Synthesis and cytotoxic activity of carboxamide derivatives of benzo[b][1,6]naphthyridin-(5H)ones

Article abstract of DOI:10.1016/j.bmc.2004.11.007

A previous reaction leading to 2-substituted 6-methyl-1-oxo-1,2- dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acids has been extended to encompass a broad range of 2-substituents. Derived carboxamides, particularly 4-N-[2-(dimethylamino)ethyl], were tested for growth inhibitory properties. Potent cytotoxicity against murine P388 leukemia and Lewis lung carcinoma (LLTC) was retained for compounds bearing a remarkably diverse range of 2-substituents with a number having IC₅₀ values <10 nM. Five of the new compounds were tested in vivo against subcutaneous colon 38 tumors in mice; a single dose (1.8 mg/kg) proved curative for the 2-(4-fluorophenyl) derivative, a further increase in potency over the very effective 2-methyl analogue reported previously.

Full text of DOI:10.1016/j.bmc.2004.11.007

Bioorganic & Medicinal Chemistry 13 (2005) 1341–1355
Synthesis and cytotoxic activity of carboxamide derivatives
of benzo[b][1,6]naphthyridin-(5H)ones
Leslie W. Deady,a,* Michael L. Rogers,a Li Zhuang,b Bruce C. Baguleyb
and William A. Dennyb,*
aChemistry Department, La Trobe University, Victoria 3086, Australia
bAuckland Cancer Society Research Centre, Faculty of Medical & Health Sciences, The University of Auckland,
Private bag 92019, Auckland, New Zealand
Received 1 September 2004; revised 4 November 2004; accepted 5 November 2004
Available online 24 November 2004
Abstract—A previous reaction leading to 2-substituted 6-methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acids
has been extended to encompass a broad range of 2-substituents. Derived carboxamides, particularly 4-N-[2-(dimethylamino)ethyl],
were tested for growth inhibitory properties. Potent cytotoxicity against murine P388 leukemia and Lewis lung carcinoma (LLTC)
was retained for compounds bearing a remarkably diverse range of 2-substituents with a number having IC50 values <10nM. Five of
the new compounds were tested in vivo against subcutaneous colon 38 tumors in mice; a single dose (1.8mg/kg) proved curative for
the 2-(4-fluorophenyl) derivative, a further increase in potency over the very effective 2-methyl analogue reported previously.
ꢀ 2004 Elsevier Ltd. All rights reserved.
1.Introduction
properties against tumor cell lines and in vivo activity
of selected examples.
The investigation of topoisomerase poisons as potential
anticancer agents continues to be of interest. Tricyclic
chromophores bearing a flexible cationic side chain
make upone subclass, typified by the acridine-4-carbox-
amides (e.g., DACA, 11,2). With respect to DACA, it
has been found that the peri arrangement between the
amide function and the central ring nitrogen is essential
for anticancer activity.1 We recently reported that car-
boxamide derivatives of the benzo[b][1,6]naphthyridine
system were topoI/II inhibitors and potent cytotoxins,
and initial in vivo testing against subcutaneous colon
38 tumors in mice showed that, for example, a single
dose (3.9mg/kg) of compound 2c was curative.3 This
encouraging result prompted us to further investigate
this series; in particular, the synthesis allows a wide var-
iation in the nature of the 2-substituent. We report here
the preparation of an extended series of such derivatives,
along with some variations in benzo-ring substituents
and carboxamide side chain, their growth inhibitory
O
Me
N
N
N
NMe2
NMe2
Me
Me
CONH
CONH
1
2c
Me
Me
O
B
Me
O
O
N
N
Me
CO2H
5ee
O
CONMe2
CH=CH-NHAr
O
N
N
O
Me
Me
*
Corresponding authors. Tel.: +61 3 94792561; fax: +61 3 94791399
(L.W.D.); fax: +64 3737 502 (W.A.D.); e-mail addresses:
l.deady@latrobe.edu.au; b.denny@auckland.ac.nz
N
OMe
OMe
7
H
9
6
a Ar = Ph; b Ar = C H F-p
6
4
0968-0896/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2004.11.007

1342
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
NMe2
2.Results and discussion
CONH
N
2.1. Chemistry
O
i, ii
iii
N
2n
4n
The general synthetic scheme is that reported previ-
ously.3 The homophthalic acid analogues 3a–d were pre-
pared by adapting a method for the pyridine example.4
Analogue 3e was prepared from 2-aminonicotinalde-
hyde and diethyl 1,3-acetonedicarboxylate by the method
reported for the dimethyl analogue.5 Reaction of 3 with
Vilsmeier reagent gave the key intermediates 4 (Scheme
1).6 In our previous paper,3 compounds 4a and 4b
were reacted with a limited selection of amines under
generally very mild conditions, to give the acids
5a–c,e,o,r,u mostly in good yields. This has now been
extended to the additional 4c–e, and a much wider selec-
tion of amines to introduce considerable variation in the
2-substituent.
N
of Table 1
NMe2
Me
CONH
8b of Table 1
NMe2
iii
CONH
O
N
i, ii
O
2g
4g
of Table 1
N
NMe2
Me
CONH
8a of Table 1
Scheme 2. Reagents and conditions: (i) CDI/dioxan/reflux; (ii) excess
Me2N(CH2)2NH2/CH2Cl2; (iii) 10% NaOH/EtOH/reflux.
Reaction of 4 in dimethylformamide with nucleophilic
alkyl amines was straightforward; an excess of amine
could be used, as previously,3 or with more expensive
amines and those available as hydrochloride salts, a
10% excess in combination with a larger excess of trieth-
ylamine was also satisfactory. The acid products 5 were
generally insoluble and could be filtered directly, though
pound, the excess was kept to 2-fold and the target
was isolated in only 20% yield; in this example, water
was carefully omitted from the workupbecause the
compound was more readily handled at this stage with
the boron in the readily hydrolyzed tetramethyl-1,3,2-
dioxaborolane protected form (5ee). The boronic acid
functionality was liberated at the final amide-forming
stage (2v).
7
minor workupvariations were required in some cases.
The reaction with less nucleophilic arylamines was more
complicated. In the sole example reported previously,3
using 3,4-dimethoxyaniline and triethylamine, the initial
solid was the very insoluble 6 and reaction of this with
more amine in refluxing pyridine gave the target 5u.
However, in the arylamine examples now reported, the
presumed analogues of 6 did not precipitate and the
reaction proceeded to the target 5. But an unwanted side
reaction occurred since the dimethylamine liberated in
the first stepcompeted efficiently with the arylamine in
the second stepto form 7. A 10-fold excess of the aryl-
amine was therefore used in order to minimize this reac-
tion and compounds 5 were able to be readily isolated.
In the case of the expensive boron containing com-
The desired amides were formed by reaction of the
appropriate amine with an intermediate acid chloride
(from reaction with thionyl chloride, and not isolated)
or imidazolide (from reaction with 1,10-carbonyldiimid-
azole (CDI), and not isolated). The desmethyl amide 2dd
was prepared by reacting the acid chloride with chloro-
ethylamine and then displacing the chlorine with
methylamine. When the 7-methoxy acid 5w was reacted
with thionyl chloride, clean chlorination ortho to the
methoxy groupalso occurred so that the amide isolated
was 2x. Two acids with reactive functionality in the
2-substituent caused complications in the CDI reaction;
a reaction of CDI with the terminal OH in 5g and indole
NH in 5n occurred so that the amides isolated also
contained carbamate (8a) and urea (8b) groups, respec-
tively (Scheme 2). Careful alkaline hydrolysis removed
each of these while leaving the 4-carboxamide intact
(2g and 2n).
O
4
1
6
CO2R
CO2Et
i
O
Z
Z
N
O
N
6
8
CHNMe2
3
4
a Z = H; b Z = 8-Me; c Z = 7-MeO
d Z = 4-aza; e Z = 8-aza
ii
ii
2p
R = H except e (R = Et)
i
5ff Z = Ac
5q Z = Me
O
O1
of Table 1
OZ
Y
iii, iv
Compounds 2
of Table 1
N
N
Z
iii
N
ii
N
2q
6
Me
CO H
2
CO H
2
of Table 1
5
5p Z = H
Scheme 1. Reagents and conditions: (i) POCl3/DMF/0ꢁC; (ii) excess
YNH2/DMF/20ꢁC OR 1.1molequiv YNH2/excess NEt3/DMF/20ꢁC
OR (for Y = Ar) 10molequiv YNH2/excess NEt3/DMF/20ꢁC; (iii)
SOCl2/reflux OR CDI/dioxan/reflux; (iv) RNH2/CH2Cl2.
Scheme 3. Reagents and conditions: (i) Ac2O/AcOH/60ꢁC/2h; (ii)
SOCl2/reflux 15min then evap. and add excess Me2N(CH2)2NH2/
CH2Cl2/20ꢁC/16h; (iii) 1.1molequiv NaOEt/EtOH and evaporate,
then excess MeI/DMF/110ꢁC/1h.

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1343
The potentially complicating 2-OH group in acid 5p was
2.2. Structure–activity relationships
acetylated prior to amide formation, and deacetylation
readily occurred during this latter reaction of excess
N,N-dimethylethylenediamine with the intermediate
acid chloride to give 2p (Scheme 3). Also from 5p, the
hydroxy groupwas successfully methylated with methyl
iodide and the product, 5q, was converted to the 2-meth-
oxy amide 2q (Scheme 3).
The compounds were evaluated for growth inhibitory
properties, measured as IC50 values, against murine
P388 leukemia cells and Lewis lung carcinoma cells
(LLTC). These lines are commonly used for cytotoxicity
evaluations and the results, along with those of reference
compounds, are summarized in Table 1. The overriding
Table 1. Growth inhibitory activity of 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxamides and reference compounds
O
O
O
9
Me
R
Me
8
N
N
N
R
N
N
N
7
6
Me
R
Me
NMe2
NMe2
O
B
N
O
N
O
N
H
H
H
A
C
a
IC50 (nM)
No
Fm
R
P388b
100
LLTCc
189
DACAd
DACA, 5-Med
Doxorubicin
Etoposide
H
6.4
5.6
31
147
11
22
160
10
2be
2ce
2d
2ee
2f
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B
Me
Et
2.1
3.7
14
61
4.8
1.7
7.3
15
(CH2)3Me
CH2CF3
(CH2)2OH
CH2CO2Et
(CH2)3CO2Et
7
3.4
2g
2h
2i
24
11
16
26
36
2j
CH2(3,4-diOMePh)
(CH2)2(3,4-diOMePh)
CH2(2-pyridyl)
160
810
13
2k
2l
250
20
2m
2n
2oe
2p
2q
2re
2s
(CH2)3(N-pyrrolid-2-one)
(CH2)2(3-indolyl)
(CH2)2NMe2
OH
10
210
26
220
6.8
110
5.6
3.7
105
5
OMe
CH(S-Me)Ph
Ph
4-FPh
590
12
161
2.6
22
4.4
3.4
24
2t
10
12
2ue
2v
3,4-diOMePh
4-B(OH)2Ph
(CH2)2OCO(CH2)2NMe2
(CH2)2Zf
7.1
8a
8b
2aa
2bb
2cc
2dd
2a
2w
2x
2y
2z
30
140
110
20,000
27
CH(S-Me)CONMe2
CH(S-Me)CH2NMe2
CH(R-Me)CH2NMe2
CH2CH2NHMe
H
17,600
13
B
B
7.4
3.1
14e
11
B
3.5
C
C
C
C
C
24
23
7-OMe
36
60
6-Cl, 7-OMe
6-Aza
10-Aza
25
38
19
3600
870
a Concentration of drug to reduce cell number to 50% of control cultures (see text).
b Murine P388 leukemia.
c Murine Lewis lung carcinoma.
d Data from Ref. 10.
e Data from Ref. 3.
f Z =
N
NMe2
CONH

