Design and synthesis of 3-(3-((9 H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-phenylquinazolin-4(3 H)-one derivatives to induce ACE inhibitory activity

Article abstract of DOI:10.1016/j.ejmech.2015.04.009

In an attempt to develop a new class of cardiovascular drugs, a series of novel carbazolyloxy phenylquinazoline derivatives 9a-g have been synthesized and evaluated as angiotensin converting enzyme (ACE) inhibitors. Most of these compounds exhibited activity as significant ACE inhibitors and three compounds (9b, 9c & 9e) showed maximum inhibitory potency in enzyme based assays. To render support to the experimental results, a series of quinazolinone derivatives were docked into active site of ACE and identified the probable binding modes compared to Lisinopril. Also we have identified common pharmacophore hypothesis (AAADDRR) among the best docked conformers of most potent compounds in a series of compounds. The most potent 9b, 9c, 9e compounds shared common active site with the Lisinopril binding site and retained the key active site residue interactions. The obtained results from pharmacological and molecular modeling studies can be utilized for further optimization of identified hits for selective inhibition of ACE.

Full text of DOI:10.1016/j.ejmech.2015.04.009

European Journal of Medicinal Chemistry 96 (2015) 22e29
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Design and synthesis of 3-(3-((9H-carbazol-4-yl)oxy)-2-
hydroxypropyl)-2-phenylquinazolin-4(3H)-one derivatives to induce
ACE inhibitory activity
a
a
a
c
Ramineni Venkatesh , Suresh Kasaboina , Hanmant K. Gaikwad , Sridhara Janardhan ,
a
a,
*
c
b
Rajashaker Bantu , Lingaiah Nagarapu , G. Narahari Sastry , Sanjay K. Banerjee
Organic Chemistry Division II (CPC), CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
Pharmacology Division, Indian Institute of Chemical Technology, Hyderabad 500007, India
Centre for Molecular Modeling, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
a
b
c
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 12 November 2014
Received in revised form
In an attempt to develop a new class of cardiovascular drugs, a series of novel carbazolyloxy phenyl-
quinazoline derivatives 9aeg have been synthesized and evaluated as angiotensin converting enzyme
(
ACE) inhibitors. Most of these compounds exhibited activity as significant ACE inhibitors and three
31 March 2015
compounds (9b, 9c & 9e) showed maximum inhibitory potency in enzyme based assays. To render
support to the experimental results, a series of quinazolinone derivatives were docked into active site of
ACE and identified the probable binding modes compared to Lisinopril. Also we have identified common
pharmacophore hypothesis (AAADDRR) among the best docked conformers of most potent compounds
in a series of compounds. The most potent 9b, 9c, 9e compounds shared common active site with the
Lisinopril binding site and retained the key active site residue interactions. The obtained results from
pharmacological and molecular modeling studies can be utilized for further optimization of identified
hits for selective inhibition of ACE.
Accepted 3 April 2015
Available online 6 April 2015
Keywords:
Quinazolinone derivatives
ACE inhibitory activity
Lisinopril
Docking studies
©
2015 Elsevier Masson SAS. All rights reserved.
1
. Introduction
important target for drug development in treating hypertension.
Discovery of Captopril [11], the first orally active ACE inhibitor,
encouraged researchers, worldwide to design and develop ACE
inhibitors (using the structure of carboxy peptidase) and were
clinically tested [12]. After Captopril, Lisinopril, Moexipril [13],
Quinapril [14] and other several ACE inhibitors have been invented
(Fig. 1), but those were hampered by common side effects like skin
rash, loss of taste and dry cough in patients on long term treatment.
Recent studies have demonstrated that the early combination
therapy of Carvedilol and an ACE inhibitor in mild heart failure and
left ventricular systolic dysfunction [15,16]. The addition of Carve-
dilol to ACE inhibitor and other routine heart failure therapy results
in a valuable improvement in the heart failure patients [17e22].
Inspite of considerable therapeutic advances, chronic heart
failure diseases (CHF) remained responsible for 27% deaths
worldwide, with 80% occurring in developing countries [1,2].
Several new developments in heart failure therapy have proven
benefits in survival and clinical well being. ACE inhibitors are
widely used for CHF diseases, which were developed in the late
1970s and early 1980s. ACE is a central component of the renin
angiotensin system (RAS) [3e6], it plays a vital role in blood
regulation, it controls not only blood pressure and fluid and elec-
trolyte homeostasis but also renal and vascular function and
mycocardina remodeling [7,8]. Recent development in clinical trials
are ACE inhibitors,
b-blockade and aldosterone receptor antago-
Therefore, the design of both ACE inhibitor and b-blocker activity
nisms to reduce mortality and morbidity in patients with chronic
heart failure (CHF) [9,10]. Driven by clinical evidence which dem-
onstrates the morbidity and mortality benefits, ACE has become an
by structure-based drug discovery is expected to produce next
generation drugs that might be safer and more effective [23]. Thus,
it becomes our interest to develop new therapy of a combined ACE
inhibitor and a b-blocker in CHF treatment.
