A selectively deprotectable 2,6-diaminogalactose scaffold for the solid-phase synthesis of potential RNA ligands

Article abstract of DOI:10.1055/s-2008-1066982

In the context of aminoglycosides as efficient binders to RNA, a 2,6-diaminogalactose scaffold was developed for combinatorial syntheses of potential RNA ligands in the solid phase. A set of selectively removable, orthogonally stable protecting groups in combination with a linker stable throughout the synthesis, but selectively cleavable in the detachment process, allows for selective deprotection and introduction of a side chain in each position of this scaffold. A few of the synthesized compounds exhibit inhibition of HIV-1 infection in HeLa cells that contain a TAR-controlled reporter gene. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2008-1066982

1106
PAPER
A Selectively Deprotectable 2,6-Diaminogalactose Scaffold for the Solid-Phase
Synthesis of Potential RNA Ligands
D
iaminogalactose Scaf
a
fold ciej Madalinski,a Michaela Stoll,b Ursula Dietrich,b Horst Kunz*a
a
Institut für Organische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, Germany
Fax +49(6131)3924786; E-mail: hokunz@uni-mainz.de
b
Georg-Speyer-Haus – Institut für Biomedizinische Forschung, Frankfurt am Main, Paul-Ehrlich-Str. 42–44, 60596 Frankfurt am Main,
Germany
Received 12 October 2007; revised 19 December 2007
groups is required.11 In addition, a linker stable through-
out all deprotection and substitution reactions is needed if
the combinatorial syntheses are performed in solid phase.
This linker must be cleavable without the functional side
Abstract: In the context of aminoglycosides as efficient binders to
RNA, a 2,6-diaminogalactose scaffold was developed for combina-
torial syntheses of potential RNA ligands in the solid phase. A set
of selectively removable, orthogonally stable protecting groups in
combination with a linker stable throughout the synthesis, but selec- chains introduced into the scaffold during the solid-phase
tively cleavable in the detachment process, allows for selective
synthesis being affected. To meet these requirements, D-
deprotection and introduction of a side chain in each position of this
galactose was converted into the O-acetylated 2-azido-ga-
scaffold. A few of the synthesized compounds exhibit inhibition of
lactosyl nitrate 1 (Scheme 1).12 After cleavage of the O-
HIV-1 infection in HeLa cells that contain a TAR-controlled report-
nitrate with hydrazine acetate,13 and subsequent formation
er gene.
of the trichloroacetimidate 2,14 glycosylation of methyl 4-
Key words: solid-phase synthesis, RNA ligands, protecting
sulfanylbutyrate9b furnished sulfanylglycoside 3 as a mix-
groups, combinatorial chemistry, inhibition of HIV RNA
ture of anomers (a/b, 3:1) (Scheme 1).
Removal of the O-acetyl groups with catalytic sodium
methoxide in methanol and subsequent formation of the
Small molecules selectively binding to RNA are of partic-
ular interest, e.g. as potential antiviral drugs.1 Aminogly-
cosides, e.g. kanamycin, neomycin B, or tobramycin,
were shown to efficiently bind to RNA.2 These molecules
are potent inhibitors of the interaction of the HIV-1 TAR
RNA with the Tat protein.3 A variety of compounds de-
rived from aminoglycosides as the lead structures have
been investigated as ligands of RNA, including spacer-
linked dimers,4 heterocyclic derivatives,5 macrocyclic oli-
go-amino sugars,6 oligomers obtained from diamino sugar
carboxylic acids,7 and peptides rich in arginine and
lysine.8 To take advantage of a combinatorial search for
biologically active molecules, we recently developed se-
lectively deprotectable carbohydrate scaffolds for combi-
natorial syntheses in solid phase.9 As neamine is an
important substructure of aminoglycoside antibiotics, it
appeared attractive to apply this scaffold concept to di-
amino sugars.10 Amino sugar scaffolds should allow not
only for a spatial arrangement of amino groups, and there-
with positively charged groups as in natural aminoglyco-
sides, but should also offer variable opportunities to
install other side chains, e.g. intercalating groups, at the
scaffold, provided a sufficiently orthogonal protecting
group concept can be developed.
4,6-(4-methoxybenzylidene) acetal 4 was followed by 3-
O-silylation to give 5a (Scheme 1). Reduction of the azido
group with benzenethiol and tin(II) chloride15 and subse-
quent N-acetylation with allyloxycarbonyl chloride
(AlocCl) furnished 5b, which was subjected to regioselec-
tive reductive acetal opening with triethylsilane and phe-
nylboronic dichloride16 to give 6 (Scheme 1). The free 6-
hydroxy group was substituted for the azido group by a
Mitsunobu reaction using an acyl azide as the source of
the nucleophile.17 The ester group of the thus-obtained
sulfanylglycoside 7, fully protected with distinguishable
protecting groups, was saponified to furnish the carboxy-
lic acid 8 (Scheme 1), which can be used for immobiliza-
tion. Carboxylic acid 8 was coupled to Rink amide
polystyrene (100–200 mesh, 0.70 mmol/g) or Rink amide
Tentagel resin (0.23 mmol/g) by use of O-(1H-benzotria-
zol-1-yl)-N,N,N¢,N¢-tetramethyluronium hexafluorophos-
phate (HBTU)18 and N-hydroxybenzotriazole (HOBt)19 in
the presence of N,N-diisopropylethylamine (Scheme 2).
The successful attachment of the scaffold was confirmed
by the appearance of a strong IR absorption band of the
azido group at 2100 cm–1 and high-resolution magic-angle
spinning (HRMAS) NMR spectroscopy.20 In addition, the
coupling reactions were monitored by the Kaiser test and
by elemental analysis regarding sulfur. Finally, un-
changed benzhydryl amino groups were acetylated
(capped) with acetic anhydride/pyridine. The selective
deprotection reactions on the scaffolds 9 (Scheme 3) were
accomplished in analogy to the procedures described for
the 2,6-diaminoglucose template.10 The N-Aloc group
was removed by palladium(0)-catalyzed allyl transfer to
p-toluenesulfinic acid as the trapping nucleophile to af-
We here report on the elaboration of such a concept for
2,6-diamino-D-galactose as the carbohydrate framework.
For selective deprotection of a carbohydrate scaffold in
each position, a set of orthogonally stable protecting
SYNTHESIS 2008, No. 7, pp 1106–1120
x
x
.
x
x
.2
0
0
8
Advanced online publication: 06.03.2008
DOI: 10.1055/s-2008-1066982; Art ID: T16007SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1107
OH
HO
OAc
OAc
AcO
AcO
AcO
AcO
OAc
AcO
AcO
O
O
O
e, f
O
g
a–d
O
ONO2
OH
O
CCl3
NH
HO
S
OH
N3
N3
OMe
3
N3
1
2
3
MeO
MeO
j
O
h, i
O
O
O
5a R1 = TBS R2 = N3
5b R1 = TBS R2 = AlocNH
O
O
O
k, l
R1O
S
HO
OMe
O
R2
N3
3
4
S
OMe
3
OH
N3
N3
PMBO
TBSO
PMBO
TBSO
PMBO
o
m
n
O
O
O
TBSO
O
O
O
AlocHN
AlocHN
AlocHN
S
S
S
OMe
OMe
OH
6
7
3
8
3
3
Scheme 1 Reagents and conditions: (a) Ac2O, HClO4 (cat.), 100%; (b) Ac2O, AcOH, HBr, 100%; (c) N-methylimidazole, Zn, EtOAc, 74%;
(d) CAN, NaN3, MeCN, 38%; (e) H2NNH2·AcOH, DMF, 79%; (f) Cl3CCN, K2CO3, CH2Cl2, 99%; (g) HS(CH2)3CO2Me, BF3·OEt2, Et2O, 58%;
(h) NaOMe (cat.), MeOH, 100%; (i) PMPCH(OMe)2, DMF, 50 °C, 20 mbar, 55%; (j) TBSOTf, py, DMF, 5a, 99%; (k) SnCl2, PhSH, Et3N,
MeCN, 100%; (l) AlocCl, py, CH2Cl2, 5b, 90%; (m) TES, PhBCl2, 4 Å MS, –78 °C, CH2Cl2, 81%; (n) nicotinoyl azide, Ph3P, DIAD, toluene,
71%; (o) LiOH·H2O, THF–H2O (10:1), 100%.
MeO NH2
X
N3
O
MeO
PMBO
TBSO
O
O
AlocHN
S
OH
8
N3
PMBO
TBSO
X
O
O
O
AlocHN
S
N
H
MeO
9
OMe
Rink amide polystyrene (PS) or
Rink amide Tentagel® resin
9a X = -CH2-, Rink amide PS
9b X = -(O)CCH2-, Rink amide Tentagel®
=
Scheme 2 Coupling of the scaffold 8 to polymer supports
ford 10 (Scheme 3).21 Deprotection of the 3-position to butylphosphane in a tetrahydrofuran–water–triethylamine
give 11 was achieved with tetrabutylammonium hydrogen mixture was used (Scheme 3). This reaction, resulting in
difluoride solution (TBAHDF) in acetonitrile (Scheme 3). 13, as well as the removal of the N-Aloc group were mon-
The p-methoxybenzyl group was removed by selective itored by the Kaiser test. In addition, all cleavage reac-
oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzo- tions were controlled once again by FTIR and 1H HRMAS
quinone22 in dichloromethane and water (10 vol%) to fur- NMR spectroscopy.
nish 12 (Scheme 3). In the case of Rink amide polystyrene
resin, these cleavage conditions resulted in degradation of
the polymer and prevented the isolation of the desired
For the selective introduction of side chains at the 3- and
4-positions of the monosaccharide scaffold, carbamoyla-
tion (and esterification) reactions of 9a and 9b were ex-
amined (Scheme 4). Carbamoylation of the resin-linked
products from 12a. For the reduction of the azido func-
tion, a Staudinger protocol23 was applied, for which tri-n-
scaffolds 11 and 12 (obtained from 9a/9b, en route to 14
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

1108
M. Madalinski et al.
PAPER
N3
N3
PMBO
PMBO
HO
O
O
TBSO
O
O
H2N
AlocHN
S
S
N
N
H
3
3
H
10a,b
11a,b
a
c
b
d
9a,b
N3
NH2
HO
PMBO
TBSO
O
O
TBSO
O
O
AlocHN
AlocHN
S
S
N
H
N
3
3
H
12a,b
13a,b
Scheme 3 Reagents and conditions: (a) Pd(PPh3)4, TolSO2H, dioxane; (b) 50% (w/v) TBAHDF, MeCN; (c) DDQ, CH2Cl2–H2O (9:1); (d) 1.
n-Bu3P, THF; 2. THF–H2O–Et3N (2:1:1).
R4
R4
HO
HO
O
O
a–c
a–c
R2O
R2O
O
O
R1HN
R1HN
S
S
NH2
NH2
14
16, 17
9a,b
R4
R4
R3O
HO
HO
d, b, a, c
d, e, c
O
O
9a,b
R2O
O
O
R1HN
R1HN
S
S
NH2
NH2
15
18
Scheme 4 Formation of carbamates on resin-linked scaffolds 9a/b.
Reagents and conditions: (a) 50% (w/v) TBAHDF, MeCN; (b) 10%
(w/v) RNCO, DMAP (cat.), dioxane; (c) 50% TFA, CH2Cl2, MeS–
PS; (d) DDQ, CH2Cl2–H2O (9:1).
