Design, synthesis and evaluation of substituted N-(3-arylpropyl)-9,10- dihydro-9-oxoacridine-4-carboxamides as potent MDR reversal agents in cancer

Article abstract of DOI:10.1002/cjoc.201190113

A novel class of molecules with structure N-(3-arylpropyl)-9,10-dihydro-9- oxoacridine-4-carboxamides (20-29) were designed by generating a pharmacophore for potent MDR reversal activity using phase drug design software. The designed molecules were synthesized by a novel synthesis route and evaluated for their inhibitory effects on the transport activity of P-glycoprotein (P-gp) by standard Hoechst 33342 assay method. Based on the pIC₅₀ values of ten title compounds screened, three compounds exhibited better activity as compared to Verapamil used as standard.

Full text of DOI:10.1002/cjoc.201190113

FULL PAPER
Design, Synthesis and Evaluation of Substituted
N-(3-Arylpropyl)-9,10-dihydro-9-oxoacridine-4-carboxamides
as Potent MDR Reversal Agents in Cancer
Velingkar, V. S.*
Dandekar, V. D.
Department of Pharmaceutical Chemistry, Prin. K. M. Kundnani College of Pharmacy, Cuffe Parade, Mumbai
4000005, India
A novel class of molecules with structure N-(3-arylpropyl)-9,10-dihydro-9-oxoacridine-4-carboxamides (20—
29) were designed by generating a pharmacophore for potent MDR reversal activity using phase drug design soft-
ware. The designed molecules were synthesized by a novel synthesis route and evaluated for their inhibitory effects
on the transport activity of P-glycoprotein (P-gp) by standard Hoechst 33342 assay method. Based on the pIC50
values of ten title compounds screened, three compounds exhibited better activity as compared to Verapamil used as
standard.
Keywords N-(3-arylpropyl)-9,10-dihydro-9-oxo-acridine-4-carboxamides, MDR reversal agents, pharmacophore,
phase drug design software, structure-activity relationships, structure elucidation
N-(3-arylpropyl)-9,10-dihydro-9-oxoacridine-4-carbox-
amides were designed by pharmacophore generation
approach using phase drug designing software
(SCHRODINGER, INC).
Introduction
Multidrug resistance (MDR) is associated with the
overexpression of P-glycoprotein (P-gp), resulting in
increased efflux of cytotoxic drugs from cancer cells.
Inhibiting P-gp as a method to reverse MDR in cancer
patients has been studied extensively, but the results are
generally disappointing.
First-generation agents like verapamil, cyclosporin
(cyclosporin A), tamoxifen, and several calmodulin an-
tagonists were limited by unacceptable toxicity,1-3
whereas second-generation agents including dexvera-
pamil, dexniguldipine, valspodar (PSC 833), and biri-
codar (VX-710) had better tolerability but were con-
founded by unpredictable pharmacokinetic interactions
and interactions with other transporter proteins.4-6
Third-generation inhibitors including tariquidar
(XR9576), zosuquidar (LY335979) and substituted di-
arylimidazole (ONT-093) have high potency and speci-
ficity for P-gp.5,7,8 The continued development of these
agents may establish the true therapeutic potential of
P-gp-mediated MDR reversal.
The present work is aimed towards development of
potent and selective MDR reversal agent for treating
MDR in cancer. It is proposed to achieve this by gener-
ating pharmacophore from the literature reported com-
pounds of MDR reversal agents belonging to
9,10-dihydro-9-oxoacridine-4-carboxamide class by
designing novel series of compounds, synthesizing by
novel synthetic method and evaluating them.
Synthesis of substituted N-(3-arylpropyl)-9,10-
dihydro-9-oxoacridine-4-carboxamide analogs involved
condensation of o-bromobenzoic acid (1) with an-
thranilic acid (2) in the presence of copper powder and
anhydrous potassium carbonate in ethanol to get
2,2'-iminobisbenzoic acid (3) which on cyclization with
concentrated sulfuric acid produced 9,10-dihydro-9-
oxoacridine-4-carboxylic acid (4).10,11 9,10-Dihydro-9-
oxoacridine-4-carboxylic acid was converted to
9,10-dihydro-9-oxoacridine-4-carbonyl chloride (5) us-
ing thionyl chloride (Scheme 1).
Reduction of 3-chloropropiophenone (6) using so-
dium borohydride in methanol gave 3-chloro-1-phenyl-
1-propanol (7). This was further reacted with sodium
iodide in acetone to yield 3-iodo-1-phenyl-1-propanol
(8). This iodo alcohol on reaction with methylamine in
tetrahydrofuran gave 3-hydroxy-N-methyl-3-phenyl-
propylamine (9) and on reaction with ammonia yielded
3-hydroxy-3-phenylpropylamine (10).
