Synthesis of deeper calix-sugar-based on the Sonogashira reaction

Article abstract of DOI:10.1055/s-2001-18076

The effective synthesis of tetrakis(mannopyranosyl) calix[4]arenes based in the cross-coupling Sonogashira reaction of propargyl α-D-mannopyranosyde and 25,26,27,28-tetrakis(4′-iodobenzyloxy)calix[4]arene is described.

Full text of DOI:10.1055/s-2001-18076

LETTER
1699
Synthesis of Deeper Calix-sugar–Based on the Sonogashira Reaction
Synthesis of
D
r
eeper Calix-sugar–
n
ase
d
on the
c
Sonogashi
i
stion co Pérez-Balderas, Francisco Santoyo-González*
Instituto de Biotecnología, Departamento de Química Orgánica Facultad de Ciencias, Campus Fuentenueva s/n, Universidad de Granada,
Granada, E-18071-Spain
E-mail: fsantoyo@ugr.es
Received 1 June 2001
been performed by glycosidation7a,b,e or by formation of
Abstract: The effective synthesis of tetrakis(mannopyranosyl)
amide linkages.7g,h,j Other less used strategies include the
calix[4]arenes based in the cross-coupling Sonogashira reaction of
formation of thiourea linkages,7k the Wittig olefination re-
propargyl -D-mannopyranosyde and 25,26,27,28-tetrakis(4'-iodo-
action,7d the Suzuki reaction7i and 1,3 dipolar cycloaddi-
benzyloxy)calix[4]arene is described.
tion reactions.7l
Key words: alkynes, glycoclusters, carbohydrates, calixarenes, Pd-
Considering the great utility of the Sonogashira reaction10,
catalyzed reactions
we though that this coupling methodology could be also
an adequate tool for grafting saccharides to calixarenes al-
lowing also the simultaneous expanding of the cavity of
carbohydrate-containing clusters. Recently, the Sonog-
oshira reaction has demonstrated its applicability in the
carbohydrate field for the construction of related struc-
tures such as cyclic hydrils of 2,2’-bipyridine and ace-
tylenosaccharides,11a “sugar-rods”,11b -Gal-containing
clusters11c and acetyleno-linked adenosine dimers.11d,e
Propargyl glycosides were thought to be adequate sugar
building-blocks to perform Sonogashira coupling reaction
owing to its easy accessibility. The synthetic strategy en-
visaged was based in the preliminary incorporation of an
aryl iodide into a calixarene core by alkylation followed
by Sonogashira cross-coupling of propargyl glycosides.
Thus, calix[4]arenes 1 and 2 were reacted with commer-
cially available p-iodobenzyl bromide using classical
etherification conditions (NaH–DMF)12 giving the corre-
sponding iodoaryl derivatives 3 and 4 in high yield (97
and 84%, respectively). From these compounds, the tet-
rakis(mannopyranosyl) calix[4]arenes 6 and 7 were
obtained13 by the cross-coupling Sonogashira reaction
with 511b,14 using (PPh3)4Pd as catalyst in the presence of
a base (Et3N or piperidine). When (PPh3)2PdCl2 and a cat-
alytic amount of CuI were used in these reactions a com-
plex mixture of calixarene derivatives was formed
together with the compound resulting of the oxidative ho-
mocoupling of the propargyl sugar derivative 5.15 In order
to evaluate the biological activity of the obtained calix-
sugars, compounds 6 and 7 were fully deprotected by
standard Zemplen de-O-acetylation16 to the correspond-
ing free polyhydroxylated derivatives 8 and 9 (68 and
71% yield, respectively). The cross-linking properties of
compound 8 toward the tetrameric plant lectin Concavalin
A (Con A) were investigated by ELLA inhibition essays17
using methyl -D-mannopyranoside as a reference stan-
dard. Unfortunately, these essays showed that calix-sugar
8 has worse inhibitory properties in comparison with the
reference. Similar essays could not be performed with
compound 9 owing to its low solubility in water. The in-
clusion properties of these new calix-sugars will be the
objective of future investigations.
