J. Chil. Chem. Soc., 57, Nº 2 (2012)
NMR (CDCl ): 14.3, 61.1, 106.35, 116.0, 121.1, 122.9, 126.9, 128.1, 128.6,
130.9, 135.4,3139.9, 149.5, 154.1, 163.0, 173.1, 179.1. HRMS (EI) m/z calcd
for C19H13NO4: 319.08446; found: 319.084335.
Ethyl
6,11-dioxo-6,11-dihydrobenzo[f]pyrido[1,2-a]indole-12-
carboxylate (2): Orange solid, mp 158.9-159.3 ºC; IR (KBr, vmax cm-1): 1694,
1
1673, 1473, 1250, 713. H RMN(CDCl3): 9.82 (dt, 1H, 4, J=6.97 Hz), 8.29
(td, 1H, 1, J=9.11 Hz), 8.20 (m, 2H, 7,10), 7,70 (m, 2H, 8,9), 7,41 (t, 1H, 2,
J= 6.84Hz), 7,16 (t, 1H, 3, J=6.96Hz), 4.51 (q, 2H, CH2, J= 7,14 Hz), 1.50
(t, 3H, CH , J= 7,13 Hz); 13C NMR (CDCl3): 14.3, 61.0, 106.0, 117.3, 120.9,
122.4, 1253.9, 127.2, 127.7, 128.2, 128,6, 133.1, 133.4, 133.7, 134.1, 139.5,
163.2, 175.1, 180.1. HRMS (EI) m/z calcd for C18H12N2O4: 320.0797; found:
320.079413.
Ethyl
5,12-dioxo-5,12-dihydroindolizino[3,2-g]quinoline-11-
carboxylate (3): Orange solid, mp 232-233ºC; IR 1673 (KBr, vmax cm-1):
1
1675,1637, 1488, 1383, 1318; H RMN(CDCl3): 9.08 (dt, 1H, J=7.00, 1.11
Hz), 9.00 (dd,1H, J= 4.67, 1.75 Hz), 8.56 (dd, 1H, J= 7,87, 1.75), 8.39 (dt, 1H,
J= 9.10, 1.21 Hz), 7,65 (dd, 1H, J= 4,67 Hz), 7,48 (m 1H), 7.21 (td, 1H, J=
6.84, 1.33 Hz), 4.50 (q, 2H, CH2, J= 7,16 Hz), 1.51 (t, 3H, CH3, J= 7,13 Hz);
13C NMR (CDCl3): 14.1, 61.2, 106.1, 117.9, 121.4, 126.8, 127.1, 128.2, 128.4,
130.6, 134.3, 150.5, 153.6, 163.4, 173.73, 177.6. HRMS (EI) m/z calcd for
C18H12N2O4: 320.0797; found: 320.079331.
12-acetylbenzo[f]pyrido[1,2-a]indole-6,11-dione (4): Red solid,
mp 207.7-208.3 ºC; IR (KBr, v cm-1); 1666, 1637, 1493, 1232, 712. H
1
RMN(CDCl3): 9.08 (dt, 1H, 2, J=m7a.x02 Hz), 8.3 (td, 1H, 5, J=9.11 Hz), 8.2 (m,
2H, 14,17), 7,7 (m, 2H, 15,16), 7,4 (t, 1H, 4, J= 5,6Hz), 7,2 (t, 1H, 5, J=5,6
Hz); 13C NMR (CDCl3): 31.9, 61.0, 114.6, 117.9, 121.6, 126.1, 126.2, 127.1,
127.5, 128.0, 128.7, 133.1, 133.6, 139.3, 175.1, 181.9, 197.1. HRMS (EI) m/z
calcd for C18H11NO3 289.0739; found: 289.072456.
Figure 2, Correlation tendency between half-wave redox potentials and
IC50,¯ Normal MRC-5, ¢ AGS, SK-MES-1, r J82 cell lines.
