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A. Chandra Shekhar et al. / European Journal of Medicinal Chemistry 77 (2014) 280e287
reaction mixture was stirred at 60 ꢀC for 16e18 h. Progress of the
reaction mixture was monitored by TLC and after completion of
the reaction, the mixture was poured into ice cold water to furnish
pale yellow solid. The solid was filtered, washed with hexane and
further purified through column chromatography.
5H, ArH); 7.44e7.51 (m, 2H, AreH); 7.32e7.42 (m, 7H, ArH); 5.57 (s,
2H, CH2Ph); 4.45 (q, 2H, OeCH2, J ¼ 7.5 Hz); 1.42 (t, 3H, OCH2CH3,
J ¼ 7.5 Hz). ESIeMS (M þ H): 580; Anal. Calcd. for C34H24F3N3O3: C,
70.46; H, 4.17; N, 7.25%. Found: C, 70.43; H, 4.19; N, 7.27%.
4.1.12. Ethyl 7-ethyl-2,3-bis(4-fluorophenyl)-10-oxo-7,10-
dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5g)
4.1.6. Ethyl 7-ethyl-10-oxo-2,3-diphenyl-7,10-dihydropyrido[3,2-f]
quinoxaline-9-carboxylate (5a)
Yellow colored solid; IR (KBr, cmꢂ1): 1731.51 (ester CO) cmꢂ1; 1H
Pale yellow colored solid; IR (KBr, cmꢂ1): 1725.25 (ester CO)
NMR (CDCl3, 300 MHz): d 8.45 (s, 1H, CH attached to N); 8.30 (d, 1H,
cmꢂ1; 1H NMR (TFA þ CDCl3, 300 MHz):
d
9.42 (s, 1H, ArH), 9.00 (d,
AreH, J ¼ 9.8 Hz); 7.84e7.90 (m, 2H, ArH); 7.80 (d, 1H, AreH,
J ¼ 9.8 Hz); 7.60e7.67 (m, 2H, ArH); 7.00e7.13 (m, 4H, ArH); 4.33e
4.55 (m, 4H, OeCH2); 1.63 (t, 3H, OeCH2eCH3, J ¼ 7.5 Hz); 1.42 (t,
3H, OeCH2eCH3, J ¼ 6.7 Hz). ESIeMS (M þ H): 486; Anal. Calcd. for
1H, ArH, J ¼ 9.8 Hz), 8.55 (d, 1H, ArH, J ¼ 9.8 Hz), 7.42e7.90 (m, 10H,
ArH), 4.98 (q, 2H, OCH2, J ¼ 7.3 Hz), 4.60 (q, 2H, NCH2, J ¼ 6.7 Hz),
1.80 (t, 3H, J ¼ 7.3 Hz), 1.50 (t, 3H, J ¼ 6.7 Hz). ESIeMS (M þ H): 450;
Anal. Calcd. for C28H23N3O3: C, 74.82; H, 5.16; N, 9.35%. Found: C,
74.80; H, 5.15; N, 9.34%.
C28H21F2N3O3: C, 69.27; H, 4.36; N, 8.66%. Found: C, 69.28; H, 4.37;
N, 8.67%.
4.1.7. Ethyl 10-oxo-2,3-diphenyl-7-(2,2,2-trifluoroethyl)-7,10-
dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5b)
4.1.13. Ethyl 2,3-bis(4-fluorophenyl)-10-oxo-7-(2,2,2-
trifluoroethyl)-7,10-dihydropyrido[3,2-f] quinoxaline-9-carboxylate
(5h)
Pale yellow colored solid; IR (KBr, cmꢂ1): 1725.25 (ester CO)
cmꢂ1
;
1H NMR (CDCl3, 300 MHz):
d
9.39 (s, 1H, CH attached to N),
Pale yellow colored solid; IR (KBr, cmꢂ1): 1687.92 (ester CO)
8.34 (d, 1H, AreH, J ¼ 6.0 Hz), 8.19 (d, 1H, AreH, J ¼ 6.0 Hz),7.54e
7.64 (m, 4H, AreH), 7.35e7.52 (m, 6H, ArH), 6.75e6.87 (m, 2H,
CH2CF3), 4.51 (q, 2H, OeCH2, J ¼ 6.8 Hz), 1.47 (t, 3H, OeCH2CH3,
J ¼ 6.8 Hz). ESIeMS (M þ H): 504; Anal. Calcd. for C28H20F3N3O3: C,
66.80; H, 4.00; N, 8.35%. Found: C, 66.79; H, 4.10; N, 8.34%.
