Building up of a peri-hydroxynaphthoyl fragment on the core of 2H-naphtho[1,8-bc] furan

Article abstract of DOI:10.1007/s11178-005-0148-4

The reaction of 2-aryl-5-acetoxy-4,8-di-tert-butyl-2H-naphtho[1,8-bc]furan with dichloromethyl ethyl ether in the presence of aluminum chloride gave rise to 6-formyl derivatives of the title heterocyclic system, and at the use of aliphatic acids anhydrides in the presence of perchloric acid 6-acyl derivatives were obtained. The target products with a peri-hydroxycarbonyl group were obtained by the ester group elimination. 2005 Pleiades Publishing, Inc.

Full text of DOI:10.1007/s11178-005-0148-4

Russian Journal of Organic Chemistry, Vol. 41, No. 2, 2005, pp. 227-232. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005,
pp. 237-242.
Original Russian Text Copyright Ó 2005 by Tyurin, Antonov, Minyaeva, Mezheritskii.
Building up of a peri-Hydroxynaphthoyl Fragment on the Core
of 2H-Naphtho[1,8-bc]furan
R.V. Tyurin, A.N. Antonov, L.G. Minyaeva, and V.V. Mezheritskii
Research Institute of Physical and Organic Chemistry, Rostov State University, Rostov-on-Don, 344090 Russia
e-mail: mezher@ipoc.rsu.ru
Receved June 29, 2004
Abstract—The reaction of 2-aryl-5-acetoxy-4,8-di-tert-butyl-2H-naphtho[1,8-bc]furan with dichloromethyl ethyl
ether in the presence of aluminum chloride gave rise to 6-formyl derivatives of the title heterocyclic system, and at
the use of aliphatic acids anhydrides in the presence of perchloric acid 6-acyl derivatives were obtained. The
target products with a peri-hydroxycarbonyl group were obtained by the ester group elimination.
In our previous studies we started from 1-acyloxy-5-
methoxynaphthalenes in preparation of the peri-hydroxy-
naphthoyl moiety [7]. In the present work taking into
account that the positions 4 and 8 (ortho-positions with
respect to oxygen atoms) were blocked by tert-butyl
substituents we hoped to construct the target peri-
hydroxycarbonyl fragment omitting the stages of acylation
and deacylation of the 5-hydroxy group. However both
the formylation by Rieche reaction [8] and acylation with
aromatic acyl chlorides by Friedel-Crafts reaction in
the presence of the aluminum chloride [9] resulted in
intractable products mixtures. We failed to isolate from
these reaction mixtures individual substances in amounts
sufficient for performing further synthetic attempts.
Naphthalene derivatives containing in contiguous peri-
positions a hydroxy and a carbonyl functions are potential
precursors in the synthesis of peri-annelated heterocycles
[1]. When therewith the two other peri-positions of the
naphthalene are closed into a ring, the newly constructed
peri-hydroxycarbonyl moiety may underlie the building
up of the second peri-annelated heterocycle. Hence we
state one among the strategies of building up bis-peri-
annelated heterocyclic systems. Nowadays only single
examples of bis-peri-annelated heterocycles were
described [2–5] whose synthesis and investigation of some
reactions were of accidental character, and the studies
in this field as a whole could not be regarded as
systematic. At the same time the bis-peri-annelated
heterocyclic systems should possess characteristics of
interest both from theoretical (e.g., study of the aromaticity
problems) and practical viewpoint. The highly annelated
systems are known to be prone to radiation processes
whose study in the last few years is among the most
important problems in creating working medium in memory
devices.
Better objects of Rieche reaction proved to be O-acetyl
derivatives II prepared by boiling the corresponding
naphtholes I in acetic anhydride in the presence of sodium
acetate. For instance, bringing into the reaction 2-tolyl
derivative of 5-acetoxynaphtho[1,8-bc]furan (IIa) we
obtained in a high yield formylation product IIIa.
Interestingly, under the formylation conditions a cleavage
of the ester group occurred and thus we isolated at once
from the reaction mixture the desired peri-hydroxyformyl
derivative IIIa (Scheme 1).
We believe that for designing bis-peri-annelated
heterocycles of the naphthalene series 2-aryl-4,8-di-tert-
butyl-5-hydroxy-2H-naphtho[1,8-bc]furans (I) may serve
as useful synthones.We reported on the synthesis of the
latter in [6].
