Molecules 2011, 16
1884
13C-NMR (CDCl3) δ: 168.8, 162.1, 150.9, 149.6, 138.5, 131.1, 128.3, 126.6, 125.6, 121.7, 118.3,
104.6, 101.1, 60.4, 28.0, 21.2, 13.9. MS-ESI (m/z, relative intensity, %): 313 (M++3) (2), 312 (M++2)
(20), 311 (M++1) (100). IR (KBr, cm−1) ν: 3,453, 3,336 (NH2), 3,111 (ArH), 2,976, 2,926 (CH2 and
CH3), 1,662 (C=O), 1,590, 1,494, 1,462 (C=N and aromatic ring skeleton vibration), 1,262 (O-CH3).
Ethyl 4-amino-1-(4-chlorophenyl)-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (3l). Colorless
solid. m.p. 143–144 °C. 1H-NMR (CDCl3) δ: 8.27 (d, J = 6.6 Hz, 2H, Ar-H), 8.04 (s, 1H, pyrazole H),
7.43–7.49 (m, 2H, Ar-H), 6.74 (br, 2H, -NH2), 4.40 (q, J = 7.2 Hz, 2H, -CH2CH3), 2.81 (s, 3H, -CH3),
1.43 (t, J = 7.2 Hz, 3H, -CH2CH3). 13C-NMR (CDCl3) δ: 168.9, 162.0, 151.0, 135.3, 131.6, 130.9,
128.1, 121.1, 118.5, 104.5, 100.9, 60.3, 28.0, 13.9. MS-ESI (m/z, relative intensity, %): 334 (8), 333
(33), 331 (M++1) (100). IR (KBr, cm−1) ν: 3,453, 3,338 (NH2), 3,113 (ArH), 2,973, 2,925 (CH2 and
CH3), 1,660 (C=O), 1,593, 1,457 (C=N and aromatic ring skeleton vibration), 1,260 (O-CH3).
Ethyl
4-amino-1-(3-chlorophenyl)-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate
(3m).
1
Colorless solid. m.p. 105–106 °C. H-NMR (CDCl3) δ: 8.37–8.42 (m, 1H, Ar-H), 8.28–8.33 (m, 1H,
Ar-H), 8.04 (s, 1H, pyrazole H), 7.41–7.46 (m, 1H, Ar-H), 7.23–7.27 (m, 1H, Ar-H), 6.73 (br, 2H, -
NH2), 4.41 (q, J = 7.2 Hz, 2H, -CH2CH3), 2.83 (s, 3H, -CH3), 1.44 (t, J = 7.2 Hz, 3H, -CH2CH3). 13C-
NMR (CDCl3) δ: 168.7, 161.9, 150.9, 132.9, 131.6, 130.6, 130.2, 129.5, 128.6, 125.4, 121.8, 120.6,
118.5, 60.4, 27.9, 13.8. MS-ESI (m/z, relative intensity, %): 334 (6), 333 (31), 331 (M++1) (100). IR
(KBr, cm−1) ν: 3,453, 3,337 (NH2), 3,111 (ArH), 2,974, 2,928 (CH2 and CH3), 1,661 (C=O), 1,592,
1,490, 1,458 (C=N and aromatic ring skeleton vibration), 1,258 (O-CH3).
Ethyl 4-amino-1-(2-chlorophenyl)-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (3n). Colorless
1
solid. m.p. 164–165 °C. H-NMR (CDCl3) δ: 8.11 (s, 1H, Ar-H), 8.04 (s, 1H, pyrazole H), 7.51–7.57
(m, 1H, Ar-H), 7.38–7.42 (m, 2H, Ar-H), 6.83 (br, 2H, -NH2), 4.40 (q, J = 7.2 Hz, 2H, -CH2CH3), 2.72
13
(s, 3H), 1.41 (t, J = 7.2 Hz, 3H, -CH2CH3). C-NMR (CDCl3) δ: 168.8, 162.5, 151.1, 150.9, 135.4,
131.9, 131.8, 130.2, 129.6, 129.4, 126.9, 103.4, 101.2, 60.3, 27.7, 13.9. MS-ESI (m/z, relative
intensity, %): 334 (5), 333 (32), 331 (M++1) (100). IR (KBr, cm−1) ν: 3,453, 3,338 (NH2), 3,112 (ArH),
2,973, 2,930 (CH2 and CH3), 1,660 (C=O), 1,590, 1,493, 1,457 (C=N and aromatic ring skeleton
vibration), 1,263 (O-CH3).
Ethyl 4-amino-6-methyl-1-(4-nitrophenyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (3o). Yellowish
solid. m.p. 197–199 °C. 1H-NMR (DMSO) δ: 8.62–8.74 (m, 3H, Ar-H and pyrazole H), 8.36–8.41 (m,
2H, Ar-H), 7.84 (br, 2H, -NH2), 4.32 (q, J = 7.2 Hz, 2H, -CH2CH3), 2.67 (s, 3H, -CH3), 1.33 (t,
J = 7.2 Hz, 3H, -CH2CH3). 13C-NMR (DMSO) δ: 167.8, 161.2, 151.0, 150.5, 144.4, 136.3, 124.9,
119.6, 118.9, 105.4, 102.6, 60.6, 29.3, 14.2. MS-ESI (m/z, relative intensity, %): 344 (M++3) (2.5), 343
(M++2) (18), 342 (M++1) (100). IR (KBr, cm−1) ν: 3,453, 3,333 (NH2), 3,112 (ArH), 2,978, 2,930 (CH2
andCH3), 1,678 (C=O), 1,616, 1,545, 1,512 (C=N and aromatic ring skeleton vibration), 1,275 (O-CH3).
Ethyl
4-amino-1-(2,4-dinitrophenyl)-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate
(3p).
Yellowish solid. m.p. 205–206 °C. 1H-NMR (DMSO) δ: 8.86 (s, 1H, Ar-H), 8.69–8.73 (m, 1H, Ar-H),
8.52 (s, 1H, pyrazole H), 8.43 (d, J = 9.0 Hz, 1H, Ar-H), 7.74 (br, 2H, -NH2), 4.39 (q, J = 7.2 Hz, 2H, -