New data on the reaction of diethyl hydrogen phosphite with 3,5-di-tert-butyl-4-hydroxybenzaldehyde

Article abstract of DOI:10.1023/A:1013986516728

3,3′,5,5′-Tetra-tert-butylstilbene quinone and 1,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-1,2-bis-(diethoxyphosphinoyl)-ethane were isolated from a mixture of products of the reaction of equivalent amounts of diethyl hydrogen phosphite and 3,5-di-tert-butyl-4-hydroxybenzaldehyde. A scheme of chemical transformations in this reaction system was offered.

Full text of DOI:10.1023/A:1013986516728

Russian Journal of General Chemistry, Vol. 71, No. 10, 2001, pp. 1547 1549. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 10, 2001,
pp. 1634 1636.
Original Russian Text Copyright
2001 by Ismagilov, Moskva, Mosunova, Romakhin.
New Data on the Reaction of Diethyl Hydrogen Phosphite
with 3,5-Di-tert-butyl-4-hydroxybenzaldehyde
R. K. Ismagilov, V. V. Moskva, L. Yu. Mosunova, and A. S. Romakhin
Kazan State Technological University, Kazan, Tatarstan, Russia
Received March 22, 2000
Abstract 3,3 ,5,5 -Tetra-tert-butylstilbene quinone and 1,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-1,2-bis-
(diethoxyphosphinoyl)-ethane were isolated from a mixture of products of the reaction of equivalent amounts
of diethyl hydrogen phosphite and 3,5-di-tert-butyl-4-hydroxybenzaldehyde. A scheme of chemical trans-
formations in this reaction system was offered.
It was previously shown that diethyl hydrogen
phosphite reacts with 3,5-di-tert-butyl-4-hydroxy-
dimerizes to 3,3 ,5,5 -tetra-tert-butylstilbene quinone
(I). Pathway b includes intramolecular dehydration to
benzaldehyde in different ways, depending on reactant form 2,6-di-tert-butyl-4-(diethoxyphosphinoyl)me-
ratio [1, 2].
thylene-2,5-cyclohexadienone and dimerization of the
latter to 1,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-
1,2-bis(diethoxyphosphinoyl)ethane (II).
In the present work we reacted equimolar amounts
of diethyl hydrogen phosphite and 3,5-tert-butyl-4-
hydroxybenzaldehyde. The reaction was carried out
in boiling p-xylene for 6 h. The presence of the start-
ing reagents in the final reaction mixture (3,5-di-tert-
butyl-4-hydroxybenzaldehyde precipitates from the
reaction mixture just after cooling, and diethyl hydro-
The proposed scheme is supported by the obseva-
tion of a signal assignable to diethyl hydrogen phos-
phate ( 2 ppm) in the 31P NMR spectrum of the
reaction Pmixture. Dimerization of 2,6-di-tert-butyl-4-
(diethoxyphosphinoylmethylene)-2,5-cyclohexadi-
enone was carried out separately. The low yield of
gen phosphite gives a signal at
6.4 ppm in the 31P
NMR spectrum of the reaction Pmixture) is indirect product II may be explained by the fact that separate
evidence showing that the reaction is slow and
reversible.
stages of the reaction in question are only slightly
shifted to the side of the dimeric compound.
3,3 ,5,5 -Tetra-tert-butylstilbene quinone (I) and
1,2-bis(diethoxyphosphinoyl)butyl-1,2-bis(3,5-di-tert-
4-hydroxyphenyl)ethane (II) were isolated from the
reaction mixture in low yields. Basing on published
data on the properties of -substituted derivatives of
sterically hindered phenols [3, 4], phosphonate
phosphate rearrangement [5], and dimerization of
methylenequinone structures [3, 4, 6], the formation
of compounds I and II can be explained by a scheme
including a number of parallel and consecutive stages.
EXPERIMENTAL
The IR spectra were recorded on a Specord M-80
spectrometer for suspensions in Vaseline oil. The H
1
NMR spectra were obtained on a Bruker WP-80 s
pectrometer (32.38 MHz). The phosphorus chemical
shift was measured against 85% phosphoric acid. The
yields of the products (in per cent) are not presented
since the reaction is incoplete and occurs by several
pathways.
The Abramov addition of diethyl hydrogen phos-
phite to the starting aldehyde yields diethyl (3,5-di-
3,3 ,5,5 -Tetra-tert-butylstilbene quinone (I) and
1,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-1,2-bis-
(diethoxyphosphinoyl)ethane (II). A solution of
1.38 g of diethyl hydrogen phosphite and 2.34 g of
di-tert-butyl-4-hydroxybenzaldehyde in 15 ml of p-
xylene was refluxed for 6 h. After cooling of the dark
claret reaction mixture, 0.14 g of the starting aldehyde
was isolated. Most p-xylene was removed in a
vacuum at a temperature below 60 C. The residue was
tert-butyl- ,4-dihydroxybenzyl)phosphonate.
The
latter on heating may convert by two pathways.
Pathway a involves the phosphonate phosphate rear-
rangement leading to diethyl 3,5-di-tert-butyl-4-
hydroxybenzyl phosphate which cleaves diethyl
hydrogen phosphate to give 2,6-di-tert-butyl-4-me-
thylene-2,5-cyclohexadienone. The latter in its turn
1070-3632/01/7110-1547$25.00 2001 MAIK Nauka/Interperiodica

