Synthesis of the Glycopeptidolipid of Mycobacterium avium Serovar 4: First Example of a Fully Synthetic C-Mycoside GPL

Article abstract of DOI:10.1021/jo030304e

The preparation of the glycopeptidolipid (GPL) present in the cell wall of Mycobacterium avium Serovar 4, namely 3,4-di-O-Me-α-L-Rhap-(1→ 1){R-C₂₁H₄₃CH(OH)CH₂CO-D-Phe-[4-O-Me-α -L-Rhap-(1→4)-2-O-Me-α-L-Fucp-(1→3)-α-L-Rhap-

Full text of DOI:10.1021/jo030304e

Syn th esis of th e Glycop ep tid olip id of Mycoba cter iu m a viu m
Ser ova r 4: F ir st Exa m p le of a F u lly Syn th etic C-Mycosid e GP L
Thorsten Heidelberg and Olivier R. Martin*
Department of Chemistry, State University of New York, Binghamton, New York 13902-6016, and
Institut de Chimie Organique et Analytique, Universite´ d’Orle´ans, 45067 Orle´ans, France
olivier.martin@univ-orleans.fr
Received September 25, 2003
The preparation of the glycopeptidolipid (GPL) present in the cell wall of Mycobacterium avium
Serovar 4, namely 3,4-di-O-Me-R-L-Rhap-(1f1){R-C21H43CH(OH)CH2CO-D-Phe-[4-O-Me-R-L-Rhap-
(1f4)-2-O-Me-R-L-Fucp-(1f3)-R-L-Rhap-(1f2)-6-deoxy-R-L-Talp-(1f3)]-D-allo-Thr-D-Ala-L-Alaol} (1),
is described. The synthesis was based on the disconnection of the final structure into four building
blocks, an L-rhamnosyl pseudodipeptide, a 6-deoxy-L-talosyl dipeptide, a trisaccharide donor, and
a 3-hydroxyalkanoic acid. The key steps are the creation of the glycosidic linkage between the
trisaccharide donor, used as a pentenyl glycoside, and the 6-deoxy-L-talose unit of an appropriate
D-Phe-O-(6-deoxy-L-talosyl)-D-allo-Thr derivative and the final coupling of the two glycodipeptide
fragments. Pentenyl glycosides were shown to provide useful donors in several glycosylation steps.
This work constitutes the first synthesis of the full structure of a so-called “polar mycoside C”
GPL.
In tr od u ction
with partial syntheses have been published and are
summarized in recent reviews.4a,5 The core structure of
glycopeptidolipids of the ‘polar mycosides C’ family, to
which the M. avium GPLs belong, consists of a pseudo-
tetrapeptide containing L-alaninol as C-terminal unit,
D-Ala, D-allo-Thr, and D-Phe, N-acylated at the N-
terminal position with a fatty acid residue, and glycosy-
lated at both hydroxyl groups: conserved sugar units are
a 3,4-di-O-methyl-R-L-rhamnopyranosyl group (at L-alan-
inol) and an O-(R-L-rhamnopyranosyl)-(1f2)-6-deoxy-R-
L-talopyranose disaccharide O-linked to D-allo-Thr.4a,6
Remarkably, very few synthetic studies have been dedi-
cated to complete GPL structures. While numerous
syntheses of antigenic oligosaccharide fragments of my-
coside GPLs have been reported,7,8 the preparation of the
core pseudotetrapeptide has been achieved by Gurjar et
al.,9 and the only example of a mycoside-type glycopeptide
(from M. fortuitum) carrying sugar residues at both
hydroxylated sites has been described by this group.10
We wish to report in this paper the first synthesis of a
complete N-acylated, fully glycosylated mycoside-type
GPL, the GPL of Mycobacterium avium serovar 4 (1);4b
this structure is of particular interest because it is the
Diseases caused by mycobacterial infections continue
to constitute serious health threats. The most common
species are Mycobacterium tuberculosis and Mycobacte-
rium leprae, the pathogens responsible for tuberculosis
and leprosy, respectively. Tuberculosis is the leading
cause of death from a single infectious agent, and its
incidence is increasing as a result of the emergence of
multidrug-resistant M. tuberculosis strains.1 Other rep-
resentative mycobacteria such as Mycobacterium intra-
cellulare and different variants of the Mycobacterium
avium complex have been found to cause disseminated
infections in many AIDS victims. Up to 50% of the AIDS
patients are reported to be infected with these intracel-
lular parasites.2 The highly impermeable cell wall of
mycobacteria3 contains numerous immunogenic glycolip-
ids of great structural diversity.4 The polar glycopepti-
dolipids (GPL) of the M. avium complex are of particular
interest because of their high antigenicity and their
species’ specificity:5 GPLs are the chemical markers of
the 31 distinct serovars known for the M. avium group.
Several studies dealing with the structural analysis and
the biological properties of these compounds as well as
(6) Laneelle, G.; Asselineau, J . Eur. J . Biochem. 1968, 5, 487-491.
(7) Liptak, A.; Borbas, A.; Bajza, I. Med. Res. Rev. 1994, 14, 307-
352 and references cited therein.
(1) Dye, C.; Scheele, S.; Dolin, P.; Pathania, V.; Raviglione, M. C.
J AMA 1999, 282, 677-686.
(2) Collins, F. M. Microbiol. Rev. 1989, 2, 360-370.
(3) Brennan, P. J .; Nikaido, H. Annu. Rev. Biochem. 1995, 64, 29-
63.
(8) See, for example: (a) Gurjar, M. K.; Viswanadham, G. J .
Carbohydr. Chem. 1991, 10, 481-485. (b) Ziegler, T. Carbohydr. Res.
1994, 253, 151-166. (c) Zegelaar-J aarsveld, K.; van der Plas, S. C.;
van der Marel, G. A.; van Boom, J . H. J . Carbohydr. Chem. 1996, 15,
561-610. (d) Varga, Z.; Bajza, I.; Batta, G.; Liptak, A. Tetrahedron
Lett. 2001, 42, 5283-5286. (e) Varga, Z.; Bajza, I.; Batta, G.; Liptak,
A. Tetrahedron Lett. 2002, 43, 3145-3148.
(4) (a) Aspinall, G. O. Adv. Carbohydr. Chem. Biochem. 1995, 51,
169-242 and references cited therein. In particular, see: (b) McNeil,
M.; Tsang, A. Y.; Brennan, P. J . J . Biol. Chem. 1987, 262, 2630-2635.
The native GPL of M. avium Serovar 4 is apparently di-O-acetylated,
but the position of the acetyl groups is not known, and these groups
are not necessary for antigenicity of the GPL.
(9) Gurjar, M. K.; Saha, U. K. Tetrahedron Lett. 1991, 32, 6621-
6624.
(5) Chatterjee, D.; Khoo, K. H. Cell Mol. Life Sci. 2001, 58, 2018-
2042.
(10) Gurjar, M. K.; Saha, U. K. Bioorg. Med. Chem. Lett. 1993, 3,
697-702.
10.1021/jo030304e CCC: $27.50 © 2004 American Chemical Society
Published on Web 03/05/2004
2290
J . Org. Chem. 2004, 69, 2290-2301

Fully Synthetic C-Mycoside GPL
F IGURE 1. Buiding blocks for the synthesis of 1 (PG ) protecting group).
SCHEME 1
variant most frequently found in AIDS patients with
disseminated mycobacterial infections.4
Discu ssion
After extensive preliminary investigations, and on the
basis of the previous work of Gurjar9 on the core
pseudopeptide and of van Boom et al.11 on the tetrasac-
charide component, we determined that the best strategy
for the total synthesis of 1 consisted in assembling the
building blocks described in Figure 1, namely a rham-
nosylated pseudodipeptide (A), a 6-deoxytalosylated dipep-
tide (B), a trisaccharide corresponding to sugar units b,
c, and d of 1 (C), and a 3-hydroxyalkanoic acid (D). A
more complex building block was to be achieved by
linking B to C, followed by N-acylation with D, before
the final, crucial peptide coupling between the resulting
glycolipodipeptide and A. The disconnection of the trisac-
charide b-c-d from the talosylated D-allo-threonine
fragment proved to be essential for the success of the
synthesis.
Bu ild in g Block A (Sch em e 1). A synthesis of com-
pound 10, the precursor of glycopeptide building block
A (11), has been reported by Gurjar.9 The preparation of
10 was simplified as follows. First, the trichloroacetimi-
date of 2-O-acetyl-3,4-di-O-methyl-L-rhamnopyranose (com-
pound 612) was prepared in four steps from acetobromo-
L-rhamnose 213 (instead of eight steps from methyl R-L-
rhamnopyranoside12) by way of the O-benzyl ortho ester
3b: compound 3b was obtained from 2 by a standard
protocol for ortho ester formation,14 thus giving 3a
followed by a one-pot acetyl to methyl group exchange.
Hydrogenolysis of 3b in aqueous dioxane gave hemiacetal
4 in one step, and 4 was then converted into glycosyl
donor 6. Interestingly, a different result was obtained if
the hydrogenation was carried out in anhydrous ethyl
acetate: under these conditions, the reaction of 3b led
predominantely to anhydrorhamnitol 5 instead of 4. The
mechanism for this transformation remains uncertain.
The synthesis of 10 was completed by glycosylating the
preformed pseudodipeptide 9 with trichloroacetimidate
6. Compound 9 can be prepared either by coupling Z-L-
Ala with commercial L-alaninol using a standard peptide
protocol or, in a much less expensive way, by the sodium
borohydride-mediated reduction15 of Z-D-Ala-L-Ala-OMe
8. The glycosylation was performed in the presence of
TMSOTf and gave glycodipeptide 10 in 72% yield. The
(12) Gurjar, M. K.; Saha, U. K. Tetrahedron 1992, 48, 4039-4044.
(13) Fischer, E.; Bergmann, M.; Rabe, A. Ber. 1920, 53, 2362-2388.
(14) Mazurek, M.; Perlin, A. S. Can. J . Chem. 1965, 43, 1918-1923.
(15) (a) Kubota, M.; Nagase, O.; Yajima, H. Chem. Pharm. Bull.
1981, 29, 1169-1171. (b) Sohai, M.; Oyamada, H.; Takase, M. Bull.
Chem. Soc. J pn. 1984, 57, 2327-2328. (c) Kokotos, G. Synthesis 1990,
299-301.
(11) Zuurmond, H. M.; Veenemann, G. H.; van der Marel, G. A.;
van Boom, J . H. Carbohydr. Res. 1993, 241, 153-164.
J . Org. Chem, Vol. 69, No. 7, 2004 2291

Heidelberg and Martin
SCHEME 2
synthetic sequence was further shortened by replacing
the O-benzyl ortho ester intermediate 3b by the corre-
sponding O-4-pentenyl ortho ester 7b: according to
Fraser-Reid et al.,16 O-4-pentenyl ortho esters can indeed
be used directly as glycosyl donors in the presence of NIS
and TMSOTf.
Compound 7b was prepared via 7a under the same
conditions as 3b and was used directly as the acceptor
in the glycosylation of pseudodipeptide 9. The reaction
was performed using NIS and TMSOTf as promoters and
gave 10 in 81% yield; by this sequence, compound 10 is
accessible in only three steps from 2 and 9. Glycodipep-
tide 10 was then deprotected in two steps to afford free
amine 11.
Bu ild in g Block B (Sch em e 2). The preparation of
the core 6-deoxy-L-talosyl dipeptide is displayed in Scheme
2. The formation of the talosyl donors followed studies
previously reported by several authors. However, instead
of the more commonly used methyl17 and benzyl rham-
nosides,18 we based our synthesis on 4-pentenyl glyco-
sides, which are readily available and can be used directly
as glycosyl donors, thus shortening the synthesis. 4-Pen-
tenyl R-L-rhamnopyranoside precursor 12 was prepared
in 94% yield from L-rhamnose by reaction with 4-penten-
1-ol under acidic conditions followed by acetonation of
the pair of cis OH groups. Oxidation at C-4 of rhamnoside
12 followed by sodium borohydride reduction of the
resulting hexos-4-uloside 13 provided access to the L-talo
series (compound 14). With respect to the double bond
present in the pentenyl group, oxidation could only be
performed using Swern conditions or a Cr(VI) oxidant
while Ru(VIII)-based reagents could not be used. To
perform the selective glycosylation at position 2 of the
6-deoxy-L-talose unit later in the synthesis, the selective
protection of positions 3 and 4, and of position 2, was
required. This could be achieved either by acetonation
or by benzylation. In the first method, deacetonation of
14 followed by reacetonation11 of triol 19 gave 20 in
reasonable yield (50% overall yield from L-rhamnose) in
addition to a minor amount of regenerated isomer 14
(13%). The acid-catalyzed rearrangement of 14 could be
achieved as well, but provided 20 in lower yield. An
important change of conformation of the taloside was
observed after formation of the 3,4-O-linked bicyclic
acetal. The coupling constant between H-1 and H-2
indicated an almost diaxial orientation of these protons,
consistent with a boat or twist-boat conformation of the
ring instead of the more common chair form of the
precursors.
(16) (a) Fraser-Reid, B.; Udodong, U. E.; Wu, Z.; Ottosson, H.;
Merritt, J . R.; Rao, C. S.; Roberts, C.; Madsen, R. Synlett 1992, 927-
942. (b) Fraser-Reid, B.; Madsen, R. In Preparative Carbohydrate
Chemistry; Hanessian, S., Ed.; Marcel Dekker: New York, 1996; pp
339-358.
(17) (a) Gan, Z.; Kong, F. Carbohydr. Res. 1995, 270, 211-216. (b)
Gurjar, M. K.; Viswanadham, G. Tetrahedron Lett. 1991, 32, 6191-
6194.
For the benzyl protection scheme, compound 14 was
benzylated at position O-4, to give 15, and compound 15
was deacetonated. The glycoside 16 thus obtained was
then submitted to regioselective benzylation by way of a
(18) Aspinall, G. O.; Takeo, K. Carbohydr. Res. 1983, 121, 61-78.
2292 J . Org. Chem., Vol. 69, No. 7, 2004

