Alkenylation of anilines with dicyclopentadiene, cyclopentadiene, and piperylene

Article abstract of DOI:10.1023/A:1012790605083

Alkenylation of anilines with dicyclopentadiene, cyclopentadiene, and piperylene in the presence of mineral acids and Lewis acids was studied.

Full text of DOI:10.1023/A:1012790605083

Russian Journal of Applied Chemistry, Vol. 74, No. 2, 2001, pp. 280 285. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 2, 2001,
pp. 274 280.
Original Russian Text Copyright
2001 by Gataullin, Kazhanova, Sagitdinov, Galyautdinov, Fatykhov, Spirikhin, Abdrakhmanov.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
Alkenylation of Anilines with Dicyclopentadiene,
Cyclopentadiene, and Piperylene
R. R. Gataullin, T. V. Kazhanova, I. A. Sagitdinov, A. A. Galyautdinov,
A. A. Fatykhov, L. V. Spirikhin, and I. B. Abdrakhmanov
Institute of Organic Chemistry, Ufa Scientific Center, Russian Academy of Sciences, Ufa, Bashkortostan, Russia
Bashkir State Agricultural University, Ufa, Bashkortostan, Russia
Salavatnefteorgsintez Joint-Stock Company, Salavat, Bashkortostan, Russia
Received June 16, 2000
Abstract Alkenylation of anilines with dicyclopentadiene, cyclopentadiene, and piperylene in the presence
of mineral acids and Lewis acids was studied.
The discovery of the Claisen rearrangement of ar-
omatic amines [1] provided access to 2-alkenyl-substi-
tuted arylamines, including cyclopentenyl- and pen-
tenylanilines [2], which can be prepared from dicyclo-
pentadiene (DCPD) or piperylene. A number of valu-
able compounds have been prepared from these amines,
such as alkaloids [3], steel corrosion inhibitors, fungi-
cides, plant growth stimulants, antiphytophthora agents,
and local anesthetics [4 6]. The presence in allylani-
line molecules of several reaction centers allows their
transformations involving nitrogen atom, alkenyl frag-
ment, or both centers simultaneously. The possibility
of preparing new biologically active derivatives from
2-alkenylanilines by common reactions of amines or
by certain specific reactions makes these compounds
valuable synthons. To look for an alternative to the
Claisen rearrangement of aromatic amines as a route
to o-alkenylanilines, we studied alkenylation of ani-
lines with DCPD, cyclopentadiene (CPD), and pi-
perylene.
also detected (<3%). When freshly distilled CPD is
taken in reaction with aniline hydrochloride, the yield
of a mixture of exo isomers V and VI decreases some-
what.
NH2
NH2
R
R
Cat., T C
+
I, II
HN
III, IV
NH2
R
+
+
+
N
H
R
V, VI
VII, VIII
IX, X
10
.
.
H
H
5
.
.
8
.
.
.
7
.
.
.
9
6
1
.
.
.
.
.
.
H
H
4
2
3
Reactions of DCPD with amines I and II in
the presence of HCl at 130 220 C gave as main prod-
ucts the previously described [2] o-cyclopentenylani-
lines III and IV (yield of up to 45%) and also N-phe-
nyl-(8S)- (V) and N-phenyl-(8R)-tricyclo[5.2.1.02,6]dec-
3-en-8-amine (VI). Elevated temperatures (200 C) and
longer reaction time favor cyclization of o-cyclopen-
tenylanilines III and IV into hexahydrocyclopent[b]-
indoles VI and VIII [7] and formation of p-cyclopen-
tenylanilines IX and X [8] (Table 1). In the case of
aniline (I), o,o-dicyclopentenylaniline (XI) [9] was
NH2
.
.
.
.
.
.
.
. .
. .
.
.
.
.
.
H
H
+
+
+
(1)
NH2
H2N
XI
XII
XIII
Here Cat. = HCl, AlCl3, FeCl3; R = H (I, III, V
VII, IX, XI); Me (II, IV, VIII, X).