Compounds 9 and 10 were respectively treated by
thionyl chloride to afford the corresponding derivatives
3-chloro-N-methyl-3-phenylpropylamine
(11)
and
3-chloro-3-phenylpropylamine (12). Both the chloro
propylamines (compounds 11 and 12) were individually
treated with phenol or o-cresol to get compounds 13—
16 (Scheme 2).
Compound 6 was reacted with sodium iodide in
acetone to produce 3-iodopropiophenone (17) which on
reaction with methylamine in tetrahydrofuran yielded
Results and discussion
A novel class of compounds with structure
*
E-mail: vsvelingkar@gmail.com; vikrantdandekar@gmail.com; Tel: 0091-022-22164387; Fax: 0091-022-22165282
Received June 24, 2010; revised and accepted November 20, 2010.
504
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2011, 29, 504— 510

N-(3-Arylpropyl)-9,10-dihydro-9-oxoacridine-4-carboxamides as Potent MDR Reversal Agents
carbodiimide (DCC) to get compounds 20 and 21
Scheme 1 Synthesis of compounds 4, 5
(Scheme 4). Condensation of compound 5 with com-
pounds 15 and 16 in presence of anhydrous potassium
carbonate in dimethylformamide at 70 ℃ for 6 h of-
fered compounds 22 and 23, respectively (Scheme 5).
Condensation of compound 5 with compounds 9, 18 and
11 individually using potassium carbonate in dimethyl-
formamide at 70 ℃ for 5 h gave compounds 24, 25 and
26 respectively (Scheme 6). Compound 4 was con-
densed with compounds 10, 19 and 12 respectively us-
ing DCC to give compounds 27, 28 and 29, respectively
(Scheme 7).
The substituted N-(3-arylpropyl)-9,10-dihydro-9-
oxoacridine-4-carboxamide analogs were screened to
evaluate their inhibitory effects on the transport activity
of P-glycoprotein (P-gp) by Standard Hoechst 33342
assay method.. It was observed that the test compounds
20, 21 and 22 exhibited better MDR reversal activity as
compared to the standard Verapamil. However, com-
pound 23 elicited comparable activity to that of the
standard. A decrease in activity was observed with re-
moval of 3-phenoxy ring.
3-(N-methylamino)propiophenone (18) and on reaction
with ammonia gave 3-aminopropiophenone (19)
(Scheme 3).
Further, compound 4 was condensed with com-
pounds 13 and 14 respectively using N,N'-dicyclohexyl-
Hence it may be concluded that among substituted
N-(3-arylpropyl)-9,10-dihydro-9-oxoacridine-4-carbox-
Scheme 2 Synthesis of compounds 13—16
Scheme 3 Synthesis of compounds 18, 19
Chin. J. Chem. 2011, 29, 504— 510
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
505

Velingkar & Dandekar
FULL PAPER
Scheme 6 Synthesis of compounds 24—26
Scheme 4 Synthesis of compounds 20, 21
Scheme 7 Synthesis of compounds 27—29
Scheme 5 Synthesis of compounds 22, 23
sites from 6 to 4 and the number of matching active
ligands from 14 ligands to 9 ligands. Initially, number
of sites was varied from 6 to 4 until at least one hy-
pothesis was found and scored successfully. If this
failed, then number of active ligands was decreased by
one and the number of sites cycle repeated (Table 1).
Pharmacophore with five features common to all ac-
tive ligands were identified then scored according to
superposition of pharmacophore site, alignment of vec-
tor characteristics, and penalization of matches to inac-
tive training set molecules.
The scoring procedure for all the hypotheses pro-
vided a ranking of the different hypotheses, thereby al-
lowing to make rational choices about hypotheses.
The top scoring hypotheses from each pharmacophore
sites were selected and used for further validation.
The top scoring hypotheses were processed to search
a database of literature reported compounds for struc-
tures that match the hypotheses. The best pharma-
cophore hypothesis was selected based on number of
active compounds retrieved from a database. It was
found that the best pharmacophore hypothesis was
ADHRR (Figure 1) having maximum active ratio.
The various substitutions were then made on
N-(3-arylpropyl)-9,10-dihydro-9-oxoacridine-4-carbox-
amide nucleus by maintaining the required pharmaco-
amides, the title compounds with 3-phenoxy substitu-
tion exhibited better activity.
