758
A. A. O. Sarhan
1H-Indole-2-carboxylic acid (2-nitro-benzylidene)-hydrazide (3d; C16H12N4O3)
Yield: 76%; m.p.: 231±233ꢀC; IR (KBr): ꢀ 3300s, 3050s, 1660w, 1610s, 1535s, 1510s, 1235s,
1
730s cm
;
1H NMR (DMSO-d6, ꢁ, 90 MHz); 11.8 (s, NHindole, exchangeable), 11.2 (s, CONH,
exchangeable), 8.9 (s, N=CH), 7.0±8.3 (m, 8Harom CHindole) ppm.
1H-Indole-2-carboxylic acid (4-N-dimethyl-benzylidene)-hydrazide (3e; C18H18N4O)
Yield: 72%; m.p.: 218±220ꢀC; IR (KBr): ꢀ 3400s, 3300s, 3050m, 2900w, 1620s, 1590s, 1590s,
1
1560s, 1510s, 1250s, 720s cm
;
1H NMR (TFA, ꢁ, 90 MHz): 8.1 (s, N=CH), 7.0±7.9 (m,
8Harom CHindole), 3.2 (s, 6H, NꢁCH32) ppm.
1H-Indole-2-carboxylic acid (2-methoxy-benzylidene)-hydrazide (3f; C17H15N3O2)
Yield: 67%; m.p.: 243±245ꢀC; IR (KBr): ꢀ 3325m, 3200m, 3050w, 2960w, 1665s, 1630m, 1520s,
1480s, 1255s, 1050s, 730s cm 1; 1H NMR (DMSO-d6, ꢁ, 90 MHz): 11.8 (s, NHindole, exchangeable),
7.5 (s, N=CH), 6.3±7.4 (m, 8Harom CHindole), 3.5 (s, 3H, OCH3) ppm.
3-Acetyl-4-aryl-1,2,3,4-tetrahydro-indolo[2,3-d]pyridazin-1-ones (general procedure)
A mixture of 0.1 g of 3b or 3c was re¯uxed in 10 cm3 acetyl chloride for 3 h. The reaction mixture
was cooled, diluted with 50 cm3 H2O, and neutralized with Na2CO3 solution; the precipitate formed
was collected by ®ltration. The crude product was washed with H2O (3x) and crystallized from
EtOH.
3-Acetyl-4-(4-chloro-phenyl)-1,2,3,4-tetrahydro-indolo[2,3-d]pyridazin-1-one (4a; C18H14N3O2Cl)
Yield: 81%; m.p.: 200±201ꢀC; IR (KBr): ꢀ 3300s, 3210m, 3050w, 2910w, 1700m, 1660s, 1635s,
1
1545m, 1485s, 1250s, 1090s, 810s, 740s cm
;
1H NMR (DMSO-d6, ꢁ, 90 MHz): 6.9±7.8 (m,
8Harom CHpyridazine), 2.4 (s, 3H, COCH3) ppm; MS: m/z (%) 341 [M2] (30), 340 [M1] (24),
339 [M ] (55), 296 (65), 279 (39), 266 (18), 252 (6), 237 (10), 232 (11), 219 (12), 217 (27), 204
(25), 199 (94), 186 (33), 165 (37), 160 (21), 155 (16), 145 (16), 144 (100), 149 (43), 137 (50), 129
(46), 116 (20), 114 (13), 111 (13), 102 (21), 92 (12), 89 (37), 77 (8), 74 (53), 63 (11), 50 (4), 43 (29).
3-Acetyl-4-(4-methoxy-phenyl)-1,2,3,4-tetrahydro-indolo[2,3-d]pyridazin-1-one (4b; C19H17N3O3)
Yield: 76%; m.p.: 151±153ꢀC; IR (KBr): ꢀ 3290s, 3200m, 3050s, 2930w, 2820w, 1700s, 1660m,
1
1600s, 1540m, 1500s, 1245s, 1060s, 830s, 740s cm
;
1H NMR (CDCl3, ꢁ, 90 MHz): 10.1 (s,
NHpyridazinone, exchangeable), 11.1 (s, NHindole, exchangeable), 6.4±7.4 (m, 8Harom CHpyridazine), 3.8
(s, 3H, OCH3), 2.2 (s, 3H, COCH3) ppm.
1H-Indole-2-carboxylic acid N1-acetyl-hydrazide (6; C11H11N3O2)
A sample of 0.4 g 2 (2.2 mmol) was re¯uxed in 10 cm3 acetic acid for 5 h. The reaction mixture was
cooled, and the crystalline product was collected by ®ltration to give 0.35 g (72%) of 6.
M.p.: 273±275ꢀC; IR (KBr): ꢀ 3300s, 3250s, 3050m, 1670s, 1650s, 1540s, 1490s, 1250s, 740s,
1
700s cm
;
1H NMR (DMSO-d6, ꢁ, 90 MHz): 11.9 (s, NHindole, exchangeable), 10.3 (s, NHCO,
exchangeable), 9.9 (s, NHCO, exchangeable), 7.0±7.9 (m, 4Harom CHindole), 2.0 (s, 3H, CH3) ppm;
MS: m/z (%) 217 [M ] (3), 216 (27), 215 (96), 198 (6), 173 (27), 143 (100), 130 (12), 116 (34),
115 (80), 102 (8), 98 (99), 77 (9), 63 (45), 50 (7).