Synthesis and biological evaluation of N-aryl-7-methoxybenzo[b]furo[3,2-d] pyrimidin-4-amines and their N-arylbenzo[b]thieno[3,2-d]pyrimidin-4-amine analogues as dual inhibitors of CLK1 and DYRK1A kinases

Article abstract of DOI:10.1016/j.ejmech.2012.11.030

Novel N-aryl-7-methoxybenzo[b]furo[3,2-d]pyrimidin-4-amines (1) and their N-arylbenzo[b]thieno[3,2-d]pyrimidin-4-amine analogues (2) were designed and prepared for the first time via microwave-accelerated multi-step synthesis. Various anilines were conden

Full text of DOI:10.1016/j.ejmech.2012.11.030

European Journal of Medicinal Chemistry 59 (2013) 283e295
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and biological evaluation of N-aryl-7-methoxybenzo[b]furo[3,2-d]
pyrimidin-4-amines and their N-arylbenzo[b]thieno[3,2-d]pyrimidin-4-amine
analogues as dual inhibitors of CLK1 and DYRK1A kinases
Yvonnick Loidreau a, Pascal Marchand b, Carole Dubouilh-Benard a, Marie-Renée Nourrisson b,
,
,
*
Muriel Duflos b, Nadège Loaëc c d, Laurent Meijer d, Thierry Besson a
a Université de Rouen, Laboratoire de Chimie Organique et Bio-organique, Réactivité et Analyse (C.O.B.R.A.), CNRS UMR 6014 & FR3038, Institut de Recherche en Chimie Organique
Fine (I.R.C.O.F.) rue Tesnière, 76130 Mont Saint-Aignan, France
b Université de Nantes, Nantes Atlantique Universités, Laboratoire de Chimie Thérapeutique, Cibles et Médicaments des Infections et du Cancer, IICiMed UPRES EA 1155,
UFR des Sciences Pharmaceutiques et Biologiques, 1 rue Gaston Veil, 44035 Nantes, France
c Protein Phosphorylation & Human Disease Group, Station Biologique, 29680 Roscoff, France
d Manros Therapeutics, Centre de Perharidy, 29680 Roscoff, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Novel N-aryl-7-methoxybenzo[b]furo[3,2-d]pyrimidin-4-amines (1) and their N-arylbenzo[b]thieno[3,2-
d]pyrimidin-4-amine analogues (2) were designed and prepared for the first time via microwave-
accelerated multi-step synthesis. Various anilines were condensed with N0-(2-cyanaryl)-N,N-dime-
thylformimidamide intermediates obtained by reaction of 3-amino-6-methoxybenzofuran-2-carbonitrile
(3) and 3-amino-6-methoxybenzothiophene-2-carbonitrile (4) precursors with dimethylformamide
dimethylacetal. The inhibitory potency of the final products against five protein kinases (CDK5/p25,
Received 18 October 2012
Received in revised form
12 November 2012
Accepted 19 November 2012
Available online 24 November 2012
CK1d/ε, GSK3a/b, DYRK1A and CLK1) was estimated. Compounds (2aez) turned out to be particularly
promising for the development of new pharmacological dual inhibitors of CLK1 and DYRK1A kinases.
Keywords:
Microwave-assisted chemistry
Benzo[b]furo[3,2-d]pyrimidin-4-amines
Benzo[b]thieno[3,2-d]pyrimidin-4-amines
Alzheimer’s disease
Ó 2012 Elsevier Masson SAS. All rights reserved.
DYRK
CLK
Kinase inhibitors
1. Introduction
Our research groups are mainly invested in the synthesis of
C,N,S- or C,N,O-containing heterocyclic precursors of bioactive
Harmine [1] is a
b
-carboline alkaloid identified as potent
molecules able to modulate the activity of kinases in signal trans-
duction [4,5]. Inspired by the 6,5,6-fused tricyclic skeleton of har-
mine molecule, we envisioned to prepare various N-aryl-7-
methoxybenzo[b]furo[3,2-d]pyrimidin-4-amines (1) and their
N-arylbenzo[b]thieno [3,2-d]pyrimidine analogues (2), themselves
substituted in position 4 of the pyrimidine ring by an aromatic
amine (Scheme 1). A literature survey revealed that the synthesis
and biological evaluation of such derivatives had not been previ-
ously described.
This paper describes the development of a simple and reliable
method that allows the preparation of a library of new benzofuro-
and benzothieno[3,2-d]pyrimidines for which interesting kinase
inhibitory activities were observed. The main part of the chemistry
described in this paper was realized under microwave irradiation in
a combinatorial chemistry approach. The evaluation of kinase inhi-
bition of the products obtained was performed on Ser/Thr kinases
inhibitor of dual-specificity tyrosine phosphorylation-regulated
kinase 1A (DYRK1A, IC50 ¼ 80 nM in vitro), a kinase implicated in
Down Syndrome (DS) and Alzheimer’s disease (AD) [2]. Other
members of the DYRK family are also inhibited to a lesser extent
(DYRK2 IC50 ¼ 900 nM and DYRK3 IC50 ¼ 800 nM). These eukary-
otic kinases belong to a larger family known as the CMGC group of
proline/arginine directed serine/threonine kinases. Cyclin-
dependent kinases (CDKs), glycogen synthase kinases (GSKs), and
CDC2-like kinases (CLKs) are also members of the CMGC group.
These enzymes are involved in many major diseases, including
cancer and neurodegenerative disorders [3].
* Corresponding author. Tel.: þ33 (0)235522904; fax: þ33(0)235522962.
E-mail address: thierry.besson@univ-rouen.fr (T. Besson).
0223-5234/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2012.11.030

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Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
Scheme 1. Structural analogy between harmine and the target compounds 1 and 2.
(CDK5, GSK3, DYRK1A, CLK1 and CK1) chosen for their strong
implication in various regulation processes, especially AD [3].
cyanomethylthioether intermediate (not isolated) gave the expected
product 4 in moderate yield (55%) (Scheme 4) [11].
2.2. Synthesis of N,N-dimethylformimidamides (5 and 6)
2. Chemistry
With starting enaminonitriles 3 and 4 now available, the second
step in the synthesis consisted in formation of N,N-dime-
thylformimidamide intermediates 5 and 6. It was realized by the
reaction of 3 and 4 with N,N-dimethylformamide dimethylacetal
(DMF-DMA). After various attempts to optimize the reaction
parameters (time, temperature and applied microwave power), the
expected products 5 and 6 were obtained with excellent yields
(99%) after 30 min irradiation at 90 ꢀC. Note that microwave heating
was realized at atmospheric pressure in a controlled multimode
cavity and not in pressurized vials as often described in various
processes [12]. Open vessel microwave experiments have some
advantages, such as the possibility of easier scale-up and of using
standard laboratory glassware. Irradiation wattage at 800 W was
enough to efficiently reach the programmed temperature. This
The target molecules we studied were 7-methoxylbenzo[b]furo
[3,2-d]pyrimidines (1) and their benzo[b]thieno[3,2-d]pyrimidines
analogues (2) substituted in position 4 of the pyrimidine ring by
a primary or an aromatic amine. The retrosynthetic pathway
depicted in Scheme 2 started from 3-amino-6-methoxybenzofuran-
2-carbonitrile (3) and 3-amino-6-methoxybenzothiophene-2-
carbonitrile (4) which could be transformed into their correspond-
ing N,N-dimethylformamidine derivatives 5 and 6. The next step
consisted in nucleophilic attack of the intermediate amidines by
ammonia or aromatic amines to give the expected tricyclic
compounds 1e2 via a thermal-sensitive Dimroth rearrangement.
This fast and convenient procedure was recently explored for
a general access to pyrimidine-condensed heterocyclic compounds
which can be useful for the design of novel bioactive compounds [6].
parameter was mainly monitored via
a contactless-infrared
pyrometer which was calibrated in control experiments with
a fibre-optic contact thermometer.
2.1. Synthesis of the starting 3-amino-6-methoxybenzofuran-2-
carbonitrile (3) and 3-amino-6-methoxybenzo[b]thiophene-2-
carbonitrile (4)
2.3. Synthesis of N-aryl-7-methoxybenzo[b]furo[3,2-d]pyrimidin-
4-amines (1 series) and N-aryl-7-methoxybenzo[b]thieno[3,2-d]
pyrimidin-4-amine derivatives (2 series)
The 6-methoxybenzofurane derivative (3) was obtained in two
steps using a methodology previously described for the synthesis
of 3-aminofuro[3,2-b]pyridine-2-carbonitriles [7]. Subsequently,
2,4-dimethoxybenzonitrile was treated with 1-decanethiol
at 110 ꢀC in dimethylformamide to give the 2-hydroxy-4-
methoxybenzonitrile intermediate (7) in a very good yield of 96%
[8]. O-Alkylation of phenol derivative (7) and ring closure of the
corresponding cyanomethylether intermediate (not isolated) were
performed in the presence of potassium carbonate (K2CO3) as base.
The target product (3) was obtained in good yield (79%) (Scheme 3).
Synthesis of 3-amino-6-methoxybenzo[b]thiophene-2-carbonitrile
(4) started by treatment of commercially available 4-bromo-3-
nitroanisole with copper (I) cyanide (CuCN) in anhydrous dime-
thylformamide (DMF) [9]. Treatment of the resulting 4-methoxy-2-
nitrobenzonitrile (8) with 3-mercaptopropionitrile [10] in the pres-
ence of aqueous potassium hydroxide in DMF at 0 ꢀC was followed by
dropwise addition of bromoacetonitrile. Ring closure of the
Before introducing a substituted amino group on the skeleton of
the targeted products, synthesis of the unsubstituted 4-amino
derivatives (1a and 2a) was realized in good yields (84e85%) by
strong heating (170 ꢀC for 30 min) of intermediate formimidamides
3 and 4 in the presence of formamide which played the dual role of
solvent and reactant [13]. Its temperature-dependent ability to
generate ammonia synthon and its intrinsic properties of heating
under microwave irradiation (its loss dissipation factor, tan d, is
greater than 0.5) [14] were combined in a comfortable process
constituting a safe alternative to the extreme conditions usually
described in the literature (Scheme 5) [15].
The synthesis of the 4-anilino-substituted derivatives (1bez and
2bez) consisted of heating the formimidamide derivatives 3 and 4
with various anilines in the presence of acetic acid which served as
a
relatively good solvent for heating under microwaves
Scheme 2. Retrosynthetic pathway to generate benzofuro[3,2-d]pyrimidine (1) and benzothieno[3,2-d]pyrimidine (2) derivatives.

Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
285
Scheme 3. Synthesis of 3-amino-6-methoxybenzofuran-2-carbonitrile (3). Reagents and conditions: a) 1-decanethiol, t-BuOK, DMF, 110 ꢀC, 1 h; b) BrCH2CN, K2CO3/DMF, r.t., 1.5 h; c)
80 ꢀC, 16 h.
(tan
d
¼ 0.174 at 2.45 GHz [14]) and also initiated the reaction.
Note that among the two families of tested molecules, four
benzofuro[3,2-d]pyrimidine derivatives (1a, 1e, 1i and 1o) were
judged relatively active (in the micromolar range) against two
kinases (CLK1 and DYRK1A) or one kinase (DYRK1A for 1r).
Compound 1a (entry 1 in Table 2) was the only product able to
inhibit three kinases in the micromolar (CK1 and DYRK1A) or sub-
micromolar range (CLK1). This result suggests that N-arylation of
the amine in position 4 of the pyrimidine part of the molecules may
provide inhibitory activity towards CLK1 and DYRK1A.
The most promising results were obtained with products from
the 2aez series, which showed a rather good inhibition of both
CLK1 and DYRK1A kinases with micromolar or submicromolar IC50
values for most of them. Among these compounds, 2j and 2z can be
considered as the most active products with submicromolar IC50
values against the two kinases (entries 10 and 26 in Table 3). The
values obtained for 2j are the most promising towards DYRK1A
(500 nM) and CLK1 (680 nM). On an overall aspect, IC50 values of
the 2aez series against DYRK1A and CLK1 ranged from 6.8 to
The starting mixture was irradiated at 400 W in a multimode cavity.
After 3 min, the temperature at which the solvent could be refluxed
(118 ꢀC) was reached (this time, called “the ramp period”, was not
added to the reaction time described in Table 1). The evolution of all
reactions was monitored by thin-layer chromatography and the
reaction times given corresponded to a complete disappearance of
the starting material (Table 1). A list of anilines was established,
based on the Topliss schemes [16], in the hope to maximize the
chances of synthesizing the most potent compounds as early as
possible. Twenty-five derivatives of each family (1bez and 2bez)
were rapidly obtained via Dimroth translocation of the endocyclic
and exocyclic nitrogen atoms present in the pyrimidine moiety [6].
This process led to the thermodynamically stable 4-anilino-
substituted isomers of the final products (Scheme 5).
3. Biological activities
0.50 mM. Therefore, these compounds can be considered as much
The final products were tested on five different in vitro kinase
less active than harmine (0.029
CLK1, respectively).
mM and 0.026 mM for DYRK1A and
assays CDK5/p25 (cyclin-dependent kinase), CK1
d/ε (casein kinase
1), GSK3 (Glycogen Synthase Kinase 3), DYRK1A (dual-speci-
a/b
Concerning compounds 2aez (Table 3) the main part of their
activity was linked to DYRK1A with fourteen products (2deg, 2j,
2oer, 2uex and 2z) which exhibited an inhibitory activity in the
micromolar and submicromolar ranges (8.1mM < IC50 < 0.5 mM).
For nine of these fourteen molecules, affinity for kinases was also
sometimes centred on CLK1 (products 2f, 2g, 2j, 2o, 2p, 2u, 2v, 2x
ficity tyrosine phosphorylation regulated kinase) and CLK1 (cdc2-
like kinase 1) to evaluate their inhibition potency [17e19]. All
compounds were first tested at a final concentration of 10
Compounds showing less than 50% inhibition were considered as
inactive (IC50 > 10 M). Compounds displaying more than 50%
inhibition at 10 M were next tested over a wide range of
concentrations (usually 0.01e10 M), and IC50 values were deter-
mined from the doseeresponse curves (Sigma-Plot). Harmine
(entry 27 in Tables 2 and 3) is a -carboline alkaloid known to be
mM.
m
m
and 2z: 6.8mM < IC50 < 0.68 mM).
m
Comparison of DYRK1A inhibition of the most active
compounds of the two series (1a, 1e,1i,1o and 1r in Table 2 and 2fe
g, 2j, 2oer, 2uex and 2z in Table 2) with their analogues (e.g. 1e/2e,
1i/2i, etc.) showed that in most cases, benzothieno[3,2-d]pyrimi-
dine derivatives (2) were more active than their benzofuro[3,2-d]
pyrimidine congeners except in the case of 1e/2e for which the
b
a potent inhibitor of DYRK1A [1,20]. It was also tested as positive
control and its IC50 value was compared with those obtained for the
compounds under study.
Results given in Tables 2 and 3 demonstrated that none of the
tricyclic derivatives prepared in this work showed any affinity
against CDK5/p25 and GSK3. On a general aspect, the benzofuro
[3,2-d]pyrimidine and benzothieno[3,2-d]pyrimidine derivatives
(1bez and 2bez) were completely inactive on the casein kinase 1
(CK1), except for compounds 1a (entry 1 in Table 2) and 2u (entry
oxygenated partner (1e, 0.88
sulfur containing analogue (2e, 7.1
m
M DYRK1A) was more active than its
M DYRK1A).
m
All these results demonstrated that it is difficult to define any
role for the various substituents of the amine located at position 4
of the pyridine ring. However, it is interesting to note that the
presence of two substituents on the aromatic rings (2f, 2g, 2j, 2r, 2u
and 2v in Table 2) resulted in micromolar and submicromolar
affinity for DYRK1A and also for CLK1 in a large number of the
21 in Table 3) for which micromolar IC50 values (1.9 and 3.9
respectively) were observed. On this point of view, 1a showed
a similar activity on CK1 than harmine (1.5 M).
mM,
m
Scheme 4. Synthesis of benzothiophene analogue (4). Reagents and conditions: a) CuCN, DMF 160 ꢀC, 2 h; b) HSCH2CH2CN, KOH/DMF, 0 ꢀC, 15 min then BrCH2CN, 0 ꢀC, 2 h.

