Cubane derivatives 10. Synthesis and molecular structures of nitroxymethylcubanes

Article abstract of DOI:10.1007/s11172-010-0204-2

The reactions of hydroxymethylcubanes with nitric acid result in the respective nitroxymethylcubanes.

Full text of DOI:10.1007/s11172-010-0204-2

Russian Chemical Bulletin, International Edition, Vol. 59, No. 5, pp. 1051—1055, May, 2010
1051
Cubane derivatives
10*. Synthesis and molecular structures of nitroxymethylcubanes
L. B. Romanova,a L. S. Barinova,a V. V. Zakharov,a
L. T. Eremenko†, G. G. Aleksandrov,b and I. L. Eremenkob
aInstitute of Problems of Chemical Physics, Russian Academy of Sciences,
142432 Chernogolovka, Moscow Region, Russian Federation.
Fax: +7 (496) 515 3588. Eꢀmail: lbr@icp.ac.ru
bN. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
31 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (495) 952 1279. Eꢀmail: ilerem@igic.ras.ru
The reactions of hydroxymethylcubanes with nitric acid result in the respective nitroxyꢀ
methylcubanes.
Key words: cubane derivatives, nitroxymethylcubanes, nitroesters, Xꢀray diffraction
analysis, cardiac pharmacological activity, nitric acid.
The search for the drugs to treat cardiovascular and
oncological diseases is currently highly topical. The prepaꢀ
ration of new polyfunctional compounds, study of their
structures and properties will allow expansion of the specꢀ
trum of exogenous NO donors as potential drugs.
Nitrates (or nitroesters) are a wellꢀknown class of orꢀ
ganic substances the pharmacological activity of which is
determined by their metabolism with NO liberation (see
Ref. 2). They include such compounds as Nitroglycerin,
Nitrosorbide, Erinite, and others, which are commonly
used to treat ischemic cardiovascular diseases, for exꢀ
ample, stenocardia. It is known that cubane derivatives
also show rather high antiꢀischemic activity.3,4
With the aim of search for new antiꢀischemic drugs,
we performed the synthesis of nitroesters of the cubane
series.
Previously,5,6 it has been shown that the reduction
of dimethyl cubaneꢀ1,4ꢀdicarboxylate (1a) and methyl
4ꢀbromocubaneꢀ1ꢀcarboxylate (2) afforded 1,4ꢀbisꢀ
(hydroxymethyl)cubane (3) and 4ꢀbromoꢀ1ꢀhydroxyꢀ
methylcubane (4). In the present work, 1,4ꢀbis(nitroxyꢀ
methyl)cubane (5) and 4ꢀbromoꢀ1ꢀnitroxymethylcubane
* For Part 9, see Ref. 1.
†
Deceased.
Scheme 1
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1026—1030, May, 2010.
1066ꢀ5285/10/5905ꢀ1051 © 2010 Springer Science+Business Media, Inc.

1052
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 5, May, 2010
Romanova et al.
(6) (Scheme 1) were synthesized for the first time and
characterized.
The presence of substitutents in positions 1 and 4 of
the cubane fragments practically does not affect their
geometry, in all four structures it is virtually identical.
Molecule 5 (see Fig. 1) has 2/m symmetry, in other comꢀ
pounds (see Fig. 2—5) the molecules are located in
general position. In the strucrute of 8 (see Fig. 3), the
The presence of different pharmacophoric groups in a
molecule is valuable as regards the biological activity.2,7,8
Therefore, the preparation of cubane derivatives bearing
both nitroxymethyl and nitroxyethylamide moiety was of
great interest. The antiꢀischemic activity of the nitroxyꢀ
ethylamide group has been demonstrated by us previꢀ
ously.3,4
The reduction of 4ꢀmethoxycarbonylcubaneꢀ1ꢀcarꢀ
boxylic acid (1b) with sodium borohydride led to 4ꢀhydroxyꢀ
methylcubaneꢀ1ꢀcarboxylic acid (7) in 88—90% yield,
the nitration of that resulted in 4ꢀnitroxymethylcubaneꢀ
1ꢀcarboxylic acid (8) (Scheme 2). The choice of a nitraꢀ
tion system and reaction conditions was problematic due
to intermolecular hydrogen bonds in compound 7 caused
by the presence of the carboxylic groups. Good yield
of compound 8 (93%) was achieved in the reaction perꢀ
formed at –20 °C with the use of 90—95% nitric acid.