A survey of literature revealed that quinazolin-4(3H)-one and
their derivatives have received much attention during recent years
due to its versatile biological activities such as anticonvulsant
*
Corresponding author.
E-mail addresses: lnagarapuiict@yahoo.com, nagarapu@iict.res.in (L. Nagarapu).
http://dx.doi.org/10.1016/j.ejmech.2015.04.009
223-5234/© 2015 Elsevier Masson SAS. All rights reserved.
0

R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
23
Fig. 1. Structure of Carvedilol, Captopril, Lisinopril, Moexipril, Quinapril and 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-phenylquinazolin-4(3H)-one derivatives (9aeg).
[24e28] and CNS depressant activity [29,30]. Our on-going
4
reflux temperature for 2 h followed by oxidation with KMnO in
research programme is on the development of quinazolin-4(3H)-
one derivatives [31e36]. Here in we devised the efficient
synthesis of 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-
phenylquinazolin-4(3H)-one derivatives which has ACE inhibitory
activity. The pharmacophore of quinazolin-4(3H)-one was designed
through rational drug design and molecular hybridization
approach. In addition, their ACE inhibition activity computational
study was carried out to highlight the probable binding mode, key
active site residue interactions and pharmacokinetic parameters
acetone at reflux condition for 8 h (Scheme 2) [39]. The synthesis of
4-(oxiran-2-ylmethoxy)-9H-carbazole (8) have been achieved by
the reaction between 4-hydroxy carbazole (6) and epichlorohydrin
(7) in presence of potassium carbonate at reflux temperature in
acetone for 24 h (Scheme 3). The synthesis of quinazolinone-
carbazole hybrids (9aeg) have been achieved in moderate to
excellent yields by the reaction between quinazolin-4(3H)-one
derivatives (3a,b;5aee) and 4-(oxiran-2-ylmethoxy)-9H-carba-
zole(8)in the presence of potassium carbonate and a catalytic
amount of Tetrabutylammoniumiodide (TBAI) at reflux tempera-
ture in acetonitrile for 36 h (Scheme 4) [40]. The structures of all the
[
(
37,38]. In this study, Lisinopril-tryptophan bound crystal structure
PDB ID: 3L3N) of human ACE was considered followed by a
1
docking study for prediction of their binding affinity. A pharma-
cophore modeling approach is also employed here, to help in un-
derstanding the key structural features of the ligand responsible for
inhibition.
synthesized compounds were confirmed by spectral data (FTIR, H
13
NMR, C NMR and ESI-MS). The target model compound 9e was
þ
evident from the appearance of [M þ H] peak at m/z 476 in the
ꢀ1
mass spectrum (ESI), eCHeOH stretching at 1101 cm in IR and
from the characteristic CH proton as doublet of doublet at
d 4.63
1
with coupling constant J ¼ 13.42 Hz and 13.58 Hz in H NMR.
. Pharmacology
Angiotensin converting enzyme (ACE) inhibitory activity of
2
. Results and discussion
3
2.1. Chemistry
The synthesis of desired quinazolin-4(3H)-one derivatives could
newly synthesized compounds was examined in vitro using
recently developed high-throughput colorimetric screening
method [41,42]. Most of these anti-hypertensive peptides have
be obtained by the reaction between anthranilamide (1) and
different anhydrides in the presence of pyridine and a catalytic
amount of N,N-Dimethyl amino pyridine(DMAP) in dichlor-
omethane(DCM) for 3h and followed by condensation with 1 N
KOH in ethanol/water (1:1) system for 30 min to produce corre-
sponding cyclic compounds (3a,b) in good yields (Scheme 1). The
cyclic compounds, 2-Aryl quinazolin-4(3H)-one derivatives (5aee)
have been achieved in two steps starting from anthranilamide (1).
The first synthetic step involved the condensation of anthranila-
mide (1) with aromatic aldehydes and a catalytic amount of Tet-
rabutyl ammonium hydrogensulphate(TBAHS) in methanol under
Scheme 2. Synthesis of 2-aryl quinazolin-4(3H)-one derivatives. Reagents and con-
Scheme 1. Synthesis of quinazolin-4(3H)-one. Reagents and conditions: i) Anhydrides,
Pyridine, DMAP, DCM, rt, 3 h. ii) 1 N KOH, EtOH: H O (1:1), reflux, 30 min.
2
ditions: i) Substituted aldehydes, TBAHS, MeOH, 2 h, reflux. ii) KMnO
reflux.
4
, Acetone, 8 h,

24
R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
Scheme 3. Synthesis of 4-(oxiran-2-ylmethoxy)-9H-carbazole. Reagents and condi-
tions: i) K CO , Acetone, reflux, 24 h.
