Reactions of diethyl azulene-1,3-dicarboxylate derivatives and 1-azaazulene derivatives with Grignard reagents, and alkyl- and aryllithium

Article abstract of DOI:10.1039/b003078n

Reactions of diethyl azulene-1,3-dicarboxylate (1) and diethyl 2-chloroazulene-1,3-dicarboxylate (11) with Grignard reagents, followed by dehydration with tetrachloro-1,2-benzoquinone, gave 2-, 4,- and 6-substituted additionoxidation products. Grignards reagents have a tendency to react with 1 at the positions in the order of 2 > 4 > 6, while steric hindrance has a greater influence at the positions in order of 2 > 4 > 6. Reactions of 1 and 11 with phenyllithium and methyllithium gave similar results. On the other hand, on the reaction of diethyl 2-methoxy-azulene-1,3-dicarboxylate (15), Grignard reagents attacked preferentially at the methoxy group, and 2-substituted products were obtained. Use of excess molar equivalents of Grignard reagents led to diaryl-substituted products. Reaction of 2-chloro-1-azaazulenes with Grignard reagents also gave similar addition-oxidation products, and reacted at the positions in the order 8 ? 4 > 6, whereas reaction of 2-methoxy-1-azaazulene with a Grignard reagent gave 1-azaazulen-2(1H)-one. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/b003078n

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Reactions of diethyl azulene-1,3-dicarboxylate derivatives and
1-azaazulene derivatives with Grignard reagents, and alkyl- and
aryllithium
1
Tadayoshi Morita,*a Noritaka Abe*b and Kahei Takasea
a Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki,
Aoba-Ku, Sendai 980–8578, Japan
b Department of Chemistry, Faculty of Science, Yamaguchi University, Yamaguchi 753–8512,
Japan
Received (in Cambridge, UK) 17th April 2000, Accepted 17th July 2000
Published on the Web 23rd August 2000
Reactions of diethyl azulene-1,3-dicarboxylate (1) and diethyl 2-chloroazulene-1,3-dicarboxylate (11) with Grignard
reagents, followed by dehydration with tetrachloro-1,2-benzoquinone, gave 2-, 4,- and 6-substituted addition–
oxidation products. Grignards reagents have a tendency to react with 1 at the positions in the order of 2 > 4 > 6,
while steric hindrance has a greater influence at the positions in order of 2 > 4 > 6. Reactions of 1 and 11 with
phenyllithium and methyllithium gave similar results. On the other hand, on the reaction of diethyl 2-methoxy-
azulene-1,3-dicarboxylate (15), Grignard reagents attacked preferentially at the methoxy group, and 2-substituted
products were obtained. Use of excess molar equivalents of Grignard reagents led to diaryl-substituted products.
Reaction of 2-chloro-1-azaazulenes with Grignard reagents also gave similar addition–oxidation products, and
reacted at the positions in the order 8 ӷ 4 > 6, whereas reaction of 2-methoxy-1-azaazulene with a Grignard reagent
gave 1-azaazulen-2(1H)-one.
Introduction
In azulene chemistry, very few methods for introduction of
alkyl and aryl substituents are known. However, the reaction of
haloazulenes, alkoxyazulene and haloazaazulenes with some
nucleophilic reagents such as alkoxides, amines and sulfides
gave the corresponding substitution products by replacement
of the halogen or alkoxy substituent with the nucleophile.1–12
On the other hand, addition-type reactions have also been
reported for azulenes and 1-azaazulenes with some carb-
anions13–17 and 1,3-diazaazulene with Grignard reagents.18 We
have also communicated that the reactions of diethyl azulene-
1,3-dicarboxylate,19 diethyl 2-chloroazulene-1,3-dicarboxylate20
and 1-azaazulenes21 with Grignard reagents proceeded by
addition-type reaction and diethyl 2-methoxyazulene-1,3-
dicarboxylate with Grignard reagents proceeded by substitu-
tion reaction.20 We wish to report the full details herein.
Results and discussion
Diethyl azulene-1,3-dicarboxylate22 (1) was reacted with
phenylmagnesium bromide to give an unstable yellow oily mix-
ture of dihydroazulene-type addition products A. Dehydrogen-
ation of the oil A with tetrachloro-1,2-benzoquinone (TCQ)
gave three phenylazulene derivatives, diethyl 2-phenylazulene-
1,3-dicarboxylate (2a), diethyl 4-phenylazulene-1,3-dicarb-
oxylate (3a) and diethyl 6-phenylazulene-1,3-dicarboxylate (4a)
in 10%, 70% and 2% yields, respectively (Scheme 1). On alkaline
hydrolysis, followed by decarboxylation upon heating, 2a and
3a gave 2-phenylazulene23,24 (5) and 4-phenylazulene12 (6),
respectively. Deesterification of 2a with 100% phosphoric acid
Scheme 1
gave 5 together with ethyl 2-phenylazulene-1-carboxylate (7).
On the basis of this chemical evidence and the spectral data (see
Experimental), we have assigned the structures.
By careful separation of A with silica gel chromatography
with benzene, two oily compounds, diethyl 2-phenyl-1,2-
dihydroazulene-1,3-dicarboxylate (9) and diethyl 4-phenyl-1,4-
dihydroazulene-1,3-dicarboxylate (10), were isolated. In the 1H
NMR spectrum of 9, a pair of AB doublets at δ 3.45 and 4.50
DOI: 10.1039/b003078n
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This journal is © The Royal Society of Chemistry 2000
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Table 1 Reactions of azulene and 1-azaazulene derivatives with Grignard reagents and phenyl- and methyllithium
Conditions
reactant:reagents
Run
Reactant
Reagent
Product yield (%)
1
2
3
4
5
5
6
7
8
1
1
PhMgBr
α-NaphthylMgBr
CH3MgI
tBuMgBr
PhMgBr
PhMgBr
α-NaphthylMgBr
CH3MgI
tBuMgBr
PhMgBr
PhMgBr
α-NaphthylMgBr
MeMgI
PhMgBr
PhMgBr
PhMgBr
PhMgBr
PhMgBr
PhLi
1:2.5
1:2.5
1:2.5
1:2.5
1:2.5
1:1
1:2.5
1:2.5
1:2.5
1:1.5
1:3.3
1:1
2a(10) 3a(70) 4a(2)
2b(6) 3b(45) 4b(7)
2c(16) 3c(5) 4c(1) 8c(2)
3d(1) 4d(23)
12a(94) 13a(3)
12a(7) 13a (2) 11(70)
12b(76) 13b(9)
12c(20) 13c(1) 14c(2)
12d(1) 13d(30)
2a(72) 16(22)
1
1
11
11
11
11
11
15
15
15
15
2a
2c
21
25
26
1
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
17a(46) 18a(5)
2b(75) 16(10)
1:1
2c(72) 17c(2) 16(12)
17a(67) 18a(1) 19a(1)
17c(47) 19c(3)
22(5) 23(8) 24(12)
25(98)
1:2.5
1:2.5
1:2.5
1:1
1:3.5
1:3.0
1:3.0
1:3.0
1:3.0
1:2.5
1:2.5
1:1.2
1:1.2
27(85)
2a(10) 3a(70) 4a(2)
2c(70) 3c(2) 8c(3)
12c(80) 13c(2)
12c(34) 13c(2)
30(4) 31(3) 32(88)
34(8) 35(7) 36(77)
38(100)
1
MeLi
PhLi
MeLi
PhMgBr
PhMgBr
PhMgBr
PhMgBr
11
11
29
33
37
39
40(100)
and the latter is a conjugated ester signal. The mass spectrum of
9 showed its molecular peak at m/z 350, and dehydrogenation
of 9 with TCQ afforded 2a. Furthermore, the UV–vis spectrum
of 9 resembles that of ethyl heptafulvene-8-carboxylate25
†
1
(Fig. 1). The H NMR spectrum of 10 showed rather complex
features, but peaks assigned to benzylic and allylic protons were
observed at δ 3.67 (1H, br) and 4.20 (1H, br). In the IR spec-
trum of 10, two ester carbonyl peaks were observed at 1706
and 1695 cmϪ1. The maximum at the longest wavelength in the
absorption band for 10 is observed at 402 nm, and this suggests
that 10 has higher conjugated double bonds. The mass spec-
trum of 10 also showed its molecular peak at m/z 350, and
dehydrogenation of 10 with TCQ afforded 3a. From these
results the structures were assigned.