Coupling of methyl 4ꢀnitroxymethylcubaneꢀ1ꢀcarboxyꢀ
late (9) with aminoethanol afforded Nꢀ(2ꢀhydroxyethyl)ꢀ
4ꢀnitroxymethylcubaneꢀ1ꢀcarboxamide (10), subsequent
nitration of which with 90—95% nitric acid at –10÷–15 °C
resulted in the target Nꢀ(2ꢀnitroxyethyl)ꢀ4ꢀnitroxyꢀ
methylcubaneꢀ1ꢀcarboxamide (11) in 85—90% yield (see
Scheme 2).
C(2)
C(3)
C(3)
C(1)
O(3)
O(2)
C(4)
O(1)
C(1)
C(3)
N(1)
C(4)
C(3)
C(2)
Fig. 1. The structure of compound 5.
O(3)
N(1)
O(2)
C(6)
C(4)
O(1)
C(9)
Br(1)
C(5)
C(8)
C(1)
C(2)
C(3)
C(7)
Fig. 2. The structure of compound 6.
The structures of the new compounds were established
by elemental analysis, IR and NMR spectroscopy and by
Xꢀray diiffraction analysis (compounds 5, 6, and 8).
O(5)
N(1)
O(4)
C(7)
C(6)
C(8)
C(2)
O(2)
C(1)
O(3)
C(9)
C(5)
C(3)
C(10)
Scheme 2
O(1)
C(4)
Fig. 3. The structure of compound 8.
C(8)
C(2)
O(5)
N(1)
O(2)
C(1)
C(6)
C(7)
O(3)
C(9)
C(10)
C(3)
O(1)
O(4)
C(4)
Fig. 4. Нꢀbonded dimers in structure 8.
O(7)
N(3)
O(5)
C(6)
C(5)
O(2A)
O(6)
C(1)
N(2)
C(12)
C(7)
O(2)
C(11)
N(1)
C(8)
C(4)
C(2)
C(9)
O(1)
C(3)
C(10)
Fig. 5. The structure of compound 11.

Nitroxymethylcubanes
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 5, May, 2010
1053
Table 1. Elemental analysis data of nitroxymethylcubanes 5—11
molecules are linked to each other by strong intermolecuꢀ
lar hydrogen bonds (O(1)—H...O(2), angle 167°, O...O
2.671(5) Å, H...O 1.76(3) Å) with formation of centrosymꢀ
metric dimers (see Fig. 4). In molecule 11 (see Fig. 5),
the disordered nitro group N(2)O(3) is linked with the
atom C(11) and occupies two equivalent positions with
~0.5 population for the O atoms (O(2)—O(4); O(2а)—O(4a)),
and the orientation of these positions is characterized by
the torsion angles N(2)—O(2A)—C(11)—C(10) 107.8(12)°;
N(2)—O(2)—C(11)—C(10) 168.4(7)°.
Compounds 5, 6, and 11 were investigated for antiꢀ
ischemic activity at the National Research Center for the
Safety of Biologically Active Compounds (NRC BAC)
and showed significant coronaryꢀdilatatory activity. The
activity of compound 5 appeared to be equal to that of the
wellꢀknown cardioprotective drug nicorandil, compound
6 was 2 times as potent as nicorandil, and compound 11
was 5 times as potent as nicorandil.
