Synthesis, characterization and ion transportation studies of some novel cyclophane amides

Article abstract of DOI:10.1016/j.tet.2005.03.064

Various novel cyclophane amides with a large cavity have been synthesized. The structures of cyclophane amides 14 and 15 were resolved using XRD studies. Cyclophane amide 28 shows a shift in λ_max in the UV/Vis. spectra when treated with Cu (II) ion as well as with Pb (II) ion. Ion transportation studies were carried out with cyclophane amide 14 which proved that the Na⁺ ion passes through the cavity while K⁺ ions are retained.

Full text of DOI:10.1016/j.tet.2005.03.064

Tetrahedron 61 (2005) 5351–5362
Synthesis, characterization and ion transportation studies
of some novel cyclophane amides
b
Perumal Rajakumara, and A. Mohammed Abdul Rasheed
*
aDepartment of Organic Chemistry, University of Madras, Guindy Campus, Chennai 600 025, India
bAmrutanjan Limited, Research and Development Centre, Egattur, Tamil nadu 603103, India
Received 8 December 2004; revised 3 March 2005; accepted 18 March 2005
Available online 20 April 2005
Abstract—Various novel cyclophane amides with a large cavity have been synthesized. The structures of cyclophane amides 14 and 15 were
resolved using XRD studies. Cyclophane amide 28 shows a shift in lmax in the UV/Vis. spectra when treated with Cu (II) ion as well as with
Pb (II) ion. Ion transportation studies were carried out with cyclophane amide 14 which proved that the NaC ion passes through the cavity
while KC ions are retained.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
and hence, by varying the size of the cavity, cyclic amides
can be used for the transport of a particular ion in preference
to the other ions. Once the synthesis of the targeted cyclic
amide is carried out, the cyclic amide can be impregnated
into a membrane and can be used for ion transport.33
Intramolecular hydrogen bonding can collapse the cyclic
peptide to a minimum accompanied by folding of the
backbone.34 However, due to intermolecular hydrogen
bonding the cyclic amide can show self assembling
properties that would eventually lead to tubular structure
and hence have potential to be used as nano material
devices. Furthermore such cyclic amides can form com-
plexes with metal ions like Cd (II),35 Fe (III)20 and Cu (II)
and hence they can be used for selective metal ion
complexation studies36 and also as a neutral host for anion
complexation.37 Amides are also used as molecular
receptors38 and in the molecular recognition39 of bio-
logically interacting substrates including anti-HIV active
macrocyclic amides.40 With such views in mind we focused
our attention on the synthesis of various cyclic amides.
Herein we report the synthesis and characterization of
various cyclic amides with varied cavity size. Furthermore
we describe herein the ion transport studies of some of the
cyclic amides.
The synthesis of new supramolecules for studying bio-
molecular interactions stimulates the imaginative skill of
synthetic chemists. Synthesis of amide based supra-
molecular system has been reported in the literature.1–17
Cyclic peptides18 with open pores are useful as transport
vehicles for biologically important ions or neutral mole-
cules19 or as catalysts20 and for studying host-guest
chemistry. Synthesis and complexation studies with tyro-
sinophanes has been reported earlier.21 Cystine based cyclic
peptide has the ability to form a double—helical structure.22
The self-assembly of acyclic peptides and hence their ability
to form beta-sheet structures has also been demonstrated.23,24
The conformational aspects and molecular recognition
ability of cystinophanes are well known.25 Adamantane
based systems also form double-helical cyclic structures.24,26
The ability of cyclic peptides to form nanotubes has been
well documented.27,28 Serinophanes form a tubular structure
due to aromatic p–p interactions.29
The ion transport properties of macrocycles are biologically
relevent30 and ion transport through membranes has been
characterized with adamantane based cyclophanes31 and
with norbornene based cyclic peptides.32 Thus cyclic
amides play an important role in various biological systems
2. Results and discussion
Keywords: Cyclophane amides; Adamantane; Macrocyclic amides.
*
Diacid chlorides 1–5 were prepared and used for the
synthesis of cyclophane amides.
Corresponding author. Tel.: C44 2235 1269; fax: C91 44 2235 2494;
e-mail: perumalrajakumar@hotmail.com
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.03.064

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P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
Reaction of catechol with 2.1 equiv of ethyl chloroacetate in
the presence of potassium carbonate followed by the
hydrolysis of the resulting diethyl ester gave the corre-
sponding diacid, which was then reacted with thionyl
chloride to give diacid chloride 1.41 The diacid derived for
diacid chloride 1 was also prepared from the respective
diol.42 Reaction of 4,5-bis (chloromethyl)-o-xylene43 with
2.1 equiv of methyl salicylate followed by hydrolysis of the
resulting dimethyl ester and subsequent reaction with
thionyl chloride gave diacid chloride 2. Diacid chloride 3
was obtained from the corresponding dicarboxylic acid. The
respective dicarboxylic acid was reported earlier44 in 55%
overall yield by the reaction of p-xylylene dibromide with
methyl salicylate in the presence of NaH in THF followed
by hydrolysis. However in the present investigation the
diacid was obtained in 95% overall yield by the alkylation
of p-xylylene dibromide with methyl salicylate in the
presence of anhydrous potassium carbonate and KI in
acetonitrile followed by hydrolysis of the resulting diester.
Reaction of the corresponding dicarboxylic acid with
thionyl chloride in methylene chloride gave diacid chloride
3 in quantitative yield. Diphenic acid chloride 4 was
prepared by the reaction of diphenic acid and thionyl
chloride. The diacid chloride 5 was obtained from the
corresponding diacid which was reported earlier.45 The
diacid was also prepared from 1,3-dibromopropane and
p-hydroxybenzoic acid in presence of NaOH in DMSO.46
By another method, 1,3-dibromopropane was reacted with
methyl p-hydroxybenzoate and the resulting diester was
hydrolyzed to give the dicarboxylic acid.47 In the current
investigation the later method was employed and the
resulting dicarboxylic acid was reacted with thionyl
chloride to give diacid chloride 5.
Diamine 6 has been used previously for polymerization.48
In the earlier method49 1,3-dibromopropane was treated
with p-nitrophenol and the resulting dinitro compound was
then reduced to give diamine 6. In a later method50
1,3-dibromopropane was treated with 4-hydroxy acetanilide
and resulting product was hydrolyzed to give 6. However, in
both the references cited above detailed experimental
procedure was not available as the reported methods were
patented. Hence, in the present investigation 1,3-dibromo-
propane was treated with 2.1 equiv of p-nitrophenol in
acetonitrile in the presence of anhydrous potassium
carbonate and KI and the resulting dinitro compound was
reduced with hydrogen in the presence of Pd/C to give the
diamine 6 in 65% overall yield. Similarly diamine 7 was
also prepared by the reaction of 4,5-bis (chloromethyl)-o-
xylene with p-nitrophenol by the usual procedure to give
dinitro compound, which was reduced with hydrogen in the
presence of Pd/C to give diamine 7. Though diamine 8 was
reported recently,51 in the present investigation 2.1 equiv of
o-aminothiophenol were treated with p-xylylene dibromide
to give diamine 8 in 90% yield. Diamine 9 was also
prepared by a similar method from the reaction of 4,5-bis
(chloromethyl)-o-xylene with o-aminothiophenol.
