1006
M. Mojzych, A. Rykowski
Vol 44
NH 3250 cm-1; ms: m/z 293 (M+, 100), 250 (15), 194 (12), 192 (35),
111 (58), 99 (27); Anal. Calcd. for C12H12ClN5S: C, 49.06; H, 4.12;
N, 23.84. Found: C, 49.05; H, 4.29; N, 23.64.
mL) p-toluenosulfonic acid (172 mg, 1mmol) was added. The
resulting mixture was heated under reflux until the starting
material disappeared (15-17 hours) as monitored by tlc. Then the
organic solvent was removed in vacuo, and the residue was
purified by column chromatography using CHCl3/MeOH (35:1).
Phenylhydrazone of 5-acetyl-3-methoxy-1,2,4-triazine (1m).
This compound was obtained in a 25% yield; mp. 199-200 °C;
1H nmr (CDCl3): ꢀ 2.32 (s, 3H, CH3), 4.21 (s, 3H, OCH3), 7.01-
7.08 (m, 1H, phenyl), 7.24-7.29 (m, 2H, phenyl), 7.33-7.41 (m,
2H, phenyl), 8.11 (bs, 1H, NH), 9.68 (s, 1H, triazine CH); ir
(KBr): NH 3230 cm-1; Anal. Calcd. for C12H13N5O: C, 59.25; H,
5.39; N, 28.79. Found: C, 59.15; H, 5.43; N, 28.70.
3-Chlorophenylhydrazone of 5-acetyl-3-methylsulfanyl-
1,2,4-triazine (1f). This compound was obtained in a 92% yield;
mp 244-245 °C; 1H nmr (DMSO-d6): ꢀ 2.31 (s, 3H, CH3), 2.70
(s, 3H, SCH3), 6.98-7.12 (m, 2H, phenyl), 7.28-7.32 (m, 2H,
phenyl), 8.00 (s, 1H, NH), 9.63 (s, 1H, triazine CH); ir (KBr):
NH 3220 cm-1; ms: m/z 293 (M+, 10), 219 (33), 218 (24), 217
(100), 182 (25), 155 (23), 111 (52); Anal. Calcd. for
C12H12ClN5S: C, 49.06; H, 4.12; N, 23.84. Found: C, 49.10; H,
4.19; N, 23.69.
Phenylhydrazone of 5-acetyl-3-ethoxy-1,2,4-triazine (1n).
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This compound was obtained in a 22% yield; mp. 215 °C; H
2,4-Dichlorophenylhydrazone of 5-acetyl-3-methylsulfanyl-
1,2,4-triazine (1g). This compound was obtained in a 75%
yield; mp 206-207 °C; H nmr (CDCl3): ꢀ 2.35 (s, 3H, CH3),
2.70 (s, 3H, SCH3), 7.28-7.38 (m, 2H, phenyl), 7.60-7.65 (m,
1H, phenyl), 8.37 (s, 1H, NH), 9.61 (s, 1H, triazine CH); ir
(KBr): NH 3340cm-1; ms: m/z 327 (M+, 100), 228 (18), 226
(25), 175 (18), 173 (28), 162 (29), 160 (45), 147 (30), 145 (46),
135 (18), 133 (28); hrms: (m/z) for C12H1135Cl2N5S: 327.01026
(M+); Calcd. 327.01122.
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nmr (CDCl3): ꢀ 1.52 (t, 3H, J = 7.1 Hz, CH3), 2.31 (s, 3H, CH3),
4.64 (q, 2H, J = 7.1 Hz, CH2), 6.99-7.08 (m, 1H, phenyl), 7.23-
7.29 (m, 2H, phenyl), 7.32-7.41 (m, 2H, phenyl), 8.40 (s, 1H,
NH), 9.66 (s, 1H, triazine CH); ir (KBr): NH 3230 cm-1; Anal.
Calcd. for C13H15N5O: C, 60.70; H, 5.83; N, 27.23. Found: C,
60.71; H, 5.94; N, 27.17.
