Heterocyclization of 3-aminocamphor and 3-aminoisoborneol derivatives with cyclic βdiketones and formaldehyde. synthesis of optically active 1, 2, 3, 4-tetrahydroquinoline derivatives with terpene substituents

Article abstract of DOI:10.1007/s10600-012-0261-x

Spirocyclic 1, 2, 3, 4-tetrahydroquinoline derivatives were prepared in quantitative yield by three-component condensation of dimedone or Meldrum's acid with formaldehyde and (1S, 3R, 4S)-1, 7, 7-trimethyl-3- (arylamino)bicyclo[2.2. 1]heptan-2-one or (1S, 2S, 3R, 4S)-1, 7, 7-trimethyl-3-(arylamino)bicyclo[2.2.1] heptan- 2-ol.

Full text of DOI:10.1007/s10600-012-0261-x

Chemistry of Natural Compounds, Vol. 48, No. 3, July, 2012 [Russian original No. 3, May-June, 2012]
HETEROCYCLIZATION OF 3-AMINOCAMPHOR AND
3-AMINOISOBORNEOL DERIVATIVES WITH CYCLIC
ꢀ-DIKETONES AND FORMALDEHYDE. SYNTHESIS
OF OPTICALLY ACTIVE 1,2,3,4-TETRAHYDROQUINOLINE
DERIVATIVES WITH TERPENE SUBSTITUENTS
1
1*
2
A. P. Kadutskii, N. G. Kozlov, L. L. Frolova,
UDC 547.836
2
2
I. N. Alekseev, and A. V. Kuchin
Spirocyclic 1,2,3,4-tetrahydroquinoline derivatives were prepared in quantitative yield by three-component
condensation of dimedone or Meldrum’s acid with formaldehyde and (1S,3R,4S)-1,7,7-trimethyl-3-
(arylamino)bicyclo[2.2.1]heptan-2-one or (1S,2S,3R,4S)-1,7,7-trimethyl-3-(arylamino)bicyclo[2.2.1]heptan-
2-ol.
Keywords: heterocyclization, reductive amination, camphoroquinone, 1,2,3,4-tetrahydroquinoline, regio- and
stereoselectivity.
Heterocyclic compounds of the quinoline series that contain a chiral moiety are widely used in asymmetric synthesis
as intermediates, ligands, and catalysts. However, the quinoline core is an active pharmacophore so that quinoline derivatives,
as a rule, exhibit various biochemical activities. Many of them are used as pharmaceutical drugs [1, 2].
The natural terpene camphor (2-oxo-1,7,7-trimethylbicyclo[2.2.1]heptane) is traditionally one of the most popular
chiral moieties owing to its stability, lack of inversion, and available enantiomerically pure starting materials for introducing
this fragment [3]. Furthermore, the introduction of a compact lipophilic terpene substituent into the structure of known
biologically active compounds in several instances either increased or improved their biological activity [4].
Many synthetic strategies are currently known for producing N-containing heterocycles based on various arylamines
[5–7]. In our opinion, cascade heterocyclization (cyclocondensation) involving aromatic aldehydes, amines, and cyclic
ꢀ-diketones is the most effective method for synthesizing derivatives of benzo[a]acridine, 1,7-phenanthroline, benzo[f]quinoline,
and other condensed azaheterocycles [8–10].
The goal of the present work was to synthesize several 1,2,3,4-tetrahydroquinoline derivatives substituted with the
optically active camphor moiety. We showed earlier that treatment of mono-N-substituted anilines with cyclic ꢀ-diketones in
the presence of formaldehyde formed in one step 1,2,3,4-tetrahydroquinoline derivatives [11, 12]. The substituent on the N
atom of the starting aniline did not change during the reaction and occupied the 1-position in the tetrahydroquinoline core of
the product. We prepared a series of anilines with the optically active camphor substituent on the N atom and used them in
three-component condensation with formaldehyde and dimedone (5,5-dimethylcyclohexan-1,3-dione) or Meldrum’s acid
(2,2-dimethyl-4,6-dioxo-1,3-dioxane).
Anilines substituted by an optically active terpene moiety were synthesized by indirect reductive amination of
enantiomerically pure (–)-camphoroquinone (1) by a series of aromatic amines [13] (Scheme 1). The mixture of amine and
camphoroquinone was refluxed in the presence of a catalytic amount of BF ·Et O with removal of H O. Then the resulting
3
2
2
ketimine was reduced without isolation and purification by sodium triacetoxyborohydride both obtained from the bottle and
prepared in situ.
1) Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 220072, Minsk, Ul.
Surganova, 13, Belarus, e-mail: loc@ifoch.bas-net.by; 2) Institute of Chemistry, Komi Scientific Center, Ural Branch, Russian
Academy of Sciences, 167982, Syktyvkar, Ul. Pervomaiskaya, 48, Russian Federation, fax: (8212) 21 84 77, e-mail:
frolova-ll@chemi.komisc.ru. Translated from Khimiya Prirodnykh Soedinenii, No. 3, May–June, 2012, pp. 367–372. Original
article submitted November 24, 2011.
©
404
0009-3130/12/4803-0404 2012 Springer Science+Business Media, Inc.

C13
C14
C18
C12
C11
C3
C15
C2
C1
C16
C7
O1
C9
C8
C10
C17
C4
N1
O2
C10A
C6
O2
C5
C16A
C6A
C11A
N1A
C5A
C12A
C9A
C1A
C7A
C15A
C18A
C2A
C14A
C4A
C8A
O1A
C13A
C3A
Fig. 1. General view of (1R,3R,4S)-(p-ethoxyphenylamino)-1,7,7-
trimethylbicyclo[2.2.1]heptan-2-one (3c) from an x-ray crystal
structure analysis.
