4H, m, isomer b), 4.47–4.59 (1H, m), 4.89 (0.6H, d, J 2.7, 125.1, 126.5, 127.2, 128.3, 128.9, 129.0, 130.1, 136.6, 139.0,
isomer a), 5.01 (0.4H, s, isomer b), 6.94–7.00 (2H, m, ArH), 139.3, 147.2, 156.3, 156.9, 165.5. MS (ESI+): m/z 669.1 [M + H]+.
7.04–7.11 (7H, m, ArH), 7.15 (1H, t, J 7.4, ArH), 7.33–7.40 (2H, [α]2D5 + 4.0 (c 0.0005 g cm−3 in DMSO).
m, ArH), 7.71–7.80 (4H, m, ArH), 7.89 (2H, d, J 8.5, ArH), 8.27
(1H, s, triazole), 11.12 (0.4H, bs, CONH, isomer b), 11.25
(0.6H, bs, CONH, isomer a); δC (100.6 MHz, CDCl3): 19.0
(isomer b), 19.6 (isomer a), 25.0, 28.2 (isomer b), 28.4 (isomer
Conclusions
a), 34.4 (isomer a), 34.6 (isomer b), 41.7 (isomer a), 42.2 We have used a click chemistry approach to synthesize a series
(isomer b), 53.4, 57.0 (isomer b), 57.1 (isomer a), 60.4 (isomer of phenylalanine derived hydroxamates. The substitution
a), 60.5 (isomer b), 63.1 (isomer b), 63.6 (isomer a), 66.5 pattern in the resulting triazole seems to be crucial to obtain a
(isomer a), 66.6 (isomer b), 102.8 (isomer b), 103.5 (isomer a), high degree of selectivity between both gelatinases. The best
114.1, 116.8 (isomer a), 116.9 (isomer b), 119.0, 119.3, 120.3, compound 1b displayed subnanomolar IC50 against MMP-2
123.8, 124.6, 126.9, 127.5, 128.7, 128.8, 128.8, 128.9, 128.9, and was 95-fold less potent against MMP-9, while the closely
129.0, 136.5 (isomer a), 136.8 (isomer b), 139.1, 139.3, 139.7, structurally related compound 7 was devoid of selectivity. We
148.6, 156.6, 158.0 168.0 (isomer a), 168.2 (isomer b). MS (ESI) have used docking and molecular dynamics tools to shed light
m/z 753.1 [M + H]+.
on the reason for this difference in selectivity between 1b and
(2R)-2-[({4-[4-(Biphenyl-4-yl)-1H-1,2,3-triazol-1-yl]phenyl}sul- 7. The difference in the energetic profile of the dihedral angle
fonyl)(2-[morpholin-4-yl]ethyl)amino]-N-hydroxy-3-phenylpro- that describes the torsion around Csp2–Csp2 and Csp2–Nsp2
panamide (13). The product was prepared by General induces a change in the dynamic behaviour of the P1′-segment
procedure 2 (cleavage of tetrahydropyrane protecting group) that allows 7 to establish good interactions with both MMP-2
using 19 (125 mg, 0.17 mmol), MeOH (0.5 mL) and 4 M and MMP-9.
This journal is © The Royal Society of Chemistry 2015
Org. Biomol. Chem., 2015, 13, 142–156 | 155

View Article Online
Paper
Organic & Biomolecular Chemistry
26 Y. Tamura, F. Watanabe, T. Nakatani, K. Yasui, M. Fuji,
T. Komurasaki, H. Tsuzuki, R. Maekawa, T. Yoshioka,
K. Kawada, K. Sugita and M. Ohtani, J. Med. Chem., 1998,
41, 640–649.
Notes and references
1 M. Yamamoto, S. Ikeda, H. Kondo and S. Inoue, Bioorg.
Med. Chem. Lett., 2002, 12, 375–378.
2 S. Rivera, M. Khrestchatisky, L. Kaczmarek, G. A. Rosenberg 27 M. L. Di Gioia, A. Leggio and A. Liguori, J. Org. Chem.,
and D. M. Jaworski, J. Neurosci., 2010, 30, 15337–15357. 2005, 70, 3892–3897.
