Synthesis and anti-tumor activities of a novel series of tricyclic 1-anilino-5H-pyridazino[4,5-b]indoles

Article abstract of DOI:10.1002/ardp.200700078

A novel series of 1-anilino-5H-pyridazino[4,5-b]indoles was designed and synthesized in order to find novel potent anti-tumor compounds. Their structures were confirmed by MS, ¹H-NMR, and elemental analysis. All compounds were screened for their cytotoxic activity against two human cancer cell lines (Bel-7420, HT-1080). The compounds 8, 9, and 17 showed 50% growth inhibitory activity in low micromolar concentration (IC₅₀ = 7.7～12.8 μM). Among them, compound 17 displayed the most potent anti-tumor activity with IC₅₀ values of 8.2 μM and 7.9 μM against Bel-7402 and HT-1080, respectively.

Full text of DOI:10.1002/ardp.200700078

424
Arch. Pharm. Chem. Life Sci. 2007, 340, 424–428
Full Paper
Synthesis and Anti-Tumor Activities of a Novel Series of
Tricyclic 1-Anilino-5H-pyridazino[4,5-b]indoles
Rong Dong Li1, 2, Xin Zhai1, Yan Fang Zhao1, Shuang Yu1, and Ping Gong1
1 School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, P.R. China
2 School of Pharmacy, Hunan University of Traditional Chinese Medicine, Changsha, P.R. China
A novel series of 1-anilino-5H-pyridazino[4,5-b]indoles was designed and synthesized in order to
1
find novel potent anti-tumor compounds. Their structures were confirmed by MS, H-NMR, and
elemental analysis. All compounds were screened for their cytotoxic activity against two human
cancer cell lines (Bel-7420, HT-1080). The compounds 8, 9, and 17 showed 50% growth inhibitory
activity in low micromolar concentration (IC50 = 7.7l12.8 lM). Among them, compound 17 dis-
played the most potent anti-tumor activity with IC50 values of 8.2 lM and 7.9 lM against Bel-
7402 and HT-1080, respectively.
Keywords: Anilino-5H-pyridazino[4,5-b]indoles / Anti-tumor activities / Synthesis /
Received: April 12, 2007; accepted: May 30, 2007
DOI 10.1002/ardp.200700078
Structure-activity relationship for 4-anilinoquinazo-
Introduction
line derivatives demonstrated that cationic side chains
in 7-position of quinazoline would produce an increase
in potency of inhibition of EGFR (epidermal growth fac-
tor receptor) and a remarkable improvement in aqueous
solubility [7]. Recently, it has been reported that tricyclic
4-anilinopyrimido[4,5-b]indoles (Fig. 1), which was devel-
oped from 4-anilinoquinazolines, have potential for can-
cer chemotherapy [8]. In view of these observations, we
designed a novel series of 1-anilino-5H-pyridazino[4,5-
b]indoles. Different substituted aminopropoxy moieties
were introduced into the 8-position, and various anilines
were introduced into the 1-position to investigate their
influence on anti-tumor activity.
Cancer is an important health problem that claims the
lives of more than seven million people worldwide every
year. Though a variety of approaches have been taken to
cancer chemotherapy, and many anti-cancer drugs have
been developed for clinical use, cancer still remains one
of the leading causes of human mortality. It is urgently
needed to develop more effective and reliable anti-cancer
agents which can specifically block some targets in
tumor cells. In recent years, a large number of heterocy-
clic compounds with targeted strategies were reported as
potential anti-cancer drugs, which included 4-anilinoqui-
nazolines, 4-anilino-3-quinolinecarbonitriles, pyrrolopyr-
imidines, 4-anilinopyrido[d]pyrimidines, imidazo[4,5-
g]quinazolines, pyrazoloquinazolines, and pyrroloquina-
zolines, etc [1–5]. Among them, the 4-anilinoquinazo-
lines targeting the epidermal growth factor receptor
have shown great progress. Two of them, Iressam (gefiti-
nib) and Tarcevam (erlotinib) were approved by the FDA
for use in patients with non-small cell lung cancer [6].