1344
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
Table 2. In vivo activity of 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyri-
dine-4-carboxamides and reference compounds against subcutaneous
colon 38 tumors in mice
feature is that high cytotoxicity is retained over a wide
range of 2-substituent types, but some general trends
are evident. Within alkyl groups, there is a tendency
for activity to diminish with an increase in length of
the carbon chain (Me 2c to Bu 2e) and the introduction
of a polar terminal group has, surprisingly, little effect
(e.g., pairs 2d/2g and 2e/2i). We noted previously3 that
branching at the a-carbon (2r), was not tolerated and
so in the present set all alkyl groups have an a-CH2
group. The various terminal groups in 2f–o, 8a, 8b con-
vey no particular advantage over the original methyl in
2c.
Drug
Dosea Sched.b Growth delay daysc Curesd
2ce
8.9
5.9
3.9
2.6
8.9
5.9
8.9
13.3
8.9
5.9
3.9
2.6
5.9
3.9
2.6
5.9
3.9
2.6
1.8
2.6
45
sd
sd
>20
>20
>20
3/5
10/10
4/4
0/5
3/5
1/5
0/5
2/3
0/4
0/4
4/5
0/5
0/5
1/5
0/5
4/4
5/5
5/5
4/5
0/5
0/5
0/5
sd
sd
6.0
2d
sd
sd
>20
15
2i
2l
sd
sd
2.5
4.5
6.0
5.0
sd
sd
It was noted previously that the only 2-aryl substituent
included in the original set (2u) was highly active.
Now, when successive methylene groups are introduced
between ring N and the same aryl group( 2j and 2k),
activity rapidly drops away.
2ue
2s
sd
sd
>20
16
>20
7
sd
sd
sd
sd
4.5
2t
>20
>20
>20
>20
8
sd
sd
It was of considerable interest that direct attachment of
a benzene ring, in 2u, produced activity comparable with
the simple alkyl analogues.3 It is now evident that this
was not a specific function of the methoxy substituents,
since the ꢀparentꢁ 2s is equally active and groups as di-
verse as 4-borono (2v) and 4-fluoro (2t) are also toler-
ated. The latter result is of interest as the fluoro
substituent blocks a potentially metabolically reactive
site.8
sd
Doxorubicine
Etoposidee
Irinotecane
q4d · 3
q4d · 3
q4d · 3
1.5
7
65
a mgkgꢀ1 dayꢀ1. Drugs were administered as an intraperitoneal dose in
aqueous solution at a volume of 10lL/g body weight. Doses indi-
cated did not induce deaths from toxicity.
b sd = single dose; q4d · 3 = every 4days · 3.
c Growth delays were calculated from the times of control and drug
treated groups took to reach four times the mean pre-treatment
tumor volume. The pre-treatment tumor volume was typically
14mm3.
Limited variations in the carboxamide function have
been studied. The fundamental importance of the termi-
nal nitrogen function is evident; when this is part of a
nonbasic amide (2aa), cytotoxicity is very low in com-
parison with a basic amine (2bb). There is little difference
in activity between compounds with terminal NHMe
(2dd) and NMe2 (2c) groups. In related benzophenazine
carboxamides, the introduction of an a-methyl group
into the 2-(dimethylamino)ethyl side chain provided an
increase in activity, especially for the (R)-enantiomer.9
There is also a slight preference for the (R)-enantiomer
in the present set (2cc), though activity is not as great
as for the nonbranched chain in 2c.
d Cured mice were defined as having no evidence of a measurable
tumor after 20days. Other experiments with drugs in this series
indicated that when such mice were kept for longer times, tumors did
not reappear.
e Data from Ref. 3.
clinical utility to date.12 A selection of the new com-
pounds was therefore studied under a single-dose sche-
dule and the results, along with those of 2c, 2u, and
reference compounds, are summarized in Table 2. None
of the ꢀalkylꢁ subset, 2d (2-Et), 2i [2-(CH2)3CO2Et], 2l [2-
CH2(2-pyridyl)] improved on the activity produced by
the original 2c. However, within the aryl examples, 2t
(4-FPh) provided a noteworthy result where a single
dose as low as 1.8mg/kg had a curative effect. In con-
trast, multiple dosing of the established compounds
listed in Table 2 gave varying growth delays but no
cures.
In this series, we have concentrated on compounds with
the 6-methyl groupsince results with DACA analogues
established that small 5-substituents gave greater cyto-
toxicity,10 and 2a was less active than 2c. Nonetheless,
a few other variations in benzo and center ring substitu-
ents have been included (2w–z), but none is as good as
the 6-methyl and the additional ring nitrogen in 2z has
a profound deleterious effect.
2.3. In vivo studies
3.Conclusions
The curative in vivo activity against subcutaneously im-
planted colon 38 tumors in mice previously found with
2u [2-(3,4-diOMePh)] and especially 2c (2-Me),3
prompted further in vivo work with both 2-alkyl and
2-aryl substituted compounds. This advanced colon 38
tumor model was chosen since it is fairly refractory to
standard clinical topo II agents, as well as to antimeta-
bolites and alkylating agents.11 In vivo colon 38 tumor
models have been shown to be the best predictors for
The 4-N-[2-(dimethylamino)ethyl]-2-substituted-6-meth-
yl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbo-
xamides are confirmed as a class of potent antitumor
agents, with some showing curative in vivo activity in
the sc colon 38 model in a single dosing protocol. In par-
ticular, the 2-(4-fluorophenyl) and 2-methyl derivatives
provide promising candidates to further investigate effi-
cacy and mechanism of action.

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1345
4.Experimental
CO2CH2CH3), 4.49 (s, 2H, CH2CO2Et), 7.52 (dd,
J = 8.0, 4.2Hz, 1H, H-6), 8.27 (d, J = 7.9Hz, 1H, H-
5), 8.84 (s, 1H, H-4), 9.15 (d, J = 2.4Hz, 1H, H-7).
NMR spectra were recorded on a Bruker Avance 300
spectrometer, operating at 300.13MHz (1H) and
75.47MHz (13C), and a Bruker DRX-400 spectrometer
operating at 400.13MHz (1H) and 100.62MHz (13C).
Chemical shifts are reported as d values (ppm) relative
to Me4Si. Standard PENDANT, HSQC, and HMBC
spectra were used in making the NMR assignments.
EI and LSI (3-nitrobenzyl alcohol as liquid matrix)
mode high-resolution mass spectra were obtained by
Dr. N. Davies, University of Tasmania, Australia. Melt-
ing points are uncorrected. Microanalyses were per-
formed at the Campbell Microanalytical Laboratory,
University of Otago, New Zealand.
4.6. 4-Dimethylaminomethylene-4H-pyrano[4,3-b]quino-
line-1,3-dione (4a) and 4-dimethylaminomethylene-6-
methyl-4H-pyrano[4,3-b]quinoline-1,3-dione (4b)
4-Dimethylaminomethylene-4H-pyrano[4,3-b]quinoline-
1,3-dione (4a) and 4-dimethylaminomethylene-6-
methyl-4H-pyrano[4,3-b]quinoline-1,3-dione (4b) were
prepared as reported previously.6 The following diones
were prepared in the same manner.
4.7. 4-Dimethylaminomethylene-7-methoxy-4H-pyr-
ano[4,3-b]quinoline-1,3-dione (4c)
Precursor compounds 3a–d were prepared by adapting a
method for the pyridine analogue.4,6
From 3c, and obtained as a bright yellow solid (95%),
mp273–277 ꢁC (after forming needles >230ꢁC). 1H
NMR (DMSO-d6): d 3.33 (s, 3H, NCH3), 3.62 (s, 3H,
NCH3), 3.94 (s, 3H, ArOCH3), 7.18 (dd, J = 8.9, 1.7Hz,
1H), 7.57 (s, 1H), 8.03 (d, J = 9.0Hz, 1H), 8.97 (s, 2H).
4.1. Ethyl (3-carboxyquinolin-2-yl)acetate (3a)
Ethyl (3-carboxyquinolin-2-yl)acetate (3a), obtained as
a beige solid, mp170–171 ꢁC (from acetonitrile). 1H
NMR (CDCl3): d 1.24 (t, J = 7.1Hz, 3H), 4.20 (q,
J = 7.1Hz, 2H), 4.57 (s, 2H), 7.58 (t, J = 7.6Hz, 1H),
7.82 (t, J = 7.5Hz, 1H), 7.91 (d, J = 8.0Hz, 1H), 8.19
(d, J = 8.5Hz, 1H), 9.00 (s, 1H), 12.28 (br s, 1H).
4.8. 4-Dimethylaminomethylene-4H-pyrano[3,4-b]quino-
xaline-1,3-dione (4d)
From crude 3d, with a ratio of 1g 3d: 0.8mL POCl3:
1.6mL DMF. The reaction mixture was heated, with
moisture exclusion, at 75ꢁC for 16h, then cooled, di-
luted with cold dichloromethane, and kept at ꢀ18ꢁC
for 1h. The brick red solid was filtered and washed
exhaustively, with thorough stirring, with cold dichlo-
romethane to give the dione (22% from 3-chloroquinox-
aline-2-carboxylic acid), mp133–139 ꢁC. 1H NMR
(DMSO-d6): d 3.27 (s, 3H, NCH3), 3.57 (s, 3H,
NCH3), 7.66 (ddd, J = 8.3, 6.6, 1.6Hz, 1H), 7.81–7.92
(m, 2H), 8.04 (d, J = 7.8Hz, 1H), 8.66 (s, 1H,
@HCNMe2). 13C NMR (DMSO-d6): d 45.0 (CH3),
48.3 (CH3), 87.0 (C), 127.2 (CH), 128.3 (CH), 130.3
(CH), 133.3 (C), 133.7 (CH), 139.4 (C), 143.2 (C),
150.3 (C), 157.6 (C), 159.7 (C), 161.1 (CH).
4.2. Ethyl (3-carboxy-8-methylquinolin-2-yl)acetate (3b)
Ethyl (3-carboxy-8-methylquinolin-2-yl)acetate (3b), as
reported.6
4.3. Ethyl (3-carboxy-7-methoxyquinolin-2-yl)acetate
(3c)
Ethyl (3-carboxy-7-methoxyquinolin-2-yl)acetate (3c),
obtained as an orange solid, mp193–195 ꢁC (dec) (from
ethanol). Occasionally, the compound was obtained as a
red oil, which solidified on trituration with cold acetoni-
trile. Recrystallization was not necessary prior to use in
1
the next step. H NMR (CDCl3): d 1.22 (t, J = 7.1Hz,
3H, CO2CH2CH3), 4.02 (s, 3H, ArOCH3), 4.16 (q,
J = 7.1Hz, 2H, CO2CH2CH3), 4.65 (s, 2H, CH2CO2Et),
7.33 (dd, J = 9.1, 1.8Hz, 1H), 7.88 (m, 2H), 9.05 (s, 1H).
4.9. 9-Dimethylaminomethylene-9H-pyrano[4,3-b][1,8]-
naphthyridine-6,8-dione (4e)
From diester 3e, with a ratio of 1g 3e: 0.8mL POCl3:
1.6mL DMF. The reaction mixture was heated, with
moisture exclusion, at 75ꢁC for 16h, then cooled, diluted
with cold dichloromethane, and kept on ice for 1h. The
orange solid was filtered and washed exhaustively, with
thorough stirring, with cold dichloromethane. The mass
of orange dione obtained represented >100% yield. It
was used in further reaction in this state within 24h, since
it decomposed on long standing. 1H NMR (DMSO-d6): d
3.33 (s, 3H, NCH3), 3.62 (s, 3H, NCH3), 7.67 (dd,
J = 7.8, 4.9Hz, 1H), 8.77 (s, 1H), 8.82 (d, J = 8.1Hz,
1H), 9.07 (d, J = 4.9Hz, 1H), 9.15 (s, 1H).
4.4. Ethyl (3-carboxyquinoxalin-2-yl)acetate (3d)
Ethyl (3-carboxyquinoxalin-2-yl)acetate (3d), obtained
as a brown semi-solid, which was used in this state in
the next step.
4.5. Ethyl (3-ethoxycarbonyl[1,8]naphthyridin-2-yl)ace-
tate (3e)
Ethyl (3-ethoxycarbonyl[1,8]naphthyridin-2-yl)acetate
(3e) was prepared from 2-aminonicotinaldehyde and
diethyl 1,3-acetonedicarboxylate by the method re-
ported for the dimethyl analogue,5 as an orange solid,
4.10. 2,6-Dimethyl-1-oxo-1,2-dihydrobenzo[b][1,6]naph-
thyridine-4-carboxylic acid (5c)
1
mp79–80 ꢁC (from ethyl acetate). H NMR (CDCl3):
d 1.20 (t, J = 7.1Hz, 3H, CO2CH2CH3-2), 1.39 (t,
J = 7.1Hz, 3H, CO2CH2CH3-3), 4.13 (q, J = 7.1Hz,
2H, 2-CO2CH2CH3), 4.38 (q, J = 7.1Hz, 2H, 3-
4.10.1. Method (a) for acid formation.3 A solution of
methylamine in tetrahydrofuran (7.0mL, 2M) was