Experimental
Pharmacophore drug designing
A five point pharmacophore generation was devel-
oped by using fourteen active ligands belonging to
9,10-dihydro-9-oxoacridine-4-carboxamide class.9 All
the ligands were first processed with the LigPrep soft-
ware program to assign protonation states, generate
stereoisomers and convert 2D to 3D structures. Con-
former generation was carried out with the MacroModel
ligand torsion search with OPLS_2005 force field.
Pharmacophore hypotheses were generated by a
systematic variation of the number of pharmacophore
506
www.cjc.wiley-vch.de
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2011, 29, 504— 510

N-(3-Arylpropyl)-9,10-dihydro-9-oxoacridine-4-carboxamides as Potent MDR Reversal Agents
Table 1 Number of pharmacophore sites and ligands that
matches the top scoring hypothesesa
Number of
Number of
matching ac- number of
tive ligamds hypotheses
Maximum
pharma-
cophore
sites
Top scoring Score
hypotheses actives
14
No hypothesis —
—
—
13
12
11
No hypothesis —
6
5
2
2
ADRRRR 4.697
ADHRRR 4.502
14
13
12
11
10
9
No hypothesis —
No hypothesis —
—
—
Figure 1 The top scoring Pharmacophore hypothesis ADHRR
(A4 is acceptor point, D6 is donor point, H8 is hydrophobic point,
R12 and R13 are aromatic points).
2
2
2
2
ADHRR
4.516
4.516
4.506
4.131
ADHRR
ADHRR
ADHPR
14
13
12
11
10
9
No hypothesis —
No hypothesis —
—
—
2
2
2
2
AADR
5.355
3.267
3.220
3.142
4
AARR
AARR
AARR
a A＝acceptor point, D＝donor point, H＝hydrophobic point, R
Figure 2 N-(3-Arylpropyl)-9,10-dihydro-9-oxoacridine-4-car-
boxamide analogue overlaid with the best Pharmacophore hy-
pothesis ADHRR.
＝aromatic point, P＝positive point.
phoric features.
The N-(3-arylpropyl)-9,10-dihydro-9-oxoacridine-4-
carboxamide analogues overlaid onto the best pharma-
cophore hypothesis ADHRR (Figure 2). All the ten
analogues exhibited good alignment with reference
ligand.
The designing study was performed using phase
drug designing software (SCHRODINGER, INC) on
INTEL CORE 2 Duo 2 GHz computer.
cooled to 20—25 ℃. The mixture was poured into wa-
ter and acidified with conc. HCl. The precipitate formed
was filtered and washed with water. The crude product
was then dissolved in aqueous sodium hydroxide solu-
tion, treated with activated charcoal, boiled and filtered.
The filtrate was acidified with conc. HCl to obtain the
precipitate of crude product which was collected by fil-
tration. The crude product was purified by recrystalliza-
tion using ethanol (17.2 g, 64.7%, m.p. 254 ℃).
Analysis
Melting points of the synthesized molecules were
determined by open capillary tube and were uncorrected.
The purity of the compounds was ascertained by thin
layer chromatography (TLC) on pre-coated silica gel G
plate. I.R. spectra were recorded on Jasco FT/IR-5300
spectrometer using KBr pellet method. Nuclear mag-
netic resonance spectra were recorded using Joel
FT/NMR 300 MHz spectrometer using TMS as an in-
ternal standard. Mass spectroscopy was carried out on
Q-Tof micro (YA-105), Micromass (Water’s) mass
spectrometer. Elemental analysis was performed using
EA-112, Thermoquest CHN analyzer. All the title
compounds were purified by silica gel column chroma-
tography.
Synthesis of 9,10-dihydro-9-oxoacridine-4-carboxylic
acid (4)
A mixture of 2,2'-iminobisbenzoic acid 3 (15 g,
0.058 mol) and conc. sulfuric acid 48 ml was heated at
100 ℃ for 4 h, cooled at room temperature and then
poured into ice water. The precipitate formed was col-
lected and washed with water. The crude product was
purified by recrystallization using ethanol (9.27 g,
55.1%, m.p. 325 ℃).
Synthesis of 9,10-dihydro-9-oxoacridine-4-carbon-
yl chloride (5)
A suspension of 9,10-dihydro-9-oxoacridine-4-
carboxylic acid 4 (15 g, 0.066 mol) in 45 mL thionyl
chloride containing DMF (4 drops) was heated gently
under reflux for 2 h. The solution was evaporated to
dryness in vacuum. The crude product was collected,
washed with benzene and purified by recrystallization
using ethanol (10.2 g, 63%, m.p. 314 ℃).