On replacing in the 2-aryl substituent the para-methyl
group by a more electron-donor para-methoxy group a
bisformylation occurred into the position 6 of the
naphthofuran ring and into position 3 of the aryl
substituent. In this way from 2-(4-methoxyphenyl)
derivative IIb we obtained dialdehyde IIIb. The
formylation of 2-(3,4-dimethoxyphenyl)-2H-naphtho[1,8-
bc]furan (IIc) gave rise to a mixture of monoformyl IIIc
Actually, the electron-donor effect of the oxygen of
the furane ring alongside the presence of a hydroxy group
in position 5 and a tert-butyl substituents in positions 4
and 8 open up a possibility to introduce a carbonyl group
just in the 6 position, i.e., to build up a peri-hydroxy-
carbonyl fragment.
1070-4280/05/4102-0227Ó2005 Pleiades Publishing, Inc.

228
TYURIN et al.
Scheme 1.
C
6ꢁ
C
C
P
6ꢁ
6ꢁ
P
P
Wꢀ7ˆ
Wꢀ7ˆ
Wꢀ7ˆ
@‡P8C8y
6y8y
ꢂS8Pꢃ P
6pPIh
7ˆꢀW
7ˆꢀW
7ˆꢀW
P
S
PC
,D ,F
PC
C
P
P
,,D ,,F
,,,D ,,,F
ꢂS8Pꢃ P
C8yP
ꢂS8Pꢃ P
C8yP
C
C
6ꢁ
8 C ꢂPHrꢃ ꢀ"ꢄ#
6ꢁ
P
P
P
Wꢀ7ˆ
Wꢀ7ˆ
Wꢀ7ˆ
HrPIh
HrPC
b‚d
9E
7ˆꢀW
7ˆꢀW
7ˆꢀW
PC
P
P
P
S
Hr
P
Hr
P
S
P
9Dꢀꢁ9E
9,
,9D ,9F
B, Ar = 4-MeC6H4 (a), 4-MeOC6H4 (b), 3,4-(MeO)2C6H3 (c); II, IV, R = Me, Ar = 4-MeC6H4 (a), 4-MeOC6H4 (b),
3,4-(MeO)2C6H3 (c); R = Et,Ar = 4-MeOC6H4 (d); III,Ar = 4-MeC6H4 (a), 3-CHO-4-MeOC6H3 (b), 3,4-(MeO)2C6H3 (c),
2-CHO-3,4-(MeO)2C6H2 (d); V,Ar = 4-MeOC6H4 (a), 3,4-(MeO)2C6H3 (b).
and bisformyl IIId derivatives from which we succeeded
to isolate by chromatography a certain amount of individual
compound IIIc. The mixture of compounds IIIc and IIId
was characterized only by spectral methods.
not isolate any individual substances. Only in reaction of
6-acetoxynaphtho[1,8-bc]furan (IIb) with benzoyl
chloride in the presence of aluminum chloride we
separated in a 12% yield the corresponding peri-acetoxy-
ketone IVe (Scheme 2).
The acylation of 6-acyloxynaphtho[1,8-bc]furans II
with aliphatic acyl chlorides (acetyl and propionyl
chlorides) catalyzed by perchloric acid afforded the
corresponding peri-acyloxyketones IV. The acetylation
of propionyloxy derivative IId under these conditions
occurred with transesterification giving peri-acetoxy-
ketone IVa. It is of interest that peri-acyloxyketones IV
can be obtained directly from 5-hydroxynaphtho[1,8-bc]-
furans I and aliphatic acyl chlorides in the presence of
perchloric acid. In the latter reaction the C-acylation is
preceded by the O-acylation of the naphthol hydroxy
group.
The deacylation of obtained peri-acyloxyketones IV
effected by sodium methylate afforded the target peri-
hydroxyketones V in good yields. The possibility of peri-
hydroxyketones conversion into a methylenequinoid form
Scheme 2.
+
& + 20Hꢀꢁ
2
Wꢀ%X
3K&2&O
$O&O
,,E
We practically failed to prepare arylketones (IV, R =
Ar) by C-aroylation of 6-acetoxynaphtho[1,8-bc]furans
II with aromatic acids in polyphosphric acid or with aroyl
chlorides in the presence of aluminum chloride. In most
cases intractable mixtures were obtained, and we could
%XꢀW
2
0H
3K
2
2
,9H
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

BUILDING UP OF A peri-HYDROXYNAPHTHOYL FRAGMENT
229
VI was shown by an example of treating compound Vb
with potassium ferrocyanide.