Comꢀ
pound
Molecular
formula
Found
Calculated
(%)
C
H
N
Br
—
5
С10Н10N2О6
С9Н8О3BrN
С10Н10О3
47.13
47.25
41.93
40.80
66.90
67.41
52.75
53.82
55.40
55.70
54.40
54.13
3.80
3.97
3.27
3.12
5.75
5.66
3.97
4.06
4.60
4.67
5.10
5.30
4.10
4.21
11.00
11.02
5.60
5.43
0—
6
31.77
30.96
—
7
8
С10Н9NО5
C11H11NO5
C12H14N2O5
6.10
6.28
5.90
—
—
—
—
9
5.90
10
11
10.50
10.52
13.56
13.50
C12H13 N3O7 47.00
46.31
Experimental
1,4ꢀBis(nitroxymethyl)cubane (5). 1,4ꢀBis(hydroxymethyl)ꢀ
cubane (3) (1 g, 6 mmol) was slowly added to a cooled (0 °С)
mixture of 99% HNO3 (3.8 g, 60 mmol) and Ac2O (6.1 g,
60 mmol), and the reaction mixture was stirred at this temꢀ
perature for 30 min. Then it was poured onto crushed ice. The
precipitate was filtered off, washed with cold water and 1%
NaHCO3 until neutral, dried over P2O5, and recrystallized
from CCl4. Yield 1.2 g (80%), m.p. 123—124 °C (decomp.).
1H (200.13 MHz) and 13C (50.3 MHz) NMR spectra were
recorded on a Bruker DPXꢀ200 spectrometer using Me4Si as the
internal standard. IR spectra were recorded on a Specord M 82
spectrometer (KBr pellets).
Compounds 1a,b and 2—4 were prepared according to
decribed methods.4—6,9 The characteristics of the newly prepared
compounds was given in Tables 1 and 2.
Table 2. The spectral characteristics of nitroxymethylcubanes 5—11
Comꢀ
pound
1Н NMR
13С {1H} NMR
(DMSOꢀd6—CCl4), δ
IR, ν/cm–1
Solvent
CD2Cl2
δ (J/Hz)
5
6
3.89 (s, 6 H, CH); 4.61 (s, 4 H,
CH2ONO2)
000000000—
1611, 1279, 1274, 883
(ONO2); 3007, 1325
(СНcub); 2949, 2867,
1377 (СН2)
1624, 1612, 1279, 885
(ONO2); 820 (С—Br);
2999, 2990, 1318 (СНcub);
2946, 2883, 1448 (СН2)
CDCl3
~4.08 (m, 3 H, CHCCH2ONO2,
Aꢀpart AA´A″BB´B″, Δν ≈ 28);
~4.21 (m, 3 H, CHCBr, Bꢀpart
AA´A″BB´B″); 4.65 (s, 2 H,
CH2ONO2); 3.76 (s, 4 H,
72.81 (s, 1 C, CH2ONO2);
63.83 (s, 1 C, CСBr); 54.26
(s, 3 C, CHСBr); 45.83 (s,
3 C, CHСCH2ONO2)*
CH2CCl); 3.79 (s, 6 H, CH)
7
8
DMSOꢀd6—CCl4 3.28 (br.s, C(O)OH); 3.50
(d, 2 H, CH2OH, 3JCH OH ≈ 4.0);
3.76 (m, 3 H, CHCCH22OH,
000000000—
3252, 1000 (ОН); 2569,
2511, 1662, 1306, 1226
(СООН); 2990, 1321
(СНcub); 2914, 2861,
1457 (СН2)
Bꢀpart AA´A″BB´B″, Δν
= 45);
A,B
4.00 (m, 3 H, CHCC(O), Aꢀpart
AA´A″BB´B″); 4.46 (br.t, 1 H,
CH2OH, 3JCH OH ≈ 4.0)
2
DMSOꢀd6—CCl4 ~3.93 (m, 3 H, CHCC(O), Aꢀpart
172.44 (s, 1 C, C(O)); 73.30
(s, 1 C, CH2ONO2); 55.87
(s, 1 C, CCH2ONO2); 53.56
(s, 1 C, CC(O)); 45.89 (s,
3 C, CHCCH2ONO2); 44.15
(s, 3 C, CHCC(O)
2900, 2705, 2596, 1678,
1418, 1222 (СООН);
1629, 1274, 865 (ONO2);
3002, 1315 (СНcub);
AA´A″BB´B″, Δν
≈ 30.0); ~4.08
A,B
(m, 3 H, CHCCH2ONO2, Bꢀpart
AA´A″BB´B″, Δν ≈ 30.0); 4,72
A,B
(s, 2 H, CH2ONO2); ~7.00 (br.s,
1 H, C(O)OH)
2944, 2888, 1456 (СН2)
(to be continued)

1054
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 5, May, 2010
Romanova et al.