Synthesis of 2,2'-iminobisbenzoic acid (3)
A suspension of o-bromobenzoic acid (17.1 g, 0.085
mol), anthranilic acid (17.1 g, 0.124 mol), 0.3 g copper
powder and 16.4 g of potassium carbonate in 80 mL of
ethanol was heated to reflux for 6 h. The suspension was
Chin. J. Chem. 2011, 29, 504— 510
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
507

Velingkar & Dandekar
FULL PAPER
Synthesis of 3-chloro-1-phenyl-1-propanol (7)
also be prepared with similar method using N-methyl-3-
chloro-3-phenyl propylamine and phenol (7 g, 56.6%,
m.p. 128 ℃). N-Methyl-3-phenyl-3-(2'-methyl phenoxy)
propylamine (16) could also be prepared with similar
method using N-methyl-3-chloro-3-phenyl propylamine
and o-cresol (11.4 g, 54.9%, m.p. 174 ℃).
To a solution of 3-chloropropriophinone (15 g, 0.09
mol) in 50 mL methanol, sodium borohydride (6.12 g,
0.162 mol) was added in small portions with constant
stirring at room temperature over a period of 40 min.
Methanol was removed under vacuum and the reaction
mixture was diluted with 100 mL of ether, washed twice
with water and dried over anhydrous magnesium sulfate.
Concentration to dryness yielded 3-chloro-1-phenyl-1-
propanol. The crude product was purified by recrystal-
lization using ethanol (12.36 g, 83%, m.p. 56 ℃).
Synthesis of 3-substituted-N-methyl-3-phenylpropyl-
amine (9, 18)
General procedure A mixture of suitable
3-iodo-1-phenyl-1-substituted propyl derivatives (15 g,
0.057 mol), 40% methylamine solution (48 mL, 0.57
mol) and 105 mL of tetrahydrofuran was stirred at room
temperature overnight. The solvent was then removed
under reduced pressure and the mixture was made alka-
line with sodium hydroxide solution with cooling. The
mixture was then extracted with ether. The combined
ether extracts were dried over anhydrous magnesium
sulfate and the ether layer was evaporated to give 3-
substituted-N-methyl-3-phenylpropylamine (9, 18).
3-Substituted-3-phenylpropylamine (10, 19) could
also be prepared with the similar procedure using am-
monia solution.
Synthesis of 3-iodo-1-phenyl-1-propanol (8)
A solution of 3-chloro-1-phenyl-1-propanol (15 g,
0.087 mol) in 150 mL of acetone that had been saturated
with anhydrous sodium iodide was refluxed for 12 h.
The acetone was removed under vacuum; the reaction
mixture was diluted with 75 mL water and extracted
twice with ether. The organic layer was separated and
washed with water, dried over anhydrous sodium sulfate
and ether was evaporated to produce 3-iodo-1-phenyl-1-
propanol as light red oil (17.4 g, 75.5%).
Synthesis of N-methyl-3-chloro-3-phenyl propyl-
amine (11)
Synthesis of 3-iodopropiophenone (17)
A saturated solution of anhydrous sodium iodide in
300 mL of anhydrous acetone was refluxed on water
bath for 1 h. To this mixture 3-chloropropiophenone (30
g, 1.914 mol) was added and refluxed for 10 h. The
mixture was cooled at room temperature and filtered.
The acetone was removed under vacuum; the reaction
mixture was diluted with water and extracted twice with
ether. The organic layer was separated and washed with
water, dried over anhydrous sodium sulfate and finally
ether layer was evaporated to obtain 3-iodopropiophen-
one. The crude product was purified by recrystallization
using n-hexane (29.4 g, 63.5%, m.p. 60 ℃).
To a cold solution of freshly distilled thionyl chlo-
ride (15.6 mL, 0.21 mol) in 60 mL of dry chloroform,
N-methyl-3-hydroxy-3-phenyl propylamine (27 g, 0.162
mol) was added over a period of 1 h at a rate that tem-
perature did not exceed 25 ℃. After addition, the mix-
ture was heated at 50—60 ℃ for 4 h, and then concen-
trated to dryness. The reaction mixture was extracted
twice with 20 mL of ether and washed with water. The
organic layer was separated, dried over anhydrous so-
dium sulfate and evaporated to obtain N-methyl-3-
chloro-3-phenyl propylamine (19.2 g, 63.9%).
Synthesis of 3-chloro-3-phenylpropylamine (12)
could also be prepared with similar method using
3-hydroxy-3-phenyl propylamine (20.1 g, 66.3%).
