Thermal rearrangement of 1-(1-methyl-2-butenoxy)-4-methoxybenzene

Full text of DOI:10.1134/S107036320903030X

ISSN 1070-3632, Russian Journal of General Chemistry, 2009, Vol. 79, No. 3, pp. 513–514. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © E.V. Kluchareva, E.V. Ershova, M.Yu. Vozhdaeva, E.A. Kantor, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 3,
pp. 523–524.
LETTERS
TO THE EDITOR
Thermal Rearrangement
of 1-(1-Methyl-2-Butenoxy)-4-methoxybenzene
E. V. Kluchareva, E. V. Ershova, M. Yu. Vozhdaeva, and E. A. Kantor
Ufa State Oil Technical University,
ul. Kosmonavtov 1, Ufa, 450062 Russia
e-mail: e.kluchareva@mail.ru
Received March 27, 2008
DOI: 10.1134/S107036320903030X
Thermal rearrangement of allyl ethers of phenols is
the classical example of intramolecular Claisen
rearrangement (3,3-sigmatropic shift) [1]. As known,
the position of methoxy group in the aromatic ring
affects the reaction mechanism. 1-(1-Metyl-2-
butenoxy)-4-methoxybenzene undergoes the intramo-
lecular rearrangement while 1-(1-methyl-2-butenoxy)-
3-methoxybenzene takes part not only in the
intramolecular process, but also in the intermolecular
reaction proceeding with the preliminary cleavage of
O–C bond [2]. Rearranement of 1-(1-methyl-2-buten-
oxy)-2-meth-oxybenzene I was not described before.
methyl-2-butenyl)phenol III in the 4:1 ratio and
insignificant amounts of 2-methoxy-4,6-di-(1-methyl-
2-butenylphenol IV and 2-methoxyphenol V were
found in the reaction products. Presence of
dialkylphenol IV and phenol V may be regarded as the
evidence of the intermolecular transfer of alkenyl
fragment of molecules I, II or III to the molecules II
or III (Scheme 1).
Reaction mixture was analyzed by chromatomass-
spectrometry (Agilent, HP-SMS 30×0.25×0.25 column;
column temperature 30–250°C, heating rate 20°C/min
in the range 30–60°C and 6°C/min in the range 60–
250°C; injection temperature 250°C, ion source
temperature 230°C; quadrupole analyzer temperature
150°C, ionization energy 70 eV). Mass spectra, m/e
We have carried out rearranement of the ether I at
heating (200°C, dodecane, 1 h, argon). 2-Methoxy-6-
(1-methyl-2-butenyl)phenol II and 2-methoxy-4-(1-
Scheme 1.
CH3
OH
CH3
OH
H3CO
O
CH3
H3CO
H3CO
CH3
+
H3C
CH3
III
I
II
OH
CH3
OH
H3CO
H3CO
CH3
+
+
H3C
CH3
IV
V
513

KLUCHAREVA et al.
514
(Irel, %): I: 8.971 min, 124(100), 109(49), 69(28), 41
(19), 81(8); II: 9.981 min, 192(100), 145(75), 177(42),
117(38), 163(20); III: 10.148 min, 192(100), 145(77),
177(45), 117(40), 163(17); IV: 12.750 min, 69(100),
260(68), 245(25), 191(19), 159(19); V: 5.83 min, 109
(100), 124(91), 81(60), 53(13), 39(7).
to their boiling points. Combination of these two
factors permits a conclusion that the presented iden-
tification of isomers is quite reliable.
REFERENCES
1. Aleksandrovam E.K., Bunina-Krivorukovam L.I., Mo-
shinskayam A.V., and Bal’yan, Kh.V., Zh. Org. Khim.,
1974, vol. 10, no. 5, p. 1039.
2. Shornik, N.A., Aleksandrova, E.K., and Bunina-Kri-
vorukova, L.I., Zh. Org. Khim., 1984, vol. 10, no. 10,
p. 2245.
Identification of isomers was based on the cal-
culated activation energy data. More probable forma-
tion of isomer corresponds to the larger area of the
chromatographic peak. Besides, the phase used
provides the order of elution of analytes corresponding
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 3 2009