R
R
4'
3'
2'
7
R
1'
4
O
N
NH
5
a
b
c
3
+
1
6
10
O
O
O
NH
2
1
2a - d
A
3a - d
a: R = CH , b: R = OCH , c: R = OC H , d: R = C H
3
3
2
5
6
5
+
a. PhH, H ; b. NaBH(OAc) ; c. NaBH /AcOH
3
4
Scheme 1
The reaction occurred regio- and stereoselectively and formed optically active 3-arylamino camphor derivatives
(3a–d) in yields of 65–85% after crystallization from EtOH. The sterically more accessible carbonyl in the 3-position of the
bicyclic core was exclusively aminated whereas the carbonyl in the 2-position was untouched. If NaBH(OAc) from the bottle
3
was used, the only reaction product was the aminoketone whereas reduction by NaBH(OAc) prepared in situ partially reduced
3
the carbonyl in the 2-position to a hydroxyl. Thus, it was found according to NMR spectroscopy that aminoketone 3b and the
aminoalcohol 8b corresponding to it were formed exclusively with an exo-hydroxyl in a 100:12 ratio. Crystallization of this
mixture from EtOH isolated the pure aminoketone without the alcohol impurity. This was probably related to the significant
difference in their solubilities in EtOH.
–1
IR spectra of 3a–d showed characteristic narrow strong bands in the range 3363–3387 cm that corresponded to
stretching vibrations of a secondary amine. Bands at 1742–1749 corresponded to C=O stretching vibrations; at 1514–1616, to
C=C stretching vibrations in an aromatic ring. IR spectra of 3b and 3c contained bands for C–O–C groups at 1240.
The amine in the products had exclusively the exo-orientation. This was consistent with selective attack of the bulky
3
triacetoxyborohydride anion at intermediate ketimine A from the sterically less hindered side. The exo-substitution of the C
atom in the terpene moiety of all 3a–d was confirmed unambiguously by PMR spectroscopy. The proton geminal to the amine
4
5
appeared as a singlet whereas the proton on C was a doublet (splitting only by H exo). The lack of spin–spin coupling
3
4
3
4
between the H and H protons was only possible where the dihedral angle H–C –C –H was almost 90°. A doublet instead of
3
4
a singlet for the resonance of the C proton and a doublet of doublets instead of a doublet for the resonance of the C proton
should have been observed in the spectrum with endo-substitution. The structure of 3c was established unambiguously by an
x-ray crystal structure analysis (XSA) (Fig. 1). According to the XSA, two crystallographically independent molecules
crystallized in a chiral space group of the monoclinic system. A feature of the crystal packing of this compound was the
formation between molecules of an ordinary intermolecular H-bond and not the H-bonded dimers or polymers that are more
typical for ꢁ-aminocarbonyl compounds. Thus, the NH-donor ability of the second molecule remained unused.
405

The obtained anilines 3a–d were used in a three-component heterocyclization reaction with dimedone (4) or Meldrum’s
acid (5) and formaldehyde. This formed selectively 1,2,3,4-tetrahydroquinoline derivatives (6a–d and 7b) that were substituted
on the N atom by the optically active camphor moiety (Scheme 2).
R
7'
5'
9
8
7
O
9'
X
X
3'
3
3''
N
X
CH O
2
3a - d
5
+
+
O
1''
1'
O
1
O
X
10
5''
4, 5
O
6a - d, 7b
a
4, 6a - d: X = CH ; 5, 7b: X = O
2
R
R
O
NH
OH
N
CH O
4
+
+
2
OH
O
9d
8b, 8d
a: R = CH ; b: R = OCH ; c: R = OC H ; d: R = C H
3
3
2
5
6
5
a. NaBH /i-PrOH
4
Scheme 2
In all instances the reaction occurred with brief refluxing of the reagent mixture in EtOH without a catalyst. Such
synthetic conditions were rather mild and, as a result, did not cause any changes in the terpene part of the molecule. The
3
3
exo-orientation of the C substituent was preserved in the products. The C proton of the camphane moiety appeared as a
singlet in PMR spectra of 6a–d and 7b. As shown above, this indicated unambiguously that it had the endo-orientation.
–1
IR spectra of 6a–d and 7b showed two strong absorption bands for carbonyls at 1697 and 1740 cm and bands at 1502–1610
that were characteristic of C=C bonds of an aromatic ring. Absorption bands of C–O–C groups at 1230–1240 were also
characteristic of 6b, 6c, and 7b.
We used anilines 3b and 3d as examples to show that the camphor ketone could be reduced stereoselectively. The
resulting aminoalcohol (8d) was condensed with dimedone (4) in the presence of formaldehyde. The product of this reaction
was a 1,2,3,4-tetrahydroquinoline (9d) substituted at the N atom by an optically active isobornyl moiety.
The aminoketones (3b and 3d) were reduced by NaBH in i-PrOH at room temperature. The reduction occurred
4
stereoselectively to give 3-exo-arylaminoisoborneols (8b and 8d) as the only products. IR spectra of 8b and 8d lacked C=O
–1
absorption bands and contained a broad absorption band at 3400 cm that was characteristic of a hydroxyl. The 2-exo-3-exo-
3
orientation of the substituents in the compounds was confirmed by the large SSCC ( J = 7.0 Hz, for 2-endo-OH a considerably
2,3
smaller constant would be observed).
Diamine 11 with two camphor moieties was formed by reductive amination of camphoroquinone and
p-phenylenediamine (10) at a 1:10 mole ratio of 2:1. Treatment of 11 with formaldehyde and dimedone caused cyclization
into pyrido[2,3-g]quinoline 12 (Scheme 3). The relative simplicity of the NMR spectra of 11 and 12 and the presence of only
one proton resonance in the aromatic region indicated that the molecule was symmetric.
O
O
NH
2
2
H
N
O
O
N
O
N
O
+
N
H
O
O
NH
O
O
1
10
11
12
Scheme 3
406

Thus, we developed a new two-step synthetic method for optically active 1,2,3,4-tetrahydroquinoline derivatives
with terpene substituents. The method was based on reductive amination of enantiomerically pure (–)-camphoroquinone by a
series of aromatic amines and heterocyclization of the resulting derivatives of 3-aminocamphor and 3-aminoisoborneol.
