New synthesis of 2-aminobenzo[b]selenophenes from 4-(2-chloroaryl)-1,2,3- selenadiazoles

Full text of DOI:10.1134/S1070428012010265

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 1, pp. 147–149. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © M.L. Petrov, A.G. Lyapunova, D.A. Androsov, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 1,
pp. 151–153.
SHORT
COMMUNICATIONS
New Synthesis of 2-Aminobenzo[b]selenophenes
from 4-(2-Chloroaryl)-1,2,3-selenadiazoles
M. L. Petrov, A. G. Lyapunova, and D. A. Androsov
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 190013 Russia
e-mail: mlpetrov@lti-gti.ru
Received May 27, 2011
DOI: 10.1134/S1070428012010265
Up to now, the only reported method for the syn-
thesis of 2-aminobenzo[b]selenophene is based on
reduction of 2-nitrobenzo[b]selenophene. 2-Amino-
benzo[b]selenophene is used for the preparation of
selenium-containing polymethine dyes [1]. Beckmann
rearrangement of 2-acetyl-3-phenylbenzo[b]seleno-
phene oxime by the action of polyphosphoric acid gave
2-acetylamino-3-phenylbenzo[b]selenophene which
can be used in organic synthesis [2]. One more known
2-aminobenzo[b]selenophene derivative, 2-benzoyl-
amino-3-phenylbenzo[b]selenophene was synthesized
by reaction of diphenyldiazomethane with benzoyl iso-
selenocyanate [3].
selenolate (IVa) which reacted with diethylamine to
produce potassium 2-(2-chlorophenyl)-1-diethylamino-
etheneselenolate (Va). However, compound Va did not
undergo cyclization via intramolecular nucleophilic
replacement of the chlorine atom, and acidification of
the reaction mixture afforded 2-(2-chlorophenyl)-N,N-
diethylselenoacetamide (VI) (Scheme 2).
Likewise, 4-(2-chloro-5-nitrophenyl)-1,2,3-selena-
diazole (IIIb) reacted with KOH in excess secondary
amine (morpholine or piperidine) to generate potas-
sium 2-(2-chloro-5-nitrophenyl)ethyneselenolate (IVb)
which took up secondary amine molecule with forma-
tion of potassium 2-(2-chloro-5-nitrophenyl)-1-dialkyl-
aminoetheneselenolate Vb or Vc. Intramolecular
cyclization of the latter produced 2-aminobenzo[b]-
selenophenes VIIb and VIIc (Scheme 3).
We propose a new procedure for the synthesis of
2-aminobenzo[b]selenophenes from readily accessible
4-(2-chloroaryl)-1,2,3-selenadiazoles. The reaction of
2-chloroacetophenones Ia and Ib with semicarbazide
hydrochloride gave the corresponding semicarbazones
IIa and IIb which were converted into 4-(2-chloro-
aryl)-1,2,3-selenadiazoles IIIa and IIIb by the action
of selenium dioxide (Scheme 1).
The structure of compounds VI, VIIb, and VIIc
1
was confirmed by their H and 13C NMR and mass
spectra, as well as by comparing their spectral param-
eters with those of sulfur-containing analogs [4].
2-Chloro-5-nitroacetophenone semicarbazone
(IIb). A mixture of 4.40 g (2.2 mmol) of 2-chloro-5-
nitroacetophenone (Ib) [5] and 2.95 g (26 mmol) of
semicarbazide hydrochloride was dissolved in 70 ml of
propan-2-ol under stirring and heating, and a hot solu-
tion of 4.34 g (53 mmol) of sodium acetate in 5 ml of
Treatment of 4-(2-chlorophenyl)-1,2,3-selenadi-
azole (IIIa) with potassium hydroxide in excess
diethylamine resulted in decomposition of the five-
membered ring with elimination of nitrogen molecule
and formation of potassium 2-(2-chlorophenyl)ethyne-
Scheme 1.
N
O
Me
N
H
6
Se
4'
R
R
N
NH2
R
5
H2NNHC(O)NH2 ·HCl
SeO2
Me
N
5'
1
O
4
2
Cl
Cl
Cl
3
Ia, Ib
IIa, IIb
IIIa, IIIb
R = H (a), O2N (b).
