Synthesis of Precursors for the Pyrolytic Formation of Pentatetraenones

Article abstract of DOI:10.1071/CH98174

3-(9',10'-Dihydro-9',10'-ethanoanthracen-11'-ylidene)prop-2-enoyl chloride and its [12',12'-2H2] and [1-13C] isotopomers have been prepared and pyrolysed. Argon matrix infrared spectroscopy showed ν₂ bands at 2207.7, 2207.0, and 2168.5 cm^-1 respectively for the three pentatetraenone isotopomers. The pyrolysate of the 12'-methyl substituted precursor showed a band at 2205 cm^-1 which was tentatively assigned to methylpentatetraenone. The 12'-ethenyl substituted precursor gave a pyrolysate showing ketene bands but also yielded 9,10-dihydro-9,10[1',2']-benzenoanthracene.

Full text of DOI:10.1071/CH98174

C S I R O P U B L I S H I N G
Australian Journal
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Volume 52, 1999
© CSIRO Australia 1999
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Aust. J. Chem., 1999, 52, 663–672
.
Synthesis of Precursors for the
Pyrolytic Formation of Pentatetraenones
Phillip Arena, Roger F. C. Brown, Frank W. Eastwood
and Don McNaughton
Chemistry Department, Monash University, Clayton, Vic. 3168.
3-(90,100-Dihydro-90,100-ethanoanthracen-110-ylidene)prop-2-enoyl chloride and its [120,120-2H2] and [1-
13C] isotopomers have been prepared and pyrolysed. Argon matrix infrared spectroscopy showed
2
1
bands at 2207 7, 2207 0, and 2168 5 cm respectively for the three pentatetraenone isotopomers. The
1
pyrolysate of the 120-methyl substituted precursor showed a band at 2205 cm which was tentatively
assigned to methylpentatetraenone. The 120-ethenyl substituted precursor gave a pyrolysate showing
ketene bands but also yielded 9,10-dihydro-9,10[10,20]-benzenoanthracene.
The geometries of ethenone1 and those of the
more exible cumulenones, namely propadienone2 and
butatrienone,3 have been determined and their spec-
troscopic properties have been compared with those
calculated by a variety of methods. Argon matrix
infrared spectroscopic evidence that the next mem-
ber of the series, pentatetraenone, H2C5O, had been
prepared was presented in 1988.4 This rst synthesis
of pentatetraenone was achieved by pyrolytic meth-
ods using ve di erent precursors. The frequencies
describe the synthesis of precursors which appear to
fragment in this manner.
9 ,10-Dihydro-9 ,10-ethanoanthracene-11-carbonyl
chloride (1) was converted into the allenic ester (2) by
using the method of Lang and Hansen.6 Best results
were obtained by adding methyl (triphenylphospho-
ranylidene)ethanoate and triethylamine to a solution
of the acid chloride in boiling ethanol-free chloro-
form. The resulting ester (2) could not readily be
puri ed and was unstable and it was hydrolysed to
the stable allenic acid (3). The acid chloride (4),
which was prepared from the acid and oxalyl chloride,
served as the pyrolytic precursor. The synthesis was
repeated with methyl (triphenylphosphoranylidene)[1-
13C]ethanoate which had been diluted to 50 atom %
13C to give the labelled allenic acid chloride (5).
To obtain the dideuterated precursor (8), methyl
propenoate was heated in deuterium oxide in the pres-
ence of potassium chloroplatinate and hydroquinone.7
The crude deuterated product was extracted into
xylene and reacted directly with anthracene. The
resulting ester was hydrolysed and the 9,10-dihydro-
9,10-ethanoanthracene-11-carboxylic acid (6) was found
to be deuterated at the 11-position (53%) and at the
12-position (50%), as estimated by 1H n.m.r. spec-
troscopy. After conversion of the acid (6) into the
allenic acid (7), the 120-position remained 50% deuter-
ated. The allenic acid (7) was then converted into the
acid chloride (8).
assigned to the high-intensity C=C=C=O vibration
1
2207 cm
and the corresponding band for the
2
H2C413C=O isotopomer at 2168 cm were compared
with those calculated for the molecule by using models
based on force constants taken from ethenone, allene
and tricarbon monoxide. The numbering system for
the vibration modes is according to C2v symmetry.
Recently, East5 has discussed the various methods
used for determining the ‘kinkiness’ of cumulenones
and has concluded that, based on calculations for the
1
frequency of the
band, there is strong evidence
2
that pentatetraenone had been prepared in this earlier
work.
The ve precursors used in that work were di cult
to synthesize and each on fragmentation gave rise to
cyclopentadiene, a compound with a permanent dipole
moment and consequently a microwave absorption
spectrum. It may be possible in the future to de ne
the geometry of pentatetraenone by determining its
microwave spectrum in a pyrolysate stream and we
sought to prepare a precursor which could be made in
su cient quantity to permit its use in a ow system
and which would fragment to yield hydrogen chloride,
anthracene, and pentatetraenone. In this paper we
Pyrolysis of the unlabelled precursor (4) at 650
in a ow of argon, collection as a matrix at 10 K
and measurement of the infrared spectrum gave strong
1
absorption at 2207 7 cm
which was attributed to
of pentatetraenone. This band was not detected
2
Manuscript received 1 December 1998
᭧ CSIRO 1999
0004-9425/99/070663$ 05.00
10.1071/CH98174

664
P. Arena et al.
when the acid chloride was pyrolysed at 550 , and
when the precursor was pyrolysed at 750 the matrix
1
showed a band at 2207 cm
of only low intensity.
Similarly, pyrolysis at 650 of the [1-13C] isotopomer
(5) containing 50 atom % 13C gave a matrix show-
1
ing bands at 2207 4 and 2168 5 cm
assigned to the
which were
bands of pentatetraenone and
2
[1-13C]pentatetraenone respectively. Pyrolysis of the
120,120-dideuterated compound (8) at 650 gave a
matrix with strong absorption at 2207 0 cm 1. We
consider that this compound fragmented to a mixture
of pentatetraenone and dideuterated pentatetraenone.
The absorption due to the
band would appear to
2
be only perturbed to a minor degree by the remote
deuterium atoms so that there is little observed change
in the absorption due to the mixture.
An attempt to obtain a continuous ow of pentate-
traenone in a microwave study failed. Heating the
precursor to induce slow volatilization into the pyrolysis
tube caused decomposition (the slow introduction of
a mull of the precursor in vacuum grease is proposed
as a solution to this problem).
by Maquestiau et al.10 showed that fragmentation
of such compounds was complex. The ethylidene
The initial attempt to synthesize methylpropa-
dienone, CH3CH=C=C=O, by pyrolysis of 5-ethylidene-
2,2-dimethyldioxan-4,6-dione resulted in a complex
mixture but trapping the pyrolysate in the gas phase
with aniline led to the isolation of but-3-enanilide,
arising from vinylketene.8 Studies on the pyrolysis
of 5-cyclopentylidene-2,2-dimethyldioxan-4,6-dione by
Wentrup et al.9 and of the 5-ethylidene derivative
derivative fragmented to vinyl(carboxy)ketene (
max
2135 cm 1) which decarboxylated to methylpropa-
dienone (
2093 cm 1).
The facile pyrolytic
conversion of methylpropadienone into vinylketene
2118 cm 1) was con rmed.10 Similar results
max
(
max
were obtained on pyrolysis of 5-isopropylidene-2,2-
dimethyldioxan-4,6-dione which on fragmentation gave
isopropenyl(carboxy)ketene (
2125 cm 1) which
max
decarboxylated to yield dimethylpropadienone (
max
2088 cm 1). Conversion of dimethylpropadienone
into isopropenylketene (
2109 cm 1) was found
max
to require vigorous conditions.10 Methylbutatrienone,
CH3CH=C=C=C=O, is not a known compound but
dimethylbutatrienone (
2224, 2216 cm 1) has been
max
prepared by pyrolysis of a speci c precursor.11 We
have sought to synthesize methylpentatetraenone using
elimination of hydrogen chloride and anthracene as
described above for pentatetraenone.
trans-12-Methyl-9,10-dihydro-9,10-ethanoanthra-
cene-11-carboxylic acid (9) was prepared from but-
2-enoic acid and anthracene and converted via the
acid chloride into a mixture of E- and Z-allenic esters
(10). In this reaction there was also formed some of
the triphenylphosphorane (11). The ester (10) was
hydrolysed to a mixture of the E- and Z-acids (12),
which was converted into a mixture of acid chlorides
(13) with oxalyl chloride.
Pyrolysis of the acid chlorides (13) in a stream of
argon, deposition of a matrix at 10 K and measurement
of the infrared spectrum showed an absorption band
at 2205 1 cm 1. We suggest that this could be due to
methylpentatetraenone. However, the possibility that
this compound could rearrange to vinylbutatrienone
(hexa-1,2,3,5-tetraen-1-one) (15) cannot be disregarded.
There is also the possibility that a 1,5-hydrogen shift
could give rise to hexa-1,5-dien-3-yn-1-one. An alter-

Precursors of Pentatetraenones
665
native 1,5-hydrogen shift could lead to the aldehyde
hexa-2,4-diynal.
On the basis of these ndings we suggest that long-
chain ketenes are formed in these pyrolyses. However,
we cannot say with certainty whether vinylpentate-
traenone is formed. What we can say is that none
of the ketene absorption bands observed in this work
In a study on the pyrolytic generation of cyclopen-
tadienylideneethenone (14) (
2089 cm 1) it was
max
found that the precursors derived from Meldrum’s acid
1
(2,2-dimethyldioxan-4,6-dione) when pyrolysed showed
correspond to the band at 2225 cm observed in the
1 12
not only the band at 2089 but also one at 2225 cm
.
earlier work.12 It is clear also that besides elimination
of the ketene with formation of anthracene there is a
cyclization involving loss of HCl and CO which leads
to the formation of a benzene ring and yields 9,10-
dihydro-9,10[10,20]-benzenoanthracene which is stable
to pyrolysis under the conditions used. However, there
is no evidence concerning the reaction pathway.
1
This latter frequency was shifted downwards by 40 cm
on 13C substitution of the carbonyl carbon atom. This
ketene could not be identi ed but because the isotopic
shift was comparable with that observed (39 cm 1) on
13C substitution in pentatetraenone (39 cm 1) it was
suggested that fragmentation of the cyclopentadiene
ring might lead to vinylpentatetraenone (15). We have
explored the possibility of preparing this compound
using the ethenyl precursor (26).
Conclusion
The results indicate that these new precursors pro-
vide a simple method for obtaining pentatetraenones.
However, structural assignments based solely on matrix
infrared spectrometric measurements are not considered
to be de nitive.
9,10-Dihydro-9,10-ethanoanthracene-11,12-dicar-
boxylic anhydride (16) was reduced with disodium
tetracarbonylferrate sesquidioxanate13 to the lactol
(17). Dissolution of the lactol in aqueous potassium
hydroxide and acidi cation gave the trans formyl car-
boxylic acid (18). Conversion of this acid into the
methyl ester (19) followed by methylenation by a Wittig
reaction gave the trans ethenyl-substituted ester (20).
