Unusual inhibition effect of 1-(1-naphthyl)-1-methylethylhydroperoxide on the liquid-phase oxidation of isopropylarenes. GC-MS and theoretical studies of the thermal decomposition of 1-naphthyl- and 1-anthryl-1- methylethylhydroperoxides

Article abstract of DOI:10.1021/op0502351

All five possible 1-aryl-1methylethylhydroperoxides derived from naphthalene and anthracene were synthesized and their thermal decomposition in GC-MS conditions was investigated to explain the unusual inhibition effect of 1-(1-naphthyl)-1-methylethylhydroperoxide on the liquid-phase oxidation of isopropylarenes. 2-(1-Aryloxy)propenes were identified as the main decomposition products of 1-(1-naphthyl)-1-methylethylhydroperoride and 1-(1-anthryl)-1- methylethylhydroperoxide. The relatively unstable 2-aryloxypropenes have thus far never been described as thermal decomposition products of 1-aryl-1-methylethylhydroperoxides. The plausible mechanism of the formation of 2-(1-aryloxy)propenes was proposed on the basis of AM-1 calculations of the possible rearrangement paths of the alkoxy radicals derived from the investigated hydroperoxides. The mechanism explains the inhibition effect of 1-(1-naphthyl)-1-methylethylhydroperoxide on the oxidation of isopropylarenes.

Full text of DOI:10.1021/op0502351

Organic Process Research & Development 2006, 10, 289−295
Unusual Inhibition Effect of 1-(1-Naphthyl)-1-methylethylhydroperoxide on the
Liquid-Phase Oxidation of Isopropylarenes. GC-MS and Theoretical Studies of
the Thermal Decomposition of 1-Naphthyl- and
1-Anthryl-1-methylethylhydroperoxides
Roman Mazurkiewicz,*,† Jan Zawadiak,‡ Beata Orlin´ska,‡ Barbara Hefczyc,‡ Zbigniew Stec,‡ Mirosława Grymel,†
Piotr Fiedorow,§ and Henryk Koroniak§
Department of Organic Chemistry, Biochemistry and Biotechnology, Silesian UniVersity of Technology, Krzywoustego 4,
44-100 Gliwice, Poland, Department of Organic Chemical Technology and Petrochemistry, Silesian UniVersity of
Technology, Krzywoustego 4, 44-100 Gliwice, Poland, and Faculty of Chemistry, Adam Mickiewicz UniVersity,
60-780 Poznan´, Poland
Scheme 1. 2-Naphthol synthesis by Hock’s method
Abstract:
All five possible 1-aryl-1methylethylhydroperoxides derived
from naphthalene and anthracene were synthesized and their
thermal decomposition in GC-MS conditions was investigated
to explain the unusual inhibition effect of 1-(1-naphthyl)-1-
methylethylhydroperoxide on the liquid-phase oxidation of
isopropylarenes. 2-(1-Aryloxy)propenes were identified as the
main decomposition products of 1-(1-naphthyl)-1-methylethyl-
hydroperoxide and 1-(1-anthryl)-1-methylethylhydroperoxide.
The relatively unstable 2-aryloxypropenes have thus far never
been described as thermal decomposition products of 1-aryl-
1-methylethylhydroperoxides. The plausible mechanism of the
formation of 2-(1-aryloxy)propenes was proposed on the basis
of AM-1 calculations of the possible rearrangement paths of
the alkoxy radicals derived from the investigated hydroperox-
ides. The mechanism explains the inhibition effect of 1-(1-
naphthyl)-1-methylethylhydroperoxide on the oxidation of
isopropylarenes.
this synthesis. The technical 2IPN used in oxidation process
as a raw material is contaminated by a small amount (5-
10%) of 1-isopropylnaphthalene (1IPN), which is difficult
to remove. The 1IPN present in the raw material, after
oxidation to 1-(1-naphthyl)-1-methylethylhydroperoxide 1a,
reduces the reaction rate and results in a lower yield and
poorer selectivity in the production of hydroperoxide 1b.
The reported data on oxidation of 1IPN are controversial.
Some investigators claim that 1IPN fails to undergo oxidation
with oxygen,7,8 whereas others maintain that it undergoes
oxidation but at a rate about 5-10 times lower than that of
the oxidation of 2IPN.9,10
Our kinetic measurements of the rates of oxidation of
1IPN and 2IPN in the presence of 2,2′-azo-bis-isobutyrylni-
trile and 1,1′-azo-bis-(1-cyclohexanecarbonitrile) as initiators
at 75, 100, and 110 °C showed that 1IPN undergoes free-
radical oxidation with oxygen, but the reaction rate was 10-
12 times lower than that of 2IPN. On the other hand, long-
duration trials of oxidizing 1IPN with oxygen were a
complete failure.11
Free-radical chain oxidation of hydrocarbons is well-
known to be affected by the resulting hydroperoxides. As a
result of the thermal decomposition of hydroperoxides into
free radicals, the process becomes autocatalytic in its nature.
We have demonstrated that hydroperoxide 1b really acts as
an initiator of free-radical oxidation of isopropylarenes. We
have also shown that, in contradistinction to 1b, hydroper-
oxide 1a inhibits the free-radical oxidation of isopropylarenes
with oxygen.11
Introduction
The method of 2-naphthol synthesis from 2-isopropyl-
naphthalene (2IPN) (Scheme 1), analogous to that used to
produce phenol from cumene (Hock’s process),1-6 in com-
parison to the conventional fusion method, is environmentally
friendly and offers the advantage of consuming less energy
and producing acetone as coproduct.
