Utilization of Cleavage of the [1]Benzofuro[2,3-e][1,2,4]triazine Ring for the Synthesis of Oxygen, Nitrogen and Sulfur Derivatives of [1,2,4]Triazine [1]

Article abstract of DOI:10.1002/jhet.5570400509

A series of 6-azacytosines 4a-4k and 5a-5c were prepared by nucleophilic cleavage of furan ring of [1]benzofuro[2,3-e][1,2,4]triazine derivative 1. Some of them were used for the preparation of derivatives of [1,2,4]triazolo[4,3-d][1,2,4]triazine (6a-6d)

Full text of DOI:10.1002/jhet.5570400509

Sep-Oct 2003
805
Utilization of Cleavage of the [1]Benzofuro[2,3-e][1,2,4]triazine Ring
for the Synthesis of Oxygen, Nitrogen and Sulfur Derivatives of
[1,2,4]Triazine [1]
*1a
1
1b
2c
Jakub Sty´skala , Jan Slouka , Iveta Wiedermannová and Petr Bednárˇ
1
Department of Organic Chemistry, Palacky´ University, 771 46 Olomouc, Czech Republic;
a
b
E-mail: styskala@prfnw.upol.cz, wiedermannova@prfnw.upol.cz
2
Department of Analytical Chemistry, Palacky´ University, 771 46 Olomouc, Czech Republic;
c
E-mail: bednar@prfnw.upol.cz
Received April 21, 2003
A series of 6-azacytosines 4a-4k and 5a-5c were prepared by nucleophilic cleavage of furan ring of
[1]benzofuro[2,3-e][1,2,4]triazine derivative 1. Some of them were used for the preparation of derivatives of
[1,2,4]triazolo[4,3-d][1,2,4]triazine (6a-6d) and tetrazolo[1,5-d][1,2,4]triazine (7). The reaction of 1 with
hydrogen sulfide afforded the corresponding 6-(2-hydroxyphenyl)-2-phenyl-5-thioxo-4,5-dihydro-1,2,4-tri-
azin-3(2H)-one (8), while with hydrogen selenide 6-(2-hydroxyphenyl)-2-phenyl-4,5-dihydro-1,2,4-triazin-
3(2H)-one (9) was formed. The prepared compounds were tested for biological activity.
J. Heterocyclic Chem., 40, 805 (2003).
A number of cleavage reactions of heterocyclic com-
means, that the aminolysis is preferred to hydrolysis. For
preparative reasons, we performed most experiments with-
out solvent or in a chloroform solution. The reaction of
compound 1 with aqueous ammonia afforded smoothly
5-amino-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-triazin-
3(2H)-one (4a). The same reaction was carried out using
primary and secondary amines, affording corresponding
N-substituted 6-azacytosines 4b-4k. To verify the use of
compound 1 as a reagent capable of binding to the free
amino groups of amino acids in proteins we also used
lysine in the above mentioned reactions to obtain the cor-
pounds are well-known and advantageous methods for the
preparation of compounds, which are otherwise available
with difficulties. For example, the synthesis of 1,4-disub-
stituted butanes based on the opening of furan [2] or
tetrahydrofuran [3,4] ring, or the synthesis of gluta-
conaldehyde and related compounds realized by ring
cleavage of pyridinium salts [5-8].
Previously, we found that the [1]benzofuro[2,3-e]-
[1,2,4]triazine system was very susceptible to the
hydrolytic cleavage of the furan ring [9-11]. This reaction
starts by nucleophilic attack of water to position 4a, thus
showing a high ability of this position to react with nucle-
ophilic reagents. It was interesting for us to know how eas-
ily these cleavage reactions could proceed with other
nucleophilic agents and whether it would be possible to
use this reaction for the introduction of required sub-
stituents at position 5 of the 1,2,4-triazine ring. The results
of this research, using some oxygen, nitrogen and sulfur
nucleophilic agents, are reported in this paper.
In all these cases, we found that opening of the furan
ring took place and the corresponding 5-substituted 1,2,4-
triazines were formed in good yields. So the reaction of
2-phenyl-2,3-dihydro[1]benzofuro[2,3-e][1,2,4]triazin-3-
one (1) with anhydrous ethanol led to 5-ethoxy-6-(2-
hydroxyphenyl)-2-phenyl-1,2,4-triazin-3(2H)-one (3). If
the ethanol was not strictly anhydrous or if aqueous
ethanol was used, the hydrolytic splitting of the furan ring
prevailed thus affording 6-(2-hydroxyphenyl)-2-phenyl-
1,2,4-triazine-3,5(2H,4H)-dione (2) which has been pre-
pared earlier [9,10] (Scheme 1).
As expected, the cleavage of the furan ring of compound
1 was easier when stronger nucleophilic agents, such as
primary and secondary amines or hydrazine and its deriva-
tives were used. We found that reaction with amines and
hydrazines took place even in aqueous solutions. This
6
responding N -[6-(2-hydroxyphenyl)-3-oxo-2-phenyl-2,3-
dihydro-1,2,4-triazin-5-yl]lysine (4d). Hydrazinolysis of
compound 1 with hydrazine, phenylhydrazine or semicar-
bazide proceeded smoothly and afforded the correspond-
ing 5-hydrazino-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-tri-
azin-3(2H)-one (5a) respectively their derivatives 5b and
5c (Scheme 1).
To demonstrate that the reaction can also proceed with
compounds containing more amino groups, we used
putrescine and spermidine as reactants to get more complex
derivatives 4j and 4k. These prepared substances are inter-
esting for their potential biological activity (Scheme 2).
