Jul-Aug 2002
Synthesis and Characterization of some N-Mannich Bases of [1,2,3]Triazoloquinolines
637
Mass spectra were obtained with a Mat 112 Varian Mat Bremen
(70Ev) mass spectrometer and Applied Biosystems Mariner System
5220 LC/MS (nozzle potential 250.00). Column flash chromatogra-
phy was carried out on Merck silica gel (250-400 mesh ASTM);
reactions were monitored by analytical thin-layer chromatography
(TLC) using Merck silica gel 60 F-254 glass plates. Solutions were
concentrated in a rotary evaporator under reduced pressure. Starting
nitro-quinolines and the four secondary amines were purchased
from Aldrich Chimica and Janssen Chimica (now Acros) respec-
tively. P-methanesulfonamidoaniline was prepared by us [1].
ethyl acetate as solvent. After a time varying from 10 to 20 hours,
the catalyst was removed by filtration and the filtrate was evapo-
rated until dryness to give 2.07 g of product. Yield 96%; mp 73-
74°C (ethyl alcohol); rf 0.30 (TLC; ethyl acetate/n-hexane
1
70:30); H nmr (DMSO-d ) d: 1.25 (t, 3H, J=7.0Hz, CH ), 4.12
6
3
(q, 2H, J=7.0Hz, CH ), 5.68 (bs, 2H, NH ), 7.22 (d, 1H, J=8.8Hz,
2
2
CH-8), 7.38 (dd, 1H, J=8.7 and 4.1Hz, HC-3), 7.55 (d, 1H,
J=8.9Hz, HC-7), 8.58 (d, 1H, J=8.8 and 1.6Hz, HC-4), 8.75 (dd,
2H, J=4.1 and 1.6Hz, HC-2 and NH amid.).
Anal. Calcd. for C H N O : C, 62.33; H, 5.67; N, 18.17.
12 13
3 2
Found: C, 62.48; H, 5.37; N, 17.95.
Biological Activity.
Synthesis of Ethyl-3H-[1,2,3]-triazolo[4,5-f]quinoline-3-car-
boxylate (5).
Human cell lines (epitheloid carcinoma cervix: HeLa, hepato-
cellular carcinoma: Hep-G2, glioblastoma Aou-373, obtained
from the American Type Culture Collection) were plated at a den-
In a 100-ml round-bottomed flask, 1.9 g (8.2 mmoles) of 4
were dissolved in a 1:1 mixture of glacial acetic acid/water and
the red solution was cooled in an ice bath. A 2ml cold water solu-
tion of stoichiometric sodium nitrite (0.579 g. 8.4 mmoles) was
slowly added to the acetic acid solution, and the reaction mixture
was stirred at 0°C for 4-7 hours. In the meantime, a light precipi-
tate separated which was collected by filtration, washed and
3
sity of 5 x 10 cells/well with 100 µM of drugs in flat-bottomed
96-well culture plates. After incubation for 6 days, cell sensitivity
to the drugs was evaluated using the tetrazolium salt 3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)
kit (Roche). Cell viability was determined by comparing the num-
ber of viable cells with and without drugs. Data are the means of
three separate experiments (performed in triplicate) and results are
expressed as % reduction cell survival over controls [10].
dried. Yield 85%; mp 101°C (ethyl alcohol); rf 0.23 (TLC; ethyl
1
acetate/n-hexane 70:30); H nmr (DMSO-d ) d: 1.61 (t, 3H,
6
J=7.1Hz, CH ), 4.75 (q, 2H, J=7.1Hz, CH ), 7.7 (dd, 1H, J=4.6
3
2
General Procedure for Synthesis of Quinolinyl-6-carbamic Acid
Ethyl Esters 2 and 8.
and 8.3Hz, HC-8), 8.28 (d, 1H, J=9.2Hz, HC-5), 8.39 (d, 1H,
J=9.3Hz, HC-4), 9.06 (dd, 1H, J=1,7 and 4.4Hz, HC-7), 9.13 (dd,
1H, J=1.8 and 8.2Hz, HC-9).
An ethanol solution of starting nitro-compounds (3.00 g, 17.2
mmoles) was slowly added to 5% palladium on a charcoal
ethanol suspension saturated with hydrogen, and the mixture was
Anal. Calcd. for C H N O : C, 59.50; H, 4.16; N, 23.13.
12 10
4 2
Found: C, 59.33; H, 4.19, N, 23.36.
o
hydrogenated at atmospheric pressure and 40 C until the starting
Synthesis of [1,2,3]Triazolo[4,5-f]quinoline (6).
material disappeared at TLC analysis. After 1-2 h, the mixture
was filtered and the filtrate evaporated to dryness to give almost
pure crude solids 1 and 7 (2.6 g, 98 %) which were directly trans-
formed into urethane derivatives with ethyl chloroformate in
anhydrous THF. After some hours of stirring at room tempera-
ture, the solvent was removed in vacuum to yield 2.49 g of raw
material. Physical and spectroscopic data : see table 1.
