Synthesis of 4-amino-6-phenyl-3-thioxo-2,3-dihydro-1,2,4-triazine-5(4H)-one

Full text of DOI:10.1023/A:1012376712024

Russian Journal of General Chemistry, Vol. 71, No. 6, 2001, pp. 991 992. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 6, 2001,
pp. 1052 1053.
Original Russian Text Copyright
2001 by Mironovich, Salistaya, Promonenkov.
LETTERS
TO THE EDITOR
Synthesis of 4-Amino-6-phenyl-3-thioxo-2,3-dihydro-
,2,4-triazine-5(4H)-one
1
L. M. Mironovich, G. S. Salistaya, and V. K. Promonenkov
Sumy State University, Sumy, Russia
Received September 25, 2000
4
-Amino-1,2,4-triazine derivatives have found
0 C of 6-phenyl-3-thioxo-2,3-dihydro-1,2,4-triazine-
5(4H)-one (III). The characteristics and properties of
compound I have been described in [2].
application as pesticides. They are commonly pre-
pared by condensation of -ketocarboxylic acids with
thiosemicarbazide in alkaline medium [1]. In the
present work we studied reactions of 4-nitroso-6-
phenyl-3-thioxo-2,3-dihydro-1,2,4-triazine-5(4H)-one
The reaction of compound I with acetylacetone
like the Ehrlich Sachs reaction of aromatic com-
(
pounds) in weakly alkaline medium resulted in pre-
paration of 4-(diacetylmethyleneamino)-6-phenyl-3-
thioxo-2,3-dihydro-1,2,4-triazine-5(4H)-one (IV) [3].
Hydrolysis of compound IV in aqueous alcohol in the
presence of acid gave 4-amino-6-phenyl-3-thioxo-2,3-
dihydro-1,2,4-triazine-5(4H)-one (II). The mechanism
of the hydrolysis is usual for azomethines.
(
I), involving the nitroso group, with the aim of pre-
paring 4-amino-6-phenyl-3-thioxo-2,3-dihydro-1,2,4-
triazine-5(4H)-one (II) by previously unknown
methods.
Compound I was prepared by direct nitrosation
with sodium nitrite in hydrochloric acid medium at
O
Ph
(
CH CO) C=N N
3
2
CH COCH COCH
3
3
2
N
S
O
N
H
ON
Ph
N
N
IV
Ph
S
N
H
I
O
H N
2
Zn, AcOH
N
N
S
N
H
II
4
-Aminotriazines proved difficult to prepare by
bond of the triazine ring to give 6-phenyl-3-thioxo-
1,2,3,6-tetrahydro-1,2,4-triazine-5(4H)-one [4].
reduction of substituted 4-nitrosotriazines because of
the attendant reduction of the triazine ring and cleava-
ge of the nitroso group. The reductions with hydrazine
hydrate or tin(II) chloride involved cleavage of the
nitroso group to provide 6-phenyl-3-thioxo-2,3-di-
hydro-1,2,4-triazine-5(4H)-one (III). Boiling with
phenyl hydrazine resulted, along with cleavage of the
Boiling of 4-nitrosotriazine (I) with zinc powder
in acid medium gave 4-amino-6-phenyl-3-thioxo-2,3-
dihydro-1,2,4-triazine-5(4H)-one (II) whose charac-
terstics and properties were coincident with those of a
sample isolated upon hydrolysis of compound IV and
described in [5]. The reduction of the nitroso group
6
1
nitroso group, in further hydrogenation of the C N
1
070-3632/01/7106-0991$25.00 2001 MAIK Nauka/Interperiodica

992
MIRONOVICH et al.
with zinc powder in acid medium probably occurs like
the Clemmensen reaction of carbonyl compounds.
Presumably, the oxygen is cleaved as water from a
partly reduced intermediate bound with zinc.
H 3.6; N 25.1. C H N OS. Calculated, %: C 49.08;
H 3.66; N 25.44.
9
8
4
The IR spectra were recorded on a UR-10 instru-
1
ment in KBr pellets. The H NMR spectra were ob-
4
-Amino-6-phenyl-3-thioxo-2,3-dihydro-1,2,4-
triazine-5(4H)-one (II). a. Compound I, 2.34 g, and
0 g of zinc powder were boiled in 100 ml of glacial
tained on a Tesla BS-487B spectrometer at 80 MHz
in DMSO-d , internal reference HMDS. The purity of
6
1
the reaction products was checked by TLC on Silufol
UV-254 plates in the system chloroform acetone, 1:9.
acetic acid for 30 40 min until decoloration. The
mixture was then filtered while hot, the filtrate was
reduced to one third in a vacuum, and the residue was
cooled and diluted with water (1:3). The precipitate
was filtered, washed with water, dried in air, and re-
crystallized from isopropanol. Yield 1.17 g (53%),
mp 231 C (tarring).
REFERENCES
1. Mironovich, L.M. and Promonenkov, V.K.. Itogi Nauki
Tekh., Ser. Org. Khim., 1990, vol. 22, pp. 3 267.
2
. Mironovich, L.M., Promonenkov, V.K., and Kry-
sin, V.P., Khim. Geterotsikl. Soedin., 1986, no. 3,
pp. 400 402.
b. Compound IV, 3.16 g, was boiled in a 1:1 iso-
propanol water mixture and 5 ml of conc. HCl for
1
2 h. The mixture was filtered while hot, the filtrate
3
. Mironovich, L.M., Khim. Geterotsikl. Soedin., 1998,
no. 5, pp. 698 700.
was cooled, the precipitate was filtered off, dried in
air, and recrystallized from isopropanol. Yield 1.82 g
1
4. Mironovich, L.M., Khim. Geterotsikl. Soedin., 1996,
(
1
83%), mp 231 C (tarring). IR spectrum, , cm :
650 (C=O); 1190 (C=S); 3300, 3200 (NH ). H
1
no. 10, pp. 1421 1423.
2
NMR spectrum, , ppm: 7.50 7.87 m (5H, Ph), 5.92 s
2H, NH ), 13.43 s (1H, NH). Found, %: C 48.9;
5. Dornow, A., Menzel, H., and Marx, P., Chem. Ber.,
(
1964, vol. 57, no. 8, pp. 2173 2178.
2
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 6 2001