A strategy for ready preparation of glycolipids for multivalent presentation

Article abstract of DOI:10.1021/ol0511981

(Chemical Equation Presented) The olefinic residue of n-pentenyl glycosides serves as the trigger for regioselective construction of higher saccharides and then for elaboration in multivalent glycolipids.

Full text of DOI:10.1021/ol0511981

ORGANIC
LETTERS
2005
Vol. 7, No. 18
3841-3843
A Strategy for Ready Preparation of
Glycolipids for Multivalent Presentation
Jun Lu,† Bert Fraser-Reid,*,† and Channe Gowda‡
Natural Products and Glycotechnology Research Institute, Inc., 595 F Weathersfield
Road, Fearrington Post 595 F, Pittsboro, North Carolina 27312, and Department of
Biochemistry and Molecular Biology, The PennsylVania State College of Medicine,
500 UniVersity DriVe, Hershey, PennsylVania 17033
dglucose@aol.com
Received May 21, 2005 (Revised Manuscript Received July 25, 2005)
ABSTRACT
The olefinic residue of n-pentenyl glycosides serves as the trigger for regioselective construction of higher saccharides and then for elaboration
in multivalent glycolipids.
In recent years glycolipid presentation by CD1 protein has
emerged as an important aspect of antigen recognition.1,2
Thus, NKT cells are characterized by a narrow T cell antigen
receptor (TCR) repertoire that recognizes glycolipid antigens,
resulting in the formation of monomorphic CD1d antigen-
presenting cells, which have a unique capacity to rapidly
produce large amounts of both T helper (Th) 1 and Th2
cytokines. Major interest therefore centers around the roles
that CD1 molecules play in host defense3 by controlling the
development and function of T cell receptors. Their mode
of action is consistent with a structural architecture that
possesses hydrophilic and hydrophobic domains.4-6 The
lipids that were studied originally were mycolic acids. Moody
et al.7 found that a variety of lipid antigens were bound
“relatively nonspecifically”, there being no apparent depen-
dence on the structural variations in the hydrophobic tails
of the test candidates. Indeed a timely crystal structure of a
member of the CD1 family by Zeng et al.8 revealed the
(4) See, for example: Grant, E. P.; Degano, M.; Rosat, J. P.; Stenger,
S.; Modlin, R. L.; Wilson, I. A.; Porcelli, S. A.; Brenner, M. B. J. Exp.
Med. 1999, 189, 195-205. Beckman, E. M.; Melian, A.; Behar, S. M.;
Sieling, P. A.; Chatterjee, D.; Furlong, S. T.; Matsumoto, R.; Rosat, J. P.;
Modlin, R. L.; Porcelli, S. A. J. Immunol. 1996, 157, 2795-2803.
(5) Sieling, P. A.; Chatterjee, D.; Porcelli, S. A.; Prigozy, T. I.;
Mazzaccaro, R. J.; Soriano, T.; Bloom, B. R.; Brenner, M. B.; Kronenberg,
M.; Brennan, P. J. Science 1995, 269, 227-230. Moody, D. B.; Ulrichs,
T.; Muhlecker, W.; Young, D. C.; Gurcha, S. S.; Grant, E. P.; Rosat, J.;
Brenner, M. D.; Costello, C. E.; Besra, G. S.; Porcelli, S. A. Nature 2000,
404, 884-888. Moody, D. B.; Reinhold: B. B.; Guy, M. R.; Beckman, E.
M.; Frederique, D. E.; Furlong, S. T.; Ye, S.; Reinhold: V. N.; Sieling, P.
A.; Modlin, R. L. et al. Science 1997, 278, 283-286. Moody, D. B.; Besra,
G. S.; Wilson, I. A.; Porcelli, S. A. Immunology 1999, 172, 285-296.
(6) Porcelli, S. A. Nat. Immunol. 2001, 2, 191-192.
† Natural Products and Glycotechnology Research Institute, Inc. (NPG
is a private nonprofit organization located at Centennial Campus, North
Carolina State University, Raleigh, NC.)
‡ The Pennsylvania State College of Medicine.
(1) Brigl, M.; Brenner, M. B. Annu. ReV. Immunol. 2004, 22, 817-890.
(2) Dutronc, Y.; Porcelli, S. A. Tissue Antigens 2002, 60, 337-353.
(3) See, for example: McMichael, A. J.; Pilch, J. R.; Galfre, G.; Mason,
D. Y.; Febre, J. W.; Milstein, C. Eur. J. Immunol. 1979, 9, 205-210.
Bernard, A.; Bournsell, L. Hum. Immunol. 1984, 11, 1-10. Calabi, F.; Jarvis,
M.; Martin, L.; Mulstein, C. Eur. J. Immunol. 1989, 19, 285-292. Beckman,
E. M.; Porcelli, S. A.; Morita, C. T.; Behar, S. M.; Furlong, S. T.; Brenner,
M. B. Nature 1994, 372, 691-694. Prigozy, T. I.; Naidenko, O.; Qasba,
P.; Elewaut, D.; Brossay, L.; Khurana, A.; Natori, T.; Koezuka, Y.; Kulkarni,
A.; Kronenberg, M. Science 2001, 291, 664-667.
(7) Moody, D. B.; Reinhold: B. B.; Guy, M. R.; Beckman, E. M.;
Frederique, D. E.; Furlong, S. T.; Ye, S.; Reinhold: V. N.; Sieling, P. A.;
Modlin, R. L.; Besra, G. S. Science 1997, 278, 283-286.
(8) Zeng, Z.; Castano, A. R.; Segelke, B. W.; Stura, E. A.; Peterson, P.
A.; Wilson, I. A. Science 1997, 277, 339-345.
10.1021/ol0511981 CCC: $30.25
© 2005 American Chemical Society
Published on Web 08/05/2005