R4
HO
f, b, c
O
R2O
O
R1HN
S
NH2
and 15, respectively, Scheme 4) was performed with aryl
isocyanates in the presence of catalytic amounts of 4-
(N,N-dimethylamino)pyridine (Scheme 4). After carbam-
oylation of the 4-position, it was necessary to remove the
silyl ether with tetrabutylammonium hydrogen difluoride
prior to the release from the polymer. Otherwise the tert-
butyldimethylsilyl group is only incompletely cleaved
during the subsequent treatment with trifluoroacetic acid,
and mixtures of silylated and desilylated derivatives were
obtained. The cleavage from the solid support with 50%
trifluoroacetic acid in dichloromethane and sulfanylmeth-
yl polystyrene furnished the desired products 14 and 15
in sufficient purity and satisfying yields (Scheme 4,
Table 1).
19, 20
Scheme 5 Synthesis of O- and N-acylated diaminogalactose deriva-
tives. Reagents and conditions: (a) Pd(PPh3)4, TolSO2H, dioxane; (b)
amino acid, TBTU, HOBt·H2O, DIPEA; (c) 50% TFA, 5% Me2S,
CH2Cl2; (d) 50% (w/v) TBAHDF, MeCN; (e) amino acid, DIC,
DMAP (cat.), DMF; (f) 1. n-Bu3P, THF; 2. THF–H2O–Et3N (2:1:1).
amino groups in the 2-position (10) or 6-position (13) (to
generate 16/17 or 19/20, respectively), O-(1H-benzotriaz-
ol-1-yl)-N,N,N¢,N¢-tetramethyluronium tetrafluoroborate
(TBTU),25 N-hydroxybenzotriazole (HOBt), and N,N-di-
isopropylethylamine were used (Scheme 5).
After three or four steps, the crude amino acid– or pep-
tide–carbohydrate conjugates 16–20 were isolated as mix-
tures of the 3-hydroxy compound and its silyl ether in
satisfying yields in most cases (Scheme 5). After separa-
tion by semipreparative HPLC, their structures were con-
firmed by mass spectrometry. The values given for the
purity of products 16–20 were determined by UV absorp-
tion, and are too low owing to the presence of impurities
with large extinction coefficients. The change of the cat-
ion scavenger in the detachment reaction from sulfanyl-
As an alternative to the formation of urethanes, acylation
reactions were performed at scaffolds 10, 11, and 13 to
generate a library of amino acid– or peptide–carbohydrate
conjugates. Esterification of scaffolds 11 using N,N¢-di-
isopropylcarbodiimide in the presence of 4-(N,N-dimeth-
ylamino)pyridine according to Steglich24 gave esters 18 in
good yields (Scheme 5). Only during the reaction of 11b
(Tentagel) with Fmoc-His(Trt)-OH did some racemiza-
tion occur. For coupling of the acyl components to the free
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1109
Table 1 Synthesis of a Library of Carbamoylated Diaminogalactose Derivatives 14 and 15a
Product 14 or 15
Resin 9
9b
9b
9a
R1
R2
R3
R4
N3
N3
N3
N3
N3
N3
N3
N3
N3
N3
N3
N3
N3
N3
N3
Yieldb (%)
~100
81
Purityc (%)
14a
14b
14c
14d
14e
14f
14g
14h
14i
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
Aloc
4-FC6H4NHCO
4-NCC6H4NHCO
4-ClC6H4NHCO
3,4-ClC6H3NHCO
2,4-FC6H3NHCO
4-Me-3-O2NC6H3NHCO
4-ClC6H4NHCO
3-FC6H4NHCO
2-ClC6H4NHCO
4-EtO2CC6H4NHCO
3-AcC6H4NHCO
4-EtOC6H4NHCO
–
–
52
38
46
67
42
13
-
–
–
85
9a
–
82
9a
–
~100
34
9a
–
9a
–
31
9a
–
79
36
86
32
50
33
91
85
33
9a
–
93
14j
14k
14l
9a
–
60
9a
–
63
9a
–
98
15a
15b
15c
9b
9b
9a
4-FC6H4NHCO
4-NCC6H4NHCO
4-ClC6H4NHCO
58
–
78
–
37
a See Scheme 4 for reagents and conditions.
b Yield of crude product.
c Purities of crude products were determined by RP-HPLC (UV 210–220 nm). Since impurities can have a high extinction coefficient, these
values usually are too low.
methyl polystyrene to dimethyl sulfide solution appeared during the purification, almost all synthesized diaminoga-
advantageous. The yields as well as the purity of the pro- lactoside derivatives 14–20, except for the arginine deriv-
ducts were improved (Table 2). For the biological evalua- atives, were isolated in sufficiently pure form (by
tion of the synthesized compounds on cells in vivo, a analytical HPLC). They were obtained in amounts ade-
careful purification of products 14–20 was necessary. quate for a biological evaluation in experiments on cell
However, the solubility of compounds 14–20 in solvents cultures. It should be noted that the crude products exhib-
needed for purification by semipreparative HPLC is low, ited considerable cytotoxicity; this is obviously due to the
and caused problems. Therefore, considerable loss of the toxicity of the accompanying impurities.
synthesized products could not be prevented in the course Because of these experiences, prior to probing the antivi-
of purification.
ral effects of these compounds, their cytotoxicity had to be
investigated. The vitality of the cultured HeLa P4 cells
was monitored in terms of the concentration of ATP in all
metabolically active cells, which was measured in a lumi-
nometric assay of the ATP-dependent oxidative decar-
boxylation of luciferin at 37 °C.26 It was shown that the
purified compounds showed no cytotoxicity at a concen-
tration of 100 mM. Some of them, however, exhibited low
cytotoxicity at a concentration of 200 mM. The antiviral
effects of the synthesized carbohydrate derivatives 14–20
were determined for HeLa P4 cells that had been trans-
fected with the HIV-1 receptors CD4, CCR5, and CXCR4
and a b-galactosidase reporter gene under control of the
HIV-LTR promoter. These cells were infected with a so-
lution of the virus strain HIV-1Lai in the absence (control)
or presence of synthetic compounds 14–20 in varying
concentrations (10, 25, 50, 100, and 200 mM). The virus
proliferation was determined by measuring the galactosi-
In additional experiments, the extension of the amino acid
side chain was explored. To this end, the 9-fluorenyl-
methoxycarbonyl (Fmoc) group of the carbohydrate-
linked amino acid was removed by use of piperidine in
N,N-dimethylformamide. Subsequently, a second N-pro-
tected amino acid was coupled to give the peptide deriva-
tives 16g and 17g, 19f and 20f, and 18d–f. It is noteworthy
that the replacement of the Fmoc group by a less hydro-
phobic protecting group such as the N-benzoyloxycarbo-
nyl (Z) group afforded products 18e and 18f in
comparable yields. The sulfanylglycoside linker intro-
duced as an option for a later activation and glycoside for-
mation also has influence on the solubility of compounds
14–20. Components of a library of analogous glucose de-
rivatives containing a 3-sulfanylpropionamide showed in-
creased solubility in acetonitrile and, logically, these
compounds were easier to purify. Despite these problems
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

1110
M. Madalinski et al.
PAPER
dase reporter enzyme in a chemiluminescence assay.26 inhibition of virus proliferation even at a concentration of
Briefly summarized, the results are the following. The 3- 10 mM: Fmoc-Gly derivative 17a, 30%; Fmoc-Leu 17b,
O- and 4-O-carbamates of the diaminogalactose struc- 30%; Fmoc-Glu 17c, 45%; Fmoc-Gln 17f, 25%. The most
tures 14 and 15 exhibited no cytotoxicity in concentra- potent compound, however, belonged to the 6-N-acyl se-
tions of 200 mM, but also showed no inhibitory activity. ries 19 and 20. The N-(phenylacetyl) derivative 20e
Likewise, the 3-O-amino acid and peptide conjugates 18 caused 60% inhibition of virus production compared to
exhibit neither cytotoxicity nor an inhibitory effect, ex- the control at a concentration of 10 mM. However, only
cept for 18b, which caused 30% inhibition of virus pro- one other compound of this series 19 and 20, the Fmoc-
duction at a concentration of 200 mM. Of the 3-O-silyl-2- Gln derivative 20c, exerted weak inhibition (45% at a con-
N-amino acyl derivatives 17, some compounds showed centration of 45 mM) (Figure 1).
Table 2 Synthesis of a Library of O- and N-Acylated Diaminogalactose Derivatives 16–20a
Products 16–20
16a
17a
16b
17b
16c
Resin 9
9a
9a
9a
9a
9a
9a
9a
9a
9a
9a
9a
9a
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
9b
R1
R2
R4
Yieldb (%)
Purityc (%)
Fmoc-Gly-
Fmoc-Gly-
Fmoc-Leu-
Fmoc-Leu-
Fmoc-Glu-
Fmoc-Glu-
Fmoc-Arg-
Fmoc-Arg-
Fmoc-His-
Fmoc-His-
Fmoc-Gln-
Fmoc-Gln-
Fmoc-Arg-
Fmoc-Arg-
Fmoc-His-
Fmoc-His-
Fmoc-Gln-
Fmoc-Gln-
Fmoc-His-Gly-
Fmoc-His-Gly-
Aloc
H
N3
60
–
–
TBS
N3
40
–
H
N3
82
–
TBS
N3
33
–
H
N3
51
–
17c
TBS
N3
36
–
16d
17d
16e
H
N3
64
–
TBS
N3
–
H
N3
56
–
–
17e
TBS
N3
36
–
16f
H
N3
74
–
17f
TBS
N3
10
–
16d
17d
16e
H
N3
~100
–
TBS
N3
–
H
N3
~100
–
24
35
25
33
53
4
17e
TBS
N3
16f
H
N3
~100
–
17f
TBS
N3
16g
17g
18a
18b
18c
H
N3
~100
–
TBS
N3
Fmoc-Arg-
Fmoc-Gln-
Fmoc-His-
Fmoc-His-Gly-
Z-Gly-Gly-
Z-Gly-His-
H
N3
51
46
50
~100
~100
~100
84
–
–
Aloc
N3
43
60 (24)d
70
67
30
37
54
Aloc
N3
18d
18e
Aloc
N3
Aloc
N3
18f
Aloc
N3
19a
20a
Aloc
Fmoc-His-
Fmoc-His-
Aloc
TBS
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1111
Table 2 Synthesis of a Library of O- and N-Acylated Diaminogalactose Derivatives 16–20a (continued)
Products 16–20
Resin 9
9b
R1
R2
R4
Yieldb (%)
Purityc (%)
19b
20b
19c
20c
Aloc
Aloc
Aloc
Aloc
H
Fmoc-Arg-
Fmoc-Arg-
Fmoc-Gln-
Fmoc-Gln-
O
96
–
–
9b
TBS
H
–
9b
~100
–
21
79
9b
TBS
19d
9b
Aloc
H
~100
30
N
N
N
N
O
20d
19e
9b
9a
Aloc
Aloc
TBS
H
–
58
–
N
N
PhCH2CONH-
35
20e
19f
20f
9a
9b
9b
Aloc
Aloc
Aloc
TBS
H
PhCH2CONH-
Fmoc-His-Gly-
Fmoc-His-Gly-
–
35
34
63
~100
–
TBS
a See Scheme 5 for reagents and conditions.
b Yield of crude product.
c Purities of crude products were determined by RP-HPLC (UV 210–220 nm).
d A mixture of epimers was obtained.
