Unsymmetrical benzotristhiazole: A new electron-withdrawing core for octupolar chromophores

Article abstract of DOI:10.1002/jhet.1530

A six-step synthesis of the unsymmetrical trimethylbenzotristhiazole has been developed. Starting from 2-methylbenzothiazole following nitration, reduction, acetylation, thionation, and twofold cyclization, the desired trimethylbenzotristhiazole was obtained in good yield. Its condensation with donor-substituted benzaldehydes presents the way to new octupolar chromophores. The attempt to synthesize such benzotristhiazole from dinitroaniline failed; this procedure afforded a new benzimidazole derivative.

Full text of DOI:10.1002/jhet.1530

May 2013
Unsymmetrical Benzotristhiazole: A New Electron-Withdrawing Core for
Octupolar Chromophores
563
Andrea Fülöpová, Peter Magdolen,* Miroslava Károlyiová, Ivica Sigmundová, and Pavol Zahradník
Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava, Slovakia
*
E-mail: magdolen@fns.uniba.sk
Received June 22, 2011
DOI 10.1002/jhet.1530
Published online in Wiley Online Library (wileyonlinelibrary.com).
H C
S
S
CH3
3
O N
N
N
2
S
N
CH3
S
N
NO2
CH3
A six-step synthesis of the unsymmetrical trimethylbenzotristhiazole has been developed. Starting from
-methylbenzothiazole following nitration, reduction, acetylation, thionation, and twofold cyclization, the
2
desired trimethylbenzotristhiazole was obtained in good yield. Its condensation with donor-substituted benzal-
dehydes presents the way to new octupolar chromophores. The attempt to synthesize such benzotristhiazole
from dinitroaniline failed; this procedure afforded a new benzimidazole derivative.
J. Heterocyclic Chem., 50, 563 (2013).
INTRODUCTION
hyperpolarizability [16,17]. Mainly, the thiazole derivatives
have a great potential to be used as NLO chromophores [18].
In our effort to prepare a new thiazole-based chromophore
with enhanced nonlinear optical response for potential
optoelectronic applications [19–24], we focused our
attention on the unsymmetrical isomer of benzotristhiazole
as an appropriate candidate for a new type of octupolar
chromophore with electron-withdrawing core. The lack of
symmetry in the benzotristhiazole moiety could bring
additional advantage in NLO properties.
The field of nonlinear optics (NLO) has been being
developed for the past few decades as a promising area with
important applications in the domain of optoelectronics and
photonics. Within this framework, organic chromophores
have received major attention because of their chemical
flexibility and molecular electronic response that allows the
molecular engineering of optical nonlinearities [1–3]. Most
organic compounds with NLO response are characterized by
the simple dipolar structure: strong electron-withdrawing
and electron-releasing groups are connected through an
efficient p-electron conjugated bridge to yield a highly
electronically asymmetric and hyperpolarizable NLO
chromophore [4,5]. More recently, the attention in this field
has turned toward quadrupolar, octupolar, or multibranched
molecules because of their potential high nonlinear
response [6–10].
Unlike the symmetrical benzotristhiazole skeleton which
synthesis was published via several independent routes
[25,26], an unsymmetrical isomer has not been prepared and
described yet. Our aim was to synthesize this unsymmetrical
benzotristhiazole substituted with groups that could be further
derivatized to produce conjugate push–pull branches.
These demands are fulfilled by a methyl group bonded to a
heterocyclic carbon because its hydrogens are acidic
enough to undergo a Knoevenagel type reaction with
aromatic aldehydes.
Among the NLO-active organic molecules, the
compounds containing a heterocyclic fragment are charac-
terized by a high photochemical and thermal stability, good
optical properties, high laser damage threshold, and low cost
that are the criteria necessary for the practical application in
optoelectronic devices.
RESULTS AND DISCUSSION
Enhanced nonlinearities are achieved by replacing a
benzene ring with a heterocycle (e.g., thiophene, thiazole,
benzothiazole) as a conjugative unit [11–14] because they
have lower resonance stabilization energy upon charge
delocalization than benzene ring does [15]. The incorpo-
ration of a five-membered aromatic with two heteroatoms
into the p-electron bridge can significantly enhance the
The synthesis of symmetrical benzotristhiazole was
0
0
achieved by Jacobson cyclization of N,N′,N -(benzene-1,3,5-
triyl)triethanethioamide. First, we tried to apply this methodol-
ogy for the preparation of the isomeric heterocycle
(Scheme 1).