In this paper, we would like to report the synthesis and
anti-tumor activities of a novel series of tricyclic 1-ani-
lino-5H-pyridazino[4,5-b]indole derivatives represented
by the general formula of 8–19 in Fig. 1.
Results and discussion
The synthetic route of the target compounds is shown in
Scheme 1. The starting material ethyl 5-acetoxy-6-bromo-
2-bromomethyl-1-cyclopropylindole-3-carboxylate 1 was
prepared according to previously reported method [9].
Reaction of 1 with pyridine in trichloromethane afforded
Correspondence: Ping Gong, School of Pharmaceutical Engineering,
Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe Dis-
trict, 110016 Shenyang, P. R. China.
E-mail: gongpinggp@126.com
Fax: +86 24 2388-2925
i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Arch. Pharm. Chem. Life Sci. 2007, 340, 424–428
Novel 1-Anilino-5H-pyridazino[4,5-b]indoles
425
Table 1. The substituents and anti-tumor effect of compounds
8–19.
Compound
IC50 (lM)
R1
NR2R3
Bel-7402 HT-1080
8
9
10
11
12
13
14
15
16
17
18
19
3-chloro-4-fluoro dimethylamino
3-chloro-4-fluoro pyrrolidinyl
3-chloro-4-fluoro morpholinyl
3-chloro-4-fluoro piperidinyl
4-trifluoromethyl dimethylamino
4-trifluoromethyl pyrrolidinyl
4-trifluoromethyl morpholinyl
4-trifluoromethyl piperidinyl
9.4
7.7
12.8
12.3
84.2
12.1
19.6
12.6
157.2
13.6
37.7
17.4
–
304.5
18.0
8.2
–
318.2
9.0
7.9
18.8
11.9
53.7
3,4-difluoro
3,4-difluoro
3,4-difluoro
3,4-difluoro
dimethylamino
pyrrolidinyl
morpholinyl
piperidinyl
35.8
14.7
63.8
Figure 1. Structures of gefitinib, 4-anilinopyrimido[4.5-b]indoles,
and compounds 8–19.
Gefitinib
with the appropriatly substituted anilines in isopropanol
[2], and then reaction of 7a–7c with the appropriate sec-
ondary amines in dimethylformamide afforded the cor-
responding target compounds 8–19 as oxalate.
Table 1 compares the anti-tumor activities of com-
pounds 8–19 against cancer cell lines Bel-7402 and HT-
1080, as determined by MTT (MTT: 3-(4,5-Dimethylthia-
zol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay. Of all
the tested compounds, compound 17 possessed the most
potent anti-tumor activity, with IC50 values of 8.2 lM and
7.9 lM against Bel-7402 and HT-1080 cancer cell lines,
respectively. The data in Table 1 indicate that substitu-
ents on the aniline ring have substantial influence on
anti-tumor activity. The 4-trifluoromethylanilino deriv-
atives 12–15 were less effective than the corresponding
3,4-difluoro and 3-chloro-4-fluoro analogues. For exam-
ple, compound 14 with 4-trifluoromethyl substituent
showed no activity at all, while compound 18 with 3,4-
Reagents and conditions: (a) Py, CHCl3, reflux, 5 h; (b) EtOH, p-Me2NC6H4NO, aq
NaOH, r.t., 24 h; (c) H2O, H2SO4; (d) K2CO3, DMF, BrCH2CH2CH2Cl, 708C, 4 h; (e)
NH2NH2.H2O, HAc, 708C, 2 h; (f) POCl3, DMF, reflux, 2 h; (g) R1PhNH2, i-PrOH, HCl
(trace), reflux, 5 h; (h) K2CO3, DMF, R2R3NH, 608C, 7 h; (i) acetone, oxalic acid, r.t.
difluoro substituent displayed moderate activity (IC50
=
35.8 lM, 18.8 lM, respectively). Introduction of the ami-
nopropoxy moieties at C-8 position of the 1-anilino-5H-
pyridazino[4,5-b]indole showed that the secondary
amines at 3-position of propoxy produced notable effects.
The morpholinylpropoxy led to loss of potency (10 vs 9,
14 vs 13, and 18 vs 17), while 1-pyrrolidinylpropoxy
showed significant improvement in activity (9, 13, and
17).
