Thiourea-linked upper rim calix[4]arene neoglycoconjugates: synthesis, conformations and binding properties.

Article abstract of DOI:10.1039/b301595e

The thiourea group has been exploited to link two or four carbohydrate units at the upper rim of tetrapropoxycalix[4]arene derivatives in the cone conformation. Two synthetic methodologies were used, the first one consisting of the condensation of di- and tetraminocalix[4]arenes with the isothiocyanate of monosaccharides in dry CH2Cl2 at room temperature and the second one exploiting the condensation of an aminolactoside with a calixarene isothiocyanate. The first method allows the glycoconjugates to be obtained in 75-80% overall yields. The disfunctionalized derivatives exist in a closed flattened cone conformation in CDCl3 and CD3OD due to the formation of intramolecular hydrogen bonds involving the thiourea groups which are broken in DMSO-d6 to give an open flattened cone conformation. The thiourea groups act not only as linkers but also as binding units for anionic substrates as evidenced by solution 1H NMR and ESI-MS experiments. Turbidimetric analysis indicates that the tetraglucoside and tetragalactoside clusters give specific interactions with Concanavalin A (Con A) and peanut lectin (PNA), respectively. Both features show that the neoglycoconjugates could also be used as site specific molecular delivery systems.

Full text of DOI:10.1039/b301595e

View Article Online / Journal Homepage / Table of Contents for this issue
Thiourea-linked upper rim calix[4]arene neoglycoconjugates:
synthesis, conformations and binding properties†
Francesco Sansone,* Elisa Chierici, Alessandro Casnati and Rocco Ungaro*
Dipartimento di Chimica Organica e Industriale, Università degli Studi,
Parco Area delle Scienze 17/A, I-43100 Parma, Italy. E-mail: rocco.ungaro@unipr.it;
Fax: ϩ39.0521.905472; Tel: ϩ39.0521.905555
Received 12th February 2003, Accepted 26th March 2003
First published as an Advance Article on the web 8th April 2003
The thiourea group has been exploited to link two or four carbohydrate units at the upper rim of tetrapropoxycalix[4]-
arene derivatives in the cone conformation. Two synthetic methodologies were used, the first one consisting of the
condensation of di- and tetraminocalix[4]arenes with the isothiocyanate of monosaccharides in dry CH Cl at room
2
2
temperature and the second one exploiting the condensation of an aminolactoside with a calixarene isothiocyanate.
The first method allows the glycoconjugates to be obtained in 75–80% overall yields. The difunctionalised derivatives
exist in a closed flattened cone conformation in CDCl and CD OD due to the formation of intramolecular hydrogen
3
3
bonds involving the thiourea groups which are broken in DMSO-d to give an open flattened cone conformation.
6
The thiourea groups act not only as linkers but also as binding units for anionic substrates as evidenced by solution
1
H NMR and ESI-MS experiments. Turbidimetric analysis indicates that the tetraglucoside and tetragalactoside
clusters give specific interactions with Concanavalin A (Con A) and peanut lectin (PNA), respectively. Both features
show that the neoglycoconjugates could also be used as site specific molecular delivery systems.
1
2
Introduction
through the method proposed by Lindhorst and co-workers,
13
melting the corresponding glycosyl bromides with KSCN.
In the case of the galactosyl derivative we found that a
more reproducible procedure, which gives the β-galactosyl iso-
thiocyanate 4 in 50% yield (β/α = 8/1), is to heat the bromide
dissolved in acetone with KSCN at 110 ЊC for 3 h in a sealed
tube.
As glycosyl acceptors we selected the conformationally
locked cone di- and tetraminocalix[4]arenes 1 and 2. They are
both known compounds, but we modified the procedures for
In the last few years, we have been engaged in the synthesis of
hybrid macrocyclic receptors characterised by the presence of
polar binding groups in close proximity to a hydrophobic
cavity, which are attractive for studying the selective recognition
of bio-relevant species.
In this context our attention was primarily devoted to calix-
1
1
b,2
3
arene conjugates with amino acids
and carbohydrates. The
main motivation for the synthesis of macrocycle-based glyco-
14
4
conjugates is the possibility they offer of studying the so-called
their synthesis in order to improve the yield and the isolation of
the products in pure form. To this end, we treated the corre-
sponding nitro derivatives with hydrazine in presence of Pd/C
5
cluster glycoside effect, which is responsible for the tight
binding of sugars to proteins via multivalency. Moreover,
calixarene-based glycoconjugates are also attractive as a novel
type of amphiphilic carbohydrates able to self-assemble and
give interesting supramolecular aggregates.
Several synthetic procedures to link sugar moieties to phen-
olic oxygen atoms of calix[4]arenes (lower rim) are known,
but only a few are reported for the upper rim (aromatic
6
15
(
10%) at 70 ЊC or, alternatively, with Pd/C in hydrogen atmos-
phere (2 bar), achieving in both cases the desired amino
7
16
derivatives in 95% yield, after very easy work-up procedures.
The condensation reactions between the di- and tetra-
minocalix[4]arenes 1 and 2 and the glycosyl isothiocyanates 3
and 4 were performed in dry CH Cl at room temperature for
4 h. The compounds 5–8 were isolated after flash chromato-
graphy in 75–80% yield and quantitatively deprotected to the
3a,8
3b,9
2
2
nuclei) which use the formation of ether
or carbon–carbon
2
9c,10
bonds.
We envisaged the possibility of synthesising new
upper rim glycocalix[4]arenes exploiting the formation of thio-
ureas, a method which has been successfully used to obtain
corresponding derivatives 9–12 with the Zemplen method
(
CH ONa, CH OH).
1
1
3 3
cyclodextrin-scaffolded glycoclusters. In addition, the thio-
urea groups could be used as binding units for anionic species
thus conferring host–guest properties to the glycoclusters and
making them attractive as novel site specific molecular delivery
systems.
We tried to extend this procedure to the synthesis of lactose
containing derivatives, but we were not able to prepare the
corresponding lactosyl isothiocyanate, either by melting or by
solution methods. For this reason, we investigated an altern-
17
ative possibility via the β-lactosyl azide which was reduced to
the amino derivative 13. This was then reacted with the diiso-
1
4b
thiocyanate calix[4]arene 14
to give the bislactosyl com-
Results and discussion
pound 15, subsequently deprotected to 16 (Scheme 2). However,
the yield of this reversed condensation procedure was signifi-
cantly lower than the previous ones and therefore we decided
not to apply it to the known tetraisothiocyanate calix[4]arene
derivative. All new compounds were fully characterised by
NMR, MS and elemental analysis.
Synthesis
The synthesis of calix[4]arene glycoconjugates 9–12 is outlined
in Scheme 1.
We decided, for our purposes, to use as glycosyl donors the
isothiocyanates 3 and 4 in the β-form which were synthesised
14b
The difunctionalised glycocalixarenes 9 and 10 are soluble in
acetone, methanol and DMSO, while the tetraglucoside deriv-
1
†
Electronic supplementary information (ESI) available: H NMR
Ϫ5
ative 11 is soluble in pure water up to 5 × 10 M concentration
1
spectra in different solvents of compounds 5–12, 15 and 16, dynamic H
NMR experiments on compounds 5 and 9 and NOESY 2D spectra
of compounds 5 and 12. See http://www.rsc.org/suppdata/ob/b3/
b301595e/
Ϫ4
which increases to 1 × 10 M in 80/20 H O/DMSO. The tetra-
2
galactoside receptor 12 is less soluble in water compared with
Ϫ5
11 (1.2 × 10 M).
1
802
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3

View Article Online
Scheme 1 Reagents and conditions: i, CH Cl , r.t., 24 h; ii, NaOCH , CH OH, r.t., 30 min.
2
2
3
3
Scheme 2 Reagents and conditions: i, DMF, 100 ЊC, 24 h; ii, NaOCH , CH OH, r.t., 30 min.
3
3
and the rate of interconversion between them depend on
solvent, steric bulkiness and hydrogen bonding ability of the
Conformational properties
2e,19
1
It is well known that cone tetraalkylated calix[4]arenes are not
rigid molecules but they experience a residual mobility between
two flattened cone (also called pinched cone) conformations,
which are usually fast exchanging on the NMR time scale at
substituents at the upper rim.