The commercially available 2,4-dinitroaniline was
chosen as the starting material. Reduction with hydrogen
©
2013 HeteroCorporation

5
64
A. Fülöpová, P. Magdolen, M. Károlyiová, I. Sigmundová, and P. Zahradník
Vol 50
Scheme 1
NH2
NH2
NH2
NHCOCH3
NHCOCH3
NHCSCH
NHCSCH
3
3
NO2
NH2
1
0 % Pd/C, H2
Ac O, DMAP
Lawesson reagent
THF, 2×15 min,
2
THF, r.t., 20 h
THF, 3 bar
1
00 °C, 2 bar
79 %
MWI
NHCSCH3
NO2
1
NHCOCH3
2
67 %
3
Lawesson reagent
THF, 5 min,
K [Fe(CN) ], NaOH
3
6
80-90 °C
1
20°C, 4 bar
MWI
2
7 %
29 %
H
N
H
H
N
S
N
CH3
CH3
N
CH3
N
H C
N
5
S
4
3
on palladium led to 1,2,4-benzenetriamine that was not
isolated but directly acetylated to the respective triple
acetamide. Acetamide 2 was converted to thioamide 3 by
efficient thionation using Lawesson reagent at optimized
temperature under microwave conditions. Triple cyclization
of 3 to the desired benzotristhiazole 10 by Jacobson
procedure failed; the only product that can be reasonably
isolated was imidazolobenzothiazole 4. We assume that
the nucleophilic condensation of ortho-bisthioamide to benz-
imidazole is preferable to the radical cyclization resulting in
formation of two thiazole rings. This is also proved by the
formation of a substituted benzimidazole 5 directly from 2
when higher temperature was applied. After a condensation
reaction with donor-substituted benzaldehydes, the deriva-
tives of compound 4 can be used as new quadrupolar
chromophores of D-p-A-p-D type.
with a substituted benzaldehyde that produced the conju-
gated compound 11 with octupolar symmetry.
The compound 11 represents a three-branched chromo-
phore that enables the charge-transfer from the electron-
releasing diphenylamino substituents to the central
electron-withdrawing benzotristhiazole core.
Although basic compound 10 absorbs light in the UV
spectral region (lmax = 274nm in CHCl ), the three push–
3
pull units in its condensed product 11 give rise to an intensive
charge-transfer band in violet spectral region (l = 445 nm,
max
3
ꢀ1
ꢀ1
e = 106427dm mol cm
in CHCl ). The octupolar
3
structure results also in the changes of emission properties;
the solution of 11 in CHCl exhibited intense long-wave
3
fluorescence band with l = 538 nm. The quantum yield of
F
fluorescence is 0.36 in CHCl compared with perylene.
3
To investigate the possible nonlinear application of the
octupolar structure 11, the quantum chemical calculations
(semiempirical method PM3 [27]) of nonlinear descriptors
have been performed [28]. The calculated value of hyperpo-
To avoid the formation of an imidazole ring, we
proposed an alternative route starting from 2-methyl-4,6-
dinitrobenzotiazole 6 that was prepared via sequentional
two-step nitration from 2-methylbenzotiazole. The following
reduction with metallic iron using ultrasound sonication led
to the benzothiazole diamine 7 (Scheme 2). Acylation with
acetanhydride and subsequent thionation using Lawesson’s
reagent provided the bisthioamide 9. In the key step, the
Jacobson cyclization proceeded in the desired way, and
two thiazole rings were formed in a good yield. The structure
of the target compound was confirmed by spectral methods:
ꢀ
30
larizability b is 54.63 ꢁ 10 esu (standard DANS (4-
dimethylamino-4′-nitrostilbene) = 37.35); the value for
ꢀ
36
second hyperpolarizability g = 602286 ꢁ 10 esu is very
encouraging (DANS = 179,16).
