Design, synthesis, acetylcholinesterase inhibition and larvicidal activity of girgensohnine analogs on Aedes aegypti, vector of dengue fever

Article abstract of DOI:10.1016/j.ejmech.2014.03.067

Girgensohnine alkaloid was used as a natural model in the design and generation of new alkaloid-like α-aminonitrile series that was completed by the use of SSA-catalyzed Strecker reaction between commercial and inexpensive substituted benzaldehydes, piperidine (pyrrolidine, morpholine and N-methylpiperazine) and acetone cyanohydrin. Calculated ADMETox parameters of the designed analogs revealed their good pharmacokinetic profiles indicating lipophilic characteristics. In vitro AChE enzyme test showed that obtained α-aminonitriles could be considered as AChEIs with micromolar IC ₅₀ values ranging from 42.0 to 478.0 μM (10.3-124.0 μg/mL). Among this series, the best AChE inhibitor was the pyrrolidine α-aminonitrile 3 (IC₅₀ = 42 μM), followed by the piperidine α-aminonitriles 2 and 6 (IC₅₀ = 45 μM and IC₅₀ = 51 μM, respectively), and the compound 7 (IC₅₀ = 51 μM). In vivo insecticidal activity of more active AChEIs against Aedes aegypti larvae was also performed showing a good larvicidal activity at concentrations less than 140 ppm, highlighting products 2 and 7 that could serve as lead compounds to develop new potent and selective insecticides.

Full text of DOI:10.1016/j.ejmech.2014.03.067

European Journal of Medicinal Chemistry 78 (2014) 392e400
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Design, synthesis, acetylcholinesterase inhibition and larvicidal
activity of girgensohnine analogs on Aedes aegypti, vector of
dengue fever
Aurora L. Carreño Otero a, Leonor Y. Vargas Méndez b, Jonny E. Duque L. c,
,
Vladimir V. Kouznetsov a
*
a Laboratorio de Química Orgánica y Biomolecular, Escuela de Química, Universidad Industrial de Santander, Bucaramanga A.A. 678, Colombia
b Grupo de investigaciones Ambientales para el Desarrollo Sostenible, Universidad Santo Tomás de Aquino, Bucaramanga A.A. 678, Colombia
c Centro de Investigaciones en Enfermedades Tropicales y Grupo de Investigación en Enfermedades Infecciosas y Metabólicas, Escuela de Medicina,
Universidad Industrial de Santander, Bucaramanga A.A. 678, Colombia
a r t i c l e i n f o
a b s t r a c t
Article history:
Girgensohnine alkaloid was used as a natural model in the design and generation of new alkaloid-like
Received 21 August 2013
Received in revised form
30 January 2014
Accepted 22 March 2014
Available online 24 March 2014
a-aminonitrile series that was completed by the use of SSA-catalyzed Strecker reaction between com-
mercial and inexpensive substituted benzaldehydes, piperidine (pyrrolidine, morpholine and N-meth-
ylpiperazine) and acetone cyanohydrin. Calculated ADMETox parameters of the designed analogs
revealed their good pharmacokinetic profiles indicating lipophilic characteristics. In vitro AChE enzyme
test showed that obtained
ranging from 42.0 to 478.0
a
m
-aminonitriles could be considered as AChEIs with micromolar IC50 values
M (10.3e124.0 g/mL). Among this series, the best AChE inhibitor was the
M), followed by the piperidine -aminonitriles 2 and 6
M, respectively), and the compound 7 (IC50 ¼ 51 M). In vivo insecticidal
m
Keywords:
pyrrolidine
(IC50 ¼ 45
a
-aminonitrile 3 (IC50 ¼ 42
m
a
a
-Aminonitriles
m
M and IC50 ¼ 51
m
m
Strecker reaction
AChE inhibition
Larvicidal activity
Aedes aegypti larvae
activity of more active AChEIs against Aedes aegypti larvae was also performed showing a good larvicidal
activity at concentrations less than 140 ppm, highlighting products 2 and 7 that could serve as lead
compounds to develop new potent and selective insecticides.
Ó 2014 Elsevier Masson SAS. All rights reserved.
1. Introduction
most methods for A. aegypti mosquitoes control rely on the use of
chemical insecticides, mainly belonging to the organophosphate,
Vector-borne infectious viral diseases, transmitted to human by
the bite of arthropod vectors constitute a significant proportion of
the global infectious disease burden. Among many arthropods,
diverse and numerous insects mosquitoes are a major public health
problem as vectors of serious human diseases like malaria, filari-
asis, dengue fever, dengue hemorrhagic fever and yellow fever.
Aedes aegypti mosquitoes are the major vector of dengue fever, an
endemic disease in America and Asia and represent a serious threat
worldwide in terms of public health affecting 40e80 million people
every year [1]. Dengue virus belongs to the Flavivirus genus of the
Flaviviridae family and is primarily transmitted by Aedes mosqui-
toes. In the absence of specific antiviral drugs or efficient vaccine,
the A. aegypti control methods are therefore critical [2,3]. However,
carbamate and pyrethroid classes. Subsequently, resistance of
mosquito populations to these chemicals is increasing at a dramatic
rate, threatening the efficacy of any control methods. According to
these facts, there is a continuous need to explore new active mol-
ecules with different mechanisms of action [4e8].
Among diverse mechanisms of action, the insect enzyme
acetylcholinesterase (AChE) inhibition stands out a promise in-
secticides control method. Inhibitors of this type of mechanism (for
ex., organophosphate and carbamate chemicals) affect the trans-
mission of nerve impulses accumulating acetylcholine in neuro-
muscular tissue of insects causing paralysis and then death [7].
Therefore, the discovery of insect AChE inhibitors (AChEIs) is an
important task [9,10] where insecticide design based on natural
molecule findings play a key role.
So, with these facts in mind and as a part of our medicinal
research program directed to the development of small molecule
* Corresponding author.
E-mail addresses: kouznet@uis.edu.co, vkuznechnik@gmail.com (V.V. Kouznetsov).
http://dx.doi.org/10.1016/j.ejmech.2014.03.067
0223-5234/Ó 2014 Elsevier Masson SAS. All rights reserved.

A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
393
2. Results and discussion
2.1. Chemistry
In this study, for new girgensohnine analogs obtaining we chose
easily the Strecker reaction that provides diverse -aminonitriles in
a
an efficient manner using aromatic aldehydes, amines (mainly,
cyclic secondary amines) and a cyanide source [14]. A rich set of
aromatic aldehydes and cyclic secondary amines is available from
different chemical companies and varying them it could be
Fig. 1.
a-Aminonitriles design inspired by natural molecule, girgensohnine alkaloid.
drug discovery, we started preliminary study on this topic paying
attention to an infrequent structure of girgensohnine alkaloid
(Fig. 1). The girgensohnine 1, racemic product is a cyanogenic
metabolite extracted with a yield of no more than 0.05% from Gir-
gensohnia oppositiflora (Amaranthaceae), shrub that grows in the
Russia and Iran deserts [11]. This is one of the unusual cases of
cyanogenic compounds with a piperidine ring without a glycosidic
linkage in their core structure [12]. Although their structural
elucidation and synthesis were reported in 1946, there was not
mention in the literature about its bioactivities until our pre-
liminary work [13]. The scarcity of this alkaloid in the natural
source, unknown biological properties and at the same time their
simple structure, all this was motivated to undertake this study of
obtaining new similar molecules with insecticidal activity, which
generated numerous
However, we limited our possible reagents list to six benzalde-
hydes (4-hydroxybenzaldehyde, 4-hydroxy-3-methoxy-
a-aminonitriles.
