Design, synthesis and anti-Alzheimer's activity of novel 1,2,3-triazole-chromenone carboxamide derivatives

Article abstract of DOI:10.1016/j.bioorg.2018.10.065

Alzheimer's disease (AD) is a well-known neurodegenerative disorder affecting millions of old people worldwide and the corresponding epidemiological data highlights the significance of the disease. As AD is a multifactorial illness, various single-target directed drugs that have reached clinical trials have failed. Therefore, various factors associated with outset of AD have been considered in targeted drug discovery and development. In this work, a wide range of 1,2,3-triazole-chromenone carboxamides were designed, synthesized, and evaluated for their cholinesterase inhibitory activity. Among them, N-(1-benzylpiperidin-4-yl)-7-((1-(3,4-dimethylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-2H-chromene-3-carboxamide (11b) showed the best acetylcholinesterase inhibitory activity (IC₅₀ = 1.80 μM), however, it was inactive toward butyrylcholinesterase. It should be noted that compound 11b was evaluated for its BACE1 inhibitory activity and calculated IC₅₀ = 21.13 μM confirmed desired inhibitory activity. Also, this compound revealed satisfactory neuroprotective effect against H₂O₂-induced cell death in PC12 neurons at 50 μM as well as metal chelating ability toward Fe²⁺, Cu²⁺, and Zn²⁺ ions.

Full text of DOI:10.1016/j.bioorg.2018.10.065

Accepted Manuscript
Design, synthesis and anti-Alzheimer’s activity of novel 1,2,3-triazole-chrome-
none carboxamide derivatives
Arezoo Rastegari, Hamid Nadri, Mohammad Mahdavi, Alireza Moradi,
Seyedeh Sara Mirfazli, Najmeh Edraki, Farshad Homayouni Moghadam,
Bagher Larijani, Tahmineh Akbarzadeh, Mina Saeedi
PII:
S0045-2068(18)30232-3
DOI:
https://doi.org/10.1016/j.bioorg.2018.10.065
YBIOO 2599
Reference:
Bioorganic Chemistry
To appear in:
Received Date:
Revised Date:
Accepted Date:
7 March 2018
21 October 2018
29 October 2018
Please cite this article as: A. Rastegari, H. Nadri, M. Mahdavi, A. Moradi, S. Sara Mirfazli, N. Edraki, F. Homayouni
Moghadam, B. Larijani, T. Akbarzadeh, M. Saeedi, Design, synthesis and anti-Alzheimer’s activity of novel 1,2,3-
triazole-chromenone carboxamide derivatives, Bioorganic Chemistry (2018), doi: https://doi.org/10.1016/j.bioorg.
2018.10.065
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Design, synthesis and anti-Alzheimer’s activity of novel 1,2,3-triazole-chromenone
carboxamide derivatives
a
b
c
b
Arezoo Rastegari , Hamid Nadri , Mohammad Mahdavi , Alireza Moradi , Seyedeh Sara
d
e
f
c
Mirfazli , Najmeh Edraki , Farshad Homayouni Moghadam , Bagher Larijani , Tahmineh
Akbarzadeh a,g, Mina Saeedi h,g*
a
Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical
Sciences, Tehran, Iran
b
Department of Medicinal Chemistry, Faculty of Pharmacy, Shahid Sadoughi University of
Medical Sciences, Yazd, Iran
c
Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Research
Institute, Tehran University of Medical Sciences, Tehran, Iran
d
Department of Medicinal Chemistry, School of Pharmacy-International Campus, Iran
University of Medical Sciences, Tehran, Iran
e
Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical
Sciences, Shiraz, Iran
f
Department of Cellular Biotechnology at Cell Science Research Center, Royan Institute for
Biotechnology, ACECR, Isfahan, Iran
g
Persian Medicine and Pharmacy Research Center, Tehran University of Medical Sciences,
Tehran, Iran
h
Medicinal Plants Research Center, Faculty of Pharmacy, Tehran University of Medical
Sciences, Tehran, Iran
This paper is dedicated to the memory of our unique teacher in Chemistry and Medicinal
Chemistry, Professor Abbas Shafiee.
*Corresponding author. Medicinal Plants Research Center, Faculty of Pharmacy, Tehran University of Medical
Sciences, Tehran, Iran. E-mail address: m-saeedi@tums.ac.ir (M. Saeedi)
1

Abstract
Alzheimer’s disease (AD) is a well-known neurodegenerative disorder affecting millions of old
people worldwide and the corresponding epidemiological data highlights the significance of the
disease. As AD is a multifactorial illness, various single-target directed drugs that have reached
clinical trials have failed. Therefore, various factors associated with outset of AD have been
considered in targeted drug discovery and development. In this work, a wide range of 1,2,3-
triazole-chromenone carboxamides were designed, synthesized, and evaluated for their
cholinesterase inhibitory activity. Among them, N-(1-benzylpiperidin-4-yl)-7-((1-(3,4-
dimethylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-2H-chromene-3-carboxamide (11b)
showed the best acetylcholinesterase inhibitory activity (IC50 = 1.80 µM), however, it was
inactive toward butyrylcholinesterase. It should be noted that compound 11b was evaluated
for its BACE1 inhibitory activity and calculated IC50 = 21.13 µM confirmed desired inhibitory
activity. Also, this compound revealed satisfactory neuroprotective effect against H2O2-induced
cell death in PC12 neurons at 50 µM as well as metal chelating ability toward Fe2+, Cu2+, and
Zn2+ ions.
Keyword: Alzheimer’s disease, Beta secretase (BACE1), Cholinesterase, Chromenone,
Click reaction, Neuroprotectivity, 1,2,3-Triazole.
1. Introduction
Alzheimer's disease (AD) is the most common type of dementia among older adults
characterized by the several complex pathological fluctuations in the brain. It is manifested
by the failure of memory and thinking skills leading to disability to perform the simplest
tasks. The illness progress is well-known by the advent of aphasia, apraxia, executive
disorders, mood disturbances, and psychiatric symptoms to such an extent a huge economic
2

burden in the form of healthcare and nursing home costs has been imposed on the families,
communities, and governments [1].
The exact origin of AD is ambiguous and combinatorial factors such as genetic,
lifestyle, and environmental are involved in onset and progression of the disease. Formation
of toxic amyloid beta (Aβ) protein in the brain [2], tau protein hyperphosphorylation and
aggregation [3], biometals dysfunction (ions; copper, iron, and zinc) [4,5], alteration of
calcium homeostasis [6], inflammation and oxidative stress due to generation of reactive
oxygen species (ROS) [7], and deficits in the cholinergic transmission [8] have been
considered as the main causes of AD. Although several single factor theories have been
suggested for AD, no one led to definite treatment even more recent pathological hallmarks
of AD related to the accumulation of neurofibrillary tangles and amyloid plaques [9,10] have
failed in clinical trials. Up to now, only temporary symptomatic relief has obtained from
FDA approved anti-cholinesterase (ChE) drugs via improving the cholinergic
neurotransmitter systems [11].
Acetylcholine (ACh) is a chemical compound synthesized from two precursors;
choline and acetyl coenzyme A by enzyme choline O-acetyltransferase. It is well-known to
be involved in physiological processes and regulation of endothelial cells and immune
system cells functions [12]. There are two enzymes, acetylcholinesterase (AChE) and
butyrylcholinesterase (BChE) which are ubiquitous in the body in large amounts targeting
ACh and other choline esters that function as neurotransmitters. AChE has catalytic anionic
site (CAS) and peripheral anionic site (PAS) which are selectively accepting ACh [13].
Hence, ChE inhibitors (ChEIs) have been involved in a wide range of AD drug discovery
research [14]. The efficacy of anti-ChE agents comes back to the fact that the cholinergic
system is extremely affected by the pathological processes in AD to increase accessibility of
ACh [15]. It has been also postulated that there are possible interactions between Aβ and
3

cholinergic neurotransmission especially with the PAS of AChE [16]. Although the ChEIs
usually are known for their symptomatic effects, they have shown new strategies through
neuroprotective effects [17]. Moreover, new version of the cholinergic hypothesis described
by McDonald et al. [18] can be extended to the compensatory role of cholinergic system in
providing protection for hippocampal neurons.
Herein, in continuation of our efforts to develop anti-AD agents [19-24], we designed
and synthesized a novel series of 1,2,3-triazole-chromenone carboxamide derivatives 11
(Scheme 1) which were evaluated for their ChE inhibitory activity. Also, the most potent
AChE inhibitor was investigated for BACE1 inhibitory activity as well as neuroprotective
and metal-chelating properties.
2. Results and discussion
2.1. Design of compounds 11
The design of the target compounds 11 is endorsed by the versatile anti-AD activity
of coumarin and 1,2,3-triazole scaffolds [25-28] (Fig. 1). In this regard, anti-AChE activity
of ensaculine A reported by Hoerr and Noeldner [29] demonstrated high anti-AD activity and
its hydrochloride salt depicted desirable physiochemical properties. Also, the study reported
by Foroumadi et al. [30] has evidently highlighted anti-AChE activity of coumarin-3-
carboxamide derivative B. Study by Sharpless et al. [27] demonstrated that 1,2,3-triazole-
linked tacrine and phenanthridinium derivatives C and D possessed remarkable AChEI
activity by incorporation of 1,2,3-triazole ring. However, introduction of 1,2,3-triazole
moiety into the iminochromene-2H-carboxamide derivative E led to beta secretase (BACE1)
inhibitory activity as reported by Edraki et al. [31]. Hybridization of desired scaffolds
marked in color in Fig. 1 led to the reasonable synthesis of target compounds 11.
2.2. Chemistry
4