1346
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
added to a suspension of 4b (0.8g) in dimethylformam-
ide (20mL) and the whole was stirred for 16h at room
temperature. The solid was collected by filtration and
washed with cold acetone to give the product as a bright
yellow solid (0.60g, 79%), mp>300 ꢁC (formed cubic
crystals above 290ꢁC). 1H NMR (DMSO-d6): d 2.75
(s, 3H, CH3), 3.67 (s, 3H, NCH3), 7.67 (t, J = 7.7Hz,
1H, H-8), 7.95 (d, J = 6.6Hz, 1H), 8.25 (d, J = 8.1Hz,
1H), 8.83 (s, 1H), 9.52 (s, 1H), 16.03 (s, 1H, COOH).
Anal. Calcd for C15H12N2O3Æ0.2H2O: C, 66.3; H, 4.6;
N, 10.3. Found: C, 66.6; H, 4.4; N, 10.4%.
formamide (15mL) was added triethylamine (2.5mL)
with constant stirring. 2,2,2-Trifluoroethylamine
(0.40g, 4.04mmol) was added and the whole was stirred
at room temperature for 16h. The solid was filtered and
washed with water to give the yellow acid (64%), mp
1
297–300ꢁC (formed needles at 234–235ꢁC). H NMR
(DMSO-d6): d 2.67 (s, 3H, ArCH3), 5.12 (q, J = 9.0Hz,
2H, CH2CF3), 7.63 (t, J = 7.6Hz, 1H, H-8), 7.90 (d,
J = 6.9Hz, 1H, H-7), 8.17 (d, J = 8.2Hz, 1H, H-9), 8.81
(s, 1H, H-3), 9.46 (s, 1H, H-10), 15.91 (br s, 1H, COOH).
The following compounds were made using a similar
procedure.
The following compounds were made using a similar
procedure.
4.15. 2-Ethyl-6-methyl-1-oxo-1,2-dihydrobenzo-
[b][1,6]naphthyridine-4-carboxylic acid (5d)
4.11. 7-Methoxy-2-methyl-1-oxo-1,2-dihydrobenzo-
[b][1,6]naphthyridine-4-carboxylic acid (5w)
From 4b and ethylamine, as for 5f except that the initial
addition of ethylamine was carried out at 0ꢁC and a po-
sitive pressure of nitrogen was maintained throughout,
and obtained as a yellow solid (72%), mp251–253 ꢁC.
1H NMR (DMSO-d6): d 1.30 (t, J = 7.1Hz, 3H,
CH2CH3), 2.65 (s, 3H, ArCH3), 4.12 (q, J = 7.1Hz, 2H,
CH2CH3), 7.59 (t, J = 7.6Hz, 1H, H-8), 7.86 (d,
J = 6.8Hz, 1H, H-7), 8.12 (d, J = 8.3Hz, 1H, H-9), 8.74
(s, 1H, H-3), 9.36 (s, 1H, H-10), 15.89 (s, 1H, COOH).
From 4c and methylamine, as for 5c, and obtained as a
yellow solid (86%), mp>300 ꢁC (from dimethyl sulfox-
1
ide/1,4-dioxane). H NMR (DMSO-d6): d 3.61 (s, 3H,
NCH3), 3.99 (s, 3H, ArOCH3), 7.34 (d, J = 8.0Hz, 1H,
H-8), 7.54 (s, 1H, H-6), 8.21 (d, J = 9.1Hz, 1H, H-9),
8.73 (s, 1H, H-3), 9.31 (s, 1H, H-10), 15.82 (s, 1H,
COOH).
4.12. 7-Methyl-6-oxo-6,7-dihydropyrido[2,3-b][1,6]naph-
thyridine-9-carboxylic acid (5y)
4.16. 2-(2-Hydroxyethyl)-6-methyl-1-oxo-1,2-dihydro-
benzo[b][1,6]naphthyridine-4-carboxylic acid (5g)
From 4e and methylamine, as for 5c except that, after
reaction, the volatiles were removed at reduced pressure
and water was added. The resultant suspension was stir-
red and basified with 10% sodium hydroxide, then acid-
ified with concentrated hydrochloric acid (dropwise) and
the brown solid was filtered to give 5y, mp>300 ꢁC
(from dimethyl sulfoxide/1,4-dioxane). 1H NMR
(DMSO-d6): d 3.64 (s, 3H, NCH3), 7.76 (dd, J = 8.2,
4.2Hz, 1H, H-3), 8.81 (d, J = 8.2Hz, 1H, H-4), 8.85 (s,
1H, H-8), 9.28 (dd, J = 3.9, 1.7Hz, 1H, H-2), 9.58 (s,
1H, H-5), 15.68 (s, 1-H, COOH).
From 4b and ethanolamine, as for 5f, and obtained as a
yellow solid (64%), mp258–261 ꢁC. H NMR (DMSO-
d6): d 2.64 (s, 3H, ArCH3), 3.70 (t, J = 6.2Hz, 2H,
CH2CH2OH), 4.15 (t, J = 5.0Hz, 2H, CH2CH2OH),
7.57 (t, J = 7.6Hz, 1H, H-8), 7.85 (d, J = 6.8Hz, 1H,
H-7), 8.11 (d, J = 8.3Hz, 1H, H-9), 8.62 (s, 1H, H-3),
9.35 (s, 1H, H-10), 15.85 (s, 1H, COOH).
1
4.17. 2-(Ethoxycarbonylmethyl)-6-methyl-1-oxo-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid (5h)
4.13. 2-Methyl-1-oxo-1,2-dihydropyrido[3,4-b]quinoxa-
line-4-carboxylic acid (5z)
From 4b and glycine ethyl ester hydrochloride, as for 5f
except that water was added to the reaction mixture be-
fore the acid was filtered. The product was obtained as a
yellow solid (65%), mp277–280 ꢁC. H NMR (DMSO-
d6): d 1.20 (t, J = 7.1Hz, 3H, CO2CH2CH3), 2.70 (s,
3H, ArCH3), 4.17 (q, J = 7.1Hz, 2H, CO2CH2CH3),
4.97 (s, 2H, CH2CO2Et), 7.64 (t, J = 7.7Hz, 1H, H-8),
7.91 (d, J = 6.9Hz, 1H, H-7), 8.18 (d, J = 8.2Hz, 1H,
H-9), 8.85 (s, 1H, H-3), 9.44 (s, 1H, H-10), 15.89 (br s,
1H, COOH).
1
From 4d and methylamine, as for 5c except that, after
reaction, the volatiles were removed at reduced pressure
to leave the methylamine salt of 5z as a yellow-brown
solid. This was suspended in a small amount of water
and 10% sodium hydroxide was added dropwise, with
stirring, until a solution was obtained. This was acidified
with a minimum amount of concentrated hydrochloric
acid and the solid, which separated was filtered and
washed with water to give the free acid as a yellow solid
(52%), mp>300 ꢁC (from dimethyl sulfoxide/1,4-diox-
ane). 1H NMR (DMSO-d6): d 3.66 (s, 3H, NCH3),
7.97 (t, J = 7.5Hz, 1H), 8.08 (t, J = 7.6Hz, 1H), 8.25–
8.32 (m, 2H), 8.79 (s, 1H), 14.03 (br s, 1H, COOH).
4.18. 2-(3-Ethoxycarbonylpropyl)-6-methyl-1-oxo-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid (5i)
From 4b and ethyl 4-aminobutyrate hydrochloride, as
for 5f except that 1,4-dioxane was used as solvent. After
16h, water was added to the reaction mixture and the
yellow solid was filtered and washed with a little 3%
hydrochloric acid, then with water to give the acid 5i
(59%), mp186–188 ꢁC. This was used in the next step
without further purification but can be recrystallized
4.14. 6-Methyl-1-oxo-2-(2,2,2-trifluoroethyl)-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid (5f)
4.14.1. Method (b) for acid formation. To a stirring sus-
pension of dione 4b (1.00g, 3.54mmol) in N,N-dimethyl-
1
from toluene as a yellow solid. H NMR (CDCl3): d

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1347
1.23 (t, J = 7.1Hz, 3H, CO2CH2CH3), 2.15 (quintet,
J = 7.1Hz, 2H, CH2CH2CH2), 2.41 (t, J = 7.1Hz, 2H,
NCH2CH2CH2), 2.76 (s, 3H, ArCH3), 4.07–4.18 (m,
4H, CO2CH2CH3, NCH2CH2CH2), 7.54 (t, J = 7.6Hz,
1H, H-8), 7.77 (d, J = 6.9Hz, 1H, H-7), 7.87 (d,
J = 8.3Hz, 1H, H-9), 8.57 (s, 1H, H-3), 9.25 (s, 1H, H-
10), 15.93 (s, 1H, COOH). 13C NMR (CDCl3): d 14.1
(CO2CH2CH3), 18.1 (ArCH3), 24.3 (CH2CH2CH2),
31.1 (NCH2CH2CH2), 49.3 (NCH2CH2CH2), 60.7
(CO2CH2CH3), 105.3 (C-4), 118.9 (C-10a), 126.4 (C-
9a), 127.4 (CH, C-8), 127.6 (CH, C-9), 134.3 (CH, C-
7), 134.8 (C-6), 141.3 (CH, C-10), 145.2 (CH, C-3),
146.5 (C-5a), 148.5 (C-4a), 161.7 (C-1), 166.0 (COOH),
172.1 (CO2Et).
2H), 4.02 (t, J = 7.3Hz, 2H), 7.54 (t, J = 7.7Hz, 1H,
H-8), 7.81 (d, J = 7.0Hz, 1H, H-7), 8.04 (d, J = 8.2Hz,
1H, H-9), 8.82 (s, 1H, H-3), 9.35 (s, 1H, H-10).
4.23. 2-[2-(1H-Indol-3-yl)ethyl]-6-methyl-1-oxo-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid (5n)
From 4b and tryptamine, as for 5f, and obtained as a
1
yellow solid (91%), mp>300 ꢁC. H NMR (DMSO-d6):
d 2.69 (s, 3H, ArCH3), 3.14 (t, J = 7.2Hz, 2H,
CH2CH2Indole), 4.36 (t, J = 7.1Hz, 2H, CH2CH2-
Indole), 6.91 (t, J = 7.4Hz, 1H), 7.02 (t, J = 7.5Hz,
1H), 7.14 (s, 1H, H-20), 7.30 (d, J = 8.0Hz, 1H), 7.58–
7.65 (m, 2H), 7.90 (d, J = 6.8Hz, 1H), 8.19 (d,
J = 7.9Hz, 1H), 8.54 (s, 1H, H-3), 9.49 (s, 1H, H-10),
10.83 (s, 1H, NH), 15.91 (s, 1H, COOH).
4.19. 2-(3,4-Dimethoxybenzyl)-6-methyl-1-oxo-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid (5j)
4.24. 2-Hydroxy-6-methyl-1-oxo-1,2-dihydro-
benzo[b][1,6]naphthyridine-4-carboxylic acid (5p)
From 4b and veratrylamine, as for 5f, and obtained as a
yellow solid (77%), mp256–257 ꢁC. H NMR (DMSO-
1
d6): d 2.70 (s, 3H, ArCH3), 3.69 (s, 3H, OCH3), 3.70
(s, 3H, OCH3), 5.25 (s, 2H, CH2Ph), 6.88–6.97 (m,
2H, H-50, H-60), 7.07 (s, 1H, H-20), 7.63 (t, J = 7.6Hz,
1H, H-8), 7.90 (d, J = 7.0Hz, 1H, H-7), 8.19 (d,
J = 8.2Hz, 1H, H-9), 8.81 (s, 1H, H-3), 9.49 (s, 1H, H-
10), 15.97 (br s, 1H, COOH).
From 4b and hydroxylamine hydrochloride, as for 5f
except that, after reaction, 10% sodium hydroxide was
added dropwise until a solution was obtained. The
phase was then made acidic with concentrated hydro-
chloric acid (dropwise) and the resultant brown solid
was filtered to give the acid 5p (64%), mp262–264 ꢁC
1
(twice from ethanol). H NMR (DMSO-d6, 100ꢁC): d
4.20. 2-[2-(3,4-Dimethoxyphenyl)ethyl]-6-methyl-1-oxo-
1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid
(5k)
2.66 (s, 3H, ArCH3), 7.61 (t, J = 7.6Hz, 1H, H-8), 7.88
(d, J = 6.8Hz, 1H, H-7), 8.16 (d, J = 8.2Hz, 1H, H-9),
8.63 (s, 1H, H-3), 9.45 (s, 1H, H-10), 12.29 (br s, 1H,
NOH), 15.89 (s, 1H, COOH). 13C NMR (DMSO-d6,
100ꢁC): d 17.2 (ArCH3), 103.2 (C-4), 119.5 (C-10a),
126.0 (C-9a), 127.3 (CH, C-8), 127.9 (CH, C-9), 133.9
(C-6), 134.3 (CH, C-7), 140.9 (CH, C-10), 143.1 (CH,
C-3), 146.1 (C-5a), 147.6 (C-4a), 158.1 (C-1), 164.4
(COOH). Anal. Calcd for C14H10N2O4: C, 62.2; H,
3.7; N, 10.4. Found: C, 62.0; H, 3.4; N, 10.3%.
From 4b and 3,4-dimethoxyphenethylamine, as for 5f,
and obtained as a yellow solid (79%), mp280–282 ꢁC.
1H NMR (DMSO-d6): d 2.70 (s, 3H, ArCH3), 2.94 (t,
J = 7.3Hz, 2H, CH2CH2Ph), 3.66 (s, 3H, OCH3), 3.67
(s, 3H, OCH3), 4.31 (t, J = 7.2Hz, 2H, CH2CH2Ph),
6.71 (d, J = 8.1Hz, 1H, H-50), 6.80 (d, J = 8.1Hz, 1H,
H-60), 6.91 (s, 1H, H-20), 7.64 (t, J = 7.8Hz, 1H, H-8),
7.92 (d, J = 6.8Hz, 1H, H-7), 8.21 (d, J = 8.4Hz, 1H,
H-9), 8.67 (s, 1H, H-3), 9.48 (s, 1H, H-10), 15.89 (br s,
1H, COOH).
4.25. 6-Methyl-1-oxo-2-phenyl-1,2-dihydro-
benzo[b][1,6]naphthyridine-4-carboxylic acid (5s)
From 4b and aniline (10molequiv), as for 5f except that
the product when filtered was washed thoroughly with
acetone. The acid was a lemon colored solid (41%),
mp>310 ꢁC, which was used in the next stepwithout
further purification but can be recrystallized from 1,4-
4.21. 6-Methyl-1-oxo-2-(pyridin-2-yl)methyl-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid (5l)
From 4b and 2-aminomethylpyridine, as for 5f, and ob-
1
1
tained as a yellow solid (57%), mp>300 ꢁC. H NMR
dioxane. H NMR (DMSO-d6): d 2.73 (s, 3H, ArCH3),
(DMSO-d6): d 2.72 (s, 3H, ArCH3), 5.47 (s, 2H,
CH2Pyr), 7.27 (dd, J = 7.0, 5.2Hz, 1H), 7.44 (d,
J = 7.8Hz, 1H), 7.63 (t, J = 7.6Hz, 1H), 7.78 (t,
J = 7.7Hz, 1H), 7.92 (d, J = 6.7Hz, 1H), 8.18 (d, J =
8.3Hz, 1H), 8.44 (d, J = 4.6Hz, 1H), 8.90 (s, 1H, H-3),
9.43 (s, 1H, H-10), 15.98 (br s, 1H, COOH).
7.51–7.59 (m, 5H, Ph), 7.66 (t, J = 7.6Hz, 1H, H-8),
7.95 (d, J = 6.9Hz, 1H, H-7), 8.23 (d, J = 8.3Hz, 1H,
H-9), 8.46 (s, 1H, H-3), 9.51 (s, 1H, H-10), 15.99 (br s,
1H, COOH). Anal. Calcd for C20H14N2O3Æ0.4H2O: C,
71.2; H, 4.4; N, 8.3. Found: C, 71.3; H, 4.0; N, 8.3%.
The filtrate was taken to dryness at reduced pressure,
water was added, and the resultant yellow solid was fil-
tered and washed with water to give N,N-dimethyl-2-[2-
(phenylamino)vinyl]-8-methylquinoline-3-carboxamide
(7a) (32%), mp143–146 ꢁC [from light petroleum (bp
90–110ꢁC)]. 1H NMR (DMSO-d6): d 2.79 (s, 6H,
ArCH3, NCH3), 3.06 (s, 3H, NCH3), 5.31 (d,
J = 8.5Hz, 1H, HC@), 6.93 (t, J = 7.3Hz, 1H, H-40),
7.17 (d, J = 8.0Hz, 2H, H-20, H-60), 7.30–7.38 (m, 3H,
H-6, H-30, H-50), 7.52–7.62 (m, 2H, @CH, H-7), 7.69
4.22. 6-Methyl-1-oxo-2-[3-(2-oxopyrrolidin-1-yl)propyl]-
1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxylic acid
(5m)
From 4b and N-(3-aminopropyl)-2-pyrrolidinone, as for
5f, and obtained as a yellow solid (0.43g, 64%), mp226–
1
228ꢁC. H NMR (DMSO-d6+trace CF3CO2H): d 1.84–
1.96 (m, 4H), 2.20 (t, J = 8.0Hz, 2H), 2.56 (s, 3H,
ArCH3), 3.25 (t, J = 6.8Hz, 2H), 3.34 (t, J = 7.0Hz,

