Pyrolytic electrocyclization of arylmethylidene derivatives of glutacononitrile; synthesis of dihydroaromatic 1,3-dinitriles

Article abstract of DOI:10.1071/C98040

Condensation of seven aromatic aldehydes (1a-g) with glutacononitrile (2) gave 4-(arylmethylidene)pent-2-enedinitriles (3a-g). Flash vacuum pyrolysis of the dinitriles (3a-g) at 750°/0.02-0.03 mm gives annulated dihydroaromatic 1,3-dicarbonitriles by electrocyclic ring closure of (3). Fully aromatized products formed by secondary loss of H₂ or HCN are also obtained.

Full text of DOI:10.1071/C98040

C S I R O P U B L I S H I N G
Australian Journal
of Chemistry
Volume 51, 1998
©
CSIRO 1998
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Published by CSIRO PUBLISHING
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Aust. J. Chem., 1998, 51, 695–701
.
Pyrolytic Electrocyclization of
Arylmethylidene Derivatives of Glutacononitrile;
Synthesis of Dihydroaromatic 1,3-Dinitriles
Mircea D. Banciu, Roger F. C. Brown, Karen J. Coulston,
Frank W. Eastwood and Tamara Macrae
Chemistry Department, Monash University, Clayton, Vic. 3168.
Condensation of seven aromatic aldehydes (1a–g) with glutacononitrile (2) gave 4-(arylmethylidene)pent-
�
2
-enedinitriles (3a–g). Flash vacuum pyrolysis of the dinitriles (3a–g) at 750 /0�02–0�03 mm gives
annulated dihydroaromatic 1,3-dicarbonitriles by electrocyclic ring closure of (3). Fully aromatized
products formed by secondary loss of H2 or HCN are also obtained.
1
In earlier work in the triphenylene series we described
the synthesis of triphenylene-1,3-dicarbonitrile by con-
densation of phenanthrene-9-carbaldehyde (1d) with
glutacononitrile, and �ash vacuum pyrolysis (f.v.p.) of
the product (3d) to give mainly the dihydro dinitrile
F.V.P. of the Phenylmethylidene Dinitrile (3a)
The phenylmethylidene dinitrile (3a) was pyrolysed
�
through an unpacked silica tube at 750 /0�02 mm to
give an oil with 97% weight recovery. The major product
proved to be 1,2-dihydronaphthalene-1,3-dicarbonitrile
(
4) which could then be dehydrogenated. In this paper
we explore the scope of the same sequence as applied
to six further aromatic and heteroaromatic aldehydes.
(
6), accompanied by the 3,4-dihydro compound (9),
the fully aromatized dinitrile (8) and the 2-carbonitrile
7). We assume that the initial product of electro-
(
cyclization (5) undergoes [1,5]H shifts leading to (6)
and (9), and that minor elimination of H2 or HCN
then forms (8) and (7) (Scheme 2). The 3,4-dihydro
compound (9) was not fully puri�ed, but the pattern of
1
coupling in the H n.m.r. spectrum clearly showed the
presence of the system =CH–CH(CN)–CH2–. Addition
of triethylamine to the solution of the 3,4-dihydro com-
pound (9) destroyed this pattern because of the high
acidity of the NC–C(Ar)=CH–CH(CN)– substructure.
The structure of naphthalene-1,3-dicarbonitrile was
con�rmed by its alternative preparation by dehydro-
The initial condensation reaction of Scheme 1 was
carried out under a Dean and Stark water trap, and
the dinitrile products (3) were generally obtained in
satisfactory yield [64–97% for (3b–g)] by evapora-
tion and recrystallization of the residue. The more
soluble phenyl compound (3a) required chromato-
graphy and the yield (31%) was poor. The crude
products usually contained a mixture of stereoisomers,
but the recrystallized products were single isomers
with 2,3-E stereochemistry (J2,3 c. 16 Hz) but of
uncertain stereochemistry at the arylmethylidene-C 4
double bond.
Scheme 2. Yields shown were estimated by n.m.r. spectroscopy
of the pyrolysate.
Manuscript received 12 March 1998
᭧ CSIRO 1998
0004-9425/98/080695$ 05.00

6
96
M. D. Banciu et al.
2
genation of the known 5,6,7,8-tetrahydro derivative. In
The bay-region interaction 4-CN/H 5 probably dis-
favours accumulation of isomer (17) in an equilibrating
system.
1
the H n.m.r. spectra of both dihydro compounds the
system –CH(CN)–CH2– showed a simple t/d �rst-order
coupling pattern.
F.V.P. of the 1-Naphthyl- and 2-Naphthyl-methylidene
Dinitriles (3b) and (3c)
Pyrolysis of the 1-naphthylmethylidene compound
�
(
3b) at 740 /0�03 mm gave a pyrolysate (90% weight
recovery) which was found to contain the four major
products shown in Scheme 3.
The major 1,2-dihydro compound (10) and the
aromatized dinitrile (12) and mononitrile (13) were
readily obtained crystalline after radial chromatogra-
phy. Dehydrogenation of a similar pyrolysate with
2
,3-dichloro-5,6-dicyano-1,4-benzoquinone in chloroben-
zene gave phenanthrene-1,3-dicarbonitrile (12) in 25%
yield after chromatography. The fourth component,
the 3,4-dihydro compound (11), could not be isolated
by chromatography on silica because the conditions led
to dehydrogenation to produce (12), as did addition of
triethylamine in the presence of air. Nevertheless, the
Scheme 4. Yields shown were estimated by n.m.r. spectroscopy
of the pyrolysate.
1
F.V.P. of the 1-Methylindol-3-ylmethylidene
Dinitrile (3e)
H n.m.r. spectrum of (11), although complex, was
clearly visible from � 6�74–3�30 and spin-decoupling
experiments permitted the assignment of this region
to the system Ar–CHAHB–CHC(CN)–CHD=C(CN)–,
where the acidic proton is shown in bold (H 3 in
structure (11)).
�
Pyrolysis of the dinitrile (3e) at 740 /0�02 mm gave
an orange pyrolysate (97% weight recovery). This
was found to contain as major products 9-methyl-
1,2-dihydrocarbazole-1,3-dicarbonitrile (19) and the
carbazole dinitrile (20), with the mononitrile (22) as
the minor product (Scheme 5). The yields estimated
by n.m.r. add to only 55%, so that there is a dis-
crepancy between these and the yield of pyrolysate.
The most interesting feature of this pyrolysis is that
the mononitrile was not the expected 3-carbonitrile
(
21), which might have formed by 1,2-elimination of
HCN from the 1,2-dihydro compound (19), but the
-carbonitrile (22), which would require a dihydro-
1
carbazole precursor such as (23). The 1-carbonitrile
was not fully characterized (1 mg), but it was clearly
di�erent from 9-methylcarbazole-3-carbonitrile (21).
