Novel modified chiral NiII complexes with the Schiff bases of (E)- and (Z)-2-aminobut-2-enoic acids: Synthesis and study

Article abstract of DOI:10.1007/s11172-006-0276-1

Ni^II complexes with the Schiff bases of (E)-and (Z)-2-aminobut-2-enoic acids were obtained with (S)-N-(2-benzoylphenyl)-1-(2- chlorobenzyl)pyrrolidine-2-carboxamide and (S)-N-(2-benzoylphenyl)-1-(3,4- dimethylbenzyl)pyrrolidine-2-carboxamide as

Full text of DOI:10.1007/s11172-006-0276-1

Russian Chemical Bulletin, International Edition, Vol. 55, No. 3, pp. 442—450, March, 2006
442
Novel modified chiral NiII complexes
with the Schiff bases of (E )ꢀ and (Z )ꢀ2ꢀaminobutꢀ2ꢀenoic acids:
synthesis and study
a
a
a
a
A. S. Saghiyan,a L. L. Manasyan, S. A. Dadayan, S. G. Petrosyan, A. A. Petrosyan,

V. I. Maleev,b and V. N. Khrustalev
b

aDepartment of Chemistry, Yerevan State University,
1 ul. A. Manukyana, 375049 Yerevan, Republic of Armenia.
Fax: +7 (374 1) 54 4183. Eꢀmail: sagysu@netsys.am
bA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Eꢀmail: vim@ineos.ac.ru
NiII complexes with the Schiff bases of (E )ꢀ and (Z )ꢀ2ꢀaminobutꢀ2ꢀenoic acids were
obtained with (S)ꢀNꢀ(2ꢀbenzoylphenyl)ꢀ1ꢀ(2ꢀchlorobenzyl)pyrrolidineꢀ2ꢀcarboxamide and
(S)ꢀNꢀ(2ꢀbenzoylphenyl)ꢀ1ꢀ(3,4ꢀdimethylbenzyl)pyrrolidineꢀ2ꢀcarboxamide as new chiral
auxiliaries. Asymmetric addition of nucleophiles to the C=C bond of these complexes was
studied.
Key words: 2ꢀaminobutꢀ2ꢀenoic acid, asymmetric synthesis, diastereoselectivity, stereoꢀ
isomers.
Many physiologically active peptides, antibiotics, and
observed with complexes with another chiral reagent,
various pharmaceutical drugs contain enantiomerically
pure nonꢀproteinogenic amino acids,1—4 including βꢀsubꢀ
stituted derivatives of αꢀaminobutyric acid.5,6 In addiꢀ
tion, isotopeꢀlabelled amino acids are of considerable curꢀ
rent interest: they are successfully used in positron emisꢀ
sion tomography for early diagnostics of cancer diseases.7
For this reason, a search for novel chiral auxiliaries and
catalysts that ensure highly selective and rapid asymmetꢀ
ric synthesis of amino acids remains of topical interest.8—10
Sufficiently well known studies on asymmetric synꢀ
thesis of αꢀ and βꢀsubstituted αꢀamino acids are based
on increased reactivities of amino acid and dehydroꢀ
amino acid fragments in square planar NiII complexes
with Schiff bases with the chiral auxiliary reagent
(S)ꢀNꢀ(2ꢀbenzoylphenyl)ꢀ1ꢀbenzylpyrrolidineꢀ2ꢀcarboxꢀ
amide ((S)ꢀBPB).11—15
Earlier, to enhance the enantioselectivity by increasꢀ
ing the steric strain in complexes, their structures have
been modified via replacement of the benzyl group in the
chiral reagent by naphthylmethyl,16 2,4,6ꢀtrimethylꢀ
benzyl,17 and 3,4ꢀdichlorobenzyl groups.18 The enantioꢀ
selectivity has increased when passing from benzylproline
derivatives to naphthylmethylproline ones;16 however,
these reagents have found no use. In the case of 2,4,6ꢀtriꢀ
methylbenzylproline complexes, the stereoselectivity of
the synthesis of amino acids has been low (41—66%).17
The high reaction stereoselectivity and rate have been
namely, (S)ꢀNꢀ(2ꢀbenzoylphenyl)ꢀ1ꢀ(3,4ꢀdichlorobenꢀ
zyl)pyrrolidineꢀ2ꢀcarboxamide ((S)ꢀ3,4ꢀDCBPB) (ee of
the resulting amino acids were 90—99%).18—20
Previous19,20 studies of NiII complexes with the Schiff
bases of (E )ꢀ and (Z )ꢀ2ꢀaminobutꢀ2ꢀenoic acids in asymꢀ
metric addition reactions with nucleophiles (alcohols,
thiols, and amines) in the presence of the chiral auxiliary
reagents (S)ꢀBPB and (S)ꢀ3,4ꢀDCBPB have given birth
to methods for the asymmetric synthesis of βꢀsubstiꢀ
tuted αꢀaminobutyric acids of the absolute configuration
((S)ꢀanti (or Lꢀallo)).
Thus, introduction of electronꢀwithdrawing Cl atoms
into the aromatic ring of the Nꢀbenzylproline residue inꢀ
creases the diastereoselectivity and rate of nucleophilic
addition. However, this is the only example; because of
the foregoing demand for a rapid and highly stereoselective
route to amino acids, it was expedient to check this trend.
Results and Discussion
Here we present the synthesis from proline derivatives
1a,b of the novel chiral auxiliaries (S)ꢀNꢀ(2ꢀbenzoylꢀ
phenyl)ꢀ1ꢀ(2ꢀchlorobenzyl)pyrrolidineꢀ2ꢀcarboxamide
(2a) and (S)ꢀNꢀ(2ꢀbenzoylphenyl)ꢀ1ꢀ(3,4ꢀdimethylbenꢀ
zyl)pyrrolidineꢀ2ꢀcarboxamide (2b), as well as of NiII
complexes with their Schiff bases with the amino acids
glycine, alanine, and threonine (3a,b—6a,b) and (E )ꢀ and
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 428—435, March, 2006.
1066ꢀ5285/06/5503ꢀ0442 © 2006 Springer Science+Business Media, Inc.

Chiral Ni complexes with 2ꢀaminobutenoic acid
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
443
Scheme 1
Ar = 2ꢀClC6H4 (a), 3,4ꢀMe2C6H3 (b)
(Z )ꢀ2ꢀaminobutꢀ2ꢀenoic acids (7a,b) (Scheme 1). Comꢀ
plexes 7a,b were studied in reactions with nucleophiles
(asymmetric addition to the C=C bond).
(S)ꢀalanineꢀcontaining complex is dominant). In the case
of the threonine complexes, the de value was 96.5% (5a)
and 91% (5b), the diastereomer containing (R)ꢀthreonine
being major.
The configurations of complexes 4a,b were determined
by Xꢀray diffraction analysis. The molecular structures of
complexes 4a,b are shown in Fig. 1. The Xꢀray diffraction
data unambiguously confirm the (S)ꢀconfiguration of the
alanine residue.
