Regioselectivity of cyclization of 1-(6-methyl-5-oxo-2,5-dihydro-1,2,4- triazin-3-yl)-4-arylthiosemicarbazides by treating with methyl iodide and dicyclohexylcarbodiimide

Article abstract of DOI:10.1134/S1070428010110138

1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-4-arylthiosemicarbazides treated with methyl iodide in the presence of sodium acetate in ethanol convert into 6-methyl-3-arylamino[1,2,4]-triazolo[4,3-b][1,2,4]triazin-7(1H)-ones. In reaction with dicyclohexylcarbodiimide 6-methyl-3-arylamino[1,2,4]triazolo[3,4- c][1,2,4]triazin-5(1H)-ones were obtained which at heating in alcohol solution in the presence of sodium acetate or at 262-272°C underwent the Dimroth rearrangement to give 3-methyl-7-arylamino[1,2,4]triazolo[5,1-c][1,2,4]-triazin- 4(8H)-ones. Pleiades Publishing, Ltd., 2010.

Full text of DOI:10.1134/S1070428010110138

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 11, pp. 1682−1686. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © R.I. Vas’kevich, P.V. Savitskii, E.B. Rusanov, V.I. Staninets, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 11,
pp. 1675−1679.
Regioselectivity of Cyclization
of 1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-4-arylthio-
semicarbazides by Treating with Methyl Iodide
and Dicyclohexylcarbodiimide
R. I. Vas’kevich, P. V. Savitskii, E. B. Rusanov, and V. I. Staninets
Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev, 0209 Ukraine
e-mail: vaskevich@ioch.kiev.ua
Received August 12, 2009
Abstract—1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-4-arylthiosemicarbazides treated with methyl iodide
in the presence of sodium acetate in ethanol convert into 6-methyl-3-arylamino[1,2,4]-triazolo[4,3-b][1,2,4]triazin-
7(1H)-ones. In reaction with dicyclohexylcarbodiimide 6-methyl-3-arylamino[1,2,4]triazolo[3,4-c][1,2,4]triazin-
5(1H)-ones were obtained which at heating in alcohol solution in the presence of sodium acetate or at 262–272°C
underwent the Dimroth rearrangement to give 3-methyl-7-arylamino[1,2,4]triazolo[5,1-c][1,2,4]-triazin-4(8H)-ones.
DOI: 10.1134/S1070428010110138
We studied formerly the cyclization of 1-hetaryl-4- Ia–Ic the stretching vibrations of the carbonyl group are
aryl-thiosemicarbazides (Ht = 4,6-dimethylpyrimidin- observed in the region 1660–1640 cm–1 confirming the
2-yl, 6-methyl-4-oxo-3,4-dihydropyrimidin-2-yl, sp2-hybridization of the atom N4.
5,6-substituted 4-oxo-3-allylthieno[2,3-d]pyrimidin-
2-yls and 4-oxo-3,4-dihydrothieno[2,3-d]pyrimidin-2-
yls, benzothiazol-2-yl) effected by methyl iodide and
sodium acetate in ethanol. Thus the fused derivatives
of triazolopyrimidine [1], triazolothienopyrimidine [2]
were obtained, and in the case of Ht = benzothiazol-2-yl
the reaction product was unexpectedly 2,2’-dithiobis[N-
(3-methylmercapto-4-phenyl-1,2,4-triazol-5-yl)
benzenamine] [3].
Taking into consideration the above reasoning, the
dependence of the regiochemistry of the fusion of the
triazole ring in the thiosemicarbazides Ia–Ic on the nature
of the electrophilic cyclization agent is a timely question.