Synthesis of 9,10-dihydro-9-oxo-N-(3-substituted-3-
phenylpropyl)acridine-4-carboxamide (20— 21, 27—
29)
Synthesis of 3-phenyl-3-phenoxy propylamine (13)
General procedure 9,10-Dihydro-9-oxoacridine-
4-carboxylic acid (8.05 g, 0.035 mol) was dissolved in
35 mL DMF in RBF with guard tube attached at the
neck and stirred for 30 min in cold condition. DCC
(7.25 g, 0.035 mol) was dissolved separately in 35 mL
DMF in a beaker and was then added dropwise to a so-
lution of 9,10-dihydro-9-oxoacridine-4-carboxylic acid
and stirred for 2 h in cold condition. 3-Substituted-3-
phenyl-propylamine derivative (0.74 g, 0.005 mol) was
dissolved in 50 mL DMF in a beaker and stirred for 1 h
in cold condition. This solution was then added to the
above mixture and stirred continuously for 4 h in cold
condition and overnight at room temperature. The reac-
tion mixture was further filtered; the filtrate was then
concentrated under vacuum and extracted with ethy-
lacetate. The organic layer was washed with water and
evaporated to give a residue that was finally purified by
column chromatography. Table 2 depicts the physical
data of these compounds.
A mixture of phenol (9 g, 0.095 mol) and powdered
sodium hydroxide (5 g, 0.12 mol) in 40 mL ethanol was
refluxed for 30 min. A solution of 3-chloro-3-phenyl
propylamine (12) (10 g, 0.058 mol) in 40 mL ethanol
was added to it. After complete addition, the mixture
was refluxed on a water bath for 4.5 h. Ethanol was re-
moved under reduced pressure. The reaction mixture
was washed thoroughly with 50 mL of 10% sodium hy-
droxide solution and then extracted with 50 mL ether.
The ether layer was washed successively with 40 mL of
10% sodium hydroxide solution and three portions of
water. Ether layer was then dried over anhydrous so-
dium sulfate. Evaporation of ether layer yielded
3-phenyl-3-phenoxy propylamine (7.2 g, 54.2%).
3-Phenyl-3-(2'-methyl phenoxy) propylamine (14) could
also be prepared with similar method using 3-chloro-
3-phenyl propylamine and o-cresol (11.4 g, 53.6%).
N-Methyl-3-phenyl-3-phenoxy propylamine (15) could
508
www.cjc.wiley-vch.de
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2011, 29, 504— 510

N-(3-Arylpropyl)-9,10-dihydro-9-oxoacridine-4-carboxamides as Potent MDR Reversal Agents
8.38 (m, 17H, Ar); IR (KBr) ν: 3382 (C—H), 1638 (C＝
Table 2 Physical data of title compounds
O), 1594 (C＝O), 1532 (NH), 1204, 1016＋(C—O), 1016
Compound
Yield/%
40
m.p./℃
－1
(C—N) cm ; ESMS m/z: 461.7684 [M] . Anal. calcd
20
21
22
23
24
25
26
27
28
29
168
142
172
158
176
186
158
182
138
146
for C30H26N2O3: C 77.90, H 5.67, N 6.06; found C 77.82,
H 5.63, N 6.02.
45
9,10-Dihydro-N-methyl-N-[3-(2-methylphenoxy)-
3-phenylpropyl]-9-oxoacridine-4-carboxamide (23)
1H NMR (CDCl3, 300 MHz) δ: 2.22 (q, J＝7.2 Hz, 2H,
CH2), 2.44 (s, 3H, CH3), 2.85 (s, 3H, CH3), 3.21 (t, J＝
5.4 Hz, 2H, CH2), 5.08 (t, J＝7.8 Hz, 1H, CH), 7.36 (s,
1H, NH), 6.67—8.42 (m, 16H, Ar); IR (KBr) ν: 3292 (C
—H), 1652 (C＝O), 1594 (C＝O), 1504 (NH), 1088,
42
45
42
40
40
40
－1
1208 (C—O), 1088 (C—N) cm ; ESMS m/z: 475.9981
41
[M]＋. Anal. calcd for C31H28N2O3: C 78.13, H 5.92, N
5.88; found C 78.08, H 5.88, N 5.78.