EXPERIMENTAL
Solvents were purified and dried using common methods (THF –
reflux on Na with benzophenone). The reactions where the substrate
was treated under ultrasound conditions were performed using
an ultrasonic submersible generator – UUA Ultragen (20kHz,
1
in H NMR spectra, only three slightly different methyl
1
3
protons were observed, and in C NMR, sets of three closed
signals for methyl carbons as well as for skeletal thiazole
carbons were registered. The reaction ability of the methyl
groups in 10 was proved by a Knoevenagel type reaction
3
00 W) GENTECH. For reactions performed under microwave
irradiation, the reactor Initiator BIOTAGE (max. power 300 W)
(Biotage AB, Uppsala, Sweden) was used. Melting points were
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

May 2013
Unsymmetrical Benzotristhiazole
565
Scheme 2
H N
O N
2
S
H C-CO-HN
3
2
S
N
S
N
Fe / HCl
Ac O, DMAP
2
CH3
CH3
CH3
C H OH, 28 min,
THF, 20 h
2
5
N
ultrasound
9
0%
NO2
6
NH2
NH-CO-CH
3
89 %
8
7
H C
3
S
H C-CS-HN
N
S
3
S
N
S
N
K [Fe(CN) ]
Lawesson reagent
THF,110 °C, 8 min, 4 bar, MWI
7 %
3
6
CH3
CH3
NaOH, r.t.
4 %
7
4
NH-CS-CH3
N
H C
3
9
10
Ph
Ph
N
Ph
Ph
S
N
Ph
OHC
N
N
S
S
N
N
Ph
5
0 % NaOH / DMSO
10 %
Ph
N
11
Ph
measured on a Kofler apparatus Electrothermal IA-9200 (Dresden,
by room temperature for 20 h, and the precipitate was filtered
1
13
ꢂ
Germany) and were not corrected. H NMR and C NMR spectra
were recorded on Varian Gemini 2000 spectrometer (Palo Alto,,
CA). IR spectra were recorded on Thermo Scientific Nicolet iS10
spectrometer (Smart iTR diamond ATR). HRMS were recorded
on a Shimadzu LC-IT-TOF MS instrument (Kyoto, Japan) using
both ESI positive and ESI negative mode. Electronic absorption
spectra were obtained on a Jenway 6705 UV–vis spectrophotometer
off to obtain 1.96 g (79%) of yellowish solid, mp 238–239 C
ꢂ
1
(lit.[29] 239 C); H NMR (methanol, 300 MHz), d = 7.80 (s,
1H, H-3), 7.39 (d, J = 1.3, 2H, H-5 a H-6), 2.15 (s, 3H,
COCH ), 2.14 (s, 3H, COCH ), 2.10 (s, 3H, COCH ).
3
3
3
00
N,N′,N -(benzene-1,2,4-triyl)triethanethioamide (3). In a glass
00
vessel for microwave reactor, the N,N′,N -(benzene-1,2,4-triyl)
triacetamide (2) (1.0 g, 4.0 mmol) was dissolved in dried THF
(10 mL). Lawesson reagent (2.67 g, 6.6 mmol, 1.65 eq) was added,
and the reaction mixture was exposed to microwave irradiation two
(
Bibby Scientific Ltd., Staffordshire, U.K), and fluorescence
measurements were performed on a Hitachi F-2000 fluorescence
spectrophotometer (Hitachi Ltd, Tokyo, Japan). Chromatography
was performed using Swambe Chemicals silica gel 60 A flash
ꢂ
times for 15 min at 100 C. THF was evaporated and the crude
product was purified by column chromatography (silica gel, hexane:
ethyl acetate = 1:1) to obtain 0.8 g (67%) of yellow solid, mp 84–
(
230–400 mesh) or neutral aluminium oxide. 2-Methyl-4,6-dinitro-
ꢂ
benzothiazole (6) was synthesized according to literature.[19]
86 C; IR (powder film): 3194 and 3144 (NH), 3026 (C -H), 2985
Ar
00
N,N′,N -(Benzene-1,2,4-triyl)triacetamide
Dinitroaniline (1) (1.83 g, 10 mmol) was dissolved in dried THF
80 mL) and as catalysator 10 wt.% Pd on carbon (0.1 g,
.9 mmol, 0.09 eq) was added. The solution was hydrogenated
(2).