The concept of selectively removable, orthogonally stable HeLa cells determined via a TAR-controlled reporter
protecting groups as given in the 2,6-diaminogalactose gene product.
scaffolds 9 allows for a selective introduction of side
chains in the scaffold in solid-phase syntheses. After three
Solvents were distilled and pre-dried according to standard proce-
dures.27 Reagents were bought in the highest available commercial
quality and used without further purification. Rink amide PS was
purchased from Novabiochem and Rink amide Tentagel from Rapp
Polymere, Tübingen, Germany. Analytical TLC was carried out on
silica gel 60 F254 (Merck). Flash chromatography was performed
(silica gel, 0.032–1.063 mm, ICN Biomedicals). IR spectra were re-
corded on a Perkin-Elmer FT-IR 1760X spectrometer. RP-HPLC
analyses were carried out on a Knauer Maxi Star HPLC system with
a Phenomenex Luna C18(2) column (5 mm, 250 × 4.60 mm), and at
a pump rate of 1 mL/min. Semipreparative RP-HPLC separations
were performed on a Knauer HPLC system with a Phenomex Luna
C18(2) column (10 mm, 250 × 21 mm), and at a pump rate of 10 mL/
min. H2O–MeCN mixtures were used as the solvents. The following
gradients were used for analytical HPLC: gradient A: H2O–MeCN,
70:30, 10 min, then 70:30 to 50:50, 2 min, then 50:50 to 30:70, 2
(or four) steps in solid phase and cleavage from the resin,
the crude compounds 14–20 were obtained in satisfying
yields. The crude products contain impurities which have
high UV extinction coefficients and cause cytotoxicity on
the cells used in in vivo inhibition experiments. Sufficient
purification of the scaffold derivatives 14–20 turned out to
be the most difficult and time-consuming procedure.
Therefore, further syntheses aimed at structure optimiza-
tion of inhibitors should preferably be performed in solu-
tion rather than on solid phase. Among the synthesized
compounds, 6-N-acyl and 2-N-aminoacyl derivatives
showed the most potent inhibition of HIV-1 infection in
N3
HO
O
O
TBSO
O
HN
HO
NH
S
O
O
NH2
TBSO
O
HN
COOH
NH
S
O
NH2
O
O
O
17c
20e
Figure 1 The most efficient inhibitors 17c and 20e of HIV-1 proliferation from the compound library 14–20
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

1112
M. Madalinski et al.
PAPER
min, then 30:70 to 0:100, 2 min, then 0:100, 23 min; gradient B:
H2O–MeCN, 70:30 to 0:100, 30 min, then 0:100, 10 min; gradient
C: H2O–MeCN, 90:10 to 0:100, 30 min, then 0:100, 10 min; gradi-
ent D: H2O–MeCN, 50:50 to 0:100, 30 min, then 0:100, 10 min. The
following gradients were used for semipreparative HPLC: gradient
E: H2O–MeCN, 70:30, 20 min, then 70:30 to 50:50, 4 min, then
50:50 to 30:70, 6 min, then 30:70 to 0:100, 4 min, then 0:100, 20
min; gradient F: H2O–MeCN, 70:30 to 0:100, 60 min, then 0:100,
15 min; gradient G: H2O–MeCN, 70:30 to 0:100, 90 min, then
a-Anomer 4a
20
Yield: 5.24 g (55%); pale yellow amorphous solid; [a]D 172.1 (c
1.0, CHCl3); Rf = 0.15 (cyclohexane–EtOAc, 4:1); Rf = 0.53 (cyclo-
hexane–EtOAc, 1:1).
IR (NaCl): 2100 (N3) cm–1.
1H NMR (400 MHz, CDCl3): d = 7.42 (d, J = 8.6 Hz, 2 H, HAr-
3
PMB), 6.90 (d, 3J = 8.8 Hz, 2 H, HAr-PMB), 5.54 (s, 1 H, CH, ace-
tal), 5.45 (d, 3J1,2 = 5.28 Hz, 1 H, H-1), 4.22 (mc, 1 H, H-6a), 4.25
(br s, 1 H, H-4) 4.10 (t, 3J1,2 = 5.28 Hz 1 H, H-2), 4.10 (mc, 1 H, H-
6b), 4.08 (br s, 1 H, H-5), 3.96–3.89 (m, 1 H, H-3), 3.81 (s, 3 H,
OCH3-PMB), 3.67 (s, 3 H, CO2CH3), 2.64 (mc, 2 H, SCH2CH2),
1
0:100, 25 min. H, 13C, and 2D NMR spectra were recorded on a
Bruker AC-300 or a Bruker AM-400 spectrometer. Centered mul-
tiplets are abbreviated as mc. Optical rotations [a]D20 were measured
on a Perkin Elmer polarimeter 241. ESI-MS spectra were measured
on a ThermoQuest Navigator instrument and FD-MS spectra on a
Finnigan-MAT 95 spectrometer.
3
2.55 (br s, 1 H, 3-OH), 2.43 (t, J = 7.2 Hz, 2 H, CH2CO2CH3),
2.00–1.92 (m, 2 H, SCH2CH2).
13C NMR (100.6 MHz, CDCl3): d = 173.4 (C=O), 160.5 (Cp-PMB),
129.8 (Ci-PMB) 127.7 (Cm-PMB), 113.8 (Co-PMB), 101.4 (CH-
PMB), 84.3 (C1), 75.2 (C4), 69.6 (C3), 69.3 (C6), 63.3 (C5), 61.3
(C2), 55.4 (OCH3-PMB), 51.8 (CO2CH3), 32.9 (CH2CO2CH3), 30.3
(SCH2CH2), 24.8 (SCH2CH2).
Methyl 4-[(3,4,6-Tri-O-acetyl-2-azido-2-deoxy-a,b-D-galactopy-
ranosyl)sulfanyl]butyrate (3)
Activated 4 Å MS (10 g) were added to a soln of 2 (19.7 g, 0.041
mol) in Et2O (750 mL). The suspension was stirred at r.t. for 1 h and
cooled to 0 °C. Methyl 4-sulfanylbutyrate (10.9 g, 0.081 mol) was
added. BF3·OEt2 (26.4 mL, 29.8 g, 0.21 mol) was dissolved in Et2O
(30 mL) and slowly added to the reaction mixture. Stirring was con-
tinued at 0 °C for 1 h and subsequently at r.t. for 6 h. After filtration
of the mixture, the filtrate was washed with sat. aq NaHCO3 (700
mL). The organic phase was washed with sat. aq NaHCO3 (3 × 500
mL), dried (MgSO4), and concentrated in vacuo. Purification of the
residue was performed by flash chromatography (silica gel, cyclo-
hexane–EtOAc, 3:1); this afforded 3.
MS (FD): m/z (%) = 439.6 (100) [M]+.
b-Anomer 4b
20
Yield: 2.58 g (27%); pale yellow amorphous solid; [a]D –23.6 (c
1.0, CHCl3); Rf = 0.05 (cyclohexane–EtOAc, 4:1); Rf = 0.20 (cyclo-
hexane–EtOAc, 1:1).
IR (NaCl): 2113 (N3) cm–1.
1H NMR (400 MHz, CDCl3): d = 7.35 (d, J = 8.6 Hz, 2 H, HAr-
3
PMB), 6.91 (d, 3J = 8.8 Hz, 2 H, HAr-PMB), 5.50 (s, 1 H, CH, ace-
tal), 4.31 (dd, 2J = 12.5 Hz, 3J = 1.4 Hz, 1 H, H-6a), 4.28 (d,
3J1,2 = 9.8 Hz, 1 H, H-1), 4.21–4.19 (m, 1 H, H-4), 4.00 (dd,
Yield: 11.0 g (58%), a/b = 3:1; colorless amorphous solid; Rf = 0.12
(cyclohexane–EtOAc, 3:1).
IR (NaCl): 2113 (N3) cm–1.
2J = 12.7 Hz, J = 1.8 Hz, 1 H, H-6b), 3.81 (s, 3 H, OCH3-PMB),
3
3.67 (s, 3 H, CO2CH3), 3.66–3.61 (m, 2 H, H-2, H-3), 3.47–3.45 (m,
1 H, H-5), 2.82 (mc, 3 H, SCH2CH2, 3-OH), 2.50 (t, 3J = 7.1 Hz, 2
H, CH2CO2CH3), 2.08–1.95 (m, 2 H, SCH2CH2).
13C NMR (100.6 MHz, CDCl3): d = 173.6 (C=O), 160.5 (Cp-PMB),
130.0 (Ci-PMB) 127.8 (Cm-PMB), 113.8 (Co-PMB), 101.5 (CH-
PMB), 83.7 (C1), 74.7 (C4), 73.4 (C3), 70.0 (C5), 69.3 (C6), 63.5
(C2), 55.4 (OCH3-PMB), 51.8 (CO2CH3), 32.7 (CH2CO2CH3), 29.3
(SCH2CH2), 25.2 (SCH2CH2).
1H NMR (400 MHz, CDCl3): d = 5.44 (d, 3J1,2 = 5.5 Hz, 0.75 H, H-
3
3
1a), 5.39 (d, J3,4 = 2.5 Hz, 0.75 H, H-4a), 5.34 (d, J3,4 = 2.6 Hz,
0.25 H, H-4b), 5.07 (dd, 3J2,3 = 11.0 Hz, 3J3,4 = 3.3 Hz, 0.75 H, H-
3a), 4.84 (dd, 3J2,3 = 10.3 Hz, 3J3,4 = 3.3 Hz, 0.25 H, H-3b), 4.52 (t,
3J5,6 = 6.2 Hz, 0.75 H, H-5a), 4.35 (d, 3J1,2 = 10.2 Hz, 0.25 H, H-1b),
3
3
4.20 (dd, J1,2 = 5.5 Hz, J2,3 = 11.0 Hz, 0.75 H, H-2a), 4.11–4.01
(m, 2 H, H-6ab), 3.85 (t, 3J5,6 = 7.0 Hz, 0.25 H, H-5b), 3.64 (s, 3.25
H, 0.25 Hb, CO2CH3), 2.87–2.49 (m, 2 H, SCH2CH2), 2.45–2.39
(m, 2 H, CH2CO2CH3), 2.11 (s, 3 H, CH3), 2.01, 2.00 (s, 6 H, CH3),
2.00–1.88 (m, 2 H, SCH2CH2).
MS (FD): m/z (%) = 439.6 (100) [M]+.
Methyl 4-{[2-Azido-3-O-(tert-butyldimethylsilyl)-2-deoxy-4,6-
O-(4-methoxybenzylidene)-a-D-galactopyranosyl]sulfanyl}bu-
tyrate (5a)
TBSOTf (3.96 mL, 4.56 g, 17.2 mmol) was added to a soln of 4a
(5.06 g, 11.5 mmol) and py (9.36 mL, 9.08 g, 115.0 mmol) in anhyd
DMF (100 mL) at 0 °C. After 20 min, the reaction mixture was add-
ed to sat. aq NaHCO3 (60 mL) at 0 °C. After addition of CH2Cl2
(100 mL) and H2O (100 mL), the organic layer was extracted with
CH2Cl2 (3 × 100 mL), dried (MgSO4), and concentrated in vacuo.
Purification by flash chromatography (silica gel) gave 5a.
13C NMR (100.6 MHz, CDCl3): d = 173.3, 170.4, 170.1, 170.0
(C=O), 85.0 (C1b), 83.5 (C1a), 74.4 (C5b), 73.0 (C3b), 70.2 (C3a),
67.5 (C4a), 67.1 (C5a), 66.6 (C4b), 61.6 (C6), 60.5 (C2b), 57.8
(C2a), 51.6 (CO2CH3), 32.7 (CH2CO2CH3, a), 32.5 (CH2CO2CH3,
b), 30.4 (SCH2CH2, b), 29.7 (SCH2CH2, a), 25.1 (SCH2CH2, b),
24.6 (SCH2CH2, a), 20.7 (3 × CH3, OAc).
MS (FD): m/z (%) = 447.7 (100) [M]+.
Methyl 4-{[2-Azido-2-deoxy-4,6-O-(4-methoxybenzylidene)-
a,b-D-galactopyranosyl]sulfanyl}butyrate (4)
Yield: 6.22 g (99%); colorless amorphous solid; [a]D20 144.5 (c 1.0,
CHCl3); Rf = 0.68 (CH2Cl2–EtOAc, 20:1); Rf = 0.73 (cyclohexane–
EtOAc, 1:1).