This ester was hydrolysed under alkaline conditions
and the resulting acid (21) converted into the acid
chloride (22) with oxalyl chloride. Reaction of the
acid chloride (22) with methyl (triphenylphosphoranyli-
dene)ethanoate and triethylamine in chloroform gave a
43% yield of the required allenic ester (23) together with
a 40% yield of the triphenylphosphorane (24). Hydrol-
ysis of the allenic ester with lithium hydroxide and
acidi cation gave a mixture of the E- and Z-isomers of
the ethenyl allenic acid (25). Treatment of this mixture
with oxalyl chloride gave the mixture of acid chlorides
(26) used as the pyrolytic precursor. The synthesis was
repeated with methyl (triphenylphosphoranylidene)[1-
13C]ethanoate containing 50 atom % 13C which resulted
in the precursor mixture (27).
Experimental
Melting points were determined by using a Reichert hot-stage
melting point apparatus and are uncorrected. Infrared spectra
were recorded on a Perkin–Elmer 1640 Fourier-transform i.r.
spectrometer. 1H and 13C n.m.r. spectra were recorded on
Bruker AC-200 and AM-300 spectrometers. Values shown for
coupling constants J are frequency di erences taken directly
from spectra. Carbon resonances were assigned with the assis-
tance of a J-MODXH pulse sequence. Mass spectra were measured
with a VG Trio-1 spectrometer at 70 eV. Accurate mass values
were determined on a VG Micromass 7070F spectrometer.
Silica gel used for ash chromatography was Merck Kieselgel
60, particle size 0 040–0 063 mm (230–400 mesh), Art. 9385.
Light petroleum refers to the fraction of b.p. 55–68 . Gas–liquid
chromatogram/mass spectra (g.c.–m.s.) were recorded with a
Hewlett–Packard gas liquid chromatograph coupled to a VG
Trio-1 spectrometer via an S.G.E. open split interface of ratio
50 : 1.
In matrix experiments argon–precursor mixtures were passed
through a quartz tube (420 by 20 mm i.d.) heated with an
external furnace (Lindberg tube 55035). The temperature was
monitored with a chromel/alumel thermocouple midway along
the external wall of the tube. The exit from the tube turned
90 and was joined through a 10-mm tap to a sample chamber
containing a copper-mounted CsI plate cooled with a CTI
Cryodyne 21 refrigerator. The deposition rate was controlled
by the ow of argon (Hoke vernier needle valve) and monitored
by pressure measurement. After deposition was complete the
sample chamber was isolated and the CsI plate rotated 90
for infrared spectroscopic measurement. Volatile samples were
mixed with argon and placed in a 100-ml reservoir attached
to a 1000-ml reservoir on the vacuum line. Solids or low
vapour pressure liquids were placed in a small glass vial near
the entrance to the pyrolysis tube and volatilized by heating
in a stream of argon. Infrared measurements were made on
Pyrolysis of the precursor (26) gave unsatisfactory
results but pyrolysis of the precursor (27) containing
50% 13C in the carbonyl group gave clearer spectra.
Bands due to CO2 and a small amount of 13CO2
1
were evident and those due to CO (2138 5 cm
)
and 13CO (2091 3 cm 1) were of equal intensity. The
pyrolysate obtained at 550 showed a small band
1
at 2154 3 cm
.
The pyrolysates obtained at 650
and at 750 showed sharp bands at 2154 2 and
1
2106 6 cm
.
These bands were attributed to an
unlabelled and labelled ketene and the decrease in
1
frequency on labelling of 47 7 cm
suggests that
a Bruker IF6 120 HR interferometer using the spectral range
1
the product could be a pentatetraenone derivative.
After measurement of each spectrum the CsI plate
was allowed to warm to room temperature and the
pyrolysate was examined by g.c.–m.s. The same two
products were identi ed in each pyrolysate. The com-
pounds were anthracene and 9,10-dihydro-9,10[10,20]-
benzenoanthracene.
4000–650 cm
.
9,10-Dihydro-9,10-ethanoanthracene-11-carboxylic Acid
Methyl 9,10-dihydro-9,10-ethanoanthracene-11-carboxylate,
1
m.p. 117–118 ,
1729 cm [1H n.m.r. (200 MHz, CDCl3)
max
7 33–7 15, m, 4H, 7 14–7 06, m, 4H, aromatic; 4 68, d, J 2 5
Hz, H 10; 4 34, t, J 2 7 Hz, H 9; 3 59, s, OCH3; 2 93–2 84, m,
H 11; 2 21–1 93, m, (H 12)2. 13C n.m.r. (50 MHz, CDCl3)

666
P. Arena et al.
173 97, C=O; 143 85, 143 57, 142 39, 139 95, C 4a, C 8a, C 9a,
C 10a; 126 18, 126 11, 125 70 (2C), 124 68, 123 62, 123 42,
123 22, C 1–8; 51 87, OCH3; 46 75, C 11; 43 96, 43 77, C 9,
C 10; 30 70, C 12. Mass spectrum, m/z 264 (M, 1 5%), 178
(100)], was prepared in 66% yield by reaction of anthracene with
methyl propenoate.14 Hydrolysis of the ester with potassium
hydroxide gave the title acid, m.p. 191–192 (lit.15 191–193 ),
in 88% yield. The acid was more readily prepared by heating
anthracene (4 0 g, 22 mmol) and propenoic acid (3 03 g, 33
mmol) in toluene (10 ml) under re ux for 48 h. The cooled
mixture was extracted with aqueous sodium hydroxide (100
ml, 10%) and the aqueous extract was washed with ether
(2 50 ml). The alkaline solution was acidi ed to pH 1 with
concentrated hydrochloric acid and allowed to stand at room
temperature overnight. The precipitated acid was collected by
hydrochloric acid. The precipitated material was isolated by
extraction of the mixture with ether. The ethereal extracts
were combined, dried (MgSO4), and evaporated under vacuum
to give a yellow crystalline solid. The product was recrystallized
from ether/light petroleum to give the title acid (3) as a pale
yellow powder (3 94 g, 40%), m.p. 212–214 (Found: m/z,
274 099 0 003.
(Nujol) 1963 (C=C=C), 1680 cm
C19H14O2 requires m/z, 274 099).
max
(C=O). 1H n.m.r. (200
1
MHz, CDCl3) 7 39–7 29, m, 4H, 7 16–7 10, m, 4H, aromatic;
5 56, t, J 3 8 Hz, H 2; 4 89, s, H 100; 4 47, t, J 2 6 Hz,
H 90; 2 68–2 62, m, (H 120)2. 13C n.m.r. (50 MHz, CDCl3)
209 60, C 3; 171 80, C=O; 143 29, 143 10, 141 10, 140 42,
C 40a, C 80a, C 90a, C 100a; 126 60 (2C), 126 56, 126 43, 126 04,
123 91, 123 75, 123 70, C 10–80; 105 01, C 110; 89 29, C 2;
49 70, 44 24, C 90, C 100; 33 70, C 120. Mass spectrum, m/z
274 (M, 1%), 178 (100).
ltration, washed with water and dried (5 10 g, 91%), m.p.
1
191–192 ,
1703 cm
.
1H n.m.r. (200 MHz, CDCl3)
max
3-(9 0,10 0-Dihydro-9 0,10 0-ethanoanthracen-11 0-
ylidene)prop-2-enoyl Chloride (4)
11 1, br s, OH; 7 37–7 20, 4H, 7 19–7 07, 4H, aromatic; 4 72,
d, J 2 3 Hz, H 10; 4 38, t, J 2 4 Hz, H 9; 2 90–2 88, m,
H 11; 2 19–1 97, m, (H 12)2. 13C n.m.r. (50 MHz, CDCl3)
179 80, C=O; 143 68, 143 62, 142 27, 139 60, C 4a, C 8a,
C 9a, C 10a; 126 25, 126 19, 125 65, 125 75, 125 02, 123 63,
123 48, 123 13, C 1–8; 46 45, C 11; 43 99, 43 96, C 9, C 10;
30 46, C 12. Mass spectrum, m/z 250 (M, 4%), 178 (100).
Oxalyl chloride (0 02 ml, 0 20 mmol) was added to a solution
of the allenic acid (3) (20 mg, 0 07 mmol) in dichloromethane
(0 35 ml). The mixture was allowed to stand for 2 h where-
upon the excess of oxalyl chloride and dichloromethane were
evaporated under vacuum without heating. The title acid
chloride (4) was obtained quantitatively as a yellow powder,
m.p. 160–161 (Found: m/z, 292 065 0 001. C19H1335ClO
9,10-Dihydro-9,10-ethanoanthracene-11-carbonyl Chloride (1)
The acid obtained above was treated with oxalyl chloride
and dimethylformamide in dichloromethane under an atmo-
sphere of nitrogen as described by Friedrich and Schuster15 and
Brosshard et al.16 Crystallization of the product from hexane
requires m/z, 292 065).
1
(Nujol) 1953 (C=C=C), 1757
max
cm
(C=O). 1H n.m.r. (200 MHz, CDCl3) 7 37–7 25, m,
4H, 7 21–7 16, m, 4H, aromatic; 5 86, m, H 2; 5 03, s, H 100;
4 56, m, H 90; 2 75–2 58, m, (H 12)2. 13C n.m.r. (50 MHz,
CDCl3) 214 25, C 3; 165 86, C=O; 143 17, 143 00, 139 92,
139 49, C 40a, C 80a, C 90a, C 100a; 126 76, 126 62, 126 48,
126 22, 124 11, 123 91, 123 84, 123 72, C 10–80; 106 91, C 2;
49 52, 43 99, C 90, C 100; 34 14, C 120. Mass spectrum, m/z
294 (6 4%) 292 (M, 21), 179 (64), 178 (100).
gave the acid chloride (1) (94% yield), m.p. 116–118 (lit.15
1
120–123 ).
(Nujol) 1804 cm
.
1H n.m.r. (200 MHz,
max
CDCl3) 7 37–7 22, m, 4H, 7 17–7 10, m, 4H, aromatic; 4 84,
d, J 2 3 Hz, H 10; 4 36, t, J 2 7 Hz, H 9; 3 35–3 26, m, H 11;
2 16–2 06, m, (H 12)2. Mass spectrum, m/z 268 (M, 2%), 178
(100).
