One-pot synthesis of 6′-amino-substituted spirooxazines

Article abstract of DOI:10.1055/s-2005-870006

A one-pot synthesis of 6′-amino-substituted spiroindolinonaphth[2,1- b][1,4]oxazines is developed through the condensation of 2-methylene-1,3,3- trimethylindoline derivatives and 1-amino-2-naphthol in the presence of different secondary amines and oxidizing agents using methanol or toluene as the solvent. The main advantage of the method is its simplicity, and starting from readily accessible reagents, it allows the preparation of amino derivatives of spironaphthoxazine with good yields under mild reaction conditions. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2005-870006

1
876
PAPER
One-Pot Synthesis of 6¢-Amino-Substituted Spirooxazines
a
b
b
a
a
S
A
ynthesis of
6
¢
-A
m
.
ino-Substitu
V
ted Spirooxazines. Koshkin, V. Lokshin, A. Samat, S. P. Gromov, O. A. Fedorova*
a
Photochemistry Center of the Russian Academy of Sciences, Novatorov str. 7a, 119421 Moscow, Russia
Fax +7(095)9361255; E-mail: fedorova@photonics.ru
Faculté des Sciences de Luminy, Université de la Méditerranée, UMR 6114 CNRS, 13288 Marseille, France
b
Received 11 November 2004; revised 18 February 2005
ration of the starting 1-nitroso-2-naphthol. Rickwood and
co-workers used some secondary amines as nucleophiles
Abstract: A one-pot synthesis of 6¢-amino-substituted spiroindoli-
nonaphth[2,1-b][1,4]oxazines is developed through the condensa-
tion of 2-methylene-1,3,3-trimethylindoline derivatives and 1-
amino-2-naphthol in the presence of different secondary amines and
for the preparation of 6¢-amino-substituted spironaph-
thoxazines.1
3–16
It was assumed that the reaction involves
oxidizing agents using methanol or toluene as the solvent. The main the nucleophilic addition of secondary amine at position 4
advantage of the method is its simplicity, and starting from readily of the quinone oxime tautomer of 1-nitroso-2-naphthol.
accessible reagents, it allows the preparation of amino derivatives
Subsequent oxidation of intermediate can occur under the
of spironaphthoxazine with good yields under mild reaction condi-
action of a second 1-nitroso-2-naphthol molecule, which
tions.
partially accounts for the low yield.
Key words: spiroindolinonaphth[2,1-b][1,4]oxazine, 2-methylene-
In this paper we describe the synthesis of the 6¢-amino-
subsituted spirooxazines by one-pot condensation of 1-
amino-2-naphthol with substituted 2-methyleneindolines
in the presence of different secondary amines and oxidiz-
ing agent using methanol or toluene as the solvent
(Scheme 1). To evaluate the general validity of the meth-
od and to show its advantages and limitations we varied
the substituents in indoline molecules 1a–d and used dif-
ferent secondary cyclic amines 2a–d.
1
,3,3-trimethylindoline, 1-amino-2-naphthol, one-pot synthesis
Spirooxazines have UV activation properties and thermal
bleaching properties that are convenient for practical ap-
plications. By now, the widely applied procedures for
the synthesis of spirooxazines consist in the condensation
of nitrogen-containing heterocycles with hydroxynitroso
1
–5
3
compounds. Unfortunately, this method affords spiroox-
azines in low yields, even if optimization of experimental Our experiments showed that alicyclic/aliphatic second-
conditions allowed to improve it in some cases.3 The ary amines did not participate in the condensation reac-
spirooxazine molecule can be constructed also by using 1- tion. In the presence of diethylamine or bis(2-
,6
7
–12
amino-2-naphthol as the starting material.
methoxyethyloxy)amine the condensation of 1a with 1-
amino-2-naphthol results in the formation of unsubstitut-
ed spiroindolinonaphth[2,1-b][1,4]oxazine. In contrast,
the method was successfully applied for the preparation of
spirooxazines 3a–c, 4a, 5, and 6 with cyclic amine substit-
Most of the structural modifications of the oxazine frag-
ment in spiro compounds are based on the substitution on
the naphthalene ring. The required group is most com-
monly introduced into this fragment already in the prepa-
.