The composition and structure of all compounds
synthesized were proved by elemental analysis and
spectral methods. The most of spectral characteristics
given in the EXPERIMENTAL do not require further
comments.
2
&
2
&
&
&
&
&
1
IR and H NMR spectra of dialdehyde IIIb require
&
&
some elucidation. Two aldehyde groups of its molecule
appear in the IR spectrum as two absorption bands of
C=O bonds stretching vibrations at 1647 (formyl group
&
&
&
2
&
&
2
&
–1
involved into a hydrogen bond) and 1687 cm , and in the
&
&
1H NMR spectrum as two one-proton singlets at 9.5 and
10.5 ppm. The signal at 9.5 ppm obviously corresponds
to the formyl group attached to the naphthalene ring. Its
more upfield position is due to the intramolecular hydrogen
bond with the proton of the peri-hydroxy group [10]. The
&
&
&
&
1
latter is seen in the H NMR spectrum as a one-proton
Crystal structure of 6-acetyl-4,8-di-tert-butyl-5-hydroxy-2-(4-
methoxyphenyl)-2H-naphtho[1,8-bc]furan (Va).
singlet at 12.8 ppm that disappears on deuteroexchange.
The downfield signal at 10.5 ppm is well consistent with
the proton chemical shifts in the ortho-substituted
benzaldehydes [11].
naphthalene bonds but not touching the aromatic skeleton.
In the peri-hydroxynaphthoyl derivative B the formation
of the intramolecular hydrogen bond between the carbonyl
oxygen and the hydroxy group proton is less favorable
that the attractive interaction between the hydroxy group
oxygen and the carbonyl carbon, and just the latter exists
in the crystalline structure.
The structure of peri-hydroxyketone (Va) was
subjected to X-ray diffraction analysis (see figure).
According to the X-ray diffraction data in the nearly
planar molecule (the largest deviations from the plane do
not exceed 6°) exists an efficient intramolecular hydrogen
bond between the hydroxy and the carbonyl groups
present in the peri-position. For instance, the dihedral
angle C13O15O24C10 (here and hereinafter the
This fact may be understood considering that the
involvement of the peri-carbons into the seven-membered
ring arising at formation of the intramolecular hydrogen
bond and the proper formation of this ring leading to
repulsion of the nucleophilic and electrophilic substituent
requires considerable distortion of the bond angles in the
molecule. Apparently the energy gain at the intra-
molecular hydrogen bond formation is not sufficient to
provide for the losses at the deformation of a stable
aromatic system and at the counteraction against the
attractive interaction (Scheme 3).
crystallographic notaion of atoms is given) is equal to
°
...
7.68°, the distance O–H O is 2.493 A, the OHO angle
is 170.7°. These parameters unambiguously show the
presence of an intramolecular hydrogen bond. The bond
angles in the naphthalene skeleton deviate significantly
from the classic values (120°). The largest distortions
are observed at the bridging carbon atoms: angles
C4C12C7 and C1C11C10 equal respectively to109.81° and
132.54°. These distortions result in alterations in the
distances between the atoms located in the peri-position
The known example of a compound with a hydrogen
bond in a seven-membered ring between the substituents
in positions 1 and 8 of naphthalene [12] whose geometry
correlates well with that of our substance is the zwitter-
ionic form of amino acid D. However it is stabilized in
the crystal by formation of an intermolecular hydrogen
bond between its carboxylate group and a carboxy group
of amino acid C resulting in dimers in the molecular
packing.
°
that in contrast to an ideal value (2.45 A) become equal
°
to 2.651 (C1C10) and 2.285 (C4C7) A. The above deform-
ations of the naphthalene skeleton are evidently due to
the presence of the furan ring.
The published X-ray diffraction data [12–14] on the
fine structure of nucleophile-substituted peri-naphthoyl
derivatives A, among them those with Nu = OH, clearly
...
demonstrate the attractive interaction Nu C=O resulting
In our case the additional factor stabilizing the seven-
membered ring with an intramolecular hydrogen bond
in the deformation of the bond angles of the exocyclic
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

230
TYURIN et al.
with U(H) = 1.2U(C) [U(C) is the equivalent thermal
Scheme 3.