3 J. Huxley-Jones, T.-K. Clarke, C. Beck, G. Toubaris, 28 F. R. Bou-Hamdan, F. Levesque, A. G. O’Brien and
D. L. Robertson and R. P. Boot-Handford, BMC Evol. Biol.,
2007, 7, 63.
4 W. Bode, F. X. Gomisruth and W. Stockler, FEBS Lett., 1993,
331, 134–140.
5 R. Roy, J. Yang and M. A. Moses, J. Clin. Oncol., 2009, 27,
5287–5297.
6 B. Fingleton, Curr. Pharm. Des., 2007, 13, 333–346.
7 T. Klein and R. Bischoff, Amino Acids, 2011, 41, 271–290.
8 T. P. Theruvath, J. A. Jones and J. S. Ikonomidis, J. Card.
Surg., 2012, 27, 81–90.
P. H. Seeberger, Beilstein J. Org. Chem., 2011, 7, 1124–1129.
29 Y. Q. Feng, J. J. Likos, L. M. Zhu, H. Woodward, G. Munie,
J. J. McDonald, A. M. Stevens, C. P. Howard, G. A. De Cres-
cenzo, D. Welsch, H. S. Shieh and W. C. Stallings, Biochim.
Biophys. Acta, Proteins Proteomics, 2002, 1598, 10–23.
30 L. J. MacPherson, E. K. Bayburt, M. P. Capparelli,
B. J. Carroll, R. Goldstein, M. R. Justice, L. Zhu, S. Hu,
R. A. Melton, L. Fryer, R. L. Goldberg, J. R. Doughty,
S. Spirito, V. Blancuzzi, D. Wilson, E. M. O’Byrne, V. Ganu
and D. T. Parker, J. Med. Chem., 1997, 40, 2525–2532.
9 M. L. Lindsey and R. Zamilpa, Cardiovasc. Ther., 2012, 30, 31 D. P. Becker, T. E. Barta, L. J. Bedell, T. L. Boehm,
31–41.
B. R. Bond, J. Carroll, C. P. Carron, G. A. DeCrescenzo,
A. M. Easton and J. N. Freskos, J. Med. Chem., 2010, 53,
6653–6680.
10 G. Siasos, D. Tousoulis, S. Kioufis, E. Oikonomou, Z. Siasou,
M. Limperi, A. G. Papavassiliou and C. Stefanadis, Curr. Top.
Med. Chem., 2012, 12, 1132–1148.
11 P. S. Burrage, K. S. Mix and C. E. Brinckerhoff, Front.
Biosci., 2006, 11, 529–543.
32 T. Tuccinardi, A. Martinelli, E. Nuti, P. Carelli, F. Balzano,
G. Uccello-Barretta, G. Murphy and A. Rossello, Bioorg.
Med. Chem., 2006, 14, 4260–4276.
12 A. Davey, D. F. McAuley and C. M. O’Kane, Eur. Respir. J., 33 M. D. Martin and L. M. Matrisian, Cancer Metastasis Rev.,
2011, 38, 959–970.
2007, 26, 717–724.
13 K. Kessenbrock, V. Plaks and Z. Werb, Cell, 2010, 141, 52–67.
14 F. Vasaturo, F. Solai, C. Malacrino, T. Nardo, B. Vincenzi,
M. Modesti and S. Scarpa, Oncol. Lett., 2013, 5, 316–320.
15 D. Stellas and E. Patsavoudi, Anti-Cancer Agents Med.
Chem., 2012, 12, 707–717.
34 S. A. Kolodziej, S. L. Hockerman, T. L. Boehm, J. N. Carroll,
G. A. DeCrescenzo, J. J. McDonald, D. A. Mischke,
G. E. Munie, T. R. Fletcher, J. G. Rico, N. W. Stehle,
C. Swearingen and D. P. Becker, Bioorg. Med. Chem. Lett.,
2010, 20, 3557–3560.
16 B. Bauvois, Biochim. Biophys. Acta, Rev. Cancer, 2012, 1825, 35 B. Fabre, K. Filipiak, C. Coderch, J. M. Zapico,
29–36.
