Synthesis of 4,8-dibenzoyl-1,5-dihydroxynaphthalene and of some derivatives thereof

Article abstract of DOI:10.1023/A:1012477718250

Demethylation of 4,8-dibenzoyl-1,5-dimethoxynaphthalene was carried out to afford the corresponding bis-peri-hydroxydiketone and its derivatives. The acylation and alkylation was performed with one among these derivatives, 6-benzoyl-2-phenylnaphtho[bc]fur

Full text of DOI:10.1023/A:1012477718250

Russian Journal of Organic Chemistry, Vol. 37, No. 4, 2001, pp. 513 516. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 4, 2001,
pp. 548 551.
Original Russian Text Copyright
2001 by Mezheritskii, Tyurin, Minyaeva.
Synthesis of 4,8-Dibenzoyl-1,5-dihydroxynaphthalene
and of Some Derivatives Thereof*
V. V. Mezheritskii, R. V. Tyurin, and L. G. Minyaeva
Research Institute of Physical and Organic Chemistry of Rostov State University, Rostov-on-Don, 344090 Russia
Received October 14, 1998
Abstract Demethylation of 4,8-dibenzoyl-1,5-dimethoxynaphthalene was carried out to afford the cor-
responding bis-peri-hydroxydiketone and its derivatives. The acylation and alkylation was performed with
one among these derivatives, 6-benzoyl-2-phenylnaphtho[bc]furan-5-one.
peri-Hydroxysubstituted naphthaldehydes and
naphthyl ketones are known to be potential precursors
of the peri-annealed heterocycles [1]. In the same way
bis-peri-hydroxynaphthoyl compounds can become
key initial substances in the synthesis of various
representatives from the virtually unknown series of
bis-peri-anneled heterocyclic systems.
As a result of the reaction forms a mixture of di-
methylation products II IV in a ratio depending on
the temperature of the process.
At room temperature the main product is the
partially demethylated hydroxymethoxydiketone II
whereas at 90 C prevails exhaustive demethylation
yielding methylenequinone IV. Dihydroxydiketone
III is present in traces at both temperature modes. Its
presence is qualitatively indicated by a characteristic
blot at the start during chromatography of the reaction
mixture on the thin layer of alumina. Methylene-
quinone IV arises due to acid-catalyzed dehydration
of the dihydroxydiketone III. The reversed conver-
sion IV III is achieved by treating methylene-
quinone IV with perchloric acid in acetic acid solu-
tion with subsequent addition of water. Here the
precursor of dihydroxyketone III is the corresponding
naphtho[bc]furylium salt V that can be isolated in
crystalline state and that is quickly hydrolyzed with
air moisture at standing in air.
We lately obtained 4,8-dihydroxy-1,5-diformyl-
naphthalene [2]. This study is aimed to look for new
approaches in the synthesis of the first bis-peri-
hydroxynaphthyldiketones and their simple deriva-
tives.
One of possible ways to prepare the desired
compounds can be a dealkylation of the appropriate
bis-peri-methoxydiketones. To this end the formerly
reported [3] 1,5-dibenzoyl-4,8-dimethoxynaphthalene
(I) was treated with anhydrous aluminum chloride at
heating in tetrachloroethane.
(2)
(1)
The attempt to prepare and isolate crystalline
5-ethoxy- (VI) or 5-acetoxy- (VIII) substituted salts
of the naphtho[b,c]furylium by reacting quinone VI
with triethyl orthoformate or acetic anhydride respec-
tively in the presence of boron trifluoride etherate or
acetate did not give the desired result. On diluting the
reaction mixtures with ether the expected salts did not
precipitate but their formation is evidenced by the
*
The study was carried out under financial support of the Rus-
sian Foundation for Basic Research (grant no. 96-03-332145a).
1070-4280/01/3704-0513$25.00 2001 MAIK Nauka/Interperiodica

