Synthesis and characterisation of asymmetrically bridged calix[4]arene and tetrathiacalix[4]arene mono amido crown derivatives

Article abstract of DOI:10.3184/030823410X12779951975025

The synthesis of asymmetrically bridged calix[4]arene and tetrathiacalix[4]arene amido crown derivatives has been achieved by the aminolysis of distal diester derivatives of calix[4]arene and tetrathiacalix[4]arene with 1,2-diaminopropane or 1,2-diaminocyclohexane (stereoisomeric mixture, mainly trans). The title compounds have been characterised by detailed analysis of their NMR spectra. The assignment of NMR signals and stereo differentiation in the amido crown ring formation has been studied using a chiral shift reagent.

Full text of DOI:10.3184/030823410X12779951975025

JOURNAL OF CHEMICAL RESEARCH 2010
JULY, 375–378
RESEARCH PAPER 375
Synthesis and characterisation of asymmetrically bridged calix[4]arene
and tetrathiacalix[4]arene mono amido crown derivatives
Harmohinder Chawla*, Nalin Pant, Satish Kumar and Suneel Pratap Singh
Department of Chemistry, Indian Institute ofTechnology, Hauz Khas, New Delhi-110016, India
The synthesis of asymmetrically bridged calix[4]arene and tetrathiacalix[4]arene amido crown derivatives has been
achieved by the aminolysis of distal diester derivatives of calix[4]arene and tetrathiacalix[4]arene with 1,2-diamino-
propane or 1,2-diaminocyclohexane (stereoisomeric mixture, mainly trans). The title compounds have been charac-
terised by detailed analysis of their NMR spectra. The assignment of NMR signals and stereo differentiation in the
amido crown ring formation has been studied using a chiral shift reagent.
Keywords: calixarene, thiacalixarene, calixamidocrowns, calixazacrowns, chiral shift reagents
Calixarenes are phenolic macrocyclic molecules which have
been extensively used to design symmetrical and asymmetrical
scaffolds for obtaining molecular receptors for recognition of
groups. FAB-MS spectra of 3a–d exhibited molecular ion
+
peaks (M +1) at 803 (for 3a), 579 (for 3b), 875 (for 3c),
651 (for 3d), 843 (for 4a) and 619 (for 4b) respectively which
unambiguously confirmed the formation of mono amido crown
derivatives.
1
–8
cations, anions and molecules. Realisation of chiral calix-
arenes (with chirality principles embedded within the calix-
arene scaffold or outside of it) is extremely important both
Alhough the symmetrically bridged amido crown analogues
(5a, b, Fig. 1) show much simpler NMR spectral pattern i.e., a
pair of doublet for methylene bridge protons as shown in our
9
,10
from the view point of resolution of racemic mixtures. as
well as recognition of anions which unlike cations are present
in various symmetrical and asymmetrical shapes. Asymmetri-
cal calixarene derivatives are important for achieving the
complementarity of shape of the anions and the molecular
receptors.
1
7
previous publication. The NMR spectra of apparently asym-
metrically bridged amido crown analogues (3a–d) were more
difficult to interpret. The similarity of splitting pattern of their
1
HNMRspectrawiththoseofotherasymmetricalcalix[4]arenes
provided clues to the presence of chiral unit in these mole-
Several strategies have been used to achieve asymmetrical
calixarenes. These strategies include the introduction of chiral
substituents in the calixarene skeleton, desymmetrisation of
basic calixarene cage through different substitutents at the
lower or the upper rim as well as through the less explored
approach that involves the incorporation of a substituent in the
1
8,19
cules.
Asymmetrically bridged calix[4]arene amido crown
derivatives (3a, 3b, 4a, 4b) gave two signals for methylene
1
3
carbons in the range of δ 29–32 ppm in C NMR spectra which
2
0–22
suggest that they exist in their cone conformation
thereby
indicating the introduction of asymmetry in the amido crown
ring. For example, methylene bridge protons in 3a appeared
as six doublets (2:2:1:1:1:1) at δ 4.28, 4.03, 3.57, 3.53, 3.42
1
1–13
meta position of phenol ring of calixarenes.
arenes undergo rapid conformational change, establishment of
Since calix-
and 3.38 respectively. The –OCH protons merged with signals
1
4,15
2
asymmetry in calixarenes is a complex issue.
