Cyclization of ortho-(alk-2-enyl) anilines under the action of iodine

Article abstract of DOI:10.1023/A:1011309223588

The reaction of ortho-(cyclohex-2-enyl)aniline with I₂ in nonpolar and polar solvents affords predominantly 1-iodohexahydrocarbazole and azatricyclotridecatriene, respectively. Under analogous conditions, 4-methyl-2-(1-methylbut-2-en-l-yl)anili

Full text of DOI:10.1023/A:1011309223588

4
56
Russian Chemical Bulletin, International Edition, Vol. 50, No. 3, pp. 456—459, March, 2001
Cyclization of ortho-(alk-2-enyl)anilines under the action of iodine
R. R. Gataullin,a« F. F. Minnigulov, T. V. Khakimova, T. V. Kazhanova,
b
a
b
a
a
a
A. A. Fatykhov, L. V. Spirikhin, and I. B. Abdrakhmanov
aInstitute of Organic Chemistry, Ufa Research Center of the Russian Academy of Sciences,
1 prosp. Oktyabrya, 450054 Ufa, Russian Federation.
7
Fax: +7 (347 2) 35 6066. E-mail: chemorg@anrb.ru
bBashkir State Agricultural University,
4 ul. 50-letiya Oktyabrya, 450003 Ufa, Russian Federation.
3
The reaction of ortho-(cyclohex-2-enyl)aniline with I2 in nonpolar and polar solvents
affords predominantly 1-iodohexahydrocarbazole and azatricyclotridecatriene, respectively.
Under analogous conditions, 4-methyl-2-(1-methylbut-2-en-1-yl)aniline undergoes cycliza-
tion to form exclusively products with quinoline structures regardless of the solvent used.
Key words: ortho-(alk-2-enyl)anilines, iodocyclization, 1-iodo-1,2,3,4,4a,9a-hexahydro-
carbazole, 13-iodo-2-azatricyclo[7.3.1.02,7]trideca-3,5,7-triene, 3-iodo-1,2,3,4-tetrahydro-
quinolines.
Nitrogen-containing heterocyclic compounds are of-
the analogous reactions of 2-(cyclohex-2-enyl)- and
2-(1-methylbut-2-en-1-yl)anilines prepared from 3-bro-
ten synthesized by cyclization of alkenylamides or
alkenylsulfamides under the action of halogens, in par-
ticular, of iodine.1 Examples of cyclization of amino-
alkenes under these conditions are few in number.2—4
Generally, it is assumed that an onium complex of
alkene with halogen is initially formed in these reactions.
The direction of subsequent transformations of this com-
plex into a heterocycle depends on the reaction condi-
tions, the nature of the solvent, and the structure of the
7
8
mocyclohexene and 3-chloropentene, respectively.
Thus, the reaction of ortho-(cyclohex-2-enyl)aniline
(1) with I2 in the presence of NaHCO3 affords hetero-
cycles 2—4 (Scheme 1) whose ratio depends on the
properties of the solvent (Table 1). In particular, 8-
azatricyclotridecatriene 3 and hexahydrocarbazole 2 were
obtained as the major products in MeCN and CCl4,
respectively. In the reactions performed in MeCN, the
time it took for amine 1 to be converted into reaction
products 2—4 was substantially larger. In addition, the
5
6
alkenyl radical. Recently, we have reported cyclization
of 2-(cyclopent-2-enyl)anilines under the action of I2
giving rise exclusively to 3-iodine-substituted indolines.
As part of our continuing studies, we examined
latter reactions required one more equivalent of I , the
2
yield of diiodo derivative 4 reaching 9%.
Scheme 1
+
I
H
I
1
3
H
1
´
3´
2
´
R
He
1
8
I2
4
2
12
H
9
10
NaHCO3
NH2
NH2
N
H
He
1
A
3
: R = H; 4: R = I
4
3
He
Ha
Ha
He
I
Ha
4
a
He
9
9
a
Ha
N
He
2
N
H
H
1
He
I
Ha
2B
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 437—440, March, 2001.