Methyl (Triphenylphosphoranylidene)[1-13C]ethanoate
3-(9 0,10 0-Dihydro-9 0,10 0-ethanoanthracen-11 0-
ylidene)prop-2-enoic Acid (3)
Methyl bromo(1-13C)ethanoate (1 1 g,
7 mmol, 99 4
atom % 13C) and triphenylphosphine (1 9 g, 7 2 mmol)
in ether yielded the quaternary bromide (2 6 g, 88%)
which on treatment with aqueous sodium hydroxide gave
methyl (triphenylphosphoranylidene)(1-13C)ethanoate (1 8 g,
94% yield, 99 4 atom % 13C), m.p. 168–169 . This was
mixed with an equal quantity of the unlabelled ylide to give
A solution of triethylamine (8 71 ml, 61 4 mmol) and
methyl (triphenylphosphoranylidene)ethanoate (20 27 g, 61 4
mmol) in ethanol-free chloroform (150 ml) was added dropwise
over 1 5 h to a boiling solution of the acid chloride (15 0
g, 56 0 mmol) in ethanol-free chloroform (250 ml) under an
atmosphere of nitrogen. The resulting red solution was heated
under re ux while the reaction was monitored by infrared
measurements and t.l.c. It was found that the allenic ester was
decomposing before all the acid chloride had reacted and after
1 h the heating was stopped. The solution was evaporated
under vacuum to one-third of the initial volume and then
washed with water (3 150 ml). The chloroform solution was
dried (CaCl2) and evaporated under vacuum to give a mixture
of oil and crystals. Ether was added, the solution was ltered
to remove the precipitated triphenylphosphine oxide, and the
ether was evaporated under vacuum. The product was puri ed
by ash chromatography (silica; dichloromethane) to give the
3 6 g of the title ylide (50 atom % 13C).
1618, 1582
max
1
cm
.
13C n.m.r. (50 MHz, CDCl3) 171 89, 171 64 (relative
intensities 8 1 : 10 4), C=O. Mass spectrum, m/z 335 (M, 5%,
C2013CH19O2P), 334 (10), 333 (20), 304 (10), 303 (28), 302
(75), 301 (100).
3-(9 0,10 0-Dihydro-9 0,10 0-ethanoanthracen-11 0-ylidene)[1-
13C]prop-2-enoic Acid
Reaction of the acid chloride (1) (700 mg, 2 5 mmol) with
methyl (triphenylphosphoranylidene)[1-13C]ethanoate (1 0 g,
4 1 mmol) in chloroform in the presence of triethylamine (0 8
ml, 4 0 mmol) as previously described gave the labelled ester
intermediate ester (2) as a yellow oil (10 4 g, 65%).
max
3022, 2950, 2845, 1964 (C=C=C), 1715 (C=O), 1480, 1436,
(2) as a colourless oil (500 mg, 67%).
1
1964 (C=C=C),
(200 MHz,
max
13C=O). 1H n.m.r.
1
1293, 1166, 1025, 769 cm
.
The 1H n.m.r. spectrum and
1717 (C=O), 1671 cm
(
the mass spectrum showed the ester to be contaminated with
triphenylphosphine oxide. The ester decomposed readily and
it was hydrolysed immediately.
The ester (10 4 g, 36 6 mmol) was added to a solution of
lithium hydroxide monohydrate (3 10 g, 135 mmol) in water
(80 ml) and 1,2-dimethoxyethane (80 ml) and the mixture was
stirred at room temperature for 48 h. Ether (50 ml) and
water (50 ml) were added and a small amount of white pre-
cipitate which formed was removed by ltration. The aqueous
phase was separated and acidi ed to pH 1 with concentrated
CDCl3) 7 37–7 19, m 4H, 7 17–7 10, m, 4H, aromatic; 5 61,
t, J 3 8 Hz, H 2; 4 88, s, H 100; 4 48, t, J 2 4 Hz, H 90; 3 65,
s ( anked by d, J 4 Hz), CH3; 2 69–2 62, m, (H 120)2. 13C
n.m.r. (50 MHz, CDCl3) 208 76, C 3; 166 55 (intense), C=O;
143 28, 143 18, 141 02, 140 58, C 40a, C 80a, C 90a, C 100a;
126 43, 126 38, 126 33, 126 28, 123 99, 123 77, 123 59 (2C),
C 10–80; 104 00, C 110; 89 32 ( anked by d, J 80 Hz), C 2;
51 48, 49 74, C 90, C 100; 44 20, CH3; 35 55, C 120. Mass
spectrum, m/z 289 (M, 1%, C1913CH16O2), 288 (1, C20H16O2),
179 (40), 178 (100).

Precursors of Pentatetraenones
667
Hydrolysis of the ester and crystallization of the product
from diethyl ether/light petroleum gave the title acid (labelled
(3)) as pale yellow crystals, m.p. 212–214 (Found: m/z,
126 37, 126 30, 125 87 (2C), 125 11, 123 74, 123 69, 123 27,
C 1–8; 46 61, C 11; 43 89, 43 68, C 9, C 10; C 12 was not
observed. Mass spectrum, m/z 254, 253 (2 3%, C17H112H3O2),
252, 251, 250 (abundance ratio 7 : 38 : 19 : 6 : 9), 178 (100).
275 102 0 005. C1813CH14O2 requires m/z, 275 102).
max
1
1963 (C=C=C), 1705 (C=O), 1668 cm
(
13C=O). 1H n.m.r.
[12,12-2H2]-9,10-Dihydro-9,10-ethanoanthracene-11-
carbonyl Chloride (6)
(200 MHz, CDCl3) 7 35–7 23, m, 4H, 7 18–7 06, m, 4H,
aromatic; 5 57, t, J 3 8 Hz, H 2; 4 90, s, H 100; 4 47, t, J 2 6
Hz, H 90; 3 38, s, OH (D2O exch.); 2 68–2 62, m, (H 120)2.
13C n.m.r. (50 MHz, CDCl3) 210 08, C 3; 171 06 (intense),
C=O; 143 17 (2C), 140 80, 140 32, C 40a, C 80a, C 90a, C 100a;
126 49 (2C), 126 45, 126 32, 123 96, 123 79, 123 64, 123 59,
C 10–80; 89 09 ( anked by d, J 80 Hz), C 2; 104 90, C 110;
49 61, 44 14, C 90, C 100; 33 60, C 120. Mass spectrum, m/z
275 (M, 2%), 274 (2), 179 (30), 178 (100).
The acid prepared above (400 mg) was converted into
the acid chloride (6) (420 mg, 98%) as previously described
(Found: m/z, 270 077 0 003. C17H112H235ClO requires m/z,
1
270 078).
1804 cm
(C=O). 1H n.m.r.
(200 MHz,
max
CDCl3) 7 37–7 26, m, 4H, 7 24–7 10, m, 4H, aromatic; 4 84,
d, J 2 5 Hz, H 10; 4 36, t, J 2 3 Hz, H 9; 3 35–3 26, m,
0 89H (11% 2H), H 11; 2 15–2 05, m, 1H (50% 2H), (H 12)2.
13C n.m.r. (50 MHz, CDCl3) 174 45, C=O; 143 57, 143 13,
141 12, 138 52, C 4a, C 8a, C 9a, C 10a; 126 79, 126 69,
126 17, 126 11, 125 17, 123 96, 123 66, 123 42, C 1–8; 56 09,
C 11; 46 94, 43 47, C 9, C 10; 31 77 (low intensity), C 12.
Mass spectrum, m/z 273, 272, 271, 270 (M, 4 5%), 269, 268
(abundance ratio 5 : 16 : 25 : 49 : 32 : 15), 204 (17), 178 (100).
3-(9 0,10 0-Dihydro-9 0,10 0-ethanoanthracen-11 0-ylidene)[1-
13C]prop-2-enoyl Chloride (5)
The acid (3) (50 atom % 13C) was converted, as previously
described, into the acid chloride (5) which was obtained as a
yellow powder, m.p. 158–160 (Found: m/z, 293 068 0 003.
C1813CH13O35Cl requires m/z, 293 068).
(C=C=C), 1749 (C=O), 1711 cm
(Nujol) 1955
max
(
13C=O). 1H n.m.r.
1
3-([12 0,12 0-2H2]-9 0,10 0-Dihydro-9 0,10 0-ethanoanthracen-
11 0-ylidene)prop-2-enoic Acid (7)
(200 MHz, CDCl3) 7 39–7 24, m, 4H, 7 19–7 13, m, 4H,
aromatic; 5 83, m, H 2; 5 00, s, H 100; 4 53, m, H 90; 2 71, m,
(H 120)2. 13C n.m.r. (50 MHz, CDCl3) 214 24, C 3; 165 87
(intense), 13C=O; 143 16, 143 00, 139 92, 139 49, C 40a, C 80a,
C 90a, C 100a; 126 76, 126 70, 126 62, 126 54, 124 11, 123 91,
123 84, 123 72, C 10–80; 106 91, C 110; 96 36 ( anked by d, J
80 Hz), C 2; 49 52, 43 99, C 90, C 100; 34 14, C 120.
Reaction of the deuterated acid chloride (6) (1 4 g, 5 2 mmol)
with methyl (triphenylphosphoranylidene)ethanoate (3 6 g, 11
mmol) and triethylamine (1 8 ml, 9 3 mmol) in ethanol-free
chloroform as previously described gave the deuterated ester
(860 mg, 58%) as a pale yellow oil.
1
1963 (C=C=C),
max
(C=O). 1H n.m.r. (200 MHz, CDCl3) 7 38–7 20,
1731 cm
m, 4H, 7 16–7 05, m, 4H, aromatic; 5 61, br s, H 2; 4 89, s,
H 100; 4 47, br s, H 90; 3 65, s, OCH3; 2 65–2 55, m, 1H (50%
Polydeuterated Methyl 9,10-Dihydro-9,10-ethanoanthracene-
11-carboxylate
2H), (H 120)2. 13C n.m.r.
(50 MHz, CDCl3) 208 80, C 3;
Methyl propenoate (3 4 g, 40 0 mmol), potassium chloro-
platinate (0 2 g, 0 50 mmol) and hydroquinone (0 1 g) were
added to deuterium oxide (19 ml) and the mixture was stirred
and heated at 90 in a stainless steel autoclave for 16 h.7 The
cooled mixture was extracted with xylene (80 ml), the xylene
layer separated, a small amount of polymer was discarded
and the solution was dried (Na2SO4) and used directly for
the next preparation. Anthracene (3 00 g, 170 mmol) was
added to the xylene solution and the mixture was heated
in an autoclave at 210 for 12 h.14 The resulting solution
was evaporated under vacuum and the residue recrystallized
166 70, C=O; 143 17, 143 15, 141 03, 140 59, C 40a, C 80a,
C 90a, C 100a; 126 42, 126 38, 126 33, 126 28, 126 14, 123 98,
123 78, 123 58, C 10–80; 89 31, C 2; 51 83, OCH3; 49 74,
C 110; 44 21, 44 12, C 90, C 100; 31 25 (low intensity), C 120.
