Reaction of Tetramethylcalix[4]resorcinolarene with 3,5-Di-tert-butyl-4- hydroxybenzyl Acetate

Article abstract of DOI:10.1023/A:1026013430106

Upper-rim modification of tetramethylcarix[4]resorcinolarene with 3,5-di-tert-butyl-4-hydroxybenzyl fragments is accompanied by unusual decomposition of the macroring in the modified product with formation of 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)r

Full text of DOI:10.1023/A:1026013430106

Russian Journal of Organic Chemistry, Vol. 39, No. 5, 2003, pp. 689 691. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 5, 2003,
pp. 735 737.
Original Russian Text Copyright
2003 by Bukharov, Nugumanova, Mukmeneva, Teregulova, Burilov, Pudovik, Nikolaeva, Kasymova, Konovalov.
Reaction of Tetramethylcalix[4]resorcinolarene
with 3,5-Di-tert-butyl-4-hydroxybenzyl Acetate
S. V. Bukharov, G. N. Nugumanova, N. A. Mukmeneva, E. A. Teregulova,
A. R. Burilov, M. A. Pudovik, I. L. Nikolaeva, E. M. Kasymova, and A. I. Konovalov
Kazan State Technological University, Kazan, Tatarstan, Russia
Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center, Russian Academy of Sciences,
ul. K. Marksa 68, Kazan, 420015 Tatarstan, Russia
Received November 10, 2002
Abstract Upper-rim modification of tetramethylcalix[4]resorcinolarene with 3,5-di-tert-butyl-4-hydroxy-
benzyl fragments is accompanied by unusual decomposition of the macroring in the modified product with
formation of 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)resorcinol.
Study of the antioxidizing properties of calix[4]-
resorcinolarene I and some its derivatives showed
the possibility for creation of a new group of highly
efficient calixarene-based inhibitors of thermooxida-
tive polymer degradation [1]. Modification of calix-
arene I through introduction of sterically hindered
phenolic fragments into the aromatic rings may be
promising from the viewpoint of increasing the anti-
oxidizing activity.
We have studied the reaction of calix[4]resorcinol-
arene I with 3,5-di-tert-butyl-4-hydroxybenzyl acetate
(II); the use of the latter makes it possible to intro-
duce sterically hindered phenolic fragments into
molecules of various compounds [2]. The reaction was
carried out in the presence of a strong mineral acid
(HClO4, H2SO4), and it led to formation of a mixture
containing 70% of 2,4,6-tris(3,5-di-tert-butyl-4-hy-
droxybenzyl)resorcinol (III) and 30% of 5,11,17,19-
Scheme 1.
1070-4280/03/3905-0689$25.00 2003 MAIK Nauka/Interperiodica