The H NMR spectrum of
compound 5 in CDCl (see ESI†) shows, at room temperature,
3
two doublets at δ = 7.10 and 7.07 and a triplet at δ = 6.91 which
account for the six protons of the unsubstituted aromatic rings.
The two signals (one broad) belonging to the functionalised
18
room temperature. The populations of the two conformers
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9
1803

View Article Online
1
13
aromatic rings appear at a quite high field (δ = 6.08 and 6.03).
The H and C NMR spectra of the tetrafunctionalised
In DMSO-d (see ESI†) the relative positions of the two sets
receptors 7, 8, 11 and 12 show the expected C symmetry and no
6
4
of aromatic protons are inverted, the signals belonging to the
substituted rings moving downfield (δ = 7.03 and 7.01) and
those relative to the unsubstituted rings moving upfield (6.48–
particular conformational feature connected with the calix[4]-
arene ring mobility in all solvents tested (CDCl , CD OD and
3
3
DMSO-d ).
6
20
1
6
.32 ppm). Similar data were also obtained with compound 6.
As observed with most thioureido sugars, the H NMR
spectra of all glycocalix[4]arenes synthesised in this work show
some broad signals, in particular the NHs, the aromatic and the
anomeric protons, even in solvents of high donicity such as
2e,19
This behaviour is indicative
of a conformational change
(
Fig. 1) from a closed flattened cone conformation, stable in
CDCl because of intramolecular hydrogen bonding between
3
the two upper rim substituents, to the more classical open
DMSO-d . This broadening must be mainly attributed to the
6
flattened cone conformation, evidenced in DMSO-d6.
restricted rotation of the pseudo-amide NH–C᎐S bonds of the
thiourea units and the consequent equilibrium among different
rotamers (Fig. 2), excluding the E,E rotamer because of the two
bulky substituents. The relatively low-field chemical shifts of
the H1 anomeric proton (δ = 5.90–5.20) observed for these
compounds suggest the parallel disposition of the C–H1 bond
20
with respect to the C᎐S bond and, as a consequence, the anti
᎐
disposition of the sulfur atom and H . NOESY experiments
B
performed in DMSO-d6 at 300 K with the tetragalactosyl-
thioureido derivative 12 (see ESI†) evidenced the presence of
an intense cross peak between H-2 of the glycoside unit and the
closest NH proton (H ), which, thus, is in anti position with
B
respect to H1. The much more intense cross peak between the
two different NH protons (H and H ) indicates, together with
A
B
the other spectral data, Z,Z (Fig. 2) as the predominant con-
formation of the thiourea units at room temperature. On the
other hand, a weaker but significant cross peak between H2 and
H can be explained by the presence in solution of a lower per-
A
centage of a Z,E conformation (Z,E in Fig. 2). Moreover, a
1
very weak correlation between H and H-1 is consistent with a
A
second Z,E rotamer (Z,E in Fig. 2), while the correlation
2
between H and the aromatic protons in ortho positions to the
B
thiourea suggests the presence of the E,Z rotamer (Fig. 2).
In the case of the disubstituted, protected compound 5
similar results are observed, even if the Z,Z rotamer seems to be
largely the most abundant in solution on the basis of the cross
peak intensities. Similar data were also collected for all other
glycocalixarenes 6–11.
1
Dynamic H NMR studies in CDCl , CD OD and DMSO-d
3
3
6
with both the protected and the deprotected glycosyl derivatives
show a progressive sharpening of the signals by heating. Upon
cooling (273–213 K) in CDCl and CD OD, the signals split
Fig. 1 The two flattened cone conformations of the difunctionalised
glycosylthioureido calix[4]arenes.
3
3
into more complicated patterns because of the progressive
freezing of the different rotamers of the thiourea units. The
1
Surprisingly, the H NMR spectra in CD OD of compounds
3
5
(see ESI†) and 6 are similar to those observed in CDCl , thus
observed coalescence temperatures in CDCl for the thioureido
NH protons of the glycocalix[4]arenes 5–8 and 15(290–280 K)
3
3
indicating the closed conformation is more stable even in a
polar, protic solvent such as methanol. Since a very similar sol-
vent dependent conformational behaviour is also observed with
the O-deprotected derivatives 9 and 10, which have several
additional OH groups potentially able to form hydrogen bonds,
we conclude that the H-bonding interactions which stabilise
the closed conformation are those involving the thiourea
groups and, possibly, only the glycoside endocyclic oxygen
atoms, which are know to interact with hydrogen bonding
are in agreement with literature data on sugar thiourea deriv-
21
atives. As expected, in the explored temperature range (350–
213 K), no interconversion is evidenced from a flattened cone
conformer to the other, showing that the observed dynamic
phenomenon is only related to the thiourea isomerism.
No evidence for the formation of self-assembled dimeric
capsules of compounds 7 and 8, which are known to be easily
22
formed with upper rim tetraurea calix[4]arene derivatives, was
20a,d
1
donor groups.
obtained by MALDI-TOF mass spectra, H NMR dilution
Fig. 2 Possible rotamers of the glycosylthioureido groups in the calixarene derivatives.
1
804
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9

View Article Online
1
5c
Ϫ1
experiments and CD spectra
in apolar solvents. With the
Table 1 Association constants (Kass/M ) for receptor 9 determined in
1
DMSO-d by H NMR titration experiments (300 MHz, 300 K)
same type of experiments, the presence of dimeric species of the
6
bisglycosylated compounds 5, 6 and 9, 10, which could be also
in agreement with the observed H NMR data, was also ruled
a
Kass b
Substrate
1
out in both CDCl and CD OD.
3
3
Ϫ
H PO
90
31
17
58
36
103
170
2
4
Ϫ
Cl
CH COO
N-Acetyl--alaninate
β--Glucose-6-phosphate
Benzoate
Ϫ
3
Binding properties
Multivalent glycosylated ligands can simultaneously interact
with several equivalent binding sites of macromolecular recep-
23
Benzylphosphonate
tors, such as lectins and antibodies. Tailored ligands having a
number of exposed carbohydrate units corresponding to that of
the receptor recognition sites can sometime form 1 : 1 com-
a
b
As tetrabutylammonium salts. Errors within 10%.
24
plexes with it, although, more generally, the synthetic glyco-
glycocalixarenes 9–12. For the tetrafunctionalised receptors 11
and 12 the addition of the tetrabutylammonium salts of several
anions in DMSO-d causes a large broadening of the signals
clusters give cross-linking interactions among different receptor
25
molecules, causing their agglutination. An easy method to
detect this ligand-mediated aggregation of proteins is turbidi-
6
relative to the thiourea N–H protons, which did not allow the
evaluation of the association constants. However, in the case of
the bisglucosyl derivative 9 consistent downfield shifts of the
N–H protons were observed upon titration with several anionic
species in the same solvent. Moreover, a downfield shift of the
signals of the unsubstituted aromatic rings and a more evident
upfield shift of those relative to the substituted ones suggest a
conformational rearrangement of the receptor to bring both
the thiourea units close to the anionic substrates. Job plots
and non-linear least squares analysis of the titration data gave
a 1 : 1 stoichiometry for the complexes and allowed the
determination of the association constants reported in Table 1.
The values of Kass are low because of the competition of a
solvent with high donicity such as DMSO. Considering that
25
metric analysis, which allows microprecipitation in a solution
of the protein after addition of the cluster to be checked, fol-
lowing the absorbance increase. In this way, we evaluated the
ability of the tetraglycosylated derivatives 11 and 12 to interact
with Concanavalin A (Con A), a selective α--glucoside and
α--mannoside binding lectin, and with peanut lectin (PNA,
Arachis hypogaea), that specifically binds β--galactosides and
26
N-acetyl--galactosamine. The addition of glycocalixarene 11
to a solution of Con A caused a rapid increase of the absorb-
ance values which were registered over a period of 4.5 h (Fig. 3),
until they were stable. The observation for 4.5 h of a reference
suspension of the calixarene derivative showed that no absorb-
ance changes occur in the absence of Con A, as for a Con A
solution in the absence of 11. At that point, a 400-fold molar
amount of -glucose was added and a decrease of turbidity
took place, although it was not sufficient to reduce the absorb-
ance to the starting value. The same amount of -galactose did
not cause any change in the absorbance values of the Con A/11
mixture evidencing the specific involvement of the glucose
units of 11 in the interaction with this lectin. Moreover, a solu-
tion of PNA did not become turbid with compound 11 and no
turbidity change was observed by adding the galactose contain-
ing calixarene 12 to the Con A solution. On the other hand,
the galactocalix[4]arene 12 was able to agglutinate PNA lectin
and this process was also partially inhibited by adding an
excess of -galactose, as expected on the basis of the known
carbohydrate selectivity properties of this lectin.