2,4-
(Csp3-H), 1669 and 1598 (C ═C ), 1531 (NH), 1346 (C═S),
Ar
Ar
ꢀ
1
1
1148 cm
;
H NMR (CDCl , 300 MHz), d =9.51 (bs, 2H,
3
(
0
2ꢁ NH), 9.12 (bs, 1H, NH), 8.46 (d, J=2.0, 1H, H-3), 7.55 (dd,
J=2.2, J= 8.8, 1H, H-5), 7.51 (d, J= 8.6, 1H, H-6), 2.73 (s, 3H,
13
in an autoclave by room temperature and pressure 3 bar. After
the reaction, the catalysator was quickly filtered off to avoid the
auto-oxidation of 1,2,4-triaminobenzene. To the filtrate acetic
anhydride (3.31 mL, 35 mmol, 3.5 eq) and DMAP (0.13 g,
3 3 3
CSCH ), 2.721 (s, 3H, CSCH ), 2.716 (s, 3H, CSCH ); C NMR
(DMSO, 75 MHz), d = 201.1, 201.0, 199.3, 137.9, 134.0, 131.5,
ꢀ
127.2, 121.1, 35.5, 34.0, 33.9; HRMS (EI) m/z [M ꢀ H] Calcd for
C
C
12
H
H
15
3 3
N S : 296.0355; found: 296.0354. Anal. Calcd for
1
mmol, 10 mol%) were added. The reaction mixture was stirred
12
15 3 3
N S : C, 48.45; H, 5.08. Found: C, 48,44; H, 5,08.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

5
66
A. Fülöpová, P. Magdolen, M. Károlyiová, I. Sigmundová, and P. Zahradník
Vol 50
2
,7-Dimethyl-6H-imidazolo[5,4-g]benzothiazole (4).
In a
dissolved in chloroform (50 mL). Organic layer was extracted with
three-necked flask (with reflux condenser, thermometer, and a
saturated solution of Na CO3 (3 ꢁ 25 mL) and with brine
2
funnel) to a 20% aqueous solution of K
3
[Fe(CN)
6
] (10.5mL,
(2 ꢁ 20 mL). After that, it was dried over Na
2 4
SO and concentrated
ꢂ
2
.5 g, 7.6mmol, 10.5 eq) heated at 80–90 C, the solution of N,N′,
under vacuum to obtain 3.21 g (90%) of red-brown solid, mp
00
ꢂ
N -(benzene-1,2,4-triyl)triethanethioamide (3) (0.22 g, 0.72mmol)
in 10% NaOH (7.0 mL, 0.78g, 19.6 mmol, 27 eq.) was added
dropwise (1drop/20 s). The reaction mixture was stirred for
220–222 C; IR (powder film): 3634 and 3388 and 3293 and
3103 (NH), 3033 (C -H), 2981 and 2929 (Csp3-H), 1690 and
Ar
1665 (C═O), 1618 and 1582 and 1559 (C ═C ), 1509 (NH),
Ar
1
Ar
ꢂ
ꢀ1
another 20 min at 80–90 C and then cooled down to room
1434, 1409, 1367, 1258, 1170 cm
;
3
H NMR (CDCl ,
temperature. The aqueous solution was extracted with chloroform
300 MHz), d = 8.62 (bs, 1H, NH), 8.41 (d, J = 1.8, 1H, H-7),
8.11 (d, J = 1.7, 1H, H-5), 7.68 (bs, 1H, NH), 2.78 (s, 3H,
(
2ꢁ 5 mL), dried over Na SO , and concentrated under vacuum
2
4
ꢂ
13
to obtain 0.4 g (27 %) of brown solid, mp (lit. [30]) 204 C;
CH ), 2.30 (s, 3H, COCH ), 2.19 (s, 3H, COCH ); C NMR
3
3
3
1
H NMR (CDCl
3
, 300MHz), d = 7.80 (d, J = 8.6, 1H, H-4), 7.49
), 2.69
, 75 MHz), d = 164.2, 151.3,
50.3, 132.2, 132.0, 128.9, 128.8, 116.9, 20.0, 15.2.
N-(2-Methyl-1H-benzo[d]imidazol-6-yl)ethanethioamide
3
(CDCl , 75 MHz), d = 169.0, 168.9, 165.2, 139.4, 136.0, 135.9,
+
(
(
d, J = 8.4, 1H, H-5), 3.84 (bs, 1H, NH), 2.86 (s, 3H, CH
s, 3H, CH
3
131.0, 107.5, 107.1, 24.8, 24.5, 19.8; HRMS (EI) m/z [M + H]
Calcd for C12 S: 264.0801; found: 264.0799. Anal.