In a similar manner as with phenylmagnesium bromide, the
reaction of 1 with some other Grignard reagents, such as
α-naphthylmagnesium bromide, methylmagnesium iodide and
tert-butylmagnesium bromide, gave the corresponding substi-
tuted azulene derivatives (Scheme 1, Table 1). On the reaction
of 1 with tert-butylmagnesium bromide, no 2-substituted
product was obtained. Further, in the case of the reaction of
methylmagnesium iodide, ethyl 3-acetylazulene-1-carboxylate
(8c), which should be formed by attack of the reagent at the
ester group, was obtained along with the addition–elimination
products. Relative yields of the azulene derivatives indicate
that the bulkiness of the reagents affected the positions of
the azulene nucleus attacked, for example, the less bulky
methyl Grignard reagent gave mainly 2-substituted azulene (2c),
while the more bulky tert-butyl Grignard reagent gave mainly
6-substituted azulene (4d). These facts suggested that Grignard
reagents have a tendency to react with diethyl azulene-1,3-
dicarboxylate (1) at the positions in order of 2 > 4 > 6, while
steric hindrance has a greater influence at the positions in order
of 2 > 4 > 6.
Fig. 1 Electronic spectra of 9, 10 and ethyl heptafulvene-8-carboxyl-
ate.
Diethyl azulene-1,3-dicarboxylate (1) reacted with Grignard
reagents to give dihydroazulene-type addition products at first
as discussed above. On the other hand, it is known that
(each 1H, J 3.6) were observed, and seven-membered ring pro-
tons were seen at δ 6.0–6.4 (4H, m) and 7.62 (1H, br d, J 12.0).
In its IR spectrum, two ester carbonyl peaks were observed at
1736 and 1689 cmϪ1, the former is a non-conjugated ester signal
† The IUPAC name for ethyl heptafulvene-8-carboxylate is ethyl 2-
cyclohepta-2,4,6-trien-1-ylideneacetate.
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Scheme 2
2-haloazulenes usually react with nucleophilic reagents to give
(run 11 and 12). Furthermore, the treatment of 2a with excess
the corresponding substitution products,1,5,7 Therefore, the
reaction of Grignard reagents with azulene derivatives with a
halogen substituent capable of acting as an anionic leaving
group, were investigated in order to study substitution versus
addition reactions. Thus we treated diethyl 2-chloroazulene-
1,3-dicarboxylate22 (11) with 2.5 molar equivalents of phenyl-
magnesium bromide (run 5), and a pale yellow oily mixture
of dihydroazulene-type addition products was obtained.
Dehydrogenation of this mixture with TCQ gave two kinds of
phenylazulene derivatives, diethyl 2-chloro-4-phenyl- (12a)
(94%) and diethyl 2-chloro-6-phenylazulene-1,3-dicarboxylate
(13a) (3%). When an equimolar amount of phenylmagnesium
bromide was used, a fair amount of the starting material 11 was
recovered, accompanied by the formation of small amounts of
12a and 13a, after dehydrogenation.
Similar treatment of 11 with some other Grignard reagents,
such as α-naphthylmagnesium bromide, methylmagnesium
iodide and tert-butylmagnesium bromide, gave the correspond-
ing 4- and 6-substituted azulene derivatives (run 6–8). In
these reactions no corresponding 2-substituted products,
expected to be formed by displacement of the chloro substitu-
ent, were obtained. This indicates that in the reaction of
2-chloro derivative 11 with Grignard reagents displacement
of the chloro substituent at the 2-position did not occur, but
addition of the reagents took place at the 4- or 6-position
(Scheme 2).
molar equivalents of phenylmagnesium bromide, followed by
dehydrogenation with TCQ, gave two kinds of diphenylazulene
derivatives 17a (46%) and 18a (5%) (run 10). The same com-
pounds 17a and 18a along with a minute amount of diethyl 2,5-
diphenylazulene-1,3-dicarboxylate (19a) (run 13) were also
obtained from the reaction of 2a with phenylmagnesium
bromide. These findings showed that in the reaction of
2-methoxyazulene 15 with Grignard reagents, the reagent first
displaced the methoxy substituents at the 2-position to form the
substitution products 2a, and then the excess reagent added to
2a at the 4-, 6- or 5-position. The formation of 16 is assumed to
be caused by attack of Grignard reagents on the methyl carbon
of the methoxy group, and resembles the reaction of deprotec-
tion of aromatic ethers by Grignard reagents.26
It is known that 6-haloazulenes and 4-alkoxyazulenes also
undergo substitution with some nucleophiles.2,3,5,8 Therefore, we
next examined the reactions of 6-bromo-3,27 (21), 6-methoxy-3
(25), and 2,6-dimethoxyazulene derivatives (26) with phenyl-
magnesium bromide. In the case of 21, an addition-type
reaction proceeded and yielded 2-phenyl-derivative 22 and
4-phenyl derivative 23 together with 24 (run 15), and no sub-
stitution product was obtained. When 25 was treated with
equimolar phenylmagnesium bromide, a yellow precipitate
was produced. Decomposition of this complex by addition of
methanol and dilute hydrochloric acid gave recovered 25
quantitatively (run 16). When diethyl 2,6-dimethoxyazulene-
1,3-dicarboxylate (26) was treated with 3.5 molar equivalents of
phenylmagnesium bromide, followed by hydrolysis and dehydro-
genation with TCQ, only diethyl 6-methoxy-2-phenylazulene-
1,3-dicarboxylate (27) was obtained in 85% yield (run 17)
(Scheme 3).
On the other hand, the treatment of diethyl 2-methoxy-
azulene-1,3-dicarboxylate9 (15) with an equimolar amount of
phenylmagnesium bromide directly gave, after decompostion
of the magnesium complex thereby formed, 2-phenylazulene
derivative 2a (72%) and diethyl 2-hydroxyazulene-1,3-dicarb-
oxylate9 (16) (22%) (run 9), and the dihydroazulene-type
addition product was not obtained. Other Grignard reagents
such as α-naphthylmagnesium bromide and methylmagnesium
iodide also gave the corresponding 2-substituted products
The results showed that the displacement of 2-chloro-,
6-bromo- and 6-methoxy substituents did not occur and only
the 2-methoxy substituent could be displaced. Such a difference
in the reaction mechanism between 2-methoxy derivatives and
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Scheme 3
Scheme 4
other azulenes towards Grignard reagents may be explained
Reactions of 1 and 11 with phenyllithium and methyllithium
as follows. 1) The ethereal oxygen is much more strongly
coordinated than the halogen atoms. Therefore, in the case of
15, the Grignard reagent can easily attack at the 2-position to
form a coordination complex in which the oxygen of the
methoxy group at the 2-position is coordinated to the
reagent, whereas in the case of 11 and 21, the reagent can not
attack at the 2-position or the 6-position because of the dif-
ficulty associated with formation of the coordination com-
plex. 2) It seems that the electronic effects of the substituents
also affect the reactivities of the azulenes. The seven-
membered rings of 11 and 21 are activated to Grignard
attack by the inductive effect of the halogen substituent,
whereas 15 and 25 are deactivated by the mesomeric effect of
the methoxy group. Therefore, with 25, despite formation of
the coordination complex, the substitution reaction did not
occur. Furthermore, in the case of 25, despite the use of
excess phenylmagnesium bromide, only the substitution
reaction took place at the 2-position.
gave similar results as for Grignard reagents and gave addition–
oxidation products (run 18–21).