The diester derived from diacid chloride 1 has been
extensively used for the formation of macrocyclic amides.52
Diacid chloride 1 has been also used for the preparation of
macrocyclic amides.53 Similarly the reaction of diacid
chloride 1 with arylamines has also been studied.54 In the
current investigation, diacid chloride 1 was used for the
synthesis of cyclophane amides. Reaction of diacid choride
1 with o-phenylenediamine (OPDA) in chloroform and in
the presence of triethylamine afforded cyclophane amide 10
in 50% yield. Cyclophane amide 10 in the 1H NMR showed
the OCH2 and NH protons at d 4.76, at d 9.71 in addition to
Diamines 6–9 were prepared and used for the synthesis of
cyclophane amides.

P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
5353
Scheme 1. (a) Triethyl amine, CHCl3, rt, 6 h.
aromatic protons at d 7.04 to 7.63 and in the mass spectrum
the molecular ion appeared at m/z 298. Similarly acid
chloride 1 with various diamines 6, 7, 8 and 9 gave
cyclophane amides 11, 12, 13 and 14 in 45%, 50%, 40% and
45% yield respectively. The reaction sequence is given in
Scheme 1.
appeared as a singlet at d 4.59 and the NH proton appeared
at d 9.55 in addition to the aromatic protons. Compound 12
in the H NMR displayed the aromatic methyl protons at d
2.23 and the two sets of OCH2 protons appeared at d 4.56
and d 5.00 in addition to the aromatic protons. Compound
13 in the 1H NMR displayed the SCH2 and OCH2 protons at
d 3.79 and d 4.55 respectively and the NH protons at d 9.39
in addition to the aromatic protons. In the 1H NMR,
cyclophane 14 displayed signals at d 1.99, d 3.91, d 4.51 and
1
1
Compound 11 in the H NMR displayed the OCH2CH2-
CH2O protons at d 1.83 and d 4.15 and OCH2CO protons
Figure 1. ORTEP diagram for 14.

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P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
d 9.48 for aromatic methyl, SCH2, OCH2 and NH protons,
respectively, in addition to the aromatic protons at d 6.45 to
d 8.39.
In order to synthesize large cavity cyclophanes with amide
linkages diacid chloride 2 was used. In order to test the
suitability of diacid chloride 2 for the formation of
cyclophane, diacid chloride 2 was reacted with o-phenyl-
enediamine and cyclic diamide 15 was obtained in 50%
X-ray diffraction (XRD) studies on cyclophane 1455 showed
the presence of intramolecular hydrogen bonding and hence
cyclophane 14 is not planar and one of the benzene rings is
puckered (Figs. 1 and 2). Though cyclophane 14 can show
self-assembling properties and hence can generate channel,
XRD showed only intramolecular hydrogen bonding rather
than intermoleculer hydrogen bonding.
1
yield. In the H NMR the aromatic methyl, OCH2 and NH
protons appeared at d 2.23, d 5.24 and d 9.64, respectively,
in addition to the aromatic protons. In the mass spectrum the
molecular ion appeared at m/z 478. Similarly reaction of
diacid chloride 2 with diamines 6, 7, 8 and 9 gave
cyclophanes 16, 17, 18 and 19 in 47, 43, 50 and 50%
yield, respectively (Scheme 2).
XRD studies were carried out for cyclophane 15.56 One of
the benzene rings derived from the o-phenylenediamine unit
is orthogonal to the xylenyl unit and the molecule is not
planar due to intramolecular hydrogen bonding and XRD
shows the dimeric structure in crystal packing (Figs. 3
1
and 4). Cyclophane 16 in the H NMR displayed aromatic
methyl and OCH2 protons at d 2.30 and d 5.23. The OCH2
CH2 CH2O protons group appeared at d 1.95 and d 4.08 and
NH protons at d 9.57. Cyclophane 17 in the 1H NMR
displayed two types of aromatic methyl at d 2.22 and d 2.29
and two sets of OCH2 protons appeared at d 5.04 and d 5.38
and the NH protons appeared at d 9.60 in addition to the
aromatic protons. Cyclophane 18 in the 1H NMR displayed
singlet at d 2.21, d 3.94, d 5.01 and d 11.07 for aromatic
methyl, SCH2, OCH2 and NH protons in addition to the
aromatic protons and the molecular ion appeared at m/z 722
in the FAB mass spectrum. Cyclophane amide 19 showed
two types of aromatic methyl protons at d 1.87 and d 2.02
and SCH2, OCH2 and NH protons at d 3.70, d 5.26 and d
1
10.42, respectively, in the H NMR.
Figure 2. Crystal lattice diagram for 14.
Further, we focused attention on the synthesis of cyclophane
Scheme 2. (a) Triethyl amine, CHCl3,rt, 6 h.

P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
5355
Figure 3. ORTEP diagram for 15.
appeared as singlets at d 5.27 and d 9.79 in addition to the
aromatic protons. Cyclophane 22 in the 1H NMR displayed
aromatic methyl, two sets of OCH2 protons and NH protons
at d 2.26, d 5.05, d 5.27 and d 9.80 in addition to the aromatic
protons. Diamide 23 in the 1H NMR displayed SCH2, OCH2
and NH protons at d 3.84, d 5.18 and d 10.58 in addition to
the aromatic protons. Similarly cyclophane amide 24 also
showed aromatic methyl, SCH2, OCH2 and NH protons at d
1.93, d 3.48, d 5.26 and d 10.50 in addition to the aromatic
protons.
It is of interest to use the acid chloride derived from
diphenic acid because biphenyl compounds can show
atropisomerism. With this view, various cyclophane amides
were synthesized from diphenic acid chloride. Diacid
chloride 4 was obtained by the reaction of diphenic acid
with thionyl chloride. Diacid chloride 4 on reaction with
various amines 6, 7, 8 and 9 under the usual condition gave
cyclophane amides 25, 26, 27 and 28 in 40, 44, 40 and 45%
yield, respectively (Scheme 4).