For its solution we used as the cyclization reagents methyl
iodide and dicyclohexylcarbodiimide (DCC) [4]. As we
had shown before [1, 2] the cyclization effected by the
methyl iodide consisted first in the alkylation with the
methyl iodide of the thione sulfur of the thiosemicarbazide
In extension of the research on the cyclization with the intermediate formation of thioether which
regioselectivity of the hetaryl-substituted thiosemi- further suffered the intramolecular cyclization forming
carbazides we synthesized a thiosemicarbazide containing a triazole ring and eliminating a methylmercaptan. At
as a hetaryl fragment a 6-methyl-5-oxo-2,5-dihydro- the use of DCC the reaction begins with its addition to
1,2,4-triazine ring whose N2 and N4 atoms could be the sulfur atom of the thiosemicarbazide fragment with
involved into the closure of the triazole ring in the reaction the formation of the dicyclohexylthiourea and a new
with the methyl iodide in the presence of sodium acetate. carbodiimide, that further can attack one of the nitrogen
As show the 1H NMR spectra of compounds Ia–Ic in the atoms of the triazine heterocycle. This difference in
triazine ring of the thiosemicarbazides the hydrogen atom the action of the cyclization reagents suggests that the
is situated at the N2 atomas indicated by the chemical shift cyclization regiochemistry of these processes may be
in the region 12.59–12.64 ppm. In the 13C NMR spectrum different. Apparently the difference in the experimental
of compound Ia the chemical shift of the atom C5 is conditions also should be taken into account: with the
160.15 ppm, and in the IR spectra of thiosemicarbazides methyl iodide the sodium acetate is used that can produce
1682

REGIOSELECTIVITY OF CYCLIZATION OF 1-(6-METHYL-5-OXO-2,5-DIHYDRO-...
1683
a basic medium whereas with DCC the medium is neutral.
Main geometrical parameters of intermolecular hydrogen
bonds in the crystal of compound IIa dihydrate
It was established that in the reaction of
1-(6-methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-4-
arylthiosemicarbazides Ia–Ic with methyl iodide and
sodium acetate in ethanol 6-methyl-3-arylamino[1,2,4]
triazolo[4,3-b][1,2,4]triazin-7(1H)-ones IIa–IIc were
formed (see the scheme).
DHA angle,
D–H⋯Aa
H⋯A, Å D⋯A, Å
D–H, Å
deg
N5–H5N⋯N3#1
N6–H6N⋯O2
O2–H1O⋯O3#2
O3–H3O⋯N4
1.00(3)
0.89(3)
1.90(3) 2.882(3)
2.05(3) 2.900(3)
165(2)
159(2)
160(4)
165(7)
175(5)
0.816(10) 2.148(18) 2.926(4)
0.819(10) 2.17(2) 2.968(3)
0.824(10) 1.964(11) 2.786(3)
The structure of triazolotriazine IIa was established
by XRD analysis. The molecule of compound IIa crystal-
lized with two molecules of solvate water (see the figure
and the table). The distribution of the bond distances and
bond angles in the central bicyclic fragment is common
for such systems. The proper bicyclic fragment is virtually
planar, the average deviation of atoms from the mean-
square plane is 0.017 Å, and the phenyl ring C6–C11 is
materially coplanar with it (the dihedral angle is 2.5°).
The bonds N6–C4 1.348(3) and N6–C6 1.409(3) Å are
somewhat shortened [5] as compared with the standard
(1.45 Å) length of the ordinary nitrogen-carbon bond, and
the sum of the bond angles at the atom N6 is 359.6(16)°
indicating the conjugation of the lone electron pairs of
the atom N6 with the π-systems of the phenyl and the
heterocyclic system.
O3–H4O⋯O1#1
a
With indices #1 and #2 atoms are marked connected with the initial
symmetrical transformations –x + 1, –y + 1, –z and x, y – 1, z, re-
spectively.
spectra the stretching vibrations of the carbonyl group ap-
peared in the region 1700 cm–1, whereas for the triazolo-
triazines IIa–IIc ν(C=O) was 1600 cm–1. In the 13C NMR
spectrum of compound IIa the chemical shift of C7 atom
of the triazolotriazine system equals 160.55 ppm, and in
the spectrum of compound IIIa the chemical shift of the
atom C5 is observed in the stronger field at 153.02 ppm.
This permits a conclusion that the atom N4 of triazolotri-
azine IIIa is in the sp3-hybridized state. In the 1H NMR
spectra of compounds III the singlet of the proton of the
NHAr group is located at 8.61–9.25 ppm, and the proton
of the triazole ring, in the region 13.53–13.72 ppm. In
the spectra of triazolotriazines II the singlet of the NHAr
group appears at 9.55–10.21 ppm, and the proton of the
triazole ring, in the region 13.17–13.29 ppm.
