Synthesis and in vitro antitumor activity of phenanthrolin-7-one derivatives, analogues of the marine pyridoacridine alkaloids ascididemin and meridine: Structure-activity relationship

Article abstract of DOI:10.1021/jm0308702

A series of substituted pyrido[4,3,2-de][1,7] or [1,10]-phenanthrolin-7-ones, analogues of the marine pyridoacridines meridine and ascididemin, have been synthesized on the basis of Diels-Alder reactions involving different quinoline-5,8-diones and N,N-aldehyde-dimethylhydrazones. All the compounds were evaluated for in vitro cytotoxic activity against 12 distinct human cancer cell lines. They all exhibit cytotoxic activity with IC₅₀ values at least of micromolar order.

Full text of DOI:10.1021/jm0308702

3536
J . Med. Chem. 2003, 46, 3536-3545
Syn th esis a n d in Vitr o An titu m or Activity of P h en a n th r olin -7-on e Der iva tives,
An a logu es of th e Ma r in e P yr id oa cr id in e Alk a loid s Ascid id em in a n d Mer id in e:
Str u ctu r e-Activity Rela tion sh ip
Evelyne Delfourne,*,† Robert Kiss,‡ Laurent Le Corre,† Frederic Dujols,† J ean Bastide,† Franc¸oise Collignon,§
Brigitte Lesur,§ Armand Frydman,§ and Francis Darro§
Centre de Phytopharmacie, UMR-CNRS 5054, Universite´ de Perpignan, 52 Avenue de Villeneuve,
66860 Perpignan Cedex, France, Laboratoire d’Histopathologie, Faculte´ de Me´decine, Universite´ Libre de Bruxelles,
808 Route de Lennik, 1070 Bruxelles, Belgique, and Laboratoire Louis Lafon, Centre de Recherches,
19 avenue du Pr Cadiot, B.P. 22, 94701 Maisons-Alfort Cedex, France
Received April 11, 2003
A series of substituted pyrido[4,3,2-de][1,7] or [1,10]-phenanthrolin-7-ones, analogues of the
marine pyridoacridines meridine and ascididemin, have been synthesized on the basis of Diels-
Alder reactions involving different quinoline-5,8-diones and N,N-aldehyde-dimethylhydrazones.
All the compounds were evaluated for in vitro cytotoxic activity against 12 distinct human
cancer cell lines. They all exhibit cytotoxic activity with IC50 values at least of micromolar
order.
In tr od u ction
investigated the tetracyclic pyridophenanthrolin-7-one
compounds c and d , of which the sole structures
previously reported were the unsubstituted ones, by
Matsumoto et al.6 These skeletons constitute the com-
mon moiety of the marine pyridoacridine alkaloids 1 and
2.
We describe herein the synthesis of these compounds
and their in vitro antitumor activity and discuss the
influence of the different substituents on this activity.
Since the discovery of amphimedine in 19831 until
recent isolation and characterization of kuanoniamines
E and F in 2002,2 more than 50 pyridoacridine alkaloids
have been isolated from sponges and ascidians. A
considerable amount of attention has been focused on
this class of compounds due to their potentially valuable
biological activity.3
Ascididemin 1 and meridine 2 are two members of
the pyridoacridine family differing by the attachment
of the benzene ring, the position of a nitrogen atom, and
a hydroxy substituent in meridine. In a previous report,4a
we have shown that this substituent was not necessary
for biological activity, both the unsubstituted analogue
of meridine and ascididemin presenting important cyto-
toxicity on different cell lines. So far, despite the results
of structure-activity study reported by Lindsay et al.,5
the minimal structural requirement for biological activ-
ity of these compounds remains unknown.
Ch em istr y
In a general way, most of the different tetracyclic
compounds were prepared on the basis of hetero-Diels-
Alder reactions. Almost all the reactions involved quino-
line-5,8-dione or substituted-quinoline-5,8-diones as
dienophiles and 2-butenal N,N-dimethylhydrazone or
2-methoxy-2-butenal N,N-dimethylhydrazone as dienes.
Generally, these reactions afforded mixtures of the
corresponding diazaanthraquinones a and b, in low to
moderate yields, with the last compound as the majority
regioisomer.
This isomer was the sole compound isolated in four
cases including addition of crotonaldehyde N,N-di-
methylhydrazone to ethoxycarbonyl-3-quinoline-5,8-
dione, to 2-hydroxyquinoline-5,8-dione or to 2-chloro-
quinoline-5,8-dione. The identification of the two regio-
isomers was realized both on the basis of the IR spectra
of the tricyclic compounds a and b (Scheme 1) (structure
a presented a sole carbonyl band at 1683-1702 cm-1
whereas structures b had two bands, the first one
between 1651 and 1679 cm-1 and the second one at
1684-1705 cm-1) and NMR spectra of the tetracyclic
compounds (this last method was only usable for
compounds unsubstituted at R1). We have shown in a
previous work4c a notable difference in the 1H NMR
chemical shift of the proton at position 4 (ring A). This
proton was deshielded 0.4 ppm in structures d relative
to structure c. For structures c, the chemical shift of
this proton was about 8.68-8.80 ppm and 8.91-9.56
ppm in structure d .
As part of our work on natural pyridoacridines as a
source of new and useful anticancer drugs,4 we have
* To whom correspondence should be addressed. Phone: 33 468 66
22 51, Fax: 33 468 66 22 23, e-mail:delfourn@univ-perp.fr.
† Universite´ de Perpignan.
‡ Universite´ Libre de Bruxelles.
§ Laboratoire Louis Lafon.
10.1021/jm0308702 CCC: $25.00 © 2003 American Chemical Society
Published on Web 07/04/2003

Antitumor Phenanthrolin-7-one Derivatives
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16 3537
Sch em e 1a
a
(a) CHCl3 or CH3CN, Ac2O, MnO2; (b) DMFDEA, DMF, NH4Cl, EtOH.
Sch em e 2a
a
(a) CHCl3 or CH3CN, Ac2O; MnO2; (b) TFA.
The first method to achieve the final ring D annel-
ation was based on Bracher’s methodology,7 involving
in a first step addition of dimethylformamide-diethyl-
acetal in DMF under nitrogen and in the second step,
subsequent cyclization of the formed enamine with
ammonium chloride in ethanol. In some cases, these
reaction conditions resulted in the formation of several
secondary products. For example, it has not been
possible to obtain the tetracyclic compounds 4c, 4d , 7c,
and 7d from the corresponding tricyclic compounds, 4a ,
4b, 7a , and 7b, respectively. Moreover, the two isomers
have a high difference in reactivity of their enamine to
cyclize, reactions of isomers b working better than those
of isomers a , which were realized in high diluted
conditions in order to decrease intermolecular reactions.
A second method of formation of ring D was investigated
to obtain the tetracyclic compounds which could not be
synthesized according to the previous one. It was also
based on a Diels-Alder strategy involving N-BOC-5-
amino-2-penten-1-al dimethylhydrazone as the diene,
the final ring D annelation being in that case realized
by acid treatment (Scheme 2).
The different substituents R1, R2, and R3 of ring A
were introduced according to two pathways: synthesis
starting from the corresponding substituted-quinoline-
5,8-diones or modification of existing substituent either

3538 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16
Delfourne et al.
Sch em e 3a
a
(a) CHCl3, MnO2; (b) DMFDEA, DMF, NH4Cl, EtOH.
of the diazaanthraquinone (e.g., conversion of the nitro
group of 7b into a dimethylamino-group to give 8b) or
during the formation of ring D (e.g., compound 6d with
an hydroxyl group was obtained when the chloro-
diazaanthraquinone 4b′ was reacted with TFA). It has
to be noted that it has not been possible starting with
the diazaanthraquinones 4a and 4b , using Bracher’s
methodology, to obtain the corresponding tetracyclic
compounds 4c and 4d , the chloro group being substi-
tuted into a dimethylamino group. Nevertheless, com-
pound 4c was obtained by action of TFA on the
diazaanthraquinone 4a ′. We were also interested in
an attempt to design bifunctional compounds. Com-
pound 14d was thus obtained from the corresponding
dimethoxy-tricyclic compound 14b, derived from reac-
tion of the dichloro derivative 13b with sodium meth-
ylate. Direct formation of the last cycle using Bracher’s
methodology on this last compound gave compound 15d .
The methoxy group at R5 was introduced involving
2-methoxy-2-butenal N,N-dimethylhydrazone as the
diene in the Diels-Alder reaction (Scheme 3). This
Diels-Alder reaction was performed with four different
quinoline-5,8-diones with lower yields than the same
reactions with 2-butenal N,N-dimethylhydrazone.
The regioselectivity was similar with the two dienes,
and the isomers 16a and 19a were not isolated due to
the low yield of the reaction. The tricyclic compounds
9a , 9b, 17a , and 19b were transformed into the corre-
sponding tetracyclic compound using Bracher’s meth-
odology. In these conditions, 16b did not give the
tetracyclic compound. However, 16b was transformed
into the dimethylamino derivative 18b which led to the
tetracyclic compound 18d .
indirectly assesses the effect of potentially anticancer
compounds on overall growth of adherent cell lines.8 The
IC50 values, i.e., the concentration which reduced the
mean growth value of the 12 cell lines by 50%, was
determined for each drug, as compared to the mean
control growth value. Table 1 illustrates the individual
IC50 values of the different compounds obtained for each
of the 12 cell lines under study; the in vivo global toxic
effects as revealed by the maximun tolerated dose
(MTD) index are also reported in the same table.
Discu ssion
The tetracyclic compounds 3c and 3d have been
already described by Matsumoto et al.6 and the cytotoxic
activity of 3d toward the P388 cell line was reported
(IC50 ) 0.5 µM). Most of the synthesized compounds in
this work have IC50 of micromolar order. Five pairs of
regioisomers c and d have been tested; for three of them
3c,d , 5c,d , and 12c,d the cytoxic activity of the two
isomers was similar. For the couple 9c,d , the isomer
9d was approximatively 10 times more active than 9c
whereas for the couple 17c,d , the isomer 17d was
approximatively 100 times more active than 17c.
Among the different substituents, the methoxy group
gave the more active compounds, the better position of
substitution being R5 and after R1 and R3. The introduc-
tion of a methoxy group both at R5 and R1 led to the
most active compound of the series (17d ). The activity
decreased when the second methoxy group was at R3
instead of R1 (19d ).
The effect of substituents on the cyctotoxicity was
already studied on the two related ascididemin4a and
meridine4b series. A difference in selectivity was ob-
served between the compounds of these series and the
tetracyclic compounds considered in this study. Ascidi-
demin and meridine derivatives exhibited a low cyto-
toxic activity against LoVo cell line whereas pyrido-
phenanthrolines have a normal activity. On the op-
posite, pyridophenanthrolines have low activity against
J 82 cell line, when ascididemin and meridine analogues
have good activity. Despite this difference of selectivity,
Matsumoto et al.6 reported the same mechanism of
P h a r m a cology
In Vitr o Deter m in a tion of th e Dr u g-In d u ced
In h ibition of Hu m a n Ca n cer Cell Lin e Gr ow th . For
each of the compounds under study, six concentrations
were tested on 12 distinct human cancer cell lines
including various histopathological types (glioblastomas
and breast, colon, lung, prostate, and bladder cancers).