benzaldehyde,
dimethoxybenzaldehyde,
3-hydroxy-4-methoxybenzaldehyde,
3,4-
and
3,4,5-trimethoxybenzaldehyde
piperonal) and four cyclic secondary amines (piperidine, pyrroli-
dine, morpholine and N-methylpiperazine) based on in silico ADME
profiles evaluation of new 24
a-aminonitriles, close analogs of
girgensohnine alkaloid. So, prior to synthetizing desired molecules,
their physico-chemical parameters were evaluated, employing the
Lipinski’s rule [15e17]. It should be noted that these types of
physicochemical parameters and some additional (topological po-
lar surface area, number of rotatable bonds, water solubility, and
dissociation constant, etc.) have proven useful for predicting the
biological properties not only new pharmacological agents, but also
new agrochemical substances [18,19]. The obtained results showed
belong to an
According to the accounts described above, our study focused
in: i) design -aminonitriles from girgensohnine structure; ii)
a-aminonitrile chemical class of compounds (Fig. 1).
a
determine and analyze their in silico ADME properties, based on the
Lipinski’s rule; iii) prepare a small library of new girgensohnine
alkaloid analogs (a-aminonitriles); iv) estimate in vitro AChE inhi-
bition of the obtained molecules, and v) evaluate in vivo insecticidal
activity against A. aegypti larvae of the most active molecules in
AChE inhibition process. All this, are in order to contribute in lead
compounds identification to develop new potent and selective in-
that the proposed
a-aminonitriles 1-24 including girgensohnine
alkaloid have pharmacokinetic profiles, and fulfill all parameters
established by this rule (molecular weight ¼ 202.03e305.37,
logP ¼ 0.71e2.22, nON ¼ 2e6, and nOHNH ¼ 0e4) (Table 1). In
general, it can be seen that the a-aminonitriles 1-24 are lipophilic
molecules showing clogP values below 2.5.
Next, planning their preparation, we had to select cyanide
sources and catalysts to perform three-component Strecker reac-
tion. Regarding these aspects, this reaction has been studied
secticides based on this
sohnine structure.
a-aminonitrile class inspired by girgen-
Table 1
Calculated physico-chemical parameters for proposed
a
-aminonitriles 1e24.
H-bond acceptor
ꢀ10
2
ꢀ
Molecules
MW
H-bond donor
LogP, average
TPSA A
NER
LogS average
pKa
ꢀ500
ꢀ5
ꢀ5
ꢀ140
ꢀ10
ꢁ ꢂ4.0
1
2
3
4
5
6
7
8
216.2
260.3
246.3
262.3
275.3
244.2
230.2
246.2
259.3
290.4
276.3
292.3
305.4
246.3
232.3
248.3
261.3
246.3
232.3
248.3
261.3
202.3
218.3
231.3
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
3
4
4
5
5
4
4
5
5
5
5
6
6
4
4
5
5
4
4
5
5
3
4
4
2.09 (ꢃ0.38)
2.22 (ꢃ0.52)
1.82 (ꢃ0.47)
0.94 (ꢃ0.54)
1.05 (ꢃ0.57)
0.97 (ꢃ0.46)
1.87 (ꢃ0.43)
0.97 (ꢃ0.41)
1.09 (ꢃ0.46)
2.10 (ꢃ0.61)
1.70 (ꢃ0.56)
0.83 (ꢃ0.62)
0.94 (ꢃ0.66)
1.98 (ꢃ0.48)
1.60 (ꢃ0.44)
0.71 (ꢃ0.51)
0.83 (ꢃ0.55)
1.99 (ꢃ0.48)
1.60 (ꢃ0.44)
0.71 (ꢃ0.51)
0.83 (ꢃ0.55)
1.68 (ꢃ0.37)
0.80 (ꢃ0.43)
0.94 (ꢃ0.50)
47.26
45.49
45.49
54.72
48.73
45.49
45.49
54.72
48.73
54.72
54.72
63.95
57.96
56.49
56.49
65.72
59.73
56.49
56.49
65.72
59.73
47.26
56.49
50.50
3
5
5
5
5
3
3
3
3
6
6
6
6
4
4
4
4
4
4
4
4
3
3
3
ꢂ2.0
ꢂ2.8
ꢂ2.3
ꢂ1.9
ꢂ1.5
ꢂ2.6
ꢂ2.3
ꢂ1.9
ꢂ1.6
ꢂ2.9
ꢂ2.5
ꢂ2.0
ꢂ1.7
ꢂ2.2
ꢂ1.8
ꢂ1.4
ꢂ1.1
ꢂ2.2
ꢂ1.8
ꢂ1.4
ꢂ1.1
ꢂ1.6
ꢂ1.2
ꢂ1.0
4.2 ꢃ 0.4
4.0 ꢃ 0.4
4.3 ꢃ 0.4
2.2 ꢃ 0.5
7.6 ꢃ 0.4
4.0 ꢃ 0.4
4.3 ꢃ 0.4
2.2 ꢃ 0.5
7.6 ꢃ 0.4
3.9 ꢃ 0.4
4.2 ꢃ 0.4
2.1 ꢃ 0.5
7.6 ꢃ 0.4
4.0 ꢃ 0.4
4.3 ꢃ 0.4
2.2 ꢃ 0.5
7.7 ꢃ 0.4
4.1 ꢃ 0.4
4.4 ꢃ 0.4
2.3 ꢃ 0.5
7.7 ꢃ 0.4
4.5 ꢃ 0.4
2.4 ꢃ 0.5
7.7 ꢃ 0.4
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
MW: Molecular weight (g/mol); H-bond donor: hydrogen bond donors (expressed as the sum of OHs and NHs); H-bond acceptor: hydrogen bond acceptors (expressed as the
sum of Ns and Os); cLogP: n-octanolewater partition coefficient; TPSA: topological polar surface area; NER: number of rotatable bonds; LogS: aqueous solubility; pKa:
dissociation constant.

394
A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
Scheme 1. Preparation of girgensohnine analogs 1e24.
extensively by using different Lewis acids [20e22] or bases [23,24],
and metalesalen complexes [25] as catalysts, and NaCN, KCN, tri-
methylsilyl cyanide, acetone cyanohydrin (AC) as main cyanide
sources. Furthermore, catalyst-free and promoted-sulfuric acid
supported on silica gel (SSA) three-component Strecker reactions
were reported [26,27], while first syntheses of the girgensohnine
were performed using KCN/NaHCO3/H2O (56% yields) system [11]
and NaCN/5% mol InCl3/MeCN (76% yields) system [13]. Addition-
ally, SSA catalyst is recoverable and reusable material with easy
handling, low toxicity and wide range of solvent tolerance and
acetone cyanohydrin is considered as available, cheap, safe and
green organic cyanide source. With this background and in search
for the most safe and environmentally friendly protocol to prepare
the desired compounds, we considered that AC and SSA should be a
good choice of appropriated reaction conditions for planned three-
component Strecker reactions. However, to compare the chosen
green AC/SSA protocol (method A), classical inorganic cyanide
source KCN in presence of SSA (KCN/SSA protocol, method B) was
also used in our investigation. Both synthetic protocols were per-
formed in MeCN at room temperature over 16e24 h.