Calcd for C H N O S: C, 54.74; H, 4.98; N, 15.96; S, 12.18.
13
3
); C NMR (CDCl
3
H
13
N
3
O
2
1
1
2
13
3 2
Found: C, 54,34; H, 5,13; N, 15,55; S, 11,66.
00
(5). In a glass vessel for microwave reactor, the N,N′,N -(benzene-
N,N′-(2-Methylbenzothiazole-4,6-diyl)diethanethioamide
1,2,4-triyl)triacetamide (2) (1.0 g, 4.0 mmol) was dissolved in dried
(9).
In a glass vessel for microwave reactor, the N,N′-(2-
THF (15 mL). Lawesson reagent (2.79 g, 6.9 mmol, 1.7 eq) was
added, and the reaction mixture was exposed to microwave
irradiation for 5 min at 120 C. After the reaction, a small amount of
methylbenzothiazole-4,6-diyl)diacetamide (8) (1.0 g, 3.8 mmol)
was dissolved in dried THF (15 mL). Lawesson reagent (1.7 g,
4.2 mmol, 1.1 eq) was added, and the reaction mixture was
exposed to microwave irradiation for 8 min at 110 C. THF was
evaporated, and the residue was dissolved in ethyl acetate
(50 mL). Organic layer was extracted with saturated solution of
ꢂ
ꢂ
fine black precipitate was filtered off, THF was evaporated, and the
crude product was purified by column chromatography on
aluminium oxide with ethyl acetate to obtain 0.24 g (29%) of
ꢂ
yellow solid, mp 229–232 C; IR (powder film): 3186 and 3147
NaHCO
3
(3 ꢁ 30mL) and with brine (2ꢁ 20mL), then dried over
and concentrated under vacuum. The crude product was
4
(
NH), 3030 (C -H), 2879 (C -H), 1881, 1739, 1627 and 1592
Na SO
2
Ar
sp3
ꢀ
1 1
(C ═C ), 1526 (NH), 1404 (C═S), 1293, 1179 cm ; H NMR
purified by column chromatography (silica gel; hexane:THF = 3:2)
Ar
Ar
ꢂ
(DMSO, 600 MHz), d = 12.27 (bs, 1H, NH), 11.54 (s, 1H, H-7),
to obtain 0.47g (42%) of yellow solid, mp 217–219 C; IR
8
.11 (s, 1H, NH), 7.43 (d, J= 8.5, 1H, H-4), 7.31 (dd, J=1.4,
(powder film): 3325 and 3282 (NH), 3201, 3136, 3084, 3066,
3033 (CAr-H), 2951 and 2921 (Csp3-H), 1616 and 1584 and 1559
(CAr═CAr), 1515 (NH), 1444, 1423, 1352 and 1330 (C═S), 1280,
1165 cm ; H NMR (DMSO, 300 MHz), d = 11.83 (s, 1H, NH),
11.80 (s, 1H, NH), 8.62 (d, J = 2.0, 1H, H-7), 8.23 (d, J = 2.0, 1H,
13
J= 8.4, 1H, H-5), 2.61 (s, 3H, CH ), 2.47 (s, 3H, CH ); C NMR
3
3
(
1
DMSO, 75 MHz), d = 203.7, 158.0, 139.3 (2 ꢁ C), 123.3 (2 ꢁ C),
ꢀ
ꢀ1
1
19.7, 144.5, 40.7, 20.3; HRMS (EI) m/z [M ꢀ H] Calcd for
10 11 3
C H N S: 204.0601; found: 204.0600.
