Synthesis and Structure Elucidation
1117
Experimental
The melting points were obtained using an Electrothermal IA 9100 Digital melting point
apparatus. The IR spectra were recorded on a Bruker IFS-88 instrument (the samples as KBr
disks for the range 400-4000 cm-1). The 1H and 13C NMR spectra were recorded on a Bruker
AC-300 spectrometer (1H, 300.134 MHz; 13C, 75.469 MHz) using TMS as internal standard.
Mass spectrometric measurements were made on an Agilent Technologies 6890 N Network
GC system. The C, H, N analyses were performed by the microanalytical service of the
N.I.O.C. Research Institute of Petroleum Industry.
2-Phenyl-4-methoxycarbonylmethylen-1(3H)-imidazol-5-one (2)
A solution of benzimidinium chlorid (1.57 g, 10 mmol) and DMAD (1.42 g, 10 mmol)
in 15 mL of MeOH was heated at reflux for 3 h. The solution was cooled and the
reaction vessel set aside overnight. The crystals formed were separated. Yield 92%, mp
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1
156-157 C; MS: m/z 230 (M+); FT-IR: NH2 3082, CO 1748, 1672 cm-1; H NMR
(DMSO-d6) δ 3.88 (s, 3H, OMe), 7.05 (s, 1H, =CH), 7.58 (m, 3H, Ar-H), 8.08 (m, 2H,
Ar-H), 11.66 (s, 3H, NH). 13C NMR (DMSO-d6) δ 51.7 (OMe), 115.9 (=CH), 126.1 (C-Ar),
128.5 (C-Ar), 129.5 (C-Ar), 132.9 (C-Ar), 151.9 (C=C), 167.5 (C=N), 168.9 (C=O),
187.4 (C=O). Anal. Calcd. for C12H10N2O3: C, 62.61; H, 4.35; N, 12.17. Found: C,
62.59; H, 4.33; N, 12.18.
2-Phenyl-4-hydrazinecarbonylmethylen-1(3H)-imidazol-5-one (3)
A mixture of 2 (2.30 g, 10 mmol) and hydrazine hydrate (0.85 mL, 15 mmol, 85%) in
30 mL of methanol was heated at reflux for 1 h. The methanol, water and excess
hydrazine hydrate were removed in vacuo, and the residual solid recrystallized from
ethanol. Yield 88%, mp > 300 oC; MS: m/z 231 (M+); FT-IR: NH2 3294, CO 1688, 1695 cm-1;
1H NMR (DMSO-d6) δ 4.90 (s, 2H, NH2), 6.79 (s, 1H, =CH), 7.55 (m, 3H, Ar-H), 7.72
(m, 2H, Ar-H), 8.41 (br, 1H, NH), 10.17 (s, 1H, NH). 13C NMR (DMSO-d6) δ 119.5
(=CH), 126.0 (C-Ar), 128.4 (C-Ar), 129.1 (C-Ar), 131.2 (C-Ar), 149.5 (=C), 158.7 (C=N),
162.9 (C=O), 165.3 (C=O). Anal. Calcd. for C11H10N4O2: C, 57.14; H, 4.33; N, 24.24.
Found: C, 57.15; H, 4.31; N, 24.22.
4-(4-Amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-ylmethylen)-2-phenyl-1(3H)-
imidazol-5-one (5)
Carbon disulfide (0.85 mL, 14 mmol) was added drop wise to an ice-cold solution of
potassium hydroxide (0.84 g, 15 mmol) and 3 (2.08 g, 9 mmol) in 30 mL absolute ethanol.
The mixture was stirred at room temperature for 14 h. Dry ether 20 mL was then added and
the separated solid was filtered and washed with ether (2x5 mL). The product 4 obtained in
nearly quantitative yields was employed in the next reaction without further purification. A
suspension of 4 (about 2.75 g, 8 mmol) and hydrazine hydrate ( 0.91 mL, 16 mmol, 85%) in
20 mL of water refluxed while stirring for 4 h. Hydrogen sulfide was evolved. On dilution
with 100 mL of cold water and acidification with concentrated HCl, the solid was
precipitated. The product was filtered, washed with water and recrystallized from ethanol.
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1
Yield 85%, mp 213 C; MS: m/z 286 (M+); FT-IR: NH2 3440, CO 1678 cm-1; H NMR
(DMSO-d6) δ 6.05 (s, 2H, NH2), 7.15 (s, 1H, =CH), 7.64 (m, 3H, Ar-H), 8.20 (m, 2H, Ar-H),
13.07 (br, 1H, NH), 14.24 (s, 1H, NH). 13C NMR (DMSO-d6) δ 121.1 (=CH), 125.7 (C-Ar),
127.6 (C-Ar), 128.3 (C-Ar), 132.1 (C-Ar), 151.3 (=C), 153.2 (C=N), 156.5 (C=N), 166.2
(C=O), 180.2 (C=S). Anal. Calcd. for C12H10N6OS: C, 50.35; H, 3.50; N, 29.37. Found: C,
50.33; H, 3.51; N, 29.35.
Vahedi, Hooshang