A soln of NaOMe in MeOH was added dropwise to a soln of 3 (9.69
g, 21.6 mmol) in anhyd MeOH (300 mL) to adjust the pH to 9.0. The
mixture was stirred for 1 h and neutralized with an acidic ion-ex-
change resin (Amberlite IR120). After filtration of the mixture, the
solvent was removed in vacuo. The residue was dissolved in anhyd
DMF (250 mL) and treated with PMPCH(OMe)2 (5.5 mL, 5.90 g,
32.4 mmol) and cat. PTSA·H2O. The reaction was carried out at 20–
30 mbar and 50 °C for 1 h. After neutralization of the mixture with
Et3N (2 mL), the solvent was removed in vacuo. The crude product
was purified by flash chromatography (silica gel, cyclohexane–
EtOAc, 4:1); this gave the a-anomer 4a as the first fraction (55%)
and the b-anomer 4b as the second fraction (27%).
IR (NaCl): 2100 (N3) cm–1.
3
1H NMR (400 MHz, CDCl3): d = 7.44 (d, J = 9.0 Hz, 2 H, HAr-
PMB), 6.89 (d, 3J = 9.0 Hz, 2 H, HAr-PMB), 5.51 (s, 1 H, CH, ace-
tal), 5.46 (d, 3J1,2 = 5.09 Hz, 1 H, H-1), 4.26–4.20 (m, 2 H, H2, H-
6a), 4.08 (mc, 1 H, H-4), 4.07 (dd, 2J = 12.5 Hz, 3J = 1.6 Hz, 1 H, H-
6b), 4.00 (br s, 1 H, H-5), 3.94 (dd, 3J2,3 = 10.2 Hz, 3J3,4 = 3.5 Hz, 1
H, H-3), 3.80 (s, 3 H, OCH3-PMB), 3.67 (s, 3 H, CO2CH3), 2.64
(mc, 2 H, SCH2CH2), 2.43 (t, 3J = 7.2 Hz, 2 H, CH2CO2CH3), 1.96
(mc, 2 H, SCH2CH2), 0.92 (s, 9 H, CH3t-Bu, TBS), 0.17 (s, 3 H, CH3,
TBS), 0.13 (s, 3 H, CH3, TBS).
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1113
13C NMR (100.6 MHz, CDCl3): d = 173.4 (C=O), 160.1 (Cp-PMB),
130.0 (Ci-PMB) 127.4 (Cm-PMB), 113.6 (Co-PMB), 100.8 (CH-
PMB), 84.6 (C1), 76.4 (C4), 70.9 (C3), 69.4 (C6), 63.6 (C5), 61.1
(C2), 55.4 (OCH3-PMB), 51.8 (CO2CH3), 32.9 (CH2CO2CH3), 30.3
aq NaHCO3 (3 × 100 mL) and 1 M HCl (100 mL) and finally stirred
with 1 M citric acid (100 mL) for 30 min. The organic layer was
separated, dried (MgSO4), and concentrated in vacuo. Purification
by flash chromatography (silica gel) afforded pure product 6.
(SCH2CH2), 25.8 (CH3t-Bu, TBS), 24.9 (SCH2CH2), 18.2 (Ct-Bu
TBS), –4.4 (CH3, TBS), –4.6 (CH3, TBS).
,
20
Yield: 840 mg (81%); colorless oil; [a]D 82.9 (c 1.0, CHCl3):
Rf = 0.10 (cyclohexane–EtOAc, 3:1).
MS (FD): m/z (%) = 553.2 (5%) [M]+, 497.0 (100%) [M – t-Bu +
3
1H NMR (400 MHz, CDCl3): d = 7.30 (d, J = 8.6 Hz, 2 H, HAr-
H]+, 420.9 (6%) [M – SCH2CH2CH2CO2CH3 + H]+.
PMB), 6.88 (d, 3J = 8.7 Hz, 2 H, HAr-PMB), 5.91 (mc, 1 H,
3
CH2=CH-, Aloc), 5.38 (d, J1,2 = 4.7 Hz, 1 H, H-1), 5.32 (d,
Methyl 4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldi-
methylsilyl)-2-deoxy-4,6-O-(4-methoxybenzylidene)-a-D-galac-
topyranosyl)sulfanyl]butyrate (5b)
3J = 16.7 Hz, 1 H, CH2=CH-, Aloc, (trans)), 5.22 (dd, 3J = 10.6 Hz,
2J = 1.3 Hz, 1 H, CH2=CH-, Aloc, (cis)), 4.96 (d, 2J = 11.1 Hz, 1 H,
PMB-CH2-Ha), (4.70 (d, 3J = 9.6 Hz, 1 H, NH-C2), 4.61–4.54 (m,
3 H, H-2, -CH2-, Aloc), 4.49 (d, 2J = 11.1 Hz, 1 H, PMB-CH2-Hb),
A soln of 5a (6.22 g, 11.2 mmol) in MeCN (100 mL) was added
dropwise to a soln of anhyd SnCl2 (3.18 g, 16.8 mmol), PhSH (6.86
mL, 7.40 g, 67.2 mmol) and Et3N (6.52 mL, 5.10 g, 50.4 mmol) in
anhyd MeCN (100 mL) at r.t. After the mixture had stirred at r.t. for
8 h, 1 M aq NaOH (150 mL) was added to it. The soln was diluted
with CH2Cl2 (150 mL) and stirred until it became colorless. The or-
ganic phase was separated, and the aqueous phase was washed with
CH2Cl2 (3 × 100 mL). The combined organic layers were dried
(MgSO4) and concentrated in vacuo. The residue was co-evaporated
with toluene (3 × 100 mL) and dried under high vacuum. The crude
amine was dissolved in anhyd CH2Cl2 (100 mL), and py (9.13 mL,
8.86 g, 112 mmol) was added to the soln. Dropwise addition of
AlocCl (2.38 mL, 2.70 g, 22.4 mmol) at 0 °C followed. After stir-
ring for 16 h at r.t., the mixture was diluted with CH2Cl2 (100 mL)
and extracted with sat. aq NaHCO3 (3 × 150 mL). The organic layer
was dried (MgSO4) and concentrated in vacuo. Purification of the
residue by flash column chromatography (silica gel) afforded pure
product 5b.
3
4.11 (t, J = 5.3 Hz, 1 H, H-5), 3.80 (s, 4 H, H-6a, OCH3-PMB),
3.73 (mc, 2 H, H-3, H-4), 3.66 (s, 3 H, CO2CH3), 3.55 (dd, 2J = 11.6
Hz, 3J = 4.5 Hz, 1 H, H-6b), 2.66 (mc, 2 H, SCH2CH2), 2.42 (mc, 2
t-Bu
H, CH2CO2CH3), 1.94 (mc, 2 H, SCH2CH2), 0.92 (s, 9 H, CH3
TBS), 0.15 (s, 3 H, CH3, TBS), 0.12 (s, 3 H, CH3, TBS).
,
13C NMR (100.6 MHz, CDCl3): d = 173.7 (C=O, Ester), 159.5 (Cp-
PMB), 155.7 (C=O, Aloc), 132.9 (-CH=CH2, Aloc), 130.5 (Ci-
PMB), 127.8 (Cm-PMB), 118.0 (-CH=CH2, Aloc), 114.0 (Co-PMB),
86.3 (br s, C1), 77.0 (C3), 74.5 (CH2-PMB), 72.5 (C5), 72.2 (C4),
65.7 (CH2, Aloc), 62.5 (C6), 55.4 (OCH3-PMB), 52.1 (C2), 51.8
t-Bu
(CO2CH3), 32.9 (CH2CO2CH3), 31.1 (SCH2CH2), 25.8 (CH3
,
TBS), 25.1 (SCH2CH2), 18.1 (Ct-Bu, TBS), –3.9 (CH3, TBS), –4.8
(CH3, TBS).
MS (FD): m/z (%) = 613.5 (100) [M]+.
Methyl 4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-(tert-
butyldimethylsilyl)-2,6-dideoxy-4-O-(4-methoxybenzyl)-a-D-
galactopyranosyl)sulfanyl]butyrate (7)
20
Yield: 5.05 g (73%, two steps); colorless oil; [a]D 123.5 (c 1.0,
CHCl3); Rf = 0.15 (cyclohexane–EtOAc, 4:1); Rf = 0.57 (cyclohex-
Ph3P (1.31 g, 5.0 mmol), DIAD (0.99 mL, 1.01g, 5.0 mmol), and
nicotinoyl azide17b (0.74 g, 5.0 mmol) were added to 6 (770 mg,
1.25 mmol) in anhyd toluene (60 mL) at r.t. The mixture was stirred
for 2 h. MeOH (20 mL) was added and the soln was concentrated in
vacuo. The residue was triturated with Et2O at 0 °C, the soln was fil-
tered, and the filtrate was concentrated in vacuo. Purification by
flash column chromatography (silica gel) gave pure azide 7.
ane–EtOAc, 1:1).
1H NMR (400 MHz, CDCl3): d = 7.45 (d, J = 8.6 Hz, 2 H, HAr-
3
PMB), 6.87 (d, 3J = 9.0 Hz, 2 H, HAr-PMB), 5.90 (mc, 1 H,
CH2=CH-, Aloc), 5.56 (d, 3J1,2 = 4.70 Hz, 1 H, H-1), 5.50 (s, 1 H,
CH, acetal), 5.30 (d, 3J = 16.2, 1 H, CH2=CH-, Aloc, (trans)), 5.19
(d, 3J = 10.6 Hz, 1 H, CH2=CH-, Aloc, (cis)), 4.73 (d, 3J = 8.2, 1 H,
NH-C2), 4.61–4.48 (m, 3 H, H-2, -CH2-, Aloc), 4.23 (dd, 2J = 12.5
Hz, 3J = 1.6 Hz, 1 H, H-6a), 4.11–4.06 (m, 2 H, H-4, H-6b), 4.01 (br
s, 1 H, H-5), 3.80 (s, 3 H, OCH3-PMB), 3.78 (mc, 1 H, H-3), 3.67 (s,
20
Yield: 499 mg (62%); colorless oil; [a]D 82.9 (c 1.0, CHCl3);
Rf = 0.10 (cyclohexane–EtOAc, 3:1).
IR (NaCl): 2102 (N3) cm–1.
3
3 H, CO2CH3), 2.67 (mc, 2 H, SCH2CH2), 2.42 (dt, J = 7.0 Hz,
2J = 2.3 Hz, 2 H, CH2CO2CH3), 1.95 (mc, 2 H, SCH2CH2), 0.85 (s,
9 H, CH3t-Bu, TBS), 0.05 (s, 6 H, 2 × CH3, TBS).
1H NMR (300 MHz, CDCl3): d = 7.28 (d, 3J = 8.9 Hz, 2 H, PMB),
6.88 (d, 3J = 8.6 Hz, 2 H, PMB), 5.91 (mc, 1 H, CH2=CH-, Aloc),
13C NMR (100.6 MHz, CDCl3): d = 173.4 (C=O, Ester), 160.5 (Cp-
PMB), 155.8 (C=O, Aloc), 132.9 (-CH=CH2, Aloc), 130.4 (Ci-
PMB), 127.7 (Cm-PMB), 117.8 (-CH=CH2, Aloc), 113.7 (Co-PMB),
100.9 (CH-PMB), 86.8 (C1), 76.3 (C4), 70.1 (C3), 69.6 (C6), 65.8
(CH2, Aloc), 63.8 (C5), 55.6 (OCH3-PMB), 51.8 (CO2CH3), 51.6
(C2), 32.9 (CH2CO2CH3), 31.2 (SCH2CH2), 25.7 (CH3t-Bu, TBS),
25.1 (SCH2CH2), 18.2 (Ct-Bu, TBS), –4.1 (CH3, TBS), –4.5 (CH3,
TBS).
