Modifications of 5,12-dihydroindolo[3,2-a]carbazole scaffold via its regioselective C2,9-formylation and C2,9-acetylation

Article abstract of DOI:10.1016/j.tet.2019.07.015

The effective approaches for regioselective double formylation and acetylation of 5,12-dialkyl-6,7-diaryl-substituted 5,12-dihydroindolo[3,2-a]carbazoles by their treatment with dichloromethyl methyl ether in the presence of SnCl₄ or with acetyl chloride in the presence of AlCl₃ to afford the 2,9-diformyl or 2,9-diacetyl derivatives, respectively, were developed. Furthermore, new 2,9-bis(2,2-dicyanovinyl) derivatives were synthesized by the Knoevenagel condensation of diformyl-containing substrates with malononitrile, when new 2,9-bis(quinoxaline-2-yl)- and 2,9-bis(benzo[g]quinoxaline-2-yl) derivatives were formed via microwave-promoted oxidation of diacetyl-containing substrates with SeO₂ to the corresponding diglyoxals, followed by the reaction of these intermediates with o-phenylendiamine or 2,3-diaminonaphthalene, respectively. The basic optical and electrochemical properties of some 5,12-dihydroindolo[3,2-a]carbazoles were investigated.

Full text of DOI:10.1016/j.tet.2019.07.015

Accepted Manuscript
Modifications of 5,12-dihydroindolo[3,2-a]carbazole scaffold via its regioselective
C2,9-formylation and C2,9-acetylation
Nikita A. Kazin, Nadezhda S. Demina, Roman A. Irgashev, Ekaterina F. Zhilina,
Gennady L. Rusinov
PII:
S0040-4020(19)30757-4
https://doi.org/10.1016/j.tet.2019.07.015
TET 30457
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 31 May 2019
Revised Date: 3 July 2019
Accepted Date: 8 July 2019
Please cite this article as: Kazin NA, Demina NS, Irgashev RA, Zhilina EF, Rusinov GL, Modifications of
5,12-dihydroindolo[3,2-a]carbazole scaffold via its regioselective C2,9-formylation and C2,9-acetylation,
Tetrahedron (2019), doi: https://doi.org/10.1016/j.tet.2019.07.015.
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ACCEPTED MANUSCRIPT
Graphical abstract
Modifications of 5,12-dihydroindolo[3,2-a]carbazole scaffold
via its regioselective C2,9-formylation and C2,9-acetylation
Nikita A. Kazin, Nadezhda S. Demina, Roman A. Irgashev,* Ekaterina F. Zhilina, Gennady L. Rusinov
Postovsky Institute of Organic Synthesis, Ural Division, Russian Academy of Sciences, S. Kovalevskoy Str., 22,
Ekaterinburg, 620990, Russia
Corresponding author. Fax: +7 343 369 30 58;
e-mail: irgashev@ios.uran.ru

ACCEPTED MANUSCRIPT
Modifications of 5,12-dihydroindolo[3,2-a]carbazole scaffold via its
regioselective C2,9-formylation and C2,9-acetylation
Nikita A. Kazin,a,b Nadezhda S. Demina,a,b Roman A. Irgashev,a,b, Ekaterina F. Zhilina,a
Gennady L. Rusinova,b
a
Postovsky Institute of Organic Synthesis, Ural Division, Russian Academy of Sciences, S.
Kovalevskoy Str., 22, Ekaterinburg, 620990, Russia
*Corresponding author, e-mail: irgashev@ios.uran.ru
b Ural Federal University named after the First President of Russia B. N. Yeltsin, Mira Str., 19,
Ekaterinburg, 620002, Russia
Keywords: 5,12-Dihydroindolo[3,2-a]carbazoles; Formylation; Acetylation; Heteroacenes
_____________________________________________________________________________
ABSTRACT
The effective approaches for regioselective double formylation and acetylation of 5,12-dialkyl-
6,7-diaryl-substituted 5,12-dihydroindolo[3,2-a]carbazoles by their treatment with
dichloromethyl methyl ether in the presence of SnCl4 or with acetyl chloride in the presence of
AlCl3 to afford the 2,9-diformyl or 2,9-diacetyl derivatives, respectively, were developed.
Furthermore, new 2,9-bis(2,2-dicyanovinyl) derivatives were synthesized by the Knoevenagel
condensation of diformyl-containing substrates with malononitrile, when new 2,9-
bis(quinoxaline-2-yl)- and 2,9-bis(benzo[g]quinoxaline-2-yl) derivatives were formed via
microwave-promoted oxidation of diacetyl-containing substrates with SeO2 to the corresponding
diglyoxals, followed by the reaction of these intermediates with o-phenylendiamine or 2,3-
diaminonaphthalene, respectively. The basic optical and electrochemical properties of some
5,12-dihydroindolo[3,2-a]carbazoles were investigated.
_____________________________________________________________________________
1

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1. Introduction
Indolocarbazoles represent wide family consisting of five classes of isomeric ring-fused
heterocycles, which have attracted considerable research attention during past decades thanks to
a number of their valuable applications [1,2]. Indeed, derivatives of each of the five
indolocarbazole systems have been found to be useful for both medicinal chemistry and
materials science [1,2]. In the latter field, these π-conjugated fused systems, most often 5,11-
dihydroindolo[3,2-b]carbazoles [3], have been utilized for designing (electro)luminescent or
charge transport materials and light-harvesting dyes for organic electronics and photovoltaics
[2]. In turn, some 5,12-dihydroindolo[3,2-a]carbazoles (indolo[3,2-a]carbazoles) also proved to
be effective for use in organic light-emitting diodes (OLEDs) [4–6]. For instance, structures of
indolo[3,2-a]carbazole-based host materials ICDP, 4ICDPy and 4ICPPy (see ref. [5]) for
phosphorescent organic light-emitting diode (PhOLED) applications are shown in Figure 1.
Figure 1. Indolo[3,2-a]carbazole-based host materials for PhOLEDs
A number of effective methods for the construction of indolo[3,2-a]carbazoles has
previously been reported in the literature [7–16], while known options for further modification
are very limited. Taking into account π-excessive character of indolocarbazoles, one of the most
appropriate and attractive tools for framework modification is electrophilic aromatic substitution
(SEAr). In particular, we have previously described procedures for regioselective 2,8-formylation
[17,18], 2,8-acetylation [19], 2,8-aroylation [17,20] and 2,8-nitration [21] of 6,12-di(hetero)aryl-
5,11-dihydroindolo[3,2-b]carbazoles. Continuing our study, we report herein synthetic protocols
for double formylation and acetylation of 6,7-diaryl-substituted 5,12-dihydroindolo[3,2-
a]carbazoles, shown in Figure 2, and the further applications of the formyl- and acetyl-
substituted substrates for the construction of more π-extended derivatives.
Figure 2. The structure of studied 5,12-dihydroindolo[3,2-a]carbazoles
2

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2. Results and Discussion
2.1. Synthesis
There are few known ways for synthesis of indolo[3,2-a]carbazoles, bearing aromatic
moieties at C-6 and C-7 positions, such as palladium-catalyzed cascade reaction of 2,3-
unsubstituted indoles with 1,2-diarylacetylenes [22], palladium-catalyzed oxidative annulation of
2',3-unsubstituted 2,3'-biindoles with 1,2-diarylacetylenes [23] and condensation of 2,3-
unsubstituted indoles with 1,2-diarylethane-1,2-dione (benzils) under catalysis of p-
toluenesulfonic acid (p-TsOH) [24]. The latter protocol was chosen by us as the most attractive
one for preparing multigram-scale amounts of the desired indolo[3,2-a]carbazoles due to the
transition-metal-free process and commercially available starting materials. Unfortunately, using
the originally reported procedure [24], indolo[3,2-a]carbazole 3a (Ar = Ph) was obtained in 17%
yield instead of stated 62%, since, as soon as the solution of indole 1 and benzil 2a with p-TsOH
(20 mol%) in toluene was heated to a boil, there was a fast separation of a very viscous gum
from the reaction mixture, and further reaction had to proceed in the biphasic system.
Nevertheless, product 3a could be obtained in 77% yield, when this condensation was performed
by refluxing the reaction mixture for 10 h in acetonitrile solution instead of toluene one. The
reaction intermediates proved to be highly soluble in acetonitrile due to its greater polarity
compared to toluene, in contradiction to the desired product 3a, which precipitated from the hot
solution after 3-4 h. In the same manner, indolo[3,2-a]carbazoles 3b,c were prepared from indole
1 and 4,4'-disubstituted benzils 2b,c (Scheme 1, Table 1). The treatment of compounds 3 with
the appropriate alkyl halide (3 equiv) in the presence of NaH (6 equiv) in the DMSO-THF
mixture (2:8, v/v) allowed us to obtain derivatives 4a-g in 56-96% yields (Scheme 1, Table 1).
Scheme 1. Synthesis of indolo[3,2-a]carbazole derivatives 3 and 4
Table 1. Scope and yields of indolo[3,2-a]carbazoles 3 and 4
Entry Product 3 or 4
Ar
phenyl
4-methoxyphenyl
4-bromophenyl
Alk
Yield (%)
77 (17)a
80
1
-
-
-
3a
2
3
3b
3c
71
3