Fully Synthetic C-Mycoside GPL
2,3-O-stannylidene intermediate.17a,18 The selectivity of
this reaction, however, was low, and provided only a
small excess of the desired isomer 17a (ratio 17a /17b ≈
12:11). Compound 17a could be separated by flash
chromatography and isolated in 41% yield. Finally, both
17a and 20 were chloroacetylated at the remaining free
2-OH group to give the donors 18 and 21. The availability
of two precursors carrying different protecting groups in
the 6-deoxy-L-talose unit turned out to be critical in later
stages of the synthesis.
SCHEME 3
The D-allothreonine precursor 22 was prepared from
benzyl crotonate by the efficient asymmetric synthesis
developed by Shao and Goodman;19 the azido group of
22 could be hydrogenolyzed selectively in the presence
of Pt on charcoal to form D-allothreonine benzyl ester
hydrochloride 23. The choice of the solvent (dioxane) was
critical for this reaction. IIDQ-mediated coupling of 23
with D-phenylalanine derivative 2420 furnished the de-
sired peptide 25 in good yield (79%).
The glycosylation of 25 with both pentenyl glycosides
18 and 21 was then investigated using NIS and TMSOTf
as promoters. Both reactions gave the expected glyco-
dipeptide 26 and 28 in good yield and with complete
R-stereoselectivity as a result of the presence of an ester
at position 2 of the donors. Like pentenyl ortho ester 7b,
both 18 and 21 required more than 1 equiv of Lewis acid
in addition to NIS to promote the glycosylation. Immedi-
ate purification of 28 was required to avoid the decom-
position of the product, probably as a result of the
sensitivity of the isopropylidene group toward traces of
iodine21 formed in the course of the reaction. While 26
did not show a similar sensitivity, we isolated a minor
side product (9%) in the glycosylation with 18, compound
30, which resulted from the addition of NIS to the
pentenyl group. Such behavior of pentenyl glycosides is
quite rare. Dechloroacetylation of 26 and 28 using
hydrazinodithiocarbonate or thiourea furnished the ac-
ceptors 27 and 29 ready for the coupling with trisaccha-
ride donors.
SCHEME 4
Bu ild in g Block C (Sch em es 3 a n d 4). For the
synthesis of the trisaccharide donor, two different strate-
gies were investigated, differing in the order of glycosy-
lation. In the first approach (Scheme 3), a disaccharide
donor, corresponding to residues d-c, was coupled to a
monoglycoside acceptor (b), whereas in the second (Scheme
4), more common, approach, a monosaccharidyl donor (d)
was attached to a disaccharide acceptor (c-b). The second
approach proved more efficient.
which could be separated chromatographically and iso-
lated in 63% and 26% yield, respectively. Glycosylation
of 32a with the trichloroacetimidate 3423 provided the
disaccharide 35 as the R-anomer exclusively. This com-
pound was then coupled to benzyl rhamnoside 36 to give
trisaccharide 37 in modest overall yield (42%).
Stannylidene-mediated regioselective acetylation of
pentenyl fucoside 3122 gave monoacetates 32a and 32b,
(22) (a) J ain, R. K.; Locke, R. D.; Matta, K. L. Carbohydr. Res. 1991,
212, C1-C3. (b) Debenham, J . S.; Rodebaugh, R.; Fraser-Reid, B. J .
Org. Chem. 1997, 62, 4591-4600.
(23) Aspinall, G. O.; Crane, A. M.; Gammon, D. W.; Ibrahim, I. H.;
Khare, N. K.; Chatterjee, D.; Rivaire, B.; Brennan, P. J . Carbohydr.
Res. 1991, 216, 337-355.
(19) Shao, H.; Goodman, M. J . Org. Chem. 1996, 61, 2582-2583.
(20) Carson, J . F. Synthesis 1981, 268-270 (L-analogue).
(21) Szarek, W. A.; Zamojski, A.; Tiwari, K. N.; Ison, E. R. Tetra-
hedron Lett. 1986, 27, 3827-3830.
J . Org. Chem, Vol. 69, No. 7, 2004 2293

Heidelberg and Martin
CHART 1
(R)-3-hydroxylignoceric acid 49. However, this compound
proved to be very poorly soluble in organic solvents,
requiring elevated temperature for dissolution. To im-
prove its solubility, the amphiphilicity was reduced by
protecting the hydroxyl group. The alcohol function of 49
was benzylated by the method of Nishizawa30 to give 50
and the ester was saponified. Although the resulting acid
51 could be coupled to amines using a coupling reagent
like EEDQ, its solubility in organic solvents remained
very poor. Furthermore, the chemoselectivity of the
reaction with EEDQ was not good as it led to the desired
fatty acyl amides contaminated by the corresponding
ethyl carbamate and was only moderately improved using
the isobutyl homologue IIDQ.
Although 37 could not be purified to homogeneity, it
was hydrogenolyzed and gave pure reducing trisaccharide
38 after chromatography. However, the conversion of 38
into the corresponding trichloroacetimidate failed, and
this approach was therefore abandoned.
A better solubility for the lipid building block was
achieved by converting the acid 51 into its acyl chloride
52. Since the preparation of 52 was rather long, we
looked for a shorter alternative. In particular, we at-
tempted to combine the necessary protection of the
3-hydroxyl group with the activation of the acid. Phos-
genation of 49 led to the well-soluble, intramolecular
mixed anhydride 53, which appeared to be a suitable
reagent for our purpose. The reaction of 53 with a
glycopeptide amine furnished a single product in high
yield, but the analysis of this product revealed that it
was an urea-type dimer of the amine, R-NHCONH-R.
Thus, instead of acting as an acylating agent, 53 appears
to behave as a phosgene substitute. Acylation reactions
will therefore be performed with the acyl chloride 52.
F in a l Assem bly (Sch em e 5). For the final assembly
of the GPL, the first step was the glycosylation of the
talosylated allothreonine-containing glycopeptide (build-
ing block B) with the trisaccharide donor (building block
C). Initially, we investigated the glycosylation of glyco-
peptide 29 with trisaccharide donor 45 in the presence
of NIS/TMSOTf. The reaction required an excess Lewis
acid and led to a complex mixture, from which an
unexpected product having the constitution of the origi-
nal dipeptide carrying a disaccharide was isolated in 30%
yield. This product was not further investigated. The
same product was also obtained using the less sensitive
benzylated glycopeptide 27 as the acceptor. The coupling
process could not be improved by changing the temper-
ature or using solutions of both coupling reagents.11
To use milder conditions for the key glycosylation step,
we used the “armed” donor 46 instead of 45. With IDCP
as the promoter, compound 27 could be successfully
glycosylated, and the tetrasaccharidyl dipeptide 54 was
isolated in 60% yield (200 mg scale) (Scheme 5). The
reaction, however, was not quite complete and some
starting material was recovered (27 in 19% yield). It
should be noted that with NIS/Lewis acid as coupling
reagents, the reaction provided only the unidentified
product mentioned above. The R-configuration of the
newly formed glycosidic bond was confirmed by a C-H-
coupling constant of about 170 Hz at the anomeric center.
To link the lipidic residue (building block D), the
N-terminal position of the glycopeptide 54 was depro-
tected using zinc in a buffered solution20 and the resulting
amine 55 was acylated with acyl chloride 52 to give
glycopeptidolipid 56 (50% for the two steps). Selective
Another type of trisaccharide donor was sought. With
respect to our favorable experience in glycosylations with
4-pentenyl glycosides, we focused our efforts on the
synthesis of a 1-O-pentenyl trisaccharide. Thus, it was
envisaged to create the linkage between sugar units b
and c by way of a thioglycoside-mediated reaction, unit
b carrying a disarmed pentenyl glycoside, and the linkage
between units c and d using a trichloroacetimidate. A
high R-selectivity of the critical coupling with the 2-OMe
fucose derivative was expected on the basis of previous
work by Van Boom.11 2-O-methyl thiofucoside 3924 was
regioselectively benzylated11 and subsequently chloro-
acetylated to give donor 41. Unlike previous acetylations,
the benzylation was highly selective. Glycosylation of
4-pentenyl rhamnoside 42 with 41 using biscollidine
iodonium perchlorate (IDCP) as promoter gave disaccha-
ride 43 (60%), as R-anomer only, which was then dechlo-
roacetylated to give 44, and glycosylated with trichloro-
acetimidate 34 (∼100%). By this approach, the pentenyl
trisaccharide 45 was obtained in good overall yield. To
rearm the donor, compound 45 was deacetylated and
subsequently benzylated at the four free OH positions
to give 46 in 66% yield.
Bu ild in g Block D (Ch a r t 1). The lipidic component
of mycoside C-type GPLs is an acyl group of widely
diverse chain length (C28 is typical), saturated or mo-
nounsaturated, and carrying a 3-hydroxy or a 3-methoxy
group.4,25 The configuration at C-3 is commonly R, as in
â-hydroxyacyl groups of lipid A glycolipids.26 On the basis
of starting material availability and desire to develop a
synthesis applicable to a wide range of fatty acids, we
chose to attach to the glycopeptide an (R)-3-hydroxytet-
racosanoyl group. The precursor of this acyl group was
prepared from C24 â-ketoester 47.27 Enantioselective
reduction28 of the keto group led to (R)-â-hydroxy ester
48 in high yield. The racemic compound had been
prepared previously by a similar approach.29 Compound
48 was saponified to provide the fatty acid building block,
(24) Kerekgyarto, J .; Szurmai, Z.; Liptak, A. Carbohydr. Res. 1993,
245, 65-80.
(25) Asselineau, J . Fortschr. Chem. Org. Naturst. 1991, 56, 1-85.
(26) Zaehringer, U.; Lindner, B.; Rietschel, T. Adv. Carbohydr.
Chem. Biochem. 1994, 50, 211-276.
(27) (a) Sta¨llberg-Stenhagen, S.; Stenhagen, E. Ark. Kemi, Mineral.
Geol. 1945, 19A1, 5-13; Chem. Abstr. 1947, 41, 3047b. (b) Sta¨llberg-
Stenhagen, S. Ark. Kemi, Mineral. Geol. 1946, 20A19, 5-22; Chem.
Abstr. 1947, 41, 4105d.
(28) Capozzi, G.; Roelens, S.; Talami, S. J . Org. Chem. 1993, 58,
7932-7936.
(29) Skogh, M. Acta Chem. Scand. 1952, 6, 809-817.
(30) Hatakeyama, S.; Mori, H.; Kitano, K.; Yamada, H.; Nishizawa,
M. Tetrahedron Lett. 1994, 35, 4367-4370.
2294 J . Org. Chem., Vol. 69, No. 7, 2004