3
5.31 (mc, 2 H, H-1, CH2=CH-, Aloc, (trans)), 5.21 (dd, J = 10.4
Hz, 2J = 1.4 Hz, 1 H, CH2=CH-, Aloc, (cis)), 4.98 (d, 2J = 11.0 Hz,
1 H, PMB-CH2-Ha), 4.68 (d, 3J = 9.6 Hz, 1 H, NH-C2), 4.61–4.53
(m, 3 H, H-2, -CH2-, Aloc), 4.43 (d, 2J = 11.1 Hz, 1 H, PMB-CH2-
Hb), 4.20–4.16 (m, 1 H, H-5), 3.80 (s, 3 H, OCH3-PMB), 3.74 (mc,
1 H, H-3), 3.66 (s, 3 H, CO2CH3), 3.62 (mc, 1 H, H-4), 3.55 (dd,
3J = 12.7 Hz, 2J = 8.1 Hz, 1 H, H-6a), 3.05 (dd, 3J = 12.7 Hz,
2J = 4.5 Hz, 1 H, H-6b), 2.67 (mc, 2 H, SCH2CH2), 2.43 (t, 3J = 7.3
Hz, 2 H, CH2CO2CH3), 1.95 (mc, 2 H, SCH2CH2), 0.91 (s, 9 H,
CH3t-Bu, TBS), 0.14 (s, 3 H, CH3, TBS), 0.12 (s, 3 H, CH3, TBS).
MS (FD): m/z (%) = 612.2 (100) [M + H]+, 555.1 (62) [M – t-Bu +
H]+.
13C NMR (75.5 MHz, CDCl3): d = 173.4 (C=O, Ester), 159.6 (Cp-
PMB), 155.6 (C=O, Aloc), 132.9 (-CH=CH2, Aloc), 130.5 (Ci-
PMB), 129.9 (Cm-PMB), 118.0 (-CH=CH2, Aloc), 113.9 (Co-PMB),
86.2 (br s, C1), 77.4 (C4), 74.6 (CH2-PMB), 72.2 (C3), 71.4 (C5),
65.9 (CH2, Aloc), 55.4 (OCH3-PMB), 51.8 (C2, CO2CH3), 51.3
(C6), 32.8 (CH2CO2CH3), 31.0 (SCH2CH2), 25.8 (CH3t-Bu, TBS),
25.0 (SCH2CH2), 18.0 (Ct-Bu, TBS), –3.9 (CH3, TBS), –4.9 (CH3,
TBS).
Methyl 4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldi-
methylsilyl)-2-deoxy-4-O-(4-methoxybenzyl)-a-D-galactopyra-
nosyl)sulfanyl]butyrate (6)
A suspension of acetal 5 (1.03 g, 1,68 mmol) and activated 4 Å MS
(1.0 g) in CH2Cl2 (65 mL) was stirred at r.t. for 1 h. The suspension
was cooled to –78 °C and TESH (0.81 mL, 0.586 g, 5.04 mmol) was
added dropwise. Subsequently, PhBCl2 (0.74 mL, 0.907 g, 5.71
mmol) was added. After 5 min, Et3N (2 mL) and MeOH were added
and the soln was stirred for 5 min. The cold soln was diluted with
CH2Cl2 (50 mL) and filtered, and the filtrate was washed with sat.
MS (FD): m/z (%) = 638.2 (100) [M]+.
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

1114
M. Madalinski et al.
PAPER
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-(tert-butyldi-
methylsilyl)-2,6-dideoxy-4-O-(4-methoxybenzyl)-a-D-galacto-
pyranosyl)sulfanyl]butyric Acid (8)
LiOH·H2O (0.55 g, 13.2 mmol) was added in one portion to a soln
of ester 7 (2.10 g, 3.3 mmol) in THF–H2O (10:1, 44 mL). The mix-
ture was stirred at r.t. for 16 h and neutralized with an acidic cation
exchanger (Amberlite IR120). After filtration of the mixture, the
solvent was removed in vacuo and subsequently subjected to lyo-
philization. The crude carboxylic acid 8 that was obtained was used
for coupling to the polymer support.
TBAHDF in MeCN (2.5 mL) was added, and the syringes were
shaken for 4 h. Then the resins were washed with DMF (10 mL),
DMF–MeOH (10 mL, 1:1), MeOH–CH2Cl2 (10 mL, 1:1), MeOH–
Et2O (10 mL, 1:1), and Et2O (10 mL) and dried thoroughly in vacuo.
The loaded polymers were swollen in dioxane (2.5 mL) for 30 min
and then treated with a 1% DMAP in dioxane (2 mL). After removal
of the liquid phase, twelve separate 10% solns of the appropriate
isocyanates R2NCO in dioxane (1.5 mL) were each added to one of
the resin portions and the mixtures were shaken for 16 h at r.t. The
resins were washed with dioxane (10 mL), DMF (10 mL), DMF–
MeOH (10 mL, 1:1), MeOH–CH2Cl2 (10 mL, 1:1), MeOH–Et2O
(10 mL, 1:1), and Et2O (10 mL) and dried thoroughly in vacuo. Pri-
or to cleavage of the products from the polymer supports, sulfanyl-
methyl polystyrene was added to the resins, and each polymer was
washed with anhyd CH2Cl2 (20 mL). Cleavage of products 14a–l
from the polymer supports was achieved by addition of 50% TFA
in anhyd CH2Cl2 (2.5 mL) to each of the mixtures. After 30 min of
shaking, the solns were filtered through the syringes (this step was
repeated once again). The filtrates and the corresponding washing
solns were combined separately and concentrated in vacuo. Each of
the twelve residues was dissolved in CH2Cl2 (2 mL) and filtered
over solid NaHCO3 (2 mL layer in a 5-mL solid-phase-extraction
cartridge). After filtration, the solvents were removed in vacuo and
the thus obtained products 14a–l were weighed and analyzed by
RP-HPLC and ESI-MS and purified by semipreparative RP-HPLC.
20
Yield: 1.96 g (94%); colorless oil; [a]D 93.6 (c 1.0, CHCl3);
Rf = 0.10 (cyclohexane–EtOAc, 3:1).
1H NMR (300 MHz, CDCl3): d = 7.26 (m, 2 H, PMB), 6.86 (d,
3J = 8.6 Hz, 2 H, PMB), 5.89 (mc, 1 H, CH2=CH-, Aloc), 5.30 (mc,
2 H, H-1, CH2=CH-, Aloc, (trans)), 5.20 (dd, 3J = 10.4 Hz, 2J = 1.3
Hz, 1 H, CH2=CH-, Aloc, (cis)), 4.96 (d, 2J = 10.7 Hz, 1 H, PMB-
CH2-Ha), 4.68 (d, 3J = 9.6 Hz, 1 H, NH-C2), 4.60–4.51 (m, 3 H, H-
2
2, -CH2-, Aloc), 4.54 (d, J = 10.4 Hz, 1 H, PMB-CH2-Hb), 4.20–
4.16 (m, 1 H, H-5), 3.79 (s, 3 H, OCH3-PMB), 3.72 (mc, 1 H, H-3),
3.61 (mc, 1 H, H-4), 3.53 (dd, 3J = 12.8 Hz, 2J = 8.0 Hz, 1 H, H-6a),
3.05 (dd, 3J = 12.7 Hz, 2J = 4.6 Hz, 1 H, H-6b), 2.77–2-58 (m, 2 H,
SCH2CH2), 2.46 (t, 3J = 7.1 Hz, 2 H, CH2CO2CH3), 1.94 (mc, 2 H,
SCH2CH2), 0.89 (s, 9 H, CH3t-Bu, TBS), 0.13 (s, 3 H, CH3, TBS),
0.10 (s, 3 H, CH3, TBS).
Polymer-Bound Building Blocks 9a and 9b
Resin 9a
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(4-fluorophenyl)carbamoyl]-a-D-galactopyranosyl)sulfa-
nyl]butyramide (14a)
In a solid-phase reaction vessel, Fmoc-protected Rink amide poly-
styrene (2.63 g, 1.84 mmol, loading 0.70 mmol/g, 100–200 mesh,
crosslinked with 1% divinylbenzene) was swollen in DMF (30 mL)
for 1 h, before a 50% soln of morpholine in DMF (40 mL) was add-
ed. The mixture was shaken for 30 min at r.t. The polymer was
washed with DMF and the removal of the Fmoc group was repeated.
Finally, the resin was washed with DMF and dried thoroughly in
vacuo. Carboxylic acid 8 (1.149 g, 1.84 mmol) was dissolved in
DMF (40 mL) and activated with HBTU (0.698 g, 1.84 mmol),
HOBt·H2O (0.282 g, 1.84 mmol), and DIPEA (3.4 mL, 2.38 g, 18.4
mmol). The soln was mixed for 3–5 min and finally added to the
prepared Rink amide PS. The mixture was shaken for 17 h at r.t. The
polymer was washed with DMF (10 mL), DMF–MeOH (10 mL,
1:1), MeOH–CH2Cl2 (10 mL, 1:1), MeOH–Et2O (10 mL, 1:1), and
Et2O (10 mL) and dried thoroughly in vacuo; yield: 0.67 mmol/g
(determined by elementary analysis of sulfur), corresponding to a
coupling yield of 95%. Finally, unchanged benzhydryl amino
groups were acylated with a soln of Ac2O–py (20 mL, 2:1, v/v) in
CH2Cl2 (20 mL) for 45 min. The polymer was washed with CH2Cl2
(10 mL), CH2Cl2–MeOH (10 mL, 1:1), CH2Cl2 (10 mL), and Et2O
(10 mL), and dried thoroughly in vacuo; this gave resin 9a.
Yield: 9.5 mg (ca. 100%, crude product); yellow amorphous solid.
Analytical HPLC: gradient A, tR = 16.92 min (52%).
Semipreparative HPLC: gradient E, tR = 31.02 min; yield: 3.5 mg
(45%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
ESI-MS: m/z (%) = 565.3 (7) [M + K]+, 549.3 (100) [M + Na]+,
527.3 (18) [M + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-[(4-cyanophe-
nyl)carbamoyl]-2,6-dideoxy-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (14b)
Yield: 6.5 mg (81%, crude product); yellow oil.
Analytical HPLC: gradient A, tR = 17.60 min (38%).
Semipreparative HPLC: gradient E, tR = 30.00 min; yield: 1.5 mg
(19%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
ESI-MS: m/z (%) = 572.3 (7) [M + K]+, 556.3 (100) [M + Na]+,
534.3 (25) [M + H]+.
IR (KBr): 2100 (N3) cm–1.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-[(4-chlorophe-
nyl)carbamoyl]-2,6-dideoxy-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (14c)
Resin 9b
Resin 9b was obtained by a reaction between Fmoc-protected Rink
amide Tentagel (6.391 g, 1.47 mmol, loading 0.23 mmol/g), carbox-
ylic acid 8 (0.916 g, 1.47 mmol), HBTU (0.472 g, 1.47 mmol),
BtOH·H2O (0.225 g, 1.47 mmol), and DIPEA (2.43 mL, 1.90 g,
14.7 mmol); yield: 0.19 mmol/g (determined by elementary analy-
sis regarding sulfur), corresponding to a coupling yield of 82%. The
capping reaction was carried out according to the method described
above for polymer 9a.
Yield: 31.0 mg (85%, crude product); colorless amorphous solid.
Analytical HPLC: gradient A, tR = 18.28 min (46%).
Semipreparative HPLC: gradient E, tR = 32.57 min; yield: 9.2 mg
(25%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
3
1H NMR (400 MHz, CDCl3): d = 7.20 (d, J = 8.9 Hz, 2 H, HAryl
,
carbamate), 7.11 (d, 3J = 8.9 Hz, 2 H, HAryl, carbamate), 5.67 (mc, 1
IR (KBr): 2100 (N3) cm–1.