[30,31]. Analyzing the biochemical data consigned in Table 3, it is
reasonable safe to suggest that AChE inhibitory activity depends
considerably on chemical nature of both substituents on aryl
moieties and cyclic aminyl fragments in
was found that all obtained molecules are considered as AChEIs
with micromolar IC50 values ranging from 42.0 to 478.0 M (10.3e
124.0 g/mL) noting that the inclusion of two electron-donating
group methoxy or dioxymethylen ring on the aryl fragments in
aminonitriles 2e4 and 6e8 (but not in -aminonitriles 5,9)
a-aminonitrile structure. It
m
m
a
-
a
improved significantly AChE inhibition comparing with the gir-
gensohnine alkaloid 1 activity that showed moderate AChE inhi-
bition (IC50 ¼ 93
AChE inhibitory activity of the rest molecules 5, 9e21. Among this
series, the best AChE inhibitor was the pyrrolidine -aminonitrile 3
-aminonitriles 2 and 6
M, respectively), and the compound 7
M). Surprisingly, it was found that the series of the a-
mM), less than its analogs 2-4,6-8 and similar to
a
(IC50 ¼ 42
(IC50 ¼ 45
(IC50 ¼ 51
m
M), followed by the piperidine
a
m
m
M and IC50 ¼ 51
m
aminonitriles 10e21 with 3,4,5-trimethoxy- and 4-hydroxy-3-
methoxy- or 3-hydroxy-4-methoxy-aryl moieties did not show
appreciable activity and the series of the N-methylpiperazine
aminonitriles 5,9,13,17 and 21 resulted worse AChEIs (IC50 ¼ 340.2e
475.0 M).
a-
Thus, by selected and justified reaction conditions, racemic
aminonitriles 1e13 including girgensohnine alkaloid were syn-
thesized following by the method A procedure, while -amino-
a-
m
a
Thus, it can conclude that modifications in the size and type of
nitriles 14e21 with 4-hydroxy-3-methoxy- or 3-hydroxy-4-
methoxy-aryl moieties were obtained using reaction conditions
of the method B (Scheme 1); only three designed molecules 22e24
could not be prepared under reaction conditions of both synthetic
protocols [28].
nitrogen heterocycles as well as the inclusion of electron-donating
groups (MeO) on the aryl fragments in a-aminonitrile structures
influenced considerably in vitro AChE inhibition and consequently,
could be affected in vivo insecticide activity. Finally, we attempted
In general, all molecules 1e21 were prepared with moderate to
excellent yields presenting the well-defined melting points
(Table 2).
Structural elucidation of the obtained molecules 1e21 was
made using diverse spectroscopic techniques (FT-IR, GC-EM, 1H
NMR and 13C NMR) that identify easily main spectral features
Table 2
SiO2eOSO3H catalyzed the Strecker reaction of heterocyclic amines and aldehydes
for synthesis of 1e24.
Comp. R1
R2
R3
X
n
Mp, ꢄC
Yield, %
Method A Method B
(group CN,
a cyano group hydrogen, aromatic and N-heterocyclic
1
2
3
4
5
6
7
8
H
H
H
H
H
H
H
H
H
HO
MeO
MeO
MeO
H
CH2
1
1
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
0
1
1
115e117 73
68
72
56
75
71
71
62
78
68
87
86
83
73
70
71
76
63
72
71
72
61
Nil
Nil
Nil
protons) of these compounds.
MeO CH2
MeO CH2
MeO
60e62
69e70
95e96
71e73
74e75
55e56
118e119 79
84e86 71
115e117 83
91e93 82
75
58
78
73
72
54
2.2. Bioactivity assessments
O
MeO
MeO NeMe
(OCH2O)
(OCH2O)
(OCH2O)
(OCH2O)
e
e
e
e
CH2
CH2
O
2.2.1. In vitro AChE inhibition
The limited number of commercially available insecticides that
affect a smaller number of enzymes in insects and the resistance to
these agrochemicals patronizes and promotes the study of new
AChE inhibitors systems. AChE inhibitors (AChEIs) as pesticides,
especially against insects and other arthropod vertebrates, are used
in control of disease vectors, e.g. in dengue fever or malaria control.
Insecticidal activity is based on the overstimulation of the cholin-
ergic system in the insect. The original AChEIs used were derived
from compounds developed from organophosphorus war gas
agents that bind irreversibly to AChE. Although the AChE found in
insects are less investigated than mammalian AChE or AChE of the
electric eel Torpedo californica, insect AChEIs are important targets
for some insecticides, which are based on AChE inhibition [29]. In
this work, all the synthesized compounds 1e21 were screened
using Ellman colorimetric method-based AChE inhibition assay
9
NeMe
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
MeO MeO
MeO MeO
MeO MeO
MeO MeO
MeO CH2
MeO CH2
MeO
O
137e139 77
117e118 69
MeO NeMe
H
H
H
H
H
H
H
H
H
H
H
MeO
MeO
MeO
MeO
HO
HO
HO
HO
HO
HO
HO
HO
HO
MeO CH2
MeO CH2
MeO
MeO NeMe
H
H
H
CH2
CH2
O
93e95
88e90
142e143
167e169
133e135
118e119
107e109
151e153
e
e
e
e
NeMe
e
e
e
O
e
e
CH2
O
NeMe
Nil
Nil
Nil
HO
HO
e
e

A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
395
Table 3
biological development of the species A. aegypti in their larval
showing larvicidal activity at concentrations less than 140 ppm,
In vitro AChE inhibitory activity (IC50) of prepared molecules 1e21 and their LogP.
highlighting a-aminonitriles 2 and 7.
Comp. R1
R2
R3
H
X
LogP IC50 (mg/mL) IC50 (mM)
For compound 2, which was obtained amount sufficient to carry
out the assay, were evaluated, under specific conditions, five con-
centrations: 150,130,100, 85 and 55 ppm. The results of insecticidal
activity bioassays in vivo and under laboratory conditions showed
that, in the larval stage, A. aegypti is susceptible to the use of
molecule 2 (resulting in IC50 of 11.6 mg/mL in the AChE inhibition
evaluation) as insecticide.
1
2
3
4
5
6
7
8
H
H
H
H
H
H
H
H
H
HO
MeO
MeO
MeO
CH2
2.09
2.22
1.82
0.94
20.1
11.6
10.3
93.0
45.0
42.0
MeO CH2
MeO CH2
MeO
O
14.1
54.0
MeO
MeO NeMe 1.05
104.4
15.0
11.6
379.0
61.4
51.0
(OCH2O)
(OCH2O)
(OCH2O)
(OCH2O)
e
e
e
e
CH2
CH2
O
0.97
1.87
0.97
14.2
58.0
9
NeMe 1.09
123.2
110.1
88.7
113.7
124.0
117.7
91.5
90.1
91.5
110.3
83.2
101.6
88.9
275.3
381.0
321.0
389.0
406.0
478.0
394.0
363.0
350.1
448.0
358.2
409.2
340.2
1.1
The larval mortality due to the action of the molecule 2 was
observed after 4 h of application of test pots, during which time
morphological changes as thickening, darkening and size reduction
were observed, resulting in the death of the larvae. Larvae that
were not affected during the experiment emerged as normal adults
within the observable parameters within four days. Larvae that
could not reach the water surface when touched were considered
dead. The results of the bioassay mortality and survival were sub-
jected to Probit analysis (Table 5). It should be note that the
organophosphate temephos (Abate) is the most appropriate larvi-
cide to be used in public health programs [36]. Temephos disturbs
the central nervous system through inhibition of cholinesterase
causing death in larvae before reaching the adult stage. Moreover,
the effective dosage recommended by WHO for application of
temephos in domestic containers is only1 ppm and recently it was
reported that lethal concentration, LC50 of A. aegypti were
0.006 ppm under natural conditions [37]. However, it may pollute
the environment and may have adverse effects upon aquatic in-
sects, such as predators that usually have been controlled in the
natural ecological balance. Furthermore in resistant populations of
A. aegyti, the LC50 could be up to 100 times that of susceptible
colonies [38]. Although larvicide activity of comp. 2 was less potent
10
11
12
13
14
15
16
17
18
19
20
21
Gal.a
Diaz.b
MeO MeO
MeO MeO
MeO MeO
MeO MeO
H
H
H
H
H
H
H
H
MeO CH2
MeO CH2
MeO
2.10
1.70
0.83
O
MeO NeMe 0.94
MeO
MeO
MeO
MeO
HO
HO
HO
HO
HO
HO
HO
HO
MeO CH2
MeO CH2
CH2
CH2
O
1.98
1.60
0.71
NeMe 0.83
1.99
1.60
0.71
MeO
O
MeO NeMe 0.83
1.73
3.61
0.30
0.57
1.9
a
Galanthamine, drug used to treat Alzheimer disease.
Diazinon, synthetic insecticide that acts on different soil and foliage pests.
b
to find a relationship between some physico-chemical parameters
of the desired molecules calculated prior to synthesis and enzy-
matic probes (Table 1) and their AChE inhibition activity. Unfortu-
nately, we could state only that the comparison of clogP values and
IC50 values against AChE showed that the clogP would not play a
role in the AChE inhibition since clogP has similar values for active
(comp. 2e4 and 6e8) as well as for inactive (for ex., comp. 5,9)
molecules.
than referent agent, studied comp.
