Synthesis, guest-binding, and reduction-responsive degradation properties of water-soluble cyclophanes having disulfide moieties

Article abstract of DOI:10.1021/jo400591w

Water-soluble cationic cyclophane having diphenyl disulfide moieties (1a) was synthesized as a reduction-responsive degradable host. The stoichiometry for the complex of 1a with anionic fluorescence guests, such as 4,4′-bis(1-anilinonaphthalene-8-sulfonate) (Bis-ANS) and 4-(1-pyrene)-butanoic acid (PBA), was confirmed to be 1:1 host:guest by a Job plot. The binding constants (K) of 1a toward Bis-ANS and PBA were evaluated to be 6.7 × 10³ and 4.5 × 10⁴ M^-1, respectively, as confirmed by fluorescence spectroscopy. Reduction of disulfide bonds of 1a by dithiothreitol gave its reduced form having poor guest-binding affinity that led to release of the entrapped guest molecules to the bulk aqueous phase. Meanwhile, anionic cyclophane 1b, which was derived from 1a by a reaction with succinic anhydride, binds cationic anticancer drugs, such as daunorubicin hydrochloride (DNR) and doxorubicin hydrochloride (DOX), with a K of 2.1 × 10³ and 7.5 × 10² M^-1, respectively. A similar reduction-responsive guest release feature was observed when DNR and DOX were employed as a guest for complexation with 1b.

Full text of DOI:10.1021/jo400591w

Article
pubs.acs.org/joc
Synthesis, Guest-Binding, and Reduction-Responsive Degradation
Properties of Water-Soluble Cyclophanes Having Disulfide Moieties
Osamu Hayashida,* Kazuaki Ichimura, Daisuke Sato, and Terutaka Yasunaga
Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Fukuoka 814-0180, Japan
S
* Supporting Information
ABSTRACT: Water-soluble cationic cyclophane having di-
phenyl disulfide moieties (1a) was synthesized as a reduction-
responsive degradable host. The stoichiometry for the complex
of 1a with anionic fluorescence guests, such as 4,4′-bis(1-
anilinonaphthalene-8-sulfonate) (Bis-ANS) and 4-(1-pyrene)-
butanoic acid (PBA), was confirmed to be 1:1 host:guest by a
Job plot. The binding constants (K) of 1a toward Bis-ANS and
PBA were evaluated to be 6.7 × 103 and 4.5 × 104 M−1, respectively, as confirmed by fluorescence spectroscopy. Reduction of
disulfide bonds of 1a by dithiothreitol gave its reduced form having poor guest-binding affinity that led to release of the
entrapped guest molecules to the bulk aqueous phase. Meanwhile, anionic cyclophane 1b, which was derived from 1a by a
reaction with succinic anhydride, binds cationic anticancer drugs, such as daunorubicin hydrochloride (DNR) and doxorubicin
hydrochloride (DOX), with a K of 2.1 × 103 and 7.5 × 102 M−1, respectively. A similar reduction-responsive guest release feature
was observed when DNR and DOX were employed as a guest for complexation with 1b.
INTRODUCTION
■
Currently, the development of functionalized host vehicles
having stimuli-responsive binding capabilities1 has attracted
much attention for targeted drug delivery2 and controlled guest
Figure 1. Schematic representation for the reduction-responsive
release.3 Among all functionalities, disulfide bonds have been
degradation of cyclophanes having disulfide moieties with a
frequently utilized as a reductively degradable linkage.4 A great
concomitant release of guest molecules.
number of artificial vehicles, such as disulfide-functionalized
polymeric micelles,5 vesicles,6 and nanoparticles,7 have been
water-soluble cationic cyclophane having disulfide moieties in
the macrocyclic skeleton. Furthermore, we also designed an
analogous derivative with terminal anionic side chains. We
describe herein the synthesis of the water-soluble cyclophanes
having disulfide moieties, their guest-binding behavior, and
their reduction-responsive degradation properties with an
emphasis on the release of guest molecules.