The cyclization of compounds Ia–Ic with DCC in
toluene takes another route. In this case the yield of
triazolotriazines IIa–IIc was only 5–12%. To the main
reaction products isolated in 63–73% yield we assigned
the structure of 6-methyl-3-arylamino[1,2,4]triazolo[3,4-
c][1,2,4]-triazin-5(1H)-ones IIIa–IIIc because in their IR
Scheme.
Ar = C6H5 (a), 4-CH3OC6H4 (b), 4-C2H5O2CC6H4 (c).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 11 2010

VAS’KEVICH et al.
1684
spectra of compounds Ia, IIa, IIIa, on a spectrometer
Bruker Avance DRX-500 (125.75 MHz) in DMSO-d6,
internal reference TMS.
XRD experiment with a single crystal of compound
IIa of dimensions 0.14×0.20×0.41 mm was carried out
at room temperature on a diffractometer Bruker Smart
Apex II (λMoKα-radiation, graphite monochromator,
θmax 26.59 °, spherical segment –8 ≤ h ≤ 8, –8 ≤ k ≤ 10,
–13 ≤ l ≤ 10). 5200 reflections were collected, among
them 2560 independent (R-factor of averaging 0.0381).
Crystals of compound IIa [C11H14N6O3·2H2O, M 278.28]
triclinic, space group P-1, a 6.9904(13), b 8.6791(12),
c 11.1457(17) Å, α 96.634(8), β 107.721(9), γ 92.126(9)°,
V 637.95(18) Å3, Z 2, dc 1.449, μ 0.110 mm–1, F(000)
292. The structure was solved by the direct method and
refined by the lest-mean-squares method in the full-matrix
anisotropic approximation applying software SHELXS97
and SHELXL97 [6, 7]. The correction for extinction was
done using SADABS program (the ratio of minimal to
maximal correction Tmin/Tmax 0.755221). Hydrogen atoms
were revealed in the difference Fourier synthesis and were
refined isotropically. In the refinement 1430 reflections
were used with I > 2σ(I), 237 refined parameters, 6.03
reflections per a parameter, the weight scheme was used
ω = 1/[σ2(Fo ) + (0.0513P)2] where P = (Fo2 + 2Fc )/3,
the ratio of the maximum (average) shift to the error
in the final cycle 0.09 (0.004). The final values of the
divergence factors R1(F) 0.0540, wR2(F2) 0.1136, GOF
1.067 for the reflections with I > 2σ(I). The residual
electron density from the difference Fourier series after
the final refinement cycle was 0.18 and –0.24 e/ Å3. The
complete set of the XRD structural data for compound
IIa is deposited in the Cambridge Crystallographic Data
Center (CCDC 741347).
General view of molecule 6-methyl-3-phenylamino[1,2,4]-
triazolo-[4,3-b][1,2,4]triazin-7(1H)-one (IIa) dihydrate. The
main bond distances and bond angles: N1–N2 1.360(3), N2–C1
1.356(3), N3–C1 1.332(3), N3–C2 1.359(3), C2–C3 1.494(3), N1–
C3 1.296(3), N2–C4 1.379(3), N4–C4 1.308(3), N4–N5 1.396(3),
N5–C1 1.314(3), N6–C4 1.348(3) Å; C3N1N2 113.62(19),
C1N2N1 124.64(19), N3C1N2 124.1(2), C1N3C2 114.6(2),
N3C2C3 119.5(2), N1C3C2 123.3(2), C1N2C4 108.07(19),
N4C4N2 110.0(2), C4N4N5 104.42(18), C1N5N4 111.96(19),
N5C1N2 105.58(19) deg.
Compounds IIIa–IIIc at heating with sodium acetate
in ethanol or without solvent at 262–272°C suffered the
Dimroth rearrangement with the formation of 3-methyl-7-
arylamino[1,2,4]triazolo-[5,1-c][1,2,4]triazin-4(8H)-ones
IVa–IVc. Triazolotriazines IIa–IIc are less prone to the
isomerization, but at melting compound IIa the partial
formation of triazolotriazine IVa was observed in 10–15%
yield. Further heating of the sample of compound IIa over
315°C led to its decomposition.