514
MEZHERITSKII et al.
Scheme.
hydrolysis products of the reaction mixtures. The
reaction of quinone IV with triethyl orthoformate
(see scheme) apparently gives rise to o-ethylated VI
In all experiments the hydrolysis products were
separated by column chromatography on alumina,
eluent chloroform. The weighted ratios of the
separated products are listed in EXPERIMENTAL.
and O-protonated
V cations with considerable
prevalence of the former. The reaction with water of
cation VI takes a single route consisting in opening of
the heterocycle to afford diketone VII, whereas the
hydrolysis of cation V occurs according to Scheme 2
yielding a mixture of hydroxydiketone III and
quinone IV.
EXPERIMENTAL
IR spectra of compounds obtained were recorded
on spectrophotometer Specord IR-71 from mulls in
mineral oil. 1H NMR spectra were registered on
spectrometer Varian Unity-300, solvent CDCl3,
internal reference HMDS. The purity of compounds
obtained was checked by TLC on alumina, eluent
chloroform.
The result of hydrolysis of acetoxycation VIII
depends on reaction conditions. For instance, dilution
with water of the salt VIII solution in the acetic
anhydride affords a mixture of hydroxyacetoxydi-
ketone IX and quinone IV with prevalence of the
former. In other words the attack of water molecules
playing the role of a nucleophile is directed to the
carbon atoms in position 2 of the heteroring of
naphtho[bc]furylium cation VIII or to the carbon of
the ester group in the cation.
Spectral characteristics of compounds synthesized
are presented in Table 1, elemental analyses in
Table 2.
Demethylation of 1,5-dibenzoyl-4,8-dimethoxy-
naphthalene (I). (a) Into a heated to 30 35 C
dispersion of 1.2 g (0.003 mol) of 1,5-dibenzoyl-4,8-
dimethoxynaphthalene (I) in 30 ml of tetrachloro-
ethane was added by portions 2 g of anhydrous
aluminum chloride. The mixture was heated under
reflux on a water bath for 40 min, cooled, and poured
into ice water. The solvent was removed by steam
distillation. The yellow solid was twice crystallized
from dimethylformamide to obtain 0.65 g (85%) of
6-benzoyl-2-phenyloxynaphtho[bc]furan-5-one (IV),
mp 245 C.
The hydrolysis of the reaction mixture containing
cation VIII preliminary diluted with ethyl ether takes
place at the phase boundary between the ether and
water layer and results in a mixture of 2-ethoxy-
naphtho[bc]furan (X) (main product) and quinone IV.
We presume that the formation of the ethoxy deriv-
ative X occurs by reaction of acetoxycation VIII with
ethanol contained in the ethyl ether for the same
compound was obtained by hydrolysis of the reaction
mixture with ethanol.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 4 2001