Like haloazulenes, 1-aza-analogues are known to react with
some nucleophiles. In addition, it has been shown that the
reaction of 2-chloro-1-azaazulenes10 (29) and ethyl 2-chloro-1-
azaazulene-3-carboxylate10 (33) with the carbanion derived
from active methylene compounds proceeds competitively to
give the substitution product or addition product, and the
reaction was highly influenced by the reaction conditions.28
Furthermore, it is known that addition reactions occur with
Grignard reagents 1,3-diazaazulene. Therefore, in the reaction
of 2-chloro-1-azaazulenes with Grignard reagents, it would be
interesting to determine which reaction, substitution or addi-
tion, occurs. For comparison of reactivity of the azulenes
and 1-azaazulenes, we next examined the reaction of 29 and 33
with Grignard reagent (run 22 and 23). Treatment of 29 and 33
with phenylmagnesium bromide, under similar conditions to
the azulenes, gave the corresponding 4-phenyl (30 and 34),
6-phenyl (31 and 35), and 8-phenyl derivatives (32 and 36), and
the reactivities were determined as C-8 ӷ C-4 > C-6 (Scheme
4). The preference for Grignard attack at the 8-position of
1-azaazulenes could be due to the coordination of the reagent
with the ring nitrogen atom. Other Grignard reagents such as
Deesterification of the derived azulene derivatives could be
carried out easily, e.g., 2,6-diphenylazulene (28) was obtained
from 18a in good yield. The reaction of azulenes with Grignard
reagents is thought, therefore, to be a favorable method for
synthesizing poly-substituted azulenes.
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styrylmagnesium bromide reacted with 1-azaazulenes to give
similar results.29
507 (2.84) and 542 (2.75) (Found: C, 75.9; H, 6.0. Calc. for
C22H20O4: C, 75.8; H, 5.8%).
On the contrary, treatment of 2-alkoxy-1-azaazulenes (37
and 39) with phenylmagnesium bromide gave 1-azaazulen-
2(1H)-ones30 (38 and 40) quantitatively (run 24 and 25). Obvi-
ously, cleavage of the O-alkyl bond must be assisted by the
coordination of the reagent to the ring nitrogen atom as shown
in B. When aryllithium was allowed to react with 6-bromo-2-
ethoxy-1-azaazulene, exclusive formation of the corresponding
4-aryl derivative was noted.17
Deesterification of diethyl 2-phenylazulene-1,3-dicarboxylate
(2a)
a) A mixture of 2a (0.050 g, 0.14 mmol) and 10% potassium
hydroxide solution (6 ml, ethanol–water = 4:1) was refluxed for
0.5 h. To the reaction mixture water was added, then the mix-
ture was neutralized with hydrochloric acid. The resultant
precipitate was collected, dried, then sublimed at 250 ЊC under
reduced pressure to give 5 (0.028 g, 96%).
b) A mixture of 2a (0.100 g, 0.29 mmol) and 100% phos-
phoric acid (2 ml) was stirred overnight at room temperature.
To the reaction mixture water was added. The mixture was
extracted with chloroform, then the extract was washed with
water, dried over sodium sulfate and evaporated. The residue
was chromatographed on silica gel. Elution with benzene gave
523,24 (0.030 g, 51%) and ethyl 2-phenylazulene-1-carboxylate
(7) (0.038 g, 48%).
Experimental
Melting points are uncorrected. H NMR spectra (60 MHz)
1
were recorded on a Hitachi Varian A-60 D spectrometer (60
MHz) and a Varian HA100 spectrometer (100 MHz) and 13C
NMR spectra were recorded on a Bruker AVANCE 400S (100.6
MHz) using deuteriochloroform as a solvent with tetramethyl-
silane as an internal standard; J values are recorded in Hz.
Electronic spectra were recorded with a Hitachi EPS-3 spectro-
photometer. IR spectra were recorded for KBr pellets on a
Shimadzu IR-27 infracord unless otherwise stated. Mass spectra
were measured with a Hitachi RMU-6 mass spectrometer at 25
eV. Kieselgel 60 and Wako-gel C-200 were used for column
chromatography.
7: Violet oil; δH 1.13 (3H, t, J 7.3), 4.40 (2H, q, J 7.3), 7.30–
7.90 (9H, m), 8.50 (1H, br d, J 10.0) and 9.97 (1H, br d, J 10.0);
νmax/cmϪ1 1688 (C᎐O) (Found: C, 75.9; H, 6.0. Calc. for C H -
᎐
22 20
O4: C, 75.8; H, 5.8%).
Deesterification of diethyl 4-phenylazulene-1,3-dicarboxylate
(3a)
Reaction of diethyl azulene-1,3-dicarboxylates with Grignard
reagents
A mixture of 3a (0.100 g, 0.29 mmol) and 10% potassium
hydroxide solution (8 ml, ethanol–water = 4:1) was refluxed for
2 h. To the reaction mixture water was added, then the mixture
was neutralized with hydrochloric acid. The resultant precipi-
tate was collected, then was sublimed at 250 ЊC under reduced
pressure to give 612 (0.050 g, 85%).
Typical procedure. Under a nitrogen atmosphere, a solution
of diethyl azulene-1,3-dicarboxylate22 1 (0.500 g, 1.84 mmol) in
dry ether (30 ml) was added to an ether solution of phenyl-
magnesium bromide, produced from bromobenzene (0.720 g,
4.58 mmol) and magnesium metal (0.110 g, 4.58 mmol) in dry
ether (30 ml), and stirred for 30 min at room temperature.
The reaction mixture was cooled on an ice-bath, and then
methanol (8 ml) and 2 M hydrochloric acid (5 ml) were
added. The mixture was extracted with benzene, and the
extract was washed with 2 M sodium hydroxide solution.
TCQ (1.0 g) was added to the solution, and the mixture was
stirred for 2 days at room temperature, then evaporated. The
residue was purified by alumina column chromatography
with chloroform as an eluant. The effluent was evaporated and
the residue was chromatographed on silica gel. Elution with
benzene gave diethyl 6-phenylazulene-1,3-dicarboxylate (4a)
(0.008 g, 2%), diethyl 2-phenylazulene-1,3-dicarboxylate (2a)
(0.077 g, 10%), and diethyl 4-phenylazulene-1,3-dicarboxylate
(3a) (0.400 g, 70%).
In a similar manner as above, we treated 1 and 11 with
α-naphthylmagnesium bromide, methylmagnesium iodide and
tert-butylmagnesium bromide. Results are listed at Table 1.
2b: Red prisms (from ethanol), 95–98 ЊC; δH 0.30 (6H, t,
J 7.3), 3.75 (4H, q, J 7.3), 7.30–8.20 (10H, m) and 9.93 (2H, br
d, J 9.0); νmax/cmϪ1 1677 (C᎐O) (Found: C, 78.6; H, 5.4. Calc.
᎐
for C26H22O4: C, 78.4; H, 5.6%).
