Synthesis and biological evaluation of sialylmimetics as rotavirus inhibitors

Article abstract of DOI:10.1021/jm0100887

Rotaviruses cause severe gastroenteritis in infants and are estimated to be responsible for over 600 000 deaths annually, primarily in developing countries. The development of potential inhibitors of this virus is therefore of great interest, particularly since the safety and efficacy of rotaviral vaccines has recently been questioned. This study describes the synthesis of a variety of compounds that can be considered as mimetics of N-acetylneuraminic acid thioglycosides and the subsequent in vitro biological evaluation of these sialylmimetics as inhibitors of rotaviral infection. Our results show that readily accessible carbohydrate-based compounds have the potential to act as inhibitors of rotaviral replication in vitro, presumably through inhibition of the rotaviral adhesion process.

Full text of DOI:10.1021/jm0100887

3292
J . Med. Chem. 2001, 44, 3292-3301
Syn th esis a n d Biologica l Eva lu a tion of Sia lylm im etics a s Rota vir u s In h ibitor s
Ashmath Fazli,† Susan J . Bradley,† Milton J . Kiefel,†,§ Clare J olly,‡ Ian H. Holmes,‡ and Mark von Itzstein*,†,§
Centre for Biomolecular Science and Drug Discovery, Griffith University (Gold Coast Campus),
PMB 50 Gold Coast Mail Centre, Queensland 9726, Australia, Department of Medicinal Chemistry, Monash University
(Parkville Campus), 381 Royal Pde, Parkville, Victoria 3052, Australia, and Department of Microbiology and Immunology,
University of Melbourne, Parkville, Victoria 3010, Australia
Received February 27, 2001
Rotaviruses cause severe gastroenteritis in infants and are estimated to be responsible for
over 600 000 deaths annually, primarily in developing countries. The development of potential
inhibitors of this virus is therefore of great interest, particularly since the safety and efficacy
of rotaviral vaccines has recently been questioned. This study describes the synthesis of a variety
of compounds that can be considered as mimetics of N-acetylneuraminic acid thioglycosides
and the subsequent in vitro biological evaluation of these sialylmimetics as inhibitors of rotaviral
infection. Our results show that readily accessible carbohydrate-based compounds have the
potential to act as inhibitors of rotaviral replication in vitro, presumably through inhibition of
the rotaviral adhesion process.
In tr od u ction
strains.16 Early work implicated glycoproteins as the
epitope recognized by rotavirus,17,18 although more
recent findings suggest that glycolipids are the more
likely recognition site.19,20 Investigations into the pos-
sible components of these glycoconjugate-based epitopes
resulted in the general consensus that animal strains
of rotavirus require sialylated glycoconjugates for
infection,5,18,20-24 although human strains appear to be
independent of sialic acids.18,22,25 However, it has also
been suggested that many animal strains do not require
host cell surface sialic acids for infectivity.25-27 The
assessment of sialic acid dependence or independence
is usually determined by pretreatment of cells with a
sialidase.18,25 To further add to the conjecture regarding
the requirement (or not) of sialic acids in the rotavirus
recognition and binding process, it has recently been
shown that human strains of rotavirus bind to ganglio-
side GM1 on the host cell surface.20
Rotaviruses are recognized as the single most impor-
tant cause of severe gastroenteritis in infants1 and are
estimated to be responsible for over 600 000 deaths
annually, primarily in developing countries.2 Rota-
viruses are highly host cell specific and infect mature
enterocytes in the mid and upper villous epithelium of
the small intestine.1 The rotavirus virion is composed
of three concentric layers of proteins surrounding a
genome of 11 segments of double-stranded RNA.1 The
outermost layer of the virion is composed of two
proteins, VP4 and VP7, which have been implicated in
the initial interaction between the virus and the host
cell.1,3-8 VP4 forms dimeric spikes that protrude from
the virion surface, with the base of these spikes inter-
acting with VP7.9,10 While VP4 has been identified as
the protein capable of haemagglutination, the precise
role of VP7 has not been completely defined although
it has been proposed that it modulates the functions of
VP411,12 and interacts with cell surface molecules after
initial attachment.4 It has also been established that
VP4 is associated with the virulence of rotavirus.13 Both
VP4 and VP7 have been shown to independently elicit
neutralizing antibodies, confer serotype specificity, and
induce protective immunity.14,15
Studies into mutations in VP4, specifically at residues
150 (Gly to Glu) and 187 (Lys to Arg), have shown that
the infectivity is altered from sialic acid dependent to
independent, although the variants still recognize sialic
acids.29 In an attempt to characterize the biochemical
nature of the rotavirus cellular recognition site, Guer-
rero et al. have recently investigated the susceptibility
of MA104 cells to infection by rotavirus.30 The conclusion
drawn from this study was that the epitope for rotavirus
binding is likely to be a complex of several components
including gangliosides, N-linked glycoproteins, and
other proteins such as integrins.30 The suggested in-
volvement of integrins in rotavirus infection is further
supported by earlier observations which identified in-
tegrin binding motifs within VP4 and VP7.4 The finding
that galactose specific lectins appear to show the most
inhibitory activity at blocking rotavirus infection of
MA104 cells suggests that galactose is involved in the
binding of rotavirus to the host cell.31 This latter work
also clearly showed that different strains of rotavirus
can have quite different recognition site specificities,
even within the group dependent on sialic acids.31 In
The cellular recognition site for rotavirus is not as
clearly defined as the roles of VP4 and VP7. Several
reports have described efforts directed toward gaining
a better understanding of the nature of the site for
rotavirus binding.16-30 A recent study shows that bind-
ing and entry of rotavirus is a complex process, with
the existence of multiple cell-surface interactions, some
of which are common between human and animal
* Address correspondence to Professor Mark von Itzstein, Centre
for Biomolecular Science and Drug Discovery, Griffith University (Gold
Coast Campus), PMB 50 Gold Coast Mail Centre, Queensland 9726,
Australia. Tel: +617 5552 7025. Fax: +617 5552 8098. E-mail:
m.vonitzstein@mailbox.gu.edu.au.
† Monash University.
§ Griffith University.
‡ University of Melbourne.
10.1021/jm0100887 CCC: $20.00 © 2001 American Chemical Society
Published on Web 08/11/2001

Sialylmimetics as Rotavirus Inhibitors
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20 3293
addition, it has been suggested that rotavirus initially
interacts with a sialic acid-containing cellular recogni-
tion site prior to interacting with a second determinant
which is independent of sialic acids.16,22,31 Recent evi-
dence tends to support the conclusion that sialic acids
are highly likely to be involved in the recognition process
by most strains of rotavirus.11,20,32 The consensus at this
point appears to be that strains of rotavirus sensitive
to sialidase treatment bind to gangliosides containing
terminal sialic acid residues, while rotavirus strains
insensitive to sialidase treatment recognize internal
sialic acids (like that found in GM1 which are resistant
to the action of some sialidases).20,32
accessible through synthesis.41-46 Sialylmimetics also
have the advantage of being more readily tailored to
have improved pharmacological properties, which is an
important issue in drug development. Some excellent
examples of the success of sialylmimetics include work
directed toward the development of mimetics of sialyl
Lewis x (4) as inhibitors of E-selectin.41-43 Of the many
examples reported, the sialylmimetic 5, in which the
entire sialic acid moiety has been replaced by a car-
boxylate group with an appended hydrophobic moiety,
exemplifies the potential advantages of employing
sialylmimetics since it shows higher affinity for E-
selectin than sialyl Lewis x itself.41
The involvement of sialic acids in the rotaviral adhe-
sion process has prompted several investigations into
the development of potential inhibitors based upon sialic
acid glycosides which may mimic elements of the
natural cellular recognition site(s).33-38 In vitro studies
have shown that the use of naturally derived substances
such as human milk lactadherin,33 sialyloligosaccha-
rides from egg yolk,34 and glycophorin A18,22 resulted
in a reduction in rotavirus infectivity. Inhibition of
rotavirus infection has also been achieved using exo-
genous GM1 and the sialylphospholipid 1.35 We have
20
Other examples of sialylmimetics include the influ-
enza virus sialidase inhibitor 6,47 which can be consid-
ered as a mimetic of Neu5Ac2en (7) and is based upon
the potent influenza virus sialidase inhibitor Relenza
(8).48 We have also been interested in the development
of Neu5Ac2en based sialylmimetics49,50 and have re-
ported the synthesis and sialidase inhibitory activity of
9.49
reported the synthesis and rotavirus inhibitory activity
of N-acetylneuraminic acid thioglycosides of the general
structure 2.36 We found that the partially O-acetylated
thiosialosides (e.g., 3) showed improved inhibitory activ-
ity compared to the corresponding non-O-acetylated
thiosialoside toward a bovine rotavirus strain (NCDV).36
This result is consistent with the earlier findings of
Willoughby and Yolken when investigating inhibition
of a simian strain of rotavirus (SA11),37 although their
results suggest that multiply O-acetylated N-acetyl-
neuraminic acid derivatives may have been responsible
for the inhibition.
Despite considerable investigations into the use of
N-acylneuraminic acid glycosides as potential inhibitors
of rotavirus, no chemotherapeutic agent has so far been
developed. The development of N-acylneuraminic acid
glycosides as potential inhibitors is complicated by the
complexity of chemistry surrounding N-acylneuraminic
acid manipulations and glycosidations.39,40 Several work-
ers have addressed this issue in other areas of sialic acid
biology and chemistry by using mimetics of sialic acid.
These sialylmimetics retain the structural features
essential for interaction with a particular protein but
are structurally simpler and consequently more readily
Our interest in the development of novel sialyl-
mimetics as potential inhibitors of sialic acid-recogniz-
ing proteins prompted us to investigate mimetics of
thiosialosides such as 2 as potential inhibitors of ro-
tavirus. This study describes our efforts toward the
synthesis of mimetics of thiosialosides and their evalu-
ation as inhibitors of rotavirus infection.

3294 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20
Fazli et al.
Sch em e 1. Retrosynthetic Approach toward
Sch em e 2a
Sialylmimetics
a
Reagents and conditions: (a) PhCHO, HCO2H, 2 h, rt; (b)
Ac2O, pyridine, 16 h, rt, 83%; (c) 90% aq TFA, 2 h, 0 °C, 74%; (d)
TsCl, pyridine, 2.5 h, 0 °C, 81%; (e) KSAc (5 equiv), acetone, 56
°C, 48 h, 74%.
worth remembering that 5 molar equiv of potassium
thioacetate is used during the thioacetylation reaction.