Very little
for one proton of –NHCH(CH )– and appeared as a triplet and
3
work seems to have been published on the characterisation of
inherently asymmetric calix[4]arene derivatives. In fact, char-
acterisation of asymmetrical calixarene derivatives becomes
more difficult in the presence of enantiomeric mixtures of
substrates or the recognition targets.
a pair of doublets (1:1) at δ 4.68, 4.49 and 4.42. Similarly, both
the distereotopic protons of –NHCH – appeared at different
2
places as broad doublets at δ 4.17 and 3.24. (Fig. S1, see
Electronic Supplementary Information, ESI)
1
A similar H NMR pattern was observed for the debutylated
Despite the importance of asymmetrical (thia)calixarenes
and calixarene–amidocrown compounds, (useful calixarene
derivatives for recognition of anions), it is significant that there
has been only one report on the subject. The reported work
involves a multistep synthetic route which provides asym-
analogue (3b) (Fig. S2, see ESI), while in the DEPT-135
spectrum, it exhibited six signals for the aromatic –CH and
two signals for methylene carbon to suggest its asymmetric
structure. The NMR signals were assigned with the help of
HSQC (Fig. S3, see ESI) and DQF-COSY spectrum (Fig. S4,
see ESI).
1
6
metric calixarene amido crown compounds in low yields. On
the other hand, there seems to be no precedent in the literature
for the synthesis of asymmetrically bridged tetrathiacalix
1
1
It was determined that the two-dimensional H– H correla-
tions are extremely helpful in determining the molecular struc-
ture of 3b as shown in Fig. S4 (ESI). The NMR spectrum of
tetrathiacalix[4]arene mono amido crown derivatives 3c and
3d were found to be similar to their calix[4]arene analogues.
The tetrathiacalix[4]arene mono-amido crown derivatives
therefore were inferred to be present in their cone conforma-
tion with a chiral centre in the amide ring. For instance, com-
pound 3c exhibited prominent NMR signals at δ 8.83 and 8.71
for hydroxyl protons and at δ 8.34 and 8.00 for amide protons
while signals for aromatic protons appeared at δ 7.66, 7.61 and
(
amido) crown derivatives.
We report here an easy, high yield synthesis and characteri-
sation of inherently asymmetrically bridged tetrathiacalix[4]
arene and calix[4]arene amido crown derivatives through
aminolysis of diester derivatives of tetrathiacalix[4]arene and
calix[4]arene.
Results and discussion
The products of the reaction (Scheme 1) were identified by the
7
4
.50 (1:1:2). The ArOCH – protons appeared at δ 4.82 (t, 2H),
1
13
2
analysis of their IR, H and C NMR spectra, FAB MS and
CHN analysis. The substitution at both the ester groups could
be confirmed by disappearance of characteristic absorptions
.51 (d, 1H) and 4.35(d, 1H) while NHCH protons appeared
2
at δ 4.18 and δ 3.26 respectively. The (CH ) C- protons
3
3
appeared at δ 1.18 and δ 1.11 while –CH and –NHCH(CH )–
3
3
−
1
for the ester groups around 1750–1775 cm in the IR spectra.
The synthesised amides showed characteristic absorptions for
appeared at δ 1.26 and δ 4.57 respectively. The complicated
NMR spectral pattern observed could be interpreted with
the help of NOESY spectral analysis (Fig. S5a, see ESI). The
molecular structure assigned on the basis of NOESY correla-
tions of tetrathiacalix[4]arene mono amido crown constitution
−
1
−1
–
C(=O)–N– (1660–1680 cm ) and –N–H (3320–3330 cm )
*
Correspondent. E-mail: hmchawla@chemistry.iitd.ac.in

3
76 JOURNAL OF CHEMICAL RESEARCH 2010
Scheme 1 Synthesis of asymmetrically bridged calix[4]arene mono amido crowns analogues (3a–d, 4a–b).
