Russian Chemical Bulletin, International Edition, Vol. 62, No. 10, pp. 2265, October, 2013
2265
Formation of 3,3´,5,5´ꢀtetra(tertꢀbutyl)diphenoquinone and
3,3´,5,5´ꢀtetra(tertꢀbutyl)ꢀ4,4´ꢀdihydroxybiphenyl in the reaction of
2ꢀ(acetylamino)ꢀ3ꢀ[3´,5´ꢀdi(tertꢀbutyl)ꢀ4´ꢀhydroxyphenyl]propanoic acid
with thionyl chloride
A. A. Volod´kin, L. N. Kurkovskaya, G. E. Zaikov, and S. M. Lomakin
N. M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences,
4 ul. Kosygina, 119991 Moscow Russian Federation.
Eꢀmail: chembio@sky.chph.ras.ru
Thionyl chloride is a reagent, which reacts with amino
acid acetyl derivatives to yield corresponding acyl chloꢀ
rides. However, a reaction of 2ꢀ(acetylamino)ꢀ3ꢀ[3´,5´ꢀ
di(tertꢀbutyl)ꢀ4´ꢀhydroxyphenyl]propanoic acid (1) in soꢀ
lution of thionyl chloride gave 3,3´,5,5´ꢀtetra(tertꢀbutyl)ꢀ
4,4´ꢀdihydroxybiphenyl (2) and 3,3´,5,5´ꢀtetra(tertꢀbutyl)ꢀ
diphenoquinone (3), rather than expected 2ꢀ(acetylꢀ
amino)ꢀ3ꢀ[3´,5´ꢀdi(tertꢀbutyl)ꢀ4´ꢀhydroxyphenyl]propꢀ
anoyl chloride (Scheme 1). Formation of compounds 2
and 3 is usually observed under conditions of the oxidative
condensation of 2,6ꢀdi(tertꢀbutyl)phenol and its certain
derivatives.1—4 Therefore, it can be suggested that the forꢀ
mation of compounds 2 and 3 in the reaction of acid 1
with thionyl chloride involves a redꢀox process.
The ratio of the oxidation products of 2,6ꢀdi(tertꢀ
butyl)phenol or its derivatives depends on the nature of
the oxidant, reaction conditions, and a possibility of formꢀ
ing complexes with protonꢀcontaining components. It can
be suggested that under the oxidation conditions, acid 1
initially forms a phenoxyl radical, which recombinates to
form compound 2. In the excess of thionyl chloride, comꢀ
pound 2 is oxidized to diphenoquinone 3.
1
H NMR spectra were recorded on a Bruker AvanceIIIꢀ500
(solvent CDCl3).
Thionyl chloride (5 mL) was added to acid 1 (3.35 g,
0.01 mol) at 18 C, after standing of the mixture for ~10 min, an
excess of SOCl2 was evaporated, water (30 mL) and toluene
(40 mL) were added to the residue. A mixture of compounds 2
and 3 was obtained from the organic phase, reflux of which in
EtOH (25 mL) gave a solution and an insoluble residue of the
crystalline diphenoquinone 3. The yield was 0.9 g (44.4%), m.p.
240—241 C (cf. Ref. 4: m.p. 240—241 C). 1H NMR, : 1.40
(s, 36 H, But); 7.70 (s, 4 H, ring). After evaporation of the solꢀ
vent from the ethanolic solution, the residue was recrystallized
from nꢀhexane to obtain compound 2 (1.1 g, 53.6%), m.p.
184—185 C (cf. Ref. 5: m.p. 185 C). 1H NMR, : 1.52 (s, 36 H,
But); 5.19 (s, 2 H, OH); 7.29 (s, 4 H, Ar). The individuality of
compounds 2 and 3 was confirmed by HPLC using a comparison
with the authentic samples.
Scheme 1
References
1. K. Ley, Angew. Chem., 1958, 70, 74.
2. L. Paquete, W. Farley, J. Org. Chem., 1967, 32, 2718
3. C. Cook, E. English, B. Wilson, J. Org. Chem., 1958, 23, 755.
4. E. Muller, A. Rieker, R. Mayer, K. Scheffler, Lieb. Ann.
Chem., 1961, 645, 36.
5. M. Kharasch, B. Joshi, J. Org. Chem., 1957, 22, 1439.
Received April 15, 2013;
in revised form June 25, 2013
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2265, October, 2013.
1066ꢀ5285/13/6210ꢀ2265 © 2013 Springer Science+Business Media, Inc.