Fully Synthetic C-Mycoside GPL
SCHEME 5
from 1.0 g of L-rhamnose monohydrate, 5.5 mmol) in absolute
CHCl3 (10 mL) was treated with 4-pentenol (1.15 mL, 11
mmol) and 2,6-lutidine (1.3 mL, 11 mmol). The solution was
stirred at rt for 2 d, diluted with CHCl3 (20 mL), and washed
with water, 2 N aq HCl, and satd aq NaHCO3. Drying over
MgSO4 was followed by coevaporation with toluene and CHCl3.
Chromatography using Hex/EtOAc 3:1 led to 7a as a colorless
crystallizing syrup (1.72 g, 87%). Recrystallization could be
promoted by solubilization in ether followed by addition of
hexane and cooling. Purification by simple crystallization
without prior chromatography led to lower yields. Compound
7a : mp 61-62 °C, recryst mp 64 °C; [R]25D +17 (c 2.0, CHCl3);
1H NMR (360 MHz, CDCl3) δ 5.72 (mc, 1 H), 5.33 (d, 1H, J 2.1
Hz), 5.15-4.85 (m, 4 H), 4.61 (dd, 1 H, J 2.1, 3.8 Hz), 3.50-
3.35 (m, 3 H), 2.04, 1.99 (2s, 2 × 3 H), 2.01, 1.68 (2 mc, 2 × 2
H), 1.66 (s, 3 H), 1.16 (d, 3 H); 13C NMR (90 MHz, CDCl3) δ
170.0, 169.7, 137.9, 124.1, 114.8, 97.1, 76.5, 70.7, 70.4, 69.1,
61.8, 30.0, 28.6, 24.7, 24.5, 20.7, 17.5.
1,2-O-[(S)-1-(4-P en ten yloxy)eth ylid en e]-3,4-d i-O-m eth -
yl-â-L-r h a m n op yr a n ose (7b). A solution of 7a (950 mg, 2.65
mmol) in 1,4-dioxane (25 mL) was treated with powdered
NaOH (1.15 g, 29 mmol) and stirred for 2 h at rt. MeI (830
µL, 13.7 mmol) was added, and the mixture was stirred
overnight. The excess methylating reagent was destroyed by
addition of MeOH (1 mL). After 2 h, the solvent was evapo-
rated and the residue taken up in CH2Cl2 and water. The
aqueous phase was extracted twice with CH2Cl2, and the
combined organic layers were washed with water and aq
Na2S2O3. Drying over MgSO4, evaporation of the solvent, and
debenzylation of the C-terminal benzyl ester of 56
without affecting the benzyl ethers was achieved by
hydrogenolysis with palladium on charcoal in slightly
amine alkaline medium. For the final coupling of the
resulting glycopeptidolipid 57 with glycopeptide 11, the
carbodiimide EDCI was used together with an excess
hydroxybenzotriazole (HOBt). The coupling reaction af-
forded the protected GPL 58 in 57% yield. Quinoline-
derived coupling reagents such as IIDQ were less satis-
factory as they led predominantely to carbamates instead
of the desired amide. Finally, debenzylation of 58 in
slightly acidic methanol furnished the target compound,
the complete GPL specific of M. avium serovar 4 (1).4b
Con clu sion
Starting from L-fucose, L-rhamnose, D-alanine, L-ala-
nine, D-phenylalanine, behenic acid (C22), and crotonic
acid, the specific GPL of M. avium serovar 4 was
synthesized in 62 steps by a convergent synthesis involv-
ing 18 steps in the longest sequence. This constitues the
first total synthesis of a complete “polar mycoside C”
GPL.
Exp er im en ta l Section
3,4-Di-O-acetyl-1,2-O-[(S)-1-(4-pen ten yloxy)eth yliden e]-
â-L-r h a m n op yr a n ose (7a ). A solution of 213 (crude product
J . Org. Chem, Vol. 69, No. 7, 2004 2295

Heidelberg and Martin
chromatography of the residue using Hex/EtOAc 3:1 gave pure
7b as a colorless syrup (650 mg, 81%). The chromatographic
purification may be avoided by using Me2SO4 (1.15 mL in two
additions, 12 mmol) instead of MeI as methylating agent to
give 7b (1.67 g from 2.15 g 7a (92%)): [R]25D +15 (c 1.9, CHCl3);
1H NMR (360 MHz, CDCl3) δ 5.80 (mc,1 H), 5.31 (bs, 1 H),
5.01, 4.95, 4.53 (3 mc, 3 H), 3.56, 3.54 (2s, 2 × 3 H), 3.53 (mc,
2 H), 3.37 (dd, 1 H, J 4.1, 9.1 Hz), 3.25 (dq, J 9.2, 3 × 6.1 Hz,
H-5), 3.10 (t, 1 H), 2.11 (mc, 2 H), 1.70 (s, 3 H), 1.65 (mc, 2 H),
1.30 (d, 3 H); 13C NMR (90 MHz, CDCl3) δ 138.1, 123.6, 114.8,
97.3, 81.3, 81.2, 76.1, 70.3, 61.8, 61.0, 57.7, 30.2, 28.8, 24.5,
17.8.
N-Ben zyloxyca r bon yl-D-a la n in yl-L-a la n in ol (9). A solu-
tion of 8 (5.0 g, 16 mmol) in MeOH (17 mL) and THF (17 mL)
was dropped into a freshly prepared solution of NaBH4 (3.4 g,
90 mmol) in aq MeOH (50 mL, 80%) at 0 °C during 20 min.
The reaction was stirred at rt overnight and then neutralized
with 2 N aq HCl. The salts were removed by filtration and
extracted with MeOH. The filtrate was evaporated to dryness,
and the residue was dried by coevaporation with CHCl3 before
taking up in CHCl3 and filtration. After concentration, the
CDCl3) δ 7.42 (d, 1 H, J 6.0 Hz), 4.79 (≈s, 1 H), 4.16, 4.02 (2
mc, 2 H), 3.64-3.37 (m, 5 H), 3.53, 3.49 (2 s, 2 × 3 H), 3.07 (t,
1 H, J 9.5 Hz), 1.34 (d, 3 H, J 6.8 Hz), 1.29 (d, 3 H, J 6.2 Hz),
1.19 (d, 3 H, J 6.7 Hz); 13C NMR (90 MHz, CDCl3) δ 99.4, 81.8,
81.3, 70.6, 67.8, 67.5, 60.8, 57.4, 50.7, 44.3, 21.6, 17.7.
4-P en ten yl 2,3-O-isop r op ylid en e-r-L-r h a m n op yr a n o-
sid e (12). A mixture of L-rhamnose monohydrate (1.5 g, 8.2
mmol) and p-toluenesulfonic acid monohydrate (20 mg, 105
µmol) was treated with 4-pentenol (12 mL) under nitrogen.
The mixture was heated to 95 °C for 1.5 d, and the solvent
was then removed under vacuum. The crude pentenyl rham-
noside was dissolved in CH2Cl2 (50 mL), and 2,2-dimethoxy-
propane (5 mL) was added. The solution was stirred at rt for
1 d (2 h are sufficient) and then washed with aq NaHCO3 and
dried over MgSO4. The solvent was evaporated, and residual
4-pentenol removed by coevaporation with toluene. Drying
under vacuum yielded almost pure 12 (2.1 g, 94%) as a yellow
syrup. Further purification by chromatography using Hex/
EtOAc 3-4:1 proved to be unnecessary: [R]23 -29 (c 2.3,
D
CHCl3); 1H NMR (360 MHz, CDCl3) δ 5.81, 5.03, 4.98 (3 mc, 3
H), 4.94 (∼s, 1 H, H-1), 4.14 (∼d, 1 H, J 5.8 Hz), 4.09 (mc, 1
H), 3.75-3.63, 3.48-3.37 (2 m, 2 × 2 H), 2.13, 1.69 (2 mc, 2 ×
CH2), 1.53, 1.36 (2 s, 2 × 3 H), 1.29 (d, 3 H, J 6.3 Hz); 13C
NMR (90 MHz, CDCl3) δ 137.9, 115.0, 109.5, 97.2, 78.3, 75. 9,
74.5, 67.0, 66.0, 30.3, 28.6, 27.9, 26.1, 17.5.
crude product was crystallized from toluene leading to com-
1
pound 9 (4.1 g, 90%): mp 134 °C; [R]21 +2 (c 2.0 CHCl3); H
D
NMR (360 MHz, CDCl3) δ 7.37-7.28 (m, 5 H), 6.57 (bs, 1 H),
5.72 (d, 1 H, J 7.0 Hz), 5.08, 5.06 (2 d, 2 H, J 12.3 Hz), 4.21
(dq, 1 H, J 6.4, 7.0 Hz), 4.04 (mc 1 H), 3.63 (dd, 1 H, J 3.0,
11.1 Hz), 3.43 (dd, 1 H, J 6.0, 11.1 Hz), 3.22 (bs, 1 H), 1.36 (d,
3 H), 1.12 (d, 3 H, J 6.4 Hz); 13C NMR (90 MHz, CDCl3) δ 128.4,
128.0, 127.8, 66.9, 65.4, 50.5, 47.2, 18.3, 16.4. Anal. Calcd for
4-P en ten yl 6-Deoxy-2,3-O-isop r op ylid en e-r-L-a r a bin o-
h exos-4-u lop yr a n osid e (13). To a solution of 12 (2.1 g, 7.7
mmol) in anhyd CH2Cl2 (90 mL) were added 4 Å molecular
sieves (5.0 g) and PCC (5.0 g, 23 mmol), and the mixture was
stirred at rt overnight. About 50 mL of CH2Cl2 was evaporated,
the residue was poured into ether (800 mL), and the chromium
salts were removed by filtration through a short column of
silica. Concentration of the filtrate led to 13 (1.85 g, 88%) as
a slightly yellow syrup: 1H NMR (360 MHz, CDCl3) δ 5.80,
5.03, 4.99 (3 mc, 3 H), 4.93 (s, 1 H), 4.43 (mc, 2 H), 4.25 (q, 1
H, J 6.8 Hz), 3.76, 3.53 (2 mc, 2 H), 2.13, 1.71 (2 mc, 2 × 2 H),
1.49, 1.37 (s, 2 × 3 H), 1.40 (d, 3 H, J 6.8 Hz); 13C NMR (90
MHz, CDCl3) δ 137.7, 115.2, 111.4, 97.0, 78.8, 76.0, 70.1, 67.9,
30.1, 28.4, 26.7, 25.5, 16.1.
C
14H18N2O4: C, 59.99; H, 7.19; N, 9.99. Found: C, 59.46; H,
7.07; N, 9.96.
(2S)-2-(N -Be n zyloxyca r b on yl-D-a la n in yla m in o)p r o-
pyl 2-O-Acetyl-3,4-di-O-m eth yl-r-L-r h am n opyr an oside (10).
Compounds 7b (350 mg, 1.2 mmol) and 9 (400 mg, 1.4 mmol)
were dissolved in anhyd CH2Cl2 (25 mL). NIS (300 mg, 1.3
mmol) followed by TMS triflate (500 µL) were added under a
nitrogen atmosphere, and the reaction was stirred for about
30 min at rt. The mixture was diluted with CH2Cl2 and washed
with aq Na2S2O3 and aq NaHCO3. After having been dried with
MgSO4, the organic solution was concentrated and the residue
purified by chromatography using CH2Cl2/acetone/MeOH 100:
4-P en ten yl 6-Deoxy-2,3-O-isop r op ylid en e-r-L-ta lop y-
r a n osid e (14). Compound 13 (2.45 g, 9.1 mmol) was dissolved
in ice-cold aq EtOH (95%, 40 mL) and treated with NaBH4
(170 mg, 4.5 mmol). After 30 min, the mixture was allowed to
warm to rt and stirred for a further 2 h. The salts were
removed by filtration, and the solution was concentrated to
dryness. The residue was dissolved in CH2Cl2 and washed with
a small amount of water. Drying over MgSO4 and concentra-
tion furnished 14 (2.3 g, 93%/74% based on L-rhamnose) as a
5:1-2 to give 10 (465 mg, 81%) as a glass-forming syrup: [R]21
D
1
-38 (c 1.0, CHCl3); H NMR (360 MHz, CDCl3) δ 7.38-7.29
(m, 5 H), 6.18 (d, 1 H, J 7.0 Hz), 5.54 (bs, 1 H), 5.22 (dd, 1 H,
J 1.6, 3.4 Hz), 5.13 (mc, 2 H), 4.68 (d, 1 H, J 1.6 Hz), 4.22, 4.18
(2 mc, 2 H), 3.63 (dd, 1 H, J 4.5, 10.0 Hz), 3.54 (s, 3 H), 3.52
(dq, 1 H, J 9.3, 4 × 6.2 Hz), 3.51 (dd, 1 H, J 3.4, 9.3 Hz), 3.35
(s, 3 H), 3.33 (dd, 1 H, J 4.3, 10.0 Hz), 3.06 (t, 1 H, J 9.3 Hz),
2.11 (s, 3 H), 1.38 (d, 3 H, J 7.0 Hz), 1.29 (d, 3 H, J 6.2 Hz),
1.18 (d, 3 H, J 6.1 Hz); 13C NMR (90 MHz, CDCl3) δ 171.5 (C),
170.5 (C), 156.4 (C), 136.2 (C), 128.6, 128.2, 128.1, 97.7 (1J CH
172 Hz, Rha-C1), 81.9, 79.6, 70.2 (CH2), 68.4, 67.8, 67.1 (CH2),
60.9, 57.5, 50.7, 44.8, 21.0, 18.3, 17.9, 17.6. Anal. Calcd for
clear colorless syrup: [R]23 -41 (c 2.1, CHCl3); 1H NMR (360
D
MHz, CDCl3) δ 5.81, 5.03, 4.98 (3 mc, 3 H), 5.01 (∼s, 1 H),
4.21 (dd, 1 H, J 6.4, 5.4 Hz), 4.03 (∼d, 1 H), 3.84 (∼q, 1 H, J
6.6 Hz), 3.72, 3.45 (2 mc, 2 H), 3.54 (∼dd, 1 H, J 5.4, 5.8 Hz),
2.31, 1.69 (2 mc, 2 × 2 H), 1.58, 1.38 (2 s, 2 × 3 H), 1.31 (d, 3
H, J 6.6 Hz); 13C NMR (90 MHz, CDCl3) δ 138.0, 114.9, 109.3,
97.5, 73.5, 73.1, 67.1, 67.0, 64.4, 30.3, 28.7, 25.9, 25.3, 16.7.
C
24H36N2O9: C, 58.05; H, 7.31; N, 5.64. Found: C, 57.77; H,
7.30; N, 5.60.
(2S)-2-(D-Ala n in yla m in o)p r op yl 3,4-Di-O-m et h yl-r-L-
r h a m n op yr a n osid e (11). Compound 10 (375 mg, 76 mmol)
was dissolved in anhyd MeOH (20 mL) and treated with
methanolic NaOMe (2 mL, 50 mM). The reaction was stirred
for several hours at rt until TLC indicated complete conversion.
Neutralization with Amberlite IR 120(H+) ion-exchange resin
was followed by filtration and concentration to dryness. The
obtained (2S)-2-(N-ben zyloxyca r bon yl-D-a la n in yla m in o)-
p r op yl 3,4-Di-O-m eth yl-r-L-r h a m n op yr a n osid e was ho-
mogeneous by NMR spectroscopy. It may be purified by
chromatography using CH2Cl2/acetone/MeOH 100:5:3-3.5.
The intermediate was dissolved in MeOH (70 mL), treated
with Pd(OH)2/C (20%, 50 mg) and hydrogenolyzed under 100
psi hydrogen overnight. The catalyst was removed by micro-
filtration and the solution concentrated. After drying under
vacuum, compound 11 (235 mg, 97%) was obtained as a
spectroscopically pure colorless syrup: 1H NMR (360 MHz,
4-P en ten yl 4-O-ben zyl-6-deoxy-r-L-talopyr an oside (16).
To a solution of 14 (5.35 g, 20 mmol) in 1,4-dioxane (50 mL)
were added powdered NaOH (2 g, 50 mmol) and BnBr (2.5
mL, 21 mmol), and the reaction was heated to 80 °C overnight.
More BnBr (0.5 mL, 4 mmol) was then added, and heating
was continued for 2 d. The solvent was then evaporated and
the residue taken up in CH2Cl2 and water. The organic layer
was separated, washed with brine, and dried over MgSO4.
Concentration afforded crude 15: 1H NMR (250 MHz, CDCl3)
δ 7.45-7.23 (m, 5 H), 5.80, 5.01, 4.96 (3 mc, 3 H), 4.90 (d, 1 H,
J 1.6 Hz), 4.85, 4.56 (2 d, 2 H, J 12.1 Hz), 4.41 (dd, 1 H, J 6.8,
4.6 Hz), 4.04 (dd, 1 H, J 1.6, 6.8 Hz), 3.88 (dq, 1 H, J 3.7, 3 ×
6.6 Hz), 3.70 (mc, 1 H), 3.61 (dd, 1 H, J 3.7, 4.6 Hz), 3.45 (mc,
1 H), 2.09, 1.66 (2 mc, 2 × 2 H), 1.57, 1.38 (2 s, 2 × 3 H), 1.21
(d, 3 H, J 6.6 Hz); 13C NMR (63 MHz, CDCl3) δ 138.0, 137.99,
128.5-127.6 (m), 114.8, 109.6, 97.6, 74.4, 74.0, 72.7, 72.1, 67.6,
67.0, 30.2, 28.7, 26.2, 25.4, 16.8; C21H30O5. Compound 15 was
2296 J . Org. Chem., Vol. 69, No. 7, 2004