066-5285/01/5003-456 $25.00 © 2001 Plenum Publishing Corporation
1

Cyclization of ortho-(alk-2-enyl)anilines
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 3, March, 2001
457
Table 1. Dependence of the isomer ratio on the solvent in the
reaction of amine 1 with I2
with the equatorial arrangement of the iodine atom. The
vicinal spin-spin coupling constant between the H(9a)
and H(4a) protons (7.2 Hz) confirms the cis arrange-
Solvent
Reaction
time
Ratio between
the reaction
products, 3 : 2
ment of these protons and, consequently, cis-fusion of
the rings.10—12
/
h
The 13C NMR spectra measured in the pulsed
J-modulated spin-echo mode have doublet signals for
the methine carbon atoms at δ 69.3, 42.6, and 39.0
(C(9a), C(4a), and C(1), respectively) along with the
signals for the carbon atoms of the CH groups of the
benzene fragment. The triplet signal for the C(2) atom is
MeCN
CCl4
cyclo-C H
72
48
72
3 : 1
1 : 3
1 : 6
6 : 1
6
12
HCOOH
130
shifted downfield by 36.3 ppm due to the β-effect of the
Therefore, the reaction of amine 1 with I2 afforded
initially complex A whose 5-exo- and 6-endo-cycliza-
tion gave rise to heterocycles 2 and 3, respectively. The
heavy iodine atom.5
The assignment of the signals in the 13C NMR
spectra of azatricyclotridecatrienes 3 and 4 was made
9
intramolecular nucleophilic attack in nonpolar solvents
based on the multiplicities of the signals, the results of
calculations from the increments of the chemical shifts,
(
see Table 1) occurs preferentially at the C(2´) atom of
10
the cyclohexenyl substituent, whereas polar solvents fa-
vor the attack at the C(3´) atom.
Unlike cyclization of amine 1, the formation of
regioisomers in the reaction of amine 5 with I2 is
virtually independent of the properties of the solvent.
This reaction afforded exclusively 3-iodo-2,4,6-trimethyl-
and comparison with the published data for substituted
bicyclo[3.1.1]heptanes13 and analogous bridging sys-
tems.14 The anti orientation of the I atom with respect
to the phenyl ring was assigned based on the 1H NMR
spectral data. The bridging H(13) proton gives a signal as
a doublet of doublets of doublets of doublets with the
spin-spin coupling constant of no higher than 2 Hz.
Studies by the double resonance method demonstrated
that two spin-spin coupling constants for the H(13)
proton are caused by coupling with the nodal H(1) and
H(9) protons, whereas two other constants (W con-
1
,2,3,4-tetrahydroquinolines 6 and 7 and quinoline 8
(
the yield of the latter varied from 8 to 20%) (Scheme 2).
The reaction in MeCN also gave rise to diiodo deriva-
tive 9 (4%).
stants) appear due to coupling with the equatorial H (12)
e
Scheme 2
and H (10) protons.15
e
The structures of isomers 6 and 7 were established by
1H NMR spectroscopy. The signals for the H(4) and
H(2) protons are observed as doublets of quartets,
whereas the signal for the H(3) proton is manifested as a
doublet of doublets. The unambiguous assignment of the
Me
Me
Me
Me
4a
I
4
3
I2
6
7
5
8
+
2
1
NaHCO3
8
a
NH2
N
H
Me
signals for the H(2) and H(4) protons was made based
on the two-dimensional heteronuclear 13C-1H COSY
5
R
6
9
: R = H
: R = I
spectrum in which the signals for the C(2) and C(4)
atoms are rather characteristic. The methyl groups at the
C(2) and C(4) atoms in compounds 6 and 7 differ in the
spin-spin coupling constants with the vicinal protons.