40
9,10-Dihydro-N-(3-hydroxy-3-phenylpropyl)-N-
methyl-9-oxoacridine-4-carboxamide (24) 1H NMR
(CDCl3, 300 MHz) δ: 2.01 (q, J＝7.2 Hz, 3H, CH2 and
OH), 2.84 (s, 3H, CH3), 3.41 (t, J＝6.4 Hz, 2H, CH2),
3.82 (q, J＝7.8 Hz, 1H, CH), 7.21 (s, 1H, NH), 6.64—
8.22 (m, 12H, Ar); IR (KBr) ν: 3406 (OH), 2906 (C—
H), 1684 (NH), 1685 (C＝O), 1618 (C＝O), 1094 (C—
Synthesis of 9,10-dihydro-N-(3-substituted-3-phenyl-
propyl)-N-methyl-9-oxoacridine-4-carboxamide
(22— 26)
General procedure A mixture of 9,10-dihydro-9-
oxoacridine-4-carbonyl chloride (7.74 g, 0.030 mol),
3-substituted-N-methyl-3-phenylpropylamine (5 g,
0.030 mol) derivative and anhydrous potassium carbon-
ate (1.4 g) in 50 mL of DMF was heated at 70 ℃ with
stirring for 5 h. To the mixture, 50 mL ice-cold water
was added and extracted with ethylacetate. The organic
layer was washed and evaporated to give a residue that
was purified by column chromatography. Table 2 de-
picts the physical data of these compounds.
＋
－1
N) cm ; ESMS m/z: 386.1143 [M] . Anal. calcd for
C24H22N2O3: C 74.59, H 5.74, N 7.25; found C 74.48, H
5.68, N 7.18.
9,10-Dihydro-N-methyl-9-oxo-N-(3-oxo-3-phenyl-
propyl)acridine-4-carboxamide (25)
1H NMR
(CDCl3, 300 MHz) δ: 2.61 (t, J＝6.8 Hz, 2H, CH2), 2.88
(s, 3H, CH3), 3.51 (t, J＝6.4 Hz, 2H, CH2), 7.49 (s, 1H,
NH) 7.16—8.31 (m, 12H, Ar); IR (KBr) ν: 2934 (CH),
1696 (C＝O), 16－82 (NH), 1588 (C＝O), 1526＋(C＝O),
9,10-Dihydro-9-oxoacridine-4-carboxylic acid (4)
1H NMR (DMSO-d6, 300 MHz) δ: 7.41—7.89 (m, 7H,
Ar), 7.54 (s, 1H, NH), 10.80 (s, 1H, COOH); IR (KBr) ν:
3331 (NH), 2964 (CH),－2883 (OH), 1666 (C＝O), 1618
1
1056 (C—N) cm ; ESMS m/z: 385.0602 [MH ]. Anal.
calcd for C24H20N2O3: C 74.98, H 5.24, N 7.29; found C
74.72, H 5.22, N 7.21.
1
(C＝O), 1579 (NH) cm ; ESMS m/z: 240.1171
[MH＋]. Anal. calcd for C29H24N2O3: C 70.29, H 3.79, N
5.85; found C 70.18, H 3.58, N 5.64.
N-(3-Chloro-3-phenylpropyl)-9,10-dihydro-N-
methyl-9-oxoacridine-4-carboxamide (26) 1H NMR
(CDCl3, 300 MHz) δ: 2.14 (q, J＝7.2 Hz, 2H, CH2),
2.91 (s, 3H, CH3), 3.52 (t, J＝5.4 Hz, 2H, CH2), 3.84 (t,
J＝6.4 Hz, 1H, CH), 7.33 (s, 1H, NH), 6.62—8.42 (m,
12 H, Ar); IR (KBr) ν: 2962 (CH), 1672 (C＝O), 16－56
9,10-Dihydro-9-oxo-N-(3-phenoxy-3-phenylpro-
pyl)acridine-4-carboxamide (20) 1H NMR (CDCl3,
300 MHz) δ: 2.34 (q, J＝7.4 Hz, 2H, CH2), 3.38 (t,
J＝6.2 Hz, 2H, CH2), 4.68 (t, J＝8.0 Hz, 1H, CH), 7.40
(s, 1H, NH), 6.24—8.40 (m, 17H, Ar); IR (KBr) ν: 3334
(NH), 2998 (CH), 1688 (C＝O), 1596 (C＝O), 1448
1
(C＝O), 1518 (NH), 1032＋(C—N), 704 (C—Cl) cm ;
ESMS m/z: 403.0422 [M] . Anal. calcd for C24H21Cl-
N2O2: C 71.19, H 5.23, N 6.92; found C 71.11, H 5.19,
N 6.84.
－1
(NH), 1268, 1106 (C—O) cm ; ESMS m/z: 448.1521
[M]＋. Anal. calcd for C29H24N2O3: C 77.66, H 5.39, N
6.25; found C 77.52, H 5.35, N 6.20.