Fully Synthetic C-Mycoside GPL
dissolved in 80% aq AcOH (50 mL), and the solution was
heated to 50 °C for about 1 h and then concentrated. Coevapo-
ration with toluene followed by chromatography using Hex/
EtOAc 5:1 gave pure 16 (3.5 g, 55%) and slightly contaminated
chromatography afforded 20 (1.35 g, 50% based on rhamnose
monohydrate) and isomer 14 (290 mg, 13% based on rhamnose
monohydrate). Compound 20: [R]25 -77 (c 1.7, CDCl3); 1H
D
NMR (360 MHz, CDCl3) δ 5.81, 5.01, 4.95 (3 mc, 3 H), 4.73 (d,
1 H, J 5.4 Hz), 4.49 (dd, 1 H, J 3.4, 7.4 Hz), 4.09 (dd, 1 H, J
7.4, 2.0 Hz), 3.81 (dq, 1 H, J 2.0, 3 × 6.5 Hz), 3.77, 3.46 (2 mc,
2 H), 3.68 (dd, 1 H, J 5.4, 3.4 Hz), 2.31 (bs, 1 H, OH), 2.11,
1.69 (2 mc, 2 × 2 H), 1.51, 1.35 (2 s, 2 × 3 H), 1.24 (d, 3 H, J
6.5 Hz); 13C NMR (90 MHz, CDCl3) δ 138.2, 114.8, 109.9, 100.5,
76.2, 73.5, 68.8, 67.4, 65.0, 30.3, 28.9, 26.0, 25.2, 15.9.
16 (750 mg, 12%, 67% in total): mp 53-55 °C; [R]20 -86 (c
D
1.2, CDCl3); 1H NMR (250 MHz, CDCl3) δ 7.45-7.28 (m, 5 H),
5.80, 5.01, 4.97 (3 mc, 3 H), 4.84 (bs, 1 H), 4.78, 4.71 (2 d, 2 H,
J 11.0 Hz), 3.89 (bq, 1 H, J 3 × 6.6 Hz), 3.84 (≈dd, 1 H, J 3.4,
10.3 Hz), 3.71-3.60 (m, 3 H), 3.41 (mc, 1 H), 3.36 (d, 1 H, J
11.7 Hz, 3-OH), 2.78 (d, 1 H, J 10.3 Hz, 2-OH), 2.11, 1.66 (2
mc, 2 × 2 H), 1.26 (d, 3 H, J 6.6 Hz, H-6); 13C NMR (63 MHz,
CDCl3) δ 138.0, 137.5, 128.6, 128.2, 128.1, 114.9, 100.9, 81.4,
76.7, 70.9, 67.1, 66.8, 65.8, 30.3, 28.6, 16.9.
4-P en ten yl 2-O-Ch lor oa cetyl-6-d eoxy-3,4-O-isop r op yl-
id en e-r-L-ta lop yr a n osid e (21). A solution of chloroacetic
anhydride (1.0 g, 5.8 mmol) in anhyd CH2Cl2 (25 mL) was
added dropwise to an ice-cold solution of 20 (1.1 g, 4.0 mmol)
and NEt3 (800 µL, 5.7 mmol) in anhyd CH2Cl2 (30 mL). Stirring
was continued overnight, allowing the mixture to warm to rt.
After dilution with CH2Cl2 the reaction mixture was washed
with 1 N aq HCl and satd aq NaHCO3. Drying with MgSO4,
concentration of the solution, and chromatography of the crude
product using Hex/EtOAc 10:1 gave 21 (1.2 g, 85%) as a
colorless syrup: [R]23D -100 (c 1.1, CDCl3); 1H NMR (250 MHz,
CDCl3) δ 5.80 (mc, 1 H), 5.06-4.92 (m, 2 H), 5.00 (dd, 1 H, J
6.4, 2.9 Hz), 4.85 (d, 1 H, J 6.4 Hz), 4.60 (dd, 1 H, J 2.9, 7.6
Hz), 4.19, 4.15 (2 d, 2 H, J 15.3 Hz), 4.15 (dd, 1 H, J 7.6, 1.7
Hz), 3.86 (dq, 1 H, J 1.7, 3 × 6.4 Hz), 3.75, 3.44 (2 mc, 2 H),
2.09, 1.65 (2 mc, 2 × 2 H), 1.51, 1.33 (2 s, 2 × 3 H), 1.23 (d, 3
H, J 6.4 Hz); 13C NMR (63 MHz, CDCl3) δ 167.2, 138.4, 115.2,
111.0, 97.7, 76.9, 73.2, 72.5, 67.6, 66.3, 41.3, 30.5, 29.1, 26.5,
25.7, 15.9. Anal. Calcd for C16H25ClO6: C, 55.09; H, 7.22; Cl,
10.16. Found: C, 53.91; H, 7.08; Cl, 11.24; these results are
consistent with the presence of 0.1 equiv of CH2Cl2 in the
product.
4-P en t en yl 3,4-Di-O-b en zyl-6-d eoxy-r-L-t a lop yr a n o-
sid e (17a ). A mixture of 16 (2.2 g, 6.8 mmol) and Bu2SnO (1.7
g, 6.8 mmol) was treated with benzene (150 mL) and heated
to reflux with continuous removal of water (Dean Stark) for 1
d. The resulting cloudy solution was concentrated to about 100
mL, and Bu4NBr (2.2 g, 6.8 mmol) and BnBr (1.8 mL, 15 mmol)
were added. Reflux was continued for 1 d, and the solvent was
then evaporated. Residual BnBr was removed by coevaporation
with water, and the residue was taken up in CH2Cl2 and
washed with water. After drying with MgSO4, the solvent was
evaporated and the crude mixture was separated by chroma-
tography using Hex/EtOAc 10:1 to afford 17a (1.15 g, 41%),
17b (1.06 g, 38%), and a mixture of both isomers (300 mg,
10%). Compound 17a : [R]20D -49 (c 2.0, CDCl3); 1H NMR (250
MHz, CDCl3) δ 7.53-7.21 (m, 10 H), 5.79 (mc, 1 H), 5.06-4.92
(m, 2 H), 5.00, 4.84, 4.63, 4.56 (4 d, 4 H), 4.87 (d, 1 H, J 1.5
Hz), 4.23 (d, 1 H, J 10.3 Hz, 2-OH), 3.97 (ddt, 1 H, 3J 10.3,
4
3.0, 1.5 Hz, J 1.5 Hz), 3.84 (bq, 1 H, J 3 × 6.6 Hz), 3.75 (∼t,
1 H, J 3.0 Hz), 3.66 (mc, 1 H, H-4), 3.63, 3.42 (2 mc, 2 H), 2.08,
1.64 (2 mc, 2 × 2 H), 1.21 (d, 3 H, J 6.6 Hz); 13C NMR (63
MHz, CDCl3) δ 138.2, 138.0, 137.7, 128.5, 128.4, 128. 3, 127.
9, 127.6, 127.6, 114.9, 101.5, 78.8, 75.5, 74.4, 69. 8, 68.1, 67.1,
66.4, 30.3, 28.6, 16.8.
D-Alloth r eon in e Ben zyl Ester Hyd r och lor id e (23). A
solution of 2219 (1.78 g, 7.6 mmol) in 1,4-dioxane (150 mL) was
treated with 0.5 N aq HCl (15 mL, 7.5 mmol) and Pt/C (180
mg, 5-10%). The mixture was hydrogenolyzed at normal
pressure until TLC indicated total conversion (2-7 d); the
atmosphere was replaced with fresh hydrogen several times.
After removal of the catalyst by membrane filtration, the
solution was concentrated to dryness and the residue was dried
under vacuum leaving crude 23. For purification the compound
was dissolved in MeOH (5 mL) and precipitated by addition
of ether (100 mL). After filtration and drying under vacuum,
4-P en ten yl 3,4-Di-O-ben zyl-2-O-ch lor oa cetyl-6-d eoxy-
r-L-ta lop yr a n osid e (18). A solution of chloroacetic anhydride
(790 mg, 4.6 mmol) in anhyd CH2Cl2 (5 mL) was added
dropwise to an ice-cold solution of 17a (1.2 g, 2.9 mmol) and
pyridine (1.8 mL, 22 mmol) in anhyd CH2Cl2 (15 mL). Stirring
was continued and the reaction was allowed to warm to rt
overnight. The diluted mixture was washed with 2 N aq HCl
and aq NaHCO3, dried over MgSO4, and concentrated, and the
crude product was purified by chromatography using Hex/
pure 23 (1.5 g, 81%) was obtained: mp 145-147 °C; [R]21 ∼0
D
(c 2.0, MeOH); 1H NMR (250 MHz, CD3OD) δ 7.45-7.36 (m, 5
H), 5.33, 5.28 (AB, 2 H, J 12.1 Hz), 4.26 (dq, 1 H, J 3.5, 3 ×
6.6 Hz), 4.11 (d, 1 H, J 3.5 Hz), 1.20 (d, 3 H, J 6.6 Hz); 13C
NMR (63 MHz, CD3OD) δ 168.3, 136.3, 129.8, 129.8, 129.7,
69.1, 66.5, 59.4, 18.5.
EtOAc 9:1 to give 18 (1.3 g, 91%): [R]18 -35 (c 1.25, CDCl3);
D
1H NMR (250 MHz, CDCl3) δ 7.45-7.23 (m, 10 H), 5.79 (mc, 1
3
4
H), 5.36 (∼dt, 1 H, J 1.5, 3.0 Hz, J 1.5 Hz), 5.01, 4.96 (2 mc,
2 H), 4.85 (∼bs, 1 H), 4.87, 4.66 (2 d, 2 H, J 11.5 Hz), 4.77,
4.52 (2 d, 2 H, J 11.7 Hz), 4.07, 3.95 (AB, 2 H, J 15.4 Hz), 3.88
(dq, 1 H, J 1, 3 × 6.6 Hz), 3.81 (∼t, 1 H, J 3.3 Hz), 3.64 (mc, 1
H), 3.55 (mc, 1 H), 3.41 (mc, 1 H), 2.09, 1.66 (2 mc, 2 × 2 H),
1.26 (d, 3 H, J 6.6 Hz); 13C NMR (63 MHz, CDCl3) δ 167.4,
138.8, 137.9, 137. 9, 128.4, 128.3, 128.1, 127.7, 127.6, 127.55,
115.0, 98.2, 75.9, 75.0, 74. 5, 71.1, 68. 9, 67.1, 66.9, 41.1, 30.2,
28.5, 16.7.
N-2,2,2-Tr ich lor oeth oxyca r bon yl-D-p h en yla la n in yl-D-
a lloth r eon in e Ben zyl Ester (25). A solution of 2420 (1.0 g,
2.9 mmol) and IIDQ (0.91 g, 3.0 mmol) in anhyd CH2Cl2 (50
mL) was stirred for a few minutes and then treated with 23
(700 mg, 2.85 mmol). After stirring overnight, the solution was
washed with aq HCl and then with aq NaHCO3, dried over
MgSO4, and concentrated. Chromatography of the residue
using Hex/EtOAc 2:1 gave 25 (1.2 g, 79%) as a syrup.
Alternatively, the product may be purified by crystallization
from toluene leading to solid 25 in 64% yield: mp 108-109
4-P en ten yl 6-Deoxy-3,4-O-isop r op ylid en e-r-L-ta lop y-
r a n osid e (20). Compound 14 (crude product from 1.5 g, 8.2
mmol, L-rhamnose monohydrate) was dissolved in aq HOAc
(50 mL, 90%), and the mixture was kept at 50 °C for 2 h. After
evaporation of the solvent and coevaporation of traces of AcOH
with toluene, pure 19 was obtained: 1H NMR (360 MHz,
CDCl3) δ 5.81, 5.01, 4.97 (3 mc, 3 H), 4.85 (∼s, 1 H), 3.91 (∼q,
1 H, J 3 × 6.4 Hz), 3.78 (mc, 2 H), 3.67, 3.67, 3.44 (3 mc, 3 H),
2.99 (bs, 3 H, OH), 2.11, 1.67 (2 mc, 2 × 2 H), 1.29 (d, 3 H, J
6.4 Hz); 13C NMR (90 MHz, CDCl3) δ 137.9, 114.4 (CH2), 100.4,
72.9, 70.6, 67.2 (CH2), 66.6, 65.9, 30.3 (CH2), 28.7 (CH2), 16.5;
°C; [R]23 -15 (c 1.1, CHCl3); 1H NMR (360 MHz, CDCl3) δ
D
7.39-7.17 (m, 10 H), 6.59 (d, 1 H, J 7.0 Hz, NH), 5.56 (d, 1 H,
J 7.3 Hz, NH), 5.17 (s, 2 H), 4.70 (mc, 2 H), 4.59 (dd, 1 H, J
3.2, 7.0 Hz), 4.47 (∼q, 1 H, J 7.3 Hz), 4.13 (mc, aThr-3), 3.09
(mc, 2 H), 1.05 (d, 3 H, J 7.5 Hz); 13C NMR (90 MHz, CDCl3)
δ 129.2-128.4, 127.3, 74.7 (CH2), 68.9 (CH2), 67.6, 58.5, 56.5,
38.4, 18.6. Anal. Calcd for C23H25Cl3N2O6: C, 51.94; H, 4.74;
N, 5.27; Cl, 20.00. Found: C, 52.21; H, 4.77; N, 5.21; Cl, 20.34.
C
11H20O5. A solution of the sample of 19 thus obtained and
N-(2,2,2-Tr ich lor oeth oxyca r bon yl)-D-p h en yla la n in yl-
[O-(3,4-d i-O-ben zyl-2-O-ch lor oa cetyl-r-L-ta lop yr a n osyl)-
D-a lloth r eon in e ben zyl ester ] (26). A solution of 18 (800
mg, 1.6 mmol) and 25 (850 mg, 1.6 mmol) in anhyd CH2Cl2
(50 mL) was treated with NIS (412 mg, 1.8 mmol). TMS triflate
HOTs‚H2O (20 mg, 0.1 mmol) in CH2Cl2 (50 mL) was treated
with 2,2-dimethoxypropane (5 mL). The solution was stirred
at rt for about 1 h and then washed with satd aq NaHCO3.
Drying with MgSO4 followed by concentration and flash
J . Org. Chem, Vol. 69, No. 7, 2004 2297

