New Caffeic Acid Phenylethyl Ester Analogs Bearing Substituted Triazole: Synthesis and Structure-Activity Relationship Study towards 5-Lipoxygenase Inhibition

Article abstract of DOI:10.1155/2017/2380531

Leukotrienes are biosynthesized by the conversion of arachidonic acid by 5-Lipoxygenase and play a key role in many inflammatory disorders. Inspired by caffeic acid phenylethyl ester (CAPE) (2) and an analog carrying a triazole substituted by cinnamoyl an

Full text of DOI:10.1155/2017/2380531

Hindawi
Journal of Chemistry
Volume 2017, Article ID 2380531, 11 pages
https://doi.org/10.1155/2017/2380531
Research Article
New Caffeic Acid Phenylethyl Ester Analogs Bearing
Substituted Triazole: Synthesis and Structure-Activity
Relationship Study towards 5-Lipoxygenase Inhibition
Pierre-Philipe Roy, Diene Faye, Sébastien Blanchard, Marc Cormier,
Jérémie A. Doiron, Marc E. Surette, and Mohamed Touaibia
´
Department of Chemistry and Biochemistry, Universite de Moncton, Moncton, NB, Canada E1A 3E9
Correspondence should be addressed to Mohamed Touaibia; mohamed.touaibia@umoncton.ca
Received 27 February 2017; Accepted 9 April 2017; Published 4 May 2017
Academic Editor: Naoki Toyooka
Copyright © 2017 Pierre-Philipe Roy et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Leukotrienes are biosynthesized by the conversion of arachidonic acid by 5-Lipoxygenase and play a key role in many inflammatory
disorders. Inspired by caffeic acid phenylethyl ester (CAPE) (2) and an analog carrying a triazole substituted by cinnamoyl
and 5-LO inhibitors recently reported by our team, sixteen new CAPE analogs bearing substituted triazole were synthesized by
copper catalyzed Huisgen 1,3-dipolar cycloaddition. Compound 10e, an analog bearing p-CF3 phenethyl substituted triazole, was
equivalent to CAPE (2) but clearly surpassed Zileuton (2), the only approved 5-LO inhibitor. Substitution of the phenethyl moiety
by cyclohexylethyl, as with 12g, clearly increased 5-LO inhibition which confirms the importance of hydrophobic interactions.
Molecular docking revealed new hydrogen bonds and ꢀ-ꢀ interactions between the enzyme and some of the investigated
compounds. Overall, this work highlights the relevance of exploring polyphenolic compounds as leukotrienes biosynthesis
inhibitors.
1. Introduction
research group. Many studies reported by our laboratory have
also shown the potential of CAPE and its analogs as potential
anti-inflammatory compounds.
Leukotrienes (LTs) are a class of lipid mediators implicated
in inflammatory responses [1]. In recent years, many studies
have developed new pharmacological agent that influence the
biosynthesis or action of LTs [2]. Despite their implication in
inflammatory and allergic responses, LTs are also involved in
many inflammatory diseases like asthma, arthritis, irritable
bowel syndrome, and even cancer [3, 4].
Contrary to the belief that polyphenols inhibit 5-LO
exclusively through their antioxidant properties, our previous
results clearly show that the presence or absence of specific
functional groups influences 5-LO inhibition independent
of their impact on antioxidant activity [10, 11]. Structural
modifications which resulted from changes in the ester
structure showed significantly improved inhibition of 5-LO
when compared to Zileuton (2) [13], the only clinically
available 5-LO inhibitor. However, Zileuton (2) was shown to
have hepatotoxic effects, low potency, and short half-life [14];
therefore research continues for the development of new 5-
LO inhibitors.
5-Lipoxygenase (5-LO) is an enzyme that plays a crucial
role for the formation of LTs as it catalyzes the first two steps
of the conversion of arachidonic acid to the bioactive LTs
[5]. erefore, 5-LO is the preferred target for pharmaceutical
control of LTs biosynthesis [2]. Moreover, the inhibition of 5-
LO is a validated target for the treatment of asthma [6, 7]. 5-
LO inhibitors have also shown promising results in blocking
the proliferation of several tumors cell lines [8, 9].
In a previous work, an analog of caffeic acid bearing a
triazole (compound 3, Figure 1) emerged as the best inhibitor
of a series of analogs with 1 to 6 caffeoyl moieties [15]. Further
structure-activity relationship was performed later where
Recently, caffeic acid phenethyl ester (CAPE, 1) (Figure 1)
was found to be a potent 5-LO inhibitor [10–12] by our

2
Journal of Chemistry
S
O
O
HO
HO
O
N
NH2
HO
Zileuton (2)
CAPE (1)
O
O
O
HO
HO
8
()
AcO
AcO
N
O
N
N
O
N
N
N
(3) [15]
OH
(4) [17]
O
Figure 1: Structures of CAPE (1), Zileuton (2), compound (3) [15], and compound 4 [13].
O
O
HO
HO
HO
O
O
()n
N
N
R
N
N
N
N
HO
O
HO
HO
O
R
N
N
N
Figure 2: Caffeic acid phenylethyl ester analogs bearing substituted triazole designed in this study.
different triazoles containing cinnamic acid and caffeic acid
analogs were investigated for 5-LO inhibition [16]. De Lucia
also synthesized additional analogs [13] related to compound
3. Interestingly, they found that the length of the linker was
critical for the activity of the molecule; a longer linker had
better inhibition capacity [13]. While the importance of the
linker length is now relatively established, it is not clear if
the triazole needs to be far away from the caffeic acid moiety
and which type of substitution on the triazole moiety will
impact the 5-LO inhibition. It is also noteworthy that the
mechanism of inhibition of 5-LO by these CAPE analogs
bearing substituted triazole analogs is not well established [16,
17]. Moreover, structure-activity relationship studies (SAR)
are required to learn more about the potential mode of action
of these molecules.
In the present study, we describe the design and synthesis
of new caffeic acid phenylethyl ester analogs bearing sub-
stituted triazole derived from compound 3 (Figure 2). With
these analogs, the effect of the substitution of the triazole
moiety by a phenyl as well as the linker length between
the latter and triazole was investigated. e substitution of
the phenyl with electron-withdrawing and electron-donating
groups was also explored.
2. Results and Discussion
2.1. Chemistry. To investigate the structure-activity relation-
ship of compound 3, closely related analogs were synthesized.
We examined the molecular interaction that would have an
effect on 5-LO inhibition by linking with the Huisgen 1,3-
dipolar cycloaddition (commonly known as “click reaction”)
reaction different molecular groups on the caffeoyl moiety.
All analogs were synthesized by an efficient sequential proce-
dure that directly links the azides, which can be potentially
explosive, obtained from the commercially available organic
halides to the alkyne moiety of the caffeic propargylic ester.
As shown in Scheme 1, a first series of analogs was
synthesized to examine the effect of the length of the linker
between the triazole core and a nonsubstituted phenyl moiety.
Sequential synthesis of the appropriate organic azide
synthesized from the commercially available organic halides
(7a–c) followed by the copper catalyzed 1,3-dipolar cycload-
dition of these azides with (6) provided analogs 8a–8c
with one to three methylenes between the triazole and the
nonsubstituted phenyl moiety in moderate yield (Scheme 1).
To investigate the effect of substitution of the phenyl
of series 1 with electron-withdrawing and electron-donating
groups, new analogs were designed as shown in Scheme 2. As
compounds 8a-b were essentially equipotent with Zileuton
(2) and compound (3) (see results of LT inhibition below),
analogs of 8b with substituted phenyl were designed and
synthesized. It should also be mentioned that the acces-
sibility of the various halogenated derivatives with two
methylenes allowed us to make this series more easily
Finally, the substitution of the triazole with various allyl
groups of various sizes was also investigated. Afer anti-LTs
activity screening in a HEK293 cell model, 5-LO inhibition
potential of selected compounds was determined in human
polymorphonuclear leukocytes (PMNL). Moreover, a molec-
ular docking study was conducted to shine a new light on the
mechanism of inhibition of these compounds.

