A convenient procedure for preparation of 1-(1-aminoalkyl)-1-cyclopropanols from N-benzyl α-amino acid esters

Article abstract of DOI:10.1023/A:1013158900003

The reaction of N-benzyl α-amino acid ethyl esters with ethylmagnesium bromide in the presence of a catalytic amount of titanium tetraisopropoxide leads to formation of the corresponding 1-aminoalkyl-1-cyclopropanols in high yields. Hydrogenation of the l

Full text of DOI:10.1023/A:1013158900003

Russian Journal of Organic Chemistry, Vol. 37, No. 9, 2001, pp. 1238 1243. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 9, 2001,
pp. 1306 1311.
Original Russian Text Copyright
2001 by Lysenko, Kulinkovich.
A Convenient Procedure for Preparation
of 1-(1-Aminoalkyl)-1-cyclopropanols from N-Benzyl
-Amino Acid Esters
I. L. Lysenko and O. G. Kulinkovich
Byelorussian State University, pr. Skoriny 4, Minsk, 220050 Belarus
Received January 31, 2001
Abstract The reaction of N-benzyl -amino acid ethyl esters with ethylmagnesium bromide in the presence
of a catalytic amount of titanium tetraisopropoxide leads to formation of the corresponding 1-aminoalkyl-
1-cyclopropanols in high yields. Hydrogenation of the latter over palladium catalyst ensures selective removal
of one or two protecting benzyl groups from the nitrogen atom.
1-Aminoalkyl-substituted cyclopropanols and their
derivatives exhibit various kinds of biological activity.
For example, an opioid -agonist Bremazocine [1]
containing an 1-aminomethylcyclopropanol moiety
is capable of increasing the concentration of cortico-
sterol in blood plasma [2], and 2-amino-2-(1-hydroxy-
cyclopropyl)acetic acid (Cleonine) is a component of
the natural antibiotic Cleomycin [3]. 1-Aminoalkyl-1-
cyclopropanols are usually synthesized by the action
of primary or secondary amines on oxaspiropentane
[4] or via transformations of cyclopropanone deriva-
tives [5]. In the present communication we describe
an efficient procedure for preparation of 1-(1-amino-
alkyl)-1-cyclopropanols from N-substituted -amino
acid esters and ethylmagnesium bromide in the pres-
ence of titanium tetraisopropoxide [6]. This reaction
was successfully used previously in the synthesis of
substituted 1-alkylcyclopropanols containing alkoxide
and acetal moieties [7], as well as of those possessing
halogen atoms in the alkyl group [8]. There are
published data on intramolecular cyclopropanation of
N-allyl -amino acid esters [9].
N,N-Dibenzylglycine ethyl ester (Ia) and ethyl
esters derived from chiral (Ib Id) and racemic amino
acids (Ie Ig) were brought into reaction with an ether
solution of 3 equiv of ethylmagnesium bromide con-
taining 0.2 equiv of titanium tetraisopropoxide [6].
As a result, the corresponding 1-(1-dibenzylamino-
alkyl)-1-cyclopropanols (IIa IIg) were formed in high
yield (Scheme 1). When the reaction was performed
with a smaller amount of ethylmagnesium bromide or
catalyst, the yield of the target product diminished
because of reduced conversion or formation of diethyl-
carbinols via addition of ethylmagnesium bromide at
the ester group. The yields of compounds IIa and IIe
from N,N-dibenzylglycine and N,N-dibenzyl- -alanine
isopropyl esters were lower by 10 15%, and a part
of the initial ester remained unchanged.
