New N-nitrosoamines 1. Synthesis and nitrosative cleavage of the Mannich bases derived from nitrogen-containing heterocycles and primary aliphatic amines

Article abstract of DOI:10.1023/A:1013094720611

The reactions of isatin, benzotriazole, and succinimmide with formaldehyde and methylamine yield monoamines RCH₂N(Me)CH₂R and methylenediamines RCH₂N(Me)CH₂N(Me)CH₂R. The use of ethylenediamine as the amino component affords N,N′ -disubstituted imidazolidines, while the reactions with 3-aminopropan-1-ol give N-substituted tetrahydro-1.3-oxazines. RCH₂NBu¹₂ was obtained from succinimide, formaldehyde, and diisobutylamine. Nitrosative cleavage of the amines obtained was studied: it was shown that monoamines and methylenediamines give N-nitrosoamines RCH₂N(NO)Me, which were structurally characterized by X-ray diffraction analysis. RCH₂NBu¹₂ affords diisobutylnitrosamine, while imidazolidines transform into dinitroso compounds RCH₂N(NO)CH₂CH₂N(NO)CH₂R.

Full text of DOI:10.1023/A:1013094720611

1
630
Russian Chemical Bulletin, International Edition, Vol. 50, No. 9, pp. 1630—1638, September, 2001
New N-nitrosoamines
. Synthesis and nitrosative cleavage of the Mannich bases
1
derived from nitrogen-containing heterocycles and primary aliphatic amines
A. G. Korepin,a« P. V. Galkin,a N. M. Glushakova,a V. P. Lodygina,a I. L. Eremenko,b
S. E. Nefedov, and L. T. Eremenkoa
b
aInstitute of Problems of Chemical Physics, Russian Academy of Sciences,
8 Institutskii prosp., 142432 Chernogolovka, Moscow Region, Russian Federation.
1
Fax: +7 (096) 515 3588. E-mail: sma@icp.ac.ru
bN. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
1 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (095) 952 1279. E-mail: ilerem@ionchran.rinet.ru
3
The reactions of isatin, benzotriazole, and succinimide with formaldehyde and methylamine
yield monoamines RCH N(Me)CH R and methylenediamines RCH N(Me)CH N(Me)CH R.
2
2
2
2
2
The use of ethylenediamine as the amino component affords N,N´-disubstituted imidazolidines,
while the reactions with 3-aminopropan-1-ol give N-substituted tetrahydro-1,3-oxazines.
i
RCH NBu was obtained from succinimide, formaldehyde, and diisobutylamine. Nitrosative
2
2
cleavage of the amines obtained was studied; it was shown that monoamines and
methylenediamines give N-nitrosoamines RCH N(NO)Me, which were structurally charac-
2
i
terized by X-ray diffraction analysis. RCH NBu affords diisobutylnitrosamine, while
2
2
imidazolidines transform into dinitroso compounds RCH N(NO)CH CH N(NO)CH R.
2
2
2
2
Key words: aminomethylation, nitrogen-containing heterocycles, primary aliphatic amines,
nitrosative cleavage of tertiary amines, N-nitrosoamines, X-ray diffraction analysis, 1H NMR
and IR spectroscopy.
N-nitrosoamines possessing unusual chemical and
was established that the reactions with primary alkyl-
amines mostly yield tertiary amines, i.e., an NH acid,
formaldehyde, and an alkylamine react in the molar
ratio 2 : 2 : 1.12,13
biological properties1 have long attracted the attention
of many specialists.
As a rule, N-nitrosoamines are obtained by nitrosation
of secondary amines2
tiary amines.8
—7
or nitrosative cleavage of ter-
We found that the reactions of benzotriazole 1b and
succinimide 1c with formaldehyde and methylamine in
—11
i
In our opinion, secondary or tertiary amines contain-
ing different heterocyclic fragments are especially attrac-
tive as the starting compounds since the latter are parts
of various drugs. The present work is devoted to the
synthesis of new tertiary amines containing heterocyclic
fragments, study of their nitrosative cleavage, and eluci-
dation of structures of the N-nitrosoamines obtained.
the ratio 2 : 2 : 1 smoothly occur in Pr OH at ambient
temperature, giving tertiary amines 2b and 2c in
80—82% yields (Scheme 1). Heating was required for
poorly soluble isatin 1a, and tertiary amine 2a was
obtained in moderate yield (see Scheme 1).
Scheme 1
Results and Discussion
Me
The starting amines were synthesized by amino-
methylation (the Mannich reaction). The substrates to
be aminomethylated were nitrogen-containing hetero-
cycles with a mobile hydrogen atom at the N atom (NH
acids), namely, isatin (1a), benzotriazole (1b), and
succinimide (1c). The amino components were primary
aliphatic amines (methylamine, ethylenediamine, and
2
RH + 2CH O + MeNH
R
N
R
2
2
1
a—c
2a—c
Hereinafter:
O
O
N
N
R =
O (a),
N (b),
N (c)
N
3
-aminopropan-1-ol).
O
Tertiary monoamines. Aminomethylation of NH ac-
ids by primary aliphatic amines is studied to a lesser
extent than that by secondary amines. Nevertheless, it
The reaction of succinimide 1c with formaldehyde
and diisobutylamine affords amine 3 (Scheme 2).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1553—1561, September, 2001.
066-5285/01/5009-1630 $25.00 ©ꢀ2001 Plenum Publishing Corporation
1

Nitrosative cleavage of the Mannich bases
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001 1631
Scheme 2
Scheme 5
i
i
RH
+
CH O
2
+
Bu NH
2
RCH NBu
2
RH + 2CH O + H N
OH
2
2
2
–
H O
–
2H O
2
2
1
a—c
1
c
3
Tertiary diamines. The compositions and structures
of the Mannich reaction products are known to depend
on the ratio of the starting reagents.13 Thus the reaction
of isatin 1a with formaldehyde and methylamine in the
ratio 2 : 4 : 2.9 gave diamine 4a as the major product
R
N
O
6
a—c
(
Scheme 3), while benzotriazole 1b reacts with formal-
The structures of the tertiary amines obtained were
established by elemental analysis and 1H NMR and IR
spectroscopy (Table 1). The 1H NMR spectrum of
methylenediamine 4a could not be recorded because of
its low solubility in available deuterated solvents.
Nitrosative cleavage of tertiary mono- and diamines.