3
H, CH2=CH-, Aloc), 5.60 (d, J = 9.3 Hz, 1 H, NH-C2), 5.31 (d,
3J = 5.4 Hz, 1 H, H-1), 5.08 (dd, J = 17.3 Hz, J = 1.3 Hz, 1 H,
CH2=CH-, Aloc, (trans)), 4.96 (dd, 3J = 10.6 Hz, 3J = 1.0 Hz, 1 H,
CH2=CH-, Aloc, (cis)), 4.69 (dd, 3J = 11.6 Hz, 3J = 2.9 Hz, 1 H, H-
3), 4.43 (mc, 1 H, H-2), 4.37 (mc, 2 H, -CH2-, Aloc), 4.22 (mc, 1 H,
H-5), 3.89 (mc, 1 H, H-4), 3.53 (dd, 2J = 12.8 Hz, 3J = 8.2 Hz, 1 H,
3
3
Carbamates 14
Ten portions of resin 9a (100 mg each, loading 0.67 mmol/g) and
two portions of resin 9b (100 mg each, loading 0.19 mmol/g) were
filled into 5-mL syringes. To each of the syringes, DMF (2.5 mL)
was added, and the polymer was swollen for 1 h. A 50% soln of
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1115
H-6a), 3.22 (mc, 1 H, H-6b), 2.58 (mc, 2 H, SCH2CH2), 2.21 (t,
3J = 7.4 Hz, 2 H, CH2CO2CH3), 1.84 (mc, 2 H, SCH2CH2).
1H NMR (400 MHz, CDCl3): d = 8.27 (d, 3J = 8.6 Hz, 1 H, HAryl),
8.08 (d, 3J = 8.6 Hz, 1 H, HAryl), 7.76 (mc, 1 H, HAryl), 7.09 (mc, 1 H,
3
H
Aryl), 5.72 (mc, 1 H, CH2=CH-, Aloc), 5.49 (d, J = 9.5 Hz, 1 H,
ESI-MS: m/z (%) = 1651.5 (2) [3M + Na]+, 1107.4 (100) [2M +
NH-C2), 5.38 (d, 3J = 5.3 Hz, 1 H, H-1), 5.13 (d, 3J = 17.3 Hz, 1 H,
Na]+, 581.1 (24) [M + K]+, 565.2 (98) [M + Na]+.
3
CH2=CH-, Aloc, (trans)), 5.00 (d, J = 10.4 Hz, 1 H, CH2=CH-,
Aloc, (cis)), 4.79 (dd, 3J = 11.5 Hz, 3J = 2.9 Hz, 1 H, H-3), 4.52 (mc,
1 H, H-2), 4.43 (mc, 2 H, -CH2-, Aloc), 4.27 (mc, 1 H, H-5), 3.98
(mc, 1 H, H-4), 3.59 (dd, 2J = 12.5 Hz, 3J = 1.6 Hz, 1 H, H-6a), 3.27
(dd, 2J = 12.9 Hz, 3J = 4.4 Hz, 1 H, H-6b), 2.62 (mc, 2 H,
SCH2CH2), 2.26 (t, 3J = 7.4 Hz, 2 H, CH2CO2CH3), 1.89 (mc, 2 H,
SCH2CH2).
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-[(3,4-dichloro-
phenyl)carbamoyl]-2,6-dideoxy-a-D-galactopyranosyl)sulfa-
nyl]butyramide (14d)
Yield: 31.8 mg (82%, crude product); colorless amorphous solid.
Analytical HPLC: gradient A, tR = 18.68 min (67%), the isolation
failed.
ESI-MS: m/z (%) = 1129.4 (44) [2M + Na]+, 1107.4 (11) [2M + H]+,
ESI-MS (crude product): m/z (%) = 1177.2 (45) [2M + Na]+, 599.1
576.2 (100) [M + Na]+, 554.2 (19) [M + H]+.
(100) [M + Na]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
{[4-(ethoxycarbonyl)phenyl]carbamoyl}-a-D-galactopyrano-
syl)sulfanyl]butyramide (14j)
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(2,4-difluorophenyl)carbamoyl]-a-D-galactopyranosyl)sulfa-
nyl]butyramide (14e)
Yield: 23.4 mg (60%, crude product); pale yellow amorphous solid.
Yield: 47.0 mg (ca. 100%, crude product); brown oil.
Analytical HPLC: gradient A, tR = 17.70 min (32%).
Analytical HPLC: gradient A, tR = 17.70 min (42%).
Semipreparative HPLC: gradient E, tR = 31.42 min; yield: 7.5 mg
(32%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
Semipreparative HPLC: gradient E, tR = 30.77 min; yield: 11.6 mg
(32%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
ESI-MS: m/z (%) = 1183.4 (100) [2M + Na]+, 1161.4 (30) [2M +
ESI-MS: m/z (%) = 1111.3 (100) [2M + Na]+, 567.1 (40) [M + Na]+,
H]+, 603.2 (92) [M + Na]+, 581.2 (2) [M + H]+.
545.2 (5) [M + H]+.
4-[(3-O-[(3-Acetylphenyl)carbamoyl]-2-{[(allyloxy)carbon-
yl]amino}-6-azido-2,6-dideoxy-a-D-galactopyranosyl)sulfa-
nyl]butyramide (14k)
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(4-methyl-3-nitrophenyl)carbamoyl]-a-D-galactopyrano-
syl)sulfanyl]butyramide (14f)
Yield: 23.3 mg (63%, crude product); pale yellow amorphous solid.
Yield: 13.0 mg (34%, crude product); brown oil.
Analytical HPLC: gradient A, tR = 16.63 min (50%).
Analytical HPLC: gradient A, tR = 19.18 min (13%).
Semipreparative HPLC: gradient E, tR = 28.67 min; yield: 5.4 mg
(14%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
ESI-MS: m/z (%) = 1673.6 (4) [3M + Na]+, 1123.4 (100) [2M +
Na]+, 1101.4 (16) [2M + H]+, 589.2 (28) [M + K]+, 573.2 (73) [M +
Na]+, 551.2 (2) [M + H]+.
Semipreparative HPLC: gradient E, tR = 31.87 min; yield: 0.8 mg
(2%, based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 606.2 (19) [M + K]+, 590.2 (100) [M + Na]+,
568.2 (5) [M + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(4-nitrophenyl)carbamoyl]-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (14g)
Yield: 11.6 mg (31%, crude product); pale yellow amorphous solid.
The desired product could not be detected.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(4-ethoxyphenyl)carbamoyl]-a-D-galactopyranosyl)sulfa-
nyl]butyramide (14l)
Yield: 36.1 mg (98%, crude product); pale yellow amorphous solid.
Analytical HPLC: gradient A, tR = 17.55 min (33%).
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(3-fluorophenyl)carbamoyl]-a-D-galactopyranosyl)sulfa-
nyl]butyramide (14h)
Semipreparative HPLC: gradient E, tR = 31.45 min; yield: 9.8 mg
(27%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
Yield: 28.0 mg (79%, crude product); pale yellow amorphous solid.
ESI-MS: m/z (%) = 1144.4 (7) [2M + K]+, 1127.4 (78) [2M + Na]+,
Analytical HPLC: gradient A, tR = 18.58 min (36%).
1105.4 (100) [2M + H]+, 575.2 (62) [M + Na]+, 553.2 (2) [M + H]+.
Semipreparative HPLC: gradient E, tR = 31.87 min; yield: 8.8 mg
(25%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
Carbamates 15
One portion of resin 9a (100 mg, loading 0.67 mmol/g) and two por-
tions of resin 9b (100 mg each, loading 0.15 mmol/g) were filled in
5-mL syringes. To each of the syringes CH2Cl2 (2.5 mL) was added,
and the polymers were swollen for 1 h. A mixture of DDQ (158.9
mg, 0.70 mmol for 9a or 52.2 mg, 0.23 mmol for 9b) in CH2Cl2 (2.5
mL) and 10 vol% H2O were added to the polymers. The syringes
were shaken for 30 min. The resins were washed thoroughly with
CH2Cl2 (10 mL) and an additional portion of DDQ was added. After
30 min the polymer support was washed with DMF (10 mL), DMF–
MeOH (10 mL, 1:1), MeOH–CH2Cl2 (10 mL, 1:1), MeOH–Et2O
(10 mL, 1:1), and Et2O (10 mL) and directly used for carbamoyla-
tion. The preparation of the carbamates was carried out according to
the protocol for the preparation of derivatives 14. The procedures
for the removal of the TBS protecting group and the cleavage of the
ESI-MS: m/z (%) = 1075.4 (89) [2M + Na]+, 1053.4 (100) [2M +
H]+, 549.2 (64) [M + Na]+, 527.2 (8) [M + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-
[(2-nitrophenyl)carbamoyl]-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (14i)
Yield: 34.6 mg (93%, crude product); pale yellow amorphous solid.
Analytical HPLC: gradient A, tR = 18.67 min (86%).
Semipreparative HPLC: gradient E, tR = 31.68 min; yield: 15.3 mg
(41%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

1116
M. Madalinski et al.
PAPER
desired products from polymer support were performed as de-
scribed for the isolation of carbamates 14. The products 15 thus ob-
tained were weighed and analyzed by RP-HPLC and ESI-MS and
purified by semipreparative RP-HPLC.
the six residues cold Et2O (1 mL) was added, and the mixtures were
kept cold at 0 °C for 5 min. The solns were carefully removed and
the residues were dried in vacuo. Mixtures of the desilylated 16 and/
or silylated 17 products were obtained, analyzed by RP-HPLC and
ESI-MS, and purified by semipreparative RP-HPLC.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-4-O-
[(4-fluorophenyl)carbamoyl]-a-D-galactopyranosyl)sulfa-
nyl]butyramide (15a)
The reactions on Tentagel were carried out according to the above
protocol, starting from polymer 9b (1.5 g, 0.345 mmol), by use of
TolSO2H (270 mg, 1.73 mmol), Pd(PPh3)4 (79.7 mg, 0.69 mmol),
TBTU (73.8 mg, 0.23 mmol), HOBt·H2O (35.2 mg, 0.23 mmol),
DIPEA (78.7 mL, 59.4 mg, 0.46 mmol), and Fmoc-Arg(Pmc)-OH,
Fmoc-His(Trt)-OH, and Fmoc-Gln(Trt)-OH (0.23 mmol, respec-
tively). For the synthesis of products 16g and 17g the procedure re-
quired additional steps. Before the product was cleaved from the
resin, the Fmoc protecting group was removed as described for the
preparation of building blocks 9, and the coupling of Fmoc-
His(Trt)-OH (0.23 mmol) followed according to the peptide-cou-
pling protocol given above.
Yield: 4.6 mg (58%, crude product); colorless amorphous solid.
Analytical HPLC: gradient A, tR = 18.25 min (91%).
Semipreparative HPLC: gradient E, tR = 31.07 min; yield: 1.9 mg
(24%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
ESI-MS: m/z (%) = 565.3 (5) [M + K]+, 549.3 (100) [M + Na]+,
527.3 (20) [M + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-4-O-[(4-cyanophe-
nyl)carbamoyl]-2,6-dideoxy-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (15b)
4-[(6-Azido-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-2-{[N-(9-
fluorenylmethoxycarbonyl)-glycyl]amino}-a-D-galactopyrano-
syl)sulfanyl]butyramide (17a)
Yield: 6.2 mg (78%, crude product); colorless amorphous solid.
Yield: 26.6 mg (60%, crude product); brown amorphous solid.
Analytical HPLC: gradient A, tR = 17.60 min (85%).
Analytical HPLC: gradient A, tR = 25.72 min (40%).
Semipreparative HPLC: gradient E, tR = 30.00 min; yield: 1.1 mg
(14%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
Semipreparative HPLC: gradient F, tR = 31.45 min; yield: 5.3 mg
(12% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 572.3 (5) [M + K]+, 556.3 (100) [M + Na]+,
534.3 (10) [M + H]+.