Journal of Chemistry
3
O
O
O
HO
HO
HO
HO
ii
iii
HO
HO
i
OH
O
O
(
N
N
n
N
6
5
8a: n = 1
8b: n = 2
8c: n = 3
Scheme 1: Synthesis of series 1: (i): propargyl bromide, Na CO , KI, HMPA, 0∘C-rt, overnight, 43%; (ii): appropriate aryl bromide (7a–c),
2
3
NaN , DMSO, rt, overnight; (iii): 6, CuSO ⋅5H O, sodium ascorbate, H O, rt, overnight (8a: 42%; 8b: 57%; 8c: 53%).
3
4
2
2
O
R
HO
HO
i
O
N
Br
R
N
ii
N
9a–f
10a: R=CH3,
10b: R=OCH3
10c: R=F
10d: R=OH
10e: R=CF3
10f: R=NO2
Scheme 2: Synthesis of series 2: (i): NaN , DMSO, rt, overnight; (ii) 6, CuSO ⋅5H O, sodium ascorbate, H O, rt, overnight (10a: 65%; 10b:
3
4
2
2
65%; 10c: 63%; 10d: 47%; 10e: 68%; 10f: 53%).
O
O
ii
HO
HO
HO
HO
i
O
R
X
O
R
R
N
N
iii
N
11a–h
N
N
N
12a (PP45)
12b: R=CH2CH3
12c: R=(CH2)2CH3
12d: R=CH(CH3)
2
12e: R=CH2CHC(CH3)
2
12f: R=(CH2) CH3
5
12g: R=(CH2) Cyclohexane
2
Scheme 3: Synthesis of series 3: (i):6, NaN , MeI, CuI, acetone/H O (1/1), rt, ultrasound, overnight (12a: 24%). (ii): NaN , DMSO, rt, overnight;
3
2
3
(iii): 6, CuSO ⋅5H O, Sodium ascorbate, H O, rt, overnight (12b: 59%; 12c: 55%; 12d: 54%; 12e: 63%; 12f: 22%; 12g: 51%).
4
2
2
following our sequential procedure (Scheme 2). Copper cat-
alyzed 1,3-dipolar cycloaddition of substituted phenethyl
azides obtained from the corresponding bromide analogs
(9a–f) with compound 6 provided analogs 10a–f with
electron-withdrawing and electron-donating substituents on
the phenyl moiety (Scheme 2).
To investigate the effect of the presence of hydrophobic
carbon chains, a third series of analogs was designed. In
this series, the triazole was substituted by various alkyls,
from the simpler (methyl) to branched alkyls. As shown in
Scheme 3 and following our sequential procedure, analogs
(12b–g) containing various alkyl groups linked to the triazole
were synthesized. Compound 12a could not be obtained
using the same method. is is probably due to the gaseous
nature of methyl azide. erefore, another method was used
to obtain the methyl-substituted triazole analog (12a). With
a one-pot procedure, we were able to obtain the desired
methyl-substituted triazole by copper catalyzed 1,3-dipolar
cycloaddition of the methyl azide, formed in situ by the
substitution reaction of methyl iodine and sodium azide, with
the caffeic propargylic ester 6 (Scheme 3).
2.2. Biological Evaluation
2.2.1. Inhibition of 5-LO Products Synthesis in Whole HEK293
Cells. Inhibition of leukotriene biosynthesis was assayed in
intact HEK293 cells that are stably transfected with human 5-
LO. is model serves as a highly reproducible model of 5-LO
product biosynthesis in which compounds can be preliminar-
ily screened for anti-LTs activity before moving on to more
complex systems [11]. All compounds were assayed at 1 ꢁM,
including known inhibitors CAPE (1) and Zileuton (2) whose
inhibitory potencies were used as reference points (Figure 3).
As shown in Figure 3, analogs 8a–c having one- to three-
methylene linker between the triazole and the nonsubstituted
phenyl moiety are equivalent to Zileuton but remain less
active than CAPE (1). Analog8c, with three-methylene linker,
is the most active of the three compounds with an inhibition
at around 50%, which clearly surpasses Zileuton (2). e
small difference in lipophilicity between these molecules can
probably explain the small difference in activity.
In order to investigate the effect of substitution of
the 8b benzylic ring, analogs with electron-withdrawing

4
Journal of Chemistry
100
50
0
100
50
0
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
Test compound (1ꢀM)
Test compound (1ꢀM)
Figure 5: Inhibition of 5-LO products synthesis by 12a–c and
8b in whole HEK293 cells. Values are the means SEM of
Figure 3: Inhibition of 5-LO products synthesis by analogs (8a–c) in
whole HEK293 cells. Values are the means SEM of three indepen-
dent experiments, each performed in quadruplicate; ∗different from
control (diluent) as determined by one-way ANOVA with Dunnett’s
multiple comparison test (ꢂ < 0.05).
three independent experiments, each performed in quadruplicate;
∗different from control (diluent) as determined by one-way ANOVA
with Dunnett’s multiple comparison test (ꢂ < 0.05).
100
for 5-LO inhibition; the induction of -CF analog increases
3
∗
∗
the inhibitory capacity of 8b by almost 30%. Compound
10e is equivalent to CAPE (1) but clearly surpasses the
Zileuton (2) (Figure 4). e difference of lipophilicity is not as
important in explaining the difference of 5-LO inhibition of
8b, 10a, and 10e; an electronic effect associated with favorable
interactions due to the presence of fluorine atoms can explain
this difference.
∗
∗
∗
∗
∗
∗
50
0
∗
∗
It would have been supposed that the accentuation of
the deactivating effect on phenyl by strong withdrawing
substituents such as nitro group could increase the activity
even more. However, as shown in Figure 4, the substitution
of phenyl with a nitro considerably reduces the effect of 10f,
which becomes less active than 10e. Analog 10f was even less
potent than the unsubstituted analog 8b (Figure 4).
In order to investigate the presence of a hydrophobic
group, hydrophobic chains of different sizes and degrees of
substitution were tested in the third series. As shown in
Figure 5, some molecules were significantly less active than
CAPE (1), Zileuton (2), and analog 3. Analogs 12e and 12f
were equivalent to Zileuton (2) and analog 3. Analog 12g was
the most active of the whole while being also much more
active than the Zileuton and the analog 3.
Substitution of triazole with methyl, as in 12a, or two- to
three-carbon alkyl chain (12b and 12c), was not conducive
to good inhibition of 5-LO. Substitution of triazole with
a more substituted three-carbon alkyl chain such as an
isopropyl (analog 12d) or a substituted alkyl chain with a less
flexible end, such as 3-methylbut-2-enyl (analog 12e), does
not seem to be favorable for 5-LO inhibition. Substitution
of the triazole with a hexyl chain slightly increases the 5-LO
inhibition. As shown in Figure 5, analog12f, bearing the hexyl
chain, was more active than 12a but equivalent to 8b, the
analog with triazole substituted with phenethyl. Substitution
of the triazole with cyclohexylethyl was very favorable for the
inhibition of 5-LO as shown in Figure 5.
Test compound (1ꢀM)
Figure 4: Inhibition of 5-LO products synthesis by 10a–f in whole
HEK293 cells. Values are the means SEM of three independent
experiments, each performed in quadruplicate; ∗different from
control (diluent) as determined by one-way ANOVA with Dunnett’s
multiple comparison test (ꢂ < 0.05).
and electron-donating substituents were tested as shown in
Figure 4. All analogs were either equivalent to CAPE (1)
and analog 3 or significantly more active than Zileuton (2).
As shown in Figure 4, the substitution of the phenyl in
the para position with methyl, a weak donating substituent,
seems to have a positive impact on 5-LO inhibition which
was increased by almost 20%. e effect of the hydrophobic
substituent seems to be decisive for increasing the inhibition
of 5-LO.
e introduction in the para position of the phenyl
moiety of moderate (-OCH and -F) or even strong (-OH)
3
donating groups appears to have a moderate effect on activity
since the inhibitory activity of 10b–d is equivalent to that of
8b. On the other hand, the substitution of phenyl by weak
electron-withdrawing substituent seems to be very favorable