cmꢂ1; 1H NMR (CDCl3, 300 MHz):
d 8.50 (s, 1H, CH attached to N);
8.08 (d, 1H, AreH, J ¼ 9.06 Hz); 7.82e7.91 (m, 2H, ArH); 7.58e7.66
(m, 2H, ArH); 7.55 (d, 1H, AreH, J ¼ 9.0 Hz); 7.31e7.38 (m, 1H, ArH);
6.93e7.08 (m, 3H, ArH); 5.48 (s, 2H, CH2eCF3); 4.33e4.55 (m, 2H,
OeCH2); 1.42 (t, 3H, OCH2CH3, J ¼ 7.5 Hz). ESIeMS (M þ H): 540;
Anal. Calcd. for C28H18F5N3O3: C, 62.34; H, 3.36; N, 7.79%. Found: C,
62.28; H, 3.37; N, 7.77%.
4.1.8. Ethyl 7-butyl-10-oxo-2,3-diphenyl-7,10-dihydropyrido[3,2-f]
quinoxaline-9-carboxylate (5c)
Pale yellow colored solid; IR: (KBr, cmꢂ1): 1702.27 (ester CO)
4.1.14. Ethyl 7-butyl-2,3-bis(4-fluorophenyl)-10-oxo-7,10-
dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5i)
cmꢂ1; 1H NMR (DMSO-d6, 300 MHz):
d 8.48 (s, 1H, CH attached to
N); 8.25e8.37 (m, 1H, ArH); 7.82 (d, 1H, AreH, J ¼ 7.7 Hz); 7.57e7.68
(m, 3H, ArH); 7.27e7.42 (m, 7H, ArH); 4.45e4.49 (m, 1H, CH); 4.39
(q, 2H, O/NeCH2, J ¼ 6.9 Hz); 4.26 (t, 1H, CH, J ¼ 7.3 Hz); 1.79e2.02
(m, 2H, CH2); 1.37e1.57 (m, 5H, CH2); 1.03 (t, 2H, CH, J ¼ 7.3 Hz);
0.77 (t, 1H, eCH, J ¼ 7.3 Hz). ESIeMS (M þ H): 478; Anal. Calcd. for
for C30H27N3O3: C, 75.45; H, 5.70; N, 8.80%. Found: C, 75.47; H, 5.69;
N, 8.82%.
Pale yellow colored solid; IR (KBr, cmꢂ1): 1712.45 (ester CO)
cmꢂ1; 1H NMR (CDCl3, 300 MHz):
d 9.28 (s, 1H, CH attached to N);
8.45 (s, 1H, AreH); 8.31 (d, 1H, AreH, J ¼ 7.1 Hz); 7.78e7.87 (m, 2H,
ArH); 7.57e7.67 (m, 2H, ArH); 6.95e7.14 (m, 4H, ArH); 4.21e4.54
(m, 4H, O/NeCH2); 1.79e2.04 (m, 2H, CH2); 1.37e1.56 (m, 4H, CH2);
1.20e1.29 (m, 1H, CH); 0.99e1.08 (m, 2H, CH); 0.78 (t, 1H, CH,
J ¼ 7.3 Hz); 13C NMR (CDCl3, 75 MHz):
d 174.2, 165.0, 153.1, 151.5,
150.4, 147.0, 141.5, 140.3, 136.7, 134.5, 133.9, 133.4, 132.7 (d,
J ¼ 8.7 Hz), 131.6 (d, J ¼ 8.7 Hz), 118.9, 115.4 (d, J ¼ 21.9 Hz), 115.2 (d,
J ¼ 21.9 Hz), 61.8, 54.9, 19.8, 18.7, 14.3, 13.6. ESIeMS (M þ H): 514;
Anal. Calcd. for C30H25F2N3O3: C, 70.16; H, 4.91; N, 8.18%. Found: C,
70.17; H, 4.95; N, 8.17%.
4.1.9. Ethyl 10-oxo-2,3-diphenyl-7-(prop-2-ynyl)-7,10-
dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5d)
Pale yellow colored solid; IR (KBr, cmꢂ1): 3040.20 (CCH),
1699.02 (ester CO) cmꢂ1; 1H NMR (CDCl3, 300 MHz):
d 8.63 (s, 1H,
CH attached to N); 8.20 (d, 1H, ArH, J ¼ 8.9 Hz); 7.80e7.90 (m, 2H,
ArH); 7.50e7.65 (m, 5H, ArH); 7.00e7.14 (m, 5H, ArH); 4.91 (d, 2H,
NeCH2, J ¼ 2.4 Hz), 4.42 (q, 4H, NeCH2, J ¼ 7.0 Hz); 2.95 (s, 1H,
CCH); 1.40 (t, 3H, CH3, J ¼ 7.0 Hz). ESIeMS (M þ H): 460; Anal. Calcd.
for C29H21N3O3: C, 75.80; H, 4.61; N, 9.14%. Found: C, 75.79; H, 4.66;
N, 9.17%.
