Synthesis of new polyconjugated compounds based on 9,10- diphenylphenanthrene

Article abstract of DOI:10.1134/S1070428010080099

A procedure was developed for the synthesis of dimethyl 9,10-diphenylphenanthrene-2,7-dicarbox-ylate, and the latter was used as starting compound for the preparation of 9,10-diphenyl-2,7-bis(2-phenyl-ethenyl) phenanthrene derivatives and 2,7-bis[(E)-2-(1,3-benzoxazol-2-yl)ethenyl]-9,10- diphenylphenanthrene, which showed strong luminescence in the solid state and in solution. Spectral properties of the products were studied. Pleiades Publishing, Ltd., 2010.

Full text of DOI:10.1134/S1070428010080099

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 8, pp. 1167–1172. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © V.K. Ol’khovik, V.A. Vasilevskii, N.A. Galinovskii, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 8,
pp. 1167–1172.
Synthesis of New Polyconjugated Compounds
Based on 9,10-Diphenylphenanthrene
V. K. Ol’khovik, V. A. Vasilevskii, and N. A. Galinovskii
Institute of New Materials Chemistry, National Academy of Sciences of Belarus,
ul. F. Skoriny 36, Minsk, 220141 Belarus
e-mail: slavol@ichnm.basnet.by
Received August 8, 2009
Abstract—A procedure was developed for the synthesis of dimethyl 9,10-diphenylphenanthrene-2,7-dicarbox-
ylate, and the latter was used as starting compound for the preparation of 9,10-diphenyl-2,7-bis(2-phenyl-
ethenyl)phenanthrene derivatives and 2,7-bis[(E)-2-(1,3-benzoxazol-2-yl)ethenyl]-9,10-diphenylphenanthrene,
which showed strong luminescence in the solid state and in solution. Spectral properties of the products were
studied.
DOI: 10.1134/S1070428010080099
Fused polycyclic aromatic compounds attract strong
interest as chromophore building blocks in the syn-
thesis of electroluminescent dyes and organic semicon-
ductors [1]. Substituted phenanthrenes I having func-
tional groups in positions 2 and 7 (Scheme 1) possess
the most extended conjugation chain, and they can be
used in the synthesis of new polyvinylene and other
polyconjugated aromatic systems like II. However,
direct functionalization of phenanthrene and its homo-
logs is not always regioselective, so that this approach
is inappropriate. A promising approach to targeted
structures may be that based on palladium-catalyzed
reaction of aryl iodides with alkynes, which ensures
one-step preparation of polycyclic aromatic com-
pounds with required functionalities [2, 3].
In the present communication we report on the syn-
thesis of dimethyl 9,10-diphenylphenanthrene-2,7-di-
carboxylate (VI) and a series of luminescent dyes
based thereon. The presence of methoxycarbonyl
groups in positions 2 and 7 of molecule VI makes it
possible to readily append side chains in the opposite
directions and obtain derivatives possessing extended
π-conjugation systems, which are potential electroac-
tive materials.
Mandal et al. [2] previously reported on the forma-
tion of 9,10-diphenylphenanthrene-2,7-dicarboxylates
in a very poor yield (no less than 9%) in the reactions
of 2,2′-diiodobiphenyl-4,4′-dicarboxylic acid esters
with diphenylacetylene in the presence of palladium
acetate [2]. An alternative version of the synthesis of
substituted 9,10-diphenylphenanthrenes from 2-iodobi-
phenyls was proposed in [3]. However, coupling with
diphenylacetylene was studied only for biphenyls
having only one electron-donating substituent in the
iodine-free aromatic ring. We tried to apply analogous
approach to the synthesis of dimethyl 9,10-diphenyl-
phenanthrene-2,7-dicarboxylate (VI). As starting com-
pound we used the corresponding iodo derivative, di-
methyl 2-iodobiphenyl-4,4′-dicarboxylate (V) which
was synthesized according to Scheme 2. Nitration of
dimethyl biphenyl-4,4′-dicarboxylate (III), followed
by hydrogenation of the 2-nitro derivative over Pd/C
gave amine IV [4] which was subjected to diazotiza-
tion and treatment with sodium iodide. Iodide V was
Scheme 1.
MeO
O
OMe
O
R
R
I
II
1167

OL’KHOVIK et al.
1168
Scheme 2.