Hydrazino derivatives 5a and 5c served as starting com-
pounds for the preparation of derivatives of [1,2,4]triazolo-
[4,3-d][1,2,4]triazine 6a-6d and tetrazolo[1,5-d]-
[1,2,4]triazine 7. Heating of compound 5a in formic acid
gave compound 6a without formylation of phenolic OH
group. In contrast, acetic anhydride acetylated the hydroxy
group to the derivative 6b as it was expected. The closure of
the fused triazole ring was also successful using carbon
disulfide affording compound 6c. An analogous oxo deriva-
tive 6d was obtained by thermal cyclization of semicarbazide
derivative 5c. 8-(2-Hydroxyphenyl)-6-phenyltetrazolo[1,5-
d][1,2,4]triazin-5(6H)-one (7) was obtained smoothly by the
nitrosation of the hydrazino derivative 5a (Scheme 3).

806
J. Sty´skala, J. Slouka, I. Wiedermannová and P. Bednárˇ
Vol. 40
Our further interest was to find out whether the nucleo-
philic opening of the furan ring could be achieved using
hydrogen sulfide. We found that the reaction took place
smoothly under base catalysis and afforded 6-(2-hydroxy-

Sep-Oct 2003
Utilization of Cleavage of the [1]Benzofuro[2,3-e][1,2,4]triazine Ring
807
EXPERIMENTAL
phenyl)-2-phenyl-5-thioxo-4,5-dihydro-1,2,4-triazin-
3(2H)-one (8). In contrast, the reaction of 1 with H Se pro-
2
The melting points were determined on a Boetius stage and are
uncorrected. The IR spectra were recorded in KBr wafers on an
ATI Unicam Genesis FTIR instrument. The NMR spectra were
registered on a Bruker AMX-360 spectrometer (360 MHz) and
on a Bruker Avance 300 MHz DRX spectrometer; chemical shifts
are reported in ppm, coupling constants J in Hz. Elemental analy-
ses were performed with an EA 1108 Elemental Analyser (Fison
Instrument). Mass spectra were recorded on an ion trap mass
spectrometer LCQ Finnigan Mat.
ceeded with the reduction of the triazine ring affording
6-(2-hydroxyphenyl)-2-phenyl-4,5-dihydro-1,2,4-triazin-
3(2H)-one (9). The cleavage of the furan ring in com-
pound 1 with H F was unsuccessful (Scheme 4).
2 2
Most of the prepared compounds have a similar struc-
ture with that of pyrimidine nucleobases. The prepared
compounds were tested for biological activity. Human
breast adenocarcinoma cell line MCF7 was used for cyto-
toxicity determination of prepared compounds by calcein
AM assay [12]. The tested azacytosines 4a-4k and 5a-5c
Cytotoxicity Determination of Prepared Compounds.
The tumour cells were maintained in plastic tissue culture
flasks and grown on Dulbecco’s modified Eagle’s cell culture
showed poor cytostatic activity (IC = 60-80 µmol/L)
50
with the exception of moderately active compounds 5c
medium (DMEM) at 37 °C in 5% CO atmosphere and 100%
2
humidity. The cell suspension of approximate density 1.25x105
(IC = 3.5 µmol/L) and 4a (IC50 = 23 µmol/L).
50
-1
cells ml was redistributed into 96-well microtitre plates (Nunc,
Denmark). After 12 h of preincubation, the tested compounds (in
the 0.5–200 µmol/l range) were added. Incubation lasted for 72 h.
At the end of this period, the cells were incubated for 1 h with
calcein AM and fluorescence of the live cells was measured at
485/538 nm (ex/em) with a Fluoroskan Ascent (Labsystems,
Finland). IC values, the drug concentrations lethal to 50% of
50
the tumour cells, were estimated.
6-(2-Hydroxyphenyl)-2-phenyl-1,2,4-triazine-3,5(2H,4H)-dione
(2).
A solution of compound 1 (20.2 mg, 0.077 mmol) in 50%
aqueous ethanol (5 ml) was refluxed for 1 h and then evaporated
to dryness. The residue was mixed with water (3 ml), collected by
filtration and dried at 120 °C for 1 h. Sample for analysis was
prepared by crystallization from ethanol. Yield 19.5 mg (90.3 %),
mp 261-263 °C. Spectral data were identical to the data of the
compound prepared earlier [9].

808
J. Sty´skala, J. Slouka, I. Wiedermannová and P. Bednárˇ
Vol. 40
5-Ethoxy-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-triazin-3(2H)-
one (3).
lected by suction, washed with water and dried. Sample for analy-
sis was prepared by crystallization from anhydrous ethanol. Yield
64.4 mg (96.1 %), mp 265-268 °C; IR: 3394, 3146, 2931, 2854,
Compound 1 (49.1 mg, 0.186 mmol) was dissolved in anhy-
drous ethanol (10 ml) in a sealed vial. After 10 min, quantitative
yield of the product was found (TLC). The solution was evapo-
rated and the resulting oily product mixed with hexane (3 ml).
Solids were collected by filtration, washed with hexane and crys-
tallized from a small amount of ethanol by standing at – 20 °C.
Yield: 46.7 mg (81.1 %), mp 140-144 °C (dec.). IR: 3440, 3194,
1
1648, 1586, 1542, 1451, 1333, 756; H NMR (360 MHz, CDCl ):
3
δ 1.06-1.96 (m, 10H, CH ); 4.07 (bs, 1H, CH); 6.07 (bs, 1H, NH);
2
6.97 (t, 1H, arom., J = 7.6 Hz); 7.25-7.43 (m, 6H, arom.); 7.57-
13
7.60 (m, 2H, arom.); 10.30 (bs, 1H OH); C NMR (300 MHz,
DMSO-d ): δ 25.2, 25.6, 31.6, 49.5, 116.7, 119.3, 119.9, 125.6,
6
127.3, 128.8, 131.7, 131.9, 136.3, 142.3, 153.0, 155.2, 156.2; MS
+
+
(ESI, m/z (rel %)): 385.2 (50) [M+Na] , 363.3 (100) [M+H] .
