Sep-Oct 2006
Synthesis of Pyrazolo[3,4-d]pyrimidine, Pyrazolo[3,4-b][1,6]naphthyridine
1173
131.534.3, 137.8, 139.6, 142.3, 150.3, 153.4, (24 ArC); ms: (m/z),
494 (M+), 416, 402, 297.
Anal. Calcd. for C28H23BrN4: C, 67.88; H, 4.68; N; 11.31.
Found: C, 67.96; H, 4.85; N, 11.52.
This compound was obtained from pyrazolecarbaldehyde 1a
(0.60 g, 2 mmol) and methyl-1-cyclohexanone (7b) (0.24 mL, 2
mmol) using the method described for 8a; the yield was 0.62 g
(83%) colorless prisms, mp 126-127 °C (ethyl acetate); ir: 1739,
1598, 1552 cm-1; 1H nmr: ꢀ 1.55 (d, J=7.2Hz, 3H, CH3), 1.99 (m,
2H, CH2), 2.15 (m, 2H, CH2), 2.96 (t, 2H, J = 7.8 Hz, CH2), 3.11
(q, J =7.2 Hz, 1H, C8-H), 7.27-7.54 (m, 5H, Ph) 7.96 (d, J = 8.4
Hz, 2H, ArH), 7.99 (s, 1H, C4-H), 8.46 (d, J = 8.4 Hz, 2H,
Ar);13C nmr :ꢀ, 21.3, 29.8, 30.0, 31.6, 36.9, 113.5, 120.3, 125.2,
126.9, 128.2, 128.7, 128.9, 129.3, 131.6, 134.1, 139.8, 141.8,
150.1, 162.1 (18 ArC); ms: (m/z) 373 (M+), 352, 337.
3-(4-Chlorophenyl)-8-methoxy-1-phenyl-5,6,7,8-tetrahydro-1H-
benzo[h]pyrazolo[3,4-b]quinoline (6a).
A solution of 1a (0.60 g, 2 mmol) and 6-methoxy-1-tetralone
(0.35 g, 2 mmol) in ethanolic potassium hydroxide (10 mL, 2%)
was heated at reflux temperature for one hour. The mixture was
cooled to room temperature, and the solid obtained was
collected by suction filtration and washed with ethanol. The
yield was 0.60 g (68%), colorless prisms, mp 194-195° (ethyl
Anal. Calcd. for C23H20ClN3: C, 73.89; H, 5.39; N; 11.24.
Found: C, 73.96; H, 5.58; N, 11.52.
1
acetate); ir: 2339, 1597, 1550 cm-1; H nmr: ꢀ 2.97 (t, J=7Hz,
3-(4-Bromophenyl)-1-phenyl-5,6,7,8-tetrahydro-1H-pyrazolo-
[3,4-b]quinoline (8c).
2H, CH2), 3.06 (t, J=7Hz, 2H, CH2), 3.87 (s, 3H, OCH3), 6.77
(d, J = 8.4 Hz, 1H, C7H), 6.96(dd, J = 8.4 , 1 Hz, 1H, C9H),
7.15-7.48(m, 5H, Ph), 7.82 (dd, J=8.4, 0.9Hz,1H, C10H), 7.95 (d,
J = 8.4 Hz, 2H, ArH), 8.01(s, 1H, C4H), 8.53 (d, J=8.4Hz, 2H,
ArH), 13C nmr: ꢀ 29.8, 30.2, 52.8, 114.6, 120.4, 121.7, 122.4,
124.6, 125.6, 126.4, 127.3, 127.7, 128.4, 128.6, 129.4, 131.3,
134.2, 137.7, 142.5, 148.4, 154.6, 159.2, (24 ArC); ms (m/z),
437 (M+), 422, 255, 218, 179.