(1) HNO3, H2SO4
(2) H2, Pd/C
MeO
O
O
MeO
O
O
OMe
OMe
H2N
III
IV
Ph
Ph
(1) HCl, NaNO2
(2) NaI
Pd(OAc)2, LiCl
MeO
O
O
MeO
O
O
NaOAc, DMF
OMe
OMe
I
Ph
Ph
V
VI
thus synthesized in 60% yield. Substituted phenan-
threne VI was obtained in 42% yield by heating a solu-
tion of iodo diester V, diphenylacetylene, and palladi-
um(II) acetate in anhydrous N,N-dimethylformamide at
100°C over a period of 140 h.
As noted above, the presence of ester groups in
positions 2 and 7 of molecule VI ensures its facile
functionalization to obtain rigid linear polyconjugated
systems. p-Phenylenevinylene analogs conjugated with
aromatic or heterocyclic fragments in the main or side
chain attract much attention as promising luminescent
materials for the preparation of organic light-emitting
diodes [5–7]. Taking the above into account, we made
an attempt to obtain on the basis of dimethyl 9,10-di-
phenylphenanthrene-2,7-dicarboxylate (VI) a series of
new short-chain poly-p-phenylenevinylene analogs pos-
sessing both electron-withdrawing and electron-donat-
ing groups in the main conjugation chain (Scheme 3).
The reduction of diester VI with lithium tetrahy-
dridoaluminate in tetrahydrofuran gave diol VII which
was oxidized to the corresponding dialdehyde VIII
with pyridinium chlorochromate in dioxane (yield
77%). Compound VIII was then brought into Knoeve-
nagel and Wittig condensations to obtain poly-π-con-
jugated systems containing electron-withdrawing and
electron-donating fragments. The condensation of dial-
dehyde VIII with 2-methylbenzoxazole in the presence
of sodium methoxide afforded compound X. Dialde-
hyde VIII also reacted with benzyl(triphenyl)phospho-
nium chloride according to Wittig to produce sym-
metrically substituted phenanthrene IX in good yield
(Scheme 3). These reactions were characterized by
Scheme 3.
O
HO
LiAlH4, THF
[O]
VI
OH
O
Ph
Ph
Ph
Ph
VII
VIII
Ph
PhCH2PPh3 Cl
t-BuOK, THF
Ph
Ph
Ph
IX
N
O
N
Me
O
N
O
MeONa, DMSO
Ph
Ph
X
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

SYNTHESIS OF NEW POLYCONJUGATED COMPOUNDS
1169
Scheme 4.
Cl
Cl– Ph3P
SOCl2, toluene
Ph3P, DMF
Cl
VII
PPh3 Cl–
Ph
Ph
R
Ph
Ph
R
XI
XII
4-RC6H4CHO (XIII, XIV)
t-BuOK, THF
Ph
Ph
XV, XVI
XIII, XV, R = CN; XIV, XVI, R = NPh2.
high stereoselectivity, and the major products were the
six protons in the phenanthrene core with the expected
multiplicities. The steric configuration of compounds
IX, X, XV, and XVI was determined on the basis of
corresponding trans,trans isomers.
This scheme of synthesis ensures preparation of
a relatively limited series of ethenyl derivatives, de-
pending on the accessibility of benzyl(triphenyl)phos-
phonium salts, which is determined in turn by the
nature of substituents in the benzene ring. In order to
obtain difficultly accessible compounds, especially
those containing several triarylamine fragments in the
conjugation chain, we followed an alternative trans-
formation sequence: the corresponding ylide was gen-
erated from bis-triphenylphosphonium salt XII derived
from phenanthrene XI, and subsequent coupling with
monosubstituted benzaldehydes XIII and XV gave
target products XIV and XVI, respectively (Scheme 4).
Dichloride XI was synthesized by treatment of diol
VII with thionyl chloride, and compound XI reacted
with triphenylphosphine, yielding bis-phosphonium
salt XII. Compounds XV and XVI were formed exclu-
sively as trans,trans isomers.
1
the H NMR data. Signals from protons at the exo-
cyclic double bonds in compound IX resonated in the
1H NMR spectrum as two doublets at δ 7.45 ppm with
a vicinal coupling constant of 16.5 Hz which is typical
of their trans orientation.
