10370
Y.A. Ibrahim et al. / Tetrahedron 64 (2008) 10365–10374
2927, 1694, 1460, 1281, 1088, 846, 756, 701. 1H NMR (DMSO-d6):
8.04 (d, 2H, J 8.6), 7.67 (d, 2H, J 8.6), 7.35–7.29 (m, 4H), 7.23 (t, 1H, J
7.2), 4.35 (s, 2H, CH2), 4.09 (s, 2H, CH2). 13C NMR (DMSO-d6):
158.8, 158.5, 151.7, 149.1, 137.6, 136.9, 132.0, 129.9, 129.5, 129.46,
128.6, 126.9, 37.2, 22.0. Anal. Calcd for C18H13ClN4OS (368.9): C
58.62; H 3.55; N 15.19; S 8.69. Found: C 58.41; H 3.61; N 14.92; S
8.39.
4.4.6. 3-Benzyl-7-p-methoxyphenyl-1H-pyrazolo[5,1-
c][1,2,4]triazin-4-one 9c
d
Colourless crystals from DMF, yield 0.22 g (66%), mp 308 ꢀC.
HRMS: m/z¼332.1267 (calcd for C19H16N4O2: 332.1267). IR: 3243,
3140, 3029, 2931, 2832, 1678, 1611, 1531, 1454, 1434, 1252, 1174,
d
1033, 992, 832, 773, 746, 698. 1H NMR (DMSO-d6):
d 13.83 (s, 1H,
NH), 7.97 (d, 2H, J 8.8), 7.30 (m, 4H), 7.22 (m, 1H), 7.04 (d, 2H, J 8.8),
6.66 (s, 1H), 4.06 (s, 2H, CH2), 3.82 (s, 3H, OCH3). 13C NMR (DMSO-
4.4. Procedure for pyrolysis of 5–7, 20 and 24. Pyrolytic
synthesis of 8–10, 21a–c and 30e: general procedures
d6): d 160.6, 155.4, 149.5, 144.6, 138.6, 138.2, 129.1, 128.6, 128.3,
126.6, 124.3, 114.5, 83.6, 55.5, 35.7.
Each of compounds 5–7, 20 and 24e (1 mmol) was introduced in
the reaction tube, cooled in liquid nitrogen, sealed under vacuum
(0.06 mbar) and placed in the pyrolyzer at 230 ꢀC (static pyrolyzer)
for 45 min. After cooling, the contents of the tube were dissolved
and crystallized from the proper solvent to give the corresponding
compounds 8–10, 21ac and 30e.
4.4.7. 7-p-Chlorophenyl-1H-pyrazolo[5,1-c][1,2,4]triazin-
4-one 10a
Brown crystals from DMF, yield 0.21 g (85%), mp >370 ꢀC.
HRMS: m/z¼246.0302 (calcd for C11H7ClN4O: 246.0308). IR: 3180,
3147, 1676, 1604, 1441, 1092, 1013, 835. 1H NMR (DMSO-d6):
d 14.20
(s, 1H, NH), 8.07 (d, 2H, J 7.6), 7.61 (s, 1H), 7.56 (d, 2H, J 7.6), 6.85 (s,
1H). 13C NMR (DMSO-d6):
d 153.6, 149.1, 144.0, 134.2, 130.4, 128.9,
4.4.1. 7-Phenyl-1H-pyrazolo[5,1-c][1,2,4]triazin-4-one 8a
128.6, 128.3, 84.9.
Brown crystals from EtOH/DMF, yield 0.13 g (61%), mp 324–
325 ꢀC. HRMS: m/z¼212.0693 (calcd for C11H8N4O: 212.0693). IR:
3235, 3166, 3138, 3059, 1696, 1611, 1536, 1458, 1444, 1374, 762, 692.
4.4.8. 7-p-Chlorophenyl-3-methyl-1H-pyrazolo[5,1-c][1,2,4]triazin-
4-one 10b
1H NMR (DMSO-d6):
d
14.10 (s, 1H, NH), 8.05 (d, 2H, J 8.4), 7.60 (s,
1H), 7.53–7.47 (m, 3H), 6.82 (s, 1H, CH8). 13C NMR (DMSO-d6):
155.3, 149.6, 144.4, 132.0, 130.1, 129.3, 129.1, 127.1, 85.2.
