Reaction of phenylhydrazines with arenes in the presence of aluminium trichloride

Article abstract of DOI:10.1039/b103802h

Phenylnitrenium ions are generated from phenylhydrazines by treatment with AlCl₃. Reaction of a phenylnitrenium ion with arenes results in both aromatic N-substitution and C-substitution. In contrast, an N-methylphenylnitrenium ion undergoes exclusively aromatic C-substitution. Reaction of a phenylnitrenium ion with arenes present only in slight excess produces anilinated products in moderate to good yields.

Full text of DOI:10.1039/b103802h

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Reaction of phenylhydrazines with arenes in the presence of
aluminium trichloride
Atsushi Ohwada, Shigeru Nara, Takeshi Sakamoto and Yasuo Kikugawa*
1
Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado,
Saitama 350-0295, Japan
Received (in Cambridge, UK) 26th April 2001, Accepted 27th September 2001
First published as an Advance Article on the web 29th October 2001
Phenylnitrenium ions are generated from phenylhydrazines by treatment with AlCl . Reaction of a phenylnitrenium
3
ion with arenes results in both aromatic N-substitution and C-substitution. In contrast, an N-methylphenylnitrenium
ion undergoes exclusively aromatic C-substitution. Reaction of a phenylnitrenium ion with arenes present only in
slight excess produces anilinated products in moderate to good yields.
Introduction
Generally, a phenylnitrenium ion has canonical resonance
forms in which the positive charge populates the ortho- and
para-positions as well as the nitrogen atom. Therefore, one can
expect the formation of three kinds of products, ortho- and
para-aminobiaryls and N,N-diarylamine. Takeuchi and Takano
reported that a phenylnitrenium ion generated by the action of
strong acid (TFA or TFSA) on phenyl azide preferentially
The chemistry of nitrenium ions has received considerable
attention with respect to synthetic, theoretical, and biological
considerations. In spite of the several potential uses of aryl-
1
2
nitrenium ions, methods for their generation are limited.
Examples of reactions that involve phenylnitrenium ions
as intermediates include the following. Parish and Whiting
reported tetrafluoroboric acid-catalyzed phenylamination of
arenes with phenylhydroxylamine. Takeuchi et al. have found
that phenyl azide reacts with arenes in the presence of trifluoro-
11
undergoes N-substitution to give N,N-diarylamine. On the
other hand, a phenylnitrenium ion generated by the action of6
3
strong acid on 1a undergoes both C- and N-substitution.
Likewise, AlCl -mediated decomposition of 1a in solvent arenes
4
a
4b
3
acetic acid (TFA) or aluminium trichloride. Olah et al. have
reported the acid-catalyzed reactions of phenyl azide with triflic
brought about essentially the same results. In contrast, it
is noteworthy that an N-methylphenylnitrenium ion formed
by reaction of N-methyl-N-phenylhydrazine 1b with AlCl3
undergoes exclusively aromatic C-substitution to give biphenyl
derivatives 6a–d, 7a–c (Table 1, entries 6–9).
5
acid (TFSA). Shudo and co-workers have reported that phenyl-
hydrazine reacts with benzene in the presence of TFA and
TFSA to give aminobiphenyls. Recently, an arylnitrenium ion
has been generated by photolysis of 1-anilino-pyridinium and
6
7
-
quinolinium salts.
Reaction of phenylhydrazines with 1–2 molar excess of arenes in
the presence of AlCl3
We have reported that the reaction of N-(arylamino)phthal-
imide derivatives with AlCl in benzene produces aminobiaryls
and N,N-diarylamines. The formation of an arylnitrenium ion
was suggested to account for the production of these products.
In an extension of this work, we investigated the reaction of
phenylhydrazine 1a with AlCl3 in the presence of arenes.
Compound 1a has been shown previously to decompose upon
heating in the presence of Lewis acids to give aniline, benzene,
ammonia, and other products. In a molten mixture of AlCl –
3
8
The hitherto reported reactions of phenylnitrenium ion with
arenes are limited to the cases where large excesses of arenes are
used as solvent. However, it would be useful to develop an
equimolar coupling reaction of nitrenium ions with arenes, in
particular in cases where the arene is difficult to prepare. In this
context, we have investigated the ability of solvents to stabilize
a nitrenium ion that would allow further coupling reactions.
Initially, we investigated the reaction of 1a with 1.1 molar
9
3
NaCl–KCl, 1a gives o-phenylenediamine (30%) and aniline
10
equiv. of naphthalene in the presence of AlCl in nitromethane.
(
30%).
3
The phenylnitrenium ion generated from 1a attacked the
α-position of naphthalene to give N-(naphthalen-1-yl)aniline
2f in 47% yield along with unidentified products (Scheme 2).
Results and discussion
(
CF ) CHOH (HFIP) is known to have a high ionizing power
3 2
12
Reaction of phenylhydrazines with solvent arenes in the presence
of AlCl3
and low nucleophilicity, and might stabilize a nitrenium ion
for an equimolar coupling reaction. Indeed, changing the
solvent from CH NO to CH NO –HFIP (1 : 1) raised the yield
Treatment of 1a with AlCl (5 mol eq.) in benzene for 1 h
3
3
2
3
2
at room temperature gave diphenylamine 2a and 2-amino- and
of 2f to 78%. Based on these results, HFIP alone or mixed with
other solvents was used in our subsequent examination of
coupling reactions with other arenes. The results are presented
in Table 2.
