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<A NAME="RG24409ST-24">24</A>
General Procedure
for the Synthesis of the Tetracationic Salts 16a-d
Hexachlorobuta-1,3-diene
(10b, 4 mmol, 1.04 g) was dissolved in
the solvent specified in Table
[¹]
and
then 20 mmol of the corresponding heteroaromatic nucleophiles were
added. The mixture was then stirred at the temperature presented
in Table
[¹]
. The
resulting precipitate was collected by filtration and washed subsequently
with EtOAc. Finally, this solid was recrystallized from MeCN-MeOH
(95:5). Thus, for the synthesis of 16c 3.28
g of 4-(morpholin-1-yl)pyridine were used. Decomposition of 16c >208 ˚C. ¹H NMR
(400 MHz, D2O): δ = 8.18 (d, J = 7.8 Hz,
4 H, α-H), 8.10 (d, J = 7.8
Hz, 4 H, α′-H), 7.31 (d, J = 7.8
Hz, 4 H, β-H), 7.23 (d, J = 7.8
Hz, 4 H, β′-H), 3.92 (s, 16 H), 3.91 (s, 16 H). ¹³C
NMR (100 MHz, D2O): δ = 156.6,
155.5, 140.5, 140.3, 137.8, 120.2, 109.6, 108.7, 65.7, 65.6, 47.7,
47.6.
IR (KBr): 3417, 3071, 1639, 1565, 1431, 1107, 1038,
824
cm-¹. ESI-MS: m/z = 881 [M4+ + 3
Cl-], 193.6 [M4+/4].
Anal. Calcd (%) for C40H48Cl6N8O4˙9
H2O: C, 44.50; H, 6.12; N, 10.40. Found: C, 44.46; H,
5.62; N, 10.56.
<A NAME="RG24409ST-25">25</A>
General Procedure
for the Reaction of 16a-d with Halogens to 17a-d
The
salts 16a-d (0.25
mmol) were dissolved in AcOH or H2O (20 mL), then bromine
(0.5 mmol) or iodine (0.5 mmol) was added. The precipitate was collected,
filtered, and washed with H2O. The reaction in AcOH afforded recrystallization.
Synthesis of 17a
After 5 min of
stirring the reaction mixture containing bromine in AcOH at r.t.
was filtered, and the resulting solid was washed. After crystallization
in 2-PrOH-MeCN (1:2) orange crystals were obtained, mp
234-236 ˚C. ¹H NMR (400
MHz, DMSO): δ = 8.54 (d, J = 7.8
Hz, 4 H, α-H), 7.26 (d, J = 7.8
Hz, 4 H, β-H), 3.35 (s, 12 H). ¹³C
NMR (100 MHz, DMSO): δ = 156.4,
140.5, 131.2, 123.1, 108.6, 40.7. IR (KBr): 3091, 3054, 1646, 1580,
1340, 1179, 815 cm-¹. ESI-MS: m/z = 512.5 [M²+ + Br-],
217 [M²+/2].
Anal. Calcd (%) for C18H20Br2Cl4N4˙H2O:
C, 35.32; H, 3.62; N, 9.15. Found: C, 35.43; H, 3.41; N, 9.37.
<A NAME="RG24409ST-26">26</A>
X-ray Structure
Analysis for C
18
H
22
Br
2
Cl
4
N
4
O
A suitable single crystal of the title compound was selected under
a polarization microscope and mounted in a glass capillary (d = 0.3 mm).
The crystal structure was determined by X-ray diffraction analysis
using graphite monochromated Mo Kα radiation [0.71073 Å; T = 223 (2)
K], whereas the scattering intensities were collected with
a single crystal diffractometer (STOE IPDS II). The crystal structure
was solved by direct methods using SHELXS-97 and
refined using alternating cycles of least-squares refinements against F
²
(SHELXL-97).³¹ All
non-H atoms were located in difference Fourier maps and were refined
with anisotropic displacement parameters. The H positions were determined by
a final difference Fourier synthesis. C18H22Br2Cl4N4O (M = 612.00
g mol-¹) crystallized in the monoclinic
space group P21/n (no. 14), lattice parameters a = 10.188
(2) Å, b = 16.462
(2) Å, c = 18.298
(2) Å, β = 104.88
(1)˚, V = 2966.1
(6) ų, Z = 4, d
calc
= 1.370
g cm-³, F(000) = 1280 using
5433 independent reflections and 405 parameters. R1 = 0.0609, wR2 = 0.1268 [I > 2σ(I)], goodness of fit on F
²
= 1.103,
residual electron density = 0.854 and -0.671
e Å-³. Further details of
the crystal structure investigations have been deposited with the
Cambridge Crystallographic Data Center, CCDC 739729. Copies of this
information may be obtained free of charge from The Director, CCDC,
12
Union Road, Cambridge, CB2 1EZ, UK [fax: +44 (1223)336033;
e-mail: fileserv@ccdc.ac.uk or
http://www.ccdc.cam.ac.uk].