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Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
Scheme 5. General synthesis of benzofuro[3,2-d]pyrimidines (1aez) and benzothieno[3,2-d]pyrimidine (2aez) derivatives.
active products, although the observed affinities were lower for
CLK1. On the contrary, the presence of one substituent on the N-aryl
moiety abolished the inhibitory activity for DYRK1A and all the
other kinases tested.
a PerkinElmer Spectrum 100 Series FT-IR spectrometer. 1H, 13C NMR
spectra were recorded on a Bruker DXP 300 spectrometer at 300,
75 MHz, respectively and a Bruker AVANCE 400 MHz high resolu-
tion NMR spectrometer at 400,100 MHz, respectively. Multiplicities
were abbreviated as follows: singlet (s), doublet (d), triplet (t),
multiplet (m), and broad (br). Reactions were monitored by TLC
analysis using Merck silica gel 60F-254 thin layer plates. Column
chromatography was carried out on silica gel Merck 60 (70e230
mesh ASTM). Elemental analyses were found within ꢁ0.4% of the
theoretical values. Mass spectra were performed by the Mass
Spectrometry Laboratory of the University of Rouen. Mass spectra
(EI) were recorded with a Waters ZQ 2000 and a Waters LCP 1er XR
spectrometer.
In view of the results of this study, we consider that
the tricyclic N-aryl-7-methoxybenzo[b]thieno[3,2-d]pyrimidin-4-
amine analogues (2) constitute a promising source of inspiration
for the synthesis of novel bioactive molecules. Synthetic trans-
formations will be envisioned and factors governing their dual
activity towards CKL1 and DYRK1A will be further investigated.
We are pursuing the SAR study and based on the results and
already established co-crystal structures of DYRK1A and CLKs [21],
we should be able to establish a precise molecular model of the
interaction of our inhibitors with their targets.
Microwave experiments were conducted in
a commercial
microwave reactor especially designed for synthetic chemistry.
RotoSYNTHÔ (Milestone S.r.l. Italy) is a multi-mode cavity with
a microwave power delivery system ranging from 0 to 1200 W. The
temperatures of the reactions were mainly monitored via contact-
less infrared pyrometer which was calibrated in control experi-
ments with a fibre-optic contact thermometer protected in a Teflon
coated ceramic well inserted directly in the reaction mixture. Open
vessel experiments were carried out in a 100e250 mL round
bottom flask fitted with a reflux condenser. The vessel contents
were stirred by means of an adjustable rotating magnetic plate
located below the floor of the microwave cavity and a Teflon-coated
magnetic stir bar inside the vessel. Temperature and power profiles
were monitored in both cases through the EASY-Control software
provided by the manufacturer.
4. Conclusion
The synthesis of a library of novel N-aryl-7-methoxybenzo[b]
furo[3,2-d]pyrimidin-4-amines
(1)
and
their
N-aryl-7-
methoxybenzo[b]thieno[3,2-d]pyrimidin-4-amine analogues (2)
was realized under microwaves via a Dimroth rearrangement. Good
control of the reaction parameters allowed efficient heating of the
reaction mixture, resulting in short reaction times and good yields.
The inhibitory potency of the final products against five kinases was
evaluated. Our study demonstrates that N-aryl-7-methoxybenzo[b]
thieno[3,2-d]pyrimidin-4-amine derivatives are particularly
promising for the development of new dual inhibitors of CLK1 and
DYRK1A kinases. The most effective compounds towards these two
kinase families are the benzothieno[3,2-d]pyrimidines 2j and 2z
which showed interesting submicromolar inhibition and selectivity
towards CLK1 and DYRK1A over the other tested kinases. These
results are the starting point of a larger program within our group,
in the hope to lead to the discovery of novel kinase inhibitors with
potential therapeutic application in Alzheimers’ disease and Down
Syndrome.
5.1.1. Synthetic route for the preparation of 3-amino-6-
methoxybenzofuran-2-carbonitrile (3)
5.1.1.1. 2-Hydroxy-4-methoxybenzonitrile (7). A mixture of 1-
decanethiol (6.41 g, 36.77 mmol) in N,N-dimethylformamide
(50 mL) was cooled to 5e10 ꢀC under nitrogen atmosphere. When
the internal temperature was below 10 ꢀC, solid KOtBu (5.16 g,
45.96 mmol) was added in one portion after 10 min, the reaction
mass was allowed to warm to 20e25 ꢀC. After 15 min, 2,4-
dimethoxybenzonitrile (5.00 g, 30.64 mmol) was added and the
reaction was heated to 110 ꢀC for 60 min. TLC analysis (petroleum
ether/ethyl acetate 1:1 as mobile phase) showed complete reaction.
The mixture was allowed to cool to 20e25 ꢀC and then poured into
ice water (150 mL). To the flask was added 1 N HCl dropwise to
5. Experimental section
5.1. Chemistry
Melting points of powder compounds were measured on
an STUART-Advanced apparatus. IR spectra were recorded on

Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
287
Table 1
Synthesis of benzofuro[3,2-d]pyrimidine and benzothieno[3,2-d]pyrimidine derivatives (1bez and 2bez).a
Compound
R
1
2
1
2
Time (min)
Yieldb (%)
62
Time (min)
Yieldb (%)
67
Time (min)
Yieldb (%)
56
Time (min)
Yieldb (%)
b
c
20
10
45
25
o
p
120
60
135
90
68
69
99
60
80
64
64
70
d
30
45
q
60
120
50
e
f
45
80
99
99
60
55
92
r
s
60
75
99
73
180
120
77
66
135
g
80
80
72
74
135
90
83
84
t
40
60
78
77
90
73
73
h
u
180
i
j
80
80
65
63
135
135
84
74
v
150
15
67
80
240
25
75
72
w
k
l
90
40
72
61
90
60
73
54
x
y
90
90
71
55
150
120
67
62
m
n
40
40
65
71
30
60
59
61
z
90
20c
215
16c
a
Reaction was performed under microwaves (
Yield of isolated product.
mW) at 400 W, on a 0.5 mmol scale from 5 or 6 with 1 equiv of aniline (MultiSYNTHÔ from Milestone S.r.l. Italy).
b
c
Temperature of reaction was increased to 140 ꢀC.
bring the pH to 1 followed by the addition of water (150 mL). The
aqueous phase was extracted with ethyl acetate (3 ꢂ 100 mL), and
the combined organic extracts were washed with (2 ꢂ 100 mL)
saturated brine and dried over Na2SO4. The solvent was removed
under vacuum to give a free flowing solid. To this solid was added
100 mL heptane and stirred for 60 min. The solid obtained was
filtered off and washed with 50 mL heptane to give 2-hydroxy-4-
methoxybenzonitrile (7) as a grey solid (4.39 g, 96%); mp 174e
175 ꢀC (lit. [8]: 169e172 ꢀC); IR (KBr) nmax (cmꢃ1): 3213 (OH),
2226 (CN), 1601, 1595, 1514, 1465, 1449, 1435, 1379, 1323, 1277, 1211,
1169, 1103, 1026, 829, 800; 1H NMR (400 MHz, DMSO-d6):
(br s,1H, OH), 7.51 (d, 1H, J ¼ 8.4 Hz, H-6), 6.56e6.47 (m, 2H, H-3, H-
5), 3.77 (s, 3H, OCH3); 13C NMR (100 MHz, DMSO-d6):
164.0, 161.9,
134.4, 117.4, 106.7, 101.0, 91.2, 55.5; HRMS m/z calcd for C8H7NO2
149.0477 [M] found 149.0474.
d 11.08
d
5.1.1.2. 3-Amino-6-methoxybenzofuran-2-carbonitrile (3). To a sus-
pension of 2-hydroxy-4-methoxybenzonitrile (3.50 g, 23.46 mmol)
and K2CO3 (8.11 g, 58.66 mmol) in DMF (80 mL) bromoacetonitrile
(1.80 mL, 25.81 mmol) was added at room temperature and the