Free-radical oxidation of 2IPN with oxygen to 1-(2-
naphthyl)-1-methylethylhydroperoxide 1b is a key stage of
* To
whom
correspondence
should
be
addressed.
E-mail:
Roman.Mazurkiewicz@polsl.pl. Fax: +48 32 2372094. Telephone: +48 32
2371724.
† Department of Organic Chemistry, Biochemistry and Biotechnology, Silesian
University of Technology.
‡ Department of Organic Chemical Technology and Petrochemistry, Silesian
University of Technology.
The inhibition effect of hydroperoxide 1a on the oxidation
of isopropylarenes and the low oxidizability of 1IPN are
§ Faculty of Chemistry, Adam Mickiewicz University.
(1) Weissermel, K.; Arpe, H. J. Industrial Organic Chemistry; VCH Verlags-
gesellschaft: Weinheim, 1993; p 328.
(2) Boyaci, F. G.; Takac, S.; Calik, G.; O¨ zdamar, T. H. Appl. Catal. A. 2003,
(7) Decker, D.; Dettmeier, U.; Leupold, I. DGMK Conference: SelectiVe
Oxidations in Petrochemistry; Goslar, Germany, 1992.
238, 85.
(3) Boyaci, F. G.; Takac, S.; O¨ zdamar, T. H. Appl. Catal. A. 2000, 197, 279.
(4) Boyaci, F. G.; Takac, S.; O¨ zdamar, T. H. Appl. Catal. A. 1999, 183, 377.
(5) Takac, S.; Boyaci, F. G.; O¨ zdamar, T. H. Chem. Eng. J. 1998, 71, 37.
(6) Stec, Z.; Zawadiak, J.; Knips, U.; Zellerhoff, R.; Gilner, D.; Orlin´ska, B.;
Polaczek, J.; Tecza, W.; Machowska, Z. U.S. Patent 6,107,527, 2000.
(8) Farberov, M. I.; Bondarenko, A. W.; Shustovskaya, G. N. Dokl. Akad. Nauk
SSSR Khim. 1969, 187, 831.
(9) Hosaka, H.; Tamimoto, K. U.S. Patent 4,049,720, 1977.
(10) Heinze, A.; Lauterbach, G.; Pritzkow, W. J. Prakt. Chem. 1987, 239, 439.
(11) Zawadiak, J.; Stec, Z.; Orlin´ska, B. Org. Process Res. DeV. 2002, 6, 670.
10.1021/op0502351 CCC: $33.50 © 2006 American Chemical Society
Published on Web 02/09/2006
Vol. 10, No. 2, 2006 / Organic Process Research & Development
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289

Scheme 2. Typical reaction of 1-methyl-1-naphthylethyloxy
radical
Table 1. Thermal decomposition of hydroperoxides in
GC-MS conditions
untypical for isopropylarenes and the corresponding hydro-
peroxides. To find out the reasons of essential differences
in the chemical behaviour of hydroperoxides 1a and 1b, their
thermal stabilities as well as products of their decomposition
were compared.
yield of decomposition products [%]a
hydroperoxides alcohol ketone alkene aryloxypropene
Ar
1a-e
2a-e
3a-e
4a-e
5a-e
1-naphthyl
2-naphthyl
1-anthryl
2-anthryl
9-anthryl
1a
1b
1c
1d
1e
23.5
39.0
18.8
77.7
-
19.7
40.0
-
9.2
21.0
-
13.5
79.7
45.6
-
81.2
-
The differential scanning calorimetry experiments showed
that their thermal stabilities are similar; the temperatures of
maximum rates of decomposition (Tmax) of the 1a and 1b
are close to each other (197.5 and 193.6 °C, respectively).11
On the other hand, the composition of products of the thermal
decomposition of hydroperoxides 1a and 1b in liquid phase
(120 °C, 30 h, cumene solution, analysis by HPLC) exhibits
essential differences: hydroperoxide 1b undergoes decom-
position to 2-(2-naphthyl)-2-propanol (78%) and 2-acetyl-
naphthalene (22%), whereas 1a decomposes to the corre-
sponding alcohol and ketone in yields of only 44 and 6%,
respectively (Scheme 2), the other part of hydroperoxide 1a
(about 50%) being converted to an unidentified dark tarry
substance.11 We assume that the tarry substance is probably
formed as the result of the polymerization of some primary
product of decomposition of hydroperoxide 1a.
This result suggests that alkoxy radicals formed by
thermal decomposition of 1a also entered into reactions other
than the well-known reactions: hydrogen abstraction and
â-scission (Scheme 2). We also assume, that the other
products can affect disadvantageously the course of free-
radical oxidation process.
To get a more clear picture of the thermal decomposition
of hydroperoxides 1a and 1b and to avoid consecutive
transformations of primary decomposition products we
decided to investigate the thermal decomposition of these
hydroperoxides in GC-MS conditions. To acquire more
information on the dependence between the structure and
properties of hydroperoxides, we extended our investigations
on 1-(1-anthryl)-, 1-(2-anthryl)-, and 1-(9-anthryl)-1-meth-
ylethylhydroperoxides (1c, 1d, and 1e, respectively). We also
carried out semiempirical calculations of a few possible
rearrangement paths of the corresponding alkoxy radicals.
-
18.3
2.0
a Estimated from the area of the corresponding signals on GC.