NH2 HCl
Me Me
Me
Me
RH
R2
R2
HO
N
CH2
2a–d
+
N
N
R1
O
DMSO, Et3N
Solvent
R1
R
3
a–d, 4a,b, 5, 6
1a–d
O
N
N
S
(2a, 3a),
(4a),
1
1
a, 2a, 3a, 4a, 5, 6: R1 = Me, R2 = H, R = N
(5),
N
(6);
N
O
N
b, 2b, 3b: R1 =C16H33, R = H, R =
2
, 4b: R =
;
c, 2c, 3c: R1 = Me, R = MeO, R = N
O
;
N
O
2
1d, 2d, 3d: R = Me,R2 = Cl, R =
1
1
Scheme 1
SYNTHESIS 2005, No. 11, pp 1876–1880
x
x.
x
x
.
2
0
0
5
Advanced online publication: 29.06.2005
DOI: 10.1055/s-2005-870006; Art ID: Z21004SS
Georg Thieme Verlag Stuttgart · New York
©

PAPER
Synthesis of 6¢-Amino-Substituted Spirooxazines
1877
uents at the 6¢-position as shown in Table 1. In a typical able to react with secondary amines by the Michael addi-
14
experiment, a mixture of reagents and dimethyl sulfoxide tion mechanism; the step in which the amino group is in-
was heated in toluene or methanol up to 40 °C. 1-Amino- serted into the molecule remains an open point for future
2
-naphthol and in some experiments bases 1a–c were gen- investigation.
erated in situ from the corresponding salts by addition of
In the formation of 6¢-amino-substituted spironaphthox-
Et N.
8
3
azines, DMSO was used as oxidizing agent. In our exper-
iment to improve the yield of the product 3c, the
commercially available oxidizing reagent Dess–Martin
was used.17 As shown in Table 1, more substantial in-
crease of the yield was found in toluene as the reaction
medium.
Table 1 6¢-Amino-Substituted Spirooxazines 3a–d, 4a,b, 5, and 6
Prepared
1
2
Prod- R
uct
R , R
Yield (%) Yield (%)
in MeOH in Toluene
1
2
81 (60)a 15
3
a
R = Me, R = H
Although in the mechanism of the reaction, formation of
spironaphthoxazine from the 1-amino-2-naphthol and
Fisher’s base has not been described, the involvement of
N
O
1
2
46a
3
3
3
4
b
c
R = C H , R = H
15
7
1
6
33
an intermediate carbonyl derivative was proposed. The
1
2
15 (17)b
0 (12)b
mild reaction conditions allowed us to isolate compound
R = Me, R = Cl
1
13
7
whose structure was established by NMR ( H, C) spec-
1
2
d
a
R = Me, R = OMe
45
13
0
1
13
troscopy, COSY and NOESY ( H, C) methods
(Scheme 2). The NMR investigation showed that, in com-
parison with spiroindolinonaphth[2,1-b][1,4]oxazine 8, in
the aromatic region of 7 the singlet of CH=N group of ox-
azine ring is absent. In aliphatic region a new broad sin-
glet at 4.25 ppm and 2 doublets at 3.6 ppm and 3.8 ppm
had appeared. From NMR analysis, the singlet corre-
sponds to the proton of the hydroxy group at N atom. Two
doublets that form AB system correspond to the protons
1
2
R = Me, R = H
10
N
1
2
4
5
b
R = Me, R = Cl
13
39
0
1
2
R = Me, R = H
17
N
S
1
2
6
R = Me, R = H
19
10
2
¢
connected with C .