The nitrosative cleavage is usually performed by heating
a mixture of an amine and sodium nitrite in aqueous
acetic acid for a long time.8,9 Nitrosamines were also
dehyde and methylamine in the ratio 2 : 5 : 11 to form
diamine 4b (Scheme 3).
Scheme 3
Me Me
2
RH + 3CH O + 2MeNH
R
N
N
R
2
2
prepared by treating tertiary amines with nitric acid in
acetic anhydride10 or with nitrogen dioxide.11 Drastic
1
a,b
4a,b
reaction conditions and a complicated isolation proce-
dure often preclude the preparation of nitrosamines in
high yields.
No similar diamine was obtained from succinimide
c; with a fivefold excess of methylamine, aminolysis
occurred, while a decrease in its excess results only in
monoamine 2c.
The use of ethylenediamine as the amino component
in the Mannich reactions with compounds 1a—c af-
forded a group of cyclic tertiary diamines, namely,
imidazolidines 5a—c (Scheme 4).
1
Although we found no examples of the application
of this reaction for the synthesis of nitrosamines from
the Mannich bases, one could expect that these would
undergo such a cleavage under milder conditions and
more smoothly, considering the lability of the Namine—C
bonds. In fact, monoamines 2a—c and diamines 4a,b
underwent nitrosative cleavage when treated with a mix-
ture of anhydrous acetic acid and sodium nitrite at
ambient or even reduced temperature to form nitros-
amines 7a—c (Scheme 6).
Scheme 4
NH2
2
RH + 3CH O + H N
2
2
1
a—c
Scheme 6
R
N
N
R
Me
N
Me
N
NaNO2
R
R
R
NO
5
a—c
AcOH
2
a—c
7a—c
The reactions are carried out, as in the synthesis of
a,b, in Pr OH at room temperature or with moderate
AcOH
i
4
NaNO2
heating; compounds 5a—c were isolated in high yields.
N-Substituted tetrahydro-1,3-oxazines. The reac-
tions with 3-aminopropan-1-ol gave N-substituted
tetrahydro-1,3-oxazines 6a—c (Scheme 5)*.
Me Me
R
N
N
R
4
a,b
As in the synthesis of imidazolidines 5a—c, the
process includes two consecutive aminomethylation re-
actions. Unlike the formation of 5a—c through two
N-aminomethylation reactions, N- and O-amino-
methylations are involved in the latter case. In both
cases, the intramolecular cyclization provides high yields
of products with the stoichiometric ratio of the starting
reagents.
The products were isolated by simply diluting the
reaction mixture with water and separating the resulting
precipitate. (Nitrosamine 7c, which is well soluble in
aqueous acetic acid, is isolated by extraction with
CH Cl ).
2
2
It should be noted that the nitrosative cleavage of
monoamines 2a—c is accompanied by the loss of a
substituent containing the heterocyclic fragment, while
methylenediamines 4a,b undergo the cleavage of the
*
For details see Ref. 14.

1
632
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001
Korepin et al.
Table 1. Characteristics of the Mannich bases
Com-
poundformula
Molecular
Found
Calculated
1H NMR
δ (J/Hz)
IR
(
%)
–
1
(solvent),
(KBr), ν/cm
C
H
N
2
2
a
Ñ19Í15N O4
65.12
4.59
4.33
11.78
12.03
(CDCl ): 2.52 (s, 3 H, ÑÍ N);
2940, 2830, 1360 (CH , CH );
3 2
1735 (Ñ=Î); 1610, 1470, 765
(Àr); 1330, 1310, 1255 (їN)
3
3
3
6
5.32
4.70 (s, 4 H, NÑÍ N); 7.04, 7.62
2
(
both d, 2 H each, H(4,7), J = 8.0 );
.15, 7.56 (both t, 2 H each, H(5,6),
J = 8.0)
(CDCl ): 2.53 (s, ÑÍ, ÑÍ N);
7
b*
Ñ15Í15N7
61.30
1.42
5.20
5.15
33.45
33.43
3061, 3000, 1610, 1590, 1495,
1455, 790, 780, 745 (Ar);
2961, 2876, 2831, 1435, 1425,
1400, 1370
3
3
6
5.60 (s, 4 H, NCH N); 7.40, 7.52
2
(
7
both t, 2 H each, H(5,6), J = 8.0);
.67, 8.09 (both d, 2 H each, Í(4,7),
J = 8.0)
(ÑÍ , ÑÍ ); 1325, 1310,
3
2
1
280, 1270 (їN)
2
c
Ñ11Í15N O4
52.02
2.17
5.91
5.97
16.70
16.59
(CDCl ): 2.36 (s, 3 H, ÑÍ N);
2.70 (s, 8 H, CH Ñ(Î)); 4.42
2
2985, 2945, 2860, 2810,
1455, 1410, 1356 (ÑÍ3,
3
3
3
5
(
s, 4 H, NCH N)
ÑH ); 1756, 1700 (Ñ=Î);
2
2
1
1
285, 1265, 1250, 1175,
155, 1070, 1045 (їN,
іÑ)
3
4
4
Ñ13Í24N O2
64.77
4.97
10.16
10.06
11.75
11.66
2960, 2865, 1350 (ÑÍ );
1775, 1705 (Ñ=Î); 1285,
2
2
6
1
235, 1150, 1090, 1050
їN, їÑ)
2960, 2865, 1435, 1355
(ÑÍ , ÑÍ ); 1725 (Ñ=Î);
(
a
b
Ñ21Í20N O4
64.37