EXPERIMENTAL
IR spectra were recorded in KBr pellets or as thin layers on Nicolet Protege-460 and IR-Prestige-21 Fourier
spectrophotometers. PMR spectra were taken from solutions in DMSO-d with TMS internal standard on Bruker Avance-II-
6
1
13
1
13
300 (300.17 MHz for H; 75.48 MHz for C) and DRX-500 (500.13 MHz for H; 125.75 MHz for C) spectrometers.
Melting points were determined on a TP melter. Optical rotation angles were measured on a Kruss P3002PS automated
polarimeter. Elemental analysis was performed on an EA 1110 (CHNSO) elemental analyzer. The XSA was carried out on an
Xcalibur-3 x-ray diffractometer with a CCD detector using the standard procedure (ꢂ Mo-Kꢁ, graphite monochromator, ꢃ-
scanning). A data set was collected and processed using the CrysAlis software. Absorption corrections were not applied. The
structures of all compounds were solved by direct methods using the SHELXS-97 program and refined using the SHELXL-97
program [14] and anisotropic (isotropic for H atoms) parameters. H atoms were partially determined and refined independently,
partially including in the refinement a rider model with dependent thermal parameters. According to the XSA the crystal was
°
°
°
monoclinic, P2 , a = 14.119(2) A, b = 7.5590(13) A, c = 15.486(2) A, ꢀ = 96.213(12)°, Z = 4. A total of 7013 reflections were
1
measured. Of these, 3580 were independent (R = 0.0493) and 1580 with I > 2ꢄ(I). The completeness for ꢅ = 26.37° was
int
98.6%. The final refinement parameters were R = 0.0349, wR = 0.0292 for reflections with I > 2ꢄ(I); R = 0.1149,
1
2
1
wR = 0.0334 (over all reflections) for S = 0.864. Silica gel (Lancaster) was used for column chromatography. TLC was
2
performed on Sorbfil plates with detection by I . Optically active (–)-camphoroquinone was prepared by the literature method
2
[15] {[ꢁ] –101.1° (c 1.3, toluene), mp 198–199°C}.
D
General Method for Synthesizing N-Aryl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one-3-exo-amines (3) by
Reductive Amination of (–)-Camphoroquinone (1) by Arylamines (2). Method a): primary arylamine 2 (0.01 mol) and
diketone 1 (0.01 mol) were dissolved in benzene (70 mL), treated with BF ·Et O (5–6 drops), refluxed with a Dean–Stark trap
3
2
for 4–5 h until the theoretical amount of H O was separated, cooled, stirred, treated in portions with NaBH(OAc)
2
3
(0.025 mol), left overnight, and worked up with aqueous NaOH (10%). The benzene layer was separated, washed, and dried
over anhydrous MgSO . The solvent was removed. The resulting oil was crystallized for 30–60 min. The yields of 3a–d were
4
65–87% after recrystallization from EtOH.
Method b): primary arylamine (0.02 mol), diketone 1 (0.02 mol), and HOAc (1 mL) were dissolved in benzene
(250 mL), refluxed with a Dean–Stark trap for 6–12 h until the theoretical amount of H O was separated, cooled, treated in
2
portions with NaBH (3.8 g, 0.1 mol), cooled, treated with glacial HOAc (18 g, 0.3 mol), and refluxed for another 24 h. The
4
benzene was distilled off. The residue was worked up with aqueous NaOH (10%). The separated oil was extracted with Et O.
2
The Et O extract was washed and dried over MgSO . The Et O was removed. The product was crystallized from EtOH.
2
4
2
(1R,3R,4S)-1,7,7-Trimethyl-3-(p-tolylamino)bicyclo[2.2.1]heptan-2-one (3a), C H NO, yield 87%, mp 86–87°C,
17 23
–1
[ꢁ] +64.5° (c 1.0, CHCl ). IR spectrum (ꢆ, cm ): 3375 (NH), 2957, 2924, 2878, 1744 (C=O), 1616, 1587, 1522, 1479,
D
3
1449, 1393, 1346, 1319, 1300, 1263, 1192, 1117, 1022, 947, 822, 804, 702, 552, 515.
PMR spectrum (CDCl , , ppm, J/Hz): 0.97 (3H, s, CH -9), 0.98 (3H, s, CH -8), 1.01 (3H, s, CH -10), 1.62–1.78
3
3
3
3
(3H, m), 2.11 (1H, m), 2.27 (1H, d, J = 4.0, H-4), 2.28 (3H, s, CH -Ar), 3.38 (1H, s, H-3), 6.53 (2H, d, J = 7.4, H-2ꢇ), 7.03 (2H,
3
d, J = 7.4, H-3ꢇ).
13
C NMR spectrum (CDCl , , pm): 9.3 (C-9), 20.4 (C-8), 20.5 (C-10), 20.7 (CH -Ar), 26.2 (C-5), 28.7 (C-6), 46.9
3
3
(C-7), 47.7 (C-4), 56.5 (C-1), 65.3 (C-3), 113.3 (C-2ꢇ), 127.2 (C-4ꢇ), 129.7 (C-3ꢇ), 145.5 (C-1ꢇ), 217.8 (C-2, C=O).
(1R,3R,4S)-(p-Methoxyphenylamino)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (3b), C H NO , yield 85%,
17 23
2
–1
mp 75–76°C, [ꢁ] +58.7° (c 0.8, CHCl ). IR spectrum (ꢆ, cm ): 3377 (NH), 2957, 2874, 2833 (C–H), 1742 (C=O), 1616,
D
3
1514, 1460, 1395, 1350, 1317, 1294, 1240 (C–O–C), 1179, 1147, 1113, 1036, 947, 818, 745, 523.
PMR spectrum (CDCl , , ppm, J/Hz): 0.95 (3H, s, CH -9), 0.96 (3H, s, CH -8), 0.98 (3H, s, CH -10), 1.55–1.80
3
3
3
3
(3H, m), 2.09 (1H, m), 2.23 (1H, d, J = 4.0, H-4), 3.32 (1H, s, H-3), 3.75 (3H, s, CH O-4ꢇ), 6.55 (2H, d, J = 9.0, H-2ꢇ), 6.80
3
(2H, d, J = 9.0, H-3ꢇ).