We have developed a convenient (from the pre-
parative viewpoint) procedure for isolation of 1-(1-di-
benzylaminoalkyl)-1-cyclopropanols IIa IIg, which
allowed us to obtain sufficiently pure products
without chromatographic purification. When the reac-
tion was complete, the mixture was treated with
2 M hydrochloric acid at 0 C, 5 equiv of the acid per
1 equiv of the initial ester being taken. As a result,
1-(1-dibenzylaminoalkyl)-1-cyclopropanols IIa IIg
in the form of the corresponding hydrochlorides
(which are insoluble in diethyl ether and water) were
separated as an oily material which crystallized in
some cases. Solid hydrochlorides of IIa, IIc IIe, and
IIg were filtered off and washed with a small amount
of 1 M hydrochloric acid and with ether. Free bases
IIa, IIc IIe, and IIg were isolated by treatment of
the corresponding hydrochlorides with a solution of
sodium hydrogen carbonate, followed by extraction
with methylene chloride; the extract was dried and
evaporated. The yield of 1-(1-dibenzylaminoalkyl)-1-
cyclopropanols IIa, IIc IIe, and IIg with a purity
1
of no less than 95% (according to the H NMR data)
was about 80%. Noncrystallizable hydrochlorides of
IIb, IId, and IIf were dissolved in methylene chloride
and were then treated in a similar way. In this
case products IIb IIg contained more than 90% of
the main substance (1H NMR). 1-(1-Dibenzylamino-
alkyl)-1-cyclopropanols IIa IIg are viscous oily
1070-4280/01/3709-1238$25.00 2001 MAIK Nauka/Interperiodica

A CONVENIENT PROCEDURE FOR PREPARATION OF 1-(1-AMINOALKYL)-. . .
1239
Scheme 1.
Ia, IIa, R = H, R = PhCH2; (S)-Ib, (S)-IIb, R = CH3, R = PhCH2; (S)-Ic, (S)-IIc, R = iso-C3H7, R = PhCH2; (S)-Id, (S)-IId,
R = iso-C4H9, R = PhCH2; rac-Ie, rac-IIe, R = C2H5, R = PhCH2; rac-If, rac-IIf, R = CH3, R = PhCH2; rac-Ig, rac-IIg, R =
iso-C3H7, R = PhCH2; rac-Ih, rac-IIh, RR = (CH2)3; rac-Ii, rac-IIi, RR = (CH2)4.
1
substances which turn dark on exposure to air. Their
yields and physical properties are summarized in
Table 1. Stretching vibrations of the hydroxy group
in the IR spectra of compounds IIa IIg were observed
groups in the region 3200 3500 cm ), and elemental
analysis (Table 2).
Scheme 2.
1
in the region 3300 3600 cm .
However, we failed to apply the same procedure
to the synthesis of cyclopropanols from N-benzyl-
proline ethyl ester (Ih) and N-benzylpipecolic acid
ethyl ester (Ii). Under similar conditions we obtained
complex mixtures of products, presumably due to
adsorption of the catalyst on abundant precipitate
liberated during the process. We succeeded in avoid-
ing separation of the solid product by carrying out
the reaction in boiling tetrahydrofuran with 4 equiv of
ethylmagnesium bromide and 0.25 equiv of titanium
tetraisopropoxide. Compounds IIh and IIi were
isolated by column chromatography on silica gel
using benzene ether as eluent; these are viscous
yellowish oily substances which solidify on cooling.
The IR spectra of IIh and IIi contain characteristic
absorption bands of the hydroxy group at 3400
IIIa, R = R = H; (S)-IIIb, R = CH3, R = H; (S)-IIIc,
R = iso-C3H7, R = H; (S)-IIId, R = iso-C4H9, R = H;
rac-IIIe, R = C2H5, R = H; IVa, R = H, R = PhCH2;
(S)-IVb, R = CH3, R = PhCH2; (S)-IVc, R = iso-C3H7,
R = PhCH2; (S)-IVd, R = iso-C4H9, R = PhCH2; rac-IVe,
R = C2H5, R = PhCH2; rac-IVf, R = CH3, R = PhCH2;
rac-IVg, R = iso-C3H7, R = PhCH2.