We made use of the colorimetric MTT assay, which

Antitumor Phenanthrolin-7-one Derivatives
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16 3539
Ta ble 1. Characterization of the in Vitro Cytotoxic-Related Antitumor Effects (IC50 value × 10-6 M) of the Compounds Listed
cell lines (IC50, µMa)
compounds U-87MG U-373MG SW 1088 T24 J 82 HCT-15
LoVo
MCF7 T-47D
A-549
A-427 PC-3 MTD (mg/kg)
3c
3d
4c
5c
5d
6d
8d
9c
0.5
6
0.8
4
0.1
8
2
0.3
0.05
NTc
NT
6
0.8
4
4
0.8
0.1
6
1
0.6
0.07
4
5
4
0.9
2
6
5
0.3
0.08
0.3
0.8
3
0.7
0.3
8
1
0.5
0.06
5
5
4
3
2
6
4
4
0.9
0.6
1
0.8
0.1
6
2
0.7
0.09
2
2
1
0.9
0.3
5
2
5
0.2
0.6
0.6
0.6
0.2
5
0.9
0.4
0.06
0.7
0.8
1
0.4
3
6
4
7
6
0.8
3
0.8
0.8
0.3
6
1
0.5
0.05
7
5
0.9
5
0.6
0.9
10
10
20
10
5
0.7
0.7
0.8
0.07
6
0.9
0.5
0.07
>10
10
10
4
0.5
0.08
>160
>160
NT
NT
>160
40
9d
0.8
0.7
10d
11d
12c
12d
14d
15d
17c
17d
18d
19d
5
6
6
6
5
5
5
5
5
6
6
6
2
5
5
5
5
5
6
6
5
5
3
0.04
3
>10
5
5
5
6
2
6
6
5
4
5
0.06
4
1
9
9
6
6
6
5
6
6
6
6
6
5
6
5
4
5
0.8
40
40
80
20
> 10
>10
0.8
0.008
3
2
3
5
0.8
0.8
0.04
6
0.007
5
0.8
0.008
6
0.5
0.009 0.2
5
0.6
0.008 0.03
3
0.6
0.005 0.006
3
0.8
6
8
4
0.5
3
0.5
>160
>160
0.7
0.6
1
a
The IC50 value constitutes the concentration of the compound which inhibits the growth of the human cancer cells by 50% as compared
to the control value. Six concentrations ranging from 10 µM to 0.1 nM were assayed on 12 different human cancer cell lines for each
compound under study. The drug-induced effects at cell line growth level were determined by means of the MTT colorimteric assay. Data
represent the mean values for three independant assays. The values for standard errors are not reported here (for the sake in clarity of
b
the tables) because they reach less tha 3% of the mean values. MTD was defined following single ip injection to B6D2F1/jico mice. c NT
) not tested.
(6 × 400 mL), and the organic layers were dried over MgSO4.
action for ascididemin and compound 3d , oxidative
After concentration to dryness, the expected quinone was
damage to DNA via a thiol-dependent conversion of
1
obtained as an orange solid (1.6 g, 92%), mp 170 °C. H NMR
oxygen to DNA-cleaving oxygen radical.
The synthesized pyridophenanthrolines have also
(CDCl3) 2.77 (d, 3H, J ) 0.7 Hz); 6.97 (d, 1H, J ) 10.4 Hz) ;
7.07 (d, 1H, J ) 10.4 Hz) ; 7.49 (s, 1H). 13C NMR (CDCl3) 21.89;
different toxicities depending on the substituent. The
compounds sharing a methoxy group at R5 have the
lower toxicity (except 17d ). There was no clear-cut
relationship between cytotoxicity against the different
cell lines and toxicity; for example, 9d has a good
cytotoxicity associated with a MTD > 160 mg/kg whereas
17d , which is the best cytotoxic compound of the series,
has a relatively high toxicity (MTD ) 20 mg/kg).
In conclusion, a good series of pyridophenanthrolines
with high cytotoxic activity and selectivity was obtained.
Experiments are under way to characterize the mech-
anisms of action of these drugs and to discover further
antitumor activity on in vivo models.
126.22 ; 131.37; 136.96; 139.50; 148.46; 153.62; 155.87; 181.91;
185.78. IR (CHCl3) 1669, 1685 cm-1
.
N-BOC-1-a m in o-3-h yd r oxyp r op a n e. To a solution of
3-amino-1-propanol (2 mL, 27 mmol) in a mixture of dioxane
(60 mL), H2O (30 mL), and 1 N NaOH (30 mL) was added at
0 °C di-tert-butyl dicarbonate (4.2 g, 29.7 mmol). The reaction
mixture was stirred at room-temperature overnight and was
acidified to pH 1 with concentrated HCl. The mixture was
extracted with AcOEt (3 × 50 mL), and the organic layers were
dried over MgSO4 and concentrated over vacuum to give the
1
expected product as a yellow oil (4 g, 85%). H NMR (CDCl3)
1.25 (s, 9H); 1.60 (m, 2H); 3.20 (m, 2H); 3.60 (m, 2H); 5.20 (br.
s, 1H). 13C NMR (CDCl3) 156.88; 79.14; 59.08; 36.89; 32.34;
28.15.
N-BOC-3-a m in op r op a n a l. A suspension of N-BOC-1-
amino-2-hydroxypropane (18 g, 103 mmol), tetrabutylammo-
nium chloride (2.88 g, 10.4 mmol), tetramethyl-1-piperidinyl-
oxy (TEMPO, 1.62 g, 10.4 mmol), and N-chlorosuccinimide (21
g, 157.3 mmol) in a mixture 0.5 N NaHCO3/0.05 N K2CO3 (350
mL) and HCCl3 (350 mL) was vigorously stirred at room
temperature for 2 h. The organic layer was recovered, dried
over MgSO4, and concentrated over vacuum to yield quanti-
tatively the expected aldehyde as an orange oil. 1H NMR
(CDCl3) 1.52 (s, 9H); 2.80 (m, 2H); 3.50 (m, 2H); 4.98 (br. s,
1H); 9.90 (s, 1H). 13C NMR (CDCl3) 23.39 (3C); 29.21; 39.69;
74.18; 150.88; 196.91.
Exp er im en ta l Section
Ch em istr y. Ch em ica l Syn th esis. 1H and 13C NMR spectra
were obtained with a J EOL 400 MHz spectrometer with the
chemical shifts of the remaining protons of the deuterated
solvents serving as internal standards. IR spectra were
obtained with a Perkin-Elmer (1600 series FTIR) spectrometer.
Mass spectra (MS) were recorded on an automass Unicam
spectrometer. Reagents were purchased from commercial
sources and used as received. Chromatography was performed
on silica gel (15-40 µm) using the solvent systems indicated
below. The purity of the different ascididemin analogues was
evaluated on two analytical chromatographic systems. System
I consisted of a inertsil ODS-3, 5 µm column (250 mm × 4.6
mm), CH3CN/H2O/TFA (see composition) at 1 mL/min flow
rate, 260 nm, and system II consisted of a Kromasil SI, 5 µm
100 Α column (250 mm × 4.6 mm), isooctane/EtOH (see
composition) at 1 or 2 mL/min flow rate, 250 nm.
N-BOC-5-a m in o-2-p en ten -1-a l. A solution of N-BOC-3-
aminopropanal (11 g, 63.6 mmol) and formylmethylenetri-
phenylphosphorane (24.3 g, 80 mmol) in benzene (350 mL) was
refluxed for 9 h. The solvent was evaporated over vacuum, and
the crude product was first purified by flash chromatography
(HCCl3) to remove triphenylphosphine and then again (AcOEt/
heptane 8:2) to obtain the expected product as a yellow-orange
1
oil (3.88 g, 29%). H NMR (CDCl3) 1.35 (s, 9H); 2.44 (d, 2H, J
) 6.8 Hz); 3.21 (m, 2H); 4.90 (br. s, 1H); 6.04 (dd, 1H, J ) 8
and 15.6 Hz); 6.74 (td, 1H, J ) 6.8 and 15.6 Hz); 9.39 (d, 1H,
J ) 8 Hz).
N-BOC-5-a m in o-2-p en ten -1-a l d im eth ylh yd r a zon e. N-
BOC-5-amino-2-penten-1-al (3.88 g, 19.5 mmol) was added at
0 °C to a solution of dimethylhydrazine (1.47 mL, 19.5 mmol)
2-Ch lor o-4-m et h ylq u in olin e-5,8-d ion e. A solution of
2-chloro-5,8-dimethoxy-4-methylquinoline9 (2 g, 8.41 mmol)
and cerium ammonium nitrate (16 g, 29.18 mmol) in a mixture
CH3CN/H2O (140 mL/60 mL) was stirred at room temperature
for 40 min. H2O (100 mL) and a saturated solution of NaHCO3
(260 mL) were added, the mixture was extracted with CH2Cl2

3540 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16
Delfourne et al.
and acetic acid (0.3 mL) in ether (30 mL). The reaction mixture
was stirred for 10 min, and the organic layer was separated
and washed with 1 N HCl and brine. After being dried over
MgSO4 and concentration over vacuum, the hydrazone was
the mixture of the two isomers and 85% MnO2 (12.3 g, 120.3
mmol) in HCCl3
(140 mL) was refluxed for 3 h. The second
flash chromatography (CH2Cl2/MeOH 98:2) gave the expected
compounds:
1
(4a ) brown solid (200 mg, 8%).1H NMR (CDCl3) 2.90 (s, 3H);
7.54 (d, 1H, J ) 4.8 Hz); 7.74 (d, 1H, J ) 4.8 Hz); 8.92 (d, 1H,
J ) 4.8 Hz); 8.93 (d, 1H, J ) 4.8 Hz). 13C NMR (CDCl3) 22.50;
126.83; 128.12; 130.78; 131.22; 145.78; 150.11; 151.00; 151.79;
obtained as an orange oil (4.4 g, 94%). H NMR (CDCl3) 1.40
(s, 9H); 2.3 (m, 2H); 2.82 (m, 6H); 3.2 (m, 2H); 4.52 (br. s, 1H);
5.70 (td, 1H, J ) 6.8 and 15.6 Hz); 6.22 (ddd, 1H, J ) 0.8, 8.8
and 15.6 Hz); 6.96 (d, 1H, J ) 8.8 Hz). 13C NMR (CDCl3) 28.15;
33.05; 39.58; 42.51; 78.77; 130.84; 130.95; 135.54; 155.68.
F or m a tion of th e Dia za a n th r a qu in on e Com p ou n d s by
Diels-Ald er Rea ction . Gen er a l Meth od A. A mixture of
dienophile, diene, and acetic anhydride in solvent was stirred.
The solvent was evaporated, and the crude product was
purified by flash chromatography to obtain the mixture of the
two isomers. A mixture of these isomers and 85% MnO2 in
solvent was refluxed for 2 h, cooled, and filtered over Celite.
The filtrate was concentrated over vacum and purified by flash
chromatography to give the two expected isomers.