1
3
as represented in Fig. S5b (ESI) was further confirmed by C
NMR spectrum (DEPT-135) of 3c (Fig S5b, see ESI).
into six singlets (1:1:1:1:2:2 ratio) along with significant
downfield shifts on addition of chiral shift reagent (Fig. 2).
The appearance of six singlets for tert-butyl protons in
1:1:1:1:2:2 ratio could be attributed to the existence of two
enantiomers, each having three different kinds of tert-butyl
groups in 1:1:2 ratio (Fig. S3, ESI). The integration ratios of
the protons also substantiated the results obtained from the
optical rotation studies which confirmed the presence of two
enantiomers in an almost equimolar ratio. The other protons in
3a also showed significant downfield shifts in the NMR exper-
iment on addition of the shift reagent. Similar observations
could be discerned with 3c. However, in the case of their debu-
tylated analogues (3b and 3d), complicated splitting pattern
with significant downfield shifts could be observed in similar
experiments. Due to the absence of tert-butyl groups in this
case, we were unable to find characteristic signals for analysis
of the splitting pattern but on the basis of their structural simi-
larity with the tert-butyl analogue, we expect them to be a
The NMR spectra of 4a and 4b gave a series of multiplets as
given in the experimental section. The compounds clearly gave
signals for methylene carbons in the range of δ 29–32 ppm in
the C NMR spectra which suggested that they are present in
their cone conformation. The FAB MS and elemental analysis
established them to be calix[4]arene mono amido crown
compounds.
The aminolysis of calix[4]arene or tetrathiacalix[4]arene
diethyl acetate, in principle, can lead to the formation of
biscalixarenes due to the reaction of two terminal amino group.
However, no trace of bis-calix[4]arenes or bis-tetrathiacalix[4]
arenes could be detected.
13
1
The H NMR spectral analysis with the help of a chiral shift
reagent ytterbium(III) tris [3-(trifluoromethyl-hydroxylmeth-
ylene)-(e)-camphorato] revealed that tert-butyl protons of 3a
which initially appeared as two singlets (1:1 ratio) got split

JOURNAL OF CHEMICAL RESEARCH 2010 377
most stable amido crown compounds (mainly trans). Further
investigation to use them for resolution of target organic
racemates and anion recognition for development of sensor
materials is being undertaken in our laboratories.
Experimental
All the reagents used in the study were purchased from Sigma-Aldrich,
Alpha Aesar, or Merck and were considered chemically pure. The sol-
vents used were distilled. Column chromatography was performed on
1
silica gel (60–120 mesh) obtained from Merck. H NMR, DQF-COSY,
13
NOESY, C NMR, DEPT-135 and HSQC spectra were recorded on
a 300 MHz Bruker DPX 300 instrument at room temperature using
tetramethylsilane (TMS) at 0.00 as an internal standard. IR spectra
were recorded on a Nicolet Protégé 460 spectrometer in KBr disks
while the FAB mass spectra were recorded on a JEOL SX 102/
DA-6000 Mass spectrometer/Data System using Argon/Xenon (6 kV,
10mA) as the FAB gas. Melting points were determined on an electro-
thermal melting point apparatus obtained from M/S Toshniwal and
were uncorrected. Elemental analyses were carried out on a Perkin
Elmer’s 240C-CHN analyser.
Preparation of starting materials
p-tert-Butylcalix[4]arene 1a and p-tertbutyltetrathiacalix[4]arene 1c
were obtained by base catalysed condensation of p-tert-butylphenol
with formaldehyde or sulfur as reported previously.
Fig. 1 Molecular structure of a symmetrically bridged calix[4]
arenemono amido crown analogues.17
26,27
Their debutyl-
ated analogues (1b, 1d) were obtained by the AlCl catalysed dealkyl-
3
28,29
ation reaction.
The synthesis of diester derivatives (2a–d) was
achieved by the reaction of bromoethylacetate in the presence of
30,31
potassium carbonate (for 2a and 2b)
and 2d).
or sodium carbonate (for 2c
32
Synthesis of calix[4]arene (amido)mono-crown derivatives; general
procedure
Diesters (2a, 2b, 2c and 2d) and 1,2-diaminopropane or trans-1,2-
diaminocyclohexane (20–30 equiv.) were refluxed in toluene: ethanol
(
1:1 ratio) for 48–72 h. The solvent was removed under reduced pres-
sure to yield a yellowish semisolid (or solid) which was recrystallised
twice from CHCl :CH OH to yield calix[4]arene amido mono crown
3
3
derivatives as white solids that were further purified by column
chromatography if necessary (for 3c and 3d).