The constants for the C(2) and C(4) atoms are 6.3—6.4
and 7.3 Hz, respectively. For compound 7, the spin-spin
coupling constants of the vicinal H(3) proton with H(4)
and H(2) are 10.4 and 10.3 Hz, respectively. These
values are characteristic of the trans-diaxial arrangement
of the protons.15 Consequently, compound 7 has a
structure with the mutual trans configurations of the
substituents at the C(2) and C(3) atoms and at the C(3)
and C(4) atoms. Conformer Å with the equatorial ar-
rangement of the substituents prevails in solution
(Scheme 3). The observed shift of the conformational
equilibrium was confirmed by the results of experiments
performed at different temperatures. Thus, the vicinal
spin-spin coupling constants between the H(3) and H(2)
protons and between the H(3) and H(4) protons were
decreased by 0.2—0.25 Hz as the temperature of the
specimens was increased from 25 to 55 °C due to an
Me
Me
Me
I
Me
+
+
N
H
Me
N
Me
7
8
The structures of compounds 2—9 were established
by NMR spectroscopy. In the spectrum of carbazole 2,
the signal for the H(1) proton has two large spin-spin
coupling constants (12.0 and 9.1 Hz) and one smaller
constant (4.0 Hz). Studies by the double resonance
method demonstrated that the constants equal to 12.0
and 4.0 Hz are caused by vicinal coupling with the
geminal protons at the C(2) atom, whereas the constant
of 9.1 Hz appears due to coupling with the protons at
the C(9a) atom. The large spin-spin coupling constants
are indicative of the trans-diaxial interaction, i.e., the
equilibrium is shifted toward conformer B (see Scheme 1)

4
58
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 3, March, 2001
Gataullin et al.
increase in the fraction of the conformers with the axial
arrangement of the substituents.
In the 13C NMR spectrum of compound 6, the
signals for the C(4) and C(3) atoms are observed at
higher field (at δ 36.1 and 42.4, respectively) compared
to those in the spectrum of compound 7 (at δ 42.8 and
tridecatriene structure depending on the solvent used,
whereas the reaction of 2-(1-methylbut-2-enyl)-4-
methylalanine performed under these conditions gave
rise exclusively to 3-iodine-substituted tetrahydro-
quinolines regardless of the solvent.
4
6.2, respectively).
Experimental
The 1H (300.13 MHz) and 13C (75.47 MHz) NMR spectra
were recorded on a Bruker AM-300 instrument in CDCl3 with
Scheme 3
Me Si as the internal standard. The IR spectra were measured
I
4
Me
Me
He
Me
on a UR-20 instrument. The mass spectra were obtained on an
MÕ 1320 instrument (70 eV). The course of the reaction was
monitored using Silufol UV 254 plates.
Me
Me
He
Ha
Ha
I
He
Procedure for cyclization of alkenylaniline 1. A mixture of
arylamine 1 (0.17 g, 1 mmol), NaHCO3 (1.5 g), and I2 (0.51 g,
2 mmol) in a solvent (10 mL) (see Table 1) was shaken at 20 °C
for 24—130 h. The course of the reaction was monitored by
TLC (a 98 : 2 hexane—MeOH mixture as the eluent). After
completion of the reaction, CH Cl (50 mL) was added. The
N
N
H
Me
H
Ha
C
D
2
2
I
precipitate that formed was filtered off and washed with CH Cl
2
Me
Me
2
Ha
He
(10 mL). The combined filtrates were washed with a 5% aque-
ous solution of Na S O (3½10 mL) and water (1½20 mL) and
Me
He
Ha
2
2
3
Me
He
I
dried over Na SO . The solvent was evaporated in vacuo. The
2
4
N
N
residue was chromatographed (hexane as the eluent) on a
column with SiO (3 g) to isolate the reaction products.
H
Me
H
Me
Ha
2
1R ,4aR ,9aR )-1-Iodo-1,2,3,4,4a,9a-hexahydro-9H-car-
*
*
*
(
E
F
bazole (2). Chromatography of the reaction mixture obtained in
the reaction in CCl4 afforded compound 2 as a brown viscous
oil in a yield of 0.17 g (57%), R 0.60 (CH Cl ). Found (%):
Based on these data, it was concluded that the
substituents at the C(3) and C(4) atoms in compound 6
are in the cis arrangement. It is known10 that interac-
tions between 1,2-cis substituents lead to upfield shifts of
the signals for the carbon atoms to which these substitu-
ents are bound compared to the corresponding signals
observed in the spectra of 1,2-trans compounds. In the
1H NMR spectra of these compounds, the signals for the
methyl groups at the C(4) atom differ most substantially.