Heidelberg and Martin
(0.8 mL, 4.4 mmol) was added dropwise under an inert
atmosphere, and the reaction mixture was stirred for 15 min
at rt. The diluted reaction mixture was washed with aq
NaHCO3, aq Na2S2O,3 and again aq NaHCO3, dried over
MgSO4, and concentrated. Final purification by chromatogra-
phy using Hex/EtOAc 3:1 to 3:2 led to 26 (950 mg, 64%).
Besides 26, slightly impure 25 (300 mg, ∼30%) and 30 (180
CDCl3); 1H NMR (250 MHz, CDCl3) δ 7.42-7.13 (m, 20 H),
6.71 (d, 1 H, J 7.8 Hz, NH), 5.50 (d, 1 H, J 6.8 Hz, NH), 5.17
(mc, 1 H), 5.12 (mc, 2 H, J 12.2 Hz), 4.85 (bs, 1 H), 4.81 (d, 1
H), 4.75-4.57 (m, 5 H), 4.41 (d, 1 H), 4.36 (mc, 1 H), 4.05, 3.91
(AB, 2 H, J 15.4 Hz), 3.97 (dq, 1 H, J 3.2, 3 × 6.6 Hz), 3.71
(dq, 1 H, J 1, 3 × 6.6 Hz), 3.57 (t, 1 H, J 3.3 Hz), 3.42 (mc, 1
H), 3.08 (d, 2 H, J 7.1 Hz), 1.23, 1.16 (2 d, 2 × 3 H, J 6.6 Hz);
13C NMR (63 MHz, CDCl3) δ 169.9, 168.7, 167.3, 151.5, 138.6,
137.8, 135.8, 135.0, 129.3-127.2 (m), 97.1, 95.2, 75.5, 75.4,
74.60, 74.6, 74.3, 71.1, 69.2, 68.1, 67.4, 56.7, 56.5, 41.0, 38.3,
16.7, 16.6.
N-(2,2,2-Tr ich lor oeth oxyca r bon yl)-D-p h en yla la n in yl-
[O-(3,4-O-isop r op ylid en e-r-L-ta lop yr a n osyl)-D-a lloth r eo-
n in e ben zyl ester ] (29). A solution of 28 (365 mg, 0.45 mmol)
in lutidine (3.6 mL) and HOAc (1.2 mL) was treated with
hydrazinodithiocarbonate (HDTC, 4 mL of ethanolic solution,
∼80 mmol)31 and stirred at rt for 10 min. The reaction was
diluted with CH2Cl2 (15 mL), and 2 N aq HCl was added. The
mixture was stirred for a few minutes at rt before separating
the layers. The aqueous phase was extracted twice with CH2-
Cl2, and the combined organic phases were washed with aq
HCl and aq NaHCO3. After drying with MgSO4, the crude
product was purified by chromatography using Hex/EtOAc 3:2.
Compound 29 (235 mg, 71%) was obtained as a solidifying
mg, 9%) were also isolated. Compound 26: [R]20 -21 (c 1.1,
D
syrup: mp 56-67 °C; [R]19 -21 (c 1.3, CDCl3); 1H NMR (250
D
MHz, CDCl3) δ 7.43-7.10 (m, 10 H), 7.01 (d, 1 H, J 8.6 Hz,
NH), 5.60 (d, 1 H, J 7.8 Hz, NH), 5.18 (s, 2 H), 4.73, 4.63 (2 d,
2 H, J 12.0 Hz), 4.71 (dd, 1 H, J 8.6, 2.9 Hz), 4.63 (d, 1 H, J
6.6 Hz), 4.45 (dd, 1 H, J 3.0, 7.8 Hz), 4.44 (dt, 1 H, J 7.8, 2 ×
6.6 Hz), 3.99 (dd, 1 H, J 7.8, 1.7 Hz), 3.92 (dq, 1 H, J 2.9, 3 ×
6.5 Hz), 3,44 (mc, 2 H), 3.13 (dd, 1 H, J 13.9, 6.6 Hz), 3.06 (dd,
1 H, J 13,9, 6.6 Hz), 1.47, 1.33 (2 s, 2 × 3 H), 1.29 (d, 3 H, J
6.6 Hz), 1.16 (d, 3 H, J 6.5 Hz); 13C NMR (63 MHz, CDCl3) δ
169.8 (C), 168.8 (C), 153.9 (C), 135.9 (C), 135.4 (C), 129.5, 128.7,
128.6, 128.5, 127.1, 110.2 (C), 100.0, 95.3 (C), 76.4, 75.9, 74.6
(CH2), 73.6, 68.9, 67.1 (CH2), 66.2, 56.7, 56.3, 38.8 (CH2), 26.1,
25.0, 17.9, 15.8. Anal. Calcd for C32H39Cl3N2O10: C, 53.53; H,
5.47; N, 3.90; Cl, 14.81. Found: C, 53.31; H, 5.65; N, 3.77; Cl,
14.78.
N-(2,2,2-Tr ich lor oeth oxyca r bon yl)-D-p h en yla la n in yl-
[O-(3,4-d i-O-b en zyl-r-L-t a lop yr a n osyl)-D-a llot h r eon in e
ben zyl ester ] (27). Compound 26 (900 mg, 0.95 mmol) and
thiourea (250 mg, 3.3 mmol) were dissolved in a mixture of
pyridine (5 mL) and EtOH (5 mL), and the mixture was heated
to 60 °C for 3 h (TLC monitoring). After evaporation of the
solvents, the crude product was dissolved in CH2Cl2 and the
solution was washed with dilute aq HCl and aq NaHCO3. The
organic solution was dried with MgSO4 and concentrated, and
the residual product was purified by chromatography using
Hex/EtOAc 3:1 to 2:1 to give 27 (780 mg, 94%): mp 50-58 °C;
Meth yl 3-O-Ben zyl-2-O-m eth yl-1-th io-â-L-fu cop yr a n o-
sid e (40). To a solution of 3924 (2.37 g, 11 mmol) in benzene
(80 mL) was added Bu2SnO (3.61 g, 14.5 mmol), and the
mixture was refluxed with continuous removal of water (Dean
Stark) for 1 d. The solvent was then removed and the residue
dried under vacuum. DMF (60 mL) was added, and the
resulting suspension was treated with anhyd CsF (2.2 g, 14.5
mmol) and BnBr (2 mL, 17 mmol). The reaction mixture was
stirred at rt for 2 d, and the DMF was then evaporated. The
residue was distributed between EtOAc (100 mL) and 1 N aq
KF (60 mL). The aqueous phase was extracted with EtOAc
(50 mL), and the combined organic layers were washed with
water (60 mL) and dried over MgSO4. Chromatography of the
crude product using Hex/EtOAc 1:0 - 3:1 led to pure 40 (2.2
[R]17 -27 (c 1.0, CDCl3); 1H NMR (250 MHz, CDCl3) δ 7.44-
D
7.14 (m, 20 H), 6.76 (d, 1 H, J 8.6 Hz, NH), 5.50 (d, 1 H, J 7.8
Hz, NH), 5.11 (AB, 2 H, J 12.8 Hz), 4.95 (d, 1 H, J 12.0 Hz),
4.84 (bs, 1 H), 4.73 (d, 1 H, J 11.7 Hz), 4.74-4.56 (m, 4 H),
4.45 (d, 1 H, J 11.7 Hz), 4.39 (mc, 1 H), 4.26 (d, 1 H, J 10.3 Hz,
3
2-OH), 3.95 (dq, 1 H, J 3.2, 3 × 6.5 Hz), 3.80 (dddd, 1 H, J 1,
4
2.9, 10.3 Hz, J 1-1.5 Hz), 3.66 (bq, 1 H, J 3 × 6.6 Hz), 3.52
(∼bs, 1 H), 3.47 (t, 1 H, J 2.9 Hz), 3.11, 3.05 (ABX, 2 H, J
13.9, 6.6, 6.4 Hz), 1.21, 1.09 (2 d, 2 × 3 H, J 6.4 and 6.6 Hz);
13C NMR (63 MHz, CDCl3) δ 169.8, 168.9, 154.0, 138.1, 137.4,
135.8, 135.0, 129.3-127.2, 100.6, 95.2, 78.3, 75.5, 75.4, 74.5,
73.9, 69.7, 68.4, 67.4, 67.3, 56.8, 56.4, 38.3, 16.9, 16.8. Anal.
Calcd for C43H47Cl3N2O10: C, 60.18; H, 5.52; N, 3.26; Cl, 12.39.
Found: C, 59.67; H, 5.38; N, 3.26; Cl, 12.06.
g, 65%) as a slightly cloudy syrup: [R]23 +13 (c 1.2, CHCl3);
D
1H NMR (250 MHz, CDCl3) δ 7.45-7.28 (m, 5 H), 4.73 (mc, 2
H), 4.18 (d, 1 H, J 9.5 Hz), 3.79 (∼bt, 1 H, J 3.4, 2.7 Hz), 3.63
(s, 3 H), 3.53 (∼bq, 1 H, J 6.4 Hz), 3.46 (dd, 1 H, J 9.0, 3.4
Hz), 3.33 (∼t, 1 H, J 9 Hz), 2.29 (d, 1 H, J 2.7 Hz, OH), 2.22
(s, 3 H), 1.33 (d, 3 H, J 6.4 Hz); 13C NMR (63 MHz, CDCl3) δ
137.9, 128.5, 128.0, 127.8, 85.1, 82.6, 79.0, 74.1, 72.2, 69.6, 61.2,
16.6, 12.7. Anal. Calcd for C15H22O4S: C, 60.38; H, 7.43.
Found: C, 60.27; H, 7.30.
N-(2,2,2-Tr ich lor oeth oxyca r bon yl)-D-p h en yla la n in yl-
[O-(2-O-ch lor oa cetyl-3,4-O-isop r op ylid en e-r-L-ta lop yr a -
n osyl)-D-a lloth r eon in e ben zyl ester ] (28). A solution of 21
(100 mg, 0.29 mmol) and 25 (120 mg, 0.23 mmol) in anhyd
CH2Cl2 (9 mL) was treated with NIS (70 mg, 0.31 mmol) and
TMS triflate (140 µL, 0.77 mmol, dropwise) under inert
atmosphere. After 30 min, TLC (Hex/EtOAc 3:2) indicated
complete conversion. NEt3 (several drops) was added to
neutralize the acid, and the solution was diluted and washed
with aq Na2S2O3 and aq NaHCO3. Drying over MgSO4 was
followed by concentration and immediate chromatography
using Hex/EtOAc 4:1 to give pure 28 (125 mg, 70%) as a
Meth yl 3-O-Ben zyl-4-O-ch lor oacetyl-2-O-m eth yl-1-th io-
â-L-fu cop yr a n osid e (41). To a solution of 35 (2.24 g, 7.5
mmol) and pyridine (6 mL, 74 mmol) in anhyd CH2Cl2 (50 mL)
was added dropwise a solution of chloroacetic anhydride (2.59
g, 15 mmol) in anhyd CH2Cl2 at -15 °C. Stirring was continued
below 0 °C for 1 h, and the reaction was then worked up as
described for the preparation of 18 to give 41 (2.57 g, 91%):
[R]27D -2.5 (c 1.2, CDCl3); 1H NMR (250 MHz, CDCl3) δ 7.40-
7.28 (m, 5 H), 5.39 (bd, 1 H, J 3.5 Hz), 4.72, 4.55 (2 d, 2 H, J
11.4 Hz), 4.24 (d, 1 H, J 9.5 Hz), 4.19 (s, 2 H), 3.68 (dq, 1 H,
J 0.7, 3 × 6.4 Hz), 3.60 (s, 3 H), 3.54 (dd, 1 H, J 9.0, 3.5 Hz),
solidifying syrup: mp 60-75 °C; [R]23 -41 (c 0.8, CDCl3); 1H
D
NMR (250 MHz, CDCl3) δ 7.46-7.14 (m, 10 H), 6.97 (d, 1 H,
J 9.0 Hz, NH), 5.57 (d, 1 H, J 7.3 Hz, NH), 5.19, 5.15 (2 d, 2
H, J 12.5 Hz), 4.82 (dd, 1 H, J 6.7, 2.6 Hz), 4.74, 4.62 (2 d, 2
H, J 12.0 Hz), 4.70 (d, 1 H, J 6.7 Hz), 4.69 (dd, 1 H, J 2.8, 9.0
Hz), 4.51 (dd, 1 H, J 2.6, 7.6 Hz), 4.44 (mc, 1 H), 4.14, 4.10 (2
d, 2 H, J 15.0 Hz), 4.01 (dd, 1 H, J 7.6, 1.6 Hz), 3.85 (mc, 1 H),
3.37 (dq, 1 H, J 1.6, 3 × 6.6 Hz), 3.13 (dd, 1 H, J 13.9, 6.1 Hz),
3.06 (dd, 1 H, J 13.9, 6.9 Hz), 1.47, 1.30 (2 s, 2 × 3 H), 1.24 (d,
3 H, J 6.6 Hz), 1.14 (d, 3 H, J 6.2 Hz); 13C NMR (63 MHz,
CDCl3) δ 169.7, 168.6, 166.7, 153.9, 135.9, 135.3, 129.4, 128.7,
128.6. 127.1, 110.8, 97.4, 95.3, 77.2, 74.5, 72.5, 72.0, 67.2, 66.8,
56.6, 56.4, 40.7, 38.8, 26.1, 25.2, 18.1, 15.4. Anal. Calcd for
3.27 (t, 1 H, J 9 Hz), 2.24 (s, 3 H), 1.23 (d, 3 H, J 6.4 Hz); 13
C
NMR (63 MHz, CDCl3) δ 137.5, 128.4, 127.9, 127.8, 85.3, 80.5,
78.8, 72.6, 72.1, 71.9, 61.2, 40.8, 16.5, 12.9.
4-P en ten yl 2,4-Di-O-a cetyl-r-L-r h a m n op yr a n osid e (42).
4-Pentenyl R-L-rhamnopyranoside (crude product from 1.0 g
L-rhamnose monohydrate, 5.5 mmol, see 12) and TsOH‚H2O
(20 mg, 0.1 mmol) were dissolved in DMF (23 mL), and
C
34H40Cl4N2O11: C, 51.40; H, 5.07; N, 3.53; Cl, 17.85. Found:
(31) van Boeckel, C. A. A.; Beetz, T. Tetrahedron Lett. 1983, 24,
3775-3778.
C, 51.13; H, 5.27; N, 3.35; Cl, 17.88.
2298 J . Org. Chem., Vol. 69, No. 7, 2004