288
Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
174 ꢀC; IR (KBr) nmax (cmꢃ1): 3447 (NH2), 3358 (NH2), 3223, 2191
Table 2
Kinase activity of benzofuro[3,2-d]pyrimidine derivatives (1aez).a
(CN), 1643, 1620, 1605, 1570, 1500, 1448, 1435, 1406, 1285, 1200, 1148,
1103, 1014, 945, 813; 1H NMR (400 MHz, DMSO-d6):
d 7.79 (d, 1H,
Entry
Compound
CDK5
CK1
1.9
CLK1
0.41
>10
>10
>10
DYRK1A
GSK3
J ¼ 8.8 Hz, H-4), 7.09 (d, 1H, J ¼ 1.6 Hz, H-7), 6.95 (dd, 1H, J1 ¼ 1.6 Hz,
1
2
3
4
5
6
7
8
1a
1b
1c
1d
1e
1f
1g
1h
1i
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
1.1
>10
>10
>10
0.88
>10
>10
>10
2.8
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
J2 ¼ 8.8 Hz, H-5), 6.62 (br s, 2H, NH2), 3.85 (s, 3H, OCH3); 13C NMR
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
(100 MHz, DMSO-d6):
d 161.5, 155.9, 143.0, 121.8, 115.0, 114.1, 112.6,
106.4, 95.9, 55.9; MS (ESI) m/z (%): 189.1 (100) [M þ H]þ. Anal. calcd
for C10H8N2O2: C, 63.82; H, 4.28; N, 14.89. Found: C, 64.05; H, 4.30; N,
14.94.
1.5
>10
>10
>10
2
9
5.1.2. Synthetic route for the preparation of 3-amino-6-methoxybenzo-
thiophene-2-carbonitrile (4)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
1j
1k
1l
1m
1n
1o
1p
1q
1r
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
3.2
>10
>10
3.1
>10
>10
>10
>10
>10
>10
>10
>10
0.029
5.1.2.1. 4-Methoxy-2-nitrobenzonitrile
(8). 3-Nitro-4-bromoan-
isole (5.00 g, 21.54 mmol) was dissolved in anhydrous DMF and
CuCN (2.89 g, 32.32 mmol) was added. The mixture was heated at
160 ꢀC for 2 h. After cooling it was poured into crushed ice and
a precipitate was formed, which was filtered and dried under
vacuum. The greenish solid obtained was dissolved in CHCl3 and
the solution was filtered. The solvent removal of the filtrate gave
a yellow solid (2.88 g, 75%); mp 129e130 ꢀC (lit. [9]: 129e131 ꢀC);
IR (KBr) nmax (cmꢃ1): 3103, 2230 (CN), 1616, 1529, 1500, 1443, 1348,
1311, 1285, 1248, 1188, 1067, 1020, 899, 840, 808; 1H NMR
4.2
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
1s
1t
1u
1v
1w
1x
1y
(300 MHz, CDCl3):
d 7.84e7.79 (m, 2H, H-3 and H-6), 7.28 (dd, 1H,
J1 ¼ 2.4 Hz, J2 ¼ 9.0 Hz, H-5), 3.99 (s, 3H, OCH3); 13C NMR (75 MHz,
1z
Harmine
CDCl3):
d 163.2, 150.1, 136.6, 119.9, 115.2, 111.1, 99.4, 56.5; MS (ESI)
1.5
0.026
m/z (%): 179.1 (100) [M þ H]þ. Anal. calcd for C8H6N2O3: C, 53.94; H,
Values in bold represents the most significant data in the table.
3.39; N, 15.73. Found: C, 54.11; H, 3.40; N, 15.75.
a
IC50 values are reported in mM.
5.1.2.2. 3-Amino-6-methoxybenzo[b]thiophene-2-carbonitrile
(4).
mixture was stirred at room temperature for 1.5 h. The reaction
mixture was then heated at 80 ꢀC for 16 h. The mixture was poured
into water and extracted with dichloromethane. The organic layer
was washed with brine, then dried, and evaporated to give a pale
brown powder which was purified with silica gel column chroma-
tography using diethylether/petroleum ether (5:5, v/v). The desired
product (3) was isolated as a white powder (3.49 g, 79%); mp 173e
A solution of potassium hydroxide (2.36 g, 42.10 mmol) in water
(8 mL) was added dropwise to a stirred and cold solution (ice bath)
containing 4-methoxy-2-nitrobenzonitrile (2.50 g,14.03 mmol) and
3-mercaptopropionitrile (1.47 g, 16.84 mmol) in DMF (30 mL). The
cold mixture was stirred for 15 min and bromoacetonitrile (1.47 mL,
21.05 mmol) was added dropwise. After 2 h at 0 ꢀC, the mixture was
poured into ice water. The crude product was collected by filtration
and purified with silica gel column chromatography using
dichloromethane/petroleum ether (5:5, v/v). The desired product
(4) was isolated as a white powder (1.58 g, 55%); mp 145e148 ꢀC; IR
(KBr) nmax (cmꢃ1): 3445 (NH2), 3333 (NH2), 3233, 2187 (CN), 1632,
1599,1572,1528,1487,1427,1415,1385,1340,1273,1246,1200,1182,
Table 3
Kinase activity of benzothieno[3,2-d]pyrimidine derivatives (2aez).a
Entry
Compound
CDK5
CK1
CLK1
DYRK1A
GSK3
1
2
3
4
5
6
7
8
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
2k
2l
2m
2n
2o
2p
2q
2r
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
2.8
5.1
>10
>10
0.68
>10
>10
>10
>10
3.1
6.1
>10
>10
>10
>10
1.6
2.3
>10
6.8
>10
>10
>10
>10
6.1
7.1
0.93
3.9
>10
>10
0.5
>10
>10
>10
>10
0.61
2
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
1049, 1018, 891, 837, 823, 812; 1H NMR (400 MHz, DMSO-d6):
d 8.02
(d,1H, J ¼ 8.8 Hz, H-4), 7.48 (d,1H, J ¼ 1.6 Hz, H-7), 7.09e7.06 (m, 3H,
H-5 and NH2), 3.86 (s, 3H, OCH3); 13C NMR (100 MHz, DMSO-d6):
d
160.5, 152.4, 141.2, 124.1, 123.9, 116.7, 114.7, 105.7, 70.5, 55.8; MS
(ESI) m/z (%): 205.1 (100) [M þ H]þ. Anal. calcd for C10H8N2OS: C,
58.80; H, 3.95; N, 13.72. Found: C, 59.03; H, 3.97; N, 13.76.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
5.1.3. General procedure for the synthesis of N,N-
dimethylformimidamides derivatives (5 and 6)
A mixture of starting cyanoenamine (1.0 g) and N,N-dime-
thylformamide dimethylacetal (5 mL) was irradiated at 90 ꢀC
(800 W). On completion, the solution was cooled to room
temperature and the mixture was extracted with ethyl acetate. The
organic layers were washed with cold water, dried over Na2SO4,
filtered and evaporated in vacuo. A purification by column chro-
matography over silica gel using dichloromethane/petroleum ether
(5:5, v/v) as the eluent gave the desired compounds 5 and 6.
8.1
1.6
2s
2t
>10
>10
0.93
0.71
0.71
2.6
>10
0.66
0.029
2u
2v
2w
2x
2y
3.9
>10
>10
>10
>10
>10
5.1.3.1. (E)-N0-(2-Cyano-6-methoxybenzofuran-3-yl)-N,N-dime-
thylformimidamide (5). White powder (1.21 g; 99%) obtained from
3-amino-6-methoxybenzofuran-2-carbonitrile (3) after 30 min of
irradiation; mp 104e105 ꢀC; IR (KBr) nmax (cmꢃ1): 2206 (CN), 1608,
1584, 1564, 1553, 1427, 1372, 1278, 1255, 1195, 1152, 1105, 1091,
2z
Harmine
0.79
0.026
1.5
Values in bold represents the most significant data in the table.
a
IC50 values are reported in
mM.
1063, 1026, 951, 939, 828, 816; 1H NMR (300 MHz, DMSO-d6):
d 8.27

Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
289
(s, 1H, NCHN), 7.73 (d, 1H, J ¼ 8.8 Hz, H-4), 7.18 (d, 1H, J ¼ 2.1 Hz, H-
7), 6.95 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.8 Hz, H-5), 3.83 (s, 3H, OCH3), 3.11
(s, 3H, NCH3), 3.02 (s, 3H, NCH3); 13C NMR (75 MHz, DMSO-d6):
column chromatography over silica gel using
petroleum ether/ethyl acetate (100:0 to 0:100, v/v) as the eluent
to give the desired compounds (1bez).
a
gradient of
d
160.9, 156.3, 156.1, 146.1, 122.1, 115.5, 114.3, 113.9, 113.4, 95.9, 55.7,
5.1.5.1.1. 7-Methoxy-N-phenylbenzofuro[3,2-d]pyrimidin-4-
amine (1b). Yield: 62%; white powder; mp 222e223 ꢀC; IR (KBr)
nmax (cmꢃ1): 1620, 1592, 1497, 1472, 1448, 1433, 1301, 1284, 1241,
33.9 (2C); HRMS calcd for C13H14N3O2 [M þ H]þ 244.1086 found
244.1081.
1145, 1139, 1085, 1030, 823; 1H NMR (300 MHz, DMSO-d6):
d 10.04
5.1.3.2. (E)-N0-(2-Cyano-6-methoxybenzothiophen-3-yl)-N,N-dime-
thylformimidamide (6). White powder (1.26 g; 99%) obtained from
3-amino-5-methoxybenzo[b]thiophene-2-carbonitrile (4) after
30 min of irradiation; mp 116e117 ꢀC; IR (KBr) nmax (cmꢃ1): 2191
(CN), 1621, 1597, 1489, 1472, 1423, 1412, 1396, 1374, 1257, 1242, 1113,
1058, 1022, 989, 879, 838, 823; 1H NMR (300 MHz, DMSO-d6):
(s, 1H, NH), 8.60 (s, 1H, H-2), 8.03 (d, 1H, J ¼ 8.8 Hz, H-9), 7.90 (dd,
2H, J1 ¼1.0 Hz, J2 ¼ 8.4 Hz, H-ar), 7.38 (td, 2H, J1 ¼1.0 Hz, J2 ¼ 8.4 Hz,
H-ar), 7.35 (d, 1H, J ¼ 1.6 Hz, H-6), 7.16 (dd, 1H, J1 ¼ 1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 7.07 (td, 1H, J1 ¼ 1.0 Hz, J2 ¼ 8.4 Hz, H-ar), 3.94 (s,
3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 162.0, 157.5, 152.8,
146.3, 145.8, 139.3, 134.3, 128.5 (2C), 122.9, 121.9, 120.7 (2C), 115.1,
113.0, 96.9, 56.0; HRMS calcd for C17H14N3O2 [M þ H]þ 292.1086
found 292.1072.
5.1.5.1.2. 7-Methoxy-N-(p-tolyl)benzofuro[3,2-d]pyrimidin-4-
amine (1c). Yield: 99%; white powder; mp 206e207 ꢀC; IR (KBr)
nmax (cmꢃ1): 1634, 1623, 1615, 1586, 1509, 1495, 1478, 1436, 1405,
1333, 1306, 1229, 1138, 1082, 1015, 967, 820; 1H NMR (300 MHz,
d
8.14 (s, 1H, NCHN), 7.70 (d, 1H, J ¼ 8.8 Hz, H-4), 7.53 (d, 1H,
J ¼ 1.9 Hz, H-7), 7.05 (dd, 1H, J1 ¼ 1.9 Hz, J2 ¼ 8.8 Hz, H-5), 3.84 (s,
3H, OCH3), 3.11 (s, 3H, NCH3), 3.05 (s, 3H, NCH3); 13C NMR (75 MHz,
DMSO-d6):
d 160.2, 157.0, 155.9, 140.7, 127.7, 124.4, 116.6, 115.3,
105.4, 83.2, 55.7, 34.1 (2C); HRMS calcd for C13H14N3OS [M þ H]þ
260.0858 found 260.0854.
DMSO-d6):
d 9.95 (s, 1H, NH), 8.56 (s, 1H, H-2), 8.00 (d, 1H,
5.1.4. General procedure for the synthesis of furo or thieno[3,2-d]
pyrimidin-4-amine derivatives (1a and 2a)
J ¼ 8.8 Hz, H-9), 7.76 (d, 2H, J ¼ 8.4 Hz, H-ar), 7.32 (d, 1H, J ¼ 1.6 Hz,
H-6), 7.16 (d, 2H, J ¼ 8.4 Hz, H-ar), 7.12 (dd, 1H, J1 ¼ 1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 3.92 (s, 3H, OCH3), 2.29 (s, 3H, CH3); 13C NMR
A mixture of formamide (2 mL) and N,N-dimethylformimida-
mide derivatives (5 or 6) (0.1 g) was irradiated (200 W). On
completion (followed by GCeMS chromatography), the reaction
was cooled to room temperature and water was added. The solid
was filtered off, washed with water and dried. The crude solid was
purified by column chromatography over silica gel using petroleum
ether/ethyl acetate (100:0 to 0:100, v/v) as the eluent to give the
desired compounds (1a and 2a).
(75 MHz, DMSO-d6):
d 161.9, 157.5, 152.9, 145.8, 136.7, 134.4, 131.8,
131.1, 128.9 (2C), 121.9, 120.8 (2C), 115.1, 112.9, 96.9, 56.0, 20.5;
HRMS calcd for C18H16N3O2 [M þ H]þ 306.1243 found 306.1245.
5.1.5.1.3. 7-Methoxy-N-(m-tolyl)benzofuro[3,2-d]pyrimidin-4-
amine (1d). Yield: 60%; white powder; mp 200e201 ꢀC; IR (KBr)
nmax (cmꢃ1): 1620, 1596, 1469, 1455, 1433, 1332, 1299, 1281, 1268,
1238, 1136, 1020, 825; 1H NMR (300 MHz, DMSO-d6):
d 9.95 (s, 1H,
NH), 8.59 (s, 1H, H-2), 8.02 (d, 1H, J ¼ 8.8 Hz, H-9), 7.77 (s, 1H, H-ar),
7.70 (d, 1H, J ¼ 8.4 Hz, H-ar), 7.33 (d, 1H, J ¼ 1.6 Hz, H-6), 7.16 (td, 1H,
J1 ¼ 8.0 Hz, J2 ¼ 8.4 Hz, H-ar), 7.14 (dd, 1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-
8), 6.92 (d, 1H, J ¼ 8.0 Hz, H-ar), 3.93 (s, 3H, OCH3), 2.33 (s, 3H, CH3);
5.1.4.1. 7-Methoxybenzofuro[3,2-d]pyrimidin-4-amine
(1a). White
powder (0.072 g, 84%); obtained from (E)-N0-(2-cyano-6-
methoxybenzofuran-3-yl)-N,N-dimethylformimidamide (5) after
30 min of irradiation at 170 ꢀC; mp 281e282 ꢀC; IR (KBr) nmax (cmꢃ1):
3119, 1655, 1629, 1606, 1495, 1402, 1293, 1270, 1183, 1135, 1095, 1045,
13C NMR (75 MHz, DMSO-d6):
d 162.0, 157.5, 152.9, 146.3, 145.8,
139.2, 137.7, 134.3, 128.4, 123.6, 121.9, 121.2, 118.0, 115.1, 113.0, 96.9,
56.0, 21.3; HRMS calcd for C18H16N3O2 [M þ H]þ 306.1243 found
306.1247.
962, 930, 822, 815, 780; 1H NMR (300 MHz, DMSO-d6):
d 8.35 (s, 1H,
H-2), 7.93 (d, 1H, J ¼ 8.8 Hz, H-9), 7.43 (br s, 2H, NH2), 7.29 (d, 1H,
J ¼ 1.6 Hz, H-6), 7.07 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.90 (s, 3H,
5.1.5.1.4. 7-Methoxy-N-(4-methoxyphenyl)benzofuro[3,2-d]pyr-
imidin-4-amine (1e). Yield: 99%; purple powder; mp 224e225 ꢀC;
IR (KBr) nmax (cmꢃ1): 1620, 1591, 1508, 1494, 1474, 1466, 1453,
1441, 1434, 1411, 1397, 1333, 1295, 1264, 1241, 1135, 1086, 968, 819;
OCH3); 13C NMR (75 MHz, DMSO-d6):
d 161.6, 157.3, 153.4, 149.6, 145.7,
133.9, 121.7, 115.2, 112.7, 96.8, 55.9; HRMS calcd for C11H10N3O2
[M þ H]þ 216.0773 found 216.0765.
1H NMR (300 MHz, DMSO-d6):
d 9.87 (s, 1H, NH), 8.53 (s, 1H, H-2),
5.1.4.2. 7-Methoxybenzothieno[3,2-d]pyrimidin-4-amine
(2a).
8.00 (d, 1H, J ¼ 8.8 Hz, H-9), 7.74 (d, 2H, J ¼ 9.0 Hz, H-ar), 7.31 (d, 1H,
J ¼ 1.6 Hz, H-6), 7.13 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 6.95 (d,
2H, J ¼ 9.0 Hz, H-ar), 3.93 (s, 3H, OCH3), 3.76 (s, 3H, OCH3); 13C NMR
White powder (0.074 g, 85%); obtained from (E)-N0-(2-cyano-6-
methoxybenzothiophen-3-yl)-N,N-dimethylformimidamide
(6)
after 30 min of irradiation at 170 ꢀC; mp 277e278 ꢀC; IR (KBr) nmax
(cmꢃ1): 3064, 1564, 1518, 1493, 1476, 1457, 1443, 1433, 1287, 1263,
1232, 1031, 880, 834, 823, 781, 730; 1H NMR (300 MHz, DMSO-d6):
(75 MHz, DMSO-d6): d 161.8, 157.4, 155.3, 152.9, 146.0, 145.9, 134.2,
132.1, 122.7 (2C), 121.8, 115.1, 113.7 (2C), 112.9, 96.9, 56.0, 55.2;
HRMS calcd for C18H16N3O3 [M þ H]þ 322.1192 found 322.1192.
5.1.5.1.5. 7-Methoxy-N-(3,4-dimethoxyphenyl)benzofuro[3,2-d]
pyrimidin-4-amine (1f). Yield: 99%; purple powder; mp 182e
183 ꢀC; IR (KBr) nmax (cmꢃ1): 1635, 1621, 1590, 1507, 1466, 1442,
1427, 1402, 1363, 1299, 1256, 1238, 1227, 1199, 1135, 1091, 1024, 987,
d
8.47 (s, 1H, H-2), 8.14 (d, 1H, J ¼ 8.8 Hz, H-9), 7.72 (d, 1H, J ¼ 1.6 Hz,
H-6), 7.45 (br s, 2H, NH2), 7.15 (dd, 1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-8),
3.89 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
160.7, 158.2,
d
155.5, 115.1, 141.6, 127.2, 123.8, 114.8, 111.8, 106.2, 55.7; HRMS calcd
for C11H10N3OS [M þ H]þ 232.0545 found 232.0556.
839, 805; 1H NMR (300 MHz, DMSO-d6):
d 9.85 (s, 1H, NH), 8.55 (s,
1H, H-2), 7.99 (d, 1H, J ¼ 8.8 Hz, H-9), 7.53 (d, 1H, J ¼ 1.7 Hz, H-ar),
7.43 (dd, 1H, J1 ¼1.7 Hz, J2 ¼ 8.7 Hz, H-ar), 7.31 (d, 1H, J ¼ 1.6 Hz, H-
6), 7.13 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 6.95 (d, 1H, J ¼ 8.7 Hz,
5.1.5. General procedures for the synthesis of furo or thieno[3,2-d]
pyrimidine derivatives (1bez and 2bez)
5.1.5.1. Synthesis of N-aryl-7-methoxybenzofuro[3,2-d]pyrimidin-4-
H-ar), 3.93 (s, 3H, OCH3), 3.77 (s, 3H, OCH3), 3.76 (s, 3H, OCH3); 13
C
amines
(1bez). A
mixture
of
(E)-N0-(2-cyano-5-
NMR (75 MHz, DMSO-d6): d 161.8, 157.4, 152.9, 148.4, 145.9, 144.9,
methoxybenzofuran-3-yl)-N,N-dimethylformimidamide (5) (0.1 g,
0.38 mmol) and appropriate aniline (1.0 equiv) in acetic acid
(2 mL) was irradiated at 118 ꢀC (400 W). On completion (followed
by thin-layer chromatography), the reaction was cooled to room
temperature and water was added. The solid was filtered off,
washed with water and dried. The crude solid was purified by
134.2, 132.6, 121.8 (2C), 115.1, 113.0, 112.9, 111.9, 106.4, 96.8, 55.9,
55.7, 55.4; HRMS calcd for C19H18N3O4 [M þ H]þ 352.1297 found
352.1298.
5.1.5.1.6. 7-Methoxy-N-(3,5-dimethoxyphenyl)benzofuro[3,2-d]
pyrimidin-4-amine (1g). Yield: 72%; grey powder; mp 172e173 ꢀC;
IR (KBr) nmax (cmꢃ1): 1598, 1573, 1483, 1451, 1434, 1415, 1248, 1238,

