Russian Journal of General Chemistry, Vol. 72, No. 11, 2002, p. 1828. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 11, 2002, p. 1933.
Original Russian Text Copyright
2002 by Brovarets, Golovchenko, Drach.
LETTERS
TO THE EDITOR
A Convenient Route to Phosphonium
Derivatives of Coumarin and Its Imino Analog
V. S. Brovarets, A. V. Golovchenko, and B. S. Drach
Institute of Bioorganic and Petroleum Chemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
Received March 1, 2002
We found that salicylaldehyde readily reacts with
tertiary phosphonium salts I containing active me-
thylene group to form, apparently, intermediates II
which at elevated temperature undergo intramolecular
cyclization as shown in the scheme.
rate III. To a solution of 0.001 mol of phosphonium
salt Ia in 10 ml of ethanol, we added 0.0011 mol of
salicylaldehyde and 0.1 ml of piperidine. The result-
ing mixture was refluxed for 7 h and cooled, and 2 ml
of saturated aqueous solution of sodium perchlorate
was added. The precipitate was filtered off, and com-
pound III was purified by crystallization from ethanol,
O
P
+Cl
+Cl
1
P
yield 83%, mp 280 282 C. IR spectrum, , cm :
H
+
1
HN
1705 (C=O). H NMR spectrum, , ppm: 7.48 7.95 m
X
3
X
OH
(19H, 3C6H5, C6H4), 8.40 d (1H, CH, JHP 16.0 Hz).
OH
Found, %: Cl 6.85; P 6.08. C27H20O6P. Calculated, %:
Cl 6.99; P 6.11. This compound was also prepared in
89% yield by refluxing phosphonium salt IV in
dioxane in the presence of hydrochloric acid.
Ia, Ib
IIa, IIb
1) ; 2) NaClO4
EtOH
X = COOEt
1)
;
2) NaClO4
X = CN
(2-Iminocoumarin-3-yl)triphenylphosphonium
perchlorate IV was prepared similarly to III from
phosphonium salt Ib; yield 78%, mp 265 268 C after
+ClO4
P
+ClO4
P
H2O, HCl
1
recrystallization from methanol. IR spectrum, , cm :
O
NH
O
O
1600 (C=NH), 3050 3100 (NHass). Found, %: Cl 6.99;
N 2.65; P 6.10. C27H21ClNO5P. Calculated, %: Cl
7.01; N 2.77; P 6.12.
III
IV
1) NaOH;
2) HCl
COOH
o-Coumaric acid V. A suspension of 0.001 mol of
phosphonium salt III in 10 ml of 10% aqueous solu-
tion of sodium hydroxide was boiled for 5 min, the
solution was cooled, and 10% HCl was added up to
complete neutralization. The precipitate was filtered
off, and compound V was purified by crystallization
from ethanol. Yield 75%, mp 214 C, which agrees
with the published data [3].
OH
V
P = PPh3; X = COOEt (a), CN (b).
The structure of 3-phosphonium derivatives of
coumarin and its imino analog III and IV agrees with
the IR and H NMR data. This was also confirmed
by the conversion of the resulting compounds to
o-coumaric acid V. Also, a similar method was used
previously for preparing 3-phosphoryl derivatives of
coumarin and its analogs [1, 2].
1
The IR spectra were recorded on a Specord M-80
1
spectrometer in KBr pellets. The H NMR spectrum
was taken on a VXR-300 spectrometer in DMSO-d6
solution against internal TMS.
REFERENCES
The significance of accessible phosphonium re-
agents III and IV for preparing substituted styryl-
phosphonium salts and products of their transforma-
tions will be considered further.
1. Singh, R.K. and Rogers, M.D., J. Heteroatom Chem.,
1985, vol. 22, no. 6, p. 1713.
2. Chen, C.H., Fox, J.L., and Lippert, J.L., J. Heteroatom
Chem., 1987, vol. 24, no. 4, p. 931.
(Coumarin-3-yl)triphenylphosphonium perchlo-
3. Stoermer, R., Chem. Ber., 1911, vol. 44, p. 637.
1070-3632/02/7211-1828$27.00 2002 MAIK Nauka/Interperiodica