Novel chiral auxiliaries and their NiII complexes of
Schiff bases with amino acids were synthesized as deꢀ
scribed earlier18,19,21,22 (see Scheme 1). The thermodyꢀ
namic stereoselectivities of formation of complexes of
(S)ꢀalanine 4a,b* and (R)ꢀthreonine 5a,b were determined
by chiral GLC analysis of a mixture of amino acids isoꢀ
lated upon decomposition of the equilibrium mixture of
the diastereomeric complexes. The stereoselectivity was
96% for complex 4a and 92.5% for complex 4b (the
The ratio of the (E )ꢀ to (Z )ꢀisomers obtained in the
1
synthesis of complexes 7a,b was determined by H NMR
spectroscopy from the relative intensities of the signals for
the Me protons in the dehydroaminobutyric fragment:
the ratio was 2 : 1 and 3 : 1 for 7a and 7b, respectively.
These (E )/(Z ) values are lower than those for complexes
based on the chiral reagent (S)ꢀBPB.19 Such a phenomꢀ
enon has been noted in the preparation of complexes of
2ꢀaminobutꢀ2ꢀenoic acid with (S)ꢀ3,4ꢀDCBPB.20
* For the synthesis of the complexes, racemic alanine was used
in a double excess with respect to the chiral reagent. As shown
earlier,12,13,20 the stereoselectivity of the process does not deꢀ
pend on whether racemic or optically pure (S)ꢀ or (R)ꢀalanine
is used.

444
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
Saghiyan et al.
oped procedure19,20 (Scheme 2). For this purpose, both
the pure (E )ꢀ and (Z )ꢀisomers of complexes 7a,b and
their synthetic mixture were used. In all cases, the addiꢀ
tion gave a mixture of diastereomeric complexes with a
large excess of the (S,S,S)ꢀdiastereomer. The major
diastereomeric complexes 8a,b and 9a,b were isolated by
column chromatography and characterized by spectroꢀ
scopic methods.
N(1)
C(4)
Scheme 2
C(6)
H(1)
C(5)
4a
Ar
R
Ar
R
8a
8b
2ꢀClC6H4
3,4ꢀMe2C6H3 Me
Me
9a
9b
2ꢀClC6H4
3,4ꢀMe2C6H3 Et
Et
The configuration of the αꢀC atom of the amino acid
residue was determined from the sign of the optical rotaꢀ
tion at a wavelength of 589 nm, as had been done earꢀ
lier19,20 for complexes of these amino acids with the chiral
reagents (S)ꢀBPB and (S)ꢀ3,4ꢀDCBPB.
N(1)
C(4)
C(6)
H(1)
The configuration of the βꢀC atom of the amino acid
C(5)
1
residue was determined by H NMR spectroscopy. Earꢀ
lier, it has been shown that in the spectra of antiꢀisomers
((S,S,S)ꢀdiastereomers), the signals for the βꢀMe protons
of the amino acid residue appear in the higher fields
than the relatively lowꢀfield signals for the synꢀisomers
((S,S,R)ꢀdiastereomers).19,20 The data obtained suggest
that the major adducts are complexes 8a,b and 9a,b with
the (S,S,S)ꢀconfiguration. According to the sign of the
optical rotation and 1H NMR data, the sole accompanyꢀ
ing minor diastereomer in the case of complexes 8a and 9a
is the complex with (S,S,R)ꢀconfiguration. In the case of
complexes 8b and 9b, no accompanying minor diastereoꢀ
mers* were isolated in the individual state.
4b
Fig. 1. Structures 4a,b according to the Xꢀray diffraction data.
The (E )ꢀ and (Z )ꢀconfigurations of isomers 7a,b were
assigned from 1H NMR data for the individual complexes
by analogy with the (S)ꢀBPBꢀbased complex.19 The specꢀ
tra of the isomers with the higher Rf values show relatively
lowꢀfield signals (δ 1.62 and 1.64 for 7a and 7b, respecꢀ
tively), which is characteristic of the (E )ꢀconfiguration.19
Analogous signals for the isomers with the lower Rf values
appear in higher fields (δ 0.88 and 0.92 for 7a and 7b,
respectively). This indicates considerable shielding of the
Me protons due to the magnetic anisotropy of the phenyl
substituent at the C=N bond, which is characteristic of the
(Z )ꢀconfiguration of the dehydroaminobutyric fragment.
Addition of alkoxide ions to the C=C bond of comꢀ
plexes 7a,b was carried out according to an earlier develꢀ
The (S,S,S)/(S,S,R) ratio for complexes 8a,b and 9a,b
was determined from the integral intensity ratio of the
signals for the βꢀMe group of the amino acid residue
1
when analyzing the H NMR spectra of a mixture of the
diastereomers (Table 1). In addition, the ratio of the amino
acid diastereomers determined for complexes 8a,b by
* In this case, two accompanying diastereomeric complexes
were detected (1H NMR data).

Chiral Ni complexes with 2ꢀaminobutenoic acid
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
445
Table 1. Addition of alkoxide ions to complexes (E )ꢀ7a,b and
(Z )ꢀ7a,b at 55—60 °C
reached with complexes based on the modified chiral reꢀ
agent 2a. This can be explained by analyzing the strucꢀ
tures of complexes 4a,b (see Fig. 1)*. According to Xꢀray
diffraction data, the presence of substituents in the aroꢀ
matic ring of the Nꢀbenzylproline fragment causes its benꢀ
zyl group to change position above the nickel coordinaꢀ
tion plane. In structure 4a, the electronꢀwithdrawing subꢀ
stituent of the benzylproline residue is directly above the
NiII ion and its apical coordination to the nickel ion
seems to be quite probable. This substantially changes the
electron density distribution in the complex and we asꢀ
sume that the increase in the reaction rate can be mainly
associated with such a coordination. In addition, because
the 2ꢀchlorobenzyl fragment comes closer to the nickel
ion (Ni...Cl 3.149 Å), the angle between the Ph group of
the benzophenone residue and the nickel coordination
plane in the complexes changes (the deviation of the diꢀ
hedral N(1)—C(4)—C(5)—C(6) angle from 90°, see
Fig. 1). This angle for complexes of the type 4 based on
the chiral reagents (S)ꢀ3,4ꢀDCBPB, 2b, and 2a was 6°,
8°, and 20°, respectively. With an increase in this angle,
steric interactions between the Ph group at the azomethine
bond and the αꢀH(1) atom of the (S)ꢀamino acid fragꢀ
ment become stronger; as the result, the (S)ꢀamino acid
chelate ring is distorted and the H(1) atom occupies
an unfavorable equatorial position. In the case of the
complexes of (R)ꢀamino acid, the Ph group at the
azomethine bond interacts with the bulky alkyl radical
rather than the Hα atom, which makes the system more
strained. Thus, the complex of the (R)ꢀamino acid should
become substantially less favorable in the order (S)ꢀBPB,
(S)ꢀ3,4ꢀDCBPB, 2b, and 2a, while this effect for comꢀ
plexes of the (S)ꢀamino acid is not so pronounced. Thereꢀ
fore, the energy difference between the diastereomeric
complexes with the (S)ꢀ and (R)ꢀamino acids increases,
which means that under thermodynamic control (note
that addition of nucleophiles to the C=C bond of comꢀ
plexes 7a,b is thermodynamically controlled) the content
of the complex with the (R)ꢀamino acid in an equilibrium
diastereomeric mixture will progressively decrease.