290
Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
1203, 1191, 1153, 1132, 1090, 1070, 1055, 1026, 944, 827, 821; 1H
NMR (300 MHz, DMSO-d6): 9.96 (s, 1H, NH), 8.63 (s, 1H, H-2), 8.02
5.1.5.1.12. N-(4-Chlorophenyl)-7-methoxybenzofuro[3,2-d]pyr-
imidin-4-amine (1m). Yield: 65%; white powder; mp 253e254 ꢀC;
IR (KBr) nmax (cmꢃ1): 1622, 1583, 1515, 1491, 1473, 1435, 1402,
1363, 1302, 1241, 1224, 1144, 1085, 1035, 1013, 968, 852, 821, 810; 1H
d
(d, 1H, J ¼ 8.8 Hz, H-8), 7.32 (d, 1H, J ¼ 1.6 Hz, H-6), 7.24 (d, 2H,
J ¼ 2.1 Hz, H-ar), 7.14 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-9), 6.25 (t,
1H, J ¼ 2.1 Hz, H-ar), 3.94 (s, 3H, OCH3), 3.76 (s, 6H, OCH3); 13C NMR
NMR (300 MHz, DMSO-d6):
d 10.19 (s, 1H, NH), 8.62 (s, 1H, H-2),
(75 MHz, DMSO-d6):
d
162.0, 160.4 (2C), 157.5, 152.8, 146.3, 145.6,
8.03 (d,1H, J ¼ 8.8 Hz, H-9), 7.96 (d, 2H, J ¼ 9.0 Hz, H-ar), 7.43 (d, 2H,
J ¼ 9.0 Hz, H-ar), 7.34 (d,1H, J ¼ 1.6 Hz, H-6), 7.15 (dd,1H, J1 ¼1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 3.94 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
141.0, 134.3, 121.9, 115.0, 113.0, 98.9 (2C), 96.9, 94.5, 56.0, 55.1 (2C);
HRMS calcd for C19H18N3O4 [M þ H]þ 352.1297 found 352.1295.
5.1.5.1.7. 7-Methoxy-N-(3,4,5-trimethoxyphenyl)benzofuro[3,2-d]
pyrimidin-4-amine (1h). Yield: 74%; grey powder; mp 203e204 ꢀC;
IR (KBr) nmax (cmꢃ1): 1638, 1625, 1592, 1508, 1451, 1430, 1413, 1237,
1125, 1086, 1028, 1009, 998, 830, 819; 1H NMR (300 MHz, DMSO-
d
162.1,157.6, 152.8,146.5,145.4,138.4,134.3,128.4 (2C),126.4,121.9
(2C), 115.0, 113.0, 106.8, 96.9, 56.0; HRMS calcd for C17H13N3O2Cl
[M þ H]þ 326.0696 found 326.0706.
5.1.5.1.13. N-(3-Chlorophenyl)-7-methoxybenzofuro[3,2-d]pyr-
imidin-4-amine (1n). Yield: 71%; white powder; mp 220e221 ꢀC;
IR (KBr) nmax (cmꢃ1): 1634, 1620, 1602, 1578, 1566, 1519, 1476,
1471, 1445, 1435, 1419, 1357, 1331, 1288, 1239, 1138, 1093, 1082, 971,
d6):
d
9.98 (s, 1H, NH), 8.60 (s, 1H, H-2), 8.01 (d, 1H, J ¼ 8.8 Hz, H-9),
7.32 (d, 1H, J ¼ 1.6 Hz, H-6), 7.31 (s, 2H, H-ar), 7.14 (dd, 1H,
J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.93 (s, 3H, OCH3), 3.80 (s, 6H, OCH3),
3.66 (s, 3H; OCH3); 13C NMR (75 MHz, DMSO-d6):
d
162.0, 157.5,
878, 834, 822; 1H NMR (300 MHz, DMSO-d6):
d 10.24 (s, 1H, NH),
152.9, 152.5 (2C), 146.2, 145.7, 135.4, 134.3, 133.3, 121.9, 115.1, 113.0,
98.7 (2C), 96.9, 60.1, 56.0, 55.8 (2C); HRMS calcd for C20H20N3O5
[M þ H]þ 382.1403 found 382.1395.
8.66 (s, 1H, H-2), 8.16 (s, 1H, H-ar), 8.03 (d, 1H, J ¼ 8.8 Hz, H-9), 7.84
(d, 1H, J ¼ 7.6 Hz, H-ar), 7.39 (td, 1H, J1 ¼ 7.6 Hz, J2 ¼ 8.0 Hz, H-ar),
7.35 (d,1H, J ¼ 1.6 Hz, H-6), 7.16 (dd,1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-8),
7.15 (d, 1H, J ¼ 8.0 Hz, H-ar), 3.94 (s, 3H, OCH3); 13C NMR (75 MHz,
5.1.5.1.8. N-(Benzo[d][1,3]dioxol-5-yl)-7-methoxybenzofuro[3,2-
d]pyrimidin-4-amine (1i). Yield: 65%; black powder; mp 233e
234 ꢀC; IR (KBr) nmax (cmꢃ1): 1649, 1631, 1608, 1500, 1488, 1475,
1450, 1435, 1329, 1274, 1241, 1192, 1145, 1085, 1036, 1027, 936, 832,
DMSO-d6):
d 162.1, 157.6, 152.7, 146.7, 145.3, 141.0, 134.3, 132.9,
130.2, 122.3, 122.0, 119.6, 118.7, 114.9, 113.0, 96.9, 56.0; HRMS calcd
for C17H13N3O2Cl [M þ H]þ 326.0696 found 326.0699.
800; 1H NMR (300 MHz, DMSO-d6):
d
9.91 (s, 1H, NH), 8.55 (s, 1H,
5.1.5.1.14. N-(2-Chlorophenyl)-7-methoxybenzofuro[3,2-d]pyr-
imidin-4-amine (1o). Yield: 56%; white powder; mp 182e183 ꢀC; IR
(KBr) nmax (cmꢃ1): 1615, 1591, 1462, 1444, 1430, 1384, 1332, 1304,
1292, 1279, 1259, 1134, 1084, 1019, 930, 826, 785; 1H NMR
H-2), 8.01 (d, 1H, J ¼ 8.8 Hz, H-9), 7.54 (d, 1H, J ¼ 2.2 Hz, H-ar), 7.32
(d, 1H, J ¼ 1.6 Hz, H-6), 7.28 (dd, 1H, J1 ¼ 2.2 Hz, J2 ¼ 8.4 Hz, H-ar),
7.13 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 6.92 (d, 1H, J ¼ 8.4 Hz, H-
ar), 6.02 (s, 2H, CH2), 3.93 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-
(300 MHz, DMSO-d6):
d 9.68 (s, 1H, NH), 8.47 (s, 1H, H-2), 8.03 (d,
d6):
d
161.9, 157.4,152.9,146.9,146.0,145.8,142.9,134.2,133.4,121.9,
1H, J ¼ 8.8 Hz, H-9), 7.67 (dd, 1H, J1 ¼ 1.4 Hz, J2 ¼ 7.9 Hz, H-ar), 7.58
(dd, 1H, J1 ¼ 1.4 Hz, J2 ¼ 7.8 Hz, H-ar), 7.42 (td, 1H, J1 ¼ 1.4 Hz,
J2 ¼ 7.8 Hz, H-ar), 7.35 (d, 1H, J ¼ 1.6 Hz, H-6), 7.32 (td, 1H,
J1 ¼1.4 Hz, J2 ¼ 7.9 Hz, H-ar), 7.12 (dd, 1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-
115.1, 113.8, 112.9, 107.9, 103.2, 101.0, 96.9, 56.0; HRMS calcd for
C
18H14N3O4 [M þ H]þ 336.0984 found 336.0978.
5.1.5.1.9. N-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-7-
methoxybenzofuro[3,2-d]pyrimidin-4-amine (1j). Yield: 63%; purple
powder; mp 213e214 ꢀC; IR (KBr) nmax (cmꢃ1): 1647, 1624, 1597,
1497, 1472, 1450, 1445, 1298, 1283, 1241, 1204, 1140, 1067, 1025, 845,
8), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 162.1, 157.7,
153.0, 146.8, 146.6, 136.4, 134.2, 129.9, 129.7, 128.3, 127.6, 127.2,
121.9, 114.8, 113.2, 96.9, 56.0; HRMS calcd for C17H13N3O2Cl
[M þ H]þ 326.0696 found 326.0690.
838, 821, 807; 1H NMR (300 MHz, DMSO-d6):
d 9.85 (s,1H, NH), 8.55
(s,1H, H-2), 8.00 (d,1H, J ¼ 8.8 Hz, H-9), 7.50 (d,1H, J ¼ 1.8 Hz, H-ar),
7.31 (d, 1H, J ¼ 1.6 Hz, H-6), 7.29 (dd, 1H, J1 ¼ 1.8 Hz, J2 ¼ 8.6 Hz, H-
ar), 7.14 (dd, 1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-8), 6.84 (d, 1H, J ¼ 8.6 Hz,
H-ar), 4.25 (br s, 4H, CH2), 3.93 (s, 3H, OCH3); 13C NMR (75 MHz,
5.1.5.1.15. N-(3,4-Dichlorophenyl)-7-methoxybenzofuro[3,2-d]
pyrimidin-4-amine (1p). Yield: 64%; white powder; mp 249e
250 ꢀC; IR (KBr) nmax (cmꢃ1): 1635, 1622, 1598, 1580, 1559, 1509,
1468, 1401, 1359, 1302, 1284, 1273, 1138, 1130, 1093, 1025, 973, 867,
DMSO-d6):
d
161.9, 157.4, 152.9, 145.9, 145.8, 142.8, 139.3, 134.2,
841, 813, 803; 1H NMR (300 MHz, DMSO-d6):
d 10.34 (s, 1H, NH),
132.8, 121.8, 116.6, 115.1, 114.1, 112.9, 110.0, 96.9, 64.2, 63.9, 55.9;
HRMS calcd for C19H16N3O4 [M þ H]þ 350.1141 found 350.1132.
5.1.5.1.10. N-(4-Fluorophenyl)-7-methoxybenzofuro[3,2-d]pyr-
imidin-4-amine (1k). Yield: 72%; white powder; mp 250e251 ꢀC; IR
(KBr) nmax (cmꢃ1): 1639, 1621, 1598, 1507, 1493, 1482, 1449, 1436,
1305, 1295, 1239, 1208, 1138, 1085, 838, 812; 1H NMR (300 MHz,
8.68 (s, 1H, H-2), 8.36 (d, 1H, J ¼ 2.5 Hz, H-ar), 8.03 (d, 1H, J ¼ 8.8 Hz,
H-9), 7.90 (dd, 1H, J1 ¼ 2.5 Hz, J2 ¼ 8.9 Hz, H-ar), 7.62 (d, 1H,
J ¼ 8.9 Hz, H-ar), 7.33 (d,1H, J ¼ 1.6 Hz, H-6), 7.15 (dd,1H, J1 ¼1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 3.94 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d
162.2, 157.7, 152.7, 146.8, 145.1, 139.7, 134.3, 130.7, 130.4, 123.9,
122.0, 121.2, 120.2, 114.9, 113.1, 96.9, 56.0; HRMS calcd for
DMSO-d6):
d
10.08 (s, 1H, NH), 8.57 (s, 1H, H-2), 8.01 (d, 1H,
C
17H12N3O2Cl2 [M þ H]þ 360.0307 found 360.0312.
J ¼ 8.8 Hz, H-9), 7.88 (d, 2H, J ¼ 8.7 Hz, H-ar), 7.33 (d, 1H, J ¼ 1.6 Hz,
5.1.5.1.16. N-(3,5-Dichlorophenyl)-7-methoxybenzofuro[3,2-d]
H-6), 7.20e7.16 (m, 2H, H-ar), 7.14 (dd,1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-
pyrimidin-4-amine (1q). Yield: 70%; white powder; mp 234e
235 ꢀC; IR (KBr) nmax (cmꢃ1): 1625, 1576, 1560, 1472, 1449, 1440,
1407, 1394, 1332, 1086, 1025, 985, 847, 822, 815, 809; 1H NMR
8), 3.93 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 162.0, 157.5,
152.8, 146.3, 145.7, 135.6, 135.5, 134.2, 122.6, 122.4, 121.9, 115.3,
115.0, 114.9, 113.0, 96.9, 56.0; HRMS calcd for C17H13N3O2F [M þ H]þ
310.0992 found 310.0988.
(300 MHz, DMSO-d6):
d 10.41 (s, 1H, NH), 8.72 (s, 1H, H-2), 8.11 (d,
2H, J ¼ 1.8 Hz, H-ar), 8.05 (d, 1H, J ¼ 8.8 Hz, H-9), 7.35 (d, 1H,
J ¼ 1.6 Hz, H-6), 7.27 (t, 1H, J ¼ 1.8 Hz, H-ar), 7.17 (dd, 1H, J1 ¼1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 3.95 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.1.11. N-(4-Bromophenyl)-7-methoxybenzofuro[3,2-d]pyr-
imidin-4-amine (1l). Yield: 61%; white powder; mp 254e255 ꢀC; IR
(KBr) nmax (cmꢃ1): 1621, 1579, 1563, 1513, 1473, 1436, 1399, 1362,
1301, 1284, 1273, 1237, 1224, 1143, 1094, 1072, 1033, 1008, 968, 807;
d
162.3, 157.7, 152.6, 147.0, 144.9, 142.0, 134.3, 133.8 (2C), 122.0,
121.5, 118.0 (2C), 114.8, 113.1, 96.9, 56.0; HRMS calcd for
1H NMR (300 MHz, DMSO-d6):
d
10.18 (s, 1H, NH), 8.62 (s, 1H, H-2),
C
17H12N3O2Cl2 [M þ H]þ 360.0307 found 360.0303.
8.03 (d, 1H, J ¼ 8.8 Hz, H-9), 7.91 (d, 2H, J ¼ 8.9 Hz, H-ar), 7.55 (d, 2H,
J ¼ 8.9 Hz, H-ar), 7.34 (d,1H, J ¼ 1.6 Hz, H-6), 7.15 (dd, 1H, J1 ¼1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 3.94 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.1.17. N-(2,4-Dichlorophenyl)-7-methoxybenzofuro[3,2-d]
pyrimidin-4-amine (1r). Yield: 99%; yellow powder; mp 206e
207 ꢀC; IR (KBr) nmax (cmꢃ1): 1623, 1514, 1498, 1455, 1403, 1332,
1305, 1240, 1138, 1082, 1048, 1021, 970, 870, 828, 818, 812; 1H NMR
d
162.1, 157.6, 152.7, 146.6, 145.4, 138.8, 134.3, 131.3 (2C), 122.3 (2C),
122.0, 115.0, 114.3, 113.0, 96.9, 56.0; HRMS calcd for C17H13N3O2Br
(300 MHz, DMSO-d6):
1H, J ¼ 8.8 Hz, H-9), 7.75 (d, 1H, J ¼ 2.4 Hz, H-ar), 7.70 (d, 1H,
d 9.78 (s, 1H, NH), 8.49 (s, 1H, H-2), 8.01 (d,
[M þ H]þ 370.0191 found 370.0197.

Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
291
J ¼ 8.6 Hz, H-ar), 7.49 (dd, 1H, J1 ¼ 2.4 Hz, J2 ¼ 8.6 Hz, H-ar), 7.35
(d,1H, J ¼ 1.6 Hz, H-6), 7.13 (dd,1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.92
5.1.5.1.23. 4-[(7-Methoxybenzofuro[3,2-d]pyrimidin-4-yl)amino]
benzonitrile (1x). Yield: 71%; white powder; mp > 300 ꢀC; IR (KBr)
nmax (cmꢃ1): 2223 (CN), 1628, 1607, 1583, 1517, 1506, 1498, 1475,
1401, 1364, 1304,1285, 1240,1176, 1140, 1094, 970, 853, 832, 816; 1H
(s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 162.1, 157.8, 152.9,
147.0, 146.3, 134.7, 134.2, 130.8, 130.4, 129.4, 129.1, 127.7, 121.9, 114.7,
113.3, 96.9, 56.0; HRMS calcd for C17H12N3O2Cl2 [M þ H]þ 360.0307
found 360.0309.
NMR (300 MHz, DMSO-d6):
d 10.55 (s, 1H, NH), 8.71 (s, 1H, H-2),
8.17 (d, 2H, J ¼ 8.7 Hz, H-ar), 8.06 (d, 1H, J ¼ 8.8 Hz, H-9), 7.82 (d, 2H,
J ¼ 8.7 Hz, H-ar), 7.35 (d,1H, J ¼ 1.6 Hz, H-6), 7.16 (dd,1H, J1 ¼1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 3.94 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.1.18. N-(3-Chloro-4-fluorophenyl)-7-methoxybenzofuro[3,2-
d]pyrimidin-4-amine (1s). Yield: 73%; white powder; mp 229e
230 ꢀC; IR (KBr) nmax (cmꢃ1): 1638, 1622, 1437, 1472, 1436, 1400,
1360, 1303, 1281, 1256, 1235, 1204, 1138, 1091, 1030, 976, 870, 856,
d
162.3, 157.8, 152.6, 147.3, 144.8, 143.9, 134.5, 133.0 (2C), 122.1, 119.8
(2C),119.3,114.8,113.2,103.8, 97.0, 56.0; HRMS calcd for C18H13N4O2
809; 1H NMR (300 MHz, DMSO-d6):
d 10.23 (s, 1H, NH), 8.64 (s, 1H,
[M þ H]þ 317.1039 found 317.1044.
H-2), 8.25 (dd, 1H, J1 ¼ 2.6 Hz, J2 ¼ 6.8 Hz, H-ar), 8.02 (d, 1H,
J ¼ 8.8 Hz, H-9), 7.87e7.83 (m, 1H, H-ar), 7.43 (t, 1H, J ¼ 9.2 Hz, H-
ar), 7.33 (d, 1H, J ¼ 1.6 Hz, H-6), 7.15 (dd, 1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz,
5.1.5.1.24. 7-N-[3-(Trifluoromethyl)phenyl]-7-methoxybenzofuro
[3,2-d]pyrimidin-4-amine (1y). Yield: 55%; white powder; mp 193e
194 ꢀC; IR (KBr) nmax (cmꢃ1): 1634, 1622, 1607, 1472, 1450, 1327,
1300, 1263, 1160, 1137, 1114, 1093, 1085, 1022, 830; 1H NMR
H-8), 3.93 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 162.1,
157.6, 152.7, 146.6, 145.3, 136.7, 134.2, 122.0, 121.6, 120.7, 119.0, 118.7,
116.8, 114.9, 113.1, 96.9, 56.0; HRMS calcd for C17H12N3O2FCl
[M þ H]þ 344.0602 found 344.0592.
(300 MHz, DMSO-d6): d 10.38 (s, 1H, NH), 8.68 (s, 1H, H-2), 8.42 (d,
1H, J ¼ 1.0 Hz, H-ar), 8.20 (dd, 1H, J1 ¼1.0 Hz, J2 ¼ 8.5 Hz, H-ar), 8.05
(d, 1H, J ¼ 8.8 Hz, H-9), 7.61 (td, 1H, J1 ¼ 1.0 Hz, J2 ¼ 8.5 Hz, H-ar),
7.41 (dd, 1H, J1 ¼1.0 Hz, J2 ¼ 8.5 Hz, H-ar), 7.35 (d, 1H, J ¼ 1.6 Hz, H-
5.1.5.1.19. N-(4-Chloro-2-fluorophenyl)-7-methoxybenzofuro[3,2-
d]pyrimidin-4-amine (1t). Yield: 78%; white powder; mp 243e
244 ꢀC; IR (KBr) nmax (cmꢃ1): 1618, 1588, 1484, 1471, 1430, 1415,
1332, 1307, 1290, 1262, 1134, 1118, 1078, 1021, 851, 833, 819, 807; 1H
6), 7.15 (dd, 1H, J1 ¼1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.94 (s, 3H, OCH3); 13
C
NMR (75 MHz, DMSO-d6):
d 162.2, 157.7, 152.7, 146.8, 145.3, 140.3,
134.3, 129.7, 129.1, 123.8, 122.0, 118.8, 116.3, 116.2, 114.9, 113.1, 96.9,
56.0; HRMS calcd for C18H13N3O2F3 [M þ H]þ 360.0960 found
360.0957.
NMR (300 MHz, DMSO-d6): d 9.90 (s, 1H, NH), 8.50 (s, 1H, H-2), 8.01
(d, 1H, J ¼ 8.8 Hz, H-9), 7.65 (t, 1H, J ¼ 8.6 Hz, H-ar), 7.57 (dd, 1H,
J1 ¼ 1.8 Hz, J2 ¼ 9.2 Hz, H-ar), 7.37e7.32 (m, 2H, H-ar and H-6), 7.13
(dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.92 (s, 3H, OCH3); 13C NMR
5.1.5.1.25. N1-(7-Methoxybenzofuro[3,2-d]pyrimidin-4-yl)-N4,N4-
dimethylbenzene-1,3-diamine (1z). Yield: 20%; blue powder; mp
243e244 ꢀC; IR (KBr) nmax (cmꢃ1): 1618, 1515, 1493, 1472, 1442,
1436, 1333, 1304, 1286, 1266, 1238, 1136, 1084, 1017, 968, 932, 821,
(75 MHz, DMSO-d6):
d 162.2, 157.8, 154.5, 152.9, 146.9, 146.0, 134.3,
129.6, 128.2, 125.3, 124.6, 122.0, 116.7, 114.7, 113.3, 96.9, 56.0; HRMS
calcd for C17H12N3O2FCl [M þ H]þ 344.0602 found 344.0604.
5.1.5.1.20. N-(2,4-Difluorophenyl)-7-methoxybenzofuro[3,2-d]
pyrimidin-4-amine (1u). Yield: 77%; white powder; mp 246e
247 ꢀC; IR (KBr) nmax (cmꢃ1): 1629, 1611, 1518, 1490, 1471, 1429,
1332, 1308, 1287, 1260, 1134, 1083, 1019, 960, 843, 829, 823, 809; 1H
814; 1H NMR (300 MHz, DMSO-d6):
d 9.72 (s,1H, NH), 8.49 (s,1H, H-
2), 7.99 (d, 1H, J ¼ 8.8 Hz, H-9), 7.62 (d, 2H, J ¼ 9.0 Hz, H-ar), 7.31 (d,
1H, J ¼ 1.6 Hz, H-6), 7.13 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 6.77
(d, 2H, J ¼ 9.0 Hz, H-ar), 3.93 (s, 3H, OCH3), 2.89 (s, 6H, NCH3); 13
C
NMR (75 MHz, DMSO-d6):
d 161.7, 157.3, 153.0, 147.2, 146.2, 145.6,
NMR (300 MHz, DMSO-d6):
d
9.82 (s, 1H, NH), 8.47 (s, 1H, H-2), 8.01
134.2, 128.6, 122.7 (2C), 121.8, 115.2, 112.8, 112.6 (2C), 96.9, 55.9,
40.5 (2C); HRMS calcd for C19H19N4O2 [M þ H]þ 335.1508 found
335.1501.
(d,1H, J ¼ 8.8 Hz, H-9), 7.63e7.60 (m,1H, H-ar), 7.41e7.35 (m,1H, H-
ar), 7.34 (d, 1H, J ¼ 1.6 Hz, H-6), 7.18e7.15 (m, 1H, H-ar), 7.12 (dd, 1H,
J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz,
DMSO-d6):
d
162.1, 157.7, 153.0, 146.7, 146.5, 134.2, 128.9, 128.8,
5.1.5.2. Synthesis of N-aryl-7-methoxybenzothieno[3,2-d]pyrimidin-
122.4, 122.0, 114.7, 113.2, 111.4, 104.8, 104.1, 96.8, 56.0; HRMS calcd
4-amines
(2bez). A
mixture
of
(E)-N0-(2-cyano-6-
for C17H12N3O2F2 [M þ H]þ 328.0898 found 328.0901.
methoxybenzofuran-3-yl)-N,N-dimethylformimidamide (6) (0.1 g,
0.39 mmol) and appropriate aniline (1.0 equiv) in acetic acid
(2 mL) was irradiated at 118 ꢀC (400 W). On completion (followed
by thin-layer chromatography), the reaction was cooled to room
temperature and water was added. The solid was filtered off,
washed with water and dried. The crude solid was purified by
5.1.5.1.21. N-(4-Bromo-2-fluorophenyl)-7-methoxybenzofuro[3,2-
d]pyrimidin-4-amine (1v). Yield: 67%; yellow powder; mp 240e
241 ꢀC; IR (KBr) nmax (cmꢃ1): 1618, 1584, 1513, 1481, 1470, 1430,
1408, 1391, 1334, 1306, 1291, 1262, 1236, 1191, 1135,1118, 1084, 1073,
1020, 877, 850, 833, 819, 804; 1H NMR (300 MHz, DMSO-d6):
d 9.86
(s, 1H, NH), 8.51 (s, 1H, H-2), 8.01 (d, 1H, J ¼ 8.8 Hz, H-9), 7.65 (dd,
1H, J1 ¼ 2.1 Hz, J2 ¼ 8.4 Hz, H-ar), 7.59 (d, 1H, J ¼ 8.4 Hz, H-ar), 7.45
(dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.4 Hz, H-ar), 7.35 (d, 1H, J ¼ 1.6 Hz, H-6),
7.13 (dd, 1H, J1 ¼ 1.6 Hz, J2 ¼ 8.8 Hz, H-8), 3.92 (s, 3H, OCH3); 13C
column chromatography over silica gel using a gradient of
petroleum ether/ethyl acetate (100:0 to 0:100, v/v) as the eluent
to give the desired compounds (2bez).
5.1.5.2.1. 7-Methoxy-N-phenyl-benzothieno[3,2-d]pyrimidin-4-
amine (2b). Yield: 67%; white powder; mp 231e232 ꢀC; IR (KBr)
nmax (cmꢃ1): 1597, 1562, 1531, 1503, 1496, 1485, 1455, 1439, 1263,
1252, 1229, 1046, 1023, 832, 827, 820; 1H NMR (300 MHz, DMSO-
NMR (75 MHz, DMSO-d6):
d 162.2, 157.8, 152.9, 147.0, 145.9, 134.4,
128.4, 127.4, 125.8, 122.0, 119.4, 119.1, 117.2, 114.7, 113.2, 96.9, 56.0;
HRMS calcd for C17H12N3O2FBr [M þ H]þ 388.0097 found 388.0085.
5.1.5.1.22. N-(2-Fluoro-4-methoxyphenyl)-7-methoxybenzofuro
[3,2-d]pyrimidin-4-amine (1w). Yield: 80%; white powder; mp
195e196 ꢀC; IR (KBr) nmax (cmꢃ1): 1634, 1622, 1592, 1524, 1490,
1467, 1428, 1299, 1279, 1260, 1239, 1200, 1135, 1104, 1086, 1026,
d6):
d
9.65 (s, 1H, NH), 8.67 (s, 1H, H-2), 8.23 (d, 1H, J ¼ 8.7 Hz, H-9),
7.77 (m, 3H, H-6 and H-ar), 7.39 (dt, 2H, J1 ¼ 1.0 Hz, J2 ¼ 8.0 Hz, H-
ar), 7.19 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 7.14 (dt, 1H, J1 ¼1.0 Hz,
J2 ¼ 8.4 Hz, H-ar), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
829, 824, 813; 1H NMR (300 MHz, DMSO-d6):
d
9.62 (s, 1H, NH),
d 161.0, 156.2, 155.0, 154.3, 141.9, 139.0, 128.5 (2C), 126.9, 123.9,
8.43 (s, 1H, H-2), 7.99 (d, 1H, J ¼ 8.8 Hz, H-9), 7.42 (t, 1H, J ¼ 9.0 Hz,
H-ar), 7.32 (d, 1H, J ¼ 1.6 Hz, H-6), 7.11 (dd, 1H, J1 ¼ 1.6 Hz,
J2 ¼ 8.8 Hz, H-8), 6.95 (dd, 1H, J1 ¼ 2.6 Hz, J2 ¼ 9.0 Hz, H-ar), 6.82
(dd, 1H, J1 ¼ 2.6 Hz, J2 ¼ 9.0 Hz, H-ar), 3.91 (s, 3H, OCH3), 3.80 (s, 3H,
123.6, 122.3 (2C), 115.1, 113.6, 106.1, 55.8; HRMS calcd for
C
17H14N3OS [M þ H]þ 308.0858 found 308.0851.
5.1.5.2.2. 7-Methoxy-N-(p-tolyl)benzothieno[3,2-d]pyrimidin-4-
amine (2c). Yield: 80%; white powder; mp 224e225 ꢀC; IR (KBr)
nmax (cmꢃ1): 1597, 1562, 1533, 1505, 1485, 1453, 1438, 1429, 1402,
1263, 1249, 1228, 1045, 1022, 820, 813; 1H NMR (300 MHz, DMSO-
OCH3); 13C NMR (75 MHz, DMSO-d6):
d 162.0, 159.4, 157.6, 153.1,
147.0, 146.4, 134.2, 128.8, 127.8, 121.9, 118.3, 114.8, 113.1, 109.9, 102.2,
96.8, 56.0, 55.7; HRMS calcd for C18H15N3O3F [M þ H]þ 340.1097
found 340.1082.
d6):
d
9.59 (s, 1H, NH), 8.64 (s, 1H, H-2), 8.20 (d, 1H, J ¼ 8.7 Hz, H-9),
7.76 (d, 1H, J ¼ 2.1 Hz, H-6), 7.62 (d, 2H, J ¼ 8.3 Hz, H-ar), 7.19