Scheme 1 demonstrates schematic synthesis of desired compound 11. For this purpose,
required starting material, ethyl 7-hydroxy-2-oxo-2H-chromene-3-carboxylate 3 was obtained
by the reaction of 2,4-dihydroxybenzaldehyde 1 and diethyl malonate 2 in the presence of
piperidine in EtOH at room temperature. Then, reaction of compound 3 and propargyl bromide
4 in the presence of K2CO3 in DMF at 80 °C gave ethyl 2-oxo-7-(prop-2-yn-1-yloxy)-2H-
chromene-3-carboxylate 5. Hydrolysis of compound 5 using NaOH (5%) in EtOH at room
temperature led to the formation of the corresponding acid, 2-oxo-7-(prop-2-yn-1-yloxy)-2H-
chromene-3-carboxylic acid 6. Reaction of compound 6 and appropriated amine 7 in the
presence of N,N'-dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole hydrate (HOBt)
in dry acetonitrile afforded compound 8. Finally, CuSO4.5H2O-catalyzed click reaction of
compound 8 and in situ prepared benzyl azide derivatives 10 obtained from the reaction of
benzyl chloride/bromide derivative 9 and sodium azide in the presence of trimethylamine in
water/tert-butyl alcohol afforded final products 11.
2.3. In vitro anti-AChE and anti-BChE activity
In vitro anti-AChE and anti-BChE activity of synthesized compounds 11 was
conducted based on modified Ellman’s method [32] (Table 1). The synthesized compounds
11 can be generally divided into two categories based on the different amine moiety
connected to amide functional group, benzylpiperidinyl (11a-j) and 3-morpholinopropyl
(11k-s).
As can be seen in Table 1, the best AChEI activity was obtained by compound 11b
(IC50 = 1.80 µM) in comparison to donepezil as the reference drug (IC50 = 0.027 µM). The
compound possessed benzylpiperidinyl moiety connected to amide functional group and 3,4-
dimethylbenzyl connected to 1,2,3-traizole moiety. Reduction of the number of methyl group
as well as changing its position reduced the inhibitory activity of compounds 11c and 11d
with IC50s = 20.00 and 3.70 µM, respectively. Also, changing 3,4-dimethylbenzyl to 3,4-
5

dichlorobenzyl group led to a brief reduction of AChEI activity of compound 11i with IC50 =
2.04 µM, however, reduction of the number of chlorine group and changing their position
led to the reduction of anti-AChE activity of compounds 11g and 11h with IC50s = 3.30 and
18.56 µM, respectively.
Compounds 11f, 11g, and 11d showed similar activity with IC50s = 3.29, 3.30, and
3.70 µM demonstrating that compounds containing 2-substituted benzyl moieties induced
similar anti-AChE activity independent of electronic property of substituents in the series of
compounds 11a-j. Compound 11a having benzyl group with no substituents afforded
moderate activity toward AChE (IC50 = 4.50 µM). Its analogue 11j containing fluorine
showed lower activity (IC50 = 10.10 µM) despite the similarity between atomic size of
hydrogen and fluorine. Of course, the lowest active compound in this series was compound
11e having 4-methoxybenzyl group. Apparently, the presence of strong electron donating
substituent deteriorated inhibitory activity toward AChE (IC50 = 36.50 µM).
In the series of compounds 11k-s, compound 11m having 3-morpholinopropyl and 2-
bromobenzyl moieties showed good inhibitory activity toward AChE (IC50 = 2.10 µM).
However, the activity was not significantly lower than two compounds 11b and 11i.
Replacement of bromine by other halogens led to lower activity in compound 11n-s. It was
interesting that changing the position of chlorine in compounds 11n and 11o afforded
different activity. Compound 11n having 2,3-dichlorobenzyl group showed IC50 = 5.03 µM
whereas compound 11o having 3,4-dichlorobenzyl group showed IC50 = 102.68 µM.
Compound 11p and 11q having 4- and 3-chlorobenzyl group showed IC50s = 29.40 and 16.20
µM, respectively. In the case of fluorine substituted compounds (11r and 11s), changing the
position of fluorine did not show a significant difference; however, 4-fluorobenzyl induced
better activity. It should be noted that compounds 11k and 11l possessing 4- and 2-
methylbenzyl moieties, respectively demonstrated similar manner comparing with their
6

counterparts 11c and 11d as 2-methyl substituted derivative depicted better activity than 4-
methyl substituted derivative.
It seems that benzylpiperidinyl moiety induced better anti-AChE activity than 3-
morpholinopropyl which can be associated to similar moiety (benzylpiperidinyl) ubiquitous
in donepezil. Also, the presence of benzylpiperidinyl moiety and 3,4-disubstituted benzyl
group connected to 1,2,3-triazole ring is significant for induction of AChEI activity in this
series of 1,2,3-triazole-chromenone carboxamides 11.
In the case of anti-BChE activity, compounds possessing benzylpiperidinyl moiety
except 11e showed no activity. However, compound 11e showed moderate BChEI activity
with IC50 = 6.18 µM comparing with donepezil (IC50 = 4.32 µM). As can be seen in Table 1,
the presence of 3-morpholinopropyl induced much more better inhibitory activity toward
BChE. Among anti-BChE compounds 11k-s, compounds 11n and 11q having chlorine on the
aryl group connected to 1,2,3-triazole moiety were found to be the most potent agents with
IC50 = 1.71 and 1.85 µM, respectively. Changing the position of chlorine to 3,4- and 4- in
compounds 11o and 11p led to the reduction of activity (IC50s = 8.70 and 32.08 µM,
respectively). It is clear that the presence of chlorine at 3-position of benzyl group played a
significant role in BChEI activity. Also, introduction of fluorine instead of chlorine led to
different results. Generally, fluorinated derivatives 11r and 11s depicted lower activity (IC50s
= 5.40 and 74.30 µM, respectively) than chlorinated counterparts 11n-q and inversely 4-F
derivative 11r was more active than 3-F derivative 11s by 15 times. It should be noted that
compounds 11m possessing bromine showed moderate activity (IC50 = 6.92 µM). Finally,
our results related to compounds possessing methyl group on the aryl group connected to
1,2,3-triazole ring showed that compound 11k having 4-methylbenzyl (IC50 = 7.13 µM) was
more active than compound 11l possessing 3-methylbenzyl (IC50 = 62.00 µM). It seems that
anti-BChE activity is relatively affected by the type of amine connected to the amide moiety
7

as well as position and electronic properties substituents on the aryl group connected to
1,2,3-triazole ring.
To conclude, comparing our results with those previously reported on ChEI activity
of different 1,2,3-triazole-chromenone carboxamides [19] (F, Fig. 2) revealed that changing
the manner of hybridization along with incorporation of desired positive charge centers led to
much better results in this work. Also, compounds 11 had supremacy over 1,2,3-triazole-
chromenones G [33] which depicted no ChEI activity confirming the fact that carboxamide
moiety plays important in inducing anti-ChE activity.
2.4. Kinetic study of AChE inhibition
The kinetic study of AChE inhibition was studied for the most active compound 11b
with IC50 value of 1.80 µM. For this purpose, the rate of AChE inhibition by different
concentrations (0, 1, 2 and 4 µM) of the potent inhibitor 11b was measured in the presence of
acetylthiocholine iodide (ATCh). The cholinesterase inhibition was based on the modified
Ellman’s method [32]. For each inhibitor concentration, the initial velocity was measured at
different substrate concentrations (S) and the reciprocal of the initial velocity (1/V) was plotted
respect to the reciprocal of substrate concentration (1/[S]). Accordingly, the Lineweaver-Burk
plot for the inhibition of AChE and the secondary plot for calculation of steady-state inhibition
constant (Ki) for compound 11b were illustrated in Fig. 3. The Lineweaver-Burk plot showed a
mixed-type inhibition pattern for compound 11b against AChE. The Ki value was 1.37 µM as
calculated from the secondary plot in Fig. 3.
2.5. β-secretase (BACE1) inhibitory activity of compound 11b
Cleavage of amyloid precursor protein (APP) by β-secretase (BACE1) results in the
formation of soluble N-terminal fragment and the 99-residue C-terminal fragment of APP
(C99). Further cleavage of C99 by another enzyme known as γ-secretase produces Aβ peptides.
Since BACE1 clearly plays a direct role in the production of the Aβ peptides, several studies
8