10H
factor of the carbon linked to the corresponding hydrogen
atom]. The final values of the unreliability factors
(301 refined parameter) accounting for 5413 reflections
were calculated till R1 = 0.0639 [calculated along Fhkl
for 2329 reflections with I > 2s(I)], wR2 0.1202, GOOF
0.982. The residual electron density from the difference
2
2
10H
+
2
1X
$
%
°
Fourier series was 0.215 and –0.213 A-3. The main geo-
2 +
2
0H
0H
2 + 0H
1
2
metrical parameters from the X-ray data are as follows:
1
0H
°
interatomic distances (A), C1–C11 (1.467), C10–C11
(1.429), C4–C12 (1.404), C7–C12(1.388), C1–C13 (1.468),
C10–O24 (1.359), C13–O15 (1.237), O15–O24 (1.498),
C4–O5 (1.368), O5–C6 (1.483), C6 –C7 (1.515); bond
angles (deg), C4C12C7(109.81), C1C11C10 (132.54),
C11C1C13 (126.12), C11C10O24 (121.64), C4O5C6 (108.81),
O5C6C7 (103.47), C6C7C12 (107.29), C13O5H (111.18),
C10O24H (170.70), C1C13O15 (123.14), C4C12C11 (125.02).
&
'
Nu = OMe, NMe2, OH.
consists apparently in the forced deformation of the bond
angles of the naphthalene skeleton because of the
annelated furan ring. This observation once more supports
our previous [15] assumptions that the formation of a
seven-membered ring on the naphthalene peri-positions
is facilitated by the presence in the molecule of a peri-
annelated five-membered ring.
5-Acetoxy-4,8-di-tert-butyl-2-(4-methylphenyl)-
2H-naphtho[1,8-bc]furan (IIa). A solution of 0.374 g
(1 mmol) of 4,8-di-tert-butyl-5-hydroxy-2-(4-methyl-
phenyl)-2H-naphtho[1,8-bc]furan (Ia) and 0.082 g
(1 mmol) of sodium acetate in 2 ml of acetic anhydride
was boiled for 15 min, cooled, and poured in water. On
hydrolysis of excess anhydride the separated precipitate
was filtered off and crystallized from hexane, yield
0.303 g (73%), light-yellow substance, mp 133–135°C.
EXPERIMENTAL
IR spectra of compounds obtained were registered
on a spectrophotometer Specord IR-71 from mulls in
mineral oil. H NMR spectra were obtained on
–1
IR spectrum: n 1767 cm (C=O). 1H, d, ppm: 1.4 d [18H,
1
(CMe3)2], 2.4 s (3H, Me), 2.5 s (3H, OCOMe), 6.75 s
(1H, furan), 6.9 d (1H, naphth.), 7.1 s (1H, naphth.),
7.2 d (2H, tolyl), 7.25 d (2H, tolyl), 7.45 d (1H, naphth.).
Found, %: C 81.13; H 7.51. C28H32O3. Calculated, %:
C 80.77; H 7.69.
spectrometers Bruker Avance DPX-250 and Varian
Unity-300 from solutions in CDCl3; internal reference
HMDS. Mass spectrum was measured on a Kratos
instrument with a direct admission of a sample into the
ionizing chamber, ionizing electrons energy 70 eV,
controlling voltage 1.75 kV.
Compounds IIb, c were prepared in a similar way.
5-Acetoxy-4,8-di-tert-butyl-2(4-methoxyphenyl)-
2H-naphtho[1,8-bc]furan (IIb). Yield 70%, mp 160°C.
X-ray diffraction analysis of compound Va was
carried out using a single crystal of linear dimensions
0.29´0.27´0.25 mm, C28H32O4, M 432.54, at 120(2) K
on a diffractometer Bruker SMART CCD area detector
(lMOKa-radiation, qmax 27.99°, spherical segment –9 £
h £ 9, –16 £ k £ 16, –16 £ l £ 17). Overall 11118 reflec-
tions were obtained, 4155 among them were symmetrical-
ly independent (Rint 0.0442). Triclinic crystals, space
–1
IR spectrum: n 1767 cm (C=O). 1H NMR spectrum,
d, ppm: 1.4 d [18H, (CMe3)2], 2.4 s (3H, COMe), 3.8 s
(3H, OMe), 6.85 d (1H, naphth.), 6.9 d (2H, anisyl), 7.1 s
(1H, naphth.), 7.3 d (2H, anisyl), 7.4 d (1H, naphth.).