4.28
5.00
5.14
14.06
14.28
4
6
3
2
1
1
605, 1465, 765 (Ar); 1330,
305, 1240 (C—N)
Ñ17Í20N8
60.89
0.70
5.77
5.99
33.30
33.31
(CDCl ): 2.46 (s, 6 H, CH N);
3.28 (s, 2 H, CH ); 5.69 (s, 4 H,
2
2975, 2956, 2940, 2876,
2845, 2815, 1430, 1385,
3
3
6
NCH N); 7.37, 7.50 (both t,
1370 (ÑÍ , ÑÍ ); 3087,
3 2
2
2
H each, Í(5,6), J = 8.0); 7.69, 8.08 3060, 3021, 1610, 1490,
both d, 2 H each, Í(4,7), J = 8.0) 1450, 775, 765, 755, 745
Ar); 1325, 1305, 1290,
280 (C—N)
(DMSO-d ): 2.90 (s, 4 H, NCH ); 2930, 2845, 1385, 1366,
6 2
(
(
1
5
5
à
b
Ñ21Í18N O4
64.34
4.61
4.80
4.65
14.42
14.35
4
6
3.63 (s, 2 H, NCH N); 4.57 (s,
1350 (ÑÍ ); 1735 (Ñ=Î);
2
2
4
2
H, CH NC(O)); 7.14, 7.64 (both t,
H each, Í(5,6), J = 7.6); 7.25, 7.55 1050 (ring)
1615, 1470, 765 (Ar); 1255,
2
(
both d, 2 H each, Í(4,7), J = 7.6)
Ñ17Í18N8
60.96
1.06
5.37
5.43
33.82
33.51
(CD CN): 2.90 (s, 4 H,
3056, 1613, 1496, 1451,
797, 767, 743 (Ar); 2939,
2870, 2840, 1435, 1388,
3
6
NCH CH N); 3.82 (s, 2 H,
2
2
NCH ); 5.50 (s, 4 H, NCH=N);
2
7
.40, 7.50 (t, 2 H each, H(5,6),
1370 (ÑÍ ); 1196, 1061
2
J = 7.7); 7.65, 7.99 (both d, 2 H each, (ring)
Í(4,7), J = 7.7)
5
6
ñ
à
Ñ13Í18N O4
53.08
3.05
6.26
6.16
19.36
19.04
(CDCl ): 2.70 (s, 8 H, CH C(Î));
2950, 2930, 2900, 2850,
4
3
2
5
2.87 (s, 42 H, NCH CH N); 3.58
1435, 1405, 1345 (ÑÍ );
2
2
2
(
s, 2 H, NCH ); 4.30 (s, 4 H,
1770, 1695 (Ñ=Î); 1230,
1080 (ring)
3062, 3029, 1616, 1496,
1454, 800, 743 (Ar); 2973,
2951, 2930, 2870, 2837,
2
NCH N)
2
Ñ13Í14N O3
63.53
3.40
5.59
5.73
11.10
11.37
(CD CN): 1.60 (quint, 2 H,
2
3
6
CH CH CH , J = 5.0 ); 2.98 (t, 2 H,
2 2 2
NCH CH , J = 5.0 ); 3.70 (t,
2
2
2
2
7
H, OCH CH , J = 5.0); 4.41 (s,
1382, 1367, 1340 (CH );
2
2
2
H, NCH O); 5.63 (s, 2 H, NCH N); 1205, 1181, 1046, 1001,
2
2
.41, 7.55 (both dd, 1 H each, H(6),
1205, 1181, 1046, 1001,
977, 950, 884 (oxazine)
J = 8.0, H(5), J = 8.0);
.75, 8.00 (both d, 1 H each, H(7),
J = 8.0, H(4), J = 8.0)
7
(
to be continued)

Nitrosative cleavage of the Mannich bases
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001 1633
Table 1 (continued)
Com-
poundformula
Molecular
Found
Calculated
1H NMR
δ (J/Hz)
IR
(
%)
–
1
(solvent),
(KBr), ν/cm
C
H
N
6
b
Ñ11Í14N O
60.32
6.32
6.47
26.01
25.67
(CD CN): 1.60 (quint, 2 H,
CH CH CH , J = 5.0); 2.98 (t, 2 H,
2 2 2
3098, 3032, 2993, 1613,
1508, 1466, 728, 713 (Ar);
2960, 2924, 2876, 2870,
2837, 1382, 1367, 1340,
4
3
6
0.54
NCH CH , J = 5.0 ); 3.70 (t,
2
2
2
2
H, OCH CH , J = 5.0); 4.41 (s,
2 2
H, NCH O); 5.63 (s, 2 H,
(CH ); 1205, 1181, 1046,
2
2
NCH N); 7.41, 7.55 (both d, 1 H
each, H(6), J = 8.0, H(5), J = 8.0);
1001, 977, 950, 884
(oxazine)
2
7
.75, 8.00 (both d, 1 H each, H(7),
J = 8.0, H(4), J = 8.0)
6
ñ
Ñ Í N O
54.24
4.53
6.92
7.12
14.40
14.13
(CD Cl ): 1.11 (quint, 2 H,
ÑÍ CH CH , J = 5.1, 4.8); 2.68
2 2 2
2987, 2969, 2954, 2924,
2864, 2810, 2750, 2726,
1442, 1418, 1409, 1388,
9
14
2
3
2
2
5
(
s, 4 H, CH Ñ(Î)); 2.92 (t, 2 Í,
2
NCH CÍ , J = 5.1); 3.73 (t, 2 H,
1367, 1349 (CH ); 1763,
2
2
2
ÑÍ ÑÍ Î, J = 4.8); 4.28 (s, 2 Í,
1697 (C=O); 1223, 1058,
983, 899 (oxazine)
2
2
NÑÍ Î); 4.42 (s, 2 Í, NCH N)
2
2
*
See Ref. 13.
N—C bonds of the methylenediamine fragment and no
loss of the heterocycle takes place.
mixture of AcOH with Ac O and changed the order of
mixing the reagents.
2
Cyclic diamines 5a—c undergo a similar cleavage to
give bisnitrosamines 8a—c (Scheme 7).
H(13a)
C(12)
C(11)
H(14a)
C(13)
O(6)
Scheme 7
C(18)
NO
C(17)
C(14)
H(15a)
O(5)
NaNO2
AcOH
N
R
R
N
N
R
R
N
NO
C(16)
N(4)
C(15)
H(16a)
5
a—c
8a—c
O(1)
C(19)
H(20b)
The nitrosative cleavage of amine 3 occurs with the
H(10a)
splitting of the heterocyclic fragment to yield the
H(20a)
C(10)
known15,16 diisobutylnitrosamine 9 (Scheme 8).
N(3)
N(2)
N(5)
H(21b)
H(10b)
Scheme 8
H(21c)
H(10c)
N(6)
O(4)
C(20)
NaNO2
i
i
C(9)
Bu 2N
R
Bu 2N NO
H(21a)
H(9a)
AcOH
H(2a)
3
9
H(9b)
O(2)
In the reactions studied, all tertiary amines derived
from isatin and succinimide give the corresponding
nitrosamines in high yields. Benzotriazole derivatives 2b
and 4b afford nitrosamine 7b in but moderate yield.