Thus, the cyclopropanation of N,N-dibenzyl
-amino acid esters Ia Ig by the action of ethyl-
magnesium bromide in the presence of titanium tetra-
isopropoxide with subsequent removal of the benzyl
protection is an efficient method for preparation of
both racemic and optically active 1-(1-aminoalkyl)-
1-cyclopropanols IIIa IIIe. The procedure is also
applicable to the synthesis of cyclopropanols from
heterocyclic amino acids.
1
1
3500 cm . The yields, H NMR spectral data, and
elemental analyses of cyclopropanols IIh and IIi are
given in Table 1.
1-(1-Dibenzylaminoalkyl)-1-cyclopropanols IIa IIe
were deprotected by catalytic hydrogenation over
palladium hydroxide on charcoal [10]. The reaction
was complete after absorption of 2 equiv of hydrogen,
and 1-(1-aminoalkyl)-1-cyclopropanols IIIa IIIe
were formed in quantitative yield (Scheme 2). In the
hydrogenation of crude hydrochlorides of 1-(1-di-
benzylaminoalkyl)-1-cyclopropanols IIa IIg, which
was performed under the same conditions, only
1 equiv of hydrogen was absorbed. Removal of the
solvent, followed by treatment with alkali, gave
1-(1-benzylaminoalkyl)-1-cyclopropanols IVa IVg
as the only product. The structure of aminoalkylcyclo-
EXPERIMENTAL
1
The H NMR spectra of compounds II IV as solu-
tions in CDCl3 were recorded on a Bruker AC-200
spectrometer at 200 MHz. The IR spectra of com-
pounds IIIa and IVa were measured on a Specord
75IR instrument from solutions in chloroform; com-
pounds IIa IIi, IIIb IIIe, IVa, IVb, IVd, and IVe
were examined as thin films using a Perkin Elmer
1000 FTIR spectrometer. Diethyl ether and tetrahydro-
furan were dried and distilled over metallic sodium.
N,N-Dibenzyl amino acid ethyl esters Ia Ig [11],
N-benzylproline ethyl ester (Ih) [12], and N-benzyl-
1
propanols III and IV was proved by H NMR spec-
troscopy (signals of protons of the cyclopropane ring
were observed in the region 0.2 0.8 ppm), IR spec-
troscopy (broad absorption bands of the OH and NH
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 9 2001

1240
Table 1. Yields, spectral parameters, and elemental analyses of 1-(1-aminoalkyl)-1-cyclopropanols IIa IIi
Found, % Calculated, %
LYSENKO, KULINKOVICH
Comp. Yield, [ ]1D7,a
1H NMR spectrum, , ppm (J, Hz)
Formula
no.
%
deg
C
H
C
H
IIa
90
0.32 0.42 m (2H), 0.72 0.82 m (2H), 2.63 s 80.76
(2H), 3.40 br.s (1H), 3.72 s (4H), 7.20
7.40 m (10H)
8.87
C18H21NO 80.86
C19H23NO 81.10
C21H27NO 81.51
7.92
IIb