<A NAME="RG24409ST-27">27</A>
General Procedure
for the Synthesis of Thiophenes 19a-c
In
a sealed tube of 16a-c (0.25 mmol) and sulfur (0.5 mmol) in
DMF (15 mL) were reacted at reflux temperature for 3 h. The dark
brown solution was poured into Et2O (150 mL). The resulting
precipitate was filtered off and washed with Et2O.
Anion Exchange to Hexafluorophosphate
To
a stirred solution of 19a 2Cl- (0.5
mmol, 0.233 g) in H2O (10 mL) was added NaPF6 (1.5
mmol, 0.252 g) in H2O (10 mL). After 5 min of stirring,
the resulting precipitate was filtered off and dried in vacuo. Finally,
a light brown solid was obtained, mp 222-224 ˚C. ¹H
NMR (200 MHz, acetone-d
6): δ = 8.33
(d, J = 7.8
Hz, 4 H, α-H), 7.34 (d, J = 7.8
Hz, 4 H, β-H), 3.48 (s, 12 H). ¹³C
NMR (50 MHz, acetone-d
6): δ = 158.7,
144.3, 136.3, 123.5, 109.9, 41.8. IR (KBr): 3182, 2946,
1650, 1562, 1408, 1262, 840 cm-¹. Anal.
Calcd (%) for C18H20Cl2F12N2P2S:
C, 31.55; H, 2.94; N, 8.18. Found: C, 31.43; H, 2.73; N, 8.46.
<A NAME="RG24409ST-28A">28a</A>
Jarkas N.
Voll RJ.
Williams L.
Votaw JR.
Owens M.
Goodman MM.
J.
Med. Chem.
2008,
51:
271
<A NAME="RG24409ST-28B">28b</A>
Allen CFH.
MacKay DD.
Org.
Synth., Coll. Vol. II
1943,
580
<A NAME="RG24409ST-28C">28c</A>
Allen CFH.
MacKay DD.
Org.
Synth.
1932,
12:
76
<A NAME="RG24409ST-29">29</A>
General Procedure
for the Reaction of 16a-d with Sodium Disulfide to 20a-c
Sodium
disulfide was prepared by refluxing of sodium sulfide (0.5 mmol)
with sulfur (0.5 mmol) in dry MeCN (15 mL) at reflux temperature
for 15 min. After this period of time a dark blue solution was obtained.
The salts 16a-c and three
drops of MeOH were then added, respectively. The reaction mixture
was then heated at reflux temperature for additional 3 h. After
cooling, EtOAc (30 mL) was added. The resulting precipitate was
filtered off and washed with EtOAc. Crystallization in MeCN-2-PrOH
gave the corresponding compounds 20a-c. Compound 20a was obtained
as a yellow solid, mp 232-233 (dec.). ¹H
NMR (200 MHz, D2O): δ = 8.19 (d, J = 7.8 Hz,
4 H, α-H), 7.06 (d, J = 7.8
Hz, 4 H, β-H), 3.33 (s, 12 H). ¹³C
NMR (50 MHz, D2O): δ = 157.1,
140.0, 131.2, 123.3, 108.0, 40.2. IR (KBr): 3036, 2647, 1652, 1574,
1576, 1408, 1345, 1204, 816 cm-¹. ESI-MS: m/z = 214 [M²+/2].
Anal. Calcd (%) for C18H22Cl2N4S3˙4
H2O: C, 40.52; H, 5.67; N, 10.50. Found: C, 40.26; H,
5.33; N, 11.08.
<A NAME="RG24409ST-30">30</A>
X-ray Structure
Analysis for Compound 20a
A crystal of the title compound
was selected under a polarization microscope and mounted in a glass
capillary (d = 0.3
mm). The crystal structure was determined by X-ray diffraction analysis
using graphite monochromated Mo Kα radiation [0.71073 Å, T = 223 (2)
K], whereas the scattering intensities were collected with
a single crystal diffractometer (STOE IPDS II). The crystal structure
was solved by Direct Methods using SHELXS-97.
³¹ Despite
of intense efforts, the quality of the crystal was insufficient,
so that the H atoms could not be localized.
<A NAME="RG24409ST-31">31</A>
Sheldrick GM.
SHELXS-97,
SHELXL-97, A Program Package for Crystal Structure
Solution and Refinement
University of Göttingen;
Germany:
1997.