presence of a deep hydrophobic groove that could accom-
modate the aliphatic moiety of a glycolipid.
Scheme 1
The glycolipids that have provided the experimental basis
for interpreting CD1 function include glycosylphosphatidyl
inositols (GPIs),9,10 lipoarabinomannans (LAMS),5 and other
mycobacterial specimens. These phosphoinositides are as-
sociated with some of the world’s oldest, most dreaded, and
most obdurate diseases, including malaria and tuberculosis.
The synergy of the latter with HIV infection11 raises the dread
level manyfold.
These biological insights come amidst structural insights
into the importance of multivalent presentation of carbohy-
drate epitopes. Thus, Lee’s seminal experiments12 on the
biological effect of sugar clusters laid the foundation13 for
the concept of multivalency and hence for a rational approach
to the synthesis of glycolipid test candidates that are
amenable to supramolecular assembly.
Our long-standing synthetic work on phosphoinositides,14
GPIs15 and mycobacterial glycolipids16 has sensitized us to
CD1 science, and fortunately, our synthetic strategies lend
themselves to the preparation of candidates for multivalent
presentation. In this manuscript we report some ready routes.
At the distal end of membrane-anchored GPIs (e.g., 1)
is a trimannan array, the middle unit of which bears a
phosphoethanolamine residue.17 A protein is sometimes
attached to the latter; however, Ralton and McConville have
noted that “a significant proportion of GPI synthetic output
of a cell is NOT directed to protein anchoring,” which raises
questions as to their purpose.18
Our synthesis of the distal trimannan construct 7 described
in Scheme 2 employed the readily prepared n-pentenyl ortho
(9) Schofield, L.; McConville, M. J.; Hansen, D.; Campbell, A. S.; Fraser-
Reid, B. Science 1999, 283, 225-229.
(10) Molano, A.; Park, S. H.; Chiu, Y. H.; Nosseir, S.; Bendelac, A.;
Tsuji, M. Immunology 2000, 164, 5005-5009. Duthie, M. S.; Wleklinski-
Lee, M.; Smith, S.; Nakayama, T.; Taniguchi, M.; Kahn, S. J. Infect. Immun.
2002, 70, 36-48. Sebastian, J.; Woods, A. S.; Yewdell, J. W.; Bennink, J.
R.; De Dilva, A. D.; Boesteanu, A.; Balk, S. P.; Cotter, R. J.; Brutkiewicz,
R. R. Science 1998, 279, 1541-1544.
(11) Murray, J. F. Bull. Int. Union Tuberculosis Lung Dis. 1991, 66,
199-201. Stanford, J. L.; Grange, J. M.; Pozniak, A. Lancet 1991, 338,
557-558. Festenstein, F.; Grange, J. M. J. Appl. Bacteriol. 1991, 71, 19-
30. Watson, J.; Gill, O. N. Br. J. Med. 1991, 300, 63-65.
(12) Lee, Y. C.; Lee, R. J. Acc. Chem. Res. 1995, 28, 321-327.
(13) Kiessling, L. L.; Pohl, N. L. Chem. Biol. 1996, 3, 71. Roy, R. Curr.
Opin. Struct. Biol. 1996, 6, 692-702. Mammen, M.; Choi, S. K.; Whitesides,
G. M. Angew. Chem., Int. Ed. 1998, 37, 2754-2794. Roy, R.; Kim, J. M.
Angew. Chem., Int. Ed. 1999, 38, 369-372.
(14) Yu, K.-L.; Fraser-Reid, B. Tetrahedron Lett. 1988. 29, 979-982.
Yu, K.-L.; Ko, K.-Y.; Fraser-Reid, B. Synth. Commun. 1988, 18, 465-468
Schlueter, U.; Lu, J., Fraser-Reid, B. Org. Lett. 2003, 5, 255-257,
(15) Roberts, C.; Madsen, R.; Fraser-Reid, B. J. Am. Chem. Soc. 1995,
117, 1546-1553. Madsen, R.; Udodong, U. E.; Roberts, C.; Mootoo, D.
R.; Konradsson, P.; Fraser-Reid, B. J. Am. Chem. Soc. 1995, 117, 1554-
1565. Campbell, A. S.; Fraser-Reid, B. J. Am. Chem. Soc. 1995, 117,
10387-10388. Lu, J.; Jayaprakash, K. N.; Fraser-Reid, B. Tetrahedron Lett
2004, 44, 879-882. Lu, J.; Jayaprakash, K. N.; Schlueter, U.; Fraser-Reid,
B. J. Am. Chem. Soc. 2004, 126, 7540-7547.
ester (NPOE) 2a as a convenient sole source progenitor.
Perbenzylation gave 2b, while selective silylation prior to
benzylation gave 2c (Scheme 1). Treatment of 2b with
TBDMSOTf brought about rearrangement of the ortho ester19
and provided 3b in near quantitative yield. The n-pentenyl
glycoside (NPG) 3b and NPOE 2c are both potential glycosyl
donors, but because Yb(OTf)3/NIS reacts chemospecifically
with NPOEs,19 formation of disaccharide 4a was assured.
Removal of the benzoate group afforded 4b, and a second
chemospecific reaction, this time with 2b, gave the desired
trisaccharide 5a, from which the benzylated counterpart 5c
was obtained by routine transformations.
The chemoselectivity in the reaction of precursors 2c and
3b was now appreciated since the olefinic residue of 5c could
be dihydroxylated, esterified, and desilylated, which allowed
insallation of the phosphoethanolamine residue in 6a. Hy-
drogenolysis then afforded compound 6b.
(16) Jayaprakash, K. N.; Lu, J.; Fraser-Reid, B. Bioorg. Med. Chem.
Lett. 2004, 14, 3815-3819. Lu, J.; Fraser-Reid, B. Chem. Commun. 2005,
862-864. Jayaprakash, K. N.; Lu, J.; Fraser-Reid, B. Angew. Chem., Int.
Ed. In press.
(18) Ralton, J. E.; McConville, M. J. Biol. Chem. 1998, 273, 4245-
4257.
(19) Jayaprakash, K. N.; Fraser-Reid, B. Synlett 2004, 301-305.
Jayaprakash, K. N.; Fraser- Reid, B. Org. Lett. 2004, 6, 4211-4214.
(17) McConville, M.; Ferguson, M. J. Biochem. J. 1993, 294, 305-324.
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Org. Lett., Vol. 7, No. 18, 2005