reported. On the other hand, cyclophanes with a sizable
internal cavity8 are also typical hosts capable of providing
hydrophobic binding sites. Moreover, a wide synthetic variation
can be achieved by introducing various functional groups into
appropriate sites of the cyclophanes.9 On these grounds, we
became interested in the development of well-defined and
cleavable cyclophanes based on disulfide linkages. In the
preceding paper, we have developed a cleavable cyclophane
dimer on the basis of a molecular design that allows connection
of two tetraaza[6.1.6.1]paracyclophane10 skeletons with a
disulfide linkage.11 The host showed enhanced guest binding
affinity relative to that by monocyclic cyclophane,12 as
confirmed by fluorescence spectroscopy. Reduction of the
disulfide bond of the host gave monocyclic cyclophanes having
less guest-binding affinity.11 In the course of our ongoing
research on reduction-responsive degradable cyclophanes, a
challenging subject of investigation is the development of
functionalized cyclophanes having disulfide moieties within the
macrocyclic skeleton. Figure 1 shows our concept on reduction-
responsive release of guest molecules. That is, the reduction of
disulfide bonds of cyclophanes gave the structural fragments
having poor guest-binding affinity and, consequently, showed
release of the entrapped guest molecules to the bulk aqueous
phase. For the proof-of-principle experiments, we developed a
RESULTS AND DISCUSSION
■
Design and Synthesis of Cyclophanes Having
Diphenyl Disulfide Moieties. First, we designed 1,2,21,22-
tetrathia-9,14,29,34-tetraaza[6.2.6.2]paracyclophane (4) as a
reduction-responsive degradable cyclophane. This compound
can provide two disulfide moieties responsible for degradation.
It is also desirable for water-soluble hosts to provide
hydrophobic binding sites that can be desolvated upon guest
incorporation. In addition, hydrophobic binding sites must be
reasonably separated from hydrophilic groups that are required
for giving water solubility to cyclophanes, so that the
hydrophobic efficiency is maintained for guest incorporation.13
We have now designed cationic and anionic cyclophanes having
Received: March 20, 2013
© XXXX American Chemical Society
A
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
of the macrocyclic skeleton through amide linkages, 1a and 1b,
respectively (Figure 2).
Water-soluble cyclophanes having diphenyl disulfide moieties
1a and 1b were prepared by following the reaction sequence
given in Scheme 1. A precursor (3) of 4 was synthesized by
cyclization of 1,4-dibromobutane with N,N′-bistosyl-4,4′-dithio-
dianiline (2),14 which was prepared from dithiodianiline by a
reaction with tosyl chloride. Acidic hydrolysis of 3 by
hydrobromic acid in phenol gave 4. Cationic cyclophane 1a
was synthesized by condensation of 4 with boc-β-alanine in the
presence of dicyclohexylcarbodiimide (DCC), followed by a
treatment with TFA. 1a was then converted to a cyclophane
having carboxylic acid residues 1b by a reaction with succinic
anhydride. In addition, a thiol derivative in the reduced form of
the cyclophanes (6) was also obtained in the reduction of 1a by
using dithiothreitol (DTT). New compounds were fully
characterized by means of spectroscopy (IR, 1H and 13C
NMR, and TOF-MS) and elemental analysis (see the
Supporting Information).
On the basis of the molecular mechanics studies of
cyclophane 1a, followed by molecular dynamics simulations,15
1a was found to provide relatively large internal cavities with
inner diameters of ca. 11−12 Å, as shown in Figure 3.
Peripheral polar side chains with reasonably separated distances
from the cavity were expected to confer the advantage of
enhanced solubility in neutral aqueous media. From a practical
standpoint, cyclophanes 1a and 1b had good H2O solubilities of
220 and 6.7 mg/mL, respectively. These results indicate that 1a
and 1b having hydrophobic cavities were expected to act as
water-soluble hosts.
Figure 2. Water-soluble cyclophanes having disulfide moieties 1a and
1b.
disulfide moieties by introducing polar side chains with a
terminal ammonium and carboxylate residue on the periphery
Scheme 1. Preparation of Cyclophanes Having Disulfide Moieties 1a and 1b
B
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
of 1a, as shown in Figure 5. A similar fluorescent character was
also observed for the complexation of 1a with PBA (Figure 5),
even though the fluorescence intensity originating from PBA
was subject to decrease upon complexation. The present host
was found to undergo complexation with the guests in a 1:1
molar ratio of host to guest, as confirmed by the Job′s
continuous variation method (see the Supporting Information).
Binding constants for the formation of inclusion complexes of
1a with the identical guests in a 1:1 molar ratio (K) were
evaluated on the basis of the Benesi−Hildebrand relationship;19
K = 6.7 × 103 and 4.5 × 104 M−1 for Bis-ANS and PBA,
respectively. On the other hand, the fluorescence spectral
changes were negligible upon addition of anionic cyclophane
1b to the aqueous HEPES buffer containing Bis-ANS and PBA.