The chemical shifts of these signals in isomers 6 and 7
are 1.7 and 1.4 ppm, respectively. The spin-spin cou-
pling constants between the H(3) and H(4) protons are
f
2
2
C, 47.67; H, 4.86; I, 41.87; N, 3.92. C12H14IN. Calculated (%):
C, 48.18; H, 4.72; I, 42.42; N, 4.68. IR, ν/cm–1: 3472 (NH).
1
H NMR, δ: 1.10—2.30 (m, 6 H, 3 CH ), 3.20 (m, 1 H, H(4a));
2
3
3
4
1
.88 (dd, H(9a), JH(9a),H(1) = 9.1 Hz, JH(9a),H(4a) = 7.1 Hz);
.97 (ddd, 1 H, H(1), J1 = 4.0 Hz, J2 = 9.1 Hz, J3 = 12.0 Hz);
.10 (br.s, 1 H, NH); 6.80 (d, 1 H, H(8), J = 7.6 Hz); 6.70 (t,
H, H(6)); 7.10 (d, 1 H, H(5), J = 7.5 Hz); 7.20 (t, 1 H,
H(7)). 13C NMR, δ: 23.2 (C(3)); 23.5 (C(4)); 36.3 (C(2)); 39.0
(C(1)); 42.6 (C(4a)); 69.5 (C(9a)); 110.5 (C(8)); 119.2 (C(6));
1
22.7 (C(5)); 127.4 (C(7)); 129.5 (C(4b)); 149.7 (C(8a)).
(
1S ,9S ,13S )-13-Iodo-2-azatricyclo[7.3.1.02,7]trideca-
*
*
*
3
,5,7-triene (3). Chromatography of the reaction mixture ob-
1
0.4 and 4.0 Hz for compounds 7 and 6, respectively,
tained in the reaction in MeCN afforded compound 3 as a dark
viscous oil in a yield of 0.15 g (49%), Rf 0.50 (CH Cl ).
which is indicative of the different mutual arrangement
of these protons (trans in compound 7 and cis in com-
pound 6). These data suggest that stereoisomer 6 and
diastereomer 7 differ in the orientation of the methyl
group at the C(4) atom. Therefore, compound 6 is a
diastereomer with the trans,cis arrangement of the sub-
stituents at the C(2), C(3), and C(4) atoms and exists in
solutions predominantly as conformer C (see Scheme 3).
2
2
Found (%): C, 48.42; H, 4.23; I, 41.94; N, 4.00. C12H14IN.
Calculated (%): C, 48.18; H, 4.72; I, 42.42; N, 4.68. IR,
ν/cm–1: 3475 (NH). 1H NMR, δ: 1.50—1.90 (m, 4 H, H (10),
a
Ha(12), C(11)H2); 2.30—2.60 (m, 2 H, He(10), He(12)); 3.20
(
m, 1 H, H(1)); 3.70 (dddd, 1 H, H(13), J = 2.1, 2.0, 1.6, and
1
1
.5 Hz); 4.20 (br.s, 1 H, NH); 4.90 (ddd, 1 H, H(9), J = 2.0,
.6, and 4.2 Hz); 6.60 (d, 1 H, H(6), J = 7.3 Hz); 6.80 (t, 1 H,
H(4), J = 7.3 Hz); 7.00 (d, 1 H, H(3), J = 7.3 Hz); 7.10 (t,
H, H(5)). 13C NMR, δ: 16.6 (C(11)); 29.9 (C(12)); 30.1
1
In the H NMR spectrum of 3,8-diiodoquinoline 9,
1
the chemical shifts of the signals for the aliphatic pro-
tons and their spin-spin coupling constants are analo-
gous to those in the spectrum of compound 6. The 13C
NMR spectrum of heterocycle 9 has six signals for the
atoms of the aromatic moiety of the molecule. The
chemical shift for the C(8) atom (83.6 ppm) indicates
that the iodine atom is bound to the C(8) atom.16
To summarize, cyclization of 2-(cyclohex-2-enyl)ani-
line under the action of iodine afforded predominantly
an isomer with either a carbazole or azatricyclo-
(
C(10)); 33.2 (C(13)); 41.3 (C(1)); 51.7 (C(9)); 112.4 (C(6));
118.1 (C(4)); 123.4 (C(2)); 127.2 (C(3)); 127.8 (C(5));
144.3 (C(7)).