In the case of hydroperoxide 1a we also detected some
unidentified compound with a plausible molecular ion at m/z
184 as the main product (Tables 1 and 2). We suspected
that the unidentified compound might be 2-(1-naphthyloxy)-
propene 5a. To verify this hypothesis we obtained this
compound by means of an independent synthesis (Scheme
3), and we stated that the MS spectrum of the synthesized
sample of aryloxypropene 5a was identical with the spectrum
of the decomposition product (Table 2).
A large amount of analogous 2-(1-anthryloxy)propene 5c
we also identified as the main product of the thermal
decomposition of hydroperoxide 1c; a small amount of
analogous compound was also detected in the decomposition
products of hydroperoxide 1e. 2-Anthryloxypropenes 5c and
5e were identified by comparing their MS spectra with the
spectrum of 2-(1-naphthyloxy)propene 5a; the spectra of
anthracene derivatives were very similar to the spectrum of
5a; the masses of all the prominent ions, however, were
higher by 50 Da, which corresponds exactly to the difference
between the molecular mass of anthracene and naphthalene
derivatives (Table 2).
It should be stressed, that, according to our best knowl-
edge, relatively unstable 2-aryloxypropenes 5 have thus far
not been described as thermal decomposition products of
1-aryl-1-methylethylhydroperoxides.
To find out the reasons for the essential differences in
the chemical behaviour of hydroperoxides 1a and 1b, we
carried out semiempirical AM-1 calculations of possible
rearrangement paths of alkoxy radicals derived from 1a and
1b.12 In this paper we extended such calculations for alkoxy
radicals derived from hydroperoxides 1c, 1d, and 1e (Table
3, Scheme 4).
Results and Discussion
The results of the thermal decomposition of hydroperox-
ides in GC-MS conditions have been gathered in Table 1.
The following three kinds of common products of thermal
decomposition of 1-aryl-1-methylethylhydroperoxides were
detected by means of the GC-MS method: 2-aryl-2-
propanols 2, acetylarenes 3, and 2-arylpropenes 4. They were
identified by comparing their MS spectra with the spectra
of synthesized authentic samples of the corresponding
compounds.
Considering several possible rearrangement paths of
alkoxy radicals which may lead to 2-aryloxypropanes 5, we
noticed that in the case of the 1-(1-naphthyl)-1-methylethoxy
radical the most energetically favoured transformation, with
(12) Fiedorow, P.; Koroniak, H.; Mazurkiewicz, R.; Zawadiak, J.; Orlin´ska, B.;
Stec, Z.; Grymel, M. Cent. Eur. J. Chem. 2006. In press.
290
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Vol. 10, No. 2, 2006 / Organic Process Research & Development

Table 2. Prominent peaks in the GC-MS spectra of 2-aryloxypropenes (EI, 70 eV)
other peaks of
relative abundance >10%
M+•
[M-C3H4]+• [M-C3H4-CO]+• [M-C3H5-CO]+ [M-C3H5-CO-C2H2]+
5aa 184 (40.1%)
144 (60.3%)
144 (63.9%)
194 (40.9%)
116 (82.9%)
116 (47.9%)
166 (35.2%)
115 (100%)
115 (100%)
165 (100%)
89 (26.5%)
89 (22.9%)
139 (19.3%)
169 (24.5%); 141 (29.2%);
63 (20.2%)
5ab 184 (33.6%)
5ca 234 (34.4%)
169 (10.0%); 141 (25.0%);
63 (22.9%)
219 (10.2%); 205 (29.1%);
191 (56.1%); 138 (19.3%);
114 (22.5%); 87 (18.0%);
75 (33.2%); 62 (36.1%);
5ea 234 (60.9%)
194 (95.1%)
166 (13.0%)
165 (100%)
139 (18.4%)
218 (10.8%); 203 (11.7%);
115(13.4%)
a Product of decomposition of the corresponding hydroperoxide. b The synthesized sample.
Scheme 3. Synthesis of 2-(1-naphthyloxy)propene 5a
mediate as the key step. This kind of rearrangement of alkoxy
radicals is well-known in free-radical chemistry.14 The second
pathway involves formation of a naphthofurane derivative
as an intermediate followed by its rearrangement to 2-(1-
naphthyloxy)propene 5a.
Both discussed pathways account for the formation of
2-(1-aryloxy)propenes 5 and 2-aryl-2-propanols 2 as the main
products of the decomposition of hydroperoxides 1a and 1c
in GC-MS conditions. The formation of only trace amounts
of 2-(9-aryloxy)propene 5e from hydroperoxide 1e can be
explained by assuming the following two reasons: (i) already
in the course of the synthesis and purification of 1e we
observed its proclivity to decompose to 2-(9-anthryl)propene
4e, probably caused by a steric hindrance around the
2-hydroperoxypropyl group, and (ii) formation of a planar
six-membered transition state for abstraction of hydrogen
from the peri position is, in the case of 1e, probably difficult
because of the steric interaction between two methyl groups
and the hydrogen atom at the second peri position.
an energy barrier of only 75 kJ/mol, consists of the
abstraction of hydrogen from the peri position of the naphthyl
group.12 A similar abstraction of hydrogen from ortho
positions in the cases of both the 1-(1-naphthyl)- and 1-(2-
naphthyl)-1-methylethoxy radicals is much more difficult
(energy barrier 130.7-138.2 kJ/mol). Very similar results
have been obtained for analogous alkoxy radicals with
1-anthryl and 2-anthryl substituents; also in this case the
abstraction of hydrogen from the peri position of the
neighbouring ring is strongly favoured (energy barrier only
54.9 kJ/mol compared with 112.3-126.8 kJ/mol for the
abstraction of hydrogen from ortho positions). This kind of
abstraction, involving the six-membered transition state,
seems to be generally more favourable compared with the
analogous transformation involving the five-membered tran-
sition state. Similar transformations of alkoxy radicals by
hydrogen abstraction involving the six-membered transition
state are known in the literature.13
Unfortunately, we were not able to find a stable structure
with all positive normal modes for the alkoxy radical derived
from hydroperoxide 1e.