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4
5
6
7
8
phenyl
phenyl
n-C6H13
n-C4H9
C6H5CH2
C2H5
85
89
81
92
88
96
56
4a
4b
4cb
4d
4ec
4f
phenyl
phenyl
phenyl
CH3
9
10
4-methoxyphenyl
4-bromophenyl
n-C6H13
n-C6H13
4g
a Toluene was used as a solvent to perform the reaction.
b Benzylchloride was used to prepare compound 4c.
c Iodomethane was used to prepare compound 4e.
Further in this study, we focused our effort on finding suitable reaction conditions for the
regioselective formylation of substrates 4, that to obtain indolo[3,2-a]carbazole compounds with
aldehyde groups at the both terminal benzene rings of the fused frameworks. First, we tried to
perform formylation of indolo[3,2-a]carbazole 4a by the Vilsmeier–Haack protocol [25], that is
often used to prepare formyl derivatives of electron-rich (hetero)aromatic compounds. However,
the treatment of compound 4a with the Vilsmeier reagent (POCl3-DMF complex) gave a mixture
of several formyl-substituted products, which we failed to separate by crystallization or column
chromatography due to the close nature. At the same time, we succeeded to achieve
regioselective formylation of substrate 4a using the Rieche method [26,27], consisting in the
treatment of the starting compound with dichloromethyl methyl ether in the presence of SnCl4 in
dry CH2Cl2 solution at -20 °C for 1 h to form dialdehyde 5a as the single reaction product in
71% yield. Other 2,9-dialdehydes 5 were also prepared in the same manner in 55-86% yields
(Scheme 2, Table 2).
Scheme 2. Formylation of indolo[3,2-a]carbazoles 4 at C-2 and C-9 positions
Table 2. Scope and yields of 2,9-diformyl-substituted derivatives 5
Entry Substrate 4
Ar
Alk
n-C6H13
n-C4H9
C6H5CH2
C2H5
Product 5 Yield (%)
1
2
3
4
5
6
7
phenyl
phenyl
phenyl
phenyl
phenyl
71
68
55
59
61
78
86
4a
4b
4c
4d
4e
4f
5a
5b
5c
5d
5e
5f
CH3
4-methoxyphenyl n-C6H13
4-bromophenyl
n-C6H13
4g
5g
4

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In turn, the regioselective double acetylation of indolo[3,2-a]carbazoles 4 proceeded
smoothly by treatment with acetyl chloride in the presence of anhydrous AlCl3 in dry CH2Cl2
solution at 0 °C for 1 h, thus afforded 2,9-diacetyl-substiuted derivatives 6 in 71-88% yields
(Scheme 3, Table 3). The only exception was the N,N'-dibenzyl-substituted substrate 4c (Table 3,
entry 3), which undergone rapid decomposition under these reaction conditions and formed a
complex mixture of compounds. This fact can be explained by unwanted acetylation of the
benzyl groups of compound 4c as well as its debenzylation with AlCl3, similar to a previously
described reaction for N-benzylcarbazoles [28]. However, we also failed to perform acetylation
of 4c using acetyl chloride with milder Lewis acids, such as SnCl4 and TiCl4, as well as acetic
anhydride with BF3 etherate. The latter reaction conditions were previously used by us for
acetylation of 5,11-dihydroindolo[3,2-b]carbazole derivatives [19].
Scheme 3. Acetylation of indolo[3,2-a]carbazoles 4 at C-2 and C-9
Table 3. Scope and yields of 2,9-diacetyl-substituted derivatives 6
Entry Substrate 4
Ar
Alk
n-C6H13
n-C4H9
C6H5CH2
C2H5
Product 6 Yield (%)
1
2
3
4
5
6
7
phenyl
phenyl
phenyl
phenyl
phenyl
76
72
-
78
71
88
73
4a
4b
4c
4d
4e
4f
6a
6b
6c
6d
6e
6f
CH3
4-methoxyphenyl n-C6H13
4-bromophenyl n-C6H13
4g
6g
Notably, the structures of the diformyl- and diacetyl-substituted derivatives 5a-g and
1
6a,b,d-g is fully consistent with NMR data and elemental analysis. For instance, H NMR
spectra of products 5 and 6 contained characteristic signals of two non-equivalent formyl groups
at 9.5-9.6 ppm and 9.6-10.2 ppm or two non-equivalent acetyl group at 2.1-2.2 ppm and 2.7-2.8
ppm, respectively. However, to confirm unequivocally disposition of formyl and acetyl functions
in these molecules, we performed X-ray diffraction analysis for the single crystals of derivatives
5d and 6e; the results are shown in Figures 3 and 4.
5

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Figure 3. ORTEP diagram for the X-ray structure of 5d. Thermal ellipsoids of 50% probability
are shown
Figure 4. ORTEP diagram for the X-ray structure of 6e. Thermal ellipsoids of 50% probability
are shown.
We also showed usefulness of the formyl- and acetyl-functionalized substrates 5 and 6 as
the building blocks for the synthesis of π-extended indolo[3,2-a]carbazole compounds. To this
end, 2,9-dialdehydes 5a,b were treated with malononitrile in the presence of pyrrolidine acetate
(20 mol%) to obtain 2,9-bis(2,2-dicyanovinyl)-substituted indolo[3,2-a]carbazoles 7a and 7b in
83% and 76% yields (Scheme 4). At the same time, two 2,9-diacetyl derivatives 6 were utilized
by as us for the construction of 2,6,7,9-tetra(hetero)aryl-substituted indolo[3,2-a]carbazoles 8
6

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and 9, bearing quinoxaline-2-yl or benzo[g]quinoxaline-2-yl units at C-2 and C-9 positions,
respectively. Thus, the oxidation of substrates 6a,b with SeO2 in 1,4-dioxane solution at 150 °C
under microwave irradiation conditions for 30 min transformed both acetyl groups of 6 into
glyoxyloyl (COCHO) functions. The formed crude bis-glyoxal intermediates were further treated
with o-phenylendiamine or 2,3-diaminonaphthalene to afford desired products 8a,b and 9a,b in
59-77% yields, respectively (Scheme 4).
NC
O
NC
H
Alk
Alk
O
CN
NC
N
N
H
CH2(CN)2
N
Alk
N
Alk
pyrrolidine acetate /
DMF, 2 h, reflux
Ph
Ph
Ph
Ph
7a
, 83%
5a
, Alk = n-C6H13
7b
, 76%
5b, Alk = n-C4H9
N
N
CH3
O
1. SeO2 / 1,4-dioxane,
0.5 h, 150 °C, MW
2.
NH2
Alk
N
Alk
N
N
NH2
O
Ph
Ph
Ph
AcOH - 1,4-dioxane,
1 h, reflux
H3C
N
Ph
N
N
Alk
9a
O
O
SeO2
CH3
Alk
6a, Alk = n-C6H13
6b
8a
8b
, 59%; , 64%
9b
CHO
, Alk = n-C4H9
, 77%; , 59%
Scheme 4. Synthesis of π-extended indolo[3,2-a]carbazole derivatives 7a,b, 8a,b and 9a,b
2.2. Optical and electrochemical study
Cyclic voltammetry (CV) measurements of compounds 4a,f-g, 7a, 8a and 9a were
performed to study their electrochemical properties. The HOMO (Eꢀꢁꢂꢁ) and LUMO (Eꢃꢄꢂꢁ
)
(of compounds 8a and 9a) energy values were estimated from the onset potentials of the first
oxidation or reduction event according to the following equations:
EHOMO = – [E[onset, ox vs. Fc/Fc+]+ 5.1]
ELUMO = – [E[onset, red vs. Fc/Fc+]+ 5.1]
All the LUMO energy levels were also calculated from HOMO energy levels and the
optical band gaps (Eꢅꢆꢇꢈ) using equation:
Eꢃꢄꢂꢁ = Eꢀꢁꢂꢁ + Eꢆꢇꢈ
.
ꢅ
The obtained data are listed in Table 4.
Table 4. The electrochemical and optical characteristics of indolo[3,2-a]carbazoles derivatives
4a,f-g, 7a, 8a and 9a. All experiments were carried out in CH2Cl2 solution
7

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Eꢅꢆꢇꢈ, eV,a
Compound
E[onset, ox vs. Fc/Fc+], V
EHOMO, eV E[onset, red vs. Fc/Fc+], V
ELUMO, eV
3.24
3.24
3.23
0.28
0.25
0.34
0.65
0.39
0.39
-5.38
-5.35
-5.44
-5.75
-5.49
-5.49
-
-
-2.14
-2.11
-2.21
4a
4f
4g
7a
8a
9a
2.54
-3.21
2.79 (2.63)b
2.53 (2.33)b
-2.24
-1.94
-2.70 (-2.86)c
-2.96 (-3.16)c
a Estimated from the absorption spectra (Eꢅꢆꢇꢈ = 1240/λedge) [29].
b Electrochemical Eg was calculated from the equation Eg = ELUMO
– EHOMO
c Determined from the onset potential in cyclic voltammogram
The results of voltammetry shows that the oxidation potentials of the studied indolo[3,2-
a]carbazoles derivatives are quite sensitive to changes in the electron-donor properties of the
substituents. Thus, the introduction of an electron-withdrawing 2,2-dicyanovinyl fragment
(compound 7a) into indolo[3,2-a]carbazole core leads to a significant increase in Eonset, ox (~ 370
mV). The comparison of Eonset, ox of compound 4a with ones of 4f-g shows, that the introduction
of an electron-withdrawing p-bromo substituents increases the oxidation potential by 60 mV, at
the same time the introduction of an electron-donating methoxy groups gives a slight decrease.
For compounds 8a and 9a the reduction processes are observed, apparently related to the
heterocyclic moieties in the molecules.
The UV/visible absorption and photoluminescence spectra of compounds 4a, 4f, 4g, 7a, 8a
and 9a were recorded in CH2Cl2 solution (5·10-5M) at ambient temperature, and the results are
summarized in Tables 4 and 5.
All selected compounds are wide-bandgap semiconductors with Eꢅꢆꢇꢈ of ~3.24 eV for 4a,
4f-g and 2.50-2.80 eV for 7a, 8a and 9a. Thus, an increase in π-conjunction in indolo[3,2-
a]carbazole derivatives 7a, 8a, 9a leads to a significant decrease in the bandgap value.
Table 5. UV/Vis and photoluminescence data for 4a, 4f, 4g, 7a, 8a and 9a
Absorption
λmax, nm
Photoluminescence
Emission
λmax, nm
Compound
Excitation
λmax, nm
370,
ΦF, (±10) %
(ε, 103 M-1ꢀcm-1)
370 (28.6),
354 (17.2),
296 (89.9),
252 (74.3)
370 (15.8),
354 (9.7),
354,
296,
252
370,
354,
295,
280,
254
371,
355,
296,
250
429,
345,
294
397,
388
387
396
52a
4a
295 (50.2),
280 (44.5),
254 (39.1)
371 (17.3),
355 (10.6),
296 (54.9),
250 (48.6)
429 (63.9),
345 (34.9),
294 (49.3)
397 (49.3),
24a
55a
4f
4g
555
528
3b
7a
8a
33b
8