Scheme 1. Synthetic route of compounds 8–19.
pyridinium salt 2. Compound 2 reacted with freshly pre-
pared p-nitrosodimethylaniline hydrochloride in etha-
nol to yield the nitrone compound, which was hydro-
lyzed to give the desired key intermediate 3 [10]. The con-
densation of 3 with 1,3-bromochloropropane led to com-
pound 4, followed by cyclization with 80% hydrazine
hydrate to give a good yield of 5H-pyridazino[4,5-b]indol-
1-one 5. Treatment of compound 5 with phosphorus oxy-
chloride at reflux produced 1-chloro-5H-pyridazino[4,5-
b]indole 6. Compound 6 was converted to 1-anilino-5H-
pyridazino[4,5-b]indole derivatives 7a–7c by coupling
Experimental
Chemistry
Melting points were determined with capillary tube method,
and the thermometer was uncorrected. Mass spectra were
obtained with a Finnigan LCQ HPLC-MS instrument (Thermo
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www.archpharm.com

426
R. D. Li et al.
Arch. Pharm. Chem. Life Sci. 2007, 340, 424–428
Electron Corporation, Bremen, Germany). 1H-NMR spectra were
run on a Bruker ARX-300 instrument (Bruker Bioscience, Biller-
ica, MA, USA), TMS as the internal stantard. Elemental analysis
was performed by a Carlo-Erba 1106 Elemental analysis instru-
ment (Carlo Erba, Milan, Italy).
7-Bromo-1-chloro-8-(3-chloropropoxy)-5-cyclopropyl-
5H-pyridazino[4,5-b]indole 6
A solution of 5 (31.7 g, 0.08 mol) in phosphorus oxychloride
(100 mL) containing N,N-dimethylformamide (10 drops) was
stirred and heated to reflux for 2 h. The solution was evaporated
and the residue was triturated with water, and saturated aque-
ous sodium hydrogen carbonate was added. The precipitate was
filtered, dried, and then recrystallized from methanol to give 6
(26.9 g, 81.0%) as light yellow crystals. Mp. 197–1998C; MS [MH+]
(m/z): 414.1 (Br = 79), 416.2 (Br = 81); 1H-NMR (DMSO-d6) d: 9.42 (s,
1H), 8.09 (s, 1H), 8.07 (s, 1H), 4.26 (t, 2H), 3.84 (t, 2H), 3.50 (m, 1H),
2.27 (m, 2H), 1.33 (m, 2H), 1.10 (m, 2H).
5-Acetoxy-6-bromo1-cyclopropyl-3-ethoxycarbonyl-
1H-indole-2-methylpyridinium bromide 2
A mixture of ethyl 5-acetoxy-6-bromo-2-bromomethyl-1-cyclo-
propyl-1H-indole-3-carboxylate (91.8 g, 0.2 mol) and pyridine
(23.8 g, 0.30 mol) in trichloromethane (500 mL) was heated
under reflux for 5 h. The reaction mixture was cooled, the
formed crystalline product was filtered and washed with tri-
chloromethane to give 2 (101.0 g, 93.9%) as white powder. Mp.
234–2368C (dec.); MS [MH+] (m/z): 457.3 (Br = 79), 459.3 (Br = 81).
General procedure for the synthesis of 7-bromo-8-
(3-chloropropoxy)-5-cyclopropyl-1-substituted-5H-
pyridazino[4,5-b]indoles 7a–c
To a mixture of 6 (24.9 g, 0.06 mol) and R1PhNH2 (0.072 mol) in
isopropanol (250 mL) was added saturated ethanol hydrochlor-
ide (0.5 mL). After heating to reflux for 5 h, the mixture was
cooled, sufficient triethylamine was added to basify the mixture,
and then filtered to give 7 as light yellow solid (85–90%).