4
-amino-biphenyl (3, 4a) (Scheme 1). The formation of these
products indicates that AlCl -mediated heterolytic cleavage
3
of the N–N bond produced a phenylnitrenium ion and that
canonical forms involving the benzene ring were trapped by
benzene to give the products. It is interesting to note that
Takeuchi et al. have reported that reaction of phenyl azide
with TFA produces a phenylnitrenium ion that reacts with a
large excess of naphthalene to afford 2f in 41% yield. If the
nitrenium ion is generated with TFSA the yield is raised to
1
a, despite having no nucleofugal substituent on nitrogen, can
be converted to a phenylnitrenium ion under mild reaction
conditions.
4,11
78%.
In our case, the same N-substitution product 2f was
Reaction of several benzene derivatives with 1a by this
procedure gave the results presented in Table 1.
obtained in 78% yield using 1.1 molar excess of naphthalene.
The yields are isolated yields based on 1a consumed.
3
064
J. Chem. Soc., Perkin Trans. 1, 2001, 3064–3068
This journal is © The Royal Society of Chemistry 2001
DOI: 10.1039/b103802h

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Scheme 1
Table 1 AlCl -mediated decomposition of 1a–d in solvent arenes at room temperature
3
Entry
Reagent
Solvent
Conditions
Product (yield, %)
1
2
3
4
5
6
7
8
9
1a
1a
1a
1a
1a
1b
1b
1b
1b
benzene
rt, 1 h
rt, 2.5 h
rt, 3 h
rt, 3 h
rt, 1 h
rt, 1 h
rt, 1 h
rt, 1 h
rt, 1 h
2a (44), 3 (8), 4a (30)
2b (30), 4b (9), 5a (14)
2c (25), 4c (15), 5b (6)
2d (28), 4d (15), 5c (9)
2e (59)
fluorobenzene
chlorobenzene
bromobenzene
p-xylene
benzene
6a (92)
fluorobenzene
bromobenzene
toluene
6b (32), 7a (51)
6c (57), 7b (19)
6d (35), 7c (29)
Table 2 Reaction of 1a and 1b with arenes in solvents in the presence of AlCl3
Molar quotient AlCl3
Arene/Reagent (equiv.) Solvent
Reaction Product
Temperature time (t/h) (yield, %)
Entry Reagent Arene
1
2
3
4
1a
1a
1a
1a
naphthalene
naphthalene
naphthalene
biphenyl
1.1
1.1
2.0
1.5
5
10
5
CH NO
rt
17
4
4
2f (47)
2f (78)
2f (78)
2g (8),
3
2
a
CH NO –HFIP (1 : 1) rt
3
2
CH NO –HFIP (1 : 1)
rt
reflux
3
2
5
HFIP
1.5
2
h (57)
5
6
7
8
9
0
1a
1a
1b
1b
1b
1b
fluorene
1.1
1.5
1.1
2.0
2.0
10
5
10
5
5
5
CH NO –HFIP (1 : 1)
rt
reflux
rt
rt
rt
48
0.33
4
2
4.5
9
2i (73)
2j (71)
6e (65)
6e (76)
6f (39)
6g (71)
3
2
dibenzofuran
naphthalene
naphthalene
phenol
HFIP
CH NO –HFIP (1 : 1)
3
2
CH Cl –HFIP (1 : 1)
2
2
CH Cl –HFIP (1 : 1)
2
2
1
N-(N-methylanilino)phthalimide 1.0
CH Cl –HFIP (1 : 1)
rt
2
2
a
HFIP: 1,1,1,3,3,3-Hexafluoropropan-2-ol.
N-methylphenylnitrenium ion seems to be extraordinarily
reactive to nucleophiles. This kind of reaction consistently
occurred not only with naphthalene, but also with other arenes
examined (Table 1, entries 6–9; Table 2, entries 7–10). The exact
reasons for this exclusive and regioselective C-substitution have
not been established.
We have extended these studies to include reactions with
other arenes. A slight molar excess of fluorene and dibenzo-
furan reacted with 1a in the presence of AlCl to afford 2i and 2j
3
in 73% and 71% yield, respectively (Table 2, entry 5 and 6). The
product 2i was identified as (9H-fluoren-2-yl)aniline by com-
parison of the UV absorption [λmax (EtOH) 320 nm] and melt-
13
ing point (138–139 ЊC) with those of the reported values [λmax
EtOH) 316 nm, mp 135–136 ЊC]. Data of the other positional
(
isomers of 2i are listed in ref. 14. The product 2j was determined
1
to be (dibenzofuran-3-yl)aniline by H NMR spectroscopy and
X-ray crystallography. The presence of a doublet resonance (δ
1
7
.93, J = 8.2 Hz) of the proton on C-1 in the H NMR spectrum
indicates that the anilino group should be substituted on C-3
or C-4. Unfortunately, the signals of H-3 and H-4 of 2j and
the N-acetyl compound 8 were not separated. Ultimately, we
subjected 8 to single-crystal X-ray crystallography. The X-ray
diffraction data (Fig. 1) unambiguously showed the anilino
group was substituted on C-3.