SYNTHESIS OF 4,8-DIBENZOYL-1,5-DIHYDROXYNAPHTHALENE
Filtrate was poured into water, the precipitate was Table 1. Spectral characteristics of compounds II X
515
collected and treated with 5% solution of NaOH. The
alkaline solution was acidified with diluted (1: 1) HCl
to obtain 30 mg (3%) of colorless 4,8-dibenzoyl-1,5-
dihydroxynaphthalene (III), mp 275 C (from ethanol).
Compd. IR spectrum,
1H NMR spectrum,
, ppm
1
no.
, cm
II
3220, 1647,
1607
The residue was crystallized from ethanol to obtain
115 mg (10%) of 4,8-dibenzoyl-1-hydroxy-5-methoxy-
naphthalene (II), mp 261 C.
III
IV
3498, 1656, 4.05 s (éH, OCH3); 7.2 7.85 m
1635, 1607 (14H, arom.); 8.65 s (1H, OH)
1660, 1633, 7.36 8.1
1580, 1554
m (14 H, arom.)
(b) Into a heated to 30 35 C dispersion of 1.75 g
(0.0045 mol) of 1,5-dibenzoyl-4,8-dimethoxynaphthal-
ene (I) in 35 ml of tetrachloroethane was added by
portions 3 g of anhydrous aluminum chloride. The
mixture was stirred for 1 h at room temperature, then
the reaction mixture was poured into ice water. The
solvent was removed by steam distillation. The solid
was twice crystallized from ethanol to obtain 1.3 g
(77%) of compound II, mp 261 C.
VII
3180, 1660 0.97 t (3H, CH3CH2); 3.8 4 m
1647, 1593 (2H, CH3CH2); 6.7 8.1
1580 (14 H, arom.); 8.7 s (1H, OH)
m
IX
X
3193, 1780, 1.9 s (éH, CH3CO); 6.9 7.9 m
1673, 1647, (14H, arom.); 9.0 s (1H, OH)
1593
1767, 1660, 1.25 t (3H, CH3CH2); 2 m
1633, 1607, (3H, CH3CO); 3.25 3.6 s (2H,
1595
CH3CH2); 6.8 7.9
arom.)
m (14H,
Filtrate was poured into water, the precipitate was
collected and treated with 5% solution of NaOH. The
alkaline solution was acidified with diluted (1: 1) HCl
to obtain 52 mg (4%) of colorless 4,8-dibenzoyl-1,5-
dihydroxynaphthalene (III), mp 275 C (from ethanol).
Table 2. Elemental analyses of compounds II X
Compd. Found, %
no.
Calculated, %
The residue was crystallized from dimethylform-
amide to obtain 150 mg (10%) of compound IV, mp
245 C.
Formula
C
H
C
H
6-Benzoyl-5-hydroxy-2-phenylnaphtho[bc]furyl-
ium perchlorate (V). To a dispersion of 50 mg
(0.0014 mol) of quinone IV in 1 ml of acetic acid was
added dropwise 0.14 ml of 72% perchloric acid, and
the mixture was boiled for 5 7 min. On cooling
separated a red precipitate that was filtered off,
washed with ether, and dried. We obtained 60 mg
(96%) of compound V, mp 235 C.
II
III
IV
VII
IX
X
78.49 4.65
78.35 4.28
82.40 4.15
78.81 5.21
76.26 4.45
76.59 5.28
C25H18O4
C24H16O4
C24H14O3
C26H20O4
C26H18O5
C28H22O5
78.53
78.26
82.29
78.79
76.10
76.71
4.71
4.35
4.00
5.05
4.39
5.02
off. We obtained 60 mg (59%) of colorless compound
Hydrolysis of perchlorate V. To a dispersion of
43 mg (0.0001 mol) of perchlorate V in 1 ml of
acetone was added dropwise water (3 4 ml). The
yellow precipitate was filtered off, washed with
water, dried, treated with 5% solution of NaOH,
acidified with diluted (1: 1) HCl. We obtained 7 mg
of compound III. The residue was crystallized
from dimethylformamide to afford 24 mg (69%) of
quinone IV.
VII, mp 267 C (from ethanol).
The ethanol solution was diluted with water,
the separated precipitate was filtered off, dried,
and subjected to chromatography on a column
packed with alumina (eluent chloroform). We ob-
tained 12 mg (13%) of quinone IV and 7 mg (7%) of
compound III.
5-Acetoxy-6-benzoyl-2-phenyl-2H-2-ethoxy-
naphtho[bc]furan (X). To a hot dispersion of 0.18 g
(0.0005 mol) of quinone IV in 2 ml of acetic
anhydride was added 0.15 ml (0.001 mol) of boron
trifluoride etherate, the red solution was heated for
2 3 min, cooled, diluted with ether, and poured into
water. The thick viscous substance formed was twice
2,6-Dibenzoyl-1-hydroxy-5-ethoxynaphthalene
(VII). A dispersion of 90 mg (0.00025 mol) of
quinone IV in 2 ml of triethyl orthoformate and
0.2 ml of boron trifluoride acetate was stirred with a
magnetic stirrer for 2 h, then the mixture was diluted
with water, and the precipitate formed was filtered
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 4 2001

516
MEZHERITSKII et al.
crystallized from ethanol to obtain 98 mg (80%) of
obtained 78 mg (74%) of compound IX, mp 263 C
(from alcohol).
colorless crystals of compound X, mp 136 C.
The ethanol solution was diluted with water, the
separated precipitate was filtered off, dried, and
subjected to chromatography on a column packed
with alumina (eluent chloroform). We obtained 10 mg
(11%) of quinone IV.
The ethanol solution was diluted with water,
the separated precipitate was filtered off, dried,
and subjected to chromatography on a column
packed with alumina (eluent chloroform). We ob-
tained 24 mg (13%) of quinone IV and 10 mg (5%)
of compound III.
REFERENCES
5-Acetoxy-2,6-dibenzoyl-1-hydroxynaphthalene
(IX). To a hot dispersion of 90 mg (0.00025 mol) of
quinone IV in 1.5 ml of acetic anhydride was added
0.06 ml (0.0005 mol) of boron trifluoride etherate.
The mixture was maintained at the room temperature
for 20 30 min, and then diluted with water. We
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Heterocyclic Chem., 1991, vol. 51, pp. 1 103.
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3. Fierz-David, H.E. and Jaceard, G., Helv. Chim. Acta,
1928, vol. 11, p. 1042.
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