have focused on design and synthesis of selective inhibitors [31]. In this study, the most active
anti-AChE compound 11b was evaluated for its BACE1 inhibitory activity using FRET assay
kit comparing with OM99-2 (IC50 = 0.014 µM) [19,31]. Compound 11b showed relatively good
inhibitory activity with IC50 = 21.13 µM.
2.6. Neuroprotective effect of compound 11b against H2O2-induced cell death in PC12 neurons
Protective effect of compound 11b was evaluated in comparison to intact (normal, no
intervention), quercetin+ H2O2-treated (positive control) and H2O2-treated (negative control)
cells (Fig. 4). Compound 11b showed moderate to good neuroprotectivity at 50 and 100 µM (P
<0. 01 & P <0.0001 vs. H2O2-treated, respectively). It should be noted that compound 11b did
not show stronger activity than quercetin (P<0.0001, all 11b treated groups vs. quercetin+H2O2-
treated). There were significant differences between intact and other H2O2-treated groups
indicating that apoptosis was successfully occurred in all of the H2O2-treated groups (P<0.0001,
intact vs. other groups).
2.7. Metal chelating
Role of oxidative stress in the pathogenesis of AD has been widely supported in the
literature since levels of lipid peroxidation, DNA and protein oxidation products increase in the
brain of patients with AD. Unregulated reaction of molecular oxygen with the redox active
metals such as Fe, Cu, and Zn leads to the generation of ROS [34]. However, the role of metal-
ion homeostasis especially in the central nervous system needs to be considered in design of
anti-AD agents. Herein, the most active AChE inhibitor 11b was studied for its chelating ability
toward Cu2+, Fe2+ and Zn2+ in methanol using UV-vis spectrophotometer. As can be seen in Fig.
5, UV absorption of compound 11b depicted a blue shift with addition of Cu2+ or Zn2+
confirming the interaction of 11b and those metal ions (Fig. 5, A). However, little change was
observed by adding Fe2+. The stoichiometry of complex 11b-Zn2+ was determined using the
molar ratio method [35] through titrating solutions of compound 11b by increased amounts of
9

ZnCl2 (Fig. 5, B). Accordingly, intersection of two straight lines was obtained at the mole
fraction of 1.00 representing a 1:1 stoichiometry for the 11b-Zn2+ complex.
2.8. Ligand-protein docking study
The most promising compound 11b was selected for docking study with
acetylcholinesterase (1EVE) by using the AutoDock vina software. As depicted in Fig. 6 and 7,
compound 11b was positioned in the enzyme active site in such a way to interact with the
amino acids at the rim of the cavity, and to act as a barrier preventing the entry of the substrates
into the active site. Furthermore, the rest of the molecule pass through the gorge and interact
with the CAS. The coumarin fragment, which has an approximately planar structure, made π-π
stacking with the aromatic amino acids of the mid-gorge including tyrosine 69 and tryptophan
278. Moreover, the 1,2,3-triazole linker bound to tryptophan 278 by a π-π interaction. In this
situation, the NH of amide bond made a hydrogen bond with tyrosine 120. The pendent
substituted aryl group connected to 1,2,3-triazole was placed in the hydrophobic cavity made by
isoleucine 286 and phenylalanine 289. On the opposite side of the ligand, benzyl moiety made a
π- π interaction with tryptophan 83.
3. Conclusion
In conclusion, a proficient synthetic route was described for the design and synthesis
of novel 1,2,3-triazole-chromenone carboxamide derivatives as potent anti-AD agents. Most
of synthesized compounds showed good AChEI activity and among them, compound 11b
was found to be the most potent agent with IC50 = 1.80 µM. Kinetic study of compound 11b
revealed mixed type inhibition toward the CAS and the PAS of AChE. Furthermore,
compound 11n showed good anti-BChE activity (IC50 = 1.71 µM). It should be noted that
compound 11b showed inhibitory activity toward BACE1 with calculate IC50 = 21.13 µM
and satisfactory metal-chelating property towards Cu2+ and Zn2+ ions. However, our results
10

demonstrated that it possessed desirable neuroprotectivity which can be considered for further
investigations for anti-AD drug developments. Comparing our results with those reported in the
literature associated with hybridization of 1,2,3-triazole and chromenone moieties [19,33]
confirmed the necessity of the presence of carboxamide moiety as well as the arrangement of
1,2,3-triazole and coumarin scaffolds. However, ChEI activity was directly affected by the
positive charge center and electronic property of substituents on the benzyl group connected to
1,2,3-triazole ring.
4. Experimental
1
Melting points were determined on a Kofler hot stage apparatus and are uncorrected. H
and 13C NMR spectra were recorded on a Bruker FT-500, using TMS as an internal standard. IR
spectra were obtained on a Nicolet Magna FTIR 550 spectrophotometer (KBr disks). Elemental
analysis was performed on an Elementar Analysensystem GmbH VarioEL CHNS mode. The
UV-Vis absorption spectra were recorded on a double beam GBC Cintra 101.
4.1. General procedure for the synthesis of 1,2,3-triazole-chromenone carboxamides 11
A mixture of 2,4-dihydroxybenzaldehyde 1 (1mmol), diethyl malonate 2 (1mmol), and
piperidine (1 mmol) in EtOH (10 mL) was stirred at room temperature for 4-5 h. After
completion of the reaction (checked by TLC), the mixture was poured into water to precipitate
ethyl 7-hydroxy-2-oxo-2H-chromene-3-carboxylate 3. Next, compound 3 (1 mmol) reacted with
propargyl bromide 4 (1 mmol) in the presence of K2CO3 (1 mmol) in DMF (5 mL) at 80 °C for
5 h. Then, the mixture was poured into cold water and the precipitates were filtered off and
washed with water to obtain ethyl 2-oxo-7-(prop-2-yn-1-yloxy)-2H-chromene-3-carboxylate 5.
Compound 5 (1 mmol) was stirred in the presence of NaOH 5% (5 mL) in EtOH (5 mL) at
room temperature for 4-5 h. After completion of the reaction (checked by TLC), the mixture
11

was neutralized with HCl 5%, the precipitates were filtered off, washed with water to afford the
corresponding acid 6. A solution of compound 6 (1 mmol), DCC (1.1 mmol), and HOBt (1
mmol) in dry acetonitrile (5 mL) was stirred at room temperature for 30 min. Then,
appropriated amine 7 (1 mmol) was added to the mixture and the reaction was continued at
room temperature for 20-24 h. After completion of the reaction, the solvent was reduced under
vacuum and the residue was dissolved in dichloromethane and washed with citric acid and
sodium hydrogen carbonate (10%). The organic phase was dried over anhydrous Na2SO4 and
the solvent was evaporated. The obtained compound 8 was completely pure and used for further
reaction. Finally, a solution of benzyl chloride/bromide derivative 9 (1.1 mmol), sodium azide
(0.06 g, 0.9 mmol), and trimethylamine (0.13 g, 1.3 mmol) in water (4 mL) and tert-butyl
alcohol (4 mL) was stirred at room temperature for 30 min. Then, compound 8 (0.5 mmol) and
CuSO4.5H2O (7 mol%) were added to the reaction mixture and it was continued for 24 h. Upon
completion of the reaction, monitored by TLC, the mixture was diluted with water, extracted
with chloroform, and dried over anhydrous Na2SO4. After evaporation of solvent, the residue
was recrystallized from ethyl acetate and petroleum ether to give pure product 11.
4.1.1. 7-((1-Benzyl-1H-1,2,3-triazol-4-yl)methoxy)-N-(1-benzylpiperidin-4-yl)-2-oxo-2H-
chromene-3-carboxamide (11a)
o
Yield: 75%, white solids, mp 206-208 C. IR (KBr): 3337, 2932, 2806, 1710, 1650, 1610, 1560
1
cm-1. H NMR (500 MHz: DMSO-d6): 1.52-1.54 (m, 2H, CH2), 1.84-1.86 (m, 2H, CH2), 2.14-
2.16 (m, 2H, CH2), 2.70-2.71 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.80-3.82 (m, 1H, CH), 5.30 (s,
2H, CH2), 5.62 (s, 2H, CH2), 7.09 (d, J = 9.0 Hz, 1H, H6), 7.27-7.37 (m, 11H, Ph, H8), 7.90 (d,
13
J = 9.0 Hz, 1H, H5), 8.35 (s, 1H, triazole), 8.59 (d, J = 7.5 Hz, 1H, NH), 8.82 (s, 1H, H4). C
NMR (125 MHz: DMSO-d6): 31.4, 46.5, 51.5, 52.9, 61.9, 62.1, 95.2, 101.1, 112.4, 114.1, 115.0,
125.1, 126.9, 128.0, 128.2, 128.8, 131.6, 133.8, 135.9, 138.5, 142.0, 147.7, 156.0, 160.5, 161.5,
12