Naturally, these anionic guests were not incorporated into the
cavity of anionic cyclophane 1b, reflecting an electrostatic
repulsion.20 By contrast, cationic fluorescent guests, such as 1-
pyrenemethylamine hydrochloride (PMA),21 were bound to
anionic host 1b (K, 1.5 × 104 M−1 for complexation with
PMA), whereas 1a showed almost no affinity for PMA. In
addition, anionic host 1b also binds cationic anticancer drugs,22
such as daunorubicin hydrochloride (DNR) and doxorubicin
hydrochloride (DOX), as shown in Figure 6. The K values for
complexation of 1b with DNR and DOX were evaluated to be
2.1 × 103 and 7.5 × 102 M−1, respectively.
Small fluorescent guests, such as 6-p-toluidino-naphthalene-
2-sulfonate (TNS), are frequently used as a suitable guest for
water-soluble cyclophanes based on a tetraaza[6.1.6.1]para-
cyclophane skeleton.18 However, TNS molecules were not
incorporated into the large tetrathia-tetraaza[6.2.6.2]paracyclo-
phane skeleton of 1a (see the Supporting Information). These
results suggested that 1a was capable of performing size-
sensitive molecular discrimination originating from the
geometry of the hydrophobic cavity.
Figure 3. Computer-generated CPK models for 1a (a) and 1b (b).
Carbon, hydrogen, oxygen, nitrogen, and sulfur atoms are shown in
green, white, red, blue, and yellow, respectively.
Guest-Binding of Cyclophanes. The guest-binding
affinity of 1a toward anionic fluorescent guests, such as 4,4′-
bis(1-anilinonaphthalene-8-sulfonate) (Bis-ANS)16 and 4-(1-
pyrene)butanoic acid (PBA)17 (Figure 4), whose emissions are
sensitive to change in the microenvironments experienced by
molecules,18 was examined by fluorescence spectroscopy in
aqueous HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethane-
sulfonic acid) buffer (0.01 M, pH 7.4, 0.15 M with NaCl) at
298 K. The fluorescence intensity that originated from Bis-ANS
increased along with a concomitant blue shift of the
fluorescence maximum upon addition of a large excess amount
Reduction-Responsive Guest Release of Cyclophanes.
1
Reduction of 1a was investigated by H NMR spectroscopy in
CD3OD at 298 K. Aromatic proton signals at 7.24 and 7.60
ppm originating from 1a were disappearing in the presence of
an excess amount of DTT (20 equiv) as a reducing agent, as
shown in Figure 7. Newly appeared proton signals at 7.07 and
7.38 ppm were attributable to those of the reduced form of 1a,
which was identified with 6 (Figure 7). In addition, ESI-TOF
Figure 4. Hydrophobic fluorescent guests.
C
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
Figure 6. Fluorescence spectral changes for an aqueous solution of
DNR (a) and DOX (b) upon addition of 1b in HEPES buffer at 298
K. [DNR] = [DNR] = 2.5 μM. [1] = 0, 50, 100, 150, 200, 250, 300,
350, 400, 450, and 500 μM (from top to bottom). Ex. 460 nm. Inset:
the corresponding titration curves.
almost entrapped guest molecules by 1a were released to the
bulk aqueous phase after 160 min of incubation, reflecting the
reduction-responsive cleavage of the macrocycle. Similarly,
upon addition of GSH (10 mM) to a HEPES buffer solution
containing host−guest complexes of 1a with Bis-ANS, a
decrease in fluorescence intensity was also observed, reflecting
the release of the entrapped guest molecules (Figure 9b). In
addition, similar reduction-responsive guest releasing behavior
of 1b was also observed by using DNR and DOX as a guest
(see the Supporting Information).
Figure 5. Fluorescence spectral changes for aqueous solutions of 1a
with Bis-ANS (a), 1a with PBA (b), and 1b with PMA (c) in HEPES
buffer at 298 K. [Bis-ANS] = [PBA] = [PMA] = 1.0 μM. [1] (for Bis-
ANS) = 0, 50, 100, 150, 200, 250, 300, 350, 400, 450, and 500 μM
(from bottom to top). [1a] (for PBA) = [1b] (for PMA) = 0, 5, 10,
15, 20, 25, 30, 35, 40, 45, and 50 μM (from top to bottom). Ex. 390,
322, and 322 nm for Bis-ANS, PBA, and PMA, respectively. Inset: the
corresponding titration curves.