Assuming that the first stage of the hydroperoxide 1a
rearrangement consists of the abstraction of hydrogen from
the peri position of the corresponding alkoxy radical, two
plausible pathways of its transformation to 2-(1-naphthy-
loxy)propene can be formulated as presented at Scheme 5.
The first pathway involves a 1,2-aryl migration from
carbon to oxygen via a three-membered oxirane-like inter-
In case of the thermal decomposition of hydroperoxide
1a carried out in liquid phase (in cumene as a solvent)
2-aryloxypropene 5a was also detected. A small amount of
5a was isolated by preparative thin-layer chromatography.
It suggests that, in the liquid phase as well as under GC-
MS conditions, the thermal decomposition products of 1-aryl-
1-methylethylhydroperoxides contain 2-aryloxypropenes.
However, when decomposition is carried out in liquid phase,
2-aryloxypropene probably undergoes radical polimerization
or hydrolysis, and therefore, its detection is difficult.
The inhibition effect of hydroperoxide 1a in the oxidation
of isopropylarenes may consist in terminating a free-radical
chain as a result of catching the RO• radicals in the
intermolecular hydrogen abstraction reaction (Scheme 5). The
inhibition effect of hydroperoxide 1a may also be a result
of hydrolysis of 2-(1-naphthyloxy)propene 5a to 1-naphthol
by trace amount of water. 1-Naphthol is a well-known
(13) Walling, Ch.; Padwa, A. J. Am. Chem. Soc. 1961, 83, 2207.
(14) Studer, A.; Bossart, M. Tetrahedron 2001, 57, 9667.
Vol. 10, No. 2, 2006 / Organic Process Research & Development
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291

Table 3. Hydrogen abstraction from ortho and peri positions of alkoxy radicals derived from
1-aryl-1-methylethylhydroperoxides (heat of formation of species in kJ/mol; AM1, RHF for openshell system)
derivative
1-naphthyl12
2-naphthyl12
1-anthryl
2-anthryl
position of hydrogen abstraction
and reaction path
peri
ortho
(B)
ortho
ortho
(B)
peri
ortho
(B)a
ortho
ortho
(B)a
(A)
(A)
(A)a
(A)a
substrate (R)
transition state
transition product (TP)
198.6
273.6
178.5
198.6
330.6
183.1
189.4
327.6
171.0
189.4
320.1
169.3
312.7
367.6
279.7
312.7
425.0
278.0
295.2
422.0
263.3
295.2
411.6
263.3
a The reaction path analogous to the corresponding reaction path for naphthyl derivatives (cf Scheme 4).
Scheme 4. Hydrogen abstraction from ortho and peri
positions of alkoxy radicals derived from
1-naphthyl-1-methylethylhydroperoxides
peroxides with hydrogen at the peri position in relation to
the 2-hydroperoxypropyl group, excluding 1e.
It seems, that the described low oxidizability of o-
methylisopropylarenes, e.g., o-cymene,15 can be explained
in a similar way. Also in this case, one of the hydrogens of
the methyl group can be transferred to the oxygen of the
alkoxy radical via a six-membered transition state. A
verification of this hypothesis requires, however, further
investigations. The explanation of this may be very important
for production of cresols by the cumene method.
inhibitor of free-radical oxidation processes. We have isolated
a small amount of 1-naphthol from the decomposition
product of hydroperoxide 1a in liquid phase by extraction
with NaOH.
Experimental Section
General. The experiments of thermal decomposition of
hydroperoxides were performed using a Varian 3300 gas
chromatograph conjugated with a SSQ 700 Mat Finnigan
mass spectrometer with EI ionization (70 eV). A solution of
hydroperoxides in CHCl3 at a concentration of 0.001 mg/
cm3 was introduced to the GC injector at 60 °C, and the
injector temperature was gradually raised with a rate of 25
°C/min up to 270 °C. Decomposition products were separated
on the DB5 capillary column (30 m, æ) 0.25 µ helium, 30
cm3/min). Melting points of synthesized compounds were
determined in capillary tubes on SMP 3 (Stuart Scientific)
apparatus. High-resolution mass spectra (HRMS) were
recorded on an AMD 604 spectrometer with EI ionization.
1H and 13C NMR spectra were recorded in CDCl3 on a Varian
Unity Inova-300 spectrometer using TMS as an internal
standard. IR spectra were recorded on a Zeiss Specord M
80 spectrometer. Kiesegel 60 (Merck 0.063-0.200 mm) was
used for column chromatography. TLC analyses were
performed using Merck’s plastic plates coated wit silica gel
60 F254. The computations were performed with MOPAC-7
program using AM1 (RHF for openshell systems) semiem-
pirical Hamiltonian. Geometries of all the species taken into
consideration were optimised, and heats of formation of the
molecules were calculated. The optimisation was performed
with the Eigenvector Following algorithm.16 The transition
states were obtained by the reaction path method and then
were optimised.