IIc
88
92
40
14
0.28 0.40 m (1H), 0.64 0.72 m (3H), 0.84 d 81.30
(3H, 7), 3.26 q (1H, 7), 3.36 d (2H, 14),
4.00 d (2H, 14), 7.14 7.44 m (10H)
8.33
8.88
8.24
8.79
0.22 0.38 m (1H), 0.48 0.64 m (1H), 0.72 81.45
1.00 m (2H), 1.02 d (3H, 7), 1.16 d (3H,
7), 1.78 d (1H, 10), 2.20 2.48 m (1H),
3.5 br.s (1H), 3.88 d (2H, 14), 4.12 d (2H,
14), 7.14 7.48 m (10H)
IId
IIe
95
85
23
0.46 0.82 m (4H), 0.84 d (3H, 6), 0.92 d 81.73
(3H, 6), 0.94 1.10 m (1H), 1.50 1.80 m
(2H), 2.82 d.d (1H, 7. 6), 3.5 br.s (1H),
3.57 d (2H, 14), 3.97 d (2H, 14), 7.18
7.36 m (10H)
8.98
8.62
C22H29NO 81.69
9.04
8.53
0.46 0.70 m (3H), 0.72 0.82 m (1H), 1.02 t 81.20
(3H, 7.5), 1.12 1.36 m (1H), 1.64 1.90 m
(1H), 2.68 t (1H, 6.5), 3.18 3.40 s (1H),
3.64 d (2H, 14), 4.00 d (2H, 14), 7.16
7.38 m (10H)
C20H25NO 81.31
IIf
90
92
0.28 0.40 m (1H), 0.64 0.72 m (3H), 0.84 d 80.98
(3H, 7), 3.26 q (1H, 7), 3.36 d (2H, 14),
4.00 d (2H, 14), 17.14 7.44 m (10H)
8.27
8.67
C19H23NO 81.10
C21H27NO 81.51
8.24
8.79
IIg
0.22 0.38 m (1H), 0.48 0.64 m (1H), 0.72 81.60
1.00 m (2H), 1.02 d (3H, 7), 1.16 d (3H,
7), 1.78 d (1H, 10), 2.20 2.48 m (1H),
3.5 br.s (1H), 3.88 d (2H, 14), 4.12 d (2H,
14), 7.14 7.48 m (10H)
IIhb
45
60
0.28 0.42 m (1H), 0.42 0.54 m (1H), 0.74 77.59
0.92 m (2H), 1.60 2.20 m (5H), 2.20
2.36 m (1H), 2.96 3.08 m (1H), 3.30 d
(1H, 13), 3.54 br.s (1H), 4.50 d (1H, 13),
7.20 7.42 m (5H)
8.70
9.25
C14H19NO 77.38
8.81
9.15
IIib
0.12 0.20 m (1H), 0.32 0.46 m (1H), 0.48 77.95
0.86 m (1H), 0.86 1.08 m (1H),1.15
1.64 m (4H), 1.72 1.98 m (4H), 3.84
3.96 m (1H), 2.90 d (1H, 13), 3.24 br.s
(1H), 4.74 d (1H, 14), 7.20 7.42 m (5H)
C15H21NO 77.88
a
c = 10, Et2O.
b
The reaction was carried out in boiling tetrahydrofuran using 4 equiv of EtMgBr and 0.25 equiv of Ti(OPr-i)4.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 9 2001

A CONVENIENT PROCEDURE FOR PREPARATION OF 1-(1-AMINOALKYL)-. . .
1241
Table 2. Yields, spectral parameters, and elemental analyses of 1-(1-aminoalkyl)-1-cyclopropanols IIIa IIIe and
IVa IVg
Found, %
Calculated, %
Comp. Yield,
[ ]1D7, deg
1H NMR spectrum, , ppm (J, Hz)
Formula
no.
%
C
H
C
H
IIIa
IIIb
95
95
0.42 0.52 m (2H), 0.72 0.82 m (2H), 55.02 10.47
2.76 s (2H), 3.46 br.s (3H)
C4H9NO
55.15 10.41
59.37 10.96
5
0.32 0.42 m (2H), 0.60 0.70 m (2H), 59.24 11.09
1.06 d (3H, 7), 2.38 q (1H, 7),
2.68 br.s (3H)
C5H11NO
(c = 4, MeOH)
IIIca
IIId
95
98
18
0.20 0.38 m (1H), 0.50 6.04 m (2H), 65.25 11.76
0.82 1.00 m (1H), 0.96 d (3H, 7),