Colourless crystals from acetone, yield 0.18 g (69%), mp >360 ꢀC.
HRMS: m/z¼260.0458 (calcd for C12H9ClN4O: 260.0459). IR: 3196,
3178, 3071, 2921, 1665, 1607, 1591, 1447, 1269, 1091, 1013, 834, 819,
d
774, 741. 1H NMR (DMSO-d6):
d
13.75 (s, 1H, NH), 8.07 (d, 2H, J 8.4),
7.57 (t, 2H, J 8.4), 6.74 (s, 1H), 2.32 (s, 3H, CH3). 13C NMR (DMSO-d6):
154.4, 150.2, 145.2, 137.1, 134.6, 131.1, 129.4, 128.8, 84.1, 16.7.
4.4.2. 3-Methyl-7-phenyl-1H-pyrazolo[5,1-c][1,2,4]triazin-
4-one 8b
d
Brown crystals from DMF, yield 0.21 g (93%), mp 350 ꢀC. LCMS:
m/z¼227
12H10N4O¼226.0849). IR: 3208, 3067, 3001, 2925,1673,1606,1461,
1442, 1271, 761, 692. 1H NMR (DMSO-d6):
13.71 (s, 1H, NH), 8.02
(Mþ1),
HRMS:
m/z¼226.0849
(calcd
for
4.4.9. 3-Benzyl-7-p-chlorophenyl-1H-pyrazolo[5,1-c][1,2,4]triazin-
4-one 10c
Colourless crystals from DMF, yield 0.27 g (80%), mp 310 ꢀC.
HRMS: m/z¼336.0772 (calcd for C18H13ClN4O: 336.0772). IR: 3239,
3143, 3064, 2959, 1680, 1611, 1540, 1493, 1451, 1431, 1329, 1267,
1162, 1092, 1014, 992, 832, 773, 749, 698. 1H NMR (DMSO-d6):
C
d
(d, 2H, J 7.2), 7.50 (t, 2H, J 7.2), 7.46 (t, 1H, J 7.2), 6.68 (s, 1H), 2.32 (s,
3H, CH3). 13C NMR (DMSO-d6):
d 155.6, 150.2, 145.1, 136.9, 132.1,
130.0, 129.3, 127.0, 83.9, 16.7.
d
13.92 (s, 1H, NH), 8.06 (d, 2H, J 8.4), 7.56 (d, 2H, J 8.4), 7.31 (m, 4H),
7.22 (t, 1H, J 6.8), 6.79 (s, 1H), 4.07 (s, 2H, CH2). 13C NMR (DMSO-d6):
154.0, 149.2, 144.5, 138.5, 137.8, 134.2, 130.5, 128.9, 128.8, 128.31,
4.4.3. 3-Benzyl-7-phenyl-1H-pyrazolo[5,1-c][1,2,4]triazin-4-one 8c
Colourless crystals from DMF, yield 0.18 g (60%), chars at 300 ꢀC.
HRMS: m/z¼302.1163 (calcd for C18H14N4O: 302.1162). IR: 3239,
3145, 3083, 2929, 1681, 1614, 1541, 1459, 1447, 1204, 1164, 993, 763,
d
128.3, 126.3, 84.1, 35.4.
747, 689. 1H NMR (DMSO-d6):
d
13.90 (s, 1H, NH), 8.03 (d, 2H, J 7.2),
7.52–7.44 (m, 3H), 7.34–7.29 (m, 4H), 7.22 (t, 1H, J 6.8), 6.75 (s, 1H),
4.07 (s, 2H, CH2). 13C NMR (DEPT) (DMSO-d6):
155.4 (C), 149.5 (C),
4.4.10. 2-Phenyl-4H-pyrazolo[5,1-b]quinazolin-9-one 21a
Colourless crystals from ethanol, yield 0.16 g (60%), mp 292–
293 ꢀC (lit.12 mp 290 ꢀC). LCMS: m/z¼262 (Mþ1). IR: 3182, 3150,
3110, 3068, 3021, 1679, 1652, 1636, 1574, 1469, 1349, 1331, 748. 1H
d
144.6 (C), 138.7 (C), 138.1 (C), 131.8 (C), 129.8 (CH), 129.14 (2CH),
129.12 (2CH), 128.5 (2CH), 126.8 (2CH), 126.6 (CH), 84.1 (CH), 35.6
(CH2).