Conclusions
The unusual inhibition effect of hydroperoxide 1a on the
free-radical chain oxidation of isopropylarenes was eluci-
dated. The results described above strongly suggest that the
disadvantageous effect may consist of the following: (i)
termination of a free-radical chain as a result of the
recombination of radicals, which is necessary for the
formation of 2-(1-naphthyloxy)propene 5a and (ii) hydrolysis
of 5a to 1-naphthol. The explanation of the inhibition
mechanism may be essential, in case of starting the produc-
tion of 2-naphthol from technical 2IPN contaminated by
1IPN.
Other 1-aryl-1-methylethylhydroperoxides having the
hydrogen atom at the peri position to the substituent at the
1-position, e.g., 1-(1-anthryl)-1-methylethylhydroperoxide,
may also exhibit inhibition properties.
It was also demonstrated that GC-MS is a valuable
method for investigations of the thermal decomposition of
hydroperoxides. GC-MS allows observation of the forma-
tion of relatively unstable 2-(1-aryloxy)propenes as the
primary products of the thermal decomposition of some
1-aryl-1-methylethylhydroperoxides. 2-Aryloxypropenes are
formed as the main products from the corresponding hydro-
Materials. 1-(1-Naphthyl)-1-methylethylhydroperoxide
1a and 1-(2-naphthyl)-1-methylethylhydroperoxide 1b were
(15) Heinze, A.; Lauterbach, G. J. Prakt. Chem. 1987, 329, 439.
(16) Baker, J. J. Comput. Chem. 1986, 1, 385.
292
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Vol. 10, No. 2, 2006 / Organic Process Research & Development

Scheme 5. Proposed mechanisms of the transformation of 1-(1-naphthyl)-1-methylethyloxy radical to
2-(1-naphthyloxy)propene, where R ) 1-(1-naphthyl)-1-methylethyl
synthesized as previously described.17,18 Ethyl-3-chloro-2-
butenoate was synthesized as described by Holy.19
water solution of NaHCO3 (10%), and again water, and dried
with MgSO4. After evaporation of the ether, the pure product
was isolated from the residue by column chromatography
(benzene-ethyl acetate, 10:1) as a brown oil 6.74 g (67.9%).
After recrystallization from benzene, orange crystals were
obtained, mp 41-43 °C; (Found: C, 86.41; H, 6.70. C17H16O
requires C, 86.40; H, 6.82); νmax cm-1 3600; δH 9.39 (1 H,
s, Ar, 9-H), 8.38 (1 H, s, Ar, 10-H), 8.02-8.05 (1 H, m,
Ar), 7.87-7.95 (2 H, m, Ar), 7.48-7.50 (1 H, m, Ar), 7.42-
7.45 (3 H, m, Ar), 2.11 (1 H, s, OH), 1.89 [6 H, s, C(CH3)2];
δC 143.1 [C-C(CH3)2OH], 133.1, 131.1, 130.8, 129.1, 128.9,
128.3, 127.5, 127.1, 126.6, 125.6, 125.2, 124.2, 122.1 (Ar),
74.3 [C(CH3)2OH], 31.5 (CH3).
2-(2-Anthryl)-2-propanol and 2-(2-Anthryl)propene
(2d and 4d). The synthesis was carried out as described
above for 2-(1-anthryl)-2-propanol using magnesium turnings
(0.43 g, 18 mmol) and methyl iodide in diethyl ether (30
cm3) and 2-acetylanthracene (3.74 g, 17 mmol). The reaction
mixture was poured into a mixture of ice (8 g) and sulphuric
acid (3 cm3, 27%); the precipitated crystalline substance was
filtered off, and the pure product (2.61 g) was isolated by
crystallization from benzene. After evaporation of benzene
additional amounts of 2-(2-anthryl)-2-propanol (0.36 g) and
2-(2-anthryl)propene (0.48 g) were isolated from the residue
by column chromatography (benzene-ethyl acetate, 50:1).
The properties of the obtained compounds:
1-Acetyl- and 2-Acetylanthracene (3c and 3d). 1-Acetyl-
and 2-acetylanthracene were synthesized by acetylation of
anthracene (64 g, 0.36 mol) with acetyl chloride (34.6 g,
0.44 mol) in nitrobenzene (300 cm3) in the presence of AlCl3
(48 g, 0.36 mol) according to the procedure described by
Luttringhaus and Kacer.20 After purification of the crude
products by column chromatography (benzene-ethyl acetate,
10:1), the following pure products were obtained:
3c: yield 6.8 g (8.6%), mp 105-107 °C (lit.,20 103-105
°C); (Found: C, 87.15; H, 5.43. C16H12O requires C, 87.25;
H, 5.49); νmax cm-1 1680; δH 9.47 (1 H, s, Ar, 9-H), 8.43 (1
H, s, Ar, 10-H), 8.15 (1 H, d, J ) 8.4, Ar), 8.05-8.09 (1 H,
m, Ar), 7.97 (2 H, dd, J ) 6.3, 5.7, Ar), 7.47-7.52 (3 H, m,
Ar), 2.79 (3 H, s, CH3); δC 201.5 (COCH3), 134.8, 133.9,
133.0, 131.9, 131.5, 129.6, 129.2, 127.7, 127.6, 123.9, 126.1,
125.9, 125.8, 123.4 (Ar), 29.7 (CH3).
3d: yield 10.9 g (13.8%), mp 191-192 °C (lit.,20 183-
185 °C); (Found: C, 87.06; H, 5.42. C16H12O requires C,
87.25; H, 5.49); νmax cm-1 1680; δH 8.59 (1 H, s, Ar, 1-H or
9-H), 8.52 (1 H, s, Ar, 1-H or 9-H), 8.38 (1 H, s, Ar, 10-H),
7.94-8.02 (4 H, m, Ar), 7.46-7.55 (2 H, m, Ar), 2.73 (3
H, s, CH3); δC 197.9 (COCH3), 133.9, 133.2, 132.6, 131.9,
131.6, 130.3, 128.9, 128.4, 128.3, 128.1, 126.6, 126.2, 125.9,
122.6 (Ar), 26.5 (CH3).