With AlCl3 used instead of HCl, the composition
of the reaction products changes. The ratio of amines
I, IV and IX, X is 1 : 1. The expected products V and
1070-4272/01/7402-0280 $25.00 2001 MAIK Nauka/Interperiodica

ALKENYLATION OF ANILINES WITH DICYCLOPENTADIENE
281
Table 1. Ratio of products of aniline (I) alkenylation with DCPD under various conditions (molar ratio aniline : DCPD
4 : 1)
Product content, %
Catalyst, mol
HCl, 0.4
, h
T,
C
Total yield, %
III
VII
IX
V, VI
XII, XIII
0.5
2
0.5
5
200
50
45
42
29
20
15
15
14
70
60
60
57
150
200
200
3
14
2
AlCl3:
0.37
1.05
0.15
FeCl3 6H2O,
0.15
0.5
0.5
0.5
0.5
200
200
200
200
10
2
2
10
15
9
16
14
28
43
17
13
65
52
64
68
14
20
15
21
Table 2. Substituted anilines in reaction with piperylene in the presence of KU-2 resin (reaction time 5 h, 180 C, molar
ratio amine : piperylene 1 : 3)
R1 R2
N
R7
R6
R3
R4
R5
Substituent
R4
Yield of products,*
%
Total
yield,
%
Initial
amine
R1
R2
R3
R5
R6
R7
2-AA
4-AA
2,4-diAA
II
XIV
XV
XVI
XVII
XVIII
XIX
XX
H
H
H
H
H
H
H
H
Bu
H
H
H
H
H
H
H
H
Bu
Me
H
H
Me
Me
Me
OMe
Cl
H
Me
H
H
H
H
H
H
H
H
H
Me
Me
H
H
OMe
H
H
H
H
H
H
Me
H
H
H
H
H
H
Et
H
H
H
H
13
21
38
58
28
25
24
18
26
65
64
64
58
61
52
38
63
19
61
52
38
22
19
26
15
XXI
H
H
H
*
(AA) Alkenylated aniline.
VI are formed, as well as the products of alkenylation
of the aromatic ring, 2-[(3S)- (XII) and 2-[(3R)-tri-
cyclo-[5.2.1.02,6]dec-8-en-3-yl]amines (XIII). With
increasing amount of AlCl3, the relative content of
III and IX decreases. At a 1 : 1 ratio of DCPD and
AlCl3, only amines XII and XIII are formed. With
the FeCl3 6H2O catalyst taken in the same amount as
AlCl3, the relative content of III and IX is somewhat
higher than that of V, VI, XII, and XIII. In the case
of o-toluidine (II) and AlCl3 catalyst, the composition
of products, according to GLC, is the same as with
that in the case of aniline (I).
The structure of V XIII was confirmed by spec-
troscopic methods [10] and elemental analysis. The
IR spectra [11] of V and VI contain a characteristic
1
band of the NH group at 3430 cm , and the spectra
of XII and XIII, the bands of the NH2 group at 3390
1
1
and 3470 cm . The aromatic protons in the H NMR
spectrum of IX appear as two doublets (2H each)
at 6.12 and 7.00 ppm. The methine 1 -H signal is
a multiplet (1H) at 3.85 ppm. The broadened singlet
of the NH group is observed at 3.50 ppm. Four pro-
tons of two CH2 groups give rise to multiplets at
1.60 (1H) and 2.40 ppm (3H).
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 74 No. 2 2001

282
GATAULLIN et al.
In N-substituted anilines, the C2 and C6 atoms, as
tic doublets at 52.95 (56.42) ppm in the 13C NMR
spectrum and by single-proton doublets of doublets of
exo protons at 3.34 (3.33) ppm (3 : 1 ratio) in the 1H
NMR spectrum. The 13C NMR spectrum of V and VI
contains only one signal of the C3 cyclopentene car-
bon atom (in V; in VI it is C5), whereas the spec-
trum of the mixture of diastereomers XII and XIII
contains in the range 26.6 33.4 ppm six signals: 29.6,
32.6, and 36.6 ppm for anti diastereomer XIII and
32.2, 33.4, and 33.5 ppm for syn diastereomer XII.