1348
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
(d, J = 7.9Hz, 1H, H-5), 8.05 (s, 1H, H-4), 11.95 (d,
J = 11.7Hz, 1H, NH—exchanges with added D2O).
13C NMR (DMSO-d6): d 18.8 (ArCH3), 34.3 (NCH3),
38.2 (NCH3), 94.5 (HC@), 115.0 (2 · CH, C-20, C-60),
121.6 (CH, C-40), 124.0 (C-4a), 125.0 (CH, C-6), 126.1
(CH, C-5), 129.5 (C-3), 129.9 (2 · CH, C-30, C-50),
130.5 (CH, C-7), 133.5 (CH, C-4), 133.7 (C-8), 136.4
(@CH), 141.5 (C-10), 145.3 (C-8a), 153.8 (C-2), 168.4
(CONMe2). HRMS (EI) calcd for C21H21N3O:
331.1686. Found: 331.1686.
ethoxide [prepared from sodium (25mg, 1.09mmol) in
ethanol (10mL)]. The volatiles were removed at reduced
pressure, N,N-dimethylformamide (20mL) was added to
the residue, and the whole was heated at 110ꢁC, with
stirring, for 5min. Iodomethane (1mL) was added and
stirring was continued at the same temperature for 1h
(dissolution occurred during this time). The solution
was evaporated to dryness at reduced pressure and ice-
water was added to the brown residue. The phase was
made acidic with concd hydrochloric acid and the resul-
tant yellow solid was filtered and washed with water to
give the methoxy acid 5q (0.23g, 84%), mp277–278 ꢁC
(from N,N-dimethylformamide as yellow needles). 1H
NMR (DMSO-d6): d 2.70 (s, 3H, ArCH3), 4.09 (s, 3H,
OCH3), 7.66 (t, J = 7.7Hz, 1H, H-8), 7.93 (d,
J = 6.9Hz, 1H, H-7), 8.20 (d, J = 8.2Hz, 1H, H-9),
8.90 (s, 1H, H-3), 9.51 (s, 1H, H-10), 15.96 (s, 1H,
COOH).
4.26. 6-Methyl-1-oxo-2-(4-fluorophenyl)-1,2-dihydro-
benzo[b][1,6]naphthyridine-4-carboxylic acid (5t)
From 4b and 4-fluoroaniline (10molequiv), as for 5s.
The first filtered product was a triethylamine salt of
the target acid. This was dissolved in hot 5% sodium
hydroxide, filtered, and the filtrate was cooled and acid-
ified with concentrated hydrochloric acid to give the acid
1
as a yellow solid (26%). H NMR (DMSO-d6): d 2.75
4.29. 2-Acetoxy-6-methyl-1-oxo-1,2-dihydro-
benzo[b][1,6]naphthyridine-4-carboxylic acid (5ff)
(s, 3H, CH3), 7.38–7.43 (m, 2H), 7.60–7.70 (m, 3H),
7.95 (d, J = 6.0Hz, 1H), 8.25 (d, J = 8.4Hz, 1H), 8.48
(s, 1H), 9.53 (s, 1H).
A suspension of the pulverized hydroxylacid 5p (0.23g,
0.85mmol), acetic acid (1.5mL), and acetic anhydride
(12mL) was heated, with stirring, at 60ꢁC for 2h. The
reaction mixture was cooled, filtered and washed with
acetone to give the acetoxylacid 5ff as a yellow solid
(0.22g, 83%), which contained <10% starting hydroxyl-
acid 5p. Recrystallization from acetonitrile gave 5ff as
Addition of water to the first filtrate gave a yellow-green
solid, which was recrystallized twice from methanol to
give N,N-dimethyl-2-[2-((4-fluorophenyl)amino)vinyl]-
8-methylquinoline-3-carboxamide (7b), mp172–173 ꢁC
1
after changing form ca. 100ꢁC. H NMR (DMSO-d6):
1
d 2.78 (s, 3H, CH3) 2.79 and 3.06 [2 · s, 6H,
N(CH3)2], 5.28 (d, J = 8.5Hz, 1H), 7.13–7.20 (m, 4H),
7.36 (t, J = 7.4Hz, 1H), 7.50 (dd, J = 11.7, 8.5Hz, 1H),
7.61 (d, J = 6.8Hz, 1H), 7.70 (d, J = 7.9Hz, 1H), 8.06
(s, 1H), 11.96 (d, J = 11.7Hz, 1H).
yellow needles, mp264–265 ꢁC. H NMR (DMSO-d6):
d 2.40 (s, 3H, COCH3), 2.73 (s, 3H, ArCH3), 7.69 (t,
J = 7.6Hz, 1H, H-8), 7.97 (d, J = 6.9Hz, 1H, H-7),
8.25 (d, J = 8.2Hz, 1H, H-9), 9.08 (s, 1H, H-3), 9.56
(s, 1H, H-10), 15.99 (s, 1H, COOH).
4.27. 6-Methyl-1-oxo-2-[4-(4,4,5,5-tetramethyl[1,3,2]-
dioxaborolan-2-yl)phenyl]-1,2-dihydrobenzo[b][1,6]naph-
thyridine-4-carboxylic acid (5ee)
4.30. N-[2-(Dimethylamino)ethyl]-2-(3-ethoxycarbonyl)-
propyl-6-methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyr-
idine-4-carboxamide (2i)
From 4b and 2molequiv of 4-(4,4,5,5-tetrameth-
yl[1,3,2]dioxaborolan-2-yl)aniline, as for 5f. A solution
formed slowly and, after 16h, the volume was reduced
to ca 1/3 at reduced pressure, and the whole was cooled
on ice. The solid which separated was filtered off,
washed with cold toluene and the recrystallized from tol-
uene to give the acid as a yellow solid (20%),
mp>300 ꢁC. 1H NMR (CDCl3): d 1.36 (s, 12H,
4 · CH3), 2.87 (s, 3H, ArCH3), 7.46 (d, J = 8.0Hz, 2H,
ArH), 7.61 (t, J = 7.6Hz, 1H, H-8), 7.85 (d, J = 6.8Hz,
1H, H-7), 7.95–8.00 (m, 3H, H-9, ArH), 8.72 (s, 1H,
H-3), 9.42 (s, 1H, H-10), 16.16 (s, 1H, COOH).
4.30.1. Method (a) for formation of carboxamides. Acid
5i (0.40g, 1.09mmol) was heated under reflux in thionyl
chloride (20mL) for 5h. The excess of thionyl chloride
was removed at reduced pressure and a solution of
N,N-dimethylethylenediamine (0.5mL, 4.56mmol) in
dichloromethane (20mL) was added to the residue.
The resulting solution was stirred at room temperature
for 16h and the solution was washed with 10% sodium
hydroxide and water (·2). The solvent was removed at
reduced pressure to give the product as a yellow solid
(0.35g, 74%), mp130–132 ꢁC [from toluene/light petro-
leum (bp90–120 ꢁC)]. 1H NMR (CDCl3): d 1.23 (t,
J = 7.1Hz,
3H,
CO2CH2CH3),
2.15
(quintet,
The filtrate from the reaction mixture (containing DMF,
triethylamine, and toluene) was taken to dryness at re-
duced pressure, and the residue was recrystallized from
toluene to give the starting aniline as a yellow solid
(45% recovery).
J = 7.2Hz, 2H, CH2CH2CH2), 2.40 (t, J = 7.2Hz, 2H,
NCH2CH2CH2), 2.49 [s, 6H, N(CH3)2], 2.84–2.89 (m,
5H, ArCH3, CH2CH2NMe2), 3.84 (q, J = 6.2Hz, 2H,
CH2CH2NMe2), 4.07–4.17 (m, 4H, CO2CH2CH3,
NCH2CH2CH2), 7.49 (t, J = 7.6Hz, 1H, H-8), 7.73 (d,
J = 6.9Hz, 1H, H-7), 7.86 (d, J = 8.2Hz, 1H, H-9),
8.57 (s, 1H, H-3), 9.27 (s, 1H, H-10), 11.17 (br s, 1H,
CONH). 13C NMR (CDCl3): d 14.2 (CO2CH2 CH3),
18.6 (ArCH3), 24.5 (CH2CH2CH2), 31.2 (NCH2CH2-
CH2), 36.8 (CH2CH2NMe2), 44.7 [N(CH3)2], 48.9
(NCH2CH2CH2), 58.0 (CH2CH2NMe2), 60.6 (CO2-
4.28. 2-Methoxy-6-methyl-1-oxo-1,2-dihydro-
benzo[b][1,6]naphthyridine-4-carboxylic acid (5q)
To a suspension of the hydroxylacid 5p (0.26g,
0.96mmol) in hot ethanol (50mL) was added sodium