Ethyl 6-bromo-1-cyclopropyl-2-formyl-5-hydroxy-
1H-indole-3-carboxylate 3
To a suspension of 2 (80.7 g, 0.15 mol) and p-nitrosodimethylani-
line hydrochloride (278.8 g, 0.15 mol) in ethanol (400 mL), a sol-
ution of sodium hydroxide (12 g, 0.30 mol) in water (60 mL) was
added dropwise with stirring at room temperature. Then, the
resulting mixture was stirred at room temperature for 24 h. The
precipitated product was collected by filtration and washed
with water. Concentrated sulfuric acid (44.1 g, 0.45 mol) was
added dropwise to a stirred suspension of the resulting wet solid
and water (100 mL). Crushed ice was added after 20 min, and the
crude solid was filtered, washed successively with dilute sodium
bicarbonate solution and water, and then dried to yield 3
7a:
R1 = 3-chloro-4-fluoro: MS [MH+] (m/z): 523.3 (Br = 79), 525.3 (Br =
81); 1H-NMR (DMSO-d6) d: 9.34 (s, 1H), 8.06 (s, 1H), 8.04 (s, 1H), 7.99
(dd, 1H), 7.65 (brs, 1H), 7.43 (t, 1H), 4.25 (t, 2H), 3.83 (t, 2H), 3.50
(m, 1H), 2.25 (m, 2H), 1.34 (m, 2H), 1.10 (m, 2H).
7b:
R1 = 4-trifluoromethyl: MS [MH+] (m/z): 539.4 (Br = 79), 541.4 (Br =
81); 1H-NMR (DMSO-d6) d: 9.38 (s, 1H), 8.05 (s, 1H), 7.84–7.81 (d,
3H), 7.67 (d, 2H), 4.20 (t, 2H), 3.81 (t, 2H), 3.50 (m, 1H), 2.22 (m,
2H), 1.30 (m, 2H), 1.08 (m, 2H).
1
(42.6 g, 80.7%) as yellow solid. Mp. 240–2428C; H-NMR (DMSO-
d6) d: 10.75 (s, 1H), 7.45 (s, 1H), 7.06 (s, 1H), 4.43 (q, 2H), 3.25 (m,
1H), 1.36 (t, 3H), 1.25 (m, 2H), 1.08 (m, 2H).
7c:
R1 = 3,4-difluoro: MS [MH+] (m/z): 507.2 (Br = 79), 509.2 (Br = 81);
1H-NMR (DMSO-d6) d: 9.36 (s, 1H), 8.07 (s, 1H), 8.05 (s, 1H), 7.86-
7.76 (m, 1H), 7.48–7.41 (m, 2H), 4.25 (t, 2H), 3.82 (t, 2H), 3.50 (m,
1H), 2.24 (m, 2H), 1.33 (m, 2H), 1.10 (m, 2H).
Ethyl 6-bromo-5-(3-chloropropoxy)-1-cyclopropyl-
2-formyl-1H-indole-3-carboxylate 4
A mixture of 3 (42.3 g, 0.12 mol), potassium carbonate (24.8 g,
0.18 mol) and 1,3-bromochloropropane (28.4 g, 0.18 mol) in N,N-
dimethylformamide (150 mL) was stirred and heated at 708C for
4 h. The mixture was cooled and then poured into water, the
resulting precipitate was collected and dried to give 4 (46.0 g,
89.5%) as light brown solid. Mp. 137-1398C; 1H-NMR (DMSO-d6) d:
10.77 (s, 1H), 7.47 (s, 1H), 7.42 (s, 1H), 4.44 (q, 2H), 4.26 (t, 2H),
3.83 (t, 2H), 3.25 (m, 1H), 2.25 (m, 2H), 1.37 (t, 3H), 1.28 (m, 2H),
1.08 (m, 2H).
General procedure for the synthesis of compounds 8–19
A mixture of 7 (0.05 mol), potassium carbonate (13.8 g, 0.10 mol)
and R2R3NH (0.06 mol) in N,N-dimethylformamide (100 mL) was
stirred and heated at 608C for 7 h. It was cooled to room temper-
ature, and then poured into water. The resulting precipitate was
collected, dried, and then dissolved in acetone. The solution of
oxalic acid (0.06 mol) in acetone (20 mL) was added, the formed
solid was filtered and dried to give 8–19 as light yellow solid
(80–87%).