Fully Synthetic C-Mycoside GPL
trimethyl orthoacetate (1.5 mL, 12 mmol) was added. The
mixture was heated to 50 °C for 2 h and then cooled to rt.
NEt3 (2 mL) was added, and the solvent was evaporated. The
residue was taken up in pyridine (6 mL), and Ac2O (2.5 mL)
was added. After being stirred for 2 d at rt, MeOH (2.5 mL)
was added to destroy the excess anhydride. After 2 h, the
mixture was poured into 2 N aq HCl (70 mL), and the product
was extracted with CH2Cl2. After washing with aq HCl and
aq NaHCO3, the solution was dried over MgSO4 and concen-
trated and the crude 42 purified by chromatography using
4-P en ten yl 2,4-Di-O-a cetyl-3-O-[3-O-ben zyl-2-O-m eth -
yl-4-O-(2,3-di-O-acetyl-4-O-m eth yl-r-L-r h am n opyr an osyl)-
r-L-fu cop yr a n osyl]-r-L-r h a m n op yr a n osid e (45). To a so-
lution of 3423 (159 mg, 0.39 mmol) and 44 (180 mg, 0.32 mmol)
in anhyd CH2Cl2 (10 mL) was added powdered activated 4 Å
MS, and the mixture was stirred for a few minutes at rt under
argon. After the mixture was cooled in an acetone-dry ice
bath, TMSOTf (5 µL) was added, and the mixture was allowed
to warm inside the cooling bath overnight. The acid was
neutralized with NEt3 (50 µL), and the solids were filtered.
After concentration, the crude product was purified by chro-
matography using Hex/EtOAc 3:1 to give 45 (260 mg, quant):
Hex/EtOAc 3:1: yield 985 mg, 57% based on rhamnose
1
monohydrate; [R]23 -38 (c 1.5, CHCl3); H NMR (250 MHz,
D
[R]26 -100 (c 1.0, CHCl3); 13C NMR (63 MHz, CDCl3) δ 170.5
CDCl3) δ 5.80 (mc, 1 H), 5.09-4.96 (m, 3 H), 4.84 (∼t, 1 H, J
9.7 Hz), 4.77 (d, 1 H, J 1.2 Hz), 4.03 (ddd, 1 H, J 3.6, 9.0, 9.7
Hz), 3.81 (dq, 1 H, J 9.8, 3 × 6.4 Hz), 3.67, 3.43 (2 mc, 2 H),
2.20-2.08 (m, 2 H), 2.16, 2.13 (2 s, 2 × 3 H), 2.06 (d, 1 H, J
9.0 Hz, OH), 1.69 (mc, 2 H), 1.21 (d, 3 H, J 6.4 Hz); 13C NMR
(63 MHz, CDCl3) δ 171.5, 170.6, 137.9, 115.1, 97.1, 74.8, 72.9,
68.6, 67.3, 65.9, 30.2, 28.6, 21.1, 17.4. Anal. Calcd for
D
(C), 170.1 (C), 170.0 (C), 169.9 (C), 138.9 (C), 137.9, 128.2,
127.3, 127.2, 115.0 (CH2), 99.5 (J CH 169 Hz), 98.9 (J CH 165 Hz),
97.3 (J CH 175 Hz), 80.4, 78.5, 77.7, 77.2, 74.9, 72.5, 72.3 (CH2),
71.9, 70.8, 70.6, 67.8, 67.4 (CH2), 67.0, 66.5, 60.1, 59.2, 30.2
(CH2), 28.5 (CH2), 21.1, 21.0, 21.0, 20.9, 17.6, 17.4, 16.4; LRMS
(MALDI-TOF) 833.5 (M + Na), 849.5 (M + K).
C
15H24O7: C, 56.95; H, 7.65. Found: C, 56.75; H, 7.69.
4-P en ten yl 2,4-Di-O-ben zyl-3-O-[3-O-ben zyl-2-O-m eth -
yl-4-O-(2,3-di-O-ben zyl-4-O-m eth yl-r-L-r h am n opyr an osyl)-
r-L-fu cop yr a n osyl]-r-L-r h a m n op yr a n osid e (46). A solution
of 45 (500 mg, 0.62 mmol) in anhyd dioxane (5 mL) was treated
with powdered KOH (200 mg, 3.6 mmol) and heated to 40 °C
for 15 min. BnBr (0.32 mL, 2.7 mmol) was added, and the
reaction was heated to 80 °C overnight. TLC indicated that
saponification was complete but no benzylation occurred. More
dioxane (5 mL), powdered NaOH (1 g, 25 mmol), and BnBr (1
mL, 8.4 mmol) were then added, and the mixture was stirred
vigorously at 80 °C for 2 d. The solvent was evaporated and
excess BnBr removed by coevaporation with water. The crude
product was taken up in CH2Cl2, and the solution was washed
with water. After drying over MgSO4 and concentration, the
crude product was purified by chromatography using Hex/
EtOAc 5:1 to give 46 (410 mg, 66%) as an amorphous solid:
4-P en ten yl 2,4-Di-O-a cetyl-3-O-(3-O-ben zyl-4-O-ch lo-
r oa cet yl-2-O-m et h yl-r-L-fu cop yr a n osyl)-r-L-r h a m n op y-
r a n osid e (43). Compounds 41 (300 mg, 0.8 mmol) and 42 (235
mg, 0.74 mmol) were dissolved in anhyd CH2Cl2/Et2O (18 mL,
1:5), and 4 Å MS were added. The suspension was stirred at
rt under argon for a few minutes before the addition of IDCP
(iodonium biscollidine perchlorate, 800 mg, 1.7 mmol; smaller
amount led to incomplete reaction). After 30 min, TLC (CH2-
Cl2/acetone 20:1) showed complete conversion. The solids were
filtered and washed with CH2Cl2 (50 mL). The organic solution
was washed successively with aq Na2S2O3, 2 N aq HCl, and
aq NaHCO3 and then dried with MgSO4. The crude product
obtained after evaporation of the solvent was purified by
chromatography using Hex/EtOAc 5:1 to give 43 (290 mg,
1
60%): [R]23 -96 (c 1.1 CDCl3); H NMR (250 MHz, CDCl3) δ
D
[R]24 -97 (c 5.0, CDCl3); 1H NMR (250 MHz, CDCl3) δ 7.48-
7.38-7.27 (m, 5 H), 5.81 (mc, 1 H), 5.37 (bd, 1 H, J 3.3 Hz),
5.21-4.94 (m, 2 H), 5.14 (dd, 1 H, J 1.2, 3.4 Hz), 5.08 (dd≈t,
1 H, J 9.8, 10.0 Hz), 5.02 (d, 1 H, J 3.5 Hz), 4.70 (d, 1 H, J 1.2
Hz), 4.65, 4.50 (2 d, 2 H, J 11.3 Hz), 4.11 (bq, 1 H, J 3 × 6.6
Hz), 4.02 (dd, 1 H, J 3.4, 9.8 Hz), 3.82 (dd, 1 H, J 3.3, 10.0
Hz), 3.79, 3.67 (2 mc, 2 H), 3.47 (dd, 1 H, J 3.5, 10.0), 3.46 (s,
3 H), 3.42 (dq, 1 H, J 10.0, 3 × 6.4 Hz), 2.21-2.04 (m, 2 H),
1.69 (mc, 2 H), 1.20 (d, 3 H, J 6.4 Hz), 1.10 (d, 3 H, J 6.6 Hz);
13C NMR (63 MHz, CDCl3) δ 170.5, 169.9, 167.2, 137.9, 128.3,
127.9, 127.6, 115.1, 99.7, 97.2, 77.2, 75.8, 75.6, 72.9, 72.3, 71.9,
71.8, 67.4, 66.5, 65.2, 59.5, 40.8, 30.2, 28.5, 21.1, 20.9, 17.4,
16.0. Anal. Calcd for C31H43ClO12: C, 57.89; H, 6.74; Cl, 5.51.
Found: C, 57.81; H, 6.67; Cl, 5.39.
D
7.16 (m, 25 H), 5.80 (mc, 1 H), 5.14 (d, 1 H, J 4.4 Hz), 5.13 (d,
1 H, J 10.3 Hz), 5.01, 4.97 (2 mc, 2 H), 4.86-4.58 (m, 9 H),
4.54 (d, 1 H, J 11.0 Hz), 4.47 (d, 1 H, J 12.5 Hz), 4.09 (mc, 1
H), 3.98 (dd, 1 H, J 9.4, 2.8 Hz), 3.86 (∼bs, 1 H), 3.77-3.33
(m, 13 H), 3.55, 3.37 (2 s, 2 × 3 H), 3.30 (dd∼t, 1 H, J 9.5, 9.7
Hz), 2.08, 1.63 (2 mc, 2 × 2 H), 1.28 (d, 3 H, J 6.0 Hz), 1.07 (d,
3 H, J 6.0 Hz), 0.70 (d, 3 H, J 6.3 Hz); 13C NMR (63 MHz,
CDCl3) δ 139.1, 138.8, 138.7, 138.3, 138.2, 138.1, 128.3, 128.3,
128.1, 127.7, 127.5, 127.5, 127.4, 127.3, 127.2, 127.1, 114.8,
100.3, 99.6, 96.7, 82.5, 80.0, 79.5, 79.1, 78.1, 78.0, 77.9, 76.2,
74.7, 74.0, 72.8, 72.2, 71.7, 71.6, 68.4, 68.2, 66.9, 66.3, 60.8,
59.7, 30.3, 28.6, 17.9, 17.8, 16.4.
Meth yl (R)-3-Hyd r oxytetr a cosa n oa te (48). A solution of
4727 (4.1 g, 10 mmol) in hot anhyd MeOH (55 mL) under
nitrogen was transferred into a nitrogen flushed Parr ap-
paratus and treated with (R)-BINAP-ruthenium(p-cymene)
chloride (60 mg). The mixture was heated to 90 °C and
hydrogenated at 400 psi H2 pressure for 1 d. After being cooled
to rt, the suspension was treated with active charcoal and
heated to reflux for 5 min. The suspension was filtered hot
and slowly cooled to avoid rapid crystallization. Compound 48
(3.2 g, 78% not optimized) was obtained as a nearly colorless
solid: mp 73 °C; [R]25D -10 (c 2.7, CHCl3); 1H NMR (360 MHz,
CDCl3) δ 3.97 (mc, 1 H), 3.70 (s, 3 H), 2.48 (dd, 1 H, J 3.3, 16.3
Hz), 2.38 (dd, 1 H, J 8.9, 16.3 Hz), 1.60-1.35 (m, 2 H), 1.22
(m, 38 H), 0.85 (t, 3 H); 13C NMR (90 MHz, CDCl3) 173, 68.1,
50.6, 41.2, 36.6, 31.9, 29.7-29.0 (m), 25.5, 22.3, 14.1. Anal.
Calcd for C25H50O3: C, 75.32; H, 12.64. Found: C, 74.84; H,
12.23.
Meth yl (R)-3-Ben zyloxytetr a cosa n oa te (50). To a solu-
tion of 48 (1.25 g, 3.1 mmol) in anhyd CH2Cl2 (25 mL) was
added NEt3 (1 mL, 7.2 mmol) followed by TMSCl (0.8 mL, 6.3
mmol). The solution was stirred at rt under inert atmosphere
for a few hours until TLC (Hex/EtOAc 10:1) showed complete
conversion. After cooling to 0 °C, the mixture was washed with
ice-cold aq NaHCO3 and water. The solution was dried over
4-P en ten yl 2,4-d i-O-a cetyl-3-O-(3-O-ben zyl-2-O-m eth yl-
r-L-fu cop yr a n osyl)-r-L-r h a m n op yr a n osid e (44). A mixture
of 43 (266 mg, 0.41 mmol) and thiourea (103 mg, 1.35 mmol)
was treated with pyridine (1.5 mL) and anhyd EtOH (1.5 mL)
and heated to 60 °C for 1.5 h until TLC (Hex/EtOAc 3:2)
indicated complete conversion. The solvents were evaporated,
and the residue was distributed between CH2Cl2 and dilute
aq HCl. The aqueous layer was extracted with CH2Cl2, and
the combined organic phases were washed with 2 N aq HCl
and sat aq NaHCO3. Drying over MgSO4 was followed by
evaporation of the solvent. Chromatography of the crude
product using Hex/EtOAc 3:1 gave 44 (205 mg, 87%): [R]24
D
-69 (c 1.2 CDCl3); 1H NMR (250 MHz, CDCl3) δ 7.42-7.28
(m, 5 H), 5.81 (mc, 1 H), 5.15 (dd, 1 H, J 1.7, 3.4 Hz), 5.08
(dd≈t, 1 H, J 9.8, 10.0 Hz), 5.00-4.95 (m, 2 H), 4.99 (d, 1 H,
J 3.7 Hz), 4.71 (d, 1 H, J 1.7 Hz), 4.71, 4.63 (2 d, 2 H, J 11.8
Hz), 4.02 (dd, 1 H, J 3.4, 9.8 Hz), 3.94 (∼bq, 1 H, J ≈ 6 Hz),
3.86-3.61 (m, 3 H), 3.69, 3.45 (2 mc, 2 H), 3.58 (dd, 1 H, J 3.7,
9.8 Hz), 3.46 (s, 3 H), 2.34 (bs, 1 H, OH), 2.14 (mc, 2 H), 2.12,
2.08 (2 s, 2 × 3 H), 1.70 (mc, 2 H), 1.22, 1.19 (2 d, 2 × 3 H, J
6.4, 6.0 Hz); 13C NMR (63 MHz, CDCl3) δ 170.5 (C), 170.0 (C),
138.2 (C), 137.9, 128.5, 127.8, 127.8, 115.1 (CH2), 99.5, 97.2,
77.4, 77.2, 75.5, 72.4, 72.3 (CH2), 71.9, 70.0, 67.4 (CH2), 66.4,
66.1, 59.2, 30.2 (CH2), 28.5 (CH2), 21.1, 20.9, 17.4, 16.0.
J . Org. Chem, Vol. 69, No. 7, 2004 2299