N
a
The transformation of compound 7 to the final spironaph-
thoxazine was studied in benzene and methanol. Com-
pound 7 is stable enough in benzene even upon heating at
Compound was prepared from the corresponding heterocyclic salts,
the bases were generated in situ by addition of Et N.
3
b
17
Dess–Martin reagent was used as the oxidizing agent.
8
0 °C for 6 hours. The transformation of 7 to 8 in benzene
is possible only upon irradiation with light at 365 nm.
Regarding the data of Table 1, one can conclude that the
procedure can be employed for the preparation of amino-
substituted spirooxazines starting from readily accessible
reagents. Another important advantage of the procedure is
that the reactions can be carried out under mild conditions.
Compound 7 is not stable in methanol. The dissolution of
7
in methanol results in the formation of 8. Figure 1a
shows the NMR spectrum of 7 in methanol (proton signals
of compound 7 are marked by ‘i’, proton signals of com-
pound 8 are marked by ‘s’). Keeping 7 in methanol causes
the spontaneous transformation into the spirooxazine 8.
Figures 1b,c show the spectra of 7 after keeping of solu-
tion during 7 and 14 days. The intensity of proton signals
of spironaphthoxazine 8 increases with simultaneous de-
creases of proton signals of 7. After 14 days, the solution
contains practically pure spirooxazine 8 (Figure 1c).
The nature of the solvent and the nature and structure of
the amine component have a substantial influence on the
course of the one-pot formation of the 6¢-amino-substitut-
ed spirooxazines. In principle, during the course of the re-
action, the intermediates formed by the condensation of 1-
amino-2-naphthol with substituted 2-methyleneindolines,
as well as spiroindolinonaphth[2,1-b][1,4]oxazines are
HCl
.
Me Me OH
NH2
4
7
10' 9'
10'a
Me Me
4a
5
6
N
OH
Et2NH
3
11'
2
'
8'
CH2 +
Et3N, DMSO
toluene
N
O
N
7a
6'a
7'
4
'a
Me
Me
6'
7
Me Me
4
7
10' 9'
10'a
4
a
N
,
methanol
5
3
11'
2
'
8'
or hν in benzene
6
N
O
7
a
6'a
7'
4
'a
Me
6
'
8
Scheme 2
Synthesis 2005, No. 11, 1876–1880 © Thieme Stuttgart · New York

1
878
A. V. Koshkin et al.
PAPER
1
Figure 1 H NMR spectra (Bruker, 25 °C, 500 Hz) of compound 7 in CD OD: a) freshly prepared; b) after keeping for 7 days in CD OD;
3
3
c) after keeping for 14 days in CD OD.
3
Thus, compound 7 can be considered as the direct precur- spectively); 2D homonuclear NOESY spectra was used to assign
the proton and carbon signals. Chemical shifts are expressed in parts
per million downfield from was used as solvent for all probes.
sor of the spirooxazine 8. The formation of 7 in course of
the reaction condensation is an important fact for under-
standing the mechanism of the spironaphthoxazine forma- Melting points (°C) were measured in capillary tubes on a Büchi
5
10 apparatus and are uncorrected. TLC was performed on 0.2 mm
tion. Evidently, the reaction includes the oxidation of the
-amino-2-naphthol, condensation of the oxidation prod-
precoated plates of Silica gel 60 F-254 (Merck). Visualization was
made with UV (254 and 365 nm). Silica gel 60 Merck with 0.06–
1
uct with Fisher’s base to form 7, and thermal or photo-in-
duced dehydration of 7 resulting in the formation of the
0
.20 mm particle size was used for preparative column chromatog-
raphy. Elemental analyses were performed by the Microanalytical
spironaphthoxazine 8. The possibility of 7 for easy trans- Center of the University of Aix-Marseille III.
formation under irradiation or heating to photochromic
compound 8 can be considered as promising for practical
applications.
The identification of previously reported reaction products were
1
made by H NMR spectroscopy and melting points comparison with
literature data. Elemental analyses data are presented also for
known compounds for which these data have not been given in the
literature.