7-Bromo-8-(3-chloropropoxy)-5-cyclopropyl-1,2-dihydro-
5H-pyridazino[4,5-b]indol-1-one 5
7-Bromo-1-(3-chloro-4-fluorophenylamino)-5-
cyclopropyl-8-[3-(dimethylamino)propoxy]-5H-
pyridazino[4,5-b]indole oxalate 8
A suspension of 4 (42.9 g, 0.10 mol) and 80% hydrazine hydrate
(7.5 g, 0.12 mol) in glacial acetic acid (100 mL) was stirred and
heated at 708C for 2 h, after cooling to room temperature, the
formed precipitate was filtered, washed with ethanol and dried
to give 5 (33.8 g, 85.2%) as white powder. mp 221–2238C; MS [M+]
(m/z): 418.2 (Br = 79), 420.2 (Br = 81); 1H-NMR (DMSO-d6) d: 10.53
(s, 1H), 9.41 (s, 1H), 8.07 (s, 1H), 8.05 (s, 1H), 4.25 (t, 2H), 3.82 (t,
2H), 3.48 (m, 1H), 2.26 (m, 2H), 1.32 (m, 2H), 1.10 (m, 2H).
Yield: 81%; mp. 153–1558C; MS [MH+] (m/z): 532.2 (Br = 79), 534.2
(Br = 81); 1H-NMR (DMSO-d6) d: 9.32 (s, 1H, C4-H), 8.05 (s, 1H, C6-H),
8.03 (s, 1H, C9-H), 7.97 (dd, 1H, J = 6.6, 2.5 Hz, ph-H), 7.64 (brs, 1H,
ph-H), 7.40 (t, 1H, J = 9.0 Hz ph-H), 4.25 (t, 2H, J = 5.7 Hz,
CH2CH2CH2O), 3.50 (m, 1H, NCH), 3.31 (t, 2H, J = 7.0 Hz,
NCH2CH2CH2), 2.85 (s, 6H, N(CH3)2), 2.23 (brs, 2H, CH2CH2CH2),
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Arch. Pharm. Chem. Life Sci. 2007, 340, 424–428
Novel 1-Anilino-5H-pyridazino[4,5-b]indoles
427
1.35 (m, 2H, CH2CH2), 1.09 (m, 2H, CH2CH2); Anal. Calcd. for
C24H24BrClFN5O N C2H2O4: C 50.14, H 4.21, N 11.24; Found: C
50.02, H 4.31, N 11.41.
7-Bromo-1-(4-trifluoromethylphenylamino)-5-cyclopropyl-
8-[3-(pyrrolidin-1-yl)propoxy]-5H-pyridazino[4,5-b]indole
oxalate 13
Yield: 85%; mp. 120–1228C; MS [MH+] (m/z): 574.1 (Br = 79), 576.2
(Br = 81); 1H-NMR (DMSO-d6) d: 9.41 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
7.81–7.78 (d, 3H, C9-H, ph-2H), 7.67 (d, 2H, J = 8.4 Hz, ph-2H), 4.15
(t, 2H, J = 5.6 Hz, CH2CH2CH2O), 3.51 (m, 1H, NCH), 3.35 (brs, 6H,
pyrrolidinyl-2,5-2H, NCH2CH2CH2), 2.21 (brs, 2H, CH2CH2CH2),
1.96 (brs, 4H, pyrrolidinyl-2,5-2H), 1.36 (m, 2H, CH2CH2), 1.11 (m,
2H, CH2CH2); Anal. Calcd. for C27H27BrF3N5O N C2H2O4: C 52.42, H
4.40, N 10.54; Found: C 52.52, H 4.55, N 10.36.
7-Bromo-1-(3-chloro-4-fluorophenylamino)-5-
cyclopropyl-8-[3-(pyrrolidin-1-yl)propoxy]-5H-
pyridazino[4,5-b]indole oxalate 9
Yield: 83%; mp. 167–1698C; MS [MH+] (m/z): 558.1 (Br = 79), 560.1
(Br = 81); 1H-NMR (DMSO-d6) d: 9.29 (s, 1H, C4-H), 8.02 (s, 2H, C6, 9
-
H), 7.97 (dd, 1H, J = 6.5, 2.4 Hz, ph-H), 7.65 (brs, 1H, ph-H), 7.39 (t,
1H, J = 9.0 Hz ph-H), 4.25 (t, 2H, J = 5.8 Hz, CH2CH2CH2O), 3.47 (m,
1H, NCH), 3.38 (brs, 4H, pyrrolidinyl-2,5-2H), 3.31 (brs, 2H,
NCH2CH2CH2), 2.24 (brs, 2H, CH2CH2CH2), 1.97 (brs, 4H, pyrroli-
dinyl-2,5-2H), 1.34 (m, 2H, CH2CH2), 1.08 (m, 2H, CH2CH2); Anal.