2
3
been characterized by the rabbit lung ACE inhibitor assay, based on
the hydrolysis of the synthetic peptide hippurylehistidyleleucine
(
HHL). Angiotensin converting enzyme (ACE) hydrolyzes HHL to
hippuric acid (HA) and histidyleleucine (HL). HA released is
directly proportional to the ACE activity. In this screening method,
the released hippuric acid from the substrate hippur-
ylehistidyleleucine (HHL) was transformed into yellow color by
mixing with pyridine and benzene sulfonyl chloride. The resulted
yellow color was determined colorimetrically at absorbance
Fig. 2. In vitro Angiotensin Converting Enzyme (ACE) inhibition of new analogs and
standard (STD) drug, Lisinopril.
4
10 nm. The average ACE inhibitor activity was measured in trip-
licate for new analogs 9aeg and the standard drug Lisinopril
Fig. 2). The experiment carried out at 1.0 M concentration of test
(
m
compounds 9aeg revealed 17e100% of ACE inhibition activity.
Among them three compounds 9b, 9c and 9e have shown better
ACE inhibitory activity (>75%) compared to that of the other
substituted analogs. Relating to the reference drug Lisinopril these
three analogs 9b, 9c and 9e were comparably active with 82.9%,
100% and 100% ACE inhibition, respectively (Fig. 2). SAR studies
showed that the substitution of electron donating group on qina-
zolinone ring resulted in higher % of ACE inhibitory activity (see
Fig. 3).
Fig. 3. Dose response curves of new derivatives 9b, 9c & 9e for ACE inhibition.
4
. Molecular modeling studies
4.1. Analysis of Lisinopril and 9e binding modes in ACE active site
To support our hypotheses we have performed molecular
modeling studies on ACE to understand the proteineligand in-
teractions and their binding modes as compared to Lisinopril. Even
though 9e and 9c exhibit apparently similar level of ACE-inhibition,
we chose 9e over 9c for molecular modeling studies. This was based
4.1.1. Lisinopril drug
The 1-carboxy moiety of Lisinopril [N -[(1S)-1-carboxy-3-
phenylpropyl]- -lysyl- -proline] forms a network and showed
hydrogen bonding and charged interaction with surrounding resi-
dues which include His383, His387, Glu411, Glu384. The His383,
2
L
L
on the fact that 9e was more ACE-inhibiting than 9c at 10 mM.
2 3 3
Scheme 4. Synthesis of 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)quinazolin-4(3H) one derivatives. Reagents and conditions: i) K CO , TBAI, CH CN, reflux, 36 h.

R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
25
þ2
His387 residues showed Zn mediated interaction with caroxylate
with His383, His387 residues. The nitrogen (N1) of quinazolinone
moiety showed hydrogen bonding interactions with His513 and
His353. The nitrogen of carbazole moiety showed hydrogen
bonding interaction with hydroxyl group of Tyr360. The carbazole
moiety has showed hydrophobic interactions with Ala63, Phe391,
Trp357 and Tyr360 residues. The quinazolinone moiety was also
oriented towards hydrophobic pocket and showed interactions
with Tyr523, Phe457, Phe460 and Trp279 residues. Further sub-
stitution of hydrophobic moieties with electron-donating groups
might be beneficial for enhancing its potency against ACE. The
substituted hydrophobic moieties at 2nd position of quinazolinone
ring could be favorable for enhancing its potency by interacting
with neighboring hydrophobic residues i.e Phe512, Val518 and
Val351. Further the substituted nitro group (9d) at 2nd position of
quinazolinone ring was detrimental to the activity because the
nitro group was oriented in close proximity to Glu143. For key
active site residues around 5 Å see Supplementary Information. The
probable binding mode of most potent compound (9e) in quina-
zolinone series and reference compound Lisinopril are depicted in
moiety. The N2 moiety have shown hydrogen bonding interactions
with Ala354 backbone residue and sidechain His353 residue. The
charged amino group in lysine part of the ligand showed hydrogen
bonding interactions with sidechain Asp377 and Glu162 residues.
The carboxy group of proline showed hydrogen bonding in-
teractions with sidechain Glu281, Lys511, Tyr520 residues. The
proline has also showed hydrophobic interactions with Tyr520,
Phe457 and Tyr523. The carbonyl moiety connected to proline
showed interaction with His513 residue. The phenylprolyl moiety
showed hydrophobic interactions with Val518, Phe512, Trp357
and Val351. The hydrophobic part of Lys moiety of Lisinopril
was surrounded by two hydrophobic Ala354, Val380 residues
(Figs. 4 and 5).
4.1.2. Compound 9e
Similar to Lisinopril, carbonyl moiety of quinazolinone and
linker hydroxyl group of compound (9e) showed hydrogen bonding
interactions with Glu411, Glu384 and Zn mediated interactions
þ2
þ2
Fig. 4. Binding mode of reference Lisinopril (cyan) and 9e in the active sites of ACE, the hydrogen bond interactions are shown in pink color dotted lines, Zn is shown in sphere in
ash color, he important residues are shown in green color and protein cartoon is represented in wheat color. (For interpretation of the references to color in this figure legend, the
reader is referred to the web version of this article.)