The o-substitution of the aromatic ring is confirmed
by calculations using additive parameters.
well as the C3 and C5 atoms, are mutually equivalent.
Therefore, the corresponding region of the 13C NMR
spectrum contains only four aromatic carbon signals
and two signals of the olefin carbon atoms of the tri-
cyclodecene moiety.
The 13C NMR spectrum of o-substituted anilines
XII and XIII contains in the region of aromatic car-
bon signals two sets of signals (eight signals each).
Twelve of these 16 signals were assigned to the car-
bon atoms of the phenyl ring using the pulse train of
a J-modulated spin echo.
In the case of p-substitution, the 13C NMR spec-
trum would be simpler owing to the symmetrical struc-
ture of the aromatic moiety. Exo addition of the N-phe-
nyl substituent to DCPD in V and VI is confirmed by
the upfield shift (to 39.6 and 39.4 ppm) of the tri-
plet of the bridging C10 atom. The formation of iso-
meric products V and VI is confirmed by characteris-
The results of alkenylation of anilines I, II, and
XIV XXI with piperylene in the presence of KU-2
are listed in Table 2. The reaction is selective and, in
the case of 2,4-xylidine (XVI) and 2-methyl-6-ethyl-
aniline (XVII), yields a single product. This is due to
the availability in these amines of only one position
capable of alkenylation:
R1
R2
R1
R2
R1
R2
NH2
N
N
N
R7
R6
R3
R4
R3
R4
R7
R6
R3
R4
Cat., T C
+
+
R6
R5
R5
Me
XL
I, II, XIV XXI
XXII XXVIII
R1 R2
XXIX XXXIV
NH2
N
R3
(2)
+
+
,
R4
R6
XXV
XXXV XXXIX
where R1 = R2 = R3 = R4 = R5 = R6 = R7 = H (I, XXII, XXIX, XXXV); R1 = R2 = R4 = R5 = R6 = R7 = H, R3 = Me
(II, XXII, XXX, XXXV); R1 = R2 = R3 = R5 = R6 = R7 = H, R4 = Me (XIV, XXIV, XXXI; R1 = R2 = R3 = R4 = R6 =
R7 = H, R5 = Me (XV, XXV); R1 = R2 = R4 = R6 = R7 = H, R3 = R5 = Me (XVI, XXVI); R1 = R2 = R4 = R5 = R6 = H,
R3 = Me, R7 = Et (XVII, XXXII); R1 = R2 = R4 = R5 = R7 = H, R3 = R6 = Me (XVIII, XXXIII); R1 = R2 = R4 = R6 =
R7 = H, R3 = R5 = OMe (XIX, XXVII); R1 = R2 = R4 = R5 = R6 = R7 = H, R3 = Cl (XX, XXVIII, XXXIV, XXXVII);
R1 = R2 = Bu, R4 = R6 = R7 = R3 = R5 = H (XXI, XXXIX).
In the case of 2,5-xylidine (XVIII), and also
with N,N-dibutylaniline (XXI), the formation of
a single product is probably due to the steric and elec-
tronic effects of substituents. Alkylation of aniline (I)
with piperylene in the presence of supported H3PO4
gives a large set of products in low total yield (Ta-
ble 3). With AlCl3 used as catalyst for alkenylation
of piperylene, the best result was achieved in synthe-
sis of 2,4-tri(1-methylbut-2-en-1-yl)aniline. In other
cases, it is impossible to selectively obtain a single
product although the total yield is sometimes high,
(Table 4).
The physicochemical characteristics of compounds
alkenylated with piperylene were reported in [12 14].
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 74 No. 2 2001

ALKENYLATION OF ANILINES WITH DICYCLOPENTADIENE
283
Table 3. Alkenylation of aniline (I) with piperylene in the presence of supported H3PO4 (reaction time 5 h, 150 C)
Yield of products, %
4-AA
Total
yield,
%
Aniline : piperylene
molar ratio
Catalyst
2-AA
2,4-diAA
10% H3PO4 on silica gel
10% H3PO4 on kieselguhr
18% H3PO4 on silica gel
SF-300, polyphosphoric acid
10% H3PO4 on silica gel*
1 : 1
1 : 2
1 : 3
1 : 1
1 : 2
1 : 3
1 : 1
1 : 2
1 : 3
1 : 1
1 : 2
1 : 3
1 : 1
1 : 2
1 : 3
6.5
12
9
4.5
6
8
10.5
12
20
9
21
29
4
16
14
5
8
8
11
18
17
22
26
44
21
42
69
8.5
35
50
12
22
29
11.5
14
22
12
18
34
4.5
19
30
7
Traces
2
3
6
6
9
14
5
7
*
= 5 h, T = 200 C.
