Synthesis of diphenylacetylenes containing donor and acceptor substituents with 4′-formyl-4-methoxydiphenylacetylene as an example

Article abstract of DOI:10.1023/B:RUCB.0000030827.50273.da

A method for the synthesis of diphenylacetylenes containing donor and acceptor groups in aryl substituents was proposed. 4′-Formyl-4- methoxydiphenylacetylene was synthesized as an example.

Full text of DOI:10.1023/B:RUCB.0000030827.50273.da

474
Russian Chemical Bulletin, International Edition, Vol. 53, No. 2, pp. 474—475, February, 2004
Synthesis of diphenylacetylenes containing donor and acceptor substituents
with 4´ꢀformylꢀ4ꢀmethoxydiphenylacetylene as an example
C. H. GonzálezꢀRojasa,bꢀ, Yu. F. Oprunenko , and R. G. E. Moralesa
c
aDepartment of Chemistry, University of Chile,
Santiago, Chile.
Fax: 8 (56 2) 239 2755. Eꢀmail: chgonzal@uchile.cl
b
Department of Chemistry, Metropolitan Technological University, Santiago, Chile.
c
Department of Chemistry, Moscow State University,
Leninskie Gory, 119992 Moscow, Russian Federation.
Fax: +7 (095) 939 2677. Eꢀmail: oprunenko@nmr.chem.msu.su
A method for the synthesis of diphenylacetylenes containing donor and acceptor groups in
aryl substituents was proposed. 4´ꢀFormylꢀ4ꢀmethoxydiphenylacetylene was synthesized as an
example.
Key words: copper acetylenides, diphenylacetylenes, organocopper compounds.
Diphenylacetylenes with a donor group in one phenyl
Scheme 1
substituent and an acceptor group in the other are of
considerable practical interest because the electronic propꢀ
1
erties of these compounds in the excited state allow them
to be used for creating molecular photodiodes and devices
with nonlinear optical properties.2
,3
Some diphenylacetylenes containing donor (NH2,
NHMe, NMe , and SMe) and acceptor (CN, COMe,
2
CO Me, SO Me, and NO ) substituents were synthesized
2
2
2
by direct condensations of the corresponding phenylꢀ
4
,5
acetylenes and aryl halides.
The possibility of applying the promising optoelecꢀ
tronic properties of compounds of this class can be studꢀ
ied with 4´ꢀformylꢀ4ꢀmethoxydiphenylacetylene as a
model. This compound can be synthesized from inexpenꢀ
sive and accessible reagents, which makes it most promꢀ
ising for industrial use. However, we failed to obtain
this compound in a satisfactory yield according to the
published method. For this reason, we applied the
Castro—Sladkov reaction,6,7 which consists of the introꢀ
duction of an aryl substituent into an arylacetylene molꢀ
ecule via copper acetylenide.
Results and Discussion
The synthesis of the target compound is shown in
Scheme 1. Condensation of pꢀiodoanisole (1) containing
a donor methoxy group with trimethylsilylacetylene (2) in
Et N in the presence of CuI and PdCl (PPh ) affords the
3
2
3 2
known pꢀmethoxyphenyl(trimethylsilyl)acetylene (3).
Hydrolytic elimination of the trimethylsilyl group in an
alkaline medium gives pꢀmethoxyphenylacetylene (4),
which is easily converted into copper acetylenide 5 in
high yield. The latter reacts with pꢀbromobenzaldehyde (6)
in pyridine to give the target 4´ꢀformylꢀ4ꢀmethoxyꢀ
diphenylacetylene (7).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 452—454, February, 2004.
066ꢀ5285/04/5302ꢀ0474 © 2004 Plenum Publishing Corporation
1