2
-Methylbenzothiazole-4,6-diamine (7). To a solution of
-methyl-4,6-dinitrobenzothiazole (6) (2.5 g, 0.011 mol) in
ethanol (80%, 150 mL), hydrochloric acid (2.7 mL, 0.033 mol,
eq), and carbonyl-iron powder (3.5 g, 0.066 mol, 6 eq) were
added. The reaction mixture was sonificated (power 80%) for
8 min. The solid part was removed by filtration over a thick
H-5), 2.83 (s, 3H, CH
3
), 2.70 (s, 3H, CSCH
); C NMR (DMSO, 75MHz), d = 201.0, 199.7, 167.7,
145.0, 136.0, 135.5, 131.8, 118.9, 114.3, 35.1, 34.5, 19.8; HRMS
3
), 2.64 (s, 3H,
13
2
CSCH
3
+
3
(EI) m/z [M+ H] Calcd for C12 : 296.0344; found:
H N S
13 3 3
296.0333. Anal. Calcd for C12H N S : C, 48.78; H, 4.44; N,
14.22; S, 32.56. Found: C, 48,80; H, 4,46; N, 13,88; S, 32,40.
13 3 3
2
filter and washed with ethanol (80%, 200 mL). Ethanol was
2,3,8-Trimethylbisthiazolo[4,5-e;5,4-g]-1,3-benzothiazole
evaporated, and the residue was dissolved in ethyl acetate
(10). In a two-necked flask to a 20% aqueous solution of K
[Fe(CN) ] (12.9 mL, 3.23 g, 9.8 mmol, 7 eq), the solution of N,
3
(
50 mL). The precipitate that has arisen after the neutralisation
6
with saturated solution of Na CO (70 mL) was filtered off.
2
3
N′-(2-methylbenzothiazole-4,6-diyl)diethanethioamide (9) (0.4 g,
1.4 mmol) in 10% NaOH (9.1 mL, 1.01g, 25.2 mmol, 18 eq) was
added dropwise (1drop/1 min) in room temperature. The reaction
mixture was stirred for another 20 min, and then the precipitate
was filtered off. The aqueous layer was extracted with chloroform
Organic layer was once more extracted with the saturated
solution of Na CO (50 mL) then dried over Na SO4 and
2
3
2
concentrated under vacuum to obtain 1.69 g (89%) of brown
ꢂ
powder, mp 204–205 C; IR (powder film): 3441 and 3367 and
3
1
307 and 3194 (NH
2
), 3029 (CAr-H), 2923 (Csp3-H), 1603 and
(3 ꢁ 10 mL), dried over Na
2 4
SO , and concentrated under
574 (NH scissoring), 1519 (CAr═CAr), 1450, 1275 (C-N)
2
vacuum. The crude product, gained by filtration and
extraction, was purified by column chromatography (silica
gel; hexane:ethyl acetate:chloroform = 2:1:1) to obtain 0.29 g
ꢀ
1 1
cm ; H NMR (300 MHz, CDCl ), d = 6.46 (d, J = 1.9 Hz, 1H,
H-5), 6.09 (d, J = 1.9 Hz, 1H, H-7), 4.38 (bs, 2H, NH ), 3.63
3
2
1
3
ꢂ
(
bs, 2H, NH
2
), 2.71 (s, 3H, CH
3
); C NMR (CDCl
3
, 75 MHz),
(74%) of white solid, mp 223–225 C; IR (powder film):
d = 159.8, 145.1, 140.8 (2 ꢁ C), 137.8, 99.1, 96.0, 19.7; HRMS
2960 and 2920 and 2851 (Csp3-H), 2718, 2680, 2533, 1729,
+
ꢀ1
(
EI) m/z [M + H] Calcd for C
80.0530.
N,N′-(2-Methylbenzothiazole-4,6-diyl)diacetamide (8). To a
solution of 2-methylbenzothiazole-4,6-diamine (7) (2.5g,
8
H
9
N
3
S: 180.0590; found:
1558 and 1511 (CAr═CAr), 1432, 1360, 1349, 1167 cm
.
1
1
H NMR (CDCl
3
, 300 MHz), d = 2.99 (s, 3H, CH
3
), 2.97
1
3
(s, 3H, CH ), 2.94 (s, 3H, CH
3
3
);
C NMR (CDCl
3
,
75 MHz), d = 167.3, 167.0, 166.4, 144.7, 144.3, 144.0, 127.2,
+
0.014 mol) in dried THF (100 mL), acetanhydride (3.96 mL,
0.042 mol, 3 eq), and 4-dimethylaminopyridine (DMAP) (0.18 g,
10 mol%) were added. The mixture was stirred in room
125.9, 124.1, 20.2, 20.1 (2 ꢁ C); HRMS (EI) m/z [M + H]
Calcd for C12H N S : 292.0031; found: 292.0017. Anal.