The development of supramolecular chemistry has led to
a growing interest in the design and synthesis of macrocy-
clic molecules containing intramolecular cavities.1 In this
regard, calix[n]arenes2 have been used as building blocks
for the synthesis of large host molecules with different su-
pramolecular functions because they are readily accessi-
ble for chemical modification on both smaller (lower) and
larger (upper) rims by attachment of a wide range of po-
tential ligating groups. In particular, the synthesis of mo-
lecular receptors based on calixarenes have attracted some
attention for their potential applications in the recognition
of biologically active compounds (sugars,3 aminoacids,4
peptides,5 nucleosides6) under physiological conditions.
Calix-sugars7 as well as calixresorcarene-sugars8 have
thus emerged as new medium-sized glycoconjugates. Re-
markable features of those compounds are their polyhy-
droxylated and chiral nature. In addition, the
incorporation of biorecognizable saccharide epitopes
made of them potential molecular vectors for site-specific
delivery of therapeutics.
As the host-guest properties of cavitands are dependent on
the dimensions of their cavities, numerous synthetic at-
tempts have been made to deepen the cavity, rigidify the
structure, and functionalize the cavitand surface for fur-
ther applications.9 Up to the present, limited efforts have
been conducted to enlarge the cavity of calix-sugar-based
cavitands.7i Continuing our efforts in the design of multi-
valent glycoforms varying in molecular weights, shapes,
valencies and geometries, we report in this paper the syn-
thesis and biological activity of new calix-sugar with a
deepened cavity constructed on the narrow rim using the
Sonogashira reaction for the assembly of the sugar moi-
eties onto the calixarene scaffolds.
As other synthetic-based calixarene receptors, calix-sug-
ars have been generally prepared using the methodologies
of classical organic synthesis. In the most of the cases, the
grafting of the saccharides to the calixarene core have
Synlett 2001, No. 11, 26 10 2001. Article Identifier:
1437-2096,E;2001,0,11,1699,1702,ftx,en;D13601ST.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0936-5214

1700
F. Pérez-Balderas, F. Santoyo-González
LETTER
Scheme
Ital. 1997, 127, 637. (j) Danil de Namor, A. F.; Cleverley, R.
M.; Zapata-Ormachea, M. L. Chem. Rev. 1998, 98, 2495.
(k) Pochini, A.; Ungaro, R. In Comprehensive
Acknowledgement
This work was financially supported by the Dirección General de
Investigación Científica y Tecnica (PB98-1320).
Supramolecular Chemistry; Vogtle, F., Ed.; Pergamon
Press: Oxford, 1996, 103. (l) Gutsche, C. D. Aldrichimica
Acta 1995, 28, 3. (m) Gutsche, C. D.; Iqbal, M. Org. Synth.,
Coll. 1993, Vol VIII, 75. (n) Gutsche, C. D.; Dhawan, B.;
Leonis, M.; Stewart, D. Org. Synth., Coll. Vol VIII, 1993,
77. (o) Munch, S. H.; Gutsche, C. D. Org. Synth., Coll. 1993,
Vol VII, 80. (p) Arduini, A.; Casnati, A. In Calixarenes in
Macrocyclic Synthesis: A Practical Approach; Parker, D.,
Ed.; Oxford University Press: Oxford, 1996, 145.
(q) Calixarenes in Action; Mandolini, L.; Ungaro, R., Eds.;
Imperial College Press: London, 2000.
References and Notes
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Synlett 2001, No. 11, 1699–1702 ISSN 0936-5214 © Thieme Stuttgart · New York

LETTER
Synthesis of Deeper Calix-sugar–Based on the Sonogashira Reaction
1701
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Physical data for compound 4: 5,11,17,23-tetra-tert-Butyl-
25,26,27,28-tetrakis(4’-iodo-benzyloxy)calix[4]arene
obtained as a solid (0.292 g, 84%): mp 212–214 ºC; IR
(KBr): 1479, 1194, 1009 cm–1; 1H NMR (300 MHz, CDCl3)
: 7.55, 6.97 (2 d, 16 H, J = 8.1 Hz, 4 C6H4 I), 6.75 (s, 8 H,
Ar), 4.75 (s, 8 H, 4 CH2O), 4.11, 2.91 (2 d, 8 H, J = 12.7 Hz,
ArCH2Ar), 1.08 (s, 36 H, 4 CMe3); 13C NMR (75 MHz,
CDCl 3) : 152.5, 145.0, 137.7, 133.6, 137.2, 131.4, 125.3,
93.6, 76.1, 33.9, 31.5, 31.4.; HRMS–FAB calcd for
C72H76I4O4 + Na: 1535.1820 (M + Na)+, found: 1535.1828.
