4-(2-Hydroxyaryl)-1,2,3-selenadiazoles as precursors of benzofuran-2-selenolates

Article abstract of DOI:10.1023/A:1013832925639

The reaction of selenium dioxide with o-hydroxyacetophenone semicarbazones gives 4-(2-hydroxyaryl)-1,2,3-selenadiazoles which undergo ready decomposition by the action of potassium carbonate to form benzofuran-2-selenolates. The latter can be alkylated with methyl iodide and benzyl chloride and arylated with 2,4-dinitrochlorobenzene. Intermediate formation of 2-(o-hydroxyphenyl)ethyneselenolate during decomposition of 1,2,3-selenadiazoles was proved by the isolation of methyl o-methoxyphenylethynyl selenide when the substrate was treated with potassium carbonate in the presence of methyl iodide.

Full text of DOI:10.1023/A:1013832925639

Russian Journal of Organic Chemistry, Vol. 37, No. 11, 2001, pp. 1643 1648. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 11, 2001,
pp. 1713 1718.
Original Russian Text Copyright
2001 by Petrov, Abramov, Abramova, Dehaen, Lyakhovetskii.
4-(2-Hydroxyaryl)-1,2,3-selenadiazoles as Precursors
of Benzofuran-2-selenolates*
M. L. Petrov, M. A. Abramov, I. P. Abramova, W. Dehaen, and Yu. I. Lyakhovetskii
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 198013 Russia
e-mail: mlpetrov@tu.spb.ru
Received December 28, 2000
Abstract The reaction of selenium dioxide with o-hydroxyacetophenone semicarbazones gives 4-(2-hydroxy-
aryl)-1,2,3-selenadiazoles which undergo ready decomposition by the action of potassium carbonate to form
benzofuran-2-selenolates. The latter can be alkylated with methyl iodide and benzyl chloride and arylated
with 2,4-dinitrochlorobenzene. Intermediate formation of 2-(o-hydroxyphenyl)ethyneselenolate during decom-
position of 1,2,3-selenadiazoles was proved by the isolation of methyl o-methoxyphenylethynyl selenide when
the substrate was treated with potassium carbonate in the presence of methyl iodide.
4-Substituted 1,2,3-selenadiazoles are known [1]
to readily decompose by the action of strong bases,
such as potassium ethoxide, butyllithium, etc., with
liberation of nitrogen and formation of alkyneseleno-
lates. The latter are widely used in organic synthesis
for preparation of acetylenic selenides, in 1,3-anionic
cycloadditions and other cyclization reactions, and for
generation of highly reactive selenoketenes [2 7]:
ring. Compounds IIa IIc were prepared by the known
method [10], by the action of selenium dioxide in
acetic acid on hydrazones derived from 2-hydroxy-
acetophenone (Ia), 2-hydroxy-4-methylacetophenone
(Ib), and 2-hydroxy-5-methylacetophenone (Ic):
I, II, R = R = H (a); R = Me, R = H (b); R = H, R = Me (c).
The structure of 4-(2-hydroxyaryl)-1,2,3-selenadi-
azoles IIa IIc was confirmed by the IR, H and 13C
NMR, and mass spectra. In the IR spectrum of IIa
1
We recently reported a new convenient procedure
for synthesizing previously unknown 2-benzylseleno-
benzofuran via decomposition of readily accessible
4-(2-hydroxyphenyl)-1,2,3-selenadiazole [8, 9]. The
present communication describes in detail the syn-
thesis of 4-(2-hydroxyaryl)-1,2,3-selenadiazoles and
their transformation into benzofuran-2-selenolates.
With a view to obtain new derivatives of acetylenic
selenolates having one more reactive functionality,
a hydroxy group, we synthesized 4-(2-hydroxy-
phenyl)-1,2,3-selenadiazole (IIa) and its analogs
IIb and IIc containing a methyl group in the benzene
____________
stretching vibrations of the O H group appear as
1
a broad band at 3336 cm , in keeping with published
data [11]. Both positions and multiplicities of signals
1
in the H and 13C NMR spectra of selenadiazoles
IIa IIc are analogous to those observed in the spectra
of 4-(2-hydroxyphenyl)-1,2,3-thiadiazole [12, 13].