Preparation of 1H-pyrazolo[4,3-e][1,2,4]triazines (3a-l) in
dry media (Method A). A mixture of 1 (1 mmole) and p-
toluenosulfonic acid (2 mmoles) was heated at about 10 °C over
the melting point of the starting phenylhydrazone for 1 minute.
After cooling, the solid residue was treated with chloroform and
then the major product was isolated by chromatography on silica
gel eluting with chloroform and crystallized from aqueous
ethanol to yield the corresponding pyrazolotriazine 3a-l.
3-Methyl-5-methylsulfanyl-1-phenyl-1H-pyrazolo[4,3-e]-
[1,2,4]triazine (3a). This compound was obtained in a 56%
yield; mp 105 °C. 1H nmr (CDCl3): ꢀ 2.73 (s, 3H, SCH3), 2.77 (s,
3H, CH3), 7.29-7.40 (m, 1H, phenyl), 7.50-7.61 (m, 2H, phenyl),
8.31-8.38 (m, 2H, phenyl); ms: m/z 257 (M+, 43), 216 (22) , 93
(41), 77 (100); Anal. Calcd. for C12H11N5S: C, 56.03; H, 4.28;
N, 27.23. Found: C, 55.67; H, 4.13; N, 27.05.
1-(4-Methoxyphenyl)-3-methyl-5-methylsulfanyl-1H-pyra-
zolo[4,3-e][1,2,4]-triazine (3b). This compound was obtained in
a 49% yield; mp 168 °C; 1H nmr (CDCl3): ꢀ 2.73 (s, 3H, SCH3),
2.77 (s, 3H, CH3), 3.84 (s, 3H, OCH3), 7.30-7.36 (m, 2H,
phenyl), 8.15-8.20 (m, 2H, phenyl); ms: m/z 287 (M+, 70), 258
(20) , 226 (43), 159 (38), 126 (50), 70 (100); Anal. Calcd. for
C13H13N5OS: C, 54.34; H, 4.56; N, 24.37. Found: C, 54.30; H,
4.61; N, 24.27.
4-Nitrophenylhydrazone of 5-acetyl-3-methylsulfanyl-1,2,4-
triazine (1h). This compound was obtained in a 68% yield; mp
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260-263 °C; H nmr (DMSO-d6): ꢀ 2.39 (s, 3H, CH3), 2.72 (s,
3H, SCH3), 7.30-7.35 (m, 2H, phenyl), 8.26-8.30 (m, 3H,
NH+2HAr), 9.64 (s, 1H, triazine CH); ir (KBr): NH 3200 cm–1;
hrms (m/z) for C12H12N6O2S: 304.07344 [M+]; Calcd.
304.07425.
4-Nitrophenylhydrazone of 3-metylosulfanyl-5-propan-oyl-
1,2,4-triazine (1i). This compound was obtained in a 80% yield;
mp 236-237 °C; 1H-NMR (DMSO-d6): ꢀ 1.24 (t, 3H, J = 7.7 Hz,
CH3), 2.71 (s, 3H, SCH3), 2.92 (q, 2H, J = 7.7 Hz, CH2), 7.30-
7.33 (m, 2H, phenyl), 8.26-8.30 (m, 2H, phenyl), 8.42 (s, 1H,
NH), 9.61 (s, 1H, triazine CH); ir (KBr): NH 3220 cm-1; hrms
(m/z) for C13H14N6O2S: 318.08906 (M+); Calcd. 318.08990.
4-Nitrophenylhydrazone of 5-butanoyl-3-metylosulfanyl-
1,2,4-triazine (1j). This compound was obtained in a 83% yield;
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mp 217-218 °C; H nmr (CDCl3): ꢀ 1.07 (t, 3H, J = 7.4 Hz,
CH3), 1.66-1.73 (m, 2H, CH2), 2.70 (s, 1H, SCH3), 2.88 (t, 2H, J
= 7.4 Hz, CH2), 7.29-7.36 (m, 2H, phenyl), 8.04-8.09 (m, 3H,
NH+2HAr), 9.62 (s, 1H, triazine CH); ir (KBr): NH 3250 cm-1;
hrms (m/z) for C14H16N6O2S: 332.10469 (M+); Calcd. 332.10555.