Journal of Chemistry
5
100
10e is more lipophilic than 12g, the three fluorine atoms
and the aromatic ring may form hydrogen bonds or ꢀ-ꢀ
interactions that could diminish the availability and/or cell
permeability. Furthermore, Van der Waals interaction of the
cyclohexylethyl moiety of 12g seems to be favorable for 5-LO
inhibition as 12g was the best inhibitor and was equipotent to
Zileuton (2).
∗
∗
∗
∗
75
50
∗
∗
2.3. Molecular Docking. All designed and synthesized com-
pounds were docked to 5-LO in this study. From the obtained
docking results, the binding energy was determined for
each ligand as well as hydrogen bonds, interactions, and
coordination (Table 1). Molecular docking was performed on
a modified 5-LO protein (PDB code: 3O8Y).
∗
25
0
Analogs 8b-c, 10a–d, and 12g were almost overlaid with
slight shifs in position for the R group. e catechol group
was positioned near the iron atom and its coordinating
residues while the other extremity of the ligand was located
near the end of the cavity, near His600. is group seems to
have the best classed analogs (Table 1).
As shown in Figure 7, it is interesting to see the prox-
imity/interaction of the cyclohexyl moiety of analog 12g
with several amino acids of the protein, in particular with
Tyr181 Al603 and Asn425. is proximity/interaction can
explain the favorable effect of the presence of this group
observed in the inhibition tests of 5-LO with 12g in HEK293
and PMNL cells (Figures 5 and 6). Comparison of the
results of the modeling of analogs 12g and 8b clearly shows
that hydrophobic interactions and the cyclohexyl flexibility
appear to be crucial for 5-LO inhibition.
Test compound (1ꢀM)
Figure 6: Inhibition of 5-LO products synthesis by analogs 8a-
b, 10a, 10e, and 12g in stimulated human PMNL. Values are the
means SEM of three independent experiments, each performed
in quadruplicate; ∗different from control (diluent) as determined
by one-way ANOVA with Dunnett’s multiple comparison test (ꢂ <
0.05).
Favorable interactions of the cyclohexylethyl moiety can
explain this good activity since the molecule was significantly
more active than Zileuton (2). Analog 12g was also more
active than analogs 12f and 8b having substituted triazole
with hexyl or phenethyl, respectively (Figure 5). e differ-
ence in lipophilicity can not explain this difference since the
estimated Logp of the three molecules (8b, 12f, and 12g) was
very close.
Analogs 8a, 10e-f, and 12e-f differ, in some minor
way, from the previous group. For 10e-f, the catechol was
perpendicular compared to the previous molecules. 12f takes
a more direct route due to its short length.
Analogs 12b–d were overlaid; only the R group differed
slightly. is group has the characteristic of being inverted
compared to the previous molecules, having the catechol
section near the end of the cavity while the R group is near
the iron atom. It does keep the same general overlap even if
inverted. is group seems to have the least stable ligand.
CAPE (1) analogs 3 and 4 differ in their positioning. In
general, they take similar positions to the previous group.
Analog 4, due to its long length, must contort much more
to fit inside the cavity and reaches the furthest it can in both
extremities. It also presents the triazole ring (nitrogen atoms
side) to the iron atom compared to the R group for previous
ligands. CAPE’s (1) shorter length and position make it so that
it cannot reach the iron atom. Analog 3 presents its second
ester to the iron atom instead of presenting a triazole.
Analog 12a was shifed slightly deeper inside the cavity
due to its shorter length, meaning that the R group was placed
near the end of the cavity and the catechol group does not
reach the section of the cavity containing the iron atom. Its
position resembles more Zileuton (2) than the other analogs.
Similarly, both Zileuton (2) enantiomers occupy the end of
the cavity and do not reach the iron containing section of the
cavity.
2.2.2. Inhibition of 5-LO Products in Simulated Human PMNL.
To further probe inhibitory activity of lead compounds
selected from preliminary HEK293 screenings (Figures 3, 4,
and 5), 5-LO inhibition assays were undertaken in stimulated
human PMNL in the presence of 1 ꢁM of inhibitors. 5-LO
is highly expressed in PMNL and these cells are important
physiological producers of LTB [11, 18].
4
As shown in Figure 6, analogs 8a and 8b having a triazole
substituted by benzyl or ethynylphenyl were less active than
CAPE (1) but were equivalent to Zileuton (2) and analog 3.
Bearing an ethenylcyclohexyl-substituted triazole, 12g was
the best inhibitor of the selected molecules. 12g was more
active than its analogs 3, 10a, and 10b which have methyl- or
trifluoromethyl-substituted triazole, respectively.
Analog 12g was also equivalent to Zileuton (2) but
remains less active than CAPE (1); the favorable effect of
the presence of the cyclohexylethyl moiety seems to be
confirmed in the PMNL test. e difference in inhibitory
activity of our molecules in HEK293 cells and in stimulated
human PMNL may reflect the availability or cell permeation
of our inhibitors. e substitution of the terminal phenyl
group in CAPE (1) with monosubstituted triazoles leads
to a loss of activity in PMNL at 1ꢁM. Moreover, while
In most cases, the tested ligands seem to fill most of the
cavity. 12a seems to leave a slightly more open space than the

6
Journal of Chemistry
Coordination
Table 1: Molecular modeling data∗.
Affinity
Molecule
Hydrogen bonds
ꢀ-ꢀ interactions
His367, Phe421
His367, Phe421
His372
(kcal/mol)
10e
10c
CAPE (1)
8b
8c
4 [17]
10f
10a
12g
12a
10d
8a
10b
12b
12d
12e
Asn554
—
—
—
—
—
Leu607
—
—
—
Ile673
Tyr181
—
—
—
Tyr181
—
—
Phe177, His367 × 2
His367, Phe421
His372
Fe2 × 2
Fe2
—
−9.1
−8.6
−8.5
−8.4
−8.4
−8.4
−8.4
−8.4
−8.4
−8.3
−8.2
−8.1
−8.1
−8.0
−8.0
−8.0
−7.9
−7.9
−7.6
−6.6
−6.5
Fe2
Fe2
Fe2 × 2
Fe2 × 2
Fe2
Fe2
—
Phe177, His367 × 2
His367, Phe421
His367, Phe421
His372
His367, Phe421
His600
Fe2
Fe2
Fe2
—
—
—
Fe2
—
Fe2
—
His367, Phe421
His367, Phe421
His367
Phe421
12f
12c
Phe177, His367
His367, Phe421
Phe177
3 [15]
(R)-Zileuton (2)
(S)-Zileuton (2)
—
Leu420 × 2
Phe421
—
—
—
∗
Molecular docking was performed on a modified 5-LO protein (PDB code: 3O8Y). Figure 7 showing the double bond in “ꢀ”-form is a result of the sofware
used to generate the 2D image, LigPlot. e file given by the molecular docking sofware has the “ꢁ”-form conserved.
others while analog 4 seems to fill the cavity particularly well.
Zileuton (2) fills the end of the cavity while leaving the area
near the iron atom open due to its shorter length.
stimulated human PMNL cells. Analog 12g, bearing an
ethenylcyclohexyl-substituted triazole, was the best inhibitor
of all the series. Analog 12g was also equipotent to Zileuton
(2) but remains less active than CAPE (1). e favorable effect
of the presence of the cyclohexylethyl moiety seems to be con-
firmed in the PMNL test. Hydrophobic interactions appear to
be crucial for good inhibition of 5-LO as shown by compound
12g. Overall, this work highlights novel compounds with
interesting properties against 5-LO and further exemplifies
the likely importance of exploring the impact of polyphenolic
compounds as leukotriene biosynthesis inhibitors.
In agreement with what was previously said, Zileuton
(2) and the first series have similar affinity, with the first
series being favored compared to Zileuton (2). For the second
series, the tendency seems to also agree except for 10c and 10f
being slightly more stable than what would be expected when
compared to the inhibitory potential. For the third series,
the results seem to differ more than the previous series. For
analog 12g and to some extent 12f, the affinity seems to be less
stable than what would be expected.
When looking at the interactions made by the most stable
ligands or that have the strongest measured inhibition, it
seems that a ꢀ-ꢀ interaction with either His367 or His372 is
helpful. Both are iron coordinating residues [19]. It also seems
that not doing a metal coordination with the iron atom is
detrimental to both its affinity and measured activity.
4. Experimental Section
4.1. Methods and Materials. All chemicals used were pur-
chased from Aldrich (CA). Purification of compounds was
carried out by flash chromatography (CombiFlash5, Sep-
aration System SG 100C, ISCO) or by silica gel circu-
lar chromatography (chromatotron5, model 7924, Harrison
Research). TLC was run on silica gel coated aluminum
sheets (SiliaPlate TLC, Silicycle5) with detection by UV
light (254 nm, UVS-11, Mineralight5 shortwave UV lamp).
Melting points were obtained using a MELTEMP (model
1001D) melting point apparatus. FTIR spectra were recorded
on a Cary 630 FTIR spectrometer equipped with a single
reflection diamond ATR. NMR spectra were recorded on a
Bruker5 Avance III 400 MHz spectrometer. High-resolution
3. Conclusion
Despite its undesirable effects, particularly its hepatotoxicity,
Zileuton is still the only approved 5-LO inhibitor for clinical
use to date. In this study, sixteen new 5-LO inhibitors
derived from CAPE (1) and compound 3, recently reported
by our team, were synthesized, characterized, and tested
for their potential to inhibit 5-LO in both HEK293 and