3b: Violet prisms (from ethanol), mp 135.5–136.5 ЊC; δH 0.52
(3H, t, J 7.3), 1.43 (3H, t, J 7.3), 2.40–3.00 (1H, m), 3.20–3.70
(1H, m), 4.44 (2H, q, J 7.3), 7.30–8.10 (10H, m), 8.53 (1H, s)
and 9.99 (1H, br d, J 8.0); νmax/cmϪ1 1708 and 1688 (C᎐O); λ
᎐
max
(cyclohexane)/nm (log ε) 237 (4.45), 265 (4.42), 308 (4.46) and
550 (2.97) (Found: C, 78.5; H, 5.5. Calc. for C26H22O4: C, 78.4;
H, 5.6%).
4b: Red prisms (from ethanol), 103–104.5 ЊC; δH 1.46 (6H, t,
2a: Red prisms (from ethanol), 103–104.5 ЊC; δH 0.93 (6H, t,
J 7.0), 4.18 (4H, q, J 7.0), 7.50 (5H, br s), 7.60–8.00 (3H, m) and
9.81 (2H, d, J 10.0); δC 13.95, 60.30, 117.54, 127.13, 127.27,
129.06, 130.70, 139.09, 139.35, 140.52, 143.18, 156.21 and
J 7.1), 4.47 (4H, q, J 7.1), 7.20–8.10 (9H, m), 8.91 (1H, s) and
9.93 (2H, br d, J 9.0); νmax/cmϪ1 1680 (C᎐O); λ
(2,2,4-
᎐
max
trimethylpentane)/nm (log ε) 221 (4.98), 237 (4.62), 269 (4.44),
306 (4.69), 353 (4.38), 374 (4.27), 512 (2.83), 547 (2.75) and 595
(2.19) (Found: C, 78.3; H, 5.7. Calc. for C26H22O4: C, 78.4; H,
5.6%).
166.17; νmax/cmϪ1 1675 (C᎐O); λmax (chloroform)/nm (log ε) 235
᎐
(4.55), 269 (4.43), 305 (4.65) and 520 (2.77) (Found: C, 75.9; H,
5.9. Calc. for C22H20O4: C, 75.8; H, 5.8%).
2c: Red prisms (from ethanol), 67–67.5 ЊC; δH 1.44 (6H, t,
3a: Violet prisms (from ethanol), mp 113–114 ЊC; δH 1.08
(3H, t, J 7.0), 1.45 (3H, t, J 7.0), 3.70 (2H, q, J 7.0), 4.48 (2H, q,
J 7.0), 7.40–8.00 (8H, m), 8.72 (1H, s) and 10.45 (1H, br d,
J 10.0); δC 14.49, 14.94, 60.41, 61.13, 116.22, 122.23, 128.66,
128.87, 128.92, 129.19, 133.97, 138.91, 139.05, 139.72, 143.11,
144.04, 145.41, 153.41, 165.45 and 166.58; νmax/cmϪ1 1715 and
J 7.2), 2.96 (3H, s), 4.45 (4H, q, J 7.2), 7.30–7.70 (3H, m) and
9.37 (2H, d, J 10.0); νmax/cmϪ1 1669 (C᎐O); λmax (cyclohexane)/
᎐
nm (log ε) 238 (4.61), 269 (4.44), 296 (4.66), 307 (4.76), 346
(3.90), 355 (3.86), 373 (3.86) and 508 (2.65) (Found: C, 71.0; H,
6.2. Calc. for C17H18O4: C, 71.3; H, 6.3%).
3c: Red prisms (from ethanol), mp 66–67.5 ЊC; δH 1.44 (6H, t,
J 7.0), 3.03 (3H, s), 4.43 (4H, q, J 7.0), 7.40–7.80 (3H, m), 8.62
(1H, s) and 9.81 (1H, br d, J 11.0); νmax/cmϪ1 (chloroform) 1715
1686 (C᎐O); λ
(cyclohexane)/nm (log ε) 237 (4.45), 265
᎐
max
(4.42), 308 (4.46) and 550 (2.97) (Found: C, 75.4; H, 5.6. Calc.
for C22H20O4: C, 75.8; H, 5.8%).
and 1686 (C᎐O); λ (cyclohexane)/nm (log ε) 240 (4.45), 270
᎐
max
4a: Red prisms (from ethanol), mp 148–150 ЊC; δH 1.48 (6H,
t, J 7.3), 4.58 (4H, q, J 7.3), 7.40–7.80 (5H, m), 8.16 (2H, d,
J 12.0), 8.90 (1H, s) and 9.97 (2H, br d, J 12.0); δC 14.98, 60.47,
116.82, 129.19, 129.35, 129.49, 131.29, 138.88, 143.14, 143.60,
(4.42), 298 (4.65, sh), 305 (4.70), 342 (3.98), 372 (3.65), 424
(3.10), 515 (2.74) and 545 (2.36, sh) (Found: C, 71.2; H, 6.2.
Calc. for C17H18O4: C, 71.3; H, 6.3%).
4c: Red prisms (from ethanol), 168–169 ЊC; δH 1.47 (6H, t,
J 7.0), 2.80 (3H, s), 4.48 (4H, q, J 7.0), 7.76 (2H, d, J 11.0), 8.90
(1H, s) and 9.81 (2H, d, J 10.0); νmax/cmϪ1 1675 (C᎐O); λ
143.95, 154.98 and 165.49; νmax/cmϪ1 1681 (C᎐O); λ
(cyclo-
᎐
max
hexane)/nm (log ε) 272 (4.35), 277 (4.36), 327 (4.72), 360 (4.27),
᎐
max
J. Chem. Soc., Perkin Trans. 1, 2000, 3063–3070
3067

View Online
(cyclohexane)/nm (log ε) 234 (4.44), 270 (4.31), 292 (4.33), 298
(4.44), 303 (4.46), 308 (4.55), 336 (3.65), 343 (3.67), 366 (3.77),
378 (3.86), 465 (2.55), 500 (2.68) and 536 (2.60) (Found: C, 70.9;
H, 6.4. Calc. for C17H18O4: C, 71.3; H, 6.3%).
8c: Red prisms (from ethanol), 101–103 ЊC; δH 1.48 (3H, t,
J 7.0), 2.72 (3H, s), 4.52 (2H, q, J 7.0), 7.50–8.10 (3H, m), 8.90
(1H, s) and 9.70–10.40 (2H, m); νmax/cmϪ1 1692 and 1645
12d: Reddish violet oil; δH 1.30 (6H, t, J 7.0), 1.50 (9H, s),
4.53 (4H, q, J 7.0), 7.40–8.05 (3H, m) and 9.85 (1H, br d,
J 11.0); νmax/cmϪ1 (chloroform) 1710 and 1685 (C᎐O); 1,3,5-
᎐
trinitrobenzoate complex of 12d: reddish orange needles,
mp 122–125 ЊC (Found: C, 54.6; H, 4.4; N, 7.6. Calc. for
C26H26O10N3Cl: C, 54.2; H, 4.6; N, 7.3%)
13d: Red needles (from cyclohexane), mp 32–35 ЊC; δH 1.49
(6H, t, J 7.0), 1.49 (9H, s), 4.53 (4H, q, J 7.0), 7.94 (2H, dd,
J 10.5 and 1.0) and 9.91 (2H, dd, J 10.5 and 1.0); δC 15.40,
32.69, 39.90, 61.49, 115.66, 129.80, 130.32, 138.06, 141.55,
(C᎐O); λmax (cyclohexane)/nm (log ε) 239 (4.57), 278 (4.63), 288
᎐
(4.47), 295 (4.51), 300 (4.53), 305 (4.61), 333 (3.72), 373 (4.01),
383 (4.01), 487 (2.58), 515 (2.71) and 554 (2.64) (Found: C, 74.5;
H, 5.9. Calc. for C15H14O3: C, 74.4; H, 5.8%).