Found, %: C 77.43;H 75.8. C28H32O4. Calculated, %:
C 77.78; H 7.41.
°
5-Acetoxy-4,8-di-tert-butyl-2-(3,4-dimethoxy-
phenyl)-2H-naphtho[1,8-bc]furan (IIc). Yield 75%,
group P-1, a 7.3820, b 12.3768, c 13.0135 A, a 94.828(2),
°
b 101.279(3), g 100.343(3)°, V 1138.3(2) A3, Z 2,
–1
1
–3
–1
mp 98°C. IR spectrum: n 1767 cm (C=O). H NMR
spec-trum, d, ppm: 1.4 d [18H, (CMe3)2], 2.5 s (3H,
COMe), 3.8 s (3H, OMe), 3.9 s (3H, OMe), 6.75 s (1H,
furan), 6.9 m (3H, arom), 7.0 d (1H, veratr.), 7.1 s (1H,
veratr.), 7.25 s (1H, naphth.), 7.45 d (1H, naphth.). Found,
%: C 75.53; H 7.48. C29H34O5. Calculated, %: C 75.34;
H 7.36.
dcalc 1.262 g cm , m 0.083 mm , F (000) 464.0. The
structure was solved by the direct method, all
nonhydrogen atoms were localized by difference
synthesis of the electron density and refined by F2hkl in
the full-matrix anisotropic approximation. All hydrogen
atoms were placed into the geometrically calculated
positions and refined with the use of the rider model
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005

BUILDING UP OF A peri-HYDROXYNAPHTHOYL FRAGMENT
231
5-Acetoxy-6-acetyl-4,8-di-tert-butyl-2-(4-
methoxyphenyl)-2H-naphtho[1,8-bc]furan (IVb).
To a cooled dispersion of 0.097 g (0.25 mmol) of 4,8-di-
tert-butyl-5-hydroxy-2-(4-methoxyphenyl)-2H-naphtho-
[1,8-bc]furan (Ib) in 1 ml of acetic acid was added
0.01 ml of perchloric acid, the mixture was kept for
15 min and then poured in water. The precipitate obtained
was filtered off and crystallized from ethanol to obtain
0.104 g (87%) of colorless substance, mp 149–151°C.
IR spectrum: n 1750(C=O), 1673 cm (C=O). H NMR
spectrum, d, ppm: 1.4 d [18H, (CMe3)2], 2.4 s (3H,
OCOMe), 2.6 s (3H, COMe) 3.8 s (3H, OMe), 6.75 s
(1H, furan), 6.9 d (2H, anisyl), 7.2 m (3H, arom), 7.7 s
(1H, veratr.). Found, %: C 75.68; H 7.32. C30H34O5.
Calculated, %: C 75.95; H 7.17.
4,8-Di-tert-butyl-2-(4-methoxyphenyl)-5-pro-
pionyloxy-2H-naphtho[1,8-bc]furan (IId). A solution
of 0.39 g (1 mmol) of 2-(4-methylphenyl)-4,8-di-tert-butyl-
5-hydroxy-2H-naphtho[1,8-bc]furan (Ib) and 0.082 g
(1 mmol) of sodium acetate in 2 ml of propionic anhydride
was boiled for 15 min, cooled, and poured in water. On
hydrolysis of excess anhydride the separated precipitate
was filtered off and crystallized from hexane. Yield 0.3 g
(67%), light-yellow substance, mp 92°C. IR spectrum:
n 1767 cm (C=O). H NMR spectrum, d, ppm: 1.4 d
[18H, (CMe3)2], 1.6 t (3H, CH2CH3), 2.7 q (2H,
CH2CH3), 3.8 s (3H, OMe), 6.75 s (1H, furan), 6.8 d
(1H, naphth.), 6.9 d (2H, anisyl), 7.1 s (1H, naphth.),
7.3 d (2H, anisyl), 7.4 d (1H, naphth.). Found, %: C 78.27;
H 7.47. C29H34O4. Calculated, %: C 78.03; H 7.39.