Scheme 2
In contrast to these results, when we used 1b as a starting
compound, C-substitution occurred exclusively to give 6e
in 76% yield (Table 2, entry 8). The para position of an
Electrophilic aromatic substitution reactions, such as halo-
genation, acylation and chloromethylation, all take place at C-2
J. Chem. Soc., Perkin Trans. 1, 2001, 3064–3068
3065

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Reaction of 1a in fluorobenzene. Compounds 2b, 4b and 5a
were obtained by reaction of 1a with AlCl in fluorobenzene
3
according to the typical procedure for Table 1. Compound 2b:
17
Ϫ1
colourless crystals; mp 34–35 ЊC (lit., 34 ЊC); νmax(KBr)/cm
400, 1600, 1510, 1320, 1220; δ (270 MHz; CDCl ) 5.56 (1H, br
3
H
3
s, NH), 6.84–7.09 (7H, m, ArH), 7.25 (2H, dd, J 8.5, 7.3, ArH);
ϩ
m/z (EI) 187 (M , 100%), 186 (38). Compound 4b: pale yellow
26
Ϫ1
crystals; mp 36.5–37.5 ЊC (lit., 36 ЊC); νmax(KBr)/cm 3470,
3
6
380, 1520, 1485; δ (270 MHz; CDCl ) 3.78 (2H, br s, NH ),
H 3 2
.76 (2H, d, J 8.8, ArH), 6.97–7.30 (3H, m, ArH), 7.33–7.38
ϩ
(
3H, m, ArH); m/z (EI) 187 (M , 100%), 159 (7). Compound
27
5
a: pale yellow crystals; mp 121–122 ЊC (lit., 120 ЊC);
Ϫ1
νmax(KBr)/cm 3425, 3300, 1635, 1615, 1500; δ (270 MHz;
Fig. 1 ORTEP drawing of the X-ray crystallographic structure of
N-(dibenzofuran-3-yl)-N-phenylacetamide 8
H
CDCl ) 3.72 (2H, br s, NH ), 6.75 (2H, d, J 8.4, ArH), 7.07 (2H,
3
2
t, J 8.7, ArH), 7.35 (2H, d, J 8.4, ArH), 7.47 (2H, dd, J 8.7, 5.0,
ArH); m/z (EI) 187 (M , 100%), 186 (15).
ϩ
of dibenzofuran due to the participation of the lone pair of the
15
ring oxygen. Further substitution by these methods results
15
in the production of the 2,8-disubstituted compounds. It is
noteworthy that, in every case studied, exclusively mono-
anilinated compounds were produced by the electrophilic
phenylamination reaction. The anilino group that presumably
Reaction of 1a in chlorobenzene. Compounds 2c, 4c and 5b
were obtained by reaction of 1a with AlCl in chlorobenzene
3
according to the typical procedure for Table 1. Compound 2c:
18
colourless crystals; mp 67–68 ЊC (lit., 66–68 ЊC); νmax(KBr)/
Ϫ1
is coordinated with AlCl appears to deactivate the aromatic
cm 3400, 1590, 1500, 1320; δ (270 MHz; CDCl ) 5.64 (1H, br
3
H
3
ring sufficiently to prevent further anilination.
s, NH), 6.95 (1H, t, J 7.0, ArH), 6.99 (2H, d, J 9.0, ArH), 7.04
2H, d, J 8.5, ArH), 7.21 (2H, d, J 9.0, ArH), 7.24–7.31 (2H, m,
(
ϩ
ϩ
ArH); m/z (EI) 205 (M ϩ 2, 33%), 203 (M , 100), 167 (41).
ϩ
Compound 4c: a pale yellow oil (Found: M , 203.0521.
Ϫ1
C H ClN requires M, 203.0502); νmax(film)/cm 3460, 3380,
12
10
1
520, 1470; δ (270 MHz; CDCl ) 5.79 (2H, br s, NH ), 6.75
H
3
2
(
2H, d, J 8.8, ArH), 7.16–7.34 (5H, m, ArH), 7.44 (1H, dd,
ϩ
ϩ
J 7.7, 7.1, ArH); m/z (EI) 205 (M ϩ 2, 33%), 203 (M , 100),
1
1
In summary, our studies show that a phenylnitrenium ion
28
67 (21). Compound 5b: pale yellow crystals; mp 132 ЊC (lit.,
generated from phenylhydrazine in the presence of AlCl was
Ϫ1
3
32–133 ЊC); νmax(KBr)/cm 3420, 3320, 1610, 1485; δ (270
H
trapped with solvent arenes to give both aromatic N-substi-
tution and C-substitution products, while an N-methylphenyl-
nitrenium ion generated from N-methyl-N-phenylhydrazine
reacted with arenes to give exclusively aromatic C-substitution
products. Equimolar reactions of a phenylnitrenium ion with a
series of arenes produced anilinated arenes in moderate to good
yields.
MHz; CDCl ) 3.68 (2H, br s, NH ), 6.75 (2H, d, J 8.4, ArH),
3
2
7
.34 (2H, d, J 6.5, ArH), 7.38 (2H, d, J 6.5, ArH), 7.45 (2H,
ϩ
ϩ
d, J 8.8, ArH); m/z (EI) 205 (M ϩ 2, 32%), 203 (M , 100),
1
67 (18).