28
29
going from DMSO to an apolar solvent such as CDCl one has
3
to expect an increase of the association constants of at least one
30
order of magnitude, the data reported in Table 1 reveal a
trend which deserves some comments. The evidenced selectivity
order benzyl phosphonate > benzoate > dihydrogen phosphate
N-acetyl--alaninate > β--glucose-6-phosphate > chloride >
acetate indicates that, beside the primary interaction of the
anionic centre with the thiourea N–H groups, which seems to
be stronger with the phosphate containing guests, other factors
affect binding. The presence of the aromatic ring in the
guest improves the binding, probably because of favourable
>
31
interactions with the sugar backbone (Fig. 4).
Fig. 3 Turbidimetric analysis (25 ЊC, λ = 350 nm): absorbance increase
for a mixture of 11 and Concanavalin A (-᭿-); absorbance decrease
after addition of -glucose (-∆-); absorbance of 11 (-ᮀ-) used as
reference.
Fig. 4 Proposed mode of binding of benzylphosphonate to 9.
A second attractive feature of the glycoconjugates syn-
thesised is the presence of a hydrophobic cavity in close proxim-
ity to the thiourea groups, a circumstance which could confer
host properties to our compounds. This would be interesting
since selected guests could be transported by the glycocluster
toward specific organs which recognise the exposed sugar units.
Since the thiourea groups are known to interact with anionic
The preference of the glycoconjugates 9 and 11 for the
binding of phosphate containing guests was also confirmed by
competitive ESI-MS experiments with mixtures of different
anions in methanol. An equivalent of each anionic species
(as tetrabutylammonium salts) was allowed to equilibrate with
one equivalent of host in methanol solution before registering
the mass spectra (Fig. 5). In both cases the molecular peak of
27
guests we investigated the anion recognition properties of the
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9
1805

View Article Online
Ϫ1
g . Elemental analyses were performed using a Termoquest
112 CHNSO instrument and are reported as percentages. TLC
1
was performed on silica gel Merck 60 F254, and flash chromato-
graphy using 32–63, 60 Å ICN silica gel. 5,17-Dinitro-25,26,27,
1
5a,b
2
2
8-tetra-n-propoxycalix[4]arene,
6,27,28-tetra-n-propoxycalix[4]arene
5,11,17,23-tetranitro-25,
15
and 5,17-diisothio-
14b
cyanate-25,26,27,28-tetra-n-propoxycalix[4]arene
were pre-
pared according to literature procedures.
NMR Titration experiments
Titration experiments were performed in DMSO-d by titrating
6
Ϫ3
Ϫ2
a 5 × 10 M solution of the receptor with a 4.4 × 10
solution of the guest, varying the host/guest ratio from 2 : 1 to
: 9.
M
1
Tetrabutylammonium salts
Ϫ
Ϫ
All tetrabutylammonium salts, excluding H PO4 and Cl , were
2
prepared by adding 1 equiv. of a freshly titrated solution of
tetrabutylammonium hydroxide in methanol to a solution of
the corresponding acid in methanol. The mixture was stirred at
room temperature for 2 h and evaporated to dryness under
reduced pressure. The resulting deliquescent solid or syrup was
dried at high vacuum for 24 h, checked by NMR and stored in a
desiccator.
Fig. 5 Top: ESI-MS spectrum of a mixture containing receptor 11 and
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Cl , Br , I , HSO and H PO . Bottom: ESI-MS spectrum of a
4
2
4
Ϫ
Ϫ
Ϫ
mixture containing receptor 9 and Cl , Br , H PO , glucose-6-
2
4
phosphate (G6P), acetate, acetyl--alaninate.
ESI-MS complexation studies
Ϫ3
Ϫ
4
1
0 µl of 5 × 10 M solutions of the receptor and guests
Ϫ5
the 1 : 1 host : guest complex with H PO is the most intense in
2
were mixed and diluted to 7 × 10 M. The mixtures were
analysed in negative ionisation mode by direct perfusion in ESI-
MS interface; injection flow-rate = 20 µl min ; desolvation
temperature = 150 ЊC; source block temperature = 80 ЊC; cone
and desolvation gas flow-rates = 1.6 and 8 l min , respectively;
capillary = 3.0 KV; cone = 30 V; extractor = 3 V. Spectra were
the spectra. Furthermore, since the molecular peak of the free
ligand is almost undetectable in the case of the tetrafunctional-
ised receptor 11, while it is the base peak in the experiment with
the difunctionalised derivative 9, we conclude that the anion
binding ability of the former is significantly higher.
Ϫ1
Ϫ1
registered with a scan time of 6 s.
Conclusions
Thiourea linked upper rim calix[4]arene glycoconjugates with
exposed two or four glucose, galactose and lactose units
have been synthesised for the first time. Dynamic H NMR
Turbidimetric analysis
Ϫ1
1
500 µl of a glycocalix[4]arene dispersion (0.3 mg ml ) were
quickly mixed with 500 µl of a lectin solution (0.5 mg ml ).
Ϫ1
experiments in solvents of different polarity and NOESY two-
dimensional spectra allowed the disclosure of the conform-
ational features of the neoglycoconjugates at the level of both
the thiourea bonds and the calix[4]arene skeleton. Turbidi-
metric experiments show that the tetraglucosyl and tetragalac-
tosyl derivatives specifically bind to Concanavalin A (Con A)
and peanut lectin (PNA, Arachis hypogaea), respectively,
through multivalent interactions which are, for the first time,
evidenced for upper rim calix[4]arene glycoclusters. The binding
The turbidity of the solution was monitored by reading the
absorbance at 350 nm at regular time intervals until no notice-
able changes could be observed, using a Perkin Elmer UV-Vis
Lambda BIO 20 spectrophotometer. The sample cell was
thermostated by a Peltier device at 25 ЊC. All experiments
were performed in triplicate.
General procedures for the synthesis of the amino calixarene
derivatives 1 and 2
1
studies performed by H NMR and electrospray mass spectro-
metry (ESI-MS) show both di- and tetrafunctionalised macro-
cyclic hosts 9–12 are able to preferentially complex anionic
guests having an aromatic tail. These feature make the new
glycoclusters attractive as possible site specific molecular
delivery systems.
Procedure A: to a solution in ethanol of the appropriate nitro
derivative, hydrazine hydrate (20 equiv. for each nitro group)
and a catalytic amount of Pd/C (10%) were added. The
reaction mixture was refluxed for 5 h and quenched by catalyst
filtration. The filtrate was evaporated at reduced pressure, the
residue dissolved with ethyl acetate and washed with distilled
water. The organic layer was separated, dried over MgSO4
Experimental
and evaporated to dryness at reduced pressure to obtain the
pure amino calix[4]arene. Procedure B: a solution in ethyl
acetate of the appropriate nitro derivative containing Pd/C
All moisture sensitive reactions were carried out under nitrogen
atmosphere. All dry solvents were prepared according to stand-
ard procedures and stored over molecular sieves. Melting points
were determined in capillaries sealed under nitrogen on an
(
10%) was stirred under H (2 bar) at room temperature for
2
2
4 h. The catalyst was filtered off and the filtrate was evapor-
1
Electrothermal apparatus and are uncorrected. H (300 and
ated to dryness to give the amino calixarene without further
purification.