13
C NMR spectrum (CDCl , , pm): 9.3 (C-9), 20.6 (C-8), 20.8 (C-10), 26.3 (C-6), 28.7 (C-5), 47.1 (C-7), 47.7
3
(C-3), 55.8 (C-4), 56.7 (C-1), 65.8 (CH O), 114.5 (C-2ꢇ), 115.0 (C-3ꢇ), 142.2 (C-4ꢇ), 152.7 (C-1ꢇ), 218.0 (C-2, C=O).
3
407

(1R,3R,4S)-(p-Ethoxyphenylamino)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (3c), C H NO , yield 71%,
18 25
2
–1
mp 87–88°C, [ꢁ] +62.7° (c 0.4, CHCl ). IR spectrum (ꢆ, cm ): 3364 (NH), 2974, 2967, 2928, 2872, 2824, 2799 (C–H),
D
3
1749 (C=O), 1616, 1589, 1514, 1479, 1449, 1393, 1323, 1292, 1246, 1186, 1150, 1117, 1049, 1024, 950, 922, 818, 758, 600,
523.
PMR spectrum (CDCl , , ppm, J/Hz): 0.95 (3H, s, CH ), 0.96 (3H, s, CH ), 0.98 (3H, s, CH ), 1.39 (3H, t, J = 7.0,
3
3
3
3
OCH CH ), 1.60–1.80 (3H, m), 2.09 (1H, m), 2.23 (1H, d, J = 4.0, H-4), 3.32 (1H, s, H-3), 3.97 (2H, q, J = 7.0, OCH CH ),
3
3
2
3
6.54 (2H, d, J = 9.0, H-2ꢇ), 6.80 (2H, d, J = 9.0, H-3ꢇ).
13
C NMR spectrum (CDCl , , pm): 9.3 (C-9), 15.1 (CH CH ), 20.6 (C-8), 20.8 (C-10), 26.3 (C-6), 28.7 (C-5), 47.1
3
3
2
(C-7), 47.7 (C-3), 56.6 (C-4), 64.1 (C-1), 65.8 (CH CH ), 114.4 (C-2ꢇ), 115.9 (C-3ꢇ), 142.2 (C-4ꢇ), 151.9 (C-1ꢇ), 218.1 (C-2,
3
2
C=O).
(1R,3R,4S)-(1ꢇ,1ꢇꢇ-Biphenyl-4ꢇ-ylamino)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (3d), C H NO, yield 65%,
22 25
–1
mp 122–123°C, [ꢁ] +88.1° (c 0.4, CHCl ). IR spectrum (ꢆ, cm ): 3387 (NH), 3028, 2957, 2874, 1746 (C=O), 1611, 1528,
D
3
1489, 1449, 1393, 1371, 1323, 1300, 1285, 1196, 1020, 949, 922, 827, 762, 698, 554, 500.
PMR spectrum (CDCl , , ppm, J/Hz): 1.00 (3H, s, CH -8), 1.01 (3H, s, CH -10), 1.04 (3H, s, CH -9), 1.62–1.83
3
3
3
3
(3H, m), 2.15 (1H, m), 2.33 (1H, d, J = 4.0, H-4), 3.47 (1H, s, H-3), 6,69 (2H, d, J = 9.0, H-3ꢇ), 7.31 (1H, t, J = 7.5), 7.44 (2H,
dd, J = 7.5, 8.0), 7.50 (2H, d, J = 9.0, H-2ꢇ), 7.59 (2H, d, J = 8.0).
13
C NMR spectrum (CDCl , , pm): 9.4 (C-9), 20.7 (C-8), 20.8 (C-10), 26.4 (C-6), 28.7 (C-5), 47.1 (C-7), 47.7
3
(C-4), 56.8 (C-1), 65.0 (C-3), 113.6 (C-3ꢇ), 126.2, 126.4, 128.0, 128.8 (C-2ꢇ), 131.2, 141.3, 147.4, 217.8 (C-2, C=O).
Isolation of (1R,3R,4S)-(p-Methoxyphenylamino)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (3b). The reaction
mixture (0.69 g) obtained from reductive amination of camphoroquinone and 2b in the presence of NaBH(OAc) prepared in
3
situ was purified by column chromatography (silica gel, hexane:Et O, 4:1). The solvent was removed to afford the product as
2
a bright-yellow oil (0.58 g) containing according to TLC (Sorbfil, hexane:Et O, 4:1, detection by I ) two compounds with
2
2
R 0.5 and R 0.3. It was found from NMR spectroscopy that these were aminoketone 3b and aminoalcohol 8b in a 100:12
f
f
ratio. Recrystallization from hot EtOH afforded 3b with R 0.5 as light-yellow fibers. The spectral data agreed with those
f
given above.
General Method for Reduction of 3b and 3d to Aminoalcohols 8b and 8d. A solution of the aminoketone
(0.01 mol) in i-PrOH (20 mL) was stirred, treated over 10 min with NaBH (0.38 g, 0.01 mol) at room temperature and under
4
Ar, stirred for another 19 h, and treated with H O (50 mL). The products were separated by extraction (3ꢈ) with Et O. The
2
2
organic extract was dried over anhydrous MgSO . The solvent was removed. The yields of products were 85–86%.
4
(1R,2S,3R,4S)-(p-Methoxyphenylamino)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol (8b), yield 85%, oil, R 0.4
f
–1
(Sorbfil, hexane:Et O, 3:1, detection by I ). IR spectrum (ꢆ, cm ): 3402 (OH, NH), 2949, 2883, 2831, 1514, 1462, 1392,
2
2
1367, 1238 (C–O), 1143, 1097, 1060, 1037, 819, 779, 520.
PMR spectrum (CDCl , , ppm, J/Hz): 0.71 (3H, s, CH ), 1.0 (3H, s, CH ), 1.15 (3H, s, CH ), 1.51 (1H, m), 1.78 (2H,
3
3
3
3
m), 2.99 (br., OH), 3.3 (1H, d, J = 7.0), 3.70 (1H, d, J = 7.0), 3.77 (3H, s, CH O), 6.60 (2H, d, J = 9.0), 6.80 (2H, d, J = 9.0).