163.0. Anal. calcd. for C32H31 N5O4: C, 69.93; H, 5.69; N, 12.74. Found: C, 70.17; H, 5.82; N,
12.61.
4.1.2. N-(1-Benzylpiperidin-4-yl)-7-((1-(3,4-dimethylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-
oxo-2H-chromene-3-carboxamide (11b)
o
Yield: 70%, white solids, mp 185-187 C. IR (KBr): 3330, 2940, 2807, 1707, 1652, 1610, 1530
1
cm-1. H NMR (500 MHz: DMSO-d6): 1.50-1.56 (m, 2H, CH2), 1.85-1.87 (m, 2H, CH2), 2.14-
2.16 (m, 2H, CH2), 2.23 (s, 6H, 2 × CH3), 2.69-2.71 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.80-3.82
(m, 1H, CH), 5.30 (s, 2H, CH2), 5.52 (s, 2H, CH2), 6.93-6.95 (m, 3H, H8, H2', H6'), 7.09 (dd, J
= 9.0, 2.0 Hz, 1H, H6), 7.24-7.34 (m, 6H, Ph, H4'), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.32 (s, 1H,
triazole), 8.59 (d, J = 7.5 Hz, 1H, NH), 8.81 (s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 20.8,
31.4, 46.2, 51.5, 52.9, 61.9, 62.1, 95.4, 101.1, 112.4, 114.1, 115.0, 125.1, 125.7, 126.9, 128.1,
128.7, 129.6, 131.6, 135.7, 137.9, 141.9, 147.7, 156.0, 160.6, 161.0, 163.0. Anal. calcd. for
C34H35N5O4: C, 70.69; H, 6.11; N, 12.12. Found: C, 70.53; H, 6.27; N, 12.28.
4.1.3. N-(1-Benzylpiperidin-4-yl)-7-((1-(4-methylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-
2H-chromene-3-carboxamide (11c)
Yield: 72%, white solids, mp 170-172 oC. IR (KBr): 3328, 3050, 2939, 2809, 1706, 1654, 1610,
1
1542 cm-1. H NMR (500 MHz: DMSO-d6): 1.50-1.56 (m, 2H, CH2), 1.85-1.87 (m, 2H, CH2),
2.15-2.17 (m, 2H, CH2), 2.27 (s, 3H, CH3), 2.70-2.72 (m, 2H, CH2), 3.48 (s, 2H, CH2), 3.80-
3.82 (m, 1H, CH), 5.29 (s, 2H, CH2), 5.56 (s, 2H, CH2), 7.09 (dd, J = 9.0, 2.5 Hz, 1H, H6),
7.17-7.34 (m, 10H, Ph, H3', H4', H5', H6', H8), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.31 (s, 1H,
triazole), 8.59 (d, J = 7.5 Hz, 1H, NH), 8.82 (s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 20.7,
31.4, 47.5, 51.5, 52.7, 61.9, 62.1, 95.1, 101.1, 112.4, 114.1, 115.3, 125.0, 126.8, 128.0, 128.1,
128.7, 129.3, 131.5, 133.0, 137.5, 141.9, 147.7, 156.0, 160.7, 161.3, 163.2. Anal. calcd. for
C33H33N5O4: C, 70.32; H, 5.90; N, 12.43. Found: C, 70.45; H, 6.11; N, 12.56.
13

4.1.4. N-(1-Benzylpiperidin-4-yl)-7-((1-(2-methylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-
2H-chromene-3-carboxamide (11d)
Yield: 70%, white solids, mp 199-201 oC. IR (KBr): 3339, 3050, 2928, 2850, 1710, 1650, 1610,
1
1560 cm-1. H NMR (500 MHz: DMSO-d6): 1.52-1.54 (m, 2H, CH2), 1.85-1.86 (m, 2H, CH2),
2.16-2.17 (m, 2H, CH2), 2.31 (s, 3H, CH3), 2.71-2.72 (m, 2H, CH2), 3.48 (s, 2H, CH2), 3.78-
3.80 (m, 1H, CH), 5.30 (s, 2H, CH2), 5.63 (s, 2H, CH2), 7.08-7.32 (m, 11H, Ph, H3', H4', H5',
H6', H6, H8), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.25 (s, 1H, triazole), 8.59 (d, J = 7.5 Hz, 1H, NH),
8.81 (s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 18.6, 31.3, 48.1, 51.0, 51.4, 61.9, 62.0, 95.1,
101.1, 112.3, 114.1, 115.0, 125.2, 126.2, 126.9, 128.1, 128.4, 128.8, 130.4, 131.5, 134.0, 136.3,
138.5, 141.9, 147.7, 156.0, 160.5, 161.0, 163.0. Anal. calcd. for C33H33N5O4: C, 70.32; H, 5.90;
N, 12.43. Found: C, 70.51; H, 5.76; N, 12.28.
4.1.5. N-(1-Benzylpiperidin-4-yl)-7-((1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-
oxo-2H-chromene-3-carboxamide (11e)
o
Yield: 71%, white solids, mp 183-185 C. IR (KBr): 3335, 2942, 2825, 1710, 1650, 1610, 1530
1
cm-1. H NMR (500 MHz: DMSO-d6): 1.52-1.54 (m, 2H, CH2), 1.84-1.85 (m, 2H, CH2), 2.15-
2.17 (m, 2H, CH2), 2.69-2.71 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.73 (s, 3H, OCH3), 3.80-3.82
(m, 1H, CH), 5.29 (s, 2H, CH2), 5.53 (s, 2H, CH2), 6.92-7.31 (m, 11H, Ph, H2', H3', H5', H6',
H6, H8), 7.89 (d, J = 9.0 Hz, 1H, H5), 8.28 (s, 1H, triazole), 8.57 (d, J = 7.5 Hz, 1H, NH), 8.80
(s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 31.3, 43.8, 47.5, 51.3, 52.4, 55.1, 62.0, 95.5,
101.1, 114.1, 115.2, 122.8, 123.9, 124.6, 126.8, 128.0, 128.6, 129.5, 131.4, 137.1, 141.9, 147.5,
155.8, 160.2, 160.8, 161.1, 163.4. Anal. calcd. for C33H33N5O5: C, 68.38; H, 5.74; N, 12.08.
Found: C, 68.22; H, 5.59; N, 12.21.
4.1.6. N-(1-Benzylpiperidin-4-yl)-7-((1-(2-bromobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-
2H-chromene-3-carboxamide (11f)
14

Yield: 75%, white solids, mp 185-187 oC. IR (KBr): 3342, 2939, 2820, 1708, 1650, 1610, 1559,
1
1526 cm-1. H NMR (500 MHz: DMSO-d6): 1.50-1.56 (m, 2H, CH2), 1.85-1.87 (m, 2H, CH2),
2.13-2.15 (m, 2H, CH2), 2.69-2.71 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.79-3.81 (m, 1H, CH),
5.32 (s, 2H, CH2), 5.71 (s, 2H, CH2), 7.10 (dd, J = 8.5, 2.0 Hz, 1H, H6), 7.21 (dd, J = 8.0, 1.5
Hz, 1H, H6'), 7.23-7.32 (m, 7H, Ph, H8, H4'), 7.41 (t, J = 8.0 Hz, 1H, H5'), 7.69 (d, J = 8.0 Hz,
1H, H3'), 7.90 (d, J = 8.5 Hz, 1H, H5), 8.32 (s, 1H, triazole), 8.59 (d, J = 7.5 Hz, 1H, NH), 8.82
13
(s, 1H, H4). C NMR (125 MHz: DMSO-d6): 31.4, 46.3, 51.5, 53.0, 61.8, 62.1, 95.1, 101.1,
112.4, 114.2, 115.0, 125.6, 126.8, 128.1, 128.3, 128.7, 130.5, 130.6, 131.6, 132.9, 134.7, 138.5,
141.8, 147.7, 156.1, 160.8, 161.0, 163.0. Anal. calcd. for C32H30BrN5O4: C, 61.15; H, 4.81; N,
11.14. Found: C, 61.28; H, 4.67; N, 11.31.
4.1.7. N-(1-Benzylpiperidin-4-yl)-7-((1-(2-chlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-
2H-chromene-3-carboxamide (11g)
Yield: 70%, white solids, mp 201-203 oC. IR (KBr): 3340, 3050, 2941, 2806, 1708, 1649, 1610,
1
1561, 1524 cm-1. H NMR (500 MHz: DMSO-d6): 1.50-1.52 (m, 2H, CH2), 1.78-1.80 (m, 2H,
CH2), 2.14-2.15 (m, 2H, CH2), 2.70-2.72 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.80-3.82 (m, 1H,
CH), 5.31 (s, 2H, CH2), 5.73 (s, 2H, CH2), 7.09 (d, J = 9.0 Hz, 1H, H6), 7.25-7.40 (m, 9H, Ph,
H4', H5', H6', H8), 7.51 (d, J = 7.5 Hz, 1H, H3'), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.33 (s, 1H,
triazole), 8.59 (d, J = 7.5 Hz, 1H, NH), 8.82 (s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 31.4,
47.2, 50.7, 51.5, 61.8, 62.1, 95.1, 101.1, 112.4, 114.1, 115.0, 125.5, 126.9, 127.7, 128.1, 128.7,
129.6, 130.3, 130.6, 131.5, 132.7, 133.1, 141.8, 147.7, 156.0, 160.6, 161.0, 163.1. Anal. calcd.
for C32H30ClN5O4: C, 65.81; H, 5.18; N, 11.99. Found: C, 67.64; H, 5.31; N, 12.18.
4.1.8. N-(1-Benzylpiperidin-4-yl)-7-((1-(2,3-dichlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-
oxo-2H-chromene-3-carboxamide (11h)
o
Yield: 70%, white solids, mp 217-2019 C. IR (KBr): 3334, 2932, 2850, 1708, 1650, 1610,
1
1560, 1529 cm-1. H NMR (500 MHz: DMSO-d6): 1.50-1.52 (m, 2H, CH2), 1.85-1.87 (m, 2H,
15