4-Met h ylp yr id o[2,3-g]q u in olin e-5,10-d ion e (3a ) a n d
4-Meth ylp yr id o[3,2-g]qu in olin e-5,10-d ion e (3b). Method
A was used and involved a mixture of quinoline-5,8-dione (0.5
g, 3.14 mmol), butenal N,N-dimethylhydrazone (0.35 g, 3.14
mmol), and acetic anhydride (0.45 mL, 4.76 mmol) in HCCl3
(20 mL) which was sonicated for 1 h. After the first flash
chromatography (HCCl3), the mixture of the two isomers and
85% MnO2 (1.6 g, 15.6 mmol) in HCCl3 (20 mL) was refluxed
for 2 h. The second flash chromatography (CH2Cl2/MeOH 98:
2) gave the expected compounds:
154.04; 154.17; 180.05; 182.20. IR (HCCl3) 1684 cm-1
.
(4b) brown solid (500 mg, 19%), mp 216 °C. 1H NMR (CDCl3)
2.85 (s, 3H); 7.54 (d, 1H, J ) 4.8 Hz); 7.74 (d, 1H, J ) 5.2 Hz);
8.91 (d, 1H, J ) 4.8 Hz); 8.91 (d, 1H, J ) 5.2 Hz). 13C NMR
(CDCl3) 22.67; 128.35; 130.09; 131.41; 131.99; 145.49; 148.84;
150.02; 151.54; 154.10; 154.14; 180.13; 183.09. IR (HCCl3)
1678; 1696 cm-1
.
4-Ch lor o-9-(N-BOC-1-am in oeth an e)-5,10-dih ydr opyr ido-
[2,3-g]qu in olin e-5,10-d ion e (4a ′) a n d 4-Ch lor o-6-(N-BOC-
1-a m in oeth a n e)-5,10-d ih yd r op yr id o[3,2-g]qu in olin e-5,10-
d ion e (4b′). Method A was used and involved a mixture of
4-chloroquinoline-5,8-dione (0.6 g, 3.1 mmol), N-BOC-5-amino-
2-pentenal N,N-dimethylhydrazone (0.75 g, 3.1 mmol), and
acetic anhydride (0.45 mL, 4.76 mmol) in HCCl3 (8.5 mL)
which was sonicated for 30 min. After concentration, the
mixture and 85% MnO2 (2.7 g, 26.4 mmol) in HCCl3 (22 mL)
was refluxed for 2 h. The second flash chromatography
(CH2Cl2/MeOH 99:1) gave the expected compounds:
(4a ′) brown solid (70 mg, 6%), mp > 260 °C. 1H NMR (CDCl3)
1.35 (s, 9H); 3.45-3.52 (m, 4H); 4.86 (br. s, 1H); 7.56 (d, 1H,
J ) 4.0 Hz); 7.74 (d, 1H, J ) 5.2 Hz); 8.90 (d, 1H, J ) 5.2 Hz);
8.94 (d, 1H, J ) 4.0 Hz). 13C NMR (CDCl3) 28.37; 35.32; 40.30;
79.47; 126.84; 128.04; 130.88; 131.17; 145.78; 150.34; 150.98;
152.29; 154.05; 154.36; 155.88; 179.76; 182.32. IR (HCCl3) 1695
(3a ) brown solid (40 mg, 6%), mp 220 °C.1H NMR (CDCl3)
2.91 (s, 3H); 7.54 (d, 1H, J ) 4.8 Hz); 7.75 (dd, 1H, J ) 4 and
7.6 Hz); 8.67 (dd, 1H, J ) 2 and 7.6 Hz); 8.91 (d, 1H, J ) 4.8
Hz); 9.12 (dd, 1H, J ) 2 and 4 Hz). 13C NMR (CDCl3) 22.75;
127.93; 128.04; 129.32; 131.50; 135.50; 148.73; 149.26; 152.11;
cm-1
.
153.68; 155.47; 181.46; 182.87. IR (HCCl3) 1689 cm-1
.
(3b) brown solid (160 mg, 23%), mp 270 °C. 1H NMR (CDCl3)
2.94 (s, 3H); 7.52 (d, 1H, J ) 4.8 Hz); 7.76 (dd, 1H, J ) 4.8
and 8.4 Hz); 8.59 (dd, 1H, J ) 2 and 8.4 Hz); 8.92 (d, 1H, J )
4.8 Hz); 9.11 (dd, 1H, J ) 2 and 4.8 Hz). 13C NMR (CDCl3)
22.81; 128.30; 128.39; 130.84; 131.55; 135.52; 147.90; 149.95;
151.74; 153.94; 155.35; 180.42; 184.02. IR (HCCl3) 1672; 1700
(4b ′) brown solid (200 mg, 17%), mp > 260 °C. 1H NMR
(CDCl3) 1.35 (s, 9H); 3.4 (m, 2H); 3.51 (m, 2H); 4.86 (br. s, 1H);
7.57 (d, 1H, J ) 4.8 Hz); 7.75 (d, 1H, J ) 5.2 Hz); 8.91 (d, 1H,
J ) 4.8 Hz); 8.95 (d, 1H, J ) 5.2 Hz). 13
C NMR (CDCl3) 28.24;
34.96; 40.33; 79.47; 128.46; 130.15; 131.06; 131.59; 145.20;
148.76; 149.71; 151.74; 153.88; 153.92; 155.84; 179.76; 183.20.
cm-1
.
IR (HCCl3) 1705 cm-1
.
4-(N-BOC-1-a m in oeth a n e)-p yr id o[2,3-g]qu in olin e-5,10-
d ion e (3a ′) a n d 4-(N-BOC-1-a m in oeth a n e)-p yr id o[3,2-g]-
qu in olin e-5,10-d ion e (3b′). Method A was used and involved
a mixture of quinoline-5,8-dione (0.5 g, 3.14 mmol), N-BOC-
5-amino-2-pentenal N,N-dimethylhydrazone (0.76 g, 3.14 mmol),
and acetic anhydride (0.45 mL, 4.76 mmol) in HCCl3 (20 mL)
which was sonicated for 20 min. After the first flash chroma-
tography (HCCl3), the mixture of the two isomers and 85%
MnO2 (1.7 g, 16.6 mmol) in HCCl3 (22 mL) was refluxed for 2
h. The second flash chromatography (CHCl3) gave the expected
compounds:
4-Me t h oxy-9-m e t h ylp yr id o[2,3-g]q u in olin e -5,10-d i-
on e (5a ) a n d 4-Meth oxy-6-m eth ylp yr id o[3,2-g]qu in olin e-
5,10-d ion e (5b). Method A was used and involved a mixture
of 4-methoxyquinoline-5,8-dione (0.5 g, 2.65 mmol), butenal
N,N-dimethylhydrazone (0.32 g, 2.86 mmol), and acetic anhy-
dride (0.4 mL, 4.23 mmol) in HCCl3 (8 mL) which was refluxed
for 1 h. After the first flash chromatography (CH2Cl2/MeOH
98:2), the mixture of the two isomers and 85% MnO2 (2.3 g,
22.48 mmol) in HCCl3 (26 mL) was refluxed for 2 h. The second
flash chromatography (CH2Cl2/MeOH 98:2) gave the expected
compounds:
(3a ′) brown solid (100 mg, 9%).1H NMR (CDCl3) 1.38 (s, 9H);
3.5 (m, 4H); 4.80 (br. s, 1H); 7.58 (d, 1H, J ) 4.8 Hz); 7.76 (dd,
1H, J ) 4.8 and 8.0 Hz); 8.69 (dd, 1H, J ) 2.0 and 8.0 Hz);
(5a ) red solid (57 mg 9%).1H NMR (CDCl3) 2.84 (s, 3H); 4.06
(s, 3H); 7.18 (d, 1H, J ) 6 Hz); 7.46 (d, 1H, J ) 4.4 Hz); 8.871
(d, 1H, J ) 6 Hz); 8.874 (d, 1H, J ) 4.4 Hz). IR (HCCl3) 1683
8,96 (d, 1H, J ) 4.8 Hz); 9.13 (dd, 1H, J ) 2.0 and 4.8 Hz). 13
C
cm-1
.
NMR (CDCl3) 28.43; 35.85; 40.63; 79.67; 128.46; 129.51;
129.71; 131.88; 135.91; 149.04; 149.90; 153.04; 154.25; 155.84;
1
(5b) orange solid (293 mg, 44%). H NMR (CDCl3) 2.80 (s,
3H); 4.05 (s, 3H); 7.2 (d, 1H, J ) 6.0 Hz); 7.48 (d, 1H, J ) 4.8
Hz); 8.85 (d, 1H, J ) 6.0 Hz); 8.88 (d, 1H, J ) 4.8 Hz). 13C
NMR (CDCl3) 21.75; 43.41; 112.74; 119.72; 130.93; 131.04;
148.32; 149.22; 150.26; 151.60; 152.80; 155.11; 181.44; 184.53.
156.21; 181.57; 183.4. IR (HCCl3) 1690 cm-1
.
(3b′) brown solid (100 mg, 9%). 1H NMR (CDCl3) 1.35 (s,
9H); 3.46 (m, 4H); 4.74 (br. s 1H); 7.54 (d, 1H, J ) 4.8 Hz);
7.77 (dd, 1H, J ) 4.8 and 8.0 Hz); 8.60 (dd, 1H, J ) 1.2 and
8.0 Hz); 8.97 (d, 1H, J ) 4.8 Hz); 9.14 (dd, 1H, J ) 1.2 and 4.8
Hz). 13C NMR (CDCl3) 28.30; 35.52; 40.21; 79.51; 128.33;
128.43; 130.90; 131.48; 135.65; 147.83; 150.19; 152.31; 153.97;
155.42; 155.84; 180.20; 184.10. IR (HCCl3) 1672; 1676; 1702
IR (HCCl3) 1675; 1700 cm-1
.
4-Nitr o-9-m eth ylp yr id o[2,3-g]qu in olin e-5,10-d ion e (7a )
a n d 4-Nit r o-6-m et h ylp yr id o[3,2-g]q u in olin e-5,10-d ion e
(7b). Method A was used and involved a mixture of 4-nitro-
quinoline-5,8-dione (0.8 g, 3.92 mmol), butenal N,N-dimethyl-
hydrazone (0.65 g, 5.8 mmol), and acetic anhydride (0.55 mL,
5.8 mmol) in HCCl3 (8 mL) which was sonicated for 30 min.
After the first flash chromatography (CH2Cl2/MeOH 98:2), the
mixture of the two isomers and MnO2 (2.9 g, 28.3 mmol) in
HCCl3 (29 mL) was refluxed for 2 h. The second flash
chromatography (CH2Cl2/MeOH 98:2) gave the expected com-
pounds:
cm-1
.