Reaction of 1a in bromobenzene. Compound 2d, 4d and 5c
were obtained by reaction of 1a with AlCl in bromobenzene
3
according to the typical procedure for Table 1. Compound 2d:
1
9
Ϫ1
Experimental
Melting points were determined on a Yanagimoto micro-
melting point apparatus and are uncorrected. IR spectra were
colourless crystals; mp 86–87 ЊC (lit., 88 ЊC); νmax(KBr)/cm
400, 1585, 1505, 1485; δ (270 MHz; CDCl ) 5.68 (1H, br s,
3
H
3
NH), 6.88–7.02 (1H, m, ArH), 6.94 (2H, d, J 8.8, ArH), 7.05
2H, d, J 8.8, ArH), 7.22–7.32 (2H, m, ArH), 7.34 (2H, d, J 8.8,
ArH); m/z (EI) 249 (M ϩ 2, 96%), 247 (M , 100), 167 (32).
Compound 4d: a pale yellow oil (Found: M , 246.9998.
C H BrN requires M, 246.9997); νmax(film)/cm 3460, 3380,
(
1
recorded on a JASCO IR 810 spectrometer. H NMR spectra
ϩ
ϩ
were measured at 270 MHz on JEOL JNM-EX270 or at 500
MHz on JNM-A500 with TMS as internal reference. J-Values
are in Hz. Mass spectra were measured with a JEOL JMS-700
spectrometer using a direct inlet system. Elemental analyses
were performed in the Microanalytical Laboratory of this
University. Compounds 1a, 1b, 2a, 3, 4a, biphenyl, fluorene and
dibenzofuran were purchased from Tokyo Kasei Kogyo Co.
ϩ
Ϫ1
12
10
1
6
625, 1520, 1470; δ (270 MHz; CDCl ) 3.75 (2H, br s, NH ),
H 3 2
.74 (2H, d, J 8.8, ArH), 7.06–7.19 (1H, m, ArH), 7.23 (2H, d,
J 8.8, ArH), 7.29–7.34 (2H, m, ArH), 7.64 (1H, d, J 7.7, ArH);
m/z (EI) 249 (M ϩ 2, 98%), 247 (M , 100), 167 (47). Com-
pound 5c: pale yellow crystals; mp 142 ЊC (lit., 142–143 ЊC);
νmax(KBr)/cm 3420, 3330, 1610, 1525, 1485; δ (270 MHz;
CDCl ) 3.78 (2H, br s, NH ), 6.75 (2H, d, J 8.4, ArH), 7.36 (2H,
ϩ
ϩ
29
1
6
17
18
19
20
The following compounds are known; 2a, 2b, 2c,8 2d, 2e,
Ϫ1
21
22
23
13
24
25
26
27
28
29
8
H
2
f, 2g, 2h, 2i, 3, 4a, 4b, 5a, 5b, 5c, 6a, 6g .
3
2
d, J 5.1, ArH), 7.41 (2H, d, J 5.1, ArH), 7.51 (2H, d, J 8.8,
ArH); m/z (EI) 249 (M ϩ 2, 99%), 247 (M , 100), 167 (47).
Reaction of phenylhydrazine 1a in benzene in the presence of
ϩ
ϩ
AlCl . Typical procedure for Table 1
3
To a solution of phenylhydrazine 1a (150 mg, 1.39 mmol) in
Reaction of 1a in p-xylene. Compound 2e was obtained by
benzene (10 mL) was added AlCl (925 mg, 6.94 mmol) at room
reaction of 1a with AlCl in p-xylene according to the typical
3
3
20
temperature. After the solution had been stirred for 1 h, the
reaction mixture was quenched with 5% aq. Na CO (40 mL)
procedure for Table 1. Compound 2e: a pale yellow oil;
νmax(film)/cm 3390, 3050, 1600, 1580, 1520, 1500; δ (270
Ϫ1
2
3
H
with cooling. The aqueous layer was extracted with ethyl
acetate (2 × 20 mL) and the combined organic layers were
washed with brine (25 mL), dried (Na SO ), and concentrated.
MHz; DMSO-d ) 2.14 (3H, s, CH ), 2.20 (3H, s, CH ), 6.70–
6
3
3
6.76 (2H, m, ArH), 6.86 (2H, dd, J 7.5, 2.0, ArH), 6.97 (1H, s,
ArH), 7.06 (1H, d, J 7.7, ArH), 7.17 (2H, dt, J 7.3, 2.0, ArH),
2
4
ϩ
The crude product was chromatographed on a column of silica
7.30 (1H, s, NH); m/z (EI) 197 (M , 100%), 196 (38), 182 (20),
gel (benzene–ethyl acetate 30 : 1) to give 2a (71 mg, 44%), 3
181 (17), 180 (20).
(
10 mg, 8%), and 4a (53 mg, 30%) in order of elution. 2a:
1
6
2
4
mp 53–54 ЊC (lit., 54–55 ЊC). 3: mp 44–46 ЊC (lit., 49–50 ЊC).
4
Reaction of N-methyl-N-phenylhydrazine 1b in benzene.
25
a: mp 50–51 ЊC (lit., 50–51 ЊC). Spectral data of 2a, 3, and 4a
Compound 6a was obtained by reaction 1b with AlCl in ben-
zene according to the typical procedure for Table 1. Compound
3
were identical with those of commercially available samples.