CH2), 2.15-2.17 (m, 2H, CH2), 2.70-2.72 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.80-3.82 (m, 1H,
CH), 5.32 (s, 2H, CH2), 5.79 (s, 2H, CH2), 7.10 (d, J = 9.0 Hz, 1H, H6), 7.20 (d, J = 8.0 Hz, 1H,
H6'), 7.25-7.39 (m, 6H, Ph, H8), 7.40 (t, J = 8.0 Hz, 1H, H5'), 7.67 (d, J = 8.0 Hz, 1H, H4'),
7.90 (d, J = 9.0 Hz, 1H, H5), 8.36 (s, 1H, triazole), 8.59 (d, J = 7.5 Hz, 1H, NH), 8.82 (s, 1H,
H4). 13C NMR (125 MHz: DMSO-d6): 31.3, 47.1, 51.2, 51.4, 61.8, 62.1, 95.1, 101.1, 112.4,
114.1, 115.1, 125.1, 126.9, 128.2, 128.7, 128.8, 129.1, 130.6, 131.6, 132.2, 135.8, 137.1, 141.9,
147.7, 156.0, 160.6, 161.0, 163.0. Anal. calcd. for C32H29Cl2N5O4: C, 62.14; H, 4.73; N, 11.32.
Found: C, 62.31; H, 4.58; N, 11.50.
4.1.9. N-(1-Benzylpiperidin-4-yl)-7-((1-(3,4-dichlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-
oxo-2H-chromene-3-carboxamide (11i)
Yield: 72%, white solids, mp 184-186 oC. IR (KBr): 3318, 3063, 2945, 2806, 1706, 1651, 1611,
1
1548 cm-1. H NMR (500 MHz: DMSO-d6): 1.50-1.56 (m, 2H, CH2), 1.85-1.87 (m, 2H, CH2),
2.13-2.17 (m, 2H, CH2), 2.69-2.71 (m, 2H, CH2), 3.47 (s, 2H, CH2), 3.80-3.82 (m, 1H, CH),
5.32 (s, 2H, CH2), 5.65 (s, 2H, CH2), 7.10 (dd, J = 9.0, 2.0 Hz, 1H, H6), 7.23-7.32 (m, 6H, Ph,
H8), 7.64-7.63 (m, 3H, H2', H5', H6'), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.40 (s, 1H, triazole), 8.59
13
(d, J = 7.5 Hz, 1H, NH), 8.82 (s, 1H, H4). C NMR (125 MHz: DMSO-d6): 31.4, 47.0, 51.4,
51.5, 61.8, 62.1, 95.6, 101.1, 108.4, 112.4, 114.1, 115.0, 125.3, 126.8, 128.1, 128.5, 128.7,
130.2, 131.0, 131.6, 136.8, 138.5, 142.1, 147.7, 156.0, 160.6, 161.0, 163.0. Anal. calcd. for
C32H29Cl2N5O4: C, 62.14; H, 4.73; N, 11.32. Found: C, 62.26; H, 4.84; N, 11.19.
4.1.10. N-(1-Benzylpiperidin-4-yl)-7-((1-(4-fluorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-oxo-
2H-chromene-3-carboxamide (11j)
Yield: 75%, white solids, mp 213-215 oC. IR (KBr): 3333, 2931, 2804, 1712, 1650, 1610, 1560,
1
1529 cm-1. H NMR (500 MHz: DMSO-d6): 1.52-1.54 (m, 2H, CH2), 1.84-1.87 (m, 2H, CH2),
2.14-2.15 (m, 2H, CH2), 2.69-2.70 (m, 2H, CH2), 3.48 (s, 2H, CH2), 3.80-3.82 (m, 1H, CH),
5.30 (s, 2H, CH2), 5.61 (s, 2H, CH2), 7.09 (dd, J = 9.0, 2.5 Hz, 1H, H6), 7.19-7.42 (m, 10H, Ph,
16

H2', H3', H5', H6', H8), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.35 (s, 1H, triazole), 8.59 (d, J = 7.5 Hz,
13
1H, NH), 8.82 (s, 1H, H4). C NMR (125 MHz: DMSO-d6): 31.4, 47.1, 51.4, 52.1, 61.9, 62.1,
95.2, 101.1, 114.1, 115.6 (d, JC-F = 22.5 Hz), 125.0, 126.9, 128.1, 128.7, 130.4 (d, JC-F = 8.7
Hz), 131.6, 131.9, 135.9, 138.5, 142.0, 147.7, 156.2, 160.8, 161.3, 163.0, 163.1 (d, JC-F = 245.0
Hz). Anal. calcd. for C32H30FN5O4: C, 67.71; H, 5.33; N, 12.34. Found: C, 67.59; H, 5.18; N,
12.56.
4.1.11. 7-((1-(4-Methylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11k)
o
Yield: 80%, white solids, mp 172-173 C. IR (KBr) cm-1: 3328, 2942, 2810, 2767, 1707, 1610,
1
1545. H NMR (500 MHz, DMSO-d6 ): 1.25-1.27 (m, 2H, CH2), 1.81 (s, 3H, CH3), 2.47-2.49
(m, 6H, 3×CH2), 3.47-3.49 (m, 2H, CH2), 3.74-3.76 (m, 4H, 2×CH2), 5.30 (s, 2H, CH2), 5.55 (s,
2H, CH2), 6.84 (d, J = 9.0 Hz, 1H, H6), 7.04-7.05 (m, 4H, H2ʹ, H3ʹ, H5ʹ, H6ʹ), 7.82 (d, J = 9.0
13
Hz, 1H, H5), 8.21 (s, 1H, triazole), 8.59 (m, 1H, NH), 8.69 (s, 1H, H4). C NMR (125 MHz,
DMSO-d6 ): 20.5, 26.0, 38.3, 49.7, 53.8, 56.6, 61.8, 62.5, 95.3, 101.1, 111.5, 113.6, 124.8, 127.9
129.2, 131.5, 132.8, 137.4, 141.9, 148.9, 156.1, 156.7, 162.7, 163.3. Anal. calcd. for
C28H31N5O5: C, 64.98; H, 6.04; N, 13.53. Found: C, 65.28; H, 5.87; N, 13.74.
4.1.12. 7-((1-(2-Methylbenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11l)
o
Yield: 72%, white solids, mp 174-175 C. IR (KBr): 3435, 2935, 2810, 2767, 1709, 1614, 1565
cm-1. 1H NMR (500 MHz, DMSO-d6): 1.29-1.32 (m, 2H, CH2), 2.30 (s, 3H, CH3), 2.47-2.49 (m,
4H, 2×CH2), 3.21-3.30 (m, 4H, 2×CH2), 4.26-4.30 (m, 4H, 2×CH2), 5.30 (s, 2H, CH2), 5.55 (s,
2H, CH2), 7.05 (dd, J = 9.0, 1.0 Hz, 1H, H6), 7.09-7.24 (m, 5H, H8, H3ʹ, H4ʹ, H5ʹ, H6ʹ), 7.82
(d, J = 9.0 Hz, 1H, H5), 8.21(s, 1H, triazole), 8.55(bs, 1H, NH), 8.69(s, 1H, H4). 13C NMR (125
MHz, DMSO-d6): 18.5, 25.1, 39.0, 50.1, 51.0, 56.0, 60.8, 61.8, 95.1, 101.1, 111.6, 113.6, 125.0,
17