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1349
CH2CH3), 109.5 (C-4), 119.4 (C-10a), 126.0 (C-9a),
126.8 (CH, C-8), 127.4 (CH, C-9), 133.1 (CH, C-7),
135.9 (C-6), 140.1 (CH, C-10), 142.9 (CH, C-3), 148.2
(C-5a), 148.6 (C-4a), 162.4 (C-1), 164.9 (CONH), 172.3
(CO2Et). Anal. Calcd for C24H30N4O4Æ0.75H2O: C,
63.8; H, 7.0; N, 12.4. Found: C, 63.6; H, 7.0; N,
12.4%.
N(CH3)2], 2.70 (t, J = 6.4Hz, 2H, CH2CH2NMe2),
2.88 (s, 3H, ArCH3), 3.77 (q, J = 6.1Hz, 2H,
CH2CH2NMe2), 7.43–7.55 (m, 6H, H-8, Ph), 7.75 (d,
J = 6.9Hz, 1H, H-7), 7.88 (d, J = 8.1Hz, 1H, H-9),
8.71 (s, 1H, H-3), 9.32 (s, 1H, H-10), 11.06 (br s, 1H,
CONH). 13C NMR (CDCl3): d 18.6 (ArCH3), 37.5
(CH2CH2NMe2), 45.3 [N(CH3)2], 58.6 (CH2CH2NMe2),
110.0 (C-4), 119.9 (C-10a), 126.2 (C-9a), 126.7 (2 · CH,
Ph), 126.8 (CH, C-8), 127.4 (CH, C-9), 128.8 (CH, C-40),
129.5 (2 · CH, Ph), 133.1 (CH, C-7), 136.1 (C-6), 140.1
(C-10), 140.5 (CH, C-10), 143.4 (CH, C-3), 148.4 (C-5a),
148.9 (C-4a), 162.2 (C-1), 164.6 (CONH). Anal. Calcd
for C24H24N4O2: C, 72.0; H, 6.0; N, 14.0. Found: C,
71.8; H, 6.0; N, 13.8%.
The following compounds were made using a similar
procedure.
4.31. N-[2-(Dimethylamino)ethyl]-2-hydroxy-6-methyl-1-
oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxam-
ide (2p)
From 5p, with a reflux time of 15min. After reaction
with N,N-dimethylethylenediamine (4.2molequiv) for
16h, the volatiles were removed at reduced pressure
and the resultant red solid was recrystallized from moist
ethanol to give the amide 2p as orange needles (66%),
4.34. N-[2-(Dimethylamino)ethyl]-2-(4-fluorophenyl)-6-
methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (2t)
From acid 5t, with a reflux time of 30min, and obtained
as pale yellow needles (88%), mp 219–220ꢁC (from ace-
1
mp210–211 ꢁC. H NMR (DMSO-d6, 70ꢁC): d 2.24 [s,
1
6H, N(CH3)2], 2.56 (t, J = 6.2Hz, 2H, CH2CH2NMe2),
2.79 (s, 3H, ArCH3), 3.58 (q, J = 6.0Hz, 2H,
CH2CH2NMe2), 7.53 (t, J = 7.6Hz, 1H, H-8), 7.80 (d,
J = 6.8Hz, 1H, H-7), 8.03 (d, J = 8.1Hz, 1H, H-9),
8.56 (s, 1H, H-3), 9.29 (s, 1H, H-10), 10.54 (br s, 1H,
CONH). 13C NMR (DMSO-d6, 70ꢁC): d 17.8 (ArCH3),
tonitrile). H NMR (CDCl3): d 2.45 [s, 6H, N(CH3)2],
2.82 [t, J = 6.3Hz, 2H, CH2N(CH3)2], 2.87 (s, 3H,
CH3), 3.83 (q, J = 6.4Hz, 2H, CONHCH2), 7.18–7.25
(m, 2H), 7.42–7.55 (m, 3H), 7.76 (d, J = 7.0Hz, 1H),
7.89 (d, J = 8.1Hz, 1H), 8.65 (s, 1H, H-3), 9.30 (s, 1H,
H-10), 11.14 (br s, 1H, CONH). 13C NMR (CDCl3): d
18.4 (C6–CH3), 35.7 (CH2), 43.7 [N(CH3)2], 56.9
(CH2), 109.1 (C), 116.15 (d, J = 23.1Hz, CH, C-30,50),
119.2 (C), 125.8 (C), 126.8 (CH), 127.0 (CH), 128.16
(d, J = 8.5Hz, CH, C-20,60), 133.2 (CH), 135.5 (C),
140.3 (CH), 142.8 (CH), 147.8 (C), 148.0 (C), 161.8
(C), 162.0 (d, J = 244.5Hz, C-40), 164.8 (C). Anal. Calcd
for C24H23FN4O2: C, 68.9; H, 5.5; N, 13.4. Found: C,
68.9; H, 5.6; N, 13.4%.
37.1
(CH2CH2NMe2),
45.0
[N(CH3)2],
58.5
(CH2CH2NMe2), 107.7 (C-4), 119.8 (C-10a), 125.4 (C-
9a), 126.8 (CH, C-8), 127.5 (CH, C-9), 133.1 (CH, C-
7), 135.4 (C-6), 139.5 (CH, C-10), 141.2 (CH, C-3),
147.4 (C-4a), 147.6 (C-5a), 158.4 (C-1), 163.0 (CONH).
Anal. Calcd for C18H20N4O3Æ0.5H2O: C, 61.9; H, 6.1; N,
16.0. Found: C, 61.5; H, 6.1; N, 15.7%.
4.32. N-[2-(Dimethylamino)ethyl]-2-methoxy-6-methyl-
1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbox-
amide (2q)
4.35. N-[2-(Dimethylamino)ethyl]-6-chloro-7-methoxy-2-
methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (2x)
From acid 5q, with a reflux time of 15min, and obtained
as an orange solid (77%), mp163–164 ꢁC (from acetoni-
From acid 5w, with a reflux time of 5h, and obtained as
a brown solid (73%), mp209–212 ꢁC (from acetonitrile).
1H NMR (CDCl3): d 2.32 [s, 6H, N(CH3)2], 2.69 (t,
J = 6.8Hz, 2H, CH2CH2NMe2), 3.69–3.77 (m, 5H,
CH2CH2NMe2, NCH3), 4.14 (s, 3H, ArOCH3), 7.45
(d, J = 9.2Hz, 1H, H-8), 7.97 (d, J = 9.2Hz, 1H, H-9),
8.63 (s, 1H, H-3), 9.24 (s, 1H, H-10), 11.17 (br s, 1H,
CONH). 13C NMR (CDCl3): d 37.2 (NCH3), 37.9
(CH2CH2NMe2), 45.6 [N(CH3)2], 57.0 (ArOCH3), 58.9
(CH2CH2NMe2), 109.4 (C-4), 114.4 (CH, C-8), 116.6
(C-6), 118.2 (C-10a), 121.9 (C-9a), 129.1 (CH, C-9),
139.9 (CH, C-10), 144.5 (CH, C-3), 146.1 (C-5a), 150.5
(C-4a), 158.3 (C-7), 162.6 (C-1), 164.3 (CONH). Anal.
Calcd for C19H21ClN4O3: C, 58.7; H, 5.4; N, 14.4.
Found: C, 58.3; H, 5.4; N, 14.3%.
1
trile). H NMR (CDCl3): d 2.33 [s, 6H, N(CH3)2], 2.67
(t, J = 6.4Hz, 2H, CH2CH2NMe2), 2.82 (s, 3H, ArCH3),
3.74 (q, J = 6.1Hz, 2H, CH2CH2NMe2), 4.14 (s, 3H,
OCH3), 7.48 (dd, J = 8.2, 7.1Hz, 1H, H-8), 7.71 (d,
J = 6.9Hz, 1H, H-7), 7.82 (d, J = 8.3Hz, 1H, H-9),
8.76 (s, 1H, H-3), 9.25 (s, 1H, H-10), 10.88 (br s, 1H,
CONH). 13C NMR (CDCl3): d 18.2 (ArCH3), 37.1
(CH2CH2NMe2), 44.9 [N(CH3)2], 58.2 (CH2CH2NMe2),
64.7 (OCH3), 109.3 (C-4), 120.1 (C-10a), 125.3 (C-9a),
126.8 (CH, C-8), 126.9 (CH, C-9), 132.8 (CH, C-7),
135.7 (C-6), 139.5 (CH, C-10), 139.7 (CH, C-3), 147.3
(C-4a), 147.9 (C-5a), 158.0 (C-1), 163.4 (CONH). Anal.
Calcd for C19H22N4O3: C, 64.4; H, 6.3; N, 15.8. Found:
C, 64.0; H, 6.2; N, 15.7%.
4.33. N-[2-(Dimethylamino)ethyl]-6-methyl-2-phenyl-1-
oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxam-
ide (2s)
4.36. N-[2-(Dimethylamino)ethyl]-7-methyl-6-oxo-6,7-
dihydropyrido[2,3-b][1,6]naphthyridine-9-carboxamide
(2y)
From acid 5s, with a reflux time of 30min, and obtained
as pale yellow needles (55%), mp 199–201ꢁC (from
From acid 5y, with a reflux time of 1.5h (complete
dissolution did not occur). The crude amide was added
to a short silica column. This was first eluted with
methanol). 1H NMR (CDCl3):
d 2.35 [s, 6H,

1350
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
dichloromethane/methanol (19:1) and then with dichlo-
romethane/methanol (1:1), which furnished the amide
as a yellow solid (17%), mp218–221 ꢁC (from acetoni-
(CONMe2). Anal. Calcd for C20H22N4O3: C, 65.6; H,
6.1; N, 15.3. Found: C, 65.8; H, 6.0; N, 15.3%.
1
trile). H NMR (CDCl3): d 2.41 [s, 6H, N(CH3)2], 2.74
4.39. (S)-N-[2-(1-Dimethylamino)propyl]-2,6-dimethyl-1-
oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxam-
ide (2bb)
(t, J = 6.6Hz, 2H, CH2CH2NMe2), 3.70 (s, 3H, ArCH3),
3.76 (q, J = 6.3Hz, 2H, CH2CH2NMe2), 7.57 (dd,
J = 8.2, 4.2Hz, 1H, H-3), 8.40 (dd, J = 8.3, 2.0Hz, 1H,
H-4), 8.68 (s, 1H, H-8), 9.27 (dd, J = 4.2, 2.0Hz, 1H,
H-2), 9.36 (s, 1H, H-5), 10.95 (br s, 1H, CONH). 13C
NMR (CDCl3): d 37.0 (NCH3), 37.3 (CH2CH2NMe2),
45.1 [N(CH3)2], 58.2 (CH2CH2NMe2), 109.1 (C-9),
120.1 (C), 120.4 (C), 122.1 (CH, C-3), 138.3 (CH, C-
4), 141.4 (CH, C-5), 145.0 (CH, C-8), 152.1 (C-9a),
155.2 (C-10a), 157.2 (CH, C-2), 161.9 (C-6), 163.7
(CONH). Anal. Calcd for C17H19N5O2ÆH2O: C, 59.5;
H, 6.2; N, 20.4. Found: C, 59.6; H, 5.7; N,
20.3%.
From acid 5c, with a reflux time of 45min. To a
suspension in dichloromethane of the residue from re-
moval of the thionyl chloride was added a solution of
(S)-N1,N1-dimethylpropane-1,2-diamine dihydrochlo-
ride (2.2molequiv) and triethylamine (2.2molequiv) in
dichloromethane. The standard reaction and workup
gave the amide (38%) as a light brown solid, mp205–
209ꢁC (from acetonitrile). 1H NMR (DMSO-d6,
100ꢁC): d 1.46 (d, J = 6.6Hz, 3H, CHCH3), 2.81 (s,
3H, ArCH3), 2.84 [s, 6H, N(CH3)2], 3.31 (d,
J = 6.8Hz, 2H, CH2NMe2), 3.64 (s, 3H, NCH3), 4.64
(quintet, J = 6.9Hz, 1H, CHCH3), 7.57 (t, J = 7.6Hz,
1H, H-8), 7.84 (d, J = 6.0Hz, 1H, H-7), 8.08 (d,
J = 8.1Hz, 1H, H-9), 8.60 (s, 1H, H-3), 9.31 (s, 1H, H-
10), 10.75 (br s, 1H, CONH). 13C NMR (DMSO-d6,
100ꢁC): d 18.5 (ArCH3), 19.6 (CHCH3), 36.6 (NCH3),
43.4 [N(CH3)2], 62.4 (CH2NMe2), 108.4 (C-4),
119.2 (C-10a), 125.9 (C-9a), 126.8 (CH, C-8), 127.7
(CH, C-9), 133.3 (CH, C-7), 135.2 (C-6), 139.8 (CH,
C-10), 144.9 (CH, C-3), 147.7 (C-5a), 148.7 (C-4a),
162.0 (C-1), 164.2 (CONH). Carbon CHCH3 was not
observed.
4.37. N-[2-(Dimethylamino)ethyl]-2-methyl-1-oxo-1,2-
dihydropyrido[3,4-b]quinoxaline-4-carboxamide (2z)
From acid 5z, with a reflux time of 45min, and
obtained as golden flakes (47%), mp215–218 ꢁC (after
1
forming needles >109ꢁC) (from acetonitrile). H NMR
(CDCl3): d 2.41 [s, 6H, N(CH3)2], 2.65 (t, J =
6.1Hz, 2H, CH2CH2NMe2), 3.67 (q, J = 5.7Hz, 2H,
CH2CH2NMe2), 3.75 (s, 3H, NCH3), 7.80–7.86 (m,
1H), 7.88–7.95 (m, 1H), 8.08 (d, J = 8.3Hz, 1H),
8.38 (d, J = 8.1Hz, 1H), 8.63 (s, 1H), 10.61 (br s, 1H).
13C NMR (CDCl3): d 37.1 (CH2), 37.5 (CH3), 44.9
[N(CH3)2], 57.5 (CH2), 108.0 (C), 127.9 (CH),
130.4 (CH), 130.5 (CH), 133.3 (CH), 136.7 (C), 141.4
(C), 142.2 (C), 143.5 (CH), 144.9 (C), 160.9 (C),
163.2 (C).
The hydrochloride had mp241–245 ꢁC after forming
needles >200ꢁC (yellow powder from acetonitrile).
Anal. Calcd for C20H24N4O2ÆHCl: C, 61.8; H, 6.5; N,
14.4. Found: C, 61.5; H, 6.2; N, 14.6%.
The yellow hydrochloride had mp218–221 ꢁC (from
ethanol). Anal. Calcd for C17H19N5O2ÆHClÆ0.25H2O:
C, 55.7; H, 5.6; N, 19.1. Found: C, 55.9; H, 5.4; N,
19.1%.
4.40. (R)-N-[2-(1-Dimethylamino)propyl]-2,6-dimethyl-1-
oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxam-
ide (2cc)
From acid 5c, thionyl chloride, (R)-N1,N1-dimethylpro-
pane-1,2-diamine dihydrochloride and triethylamine as
for 2bb. The amide was obtained as a yellow solid
(57%), mp195–199 ꢁC (from acetonitrile). 1H NMR
(DMSO-d6, 100ꢁC): d 1.28 (d, J = 6.5Hz, 3H, CHCH3),
2.20 [s, 6H, N(CH3)2], 2.34 (dd, J = 12.2, 6.4Hz, 1H,
CHNMe2), 2.54 (dd, J = 12.2, 7.4Hz, 1H, CHNMe2),
2.79 (s, 3H, ArCH3), 3.62 (s, 3H, NCH3), 4.31 (quintet,
J = 6.9Hz, 1H, CHCH3), 7.54 (t, J = 7.6Hz, 1H, H-8),
7.81 (d, J = 6.8Hz, 1H, H-7), 8.05 (d, J = 8.3Hz, 1H,
H-9), 8.56 (s, 1H, H-3), 9.27 (s, 1H, H-10), 10.46 (br
d, J = 6.9Hz, 1H, CONH). 13C NMR (DMSO-d6,
100ꢁC): d 18.1 (ArCH3), 19.7 (CHCH3), 36.5 (NCH3),
43.2 (CHCH3), 45.5 [N(CH3)2], 65.1 (CH2NMe2),
108.9 (C-4), 119.3 (C-10a), 125.8 (C-9a), 126.6 (CH, C-
8), 127.7 (CH, C-9), 133.1 (CH, C-7), 135.2 (C-6),
139.6 (CH, C-10), 144.6 (CH, C-3), 147.7 (C-5a), 148.9
(C-4a), 162.0 (C-1), 162.9 (CONH).
4.38. (S)-N-[1-((Dimethylamino)carbonyl)ethyl]-2,6-
dimethyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (2aa)
From acid 5c, with a reflux time of 45min. To the
residue from removal of the thionyl chloride was added
triethylamine (2.2molequiv) in dichloromethane fol-
lowed by (S)-2-amino-N,N-dimethylpropionamide (1.1
molequiv) in dichloromethane. The standard reaction
and workupgave the amide (88%) as yellow needles,
1
mp277–280 ꢁC (from ethanol). H NMR (DMSO-d6,
100ꢁC): d 1.42 (d, J = 6.8Hz, 3H, CHCH3), 2.81 (s,
3H, ArCH3), 2.99 [br s, 6H, N(CH3)2], 3.62 (s, 3H,
NCH3), 5.21 (quintet, J = 7.1Hz, 1H, CHCH3), 7.53
(t, J = 7.6Hz, 1H, H-8), 7.79 (d, J = 6.8Hz, 1H, H-7),
8.03 (d, J = 8.2Hz, 1H, H-9), 8.55 (s, 1H, H-3), 9.26
(s, 1H, H-10), 10.84 (br d, J = 7.7Hz, 1H, CONH).
13C NMR (DMSO-d6, 100ꢁC): d 18.2 (ArCH3), 18.4
(CHCH3), 36.1 [br s, N(CH3)2], 36.5 (NCH3), 44.6
(CHCH3), 108.6 (C-4), 119.1 (C-10a), 125.8 (C-9a),
126.6 (CH, C-8), 127.5 (CH, C-9), 133.0 (CH, C-7),
135.7 (C-6), 139.6 (CH, C-10), 144.7 (CH, C-3), 147.8
(C-5a), 148.7 (C-4a), 162.0 (C-1), 162.8 (CONH), 172.1
The hydrochloride had mp232–240 ꢁC after changing
form at 200ꢁC and forming needles >205ꢁC [yellow
solid from acetonitrile (hygroscopic)]. Anal. Calcd for
C20H24N4O2ÆHCl: C, 61.8; H, 6.5; N, 14.4. Found: C,
62.1; H, 6.4; N, 14.4%.