This ester was hydrolysed with lithium hydroxide as previ-
ously described and the acidic product was crystallized from
diethyl ether/light petroleum to give the title acid (7) as a
yellow powder (450 mg, 56%), m.p. 215–216 (Found: m/z,
276 111 0 003. C19H122H2O2 requires m/z, 276 111).
max
1
(Nujol) 1963 (C=C=C), 1672 cm
(C=O). 1H n.m.r. (200
MHz, CDCl3) 7 36–7 29, m, 4H, 7 17–7 11, m, 4H, aromatic;
5 53, m, H 2; 4 89, s, H 100; 4 47, m, H 90; 2 65–2 56, m, 1H
(50% 2H), (H 120)2. 13C n.m.r. (50 MHz, CDCl3) 208 71,
C 3; 168 27, C=O; 143 38, 143 24, 141 23, 140 71, C 40a,
C 80a, C 90a, C 100a; 126 41, 126 35, 126 33, 126 30, 124 05,
123 82, 123 81, 123 60, C 10–80; 104 02, C 110; 90 08, C 2;
49 73, 44 13, C 90, C 100; 33 49 (low intensity), C 120. Mass
spectrum, m/z 278, 277, 276 (M, 1 4%), 275, 274 (abundance
ratios, 4 : 11 : 30 : 23 : 33), 178 (100).
from methanol to yield the title ester (5 2 g, 42%), m.p.
1
115–116 .
1708 cm
(C=O). 1H n.m.r.
(200 MHz,
max
CDCl3) 7 33–7 14, m, 4H, 7 14–7 02, m, 4H, aromatic; 4 66,
d, J 2 9 Hz, H 10; 4 32, s, H 9; 3 59, s, 0 45H (85% 2H),
OCH3; 2 93–2 88, m, 0 35H (65% 2H), H 11; 2 20–1 98, m,
1H (50% 2H), H 12. 13C n.m.r. (50 MHz, CDCl3) 178 78,
C=O; 143 71, 143 64, 142 31, 139 66, C 4a, C 8a, C 9a, C 10a;
126 28, 126 21, 125 78 (2C), 125 01, 123 66, 123 51, 123 19,
C 1–8; 51 91 (low intensity), OCH3; 46 77 (low intensity),
C 11; 43 99, 43 77, C 9, C 10; 33 20 (low intensity), C 12.
Mass spectrum, m/z 268, 267 (2 5%, C18H132H3O2), 266, 265,
264 (abundance ratio 3 : 17 : 9 : 5 : 13), 178 (100).
3-([12 0,12 0-2H2]-9 0,10 0-Dihydro-9 0,10 0-ethanoanthracen-
11 0-ylidene)prop-2-enoyl Chloride (8)
The deuterated acid (7) (20 mg) was converted by the method
previously described into the title acid chloride (8) which was
obtained as a yellow powder (21 mg, 98%), m.p. 160–161
[11,12,12-2H3]-9,10-Dihydro-9,10-ethanoanthracene-11-
carboxylic Acid
(Found: m/z, 294 078 0 001. C19H112H235ClO requires m/z,
The deuterium-labelled ester (5 0 g, 19 0 mmol) was hydrol-
ysed with aqueous ethanolic potassium hydroxide. The acidic
product was recrystallized from diethyl ether/light petroleum
to give the title acid as colourless crystals (2 5 g, 53%),
m.p. 188–190 (Found: m/z, 253 119 0 003. C17H112H3O2
1
294 077).
(Nujol) 1952 (C=C=C), 1755 cm
(C=O).
max
1H n.m.r. (200 MHz, CDCl3) 7 39–7 20, m, 4H, 7 19–7 11,
m, 4H, aromatic; 5 83, m, H 2; 5 00, s, H 100; 4 53, m, H 90;
2 73–2 69, m, 1H (50% 2H), (H 120)2. 13C n.m.r. (50 MHz,
CDCl3) 214 26, C 3; 165 89, C=O; 143 18, 143 02, 139 94,
139 51, C 40a, C 80a, C 90a, C 100a; 126 78, 126 72, 126 56,
126 50, 124 13, 123 87, 123 85, 123 70, C 10–80; 106 92, C 110;
96 37, C 2; 49 52, 43 84, C 90, C 100; 34 15 (low intensity),
C 120. Mass spectrum, m/z 297, 296, 295, 294 (M, 2 2%), 293,
292 (abundance ratio 3 : 7 : 9 : 24 : 12 : 18), 178 (100).
requires m/z, 253 118).
1
(Nujol) 3300–3000 (OH), 1700
max
(C=O). 1H n.m.r. (200 MHz, CDCl3) 7 33–7 23, m,
cm
4H, 7 16–7 04, m, 4H, aromatic; 4 66, s, H 10; 4 33, s, H 9;
2 90–2 88, m, 0 47H (53% 2H), H 11; 2 11–1 97, m, 1H (50%
2H), (H 12)2. 13C n.m.r. (50 MHz, CDCl3) 174 85, C=O;
142 43 (2C), 139 30, C 4a, C 8a, C 9a, C 10a (three detected);

668
P. Arena et al.
Pentatetraenone: Pyrolysis of Acid Chlorides (4), (5) and (8)
in ethanol-free chloroform (40 ml) under an atmosphere of
nitrogen. The mixture was then heated under re ux for a
further 2 5 h, cooled and evaporated under vacuum without
heating. The residue was separated by ash chromatography
(SiO2; dichloromethane) to yield rst the title mixture of E
and Z esters (10) (286 mg, 12%) as a yellow oil (Found: m/z,
The deposition line was evacuated and the furnace heated
to 400 for 4 h. The requisite allenic acid chloride (20–50 mg)
was prepared in a glass vial and introduced into the line. The
system was evacuated to 0 04 mmHg, the furnace heated to
the required temperature and the CsI plate cooled to c. 10 K.
The precursor was sublimed at 120–170 in a stream of argon
and pyrolysed at 550–750 /0 025 mmHg and the pyrolysate
deposited on the plate during 50 min. The infrared spectrum
was recorded.
302 130 0 003.
1960s (C=C=C), 1810w, 1716s cm
C21H18O2 requires m/z, 302 130).
max
(C=O). 1H n.m.r. (200
1
MHz, CDCl3) 7 35–7 23, m, 7 18–7 02, m, H 10–80; 5 67, d,
J 4 1 Hz, 5 60, d, J 3 7 Hz, H 2; 4 84, s, H 100; 4 13, d, J
2 0 Hz, H 90; 3 63, s, 3 58, s, OCH3; 3 22–2 77, m, H 120;
0 92, d, J 6 9 Hz, 0 90, d, J 6 9 Hz, CH3. 13C n.m.r.
(50 MHz, CDCl3) 209 69, 209 36, C 3; 166 57, 166 39, C=O;
144 07, 141 60, 140 62, 140 57, 140 53, 140 21 (2C), 139 95,
C 40a, C 80a, C 90a, C 100a; 126 50, 126 41, 126 35, 126 27
(2C), 126 18, 126 09, 126 05, 125 84, 125 68, 124 01, 123 68,
123 64, 123 51, 123 47, 123 21, C 10–80; 110 88, 110 74, C 110;
90 32, 90 22, C 2; 51 75, 51 01, OCH3; 49 79, 49 69, C 90,
C 100; 39 70, 38 98, C 120; 19 78, CH3. Mass spectrum, m/z
302 (M, 2%), 243 (8), 228 (8), 226 (10), 178 (100).
H2C5O, precursor (4) (650 ).
3756 6m, 3723 5m,
max
3711 1w, 3326 4s(br), 2925 5m, 2345 1s, 2340 3s, 2339 1
(CO2), 2207 7s (C=C=C=O), 2149 4s, 2139 8 (CO), 1862 1m,
1781 5s, 1623 7s, 1607 8s, 1471 8m, 1269 7s, 1260 0s,
1107 0m, 914 3s, 908 9m, 878 1w, 837 4s, 836 4s, 835 4s,
1
754 2m, 711 4m cm
1
. At 550 no band was detected at
. At 750 the intensity of the band at 2207 7
2707 7 cm
1
cm
was very weak.
H2C413CO, precursor (5) (650 ).
3756 8m, 2880 0s,
max
2869 6s, 2863 3s, 2815 4s, 2787 0s, 2347 0s, 2345 0s, 2340 2s,
2339 1s (CO2), 2279 5s, 2274 7s, 2273 7s (13CO2), 2207 4s
(C=C=C=O), 2168 5s (C=C=13C=O), 2154 3s, 2138 3s (CO),
2091 2w, 1787 5s, 1742 6s, 1626 5w, 1589 9w, 1450 2m,
The second compound isolated was methyl (E)-3-(120-methyl-
90,100 -dihydro-90 ,100 -ethanoanthracen-110 -yl)-3-oxo-2-tri-
phenylphosphoranylidenepropanoate (11), obtained as colour-
less crystals, m.p. 236–238 (Found: m/z, 580 215 0 006.
1440 2m, 1317 7m, 1189 2s, 1168 6m, 1149 8m, 1116 3m,
C39H33O3P requires m/z, 580 217).
cm
1664 (C=O), 1557
max
1
1101 8w, 959 0m, 880 5s, 767 0s, 731 5s cm
D2C5O, precursor (8) (650 ).
.
3064 8w, 2888 5w,
1
.
31P n.m.r. (120 MHz, CDCl3) 19 46, Ph3P=C. 1H
max
n.m.r. (200 MHz, CDCl3) 7 62–7 28, m, 3 phenyl; 7 25–
6 90, m, H 10–80; 4 82, d, J 1 9 Hz, H 90; 3 90, d, J 2 0 Hz,
H 100; 3 31, dd, J 5 6, 2 0, H 110; 3 27, s, OCH3; 2 66–2 51,
2868 6m, 2862 5s, 2843 6w, 2809 8s, 2786 1s, 2344 8s, 2340 3s
(CO2), 2207 0s (C=C=O), 2153 7s, 2138 3s (CO), 2072 3w,
1
2036 3w, 2013 5w, 1601 6w, 1318 0w, 880 7s, 729 9s cm
.
m, H 120; 0 74, d, J 6 9 Hz, CH3. 13C n.m.r.
(50 MHz,
1
At 750 no band was detected at 2207 7 cm
.
CDCl3) 195 19, 195 13, C=O; 167 89, 167 58, C=O; 145 37,
144 33, 141 95, 139 90, C 40a, C 80a, C 90a, C 100a; 133 15,
132 95, 131 36, 131 30, 128 39, 128 14, 125 65, 125 54,
125 36, 124 95, 124 62, 124 56, 123 08, 122 98, C 10–80 and
phenyl CH; 127 84, 125 98, phenyl quat. C; 56 23, 56 09,
OCH3; 51 35, 49 78, 49 76, 49 73, C 90, C 100; 34 22, 34 19,
C 120; 20 88, CH3. Mass spectrum, m/z 580 (M, 8%), 362
(24), 361 (96), 293 (27), 262 (100), 183 (38), 178 (66).
trans-12-Methyl-9,10-dihydro-9,10-ethanoanthracene-11-
carbonyl Chloride (9)
trans -12-Methyl-9,10-dihydro-9,10-ethanoanthracene-11-
carboxylic acid was prepared in 20% yield from anthracene
(10 g), but-2-enoic acid (3 87 g) and hydroquinone (0 3 g)
dissolved in benzene (35 ml) and heated at 200 for 20 h.