Diarylacetylenes
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 2, February, 2004
475
The above sequence of reactions opens a route to
diarylacetylenes containing a donor group in one aryl ring
and an acceptor group in the other.
4ꢀmethoxyphenylacetylene 4 (1.52 g, 11.50 mmol) in 50 mL of
ethanol that had preliminarily been stirred for 1 h. The reaction
mixture was stirred at ∼ 20 °C for 10 h. The greenish yellow
precipitate that formed was filtered off and successively washed
with water, ethanol, and diethyl ether. The bright yellow prodꢀ
uct was dried in a desiccator at 20 °C (1 Torr) for 4 h to give
copper 4ꢀmethoxyphenylacetylenide (5) (1.94 g, 86%). IR,
Experimental
–
1
All reactions were carried out under nitrogen. Commerꢀ
cial reagents (pꢀiodoanisole and dichlorobis(triphenylphosꢀ
phine)palladium(II) (Aldrich), CuI (Merck), and ammonia
ν/cm : 2960, 2918 (OCH3); 1600, 1494 (benzene ring); 1248
–
1
(Carom—O); 1029 (OCH3). Far IR, ν/cm : 315 (C≡C—Cu).
+
+
MS: [M] calc = 194.69, [M] exp = 194.
(
Baker)) were used as purchased. Triethylamine (Riedel de
4´ꢀFormylꢀ4ꢀmethoxydiphenylacetylene (7). Copper 4ꢀmethꢀ
oxyphenylacetylenide (5) (110 mg, 0.56 mmol) was added in a
flow of nitrogen to a stirred solution of pꢀbromobenzaldehyde (6)
(172 mg, 0.93 mmol) in dry pyridine (80 mL). The reaction
mixture was stirred for 24 h at 115 °C, turning rose amber, and
cooled. The pyridine was removed as an azeotropic mixture with
benzene and ethanol. Chromatography of the oily product in
light petroleum—ethyl acetate (7 : 1) gave 4´ꢀformylꢀ4ꢀmethoxyꢀ
diphenylacetylene (7) (22 mg, 16%) as pale yellow needles,
Rf 0.42; m.p. 133 °C. IR, ν/cm– : 2929, 2853 (OCH3); 2214
(C≡C); 1692 (C=O); 1599, 1505, 1461 (benzene ring); 1252
Haën) was distilled over CaCl and kept in an inert atmosphere.
2
Raman spectra were recorded on a PerkinꢀElmer 200 FTꢀIR
instrument. Far IR spectra were recorded on a Bruker FTꢀIR
spectrometer (polyethylene pellets). IR spectra were recorded in
the liquid phase (NaCl cuvettes). H and C NMR spectra were
recorded on a Bruker AMXꢀ300 spectrometer (300 MHz) with
1
13
(
CD ) CO as the internal standard. Signals in the NMR spectra
3 2
were not assigned by special techniques. UV spectra were reꢀ
corded on a PerkinꢀElmer Lambda 11 spectrometer in 10ꢀmm
quartz cells in EtOH. Thinꢀlayer chromatography (TLC) was
performed on silica gel plates (250 µm). Mass spectra were reꢀ
corded on a TRIO 1000 Fisons instrument (EI, 70 eV). All the
compounds obtained were described earlier.
1
1
(Carom—O) and 1026 (OCH3). H NMR, δ: 10.10 (s, 1 H,
—CHO); 8.10 (d, 2 H, H(3´), H(5´)); 7.90 (d, 2 H, H(2´),
H(6´)); 7.60 (d, 2 H, H(2), H(6)); 7.10 (d, 2 H, H(3), H(5));
13
4
ꢀMethoxyphenyl(trimethylsilyl)acetylene (3). A mixture of
4.00 (s, 3 H, MeO). C NMR, δ: 192.08 (C=O); 161.68, 136.69,
134.82, 134.15, 132.64, 130.72, 115.31, 114.35 (Carom); 89.97,
73.51 (C≡C); 55.82 (MeO). UV, λmax = 321 nm (logε = 4.53).
CuI (362 mg, 1.89 mmol) and PdCl (PPh ) (434 mg) was added
to a solution of pꢀiodoanisole 1 (6.03 g, 26.92 mmol) in dry Et N
(
2
3 2
3
+
+
60 mL) in a Schlenk vessel. The solution was stirred for 1 h
MS: [M] calc = 236.26, [M] exp = 236.
while purified N was passed through. Trimethylsilylacetylene (2)