NMR (DMSO-d6):
7.8), 7.77 (t, 1H, J 7.8), 7.50 (t, 2H, J 7.8), 7.44 (t, 1H, J 7.2), 7.43 (d, 1H, J
7.8), 7.28 (t, 1H, J 7.8), 6.59 (s, 1H). 13C NMR (DMSO-d6):
155.5,
d 12.37 (s, 1H, NH), 8.22 (d, 1H, J 7.8), 8.04 (d, 2H, J
d
4.4.4. 7-p-Methoxyphenyl-1H-pyrazolo[5,1-c][1,2,4]triazin-
4-one 9a
154.8,143.2,139.6,134.6,132.1,129.1,128.6,127.5,126.3,121.3,115.9,
111.6, 84.1. HRMS: 261.0897 (calcd for C16H11N3O¼261.0897).
Brown crystals from DMF, yield 0.12 g (50%), chars at 274 ꢀC.
HRMS: m/z¼242.0797 (calcd for C12H10N4O2: 242.0798). IR: 3179,
3146, 2936, 1681, 1607, 1578, 1527, 1452, 1437, 1289, 1256, 1178,
4.4.11. 2-p-Methoxyphenyl-4H-pyrazolo[5,1-b]quinazolin-
9-one 21b
1030, 836, 767. 1H NMR (DMSO-d6):
d
14.09 (s, 1H, NH), 7.99 (d, 2H, J
Colourless crystals from ethanol, yield 0.10 g (34%), mp >300 ꢀC
(lit.12 mp 280 ꢀC). HRMS: m/z¼291.1002 (calcd for C17H13N3O2:
8.8), 7.58 (s, 1H), 7.06 (d, 2H, J 8.8), 6.75 (s, 1H), 3.83 (s, 3H, CH3). 13
C
NMR (DMSO-d6):
d
160.7, 155.0, 149.4, 144.1, 128.9, 128.4, 124.2,
291.1002). 1H NMR (DMSO-d6):
d 12.34 (s,1H, NH), 8.21 (d,1H, J 8.0),
114.5, 84.4, 55.5.
7.98 (d, 2H, J 8.4), 7.76 (t, 1H, J 8.0), 7.42 (t, 1H, J 8.0), 7.27 (d, 1H, J
8.0), 7.05 (d, 2H, J 8.4), 6.52 (s, 1H), 3.83 (s, 3H).
4.4.5. 3-Methyl-7-p-methoxyphenyl-1H-pyrazolo[5,1-
c][1,2,4]triazin-4-one 9b
4.4.12. 2-p-Chlorophenyl-4H-pyrazolo[5,1-b]quinazolin-9-one 21c
Colourless crystals from ethanol, yield 0.15 g (50%), mp >350 ꢀC
(lit.12 mp 280 ꢀC). MS: m/z¼295 (Mþ), 297 (Mþ2). HRMS¼295.0506
Brown crystals from DMF, yield 0.14 g (53%), mp 326 ꢀC. HRMS:
m/z¼256.0954 (calcd for C13H12N4O2: 256.0954). IR: 3187, 2998,
2930, 2837, 1670, 1608, 1505, 1453, 1437, 1256, 1176, 1033, 838, 771.
(C16H10ClN3O requires 295.0507). 1H NMR (DMSO-d6):
d 12.45 (s,
1H NMR (DMSO-d6):
d
13.65 (s, 1H, NH), 7.97 (d, 2H, J 7.6), 7.04 (d,
2H, J 7.6), 6.61 (s, 1H), 3.82 (s, 3H, OCH3), 2.31 (s, 3H, CH3). 13C NMR
(DMSO-d6): 160.6, 155.2, 149.9, 144.8, 136.6, 128.3, 124.4, 114.4,
83.1, 55.5, 16.5.
1H, NH), 8.22 (d, 1H, J 8.0), 8.08 (d, 2H, J 8.4), 7.78 (t, 1H, J 8.0), 7.57
(d, 2H, J 8.4), 7.43 (t,1H, J 8.0), 7.29 (t,1H, J 8.0), 6.64 (s,1H). 13C NMR
d
(DMSO-d6):
d 155.6, 153.7, 143.2, 139.7, 134.8, 133.8, 129.3, 128.8,
128.5, 127.6, 121.5, 116.0, 111.6, 84.3.