All compounds IX, X, XV, and XVI, both in the
crystalline state and in solution, showed strong lumi-
nescence in the blue region of the spectrum. As follows
from the data given in table, additional electron-with-
drawing substituents in the main conjugation chain
of compounds X and XV do not affect their spectral
parameters to an appreciable extent, and these com-
pounds differ only slightly from 2,7-bis(phenylethenyl)
derivative IX. By contrast, the presence of an electron-
donor fragment in molecule XVI is responsible for
a strong red shift of fluorescence maximum of this
compound, while extension of the conjugation induces
more than threefold increase in its molar absorption
coefficient, as well as strong increase in the photolumi-
nescence quantum yield as compared to compound IX.
The structure of the isolated compounds was con-
firmed by 1H NMR, IR, and mass spectra. The 1H NMR
spectra of VI–XI and XV–XVI contained signals from
Electronic absorption spectra and photoluminescence of phenanthrene derivatives VI, IX, X, XV, and XVI
Compound no.
Absorption, λmax, nm
ε, l mol–1 cm–1
Fluorescence, λmax, nm
VI
IX
X
XV
XVI
289.5
36000
420
305, 366.5.0
306.5, 385.0
298.5, 382.0
298.5, 409.5
46000, 59800
42500, 87000
41500, 74400
163900, 195200
428, 447a
442, 481a
449, 479a
480, 485a
a
In the solid state.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

OL’KHOVIK et al.
acetate in 50 ml of DMF was stirred for 72 h at 95–
1170
EXPERIMENTAL
105°C. The mixture was cooled to room temperature
and diluted with water (100 ml), and the precipitate
was filtered off, washed with hexane, and recrys-
tallized from o-xylene. Yield 0.61 g (42%), mp 309–
310°C. IR spectrum, ν, cm–1: 3440, 3100, 3050, 2970,
1730, 1570, 1440, 1390, 1340, 1300, 1260, 1210,
The melting points were determined on a Kofler
melting point apparatus equipped with a Hanna HI
1
93530 electronic thermometer. The H NMR spectra
were recorded on a Bruker Biospin Avance 500 spec-
trometer (500 MHz). The IR spectra were measured in
the range from 400 to 4000 cm–1 on a Specord M-80
instrument from samples prepared as KBr pellets. The
electronic absorption and fluorescence spectra were
recorded from solutions in DMF or microcrystalline
samples on a Solar CM2203 spectrofluorimeter (exci-
tation wavelength 365 nm). The mass spectra (atmos-
pheric pressure chemical ionization) were obtained on
an Accela-LCQ Fleet mass chromatograph. The sol-
vents and reagents used were purified and dehydrated
by standard methods to a pure or analytical grade. The
progress of reactions was monitored by TLC on alumi-
num plates coated with silica gel 60 F254 (Merck).
Dimethyl 2-iodobiphenyl-4,4′-dicarboxylate (V).
A solution of 1.42 g (5 mmol) of dimethyl 2-amino-
biphenyl-4,4′-dicarboxylate (IV) [4] in 5 ml of 15%
hydrochloric acid was cooled to 0–4°C, and a solution
of 0.4 g (5.8 mol) of sodium nitrite in 3 ml of water
was added dropwise under vigorous stirring. The mix-
ture was stirred for 10 min at 0–4°C, a solution of
0.9 g (6 mmol) of sodium iodide in 3 ml of water was
added, and the mixture was heated to 60°C and kept
for 10 min at that temperature. The mixture was cooled
to room temperature, diluted with 50 ml of water, and
extracted with ethyl acetate (3×75 ml). The combined
extracts were washed in succession with a 10% solu-
tion of NaHSO3, water, a saturated solution of NaHCO3,
and water again and dried over anhydrous Na2SO4. The
solvent was distilled off under reduced pressure, and
the crude product was purified by column chromatog-
raphy on silica gel using toluene as eluent, followed by
recrystallization from ethanol. Yield 1.2 g (60%),
mp 112–113°C. IR spectrum, ν, cm–1: 3450, 2970,
1730, 1440, 1290, 1250, 1140, 970, 850, 770, 720.
1H NMR spectrum (CDCl3), δ, ppm: 3.89 s (6H,
OCH3), 7.29 d (1H, 6-H, J = 8 Hz), 7.36 d (2H, 6′-H,
2′-H, J = 8.5 Hz), 7.99 d.d (1H, 5-H, J = 8, 1.5 Hz),
8.06 d (2H, 5′-H, 3′-H, J = 8.5 Hz), 8.56 d (1H, 3-H,
J = 1.5 Hz). Found, %: C 48.65; H 3.24; I 32.10.