3
066
J. Chem. Soc., Perkin Trans. 1, 2001, 3064–3068

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8
ϩ
6
a: a pale yellow oil (Found: M , 183.1054. Calc. for C H N:
NH), 6.92 (1H, t, J 7.0, ArH), 6.99 (2H, d, J 8.0, ArH), 7.21–
13
13
Ϫ1
M, 183.1048); νmax(film)/cm 3410, 1615, 1530, 1490; δ (270
MHz; CDCl ) 3.17 (3H, s, CH ), 3.78 (1H, br s, NH), 6.68 (2H,
7.29 (2H, m, ArH), 7.34–7.59 (5H, m, ArH), 7.83–7.89 (1H, m,
H
ϩ
ArH), 7.99–8.02 (1H, m, ArH); m/z (EI) 219 (M , 100%), 218
3
3
d, J 9.3, ArH), 7.24 (1H, t, J 7.6, ArH), 7.38 (2H, t, J 7.6, ArH),
.45 (2H, d, J 9.3, ArH), 7.54 (2H, d, J 7.6, ArH); m/z (EI) 183
(45), 109 (16).
7
ϩ
(
M , 100%) 182 (47), 152 (12).
Reaction of 1a with biphenyl. Compounds 2g and 2h were
obtained by reaction of 1a with biphenyl (1.5 molar equiv.)
according to the typical procedure for Table 2 except that the
reaction mixture was refluxed in HFIP for 1.5 h. Compound
Reaction of 1b in fluorobenzene. Compounds 6b and 7a were
obtained by reaction of 1b with AlCl in fluorobenzene accord-
3
22
ϩ
2
g: a pale yellow oil (Found: M , 245.1204. Calc. for
18 15
ing to the typical procedure for Table 1. Compound 6b: a pale
Ϫ1
ϩ
C H N: M, 245.1200); νmax(film)/cm 3400, 1590, 1505, 1490;
yellow oil (Found: M , 202.0947. C H FN requires M,
1
3
12
Ϫ1
δ (270 MHz; CDCl ) 6.68 (1H, t J 7.1, ArH), 6.83 (2H, d, J 7.1,
2
01.0954); νmax(film)/cm 3430, 1620, 1535, 1490; δ (270 MHz;
H
3
H
ArH), 7.07–7.13 (3H, m, ArH), 7.22 (1H, br s, NH), 7.26–7.32
4H, m, ArH), 7.38 (2H, d, J 7.3, ArH), 7.52 (2H, dd, J 7.1,
CDCl ) 2.88 (3H, s, CH ), 3.47 (1H, br s, NH), 6.67 (2H, d,
3
3
(
J 8.8, ArH), 7.07–7.27 (3H, m, ArH), 7.34–7.47 (3H, m, ArH);
ϩ
ϩ
ArH); m/z (EI) 245 (M , 100%), 244 (43), 167 (14). Compound
2
m/z (EI) 201 (M , 100%), 200 (57), 170 (12). Compound 7a:
23
h: pale yellow crystals; mp 113.5–114.5 ЊC (Found: C, 88.18;
colourless crystals (Found: C, 77.46; H, 6.11; N, 6.89.
H, 6.09; N, 6.73. Calc. for C H N: C, 88.13; H, 6.16; N,
C H FN requires C, 77.59; H, 6.01; N, 6.96%); mp 100–
18 15
1
3
12
Ϫ1
Ϫ1
5
.71%); νmax(KBr)/cm 3400, 3370, 1600, 1520, 1500, 1485;
1
00.5 ЊC; νmax(KBr)/cm 3450, 1615, 1510; δ (270 MHz;
H
δ (270 MHz; CDCl ) 6.85 (1H, t, J 7.3, ArH), 7.11–7.17 (4H,
CDCl ) 2.88 (3H, s, CH ), 3.32 (1H, br s, NH), 6.68 (2H, d,
H
3
3
3
m, ArH), 7.23–7.31 (3H, m, ArH), 7.42 (2H, t, J 7.3, ArH), 7.56
2H, dd, J 7.5, 2.9, ArH), 7.61 (2H, d, J 7.1, ArH), 8.32 (1H,
J 8.4, ArH), 7.07 (2H, t, J 8.8, ArH), 7.39 (2H, d, J 8.8, ArH),
ϩ
(
7
(
.47 (2H, dd, J 7.3, 5.5, ArH); m/z (EI) 201 (M , 100%), 200
ϩ
br s, NH); m/z (EI) 245 (M , 100%), 244 (17), 168 (9).
49), 170 (11).
Reaction of 1a with fluorene. Compound 2i was obtained by
reaction of 1a with fluorene (1.1 molar equiv.) according to the
typical procedure for Table 2 except that the reaction mixture
Reaction of 1b in bromobenzene. Compounds 6c and 7b was
obtained by reaction of 1b with AlCl in bromobenzene accord-
3
ing to the typical procedure for Table 1. Compound 6c: a pale
ϩ
was stirred for 48 h in the presence of AlCl (10 molar eq.).