As conclusion of our work it was possible to establish some structure
activity relationships of indolizino [1,2-b] quinoline derivatives, emphasizing
that the presence of a nitrogen atom in ring A plays an important role regarding
the potency and selectivity on cancer cell lines. Also, it was possible to establish
the mode of action of the substrates studied using tendency correlations
between the half-wave redox potential and measured biological activities.
Then, the combination of an indole ring analogue with a quinone must generate
a largely conjugated system that may undergo electronic transfer processes,
because these rings have a very rigid and coplanar conformation. Therefore,
modification with different substituents at some position in the indole ring, or in
the quinone system, must originate a new family of indolequinones which will
differ in their electrodic processes, seeking to improve their redox mediating
capacities. Specific studies on the interaction of analogues with DNA nucleic
acids will be also accomplished.
6-acetylindolizino[2,3-g]quinoline-5,12-dione (5): Red solid, mp 250-
251 ºC; IR (KBr, vmax cm-1): 2962, 1642, 1491, 1367, 1312; 1H RMN(DMSO-d6):
9.69 (d, 1H, 4, J=7.04 Hz), 8.95 (d, 1H, 1, J=9.11 Hz), 8.51 (dd, 1H, J= 8.06
Hz), 8.30 (dd, 1H, 2, J= 7.52Hz), 8.00 (m, 2H, 3), 7.76 (t, 1H, , J= 7,40 Hz),
2.39 (s, 3H, CH3). HRMS (EI) m/z calcd for C17H10N2O3 290.06914; found:
290.068753.
6,11-dioxo-6,11-dihydrobenzo[f]pyrido[1,2-a]indole-12-carbonitrile
(6): Red solid, mp 290.9-292.4 ºC; IR (KBr, vmax cm-1); 2221, 1669, 1642,
1
1509, 1230; H RMN(CDCl ): 7.5(t, 1H, 3, J=6.08 Hz), 7.8 (m, 2H, 15,16),
7.9 (dt, 1H,4, J=8.99 Hz), 83.3 (m, 3H, 14,17, 5), 9.8 (dd, 1H, 2, J= 6.1Hz);
13C NMR (CDCl3): 94.5, 97.2, 120.4, 120.8, 121.5, 123.3, 126.0, 126.7, 132.1,
133.7, 133.9, 134.5, 135.1, 135.8, 150.0, 172.8, 180.0. HRMS (EI) m/z calcd
for C17H8N O2: 272.05858; found: 272.058102.
5,12-d2ioxo-5,12-dihydroindolizino[2,3-g]quinoline-6-carbonitrile (7):
Orange solid, mp 290-292 ºC; IR (KBr, vmax cm-1); 2223, 1657, 1644, 1511,
1230; 1H RMN(DMSO-d6): 9.51 (d, 1H, 4, J=6.92 Hz), 8.91 (dd, 1H, 1, J=4.8,
1.5 Hz), 8.48 (dd, 1H, J= 7.8, 1.5 Hz), 7,91 (d, 1H, J= 9.0 Hz), 7,78 (dd, 1H, J=
7.8, 4.8 Hz), 7,40 (td, 1H, J=6.9, 1,2Hz), 7.28 (td, 1H, J= 6.9, 0.9 Hz). HRMS
(EI) m/z calcd for C17H9N3O2: 273.5383; found: 273.531502.
EXPERIMENTAL
1H and 13C NMR spectra were obtained on AM-400 instruments, using
tetramethylsilane as internal reference, using CDCl3 and DMSO-d solutions.
EI-MS experiments were performed on a MAT 95XP Thermo6-Finnigann
spectrometer. The accurate mass measurements were performed at
a
resolution of 9000-10000 (10% valley definition) by voltage scanning using
perfluorokerosene (PFK) as the reference compound. IR spectra (4000–250
cm-1) were recorded with samples as KBr pellets on a Bruker Model Vector 22
spectrophotometer. Electrochemical measurements were performed on a CHI
Instruments Model 900B potentiostat using a conventional three-electrode
cell. Platinum and platinum wires were used as working and counter electrode,
respectively. All potentials quoted in this work are refered to an Ag/AgCl, KCl
(sat’d) reference electrode (0.197 V vs. NHE). Column chromatography was
performed on silica gel Merck 60 (70–230 mesh). All reagents used were of
analytical reagent grade from Sigma Chemical Co.(St Louis, MO, U.S.A) and
melting points were determined on the Stuart Scientific SMP3 apparatus.