147

PETROV et al.
148
Scheme 2.
Se– K+
N
N
Se
KOH, HNEt2, Δ
NEt2
Se– K+
NEt2
–N2
Se
Cl
Cl
Cl
Cl
IIIa
IVa
Va
VI
Scheme 3.
NO2
NO2
O2N
NR2
O2N
KOH, HNR2, Δ
–N2
NR2
N
Se– K+
–Cl–
Se
N
Cl
Vb, Vc
Cl
Cl
Se– K+
Se
IIIb
IVb
VIIb, VIIc
R2N = morpholino (b), piperidino (c).
1
hexane, 1:4). H NMR spectrum (CDCl3), δ, ppm:
7.24–7.33 m (5-H, 5-H), 7.43 d.d (6-H, J = 7.5,
1.1 Hz), 7.94 d.d (3-H, J = 7.4, 2.0 Hz), 9.62 s (5′-H,
water was added. The precipitate was filtered off and
dissolved in a minimal amount of hot water, the solu-
tion was heated for 2 h under reflux, cooled, and left
overnight, and the precipitate was filtered off, washed
with water and propan-2-ol, and dried. Yield 4.95 g
(88%). White crystals, mp 214–217°C, Rf 0.1 (CHCl3–
Se–H satellites, J = 40 Hz). 13C NMR spectrum
2
(CDCl3), δC, ppm: 126.9 (C6), 129.6 (C5), 130.2 (C4),
130.4 (C1), 132.0 (C3), 141.89 (C2), 142.1 (C5′), 158.6
(C4′). Mass spectrum, m/z (Irel, %): 216 (64.2) [M – N2]+,
136 (100) [M – N2 – Se]+, 101 (30), 75 (52.5), 50 (35.0).
Found, %: C 39.33, 39.71; H 2.32, 2.41. C8H5ClN2Se.
Calculated, %: C 39.45; H 2.07. M 243.55.
1
MeOH, 9:1). H NMR spectrum (DMSO-d6), δ, ppm:
2.23 s (3H, CH3), 6.33 br.s (2H, NH2), 7.71 d (3-H, J =
8.6 Hz), 8.17 d.d (4-H, J = 8.6, 2.4 Hz), 8.22 d (6-H,
J = 8.6 Hz), 9.70 s (1H, NH). 13C NMR spectrum
(CDCl3), δC, ppm: 16.88 (CH3), 123.53 (C6), 124.75
(C4), 130.74 (C3), 137.97 (C2), 140.0 (C1), 142.08 (C5),
145.96 (C=N), 156.35 (C=O). Mass spectrum, m/z
(Irel, %): 256 (12.5) [M]+, 212 (15.0) [M – CONH2]+,
195 (26.7), 178 (35.8) [M – CONH2 – NO2]+, 132
(40.0), 102 (32.5), 75 (37.5), 44 (100). Found, %:
C 42.27, 42.34; H 3.48, 3.75. C9H9ClN4O3. Calculated,
%: C 42.12; H 3.53. M 256.65.
4-(2-Chloro-5-nitrophenyl)-1,2,3-selenadiazole
(IIIb). Selenium dioxide, 0.71 g (6.4 mmol), was
added under stirring to a suspension of 1.5 g
(5.8 mmol) of 2-chloro-5-nitroacetophenone semicar-
bazone (IIb) in 25 ml of glacial acetic acid. The mix-
ture was protected from light, stirred for 2 h at room
temperature, for 1 h at 50°C (water bath), and for 4 h
at 66°C, cooled to room temperature, and poured into
100 ml of water. The precipitate was filtered off,
washed with water, dried in air with protection from
light, and recrystallized from chloroform–methanol.
Yield 1.06 g (63%), light orange crystals, mp 136–
140°C (decomp.), Rf 0.46 (EtOAc–hexane, 1:4).
1H NMR spectrum (CDCl3), δ, ppm: 7.73 d (3-H, J =
8.8 Hz), 8.22 d.d (4-H, J = 8.8, 2.3 Hz), 8.96 d (6-H,
J = 2.0 Hz), 9.87 s (5′-H, Se–H satellites, 2J = 40 Hz).