–1
1
–1
1
Likewise were obtained compounds IVa, IVc, IVd.
4,8-Di-tert-butyl-5-hydroxy-2-(4-methylphenyl)-
6-formyl-2H-naphtho[1,8-bc]furan (IIIa). To a cooled
dispersion of 0.208 g (0.5 mmol) of 5-acetoxy-4,8-di-tert-
butyl-2-(4-methylphenyl)-2H-naphtho[1,8-bc]furan (IIa)
in 1 ml of 1,1,2,2-tetrachloroethane was added by portions
while stirring 0.1 g (0.75 mmol) of anhydrous aluminum
chloride, the mixture was maintained for 4 h and then
poured in water. The precipitate obtained was filtered
off, dried, and subjected to chromatography on alumina
(eluent benzene), yield 0.109 g (54%), golden crystalline
5-Acetoxy-6-acetyl-4,8-di-tert-butyl-2-(4-methyl-
phenyl)-2H-naphtho[1,8-bc]furan (IVa), yield 80%, mp
–1
106–108°C. IR spectrum: n 1755 (C=O), 1673 cm
(C=O). 1H NMR spectrum, d, ppm: 1.4 d [18H, (CMe3)2],
2.35 s (3H, Me), 2.38 s (3H, OCOMe), 2.65 s (3H,
COMe), 6.8 s (1H, furan), 7.25 m (5H, arom), 7.7 s (1H,
naphth.). Found, %: C 78.81; H 7.32. C30H34O4.
Calculated, %: C 78.60; H 7.42.
5-Acetoxy-6-acetyl-4,8-di-tert-butyl-2-(3,4-di-
methoxyphenyl)-2H-naphtho[1,8-bc]furan (IVc),
yield 77%, mp 104°C. IR spectrum: n 1673 (C=O),
–1
substance, mp 85–88°C. IR spectrum: n 1635 cm
(C=O). 1H NMR spectrum, d, ppm: 1.4 d [18H,(CMe3)2],
2.3 s (3H, Me), 6.7–7.9 m (7H, arom) 9.5 s (1H, CHO),
12.35 s (1H, OH). Found, %: C 80.42; H 7.32. C27 H30O3.
Calculated, %: C 80.60; H 7.46.
–1
1747 cm (C=O). 1H NMR spectrum, d, ppm: 1.4 d
[18H, (CMe3)2], 2.35 s (3H, OCOMe), 2.62 s (3H,
COMe), 4.8 s (3H, OMe), 4.9 s (3H, OMe), 6.7–7.0 m
(4H, arom), 7.2 s (1H, arom), 7.7 d (1H, arom). Mass
spectrum, m/z: 504 M+.
Likewise were prepared compounds IIIb, IIIc.
4,8-Di-tert-butyl-5-hydroxy-2-(3-formyl-4-
methoxyphenyl)-6-formyl-2H-naphtho[1,8-bc]furan
(IIIb), yield 35%, mp 105–107°C. IR spectrum: n 1647
4,8-Di-tert-butyl-2-(3,4-dimethoxyphenyl)-5-
propionyloxy-6-propionyl-2H-naphtho[1,8-bc]-furan
(IVd). To a cooled dispersion of 0.42 g (1 mmol) of 4,8-
di-tert-butyl-5-hydroxy-2-(3,4-dimethoxyphenyl)-2H-
naphtho[1,8-bc]furan (Ic) in 2 ml of propionic anhydride
was added 0.01 ml of perchloric acid, the mixture was
kept for 30 min and then poured in water. The precipitate
obtained was filtered off and subjected to chromatography
on alumina (eluent chloroform) to isolate 0.104 g (87%)
of colorless substance, mp 88°C. IR spectrum: n 1753
1
(C=O), 1687 cm–1 (C=O). H NMR spectrum, d, ppm:
1.4 d [18H, (CMe3)2], 3.95 s (3H, OMe), 6.85 C (1H,
furan), 7.0 d (1H, benz.), 7.2 C (1H, naphth.), 7.4 d (1H,
benz.), 7.85 s (1H, benz.), 7.95 s (1H, naphth.), 9.6 s
(1H, CHO), 10.4 s (1H, CHO), 12.4 s (1H, OH). Found,
%: C 75.42; H 6.79. C28 H30O5. Calculated, %: C 75.34;
H 6.73.