1
3
4
00 MHz) and C (75 MHz) NMR spectra were recorded on
Bruker AC300 and AMX400 spectrophotometers (partially
deuterated solvents were used as internal standards). Coupling
constant (J) values are given in Hz. Mass spectra were recorded
in ESI mode on a Micromass ZMD. Optical rotations were
measured at 20 ЊC on a Perkin Elmer 241 Polarimeter, using
5
,17-Diamino-25,26,27,28-tetrapropoxycalix[4]arene 1
The compound was obtained in 95% yield through both pro-
cedures A and B and showed the same spectroscopic properties
Ϫ1
2
14a
the wavelength at 589 nm; [α] values are given in 10 deg cm
as previously reported.
D
1
806
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9

View Article Online
5
,11,17,23-Tetraamino-25,26,27,28-tetrapropoxycalix[4]arene 2
br d, NH), 7.08 (4 H, m, Ar), 6.34 (6 H, m, Ar), 5.87 (2 H, br t,
H-1), 5.36 (2 H, dd, J 9.6 and 3.3, H-3), 5.35–5.25 (2 H, m,
H-4), 5.07 (2 H, t, J 9.6, H-2), 4.33 (4 H, d, J 12.9, Hax of
The compound was obtained in 95% yield through both pro-
cedures A and B and showed the same spectroscopic properties
as previously reported.
ArCH Ar), 4.31–4.21 (2 H, m, H-5), 4.02 (4 H, d, J 5.9, H-6a
14b,15c
2
and H-6b), 3.92 (4 H, t, J 7.9, OCH ), 3.67 (4 H, t, J 6.8,
2
OCH ), 3.16 (4 H, d, J 12.9, H of ArCH Ar), 2.11, 2.05, 1.99,
2
eq
2
2
,3,4,6-Tetraacetyl-ꢀ-galactosyl isothiocyanate 4
To a solution of 2,3,4,6-tetraacetyl-β-galactosyl bromide
1.00 g, 2.43 mmol) in acetone (50 ml), KSCN (2.35 g,
4.3 mmol) was added. The mixture was heated at 110 ЊC in a
1
.93, (3 H each, 4 s, CH CO), 1.89–1.80 (8 H, m, OCH CH ),
3
2
2
13
1.05 (6 H, t, J 7.4, CH
), 0.92 (6 H, t, J 7.3, CH ); δ (75 MHz,
3
3 C
(
2
DMSO-d
133.0, 127.5, 124.2, 121.9, 116.8 (Ar), 81.7 (C-1), 76.6, 76.2
(OCH ), 71.3 (C-5), 70.7 (C-3), 68.3 (C-2), 67.6 (C-4), 61. 2
(C-6), 30.6, 30.2 (ArCH Ar), 22.9, 22.6 (OCH CH ), 20.6, 20.4
(CH CO), 10.5, 9.9 (CH ); m/z (ESI) 1423.3 (100, [M ϩ Na] ).
) 181.5 (CS), 169.9, 169.3 (CO), 155.1, 154.4, 135.8,
6
sealed tube for 3 h, then the reaction was quenched by evapor-
ation of the solvent at reduced pressure. The residue was solved
in CH Cl (30 ml), washed with distilled water (2 × 20 ml) and
2
2
2
2
ϩ
2
2
3
3
evaporated to dryness at reduced pressure. The crude residue
was purified by flash column chromatography to obtain 4 as
a white solid (475 mg, 50%). The product showed the same
5,11,17,23-Tetrakis[(2,3,4,6-tetra-O-acetyl-ꢀ-D-glucopyrano-
syl)thioureido]-25,26,27,28-tetrapropoxycalix[4]arene 7
12
spectroscopic properties as previously reported.
Eluent for flash column chromatography: Et O/MeOH 25/1;
2
white solid; yield 80%; mp 175–178 ЊC; (Found: C 54.27, H
General procedure for the preparation of the protected glycosyl-
thioureido calix[4]arenes 5–8
5
5
1
.66, N 5.11. Calc. for C100H128N O S : C 54.34, H 5.84, N
8 40 4
Ϫ1
.07%); [α]D Ϫ6.1 (c 0.5, CHCl ); νmax/cm (KBr) 3373, 1754,
3
222; δ (400 MHz, CDCl ) 7.98 (4 H, br s, NH), 6.82 (4 H, br s,
A solution of the aminocalix[4]arene and the appropriate iso-
H
3
12
NH), 6.52 (8 H, br s, Ar), 5.82 (4 H, t, J 9.2, H-1), 5.34 (4 H, dd,
J 9.5 and 9.3, H-3), 5.04 (4 H, dd, J 9.3 and 9.2, H-2), 4.93 (4 H,
thiocyanate 3 or 4 (2 equiv. for each NH group) in dry
2
CH Cl (2.5 ml per 0.1 mmol of calixarene) was stirred for 24 h
2
2
dd, J 9.7 and 9.5, H-4), 4.46 (4 H, d, J 13.7, Hax of ArCH Ar),
at room temperature. The reaction was diluted with CH Cl and
2
2
2
4
3
.38 (4 H, dd, J 12.5 and 4.2, H-6a), 4.17–4.01 (8 H, m, H-6b),
.90–3.80 (12 H, m, OCH and H-5), 3.22 (4 H, d, J 13.7, H of
quenched by addition of distilled water. The organic layer was
separated, washed with distilled water and evaporated to dry-
ness at reduced pressure. The pure products were isolated by
flash column chromatography.
2
eq
ArCH Ar), 2.15–1.91 (56 H, m, CH CO and OCH CH ), 1.03
2
3
2
2
(
12 H, t, J 7.3, CH ); δ (75 MHz, CDCl ) 181.8 (CS), 171.5,
3 C 3
1
8
70.6, 169.7, 169.5 (CO), 155.6, 136.4, 129.8, 124.9, 124.3 (Ar),
3.0 (C-1), 76.5 (OCH ), 73.7 (C-5), 72.7 (C-3), 70.8 (C-2), 68.2
2
5
2
,17-Bis[(2,3,4,6-tetra-O-acetyl-ꢀ-D-glucopyranosyl)thioureido]-
5,26,27,28-tetrapropoxycalix[4]arene 5
(
C-4), 61.6 (C-6), 30.8 (ArCH Ar), 23.1 (OCH CH ), 20.9,
2 2 2
2
0.7, 20.5, 20.4 (CH CO), 10.1 (CH ); m/z (ESI) 1105.7 (100,
3 3
ϩ
Eluent for flash column chromatography: AcOEt/hexane 1/1;
white solid; yield 75%; mp 164–167 ЊC; (Found: C 59.85, H
[M ϩ 2H] ).