Journal of Chemistry
7
Phe177
Fe21
His367
Ile673
His372
Leu368
Ile415
2.91
Leu414
Asn554
Gln363
Ala410
Asn425
Leu607
Phe421
2.02
2.01
Tyr181
2.81
Ala603
2.52
3.30
2.47
Leu420
Ala424
Trp599
Figure 7: Molecular docking results of 12g displayed in LigPlot.
mass measurements were performed on a Bruker Daltonics’
micrOTOF instrument in positive or negative electrospray.
2H, Har), 6.79–6.77 (m, 1H, Har), 6.33–6.29 (d, 1H, J = 15.9 Hz,
=CHCO), 4.80–4.79 (d, 2H, ꢅ = 2.44 Hz, OCH C), 3.55–3.54
2
(t, 1H, ꢅ = 1.80 Hz, CCH); 13C NMR (100 MHz, DMSO-d ,
6
25∘C), ꢄ (ppm): 166.23, 149.14, 146.61, 146.05, 125.82, 122.15,
116.20, 115.39, 113.40, 79.21, 77.97, 51.93; HRMS m/s calc. for
C H O + (H+): 219.0652; found: 219.0651.
2-Propynyl (E)-3-(3,4-dihydroxyphenyl)acrylate 6. To a solu-
tion of caffeic acid (1 g, 5.61 mmol) in 5 ml of hexam-
ethylphosphoramide (HMPA) under argon atmosphere 1.2
equivalent of Na CO (698.5 mg, 6.59 mmol) is added and
12 10
4
2
3
the solution is stirred at 0∘C for an hour. en a solution of
propargyl bromide in 1 ml of HMPA is added to the solution
in a span of 30 min. A catalytic amount of KI is added to the
solution and the mixture was stirred overnight. e reaction
mixture is then poured in ice. e solution is extracted 3 times
by ethyl acetate; then the aqueous phase is neutralized by a
solution of HCl 1 M and extracted one last time with EtOAc.
e combined organic phase is washed three times with
4.1.1. General Procedure for the Preparation Compounds
8a–8c, 10a–10f, and 12b–12h. To a solution of the appro-
priate halide (7a–c, 9a–f or 11b–h) in 2 ml of DMSO NaN
3
is added and the solution was stirred overnight. en, 6,
CuSO ⋅5H O (0.2 eq), sodium ascorbate (0.10 eq), and 2 ml
4
2
of distilled water are added to the solution and the solution
was stirred overnight. e solution is diluted in water and
the mixture is extracted 3 times with EtOAc. e combined
brine, dried with MgSO , and concentrated under vacuum
4
organic phase is washed twice with a solution of NH Cl
4
to afford the crude product. Compound 6 was obtained
as a white solid is obtained afer flash chromatography
(EtOAc/Hexane 20 : 80). Yield: 528 mg (43%); ꢃꢂ = 0.57
5 M and then twice with brine. e combined organic phase
is dried with MgSO , to afford the crude product. e
4
purification was performed as stated for each compound.
(EtOAc/hexane 50 : 50); m.p. = 133–135∘C; IR (] (cm−1)):
3503–3479 (CarO-H), 3270 (Csp-H), 2100 (C≡C), 1683 (C=O),
(1-Benzyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydrox-
1
1629–1440 (C=C), 1290, 1162 (C-O); H NMR (400 MHz,
yphenyl)acrylate 8a. Benzyl bromide (7a) (54.43 ꢁl,
DMSO-d , 25∘C), ꢄ (ppm): 9.66 (s, 1H, CarOH), 9.18 (s, 1H,
0.46 mmol), NaN (33.61 mg, 0.52 mmol), 6 (118.59 mg,
6
3
CarOH), 7.55–7.51 (d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.08–7.02 (m,
0.54 mmol), CuSO ⋅5H O (53.59 mg, 0.21 mmol), and
4
2

8
Journal of Chemistry
sodium ascorbate (10.38 mg, 0.052 mmol). A beige solid is
obtained afer flash chromatography (EtOAc/hexane 50 : 50).
Yield: 79.4 mg (42%); ꢃꢂ = 0.14 (EtOAc/hexane 50 : 50);
(154.02 mg, 0.71 mmol), CuSO ⋅5H O (38.42 mg, 0.15 mmol),
4
2
and sodium ascorbate (15.49 mg, 0.08 mmol). A beige solid
is obtained afer flash chromatography (EtOAc/hexane
50 : 50). Yield: 173.8 mg (65%); ꢃꢂ = 0.13 (EtOAc/hexane
m.p. = 152-153∘C; IR (] (cm−1)): 3300–3000 (CarO-H), 1687
(C=O), 1630–1443 (C=C), 1280, 1179 (C-O); 1H NMR
50 : 50); m.p. = 123–126∘C; IR (] (cm−1)): 3477 (CarO-H),
1
(4000 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.63 (s, 1H, CarOH),
1702 (C=O), 1601–1447 (C=C), 1281, 1160 (C-O); H NMR
6
9.15 (s, 1H, CarOH), 8.24 (s, 1H, =CHN), 7.51–7.48 (d, 1H, ꢅ =
(400 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.64 (s, 1H, CarOH),
6
15.8 Hz, =CHCar), 7.41–7.32 (m, 5H, Har), 7.05–7.00 (m, 2H,
9.18 (s, 1H, CarOH), 8.08 (s, 1H, =CHN), 7.51–7.47 (d, 1H, ꢅ
Har), 6.77–6.75 (m, 1H, Har), 6.30–6.26 (d, 1H, ꢅ = 15.9 Hz,
= 15.9 Hz, =CHCar), 7.06–7.00 (m, 6H, Har), 6.78–6.76 (m,
1H, Har), 6.29–6.25 (d, 1H, ꢅ = 15.9 Hz, =CHCO), 5.20 (s, 2H,
-OCH C), 4.60–4.56 (t, 2H, J = 7.2 Hz, -NCH C), 3.13–3.09
=CHCO), 5.61 (s, 2H, -OCH -), 5.22 (s, 2H, -NCH Car); 13
C
2
2
NMR (100 MHz, DMSO-d , 25∘C), ꢄ (ppm): 166.73, 149.00,
6
2
2
146.18, 146.02, 142.85, 136.42, 129.25, 128.65, 128.50, 125.87,
125.32, 121.99, 116.17, 115.36, 113.88, 57.46, 53.29; HRMS m/s
calc. for C H N O + (H+): 352.1292; found: 352.1289.
(t, 2H, ꢅ = 7.2 Hz, -CH Car), 2.23 (s, 3H, CarCH ); 13C NMR
2
3
3
(100 MHz, DMSO-d , 25∘C), ꢄ (ppm): 166.68, 149.01, 146.12,
6
146.04, 142.37, 136.02, 134.89, 129.43, 129.00, 125.88, 125.20,
122.00, 116.19, 115.29, 113.92, 57.44, 51.01, 35.71, 21.07; HRMS
m/s calc. for C H N O + (H+): 380.1605; found: 380.1623.
19 17
3
4
(1-Phenethyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydrox-