292
Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
(dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 7.18 (d, 2H, J ¼ 8.3 Hz, H-ar),
3.91 (s, 3H, OCH3), 2.32 (s, 3H, CH3); 13C NMR (75 MHz, DMSO-d6):
249 ꢀC; IR (KBr) nmax (cmꢃ1): 1583, 1532, 1499, 1479, 1454, 1440,
1329, 1264, 1242, 1228, 1183, 1039, 1016, 921, 857, 833, 802; 1H NMR
d
160.9, 156.0, 155.1, 154.4, 141.9, 136.2, 132.9, 128.9 (2C), 126.9,
(300 MHz, DMSO-d6): d 9.55 (s, 1H, NH), 8.63 (s, 1H, H-2), 8.20 (d,
123.8, 122.7 (2C), 115.1, 113.3, 106.1, 55.7, 20.5; HRMS calcd for
C
1H, J ¼ 8.7 Hz, H-9), 7.75 (d, 1H, J ¼ 2.1 Hz, H-6), 7.36 (d, 1H,
J ¼ 1.8 Hz, H-ar), 7.19 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 7.14 (dd,
1H, J1 ¼1.8 Hz, J2 ¼ 8.3 Hz, H-ar), 6.94 (d, 1H, J ¼ 8.3 Hz, H-ar), 6.06
(s, 2H, CH2), 3.91 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
18H16N3OS [M þ H]þ 322.1014 found 322.1012.
5.1.5.2.3. 7-Methoxy-N-(m-tolyl)benzothieno[3,2-d]pyrimidin-4-
amine (2d). Yield: 64%; white powder; mp 232e233 ꢀC; IR (KBr)
nmax (cmꢃ1): 1596, 1571, 1530, 1508, 1486, 1455, 1439, 1264, 1251,
d
160.9, 156.1, 155.4, 154.4, 147.0, 143.9, 141.9, 132.7, 126.9, 123.8,
1230, 1046, 1024, 832, 818; 1H NMR (300 MHz, DMSO-d6):
d
9.59
116.4, 115.0, 113.1, 107.8, 106.0, 105.4, 101.1, 55.7; HRMS calcd for
(s, 1H, NH), 8.67 (s, 1H, H-2), 8.22 (d, 1H, J ¼ 8.7 Hz, H-9), 7.77 (d,
1H, J ¼ 2.1 Hz, H-6), 7.58 (m, 2H, H-ar), 7.27 (td, 1H, J1 ¼ 1.0 Hz,
J2 ¼ 8.0 Hz, H-ar), 7.19 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 6.96
(d, 1H, J ¼ 8.0 Hz, H-ar), 3.92 (s, 3H, OCH3), 2.34 (s, 3H, CH3); 13C
C
18H14N3O3S [M þ H]þ 352.0756 found 352.0746.
5.1.5.2.9. N-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-7-
methoxybenzothieno[3,2-d]pyrimidin-4-amine (2j). Yield: 74%;
purple powder; mp 219e220 ꢀC; IR (KBr) nmax (cmꢃ1): 1599, 1568,
1496, 1451, 1431, 1416, 1309, 1268, 1238, 1228, 1203, 1166, 1068,
1060, 1044, 1023, 880, 862, 817; 1H NMR (300 MHz, DMSO-d6):
NMR (75 MHz, DMSO-d6):
d 161.0, 156.2, 155.1, 154.4, 141.9, 138.8,
137.7, 128.3, 126.9, 124.4, 123.8, 122.9, 119.6, 115.1, 113.6, 106.1, 55.8,
21.2; HRMS calcd for C18H16N3OS [M þ H]þ 322.1014 found
322.1009.
d
9.48 (s, 1H, NH), 8.63 (s, 1H, H-2), 8.20 (d, 1H, J ¼ 8.7 Hz, H-9), 7.75
(d, 1H, J ¼ 2.1 Hz, H-6), 7.32 (d, 1H, J ¼ 2.3 Hz, H-ar), 7.19 (dd, 1H,
J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 7.16 (dd, 1H, J1 ¼ 2.3 Hz, J2 ¼ 8.7 Hz, H-
ar), 6.86 (d, 1H, J ¼ 8.7 Hz, H-ar), 4.27 (br s, 4H, CH2), 3.91 (s, 3H,
5.1.5.2.4. 7-Methoxy-N-(4-methoxyphenyl)benzothieno[3,2-d]
pyrimidin-4-amine (2e). Yield: 55%; purple powder; mp 240e
241 ꢀC; IR (KBr) nmax (cmꢃ1): 1600, 1570, 1506, 1480, 1446, 1431,
1410, 1245, 1230, 1176, 1140, 1105, 1045, 1034, 1023, 953, 878, 822;
OCH3); 13C NMR (75 MHz, DMSO-d6):
d 160.9, 156.0, 155.2, 154.4,
142.8, 141.9, 140.1, 132.2, 126.9, 123.8, 116.5, 116.2, 115.0, 113.1, 112.1,
106.1, 64.1, 64.0, 55.7; HRMS calcd for C19H16N3O3S [M þ H]þ
366.0912 found 366.0906.
5.1.5.2.10. N-(4-Fluorophenyl)-7-methoxybenzothieno[3,2-d]pyr-
imidin-4-amine (2k). Yield: 73%; white powder; mp 248e249 ꢀC;
IR (KBr) nmax (cmꢃ1): 1571, 1504, 1486, 1451, 1440, 1430, 1402,
1264, 1228, 1210, 1183, 1157, 1043, 1021, 826; 1H NMR (300 MHz,
1H NMR (300 MHz, DMSO-d6):
d 9.52 (s, 1H, NH), 8.59 (s, 1H, H-2),
8.19 (d, 1H, J ¼ 8.7 Hz, H-9), 7.74 (d, 1H, J ¼ 2.1 Hz, H-6), 7.57 (d, 2H,
J ¼ 8.8 Hz, H-ar), 7.16 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 6.96 (d,
2H, J ¼ 8.8 Hz, H-ar), 3.90 (s, 3H, OCH3), 3.78 (s, 3H, OCH3); 13C NMR
(75 MHz, DMSO-d6):
d 160.9, 156.2, 156.0, 155.5, 154.5, 141.9, 131.4,
126.9, 125.1 (2C), 123.8, 115.0, 113.7 (2C), 112.9, 106.0, 55.7, 55.2;
HRMS calcd for C18H16N3O2S [M þ H]þ 338.0963 found 338.0961.
5.1.5.2.5. 7-Methoxy-N-(3,4-dimethoxyphenyl)benzothieno[3,2-
d]pyrimidin-4-amine (2f). Yield: 92%; purple powder; mp 218e
219 ꢀC; IR (KBr) nmax (cmꢃ1): 1602, 1566, 1505, 1452, 1440, 1429,
1409, 1260, 1239, 1226, 1218, 1164, 1128, 1044, 1024, 1016, 975, 858,
DMSO-d6):
d 9.68 (s, 1H, NH), 8.66 (s, 1H, H-2), 8.22 (d, 1H,
J ¼ 8.7 Hz, H-9), 7.80e7.75 (m, 3H, H6 and H-ar), 7.26e7.17 (m, 3H,
H-8 and H-ar), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d
161.0, 156.9, 156.2, 155.0, 154.3, 141.9, 135.2 (2C), 126.9, 124.4,
123.9, 115.2, 115.1, 114.9, 113.4, 106.1, 55.8; HRMS calcd for
836; 1H NMR (300 MHz, DMSO-d6):
d
9.52 (s, 1H, NH), 8.62 (s, 1H,
C
17H13N3O2FS [M þ H]þ 326.0763 found 326.0755.
H-2), 8.19 (d, 1H, J ¼ 8.7 Hz, H-9), 7.74 (d, 1H, J ¼ 2.1 Hz, H-6), 7.28
(m, 2H, H-ar), 7.15 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 6.97 (d, 1H,
J ¼ 8.3 Hz, H-ar), 3.90 (s, 3H, OCH3), 3.78 (s, 3H, OCH3), 3.77 (s, 3H,
5.1.5.2.11. N-(4-Bromophenyl)-7-methoxybenzothieno[3,2-d]pyr-
imidin-4-amine (2l). Yield: 54%; white powder; mp 272e273 ꢀC; IR
(KBr) nmax (cmꢃ1): 1599, 1559, 1527, 1500, 1481, 1452, 1438, 1392,
1343, 1263, 1250, 1228, 1063, 1044, 1018, 1010, 834, 826, 815; 1H
OCH3); 13C NMR (75 MHz, DMSO-d6):
d 160.9, 156.1, 155.5, 154.4,
148.4, 145.8, 142.0, 131.8, 126.9, 123.8, 115.7, 115.0, 112.9, 111.6, 108.5,
106.0, 55.7 (2C), 55.5; HRMS calcd for C19H18N3O3S [M þ H]þ
368.1069 found 368.1061.
5.1.5.2.6. 7-Methoxy-N-(3,5-dimethoxyphenyl)benzothieno[3,2-
d]pyrimidin-4-amine (2g). Yield: 83%; grey powder; mp 201e
202 ꢀC; IR (KBr) nmax (cmꢃ1): 1607, 1577, 1532, 1455, 1446, 1435,
1421, 1277, 1226, 1205, 1168, 1151, 1141, 1058, 838, 819; 1H NMR
NMR (300 MHz, DMSO-d6): d 9.75 (s, 1H, NH), 8.70 (s, 1H, H-2), 8.22
(d, 1H, J ¼ 8.7 Hz, H-9), 7.82 (d, 2H, J ¼ 7.8 Hz, H-ar), 7.79 (d, 1H,
J ¼ 2.1 Hz, H-6), 7.55 (d, 2H, J ¼ 7.8 Hz, H-ar), 7.19 (dd,1H, J1 ¼ 2.1 Hz,
J2 ¼ 8.7 Hz, H-8), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d
161.1, 156.3, 154.6, 154.2, 141.9, 138.6, 131.2 (2C), 126.8, 123.9, 123.7
(2C), 115.2, 115.0, 114.0, 106.2, 55.8; HRMS calcd for C17H13N3OSBr
[M þ H]þ 385.9963 found 385.9955.
(300 MHz, DMSO-d6):
d
9.57 (s, 1H, NH), 8.72 (s, 1H, H-2), 8.22 (d,
5.1.5.2.12. N-(4-Chlorophenyl)-7-methoxybenzothieno[3,2-d]pyr-
imidin-4-amine (2m). Yield: 59%; white powder; mp 261e262 ꢀC;
IR (KBr) nmax (cmꢃ1): 1599, 1560, 1528, 1499, 1483, 1452, 1441,
1428,1396,1343,1264,1250,1229,1173,1093,1062,1044,1015, 826,
1H, J ¼ 8.7 Hz, H-9), 7.79 (d, 1H, J ¼ 2.1 Hz, H-6), 7.20 (dd, 1H,
J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 7.12 (d, 2H, J ¼ 2.0 Hz, H-ar), 6.29 (t,1H,
J ¼ 2.0 Hz, H-ar), 3.92 (s, 3H, OCH3), 3.77 (s, 6H, OCH3); 13C NMR
(75 MHz, DMSO-d6):
d
161.0, 160.3 (2C), 156.2, 154.9, 154.2, 141.9,
817; 1H NMR (300 MHz, DMSO-d6):
d 9.76 (s,1H, NH), 8.70 (s, 1H, H-
140.8, 126.9, 123.9, 115.1, 113.9, 106.1, 100.2 (2C), 95.4, 55.8, 55.1
(2C); HRMS calcd for C19H18N3O3S [M þ H]þ 368.1069 found
368.1073.
5.1.5.2.7. 7-Methoxy-N-(3,4,5-trimethoxyphenyl)benzothieno
[3,2-d]pyrimidin-4-amine (2h). Yield: 84%; grey powder; mp 230e
231 ꢀC; IR (KBr) nmax (cmꢃ1): 1602, 1578, 1505, 1489, 1456, 1444,
1429, 1408, 1228, 1125, 1051, 1041, 1029, 1001, 827; 1H NMR
2), 8.22 (d, 1H, J ¼ 8.7 Hz, H-9), 7.85 (d, 2H, J ¼ 8.7 Hz, H-ar), 7.79 (d,
1H, J ¼ 2.1 Hz, H-6), 7.43 (d, 2H, J ¼ 8.7 Hz, H-ar), 7.19 (dd, 1H,
J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz,
DMSO-d6): d 161.1, 156.3, 154.7, 154.2, 141.9, 138.1, 128.3 (2C), 127.0,
126.9, 123.9, 123.4 (2C), 115.2, 113.9, 106.2, 55.8; HRMS calcd for
C
17H13N3OSCl [M þ H]þ 342.0468 found 342.0456.
5.1.5.2.13. N-(3-Chlorophenyl)-7-methoxybenzothieno[3,2-d]pyr-
(300 MHz, DMSO-d6):
d
9.57 (s, 1H, NH), 8.68 (s, 1H, H-2), 8.21 (d,
imidin-4-amine (2n). Yield: 61%; white powder; mp 278e279 ꢀC;
IR (KBr) nmax (cmꢃ1): 1594, 1559, 1529, 1501, 1483, 1475, 1451,
1435, 1415, 1270, 1257, 1249, 1228, 1061, 1044, 1019, 870, 833; 1H
1H, J ¼ 8.7 Hz, H-8), 7.77 (d, 1H, J ¼ 2.1 Hz, H-6), 7.20 (s, 2H, H-ar),
7.19 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-9), 3.92 (s, 3H, OCH3), 3.80 (s,
6H, OCH3), 3.68 (s, 3H; OCH3); 13C NMR (75 MHz, DMSO-d6):
NMR (300 MHz, DMSO-d6): d 9.80 (s, 1H, NH), 8.75 (s, 1H, H-2), 8.23
d
161.0, 156.1,155.1,154.3,152.5 (2C),141.9,134.9,134.0,126.9,123.8,
(d,1H, J ¼ 8.7 Hz, H-8), 8.06 (s,1H, H-ar), 7.80 (d,1H, J ¼ 2.1 Hz, H-6),
7.77 (d, 1H, J ¼ 8.1 Hz, H-ar), 7.40 (dt, 1H, J1 ¼ 8.1 Hz, J2 ¼ 9.0 Hz, H-
ar), 7.19 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-9), 7.15 (d, 1H, J ¼ 9.0 Hz,
115.1, 113.4, 106.1, 100.5 (2C), 60.1, 55.8 (3C); HRMS calcd for
C
20H20N3O4S [M þ H]þ 398.1175 found 398.1169.
5.1.5.2.8. N-(Benzo[d][1,3]dioxol-5-yl)-7-methoxybenzothieno
H-ar), 3.94 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 161.1,
[3,2-d]pyrimidin-4-amine (2i). Yield: 84%; grey powder; mp 248e
156.4, 154.6, 154.2, 142.0, 140.8, 132.8, 130.1, 126.8, 123.9, 122.8,

Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
293
120.9, 119.9, 115.2, 114.1, 106.2, 55.8; HRMS calcd for C17H13N3OSCl
[M þ H]þ 342.0468 found 342.0462.
H-2), 8.21 (d, 1H, J ¼ 8.7 Hz, H-9), 7.77 (d, 1H, J ¼ 2.0 Hz, H-6),
7.62e7.52 (m, 2H, H-ar), 7.35 (dd, 1H, J1 ¼ 1.0 Hz, J2 ¼ 8.5 Hz, H-
ar), 7.18 (dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 8.7 Hz, H-8), 3.90 (s, 3H, OCH3);
5.1.5.2.14. N-(2-Chlorophenyl)-7-methoxybenzothieno[3,2-d]pyr-
imidin-4-amine (2o). Yield: 68%; white powder; mp 202e203 ꢀC;
IR (KBr) nmax (cmꢃ1): 1678, 1598, 1565, 1531, 1519, 1454, 1442,
1434, 1421, 1343, 1267, 1252, 1240, 1224, 1052, 1043, 1028; 1H NMR
13C NMR (75 MHz, DMSO-d6):
d 162.2, 157.8, 154.5, 152.9, 146.9,
146.0, 134.3, 129.6, 128.2, 125.3, 124.6, 122.0, 116.7, 114.7, 113.3,
96.9, 56.0; HRMS calcd for C17H12N3OFSCl [M þ H]þ 360.0374
found 360.0371.
(300 MHz, DMSO-d6):
d 9.68 (s, 1H, NH), 8.57 (s, 1H, H-2), 8.21
(d, 1H, J ¼ 8.7 Hz, H-9), 7.75 (d, 1H, J ¼ 2.1 Hz, H-6), 7.62e7.59 (m,
2H, H-ar), 7.44e7.39 (m, 2H, H-ar), 7.20 (dd, 1H, J1 ¼ 2.1 Hz,
J2 ¼ 8.7 Hz, H-8), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.2.20. N-(2,4-Difluorophenyl)-7-methoxybenzothieno[3,2-d]
pyrimidin-4-amine (2u). Yield: 73%; white powder; mp 211e
212 ꢀC; IR (KBr) nmax (cmꢃ1): 1602, 1579, 1505, 1485, 1450, 1437,
1425, 1263, 1237, 1136, 1062, 1045, 1025, 969, 950, 836; 1H NMR
d
161.0, 156.6, 154.6, 142.1, 135.2, 131.8, 130.3, 129.7, 128.3, 127.7,
126.7, 124.1, 115.6, 115.0, 112.6, 106.1, 55.7; HRMS calcd for
C
(300 MHz, DMSO-d6): d 9.63 (s, 1H, NH), 8.56 (s, 1H, H-2), 8.21
17H13N3OSCl [M þ H]þ 342.0468 found 342.0453.
(d,1H, J ¼ 8.8 Hz, H-9), 7.74 (d,1H, J ¼ 2.1 Hz, H-6), 7.59e7.55 (m,1H,
H-ar), 7.41e7.37 (m, 1H, H-ar), 7.18 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.8 Hz,
H-8), 7.17e7.14 (m, 1H, H-ar), 3.89 (s, 3H, OCH3); 13C NMR (75 MHz,
5.1.5.2.15. N-(3,4-Dichlorophenyl)-7-methoxybenzothieno[3,2-d]
pyrimidin-4-amine (2p). Yield: 69%; white powder; mp 232e
233 ꢀC; IR (KBr) nmax (cmꢃ1): 1721, 1606, 1591, 1561, 1537, 1504,
1475, 1452, 1436, 1396, 1345, 1273, 1246, 1227, 1068, 1055, 1026,
DMSO-d6):
d 161.0, 156.3, 155.9, 154.6, 142.0, 130.2, 130.1, 126.7,
123.9, 122.3, 115.1, 112.8, 111.5, 106.2, 104.9, 104.2, 55.7; HRMS calcd
868, 854, 818; 1H NMR (300 MHz, DMSO-d6):
d 9.87 (s,1H, NH), 8.76
for C17H12N3OF2S[M þ H]þ 344.0669 found 344.0672.
(s, 1H, H-2), 8.28 (d, 1H, J ¼ 2.0 Hz, H-ar), 8.22 (d, 1H, J ¼ 8.7 Hz, H-
9), 7.85 (dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 9.0 Hz, H-ar), 7.80 (d, 1H, J ¼ 2.1 Hz,
H-6), 7.62 (d, 1H, J ¼ 9.0 Hz, H-ar), 7.20 (dd, 1H, J1 ¼ 2.1 Hz,
J2 ¼ 8.7 Hz, H-8), 3.92 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.2.21. N-(4-Bromo-2-fluorophenyl)-7-methoxybenzothieno
[3,2-d]pyrimidin-4-amine (2v). Yield: 75%; yellow powder; mp
243e244 ꢀC; IR (KBr) nmax (cmꢃ1): 1595, 1566, 1519, 1502, 1474,
1465,1435,1425,1403,1289,1261,1252,1234,1190,1045,1022, 882,
d
161.2, 156.4, 154.3, 154.1, 142.0, 139.6, 130.6, 130.3, 126.8, 124.4,
875, 832, 815; 1H NMR (300 MHz, DMSO-d6):
d 9.68 (s, 1H, NH),
124.0, 122.4, 121.2, 115.2, 114.3, 106.2, 55.8; HRMS calcd for
C
8.59 (s, 1H, H-2), 8.21 (d, 1H, J ¼ 8.7 Hz, H-9), 7.77 (d, 1H, J ¼ 2.0 Hz,
H-6), 7.68 (dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 10.1 Hz, H-ar), 7.54e7.46 (m, 2H,
H-ar), 7.18 (dd, 1H, J1 ¼ 2.0 Hz, J2 ¼ 8.7 Hz, H-8), 3.91 (s, 3H, OCH3);
17H12N3OSCl2 [M þ H]þ 376.0078 found 376.0073.
5.1.5.2.16. N-(3,5-Dichlorophenyl)-7-methoxybenzothieno[3,2-d]
pyrimidin-4-amine (2q). Yield: 50%; white powder; mp 264e
265 ꢀC; IR (KBr) nmax (cmꢃ1): 1589, 1561, 1524, 1502, 1443, 1431,
1403, 1268, 1252, 1230, 1045, 1023, 979, 854, 845, 833, 807; 1H NMR
13C NMR (75 MHz, DMSO-d6):
d 161.1, 156.5, 155.6, 155.2, 154.5,
142.3,130.0,127.6,126.7,125.5,123.9,119.8,119.3,115.3,113.4,106.3,
55.9; HRMS calcd for C17H12N3OFSBr [M þ H]þ 405.9840 found
405.9832.
(300 MHz, DMSO-d6):
d 9.88 (s, 1H, NH), 8.81 (s, 1H, H-2), 8.23
(d, 1H, J ¼ 8.7 Hz, H-9), 8.07 (d, 2H, J ¼ 1.9 Hz, H-ar), 7.81 (d, 1H,
J ¼ 2.1 Hz, H-6), 7.28 (t, 1H, J ¼ 1.9 Hz, H-ar), 7.21 (dd, 1H, J1 ¼ 2.1 Hz,
J2 ¼ 8.7 Hz, H-8), 3.93 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.2.22. N-(2-Fluoro-4-methoxyphenyl)-7-methoxybenzothieno
[3,2-d]pyrimidin-4-amine (2w). Yield: 72%; white powder; mp 249e
250 ꢀC; IR (KBr) nmax (cmꢃ1): 1600,1574,1508,1486,1453,1441,1425,
1264, 1238,1225,1194, 1155, 1045, 1033,1023, 946, 844, 832, 823; 1H
d
161.2, 156.6, 154.2, 154.0, 142.0, 141.9, 133.7 (2C), 126.7, 124.0,
121.9, 118.9 (2C), 115.3, 114.5, 106.2, 55.8; HRMS calcd for
C
NMR (300 MHz, DMSO-d6): d 9.44 (s, 1H, NH), 8.54 (s, 1H, H-2), 8.18
17H12N3OSCl2 [M þ H]þ 376.0078 found 376.0083.
(d, 1H, J ¼ 8.7 Hz, H-9), 7.72 (d, 1H, J ¼ 2.1 Hz, H-6), 7.42 (t, 1H,
J ¼ 9.2 Hz, H-ar), 7.16 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 6.96 (dd,
1H, J1 ¼1.2 Hz, J2 ¼ 9.0 Hz, H-ar), 6.85 (dd,1H, J1 ¼1.2 Hz, J2 ¼ 9.0 Hz,
H-ar), 3.88 (s, 3H, OCH3), 3.82 (s, 3H, OCH3); 13C NMR (75 MHz,
5.1.5.2.17. N-(2,4-Dichlorophenyl)-7-methoxybenzothieno[3,2-d]
pyrimidin-4-amine (2r). Yield: 77%; yellow powder; mp 238e
239 ꢀC; IR (KBr) nmax (cmꢃ1): 1600, 1588, 1558, 1529, 1508, 1455,
1448, 1426, 1279, 1260, 1250, 1232, 1225, 1040, 1012, 839, 827, 822;
DMSO-d6): d 160.9, 159.1, 156.5, 156.2, 154.6, 142.1, 130.4, 126.6, 123.9,
1H NMR (300 MHz, DMSO-d6):
d
9.72 (s, 1H, NH), 8.57 (s, 1H, H-2),
117.9,115.0,112.3,110.1, 106.0,102.2, 101.9, 55.8, 55.7; HRMS calcd for
8.20 (d, 1H, J ¼ 8.7 Hz, H-9), 7.78 (d, 1H, J ¼ 2.1 Hz, H-6), 7.75 (d, 1H,
J ¼ 2.8 Hz, H-ar), 7.61 (d, 1H, J ¼ 8.1 Hz, H-ar), 7.52 (dd, 1H,
J1 ¼ 2.8 Hz, J2 ¼ 8.1 Hz, H-ar), 7.18 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-
C
18H15N3O2FS [M þ H]þ 356.0869 found 356.0864.
5.1.5.2.23. 4-[(7-Methoxybenzothieno[3,2-d]pyrimidin-4-yl)
amino]benzonitrile (2x). Yield: 67%; white powder; mp 262e
263 ꢀC; IR (KBr) nmax (cmꢃ1): 2217 (CN), 1597, 1555, 1529, 1503,
1448, 1424, 1406, 1371, 1341, 1263, 1226, 1173, 1043, 1014, 955, 841,
8), 3.89 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 161.0, 156.5,
155.9, 154.5, 142.1, 134.6, 132.6, 131.5, 131.2, 129.2, 127.8, 126.6,
123.9, 115.1, 112.8, 106.1, 55.7; HRMS calcd for C17H12N3OSCl2
[M þ H]þ 376.0078 found 376.0087.
827, 820; 1H NMR (300 MHz, DMSO-d6):
d 10.06 (s, 1H, NH), 8.80
(s,1H, H-2), 8.25 (d,1H, J ¼ 8.7 Hz, H-9), 8.11 (d, 2H, J ¼ 8.6 Hz, H-ar),
7.83e7.81 (m, 3H, H-6 and H-ar), 7.21 (dd, 1H, J1 ¼ 2.1 Hz,
J2 ¼ 8.7 Hz, H-8), 3.93 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
5.1.5.2.18. N-(3-Chloro-4-fluorophenyl)-7-methoxybenzothieno
[3,2-d]pyrimidin-4-amine (2s). Yield: 66%; white powder; mp 252e
253 ꢀC; IR (KBr) nmax (cmꢃ1): 1600, 1566, 1530, 1496, 1483, 1450,
1439, 1430, 1389, 1342, 1267, 1231, 1211, 1062, 1043, 1018, 870, 835,
d
161.3, 156.8,154.2,154.0,143.9,142.1,132.9 (2C),126.7,124.0,120.8
(2C), 119.3, 115.3, 114.9, 106.2, 104.2, 55.8; HRMS calcd for
827, 815; 1H NMR (300 MHz, DMSO-d6):
d
9.79 (s, 1H, NH), 8.73 (s,
C
18H13N4OS [M þ H]þ 333.0810 found 333.0806.
1H, H-2), 8.23 (d, 1H, J ¼ 8.7 Hz, H-9), 8.16 (dd, 1H, J1 ¼ 2.2 Hz,
J2 ¼ 6.6 Hz, H-ar), 7.79e7e76 (m, 2H, H-6 and H-ar), 7.44 (t, 1H,
J ¼ 9.2 Hz, H-ar), 7.19 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 3.92 (s,
5.1.5.2.24. N-[3-(Trifluoromethyl)phenyl]-7-methoxybenzothieno
[3,2-d]pyrimidin-4-amine (2y). Yield: 62%; white powder; mp
236e237 ꢀC; IR (KBr) nmax (cmꢃ1): 1578, 1530, 1451, 1439, 1325,
1262, 1231, 1217, 1167, 1137, 1109, 1101, 1060, 1044, 1022, 833; 1H
3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 161.1, 156.3,154.6,154.2,
141.9, 136.5, 126.8, 123.9, 123.2, 122.1, 118.9, 116.7, 116.4, 115.2, 113.8,
106.2, 55.8; HRMS calcd for C17H12N3OFSCl [M þ H]þ 360.0374
found 360.0388.
NMR (300 MHz, DMSO-d6): d 9.93 (s, 1H, NH), 8.77 (s, 1H, H-2),
8.29e8.19 (m, 3H, H-9 and H-ar), 7.83 (d, 1H, J ¼ 1.7 Hz, H-6), 7.63
(td, 1H, J1 ¼ 1.0 Hz, J2 ¼ 7.8 Hz, H-ar), 7.44 (dd, 1H, J1 ¼ 1.0 Hz,
J2 ¼ 7.8 Hz, H-ar), 7.22 (dd, 1H, J1 ¼1.7 Hz, J2 ¼ 8.6 Hz, H-8), 3.94 (s,
5.1.5.2.19. N-(4-Chloro-2-fluorophenyl)-7-methoxybenzothieno
[3,2-d]pyrimidin-4-amine (2t). Yield: 73%; white powder; mp
226e227 ꢀC; IR (KBr) nmax (cmꢃ1): 1618, 1588, 1484, 1471, 1430,
1415, 1332, 1307, 1290, 1262, 1134, 1118, 1078, 1021, 851, 833, 819,
3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
d 161.7, 161.2, 156.5, 154.6,
154.2, 142.0, 140.2, 129.7, 129.4, 126.8, 124.9, 124.0, 117.4, 115.3,
114.2, 106.2, 95.7, 55.8; HRMS calcd for C18H13N3OF3S [M þ H]þ
376.0731 found 376.0727.
807; 1H NMR (300 MHz, DMSO-d6):
d 9.71 (s, 1H, NH), 8.59 (s, 1H,

