The structure of side product in the synthesis of substituted 1,3-tropolones

Article abstract of DOI:10.1134/S1070428002120217

The structure of pyrocatechol p-toluenesulfonate resulting from the reaction between 3,5-di(tertbutyl)-1,2-benzoquinone and substituted 2-methylquinolines was proved by X-ray diffraction analysis. Pleiades Publishing, Inc. 2006.

Full text of DOI:10.1134/S1070428002120217

ISSN 1070-4280 Russian Journal of Organic Chemistry, 2006, Vol. 42, No. 2, pp. 275-277. Ó Pleiades Publishing, Inc. 2006.
Original Russian Text Ó V.V. Tkachev, S.M. Aldoshin, G.V. Shilov, Yu.A. Sayapin, V.N. Komissarov, V.I. Minkin, 2006, published in Zhurnal
Organicheskoi Khimii, 2006, Vol. 42, no. 2, pp. 290-292.
The Structure of Side Product in the Synthesis
of Substituted 1,3-Tropolones
V.V. Tkachev1, S.M.Aldoshin1, G.V. Shilov1, Yu.A. Sayapin2,
V.N. Komissarov2, and V.I. Minkin2
1Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moskow oblast’, 142432 Russia
e-mail: sma@icp.ac.ru
2Institute of Physical and Organic Chemistry at Rostov State University
Received December 6, 2004
Abstract—The structure of pyrocatechol p-toluenesulfonate resulting from the reaction between 3,5-di(tert-
butyl)-1,2-benzoquinone and substituted 2-methylquinolines was proved by X-ray diffraction analysis.
DOI: 10.1134/S1070428002120217
We showed formerly [1, 2] that 3,5-di(tert-butyl)-1,2-
benzoquinone (I) reacted with substituted 2-methyl-
quinolines IIa–IIf to afford 2-(quinolin-2-yl) derivatives
of 1,3-tropolone IIIa–IIIf. Dihydrotropolones IVa–IVf
should form intermediately in this process to be
subsequently dehydrated with excess quinone I giving
tropolones IIIa–IIIf and 3,5-di(tert-butyl)pyrocatechol
(V) (Scheme 1).
the reaction mixture and characterized by elemental
analysis, 1H NMR spectroscopy, and by comparison with
an authentic sample prepared by an independent synthesis
pyrocatechol p-toluenesulfonate (VII) (Scheme 2).
Increasing the amount of p-toluenesulfonic acid (VI)
in the synthesis of tropolones IIIa–IIIf resulted in larger
yield of ester VII. The formation of ester VII confirms
the mechanism we assumed in Scheme 1. The structure
of ester VII established by X-ray diffraction analysis is
shown on the figure.
The reaction is catalyzed with p-toluenesulfonic acid
(VI). Alongside tropolones IIIa–IIIf we isolated from
Scheme 1.
&O
%XꢀW
&O
1
5
2
2
2
5
5
Wꢀ%X
Wꢀ%X
+
+
1
Wꢀ%X
0H
2+
0H
,,D ,,H
,
,9D ,9H
&O
5
%XꢀW
5
5
2
2+
2+
Wꢀ%X
1
ꢁ>+@
Wꢀ%X
0H
2+
Wꢀ%X
,,,D ,,,H
9
II, III, R1 = R2 = R3 = H (a); R1 = R3 = H, R2 = Me (b); R1 = R2 = H, R3 = Me (c); R1 = NO2, R2 = R3 = H (d); R1 = NO2, R2 = Me,
R3 = H (e); R1 = NO2, R2 = H, R3 = Me (f).
275