26
R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
þ2
Fig. 5. A: Probable binding mode of 9e (orange) in the active sites of ACE, the hydrogen bond interactions are shown in pink color dotted lines, Zn is shown in sphere in ash color,
the important residues are shown in green color and protein cartoon is represented in wheat color. B: 2D-ligand interaction plot and C: Surface active site pocket of ACE with 9e. (For
interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 6. A: Seven featured (AAADDRR) Pharmacophore hypothesis; A: hydrogen bond acceptor, D: hydrogen bond donor, R: aromatic ring.

R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
27
Figs. 4 and 5. Also we have identified common pharmacophore
hypothesis from the best docked poses of most potent compounds
and is shown in Fig. 6.
The crude product obtained was purified by flash column chro-
matography over silica gel (20:80, ethyl acetate/hexane) to afford
compounds 2aeb.
2
The obtained acylated product was dissolved in EtOH: H O (1:1)
5
. Conclusion
and 1 N KOH was added at room temperature. After heating at
reflux temperature for 0.5 h, the reaction mixture was cooled to RT
and then generated solid was filtered, recrystallized from EtOH to
give quinazolin-4(3H)-one derivatives 3a,b in the form of white,
dense needles.
In summary, we have developed and synthesized a novel class of
ACE inhibitors. Most of the prepared compounds have been showed
ACE inhibitory activity in enzyme based assays. Compounds 9b, 9c
and 9e were found to be potent ACE inhibitors. The computational
techniques such as molecular docking and pharmacophore studies
have been applied to support our experimental results. From our
investigation we found that Lisinopril and our most potent com-
pound 9e have shown common hydrogen bonding interactions
6.2.1. 2-(Trifluoromethyl)quinazolin-4(3H)-one (3b)
1
Yield 81%; H NMR (300 MHz, CDCl
3
):
d
7.62 (t, J ¼ 7.17 Hz,
7.55 Hz, 1H, AreH), 7.77e7.91 (m, 2H, AreH), 8.29 (d, J ¼ 7.93 Hz,
13
3
1H, AreH); C NMR (75 MHz, CDCl ): d 115.63, 119.21, 122.24,
þ2
with Glu411, Glu384 and Zn mediated interactions with His383,
127.84, 128.24, 134.46, 146.33, 161.44.
His387 residues, which are critical to access maximum ACE inhib-
itory potency. Apart from the common interactions compared to
Lisinopril, our compounds especially quinazolinone moiety were
explored in a hydrophobic binding pocket surrounded by Tyr523,
Phe457, Phe460 and Trp279 residues. Substitution of lipophilic
moieties along with electron-donating groups in hydrophilic
pocket might be beneficial for enhancing its potency against ACE.
The obtained pharmacophore and docking results may afford
valuable clues to optimize the quinazolinone lead compound for
the potent and selective inhibition of ACE. The results presented
6.3. General procedure for the synthesis of 5aee
A solution of 2-aminobenzamide (1 g, 0.007 mol), aromatic
aldehyde (0.007 mol) and a catalytic amount of TBAHS (1 mol%) in
MeOH was made to react at reflux temperature for 2 h. The reaction
mixture was then cooled to room temperature and small amount of
water (5 mL) was added to the mixture, and then generated solid
was filtered to give cyclic compound 4aee. Intermediates 4aee
were totally converted into 5aee, by the oxidation with KMnO
4
here may help in understanding of their
further investigations.
b
-blocker activity and
(0.018 mol) in acetone under reflux conditions for 8 h, The obtained
solid was recrystallized from EtOH to give 2-aryl quinazolin-4(3H)-
one derivatives 5aee in the form of long, white, dense needles.
6
. Experimental section
6
.3.1. 2-Phenylquinazolin-4(3H)-one (5a)
1
6
.1. Chemistry
Yield 90%; H NMR (300 MHz, CDCl
3
):
d
7.51 (t, J ¼ 7.55 Hz, 1H,
AreH), 7.59 (br, 4H, AreH), 7.84 (s, 1H, AreH), 8.23e8.39 (m, 3H,
AreH), 11.80 (br, 1H, NH); C NMR (75 MHz, CDCl ): 120.62,
125.48, 125.74, 127.11, 128.05, 130.64, 132.47, 133.73, 148.68, 151.85,
162.55.