ESI-MS: m/z (%) = 1435.7 (13) [2M + K]+, 1419.7 (87) [2M + Na]+,
721.3 (100) [M + Na]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-4-O-[(4-chlorophe-
nyl)carbamoyl]-2,6-dideoxy-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (15c)
4-[(6-Azido-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-2-{[N-(9-
fluorenylmethoxycarbonyl)-L-leucyl]amino}-a-D-galactopyra-
nosyl)sulfanyl]butyramide (17b)
Yield: 13.3 mg (37%, crude product); pale brown amorphous solid.
Yield: 39.2 mg (82%, crude product); brown amorphous solid.
Analytical HPLC: gradient A, tR = 18.07 min (33%).
Analytical HPLC: gradient A, tR = 27.85 min (33%), not isolated by
semipreparative HPLC.
Semipreparative HPLC: gradient E, tR = 32.57 min; yield: 3.8 mg
(10%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
ESI-MS (crude product): m/z (%) = 793.11 (10) [M + K]+, 777.18
(100) [M + Na]+, 663.21 (25) [3-OH, M + Na]+.
ESI-MS: m/z (%) = 1629.4 (4) [3M + H]+, 1107.4 (7) [2M + Na]+,
1085.4 (100) [2M + H]+, 565.2 (10) [M + Na]+, 543.2 (16) [M + H]+.
4-[(6-Azido-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-2-{[N-(9-
fluorenylmethoxycarbonyl)-L-glutamyl]amino}-a-D-galactopy-
ranosyl)sulfanyl]butyramide (17c)
N-Acylated Derivatives 16 and 17
In a solid-phase reaction vessel, resin 9a (1.3 g, 1.84 mmol, loading
0.70 mmol/g) was swollen for 1 h in anhyd dioxane (20 mL). The
mixture was degassed by ultrasonication under an argon atmo-
sphere, before TolSO2H (0.781 g, 4.58 mmol) was added. Pd(PPh3)4
(0.213 g, 0.184 mmol) was added and the mixture was shaken in the
dark at r.t for 16 h. Polymer support 10a was washed with dioxane
(10 mL), DMF (10 mL), CH2Cl2 (10 mL), MeOH–CH2Cl2 (10 mL,
1:1), CH2Cl2–Et2O (10 mL, 1:1), and Et2O (10 mL), and dried thor-
oughly in vacuo. Amino acids Fmoc-Gly-OH, Fmoc-Leu-OH,
Fmoc-Glu(Ot-Bu)-OH, Fmoc-Arg(Pmc)-OH, Fmoc-His(Trt)-OH,
and Fmoc-Gln(Trt)-OH (5 equiv, 0.35 mmol) were each activated
with TBTU (112.0 mg, 0.35 mmol), HOBt·H2O (54.0 mg 0.35
mmol), and DIPEA (0.115 mL, 90.0 mg, 0.70 mmol) in DMF (2.5
mL). One of the solns of activated amino acids was added to each
of six 5-mL syringes containing resin 10a (100 mg each), and the
mixtures were shaken at r.t. for 16 h. Finally, the polymer support
was washed with DMF (10 mL), DMF–MeOH (10 mL, 1:1),
MeOH–CH2Cl2 (10 mL, 1:1), MeOH–Et2O (10 mL, 1:1), and Et2O
(10 mL) and then dried thoroughly in vacuo. Prior to cleavage of the
products from the polymer support, the polymers were washed with
anhyd CH2Cl2 (20 mL). Cleavage of the products from the polymer
support was achieved by addition of 50% TFA and 5% Me2S soln
in anhyd CH2Cl2 (2.5 mL). After 30 min of shaking, the solns were
filtered from the syringes (this step was repeated once again). Each
of the solns was combined and concentrated in vacuo. To each of
Yield: 24.9 mg (51%, crude product); brown amorphous solid.
Analytical HPLC: gradient A, tR = 22.72 min (36%).
Semipreparative HPLC: gradient F, tR = 30.10 min; yield: 4.8 mg
(10% based on polymer-bound carbohydrate); pale yellow amor-
phous solid.
ESI-MS: m/z (%) = 809.26 (100) [M + K]+, 793.31 (40) [M + Na]+.
4-[(6-Azido-2,6-dideoxy-2-{[N-(9-fluorenylmethoxycarbonyl)-
L-arginyl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide
(16d) and Its 3-OTBS Derivative 17d
From reaction on aminomethyl-PS: Yield: 31.5 mg (64%, crude
product); brown amorphous solid; desired product not detected.
From reaction on Tentagel resin: Yield: 23.9 mg (ca. 100%).
Analytical HPLC: gradient B, tR = 10.68 min (12%), 12.36 min
(17%), 16.33 min (29%), 19.73 min (7%). This gave mixture of 16d
and 17d; separation of products and isolation failed.
ESI-MS (crude product): m/z (%) = 798.59 (30) [M + H]+ (17d),
684.52 (20) [M + H]+ (16d), 576.50 (15) [M – Fmoc + H]+ (17d),
420.20 (5) [2-NH2, M – Fmoc-Arg]+ (17d), 195.04 (100%), 179.05
(65) [DBF + H]+.
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1117
4-[(6-Azido-2,6-dideoxy-2-{[N-(9-fluorenylmethoxycarbonyl)-
L-histydyl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide
(16e)
Semipreparative HPLC: gradient G, tR = 16.92 min; yield: 1.2 mg
(8% based on polymer-bound carbohydrate); colorless amorphous
solid.
From reaction on Tentagel resin: Yield: 19.8 mg (ca. 100%, crude
product), yellow oil.
ESI-MS: m/z (%) = 836.52 (100) [M + H]+, 637.38 (15) [M –
Fmoc + Na + 1]+, 584.44 (25), 263.42 (50), 179.07 (20) [DBF + H]+.
Analytical HPLC: gradient B, tR = 10.62 min (24%).
O-Acylated Derivatives 18
Semipreparative HPLC: gradient G, tR = 20.32 min; yield: 3.9 mg
(31% based on polymer-bound carbohydrate); colorless amorphous
solid.
Six portions of resin 9b (100 mg each, loading 0.19 mmol/g) were
placed in six 5-mL syringes, and the above-described procedure for
the removal of the TBS protecting group (preparation of carbamates
14) was applied. The appropriate Fmoc- and Z-terminated amino
acids (0.23 mmol each) were activated with DIC (47.4 mL, 37.9 mg,
0.23 mmol) and DMAP (2.6 mg, 0.21 mmol) in DMF (2.5 mL) and
then added to the polymers. After shaking of the mixtures for 16 h
at r.t., the polymer supports were washed with DMF (10 mL),
DMF–MeOH (10 mL, 1:1), MeOH–CH2Cl2 (10 mL, 1:1), MeOH–
Et2O (10 mL, 1:1), and Et2O (10 mL) and dried thoroughly in vacuo.
The cleavage of the products from the polymer support was carried
out according to the procedure described for preparation of deriva-
tives 16 and 17. The synthesis of derivatives 18d–f contained addi-
tional steps, which are described in the protocol for the preparation
of compounds 16g and 17g. Products 18 thus obtained were ana-
lyzed by RP-HPLC and ESI-MS and purified by semipreparative
RP-HPLC.
ESI-MS: m/z (%) = 687.49 (5) [M + Na]+, 665.49 (100) [M + H]+,
179.05 (5) [DBF + H]+.
4-[(6-Azido-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-2-{[N-(9-
fluorenylmethoxycarbonyl)-L-histydyl]amino}-a-D-galactopyr-
anosyl)sulfanyl]butyramide (17e)
From reaction on Tentagel resin.
Analytical HPLC: gradient B, tR = 17.08 min (35%).
Semipreparative HPLC: gradient G, tR = 50.73 min; yield: 1.0 mg
(7% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 779.57 (100) [M + Na]+, 557.47 (5) [M –
Fmoc + H]+.
4-[(6-Azido-2,6-dideoxy-2-{[N-(9-fluorenylmethoxycarbonyl)-
L-glutaminyl]amino}-a-D-galactopyranosyl)sulfanyl]butyra-
mide (16f)
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-[N-
(9-fluorenylmethoxycarbonyl)-L-arginyl]-a-D-galactopyrano-
syl)sulfanyl]butyramide (18a)
Yield: 21.6 mg (ca. 100%, crude product), yellow amorphous solid.
Yield: 7.4 mg (51%, crude product); colorless amorphous solid; the
isolation failed.
Analytical HPLC: gradient B, tR = 11.37 min (25%), 24. 47 min
ESI-MS (crude product): m/z (%) = 768.38 (100) [M + H]+.
(26%).
Semipreparative HPLC: gradient G tR = 18.67 min; yield: 1.0 mg
(7% based on polymer-bound carbohydrate); pale yellow amor-
phous solid.
ESI-MS: m/z (%) = 678.48 (8) [M + Na]+, 472.32 (15) [M –
Fmoc+K]+, 456.31 (40) [M – Fmoc+Na]+, 434.26 (100) [M –
Fmoc + H]+, 195.05 (35%), 179.05 (60) [DBF + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-[N-
(9-fluorenylmethoxycarbonyl)-L-glutaminyl]-a-D-galactopyra-
nosyl)sulfanyl]butyramide (18b)
Yield: 6.5 mg (46%, crude product); colorless amorphous solid.
Analytical HPLC: gradient B, tR = 15.92 min (43%).
Semipreparative HPLC: gradient E, tR = 25.77 min; yield: 0.8 mg
(6%, based on polymer-bound carbohydrate); colorless amorphous
solid.
4-[(6-Azido-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-2-{[N-(9-
fluorenylmethoxycarbonyl)-L-glutaminyl]amino}-a-D-galacto-
pyranosyl)sulfanyl]butyramide (17f)
Analytical HPLC: gradient B, 21.12 min (33%), not isolated by
semipreparative HPLC.
ESI-MS: m/z (%) = 1501.58 (64) [2M + Na]+, 778.27 (3) [M + K]+,
762.28 (100) [M + Na]+.
ESI-MS (crude product): m/z (%) = 770.55 (5) [M + Na]+, 656.44
(5) [M + H]+ (16f), 548.42 (<5) [M – Fmoc + H]+, 434.26 (10)
[M – Fmoc + H]+ (16f), 179.05 (100) [DBF + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-[N-
(9-fluorenylmethoxycarbonyl)-L-histydyl]-a-D-galactopyrano-
syl)sulfanyl]butyramide (18c)
Yield: 7.1 mg (50%, crude product); colorless amorphous solid.
4-[(6-Azido-2,6-dideoxy-2-{[N-(9-fluorenylmethoxycarbonyl)-
L-histydyl-l-glycyl]amino}-a-D-galactopyranosyl)sulfanyl]bu-
tyramide (16g)
Analytical HPLC: gradient B, tR = 17.27 min (60%, major epimer
18c), tR = 18.30 min (24%, minor epimer 18c*).
Semipreparative HPLC: gradient A, tR = 29.00 min (18c); yield: 1.8
mg (13%, based on polymer-bound carbohydrate); colorless amor-
phous solid.
Yield: 24.9 mg (~100%, crude product); colorless amorphous solid.
Analytical HPLC: gradient B, tR = 13.52 min (53%).
Semipreparative HPLC: gradient G, tR = 16.92 min; yield: 1.2 mg
(9% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 1519.59 (39) [2M + Na]+, 1497.61 (6) [2M +
Na]+, 787.27 (3) [M + K]+, 771.29 (100) [M + Na]+, 749.31 (16)
[M + H]+.
ESI-MS: m/z (%) = 722.45 (100) [M + H]+, 695.49 (<5%, 6-NH2,
Semipreparative HPLC: gradient A, tR = 31.13 min (18c*); yield:
0.4 mg (3%, based on polymer-bound carbohydrate); colorless
amorphous solid.