TKACHEV et al.
276
Scheme 2.
%XꢀW
2
6
2
6
2+
9
9
+2
0H
&O
0H
+ 2
+&O
2
2
Wꢀ%X
262
0H
9,
9,,
9,,,
°
2.28 A . At the same time the intramolecular contacts
between the O4 and the nearest thereto hydrogens on
Note that the p-toluenesulfonate part of the molecule
has a traditional structure similar, e.g., to that in the
2-chlorophenyl 4-methylbenzenesulfonate analog [3]
°
the atoms C12 and C13 are equal to 2.31 and 2.33 A . The
second tert-butyl group (on C7) is disordered by two
positions distinguished by the angle of the turn around
the C3–C7 bond of 60°, populated to 85% (the bonds shown
by full lines) and to 15% (bonds shown by dashed lines).
For the more populated configuration the torsion angle
C2C3C7C10 amounts to 0.08°, and in the less populated
one exists the torsion angle C4C3C7C92 of 1.4°. In the
first configuration the shortest distances between
hydrogens on atoms C2 and C4 and the corresponding
hydrogen atoms attached to C8, C9, and C10 fall into the
...
where the plane of the benzene ring C15 C20 projected
along the bond has the syn-orientation with an orthogonal
position of the S–O3 bond. The torsion angle C15SO3C1
equals 54.5°, and the angle O3SC15C16 is 92.6°.
The atoms O2, S, O3, and C1 are located in the same
°
plane within accuracy of 0.055Aforming a torsion angle
of 170°. The distances S–O1 and S–O2 are equal to
1.413(1) and 1.416(1), S–O3 and S–C15 are 1.601(1) and
°
1.742(1) A respectively. The angle O3SC15 equals
103.1(1), the angle O1SO2 is 119.5(1)°, the other angles
around the sulfur atom are close to tetrahedral. The atoms
°
range 2.19–2.34A. Taking into consideration the similarity
°
of the torsion angles for both configurations the analogous
distances between hydrogen atoms in the less populated
configuration presumably also fall into a like range, and
the difference in occupancy cannot be ascribed to the
intramolecular sterical reasons.
C1,C2,C3,C4,C5,C6,C7,C11,O3 within 0.015 A are located
in the same plane that is turned around the C1–O3 bond
forming torsion angles SO3C1C2 and SO3C1C6 of 77 and
106° respectively.
The carbons of the tert-butyl group on the C11 atom
are oriented in such manner with respect to the
pyrocatechol ring that the torsion angle C4C5C11C14 is
equal to 4.2° resulting in shortened intramolecular contacts
between the hydrogen attached to C4 atom and the
nearest hydrogen atoms on C14 amounting to 2.23 and
In the single crystal exist pairs of intermolecular hydro-
gen bonds between hydrogen of the OH group from one
...
molecule and O22 of the second (the distance O22 HO4
°
equals 1.852A, angle SO22 HO4 is 171.8°, and angle O22
HO4 is 146.7°) resulting in formatiom of dimer associates.
EXPERIMENTAL
1H NMR spectra were registered on a spectrometer
Varian Unity-300.
X-ray diffraction analysis of compound VII. Unit
cell parameters of the crystal of ester VII (C21H28O4S)
and the three-dimensional set of reflections intensities
were obtained on a diffractometer KUMA-DIFFRAC-
TION KM-4 (MoKa-radiation, graphite monochromator)
for an isometric single crystal of an arbitrary form with
a radius ~0.025 mm. Monoclinic crystal with parameters
a 9.259(3), b 10.658(3), C 21.222(12) A° , b 91.22(5)°,
°
V 2093.8(15) A3
r
,
M 376.49, space group P21 /C, Z 4,
calc 1.194 g/cm3. The intensity of 4375 reflections were
measured in the independent part of the reciprocal space
(2q £ 52.12°) by means of w/2q-scanning. On excluding
the systematically quenched reflections the operative
Structure of ester VII with numbering of atoms. The bonds
with the carbons of the CH3 groups in the less occupied positions
are shown by dashed lines.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 2 2006