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300 (81.4),
238 (60.4)
423 (38.3),
309 (101.1),
267 (77.6),
232 (57.9)
238
423,
309,
267,
232
588
11b
9a
a Solution of quinine bisulfate in 0.1 N H2SO4 was used as a relative standard (ΦF = 52%, exλ = 300 nm) [30]
b Solution of 3-aminophthalimide in ethanol was used as a relative standard (ΦF = 60%, exλ = 400 nm) [31]
The various aryl substituents at C-6 ad C-7 positions of the indolo[3,2-a]carbazole core
have no effect on the absorption spectrum maxima in a series of compounds 4a, 4f, 4g (Figure
5). It can be caused by non-planar disposition of aryls due to steric factors. On the other hand,
there is a bathochromic shift of absorption bands in the spectra of indolo[3,2-a]carbazole
derivatives 7a, 8a, 9a due to the π-extended system compared with 4a one (Figure 6, also see
Supplementary Information).
Figure 5. UV/Vis spectra of compounds 4a, 4f, 4g
Figure 6. UV/Vis spectra of compounds 4a, 8a, 9a
9

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It was found that all selected compounds exhibit photoluminescent properties (Table 5).
The excitation spectra coincide with the absorption ones. The influence of the structure of
compounds 4a, 4f, 4g, 7a, 8a, 9a on the fluorescence spectra seems to be similar to that observed
for the absorption spectra. Thus, the fluorescence maxima of indolo[3,2-a]carbazoles (4a, 4f, 4g)
are in narrow range of values (380-400 nm). At the same time, the fluorescence spectrum
maxima of π-extended indolo[3,2-a]carbazole derivatives 7a, 8a, 9a (λmax = 520 – 590 nm) have
a significant bathochromic shift in respect to compound 4a (λmax = 388 nm).
3. Conclusion
In summary, we demonstrated that electrophilic aromatic substitution reactions are
effective synthetic tools for the primary functionalization of 5,12-dihydroindolo[3,2-a]carbazoles
framework on examples of its formylation and acetylation. Thus, the convenient procedures for
the synthesis of new 2,9-diformyl- and 2,9-diacetyl-substituted indolo[3,2-a]carbazoles with
aromatic fragments at C-6,7 positions were elaborated during this study. In addition, a few π-
extended derivatives of indolo[3,2-a]carbazole ring system, bearing 2,2-dicyanovinyl groups as
well as quinoxaline-2-yl or benzo[g]quinoxaline-2-yl parts at C-2 and C-9 positions, were
prepared starting from the above mentioned diformyl and diacetyl substrates to show synthetic
usefulness.
4. Experimental part
All reagents were purchased from commercial sources and used without further
purification.
Analytical studies were carried out using equipment of the Center for Joint Use
“Spectroscopy and Analysis of Organic Compounds” at the Postovsky Institute of Organic
Synthesis of the Russian Academy of Sciences (Ural Division). Melting points were determined
on combined heating stages and are uncorrected. Elemental analysis was carried on an automated
CHN analyzer. Mass spectrometry was performed using a high resolution Q-TOF LC-MS/MS
spectrometer. NMR measurements were performed on NMR spectrometers at 400 MHz and 500
1
MHz for H, 101 MHz, 126 MHz and 151 MHz for 13C spectra in DMSO-d6 or CDCl3 with
tetramethylsilane as an internal standard. The 13С NMR spectra of indolo[3,2-a]carbazoles 3b
and 3c could not be determined due to a poor solubility of these compounds in a majority of
deuterated solvents.
Cyclic voltammetry was carried out on a Metrohm Autolab PGSTAT128N potentiostat
with a standard three-electrode configuration. Typically, a three electrodes cell equipped with a
glass carbon working electrode, a Ag/AgNO3 (0.01M) reference electrode, and a glass carbon
10

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rod counter electrode was employed. The measurements were done in dichloromethane with
tetrabutylammonium hexafluorophosphate (0.1 M) as the supporting electrolyte under an argon
atmosphere at a scan rate of 100 mV/s. The potential of Ag/AgNO3 reference electrode was
calibrated by using the ferrocene/ferrocenium redox couple (Fc/Fc+), which has a known
oxidation potential of +5.1 eV.
Optical spectra were obtained in CH2Cl2 solution (5·10-5 M) at ambient temperature using a
Shimadzu UV-2600 double-beam UV/Vis spectrophotometer, a Varian Cary Eclipse
fluorescence spectrophotometer and a Hellma QS-101 high precision quartz cell.
5. General procedure for the synthesis of 6,7-bisaryl-5,12-dihydroindolo[3,2-
a]carbazoles (3)
p-Toluenesulfonic acid monohydrate (0.38 g; 20.00 mol%) was added to a solution of
indole 1 (2.92 g, 25.00 mmol) and the corresponding benzil 2a-c (10.00 mmol) in acetonitrile (25
ml), and the resulting mixture was refluxed for 10 hours. The solution turned red, and the formed
precipitate of desired product 3 was filtered off, washed with 3 × 5 ml of EtOH, and dried at 120
°C.
5.1 6,7-Diphenyl-5,12-dihydroindolo[3,2-a]carbazole (3а)
1
White powder (3.14 g, 77%), m.p. (321–322 °C). H NMR (400 MHz, DMSO-d6) δ 11.86
(s, 1H), 10.75 (s, 1H), 8.71 (d, J = 7.8 Hz, 1H), 7.61 (dd, J = 13.1, 8.0 Hz, 2H), 7.43 – 7.19 (m,
13H), 6.81 (td, J = 7.6, 7.1, 1.0 Hz, 1H), 6.53 (d, J = 8.0 Hz, 1H).
Compound 3a was previously described in the literature and its analytical data are identical
to the reported data [24].
5.2 6,7-Bis(4-methoxyphenyl)-5,12-dihydroindolo[3,2-a]carbazole (3b)
White powder (3.75 g, 80%), m.p. (> 360 °C). 1H NMR (500 MHz, DMSO-d6) δ 11.80 (s,
1H), 10.66 (s, 1H), 8.68 (d, J = 7.8 Hz, 1H), 7.60 (d, J = 8.0 Hz, 1H), 7.57 (d, J = 8.0 Hz, 1H),
7.37 (t, J = 7.5 Hz, 1H), 7.29 (t, J = 7.4 Hz, 1H), 7.26 – 7.17 (m, 5H), 6.97 – 6.88 (m, 4H), 6.84
(t, J = 7.5 Hz, 1H), 6.62 (d, J = 8.1 Hz, 1H), 3.79 (d, J = 15.3 Hz, 6H). Anal. Calcd for
C32H24N2O2: C, 82.0; H, 5.2; N, 6.0; Found: C, 81.9; H, 5.3; N, 6.1.
5.3 6,7-Bis(4-bromophenyl)-5,12-dihydroindolo[3,2-a]carbazole (3c)
White powder (4.02 g, 71%), m.p. (> 360 °C). 1H NMR (400 MHz, DMSO-d6) δ 11.93 (s,
1H), 10.87 (s, 1H), 8.71 (d, J = 7.8 Hz, 1H), 7.92 – 7.82 (m, 4H), 7.67 – 7.57 (m, 2H), 7.57 –
7.51 (m, 2H), 7.40 (t, J = 7.6 Hz, 1H), 7.36 – 7.22 (m, 4H), 6.89 (t, J = 7.5 Hz, 1H), 6.61 (d, J =
11

ACCEPTED MANUSCRIPT
7.9 Hz, 1H). Anal. Calcd for C30H18Br2N2: C, 63.6; H, 3.2; N, 4.95; Found: C, 63.9; H, 3.1; N,
4.9.
6. General procedure for the synthesis of 5,12-alkyl-6,7-diaryl-5,12-
dihydroindolo[3,2-a]carbazoles (4)
The corresponding alkyl halide (3.00 mmol) was added to the ice-cooled suspension of 3
(1.00 mmol) in a mixture of THF (8 ml) and DMSO (2 ml), and then sodium hydride (0.14 g,
6.00 mmol) was added in small portions. The resulting mixture was stirred for 3 hours at room
temperature. Then unreacted sodium hydride was decomposed with 2 ml of methanol, the
reaction mixture was diluted with water (20 ml), and the formed precipitate was filtered off and
recrystallized from DMF (8 ml), washed with 2 × 5 ml of EtOH and dried.
6.1 5,12-Dihexyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole (4a)
White powder (0.49 g, 85%), m.p. (119-120 °C). 1H NMR (500 MHz, Chloroform-d) δ 8.43 (t, J
= 8.1 Hz, 1H), 7.52 – 7.40 (m, 3H), 7.35 – 7.23 (m, 7H), 7.20 (dt, J = 6.9, 2.1 Hz, 5H), 6.86
(ddd, J = 8.0, 7.0, 1.0 Hz, 1H), 6.43 (dd, J = 8.0, 1.1 Hz, 1H), 4.94 – 4.88 (m, 2H), 3.74 – 3.67
(m, 2H), 2.28 – 2.18 (m, 2H), 1.62 – 1.56 (m, 2H), 1.52 – 1.31 (m, 7H), 1.23 – 1.12 (m, 2H),
1.12 – 1.02 (m, 2H), 0.95 – 0.88 (m, 3H), 0.84 – 0.75 (m, 5H). 13C NMR (126 MHz,
Chloroform-d) δ 141.1, 140.9, 140.3, 138.8, 138.2, 136.2, 135.9, 131.9, 130.3, 127.8, 127.3,
126.6, 126.5, 124.5, 124.1, 123.5, 122.4, 121.18, 121.16, 119.11, 119.07, 118.1, 115.0, 109.5,
109.0, 107.3, 46.5, 44.6, 31.6, 31.4, 30.9, 28.7, 26.5, 26.2, 22.6, 22.5, 14.01, 13.97. Anal. Calcd
for C42H44N2: C, 87.45; H, 7.7; N, 4.9; Found: C, 87.6; H, 7.8; N, 4.9.
6.2 5,12-Dibutyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole (4b)
White powder (0.46 g, 89%), m.p. (182-183 °C). 1H NMR (500 MHz, Chloroform-d) δ 8.43 (d, J
= 8.2 Hz, 1H), 7.49 – 7.38 (m, 3H), 7.36 – 7.23 (m, 6H), 7.17 (dt, J = 12.1, 6.9 Hz, 6H), 6.86 (t,
J = 7.6 Hz, 1H), 6.44 (d, J = 8.0 Hz, 1H), 4.90 (t, J = 8.0 Hz, 2H), 3.70 (t, J = 8.2 Hz, 2H), 2.19
(p, J = 7.8 Hz, 2H), 1.58 (h, J = 7.4 Hz, 2H), 1.42 (p, J = 7.8 Hz, 2H), 1.03 (t, J = 7.4 Hz, 3H),
0.82 (h, J = 7.5 Hz, 2H), 0.70 (t, J = 7.3 Hz, 3H). 13C NMR (126 MHz, Chloroform-d) δ 141.1,
140.9, 140.3, 138.8, 138.3, 136.2, 135.9, 131.9, 130.3, 127.8, 127.3, 126.6, 126.5, 124.5, 124.1,
123.5, 122.4, 121.2, 121.1, 119.12, 119.08, 118.1, 115.2, 109.5, 109.0, 107.4, 46.2, 44.4, 33.0,
30.8, 20.2, 19.8, 14.0, 13.6. Anal. Calcd for C38H36N2: C, 87.65; H, 7.0; N, 5.4; Found: C, 87.6;
H, 7.0; N, 5.3.
6.3 5,12-Dibenzyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole (4c)
12