In the mass spectrum cyclophanes 25, 26, 27 and 28
displayed molecular ion at m/z 464 (EI), 554 (EI), 558 (EI)
1
and 586 (EI), respectively. In the H NMR cyclophane 25
showed the OCH2 CH2 CH2O protons at d 1.88 and d 4.10
for two and four protons in addition to the NH protons at d
9.90 and aromatic protons at d 7.30 to d 7.56. A singlet was
observed at d 6.38 for four protons which apparently
indicates that one of the phenyl rings derived from the
amine is orthogonal to the other and due to free rotation all
the four protons of the benzene ring is continuously shielded
in the aromatic p clouds of the other benzene ring and hence
four aromatic protons appear at a different region than the
other aromatic protons. 1H NMR of cyclophane 26
displayed aromatic methyl, OCH2 and NH protons at d
2.27, d 4.88 and d 5.01 (ABq, JZ10.8 Hz) and d
9.32 respectively in addition to the aromatic protons.
As evidenced earlier one of the benzene rings lies
perpendicular to the other and due to shielding effect four
aromatic protons are observed as a doublet at d 6.36 with
JZ9.3 Hz. Cyclophane 27 in the 1H NMR displayed SCH2
protons as an AB quartet at d 3.72 and d 3.92 with JZ
11.7 Hz in addition to the aromatic protons and NH protons
Figure 4. Crystal lattice diagram for 15.
amides based on diacid chloride 3 because of the fact that
the cavity size could still be large due to the p-xylenyl
spacer. Reaction of diacid chloride 3 with p-phenylene-
diamine and diamines 6, 7, 8 and 9 gave cyclophanes 20, 21,
22, 23, and 24 in 45, 42, 48, 50 and 48% yield, respectively
(Scheme 3).
Cyclophane amides 20, 21, 22, 23, and 24 displayed
molecular ions at m/z 450 (EI), 600 (EI), 690 (EI), 694 (FAB
mass spectrum) and 722 (FAB Mass spectrum), respect-
ively. Cyclophane 20 in the 1H NMR displayed singlet at d
5.01 and d 9.61 for OCH2 and NH protons in addition to
aromatic protons. Cyclophane 21 in the 1H NMR displayed
a two-proton quintet at d 2.09 and a four-proton triplet at d
4.17. OCH2 protons at p-xylenyl unit and NH protons

5356
P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
Scheme 3. (a)Triethyl amine, CHCl3, rt, 6 h.
Scheme 4. (a) Triethyl amine, CHCl3,rt, 6 h.
at d 8.46. Similarly, cyclophane 28 in the 1H NMR
displayed aromatic methyl at d 1.99 and SCH2 protons
appeared as an AB quartet at d 3.40 and d 3.56 with JZ
12.7 Hz and the NH protons appeared at d 8.48 in addition to
the aromatic protons.
Finally the utilization of acid chloride 5 for the synthesis of
cyclophane diamide was explored by employing with
o-phenylenediamine. Cyclophane diamide 29 was obtained
in 35% yield by the reaction of acid chloride 5 with
o-phenylenediamine (Scheme 5).
1
In the H NMR compound 29 displayed the OCH2 CH2
CH2O protons at d 1.91 and d 4.20 and the aromatic protons
appeared as an AB quartet at d 6.67 and d 7.47 with JZ
8.8 Hz for eight protons and the aromatic protons derived
from the o-phenylenediamine moiety appeared at d 7.34 as a
broad singlet and the NH protons were observed at d 9.10.
Some of the cyclophanes synthesized were tested for their
complexation behavior with metal ions like copper (II) and
lead (II) as well as for ion transportation studies.
Scheme 5. (a) Triethyl amine, CHCl3, rt, 6 h.

P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
5357
3. X-ray diffraction study
28 in CH3OH, lmax was observed at 235 nm. The shift in
lmax observed by the addition of Cu (II) acetate as well as Pb
(II) acetate in the case of cyclophane amide 28, could be due
to the formation of metal receptor complex. However the
complexes could not be thoroughly characterized, due to
their instability, insolubility in usual NMR solvents and
further because of paramagnetic behavior.
Recrystallisation of the cyclophane 14 in chloroform/
hexane afforded a single crystal suitable for the XRD
studies. The bond lengths and the bond angles have been
reported earlier.55 The crystal parameters are given in
Table 1 and ORTEP diagram as well as crystal lattice
diagram are shown in Figures 1 and 2.
Table 1. Crystal data for cyclophane 14
5. Ion transportation studies
C32H30N2O4S2
MrZ570.70
ZZ2
DxZ1.314 Mg mK3
Mo Ka radiation
Cell parameters from 2732 reflections
qZ2.7–26.38
In the current investigation, a glass vessel as depicted in
Figure 5 was fabricated in order to test the ability of
cyclophane amides towards ion transporting phenomenon.
Though cyclophane amides 14 and 15 do not exhibit self-
assembling characteristics in solid phase as evidenced by
XRD studies, it is of interest to test the ion transport
property in solution phase.
¯
Triclinic, PI
˚
aZ8.5860 (7) A
bZ12.9090 (10) A
cZ14.7552 (11) A
aZ65.065 (1)8
bZ84.701 (1)8
gZ76.522 (1)8
˚
˚
mZ0.23 mmK1
TZ293 (2) K
Needle, colourless
0.25!0.19!0.14 mm
3
˚
VZ1442.1 (2) A
XRD studies proved that intramolecular hydrogen bonding
exists in cyclophane 14 and hence it is not planar though
aromatic rings were introduced to make the molecule
planar.
Similarly XRD studies were carried out with cyclophane 15
after obtaining a crystal from chloroform/methanol and the
crystal parameters are given in Table 2. The ORTEP
diagram and lattice crystal diagram are shown in Figures 3
and 4. Again in cyclophane 15 one of the benzene rings is
orthogonal to the rest of the molecule. XRD studies of
cyclophanes 19 and 23 are currently under investigation.
Figure 5. Apparatus used for ion transport study by cyclophane amide 14.
Cyclophane amide 14 was dissolved in chloroform and kept
in a conical flask fitted with a U tube as shown in Figure 5.
One arm of the U tube is filled with water in which NaCl and
KCl were dissolved and the other arm is filled with triply
distilled water. The chloroform layer was stirred for 5 days.
The arm that was filled with triply distilled water showed
the presence of NaC ion and KC ion level was below the
detecting limit (less than 0.4 mg/l). Thus the experiment
proved that NaC ions were transported by cyclophane
amide 14 from one arm to the other. The size of NaC ion
Table 2. Crystal data for cyclophane 15
C30H26N2O4
MrZ478.53
Monoclinic, P21/n
DxZ1.288 Mg mK3
Mo Ka radiation
Cell parameters from 5463 reflections
qZ2.3–21.78
˚
aZ15.5767 (9) A
mZ0.09 mmK1
˚
bZ15.7746 (9) A
˚
cZ20.5721 (12) A
TZ293 (2) K
Block, colourless
0.24!0.20!0.16 mm
bZ102.541 (1)8
VZ4934.3 (5) A
3
˚
ZZ8
˚
(ionic radius: 0.95 A) and the cavity dimension of
2
cyclophane 14 (4.4!6.1 A ) are complementary to each
Though intermolecular hydrogen bonding could lead to self-
assembling properties, cyclophane 14 and 15 did not exhibit
such properties. Thus from the X- ray diffraction studies, it
is clear that intramolecular hydrogen bonding predominates
over intermolecular hydrogen bonding under solid state
conditions.