C16H13IO4. Calculated, %: C 48.51; H 3.31; I 32.03.
1
1130, 1020, 970, 830, 770, 710. H NMR spectrum
(CDCl3), δ, ppm: 3.81 s (6H, OCH3), 7.20–7.40 m
(10H, Harom), 8.09 d (2H, 1-H, 8-H, J = 1.5 Hz),
8.22 d.d (2H, 3-H, 6-H, J = 9, 1.5 Hz), 9.13 d (2H,
4-H, 5-H, J = 9 Hz). Found, %: C 80.55; H 5.07.
C30H22O4. Calculated, %: C 80.70; H 4.97.
(9,10-Diphenylphenanthrene-2,7-diyl)dimetha-
nol (VII). A solution of 2.3 g (5.1 mmol) of diester VI
in 10 ml of tetrahydrofuran was added to a suspension
of 0.2 g (5.1 mmol) of lithium tetrahydridoaluminate in
5 ml of THF. The mixture was heated for 4 h under
reflux, cooled to room temperature, and treated with
2 ml of a 10% solution of sodium hydroxide. The
precipitate was filtered off and washed with 50 ml of
THF, the filtrate was evaporated under reduced pres-
sure, and the residue was recrystallized from isopropyl
alcohol. Yield 1.7 g (85%), mp 235–235.5°C. IR spec-
trum, ν, cm–1: 3300, 3070, 2860, 1490, 1450, 1410,
1
1300, 1180, 1070, 1050, 1010, 805, 700. H NMR
spectrum (CDCl3), δ, ppm: 4.57 d (4H, CH2OH, J =
5.5 Hz), 5.18 t (2H, OH, J = 5.5 Hz), 7.1– 7.3 m (10H,
Harom), 7.39 d (2H, 1-H, 8-H, J = 1.5 Hz), 7.65 d.d (2H,
3-H, 6-H, J = 9, 1.5 Hz), 8.83 d (2H, 4-H, 5-H, J =
9 Hz). Found, %: C 86.28; H 5.75. C28H22O2. Calculat-
ed, %: C 86.13; H 5.68.
9,10-Diphenylphenanthrene-2,7-dicarbaldehyde
(VIII). Diol VII, 0.39 g (1 mmol), was dissolved in
5 ml of dioxane, 0.63 g of pyridinium chlorochromate
in 10 ml of dioxane was added under vigorous stirring,
and the mixture was stirred for 3 h at room tempera-
ture. The mixture was then diluted with 5 ml of di-
oxane, the solution was separated by decanting and
passed through a layer of silica gel, the precipitate
(a dark brown material) was dissolved in a 10% solu-
tion of sodium hydroxide, and the alkaline solution
was extracted with toluene. The extract was combined
with the organic phase, washed with water until neutral
reaction, and dried over MgSO4. The solvent was
distilled off under reduced pressure, and the residue
was recrystallized from ethanol. Yield 0.3 g (77%),
mp 265°C. IR spectrum, ν, cm–1: 3070, 2850, 1690,
1610, 1580, 1450, 1435, 1380, 1300, 1230, 1200,
Dimethyl 9,10-diphenylphenanthrene-2,7-dicar-
boxylate (VI). A mixture of 1.3 g (3.2 mmol) of iodo-
biphenyl V, 0.138 g (3.2 mmol) of LiCl, 0.65 g
(3.5 mmol) of diphenylacetylene, 0.04 g (5 mol %) of
palladium(II) acetate, and 0.5 g (6.4 mmol) of sodium
1
1150, 1090, 1040, 920, 830, 710. H NMR spectrum
(CDCl3), δ, ppm: 7.10–7.30 m (10H, Harom), 8.03 d
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

SYNTHESIS OF NEW POLYCONJUGATED COMPOUNDS
1171
(2H, 1-H, 8-H, J = 1.5 Hz), 8.14 d.d (2H, 3-H, 6-H, J =
9, 1.5 Hz), 8.90 d (2H, 4-H, 5-H, J = 9 Hz), 9.96 s (2H,
CHO). Found, %: C 87.22; H 4.62. C28H18O2. Calcu-
lated, %: C 87.02; H 4.69.
boiling point and kept boiling for 10 min. After cool-
ing to room temperature, the mixture was poured into
50 ml of water, and the organic phase was separated,
washed in succession with water, a saturated solution
of NaHCO3, and water again, and dried over anhy-
drous Na2SO4. The solvent was removed under
reduced pressure, and the residue was purified by
column chromatography on silica gel using toluene as
eluent. The product was additionally recrystallized
from isopropyl alcohol. Yield 1.7 g (95%), mp 65–
67°C. IR spectrum, ν, cm–1: 3070, 3040, 2930, 1610,
1490, 1450, 1410, 1260, 1090, 1040, 1010, 810, 710.
