1088
B. F. Abdel-Wahab et al.
and neutralized with 2 N NaOH. The formed solid was filtered
off, dried, and crystallized to give 0.25 g (77%) 7. Mp >300ꢁC
(EtOH); IR (film): ꢂꢀ¼ 3260–3210 (NH), 1684 (C¼O), 1660
D2O); MS (EI, 70eV): m=z (%) ¼ 386 [Mþ þ 3, 4] and at
309 [100, base peak].
(C¼N) cmꢂ1
;
1H NMR (DMSO-d6): ꢃ ¼ 4.27 (s, NH–Ph,
2-(2-(p-Bromophenyl)hydrazono)-N1-(1H-benzo[d]imidazol-
2-yl)-N3-(thiazol-2-yl)malonamide (9, C19H14BrN7O2S)
A mixture of 0.38g 8c (1mmol) and 0.133 g 2-aminobenzi-
midazole (1mmol) in 20cm3 absolute ethanol in the presence
of 0.03g sodium ethoxide (1.5 mmol) was refluxed for 2 h.
The reaction mixture was cooled, then poured into ice-water,
and acidified with diluted HCl to pH ꢅ6. The formed solid
was filtered off, dried, and crystallized to give 0.26g (55%)
9. Mp 261–263ꢁC (EtOH); IR (film): ꢂꢀ¼ 3244–3188 (NH),
1678, 1658 (C¼O), 1654 (C¼N) cmꢂ1; 1H NMR (DMSO-d6):
ꢃ ¼ 6.99 (s, NH-imidazole, exchangeable with D2O), 7.22,
7.25 (2d, thiazole-H), 7.38–7.58 (m, Ar–H), 11.40 (s, NH,
exchangeable with D2O), 12.31 (s, NH, exchangeable with
D2O), 12.73 (s, NH, exchangeable with D2O) ppm; MS (EI,
70eV): m=z (%) ¼ 484 [Mþ, 5] and at 140 [100, base peak].
exchangeable with D2O), 4.15 (s, CH2), 7.16, 7.26 (2d, thia-
zole-H), 7.28–7.58 (m, Ar–H); 11.19 (s, NH, exchangeable
with D2O) ppm; MS (EI, 70eV): m=z (%) ¼ 317 [Mþ, 52] and
at 142 [100, base peak].
Synthesis of methyl 2-(2-arylhydrazono)-2-(thiazol-2-yl-
carbamoyl)acetates 8a–8d
To a mixture of 0.2 g 1 (1mmol) and 0.5g sodium acetate
trihydrate (20 mmol) in 25cm3 ice-cold ethanol (ꢂ5ꢁC), the
appropriate aryl diazonium salts of aniline, 4-chloroaniline, 4-
bromoaniline or 4-aminobenzenesulfonamide (1mmol) were
added drop-wise with stirring. The reaction mixture was stir-
red in an ice bath for 2 h, the formed solid was filtered off,
dried, and crystallized to give 0.22 g (74%) 8a, 0.25g (76%)
8b, 0.28 g (75%) 8c, and 0.24 g (62%) 8d.
3-Hydroxy-2-{[4-(4,5,6,7-tetrachloro-1,3-dioxo-1,3-dihydro-
isoindole-2-sulfonyl)phenyl]hydrazono}-3-(thiazol-2-
Methyl 2-(2-phenylhydrazono)-2-(thiazol-2-ylcarbamoyl)-
acetate (8a, C13H12N4O3S)
ylamino)propionic acid methyl ester (10, C21H11Cl4N5O7S2)
A mixture of 0.38 g 8d (1mmol) and 0.29g of 3,4,5,6-tetra-
chlorophthalic anhydride (1mmol) in 50 cm3 glacial acetic
acid was heated under reflux for 6 h. The reaction mixture
was evaporated under reduced pressure, the obtained residue
was solidified with ether, filtered off, and crystallized to yield
0.5 g (77%) 10. Mp 246–248ꢁC (AcOH=H2O); IR (film):
ꢂꢀ¼ 3266–3238 (NH), 1785 (2C¼O), 1733 (C¼O, ester),
Mp 147–149ꢁC (EtOH=H2O); IR (film): ꢂꢀ¼ 3244–3235
(NH), 1735 (C¼O, ester), 1682 (C¼O, amide), 1657 (C¼N)
cmꢂ1; 1H NMR (DMSO-d6): ꢃ ¼ 3.36 (s, CH3), 7.12, 7.19 (2d,
thiazole-H), 7.28–7.59 (m, Ar–H), 12.24 (s, NH, exchange-
able with D2O), 13.28 (s, NH, exchangeable with D2O) ppm;
MS (EI, 70 eV): m=z (%) ¼ 303 [Mþ-1, 2] and at 123 [100,
base peak].