2
2
In the IR spectra of compounds IVa–IVc the stretching
vibrations of the carbonyl group are observed in the region
1670–1690 cm–1. In the 1H NMR spectra of compounds
IV unlike the spectra of compounds III the singlets of
the protons of the NHAr group and of the triazole ring
are shifted downfield, to 9.61–10.35 and 14.07–14.23
ppm respectively.
3-Hydrazino-6-methyl-1,2,4-triazin-5(2H)-one was
obtained by procedure [8].
1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-
yl)-4-arylthiosemicarbazides Ia–Ic. To a dispersion of
0.71 g (5 mmol) of 3-hydrazino-6-methyl-1,2,4-triazin-
5(2H)-one in 30 ml of ethanol was added a solution of
6 mmol of an appropriate isothiocyanate in 20 ml of
ethanol. The mixture was boiled for 1.5 h and then cooled.
The precipitated crystals of the thiosemicarbazide were
filtered off and washed with ethanol and ether.
Thus the cyclization of compounds Ia–Ic proceeded
under the action of methyl iodide selectively at
the atom N2 of the triazine ring, and with DCC,
unselectively, both at the atom N4 and the atom
N2. Compounds IIIa–IIIc can undergo thermal and
catalytic Dimroth rearrangement.
EXPERIMENTAL
1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-
4-phenylthiosemicarbazide (Ia). Yield 1.12 g (81%), mp
281–283°C (decomp.). IR spectrum, ν, cm–1: 3320, 3280,
1690, 1660, 1590, 1560, 1510, 1440, 1340, 1280, 1240,
IR spectra were recorded on a spectrophotometer UR-
20 in pellets with KBr. 1H NMR spectra were registered
on a spectrometer Varian VXR-300 (300 MHz), 13C NMR
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 11 2010

REGIOSELECTIVITY OF CYCLIZATION OF 1-(6-METHYL-5-OXO-2,5-DIHYDRO-...
1685
1210, 1160. 1H NMR spectrum, δ, ppm: 2.06 s (3H, CH3),
7.16 t (1Harom, J 7.5 Hz), 7.33 t (2Harom, J 7.5 Hz), 7.53 d
(2Harom, J 7.5 Hz), 9.39 br.s (1H, NH), 9.59 C (1H, NH),
10.02 c (1H, NH), 12.59 c (1H, NH). 13C NMR spectrum,
δ, ppm: 15.94, 113.99, 115.81, 128.80, 138.27, 146.59,
148.32, 151.43, 160.15. Found, %: C 47.56; H 4.21;
N 30.33; S 11.47. C11H12N6OS. Calculated, %: C 47.81;
H 4.38; N 30.41; S 11.60.
6 - M e t h y l - 3 - ( 4 - m e t h o x y p h e n y l a m i n o )
[1,2,4]-triazolo[4,3-b][1,2,4]triazin-7(1H)-one (IIb).
Yield 0.46 g (67%), mp 230–232°C (acetone). IR
spectrum, ν, cm–1: 3270, 3100, 1590, 1550, 1420, 1230,
1170, 1020, 870, 820. 1H NMR spectrum, δ, ppm: 2.29 s
(3H, CH3), 3.73 s (3H, OCH3), 6.91 d (2Harom, J 9.0 Hz),
7.62 d (2Harom, J 9.0 Hz), 9.55 s (1H, NH), 13.21 br.s (1H,
NH). Found, %: C 52.87; H 4.35; N 30.76. C12H12N6O2.
Calculated, %: C 52.94; H 4.44; N 30.87.