126.1, 128.2, 128.6, 130.3, 131.5, 133.8, 136.2, 141.8, 148.9, 156.1, 156.7, 162.7, 163.3. Anal.
calcd. for C28H31N5O5: C, 64.98; H, 6.04; N, 13.53. Found: C, 64.70; H, 6.28; N, 13.29.
4.1.13. 7-((1-(2-Bromobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11m)
o
Yield: 65%, white solids, mp 180-181 C. IR (KBr): 3340, 2945, 2825, 1705, 1655, 1610, 1561
1
cm-1. H NMR (500 MHz: DMSO-d6): 1.78-1.80 (m, 2H, CH2), 2.33-2.34 (m, 6H, 3×CH2),
3.40-3.42 (m, 2H, CH2), 3.57-3.58 (m, 4H, CH2), 5.30 (s, 2H, CH2), 5.79 (s, 2H, CH2), 7.03-
7.69 (m, 5H, H6, H8, H4ʹ, H5ʹ, H6ʹ), 7.90 (d, J = 8.5 Hz, 1H, H3ʹ), 8.30-8.32 (m, 2H, H5,
triazole), 8.76 (bs, 1H, NH), 8.23 (s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 25.5, 38.0,
53.0, 53.4, 56.0, 61.1, 66.1, 95.4, 103.1, 114.4, 115.1, 125.6, 128.3, 129.4, 130.5, 131.3, 132.9,
134.5, 136.0, 142.0, 147.3, 155.8, 160.2, 161.4, 163.0. Anal. calcd. for C27H28BrN5O5: C, 55.68;
H, 4.85; N, 12.02. Found: C, 55.41; H, 4.68; N, 11.84.
4.1.14. 7-((1-(2,3-Dichlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-
oxo-2H-chromene-3-carboxamide (11n)
o
Yield: 70%, white solids, mp 173-175 C. IR (KBr): 3340, 2940, 2825, 1707, 1650, 1610, 1560
cm-1. 1H NMR (500 MHz: DMSO-d6): 1.69 (quintet, J = 7.0 Hz, 2H, CH2), 2.34-2.36 (m, 6H, 3
× CH2), 3.36 (t, J = 7.0 Hz, 2H, CH2), 3.57-3.59 (m, 4H, 2×CH2), 5.33 (s, 2H, CH2), 5.79 (s,
2H, CH2), 7.09 (dd, J = 8.5, 2.0 Hz, 1H, H6), 7.20 (d, J = 8.0 Hz, 1H, H6'), 7.27 (d, J = 2.0 Hz,
1H, H8), 7.41 (t, J = 8.0 Hz, 1H, H5'), 7.67 (d, J = 8.0 Hz, 1H, H4'), 7.90 (d, J = 8.5 Hz, 1H,
H5), 8.37 (s, 1H, triazole), 8.77 (t, J = 6.0 Hz, 1H, NH), 8.83 (s, 1H, H4). 13C NMR (125 MHz:
DMSO-d6): 25.6, 38.1, 51.2, 53.3, 56.1, 61.8, 66.0, 95.4, 110.1, 112.4, 114.0, 115.1, 125.7,
128.6, 129.1, 130.6, 131.5, 132.2, 135.8, 141.9, 147.6, 155.9, 160.7, 161.2, 162.9. Anal. calcd.
for C27H27Cl2N5O5: C, 56.65; H, 4.75; N, 12.23. Found: C, 56.80; H, 4.58; N, 12.38.
4.1.15. 7-((1-(3,4-Dichlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-
oxo-2H-chromene-3-carboxamide (11o)
18

o
Yield: 70%, white solids, mp 144-146 C. IR (KBr): 3340, 2919, 2820, 1710, 1650, 1610, 1560
1
cm-1. H NMR (500 MHz: DMSO-d6): 1.68 (quintet, J = 6.5 Hz, 2H, CH2), 2.34-2.36 (m, 6H,
3×CH2), 3.36 (t, J = 6.5 Hz, 2H, CH2), 3.57-3.59 (m, 4H, 2×CH2), 5.32 (s, 2H, CH2), 5.66 (s,
2H, CH2), 7.10 (d, J = 9.0 Hz, 1H, H6), 7.27 (s, 1H, H8), 7.32 (d, J = 8.5 Hz, 1H, H6'), 7.63-
7.66 (m, 2H, H2', H5'), 7.90 (d, J = 9.0 Hz, 1H, H5), 8.41 (s, 1H, triazole), 8.77 (t, J = 6.0 Hz,
13
1H, NH), 8.83 (s, 1H, H4). C NMR (125 MHz: DMSO-d6): 25.6, 38.0, 51.5, 53.3, 56.1, 61.8,
66.0, 95.4, 101.1, 112.4, 114.0, 115.3, 125.3, 128.5, 130.2, 131.0, 131.3, 131.5, 136.9, 142.2,
147.6, 156.0, 160.5, 161.1, 163.0. Anal. calcd. for C27H27Cl2N5O5: C, 56.65; H, 4.75; N, 12.23.
Found: C, 56.52; H, 4.51; N, 12.42.
4.1.16. 7-((1-(4-Chlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11p)
Yield: 73%, white solids, mp 182-183 oC. IR (KBr): 3347, 3063, 2926, 2856, 1715, 1613, 1532.
1H NMR (500 MHz, CDCl3): 1.80-1.81 (m, 2H, CH2), 2.44-2.46 (m, 6H, 3×CH2), 3.51-3.522
(m, 2H, CH2), 3.72-3.74 (m, 4H, 2×CH2), 5.27 (s, 2H, CH2), 5.52 (s, 2H, CH2), 6.98-7.01 (m,
2H, H6, H8), 7.22 (d, J = 7.0 Hz, 2H, H2ʹ, H6ʹ), 7.36 (d, J = 7.0 Hz, 2H, H3ʹ, H5ʹ), 7.57 (d, J =
7.5 Hz, 1H, H5), 8.82-8.90 (m, 3H, triazole, H4, NH). 13C NMR (125 MHz, CDCl3): 25.1, 38.2,
53.6, 53.8, 56.6, 62.5, 66.9, 95.5, 101.5, 112.9, 114.1, 115.4, 115.7, 122.8, 129.5, 131.0, 135.1,
143.1, 148.1, 156.4, 161.6, 161.9, 163.1. Anal. calcd. for C27H28ClN5O5: C, 60.28; H, 5.25; N,
13.02. Found: C, 60.11; H, 5.41; N, 12.87.
4.1.17 7-((1-(3-Chlorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11q)
Yield: 65%, white solids, mp 195-196 oC. IR (KBr): 3346, 3091, 2941, 2806, 1716, 1610, 1532.
1H NMR (500 MHz, CDCl3): 1.80-1.82 (m, 2H, CH2), 2.45-2.46 (m, 6H, 3×CH2), 3.52-3.53 (m,
2H, CH2), 3.72-3.73 (m, 4H, 2×CH2), 5.29 (s, 2H, CH2), 5.53 (s, 2H, CH2), 6.98-7.01 (m, 2H,
H6, H8), 7.17 (d, J = 7.0 Hz, 1H, H6ʹ), 7.31-7.34 (m, 2H, H4ʹ, H5ʹ), 7.58 (d, J = 8.5 Hz, 1H,
19

H5), 7.62 (s, 1H, H2ʹ), 8.70-8.90 (m, 3H, triazole, H4, NH). 13C NMR (125 MHz, CDCl3)/(two
isomers probably due to delocalization of lone pair on the nitrogen): 26.0, 38.2, 53.6, 53.8, 56.6,
62.5, 66.9, 100.9, 101.5, 112.9, 113.3, 114.1, 115.3, 123.0, 126.1, 128.0, 128.2, 129.1, 129.5,
130.5, 131.0, 135.1, 136.2, 143.2, 147.9, 148.1, 156.4, 161.2, 162.9. Anal. calcd. for
C27H28ClN5O5: C, 60.28; H, 5.25; N, 13.02. Found: C, 60.44; H, 5.15; N, 13.2.
4.1.18. 7-((1-(4-Fluorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11r)
o
Yield: 75%, white solids, mp 171-173 C. IR (KBr): 3340, 2918, 2820, 1710, 1655, 1610, 1565
cm-1. 1H NMR (500 MHz: DMSO-d6): 1.68 (quintet, J = 6.5 Hz, 2H, CH2), 2.33-2.36 (m, 6H, 3
× CH2), 3.36 (t, J = 6.5 Hz, 2H, CH2), 3.57-3.59 (m, 4H, 2×CH2), 5.31 (s, 2H, CH2), 5.62 (s,
2H, CH2), 7.10 (dd, J = 8.5, 2.5 Hz, 1H, H6), 7.22 (t, J = 8.0 Hz, 2H, H3', H5'), 7.27 (d, J = 2.5
Hz, 1H, H8), 7.41 (dd, J = 8.0, 5.5 Hz, 2H, H2', H6'), 7.90 (d, J = 8.5 Hz, 1H, H5), 8.35 (s, 1H,
triazole), 8.76 (t, J = 5.5 Hz, 1H, NH), 8.83 (s, 1H, H4). 13C NMR (125 MHz: DMSO-d6): 25.6,
38.1, 52.1, 53.4, 56.1, 61.9, 66.1, 95.5, 101.1, 112.6, 114.0, 115.6 (d, JC-F = 21.5 Hz), 125.0,
130.3 (d, JC-F = 7.5 Hz), 131.5, 133.5, 142.1, 147.7, 156.1, 160.5, 161.2, 162.9. 163.1 (d, JC-F
=
245.0 Hz). Anal. calcd. for C27H28FN5O5: C, 62.18; H, 5.41; N, 13.43. Found: C, 62.29; H, 5.64;
N, 13.59.
4.1.19. 7-((1-(3-Fluorobenzyl)-1H-1,2,3-triazol-4-yl)methoxy)-N-(3-morpholinopropyl)-2-oxo-
2H-chromene-3-carboxamide (11s)
o
Yield: 70%, white solids, mp 201-202 C. IR (KBr): 3348, 3063, 2926, 2856, 1715, 1611, 1532
1
cm-1. H NMR (500 MHz, CDCl3): 1.8-1.83 (m, 2H, CH2), 2.47-249 (m, 6H, 3×CH2), 3.52 (m,
2H, CH2), 3.35-375 (m, 4H, 2×CH2), 5.28 (s, 2H, CH2), 5.55 (s, 2H, CH2), 6.98-7.59 (m, 7H,
H5, H6, H8, H2ʹ, H4ʹ, H5ʹ, H6ʹ), 8.81-8.89 (m, 3H, triazole, H4, NH). 13C NMR (125 MHz,
DMSO-d6): 29.7, 38.2, 53.0, 53.7, 56.6, 62.5, 66.7, 95.7, 101.5, 112.6, 114.0, 114.4 (d, JC-F
=
22.1 Hz), 115.6 (d, JC-F = 21.5 Hz), 125.2, 130.8 (d, JC-F = 7.5 Hz), 131.0, 132.0, 133.5, 142.0,
20