1
,3-Distal-5,11,17,23-tetra-tert-butyl-25,27-(5-methyl-3,8-dioxo-
1
,10-dioxa-4,7-diazadecano)calix[4]arene (3a): White solid, yield:
−1
7
4%, m.p. > 200 °C (decomposed). IR (KBr, υmax/ cm ): 3373, 1695.
1
H NMR (300 MHz, CDCl , δ in ppm): 8.31 (d, 1H, J = 7.5 Hz,
3
–
CONH), 8.27 (s, 1H, –OH), 8.23 (s, 1H, –OH), 8.22 (d, 1H, J = 7.5
Hz, –CONH), 7.14 (s, 1H, ArH), 7.12 (s, 2H, ArH), 7.04 (s, 2H, ArH),
7
.01 (s, 1H, ArH), 6.98 (s, 2H, ArH), 4.68 (t, 3H, ArOCH and
2
CONHCH(CH )CH NHCO ), 4.49 (dd, 2H, J = 14.1 Hz, 6.6 Hz,
3
2
1
Fig. 2 Partial H NMR spectrum (298 K, 300 MHz) of 3a showing
ArOCH ), 4.28 (d, 2H, J = 11.7 Hz, ArCH Ar), 4.22 (d, 1H, J = 13.2
2
2
splitting in tert-butyl protons on the addition of chiral shift
Hz, CONHCH(CH )CH NHCO), 4.03 (d, 2H, J = 11.1 Hz, ArCH Ar),
3 2 2
reagent
ytterbium(III)
tris
[3-(trifluoromethyl-hydroxyl-
3.57 (d, 1H, J = 7.5 Hz, ArCH Ar), 3.53 (d, 1H, J = 7.5 Hz, ArCH Ar),
2
2
methylene)-(e)-camphorato] derivative (a) after 2 minutes; (b)
after 2 hours; and (c) after 2 days.
3.42 (d, 1H, J = 5.7 Hz, ArCH Ar), 3.38 (d, 1H, J = 5.7 Hz, ArCH Ar),
2 2
3.24 (broad d, 1H, J = 13.5 Hz, CONHCH(CH )CH NHCO), 1.31
3
2
(
–
t, 3H, J = 7.2 Hz, –CH ), 1.24 (s, 18H, –C(CH ) ), 1.13 (s, 18H,
C(CH ) ). DEPT-135 NMR (75 MHz, CDCl , δ in ppm): 127.3,
3 3 3
3
3
3
racemic mixture of two enantiomers. The addition of H O or
D O to the complex formed between the chiral shift reagent
2
2
126.5, 126.3, 126.2, 126.1 (aromatic CH), 74.8 (ArOCH ), 45.0
2
(NHCH), 43.6 (NHCH ), 32.9 (ArCH Ar), 31.97, 31.50 (–C(CH ) ),
2
2
3 3
and calix[4]arene amido crown derivative in CDCl resulted in
17.68 (–CH ). FAB MS m/z: 803 (M++1, 100%). Anal. Calcd for
3
3
a spectrum similar to the free calix[4]arene amido crown, i.e.,
two signals for the tert-butyl groups of 3a. This observation
indicated that the formation of a complex between the chiral
shift reagent and calixarene amido crown is a reversible
process and the complexation requires anhydrous conditions to
choose appropriate stereoisomer for cyclisation and to limit
numerous conformational possibilities to yield the most stable
amido crown compounds.
In conclusion, we have observed that special disposition
of amino groups in calix[4]arene and tetrathiacalix[4]arene
can induce cyclisation to give chiral calix[4]arene- and
tetrathiacalix[4]arene amido crown derivatives that can be
conveniently characterised by NMR spectroscopic methods.