(13) General procedure for the synthesis of calix-sugars 6 and
7: To a degassed solution of the corresponding 4-
iodophenylcalixarene (3 and 4)(0.07 mmol)and the
propargyl mannoside 5 (0.32 mmol) in anhyd piperidine
(8 mL) was added [Pd(PPh3)4] (0.007 mmol) and CuI. The
solution was heated at 75 °C under an argon atmosphere for
30 min. The piperidine was removed by evaporation under
vacuum. The residue was acetylated with Ac2O–Pyridine
(1:1, 10 mL). Conventional work-up gave a crude product,
which was purified by column chromatography (silica gel,
EtOAc–hexane 2:1) giving the calix-sugar 6 and 7,
respectively.
(8) (a) Fujimoto, T.; Shimizu, C.; Hayashida, O.; Aoyama, Y. J.
Am. Chem. Soc. 1997, 119, 6676. (b) Hayashida, O.; Kato,
M.; Akagi, K.; Aoyama, Y. J. Am. Chem. Soc. 1999, 121,
11597. (c) Hayashida, O.; Nishiyama, K.; Matsuda, Y.;
Aoyama, Y. Tetrahedron Lett. 1999, 40, 3407.
Physical data for 6: 25,26,27,28-tetrakis{4’-[1’’-O-
(2’’’,3’’’,4’’’,6’’’-tetra-O-Acetyl- -D-manno-
pyranosyl)prop-3’’-ynyl]benzyloxy}calix[4]arene
obtained as a solid (0.120 g, 74%): mp 100–103 °C; [ ]D +52
(c 0.5, CHCl3); IR (KBr): 1749, 1369, 1224, 1049 cm–1; 1H
NMR (300 MHz, CDCl3) : 7.27 (d, 8 H, J = 8.0 Hz, C 6H4),
7.15 (d, 8 H, J = 8.0 Hz, C6H4), 6.51–6.15 (m, 12 H, C6H3),
5.31 (dd, 4 H, J = 10.1 and 3.3 Hz, H-3), 5.25 (t, 4 H,
J = 10.0 Hz, H-4), 5.25 (d, 4 H, J = 3.3 Hz, H-2), 5.06 (s, 4
H, H-1), 4.85 (br s, 8 H, CH2O), 4.43 (AB system, 8 H,
(9) Rudkevich, D. M.; Rebek, J. Eur. J. Org. Chem. 1999, 1991.
(10) (a) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron
Lett. 1975, 4467. (b) Sonogashira, K. In Comprehensive
Organic Synthesis; Trost, B. M.; Fleming, I., Eds.;
Pergamon Press: New York, 1991, 521. (c) Rossi, R.;
Carpita, A.; Bellina, F. Org. Prep. Proced. Int. 1995, 27,
127. (d) Brandsma, L.; Vasilevsky, S. F.; Verkrujisse, H. D.
In Application of Transition Metal Catalyst in Organic
Synthesis; Springer: Berlin, 1998, 174. (e) Sonogashira, K.
In Metal-Catalyzed Cross.Coupling Reactions; Diederich,
F.; Stang, P. J., Eds.; Wiley: Weinheim, 1998, 203.
(11) (a) Burli, R.; Vasella, A. Helv. Chim. Acta 1999, 82, 485.
(b) Roy, R.; Das, S. K.; Santoyo-González, F.; Hernández-
Mateo, F.; Dam, T. K.; Brewer, C. F. Chem. Eur. J. 2000, 6,
1757. (c) Dam, T. K.; Roy, R.; Das, S. K.; Oscarson, S.;
Brewer, C. F. J. Biol. Chem 2000, 19, 14223. (d) Liu, B.;
Roy, R. J. Chem. Soc., Perkin Trans. 1 2001, 773.
(e) Gunji, H.; Vasella, A. Helv. Chim. Acta 2000, 83, 2975.
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332, 215.
J = 16.0 Hz,
= 10.2 Hz; ArCH2O), 4.24 (dd, 4 H,
J = 12.1 and 4.8 Hz, H-6), 4.07–3.94 (m, 12 H, H-5,6',
ArCH2Ar), 2.78 (d, 4 H, J = 13.7 Hz, ArCH2Ar), 2.08, 2.02,
1.97, 1.92 (4 s, 48 H, 16 MeCO); 13C NMR (75 MHz,
CDCl3) : 170.0, 169.9, 169.8, 155.0, 138.3, 135.3, 131.7,
129.7, 128.4, 122.5, 121.5, 96.3, 87.2, 83.6, 75.9, 69.5, 69.1,
66.1, 62.4, 55.8, 31.4, 20.9, 20.8, 20.7; HRMS–FAB calcd
for C124H128O44 + Na: 2343.767 (M + Na)+; found: 2343.765.