13C NMR spectrum (CDCl3), δC, ppm: 124.19 (C4),
127.29 (C6), 131.66 (C3), 132.17 (C1), 138.96 (C2),
143.57 (C5′), 146.88 (C5), 156.92 (C4′). Mass spectrum,
m/z (Irel, %): 261 (88.5) [M – N2]+, 215 (60.7) [M –
N2 – NO2]+, 180 (65.6), 123 (55.7), 99 (86.9), 74
(100), 50 (47.5). Found, %: C 33.52, 33.69; H 1.56,
1.75. C8H4ClN3O2Se. Calculated, %: C 33.30; H 1.40.
M 288.55.
4-(2-Chlorophenyl)-1,2,3-selenadiazole (IIIa).
Selenium dioxide, 0.87 g (7.8 mmol), was added under
stirring to a suspension of 1.5 g (7.1 mmol) of
2-chloroacetophenone semicarbazone (IIa) [6] in 15 ml
of glacial acetic acid. The mixture was protected from
light, stirred for 1.5 h at room temperature, for 1 h at
50°C (water bath), and for 3 h at 66–68°C, cooled to
room temperature, poured into 75 ml of water, and
extracted with chloroform (3×15 ml). The extract was
washed with an aqueous solution of sodium carbonate
(3×10 ml) and dried over Na2SO4, the solvent was dis-
tilled off under reduced pressure, and the residue was
purified by column chromatography on silica gel using
hexane–ethyl acetate (8 :1) as eluent. Yield 1.11 g
(65%), dark orange oily liquid, Rf 0.66 (EtOAc–
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 1 2012

NEW SYNTHESIS OF 2-AMINOBENZO[b]SELENOPHENES
149
5-Nitro-2-piperidinobenzo[b]selenophene (VIIc)
was synthesized in a similar way from 0.5 g (1.7 mmol)
of 1,2,3-selenadiazole (IIIb) using 0.23 g (4.0 mmol)
of potassium hydroxide and 5 ml (50.5 mmol) of piper-
idine. After neutralization, the mixture was extracted
with ethyl acetate (3×10 ml), the extract was dried
over Na2SO4, the solvent was distilled off under
reduced pressure, and the residue was subjected to
column chromatography on silica gel using hexane–
ethyl acetate (5:1) as eluent. Yield 0.25 g (47%), dark
red crystals, mp 144–148°C, Rf 0.62 (EtOAc–hexane,
2-(2-Chlorophenyl)-N,N-diethylethaneseleno-
amide (VI). A mixture of 1 g (4.1 mmol) of
4-(2-chlorophenyl)-1,2,3-selenadiazole (IIIa), 5 ml
(48 mmol) of diethylamine, and 0.55 g (9.8 mmol) of
KOH was heated at 56–58°C on a water bath under
stirring until nitrogen no longer evolved. The mixture
was then cooled to room temperature, poured into
50 ml of water, neutralized with dilute hydrochloric
acid, and extracted with chloroform (3×10 ml). The
extract was dried over Na2SO4, the solvent was
distilled off under reduced pressure, and the residue
was crystallized from hexane–methanol. Yield 0.84 g
(71%), yellow crystals, mp 39–41°C, Rf = 0.40
1
1:4). H NMR spectrum (CDCl3), δ, ppm: 1.64 q (2H,
NCH2CH2CH2, J = 4.8 Hz), 1.73 t (4H, NCH2CH2, J =
5.0 Hz), 3.26 t (4H, NCH2, J = 5.2 Hz), 6.22 s (3-H),
7.68 d (7-H, J = 8.5 Hz), 7.78 d.d (6-H, J = 8.6,
1.9 Hz), 8.19 d (4-H, J = 1.8 Hz). 13C NMR spectrum
(CDCl3), δC, ppm: 23.59 (NCH2CH2CH2), 25.03
(NCH2CH2), 52.6 (NCH2), 99.21 (C7), 114.73 (C4),
116.12 (C6), 124.56 (C7), 140.7 (C3a), 144.15 (C7a),
146.2 (C2), 162.86 (C5). Mass spectrum, m/z (Irel, %):
310 (37.2) [M]+, 264 (13.6) [M – NO2]+, 89 (31.8), 55
(34), 41 (100). Found, %: C 50.34, 50.57; H 4.53,
4.82. C13H14N2O2Se. Calculated, %: C 50.49; H 4.56.
M 309.22.