It crystallized from heptane, m.p. 195–196 (lit.17 191–193,
(E)- and (Z)-3-(12 0-Methyl-9 0,10 0-dihydro-9 0,10 0-
ethanoanthracen-11 0-ylidene)prop-2-enoic Acid (12)
lit.18 115 ). The 1H n.m.r. spectrum was the same as that
18
described by Ripoll et al.
(200 MHz, CDCl3) 7 29–7 21,
m, 7 15–7 04, m, H 1–8; 4 54, d, J 2 2 Hz, 3 97, d, J 2 2 Hz,
H 9, H 10; 2 34–2 15, m, H 11, H 12; 0 91, d, J 6 7 Hz, CH3.
13C n.m.r. (50 MHz, CDCl3) 179 83, C=O; 144 61, 142 22,
140 93, 139 28, C 4a, C 8a, C 9a, C 10a; 126 10, 125 95 (2C),
125 75, 125 69, 125 33, 123 24, 123 00, C 1–8; 52 54, 50 79,
C 9, C 10; 46 48, C 11; 37 52, C 12; 21 07, CCH3. Mass
spectrum, m/z 264 (M, 4%), 178 (100).
A solution of the acid (2 2 g, 8 3 mmol) in dichloromethane
(10 ml) under an atmosphere of nitrogen was treated with
oxalyl chloride (2 18 ml, 25 mmol) and the mixture was allowed
to stand for 2 h. The excess of reagent and solvent were
The ester (10) (250 mg, 0 83 mmol) was added to lithium
hydroxide monohydrate (65 mg, 2 5 mmol), water (4 ml) and
1,2-dimethoxyethane (4 ml) and the resulting mixture stirred
at room temperature for 30 h. The alkaline solution was
diluted with water and extracted with ether, separated, and
the aqueous phase was ltered and acidi ed with concentrated
hydrochloric acid to pH 1. After 2 days the colourless crystalline
precipitate was collected, washed with water and dried to give
the title acid (12) (137 mg, 57%), m.p. 151–152 (Found: m/z,
288 116 0 006. C20H16O2 requires m/z, 288 115).
(C=C=C), 1698 cm
1957
max
(C=O). 1H n.m.r. (200 MHz, CDCl3)
1
7 38–7 21, m, 7 19–7 05, m, H 10–80; 5 1, d, J 4 1 Hz, 5 0,
d, J 3 7 Hz, H 2; 4 85, s, H 100; 4 10, br s, H 90; 2 92–2 81,
m, H 120; 0 92, d, J 6 9 Hz, 0 90, d, J 6 9 Hz, CH3. 13C
n.m.r. (50 MHz, CDCl3) 210 85, 210 75, C 3; 170 87, 170 61,
C=O; 144 11, 144 00, 140 65, 140 34, 139 95, 139 71, C 40a,
C 80a, C 90a, C 100a; 126 69, 126 49, 126 41, 126 21, 125 88,
125 71, 124 03, 123 74, 123 70, 123 56, 123 51, 123 29, C 10–
80; 111 29, C 110; 90 04, 89 97, C 2; 51 82, 51 00, 49 70,
49 59, C 90, C 100; 39 95, 39 23, C 120; 19 82, 19 63, ?; 15 26,
CH3. Mass spectrum, m/z 288 (M, 1%), 178 (100).
evaporated and the acid chloride (9) was obtained quantitatively
1
as a colourless oil.
1798 (C=O) cm
.
1H n.m.r. (200
max
MHz, CDCl3) 7 35–7 20, m, 7 18–7 05, m, H 1–8; 4 73, d,
J 2 2 Hz, H 10; 4 03, d, J 2 3 Hz, H 9; 2 68, dd, J 5 4,
2 2 Hz, H 11; 2 50–2 35, m, H 12; 0 98, d, J 6 9 Hz, CH3.
13C n.m.r. (50 MHz, CDCl3) 175 00, C=O; 144 00, 141 11,
140 90, 138 37, C 4a, C 8a, C 9a, C 10a; 126 77, 126 57,
126 41, 126 22, 125 99, 125 51, 123 80, 123 48, C 1–8; 64 46,
C 11; 50 81, 47 35, C 9, C 10; 38 53, C 12; 21 11, CH3. Mass
spectrum, m/z 282 (M, 0 03%), 178 (100).
Methyl (E)- and (Z)-3-(12 0-Methyl-9 0,10 0-dihydro-9 0,10 0-
ethanoanthracen-11 0-ylidene)prop-2-enoate (10)
(E)- and (Z)-3-(12 0-Methyl-9 0,10 0-dihydro-9 0,10 0-
ethanoanthracen-11 0-ylidene)prop-2-enoyl Chloride (13)
A solution of methyl (triphenylphosphoranylidene)ethanoate
(3 0 g, 9 2 mmol) and triethylamine (1 3 ml, 9 2 mmol) in
ethanol-free chloroform (10 ml) was added dropwise to a
boiling solution of the acid chloride (9) (2 2 g, 7 8 mmol)
The acid (12) (60 mg, 0 20 mmol) in dichloromethane (2
ml) was treated with oxalyl chloride (0 8 ml, 0 80 mmol)
and allowed to stand for 2 h at room temperature under an
atmosphere of nitrogen. The excess of reagent and solvent

Precursors of Pentatetraenones
669
were evaporated under vacuum without heating. The title acid
the mixture was stirred until all the material had dissolved.
Hydrochloric acid (1 M) was then added dropwise until no more
material precipitated. The colourless precipitate was collected,
washed with water and dried to give the title formyl acid (18)
(220 mg, 76%), m.p. 185–187 (Found: m/z, 278 095 0 002.
chloride (13) (62 mg, 98%) was obtained as a yellow oil.
max
1
1952 (C=C=C), 1751 (C=O) cm
.
1H n.m.r. (200 MHz,
CDCl3) 7 36–7 30, m, 7 23–7 14, m, H 10–80; 5 90, d, J 3 6
Hz, 5 84, d, J 3 5 Hz, H 2; 4 95, s, H 100; 4 21, br s, H 90;
3 02–2 96, m, H 120; 1 00, d, J 6 9 Hz, 0 95, d, J 6 9 Hz, CH3.
C18H14O3 requires m/z, 278 094).
1735 (HC=O), 1698 cm
(Nujol) 2728 (CHO),
max
13C n.m.r.
(50 MHz, CDCl3) 214 82, C 3; 165 70, C=O;
(C=O). 1H n.m.r.
(200 MHz,
1
143 79, 143 62, 140 42, 140 23, 139 22, 139 00, 138 71, C 40a,
C 80a, C 90a, C 100a; 126 48, 126 43, 126 25, 126 17, 125 73,
125 57, 123 91, 123 69, 123 63, 123 54, 123 37, 123 27, C 10–
80; 112 26, C 110; 97 02, C 2; 50 72, 50 67, 49 42, 49 38, C 90,
C 100; 40 60, 39 92, C 120; 19 57, 19 25, CH3.
CDCl3) 9 61, s, CHO; 8 7–7 6, br s, OH (D2O exchange);
7 37–7 23, m, 4H, 7 18–7 07, m, 4H, H 1–8; 4 78, d, J 2 5
Hz, H 9 (H 10); 4 75, d, J 2 5 Hz, H 10 (H 9); 3 39, dd, J 5 1,
2 5 Hz, H 12; 3 28, dd, J 5 1, 2 5 Hz, H 11. 13C n.m.r. (50
MHz, CDCl3) 199 62, CHO; 177 56, C=O; 142 09, 141 92,
140 59, 139 60, C 4a, C 8a, C 9a, C 10a; 126 86, 126 66,
126 59, 125 26, 125 04, 124 27, 123 79, 123 53, C 1–8; 55 31,
C 12; 46 21, C 11; 45 18, 44 62, C 9, C 10. Mass spectrum,
m/z 278 (M, 2%), 178 (100).
Pyrolysis of the Acid Chloride (13)
The deposition line was evacuated and the furnace heated
to 400 for 16 h. The mixture of (E)- and (Z)-prop-2-enoyl
chlorides (13) (60 mg, 0 20 mmol) was introduced into the line
in a glass vial and the system was evacuated to 0 03 mmHg,
the furnace heated to 650 and the CsI plate cooled to c. 10 K.
The precursor was sublimed at 60–80 in a ow of argon (0 05
mmHg) and the precursor/argon mixture pyrolysed at 650 /0 02
mmHg and deposited during 45 min. The infrared spectrum was
Methyl trans-12-Formyl-9,10-dihydro-9,10-
ethanoanthracene-11-carboxylate (19)
The formyl acid (18) (2 3 g, 8 3 mmol) was dissolved in
tetrahydrofuran (50 ml) and excess of ethereal diazomethane
was added. The excess of diazomethane was quenched with
acetic acid and the solvent was evaporated to yield an orange oil.
Puri cation by ash chromatography (Al2O3; ethyl acetate/light
petroleum, 1 : 4) gave the title ester (19) as an orange oil (2 0 g,
recorded (4000–650 cm 1).
3323 1w, 3064 5w, 2888 1w,
max
2869 6w, 2852 9w, 2815 1m, 2783 4s, 2340 9s, 2205 1m,
2154 2s, 2149 2s, 2138 5s, 2091 3m, 1974 6w, 1947w, 1815 5m,
1
1318 0m, 878 6s, 837 7s, 755 5s, 728 7s cm
.
83%) (Found: m/z, 292 110 0 003. C19H16O3 requires m/z,
1
292 110).
2722m (CHO), 1731 cm
(C=O). 1H n.m.r.
9,10,11,15-Tetrahydro-9,10[3 0,4 0]-furanoanthracene-12,14-
dione (16)
max
(200 MHz, CDCl3 (base-washed)) 9 62, s, CHO; 7 37–7 23,
m, 4H, 7 18–7 07, m, H 1–8; 4 77, m, H 9, H 10; 3 62, s,
OCH3; 3 36, m, H 11, H 12. 13C n.m.r. (50 MHz, CDCl3
(base-washed)) 199 70, CHO; 172 58, C=O; 142 12, 141 83,
140 80, 139 68, C 4a, C 8a, C 9a, C 10a; 126 70, 126 53,
126 48, 126 44, 124 86, 124 38, 123 87, 123 49, C 1–8; 55 36,
C 12; 52 34, OCH3; 46 44, C 11; 454 23, 45 62, C 9, C 10.
Mass spectrum, m/z 292 (M, 1%), 178 (100).
The crude anhydride was prepared by the method of Bach-
mann and Scott19 and recrystallized from ethyl acetate/acetic
anhydride (9 : 1) by using a Soxhlet apparatus to give the
anhydride (16) (97% yield), m.p. 264–265 (lit.19 264–264 5 ).
1
1862, 1781 cm
. Mass spectrum, m/z 276 (5%, M),
max
178 (100).
Reaction of the anhydride with methanol in the presence
of sulfuric acid gave the cis dimethyl ester (90% yield), m.p.
1
149–150 (lit.19 150–151 ).
spectrum, m/z 322 (M, 2%), 178 (100).