6
4
1
.21, N 4.02. Calc for C H N O S : C 59.99, H 6.33, N
5,11,17,23-Tetrakis[(2,3,4,6-tetra-O-acetyl-ꢀ-D-galactopyrano-
syl)thioureido]-25,26,27,28-tetrapropoxycalix[4]arene 8
70
88
4
22 2
Ϫ1
.00%); [α] Ϫ31.5 (c 0.5, CHCl ); νmax/cm (KBr) 3369, 1755,
D
3
222; δ (300 MHz, DMSO-d ) 9.70 (2 H, br s, NH), 7.80 (2 H,
H
6
Eluent for flash column chromatography: CH Cl /MeOH 50/1;
2
2
br d, NH), 7.03 (2 H, d, J 2.0, Ar), 7.01 (2 H, d, J 2.0, Ar), 6.48–
white solid; yield 75%; mp 180–182 ЊC; (Found: C 54.19, H
6
5
.32 (6 H, m, Ar), 5.89 (2 H, br t, H-1), 5.36 (2 H, t, J 9.5, H-3),
.01 (2 H, t, J 9.5, H-2), 4.96 (2 H, t, J 9.5, H-4), 4.34 (4 H, d,
5
5
1
.71, N 5.13. Calc. for C100H128N O S : C 54.34, H 5.84, N
8
40 4
Ϫ1
.07%); [α] ϩ35.8 (c 0.5, DMSO); νmax/cm (KBr) 3371, 1752,
D
J 12.9, Hax of ArCH Ar), 4.19 (2 H, dd, J 11.2 and 4.6, H-6a),
2
224; δ (300 MHz, CDCl ) 7.99 (4 H, br s, NH), 6.80 (4 H, br s,
H
3
4
.05–3.91 (4 H, m, H-5 and H-6b), 3.88 (4 H, t, J 7.9, OCH ),
2
NH), 6.60 (4 H, br s, Ar), 6.52 (4 H, br s, Ar), 5.83 (4 H, br t,
H-1), 5.45 (4 H, d, J 3.0, H-4), 5.20 (4 H, dd, J 9.6 and 3.0, H-3),
3
.67 (4 H, t, J 6.8, OCH ), 3.16 (4 H, d, J 12.9, H of
2
eq
ArCH Ar), 2.09, 2.02, 1.99, 1.95, (3 H each, 4 s, CH CO), 2.08–
2
3
5
4
.14 (4 H, t, J 9.6, H-2), 4.48 (4 H, d, J 13.6, Hax of ArCH Ar),
.20–4.01 (12 H, m, H-5, H-6a and H-6b), 3.96–3.83 (8 H, m,
2
1
.81 (8 H, m, OCH CH ), 1.04 (6 H, t, J 7.3, CH ), 0.93 (6 H, t,
2
2
3
J 7.4, CH ); δ (400 MHz, CDCl ) 7.45 (2 H, br s, NH), 7.10 (2
3
H
3
OCH ), 3.22 (4 H, d, J 13.6, H of ArCH Ar), 2.17–1.83 (56 H,
2
eq
2
H, d, J 6.8, Ar), 7.07 (2 H, d, J 6.2, Ar), 6.91 (2 H, t, J 6.8, Ar),
.59 (2 H, br s, NH), 6.08, 6.03 (2 H each, br s, Ar), 5.85 (2 H, t,
J 9.6, H-1), 5.32 (2 H, t, J 9.6, H-3), 5.08 (2 H, t, J 9.6, H-2),
m, CH CO and OCH CH ), 0.98 (12 H, t, J 7.7, CH ); δ (75
3
2
2
3
C
6
MHz, CDCl ) 181.8 (CS), 171.3, 171.5, 170.0, 169.6 (CO), 156.0
3
(
(
(
Ar ipso), 83.4 (C-1), 76.5 (OCH ), 72.7 (C-5), 70.9 (C-3), 68.4
2
4
.99 (2 H, t, J 9.6, H-4), 4.45 (4 H, d, J 13.2, Hax of ArCH Ar),
2
C-2), 67.3 (C-4), 61.0 (C-6), 30.8 (ArCH Ar), 23.2
2
4
.41–4.36 (2 H, m, H-6a), 4.12 (2 H, d, J 12.5, H-6b), 3.99 (4 H,
OCH CH ), 20.9, 20.7, 20.6, 20.4 (CH CO), 10.1 (CH );
2
2
3
3
t, J 7.9, OCH ), 3.88–3.80 (2 H, m, H-5), 3.74 (4 H, t, J 7.9,
OCH ), 3.19 (4 H, d, J 13.2, H of ArCH Ar), 2.11, 2.10, 2.02,
2
2ϩ
ϩ
m/z (ESI) 1127.7 (100, [M ϩ 2Na] ), 2231.4 (30, [M ϩ Na] ).
2
eq
2
2
1
.01, (3 H each, 4 s, CH CO), 1.98–1.85 (8 H, m, OCH CH ),
3
2
2
General procedure for the deprotection from acetyl groups
.10 (6 H, t, J 7.4, CH ), 0.93 (6 H, t, J 7.5, CH ); δ (75 MHz,
3
3
C
DMSO-d ) 181.2 (CS), 169.8, 169.3, 169.2 (CO), 155.0, 154.0,
The [(2,3,4,6-tetra-O-acetyl-β--glycopyranosyl)thioureido]-
25,26,27,28-tetrapropoxycalix[4]arenes were dissolved in
MeOH and the solution was adjusted to pH 8–9 by addition of
freshly prepared methanolic NaOMe. The solution was stirred
at room temperature for 1 h and then neutralised with Amber-
6
1
7
35.4, 133.0, 131.9, 127.5, 123.8, 121.8 (Ar), 81.3 (C-1), 76.4,
6.1 (OCH ), 72.6 (C-5), 71.9 (C-3), 70.4 (C-2), 67.8 (C-4), 61.6
2
(
C-6), 30.5, 30.0 (ArCH Ar), 22.8, 22.5 (OCH CH ), 20.4, 20.3,
2
2
2
2
0.2, 20.1 (CH CO), 10.3, 9.7 (CH ); m/z (ESI) 1423.3 (100,
3 3
ϩ
ϩ
[M ϩ Na] ).
lite IR-120 (H ) ion exchange resin. The resin was removed by
filtration and after evaporation of the solvent the unprotected
compounds 9–12 were obtained as white solids.
5
,17-Bis[(2,3,4,6-tetra-O-acetyl-ꢀ-D-galactopyranosyl)-
thioureido]-25,26,27,28-tetrapropoxycalix[4]arene 6
5
,17-Bis(ꢀ-D-glucopyranosylthioureido)-25,26,27,28-tetra-
Eluent for flash column chromatography: AcOEt/hexane 1/1;
white solid; yield 80%; mp 154–156 ЊC; (Found: C 59.87, H
propoxycalix[4]arene 9
6
4
1
.23, N 4.05. Calc. for C H N O S : C 59.99, H 6.33, N
Yield 82%; decomposition without melting at 168 ЊC; (Found:
70
88
4
22 2
Ϫ1
.00%); [α] Ϫ3.83 (c 0.5, CHCl ); νmax/cm (KBr) 3415, 1754,
C 60.76, H 6.65, N 5.20. Calc. for C H N O S : C 60.88,
D
3
54 72
4
14 2
Ϫ1
217; δ (300 MHz, DMSO-d ) 9.68 (2 H, br s, NH), 7.91 (2 H,
H 6.81, N 5.26%); [α]D Ϫ4.2 (c 0.5, EtOH); νmax/cm (KBr)
H
6
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9
1807

View Article Online
3
415, 1218; δ (300 MHz, CD OD) 6.99 (4 H, d, J 7.1, Ar), 6.81
under H (2 bar) for 2 h. The reaction mixture was filtered and
H
3
2
(
2 H, t, J 7.1, Ar), 6.42 (2 H, s, Ar), 6.34 (2 H, s, Ar), 5.43 (2 H,
evaporated to give 13 as a white solid (330 mg, 75%); mp 95–97
d, J 8.8, H-1), 4.48 (4 H, d, J 13.3, Hax of ArCH Ar), 4.01 (4 H,
ЊC; (found: C 49.02, H 5.95, N 2.37. Calc. for C H NO : C
2
26 37
17
t, J 7.7, OCH ), 3.84 (2 H, dd, J 11.8 and 2.4, H-6a), 3.76 (4 H,
49.13, H 5.87, N 2.20%); [α]D ϩ4.4 (c 0.5, CHCl ); δ (300
3 H
2
t, J 7.2, OCH ), 3.66 (2 H, dd, J 11.8 and 4.9, H-6b), 3.42 (2 H,
MHz, CDCl ) 5.30 (1 H, dd, J 3.4 and 0.6, H-4Ј), 5.18 (1 H, dd,
2
3
t, J 8.8, H-3), 3.38–3.25 (6 H, m, H-2, H-4 and H-5), 3.17 (4 H,
d, J 13.3, Heq of ArCH Ar), 2.02–1.88 (4 H, m, OCH CH ),
J 9.4 and 9.3, H-3), 5.05 (1 H, dd, J 10.4 and 7.6, H-2Ј), 4.91
(1 H, dd, J 10.4 and 3.4, H-3Ј), 4.68 (1 H, dd, J 9.4 and 8.6,
H-2), 4.44 (1 H, d, J 8.6, H-1), 4.41 (1 H, dd, J 12.0 and 1.8,
H-6a), 4.13–3.98 (3 H, m, H-6b, H-6Јa and H-6Јb), 4.05 (1 H, d,
J 7.6, H-1Ј) 3.83 (1 H, td, J 6.3 and 1.0, H-5Ј), 3.69 (1 H, dd,
J 9.9 and 9.3, H-4), 3.55 (1 H, ddd, J 9.9, 5.1 and 1.8, H-5),
2
2
2
1
.11 (6 H, t, J 7.4, CH ), 0.94 (6 H, t, J 7.4, CH ); δ (75 MHz,
3
3
C
CD OD) δ 183.2 (CS), 158.6, 155.1, 137.4, 137.2, 136.1, 130.1,
3
1
30.0, 124.5, 123.7 (Ar), 85.6 (C-1), 79.5, 79.0 (OCH ), 78.2
2
(
C-5), 77.9 (C-3), 74.0 (C-2), 71.6 (C-4), 62.8 (C-6), 32.0, 31.9
(
1
ArCH Ar), 24.6, 24.2 (OCH CH ), 11.2, 10.4 (CH ); m/z (ESI)
087.3 (100, [M ϩ Na] ).