Our initial attempts at coupling between the thiol-
acetyl derivative 14 and methyl 2-bromopropionate
utilized Et2NH53 mediated coupling. Unfortunately, this
coupling was very slow with modest yields of ∼50% for
the desired product after 2 days at 40 °C.51 However,
hydrazinium acetate mediated coupling54 between the
C-6 thiolacetyl derivatives 13, 14, and 15 and methyl
2-bromopropionate afforded the sialylmimetics 18, 19,
and 20, respectively, in high yield.
Resu lts a n d Discu ssion
(i) Syn th esis of Sia lylm im etics. Our target com-
pounds for mimetics of R(2,6)-linked thiosialosides such
as 2 can be represented by the general structure 10
(Scheme 1). As can be seen, sialylmimetics of the general
structure 10 contain a carboxylate group in the same
relative position as the sialic acid carboxylate group in
thiosialosides such as 2. In addition, we wished to
explore not only the effect of varying the R group R to
the carboxylate moiety, in order to investigate the effects
of hydrophobicity and steric bulk, but also the nature
of the carbohydrate unit. From a retrosynthetic view-
point it was envisaged that two distinct approaches
toward sialylmimetics such as 10 could be employed.
We have described elsewhere our preliminary efforts
toward the synthesis of compounds of the general
structure 10,51 and have shown that route-b offers the
most flexible and efficient access, particularly since
many of the proposed acceptors 11 are commercially
available.
The synthesis of sialylmimetics of the general struc-
ture 10 relies upon ready access to the corresponding
C-6 thiolacetyl derivatives 12. Such compounds can
readily be obtained from the corresponding 6-O-tosyl
derivatives via displacement with potassium thio-
acetate.51,52 In this way the thiolacetyl derivatives 13
and 14, corresponding to glucose and galactose, respec-
tively, were obtained in high yield. The requisite C-6′
thiolacetyl lactoside derivative 15 was obtained via the
sequence shown in Scheme 2. 4′,6′-O-Benzylidenation
of methyl â-D-lactoside followed by acetylation gave the
4′,6′-protected lactoside 16, which was debenzylidenated
(90% aqueous TFA) and treated with p-toluenesulfonyl
chloride to give 17. Subsequent exposure of 17 to
potassium thioacetate (5 equiv) afforded the desired C-6′
thiolacetyl derivative 15. Interestingly, the C-4′ hy-
droxyl group in 17 is O-acetylated during the course of
the thiolacetylation reaction, as indicated by the pres-
1
ence of six O-acetyl signals in the H NMR spectrum of
1
15. In addition, the H NMR spectrum of 15 contains a
In a similar manner, the sialylmimetics 21-26 were
prepared by coupling between the C-6 thiolacetyl de-
rivatives and the appropriate R-bromo ester. Thus far
we had only introduced hydrophobic groups (i.e., R )
Me, Et, or Ph) into our sialylmimetics. To investigate
the effect of a hydrophilic group, we wanted to introduce
a hydroxyl functionality in “R”. We chose to use R-bromo-
one proton doublet at δ 5.37 (J ) 3.0 Hz) which is
characteristic, both in terms of chemical shift and
coupling constant, of the H-4 proton of the galactose ring
of lactosides when the galactose C-4 hydroxyl is acety-
lated. At this stage we are yet to determine the source
of the acetyl group on the C-4′ hydroxyl, although it is

Sialylmimetics as Rotavirus Inhibitors
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20 3295
Ta ble 1. Inhibition of Rotavirus by Sialylmimeticsa
a
Results are expressed as the concentration of compound (mM) at which 50% infection of control infected monolayers occurred (IC50).
Results published in ref 36.
b
γ-butyrolactone for coupling with our C-6 thiolacetyl
derivatives, since we knew that hydroxide mediated
deprotection of the product from coupling would result
in opening of the lactone to give a butyro alcohol.
Accordingly, hydrazinium acetate mediated coupling
between the C-6 thiolacetyl derivatives 13 and 14 and
R-bromo-γ-butyrolactone gave the sialylmimetics 27
(86% yield) and 28 (79% yield), respectively.
With a series of protected sialylmimetics in hand our
attention turned toward deprotection and subsequent
biological evaluation. Accordingly, each of the sialylmi-
metics 18-28 was exposed to dilute sodium hydroxide.
It has been suggested that highly acidic compounds can
produce unreliable results in the rotavirus neutraliza-
tion assay.55 In order to eliminate the possibility of
spurious results, after acidification during workup (to
pH ∼5), each product was dissolved in water and the
pH adjusted to 7.3 with sodium hydroxide solution to
ensure each compound was present as its sodium salt.
In this way, the sialylmimetics 29-39 were obtained
in good yield after HPLC purification.
(ii) Biologica l Eva lu a tion of Sia lylm im etics a s
In h ibitor s of Rota vir a l In fection . The synthesized
sialylmimetics were evaluated as potential inhibitors of
rotaviral infection using a standard in vitro neutraliza-
tion assay36 as detailed in the Experimental Section.
Briefly, this method involves the preincubation of the
sialylmimetic to be analyzed with a rotavirus strain
(either bovine NCDV or human Wa) prior to incubation
on MA104 cells. After incubation, virus neutralization
was determined using indirect immunofluorescent stain-
ing. The results obtained (Table 1) are expressed as the
concentration of compound at which 50% infection of
control infected monolayers occurred (IC50). It is clear
from the results shown in Table 1 that the glucose- and
galactose-based sialylmimetics appear to have no in-
hibitory activity toward either Wa (human) or NCDV
(bovine) strains of rotavirus. While this result was
somewhat disappointing, since rotavirus binds to cell
surface glycoconjugates it is perhaps not unexpected
that monosaccharides would not be recognized by the
viral adhesion protein and hence would not inhibit
rotaviral adhesion or infection. Consistent with this
hypothesis are the results obtained with the lactose-
based sialylmimetics. As can be seen (Table 1), each of
the three lactose-based sialylmimetics, 31, 34, and 37,
show inhibition of rotavirus infection. Significantly, the
“methyl” and “ethyl” lactose-based sialylmimetics, 31
and 34, respectively, show inhibition of the Wa (human)
strain of rotavirus. Although the degree of inhibition is
only moderate, to the best of our knowledge this
represents the first report of relatively simple carbohy-
drate derivatives exhibiting inhibition of a human strain
of rotavirus.
While it is not appropriate to draw too many conclu-
sions from the data presented here (Table 1), it could

3296 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20
Fazli et al.
Meth yl 2,3-Di-O-a cetyl-4,6-O-ben zylid en e-â-D-ga la cto-
pyr an osyl-(1,4)-2,3,6-tr i-O-acetyl-â-D-glu copyr an oside (16).
Benzaldehyde (30 mL) was added to a solution of methyl â-D-
galactopyranosyl-(1,4)-â-D-glucopyranoside (5.0 g, 14 mmol) in
HCO2H (30 mL), and the solution was stirred for 2 h at room
temperature under N2 before being concentrated under re-
duced pressure. The residue was chromatographed through a
short column (10 × 4 cm) of silica (EtOAc:MeOH, 3:1, Rf 0.4)
to give partially purified methyl 4,6-O-benzylidene-â-D-galac-
topyranosyl-(1,4)-â-D-glucopyranoside. Pyridine (40 mL) and
Ac2O (20 mL) were added, and the mixture was stirred for 16
be speculated that the “phenyl” lactose-based sialyl-
mimetic 37 is too sterically demanding (or too hydro-
phobic) for the Wa (human) strain of rotavirus. The level
of inhibition of 37 against the Wa (human) strain is
diminished with respect to the “methyl” and “ethyl”
lactose-based sialylmimetics 31 and 34, respectively. It
is also interesting to note that the “ethyl” lactose-based
sialylmimetic 34 shows a level of inhibition of the NCDV
(bovine) strain comparable to the thiosialoside 2. On the
basis of our present findings, it appears that the
minimum determinant for recognition by rotavirus is a
disaccharide unit possessing a negative charge.
h
at room temperature before being concentrated under
reduced pressure. Column chromatography (EtOAc:hexane,
2:1, Rf 0.4) gave 16 (7.6 g, 83%) which was crystallized from
EtOAc/hexane to give colorless needles: 1H NMR (CDCl3) δ
2.02, 2.05, 2.10 (15H, 3 × s, 5 × AcO), 3.47 (3H, s, OMe), 3.48-
3.51 (1H, m, GalH-5), 3.58-3.63 (1H, m, GlcH-5), 3.79 (1H,
dd, J 4,5 ) J 4,3 ) 9.4 Hz, GlcH-4), 4.02 (1H, dd, J 6,6′ 12.4, J 6,5
1.4 Hz, GlcH-6), 4.13 (1H, dd, J 6,6′ 12.0, J 6,5 5.0 Hz, GalH-6),
4.29 (1H, dd, J 6′,6 12.4, J 6′,5 1.2 Hz, GlcH-6′), 4.32 (1H, d, J 4,3
3.7 Hz, GalH-4), 4.39 (1H, d, J 1,2 7.9 Hz, GalH-1), 4.47 (1H, d,
J 1,2 7.9 Hz, GlcH-1), 4.51 (1H, dd, J 6′,6 12.0, J 6′,5 1.9 Hz, GalH-
6′), 4.87 (1H, dd, J 3,2 10.2, J 3,4 3.7 Hz, GalH-3), 4.90 (1H, dd,
J 2,3 9.4, J 2,1 7.9 Hz, GlcH-2), 5.21 (1H, dd, J 3,4 ) J 3,2 ) 9.4 Hz,
GlcH-3), 5.25 (1H, dd, J 2,3 10.3, J 2,1 7.9 Hz, GalH-2), 5.46 (1H,
s, PhCH), 7.33-7.41 (3H, m, Ph), 7.43-7.48 (2H, m, Ph); 13C
NMR (75.5 MHz, CDCl3) δ 20.8, 20.9, 21.0 (OC(O)Me), 57.1
(OMe), 62.4 (GlcC-6), 68.8 (GalC-6), 66.8, 69.5, 71.9, 72.4, 72.9,
73.3, 73.5 (GalC-2, GalC-3, GalC-4, GalC-5, GlcC-2, GlcC-3,
GlcC-5), 76.3 (GlcC-4), 101.3 (PhCH), 101.6, 101.9 (GalC-1,
GlcC-1), 126.8, 128.5, 129.4 (Ph), 137.9 (ipso Ph), 169.1, 169.9,
170.4, 170.6, 170.9 (OC(O)Me).