Calcd. for C26H26BrClFN5O N C2H2O4: C 51.83, H 4.35, N 10.79;
Found: C 51.72, H 4.39, N 10.62.
7-Bromo-1-(4-trifluoromethylphenylamino)-5-cyclopropyl-
8-[3-(4-morpholinyl)propoxy]-5H-pyridazino[4,5-b]indole
oxalate 14
Yield: 82%; mp. 143–1458C; MS [MH+] (m/z): 590.2 (Br = 79), 592.2
(Br = 81); 1H-NMR (DMSO-d6) d: 9.42 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
7.79–7.77 (d, 3H, C9-H, ph-2H), 7.67 (d, 2H, J = 8.6 Hz, ph-2H), 4.13
(t, 2H, J = 5.8 Hz, CH2CH2CH2O), 3.81 (s, 4H, morpholinyl-3,5-2H),
3.52 (m, 1H, NCH), 3.17 (brs, 6H, morpholinyl-2,6-2H,
NCH2CH2CH2), 2.18 (brs, 2H, CH2CH2CH2), 1.36 (m, 2H, CH2CH2),
1.11 (m, 2H, CH2CH2); Anal. Calcd. for C27H27BrF3N5O2 N C2H2O4: C
51.19, H 4.30, N 10.29; Found: C 51.37, H 4.38, N 10.42.
7-Bromo-1-(3-chloro-4-fluorophenylamino)-5-
cyclopropyl-8-[3-(4-morpholinyl)propoxy]-5H-
pyridazino[4,5-b]indole oxalate 10
Yield: 84%; mp. 125–1278C; MS [MH+] (m/z): 574.2 (Br = 79), 576.2
(Br = 81); 1H-NMR (DMSO-d6) d: 9.33 (s, 1H, C4-H), 8.05 (s, 1H, C6-H),
8.03 (s, 1H, C9-H), 7.97 (d, 1H, J = 6.8 Hz, ph-H), 7.68 (brs, 1H, ph-H),
7.41 (t, 1H, J = 9.1 Hz ph-H), 4.25 (t, 2H, J = 5.6 Hz, CH2CH2CH2O),
3.83 (s, 4H, morpholinyl-3,5-2H), 3.50 (m, 1H, NCH), 3.21 (brs, 6H,
morpholinyl-2,6-2H, NCH2CH2CH2), 2.22 (brs, 2H, CH2CH2CH2),
1.35 (m, 2H, CH2CH2), 1.09 (m, 2H, CH2CH2); Anal. Calcd. for
C26H26BrClFN5O2 N C2H2O4: C 50.58, H 4.24, N 10.53; Found: C
50.32, H 4.36, N 10.35.
7-Bromo-1-(4-trifluoromethylphenylamino)-5-cyclopropyl-
8-[3-(piperidin-1-yl)propoxy]-5H-pyridazino[4,5-b]indole
oxalate 15
Yield: 85%; mp. 134–1358C; MS [MH+] (m/z): 588.2 (Br = 79), 590.2
(Br = 81); 1H-NMR (DMSO-d6) d: 9.41 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
7.81–7.78 (d, 3H, C9-H, ph-2H), 7.67 (d, 2H, J = 8.6 Hz, ph-2H), 4.15
(t, 2H, J = 5.7 Hz, CH2CH2CH2O), 3.51 (m, 5H, NCH, piperidinyl-
2,6-2H), 2.99 (brs, 2H, NCH2CH2CH2), 2.23 (brs, 2H, CH2CH2CH2),
1.77 (brs, 6H, piperidinyl-3,4,5-2H), 1.36 (m, 2H, CH2CH2), 1.11
(m, 2H, CH2CH2); Anal. Calcd. for C28H29BrF3N5O N C2H2O4: C 53.11,
H 4.61, N 10.32; Found: C 53.38, H 4.45, N 10.47.