1748 cm
(C=O). Mass
Methyl trans-12-Ethenyl-9,10-dihydro-9,10-
ethanoanthracene-11-carboxylate (20)
max
n-Butyllithium (1 8 M in hexane, 9 45 ml, 17 01 mmol)
was added dropwise from an airtight syringe during 10 min
to a stirred suspension of methyltriphenylphosphonium bro-
mide (6 2 g, 17 mmol) in dry diethyl ether (20 ml) under
an atmosphere of nitrogen at 78 . The mixture was then
allowed to stir at room temperature for 3 h. The resulting
phosphorane solution was cooled to 78 and a solution of
the formyl ester (19) (4 32 g, 14 5 mmol) in dry diethyl ether
(10 ml) was added slowly. The yellow reaction mixture was
warmed to 40 and when it changed to an o -white colour
(c. 5 min) it was cooled to 50 and stirred for 1 h before
being allowed to warm to room temperature over a 2-h period.
It was then stirred at room temperature for a further 16 h.
The white slurry which resulted was quenched with water
(25 ml) and the ethereal layer was separated. The aqueous
layer was extracted with dichloromethane (3 100 ml) and the
extracts and ethereal solution were combined, dried (Na2SO4)
and evaporated. The resulting brown oil was puri ed by ash
chromatography (SiO2; dichloromethane/light petroleum, 2 : 1)
14-Hydroxy-9,10,14,15-tetrahydro-9,10[3 0,4 0]-
furanoanthracene-12(11 H)-one (17)
Disodium tetracarbonylferrate sesquidioxanate (c. 21 mmol)
was prepared by the method of Finke and Sorrell,13 washed
repeatedly with dry hexane and suspended in anhydrous
tetrahydrofuran (120 ml) under an atmosphere of nitrogen.
The anhydride (16) (5 6 g, 20 mmol) was added directly to the
suspension and the mixture was stirred for 2 h. The reaction
mixture was then acidi ed with hydrochloric acid (4 M, 150
ml) and stirred for 30 min. The mixture was concentrated
under vacuum to remove most of the tetrahydrofuran and then
extracted with ether until the aqueous phase was no longer
red. The ethereal extracts were combined, dried (Na2SO4) and
evaporated to give a red-brown residue. The residue was washed
with a small amount of chloroform and the solid collected.
Recrystallization from chloroform/diethyl ether yielded the title
lactol (17) (4 89 g, 88%) as a colourless powder, m.p. 246
(lit.20 246 ).
(Nujol) 3295 (OH), 1734 cm (C=O). The
1
max
1H n.m.r. spectrum was as previously described.18 13C n.m.r
(50 MHz, CDCl3) 175 162, C=O; 142 61, 141 72, 140 36,
139 56, C 4a, C 8a, C 9a, C 10a; 126 49, 126 37, 126 20, 126 03,
125 23, 124 60, 124 17, 123 82, C 1–8; 100 59, C 14; 49 02,
C 11; 47 30, C 15; 44 74, 44 64, C 9, C 10. Mass spectrum,
m/z 278 (M, 5%), 178 (100).
to give the title ester (20) as a colourless viscous oil (3 00 g,
1
72%).
3072, 3023, 2951, 1735 cm
(C=O). 1H n.m.r.
max
(200 MHz, CDCl3) 7 34–7 24, m, 4H, 7 15–7 07, 4H, H 1–8;
5 43–5 25, m, =CH–; 5 13–4 91, m, =CH2; 4 64, d, J 2 4
Hz, H 9; 4 16, d, J 2 4 Hz, H 10; 3 61, s, OCH3; 3 04–2 95,
m, H 12; 2 53, dd, J 5 3, 2 4 Hz, H 11. 13C n.m.r. (50 MHz,
CDCl3) 173 18, C=O; 143 57, 142 35, 142 32, 140 68, C 4a,
C 8a, C 9a, C 10a; 140 54, =CH–; 126 15, 125 96, 125 94,
125 83, 125 29, 124 79, 123 28, 123 19, C 1–8; 115 44, =CH2;
51 82, OCH3; 51 04, C 11; 49 91, C 12; 46 85, 46 56, C 9,
C 10. Mass spectrum, M not observed, m/z 178 (100%).
trans-12-Formyl-9,10-dihydro-9,10-ethanoanthracene-11-
carboxylic Acid (18)
The lactol (17) (290 mg, 1 0 mmol) was dissolved in aque-
ous potassium hydroxide (10%) until the pH was >11 and

670
P. Arena et al.
trans-12-Ethenyl-9,10-dihydro-9,10-ethanoanthracene-11-
carboxylic Acid (21)
210 59, 210 22, C 3; 166 36, 166 32, C=O; 143 19, 143 12,
140 64, 140 59, 140 38, 140 32, C 4a0, C 8a0, C 9a0, C 10a0;
137 95, 137 70, ethenyl =CH–; 126 61, 126 54, 126 51,
126 47, 126 24, 126 17, 125 55, 125 42, 124 00, 123 79,
123 70, 123 66, 123 57, 123 35, C 10–80; 116 16, ethenyl =CH2;
108 52, 107 82, C 110; 90 38, 90 10, C 2; 51 82, 51 72, OCH3;
50 54, 50 34, 49 70, 49 60, C 90, C 100; 49 15, 48 68, C 120.
Mass spectrum, m/z 314 (M, 5%), 178 (100). The second was
methyl 3-(12 0-ethenyl-9 0,10 0-dihydro-9 0,10 0-ethanoanthracene-
11 0 -yl)-3-oxo-2-triphenylphosphoranylidenepropanoate (24),
which was obtained as a yellow powder (240 mg, 40%),
The ester (20) (2 70 g, 9 3 mmol) was hydrolysed in a mix-
ture of water (10 ml), ethanol (60 ml) and potassium hydroxide
(2 0 g) by heating under re ux for 20 h. The hot solution
was ltered, cooled and acidi ed to pH 2 with hydrochloric
acid (4 M) and the white precipitate was collected and washed
with water. Recrystallization from aqueous ethanol gave the
monohydrate of the title acid (21) as nearly colourless crystals,
m.p. 210–212 (Found: C, 77 9; H, 5 6. C19H16O2.H2O
requires C, 77 5; H, 6 2%). The acid was sublimed six times
at 180 /0 04 mmHg to give colourless crystals (Found: C,
m.p. 114–116 (Found: m/z, 592 214 0 003. C40H33O3P
1
requires m/z, 592 215).
1662 cm
(C=O). 1H n.m.r.
max
82 5; H, 5 9.
C19H16O2 requires C, 82 6; H, 5 8%).
max
(200 MHz, CDCl3) 7 63–7 32, m, phenyl H; 7 27–6 91,
m, H 10–80; 5 44–5 26, m, ethenyl =CH–; 4 92–4 78, H 100,
=CH2; 4 07, d, J 2 2 Hz, H 90; 3 66, dd, J 5 7, 2 2 Hz,
H 110; 3 27, s, OCH3; 3 26–3 18, m, H 120. 13C n.m.r.
(50 MHz, CDCl3) 194 36, 194 30, C 3=O; 167 90, 167 49,
C 1=O; 144 55, 144 46, 141 46, 140 04, C 4a0, C 8a0, C 9a0,
C 10a0; 142 48, ethenyl =CH–; 133 24, 133 05, 131 39, 131 33,
128 34, 128 09, 3 phenyl CH; 127 68, 125 82, phenyl quat.;
125 79, 125 66, 125 11, 124 99, 124 81, 124 58, 123 16,
123 05, C 10–80; 113 77, =CH2; 54 39, 54 25, OCH3; 50 28,
C 110; 49 76, 49 36, C 90, C 100; 44 56, 44 53, C 120. Mass
spectrum, m/z 592 (M, 5%), 361 (20), 262 (45), 183 (20), 178
(100).
(hydrate) 3448s(br) (OH), 1702 cm (C=O). 1H n.m.r. (200
MHz, CDCl3) 7 43–7 23, m, 4H, 7 17–7 08, m, 4H, H 1–8;
5 43–5 24, m, =CH–; 5 13–4 92, m, =CH2; 4 64, d, J 2 3
Hz, H 10; 4 25, d, J 2 3 Hz, C 9; 2 96, sept., H 12; 2 54, dd,
J 5 5, 2 3 Hz, H 11. 13C n.m.r. (50 MHz, CDCl3) 178 00,
C=O; 143 67, 142 28, 140 60, 139 45, C 4a, C 8a, C 9a, C 10a;
140 36, =CH–; 126 26, 126 06 (2C), 125 90, 125 39, 125 16,
123 35, 123 18, C 1–8; 115 67, =CH2; 50 93, C 11; 49 97,
C 12; 46 59 (2C), C 9, C 10. Mass spectrum, M not observed,
m/z 178 (100%).
1
trans-12-Ethenyl-9,10-dihydro-9,10-ethanoanthracene-11-
carbonyl Chloride (22)
The ester (23) (130 mg, 0 41 mmol) was added to a solution
of lithium hydroxide monohydrate (46 mg, 20 mmol) in water
(1 85 ml) and 1,2-dimethoxyethane (1 85 ml) and the mixture
was stirred for 20 h. Ether (3 ml) and water (3 ml) were then
added and the ethereal layer was separated, dried (MgSO4) and
evaporated to yield unreacted ester (20 mg, 15%). The aqueous
phase was acidi ed with hydrochloric acid (50 ml, 10%) to pH
1 and extracted with ether (3 30 ml). The ether extracts were
combined, washed with water, dried (MgSO4) and evaporated
under vacuum to give the crude acid (70 mg, 56%) as a yellow
oil which crystallized on standing. The product was puri ed
by ash chromatography (SiO2; dichloromethane followed by
ethyl acetate) to give the title acid (25) as pale yellow crystals,
A
solution of the acid (21) (25 mg, 0 09 mmol) in
dichloromethane (10 ml) under an atmosphere of nitrogen was
treated with oxalyl chloride (13 mg, 0 01 mmol) and the
mixture was allowed to stand at room temperature for 2 h.
The volatile constituents were evaporated under vacuum and
the acid chloride (22) was obtained as a pale yellow oil in
quantitative yield (Found: m/z, 294 081 0 003. C19H1535ClO
requires m/z, 294 081).
(200 MHz, CDCl3) 7 36–7 24, 4H, 7 18–7 11, 4H, H 1–8;
5 38–5 20, =CH–; 5 20–4 96, =CH2; 4 83, d, J 2 0 Hz, C 10;
4 18, d, J 2 1 Hz, C 9; 3 07–2 93, m, H 11, H 12. 13C n.m.r.
(50 MHz, CDCl3) 173 85, C=O; 143 08, 140 96, 140 62,
138 32, C 4a, C 8a, C 9a, C 10a; 139 19, =CH–; 126 80, 126 56,
126 39, 126 30, 126 19, 125 23, 123 72, 123 48, C 1–8; 116 78,
=CH2; 62 91, C 11; 50 04, C 12; 47 39, 47 20, C 9, C 10. Mass
spectrum, m/z 294 (M, 2%), 178 (100).