Anal. Calcd. for C H N O (362.4): C, 69.59; H, 6.12; N,
1
2981, 1656, 1591, 1455, 1427, 1260, 1153, 757. H NMR (360
21 22
4 2
MHz, CDCl ): δ 1.49 (t, 3H, CH , J = 7.0 Hz); 4.66 (q, 2H, CH ,
3
3
2
15.46. Found C, 69.45; H, 5.92; N, 15.54.
J = 7.0 Hz); 6.93-7.01 (m, 2H, arom.); 7.33 (t, 1H, arom., J = 7.6
Hz); 7.40 (d, 1H, arom., J = 7.1 Hz); 7.48 (t, 2H, arom., J = 7.6
Hz); 7.61 (d, 2H, arom., J = 7.2 Hz); 7.99 (d, 1H, arom., J = 7.2
Hz); 9.52 (s, 1H, OH). MS (ESI, m/z (rel %)): 332.2 (100)
6
N -[6-(2-Hydroxyphenyl)-3-oxo-2-phenyl-2,3-dihydro-1,2,4-tri-
azin-5-yl]lysine (4d).
Compound 1 (44.0 mg, 0.167 mmol) was suspended, with stir-
ring, in aqueous solution (5 ml) of DL-lysine (0.334 mmol) pre-
pared from DL-lysine hydrochloride and an equivalent amount of
sodium hydroxide. After 24 h stirring, the obtained solution was
neutralized with dilute acetic acid to pH 7. After 1 h stirring, the
precipitate was collected on filter, washed with water and dried;
Yield 52.4 mg (76.5 %), mp 275 °C (dec.); IR: 3400, 3068, 2936,
+
+
[M+Na] , 310.3 (20) [M+H] .
Anal. Calcd. for C H N O (309.3): C, 66.01; H, 4.89; N,
17 15
3 3
13.58. Found N, 65.78; H, 4.74; N, 13.34.
6-(2-Hydroxyphenyl)-5-imino-2-phenyl-4,5-dihydro-1,2,4-tri-
azin-3(2H)-one (4a).
A mixture of compound 1 (23.5 mg, 0.089 mmol) and 26%
aqueous ammonia (3 ml) was stirred until a solution was obtained
(6 h). The yellow solution was evaporated in vacuo to dryness.
Yield 26.3 mg (99.1 %) of hydrate of 4a. Anhydrous compound
was obtained by crystallization from ethanol and drying at 140
1
1651, 1586, 1546, 1453, 1356, 754; H NMR (360 MHz, DMSO-
d ): δ 1.35-1.81 (m, 6H, CH ); 3.0-3.8 bs (COOH, CH, CH and
6
2
2
NH protons together with residue of water); 6.88 (t, 1H, arom.,
J = 7.4 Hz); 7.01 (d, 1H, arom., J = 7.9 Hz); 7.27-7.34 (m, 3H,
arom.); 7.40-7.46 (m, 2H, arom.); 7.53-7.56 (m, 2H, arom.); OH
proton is missing in spectrum; MS (ESI, m/z (rel %)): 410.3 (100)
°C for 2 h. Mp 235-237 °C. IR: 3474, 3393, 3074, 1673, 1644,
1
1593, 1451, 1338, 1266, 576. H NMR (360 MHz, DMSO-d ): δ
6
+
-
[M+H] ; negative mode: 408.2 (100) [M-H] .
Anal. Calcd. for C H N O (409.4): C, 61.60; H, 5.66; N,
6.87 (bs, 1H, NH); 6.94 (t, 1H, arom., J = 7.4 Hz); 6.98 (d, 1H,
arom., J = 8.2 Hz); 7.31-7.39 (m, 3H, arom.); 7.45-7.49 (m, 2H,
21 23
5 4
17.10. Found C, 61.43; H, 5.79; N, 17.03.
arom.); 7.57-7.60 (m, 2H, arom.); 8.18 (bs, 1H, OH); 10.03 (bs,
13
1H, NH); C NMR (300 MHz, DMSO-d ): δ 117.0, 118.1,
6
5-Anilino-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-triazin-3(2H)-
one (4e).
119.8, 126.5, 129.1, 129.9, 131.3, 132.8, 137.2, 140.1, 141.6,
+
143.7, 156.4; MS (ESI, m/z (rel %)): 303.1 (20) [M+Na] , 281.3
Compound 1 (22.3 mg, 0.085 mmol) was dissolved in aniline
(0.5 ml) with stirring at room temperature. After 20 min, water
(7 ml) was added to the solution and compound 4e was slowly
precipitated under stirring with dilute acetic acid. Sample for
analysis was prepared by crystallization from ethanol; Yield 22.7
mg (75.2 %), mp 245-248 °C; IR: 3365, 3145, 1650, 1549, 1518,
+
(100) [M+H] .
Anal. Calcd. for C H N O (280.3): C, 64.28; H, 4.32; N,
15 12
4 2
19.99. Found C, 63.98; H, 4.05; N, 19.71.
6-(2-Hydroxyphenyl)-5-(methylamino)-2-phenyl-1,2,4-triazin-
3(2H)-one (4b).