3
13
C NMR spectrum (CDCl , , ppm): 11.47 (C-8), 21.29 (C-9), 21.89 (C-10), 25.49 (C-5), 33.07 (C-6), 46.82 (C-1),
3
49.27 (C-7), 51.35 (C-4), 55.83 (C-1), 64.91 (C-3), 79.92 (C-2), 114.89 (C-2), 115.09 (C-3ꢇ), 142.64 (C-1ꢇ), 152.64 (C-4ꢇ).
(1R,2S,3R,4S)-3-(1ꢇ,1ꢇꢇ-Biphenyl-4ꢇ-ylamino)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol (8d), C H NO, yield 86%,
22 27
–1
mp 125–126°C. IR spectrum (ꢆ, cm ): 3585, 3404 (OH, NH), 2951, 2920, 2880, 1611, 1526, 1485, 1334, 1318, 1185, 1058,
822, 762, 695.
PMR spectrum (CDCl , , ppm, J/Hz): 0.90 (3H, s, CH -9), 1.06 (3H, s, CH -8), 1.21 (3H, s, CH -10), 1.14–1.26
3
3
3
3
(2H, m, H-6), 1.60 (1H, m, H-5), 1.83 (1H, m, H-5), 1.90 (1H, d, J = 4.0, H-4), 2.79 (br., OH), 3.47 (1H, d, J = 7.0, H-3), 3.83
(1H, d, J = 7.0, H-2), 4.19 (v.br., NH), 6.76 (2H, d, J = 8.2), 7.33 (1H, t, J = 6.8), 7.46 (2H, dd, J = 6.8, 7.2), 7.52 (2H, d, J = 8.2),
7.60 (2H, d, J = 7.2).
13
C NMR spectrum (CDCl , , ppm): 11.6 (C-9), 21.3 (C-8), 22.0 (C-10), 26.6 (C-6), 33.2 (C-5), 47.1 (C-7), 49.5
3
(C-1), 50.7 (C-4), 63.4 (C-3, C–N), 80.1 (C-2, C–O), 113.9, 126.3, 126.4, 128.1, 128.8, 131.1, 141.4, 147.7.
General Method for Multi-component Condensation of N-Aryl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-on-3-
exo-amines (3a-d) or N-Aryl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-exo-ol-3-exo-amine (8d), Dimedone or Meldrum’s
Acid, and Formaldehyde. The appropriate amine (0.001 mol) and paraformaldehdye (0.12 g, 0.004 mol) in EtOH (25 mL)
was refluxed until both components dissolved completely (5 min). The resulting solution was treated with dimedone (Meldrum’s
acid) (0.14 g, 0.001 mol), refluxed for another 5 min, and cooled. The resulting precipitate was filtered off and washed with
EtOH (2 ꢈ 5 mL). The mother liquors were left open to air to evaporate most of the solvent. A second crop of product was
filtered off. Yields 86–98%.
408

4ꢇꢇ,4ꢇꢇ,6ꢇ-Trimethyl-1ꢇ-{(1R,3R,4S)-1,7,7-trimethyl-2-oxobicyclo[2.2.1]heptan-3-yl}-2ꢇ,4ꢇ-dihydro-1ꢇH-
spiro[cyclohexane-1ꢇꢇ,3ꢇ-quinoline]-2ꢇꢇ,6ꢇꢇ-dione (6a), C H NO , yield 87%, mp 113–114°C, [ꢁ] +19.9° (c 0.4, CHCl ).
27 35
3
D
3
–1
IR spectrum (ꢆ, cm ): 3402, 2957, 2872, 2830, 2733, 1740, 1697, 1611, 1585, 1508, 1458, 1425, 1373, 1319, 1269, 1250,
1211, 1159, 1086, 1047, 1003, 962, 941, 883, 804, 762, 708, 662, 625, 584, 532, 501.
PMR spectrum (CDCl , , ppm, J/Hz): 0.92 (3H, s, CH -9), 0.93 (3H, s, CH -8), 0.94 (3H, s, CH -10), 1.00 (3H, s,
3
3
3
3
CH ), 1.12 (3H, s, CH ), 1.62 (2H, m), 1.75 (1H, dd, J = 2.6, 4.0), 2.07 (1H, m), 2.26 (3H, s, CH -Ar), 2.29 (1H, d, J = 4.0,
3
3
3
H-4), 2.54 (1H, d, J = 14.3), 2.57 (1H, d, J = 14.3), 2.79 (1H, d, J = 14.5), 3.00 (1H, d, J = 15.5), 3.06 (1H, d, J = 14.5), 3.08
(1H, d, J = 15.5), 3.48 (1H, s, H-3), 3.63 (1H, d, J = 12.0), 3.67 (1H, d, J = 12.0), 6.35 (1H, d, J = 8.2, H-8ꢇ), 6.94 (1H, d,
J = 8.2, H-7ꢇ), 6.96 (1H, s, H-5ꢇ); eight doublets in the range 2.54–3.67, four methylene groups of the spiro-ring.
13
C NMR spectrum (CDCl , , ppm): 9.79 (C-9), 20.45 (C-8), 20.70 (CH -Ar), 21.13 (C-10), 26.67 (C-5), 27.75
3
3
(CH ), 29.50 (CH ), 30.22 (C-6), 30.75 (C-4ꢇ), 30.76 (C-4ꢇꢇ), 46.19 (C-7), 48.53 (C-4), 49.82 (C-2ꢇ), 51.38 (C-4ꢇꢇ), 51.62
3
3
(C-2ꢇ, CH –N), 57.98 (C-1), 66.07 (C-spiro), 68.65 (C-3, CH–N), 113.26 (C-8ꢇ), 124.47 (C-10ꢇ), 127.20 (C-7ꢇ), 128.27 (C-6ꢇ),
2
129.45 (C-5ꢇ), 142.82 (C-9ꢇ), 206.54 (C=O), 206.80 (C=O), 216.88 (C-2, C=O).