C7H15NO
C8H17NO
65.07 11.70
67.09 11.96
(c = 4, MeOH)
1.02 d (3H, 7), 1.78 d (1H, 9),
1.80 2.04 m (1H), 2.80 br.s (3H)
7
0.32 0.50 m (2H), 0.6 0.7 m (1H), 66.86 12.10
0.7 0.8 m (1H), 0.86 d (3H, 7),
0.92 d (3H, 7), 1.40 t (2H, 7),
1.58 1.82 m (1H), 2.28 t (1H, 7),
2.44 br.s (3H)
(c = 3.7,
MeOH)
IIIe
95
0.36 0.60 m (2H), 0.66 0.92 m (2H), 62.81 11.45
1.00 t (3H, 7.5), 1.40 1.64 m
C6H13NO
62.57 11.38
(1H), 1.64 1.86 m (1H), 2.23 d.d
(1H, 7.5, 6.5), 3.4 br.s (3H)
IVab
IVb
90
98
0.36 0.48 m (2H), 0.70 0.82 m (2H), 74.69
2.70 s (2H), 3.22 br.s (2H), 3.80 s
(2H), 7.22 7.38 m (5H)
8.48
8.89
C11H15NO 74.54
C12H17NO 75.35
8.53
8.96
14.2
(c = 10, Et2O)
0.26 0.38 m (1H), 0.38 0. 50 m 75.25
(1H), 0. 70 0.82 m (2H), 1.10 d
(3H, 6. 5), 2.28 q (1H, 6.5), 2.40
3.00 s (2H), 3.82 d (2H, 13),
3.90 d (2H, 13), 7.20 7.40 m (5H)
IVc
IVd
IVe
90
95
90
34.4
(c = 5, CH2Cl2)
0.34 0.58 m (2H), 0.66 0.78 m (1H), 76.70
0.86 1.00 m (1H), 1.04 d (3H, 7),
1.06 d (3H, 7), 1.84 d (1H, 7),
1.98 m (1H), 2.40 br.s (2H),
3.78 d (1H, 13), 4.08 d (1H, 13),
7.20 7.40 m (5H)
9.70
C14H21NO 76.67
C15H23NO 77.21
C13H19NO 76.06
9.65
9.93
9.33
22
0.24 0.40 m (1H), 0.40 0.54 m (1H), 77.15 10.05
0.70 0.86 m (5H), 0.92 d (3H,
6.5), 1.36 1.76 m (3H), 2.11 d.d
(1H, 8.5, 5), 2.4 br.s (2H), 3.77 d
(1H, 14), 4.03 d (1H, 14), 7.2
7.36 m (5H)
(c = 10, Et2O)
0.32 0.46 m (2H), 0.70 0.90 m (2H), 75.94
0.96 t (3H, 7.5), 1.46 1.86 m
(2H), 1.98 d.d (1H, 8, 6), 3.80 d
(2H, 14) 4.00 d (2H, 14), 7.20
7.40 m (5H)
9.25
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 9 2001

1242
LYSENKO, KULINKOVICH
Table 2. (Contd.)
Found, %
Calculated, %
Comp. Yield,
[ ]1D7, deg
1H NMR spectrum, , ppm (J, Hz)
Formula
no.
%
C
H
C
H
IVf
93
0.26 0.38 m (1H), 0.38 0. 50 m 75.12
(1H), 0. 70 0.82 m (2H), 1.10 d
(3H, 6. 5), 2.28 q (1H, 6.5), 2.40
3.00 s (2H), 3.82 d (2H, 13),
3.90 d (2H, 13), 7.20 7.40 m (5H)
9.05
C12H17NO 75.35
8.96
IVg
90
0.34 0.58 m (2H), 0.66 0.78 m (1H), 76.82
0.86 1.00 m (1H), 1.04 d (3H, 7),
1.06 d (3H, 7), 1.84 d (1H, 7),
1.98 m (1H), 2.40 br.s (2H),
3.78 d (1H, 13), 4.08 d (1H, 13),
7.20 7.40 m (5H)
9.58
C14H21NO 76.67
9.65
a
mp 54 56 C (from hexane ether).
mp 47 48 C (from hexane ether).
b
pipecolic acid ethyl ester (Ii) [13] were synthesized by
known methods.
sulfate, and the solvent was distilled off. The yields,
spectral parameters, and elemental analyses of 1-(1-di-
benzylaminoalkyl)-1-cyclopropanols IIa IIg are given
in Table 1.