1
1449, 1363, 1250, 751, 693; H NMR (360 MHz, DMSO-d ): δ
A mixture of 1 (21.1 mg, 0.080 mmol) and 35% aqueous
methylamine was stirred for 30 min. The obtained solution was
evaporated in vacuo to dryness to yield 27.4 mg (98.3 %) of tri-
hydrate of 4b. Anhydrous compound was obtained by crystalliza-
tion from ethanol and drying at 140 °C for 2 h. Mp 273-275 °C;
IR: 3405, 3337, 3059, 2935, 1653, 1586, 1556, 1453, 1363, 1257,
6
6.93 (d, 1H, arom., J = 7.5 Hz); 7.00 (d, 1 H, arom., J = 8.4 Hz);
7.18 (t, 1H, arom., J = 7.4 Hz); 7.33-7.47 (m, 7H, arom.); 7.57
(m, 2H, arom.); 6.67 (d, 2H, arom., J = 7.7 Hz); 9.01 (s, 1H, OH);
10.13 (bs, 1H, NH); MS (ESI, m/z (rel %)): 379.2 (100)
+
+
[M+Na] , 357.4 (40) [M+H] .
1
Anal. Calcd. for C H N O (356.4): C, 70.77; H, 4.53; N,
747; H NMR (360 MHz, DMSO-d ): δ 2.86 (s, 3H, CH ); 6.94
21 16
4 2
6
3
15.72. Found C, 71.00; H, 4.42; N, 15.54.
(t, 1H, arom., J = 7.4 Hz); 6.99 (d, 1H, arom., J = 8.2 Hz); 7.31-
7.39 (m, 3H, arom.); 7.45-7.49 (m, 2H, arom.); 7.50-7.56 (bs, 1H,
NH); 7.56-7.59 (m, 2H, arom.); 9.90 (bs, 1H, OH); MS (ESI, m/z
5-(Diethylamino)-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-triazin-
3(2H)-one (4f).
+
+
(rel %)): 317.2 (70) [M+Na] , 295.3 (100) [M+H] .
Anal. Calcd. for C H N O (294.3): C, 65.30; H, 4.79; H, N
This compound was prepared in a similar way as compound 4e
using compound 1 (47.1 mg, 0.179 mmol) and diethylamine (0.5
ml); Yield 56.2 mg (93.3 %), mp 216-219 °C (dec.); IR: 3445,
16 14
4 2
19.04. Found C, 65.12; H, 4.76; N, 18.79.
5-(Cyclohexylamino)-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-tri-
azin-3(2H)-one (4c).
3087, 2986, 2939, 1632, 1568, 1519, 1431, 1352, 1262, 1140,
1
755; H NMR (360 MHz, DMSO-d ): δ 0.98 (bs, 6H, CH ); 3.32
6
3
(bs, 4H, CH ); 6.88-6.93 (m, 2H, arom.); 7.27-7.44 (m, 5H,
arom.); 7.52-7.55 (m, 2H, arom.); 10.03 (bs, 1H, OH); C NMR
Compound 1 (48.7 mg, 0.185 mmol) was dissolved in cyclo-
hexylamine (0.5 ml) at room temperature. After 30 min with occa-
sional stirring, the solid began to precipitate from the solution.
The mixture was diluted with water (4 ml) and neutralized with
dilute acetic acid to pH ~ 8. The precipitate compound was col-
2
13
(300 MHz, DMSO-d ): δ 13.1, 43.5, 115.9, 119.9, 124.7, 125.1,
6
127.3, 128.9, 130.4, 131.1, 134.5, 142.0, 152.2, 155.3, 156.2; MS
+
+
(ESI, m/z (rel %)): 359.2 (100) [M+Na] , 337.4 (35) [M+H] .

Sep-Oct 2003
Utilization of Cleavage of the [1]Benzofuro[2,3-e][1,2,4]triazine Ring
809
Anal. Calcd. for C H N O (336.4): C, 67.84; H, 5.99; N,
16.66. Found C, 67.59; H, 5.88; N, 16.49.
°C (dec.); IR: 3404, 3065, 2941, 1649, 1586, 1551, 1452, 1353,
19 20
4 2
1
755; H NMR (360 MHz, DMSO-d ): δ 1.64 (bs, 4H, CH ); 3.3-
6
2
4.1 (bs, 2x CH and NH together with residue of water); 6.94 (t,
2
6-(2-Hydroxyphenyl)-2-phenyl-5-piperidino-1,2,4-triazin-
3(2H)-one (4g).
2H, arom., J = 7.4 Hz); 7.00 (d, 2H, arom., J = 8.5 Hz); 7.31-7.39
(m, 6H, arom.); 7.45-7.49 (m, 4H, arom); 7.57-7.60 (m, 4H,
arom.); OH protons are missing in spectrum; MS (ESI, m/z (rel
This compound was prepared in a similar way as compound 4e
using compound 1 (50.9 mg, 0.193 mmol) and piperidine (0.5
ml); Yield 64.1 mg (95.1 %); mp 222-225 °C (dec.); IR: 3325,
+
+
%)): 637.2 (65) [M+Na] , 615.3 (100) [M+H] .
Anal. Calcd. for C H N O (614.7): C, 66.44; H, 4.92; N,
34 30
8 4
1
3063, 2946, 1635, 1558, 1507, 1448, 1340, 753; H NMR (360
18.23. Found C, 66.81; H, 4.88; N, 18.07.
MHz, DMSO-d ): δ 1.44 (bs, 4H, CH ); 1.53 (q, 2H, CH , J = 5.3
6
2
2
1,5,10-Tris[6-(2-hydroxyphenyl)-3-oxo-2-phenyl-1,2,4-triazin-
5-yl]-1,5,10-triazadecane (4k).
Hz); 3.47 (bs, 4H, CH ); 6.90-6.94 (m, 2H, arom.); 7.28-7.36 (m,
2
3H, arom.); 7.41-7.45 (m, 2H, arom.); 7.54-7.56 (m, 2H, arom.);
Compound 1 (50.2 mg, 0.191 mmol) was dissolved in a solu-
tion of spermidine (9.23 mg, 0.063 mmol) in anhydrous chloro-
form (3.0 ml). The solution was heated at 50 °C in a sealed 5-ml
glass vial for 18 hrs and then evaporated to dryness. Sample for
analysis was prepared by crystallization from DMSO; Yield 57.3
10.10 (bs, 1H, OH); MS (ESI, m/z (rel %)): 371.3 (100)
+
+
[M+Na] , 349.4 (25) [M+H] .