˚
other, whereas the size of KC ion (ionic radius: 1.33 A) does
˚
not match with cavity size. Hence cyclophane amide 14
could be used as a potential ion filtering system for retaining
the biologically important KC ion and eliminating NaC ion.
It is noteworthy to mention that KC ion play a vital role in
blood brain barrier. A blank experiment was also performed
in chloroform without cyclophane amide and no such ion
mobility was observed. Currently, we are investigating such
preferential ion mobility of other cyclophane amides.
Further, impregnation of the cyclophane amide 14 on
membrane and ion transport studies over such membranes
are under further investigation.
4. UV/Vis spectral studies
Cyclophane amide 14, 19 and 24 in CH3CN showed lmax in
the UV/Vis. spectrum at 209, 206 and 290, 208 and 287 nm,
respectively. However, no shift in lmax was observed even
after the addition of required amount of either Cu (II)
acetate or Pb (II) acetate to cyclophane amide 14, 19 and 24
in CH3CN. Cyclophane amide 28 shows lmax at 221 nm in
CH3OH in the UV spectrum and after the addition of Cu (II)
acetate, lmax was observed at 273 nm. Similarly when Pb
(II) acetate was added to the solution of cyclophane amide
6. Conclusion
We have synthesized 20 cyclophane diamides, and fully
characterized by spectral, physical and analytical data. XRD

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P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
studies were carried out for cyclophane amides 14 and 15,
which proved the existence of intramolecular hydrogen
bonding. Cyclophane amide 14 shows preference for
transportation of NaC ion over KC ion and hence can be
used as ion filter in biological system.
Elemental analysis calcd for C24H22O6: C, 70.93; H, 5.41.
Found: C, 70.85; H, 5.42. The diacid (0.204 g, 0.5 mmol) in
methylene chloride (25 mL) was refluxed with thionyl
chloride (0.5 mL) and triethylamine (0.1 mL). After reflux-
ing for 2 h, the solvent and excess thionyl chloride were
removed under vacuum to give diacid chloride 2 as a pale
yellow solid.
7. Experimental
7.1. General
7.1.3. Diacid chloride 3. A mixture of p-xylylene
dibromide (2.0 g, 7.5 mmol) methyl salicylate (2.6 g,
17 mmol), anhydrous potassium carbonate (2.5 g,
18 mmol) and KI (0.1 g) in acetonitrile (30 mL) was
refluxed for 8 h. After completion of the reaction, the
reaction mixture was poured into ice water (100 mL). The
precipitated diester was filtered, washed with cold water and
dried as an off-white solid (2.8 g, 90%). Mp 125–127 8C.44
The diester (2.0 g, 4.9 mmol) was treated with ethanolic
KOH (5% w/v, 50 mL). The reaction mixture was filtered
and the clear filtrate was acidified with dil HCl (6 M,
30 mL) to give the diacid, which was filtered with suction
and washed with water. The diacid was dried in vacuum as a
white solid (1.76 g, 95%). Mp 238–240 8C.44 The diacid
(0.189 g, 0.5 mmol), thionyl chloride (0.5 mL) and triethyl-
amine (0.1 mL) in methylene chloride (25 mL) was refluxed
for 2 h. The solvent and excess thionyl chloride were
removed under vacuum to give diacid chloride 3 as a light
brown solid.
1
All H NMR and 13C NMR were recorded in CDCl3 and
DMSO-d6 with JEOL Model: GSX 400. EI-MS spectra were
recorded using JEOL DX-303 mass spectrometer and FAB
MS spectra were recorded using JEOL SX 102/DA-6000
mass spectrometer using a m-nitro benzyl alcohol (NBA)
matrix. Melting points were recorded with Gallenkamp
melting point apparatus. UV/Vis spectra were recorded with
Jasco-V550. FT-IR spectra were recorded with Perkin–
Elmer. Atomic absorption spectra were recorded using
DEP-Vision (model: 381E). Pre-coated silica gel plates
from Merck were used for TLC. Column chromatography
was carried out using silica gel (60–120 mesh) purchased
from Acme.
7.1.1. Diacid chloride 1. A mixture of catechol (11.0 g,
0.10 mol), ethyl chloroacetate (27.0 g, 0.22 mol), anhydrous
potassium carbonate (16.5 g, 0.25 mol) and KI (0.5 g) in
acetonitrile (100 mL) was refluxed for 12 h. After com-
pletion of the reaction, the reaction mixture was poured into
ice water (300 mL) and then added NaOH solution (10%
w/v, 100 mL). The gelatinous precipitate formed was
filtered and the clear filtrate was acidified with dil HCl
(6 M, 150 mL). The precipitated diacid was filtered, washed
with cold water and air dried as an off-white solid (14.7 g,
65%). Mp 179–181 8C.42 A mixture of the diacid (0.113 g,
0.5 mmol), thionyl chloride (0.5 mL) triethylamine
(0.1 mL) in methylene chloride (25 mL) was refluxed for
3 h. The solvent and excess thionyl chloride were removed
under vacuum to give diacid chloride 1 as a light brown
solid.41
7.1.4. Diacid chloride 4. A mixture of diphenic acid
(0.121 g, 0.5 mmol), thionyl chloride (0.5 mL), triethyl-
amine (0.1 mL) and methylene chloride (25 mL) was
refluxed for 2 h. The solvent and excess thionyl chloride
were removed under vacuum to get the diacid chloride 4 as a
light brown solid.
7.1.5. Diacid chloride 5. A mixture of 1,3-dibromopropane
(2.56 g, 12.7 mmol), methyl p-hydroxybenzoate (4.0 g,
26.3 mmol), anhydrous potassium carbonate (4.0 g,
29 mmol) and KI (0.1 g) in acetonitrile (25 mL) was
refluxed for 20 h. The reaction mixture was then poured
into ice water and extracted with methylene chloride (2!