Entry
Starting Nucleoꢀ tb/h Proꢀ Yield
dec
complex
philea
duct
(%)
1
2
3
4
5
6
7
8
(E)ꢀ7a
MeO–
MeO–
MeO–
1
4
4
8a
8a
8a
9a
9a
9a
8b
8b
8b
9b
9b
9b
92 >98 (99.5)
(Z )ꢀ7a
(E,Z )ꢀ7ad
(E)ꢀ7a
(Z )ꢀ7a
(E,Z )ꢀ7ad
(E)ꢀ7b
(Z )ꢀ7b
(E,Z )ꢀ7b f
(E)ꢀ7b
(Z )ꢀ7b
(E,Z )ꢀ7b f
88
90
92
88
90
86
83
85
88
85
87
93 (92.5)
96 (96)
>98
95
>98
90 (91e)
80 (71.8e)
85 (85.3e)
89
EtO– 1.5
EtO–
EtO–
MeO–
MeO–
MeO–
EtO–
EtO–
EtO–
20
20
2
3
3
5
2
3
9
10
11
12
56
76
a
0.2 M MeONa in MeOH and 0.04 M EtONa in EtOH
were used.
b The reaction duration.
c The ratio of the diastereomers according to data from 1H NMR
spectroscopy and chiral GLC analysis (in parentheses).
d
The mixture of the (E )ꢀ and (Z )ꢀisomers in the ratio
(E )ꢀ7a/(Z )ꢀ7a = 2 : 1.
e A third diastereomer (<3%) with an unidentified configuration
was detected.
f The mixture of the (E )ꢀ and (Z )ꢀisomers in the ratio
(E )ꢀ7b/(Z )ꢀ7b = 3 : 1.
chiral GLC analysis of their mixture obtained upon deꢀ
composition of the reaction mixture fully agrees with that
1
from the H NMR data. Unfortunately, in the case of
addition of ethanol to complexes 7a,b, we failed to deterꢀ
mine the ratio of the amino acid stereoisomers by chiral
GLC analysis upon the decomposition of the reaction
mixture (complexes 9a,b).
Thus, the addition of the Me– and EtO– ions to the
C=C bond of complexes 7a,b mainly gives complexes
of (2S,3S)ꢀ2ꢀaminoꢀ3ꢀmethoxybutyric acid 8a,b and
(2S,3S)ꢀ2ꢀaminoꢀ3ꢀethoxybutyric acid 9a,b. A compariꢀ
son of our data (see Table 1, entries 1—12) with previous
results (obtained with complexes based on other chiral
derivatives of (S)ꢀproline19,20) reveals increasing de valꢀ
ues in the following order of the chiral auxiliaries: BPB
(de 86%)19 < 3,4ꢀDCBPB (de 90%)20 < 2b (de 91%) < 2a
(de 97%).
The highest de values were obtained in the addition of
alkoxide ions to complex (E )ꢀ7a (see Table 1, entries 1, 4).
In addition, in agreement with previous data,19,20 an inꢀ
crease in de and a reduction in the reaction time of the
nucleophilic addition were observed when passing from
the (Z )ꢀisomers of 2ꢀaminobutꢀ2ꢀenoic acid complexes
to the (E )ꢀisomers (see Table 1; cf. entries 2, 5, 8, and 11
with 1, 4, 7, and 10).
On decomposition of the complexes and isolation of
the amino acids, the starting reagents 2a,b were easily
recovered in >90% yields, their original optical activities
being completely retained.
Thus, we obtained the novel and very promising chiral
reagent 2a, which is suitable for highly stereoselective
asymmetric synthesis of a wide range of amino acids.
Experimental
Commercial reagents were used: amino acids (Reanal,
Hungary); L 40/100 silica gel (Chemapol, Praha); CHCl3, Ac2O,
* Earlier,23 it has been shown that the conformations of the
complexes are identical in the crystal and in solution.
It is evident from the data in Table 1 that the highest
diastereoselectivity and nucleophilic addition rate were

446
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
Saghiyan et al.
AcOH, Me2CO, MeCN, and PriOH (Reakhim); 2ꢀchlorobenzyl
chloride, 3,4ꢀdimethylbenzyl chloride, and 2ꢀaminobenzoꢀ
phenone (Aldrich). All solvents were used freshly distilled. Enanꢀ
tiomeric GLC analysis of amino acids as their isopropyl Nꢀtriꢀ
fluoroacetates was carried out on the ChirasilVal chiral phase24
(capillary quartz column 40 m × 0.23 mm, film thickness
0.12 µm, column temperature 125 °C, helium as a carrier gas).
1H NMR spectra were recorded on a Mercuryꢀ300 Varian inꢀ
strument (300 MHz) in DMSOꢀd6—CCl4 (1 : 3) (unless otherꢀ
wise specified). The signals in the 1H NMR spectra were asꢀ
signed from double resonance and 2D COSY experiments. Optiꢀ
cal rotation was measured on a Perkin—Elmerꢀ341 polarimeter.
Column chromatography was carried out on a glass column
(2×20 cm) packed with L 40/100 silica gel; Merck glass plates
(5×10 cm) were used for TLC.
Complexes 3a,b and 4a,b were obtained according to known
procedures.19,21,22
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
a m i d o ] p h e n y l } { p h e n y l } m e t h y l i d e n e ) g l y c i n a t o ꢀ
N,N´,N″,O]nickel(II) (3a). The yield was 85%, Rf 0.41 (SiO2,
25
CHCl3—acetone (5 : 1)), m.p. 186—188 °C, [α]D +2364
(c 0.05, CHCl3). Found (%): C, 60.85; H, 4.58; N, 7.88.
C27H24ClN3NiO3. Calculated (%): C, 60.88; H, 4.54; N, 7.89.
1H NMR, δ: 2.09—2.19 (m, 2 H, βꢀH Pro, γꢀH Pro); 2.54 (m,
1 H, γꢀH Pro); 2.77 (m, 1 H, βꢀH Pro); 3.43 (m, 1 H, δꢀH Pro);
3
3
3.52 (dd, 1 H, αꢀH Pro, J = 10.9 Hz, J = 6.1 Hz); 3.64 (m,
2
1 H, δꢀH Pro); 3.69, 3.77 (both d, 1 H each, CH2 Gly, J =
20.0 Hz); 4.00, 4.56 (both d, 1 H each, NCH2Ar, 2J = 12.9 Hz);
6.73 (br.t, 1 H, H arom., 3J = 7.6 Hz); 6.83 (dd, 1 H, H arom.,
3J = 8.2 Hz, 4J = 1.8 Hz); 6.98 (br.m, 1 H, H arom.); 7.15 (br.d,
3
3
NꢀBenzylation of proline was carried out as described earꢀ
lier.18 2ꢀChlorobenzyl chloride or 3,4ꢀdimethylbenzyl chloride
was added to the reaction mixture at 0 °C.
1 H, H arom., J = 7.2 Hz); 7.21 (ddd, 1 H, H arom., J =
8.6 Hz, 3J = 6.8 Hz, 4J = 2.0 Hz); 7.27 (dd, 1 H, H arom., 3J =
7.6 Hz, 4J = 1.8 Hz); 7.36 (td, 1 H, H arom., J = 7.5 Hz, 4J =
1.4 Hz); 7.43 (dd, 1 H, H arom., J = 8.1 Hz, J = 1.4 Hz);
7.48—7.56 (m, 3 H, H arom.); 8.18 (dd, 1 H, H arom., J =
3
3
4
(S)ꢀNꢀ(2ꢀChlorobenzyl)proline (1a). The yield was 95%, m.p.
20
20
20
3
160—162 °C, [α]D –21.0, [α]578 –22.1, [α]546 –24.9,
20
20
4
3
[α]436 –40.5, [α]365 –60.4 (c 1.0, EtOH). Found (%):
8.8 Hz, J = 1.0 Hz); 8.29 (dd, 1 H, H arom., J = 7.6 Hz,
4J = 1.8 Hz).