2.15, 2.12, 2.06, 2.05, 2.04, 1.96 (3 H each, 6 s, CH CO);
2
2
2
3
3
ϩ
δC (75 MHz, CDCl ) 170.4, 170.1, 170.0, 169.6, 169.0 (CO),
3
1
01.2 (C-1Ј), 84.6 (C-1), 73.7, 73.0,72.5, 71.0 (C-4, C-5, C-3,
5
,17-Bis(ꢀ-D-galactopyranosylthioureido)-25,26,27,28-tetra-
C-3Ј, C-2), 70.7 (C-5Ј), 69.1 (C-2Ј), 66.6 (C-4Ј), 62.3 (C-6), 60.8
propoxycalix[4]arene 10
(C-6Ј), 20.8, 20.6, 20.4 (CH CO).
3
Yield 85%; mp 182–183 ЊC; (Found: C 60.74, H 6.73, N 5.18.
Calc. for C H N O S : C 60.88, H 6.81, N 5.26%); [α] ϩ2.45
5
,17-Bis[(2,3,6-tri-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-ꢀ-D-
galactopyranosyl)-1-ꢀ-D-glucopyranosyl)thioureido]-
5,26,27,28-tetrapropoxycalix[4]arene 15
54
72
4
14
2
D
Ϫ1
(
c 0.5, EtOH); νmax/cm (KBr) 3414, 1217; δH (300 MHz,
2
CD OD) 6.97 (4 H, d, J 7.4, Ar), 6.80 (2 H, t, J 7.4, Ar), 6.50
3
(
2 H, s, Ar), 6.32 (2 H, s, Ar), 5.39 (2 H, br s, H-1), 4.47 (4 H, d,
To a solution of 5,17-bisisothiocyanate-25,26,27,28-tetraprop-
14b
J 13.3, Hax of ArCH Ar), 4.00 (4 H, t, J 7.7, OCH ), 3.88 (2 H,
d, J 2.6, H-4), 3.76 (4 H, t, J 6.9, OCH ), 3.71–3.49 (10 H, m,
H-2, H-3, H-5, H-6a and H-6b), 3.18, 3.16 (2 H each, 2 d,
J 13.3, Heq of ArCH Ar), 2.03–1.91 (4 H, m, OCH CH ), 1.12
oxycalix[4]arene 14 (140 mg, 0.20 mmol) in dry DMF (10
ml) 2,3,6-tri-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β--galacto-
pyranosyl)-1-β--glucopyranosylamine 13 (277 mg, 0.44 mmol)
was added. The reaction mixture was stirred for 24 h at 100 ЊC.
After cooling to room temperature the reaction was quenched
with 1 M HCl (20 ml). After extraction with CH Cl (3 × 25
2
2
2
2
2
2
(
6 H, t, J 7.4, CH ), 0.94 (6 H, t, J 7.5, CH ); δ (75 MHz,
3
3
C
CD OD) 183.1 (CS), 158.5, 155.1, 137.2, 137.0, 136.2, 133.1,
3
2
2
1
30.0, 124.5, 123.7 (Ar), 86.1 (C-1), 78.3, 78.2 (OCH ), 77.9
ml), the combined organic layers were washed with distilled
water and evaporated to dryness at reduced pressure. The
residue was purified by flash column chromatography (AcOEt/
toluene 3/2) to afford 14 as a white solid (180 mg, 46%); mp
2
(
C-5), 75.8 (C-3), 71.4 (C-2), 70.5 (C-4), 62.5 (C-6), 32.0, 31.9
(
ArCH Ar), 24.6, 24.2 (OCH CH ), 11.2, 10.4 (CH ); m/z (ESI)
2
2
2
3
ϩ
1
087.3 (100, [M ϩ Na] ).
1
65–167 ЊC; (found: C 56.89, H 5.94, N 2.91. Calc. for
5
,11,17,23-Tetrakis(ꢀ-D-glucopyranosylthioureido)-25,26,27,28-
C H N O S : C 57.03, H 6.12, N 2.83%); [α] Ϫ31.5 (c 0.5,
94
120
4
38
2
D
Ϫ1
tetrapropoxycalix[4]arene 11
CHCl ); νmax/cm (KBr) 3385, 1753, 1220; δH (400 MHz,
3
DMSO-d ) 9.66 (2 H, br s, NH), 7.78 (2 H, br d, NH), 7.05–7.02
6
Yield 89%; decomposition without melting at 225 ЊC; (Found:
(
5
4 H, m, Ar), 6.40–6.29 (6 H, m, Ar), 5.79 (2 H, br t, H-1), 5.28–
.10 (6 H, m, H-2Ј,H-3 and H-4Ј), 4.94–4.81 (4 H, m, H-2 and
C 52.96, H 6.13, N 7.30. Calc. for C H N O S : C 53.11, H
6
8
96
8
24 4
Ϫ1
6
3
.13, N 7.27%); [α]D ϩ28.0 (c 0.5, DMSO); νmax/cm (KBr)
H-3Ј), 4.87 (2 H, d, J 8.1, H-1Ј), 4.40–4.20 (6 H, m, H-4, H-6a
419, 1221; δH (300 MHz, CD OD) 6.86, 6.77 (4 H each, 2 bs,
3
and H-6b), 4.28 (4H, d, J 13.4, Hax of ArCH Ar), 4.07–3.98
2
Ar), 5.47 (4 H, br s, H-1), 4.50 (4 H, d, J 13.2, Hax of ArCH Ar),
2
(
8 H, m, H-5, H-5Ј, H-6Јa and H-6Јb), 3.91 (4 H, t, J 7.6,
3
5
.92–3.83 (10 H, m, H-6b and OCH ), 3.69 (4 H, dd, J 11.8 and
.0, H-6a), 3.49–3.29 (16 H, m, H-2, H-3, H-4 and H-5), 3.22
2
OCH ), 3.68 (4 H, t, J 6.6, OCH ), 3.15 (4 H, d, J 13.4, H of
2
2
eq
ArCH Ar), 2.11–1.85 (50 H, m, OCH CH and CH CO), 1.04
2
2
2
3
(
4 H, d, J 13.2, Heq of ArCH Ar), 2.04–1.94 (8 H, m, OCH -
2
2
(
6 H, t, J 7.3, CH ), 0.92 (6 H, t, J 7.4, CH ); δ (75 MHz,
3
3
C
CH ), 1.06 (12 H, t, J 7.3, CH ); δ (75 MHz, CDCl ) 183.4
2
3
C
3
DMSO-d ) 170.7–169.2 (CO), 157.1, 154.4, 128.6, 124.1, 123.7,
6
(
(
(
(
CS), 171.5, 156.2, 137.1, 133.7, 126.0 (Ar), 85.9 (C-1), 79.7
1
22.0 (Ar), 100.3 (C-1Ј), 82.2 (C-1), 77.0, 76.6 (OCH ), 76.3
2
OCH ), 79.3 (C-5), 78.5 (C-3), 74.5 (C-2), 71.7 (C-4), 63.0
2
(
C-4), 75.6 (C-5), 74.0 (C-3), 72.5 (C-3Ј), 70.8 (C-2), 70.4 (C-5Ј),
C-6), 32.3 (ArCH Ar), 24.7 (OCH CH ), 11.1 (CH ); m/z
2
2
2
3
6
8.8 (C-2Ј), 66.6 (C-4Ј), 61.9 (C-6), 60.8 (C-6Ј), 30.6 (ArCH2-
2Ϫ
Ϫ
ESI) 767.5 (100, [M Ϫ 2H] ), 1535.7 (22, [M Ϫ H] ).