75 mL). The combined organic layer was washed with
NaOH solution (5% w/v, 25 mL) till no methyl p-hydroxy-
benzoate was present and after washing with water (25 mL),
dried over magnesium sulphate. Methylene chloride was
concentrated to 25 mL and cooled with freezing mixture for
3 h. The diester was filtered at suction and dried as an off-
white solid (3.27 g, 75%). Mp 134–136 8C. The diester
(2.0 g, 5.8 mmol) was refluxed with ethanolic KOH (5%
w/v, 50 mL) for 1 h. The reaction mixture was then filtered
and to the clear filtrate dil HCl (6 M, 30 mL) was added to
give the diacid, which was filtered with suction and washed
with water. The diacid was dried in vacuum as a white solid
(1.65 g, 90%). Mp O295 8C.45–47 The diacid (0.158 g,
0.5 mmol) was refluxed in methylene chloride (25 mL) with
thionyl chloride (0.5 mL) and triethylamine (0.1 mL) for
3 h. The solvent and excess thionyl chloride were removed
under vacuum to give the diacid chloride 5 as a light brown
solid.
7.1.2. Diacid chloride 2. A mixture of 4,5-bis (chloro-
methyl)-o-xylene (2.0 g, 9.8 mmol), methyl salicylate
(3.5 g, 23 mmol), anhydrous potassium carbonate (1.3 g,
23 mmol) and KI (0.1 g) in acetonitrile (25 mL) was
refluxed for 8 h. The reaction mixture was cooled to rt and
then quenched into ice water (100 mL) and the solid diester
obtained was filtered with suction. The diester was washed
with cold water and dried with suction as a white solid
(4.2 g, 97%). Mp 121–123 8C; IR (KBr, cmK1) 1732, 1600;
1H NMR (400 MHz, CDCl3) d 2.29 (s, 6H), 3.84 (s, 6H),
5.26 (s, 4H), 6.97–7.81 (m, 10H). Mass spectrum: m/z 434
(MC). Elemental analysis calcd for C26H26O6: C, 71.88; H,
5.99. Found: C, 71.79; H, 5.98. The diester (2.0 g,
4.5 mmol) was treated with ethanolic KOH (5% w/v,
50 mL). The reaction mixture was then filtered and the
clear filtrate was acidified with dil HCl (6 M, 30 mL) to give
the diacid, which was filtered with suction and washed with
water. The diacid was dried in vacuum as a white solid
(1.7 g, 90%). Mp 178–180 8C; IR (KBr, cmK1) 2917, 1695,
7.1.6. Diamine 6. A mixture of 1,3-dibromopropane (2.0 g,
10 mmol), p-nitrophenol (4.0 g, 32 mmol), anhydrous
potassium carbonate (4.0 g, 29 mmol) and KI (0.1 g) in
1
1600; H NMR (400 MHz, CDCl3) d 2.31 (s, 6H), 5.32 (s,
4H), 7.10–8.21 (m, 10H). Mass spectrum: m/z 406 (MC).

P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
5359
acetonitrile (40 mL) was refluxed for 48 h. The reaction
7.2. General procedure for the synthesis of cyclophane
amides
mixture was poured into ice water (100 mL) and made
alkaline with NaOH solution (5% w/v, 25 mL). The solid
dinitro compound was filtered and washed with water (2!
20 mL) and recrystallised from chloroform and hexane (1:1)
to give pure dinitro compound as a pale yellow solid (2.2 g,
80%). Mp 128–130 8C.49 A mixture of dinitro compound
(0.57 g, 2 mmol) and 10% Pd/C (25 mg) in methanol
(100 mL) was warmed to 40 8C and hydrogen gas was
bubbled through the reaction mixture. Immediately after the
completion of the reaction, the reaction mixture was filtered
and the filtrate was concentrated to approximately 10 mL
and cooled to 0–10 8C to give diamine 6 as a beige solid
after washing with cold methanol, (0.41 g, 80%). Mp 109–
111 8C.49,50
A solution of the diacid chloride (0.5 mmol) in dry
chloroform (100 mL) and a solution of the diamine
(0.5 mmol) and triethylamine (1.1 mmol) in dry chloroform
(100 mL) were simultaneously added dropwise to a well-
stirred solution of chloroform (500 mL) during 6 h. After
the addition was complete, the reaction mixture was stirred
for another 6 h. The solvent was removed at reduced
pressure and the residue obtained was then dissolved in
chloroform (300 mL), washed with water (2!100 mL) to
remove the triethylammonium chloride and dried over
magnesium sulphate. Removal of the chloroform gave the
cyclophane as a crude material, which was purified by
column chromatography with suitable eluting solvent as
mentioned under each cyclophane.
7.1.7. Diamine 7. A mixture of 4,5-bis (chloromethyl)-o-
xylene (2.0 g, 10 mmol), p-nitrophenol (3.5 g, 28 mmol),
anhydrous potassium carbonate (4.0 g, 29 mmol) and KI
(0.1 g) in acetonitrile (25 mL) was refluxed for 4 h. Then the
reaction mixture was poured into ice water (100 mL). The
solid was filtered, washed with cold water and dried to give
the dinitro compound as a pale yellow solid in almost pure
7.2.1. Cyclophane 10. White hairy crystalline solid. Eluent
for column chromatography: chloroform to chloroform/
methanol (49:1); yield: 50%; Rf 0.65 (chloroform/methanol,
9:1). Mp 220–222 8C; IR (KBr, cmK1) 3312, 1723, 1676; 1H
NMR (400 MHz, DMSO-d6) d 4.76 (s, 4H), 7.04–7.63 (m,
8H), 9.71 (s, 2H). Mass spectrum: m/z 298 (MC). Elemental
analysis calcd for C16H14N2O4: C, 64.42; H, 4.69; N, 9.39.
Found: C, 64.48; H, 4.68; N, 9.38.
and quantitative yield. Mp 211–213 8C; IR (KBr, cmK1
)
1500, 1330; 1H NMR (400 MHz, DMSO-d6) d 2.25 (s, 6H),
5.30 (s, 4H), 7.16–8.15 (m, 10H). Mass spectrum: m/z 408
(MC). Elemental analysis calcd for C22H20N2O6: C, 64.70;
H, 4.90; N, 6.86. Found: C, 64.59; H, 4.91; N, 6.87. A
mixture of dinitro compound (0.6 g, 1.6 mmol) and 10%
Pd/C (20 mg) in methanol (100 mL) was warmed to 40 8C.
Hydrogen gas was bubbled through the reaction mixture for
1 h. The reaction mixture was filtered and the filtrate was
concentrated to 15 mL. On cooling, diamine 7 crystallized,
which was filtered and washed with cold methanol as a light
7.2.2. Cyclophane 11. Off-white solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(49:1); yield: 45%; Rf 0.55 (chloroform/methanol, 9:1).