R. J. Carbajo, A. K. Schott, A. Pineda-Lucena, B. de Pascual-
Teresa and A. Ramos, RSC Adv., 2014, 4, 17726–17735.
36 S. H. Hilal, S. W. Karickhoff and L. A. Carreira, Quant.
Struct-Act. Relat., 1995, 14, 348–355.
17 T. Itoh, M. Tanioka, H. Yoshida, T. Yoshioka, H. Nishimoto
and S. Itohara, Cancer Res., 1998, 58, 1048–1051.
18 C. M. Overall and O. Kleifeld, Nat. Rev. Cancer, 2006, 6, 227–239.
19 P. Serra, M. Bruczko, J. M. Zapico, A. Puckowska, M. A. Garcia, 37 R. A. Friesner, R. B. Murphy, M. P. Repasky, L. L. Frye,
S. Martin-Santamaria, A. Ramos and B. de Pascual-Teresa,
J. R. Greenwood, T. A. Halgren, P. C. Sanschagrin and
Curr. Med. Chem., 2012, 19, 1036–1064.
D. T. Mainz, J. Med. Chem., 2006, 49, 6177–6196.
20 M. Whittaker, C. D. Floyd, P. Brown and A. J. H. Gearing, 38 T. A. Halgren, R. B. Murphy, R. A. Friesner, H. S. Beard,
Chem. Rev., 1999, 99, 2735–2776.
21 R. K. Yadav, S. P. Gupta, P. K. Sharma and V. M. Patil, Curr.
Med. Chem., 2011, 18, 1704–1722.
22 R. P. Verma and C. Hansch, Bioorg. Med. Chem., 2007, 15,
2223–2268.
23 J. M. Zapico, P. Serra, J. Garcia-Sanmartin, K. Filipiak,
L. L. Frye, W. T. Pollard and J. L. Banks, J. Med. Chem.,
2004, 47, 1750–1759.
39 R. A. Friesner, J. L. Banks, R. B. Murphy, T. A. Halgren,
J. J. Klicic, D. T. Mainz, M. P. Repasky, E. H. Knoll,
M. Shelley, J. K. Perry, D. E. Shaw, P. Francis and
P. S. Shenkin, J. Med. Chem., 2004, 47, 1739–1749.
R. J. Carbajo, A. K. Schott, A. Pineda-Lucena, A. Martinez, 40 W. L. Jorgensen, J. Chandrasekhar, J. D. Madura,
S. Martin-Santamaria, B. de Pascual-Teresa and A. Ramos,
Org. Biomol. Chem., 2011, 9, 4587–4599.
R. W. Impey and M. L. Klein, J. Chem. Phys., 1983, 79, 926–935.
41 J. Aaqvist, J. Phys. Chem., 1990, 94, 8021–8024.
24 B. Fabre, K. Filipiak, J. M. Zapico, N. Diaz, R. J. Carbajo, 42 C. Hansch, J. Comput. Aided Mol. Des., 2011, 25, 495–507.
A. K. Schott, M. P. Martinez-Alcazar, D. Suarez, A. Pineda- 43 M. A. Lill, Biochemistry, 2011, 50, 6157–6169.
Lucena, A. Ramos and B. de Pascual-Teresa, Org. Biomol. 44 J. Klett, A. Nunez-Salgado, H. G. Dos Santos, A. Cortes-
Chem., 2013, 11, 6623–6641.
Cabrera, A. Perona, R. Gil-Redondo, D. Abia, F. Gago and
25 B. Fabre, K. Filipiak, N. Diaz, J. M. Zapico, D. Suarez,
A. Morreale, J. Chem. Theory Comput., 2012, 8, 3395–3408.
A. Pineda-Lucena, A. Ramos and B. de Pascual-Teresa, 45 A. Morreale, R. Gil-Redondo and A. R. Ortiz, Proteins, 2007,
ChemBioChem, 2014, 15, 399–412.
67, 606–616.
156 | Org. Biomol. Chem., 2015, 13, 142–156
This journal is © The Royal Society of Chemistry 2015