Table 4. Alkenylation of aniline with piperylene in the presence of AlCl3
Yield, %
Total yield,
%
Aniline : piperylene
molar ratio
T,
C
, h
Solvent
Toluene
2-AA
4-AA
2,4-diAA 2,4,6-triAA
80
80
80
5
4
3
5
5
5
5
5
5
5
5
5
5
5
5
5
5
1 : 1
1 : 1
1 : 1
1 : 1
1 : 3
1 : 1
1 : 3
1 : 1
1 : 1
1 : 3
2 : 1
1 : 5
1 : 1
1 : 1
1 : 1
1 : 3
1 : 1
3
2
1
6
2
2
4
5
24
9
24
15
10
20
22
13
16
10
27
7
4
2
1
5
17
5
5
5
14
36
4
1
6
8
16
44
21
34
21
13
32
43
19
28
24
67
86
32
99
29
55
84
93
56
100
100
130
130
100
130
130
130
130
150
100
130
130
150
2
3
4
2
Benzene
Hexane
34
9
19
98
3
2
2
5
2
12
21
19
15
18
33
45
25
18
2
EXPERIMENTAL
1200 3-mm column, stationary phase SE-30, 5% on
Chromaton N-AW DMCS, working temperature 50
300 C). Column chromatography was performed on
silica gel LS 40/100 m and Silpearl (eluent hex-
ane). Qualitative TLC analysis was made with Silufol
UV 254 and UV 254/366 plates; the chromatograms
were developed under UV ( = 254 nm) or with
iodine vapor.
The IR spectra were taken on a UR-20 spectrom-
eter, and the H and 13C NMR spectra, on a Bruker
1
AM 300 spectrometer (working frequencies 300 and
75 MHz, respectively). Internal reference TMS, sol-
vent CDCl3. Elemental analysis was performed with
an M-185B C H N analyzer, and the GLC analysis
(including purity check), on a Chrom-5 chromato-
graph (carrier gas helium, flame-ionization detector,
The alkenylation of anilines with DCPD, CPD, and
piperylene was performed in a sealed heat-resistant
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 74 No. 2 2001

284
GATAULLIN et al.
13C NMR spectrum of N-phenyl-(8S)-tricyclo-
ampule or a 17-ml metallic autoclave, charged with
the reactants and catalyst. The component ratios, re-
action times and temperatures, and product yields are
given in Tables 1 4. After the reaction was complete,
the ampule or autoclave was cooled and opened, and
the reaction mixture was transferred with chloroform
into a separatory funnel. The mixture was treated with
5% KOH (2 100 ml), extracted with chloroform
(2 50 ml), and dried over crystalline KOH. Then
the mixture was filtered, the solvent was evaporated,
and the residue was fractionated in a vacuum. With
HCl catalyst, the reaction performed at 140 180 C
gave after vacuum distillation monoalkenylated amine
III or IV. Using the same reaction at 200 C with an-
iline I or II, we isolated, after vacuum distillation,
amine III or IV with an admixture of indoline VII or
VIII and p-substituted product IX or X. Indolines and
p-substituted products were identified by GLC upon
addition of authentic samples [3, 8]. The reaction
with AlCl3 catalyst gave, after vacuum distillation,
a mixture of III + IX or IV + X, chromatographed on
silica gel (eluent benzene). The products were iden-
[5.2.1.02,6]dec-4-en-8-amine (V),
,
ppm: 29.2
C
(C3), 39.4 (C10), 40.6 (C9), 43.2 (C2), 48.1 (C8), 55.1
(C7), 55.9 (C1), 56.42 (C6), 113.00 (C2 , 6 ), 129.30
(C3 , 5 ), 116.80 (C4 ), 131.70 (C5), 132.30 (C4),
147.70 (C1 ).