4ꢇꢇ,4ꢇꢇ-Dimethyl-6ꢇ-methoxy-1ꢇ-{(1R,3R,4S)-1,7,7-trimethyl-2-oxobicyclo[2.2.1]heptan-3-yl}-2ꢇ,4ꢇ-dihydro-1ꢇH-
spiro[cyclohexane-1ꢇꢇ,3ꢇ-quinoline]-2ꢇꢇ,6ꢇꢇ-dione (6b), C H NO , yield 91%, mp 124–125°C, [ꢁ] +17.1° (c 0.4, CHCl ).
27 35
4
D
3
–1
IR spectrum (ꢆ, cm ): 3410, 2953, 2871, 2825, 2732, 1746, 1687, 1623, 1590, 1501, 1455, 1363, 1311, 1253, 1135, 1090,
1013, 969, 801, 764, 589.
PMR spectrum (CDCl , , ppm, J/Hz): 0.89 (3H, s, CH -9), 0.90 (3H, s, CH -8), 0.91 (3H, s, CH -10), 0.96 (3H, s,
3
3
3
3
CH ), 1.10 (3H, s, CH ), 1.58 (2H, m, H-5), 1.72 (1H, dd, J = 2.5, 4.0, H-6), 2.04 (1H, m, H-6), 2.25 (1H, d, J = 4.0, H-4), 2.48
3
3
(1H, d, J = 14, H-5), 2.52 (1H, d, J = 14, H-5ꢇꢇ), 2.77 (1H, d, J = 15, H-3ꢇꢇ), 3.03 (1H, d, J = 15, H-4ꢇ), 3.08 (1H, d, J = 15,
H-4ꢇ), 3.10 (1H, d, J = 15, H-3ꢇꢇ), 3.36 (1H, s, H-3), 3.54 (1H, d, J = 12, H-2ꢇ), 3.68 (1H, d, J = 12, H-2ꢇ), 3.73 (3H, s,
CH O-6ꢇ), 6.37 (1H, d, J = 8, H-8ꢇ), 6.67 (1H, dd, J = 3.0, 8.0, H-7ꢇ), 6.74 (1H, d, J = 3.0, H-5ꢇ).
3
13
C NMR spectrum (CDCl , , ppm): 6.58 (C-9), 20.46 (C-8), 20.96 (C-10), 26.40 (C-6), 27.35 (C-5), 29.46 (C-5ꢇꢇ),
3
30.00 (CH ), 30.01 (CH ), 30.52 (C-3ꢇꢇ), 45.92 (C-7), 48.32 (C-4ꢇ), 50.46 (C-3), 51.31 (C-4ꢇꢇ), 51.39 (C-2ꢇ), 55.36 (C-4),
3
3
57.73 (C-1), 66.50 (C-spiro), 68.46 (CH –O), 111.40 (C-5ꢇ), 114.45 (C-8ꢇ), 114.52 (C-7ꢇ), 126.58 (C-10ꢇ), 139.23 (C-6ꢇ),
3
152.89 (C-9ꢇ), 206.09 (C=O), 206.23 (C=O), 216.70 (C-2, C=O).
4ꢇꢇ,4ꢇꢇ-Dimethyl-6ꢇ-ethoxy-1ꢇ-{(1R,3R,4S)-1,7,7-trimethyl-2-oxobicyclo[2.2.1]heptan-3-yl}-2ꢇ,4ꢇ-dihydro-1ꢇH-
spiro[cyclohexane-1ꢇꢇ,3ꢇꢇ-quinoline]-2ꢇꢇ,6ꢇꢇ-dione (6c), C H NO , yield 93%, mp 135–136°C, [ꢁ] +18.3° (c 0.4, CHCl ).
28 37
4
D
3
–1
IR spectrum (ꢆ, cm ): 2963, 2930, 2874, 2783, 1742, 1697, 1614, 1584, 1503, 1472, 1443, 1393, 1372, 1331, 1315, 1240,
1179, 1159, 1115, 1049, 1003, 972, 947, 812, 714, 662, 583, 509.
PMR spectrum (CDCl , , ppm, J/Hz): 0.91 (3H, s, CH ), 0.92 (3H, s, CH ), 0.93 (3H, s, CH ), 0.98 (3H, s, CH ),
3
3
3
3
3
1.13 (3H, s, CH ), 1.39 (3H, t, J = 7.0, CH CH ). 1.56–1.64 (2H, m, H-5), 1.74 (1H, dd, J = 10.0, 12.0, H-6), 2.06 (1H,
3
3
2
m, H-6), 2.26 (1H, d, J = 4.2, H-4), 2.51 (1H, d, J = 14.8), 2.54 (1H, d, J = 14.8), 2.79 (1H, d, J = 14.5), 3.03 (1H, d, J = 15.6),
3.05 (1H, d, J = 14.5), 3.09 (1H, d, J = 15.6), 3.39 (1H, s, H-3), 3.56 (1H, d, J = 11.8), 3.70 (1H, d, J = 11.8), 3.98 (2H, q,
CH –O) 6.38 (1H, d, J = 8.8, H-8ꢇ), 6.68 (1H, dd, J = 2.9, 8.8, H-7ꢇ), 6.76 (1H, d, J = 2.9, H-5ꢇ).
2
13
C NMR spectrum (CDCl , , ppm): 9.86 (C-9), 15.16 (CH CH ), 20.73 (C-8), 21.24 (C-10), 26.70 (C-6), 27.63
3
3
2
(CH ), 29.78 (CH ), 30.20 (CH ), 30.27 (CH ), 46.22 (C-7), 48.60 (CH –N), 50.79 (CH ), 51.60 (CH ), 51.70 (CH ), 58.02
3
3
2
2
2
2
2
2
(C-1), 63.86 (CH–N), 66.79 (C-spiro), 68.75 (CH –O), 112.41 (C-5ꢇ), 114.72 (C-8ꢇ), 115.54 (C-7ꢇ), 128.84 (C-10ꢇ), 139.42
2
(C-6ꢇ), 152.53 (C-9ꢇ), 206.44 (C=O), 206.63 (C=O), 217.13 (C-2, C=O).