CONCLUSION
■
Water-soluble cyclophanes 1a and 1b having disulfide moieties
were successfully synthesized. Cationic host 1a bound anionic
guests, such as Bis-ANS and PBA, whereas anionic host 1b
bound cationic guests, such as DNR and DOX. In addition, the
entrapped guest molecules by the hosts were released to the
bulk phase by a treatment with DTT. The degradation of the
present cyclophanes and the guest release under reducing
conditions, such as intracellular environments, is a future
subject of interest to be carried out.
MS spectroscopy showed that thiol derivative 6 was
predominantly obtained by this procedure, as shown in Figure
8; m/z 447.15 [M + H]+. Similar reduction of 1a was also
observed by using glutathione (GSH) in place of DTT.
The reduction-responsive guest-releasing behavior of 1a was
investigated in a similar manner by fluorescence spectroscopy.
Upon addition of DTT to a HEPES buffer solution containing
host−guest complexes of 1a with Bis-ANS, the fluorescence
intensity that originated from the guest molecules was subject
to decrease, as shown in Figure 9a. These results indicate that 6
has almost no guest-binding affinity23 generated by the
reduction of the disulfide bond of 1a by DTT. Accordingly,
EXPERIMENTAL SECTION
■
1,2,21,22-Tetrathia-9,14,29,34-tetratosyl-9,14,29,34-
tetraaza[6.2.6.2]paracyclophane (3). A solution of 214 (4.6 g, 8.3
mmol) and 1,4-dibromobutane (1.8 g, 8.3 mmol) in dry N,N-
dimethyl-formamide (DMF, 20 mL) were added dropwise to a
solution of K2CO3 (5.7 g, 41 mmol) in DMF (40 mL) for 5 h at 90
°C, and the resulting mixture was stirred for 12 h at room temperature.
The solution was stirred for overnight at room temperature. The
resulting mixture was added to H2O (300 mL) and stirred for 1 h at
D
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
Figure 7. 1H NMR spectra of 1a (a) and 6 (c) in CD3OD at 298 K. 1H NMR spectrum of a solution of 1a (0.5 mM) and DTT (10 mM) in CD3OD
at 298 K (b).
Figure 8. ESI-TOF MS spectra of a solution of 1a (0.5 mM) and DTT (10 mM) in methanol.
Figure 9. Time course for changes of fluorescence intensity originating from Bis-ANS (1.0 μM) in HEPES buffer in the presence of 1a (50 μM)
upon addition of DTT (5 mM) (a) and GSH (10 mM) (b) at 298 K.
room temperature. Precipitates were recovered by filtration, washed
with H2O, and dried under reduced pressure at room temperature to
give a white solid. The mixture of the white solid and ethyl acetate
(EtOAc, 100 mL) was refluxed for 1 h and cooled to room
temperature. Precipitates were recovered by filtration, washed with
EtOAc, and dried under reduced pressure at room temperature to give
a white solid. The white solid was added to CHCl3 (60 mL), and the
resulting mixture was stirred for 1 h at room temperature. The
separated precipitates were collected by filtration, washed with CHCl3,
and dried in vacuo to give a white solid. 2.8 g (55%): mp 140−143 °C.
1H NMR (400 MHz, CDCl3, 298 K) δ 1.40 (s, 8H), 2.41 (s, 12H),
3.52 (t, 8H), 6.83 (d, 8H), 7.23 (d, 8H), 7.37 (d, 8H), and 7.42 (d,
8H). 13C NMR (100 MHz, CDCl3, 298 K) δ 21.8, 24.3, 49.0, 127.6,
127.9, 129.3, 135.0, 136.4, 138.1, and 143.9. IR 1643 cm−1 (SO2−N).
Found: C, 57.89; H, 4.87; N, 4.60. Calcd for C60H60N4O8S8·H2O: C,
58.13; H, 5.04; N, 4.52. ESI-TOF MS: m/z 1256.84 [M + Cl]−.
1,2,21,22-Tetrathia-9,14,29,34-tetraaza[6.2.6.2]paracyclo-
phane (4). An aqueous hydrobromic acid solution (47%, 10 mL) was
added dropwise to a solution of 3 (1.6 g, 1.3 mmol) and phenol (10 g,
0.12 mmol), and the resulting mixture was stirred for 1 h at 90 °C.