165.42 and 166.00; νmax/cmϪ1 1681 (C᎐O); λmax (2,2,4-trimethyl-
᎐
3d: Red oil; δH 0.63 (3H, t, J 7.0), 1.40 (3H, t, J 7.0), 1.58 (9H,
s), 4.06 (2H, q, J 7.0), 4.46 (2H, q, J 7.0), 7.50–8.10 (3H, m),
8.77 (1H, s) and 9.83 (1H, br d, J 10.0); νmax/cmϪ1 (chloroform)
pentane)/nm (log ε) 236 (4.54), 263 (4.30), 271 (4.38), 302 (4.71),
312 (4.79), 357 (4.00), 373 (3.73), 489 (2.79) and 507 (2.75);
1,3,5-trinitrobenzoate complex of 13d: reddish orange needles,
mp 142.5–143 ЊC (Found: C, 54.4; H, 4.5; N, 7.3. Calc. for
C26H26O10N3Cl: C, 54.2; H, 4.6; N, 7.3%).
1710 and 1680 (C᎐O) (Found: C, 72.8; H, 7.3. Calc. for
᎐
C20H24O4: C, 73.1; H, 7.4%).
4d: Red prisms (from ethanol), 100–101 ЊC; δH 1.31 (6H, t,
J 7.0), 1.52 (9H, s), 4.52 (4H, q, J 7.0), 8.07 (2H, d, J 11.0), 8.95
(1H, s) and 9.91 (2H, br d, J 11.0); δC 14.99, 32.25, 39.43, 60.34,
Preparation and isolation of dihydroazulenes
Under a nitrogen atmosphere, a solution of 1 (1.000 g, 3.67
mmol) in dry ether (50 ml) was added to an ether solution of
phenylmagnesium bromide, produced from bromobenzene
(1.440 g, 9.17 mmol) and magnesium metal (0.223 g, 9.17
mmol) in dry ether (50 ml), and stirred for 30 min at room
temperature. The reaction mixture was cooled on a ice-bath,
and then methanol (8 ml) and 2 M hydrochloric acid (5 ml)
was added. The mixture was extracted with ether, then the
extract was washed with water, dried over sodium sulfate
and evaporated. The residue was separated rapidly by silica
gel (Wako-gel C-200) chromatography. Elution of benzene
gave diethyl 4-phenyl-1,4-dihydroazulene-1,3-dicarboxylate
(10) (0.900 g, 70%) and diethyl 2-phenyl-1,2-dihydroazulene-
1,3-dicarboxylate (9) (0.210 g, 16%).
9: Yellow oil, δH 0.98 (3H, t, J 7.0), 1.28 (3H, t, J 7.0),
3.45(1H, d, J 3.6), 3.98 (2H, q, J 7.0), 4.25 (2H, q, J 7.0), 4.50
(1H, d, J 3.6), 6.00–6.40 (4H, m), 7.13 (5H, br s) and 7.62 (1H,
br d, J 12.0); νmax/cmϪ1 (neat) 1736 and 1689 (C᎐O); λ
(methanol)/nm (log ε) 365 (4.20) and 440 (3.38); Mass m/z 350
(Mϩ) (Found: C, 75.6; H, 6.4. Calc. for C22H22O4: C, 75.4; H,
6.3%).
116.10, 128.73, 129.26, 138.59, 143.18, 165.58 and 165.99; νmax
/
cmϪ1 1681 (C᎐O); λmax (cyclohexane)/nm (log ε) 235 (4.61), 290
᎐
(4.53), 308 (4.78), 337 (3.40), 342 (3.90), 365 (3.99), 374 (4.06),
497 (2.83), 532 (2.76) and 580 (2.25) (Found: C, 73.2; H, 7.5.
Calc. for C20H24O4: C, 73.1; H, 7.4%).
12a: Violet needles (from ethanol), mp 108–109 ЊC; δH 1.12
(3H, t, J 7.0), 1.47 (3H, t, J 7.0), 3.60 (2H, q, J 7.0), 4.51 (2H, q,
J 7.0), 7.46 (5H, br s), 7.40–8.00 (3H, m) and 9.54–9.80 (1H, m);
δC 14.27, 14.82, 61.04, 61.51, 114.49, 122.24, 128.61, 129.04,
129.07, 129.55, 134.32, 136.01, 138.58, 138.74, 141.21, 141.72,
143.69, 152.01, 164.75 and 165.51; νmax/cmϪ1 1718 and 1695
(C᎐O); λmax (2,2,4-trimethylpentane)/nm (log ε) 238 (4.35), 269
᎐
(4.18), 300 (4.56), 309 (4.57), 355 (3.80), 530 (2.74) and 550
(2.74) (Found: C, 69.5; H, 5.0. Calc. for C22H19O4Cl: C, 69.2;
H, 5.0%).
13a: Red prisms (from ethanol), 138–139 ЊC; δH 1.49 (6H, t,
J 7.0), 4.53 (4H, q, J 7.0), 7.40–7.80 (5H, m), 7.94 (2H, dd,
J 10.3 and 1.5) and 9.57 (2H, dd, J 10.3 and 1.5); δC 14.99,
60.47, 116.82, 129.09, 129.35, 129.49, 131.29, 138.89, 143.14,
143.60, 143.95, 154.99 and 165.49; νmax/cmϪ1 1686 (C᎐O); λ
᎐
max
᎐
max
(2,2,4-trimethylpentane)/nm (log ε) 237 (4.54), 270 (4.19), 325
(4.75), 366 (4.24), 502 (2.81) and 528 (2.77) (Found: C, 69.1;
H, 5.1. Calc. for C22H19O4Cl: C, 69.2; H, 5.0%).
10: Yellow oil, δH 1.28 (3H, t, J 7.0), 1.30 (3H, t, J 7.0), 3.67
(1H, br s), 4.20 (1H, br s), 4.25 (2H, q, J 7.0), 4.27 (2H, q, J 7.0),
5.80–6.40 (3H, m), 6.90–7.30 (6H, m) and 7.50 (1H, br d,
12b: Red violet needles (from ethanol), mp 124–125 ЊC;
δH 0.61 (3H, t, J 7.1), 1.47 (3H, t, J 7.1), 2.40–3.00 (1H, m),
3.20–3.80 (1H, m), 4.52 (2H, q, J 7.1), 7.30–8.10 (10H, m) and
9.93 (1H, br d, J 10.0); νmax/cmϪ1 1720 and 1683 (C᎐O); λ
J 12.0); νmax/cmϪ1 (neat) 1706 and 1695 (C᎐O); λ
(2,2,4-
᎐
max
trimethylpentane)/nm (log ε) 360 (3.94) and 402 (3.90); Mass
m/z 350 (Mϩ) (Found: C, 75.7; H, 6.5. Calc. for C22H22O4: C,
75.4; H, 6.3%).
᎐
max
(chloroform)/nm (log ε) 300 (4.61), 310 (4.69), 335 (4.00, sh) and
542 (3.05) (Found: C, 72.4; H, 4.5. Calc. for C26H21O4Cl: C, 72.1;
H, 4.9%).
Dehydration of diethyl 2-phenyl-1,2-dihydroazulene-1,3-dicarb-
oxylate (9)
13b: Red needles (from ethanol), 143–145 ЊC; δH 1.50 (6H, t,
J 7.0), 4.57 (4H, q, J 7.0), 7.40–8.20 (9H, m) and 9.77 (2H, br d,
A solution of 9 (0.042 g, 0.093 mmol) and TCQ (50 mg, 0.20
mmol) in benzene (10 ml) was refluxed for 1 h. The mixture was
washed with 4% potassium hydroxide and water, dried over
sodium sulfate, and evaporated. Chromatography of the resi-
due on silica gel–benzene gave diethyl 2-phenylazulene-1,3-
dicarboxylate 2a (0.021 g, 50%).