3
Spectra and a sample of (21) were kindly provided
by Professor H. Junjappa (North-Eastern Hill Univer-
sity, Meghalaya, India); in particular the 3-carbonitrile
1
showed a normal H n.m.r. N -methyl signal at �
3
�76, whereas our 1-carbonitrile showed the N -methyl
signal at 4�23. 9-Methylcarbazole-1,3-dicarbonitrile
20) similarly showed a down�eld N -methyl signal (�
(
Scheme 3. Yields shown were estimated by n.m.r. spectroscopy
of the pyrolysate.
4�28), which suggests that this down�eld shift is due
to the proximity of the N -methyl and 1-carbonitrile
functions.
The pyrolysis of the 2-naphthylmethylidene deriva-
tive (3c) followed a similar course, but 25% of the
sample failed to sublime into the hot tube. The prod-
ucts were the major 3,4-dihydrophenanthrene dinitrile
F.V.P. of the Pyrrol-2-ylmethylidene Dinitrile (3f)
The pyrolysate from the dinitrile (3f) was collected
in two fractions. The less volatile material which
collected in the inlet to the cold trap appeared to
contain dihydroindolizine or dihydroindole derivatives
(n.m.r.) but attempts at separation failed. The more
volatile fraction from the cold trap (47% weight recov-
(
14), accompanied by the aromatized dinitrile (15) and
the mononitrile (16) (Scheme 4). In this case, however,
the isomeric 1,2-dihydro compound (17) could not be
detected in the pyrolysate, even though it could in
principle be formed from (14) through [1,5]H shifts.

Pyrolytic Electrocyclization of Derivatives of Glutacononitrile
697
ery) could be separated by chromatography on alumina
into indolizine-7-carbonitrile (24) and a minor product,
indolizine-5,7-dicarbonitrile (25) (Scheme 6). Neither
compound was completely puri�ed or characterized,
but their n.m.r. characteristics were consistent with
of aromatized indolizines. A variant of this scheme
would involve direct cyclization of the pyrrole (3f) to
the dipolar species (28), an isomer of (27).
4
those of the parent indolizine.
Our failure to identify all of the major products
and the presence of a mobile (N)H in dinitrile (3f)
make rationalization of this experiment more di� -
cult. Nevertheless, a major product is the aromatized
mononitrile (24) which has lost HCN with respect
to (3f), and this result is quite di�erent from the
carbocyclic systems which form mainly dihydro dini-
triles. A simple mechanism for this cyclization would
involve initial equilibration of the pyrrole (3f) with
the 5H -pyrrolenine (26) which could then cyclize to
the 3,5-dihydroindolizine (27). The 1,8-elimination of
H–CN or H–H from the 3- and 5-positions may be a
favourable and allowed 10-electron process (Scheme 7).
This would account for the apparent preponderance
F.V.P. of 4-Methoxyphenylmethylidene Dinitrile (3g)
The pyrolytic behaviour of the 4-methoxyphenyl
compound (3g) was qualitatively similar to that of
the phenyl compound (3a) except that no mononitrile
was found, and demethylation to phenolic products
was prominent. The pyrolysate (95% weight recovery)
contained the expected methoxy dihydro dinitrile (29)
and the aromatized dinitrile (30), but the major fraction
was a mixture of the phenolic dihydro dinitrile (31) and
the aromatized phenolic dinitrile (32) (Scheme 8). The
high degree of demethylation under f.v.p. conditions
was unexpected, and its mechanism is uncertain; it
may be a radical process favoured by the delocalization
of the unpaired electron in the naphthoxy radicals
(
33), which would be the initial products of cleavage
of the methoxy groups of (29) and (30).
Scheme 8. Yields shown were estimated by n.m.r. spectroscopy
of the pyrolysate.
Scheme 5. Yields shown were estimated by n.m.r. spectroscopy
of the pyrolysate.
Conclusion
From the limited study reported here it seems likely
that condensation of an aromatic aldehyde with gluta-
cononitrile, f.v.p. of the product, and dehydrogenation
will be a widely applicable route to benzannulated
compounds bearing 1,3-dinitrile groups.
Scheme 6. Yields shown were estimated by n.m.r. spectroscopy
of the pyrolysate.

6
98
M. D. Banciu et al.
8
2
� CH; 136�94, 127�96, 110�49, 100�15, 4� Cq; 117�96, 116�5,
� CN. Mass spectrum: m/z 233 (M, 100%), 232 (95), 217
Experimental
For general experimental and directions for pyrolysis see
Aust. J. Chem., 1997, 50, 1159. Pyrolytic conditions are
summarized as (pyrolysis tube temperature, pressure, temper-
ature of sublimation of sample, time for complete sublimation).
Unless otherwise stated infrared spectra refer to para� n mulls.
(
26), 207 (19), 192 (16), 182 (16), 164 (17), 140 (12), 103 (18),
8
9 (12), 75 (13), 63 (12), 51 (10).
(
F) Pyrrole-2-carbaldehyde (0�95 g, 10 mmol) was simi-
0
larly condensed with glutacononitrile to give 4-(pyrrol-2 -
ylmethylidene)pent-2-enedinitrile (3f) (71%) as dark yellow
13
J-modulated C n.m.r. signals are usually grouped as CH and
CH3 signals, Cq, CN, and CH2 signals. RF values of pyrolysis
products refer to the adsorbent/solvent combination used for
radial or column chromatography.
�
crystals, m.p. 177–178 (Found: C, 70�9; H, 4�2; N, 24�7.
� 1
C10H7N3 requires C, 71�0; H, 4�2; N, 24�8%). �max 2211 cm
1
(
CN). H n.m.r. � (CDCl3, 200 MHz) 9�66, br s, NH; 7�20,
0
0
br s, H 5 ; 7�11, s, ArCH; 7�02, d, J 16�0 Hz, H 3; 6�85,
0
13
br s, H 3 ; 6�40–6�44, m, H 4 ; 5�63, d, J 16 Hz, H 2.
C
4
-(Arylmethylidene)pent-2-enedinitriles by Condensation of
n.m.r. � (CDCl3+(CD3)2SO, 100 MHz) 148�01, 139�56, 127�32,
Glutacononitrile with ArCHO
1
1
1
16�92, 112�70, 94�15, 6� CH; 127�32, 98�07, 2� Cq; 117�96,
16�03, 2� CN. Mass spectrum: m/z 169 (M, 82%), 168 (100),
43 (44), 142 (29), 141 (25), 118 (24), 115 (24), 114 (27), 88
(
A) Benzaldehyde (1�06 g, 10 mmol) and pent-2-enedinitrile
5
(
glutacononitrile, mixture of E and Z isomers, 0�92 g, 10 mmol)
were dissolved in benzene (100 ml) and a solution of �-alanine
(
18), 64 (21), 63 (29), 52 (25), 51 (28).