Bisnitrosamine 8b could be obtained from cyclic di-
amine 5b in very low yield. The low yields of nitros-
amines 7b and 8b may be attributed to the known fact17
of hydrolytic instability of aminomethylated benzo-
triazoles. To reduce the contribution from the hydro-
lytic transformations of these amines during their
nitrosative cleavage, we carried out the reaction in a
N(1)
C(2)
C(8)
C(1)
H(3a)
C(4)
C(3)
C(7)
O(3)
C(6)
C(5)
H(4a)
H(5a)
Fig. 1. Structures of two independent molecules in com-
pound 7a.

1
634
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001
Korepin et al.
Table 2. Characteristics of N-nitrosoamines
Com-
poundformula
Molecular
Found
Calculated
1H NMR
δ (J/Hz)
IR
(
%)
–
1
(solvent),
(KBr), ν/cm
C
H
N
7
7
7
8
8
à
b
ñ
à
b
Ñ10Í N O
54.95
4.42
4.14
19.05
19.17
(CD Cl ): 3.07 (s, 3 Í, ÑH N);
6.10 (s, 2 Í, NCH N); 7.16, 7.68
2
3030, 1615, 1470, 760 (Ar);
2920, 2705, 1445, 1345
(ÑÍ , ÑÍ ); 1745, 1735
3 2
(Ñ=Î); 1430, 1035
(N—N=O)
3090, 3066, 3021, 1614,
1492, 1454, 785, 760, 751
(Ar); 2936, 1422, 1367
9
3
3
2
2
3
5
4.79
(
7
both d, 1 H each, Í(4,7), J = 7.3);
.23, 7.67 (both t, 1 H each, Í(5,6),
J = 7.3)
Ñ Í N Î
50.48
0.26
5.11
4.74
36.82
36.63
(CD CN): 3.00 (s, 3 Í, ÑÍ N);
8
9
5
3
3
5
7.02 (s, 2 Í, NCH N); 7.43, 7.58
2
(
(
both t, 1 H each, Í(5,6)); 7.74, 8.05
both d, 1 H each, Í(4,7))
(ÑÍ , ÑÍ ); 1459, 1031
3
2
(
N—N=O)
Ñ Í N Î
42.19
2.10
5.12
5.30
25.04
24.55
(CD CN): 2.73 (s, 4 Í, ÑÍ Ñ(Î));
3015, 2935, 1420, 1400,
1350 (ÑÍ , ÑÍ ); 1775,
6
9
3
3
3
2
4
3.00 (s, 3 Í, ÑÍ N); 5.77 (s, 2 Í,
3
3
2
NCH N)
1715 (Ñ=Î); 1445, 1025
N—N=O); 1285, 1255, 1165,
070 (C—N)
2
(
1
Ñ20Í16N Î6
55.52
5.05
5.12
3.69
19.05
19.26
3013, 1610, 1470, 760 (Ar);
2925, 2849, 1420, 1340
6
5
(
ÑÍ ); 1735 (Ñ=Î); 1465,
2
1
1
035, 1010 (N—N=O); 1300,
250 (C—N)
Ñ16Í16N10Î2
49.95
0.52
4.12
4.24
37.00
36.82
3070, 3020, 1613, 1492,
1453 sh, 790, 746 (Ar);
5
2
1
9
930, 2854, 1428, 1371,
351, 1341 (ÑÍ ); 1467,
2
65 (N—N=O); 1230, 1194
(
C—N)
8
c
C12H16N O6
42.74
2.35
4.56
4.74
37.00
24.70
2945, 1415, 1350 (ÑÍ );
1775, 1707 (Ñ=Î); 1455,
6
2
4
1
1
060 (N–N=O); 1300, 1280,
175, 1125 (їN, C—C)
Our attempts to perform nitrosative cleavage of
neighboring C atoms and the N atom (the deviations of
the N(2) and N(5) atoms in 7a (see Fig. 1) or the N(2)
atom in 7b (see Fig. 2) are 0.0105 and 0.0566 Å in 7a
tetrahydro-1,3-oxazines 6a—c failed; the expected
N-nitroso derivatives were not isolated from the result-
ing mixtures. This may partly be due to the hydrolysis of
the nitrite group formed upon O-nitrosation when the
reaction mixture is diluted with water. (These investiga-
tions are in progress and their results will be published
elsewhere.)
H(7)
C(7)
C(6)
H(6)
N(5)
C(8)
All the nitrosamines obtained were identified by
elemental analysis and IR spectroscopy (Table 2). The
structures of mononitrosamines 7a—c were also con-
firmed by 1H NMR spectroscopic data. The 1H NMR
spectra of bisnitrosamines 8a,c could not be recorded
because of their low solubilities in available deuterated
solvents.
H(5)
N(4)
C(5)
C(3)
H(21)
C(2)
N(3)
C(4)
H(4)
H(22)
Nitrosamines 7a,b were structurally characterized by
X-ray diffraction analysis (Figs. 1, 2). The N(NO)Me
fragments in both molecules are geometrically similar
N(2)
H(13)
(
(
Tables 3, 4). For example, the NNO group is nonlinear
the N—N—O angle is 111.0(4)° and 117.9(4)° in 7a for
N(1)
C(1)
H(11)
two independent molecules and 114.3(2)° in 7b), which
is not surprising since the nitroso N atom has a free
lone electron pair not involved formally in bonding. The
second N atom virtually lies in the plane containing the
O(1)
H(12)
Fig. 2. Structure of 7b.