13C NMR spectrum of N-phenyl-(8R)-tricyclo-
[5.2.1.02,6]dec-4-en-8-amine (VI), C, ppm: 29.2 (C5),
36.6 (C10), 40.5 (C9), 42.3 (C6), 45.5 (C8), 52.9
(C2), 55.8 (C7), 55.9 (C1), 113.2 (C2 , 6 ), 116.90
(C4 ), 129.30 (C3 , 5 ), 131.60 (C3), 132 (C4), 147.60
(C1 ).
2-Methyl-4-(cyclopent-2-enyl)aniline (X). Rf 0.42
1
(hexane MeOH, 99 : 1). IR spectrum, , cm ): 1295,
3390, 3460 (NH2). 1H NMR spectrum, , ppm (J, Hz):
1.50 2.50 m (4H, 2CH2), 2.32 s (3H, CH3), 3.62 br.s
(2H, NH2), 3.95 (1H, CH), 5.90 6.05 m (2H,
CH=CH), 6.74 d (1H, J 7.69, 6-H), 7.04 d (1H, 5-H),
7.10 s (1H, 3-H). 13C NMR spectrum, , ppm: 50.56
(C1 ), 17.40 (CH3), 131.20 (C2 ), 135.02 (C3 ), 32.48
(C4 ), 34.01 (C5 ), 142.85 (C1), 132.36 (C2), 129.21
(C3), 136.62 (C4), 125.57 (C5), 115.06 (C6).
tified by comparison of their H and 13C NMR spec-
1
tra with those of authentic samples [2, 8, 9]. The frac-
tion containing anilines V and VI, prepared by al-
kenylation of I in the presence of HCl, was analyzed
as a mixture. The fraction containing N- (V, VI) and
C-substituted products (X, XI), obtained by the re-
action with AlCl3 catalyst, was separated by chroma-
tography on silica gel (eluent hexane). The V + VI
and X + XI pairs were obtained as several fractions
with varied component ratios. The physicochemical
characteristics of 2-(cyclopent-2-enyl)anilines II and
IV [2] indolines VII and VIII [7], and 4-(cyclopent-
2-enyl)anilines IX and X [8, 9] were consistent with
the relevant published data. Alkenylated anilines
XXII XL were isolated by column chromatography
(alumina, eluent hexane), and their physicochemical
characteristics were compared with those of authentic
samples [12 14].
Found, %: C 83.09, H 8.51, N 7.77.
C12H15N.
Calculated, %: C 83.24, H 8.67, N 8.09.
2,6-Di(cyclopent-2-enyl)aniline (XI). Yield 3%,
bp 168 170 C (2 mm Hg). The physicochemical char-
acteristics agree with published data [2].
Mixture of anilines XII and XIII. IR spectrum, ,
1
1
cm : 3390, 3470 (NH2). H NMR spectrum, , ppm
(J, Hz): 1.20 2.80 m (10H, 3CH2, 4CH); 3.10, 3.23
(unresolved multiplets, Ar CH); 3.60 br.s (2H, NH2);
5.60 5.85 m (2H, CH=CH); 6.70 d (1H, J 7.80, 6 -H);
6.76 t (1H, 5 -H, J 7.80); 7.03 t (1H, 4 -H); 7.18 d
(1H, 3 -H, J 7.70).
Mixture of anilines V and VI. IR spectrum,
,
1
1
cm : 3430 (NH). H NMR spectrum, , ppm (J, Hz):
1.12 2.75 m (10H, 3CH2, 4CH), 3.33 d.d (1H, J1
3.57, J2 7.60, NCH), 3.34 d.d (1H, J1 3.53, J2 7.69,
NCH), 3.62 br.s (1H, NH), 5.49 5.80 m (2H,
CH=CH), 6.66 d (2H, 2-H and 6-H, J 8.25), 6.70 1
(1H, 4-H), 7.20 t (2H, 3-H and 5-H).