(LC50 < 100 ppm) against A. aegypti larvae [39].
2 is considered active
Additionally, the theoretical toxicity evaluation of tested com-
pounds was performed using the OSIRIS interactive program,
which includes the risk mutagenic, tumorigenic, reproductive and
irritating property evaluation [40]. All the synthesized compounds
1e21 did not present any toxicity risks (Table 6).
Having these results in our hands, we wanted to test potential
in vivo neurotoxic action of the most active inhibitor molecules 2e4
and 6e8 against the A. aegypti larvae.
2.3. In vivo insecticidal activity evaluation
Noteworthy, in the literature there are a few recent studies that
evaluating molecules against any form (larvae, pupae, and adult) of
the A. aegypti mosquitoes [32e35]. Using the biological assays
under laboratory on third-instar larvae of A. aegypti, larvae were
exposed to different concentrations (300, 270, 180, 140, 70, 60, 45
and 25 ppm) of the obtained molecules 2e4 and 6e8 as first
diagnostic test searching higher mortality rates of the larvae. Then,
the molecules with higher mortality were again tested determining
a mortality of the larvae after 24 and 48 h. The bioassay results of
diagnostic tests of compounds 2e7 against A. aegypti larvae in vivo
(Table 4), disclosed that of the all molecules tested affected
3. Conclusion
In summary, we have designed and synthesized a new series of
a-aminonitriles, girgensohnine alkaloid analogs for biochemical
studies that include in silico ADME properties calculations, in vitro
AChE inhibition and in vivo insecticidal activity. Prior to synthetic
and pharmacological studies ADME parameters of this series were
calculated analogs revealing their good pharmacokinetic profiles.
Twenty one new molecules including girgensohnine alkaloid were
tested for enzymatic inhibition as the first filter. It was fond that
obtained
a-aminonitriles 2e4 and 6e8 exhibited moderate to good
Table 4
Diagnostic tests of compounds 2e7 against A. aegypti larvae.
Molecule
Concentration (mg/L, ppm) of comp. and mortality rates of the larvae
48 h. Control
300
270
180
140
70
60
45
25
c
2
6
3
7
4
8
zeroa
nt
nt
nt
nt
ntb
zero
nt
zero
nt
zero
zero
zero
zero
nt
nt
nt
nt
nt
5 þ
5þ
5þ
5þ
5þ
5þ
5þ
zero
zero
zero
zero
zero
zero
5þ
nt
3þ
zero
1þ
5þ
nt
zero
5þ
nt
zero
zero
nt
5þ
5þ
nt
nt
nt
nt
nt
5þ
5þ
a
Zero (0) live larvae.
b
Not evaluated.
c
Number (1-3-5þ) of live larvae.

396
A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
Table 5
Lethal concentration test of comp. 2 against A. aegypti larvae.
Time exposure
Lethal concentrations (LC) causing mortality in 50% (LC50, ppm) and 99% (LC99, ppm)
LC50
CIa
LC99
CI
x2b
Alc
24 h.
48 h.
88.12
87.47
83.43e94.74
82.38e94.82
147.54
155.57
125.30e210.54
128.63e243.93
0.58
7.14
10.39 ꢃ 2.01
9.30 ꢃ 1.96
a
Confidence intervals.
Chi-square.
b
c
Slope ꢃ standard deviation.
AChE inhibition (IC50 ¼ 42e58
m
M) that was enough argument to
of five by using ACD/Lab/Molinspiration/VCCLAB/Osiris online
calculation resources (Tables 1 and 6) [41e44].
test them in in vivo insecticidal activity. Using the biological assays
under laboratory on third-instar larvae of A. aegypti, it was dis-
closed that the molecules 2e4 and 6e8 affected biological devel-
opment of the species A. aegypti in their larval showing larvicidal
4.2. General
activity at concentrations less than 140 ppm, highlighting
a-ami-
IR spectra were recorded on a Lumex Infralum FT-02 spectro-
photometer and the values are expressed as ymax cmꢂ1. 1H and 13
C
nonitriles 2 and 7 (with IC50 ¼ 45 and 51
m
M, respectively) that
makes them possible lead compounds as insecticides. Additionally,
NMR spectra were measured on a Bruker AM-400 spectrometer
(400 MHz 1H NMR and 100 MHz 13C NMR), using CDCl3 or DMSO-
d6 as solvents. TMS was used as an internal standard. Chemical
green reaction conditions, simplicity and efficacy of the proposed
synthetic procedure of the a-aminonitriles allow for their large-
scale preparation. Further investigations on detailed biochemical
mechanism of action are now under way in our laboratories and
their results will be published elsewhere.
shifts (d) and J values are reported in ppm and Hz, respectively. On
DEPT-135 spectra, the signals of CH3, CH2, and CH carbons are
shown as positive (þ) and negative (ꢂ), respectively. Quaternary
carbons are not shown. A Hewlett Packard 5890a Series II Gas
Chromatograph interfaced to an HP 5972 Mass Selective Detector
with an HP MS ChemStation Data system was used for MS identi-
fication at 70 eV using a 60 m capillary column coated with
HP-5 [5% phenylpoly(dimethylsiloxane)]. Melting points were
measured on a Fisher Johns melting point apparatus. Elemental
analyses were performed on a PerkineElmer 2400 Series II analyzer
and were within ꢃ 0.4 of theoretical values. The reaction progress
was monitored using thin layer chromatography on a Silufol UV 254
TLC aluminum sheets. Column chromatography was carried out
using alumina gel (100e200 mesh) and appropriate mixture of
petroleum ether/ethyl acetate for elution. All reagents were pur-
chased from Sigma, SigmaeAldrich and J.T. Baker. The aldehydes
were used as received and the amines were distillated before use.
All anhydrous solvents were dried and purified by standard tech-
niques just before use.
4. Experimental
4.1. Rational design: virtual screenings and molecular properties
calculations
A computational study of all compounds was performed for the
prediction of ADME, toxicological, and physicochemical property
endpoints such as absorption (%ABS), polar surface area (TPSA),
miLog P, number of rotatable bonds, and violations of Lipinski’s rule
Table 6
Osiris calculations of compounds 1e21.
Compd.
Prediction of toxicity risksa
Molecular properties’ calculationsb
Mut
Tumo
Irri
Rep
MW
CLP
LogS
DL
D-S
1
2
3
4
5
6
7
8
ec
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
216
260
246
262
275
244
230
246
259
290
276
292
305
246
232
248
261
246
232
248
261
202
218
231
2.40
2.49
2.17
1.28
1.4
ꢂ2.01
ꢂ2.34
ꢂ2.07
ꢂ1.45
0.95
ꢂ2.74
ꢂ1.48
0.95
0.49
0.54
0.80
0.64
0.94
0.45
0.59
0.51
0.91
0.66
0.88
0.78
0.93
0.50
0.72
0.56
0.94
0.48
0.65
0.53
0.94
0.68
0.54
0.95
4.3. General procedure for the synthesis of
derivatives
a-aminonitrile
ꢂ0.61
4.33
The analogs were synthesized using a modified Strecker reac-
tion as follows: For one-pot reaction of an equimolar mixture of
benzaldehyde (1 mmol) and cyclic amine (1.1 mmol), a round
bottom flask 100 mL capacity was employed and stirred for 30 min.
The source of cyanide was added selecting between KCN and
acetone cyanohydrin (1.5 mmol) and the catalyst SSA (1:1 by
weight) in acetonitrile (15e20 mL) at room temperature (16e24 h).
The progress of the reaction was monitored by TLC (ether:ethyl
acetate, 10:1). Then, the reaction mixture was filtered and evapo-
rated of the solvent, the residue was purified by column chroma-
tography on alumina (100e200 mesh) eluting with petroleum
ether:ethyl acetate (15:1) to furnish title compounds as white
solids with defined melting points (Table 2).