C, 60.35; H, 5.56; N, 5.92. C12H14ClNO2. Calculated (%):
1
C, 60.12; H, 5.85; N, 5.85. H NMR, δ: 1.90—2.14 (m, 3 H,
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
a m i d o ] p h e n y l } { p h e n y l } m e t h y l i d e n e ) g l y c i n a t o ꢀ
N,N´,N″,O]nickel(II) (3b). The yield was 75%, Rf 0.66 (SiO2,
βꢀH Pro, γꢀH Pro); 2.33 (m, 1 H, βꢀH Pro); 2.91 (dt, 1 H,
δꢀH Pro, 2J = 9.8 Hz, 3J = 8.1 Hz); 3.26 (dt, 1 H, δꢀH Pro, 2J =
9.8 Hz, 3J = 6.0 Hz); 3.91 (dd, 1 H, αꢀH Pro, 3J = 8.8 Hz, 3J =
25
CHCl3—acetone (5 : 1)), m.p. 176—178 °C, [α]D +1513
2
6.4 Hz); 4.22, 4.40 (both d, 1 H each, NCH2Ar, J = 13.9 Hz);
(c 0.05, CHCl3). Found (%): C, 66.25; H, 5.44; N, 8.00.
C29H29N3NiO3. Calculated (%): C, 66.20; H, 5.52; N, 7.99.
1H NMR, δ: 2.05—2.24 (m, 2 H, βꢀH Pro); 2.10, 2.18 (both s,
3 H each, Me); 2.36—2.47 (m, 2 H, γꢀH Pro); 3.25—3.41 (m,
2 H, αꢀH Pro, δꢀH Pro); 3.50 (d, 1 H, CH2 Gly, 2J = 20.0 Hz);
3
7.26—7.39 (m, 3 H, H arom.); 7.78 (dd, 1 H, H arom., J =
6.8 Hz, 4J = 2.6 Hz).
(S)ꢀNꢀ(3,4ꢀDimethylbenzyl)proline (1b). The yield was 74%,
20
m.p. 182—185 °C, [α]D –25.6 (c 1.0, EtOH). Found (%):
2
C, 72.10; H, 8.26; N, 6.04. C14H19NO2. Calculated (%):
3.51 (d, 1 H, NCH2Ar, J = 12.3 Hz); 3.57 (m, 1 H, δꢀH Pro);
1
2
C, 72.10; H, 8.15; N, 6.01. H NMR, δ: 1.70—2.15 (m, 4 H,
3.63 (d, 1 H, CH2 Gly, J = 20.0 Hz); 4.32 (d, 1 H, NCH2Ar,
βꢀH Pro, γꢀH Pro); 2.23, 2.24 (both s, 3 H each, Me); 2.40 (m,
2J = 12.9 Hz); 6.60 (ddd, 1 H, H arom., 3J = 8.2 Hz, 3J =
6.8 Hz, 4J = 1.3 Hz); 6.69 (dd, 1 H, H arom., 3J = 8.2 Hz, 4J =
1.8 Hz); 7.05—7.11 (m, 2 H, H arom.); 7.11 (d, 1 H, H arom.,
3J = 7.5 Hz); 7.23 (br.d, 1 H, H arom., 3J = 7.5 Hz); 7.50—7.62
2
3
1 H, δꢀH Pro); 2.95 (ddd, 1 H, δꢀH Pro, J = 9.1 Hz, J =
7.0 Hz, 3J = 4.1 Hz); 3.21 (dd, 1 H, αꢀH Pro, 3J = 8.7 Hz, 3J =
5.6 Hz); 3.45, 3.94 (both d, 1 H each, NCH2Ar, J = 12.8 Hz);
2
3
4
6.99 (s, 2 H, H arom.); 7.05 (s, 1 H, H arom.).
(m, 3 H, H arom.); 7.76 (dd, 1 H, H arom., J = 7.5 Hz, J =
1.9 Hz); 8.13 (dd, 1 H, H arom., 3J = 8.9 Hz, 4J = 1.3 Hz); 8.31
(d, 1 H, H arom., 4J = 1.9 Hz).
Synthesis of chiral amides as hydrochlorides was carried out
as described earlier.18 After all the components were added, the
reaction mixture was stirred at ~20 °C for 15 h.
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(S)ꢀalaninatoꢀ
N,N´,N″,O]nickel(II) (4a). The yield was 92%, Rf 0.64 (SiO2,
(S)ꢀNꢀ(2ꢀBenzoylphenyl)ꢀ1ꢀ(2ꢀchlorobenzyl)pyrrolidineꢀ2ꢀ
carboxamide hydrochloride (2a). The yield was 72%, m.p.
20
25
203—205 °C, [α]D –40.17 (c 1.0, MeOH). Found (%):
CHCl3—acetone (5 : 1)), m.p. 324—326 °C, [α]D +2574
C, 65.91; H, 3.15; N, 6.14. C25H23ClN2O2•HCl.. Calcuꢀ
lated (%): C, 65.93; H, 3.07; N, 6.15. 1H NMR, δ: 1.60 (m, 1 H,
βꢀH Pro); 1.84, 2.03 (both m, 1 H each, γꢀH Pro); 2.43 (m, 1 H,
βꢀH Pro); 4.27—4.90 (br.m, 5 H, αꢀH Pro, δꢀH Pro, NCH2Ar);
(c 0.05, CHCl3). Found (%): C, 61.59; H, 4.81; N, 7.61.
C28H26ClN3NiO3. Calculated (%): C, 61.52; H, 4.76; N, 7.69.
3
1H NMR (CDCl3), δ: 1.58 (d, 3 H, Me Ala, J = 7.0 Hz); 2.09
(m, 1 H, γꢀH Pro); 2.26, 2.64 (both m, 1 H each, βꢀH Pro); 2.94
3
3
3
7.20—7.59 (m, 9 H, H arom.); 7.46 (br.t, 2 H, H arom., J =
(m, 1 H, γꢀH Pro); 3.51 (dd, 1 H, δꢀH Pro, J = 10.4 Hz, J =
3
7.5 Hz); 7.78 (br.d, 2 H, H arom., J = 7.5 Hz); 9.78 (br, 1 H,
6.1 Hz); 3.57 (dd, 1 H, αꢀH Pro, 3J = 11.0 Hz, 3J = 6.1 Hz); 3.72
NH+); 12.15 (br.s, 1 H, HCl).
(m, 1 H, δꢀH Pro); 3.90 (q, 1 H, αꢀH Ala, J = 7.0 Hz); 3.85,
3
(S)ꢀNꢀ(2ꢀBenzoylphenyl)ꢀ1ꢀ(3,4ꢀdimethylbenzyl)pyrrolidineꢀ
2ꢀcarboxamide hydrochloride (2b). The yield was 40%, m.p.
4.50 (both d, 1 H each, NCH2Ar, 2J = 12.9 Hz); 6.64—6.72 (m,
2 H, H arom.); 6.96 (br.d, 1 H, H arom., 3J = 7.3 Hz); 7.25—7.38
(m, 3 H, H arom.); 7.11—7.22 (m, 2 H, H arom.); 7.43—7.54
20
230—235 °C, [α]D –38.46 (c 1.0, MeOH). Found (%):
3
C, 72.10; H, 6.28; N, 6.19. C27H28N2O2•HCl. Calculated (%):
(m, 3 H, H arom.); 8.00 (d, 1 H, H arom., J = 8.6 Hz); 8.22
1
C, 72.24; H, 6.24; N, 6.24. H NMR, δ: 1.76, 2.00 (both m,
(br.d, 1 H, H arom., 3J = 7.5 Hz).