Таблица 2 (continued)
Comꢀ
1Н NMR
13С {1H} NMR
IR, ν/cm–1
pound
(DMSOꢀd6—CCl4), δ
Solvent
δ (J/Hz)
9
DMSOꢀd6—CCl4 3.62 (s, 3 H, OCH3); 4.03 (m, 6 H,
CH, AA´A″BB´B″, Δν ≈ 37.0);
~170 (s, 1 C, C(O)); 73.13
(s, 1 C, CH2ONO2); 65.36
(s, 1 C, CCH2ONO2); 53.53
(s, 1 C, CC(O)); 51.06 (s,
1 C, OCH3); 45.91 (s, 3 C,
CHCCH2ONO2); 44.49
(s, 3 C, CHCC(O))
1716, 1209, 1088 [C(O)O];
1618, 1274, 955, 867
(ONO2); 3001, 1328
(СНcub); 2949, 2884, 2849,
1451, 1436 (СН3, СН2)
A,B
4.72 (s, 2 H, CH2ONO2)
10
DMSOꢀd6—CCl4 3.11 (dt, 2 H, NHCH2CH2,
170.63 (s, 1 C, C(O)); 73.41
(s, 1 C, CH2ONO2); 59.82
(s, 1 C, CH2OH); 57.50 (s,
1 C, CCH2ONO2); 53.25 (s,
1 C, CC(O)); 45.85 (s, 3 C,
CHCCH2ONO2); 44.00 (s,
3 C, CHCC(O)); 41.26 (s,
1 C, NCH2)
3380, 1070 (ОН); 3344 pl,
1621, 1534 [C(O)NH];
1630 pl, 1276, 957, 870,
757 (ONO2); 3001, 1325
(СНcub); 2949, 2884, 2848,
1433 (СН2)
3
3JCH CH ≈ JCH NH ≈ 6.0);
2
2
3.39 2(t, 2 H, CH2OH,
3JCH CH2 ≈ 6.0); ~3.87 (m, 3H,
CH, 2Aꢀpart AA´A″BB´B″,
Δν
≈ 37.0); ~4.06 (m, 3H, CH,
A,B
Bꢀpart AA´A″BB´B″, Δν
≈ 37.0);
A,B
~4.59 (br.s, 1 H, OH); 4.71 (s,
2 H, CH2ONO2); 7.61 (br.t, 1 H,
C(O)NH, 3JNHCH2 ≈ 6.0)
11
DMSOꢀd6—CCl4 3.41 (dt, 2 H, NHCH2CH2,
170.29 (s, 1 C, C(O)); 73.37
(s, 1 C, CH2ONO2); 72.01 (s, 3360, 1620, 1522 [C(O)NH];
1630 pl, 1277, 869 (ONO2);
3
3JCH CH ≈ JCH NH ≈ 5.5);
2
2
2
~3.89 (m, 3 H, CHCC(O),
Aꢀpart AA´A″BB´B″,
1 C, CH2ONO2); 57.31 (s,
1 C, CCH2ONO2); 53.34 (s,
1 C, CC(O)); 45.88 (s, 3 C,
CHCCH2ONO2); 44.12 (s,
3 C, CHCC(O)); 35.93 (s,
1 C, NCH2)
3000, 1327 (СНcub); 2944,
2886, 1457, 1417 (СН2)
Δν
≈ 34.0); ~4.06 (m, 3 H,
A,B
CHCCH2ONO2, Bꢀpart
AA´A″BB´B″, Δν ≈ 34.0);
A,B
4.52 (t, 2 H, CH2ONO2,
3JCH CH2 = 5.5); 4.71 (s,
2 H, 2CH2ONO2); 7.99 (br.t,
1 H, C(O)NH, 3JNHCH2 ≈ 5.5)
* Solvent CDCl3.
