794
J Fluoresc (2010) 20:787–796
124.9, 125.2, 127.2, 127.9 (2 C’s), 128.7 (2 C’s), 129.6 (2
C’s), 133.4, 133.5, 139.1, 144.4, 148.5, 149.9. MS (70 eV) m/z
(%): 339 (100) [M+], 262 (29), 248 (25), 119 (17), 105 (21),
91 (23), 77 (38). Anal. Calcd. for C21H17N5 (339.40): C,
74.32; H, 5.05; N, 20.63. Found: C, 74.44; H, 4.94; N, 20.52.
(66.87%), recrystallized from ethanol to afford colorless
solid; mp 247–248 °C. IR (KBr): 3,278 m, 3,061 m,
2,939 m, 1,659 m, 1,590 m, 1,507 s, 1,428 m, 1,247 m,
818w cm−1. 1H NMR (300 MHz, DMSO-d6) δ: 2.91 (s, 3H,
CH3), 5.26 (s, 2H, CH2), 7.02 (t, J=8.4 Hz, 2H, Ar–H),
7.34 (t, J=7.8 Hz, 1H, Ar–H), 7.44 (m, 2H, Ar–H), 7.53 (t,
J=7.8 Hz, 2H, Ar–H), 8.14 (d, J=7.8 Hz, 2H, Ar–H), 8.35
(s, 1H, Ar–H), 9.06 (s, 1H, Ar–H), 9.14 (s, 1H, NH). 13C
NMR (75 MHz, DMSO-d6): 14.0, 55.8, 103.5, 115.4,
115.7, 115.9, 121.1 (2 C’s), 121.3, 125.8, 129.0 (2 C’s),
130.6, 134.9, 139.4, 141.3, 144.2, 147.5, 148.2, 151.2,
153.5, 164.5. MS (70 eV) m/z (%): 400 (100) [M+], 309
(18), 290 (41), 262 (26), 95 (20), 91 (23), 77 (34). Anal.
Calcd. for C22H17FN6O (400.42): C, 65.99; H, 4.28; N,
20.99. Found: C, 66.14; H, 4.17; N, 21.09.
General procedure for the synthesis of (8a–f) A solution of
4e (0.1 g, 0.40 mmol), 7a–f (0.44 mmol) and anhydrous
potassium carbonate (0.066 g, 0.48 mmol) in dimethyl
formamide (3 mL) was heated at 55–60 °C for 6 h. The
reaction mass was cooled at room temperature, ice cold
water (1 mL) was added into the reaction mass, the solid
obtained was filtered, dried and recrystallized to afford 8 in
good yield.
2-(8-methyl-6-phenyldipyrazolo[3,4-b:3′,4′-d]pyridin-1
(6H)-yl)-N-phenylacetamide (8a) Yield: 0.102 g (66.66%),
recrystallized from ethanol to afford colorless solid; mp
239–240 °C. IR (KBr): 3,263 m, 3,036 m, 2,923 m,
1,665 m, 1,601 m, 1,508 s, 1,429 m, 1,234 m, 753w cm−1.
1H NMR (300 MHz, DMSO-d6) δ: 2.74 (s, 3H, CH3), 5.41
(s, 2H, CH2), 7.24–7.31 (m, 6H, Ar–H), 7.43–7.50 (m, 4H,
Ar–H), 8.65 (s, 1H, Ar–H), 9.06 (s, 1H, Ar–H), 10.67 (s,
1H, NH). 13C NMR (75 MHz, DMSO-d6) δ: 14.8, 56.1,
109.9, 115.5, 120.6 (2 C’s), 121.1 (2 C’s), 123.9, 124.5,
125.9, 128.7 (2 C’s), 129.6 (2 C’s), 135.8, 137.9, 139.5,
143.5, 148.2, 149.1, 165.4. MS (70 eV) m/z (%): 382 (100)
[M+], 290 (41), 262 (26), 248 (23), 148 (16), 134 (22), 91
(17), 77 (33). Anal. Calcd. for C22H18N6O (382.43): C,
69.10; H, 4.74; N, 21.98. Found: C, 69.28; H, 4.82; N,
22.19.
N-(4-chlorophenyl)-2-(8-methyl-6-phenyldipyrazolo[3,4-
b:3′,4′-d]pyridin-1(6H)yl)acetamide (8d) Yield: 0.111 g
(66.46%), recrystallized from ethanol to afford colorless
solid; mp 241–242 °C. IR (KBr): 3,314 m, 3,064 m,
2,935 m, 1,666 m, 1,595 m, 1,500 s, 1,454 m, 1,230 m,
760w cm−1. 1H NMR (300 MHz, DMSO-d6) δ: 2.71 (s, 3H,
CH3), 5.48 (s, 2H, CH2), 7.32–7.39 (m, 3H, Ar–H), 7.53–
7.64 (m, 4H, Ar–H), 8.21 (d, J=7.4 Hz, 2H, Ar–H), 8.87 (s,
1H, Ar–H), 9.13 (s, 1H, Ar–H), 10.70 (s, 1H, NH). 13C
NMR (75 MHz, DMSO-d6) δ: 14.1, 55.6, 108.5, 115.9,
120.6 (2 C’s), 121.3 (2 C’s), 125.8, 127.4, 128.9 (2 C’s),
129.0 (2 C’s), 130.6, 134.6, 137.4, 139.4, 144.2, 148.2,
152.3, 169.7. MS (70 eV) m/z (%): 418 (33) [M+2], 416
(100) [M+], 290 (27), 248 (21), 126 (20), 91 (25), 77 (32).