3
yellow oil (Found: M , 261.0145. C H BrN requires M,
1
3
12
14
Ϫ1
Compound 2i: colourless crystals; mp 138–139 ЊC (lit., 135–
2
61.0153); νmax(film)/cm 3440, 1620, 1530, 1490, 1470; δ (270
H
1
36 ЊC) (Found: C, 88.39; H, 6.06; N, 5.19. Calc. for C H N:
19 15
14
MHz; CDCl ) 2.88 (3H, s, CH ), 3.81 (1H, br s, NH), 6.67 (2H,
3
3
C, 88.68; H, 5.88; N, 5.44%); λmax(EtOH)/nm 320 [lit.,
d, J 8.6, ArH), 7.06–7.19 (1H, m, ArH), 7.27 (2H, d, J 8.8,
ArH), 7.29–7.33 (2H, m, ArH), 7.64 (1H, d, J 8.1, ArH); m/z
Ϫ1
λmax(EtOH)/nm 316]; νmax(KBr)/cm 3370, 1600, 1515, 1490;
δ (270 MHz; DMSO-d ) 3.85 (2H, s, CH ), 6.84 (1H, t, J 7.3,
ϩ
ϩ
H
6
2
(
7
4
EI) 263 (M ϩ 2, 98%), 261 (M , 100), 152 (26). Compound
ArH), 7.07–7.35 (8H, m, ArH), 7.50 (1H, d, J 7.3, ArH), 7.73
b: pale yellow crystals; mp 131–133 ЊC (Found: C, 59.42; H,
ϩ
(
2H, d, J 8.3, ArH), 8.28 (1H, s, NH); m/z (EI) 257 (M , 100%),
.62; N, 5.31. C H BrN requires C, 59.56; H, 4.61; N, 5.34%);
13
12
Ϫ1
165 (44).
νmax(KBr)/cm 3240, 1615, 1535, 1480; δ (270 MHz; CDCl )
H
3
2
7
.88 (3H, s, CH ), 3.82 (1H, br s, NH), 6.96 (2H, d, J 8.8, ArH),
3
Reaction of 1a with dibenzofuran. Compound 2j was obtained
.37–7.44 (4H, m, ArH), 7.50 (2H, d, J 8.8, ArH); m/z (EI) 263
ϩ
ϩ
by reaction of 1a with dibenzofuran (1.5 molar equiv.) accord-
ing to the typical procedure for Table 2 except that the reaction
mixture was refluxed for 20 min. Compound 2j: colourless
crystals; mp 134–135 ЊC (Found: C, 83.31; H, 5.06; N, 5.15.
C H NO requires C, 83.38; H, 5.05; N, 5.40%); νmax(KBr)/
(
M ϩ 2, 97%), 261 (M , 100), 152 (73).
Reaction of 1b in toluene. Compounds 6d and 7c were
obtained by reaction of 1b with AlCl in toluene according to
the typical procedure for Table 1. Compound 6d: a pale yellow
oil (Found: M , 197.1194. C H N requires M, 197.1204);
νmax(film)/cm 3420, 1620, 1530, 1490; δ (270 MHz; CDCl )
3
18
Ϫ1
13
cm 3420, 1600, 1510; δ (270 MHz; DMSO-d ) 6.91 (1H, t,
ϩ
H
6
14
15
J 7.3, ArH), 7.09 (1H, dd, J 8.4, 2.0, ArH), 7.19 (2H, d, J 8.1,
ArH), 7.27–7.40 (5H, m, ArH), 7.59 (1H, d, J 7.5, ArH), 7.93
Ϫ1
H
3
2
.30 (3H, s, CH ), 2.88 (3H, s, CH ), 3.72 (1H, br s, NH), 6.66
3
3
(
1H, d, J 8.2, ArH), 7.96 (1H, d, J 7.1, ArH), 8.56 (1H, br s,
(
2H, d, J 8.8, ArH), 7.18 (2H, d, J 8.8, ArH), 7.20–7.30 (4H, m,
ϩ
NH); m/z (EI) 259 (M , 100%), 230 (10).
ϩ
ArH); m/z (EI) 197 (M , 100%), 196 (42), 165 (13). Compound
c: pale yellow crystals; mp 69–70.5 ЊC (Found: C, 85.53;
H, 7.74; N, 7.04. C H N requires C, 85.24; H, 7.66; N, 7.10%);
7
Reaction of 1b with naphthalene. Compound 6e was obtained
by reaction of 1b with naphthalene (2.0 molar equiv.) according
to the typical procedure for Table 2 except for the use of
CH Cl –HFIP (1 : 1) as solvent. Compound 6e: a pale yellow
1
4
15
Ϫ1
νmax(KBr)/cm 3410, 1620, 1510; δ (270 MHz; CDCl ) 2.37
H
3
(
3H, s, CH ), 2.87 (3H, s, CH ), 3.59 (1H, br s, NH), 6.67 (2H,
3
3
2
2
d, J 8.6, ArH), 7.20 (2H, d, J 8.1, ArH), 7.40–7.47 (4H, m,
ArH); m/z (EI) 197 (M , 100%), 196 (37), 182 (9), 152 (7).
ϩ
ϩ
oil (Found: M , 233.1211. C H N requires M, 233.1204);
17 15
Ϫ1
νmax(KBr)/cm 3430, 1740, 1620; δ (270 MHz; CDCl ) 2.93
H
3
(
3H, s, CH ), 3.95 (1H, br s, NH), 6.76 (2H, d, J 6.0, ArH), 7.35
3
Reaction of 1a with naphthalene in the presence of AlCl . Typical
procedure for Table 2
3
(2H, d, J 6.0, ArH), 7.37–7.53 (4H, m, ArH) 7.80 (1H, d, J 8.0,
ArH), 7.88 (1H, d, J 8.0, ArH), 8.00 (1H, d, J 8.0, ArH);
m/z (EI) 233 (M , 100%), 232 (25), 202 (18), 189 (10).