(
0�8 g) in acetic acid (15 ml) was added. The mixture was
(
G) 4-Methoxybenzaldehyde (1�50 g, 11 mmol) was similarly
0
heated under a Dean and Stark water trap for 2 h. The solution
was then decanted from the catalyst sludge and evaporated.
The residue was recrystallized from ethanol to give the product
condensed with glutacononitrile to give 4-(4 -methoxyphenyl-
methylidene)pent-2-enedinitrile (3g) (1�8 g, 78% crude) which
formed lustrous yellow crystals from ethyl acetate/light
�
(
(
0�68 g) as a mixture of stereoisomers. Flash chromatography
petroleum, m.p. 158–160 (Found: C, 74�3; H, 4�6; N,
silica; CH2Cl2/light petroleum, 1 : 1) separated the major iso-
1
2
8
3�4. C13H10N2O requires C, 74�3; H, 4�8; N, 13�3%). �max
�
1
1
mer of 4-(phenylmethylidene)pent-2-enedinitrile (3a) (0�55 g,
216 cm
�8 Hz, H 2 ; 7�22, s, ArCH; 7�10, d, J 16�0 Hz, H 3; 6�99, d,
(CN). H n.m.r. � (CDCl3, 200 MHz) 7�89, d, J
0
3
1%) which was recystallized from ethyl acetate/light petroleum
�
0
to give colourless crystals, m.p. 101–103 (dec.) (Found: C,
J 8�8 Hz, H 3 ; 5�80, d, J 16�0 Hz, H 2; 3�89, s, 3H, OMe.
13
0
8
0�0; H, 4�4; N, 15�2. C12H8N2 requires C, 80�0; H, 4�5;
C n.m.r. � (CDCl3, 50 MHz) 163�24, C 4 ; 150�22, ArCH;
� 1 1
0
0
0
N, 15�5%). �max 2218 (CN), 1610, 1594 cm
.
H n.m.r.
1
2
47�43, C 3; 132�65, C 2 , C 6 ; 124�98, C 1 ; 117�25, 115�13,
0 0
spectrum � (CDCl3, 400 MHz) 7�88, d, J 7�4 Hz, 2H, and
� CN; 114�89, C 3 , C 5 ; 104�65, C 4; 98�47, C 2; 55�64, OMe.
7
�55–7�45, m, 3H, phenyl; 7�31, s, PhCH; 7�13, d, J 16�0 Hz,
13
Mass spectrum: m/z 210 (M, 100%), 209 (84), 184 (29), 170
19), 141 (31), 140 (53), 114 (25), 63 (23), 51 (20), 50 (19).
H 3; 5�89, d, J 16�0 Hz, H 2. C n.m.r. spectrum � (CDCl3,
(
1
1
00 MHz) 150�66, PhCH; 146�82, C 3; 132�67, 132�17, 130�26,
29�37, phenyl; 116�81, 114�52, 2� CN; 107�98, C 4; 100�54,
Pyrolysis of 4-(Phenylmethylidene)pent-2-enedinitrile (3a)
C 2. Mass spectrum: m/z 180 (M, 89%), 179 (100), 165 (25),
1
54 (25), 153 (95), 152 (48), 140 (76), 63 (31), 58 (58), 51 (38).
The dinitrile (3a) (59 mg) was pyrolysed through an
�
(
B) 1-Naphthaldehyde (0�43 g, 2�7 mmol) was similarly con-
unpacked silica tube (300 by 25 mm i.d.) (750 , 0�02 mm,
0
�
densed with glutacononitrile to give 4-(1 -naphthylmethylidene)-
75 , 40 min) to give an oil (57 mg, 97% weight recovery).
pent-2-enedinitrile (3b) (0�60 g, 95%) as yellow crystals, m.p.
1,1,2,2-Tetrachloroethane (integration standard) was added to
the whole pyrolysate and the yields of cyclized products were esti-
mated as follows: (a) 1,2-dihydronaphthalene-1,3-dicarbonitrile
(6), 74%; (b) 3,4-dihydronaphthalene-1,3-dicarbonitrile (9),
13%; (c) naphthalene-2-carbonitrile (7), 7%; (d) naphthalene-
1,3-dicarbonitrile (8), 4%.
�
1
37–140 (Found: C, 83�3; H, 4�3; N, 12�2. C16H10N2 requires
�
1
1
C, 83�5; H, 4�4; N, 12�2%). �max 2218 cm
(CN). H n.m.r.
spectrum � (CDCl3, 200 MHz) 8�20, d, J 7�3 Hz, H 2 ; 8�15, s,
0
0
0
0
ArCH; 8�03, d, J 8�3 Hz, H 4 ; 7�94, m, H 5 , H 8 ; 7�69–7�55,
0
0
0
m, H 3 , H 6 , H 7 ; 7�32, dd, 1H, J 16�1, 0�7 Hz, H 3; 6�03,
dd, 1H, J 16�1, 0�7 Hz, H 2. Mass spectrum: m/z 230 (M,
(A) Flash chromatography of the pyrolysate (silica; CH2Cl2/
light petroleum, 1 : 1 to 1 : 0) and recrystallization (CDCl3/light
1
7
00%), 203 (70), 190 (58), 151 (10), 139 (5), 115 (10), 88 (19),
5 (8), 63 (7).
petroleum) a�orded
a
colourless sample (13 mg) of 1,2-
�
(
C) 2-Naphthaldehyde (0�49 g, 3�1 mmol) was similarly con-
dihydronaphthalene-1,3-dicarbonitrile (6), m.p. 116–117
(Found: C, 80�0; H, 4�5; N, 15�6. C12H8N2 requires C, 80�0;
0
densed with glutacononitrile to give 4-(2 -naphthylmethylidene)-
pent-2-enedinitrile (3c) (0�55 g, 77%) as pale yellow crystals,
�
1
1
H, 4�5; N, 15�6%). �max 2246w, 2205s cm
(2� CN).
H
�
m.p. 166–167 (Found: C, 83�6; H, 4�4; N, 12�2. C16H10N2
n.m.r. � (CDCl3, 400 MHz) 7�55–7�38, m, 3� ArH; 7�29–7�28,
�
1
requires C, 83�5; H, 4�4; N, 12�2%). �max 2214 cm
(CN).
1� ArH; 7�26, H 4; 4�16, t, J 8�8 Hz, H 1; 2�89, d with further
1
13
H n.m.r. � (CDCl3, 300 MHz) 8�27, s, ArCH; 8�09, d, J
coupling, J 8�7 Hz, (H 2)2.