Anal. Calcd. for C22H17ClN6O (416.87): C, 63.39; H, 4.11;
N, 20.16. Found: C, 63.23; H, 4.03; N, 20.07.
2-(8-methyl-6-phenyldipyrazolo[3,4-b:3′,4′-d]pyridin-1
(6H)-yl)-N-p-tolylacetamide (8b) Yield: 0.107 g (67.29%),
recrystallized from ethanol to afford colorless solid; mp
251–252 °C. IR (KBr): 3,289 m, 3,048 m, 2,915 m,
1,673 m, 1,594 m, 1,505 s, 1,432 m, 1,226 m, 758w cm−1.
1H NMR (300 MHz, DMSO-d6) δ: 2.24 (s, 3H, CH3), 2.71
(s, 3H, CH3), 5.44 (s, 2H, CH2), 7.12 (d, J=8.2 Hz, 2H,
Ar–H), 7.32 (t, J=7.8 Hz, 1H, Ar–H), 7.48 (d, J=8.2 Hz,
2H, Ar–H), 7.54 (t, J=7.8 Hz, 2H, Ar–H), 8.22 (d, J=
7.8 Hz, 2H, Ar–H), 8.87 (s, 1H, Ar–H), 9.14 (s, 1H, Ar–H),
10.65 (s, 1H, NH). 13C NMR (75 MHz, DMSO-d6) δ: 14.5,
23.2, 55.4, 108.8, 115.1, 120.8 (2 C’s), 121.6 (2 C’s),
124.2, 125.1, 128.9 (2 C’s), 129.5 (2 C’s), 133.6, 134.7,
135.1, 138.6, 143.9, 147.7, 150.6, 164.8. MS (70 eV) m/z
(%): 396 (100) [M+], 305 (16), 290 (34), 262 (19), 248
(23), 134 (25), 106 (19), 91 (26), 77 (37). Anal. Calcd. for
C23H20N6O (396.46): C, 69.68; H, 5.08; N, 21.20. Found:
C, 69.86; H, 4.99; N, 21.06.
N-(2-chloro-6-fluorophenyl)-2-(8-methyl-6-phenyldipyra-
zolo[3,4-b:3′,4′-d]pyridin-1(6H)-yl) acetamide (8e) Yield:
0.114 g (65.51%), recrystallized from ethanol to afford
colorless solid; mp 268–269 °C. IR (KBr): 3,279 m, 3,027 m,
2,941 m, 1,654 m, 1,598 m, 1,503 s, 1,431 m, 1,246 m, 783w
cm−1. 1H NMR (300 MHz, DMSO-d6) δ: 2.69 (s, 3H, CH3),
5.56 (s, 2H, CH2), 7.31–7.40 (m, 4H, Ar–H), 7.53 (t, J=
7.4 Hz, 2H, Ar–H), 8.22 (d, J=7.4 Hz, 2H, Ar–H), 8.89 (s,
1H, Ar–H), 9.10 (s, 1H, Ar–H), 10.31 (s, 1H, NH). 13C
NMR (75 MHz, DMSO-d6) δ: 14.1, 55.0, 103.5, 114.9,
115.9, 121.3 (2 C’s), 125.4, 125.8, 126.9, 129.0 (2 C’s),
130.5, 132.1, 139.4, 141.4, 143.9, 146.8, 148.2, 150.6,
154.1, 165.0. MS (70 eV) m/z (%): 436 (35) [M+2], 434
(100) [M+], 343 (21), 248 (28), 144 (26), 105 (16), 77 (29).
Anal. Calcd. for C22H16ClFN6O (434.86): C, 60.77; H,
3.71; N, 19.33. Found: C, 60.98; H, 3.81; N, 19.21.
N-(2,4-dichlorophenyl)-2-(8-methyl-6-phenyldipyrazolo
[3,4-b:3′,4′-d]pyridin1(6H)yl) acetamide (8f) Yield: 0.12 g
(66.29%), recrystallized from ethanol to afford colorless
N-(4-fluorophenyl)-2-(8-methyl-6-phenyldipyrazolo[3,4-
b:3′,4′-d]pyridin-1(6H)yl)acetamide (8c) Yield: 0.107 g