1H NMR spectrum (CDCl3), δ, ppm: 4.58 s (4H,
CH2Cl), 7.10–7.30 m (10H, Harom), 7.45 d (2H, 1-H,
8-H, J = 1.5 Hz), 7.67 d.d (2H, 3-H, 6-H, J = 8.5,
1.5 Hz), 8.73 d (2H, 4-H, 5-H, J = 8.5 Hz). Found, %:
C 78.47; H 4.79; Cl 16.50. C28H20Cl2. Calculated, %:
C 78.69; H 4.72; Cl 16.59.
(9,10-Diphenylphenanthrene-2,7-diyldimethyl-
ene)bis(triphenylphosphonium) dichloride (XII).
Compound XI, 1.9 g (4.5 mmol), and triphenylphos-
phine, 2.33 g (12 mmol), were dissolved under argon
in 50 ml of DMF. The mixture was heated for 5 h
under reflux, 2/3 of the solvent was removed under
reduced pressure, and 70 ml of toluene was added to
the residue. The precipitate was filtered off and dried
under reduced pressure. Yield 2.15 g (51%), decom-
position point 250°C. IR spectrum, ν, cm–1: 3450,
2950, 2850, 1440, 1120, 750, 720, 680, 500.
9,10-Diphenyl-2,7-bis[(E)-2-phenylethenyl]-
phenanthrene (IX). Potassium tert-butoxide, 0.07 g
(0.6 mmol), was added under nitrogen to 0.2 g
(0.5 mmol) of benzyl(triphenyl)phosphonium chloride,
a solution of 0.1 g (0.25 mmol) of dialdehyde VIII in
5 ml of THF was added dropwise over a period of
5 min, and the mixture was stirred for 4 h at 40°C. The
mixture was then treated with water (50 ml) and ex-
tracted with chloroform (3×75 ml). The extracts were
washed with water, a saturated solution of sodium
chloride, and water again, dried over Na2SO4, and
evaporated under reduced pressure. The residue was
purified by column chromatography on silica gel using
toluene as eluent. Yield 0.1 g (82%), mp 322–323°C.
IR spectrum, ν, cm–1: 3070, 3030, 2240, 1610, 1510,
1
1480, 1450, 1420, 1190, 970, 870, 840, 710. H NMR
spectrum (DMSO-d6), δ, ppm: 7.10–7.30 m (20H,
Harom), 7.42 d (2H, 1-H, 8-H, J = 1.5 Hz), 7.45 d (2H,
CH=CH, J = 16.5 Hz), 7.45 d (2H, CH=CH, J =
16.5 Hz), 7.87 d.d (2H, 3-H, 6-H, J = 9, 1.5 Hz),
8.69 d (2H, 4-H, 5-H, J = 9 Hz). Mass spectrum:
m/z 535 [M + 1]+.
2-{(E)-7-[(E)-2-(1,3-Benzoxazol-2-yl)ethenyl]-
9,10-diphenylphenanthren-2-ylethenyl}-1,3-benzox-
azole (X). Anhydrous dimethyl sulfoxide, 60 ml,
2-methylbenzoxazole, 0.15 g (1.1 mmol), and dialde-
hyde VIII, 0.15 g (0.4 mmol), were added in succes-
sion to a solution of sodium methoxide prepared from
0.05 g (2.1 mmol) of metallic sodium and 3 ml of
anhydrous methanol. The mixture was heated to 40°C
and stirred for 4 h at that temperature. After cooling,
the precipitate was filtered off and washed with di-
methyl sulfoxide (3×5 ml). The product was recrystal-
lized from DMSO. Yield 0.16 g (60%), mp >360°C. IR
spectrum, ν, cm–1: 3070, 3040, 1640, 1540, 1460,
1360, 1250, 1190, 1170, 1020, 970, 950, 830, 810,
4-{(E)-7-[(E)-2-(4-Cyanophenyl)ethenyl]-9,10-
diphenylphenanthren-2-ylethenyl}benzonitrile
(XV). A solution of 0.10 g (0.92 mmol) of potassium
tert-butoxide in 10 ml of THF was added under nitro-
gen to 0.44 g (0.46 mmol) of Wittig salt XII, the mix-
ture was stirred for 10 min at room temperature, a so-
lution of 0.12 g (0.92 mmol) of aldehyde XIII in 5 ml
of THF was added dropwise over a period of 5 min.