J 12.0); νmax/cmϪ1 1678 (C᎐O); λmax (chloroform)/nm (log ε) 265
᎐
(4.35), 309 (4.58), 350 (4.21), 375 (4.10) and 535 (2.82) (Found:
C, 71.9; H, 5.1. Calc. for C26H21O4Cl: C, 72.1; H, 4.9%).
12c: Red prisms (from ethanol), mp 79.5–81 ЊC; δH 1.44
(3H, t, J 7.2), 1.46 (3H, t, J 7.2), 2.90 (3H, s), 4.49 (2H, q,
J 7.2), 4.51 (2H, q, J 7.2), 7.40–7.90 (3H, m) and 9.60 (1H, br d,
J 10.0); νmax/cmϪ1 (chloroform) 1723 and 1676 (C᎐O); λ
Dehydration of diethyl 4-phenyl-1,4-dihydroazulene-1,3-dicarb-
oxylate (10)
᎐
max
(2,2,4-trimethylpentane)/nm (log ε) 240 (4.50), 296 (4.71), 305
(4.73), 353 (4.01), 370 (3.72), 508 (2.83), 533 (2.80) and 577
(2.44) (Found: C, 63.4; H, 5.3. Calc. for C17H17O4Cl: C, 63.6;
H, 5.3%).
A solution of 10 (0.200 g, 0.57 mmol) and TCQ (250 mg, 1.08
mmol) in xylene (8 ml) was refluxed for 2 h, then evaporated.
Chromatography of the residue on alumina–benzene gave
diethyl 4-phenylazulene-1,3-dicarboxylate (3a) (0.090 g, 36%).
13c: Red prisms (from ethanol), 57–61 ЊC; δH 1.48 (6H, t,
J 7.3), 2.80 (3H, s), 4.55 (4H, q, J 7.3), 7.76 (2H, d, J 11.0) and
9.81 (2H, d, J 11.0); νmax/cmϪ1 1675 (C᎐O) (Found: C, 63.3; H,
᎐
Reaction of diethyl 2-methoxyazulene-1,3-dicarboxylate (15)
with Grignard reagents
5.2. Calc. for C17H17O4Cl: C, 63.6; H, 5.3%).
14c: Red prisms (from cyclohexane), 88–90 ЊC; δH 1.47 (3H, t,
J 7.0), 2.74 (3H, s), 4.50 (2H, q, J 7.0), 7.50–8.10 (3H, m) and
Typical procedure. a) Under a nitrogen atmosphere, a solu-
tion of 15 (1.000 g, 3.31 mmol) in dry ether (30 ml) was added
to an ether solution of phenylmagnesium bromide, produced
9.70–10.40 (2H, m); νmax/cmϪ1 1695 and 1645 (C᎐O) (Found:
᎐
C, 65.3; H, 4.8. Calc. for C15H13O3Cl: C, 65.1; H, 4.7%).
3068
J. Chem. Soc., Perkin Trans. 1, 2000, 3063–3070

View Online
from bromobenzene (0.800 g, 5.10 mmol) and magnesium
metal (0.120 g, 4.94 mmol) in dry ether (50 ml), at Ϫ20 ЊC, and
then stirred for 30 min at room temperature. To the reaction
mixture, methanol (8 ml) and 2 M hydrochloric acid (5 ml) were
added. The mixture was extracted with benzene, then the
extract was evaporated. The residue was chromatographed on
silica gel. Elution with benzene gave diethyl 2-phenylazulene-
1,3-dicarboxylate (2a) (0.826 g, 72%). Elution with chloroform
gave diethyl 2-hydroxyazulene-1,3-dicarboxylate9 (16) (0.241 g,
22%).
b) Under a nitrogen atmosphere, a solution of 15 (1.000 g,
3.31 mmol) in dry ether (30 ml) was added to an ether solution
of phenylmagnesium bromide, produced from bromobenzene
(1.820 g, 11.6 mmol) and magnesium metal (0.282 g, 11.6
mmol) in dry ether (50 ml), and stirred for 30 min at room
temperature. The reaction mixture was cooled on ice-bath, and
then methanol (15 ml) and 2 M hydrochloric acid (10 ml) were
added. The mixture was extracted with benzene, then the
extract was washed with 2 M sodium hydroxide solution. TCQ
(2.0 g) was added to the solution, and stirred for 2 days at room
temperature. The mixture was evaporated, and the residue was
purified by alumina column chromatography with chloroform
as an eluant. The effluent was evaporated and the residue was
chromatographed on silica gel. Elution with benzene gave
diethyl 2,6-diphenylazulene-1,3-dicarboxylate (18a) (0.065 g,
5%) and diethyl 2,4-diphenylazulene-1,3-dicarboxylate (17a)
(0.645 g, 46%).
J 11.5); νmax/cmϪ1 3250 (OH), 1728, 1688 and 1668 (C᎐O); λ
᎐
max
(cyclohexane)/nm (log ε) 242 (4.55), 268 (4.52), 306 (4.85, sh),
316 (4.85), 358 (4.17, sh), 518 (2.80) and 542 (2.78, sh) (Found:
C, 46.7; H, 2.7. Calc. for C28H19O6Cl4Br: C, 47.0; H, 2.9%).
27: Orange needles (from ethanol), mp 126–127 ЊC; δH 0.91
(6H, t, J 7.1), 4.02 (3H, s), 4.11 (4H, q, J 7.1), 7.29 (2H, dm,
J 12.0), 7.38 (5H, br s) and 9.54 (2H, dm, J 12.0); νmax/cmϪ1
1668 (C᎐O); λmax (cyclohexane)/nm (log ε) 234 (4.32), 265 (4.22,
᎐
sh), 273 (4.30), 313 (4.69, sh), 325 (4.77), 353 (4.05), 362 (4.04),
380 (3.70), 470 (2.87) and 495 (2.80, sh) (Found: C, 73.2; H, 5.9.
Calc. for C23H22O5: C, 72.7; H, 5.9%).
Deesterification of diethyl 2,6-diphenylazulene-1,3-dicarboxylate
(18a)
A mixture of 18a (0.030 g, 0.071 mmol) and 100% phosphoric
acid (2 ml) was heated at 100 ЊC for 1 h. To the reaction mix-
ture water was added. The mixture was extracted with chloro-
form, then the extract was washed with water, dried over
sodium sulfate and evaporated. The residue was chromato-
graphed on alumina. Elution with benzene gave 2,6-diphenyl-
azulene 28 (0.016 g, 81%).
28: Blue needles (from ethanol), mp 212–213.5 ЊC; δH 7.30–
8.00 (12H, m), 8.43 (2H, d, J 10.0) and 9.20 (2H, d, J 10.0); νmax
/
cmϪ1 760, 694 and 685 (phenyl); λmax (chloroform)/nm (log ε)
319 (4.89), 366 (3.90), 380 (4.00), 395 (4.08), 580 (2.60), 623
(2.60) and 680 (2.27) (Found: C, 93.5; H, 5.9. Calc. for C22H16:
C, 93.3; H, 5.7%).
17a: Violet prisms (from ethanol), mp 113–114.5 ЊC; δH 0.75
(3H, t, J 7.3), 0.94 (3H, t, J 7.3), 3.34 (2H, q, J 7.3), 4.15 (2H, q,
J 7.3), 7.36 (5H, br s), 7.40–7.90 (8H, m) and 9.78 (1H, dd,
Reaction of diethyl azulene-1,3-dicarboxylates with phenyl and
methyllithium
J 10.5 and 2.5); νmax/cmϪ1 1716 and 1681 (C᎐O); λ
(2,2,4-
᎐
max
trimethylpentane)/nm (log ε) 231 (4.40), 272 (4.31), 314 (4.60),
355 (3.96), 538 (2.89), 565 (2.89) and 615 (2.53) (Found: C, 78.9;
H, 5.8. Calc. for C28H24O4: C, 79.2; H, 5.7%).