147.5, 156.1, 160.3, 161.2, 162.8. 163.2 (d, JC-F = 247.0 Hz). Anal. calcd. for C27H28FN5O5: C,
62.18; H, 5.41; N, 13.43. Found: C, 61.91; H, 5.18; N, 13.21.
4.2. In vitro AChE/BChE inhibition assay
The anti-cholinesterase activity of target compounds 11 was assessed in vitro against
AChE from Electrophorus electricus (eel AChE) and horse serum butyrylcholinesterase (eq
BChE) by using the spectrophotometric Ellman’s method [32]. In order to obtain a range of 20-
80% enzyme inhibition, five different concentrations of each compound were tested. A mixture
of phosphate buffer (0.1 mol/L-1, pH 8.0, 3 mL), 5,5′-dithio-bis(2-nitrobenzoic acid) (DTNB,
100 μL), acetylcholinesterase or butyrylcholinesterase (100 μL, 2.5 IU/mL) and compound
solution (100 μL) was pre-incubated for 10 min. Then, the substrate (acetylthiocholine iodide or
butyrylthiocholine iodide) was added. In parallel, a blank containing all components without
enzyme was used in order to account the non-enzymatic reaction. Changes in absorbance were
measured at 412 nm for 6 min at 25 °C by using an UV Unico Double Beam spectrophotometer.
The IC50 values were determined graphically from log concentration vs. % of inhibition curves.
All experiments were performed in triplicate
4.3. Β-Secretase inhibitory activity
β-Secretase inhibitory activity of compound 11b was performed according to our
previous report using a FRET-based assay kit, from Invitrogen (former Pan Vera, Madison, WI)
comparing with OM99 was used as a reference inhibitor agent [19,31]. Stock solution of
compound 11b was prepared by solving that in DMSO and diluted with the assay buffer (50 mM
sodium acetate; pH 4.5). 10 µL of BACE1 substrate (Rh-EVNLDAEFK-Quencher) was mixed
with 10 µL of the tested compound and then 10 µL of enzyme (1 U/mL) was added to initiate the
reaction. After 90 min of incubation at room temperature, 10 µL sodium acetate (2.5 M) was
used to stop the reaction. The fluorescence was monitored at 545 nm (Ex) and 585 nm (Em). The
experiment was achieved in triplicate for each concentration in 96-well polystyrene black plates.
21

4.4. Neuroprotectivity assay
PC12 cell line was obtained from Pasteur institute and they were cultivated in DMEM
supplemented with 10% fetal calf serum, 5% horse, and antibiotics (100 units/mL penicillin, 100
μg/mL streptomycin). All culture media and supplements were purchased from Gibco. To induce
neuronal differentiation, PC12 cells were re-suspended using trypsin/EDTA (0.25% ) and seeded
in 96 well culture plate (3000 cells/well) and cultured for 1 week in differentiation medium
(DMEM + 2% horse serum + NGF (100 ng/mL) + penicillin & streptomycin). To evaluate the
effect of drugs on survival rate of neurons, the culture medium was changed to NGF free
medium and different concentrations of candidate drugs (10, 50, and 100 μM) were applied on
cells. Quercetin (50 μM) was used as a positive control. Compound 11b was diluted in DMEM
and 10 µL of that solution added to each well. After 3 h, induction of ROS-mediated apoptosis
was initiated by adding the H2O2 (400 μM) to their medium and after 12 h, MTT assay was
performed. For this purpose, 10 µL of MTT solution (5 mg/mL) was added to each well and after
3 h, culture medium was replaced by 100 μL of DMSO. Absorbance was measured at 545 nm for
each well using an ELISA reader. Each experiment was performed in four replicates.
4.5. Metal chelating
All solutions used in metal-chelating study were prepared in methanol and Fe2+, Cu2+,
and Zn2+ solutions were prepared from FeSO4, CuCl2 or and ZnCl2 respectively.
To study the metal binding ability, a mixture of compound 11b (1 mL) and metal solution (1 mL)
with the same concentration (20 µM) in a 1 cm quartz cuvette was incubated at room temperature
for 30 min. Then, the absorption spectra were recorded with wavelength ranging from 200–500
nm. The stoichiometry of complex 11b-Zn2+ was also studied using the molar ratio method [35].
The concentration of tested compound 11b was 20 μM and the final concentration of Zn2+ ranged
from 0-100 μM at 347 nm. The plot was obtained by the corresponding absorption versus mole
fraction of Zn2+.
22

4.6. Docking simulations
The program docking simulations was performed using Autodock Vina [36]. The crystal
structure of Torpedo californica acetylcholinesterase (1EVE) was obtained from Protein Data
Bank (http://www.rcsb.org/pdb/home/home.do). To provide receptor and ligand structures for
the related studies, the following procedure was performed. First, the co-crystallized
ligand and water molecules were removed from the protein. Then, atomic coordinates of the
ligands was prepared using Marvinsketch, 2012, ChemAxon (http://www.chemaxon.com), the
3D structures were constructed using Openable [37]. Next, the receptor and optimized structure
of the ligands were converted to required pdbqt format using Autodock Tools [38]. The
Autodock Vina parameters were set as follow; box size: 15×15×15 Å, the center of box: x
= 2.023, y = 63.295, z = 67.062 (geometrical center of co-crystallized ligand), the
exhaustiveness: 100, and the remaining parameters were left unchanged. The calculated
geometries were ranked in terms of free energy of binding and the best poses were selected for
further analysis. All molecular visualizations were carried out in DS Viewer Pro (Accelrys,
Inc., San Diego, CA).
Acknowledgments
This work was supported by grants from the Research Council of Tehran University of
Medical Sciences with project No. 94-03-96-30244.
Reference
[1] B.L. Plassman, K.M. Langa, G.G. Fisher, S.G. Heeringa, D.R. Weir, M.B. Ofstedal, J.R.
Burke, M.D. Hurd, G.G. Potter, W.L. Rodgers, D.C. Steffens, R.J. Willis, R.B. Wallace,
Prevalence of dementia in the United States: the aging, demographics, and memory
study, Neuroepidemiology 29 (2007) 125-132.
23

[2] H. Oakley, S.L. Cole, S. Logan, E. Maus, P. Shao, J. Craft, A. Guillozet-Bongaarts, M.
Ohno, J. Disterhoft, L. Van Eldik, R. Berry, R. Vassar. Intraneuronal β-amyloid
aggregates, neurodegeneration, and neuron loss in transgenic mice with five familial
Alzheimer's disease mutations: potential factors in amyloid plaque formation, J.
Neurosci. 26 (2006) 10129-10140.
[3] F.M. LaFerla, K.N. Green, S. Oddo, Intracellular amyloid-β in Alzheimer's disease,
Nature Rev. Neurosci. 8 (2007) 499-509.
[4] A.I. Bush, The metal theory of Alzheimer's disease, J. Alzheimers Dis. 33 Suppl 1
(2013) S277-281.
[5] A. Robert, Y. Liu, M. Nguyen, B. Meunier, Regulation of c and iron homeostasis by
metal chelators: a possible chemotherapy for Alzheimer’s disease, Acc. Chem. Res. 48
(2015) 1332-1339.
[6] M.P. Mattson, K.J. Tomaselli, R.E. Rydel. Calcium-destabilizing and neurodegenerative
effects of aggregated beta-amyloid peptide are attenuated by basic FGF, Brain Res. 621
(1993) 35-49.
[7] D. Di Bona, G. Scapagnini, G. Candore, L. Castiglia, G. Colonna-Romano, G. Duro, D.
Nuzzo, F. Iemolo, D. Lio, M. Pellicanò, V. Scafidi, C. Caruso, S. Vasto, Immune-
inflammatory responses and oxidative stress in Alzheimer's disease: therapeutic
implications, Curr. Pharm. Des. 16 (2010) 684-691.
[8] T.H. Ferreira-Vieira, I.M. Guimaraes, F.R. Silva, F.M. Ribeiro, Alzheimer's disease:
targeting the sholinergic system, Curr. Neuropharmacol. 14 (2016) 101-115.
[9] P. Talaga, β-Amyloid aggregation inhibitors for the treatment of Alzheimer’s disease:
dream or reality, Mini Rev. Med. Chem. 1 (2001) 175-186.
24