This compound was obtained from 1b (0.68 g, 2 mmol) and
cyclohexanone (7a) (0.21 mL, 2 mmol) using the method
described for 8a; yield 0.46 g (76%), colorless prisms, mp 168-
169 °C (ethyl acetate); ir: 1741, 1596, 1551 cm-1; 1H nmr: ꢀ 1.63
(t, J=7Hz, 2H, CH2), 1.83 (m, 2H, CH2), 1.95 (m, 2H, CH2), 2.8
(t, J=7Hz, 2H, CH2), 7.25-7.52 (m, 5H, Ph) 7.93 (d, J = 8.4 Hz,
2H, ArH), 7.96 (s, 1H, C4-H), 8.45 (d, J = 8.4 Hz, 2H, ArH); 13
C
Anal. Calcd. for C27H20ClN3O: C, 74.05; H, 4.60; N, 9.60.
Found: C, 74.24; H, 4.72; N, 9.76.
nmr: ꢀ 29.9, 31.8, 31.9, 113.5, 120.4, 125.2, 126.6, 128.1, 128.6,
128.9, 129.3, 131.5, 134.2, 139.7, 141.8, 150.3, 162.3 (18 ArC);
ms: (m/z) 403 (M+), 385, 370.
Anal. Calcd. for C22H18BrN3: C, 65.36; H, 4.49; N; 10.39.
Found: C, 65.56; H, 4.86; N, 10.26.
3-(4-Bromophenyl)-8-methoxy-1-phenyl-5,6,7,8-tetrahydro-1H-
benzo[h]pyrazolo[3,4-b]quinoline (6b).
A mixture of 1b (0.68 g, 2 mmol) and 6-methoxy-1-tetralone
(0.35 g, 2 mmol) was reacted by the method described for 6a;
yield 0.64 g (66%), colorless prisms, mp 198-199 °C (ethyl
3-(4-Bromophenyl)-8-methyl-1-phenyl-5, 6, 7, 8-tetrahydro-1H-
pyrazolo[3,4-b]quinoline (8d).
1
acetate); ir: 2341, 1595, 1551 cm-1; H nmr: ꢀ 2.99 (t, J=7Hz,
This compound was obtained from 1b (0.68 g, 2 mmol) and 2-
methyl-1-cyclohexanone (7b) (0.24 mL, 2 mmol) using the
method described for 8a; yield 0.67 g, (82%); colorless prisms;
2H, CH2), 3.15 (t, J=7Hz, 2H, CH2), 3.88 (s, 3H, OCH3), 6.78 (d,
J = 8.4 Hz, 1H, C7H), 6.97 (dd, J=8.4, 0.9Hz, 1H, C9H), 7.15-
7.48 (m, 5H, Ph), 7.83 (dd, J = 8.4, 0.9 Hz, 1H, C10-H), 7.99 (d, J
= 8.4 Hz, 2H, ArH), 8.02 (s, 1H, C4H), 8.46 (d, J=8.4Hz, 2H,
ArH). 13C nmr: ꢀ 29.9, 30.4, 52.9, 114.7, 120.5, 121.9, 122.6,
124.7, 125.4, 125.7, 126.5, 127.4, 127.9, 128.6, 128.7, 129.5,
131.4, 134.4, 137.9, 142.5, 148.7, 154.7, 159.4 (24 ArC); ms:
(m/z), 481 (M+), 466, 299, 262, 223.
1
mp 131-132 °C (ethyl acetate); ir: 1740, 1597, 1552 cm-1; H
nmr: ꢀ 1.60 (d, J=7Hz, 3H, CH3), 1.66 (m, 2H, CH2), 1.85 (m,
2H, CH2), 1.97 (t, J = 6.9 Hz, 2H, CH2), 3.09 (q, J = 6.9 Hz,
1H, C8-H), 7.24-7.63 (m, 5H, Ph) 7.89 (d, J = 8.4 Hz, 2H, ArH),
7.96 (s, 1H, C4-H), 8.46 (d, J = 8.4 Hz, 2H, ArH); 13C nmr : ꢀ
21.4, 29.9, 30.2, 31.7, 36.9, 113.7, 120.5, 126.9, 128.8, 128.9,
129.4, 131.7, 134.3, 139.9, 141.9, 150.2, 162.3 (18 ArC); ms:
(m/z) 417 (M+), 396, 381.