13
All the chemicals and reagents were purchased from Sigma-
eAldrich and SD Fine-Chemicals, Pvt. Ltd. India, and used as
received. The reactions were monitored and R value were deter-
3
d
f
mined using analytical thin layer chromatography (TLC) with
Merck Silica gel 60e120 and F254 pre-coated plates (0.25 mm
thickness). Spot on the TLC plates were visualized using ultraviolet
light (254 nm). Flash column chromatography was performed with
Merck silica gel (100e200 mesh). Melting points were determined
6.3.2. 2-(p-Tolyl)quinazolin-4(3H)-one (5c)
1
Yield 90%; H NMR (300 MHz, CDCl
3
):
d
2.43 (s, 3H, CH
3
), 7.31 (d,
J ¼ 7.93 Hz, 2H, AreH), 7.40e7.50 (m, 1H, AreH), 7.76 (d, J ¼ 3.77 Hz,
2H, AreH), 8.10 (d, J ¼ 8.12 Hz, 2H, AreH), 8.25 (d, J ¼ 7.74 Hz, 1H,
1
13
in capillaries and are uncorrected. H NMR spectra were recorded
AreH), 11.82e12.45 (br, 1H, NH); C NMR (75 MHz, CDCl
3
):
d
21.52,
on Bruker DRX-300, Varian 400 and Varian-500 NMR spectrome-
120.75, 126.33, 126.51, 127.27, 127.87, 129.72, 129.94, 134.80, 142.15,
149.59, 151.74, 163.85.
ters. 13C NMR spectra were recorded on Bruker DRX-300. Proton
chemical shifts are reported in ppm (
methylsilane (TMS, 0.00) or with the solvent reference relative to
TMS employed as the internal standard (CDCl 7.26; DMSO-d
2.54) and multiplicities of NMR signals are designated as s
singlet), d (doublet), t (triplet), q (quartet), br (broad), m (multi-
d) relative to internal tetra-
d
6.3.3. 2-(4-Fluorophenyl)quinazolin-4(3H)-one (5d)
1
3
,
d
6
Yield 90%; H NMR (300 MHz, CDCl
8.68 Hz, 2H, AreH), 7.47 (t, J ¼ 7.93 Hz,1H, AreH), 7.66e7.85 (m, 2H,
3
):
d
7.21 (t, J ¼ 8.49 Hz,
d
(
AreH), 8.19e8.40 (m, 3H, AreH).
plet, for unresolved lines). Infrared (IR) spectra were recorded on a
Perkin Elmer FT-IR 400 spectrometer; data is reported in wave
6.3.4. 2-(2,4-Dichlorophenyl)quinazolin-4(3H)-one (5e)
ꢀ1
1
numbers (cm ). Mass spectra were recorded on Agilent Technol-
ogies 1100 Series (Agilent Chemistation Software). High-resolution
mass spectra (HRMS) were obtained by using ESI-QTOF mass
spectrometry. All computations and molecular modeling studies
have been carried out on Schrodinger software.
Yield 90%; H NMR (300 MHz, CDCl
3
):
d
7.48e7.58 (m, 2H,
AreH), 7.63e7.74 (m, 3H, AreH), 7.82 (t, J ¼ 6.98 Hz, 8.12 Hz, 1H,
13
AreH), 8.20 (d, J ¼ 7.93 Hz, 1H, AreH); C NMR (75 MHz, CDCl
3
):
d
119.65,124.08, 125.15,125.51, 125.67, 127.43, 130.27, 130.91,131.20,
132.49, 133.98, 146.82, 149.50.
6.2. General procedure for the synthesis of 3aeb
6.4. General procedure for the synthesis of compound 8
To a stirred solution of anthranilamide (1 g, 0.007 mol) in DCM
20 ml), substituted anhydrides (0.008 mol), pyridine (0.95 mL) and
To a suspension of 4-hydroxy carbazole (5 g, 0.027 mol) and
CO (7.54 g, 0.054 mol) in acetone (80 mL), epichlorohydrin
(
K
2
3
DMAP (2 mol%) were added at RT. The reaction mixture was stirred
at RT for 3 h. After completion of the reaction, as indicated by TLC,
the reaction mixture was diluted with water (10 mL) and extracted
with DCM (3 ꢁ 10 mL). The DCM extracts were combined, dried
(2.50 mL, 0.032 mol) was added. The reaction mixture was refluxed
for 24 h. After completion of the reaction, as indicated by TLC, the
acetone in the reaction mixture was removed under reduced
pressure. The obtained residue was dissolved in ethyl acetate
(75 mL), organic phase was washed with water (3 ꢁ 15 mL),
2 4
with Na SO and evaporated to dryness under reduced pressure.