E
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
H2O (200 mL) was added to the mixture, which was then washed with
diethyl ether (300 mL). The pH of the solution was adjusted to 11 by
adding sodium hydroxide, and extracted with CHCl3 (100 mL × 3).
The combined organic phase was washed with 5% aqueous sodium
hydroxide (50 mL) and saturated aqueous sodium chloride (50 mL) in
this sequence. After being dried (Na2SO4), the solution was
evaporated to dryness under reduced pressure to give a pale yellow
N8O16S4·H2O: C, 55.11; H, 5.70; N, 8.57. ESI-TOF MS: m/z 1289.44
[M + H]+.
Reduced Form of 1a (6). Dithiothreitol (18 mg, 0.12 mmol, 12
equiv) was added to a solution of 1a (15 mg, 0.01 mmol) in methanol
(2 mL), and the resulting mixture was stirred for 4 days at room
temperature. The solution was evaporated to dryness under reduced
pressure. The crude product was purified by gel filtration
chromatography on a column of Sephadex LH-20 with methanol as
an eluent. Evaporation of the product fraction under reduced pressure
1
solid. 300 mg (38%): mp 146−149 °C. H NMR (400 MHz, CDCl3,
298 K) δ 1.73 (s, 8H), 3.17 (m, 8H), 3.83 (t, 4H), 6.48 (d, 8H), and
7.27 (d, 8H). 13C NMR (100 MHz, CDCl3, 298 K) δ 27.1, 43.5, 113.2,
124.3, 134.5, and 148.8. IR 3395 cm−1 (N−H). Found: C, 63.57; H,
6.08; N, 9.02. Calcd for C32H36N4S4: C, 63.54; H, 6.00; N, 9.26. ESI-
TOF MS: m/z 639.05 [M + Cl]−.
1
gave a white solid. (19 mg, quantitative): mp 60−63 °C. H NMR
(400 MHz, CD3OD, 298 K) δ 1.50 (m, 4H), 2.40 (t, 4H), 3.08 (m,
4H), 3.34 (s, 2H), 3.69 (m, 4H), 7.07 (d, 8H), and 7.38 (d, 8H). 13C
NMR (100 MHz, CD3OD, 298 K) δ 25.6, 31.3, 35.8, 128.1, 128.4,
128.8, 129.2, 129.9, 170.1, and 170.3. IR 1630 cm−1 (CO), 1174
cm−1 (N−H). Found: C, 45.24; H, 4.94; N, 7.84. Calcd for
C26H32F6N4O6S2·H2O: C, 45.08; H, 4.95; N, 8.09. ESI-TOF MS:
m/z 469.10 [M + Na]+, where M denotes the diamine derivative of
cyclophane as the free base.
Cyclophane Bearing Boc-Protected Amines (5). Dicyclohexyl-
carbodiimide (99 mg, 0.48 mmol) was added to a solution of Boc-β-
Ala-OH (91 mg, 0.48 mmol) in dry dichloromethane (DCM, 2 mL) at
0 °C, and the mixture was allowed to stand at the same temperature
while being stirred for 20 min. The mixture was added to a solution of
4 (47 mg, 0.08 mmol,) in dry DCM (5 mL), and the resulting mixture
was stirred for 3 days at room temperature. Precipitates that formed
(N,N′-dicyclohexylurea) were removed by filtration, the solvent was
eliminated under reduced pressure, and the residue was dissolved in
EtOAc (20 mL). Insoluble materials were removed by filtration, and
the filtrate was evaporated to dryness under reduced pressure. The
residue was chromatographed on a column of silica gel (SiO2) with
EtOAc as an eluent. Evaporation of the product fraction under reduced
pressure gave a white solid. 65 mg (63%): mp 100−103 °C. 1H NMR
(400 MHz, CDCl3, 298 K) δ 1.42 (s, 44H), 1.46 (s, 8H), 2.12 (m,
8H), 3.26 (m, 8H), 3.65 (m, 8H), 5.26 (m, 4H), 7.02 (d, 8H), and
7.49 (d, 8H). 13C NMR (100 MHz, CDCl3, 298 K) δ 25.0, 28.7, 35.1,
36.6, 48.7, 79.3, 128.1, 129.2, 137.0, 141.2, 156.1, and 171.6. IR 1645
cm−1 (CO), 3332 cm−1 (N−H), 1166 cm−1 (C−O, Boc). Found:
C, 58.81; H, 6.83; N, 8.63. Calcd for C64H88N8O12S4·H2O: C, 58.78;
H, 6.94; N, 8.63. ESI-TOF MS: m/z 1311.03 [M + Na]+.