690
BUKHAROV et al.
Scheme 2.
tetrakis(3,5-di-tert-butyl-4-hydroxybenzyl)-4,6,10,12,-
16,18,22,24-octahydroxy-2,8,14,20-tetramethylpenta-
cyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25),3,5,7(28),-
For example, bis(3,5-di-tert-2-hydroxy-butylphenyl)-
methane and bis(3-tert-butyl-2-hydroxy-5-methyl-
phenyl)methane are stable toward benzyl acetate II in
formic acid. The stability of calixresorcinolarene I to
mineral acids [3] may be explained by differences in
the supramolecular structure of compounds I and IV.
9,11,13(27),15,17,19(26),21,23-dodecaene (IV).
When the reaction was performed in the presence
of formic acid as acid catalyst (which promotes fast
and quantitative transformation of benzyl acetate II
into benzyl formate V), the product ratio considerably
changed: the mixture contained 30% of III and 70%
of IV. The formation of compound III in the reaction
of calixarene I with benzyl acetate II seems to be
surprising. This is the first example of cleavage of
the calix[4]resorcinolarene macroring by the action of
electrophile. Taking into account that such cleavage
does not occur in the binary system calixarene I per-
chloric (or formic) acid, we presume that compound
III is formed as a result of exhaustive benzylation
of calixarenes I and/or IV with benzyl cation A
generated during the process (Scheme 2). In fact, after
storage of a solution of compounds IV and II (at
a ratio of 1:8) in acetone in the presence of perchloric
acid, signals belonging to calixarene IV [(CDCl3), ,
The structure of products III and IV was proved
1
by the H and 13C NMR spectra and by independent
synthesis of compound III from resorcinol and benzyl
acetate II.
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded on
a Varian Gemini 200 spectrometer at 200 (1H) and
50 MHz (13C) using the solvent signals as reference
(CDCl3, acetone-d6).
2,4,6-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-
resorcinol (III). a. To a solution of 1 g (0.002 mol)
of calixarene I and 4.1 g (0.0148 mol) of benzyl
acetate II in 20 ml of acetone we added 0.08 ml of
72% perchloric acid. The mixture was kept for 24 h
at 20 C and poured into water. The precipitate was
filtered off, washed with water until neutral reaction,
and dried for 2 days at 20 C. We thus obtained 3.4 g
3
ppm: 1.74 d (12H, Me, J = 7.0 Hz), 4.60 q (4H, CH,
3J = 7.0 Hz), 6.34 s (8H, OH)] disappear almost com-
pletely from the 1H NMR spectrum of the mixture, but
those corresponding to compound III appear, , ppm:
3.80 s (4H, CH2), 3.92 s (2H, CH2), 4.85 s (2H, OH),
6.93 s (1H, Harom). An analogous pattern was observed
for dilute solutions of IV and II in formic acid.
1
of a product which, according to the H NMR data,
was a mixture of compounds III and IV at a ratio of
70:30. By recrystallization from hexane we isolated
1.2 g (35%) of compound III, mp 153 154 C; pub-
1
lished data [3]: mp 151 154 C. H NMR spectrum
Decomposition of the calixarene ring, which was
accompanied by disappearance of the methyl proton
(CDCl3), , ppm: 1.42 s (54H, CMe3), 3.80 s (4H,
CH2), 3.92 s (2H, CH2), 4.85 s (2H, OH), 5.09 s (1H,
OH), 5.16 s (2H, OH), 6.93 s (1H, HB), 7.12 s (1H,
HA). Found, %: C 79.85; H 9.70. C51H72O5. Calcu-
lated, %: C 80.10; H 9.42.
b. To a solution of 70 g (0.252 mol) of ester II
and 9.23 g (0.084 mol) of resorcinol in 140 ml of
acetic acid we added under stirring at 50 C 0.35 ml
of 72% of perchloric acid in a dropwise manner. The
mixture was heated for 1 h and was then stirred for
3 h at room temperature. The precipitate was filtered
off, washed with a small amount of acetic acid and
with water, and dried in air. We thus obtained 55 g
(85.5%) of compound III with mp 153 154 C.
doublet at
1.74 ppm and CH proton quartet at
4.60 ppm, also occurred when a solution of calix-
arene IV in formic acid containing no acetate II was
stored for several days. In this case, the process was
slower.
Thus we can conclude that the reaction of calix-
arene I with benzyl acetate II gives compound III as
a result of cleavage of the calixarene macroring in
product IV by the action of electrophiles: benzyl
carbocation A and acid catalyst. Presumably, the
observed sensitivity to electrophiles under mild condi-
tions is a specific property of resorcinol systems.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 5 2003