2-(1-Anthryl)-2-propanol 2c. Methylmagnesium iodide
was synthesized in the usual manner21 from magnesium
turnings (1.02 g, 42 mmol) and methyl iodide (5.96 g, 42
mmol) in ethyl ether (30 cm3). The solution of methylmag-
nesium iodide was diluted with diethyl ether (20 cm3), and
pulverized 1-acethylanthracene (9.3 g, 42 mmol) was added.
The reaction mixture was stirred and refluxed for 2 h and
then poured into a mixture of ice (12 g) and sulphuric acid
(7 cm3, 27%). The mixture was extracted with diethyl ether,
and the organic layers were collected, washed with water, a
2d: yield 2.97 g (74.0%), mp 157-158 °C (after recrys-
tallization from benzene) (lit.,22 152-154 °C); (Found: C,
86.22; H, 6.68. C17H16O requires C, 86.40; H, 6.82); νmax
cm-1 3600; δH 8.38 (1 H, s, Ar, 9-H or 10-H), 8.37 (1 H, s,
Ar, 9-H or 10H), 8.04 (1 H, s, Ar, 1-H), 7.94-7.99 (3 H, m,
Ar), 7.57 (1 H, dd, J ) 9.0, 1.8, Ar), 7.42-7.46 (2 H, m,
Ar); 1.95 (1 H, s, OH), 1.69 [6 H, s, C(CH3)2]; δC 145.6
[C-C(CH3)2], 131.9, 131.6, 131.4, 130.7, 128.3, 128.13,
128.08, 126.4, 125.8, 125.3, 125.2, 123.7, 121.9 (Ar), 72.7
[C(CH3)2OH], 31.3(CH3).
4d: yield 0.30 g (7.5%), mp 161-162 °C (after recrys-
tallization from benzene) (lit.,22 150-152 °C); (Found: C,
93.16; H, 6.35. C17H14 requires C, 93.54; H, 6.46); νmax cm-1
1620 and 1460; δH 8.38 (1 H, s, Ar, 9-H or 10-H), 8.34 (1
H, s, Ar, 9-H or 10-H), 7.96-7.98 (2 H, m, Ar), 7.68 (1 H,
(17) Zawadiak, J.; Stec, Z.; Orlin´ska, B. Pol. J. Chem. 1998, 72, 1178.
(18) Kiritshenko, G. N.; Hannanov, T. M.; Kuzmin, E. K.; Borobeva, Zh. K.;
Rafikov, R. S. Neftekhimia 1971, 11, 862.
(19) Holy, A. Collect. Czech. Chem. Commun. 1974, 39, 3177.
(20) Luttringhaus, A.; Kacer, F. DE Patent 492 247, 1926.
(21) Vogel, A. I. Practical Organic Chemistry Including QualitatiVe Organic
Analysis, 3rd ed.; Longman, Green and Co.: New York, London, 1956; p
287.
(22) Hawkins, E. G. E. J. Chem. Soc. 1957, 3858.
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d, J ) 1.8, Ar), 7.65 (1 H, d, J ) 1.8, Ar), 7.42-7.45 (2 H,
m, Ar), 7.35-7.39 (1 H, m, Ar), 5.59 (1 H, s, CH2), 5.23 (1
H, dq, J ) 1.5, 1.5, CH2), 2.30 (3 H, s, CH3); δC 142.7
[C-C(CH3)2], 131.7, 131.6, 128.15, 128.10, 127.9, 126.6,
125.8, 125.4, 125.3, 125.1, 124.98, 124.90, 124.2, 123.7 (Ar),
113.2 (CH2), 21.7 (CH3).
of NaHCO3 (5%, 15 cm3); the water layer was extracted two
times with 1,2-dichloroethane (10 cm3), and the combined
organic layers were washed with a saturated solution of
(NH4)2SO4 (5 cm3) and water (5 cm3) and dried with MgSO4.
After evaporation of the solvent the pure hydroperoxide was
isolated from the residue by column chromatography using
CH2Cl2 as the eluent. The properties of the obtained
hydroperoxides:
1-(1-Anthryl)-1-methylethylhydroperoxide 1c: yield
0.73 g (29.1%), orange resin; (Found: C, 80.65; H, 6.67.
C17H16O2 requires C, 80.93; H, 6.39); νmax cm-1 3520; δH
9.41 (1 H, s, Ar, 9-H), 8.45 (1 H, s, Ar, 10-H), 7.94-8.09
(3 H, m, Ar), 7.46-7.51 (3 H, m, Ar), 7.36-7.38 (1 H, m,
Ar), 7.41 (1 H, s, OOH), 1.92 [6 H, s, C(CH3)2]; δC 139.2
[C-C(CH3)2OOH], 133.2, 132.1, 131.3, 129.8, 129.4, 129.2,
127.83, 127.82, 126.1, 125.8, 125.3, 124.9, 124.6 (Ar), 86.8
[C(CH3)2OOH], 27.2 (CH3).
1-(2-Anthryl)-1-methylethylhydroperoxide 1d: yield
1.25 g (49.6%), yellow resin; (Found: C, 82.15; H, 6.44.