Anal. Calcd. for C H N O (348.4): C, 68.95; H, 5.79; N,
20 20
4 2
16.08. Found C, 68.86; H, 5.64; N, 15.79.
5-[(2-Aminoethyl)amino]-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-
triazin-3(2H)-one (4h).
mg (96.3 %), mp 196-201 °C (dec.); IR: 3402, 3069, 2945, 1648,
1
1586, 1559, 1451, 1353, 756; H NMR (360 MHz, DMSO-d ): δ
6
This compound was prepared in a similar way as compound 4e
using compound 1 (70.0 mg, 0.266 mmol) and ethylenediamine
(0.5 ml); Yield 60.1 mg (69.9 %), mp 260-270 °C (dec.); IR:
1.60-1.73 (m, 6H, CH ); 3.1-4.0 (bs, 4x CH and NH together
2 2
with residue of water); 6.87-7.00 (m, 4H, arom.); 7.03-7.12 (m,
5H, arom.); 7.15-7.20 (m, 6H, arom.); 7.31-7.42 (m, 8H, arom.);
7.44-7.52 (m, 4H, arom.); OH protons are missing in spectrum;
1
3309, 2960, 1665, 1548, 1453, 1340, 756; H NMR (360 MHz,
+
DMSO-d ): δ 2.81 (t, 2H, CH , J = 6.2 Hz); 3.44 (t, 2H, CH , J =
MS (ESI, m/z): 935.3 (100) [M+H] .
6
2
2
6.2 Hz); 3.6-4.5 (bs, NH together with residue of water); 6.88 (t,
1H, arom. J = 7.4 Hz); 6.95 (d, 1H, arom., J = 8.5 Hz); 7.32-7.38
(m, 3H, arom.); 7.45-7.50 (m, 2H, arom.); 7.56-7.60 (m, 2H,
arom.); OH proton is missing in spectrum; MS (ESI, m/z (rel %)):
Anal. Calcd. for C H N O (935.0): C, 66.80; H, 4.96; N,
17.98. Found C, 66.53; H, 4.78; N, 17.71.
52 46 12 6
5-Hydrazino-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-triazin-3(2H)-
one (5a).
+
324.3 (80) [M+H] .
Compound 1 (318.2 mg, 1.209 mmol) was dissolved in 80%
hydrazine hydrate (5.0 ml). After 1 h stirring at room tempera-
ture, the solution was diluted with water (10 ml) and neutralized
with dilute acetic acid. The precipitated solid was collected on a
filter and washed with water. Sample for analysis was prepared
by crystallization from anhydrous ethanol; Yield 345.9 mg (96.9
%), mp 235-240 °C (dec.); IR: 3346, 3241, 3162, 3073, 1693,
Anal. Calcd. for C H N O (323.4): C, 63.15; H, 5.30; N,
21.66. Found C, 62.99; H, 5.66; N, 21.25.
17 17
5 2
5-[(4-Aminobutyl)amino]-6-(2-hydroxyphenyl)-2-phenyl-1,2,4-
triazin-3(2H)-one (4i).
Compound 1 (57.4 mg, 0.218 mmol) was dissolved in a solu-
tion of butane-1,4-diamine (111.8 mg, 1.268 mmol) in chloro-
form (9 ml). After 18 h stirring, the precipitated solid was col-
lected by filtration, washed with chloroform (2 x 2 ml) and dried.
This product was suspended in chloroform (5 ml) (to remove
traces of butane-1,4-diamine) and after 30 min stirring it was
again collected by filtration and dried. Sample for analysis was
prepared the crystallization from DMSO; Yield 60.3 mg (78.8
1
1661, 1584, 1455, 1337, 755; H NMR (360 MHz, DMSO-d ): δ
6
5.50-6.50 (bs, 3H, NH); 6.77-6.83 (m, 2H, arom.); 7.18-7.21 (m,
2H, arom.); 7.27 (t, 1H, arom., J = 7.4 Hz); 7.40 (m, 2H, arom.);
7.50 (m, 2H, arom.); 9.48 (bs, 1H, OH); MS (ESI, m/z (rel %)):
+
296.4 (70) [M+H] .
Anal. Calcd. for C H N O (295.3): C, 61.01; H, 4.44; N,
15 13
5 2
23.72. Found C, 60.74; H, 4.32; N, 23.56.
%), mp 220 °C (dec.); IR: 3353, 3064, 2946, 1652, 1554, 1452,
1
1154, 756; H NMR (360 MHz, DMSO-d ): δ 1.46-1.69 (m, 4H,
6
6-(2-Hydroxyphenyl)-2-phenyl-5-(phenylhydrazino)-1,2,4-tri-
azin-3(2H)-one (5b).
CH ); 2.66 (t, 2H, CH , J = 7.0 Hz); 3.34 (t, 2H, CH , J = 6.8
2
2
2
Hz); 3.4-4.2 (bs, NH together with residue of water) 6.76 (t, 1H,
arom., J = 7.4 Hz); 6.84 (d, 1H, arom., J = 8.5 Hz); 7.26-7.33 (m,
3H, arom.); 7.40-7.45 (m, 2H, arom.); 7.53-7.58 (m, 2H, arom.);
OH proton is missing in spectrum; MS (ESI, m/z (rel %)): 352.3
Compound 1 (45.0 mg, 0.171 mmol) was suspended in phenyl-
hydrazine (0.5 ml) at room temperature. After 4 h stirring, water (4
ml) was added to the bright yellow suspension, which was then neu-
tralized with dilute acetic acid, then collected by filtration, washed
with water and crystallized for analysis from acetic acid – DMSO
(3:1 v/v) mixture; Yield 60.1 mg (94.5 %), mp 277-280 °C; IR:
+
(70) [M+H] .