Exp er im en ta l Section
Gen er a l. Infrared spectra were recorded on a Hitachi 270-
30 infrared spectrometer as KBr disks. 1H and 13C spectra were
recorded using a Bru¨ker DRX-300 spectrometer unless indi-
cated otherwise. Chemical shifts are given in ppm relative to
the solvent used (CDCl3: 7.26 for 1H; 77.0 for 13C) or relative
to external Me4Si for D2O spectra. Assignments indicated with
an asterisk (*) correspond to those resonances clearly due to
the other diastereomer where such mixtures exist. Two-
dimensional DQF-COSY and HMQC experiments were re-
corded in order to assist with spectral assignment. Typically,
the following parameters were used: DQF-COSY - 16 scans,
512 slices, relaxation delay 2.0s; 1H-13C HMQC - 48 scans,
256 slices, relaxation delay 2.5s. ESI mass spectra were
obtained using a Micromass Platform II electrospray spec-
trometer. Reactions were monitored by TLC (Merck silica gel
plates GF254, cat. no. 1.05554), and products were generally
purified by flash chromatography using Merck silica gel 60
(0.040-0.063 mm, cat. no. 1.09385). Microanalyses were
performed at the Department of Chemistry, University of
Queensland, Australia. Methyl â-D-glucopyranoside and meth-
yl â-D-galactopyranoside were purchased from Sigma-Aldrich.
Methyl â-D-lactoside was prepared by treating hepta-O-acetyl-
R-lactosylbromide with sodium methoxide. All solvents were
distilled prior to use or were of analytical grade.
Meth yl 2,3-Di-O-a cetyl-â-D-ga la ctopyr a n osyl-(1,4)-2,3,6-
tr i-O-a cetyl-â-D-glu cop yr a n osid e. To a solution of 16 (6.0
g, 9.2 mmol) in CH2Cl2 (100 mL) at 0 °C under N2 was added
TFA (90% aqueous, 10 mL), and the solution was stirred for 2
h at 0 °C. The mixture was diluted with CH2Cl2 (100 mL),
washed with H2O (100 mL), saturated aqueous NaHCO3 (100
mL), and H2O (2 × 100 mL), dried (Na2SO4), and concentrated.
Column chromatography (EtOAc:hexane, 10:1, Rf 0.3) gave the
title compound (3.8 g, 74%) as an amorphous mass: IR 3495
1. Syn th esis of Th iola cetyl Der iva tives 13, 14, a n d 15.
Meth yl 2,3,4-Tr i-O-a cetyl-6-O-p-tolu en esu lfon yl-â-D-glu -
cop yr a n osid e. To a solution of methyl â-D-glucopyranoside
(1.0 g, 5.1 mmol) in pyridine (20 mL) at 0 °C under N2 was
added p-TsCl (1.1 g, 5.5 mmol). After the mixture was stirred
for 2.5 h, MeOH (2 mL) was added and the solution concen-
trated in vacuo. The residue was chromatographed through a
short column (10 × 2 cm) of silica (EtOAc:MeOH, 8:1, Rf 0.4)
to give partially purified methyl 6-O-p-toluenesulfonyl-â-D-
glucopyrandoside. Pyridine (10 mL) and Ac2O (5 mL) were
added, and the mixture was stirred for 16 h at room temper-
ature before being concentrated under reduced pressure.
Column chromatography (EtOAc:hexane, 1:2, Rf 0.3) gave
methyl 2,3,4-tri-O-acetyl-6-O-p-toluenesulfonyl-â-D-glucopy-
ranoside (2.1 g, 87%) as an amorphous mass: IR 2800, 1760,
1
(br), 1752, 1432, 1370, 1160, 1048 cm-1; H NMR (CDCl3) δ
2.03 (6H), 2.06 (6H), 2.10 (3H) (15H, 3 × s, 5 × AcO), 2.67
(2H, brs, OH), 3.46 (3H, s, OMe), 3.54 (1H, t, J 5,6/6′ 5.2 Hz,
GalH-5), 3.60-3.65 (1H, m, GlcH-5), 3.78-3.91 (4H, m, GlcH-
4, GlcH-6, GalH-6/6′), 4.10 (1H, d, J 4,3 2.9 Hz, GalH-4), 4.38
(1H, d, J 1,2 7.8 Hz, GlcH-1), 4.47-4.52 (1H, m, GlcH-6′), 4.48
(1H, d, J 1,2 7.8 Hz, GalH-1), 4.86 (1H, dd, J 3,2 10.2, J 3,4 2.9 Hz,
GalH-3), 4.88 (1H, dd, J 2,3 10.2, J 2,1 7.8 Hz, GlcH-2), 5.15-
5.24 (2H, m, GlcH-3, GalH-2); 13C NMR (75.5 MHz, CDCl3) δ
20.7, 20.8, 20.9, 21.0 (OC(O)Me), 57.0 (OMe), 61.9, 62.4 (GlcC-
6, GalC-6), 67.6, 69.9, 71.8, 72.8, 73.5, 73.8, 74.7, 76.6 (GlcC-
2, GlcC-3, GlcC-4, GlcC-5, GalC-2, GalC-3, GalC-4, GalC-5),
101.6, 101.9 (GlcC-1, GalC-1), 169.7, 169.9, 170.5, 170.7, 170.9
(OC(O)Me); ESIMS 589 (M + Na, 100%), 547 (37), 414 (48).
1
1380, 1250, 1050 cm-1; H NMR (CDCl3) δ 1.97, 1.99, 2.02 (3
Meth yl 2,3-Di-O-a cetyl-6-O-p-tolu en esu lfon yl-â-D-ga -
la ctop yr a n osyl-(1,4)-2,3,6-tr i-O-a cetyl-â-D-glu cop yr a n o-
sid e (17). To a solution of methyl 2,3-di-O-acetyl-â-D-galac-
topyranosyl-(1,4)-2,3,6-tri-O-acetyl-â-D-glucopyranoside (3.0 g,
5.3 mmol) in pyridine (40 mL) at 0 °C under N2 was added
p-toluenesulfonyl chloride (1.5 g, 7.9 mmol). After the mixture
was stirred for 2.5 h at 0 °C, MeOH (2 mL) was added and
the solution was concentrated in vacuo. Column chromatog-
raphy (EtOAc:hexane, 3:2, Rf 0.3) gave 17 (3.1 g, 81%) as an
× 3H, 3 × s, 3 × AcO), 2.45 (3H, s, ArMe); 3.43 (3H, s, OMe);
3.72-3.78 (1H, m, H-5), 4.05 (1H, t, J 4,3 ) J 4,5 ) 9.3 Hz, H-4),
4.06-4.12 (2H, m, H-6/6′), 4.37 (1H, d, J 1,2 7.8 Hz, H-1), 4.90
(1H, dd, J 2,3 10.2, J 2,1 7.8 Hz, H-2), 5.16 (1H, dd, J 3,2 10.2, J 3,4
9.3 Hz, H-3), 7.34 (2H, d, ArH), 7.77 (2H, d, ArH); ESIMS 492
(M + NH4, 100%), 443 (30).
The following was prepared in a similar manner:
Met h yl 2,3,4-Tr i-O-a cet yl-6-O-p -t olu en esu lfon yl-â-D-
ga la ctop yr a n osid e in 82% yield (chromatography EtOAc:
hexane, 2:3, Rf 0.3) as an amorphous mass: IR 2800, 1760,
amorphous mass: IR 3500, 2800, 1760, 1390, 1250, 1050 cm-1
;
1H NMR (CDCl3) δ 1.93, 2.02, 2.04, 2.06, 2.16 (5 × 3H, 5 × s,
5 × AcO), 2.46 (3H, s, ArMe), 3.47 (3H, s, OMe), 3.57-3.63
(1H, m, GlcH-5), 3.69-3.80 (2H, m, GlcH-4, GalH-5), 4.04 (1H,
d, J 4,3 3.0 Hz, GalH-4), 4.05-4.16 (3H, m, GlcH-6/6′, GalH-6),
4.26 (1H, dd, J 6′,6 10.4, J 6′,5 6.3 Hz, GalH-6′), 4.38 (1H, d, J 1,2
7.8 Hz, GlcH-1), 4.45 (1H, d, J 1,2 7.8 Hz, GalH-1), 4.86 (1H,
dd, J 2,3 9.6, J 2,1 7.8 Hz, GlcH-2), 4.90 (1H, dd, J 3,2 9.9, J 3,4 3.0
Hz, GalH-3), 5.10 (1H, dd, J 2,3 9.9, J 2,1 7.8 Hz, GalH-2), 5.16
(1H, t, J 3,4 ) J 3,2 ) 9.6 Hz, GlcH-3), 7.39 (2H, d, ArH), 7.81
1
1390, 1250, 1050 cm-1; H NMR (CDCl3) δ 1.96, 2.03, 2.04 (3
× 3H, 3 × s, 3 × AcO), 2.45 (3H, s, ArMe), 3.48 (3H, s, OMe),
3.93 (1H, t, J 5,6/6′ 6.3 Hz, H-5), 4.02 (1H, dd, J 6,6′ 9.9, J 6,5 6.3,
H-6), 4.14 (1H, dd, J 6′,6 9.9, J 6′,5 6.3, H-6′), 4.36 (1H, d, J 1,2 8.1
Hz, H-1), 4.98 (1H, dd, J 3,2 10.2, J 3,4 3.3 Hz, H-3), 5.14 (1H,
dd, J 2,3 10.2, J 2,1 8.1 Hz, H-2), 5.35 (1H, d, J 4,3 3.3 Hz, H-4),
7.34 (2H, d, ArH), 7.75 (2H, d, ArH); ESIMS 492 (M + NH4,
100%).

Sialylmimetics as Rotavirus Inhibitors
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20 3297
(2H, m, ArH), assignments confirmed by COSY; 13C NMR (75.5
MHz, CDCl3) δ 20.5, 20.6, 20.7 (OC(O)Me), 21.5 (ArMe), 56.8
(OMe), 61.9, 66.9 (GlcC-6, GalC-6), 66.3, 69.3, 71.5, 72.1, 72.5,
72.6, 73.0, 75.8 (GlcC-2, GlcC-3, GlcC-4, GlcC-5, GalC-2, GalC-
3, GalC-4, GalC-5), 100.6, 101.3 (GlcC-1, GalC-1), 127.6, 130.0
(ArC-2/3), 132.5 (ArC-4), 145.2 (ArC-1), 169.2, 169.5, 169.9,
170.0, 170.4 (OC(O)Me); ESIMS 738 (M + NH4, 100%).