4-Ch lor o-9-m eth ylpyr ido[2,3-g]qu in olin e-5,10-dion e (4a)
a n d 4-Ch lor o-6-m eth ylp yr id o[3,2-g]qu in olin e-5,10-d ion e
(4b). Method A was used and involved a mixture of 4-chloro-
quinoline-5,8-dione (2 g, 10.32 mmol), butenal N,N-dimethyl-
hydrazone (1.16 g, 10.32 mmol), and acetic anhydride (1.46
mL, 15.48 mmol) in HCCl3 (28 mL) which was sonicated for 1
h. After the first flash chromatography (CH2Cl2/MeOH 98:2)

Antitumor Phenanthrolin-7-one Derivatives
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16 3541
(7a ) yellow solid (110 mg, 11%).1H NMR (CDCl3) 2.98 (s,
3H); 7.19 (d, 1H, J ) 5.6 Hz); 7.54 (d, 1H, J ) 4.8 Hz); 8.79 (d,
1H, J ) 5.6 Hz); 8.94 (d, 1H, J ) 4.8 Hz). IR (HCCl3) 1703
mixture of 5,8-dioxocarbostyril (0.98 g, 5.59 mmol), N-BOC-
5-amino-2-penten-1-al N,N-dimethylhydrazone (1.49 g, 6.15
mmol), and acetic anhydride (5.8 mL, 61.5 mmol) in aceto-
nitrile (30 mL) which was stirred at room temperature for 16
h. After concentration, the mixture and 85% MnO2 (7 g, 68.4
mmol) in HCCl3 (180 mL) was refluxed for 1.5 h. Purification
on flash chromatography (CH2Cl2/MeOH 98:2) gave the ex-
pected compound as a brown solid (230 mg, 12%), mp 252 °C.
1H NMR (CDCl3) 1.36 (s, 9H); 3.49 (m, 4H); 4.73 (br. s, 1H);
6.94 (d, 1H, J ) 9.6 Hz); 7.54 (d, 1H, J ) 4.8 Hz); 8.10 (d, 1H,
J ) 9.6 Hz); 8.89 (d, 1H, J ) 4.8 Hz); 9.66 (br. s, 1H). 13C NMR
(CDCl3) 28.29 (3C); 35.53; 40.24; 77.8; 117.01; 127.87; 128.62;
132.29; 136.18; 138.04; 148.25; 152.26; 153.33; 155.86; 176.36;
cm-1
.
(7b) yellow solid (165 mg, 16%). 1H NMR (CDCl3) 2.85 (s,
3H); 7.6 (d, 1H, J ) 4.8 Hz); 7.74 (d, 1H, J ) 4.8 Hz); 8.99 (d,
1H, J ) 4.8 Hz); 9.33 (d, 1H, J ) 4.8 Hz).
4-(Dim et h yla m in o)-6-m et h ylp yr id o[3,2-g]q u in olin e-
5,10-d ion e (8b). A solution of compound 7b (150 mg, 0.558
mmol) and N,N-dimethylformamide diethyl acetal (DMF-DEA,
0.4 mL, 1.95 mmol) in (2.1 mL) was warmed at 130 °C for 1 h.
After concentration of the solvent over vacuum, the expected
dimethylamino derivative was obtained and used without
181.35. IR (CHCl3) 3457; 3340; 1693; 1663 cm-1
.
1
further purification in the next step (140 mg, 94%). H NMR
2-Me t h oxy-6-m e t h ylp yr id o[2,3-g]q u in olin e -5,10-d i-
on e (12a ) a n d 2-Meth oxy-6-m eth ylp yr id o[3,2-g]qu in o-
lin e-5,10-d ion e (12b ). Method A was used and involved a
mixture of 2-methoxyquinoline-5,8-dione (1.3 g, 6.88 mmol),
2-butenal N,N-dimethylhydrazone (0.81 g, 7.22 mmol), and
acetic anhydride (7.5 mL, 79.5 mmol) in acetonitrile (150 mL)
which was stirred at room temperature for 68 h. MnO2 (85%)
(7 g, 68.4 mmol) was added, and the mixture was stirred at
room temperature for 6 h. Purification on flash chromatogra-
phy (CH2Cl2/MeOH 99:1) gave the expected compounds:
(CDCl3) 2.77 (s, 3H); 3.05 (s, 6H); 6.89 (d, 1H, 6.0 Hz); 7.39 (d,
1H, 4.8 Hz); 8.42 (d, 1H, 6.0 Hz); 8.74 (d, 1H, J ) 4.8 Hz).
3-Me t h oxy-4-m e t h ylp yr id o[2,3-g]q u in olin e -5,10-d i-
on e (9a ) a n d 3-Meth oxy-4-m eth ylp yr id o[3,2-g]qu in olin e-
5,10-d ion e (9b). Method A was used and involved a mixture
of quinoline-5,8-dione (1 g, 6.29 mmol) and 2-methoxy-2-
butenal N,N-dimethylhydrazone10 (1.78 g, 12.57 mmol) in
HCCl3 (25 mL) which was stirred at room temperature for 5
h. After the first flash chromatography (CH2Cl2/MeOH 95:5),
the mixture of the two isomers and MnO2 (1 g, 9.8 mmol) in
HCCl3 (30 mL) was stirred at room temperature for 1 h. The
second flash chromatography (CH2Cl2/MeOH 99:1) gave the
expected compounds:
(12a ) brown solid (100 mg, 6%), mp > 260 °C. 1H NMR
(CDCl3) 2.92 (s, 3H); 4.20 (s, 3H); 7.13 (d, 1H, J ) 8.8 Hz);
7.50 (d, 1H, J ) 5.0 Hz); 8.53 (d, 1H, J ) 8.8 Hz); 8.90 (d, 1H,
J ) 5.0 Hz). 13C NMR (CDCl3) 22.80; 54.72; 117.30; 124.89;
128.96; 131.22; 137.91; 148.23; 149.40; 151.76; 153.55; 167.66;
(9a ) brown solid (110 mg, 7%), mp > 260 °C. 1H NMR
(CDCl3) 2.79 (s, 3H); 4.11 (s, 3H); 7.72 (dd, 1H, J ) 4.8 and
8.1 Hz); 8.66 (s, 1H); 8.67 (dd, 1H, J ) 8.1 and 1.9 Hz); 9.10
(dd, 1H, J ) 4.8 and 1.9 Hz). 13C NMR (CDCl3) 13.03; 56.87;
127.88; 129.50; 129.95; 135.50; 136.64; 139.26; 142.56; 149.33;
180.92; 183.24. IR (CHCl3) 1685, 1603 cm-1
.
(12b) brown solid (550 mg, 32%), mp 128 °C. 1H NMR
(CDCl3) 2.89 (s, 3H); 4.14 (s, 3H); 7.07 (d, 1H, J ) 8.8 Hz);
7.44 (d, 1H, J ) 4.8 Hz); 8.37 (d, 1H, J ) 8.8 Hz); 8.85 (d, 1H,
J ) 4.8 Hz). 13C NMR (CDCl3) 29.69; 54.92; 117.58; 126.24;
128.09; 131.30; 137.73; 147.31; 150.00; 151.34; 153.38; 167.39;
155.11; 157.24; 180.63; 183.56. IR (HCCl3) 1688 cm-1
.
(9b) brown solid (190 mg, 12%), mp > 260 °C. 1H NMR
(CDCl3) 2.77 (s, 3H); 4.12 (s, 3H); 7.74 (dd, 1H, J ) 4.6 and
8.0 Hz); 8.60 (dd, 1H, J ) 8.0 and 1.6 Hz); 8.68 (s, 1H); 9.12
(dd, 1H, J ) 4.6 and 1.6 Hz). 13C NMR (CDCl3) 12.98; 56.93;
127.99; 129.06; 131.27; 135.53; 136.84; 138.81; 143.27; 148.16;
180.44; 183.70. IR (CHCl3) 1698; 1667; 1603 cm-1
.
2,4-Dich lor o-6-m et h ylp yr id o[3,2-g]q u in olin e-5,10-d i-
on e (13b). Method A was used and involved a mixture of 2,4-
chloroquinoline-5,8-dione (0.6 g, 2.63 mmol), 2-butenal di-
methylhydrazone (0.325 g, 2.89 mmol), and acetic anhydride
(5 mL) in CH3CN (120 mL) which was stirred at room
temperature under nitrogen atmosphere, in the dark for 20
h. After concentration, the crude product and MnO2 (85%) (3.65
g, 35.7 mmol) in CHCl3 (140 mL) was stirred at room
temperature for 56 h. Flash chromatography (CH2Cl2 gave the
155.20; 157.16, 179.69; 184.59. IR (HCCl3) 1670; 1692 cm-1
.
3-Eth oxyca r bon yl-6-(2′-N-BOC-a m in oeth yl)p yr id o[3,2-
g]qu in olin e-5,10-d ion e (10b′). Method A was used and
involved a mixture of 3-ethylquinolinecarboxylate-5,8-dione
(1.05 g, 4.54 mmol), N-BOC-5-amino-2-penten-1-al N,N-di-
methylhydrazone (1.1 g, 4.56 mmol), and acetic anhydride
(0.44 mL, 4.6 mmol) in acetonitrile (15 mL) which was stirred
at room temperature for 24 h. After concentration, the mixture
and MnO2 (5 g, 48.9 mmol) in HCCl3 (150 mL) was refluxed
for 1.5 h. The second flash chromatography (CH2Cl2/MeOH 99:
1) gave the expected compound as a brown solid (60 mg, 3%),
1
product as a brown solid (314 mg, 41%), mp 177 °C. H NMR
(CDCl3) 2.87 (s, 3H); 7.56 (d, 1H, J ) 4.8 Hz); 7.79 (s, 1H);
8.93 (d, 1H, J ) 4.8 Hz). 13C NMR (CDCl3) 22.41; 125.44;
127.84; 131.13; 131.30; 147.44; 149.81; 150.62; 151.90; 154.30;
156.58; 179.12; 180.66. IR (CHCl3) 1706; 1683 cm-1
.
1
mp 170 °C. H NMR (CDCl3) 1.36 (s, 9H); 1.47 (t, 3H, J ) 7.4
Hz); 3,52 (m, 4H); 4.51 (q, 2H, J ) 7.4 Hz); 4.78 (br. s, 1H);
7.57 (d, 1H, J ) 5.2 Hz); 8.99 (d, 1H, J ) 5.2 Hz); 9.17 (d, 1H,
J ) 2.2 Hz); 9.64 (d, 1H, J ) 2.2 Hz). 13C NMR (CDCl3) 14.33;
28.40; 35.74; 40.22; 62.62; 79.63; 128.65; 130.33; 130.49;
131.83; 137.30; 149.60; 150.23; 152.72; 154.23; 155.72; 155.98;
163.52; 179.69; 183.38. IR (CHCl3) 3457; 1726; 1705; 1677
2,4-Dim eth oxy-6-m eth ylp yr id o[3,2-g]qu in olin e-5,10-d i-
on e (14b). A mixture of compound 13b (80 mg, 0.27 mmol)
and sodium methoxyde (300 mg Na/40 mL MeOH; 13.04 mmol)
in MeOH (40 mL) was refluxed for 17 h. After concentration,
H2O (50 mL) was added, and the mixture was neutralized with
25% HCl and extracted with CH2Cl2 (3 × 50 mL). The organic
layers were dried over MgSO4, and the solvent was removed
over vacuum to yield quantitatively the expected compound
as a brown solid, mp 219 °C. 1H NMR (CDCl3) 2.88 (s, 3H);
4.03 (s, 3H); 4.07 (s, 3H); 6.53 (s, 1H), 7.45 (d, 1H, J ) 4.8
Hz); 8.83 (d, 1H, J ) 4.8 Hz). 13C NMR (CDCl3) 22.64; 54.73;
56.80; 97.79; 117.61; 129.55; 131.46; 148.67; 149.41; 150.73;
152.96; 167.95; 168.00; 180.91; 183.41. IR (CHCl3) 1701; 1668
cm-1
.