2.8
ꢂ3.02
ꢂ2.75
ꢂ2.13
ꢂ1.63
ꢂ2.36
ꢂ2.09
ꢂ1.47
ꢂ0.97
ꢂ2.03
ꢂ1.76
ꢂ1.14
ꢂ0.64
ꢂ2.03
ꢂ1.76
ꢂ1.14
ꢂ0.64
ꢂ1.74
ꢂ1.12
ꢂ0.62
ꢂ3.28
ꢂ0.82
ꢂ2.34
2.69
2.48
1.59
1.71
2.38
2.07
1.18
1.3
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
ꢂ0.12
2.28
0.69
5.62
2.3
ꢂ2.35
1.98
1.09
1.21
2.3
1.98
1.09
1.21
2.08
1.19
1.31
0.12
ꢂ1.54
3.68
ꢂ2.97
ꢂ0.48
ꢂ2.14
3.11
ꢂ0.25
ꢂ2.02
3.43
4.3.1. 2-(4-Hydroxyphenyl)-2-(piperidin-1-yl)acetonitrile (1)
IR (KBr): 2232 v(C
. d (ppm):
1H NMR (DMSO-d6, 400 MHz)
X
N)
a
Mut e mutagenic; Tumo e tumorigenic; Irri e irritant; Rep e reproductive
9.61 (1H, s, OH), 7.22 (2H, d, J ¼ 8.5 Hz, 2-HAr y 6-HAr), 6.80 (2H, d,
J ¼ 8.6 Hz, 3-HAr and 5-HAr), 5.11 (1H, s, 10-H), 2.40 (4H, m, 2-HPip
and 6-HPip), 1.51 (3-HPip and 5-HPip), 1.39 (2H, m, 4-HPip). 13C NMR
effective.
b
MW e molecular weight; CLP e cLogP: n-octanolewater partition coefficient;
DL e Druglikeness; D-S e Drug-score.
c
No any toxicity risks.
(100 MHz) d (ppm): 157.5 (4-CAr), 128.9 (2-CAr and 6-CAr), 123.6 (1-

A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
397
CAr), 116.2 (CN), 115.2 (3-CAr and 5-CAr), 60.9 (CH), 50.0 (2-CPip and
Calcd for C14H16N2O2: C, 68.83; H, 6.60; N, 11.47; Found: C, 68.66; H,
6.49; N, 11.32.
6-CPip), 25.2 (3-CPip and5-CPip), 23.6 (4-CPip). GCeMS (70 eV):
ꢅ
tR ¼ 18.9 min, m/z ¼ (216, Mþ , 17), 132 (48), 85 (15), 84 (100), 77
(12). Anal. Calcd for C13H16N2O: C, 72.19; H, 7.46; N, 12.95; Found:
72.25; H, 7.54; N, 12.87.
4.3.7. 2-(3,4-Dioxymethylenphenyl)-2-(pyrrolidin-1-yl)acetonitrile
(7)
IR (KBr): 2229 v(C N), 1257 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
(ppm): 6.16e6.08 (3H, m, 2,5,6-HAr), 5.23 (2H, s, 3-
OCH2O), 4.51 (1H, s, 10-H), 1.78e1.71 (2H, m, 2-HPyr), 1.69e1.63
(2H, m, 5-HPyr), 0.92 (4H, m, 3,4-HPyr). 13C NMR (100 MHz)
(ppm):
X
4.3.2. 2-(3,4-Dimethoxyphenyl)-2-(piperidin-1-yl)acetonitrile (2)
400 MHz) d
IR (KBr): 2229 v(C N), 1250 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
400 MHz)
d
(ppm): 6.21e6.12 (3H, m, 2,5,6-HAr), 4.38 (1H, s, 10-H),
d
2.95 (6H, s, 3,4-OCH3), 1.72e1.54 (4H, m, 2,6-HPip), 0.79e0.64 (4H,
148.6 (3-CAr), 148.4 (4-CAr), 129.3 (1-CAr), 121.8 (6-CAr), 117.6 (eCN),
m, 3,5-HPip), 0.59 (2H, d, J ¼ 5.2 Hz, 4-HPip). 13C NMR (100 MHz)
109.0 (2-CAr), 108.8 (5-CAr), 102.3 (3-OCH2O), 58.5 (10-C), 50.6 (2,5-
d
(ppm): 149.9 (4-CAr), 149.0 (3-CAr), 126.8 (1-CAr), 120. 8 (6-CAr),
C
Pyr), 23.8 (3,4-CPyr). GCeMS (70 eV): tR ¼ 18.3 min, m/z ¼ (230,
ꢅ
117.1 (eCN),112.4 (2-CAr),112.0 (5-CAr), 62.1 (10-C), 56. 4 (3,4-OCH3),
51.1 (2,6-CPip), 26.2 (3,5-CPip), 24.6 (4-CPip). GCeMS (70 eV):
Mþ , 10), 161 (23), 160 (100), 70 (20). Anal. Calcd for C13H14N2O2: C,
67.81; H, 6.13; N, 12.17. Found: C, 67.96; H, 6.32; N, 12.31.
ꢅ
tR ¼ 20.7 min, m/z ¼ (260, Mþ , 6), 177 (30), 176 (100), 131 (5), 84
(59). Anal. Calcd for C15H20N2O2: C, 69.20; H, 7.74; N, 10.76; Found:
C, 69.05; H, 7.89; N, 10.54.
4.3.8. 2-(3,4-Dioxymethylenphenyl)-2-(morpholin-1-yl)acetonitrile
(8)
IR (KBr): 1250v(N-C), 1119 v(C-O-C) cmꢂ1 1H NMR (DMSO-d6,
.
4.3.3. 2-(3,4-Dimethoxyphenyl)-2-(pyrrolidin-1-yl)acetonitrile (3)
400 MHz) d (ppm): 6.18e6.09 (3H, m, 2,5,6-HAr), 5.24 (2H, s, 3-
IR (KBr): 2229 v(C N), 1273 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
OCH2O), 4.43 (1H, s, 10-H), 2.83e2.72 (4H, m, 3,5-HMorph), 1.74e
X
400 MHz)
3.06 (6H, s, 3,4-OCH3), 1.88e1.77 (4H, m, 2,5-HPyr), 1.04e1.01 (4H,
m, 3,4-HPyr). 13C NMR (100 MHz)
(ppm): 150.2 (4-CAr), 150.1 (3-
d
(ppm): 6.28e6.26 (3H, m, 2,5,6-HAr), 4.62 (1H, s, 10-H),
1.64 (2H, m, 6-HMorph), 1.61e1.53 (2H, m, 2-HMorph). 13C NMR
(100 MHz) d (ppm): 148.7 (3-CAr), 148.6 (4-CAr), 127.5 (1-CAr), 122.3
d
(6-CAr), 116.8 (eCN), 109.0 (2-CAr), 109.0 (5-CAr), 102.4 (3-OCH2O),
C
Ar), 128.1 (1-CAr), 120.8 (6-CAr), 118.0 (eCN), 112.8 (2-CAr), 112.4
66.8 (10-C), 61.5 (3,5-CMorph), 50.4 (2,6-CMorph). GCeMS (70 eV):
ꢅ
(5-CAr), 58.9 (10-C), 56.8 (3,4-OCH3), 50.9 (2,5-CPyr), 24.1 (3,4-CPyr).
tR ¼ 20.3 min, m/z ¼ (246, Mþ , 12), 161 (21), 160 (100), 102 (14), 86
ꢅ
GCeMS (70 eV): tR ¼ 19.4 min, m/z ¼ 246 (Mþ ), 177 (29), 176 (100),
(69), 56 (64). Anal. Calcd for C13H14N2O3: C, 63.40; H, 5.73; N, 11.38;
Found: C, 63.22; H, 5.85; N, 11.27.