Meth yl 2,3,4-Tr i-O-a cetyl-6-th iola cetyl-â-D-glu cop yr a -
n osid e (13). To a solution of methyl 2,3,4-tri-O-acetyl-6-O-p-
toluenesulfonyl-â-D-glucopyranoside (2.5 g, 5.3 mmol) in dry
acetone (100 mL) at room temperature under N2 was added
KSAc (3.0 g, 26.5 mmol). The mixture was heated to reflux
for 48 h before allowing to cool to room temperature, filtered
through Celite, and concentrated. Column chromatography
(EtOAc:hexane, 1;2, Rf 0.3) gave 13 (1.57 g, 79%) as an
amorphous mass: IR 1698, 1431, 1374, 1254, 1218, 1158, 1125,
1032 cm-1; 1H NMR (CDCl3) δ 1.95, 2.00, 2.04 (3 × 3H, 3 × s,
3 × AcO), 2.31 (3H, s, AcS), 3.03 (1H, dd, J 6,6′ 14.2, J 6,5 6.9
Hz, H-6), 3.23 (1H, dd, J 6′,6 14.2, J 6′,5 2.4 Hz, H-6′), 3.46 (3H,
s, OMe), 3.57-3.61 (1H, m, H-5), 4.36 (1H, d, J 1,2 7.9 Hz, H-1),
4.88-4.96 (2H, m, H-2, H-4) 5.13 (1H, t, J 3,2 ) J 3,4 ) 9.6 Hz,
H-3); 13C NMR (CDCl3) δ 20.5, 20.7, 20.8 (OC(O)Me), 30.1 (C-
6), 30.5 (SC(O)Me), 57.0 (OMe), 68.1, 68.9, 71.2, 72.2 (C-2, C-3,
C-4, C-5), 102.1 (C-1), 169.5, 170.1, 170.4 (OC(O)Me), 194.7
(SC(O)Me); ESIMS 396 (M + NH4), 81%), 347 (60), 245 (100).
1065, 1036 cm-1; 1H NMR (CDCl3) δ 1.28 (1.29*) (3H, t, J 7.2
Hz, CO2CH2CH3), 1.41 (3H, d, J 3′,2′ 7.2 Hz, H-3′), 1.99 (3H, s,
AcO), 2.04 (6H, s, 2 × AcO), 2.72 (1H, dd, J 6,6′ 14.4, J 6,5 7.5
Hz, H-6), 2.81-2.94 (2H, m, H-6′, H-2′), 3.50 (3H, s, OMe),
3.62-3.68 (1H, m, H-5), 4.16 (4.19*) (2H, q, J 7.2 Hz, CO2CH2-
CH3), 4.40 (4.42*) (1H, d, J 1,2 7.8 Hz, H-1), 4.95 (1H, dd, J 2,3
9.3, J 2,1 7.8, H-2), 4.98 (1H, dd, J 3,4 9.6, J 3,2 9.3 Hz, H-3), 5.13-
5.21 (1H, m, H-4); 13C NMR (75.5 MHz, CDCl3) δ 14.0 (14.1*)
(CO2CH2CH3), 17.0 (C-3′), 20.5, 20.6, 20.7 (3 × OC(O)Me), 32.0
(32.7*) (C-6), 41.5 (41.9*) (C-2′), 56.8 (OMe), 61.0 (61.1*)
(CO2CH2CH3), 71.3 (71.6*), 72.7 (72.8*), 73.8, 74.6 (C-2, C-3,
C-4, C-5), 101.4 (101.5*) (C-1), 169.3, 169.5, 170.2, 172.6 (C-
1′, 3 × OC(O)Me); ESIMS 459 (M + Na, 35%), 454 (M + NH4,
100); HRESIMS Found 454.17453. C18H28O10S‚NH4 requires
454.17469.
The following were prepared in a similar manner:
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(eth yl p r op a n o-
a te)]-â-D-ga la ctop yr a n osid e (19) in 87% yield by coupling
between the 6-thiolacetyl galactoside derivative 14 and ethyl
2-bromopropionate (chromatography EtOAc:hexane, 1:2, Rf
0.3) as an amorphous mass: IR 1756, 1370, 1222, 1166, 1054
cm-1; 1H NMR (CDCl3) δ 1.27-1.31 (3H, m, CO2CH2CH3), 1.43
(1.44*) (3H, d, J 3′,2′ 7.2 Hz, H-3′), 1.97, 2.05, 2.15 (3 × 3H, 3 ×
s, 3 × AcO), 2.65 (2.76*) (1H, dd, J 6,6′ 13.8, J 6,5 6.9 Hz, H-6),
2.89 (2.98*) (1H, dd, J 6′,6 13.8, J 6′,5 7.2 Hz, H-6′), 3.38 (3.45*)
(1H, q, J 2′,3′ 7.2 Hz, H-2′), 3.52 (3H, s, OMe), 3.76 (3.79*) (1H,
dd, J 5,6′ 7.2, J 5,6 6.9 Hz, H-5), 4.17 (4.20)* (2H, q, J 7.2 Hz,
CO2CH2CH3), 4.37 (1H, d, J 1,2 7.8 Hz, H-1), 5.01 (1H, dd, J 3,2
10.2, J 3,4 3.3, H-3), 5.17 (1H, dd, J 2,3 10.2, J 2,1 7.8 Hz, H-2),
5.40 (1H, d, J 4,3 3.3 Hz, H-4); 13C NMR (75.5 MHz, CDCl3) δ
14.4 (CO2CH2CH3), 17.1 (17.4)* (C-3′), 20.8, 20.9, 21.0 (3 ×
OC(O)Me) 30.9 (31.0*) (C-6), 41.3 (41.5*) (C-2′), 56.8 (OMe),
61.1 (61.2*) (CO2CH2CH3), 69.2, 71.4, 73.5, 73.8, (C-2, C-3, C-4,
C-5), 101.9 (C-1), 169.3, 169.9 (170.0*), 170.1 (170.2*) (3 ×
OC(O)Me), 172.6 (172.7*) (C-1′); ESIMS 454 (M + NH4, 40%),
109 (100); HRESIMS Found 454.17453. C18H28O10S‚NH4 re-
quires 454.17469.
The following were prepared in a similar manner:
Meth yl 2,3,4-Tr i-O-a cetyl-6-th iola cetyl-â-D-ga la ctop y-
r a n osid e (14) in 77% yield (chromatography EtOAc:hexane,
1:2, Rf 0.3) as an amorphous mass: IR 1760, 1390, 1220, 1135,
1050 cm-1; 1H NMR (CDCl3) δ 1.97, 2.05, 2.14 (3 × 3H, 3 × s,
3 × AcO), 2.34 (3H, s, AcS), 3.06 (1H, dd, J 6,6′ 13.8, J 6,5 6.9
Hz, H-6), 3.12 (1H, dd, J 6′,6 13.8, J 6′,5 6.9 Hz, H-6′), 3.53 (3H,
s, OMe), 3.69 (1H, t, J 5,6/6′ 6.9 Hz, H-5), 4.36 (1H, d, J 1,2 7.8
Hz, H-1), 4.98 (1H, dd, J 3,2 10.2, J 3,4 3.3 Hz, H-3), 5.17 (1H,
dd, J 2,3 10.2, J 2,1 7.8 Hz, H-2), 5.41 (1H, d, J 4,3 3.3 Hz, H-4);
13C NMR (CDCl3) δ 20.4, 20.6, 20.7 (OC(O)Me), 28.5 (C-6), 30.3
(SC(O)Me), 56.9 (OMe), 68.0, 68.7, 71.0, 72.0 (C-2, C-3, C-4,
C-5), 101.9 (C-1), 169.4, 170,0, 170.2 (OC(O)Me), 194.5 (SC(O)-
Me); ESIMS 396 (M + NH4), 27%), 347 (80), 245 (100).
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(eth yl p r op a n o-
ate)]-â-D-galactopyr an osyl-(1,4)-2,3,6-tr i-O-acetyl-â-D-glu co-
p yr a n osid e (20) in 89% yield by coupling between the 6-thiol-
acetyl lactoside derivative 15 and ethyl 2-bromopropionate
(chromatography EtOAc:hexane, 1:1, Rf 0.4) as an amorphous
mass: IR 1760, 1370, 1252, 1165, 1060 cm-1; 1H NMR (CDCl3)
δ 1.25-1.31 (3H, m, CO2CH2CH3), 1.43 (1.44*) (3H, d, J 3′,2′ 7.2
Hz, H-3′), 1.96, 2.03, 2.04, 2.06, 2.13, 2.16 (6 × 3H, 6 × s, 6 ×
AcO), 2.72 (1H, dd, J 6,6′ 13.8, J 6,5 6.9 Hz, GalH-6), 2.82 (1H,
dd, J 6′,6 13.8, J 6′,5 6.9 Hz, GalH-6′), 3.48 (3H, s, OMe), 3.60-
3.67 (1H, m, GlcH-5), 3.72 (1H, t, J 5,6 ) J 5,6′ ) 6.9 Hz, GalH-
5), 3.84 (3.86*) (1H, t, J 4,3 ) J 4,5 ) 9.3 Hz, GlcH-4), 4.07 (4.10*)
(2H, q, J 7.2 Hz, CO2CH2CH3), 4.13-4.21 (2H, m, GlcH-6/6′),
4.40 (1H, d, J 1,2 8.1 Hz, GlcH-1), 4.47 (1H, d, J 1,2 7.8 Hz, GalH-
1), 4.87-4.92 (2H, m, GlcH-2, GalH-3), 5.07 (1H, dd, J 2,3 10.2,
J 2,1 7.8 Hz, GalH-2), 5.21 (1H, t, J 3,4 ) J 3,2 ) 9.3 Hz, GlcH-3),
5.39 (1H, d, J 4,3 3.3 Hz, GalH-4); 13C NMR (CDCl3) δ 14.4 (CO2-
CH2CH3), 17.3 (C-3′), 20.4, 20.5, 20.6, 20.7, 20.8 (3 × OC(O)-
Me), 30.2 (30.5*) (GalC-6), 48.3 (48.7*) (C-2′), 56.8 (OMe), 61.1
(CO2CH2CH3), 61.9 (62.0*) (GlcC-6), 69.7, 69.9, 70.4, 71.3, 71.8,
72.3, 72.7 (GlcC-2, GlcC-3, GlcC-4, GlcC-5, GalC-2, GalC-3,
GalC-4, GalC-5), 100.3, 101.4 (GlcC-1, GalC-1), 168.9, 169.5,
169.8, 170.1, 170.3, 170.8 (6 × OC(O)Me), 172.2 (C-1′); ESIMS
742 (M + NH4, 100%), 405 (25); HRESIMS Found 742.26029.