Binding Constants of Cyclophane with Fluorescence Guests.
To each solution of a fluorescent guest (1.0 μM) in HEPES buffer
were added increasing amounts of the hosts at 298 K, and the guest
fluorescence intensity was monitored after each addition by excitation
at 390, 322, 322, 460, and 460 nm for Bis-ANS, PBA, PMA, DNR, and
DOX, respectively. An aqueous stock solution of 1b was prepared after
addition of NaOH. The binding constants were calculated on the basis
of the Benesi−Hildebrand method for titration data.
Computational Procedure. The calculations were carried out on
a Pentium 4 3.2 GHz x 2 machine using MacroModel 9.1 molecular
modeling software on a Red Hat Enterprise Linux WS 4.3 operating
system. Molecular mechanics and molecular dynamics methods were
utilized at arriving at the optimized structures. The geometry of 1a and
1b was optimized using molecular mechanics employing the
OPLS_2005 force field for the simulation of the hosts. The geometry
was optimized without any constraints, allowing all atoms, bonds, and
dihedral angles to change simultaneously. The dielectric was set to
distance dependent with a scale factor of 1. A 1 ps molecular dynamics
was carried out in vacuo using the molecular mechanics OPLS_2005
force field under constant temperature conditions (300 K).
Cationic Cyclophane Having Disulfide Moieties (1a).
Trifluoroacetic acid (TFA, 0.25 mL) was added to a solution of
compound 5 (65 mg, 0.05 mmol) in dry DCM (1.5 mL), and the
mixture was stirred for 2 h at room temperature. After the solvent was
evaporated off under reduced pressure, DCM (5 mL) was added to the
residue, and this procedure was repeated three times to remove
remaining TFA. Evaporation of the solvent under reduced pressure
gave a pale white solid. The crude product was purified by gel filtration
chromatography on a column of Sephadex LH-20 with methanol as an
eluent. Evaporation of the product fraction under reduced pressure
gave a white solid (triamine derivative of cyclophane as the
ASSOCIATED CONTENT
* Supporting Information
■
S
NMR spectra for compounds 3, 4, 5, 1a, 1b, and 6; Job plots;
and additional fluorescence titration spectra. This material is
available free of charge via the Internet at http://pubs.acs.org.
1
trifluoroacetic acid salt). 59 mg (88%): mp 118−121 °C. H NMR
AUTHOR INFORMATION
Corresponding Author
*E-mail: hayashida@fukuoka-u.ac.jp.
(400 MHz, CD3OD, 298 K) δ 1.49 (m, 8H), 2.40 (t, 8H), 3.09 (t,
8H), 3.71 (m, 8H), 7.24 (d, 8H), and 7.60 (d, 8H). 13C NMR (100
MHz, CD3OD, 298 K) δ 24.4, 31.4, 35.7, 118.5, 28.1, 129.2, 137.1,
140.7, 161.6, and 170.1. IR 1634 cm−1 (CO). Found: C, 44.75; H,
4.75; N, 8.13. Calcd for C52H60F12N8O12S4·3H2O: C, 44.63; H, 4.75;
N, 8.01. ESI-TOF MS: m/z 889.32 [M + H]+, where M denotes the
tetraamine derivative of cyclophane as the free base.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
Anionic Cyclophane Having Disulfide Moieties (1b). Succinic
anhydride (119 mg, 1.20 mmol) was added to a solution of 1a (200
mg, 0.15 mmol) and triethylamine (0.2 mL) in dry DCM (4 mL) at
room temperature, and the mixture was stirred for 1 day. The solution
was evaporated to dryness under reduced pressure to give a white
solid. The crude product was purified by gel filtration chromatography
on a column of Sephadex LH-20 with methanol as an eluent.
Evaporation of the product fraction under reduced pressure gave a
white solid. The resulting sodium salt was converted into the free acid
by ion-exchange chromatography on a column of Amberlite IR-120B
with methanol as an eluent. Evaporation of the product fraction under
reduced pressure gave a white solid. 160 mg (83%): mp 96−98 °C. 1H
NMR (400 MHz, CD3OD, 298 K) δ 1.47 (s, 8H), 2.20 (t, 8H), 2.38
(t, 8H), 2.52 (t, 8H), 3.67 (m, 8H), 7.17 (d, 8H), and 7.56 (d, 8H).
