Russian Journal of General Chemistry, Vol. 75, No. 3, 2005, pp. 379 380. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005,
pp. 415 416.
Original Russian Text Copyright
2005 by Ismagilov, Moskva, Shamsutdinova.
Synthesis and Properties
of Phosphorylated 4-Methylpyrocatechol Derivatives
R. K. Ismagilov, V. V. Moskva, and L. M. Shamsutdinova
Kazan State Technological University, Kazan, Tatarstan, Russia
Mendeleev Russian University of Chemical Engineering, Moscow, Russia
Received July 9, 2003
Abstract Procedures for preparing -phosphorylated 4-methylpyrocatechols were developed. Diphenyl-
(3,4-dimethoxybenzyl)phosphine oxide yields diphenyl(3,4-dihydroxybenzyl)phosphine oxide under the action
of hydrobromic acid.
Alkylphenols form an important class of modern
antioxidants and biologically active compounds [1 3].
Proceeding with studies in the field of phosphorylated
phenol derivatives [4 6], we examined dimethyl
ethers of -phosphorylated 4-methylpyrocatechols.
Compounds of this type were prepared following the
scheme of the Arbuzov reaction by treating 3,4-di-
methoxybenzyl chloride with P(III) acid esters.
EXPERIMENTAL
The IR spectra of suspensions of the compounds
in mineral oil were recorded on a Specord M-80 spec-
trometer. The H and 31P NMR spectra were taken on
1
Tesla BS-567A (100 MHz) and Bruker WP-80 (32.4
MHz) spectrometers, respectively, against TMS (1H)
and 85% H3PO4 (31P).
3,4-Dimethoxybenzyl chloride was prepared accord-
ing to [8].
OCH3
Compounds I IV (general procedure). A mixture
of 0.02 mol of ethyl ester of P(III) phosphorus acid
and 0.02 mol of 3,4-dimethoxybenzyl chloride was
heated with stirring for 1.5 3 h until the evolution of
ethyl chloride was complete. Compounds I III were
isolated by vacuum distillation, and compound IV
crystallizes in the course of the reaction.
R1R2POEt + ClCH2
OCH3
OCH3
R1R2P(O)CH2
+ EtCl
OCH3
I IV
Diethyl 3,4-dimethoxybenzylphosphonate I.
Yield 43%, bp 153 156 C (0.1 mm), n2D0 1.5140, d420
R1 = R2 = EtO (I), Et (III), Ph (IV); R1 = EtO, R2 = Et (II).
1
1.1707. IR spectrum, , cm : 1600 (C6H3), 1270
(P=O), 1070, 1050 (POC). 1H NMR spectrum (CCl4 +
3
The reaction proceeds at 90 160 C; the tempera-
ture of the reaction onset decreases in going from tri-
ethyl phosphite to diethyl ethylphosphonite and then
to ethyl diethyl- and ethyl diphenylphosphinites. The
compounds prepared are colorless liquids (I, II) or
crystalline compounds (III, IV) readily soluble in
organic solvents. Compound III is soluble in water.
CDCl3), , ppm: 1.25 t (6H, CH3-ethyl, JHH 7 Hz),
2
3.15 d (2H, CH2P, JPH 23 Hz), 3.9 s (6H, CH3O),
3
4.0 q (4H, CH2OP, JHH 7 Hz), 6.9 d (3H, C6H3, 4JHH
2 Hz). 31P NMR spectrum: P 26.7 ppm. Found P, %:
10.25, 10.10. C13H21O5P. Calculated P, %: 10.74.
Ethyl ethyl(3,4-dimethoxybenzyl)phosphinate
II. Yield 51%, bp 157 158 C (0.1 mm), n2D0 1.5270,
d240 1.1730. IR spectrum, , cm : 1590 (C6H3), 1260
1
With the aim of preparing phosphorylated pyro-
catechols, compounds I, III, and IV were treated with
hydrobromic acid in acetic acid [7]. Only in IV the
hydrolysis of the ether bonds yielded the desired prod-
uct, diphenyl(3,4-dihydroxybenzyl)phosphine oxide V.
In all the other cases, we obtained intractable tars.
(P=O), 1030 (POC). Found P, %: 10.53, 10.90.
C13H21O4P. Calculated P, %: 11.38.
Diethyl 3,4-dimethoxybenzylphosphine oxide
III. Yield 57%, bp 178 179 C (0.1 mm), n2D0 1.5469,
1
mp 59 60 C (heptane). IR spectrum, , cm : 1600
(C6H3), 1250 (P=O). 31P NMR spectrum: P 45.6 ppm.
1070-3632/05/7503-0379 2005 Pleiades Publishing, Inc.
Ismagilov