ACCEPTED MANUSCRIPT
Beige powder (0.46 g, 81%), m.p. (283-284 °C). 1H NMR (400 MHz, Chloroform-d) δ 8.09 (d, J
= 8.2 Hz, 1H), 7.65 – 7.58 (m, 2H), 7.48 (t, J = 7.5 Hz, 2H), 7.43 – 7.35 (m, 1H), 7.33 – 7.15 (m,
9H), 7.15 – 6.97 (m, 7H), 6.97 – 6.84 (m, 3H), 6.55 (dd, J = 7.4, 2.1 Hz, 2H), 6.49 (d, J = 8.0 Hz,
1H), 6.12 (s, 2H), 5.07 (s, 2H). 13C NMR (101 MHz, Chloroform-d) δ 142.3, 141.3, 140.0, 138.7,
138.4, 137.84, 137.80, 137.4, 136.1, 131.8, 130.3, 129.2, 128.1, 127.8, 127.5, 127.1, 126.6,
126.5, 125.5, 124.9, 124.5, 124.1, 122.6, 121.2, 120.9, 119.8, 119.7, 118.8, 115.6, 109.9, 109.8,
107.5, 50.9, 47.9. (2 signal (2CAr) was not found due to overlapping peaks). Anal. Calcd for
C44H32N2: C, 89.8; H, 5.5; N, 4.8; Found: C, 89.7; H, 5.5; N, 4.6.
6.4 5,12-Diethyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole (4d)
1
White powder (4.27 g, 92%), m.p. (269–270 °C). H NMR (500 MHz, Chloroform-d) δ
8.50 (dt, J = 8.3, 0.9 Hz, 1H), 7.52 (dt, J = 8.2, 0.8 Hz, 1H), 7.50 – 7.42 (m, 2H), 7.36 – 7.31 (m,
2H), 7.31 – 7.15 (m, 11H), 6.88 (ddd, J = 8.0, 7.1, 1.0 Hz, 1H), 6.45 (dt, J = 7.9, 0.9 Hz, 1H),
5.04 (q, J = 7.2 Hz, 2H), 3.82 (q, J = 7.1 Hz, 2H), 1.85 (t, J = 7.2 Hz, 3H), 0.98 (t, J = 7.1 Hz,
3H).
Compound 4d was previously described in the literature and its analytical data are identical
to the reported data [24].
6.5 5,12-Dimethyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole (4e)
1
White powder (3.84 g, 88%), m.p. (314–315 °C). H NMR (400 MHz, Chloroform-d) δ
8.63 (d, J = 8.1 Hz, 1H), 7.48 (ddd, J = 7.0, 5.3, 2.7 Hz, 2H), 7.41 (d, J = 8.6 Hz, 1H), 7.33 (dtd,
J = 8.2, 7.0, 1.2 Hz, 2H), 7.32 – 7.14 (m, 4H), 6.90 (ddd, J = 8.1, 7.1, 1.1 Hz, 1H), 6.55 – 6.48
(m, 1H), 4.52 (s, 3H), 3.28 (s, 3H).
Compound 4e was previously described in the literature and its analytical data are identical
to the reported data [24].
6.6 5,12-Dihexyl-6,7-bis(4-methoxyphenyl)-5,12-dihydroindolo[3,2-a]carbazole (4f)
1
White powder (0.61 g, 96%), m.p. (178-179 °C). H NMR (400 MHz, DMSO-d6) δ 8.34
(d, J = 8.2 Hz, 1H), 7.53 (d, J = 8.2 Hz, 1H), 7.48 – 7.36 (m, 2H), 7.29 – 7.18 (m, 2H), 7.07 (d, J
= 8.3 Hz, 2H), 6.97 (d, J = 8.4 Hz, 2H), 6.82 – 6.74 (m, 1H), 6.74 (d, J = 8.5 Hz, 2H), 6.68 (d, J
= 8.5 Hz, 2H), 6.30 (d, J = 7.9 Hz, 1H), 4.90 (t, J = 7.9 Hz, 2H), 3.75 (s, 3H), 3.73 (s, 3H), 3.66
(q, J = 8.1, 7.5 Hz, 2H), 2.02 (p, J = 7.5 Hz, 2H), 1.51 – 1.39 (m, 2H), 1.38 – 1.22 (m, 6H), 1.16
(p, J = 7.0 Hz, 2H), 1.05 (p, J = 7.0 Hz, 2H), 0.89 – 0.73 (m, 8H). 13C NMR (126 MHz,
Chloroform-d) δ 158.2, 158.0, 141.1, 140.9, 138.6, 136.1, 136.0, 132.74, 132.66, 131.2, 131.0,
124.6, 124.0, 123.4, 122.3, 121.3, 121.2, 119.1, 119.0, 118.2, 115.5, 113.2, 112.7, 109.5, 108.9,
107.2, 55.1, 55.0, 46.5, 44.6, 31.6, 31.4, 30.9, 28.7, 26.5, 26.4, 22.6, 22.5, 13.99, 13.95. Anal.
Calcd for C44H48N2O2: C, 83.0; H, 7.6; N, 4.4; Found: C, 82.8; H, 7.8; N, 4.5.
13

ACCEPTED MANUSCRIPT
6.7 6,7-Bis(4-bromophenyl)-5,12-dihexyl-5,12-dihydroindolo[3,2-a]carbazole (4g)
Beige powder (0.41 g, 56%), m.p. (184-185 °C). 1H NMR (400 MHz, Chloroform-d) δ 8.42 (d, J
= 8.2 Hz, 1H), 7.54 – 7.46 (m, 2H), 7.46 – 7.39 (m, 3H), 7.39 – 7.30 (m, 4H), 7.16 – 7.08 (m,
2H), 7.12 – 7.00 (m, 2H), 6.97 – 6.89 (m, 1H), 6.49 (d, J = 7.9 Hz, 1H), 4.95 – 4.86 (m, 2H),
3.74 – 3.66 (m, 2H), 2.27 – 2.14 (m, 2H), 1.62 – 1.52 (m, 3H), 1.49 – 1.29 (m, 6H), 1.27 – 1.13
(m, 2H), 1.13 – 1.02 (m, 2H), 0.91 (t, J = 7.1 Hz, 3H), 0.88 – 0.78 (m, 5H). 13C NMR (126 MHz,
Chloroform-d) δ 141.1, 140.9, 139.0, 138.0, 137.6, 136.4, 134.2, 133.4, 132.0, 131.3, 130.6,
124.4, 124.1, 123.9, 122.4, 121.1, 120.97, 120.95, 119.38, 119.37, 119.36, 116.5, 114.8, 109.6,
109.2, 107.7, 46.5, 44.7, 31.6, 31.2, 30.8, 28.7, 26.5, 26.3, 22.6, 22.5, 13.98, 13.99. Anal. Calcd
for C42H42Br2N2: C, 68.7; H, 5.8; N, 3.8; Found: C, 68.7; H, 5.8; N, 4.1.
7. General procedure for the synthesis of 5,12-dialkyl-6,7-diaryl-5,12-
dihydroindolo[3,2-a]carbazole-2,9-dicarbaldehydes (5)
1,1-Dichloromethyl methyl ether (0.28 ml, 3.00 mmol) was added dropwise to the cooled
to -20 °C solution of 4 (1.00 mmol) and SnCl4 (0.47 ml, 4.00 mmol) in dichloromethane (20 ml),
and the resulting solution was incubated for 1 hour. The reaction mixture turned red. Then water
(50 ml) was added, and the mixture was stirred for 0.5 hours until discoloration. The organic
phase was separated, the solvent was distilled off, and the resulting residue of product 5 was
recrystallized from DMF (8-10 ml), washed with 2 × 5 ml of EtOH and dried at 120 °C.
7.1
5,12-Dihexyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-dicarbaldehyde
(5a)
White powder (0.45 g, 71%), m.p. (213-214 °C). 1H NMR (400 MHz, Chloroform-d) δ 10.17 (s,
1H), 9.59 (s, 1H), 8.97 (d, J = 1.4 Hz, 1H), 8.03 (dd, J = 8.5, 1.3 Hz, 1H), 7.94 (dd, J = 8.6, 1.6
Hz, 1H), 7.60 (d, J = 8.6 Hz, 1H), 7.54 (d, J = 8.6 Hz, 1H), 7.32 (ddd, J = 18.5, 4.2, 2.0 Hz, 5H),
7.26 – 7.15 (m, 5H), 6.80 (d, J = 1.5 Hz, 1H), 5.09 – 4.94 (m, 2H), 3.87 – 3.62 (m, 2H), 2.41 –
2.22 (m, 2H), 1.73 (p, J = 7.4 Hz, 2H), 1.53 – 1.30 (m, 6H), 1.26 – 1.12 (m, 2H), 1.14 – 1.01 (m,
2H), 0.91 (t, J = 7.1 Hz, 3H), 0.87 – 0.76 (m, 5H). 13C NMR (101 MHz, Chloroform-d) δ 191.8,
191.3, 144.5, 144.3, 139.24, 139.19, 137.7, 137.2, 136.4, 131.6, 129.9, 129.0, 128.9, 128.3,
127.6, 127.21, 127.17, 126.9, 126.5, 125.4, 123.94, 123.89, 120.9, 119.6, 116.2, 109.8, 109.4,
107.8, 46.7, 45.0, 31.7, 31.30, 31.27 , 28.7, 26.3, 26.1, 22.5, 22.4, 14.0, 13.9. Anal. Calcd for
C44H44N2O2: C, 83.5; H, 7.0; N, 4.4; Found: C, 83.7; H, 7.1; N, 4.6.
7.2
5,12-Dibutyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-dicarbaldehyde
(5b)
14