C n.m.r. � (CDCl3, 400 MHz)
0
0
0
0
8
�7 Hz, H 4 ; 7�95–7�87, m, 3H, H 3 , H 5 , H 8 ; 7�65–7�55,
141�63, C 4; 131�55, 129�60, 128�94, 127�29, 4� CHaromatic;
130�16, 128�20, 2� Cq; 118�42, 117�99, 2� CN; 107�27, C 3;
29�55, C 1; 28�41, C 2. Mass spectrum: m/z 180 (M, 100%),
179 (73), 153 (75), 152 (35), 140 (95).
0
0
0
m, 2H, H 6 , H 7 ; 7�46, s, H 1 ; 7�19, d, J 16�3 Hz, H 3; 5�93,
d, J 16�3 Hz, H 2. Mass spectrum: m/z 230 (M, 94%), 229
(
(
100), 215 (21), 204 (21), 203 (64), 190 (34), 176 (17), 151
12), 126 (11), 115 (16), 101 (11), 88 (19), 75 (17), 63 (15),
(B) Repeated chromatography of a more mobile fraction
(8 mg) yielded a fraction (3 mg) considered to be mainly 3,4-
dihydronaphthalene-1,3-dicarbonitrile (9) but still contained
some 1,2-dihydro compound (6) and other impurities. The
5
1 (10).
D) Phenanthrene-9-carbaldehyde gave 4-(9 -phenanthryl-
0
(
1
�
methylidene)pent-2-enedinitrile (3d) (97%), m.p. 212–214 .
�
1
(
E) 1-Methylindole-3-carbaldehyde (0�43 g, 3�0 mmol) was
following spectra were assigned to (9). �max 2228 cm
(CN).
0
1
similarly condensed with glutacononitrile to give 4-(1 -
H n.m.r. � (CDCl3, 300 MHz) 7�6–7�3, m, 4� ArH; 6�71,
d, J 4�2 Hz, H 2; 3�77, td, J 8�7, 4�2 Hz, H 3; 3�21, d, J
8�7 Hz, (H 4)2. Addition of triethylamine to this n.m.r. sample
removed the characteristic coupling pattern and gave broad
signals. The mass spectrum, m/z 180 (M, 100%), was similar
to that of the 1,2-dihydro compound (6).
0
methylindol-3 -ylmethylidene)pent-2-enedinitrile (3e) (0�45 g,
�
6
4%) as orange crystals from hexane, m.p. 242–243 (Found:
C, 77�1; H, 4�6; N, 18�0. C15H11N3 requires C, 77�2; H,
�
1
1
4
2
7
1
1
�8; N, 18�0%). �max 2210 cm
(CN). H n.m.r. � (CDCl3,
00 MHz) 8�41, s, ArCH; 8�21, s, H 2; 7�85–7�89, m, H 4;
0
�56–7�64, m, H 3 , H 7; 7�30–7�40, m, H 5, H 6; 5�73, d, J
(C) Isolation of naphthalene-2-carbonitrile (7) directly from
the pyrolysate was di� cult. Instead a similar pyrolysate
(60 mg) was dehydrogenated with 2,3-dichloro-5,6-dicyano-1,4-
0
13
6�2 Hz, H 2 ; 3�97, s, NMe. C n.m.r. � (CDCl3, 100 MHz)
47�56, 141�58, 133�18, 123�95, 122�48, 118�11, 110�52, 95�20,

Pyrolytic Electrocyclization of Derivatives of Glutacononitrile
benzoquinone (180 mg) in boiling chlorobenzene (5 ml) for
699
splittings: JA,C 11�5, JB,C 7�1, JA,B 16, JC,D 4�2 Hz. The
1
2
0 h. The cooled solution was �ltered and evaporated to an oil
which was chromatographed (silica; CH2Cl2/light petroleum,
: 1 to 1 : 0) to give �rst the crude 2-carbonitrile (7) (5 mg) as
composition of the pyrolysates was examined by H n.m.r.
spectroscopy with an internal integration standard for (a) a
fresh pyrolysate; (b) a pyrolysate fully recovered from radial
chromatography on silica; and (c) a pyrolysate to which one
drop of triethylamine had been added. For both (b) and (c)
integration showed that the 3,4-dihydro compound (11) had
undergone dehydrogenation to phenanthrene-1,3-dicarbonitrile
(12).
2
a brown solid, followed by the 1,3-dicarbonitrile (8) (45 mg).
The following major spectroscopic characteristics of the crude
2
-carbonitrile (7) were identical with those of an authentic
6
� 1
1
sample. �max 2226 cm (CN). H n.m.r. � (CDCl3, 200 MHz)
�25, s, H 1; 8�0–7�85, m, 3H; 7�7–7�57, m, 3H. Mass spectrum:
m/z 153 (M, 100%), 127 (6), 126 (16), 127 (5).
D) The dinitrile fraction from (C) was recrystallized
8
(C) Recrystallization of the fraction with RF 0�49 from
(
hexane gave phenanthrene-3-carbonitrile (13) (5 mg) as pale
�
8
�
� 1
from ethyl acetate/light petroleum to give naphthalene-1,3-
yellow crystals, m.p. 99�5–100 (lit. 102 ). �max 2204 cm
13
�
1
dicarbonitrile (8) (30 mg) as colourless crystals, m.p. 226–227
(
(CN). H n.m.r. � (CDCl3, 200 MHz) 9�02, s, H 4; 8�65, d, J
�
7
�
subl. >180 ) (lit. 179 ) (Found: C, 80�8; H, 3�4; N, 15�7.
7�5 Hz, H 5; 8�0–7�85, m, 3H; 7�82–7�65, m, 4H. C n.m.r.
Calc. for C12H6N2: C, 80�9; H, 3�4; N, 15�7%). �max
� (CDCl3, 100 MHz) 134�33, 132�30, 130�08, 128�81, 109�91,
5� Cq; 119�54, CN; 130�40, 129�54, 128�94, 128�27, 128�00,
127�87, 127�76, 126�09, 122�63, 9� CH. Mass spectrum: m/z
203 (M, 100%), 202 (29), 201 (22), 177 (12), 176 (17), 174 (8),
151 (6), 150 (9), 88 (21), 87 (13), 75 (11).
�
1
1
2
238 cm
(CN). H n.m.r. � (CDCl3, 400 MHz) 8�46, br s,
H 4; 8�32, dd, J 8�4, 0�9 Hz, H 8; 8�05, d, J 1�6 Hz, H 2;
8
�03, d, J 8�3 Hz, H 5; 7�90, td, J 7�0, 1�3 Hz, and 7�79,
13
td, J 7�0, 1�1 Hz, H 6, H 7.