In a 25-ml round-bottomed flask, 2.6 g (10.7 mmoles) of 5
were dissolved in 5-10 ml of 2N sodium hydroxide and the solu-
tion was refluxed for 1hour. After cooling, the reaction mixture
was acidified with dilute acetic acid and then extracted by ethyl
acetate. The organic phase was washed, dried with anhydrous
sodium sulfate and evaporated to dryness, yielding a white crys-
talline residue purified by flash chromatography (L 13 cm, i.d. 3
cm, acetone/dichloromethane 70:30 as eluent). Yield 96%; mp
Anal. Calcd. for 2 and 8, C H N O : C, 66.55; H, 5.59; N,
12 12
2 2
12.96. Found: C, 66.38; H, 5.73; N, 12.68; and C, 66.75; H, 5.56;
N, 12.88 respectively.
268-269°C (methyl alcohol) (lit.[14] 260°C); rf 0.26 (TLC; ethyl
1
acetate/n-exane 70:30); H nmr (DMSO-d ) d: 7.7 (dd, 1H, J=4.6
6
Synthesis of (5-nitro-quinolin-6-yl)-carbamic Acid Ethyl Ester (3).
and 8.3Hz, HC-8), 8.28 (d, 1H, J=9.2Hz, HC-5), 8.39 (d, 1H,
Quinolinyl-6-carbamic acid ethyl ester 2 (2.00 g, 9.24 mmoles)
was dissolved in 5 ml of cold conc. sulfuric acid, and then slowly
added to 3 ml of a 1:1 cold mixture of concentrated sulfuric
acid/fuming nitric acid. After about 30 minutes of stirring in an
ice bath, the mixture was poured into 50 ml ice/water and made
alkaline using dilute ammonium hydroxide. A yellow precipitate
formed, which was collected, washed and dried (1.4 g). Yield
69%; mp 97-98°C (methyl alcohol); rf 0.67 (TLC, ethyl
J=9.3Hz, HC-4), 9.06 (dd, 1H, J=1.7 and 4.4Hz, HC-7), 9.13 (dd,
13
1H, J=1.8 and 8.2Hz, HC-9); C nmr (DMSO-d ) d: 118.54
6
(2bs, 3C, C-8, C-9b and C3a)), 123.55 and 123.19 8(C-4),
129.19 (2bs, C-5), 131.31 and 131.04 (C-9), 137.03 (bs, C-9a),
147.84 (C-5a), 151.03 and 150,63 (C-7); uv (ethyl alcohol): lmax
nm 213, 249; lmin nm 229; ir (KBr): 2511 (NH), 1548,1401 (Ar)
-1
+
cm ; ms, m/z (relative abundance): 171.07 (C H N4 , 28%),
9
7
143.06 (C H N , 42%), 142.06 (C H N , 100%).
9
7
2
9 6 2
1
acetate/n-exane 70:30); H nmr (CDCl ), d: 1.36 (q, 3H,
Anal. Calcd. for C H N : C, 63.52; H, 3.55; N, 32.92. Found:
3
9
6 4
J=7.1Hz, CH ), 4.3 (q, 2H, J=7,1Hz, CH ), 7.56 (dd, 1H, J=4.2
C, 63.61; H, 3.55; N, 32.97.
3
2
and 8.8Hz, HC-3), 8.29 (d, 1H, J=8.5Hz, HC-7), 8.49 (dd, 1H,
J=1.6 and 8.7Hz, HC-4), 8.72 (d, 1H, J=8.5Hz, HC-8), 8.84 (bs,
1H, NH), 8.92 (dd, 1H, J=1.5 and 4.2Hz, HC-2 ).
Procedure for nitration of Compound 8.
In a 100-ml round-bottomed flask placed in an ice-bath, 1.2 g
(5.5 mmoles) of 8 were dissolved in 4 ml of previously cooled
(0°C) concentrated sulfuric acid and a 1:3 cold mixture of con-
centrated sulfuric acid/fuming nitric acid was added dropwise.
The mixture was stirred for 30 minutes at 0°C and was then
poured into 20 ml ice/water. After a short time, a yellow precipi-
tate separated out that was collected, washed and dried. This raw
Anal. Calcd. for C H N O : C, 55.17; H, 4.24; N, 16.09.
12 11
3 4
Found: C, 55.35; H, 4.21; N, 16.39.
Synthesis of (5-Amino-quinolin-6-yl)-carbamic Ethyl Ester (4).
By the same procedure adopted to obtain 1 and 7, compound 3
(2.2 g, 8.4 mmoles) was reduced to its amino-derivative using