ACCEPTED MANUSCRIPT
White powder (0.39 g, 68%), m.p. (206-207 °C). 1H NMR (400 MHz, Chloroform-d) δ 10.16 (s,
1H), 9.58 (s, 1H), 8.97 (d, J = 1.5 Hz, 1H), 8.06 – 7.98 (m, 1H), 7.94 (dd, J = 8.6, 1.6 Hz, 1H),
7.59 (d, J = 8.7 Hz, 1H), 7.54 (d, J = 8.6 Hz, 1H), 7.42 – 7.13 (m, 10H), 6.80 (d, J = 1.6 Hz, 1H),
5.06 – 4.97 (m, 2H), 3.84 – 3.75 (m, 2H), 2.34 – 2.21 (m, 2H), 1.82 – 1.67 (m, 2H), 1.47 (p, J =
8.1 Hz, 2H), 1.10 (t, J = 7.3 Hz, 3H), 0.87 (h, J = 7.1, 6.6 Hz, 2H), 0.74 (t, J = 7.2 Hz, 3H). 13C
NMR (126 MHz, Chloroform-d) δ 191.8, 191.4, 144.6, 144.4, 139.3, 139.2, 137.6, 137.2, 136.4,
131.6, 129.9, 129.0, 128.9, 128.3, 127.6, 127.24, 127.18, 127.0, 126.6, 125.4, 124.0, 123.9,
121.0, 119.6, 116.2, 109.8, 109.5, 107.9, 46.6, 44.8, 33.4, 30.8, 20.0, 19.8, 14.0, 13.6. Anal.
Calcd for C40H36N2O2: C, 83.3; H, 6.3; N, 4.9; Found: , 83.3; H, 6.25; N, 4.8.
7.3 5,12-Dibenzyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-dicarbaldehyde
(5c)
1
White powder (0.37 g, 55%), m.p. (304-305 °C). H NMR (400 MHz, Chloroform-d) δ 9.62 (s,
1H), 9.48 (s, 1H), 8.50 (d, J = 1.4 Hz, 1H), 7.87 (ddd, J = 8.5, 5.1, 1.5 Hz, 2H), 7.59 – 7.48 (m,
4H), 7.42 (dd, J = 22.2, 7.9 Hz, 2H), 7.36 – 7.28 (m, 4H), 7.23 – 7.08 (m, 6H), 7.02 – 6.93 (m,
13
4H), 6.90 (d, J = 1.5 Hz, 1H), 6.55 – 6.47 (m, 2H), 6.23 (s, 2H), 5.14 (s, 2H). C NMR (101
MHz, Chloroform-d) δ 191.9, 191.5, 145.7, 144.8, 139.6, 138.9, 137.4, 137.2, 137.0, 136.69,
136.66, 131.5, 129.9, 129.63, 129.58, 128.4, 128.3, 128.2, 127.35, 127.27, 127.1, 127.0, 126.6,
126.1, 125.2, 124.7, 124.6, 124.5, 120.4, 120.3, 116.7, 110.5, 110.2, 107.9, 50.8, 48.3. Anal.
Calcd for C46H32N2O2: C, 85.7; H, 5.0; N, 4.3; Found: C, 85.5; H, 5.1; N, 4.6.
7.4
5,12-Diethyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-dicarbaldehyde
(5d)
White powder (0.32 g, 59%), m.p. (315-316 °C). 1H NMR (400 MHz, Chloroform-d) δ 10.18 (s,
1H), 9.60 (s, 1H), 9.06 (d, J = 1.4 Hz, 1H), 8.03 (dd, J = 8.6, 1.4 Hz, 1H), 7.96 (dd, J = 8.6, 1.6
Hz, 1H), 7.63 (d, J = 8.6 Hz, 1H), 7.56 (d, J = 8.5 Hz, 1H), 7.38 – 7.31 (m, 5H), 7.30 – 7.18 (m,
5H), 6.82 (d, J = 1.6 Hz, 1H), 5.14 (q, J = 7.2 Hz, 2H), 3.90 (q, J = 7.1 Hz, 2H), 1.96 (t, J = 7.2
13
Hz, 3H), 1.04 (t, J = 7.1 Hz, 3H). C NMR (126 MHz, Chloroform-d) δ 191.9, 191.6, 144.4,
144.1, 139.24, 139.18, 137.7, 137.2, 136.4, 131.5, 129.9, 129.2, 129.0, 128.3, 127.6, 127.3,
127.2, 127.0, 126.8, 125.4, 124.15, 124.09, 121.2, 119.6, 116.3, 109.8, 109.3, 107.9, 41.6, 39.5,
16.6, 14.1. Anal. Calcd for C36H28N2O2: C, 83.05; H, 5.4; N, 5.4; Found: C, 83.1; H, 5.5; N,
5.35.
7.5 5,12-Dimethyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-dicarbaldehyde
(5e)
White powder (0.30 g, 61%), m.p. (284-285 °C). 1H NMR (400 MHz, Chloroform-d) δ 10.16 (s,
1H), 9.62 (s, 1H), 9.16 (d, J = 1.5 Hz, 1H), 7.99 (ddd, J = 23.7, 8.6, 1.5 Hz, 2H), 7.55 (dd, J =
15

ACCEPTED MANUSCRIPT
27.7, 8.6 Hz, 2H), 7.36 (ddt, J = 5.6, 3.9, 2.2 Hz, 3H), 7.35 – 7.17 (m, 7H), 6.89 (d, J = 1.6 Hz,
1H), 4.65 (s, 3H), 3.35 (s, 3H). 13C NMR (126 MHz, Chloroform-d) δ 191.9, 191.7, 145.40,
145.36, 140.3, 139.0, 137.6, 137.1, 137.0, 132.0, 129.9, 129.0, 128.9, 128.3, 127.5, 127.3, 127.2,
126.8, 126.6, 125.4, 124.3, 124.0, 120.7, 119.8, 116.1, 109.5, 109.4, 107.7, 35.7, 33.5. Anal.
Calcd for C34H24N2O2: C, 82.9; H, 4.9; N, 5.7; Found: C, 82.8; H, 4.9; N, 5.6.
7.6
5,12-Dihexyl-6,7-bis(4-methoxyphenyl)-5,12-dihydroindolo[3,2-a]carbazole-2,9-
dicarbaldehyde (5f)
1
Cream powder (0.54 g, 78%), m.p. (225-226 °C). H NMR (500 MHz, DMSO-d6) δ 10.10 (s,
1H), 9.56 (s, 1H), 8.88 (d, J = 1.3 Hz, 1H), 7.97 (dd, J = 8.6, 1.3 Hz, 1H), 7.81 (dd, J = 8.6, 1.6
Hz, 1H), 7.76 (d, J = 8.6 Hz, 1H), 7.69 (d, J = 8.6 Hz, 1H), 7.18 – 7.12 (m, 2H), 7.08 – 7.01 (m,
2H), 6.90 – 6.84 (m, 2H), 6.81 – 6.77 (m, 2H), 6.76 (d, J = 1.5 Hz, 1H), 5.02 (t, J = 8.0 Hz, 2H),
3.83 (s, 3H), 3.81 – 3.74 (m, 5H), 2.10 (p, J = 8.0 Hz, 2H), 1.62 (p, J = 7.4 Hz, 2H), 1.44 – 1.26
13
(m, 6H), 1.21 – 1.14 (m, 2H), 1.12 – 1.04 (m, 1H), 0.84 (dt, J = 18.1, 7.2 Hz, 8H). C NMR
(126 MHz, Chloroform-d) δ 191.9, 191.3, 158.7, 158.6, 144.6, 144.3, 139.7, 137.4, 136.3, 132.4,
131.6, 130.9, 129.8, 129.0, 128.8, 127.2, 126.4, 125.4, 124.0, 123.7, 121.0, 119.7, 116.7, 113.8,
113.1, 109.8, 109.4, 107.8, 55.3, 55.2, 46.7, 45.0, 31.7 , 31.31, 31.32, 28.8, 26.28, 26.35, 22.6,
22.5, 14.0, 13.9. Anal. Calcd for C46H48N2O4: C, 79.7; H, 7.0; N, 4.0; Found: C, 79.8; H, 6.9; N,
4.1.
7.7
6,7-Bis(4-bromophenyl)-5,12-dihexyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
dicarbaldehyde (5g)
1
Cream powder (0.68g, 86%), m.p. (253-254 °C). H NMR (400 MHz, DMSO-d6) δ 10.12 (s,
1H), 9.60 (s, 1H), 8.92 (d, J = 1.4 Hz, 1H), 8.01 (dd, J = 8.5, 1.2 Hz, 1H), 7.85 – 7.82 (m, 2H),
7.75 (d, J = 8.6 Hz, 1H), 7.59 – 7.53 (m, 2H), 7.49 – 7.42 (m, 2H), 7.31 – 7.23 (m, 2H), 7.19 –
7.10 (m, 2H), 6.76 (d, J = 1.4 Hz, 1H), 5.06 (t, J = 7.9 Hz, 2H), 3.89 – 3.73 (m, 2H), 2.23 – 1.99
(m, 2H), 1.64 – 1.56 (m, 2H), 1.45 – 1.27 (m, 6H), 1.26 – 1.14 (m, 2H), 1.13 – 1.03 (m, 2H),
13
0.88 – 0.82 (m, 8H). C NMR (126 MHz, Chloroform-d) δ 191.6, 191.3, 144.6, 144.4, 139.1,
137.9, 136.6, 136.5, 135.6, 133.1, 131.7, 131.6, 131.0, 129.2, 129.1, 126.9, 126.6, 125.4, 124.1,
123.5, 121.7, 121.6, 120.8, 118.1, 116.0, 109.9, 109.7, 108.2, 46.8, 45.2, 31.7, 31.30, 31.26,
28.8, 26.3, 26.2, 22.55, 22.49, 13.98, 13.94. Anal. Calcd for C44H42Br2N2O2: C, 66.8; H, 5.35; N,
3.5; Found: C, 66.8; H, 5.4; N, 3.55.
8. General procedure for the synthesis of 1,1'-(5,12-dialkyl-6,7-diaryl-5,12-
dihydroindolo[3,2-a]carbazole-2,9-diyl)bis(ethan-1-one)s (6)
16