1548
ISMAGILOV et al.
t-Bu
HO
t-Bu
H
O
C
(EtO)2P(O)H
t-Bu
HO
t-Bu
CH P(O)(OEt)2
OH
a
b
H2O
t-Bu
O
t-Bu
HO
CH P(O)(OEt)2
CH2 OP(O)(OEt)2
t-Bu
t-Bu
t-Bu
O
t-Bu
O
CH2 + (EtO)2P(O)OH
CH P(O)(OEt)2
t-Bu
t-Bu
Bu-t
O
t-Bu
O
Bu-t
t-Bu
O
(EtO)2P(O)
CH CH
CH CH
O
t-Bu
Bu-t
P(O)(OEt)2
Bu-t
t-Bu
I
Bu-t
t-Bu
HO
(EtO)2P(O)
CH CH
P(O)(OEt)2
II
OH
Bu-t
t-Bu
mixed with 5 ml of acetone and left at room tempera-
ture for crystallization with simultaneuos evaporation
of the solvents. After two days, crystals formed and
were washed with a small amount of acetone to give
0.11 g of a reddish orange product I, mp 305 308 C
(from acetone). Published data [4]: mp 310 311 C.
Found, %: C 83.25, 83.40; H 9.70, 9.95. C30H42O2.
Calculated, %: C 82.95; H 9.72.
II, mp 246 250 C (from toluene). Published data [7]:
mp 257 C. Found, %: P 8.85, 9.07. C38H64O8P2.
Calculated, %: P 8.73
1,2-Bis(2,5-di-tert-butyl-4-hydroxyphenyl)-1,2-
bis(diethoxyphosphinoyl)ethane (II). A solution of
1.06 g of 2,6-di-tert-butyl-4-(diethoxyphosphinoyl)-
methylene-2,5-cyclohexadienone, 0.4 g of water, and
2 drops of sulfuric acid in 10 ml of acetone were
refluxed for 1 h and left to stand uncovered at room
temperature for 15 days. The residue after evaporation
of volatile products was washed with water (2 5 ml)
and treated with hexane to obtain 0.07 g of a colorless
The acetone was evaporated, and the residue was
washed with water (3 5 ml) and dissolved in 10 ml
of ethanol. Two days later, crystals formed and were
filtered off to obtain 0.06 g of a colorless compound
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 10 2001

NEW DATA ON THE REACTION OF DIETHYL HYDROGEN PHOSPHITE
1549
product II, mp 248 252 C (from toluene). Found,
%: P 8.81, 8.95.
Prostranstvenno-zatrudnennye fenoly (Sterically Hin-
dered Phenols), Moscow: Khimiya, 1972.
4. Bruk, Yu.A. and Rachinskii, F.Yu., Zh. Obshch. Khim.,
The IR spectra of compounds I and II are identical
to the spectra of authentic samples, and mixed
samples give no melting point depression.
1964, vol. 34, no. 9, pp. 2983 2897.
5. Pudovik, A.N. and Gur’yanova, I.V., in Trudy 4th kon-
ferentsii Khimiya i primenenie fosfororganicheskikh
soedinenii (Proc. 4th Conf. on Chemistry and Applica-
tion of Organophosphorus Compounds), Moscow:
Nauka, 1972, pp. 164 173.
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Arkhipov, V.P., and Kopylova, L.Yu., Zh. Obshch.
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2. Gross, H., Seibt, H., and Keitel, I., J. Prakt. Chem.,
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 10 2001