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1351
4.41. N-[2-(Methylamino)ethyl]-2,6-dimethyl-1-oxo-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxamide (2dd)
(d, J = 6.9Hz, 1H, H-7), 7.65 (d, J = 8.2Hz, 1H, H-
9), 8.48 (s, 1H, H-3), 8.99 (s, 1H, H-10), 10.73 (br t,
J = 5.1Hz, 1H, CONH). 13C NMR (CDCl3): d 14.4
(CH2CH3), 18.3 (ArCH3), 37.5 (CH2CH2NMe2), 44.6
(CH2CH3), 45.3 [N(CH3)2], 58.7 (CH2CH2NMe2),
109.5 (C-4), 119.2 (C-10a), 125.5 (C-9a), 126.2 (CH, C-
8), 127.1 (CH, C-9), 132.4 (CH, C-7), 135.6 (C-6),
139.4 (CH, C-10), 142.4 (CH, C-3), 147.7 (C-5a), 148.4
(C-4a), 161.9 (C-1), 164.3 (CONH). Anal. Calcd for
C20H24N4O2: C, 68.2; H, 6.9; N, 15.9. Found: C, 68.5;
H, 6.8; N, 16.1%.
Acid 5c (0.5g) was taken to crude acid chloride with
thionyl chloride. A suspension of this and 2-chloroethyl-
amine hydrochloride (0.54g) in dichloromethane
(10mL) was stirred and cooled on ice. Triethylamine
(3mL) was added and the mixture was stirred at 20ꢁC
overnight (solid was present at all times). The solvent
was evaporated, water was added to the residue and
the yellow solid was filtered and washed with water to
give the intermediate chloroethyl amide (0.54g, 82%),
mp240–243 ꢁC. 1H NMR (CDCl3): d 2.85 (s, CH3),
3.70 (s, CH3), 3.80 (t, J = 5.7Hz, 2H, CH2), 3.96 (q,
J = 5.7Hz, 2H, CH2), 7.51 (t, J = 7.6Hz, 1H), 7.74 (d,
J = 6.8Hz, 1H), 7.88 (d, J = 8.3Hz, 1H), 8.60 (s, 1H),
9.29 (s, 1H), 11.46 (s, 1H, NH).
The following compounds were prepared in a similar
manner.
4.43. N-[2-(Dimethylamino)ethyl]-6-methyl-1-oxo-2-
(2,2,2-trifluoroethyl)-1,2-dihydrobenzo[b][1,6]naphthyr-
idine-4-carboxamide (2f)
A mixture of this amide (0.25g) and 2M methylamine in
tetrahydrofuran (3.5mL) was heated in a sealed tube at
90–100ꢁC for 2.5days. Some solid was present at all
times. Water was added (the solid dissolved) and the
solution was extracted (·3) with dichloromethane. The
combined extracts were washed (·2) with water, dried,
and the solvent evaporated to leave an orange glass
(0.25g). Crystallization from acetonitrile gave the amide
2dd (0.09g), though still slightly impure. Further
purification was achieved by preparing an oxalate salt
in ethanol. Recrystallization from methanol/water/ether
gave a yellow solid, mp230–232 ꢁC (dec). 1H NMR
(DMSO-d6+trace CF3CO2H): d 2.59 (t, J = 4.6Hz, 3H,
+NH2CH3), 2.76 (s, 3H, 6-CH3), 3.18 (br s, 2H, CH2),
3.70 (s, 2H, CH3-2), 3.75 (q, J = 5.7Hz, 2H, CH2),
7.58 (t, J = 8.0Hz, 1H), 7.85 (d, J = 6.7Hz, 1H),
8.12 (d, J = 8.2Hz, 1H), 8.53 (br s, 2H, +NH2CH3),
8.63 (s, 1H, H-3), 9.36 (s, 1H, H-10), 11.10 (s, 1H,
CONH). Anal. Calcd for C18H20N4O2ÆC2H2O4Æ0.25-
H2O: C, 57.3; H, 5.4; N, 13.4. Found: C, 57.3; H, 5.2; N,
13.3%.
From acid 5f, and obtained as a yellow solid (83%), mp
227–230ꢁC (from acetonitrile). 1H NMR (CDCl3):
d 2.30 [s, 6H, N(CH3)2], 2.63 (t, J = 6.4Hz, 2H,
CH2CH2NMe2), 2.85 (s, 3H, ArCH3), 3.72 (q,
J = 6.1Hz, 2H, CH2CH2NMe2), 4.73 (q, J = 8.4Hz,
2H, CH2CF3), 7.51 (t, J = 7.6Hz, 1H, H-8), 7.74
(d, J = 6.9Hz, 1H, H-7), 7.85 (d, J = 8.2Hz, H-1,
H-9), 8.58 (s, 1H, H-3), 9.27 (s, 1H, H-10), 10.84 (br
s, 1H, CONH). 13C NMR (CDCl3): d 18.4 (ArCH3),
37.8 (CH2CH2NMe2), 45.4 [N(CH3)2], 48.3 (q,
J = 35.3Hz, CH2CF3), 58.8 (CH2CH2NMe2), 111.3 (C-
4), 119.1 (C-10a), 123.4 (q, J = 280Hz, CH2CF3),
126.3 (C-9a), 127.2 (CH, C-8), 127.4 (CH, C-9),
133.4 (CH, C-7), 136.3 (C-6), 140.6 (CH, C-10), 142.1
(CH, C-3), 148.6 (C-5a), 148.7 (C-4a), 162.3 (C-1),
164.0 (CONH). Anal. Calcd for C20H21F3N4O2:
C, 59.1; H, 5.2; N, 13.8. Found: C, 59.4; H, 5.4; N,
13.9%.
4.44. N-[2-(Dimethylamino)ethyl]-2-(ethoxycarbonyl-
methyl)-6-methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naph-
thyridine-4-carboxamide (2h)
4.42. N-[2-(Dimethylamino)ethyl]-2-ethyl-6-methyl-1-
oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carboxam-
ide (2d)
From acid 5h, with a reflux time of 48h and a
recharge with an equal amount of CDI after 24h,
and obtained as a yellow solid (79%), mp214–
4.42.1. Method (b) for carboxamide formation. A mixture
of acid 5d (0.23g, 0.81mmol) and 1,10-carbonyldiimid-
azole (CDI) (0.66g, 4.07mmol) in 1,4-dioxane (15mL)
was heated under reflux for 24h, during which time dis-
solution occurred. The solvent was removed at reduced
pressure and to the residue was added, N,N-dimethyle-
thylenediamine (1mL, 9.1mmol) in dichloromethane
(25mL). The solution was then stirred for 16h at room
temperature. More dichloromethane was added and the
solution was washed with 10% sodium hydroxide (·1)
and water (·3). The organic fraction was dried over
magnesium sulfate and the solvent was removed at
reduced pressure to give the amide 2d as a bright yellow
solid (0.26g, 91%), mp157–158 ꢁC (from acetonitrile).
1H NMR (CDCl3): d 1.37 (t, J = 7.2Hz, 3H, CH2CH3),
2.23 [s, 6H, N(CH3)2], 2.54 (t, J = 6.5Hz, 2H,
CH2CH2NMe2), 2.66 (s, 3H, ArCH3), 3.63 (q,
J = 6.2Hz, 2H, CH2CH2NMe2), 4.05 (q, J = 7.2Hz,
2H, CH2CH3), 7.32 (dd, J = 8.0, 7.2Hz, 1H, H-8), 7.55
215ꢁC (from acetonitrile). 1H NMR (CDCl3):
d
1.28 (t, J = 7.2Hz, 3H, CO2CH2CH3), 2.29 [s, 6H,
N(CH3)2], 2.62 (t, J = 6.4Hz, 2H, CH2CH2NMe2),
2.87 (s, 3H, ArCH3), 3.72 (q, J = 5.9Hz, CH2-
CH2NMe2), 4.25 (q, J = 7.1Hz, CO2CH2CH3), 4.78 (s,
2H, CH2CO2Et), 7.51 (t, J = 7.6Hz, 1H, H-8), 7.74 (d,
J = 6.9Hz, 1H, H-7), 7.87 (d, J = 8.2Hz, 1H, H-9),
8.53 (s, 1H, H-3), 9.28 (s, 1H, H-10), 10.96
(br t, J = 4.8Hz, 1H, CONH). 13C NMR (CDCl3):
d
13.7
(CO2CH2CH3),
18.1
(ArCH3),
37.3
(CH2CH2NMe2), 45.1 [N(CH3)2], 50.1 (CH2CO2Et),
58.4 (CH2CH2NMe2), 61.6 (CO2CH2CH3), 109.8 (C-
4), 118.7 (C-10a), 125.5 (C-9a), 126.4 (CH, C-8), 126.9
(CH, C-9), 132.6 (CH, C-7), 135.6 (C-6), 139.6 (CH,
C-10), 142.7 (CH, C-3), 147.8 (C-5a), 148.4 (C-4a),
162.0 (C-1), 163.9 (CONH), 166.9 (CO2Et). Anal. Calcd
for C22H26N4O4: C, 64.4; H, 6.4; N, 13.7. Found: C,
64.5; H, 6.4; N, 13.9%.