C17H16O2 requires C, 80.93; H, 6.39); νmax cm-1 3520; δH
8.42 (1 H, s, Ar, 9-H or 10-H), 8.40 (1 H, s, Ar, 9-H or
10-H), 8.00 (1 H, s, Ar, 1-H), 7.98-8.04 (3 H, m, Ar), 7.62
(1 H, dd, J ) 2.1, 9.0, Ar), 7.41-7.48 (2 H, m, Ar), 7.40 (1
H, s, OOH), 1.74 [6 H, s, C(CH3)2]; δC 144.4 [C-C(CH3)2-
OOH], 141.2, 138.9, 131.9,131.6, 131.3, 130.9, 128.8, 128.1,
126.6, 125.9, 125.4, 124.4, 123.3 (Ar), 84.1 [C(CH3)2OOH],
25.8 (CH3).
1-(9-Anthryl)-1-methylethylhydroperoxide 1e: yield
0.54 g (21.1%), resin. (Found: C, 81.08; H, 6.46. C17H16O2
requires C, 80.93; H, 6.39); νmax cm-1 3520; δH 7.39-7.51
(5 H, m, Ar), 7.28-7.34 (2 H, m, Ar), 7.19-7.25 (2 H, m,
Ar), 5.78 (1 H, s, OOH), 2.13 [6 H, s, C(CH3)2]; δC 129.6
[C-C(CH3)2OOH], 128.6, 128.4, 127.5, 127.1, 127.0, 125.8,
125.3 (Ar), 85.7 [C(CH3)2OOH], 23.5 (CH3).
2-(9-Anthryl)-2-propanol and 2-(9-Anthryl)-2-propene
(2e and 4e). To a stirred suspension of magnesium turnings
(1.53 g, 63 mmol) in dibutyl ether (120 cm3) was added
9-bromoanthracene (15.2 g, 59 mmol). The reaction mixture
was heated under argon to 135-141 °C for 1 h. When the
temperature of the reaction mixture reached 130 °C, an iodine
crystal and methyl iodide (0.2 cm3) were added to start the
reaction. After the reaction mixture cooled to about 7 °C, a
solution of dry acetone (6.7 g 115 mmol) in dibutyl ether
(14 cm3) was added dropwise, the stirring was continued at
room temperature for 1.5 h, and the reaction mixture was
poured into a mixture of ice (280 g) and hydrochloric acid
(63 cm3, 10%). The precipitated crystalline substance was
filtered off, the ethereal layer was separated, and the water
layer was extracted with dibutyl ether. The combined ethereal
layers were washed with a water solution of NaHCO3 (10%)
and then with water, and dried over MgSO4, and the solvent
was evaporated. The residue was combined with the crystal-
line substance, the mixture was dissolved in benzene (30
cm3), and the solved part of the mixture was separated by
column chromatography (benzene-ethyl acetate, 50:1, 700
cm3 of silica gel) to get 2-(9-anthryl)-2-propanol and 2-(9-
anthryl)propene with the following properties:
2e: yield 2.60 g (18.7%), mp 132-134 °C (orange crystals
after recrystallization from benzene) (lit.,23 138-140 °C);
(Found: C, 86.02; H, 6.51. C17H16O requires C, 86.40; H,
6.82); νmax cm-1 3600; δH 8.73-8.78 (2 H, m, Ar), 8.29 (1
H, s, Ar, 10-H), 7.91-7.94 (2 H, m, Ar), 7.31-7.40 (4 H,
m, Ar), 2.14 [7 H, s, OH, C(CH3)2]; δC 141.0 [C-C(CH3)2],
132.1, 129.0, 128.9, 128.2, 127.0, 124.2,123.8 (Ar), 76.8
[C(CH3)2OH], 33.5 (CH3).
4e: yield 1.17 g (8.4%), resin; (Found: C, 92.67; H, 6.78.
C17H14 requires C, 93.54; H, 6.46); νmax cm-1 1640 and 1620;
δH 8.35 (1 H, s, Ar, 10-H), 8.13-8.17 (2 H, m, Ar), 7.94-
7.99 (2 H, m, Ar), 7.41-7.47 (4 H, m, Ar), 5.74 (1 H, s,
CH2), 5.13 (1 H, s, CH2), 2.25 (3 H, s, CH3); δC 142.9
[C-C(CH3)2], 138.9, 131.5, 128.5, 126.2, 125.7, 125.3, 125.1
(Ar), 117.9 (CH2), 25.5 (CH3).
Methyl 3-(1-Naphthyloxy)-2-butenoate. To stirred metha-
nol (8 cm3) was slowly added sodium (0.46 g, 20 mmol)
under nitrogen. After dissolution of sodium, 1-naphthol (2.88
g, 20 mmol) was added, the reaction mixture was refluxed
for 1 h, and then ethyl 3-chloro-2-butenoate (1.48 g, 10
mmol) was added; the reaction mixture was refluxed for 7
h. The reaction mixture was poured on ice, the product was
extracted with diethyl ether, and the ethereal solution was
dried with MgSO4. After evaporation of the solvent the pure
methyl 3-(1-naphthyloxy)-2-butenoate (1.38 g, 57%) was
isolated from the residue by column chromatography using
a mixture of toluene and ethyl acetate, 5:1 (v/v) as the eluent.