2-H yd r oxy-6-m e t h ylp yr id o[3,2-g]q u in olin e -5,10-d i-
on e (11b). Method A was used and involved a mixture of 5,8-
dioxocarbostyril (1 g, 5.71 mmol), 2-butenal N,N-dimethyl-
hydrazone (0.703 g, 6.28 mmol), and acetic anhydride (6.2 mL,
65.71 mmol) in acetonitrile (220 mL) which was refluxed for 6
h. After the first flash chromatography (CH2Cl2/MeOH 98:2),
85% MnO2 (3 g, 29.3 mmol) and HCCl3 (75 mL) were added,
and the mixture was stirred overnight at room temperature.
The second flash chromatography (CH2Cl2/MeOH 99:1) gave
the expected compound as a beige solid (160 mg, 12%), mp >
cm-1
.
3-Met h oxy-4-m et h yl-6-ch lor op yr id o[3,2-g]q u in olin e-
5,10-d ion e (16b). Method A was used and involved a mixture
of chloroquinolinedione (1.37 g, 7.1 mmol) and 2-methoxy-2-
butenal dimethylhydrazone (1 g, 7.05 mmol) in CHCl3 (45 mL)
which was stirred at room temperature in the dark for 5.5 h.
After the first flash chromatography, CHCl3/MeOH 98:2), the
major isomer and 85% MnO2 (1 g, 9.78 mmol) in CHCl3 (30
mL) was stirred at room temperature for 1 h. The second flash
chromatography (CHCl3/MeOH 97:3) gave the product as a
yellow solid (100 mg, 5%), mp > 260 °C. 1H NMR (CDCl3) 2.68
1
260 °C. H NMR (DMSO-d6) 2.79 (s, 3H); 6.82 (d, 1H, J ) 9.5
Hz); 7.73 (d, 1H, J ) 5.2 Hz); 8.05 (d, 1H, J ) 9.5 Hz); 8.85 (d,
1H, J ) 5.2 Hz); 12.27 (br. s, 1H). 13C NMR (DMSO-d6) 21.92;
114.30; 122.66; 127.30; 131.52; 135.94; 148.60; 149.80; 152.48
(2C); 176.41; 182.13 (2C). IR (CHCl3) 1684; 1664 cm-1
.
2-Hyd r oxy-6-(2′-N-Boc-a m in oeth yl)p yr id o[3,2-g]qu in o-
lin e-5,10-d ion e(11b′). Method A was used and involved a

3542 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16
Delfourne et al.
(s, 3H); 4.11 (s, 3H); 7.71 (d, 1H, J ) 5.2 Hz); 8.64 (s, 1H);
8.90 (d, 1H, J ) 5.2 Hz). 13C NMR (CDCl3) 12.96; 56.97; 128.92;
130.72; 130.98; 136.95; 138.12; 141.93; 145.06; 150.21; 153.85;
g, 2.70 mmol) and DMF-DEA (1.7 mL, 9.91 mmol) in DMF
(4.5 mL) which was warmed at 120 °C, under nitrogen
atmosphere for 1 h. After concentration, NH4Cl (3.5 g, 65.4
mmol) and ethanol (60 mL) were added, and the mixture was
refluxed for 30 min. After concentration, H2O (50 mL) was
added, and the mixture was extracted with CH2Cl2 (3 × 50
mL). After drying, the organic layers were concentrated to give
the expected tetracyclic compound as a green solid (0.6 g, 95%),
mp 240 °C. 1H NMR (CDCl3) 7.68 (dd, 1H, J ) 4.4 and 8.0
Hz); 7.87 (d, 1H, J ) 5.6 Hz); 8.02 (d, 1H, J ) 5.2 Hz); 8.77
(dd, 1H, J ) 1.6 and 8.0 Hz); 9.11 (d, 1H, J ) 5.2 Hz); 9.16
(dd, 1H, J ) 1.6 and 4.4 Hz); 9.19 (d, 1H, J ) 5.6 Hz). 13C
NMR (CDCl3) 120.95; 124.40; 126.14; 129.32; 136.78; 139.09;
147.45; 148.58; 148.82; 148.96; 150.66; 152.00; 155.73; 181.96.
IR (CHCl3) 1681 cm-1. MS m/z 233 (96); 205 (100); 178 (29). tR
is 5.41 min (98.7% purity), using system I (CH3CN/H2O/TFA
20:80:0.1), and tR is 7.85 min (97.3% purity), using system II
(isooctane/EtOH 70:30), flow rate 2 mL/min.
157.55; 179.31; 183.67. IR (CHCl3) 1696; 1684 cm-1
.
3,9-Dim eth oxy-4-m eth ylp yr id o[2,3-g]qu in olin e-5,10-d i-
on e (17a , tr icycle73) a n d 3,6-Dim eth oxy-4-m eth ylp yr id o-
[3,2-g]qu in olin e-5,10-d ion e (17b). Method A was used and
involved a mixture of 4-methoxyquinoline-5,8-dione (6.0 g,
31.75 mmol) and 2-methoxy-2-butenal dimethylhydrazone
(6.75 g, 47.53 mmol) in CHCl3 (210 mL) which was stirred at
room temperature under nitrogen atmosphere, in the dark,
for 16 h. After the first flash chromatography CHCl3/MeOH
95:5), the mixture of the two isomers and 85% MnO2 (29 g,
283.5 mmol) in CHCl3 (30 mL) was stirred at room tempera-
ture for 1.5 h. The second flash chromatography (CHCl3/MeOH
97:3) gave the expected products:
(17a ) yellow solid (245 mg, 3%), mp> 260 °C. 1H NMR
(CDCl3) 2.73 (s, 3H); 4.08 (s, 3H); 4.13 (s, 3H); 7.16 (d, 1H, J
) 5.9 Hz); 8.62 (s, 1H); 8.86 (d, 1H, J ) 5.9 Hz). 13C NMR
(CDCl3) 12.99; 56.89; 56.99; 111.07; 119.54; 128.56; 136.90;
138.40; 143.56; 152.0; 155.52; 156.80; 166.53; 180.24; 184.22.
7H-P yr ido[4,3,2-de][1,7]ph en an th r olin -7-on e (3d). Meth-
od B was used and involved a mixture of compound 3b (0.87
g, 3.88 mmol), DMF-DEA (2.5 mL, 14.6 mmol) in DMF (6.1
mL) which was warmed at 120 °C, under nitrogen atmosphere
for 1 h. After concentration, NH4Cl (4.9 g, 91.6 mmol) and
ethanol (780 mL) were added and the mixture was refluxed
for 30 min. After concentration H2O (50 mL) was added and
the mixture was extracted with CH2Cl2 (3 × 50 mL). After
drying, the organic layers were concentrated to give the
expected tetracyclic compound as a yellow solid (0.72 g, 80%),
IR (CHCl3) 1687 cm-1
.
(17b) brown solid (992 mg, 11%), mp > 260 °C. 1H NMR
(CDCl3) 2.68 (s, 3H); 4.09 (s, 3H); 4.10 (s, 3H); 7.18 (d, 1H, J
) 5.5 Hz); 8.60 (s, 1H); 8.88 (d, 1H, J ) 5.5 Hz). 13C NMR
(CDCl3) 12.85; 56.81; 56.84; 111.14; 121.32; 130.95; 136.43;
137.79; 141.95; 150.31; 155.44; 157.33; 165.97; 180.13; 184.24.
IR (CHCl3) 1678, 1692 cm-1
.
1
mp > 260 °C. H NMR (CDCl3) 7.76 (dd, 1H, J ) 4.4 and 8.0
3-Methoxy-4-methyl-6-dimethylaminopyrido[3,2-g]quino-
lin e-5,10-d ion e (18b). A solution of compound 16b (90 mg,
0.31 mmol), dimethylamine hydrochloride (127 mg, 1.56
mmol), and NaOH (63 mg, 1.56 mmol) in THF/H2O (4 mL:2
mL) was refluxed for 1 h. After concentration, a mixture of
CH2Cl2/MeOH 95:5 (50 mL) was added to the crude product.
The organic layer was separated and dried over MgSO4. After
concentration, the crude product was purified by flash chro-
matography (CH2Cl2/MeOH, 95:5) to give the compound as a
yellow solid (80 mg, 87%), mp > 260 °C. 1H NMR (CDCl3) 2.64
(s, 3H); 3.06 (s, 6H); 4.08 (s, 3H); 6.95 (d, 1H, J ) 5.9 Hz);
8.53 (d, 1H, J ) 5.9 Hz); 8.56 (s, 1H). 13C NMR (CDCl3) 12.62;
43.40; 56.80; 112.39; 120.50; 132.23; 135.90; 136.08; 141.86;
150.53; 151.70; 155.04; 157.19; 180.67; 185.45. IR (CHCl3)
Hz); 7.80 (d, 1H, J ) 5.2 Hz); 7.99 (d, 1H, J ) 5.6 Hz); 8.93 (d,
1H, J ) 5.6 Hz); 9.05 (dd, 1H, J ) 1.6 and 4.4 Hz); 9.17 (dd,
1H, J ) 1.6 and 8.0 Hz); 9.19 (d, 1H, J ) 5.2 Hz). 13C NMR
(CDCl3) 119.39; 120.01; 123.85; 128.15; 132.87; 133.80; 138.65;
147.54; 147.74; 148.93; 149.49; 149.99; 152.97; 180.73. IR
(CHCl3) 1693 cm-1. MS m/z 233 (100); 205 (68); 178 (56); 151
(42). tR is 9.11 min (92% purity), using system I (CH3CN/H2O/
TFA 20:80:0.1), and tR is 10.50 min (100% purity), using system
II (isooctane/EtOH 80:20), Flow rate 2 mL/min.
8-Ch lor o-7H -p yr id o[4,3,2-d e][1,10]p h en a n t h r olin -7-
on e (4c). Method C was used and involved a mixture of
compound 4a ′ (260 mg, 0.67 mmol), and TFA (2.6 mL) which
was stirred for 64 h. After evaporation of TFA, CH2Cl2/MeOH
95:5 (200 mL) and Na2CO3 (50 mL) were added. The residue
was washed with ether to yield the tetracyclic compound as a
brown solid (40 mg, 28%), mp > 260 °C. 1H NMR (CDCl3) 7.68
(d, 1H, J ) 5.2 Hz); 7.89 (d, 1H, J ) 5.5 Hz); 8.01 (d, 1H, J )
5.5 Hz); 8.96 (d, 1H, J ) 5.2 Hz); 9.14 (d, 1H, J ) 5.5 Hz);
9.19 (d, 1H, J ) 5.5 Hz). 13C NMR (CDCl3) 119.87; 120.88;
123.61; 126.31; 129.01; 138.56; 146.87; 147.37; 148.46; 148.94;
149.76; 153.85; 153.96; 179.87. MS (m/z) 268 (17); 266 (37);
240 (19); 239 (65); 238 (41); 204 (100). tR is 5.22 min (99.9%
purity), using system I (CH3CN/H2O/TFA 30:70:0.1), and tR is
15.15 min (99.9% purity), using system II (isooctane/EtOH 80:
20), flow rate 2 mL/min.