Nitrosative cleavage of the Mannich bases
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001 1635
Table 3. Selected geometrical parameters of compound 7a
Bond
d/Å
Bond
d/Å
Bond
d/Å
Molecule À
N(1)—C(1)
N(2)—N(3)
N(3)—O(1)
C(1)—C(2)
C(3)—C(4)
C(6)—C(7)
1.482(4) N(1)—C(8)
1.376(5) N(2)—C(9)
1.223(6) O(2)—C(8)
1.369(5) C(1)—C(6)
1.363(7) C(4)—C(5)
1.530(5) C(7)—C(8)
1.3904)
1.463(6)
1.249(5)
1.340(5)
1.509(7)
1.453(5)
N(1)—C(9)
N(2)—C(10)
O(3)—C(7)
C(2)—C(3)
C(5)—C(6)
1.412(4)
1.374(6)
1.216(5)
1.406(5)
1.406(5)
Molecule Â
N(4)—C(17) 1.341(5)
N(4)—C(18)
N(5)—C(20)
1.363(5)
1.449(5)
1.182(5)
1.447(5)
1.344(7)
1.656(5)
N(4)—C(20)
N(5)—C(21)
O(6)—C(19)
C(12)—C(19) 1.359(5)
C(15)—C(16) 1.413(6)
1.462(5)
1.518(6)
1.211(5)
N(5)—N(6)
N(6)—O(4)
1.2325)
1.234(5) O(5)—C(18)
C(12)—C(13) 1.366(5) C(12)—C(17)
C(13)—C(14) 1.266(6) C(14)—C(15)
C(16)—C(17) 1.402(5) C(18)—C(19)
Angle
ω/deg
Angle
ω/deg
Molecule À
C(1)—N(1)—C(8)
C(8)—N(1)—C(9)
N(3)—N(2)—C(10)
N(2)—N(3)—O(1)
N(1)—C(1)—C(6)
C(1)—C(2)—C(3)
C(3)—C(4)—C(5)
C(1)—C(6)—C(5)
C(5)—C(6)—C(7)
O(3)—C(7)—C(8)
N(1)—C(8)—O(2)
O(2)—C(8)—C(7)
106.9(2)
127.0(3)
126.6(4)
111.0(4)
110.9(3)
118.0(4)
123.3(4)
122.9(4)
129.7(4)
126.9(4)
122.8(3)
126.8(4)
C(1)—N(1)—C(9)
N(3)—N(2)—C(9)
C(9)—N(2)—C(10)
N(1)—C(1)—C(2)
C(2)—C(1)—C(6)
C(2)—C(3)—C(4)
C(4)—C(5)—C(6)
C(1)—C(6)—C(7)
O(3)—C(7)—C(6)
C(6)—C(7)—C(8)
N(1)—C(8)—C(7)
N(1)—C(9)—N(2)
126.1(2)
111.3(3)
122.0(3)
124.6(3)
124.5(3)
119.3(4)
112.1(4)
107.4(3)
128.1(4)
104.9(3)
109.9(3)
111.0(3)
Molecule Â
C(17)—N(4)—C(18)
C(18)—N(4)—C(20)
N(6)—N(5)—C(21)
N(5)—N(6)—O(4)
C(13)—C(12)—C(19)
C(12)—C(13)—C(14)
C(14)—C(15)—C(16)
N(4)—C(17)—C(12)
C(12)—C(17)—C(16)
N(4)—C(18)—C(19)
O(6)—C(19)—C(12)
C(12)—C(19)—C(18)
114.3(3)
121.1(3)
118.0(4)
117.9(4)
133.1(4)
124.5(4)
126.2(4)
110.0(3)
119.6(3)
101.5(3)
136.8(4)
105.2(3)
C(17)—N(4)—C(20)
N(6)—N(5)—C(20)
C(20)—N(5)—C(21)
C(13)—C(12)—C(17)
C(17)—C(12)—C(19)
C(13)—C(14)—C(15)
C(15)—C(16)—C(17)
N(4)—C(17)—C(16)
N(4)—C(18)—O(5)
O(5)—C(18)—C(19)
O(6)—C(19)—C(18)
N(4)—C(20)—N(5)
123.8(3)
121.3(4)
120.2(3)
117.9(3)
108.9(3)
118.4(4)
113.4(4)
130.4(3)
130.5(4)
127.9(4)
118.0(3)
112.9(3)
and by 0.0082 Å in 7b). Although the geometrical
parameters of the N(NO)Me fragment in two indepen-
dent molecules of compound 7a are somewhat non-
equivalent (see Table 3) (probably, because of packing
effects, which redistribute the electron density in this
fragment), the angular conformation of the NNO frag-
ment in both nitroso compounds is typical of such
organic derivatives,18 sharply differing from the linear
one characteristic of metal nitrosyl complexes where the
lone electron pair of the N atom is involved in bonding
to the metal center, which makes the N—O and M—N
distances significantly shorter.19
the nitrosative cleavage of the resulting Mannich bases
is proposed.
Experimental
The starting high-purity NH acids and amines (≥98%) were
used without additional purification. Solvents for reaction and
recrystallization purposes were reagent and analytical grades.
1H NMR spectra were recorded on an NMR spectrometer
with a superconducting magnet (294 MHz) (the instrument was
designed and manufactured at the Institute of Problems of
Chemical Physics, Russian Academy of Sciences). IR spectra
(
KBr) were recorded on a Specord M82 spectrophotometer.
Thus, a route to new N-nitrosoamines via the
aminomethylation of heterocyclic NH acids followed by
N,N-Bis[(isatin-1-yl)methyl]methylamine (2a). A mixture
of isatin 1a (1.47 g, 10 mmol), Pr OH (12 mL), and 34%
i

1
636
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001
Korepin et al.
Table 4. Selected geometrical parameters of compound 7b
Bond
d/Å
Bond
d/Å
Bond
d/Å
O(1)—N(1)
N(2)—C(2)
N(3)—C(3)
C(3)—C(4)
C(5)—C(6)
1.231(3) N(1)—N(2)
1.450(3) N(3)—N(4)
1.361(3) N(4)—N (5)
1.393(3) C(3)—C(8)
1.393(4) C(6)—C(7)
1.309(3)
1.368(3) N(3)—C(2)
1.296(3) N(5)—C(8)
1.391(2) C(4)—C(5)
1.356(5) C(7)—C(8)
N(2)—C(1)
1.441(4)
1.440(3)
1.367(3)
1.365(4)
1.402(4)
Angle
ω/deg
Angle
ω/deg
O(1)—N(1)—N(2)
N(1)—N(2)—C(2)
N(4)—N(3)—C(2)
C(2)—N(3)—C(3)
N(4)—N(5)—C(8)
N(3)—Ñ(3)—C(4)
C(4)—Ñ(3)—C(8)
C(4)—Ñ(5)—C(6)
C(5)—Ñ(4)—C(8)
N(5)—C(8)—C(7)
114.3(2)
115.3(2)
120.1(2)
129.5(2)
109.4(2)
133.5(2)
122.5(2)
122.3(3)
116.8(2)
131.3(2)
N(1)—N(2)—C(1)
C(1)—N(2)—C(2)
N(4)—N(3)—C(3)
N(3)—N(4)—N(5)
N(2)—C(2)—N(3)
N(3)—Ñ(3)—C(8)
C(3)—Ñ(4)—C(5)
C(5)—Ñ(4)—C(7)
N(5)—C(8)—C(3)
C(3)—Ñ(8)—C(7)
123.1(2)
121.6(2)
110.4(2)
107.8(2)
111.3(2)
104.0(2)
115.7(2)
122.3(3)
108.4(2)
120.3(2)
formalin (0.88 g, 10 mmol of CH O) was stirred at 70 °C for
yield of 3 was 1.85 g (77%), m.p. 80—82 °C. After recrystalliza-
2
i
2
h. Then a mixture of a 25.9% aqueous solution of MeNH
tion from Pr OH—water, m.p. 83—84 °C.