9,10-Dihydro-N-(3-hydroxy-3-phenylpropyl)-9-
oxoacridine-4-carboxamide (27) 1H NMR (CDCl3,
300 MHz) δ: 2.01 (q, J＝7.8 Hz, 3H, CH2 and OH),
3.36 (t, J＝6.0 Hz, 2H, CH2), 3.78 (q, J＝7.2 Hz, 1H,
CH), 5.25 (s, 1H, NH), 7.52 (s, 1H, NH), 7.16—8.42 (m,
12H, Ar); IR (KBr) ν: 3494 (NH), 3396 (CH), 30－02
9,10-Dihydro-N-[3-(2-methylphenoxy)-3-phenyl-
propyl]-9-oxoacridine-4-carboxamide (21) 1H NMR
(CDCl3, 300 MHz) δ: 2.31 (s, 3H, CH3), 2.26 (q, J＝7.2
Hz, 2H, CH2), 3.36 (t, J＝5.8 Hz, 2H, CH2), 4.48 (t,
J＝8.2 Hz, 1H, CH), 7.30 (s, 1H, NH), 6.32—8.39 (m,
16H, Ar); IR (KBr) ν: 3474 (NH), 3394 (CH), 1626 (C
＝O),1554 (C＝O), 1462 (NH), 1＋310, 1202 (C—O)
1
(OH), 1688 (C＝O), 162＋2 (C＝O), 1582 (NH) cm ;
ESMS m/z: 372.1498 [M] . Anal. calcd for C23H20N2O3:
C 74.18, H 5.41, N 7.52; found C 74.12, H 5.23, N 7.42.
9,10-Dihydro-9-oxo-N-(3-oxo-3-phenylpropyl)ac-
ridine-4-carboxamide (28) 1H NMR (CDCl3, 300
MHz) δ: 2.75 (t, J＝6.8 Hz, 2H, CH2), 3.83 (t, J＝6.0
Hz, 2H, CH2), 5.49 (s, 1H, NH), 7.52 (s, 1H, NH), 6.51
—8.15 (m, 12H, Ar); IR (KBr) ν: 3356 (NH), 29－21
－ 1
cm ; ESMS m/z: 461.9865 [M] . Anal. calcd for
C30H26N2O3: C 77.90, H 5.67, N 6.06; found C 77.86, H
5.54, N 6.01.
9,10-Dihydro-N-methyl-9-oxo-N-(3-phenoxy-3-
phenylpropyl)acridine-4-carboxamide (22)
1H
NMR (CDCl3, 300 MHz) δ: 2.32 (q, J＝7.8 Hz, 2H,
CH2), 2.67 (s, 3H, CH3), 3.28 (t, J＝6.0 Hz, 2H, CH2),
4.74 (t, J＝8.4 Hz,1H, CH), 7.38 (s, 1H, NH), 6.70—
1
(CH), 1694 (C＝O), 168＋2 (C＝O), 1628 (NH) cm ;
ESMS m/z: 370.1648 [M] . Anal. calcd for C23H18N2O3:
Chin. J. Chem. 2011, 29, 504— 510
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
509

Velingkar & Dandekar
FULL PAPER
C 74.58, H 4.90, N 7.56; found C 74.52, H 4.78, N 7.53.
N-(3-Chloro-3-phenylpropyl)-9,10-dihydro-9-oxo-
acridine-4-carboxamide (29) 1H NMR (CDCl3, 300
MHz) δ: 2.11 (q, J＝7.2 Hz, 2H, CH2), 3.42 (t, J＝5.4
Hz, 2H, CH2), 3.67 (t, J＝7.4 Hz, 1H, CH), 5.12 (s, 1H,
NH), 7.35 (s, 1H, NH), 6.69—8.03 (m, 12H, Ar); IR
(KBr) ν: 3412 (NH), 3324 (CH), 1686 (－C＝O), 1672 (C
＝O), 1624 (NH), 754 (C—Cl) cm 1; ESMS m/z:
390.2144 [M]＋. Anal. calcd for C23H19 ClN2O2: C 70.68,
H 4.90, N 7.17; found C 70.67, H 4.78, N 7.14.
Table 3 PIC50 values of title compounds by standard Hoechst
33342 assay method
Compound No.