The study also suggests that cyclisation process can choose an
appropriate isomer from the stereoisomeric mixture to give the
C
H
51
66
N
2
O
6
: C, 76.27; H, 8.28; N, 3.49. Found: C, 76.55; H, 8.35;
N, 3.36%. UV (λmax, MeOH): 280 nm.
,3-Distal-5,11,17,23-tetrahydro-25,27-(5-methyl-3,8-dioxo-1,10-
dioxa-4,7-diazadecano)calix[4]arene Calix[4]arene(isopropylene
1
amido) crown (3b): White solid, yield: 72%, m.p. > 340 °C (decom-
−1
1
posed). IR (KBr, υmax/ cm ): 3577, 3351, 1688. H NMR (300 MHz,
CDCl , δ in ppm): 8.31–8.15 (m, 4H, NH and OH), 7.21–7.15 (m, 6H,
3
ArH), 7.00 (d, 2H, J = 7.2 Hz, ArH), 6.92 (d, 2H, J = 7.5 Hz, ArH),
6.76–6.70 (m, 2H, ArH), 4.71 (t, 2H, J = 14.1 Hz), 4.54 (d, 1H,
J = 14.1 Hz), 4.47 (d, 1H, J = 14.1 Hz), 4.29 (t, 2H, J = 13.5 Hz), 4.05
(
3
(
d, 2H, J = 14.1 Hz), 3.64 (d, 1H, J = 5.7 Hz), 3.59 (d, 1H, J = 5.7 Hz),
.48 (s, 2H), 3.45 (d, 2H, J = 14.1 Hz), 3.27 (d, 1H, J = 13.5 Hz), 1.34
d, 3H, J = 6.9 Hz, CH ). DEPT-135 NMR (75 MHz, CDCl , δ in
3
3
ppm): 130.5, 129.7, 129.5, 129.4, 127.4, 121.0, 120.9 (ArCH), 74.8
(
OCH ), 45.0 (NHCH), 43.6 (NHCH ), 32.3 (ArCH Ar), 17.8 (CH ).
2
2
2
3
+
FAB MS m/z: 579 (M +1, 100%). Anal. Calcd for C H N O : C,
35
34
2
6
72.65; H, 5.92; N, 4.84. Found: C, 72.98; H, 5.76; N, 4.89%.

3
78 JOURNAL OF CHEMICAL RESEARCH 2010
1
,3-Distal-5,11,17,23-tetra-tert-butyl-25,27-(5-methyl-3,8-dioxo-
India for financial assistance. We also thank Sophisticated
Analytical Instrumentation Facility, Central Drug Research
Institute, Lucknow for the mass spectra reported in this paper.
Figures S1–S5 are available in the Electronic Supplemen-
tary Information and may be downloaded through www.
ingentaconnect.com/content/stl/jcr
1
,10-dioxa-4,7-diazadecano)-2,8,14,20-tetrathiacalix[4]arene (3c):
White solid, separated by column chromatography using hexane:ethyl
acetate (5:5) as the eluent, yield: 44%, m.p. > 230 °C (decomposed).
IR (KBr, υmax/ cm ): 3373, 1695. H NMR(300 MHz, CDCl , δ in
ppm): 8.83 (s, 1H, –OH), 8.71 (s, 1H, –OH), 8.34 (d, 1H, J = 8.4 Hz,
CONHCH), 8.00 (d, 1H, J = 8.4 Hz, –CONHCH ), 7.66 (s, 2H, ArH),
−1
1
3
–
2
7
.61 (s, 2H, ArH), 7.50 (s, 4H, ArH), 4.82 (t, 2H, J = 13.2 Hz,
ArOCH ), 4.57 (broad s, 1H, –CONHCH(CH )CH NHCO ), 4.51 (d,
Received 1 April 2010; accepted 27 May 2010
Paper 1000038 doi: 10.3184/030823410X12779951975025
Published online: 28 July 2010
2
3
2
1
H, J = 13.2 Hz, ArOCH ), 4.35 (d, 1H, J = 13.2 Hz, ArOCH ), 4.20
2
2
(
d, 1H, J = 6.9 Hz, CONHCH(CH )CH NHCO), 3.26 (broad d, 1H,
3 2
J = 12.9 Hz, CONHCH(CH )CH NHCO), 1.26 (broad t, 3H, J = 7.2
3
2
Hz, –CH ), 1.18 (s, 18H, –C(CH ) ), 1.11 (s, 18H, –C(CH ) ). DEPT-
3
3
3
3 3
References
1
35 (75 MHz, CDCl , δ in ppm): 138.0, 137.7, 137.6, 136.2, 135.8
3
1
J.M. Lehn and J.K. Sanders, Supramolecular chemistry: concepts and
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(
3
aromatic CH), 76.1 (ArOCH ), 45.2 (NHCH), 43.6 (NHCH ), 31.76,
2
2
+
1.42 (–C(CH ) ), 17.25 (–CH ).FAB MS m/z: 875 (M +1, 100%).