Scheme 2
Scheme 3
10 under the agency of DCC and DMAP to produce
compound 13.
The strategy for the di- and trivalent presentations in
Schemes 2 and 3 are different and illustrate the versatility
of n-pentenyl derivatives for ready preparation of multivalent
constructs. Our studies along this line are continuing, and
the biological effects of these multivalent constructs are
currently being tested.
The n-pentenylated trisaccharides 5c also served as precur-
sor for the di- and trivalent neoglycolipids. Thus, Grubb
olefin metathesis20 provided the bis-disaccharide 7, which
was subjected to similar steps as described above, to obtain
the divalent construct 8. The latter was then processed, along
the lines in Scheme 2, to give the bis-phosphodiester 9.
Our strategy for the trivalent construct made use of two
n-pentenyl glycosides in different ways. First, the olefinic
unit of 5c was cleaved to provide the carboxylic acid 10.
Monosaccharides have served as scaffolds for displaying bio-
probes of various sorts,21 and so we made use of our recently
synthesized22 n-pentenyl arabinoside 11 (Scheme 3). Hy-
droxylation and esterification of the resulting diol gave the
diester 12a, and hydrogenolysis freed the hydroxyl groups
in 12b. The latter was then acylated with the glycoconjugate
Acknowledgment. B.F.-R. thanks the National Science
Foundation (CHE-0236946) and The Mizutani Foundation,
and C.G. thanks NIAID, NIH (AI41139) for support.
Supporting Information Available: Experimental pro-
cedures and characterization data for all new compounds.
This material is available free of charge via the Internet at
http://pubs.acs.org.
OL0511981
(21) Hirshman, R.; Duery, L.; Smith, A. B., III J. Org. Chem. 2000, 65,
8307-8316. Hanessian, S.; Hoornaert, C.; Pernet, A. G.; Nadzan, A. M.
Carbohydr. Res. 1985, 137, C14-C16. Kieburg, C.; Dubker, M.; Lindhorst,
T. K. Synlett 1997, 1447-1449. Turbull, W. B.; Stoddart, J. F.; Rev. Moleen.
Biotechnology 2002, 90, 231-255.
(20) Grubbs, R. H. Tetrahedron 2004, 60, 7117-7140.
Org. Lett., Vol. 7, No. 18, 2005
(22) Lu, J.; Fraser-Reid, B. Org. Lett 2004, 6, 3051-3054.
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