28
R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
separated, dried with Na
2
SO
4
, evaporated under reduced pressure
6.5.4. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-(4-
and purified by column chromatography over silica gel (25:75, ethyl
acetate/hexane) to afford 8 as solid compound.
nitrophenyl)quinazolin-4(3H)-one (9d)
ꢂ
ꢀ1
Yield 71%; mp 101e104 C; IR (KBr)
y
in cm : 1104, 1349, 1682,
2924, 3420; H NMR (500 MHz, CDCl ): 3.88e3.94 (dd,
J ¼ 11.44 Hz and 11.90 Hz, 1H , CH ), 3.97e4.03 (dd, J ¼ 11.44 Hz,
1H , CH ), 4.36 (dd, 1H, CH),
), 4.12e4.17 (dd, J ¼ 11.90 Hz, 2H, CH
Yield 64%; mp 167e169 C; 1H NMR (300 MHz, CDCl
ꢂ
):
), 2.90e2.97 (dd, J ¼ 4.34,
), 3.50e3.57 (m, 1H , CH), 4.04e4.14 (dd,
, CH ), 6.70 (d,
1
d
3
3
d
4
2.81e2.88 (dd, J ¼ 2.45, 2.64 Hz,1H
.91 Hz, 1H , CH
, CH
a
, CH
2
a
2
b
2
c
b
2
2
J ¼ 6.23 Hz, 1H
e
2
), 4.52e4.59 (dd, J ¼ 2.26 Hz, 1H
d
2
6.66e6.70 (dd, J ¼ 7.78 Hz, 1H, AreH), 7.06e7.09 (dd, J ¼ 8.08 Hz,
1H, AreH), 7.11e7.14 (dd, J ¼ 8.54 Hz and 8.69 Hz,1H, AreH), 7.24 (s,
1H, AreH), 7.31 (d, J ¼ 3.81 Hz, 1H, AreH), 7.33 (d, J ¼ 3.96 Hz, 1H,
AreH), 7.34 (d, J ¼ 3.81 Hz, 1H, AreH), 7.36 (s, 1H, AreH), 7.38e7.42
J ¼ 7.93 Hz, 1H, AreH), 7.05e7.20 (m, 2H, AreH), 7.25e7.39 (m, 2H,
AreH), 7.46 (d, J ¼ 7.93 Hz,1H, AreH), 8.17 (d, J ¼ 7.14 Hz,1H, AreH),
þ
1
1.27 (s, 1H, NH); ESI MS: m/z ¼ 239 [M ].
(
d, J ¼ 8.85 Hz, 2H, AreH), 7.53 (d, J ¼ 8.69 Hz, 1H, AreH), 7.95 (t,
6.5. General procedure for the synthesis of 9aeg
J ¼ 8.69 Hz and 9.00 Hz, 1H, AreH), 8.14e8.19 (br, 1H, AreH), 8.21
13
(
d, J ¼ 7.62 Hz, 1H, AreH), 8.28 (t, J ¼ 8.69 Hz, 1H, AreH); C NMR
A mixture of 2-methyl quinazolin-4(3H)-one 3a (150 mg,
.937 mmol), 4-(oxiran-2-ylmethoxy)-9H-carbazole (8, 222 mg,
.937 mmol), potassium carbonate (258 mg, 1.875 mmol) and tet-
(125 MHz, CDCl ): 48.10, 62.32, 69.94, 96.29, 100.04, 106.26,
3
d
0
0
108.39, 117.73, 118.01, 120.08, 121.10, 123.76, 124.79 (2C), 126.02,
128.07, 132.92,134.56,138.20,140.01,153.04, 155.57,161.02; ESI MS:
þ
rabutylammoniumiodide (5 mg, 0.014 mol) were heated in aceto-
m/z ¼ 507 [M þ H] ; HRMS calculated for C29
22 4 5
H N O : 507.1600,
ꢂ
nitrile (15 mL) at 80 C for 36 h under nitrogen atmosphere. The
Found: 507.1705.
reaction mass was extracted with ethyl acetate, separated and the
organic layer was dried over sodium sulfate and concentrated. The
crude product was purified by column chromatography over silica
gel (65:35, ethyl acetate/hexane) to give following compounds:
6.5.5. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-(p-tolyl)
quinazolin-4(3H)-one (9e)
ꢂ
ꢀ1
Yield 80%; mp 97e100 C; IR (KBr)
y
in cm : 1101, 1346, 1607,
): 2.13 (s, 3H, CH ),
), 4.42e4.52 (dd,
), 4.63 (dd, J ¼ 13.42 Hz and
1
2
923, 3404; H NMR (500 MHz, CDCl
3
d
3
6.5.1. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-
4.07e4.23 (dd, J ¼ 14.80 Hz and 15.25 Hz, 2H, CH
2
methylquinazolin-4(3H)-one (9a)
J ¼ 13.58 Hz and 17.09 Hz, 2H, CH
2
ꢂ
ꢀ1
Yield 77%; mp 111e114 C; IR (KBr)
y
in cm : 1096, 1631, 2923,
2.78 (s, 3H, CH ), 4.39 (d,
), 4.53 (s, 1H , CH ), 4.57 (d,
), 4.61e4.71 (m, 1H, CH), 6.72 (d, J ¼ 7.55 Hz,