2
This work was financially supported by the
FONDECYT foundation (Santiago, Chile) and the Postꢀ
Graduate Department of the Chile University (Grant Nos.
PG052 and PG055). One of us (C. G.) is grateful to the
Metropolitan Technological University for providing time
and research facilities.
(
3.51 g, 35.73 mmol) was added, and the reaction mixture was
stirred for 24 h. The precipitate was filtered off and the solꢀ
vent was removed in vacuo. Chromatography of the oily redꢀ
brown residue in hexane—toluene (2 : 1) gave 4ꢀmethoxyꢀ
phenyl(trimethylsilyl)acetylene (3) (5.10 g, 72%) as an oil,
–
1
R 0.60. IR, ν/cm : 2955, 2912, 2879 (OCH ); 2154 (C≡C);
f
3
1
606, 1508, 1463 (benzene ring); 1250 (Carom—O); 1031 (OCH3)
1
and 731 (≡C—Si). H NMR, δ: 7.30 (d, 2 H, H(2), H(6)); 6.80
References
(
d, 2 H, H(3), H(5)); 3.70 (s, 3 H, MeO); 0.26 (s, 9 H, Me Si).
C NMR, δ: 160.17 (C(4)); 134.17 (C(2), C(6)); 116.06 (C(1));
3
1
3
1
. C. H. GonzálezꢀRojas, Ph.D. Thesis, University of Chile,
1
14.89 (C(3), C(5)); 107.59 (Ar—C≡); 89.75 (≡C—Si); 55.66
Santiago, 1999.
(
MeO); 5.05 (Me Si). UV, λ = 259 nm (logε = 4.48).
3
max
2. P. Prasad and J. Wiliams, Introduction to Nonlinear Optical
Effects in Molecules and Polymers, Wiley Interscience, New
York, 1991.
4
ꢀMethoxyphenylacetylene (4). Compound 3 (5.1 g, 25
mmol) was treated with 2 M KOH (40 mL) in MeOH (100 mL).
The solution was filtered, the filtrate was diluted with water, and
the product was extracted with ether (3×200 mL). The extract
was dried with anhydrous Na SO and the ether was removed in
3
. D. W. Bruce and D. O´Hare, Inorganic Materials, J. Wiley
and Sons, 1992.
4. A. E. Stiegman, E. Graham, K. J. Perry, L. R. Khundkar,
L. T. Cheng, and J. W. Perry, J. Am. Chem. Soc., 1991,
2
4
vacuo. Chromatography of the oily orangeꢀred residue in hexꢀ
ane—toluene (2 : 1) gave compound 4 (3.17 g, 96%) as a yellow
1
13, 7658.
–
1
oil, R 0.54. IR, ν/cm : 3288 (≡C—H); 2955, 2912, 2879
f
5. E. Graham, V. M. Miskowski, J. W. Perry, D. Coulter, A. E.
Stiegman, W. P. Schaeffer, and R. E. Marsh, J. Am. Chem.
Soc., 1989, 111, 8771.
(
(
OCH ); 2106 (C≡C); 1606, 1507, 1464 (benzene ring), 1250
3
1
Carom—O) and 1031 (O—CH ). H NMR, δ: 7.30 (d, 2 H,
3
H(2), H(6)); 6.80 (d, 2 H, H(3), H(5)); 3.36 (s, 1 H, ≡C—H);
.74 (s, 3 H, MeO). 13C NMR, δ: 160.96 (C(4)); 133.39 (C(2),
C(6)); 115.19 (C(1)); 114.88 (C(3), C(5)); 84.25 (Ar—C≡); 77.34
6
. R. D. Stephens and C. E. Castro, J. Org. Chem., 1963, 28,
163; ibid., 1963, 28, 3313.
3
2
7
. A. M. Sladkov, L. Yu. Ukhin, and V. V. Korshak, Izv. Akad.
Nauk SSSR, Ser. Khim., 1963, 2213 [Bull. Acad. Sci. USSR,
Div. Chem. Sci., 1963, 12 (Engl. Transl.)]; A. M. Sladkov and
L. Yu. Ukhin, Usp. Khim., 1968 [Russ. Chem. Rev., 1968, 37,
748 (Engl. Transl)].
(
≡C—H); 55.66 (MeO). UV, λmax = 250 nm (logε = 4.31).
Copper 4ꢀmethoxyphenylacetylenide (5). A solution of CuI
1.74 g, 17.57 mmol) in saturated aqueous ammonia (150 mL)
(
was stirred for 1 h in a Schlenk vessel under purified N . Then,
2
hydroxylamine hydrochloride (1.35 mg, 19.42 mmol) was added
as a reducing agent to prevent possible oxidation of Cu(I).
The resulting mixture was added under N2 to a solution of
Received May 13, 2003;
in revised form February 10, 2004