Molecules 2002, 7
914
1123, 976, 838 cm-1; MS m/z 384 (M+, 13%), 340 (100), 294 (57), 269 (16), 248 (40), 230 (16), 220
(16), 158 (39), 144 (13), 118 (21), 117 (20), 107 (16), 91 (67), 78 (16), 65 (20), 44 (33).
Ethyl 3-(4-methoxyphenyl)amino-2-(5-nitropyrid-2-yl)-5-oxo-2,5-dihydroisoxazole-4-carboxylate (9c).
Yellow needles (80%), m.p.= 186-188 ºC; R (CH2Cl2): 0.68; Analysis: found C, 54.10, H, 3.78, N,
f
1
d
14.11%; C18H16N4O7 requires C, 54.00, H, 4.00, N, 14.00%; H-NMR: = 1.30 (t, J=7Hz, 3H), 3.77 (s,
3H), 4.26 (q, J=7Hz, 2H), 6.79 (d, J=8.7Hz, 2H), 7.10 (d, J=8.7Hz, 2H), 7.52 ( d, J=9.0Hz,1H),
13
d
8.54(dd, J =9 Hz, J =2.1Hz, 1H), 8.93 (bd, J=2.1, 1H), 10.26 (s,1H, NH); C-NMR: = 14.72, 55.89,
1
2
61.36, 78.87, 114.85, 115.59, 124.34, 130.74, 134.68, 141.93, 143.95, 154.33, 158.40, 161.38, 163.69,
164.32; IR v= 3823, 1785, 1700, 1592, 1345, 1207, 1115, 1030, 838 cm-1; MS m/z: 400 (M+, 10%),
356 (100), 310 (49), 295 (43), 264 (21), 249 (13), 221 (14), 193 (12), 194 (10), 174 (21), 146 (10), 134
(34), 133 (22), 123 (17), 92 (16), 77 (29), 44 (37).
Butyl 3-(4-methylphenyl)amino-2-(5-nitropyrid-2-yl)-5-oxo-2,5-dihydroisoxazole-4-carboxylate(10).
Ethyl 3-(4-methylphenyl)amino-5-oxo-2,5-dihydroisoxazole-4-carboxylate (100 mg, 0.30 mmol), and
2-chloro-5-nitropyridine (48.5 mg, 0.30 mmol) were refluxed in 1-butanol (5 mL), for 12 hours. On
cooling, the product was collected and washed with cold ethanol to give the title compound as bright
pale needles (126 mg, 80 %), m.p.=176 ºC; R (CH2Cl2): 0.26; Analysis: found C, 57.41, H, 4.62, N,
f
1
d
13.66%; C20H20N4O6 requires C, 58.25, H, 4.85, N, 13.59%; H-NMR: = 0.96 (t, J=7.5Hz, 3H), 1.42
(sx, J=7.5Hz, 2H), 1.65 (qn, J=7.1Hz, 2H), 2.30 (s, 3H), 4.20 (t, J=6.7Hz, 2H), 7.04 (d, J=8.3Hz, 2H),
7.07 (d, J=8.3Hz, 2H), 7.54 ( d, 9.1 Hz, 1H), 8.55 (dd, J1=9.1 Hz, J2=1.8 Hz, 1H), 8.91 (bd, J=1.8 Hz,
13
d
1H), 10.32 (s,1H, NH); C-NMR: = 14.12, 19.43, 21.33, 30.99, 65.07, 79.03, 115.39, 122.39, 130.27,
134.7, 135.35, 136.74, 141.86, 143.92, 154.28, 160.74, 163.52, 164.15; IR v= 3446, 2831, 1792, 1700,
-1
1600, 1515, 1345, 1123, 846 cm ; MS m/z : 412 (M+, 7%), 368 (100), 340(13) ,338(18) ,312(12)
,294(65) ,269 (22), 248 (32), 220 (15), 158 (24), 144 (12), 118 (20), 107 (18), 91 (44), 78 (10), 77 (12),
57 (17), 44 (38).
Ethyl 2-(4-bromophenyl)amino-6-nitroimidazo[1,2-a] pyridine-3-carboxylate (11a).
The isoxazolone 9a (100 mg, 0.23 mmol) and triethylamine (0.2 mL) were refluxed in ethanol (10 mL)
for 1 h. The mixture was left to cool to room temperature and the desired compound was collected as
1
d
pale cream needles (75.76 mg, 84 %), m.p.= 195 ºC; R (CH2Cl2): 0.72; H-NMR: = 1.57 (t, J=7.1Hz,
f
3H), 4.59(q, J=7.1Hz, 2H), 7.48 (d, J=8.7Hz, 2H), 7.56 (d, J=9.7Hz, 1H), 7.65 (bd, J=8.7Hz, 2H),
d
8.19(dd, J =9.7Hz, J =1.3 Hz, collapsed to doublet, J=8.7Hz, by irradiation at =9.87, 1H), 8.97 (bs,
1
2
1
d
1H, NH), 9.87 (bd, J=1.3Hz, 1H); H-NMR (d6-DMSO): = 1.44 (t, J=7Hz, 3H), 4.46 (q, J=7Hz, 2H),
7.49 (d, J=8.5Hz), 7.68 (d, J=9.7Hz, 1H), 7.74 (d, J=8.5Hz , 2H), 8.19 (dd, J1=9.7Hz, J =1.6Hz, 1H),
2
13
d
8.87 (bd, J=1.6, 1H), 9.88 (s,1H, NH); C-NMR (d6-DMSO): = 15.25, 61.57, 99.72, 114.62, 114.97,
121.76, 123.93, 127.61, 132.38, 137.66, 140.01, 147.17, 155.28, 160.87; IR v =3285, 2955, 1643,