ϩ
To a solution of phenylhydrazine 1a (150 mg, 1.39 mmol) and
naphthalene (356 mg, 2.78 mmol) in CH NO –HFIP (1 : 1)
3
2
(
5 mL) was added AlCl (925 mg, 6.94 mmol) at room temper-
Reaction of 1b with phenol. Compound 6f was obtained by
reaction of 1b with phenol according to the typical procedure
for Table 2 except for the use of CH Cl –HFIP (1 : 1) as solvent.
3
ature. After the solution had been stirred for 4 h, the reaction
mixture was quenched with 5% aq. Na CO (40 mL) with cool-
2
3
2
2
ing. The aqueous layer was extracted with ethyl acetate (2 ×
0 mL) and the combined organic layers were washed with
brine (25 mL), dried (Na SO ), and concentrated. The crude
Compound 6f: colourless crystals; mp 171.5–173 ЊC (Found:
2
C, 78.31; H, 6.64; N, 6.99. C H NO requires C, 78.30; H, 6.58;
13
13
Ϫ1
N, 7.03%); νmax(KBr)/cm 3400, 3325, 1615, 1510; δ (270
2
4
H
product was chromatographed on a column of silica gel
tetrahydrofuran–hexane 1 : 20) to give 2f (232 mg, 78%);
MHz; CDCl ) 2.69 (3H, s, CH ), 5.63 (1H, br s, NH), 6.57 (2H,
3
3
(
d, J 8.8, ArH), 6.77 (2H, d, J 8.8, ArH), 7.31 (2H, d, J 7.2,
ArH), 7.34 (2H, d, J 7.2, ArH), 9.29 (1H, s, OH); m/z (EI) 199
21
Ϫ1
colourless crystals; mp 59 ЊC (lit., 59 ЊC); νmax(KBr)/cm
410, 1610, 1595, 1580; δ (270 MHz; CDCl ) 5.86 (1H, br s,
ϩ
3
(M , 100%), 198 (33), 184 (16).
H
3
J. Chem. Soc., Perkin Trans. 1, 2001, 3064–3068
3067

View Article Online
Reaction of 1b with N-(N-methylanilino)phthalimide. Com-
pound 6g was obtained by reaction of 1b with N-(N-methyl-
anilino)phthalimideaccordingtothetypicalprocedureforTable2
except for the use CH Cl –HFIP (1 : 1) as solvent. Compound
3 J. H. Parish and M. C. Whiting, J. Chem. Soc., 1964, 4713.
4
(a) H. Takeuchi, K. Takano and K. Koyama, J. Chem. Soc., Chem.
Commun., 1982, 1254; (b) H. Takeuchi, M. Maeda, M. Mitani and
K. Koyama, J. Chem. Soc., Chem. Commun., 1987, 57.
G. A. Olah, P. Ramaiah, Q. Wang and G. K. S. Prakash, J. Org.
Chem., 1993, 58, 6900.
2
2
5
6
7
8
6
g: colourless crystals; mp 250–251 ЊC (lit., 250–251 ЊC).
T. Ohta, S. Miyake and K. Shudo, Tetrahedron Lett., 1985, 26,
5811.
N-(Dibenzofuran-3-yl)-N-phenylacetamide (8)
H. Takeuchi and K. Koyama, J. Chem. Soc., Perkin Trans. 1, 1988,
To a mixture of sodium hydride (22 mg, 0.925 mmol) in ben-
zene (5 mL) was added a solution of 2j (200 mg, 0.771 mmol)
in DMF (5 mL) at 0 ЊC. The mixture was warmed to room
temperature and stirred for 20 min. Acetyl chloride (0.07 mL,
2
277; H. Takeuchi, S. Hayakawa, T. Tanahashi, A. Kobayashi,
T. Adachi and D. Higuchi, J. Chem. Soc., Perkin Trans. 1, 1991,
47; R. A. Abramovitch and Q. Shi, Heterocycles, 1994, 37, 1463;
R. J. Moran, C. Cramer and D. E. Falvey, J. Org. Chem., 1997, 62,
742.
8
2
0
2
.925 mmol) was then added and the solution was stirred for
0 h. The reaction mixture was quenched with 7% aq. H SO
8
A. Ohwada, H. Li, T. Sakamoto and Y. Kikugawa, Heterocycles,
1997, 46, 225.
9 A. E. Arbusow and W. M. Tichwinsky, Ber. Dtsch. Chem. Ges., 1910,
43, 2295; K. Clusius and M. Hoch, Helv. Chim. Acta, 1950, 33,
2
0 H. Imaizumi, Y. Hashida and K. Matsui, Bull. Chem. Soc. Jpn.,
1
1 H. Takeuchi and K. Takano, J. Chem. Soc., Perkin Trans. 1, 1986,
611.
2
4
(
10 mL) and the aqueous layer was extracted with benzene (10
mL). The organic layer was washed with brine (15 mL), dried
Na SO ), and concentrated. The crude product was chromato-
122.
(
2
4
1
1
graphed on a column of silica gel (hexane–ethyl acetate 1 : 2) to
give compound 8 (154 mg, 66%) as yellow crystals; mp 120 ЊC
978, 51, 1507.