Physical data for 7: 5,11,17,23-tetra-tert-Butyl-
25,26,27,28-tetrakis{4’-[1’’-O-(2’’’,3’’’,4’’’,6’’’-tetra-O-
acetyl- -D-mannopyranosyl)prop-3’’-ynyl]benzyl-
oxy}calix[4]arene obtained as a solid (0.127 g, 71%): mp
127–129 °C;[ ]D +180 (c 1, chloroform); IR (KBr): 1753,
1485, 1367, 1223 cm–1; 1H NMR (300 MHz, CDCl3) : 7.32
(d, 8 H, J = 8.2 Hz, C6H4), 7.19 (d, 8 H, J = 8.2 Hz, C6H4),
6.66 (s, 8 H, Ar), 5.37 (dd, 4 H, J = 3.4 and 1.6 Hz, H-2),
5.30 (dd, 4 H, J = 10.1 and 3.4 Hz, H-3), 5.29 (t, 4 H, J = 9.7
Hz, H-4), 5.11 (d, 4 H, J = 1.6 Hz, H-1), 4.84 (s, 8 H,
ArCH2O), 4.52 (d, 4 H, J = 15.8 Hz, OCH2), 4.49 (d, 4 H,
J = 15.8 Hz, OCH2), 4.29 (dd, 4 H, J = 12.1 and 4.8 Hz, H-
6), 4.10 (dd, 4 H, J = 11.8 and 2.4 Hz, H-6'), 4.15–4.00 (m,
4 H, H-5), 3.98, 2.91 (2 d, 8 H, J = 12.7 Hz, ArCH2Ar), 2.13,
2.07, 2.02, 1.97 (4 s, 48 H, 16 MeCO), 1.03 (s, 36 H,
4Me3C); 13C NMR (75 MHz, CDCl3) : 170.6, 169.9, 169.8,
169.7, 152.2, 144.8, 138.9, 133.8, 121.4, 131.5, 129.7,
125.1, 96.2, 87.3, 83.4, 76.1, 69.5, 69.1, 69.0, 66.1, 55.7,
33.8, 31.5, 31.4, 20.9, 20.8, 20.7, 20.7; HRMS–FAB calcd
for C140H160O44 + Na: 2568.0180 (M + Na)+, found:
2568.0177.
(12) General procedure for the synthesis of
iodoarylcalixarenes 3 and 4: A suspension of the
corresponding calix[4]arene (1 or 2) (0.23 mmol) and NaH
(1.84 mmol) in DMF (10 mL) was kept at r.t. for 30 min.
After this time p-iodobenzyl bromide (1.38 mmol) was
added. The reaction mixture was then heated at 50 °C for 20
h. After cooling the excess of NaH was slowly quenched
with cold methanol. Ether–toluene (3:1, 100 mL) was added
and the resulting solution washed with water (3 21 mL).
After drying over anhyd Na2SO4 the solvent was evaporated
and the residue crystallized from MeOH giving 3 and 4,
respectively.
Physical data for compound 3: 25,26,27,28-tetrakis(4’-
Iodo-benzyloxy)calix[4]arene obtained as a solid (0.287 g,
97%): mp 80–82 ºC; IR (KBr): 1481, 1450, 1128, 1007, 806
cm–1; 1H NMR (300 MHz, CDCl3) : 7.55 (d, 8 H, J = 8.2 Hz,
C6H4I), 6.97 (d, 8 H, J = 8.2 Hz, C6H4I), 6.61–6.52 (m, 12 H,
C6H3), 4.80 (s, 8 H, CH2), 4.12, 2.97 (2 d, 8 H, J = 13.6 Hz,
ArCH2Ar); 13C NMR (75 MHz, CDCl3) : 155.2, 137.6,
137.4, 137.2, 135.1, 131.4, 129.7, 128.5, 122.6, 93.8, 75.8,
31.4; HRMS–FAB calcd for C56H44I4O4 + Na: 1310.9316 (M
+ Na)+; found: 1310.9319.