Meth yl 2,3,4-Tr i-O-a cetyl-6-th iola cetyl-â-D-ga la ctop y-
r a n osyl-(1,4)-2,3,6-tr i-O-a cetyl-â-D-glu cop yr a n osid e (15)
in 74% yield (chromatography EtOAc:hexane, 3:2, Rf 0.4) as
an amorphous mass: IR 1760, 1390, 1220, 1130, 1050 cm-1
;
1H NMR (CDCl3) δ 1.95, 2.03, 2.05, 2.08, 2.12, 2.16 (6 × 3H, 6
× s, 6 × AcO), 2.35 (3H, s, AcS), 3.04 (2H, d, J 6/6′,5 7.2 Hz,
GalH-6/6′), 3.48 (3H, s, OMe), 3.58-3.66 (2H, m, GlcH-5, GalH-
5), 3.83 (1H, t, J 4,3 ) J 4,5 ) 9.6 Hz, GlcH-4), 4.10 (1H, dd, J 6,6′
12.0, J 6,5 4.8 Hz, GlcH-6), 4.39 (1H, d, J 1,2 7.8 Hz, GlcH-1),
4.45 (1H, d, J 1,2 7.8 Hz, GalH-1), 4.50 (1H, dd, J 6′,6 12.0, J 6′,5
1.8 Hz, GlcH-6′), 4.90 (1H, dd, J 2,3 9.6, J 2,1 7.8 Hz, GlcH-2),
4.92 (1H, dd, J 3,2 9.6, J 3,4 3.0 Hz, GalH-3), 5.07 (1H, dd, J 2,3
9.6, J 2,1 7.8 Hz, GalH-2), 5.21 (1H, t, J 3,4 ) J 3,2 ) 9.6 Hz, GlcH-
3), 5.37 (1H, d, J 4,3 3.0 Hz, GalH-4); 13C (75.5 MHz, CDCl3) δ
20.1, 20.2, 20.4, 20.5, 20.6, 20.8 (OC(O)Me), 28.1 (GalC-6), 30.3
(SC(O)Me), 56.8 (OMe), 62.1 (GlcC-6), 69.1, 71.1, 71.5, 72.1,
72.3, 72.6, 72.7, 74.8 (GlcC-2, GlcC-3, GlcC-4, GlcC-5, GalC-2,
GalC-3, GalC-4, GalC-5), 100.6, 101.3 (GlcC-1, GalC-1), 168.9,
169.7, 169.9, 170.2, 173.1, 173.4 (OC(O)Me), 194.2 (SC(O)Me);
ESIMS 684 (M + NH4), 64%), 670 (40), 347 (100); Found C,
49.0; H, 5.8; S, 4.8%. C27H38O17S requires C, 48.65; H, 5.75; S,
4.8%.
C
30H44O18S‚NH4 requires 742.25921.
2. Syn th esis of Sia lylm im etics. Meth yl 2,3,4-Tr i-O-
a cetyl-6-th io-6-[2′-(eth yl p r op a n oa te)]-â-D-glu cop yr a n o-
sid e (18). A solution of the 6-thiolacetyl derivative 13 (0.5 g,
1.32 mmol) in dry N,N-DMF (10 mL) was degassed56 for 20
min. H2NNH2‚AcOH (140 mg, 1.52 mmol) was added and the
solution stirred for 30 min before the addition of ethyl
2-bromopropionate (260 mg, 1.45 mmol) and Et3N (212 µL, 1.52
mmol). After 4 h at room temperature under N2, the mixture
was diluted with EtOAc (30 mL) and washed with dilute HCl
(1 M, 30 mL) and H2O (2 × 30 mL), dried (Na2SO4), and
concentrated under reduced pressure. Chromatography (Et2O:
hexane, 2:3, Rf 0.3) gave 18 (530 mg, 92%) as colorless crystals
(Et2O/hexane): mp 98-100 °C; IR 1755, 1372, 1216, 1162,
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(m eth yl bu ta n o-
a te)]-â-D-glu cop yr a n osid e (21) in 90% yield by coupling
between the 6-thiolacetyl glucoside derivative 13 and methyl
2-bromobutyrate (chromatography EtOAc:hexane, 1:2, Rf 0.3)
as an amorphous mass: IR 1754, 1434, 1376, 1220, 1158, 1032
cm-1; 1H NMR (CDCl3) δ 0.99 (3H, t, J 4′,3′ 7.5 Hz, H-4′), 1.71-
1.83 (2H, m, H-3′), 1.99 (s, 3H, AcO), 2.05 (6H, s, 2 × AcO),
2.70 (1H, dd, J 6,6′ 14.1, J 6,5 7.5 Hz, H-6), 2.88 (1H, dd, J 6′,6 14.1,
J 6′,5 3.0 Hz, H-6′), 3.29 (1H, t, J 2′,3′ 7.8 Hz, H-2′), 3.51 (s, 3H,
OMe), 3.62 (1H, ddd, J 5,4 9.3, J 5,6 7.5, J 5,6′ 3.0 Hz, H-5), 3.73
(3.74*) (3H, s, CO2Me), 4.41 (1H, d, J 1,2 7.8 Hz, H-1), 4.94 (1H,
dd, J 2,3 9.3, J 2,1 7.8 Hz, H-2), 4.99 (1H, t, J 4,3 ) J 4,5 ) 9.3 Hz,

3298 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20
Fazli et al.
H-4), 5.17 (1H, t, J 3,4 ) J 3,2 ) 9.3 Hz, H-3); 13C NMR (CDCl3)
δ 11.8 (C-4′), 20.5, 20.6 (3 × OC(O)Me), 24.7 (C-3′), 32.5 (C-6),
48.9 (C-2′), 52.0 (OMe), 56.8 (CO2Me), 71.4, 72.7, 73.7, 74.4
(C-2, C-3, C-4, C-5), 101.4 (C-1), 169.3, 169.5, 170.1, 172.4 (3
× OC(O)Me, C-1′); ESIMS 454 (M + NH4, 70%), 405 (100%).
methyl 2-bromo-2-phenylacetate (chromatography EtOAc:hex-
ane, 1:2, Rf 0.25) as an amorphous mass: IR 3136, 2964, 2856,
1
1744, 1400, 1136, 1020 cm-1; H NMR (CDCl3) δ 1.96, 2.04,
2.11 (3 × 3H, 3 × s, 3 × AcO), 2.48 (2.53*) (1H, dd, J 6,6′ 13.8,
J 6,5 6.8 Hz, H-6), 2.69 (2.82*) (1H, dd, J 6′,6 13.8, J 6′,5 7.5 Hz,
H-6′), 3.50 (3H, s, OMe), 3.51-3.63 (1H, m, H-5), 3.73 (3.74*)
(3H, s, CO2Me), 4.27 (4.29*) (1H, d, J 1,2 7.8 Hz, H-1), 4.64
(4.81*) (1H, dd, J 3,2 10.2, J 3,4 3.3 Hz, H-3), 4.73 (4.75*) (1H, s,
H-2′), 5.13 (1H, dd, J 2,3 10.2, J 2,1 7.8 Hz, H-2), 5.31 (5.32*) (1H,
d, J 4,3 3.3 Hz, H-4), 7.29-7.46 (5H, m, Ph), assignments
confirmed by COSY; 13C NMR (CDCl3) δ 20.5, 20.7 (3 × OC-
(O)Me), 30.9 (31.6*) (C-6), 52.4 (52.7*) (C-2′), 52.5 (OMe), 56.9
(57.0*) (CO2Me), 68.5, 68.7*, 71.0, 72.9, 73.5, 74.8* (C-2, C-3,
C-4, C-5), 102.0 (102.1*) (C-1), 128.3, 128.6, 128.7, 129.3 (Ph),
139.7 (ipso-Ph), 169.4, 170.0, 170.8, 170.9 (C-1′, 3 × OC(O)-
Me); ESIMS 502 (M + NH4, 55%), 453 (100%); HRESIMS
Found 502.17473. C22H28O10S‚NH4 requires 502.17469.
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(m eth yl bu ta n o-
a te)]-â-D-ga la ctop yr a n osid e (22) in 88% yield by coupling
between the 6-thiolacetyl galactoside derivative 14 and methyl
2-bromobutyrate (chromatography EtOAc:hexane, 1:2, Rf 0.3)
as an amorphous mass: IR 1750, 1420, 1380, 1370, 1200, 1034
cm-1; 1H NMR (CDCl3) δ 0.99 (3H, t, J 4′,3′ 7.3 Hz, H-4′), 1.65-
1.92 (2H, m, H-3′), 1.97, 2.05, 2.14 (3 × 3H, 3 × s, 3 × AcO),
2.64 (2.73*) (1H, dd, J 6,6′ 13.8, J 6,5 6.3 Hz, H-6), 2.86 (2.91*)
(1H, dd, J 6′,6 13.8, J 6′,5 7.3 Hz, H-6′), 3.15 (3.23*) (1H, t, J 2′,3′
7.2 Hz, H-2′), 3.52 (3H, s, OMe), 3.73 (3H, s, CO2Me), 3.73-
3.79 (1H, m, H5), 4.37 (4.38*) (1H, d, J 1,2 7.8 Hz, H-1), 5.00
(1H, dd, J 3,2 10.2, J 3,4 3.3 Hz, H-3), 5.17 (1H, dd, J 2,3 10.2, J 2,1
7.8 Hz, H-2), 5.40 (5.42*) (1H, d, J 4,3 3.3 Hz, H-4), assignments
confirmed by COSY; 13C NMR (CDCl3) δ 11.7 (11.8*) (C-4′),
20.3, 20.4, 20.5 (3 × OC(O)Me), 24.6 (24.7*) (C-3′), 30.8 (30.9*)
(C-6), 48.3 (48.4*) (C-2′), 52.1 (OMe), 56.8 (56.9*) (CO2Me),
68.2, 68.7, 71.0, 72.6 (C-2, C-3, C-4, C-5), 102.0 (C-1), 169.3,
169.8, 170.1 (3 × OC(O)Me), 172.7 (172.8*) (C-1′); ESIMS 454
(M + NH4, 70%); HRESIMS Found 454.17471. C18H28O10S‚
NH4 requires 454.17469.