*
*
*
(
1S ,9S ,13S )-6,13-Diiodo-2-azatricyclo[7.3.1.02,7]tri-
deca-3,5,7-triene (4). Chromatography of the products, which
were obtained in the reaction performed in MeCN, afforded
compound 4 as a viscous oil in 9% yield, Rf 0.70 (CH Cl ).
Found (%): C, 33.91; H, 3.08; N, 3.30; I, 59.71. C12H13I2N.
Calculated (%): C, 33.91; H, 3.08; I, 59.71; N, 3.30. IR,
ν/cm–1: 3473 (NH). 1H NMR, δ: 1.80—2.00 (m, 4 H, H (10),
2
2
a
H (12), C(11)H ); 2.10—2.30 (m, 2 H, H (10), H (12)); 3.10
a
2
e
e

Cyclization of ortho-(alk-2-enyl)anilines
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 3, March, 2001
459
(
m, 1 H, H(1)); 3.70 (dddd, 1 H, H(13), J = 2.1, 2.0, 1.6, and
.2 Hz); 4.10 (br.s, 1 H, NH); 4.70 (ddd, 1 H, H(9), J = 2.0,
.7, and 4.1 Hz); 6.58 (d, 1 H, H(6), J = 8.0 Hz); 6.90 (s, 1 H,
N, 2.64. C12H I N. Calculated (%): C, 33.75; H, 3.54; I, 59.43;
15 2
1
1
N, 3.28. IR, ν/cm–1: 3479 (NH). 1H NMR, δ: 1.45 (d, 3 H,
C(2)CH , J = 6.4 Hz); 1.40 (d, 3 H, C(4)CH , J = 6.8 Hz);
3
3
H(3)); 7.00 (d, 1 H, H(5)). 13C NMR, δ: 16.5 (C(11)); 30.1
2.20 (s, 3 H, CH ); 2.90 (dq, 1 H, H(4), J
= 4.0 Hz,
H(4),H(3)
3
(
8
(
C(12)); 30.2 (C(10)); 31.4 (C(13)); 40.9 (C(1)); 51.5 (C(9));
0.3 (C(4)); 112.5 (C(6)); 126.3 (C(3)); 123.7 (C(2)); 131.5
C(5)); 144.3 (C(7)).
JH(4),HCH3 = 6.8 Hz); 3.90 (dq, 1 H, H(2), JH(2),H(3) = 8.2 Hz,
JH(2),CH3 = 6.4 Hz); 4.20 (dd, 1 H, H(3), JH(3),H(4) = 4.0 Hz,
JH(2),H(3) = 8.2 Hz); 4.30 (br.s, 1 H, NH); 6.80 (s, 1 H, H(7));
1
3
Procedure for iodocyclization of alkenylaniline 5. The reac-
7.40 (s, 1 H, H(5)). C NMR, δ: 19.9, 21.9, and 24.8 (CH );
3
tion with I was performed and the reaction mixture was worked
up according to the above-described procedure. A mixture of
38.1 (C(4)); 40.6 (C(3)); 51.6 (C(2)); 83.6 (C(8)); 123.7 (C(4a));
127.7 (C(6)); 128.4 (C(5)); 137.5 (C(7)); 139.2 (C(8a)).