C n.m.r. � (CDCl3, 100 MHz)
1
1
38�52, 132�65, 131�87, 129�48, 129�34, 125�60, 6� CH; 133�36,
(D) (i) Recrystallization of the fraction with RF 0�37 from
32�17, 112�42, 109�42, 4� Cq; 117�16, 115�85, 2� CN. Mass
hexane gave phenanthrene-1,3-dicarbonitrile (12) (11 mg) as
�
spectrum: m/z 178 (M, 100%), 177 (9), 152 (5), 151 (27), 150
5), 124 (6), 76 (8), 75 (13), 74 (9). An alternate synthesis of
compound (8) was as follows. 5,6,7,8-Tetrahydronaphthalene-
colourless crystals, m.p. 212–213 (Found: C, 84�2; H, 3�6; N,
(
12�2. C16H8N2 requires C, 84�2; H, 3�5; N, 12�3%). �max
�
1
1
(KBr) 2230 cm (CN). H n.m.r. � (CDCl3 300 MHz) 9�22, s,
H 4; 8�67, d, J 7�6 Hz, H 5; 8�20, d, J 8�7 Hz, and 8�14, d, J
8�7 Hz, H 10,9; 8�16, s, H 2; 8�04, d, J 7�6 Hz, H 8; 7�88–7�78,
2
1
,3-dicarbonitrile (tetrahydro-(8)) (57 mg) and 10% Pd/C
(
10 mg) in o-dichlorobenzene (3 ml) were heated under re�ux
13
for 36 h. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (180 mg)
was added and re�ux was continued for 4 days. The reaction
mixture was worked up as in (C)/(D) to give naphthalene-1,3-
m, H 6,7.
C n.m.r. � (CDCl3, 100 MHz) 133�69, 132�20,
129�61, 126�92, 126�23, 107�44, 6� Cq; 118�40, 118�50, 2� CN;
137�37, 129�06, 128�36, 127�17, 124�37, 122�08, 113�41, 7
signals for 8� CH. Mass spectrum: m/z 228 (M, 100%), 201
(10), 175 (5), 150 (3), 114 (8), 100 (8). (ii) The title dinitrile
(3b) (61 mg, 0�265 mmol) was pyrolysed as described above
and the pyrolysate in chlorobenzene (10 ml) was heated under
re�ux with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (86 mg,
�
�
dicarbonitrile (8) (36 mg), m.p. 226–227 (subl. >180 ), iden-
tical in all respects with the sample above from the pyrolysate.
Attempted dehydrogenation of tetrahydro-(8) with either 2,3-
dichloro-5,6-dicyano-1,4-benzoquinone/chlorobenzene alone or
Pd/C in o-dichlorobenzene alone failed.
0
�38 mmol) added in 2 portions over 10 h. Radial chro-
0
matography (silica; ethyl acetate/light petroleum, 1 : 5) of
the product soluble in CH2Cl2/light petroleum (1 : 1) gave
phenanthrene-1,3-dicarbonitrile (12) (11 mg, 25%).
Pyrolysis of 4-(1 -Naphthylmethylidene)pent-2-enedinitrile (3b)
�
The title dinitrile (3b) (75 mg) was pyrolysed (740 , 0�03 mm,
�
1
20 , 1�5 h) to give a brown solid (68 mg); a residue (7 mg)
1
remained in the sublimation tube. The H n.m.r. spectrum of the
pyrolysate was run after addition of 1,1,2,2-tetrachloroethane
0
Pyrolysis of 4-(2 -Naphthylmethylidene)pent-2-enedinitrile (3c)
(
5 �l) as integration standard, and the yields of cyclized prod-
ucts were estimated as follows: (a) 1,2-dihydrophenanthrene-
,3-dicarbonitrile (10), 47%; (b) 3,4-dihydrophenanthrene-1,3-
dicarbonitrile (11), 16%; (c) phenanthrene-1,3-dicarbonitrile
12), 3%; (d) phenanthrene-3-carbonitrile (13), 3%. Individual
compounds were separated by radial chromatography (silica;
mm, ethyl acetate/light petroleum, 1 : 4); the fractions were
checked by t.l.c. in the same solvent, and recycled if necessary.
The title dinitrile (3c) (59 mg, 0�26 mmol) was pyrolysed
�
�
(750 , 0�02 mm, 100 , 3 h) to give a brown solid pyrolysate
(44 mg) and a residue (15 mg) in the sublimation tube. T.l.c.
(silica; ethyl acetate/light petroleum, 1 : 9) of the pyrolysate
showed that three components were present, and this was con-
1
(
1
�rmed by H n.m.r. spectroscopy of the whole pyrolysate with
1
1,1,2,2-tetrachloroethane (5 �l, 0�047 mmol) added as integra-
tion standard. Yields of cyclized products were estimated
as follows: (a) 3,4-dihydrophenanthrene-2,4-dicarbonitrile (14),
36%; (b) phenanthrene-2,4-dicarbonitrile (15), 27%; (c) phenan-
threne 2-carbonitrile (16), 10%. Samples of the three products
were separated by radial chromatography on silica (ethyl
acetate/light petroleum, 1 : 9).
(
A) Recrystallization of the fraction with RF 0�23 from
ethanol gave 1,2-dihydrophenanthrene-1,3-dicarbonitrile (10)
(
8
1
4
1
�
18 mg) as pale yellow crystals, m.p. 148–150 (Found: C,
3�6; H, 4�2; N, 12�1. C16H10N2 requires C, 83�5; H, 4�4; N,
� 1 1
2�2%). �max (KBr) 2223 cm
(CN). H n.m.r. � (CDCl3,
00 MHz) 8�12, s, H 4; 8�08, d, J 8�5 Hz, 1H; 7�98, d, J 8�4 Hz,
(A) Recrystallization of the fraction with RF 0�14 from
H; 7�90, d, J 7�1 Hz, 1H; 7�68–7�57, m, H 6, H 7, H 10; 4�39,
hexane/CH2Cl2 gave 3,4-dihydrophenanthrene-2,4-dicarbonitrile
13
�
t, J 8�0 Hz, H 1; 3�30, d, J 8�1 Hz, (H 2)2.