[10]
A. Castro, A. Martinez, Inhibition of tau phosphorylation: a new
therapeutic strategy for the treatment of Alzheimer’s disease and other, Expert Opin.
Ther. Pat. 10 (2000) 1519-1527.
[11]
D.G. Wilkinson, P.T. Francis, E. Schwam, J. Payne-Parrish,
Cholinesterase inhibitors used in the treatment of Alzheimer’s disease, Drugs Aging 21
(2004) 453-478.
[12]
I. Wessler, C.J. Kirkpatrick, Acetylcholine beyond neurons: the non-
neuronal cholinergic system in humans, Br. J. Pharmacol. 154 (2008) 1558-1571.
[13]
C. Bartolucci, L.A. Haller, U. Jardis, G. Fels, D. Lamba, Probing
Torpedo californica acetylcholinesterase catalytic gorge with two novel bis-functional
galanthamine derivatives, J. Med. Chem. 53 (2010) 745-751.
[14]
present), Expert Opin. Ther. Pat. 22 (2012) 1354-3776.
[15] P. Gabrielle, M. Jeana, E.C. Lorenza. Cytosolic choline
M. Pohanka, Acetylcholinesterase inhibitors: a patent review (2008-
acetyltransferase binds specifically to cholinergic plasma membrane of rat brain
synaptosomes to generate membrane-bound enzyme, Neurochem. Res. 28 (2003) 543-
549.
[16]
S. Gupta, C.G. Mohan, 3D-Pharmacophore model based virtual
screening to identify dual-binding site and selective acetylcholinesterase inhibitors,
Med. Chem. Res. 20 (2011) 1422-1430.
[17]
for treatment, Neurotox. Res. 2 (2000) 157-165.
[18] L.A. Craiga, N.S. Honga, R.J. McDonald, Revisiting the cholinergic
A. Nordberg, Neuroprotection in Alzheimer's disease - new strategies
hypothesis in the development of Alzheimer’s disease, Neurosci. Biobehav. Rev. 35
(2011) 1397–1409.
25

[19]
M. Saeedi, M. Safavi, E. Karimpour-Razkenari , M. Mahdavi , N.
Edraki, F.H. Moghadam, M. Khanavi, T. Akbarzadeh, Synthesis of novel chromenones
linked to 1,2,3-triazole ring system: Investigation of biological activities against
Alzheimer’s disease, Bioorg. Chem. 70 (2017) 86–93.
[20]
M. Saeedi, M. Golipoor, M. Mahdavi, A. Moradi, H. Nadri, S. Emami,
A. Foroumadi, A. Shafiee, Phthalimide‐ Derived N‐ benzylpyridinium halides targeting
cholinesterases: synthesis and bioactivity of new potential anti‐ Alzheimer's disease
agents, Arch. Pharm. 349 (2016) 293-301.
[21]
Z. Najafi, M. Mahdavi, M. Saeedi, E. Karimpour-Razkenari, Raymond
Asatouri, Fahimeh Vafadarnejad, Farshad Homayouni Moghadam, M. Khanavi, M.
Sharifzadeh, T. Akbarzadeh, Novel tacrine-1,2,3-triazole hybrids: in vitro, in vivo
biological evaluation and docking study of cholinesterase inhibitors, Eur. J. Med. Chem.
125 (2017) 1200-1212.
[22]
Z. Najafi, M. Saeedi, M. Mahdavi, R. Sabourian, M. Khanavi, M. B.
Tehrani, F.H. Moghadam, N. Edraki, E. Karimpor-Razkenari, M. Sharifzadeh, A.
Foroumadi, A. Shafiee, T. Akbarzadeh, Design and synthesis of novel anti-Alzheimer’s
agents: Acridine-chromenone and quinoline-chromenone hybrids. Bioorg. Chem. 67
(2016) 84-94.
[23]
B. Sameem, M. Saeedi, M. Mahdavi, H. Nadri, F.H. Moghadam, N.
Edraki, M.I. Khan, M. Amini, Synthesis, docking study and neuroprotective effects of
some novel pyrano[3,2-c]chromene derivatives bearing morpholine/phenylpiperazine
moiety, Bioorg. Med. Chem. 25 (2017) 3980-3988.
[24]
R. Hariri, Z. Afshar, M. Mahdavi, M. Safavi, M. Saeedi, Z. Najafi, R.
Sabourian, E. Karimpour‐ Razkenari, N. Edraki, F.H. Moghadam, A. Shafiee, M.
Khanavi,
T.
Akbarzadeh,
Novel
tacrine‐ based
26

pyrano[3’,4’:5,6]pyrano[2,3‐ b]quinolinones: synthesis and cholinesterase inhibitory
activity, Arch. Pharm. 349 (2016) 915-924.
[25]
P. Anand, B. Singh, N. Singh, A review on coumarins as
acetylcholinesterase inhibitors for Alzheimer’s disease, Bioorg. Med. Chem. 20 (2012)
1175-1180.
[26]
S. Marumoto, M. Miyazawa, Structure–activity relationships for
naturally occurring coumarins as β-secretase inhibitor, Bioorg. Med. Chem. 20 (2012)
784-788.
[27]
W.G. Lewis, L.G. Green, F. Grynszpan, Z. Radić, P.R. Carlier, P.
Taylor, M.G. Finn, K.B. Sharpless, Click chemistry in situ: acetylcholinesterase as a
reaction vessel for the selective assembly of a femtomolar inhibitor from an array of
building blocks, Angew. Chem. Int. Ed. 41 (2002) 1053-1057.
[28]
S.K. Mamidyala, M.G. Finn, In situ click chemistry: probing the
binding landscapes of biological molecules, Chem. Soc. Rev. 39 (2010) 1252-1261.
[29]
R. Hoerr, M. Noeldner, Ensaculin (KA-672-HCl): a multitransmitter approach to
dementia treatment, CNS Drug Rev. 8 (2002) 143-158.
[30]
A. Asadipour, M. Alipour, M. Jafari, M. Khoobi, S. Emami, H. Nadri, A.
Sakhteman, A. Moradi, V. Sheibani, F.H. Moghadam, A. Shafiee, A. Foroumadi, Novel
coumarin-3-carboxamides
acetylcholinesterase inhibitors, Eur. J. Med. Chem. 70 (2013) 623-670.
[31] A. Iraji, O. Firuzi, M. Khoshneviszadeh, M. Tavakkoli, M. Mahdavi, H. Nadri,
bearing
N-benzylpiperidine
moiety
as
potent
N. Edraki, R. Miri, Multifunctional iminochromene-2H-carboxamide derivatives
containing different aminomethylene triazole with BACE1 inhibitory, neuroprotective
and metal chelating properties targeting Alzheimer's disease. Eur. J. Med. Chem. 141
(2017) 690-702.
27

[32]
G.L. Ellman, K.D. Courtney, V. Andres Jr., R.M. Feather-Stone, A new and
rapid colorimetric determination of acetylcholinesterase activity, Biochem. Pharmacol.
71 (1961) 88–95.
[33]
M. Saeedi, S. Ansari, M. Mahdavi, R. Sabourian, T. Akbarzadeh, A. Foroumadi,
A. Shafiee, Synthesis of novel 1,2,3-triazole-dihydro[3,2-c]chromenones as
acetylcholinesterase inhibitors, Synth. Commun. 45 (2015) 2311-2318.
[34]
C. Rodríguez-Rodríguez, M. Telpoukhovskaia, C. Orvig, The art of building
multifunctional metal-binding agents from basic molecular scaffolds for the potential
application in neurodegenerative diseases, Coord. Chem. Rev. 256 (2012) 2308-2332.
[35]
X. Qiang, Z. Sang, W. Yuan, Y. Li, Q. Liu, P. Bai, Y. Shi, W. Ang, Z. Tan, Y.
Deng, Design, synthesis and evaluation of genistein-O-alkylbenzylamines as potential
multifunctional agents for the treatment of Alzheimer’s disease, Eur. J. Med. Chem. 76
(2014) 314-331.
[36]
O. Trott, A.J. Olson, AutoDock Vina: improving the speed and accuracy of
docking with a new scoring function, efficient optimization , and multithreading, J.
Comput. Chem. 31 (2010) 455-461.
[37]
N.M. O’Boyle, M. Banck, C.A. James, C. Morley, T. Vandermeersch, G.R.
Hutchison, Open Babel: An open chemical toolbox, J. Cheminform, 3 (2011) 33.
[38]
M.F. Sanner, A programming language for softwa re integration and
development, J. Mol. Graph. Model. 17 (1999) 57-61.
28

Scheme 1. Synthesis of 1,2,3-triazole-chromenone carboxamides 11.
29