Ar), 23.1, 22.6 (OCH CH ), 20.5, 20.4, 20.2, 20.0 (CH CO),
2
2
3
3ϩ
1
[
0.3, 9.5 (CH ); m/z (ESI) 659.1 (100, [M ϩ H] ), 1011.3 (90,
3
2ϩ ϩ
5
2
,11,17,23-Tetrakis(ꢀ-D-galactopyranosylthioureido)-
5,26,27,28-tetrapropoxycalix[4]arene 12
M ϩ 2Na] ), 1999.6 (80, [M ϩ Na] ).
Yield 90%; decomposition without melting at 184 ЊC; (Found:
5,17-Bis[(ꢀ-D-galactopyranosyl)-1-ꢀ-D-glucopyranosyl)-
thioureido]-25,26,27,28-tetrapropoxycalix[4]arene 16
C 52.92, H 6.20, N 7.29. Calc. for C H N O S : C 53.11, H
6
8
96
8
24 4
Ϫ1
6
3
.13, N 7.27%); [α]D ϩ35.8 (c 0.5, DMSO); νmax/cm (KBr)
The deprotection of 15 (180 mg, 0.09 mmol) to 16 was carried
out using the general procedure previously described for the
other glycocalixarenes; white solid (107 mg, 85%); mp 196–198
ЊC; (found: C 56.90, H 6.73, N 3.91. Calc. for C H N O S :
425, 1545; δH (300 MHz, CD OD) 6.85, 6.75 (4 H each, 2 bs,
3
Ar), 5.51 (4 H, br s, H-1), 4.51 (4 H, d, J 13.2, Hax of ArCH Ar),
2
3
.98–3.59 (34 H, m, H-2, H-3, H-4, H-5, H-6a, H-6b and
66
92
4
24 2
OCH ), 3.21 (4 H, d, J 13.2, H of ArCH Ar), 2.04–1.91 (8 H,
2
eq
2
C 57.04, H 6.67, N 4.03%); [α]D ϩ12.25 (c 0.4, DMSO);
m, OCH CH ), 1.06 (12 H, t, J 7.4, CH ); δ (75 MHz, CD OD)
2
2
3
C
3
Ϫ1
νmax/cm (KBr) 3420, 122; δ (300 MHz, CD OD) 7.01 (4 H, d,
H
3
1
83.2 (CS), 156.0, 137.5, 136.8, 133.8, 133.2, 125.6 (Ar), 86.4
J 7.4, Ar), 6.82 (2 H, t, J 7.4, Ar), 6.35 (4 H, br s, Ar), 5.45 (2 H,
(
(
(
C-1), 78.6 (OCH , C-5), 76.1 (C-3), 72.1 (C-2), 70.6 (C-4), 62.9
2
d, J 8.98, H-1), 4.47 (4 H, d, J 13.2, Hax of ArCH Ar), 4.38
2
C-6), 32.3 (ArCH Ar), 24.7 (OCH CH ), 11.0 (CH ); m/z
2
2
2
3
(
2 H, d, J 7.4, H-1Ј), 4.01 (4 H, t, J 7.3, OCH ), 3.87–3.70 (20 H,
Ϫ
2
ESI) 1535.4 (100, [M] ).
m, H-2, H-3, H-4, H-2Ј, H-3Ј and H-4Ј), 3.62–3.44 (12 H, m,
H-5, H-5Ј, H-6a, H-6b, H-6Јa and H-6Јb), 3.18 (4 H, d, J 13.1,
Heq of ArCH Ar), 2.02–1.87 (8 H, m, OCH CH ), 1.11 (6 H, t,
2
,3,6-Tri-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-ꢀ-D-galacto-
2
2
2
pyranosyl)-1-ꢀ-D-glucopyranosylamine 13
J 7.3, CH ), 0.94 (6 H, t, J 7.1, CH ); δ (75 MHz, CD OD)
3
3
C
3
A suspension of 2,3,6-tri-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-
β--galactopyranosyl)-1-β--glucopyranosylazide (450 mg,
182.5 (CS), 155.6, 155.0, 137.4, 137.2, 136.1, 130.2, 130.1,
124.5, 123.8 (Ar), 105.2 (C-1Ј), 85.4 (C-1), 80.7 (C-4), 78.3,
17
0
.69 mmol) and Pd/C (10%) in CH CN (30 ml) was stirred
78.0, 77.9, 77.4, 77.1 (OCH , C-5, C-3, C-3Ј), 74.8 (C-2), 73.6
3
2
1
808
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9

View Article Online
(
(
1
C-5Ј), 72.5 (C-2Ј), 70.3 (C-4Ј), 62.5 (C-6), 62.0 (C-6Ј), 32.0
ArCH Ar), 24.6, 24.2 (OCH CH ), 11.2, 10.4 (CH ); m/z (ESI)
411.4 (100, [M ϩ Na] ), 717.1 (65, [M ϩ 2Na] ).
14 (a) P. Timmerman, H. Boerrigter, W. Verboom and D. N.
Reinhoudt, Recl. Trav. Chim. Pays-Bas, 1995, 114, 103–111;
(b) A. M. van Wageningen, E. Snip, W. Verboom, D. N. Reinhoudt
and H. Boerrigter, Liebigs Ann./Recueil, 1997, 2235–2245.
2
2
2
3
ϩ
2ϩ
1
1
5 (a) E. Kelderman, L. Derhaeg, G. J. T. Heesink, W. Verboom, J. F. J.
Engbersen, N. F. Van Hulst, A. Persoons and D. N. Reinhoudt,
Angew. Chem., Int. Ed. Engl., 1992, 31, 1075–1077; (b) W. Verboom,
A. Durie, R. J. M. Egberink, Z. Asfari and D. N. Reinhoudt, J. Org.
Chem., 1992, 57, 1313–1316; (c) A. M. Rincón, P. Prados and
J. de Mendoza, J. Am. Chem. Soc., 2001, 123, 3493–3498.
Acknowledgments
This work was partially supported by M.I.U.R. (COFIN 2002,
Calixarene Glycoconjugates” Project) and EU (TMR grant
“
FMRX-CT98-0231). The authors thank Prof. T. K. Lindhorst
and Prof. S. Penadés for helpful discussions on the synthesis of
glycosyl thiocyanate and on glycosyl thioureido derivatives,
respectively. The Centro Interdipartimentale Misure of Parma
University is also gratefully acknowledged for NMR facilities.
6 When we had established these procedures, another similar synthetic
protocol to obtain amino derivatives of calix[4]arene was
1
5c
reported.
17 F. D. Tropper, F. O. Andersson, S. Braun and R. Roy, Synthesis,
992, 618–620.
1
1
8 (a) A. Yamada, T. Murase, K. Kikukawa, T. Matsuda and
S. Shinkai, Chem. Lett., 1990, 455–458; (b) T. Harada, J. M.
Rudzinski, E. Osawa and S. Shinkai, Tetrahedron, 1993, 49, 5941–
References
5
954; (c) A. Yamada, T. Murase, K. Kikukawa, T. Arimura
1
(a) F. Sansone, M. Segura and R. Ungaro, in Calixarenes 2001,
ed. Z. Asfari, V. Böhmer, J. Harrowfield and J. Vicens, Kluwer
Academic Publishers, Dordrecht, 2001, p. 496; (b) F. Sansone,
L. Baldini, A. Casnati, M. Lazzarotto, F. Ugozzoli and R. Ungaro,
Proc. Natl. Acad. Sci. USA, 2002, 99, 4842–4847; (c) A. Casnati,
F. Sansone and R. Ungaro, Acc. Chem. Res., 2003, 36(4), in press.
(a) A. Casnati, M. Fabbi, N. Pelizzi, A. Pochini, F. Sansone,
R. Ungaro, E. Di Modugno and G. Tarzia, Bioorg. Med. Chem.
Lett., 1996, 6, 2699–2704; (b) F. Sansone, S. Barboso, A. Casnati,
M. Fabbi, A. Pochini, F. Ugozzoli and R. Ungaro, Eur. J. Org.
Chem., 1998, 897–905; (c) F. Sansone, S. Barboso, A. Casnati,
D. Sciotto and R. Ungaro, Tetrahedron Lett., 1999, 40, 4741–4744;
and S. Shinkai, J. Chem. Soc., Perkin Trans. 2, 1991, 793–797;
(d ) A. Arduini, M. Fabbi, L. Mirone, A. Pochini, A. Secchi and
R. Ungaro, J. Org. Chem., 1995, 69, 1454–1457.
19 (a) J. Scheerder, R. H. Vreekamp, J. F. J. Engbersen, W. Verboom,
J. P. M. van Duynhoven and D. N. Reinhoudt, J. Org. Chem., 1996,
61, 3476–3481; (b) N. Pelizzi, A. Casnati and R. Ungaro, Chem.