9 3 3
Calcd for C12
9 3 3
H N S : C, 49.46; H, 3.11; N, 14.42; S, 33.01.
temperature for 20 h. THF was evaporated, and the residue was
Found: C, 49.86; H, 3.15; N, 14.06; S, 32.95.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

May 2013
Unsymmetrical Benzotristhiazole
567
2
,3,8-Tris(2-(4′-diphenylaminophenyl)ethen-1-yl)bisthiazolo
[3] Zyss, J.; Ledoux, I. Chem Rev 1994, 94, 77.
[4] Ogawa, K.; Kobuke, Y. Org Biomol Chem 2009, 7, 2241.
[
2
(
(
4,5-e;5,4-g]-1,3-benzothiazole (11). To the solution of compound
[5] Nielsen, C. B.; Arnbjerg, J.; Johnsen, M.; Jorgensen, M.;
,3,8-trimethylbisthiazolo[4,5-e;5,4-g]-1,3-benzothiazole 10
0.1g, 0.34 mmol) and 4-(N,N-diphenylamino)benzaldehyde
0.29 g, 1.05 mmol, 3.1eq) in DMSO (2mL), a 50% aqueous
solution of NaOH (0.05 mL, 0.1 g, 1.3 mmol, 3.9 eq) was added.
The reaction mixture was stirred for 24h by room temperature.
Another amount of 4-(N,N-diphenylamino)benzaldehyde (0.01 g,
.34 mmol, 1 eq) and 50% aqueous solution of NaOH (0.02 mL,
.04 g, 0.44 mmol, 1.3 eq) was added and stirred for 68h in room
temperature. The reaction mixture was poured into water
400mL), and the precipitate was filtered off. The crude product
Ogilby, P. R. J Org Chem 2009, 74, 9094.
6] Huang, P. H.; Shen, J. Y.; Pu, S. C.; Wen, Y. S.; Lin, J. T.;
Chou, P. T. M.; Yeh, C. P. J Mater Chem 2006, 16, 850.
7] Chung, S.; Rumi, J. M.; Alain, V.; Barlow, S.; Perry, J. W.;
[
[
Marder, S. R. J Am Chem Soc 2005, 127, 10844.
[8] Bordeau, G.; Lartia, R.; Metge, G.; Fiorini-Debuisschert,
C.; Charra, F.; Teulade-Fichou, M.-P. J Am Chem Soc 2008, 130,
0
0
1
6836.
9] Droumaguet, C. L.; Mongin, O.; Werts, M. H. V.; Blanchard-
Desce, M. Chem Commun 2005, 2802.
10] Katan, C.; Terenziani, F.; Mongin, O.; Werts, M. H. V.;
[
(
[
was purified by column chromatography (silica gel; chloroform)
to obtain 0.035g (10%) of red solid, mp 183–186 C; IR (powder
Porre`s, L.; Pons, T.; Mertz, J.; Tretiak, S.; Blanchard-Desce, M. J Phys
Chem A 2005, 109, 3024.
ꢂ
film): 3178, 3058, 3033 (C -H), 2960, 2929, 2851, 2765, 2612,
[11] Raposo, M. M. M.; Fonseca, A. M. C.; Castro, M. C. R.;
Belsley, M.; Cardoso, M. F. C.; Carvalho, L. M.; Coelho, P. J. Dyes Pigm
2011, 91, 62.
Ar
1
1
942, 1790, 1650, 1584 (C ═C ), 1504, 1487, 1328, 1314,
Ar Ar
1 1
ꢀ
269 (C-N), 1173, 1094, 953, 812, 749, 691 cm
, 600 MHz), d = 7.64 (d, J = 16.1, 1H, CH═), 7.58 (d,
J = 16.1, 1H, CH═), 7.50 (d, J = 16.1, 1H, CH═), 7.47–7.43 (m,
; H NMR
[
12] Raposo, M. M. M.; Castro, M. C. R.; Belsley, M.; Fonseca, A.
M. C. Dyes Pigm 2011, 91, 454.
13] Raposo, M. M. M.; Castro, M. C. R.; Fonseca, A. M. C.;
Belsley, M. Tetrahedron 2011, 67, 5189.