Oxidation of 2-Anthryl-2-propanols to 1-Anthryl-1-
methylethylhydroperoxides (General Procedure). To the
intensively stirred mixture of 2-anthryl-2-propanol (2.36 g,
10 mmol) in 1,2-dichloroethane (20 cm3) was added at 50
°C a solution of H2SO4 (96%, 0.09 cm3, 0.16 g, 1.6 mmol)
in H2O2 (67%, 4.8 cm3, 4.06 g, 80 mmol). The reaction
progress was controlled by the TLC method using the CH2-
Cl2/acetone, 35:1 (v/v) mixture as the eluent and a saturated
solution of NaI in acetic acid for developing the hydroper-
oxide spots. The reaction times for 1-(1-anthryl)-, 1-(2-
anthryl)-, and 1-(9-anthryl)-1-methylethylhydroperoxide were
3.5, 3, and 2.5 h, respectively. The reaction mixture was
cooled to room temperature and washed with a water solution
ν
max cm-1 1710 and 1140; δH 7.10-7.93 (7 H, m, Ar), 4.81
(1 H, s, CH), 3.56 (3 H, s, OCH3), 2.65 (3 H, s, CH3); δC
172.8 (CHO), 168.0 (CdO), 149.1, 134.9, 128.0, 126.7,
126.5, 125.9, 125.6, 121.4, 117.8 (Ar), 95.9 (CH), 50.8
(OCH3), 18.2 (CH3).
3-(1-Naphthyloxy)-2-butenoic Acid. To a solution of
KOH in ethanol (10%, 28 cm3) was added methyl 3-(1-
naphthyloxy)-2-butenoate (1.38 g, 5.7 mmol), and the
mixture was refluxed for 4 h. After evaporation of the solvent
the residue was dissolved in water (3 cm3), made slightly
acidic with H2SO4 (10%), and extracted three times with
diethyl ether (6 cm3). The ethereal solution was dried with
(23) Becker, H. D.; Langer, V. J. Org. Chem. 1993, 58, 4703.
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MgSO4, the solvent was evaporated, and the crystalline
residue was recrystallized from benzene to get pure product
(1.01 g, 78%), mp 155-157 °C; νmax cm-1 3200-2800,
1680, 1618, and 1155; δH 7.12-7.94 (7 H, m, Ar), 4.79 (1
H, s, CH), 2.62 (3 H, s, CH3); δC 174.8 (CHO), 173.0 (CO),
149.0, 135.0, 128.1, 126.7, 126.6, 126.1, 125.6, 121.4, 117.9
(Ar), 95.7 (CH), 18.6 (CH3); HRMS (EI): Found: 228.0782;
C14H13O3 requires: 228.0786.
extracted with an aqueous solution of NaOH (15%). The
inorganic layer was neutralized with diluted HCl and
extracted with diethyl ether. The etheral solution was dried
with MgSO4, and ether was evaporated; 0.016 g of acidic
substance was obtained. 1-Naphthol (0.008 g) was isolated
from this mixture by preparative TLC (CH2Cl2-acetone, 20:
1).
Column chromatography (hexane-acetone, 20:1) was
used to isolate 2-aryloxypropene 5a from the decomposition
product after extraction with NaOH. Unfortunately, aryloxy-
propene 5a underwent subsequence reactions, e.g. hydrolysis
to 1-naphthol. The additional amount of 1-naphthol was
obtained (0.0139 g). The obtained 1-naphthol (0.0147 g) was
2-(1-Naphthyloxy)propene 5a. A glass test tube with a
capillary neck containing 3-(1-naphthyloxy)-2-butenoic acid
(1.01 g, 4.45 mmol) was heated at 180 °C for 2 h. The
product (0.39 g, 48%) was isolated from the residue by
column chromatography using toluene as the eluent; νmax
cm-1 1635, 1255, and 1160; δH 7.06-8.08 (7 H, m, Ar),
4.16 (1 H, s, CH2), 3.88 (1 H, s, CH2), 2.13 (3 H, s, CH3);
δC 159.7 (CHO), 150.6, 134.7, 128.2, 127.7, 126.1, 126.0,
125.6, 122.7, 122.4, 115.4 (Ar), 89.7 (CH2), 19.9 (CH3);
HRMS (EI): Found: 184.0881; C13H12O requires: 184.0888.
Thermal Decomposition of 1-(1-Naphthyl)-1-methyl-
ethylhydroperoxide 1a in Liquid Phase. The hydroperoxide
1a was thermally decomposed in closed glass test tube. Each
test tube was filled with about 1 cm3 of a solution of 1a in
cumene (5 cm3; 5 mol/dm3; 2.55 mmol), flushed with argon,
closed and immersed in an oil bath at 140 °C for 15 h.
Hydroperoxide 1a was completely decomposed. The product
contained a large amount of tarry substances and, apart from
that, alcohol 2a and ketone 3a, which were obtained with
44% and 17% selectivity, respectively (HPLC analysis24).
The product was diluted with diethyl ether (40 cm3) and
1
characterized by H NMR, IR and MS.
The small amount of aryloxypropene 5a (0.0215 g) was
isolated only by preparative TLC (benzene as eluent). Its
1
structure was confirmed by H NMR and IR.
Thermal decomposition of 1-(1-naphthyl)-1-methyleth-
ylhydroperoxide 1b was also carried out under the same
conditions (140 °C, 0.5 mol/dm3 in cumene, 15 h). The
obtained product contained only alcohol 2b and ketone 3b
(76 and 24% selectivity, respectively).
Acknowledgment
Financial support of the Polish State Committee for
Scientific Research (Grant No. 7 TO9B 082 21) is gratefully
acknowledged.
Received for review December 5, 2005.
OP0502351
(24) Zawadiak, J.; Orlin´ska, B.; Stec, Z. Fresenius’ J. Anal. Chem. 2000, 367,
502.
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