1 H each, βꢀH Pro); 2.21, 2.24 (both s, 3 H each, Me); 3.20—3.38
(m, 2 H, γꢀH Pro); 4.14—4.5 (br.m, 4 H, δꢀH Pro, NCH2Ar);
4.72 (m, 1 H, αꢀH Pro); 7.02—7.56 (m, 10 H, H arom.); 7.77 (d,
(S)ꢀ[({2ꢀ[1ꢀ(3, 4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀ
carboxamido]phenyl}{phenyl}methylidene)ꢀ(S)ꢀalaninatoꢀ
N,N´,N″,O]nickel(II) (4b). The yield was 80%, Rf 0.70 (SiO2,
CHCl3—acetone (5 : 1)), m.p. 315—317 °C (decomp.),
3
2 H, H arom., J = 7.6 Hz); 9.72 (br, 1 H, NH+); 12.11 (br.s,
25
1 H, HCl).
[α]D +2562 (c 0.05, CHCl3). Found (%): C, 66.76; H, 5.79;

Chiral Ni complexes with 2ꢀaminobutenoic acid
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
447
N, 7.71. C30H31N3NiO3. Calculated (%): C, 66.70; H, 5.74;
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(R)ꢀOꢀacetylthreoninatoꢀ
N,N´,N″,O]nickel(II) (6a). The yield was 95%, Rf 0.66 (SiO2,
1
3
N, 7.78. H NMR, δ: 1.50 (d, 3 H, Me Ala, J = 7.1 Hz); 1.90,
2.00 (both s, 3 H each, Me); 2.01 (m, 1 H, γꢀH Pro); 2.17, 2.51
(both m, 1 H each, βꢀH Pro); 2.97 (m, 1 H, γꢀH Pro); 3.21 (d,
25
AcOEt—CHCl3 (3 : 1)), m.p. 120—122 °C, [α]D –448.1
2
3
1 H, NCH2Ar, J = 12.3 Hz); 3.37 (dd, 1 H, αꢀH Pro, J =
(c 0.05, CHCl3). Found (%): C, 60.10; H, 4.78; N, 6.78.
C31H30ClN3NiO5. Calculated (%): C, 60.17; H, 4.85; N, 6.79.
1H NMR, δ: 1.33 (d, 3 H, βꢀMe Thr, 3J = 6.4 Hz); 1.80 (s, 3 H,
Me AcꢀThr); 1.94 (m, 1 H, γꢀH Pro); 2.15 (m, 2 H, βꢀH,
γꢀH Pro); 2.54 (m, 1 H, βꢀH Pro); 2.68 (ddd, 1 H, δꢀH Pro, 2J =
11.3 Hz, 3J = 8.7 Hz, 3J = 6.4 Hz); 3.45 (dd, 1 H, αꢀH Pro, 3J =
9.6 Hz, 3J = 4.4 Hz); 3.61 (d, 1 H, αꢀH Thr, 3J = 7.6 Hz); 4.04
3
11.1 Hz, J = 5.8 Hz); 3.38, 3.63 (both m, 1 H each, δꢀH Pro);
3.74 (q, 1 H, αꢀH Ala, 3J = 7.1 Hz); 4.19 (d, 1 H, NCH2Ar, 2J =
12.3 Hz); 6.49—6.59 (m, 2 H, H arom.); 6.86—7.02 (m, 3 H,
3
4
H arom.); 7.18 (dt, 1 H, H arom., J = 6.8 Hz, J = 2.0 Hz);
3
7.36—7.52 (m, 3 H, H arom.); 7.59 (dd, 1 H, H arom., J =
7.1 Hz, 4J = 1.9 Hz); 7.81 (d, 1 H, H arom., 3J = 8.6 Hz); 8.40
(d, 1 H, H arom., 4J = 1.5 Hz).
2
3
3
(ddd, 1 H, δꢀH Pro, J = 11.3 Hz, J = 6.6 Hz, J = 4.4 Hz);
4.20, 4.83 (both d, 1 H each, NCH2Ar, 2J = 13.8 Hz); 5.34 (dq,
1 H, βꢀH Thr, 3J = 7.6 Hz, 3J = 6.3 Hz); 6.70 (ddd, 1 H,
Aldol condensation of complexes 3a,b was carried out acꢀ
cording to known procedures.19,22 Complexes of (R)ꢀthreonine
were crystallized from heptane—acetone—methanol (1 : 1 : 1).
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(R)ꢀthreoninatoꢀ
N,N´,N″,O]nickel(II) (5a). The yield was 65%, Rf 0.54 (SiO2,
H arom., 3J = 8.3 Hz, 3J = 6.8 Hz, J = 1.2 Hz); 6.81 (dd, 1 H,
4
3
4
H arom., J = 8.3 Hz, J = 1.8 Hz); 7.22 (ddd, 1 H, H arom.,
3J = 8.7 Hz, 3J = 6.9 Hz, 4J = 1.8 Hz); 7.26 (m, 1 H, H arom.);
7.34 (br.d, 1 H, H arom., 3J = 6.8 Hz); 7.42 (ddd, 1 H, H arom.,
3J = 7.9 Hz, J = 7.3 Hz, J = 1.7 Hz); 7.49—7.67 (m, 5 H,
H arom.); 8.47 (dd, 1 H, H arom., J = 8.8 Hz, J = 1.2 Hz);
8.84 (dd, 1 H, H arom., 3J = 7.7 Hz, 4J = 1.7 Hz).
25
3
4
CHCl3—acetone (5 : 1)), m.p. 89—91 °C, [α]D –679.3
3
4
(c 0.05, CHCl3). Found (%): C, 60.60; H, 4.78; N, 7.21.
C29H28ClN3NiO4. Calculated (%): C, 60.40; H, 4.85; N, 7.28.
1H NMR, δ: 1.13 (d, 3 H, βꢀMe Thr, 3J = 6.2 Hz); 1.93 (m, 1 H,
βꢀH Pro); 2.05—2.23 (m, 2 H, βꢀH Pro, γꢀH Pro); 2.48 (m, 1 H,
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(R)ꢀOꢀacetylthreoninatoꢀ
N,N´,N″,O]nickel(II) (6b). The yield was 80%, Rf 0.92 (SiO2,
2
3
γꢀH Pro); 2.74 (ddd, 1 H, δꢀH Pro, J = 11.5 Hz, J = 8.5 Hz,
3J = 6.4 Hz); 3.42 (d, 1 H, αꢀH Thr, 3J = 7.2 Hz); 3.47 (dd, 1 H,
αꢀH Pro, 3J = 9.1 Hz, 3J = 4.6 Hz); 4.06 (d, 1 H, NCH2Ar, 2J =
14.1 Hz); 4.10—4.21 (m, 2 H, δꢀH Pro, βꢀH Thr); 4.67 (d, 1 H,
25
AcOEt—CHCl3 (3 : 1)), m.p. 193—195 °C, [α]D –1092.5
(c 0.05, CHCl3). Found (%): C, 64.98; H, 5.64; N, 6.92.
C33H35N3NiO5. Calculated (%): C, 64.73; H, 5.72; N, 6.86.