13C NMR (100 MHz, CD3OD, 298 K) δ 24.6, 29.0, 30.3, 33.9, 35.6,
51.0, 128.3, 129.2, 136.7, 141.4, 171.6 173.3, and 175.0. IR 1727 cm−1
(COOH). Found: C, 55.27; H, 5.87; N, 8.65. Calcd for C60H72-
■
The present work is partially supported by a Grant-in-Aid (No.
24550166) from the Ministry of Education, Culture, Science,
Sports and Technology of Japan.
REFERENCES
■
(1) (a) Xavier, G.; Rebek, J., Jr. Angew. Chem., Int. Ed. Engl. 1996, 35,
1225−1228. (b) Biros, S. M.; Rebek, J., Jr. Chem. Soc. Rev. 2007, 36,
93−104. (c) Berryman, O. B.; Sather, A. C.; Lideo, A.; Rebek, J., Jr.
Angew. Chem., Int. Ed. 2011, 50, 9400−9403.
(2) (a) Tom, B.; Tjama, T.; Judith, W.; Rebek, J., Jr. Science 1988,
242, 266−268. (b) Busseron, E.; Rebek, J., Jr. Org. Lett. 2010, 12,
4828−4831.
(3) Bae, Y.; Kataoka, K. Adv. Drug. Delivery Rev. 2009, 61, 768−784.
(4) (a) Gosselin, M. A.; Guo, W.; Lee, R. J. Bioconjugate Chem. 2001,
12, 989−994. (b) Cai, X.; Dong, C.; Dong, H.; Wang, G.; Pauletti, G.
F
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
M.; Pan, X.; Wen, H.; Mehl, I.; Li, Y.; Shi, D. Biomacromolecules 2012,
13, 1024−1034.
(c) Abeylath, S. C.; Amiji, M. M. Bioorg. Med. Chem. 2011, 19,
6167−6173.
(23) Almost no guest-binding affinity of 6 toward Bis-ANS was
confirmed by fluorescence spectroscopy (see the Supporting
Information).
(5) (a) Koo, A. N.; Lee, H. J.; Kim, S. E.; Chang, J. H.; Park, C.; Kim,
C.; Park, J. H.; Lee, S. C. Chem. Commun. 2008, 6570−6572.
(b) Yoon, J. A.; Benchrif, S. A.; Aksak, B.; Kim, E. K.; Kowalewski, T.;
Oh, J. K.; Matyjaszewski, K. Chem.Asian J. 2011, 6, 128−136.
(6) (a) Cerritelli, S.; Velluto, D.; Hubbell, J. A. Biomacromolecules
2007, 8, 1966−1972. (b) Tang, L. Y.; Wang, Y. C.; Li, Y.; Du, J. Z.;
Wang, J. Bioconjugate Chem. 2009, 20, 1095−1099.
(7) (a) Letsinger, R. L.; Elghanian, R.; Viswanagham, G.; Mirkin, C.
A. Bioconjugate Chem. 2000, 11, 289−291. (b) Durocher, S.; Rezaee,
A.; Hamm, C.; Rangan, C.; Mittler, S.; Mutus, B. J. Am. Chem. Soc.
2009, 131, 2475−2477.
(8) (a) Vogtle, F.; Seel, C.; Windscheif, P. M. In Comprehensive
̈
Supramolecular Chemistry; Vogtle, F., Ed.; Pergamon: Oxford, U.K.,
̈
1996; Vol. 2, p 211. (b) Ariga, K.; Terasaka, Y.; Sakai, D.; Tsuji, H.;
Kikuchi, J. J. Am. Chem. Soc. 2000, 122, 7835−7836. (c) Nakai, T.;
Kanamori, T.; Sando, S.; Aoyama, Y. J. Am. Chem. Soc. 2003, 125,
8465−8475.
(9) (a) Hayashida, O.; Ogawa, N.; Uchiyama, M. J. Am. Chem. Soc.
2007, 129, 13698−13705. (b) Hayashida, O.; Sato, D. J. Org. Chem.
2008, 73, 3205−3211. (c) Hayashida, O.; Sato, D. Polym. Adv. Technol.
2010, 21, 96−99. (d) Hayashida, O.; Nakashima, T. Chem. Lett. 2011,
40, 134−135.
(10) (a) Odashima, K.; Itai, A.; Iitaka, Y.; Arata, Y.; Koga, K.