(
7
1
(
Found: C, 79.54; H, 4.94; N, 4.94. C H NO requires C,
20 15 2
Ϫ1
9.72; H, 5.02; N, 4.56%); νmax(KBr)/cm 3060, 1675, 1635,
595, 1580; δ (270 MHz; CDCl ) 2.12 (3H, s, CH ), 7.25–7.54
12 J. Ichikawa, S. Miyazaki, M. Fujiwara and T. Minami, J. Org.
Chem., 1995, 60, 2320.
H
3
3
ϩ
10H, m, ArH), 7.92 (2H, d, J 6.8, ArH); m/z (EI) 301 (M ,
0%), 259 (100).
1
3 Y. Yost, H. R. Gutmann and C. C. Muscoplat, J. Chem. Soc. C,
971, 2119.
4 Y. Yost and H. R. Gutmann, J. Org. Chem., 1973, 38, 165
1
4
1
(
(
9H-fluoren-1-yl)aniline: λmax (EtOH) 266 nm, mp 130–131 ЊC;
9H-fluoren-3-yl)aniline: λmax (EtOH) 264, 298 nm, mp 145–147 ЊC.
X-Ray crystallography of 8†
1
1
5 M. V. Sargent and F. M. Dean, in Comprehensive Heterocyclic
Chemistry, ed. A. R. Katritzky, Pergamon Press, Oxford, 1984,
vol. 4, p. 643.
6 G. Brown, M. S. Kharash and W. R. Sprowls, J. Org. Chem., 1939,
4, 442.
Data collection and refinement. Data were collected on a
Rigaku RAXIS imaging plate area detector with graphite-
monochromated Mo-Kα radiation (λ = 0.710 69 Å). The struc-
30
tures was solved by the direct method (SIR92) and expanded
using Fourier techniques. All non-hydrogen atoms were refined
anisotropically. All calculations were performed using the
17 N. L. Smith, J. Org. Chem., 1951, 16, 415.
8 H. Burton and C. S. Gibson, J. Chem. Soc., 1926, 2241.
19 O. Süs, Justus Liebigs Ann. Chem., 1947, 557, 237.
1
31,32
CrystalStructure
software package.
2
2
2
0 J. P. Wolfe and S. L. Buchwald, J. Org. Chem., 1996, 61, 1133.
1 H. H. Hodgson and E. Marsden, J. Chem. Soc., 1938, 1181.
2 Y. Yost, J. Heterocycl. Chem., 1972, 9, 151.
Crystal data. Crystal dimensions 0.50 × 0.50 × 0.45 mm,
C H NO , M = 301.34, monoclinic, P2 /c (No. 14), a =
20
15
2
1
23 J. Cymerman-Craig, W. P. Rogers and G. P. Warwick, Aust. J. Chem.,
1955, 8, 252.
24 H. A. Scarborough and W. A. Waters, J. Chem. Soc., 1927, 89.
1
2.9873(3), b = 6.7803(2), c = 17.2761(4) Å, β = 96.1490(5)Њ,
3
Ϫ3
Ϫ1
V = 1512.54(6) Å , Z = 4, D = 1.323 g cm , µ = 0.86 cm ,
c
2
5 F. W. Bergstrom, R. E. Wright, C. Chandler and W. A. Gilkey,
J. Org. Chem., 1936, 1, 170.
6 T. V. Hove, Bull. Soc. Chim. Belg., 1923, 32, 52 (Chem. Abstr., 1923,
17, 3026).
T = 296(1) K, 3761 reflections measured, refinement based on
2
559 reflections. F(000) = 632.00, GOF on F = 1.08, No. of
2
parameters = 224, R = 0.042 [I > 2.00σ(I )], R = 0.071, largest
w
Ϫ3
positive and negative difference peaks ϩ0.27 and Ϫ0.22 e Å .
27 R. Belcher, A. J. Nutten and W. I. Stephen, J. Chem. Soc., 1953,
334.
1
2
2
3
8 M. J. S. Dewar and A. N. James, J. Chem. Soc., 1958, 4265.
9 R. J. W. L. Fèvre and E. E. Turner, J. Chem. Soc., 1926, 2041.
0 A. Altomare, M. Cascarano, C. Giacovazzo and A. Guagliardi,
J. Appl. Crystallogr., 1994, 26, 343.
1 CrystalStructure, Single Crystal Structure Analysis Software,
version 2.0, Molecular Structure Corporation, 9009 New Trails
Drive, The Woodlands, TX, USA, 77381–5209.
†
CCDC reference number 163573. See http://www.rsc.org/suppdata/p1/
b1/b103802h/ for crystallographic files in .cif or other format.
3
References
1
2
M. Novak and J. Lin, J. Org. Chem., 1999, 64, 6032.
R. A. Abramovitch and R. Jeyaraman, in Azides and Nitrenes:
Reactivity and Utility, ed. E. F. V. Scriven, Academic Press, New
York, 1984, p. 297.
32 D. J. Watkin, C. K. Prout, J. R. Carruthers and P. W. Betteridge,
CRYSTALS Issue 10, Chemical Crystallography Laboratory,
Oxford, UK.
3
068
J. Chem. Soc., Perkin Trans. 1, 2001, 3064–3068