21 22
4
yphenyl)acrylate 8b. (2-Bromoethyl)benzene (7b) (65 ꢁl,
0.48 mmol), NaN (37.97 mg, 0.58 mmol), 6 (107.76 mg,
{1-[2-(p-Methoxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methyl
3
0.49 mmol), CuSO ⋅5H O (45 mg, 0.18 mmol), and sodium
(E)-3-(3,4-dihydroxyphenyl) acrylate 10b. p-(2-Bromoeth-
4
2
ascorbate (16.20 mg, 0.082 mmol). A beige solid is obtained
afer flash chromatography (EtOAc/hexane 50 : 50). Yield:
102.4 mg (57%); ꢃꢂ = 0.12 (EtOAc/hexane 50 : 50); m.p. =
yl)methoxybenzene (9b) (108 ꢁl, 0.69 mmol), NaN
3
(49.77 mg, 0.77 mmol), 6 (150.38 mg, 0.69 mmol), CuSO ⋅
4
5H O (36.85 mg, 0.15 mmol), and sodium ascorbate
2
108–110∘C; IR (] (cm−1)): 3300–3000 (CarO-H), 1693 (C=O),
(16.17 mg, 0.082 mmol). A white solid is obtained afer flash
chromatography (EtOAc/hexane 60 : 40). Yield: 176.2 mg
(65%); ꢃꢂ = 0.09 (EtOAc/hexane 50 : 50); m.p. = 153-154∘C;
1
1598–1450 (C=C), 1280, 1153 (C-O); H NMR (400 MHz,
DMSO-d , 25∘C), ꢄ (ppm): 9.36 (s, 1H, CarOH), 9.19 (s,
6
IR (] (cm−1)): 3471 (CarO-H), 1700 (C=O), 1620–1440
1H, CarOH), 8.10 (s, 1H, =CHN), 7.51–7.47 (d, 1H, ꢅ =
15.9 Hz, =CHCar), 7.29–7.19 (m, 5H, Har), 7.06–7.00 (m, 2H,
Har), 6.78–6.76 (m, 1H, Har), 6.29–6.25 (d, 1H, ꢅ = 15.9 Hz,
(C=C), 1280, 1250, 1160 (C-O); 1H NMR (400 MHz, DMSO-
d , 25∘C), ꢄ (ppm): 9.62 (s, 1H, CarOH), 9.15 (s, 1H, CarOH),
6
=CHCO), 5.20 (s, 2H, -OCH C), 4.64–4.60 (t, 2H, ꢅ = 7.2 Hz,
8.09 (s, 1H, =CHN), 7.52–7.48 (d, 1H, ꢅ = 15.9 Hz, =CHCar),
2
-NCH C), 3.18–3.15 (t, 2H, ꢅ = 7.2 Hz, -CH Car); 13C NMR
7. 11–7. 00 (m, 4H, Har), 6.84–6.76 (m, 3H, Har), 6.30–6.26 (d,
2
2
(100 MHz, DMSO-d , 25∘C), ꢄ (ppm): 166.68, 149.01, 146.13,
1H, J = 15.9 Hz, =CHCO), 5.20 (s, 2H, OCH C=), 4.59–4.55
6
2
146.04, 142.38, 138.04, 129.14, 128.87, 127.04, 125.88, 125.20,
121.97, 116.19, 115.34, 113.93, 57.45, 50.90, 36.13; HRMS m/s calc.
for C H N O + (H+): 366.1448; found: 366.1454.
(t, 2H, ꢅ = 7.2 Hz, NCH C), 3.69 (s, 3H, OCH ), 3.11–3.07
2
3
(t, 2H, ꢅ = 7.2 Hz, -CH Car); 13C NMR (100 MHz, DMSO-
2
d , 25∘C), ꢄ (ppm): 166.68, 158.43, 149.01, 146.13, 146.04,
19 17
3
4
6
142.36, 130.16, 129.83, 125.88, 125.18, 121.98, 116.18, 115.34,
114.27, 113.92, 57.46, 55.41, 51.18, 35.29; HRMS m/s calc. for
C H N O + (H+): 396.1554; found: 396.1530.
[1-(3-Phenylpropyl)-1H-1,2,3-triazol-4-yl]methyl (E)-3-(3,4
dihydroxyphenyl) acrylate 8c. 1-Bromo-3-phenylpropane
19 17
3
4
(7c) (72 ꢁl, 0.47 mmol), NaN (40.66 mg, 0.63 mmol),
3
6
(100.18 mg, 0.46 mmol), CuSO ⋅5H O (60.94 mg,
4
2
{1-[2-(p-Fluorophenyl)ethyl]-1H-1,2,3-triazol-4-yl}methyl (E)-
0.24 mmol), and sodium ascorbate (10.66 mg, 0.054 mmol).
A beige solid is obtained afer flash chromatography
(EtOAc/hexane 50 : 50). Yield: 92.9 mg (53%); ꢃꢂ = 0.12
3-(3,4-dihydroxyphenyl) acrylate 10c. p-(2-Bromoethyl)flu-
orobenzene (9c) (144.41 ꢁl, 1.03 mmol), NaN (70.05 mg,
3
1.08 mmol),
6
(151.17 mg, 0.69 mmol), CuSO ⋅5H O
4
2
(EtOAc/hexane 50 : 50); m.p. = 122–125∘C; IR (] (cm−1)):
(45.65 mg, 0.18 mmol), and sodium ascorbate (16.07 mg,
0.08 mmol). A pale yellow solid is obtained afer flash
chromatography (EtOAc/hexane 50 : 50). Yield: 168.0 mg
(63%); ꢃꢂ = 0.11 (EtOAc/hexane 50 : 50); m.p. = 48–53∘C; IR
3486, 3309 (CarO-H), 1685 (C=O), 1603–1450 (C=C), 1277,
1169 (C-O); 1H NMR (400 MHz, DMSO-d , 25∘C), ꢄ (ppm):
6
9.63 (s, 1H, CarOH), 9.17 (s, 1H, CarOH), 8.22 (s, 1H, =CHN),
7. 53–7. 49 (d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.31–7.18 (m, 5H, Har),
7. 06–7. 0 0 (m, 2H, Har), 6.77–6.75 (m, 1H, Har), 6.31–6.27 (d,
(] (cm−1)): 3300–3000 (CarO-H), 1702 (C=O), 1600–1440
1
(C=C), 1220, 1151 (C-O), 1210 (C-F); H NMR (400 MHz,
1H ꢅ = 15.9 Hz, =CHCO), 5.24 (s, 2H, OCH C=), 4.40–4.36
DMSO-d , 25∘C), ꢄ (ppm): 9.26 (m, 3H, CarOH), 8.09 (s, 1H,
2
6
(t, 2H, ꢅ = 7.1 Hz, NCH -), 2.59–2.55 (t, 2H ꢅ = 7.4 Hz,
2
-CH Car), 2.18–2.12 (quint, 2H, J = 7.4 Hz, -CH -); 13C NMR
=CHN), 7.52–7.48 (d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.06–6.97
(m, 4H, Har), 6.78–6.76 (m, 1H, Har), 6.67–6.65 (m, 2H,
Har), 6.30–6.26 (d, 1H, J = 15.9 Hz, =CHCO), 5.20 (s, 2H,
-OCH C), 4.55–4.52 (t, 2H, ꢅ = 7.3 Hz, NCH C), 3.05–3.02
2
2
(100 MHz, DMSO-d , 25∘C), ꢄ (ppm): 166.74, 149.01, 146.15,
6
146.04, 142.58, 141.18, 128.86, 128.78, 126.47, 125.88, 125.12,
122.00, 116.18, 115.32, 113.92, 57.51, 49.40, 32.32, 31.75; HRMS
m/s calc. for C H N O + (H+): 380.1605; found: 380.1622.
2
2
(t, 2H, J = 7.3 Hz, -CH Car); 13C NMR (100 MHz, DMSO-d ,
2
6
19 17
3
4
25∘C), ꢄ (ppm): 166.71, 156.44, 149.00, 146.13, 146.03, 142.33,
130.07, 128.01, 125.88, 125.14, 122.01, 116.19115.66, 115.30, 113.92,
57.47, 51.30, 35.41; HRMS m/s calc. for C H N O + (H+):
{1-[2-(p-Tolyl)ethyl]-1H-1,2,3-triazol-4-yl}methyl (E)-3-(3,4-
dihydroxyphenyl) acrylate 10a. p-(2-Bromoethyl)toluene
20 19
3
4
(9a) (157.18 ꢁl, 1.03 mmol), NaN (75.92 mg, 1.16 mmol), 6
384.1354; found: 384.1375.
3