Anal. Calcd. for C H N O (351.4): C, 64.94; H, 6.02; N,
19 21
5 2
19.93. Found C, 64.68; H, 6.32; N, 19.79.
1
3345, 3342, 3062, 1696, 1601, 1501, 1362, 1244, 470; H NMR
/
5,5 -[(Butane-1,4-diyl)diamino]bis[6-(2-hydroxyphenyl)-2-
(360 MHz, DMSO-d ): δ 6.71 (t, 1H, arom., J = 7.3 Hz); 6.79 (d,
6
phenyl-1,2,4-triazin-3(2H)-one] (4j).
2H, arom., J = 7.7 Hz); 6.87 (t, 1H, arom., J = 7.4 Hz); 6.92 (d, 1H,
arom., J = 8.0 Hz); 7.14 (t, 2H, arom., J = 8.0 Hz); 7.25-7.35 (m,
3H, arom.); 7.40-7.44 (m, 2H, arom.); 7.54-7.57 (m, 2H, arom.);
9.15 (s, 1H, NH); 9.49 (s, 1H, NH); 10.56 (bs, 1H, OH); MS (ESI,
Compound 1 (40.3 mg, 0.153 mmol) was dissolved in a solu-
tion of butane-1,4-diamine (6.21 mg, 0.070 mmol) in anhydrous
chloroform (2.5 ml). After 18 h stirring in a sealed 5-ml glass
vial, the precipitate was collected by filtration and washed with
choroform (2 x 0.5 ml). Sample for analysis was prepared by
crystallization from DMSO; Yield 41.6 mg (96.1 %), mp 300-305
+
+
m/z (rel %)): 394.2 (60) [M+Na] , 372.3 (40) [M+H] .
Anal. Calcd. for C H N O (371.4): C, 67.91; H, 4.61; N,
21 17
5 2
18.86. Found C, 68.05; H, 4.51; N, 18.54.

810
J. Sty´skala, J. Slouka, I. Wiedermannová and P. Bednárˇ
Vol. 40
2-[6-(2-Hydroxyphenyl)-3-oxo-2-phenyl-2,3-dihydro-1,2,4-tri-
and crystallized from ethanol. Yield 68.1 mg (91.8 %), mp 293-296
azin-5-yl]hydrazinecarboxamide (5c).
°C; IR: 3505, 3140, 3076, 2906, 1746, 1490, 1314, 1252, 1157,
1
631; H NMR (360 MHz, DMSO-d ): δ 6.96-7.00 (m, 2H, arom.);
6
A mixture of 1 (108.8 mg, 0.411 mmol), semicarbazide
hydrochloride (1276.0 mg, 11.44 mmol) and solution of sodium
hydroxide (458.0 mg, 11.44 mmol) in water (6 ml) was stirred for
24 h. A pale yellow solid was collected by filtration and washed
with water; Yield 146.0 mg (99.8 %) of hydrate of 5c, mp 200-210
°C (with formation of 6d). Sample for analysis was prepared by
crystallization from ethanol and dried at 115 °C for 1 h; IR: 3471,
7.40 (t, 1H, arom., J = 8.2 Hz); 7.48 (t, 1H, arom.); 7.53-7.59 (m,
3H, arom.); 7.62-7.65 (m, 2H, arom.); 9.86 (s, 1H, OH); 14.71 (bs,
13
1H, NH); C NMR (300 MHz, DMSO-d ): δ 116.9, 117.7, 119.4,
6
126.5, 128.6, 129.3, 130.9, 132.2, 138.1, 140.5, 141.3, 142.6,
+
143.2, 156.1; MS (ESI, m/z (rel %)): 360.3 (100) [M+Na] , 338.3
+
-
(30) [M+H] ; negative mode: 336.1 (100) [M-H] .
Anal. Calcd. for C H N O S (337.4): C, 56.96; H, 3.29; N,
1
16 11 5 2
3270, 1723, 1680, 1572, 1487, 1335, 1123,755; H NMR (360
20.76. Found C, 56.83; H, 3.60; N, 20.52.
MHz, DMSO-d ): δ 5.50-6.50 (bs, 2H, NH); 6.87-6.93 (m, 2H,
6
arom.); 7.27-7.34 (m, 3H, arom.); 7.45-7.49 (m, 2H, arom.); 7.56-
8-(2-Hydroxyphenyl)-6-phenyl[1,2,4]triazolo[4,3-d][1,2,4]tri-
azine-3,5(2H,6H)-dione (6d).
7.60 (m, 2H, arom.); 9.26 (s, 1H, NH); 9.62 (bs, 1H, NH); 10.79
13
(bs, 1H, OH); C NMR (300 MHz, DMSO-d ): δ 116.3, 119.1,
6
Hydrate of 5c (14.93 mg, 0.042 mmol) was heated at 200 °C in
a weighed glass vial for 30 min and the resulting melt was crys-
tallized from ethanol (10 ml); Yield 13.4 mg (99.5 %), mp 345-
120.9, 125.5, 127.3, 128.9, 129.4, 130.9, 131.2, 141.0, 144.2,
+
147.2, 155.9, 156.8; MS (ESI, m/z (rel %)): 361.2 (30) [M+Na] ,
+
-
339.3 (100) [M+H] ; negative mode: 337.2 (100) [M-H] .