1352
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
4.45. N-[2-(Dimethylamino)ethyl]-2-(3,4-dimethoxybenz-
yl)-6-methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyr-
idine-4-carboxamide (2j)
5.30 (s, 2H, CH2Pyr), 7.10 (dd, J = 7.0, 5.2Hz, 1H,
H-50), 7.26–7.33 (m, 2H, H-30, H-8), 7.52–7.59 (m, 2H,
H-40, H-7), 7.64 (d, J = 8.2Hz, 1H, H-9), 8.46 (d,
J = 4.4Hz, 1H, H-60), 8.66 (s, 1H, H-3), 9.02 (s,
1H, H-10), 10.79 (br t, J = 5.1Hz, 1H, CONH).
13C NMR (CDCl3): d 18.3 (ArCH3), 37.3 (CH2-
CH2NMe2), 45.2 [N(CH3)2], 53.7 (CH2Pyr), 58.6
(CH2CH2NMe2), 109.6 (C-4), 119.1 (C-10a), 122.1
(CH, C-30), 122.7 (CH, C-50), 125.5 (C-9a), 126.4 (CH,
C-8), 127.0 (CH, C-9), 132.6 (CH, C-7), 135.6 (C-6),
136.7 (CH, C-40), 139.6 (CH, C-10), 143.4 (CH, C-3),
147.7 (C-5a), 148.5 (C-4a), 149.6 (CH, C-60), 155.0 (C-
20), 162.2 (C-1), 164.3 (CONH). Anal. Calcd for
C24H25N5O2: C, 69.4; H, 6.1; N, 16.9. Found: C, 69.1;
H, 6.2; N, 16.8%.
From acid 5j, with a reflux time of 48h and a recharge
with an equal amount of CDI after 24h, and obtained
as a yellow solid (85%), mp213–214 ꢁC (from acetoni-
1
trile). H NMR (CDCl3): d 2.22 [s, 6H, N(CH3)2], 2.52
(t, J = 6.4Hz, 2H, CH2CH2NMe2), 2.63 (s, 3H, ArCH3),
3.62 (q, J = 6.1Hz, 2H, CH2CH2NMe2), 3.75 (s, 3H,
OCH3), 3.78 (s, 3H, OCH3), 5.09 (s, 2H, CH2 Ph),
6.74 (d, J = 8.5Hz, 1H, H-50), 6.90–6.92 (m, 2H, H-20,
H-60), 7.27 (t, J = 7.6Hz, 1H, H-8), 7.49 (d, J = 6.8Hz,
1H, H-7), 7.61 (d, J = 8.1Hz, 1H, H-9), 8.55 (s, 1H,
H-3), 8.99 (s, 1H, H-10), 10.70 (br t, J = 5.3Hz, 1H,
CONH). 13C NMR (CDCl3): d 18.2 (ArCH3), 37.4
(CH2CH2NMe2), 45.2 [N(CH3)2], 51.9 (CH2Ph), 55.6
(OCH3), 55.7 (OCH3), 58.6 (CH2CH2NMe2), 109.6 (C-
4), 111.1 (CH, C-50), 111.5 (CH, C-60), 119.1 (C-10a),
120.9 (CH, C-20), 125.4 (C-9a), 126.2 (CH, C-8), 126.9
(CH, C-9), 128.2 (C-10), 132.4 (CH, C-7), 135.5 (C-6),
139.5 (CH, C-10), 142.3 (CH, C-3), 147.6 (C-5a), 148.2
(C-4a), 148.9 (C-40), 149.1 (C-30), 162.1 (C-1), 164.1
(CONH). Anal. Calcd for C27H30N4O4: C, 68.3; H,
6.4; N, 11.8. Found: C, 68.5; H, 6.s6; N, 11.8%.
4.48. N-[2-(Dimethylamino)ethyl]-6-methyl-1-oxo-2-[3-
(2-oxopyrrolidin-1-yl)propyl]-1,2-dihydrobenzo[b][1,6]-
naphthyridine-4-carboxamide (2m)
From acid 5m, with a reflux time of 24h, and obtained
as a yellow solid (89%), mp170–171 ꢁC (from acetoni-
1
trile). H NMR (CDCl3): d 1.96–2.06 (m, 4H), 2.25 [s,
6H, N(CH3)2], 2.35 (t, J = 8.1Hz, 2H), 2.58 (t,
J = 6.5Hz, 2H), 2.75 (s, 3H, ArCH3), 3.35–3.42 (m,
4H), 3.66 (q, J = 5.9Hz, 2H), 4.00–4.05 (m, 2H), 7.41
(dd, J = 7.3, 7.9Hz, 1H, H-8), 7.64 (d, J = 6.9Hz, 1H,
H-7), 7.76 (d, J = 8.1Hz, 1H, H-9), 8.52 (s, 1H, H-3),
9.13 (s, 1H, H-10), 10.85 (br t, J = 3.5Hz, 1H, CONH).
13C NMR (CDCl3): d 17.6 (CH2), 18.0 (ArCH3), 26.6
(CH2), 30.5 (CH2), 37.2 (CH2), 39.5 (CH2), 45.0
[N(CH3)2], 46.6 (CH2), 47.1 (CH2), 58.3 (CH2), 109.3
(C-4), 118.8 (C-10a), 125.3 (C-9a), 126.2 (CH, C-8),
126.8 (CH, C-9), 132.4 (CH, C-7), 135.4 (C-6), 139.2
(CH, C-10), 142.2 (CH, C-3), 147.6 (C-5a), 148.1 (C-
4a), 161.8 (C-1), 163.9 (CONH), 174.8 (C-20). Anal.
Calcd for C25H31N5O3: C, 66.8; H, 7.0; N, 15.6. Found:
C, 66.3; H, 7.1; N, 15.7%.
4.46. N-[2-(Dimethylamino)ethyl]-2-[2-(3,4-dimethoxy-
phenyl)ethyl]-6-methyl-1-oxo-1,2-dihydrobenzo[b][1,6]-
naphthyridine-4-carboxamide (2k)
From acid 5k, with a reflux time of 48h and a recharge
with an equal amount of CDI after 24h, and obtained as
a yellow solid (81%), mp113–114 ꢁC (from acetonitrile).
1H NMR (CDCl3): d 2.26 [s, 6H, N(CH3)2], 2.58 (t,
J = 6.5Hz, 2H, CH2CH2NMe2), 2.77 (s, 3H, ArCH3),
2.98–3.04 (m, 2H, CH2CH2Ph), 3.67 (q, J = 6.1Hz,
2H, CH2CH2NMe2), 3.79 (s, 6H, 2 · OCH3), 4.20–4.25
(m, 2H, CH2CH2Ph), 6.72–6.75 (m, 3H, H-20, H-50, H-
60), 7.41 (t, J = 7.6Hz, 1H, H-8), 7.64 (d, J = 6.8Hz,
1H, H-7), 7.77 (d, J = 8.2Hz, 1H, H-9), 8.51 (s, 1H,
H-3), 9.15 (s, 1H, H-10), 10.83 (br t, J = 5.3Hz, 1H,
CONH). 13C NMR (CDCl3): d 18.4 (ArCH3), 34.9
(CH2CH2Ph), 37.5 (CH2CH2NMe2), 45.4 [N(CH3)2],
4.49. N-[2-(Dimethylamino)ethyl]-2-(4-boronophenyl)-6-
methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (2v)
51.2
(CH2CH2Ph),
55.8
(2 · OCH3),
58.7
From acid 5ee, carried out under nitrogen, with a reflux
time of 48h and a recharge with an equal amount of
CDI after 24h. When the amination reaction was com-
plete, the volatiles were removed at reduced pressure
with heat (ꢁ0.3mmHg, 100ꢁC, 20min) and residual
N,N-dimethylethylenediamine was removed by azeotro-
pic distillation with toluene (·3). The residue was then
boiled in toluene and, while hot, decanted from a brown
oil. The toluene was removed at reduced pressure, and
the residue was crystallized from acetonitrile to give
the intermediate N-[2-(dimethylamino)ethyl]-6-methyl-
1-oxo-2-[4-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-
phenyl]1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbox-
amide as a yellow solid (74%), mp139–141 ꢁC. 1H NMR
(CDCl3): d 1.34 (s, 12H, 4 · CH3), 2.31 [s, 6H,
N(CH3)2], 2.64 (t, J = 6.5Hz, 2H, CH2CH2NMe2),
2.81 (s, 3H, ArCH3), 3.72 (q, J = 6.1Hz, 2H,
CH2CH2NMe2), 7.42–7.48 (m, 3H, H-8, H-20, H-6),
7.69 (d, J = 6.9Hz, 1H, H-7), 7.80 (d, J = 8.1Hz, 1H,
H-9), 7.95 (d, J = 8.3Hz, 2H, H-30, H-50), 8.68 (s, 1H,
(CH2CH2NMe2), 109.5 (C-4), 111.4 (CH, Ar), 111.9
(CH, Ar), 119.3 (C-10a), 120.7 (CH, Ar), 125.7 (C-9a),
126.5 (CH, C-8), 127.2 (CH, C-9), 129.8 (C, Ar), 132.7
(CH, C-7), 135.8 (C-6), 139.7 (CH, C-10), 142.7 (CH,
C-3), 147.8 (C, Ar), 148.0 (C-5a), 148.6 (C-4a), 149.0
(C, Ar), 162.2 (C-1), 164.3 (CONH). Anal. Calcd for
C28H32N4O4: C, 68.8; H, 6.6; N, 11.5. Found: C, 68.7;
H, 6.9; N, 11.5%.
4.47. N-[2-(Dimethylamino)ethyl]-6-methyl-2-(pyridin-2-
yl)methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (2l)
From acid 5l, with a reflux time of 48h and a recharge
with an equal amount of CDI after 24h, and obtained
as a bright yellow solid (75%), mp183–184 ꢁC (from ace-
1
tonitrile). H NMR (CDCl3): d 2.25 [s, 6H, N(CH3)2],
2.57 (t, J = 6.4Hz, 2H, CH2CH2NMe2), 2.67 (s, 3H,
ArCH3), 3.66 (q, J = 6.1Hz, CH2, CH2CH2NMe2),

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1353
H-3), 9.23 (s, 1H, H-10), 10.98 (br t, J = 5.4Hz, 1H,
CONH). 13C NMR (CDCl3): d 18.2 (ArCH3), 24.5
(4 · CH3), 37.2 (CH2CH2NMe2), 45.0 [N(CH3)2], 58.3
(CH2CH2NMe2), 83.8 (2 · C), 109.7 (C-4), 119.4 (C-
10a), 125.5 (2 · CH, C-20, C-60), 125.7 (C-9a), 126.4
(CH, C-8), 127.0 (CH, C-9), 132.7 (CH, C-7), 135.6
(2 · CH, C-30, C-50), 140.1 (CH, C-10), 142.0 (C-10),
142.8 (CH, C-3), 147.8 (C-5a), 148.4 (C-4a), 161.7 (C-
1), 164.1 (CONH). C-6 and C-40 were not observed.
NMR (CDCl3): d 2.17 [s, 6H, N(CH3)2], 2.28 [s, 6H,
N(CH3)2], 2.34 (t, J = 6.0Hz, 2H, CH2CH2NMe2),
2.60 (t, J = 6.5Hz, 2H, CH2CH2NMe2), 2.81 (s, 3H,
ArCH3), 3.19 (q, J = 5.8Hz, 2H, CH2CH2NMe2), 3.69
(q, J = 6.2Hz, 2H, CH2CH2NMe2), 4.30–4.32 (m, 2H,
CH2CH2OCO), 4.39–4.43 (m, 2H, CH2CH2OCO), 5.82
(br s, 1H, CONH), 7.47 (t, J = 7.6Hz, 1H, H-8), 7.70
(d, J = 6.8Hz, 1H, H-7), 7.83 (d, J = 8.1Hz, 1H, H-9),
8.58 (s, 1H, H-3), 9.23 (s, 1H, H-10), 10.99 (br s, 1H,
CONH-4). 13C NMR (CDCl3): d 18.2 (ArCH3),
37.3 (CH2CH2NMe2), 38.1 (CH2CH2NMe2), 44.8
[N(CH3)2], 45.1 [N(CH3)2], 48.8 (CH2CH2OCO),
58.0 (CH2CH2NMe2), 58.5 (CH2CH2NMe2), 61.9
(CH2CH2OCO), 109.0 (C-4), 119.0 (C-10a), 125.6 (C-
9a), 126.3 (CH, C-8), 127.0 (CH, C-9), 132.6 (CH, C-
7), 135.5 (C-6), 139.7 (CH, C-10), 143.4 (CH, C-3),
147.9 (C-5a), 148.4 (C-4a), 155.6 (CONH), 162.1 (C-1),
164.4 (CONH). HRMS (EI) calcd for C25H34N6O4
[M+]: 482.2643. Found: 482.2626.
Water (5mL) was added to a solution of this compound
(0.12g, 0.23mmol) in methanol (5mL), and the whole
was heated at reflux for 30min. The volume was then re-
duced to ca. 2mL at reduced pressure, water was added,
and the solid was filtered, washed with water, and
recrystallized from ethanol to give the boronic acid 2v
as a yellow solid (0.05g, 49%), mp242–244 ꢁC. 1H
NMR (DMSO-d6): d 2.23 [s, 6H, N(CH3)2], 2.56 (t,
J = 5.8Hz, 2H, CH2CH2NMe2), 2.82 (s, 3H, ArCH3),
3.59 (q, J = 5.7Hz, 2H, CH2CH2NMe2), 7.52 (d,
J = 8.0Hz, 2H, H-30, H-50), 7.59 (t, J = 7.5Hz, 1H, H-
8), 7.86 (d, J = 6.7Hz, 1H, H-7), 7.95 (d, J = 8.0Hz,
2H, H-20, H-60), 8.14 (d, J = 8.0Hz, 1H, H-9), 8.23 [s,
2H, B(OH)2], 8.43 (s, 1H, H-3), 9.39 (s, 1H, H-10),
10.76 (br t, J = 4.8Hz, 1H, CONH). 13C NMR
(DMSO-d6): d 17.8 (ArCH3), 37.1 (CH2CH2NMe2),
45.1 [N(CH3)2], 58.5 (CH2CH2NMe2), 109.2 (C-4),
119.5 (C-10a), 125.7 (C-9a), 125.8 (C-20, C-60), 126.8
(CH, C-8), 127.6 (CH, C-9), 133.2 (CH, C-7), 135.1
(C-30, C-50), 135.3 (C-6), 140.1 (CH, C-10), 141.8 (C-
10), 143.2 (CH, C-3), 147.4 (C-5a), 148.4 (C-4a), 161.3
(C-1), 163.2 (CONH). C-40 was not observed. Anal.
Calcd for C24H25BN4O4Æ0.25H2O: C, 64.2; H, 5.7; N,
12.3. Found: C, 64.4; H, 5.9; N, 12.5%.
4.52. N-[2-(Dimethylamino)ethyl]-2-[N-(((2-(dimethyl-
amino)ethyl)amino)carbonyl)-1H-indol-3-yl]ethyl-6-
methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (8b)
From acid 5n, with a reflux time of 48h and a recharge
with an equal amount of CDI after 24h, and obtained
as a yellow solid (62%), mp182–185 ꢁC (from acetoni-
1
trile). H NMR (CDCl3): d 2.27 [s, 12H, 2 · N(CH3)2],
2.52–2.61 (m, 4H, 2 · CH2CH2NMe2), 2.77 (s, 3H,
ArCH3), 3.18 (t, J = 7.7Hz, 2H, CH2CH2Indole), 3.50
(q, J = 5.4Hz, 2H, CH2CH2NMe2-10), 3.68 (q,
J = 6.0Hz, 2H, CH2CH2NMe2-4), 4.32 (t, J = 7.7Hz,
2H, CH2CH2Indole), 6.60 (br t, J = 4.1Hz, 1H,
CONH-10), 7.18 (t, J = 7.4Hz, 1H, H-50), 7.27 (t,
J = 7.8Hz, 1H, H-60), 7.39–7.44 (m, 2H, H-20, H-8),
7.64–7.66 (m, 2H, H-40, H-7), 7.77 (d, J = 8.2Hz, 1H,
H-9), 8.09 (d, J = 8.2Hz, 1H, H-70), 8.55 (s, 1H, H-
3), 9.17 (s, 1H, H-10), 10.87 (br t, J = 5.2Hz, 1H,
CONH-4). 13C NMR (CDCl3): d 18.4 (ArCH3),
24.8 (CH2CH2Indole), 37.6 (CH2CH2NMe2-4), 37.9
(CH2CH2NMe2-10), 45.0 [N(CH3)2], 45.4 [N(CH3)2],
49.7 (CH2CH2Indole), 57.7 (CH2CH2NMe2-10), 58.7
(CH2CH2NMe2-4), 109.5 (C-4), 114.4 (CH, C-70),
115.8 (CONH-10), 118.8 (CH, C-40), 119.3 (C-10a),
121.98 (CH, C-20), 122.03 (CH, C-50), 124.4 (CH, C-
60), 125.8 (C-9a), 126.5 (CH, C-8), 127.2 (CH, C-9),
129.5 (C, C-3a0), 132.8 (CH, C-7), 135.6 (C-7a0),
135.8 (C-6), 139.7 (CH, C-10), 142.7 (CH, C-3), 148.0
(C-5a), 148.5 (C-4a), 152.0 (C-30), 162.2 (C-1), 164.4
(CONH-4). Anal. Calcd for C33H39N7O3Æ0.5H2O: C,
67.1; H, 6.8; N, 16.6. Found: C, 67.2; H, 6.7; N,
16.6%.
4.50. N-[2-(Dimethylamino)ethyl]-7-methoxy-2-methyl-
1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbox-
amide (2w)
From acid 5w, with a reflux time of 96h and a recharge
with an equal amount of CDI after 48h, and obtained as
a yellow solid (80%), mp213–215 ꢁC (from acetonitrile).
1H NMR (CDCl3): d 2.50 [s, 6H, N(CH3)2], 2.78 (t,
J = 6.0Hz, 2H, CH2CH2NMe2), 3.67 (s, 3H, NCH3),
3.77 (q, J = 5.8Hz, 2H, CH2CH2NMe2), 4.02 (s, 3H, Ar-
OCH3), 7.22 (dd, J = 9.1, 2.2Hz, 1H, H-8), 7.43 (d,
J = 2.2Hz, 1H, H-6), 7.85 (d, J = 9.1Hz, 1H, H-9),
8.53 (s, 1H, H-3), 9.14 (s, 1H, H-10), 11.36 (br s, 1H,
CONH). 13C NMR (CDCl3): d 36.8 (CH2CH2NMe2,
NCH3), 45.0 [N(CH3)2], 55.6 (ArOCH3), 57.7
(CH2CH2NMe2), 105.3 (CH, C-6), 108.8 (C-4), 117.3
(C-10a), 120.9 (CH, C-8), 121.4 (C-9a), 130.0 (CH, C-
9), 138.3 (CH, C-10), 143.1 (CH, C-3), 149.7 (C-4a),
150.9 (C-5a), 162.5 (C-1), 163.4 (C-7), 164.4 (CONH).
Anal. Calcd for C19H22N4O3: C, 64.4; H, 6.3; N, 15.8.
Found: C, 64.4; H, 6.5; N, 15.6%.
4.53. N-[2-(Dimethylamino)ethyl]-2-hydroxyethyl-6-
methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-
carboxamide (2g)
4.51. N-[2-(Dimethylamino)ethyl]-2-[((2-(dimethylami-
no)ethyl)amino)carbonyloxy]ethyl-6-methyl-1-oxo-1,2-
dihydrobenzo[b][1,6]naphthyridine-4-carboxamide (8a)
To the carbamate 8a (0.55g, 1.49mmol) in ethanol
(25mL) was added 10% sodium hydroxide (20mL),
and the whole was heated under reflux for 1h, then
cooled on ice, adjusted to pH ꢁ 8 with concentrated
hydrochloric acid, and evaporated to dryness at reduced
From acid 5g, with a reflux time of 48h, and obtained as
a yellow solid (63%), mp75–76 ꢁC (from toluene ·3). 1H