In summary, the condensation of methylene-substituted
heterocyclic bases with 1-amino-2-naphthol in presence
of cyclic secondary amines and oxidizing agent can be
Spirooxazines 3a–d, 4a,b, 5, 6; General Procedure
successfully applied to the synthesis of spirooxazines sub- Indoline base 1a–d (1 mmol), 1-aminonaphthol hydrochloride (1.1
stituted by cyclic amine at 6¢-position. The yields of the mmol), secondary amine 2a–d (1.2 mmol), Et
N (1.1 mmol) and
DMSO (or Dess–Martin reagent, 3 mmol) were dissolved in MeOH
or toluene (15 mL). If the bases were generated in situ from corre-
3
products depend on the nature and structure of the second-
ary cyclic amines. The method is simple, starts from
readily accessible reagents, and allows to prepare amino
derivatives in moderate to good yields.
sponding salts, Et N (1.5 equiv) was added per acid equivalent. The
mixture was stirred for 20 h at 40 °C. After the reaction was over,
the product was purified by column chromatography on silica gel
3
using pentane–Et O mixture as eluent (Table 1).
2
Compounds 1a–d, 2a–d and Dess–Martin periodinane were com-
mercially available (Aldrich). Solvents were used without future
purification and dried on molecular sieves, if necessary.
1H NMR spectra were recorded on Bruker BM 250 P spectrometer
1
,3,3-Trimethyl-6¢-morpholinospiro(indolino-2,3¢-
[
3H]naphth[2,1-b]oxazine) (3a)
Mp 198–200 °C (Lit. mp 196 °C).
1
4
(
250 MHz) and on a Bruker DRX500 instrument (500.13 MHz, re-
1
-Hexadecyl-3,3-dimethyl-6-morpholinospiro(indolino-2,3¢-
spectively) as solutions in CDCl , DMSO-d or CD CN using the
solvent as an internal reference (7.27, 2.50 and 1.96 ppm for H, re-
3
6
3
[3H]naphth[2,1-b]oxazine) (3b)
Violet oil.
1
Synthesis 2005, No. 11, 1876–1880 © Thieme Stuttgart · New York

PAPER
Synthesis of 6¢-Amino-Substituted Spirooxazines
1879
1
H NMR (CDCl , 30 °C, 250 MHz): d = 0.88 (t, 3 H, CH J = 6.5
1,3,3-Trimethyl-6¢-thiomorpholinospiro(indolino-2,3¢-
[3H]naphth[2,1-b]oxazine) (5)
Mp 188–189 °C (Lit. mp 184–185 °C).
3
3,
Hz), 1.23 (m, 26 H, 13 CH ), 1.34 [s, 6 H, C(CH ) ], 1.63 (m, 2 H,
CH ), 3.07 [m, 4 H, N(CH ) ], 3.14 (d, 2 H, NCH , J = 7.5 Hz), 3.95
2
3 2
1
4
2
2
2
2
[
m, 4 H, O(CH ) ], 6.59 (m, 2 H, H-5¢, H-7), 6.87 (dd, 1 H, H-5,
1
2
2
H NMR (CDCl , 30 °C, 250 MHz): d = 1.35 [s, 6 H, C(CH ) ], 2.75
3
3 2
J = 7.3, 7.4 Hz), 7.08 (d, 1 H, H-4, J = 7.1 Hz), 7.19 (dd, 1 H, H-6,
J = 7.6, 7.6 Hz), 7.38 (ddd, 1 H, H-8¢, J = 8.2, 8.2, 1.3 Hz), 7.55
(
6
(
7
s, 3 H, NCH ), 2.89 [m, 4 H, N(CH ) ], 3.29 [m, 4 H, S(CH ) ],
3 2 2 2 2
.59 (m, 2 H, H-7, H-5¢), 6.90 (dd, 1 H, H-5, J = 7.4, 7.3 Hz), 7.09
d, 1 H, H-4, J = 7.1 Hz), 7.22 (ddd, 1 H, H-6, J = 7.6, 7.6, 1.3 Hz),
.41 (ddd, 1 H, C-8¢, J = 7.1, 7.0, 1.2 Hz), 7.55 (ddd, 1 H, H-9¢,
(
ddd, 1 H, H-9¢, J = 8.4, 8.1, 1.3 Hz), 7.65 (s, 1 H, H-2¢), 8.04 (d, 1
H, H-7¢, J = 8.1 Hz), 8.54 (d, 1 H, H-10¢, J = 8.4 Hz).