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(m eth yl 2-p h en yl-
acetate)]-â-D-galactopyranosyl-(1,4)-2,3,6-tri-O-acetyl-â-D-gluco-
p yr a n osid e (26) in 87% yield by coupling between the
6-thiolacetyl lactoside derivative 15 and methyl 2-bromo-2-
phenylacetate (chromatography EtOAc:hexane, 2:1, Rf 0.4) as
an amorphous mass: IR 2825, 1750, 1550, 1370, 1250, 1050
cm-1; 1H NMR (CDCl3) δ 1.92, 1.95, 2.02, 2.04, 2.06, 2.12 (6 ×
3H, 6 × s, 6 × AcO), 2.57 (1H, dd, J 6,6′ 13.8, J 6,5 6.9 Hz, GalH-
6), 2.70 (1H, dd, J 6′,6 13.8, J 6′,5 6.3 Hz, GalH-6′), 3.47 (3H, s,
OMe), 3.52-3.68 (2H, m, GlcH-5, GalH-5), 3.75 (3H, s, CO2-
Me), 3.84 (1H, t, J 4,3 ) J 4,5 ) 9.3 Hz, GlcH-4), 4.09-4.15 (1H,
m, GlcH-6), 4.36 (1H, d, J 1,2 7.5 Hz, GlcH-1), 4.40 (1H, d, J 1,2
8.1 Hz, GalH-1), 4.49 (1H, dd, J 6′6 11.7, J 6′,5 2.7 Hz, GlcH-6′),
4.62 (4.64*) (1H, s, H-2′), 4.88 (1H, dd, J 3,2 10.5, J 3,4 3.3 Hz,
GalH-3), 4.92-5.04 (2H, m, GlcH-2, GalH-2), 5.19 (1H, t, J 3,4
) J 3,2 ) 9.3 Hz, GlcH-3), 5.32 (5.35*) (1H, d, J 4,3 3.3 Hz, GalH-
4), 7.32-7.48 (5H, m, Ph); 13C NMR (75.5 MHz, CDCl3) δ 20.3,
20.4, 20.5, 20.6, 20.7 (6 × OC(O)Me), 30.8 (31.0*) (GalC-6),
51.9 (52.2*) (C-2′), 52.7 (OMe), 56.8 (CO2Me), 61.9 (GlcC-6),
67.9, 69.1, 71.1, 71.6, 72.5, 72.6, 75.3, (75.5*) (GlcC-2, GlcC-3,
GlcC-4, GlcC-5, GalC-2, GalC-3, GalC-4, GalC-5), 100.2 (100.3*),
101.3 (101.4*) (GlcC-1, GalC-1), 127.8, 128.1, 128.4, 128.7 (Ph),
135.3 (ipso-Ph), 169.0, 169.5, 169.7, 169.8, 170.0, 170.3, 170.8
(C-1′, 6 × OC(O)Me); ESIMS 790 (M + NH4, 100%), 748 (35%);
HRESIMS Found 790.25943. C34H44O18S‚NH4 requires
790.25921.
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(m eth yl bu ta n o-
ate)]-â-D-galactopyr an osyl-(1,4)-2,3,6-tr i-O-acetyl-â-D-glu co-
p yr a n osid e (23) in 89% yield by coupling between the
6-thiolacetyl lactoside derivative 15 and methyl 2-bromobu-
tyrate (chromatography EtOAc:hexane, 1:1, Rf 0.2) as an
1
amorphous mass: IR 1755, 1570, 1390, 1225, 1055 cm-1; H
NMR (CDCl3) δ 0.99 (1.00*) (3H, t, J 4′,3′ 7.2 Hz, H-4′), 1.64-
1.91 (2H, m, H-3′), 1.95, 2.02, 2.04, 2.06, 2.12, 2.15 (6 × 3H, 6
× s, 6 × AcO), 2.60 (2.69*) (1H, dd, J 6,6′ 13.8, J 6,5 6.3 Hz, GalH-
6), 2.80 (2.86*) (1H, dd, J 6′,6 13.8, J 6′,5 7.3 Hz, GalH-6′), 3.17
(3.19*) (1H, t, J 2′,3′ 7.2 Hz, H-2′), 3.48 (3H, s, OMe), 3.62-3.73
(2H, m, GlcH-5, GalH-5), 3.74 (3.75*) (3H, s, CO2Me), 3.86 (1H,
t, J 4,3 ) J 4,5 ) 9.3 Hz, GlcH-4), 4.08-4.15 (1H, m, GlcH-6),
4.39 (1H, d, J 1,2 7.8 Hz, GlcH-1), 4.46 (1H, d, J 1,2 8.1 Hz, GalH-
1), 4.48-4.53 (1H, m, GlcH-6′), 4.87 (1H, dd, J 2,3 9.3, J 2,1 7.8
Hz, GlcH-2), 4.94 (1H, dd, J 3,2 10.2, J 3,4 3.3 Hz, GalH-3), 5.06
(1H, dd, J 2,3 10.2, J 2,1 8.1 Hz, GalH-2), 5.21 (1H, t, J 3,4 ) J 3,2
) 9.3 Hz, GlcH-3), 5.41 (1H, d, J 4,3 3.3 Hz, GalH-4); 13C NMR
(75.5 MHz, CDCl3) δ 11.8 (C-4′), 20.3, 20.5, 20.6, 20.7 21.5 (6
× OC(O)Me), 24.5 (24.9*) (C-3′), 30.4 (30.6*) (GalC-6), 48.3
(48.7*) (C-2′), 52.3 (OMe), 57.0 (C02Me), 62.0 (GlcC-6), 67.8,
67.9, 69.1, 71.2, 71.3, 72.5, 74.7 (GlcC-2, GlcC-3, GlcC-4, GlcC-
5, GalC-2, GalC-3, GalC-4, GalC-5), 100.3, 101.3 (GlcC-1, GalC-
1), 168.9, 169.8, 170.1, 170.3, 170.8, 172.8 (C-1′, 6 × OC(O)Me);
ESIMS 742 (M + NH4, 40%), 327 (100%); HRESIMS Found
742.25802. C30H44O18S‚NH4 requires 742.25921.
Meth yl 2,3,4-Tr i-O-acetyl-6-th io-6-[2′-(γ-bu tyr olacton e)]-
â-D-glu cop yr a n osid e (27) in 86% yield by coupling between
the 6-thiolacetyl glucoside derivative 13 and R-bromo-γ-
butyrolactone (chromatography EtOAc:hexane, 2:1, Rf 0.3) as
an amorphous mass: IR 1765, 1380, 1255, 1220, 1170, 1040
1
cm-1; H NMR (CDCl3) δ 1.94, 2.03, 2.05 (3 × 3H, 3 × s, 3 ×
AcO), 2.05-2.13 (1H, m, H-3a′), 2.58-2.62 (1H, m, H-3b′), 2.68
(1H, dd, J 6,6′ 14.7, J 6,5 6.0 Hz, H-6), 3.30 (1H, dd, J 6′,6 14.7,
J 6′,5 2.7 Hz, H-6′), [3.02* (2H, d, J 6/6′,5 5.3 Hz, H-6/6′)], 3.51
(3H, s, OMe), 3.57 (3.71*) (1H, dd, J 2′,3a′ 8.5, J 2′,3b′ 4.7 Hz, H-2′),
3.73-3.81 (1H, m, H-5), 4.27-4.40 (2H, m, H-4′), 4.42 (4.43*)
(1H, d, J 1,2 7.9 Hz, H-1), 4.96 (1H, dd, J 2,3 9.3, J 2,1 7.9 Hz, H-2),
5.00 (1H, t, J 4,3 ) J 4,5 ) 9.3 Hz, H-4), 5.15 (5.17)* (1H, t, J 3,4
) J 3,2 ) 9.3 Hz, H-3), assignments confirmed by COSY; 13C
NMR (CDCl3) δ 20.6, 20.7, 20.8 (3 × OC(O)Me), 29.8 (30.0*)
(C-3′), 31.3 (32.5*) (C-6), 39.2 (39.6*) (C-2′), 57.1 (OMe), 66.6
(66.7*) (C-4′), 70.6, 71.3 (71.4*), 72.8 (72.9*), 73.8 (C-2, C-3,
C-4, C-5), 101.5 (101.6*) (C-1), 169.4 (169.5*), 169.6, 170.2
(170.3*) (3 × OC(O)Me), 175.4 (175.6*) (C-1′); ESIMS 438 (M
+ NH4, 100%), 389 (90%); HRESIMS Found 438.14349.
C17H24O10S‚NH4 requires 438.14339.
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(m eth yl 2-p h en yl-
a ceta te)]-â-D-glu cop yr a n osid e (24) in 90% yield by coupling
between the 6-thiolacetyl glucoside derivative 13 and methyl
2-bromo-2-phenylacetate (chromatography EtOAc:hexane, 1:2,
Rf 0.2) as an amorphous mass: mp 138-140 °C; IR 1753, 1372,
1
1213, 1142, 1064, 1038 cm-1; H NMR (CDCl3) δ 1.97, 1.99,
2.04 (3 × 3H, 3 × s, 3 × AcO), 2.53 (1H, dd, J 6,6′ 14.7, J 6,5 8.1
Hz, H-6), 2.64 (1H, dd, J 6′,6 14.7, J 6′,5 2.7 Hz, H-6′), 3.55 (3H,
s, OMe), 3.59-3.65 (1H, m, H-5), 3.72 (3H, s, CO2Me), 4.38
(4.40*) (1H, d, J 1,2 7.8 Hz, H-1), 4.76 (4.85*) (1H, s, H-2′), 4.87
(1H, dd, J 4,3 ) J 4,5 ) 9.3 Hz, H-4), 4.96 (1H, dd, J 2,3 9.3, J 2,1
7.8 Hz, H-2), 5.14 (5.15)* (1H, dd, J 3,4 ) J 3,2 ) 9.3 Hz, H-3),
7.30-7.46 (5H, m, Ph), assignments confirmed by COSY; 13C
NMR (CDCl3) δ 20.5, 20.6 (3 × OC(O)Me), 32.0 (32.7*) (C-6),
52.5 (52.6*) (C-2′), 52.7 (OMe), 56.9 (57.0*) (CO2Me), 71.2, 72.6,
72.7*, 73.9, 74.8 (C-2, C-3, C-4, C-5), 101.5 (C-1), 128.2, 128.4,
128.6 (Ph), 135.7 (ipso-Ph), 169.4, 170.1, 170.9 (C-1′, 3 ×
OC(O)Me); ESIMS 502 (M + NH4, 93%), 453 (100%). Found
C, 54.5; H, 5.8; S, 6.3%. C22H28O10S requires C, 54.5; H, 5.8;
S, 6.6%.
Meth yl 2,3,4-Tr i-O-acetyl-6-th io-6-[2′-(γ-bu tyr olacton e)]-
â-D-ga la ctop yr a n osid e (28) in 79% yield by coupling between
the 6-thiolacetyl glucoside derivative 14 and R-bromo-γ-
butyrolactone (chromatography EtOAc:hexane, 2:1, Rf 0.2) as
an amorphous mass: IR 1775, 1380, 1260, 1225, 1165, 1065
1
cm-1; H NMR (CDCl3) δ 1.95, 2.03, 2.13 (3 × 3H, 3 × s, 3 ×
AcO), 2.05-2.11 (1H, m, H-3a′), 2.57-2.66 (1H, m, H-3b′), 2.74
(1H, dd, J 6,6′ 14.0, J 6,5 5.8 Hz, H-6), 3.16 (1H, dd, J 6′,6 14.0,
J 6′,5 8.0 Hz, H-6′), [2.92* (2H, ABq, H-6/6′)], 3.49 (3H, s, OMe),
3.55 (1H, dd, J 2′,3a′ 8.5, J 2′,3b′ 4.9 Hz, H-2′), 3.83-3.91 (1H, m,
Meth yl 2,3,4-Tr i-O-a cetyl-6-th io-6-[2′-(m eth yl 2-p h en yl-
a ceta te)]-â-D-ga la ctop yr a n osid e (25) in 90% yield by cou-
pling between the 6-thiolacetyl galactoside derivative 14 and

Sialylmimetics as Rotavirus Inhibitors
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20 3299
H-5), 4.25-4.41 (2H, m, H-4′), 4.38 (4.39*) (1H, d, J 1,2 8.0 Hz,
H-1), 5.00 (1H, dd, J 3,2 10.2, J 3,4 3.3 Hz, H-3), 5.14 (1H, dd,
(C-1), 180.3 (C-1′); ESIMS 341 (M + Na, 30%), 319 (M + 1,
90%), 265 (100%).