Found, %: C 6.12, H 6.79, N 5.00.
C16H19N.
Calculated, %: C 6.27, H 7.45, N 5.49.
13C NMR spectrum of 2-[(3S)-tricyclo-[5.2.1.02,6]-
dec-8-en-3-yl]aniline (XII), C, ppm: 29.6 (C5), 32.6
(C4), 36.6 (C3), 39.1 (C10), 40.3 (C7), 42.1 (C1), 44.2
(C2), 53.6 (C6), 115.4 (C6 ), 118.3 (C4 ), 125.6 (C5 ),
Found, %: C 6.00, H 6.87, N 5.23.
C16H19N.
Calculated, %: C 6.27, H 7.45, N 5.49.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 74 No. 2 2001

ALKENYLATION OF ANILINES WITH DICYCLOPENTADIENE
126.2 (C3 ), 130.7 (C9), 131.8 (C2 ), 132.1 (C8), 144.1
285
4. USSR Inventor’s Certificate, no. 1489133.
(C1 ).
5. Gataullin, R.R., Kazhanova, T.V., Davydova, V.A.,
13C NMR spectrum of 2-[(3R)-tricyclo-[5.2.1.02,6]-
et al., Khim.-Farm. Zh., 1999, no. 5, pp. 29 32.
dec-8-en-3-yl]aniline (XIII), C, ppm: 32.2 (C5), 33.4
(C3), 33.5 (C4), 39.3 (C10), 41.4 (C7), 42.6 (C1), 43.2
(C2), 52.5 (C6), 115.5 (C6 ), 118.1 (C4 ), 125.3 (C5 ),
126.2 (C3 ), 131.3 (C2 ), 132.1 (C8), 132.8 (C9), 144.2
(C1 ).
6. Gataullin, R.R., Kazhanova, T.V., Davydova, V.A.,
et al., Khim.-Farm. Zh., 1999, no. 4, pp. 17 19.
7. Gataullin, R.R., Kazhanova, T.V., Kudashev, A.R.,
et al., Khim.-Farm. Zh., 2000, no. 2, pp. 18 21.
8. Gataullin, R.R., Kazhanova, T.V., Il’yasova, L.T.,
et al., Izv. Ross. Akad. Nauk, Ser. Khim., 1999, no. 5,
pp. 975 978.
CONCLUSION
9. Gataullin, R.R., Kazhanova, T.V., Fatykhov, A.A.,
et al., Izv. Ross. Akad. Nauk, Ser. Khim., 2000, no. 1,
pp. 171 173.
Alkenylation of anilines with dicyclopentadiene or
cyclopentadiene in the presence of HCl yields o-cy-
clopentenylanilines as the main products. At higher
temperatures (200 C) and longer reaction times, per-
hydrocyclopent[b]indolines are formed. With AlCl3
catalyst, both o- and p-cyclopentenyl derivatives are
obtained. Also, significant amounts of dicyclopenta-
diene substitution products are formed in both cases.
Alkenylation of anilines with piperylene gives 2-, 4-,
2,4-di-, and 2,4,6-trialkenylated products. If the 4- or
2,4-positions of the aromatic ring are substituted, the
alkenyl group is introduced at the free o- or p-posi-
tion, respectively.
10. Myshko, V., Kozlikovskii, Ya.B., and Koshchii, V.A.,
Zh. Org. Khim., 1992, vol. 28, pp. 950 954.
11. Ionin, B.I., Ershov, B.A., and Kol’tsov, A.I., YaMR-
Spektroskopiya v organicheskoi khimii (NMR Spec-
troscopy in Organic Chemistry), Leningrad: Khimiya,
1983.
12. Kazitsyna, L.A. and Kupletskaya, N.B., Primenenie
UF-, IK-, YaMR- i mass-spektroskopii v organicheskoi
khimii (Use of UV, IR, NMR, and Mass Spectroscopy
in Organic Chemistry), Moscow: Mosk. Gos. Univ.,
1979, p. 77.
13. Abdrakhmanov, I.B., Sharafutdinov, V.M., Nigmatul-
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RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 74 No. 2 2001