(14) Kaufman, R. J.; Sidhu, R. S. J. Org. Chem. 1982, 47, 4941.
(15) Roy, R.; Das, K.; Hernández-Mateo, F.; Santoyo-González,
F.; Gan, Z. Synthesis 2001, 1049.
(16) Synthesis of fully deprotected calix-sugars 8 and 9:
Compounds 6 or 7 (0.1 mmol) was dissolved into methanol
(30 mL) to which a catalytic amount of NaOMe was added.
Synlett 2001, No. 11, 1699–1702 ISSN 0936-5214 © Thieme Stuttgart · New York

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F. Pérez-Balderas, F. Santoyo-González
LETTER
The mixture was kept at r.t. for 12 h. NaOMe was
neutralized with Amberlite IR-120 (H+). The resine was
filtered, washed with methanol and the solution evaporated
under vacuum giving the corresponding hydroxylated
derivatives 8 and 9.
Physical Data for 8: 25,26,27,28-tetrakis{4’-[1’’-( -D-
Mannopyranosyl)prop-3’’-ynyl]benzyloxy}calix[4]arene
obtained as a solid (0.112 g, 68%): mp 147–150 °C (dec);
[ ]D +22 (c 0.3, water); IR (KBr): 3400, 1570, 1450, 1059
cm–1; 1H NMR (300 MHz, DMSO-d6) : 7.36 (d, 4 H, J = 8.1
Hz, C6H4), 7.29 (d, 4 H, J = 8.1 Hz, C6H4), 6.58–6.44 (m, 12
H, C6H3), 4.91 (s, 8 H, ArCH2), 4.85 (s, 4 H, H-1), 4.45 (AB
Physical Data for 9: 5,11,17,23-tetra-tert-Butyl-
25,26,27,28-tetrakis{4’-[1’’-O-( -D-manno-
pyranosyl)prop-3’’-ynyl]benzyloxy}calix[4]arene
obtained as a solid (0.133 g, 71%): mp 190–195 °C (dec.)
(from ether) ºC; IR (KBr): 3408, 1510, 1479, 1124,
1059 cm–1; 1H NMR (300 MHz, DMSO-d6) : 7.33 (AB
system, 16 H, J = 8.2 Hz,
C6H2), 4.85
= 13.6 Hz, C6H4), 6.72 (s, 8 H,
(br s, 12 H, CH2O, H-1), 4.48 (AB system, 8 H, J = 16 Hz,
PhCH2), 4.05 (d, 4 H, J = 12.7 Hz, ArCH2Ar), 3.70–3.29
(several m, 24 H, H-2, -3, -4, -5, -6, -6'), 2.85 (d, 4 H,
J = 12.9 Hz, ArCH2Ar), 1.00 (s, 36 H, 4Me3C); 13C NMR
(75 MHz, DMSO-d6) :152.1, 143.9, 138.5, 133.3, 131.4,
129.6, 124.8, 121.2, 116.1, 98.4, 85.8, 85.5, 74.4, 70.9, 70.1,
66.9, 61.1, 53.7, 33.5, 31.1; HRMS–FAB calcd for
system, 8 H, J = 16.1 Hz,
= 21.8 Hz; CH2 O), 4.05 (d, 4
H, J = 13.2 Hz, ArCH2 Ar), 3.68–3.28 (m, 24 H, H-2, -3, -4,
-5, -6 , -6'), 2.90 (d, 4 H, J = 13.4 Hz, ArCH2Ar); 13C NMR
(75 MHz, DMSO-d6) : 160.2, 154.5, 137.9, 134.7, 131.5,
131.4, 129.7, 128.8, 127.9, 121.4, 98.3, 85.9, 85.3, 74.4,
70.9, 70.1, 66.8, 61.1, 53.6, 30.7; HRMS–FAB calcd for
C92H96O28 + Na: 1671.598 (M + Na)+; found: 1671.606.
C
108H128O28 + Na: 1895.8480 (M + Na)+; found: 1895.3510.
(17) García-López, J. J.; Hernández-Mateo, F.; Isac-García, J.;
Kim, J. M.; Roy, R.; Santoyo-González, F. J. Org. Chem.
1999, 64, 522.
Synlett 2001, No. 11, 1699–1702 ISSN 0936-5214 © Thieme Stuttgart · New York