J
2,3 10.2, J 2,1 8.0 Hz, H-2), 5.40 (5.41*) (1H, d, J 4,3 3.3 Hz, H-4),
Meth yl 6-Th io-6-[2′-(sod iu m bu ta n oa te)]-â-D-ga la cto-
p yr a n osid e (33) in 77% yield (reverse phase HPLC, H2O) as
an amorphous mass: IR 3450 (br), 1605, 1455, 1395, 1075
assignments confirmed by COSY; 13C NMR (CDCl3) δ 20.5,
20.6, 20.7 (3 × OC(O)Me), 29.6 (29.8*) (C-3′), 30.9 (31.0*) (C-
6), 39.3 (39.8*) (C-2′), 56.9 (OMe), 66.6 (C-4′), 68.3 (68.5*), 68.8,
71.1, 72.8 (73.1*) (C-2, C-3, C-4, C-5), 102.0 (C-1), 169.5, 170.0
(170.1*), 170.3 (170.5*) (3 × OC(O)Me), 175.2 (175.4*) (C-1′);
ESIMS 438 (M + NH4, 65%), 389 (100%). Found C, 48.2; H,
5.6; S, 7.75%. C17H24O10S requires C, 48.6; H, 5.75; S, 7.6%.
1
cm-1; H NMR (D2O) δ 0.89 (3H, t, J 4′,3′ 7.2 Hz, H-4′), 1.54-
1.78 (2H, m, H-3′), 2.76-2.82 (2H, m, H-6/6′), 3.23-3.28 (1H,
m, H-5), 3.39 (1H, dd, J 2,3 9.6, J 2,1 7.8 Hz, H-2), 3.48 (3H, s,
OMe), 3.56 (1H, dd, J 3,2 9.6, J 3,4 3.3 Hz, H-3), 3.66 (1H, t, J 2′,3′
6.6 Hz, H-2′), 3.87 (1H, d, J 4,3 3.3 Hz, H-4), 4.21 (1H, d, J 1,2
7.8 Hz, H-1); 13C NMR (D2O) 12.0 (12.1*) (C-4′), 26.3 (C-3′),
31.7 (31.8*) (C-6), 53.4 (53.7*) (C-2′), 57.8 (OMe), 70.0 (70.1*),
71.3, 73.5, 74.2 (74.7*) (C-2, C-3, C-4, C-5), 104.4 (C-1), 181.1
(C-1′); ESIMS 341 (M + Na, 100%), 319 (M + 1, 30%). Found
C, 39.0; H, 6.55; S, 9.3%. C11H19O7SNa‚H2O requires C, 39.3;
H, 6.3; S, 9.5%.
3. Dep r otection of Sia lylm im etics. Meth yl 6-Th io-6-[2′-
(sod iu m p r op a n oa te)]-â-D-glu cop yr a n osid e (29). To a
solution of 18 (200 mg, 0.46 mmol) in dry MeOH (10 mL) at
room temperature under N2 was added NaOH (1 M, 1.5 mL).
After being stirred for 15 h, the mixture was neutralized [IR-
120 (H+) resin, to pH ∼ 5] and the resin removed by filtration,
washed with aqueous MeOH, and concentrated under reduced
pressure. The residue was dissolved in H2O (10 mL) and the
pH adjusted to 7.3 with NaOH (0.5 M and then 0.05 M) before
being lyophilized. The residue was purified using HPLC
(reverse phase: H2O) to give 29 (97 mg, 70%) as an amorphous
Meth yl 6-Th io-6-[2′-(sod iu m bu ta n oa te)]-â-D-ga la cto-
p yr a n osyl-(1,4)-â-D-glu cop yr a n osid e (34) in 78% yield
(reverse phase HPLC, H2O) as an amorphous mass: IR 3460
(br), 1605, 1460, 1400, 1050 cm-1; 1H NMR (500 MHz, D2O) δ
0.87 (0.88*) (3H, t, J 4′,3′ 7.2 Hz, H-4′), 1.59-1.68 (2H, m, H-3′),
2.71 (1H, dd, J 6,6′ 13.9, J 6,5 5.5 Hz, GalH-6), 2.76-2.83 (1H,
m, GalH-6′), 3.17 (1H, t, J 2′,3′ 7.2 Hz, H-2′), 3.26 (1H, dd, J 2,3
8.7, J 2,1 8.0 Hz, GlcH-2), 3.44 (1H, dd, J 2,3 9.8, J 2,1 7.8 Hz, GalH-
2), 3.50 (3H, s, OMe), 3.55-3.61 (4H, m, GlcH-3, GlcH-4, GlcH-
5, GalH-3), 3.68-3.72 (1H, m, GalH-5), 3.74 (1H, dd, J 6,6′ 12.2,
mass: IR 3450 (br), 2932, 1615, 1460, 1395, 1070 cm-1 1H
;
NMR (D2O) δ 1.36 (3H, d, J 3′,2′ 7.2 Hz, H-3′), 2.75 (1H, dd, J 6,6′
14.1, J 6,5 8.4 Hz, H-6), 3.06 (1H, dd, 1H, J 6′,6 14.1, J 6′,5 2.7 Hz,
H-6′), 3.22-3.27 (1H, m, H-5), 3.31-3.36 (1H, m, H-4), 3.41-
3.49 (3H, m, H-2, H-3, H-2′), 3.55 (3H, s, OMe), 4.34 (1H, d,
J 1,2 7.8 Hz, H-1); 13C NMR (D2O) 18.1 (C-3′), 32.2 (32.4*) (C-
6), 45.9 (46.1*) (C-2′), 57.2 (OMe), 72.5, 72.6, 73.2, 75.5 (C-2,
C-3, C-4, C-5), 103.2 (103.5*) (C-1), 181.0 (181.1*) (C-1′);
ESIMS 305 (M + 1, 100%), 272 (60%), 251(65%); HRESIMS
Found 300.11110. C10H18O7S‚NH4 requires 300.11170.
J
6,5 4.6 Hz, GlcH-6), 3.88 (1H, d, J 4,3 3.1 Hz, GalH-4), 3.91 (1H,
d, J 6′,6 12.2 Hz, GlcH-6′), 4.34 (1H, d, J 1,2 8.0 Hz, GlcH-1), 4.38
(4.40*) (1H, d, J 1,2 7.8 Hz, GalH-1), assignments confirmed by
COSY; 13C NMR (D2O) δ 12.1 (C-4′), 26.2 (26.3*) (C-3′), 31.9
(GalC-6), 53.2 (53.7*) (C-2′), 57.6 (OMe), 60.8 (GlcC-6), 69.9,
71.4, 73.1, 73.7, 74.0, 74.6, 75.4, 79.6 (GlcC-2, GlcC-3, GlcC-4,
GlcC-5, GalC-2, GalC-3, GalC-4, GalC-5), 103.5, 103.6 (GlcC-
1, GalC-1), 181.1 (C-1′); ESIMS 503 (M + Na, 35%), 481 (M+1,
50%), 265 (65%); HRESIMS Found 476.17991. C17H30O12S‚NH4
requires 476.18017.
The following were prepared in a similar manner:
Meth yl 6-Th io-6-[2′-(sod iu m p r op a n oa te)]-â-D-ga la cto-
p yr a n osid e (30) in 71% yield (reverse phase HPLC, H2O) as
an amorphous mass: IR 3450 (br), 1610, 1465, 1405, 1365,
1210, 1080 cm-1 1H NMR (D2O) δ 1.34 (3H, d, J 3′,2′ 7.2 Hz,
;
Meth yl 6-Th io-6-[2′-(sod iu m 2′-p h en yla ceta te)]-â-D-glu -
cop yr a n osid e (35) in 88% yield (reverse phase HPLC, H2O)
as an amorphous mass: IR 3460 (br), 1605, 1455, 1390, 1070
cm-1; 1H NMR (D2O) δ 2.48 (1H, dd, J 6,6′ 14.1, J 6,5 8.1 Hz, H-6),
2.85 (1H, d, J 6′,6 14.1 Hz, H-6′), 3.10-3.26 (3H, m, H-2, H-3,
H-4), 3.33-3.44 (1H, m, H-5), 3.48 (3H, s, OMe), 4.09 (4.27*)
(1H, d, J 1,2 7.8 Hz, H-1), 4.63 (4.67*) (1H, s, H-2′), 7.27-7.38
(5H, m, Ph); 13C NMR (D2O) δ 33.0 (33.4*) (C-6), 57.4 (57.8*)
(C-2′), 57.9 (OMe), 73.2, 73.8, 75.6, 76.2 (C-2, C-3, C-4, C-5),
103.9 (C-1), 128.4, 128.9, 129.5 (Ph), 139.5 (ipso Ph), 178.0 (C-
1′); ESIMS 389 (M + Na, 67%), 367 (M + 1, 70%), 313 (100%).
Found C, 49.3; H, 5.4; S, 8.8%. C15H19O7SNa requires C, 49.2;
H, 5.2; S, 8.75%.
Met h yl 6-Th io-6-[2′-(sod iu m 2′-p h en yla cet a t e)]-â-D-
ga la ctop yr a n osid e (36) in 80% yield (reverse phase HPLC,
H2O) as an amorphous mass: IR 3480 (br), 1605, 1465, 1395,
1080 cm-1; 1H NMR (D2O) δ 2.66-2.74 (2H, m, H-6/6′), 3.26-
3.41 (3H, m, H-2, H-3, H-5), 3.44 (3H, s, OMe), 3.75 (1H, d,
J 4,3 3.3 Hz, H-4) 4.03 (4.04)* (1H, d, J 1,2 7.5 Hz, H-1), 4.71
(4.74)* (1H, s, H-2′), 7.32-7.38 (5H, m, Ph); 13C NMR (D2O) δ
31.7 (31.9)* (C-6), 57.5 (57.7*) (C-2′), 57.9 (OMe), 69.6, 71.2,
73.8, 74.3 (C-2, C-3, C-4, C-5), 104.4 (C-1), 128.5, 128.8, 129.5
(Ph), 139.9 (ipso Ph), 178.0 (C-1′); ESIMS 367 (M + 1, 60%),
313 (100%); HRESIMS Found 362.12677. C15H20O7S‚NH4
requires 362.12735.