C n.m.r. �
(14) (21 mg) as pale yellow crystals, m.p. 205–206 , which did
(
5
1
CDCl3, 100 MHz) 133�69, 129�61, 126�93, 126�23, 107�40,
not give satisfactory microanalyses (Found: C, 80�4, 81�5; H,
� Cq; 118�5, 118�4, 2� CN; 137�37, 132�20, 129�06, 128�36,
27�17, 124�38, 122�08, 7� CHaromatic; 30�38, CH(CN); 28�09,
4�0, 3�7; N, 11�1, 12�3%; m/z, 230�085. C16H10N2 requires
�
1
C, 83�5; H, 4�4; N, 12�2%; m/z, 230�084). �max 2232 cm
1
CH2. Mass spectrum: m/z 230 (M, 100%), 203 (30), 190 (33),
1
(CN). H n.m.r. � (CDCl3, 400 MHz) 7�98, d, J 8�5 Hz, H 5;
7�92, 7�90, collapsed AB system (?), H 9,10; 7�69, br t, J
7�6 Hz, and 7�61, br t, J 8�0 Hz, H 6,7; 7�47, d, J 3�1 Hz,
H 1; 7�38, d, J 8�5 Hz, H 8; 4�79, dd, J 7�4, 1�6 Hz, H 4;
3�10, dd, JA,B 17�1, JB,4 1�7 Hz, 3-HAHB; 2�94, ddd, JA,B
17�1, JA,4 7�4, JA,1 3�1 Hz, 3-HAHB. All samples showed a
peak at � 4�3 (retained CH2Cl2). Mass spectrum: m/z 230
(M, 100%), 228 (90), 201 (80), 176 (54), 175 (25), 126 (10).
(B) (i) Recrystallization of the fraction with RF 0�30
from hexane/CH2Cl2 gave phenanthrene-2,4-dicarbonitrile (15)
51 (7), 115 (7), 88 (11), 75 (7).
B) 3,4-Dihydrophenanthrene-1,3-dicarbonitrile (11) could
(
not be isolated from the pyrolysates because it was destroyed
by chromatography on silica. Its presence was inferred from
the following H n.m.r. signals in the pyrolysate. � (CDCl3,
1
2
00 MHz) 6�74, d, J 4�2 Hz, H 2; 3�90–3�80, m, H 3; 3�75–3�30,
m, (H 4)2. Spin decoupling with irradiation of H 2 simpli�ed
the spectrum so that it appeared consistent with a system Ar–
CHAHB–CHC(CN)–CHD=C(CN)– with the following observed

7
00
M. D. Banciu et al.
�
(
8
16 mg) as light brown crystals, m.p. 183–184 (Found: C,
(C) Recrystallization of the fraction with RF 0�50 from
4�2; H, 3�6; N, 12�1. C16H8N2 requires C, 84�2; H, 3�5;
hexane gave 9-methylcarbazole-1-carbonitrile (22) (1 mg, 2%)
�
1
1
1
N, 12�3%). �max 2235 cm
(CN). H n.m.r. � (400 MHz,
as a smear of yellow crystals. H n.m.r. � (300 MHz, CDCl3)
CDCl3) 9�83, br d, J 9�6 Hz, H 5; 8�43, d, J 1�8 Hz, H 3;
8�28, dd, J 7�7, 1�1 Hz, H 4; 8�10, br d, J 7�7 Hz, H 5; 7�74,
dd, J 7�7, 1�1 Hz, H 2; 7�57, td, J 7�2, 1�0 Hz, and 7�32,
br t, J 7�9 Hz, H 6,7; 7�47, d, J 8�3 Hz, H 8; 7�25, t, J
8
7
�
1
1
�24, d, J 1�8 Hz, H 1; 8�01, m, H 8; 7�98, d, J 8�9 Hz, and
13
�78, d, J 8�9 Hz, H 9,10; 7�88–7�80, m, H 6,7.
C n.m.r.
1
3
(100 MHz, CDCl3) 137�86, 136�61, 131�18, 129�93, 129�36,
7�7 Hz, H 3; 4�23, s, NMe.
C n.m.r. � (100 MHz, CDCl3)
28�29, 125�94, 125�31, 8� CH; 134�14, 133�03, 132�01, 128�06,
131�60, 127�21, 125�05, 120�42, 120�39, 118�73, 109�09,
7� CH; 124�82, 121�83, 109�09, 3� Cq (2� Cq not observed);
118�80, CN; 30�57, NMe. Mass spectrum: m/z 206 (M, 100%),
205 (75), 191 (9), 177 (11), 164 (8), 151 (12), 103 (18), 75 (10).
09�44, 109�33, 6� Cq; 119�71, 116�89, 2� CN. Mass spectrum:
m/z 228 (M, 100%), 227 (15), 201 (14), 200 (11), 175 (8), 114
(
(
9), 87 (12). (ii) A similar pyrolysate (40 mg) from the dinitrile
3c) (51 mg) was dissolved in boiling chlorobenzene (10 ml) and
0
Pyrolysis of 4-(Pyrrol-2 -ylmethylidene)pent-2-enedinitrile (3f)
treated with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (40 mg,
with a second addition of 40 mg after 5 h). After 20 h the
solution was �ltered and evaporated and the residue was sub-
jected to radial chromatography. The main fraction yielded
phenanthrene-2,4-dicarbonitrile (15) (30 mg, 59% from (3c)),
The title dinitrile (3f) (40 mg, 0�28 mmol) was pyrolysed
�
�
(
750 , 0�03 mm, 90 , 3 h) and the pyrolysate (19 mg) which
collected on the cold �nger was collected separately from
material (18 mg) which deposited on the inlet to the trap.
Chromatography of the cold-�nger fraction on basic alumina
�
m.p. 183–184 , which showed spectra identical with those from
(
i).
(
CH2Cl2/light petroleum, 2 : 3, gradient to CH2Cl2) yielded (a)
indolizine-7-carbonitrile (24), 40% yield in pyrolysate by n.m.r.;
b) indolizine-5,7-dicarbonitrile (25), 4% yield by n.m.r. The
(
C) Recrystallization of the fraction with RF 0�40 from
hexane gave phenanthrene-2-carbonitrile (16) (3 mg) as yel-
(
�
8
�
low crystals, m.p. 106–107 (lit. 108–109�5 ). �max (KBr)
inlet fraction appeared to contain dihydroindolizine derivatives
�
1
1
1
2
8
7
3
1
1
227 cm
�6 Hz, H 4; 8�67, br d, J 7�5 Hz, H 5; 8�23, d, J 1�7 Hz, H 1;
�93, br d, J 7�1 Hz, H 8; 7�89–7�81, m, 2H; 7�77–7�68, m,
(CN). H n.m.r. � (400 MHz, CDCl3) 8�74, d, J
and indole derivatives ( H n.m.r.) but attempts at separation
failed.
(
A) Fraction (a), RF 0�48, yielded crude indolizine-7-
13
�
H. C n.m.r. � (100 MHz, CDCl3) 133�63, 128�97, 128�91,
28�29, 127�99, 127�48, 125�98, 123�86, 123�22, 9� CH;
33�02, 132�89, 131�55, 129�41, 110�00, 5� Cq; 119�14, CN.
carbonitrile (24) (6 mg) as oily crystals, m.p. 50–60 (Found:
m/z 142�053� 0�001. Calc. for C9H6N2: m/z, 142�053). �max
�
1
1
2
7
218 cm
�2 Hz, H 5; 7�81, br s, H 8; 7�45, br d, J 2�5 Hz, H 3; 6�93,
(CN). H n.m.r. � (400 MHz, CDCl3) 7�93, d, J
Mass spectrum: m/z 203 (M, 100%), 201 (45), 191 (43), 190
(
31), 176 (27), 174 (12), 150 (10), 102 (12).
dd, J 4�1, 2�6 Hz, H 2; 6�72, d, J 4�1 Hz, H 1; 6�56, dd,
13
J 7�2, 1�7 Hz, H 6.