1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-
4-(4-methoxyphenyl)thiosemicarbazide (Ib). Yield
1.13 g (74%), mp 189–191°C. IR spectrum, ν, cm–1:
3300, 1640, 1550, 1520, 1430, 1360, 1300, 1240, 1170,
1040. 1H NMR spectrum, δ, ppm: 2.07 s (3H, CH3), 3.75 s
3-(4-Carboethoxyphenylamino)-6-methyl[1,2,4]-
triazolo[4,3-b][1,2,4]triazin-7(1H)-one (IIc). Yield
0.50 g (63%), mp 302–303°C (acetone). IR spectrum,
ν, cm–1: 3320, 1670 (C=O), 1590, 1550, 1430, 1270,
1240, 1080. 1H NMR spectrum, δ, ppm: 1.32 t (3H, CH3,
J 7.2 Hz), 2.30 s (3H, CH3), 4.28 q (2H, CH2, J 7.2 Hz),
7.81 d (2Harom, J 9.0 Hz), 7.92 d (2Harom, J 9.0 Hz),
10.21 s (1H, NH), 13.29 br.s (1H, NH). Found, %:
C 53.45; H 4.39; N 26.67. C14H14N6O3. Calculated, %:
C 53.50; H 4.49; N 26.74.
(3H, OCH3), 6.90 d (2Harom, J 9.0 Hz), 7.36 d (2Harom
,
J 9.0 Hz), 9.36 br.s (1H, NH), 9.51 s (1H, NH), 9.93 s
(1H, NH), 12.60 s (1H, NH). Found, %: C 46.94; H 4.58;
N 27.31; S 10.38. C12H14N6O2S. Calculated, %: C 47.05;
H 4.61; N 27.43; S 10.47.
1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-
4-(4-carboethoxyphenyl)thiosemicarbazide (Ic). Yield
1.45 g (83%), mp 284–286°C (decomp.). IR spectrum, ν,
cm–1: 3320, 3270, 1700, 1660 (C=O), 1610, 1590, 1560,
1460, 1410, 1340, 1310, 1280, 1210, 1190, 1110, 1030.
1H NMR spectrum, δ, ppm: 1.32 t (3H, CH3, J 7.2 Hz),
2.07 s (3H, CH3), 4.31 q (2H, CH2, J 7.2 Hz), 7.80 d
(2Harom, J 8.7 Hz), 7.93 d (2Harom, J 8.7 Hz), 9.46 br.s
(1H, NH), 9.83 s (1H, NH), 10.26 s (1H, NH), 12.64 br.s
(1H, NH). Found, %: C 47.99; H 4.57; N 24.05; S 9.13.
C14H16N6O3S. Calculated, %: C 48.27; H 4.63; N 24.12;
S 9.20.
Reaction of 1-(6-methyl-5-oxo-2,5-dihydro-
1,2,4-triazin-3-yl)-4-arylthiosemicarbazides Ia–Ic
with DCC. A dispersion of 2.5 mmol of an appropriate
thiosemicarbazide Ia–Ic, 0.93 g (4.5 mmol) of DCC in
50 ml of toluene was boiled for 1.5 h on an oil bath at
115–120°C. The solution was cooled to 25–30°C, the
precipitated crystals of compound III were filtered off and
washed on the filter with toluene and ether. The filtrate
was completely evaporated, 20 ml of ethanol was added,
and the mixture was heated till the precipitate dissolved.
From the solution by the fractional crystallization were
obtained compounds (IIa) 7%, (IIb) 12%, (IIc) 5%.
6-Methyl-3-arylamino[1,2,4]triazolo[4,3-b]-[1,2,4]
triazin-7(1H)-ones IIa–IIc. Adispersion of 2.5 mmol of an
appropriate thiosemicarbazide Ia–Ic, 0.25 g (3 mmol) of
sodium acetate, and 0.19 ml (3 mmol) of methyl iodide
was boiled for 1.5 h in 50 ml of ethanol. The solution
was cooled, the precipitated crystals were filtered off and
washed on the filter with ethanol and ether.
6-Methyl-3-phenylamino[1,2,4]triazolo-
[3,4-c]-[1,2,4]triazin-5(1H)-one (IIIa). Yield 0.40 g
(66%), mp 264–266°C,* 330–332°C (ethanol–DMSO). IR
spectrum, ν, cm–1: 1700, 1630, 1600, 1560, 1500, 1460,
1
1380, 1350, 1290, 1250. H NMR spectrum, δ, ppm:
2.22 s (3H, CH3), 6.98 t (1Harom, J 7.5 Hz), 7.34 t (2Harom
,
J 7.8 Hz), 7.71 d (2Harom, J 7.8 Hz), 8.78 s (1H, NH),
13.60 s (1H, NH). 13C NMR spectrum, δ, ppm: 15.27,
117.06, 121.28, 128.84, 135.81, 139.47, 144.15, 145.25,
153.02. Found, %: C 54.28; H 4.07; N 34.53. C11H10N6O.
Calculated, %: C 54.54; H 4.16; N 34.69.