1H NMR, δ: 1.40 (d, 3 H, βꢀMe Thr, 3J = 6.4 Hz); 1.81 (s, 3 H,
Me AcꢀThr); 2.07 (m, 2 H, βꢀH Pro, γꢀH Pro); 2.30, 2.32
(both s, 3 H each, Me); 2.40 (m, 1 H, γꢀH Pro); 2.64 (m, 1 H,
2
3
NCH2Ar, J = 14.1 Hz); 5.14 (d, 1 H, OH, J = 6.4 Hz); 6.68
(ddd, 1 H, H arom., 3J = 8.3 Hz, 3J = 6.9 Hz, 4J = 1.3 Hz); 6.78
3
4
(dd, 1 H, H arom., J = 8.3 Hz, J = 1.8 Hz); 7.19 (ddd, 1 H,
3
3
4
3
3
H arom., J = 8.8 Hz, J = 6.9 Hz, J = 1.8 Hz); 7.27, 7.33
(both m, 1 H each, H arom.); 7.41—7.64 (m, 6 H, H arom.);
8.52 (dd, 1 H, H arom., 3J = 8.8 Hz, 4J = 1.0 Hz); 9.25 (dd, 1 H,
H arom., 3J = 7.7 Hz, 4J = 1.6 Hz).
βꢀH Pro); 3.55 (dd, 1 H, αꢀH Pro, J = 9.5 Hz, J = 4.0 Hz);
3.63 (d, 1 H, αꢀH Thr, 3J = 7.4 Hz); 3.84 (d, 1 H, NCH2Ar, 2J =
2
3
13.2 Hz); 3.92 (ddd, 1 H, δꢀH Pro, J = 11.5 Hz, J = 7.3 Hz,
3J = 4.2 Hz); 4.13 (dd, 1 H, δꢀH Pro, 3J = 5.8 Hz, 3J = 3.6 Hz);
2
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(R)ꢀthreoninatoꢀ
N,N´,N″,O]nickel(II) (5b). The yield was 47%, Rf 0.81 (SiO2,
4.73 (d, 1 H, NCH2Ar, J = 13.2 Hz); 5.37 (dq, 1 H, βꢀH Thr,
3J = 7.4 Hz, 3J = 6.4 Hz); 6.68 (ddd, 1 H, H arom., 3J = 8.4 Hz,
3J = 6.7 Hz, 4J = 1.1 Hz); 6.77 (dd, 1 H, H arom., 3J = 8.2 Hz,
4J = 1.9 Hz); 7.18—7.24 (m, 3 H, H arom.); 7.32 (br.d, 1 H,
25
CHCl3—acetone (5 : 1)), m.p. 165—167 °C, [α]D –1104.0
3
4
(c 0.05, CHCl3). Found (%): C, 65.60; H, 5.85; N, 8.00.
C31H33N3NiO4. Calculated (%): C, 65.30; H, 5.91; N, 7.89.
1H NMR, δ: 1.20 (d, 3 H, βꢀMe Thr, 3J = 6.2 Hz); 1.86 (m, 1 H,
βꢀH Pro); 1.97—2.15 (m, 2 H, βꢀH Pro, γꢀH Pro); 2.41 (m, 1 H,
γꢀH Pro); 2.32, 2.34 (both s, 3 H each, Me); 2.68 (m, 1 H,
H arom., J = 7.1 Hz); 7.42 (d, 1 H, H arom., J = 1.9 Hz);
7.50—7.59 (m, 3 H, H arom.); 7.66 (m, 1 H, H arom.); 8.50 (dd,
1 H, H arom., 3J = 8.8 Hz, 4J = 1.0 Hz).
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(E )ꢀ2ꢀaminobutꢀ2ꢀenoatoꢀ
N,N´,N″,O]nickel(II) ((E )ꢀ7a). The yield was 67.4%, Rf 0.55
3
δꢀH Pro); 3.42 (d, 1 H, αꢀH Thr, J = 7.2 Hz); 3.55 (dd, 1 H,
δꢀH Pro, 3J = 9.1 Hz, 3J = 4.0 Hz); 3.63 (d, 1 H, NCH2Ar, 2J =
(SiO2, AcOEt—CHCl3 (3 : 1)), m.p. 218—220 °C,
3
3
13.0 Hz); 4.15 (ddq, 1 H, βꢀH Thr, J = 7.2 Hz, J = 6.4 Hz,
3J = 6.2 Hz); 4.26 (m, 1 H, αꢀH Pro); 4.49 (d, 1 H, NCH2Ar,
2J = 13.0 Hz); 5.05 (d, 1 H, OH); 6.66 (br.t, 1 H, H arom., 3J =
7.5 Hz); 6.74 (dd, 1 H, H arom., 3J = 8.3 Hz, 4J = 1.8 Hz); 7.16
[α]D25 +3031.8 (c 0.022, CHCl3). Found (%): C, 62.42; H, 4.75;
N, 7.45. C29H26ClN3NiO3. Calculated (%): C, 62.34; H, 4.65;
N, 7.52. 1H NMR, δ: 1.62 (d, 3 H, >C=CH(Me), 3J = 7.4 Hz);
2.14—2.31 (m, 2 H, βꢀH Pro, γꢀH Pro); 2.60 (m, 1 H, γꢀH Pro);
3
3
4
3
(ddd, 1 H, H arom., J = 8.7 Hz, J = 6.8 Hz, J = 1.8 Hz);
7.21—7.32, 7.46—7.53 (both m, 3 H each, H arom.); 7.60 (m,
1 H, H arom.); 7.75 (dd, 1 H, H arom., 3J = 7.7 Hz, 4J =
1.8 Hz); 8.51 (d, 1 H, H arom., 3J = 8.7 Hz).
2.78 (m, 1 H, βꢀH Pro); 3.28 (dd, 1 H, δꢀH Pro, J = 9.1 Hz,
3J = 6.2 Hz); 3.55 (dd, 1 H, αꢀH Pro, 3J = 11.0 Hz, 3J = 6.2 Hz);
3.67 (m, 1 H, δꢀH Pro); 3.78, 4.22 (both d, 1 H each, NCH2Ar,
3
2J = 12.6 Hz); 5.05 (q, 1 H, >C=CH(Me), J = 7.4 Hz); 6.65
OꢀAcetylation and deacetylation of complexes 5a,b were carꢀ
ried out as described earlier.19,20 After the deacetylation was
completed, the reaction mixture was diluted with a fivefold exꢀ
cess of water and the precipitate of 2ꢀaminobutꢀ2ꢀenoic acid
complexes that formed was filtered off. The product was obꢀ
tained as a mixture of the (E )ꢀ and (Z )ꢀisomers of complexes
7a,b, which were separated by column chromatography on silica
gel with AcOEt—CHCl3 (3 : 1) as an eluent.
(ddd, 1 H, H arom., 3J = 8.3 Hz, 3J = 6.8 Hz, 4J = 1.3 Hz); 6.82
3
4
(dd, 1 H, H arom., J = 8.3 Hz, J = 1.8 Hz); 7.04 (ddd, 1 H,
H arom., 3J = 8.7 Hz, 3J = 6.9 Hz, 4J = 1.8 Hz); 7.12—7.38 (m,
5 H, H arom.); 7.46 (m, 3 H, H arom.); 7.98 (dd, 1 H, H arom.,
3
3J = 8.7 Hz, 4J = 1.1 Hz); 8.21 (dd, 1 H, H arom., J = 7.7 Hz,
4J = 1.8 Hz).
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(Z )ꢀ2ꢀaminobutꢀ2ꢀenoatoꢀ

448
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
Saghiyan et al.