1-(1-Dibenzylaminoalkyl)-1-cyclopropanols
IIa IIg. To a solution of 5 mmol of ester Ia Ig and
0.28 ml (1 mmol) of titanium tetraisopropoxide in
15 ml of diethyl ether we added with stirring at room
temperature 15 ml of a 1 M solution of ethylmagne-
sium bromide (over a period of 40 60 min). The
mixture was left overnight, cooled to 0 C, treated
with 12 ml of 2 M hydrochloric acid, and stirred for
2 4 h at room temperature. When oily amino alcohol
hydrochlorides (compounds IIb and IIf) separated
from the mixture, the layers were allowed to settle
down, and the ether layer was decanted. The oily
material was dissolved in 10 ml of methylene
chloride, and the aqueous phase was additionally
treated with 2 10 ml of methylene chloride. The
methylene chloride extracts containing crude hydro-
chlorides of IIb and IIf were combined, washed
with 5 ml of a saturated aqueous solution of sodium
chloride and 5 ml of a saturated aqueous solution of
sodium hydrogen carbonate and dried over anhy-
drous sodium sulfate. Removal of the solvent under
reduced pressure gave aminoalkylcyclopropanols IIb
and IIf. Oily hydrochlorides of amino alcohols IIa,
IIc IIe, and IIg crystallized; the precipitate was
filtered off, washed on a filter with 5 ml of 1 M hy-
drochloric acid and 5 ml of diethyl ether, and dried
in air. The solid hydrochlorides were treated with 5 ml
of aqueous sodium hydrogen carbonate, free bases
IIa, IIc IIe, and IIg were extracted into methylene
chloride, the extract was dried over anhydrous sodium
1-(1-Benzyltetrahydro-1H-2-pyrrolyl)-1-cyclo-
propanol (IIh) and 1-(1-benzyl-2-piperidinyl)-1-
cyclopropanol (IIi). A solution of 5 mmol of N-ben-
zyl amino acid ester Ih or Ii and 0.35 ml (1.25 mmol)
of titanium tetraisopropoxide in 15 ml of tetrahydro-
furan was heated to the boiling point, and 20 ml of
a 1 M solution of ethylmagnesium bromide in tetra-
hydrofuran was added with stirring over a period of
40 60 min. The mixture was refluxed for an addi-
tional 1 h while stirring. The solvent was distilled off
under reduced pressure, and the residue was treated
with 18 ml of 2 M hydrochloric acid on cooling to
0 C. The mixture was stirred for 2 h, the organic
phase was separated, and the aqueous layer was
saturated with solid sodium chloride and extracted
with methylene chloride (3 10 ml). The combined
organic extracts were washed with 5 ml of a saturated
solution of sodium hydrogen carbonate, dried over
magnesium sulfate, and evaporated. The residue was
subjected to column chromatography on silica gel
using benzene diethyl ether as eluent. The yields,
spectral parameters, and elemental analyses of com-
pounds IIh and IIi are given in Table 1.
1-(1-Aminoalkyl)-1-cyclopropanols IIIa IIIe
were obtained by hydrogenation of 5 20 mmol of
1-(1-dibenzylaminoalkyl)-1-cyclopropanols IIa IIe
in the presence of Pd(OH)2/C, following the procedure
described in [10]. Products IIIa IIIe were quickly
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 9 2001

A CONVENIENT PROCEDURE FOR PREPARATION OF 1-(1-AMINOALKYL)-. . .
1243
distilled under reduced pressure (oil pump). The
yields, spectral parameters, and elemental analyses
of aminoalkylcyclopropanols IIIa IIIe are sum-
marized in Table 2.
5. Salaun, J., Bennani, F., Compain, J.-C., Fadel, A.,
and Ollivier, J., J. Org. Chem., 1980, vol. 45, no. 21,
pp. 4129 4135; Perelygina, O.P., Zaitseva, G.S., and
Baukov, Yu.I., Zh. Obshch. Khim., 1984, vol. 54,
no. 11, pp. 2643 2644.