C n.m.r. � (100 MHz, CDCl3) 126�62,
0
0
Pyrolysis of 4-(1 -Methylindol-3 -ylmethylidene)pent-2-
enedinitrile (3e)
116�09, 109�87, 104�80, 4� CH (6� CH expected); 125�37,
99�20, 2� Cq; 119�14, CN. Mass spectrum: m/z 142 (M,
1
00%), 115 (31), 114 (22), 88 (12), 71 (20), 57 (23).
The title dinitrile (3e) (60 mg, 0�26 mmol) was pyrolysed
�
�
(B) Fraction (b), RF 0�42, yielded crude indolizine-5,7-
(
740 , 0�02 mm, 160 , 2�5 h) to give an orange solid (58 mg).
1
1
dicarbonitrile (25) (<1 mg) as a crystalline smear. H n.m.r.
This was examined by H n.m.r. spectroscopy after addition of
�
2
(400 MHz, CDCl3) 8�03, d, J 1�4 Hz, H 8; 7�88, br d, J
1
,1,2,2-tetrachloroethane as integration standard, and by t.l.c.,
and the yields of the three major products were estimated
as follows: (a) 9-methyl-1,2-dihydrocarbazole-1,3-dicarbonitrile
19), 31%; (b) 9-methylcarbazole-1,3-dicarbonitrile (20), 18%;
c) 9-methylcarbazole-1-carbonitrile (22), 6%. These products
�6 Hz, H 3; 7�22, d, J 1�5 Hz, H 6; 7�14, dd, J 4�2, 2�7 Hz,
H 2; 7�01, dd, J 4�2, 0�9 Hz, H 1. Mass spectrum: m/z 167
(
(
M, 100%), 140 (19), 130 (15), 129 (14), 113 (11), 87 (12), 75
15), 63 (22), 62 (20), 51 (29), 50 (24).
(
(
were separated by radial chromatography (1 mm silica plate;
ethyl acetate/light petroleum, 15 : 85).
0
Pyrolysis of 4-(4 -Methoxyphenylmethylidene)pent-2-
enedinitrile (3g)
(
A) Recrystallization of the fraction with RF 0�13 from
The title dinitrile (3g) (100 mg, 0�48 mmol) was pyrolysed
ethanol gave 9-methyl-1,2-dihydrocarbazole-1,3-dicarbonitrile
19) (15 mg, 25%) as orange crystals, m.p. 189–190 (Found:
�
�
�
(
750 , 0�03 mm, 80 , 3 h) to give a pyrolysate which was
(
sublimed completely onto the cold �nger (heat gun) and ulti-
mately washed from the cold �nger with acetone to yield a
m/z, 233�095� 0�001. C15H11N3 requires m/z, 233�095).
�
1
1
�max (KBr) 2211 cm
(CN). H n.m.r. � (300 MHz, CDCl3)
1
pale yellow solid (95 mg). Analysis of this solid by H n.m.r. in
7
�64, d, J 7�8 Hz, H 5; 7�60, t, J 1�3 Hz, H 4; 7�4–7�23,
(
D6)acetone by t.l.c., and by column chromatography (silica;
CH2Cl2/light petroleum, 1 : 1, followed by CH2Cl2/MeOH,
: 1) led to the following estimate of pyrolytic yields: (a) 7-
methoxy-1,2-dihydronaphthalene-1,3-dicarbonitrile (29), 25%;
b) 7-methoxy-naphthalene-1,3-dicarbonitrile (30), 7%; start-
ing material (3g), 11%; (c) 7-hydroxy-1,2-dihydronaphthalene-
,3-dicarbonitrile (31), 36%; (d) 7-hydroxynaphthalene-1,3-
dicarbonitrile (32), (21%). sparingly soluble fraction
19 mg) containing mainly the dihydronaphthol dinitrile (31)
was obtained by stirring the pyrolysate with chloroform, and
the �ltrate was chromatographed as above. The most polar
fractions yielded a mixture of the dihydronaphthol dinitrile
31) and the naphthol dinitrile (32), but attempts to separate
or purify these compounds led to further dehydrogenation and
ultimately isolation of (32).
m, 3H; 4�28, t, J 6�2 Hz, H 1; 3�85, s, NMe; 3�06, dd, J
13
6
1
1
2
1
�2, 1�4 Hz, (H 2)2.
C n.m.r. � (100 MHz, CDCl3) 135�99,
9
22�27, 120�86, 110�20, 95�39, 5� CH; 138�16, 129�82, 128�35,
24�50, 119�60, 5� Cq; 118�59, 116�93, 2� CN; 29�69. C 2;
3�28, NMe; C 1 not observed. Mass spectrum: m/z 233 (M,
00%), 232 (55), 231 (28), 230 (17), 217 (26), 207 (31), 192
(
1
(
(
23), 177 (9), 164 (13), 151 (9), 103 (14), 89 (9), 75 (12), 63
9).
A
(
(
B) Recrystallization of the fraction with RF 0�27 from
hexane gave 9-methylcarbazole-1,3-dicarbonitrile (20) (8 mg,
�
1
2
2
1
4%) as slightly yellow crystals, m.p. 175–176 (Found: m/z,
31�080� 0�002. C15H9N3 requires m/z, 231�0796). �max
�
1
1
(
225 cm
(CN). H n.m.r. � (400 MHz, CDCl3) 8�52, d, J
�5 Hz, H 4; 8�13, d, J 7�8 Hz, H 5; 7�98, d, J 1�5 Hz, H 2;
�67, t, J 7�2 Hz, and 7�44, t, J 7�3 Hz, H 6,7; 7�54, d,
7
13
(
A) Recrystallization of a colourless crystalline fraction
J 8�3 Hz, H 8; 4�28, NMe.
C n.m.r. � (100 MHz, CDCl3)
(
30 mg) with RF 0�40 from ethyl acetate/light petroleum
1
1
2
28�95, 127�90, 125�13, 120�86, 120�44, 109�10, 6� CH; 142�56,
gave 7-methoxy-1,2-dihydronaphthalene-1,3-dicarbonitrile (29)
41�53, 122�95, 121�84, 120�85, 101�61, 6� Cq; 118�27, 116�68,
� CN; 29�31, NMe. Mass spectrum: m/z 231 (M, 100%), 230
�
(
12 mg), as colourless crystals, m.p. 166–168 (Found: C, 74�2;
H, 4�7; N, 13�2. C13H10N2O requires C, 74�3; H, 4�8; N,
(
60), 206 (13), 189 (9), 176 (11).