1
(EtOAc –hexane, 1:8). H NMR spectrum (CDCl3), δ,
ppm: 1.06 t (3H, CH3, J = 7.1 Hz), 1.25 t (3H, CH3,
J = 7.1 Hz), 3.31 q (2H, CH2, J = 7.1 Hz), 4.02 q (2H,
CH2, J = 7.0 Hz), 4.29 s (2H, CH2), 7.07–7.16 m (4-H,
5-H), 7.22–7.30 m (6-H, J = 7.1 Hz), 7.36 d (3-H, J =
7.1 Hz). 13C NMR spectrum (CDCl3), δC, ppm: 47.29
(CH3), 50.6 (CH2CH3), 51.53 (CH2C=Se), 127.03 (C5),
128.14 (C4), 128.93 (C3), 129.18 (C6), 133.61 (C1),
201.56 (C=Se). Mass spectrum, m/z (Irel, %): 289
(10.0) [M]+, 254 (100) [M – Cl]+, 180 (18.3), 136
(29.2), 125 (87.5), 89 (58.3), 72 (57.5). Found, %:
C 50.23, 50.31; H 5.23, 5.47. C12H16ClNSe. Calculat-
ed, %: C 49.93; H 5.59. M 288.67.
The melting points were determined on a Boetius
1
melting point apparatus. The H and 13C NMR spectra
were recorded on a Bruker AMX-400 spectrometer at
400 and 100 MHz, respectively; the chemical shifts
were measured relative to the residual proton and
carbon signals of deuterated solvents. The mass spectra
(electron impact, 70 eV) were obtained on a Finnigan
INCOS MAT 95 instrument with direct sample admis-
sion into the ion source (ion source temperature
200°C); the m/z values are given for 80Se isotope. The
progress of reactions was monitored by TLC on
Silicagel 60 F254 plates; spots were detected by UV
irradiation or treatment with iodine vapor.
2-Morpholino-5-nitrobenzo[b]selenophene
(VIIb). A suspension of 0.23 g (4.0 mmol) of KOH,
5 ml (57.5 mmol) of morpholine, and 0.5 g (1.7 mmol)
of 1,2,3-selenadiazole IIIb was stirred for 24 h at room
temperature in a stream of argon. The mixture was
poured into 75 ml of water, neutralized with dilute
hydrochloric acid, and extracted with CHCl3 (3×10 ml).
The extract was dried over Na2SO4, the solvent was
distilled off under reduced pressure, and the residue
was subjected to column chromatography on silica gel
using hexane–ethyl acetate (5:1) as eluent. Yield 0.37 g
(71%), bright orange crystals, mp 173–176°C, Rf 0.31
REFERENCES
1
(EtOAc–hexane, 1:4). H NMR spectrum (CDCl3), δ,
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ppm: 3.26 t (4H, NCH2, J = 4.9 Hz), 3.86 t (4H, CH2,
J = 4.9 Hz), 6.33 s (3-H), 7.72 d (7-H, J = 8.5 Hz),
7.84 d.d (6-H, J = 8.8, 2.0 Hz,), 8.24 d (4-H, J =
2.0 Hz). 13C NMR spectrum (CDCl3), δC, ppm: 51.36
(NCH2), 65.96 (OCH2), 100.58 (C3), 115.44 (C6),
116.75 (C4), 124.77 (C7), 140.81 (C3a), 143.42 (C7a),
146.24 (C2), 162.51 (C5). Mass spectrum, m/z (Irel, %):
312 (93) [M]+, 266 (25) [M – NO2]+, 254 (63), 208
(40), 181 (51), 127 (38), 116 (37), 102 (27), 89 (100),
75 (25). Found, %: C 46.27, 46.52; H 4.01, 4.17.
C12H12N2O3Se. Calculated, %: C 46.31; H 3.89.
M 311.20.
5. Thorp, L. and Brunskill, E.R., J. Am. Chem. Soc., 1915,
vol. 37, p. 1258.
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