151 (6), 146 (6), 70 (34). Anal. Calcd for C14H18N2O2: C, 68.27; H,
7.37; N, 11.37; Found: C, 68.36; H, 7.55; N, 11.16.
4.3.9. 2-(3,4-Dioxymethylenphenyl)-2-(4-methylpiperazin-1-yl)
4.3.4. 2-(3,4-Dimethoxyphenyl)-2-(morpholin-1-yl)acetonitrile (4)
acetonitrile (9)
IR (KBr): 2229 v(C N), 1281 v(N-C), 1111 v(C-O-C) cmꢂ1
.
1H NMR
IR (KBr): 2227 v(C N),1247 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
X
(DMSO-d6, 400 MHz)
d
(ppm): 6,23e6.13 (3H, m, 2,5,6-HAr), 4.43
400 MHz)
d
(ppm): 7.00 (1H, ddd, J ¼ 8.0, 1.8, 0.9 Hz, 6-HAr), 6.97
(1H, s, 10-H), 2.95 (6H, s, 3,4-OCH3), 2.79 (4H, sa, 3,5-HMorph), 1.68
(1H, dd, J ¼ 1.3, 0.5 Hz, 2-HAr), 6.79 (1H, d, J ¼ 8.0 Hz, 5-HAr), 5.98
(2H, m, 6-HMorph), 1.63e1.52 (2H, m, 2-HMorph). 13C NMR (100 MHz)
(2H, s, 3-OCH3O), 4.73 (1H, s, 10-H), 2.72e2.19 (11H, m, 2-6-HPip, Ne
d
(ppm): 150.1 (4-CAr), 149.8 (3-CAr), 125.9 (1-CAr), 121.1 (6-CAr),
CH3). 13C NMR (100 MHz)
d (ppm): 148.5 (3-CAr), 148.4 (4-CAr), 127.1
117.0 (eCN), 112.4 (2-CAr), 112.2 (5-CAr), 66.9 (10-C), 61.6 (3,5-
(1-CAr), 121.8 (þ, 6-CAr), 115.7 (eCN), 108.5 (þ, 2-CAr), 108.4 (þ, 5-
C
Morph), 56.5 (3,4-OCH3), 50.4 (2,6-CMorph). GCeMS (70 eV):
C
Ar), 101.8 (þ, 3-OCH2O), 61.9 (þ, 10-C), 55.1 (ꢂ, 2-6-CN-pip), 46.2
ꢅ
ꢅ
tR ¼ 21.0 min, m/z ¼ (262, Mþ , 7), 177 (23), 176 (100), 86 (38), 56
(29). Anal. Calcd for C14H18N2O3: C, 64.10; H, 6.92; N, 10.68; Found:
C, 64.28; H, 6.87; N, 10.59.
(þ, NeCH3). GCeMS (70 eV): tR ¼ 20.2 min, m/z ¼ (259, Mþ , 31),
160 (19), 99 (100), 70 (14), 56 (35). Anal. Calcd for C14H17N3O2: C,
64.85; H, 6.61; N, 16.20; Found: C, 64.62; H, 6.39; N, 16.43.
4.3.5. 2-(3,4-Dimethoxyphenyl)-2-(4-methylpiperazin-1-yl)
4.3.10. 2-(3,4,5-Trimethoxyphenyl)-2-(piperidin-1-yl) acetonitrile
acetonitrile (5)
(10)
IR (KBr): 2220 v(C N), 1247 v(N-C), cmꢂ1
.
1H NMR (DMSO-d6,
IR (KBr): 2221v(C N),1231 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
X
X
400 MHz)
d
(ppm): 7.06 (1H, ddd, J ¼ 8.3, 2.1, 0.7 Hz, 6-HAr), 6.98
400 MHz) d
(ppm): 6.76 (2H, s, 2,6-HAr), 4.75 (1H, s, 10-H), 3.87 (6H,
(1H, d, J ¼ 2.0 Hz, 2-HAr), 6.83 (1H, d, J ¼ 8.3 Hz, 5-HAr), 4.76 (1H, s,
s, 3,5-OCH3), 3.84 (3H, s, 4-OCH3), 2.59e1.68 (4H, m, 2,6-HPip),
10-H), 3.87 (6H, s, 3,4-OCH3), 2.74e2.16 (11H, m, 2-6-HNpip, -NCH3).
1.68e1.53 (4H, m, 3-5-HPip), 1.48 (2H, dd, J ¼ 10.8, 5.2 Hz 4-HPip). 13
C
13C NMR (100 MHz)
d
(ppm): 149.6 (3-CAr), 149.4 (4-CAr), 125.6 (1-
NMR (100 MHz) d (ppm): 153.6 (3,5-CAr), 138.2 (4-CAr), 129.4 (1-
C
Ar), 120.6 (þ, 6-CAr), 115.8 (eCN), 111.0 (þ, 5-CAr), 110.9 (þ, 2-CAr),
C
Ar), 116.0 (eCN), 104.8 (þ, 2,6-CAr), 63.3 (þ, 10-C), 61.2 (þ, 4-
62.0 (þ, 10-C), 56.2 (þ, 3-OCH3), 56.2 (þ, 4-OCH3), 55.1 (ꢂ, 2-6-
CN-pip), 46.2 (þ, eNCH3). GCeMS (70 eV): tR ¼ 21.0 min, m/
OCH3), 56.5 (þ, 3,5-OCH3), 51.2 (ꢂ, 2,6-CPip), 26.1 (ꢂ, 3,5-CPip),
ꢅ
24.2 (ꢂ, 4-CPip). GCeMS (70 eV): tR ¼ 21.2 min, m/z ¼ (290, Mþ ),
ꢅ
z ¼ (275, Mþ , 28), 176 (10), 99 (100), 70 (14), 56 (34). Anal. Calcd for
207 (63), 206 (100), 192 (12), 176 (32), 84 (50). Anal. Calcd for
C
15H21N3O2: C, 65.43; H, 7.69; N, 15.26; Found: C, 65.57; H, 7.81; N,
C16H22N2O3: C, 66.18; H, 7.64; N, 9.65; Found: C, 66.25; H, 7.86; N,
15.08.
9.47.
4.3.6. 2-(3,4-Dioxymethylenphenyl)-2-(piperidin-1-yl)acetonitrile
4.3.11. 2-(3,4,5-Trimethoxyphenyl)-2-(pyrrolidin-1-yl) acetonitrile
(6)
(11)
IR (KBr): 2229 v(C N), 1257 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
IR (KBr): 2220v(C N),1235 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
(ppm): 6.73 (2H, s, 2,6-HAr), 4.97 (1H, s, 10-H), 3.87 (6H,
s, 3,5-OCH3), 3.84 (3H, s, 4-OCH3), 2.71e2.59 (4H, m, 2,5-HPir),1.89e
1.78 (4H, m, 3,4-HPir). 13C NMR (100 MHz)
(ppm): 153.7 (3,5-CAr),
X
X
400 MHz)
d
(ppm): 6.16e6.08 (3H, m, 2,5,6-HAr), 5.24 (2H, s, 3-
400 MHz) d
OCH2O), 4.36 (1H, s, 10-H), 1.70e1.52 (4H, m, 2,6-HPip), 0.77e0.62
(4H, m, 3,5-HPip), 0.58 (2H, d, J ¼ 5.1 Hz, 4-HPip). 13C NMR (100 MHz)
d
d
(ppm): 148.6 (3-CAr), 148.4 (4-CAr), 128.4 (1-CAr), 121.9 (6-CAr),
138.3 (4-CAr), 130.1 (1-CAr), 116.5 (eCN), 104.8 (þ, 2,6-CAr), 61.2 (þ,
117.0 (eCN), 108.9 (2-CAr), 108.8 (5-CAr), 102.4 (3-OCH2O), 62.0 (10-
C), 51.1 (2,6-CPip), 26.2 (30,50-CPip), 24.6 (40-CPip). GCeMS (70 eV):
10-C), 59.8 (þ, 4-OCH3), 56.5 (þ, 3,5-OCH3), 50.6 (ꢂ, 2,5-CPyr), 23.8
ꢅ
(ꢂ, 3,4-CPyr). GCeMS (70 eV): tR ¼ 20.0 min, m/z ¼ (276, Mþ ), 207
ꢅ
tR ¼ 20.0 min, m/z ¼ (244, Mþ ,10),161 (24),160 (100), 84 (85). Anal.