1693; 1654 cm-1
.
2,7-Dim eth oxy-6-m eth ylp yr id o[3,2-g]qu in olin e-5,10-d i-
on e (19b). Method A was used and involved a mixture of
2-methoxyquinoline-5,8-dione (1.0 g, 5.3 mmol) and 2-methoxy-
2-butenal dimethylhydrazone (0.75 g, 5.3 mmol) in THF (70
mL) which was stirred at room temperature under nitrogen
atmosphere, in the dark for 40 h. After concentration the crude
product and 85% MnO2 (5.4 g, 53 mmol) in CHCl3 (80 mL)
was stirred at room temperature for 2 h. Flash chromatogra-
phy (CHCl3) gave the product as a brown solid (120 mg, 8%),
1
mp > 260 °C. H NMR (CDCl3) 2.74 (s, 3H); 4.09 (s, 3H); 4.20
(s, 3H); 7.09 (d, 1H, J ) 8.4 Hz); 8.41 (d, 1H, J ) 8.4 Hz); 8.63
(s, 1H). 13C NMR (CDCl3) 54.41; 57.43 (2C); 116.44; 125.13;
125.62; 129.64; 137.76; 139.53; 142.19; 148.19; 153.58; 165.72;
8-Meth oxy-7H-p yr id o[4,3,2-d e][1,10]p h en a n th r olin -7-
on e (5c). Method B was used and involved a mixture of
compound 5a (0.74 g, 2.91 mmol) and DMF-DEA (2 mL, 11.7
mmol) in DMF (5.2 mL) which was warmed at 120 °C, under
nitrogen atmosphere for 1 h. After concentration, NH4Cl (4.5
g, 84.1 mmol) and ethanol (67 mL) were added, and the
mixture was refluxed for 30 min. After concentration, H2O (50
mL) was added, and the mixture was extracted with CH2Cl2
(3 × 50 mL). After drying, the organic layers were concen-
trated, and the crude product was purified by flash chroma-
tography (HCCl3/MeOH 98:2) to give the expected tetracyclic
166.67; 177.99; 181.13. IR (CHCl3) 1693; 1667 cm-1
.
F or m a tion of th e Tetr a cyclic Com p ou n d s. Gen er a l
Met h od B. A mixture of diazaantraquinone and dimethyl-
formamide diethylacetal in DMF was warmed at 120 °C under
nitrogen atmosphere for 1 h. After concentration of the solvent,
NH4Cl and solvent were added, and the reaction media was
refluxed. The solvent was removed, H2O was added, and the
mixture was extracted with CH2Cl2. The organic layers were
dried over MgSO4, and the crude product was purified to give
the expected tetracyclic compound. Gen er a l Meth od C. A
mixture of diazaanthraquinone and trifluoroacetic acid was
stirred at room temperature. TFA was removed over vacum,
and NaHCO3 saturated solution and CH2Cl2/MeOH 95:5 were
added. The organic layer was recovered and dried over MgSO4.
The solvent was removed over vacuum to yield the tetracyclic
compound.
1
compound as an orange solid (0.28 g, 37%), mp > 260 °C. H
NMR (CDCl3) 4.20 (s, 3H); 7.13 (d, 1H, J ) 5.6 Hz); 7.82 (d,
1H, J ) 5.2 Hz); 7.94 (d, 1H, J ) 6.0 Hz); 8.92 (d, 1H, J ) 5.6
Hz); 9,07 (d, 1H, J ) 6.0 Hz); 9.13 (d, 1H, J ) 5.2 Hz). 13C
NMR (CDCl3) 56.77; 109.26; 119.08; 119.70; 120.47; 123.09;
138.50; 147.85; 148.25; 148.69; 150.66; 154.08; 155.68; 167.54;
180.40. IR (CHCl3) 1677 cm-1. MS m/z 263 (89); 262 (100); 234
(40); 233 (38); 206 (30); 205 (75). tR is 3.75 min (99.7% purity),
using system I (CH3CN/H2O/TFA 20:80:0.1), and tR is 11.69
7H-P yr ido[4,3,2-de][1,10]ph en an th r olin -7-on e (3c). Meth-
od B was used and involved a mixture of compound 3a (0.63

Antitumor Phenanthrolin-7-one Derivatives
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16 3543
min (97.0%purity), using system II (isooctane/EtOH 60:40),
flow rate 2 mL/min.
and 1.9 Hz); 9.10 (d, 1H, J ) 6.0 Hz); 9.13 (dd, 1H, J ) 1.9
and 4.8 Hz). 13C NMR (CDCl3) 56.97; 115.63; 120.81; 125.52;
129.02; 129.16; 130.22; 136.24; 139.81; 147.37; 149.31; 151.65;
153.07; 154.81; 180.34. IR (HCCl3) 1674 cm-1. tR is 4.57 min
(99.5% purity), using system I (CH3CN/H2O/TFA 30:70:0.1),
and tR is 5.59 min (99.4%purity), using system II (isooctane/
EtOH 70:30), flow rate 2 mL/min.
11-Meth oxy-7H-p yr id o[4,3,2-d e][1,7]p h en a n th r olin -7-
on e (5d ). Method B was used and involved a mixture of
compound 5b (1.14 g, 4.48 mmol) and DMF-DEA (3 mL, 17.5
mmol) in DMF (8 mL) which was warmed at 120 °C, under
nitrogen atmosphere for 1 h. After concentration, NH4Cl (4.5
g, 84.1 mmol) and ethanol (67 mL) were added, and the
mixture was refluxed for 30 min. After concentration, H2O (50
mL) was added, and the mixture was extracted with CH2Cl2
(3 × 50 mL). After drying, the organic layers were concen-
trated, and the crude product was purified by flash chroma-
tography (HCCl3/MeOH 98:2) to give the expected tetracyclic
compound as a yellow solid (0.59 g, 50%), mp > 260 °C. 1H
NMR (CDCl3) 4.15 (s, 3H); 7.26(d, 1H, J ) 6.0 Hz); 7.70 (d,
1H, J ) 6.0 Hz); 7.96 (d, 1H, J ) 5.6 Hz); 8.85 (d, 1H, J ) 6.0
Hz); 8.97 (d, 1H, J ) 6.0 Hz); 9.15 (d, 1H, J ) 5.6 Hz). 13C
NMR (CDCl3) 57.05; 111.33; 118.72; 119.61; 122.12; 124.29;
138.56; 146.71; 147.10; 148.69; 149.81; 150.96; 153.13; 165.83;
180.82. IR (CHCl3) 1691 cm-1. MS m/z 263 (87); 262 (100); 234
(28); 205 (69). tR is 3.76 min (99.1% purity), using system I
(CH3CN/H2O/TFA 20:80:0.1), and tR is 22.66 min (99.1%
purity), 11.69 min using system II (isooctane/EtOH 60:40), flow
rate 2 mL/min.
4-Met h oxy-7H -p yr id o[4,3,2-d e][1,7]p h en a n t h r olin -7-
on e (9d ). Method B was used and involved a mixture of
compound 9b (100 mg, 0.39 mmol), DMF-DEA (0.27 mL, 1.58
mmol) in DMF (0.7 mL) which was warmed at 120 °C, under
nitrogen atmosphere for 1 h. After concentration, NH4Cl (0.6
g, 11.2 mmol) and ethanol (90 mL) were added, and the
mixture was refluxed for 30 min. After concentration, H2O (10
mL) was added, and the mixture was extracted with CH2Cl2
(3 × 10 mL). After drying, the organic layers were concen-
trated, and the crude product was purified by flash chroma-
tography (CH2Cl2/MeOH 98:2) to give the expected tetracyclic
compound as a yellow solid (60 mg, 59%), mp > 260 °C. 1H
NMR (CDCl3) 4.27 (s, 3H); 7.74 (dd, 1H, J ) 4.4 and 8.1 Hz);
8.08 (d, 1H, J ) 5.6 Hz); 8.72 (s, 1H); 8.93 (d, 1H, J ) 5.6 Hz);
9.05 (dd, 1H, J ) 1.9 and 4.4 Hz); 9.19 (dd, 1H, J ) 1.9 and
8.1 Hz). 13C NMR (CDCl3) 57.03; 115.16; 119.70; 127.69;
129.48; 130.15; 132.86; 133.74; 140.82; 146.80; 147.98; 148.63;
152.81; 152.98; 179.84. IR (HCCl3) 1679 cm-1. tR is 13.75 min
(99.5% purity), using system I (CH3CN/H2O/TFA 30:70:0.1),
and tR is 11.45 min (95.3%purity), using system II (isooctane/
EtOH 80:20), flow rate 1 mL/min.
11-Hyd r oxy-7H-p yr id o[4,3,2-d e][1,7]p h en a n th r olin -7-
on e (6d ). Method C was used and involved a mixture of
compound 4b′ (50 mg, 0.129 mmol), and TFA (0.5 mL) which
was stirred for 24 h. After evaporation of TFA, CH2Cl2 (10 mL)
and NaHCO3 (until pH 10) were added. Concentration of the
organic layer gave the expected tetracyclic as a yellow solid
10-E t h oxyca r b on yl-7H -p yr id o[4,3,2-d e][1,7]p h en a n -
th r olin -7-on e (10d ). Method C was used and involved a
mixture of compound 10b′ (30 mg, 0.07 mmol) and TFA (0.27
mL, 3.5 mmol) which was stirred for 64 h. After evaporation
of TFA, CH2Cl2 (15 mL) and NaHCO3 (10 mL) were added.
Concentration of the organic layer and purification of the crude
product by flash chromatography (CH2Cl2) gave the expected
tetracyclic compound as a yellow solid (11.3 mg, 53%), mp 246
1
(20 mg, 63%), mp > 260 °C. H NMR (CDCl3) 7.20 (d, 1H, J )
5.6 Hz); 7.83 (d, 1H, J ) 6.0 Hz); 8.00 (d, 1H, J ) 6.0 Hz);
8.72 (d, 1H, J ) 6.0 Hz); 8.76 (d, 1H, J ) 6.0 Hz); 9.24 (d, 1H,
J ) 5.6 Hz), 14.65 (s, 1H). 13C NMR (DMSO-d6) 116.47; 117.05;
118.90; 119.74; 123.74; 138.58; 143.86; 14.92; 14.73; 15.15;
15.55; 16.78; 180.29. tR is 4.81 min (98.3% purity), using system
I (CH3CN/H2O/TFA 10:90:0.1), and tR is 15.57 min (96.1%
purity), using system II (isooctane/EtOH 80:20), flow rate 2
mL/min.