1
1794 cm
(C=O). 1H n.m.r.
max
m.p. 168–172 .
cm
3449br (OH), 1962 (C=C=C), 1702
max
(C=O). 1H n.m.r. (200 MHz, CDCl3) 10 0, br s, OH;
1
7 36–7 19, m, 7 18–7 09, m, H 10–80; 5 61–5 54, m, ethenyl
=CH–; 5 45–4 92, m, =CH2, H 2; 4 90, s, H 100; 4 29, d, J
2 3 Hz, H 90; 3 49–3 38, m, H 120. 13C n.m.r.
(50 MHz,
Mixture of E- and Z-Isomers of 3-(12 0-Ethenyl-9 0,10 0-
dihydro-9 0,10 0-ethanoanthracen-11 0-ylidene)prop-2-enoic
Acid (25)
CDCl3) 212 02, 211 81, C 3; 171 88, 171 54, C=O; 143 33,
143 18, 140 62, 140 53, 140 37, 140 18, 140 16, C 4a0, C 8a0,
C 9a0, C 10a0; 137 90, 137 71, ethenyl =CH–; 126 89, 126 73,
126 66, 126 58, 126 42, 126 21, 125 71, 125 56, 124 18,
123 95, 123 88, 123 77, 123 52, C 10–80; 116 50, 116 45,
=CH2; 109 01, 108 25, C 110; 90 42, 90 15, C 2; 50 66, 50 44,
49 67, 49 58, C 90, C 100; 49 50, 48 99, C 120. Mass spectrum,
m/z 300 (M, 4%), 178 (100).
A solution of methyl (triphenylphosphoranylidene)ethanoate
(0 64 g, 1 9 mmol) and triethylamine (0 26 ml, 1 9 mmol) in
ethanol-free chloroform was added dropwise to a boiling solution
of the acid chloride (22) (266 mg, 1 0 mmol) in ethanol-free
chloroform (12 ml) under an atmosphere of nitrogen. When all
the solution had been added, heating was continued for 5 h after
which the mixture was cooled and the solvent was evaporated
under vacuum to give a red residue. Water was added and the
mixture was extracted with ether (3 20 ml). A solid (triph-
enylphosphine oxide) which precipitated from the aqueous phase
was collected and washed with ether. The ethereal extracts and
washings were combined, washed with water, dried (MgSO4)
and evaporated to give a mixture of oil and crystals. Flash chro-
matography (SiO2; ethyl acetate/light petroleum, 1 : 1) yielded
two products. The rst was a mixture of the E- and Z-isomers
of methyl 3-(120-ethenyl-90,100-dihydro-90,100-ethanoanthracen-
Mixture of E- and Z-Isomers of 3-(12 0-Ethenyl-9 0,10 0-
dihydro-9 0,10 0-ethanoanthracen-11 0-ylidene)prop-2-enoyl
Chloride (26)
The acid (25) (20 mg, 0 06 mmol) was dissolved in
dichloromethane (0 2 ml) and oxalyl chloride (0 02 ml, 0 2
mmol) was added under an atmosphere of nitrogen. The
mixture was allowed to stand for 2 h and then the solvent
and excess of reagent were evaporated under vacuum at 0 to
give the title acid chloride (26) as a yellow oil (Found: m/z,
318 081 0 003. C21H1535ClO requires m/z, 318 081).
1955 (C=C=C), 1772, 1750 cm
max
110-ylidene)prop-2-enoate (23) obtained as a yellow oil (120
(C=O). 1H n.m.r.
(200
1
1
mg, 43%).
1963 (C=C=C), 1718 cm (C=O). 1H n.m.r.
MHz, CDCl3) 7 43–7 29, m, 7 24–7 08, m, H 10–80; 5 89–5 82,
m, ethenyl =CH–; 5 39–4 94, m, =CH2, H 2, H 100; 4 35,
apparent t, J 2 1 Hz, H 90; 3 55–3 40, m, H 120. 13C n.m.r.
(50 MHz, CDCl3) 215 72, 215 65, C 3; 165 54, 165 31, C=O;
143 00, 142 76, 140 22, 139 96, 139 42, 139 25, 139 09, C 4a0,
max
(200 MHz, CDCl3) 7 43–7 22, m, 7 20–7 04, m, H 10–80;
5 67–5 59, m, ethenyl =CH–; 5 41–4 94, m, =CH2, H 2; 4 89,
s, H 100; 4 29, d, J 2 4 Hz, H 90; 3 62, 3 59, 2s (c. 1 : 1),
2
OCH3; 3 48–3 38, m, H 120. 13C n.m.r. (50 MHz, CDCl3)

Precursors of Pentatetraenones
671
C 8a0, C 9a0, C 10a0; 137 14, 137 077, ethenyl =CH–; 126 67,
126 61, 126 54, 126 44, 126 23, 126 14, 125 50, 125 36,
125 07, 123 99, 123 81, 123 73, 123 60, 123 44, 123 32, C 10–
80; 116 67, 116 54, =CH2; 110 58, 110 22, C 110; 97 19, 97 11,
C 2; 50 36, 50 30, 50 09, 49 88, 49 50, 49 28, 49 21, C 90,
C 100; 47 23, 47 04, C 120. Mass spectrum, m/z 320 (0 5%),
318 (M, 1 5), 178 (100).
C 120. Mass spectrum, m/z 301 (M, 1 5%), 300 (1 3), 178
(100).
Mixture of E- and Z-Isomers of 3-(12 0-Ethenyl-9 0,10 0-
dihydro-9 0,10 0-ethanoanthracen-11 0-ylidene)[1-13C]prop-
2-enoyl Chloride (27)
The title acid chloride (27) was prepared as previously
described and obtained as
a yellow oil (Found: m/z,
Mixture of E- and Z-Isomers of 3-(12 0-Ethenyl-9 0,10 0-
dihydro-9 0,10 0-ethanoanthracen-11 0-ylidene)[1-13C]prop-
2-enoic Acid
Methyl (triphenylphosphoranylidene)[1-13C]ethanoate (1 5
g, 4 0 mmol, 50 atom % 13C) was allowed to react with
the acid chloride (22) (530 mg, 2 0 mmol) under the condi-
tions described for the unlabelled reagent and the products
were separated. Methyl 3-(120-ethenyl-90,100-dihydro-90,100-
ethanoanthracen-110-ylidene)[1-13C]prop-2-enoate was obtained
319 085 0 003. C2013CH1535ClO requires m/z, 319 085).
1
1961 (C=C=C), 1838, 1777 (C=O), 1738 cm
max
1H n.m.r.
(
13C=O).
(200 MHz, CDCl3) 7 43–7 29, m, 7 24–7 08,
m, H 10–80; 5 89–5 82, ethenyl =CH–; 5 35–4 95, m, ethenyl
=CH2, H 2, H 100; 4 35, apparent t, J 2 1 Hz, H 90; 3 55–
3 40, m, H 120. 13C n.m.r.
(50 MHz, CDCl3) 200 99,
C 3; 165 83, 165 61 (intense), C=O; 143 28, 143 03, 140 49,
140 23, 139 35, C 4a0, C 8a0, C 9a0, C 10a0; 137 43, 137 35,
ethenyl =CH–; 127 31, 126 95, 126 89, 126 82, 126 72,
126 51, 126 27, 125 78, 125 63, 125 52, 125 34, 125 20,
124 27, 124 01, 123 87, 123 72, 123 04, 122 54, C 10–80;
116 94, 116 81, ethenyl =CH2; 98 15, 97 46, 97 39, 96 58,
C 2; 50 64, 50 58, 50 37, 49 78, 49 55, C 90, C 100; 47 55,
46 79, C 120. Mass spectrum, m/z 319 (M, 5%), 318 (4), 276
(50), 241 (70), 240 (35), 239 (50), 178 (100).
as a yellow oil (57 mg, 12%).
1
1963 (C=C=C), 1717
max
(C=O), 1673 cm
(
13C=O). 1H n.m.r. (200 MHz, CDCl3)
7 36–7 32, m, 7 18–7 05, m, H 10–80; 5 64–5 58, m, ethenyl
=CH–; 5 45–4 89, m, =CH2, H 2; 4 88, s, H 100; 4 28, d,
J 2 3 Hz, H 90; 3 62, 3 59, 2t (intensity c. 1 : 1), 2 OCH3;
3 46–3 76, m, H 120. 13C n.m.r. (50 MHz, CDCl3) 210 76,
210 39, C 3; 166 55, 166 29 (intense), C=O; 143 33, 143 26,
140 99, 140 79, 140 73, 140 53, 140 45, C 4a0, C 8a0, C 9a0,
C 10a0; 138 09, 137 85, ethenyl =CH–; 126 76, 126 69, 126 65,
126 55, 126 38, 126 31, 125 70, 125 56, 124 17, 123 94,
123 85, 123 80, 123 73, 123 49, C 10–80; 116 32, ethenyl
=CH2; 108 622 ( anked by d, J 2 6 Hz), 107 69 ( anked by
d, J 2 6 Hz), C 110; 90 52 ( anked by d, J 40 Hz), 90 25
( anked by d, J 40 Hz), C 2; 51 98, 51 95, 51 89, 50 70,
50 49, C 90, C 100; 49 85, 49 75, 49 30, 48 82, C 120. Mass
spectrum, m/z 315 (M, 4%), 314 (3), 255 (50), 178 (100).
Methyl 3-(12 0-ethenyl-9 0,10 0-dihydro-9 0 ,10 0 -ethanoanthra-
cen-11 0-yl)-3-oxo-2-triphenylphosphoranylidene[1-13C]propa-
noate was obtained as colourless crystals (700 mg, 60%),
Pyrolysis of Acid Chlorides (26) and (27)
The deposition line was evacuated and the furnace heated
to 400 for 16 h. The requisite acid chloride (20 mg, 0 06
mmol) was introduced into the line in a glass vial and the
system was evacuated to 0 04 mmHg, the furnace heated to
the required temperature and the CsI plate cooled to c. 10
K. The precursor was sublimed at 60–180 in a ow of argon
(0 07 mmHg) and pyrolysed and deposited during 1 h. The
infrared spectrum was recorded (4000–650 cm 1, 0 5 cm
resolution).
Precursor (26) (650 /0 02 mmHg).
3635 8s, 3545 2s, 2852 4m, 2347 5s (CO2), 2327 3, 2281 9w,
2188 2w, 2138 7m (CO), 2104 3s(br), 2092 2m(br), 1764 2w,
1
3724 1s, 3698 8s,
max
m.p. 114–116 (Found: m/z, 593 221 0 006. C3913CH33O3P
1
requires m/z, 593 218).
(
1663 (C=O), 1623 cm
1620 8m, 1602 3s, 1110 0w, 1038 0w, 883 4m, 731 8s, 662 2s
max
1
13C=O). 1H n.m.r. (200 MHz, CDCl3) 7 60–7 31, 3 phenyl
cm
.