Journal of Chemistry
9
{1-[2-(p-Tolyl)ethyl]-1H-1,2,3-triazol-4-yl}methyl (E)-3-(3,4-
dihydroxyphenyl) acrylate 10d. p-(2-Bromoethyl)phenol (9d)
-OCH C), 4.71–4.68 (t, 2H, ꢅ = 7.2 Hz, NCH C), 3.33–3.31 (t,
2
2
2H, ꢅ = 7.2 Hz, -CCH Car); 13C NMR (100 MHz, DMSO-d ,
2
6
(212.59 mg, 1.06 mmol), NaN (78.20 mg, 1.20 mmol),
25∘C), ꢄ (ppm): 166.67, 149.02, 146.84, 146.39, 146.16, 146.04,
142.52, 130.56, 125.87, 125.30, 123.90, 121.97, 116.18, 115.35,
113.86, 57.43, 50.17, 35.73; HRMS m/s calc. for C H N O +
3
6
(156.05 mg, 0.72 mmol), CuSO ⋅5H O (42.50 mg,
4
2
0.17 mmol), and sodium ascorbate (20.41 mg, 0.11 mmol). A
white solid is obtained afer flash chromatography (EtOAc/
hexane 70 : 30). Yield = 129.4 mg (47%); ꢃꢂ = 0.19 (EtOAc/
19 17
3
4
(H+): 411.1299; found: 411.1276.
hexane 70 : 30); m.p. = 70–75∘C; IR (] (cm−1)): 3400–3000
(1-Methyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydroxy-
phenyl)acrylate 12a. A solution of iodomethane (11a)
(CarO-H), 2922 (Csp3-H), 1687 (C=O), 1598–1440 (C=C),
(64.19 ꢁl, 1.03 mmol), NaN (72.03 mg, 1.11 mmol), 6
1270, 1230, 1156 (C-O); 1H NMR (400 MHz, DMSO-d ,
3
6
(154.45 mg, 0.71 mmol), and copper iodine (27.87 mg,
0.15 mmol) in 5 ml of a mixture of water and acetone (1 : 1)
was placed in an ultrasound bath and was lef to react under
ultrasound at room temperature overnight. e solution was
then extracted 3 times with EtOAc. e combined organic
25∘C), ꢄ (ppm): 9.26 (m, 3H, CarOH), 8.09 (s, 1H, =CHN),
7. 52–7. 4 8 (d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.06–6.97 (m, 4H, Har),
6.78–6.76 (m, 1H, Har), 6.67–6.65 (m, 2H, Har), 6.30–6.26 (d,
1H, J = 15.9 Hz, =CHCO), 5.20 (s, 2H, -OCH C), 4.55–4.52
2
(t, 2H, ꢅ = 7.3 Hz, NCH C), 3.05–3.02 (t, 2H, ꢅ = 7.3 Hz,
2
phases are washed twice with a solution of NH Cl 5 M and
-CH Car); 13C NMR (100 MHz, DMSO-d , 25∘C), ꢄ (ppm):
4
2
6
then twice with brine. e combined organic phase is dried
166.71, 156.44, 149.00, 146.13, 146.03, 142.33, 130.07, 128.01,
125.88, 125.14, 122.01, 116.19, 115.66, 115.30, 113.92, 57.47, 51.30,
35.41; HRMS m/s calc. for C H N O + (H+): 382.1397;
with MgSO and concentrated under vacuum to afford
4
the crude product. Compound 12a was obtained as brown
solid afer flash chromatography (EtOAc/Hexane 70 : 30).
Yield = 45.9 mg (24%); ꢃꢂ = 0.14 (EtOAc/hexane 70 : 30);
20 20
3
5
found: 382.1392.
m.p. = 49–55∘C; IR (] (cm−1)): 3400–3000 (CarO-H), 2922
(1-{2-[p-(Trifluoromethyl)phenyl]ethyl}-1H-1,2,3-triazol-4-
yl)methyl (E)-3-(3,4-dihydroxyphenyl)acrylate 10e. p-(2-Bro-
moethyl)(trifluoromethyl)benzene (9e) (120 ꢁl, 0.71 mmol),
(Csp3-H), 1696 (C=O), 1598–1440 (C=C), 1251, 1147 (C-O);
1H NMR (400 MHz, CD OD, 25∘C), ꢄ (ppm): 8.00 (s, 1H,
3
NaN (49.71 mg, 0.77 mmol), 6 (153.03 mg, 0.70 mmol),
=CHN), 7.61–7.57 (d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.04–6.94
(m, 2H, Har), 6.80–6.78 (m, 1H, Har), 6.29–6.25 (d, 1H, ꢅ =
15.9 Hz, =CHCO), 5.29 (s, 2H, -OCH C), 4.13 (s, 3H, NCH );
3
CuSO ⋅5H O (40.57 mg, 0.16 mmol), and sodium ascorbate
4
2
(15.18 mg, 0.077 mmol). A white solid is obtained afer flash
chromatography (EtOAc/hexane 55 : 45). Yield: 205.6 mg
(68%); ꢃꢂ = 0.10 (EtOAc/hexane 50 : 50); m.p. = 150-151∘C;
2
3
13C NMR (100 MHz, CD OD, 25∘C), ꢄ (ppm): 167.24, 148.33,
3
146.09, 145.43, 142.98, 126.20, 125.32, 121.65, 115.09, 113.73,
113.12, 56.66, 35.62; HRMS m/s calc. for C H N O + (H+):
IR (] (cm−1)): 3400–3000 (CarO-H), 1695 (C=O), 1600–1440
13 13
3
4
1
276.0979; found: 276.0997.
(C=C), 1270, 1156 (C-O), 1220 (C-F); H NMR (400 MHz,
DMSO-d , 25∘C), ꢄ (ppm): 9.67 (s, 1H, CarOH), 9.19 (s, 1H,
6
(1-Ethyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydroxy-
CarOH), 8.15 (s, 1H, =CHN), 7.64–7.63 (m, 2H, Har), 7.52–7.48
(d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.43–7.41 (m, 2H, Har), 7.06–7.00
(m, 2H, Har), 6.78–6.76 (m, 1H, Har), 6.29–6.26 (d, 1H, ꢅ =
phenyl)acrylate 12b. Bromoethane (11b) (80 ꢁl, 1.08 mmol),
NaN (61.01 mg, 0.88 mmol), 6 (148.72 mg, 0.68 mmol),
3
CuSO ⋅5H O (41.62 mg, 0.17 mmol), and sodium ascor-
4
2
15.9 Hz, =CHCO), 5.20 (s, 2H, -OCH C), 4.69–4.65 (t, 2H, ꢅ
2
bate (20.94 mg, 0.11 mmol). A beige solid is obtained afer
flash chromatography (EtOAc/hexane 70 : 30). Yield: 127.5 mg
(59%); ꢃꢂ = 0.19 (EtOAc/hexane 70 : 30); m.p. = 188–191∘C; IR
= 7.2 Hz, NCH C), 3.29–3.26 (t, 2H, ꢅ = 7.2 Hz, -CCH Car);
2
2
13C NMR (100 MHz, DMSO-d , 25∘C), ꢄ (ppm): 166.68,
6
149.01, 146.16, 146.03, 143.05, 142.49, 130.04, 125.86, 125.67,
125.64, 125.28, 121.97, 116.16, 115.32, 113.86, 57.43, 55.37, 50.40,
35.77; HRMS m/s calc. for C H N O + (H+): 434.1322;
(] (cm−1)): 3400–3000 (CarO-H), 2924 (Csp3-H), 1687 (C=O),
1
1596–1440 (C=C), 1257, 1147 (C-O); H NMR (400 MHz,
19 17
3
4
DMSO-d , 25∘C), ꢄ (ppm): 9.62 (s, 1H, CarOH), 9.19 (s, 1H,
found: 434.1314.
6
CarOH), 8.19 (s, 1H, =CHN), 7.52–7.48 (d, 1H, ꢅ = 15.9 Hz,
{1-[2-(p-Nitrophenyl)ethyl]-1H-1,2,3-triazol-4-yl}methyl (E)-
=CHCar), 7.05–7.00 (m, 2H, Har), 6.77–6.75 (m, 1H, Har),
3-(3,4-dihydroxy-phenyl) acrylate 10f . p-(2-Bromoeth-
6.30–6.26 (d, 1H, J = 15.9 Hz, =CHCO), 5.22 (s, 2H, -OCH C),
2
yl)nitrobenzene (9f) (161.25 mg, 0.70 mmol), NaN
3
4.42–4.36 (q, 2H, ꢅ = 7.3 Hz, -CH C), 1.45–1.41 (t, 3H, ꢅ
2
(46.81 mg, 0.72 mmol), 6 (149.83 mg, 0.69 mmol), CuSO ⋅
= 7.3 Hz, -CH ); 13C NMR (100 MHz, DMSO-d , 25∘C), ꢄ
4
3
6
5H O (40.68 mg, 0.16 mmol), and sodium ascorbate
2
(ppm): 166.74, 149.00, 146.15, 146.03, 142.51, 125.87, 124.63,
122.00, 116.18, 115.30, 113.91, 57.50, 45.06, 15.82; HRMS m/s
calc. for C H N O + (H+): 320.0877; found: 320.0874.
(23.51 mg, 0.12 mmol). A yellow solid is obtained afer flash
chromatography (EtOAc/hexane 70 : 30). Yield = 149.7 mg
(53%); ꢃꢂ = 0.19 (EtOAc/hexane 7 : 3); m.p. = 159–161∘C;
19 17
3
4
IR (] (cm−1)): 3445 (CarO-H), 2920 (Csp3-H), 1719 (C=O),
(1-Propyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydroxy-
1
phenyl)acrylate 12c. 1-Bromopropane (11c) (88.43 ꢁl,
1603–1440 (C=C), 1520, 1340 (NO ), 1255, 1151 (C-O); H
2
NMR (400 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.64 (s, 1H,
3
1.03 mmol), NaN (67.37 mg, 1.04 mmol), 6 (155.09 mg,
6
0.71 mmol), CuSO ⋅5H O (44.51 mg, 0.18 mmol), and
CarOH), 9.17 (s, 1H, CarOH), 8.14 (s, 1H, =CHN), 8.12–8.11
(m, 2H, Har), 7.51–7.47 (d, 1H, ꢅ = 15.9 Hz, =CHCar), 7.49
(m, 2H, Har), 7.05–6.99 (m, 2H, Har), 6.77–6.75 (m, 1H,
Har), 6.28–6.24 (d, 1H, ꢅ = 15.9 Hz, =CHCO), 5.19 (s, 2H,
4
2
sodium ascorbate (23.50 mg, 0.12 mmol). A darker beige
solid is obtained afer flash chromatography (EtOAc/hexane
50 : 50). Yield: 118.7 mg (55%); ꢃꢂ = 0.11 (EtOAc/hexane