7-Bromo-1-(3-chloro-4-fluorophenylamino)-5-
cyclopropyl-8-[3-(piperidin-1-yl)propoxy]-5H-
pyridazino[4,5-b]indole oxalate 11
Yield: 86%; mp. 122–1248C; MS [MH+] (m/z): 572.1 (Br = 79), 574.1
(Br = 81); 1H-NMR (DMSO-d6) d: 9.32 (s, 1H, C4-H), 8.05 (s, 1H, C6-H),
8.03 (s, 1H, C9-H), 7.96 (d, 1H, J = 6.8 Hz, ph-H), 7.68 (brs, 1H, ph-
H), 7.41 (t, 1H, J = 8.9 Hz ph-H), 4.25 (t, 2H, J = 5.7 Hz,
CH2CH2CH2O), 3.50 (m, 5H, NCH, piperidinyl-2,6-2H), 2.96 (brs,
2H, NCH2CH2CH2), 2.25 (brs, 2H, CH2CH2CH2), 1.78 (brs, 6H, piper-
idinyl-3,4,5-2H), 1.35 (m, 2H, CH2CH2), 1.09 (m, 2H, CH2CH2);
Anal. Calcd. for C27H28BrClFN5O N C2H2O4: C 52.54, H 4.56, N
10.56; Found: C 52.17, H 4.12, N 10.72.
7-Bromo-1-(3,4-difluorophenylamino)-5-cyclopropyl-8-[3-
(dimethylamino)propoxy]-5H-pyridazino[4,5-b]indole
oxalate 16
Yield: 81%; mp. 160–1628C; MS [MH+] (m/z): 516.4 (Br = 79), 518.4
(Br = 81); 1H-NMR (DMSO-d6) d: 9.34 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
8.04 (s, 1H, C9-H), 7.85–7.77 (m, 1H, ph-H), 7.46–7.40 (m, 2H, ph-
H), 4.26 (t, 2H, J = 5.5 Hz, CH2CH2CH2O), 3.51 (m, 1H, NCH), 3.30 (t,
2H, J = 7.1 Hz, NCH2CH2CH2), 2.85 (s, 6H, N(CH3)2), 2.24 (brs, 2H,
CH2CH2CH2), 1.35 (m, 2H, CH2CH2), 1.08 (m, 2H, CH2CH2); Anal.
Calcd. for C24H24BrF2N5O N C2H2O4: C 51.50, H 4.32, N 11.55;
Found: C 51.31, H 4.43, N 11.32.
7-Bromo-1-(4-trifluoromethylphenylamino)-5-cyclopropyl-
8-[3-(dimethylamino)propoxy]-5H-pyridazino[4,5-b]indole
oxalate 12
7-Bromo-1-(3,4-difluorophenylamino)-5-cyclopropyl-8-[3-
(pyrrolidin-1-yl)propoxy]-5H-pyridazino[4,5-b]indole
Yield: 84%; mp. 164–1668C; MS [MH+] (m/z): 548.2 (Br = 79), 550.2
(Br = 81); 1H-NMR (DMSO-d6) d: 9.40 (s, 1H, C4-H), 8.05 (s, 1H, C6-H),
7.83–7.79 (d, 3H, C9-H, ph-2H), 7.67 (d, 2H, J = 8.5 Hz, ph-2H), 4.16
(t, 2H, J = 5.5 Hz, CH2CH2CH2O), 3.50 (m, 1H, NCH), 3.31 (t, 2H, J =
7.0 Hz, NCH2CH2CH2), 2.85 (s, 6H, N(CH3)2), 2.23 (brs, 2H,
CH2CH2CH2), 1.34 (m, 2H, CH2CH2), 1.09 (m, 2H, CH2CH2); Anal.