2
i
(
0.6 g, 5 mmol) and Pr OH (12 mL) was added dropwise over
1,5-Bis(isatin-1-yl)-2,4-dimethyl-2,4-diazapentane (4a). A
3
0 min. The reaction mixture was stirred at 70 °C for 30 min
mixture of a 25.9% aqueous solution of MeNH (3 g, 25 mmol),
2
i
and without heating for 1 h and left overnight. The precipitate
that formed was filtered off, washed with Pr OH and MeOH,
Pr OH (30 mL), formalin (3.5 g, 40 mmol of CH O), and isatin
2
i
(1a) (2.94 g, 20 mmol) was stirred at 50 °C for 1.5 h. After
45 min, an aqueous solution of MeNH2 (0.5 g, 4 mmol) was
added, and the reaction mixture was left without stirring at
∼20 °C overnight. The precipitate that formed was filtered off,
washed with MeOH, and dried. The yield of crude diamine 4a
was 3.3 g (84%), m.p. 168—172 °C (decomp.). This product
was used for subsequent reactions without additional purifica-
tion. An analytical sample (m.p. 174—176 °C, decomp.) was
obtained as described for 2a (20 mL of the solvent per gram,
stirring for 6 h).
and dried. The yield of the crude product was 0.9 g (51.6%),
m.p. 173—176 °C (decomp.). This product was used for subse-
quent reactions without additional purification. An analytical
sample (m.p. 180—182 °C, decomp.) was obtained by stirring
the product in a mixture of MeOH with MeCN (1 : 1, 6 mL of
the mixture per gram) at ∼20 °C for 1 h. The solid precipitate
was filtered off, washed with MeOH, and dried.
N,N-Bis[(benzotriazol-1-yl)methyl]methylamine (2b).
A
2
5.9% aqueous solution of MeNH2 (3 g, 25 mmol) was added
with stirring to a solution of benzotriazole (1b) (5.95 g, 50 mmol)
in 20 mL of Pr OH. Then a solution of formalin (4.5 g,
1,5-Bis(benzotriazol-1-yl)-2,4-dimethyl-2,4-diazapentane
(4b). A mixture of a 25.9% aqueous solution of MeNH (6.6 g,
2
i
i
5
1 mmol of CH O) in 10 mL of water was added dropwise. The
55 mmol), Pr OH (8 mL), formalin (2.2 g, 25 mmol of CH O),
2
2
reaction mixture was stirred at ∼20 °C for 4 h, and water
10 mL) was added dropwise. The resulting solution was stirred
and benzotriazole (1b) (1.19 g, 10 mmol) was stirred at ∼20 °C
for 4 h and then poured onto a watch glass. The solvent was
evaporated with a flow of air with periodical stirring. The solid
residue (1.7 g, theoretical yield 1.68 g) was mixed with 50%
aqueous acetone (2 mL) and cooled to –15 °C. The precipitate
was filtered off and dried. The yield of 4b was 1.43 g (85%),
m.p. 102—105 °C. After recrystallization from MeCN, m.p.
106—108 °C. A mixture of the product with monoamine 2b
clearly depressed the melting point (83—92 °C).
(
for 1 h and left without stirring overnight. The precipitate that
i
formed was filtered off, washed with Pr OH—water (1 : 1), and
dried. The yield of 2b was 6 g (82%), m.p. 96—99 °C. After
recrystallization from acetone, m.p. 101—103 °C (cf. Ref. 13:
m.p. 88—90 °C).
N,N-Bis(succinimidomethyl)methylamine (2c). A 25.9%
aqueous solution of MeNH2 (1.31 g, 11 mmol) was added with
stirring to a mixture of succinimide 1c (1.98 g, 20 mmol) and
1,3-Bis[(isatin-1-yl)methyl]imidazolidine (5a). A mixture
i
Pr OH (7 mL). After 10 min, formalin (1.85 g, 21 mmol of
of a 70% aqueous solution of ethylenediamine (2.57 g, 30 mmol),
i
CH O) was added, and the reaction mixture was stirred for 4 h
Pr OH (45 mL), formalin (8.4 g, 95 mmol of CH O), and isatin
2
2
and cooled to 10 °C. The precipitate that formed was filtered
(1a) (8.82 g, 60 mmol) was stirred at 20 °C for 30 min and then
at 50—55 °C for an additional 2.5 h. The reaction mixture was
left without stirring at ∼20 °C overnight. The precipitate that
i
off, washed with cold Pr OH (–15 °C), and dried. The yield of
2
c was 2.05 g (81%), m.p. 173—177 °C. After recrystallization
i
from CHCl —CCl , m.p. 175—177 °C.
formed was filtered off, washed with Pr OH and MeOH, and
3
4
N-(Succinimidomethyl)diisobutylamine (3). Formalin
dried. The yield of 5a was 11.5 g (98%), m.p. 163—164 °C
(decomp.). The product was used for subsequent reactions
without additional purification. An analytical sample (m.p.
166—167 °C, decomp.) was obtained as described for 4a.
(
(
0.97 g, 11 mmol of CH O), diisobutylamine hydrochloride
1.82 g, 11 mmol), and succinimide (1c) (0.99 g, 10 mmol)
2
were added with stirring to a solution of KHCO3 (1.1 g,
1
5
1 mmol) in 15 mL of water. The reaction mixture was kept at
0 °C for 0.5 h and then cooled to 10 °C. The precipitate that
1,3-Bis[(benzotriazol-1-yl)methyl]imidazolidine (5b). A
i
mixture of benzotriazole (1b) (9.52 g, 80 mmol), Pr OH (68 mL),
formed was filtered off, washed with cold water, and dried. The
a 70% aqueous solution of ethylenediamine (3.43 g, 40 mmol),

Nitrosative cleavage of the Mannich bases
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001 1637
yield of 7b was 1.23 g (56%), m.p. 96—98 °C. After recrystalli-
and formalin (11.12 g, 126 mmol of CH O) was stirred at 20 °C
2
i
for 30 min and then at 50—55 °C for an additional 1 h. The
reaction mixture was cooled to 20 °C, and the precipitate that
zation from CCl4 or Pr OH—n-heptane, m.p. 99—100 °C.