PIC50±SD
20
5.70±0.16
5.48±0.14
5.28±0.16
5.12±0.09
4.22±0.18
4.34±0.16
4.32±0.07
4.28±0.06
4.66±0.18
4.35±0.23
5.18±0.25
21
22
23
24
25
26
Pharmacological evaluation
27
28
The title compounds 20—29 were screened to evalu-
ate their inhibitory effects on the transport activity of
P-glycoprotein (P-gp) by standard Hoechst 33342 assay
method.12
29
Verapamil
Human ovarian carcinoma cell lines A2780 were
cultivated in RPMI-1640 medium supplemented with
10% fetal bovine serum, 50 µg/mL streptomycin, 50
U/mL penicillin G, and 365 µg/mL L-glutamine. Cells
were grown to 80%—90% confluence and treated with
trypsin-EDTA before subculturing. Every 5th passage
doxorubicin (0.1 µmol/L final concentration) was added
to the cell culture medium of A2780adr cells to main-
tain a resistance pressure and to conserve P-gp overex-
pression.
signed molecules were synthesized by a novel synthesis
route and characterized by spectroscopic techniques like
I.R., 1H NMR, Mass and elemental analysis.
The screening of inhibitory effects on the transport
activity of P-glycoprotein (P-gp) showed that among
substituted N-(3-arylpropyl)-9,10-dihydro-9-oxoacri-
dine-4-carboxamides, the title compounds with
3-phenoxy substitution exhibited better activity.
Human ovarian carcinoma cell lines A2780 and the
corresponding adriamycin-resistant A2780adr cell line
were grown in T75 or T175-flasks. At a confluence of
approximately 80% cells were harvested by trypsination.
Pelleted cells were resuspended in fresh culture medium
and counted with a Casy I Modell TT cell counter. After
three washing steps with Krebs-Hepes buffer, cells were
seeded into black 96 well plates at a density of ap-
proximately 30000 cells in a volume of 90 µL per well.
Then, 10 µL of various title compounds in different
concentrations were added, resulting in a final volume
of 100 µL per well. The prepared 96-well plates were
kept under 5% CO2 at 37 ℃ for 30 min. After this
preincubation period, 20 µL of a 30 µmol/L Hoechst
33342 solution were added to each well. Subsequently,
fluorescence was measured immediately at constant
time intervals (120 s) up to 46 min at an excitation
wavelength of 365 nm and an emission wavelength of
450 nm using a 37 ℃ tempered BMG POLARstar mi-
croplate reader. The inhibitory effect of P-gp is ex-
pressed in terms of PIC50 value (Table 3).
Acknowledgements
The authors are thankful to Prin. K. M. Kundnani
College of Pharmacy, Mumbai for providing the infra-
structure and facilities. The authors are also thankful to
All India Council for Technical Education (AICTE) for
the financial support.
The authors are grateful to Institute of Pharmacy,
University of Bonn, Germany for Biological evaluation.
References
1
2
Krishna, R.; Mayer, L. D. Eur. J. Pharm. Sci. 2000, 11, 265.
Ferry, D. R.; Traunecker, H.; Kerr, D. J. Eur. J. Cancer
1996, 32A, 1070.
3
4
5
Ford, J. M.; Hait, W. N. Pharmacol. Rev. 1990, 42,155.
Thomas, H.; Coley, H. M. Cancer Control 2003, 10,159.
Wandel, C.; Kim, R. B.; Kajiji, S. Cancer Res. 1999, 59,
3944.
6
7
8
9
Twentyman, P. R.; Bleehen, N. M. Eur. J. Cancer 1991, 27,
1639.
Dantzig, A. H.; Shepard, R. L.; Law, K. L. J. Pharmacol.
Exp. Ther. 1999, 290, 854.
Roe, M.; Folkes, A.; Ashworth, P. Bioorg. Med. Chem. Lett.
1999, 9, 595.
Dodic, N.; Dumaitre, B.; Daugan, A.; Pianetti, P. J. Med.
Chem.1995, 38, 2418.
Conclusion
In the present work, potent novel analogs of
N-(3-arylpropyl)-9,10-dihydro-9-oxoacridine-4-carbox-
amides have been developed by pharmacophore drug
designing, organic synthesis and standard Hoechst
33342 assay method, which have shown the
encouraging results.
The basic nucleus, N-(3-arylpropyl)-9,10-dihydro-
9-oxoacridine-4-carboxamides was designed using the
five point pharmacophore hypothesis ADHRR. The de-
10 Joshi, J. K.; Patel, V. R.; Patel, K.; Rana, D.; Shah, K.; Patel,
R. Ind. J. Pharm. Sci. 2007, 69, 697.
11 Atwell, G. J.; Cain, B. F.; Baguley, B. C.; Finlay, G. J.;
Denny, W. A. J. Med. Chem. 1984, 27, 1481.
12 Muller, H.; Pajeva, I. K.; Globischa, C.; Wiese, M. Bioorg.
Med. Chem. 2008, 16, 2456.
(E1006246 Lu, Y.)
510
www.cjc.wiley-vch.de
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2011, 29, 504— 510