4,8-Di-tert-butyl-5-hydroxy-2-(3,4-dimethoxy-
phenyl)-6-formyl-2H-naphtho[1,8-bc]furan (IIIc),
1
(C=O), 1687 cm–1 (C=O). H NMR spectrum, d, ppm:
1.2 t [6H, (CH2CH3)2], 1.4 d [18H, (CMe3)2], 2.7 br.m
(2H, CH2CH3), 3.8 q (2H, CH2CH3), 3.9 s (3H, OMe),
6.75–7.6 m (7H, arom). Found, %: C 73.68; H 7.81.
C32H40O6. Calculated, %: C 73.85; H 7.69.
–1
yield 24%, mp 70–73°C. IR spectrum: n 1635 cm
(C=O). 1H NMR spectrum, d, ppm: 1.4 d [18H, (CMe3)2],
3.8 s (3H, OMe), 3.9 s (3H, OMe), 6.75 s (1H, furan),
6.85–6.95 m (3H, benz.), 7.25 s (1H, naphth.), 7.9 s (1H,
naphth.), 9.6 s (1H, CHO), 12.4 s (1H, OH). Found, %:
C 75.24; H 7.31. C28H32O5. Calculated, %: C 75.0; H 7.14.
5-Acetoxy-6-benzoyl-4,8-di-tert-butyl-2-(4-
methoxyphenyl)-2H-naphtho[1,8-bc]furan (IVe). To
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232
TYURIN et al.
butyl-5-hydroxy-2-(3,4-dimethoxyphenyl)-2H-naphtho-
[1,8-bc]furan (Vb) in 2 ml of benzene was added a
solution of 0.251 g (1 mmol) of K3[Fe(CN)6] and 0.075 g
of NaOH in 4 ml of water, and the mixture was stirred
with a magnetic stirrer at 70°C for 1 h. Then the benzene
solution was evaporated, and the residue was subjected
to column chromatography on alumina (eluent
chloroform). The first fraction was collected. Yield
0.308 g (67%), yellow substance, mp 189–190°C. IR
spectrum: n 1700 (C=O), 1630 cm–1 (C=O). 1H NMR
spectrum, d, ppm: 1.5 d [18H, (CMe3)2], 2.6 s (3H,
COMe), 4.0 d (6H, OMe), 7.05 d (1H, veratr.), 7.2 s
(1H, naphth.), 7.5 s (1H, veratr.), 7.65 d (1H, veratr.),
7.9 s 1H, naphth.). Found, %: C 75.81; H 7.04. C29H32O5.
Calculated, %: C 75.65; H 6.96.
a cooled dispersion of 0.268 g (0.5 mmol) of 5-acetoxy-
4,8-di-tert-butyl-2-(4-methoxyphenyl)-2H-naphtho-
[1,8-bc]furan (IIb) in 1 ml of 1,1,2,2-tetrachloroethane
was added 0.196 ml (0.75 mmol) of benzoyl chloride and
then by portions at stirring also 0.1 g (0.75 mmol) of
anhydrous aluminum chloride. The mixture was kept for
4 h at room temperature and then poured in water. The
precipitate obtained was filtered off, dried, and subjected
to column chromatography on alumina (eluent benzene).
Yield 0.064 g (12%), yellow substance, mp 128–130°C.
IR spectrum: n 1660(C=O), 1760 cm (C=O). H NMR
spectrum, d, ppm: 1.4 d [18H, (CMe3)2], 2.36 s (3H,
OCOMe), 3.8 s (3H, OMe), 6.8–7.9 m (12H, arom).
Found, %: C 78.45; H 6.63. C35H36O5. Calculated, %:
C 78.36; H 6.72.
–1
1
6-Acetyl-4,8-di-tert-butyl-5-hydroxy-2-(4-
methoxyphenyl)-2H-naphtho[1,8-bc]furan (Va).