Anal. Calcd for C H N O : C, 78.93; H, 9.21; N, 6.73. Found: C,
7
J = 7.1, 7.0, 1.2 Hz), 7.65 (s, 1 H, H-2¢), 8.01 (d, 1 H, H-7¢, J = 8.2
Hz), 8.53 (d, 1 H, H-10¢, J = 8.2 Hz).
4
1
57
3
2
8.84; H, 9.30; N, 6.69.
Anal. Calcd for C H N OS: C, 72.69; H, 6.34; N, 9.78. Found: C,
2
6
27
3
5
-Chloro-1,3,3-trimethyl-6¢-morpholinospiro(indolino-2,3¢-
7
2.41; H, 6.43; N, 9.71.
[
3H]naphth[2,1-b]oxazine) (3c)
1
4
Mp 205–207 °C (Lit. mp 196 °C).
6
¢-Indolino-1,3,3-trimethylspiro(indolino-2,3¢-[3H]naphth[2,1-
1
H NMR (CDCl , 30 °C, 250 MHz): d = 1.34 [s, 6 H, C(CH ) ], 2.73
s, 3 H, NCH ), 3.08 [m, 4 H, N(CH ) ], 3.95 [m, 4 H, O(CH ) ],
b]oxazine) (6)
Mp 250–252 °C (Lit. mp 231–233 °C) .
3
3 2
1
4
(
3
2 2
2 2
6
4
.48 (d, 1 H, H-7, J = 8.2 Hz), 6.59 (s, 1 H, H-5¢), 7.04 (d, 1 H, H-
1
H NMR (CDCl , 30 °C, 250 MHz): d = 1.36 [s, 6 H, C(CH ) ], 2.77
3
3 2
, J = 2.1 Hz), 7.16 (dd, 1 H, H-6, J = 8.2, 2.2 Hz), 7.39 (ddd, 1 H,
(
1
s, 3 H, NCH ), 3.17 (m, 2 H, CH ), 3.90 (m, 2 H, NCH ), 6.28 (d,
3
2
2
H-8¢, J = 8.2, 8.2, 1.2 Hz), 7.57 (ddd, 1 H, H-9¢, J = 8.2, 8.2, 1.2
Hz), 7.62 (s, 1 H, H-2¢), 8.05 (d, 1 H, H-7¢, J = 8.1 Hz), 8.55 (d, 1
H, H-10¢, J = 8.4 Hz).
H, H-7¢¢, J = 7.7 Hz), 6.58 (d, 1 H, H-7, J = 7.7 Hz), 6.74 (dd, 1
H, H-5¢¢, J = 6.5, 6.5 Hz), 6.92 (m, 3 H, H-5, H-5¢, H-4¢¢), 7.09 (d, 1
H, H-4, J = 8.1 Hz), 7.21 (dd, 2 H, H-6, H-6¢¢, J = 8.0, 7.6 Hz), 7.34
(ddd, 1 H, H-8¢, J = 8.4, 8.2, 1.3 Hz), 7.60 (ddd, 1 H, H-9¢,
J = 8.1, 8.3, 1.3 Hz), 7.69 (s, 1 H, H-2¢), 7.96 (d, 1 H, H-7¢, J = 8.1
Hz), 8.61 (d, 1 H, H-10¢, J = 8.4 Hz).
Anal. Calcd for C H ClN O : C, 69.71; H, 5.85; N, 9.38. Found:
C, 69.63; H, 5.91; N, 9.35.