THE STRUCTURE OF SIDE PRODUCT IN THE SYNTHESIS
277
S 8.52. Reactions with quinolines IIa, IIb, IId–IIf were
array of the measured reflections amounted to 2993 with
carried out in the same way.
I > 2s(I).
b. A solution of 1.1 g (5 mmol) of pyrocatechol V,
1.1 g (5 mmol) of sulfonyl chloride VIII in 5 ml of pyridine
was heated at 40–45°C for 2 h. The reaction mixture
was diluted with water. The oily precipitate was ground
till crystallization, filtered off, and washed with water,
dissolved in a mixture chloroform–hexane, 1:1, and
subjected to chromatography on a column (30´1.5 cm)
packed with aluminum oxide, eluent chloroform–hexane,
1:1. The first fraction was collected. On removing the
solvent we obtained 0.52 g (28%) of phenol VII. After
recrystallization from 2-propanol the melting point was
The structure of ester VII was solved by the direct
method and refined by full-matrix least-squares procedure
with respect to F2 with the use of SHELXL-97 software
[4] in the anisotropic approximation for thermal oscillations
of the nonhydrogen atoms excluding three carbon atoms
in disordered positions with 15% occupancy; here the
isotropic approximation was applied.All hydrogen atoms
in the structure were found from the difference synthesis
and were refined in the isotropic approximation (for the
hydrogens in the disordered CH3 groups with occupancy
of 85% the thermal parameter was set at 0.08). The final
value of the R-factor is 4.2% (7.6% for 4151 reflections),
GOF 1.074.
1
154–156°C. The elemental analysis and H NMR
spectrum were identical to the data for compound obtained
by procedure a. No depression of the melting point was
observed in the mixed sample.
2-(p-Tolylsulfoxy)-4,6-di(tert-butyl)-phenol (VII).
a. A solution of 1 g (5 mmol) of compound IIc, 2.2 g
(10 mmol) of quinone I, and 0.9 g (5 mmol) of sulfonic
acid VI in 10 ml of o-xylene was boiled for 2 h. On cooling
the solution was applied to a column packed with aluminum
oxide, and the products were separated by elution with
a mixture chloroform–hexane, 1:2. The bright-yellow frac-
tion containing tropolone IIIc was isolated as described
in [1]. The next reddish fraction was eluted with chloro-
form. The solvent was distilled off, the residue was re-
crystallized from 2-propanol. Yield of the colorless
crystalline compound VII 0.1 g (5% calculated on sulfonic
The study was carried out under financial support of
the Russian Foundation for Basic Research (grant
no. 05-03-32081-a), Intrenational Foundation “Scientific
Partnership”, ISTC 2117, and of the President of the
Russian Federation (grant supporting the leading scientific
schools NSh-945.2003.3).
REFERENCES
1. Komissarov, V.N., Bang, D.N., Minkin, V.I.,Aldoshin, S.M.,
Tkachev, V.V., and Shilov, G.V., Mendeleev Commun., 2003,
vol. 13, p. 219.
2. Sayapin, Yu.A., Komissarov, V.N., Minkin, V.I., Tka-
chev, V.V.,Aldoshin, S.M., and Shilov, G.V., Zh. Org. Khim.,
2005, vol. 41, p. 1571.
3. Vembu, N., Nallu, M., Garrison, J., and Young, W.J., Acta
Crystallogr., 2003, vol. 59, p. 503.
4. Sheldrick, G.M., The SHELX-97, Manual, Gottingen: Univ.
of Gottingen, 1997.
1
acid VI), mp 154–156°C. H NMR spectrum (CDCl3),
d, ppm: 1.13 s [9H, C4(CH3)3], 1.33 s [9H, C6(CH3)3],
2.43 s (3H, 4'-CH3), 5.80 s (1H, 1-OH), 6.56 d (1H,
5-H, J 2.37 Hz), 7.11 d (1H, 3-H, J 2.37 Hz), 7.3–7.7 m
(4H, 2',3',5',6'-H, J 8.08 Hz). Found, %: C 66.73; H 7.39;
S 8.55. C21H28O4S. Calculated, %: C 66.99; H 7.50;
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 2 2006