1354
L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
pressure. The residual solid was boiled in acetonitrile,
the mixture was filtered while hot, and the filtrate was
taken to dryness at reduced pressure to give an orange
solid (0.26g). This solid was dissolved in a little warm
ethanol and added to a bed of silica. This was eluted
with a little ethanol, then with ethanol/triethylamine
(25:1). The ethanol/triethylamine eluate was taken to
dryness at reduced pressure. The residual solid (0.17g)
was dissolved in a little chloroform, filtered through a
bed of basic alumina, washed with chloroform, and then
eluted with methanol. The methanol eluate was evapo-
rated to dryness under reduced pressure to give a yellow
solid (0.12g), which was recrystallized twice from
dichloromethane to give the amide 2g as a yellow solid
(0.10g, 24%), mp174–180 ꢁC. 1H NMR (CDCl3): d
2.27 [s, 6H, N(CH3)2], 2.43 (s, 3H, ArCH3), 2.54 (t,
J = 6.4Hz, 2H, CH2CH2NMe2), 3.55 (q, J = 6.0Hz,
2H, CH2CH2NMe2), 4.03–4.06 (m, 2H, CH2CH2OH),
4.20–4.23 (m, 2H, CH2CH2OH), 7.34 (t, J = 7.5Hz,
1H, H-8), 7.50 (d, J = 6.7Hz, 1H, H-7), 7.63 (d,
J = 8.1Hz, 1H, H-9), 8.56 (s, 1H, H-3), 8.96 (s, 1H, H-
10), 10.67 (br t, J = 5.0Hz, 1H, CONH). 13C NMR
(CDCl3): d 17.9 (ArCH3), 37.0 (CH2CH2NMe2), 45.0
[N(CH3)2], 52.3 (CH2CH2OH), 58.1 (CH2CH2NMe2),
60.2 (CH2CH2OH), 108.2 (C-4), 118.7 (C-10a), 125.1
(C-9a), 126.1 (CH, C-8), 126.8 (CH, C-9), 132.3 (CH,
C-7), 135.3 (C-6), 139.0 (CH, C-10), 143.9 (CH, C-3),
147.3 (C-5a), 147.9 (C-4a), 162.4 (C-1), 164.3 (CONH).
HRMS (LSI) calcd for C20H25N4O3 [(M+H)+]:
369.1928. Found: 369.1940.
4.55. In vitro cytotoxicity assays
Murine P388 leukemia cells, Lewis lung carcinoma cells
(LLTC), and human Jurkat leukemia cells (JLC), to-
gether with their amsacrine and doxorubicin-resistant
derivatives (JLA and JLD, respectively), were obtained
and cultured as described.13 Growth inhibition assays
were performed by culturing cells at 4.5 · 103 (P388),
and 103 (LLTC) per well in microculture plates
(150mL per well) for 3 (P388) or 4days in the presence
of drug. Cell growth was determined by [3H]TdR up-
take (P388)14 or the sulforhodamine assay.15 Indepen-
dent assays were performed at least in duplicate.
4.56. In vivo tumor assays
Colon 38 tumors were grown subcutaneously from
1mm3 fragments implanted in one flank of BDF1 mice
(anesthetized with pentobarbitone 90mg/kg). When
tumors reached a diameter of approximately 4–6mm
(7–8days), mice were divided into control and drug
treatment groups (five mice/group), with similar average
tumor volumes in each group. Drugs were administered
as solutions of the hydrochloride salts in distilled water,
injected intraperitoneally in a volume of 0.01mL/g body
weight, using either single dose or intermittent (q4d · 3)
schedules. The mice were monitored closely and tumor
diameters were measured with callipers three times a
week. Tumor volumes were calculated as 0.52 · a2 · b,
where a and b are the minor and major tumor axes
and data plotted on a semi-logarithmic graph as mean
tumor volumes ( SEM) versus time after treatment.
The growth delay was calculated as the time taken for
tumors to reach a mean volume 4-fold higher than their
pre-treatment volume.
4.54. N-[2-(Dimethylamino)ethyl]-2-[2-(1H-indol-3-
yl)ethyl]-6-methyl-1-oxo-1,2-dihydrobenzo[b][1,6]naph-
thyridine-4-carboxamide (2n)
To a hot solution of the bisamide 8b (0.58g, 1.00mmol)
in ethanol (10mL) was added 10% sodium hydroxide
(10mL), and the whole was heated at reflux for
40min. The reaction mixture was then evaporated to
dryness under reduced pressure, water was added, and
the solid was filtered and washed with water to give
2n as a gold solid (0.42g, 90%), mp105–107 ꢁC
Acknowledgements
M.L.R is grateful for the award of an APRA.
1
References and notes
(from acetonitrile). H NMR (CDCl3): d 2.31 [s, 6H,
N(CH3)2], 2.64 (t, J = 6.4Hz, 2H, CH2CH2NMe2), 2.82
(s, 3H, ArCH3), 3.21 (t, J = 7.7Hz, 2H, CH2CH2In-
dole), 3.73 (q, J = 6.1Hz, 2H, CH2CH2NMe2), 4.30 (t,
J = 7.8Hz, 2H, CH2CH2Indole), 6.99 (d, J = 2.0Hz,
1H, H-20), 7.06–7.14 (m, 2H, H-50, H-6), 7.30 (d,
J = 7.7Hz, 1H, H-70), 7.46 (t, J = 7.6Hz, 1H, H-8),
7.66–7.70 (m, 2H, H-40, H-7), 7.82 (d, J = 8.2Hz, 1H,
H-9), 8.51 (s, 1H, H-3), 8.62 (br s, 1H, NH-10), 9.24
(s, 1H, H-10), 10.98 (br t, J = 5.3Hz, 1H, CONH).
13C NMR (CDCl3): d 18.2 (ArCH3), 24.8 (CH2CH2In-
dole), 37.2 (CH2CH2NMe2), 45.0 [N(CH3)2], 50.2
(CH2CH2Indole), 58.4 (CH2CH2NMe2), 109.0 (C),
110.9 (CH, C-70), 111.1 (C), 118.2 (CH, C-40), 119.2
(CH, C-50), 121.7 (CH, C-60), 122.0 (CH, C-2), 125.6
(C-9a), 126.2 (CH, C-8), 126.8 (C-3a0), 127.0 (CH, C-
9), 132.5 (CH, C-7), 135.5 (C-6), 136.0 (C-7a0), 139.5
(CH, C-3), 142.7 (CH, C-10), 147.8 (C-5a), 148.4 (C-
4a), 162.1 (C-1), 164.4 (CONH). C-30 was not observed.
HRMS (EI) calcd for C28H29N5O2 [M+]: 467.2323.
Found: 467.2314.
1. Atwell, G. J.; Rewcastle, G. W.; Baguley, B. C.; Denny,
W. A. J. Med. Chem. 1987, 30, 664.
2. Baguley, B. C.; Zhuang, L.; Marshall, E. M. Cancer
Chemother. Pharmacol. 1995, 36, 244.
3. Deady, L. W.; Rodemann, T.; Zhuang, L.; Baguley, B. C.;
Denny, W. A. J. Med. Chem. 2003, 46, 1049.
4. Ames, D. E.; Dodds, W. D. J. Chem. Soc., Perkin Trans. 1
1972, 705.
5. Kubo, K.; Ukawa, K.; Kuzuna, S.; Nohara, A. Chem.
Pharm. Bull. 1986, 34, 1108.
6. Deady, L. W.; Rodemann, T. J. Heterocycl. Chem. 2001,
38, 1185.
7. Note that letter codes for acids 5 are the same as for
carboxamides 2 of Table 1.
8. Barker, A. J.; Gibson, K. H.; Grundy, W.; Godfrey, A. A.;
Barlow, J. J.; Healy, M. P.; Woodburn, J. R.; Ashton, S.
E.; Curry, B. J.; Scarlett, L.; Henthorn, L.; Richards, L.
Bioorg. Med. Chem. Lett. 2001, 11, 1911.
9. Vicker, N.; Burgess, L.; Chuckowree, I. S.; Dodd, R.;
Folkes, A. J.; Hardick, D. J.; Hancox, T. C.; Miller, W.;
Milton, J.; Sohal, S.; Wang, S.; Wren, S. P.; Charlton, P.

L. W. Deady et al. / Bioorg. Med. Chem. 13 (2005) 1341–1355
1355
A.; Dangerfield, W.; Liddle, C.; Mistry, P.; Stewart, A. J.;
Denny, W. A. J. Med. Chem. 2002, 45, 721.
10. Spicer, J. A.; Gamage, S. A.; Atwell, G. J.; Finlay, G. J.;
Baguley, B. C.; Denny, W. A. J. Med. Chem. 1997, 40,
1919.
13. Finlay, G. J.; Riou, J.-F.; Baguley, B. C. Eur. J. Cancer
1996, 32A, 708.
14. Marshall, E. S.; Finlay, G. J.; Matthews, J. H. L.; Shaw, J.
H. F.; Nixon, J.; Baguley, B. C. J. Natl. Cancer Inst. 1992,
84, 340.
11. In vitro results for colon 38 were not possible as this line
grows only in mice and not in culture.
12. Goldin, A.; Venditti, J. M. NCI Cancer Treat. Rev. 1980,
7, 167.
15. Skehan, P.; Storeng, R.; Scudiero, D.; Monks, A.;
McMahon, J.; Vistica, D.; Warren, J. T.; Bokesch, H.;
Kenney, S.; Boyd, M. R. J. Natl. Cancer Inst. 1990, 82,
1107.