26
26
3
2
5
-Methoxy-1,3,3-trimethyl-6¢-morpholinospiro(indolino-2,3¢-
Anal. Calcd for C H N O: C, 80.87; H, 6.11; N, 9.43. Found: C,
8
3
0
27
3
[
3H]naphth[2,1-b]oxazine) (3d)
0.72; H, 6.18; N, 9.39.
1
4
Mp 170–172 °C (Lit. mp 172–173 °C).
1
H NMR (CDCl , 30 °C, 250 MHz): d = 1.35 (s, 3 H, CH ), 1.36 (s,
Compound 7
3
3
3
H, CH ), 2.70 (s, 3 H, NCH ), 3.06 [m, 4 H, N(CH ) ], 3.80 (s, 3
2-Methylene-1,3,3-trimethylindoline (1 mmol), 1-aminonaphthol
3
3
2 2
H, OCH ), 3.94 [m, 4 H, O(CH ) ], 6.48 (d, 1 H, H-7, J = 8.7 Hz),
hydrochloride (1.1 mmol), diethylamine (1.2 mmol), Et N (1.1
3
2 2
3
6
.63 (s, 1 H, H-5¢), 6.74 (m, 2 H, H-4, H-6), 7.38 (dd, 1 H, H-8¢,
mmol) and DMSO (3 mmol) were dissolved in toluene (15 mL).
The mixture was stirred for 20 h at r.t. After the reaction was over,
the product was purified by column chromatography on silica gel
J = 7.2, 7.8 Hz), 7.57 (dd, 1 H, H-9¢, J = 7.6, 7.3 Hz), 7.64 (s, 1 H,
H-2¢), 8.05 (d, 1 H, H-7¢, J = 8.3 Hz), 8.55 (d, 1 H, H-10¢, J = 8.6
Hz).
(Merck 60 with 0.06–0.20 mm particles) using pentane–Et O mix-
2
ture as eluent; yield: 26%; mp 167–169 °C (dec.).
Anal. Calcd for C H N O : C, 73.11; H, 6.59; N, 9.47. Found: C,
2
7
29
3
3
1
7
3.01; H, 6.68; N, 9.39.
H NMR (CDCl , 30 °C, 500 MHz): d = 1.40 (s, 3 H, CH ), 1.45 (s,
3
3
3
H, CH ), 2.94 (s, 3 H, NCH ), 3.60 (d, 1 H, H-2¢, J = 11.8 Hz),
3
3
1
,3,3-Trimethyl-6¢-piperidinospiro(indolino-2,3¢-
3.80 (d, 1 H, H-2¢, J = 11.8 Hz), 4.25 (br s, 1 H, NOH), 6.65 (d, 1
H, H-7, J = 7.4 Hz), 6.88 (ddd, 1 H, H-5, J = 6.9, 6.7 Hz, 0.9 Hz),
7.11 (m, 2 H, H-4, H-5¢), 7.19 (ddd, 1 H, H-6, J = 7.4, 7.1, 1.3 Hz),
7.31 (d, 1 H, H-6¢, J = 8.6 Hz), 7.38 (ddd, 1 H, H-8¢, J = 7.1, 6.6, 1.4
Hz), 7.49 (ddd, 1 H, H-9¢, J = 6.7, 7.1, 1.3 Hz), 7.72 (d, 1 H, H-10¢,
J = 8.0 Hz), 7.8 (d, 1 H, H-7¢, J = 7.6 Hz).
[
3H]naphth[2,1-b]oxazine) (4a)
Mp 213–215 °C (Lit. mp 238–239 °C).