6-Methyl-3-phenylamino[1,2,4]triazolo-
[4,3-b]-[1,2,4]triazin-7(1H)-one (IIa). Yield 0.44 g
(73%), mp 296–297°C (acetone). IR spectrum, ν, cm–1:
1
1600, 1560, 1500, 1460, 1420, 1300, 1240. H NMR
spectrum, δ, ppm: 2.31 s (3H, CH3), 6.99 t (1Harom
J 7.5 Hz), 7.33 t (2Harom, J 7.5 Hz), 7.72 d (2Harom
,
,
6 - M e t h y l - 3 - ( 4 - m e t h o x y p h e n y l a m i n o )
[1,2,4]-triazolo[3,4-c][1,2,4]triazin-5(1H)-one (IIIb).
Yield 0.43 g (63%), mp 262–263°C,* 341–343°C
(ethanol–DMSO). IR spectrum, ν, cm–1: 3370, 2860,
1700, 1640, 1600, 1560, 1510, 1430, 1380, 1340, 1290,
1270, 1240, 1190, 1140, 1040. 1H NMR spectrum, δ, ppm:
J 8.1 Hz), 9.74 s (1H, NH), 13.17 s (1H, NH). 13C NMR
spectrum, δ, ppm: 17.88, 117.44, 121.50, 128.78, 139.40,
141.98, 147.14, 153.26, 160.55. Found, %: C 54.53;
H 4.09; N 34.67. C11H10N6O. Calculated, %: C 54.54;
H 4.16; N 34.69.
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VAS’KEVICH et al.
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2.20 s (3H, CH3), 3.73 s (3H, OCH3), 6.91 d (2Harom
,
1H NMR spectrum, δ, ppm: 2.28 s (3H, CH3), 3.72 s
(3H, OCH3), 6.92 d (2Harom, J 9.0 Hz), 7.58 d (2Harom
J 9.0 Hz), 9.61 s (1H, NH), 14.07 s (1H, NH). Found, %:
C 52.83; H 4.37; N 30.71. C12H12N6O2. Calculated, %:
C 52.94; H 4.44; N 30.87.
J 8.7 Hz), 7.64 d (2Harom, J 9.0 Hz), 8.61 s (1H, NH),
13.53 s (1H, NH). Found, %: C 52.77; H 4.28; N 30.68.
C12H12N6O2. Calculated, %: C 52.94; H 4.44; N 30.87.
,
3-(4-Carboethoxyphenylamino)-6-methyl[1,2,4]-
triazolo[3,4-c][1,2,4]triazin-5(1H)-one (IIIc). Yield
0.57 g (73%), mp 271–272°C,1 318–320°C (ethanol–
DMSO). IR spectrum, ν, cm–1: 1710 (C=O), 1630, 1600,
1560, 1490, 1430, 1380, 1280, 1260, 1180, 1110, 1040.
1H NMR spectrum, δ, ppm: 1.32 t (3H, CH3, J 7.2 Hz),
2.22 s (3H, CH3), 4.29 q (2H, CH2, J 7.2 Hz), 7.79 d
(2Harom, J 9.0 Hz), 7.92 d (2Harom, J 8.7 Hz), 9.25 s (1H,
NH), 13.72 c (1H, NH). Found, %: C 53.39; H 4.37;
N 26.53. C14H14N6O3. Calculated, %: C 53.50; H 4.49;
N 26.74.