As a result of replacement of the sulfur atom by
a heavy selenium atom, the signal from proton in
position 5 of the selenadiazole ring is located in
a weaker field, 10.09 (IIa), 9.4 (IIb), and 9.52 ppm
(IIc), as a singlet with satellites due to coupling with
77Se (J = 40 42 Hz). The corresponding signal of
4-(2-hydroxyphenyl)-1,2,3-thiadiazole is observed at
8.82 ppm [13]. Likewise, the chemical shift of C5 in
*
This study was financially supported by the Russian Founda-
tion for Basic Research (project no. 00-03-32740).
1070-4280/01/3711-1643$25.00 2001 MAIK Nauka/Interperiodica

1644
PETROV et al.
Scheme 1.
VIII, R2 = Me, Hlg = I (a); R2 = PhCH2, Hlg = Cl (b).
77Se
selenadiazole IIa is
142.1 ppm (JC,
= 133 Hz)
cular ring closure involving the hydroxy group and
selenoketene fragment (Scheme 1).
against 131.4 ppm fCor C5 of 4-(2-hydroxyphenyl)-
1,2,3-thiadiazole [13].
When the reaction was performed in the presence
of benzyl chloride, we obtained 2-benzylselenobenzo-
furan (VIIIb) in good yield. The intermediate forma-
tion of o-hydroxyphenylethyneselenolate (Va) during
decomposition of selenodiazole IIa was proved by
carrying out the reaction in the presence of methyl
iodide. As a result, we isolated 33% of o-methoxy-
phenylethynyl methyl selenide (X) and a small
amount of 2-methylselenobenzofuran (VIIIa). When
methyl iodide was added after preliminary decomposi-
tion of selenadiazole IIa with potassium carbonate
for at least 30 min, the product was 2-methylseleno-
benzofuran (VIIIa) (yield 76%; Scheme 2).
The mass spectra of compounds IIa IIc contained
the molecular ion peaks whose isotope compositions
were consistent with the calculated ones. Further
fragmentation of the molecular ions supports the
assumed structure of selenadiazoles IIa IIc. The
main fragmentation pathway involves successive
elimination of nitrogen molecule and selenium atom.
A similar pattern is typical of photoinduced or thermal
decomposition of these compounds [14].
While trying to alkylate 4-(2-hydroxyphenyl)-1,2,3-
selenadiazole (IIa) at the hydroxy group, we have
found that even such a weak base as potassium
carbonate promotes decomposition of the substrate
(Scheme 1). The product was not the corresponding
alkyneselenolate but benzofuran-2-selenolate (VIIa)
which is reponsible for intense color of the solution.
The process is likely to include several stages: forma-
tion of phenoxide ion III, intramolecular proton
migration with transfer of the negative charge to the
heteroring, elimination of nitrogen molecule to give
alkyneselenolate Va, intramolecular proton transfer
with formation of selenoketene VIa, and intramole-
The structure of alkylation products VIIIa, VIIIb,
1
and X was confirmed by the H and 13C NMR and
mass spectra. The NMR spectra of VIIIa and VIIIb
resemble those obtained for 2-alkylthiobenzofurans
[13]. In the mass spectra of VIIIa and VIIIb we
observed the molecular ion peaks with the expected
isotope compositions. The main fragmentation pattern
3
includes cleavage of the weakest Csp Se bond,
i.e., successive loss of the alkyl substituent, carbon(II)
oxide molecule, and selenium atom. Elimination of
Scheme 2.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

4-(2-HYDROXYARYL)-1,2,3-SELENADIAZOLES AS PRECURSORS OF . . .
1645
Scheme 3.
the alkylseleno group occurs to a minor extent. The
We tried to study the mechanism of decomposition
IR spectrum of o-methoxyphenylethynyl methyl sele-
of 4-(2-hydroxyphenyl)-1,2,3-selenadiazole (IIa) in
1
1
nide (X) contained an absorption band at 2150 cm ,
the presence of Bu4NOH as a base by H NMR
belonging to stretching vibrations of the triple bond
[15]. Selenide X showed in the H NMR spectrum
spectroscopy. Even after 5 min, only signals corre-
sponding to benzofuran-2-selenolate (VIIa) were
observed in the spectrum.