REACTION OF TETRAMETHYLCALIX[4]RESORCINOLARENE
691
5,11,17,19-Tetrakis(3,5-di-tert-butyl-4-hydroxy-
benzyl)-4,6,10,12,16,18,22,24-octahydroxy-2,8,14,-
Transformations of calixarene IV in acid
5
medium. A solution of 0.1 g (7 10 mol) of calix-
4
20-tetramethylpentacyclo[19.3.1.13,7.19,13.115,19]-
octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),-
21,23-dodecaene (IV). Formic acid, 65 ml, was added
to a solution of 3 g (0.0055 mol) of calixarene I and
6.9 g (0.0248 mol) of ester II in 55 ml of acetone.
The mixture was kept for 24 h at 20 C, poured into
100 ml of water, and neutralized with a solution of
sodium hydrogen carbonate to pH 5 6. The precipitate
was filtered off, washed with water, and dried in air.
We obtained 7.75 g of a product which, according to
arene IV and 0.155 g (5.6 10 mol) of ester II in
10 ml of acetone and 10 ml of formic acid (or in
10 ml of acetone containing one drop of perchloric
acid) was kept for 24 h at 20 C, poured into water,
and neutralized with a solution of NaHCO3. The pre-
cipitate was filtered off, washed with water, and dried.
The product was analyzed by 1H NMR spectroscopy.
Transformation of calixarene IV in formic acid
in the absence of ester II was effected as described
above. The mixture was kept for 6 days at 20 C.
Calixarene I did not change under these conditions,
as well as in acetone in the presence of perchloric
acid, and it was recovered from the reaction mixture.
1
the H NMR data, was a mixture of compounds III
and IV at a ratio of 30:70. The product was dissolved
in 25 ml of benzene, and 170 ml of hexane was added
to precipitate 2.6 g (33%) of compound IV, mp 230 C
This study was financially supported by the Rus-
sian Foundation for Basic Research (project no. 02-
03-33037).
1
(decomp.). H NMR spectrum, , ppm: in CDCl3:
3
1.39 s (72H, CMe3), 1.77 d (12H, Me, J = 7.0 Hz),
3
3.89 s (8H, CH2), 4.60 q (4H, CH, J = 7.0 Hz),
5.08 s (4H, OH), 6.34 s (8H, OH), 7.00 s (8H, HA),
REFERENCES
7.33 s (4H, HB); in acetone-d6: 1.37 s (72H, CMe3),
3
1.73 d (12H, Me, J = 7.0 Hz), 3.89 s (8H, CH2),
1. Ehrhardt, D., Gummi, Fasern Kunststoffe, 1992,
vol. 45, p. 231; Ehrhardt, D., Gummi, Fasern Kunst-
stoffe, 1992, vol. 45, p. 358; FRG Patent no. 290427,
1991; Chem. Abstr., 1991, vol. 115, no. 258104h;
FRG Patent no. 291902, 1991; Chem. Abstr., 1991,
vol. 115, no. 258105j.
3
4.60 q (4H, CH, J = 7.0 Hz), 5.72 s (4H, OH), 7.18 s
(8H, HA), 7.52 s (4H, HB), 7.88 s (8H, OH). 13C NMR
1
spectrum (CDCl3), , ppm: 20.5 q (C11, JCH
=
125.0 Hz), 28.3 d (C10, JCH = 130.0 Hz), 29.4 t (C5,
1
1JCH = 90.0 Hz), 30.2 q (CMe3, JCH = 120.0 Hz),
1
2. Bukharov, S.V., Nugumanova, G.N., and Mukmene-
1
34.3 s (CMe3), 114.0 s (C8), 121.6 d (C9, JCH
=
va, N.A., Russ. J. Gen. Chem., 1998, vol. 68, p. 1894.
150.0 Hz), 125.0 d (C3, JCH = 150.0 Hz), 125.5 s
1
3. Tunstad, L.M., Tucker, J.A., Dalcanale, E., Weiser, J.,
Bruant, J.A., Sherman, J.C., Helgeson, R.C.,
Knobler, C.B., and Cram, D.J., J. Org. Chem., 1989,
vol. 54, p. 1305.
(C6), 128.9 s (C4), 136.5 s (C2), 149.0 s (C7), 152.6 s
(C1). Found, %: C 77.65; H 8.65. C92H120O12. Calcu-
lated, %: C 77.97; H 8.47.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 5 2003