25
N,N´,N″,O]nickel(II) ((Z )ꢀ7a). The yield was 32.6%, Rf 0.44
(SiO2, AcOEt—CHCl3 (3
188—190 °C, [α]D +2935 (c 0.05, CHCl3). Found (%):
C, 61.15; H, 5.22; N, 7.08. C30H30ClN3NiO4. Calculated (%):
C, 61.00; H, 5.12; N, 7.11. 1H NMR, δ: 1.05 (d, 3 H,
:
1)), m.p. 243—244 °C,
[α]D25 +2645.0 (c 0.02, CHCl3). Found (%): C, 62.38; H, 4.75;
N, 7.58. C29H26ClN3NiO3. Calculated (%): C, 62.34; H, 4.65;
N, 7.52. 1H NMR, δ: 0.88 (d, 3 H, >C=CH(Me), 3J = 7.6 Hz);
2.18 (m, 1 H, βꢀH Pro); 2.29, 2.64 (both m, 1 H each, γꢀH Pro);
3
>CH—CH(Me), J = 6.4 Hz); 2.05—2.21 (m, 2 H, γꢀH Pro);
2.60, 2.84 (both m, 1 H each, βꢀH Pro); 3.26 (m, 1 H, δꢀH Pro);
3.29 (qd, 1 H, >CH—CH(Me), 3J = 6.4 Hz, 3J = 2.2 Hz);
3
3
3
3.24 (m, 1 H, βꢀH Pro); 3.56 (dd, 1 H, αꢀH Pro, J = 10.9 Hz,
3.46 (dd, 1 H, αꢀH Pro, J = 10.7 Hz, J = 6.7 Hz); 3.56 (s,
3 H, OMe); 3.57 (d, 1 H, >CH—CH(Me), J = 2.2 Hz); 3.81
3J = 6.2 Hz); 3.73 (d, 1 H, NCH2Ar, 2J = 12.6 Hz); 3.75
(m, 1 H, δꢀH Pro); 4.13 (d, 1 H, NCH2Ar, 2J = 12.6 Hz);
3
(m, 1 H, δꢀH Pro); 3.87, 4.29 (both d, 1 H each, NCH2Ar,
3
3
4.13 (dd, 1 H, δꢀH Pro, J = 5.6 Hz, J = 3.5 Hz); 5.55 (q,
2J = 12.7 Hz); 6.59—6.62, 7.01—7.12 (both m, 2 H each,
3
3
4
1 H, >C=CH(Me), J = 7.6 Hz); 6.69 (ddd, 1 H, H arom.,
H arom.); 7.17 (td, 1 H, H arom., J = 7.7 Hz, J = 1.7 Hz);
7.29—7.39, 7.45—7.68 (both m, 3 H each, H arom.); 8.05 (d,
1 H, H arom., 3J = 8.6 Hz); 8.26 (dd, 1 H, H arom., 3J = 7.7 Hz,
4J = 1.6 Hz).
3J = 8.2 Hz, 3J = 6.8 Hz, 4J = 1.0 Hz); 6.98 (dd, 1 H, H arom.,
3J = 8.2 Hz, 4J = 1.8 Hz); 7.2 (ddd, 1 H, H arom., 3J =
8.6 Hz, 3J = 6.8 Hz, 4J = 1.8 Hz); 7.22—7.42 (m, 5 H,
H arom.); 7.56 (m, 3 H, H arom.); 7.98 (dd, 1 H, H arom., 3J =
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(2S,3S)ꢀOꢀmethylthreoꢀ
ninatoꢀN,N´,N″,O]nickel(II) (8b). The yield was 85%, m.p.
4
3
8.6 Hz, J = 1.1 Hz); 8.19 (dd, 1 H, H arom., J = 7.7 Hz,
4J = 1.8 Hz).
25
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(E )ꢀ2ꢀaminobutꢀ2ꢀenoatoꢀ
N,N´,N″,O]nickel(II) ((E )ꢀ7b). The yield was 60%, Rf 0.82 (SiO2,
220—222 °C, [α]D +2932 (c 0.05, CHCl3). Found (%):
C, 65.63; H, 6.02; N, 7.22. C32H35N3NiO4. Calculated (%):
C, 65.77; H, 6.04; N, 7.19. 1H NMR, δ: 1.07 (d, 3 H,
>CH—CH(Me), 3J = 6.4 Hz); 1.98, 2.09 (both s, 3 H each,
Me); 2.03—2.17 (m, 3 H, βꢀH Pro, γꢀH Pro); 2.55 (m, 1 H,
βꢀH Pro); 3.28 (qd, 1 H, >CH—CH(Me), J = 6.4 Hz, J =
2.2 Hz); 3.33 (d, 1 H, NCH2Ar, J = 12.3 Hz); 3.66 (dd, 1 H,
αꢀH Pro, J = 10.4 Hz, J = 6.4 Hz); 3.36 (m, 1 H, δꢀH Pro);
3.56 (s, 3 H, OMe); 3.61 (d, 1 H, CH—CH(Me), J = 2.2 Hz);
3.79 (m, 1 H, δꢀH Pro); 4.17 (d, 1 H, NCH2Ar, J = 12.3 Hz);
6.54—6.60 (m, 2 H, H arom.); 6.98—7.08 (m, 3 H, H arom.);
7.38 (br.d, 1 H, H arom., J = 7.5 Hz); 7.43—7.68 (m, 4 H,
H arom.); 8.00 (d, 1 H, H arom., J = 8.6 Hz); 8.49 (d, 1 H,
H arom., 4J = 1.9 Hz).
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(2S,3S)ꢀOꢀethylthreoninatoꢀ
N,N´,N″,O]nickel(II) (9a). The yield was 90%, m.p. 166—168 °C,
25
AcOEt—CHCl3 (3 : 1)), m.p. 188—190 °C, [α]D +2084.7
(c 0.05, CHCl3). Found (%): C, 67.73; H, 5.72; N, 7.74.
3
3
C31H31N3NiO3. Calculated (%): C, 67.42; H, 5.62; N, 7.61.
3
2
1H NMR, δ: 1.64 (d, 3 H, >C=CH(Me), J = 7.4 Hz); 1.97,
3
3
2.04 (both s, 3 H each, Me); 2.14 (m, 1 H, βꢀH Pro); 2.34, 2.65
(both m, 1 H each, γꢀH Pro); 2.74 (m, 1 H, βꢀH Pro); 2.83 (dd,
1 H, δꢀH Pro, 3J = 9.2 Hz, 3J = 6.4 Hz); 3.42 (dd, 1 H, αꢀH Pro,
3
2
3
3J = 11.0 Hz, J = 6.4 Hz); 3.65 (m, 1 H, δꢀH Pro); 3.98, 4.10
(both d, 1 H each, NCH2Ar, 2J = 12.6 Hz); 5.02 (q, 1 H,
>C=CH(Me), 3J = 7.4 Hz); 6.60 (ddd, 1 H, H arom., 3J =
8.4 Hz, 3J = 6.8 Hz, 4J = 1.1 Hz); 6.78 (dd, 1 H, H arom., 3J =
8.4 Hz, 4J = 1.8 Hz); 7.02 (ddd, 1 H, H arom., 3J = 8.9 Hz, 3J =
3
3
4
6.8 Hz, J = 1.8 Hz); 7.20—7.42 (m, 4 H, H arom.); 7.56 (m,
3 H, H arom.); 7.64 (dd, 1 H, H arom., 3J = 8.9 Hz, 4J =
1.1 Hz); 8.23 (dd, 1 H, H arom., 3J = 7.6 Hz, 4J = 1.7 Hz).
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(Z )ꢀ2ꢀaminobutꢀ2ꢀenoatoꢀ
N,N´,N″,O]nickel(II) (Zꢀ7b). The yield was 40%, Rf 0.64 (SiO2,
AcOEt—CHCl3 (3 : 1)), m.p. >250 °C, [α]D25 +3141.3 (c 0.025,
CHCl3). Found (%): C, 67.48; H, 5.68; N, 7.74. C31H31N3NiO3.