1
signals from aromatic protons and singlets from the
OCH3 and SeCH3 groups at 3.87 and 2.38 ppm,
respectively. The corresponding carbon signals in
EXPERIMENTAL
the 13C NMR spectrum were observed at
55.7
C
(OCH3) and 9.93 ppm (SeCH3); also, signals from
the acetylenic carbon atoms were present at 75.0
The melting points were determined on a Boetius
device. The IR spectra were recorded on an IKS-29
spectrometer. The 1H and 13C NMR spectra were
obtained on Bruker Avance (300 and 75 MHz, respec-
tively) and Bruker AMX-400 (400 and 100 MHz)
instruments using solvent signals as reference. The
mass spectra were run on a Kratos MS-890 high-
resolution mass spectrometer with direct admission
of samples into the ion source; energy of ionizing
electrons 70 eV; ion source temperature 200 C. The
m/z values are given for the major 80Se isotope.
The progress of reactions was monitored by TLC on
Silufol UV-254 plates; spots were visualized by UV
light and iodine vapor. All solvents were dried and
purified by standard procedures.
4-(2-Hydroxyphenyl)-1,2,3-selenadiazole (IIa).
A mixture of 7.7 g (40 mmol) of 2-hydroxyaceto-
phenone semicarbazone (Ia), 15 ml of glacial acetic
acid, and 4.6 g (42 mmol) of powdered selenium
dioxide was stirred for 4 5 h at 60 70 C with protec-
tion from light until gaseous products no longer
evolved. The mixture was cooled to 20 25 C and
filtered from the precipitated selenium, 50 ml of water
C
(C CSe) and 94.3 ppm (C CSe) [16]. Fragmentation
of the molecular ion of X includes elimination of the
methylseleno group with formation of o-methoxy-
phenylethynyl ion. The minor fragmentation pathway
includes successive loss of one methyl group, carbon
monoxide molecule, and the second methyl group.
The arylation of 4-(2-hydroxyaryl)-1,2,3-selenadi-
azoles IIa IIc with 2,4-dinitrochlorobenzene in the
presence of potassium carbonate shows the same
general relations as does the alkylation. As a result,
2-(2,4-dinitrophenylseleno)benzofurans XIa XIc were
isolated in moderate yields (Scheme 3). The NMR
spectral patterns of products XIa XIc were analogous
to those found for alkylseleno derivatives VIIIa and
VIIIb and 2,4-dinitrotoluene [17]. Scheme 4 shows
fragmentation pathways of the molecular ion of XIa
as an example. Judging by the fragment ion peak
intensities, the most probable is elimination of the
4-nitro-2-nitrosophenylseleno moiety. Analogous
mass spectra were obtained for 2-(2,4-dinitrophenyl-
seleno)benzofurans XIb and XIc.
Scheme 4.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

1646
PETROV et al.
was added to the filtrate, and the precipitate was
filtered off and dried. Yield of the crude product
6.5 g (72%). Recrystallization from aqueous ethanol
gave 5 g (55%) of selenadiazole IIa as light brown
plates with mp 103 105 C; Rf 0.4 (benzene). IR spec-
C6H3C CH]+. Found, %: C 45.03, 44.88; H 3.51,
3.57. C9H8N2OSe. Calculated, %: C 45.0; H 3.33.
2-Methylselenobenzofuran (VIIIa). A suspension
of 0.4 g (1.8 mmol) of selenadiazole IIa, 5 ml of
anhydrous acetone, and 0.3 g (2.2 mmol) of K2CO3
was refluxed for 2 h under vigorous stirring, and
0.43 g (3 mmol) of methyl iodide was added to the
colored mixture. The mixture was refluxed for 1 h
and filtered, and the filtrate was evaporated under
reduced pressure. The residue was subjected to
chromatography on a 3 20-cm column charged with
silica gel L 40/100 m (eluent heptane CCl4, 1:1).