10
Journal of Chemistry
50 : 50); m.p. = 45–50∘C; IR (] (cm−1)): 3334 (CarO-H), 2926
chromatography (EtOAc/hexane 40 : 60). Yield: 53.6 mg
(22%); ꢃꢂ = 0.20 (EtOAc/hexane 50 : 50); m.p. = 51–55∘C;
(Csp3-H), 1687 (C=O), 1605–1440 (C=C), 1274, 1150 (C-O);
1H NMR (400 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.62 (s, 1H,
IR (] (cm−1)): 3500–3000 (CarO-H), 2924, 2855 (Csp3-H),
6
1
CarOH), 9.14 (s, 1H, CarOH), 8.18 (s, 1H, =CHN), 7.53–7.49 (d,
1H, J = 15.9 Hz, =CHCar), 7.05–7.00 (m, 2H, Har), 6.77–6.75
(m, 1H, Har), 6.30–6.26 (d, 1H, J = 15.9 Hz, =CHCO), 5.23
(s, 2H, -OCH C), 4.34–4.31 (t, 2H, J = 7.0 Hz, NCH C),
1702 (C=O), 1598–1440 (C=C), 1257, 1149 (C-O); H NMR
(400 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.63 (s, 1H, CarOH),
6
9.17 (s, 1H, CarOH), 8.18 (s, 1H, =CHN), 7.52–7.48 (d, 1H, ꢅ
= 15.9 Hz, =CHCar), 7.05–6.99 (m, 2H, Har), 6.78–6.72 (m,
1H, Har), 6.31–6.26 (d, 1H, J = 15.9 Hz, =CHCO), 5.22 (s, 2H,
-OCH C), 4.37–4.33 (t, 2H, ꢅ = 7.1 Hz, NCH C), 1.84–177
2
2
1.88–1.79 (sext, 2H, ꢅ = 7.2 Hz, -CH C), 0.87–0.83 (t, 3H, J
2
= 7.4 Hz, -CH ); 13C NMR (100 MHz, DMSO-d , 25∘C), ꢄ
3
6
2
2
(ppm): 166.73, 149.00, 146.15, 146.03, 142.46, 125.88, 125.08,
121.97, 116.18, 115.35, 113.92, 57.51, 51.40, 23.61, 11.27; HRMS
m/s calc. for C H N O + (H+): 304.1292; found: 304.1291.
(quint, 2H, J = 7.2 Hz, CCH C), 1.25–1.21 (m, 6H, Hsp3),
2
0.86–0.83 (t, 3H, ꢅ = 6.7 Hz, -CCH ); 13C NMR (100 MHz,
3
15 17
3
4
DMSO-d , 25∘C), ꢄ (ppm): 166.73, 149.00, 146.14, 146.03,
6
(1-Isopropyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydrox-
142.46, 125.87, 125.07, 121.99, 116.18, 115.30, 113.92, 57.50,
49.82, 31.00, 30.08, 25.93, 22.36, 14.28; HRMS m/s calc. for
C H N O + (H+): 346.1761; found: 346.1764.
yphenyl)acrylate 12d. 2-Bromopropane (11d) (96.81 ꢁl,
1.03 mmol), NaN (72.32 mg, 1.11 mmol), 6 (155.78 mg,
3
19 17
3
4
0.71 mmol), CuSO ⋅5H O (57.31 mg, 0.23 mmol), and
4
2
sodium ascorbate (19.14 mg, 0.10 mmol). A white solid is
obtained afer flash chromatography (EtOAc/hexane 50 : 50).
Yield: 117.3 mg (54%); ꢃꢂ = 0.11 (EtOAc/hexane 50 : 50); m.p.
[1-(2-Cyclohexylethyl)-1H-1,2,3-triazol-4-yl]methyl (E)-3-(3,4-
dihydroxy phenyl) acrylate 12g. 1-(2-Bromoethyl)cyclohexane
(11g) (108 ꢁl, 0.69 mmol), NaN (55.15 mg, 0.85 mmol),
3
= 50–55∘C; IR (] (cm−1)): 3376 (CarO-H), 2930 (Csp3-H),
6
(152.30 mg, 0.70 mmol), CuSO ⋅5H O (59.72 mg,
4
2
1
0.24 mmol), and sodium ascorbate (20.80 mg, 0.10 mmol).
A pale yellow solid is obtained afer flash chromatography
(EtOAc/hexane 40 : 60). Yield = 131.8 mg (51%); ꢃꢂ = 0.19
1693 (C=O), 1633–1440 (C=C), 1285, 1162 (C-O); H NMR
(400 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.61 (s, 1H, CarOH),
6
9.14 (s, 1H, CarOH), 8.24 (s, 1H, =CHN), 7.53–7.49 (d, 1H, ꢅ
= 15.9 Hz, =CHCar), 7.06–7.00 (m, 2H, Har), 6.77–6.75 (m,
1H, Har), 6.31–6.27 (d, 1H, J = 15.9 Hz, =CHCO), 5.22 (s, 2H,
(EtOAc/hexane 50 : 50); m.p. = 66–72∘C; IR (] (cm−1)):
3356 (CarO-H), 2924, 2853 (Csp3-H), 1687 (C=O), 1600–1443
-OCH C), 4.86–4.79 (sept, 1H, ꢅ = 6.6 Hz, NCH-), 1.50–1.49
(C=C), 1292, 1160 (C-O); 1H NMR (400 MHz, CD OD,
2
(d, 6H, ꢅ = 6.7 Hz, -(CH ) ); 13C NMR (100 MHz, DMSO-d ,
3
25∘C), ꢄ (ppm): 8.04 (s, 1H, =CHN), 7.61–7.57 (d, 1H, ꢅ =
3 2
6
25∘C), ꢄ (ppm): 166.73, 149.00, 146.16, 146.03, 142.34, 125.89,
123.02, 121.97, 116.18, 115.37, 113.92, 57.55, 52.83, 23.08; HRMS
m/s calc. for C H N O + (H+): 304.1292; found: 304.1334.
15.9 Hz, =CHCar), 7.05–6.78 (m, 3H, Har), 6.30–6.23 (d, 1H,
J = 15.9 Hz, =CHCO), 5.30 (s, 2H, OCH C=), 4.47–4.43 (t,
2
2H, ꢅ = 7.4 Hz, NCH C), 2.03–1.01 (m, 13H, Hsp3); 13C NMR
15 17
3
4
2
(100 MHz, CD OD, 25∘C), ꢄ (ppm): 167.26, 148.33, 146.10,
3
[1-(3-Methyl-2-butenyl)-1H-1,2,3-triazol-4-yl]methyl (E)-3-(3,
145.43, 142.81, 126.21, 124.28, 121.66, 115.09, 113.75, 113.15,
56.73, 47.93, 37.31, 34.77, 32.54, 26.08, 25.81; HRMS m/s calc.
for C H N O + (H+): 372.1918; found: 372.1922.
4-dihydroxy phenyl) acrylate 12e. 1-Bromo-3-methyl-2-butene
(11e) (95.30 ꢁl, 0.82 mmol), NaN (79.84 mg, 1.23 mmol), 6
3
19 17
3
4
(153.88 mg, 0.71 mmol), CuSO ⋅5H O (46.63 mg, 0.19 mmol),
4
2
and sodium ascorbate (18.40 mg, 0.09 mmol). A dark beige
solid is obtained afer flash chromatography (EtOAc/hexane
40 : 60). Yield: 147.1 mg (63%); ꢃꢂ = 0.18 (EtOAc/hexane
4.2. 5-LO Product Biosynthesis Inhibition Assays
4.2.1. 5-LO Products Biosynthesis Inhibition in HEK293 Cells.
HEK293 cells stably cotransfected with a pcDNA3.1 vector
expressing human 5-LO and a pBUDCE4.1 vector expressing
human 5-LO activating protein (FLAP) were utilized [15, 20]
to screen compounds for 5-LO inhibition.
50 : 50); m.p. = 123–126∘C; IR (] (cm−1)): 3460 (CarO-H),
2969 (Csp3-H), 1702 (C=O), 1603–1440 (C=C), 1264, 1153 (C-
O); H NMR (400 MHz, DMSO-d , 25∘C), ꢄ (ppm): 9.62
1
6
(s, 1H, CarOH), 9.14 (s, 1H, CarOH), 8.10 (s, 1H, =CHN),
7. 52–7. 4 8 (d, 1H, J = 15.9 Hz, =CHCar), 7.05–7.00 (m, 2H,
Har), 6.77–6.75 (m, 1H, Har), 6.30–6.26 (d, 1H, J = 15.9 Hz,
For cell stimulation of 5-LO products, transfected
HEK293 cells were collected following trypsinization and
washed and the cell pellet was resuspended in Hank’s bal-
anced salt solution (HBSS) (Lonza, Walkerville, MD) con-
=CHCO), 5.43–5.40 (m, 1H, -CHC(CH ) ), 5.22 (s, 2H,
3 2
-OCH C), 4.99–4.97 (d, 2H, J = 7.3 Hz, NCH -), 1.77–1.74 (d,
2
2
taining 1.6 mM CaCl at a concentration of 5 × 105 cells mL−1.
6H, J = 13.5 Hz, -C(CH ) ); 13C NMR (100 MHz, DMSO-d ,
2
3 2
6
25∘C), ꢄ (ppm): 166.73, 149.01, 146.15, 146.03, 142.57, 138.63,
125.88, 124.69, 121.98, 118.82, 116.18, 115.35, 113.91, 57.48, 55.28,
47.71, 25.76, 18.30; HRMS m/s calc. for C H N O + (H+):
Cells were preincubated with each test compound at 1 ꢁM
for 5 min at 37∘C. Cells were then stimulated for 15 minutes
at 37∘C with the addition of 10 ꢁM calcium ionophore
A23187 (Sigma-Aldrich, Oakville, ON, Canada) and 10 ꢁM
arachidonic acid (Cayman Chemical, Ann Arbour, MI).
Stimulations were stopped by the addition of 0.5 volume
of cold MeOH : CH CN (1 : 1) containing 50 ng of PGB as
17 20
3
4
330.1448; found: 330.1419.
(1-Hexyl-1H-1,2,3-triazol-4-yl)methyl (E)-3-(3,4-dihydroxy-
phenyl)acrylate 12f . 1-Chlorohexane (11f) (100 ꢁl, 0.73 mmol),
3
2
internal standard and samples were stored at −20∘C until
processing on octadecyl (C18) columns and analysis by RP-
HPLC as described previously [15, 20]. Data are expressed as
NaN (52.12 mg, 0.80 mmol), 6 (155 mg, 0.71 mmol),
3
CuSO ⋅5H O (37.26 mg, 0.15 mmol), and sodium ascorbate
4
2
(15.37 mg, 0.078 mmol). A brown solid is obtained afer flash