4-Nitrophenylhydrazone of 5-acetyl-3-phenyl-1,2,4-
triazine (1k). This compound was obtained in a 80% yield; mp
237-238 °C; 1H nmr (CDCl3): ꢀ 2.44 (s, 3H, CH3), 7.18-7.25 (m,
2H, phenyl), 7.30-7.37 (m, 2H, phenyl), 7.53-7.59 (m, 3H,
phenyl), 8.02 (s, 1H, NH), 8.55-8.62 (m, 2H, phenyl), 9.83 (s,
1H, triazine CH); ir (KBr): NH 3290 cm-1; hrms (m/z) for
C17H14N6O2: 334.11687 (M+); Calcd. 334.11782.
2-Chlorophenylhydrazone of 5-acetyl-3-phenyl-1,2,4-
triazine (1l). This compound was obtained in a 90% yield; mp
212-213 °C; 1H nmr (CDCl3): ꢀ 2.49 (s, 3H, CH3), 6.92-7.01 (m,
1H, phenyl), 7.31-7.38 (m, 2H, phenyl), 7.52-7.59 (m, 3H,
phenyl), 7.71-7.76 (m, 1H, phenyl), 8.47 (s, 1H, NH), 8.56-8.62
(m, 2H, phenyl), 9.86 (s, 1H, triazine CH); ir (KBr): NH 3330
(NH) cm-1; ms: m/z 323 (M+, 96), 165 (27), 139 (43), 111 (100);
hrms (m/z) for C17H14N5 35Cl: 323.09399 (M+); Calcd.
323.09378. Anal. Calcd. for C17H14ClN5: C, 63.06; H, 4.33; N,
21.64. Found: C, 63.13; H, 4.22; N, 21.64.
3-Methyl-1-(2-methylphenyl)-5-phenyl-1H-pyrazolo[4,3-e]-
[1,2,4]triazine (3c). This compound was obtained in a 63%
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yield; mp 162-163 °C; H nmr (CDCl3): ꢀ 2.29 (s, 3H, CH3),
2.83 (s, 3H, SCH3), 7.37-7.48 (m, 3H, phenyl), 7.50-7.60 (m,
4H, phenyl), 8.62-8.68 (m, 2H, phenyl); hrms (m/z) for
C18H15N5: 301.13617 (M+); Calcd. 301.13275. Anal. Calcd. for
C18H15N5: C, 71.76; H, 5.02; N, 23.25. Found: C, 71.77; H,
4.78; N, 22.94.
3-Methyl-1-(3-methylphenyl)-5-phenyl-1H-pyrazolo[4,3-e]-
[1,2,4]triazine (3d). This compound was obtained in a 60%
yield; mp 169 °C; 1H nmr (CDCl3): ꢀ 2.50 (s, 3H, CH3), 2.82 (s,
3H, SCH3), 7.15-7.21 (m, 1H, phenyl), 7.41-7.50 (m, 1H,
phenyl), 7.53-7.61 (m, 3H, phenyl), 8.18-8.27 (m, 2H, phenyl),
8.64-8.70 (m, 2H, phenyl); hrms (m/z) for C18H15N5: 301.13682
(M+); Calcd. 301.13275. Anal. Calcd. for C18H15N5: C, 71.76; H,
5.02; N, 23.25. Found: C, 71.87; H, 4.98; N, 23.11.
1-(2-Chlorophenyl)-3-methyl-5-methylsulfanyl-1H-pyra-
zolo[4,3-e][1,2,4]triazine (3e). This compound was obtained in
a 51% yield; mp 84 °C; H nmr (CDCl3): ꢀ 2.74 (s, 3H, CH3),
General Procedure for the Synthesis of Phenylhydrazones
of 5-Acetyl-3-alkoxy-1,2,4-triazine (1m,n). To a solution of 1a
(130 mg, 0.5 mmol) in anhydrous methanol or ethyl alcohol (20
1