Removal of the solvent from the appropriate fraction
gave 0.29 g (76%) of compound VIIIa as a light
yellow oil, Rf 0.7 (heptane CCl4, 1:1). IR spectrum,
1
trum (5% solution in MeCN), , cm : 3525, 3336,
2995, 2940, 1710, 1590, 1312, 1268, 1245, 1060, 919,
805, 760, 703, 490. 1H NMR spectrum (DMSO-d6), ,
ppm: 6.98 q (5-H), 7.06 d (3-H), 7.27 q (4-H), 8.24 d
2
(6-H), 10.1 s (5-H, selenadiazole, JH, Se = 42 Hz),
10.35 s (OH). 13C NMR spectrum (DMSO-d6),
,
ppm: 116.4 (C3), 118.8 (C1) 119.5 (C5), 129.6 (C6C),
1
130.1 (C4), 142.1 d (C5, selenadiazole, JC, H = 196,
1JC, Se = 133 Hz), 154.7 (C2), 155.2 (C4, selenadi-
azole). Mass spectrum, m/z, (Irel, %): 226 (1.5) M+,
198 (11.4) [M N2]+, 197 (11.3) [M N2 H]+, 118
(100), [2-HOC6H4C CH]+. Found, %: C 42.21,
42.33; H 2.91, 3.03. C8H6N2OSe. Calculated, %:
C 42.69; H 2.69.
1
, cm : 3058, 2910, 2820, 1595, 1430, 1296, 1248,
1
1167, 1035, 1000, 913, 873, 736, 608. H NMR spec-
trum (CDCl3), , ppm: 2.41 s (SeCH3), 6.80 s (3-H),
7.16 t.d (5-H), 7.24 t.d (6-H), 7.48 d (7-H), 7.57 d
(4-H). 13C NMR spectrum (CDCl3), C, ppm: 8.0
4-(2-Hydroxy-4-methylphenyl)-1,2,3-selenadi-
azole (IIb) was synthesized as described above for
compound IIa from 6.7 g (33 mmol) of semicarba-
zone Ib, 15 ml of AcOH, and 3.9 g (35 mmol) of
selenium dioxide. Yield 5.5 g (70%). Light brown
plates, mp 108 109 C (from aqueous ethanol), Rf 0.54
(CH3Se), 110.8 (C3), 111.5 (C7), 120.0 (C4), 122.8
(C5), 123.9 (C6), 128.8 (C9), 145.0 (C2), 157.0 (C8).
Mass spectrum, m/z, (Irel, %): 212 (100) M+, 197
(83.8) [M CH3]+, 169 (33.2) [M CH3 CO]+, 132
(10.2) [M Se]+, 131 (15.3) [M HSe]+, 89 (44.6)
[C7H6]+. Found, %: C 46.89, 47.12; H 3.93, 3.62.
C9H8OSe. Calculated, %: C 47.17; H 3.77.
1
(CHCl3). H NMR spectrum (CDCl3), , ppm: 2.37 s
(CH3), 6.8 d (5-H), 6.95 s (3-H), 7.53 d (6-H), 9.4 s
2
(5-H, selenadiazole, JH, Se = 40 Hz), 10.01 s (OH).
2-Benzylselenobenzofuran (VIIIb). A suspension
of 0.5 g (2.2 mmol) of selenadiazole IIa, 5 ml of
anhydrous acetone, 0.31 g (2.4 mmol) of benzyl
chloride, and 0.6 g (4.3 mmol) of K2CO3 was refluxed
for 5 h with protection from light until initial com-
pound IIa disappeared (TLC). The precipitate was
filtered off, and the light brown solution was
evaporated under reduced pressure. The tarry residue
was subjected to chromatography on a 3 20-cm
column charged with silica gel L 40/100 m, using
benzene as eluent. Removal of the solvent from the
appropriate fraction gave 0.41 g (65%) of compound
VIIIb as a light yellow oil, Rf 0.8 (benzene). IR spec-
13C NMR spectrum (CDCl3), C, ppm: 21.31 (CH3),
113.55 (C1), 118.4 (C3), 121.3 (C5), 127.32 (C6),
1
1
136.7 (C5, selenadiazole, JC, H = 190, JC, Se
=
135 Hz), 141.54 (C4), 155.46 (C2), 162.33 (C4,
selenadiazole). Mass spectrum, m/z (Irel, %): 240 (1.7)