Heidelberg and Martin
MgSO4 and concentrated to give the O-TMS derivative of 48
(1.40 g, 95%): 1H NMR (250 MHz, CDCl3) δ 4.11 (mc, 1 H),
3.68 (s, 3 H), 2.44 (d, 2 H, J 6.4 Hz), 1.52-1.39 (m, 2 H), 1.25
(mc, 38 H), 0.88 (t, 3 H, J 6.7 Hz), 0.10 (s, 9 H); C28H58O3Si.
This compound and benzaldehyde (370 µL, 3.6 mmol) were
dissolved in anhyd CH2Cl2 (30 mL) and the solution was cooled
to 0 °C. TMS triflate (54 µL, 0.3 mmol) was added and the
mixture was stirred at 0 °C for 1 h before the addition of
triethylsilane (0.5 mL, 3 mmol). The reaction mixture was
stirred at rt for 2-4 h and then diluted with ether (50 mL)
and washed with satd aq NaHCO3 (100 mL) and water (50
mL). After being dried over MgSO4, the organic solution was
concentrated. Crystallization of the crude product from MeOH
led to pure 50 (1.02 g, 70%): [R]20D -3 (c 1.1, CDCl3); 1H NMR
(250 MHz, CDCl3) δ 7.33-7.20 (m, 5 H), 4.54 (s, 2 H), 3.88
(mc, 1 H), 3.67 (s, 3 H), 2.61 (dd, 1 H, J 14.7, 7.2 Hz), 2.47 (dd,
1 H, J 14.7, 5.1 Hz), 1.70-1.52 (m, 2 H), 1.25 (mc, 38 H), 0.88
(t, 3 H); 13C NMR (63 MHz, CDCl3) δ 172.7, 138.9, 128.7, 128.2,
127.9, 76.5, 71.9, 52.0, 40.2, 34.8, 32.3, 30.1-29.8 (m), 25.6,
23.1, 14.5; LRMS (IS) 489.5 (M + H).
(R)-3-Ben zyloxytetr a cosa n oic Acid (51). Compound 50
(1.0 g, 2.0 mmol) was dissolved in hot EtOH (50 mL) and
treated with 2 N aq NaOH (2.2 mL, 2.2 mmol). The reaction
was stirred for 2-4 h and occasionally warmed to dissolve the
precipitating solid. When TLC (Hex/EtOAc 5:1) showed com-
plete conversion, the solvent was evaporated and the residue
distributed between CH2Cl2 (70 mL) and 2 N aq HCl (10 mL).
Concentration of the dried organic solution (MgSO4) was
followed by crystallization of the product from anhyd EtOH
(10 mL) to give pure 51 (277 mg) and slightly contaminated
51 (120 mg, total yield 41%): [R]24D -5 (c 1.6, CDCl3); 1H NMR
(250 MHz, CDCl3) δ 7.77 (mc, 5 H), 4.57 (s, 2 H), 3.87 (dddd≈p,
1 H, J 6.8, 5.4, 2 × 6 Hz), 2.63 (dd, 1 H, J 15.7, 6.8 Hz), 2.55
(dd, 1 H, J 15.7, 5.4), 1.75-1.47 (m, 2 H), 1.26 (mc, 38 H), 0.88
(t, 3 H, J 6.6 Hz); 13C NMR (63 MHz, CDCl3) δ 175.9, 137.9,
128.3, 127.8, 127.7, 75.7, 71.5, 39.2, 33.8, 31.8, 29.6-29.3 (m),
25.0, 22.6, 14.0.
(d, 3 H, J 6.4 Hz); 13C NMR (63 MHz, CDCl3) δ 169.9 (C), 168.8
(C), 154.0 (C), 139.0 (2×, C), 138.9 (C), 138.6 (C), 138.4 (C),
138.2 (C), 138.1 (C), 135.9 (C), 135.0 (C), 129.3-127.1 (m),
100.2 (1J CH 170 Hz), 98.9 (1J CH 169 Hz), 98.2 (1J CH 168 Hz),
97.4 (1J CH 175 Hz), 95.2 (C), 82.5, 80.0, 79.5, 78.3, 77.9, 77.8
(2×), 77.1, 76.0, 74.6 (CH2), 74.5 (CH2), 74.1, 73.0 (CH2), 72.8
(CH2), 72.2 (CH2), 71.8, 71.6 (CH2), 71.5 (CH2), 71.4 (CH2), 68.4,
68.3, 68.3, 67.2 (CH2), 66.3, 60.8, 59.4, 56.8, 56.4, 38.5 (CH2),
18.0, 17.8, 16.7, 16.6, 16.3; LRMS (IS) 1798 (M + Na), 1776
(M + H), 1526, 1280, 1185, 917, 882, 859, 623, 533; LRMS
(MALDI-TOF) 1796, 1798 (M + Na).
N-(3R)-3-Ben zyloxyt et r a cosa n oyl-D-p h en yla la n in yl-
O-{3,4-d i-O-b en zyl-2-O-(2,4-d i-O-b en zyl-3-O-[3-O-b en z-
yl-2-O-m eth yl-4-O-(2,3-di-O-ben zyl-4-O-m eth yl-r-L-r h am n o-
p yr a n osyl)-r-L-fu cop yr a n osyl]-r-L-r h a m n op yr a n osyl)-
r-L-t a lop yr a n osyl}-D-a llot h r eon in e Ben zyl E st er (56).
Compound 54 (72 mg, 41 µmol) was dissolved in THF (2 mL),
and activated zinc powder (100 mg) was added followed by 1
M aq KH2PO4 (170 µL). The reaction was stirred for 5 h at rt.
Because the reaction appeared to be still incomplete, more zinc
and dihydrogenophosphate (same amounts as before) were
added, and stirring was continued overnight. The solids were
then removed by filtration and washed with THF and EtOH.
The combined filtrates were concentrated, and the residual
product was dissolved in CH2Cl2. The solution was washed
with aq NaHCO3, dried over MgSO4, and concentrated to give
the intermediate amine 55 (55 mg, 85%). This amine was
dissolved in anhyd CH2Cl2 (2 mL), and NEt3 (10 µL, 72 µmol)
and a solution of 52 (25 mg, 49 µmol) in anhyd CH2Cl2 (2.5
mL) were added. The reaction mixture was stirred at rt for 2
d and then concentrated and the residue purified by chroma-
tography using Hex/EtOAc 5:2 to give pure 56 (42 mg, 50%):
[R]22 -60 (c 1.0, CHCl3); 13C NMR (63 MHz, CDCl3) δ 171.3,
D
170.8, 169.2, 139.2, 139.1, 138.9, 138.6, 138.4, 138.2 (2×),
137.9, 136.5, 135.2, 129.2-126.9, 100.2, 98.8, 97.6, 97.4, 82.5,
80.0, 79.4, 78.3, 77.9, 77.8, 77.2, 76.1, 76.0, 74.7, 74.6, 74.1,
73.1, 72.9, 72.7, 72.2, 71.8, 71.6, 71.4, 71.3, 71.1, 68.4, 68.2,
68.0, 66.2 (2 C), 60.8, 59.3, 56.9, 54.8, 40.7, 37.8, 33.3, 31.9,
29.7, 29.3, 25.2, 22.7, 18.0, 17.8, 16.8, 16.3, 15.9, 14.1; LRMS
(IS) 2094.5 (M + K), 2079.5 (M + Na), 2057 (M + H); LRMS
(MALDI-TOF) 2080.8, 2079.8, 2078.8 (M + Na).
(R)-3-Ben zyloxytetr a cosa n oyl Ch lor id e (52). Compound
51 (52 mg, 110 µmol) was dissolved in benzene (2 mL) by
warming to 40 °C, and oxalyl chloride (70 µL, 0.84 mmol) was
added. The reaction was stirred at 40 °C overnight. After
evaporation of the solvent and excess reagent, the product was
dried under vacuum to give nearly NMR pure 52 (54 mg):
[R]24D -5 (c 1, CH2Cl2); 1H NMR (250 MHz, CDCl3) δ 7.33 (mc,
5 H), 4.56 (s, 2 H), 3.96 (mc, 1 H), 3.12 (dd, 1 H, J 16.1, 7.8
Hz), 3.01 (dd, 1 H, J 16.1, 4.6 Hz), 1.71-1.45 (m, 2 H), 1.41-
1.21 (m, 38 H), 0.89 (t, 3 H, J 6.5 Hz).
(2S )-2-[N -(3R )-3-Be n zyloxyt e t r a cosa n oyl-D-p h e n yl-
alan in yl-O-{3,4-di-O-ben zyl-2-O-(2,4-di-O-ben zyl-3-O-[3-O-
benzyl-2-O-methyl-4-O-(2,3-di-O-benzyl-4-O-methyl-r-L-rham-
n op yr a n osyl)-r-L-fu cop yr a n osyl]-r-L-r h a m n op yr a n osyl)-
r-L-talopyr an osyl}-D-alloth r eon in yl-D-alan in ylam in o]pr o-
p yl 3,4-d i-O-m eth yl-r-L-r h a m n op yr a n osid e (58). Com-
pound 56 (41 mg, 20 µmol) was dissolved in MeOH/EtOAc (10
mL, 1:1), and NEt3 (500 µL) and Pd(OH)2/C (20%, 23 mg) were
added. The mixture was hydrogenated at rt and 1 atm for
about 5 h. Removal of the catalyst followed by concentration
led to 57 (41 mg, quant.). This compound was dissolved in
anhyd CH2Cl2 (2.5 mL). Compound 11 (10 mg, 31 µmol),
hydroxybenzotriazole hydrate (12 mg, 89 µmol), and after a
few minutes, EDCI (10 mg, 52 µmol) were added. The reaction
was stirred for 2 d at rt, diluted with CH2Cl2, and washed with
dilute aq HCl and satd aq NaHCO3. After drying over MgSO4
and concentration of the solution, the crude product was
purified by chromatography using CH2Cl2/acetone/MeOH 40:
2:1 to give 58 (26 mg, 57%): [R]22D -70 (c 1.0, CHCl3); 13C NMR
(63 MHz, CDCl3) δ 172.7, 171.9, 171.2, 168.6, 139.0, 138.9,
138.8, 138.7, 138.5, 138.3, 138.3, 138.3, 137.7, 129.0-127.1,
100.2, 99.9, 99.0, 97.2 96.3, 82.5, 81.9, 80.9, 79.9, 79.5, 78.4,
77.9 (2×), 77.8, 77.0, 76.0, 75.95, 74.9, 74.6, 74.1, 73.2, 72.8,
72.6, 72.3, 71.7, 71.5, 71.2, 70.7, 69.1, 68.5, 68.3, 67.7, 67.5,
66.3, 60.9, 60.8, 59.4, 57.3 (CH3), 57.3, 55.8, 49.1, 45.2, 40.5,
37.2, 33.0, 31.9, 29.7, 29.3, 25.3, 22.7, 18.0, 17.8 (2×), 17.5,
17.4, 16.40, 16.36, 15.5, 14.1; LRMS (IS) 2269.5 multiplet (M
+ H); LRMS (MALDI-TOF) 2292 multiplet (M + Na); HRMS
(FAB) calcd for C133H182N4O27Na 2290.2895, found 2290.2938.
N-2,2,2-Tr ich lor oet h oxyca r b on yl-D-p h en yla la n in yl-
O-{3,4-d i-O-b en zyl-2-O-(2,4-d i-O-b en zyl-3-O-[3-O-b en z-
yl-2-O-m eth yl-4-O-(2,3-di-O-ben zyl-4-O-m eth yl-r-L-r h am n o-
pyr an osyl)-r-L-fu copyr an osyl]-r-L-r h am n opyr an osyl)-r-L-
ta lop yr a n osyl}-D-a lloth r eon in e Ben zyl Ester (54). A solu-
tion of 46 (80 mg, 80 µmol/228 mg, 227 µmol) and 27 (65 mg,
76 µmol/186 mg, 217 µmol) in anhyd CH2Cl2/Et2O (1:5, 6 mL/
15 mL) was stirred with activated 4 Å MS (400 mg/1.0 g). IDCP
(200 mg, 0.43 mmol/558 mg, 1.2 mmol) was added, and the
reaction mixture was stirred at rt and with protection from
light under argon overnight. The solids were removed by
filtration, and the filtrate was diluted with CH2Cl2 and washed
with aq Na2S2O3, dilute aq HCl, and satd aq NaHCO3. After
being dried over MgSO4, the solution was concentrated and
the crude product purified by chromatography using Hex/
EtOAc 3:1 to give 54 (74 mg, 55%/230 mg, 60%). Beside
contaminated 46, a sample of pure 27 could be recovered
(second reaction: 35 mg, 19%). Compound 54: [R]23 -68 (c
D
1.0,CHCl3); 1H NMR (250 MHz, CDCl3) δ 7.53-7.05 (m, 45
H), 6.68 (d, 1 H, J 8.3 Hz, NH), 5.64 (d, 1 H, J 7.8 Hz, NH),
5.20 (d≈bs, 1 H, H-1), 5.18-5.04 (m, 3 H), 5.00 (d, 1 H, J 3.7
Hz), 4.84 (d, 1 H, J 1.7 Hz), 4.80-4.40 (m, e 19 H), 4.23 (d, 1
H, J 12.5 Hz), 4.12-3.89 (m, 3 H), 3.85-3.21 (m, e 13 H),
3.56, 3.32 (2 s, 2 × 3 H), 1.29 (d, 3 H, J 6.8 Hz), 1.23 (d, 3 H,
J 6.9 Hz), 1.19 (d, 3 H, J 6.6 Hz), 1.08 (d, 3 H, J 6.4 Hz), 0.55
(2S)-2-[N-(3R)-3-Hyd r oxytetr a cosa n oyl-D-p h en yla la n i-
n yl-O-{2-O-(3-O-[2-O-m et h yl-4-O-(4-O-m et h yl-r-L-r h a m -
2300 J . Org. Chem., Vol. 69, No. 7, 2004