Anal. Calcd. for C H N O (338.3): C, 56.80; H, 4.17; N,
347 °C (dec.); IR: 3144, 3067, 1772, 1685, 1492, 1334, 1298,
16 14
6 3
1
768; H NMR (360 MHz, DMSO-d ): δ 6.95-7.00 (m, 2H,
6
24.84. Found C, 56.72; H, 4.23; N, 24.70.
arom.); 7.40 (t, 1H, arom., J = 8.5 Hz); 7.46 (t, 1H, arom., J = 7.0
Hz); 7.53-7.58 (m, 2H, arom.); 7.61-7.63 (m, 3H, arom.); 9.93
(bs, 1H, OH); 12.90 (bs, 1H, NH); MS (ESI, m/z (rel %)): 322.3
8-(2-Hydroxyphenyl)-6-phenyl[1,2,4]triazolo[4,3-d][1,2,4]tri-
azin-5(6H)-one (6a).
+
-
(20) [M+H] , negative mode: 320.2 (100) [M-H] .
Anal. Calcd. for C H N O (321.3): C, 59.81; H, 3.45; N,
A solution of compound 5a (60.0 mg, 0.203 mmol) in formic
acid (2 ml) was refluxed for 75 min. Upon cooling, the solution
was diluted with water (10 ml) and the precipitate was collected
on a filter and washed with water. Sample for analysis was pre-
pared by crystallization from methanol (1 ml per 8 mg); Yield
56.2 mg (90.6 %), mp 240-242 °C; IR: 3445, 3144, 3097, 1728,
16 11
5 3
21.80. Found C, 59.81; 3.45; N, 20.60.
8-(2-Hydroxyphenyl)-6-phenyltetrazolo[1,5-d][1,2,4]triazin-
5(6H)-one (7).
Compound 5a (50.0 mg, 0.169 mmol) was dissolved in solu-
tion of 35% hydrochloric acid (0.2 ml) and water (15 ml) at 60-
70 °C and then cooled to 0-5 °C. To this mixture, a solution of
sodium nitrite (11.68 mg, 0.169 mmol) in water (2 ml) was
added. After 3 h stirring at 0-5 °C, the precipitate was collected
by filtration and washed with water. Sample for analysis was
prepared by crystallization from methanol (1 ml per 1 mg); Yield
1
1494, 1467, 1363, 1281, 1179, 778, 680; H NMR (360 MHz,
DMSO-d ): δ 7.03-7.08 (m, 2H, arom.); 7.46 (t, 1H, arom., J =
6
8.0 Hz); 7.51 (t, 1H, arom., J = 7.2 Hz); 7.59-7.66 (m, 2H,
arom.); 7.71-7.76 (m, 2H, arom.); 7.94 (d, 1H, arom., J = 8.0 Hz);
9.77 (s, 1H, arom.); 10.15 (bs, 1H, OH); MS (ESI, m/z (rel %)):
+
306.3 (50) [M+H] .
Anal. Calcd. for C H N O (305.3): C, 62.95; H, 3.63; N,
16 11
5 2
45.5 mg (87.7 %), mp 222-225 °C (dec.); IR: 3450, 3175, 1761,
22.94. Found C, 62.76; H, 3.25; N, 22.79.
1
1748, 1463, 1217, 773, 709; H NMR (360 MHz, DMSO-d ): δ
6
2-(3-Methyl-5-oxo-6-phenyl-5,6-dihydro[1,2,4]triazolo[4,3-
d][1,2,4]triazin-8-yl)phenyl acetate (6b).
7.04-7.10 (m, 2H, arom.); 7.49 (t, 1H, arom., J = 8.3 Hz); 7.57-
7.71 (m, 4H, arom.); 7.76-7.78 (m, 2H, arom.); 10.18 (s, 1H,
13
OH); C NMR (300 MHz, DMSO-d ): δ 117.0, 118.1, 119.8,
A mixture of 5a (74.1 mg, 0.251 mmol) and acetic anhydride
(0.75 ml) in anhydrous pyridine (2 ml) was heated on a boiling
water bath for 1 h. Upon cooling to 2 °C, the solution was diluted
with water to 40 ml. The precipitate was collected by filtration,
washed with water and (for analysis) crystallized from an
ethanol-water mixture; Yield 71.2 mg (78.5 %), mp 154-155 °C;
6
126.5, 129.5, 129.6, 131.3, 132.8, 137.2, 140.1, 141.6, 143.3,
+
156.4; MS (ESI, m/z (rel %)): 307.1 (100) [M+H] .
Anal. Calcd. for C H N O (306.3): C, 58.82; H, 3,29; N,
15 10
6 2
27.44. Found C, 58.89; H, 3.20; N, 27.29.
6-(2-Hydroxyphenyl)-2-phenyl-5-thioxo-4,5-dihydro-1,2,4-tri-
azin-3(2H)-one (8).
1
IR: 3073, 1746, 1728, 1488, 1334, 1196, 913, 773; H NMR (360
MHz, DMSO-d ): δ 1.91 (s, 3H, COCH ); 2.91 (s, 3H, CH );
6
3
3
Compound 1 (84.0 mg, 0.319 mmol) was suspended in a solu-
tion of NaOH (ca. 400 mg of NaOH in 5 ml of water) saturated
7,37 (d, 1H, arom., J = 8.1 Hz); 7.50-7.54 (m, 2H, arom.); 7.58-
7.63 (m, 2H, arom.); 7.65-7.71 (m, 3H, (arom.); 8.12 (d, 1H,
+
with H S at room temperature. The mixture was stirred for 3 h at
arom., J = 7.9 Hz); MS (ESI, m/z (rel %)): 384.2 (45) [M+Na] ,
2
+
room temperature to obtain a solution. After 18 h, the solution was
diluted with water (10 ml) and carefully neutralized with dilute
acetic acid to pH 7-8. The precipitate was collected on filter and
washed with water. Sample for analysis was obtained by crystal-
lization from a heptane-toluene mixture; Yield 40.0 mg (42.1 %),
mp 157-160 °C (dec.); IR: 3031, 1725, 1694, 1605, 1487, 1454,
362.1 (35) [M+H] .