M+, 212 (8.7) [M N2]+, 132 (100) [2-HO-4-CH3-
C6H3C CH]+. Found, %: C 44.75, 44.91; H 3.43,
3.57. C9H8N2OSe. Calculated, %: C 45.0; H 3.33.
4-(2-Hydroxy-5-methylphenyl)-1,2,3-selenadi-
azole (IIc) was synthesized as described above for
compound IIa from 6.7 g (33 mmol) of semicarba-
zone Ic, 15 ml of AcOH, and 3.9 g (35 mmol) of
selenium dioxide. Yield 5.5 g (70%). Light brown
plates, mp 96 98 C (from aqueous ethanol), Rf 0.36
1
trum, , cm : 3060, 3030, 2920, 2850, 1916, 1495,
1440, 1302, 1253, 1160, 1040, 921, 750, 698, 600.
1H NMR spectrum (CCl4), , ppm: 7.61 6.4 m
(Harom), 6.52 s (3-H), 3.96 s (CH2). Mass spectrum,
m/z (Irel, %): 288 (38.7) M+, 197 (19.8) [M CH2Ph]+,
169 (16.8) [M CH2Ph CO]+, 91 (100) [C7H7]+.
Found, %: C 54.12, 53.81; H 3.34, 3.62. C15H12OSe.
Calculated, %: C 53.92; H 3.54.
o-Methoxyphenylethynyl methyl selenide (X).
A suspension of 0.4 g (1.8 mmol) of selenadiazole
IIa, 5 ml of anhydrous acetone, 0.426 g (3 mmol) of
methyl iodide, and 0.3 g (2.2 mmol) of K2CO3 was
1
(benzene). H NMR spectrum (CDCl3), , ppm: 2.34 s
(CH3), 7.03 d (5-H), 7.15 d (4-H), 7.45 s (6-H), 9.52 s
2
(5-H, selenadiazole, JH, Se = 40 Hz), 9.89 s (OH).
13C NMR spectrum (CDCl3), C, ppm: 20.54 (CH3),
115.76 (C1), 117.89 (C3), 127.7 (C5), 129.3 (C6),
1
1
131.77 (C5, selenadiazole, JC, H = 190, JC, Se
=
135 Hz), 137.44 (C4), 153.37 (C2), 162.26 (C4, selena-
diazole). Mass spectrum, m/z, (Irel, %): 240 (8.9)
M+, 212 (54.6) [M N2]+, 132 (100) [2-HO-4-CH3-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

4-(2-HYDROXYARYL)-1,2,3-SELENADIAZOLES AS PRECURSORS OF . . .
1647
refluxed for 5 h with protection from light until initial
compound IIa disappeared. An additional portion of
methyl iodide, 0.21 g (1.5 mmol), was added, and the
mixture was stirred for 15 min. The resulting suspen-
sion was filtered, and the light brown filtrate was
evaporated under reduced pressure. The tarry residue
was subjected to chromatography on a 3 20-cm
column charged with silica gel L 40/100 m, using
benzene as eluent. A fraction containing product X
was evaporated under reduced pressure. Yield 130 mg
(33%), light yellow oily substance; Rf 0.71 (benzene),
364 (19) M+, 231 (36) [M 2-O-C8H5O]+, 197 (10)
[M 2,4-(NO2)2C6H3Se]+, 133 (100) [M 2-NO-4-
NO2C6H3Se]+, 89 (14) [C7H6]+. Found, %: C 46.37,
46.18; H 2.45, 2.62. C14H8N2O5Se. Calculated, %:
C 46.15; H 2.20.