Tetrahedron Lett. 1980, 21, 4347−4350. (b) Koga, K.; Odashima, K. J.
Inclusion Phenom. 1989, 7, 53−60. (c) Odashima, K.; Itai, A.; Iitaka, Y.;
Koga, K. J. Org. Chem. 1991, 50, 4478−4484.
(11) (a) Hayashida, O.; Ichimura, K. Chem. Lett. 2012, 41, 1650−
1651. Other cyclophanes having disulfide bonds: (b) Bottino, F.;
Foti, S.; Pappalardo, S. J. Chem. Soc., Perkin Trans. 1 1977, 1652−1654.
(c) Bottino, F.; Foti, S.; Pappalardo, S.; Finocchiaro, P.; Ferrugia, M. J.
Chem. Soc., Perkin Trans. 1 1979, 198−200. (d) Pappalardo, S.;
Bottino, F.; Ronsisvalle, G. M. J. Chem. Soc., Perkin Trans. 2 1984,
1001−1004. (e) Tam-Chang, S.; Stehouwer, J. S.; Hao, J. J. Org. Chem.
1999, 64, 334−335. (f) Lesot, P.; Aroulanda, C.; Berdague, P.;
Zimmermann, H.; Luz, Z. J. Phys. Chem. B 2011, 115, 11793−11804.
(g) Kimura, T.; Ichikawa, H.; Fujio, T.; Kawai, Y.; Ogawa, S. J. Sulfur
Chem. 2012, 33, 17−25.
(12) Hayashida, O.; Nakashima, T. Bull. Chem. Soc. Jpn. 2012, 85,
715−723.
(13) (a) Hayashida, O.; Hamachi, I. J. Org. Chem. 2004, 69, 3509−
3516. (b) Hayashida, O.; Kitaura, A. Chem. Lett. 2006, 35, 808−809.
(14) Foye, W. O.; Speranza, J. J. Pharm. Sci. 1970, 59, 259−261.
(15) The calculations were carried out by using Macromodel 7.5
software.
(16) (a) Takashi, R.; Tonomura, Y.; Morales, M. F. Proc. Natl. Acad.
Sci. U.S.A. 1977, 74, 2334−2338. (b) Cordeiro, Y.; Lima, L. M. T. R.;
Gomes, M. P. B.; Foguel, D.; Silva, J. L. J. Biol. Chem. 2004, 279,
5346−5352. (c) Lookene, A.; Zhang, L.; Tougu, V.; Olivecrona, G. J.
Biol. Chem. 2003, 278, 37183−37194.
(17) (a) Angeles H., M.; Ehli, C.; Campidelli, S.; Gutierrez, M.; Hug,
G. L.; Ohkubo, K.; Fukuzumi, S.; Prato, M.; Martin, N.; Guldi, D. M. J.
Am. Chem. Soc. 2008, 130, 66−73. (b) Bartelmess, J.; Ballesteros, B.;
de la Torre, G.; Kiessling, D.; Campidelli, S.; Prato, M.; Torres, T.;
Guldi, D. M. J. Am. Chem. Soc. 2010, 132, 16202−16211.
(18) Slavik, J. Biochem. Biophys. Acta 1982, 694, 1−25.
(19) Benesi, H. A.; Hildebrand, J. H. J. Am. Chem. Soc. 1949, 71,
2703−2707.
(20) (a) Murakami, Y.; Hayashida, O.; Ito, T.; Hisaeda, Y. Pure. Appl.
Chem. 1993, 65, 551−556. (b) Murakami, Y.; Hayashida, O.; Nagai, Y.
J. Am. Chem. Soc. 1994, 116, 2611−2612.
(21) (a) Xin, H.; Woolley, A. T. J. Am. Chem. Soc. 2003, 125, 8710−
8711. (b) Dale, T. J.; Rebek, J., Jr. J. Am. Chem. Soc. 2006, 128, 4500−
4501.
(22) (a) Priebe, W.; Neamati, N.; Perez-Soler, R. J. Antibiot. 1990, 43,
838−846. (b) Horichi, N.; Tapiero, H.; Sugimoto, Y.; Bungo, M.;
Nishiyama, M.; Fourcade, A.; Lampidis, T. J.; Kasahara, K.; Sasaki, Y.;
Takahashi, T.; Saijo, N. Cancer Res. 1990, 50, 4698−4701.
G
dx.doi.org/10.1021/jo400591w | J. Org. Chem. XXXX, XXX, XXX−XXX