7-(4-Carboethoxyphenylamino)-3-methyl[1,2,4]-
triazolo[5,1-c][1,2,4]triazin-4(8H)-one (IVc). Yield
0.64 g (82%) (a), 0.76 g (98%) (b), mp 320–321°C
(ethanol). IR spectrum, ν, cm–1: 1690 (C=O), 1590, 1540,
1420, 1280, 1170, 1100, 1040, 1020. 1H NMR spectrum,
δ, ppm: 1.32 t (3H, CH3, J 7.2 Hz), 2.31 s (3H, CH3),
4.29 q (2H, CH2, J 7.2 Hz), 7.78 d (2Harom, J 9.0 Hz),
7.94 d (2Harom, J 9.0 Hz), 10.35 s (1H, NH), 14.23 s (1H,
NH). Found, %: C 53.46; H 4.46; N 26.75. C14H14N6O3.
Calculated, %: C 53.50; H 4.49; N 26.74.
3-Methyl-7-arylamino[1,2,4]triazolo[5,1-c]-[1,2,4]
triazin-4(8H)-ones IVa–IVc. a. Adispersion of 2.5 mmol
of an appropriate compound IIIa–IIIc, 0.25 g (3 mmol) of
sodium acetate was boiled for 1.5 h in 50 ml of ethanol.
The solution was cooled, the precipitated crystals were
filtered off and washed on the filter with ethanol and ether.
REFERENCES
1. Vas’kevich, R.I., Savitskii, P.V., Zborovskii, Yu.L., Stani-
nets, V.I., Rusanov, E.B., and Chernega, A.N., Zh. Org.
Khim., 2006, vol. 42, p. 1417.
2. Vas’kevich, R.I., Savitskii, P.V., Zborovskii, Yu.L., Stani-
nets, V.I., Turov,A.V., and Chernega,A.N., Zh. Org. Khim.,
2006, vol. 42, p. 1411.
b. 1 mmol of an appropriate compound IIIa–IIIc
was heated for 5 min on a sand bath at 262–272°C.
The obtained white crystalline product did not require
additional purification.
3. Savitskii, P.V., Vas’kevich, R.I., Zborovskii, Yu.L., Stani-
nets, V.I., But, S.A., and Chernega, A.N., Zh. Org. Khim.,
2008, vol. 44, p. 407.
3-Methyl-7-phenylamino[1,2,4]triazolo-
[5,1-c]-[1,2,4]triazin-4(8H)-one (IVa). Yield 0.56 g
(93%) (a), 0.60 g (99%) (b), mp 331–332°C (ethanol).
IR spectrum, ν, cm–1: 1690, 1650, 1620, 1570, 1500,
1460, 1180, 1060. 1H NMR spectrum, δ, ppm: 2.31 s (3H,
CH3), 6.95 t (1Harom, J 7.5 Hz), 7.33 t (2Harom, J 8.1 Hz),
7.69 d (2Harom, J 8.1 Hz), 9.84 s (1H, NH), 14.13 s (1H,
NH). Found, %: C 54.34; H 4.12; N 34.57 C11H10N6O.
Calculated, %: C 54.54; H 4.16; N 34.69.
4. Bishop, B.C., Marley, H., Preston, P.N., and Wright, S.H.B.,
J. Chem. Soc., Perkin, Trans. 1, 1999, p. 1527
5. Allen, F.H., Kennard, O., Watson, D.G., Brammer, L.,
Orpen, A.G., and Tailor, R. J. Chem. Soc., Perkin, Trans.
2, 1987, p. 1.
6. Sheldric, G.M., SHELXS97. Program for the Solution of
Crystal Structure, University of Göttingen, Germany, 1997.
7. Sheldric, G.M., SHELXL97. Program for the Refinement
of Srystal Structures, University of Göttingen, Germany,
1997.
3-Methyl-7-(4-methoxyphenylamino)[1,2,4]
triazolo[5,1-c][1,2,4]triazin-4(8H)-one (IVb). Yield
0.58 g (85%) (a), 0.68 g (99%) (b), mp 343–345°C
(ethanol). IR spectrum, ν, cm–1: 3280, 3120, 3010, 1670,
1610, 1570, 1500, 1430, 1390, 1240, 1210, 1170, 1030.
8. Dornow, A., Abele, W., and Menzel, H., Chem. Ber., 1964,
vol. 97, p. 2179.
1 In this temperature range occurred Dimroth rearrangement with the
formation of compounds IVa–IVc.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 11 2010