Molbank 2005, M434 |
e-mail: [email protected]
Received:
Keywords: semicarbazone, thiosemicarbazone, 5-acetyl-1,2,4-triazine.
Semicarbazone as well as thiosemicarbazone of 5-acetyl-3-(methylsulfanyl)-1,2,4-triazine were synthesised
as reactive intermediates for the synthesis of 1H-pyrazolo[4,3-e][1,2,4]triazine derivatives via
acid promoted ring closure [1-3].
Starting ketone 1 was
prepared according to a reported procedure [4]. To a solution of ketone 1 (169
mg, 1 mmol) and semicarbazone
or thiosemicarbazone (1.2 mmol)
in ethanol (20 ml) 10% HCl (0.5 ml) was added. The resulting
reaction mixture was heated at reflux for 5 min and then stirred at room
temperature for additional 30 min. The precipitated solid was filtered off, recrystallized from dioxane and
dried under vacuum.
Semicarbazone of 5-acetyl-3-(methylsulfanyl)-1,2,4-triazine (2)
Yield 89%.
Melting Point: 260ºC.
1H-NMR (200 MHz, DMSO-d6): ¦Ä= 2.19 (s, 3H); 2.62
(s, 3H); 6.96 (s, 2H, NH2); 9.98 (s, 1H); 10.13 (s,
IR (CHCl3
film, cm-1): 3339; 3106; 1693; 1520; 1486; 1426; 1312; 1256; 1183; 1133;
1058; 871; 713.
MS- EI (m/z,
%): 226 (18) [M+]; 209 (7); 184 (11); 183 (100); 182 (62); 155 (12);
154 (39); 140 (32); 82 (49); 81 (30); 74 (18); 53 (19).
HR-MS:
Calculated for C7H10N6OS: 226.0636. Found:
226.06314.
Thiosemicarbazone of 5-acetyl-3-(methylsulfanyl)-1,2,4-triazine (3)
Yield 87%.
Melting Point: 229ºC.
IR (CHCl3 film, cm-1): 3304; 3158; 2969; 1587; 1495; 1423;
1243; 1127; 1057; 876.
1H-NMR (200 MHz, DMSO-d6): ¦Ä= 2.31 (s, 3H); 2.63
(s, 3H); 8.53 (s, 1H); 8.70 (s, 1H); 10.08 (s, 1H); 10.81 (s, 1H).
MS-EI (m/z,
%): 242 (80) [M+]; 199 (21); 167 (7); 154 (6); 141 (5); 140 (22);
128 (27); 116 (100); 82 (12); 81 (12); 74 (14); 60 (24); 53 (13).
HR-MS: Calculated
for C7H10N6S2:
242.04084; Found: 242.04129.
References:
1.Rykowski, A.; Mojzych, M.; Karczmarzyk, Z. Heterocycles, 2000, 53, 2175.
2.Mojzych,
M.; Rykowski, A. Polish
J. Chem., 2003, 77, 1797.
3.Mojzych,
M.; Rykowski, A. Heterocycles,
2004, submitted.
4.Rykowski,
A.; Lipi¨½ska, T. Synth. Comm., 1996, 26, 4409.
Sample
Availability: Available
from MDPI.
© 2005 MDPI. All rights reserved.