1
1675 (C¼O, amide), 1654 (C¼N), 1330 (S¼O) cmꢂ1; H
NMR (DMSO-d6): ꢃ ¼ 3.36 (s, CH3), 7.11, 7.24 (2d, thia-
zole-H), 7.55 (d, Ar–H), 7.85 (d, Ar–H), 11.85 (s, NH, ex-
changeable with D2O), 12.22 (s, NH, exchangeable with D2O)
ppm; MS (EI, 70eV): m=z (%) ¼ 651 [Mþ, 15] and at 83 [100,
base peak].
Methyl 2-(2-(p-chlorophenyl)hydrazono)-2-(thiazol-2-yl-
carbamoyl)acetate (8b, C13H11ClN4O3S)
Mp 158–160ꢁC (EtOH=H2O); IR (film): ꢂꢀ¼ 3256–3245
(NH), 1733 (C¼O, ester), 1684 (C¼O, amide), 1654 (C¼N)
cmꢂ1; 1H NMR (DMSO-d6): ꢃ ¼ 3.34 (s, CH3), 7.11, 7.23 (2d,
thiazole-H), 7.51 (d, Ar–H), 7.69 (d, Ar–H), 11.92 (s, NH,
exchangeable with D2O), 12.73 (s, NH, exchangeable with
D2O) ppm; MS (EI, 70 eV): m=z (%) ¼ 338 [Mþ, 68] and at
307 [100, base peak].
2,5-Dihydro-5-oxo-1-aryl-N-(thiazol-2-yl)-1H-1,2,3-triazole-
4-carboxamides 11a–11c
A mixture of 8a–8c (2mmol) and 0.8cm3 hydrazine hydrate
(16 mmol) in 30cm3 absolute ethanol was refluxed for 3 h.
The obtained solid was filtered off, dried, and crystallized
from DMF=Ela to afford 0.45 g (78%) 11a, 0.52g (81%)
11b, and 0.58 g (79%) 11c.
Methyl 2-(2-(p-bromophenyl)hydrazono)-2-(thiazol-2-yl-
carbamoyl)acetate (8c, C13H11BrN4O3S)
Mp 154–155ꢁC (EtOH=H2O); IR (film): ꢂꢀ¼ 3262–3255
(NH), 1736 (C¼O, ester), 1680 (C¼O, amide), 1652 (C¼N)
cmꢂ1; 1H NMR (DMSO-d6): ꢃ ¼ 3.37 (s, CH3), 7.14, 7.25 (2d,
thiazole-H), 7.52 (d, Ar–H), 7.71 (d, Ar–H), 11.91 (s, NH,
exchangeable with D2O), 12.70 (s, NH, exchangeable with
D2O) ppm; MS (EI, 70eV): m=z (%) ¼ 384 [Mþ þ 1, 25]
and at 127 [100, base peak].
2,5-Dihydro-5-oxo-1-phenyl-N-(thiazol-2-yl)-1H-1,2,3-
triazole-4-carboxamide (11a, C12H9N5O2S)
Mp 200–201ꢁC (DMF=EtOH); IR (film): ꢂꢀ¼ 3273–3266
(NH), 1678, 1674 (2C¼O), 1657 (C¼N) cmꢂ1
;
1H NMR
(DMSO-d6): ꢃ ¼ 7.23, 7.28 (2d, thiazole-H), 7.24–7.56 (m,
Ar–H), 13.50 (s, NH, exchangeable with D2O), 13.88 (s, NH,
exchangeable with D2O) ppm; MS (EI, 70 eV): m=z (%) ¼ 287
[Mþ, 4] and at 273 [100, base peak].
Methyl 2-(2-(p-sulphonamidophenyl)hydrazono)-2-(thiazol-
2-ylcarbamoyl)acetate (8d, C13H13N5O5S2)
Mp 166–167ꢁC (EtOH=H2O); IR (film): ꢂꢀ¼ 3366–3210 (NH,
NH2), 1734 (C¼O, ester), 1683 (C¼O, amide), 1654 (C¼N)
cmꢂ1; 1H NMR (DMSO-d6): ꢃ ¼ 3.35 (s, CH3), 7.13, 7.26 (2d,
thiazole-H), 7.58 (d, Ar–H), 7.78 (d, Ar–H), 11.96 (s, NH,
exchangeable with D2O), 12.71 (s, NH, exchangeable with
1-(4-Chlorophenyl)-2,5-dihydro-5-oxo-N-(thiazol-2-yl)-1H-
1,2,3-triazole-4-carboxamide (11b, C12H8ClN5O2S)
Mp 216–217ꢁC (DMF=EtOH); IR (film): ꢂꢀ¼ 3278–3255
(NH), 1672, 1667 (2C¼O), 1660 (C¼N) cmꢂ1
;
1H NMR