2
compounds 6—9 was obtained from compound 5 (1.75 g,
1
0 mmol) and I2 (5.1 g, 20 mmol) in a solvent (benzene,
References
MeCN, CH Cl , CCl , or 1,2-dichloroethane; 30 mL) in a
2
2
4
yield of ∼ 4 g. The mixture of the products was kept at ∼ 20 °C for
two days and treated with CCl4 (5 mL). The crystals of quino-
1. C. Cardillo and M. Orena, Tetrahedron, 1990, 46, 3321.
2. A. Bongini, C. Cardillo, M. Orena, G. Porzi, and S. Sandri,
Chem. Lett., 1988, 87.
line 8 that formed were filtered off, washed with CCl (1—3 mL),
4
and dried in vacuo. The filtrate was concentrated to the mini-
mum volume and chromatographed on a column with SiO2
3. S. R. Wilson and R. A. Sawicki, J. Org. Chem., 1979,
44, 287.
4. S. R. Wilson, R. A. Sawicki, and J. C. Huffman, J. Org.
Chem., 1981, 46, 3887.
5. M. Watanabe, H. Okada, T. Teshima, M. Nogucli, and
A. Kakehi, Tetrahedron, 1996, 52, 2827.
6. R. R. Gataullin, T. V. Kazhanova, F. F. Minnigulov, A. A.
Fatykhov, L. V. Spirikhin, and I. B. Abdrakhmanov, Izv.
Akad. Nauk, Ser. Khim., 2000, 1789 [Russ. Chem. Bull., Int.
Ed., 2000, 49, 1767].
(
50 g) using hexane as the eluent to isolate products 6, 7, and 9.
*
*
*
(
2R ,3R ,4R )-3-Iodo-2,4,6-trimethyl-1,2,3,4-tetrahydro-
quinoline (6) was obtained as an oil in a yield of 1.11 g (37%),
Rf 0.40 (CH Cl ). Found (%): C, 47.67; H, 4.86; I, 41.87;
2
2
N, 4.92. C12H16IN. Calculated (%): C, 47.86; H, 5.36; I, 42.14;
N, 4.65. IR, ν/cm–1: 3474 (NH). 1H NMR, δ: 1.39 (d, 3 H,
C(2)CH , J = 6.4 Hz); 1.42 (d, 3 H, C(4)CH , J = 7.4 Hz);
3
3
2
.25 (s, 3 H, CH ); 2.91 (dq, 1 H, H(4), J
= 4.0 Hz,
H(4),H(3)
3
JH(4),CH3 = 7.4 Hz); 3.84 (dq, 1 H, H(2), JH(2),CH3 = 6.4 Hz,
JH(2),H(3) = 8.4 Hz); 4.35 (dd, 1 H, H(3), JH(3),H(4) = 4.0 Hz,
7. I. B. Abdrakhmanov, V. M. Sharafutdinov, and G. A.
Tolstikov, Izv. Akad. Nauk SSSR, Ser. Khim., 1982, 2160
[Bull. Acad. Sci. USSR, Div. Chem. Sci., 1982, 31 (Engl.
Transl.)].
JH(2),H(3) = 8.4 Hz); 6.40 (d, 1 H, H(8), J
= 8.0 Hz);
H(8),H(7)
1
3
6
2
.86 (d, 1 H, H(7)); 6.94 (s, 1 H, H(5)). C NMR, δ: 20.6,
2.1, 24.8 (3 CH ); 36.1 (C(4)); 42.4 (C(3)); 51.3 (C(2)); 113.8
3
(
1
C(8)); 123.2 (C(4a)); 128.1 (C(7)); 128.3 (C(5)); 128.9 (C(6));
39.4 (C(8a)).
8. I. B. Abdrakhmanov, V. M. Sharafutdinov, N. G. Nigma-
tullin, I. A. Sagitdinov, and G. A. Tolstikov, Izv. Akad.
Nauk SSSR, Ser. Khim., 1982, 1466 [Bull. Acad. Sci. USSR,
Div. Chem. Sci., 1982 (Engl. Transl.)].
9. J. E. Baldwin, J. Chem. Soc., Chem. Comm., 1976, p. 734.
10. E. Pretsch, T. Clerk, J. Seible, and W. Simon, Tables of
Spectral Data for Structure Determination of Organic
Compounds, Springer Verlag, Berlin—Heidelberg—New
York—Tokyo, 1983.