(68), 206 (100), 192 (15), 176 (39), 70 (21). Anal. Calcd for

398
A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
ꢅ
C15H20N2O3: C, 65.20; H, 7.30; N, 10.14; Found: C, 65.42; H, 7.51; N,
10.27.
z ¼ (248, Mþ , 16), 162 (100) 163 (23), 86 (57), 56 (37). Anal. Calcd
for C13H16N2O3: C, 62.89; H, 6.50; N, 11.28; Found: C, 62.74; H, 6.78;
N, 11.11.
4.3.12. 2-(3,4,5-Trimethoxyphenyl)-2-(morpholin-1-yl)acetonitrile
(12)
4.3.17. 2-(3-Hydroxy-4-methoxyphenyl)-2-(4-methylpiperazin-1-
IR (KBr): 2224v(C N),1248 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
(ppm): 6.74 (2H, s, 2,6-HAr), 4.74 (1H, s, 10-H), 3.87 (6H,
s, 3,5-OCH3), 3.83 (3H, s, 4-OCH3), 3.79e3.66 (4H, m, 3,5-HMorf),
2.68e2.43 (4H, m, 2,6-HMorf). 13C NMR (100 MHz)
(ppm): 153.7
yl)acetonitrile (17)
X
400 MHz)
d
IR (KBr): 2232v(C N),1236 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
400 MHz)
d
(ppm): 7.03 (1H, dd, J ¼ 2.2, 2-HAr), 6.98 (1H, ddd,
d
J ¼ 8.3, 2.2, 0.7 Hz, 6-HAr), 6.82 (1H, d, J ¼ 8.3 Hz, 5-HAr), 4.72 (1H, s,
(3,5-CAr), 138.5 (4-CAr), 128.2 (1-CAr), 115.5 (eCN), 105.1 (þ, 2,6-CAr),
66.9 (ꢂ, 3,5-CMorf), 62.8 (þ, 10-C), 61.2 (þ, 4-OCH3), 56.5 (þ, 3-5-
OCH3), 50.3 (ꢂ, 2,6-CMorf). GCeMS (70 eV): tR ¼ 21.3 min, m/
10-H), 3.88 (3H, s, 4-OCH3), 2.74e2.30 (8H, m, 2-6-HPip), 2.28 (3H, s,
NeCH3). 13C NMR (100 MHz)
d (ppm): 147.6 (4-CAr), 146.4 (3-CAr),
126.2 (1-CAr), 119.8 (þ, 6-CAr), 115.8 (eCN),114.7 (þ, 5-CAr), 110.7 (þ,
ꢅ
z ¼ (292, Mþ ), 207 (52), 206 (100), 176 (14), 86 (20), 66 (14). Anal.
2-CAr), 61.7 (þ, 10-C), 56.3 (þ, 4-OCH3), 55.0 (ꢂ, 2,6-CN-pip), 46.1 (þ,
ꢅ
Calcd for C15H20N2O4: C, 61.63; H, 6.90; N, 9.58; Found: C, 61.47; H,
6.63; N, 9.45.
-NCH3). GCeMS (70 eV): tR ¼ 22.6 min, m/z ¼ (261, Mþ ), 236 (67),
165 (47), 137 (100), 99 (62), 56 (47). Anal. Calcd for C14H19N3O2: C,
64.35; H, 7.33; N, 16.08; Found: C, 64.57; H, 7.46; N, 16.17.
4.3.13. 2-(3,4,5-Trimethoxyphenyl)-2-(4-methylpiperazin-1-yl)
acetonitrile (13)
4.3.18. 2-(4-Hydroxy-3-methoxyphenyl)-2-(piperidin-1-yl)
IR (KBr): 2221v(C N),1247 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
acetonitrile (18)
X
400 MHz)
d
(ppm): 6.73 (2H, d, J ¼ 0.5 Hz, 2,6-HAr), 4.76 (1H, s, 10-
IR (KBr): 2230v(C N),1248 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
H), 3.86 (6H, s, 3,5-OCH3), 3.83 (3H, s, 4-OCH3), 2.78e2.14 (11H, m,
400 MHz)
d
(ppm): 7.04 (1H, ddd, J ¼ 8.2, 2.1, 0.8 Hz, 6-HAr), 7.00
2-6-HPip, NeCH3). 13C NMR (100 MHz)
d
(ppm): 153.7 (3,5-CAr),
(1H, d, J ¼ 2.0 Hz, 2-HAr), 6.91 (1H, d, J ¼ 8.2 Hz, 5-HAr), 4.75 (1H, s,
138.4 (4-CAr), 128.8 (1-CAr), 115.6 (eCN), 104.9 (þ, 2,6-CAr), 62.4 (þ,
10-H), 3.91 (3H, s, 3-OCH3), 2.58e2.41 (4H, m, 2,6-HPip), 1.68e1.45
10-C), 61.2 (þ, 4-OCH3), 56.5 (þ, 3,5-OCH3), 55.1 (ꢂ, 2-6-CN-pip), 46.2
(6H, m, 3-5-HPip). 13C NMR (100 MHz)
d (ppm): 146.9 (3-CAr), 146.2
ꢅ
(þ, NeCH3). GCeMS (70 eV): tR ¼ 22.1 min, m/z ¼ (305, Mþ ), 305
(4-CAr), 125.6 (1-CAr), 121.2 (þ, 6-CAr), 116.2 (eCN), 114.6 (þ, 5-CAr),
110.4 (þ, 2-CAr), 63.0 (þ, 10-C), 56.4 (þ, 3-OCH3), 51.3 (þ, 2,6-Cpip),
26.1 (ꢂ, 3,5-Cpip), 24.3 (ꢂ, 4-Cpip). GCeMS (70 eV): tR ¼ 23.6 min, m/
(26), 206 (16), 99 (100), 70 (14), 56 (31). Anal. Calcd for C16H23N3O3:
C, 62.93; H, 7.59; N, 13.76; Found: C, 62.80; H, 7.82; N, 13.49.
ꢅ
z ¼ (246, Mþ , 19), 162 (80), 163 (19), 85 (19), 84 (100). Anal. Calcd
4.3.14. 2-(3-Hydroxy-4-methoxyphenyl)-2-(piperidin-1-yl)
for C14H18N2O2: C, 68.27; H, 7.37; N, 11.37; Found: C, 68.11; H, 7.23;
N, 11.45.
acetonitrile (14)
IR (KBr): 2232v(C N),1248 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
400 MHz)
d
(ppm): 7.09 (1H, dd, J ¼ 2.2, 0.6 Hz, 2-HAr), 7.02 (1H,
4.3.19. 2-(4-Hydroxy-3-methoxyphenyl)-2-(pyrrolidin-1-yl)
ddd, J ¼ 8.3, 2.2, 0.8 Hz, 6-HAr), 6.83 (1H, d, J ¼ 8.3 Hz, 5 HAr), 4.72
acetonitrile (19)
(1H, s,10-H), 3.89 (3H, s, 4-OCH3), 2.58e2.34 (4H, m, 2,6-HPip),1.66e
IR (KBr): 2217v(C N),1232 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
1.51 (4H, m, 3,5-HPip), 1.51e1.41 (2H, dd, J ¼ 10.8, 5.2 Hz 4-HPip). 13
C
400 MHz)
d
(ppm): 7.01 (1H, dd, J ¼ 8.2, 2.0 Hz, 6-HAr), 6.98 (1H, d,
NMR (100 MHz)
d
(ppm): 147.1 (4-CAr), 146.1 (3-CAr), 126.9 (1-CAr),
J ¼ 1.8 Hz, 2-HAr), 6.89 (1H, d, J ¼ 8.1 Hz, 5-HAr), 4.95 (1H, s, 10-H),
119.8 (þ, 6-H), 116.1 (eCN),114.4 (þ, 5-CAr), 110.5 (þ, 2-CAr), 62.8 (þ,
3.88 (3H, s, 3-OCH3), 2.70e2.58 (4H, m, 2,5-HPyr), 1.89e1.76 (4H, m,
10-C), 56.3 (þ, 4-OCH3), 51.1 (ꢂ, 2,6-CPip), 26.1 (ꢂ, 3,5-CPip), 24.3 (ꢂ,
3,4-HPyr). 13C NMR (100 MHz)
d (ppm): 147.0 (3-CAr), 146.3 (4-CAr),
ꢅ
4-CPip). GCeMS (70 eV): tR ¼ 21.5 min, m/z ¼ (246, Mþ ), 221 (24),
126.3 (1-CAr), 121.0 (þ, 6-CAr), 117.0 (eCN), 114.7 (þ, 5-CAr), 110.3 (þ,
137 (100), 98 (20), 84 (77). Anal. Calcd for C14H18N2O2: C, 68.27; H,
7.37; N, 11.37; Found: C, 68.45; H, 7.59; N, 11.52.