1
4
1
H NMR (CDCl , 30 °C, 250 MHz): d = 1.35 [s, 6 H, C(CH ) ], 1.62
3
3 2
(
m, 2 H, CH ) 1.80 (m, 4 H, 2 CH ) 2.76 (s, 3 H, NCH ) 3.01 [m, 4
2 2 3
H, N(CH ) ], 6.57 (m, 2 H, H-5¢, H-7), 6.89 (dd, 1 H, H-5, J = 7.4,
2
2
1
4
8.1 Hz), 7.09 (d, 1 H, H-4, J = 7.1 Hz), 7.22 (ddd, 1 H, H-6, J = 7.7,
7.6, 1.3 Hz), 7.37 (ddd, 1 H, H-8¢, J = 8.2, 8.2, 1.3 Hz), 7.54 (ddd,
1 H, H-9¢, J = 8.2, 8.2, 1.3 Hz), 7.62 (s, 1 H, H-2¢), 8.02 (d, 1 H, H-
7¢, J = 8.2 Hz), 8.53 (d, 1 H, H-10¢, J = 8.5 Hz).
C NMR (CDCl , 30 °C, 500 MHz): d = 21.47 (CH ), 25.43 (CH ),
3
3
3
29.34 (NCH ), 42.97 (C-2¢), 49.18 (C-3), 99.60 (C-2), 106.99 (C-7),
3
118.32 (C-5¢), 118.67 (C-10¢), 118.98 (C-5), 119.95 (C-6¢), 121.31
(C-4), 123.19 (C-8¢), 123.84 (C-10¢a), 124.93 (C-11¢), 125.28 (C-
9
1
¢), 127.66 (C-6), 128.57 (C-7¢), 128.94 (C-6¢a), 137.29 (C-4a),
41.63 (C-4¢a), 149.09 (C-7a).
Anal. Calcd for C H N O: C, 78.80; H, 7.10; N, 10.21. Found: C,
27
29
3
7
8.93; H, 7.04; N, 10.19.
+
MS: m/z (%) = 369 (30, [M – H O]), 329 (25), 291 (2), 277 (100),
2
5
-Chloro-1,3,3-trimethyl-6¢-piperidinospiro(indolino-2,3¢-
259 (1), 241 (7), 223 (10), 215 (8), 201 (2), 196 (4).
[
3H]naphth[2,1-b]oxazine) (4b)
1
4
Mp 227–229 °C (Lit. mp 220–222 °C).
Acknowledgment
1
H NMR (CDCl , 30 °C, 250 MHz): d = 1.34 [s, 6 H, C(CH ) ], 1.62
m, 2 H, CH ), 1.80 [m, 4 H, N(CH ) ], 2.72 (s, 3 H, NCH ), 2.99
3
3 2
(
The study was supported by the INTAS YSF 2001/2-180, PICS
705, RFBR (Grant 02-03-33058) and program ‘Integration’ of Mi-
nistry for Sciences and High Education of Russian Federation. One
of the author (A. V. Koshkin) received a Ph.D. grant support from
the ‘Reseau Formation-Recherche Franco-russe’ of the French Mi-
nistry for Education and Research.
2
2 2
3
(
m, 4 H, 2 CH ), 6.46 (d, 1 H, H-7, J = 8.2 Hz), 6.55 (s, 1 H, H-5¢),
2
7
7
8
.02 (d, 1 H, H-4, J = 2.1 Hz), 7.15 (dd, 1 H, H-6, J = 8.2, 2.1 Hz),
.37 (ddd, 1 H, H-8¢, J = 8.2, 6.9, 1.3 Hz), 7.51 (m, 2 H, H-9¢, H-2¢),
.03 (d, 1 H, H-7¢, J = 8.3 Hz), 8.51 (d, 1 H, H-10¢, J = 8.3 Hz).
Anal. Calcd for C H ClN O: C, 72.71; H, 6.33; N, 9.42. Found: C,
27
28
3
7
2.58; H, 6.41; N, 9.38.
Synthesis 2005, No. 11, 1876–1880 © Thieme Stuttgart · New York

1
880
A. V. Koshkin et al.
PAPER
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Synthesis 2005, No. 11, 1876–1880 © Thieme Stuttgart · New York