4.1.15. Ethyl 2,3-bis(4-fluorophenyl)-10-oxo-7-(prop-2-ynyl)-7,10-
dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5j)
Pale yellow colored solid; IR (KBr, cmꢂ1): 3010.20 (CCH), 1717.84
(ester CO) cmꢂ1; 1H NMR (CDCl3, 300 MHz):
d 8.46 (s, 1H, CH); 8.30
(d, 1H, AreH, J ¼ 8.8 Hz); 7.80e7.90 (m, 2H, ArH); 7.60e7.67 (m, 2H,
ArH); 6.99e7.13 (m, 5H, ArH); 5.01 (partially split doublet, 2H, Ne
CH2, J ¼ 2.4 Hz); 4.41 (q, 4H, NeCH2, J ¼ 7.2 Hz); 2.95 (s, 1H, CCH);
1.40 (t, 3H, CH3, J ¼ 7.2 Hz). ESIeMS (M þ H): 496; Anal. Calcd. for
4.1.10. Ethyl 7-(4-fluorobenzyl)-10-oxo-2,3-diphenyl-7,10-
dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5e)
Yellow colored solid; IR (KBr, cmꢂ1): 1678.27 (ester CO) cmꢂ1
;
C29H19F2N3O3: C, 70.30; H, 3.87; N, 8.48%. Found: C, 70.29; H, 3.86;
1H NMR (DMSO-d6, 300 MHz):
d
8.65 (s, 1H, CH attached to N); 8.18
N, 8.47%.
(d, 1H, AreH, J ¼ 9.5 Hz); 7.75 (d, 1H, ArH, J ¼ 9.5 Hz); 7.54e7.63 (m,
5H, ArH); 7.29e7.43 (m, 5H, ArH); 7.20e7.25 (m, 2H, ArH); 7.05e
7.10 (m, 2H, ArH); 5.63 (s, 2H, CH2Ph); 4.39 (q, 2H, OeCH2,
J ¼ 6.3 Hz); 1.40 (t, 3H, OeCH2eCH3, J ¼ 6.3 Hz). ESIeMS (M þ H):
530; Anal. Calcd. for C33H24FN3O3: C, 74.85; H, 4.57; N, 7.93%.
Found: C, 74.89; H, 4.55; N, 7.95%.
4.1.16. Ethyl 7-(4-fluorobenzyl)-2,3-bis(4-fluorophenyl)-10-oxo-
7,10-dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5k)
White colored solid; IR (KBr, cmꢂ1): 1678.48 (ester CO) cmꢂ1; 1H
NMR (DMSO-d6, 300 MHz): d 8.65 (s, 1H, CH attached to N); 8.15 (d,
1H, AreH, J ¼ 9.5 Hz); 7.81e7.86 (m, 2H, ArH); 7.75 (d, 1H, AreH,
J ¼ 9.5 Hz); 7.59e7.64 (m, 2H, ArH); 7.35e7.39 (m, 1H, ArH); 7.20e
7.25 (m, 2H, ArH); 7.01e7.11 (m, 4H, ArH); 6.98 (t, 1H, ArH,
J ¼ 8.7 Hz); 5.62 (s, 2H, CH2Ph); 4.40 (q, 2H, OeCH2, J ¼ 6.9 Hz); 1.40
(t, 3H, OeCH2eCH3, J ¼ 6.9 Hz). ESIeMS (M þ H): 566.4; Anal. Calcd.
for C33H22F3N3O3: C, 70.08; H, 3.92; N, 7.43%. Found: C, 70.09; H,
3.95; N, 7.45%.
4.1.11. Ethyl 7-(4-(trifluoromethyl)benzyl)-10-oxo-2,3-diphenyl-
7,10-dihydropyrido[3,2-f]quinoxaline-9-carboxylate (5f)
Pale yellow colored solid; IR (KBr, cmꢂ1): 1698.24 (ester CO)
cmꢂ1
;
1H NMR (CDCl3, 300 MHz):
d
8.51 (s, 1H, CH attached to N);
8.13 (d,1H, AreH, J ¼ 9.8 Hz); 7.85e7.92 (m, 2H, ArH); 7.60e7.69 (m,