Calculated (%): C, 67.42; H, 5.62; N, 7.61. 1H NMR, δ: 0.92 (d,
3 H, >C=CH(Me), J = 7.6 Hz); 1.99, 2.05 (both s, 3 H each,
Me); 2.18 (m, 1 H, βꢀH Pro); 2.22, 2.63 (both m, 1 H each,
γꢀH Pro); 2.78 (m, 1 H, βꢀH Pro); 2.92 (dd, 1 H, δꢀH Pro, 3J =
9.4 Hz, 3J = 6.4 Hz); 3.22 (dd, 1 H, αꢀH Pro, 3J = 11.0 Hz, 3J =
6.4 Hz); 3.63 (m, 1 H, δꢀH Pro); 3.96, 4.23 (both d, 1 H each,
NCH2Ar, 2J = 12.6 Hz); 5.56 (q, 1 H, >C=CH(Me), 3J =
7.6 Hz); 6.62 (ddd, 1 H, H arom., 3J = 8.4 Hz, 3J = 6.6 Hz, 4J =
1.3 Hz); 6.80 (dd, 1 H, H arom., 3J = 8.4 Hz, 4J = 1.8 Hz); 6.96
25
[α]D +2409 (c 0.05, CHCl3). Found (%): C, 61.61; H, 5.38;
N, 6.91. C31H32ClN3NiO4. Calculated (%): C, 61.57; H, 5.33;
N, 6.95. 1H NMR, δ: 0.98 (d, 3 H, >CH—CH(Me), 3J = 6.4 Hz);
1.37 (t, 3 H, OCH2Me, 3J = 7.0 Hz); 2.04—2.20 (m, 2 H,
γꢀH Pro, βꢀH Pro); 2.51 (m, 1 H, βꢀH Pro); 2.86 (m, 1 H,
γꢀH Pro); 3.28 (m, 1 H, δꢀH Pro); 3.46 (qd, 1 H,
>CH—CH(Me), 3J = 6.4 Hz, 3J = 2.2 Hz); 3.48 (dd, 1 H,
αꢀH Pro, 3J = 10.6 Hz, 3J = 6.6 Hz); 3.65 (d, 1 H,
>CH—CH(Me), 3J = 2.2 Hz); 3.81 (m, 1 H, δꢀH Pro); 3.72 (q,
2 H, OCH2Me, 2J = 7.0 Hz); 3.33 (d, 1 H, NCH2Ar, 2J =
12.2 Hz); 4.19 (d, 1 H, NCH2Ar, J = 12.7 Hz); 6.59—6.63,
7.01—7.12 (both m, 2 H each, H arom.); 7.18 (td, 1 H, H arom.,
3J = 7.6 Hz, 4J = 1.7 Hz); 7.31—7.39, 7.45—7.68 (both m,
3 H each, H arom.); 8.06 (d, 1 H, H arom., J = 8.6 Hz); 8.26
(dd, 1 H, H arom., 3J = 7.6 Hz, 4J = 1.6 Hz).
(S)ꢀ[({2ꢀ[1ꢀ(3,4ꢀDimethylbenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(2S,3S)ꢀOꢀethylthreoninatoꢀ
N,N´,N″,O]nickel(II) (9b). The yield was 87%, m.p. 235—237 °C,
2
3
3
3
4
(ddd, 1 H, H arom., J = 8.7 Hz, J = 6.9 Hz, J = 1.8 Hz);
7.02—7.46 (m, 4 H, H arom.); 7.62 (m, 3 H, H arom.); 7.98 (dd,
1 H, H arom., 3J = 8.7 Hz, 4J = 1.1 Hz); 8.42 (dd, 1 H, H arom.,
3J = 7.7 Hz, 4J = 1.8 Hz).
25
[α]D +3129 (c 0.05, CHCl3). Found (%): C, 66.38; H, 6.27;
Addition of the alkoxide ions to complexes 7a,b was carried
out as described earlier.19,20 Both the individual (E )ꢀ and
(Z )ꢀisomers and their mixtures (2 : 1 for 7a and 3 : 2 for 7b)
obtained in the synthesis were used. The base : complex ratio
was 3 : 1.
(S)ꢀ[({2ꢀ[1ꢀ(2ꢀChlorobenzyl)pyrrolidineꢀ2ꢀcarboxꢀ
amido]phenyl}{phenyl}methylidene)ꢀ(2S,3S)ꢀOꢀmethylthreoꢀ
ninatoꢀN,N´,N″,O]nickel(II) (8a). The yield was 90%, m.p.
N, 6.99. C33H37N3NiO4. Calculated (%): C, 66.24; H, 6.23;
N, 7.02. 1H NMR, δ: 1.08 (d, 3 H, >CH—CH(Me), 3J = 6.4 Hz);
1.37 (t, 3 H, OCH2Me, 3J = 7.0 Hz); 1.97 (s, 3 H, Me);
2.04—2.14 (m, 3 H, γꢀH Pro, βꢀH Pro); 2.09 (s, 3 H, Me); 2.51
(m, 1 H, βꢀH Pro); 3.31—3.44 (m, 2 H, αꢀH Pro, δꢀH Pro); 3.33
(d, 1 H, NCH2Ar, 2J = 12.2 Hz); 3.34 (qd, 1 H, >CH—CH(Me),
3
3
3J = 6.4 Hz, J = 2.2 Hz); 3.65 (d, 1 H, >CH—CH(Me), J =
2
2.2 Hz); 3.72 (q, 2 H, OCH2Me, J = 7.0 Hz); 3.73 (m, 1 H,

Chiral Ni complexes with 2ꢀaminobutenoic acid
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
449
Table 2. Selected crystallographic parameters and a summary of
data collection for complexes 4a,b
parameters for complexes 4a,b have been deposited with the
Cambridge Crystallographic Data Center.
We are grateful to Yu. N. Belokon´ for fruitful discusꢀ
sion of the results obtained.
This work was financially supported by the Internaꢀ
tional Scientific and Technical Center (Grants ISTC 2780
and Aꢀ1247) and the Russian Foundation for Basic Reꢀ
search (Project No. 02ꢀ03ꢀ32050).
Parameter
4a
4b
Molecular formula
Molecular mass
T/K
Crystal system
Space group
a/Å
b/Å
c/Å
V/Å3
C28H26ClN3NiO3 C30H31N3NiO3
546.68
173
540.29
105
Orthorhombic
P212121
9.3354(19)
10.033(2)
25.919(5)
2427.6(8)
4
1.496
1136
0.946
58
P212121
9.3420(7)
10.5929(8)
26.297(2)
2602.3(3)
4
1.379
1136
0.782
56
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2 H, H arom.); 6.98—7.04 (m, 3 H, H arom.); 7.39—7.65 (m,
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Received December 7, 2004;
in revised form November 2, 2005