ACCEPTED MANUSCRIPT
Acetyl chloride (0.21 ml, 3.00 mmol) was added dropwise to the ice-cooled solution of 4
(1 mmol) and AlCl3 (0.53 g, 4.00 mmol) in dichloromethane (20 ml), and the resulting solution
was incubated for 1 hour. The reaction mixture turned red. Then 50 ml of water was added, and
the mixture was stirred for 0.5 hours until discoloration. The organic phase was separated, the
solvent was distilled off, and the resulting residue of product 6 was recrystallized from DMF (8-
10 ml), washed with 2 × 5 ml of EtOH and dried at 120 °C.
8.1 1,1'-(5,12-Dihexyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-diyl)bis(ethan-1-
one) (6a)
White powder (0.50 g, 76%), m.p. (208-209 °C). 1H NMR (400 MHz, Chloroform-d) δ 9.18 (d, J
= 1.6 Hz, 1H), 8.11 (dd, J = 8.7, 1.4 Hz, 1H), 8.05 (dd, J = 8.7, 1.7 Hz, 1H), 7.53 (d, J = 8.8 Hz,
1H), 7.45 (d, J = 8.7 Hz, 1H), 7.39 – 7.28 (m, 6H), 7.24 (dd, J = 4.5, 2.1 Hz, 4H), 6.96 (d, J = 1.7
Hz, 1H), 5.02 (t, J = 7.9 Hz, 2H), 3.92 – 3.60 (m, 2H), 2.77 (s, 3H), 2.27 – 2.15 (m, 2H), 2.19 (s,
3H), 1.65 (q, J = 7.7 Hz, 2H), 1.47 (p, J = 8.5 Hz, 2H), 1.42 – 1.28 (m, 4H), 1.27 – 1.14 (m, 2H),
13
1.09 (p, J = 6.9 Hz, 2H), 0.92 – 0.72 (m, 10H). C NMR (126 MHz, Chloroform-d) δ 197.8,
197.2, 143.69, 143.66, 139.7, 139.1, 137.9, 136.7, 136.4, 131.6, 130.1, 129.2, 129.0, 128.1,
127.5, 127.1, 127.0, 125.5, 123.92, 123.87, 123.8, 123.3, 120.8, 119.1, 116.2, 109.0, 108.8,
108.1, 46.7, 44.9, 31.7, 31.3, 31.2, 28.7, 26.7, 26.2, 26.1, 26.0, 22.5, 22.4, 13.99, 13.92. Anal.
Calcd for C46H48N2O2: C, 83.6; H, 7.3; N, 4.2; Found: C, 83.5; H, 7.4; N, 4.5.
8.2 1,1'-(5,12-Dibutyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-diyl)bis(ethan-1-
one) (6b)
White powder (0.44g, 72%), m.p. (257-258 °C). 1H NMR (500 MHz, Chloroform-d) δ 9.20 (d, J
= 1.6 Hz, 1H), 8.11 (dd, J = 8.8, 1.5 Hz, 2H), 8.05 (dd, J = 8.7, 1.7 Hz, 1H), 7.54 (d, J = 8.7 Hz,
1H), 7.45 (d, J = 8.7 Hz, 1H), 7.40 – 7.29 (m, 5H), 7.25 (s, 3H), 7.30 – 7.22 (m, 2H), 6.97 (d, J =
1.7 Hz, 1H), 5.03 (t, J = 7.9 Hz, 2H), 3.82 – 3.75 (m, 2H), 2.77 (s, 3H), 2.29 – 2.21 (m, 5H), 2.19
(s, 3H), 1.77 – 1.61 (m, 2H), 1.46 (p, J = 7.7 Hz, 2H), 1.06 (t, J = 7.3 Hz, 3H), 0.87 (q, J = 7.5
13
Hz, 2H), 0.74 (t, J = 7.3 Hz, 3H). C NMR (126 MHz, Chloroform-d) δ 197.8, 197.3, 143.7,
139.7, 139.1, 137.88, 137.86, 136.7, 136.4, 131.6, 130.1, 129.1, 129.0, 128.1, 127.5, 127.1,
127.0, 125.6, 123.91, 123.86, 123.7, 123.3, 120.8, 119.1, 116.2, 109.0, 108.8, 108.1, 46.5, 44.7,
33.4, 30.8, 26.7, 26.0, 20.0, 19.8, 14.0, 13.6. Anal. Calcd for C42H40N2O2: C, 83.4; H, 6.7; N,
4.6; Found: C, 83.3; H, 6.7; N, 4.8.
8.3
1,1'-(5,12-Diethyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
diyl)bis(ethan-1-one) (6d)
17

ACCEPTED MANUSCRIPT
1
White powder (0.37 g, 78%), m.p. (264-265 °C). H NMR (400 MHz, Chloroform-d) δ
9.26 (d, J = 1.6 Hz, 1H), 8.14 (dd, J = 8.7, 1.5 Hz, 1H), 8.07 (dd, J = 8.6, 1.8 Hz, 1H), 7.57 (dd, J
= 8.7, 4.4 Hz, 1H), 7.48 (d, J = 8.7 Hz, 1H), 7.42 – 7.26 (m, 5H), 7.30 – 7.17 (m, 5H), 6.98 (d, J
= 1.7 Hz, 1H), 5.12 (q, J = 7.2 Hz, 2H), 3.88 (q, J = 7.1 Hz, 2H), 2.79 (s, 3H), 2.20 (s, 3H), 2.02
13
– 1.90 (m, 3H), 1.04 (q, J = 7.2 Hz, 3H). C NMR (151 MHz, Chloroform-d) δ 197.9, 197.5,
143.5, 143.4, 139.7, 139.0, 138.0, 136.8, 136.5, 131.6, 130.1, 129.3, 129.2, 128.3, 127.6, 127.3,
127.1, 125.5, 124.2, 124.0, 123.9, 123.5, 120.9, 119.2, 116.2, 109.0, 108.8, 108.1, 41.6, 39.4,
26.8, 26.1, 16.6, 14.1. Anal. Calcd for C38H32N2O2: C, 83.2; H, 5.9; N, 5.1; Found: C, 83.3; H,
5.75; N, 5.15.
8.4
1,1'-(5,12-Dimethyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
diyl)bis(ethan-1-one) (6e)
1
White powder (0.37 g, 71%), m.p. (323-324 °C). H NMR (400 MHz, Chloroform-d) δ
9.37 (d, J = 1.6 Hz, 1H), 8.12 (dd, J = 8.7, 1.6 Hz, 1H), 8.08 (dd, J = 8.6, 1.7 Hz, 1H), 7.52 (d, J
= 8.7 Hz, 1H), 7.43 (d, J = 8.7 Hz, 1H), 7.40 – 7.35 (m, 2H), 7.32 – 7.24 (m, 8H), 7.04 (d, J =
1.7 Hz, 1H), 4.63 (s, 3H), 3.34 (s, 3H), 2.78 (s, 3H), 2.22 (s, 3H). 13C NMR (101 MHz,
Chloroform-d) δ 197.9, 197.5, 144.7, 144.5, 140.1, 139.5, 137.9, 137.2, 136.5, 132.0, 130.1,
129.3, 129.1, 128.2, 127.5, 127.14, 127.11, 125.5, 124.3, 123.9, 123.7, 123.5, 120.5, 119.3,
116.2, 108.9, 108.7, 107.9, 35.6, 33.3, 26.7, 26.0. Anal. Calcd for C36H28N2O2: C, 83.05; H, 5.4;
N, 5.4; Found: C, 83.1; H, 5.4; N, 5.2.
8.5 1,1'-(6,7-Bis(4-bromophenyl)-5,12-dihexyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
diyl)bis(ethan-1-one) (6f)
White powder (0.72 g, 88%), m.p. (266-267 °C). 1H NMR (400 MHz, DMSO-d6) δ 9.05 (d, J =
1.6 Hz, 1H), 8.10 (dd, J = 8.7, 1.4 Hz, 1H), 7.89 (dd, J = 8.7, 1.7 Hz, 1H), 7.68 (d, J = 8.8 Hz,
1H), 7.63 (d, J = 8.8 Hz, 1H), 7.61 – 7.53 (m, 2H), 7.50 – 7.39 (m, 2H), 7.33 – 7.26 (m, 2H),
7.21 – 7.12 (m, 2H), 6.78 (d, J = 1.7 Hz, 1H), 5.02 (t, J = 7.7 Hz, 2H), 3.87 – 3.70 (m, 2H), 2.71
(s, 3H), 2.19 (s, 3H), 2.07 (d, J = 8.5 Hz, 2H), 1.57 (t, J = 7.8 Hz, 2H), 1.39 (d, J = 16.0 Hz, 2H),
13
1.32 – 1.16 (m, 6H), 1.14 – 1.02 (m, 2H), 0.84 (td, J = 7.0, 3.7 Hz, 8H). C NMR (101 MHz,
Chloroform-d) δ 197.5, 197.1, 143.67, 143.66, 138.9, 138.4, 136.7, 136.6, 135.1, 133.1, 131.8,
131.6, 131.0, 129.4, 129.2, 125.8, 124.2, 123.8, 123.4, 122.9, 121.6, 121.5, 120.7, 117.5, 116.1,
109.2, 109.0, 108.5, 46.7, 45.1, 31.6, 31.3, 31.2, 28.8, 26.7, 26.25, 26.18, 25.8, 22.50, 22.45,
13.96, 13.94. Anal. Calcd for C46H46Br2N2O2: C, 67.5; H, 5.7; N, 3.4; Found: C, 67.5; H, 5.7; N,
3.6.
18