2-(2,4-Dinitrophenylseleno)-6-methylbenzofuran
(XIb) was synthesized as described above for com-
pound XIa from 0.239 g (1 mmol) of selenadiazole
IIb, 0.16 g (1.2 mmol) of K2CO3, and 0.202 g
(1 mmol) of 2,4-dinitrochlorobenzene. By column
chromatography we isolated 0.21 g (56%) of product
XIb as yellow crystals with mp 162 165 C (from
1
0.2 (heptane CCl4, 1:1). IR spectrum, , cm : 3060,
3000, 2926, 2830, 2150, 1589, 1562, 1485, 1440,
2-propanol), Rf 0.7 (CHCl3). 1H NMR spectrum
(CDCl3), , ppm: 2.53 s (CH3) 6.76 s (3-H), 7.18 d
(5-H), 7.33 s (7-H), 7.35 d (4-H), 7.56 d (6-H, C6H3),
8.15 d.d (5-H, C6H3), 9.16 d (3-H, C6H3). 13C NMR
spectrum (CDCl3), C, ppm: 21.8 (CH3), 111.4 (C3),
1
1250, 1180, 1160, 1110, 1043, 1020, 913, 743. H
NMR spectrum (CDCl3), , ppm: 2.38 s (SeCH3),
3.87 s (OCH3), 6.80 d (3-H), 6.88 t.d (5-H), 7.29 t.d
(4-H), 7.40 d (6-H). 13C NMR spectrum (CDCl3),
C, ppm: 9.93 (CH3Se), 55.7 (OCH3), 75.0 (C CSe),
94.3 (C CSe), 110.5 (C6), 120.3 (C3), 123.1 (C4),
129.5 (C5), 133.3 (C2), 157.0 (C1), 110.8 (C3), 111.5
(C7), 120.0 (C4), 122.8 (C5), 123.9 (C6), 128.8 (C9),
145.0 (C2), 157.0 (C8). Mass spectrum, m/z, (Irel, %):
226 (63.6) M+, 211 (6.3) [M CH3]+, 183 (6.3) [M
CH3 CO]+, 168 (14) [M 2CH3 CO]+, 131 (100)
[M CH3Se]+, 91 (24.7) [C7H7]+. Found, %: C 52.89,
53.02; H 4.63, 3.71. C10H10OSe. Calculated, %:
C 53.1; H 4.42.
111.9 (C7), 120.7 (C5, C6H3), 121 (C4), 121.4 (C5),
125.3 (C1, C6H3), 125.4 (C6), 127.3 (C9), 131.8 (C5,
C6H3), 137.2 (C6, C6H3), 140.3 (C2), 143.2 (C4,
C6H3), 147 (C2, C6H3), 158.6 (C8). Mass spectrum,
m/z, (Irel, %): 378 (10) M+, 231 (7) [M 2-O-6-CH3-
C8H4O]+, 211 (2) [M 2,4-(NO2)2C6H3Se]+, 147 (100)
[M 2-NO-4-NO2C6H3Se]+. Found, %: C 47.39,
47.61; H 2.23, 2.45. C15H10N2O5Se. Calculated, %:
C 47.62; H 2.64.
2-(2,4-Dinitrophenylseleno)-5-methylbenzofuran
(XIc) was synthesized as described above for com-
pound XIa from 0.5 g (2.08 mmol) of selenadiazole
IIc, 0.344 g (2.49 mmol) of K2CO3, and 0.42 g
(2.08 mmol) of 2,4-dinitrochlorobenzene. Yield 0.5 g
(63%), yellow crystals, mp 157 159 C (from 2-pro-
2-(2,4-Dinitrophenylseleno)benzofuran (XIa).