1-(1-Benzylaminoalkyl)-1-cyclopropanols IVa
IVg. Methanol, 10 100 ml, was added to 5 50 mmol
of crude hydrochloride of IIa IIg, obtained after
removal of the solvent from the methylene chloride
extract (see above). The catalyst (20% of palladium
hydroxide on charcoal, 10 wt % of the initial hydro-
chloride) was added, and the mixture was stirred
under hydrogen (atmospheric pressure). When hydro-
gen was no longer absorbed, the catalyst was filtered
off and washed with methanol on a filter. The filtrate
was evaporated, and the residue was neutralized with
aqueous ammonia and extracted with ether. The
extract was dried over anhydrous sodium sulfate and
evaporated to leave products IVb IVg as yellowish
oily substances which turned dark on storage; amino
alcohol IVa was isolated as a low-melting crystalline
substance. Table 2 lists the yields, spectral parameters,
and elemental analyses of 1-(1-benzylaminoalkyl)-1-
cyclopropanols IVa IVg.
6. Kulinkovich, O.G., Sviridov, S.V., Vasilevskii, D.A.,
and Pritytskaya, T.S., Zh. Org. Khim., 1989, vol. 25,
no. 10, pp. 2244 2245; Kulinkovich, O.G., Sviri-
dov, S.V., and Vasilevskii, D.A., Synthesis, 1991,
no. 3, pp. 234 235.
7. Achmatowicz, V., Jankowski, P., and Wicha, J.,
Tetrahedron Lett., 1996, vol. 37, no. 31, pp. 5589
5592; Raiman, M.V., Il’ina, N.A., and Kulinko-
vich, O.G., Synlett., 1999, no. 7, pp. 1053 1054.
8. Kulinkovich, O.G., Sviridov, S.V., Vasilevskii, D.A.,
and Savchenko, A.I., Zh. Org. Khim., 1991, vol. 27,
no. 7, pp. 1431 1432; Kulinkovich, O.G., Sviri-
dov, S.V., and Vasilevskii, D.A., Zh. Org. Khim.,
1991, vol. 27, no. 12, p. 2132; Kulinkovich, O.G.,
Masalov, N.V., Tyvorskii, V.I., de Kimpe, N., and
Keppens, M., Tetrahedron Lett., 1996, vol. 37, no. 7,
pp. 1095 1096.
9. Okamoto, S., Iwakubo, M., Kobayashi, K., and
Sato, F., J. Am. Chem. Soc., 1997, vol. 119, no. 30,
pp. 6984 6990; Shirai, M., Okamoto, S., and
Sato, F., Tetrahedron Lett., 1999, vol. 40, pp. 5331
5332.
REFERENCES
1. Verlinde, C.L., Blaton, N.M., de Ranter, C.J., and
Peeters, O.M., Acta Crystallorg., Sec. C, 1984,
vol. 40, pp. 1759 1761.
10. Yoshida, K., Nakajima, Sh., Wakamatsu, T., Ban, Y.,
and Shibasaki, M., Heterocycles, 1988, vol. 27,
no. 5, pp. 1167 1168.
2. Fuller, R.W. and Leander, J.D., J. Pharm. Pharmacol.,
11. Barluenga, J., Baragana, B., and Concellon, J.M.,
1984, vol. 36, no. 5, pp. 345 346.
J. Org. Chem., 1995, vol. 60, no. 21, pp. 6696 6699.
3. Dappen, M.S., Pellicciari, R., Natalini, V., Mona-
han, J.V., Chiarri, C., and Cordi, A.A., J. Med. Chem.,
1991, vol. 34, p. 161.
12. Moragues, J., Prieto, J., and Spickett, R.G.W.,
J. Chem. Soc., Perkin Trans. 1, 1976, no. 9, p. 939.
4. Rahtz, D., Pascheike, G., and Schroeder, E., Eur.
J. Med. Chem., 1977, vol. 12, no. 6, pp. 487 494.
13. Hill, A.J. and Shepard, R.A., J. Org. Chem., 1954,
vol. 19, no. 11, pp. 1802 1806.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 9 2001