H, AreH), 7.10 (d, J ¼ 7.55 Hz, 1H, AreH), 7.32e7.52 (m, 4H, AreH),
.66 (d, J ¼ 7.55 Hz, 1H, AreH), 7.72e7.80 (m, 1H, AreH), 8.13 (s, 1H,
13.58 Hz, 1H, CH), 6.55 (d, J ¼ 7.93 Hz, 1H, AreH), 7.01e7.10 (dd,
J ¼ 20.75 Hz and 21.05 Hz, 2H, AreH), 7.14e7.18 (m, 1H, AreH), 7.28
(d, J ¼ 8.08 Hz, 1H, AreH), 7.35e7.42 (dd, J ¼ 10.07 Hz and 15.10 Hz,
3H, AreH), 7.53 (t, J ¼ 6.71 Hz, 1H, AreH), 7.73e7.80 (m, 2H, AreH),
7.92 (d, J ¼ 7.78 Hz, 1H, AreH), 8.16 (s, 1H, AreH), 8.36 (d,
1
3
435; H NMR (300 MHz, CDCl
3
):
, CH
d
3
J ¼ 5.28 Hz, 1H
a
, CH
, CH
2
), 4.50 (s, 1H
b
2
a
2
J ¼ 3.02 Hz, 1H
b
2
1
13
7
J ¼ 7.93 Hz, 1H, AreH); C NMR (125 MHz, CDCl
3
): d 21.09, 49.66,
1
3
AreH), 8.28 (d, J ¼ 8.30 Hz, 2H, AreH); C NMR (125 MHz, CDCl
29.70, 48.40, 66.29, 69.83, 104.31, 109.79, 110.21, 119.71, 122.66,
26.74, 129.97, 130.89, 131.12, 134.01, 135.20, 141.33, 142.41, 145.58,
48.34, 151.85, 154.58, 157.32, 160.40, 160.52; ESI MS: m/z ¼ 400
3
):
69.28, 69.69, 100.90, 103.97, 109.89, 112.56, 119.61, 120.42, 122.23,
122.88, 124.90 (2C), 126.46, 126.74, 127.12, 127.46 (2C), 127.95,
129.32, 132.04,134.70,138.62,140.09,140.84,147.22,154.60,156.50,
d
1
þ
1
164.12; ESI MS: m/z ¼ 476 [M þ H] ; HRMS calculated for
þ
[M þ H] ; HRMS calculated for C24
H
21
N
3
O
3
: 400.1600, Found:
30 25 3 3
C H N O : 476.1900, Found: 476.1966.
4
00.1666.
6.5.6. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-(4-
6
.5.2. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-
fluorophenyl)quinazolin-4(3H)-one (9f)
ꢂ
ꢀ1
(
trifluoromethyl)quinazolin-4(3H)-one (9b)
Yield 72%; mp 116e119 C; IR (KBr)
y
):
in cm : 1025, 1102, 1668,
4.21 (d, J ¼ 4.42 Hz, 1H
, CH
), 4.48e4.58 (m, 1H, CH), 6.57 (d, J ¼ 7.93 Hz,
ꢂ
ꢀ1
1
Yield 72%; mp 99e102 C; IR (KBr)
y
):
in cm : 1099, 1213, 1607,
3.80e4.11 (m, 2H, CH ),
2254, 3439; H NMR (500 MHz, CDCl
3
d
a
,
2
),
1
2
4
1
7
(
1
1
1
927, 3401; H NMR (300 MHz, CDCl
.30e4.39 (m, 2H, CH
H, AreH), 7.07 (d, J ¼ 8.30 Hz, 1H, AreH), 7.30e7.47 (m, 3H, AreH),
.51e7.68 (m, 2H, AreH), 7.87 (d, J ¼ 3.77 Hz, 1H, AreH), 8.08e8.17
m, 1H, AreH), 8.22 (d, J ¼ 8.30 Hz, 1H, AreH), 8.35 (d, J ¼ 8.30 Hz,
H, AreH); 13C NMR (125 MHz, CDCl
): 53.64, 68.40, 71.24, 101.24,
04.10, 110.12, 119.75, 122.35, 122.70, 124.99, 126.67, 126.86, 128.71,
29.28, 135.52, 136.64, 139.29, 140.98, 143.42, 150.59, 154.42,
3
d
2
CH
2
), 4.30e4.33 (s, 1H
, CH
2
b
, CH
2
), 4.41e4.44 (dd, J ¼ 2.59 Hz, 1H
a
2
), 4.42e4.67 (m, 1H, CH), 6.68 (d, J ¼ 8.30 Hz,
4.45e4.47 (m, 1H
b
1H, AreH), 6.67 (d, J ¼ 7.93 Hz, 1H, AreH), 6.93 (t, J ¼ 8.54 Hz, 1H,
AreH), 7.07 (t, J ¼ 8.08 Hz and 10.37 Hz, 1H, AreH), 7.17 (t,
J ¼ 7.78 Hz and 7.93 Hz, 1H, AreH), 7.40 (t, J ¼ 6.56 Hz, 1H, AreH),
7.50 (dd, J ¼ 8.39 Hz and 8.54 Hz, 1H, AreH), 7.55 (t, J ¼ 7.32 Hz and
7.78 Hz,1H, AreH), 7.74 (d, J ¼ 7.78 Hz,1H, AreH), 7.78e7.83 (m, 1H,
AreH), 7.90 (d, J ¼ 7.78 Hz, 1H, AreH), 8.11e8.17 (m, 1H, AreH), 8.22
(d, J ¼ 7.78 Hz, 1H, AreH), 8.30 (d, J ¼ 7.78 Hz, 1H, AreH), 8.37 (d,
3
d
þ
1
54.83, 160.82, 162.09; ESI MS: m/z ¼ 476 [M þ Na] ; HRMS
13
calculated for C24 : 476.1300, Found: 476.1409.