4ꢇꢇ,4ꢇꢇ-Dimethyl-6ꢇ-phenyl-1ꢇ-{(1R,3R,4S)-1,7,7-trimethyl-2-oxobicyclo[2.2.1]heptan-3-yl}-2ꢇ,4ꢇ-dihydro-1ꢇH-
spiro[cyclohexane-1ꢇꢇ,3ꢇꢇ-quinoline]-2ꢇꢇ,6ꢇꢇ-dione (6d), C H NO , yield 98%, mp 164–165°C, [ꢁ] +14.0° (c 0.1, CHCl ).
32 37
3
D
3
–1
IR spectrum (ꢆ, cm ): 3387, 3028, 2959, 2928, 2872, 1746, 1697, 1609, 1520, 1487, 1454, 1389, 1373, 1321, 1283, 1265,
1204, 1161, 1078, 1020, 959, 947, 895, 827, 808, 762, 696, 629, 584, 530, 503.
PMR spectrum (CDCl , , ppm, J/Hz): 0.96 (3H, s, CH ), 0.97 (3H, s, CH ), 0.98 (3H, s, CH ), 1.04 (3H, s, CH ),
3
3
3
3
3
1.15 (3H, s, CH ), 1.62–1.83 (3H, m), 2.15 (1H, m), 2.38 (1H, d, J = 4.0, H-4), 2.58 (1H, d, J = 14.5), 2.64 (1H, d, J = 14.5),
3
2.81 (1H, d, J = 14.7), 3.13 (1H, d, J = 14.6), 3.13 (1H, d, J = 14.7), 3.20 (1H, d, J = 14.6), 3.61 (1H, d, J = 11.7), 3.60 (1H, s,
H-3), 3.85 (1H, d, J = 11.7), 6.25 (1H, d, J = 9.1), 7.30 (1H, m), 7.41 (4H, m), 7.58 (2H, m).
13
C NMR spectrum (CDCl , , ppm): 9.91 (C-9), 20.87 (C-8), 21.27 (C-10), 26.97 (C-6), 27.96 (CH ), 29.56 (CH ),
3
3
3
30.30 (C-5), 30.91 (C-4ꢇꢇ), 31.48 (CH ), 46.24 (C-7), 48.78 (C-4), 49.47 (CH ), 51.46 (CH ), 51.81 (CH ), 57.95 (C-1), 65.27
2
2
3
2
(C-spiro), 68.88 (C-3, CH–N), 113.83, 124.19, 125.51, 126.38, 126.67 (2C), 127.51, 128.80 (2C), 131.59, 141.11, 144.29,
206.23 (C=O), 206.74 (C=O), 216.44 (C-2, C=O).
409

6ꢇ-Methoxy-4ꢇꢇ,4ꢇꢇ-dimethyl-1ꢇ-{(1R,3R,4S)-1,7,7-trimethyl-2-oxobicyclo[2.2.1]heptan-3-yl}-2ꢇ,4ꢇ-dihydro-1ꢇH-
–1
spiro{[3ꢇꢇ,5ꢇꢇ]dioxane-1ꢇꢇ,3ꢇ-quinoline}-2ꢇꢇ,6ꢇꢇ-dione (7b), C H NO , yield 87%, mp 137°C. IR spectrum (ꢆ, cm ): 3407,
25 31
6
2956, 2925, 1740, 1698, 1651, 1619, 1504, 1454, 1383, 1267, 1207, 1161, 1034, 851, 598.
PMR spectrum (CDCl , , ppm, J/Hz): 0.94 (3H, s, CH ), 0.95 (3H, s, CH ), 0.96 (3H, s, CH ), 1.55 (1H, ddd, H-5),
3
3
3
3
1.63 (1H, ddd, H-5), 1.73 (1H, ddd, H-6), 1.76 (3H, s, CH –C–O), 1.82 (3H, s, CH –C–O), 2.07 (1H, m, H-6), 2.29 (1H, d,
3
3
J = 4.0, H-4), 3.25 (1H, d, J = 15.8, H-4ꢇ), 3.31 (1H, d, J = 15.8, H-4ꢇ), 3.40 (1H, s, H-3), 3.57 (1H, d, J = 12.5, H-2ꢇ), 3.76 (3H,
s, CH O-6ꢇ), 3.97 (1H, d, J = 12.5, H-2ꢇ), 6.57 (1H, d, J = 8.8, H-8ꢇ), 6.70 (1H, d, J = 2.9, H-5ꢇ), 6.78 (1H, dd, J = 2.9, 8.8, H-7ꢇ).
3
13
C NMR spectrum (CDCl , , ppm): 9.78 (C-9), 20.65 (C-8), 21.10 (C-10), 26.36 (C-6), 28.93 (CH ), 29.50 (CH ),
3
3
3
30.14 (C-5), 35.15 (C-4ꢇ), 46.49 (C-7), 49.21 (C-4ꢇꢇ), 49.58 (C-3), 52.84 (C-2ꢇ), 55.68 (C-4), 57.88 (C-1), 69.81 (CH O-6ꢇ),
3
105.38 (C-spiro), 112.60 (C-5ꢇ), 114.58 (C-8ꢇ), 115.01 (C-7ꢇ), 124.49 (C-10ꢇ), 139.70 (C-6ꢇ), 153.23 (C-9ꢇ), 167.68 (O–C–O),
168.34 (O–C=O), 216.67 (C-2, C=O).
4ꢇꢇ,4ꢇꢇ-Dimethyl-6ꢇ-phenyl-1ꢇ-{(1R,2S,3R,4S)-1,7,7-trimethyl-2-hydroxybicyclo[2.2.1]heptan-3-yl}-2ꢇ,4ꢇ-dihydro-
–1
1ꢇH-spiro[cyclohexane-1ꢇꢇ,3ꢇꢇ-quinoline]-2ꢇꢇ,6ꢇꢇ-dione (9d), C H NO , yield 76%, mp 157–159°C. IR spectrum (ꢆ, cm ):
32 39
3
3380, 2955, 2927, 2872, 1727, 1696, 1613, 1486, 1370, 1199, 1064, 761, 697.