*
*
*
(
2R ,3R ,4S )-3-Iodo-2,4,6-trimethyl-1,2,3,4-tetrahydro-
quinoline (7) was obtained as an oil in a yield of 0.9 g (30%),
Rf 0.50 (CH Cl ). Found (%): C, 47.82; H, 5.40; I, 41.92;
N, 4.00. C12H16IN. Calculated (%): C, 47.86; H, 5.36; I, 42.14;
N, 4.65. IR, ν/cm–1: 3476 (NH). 1H NMR, δ: 1.37 (d, 3 H,
C(2)CH , J = 6.3 Hz); 1.70 (d, 3 H, C(4)CH , J = 7.3 Hz);
2
2
3
3
2
.20 (s, 3 H, CH ); 3.20 (dq, 1 H, H(4), J
= 7.3 Hz,
H(4),CH
3
3
JH(4),H(3) = 10.4 Hz); 3.60 (dq, 1 H, H(2), JH(2),CH3 = 6.3 Hz,
JH(2),H(3) = 10.3 Hz); 4.00 (dd, 1 H, H(3), JH(3),H(2) = 10.3 Hz,
11. L. M. Jackman and S. Sternhell, Application of Nuclear
Magnetic Resonance in Organic Chemistry, Pergamon Press,
Oxford, 1969, p. 236.
12. R. A. Abramovitch and S. S. Singer, J. Org. Chem., 1976,
41, 1712.
J
= 10.4 Hz); 6.50 (d, 1 H, H(8), J = 7.9 Hz); 6.90 (d,
H(3),H(4)
1
2
1
1
H, H(7)); 7.10 (s, 1 H, H(5)). 13C NMR, δ: 20.6, 21.6, and
4.9 (CH ); 42.8 (C(4)); 46.2 (C(3)); 54.2 (C(2)); 114.4 (C(8));
3
24.1 (C(4a)); 128.4 (C(7)); 128.3 (C(5)); 128.9 (C(6));
41.2 (C(8a)).
13. J. K. Whitersell and M. A. Minton, Stereochemical Analysis
1
3
of Alicyclic Compounds by C NMR Spectroscopy, Chapman
and Hale, London—New York, 1987, p. 114.
14. M. Sindler-Kulyk and W. H. Laarhoven, J. Am. Chem. Soc.,
1978, 100, 3819.
2
,4,6-Trimethylquinoline (8) was obtained in a yield of
0
.34 g (20%), m.p. 125 °C. Found (%): C, 83.85; H, 7.32;
N, 7.78. C12H13N. Calculated (%): C, 84.17; H, 7.65; N, 8.18.
1
H NMR, δ: 2.60 (s, 3 H, CH ); 2.90 (s, 3 H, CH ); 3.20 (s,
15. H. Gunter, NMR Spectroscopy. An Introduction, Wiley, New
York—London, 1980.
16. B. I. Ionin, B. A. Ershov, and A. I. Kol´tsov,
YaMR-spektroskopiya v organicheskoi khimii [NMR Spectros-
copy in Organic Chemistry], Khimiya, Leningrad, 1983, 142
(in Russian).
3
3
3
7
H, CH ); 7.50 (s, 1 H, H(3)); 7.80 (d, 1 H, H(8), J = 8.7 Hz);
3
.90 (s, 1 H, H(5)); 8.90 (d, 1 H, H(7), J = 8.7 Hz). 13C NMR,
δ: 20.0, 20.2 è 22.0 (3 CH ); 120.7 (C(3)); 123.6 (C(5)); 123.9
3
(
1
C(8)); 127.0 (C(4a)); 135.9 (C(6)); 136.3 (C(7)); 140.2 (C(4));
54.5 (C(8a)); 155.9 (C(2)).
*
*
*
(
2R ,3R ,4R )-3,8-Diiodo-2,4,6-trimethyl-1,2,3,4-tetra-
hydroquinoline (9) was obtained as an oil in a yield of 0.17 g
4%), R 0.60 (CH Cl ). Found (%): C, 32.83; H, 4.03; I, 58.84;
Received June 26, 2000;
in revised form November 17, 2000
(
f
2
2