Typical procedure. Under a nitrogen atmosphere, a solution
of diethyl azulene-1,3-dicarboxylate 1 (0.200 g, 0.73 mmol) in
dry ether (30 ml) was added to an ether solution of phenyl-
lithium, produced from bromobenzene (0.344 g, 2.19 mmol)
and lithium metal (0.030 g, 4.33 mmol) in dry ether (30 ml),
and stirred for 30 min at room temperature. The reaction
mixture was cooled on a ice-bath, and then methanol (8 ml)
was added. TCQ (0.500 g) was added to the solution, and the
solution was stirred overnight at room temperature. The solu-
tion was washed with 4% potassium hydroxide and water, dried
over sodium sulfate, and evaporated. The residue was chrom-
atographed on silica gel. Elution with benzene gave diethyl
6-phenylazulene-1,3-dicarboxylate (4a) (0.003 g, 2%), diethyl
2-phenylazulene-1,3-dicarboxylate (2a) (0.028 g, 10%), and
diethyl 4-phenylazulene-1,3-dicarboxylate (3a) (0.190 g, 70%).
In a similar manner, we treated 1 and 11 with phenyllithium
and methyllithium. Results are listed in Table 1.
18a: Red prisms (from ethanol), mp 188–189 ЊC; δH 0.93 (6H,
t, J 7.3), 4.09 (4H, q, J 7.3), 7.37 (5H, br s), 7.40–7.80 (5H, m),
7.93 (2H, dd, J 10.5 and 1.0) and 9.81 (2H, dd, J 10.5 and 1.0);
νmax/cmϪ1 1673 (C᎐O); λ (chloroform)/nm (log ε) 260 (4.01),
᎐
max
278 (4.14), 332 (4.73), 368 (4.19) and 507 (2.79) (Found: C, 79.0;
H, 5.7. Calc. for C28H24O4: C, 79.2; H, 5.7%).
In a similar manner, reactions of 2a, 2c, 21, 25 and 26 with
some Grignard reagents were performed (Table 1).
19a: Red prisms (from ethanol), mp 178–180 ЊC; δH 0.93 (6H,
t, J 7.2), 4.11 (4H, q, J 7.2), 7.40 (5H, br s), 7.30–8.20 (7H, m),
9.55–9.85 (1H, m) and 9.99 (1H, d, J 2.0); νmax/cmϪ1 1685 (C᎐O)
᎐
(Found: C, 79.0; H, 5.8. Calc. for C28H24O4: C, 79.2; H, 5.7%).
17c: Violet prisms (from ethanol), mp 109.5–110.5 ЊC; δH 1.08
(3H, t, J 7.1), 1.46 (3H, t, J 7.1), 2.78 (3H, s), 3.52 (2H, q, J 7.1),
4.49 (2H, q, J 7.1), 7.48 (5H, br s), 7.30–7.70 (3H, m) and 9.62–
9.87 (1H, m); νmax/cmϪ1 1698 and 1684 (C᎐O); λ
(cyclo-
᎐
max
Reaction of 2-chloro-1-azaazulenes with Grignard reagents
hexane)/nm (log ε) 236 (4.30), 270 (4.30), 295 (4.43, sh), 309
(4.52), 357 (3.77), 378 (3.55), 540 (2.81) and 610 (2.33, sh)
(Found: C, 75.9; H, 6.2. Calc. for C23H22O4: C, 76.2; H, 6.1%).
19c: Red prisms (from ethanol), mp 95–96 ЊC; δH 1.49 (6H, t,
J 7.3), 3.10 (3H, s), 4.55 (4H, q, J 7.3), 7.30–8.20 (7H, m), 9.53
Typical procedure. Under a nitrogen atmosphere, a solution
of 2-chloro-1-azaazulene (29) (1.000 g, 6.12 mmol) in dry THF
(30 ml) was added to a solution of phenylmagnesium bromide,
produced from bromobenzene (2.400 g, 15.30 mmol) and mag-
nesium metal (0.372 g, 15.30 mmol) in dry THF (30 ml), and
stirred for 30 min at room temperature. The reaction mixture
was cooled on a ice-bath, and then methanol (8 ml) and 2 M
hydrochloric acid (6 ml) were added. To the mixture water (150
ml) was added, and the mixture was extracted with chloroform.
To the extract TCQ (2.00 g) was added, and the mixture was
stirred for 3 h at room temperature, then evaporated. The resi-
due was subjected to alumina column chromatography with
chloroform as an eluant. The effluent was evaporated and
the residue was chromatographed on silica gel. Elution with
benzene gave 2-chloro-8-phenyl-1-azaazulene (32) (1.285 g,
88%), 2-chloro-6-phenyl-1-azaazulene (31) (0.050 g, 3%), and
2-chloro-4-phenyl-1-azaazulene (30) (0.057 g, 4%).
(1H, d, J 10.5) and 9.91 (1H, d, J 10.5); νmax/cmϪ1 1685 (C᎐O)
᎐
(Found: C, 76.0; H, 5.8. Calc. for C23H22O4: C, 76.2; H, 6.1%).
22: Red prisms (from ethanol), mp 185–187 ЊC; δH 0.90 (6H,
t, J 7.0), 4.07 (4H, q, J 7.0), 7.28 (5H, br s), 7.93 (2H, d, J 11.4)
and 9.25 (2H, d, J 11.4); νmax/cmϪ1 1672 (C᎐O) (Found: C, 61.8;
᎐
H, 4.6. Calc. for C21H19O4Br: C, 61.7; H, 4.5%).
23: Red prisms (from ethanol), mp 188–189 ЊC; δH 1.07 (3H,
t, J 7.3), 1.44 (3H, t, J 7.1), 3.65 (2H, q, J 7.3), 4.44 (2H, q,
J 7.1), 7.53 (5H, br s), 7.94 (H, d, J 10.3), 8.03 (1H, s), 8.63 (1H,
s) and 9.68 (1H, d, J 10.3); νmax/cmϪ1 1705 and 1697 (C᎐O)
᎐
(Found: C, 61.9; H, 4.5. Calc. for C21H19O4Br: C, 61.7; H,
4.5%).
24: Red plates (from ethanol), mp 201.5–202.5 ЊC; δH 0.93
(3H, t, J 7.2), 1.29 (3H, t, J 7.2), 3.24 (2H, q, J 7.2), 4.35 (2H, q,
J 7.2), 7.48 (5H, br s), 7.45–8.05 (2H, m) and 9.10 (1H, d,
30: Reddish orange needles (from hexane), 120–121 ЊC;
δH 6.97 (1H, s), 7.40–7.60 (5H, m), 7.64–7.98 (3H, m) and 8.59
J. Chem. Soc., Perkin Trans. 1, 2000, 3063–3070
3069

View Online
(1H, dm, J 9.0); νmax/cmϪ1 798, 775, 745 and 695 (phenyl); λmax
(methanol)/nm (log ε) 228 (3.76), 275 (4.68), 308 (3.73, sh), 337
(3.75) and 470 (3.37) (Found: C, 75.4; H, 4.2; N, 5.7. Calc. for
C15H10NCl: C, 75.2; H, 4.3; N, 5.7%).
References
1 T. Nozoe, S. Seto and S. Matsumura, Bull. Chem. Soc. Jpn.,
1962, 35, 1990; S. Matsumura, Chem. Pharm. Bull., 1962, 10,
1024.