ACCEPTED MANUSCRIPT
8.6 1,1'-(6,7-Bis(4-methoxyphenyl)-5,12-dihexyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
diyl)bis(ethan-1-one) (6g)
White powder (0.53 g, 73%), m.p. (208-209 °C). 1H NMR (500 MHz, DMSO-d6) δ 9.05 (d, J =
1.6 Hz, 1H), 8.08 (dd, J = 8.7, 1.4 Hz, 1H), 7.87 (dd, J = 8.7, 1.7 Hz, 1H), 7.64 (d, J = 8.7 Hz,
1H), 7.59 (d, J = 8.7 Hz, 1H), 7.23 – 7.17 (m, 2H), 7.12 – 7.06 (m, 2H), 6.96 – 6.89 (m, 2H),
6.84 – 6.77 (m, 3H), 5.02 (t, J = 7.8 Hz, 2H), 3.81 (s, 3H), 3.80 – 3.68 (m, 5H), 2.71 (s, 3H), 2.15
(s, 3H), 2.06 (q, J = 7.8 Hz, 2H), 1.56 (q, J = 7.7 Hz, 2H), 1.39 (d, J = 6.6 Hz, 2H), 1.35 – 1.13
(m, 6H), 1.13 – 1.03 (m, 2H), 0.93 – 0.75 (m, 8H). 13C NMR (101 MHz, Chloroform-d) δ 197.7,
197.2, 158.56, 158.52, 143.7, 139.5, 136.98, 136.92, 136.3, 132.5, 132.1, 131.1, 130.1, 129.1,
128.9, 125.5, 124.0, 123.8, 123.7, 123.4, 120.8, 119.2, 116.8, 113.7, 113.0, 109.0, 108.8, 108.1,
55.3, 55.1, 46.7, 44.9, 31.7, 31.3, 31.2, 28.7, 26.7, 26.3, 26.2, 25.9, 22.48, 22.47, 13.98, 13.91.
Anal. Calcd for C48H52N2O4: C, 80.0; H, 7.3; N, 3.9; Found: C, 79.9; H, 7.25; N, 3.9.
9. General procedure for the synthesis of 2,2'-((5,12-dialkyl-6,7-diaryl-5,12-
dihydroindolo[3,2-a]carbazole-2,9-diyl)bis(methaneylylidene))dimalononitriles (7)
Dicarbaldehyde 5 (0.50 mmol) and malononitrile (0.13 g, 2.00 mmol) were added in a
mixture of DMF (3 ml), AcOH (2 ml) and pyrrolidine (0.17 ml, 2.00 mmol), the resulting
solution was refluxed for 2 hours. Then the reaction mixture was cooled, and the formed
precipitate was filtered off and crystallized from DMF (3 ml), washed with 2 × 2 ml EtOH and
dried at 120 °C to give the desired product 7.
9.1
2,2'-((5,12-Dihexyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
diyl)bis(methaneylylidene))dimalononitrile (7a)
Orange powder (0.30 g, 83%), m.p. (253-254 °C). 1H NMR (500 MHz, Chloroform-d) δ 8.90 (d,
J = 1.7 Hz, 1H), 8.38 (dd, J = 8.9, 1.9 Hz, 1H), 8.14 (dd, J = 8.8, 1.6 Hz, 1H), 7.91 (s, 1H), 7.64
(d, J = 8.9 Hz, 1H), 7.55 (d, J = 8.8 Hz, 1H), 7.40 – 7.31 (m, 3H), 7.30 – 7.26 (m, 6H), 7.20 –
7.12 (m, 2H), 6.44 (d, J = 1.9 Hz, 1H), 5.05 (t, J = 7.4 Hz, 2H), 3.83 – 3.70 (m, 2H), 2.16 – 2.01
(m, 2H), 1.53 – 1.44 (m, 2H), 1.44 – 1.36 (m, 2H), 1.33 – 1.16 (m, 6H), 1.15 – 1.04 (m, 2H),
13
0.90 – 0.77 (m, 8H). C NMR (101 MHz, Chloroform-d) δ 160.5, 160.1, 144.5, 144.4, 139.5,
138.7, 137.8, 137.0, 136.3, 131.4, 129.7, 129.4, 128.4, 127.74 , 127.66, 127.56, 127.51, 127.1,
124.3, 124.0, 123.01, 122.96, 121.5, 120.5, 116.7, 115.0, 114.9, 114.1, 113.7, 110.73, 110.72,
107.8, 46.6, 45.2, 31.4, 31.2, 30.6, 28.9, 26.4, 26.0, 22.45, 22.38, 13.87, 13.86. Anal. Calcd for
C50H44N6: C, 82.4; H, 6.1; N, 11.5; Found: C, 82.3; H, 5.9; N, 11.7.
19

ACCEPTED MANUSCRIPT
9.2
2,2'-((5,12-Dibutyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole-2,9-
diyl)bis(methaneylylidene))dimalononitrile (7b)
Orange powder (0.51 g, 76%), m.p. (281-282 °C). 1H NMR (500 MHz, Chloroform-d) δ 8.95 (d,
J = 1.7 Hz, 1H), 8.39 (dd, J = 9.0, 1.9 Hz, 1H), 8.13 – 8.07 (m, 1H), 7.91 (s, 1H), 7.64 (d, J = 9.0
Hz, 1H), 7.55 (d, J = 8.8 Hz, 1H), 7.41 – 7.27 (m, 3H), 7.30 – 7.25 (m, 6H), 7.20 – 7.14 (m, 2H),
6.44 (d, J = 1.9 Hz, 1H), 5.08 (t, J = 7.2 Hz, 2H), 3.83 – 3.76 (m, 1H), 2.10 – 2.03 (m, 2H), 1.51
– 1.43 (m, 2H), 1.39 (p, J = 7.5 Hz, 2H), 0.95 (t, J = 7.4 Hz, 3H), 0.86 (q, J = 7.5 Hz, 2H), 0.75
13
(t, J = 7.2 Hz, 3H). C NMR (126 MHz, Chloroform-d) δ 160.6, 160.2, 144.59, 144.56, 139.7,
138.7, 137.9, 137.1, 136.4, 131.5, 129.7, 129.4, 128.5, 127.9, 127.7, 127.60, 127.57, 126.9,
124.4, 124.1, 123.07, 123.05, 121.7, 120.6, 116.8, 115.1, 114.9 , 114.2, 113.8, 110.8, 110.7,
107.9, 46.5, 45.1, 32.8, 31.0, 20.2, 19.8, 13.9, 13.5. Anal. Calcd for C46H36N6: C, 82.1; H, 5.4; N,
12.5; Found: C, 82.1; H, 5.4; N, 12.4.
10. General procedure for the synthesis of 5,12-dialkyl-6,7-diphenyl-2,9-
di(quinoxalin-2-yl)-5,12-dihydroindolo[3,2-a]carbazoles
(8)
and
2,9-
bis(benzo[g]quinoxalin-2-yl)-5,12-dialkyl-6,7-diphenyl-5,12-dihydroindolo[3,2-
a]carbazoles (9)
Diacetyl derivative 6 (0.25 mmol), SeO2 (0.06 g, 0.50 mmol), 1,4-dioxane (5 ml), and H2O
(50 ꢁl) were placed in a 10 ml microwave reaction vial. The resulting mixture was irradiated for
0.5 h (200 W) at 150 °C. Then the black precipitate of elemental Se was filtered off, and the
bright yellow filtrate was used in the next stage. o-Phenylenediamine (0.08 g, 0.7 mmol) or 2,3-
diaminonaphthalene (0.12 g, 0.75 mmol) and glacial AcOH (0.75 ml) were added to the
previously obtained filtrate, and the resulting solution was refluxed for an hour. After cooling the
reaction mixture, the precipitate of product 8 or 9 was separated by filtration and recrystallized
from DMF (10 ml), washed with 2 × 2 ml EtOH and dried at 120 ° C.
10.1
5,12-Dihexyl-6,7-diphenyl-2,9-di(quinoxalin-2-yl)-5,12-dihydroindolo[3,2-
a]carbazole (8a)
Yellow powder (0.49 g, 59%), m.p. (220-221 °C). 1H NMR (500 MHz, Chloroform-d) δ 9.49 (s,
1H), 9.43 (d, J = 1.6 Hz, 1H), 8.80 (s, 1H), 8.38 (dd, J = 8.6, 1.8 Hz, 1H), 8.27 (dd, J = 8.6, 1.5
Hz, 1H), 8.21 (dd, J = 8.2, 1.4 Hz, 2H), 8.15 (dd, J = 8.3, 1.4 Hz, 1H), 8.04 (td, J = 8.8, 1.4 Hz,
2H), 7.85 – 7.56 (m, 6H), 7.50 – 7.19 (m, 10H), 7.13 (d, J = 1.8 Hz, 1H), 5.14 (t, J = 7.9 Hz,
2H), 3.84 – 3.77 (m, 2H), 2.32 (t, J = 7.8 Hz, 2H), 1.68 (dt, J = 15.3, 7.7 Hz, 2H), 1.54 – 1.48
(m, 2H), 1.31 (q, J = 7.8 Hz, 2H), 1.27 – 1.06 (m, 6H), 0.90 – 0.79 (m, 5H), 0.71 (t, J = 7.3 Hz,
3H). 13C NMR (126 MHz, Chloroform-d) δ 152.8, 152.3, 143.6, 143.2, 142.5, 142.3, 142.24,
20

