Synthesis of unsaturated aldehydes from m-phenoxybenzaldehyde

Full text of DOI:10.1023/A:1012480708198

Russian Journal of Organic Chemistry, Vol. 37, No. 5, 2001, pp. 748 749. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 5, 2001,
pp. 783 784.
Original Russian Text Copyright
2001 by Popov, Korchagina, Stepochkina.
SHORT
COMMUNICATIONS
Synthesis of Unsaturated Aldehydes
from m-Phenoxybenzaldehyde
Yu. V. Popov, T. K. Korchagina, and D. G. Stepochkina
Volgograd State Technical University, pr. Lenina 28, Volgograd, 400131 Russia
Received July 10, 2000
Aldehydes constitute an important class of carbonyl
The purity of the products was checked by gas
liquid chromatography. Their structure was confirmed
by IR spectroscopy and elemental analysis. The IR
spectra of IVa IVd contained characteristic absorp-
compounds which are widely used in synthetic
organic chemistry due to their high reactivity. The
presence in a single molecule of a carbonyl group,
a double C C bond, and a diphenyl ether moiety
gives rise to specific properties of such compounds,
especially when these groups are located close to each
other [1].
1
tion bands at 1620 1640 (C C) and 1670 1685 cm
(C O), whereas hydroxy group absorption at 3620
1
3650 cm was lacking. Numerous bands in the region
1
1440 1490 cm indicated the presence of more than
one benzene ring.
We examined aldol condensation of m-phenoxy-
benzaldehyde (I) with various aliphatic aldehydes
IIa IId and obtained unsaturated aldehydes IIIa IIId
having a diphenyl ether moiety (Scheme 1). The reac-
tions were carried out in methanol at a molar ratio
I:II of 1:3; the reaction time was 8 h, and a 10% so-
lution of potassium hydroxide in methanol was used
as catalyst. In order to prevent self-condensation of
the aliphatic aldehyde, it was slowly added to a solu-
tion of m-phenoxybenzaldehyde and potassium
hydroxide in methanol, cooled to 5 7 C, and pH of
the medium was continuously monitored. We thus
succeeded in obtaining a number of new unsaturated
aldehydes IVa IVd in 53 74% yield. The products
were isolated by repeated vacuum distillation.
2-Ethyl-3-m-phenoxyphenyl-2-propenal (IVb).
A solution of 2.5 g (0.045 mol) of potassium hy-
droxide in methanol was added dropwise to a solution
of 17.25 g (0.087 mol) of m-phenoxybenzaldehyde
in 8.71 g (0.272 mol) of methanol, cooled to 5 7 C.
A solution of 18.88 g (0.262 mol) of freshly distilled
butyraldehyde in 8.71 g (0.272 mol) of methanol was
added dropwise over a period of 1 h, maintaining the
temperature below 10 C. The mixture was stirred for
8 h, neutralized with glacial acetic acid, and extracted
with diethyl ether. The solvent was removed, and the
residue was distilled in a vacuum. Yield 16 g (73%),
bp 191 192 C (3 mm). Found, %: C 80.63; H 6.51.
C17H16O2. Calculated, %: C 80.93; H 6.35.
Scheme 1.
R = CH3 (a), CH2CH3 (b), CH2CH2CH3 (c), CH(CH3)2 (d).
1070-4280/01/3705-0748$25.00 2001 MAIK Nauka/Interperiodica

SYNTHESIS OF UNSATURATED ALDEHYDES
749
2-Methyl-3-m-phenoxyphenyl-2-propenal (IVa)
was synthesized in a similar way from 17.25 g
(0.087 mol) of aldehyde I, 17.42 g of methanol, 2.5 g
(0.045 mol) of KOH, and 15.22 g (0.262 mol) of
freshly distilled propionaldehyde. Yield 11 g (53%),
bp 195 196 C (2 mm). Found, %: C 80.90; H 6.02.
C16H14O2. Calculated, %: C 80.67; H 5.88.
2-Propyl-3-m-phenoxyphenyl-2-propenal (IVc)
was synthesized in a similar way from 17.25 g
(0.087 mol) of aldehyde I, 17.42 g (0.544 mol) of
methanol, 2.5 g (0.045 mol) of KOH, and 22.57 g
(0.262 mol) of freshly distilled pentanal. Yield 13 g
(56%), bp 205 207 C (2 mm). Found, %: C 80.43;
H 6.54. C18H18O2. Calculated, %: C 80.90; H 6.74.
(0.087 mol) from aldehyde I, 17.42 g (0.544 mol) of
methanol, 2.5 g (0.045 mol) of KOH, and 22.57 g
(0.262 mol) of freshly distilled 3-methylbutanal. Yield
16.7 g (72%), bp 203 205 C (2 mm). Found, %:
C 81.25; H 6.14. C18H18O2. Calculated, %: C 80.90;
H 6.74.
GLC analysis was performed on a Sigma-300
chromatograph using a 2-m column packed with
15% of SKTFT on Inerton N-AV, injector temperature
270 C. The IR spectra were obtained from solutions
in chloroform using a Perkin Elmer instrument.
REFERENCE
2-Isopropyl-3-m-phenoxyphenyl-2-propenal
(IVd) was synthesized in a similar way from 17.25 g
1. Patai, S. and Israeli, Y., J. Chem. Soc., 1960,
pp. 2020 2025.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 5 2001