CH; 7 25–6 93, H 10–80; 5 39–5 25, ethenyl =CH–; 4 90–4 77,
ethenyl =CH2, H 100; 4 06, d, J 2 0 Hz, H 90; 3 65, dd, J
5 6, 2 0 Hz, H 110; 3 26, apparent t, OCH3; 3 23–3 16, m,
H 120. 13C n.m.r. (50 MHz, CDCl3) 194 21, 194 16, 194 11,
194 06, C 3=O; 167 64, 167 33 (intense), C 1=O; 147 75,
145 05, 144 66, 144 38, 144 28, 142 00, 141 28, 140 14,
139 87, C 4a0, C 8a0, C 9a0, C 10a0; 142 31, ethenyl =CH–;
133 06, 132 86, 131 22, 131 16, 128 17, 127 92, phenyl CH;
127 50, 125 64, phenyl quat.; 125 61, 125 48, 125 33, 124 95,
124 82, 124 65, 124 53, 124 42, 122 99, 122 87, 122 61, C 10–
80; 113 61, ethenyl =CH2; 54 20, 54 07, OCH3; 50 11, 49 59,
C 110; 49 19, 48 30, 45 99, C 90, C 100; 44 38, 44 35, C 120.
Mass spectrum, m/z 593 (M, 7%), 362 (32), 361 (25), 262
(73), 183 (38), 178 (100).
The same procedure was used for precursor (27) except that
after measurement of the infrared spectrum, the CsI plate was
warmed to room temperature and the products were analysed
by gas chromatography–mass spectrometry.
Precursor (27) (550 /0 02 mmHg).
2963 4m, 2887 9s,
max
2868 6s, 2963 1, 2853 4s, 2814 9s, 2785 5s, 2756 3s, 2345 0s
(CO2), 2340 2s (CO2), 2279 5s (13CO2), 2275 6s (13CO2),
2154 3w, 2138 5s (CO), 1779 5s, 1701 6s, 1506 6m, 1478 1m,
1455 3m, 1385 7m, 1336 7m, 1318 0m, 1262 3m, 1080 3s,
1
1067 1s, 1049 9s, 755 7s cm
. G.c.–m.s.: product A (tR
11 90 min), m/z 178 (M, 100%), 176 (20), 152 (10); product
B (tR 16 08 min), m/z 254 (M, 75%), 253 (100), 252 (40),
250 (20), 126 (14), 113 (20).
At 650 /0 02 mmHg.
2962 9w, 2927 8w, 2888 0m,
max
The ester (23) (40 mg, 0 13 mmol, 50 atom % 13C) was
hydrolysed as previously described and the title acid was
obtained as yellow crystals (25 mg, 64%, 50 atom % 13C),
2869 4s, 2963 4s, 2815 0s, 2785 9s, 2345 1s (CO2), 2339 1s
(CO2), 2279 6s (13CO2), 2273 7s (13CO2), 2154 2m, 2138 5s
(CO), 2106 6m, 2091 3s (13CO), 1256 7m, 1095 6w, 883 7m,
783 2m, 726 1m cm 1. G.c.–m.s.: product A (tR 11 89 min),
m/z 178 (M, 100%), 177 (20), 176 (55), 152 (24), 151 (22),
150 (20), 89 (55), 88 (30), 76 (40); product B (tR 16 07 min),
254 (M, 70%), 253 (100), 252 (40), 250 (20), 126 (14).
m.p. 170–172 .
(C=O), 1673 cm
3432br (OH), 1960 (C=C=C), 1700
max
1
(
13C=O). 1H n.m.r. (200 MHz, CDCl3)
7 36–7 28, m, 7 25–7 13, m, C 10–80; 5 61–5 55, m, ethenyl
=CH–; 5 44–4 92, m, ethenyl =CH2, H 2; 4 90, s, H 100; 4 30,
d, J 2 1 Hz, H 90; 3 54–3 39, m, H 120. 13C n.m.r. (50 MHz,
CDCl3) 211 81, 211 63, C 3; 171 22, 170 84 (intense), C=O;
143 20, 143 06, 140 48, 140 39, 140 24, 140 05, C 4a0, C 8a0,
C 9a0, C 10a0; 137 77, 137 58, ethenyl =CH–; 126 77, 126 61,
126 53, 126 46, 126 30, 125 58, 125 44, 124 04, 123 83,
123 76, 123 68, 123 63, 123 39, C 10–80; 116 38, 116 31,
ethenyl =CH2; 108 96, 108 91, 108 26, 108 22, C 110; 90 18
( anked by d, J 40 Hz), 89 94 ( anked by d, J 40 Hz), C 2;
50 53, 50 33, 50 03, 49 55, 49 47, C 90, C 100; 49 38, 48 87,
At 750 /0 02 mmHg.
2961 88w, 2920 4w, 2888 0s,
max
2870 6m, 2863 2s, 2815 3s, 2345 0s (CO2), 2340 2s (CO2),
2339 1s (CO2), 2279 5m (13CO2), 2273 7 (13CO2), 2154 3,
2138 4s (CO), 2106 6m, 2091 3s (13CO), 878 6m, 837 5m,
783 6m, 728 1m cm 1. G.c.–m.s.: product A (tR 11 89 min),
m/z 178 (M, 100%), 177 (30), 176 (50), 152 (30), 151 (28),
150 (25), 89 (80), 88 (54), 87 (18), 76 (65), 75 (32), 74 (15),
63 (25); product B (tR 16 04 min), m/z 254 (M, 70%), 253
(100), 252 (40), 250 (20), 126 (14).

672
P. Arena et al.
2
3
Product A was identi ed as anthracene and product B as
Brown, R. D., Godfrey, P. D., and Champion, R., J. Mol.
Spectrosc., 1987, 123, 93.
9,10-dihydro-9,10[10,20]-benzenoanthracene (triptycene).
Brown, R. D., Godfrey, P. D., Ball, M. J., Godfrey, S.,
McNaughton, D., Rodler, M., Kleibomer, B., and Champion,
R., J. Am. Chem. Soc., 1986, 108, 6534.
Brown, R. F. C., Coulston, K. J., Eastwood, F. W., Irvine,
M. J., and Pullin, A. D. E., Aust. J. Chem., 1988, 41, 225.
East, A. L. L., J. Chem. Phys., 1998, 108, 3574.
Lang, R. W., and Hansen, H.-J., Helv. Chim. Acta, 1980,
63, 438.
Masaaki, K., Uno, T., Kobayashi, M., and Osuga, N.,
(Mitsubishi Rayon Co. Ltd) Eur. Pat. Appl. EP 186106
(Chem. Abstr., 1986, 105, 114619a).
Brown, R. F. C., Eastwood, F. W., and Harrington, K. J.,
Aust. J. Chem., 1974, 27, 2373.
Ethyl 3-(12 0-Ethenyl-9 0,10 0-dihydro-9 0,10 0-
ethanoanthracen-11 0-yl)-3-oxo-2-triphenylphosphor-
anylidenepropanoate (24)
4
A solution of the acid chloride (22) (400 mg, 1 5 mmol) in
dry tetrahydrofuran (15 ml) was added dropwise to a boiling
solution of methyl (triphenylphosphoranylidene)ethanoate (1 0
g, 3 2 mmol) and triethylamine (0 2 ml, 1 5 mmol) in tetrahy-
drofuran (20 ml). Heating was continued for 6 h and then
the mixture was allowed to cool. The precipitated material
was removed by ltration and the ltrate was evaporated
under vacuum. Puri cation of the residue by ash chromatog-
raphy (SiO2; ethyl acetate/light petroleum, 1 : 1) gave the
title ester (24) (660 mg, 80%) as colourless crystals, m.p.
5
6
7
8
9
Wentrup, C., Gross, G., Berstermann, H.-M., and Lorencak,
P., J. Org. Chem., 1985, 50, 2877.
217–219 (Found: m/z, 606 234 0 006. C41H35O3P requires
10
11
12
1
.
31P
Maquestiau, A., Pauwels, P., Flammang, R., Lorencak,
P., and Wentrup, C., Org. Mass Spectrom., 1986, 21, 259.
Brown, R. F. C., Coulston, K. J., Eastwood, F. W., and
Irvine, M. J., Aust. J. Chem., 1991, 44, 87.
Brown, R. F. C., Browne, N. R., Coulston, K. J., Eastwood,
F. W., Irvine, M. J., Pullin, A. D. E., and Wiersum, U.
E., Aust. J. Chem., 1989, 42, 1321.
Finke, R. G., and Sorrell, T. N., Org. Synth., Collect. Vol.
6 (Ed. W. E. Noland), p. 807 (John Wiley: New York
1988).
Bartlett, P. D., and Tate, F. A., J. Am. Chem. Soc., 1953,
73, 91.
Friedrich, L. E., and Schuster, G. B., J. Am. Chem. Soc.,
1972, 94, 1193.
Bosshard, H. H., Mory, R., Schmid, M., and Zollinger,
Hch., Helv. Chim. Acta, 1959, 42, 1653.
Diels, O., and Alder, K., Justus Liebigs Ann. Chem., 1931,
486, 191.
m/z, 606 232).
n.m.r.
(Nujol) 1651 (C=O), 1557 cm
max
(120 MHz, CDCl3) 18 08, Ph3P=C. 1H n.m.r.
(200 MHz, CDCl3) 7 62–7 31, m, phenyl H; 7 25–6 87, m,
H 10–80; 5 43–5 25, m, ethenyl =CH–; 4 90–4 76, m, H 100,
=CH2; 4 06, d, J 2 3 Hz, H 90; 3 89–3 69, m, H 110, OCH2–;
3 23–3 14, m, H 120; 0 67, t, J 7 2 Hz, CH3. 13C n.m.r.
(50 MHz, CDCl3) 194 51, 194 45, C 3=O; 167 56, 167 21,
C 1=O; 144 50, 144 48, 141 54, 140 20, C 40a, C 80a, C 90a,
C 100a; 142 59, ethenyl =CH–; 133 21, 133 01, 131 32, 131 26,
128 39, 3 phenyl CH; 128 08, 126 22, phenyl quat.; 125 78,
125 62, 125 11, 124 95, 124 81, 124 58, 123 36, 123 09, C 10–
80; 113 77, ethenyl =CH2; 58 41, OCH2–; 50 39, C 110; 49 38,
C 90, C 100; 44 46, C 120; 13 81, CH3. Mass spectrum, m/z
606 (M, 28%), 375 (57), 303 (34), 262 (100), 178 (99).
13
14
15
16
17
18
19
20
Acknowledgment
This work was supported by the Australian Research
Council.
Ripoll, J. L., Lebrun, H., and Thuillier, A., Tetrahedron,
1980, 36, 2497.
Bachmann, W. E., and Scott, L. B., J. Am. Chem. Soc.,
1948, 70, 1458.
Reid, W., and Schinzel, H., Liebigs Ann. Chem., 1982,
1569.
References
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East, A. L. L., Allen, W. D., and Klippenstein, S. J., J.
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