H
18
F
3
N
3
O
3
J ¼ 7.32 Hz, 1H, AreH); C NMR (75 MHz, CDCl
3
): d 49.37, 66.56,
69.71, 99.79, 103.69, 109.65, 111.79, 114.86, 115.15, 118.45, 120.36,
6.5.3. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-
121.58,122.34, 124.08, 125.66,126.12,126.42,126.84,130.33,130.44,
phenylquinazolin-4(3H)-one (9c)
131.25, 133.87, 138.60, 140.84, 146.67, 154.21, 155.50, 162.34, 164.20;
ꢂ
ꢀ1
þ
Yield 78%; mp 105e108 C; IR (KBr)
y
in cm : 1107, 1262, 1667,
): 4.05e4.20 (m, 5H,
ꢁ CH2, 1 ꢁ CH), 6.52 (s, 1H, AreH), 7.01e7.15 (m, 2H, AreH),
ESI MS: m/z ¼ 480 [M þ H] ; HRMS calculated for C29
3 3
H22FN O :
2
2
926, 3326; 1H NMR (300 MHz, CDCl
3
d
480.1600, Found: 480.1716.
7
.21e7.45 (m, 6H, AreH), 7.49e7.64 (m, 3H, AreH), 7.74 (s, 2H,
AreH), 8.02 (d, J ¼ 7.55 Hz, 1H, AreH), 8.35 (s, 1H, AreH), 9.90 (s,
H, NH); 13C NMR (75 MHz, CDCl
): 48.37, 64.96, 69.08, 98.80,
02.79, 108.81, 110.61, 117.46, 119.51, 120.59, 121.51, 123.09, 124.83,
25.11, 125.33, 125.84, 126.92, 127.36 (2C), 128.06, 132.87, 134.37,
6.5.7. 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-(2,4-
dichlorophenyl) quinazolin-4(3H)-one (9g)
ꢂ
ꢀ1
1
1
1
3
d
Yield 84%; mp 112e115 C; IR (KBr)
y
in cm : 1025, 1102, 1680,
3.99e4.13 (m, 1H , CH ),
), 4.47e4.64 (m, 1H , CH ), 4.75
1
2924, 3418; H NMR (300 MHz, CDCl
3
):
d
a
2
4.18 (s, 1H
b
, CH
2
), 4.32 (s, 1H
a
, CH
2
b
2
1
37.76, 140 (2C), 145.89, 153.36, 155.55, 160.98; ESI MS: m/z ¼ 462
(dd, 1H, CH), 6.45 (d, J ¼ 7.55 Hz, 1H, AreH), 6.55 (d, J ¼ 7.74 Hz, 1H,
AreH), 6.71 (d, J ¼ 7.55 Hz, 1H, AreH), 7.06 (d, J ¼ 7.55 Hz, 1H,
AreH), 7.13e7.37 (m, 2H, AreH), 7.38e7.45 (m, 1H, AreH),
þ
[M þ H] ; HRMS calculated for C29
23 3 3
H N O : 462.1700, Found:
4
62.1806.

R. Venkatesh et al. / European Journal of Medicinal Chemistry 96 (2015) 22e29
29
7
.46e7.50 (m, 1H, AreH), 7.55 (t, J ¼ 8.12 Hz, 1H, AreH), 7.68e7.83
Appendix A. Supplementary data
(
m, 2H, AreH), 7.92 (d, J ¼ 6.42 Hz, 1H, AreH), 8.18 (d, J ¼ 7.17 Hz,
1
H, AreH), 8.36 (d, J ¼ 7.93 Hz,1H, AreH), 10.59e10.80 (m, 1H, NH);
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.ejmech.2015.04.009.
1
3
C NMR (75 MHz, CDCl
09.50, 111.44, 118.24, 120.46, 121.33, 122.12, 123.84, 125.45, 125.86,
26.66, 128.04, 130.54, 132.01, 132.33, 132.51, 133.67, 135.25, 135.46,
38.41, 140.62, 146.50, 152.89, 154.02, 161.22; ESI MS: m/z ¼ 530
3
): d 49.21, 66.06, 69.54, 99.58, 103.49,
1
1
1
References
þ
[
5
M þ H] ; HRMS calculated for C29
2 3 3
H21Cl N O : 530.1000, Found:
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