General procedures
6,11-dioxo-6,11-dihydrobenzo[f]pyrido[1,2-a]indole-12-carboxylic
acid (8): To a 100 mL round bottom flask it was added 0.5 g (2.2 mmol) of
2,3-dichloronaphthalene-1,4-dione, 2.2 mmol of 2,2-dimethyl-1,3-dioxane-
4,6-dione and 22 eq. of pyridine in 30 of ethanol (solvent). The suspension was
agitated by 6 hours; the purple precipitated was filtered and was washed with
water gently. The yield was 95%. Purple solid, mp 304.5-304.9ºC; IR (KBr,
vmax cm-1): 3422, 1645, 1584, 1233, 715. 1H RMN(DMSO-d6): 9.77 (d, 1H, 4,
J= 5.70 Hz), 9.45 (t, 1H,1, J=7.82 Hz), 8.97 (t, 2H, 8,9, J= 6.95 Hz), 8.87 (m,
2H, 15,16), 8.72 (m, 2H, 2,3). HRMS (EI) m/z calcd for C17H9NO4: 291.05316;
found: 291.0528411.
Antiproliferative activity
All human cell lines used in this work were purchased from the American
Type Culture Collection (ATCC, Manasas, VA, USA). Normal lung fibroblasts
(MRC-5), lung cancer cells (SK-MES-1) and bladder carcinoma cells (J82)
were grown as monolayers in minimum essential Eagle medium (MEM) with
Earles´s salts, 2 mM L-glutamine and 1.5 g/l sodium bicarbonate, supplemented
with 10% heat-inactivated fetal bovine serum (FBS), 100 IU/ml penicillin and
100 µg/ml streptomycin. Gastric epithelial cells AGS (CRL-1739) were grown
as monolayers in Ham F-12 medium containing 1 mM L-glutamine and 1.5 g/l
sodium bicarbonate, supplemented with 10% heat-inactivated FBS, 100 IU/ml
penicillin and 100 µg/ml streptomycin. All cell lines were grown as monolayers
in a humidified incubator with 5% CO2 in air at 37°C. For the antiproliferative
assay, cells were plated at a density of 5 x 104 cells/mL in 96-well plates (100
µL/well). One day after seeding, cells were treated with medium containing
the compounds at concentrations ranging from 0 up to 100 µM during 3 days.
The compounds were dissolved in DMSO (1% final concentration). Untreated
The quinoline´s compounds 1-7, were synthesized accord to reference [6],
with exception of carboxylic acid compound.
To
a 100 mL round bottom flask it was added 2.2 mmol of
2,3-dichloronaphthalene-1,4-dione, 2.6 mmol of aceto acetil derivative, 26
mmol of pyridine in 30 mL of ethanol. The suspension was reflux by 6 hours;
the precipitated was filtered and was washed with water gently. The precipited
formed was subsequently subjected to flash column chromatography packed
manually with silica gel to give the corresponding target compound.
Ethyl
5,12-dioxo-5,12-dihydroindolizino[2,3-g]quinoline-6-
carboxylate (1): Orange solid, mp 227-228 ºC; IR (KBr, vmax cm-1): 1678,
1
1641, 1571, 1487, 1383. H RMN(CDCl3): 9.94 (d, 1H, 4, J=7.00 Hz), 9.01
(dd, 1H, 1, J=4.68, 1.73 Hz), 8.54 (dd, 1H, J=7.89, 1.76 Hz), 8.35 (dt, 1H, J=
9.11, ), 7,63 (dd, 1H, J= 7.90, 4.70 Hz), 7,48 (t, 1H, J=7.39 Hz), 7.23 (t, 1H,
J= 7.68 Hz) 4.52 (q, 2H, CH2, J= 7,12 Hz), 1.49 (t, 3H, CH3, J= 7,15 Hz); 13
C
1128