B. The same procedure was used to obtain 7b from com-
pound 4b (3.36 g, 10 mmol), AcOH (20 mL), Ac O (15 mL),
i
formed was filtered off, washed with Pr OH, and dried. The
2
yield of 5b was 11.7 g (87.4%), m.p. 125—127 °C. After
and NaNO (6.9 g), but the crude product was not treated with
2
i
recrystallization from CCl —CHCl , its melting point remained
Pr OH. The yield of 7b was 1.88 g (49%), m.p. 95—98 °C. After
4
3
i
unchanged.
,3-Bis(succinimidomethyl)imidazolidine (5c). A mixture of
recrystallization from CCl4 or Pr OH—n-heptane, m.p.
1
99—100 °C.
a 70% aqueous solution of ethylenediamine (2.14 g, 25 mmol),
The 1H NMR and IR spectra of both samples are identical.
N-Nitroso-N-(succinimidomethyl)methylamine (7c). Sodium
nitrite (2.9 g, 42 mmol) was added portionwise over 1.5 h with
stirring and cooling to 15—18 °C to a mixture of amine 2c
(1.52 g, 6 mmol) and glacial AcOH (22 mL). The reaction
mixture was kept at 15 °C for 6 h and poured into 140 mL of
cold water. The product was extracted with CH Cl . The
i
Pr OH (50 mL), formalin (7.15 g, 81 mmol of CH O), and
2
succinimide (1c) (4.95 g, 50 mmol) was stirred at ∼20 °C for
6
h and left without stirring overnight. The reaction mixture
was then cooled to –15 °C and kept for 6 h. The precipitate
i
that formed was filtered off, washed with cold Pr OH (–15 °C),
and dried. The yield of 5c was 5.7 g (77.5%), m.p. 120—122 °C.
After recrystallization from AcOEt, its melting point remained
unchanged.
2
2
extract was washed with water and dried with MgSO . The
4
solvent was removed in vacuo to give compound 7c (0.92 g,
89.7%), m.p. 79—83 °C. After recrystallization from AcOEt,
m.p. 85—86 °C.
3
-[(Isatin-1-yl)methyl]tetrahydro-1,3-oxazine (6a). A mix-
i
ture of 1a (2.94 g, 20 mmol), Pr OH (29 mL), 3-aminopropan-
-ol (1.5 g, 20 mmol), and formalin (3.53 g, 40 mmol of
1
1,6-Bis(isatin-1-yl)-2,5-dinitroso-2,5-diazahexane (8a) was
obtained as described for 7a from imidazolidine 5a (0.98 g,
2.5 mmol), AcOH (10 mL), and NaNO2 (1.73 g). The yield of
8a was 0.94 g (86%), decomp. at 251—260 °C. After recrystal-
lization from DMSO, decomp. at 262—267 °C.
CH O) was stirred at 50 °C for 1 h. Then the reaction mixture
2
was cooled to 15 °C, and the precipitate that formed was
filtered off and dried. The yield of 6a was 3.9 g (79%),
m.p. 128—130 °C. After recrystallization from CCl , m.p.
4
1
30—132 °C.
1,6-Bis(benzotriazol-1-yl)-2,5-dinitroso-2,5-diazahexane
3
-[(Benzotriazol-1-yl)methyl]tetrahydro-1,3-oxazine (6b)
(8b) was synthesized as described for 7b from imidazolidine 5b
was obtained analogously from compound 1b (11.9 g, 100 mmol).
The yield of 6b was 18.5 g (85%), m.p. 105—107 °C. The
product recrystallized from water has the same melting point.
(3.34 g, 10 mmol), glacial AcOH (17 mL), Ac O (10 mL), and
NaNO2 (4.5 g). The reaction mixture was poured into cold
2
water and left at 0 °C overnight. The product obtained was
i
3
-(Succinimidomethyl)tetrahydro-1,3-oxazine (6c). A mix-
filtered off, dried, mixed with Pr OH (2 mL) and dichloroethane
i
ture of 1c (14.85 g, 150 mmol), Pr OH (45 mL), 3-amino-
(2 mL), heated to boiling, and cooled to ∼20 °C. The precipi-
tate was filtered off and dried. The yield of 8b was 0.4 g
(10.5%), m.p. 150—154 °C. After repeated recrystallization
propanol (11.25 g, 150 mmol), and formalin (26.5 g, 300 mmol
of CH O) was stirred at 50 °C for 1 h. The solvent was removed
2
i
i
in vacuo, and Pr OH (30 mL) and n-heptane (30 mL) were
from Pr OH—dichloroethane, m.p. 162—164 °C.
added to the residue. The mixture was stirred and cooled to
2,5-Dinitroso-1,6-bissuccinimido-2,5-diazahexane (8c) was
obtained as described for 7a from imidazolidine 5c (1.47 g,
5 mmol), glacial AcOH (15 mL), and NaNO2 (3.52 g). The
yield of 8c was 1.36 g (80%), m.p. 228—230 °C (decomp.).
After recrystallization from DMF—DMSO, m.p. 230—231 °C
(decomp.).
0
°C, the precipitate was filtered off and dried. The yield of 6c
was 22.5 g (76%), m.p. 58—60 °C. After recrystallization from
Pr OH—n-heptane, m.p. 64—66 °C.
i
N-[(Isatin-1-yl)methyl]-N-nitrosomethylamine (7a). A. So-
dium nitrite (1.72 g, 25 mmol) was added portionwise over
1
.5 h with stirring and cooling to 15—18 °C to a mixture of
amine 2a (1.05 g, 3 mmol) and glacial AcOH (10 mL). The
reaction mixture was kept at ∼20 °C for 6 h and poured into
Table 5. Crystallographic parameters of the compounds studied
7
0 mL of cold water. The precipitate was filtered off, washed
with water, and dried. The yield of 7a was 0.59 g (90%), m.p.
Parameter
7à
7b
C H N O
1
1
67—170 °C. After recrystallization from CHCl —CCl , m.p.
3 4
71—173 °C.