Anal. Calcd. for C27H20BrN3O: C, 67.23; H, 4.18; N; 8.71.
Found: C, 67.36; H, 4.38; N, 8.92.
3-(4-Chlorophenyl)-1-phenyl-5,6,7,8-tetrahydro-1H-pyrazolo-
[3,4-b]quinoline (8a).
Anal. Calcd. for C23H20BrN3: C, 66.04; H, 4.82; N; 10.04.
Found: C, 66.16; H, 4.95; N, 10.12.
A solution of 1a (0.60 g, 2 mmol) and cyclohexanone (7a)
(0.21 g, 2 mmol) in ethanolic potassium hydroxide (10 mL, 2%)
was reflux for one hour. The mixture was then cooled to room
temperature and the solid obtained was collected by filtration
and washed with ethanol. The yield was 0.56 g (78%), colorless
prisms, mp 160-161° (ethyl acetate); ir: 1742, 1605, 1510 cm-1;
1H nmr: ꢀ 1.65 (t, J=7Hz, 2H, CH2), 1.85 (m, 2H, CH2), 1.99
(m, 2H, CH2), 2.96 (t, J=7H, 2H, CH2), 7.27-7.54 (m, 5H, Ph)
7.96 (d, J = 8.4 Hz, 2H, ArH), 7.99 (s, 1H, C4-H), 8.46(d, J=8.4
Hz, 2H, ArH). 13C nmr: ꢀ 29.8, 31.6, 31.9, 113.4, 120.2, 125.1,
126.7, 128.1, 128.8, 129.2, 131.4, 134.0, 139.6, 141.7, 150.1,
162.2 (18 ArC); ms: (m/z), 359 (M+), 341, 326.
3-(4-Chlorophenyl)-7,7-dimethyl-1-phenyl-1,6,7,8-tetrahydro-
5H-pyrazolo[3,4-b]quinolin-5-one (9a).
A mixture of 1a (0.60 g, 2 mmol) and dimedone (0.28 g, 2
mmol) was heated at 140-150 °C for half an hour. The solid
obtained on cooling was stirred in ethanol (2 mL) for 10
minutes. The solid obtained was collected by filtration and
washed with cold ethanol (5 mL). Yield 0.61 g (76%), colorless
prisms, mp 197-198 °C (ethyl acetate); ir: 1728, 1592, 1556
1
cm-1; H nmr: ꢀ 1.19 (s, 6H, 2CH3), 2.69 (s, 2H, CH2), 3.24 (s,
2H, CH2), 7.39-7.62 (m, 5H, Ph) 8.06 (d, J = 8.4 Hz, 2H, ArH),
8.40 (d, J=8.4 Hz, 2H, ArH), 9.06 (s, 1H, C4-H). 13C nmr :ꢀ,
28.3, 32.9, 47.4, 52.3, 114.5, 121.2, 122.8, 126.3, 128.3, 129.1,
130.3, 130.7, 137.7, 138.8, 162.4, (18 Ar C), 197.0 (C=O); ms:
(m/z) 401 (M+), 345, 282.
Anal. Calcd. for C22H18ClN3: C, 73.63; H, 5.04; N, 11.68.
Found: C, 73.87; H, 5.28; N, 11.84.
Anal. Calcd. for C24H20ClN3O: C, 71.73; H, 5.02; N, 10.46.
Found: C, 71.82; H, 5.23; N, 10.68.
3-(4-Chlorophenyl)-8-methyl-1-phenyl-5,6,7,8-tetrahydro-1H-
pyrazolo [3,4-b]quinoline (8b).