3
3
3
2
3
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47
58
2
6 4
C, 64.81; H, 6.73; N, 3.25%.
,3-Distal-5,11,17,23-tetrahydro-25,27-(5-methyl-3,8-dioxo-1,10-
1
4
5
6
7
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2
007, 9, 119.
−1
1
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(
KBr, υmax/ cm ): 3378, 1685. H NMR (300 MHz, CDCl , δ in ppm):
3
8
–
.71 (s, 1H, -OH), 8.49 (s, 1H, -OH), 8.18 (d, 1H, J = 8.4 Hz,
CONHCH), 7.80 (d, 1H, J = 8.4 Hz, –CONHCH ), 7.65 (d, 2H,
2
ArHmeta), 7.56 (d, 2H, ArHmeta), 7.53 (d, 2H, ArHmeta), 7.46 (d, 2H,
ArHmeta), 6.92 (t, 2H, J = ArHpara), 7.53 (t, 2H, J = ArHpara), 4.83 (t, 2H,
J = 13.2 Hz,ArOCH ), 4.60 (broad d, 2H, –CONHCH(CH )CH NHCO
8
9
S. Banthia and A. Samanta, Org. Biomol. Chem., 2005, 3, 1428.
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2
3
2
1
0
and ArOCH ), 4.42 (d, 1H, J = 13.2 Hz, ArOCH ), 4.17 (d, 1H, J = 6.9
2
2
Hz, CONHCH(CH )CH NHCO), 3.23 (broad d, 1H, J = 12.9 Hz,
3
2
1
1
1
2
CONHCH(CH )CH NHCO), 1.26 (broad t, 3H, J = 7.2 Hz, –CH ),
3
2
3
1
4
38.0, 137.7, 137.6, 136.2, 135.8 (aromatic CH), 76.1 (ArOCH2),
5.2 (NHCH), 43.6 (NHCH ), 31.76, 31.42 (–C(CH ) ), 17.25 (–CH ).
2
3
3
3
13 W. Verboom, P.J. Bodewes, G. Vanessen, P. Timmerman, G.J. Vanhummel,
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+
FAB MS m/z: 651 (M +1, 100%). Anal. Calcd for C H N O : C,
31
26
2
6
5
7.21; H, 4.03; N, 4.30. Found: C, 57.53; H, 3.94; N, 4.18%.
,3-Distal-5,11,17,23-tetra-tert-butyl-25,27-(cyclohexan-1,2-diyl
diamino[bis(2-oxoethoxy)]})calix[4]arene (4a): White solid, yield:
1
1
5
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408, 181.
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Struct., 2001, 563, 301.
{
5
1
−
1
7%, m.p. > 200 °C (decomposed). IR (KBr, υ / cm ): 3412, 3351,
max
1
6
1
682. H NMR (300 MHz, CDCl , δ in ppm): 8.70 (broad t, 1H,
3
CONH), 8.51 (s, 1H, OH), 8.10 (broad t, 1H, CONH), 7.80 (s, 1H,
OH), 7.13 (s, 2H, ArH), 7.04 (s, 2H, ArH), 7.00 (s, 2H, ArH), 6.98 (s,
1
1
7
8
2
H, ArH), 4.67–3.23 (m, 14H, ArCH Ar, OCH and CH), 2.07–1.49
2
2
(
1
broad m, 8H, CH -cyclohexyl), 1.24 (s, 18H, –C(CH ) ), 1.15 (s,
19 P.M. Marcos, J.R. Ascenso, M.A.P. Segurado and J.L.C. Pereira,
2
3 3
+
Tetrahedron, 2001, 57, 6977.