ACCEPTED MANUSCRIPT
142.16, 141.1, 140.8, 140.0, 139.0, 138.2, 136.7, 136.5, 131.7, 130.2, 130.0, 129.7, 129.3, 129.2,
129.1, 128.8, 128.5, 128.3, 128.1, 127.50, 127.48, 127.10, 127.07, 124.5, 123.8, 123.4 122.6,
121.9, 120.6, 118.8, 115.9, 109.9, 107.9, 46.7, 44.9, 31.6, 31.33, 31.29, 28.7, 26.5, 26.2, 22.44,
22.38, 13.9, 13.8. (2 signal (2CAr) was not found due to overlapping peaks). Anal. Calcd for
C58H52N6: C, 83.6; H, 6.3; N, 10.1; Found: C, 83.75; H, 6.3; N, 10.1.
10.2
5,12-Dibutyl-6,7-diphenyl-2,9-di(quinoxalin-2-yl)-5,12-dihydroindolo[3,2-
a]carbazole (8b)
Yellow powder (0.60 g, 77%), m.p. (175-176 °C). 1H NMR (500 MHz, Chloroform-d) δ 9.50 (s,
1H), 9.44 (d, J = 1.6 Hz, 1H), 8.81 (s, 1H), 8.39 (dd, J = 8.6, 1.8 Hz, 1H), 8.29 (dd, J = 8.6, 1.5
Hz, 1H), 8.21 (dd, J = 8.3, 1.4 Hz, 2H), 8.16 (dd, J = 8.3, 1.4 Hz, 1H), 8.09 – 7.98 (m, 2H), 7.86
– 7.58 (m, 6H), 7.50 – 7.21 (m, 10H), 7.14 (d, J = 1.8 Hz, 1H), 5.17 (t, J = 7.9 Hz, 2H), 3.95 –
3.68 (m, 2H), 2.35 (p, J = 7.9 Hz, 2H), 1.77 (q, J = 7.6 Hz, 2H), 1.51 (p, J = 8.0 Hz, 2H), 1.00 (t,
J = 7.4 Hz, 3H), 0.90 (h, J = 7.3 Hz, 2H), 0.76 (t, J = 7.3 Hz, 3H). 13C NMR (101 MHz,
Chloroform-d) δ 152.7, 152.0, 143.4, 143.0, 142.9, 142.4, 142.2, 141.0, 139.9, 139.1, 138.2,
136.7, 136.5, 131.7, 130.24, 130.18, 130.0, 129.1, 129.0, 128.9, 128.71, 128.68, 128.5, 128.3,
128.0, 127.9, 127.5, 127.1, 127.0, 124.5, 123.9, 123.64, 123.57, 122.5, 121.9, 120.8, 118.9,
115.9, 110.0, 108.0, 46.4, 44.7, 33.5, 30.9, 20.1, 19.8, 14.1, 13.6. (2 signal (2CAr) was not found
due to overlapping peaks). Anal. Calcd for C54H44N6: C, 83.5; H, 5.7; N, 10.8; Found: C, 83.4;
H, 5.7; N, 11.0.
10.3
2,9-Bis(benzo[g]quinoxalin-2-yl)-5,12-dihexyl-6,7-diphenyl-5,12-dihydroindolo[3,2-
a]carbazole (9а)
1
Dark orange powder (0.60 g, 64%), m.p. (282-283 °C). H NMR (500 MHz, Chloroform-d) δ
9.57 (s, 1H), 9.51 (d, J = 1.6 Hz, 1H), 8.83 (s, 1H), 8.76 (s, 1H), 8.71 (s, 1H), 8.58 (d, J = 5.3 Hz,
2H), 8.49 (dd, J = 8.6, 1.8 Hz, 1H), 8.35 (dd, J = 8.5, 1.5 Hz, 1H), 8.15 (d, J = 8.2 Hz, 2H), 8.07
(t, J = 8.6 Hz, 2H), 7.72 (d, J = 8.7 Hz, 1H), 7.65 – 7.42 (m, 8H), 7.41 – 7.32 (m, 4H), 7.33 –
7.25 (m, 3H), 7.17 (d, J = 1.8 Hz, 1H), 5.20 (t, J = 7.9 Hz, 2H), 3.82 (t, J = 8.2 Hz, 2H), 2.41 –
2.34 (m, 2H), 1.76 (t, J = 7.8 Hz, 2H), 1.57 – 1.47 (m, 2H), 1.37 (q, J = 7.8 Hz, 2H), 1.27 – 1.07
13
(m, 6H), 0.91 – 0.81 (m, 5H), 0.71 (t, J = 7.4 Hz, 3H). C NMR (126 MHz, Chloroform-d) δ
152.3, 151.2, 144.7, 144.1, 142.5, 142.3, 139.9, 139.0 , 138.8, 138.1, 137.8, 137.1, 136.6, 136.4,
134.2, 134.0, 133.2, 133.0, 131.7, 130.3, 128.5, 128.34, 128.26, 128.2, 127.9, 127.5, 127.4,
127.2, 127.1, 127.0, 126.8, 126.7, 126.4, 126.2, 124.3, 124.0, 122.7, 121.8, 121.0, 118.9, 115.8,
110.1, 109.9, 107.9, 46.6, 45.0, 31.7, 31.38, 31.35, 28.8, 26.5, 26.2, 22.50, 22.47, 14.0, 13.9. (4
21

ACCEPTED MANUSCRIPT
signal (4CAr) was not found due to overlapping peaks). Anal. Calcd for C66H56N6: C, 84.95; H,
6.05; N, 9.0; Found: C, 84.8; H, 6.2; N, 8.9.
10.4 2,9-Bis(benzo[g]quinoxalin-2-yl)-5,12-dibutyl-6,7-diphenyl-5,12-dihydroindolo[3,2-
a]carbazole (9b)
1
Orange powder (0.52 g, 59%), m.p. (319-320 °C). H NMR (500 MHz, Chloroform-d) δ
9.58 (s, 1H), 9.53 (d, J = 1.5 Hz, 1H), 8.84 (s, 1H), 8.76 (s, 1H), 8.72 (s, 1H), 8.59 (d, J = 6.2 Hz,
2H), 8.50 (dd, J = 8.5, 1.8 Hz, 1H), 8.36 (dd, J = 8.7, 1.5 Hz, 1H), 8.16 (dd, J = 7.7, 5.6 Hz, 2H),
8.08 (t, J = 8.1 Hz, 2H), 7.74 (d, J = 8.7 Hz, 1H), 7.66 – 7.42 (m, 8H), 7.42 – 7.26 (m, 7H), 7.19
(d, J = 1.7 Hz, 1H), 5.22 (t, J = 7.9 Hz, 2H), 3.88 – 3.80 (m, 2H), 2.40 (t, J = 7.7 Hz, 2H), 1.83
(q, J = 7.6 Hz, 2H), 1.57 – 1.45 (m, 2H), 1.04 (t, J = 7.4 Hz, 3H), 0.91 (m, 2H), 0.77 (t, J = 7.3
Hz, 3H). 13C NMR (101 MHz, Chloroform-d) δ 152.1, 151.0, 144.6, 143.9, 142.6, 139.8, 139.7,
139.2, 138.1, 138.0, 137.9, 136.80, 136.78, 136.51, 136.48, 134.6, 134.43, 134.38, 131.8, 131.7,
130.3, 128.9, 128.62, 128.57, 128.43, 128.39, 127.6, 127.4, 127.2, 127.0, 126.7, 124.47, 124.45,
124.3, 122.9, 121.8, 119.2, 115.9, 115.8, 110.6, 110.5, 110.3, 110.1, 108.0, 46.6, 44.8, 33.5,
30.9, 20.2, 19.9, 14.2, 13.6. (6 signal (6CAr) was not found due to overlapping peaks). Anal.
Calcd for C66H56N6: C62H48N6: C, 84.9; H, 5.5; N, 9.6; Found: C, 84.9; H, 5.5; N, 9.5.
Conflicts of interest
There are no conflicts to declare.
Acknowledgments
This study was supported by the Russian Science Foundation, Grant no. 18-13-00409 (synthetic
part, design and synthesis of compounds) and the Scientific Council of the President of the
Russian Federation, Grant no. МК-1460.2018.3 (analytical part, structure determination of
synthesized compounds).
Appendix A. Supplementary data
Supplementary data to this article can be found online at
X-ray crystallographic data
Deposition numbers CCDC 1917414 (for compound 5d) and CCDC 1917416 (for compound 6e)
contain the crystallographic data for these structures. These data can be obtained free of charge
from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
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Highlights
•
•
•
Modifications of 5,12-dihydroindolo[3,2-a]carbazole compounds were investigated
Methods for double formylation and acetylation of these heteroacenes were elaborated
Prepared diformyl and diacetyl derivatives were used to construct π-extended molecules