1
°C. H NMR (CDCl3) 1.49 (t, 3H, J ) 7.3 Hz); 4.53 (q, 2H, J )
7.3 Hz); 7,85 (d, 1H, J ) 5.9 Hz); 8.03 (d, 1H, J ) 5.5 Hz);
8.98 (d, 1H, J ) 5.9 Hz); 9.22 (d, 1H, J ) 5.5 Hz); 9.56 (d, 1H,
J ) 1.9 Hz); 9.73 (d, 1H, J ) 1.9 Hz). 13C NMR (CDCl3) 14.32;
62.29; 119.61; 120.39; 124.04; 129.94; 132.60; 135.46; 138.77;
147.74; 148.78; 149.17; 149.46; 153.23; 164.15; 180.20 (1C not
observed). IR (CHCl3) 1694; 1726 cm-1. MS: m/z 305 (91); 304
(100); 260 (7); 232 (93); 204 (24). tR is 5.16 min (94.5% purity),
using system I (CH3CN/H2O/TFA 50:50:0.1), and tR is 9.13 min
(98.6%purity), using system II (isooctane/EtOH 80:20), flow
rate 2 mL/min.
11-(Dim et h yla m in o)-7H -p yr id o[4,3,2-d e][1,7]p h en a n -
th r olin -7-on e (8d ). Method B was used and involved a
mixture of compound 8b (80 mg, 0.3 mmol), DMF-DEA (0.21
mL, 1.22 mmol) in DMF (1.2 mL) which was warmed at 120
°C, under nitrogen atmosphere for 1 h. After concentration,
NH4Cl (0.5 g, 9.3 mmol) and ethanol (80 mL) were added, and
the mixture was refluxed for 40 min. After concentration H2O
(5 mL) was added, and the mixture was extracted with CH2Cl2
(3 × 5 mL). After drying, the organic layers were concentrated
to give quantitatively the expected tetracyclic compound as a
9-H yd r oxy-7H -p yr id o[4,3,2-d e][1,7]p h en a n t h r olin -7-
on e (11d ). Method C was used and involved a mixture of
compound 11b′ (50 mg, 0.135 mmol) and TFA (0.54 mL, 7
mmol) in CH2Cl2 (30 mL) which was stirred for 48 h. After
evaporation of TFA, a saturated solution of NaHCO3 (13 mL)
was added, and the mixture was extracted with CH2Cl2 (7 ×
30 mL). Concentration of the organic layer and purification of
the crude product by flash chromatography (CH2Cl2/MeOH 97:
2) gave the expected tetracyclic compound as an orange solid
1
red solid, which decomposes before melting. H NMR (CDCl3)
3.00 (s, 6H); 7.09 (d, 1H, J ) 5.2 Hz); 7.57 (d, 1H, J ) 5.6 Hz);
7.90 (d, 1H, J ) 5.2 Hz); 8.54 (d, 1H, J ) 5.2 Hz); 8.89 (d, 1H,
J ) 5.2 Hz); 9.11 (d, 1H, J ) 5.6 Hz). 13C NMR (CDCl3) 44.39
(2C); 114.03; 117.24; 119.27; 119.72; 123.95; 138.71; 146.66;
147.09; 148.74; 150.46; 151.14; 151.75; 156.77; 181.74. IR
(CHCl3) 1689 cm-1. MS m/z 276 (24); 275 (32); 261 (100); 260
(95); 247 (34); 246 (38). tR is 4.08 min (97.3% purity), using
system I (CH3CN/H2O/TFA 10:90:0.1), and tR is 14.34 min
(98.8%purity), using system II (isooctane/EtOH 70:30), flow
rate 2 mL/min.
4-Meth oxy-7H-p yr id o[4,3,2-d e][1,10]p h en a n th r olin -7-
on e (9c). Method B was used and involved a mixture of
compound 9a (100 mg, 0.39 mmol) and DMF-DEA (0.27 mL,
1.58 mmol) in DMF (0.7 mL) which was warmed at 120 °C,
under nitrogen atmosphere for 1 h. After concentration, NH4Cl
(0.6 g, 11.2 mmol) and ethanol (90 mL) were added, and the
mixture was refluxed for 30 min. After concentration H2O (10
mL) was added, and the mixture was extracted with CH2Cl2
(3 × 10 mL). After drying, the organic layers were concen-
trated, and the crude product was purified by flash chroma-
tography (CH2Cl2/MeOH 95:5) to give the expected tetracyclic
compound as a brown solid (85 mg, 83%), mp > 260 °C. 1H
NMR (CDCl3) 4.27 (s, 3H); 7.65 (dd, 1H, J ) 4.8 and 8.0 Hz);
8.15 (d, 1H, J ) 6.0 Hz); 8.70 (s, 1H); 8.78 (dd, 1H, J ) 8.0
1
(16.8 mg, 50%), mp > 260 °C. H NMR (CDCl3) 7.17 (d, 1H, J
) 8.8 Hz); 7.69 (d, 1H, J ) 5.9 Hz); 7.93 (d, 1H, J ) 5.5 Hz);
8.85 (d, 1H, J ) 5.9 Hz); 8.99 (d, 1H, J ) 8.8 Hz); 9.16 (d, 1H,
J ) 5.5 Hz). IR (CHCl3) 1690; 1667; 1602 cm-1. MS: m/z 249
(100); 221 (78); 193 (99). tR is 11.41 min (99.7% purity), using
system I (CH3CN/H2O/TFA 20:80:0.1), and tR is 11.63 min
(97.8% purity), using system II (isooctane/EtOH 80:20), flow
rate 2 mL/min.
9-Meth oxy-7H-p yr id o[4,3,2-d e][1,10]p h en a n th r olin -7-
on e (12c). Method B was used and involved a mixture of
compound 12a (83 mg, 0.33 mmol), DMF-DEA (0.21 mL, 1.23
mmol) in DMF (1 mL) which was warmed at 120 °C, under
nitrogen atmosphere for 1 h. After concentration, NH4Cl (0.48
g, 8.97 mmol) and ethanol (80 mL) were added, and the
mixture was refluxed for 30 min. After concentration, a
saturated solution of NaHCO3 (30 mL) was added, and the
mixture was extracted with CH2Cl2 (3 × 60 mL). After drying,
the organic layers were concentrated, and the crude product

3544 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16
Delfourne et al.
was purified by flash chromatography (CH2Cl2/MeOH 98:2) to
give the tetracyclic compound as yellow solid (55 mg, 64%),
mp > 260 °C. H NMR (CDCl3) 4.30 (s, 3H); 7.05 (d, 1H, J )
mmol) in DMF (3.5 mL) which was warmed at 120 °C for 4 h.
After concentration, NH4Cl (2.0 g, 37.4 mmol) and MeOH (300
mL) were added and the mixture was refluxed for 9 h. After
concentration, H2O (200 mL) was added and the mixture
extracted with CH2Cl2 (4 × 200 mL). flash chromatography
(CH2Cl2/MeOH 97:3) gave the expected compound as a brown
solid (56 mg 17%), mp > 260 °C. 1H NMR (CDCl3) 4.13 (s, 3H);
4.24 (s, 3H); 7.13 (d, 1H, J ) 5.9 Hz); 8.11 (d, 1H, J ) 5.9 Hz);
8.67 (s, 1H); 8.93 (d, 1H, J ) 5.9 Hz); 9.09 (d, 1H, J ) 5.9 Hz).
13C NMR (CDCl3) 56.71; 56.88; 109.08; 115.72; 119,42; 120.02;
129.02; 130.19; 140.83; 147.54; 149.82; 152.48; 154.30; 155.30;
167.62; 179.75. IR (CHCl3) 1670 cm-1. MS: m/z 293 (44); 279
(13); 278 (100). tR is 3.67 min (100% purity), using system I
(CH3CN/H2O/TFA 30:70:0.1), and tR is 12.89 min (99.5%
purity), using system II (isooctane/EtOH 70:30), flow rate 2
mL/min.
1
8.8 Hz); 7.83 (d, 1H, J ) 5.5 Hz); 7.97 (d, 1H, J ) 5.5 Hz);
8.64 (d, 1H, J ) 8.8 Hz); 9.10 (d, 1H, J ) 5.5 Hz); 9.16 (d, 1H,
5.5 Hz). 13C NMR (CDCl3) 54.64; 114.60; 120.50; 120.55;
123.65; 124.45; 138.57; 138.97; 147.38; 148.13; 148.53; 150.67;
151.51; 167.58; 180.88. IR (CHCl3) 1669, 1593 cm-1. MS: m/z
263 (77); 233 (99); 204 (35). tR is 6.78 min (99.7% purity), using
system I (CH3CN/H2O/TFA 30:70:0.1), and tR is 20.43 min
(97.8%purity), using system II (isooctane/EtOH 80:20), flow
rate 1 mL/min.
9-Met h oxy-7H -p yr id o[4,3,2-d e][1,7]p h en a n t h r olin -7-
on e (12d ). Method B was used and involved a mixture of
compound 12b (200 mg, 0.79 mmol) and DMF-DEA (0.47 mL,
2.74 mmol) in DMF (3.2 mL) which was refluxed, under
nitrogen atmosphere for 2 h. After concentration, NH4Cl (1.4
g, 26.2 mmol) and ethanol (200 mL) were added, and the
mixture was refluxed for 30 min. After concentration, H2O (50
mL) was added, and the mixture was extracted with CH2Cl2
(5 × 40 mL). After drying, the organic layers were concen-
trated, and the crude product was purified by flash chroma-
tography (CH2Cl2/MeOH 99:1) to give the tetracyclic compound
as a brown solid (20 mg, 10%), mp > 260 °C. 1H NMR (CDCl3)
4.14 (s, 3H); 7.11 (d, 1H, J ) 8.8 Hz); 7.63 (d, 1H, J ) 5.5 Hz);
7.87 (d, 1H, J ) 5.5 Hz); 8.77 (d, 1H, J ) 5.5 Hz); 8.91 (d, 1H,
J ) 8.8 Hz); 9.09 (d, 1H, J ) 5.5 Hz). 13C NMR (CDCl3) 53.41;
117.66; 118.54; 118.93; 123.70; 127.73; 136.29; 138.52; 145.95;
147.45; 148.03; 148.83; 150.19; 165.86; 180.55. IR (CHCl3) 1686
cm-1. MS: m/z 263 (8); 233 (25); 204 (30). tR is 12.87 min (99.6%
purity), using system I (CH3CN/H2O/TFA 30:70:0.1), and tR is
11.14 min (96.0% purity), using system II (isooctane/EtOH 80:
20), flow rate 1 mL/min.
4,11-Dim eth oxy-7H-pyr ido[4,3,2-de][1,7]ph en an th r olin -
7-on e (17d ). Method B was used and involved a mixture of
compound 17b (100 mg, 0.35 mmol) and DMFDEA (0.24 mL,
1.23 mmol) in DMF (1 mL) which was warmed at 120 °C for
1.5 h. After concentration, NH4Cl (0.6 g, 11.2 mmol) and EtOH
(100 mL) were added, and the mixture was refluxed for 30
min. After concentration, H2O (30 mL) was added and the
mixture extracted with CHCl3 (3 × 75 mL). Flash chromatog-
raphy (CHCl3/MeOH 95:5) gave the expected compound as a
1
yellow solid (27 mg, 26%), mp > 260 °C. H NMR (DMSO-d6)
4.08 (s, 3H); 4.26 (s, 3H); 7.54 (d, 1H, J ) 5.9 Hz); 7,98 (d, 1H,
5,9 Hz); 8,77 (d, 1H, J ) 5.9 Hz); 8.83 (s, 1H); 8.94 (d, 1H, J
) 5.9 Hz). 13C NMR (DMSO-d6) 57.41; 58.07; 112.43; 113.75;
119.84; 122.13; 129.60; 130.54; 140.17; 146.81; 150.17; 150.62;
153.03; 153.35; 166.06; 179.30. IR (CHCl3) 1682; 1608; 1572
cm-1. MS: m/z 293 (34); 292 (42); 220 (19); 192 (30); 165 (22).
tR is 3.71 min (98.0% purity), using system I (CH3CN/H2O/
TFA 30:70:0.1), and tR is 16.60 min (95.3%purity), using system
II (isooctane/EtOH 70:30), flow rate 2 mL/min.