2-CAr), 59.4 (þ, 10-C), 56.3 (þ, 3-OCH3), 50.6 (ꢂ, 2,5-CPyr), 23.7 (ꢂ,
ꢅ
3,4-CPyr). GCeMS (70 eV): tR ¼ 20.1 min, m/z ¼ (232, Mþ ), 207 (38),
206 (33), 138 (48), 137 (100), 70 (73). Anal. Calcd for C13H16N2O2: C,
67.22; H, 6.94; N, 12.06; Found: C, 67.45; H, 6.83; N, 12.27.
4.3.15. 2-(3-Hydroxy-4-methoxyphenyl)-2-(pyrrolidin-1-yl)
acetonitrile (15)
IR (KBr): 2220 v(C N),1218 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
4.3.20. 2-(4-Hydroxy-3-methoxyphenyl)-2-morpholinoacetonitrile
X
400 MHz)
d
(ppm): 7.06 (1H, d, J ¼ 2.2 Hz, 2-HAr), 7.00 (1H, ddd,
(20)
J ¼ 8.3, 2.2, 0.7 Hz, 6-HAr), 6.82 (1H, d, J ¼ 8.3 Hz, 5-HAr), 4.94 (1H, s,
IR (KBr): 2236v(C
cmꢂ1 1H NMR (DMSO-d6, 400 MHz)
.
N)
X
10-H), 3.88 (3H, s, 4-OCH3), 2.69e2.57 (4H, m, 2,5-Hpir), 1.85e1.77
d
(ppm): 7.02 (1H, ddd, J ¼ 8.2, 2.1, 0.7 Hz, 6-HAr), 6.98 (1H, d,
(4H, m, 3,4-Hpir). 13C NMR (100 MHz)
d
(ppm): 147.2 (4-CAr), 146.1
J ¼ 2.0 Hz, 2-HAr), 6.90 (1H, d, J ¼ 8.2 Hz, 5-HAr), 4.73 (1H, s, 10-H),
(3-CAr), 127.6 (1-CAr), 119.5 (þ, 6-H), 116. 6 (eCN), 114.3 (þ, 5-CAr),
3.90 (3H, s, 3-OCH3), 3.79e3.64 (4H, m, 3,5-HMorf), 2.63e2.49 (4H,
110. 7 (þ, 2-CAr), 59.0 (þ, 10-C), 56.3 (þ, 4-OCH3), 50.5 (ꢂ, 2,5-Cpir),
m, 2,6-HMorf). 13C NMR (100 MHz)
d (ppm): 147.1 (3-CAr), 146.5 (4-
ꢅ
23.6 (ꢂ, 3,4-Cpir). GCeMS (70 eV): tR ¼ 20.7 min, m/z ¼ (232, Mþ ),
C
Ar), 124.4 (1-CAr), 121.5 (þ, 6-CAr), 115.7 (eCN), 114.8 (þ, 5-CAr),
207 (20), 137 (100), 84 (22), 70 (50). Anal. Calcd for C13H16N2O2: C,
67.22; H, 6.94; N, 12.06; Found: C, 67.01; H, 7.02; N, 11.91.
110.6 (þ, 2-CAr), 66.9 (ꢂ, 3,5-CMorf), 62.4 (þ, 10-C), 56.3 (þ, 3-OCH3),
ꢅ
50.2 (ꢂ, 2,6-CMorf). GCeMS (70 eV): tR ¼ 23.9 min, m/z ¼ (248, Mþ
,
29), 162 (100), 87 (24), 86 (55), 56 (39). Anal. Calcd for C13H16N2O3:
C, 62.89; H, 6.50; N, 11.28; Found: C, 62.67; H, 6.78; N, 11.45.
4.3.16. 2-(3-Hydroxy-4-methoxyphenyl)- 2-(morpholin-1-yl)
acetonitrile (16)
IR (KBr): 2238v(C N),1249 v(N-C) cmꢂ1
.
1H NMR (DMSO-d6,
4.3.21. 2-(4-Hydroxy-3-methoxyphenyl)-2-(4-methylpiperazin-1-
X
400 MHz)
d
(ppm): 7.07 (1H, d, J ¼ 2.2, 2-HAr), 7.01 (1H, ddd, J ¼ 8.3,
yl)acetonitrile (21)
2.2, 0.7 Hz, 6-HAr), 6.84 (1H, d, J ¼ 8.3 Hz, 5-HAr), 5.90 (1H, sa, 3-OH),
IR (KBr): 2247v(C N),1219 v(N-C) cmꢂ1 1H NMR (DMSO-d6,
.
X
4.72 (1H, s,10-H), 3.89 (3H, s, 4-OCH3), 3.78e3.62 (4H, m, 3,5-HMorf),
400 MHz)
d
(ppm): 6.02 (1H, d, J ¼ 1.7 Hz, 2-HAr), 5.95 (1H, dd,
2.66e2.45 (4H, m, 2,6-HMorf). 13C NMR (100 MHz)
d
(ppm): 147.4 (4-
J ¼ 8.2, 1.7 Hz, 6-HAr), 5.91 (1H, d, J ¼ 8.1 Hz, 5-HAr), 4.28 (1H, s, 10-
C
Ar), 146.2 (3-CAr), 125.7 (1-CAr), 120.0 (þ, 6-H), 115.7 (eCN), 114.5
H), 2.87 (3H, s, 3-OCH3), 1.73e1.21 (11H, m, 2-6-HPip, NeCH3). 13
C
(þ, 5-CAr), 110.6 (þ, 2-CAr), 67.0 (ꢂ, 3,5-CMorph), 62.2 (þ, 10-C), 56.3
(þ, 4-OCH3), 50.1 (ꢂ, 2,6-CMorph). GCeMS (70 eV): tR ¼ 21.9 min, m/
NMR (100 MHz) d (ppm): 148.7 (3-C), 148.0 (4-C), 124.9 (1-C), 121.3
(þ, 6-H), 117.3 (eCN), 116.3 (þ, 5-C), 112.6 (þ, 2-C), 61.4 (þ, 10-C),

A.L. Carreño Otero et al. / European Journal of Medicinal Chemistry 78 (2014) 392e400
399
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ꢅ
(70 eV): tR ¼ 24.6 min, m/z ¼ (261, Mþ ,37), 162 (46), 99 (20), 56
(36), 44 (21), 42 (16). Anal. Calcd for C14H19N3O2: C, 64.35; H, 7.33;
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The authors acknowledge the financing from the Autonomous
Equity National Financing Fund for Science, Technology and Inno-
vation, Francisco Jose de Caldas, RC-contract 0572-2012, and the
“Vicerrectoria de investigación y extensión” from Universidad In-
dustrial de Santander for supporting the project code 5680. A.L.C.O.
acknowledges the financial supporting from doctoral program
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