and the mixture was stirred for 4 h at 40°C, treated
with water (50 ml), and extracted with chloroform
(3×75 ml). The extracts were washed with water, a sat-
urated solution of NaCl, and water again, dried over
Na2SO4, and evaporated under reduced pressure, and
the residue was purified by column chromatography on
silica gel using toluene as eluent. Yield 0.2 g (77%),
mp >360°C. IR spectrum, ν, cm–1: 3070, 3030, 2240,
1640, 1610, 1510, 1480, 1450, 1420, 1190, 970, 870,
1
750, 710. H NMR spectrum (CF3COOD), δ, ppm:
6.60–6.80 m (10H, Harom), 6.84 d (2H, CH=CH, J =
16 Hz), 7.10–7.30 m (8H, benzoxazole), 7.52 d (2H,
1-H, 8-H, J = 1.5 Hz), 7.62 d.d (2H, 3-H, 6-H, J = 9,
1.5 Hz), 7.89 d (2H, CH=CH, J = 16 Hz), 8.48 d (2H,
4-H, 5-H, J = 9 Hz). Mass spectrum: m/z 617 [M + 1]+.
1
840, 710. H NMR spectrum (DMSO-d6), δ, ppm:
2,7-Bis(chloromethyl)-9,10-diphenylphenan-
threne (XI). Thionyl chloride, 2 ml (25 mmol), was
added to solution of 1.6 g (4.1 mmol) of diol VII in
100 ml of toluene, and the mixture was heated to the
7.10–7.30 m (10H, Harom), 7.37 d (2H, CH=CH, J =
16.5 Hz), 7.45 d (2H, CH=CH, J = 16.5 Hz), 7.45 d
(2H, 1-H, 8-H, J = 1.5 Hz), 7.76 d (4H, Harom, J =
9.5 Hz), 7.80 d (4H, Harom, J = 9.5 Hz), 8.13 d.d (2H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

OL’KHOVIK et al.
1172
3-H, 6-H, J = 8.5, 1.5 Hz), 8.99 d (2H, 4-H, 5-H, J =
8.5 Hz). Mass spectrum: m/z 584 [M]–.
CH=CH, J = 16 Hz), 7.56 d (4H, Harom, J = 9.5 Hz),
7.72 d (4H, Harom, J = 9.5 Hz), 7.97 d.d (2H, 3-H, 6-H,
J = 8.5, 1.5 Hz), 8.68 d (2H, 4-H, 5-H, J = 8.5 Hz).
Mass spectrum: m/z 869 [M + 1]+.
4-[(E)-2-{7-(E)-2-[4-(Diphenylamino)phenyl]-
ethenyl-9,10-diphenylphenanthren-2-yl}ethenyl]-
N,N-diphenylaniline (XVI). A solution of 0.10 g
(0.92 mmol) of potassium tert-butoxide in 10 ml of
THF was added under nitrogen to 0.44 g (0.46 mmol)
of Wittig salt XII, the mixture was stirred for 10 min at
room temperature, a solution of 0.25 g (0.92 mmol) of
aldehyde XIV in 5 ml of THF was added dropwise,
and the mixture was stirred for 4 h at 40°C, treated
with 50 ml of water, and extracted with chloroform
(3×75 ml). The combined extracts were washed with
water, a saturated solution of NaCl, and water again,
dried over Na2SO4, and evaporated under reduced
pressure, and the residue was purified by column
chromatography on silica gel using hexane–toluene
(1:1) as eluent. Yield 0.2 g (81%), mp 112–113°C. IR
spectrum, ν, cm–1: 3070, 3040, 1600, 1500, 1450,
1340, 1320, 1270, 1190, 1090, 1040, 970, 830, 760,
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1
710. H NMR spectrum (DMSO-d6), δ, ppm: 7.00–
7.30 m (30H, Harom), 7.31 d (2H, CH=CH, J = 16 Hz),
7.40 d (2H, 1-H, 8-H, J = 1.5 Hz), 7.45 d (2H,
7. Janietz, S., Anlauf, S., and Wedel, A., Synth. Met., 2001,
vol. 122, p. 11.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010