PMR spectrum (CDCl , , ppm, J/Hz): 0.91 (3H, s, CH -9), 0.96 (3H, s, CH -8), 1.05 (3H, s, CH -10), 1.15 (3H, s,
3
3
3
3
CH ), 1.21 (3H, s, CH ), 1.55–1.65 (2H, m, H-5), 1.91 (1H, br., OH), 2.42 (1H, d, J = 3.9, H-4), 2.51 (1H, d, J = 13.6), 2.54
3
3
(1H, d, J = 13.6), 2.86 (1H, d, J = 14.5), 2.88 (1H, d, J = 14.5), 3.11 (1H, d, J = 15.5), 3.15 (1H, d, J = 3.5, H-2), 3.34 (1H, d,
J = 15.5), 3.37 (1H, d, J = 11.9), 3.47 (1H, d, J = 6.5, H-3), 3.81 (1H, d, J = 11.9), 3.88 (1H, br., OH), 6.91 (1H, d, J = 8.4), 7.27
(2H, m), 7.40 (3H, m), 7.52 (2H, d, J = 7.4).
13
C NMR spectrum (CDCl , , ppm): 11.44 (C-9), 22.16 (C-8), 22.58 (C-10), 27.75 (CH ), 28.99 (C-6), 29.58 (CH ),
3
3
3
30.93 (C-4ꢇꢇ), 32.47 (C-4ꢇ), 36.26 (C-5), 46.86 (C-4), 47.51 (C-7), 48.28 (C-2ꢇ), 49.49 (C-1), 51.60 (CH ), 51.94 (CH ), 62.90
2
2
(C-spiro), 70.89 (C-3), 82.73 (C-2), 113.99, 120.47, 126.50, 126.56, 126.89 (2C), 127.01, 128.79 (2C), 131.41, 140.86, 145.48,
206.79 (C=O), 207.05 (C=O).
Bis-N,Nꢇ-(1,7,7-trimethylbicyclo[2.2.1]heptan-2-on-3-exo-yl)-p-phenylenediamine (11), C H N O , yield 90%,
26 36
2 2
–1
mp 206–207°C, [ꢁ] +131.7° (c 0.4, CHCl ). IR spectrum (ꢆ, cm ): 3360 (NH), 2956, 2879, 2819, 1745 (C=O), 1518
D
3
(C=O), 1477, 1448, 1317, 1263, 1026, 817.
PMR spectrum (CDCl , , ppm, J/Hz): 0.95 (6H, s, H-8,10), 0.97 (3H, s, H-9), 1.55–1.80 (2H, m, H-5), 1.60 and 2.07
3
(both 1H, m, H-6), 2.21 (1H, d, J = 4.1, H-4), 3.30 (1H, s, H-3), 3.79 (1H, br., NH), 6.51 (2H, s, Ar).
13
C NMR spectrum (CDCl , , ppm): 9.3 (C-9), 20.5 (C-8), 20.8 (C-10), 26.2 (C-5), 28.7 (C-6), 46.9 (C-7), 47.7
3
(C-4), 56.5 (C-1), 65.9 (C-3), 114.7 (C-12), 140.6 (C-11), 218.0 (C=O).
1ꢇ,6ꢇ-Di-(1,7,7-trimethyl-3-oxobicyclo[2.2.1]heptan-2-yl)-4,4,4ꢇꢇ,4ꢇꢇ-tetramethyl-1ꢇ,2ꢇ,3ꢇ,4ꢇ,5ꢇ,7ꢇ,8ꢇ,9ꢇ-
octahydrobispiro[cyclohexane-1,3ꢇ-pyrido[2,3-g]quinoline-8ꢇ,1ꢇꢇ-cyclohexane]-2,2ꢇꢇ,6,6ꢇꢇ-tetraone (12), C H N O , yield
46 60
2 6
–1
85%, mp 201–202°C, [ꢁ] –9.4° (c 0.4, CHCl ). IR spectrum (ꢆ, cm ): 2958. 2872, 1743, 1697 (C=O), 1506 (C=C), 1456,
D
3
1423, 1390, 1371, 1325, 1242 (C–O–C), 1010, 954, 860.
PMR spectrum (CDCl , , ppm, J/Hz): 0.85 (3H, s, H-9), 0.88 (3H, s, H-8), 0.93 (3H, s, H-10), 0.99 (3H, s, CH ),
3
3
1.20 (3H, s, CH ), 1.55–1.78 (3H, m, 2H-5, H-6), 2.07 (1H, m, H-6), 2.32 (1H, d, J = 4.1, H-4), 2.43 (2H, m, J = 14.8), 2.89
3
(1H, d, J = 14.4), 3.05 (1H, d, J = 15.9), 3.14 (1H, d, J = 15.9), 3.23 (1H, d, J = 14.4), 3.4 (1H, s, H-3), 3.56 (1H, d, J =11.8),
3.71 (1H, d, J = 11.8), 6.28 (1H, s, Ar), eight doublets in the range 2.43-3.71, methylene protons of the spiro-ring.
13
C NMR spectrum (CDCl , , ppm): 9.9 (C-9), 20.8 (C-8), 21.3 (C-10), 26.8 (C-5), 27.0 (C-27), 28.4 (C-6), 30.2
3
(C-18), 30.4 (C-26), 30.9 (C-23), 46.1 (C-7), 48.7 (C-4), 51.6 (C-20), 51.7 and 51.8 (C-22,24), 57.9 (C-1), 66.3 (C-spiro), 68.8
(C-3), 115.0 (C-12), 123.0 (C-17), 138.1 (C-11), 206.5 (C=O), 207.1 (C=O), 217.3 (C-2, C=O).
ACKNOWLEDGMENT
We thank P. A. Slepukhin of I. Ya. Postovskii Institute of Organic Chemistry, Ural Branch, RAS, for performing the
XSA. The work was supported by the RF President (Program for Support of Leading Scientific Schools, Grant NSh-4028.2008.3)
and the RFBR 08-03-90011 Bel_a.
410

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