1
Mp 238–240 8C; IR (KBr, cmK1) 3375, 1684, 1596; H
NMR (400 MHz, DMSO-d6) d 1.83 (quint, 2H, JZ5.9 Hz),
4.15 (t, 4H, JZ5.9 Hz), 4.59 (s, 4H), 6.57–7.16 (m, 12H),
9.55 (s, 2H). Mass spectrum: m/z 448 (MC). Elemental
analysis calcd for C25H24N2O6: C, 66.96; H, 5.35; N,
6.25.Found: C, 66.89; H, 5.29; N, 6.18.
brown solid (0.5 g, 90%). Mp 190–192 8C; IR (KBr, cmK1
)
1
3425, 1620; H NMR (400 MHz, CDCl3) d 2.25 (s, 6H),
3.25 (br s, 4H) 5.00 (s, 4H), 6.60–7.24 (m, 10H). Mass
spectrum: m/z 348 (MC). Elemental analysis calcd for
C22H24N2O2: C, 75.86; H, 6.89; N, 8.04.Found: C, 75.79; H,
6.88; N, 8.03.
7.2.3. Cyclophane 12. Off-white solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(99:1); yield: 50%; Rf 0.80 (chloroform/methanol, 9:1).
1
Mp 304–306 8C; IR (KBr, cmK1) 3382, 1684, 1597; H
NMR (400 MHz, DMSO-d6) d 2.23 (s, 6H), 4.56 (s, 4H),
5.00 (s, 4H), 6.51–8.04 (m, 14H), 9.22 (s, 2H). Mass
spectrum: m/z 538 (MC). Elemental analysis calcd for
C32H30N2O6: C, 71.37; H, 5.57; N, 5.20.Found: C, 71.42; H,
5.56; N, 5.19.
7.1.8. Diamine 8. To a solution of KOH (1.3 g, 19.7 mmol)
in methanol (40 mL) was added o-aminothiophenol (2.4 g,
19.2 mmol) followed by p-xylylene dibromide (2.0 g,
7.5 mmol) at 30 8C with stirring. After stirring for 2 h, the
solid obtained was filtered with suction and washed with
methanol (25 mL). Then the solid was washed with water
(50 mL) and dried with suction to give pure diamine 8,
brown solid (2.4 g, 90%). Mp 141–143 8C.51
7.2.4. Cyclophane 13. Lemon yellow solid. Eluent for
column chromatography: hexane to hexane/chloroform
(1:1); yield: 40%; Rf 0.55 (toluene/ethyl acetate, 9:1). Mp
1
204–208 8C; IR (KBr, cmK1) 3350, 1684, 1577; H NMR
(400 MHz, CDCl3) d 3.79 (s, 4H), 4.55 (s, 4H), 6.86–8.46
(m, 16H), 9.39 (s, 2H); 13C NMR (100.4 MHz, CDCl3) d
29.9, 43.0,70.2, 117.5, 120.5, 123.4, 124.1, 125.1, 129.3,
130.7, 136.6, 136.8, 140.0, 148.6, 166.5. Mass spectrum:
m/z 542 (MC). Elemental analysis calcd for C30H26N2O4S2:
C, 66.42; H, 4.79; N, 5.16. Found: C, 66.37; H, 4.78; N,
5.17.
7.1.9. Diamine 9. To a solution of KOH (1.3 g, 19.7 mmol)
in methanol (40 mL) was added o-aminothiophenol (2.4 g,
19.2 mmol) followed by 4,5-bis (chloromethyl)-o-xylene
(1.52 g, 7.5 mmol) at 30 8C with stirring. After stirring for
8 h, the solid obtained was filtered with suction, washed
with methanol (10 mL), then with water (50 mL) and dried
to give diamine 9 as a light violet solid (2.3 g, 80%). Mp
129–131 8C; IR (KBr, cmK1) 3444, 1604; 1H NMR
(400 MHz, CDCl3) d 2.14 (s, 6H), 3.92 (s, 4H), 4.30 (br s,
4H), 6.61–7.26 (m, 10H). Mass spectrum: m/z 380 (MC).
Elemental analysis calcd for C22H24N2S2: C, 69.47; H, 6.31;
N, 7.36. Found: C, 69.39; H, 6.32; N, 7.35.
7.2.5. Cyclophane 14. Off-white crystalline solid. Eluent
for column chromatography: hexane to hexane/chloroform
(1:1); yield: 45%; Rf 0.60 (toluene/ethyl acetate, 9:1). Mp
1
226–228 8C; IR (KBr, cmK1) 3378, 1685, 1595. H NMR

5360
P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
(400 MHz, CDCl3) d 1.99 (s, 6H), 3.91 (s, 4H), 4.51 (s, 4H),
6.45–8.39 (m, 14H), 9.48 (s, 2H); 13C NMR (100.4 MHz,
CDCl3) d 19.0, 38.5, 68.8, 113.9, 120.2, 122.8, 123.5, 124.6,
129.9, 131.0, 131.8, 135.3, 136.2, 139.2, 147.2, 166.2. Mass
spectrum: m/z 570 (MC). Elemental analysis calcd for
C32H30N2O4S2; C, 67.36; H, 5.26; N, 4.91.Found; C, 67.31;
H, 5.27; N, 4.92.
Elemental analysis calcd for C46H42N2O4S2: C, 73.6; H,
5.60; N, 3.73. Found: C, 73.65; H, 5.55; N, 3.78.
7.2.11. Cyclophane 20. Off-white solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(99:1); yield: 45%; Rf 0.62 (chloroform/methanol, 9:1).
Mp 268–270 8C (decomp.); IR (KBr, cmK1) 3333, 1702,
1654, 1601; 1H NMR (400 MHz, DMSO-d6) d 5.01 (s, 4H),
7.09–8.26 (m, 16H), 9.61 (s, 2H). Mass spectrum: m/z 450
(MC). Elemental analysis calcd for C28H22N2O4: C, 74.66;
H, 4.88; N, 6.22. Found: C, 74.71; H, 4.73; N, 6.30.
7.2.6. Cyclophane 15. Beige crystalline solid. Eluent for
column chromatography: chloroform to chloroform/metha-
nol (99:1); Yield: 50%; Rf 0.75 (chloroform/methanol, 9:1).
1
Mp 278–281 8C; IR (KBr, cmK1) 3353, 1663, 1597; H
7.2.12. Cyclophane 21. White crystalline solid. Eluent for
column chromatography: chloroform to chloroform/metha-
nol (49:1); yield: 42%; Rf 0.84 (chloroform/methanol, 9:1).
NMR (400 MHz, CDCl3) d 2.23 (s, 6H), 5.24 (s, 4H), 6.91–
8.21 (m, 14H), 9.64 (s, 2H); 13C NMR (100.4 MHz, CDCl3)
d 19.4, 29.6, 70.4, 112.8,121.6, 121.8, 124.3, 125.1, 129.7,
131.4, 132.2, 132.9, 133.1, 138.2, 156.3, 163.8. Mass
spectrum: m/z 478 (MC). Elemental analysis calcd for
C30H26N2O4: C, 75.31; H, 5.44; N, 5.85. Found: C, 75.39;
H, 5.45; N, 5.86.