Commun., 1998, 2607–2608.
20 (a) J. M. García Fernández, J. L. Jiménez Blanco, C. Ortiz Mellet
and J. Fuentes, J. Chem. Soc., Chem. Commun., 1995, 57–58; (b) J. L.
Jiménez Blanco, J. M. Benito, C. Ortiz Mellet and J. M. García
Fernández, Org. Lett., 1999, 1, 1217–1220; (c) V. M. Díaz Pérez,
C. Ortiz Mellet, J. Fuentes and J. M. García Fernández, Carbohydr.
Res., 2000, 326, 161–175; (d ) J. M. García Fernández and C. Ortiz
Mellet, Adv. Carbohydr. Chem. Biochem., 2000, 55, 35–135.
21 J. M. Benito, M. Gómez-García, J. L. Jiménez Blanco, C. Ortiz
Mellet and J. M. García Fernández, J. Org. Chem., 2001, 66, 1366–
1372.
22 D. M. Rudkevich, in Calixarenes 2001, ed. Z. Asfari, V. Böhmer,
J. Harrowfield and J. Vicens, Kluwer Academic Publishers,
Dordrecht, 2001, p. 155.
23 (a) T. K. Lindhorst, Top. Curr. Chem., 2002, 218, 201–235;
(b) B. T. Houseman and M. Mrksich, Chem. Biol., 2002, 9, 443–454.
24 (a) P. I. Kitov, J. M. Sadowska, G. Mulvey, G. D. Armstrong,
H. Ling, N. S. Pannu, R. J. Read and D. R. Bundle, Nature, 2000,
403, 669–6672; (b) Z. Zhang, E. A. Merritt, M. Ahn, C. Roach,
Z. Hou, C. L. M. J. Verlinde, W. G. J. Hol and E. Fan, J. Am. Chem.
Soc., 2002, 124, 12991–12998.
25 (a) K. Aoi, K. Itoh and M. Okada, Macromolecules, 1995, 28, 5391–
5393; (b) D. Zanini and R. Roy, J. Am. Chem. Soc., 1997, 119, 2088–
2095; (c) T. Fujimoto, C. Shimizu, O. Hayashida and Y. Aoyama,
J. Am. Chem. Soc., 1998, 120, 601–602; (d ) R. Roy, D. Pagé,
F. Figueroa Perez and V. Verez Bencomo, Glycoconjugate J., 1998,
15, 251–263; (e) H. Kitano, Y. Sumi and K. Tagawa, Bioconjugate
Chem., 2001, 12, 56–61.
26 (a) R. Lotan, E. Skutelsky, D. Danon and N. Sharon, J. Biol. Chem.,
1975, 250, 8518–8523; (b) T. J. Williams, N. R. Plessas, I. J. Goldstein
and J. Lönngren, Arch. Biochem. Biophys., 1979, 195, 145–151.
27 (a) P. D. Beer and P. A. Gale, Angew. Chem., Int. Ed., 2001, 40, 487–
516; (b) A. Casnati, F. Sansone and R. Ungaro, Adv. Supramol.
Chem., 2003, 9, 165–218.
2
(
d ) L. Frish, F. Sansone, A. Casnati, R. Ungaro and Y. Cohen,
J. Org. Chem., 2000, 65, 5026–5030; (e) M. Lazzarotto, F. Sansone,
L. Baldini, A. Casnati, P. Cozzini and R. Ungaro, Eur. J. Org.
Chem., 2001, 595–602.
3
(a) A. Marra, M.-C. Scherrmann, A. Dondoni, A. Casnati,
P. Minari and R. Ungaro, Angew. Chem., Int. Ed. Engl., 1994, 33,
2
479–2481; (b) A. Dondoni, A. Marra, M.-C. Scherrmann,
A. Casnati, F. Sansone and R. Ungaro, Chem. Eur. J., 1997, 3, 1774–
782.
D. A. Fulton and J. F. Stoddart, Bioconjugate Chem., 2001, 12,
55–672.
(a) Y. C. Lee and R. T. Lee, Acc. Chem. Res., 1995, 28, 321–327;
b) J. J. Lundquist and E. Toone, Chem. Rev., 2002, 102, 555–578.
1
4
5
6
7
8
6
(
M. Mammen, S.-K. Choi and G. M. Whitesides, Angew. Chem., Int.
Ed., 1998, 37, 2754–2794.
L. Guangtao, M.-F. Gouzy and J.-H. Fuhrhop, Top. Curr. Chem.,
2
002, 218, 133–158.
(a) S. J. Meunier and R. Roy, Tetrahedron Lett., 1996, 37, 5469–5472;
b) R. Roy and J. M. Kim, Angew. Chem., Int. Ed., 1999, 38, 369–
72; (c) C. Saitz-Barria, A. Torres-Pinedo and F. Santoyo-González,
(
3
Synlett, 1999, 12, 1891–1894; (d ) J. Budka, M. Tkadlecová,
P. Lhoták and I. Stibor, Tetrahedron, 2000, 56, 1883–1887;
(
e) A. Dondoni, X. Hu, A. Marra and H. D. Banks, Tetrahedron
Lett., 2001, 42, 3295–3298.
9
(a) A. Marra, A. Dondoni and F. Sansone, J. Org. Chem, 1996, 61,
5
155–5158; (b) C. Félix, H. Parrot-Lopez, V. Kalchenko and A. W.
Coleman, Tetrahedron Lett., 1998, 39, 9171–9174; (c) A. Dondoni,
M. Kleban, X. Hu, A. Marra and H. D. Banks, J. Org. Chem., 2002,
6
7, 4722–4733.
0 A. Dondoni, M. Kleban and A. Marra, Tetrahedron Lett., 1997, 38,
801–7804.
28 H.-J. Schneider and A. Yatsimirsky, in Principles and Methods in
Supramolecular Chemistry, John Wiley & Sons, Chichester, 2000,
p. 151.
1
1
7
1 (a) C. Ortiz Mellet, J. M. Benito, J. M. García Fernández, H. Law,
K. Chmurski, J. Defaye, M. L. O’Sullivan and H. Caro, Chem. Eur.
J., 1998, 4, 2523–2531; (b) J. J. García-Lopez, F. Santoyo-González,
A. Vargas-Berenguel and J. J. Giménez-Martínez, Chem. Eur. J.,
29 C. S. Wilcox, in Frontiers in Supramolecular Chemistry and
Photochemistry, ed. H.-J. Schneider and H. Dürr, VCH, Weinheim,
1991, p. 123.
30 T. R. Kelly and M. H. Kim, J. Am. Chem. Soc., 1994, 116, 7072–
1
999, 5, 1775–1784; (c) R. Roy, F. Hernández-Mateo and
7080.
F. Santoyo-González, J. Org. Chem., 2000, 65, 8743–8746.
2 T. K. Lindhorst and C. Kieburg, Synthesis, 1995, 1228–1230.
3 K. P. Ravindranathan and H. J. Jennings, J. Carbohydr. Chem., 1990,
31 (a) J. Jiménez-Barbero, E. Junquera, M. Martín-Pastor, S. Sharma,
C. Vicent and S. Penadés, J. Am. Chem. Soc., 1995, 117, 11198–
11204; (b) J. C. Morales and S. Penadés, Angew. Chem., Int. Ed.,
1998, 37, 654–657.
1
1
9
, 778–781.
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 8 0 2 – 1 8 0 9
1809