B. The above procedure was used to obtain compound 7a
Molecular formula
Space group
à/Å
b/Å
ñ/Å
C10H N O
9
Ðñ
3
3
8
9
5
Ð2 /ñ
1
from diamine 4a (0.98 g, 2.5 mmol), AcOH (15 mL), and
NaNO2 (2.59 g). The yield of 7a was 0.94 g (86%), m.p.
10.829 (2)
8.206 (2)
11.705 (2)
96.29
1033.8 (5)
4*
10.832 (2)
8.057 (2)
10.743 (2)
95.36
933.5 (4)
4
1
1
66—169 °C. After recrystallization from CHCl —CCl , m.p.
3 4
71—173 °C.
β/deg
The IR and 1H NMR spectra of both samples are identical.
N-[(Benzotriazol-1-yl)methyl]-N-nitrosomethylamine (7b).
3
V/Å
Z
A. Sodium nitrite (1.38 g, 20 mmol) was added portionwise
over 10 min with stirring and cooling to 0—2 °C to a mixture of
ρcalc/g cm–3
1.408
3—55
1.360
2—56
Scan range θ—2θ/deg
Number of
glacial AcOH (10 mL) and Ac O (10 mL). Then a finely
2
ground mixture of amine 2b (3.37 g, 11.5 mmol) and NaNO2
measured reflections
Number of reflections
with I > 4 σ
2147
3090
(
3.45 g, 50 mmol) was added over 1.5 h. The reaction mixture
was kept at 0—2 °C for 6 h (after 3 h, the thickened mass was
diluted with 7 mL of AcOH), poured into 140 mL of water with
ice, and stirred for 30 min. The precipitate was filtered off,
washed with cold water, and dried. Isopropyl alcohol (2 mL)
was added, and the resulting mixture was thoroughly stirred and
cooled to –15 °C. The solid precipitate was filtered off, washed
1693
2944
Weighting scheme,
w–1
σ2(F )+0.0010F2
σ2(F )+0.041F2
R
0.068
0.079
0.051
0.074
Rw
i
with a small amount of cold Pr OH (–15 °C), and dried. The
* The cell contains two independent molecules.

1
638
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001
Korepin et al.
Synthesis of compound 9. Nitrosative cleavage of amine 3
1.32 g, 5.5 mmol) using glacial AcOH (13 mL) and NaNO2
2. A. Geuther, Lieb. Ann., 1863, 128, 153.
3. E. Fischer, Ber., 1879, 8, 1587.
(
(
2.5 g) was carried out as described for 7a. The reaction
4. V. A. Solonina, Zh. Ros. Fiz.-Khim. O-va [Journal of the
Russian Physicochemical Society], 1906, 38, 1286 (in
Russian).
mixture was poured into 70 mL of cold water, and the product
was extracted with CH Cl . The extract was washed with water
2
2
and dried with MgSO . The solvent was removed, and the
residue was distilled to give compound 9 (0.67 g, 80%), b.p.
5. V. G. Yashunskii and V. F. Vasil´eva, Zh. Obshch. Khim.,
1960, 30, 2754 [J. Gen. Chem. USSR, 1960, 30 (Engl.
Transl.)].
6. M. Ya. Pormalo, E. A. Plisko, and S. D. Danilov, Zh. Org.
Khim., 1965, 1, 1758 [J. Org. Chem., 1965, 1, (Engl.
Transl.)].
7. R. G. Gafurov, E. M. Sogomonyan, and L. T. Eremenko,
Izv. Akad. Nauk SSSR, Ser. Khim., 1971, 20, 2606
[Bull. Acad. Sci. USSR, Div. Chem. Sci., 1971, 20 (Engl.
Transl.)].
8. G. Hein, J. Chem. Educ., 1963, 40, 181.
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14. A. G. Korepin, P. V. Galkin, N. M. Glushakova, V. G.
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4
8
2
6—88 °C (10 Torr), nD20 1.4439. IR, ν/cm–1: 2965, 2935,
900, 2875, 1435, 1390, 1370, 1345 (CH , CH ); 1465, 1070
3
2
(
N—N=O); 1295, 1200 (C—N).
X-ray diffraction analysis. Single crystals of compounds
a,b were stuck to a glass rod with fast-drying epoxy resin and
7
transferred to a diffractometer goniometer. Experimental sets of
reflections were collected on CAD-4 (7a) and Siemens
R3/PC (7b) four-circle automated diffractometers (λ(Mo-Kα),
λ = 0.71074 Å, T = 22 °C). The unit cell parameters were
determined and refined from 24 equivalent reflections with
2
θ < 24—28°. Three strong reflections with 0 < χ < 65° were
measured as standards after every 100 reflections. Because the
intensities of these reflections remained unchanged during data
collection, no special corrections were applied. Crystallographic
parameters and structure refinements are presented in Table 5.
Structures 7a,b were solved by the direct methods and
refined in the full-matrix anisotropic approximation for all
non-hydrogen atoms. Hydrogen atoms were located from a
difference Fourier synthesis and refined isotropically. All calcu-
lations were performed using the SHELXTL PLUS program
package (PC version).20 The atomic coordinates in 7a,b have
been deposited with the Cambridge Crystallographic Database.
Selected geometrical parameters of the molecules studied are
given in Tables 3 and 4.
15. J. Brühl, Z. phys. Chem., 1895, 16, 218.
16. V. A. Solonina, Zh. Ros. Fiz.-Khim. O-va [Journal of
the Russian Physicochemical Society], 1899, 30, 450 (in
Russian).
7. J. Licari, L. Harizel, G. Dougherty, and F. Benson, J. Am.
Chem. Soc., 1955, 77, 5386.
The authors are grateful to G. V. Lagodzinskaya and
M. V. Loginova for recording and analyzing the NMR
spectra.
This work was financially supported by the Interna-
tional Scientific and Technical Center (Project No.
1
1
1
8. C. Kennard, E. O´Reily, and G. Smith, Polyhedron,
1
984, 3, 689.
9. S. E. Nefedov, A. A. Sidorov, H. Berke, and I. L. Eremenko,
Izv. Akad. Nauk SSSR, Ser. Khim., 1988, 1030 [Bull. Acad.
Sci. USSR, Div. Chem. Sci., 1988, 37 (Engl. Transl.)].
0. G. Sheldrick, in Crystallographic Computering 3: Data Col-
lection, Structure Determination, Proteins and Databases,
New York, 1985, 175.
1
23-94).
2
References
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. A. L. Fridman, F. M. Mukhametshin, and S. S. Novikov,
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Received January 22, 2001;
in revised form May 24, 2001