1
Mp 251-253 8C; IR (KBr, cmK1) 3354, 1663, 1597; H
NMR (400 MHz, DMSO-d6) d 2.09 (quint, 2H, JZ5.8 Hz),
4.17 (t, 4H, JZ5.8 Hz) 5.27 (s, 4H), 6.80–8.18 (m, 20H),
9.79 (s, 2H). Mass spectrum: m/z 600 (MC). Elemental
analysis calcd for C37H32N2O6: C, 74.0; H, 5.33; N, 4.66.
Found: C, 73.8; H, 5.29; N, 4.72.
7.2.7. Cyclophane 16. White solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(99:1); yield: 47%; Rf 0.80 (chloroform/methanol, 9:1).
7.2.13. Cyclophane 22. White solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(49:1); yield: 48%; Rf 0.86 (chloroform/methanol, 9:1).
Mp 292-294 8C; IR (KBr, cmK1) 3348, 1663, 1597, 1542;
1H NMR (400 MHz, DMSO-d6) d 2.26 (s, 6H), 5.05 (s, 4H),
5.27 (s, 4H), 6.86–8.14 (m, 22H), 9.80 (s, 2H); FAB Mass
spectrum: m/z 690 (MC). Elemental analysis calcd for
C44H38N2O6: C, 76.52; H, 5.50; N, 4.05. Found: C, 76.65;
H, 5.48; N, 4.07.
1
Mp 234–236 8C; IR (KBr, cmK1) 3340, 1658, 1598; H
NMR (400 MHz, CDCl3) d 1.95 (quint, 2H, JZ5.8 Hz),
2.30 (s, 6H), 4.08 (t, 4H, JZ5.8 Hz), 5.23 (s, 4H), 6.44–8.06
(m, 18H), 9.57 (s, 2H); FAB Mass spectrum: m/z 628 (MC).
Elemental analysis calcd for C39H36N2O6: C, 74.52; H,
5.73; N, 4.45. Found: C, 74.57; H, 5.78; N, 4.44.
7.2.8. Cyclophane 17. Off-white solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(99:1); yield: 43%; Rf 0.75 (chloroform/methanol, 9:1).
Mp O300 8C; IR (KBr, cmK1) 3348, 1662, 1598; 1H NMR
(400 MHz, DMSO-d6) d 2.22 (s, 6H), 2.29 (s, 6H), 5.04 (s,
4H), 5.38 (s, 4H), 6.57–8.10 (m, 20H), 9.60 (s, 2H); FAB
Mass spectrum: m/z 718 (MC). Elemental analysis calcd for
C46H42N2O6: C, 76.88; H, 5.84; N, 3.89. Found: C, 76.94;
H, 5.77; N, 3.81.
7.2.14. Cyclophane 23. Off-white crystalline solid. Eluent
for column chromatography: hexane to hexane/chloroform
(1:1); yield: 50%; Rf 0.66 (toluene/ethyl acetate, 9:1). Mp
1
200–202 8C; IR (KBr, cmK1) 3335, 1665, 1595, 1576; H
NMR (400 MHz, CDCl3) d 3.84 (s, 4H), 5.18 (s, 4H), 6.85–
8.53 (m, 24H), 10.58 (s, 2H); 13C NMR (100.4 MHz,
CDCl3) d 40.3, 71.2, 113.6, 121.7, 121.8, 122.6, 124.3,
124.8, 127.2, 128.7, 128.8, 132.5, 132.9, 133.1, 135.6,
136.0, 139.1, 156.6, 163.6; FAB Mass spectrum: m/z 694
(MC). Elemental analysis calcd for C42H34N2O4S2: C,
72.62; H, 4.89; N, 4.03. Found: C, 72.55; H, 4.79; N, 4.10.
7.2.9. Cyclophane 18. Off-white solid. Eluent for column
chromatography: hexane to hexane/chloroform (1:1); yield:
50%; Rf 0.50 (toluene/ethyl acetate, 9:1). Mp 254–256 8C
1
(decomp.); IR (KBr, cmK1) 3291, 1658, 1581; H NMR
7.2.15. Cyclophane 24. Light brown crystalline solid.
Eluent for column chromatography: hexane to hexane/
chloroform (1:1); yield: 48%; Rf 0.52 (toluene/ethyl acetate,
9:1). Mp 202-204 8C; IR (KBr, cmK1) 3279, 1668, 1576; 1H
NMR (400 MHz, CDCl3) d 1.93 (s, 6H), 3.48 (s, 4H), 5.26
(s, 4H), 6.35–8.54 (m, 22H), 10.50 (s, 2H); 13C NMR
(100.4 MHz, CDCl3) d 19.0, 37.0, 70.9, 112.7, 121.6, 121.7,
122.6, 123.7, 124.2, 128.0, 129.0, 131.8, 132.5, 132.8,
133.2, 134.3, 135.5, 136.2, 139.6, 156.5, 163.5; FAB Mass
spectrum: m/z 722 (MC). Elemental analysis calcd for
C44H38N2O4S2: C, 73.13; H, 5.26; N, 3.87. Found: C, 73.19;
H, 5.18; N, 3.89.
(400 MHz, CDCl3) d 2.21 (s, 6H), 3.94 (s, 4H), 5.01 (s, 4H),
6.68–8.69 (m, 22H), 11.07 (s, 2H); 13C NMR (100.4 MHz,
CDCl3) d 19.9, 41.6, 69.4, 114.9, 122.3, 122.7, 123.6, 124.8,
125.4, 129.0, 129.6, 131.1, 133.4, 133.8, 137.1, 137.2,
140.4, 157.1, 164.2; FAB Mass spectrum: m/z 722 (MC).
Elemental analysis calcd for C44H38N2O4S2: C, 73.13; H,
5.26; N, 3.87. Found: C, 72.95; H, 5.20; N, 3.91.
7.2.10. Cyclophane 19. Off-white solid. Eluent for column
chromatography: hexane to hexane/chloroform (1:1); yield:
50%; Rf 0.70 (toluene/ethyl acetate, 9:1). Mp 224–227 8C;
1
IR (KBr, cmK1) 3337, 1661, 1600; H NMR (400 MHz,
CDCl3) d 1.87 (s, 6H), 2.02 (s, 6H), 3.70 (s, 4H), 5.26 (s,
4H), 6.48–8.53 (m, 20H), 10.42 (s, 2H); 13C NMR
(100.4 MHz, CDCl3) d 18.8, 19.2, 38.3, 69.8, 113.7,
121.5, 121.9, 123.6, 123.8, 124.3, 129.4, 130.4, 131.3,
131.7, 132.4, 132.8, 132.9, 135.1, 135.9, 137.3, 140.2,
156.7, 163.8; FAB Mass spectrum: m/z 750 (MC).