14] Costa, S. P. G.; Batista, R. M. F.; Cardoso, P.; Belsley, M.;
(
CDCl
3
[
3
1
C
C
1
ꢁ 2H, C -H), 7.45 (d, J = 16.0, 1H, CH═), 7.43 (d, J = 16.0,
Ar
H, CH═), 7.35 (d, J = 16.1, 1H, CH═), 7.32–7.28 (m, 6 ꢁ 2H,
[
Ar-H), 7.16–7.14 (m, 6 ꢁ 2H, CAr-H), 7.12–7.08 (m, 6 ꢁ 1H,
Raposo, M. M. M. Eur J Org Chem 2006, 3938.
[15] Ledoux, I.; Zyss, J.; Barni, E., Barolo, C., Diulgheroff, N.;
Quagliatto, P.; Viscardi, G. Synth Metals 2000, 115, 213.
1
3
Ar-H), 7.07–7.05 (m, 3 ꢁ 2H, CAr-H); C NMR (CDCl
3
,
50 MHz), d = 167.8, 167.7, 167.1, 149.3, 149.2, 149.0, 147.1
[
16] Varanasi, P. R.; Jen, A. K. Y.; Chandrasekhar, J.;
Namboothiri, I. N. N.; Rathna, A. J Am Chem Soc 1996, 118, 12443
17] Wang, Y. K.; Shu, Ch. F.; Breitung, E. M.; McMahon, R. J. J
Mater Chem 1999, 9, 1449.
18] Breitung, E.; Shu, Ch. F.; McMahon, R. J. J Am Chem Soc
2000, 122, 1154
[19] Sigmundová, I.; Zahradník, P.; Loos, D. Collection Czech
Chem Comm.
(
1
1
(
(
(
7
7
2ꢁ C), 147.08 (2ꢁ C), 147.03 (2 ꢁ C), 145.8, 145.4, 137.6,
37.4, 137.1, 129.5 (4ꢁ C), 129.43 (4 ꢁ C), 129.41 (4 ꢁ C),
28.9, 128.7, 128.6 (3 ꢁ C), 128.5 (4ꢁ C), 128.4, 126.3, 125.3
[
4ꢁ C), 125.2 (4ꢁ C), 125.1 (4ꢁ C), 124.9, 123.9 (2 ꢁ C), 123.8
2ꢁ C), 123.7 (2ꢁ C), 123.2, 122.3 (2 ꢁ C), 122.2 (2 ꢁ C), 122.1
2ꢁ C), 119.8, 119.6, 119.2. Anal. Calcd for C H N S : C,
[
6
9 48 6 3
8.38; H, 4.58; N, 7.95; S, 9.10. Found: C, 77.98; H, 4.81; N,
.57; S, 8.73.
[20] Zahradnik, P.; Magdolen P.; Zahradník, P. Tetrahedron Lett
2010, 51, 5819.
[
21] Hrobarikova, V.; Hrobarik, P.; Gajdos, P.; Fitilis, I.; Fakis, M.;
Persephonis, P.; Zahradnik, P. J Org Chem 2010, 75, 3053.
22] Hrobarik, P.; Sigmundova, I.; Zahradnik, P.; Kasak, P.; Arion,
V.; Franz, E.; Clays, K. J Phys Chem C 2010, 114, 22289.
[23] Hrobarik, P.; Sigmundova, I.; Zahradnik, P. Synthesis-
Stuttgart 2005, 600.
Acknowledgment. This work has been supported by the Slovak
Grant Agency APVV. (Grants APVV 0424–10 and APVV 0262–
[
1
0). A.F. would like to thank the Comenius University Grants.
(
No. UK/56/2010, UK/259/2009).
[24] Zajac, M.; Hrobarik, P.; Magdolen, P.; Foltinova, P.;
Zahradnik, P. Tetrahedron 2008, 64, 10605–10618;
[
[
[
[
25] Grandolini, G.; Martani, A. Gazz Chim Ital 1962, 92, 1150.
26] Roessler, A.; Boldt, P. Synthesis 1998, 980.
27] Stewart, J. J. P. J. Comput Chem 1989, 10, 209.
28] Fülöpová A. unpublished results.
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