9,11-Dim eth oxy-7H-pyr ido[4,3,2-de][1,7]ph en an th r olin -
7-on e (14d ). Method B was used and involved a mixture of
compound 14b (105 mg, 0.37 mmol) and DMFDEA (0.22 mL,
1.29 mmol) in DMF (1.5 mL) which was warmed at 120 °C for
1.5 h. After concentration, NH4Cl (0.7 g, 13.1 mmol) and EtOH
(95 mL) were added, and the mixture was refluxed for 30 min.
After concentration, H2O (50 mL) was added and the mixture
extracted with CH2Cl2 (5 × 40 mL). Flash chromatography
(CH2Cl2/MeOH 99:1) gave the expected compound as an orange
4-Meth oxy-11-(dim eth ylam in o)-7H-pyr ido[4,3,2-de][1,7]-
p h en a n th r olin -7-on e (18d ). Method B was used and in-
volved a mixture of compound 18b (80 mg, 0.27 mmol) and
DMFDEA (0.18 mL, 1.05 mmol) in DMF (2 mL) which was
warmed at 120 °C for 3 h. After concentration, NH4Cl (0.4 g,
7.48 mmol) and EtOH (90 mL) were added, and the mixture
was refluxed for 30 min. After concentration, H2O (30 mL) was
added and the mixture extracted with CH2Cl2 (3 × 50 mL).
flash chromatography (CH2Cl2/MeOH 95:5) gave the expected
compound as a red solid (33 mg, 40%), which decomposes
before melting. 1H NMR (CDCl3) 3.02 (s, 6H); 4.23 (s, 3H); 7.08
(d, 1H, J ) 5.9 Hz); 7.87 (d, 1H, J ) 5.5 Hz); 8.54 (d, 1H, J )
5.9 Hz); 8.65 (s, 1H); 8.90 (d, 1H, J ) 5.5 Hz). 13C NMR (CDCl3)
44.28; 56.94; 112.14; 113.63; 119.38; 119.73; 129.31; 129.99;
140.20; 145.81; 150.31; 150.63; 151.41; 152.99; 156.77; 180.57.
IR (CHCl3) 1682 cm-1. MS: m/z 306 (52); 305 (32); 291 (100);
290 (66); 276 (24); 248 (9); 220 (13); 193 (21). tR is 3.69 min
(100% purity), using system I (CH3CN/H2O/TFA 30:70:0.1),
and tR is 10.51 min (100%purity), using system II (isooctane/
EtOH 70:30), flow rate 2 mL/min.
4,9-Dim eth oxy-7H-p yr id o[4,3,2-d e][1,7]p h en a n th r olin -
7-on e (19d ). Method B was used and involved a mixture of
compound 19b (100 mg, 0.35 mmol) and DMFDEA (0.24 mL,
1.4 mmol) in DMF (1 mL) which was warmed at 120 °C for 1
h. After concentration, NH4Cl (0.54 g, 10.1 mmol) and EtOH
(100 mL) were added, and the mixture was refluxed for 30
min. After concentration, H2O (20 mL) was added and the
mixture extracted with CHCl3 (3 × 30 mL). Flash chromatog-
raphy (CHCl3) gave the expected compound as a green solid
(37 mg, 36%), mp > 260 °C. 1H NMR (CDCl3) 4.21 (s, 3H);
4.24 (s, 3H); 7.16 (d, 1H, J ) 8.8 Hz); 7.98 (d, 1H, 5.6 Hz);
8.69 (s, 1H); 8.85 (d, 1H, J ) 5.6 Hz); 9.00 (d, 1H, J ) 8.8 Hz).
13C NMR (DMSO-d6) 54.44; 56.92; 114.04; 117.17; 118.86;
127.74; 129.43; 129.99; 136.29; 141.16; 146.36; 146.72; 149.38;
152.94; 165.80; 179.70. IR (CHCl3) 1679 cm-1. MS: m/z 293
(44); 248 (100); 220 (12). tR is 5.82 min (95.1% purity), using
system I (CH3CN/H2O/TFA 30:70:0.1), and tR is 3.31 min
(98.0%purity), using system II (isooctane/EtOH 70:30), flow
rate 2 mL/min.
1
solid (7 mg, 9%), mp > 260 °C. H NMR (CDCl3) 4.12 (s, 3H);
4.18 (s, 3H); 6.65 (s, 1H); 7.64 (d, 1H, J ) 5.5 Hz); 7.92 (d, 1H,
J ) 5.5 Hz); 8.93 (d, 1H, J ) 5.5 Hz); 9.14 (d, 1H, J ) 5.5 Hz).
13C NMR (CDCl3) 54.39; 57.02; 98.26; 117.89; 118.64; 118.86;
124.16; 138.50; 146.93; 147.09; 148.29; 148.62; 151.50; 166.32;
167.73; 180.65. IR (CHCl3) 1688 cm-1. MS: m/z 293 (15); 292
(28); 233 (24); 204 (13); 165 (10). tR is 3.75 min (99.7% purity),
using system I (CH3CN/H2O/TFA 20:80:0.1), and tR is 8.06 min
(99.4%purity), using system II (isooctane/EtOH 70:30), flow
rate 2 mL/min.
9-Ch lor o-11-(d im eth yla m in o)-7H-p yr id o[4,3,2-d e][1,7]-
p h en a n th r olin -7-on e (15d ). Method B was used and in-
volved a mixture of compound 13b (110 mg, 0.387 mmol) and
DMFDEA (0.23 mL, 1.34 mmol) in DMF (1.1 mL) which was
warmed at 120 °C for 1.5 h. After concentration, NH4Cl (0.7
g, 13.1 mmol) and EtOH (95 mL) were added, and the mixture
was refluxed for 30 min. After concentration, H2O (50 mL) was
added and the mixture extracted with CH2Cl2 (5 × 40 mL).
Flash chromatography (CH2Cl2/MeOH 99:1) gave the expected
1
compound as a red-purple solid (3.3 mg, 3%), mp 246 °C. H
NMR (CDCl3) 3.04 (s, 6H); 7.11 (s, 1H); 7.61 (d, 1H, J ) 5.5
Hz); 7.92 (d, 1H, J ) 5.5 Hz); 8.90 (d, 1H, J ) 5.5 Hz); 9.14 (d,
1H, J ) 5.5 Hz). 13C NMR (CDCl3) 44.39; 113.57; 117.60;
119.00; 119.37; 123.99; 138.50; 146.51; 146.77; 148.83; 150.68;
150.89; 153.68; 158.21; 180.05. IR (CHCl3) 1698 cm-1. MS: m/z
311 (19); 309 (11); 296 (89); 294 (100); 269 (4); 267 (1); 204
(66). tR is 5.85 min (99.7% purity), using system I (CH3CN/
H2O/TFA 30:70:0.1), and tR is 10.87 min (99.3% purity), using
system II (isooctane/EtOH 70:30), flow rate 2 mL/min.
4,8-Dim eth oxy-7H-pyr ido[4,3,2-de][1,10]ph en an th r olin -
7-on e (17c). Method B was used and involved a mixture of
compound 17a (330 mg, 1.17 mmol), DMFDEA (0.9 mL, 5.25

Antitumor Phenanthrolin-7-one Derivatives
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 16 3545
P h a r m a cology. In Vitr o Ch a r a cter iza tion of Dr u g-
In d u ced Effects w ith Resp ect to Hu m a n Ca n cer Cell
Lin e Gr ow th . Twelve human tumor cell lines were obtained
from the American Type Culture Collection (ATCC, Manassas,
VA). These included three glioblastomas (A-172, U-373 MG
and U-87 MG), two colon (HCT-15 and LoVo), two non-small-
cell-lung (A549 and A-427), two bladder (J 82 and T24), one
prostate (PC-3), and two breast (T-47D and MCF7) cancer
models. The ATCC numbers of these cell lines are CRL1620
(A-172), HTB 14 (U-87 MG), HTB 17 (U-373 MG), CCL225
(HCT-15), CCL229 (LoVo), CCL 185 (A549), HBT 53 (A-427),
HTB1 (J 82), HTB4 (T24), HTB133 (T-47D), HTB22 (MCF7),
and CRL1435 (PC-3). The cells were cultured at 37 °C in sealed
(airtight) Falcon plastic dishes (Nunc, Gibco, Belgium) con-
taining Eagle’s minimal essential medium (MEM, Gibco)
supplemented with 5% fetal calf serum (FCS). All the media
were supplemented with a mixture of 0.6 mg/mL glutamine
(Gibco), 200 IU/mL penicillin (Gibco), 200 IU/mL streptomycin
(Gibco), and 0.1 mg/mL gentamycin (Gibco). The FCS was
heat-inactivated for 1 h at 56 °C.
fitting of the data by means of the ø2 test of goodness-of-fit.
When these parametric conditions were not satisfied, the
nonparametric Kruskall-Wallis (for more than two groups) or
the Mann-Whitney (for two groups) tests were carried out.
All the statistical analyses were carried out using Statistica
(Statsoft, Tulsa, OK).
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The 12 cell lines were incubated for 24 h in 96-microwell
plates (at a concentration of 40000 cells /mL culture medium)
to ensure adequate plating prior to cell growth determination,
which was carried out by means of the colorimetric MTT assay,
as detailed previously.11,12 This assessment of cell population
growth is based on the capability of living cells to reduce the
yellow product MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-di-
phenyltetrazolium bromide; Sigma, St Louis, MO) to a blue
product, formazan, by a reduction reaction occurring in the
mitochondria. The number of living cells is directly propor-
tional to the intensity of the blue, which is quantitatively
measured by spectrophotometry on a DIAS microplate reader
(Dynatech Laboratories, Guyancourt, France) at a 570 nm
wavelength (with a reference of 630 nm). Each experiment was
carried out in sextuplicate. We validated the MTT-related data
using two alternative techniques, namely direct cell counting
and the genomic incorporation of tritiated thymidine (data not
shown).
Six concentrations ranging from 10-5 to 10-9 M were assayed
for each of the compounds under study (see Table 1).
In Vivo Deter m in a tion of Dr u g-In d u ced Toxicity.
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can be administered acutely (i.e., in one intraperitoneal single
dose) to healthy animals (B6D2F1 mice, Iffa Credo), i.e., not
grafted with tumors. The survival and weight of the animals
are recorded for up to 28 days postinjection. Six different doses
of each drug (5, 10, 20, 40, 80, and 160 mg/kg) are used for
the MTD index determination, with each experimental group
being composed of three mice for this purpose.
Sta tistica l An a lysis. The statistical comparisons of the
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(for two groups) tests after a check of the equality of variance
by means of the Levene test and of the normal distribution
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J M0308702