H-3′), 2.76-2.83 (2H, m, H-6/6′), 3.40-3.46 (2H, m, H-5, H-2′),
3.52 (3H, s, OMe), 3.64 (1H, dd, J 2,3 9.3, J 2,1 7.8 Hz, H-2), 3.70-
3.74 (1H, m, H-3), 3.90-3.95 (1H, m, H-4), 4.27 (1H, d, J 1,2
7.8 Hz, H-1); 13C NMR (D2O) δ 18.6 (C-3′), 31.6 (31.8*) (C-6),
46.5 (C-2′), 57.8 (OMe), 70.0, 71.3, 73.4, 74.4 (74.7*) (C-2, C-3,
C-4, C-5), 104.4 (C-1), 181.7 (C-1′); ESIMS 327 (M + Na, 70%),
305 (40%), 272 (50%), 251(52%); HRESIMS Found 300.11112.
C
10H18O7S‚NH4 requires 300.11170.
Meth yl 6-Th io-6-[2′-(sod iu m p r op a n oa te)]-â-D-ga la cto-
p yr a n osyl-(1,4)-â-D-glu cop yr a n osid e (31) in 63% yield
(reverse phase HPLC, H2O) as an amorphous mass: IR 3500
(br), 1610, 1480, 1415, 1065 cm-1; 1H NMR (500 MHz, D2O) δ
1.30 (3H, d, J 3′,2′ 7.0 Hz, H-3′), 2.72 (1H, dd, J 6,6′ 13.9, J 6,5 5.6
Hz, GalH-6), 2.78-2.85 (1H, m, GalH-6′), 3.26 (1H, dd, J 2,3
9.1, J 2,1 8.0 Hz, GlcH-2), 3.36 (3.37*) (1H, q, J 2′,3′ 7.0 Hz, H-2′),
3.45 (1H, dd, J 2,3 9.1, J 2,1 7.8 Hz, GalH-2), 3.51 (3H, s, OMe),
3.55-3.61 (4H, m, GlcH-3, GlcH-4, GlcH-5, GalH-3), 3.69-3.75
(2H, m, GlcH-6, GalH-5), 3.89 (3.90*) (1H, d, J 4,3 3.3 Hz, GalH-
4), 3.92 (1H, d, J 6′,6 12.8 Hz, GlcH-6′), 4.34 (1H, d, J 1,2 8.0 Hz,
GlcH-1), 4.38 (4.40*) (1H, d, J 1,2 7.8 Hz, GalH-1), assignments
confirmed by COSY; 13C NMR (75.5 MHz, D2O) δ 18.4 (18.6*)
(C-3′), 31.8 (GalC-6), 46.0 (46.5*) (C-2′), 57.8 (OMe), 60.9 (GlcC-
6), 70.0 (70.1*), 71.4, 73.1, 73.4, 74.1 (74.6*), 75.1 (75.4*), 79.6
(79.8*) (GlcC-2, GlcC-3, GlcC-4, GlcC-5, GalC-2, GalC-3, GalC-
4, GalC-5), 103.6, 103.7 (GlcC-1, GalC-1), 181.6 (C-1′); ESIMS
489 (M+Na, 60%), 467 (M+1, 35%), 184 (75%); HRESIMS
Found 462.16437. C16H28O12S‚NH4 requires 462.16452.
Meth yl 6-Th io-6-[2′-(sod iu m 2′-p h en yla ceta te)]-â-D-ga -
la ct op yr a n osyl-(1,4)-â-D-glu cop yr a n osid e (37) in 81%
yield (reverse phase HPLC, H2O) as an amorphous mass: IR
1
3450 (br), 1605, 1390, 1095, 1060 cm-1; H NMR (500 MHz,
Meth yl 6-Th io-6-[2′-(sod iu m bu ta n oa te)]-â-D-glu cop y-
r a n osid e (32) in 73% yield (reverse phase HPLC, H2O) as an
amorphous mass: IR 3425 (br), 2940, 1600, 1465, 1395, 1080
D2O) δ 2.60 (1H, dd, J 6,6′ 14.0, J 6,5 6.7 Hz, GalH-6), 2.64-2.70
(1H, m, GalH-6′), 3.22-3.31 (2H, m, GlcH-2, GalH-5), 3.37-
3.41 (2H, m, GalH-2, H-2′), 3.43 (1H, dd, J 3,2 9.6, J 3,4 3.0 Hz,
GalH-3), 3.50 (3.51*) (3H, s, OMe), 3.51-3.57 (3H, m, GlcH-3,
GlcH-4, GlcH-5), 3.69 (1H, m, GlcH-6), 3.77 (3.79*) (1H, d, J 4,3
3.0 Hz, GalH-4), 3.89 (3.90*) (1H, dd, J 6′,6 12.1, J 6′,5 2.0 Hz,
GlcH-6′), 4.09 (4.18*) (1H, d, J 1,2 7.6 Hz, GalH-1), 4.32 (4.33*)
(1H, d, J 1,2 8.0 Hz, GlcH-1), 7.29-7.43 (5H, m, Ph), assign-
ments confirmed by COSY; 13C NMR (D2O) δ 30.9 (31.7*)
1
cm-1; H NMR (D2O) δ 0.88 (3H, t, J 4′,3′ 7.2 Hz, H-4′), 1.68-
1.77 (2H, m, H-3′), 2.70 (1H, dd, 1H, J 6,6′ 14.1, J 6,5 8.4 Hz, H-6),
3.05 (1H, dd, 1H, J 6′,6 14.1, J 6′,5 2.7 Hz, H-6′), 3.18-3.25 (2H,
m, H-4, H-5), 3.35-3.43 (3H, m, H-2, H-3, H-2′), 3.48 (3H, s,
OMe), 4.26 (1H, d, J 1,2 7.8 Hz, H-1); 13C NMR (D2O) 11.4 (C-
4′), 25.7 (C-3′), 32.4 (32.6*) (C-6), 52.9 (53.4*) (C-2′), 57.2
(OMe), 72.5 (72.7*), 73.2, 74.5, 75.5 (C-2, C-3, C-4, C-5), 103.2

3300 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 20
Fazli et al.
(GalC-6), 56.9 (57.1*) (C-2′), 57.2 (OMe), 60.1 (GlcC-6), 68.8,
70.7, 72.5, 72.8, 72.9, 74.3, 74.7, 78.9 (GlcC-2, GlcC-3, GlcC-4,
GlcC-5, GalC-2, GalC-3, GalC-4, GalC-5), 102.9, 103.0 (GlcC-
1, GalC-1), 127.9, 128.2, 128.9 (Ph), 139.2 (ipso Ph), 177.2 (C-
1′); ESIMS 551 (M + Na, 25%), 529 (M + 1, 30%), 265 (100%);
Con clu sion
We have clearly demonstrated an efficient synthesis
of a variety of novel sialylmimetics and have evaluated
these compounds as inhibitors of two strains of rotavi-
rus. Our results show that glucose- and galactose-based
sialylmimetics are not inhibitors of rotaviral infection.
However, on the basis of this study it appears that the
minimum epitope required for recognition by rotavirus
is a disaccharide unit with a negative charge. We are
presently investigating lactose-based sialylmimetics
with altered steric demand and hydrophobicity in order
to further explore these interesting results.
HRESIMS Found 524.18018.
524.18017.
C21H30O12S‚NH4 requires
Meth yl 6-Th io-6-[2′-(sod iu m 4′-h yd r oxy-bu ta n oa te)]-â-
D-glu cop yr a n osid e (38) in 79% yield (reverse phase HPLC,
H2O) as an amorphous mass: IR 3480 (br), 1660, 1580, 1420,
1
1060 cm-1; H NMR (D2O) δ 1.78-1.89 (1H, m, H-3′), 2.03-
2.10 (1H, m, H-3′), 2.69-2.77 (1H, m, H-2′), 2.83 (2.99*) (1H,
dd, J 6,6′ 14.1, J 6,5 6.9 Hz, H-6), 3.13-3.24 (2H, m, H-6′, H-2),
3.28-3.37 (2H, m, H-4, H-5), 3.48-3.52 (1H, m, H-3), 3.51
(3.52*) (3H, s, OMe), 4.14 (4.17*) (1H, d, J 1,2 7.6 Hz, H-1),
4.28-4.42 (2H, m, H-4′); 13C NMR (D2O) δ 32.4 (32.5*) (C-6),
34.6 (34.7*) (C-3′), 47.7 (48.1*) (C-2′), 57.2 (OMe), 59.4 (C-4′),
72.5, 73.2, 74.5, 75.5 (C-2, C-3, C-4, C-5), 103.2 (C-1), 172.7
(C-1′); ESIMS 357 (M + Na, 40%), 335 (M + 1, 70%), 281 (80%).
Ack n ow led gm en t. The authors thank the Austra-
lian Research Council for financial support and Dr.
Robin Thomson for helpful discussions. S.J .B. thanks
Monash University for a Scholarship and C.J . is thank-
ful for the award of an APRA.
Meth yl 6-Th io-6-[2′-(sod iu m 4′-h yd r oxy-bu ta n oa te)]-â-
D-ga la ctop yr a n osid e (39) in 87% yield (reverse phase HPLC,
H2O) as an amorphous mass: IR 3480 (br), 1660, 1610, 1210,
1
1065 cm-1; H NMR (D2O) δ 1.80-1.93 (1.97-2.08*) (1H, m,
Refer en ces
H-3′), 2.20-2.33 (1H, m, H-3′), 2.73-2.95 (2H, m, H-6, H-2′),
3.00 (3.14*) (1H, dd, J 6′,6 12.9, J 6′,5 7.2 Hz, H-6′), 3.48 (1H, dd,
J 2,3 9.3, J 2,1 8.1 Hz, H-2), 3.57 (3H, s, OMe), 3.65 (1H, dd, J 3,2
9.3, J 3,4 3.0 Hz, H-3), 3.72-3.84 (2H, m, H-4′), 3.93-3.98 (1H,
m, H-4), 4.31 (1H, d, J 1,2 8.1 Hz, H-1); 13C NMR (D2O) δ 30.0
(30.3*) (C-6), 31.7 (31.8*) (C-3′), 41.6 (41.8*) (C-2′), 57.8 (OMe),
60.1 (C-4′), 70.2, 71.2, 73.4, 74.5 (C-2, C-3, C-4, C-5), 104.5
(C-1), 180.2 (C-1′); ESIMS 335 (M + 1, 40%), 317 (100%).
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