4ꢀBromoꢀ1ꢀnitroxymethylcubane (6). 4ꢀBromoꢀ1ꢀhydroxyꢀ
methylcubane (4) (2.1 g, 10 mmol) was slowly added to a cooled
(0 °С) mixture of 99% HNO3 (3.2 g, 50 mmol) and Ac2O (5.1 g,
50 mmol), the mixture was stirred at this temperature for
30 min. Then it was poured onto crushed ice. The precipitate
was filtered off, washed with cold water and 1% NaHCO3 until
neutral, dried over P2O5, and recrystallized from methanol.
Yield 2.2 g (87%), m.p. 108—109 °C (decomp.).
4ꢀHydroxymethylcubaneꢀ1ꢀcarboxylic acid (7). A suspension
of 4ꢀmethoxycarbonylcubaneꢀ1ꢀcarboxylic acid (1.02 g, 5 mmol)
(1b) in 15 mL of water was added with stirring over 30 min to a
cooled (0 °С) solution of NaBH4 (0.84 g, 22 mmol) in 18 mL of
water. The reaction mixture was stirred at room temperature for
2 h. The solution was cooled to 0 °С and 3 M HCl (7.0 mL) was
slowly added with stirring. The precipitate was filtered off, washed
with cold water, cold methanol, dried over P2O5, and recrysꢀ
tallized from a mixture methanol—ether. Yield 0.78 g (89%),
m.p. 200—201 °C (decomp.).
Methyl 4ꢀnitroxymethylcubaneꢀ1ꢀcarboxylate (9). Comꢀ
pound 8 (1.1 g, 5 mmol) was treated with SOCl2 (10 mL) for 1 h
at —20 °C. The excess of SOCl2 was evaporated in vacuo.
Methanol (10 mL) was added to the freshly prepared acid
chloride and the mixture was stirred for 2 h at room temperature.
The solvent was evaporated, the solid residue was recrystallized
from CCl4. Yield 1.1 g (94%), m.p. 102—104 °C.
Nꢀ(2ꢀHydroxyethyl)ꢀ4ꢀnitroxymethylcubaneꢀ1ꢀcarboxamide
(10). A mixture of compound 9 (1.2 g, 5 mmol) and monoꢀ
ethanolamine (1.5 g) in methanol (20 mL) was stirred at 50 °C
for 6 h, then the reaction mixture was cooled to room temꢀ
perature, methanol and the excess of monoethnolamine was
evaporated under reduced pressure. The solid residue was recrysꢀ
tallized from ethanol. Yield 1.0 g (73%), m.p. 124—125 °C.
Nꢀ(2ꢀNitroxyethyl)ꢀ4ꢀnitroxymethylcubaneꢀ1ꢀcarboxamide
(11). Compound 10 (0.8 g, 3 mmol) was slowly added to a
cooled (–10 °C) 91% HNO3 (5 mL). The reaction mixture was
stirred at this temperature for 30 min and poured onto crushed
ice. The precipitate was filtered off, washed with cold water and
1% NaHCO3 until neutral, dried, and recrystallized from
CH2Cl2. Yield 0.6 g (64%), m.p. 102.5—103 °C (decomp.).
Xꢀray diffraction study. The experimental Xꢀray diffraction
data for compounds 5 and 8 were collected on an automated
EnrafꢀNonius Cadꢀ4 diffractometer (graphite monochromator,
ωꢀscanning technique), and for compounds 6 and 11 on an
4ꢀNitroxymethylcubaneꢀ1ꢀcarboxylic acid (8). Conpound 7
(1 g, 5.6 mmol) was slowly added to a cooled (–20 °C) 91%
HNO3 (8 mL) and the mixture was stirred at this temperature
for 30 min. Then the reaction mass was poured onto crushed ice.
The precipitate was filtered off, washed with cold water, dried
over P2O5, and recrystallized from dichloroethane. Yield 0.93 g
(93%), m.p. 140 °C (decomp.).