294
Y. Loidreau et al. / European Journal of Medicinal Chemistry 59 (2013) 283e295
5.1.5.2.25. N1-(7-Methoxybenzothieno[3,2-d]pyrimidin-4-yl)-
Acknowledgements
N4,N4-dimethylbenzene-1,3-diamine (2z). Yield: 16%; blue powder;
mp 233e234 ꢀC; IR (KBr) nmax (cmꢃ1): 1605, 1557, 1524, 1478, 1459,
1426, 1366, 1267, 1224, 1182, 1055, 1032, 853, 811; 1H NMR
This work was supported by a PhD grant from the Région Haute-
Normandie (YL) and the ISCE-CHEM program. TB acknowledges
Milestone S.r.l. (Italy) for providing the microwave reactors, finan-
cial and technical support. This research was supported by grants
from the “Fonds Unique Interministériel” (FUI) PHARMASEA
project (LM), the “Association France-Alzheimer (Finistère)” (LM)
and “CRITT-Santé Bretagne” (LM).
(300 MHz, DMSO-d6):
d 9.38 (s, 1H, NH), 8.56 (s, 1H, H-2), 8.18
(d, 1H, J ¼ 8.7 Hz, H-9), 7.69 (d, 1H, J ¼ 2.1 Hz, H-6), 7.41 (d, 2H,
J ¼ 8.9 Hz, H-ar), 7.15 (dd, 1H, J1 ¼ 2.1 Hz, J2 ¼ 8.7 Hz, H-8), 6.77
(d, 2H, J ¼ 8.9 Hz, H-ar), 3.89 (s, 3H, OCH3), 2.93 (s, 6H, NCH3); 13
C
NMR (75 MHz, DMSO-d6):
d 160.7 (2C), 155.9, 154.5, 148.2, 142.1,
127.1, 126.8, 125.8, 123.8 (2C), 114.9, 112.4, 112.2 (2C), 105.9, 55.7,
40.3 (2C); HRMS calcd for C19H19N4OS [M þ H]þ 351.1280 found
351.1274.
Appendix A. Supplementary data
Supplementary data related to this article can be found at
http://dx.doi.org/10.1016/j.ejmech.2012.11.030.
5.2. In vitro kinase preparation and assays [17]
5.2.1. Buffers
References
Buffer A: MgCl2 (10 mM),
aminoethylether)-N,N,N0,N0-tetraacetic acid (EGTA), 1 mM dithio-
threitol (DTT), 25 mM TriseHCl pH 7.5, 50 g heparin/mL.
Buffer B: -Glycerophosphate (60 mM), 30 mM p-nitro-
1 mM ethylene glycol-bis(2-
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[
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