Journal of Chemistry
11
means SEM of 3 independent experiments, each performed
in duplicate (Figures 3–5).
[6] E. Israel, J. Cohn, L. Dube´, and J. M. Drazen, “Effect of
treatment with zileuton, a 5-lipoxygenase inhibitor, in patients
with asthma: a randomized controlled trial,” Journal of the
American Medical Association, vol. 275, no. 12, pp. 931–936, 1996.
[7] O. Werz and D. Steinhilber, “erapeutic options for 5-lipoxy-
genase inhibitors,” Pharmacology & erapeutics, vol. 112, no. 3,
pp. 701–718, 2006.
[8] A. S. Fischer, J. Metzner, S. D. Steinbrink et al., “5-Lipoxygenase
inhibitors induce potent anti-proliferative and cytotoxic effects
in human tumour cells independently of suppression of 5-
lipoxygenase activity,” British Journal of Pharmacology, vol. 161,
no. 4, pp. 936–949, 2010.
[9] J. Ghosh and C. E. Myers, “Inhibition of arachidonate 5-
lipoxygenase triggers massive apoptosis in human prostate
cancer cells,” Proceedings of the National Academy of Sciences
of the United States of America, vol. 95, no. 22, pp. 13182–13187,
1998.
4.2.2. 5-LO Products Biosynthesis Inhibition in PMNL Cells
PMNL. Human PMNL prepared from peripheral blood as
described [11] were suspended in HBSS containing 1.6 mM
CaCl (107 cells/ml) and preincubated with test compounds
2
for 5 min at 37∘C in the presence of 0.4 U/ml of adenosine
deaminase (Sigma-Aldrich, Oakville, On, Canada). Cells
were then stimulated for 15 min at 37∘C with 1 ꢁM thapsi-
gargin (Sigma-Aldrich) and 10 ꢁM AA (Cayman Chemical,
Ann Arbour, MI) as previously described [11]. Reactions were
stopped, processed, and analyzed by RP-HPLC as indicated
above. Data are expressed as means SEM of 3 independent
experiments, each performed in duplicate (Figure 6).
4.3. Molecular Docking. Molecular docking was performed
with AutoDock Vina 1.1.2 on 5-LO (PDB code: 3O8Y) fol-
lowing the procedure [17] outlined in “Design, Synthesis and
Evaluation of Semi-Synthetic Triazole-Containing Caffeic
Acid Analogs as 5-Lipoxygenase Inhibitors” by Daniela De
Lucia et al. For optimization, the MMFF94 force field was
used. Results were analyzed with Maestro 11.0 [21].
[10] A.-P. Beauregard, J. Harquail, G. Lassalle-Claux et al., “CAPE
analogs induce growth arrest and apoptosis in breast cancer
cells,” Molecules, vol. 20, no. 7, pp. 12576–12589, 2015.
[11] Je´re´mie A. Doiron, Luc M. Leblanc, Martin J. G. He´bert et al.,
“Structure activity relationship of caffeic acid phenethyl ester
analogs as new 5-lipoxygenase inhibitors,” Chemical Biology &
Drug Design, vol. 89, no. 4, pp. 514–528, 2017.
[12] L. H. Boudreau, J. Maillet, L. M. LeBlanc et al., “Caffeic acid
phenethyl ester and its amide analogue are potent inhibitors of
leukotriene biosynthesis in human polymorphonuclear leuko-
cytes,” PLoS ONE, vol. 7, no. 2, Article ID e31833, 2012.
[13] D. De Lucia, O. M. Lucio, B. Musio et al., “Design, synthesis and
evaluation of semi-synthetic triazole-containing caffeic acid
analogues as 5-lipoxygenase inhibitors,” European Journal of
Medicinal Chemistry, vol. 101, pp. 573–583, 2015.
Conflicts of Interest
e authors declare that there are no conflicts of interest
regarding the publication of this paper.
Acknowledgments
[14] E. M. Joshi, B. H. Heasley, M. D. Chordia, and T. L. Macdonald,
“In vitro metabolism of 2-acetylbenzothiophene: relevance to
zileuton hepatotoxicity,” Chemical Research in Toxicology, vol.
17, no. 2, pp. 137–143, 2004.
[15] L. H. Boudreau, N. Picot, J. Doiron et al., “Caffeoyl and cin-
namoyl clusters with anti-inflammatory and anti-cancer effects.
Synthesis and structure-activity relationship,” New Journal of
Chemistry, vol. 33, no. 9, pp. 1932–1940, 2009.
Mohamed Touaibia would like to acknowledge the contri-
bution of the Natural Sciences and Engineering Research
Council of Canada (NSERC), the New Brunswick Innovation
Foundation (NBIF), the Canadian Foundation for Innova-
tion (CFI), and Universite´ de Moncton. Marc E. Surette is
supported by a New Brunswick Innovation Research Chair
awarded by the NBIF.
[16] J. A. Doiron, B. Me´tayer, R. R. Richard et al., “Clicked
cinnamic/caffeic esters and amides as radical scavengers and
5-lipoxygenase inhibitors,” International Journal of Medicinal
Chemistry, vol. 2014, 12 pages, 2014.
[17] C. E. Walsh, B. M. Waite, M. J. omas, and L. R. DeChatelet,
“Release and metabolism of arachidonic acid in human neu-
trophils,” Journal of Biological Chemistry, vol. 256, no. 14, pp.
7228–7234, 1981.
References
[1] W. R. Henderson Jr., “e role of leukotrienes in inflammation,”
Annals of Internal Medicine, vol. 121, no. 9, pp. 684–697, 1994.
[2] C. Pergola and O. Werz, “5-Lipoxygenase inhibitors: a review of
recent developments and patents,” Expert Opinion on erapeu-
tic Patents, vol. 20, no. 3, pp. 355–375, 2010.
[18]
E. Shang et al., “Benzo[d]isothiazole 1, 1-dioxide derivatives as
dual functional inhibitors of 5-lipoxygenase and microsomal
prostaglandin E2 synthase-1,” Bioorganic & Medicinal Chemistry
Letters, vol. 24, no. 12, pp. 2764–2767, 2014.
[3] O. Kowal-Bielecka, K. Kowal, O. Distler, and S. Gay, “Mech-
anisms of disease: leukotrienes and lipoxins in scleroderma
lung disease—insights and potential therapeutic implications,”
Nature Clinical Practice Rheumatology, vol. 3, no. 1, pp. 43–51,
2007.
[4] J. N. Sharma and L. A. Mohammed, “e role of leukotrienes
in the pathophysiology of inflammatory disorders: is there a
case for revisiting leukotrienes as therapeutic targets?” Inflam-
mopharmacology, vol. 14, no. 1-2, pp. 10–16, 2006.
[5] B. Samuelsson, S.-E. Dahlen, J. A. Lindgren, C. A. Rouzer, and C.
N. Serhan, “Leukotrienes and lipoxins: structures, biosynthesis,
and biological effects,” Science, vol. 237, no. 4819, pp. 1171–1176,
1987.
[19] N. C. Gilbert, S. G. Bartlett, M. T. Waight et al., “e structure of
human 5-lipoxygenase,” Science, vol. 331, no. 6014, pp. 217–219,
2011.
[20] J. Doiron, L. H. Boudreau, N. Picot, B. Villebonet, M. E. Surette,
and M. Touaibia, “Synthesis and 5-lipoxygenase inhibitory
activity of new cinnamoyl and caffeoylclusters,” Bioorganic and
Medicinal Chemistry Letters, vol. 19, no. 4, pp. 1118–1121, 2009.
¨
¨
[21] Maestro, Schrodinger Release 2016-4, Maestro, Schrodinger,
LLC, New York, NY, USA, 2016.

International Journal of
Advances in
Organic Chemistry
International
International Journal of
Photoenergy
Medicinal Chemistry
Physical Chemistry
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
http://www.hindawi.com
Volume 2014
Volume 201ꢀ
Carbohydrate
Chemistry
Journal of
Quantum Chemistry
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Submit your manuscripts at
https://www.hindawi.com
Journal of
The Scientific
Analytical Methods
in Chemistry
World Journal
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
http://www.hindawi.com
Volume 2014
Volume 2014
International Journal of
Journal of
International Journal of
Bioinorganic Chemistry
Spectroscopy
Inorganic Chemistry
Electrochemistry
and Applications
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
Journal of
Journal of
International Journal of
Chromatography
Journal of
Theoretical Chemistry
Research International
Catalysts
Chemistry
Spectroscopy
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
Volume 2014
Volume 2014
Volume 2014