To a dispersion of 0.474 g (1 mmol) of 5-acetoxy-6-acetyl-
4,8-di-tert-butyl-2-(4-methoxyphenyl)-2H-naphtho-
[1,8-bc]furan (IVb) in 3 ml of methanol was added 3 ml
of sodium methylate saturated solution in methanol, and
the mixture was stirred for 30 min. Then the solution
was poured in water and acidified with a dilute
hydrochloric acid to weakly acidic pH. The precipitate
obtained was filtered off, dried, and subjected to column
chromatography on alumina (eluent chloroform). The first
fraction was collected. Yield 0.15 g (32.5%), yellow
substance, mp 124–125°C. IR spectrum: n 2500 (OH),
REFERENCES
1. Mezheritskii, V.V. and Tkachenko, V.V., Adv. Heterocyclic
Chem. New York:Acad. Press, 1991, vol. 51, p. 1.
2. Dokunikhin, N.S. and Vorozhtsov, G.N., Dokl. Akad. Nauk
SSSR, 1968, vol. 179, p. 852.
3. Bystritskii, G.I., Vorozhtsov, G.N., Dokunikhin, N.S., and
Ovsyannikova, S.V. , Zh. Org. Khim., 1975, vol. 11, p. 1738.
4. Dalvi, S.S., and Seshadri, S., Indian J. Chem., 1985,
vol. 24B, p. 377.
5. Carey, J.L., Shand, C.A., Thomson, R.H., and Green-
halgh, C.W., J. Chem. Soc., Perkin Trans. I, 1984, p. 1957.
6. Tyurin, R.V., Minyaeva, L.G., and Mezheritskii, V.V., Zh. Org.
Khim., 2004, vol. 40, p. 1349.
7. Mezheritskii, V.V., Zhukovskaya, O.N., Tkachenko, V.V., and
Dorofeenko, G.N., Zh. Org. Khim., 1979, vol. 15, p. 196.
8. Reiche, A., Gross, H., and Hoff, E., Chem. Ber., 1960,
vol. 93, p. 88.
–1
1
1625 Cm (C=O). H NMR spectrum, d, ppm: 1.4 d
[18H, (CMe3)2], 2.8 s (3H, COMe), 3.8 s (3H, OMe),
6.8 s (1H, furan), 6.9 d (2H, anisyl), 7.2 m (3H, arom),
8.25 s (1H, naphth.), 12.8 s (1H, OH). Found, %: C 77.85;
H 7.36. C28H32O4. Calculated, %: C 77.78; H 7.41.
9. Thomas, C.A., Moshier, M.B., Morris, H.E., and Mo-
shier, R.W., Anhydrous Aluminum Chloride in Organic
Chemistry, NewYork: Reinhold, 1941.
10. Pozharskii,A.F., Usp. Khim., 2003, vol. 72, p. 498.
11. Martin, R.H., Defay, N., and Greets-Evrard, F., Tetrahedron,
1964, vol. 20, p. 1505.
12. Schweizer, W.B., Procter, G., Kaftory, M., and Dunitz, J.D.,
Helv. Chem. Acta, 1978, vol. 61, p. 2783.
13. O’Leary, J., Bell, P.C., Wallis, J.D., and Schweizer, W.B.,
J. Chem. Soc., Perkin Trans. I, 2001, p. 133.
Compound Vb was prepared in the same way.
6-Acetyl-4,8-di-tert-butyl-5-hydroxy-2-(3,4-
dimethoxyphenyl)-2H-naphtho[1,8-bc]furan (Vb),
yield 32.5%, mp 146–147°C. IR spectrum: n 2500 (OH),
–1
1
1620 cm (C=O). H NMR spectrum, d, ppm: 1.4 d
[18H, (CMe3)2], 2.8 s (3H, COMe), 3.75 s (3H, OMe),
3.9 s (3H, OMe), 6.7 s (1H, furan), 6.9 m (3H, veratr.),
7.2 s (1H, naphth.), 8.2 s (1H naphth.), 12.8 s (1H, OH).
Found, %: C 75.39; H 7.21. C29H34O5. Calculated, %:
C 75.33; H 7.36.
14. Clayden, J., McCarthy, C., Helliwell, M., Chem. Commun.,
1999, p. 2059.
15. Mezheritskii, V.V., Pikus,A.L., and Tregub, N.G., Zh. Org.
Khim., 1991, vol. 27, p. 2198.
6-Acetyl-4,8-di-tert-butyl-2-(3,4-dimethoxy-
phenyl)-2H-naphtho[1,8-bc]furan-5-one (VI).
To a solution of 0.462 g (1 mmol) of 6-acetyl-4,8-di-tert-
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 2 2005