Nitroxymethylcubanes
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 5, May, 2010
1055
Table 3. Crystallographic parameters of compounds 5, 6, 8, 11
Parameter
5
6
8
11
Molecular formula
Molecular weight
Т/К
Crystal system
Space group
a/Å
b/Å
c/Å
C10H8N2O6
252.18
296(2)
Rhombic
Cmca
6.178(3)
10.362(4)
17.307(8)
90
C9H8BrNO3
258.07
110(2)
Monoclinic
P2(1)/n
8.5212(19)
11.462(3)
9.867(2)
90
C10H9NO5
223.18
296(2)
Monoclinic
P2(1)/c
5.9760(10)
9.995(2)
16.517(3)
90
C12H13N3O7
311.25
296(2)
Monoclinic
P2/c
15.9757(12)
5.2872(4)
16.3633(12)
90
α/deg
β/deg
90
90
1107.9(9)
4
1.512
109.846(5)
90
906.5(4)
4
1.891
4.512
100.07(3)
90
971.4(3)
4
1.526
0.125
101.794(2)
90
1352.97(18)
4
γ/deg
V/Å3
Z
dcalc/g cm–3
μ/mm–1
1.528
0.128
0.128
Radiation λ (MoKα)
Number of measured
reflections
0.71073
882
0.71073
4854
0.71073
3086
0.71073
2437
Number of reflections
with I > 2σ(I)
R1
605
1853
1990
1721
0.0483
0.2059
0.0381
0.0954
0.0543
0.2072
0.0584
0.1923
wR2
automated Bruker AXS SMART diffractometer equipped with a
CCD detector (graphite monochromator, ωꢀscanning technique
with a step of 0.3°, exposure time per frame was 30 s) using a
standard procedure.10 The structures of compounds were solved
by direct method and refined by the fullꢀmatrix leastꢀsquares
method with anisotropic displacement parameters for all nonꢀ
hydrogen atoms. The hydrogen atoms were located in the
difference Fourier maps and refined isotropically using the riding
model. The calculations were carried out using the program
package.11,12
4. L. T. Eremenko, L. B. Romanova, M. E. Ivanova, V. S.
Malygina, L. S. Barinova, G. V. Lagodzinskaya, V. P.
Lodygina, I. L. Eremenko, G. G. Aleksandrov, Izv. Akad.
Nauk, Ser. Khim., 2007, 1359 [Russ. Chem. Bull., Int. Ed.,
2007, 56, 1408].
5. V. V. Zakharov, G. P. Bugaeva, M. E. Ivanova, L. B.
Romanova, L. T. Eremenko, S. E. Nefedov, I. L. Eremenko,
Izv. Akad. Nauk, Ser. Khim., 1998, 1387 [Russ. Chem. Bull.
(Engl. Transl.), 1998, 47, 1349].
6. V. V. Zakharov, G. P. Bugaeva, L. S. Barinova, G. V.
Lagodzinskaya, L. B. Romanova, G. G. Aleksandrov, I. L.
Eremenko, L. T. Eremenko, Izv. Akad. Nauk, Ser. Khim.,
2005, 1461 [Russ. Chem. Bull., Int. Ed., 2005, 54, 1505].
7. A. BashirꢀHashemi, S. Iyer, J. Alster, N. Slagg, Chem. Ind.
1995, 14, 551.
The crystallographic parameters and the main refinement
statistics for compounds 5, 6, 8, 11 are given in Table 3.
Authors are grateful to V. P. Lodygina and G. V.
Lagodzinskaya for the help in the confirmation of the
structures.
8. C.ꢀY. Cheng, L.ꢀW. Hsin, Y.ꢀP. Lin, P.L. Tao, T.ꢀT. Jong,
Bioorg. Med. Chem., 1996, 4, 73.
9. P. E. Eaton, N. Nordari, J. Tsanaktsidis, S. P. Upadhyaya,
Synthesis, 1995, 501.
10. SMART (Control) and SAINT (Integration) Software, Version
5.0, Bruker AXS Inc., Madison, WI, 1997.
11. SHELXTL v. 5.10, Structure Determination Software Suite,
Bruker AXS, Madison, Wisconsin, USA, 1998.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 06ꢀ03ꢀ32482).
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Received October 20, 2009;
in revised form March 4, 2010