31: Reddish orange prisms (from hexane), mp 137.5–
138.5 ЊC; δH 7.17 (1H, s), 7.40–7.70 (5H, m), 7.81 (1H, dd,
J 10.8 and 1.8), 7.92 (1H, dd, J 10.2 and 1.8), 8.40 (1H, d,
J 10.8) and 8.55 (1H, d, J 10.2); νmax/cmϪ1 847, 775, 760 and 698
(phenyl); λmax (methanol)/nm (log ε) 226 (3.24), 273 (4.58), 307
(4.39), 346 (4.12), 361 (4.15) and 576 (3.36) (Found: C, 75.6; H,
4.2; N, 5.8. Calc. for C15H10NCl: C, 75.2; H, 4.3; N, 5.7%).
32: Reddish orange needles (from cyclohexane), 123–124 ЊC;
2 K. Hafner, H. Patzelt and H. Kaiser, Liebigs Ann. Chem., 1962, 656,
24.
3 T. Nozoe, K. Takase and M. Tada, Bull. Chem. Soc. Jpn., 1965, 38,
247; M. Tada, Bull. Chem. Soc. Jpn., 1966, 39, 1954.
4 R. N. McDonald and J. M. Richmond, J. Org. Chem., 1975, 40,
1689; R. N. McDonald, J. M. Richmond, J. R. Curtis and T. L.
Hoskins, J. Org. Chem., 1976, 41, 1811.
5 S. Kosuge, T. Morita and K. Takase, Chem. Lett., 1975, 733.
6 T. Morita, F. Ise and K. Takase, Chem. Lett., 1982, 1303.
7 T. Morita, T. Fujita and T. Nakadate, Sci. Rep. Tohoku Univ., Ser. 1,
1980, 62, 92 (Chem. Abstr. 1981, 94, 83832).
8 D. H. Reid, W. H. Stafford and J. P. Ward, J. Chem. Soc., 1958,
1100.
9 T. Nozoe, K. Takase and N. Shimazaki, Bull. Chem. Soc. Jpn., 1964,
37, 1644.
δH 7.18 (1H, s), 7.30–7.90 (8H, m) and 8.40 (1H, d, J 9.7); νmax
/
cmϪ1 797, 747, 732 and 690 (phenyl); λmax (methanol)/nm (log ε)
223 (3.80), 268 (4.51), 292 (4.24), 338 (3.74) and 468 (3.44)
(Found: C, 75.5; H, 4.1; N, 5.9. Calc. for C15H10NCl: C, 75.2; H,
4.3; N, 5.7%).
10 T. Nozoe, S. Seto, S. Matsumura and T. Terasawa, Chem. Ind.
(London), 1954, 1357.
11 T. Toda, S. Seto and T. Nozoe, Bull. Chem. Soc. Jpn., 1968, 41, 2102.
12 K. Hafner and Weldes, Liebigs Ann. Chem., 1957, 606, 90.
13 T. Nishiwaki and N. Abe, Heterocycles, 1981, 15, 547.
14 K. Hafner, C. Bernhard and R. Müller, Liebigs Ann. Chem., 1961,
650, 35.
In a similar manner, we treated ethyl 1-azaazulene-3-
carboxylate (33) with phenylmagnesium bromide. Results are
listed in Table 1.
34: Orange prisms (from hexane), 115.5–116.5 ЊC; δH 1.06
(3H, t, J 7.0), 3.59 (2H, q, J 7.0), 7.43 (5H, m), 7.60–8.03 (3H,
m) and 865 (1H, d, J 10.0); νmax/cmϪ1 1703 (C᎐O), 790, 755, 742
᎐
15 R. N. McDonald, H. E. Petty, N. L. Wolfe and J. V. Paukstelis,
J. Org. Chem., 1974, 39, 1877.
16 T. Morita, T. Fujita and K. Takase, Tetrahedron Lett., 1974, 2585.
17 G. Sunagawa and M. Watatani, Chem. Pharm. Bull., 1968, 16,
1308.
18 T. Mukai, H. Tsuruta and Momotari, Bull. Chem. Soc. Jpn., 1967,
40, 1967.
19 N. Abe, T. Morita and K. Takase, Tetrahedron Lett., 1973, 3883.
20 N. Abe and K. Takase, Tetrahedron Lett., 1973, 4739.
21 N. Abe, Heterocycles, 1976, 4, 221.
22 T. Nozoe, S. Seto, S. Matsumura and T. Asano, Proc. Jpn. Acad.,
1956, 32 339.
23 Pl. A. Plattner, R. Sandrin and J. Wyss, Helv. Chim. Acta, 1946, 29,
1604; Pl. A. Plattner, A. Fürst, M. Gordon and K. Zimmermann,
Helv. Chim. Acta, 1950, 33, 1910.
24 T. Nozoe, K. Takase and S. Fukuda, Bull. Chem. Soc. Jpn., 1971, 44,
2210.
25 M. Oda and Y. Kitahara, Chem. Ind. (London), 1969, 920.
26 K. Sisido and H, Nozaki, J. Am. Chem. Soc., 1948, 70, 884; P. W.
Tucker, J. Am. Chem. Soc., 1949, 71, 2584.
and 700 (phenyl); λmax (methanol)/nm (log ε) 230 (4.32), 283
(4.68), 337 (3.89) and 468 (3.44) (Found: C, 69.9; H, 4.5; N, 4.5.
Calc. for C18H14NOCl: C, 70.0; H, 4.5; N, 4.5%).
35: Yellow needles (from hexane), mp 167–169 ЊC; δH 1.50
(3H, t, J 7.2), 4.49 (2H, q, J 7.2), 7.40–7.65 (5H, m), 8.13 (2H,
dd, J 10.3 and 1.5), 8.19 (1H, dd, J 10.3 and 1.5) and 9.55 (1H,
dd, J 10.3 and 1.5); νmax/cmϪ1 1680 (C᎐O), 852, 770, 743 and 685
᎐
(phenyl); λmax (methanol)/nm (log ε) 283 (4.49, sh), 298 (4.55),
313 (4.57), 345 (4.34), 361 (4.36) and 443 (3.34) (Found: C, 69.8;
H, 4.4; N, 4.5. Calc. for C18H14NOCl: C, 70.0; H, 4.5; N, 4.5%).
36: Yellow needles (from cyclohexane), 154–155.5 ЊC; δH 1.47
(3H, t, J 7.0), 4.46 (2H, q, J 7.0), 7.36–8.06 (8H, m) and 9.58
(1H, dm, J 9.5); νmax/cmϪ1 1684 (C᎐O), 797, 765, 747 and 692
᎐
(phenyl); λmax (methanol)/nm (log ε) 279 (4.56), 300 (4.42, sh),
338 (4.01, sh) and 447 (3.20) (Found: C, 69.7; H, 4.5; N, 4.6.
Calc. for C18H14NOCl: C, 70.0; H, 4.5; N, 4.5%).
27 R. N. McDonald, D. L. Morris, H. E. Petty and T. L. Hoskins,
J. Chem. Soc., Chem. Commun, 1971, 743.
28 N. Abe and T. Nishiwaki, Bull. Chem. Soc. Jpn., 1978, 51, 667.
29 N. Abe and T. Nishiwaki, Bull. Chem. Soc. Jpn., 1980, 53, 1406.
30 T. Nozoe, S. Seto, S. Matsumura and T. Terasawa, Chem. Ind.
(London), 1954, 1356.
Acknowledgements
This research has been financially supported by grants of the
Japanese Ministry of Education and the Takeda Science
Foundation.
3070
J. Chem. Soc., Perkin Trans. 1, 2000, 3063–3070