7.2.16. Cyclophane 25. White crystalline solid. Eluent for
column chromatography: chloroform to chloroform/metha-
nol (99:1); yield: 40%; Rf 0.72 (chloroform/methanol, 9:1).
Mp 300–304 8C; IR (KBr, cmK1) 3343, 2940, 1668, 1532;
1H NMR (400 MHz, DMSO-d6) d 1.88 (quint, 2H, JZ
5.8 Hz), 4.10 (t, 4H, JZ5.8 Hz), 6.38 (s, 4H), 7.30–7.56 (m,

P. Rajakumar, A. M. A. Rasheed / Tetrahedron 61 (2005) 5351–5362
5361
12H), 9.90 (s, 2H). Mass spectrum: m/z 464 (MC).
Elemental analysis calcd for C29H24N2O4: C, 75.0; H,
5.17; N, 6.03. Found: C, 75.07; H, 5.11; N, 6.10.
(0.0234 g) dissolved in methanol (50 mL) displayed absorp-
tion at 222 nm. By adding Cu (II) acetate (0.008 g, 4!10K2
mmol) to the cyclophane amide 28 (0.0234 g, 4!10K2
mmol) new absorption maximum were observed at 209 and
273 nm and similarly by adding Pb (II) acetate (0.0117 g,
4!10K2 mmol) lmax was observed at 235 nm.
7.2.17. Cyclophane 26. White solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(99:1); yield: 44%; Rf 0.54 (chloroform/methanol, 9:1).
1
Mp 316–318 8C; IR (KBr, cmK1) 3433, 1681, 1530; H
7.4. Ion transportation studies
NMR (400 MHz, DMSO-d6) d 2.27 (s, 6H), 4.88, 5.01
(ABq, 4H, JZ10.8 Hz), 6.36 (d, 4H, JZ9.3 Hz), 7.18–7.62
(m, 14H), 9.32 (s, 2H); 13C NMR (100.4 MHz, DMSO-d6) d
18.2, 77.9, 78.2, 114.5, 119.7, 126.2, 127.0, 129.0, 132.1,
132.4, 133.2, 135.6, 139.7, 155.0, 168.8. Mass spectrum:
m/z 554 (MC). Elemental analysis calcd for C36H30N2O4: C,
77.97; H, 5.41; N, 5.05. Found: C, 77.89; H, 5.38; N, 5.12.
A solution of cyclophane amide 14 (65 mg, 11.4!10K2
mmol) in chloroform (40 mL) was kept in a conical flask
fitted with a U tube (Fig. 5). A solution of NaCl (585 mg,
10 mmol) and KCl (745 mg, 10 mmol) in triply distilled
water (10 mL) was kept in one arm of the U tube and the
other arm was filled with triply distilled water (10 mL).
After properly stoppering the arms of the U tube, the
chloroform layer was stirred vigorously for 5 days. The arm,
which was filled with triply distilled water showed the
presence of NaCl (21.1 mg/l) and KC ion level was below
the detecting limit (less than 0.40 mg/l).
7.2.18. Cyclophane 27. Pale yellow solid. Eluent for
column chromatography: hexane to hexane:chloroform
(1:1); yield: 40%; Rf 0.48 (toluene/ethyl acetate, 9:1). Mp
1
220–224 8C; IR (KBr, cmK1) 3352, 1666, 1577; H NMR
(400 MHz, CDCl3) d 3.72, 3.92 (ABq, 4H, JZ11.7 Hz),
6.77 (s, 4H), 7.02–8.02 (m, 16H), 8.46 (s, 2H); 13C NMR
(100.4 MHz, CDCl3) d 41.4, 121.9, 125.0, 125.8, 127.4,
128.3, 128.4, 128.6, 130.1, 130.3, 135.6, 136.5, 138.6,
139.9, 166.9. Mass spectrum: m/z 558 (MC). Elemental
analysis calcd for C34H26N2O2S2: C, 73.11; H, 4.65; N,
5.01. Found: C, 73.20; H, 4.61; N, 5.10.
Acknowledgements
The authors thank DST, CSIR, New Delhi for financial
assistance, UGC SAP for facility provided to the Depart-
ment and SAIF, Madras, for NMR spectra and RSIC, CDRI,
Lucknow for FAB MS. A.R. thanks Amrutanjan Ltd. for all
the help.
7.2.19. Cyclophane 28. Off-white solid. Eluent for column
chromatography: hexane to hexane:chloroform (1:1); yield:
45%; Rf 0.46 (toluene/ethyl acetate, 9:1). Mp 226–228 8C;
1
IR (KBr, cmK1) 3321, 1670, 1577; H NMR (400 MHz,
CDCl3) d 1.99 (s, 6H), 3.40, 3.56 (ABq, 4H, JZ12.7 Hz),
6.39 (s, 4H), 6.83–8.38 (m, 14H), 8.48 (s, 2H); 13C NMR
(100.4 MHz, CDCl3) d 19.0, 37.9, 119.5, 121.9, 123.9,
128.2, 129.3, 129.8, 130.3, 130.8, 130.9, 131.3, 135.2,
135.9, 136.3, 136.9, 140.0, 167.6. Mass spectrum: m/z 586
(MC). Elemental analysis calcd for C36H30N2O2S2: C,
73.72; H, 5.11; N, 4.77. Found: C, 73.68; H, 5.08; N, 4.81.
References and notes
1. Luening, U. Liebigs Ann. Chem. 1987, 11, 949–955.
2. Dirk, L.; Atzrodt, J.; Rainer, B.; Helmar, G. Liebigs Ann. 1994,
1, 199–201.
3. Jingsong, Y.; Xiaoqi, Y.; Changlu, L.; Rugang, X. Synth.
Commun. 1999, 29, 2447–2455.
7.2.20. Cyclophane 29. White solid. Eluent for column
chromatography: chloroform to chloroform/methanol
(99:1); yield: 35%; Rf 0.66 (chloroform/methanol, 9:1).
Mp 296–298 8C; IR (KBr, cmK1) 3242, 1646, 1603, 1522;
1H NMR (400 MHz, DMSO-d6) d 1.91 (quint, 2H, JZ
5.3 Hz), 4.20 (t, 4H, JZ5.3 Hz), 6.67, 7.47 (ABq, 8H, JZ
8.8 Hz), 7.34 (br s, 4H), 9.10 (s, 2H). Mass spectrum: m/z
388 (MC). Elemental analysis calcd for C23H20N2O4: C,
71.13; H, 5.15; N, 7.25. Found: C, 71.09; H, 5.10; N, 7.29.
4. Thomas, R. W.; Yuan, F.; Cynthia, J. B. J. Org. Chem. 1989,
54, 1584–1589.
5. Yukito, M.; Junichi, K.; Hiroaki, T. J. Chem. Soc., Chem.
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