A suspension of 0.226 g (1 mmol) of selenadiazole
IIa, 10 ml of anhydrous acetonitrile, and 0.16 g
(1.2 mmol) of K2CO3 was refluxed for 10 30 min
under vigorous stirring, and 0.202 g (1 mmol) of
2,4-dinitrochlorobenzene in 5 ml of acetonitrile was
added to the dark cherry reaction mixture. The mixture
turned yellow green. It was refluxed for 5 h, cooled
to 20 C, poured into 25 ml of water, neutralized with
6% hydrochloric acid, and extracted with chloroform
(2 10 ml). The extract was dried over calcined
calcium chloride and evaporated under reduced pres-
sure. The residue was subjected to chromatography
on a 3 20-cm column charged with silica gel L
40/100 m (eluent heptane CHCl3, 1:1). Yield 0.15 g
(41%), yellow crystals with mp 166 167 C (from
1
panol), Rf 0.57 (CHCl3). H NMR spectrum (CDCl3),
, ppm: 2.49 s (CH3), 6.72 s (3-H), 7.35 d (6-H), 7.3 s
(4-H), 7.45 d (7-H), 7.62 d (6-H, C6H3), 8.15 d.d
(5-H, C6H3), 9.16 d (3-H, C6H3). 13C NMR spectrum
(CDCl3), C, ppm: 21.7 (CH3), 111.7 (C3), 120.9 (C7),
121.6 (C3, C6H3), 121.7 (C4), 127.7 (C5), 128.3 (C1,
C6H3), 128.4 (C6), 132.2 (C9), 133.82 (C5, C6H3),
141.5 (C6, C6H3), 143.5 (C2), 145.4 (C4, C6H3), 146.5
(C2, C6H3), 158.6 (C8). Mass spectrum, m/z, (Irel, %):
378 (15) M+, 231 (15) [M 2-O-5-CH3C8H4O]+, 211
(4) [M 2,4-(NO2)2C6H3Se]+, 147 (100) [M 2-NO-4-
NO2C6H3Se]+, 91 (10) [C7H7]+. Found, %: C 47.34,
47.53; H 2.47, 2.61. C15H10N2O5Se. Calculated, %:
C 47.62; H 2.64.
1
2-propanol), Rf 0.55 (heptane CHCl3, 1:1). H NMR
spectrum (CDCl3), , ppm: 6.87 s (3-H), 7.15 t.d
(5-H), 7.32 t.d (6-H), 7.43 d (7-H), 7.52 d (4-H),
7.72 d (6-H, dinitrophenyl), 8.17 d.d (5-H, dinitro-
phenyl), 9.17 d (3-H, dinitrophenyl). 13C NMR
1H NMR study of the decomposition of 4-(2-hy-
droxyphenyl)-1,2,3-selenadiazole (IIa). A solution
of compound IIa in DMSO-d6 was placed in an NMR
ampule, an equimolar amount of tetrabutylammonium
spectrum (CDCl3), C, ppm: 111.3 (C3), 112.2 (C7),
116.3 (C3, C6H3), 120.9 (C4), 122.3 (C5), 124.2 (C1,
C6H3), 124.7 (C6), 128.3 (C9), 132.2 (C5, C6H3),
1
141.6 (C6, C6H3), 145.2 (C2), 147.5 (C4, C6H3), 157.1
hydroxide was added, and H NMR spectra were re-
(C2, C6H3), 158.0 (C8). Mass spectrum, m/z (Irel, %):
corded on a Bruker AMX-400 instrument (400 MHz).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

1648
PETROV et al.
After 5 min, signal from the hydroxy proton of the
initial compound disappeared, and those correspond-
ing to benzofuran-2-selenolate (VIIa) appeared. H
8. Petrov, M.L., Abramov, M.A., Dehaen, W., and
Toppet, S., Tetrahedron Lett., 1999, vol. 40, no. 20,
pp. 3903 3904.
1
NMR spectrum (DMSO-d6), , ppm: 6.02 s (3-H),
7.07 d (4-H and 7-H), 6.77 t and 6.87 t (5-H and 6-H).
13C NMR spectrum (DMSO-d6), C, ppm: 105.7 (C3),
107.9 (C7), 115.2 (C5), 118.4 (C4), 121 (C6), 132.8
(C9), 155.9 (C8), 164.4 (C2).
9. Petrov, M.L., Abramov, M.A., and Dehaen, W.,
Russ. J. Org. Chem., 2000, vol. 36, no. 4, pp. 605
606.
10. Lalezari, I., Shaffice, A., and Yalpani, M., Tetra-
hedron Lett., 1969, vol. 58, pp. 5105 5106.
11. Silverstein, R.M., Bassler, G.C., and Morrill, T.C.,
Spectrometric Identification of Organic Compounds,
New York: Wiley, 1974, 3rd ed. Translated under
the title Spektrometricheskaya identifikatsiya organi-
cheskikh soedinenii, Moscow: Mir, 1977, p. 166.
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