Anal. Calcd. for C H N O (361.4): C, 63.15; H, 4.18; N,
19 15
5 3
19.38. Found C, 62.98; H, 4.25; N 19.35.
8-(2-Hydroxyphenyl)-6-phenyl-3-thioxo-2,3-dihydro[1,2,4]tria-
zolo[4,3-d][1,2,4]triazin-5(6H)-one (6c).
1
1319, 762; H NMR (360 MHz, DMSO-d ): δ 6.84-6.90 (m, 2H,
A mixture of 5a (64.9 mg, 0.219 mmol) and carbon disulfide
(0.2 ml) in pyridine (3 ml) was stirred in a sealed glass vial at room
temperature. After 18 h, the vial was heated on a water bath (70 °C)
for 10 min and evaporated to dryness in vacuo. The residue was
mixed with water (5 ml), collected on a filter, washed with water
6
arom.); 7.22 (d, 1H, arom., J = 7.5 Hz); 7.27 (t, 1H, arom., J = 7.3
Hz); 7.44 (t, 1H, arom., J = 7.2 Hz); 7.50-7.55 (m, 2H, arom.);
7.60-7.66 (m, 2H, arom.); 9.48 (s, 1H, OH); 13.81 (bs, 1H, NH);
-
MS (ESI, m/z (rel %)): negative mode: 296.4 (100) [M-H] .

Sep-Oct 2003
Utilization of Cleavage of the [1]Benzofuro[2,3-e][1,2,4]triazine Ring
811
Anal. Calcd. for C H N O S (297.3): C, 60.59; H, 3.73; N,
14.13. Found C, 60.33; H, 3.45; N, 14.42.
grant of the Ministry of Education, Youth and Sports No CEZ:
MSM 153100008. Biological activity was tested in Laboratory of
Growth Regulators, Institute of Experimental Botany, ASCR and
Palacky´ University.
15 11
3 2
6-(2-Hydroxyphenyl)-2-phenyl-4,5-dihydro-1,2,4-triazin-3(2H)-
one (9).
A mixture of a solution of NaOH (ca. 200 mg of NaOH in 3.5
ml of water) saturated with hydrogen selenide (prepared from
MgSe and dilute HCl in a stream of nitrogen) and compound 1
(97.1 mg, 0.369 mmol) in a sealed glass vial under nitrogen was
stirred for 12 h at room temperature. The content of the vial was
diluted with water (5 ml) and carefully neutralized with dilute
acetic acid to pH 7-8. The precipitate was collected on filter and
washed with water. The dry product was suspended in chloro-
form (5 ml) allowed to stand overnight (red Se changed to metal-
lic Se) and collected by filtration. Purification by elution with
chloroform through a short column (4 cm i.d.) filled with silica
gel 60 (230-400 mesh, 40 g) gave 9. Sample for analysis was pre-
pared by crystallization from heptane-toluene-methanol mixture
(2:1:0.1 v/v/v); Yield 37.5 mg (38.0 %), mp 137-140 °C (dec.);
REFERENCES AND NOTES
[1] Part I in the series "The Cleavage of Heterocyclic
Compounds in Organic Synthesis".
[2] A. M. Gold, J. Org. Chem., 26, 3991 (1961).
[3] D. Starr and R. M. Hixon, Org. Synth. Coll. Vol. II, 571
(1943).
[4] H. Stone and H. Shechter, Org. Synth. Coll. Vol. IV, 321
(1963).
[5] K. Hafner and K. P. Meinhardt, Org. Synth. Coll. Vol. VII,
15 (1990).
[6] P. Baumgarten, Ber. Dtsch. Chem. Ges., 59, 1166 (1926).
[7] G. W. Fisher, Ber. Dtsch. Chem. Ges., 103, 3489 (1970).
[8] R. Koenig, Ber. Dtsch. Chem. Ges., 63, 2823 (1930).
[9] J. Sty´skala, J. Slouka, M. Hejsek and V. Bekárek, Collect.
Czech. Chem. Commun., 62, 1754 (1997).
[10] J. Sty´skala and J. Slouka, Acta Univ. Palacki. Olomuc.,
Fac. Rerum Nat., Chemica, 37, 73 (1998); Chem. Abstr., 131,
102259 (1999).
1
IR: 2928, 1665, 1497, 1466, 1256, 1197, 695; H NMR (360
MHz, CDCl ): δ 3.38 (s, 2H, CH ); 5,81 (s, 1H, NH); 6,90 (t, 1H,
3
2
arom., J = 8.2 Hz); 6,97 (d, 1H, arom., J = 8.2 Hz); 7,29-7,57 (m,
7H, arom.); 11,02 (bs, 1H, OH); MS (ESI, m/z (rel %)): negative
-
mode: 266.3 (100) [M-H] .
Anal. Calcd. for C H N O (267.3): C, 67.40; H, 4.90; N,
15 13
3 2
15.72. Found C, 67.52; H, 4.86; N, 15.88.
[11] J. Sty´skala and J. Slouka, Heterocycl. Commun., 5, 349
(1999).
Acknowledgement.
ˇ
[12] Z. Trávnícˇek, M. Malonˇ, Z. Sindelárˇ, K. Dolezˇal, J. Rolcˇík,
This research was supported by Postdoc grant No.
204/01/P117 of Grant agency of the Czech Republic and by the
V. Krysˇtov, M. Strnad and J. Marek, J. Inorg. Biochem., 84, 23
(2001).