Pyrolytic Electrocyclization of Derivatives of Glutacononitrile
701
�
1
1
1
(
7
8
�
3�3%). �max 2205m, 2247w cm
(2� CN). H n.m.r. �
(D) The sparingly soluble and polar fractions with RF 0�05–
0�06 were combined and recrystallized from ethyl acetate–light
400 MHz, CDCl3) 7�24, br s, H 4; 7�21, d, J 8�4 Hz, H 5;
�
�05, br s, H 8; 6�90, dd, J 8�4, 2�4 Hz, H 6; 4�13, t, J
petroleum. The product (8 mg) was sublimed at 150 /0�02 mm,
13
�9 Hz, H 1; 3�88, s, OMe; 2�85, d, J 9�1 Hz, H 2. C n.m.r.
(100 MHz, CDCl3) 141�38, 130�61, 114�22, 113�59, 4� CH;
and the sublimate was washed with dichloromethane to give
7-hydroxynaphthalene-1,3-dicarbonitrile (32) as a white pow-
�
5
4
5�68, OMe; 29�94, CH(CN); 162�04, 130�10, 123�10, 103�65,
� Cq; 118�52, 118�49, 2� CN; 28�10, CH2. Mass spectrum:
der, m.p. 280–282 (subl.) (Found: m/z, 194�048� 0�002.
C12H6N2O requires m/z, 194�048).
�max 3282 (OH),
(CN). H n.m.r. spectrum � (400 MHz,
�
1
1
m/z 210 (M, 100%), 209 (40), 195 (7), 194 (8), 184 (8), 183
2241w, 2217m cm
(
9), 170 (51), 165 (16), 140 (37), 63 (18).
B) Recrystallization of pale yellow solid (11 mg)
(D6)acetone) 8�66, br s, H 4; 8�26, d, J 1�6 Hz, H 2; 8�15, d, J
(
a
8�9 Hz, H 5; 7�55, d, J 2�4 Hz, H 8; 7�46, dd, J 8�9, 2�4 Hz,
13
with RF 0�56 from ethyl acetate/light petroleum gave
H 6; OH not observed.
C n.m.r. spectrum � (100 MHz,
�
7
(
2
-methoxynaphthalene-1,3-dicarbonitrile (30), m.p. 208–210
(D6)acetone) 139�45, 134�60, 133�00, 122�71, 107�40, 5� CH;
161�79, 136�59, 128�03, 113�70, 110�22, 5� Cq; 118�44, 116�98,
2� CN. Mass spectrum: m/z 194 (M, 100%), 166 (10), 165
(19), 139 (25), 138 (14).
Found: m/z, 208�064� 0�002. C13H8N2O requires m/z,
�
1
1
08�064). �max 2228 cm
(CN). H n.m.r. � (400 MHz,
CDCl3) 8�33, br s, H 4; 8�01, d, J 1�6 Hz, H 2; 7�89, d, J
9
�0 Hz, H 5; 7�50, d, J 2�4 Hz, H 8; 7�38, dd, J 9�0, 2�4 Hz,
13
H 6; 4�04, s, OMe.
C n.m.r. � (100 MHz, CDCl3) 137�82,
Acknowledgments
1
1
33�43, 130�97, 122�72, 103�56, 5� CH; 56�03, OMe; 162�50,
This work was supported by the Australian Research
Council. R.F.C.B. thanks the School of Chemistry,
University of Melbourne, for hospitality during the
preparation of this paper.
35�80, 127�71, 110�44, 106�59, 5� Cq; 117�52, 116�29, 2� CN.
Mass spectrum: m/z 208 (M, 100%), 179 (11), 178 (32), 166
12), 165 (79), 139 (11), 138 (29).
C) The solid with RF 0�05–0�06, sparingly soluble in chlo-
roform, contained both the fully aromatized naphthol dinitrile
(
(
References
(
(
32) and 7-hydroxy-1,2-dihydronaphthalene-1,3-dicarbonitrile
31) in the ratio 1 : 3. The polar column fractions were sim-
1
Banciu, M. D., Brown, R. F. C., Coulston, K. J., East-
ilar in composition. The dihydro compound (31) could not
be separated, but the structure is based upon the following
spectra. The resonances in the H n.m.r. spectrum (400 MHz,
wood, F. W., Jurss, C., Mavropoulos, I., Stanescu, M., and
Wiersum, U. E., Aust. J. Chem., 1996, 49, 965.
Brown, R. F. C., and McAllan, C. G., Aust. J. Chem.,
1977, 30, 1747.
Rao, M. V. B., Satyanarayana, J., Ila, H., and Junjappa,
H., Tetrahedron Lett., 1995, 36, 3385.
Black, P. J., He�ernan, M. L., Jackman, L. M., Porter, Q.
N., and Underwood, G. R., Aust. J. Chem., 1964, 17, 1128.
Johnson, F., Panella, J. P., Carlson, A. A., and Hunneman,
D. H., J. Org. Chem., 1962, 27, 2473.
Norris, J. F., and Klemka, A. J., J. Am. Chem. Soc., 1940,
62, 1432.
1
2
(
D6)acetone of the dihydro compound (31) did not overlap
with those of the minor component (32) (reported in D): �
�17, br s, OH; 7�40, br s, H 4; 7�30, d, J 8�3 Hz, H 5; 7�02,
d, J 2�4 Hz, H 8; 6�89, dd, J 8�3, 2�4 Hz, H 6; 4�4, dd, J 8�9,
�7 Hz, H 1C; 2�93, ddd, JA,B 16�6, JB,C 6�7, J2,4 1�5 Hz,
H 2B; 2�85, ddd, JA,B 16�6, JA,C 8�9, J2,4 1�5 Hz, H 2A.
3
9
4
6
5
1
3
C n.m.r. spectrum � (100 MHz, (D6)acetone) 141�91, 131�80,
16�58, 115�61, 30�01, 5� CH; 160�99, 132�33, 123�52, 104�42,
� Cq; 120�02, 119�54, 2� CN; 28�74, CH2. �max (mixture)
6
1
4
3
�
1
7
297 (OH), 2240, 2217 cm
(CN). Mass spectrum: m/z (M
Bradbrook, E. F., and Linstead, R. P., J. Chem. Soc., 1936,
1739.
Bachmann, W. E., J. Am. Chem. Soc., 1935, 57, 555.
region of mixture; M r C12H8N2O, 196) 196 (68%), 195 (48),
94 (100).
8
1