Calcd. for C25H25BrF3N5O.C2H2O4: C 50.80, H 4.26, N 10.97; Found:
C 50.52, H 4.35, N 11.05.
oxalate 17
Yield: 83%; mp. 151–1528C; MS [MH+] (m/z): 542.4 (Br = 79), 544.3
(Br = 81); 1H-NMR (DMSO-d6) d: 9.34 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
8.02 (s, 1H, C9-H), 7.87–7.80 (m, 1H, ph-H), 7.46–7.37 (m, 2H, ph-
H), 4.26 (t, 2H, J = 5.5 Hz, CH2CH2CH2O), 3.51 (m, 1H, NCH), 3.42–
3.35 (m, 6H, pyrrolidinyl-2,5-2H, NCH2CH2CH2), 2.23 (brs, 2H,
CH2CH2CH2), 1.97 (brs, 4H, pyrrolidinyl-2,5-2H), 1.35 (m, 2H,
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Arch. Pharm. Chem. Life Sci. 2007, 340, 424–428
CH2CH2), 1.09 (m, 2H, CH2CH2); Anal. Calcd. for C26H26BrF2N5O N
cultured for 12 h at 378C and 5% CO2, cells were incubated with
various concentrations of samples for 24 h. MTT (3-(4,5-Dime-
thylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) was added at
a terminal concentration of 5 lg/mL and incubated with cells
for 4 h. The formazane crystals were dissolved in 100 lL DMSO
each well, and the optical density was measured at 492 nm (for
absorbance of MTT formazane) and 630 nm (for the reference
wavelength). The IC50 was calculated by Bliss [11].
C2H2O4: C 53.17, H 4.46, N 11.07; Found: C 53.36, H 4.55, N 10.95.
7-Bromo-1-(3,4-difluorophenylamino)-5-cyclopropyl-8-[3-
(4-morpholinyl)propoxy]-5H-pyridazino[4,5-b]indole
oxalate 18
Yield: 82%; mp. 143–1458C; MS [MH+] (m/z): 558.5 (Br = 79), 560.5
(Br = 81); 1H-NMR (DMSO-d6) d: 9.34 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
8.02 (s, 1H, C9-H), 7.86–7.77 (m, 1H, ph-H), 7.46–7.37 (m, 2H, ph-
H), 4.25 (t, 2H, J = 5.7 Hz, CH2CH2CH2O), 3.83 (s, 4H, morpholinyl-
3,5-2H), 3.51 (m, 1H, NCH), 3.24 (brs, 6H, morpholinyl-2,6-2H,
NCH2CH2CH2), 2.24 (brs, 2H, CH2CH2CH2), 1.35 (m, 2H, CH2CH2),
1.09 (m, 2H, CH2CH2); Anal. Calcd. for C26H26BrF2N5O2 N C2H2O4: C
51.86, H 4.35, N 10.80; Found: C 51.37, H 4.48, N 10.49.
References
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7-Bromo-1-(3,4-difluorophenylamino)-5-cyclopropyl-8-[3-
(4-morpholinyl)propoxy]-5H-pyridazino[4,5-b]indole
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oxalate 19
[4] J. B. Smaill, B. D. Palmer, G. W. Rewcastle, W. A. Denny, et
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Yield: 82%; mp. 138–1408C; MS [MH+] (m/z): 556.4 (Br = 79), 558.4
(Br = 81); 1H-NMR (DMSO-d6) d: 9.34 (s, 1H, C4-H), 8.06 (s, 1H, C6-H),
8.02 (s, 1H, C9-H), 7.85–7.76 (m, 1H, ph-H), 7.46–7.37 (m, 2H, ph-
H), 4.25 (t, 2H, J = 5.8 Hz, CH2CH2CH2O), 3.50 (m, 5H, NCH, piper-
idinyl-2,6-2H), 3,00 (brs, 2H, NCH2CH2CH2), 2.25 (brs, 2H,
CH2CH2CH2), 1.77 (brs, 6H, piperidinyl-3,4,5-2H), 1.35 (m, 2H,
CH2CH2), 1.09 (m, 2H, CH2CH2); Anal. Calcd. for C27H28BrF2N5O N
C2H2O4: C 53.88, H 4.68, N 10.83; Found: C 53.68, H 4.47, N 10.57.
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i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com