Fully Synthetic C-Mycoside GPL
n op yr a n osyl)-r-L-fu cop yr a n osyl]-r-L-r h a m n op yr a n osyl)-
r-L-t a lop yr a n osyl}-D-a llot h r eon in yl-D-a la n in yla m in o]-
p r op yl 3,4-Di-O-m eth yl-r-L-r h a m n op yr a n osid e (1). A so-
lution of 58 (25 mg, 11 µmol) in methanol (15 mL) was treated
with concentrated acetic acid (150 µL) and Pd(OH)2/C (20%,
20 mg) and hydrogenolyzed at rt under normal pressure H2
for 1 d. The catalyst was removed by membrane filtration and
washed with methanol, and the solution was concentrated,
coevaporated with methanol, and dried under vacuum to give
1 (17 mg, quant): [R]24D -81 (c 1.0, MeOH); 13C NMR (63 MHz,
CD3OD, DEPT) δ 138.4, 130.2, 129.5, 127.8, 104.3, 103.9, 101.8,
99.6, 97.7, 84.2, 83.1, 82.8, 82.3, 80.1, 79.4, 79.3, 74.0, 72.9,
72.4, 72.3, 71.8, 71.3, 71.0, 70.0, 69.7, 69.5, 69.0, 68.7, 68.3,
68.0, 67.2, 61.1, 61.0, 58.5, 57.3, 59.1, 56.4, 50.6, 46.5, 44.6,
38.3, 38.2, 33.1, 30.8, 30.5, 26.6, 23.7, 18.9, 18.2, 18.0 (2×),
17.6, 17.0 (2×), 15.4, 14.5; LRMS (IS) 1570.0, 1571.0, 1572.0
(M + Na), 1565.0, 1566.0, 1567.0 (M + NH4), 1548.0, 1549.0,
1550.0 (M + H); HRMS (FAB) calcd for C77H134N4O27Na
1569.9133, found 1569.9145.
Ack n ow led gm en t. Support of this work by Labo-
ratoires OM S.A. (now OM-PHARMA), Meyrin, Swit-
zerland, and experimental assistance by Sophie Front
are gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Experimental pro-
cedures and analytical data for compounds 3a ,b, 4-6, 8, 9,
10 (alternative synthesis), deacetylated 10, 13 (alternative
synthesis), 17b, 20 (alternative synthesis), 24, 30-38, 49, and
53. This material is available free of charge via the Internet
at http://pubs.acs.org.
J O030304E
J . Org. Chem, Vol. 69, No. 7, 2004 2301