C. Jaime, J. Demendoza, P. Prados, P.M. Nieto and C. Sanchez, J. Org.
Chem., 1991, 56, 3372.
H.M. Chawla, S.P. Singh and S. Upreti, Tetrahedron, 2006, 62, 2901.
H.M. Chawla, S.P. Singh, S.N. Sahu and S. Upreti, Tetrahedron, 2006, 62,
8H, –C(CH ) ). FAB MS m/z: 843(M +1, 100%). Anal. Calcd for
3 3
2
0
C H N O : C, 76.92; H, 8.37; N, 3.32. Found: C, 77.14; H, 8.40;
54
70
2
6
N, 3.34%.
,3-Distal-5,11,17,23-tetrahydro-25,27-(cyclohexan-1,2-diyl
diamino[bis(2-oxoethoxy)]})calix[4]arene (4b): White solid, yield:
2
2
1
2
1
{
6
1
7
854.
−
1
4%, m.p. > 200 °C (decomposed). IR (KBr, υ / cm ): 3423, 3344,
23 A. Chakrabarti, H.M. Chawla, N. Pant, S.P. Singh and S. Upreti, 2006, 62,
8974.
24 H.M. Chawla, S.P. Singh and S. Upreti, Tetrahedron, 2007, 63, 5636.
max
1
680. H NMR (300 MHz, CDCl , δ in ppm): 8.68 (broad t, 1H,
3
CONH), 8.50 (s, 1H, OH), 8.07 (broad t, 1H, CONH), 7.80
s, 1H, OH), 7.07–6.97 (m, 7H, ArH), 6.86 (d, 2H, J = 7.2 Hz, ArH),
.67 (t,1H, J = 6.9 Hz, ArH), 6.58 (t, 2H, J = 6.9 Hz, ArH), 4.67–3.23
m, 14H, ArCH Ar, OCH and CH), 2.07–1.49 (broad m, 8H, CH -
2
2
2
5
6
7
S.P. Singh, A. Chakrabarti, H.M. Chawla and N. Pant, 2008, 64, 1983.
C.D. Gutsche and M. Iqbal, Org. Synth., 1990, 68, 234.
T. Sone,Y. Ohba, K. Moriya, H. Kumada and K. Ito, Tetrahedron, 1997, 53,
(
6
(
2
2
2
1
0689.
cyclohexyl). DEPT-135 (300 MHz, CDCl , δ in ppm): 129.7, 129.4,
3
2
8
C.D. Gutsche, M. Iqbal and D. Stewart, J. Org. Chem., 1986, 51, 742.
1
28.8, 128.6, 126.6, 121.45, 119.6 (ArCH), 74.8 (OCH ), 50.0
2
29 Y. Higuchi, M. Narita, T. Niimi, N. Ogawa, F. Hamada, H. Kumagai, N. Iki,
S. Miyano and C. Kabuto, Tetrahedron, 2000, 56, 4659.
30 B.S. Creaven, M. Deasy, J.F. Gallagher, J. McGinley and B.A. Murray,
Tetrahedron, 2001, 57, 8883.
(
(
NHCH), 31.6, 31.3 (ArCH Ar), 28.2, 22.1 (CH ). FAB MS m/z: 619
2 2
+
M +1, 100%). Anal. Calcd for C H N O : C, 73.77; H, 6.19; N,
38 38 2 6
4
.53. Found: C, 73.56; H, 6.26; N, 4.58%.
3
1
W. Verboom, A. Durie, R.J.M. Egberink, Z. Asfari and D.N. Reinhoudt,
J. Org. Chem., 1992, 57, 1313.
P. Lhotak, M. Dudic, I. Stibor, H. Petrickova, J. Sykora and J. Hodacova,
Chem. Commun., 2001, 731.
We thank the C.S.I.R for a Senior Research Fellowship (to
SPS) and Associateship (to SK) and DST and DBT, Govt. of
3
2

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