ESI-MS: m/z (%) = 1519.60 (10) [2M + Na]+, 787.28 (6) [M + K]+,
771.29 (61) [M + Na]+, 749.31 (100) [M + H]+, 412.15 (3) [M –
Fmoc – His – 3-TBSO + Na]+.
[M + H]+, 434.26 (40%), 263.42 (85%).
4-[(6-Azido-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-2-{[N-(9-
fluorenylmethoxycarbonyl)-L-histydyl-glycyl]amino}-a-D-ga-
lactopyranosyl)sulfanyl]butyramide (17g)
Analytical HPLC: gradient B, tR = 20.45 min (4%).
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

1118
M. Madalinski et al.
PAPER
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-2,6-dideoxy-3-O-[N-
(9-fluorenylmethoxycarbonyl)-L-histydyl-glycyl]-a-D-galacto-
pyranosyl)sulfanyl]butyramide (18d)
Yield: 26.6 mg (ca. 100%, crude product); colorless amorphous sol-
id.
Analytical HPLC: gradient B, tR = 13.22 min (37%).
Semipreparative HPLC: gradient G, tR = 13.28 min; yield: 1.6 mg
(12% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 745.32 (15) [M + Na]+, 723.36 (20) [M – H]+,
Analytical HPLC: gradient B, tR = 12.10 min (5%), 14.97 min
(70%, 18d), 17.10 min (17%), 20.23 min (5%).
604.35 (50), 179.05 (100) [DBF + H]+.
Semipreparative HPLC: gradient G, tR = 19.15 min; yield: 6.1 mg
(40% based on polymer-bound carbohydrate); colorless amorphous
solid.
4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldimethylsi-
lyl)-2,6-dideoxy-6-{[N-(9-fluorenylmethoxycarbonyl)-L-histy-
dyl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide (20a)
Analytical HPLC: gradient B, tR = 22.67 min (54%).
ESI-MS: m/z (%) = 828.33 (100) [M + Na]+, 806.36 (24) [M + H]+,
412.16 (14) [3-OH, M + Na]+.
Semipreparative HPLC: gradient G, tR = 28.65 min; yield: 2.5 mg
(16% based on polymer-bound carbohydrate); colorless amorphous
solid.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-[N-(benzyloxy-
carbonyl)-glycyl-glycyl]-2,6-dideoxy-a-D-galactopyranosyl)sul-
fanyl]butyramide (18e)
Yield: 13.7 mg (ca. 100%, crude product); colorless amorphous sol-
id; cleavage of product from polymer support with a TFA–H2O–
TIPS–CH2Cl2 mixture (50:5:5:40).
ESI-MS: m/z (%) = 856.46 (5) [M + Ca]2+, 742.36 (65) [3-OH, M +
Ca]2+, 604.35 (40), 179.04 (100) [DBF + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-2,6-dideoxy-6-{[N-(9-fluor-
enylmethoxycarbonyl)-L-arginyl]amino}-a-D-galactopyrano-
syl)sulfanyl]butyramide (19b)
Analytical HPLC: gradient B, tR = 10.67 min (7%), 11.08 min
(67%, 18e), 12.80 min (4%), 13.40 min (21%); the isolation failed.
Yield: 15.6 mg (96%); yellow amorphous solid.
ESI-MS: m/z (%) = 660.30 (20) [M + Na]+, 91.08 (100) [PhCH2]+.
Analytical HPLC: gradient B, tR = 7.53 min (44%), 15.00 min
(14%), 17.17 min (42%); the isolation failed.
4-[(2-{[(Allyloxy)carbonyl]amino}-6-azido-3-O-[N-(benzyloxy-
carbonyl)-glycyl-L-histydyl]-2,6-dideoxy-a-D-galactopyrano-
syl)sulfanyl]butyramide (18f)
Yield: 14.1 mg (ca. 100%, crude product); colorless amorphous sol-
id; cleavage of product from polymer support with a TFA–H2O–
TIPS–CH2Cl2 mixture (50:5:5:40).
ESI-MS (crude product): m/z (%) = 764.32 (5) [M + Na]+, 742.34
(10) [M + H]+, 500.12 (5) [6-NH2, M – Fmoc-Arg + Na]+, 179.03
(100) [DBF + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldimethylsi-
lyl)-2,6-dideoxy-6-{[N-(9-fluorenylmethoxycarbonyl)-L-argin-
yl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide (20b)
The desired product could not be detected.
Analytical HPLC: gradient C, tR = 11.32 min (30%).
Semipreparative HPLC: gradient G, tR = 20.63 min; yield: 1.8 mg
(13% based on polymer-bound carbohydrate); colorless amorphous
solid.
4-[(2-{[(Allyloxy)carbonyl]amino}-2,6-dideoxy-6-{[N-(9-fluor-
enylmethoxycarbonyl)-L-glutaminyl]amino}-a-D-galactopyra-
nosyl)sulfanyl]butyramide (19c)
Yield: 16.2 mg (ca. 100%, crude product); colorless amorphous sol-
id.
ESI-MS: m/z (%) = 756.17 (20) [M + K]+, 740.20 (100) [M + Na]+,
412.14 (5) [3-OH, M + Na]+.
N-Acylated Derivatives 19 and 20
Analytical HPLC: gradient B, tR = 12.90 min (21%).
One portion of resin 9a (100 mg, loading 0.67 mmol/g) and five por-
tions of resin 9b (100 mg each, loading 0.19 mmol/g) were each
placed separately in one of six 5-mL syringes. To each of the sy-
ringes, THF (2.5 mL) was added, and the polymer was swollen for
1 h. A soln of n-Bu3P (0.115 mL, 0.46 mmol, for 9a or 0.349 mL for
9b) in a THF–H2O–Et3N mixture (2:1:1, 2.5 mL) was added to each
of the syringes, which were then shaken for 2 h. This step was re-
peated once again, and the resin was washed with DMF (10 mL),
DMF–MeOH (10 mL, 1:1), MeOH–CH2Cl2 (10 mL, 1:1), MeOH–
Et2O (10 mL, 1:1), and Et2O (10 mL) and dried thoroughly in vacuo.
The N-acylation was carried out according to the protocol for the
synthesis of compounds 16 and 17; the following carboxylic acids
were used: phenylacetic acid (0.23 mmol), Fmoc-His(Trt)-OH
(0.70 mmol), Fmoc-Arg(Pmc)-OH (0.70 mmol), Fmoc-Gln(Trt)-
OH (0.70 mmol), 1-phenyl-1H-[1,2,3]triazole-4-carboxylic acid
(0.70 mmol), and Fmoc-Gly-OH (0.70 mmol). The cleavage of the
products from the polymer support was carried out according to the
procedure described for preparation of derivatives 16 and 17. The
synthesis of 19f and 20f required additional steps, as described in
the protocol for the preparation of compounds 16g and 17g. Prod-
ucts 19 and 20 thus obtained were analyzed by RP-HPLC and ESI-
MS and purified by semipreparative RP-HPLC.
Semipreparative HPLC: gradient G, tR = 19.08 min; yield: 0.9 mg
(7% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 736.43 (10) [M + Na]+, 697.86 (20) [M – NH2]+,
641.74 (50), 401.38 (85), 360.41 (100).
4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldimethylsi-
lyl)-2,6-dideoxy-6-{[N-(9-fluorenylmethoxycarbonyl)-L-
glutaminyl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide
(20c)
Analytical HPLC: gradient B, tR = 21.72 min (79%).
Semipreparative HPLC: gradient G, tR = 46.70 min; yield: 1.7 mg
(11% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 850.49 (45) [M + Na]+, 828.58 (5) [M + H]+,
628.41 (80) [M – Fmoc + Na]+, 606.48 (90) [M – Fmoc + H]+,
469.41 (95), 179.07 (100) [DBF + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-2,6-dideoxy-6-{[(1-phenyl-
1H-1,2,3-triazol-4-yl)carbonyl]amino}-a-D-galactopyrano-
syl)sulfanyl]butyramide (19d)
4-[(2-{[(Allyloxy)carbonyl]amino}-2,6-dideoxy-6-{[N-(9-fluor-
enylmethoxycarbonyl)-L-histydyl]amino}-a-D-galactopyrano-
syl)sulfanyl]butyramide (19a)
Yield: 14.4 mg (ca. 100%, crude product); colorless oil.
Analytical HPLC: gradient B, tR = 10.78 min (30%).
Yield: 13.4 mg (84%, crude product); pale yellow amorphous solid.
Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York

PAPER
Diaminogalactose Scaffold
1119
Semipreparative HPLC: gradient G, tR = 11.65 min; yield: 1.9 mg
(19% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 557.37 (100) [M + Na]+, 406.25 (45).
References
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4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldimethylsi-
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yl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide (20d)
Analytical HPLC: gradient B, tR = 20.62 min (58%).
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Semipreparative HPLC: gradient G, tR = 44.4 min; yield: 1.0 mg
(8% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 671.51 (100) [M + Na]+, 406.25 (40).
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Jaunzems, J.; Michaelis, K.; Kalesse, M.; Kirschning, A.;
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4-[(2-{[(Allyloxy)carbonyl]amino}-2,6-dideoxy-6-[(phenyl-
acetyl)amino]-a-D-galactopyranosyl)sulfanyl]butyramide (19e)
Yield: 13.0 mg (35%, crude product); brown amorphous solid. The
desired product could not be detected.
4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldimethylsi-
lyl)-2,6-dideoxy-6-[(phenylacetyl)amino]-a-D-galactopyrano-
syl)sulfanyl]butyramide (20e)
Analytical HPLC: gradient A, tR = 25.98 min (35%).
Semipreparative HPLC: gradient E, tR = 24.93 min; yield: 1.9 mg
(5% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 618.17 (100) [M + Na]+, 596.13(<5) [3-TBSO,
M + H]+.
(7) Sicherl, F.; Wittmann, V. Angew. Chem. Int. Ed. 2005, 44,
2096.
(8) (a) Krebs, A.; Ludwig, V.; Boden, O.; Göbel, M. W.
ChemBioChem 2003, 4, 972. (b) Pustowka, A.; Dietz, J.;
Ferner, J.; Baumann, M.; Landersz, M.; Königs, C.;
Schwalbe, H.; Dietrich, U. ChemBioChem 2003, 4, 1093.
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W.; Kunz, H. Angew. Chem. Int. Ed. 1998, 37, 2503.
(b) Kallus, C.; Opatz, T.; Wunberg, T.; Schmidt, W.; Henke,
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T.; Kallus, C.; Wunberg, T.; Schmidt, W.; Henke, S.; Kunz,
H. Eur. J. Org. Chem. 2003, 1527.
(10) (a) Hünger, U.; Ohnsmann, J.; Kunz, H. Angew. Chem. Int.
Ed. 2004, 43, 1104. (b) Ohnsmann, J.; Madalinski, M.;
Kunz, H. Chim. Oggi 2005, 16.
(11) For a recent review, see: Meutermanns, W.; Li, G. T.;
Becker, B. ChemMedChem 2006, 1, 1164.
4-[(2-{[(Allyloxy)carbonyl]amino}-2,6-dideoxy-6-{[N-(9-fluor-
enylmethoxycarbonyl)-L-histydyl-glycyl]amino}-a-D-galacto-
pyranosyl)sulfanyl]butyramide (19f)
Yield: 18.8 mg (~100%, crude product); colorless amorphous solid.
Analytical HPLC: gradient B, tR = 12.42 min (34%).
Semipreparative HPLC: gradient G, tR = 19.15 min; yield: 2.9 mg
(20% based on polymer-bound carbohydrate); colorless amorphous
solid.
ESI-MS: m/z (%) = 802.4 (15) [M + Na]+, 780.42 (100) [M + H]+,
558.47 (10) [M – Fmoc + H]+, 179.07 (50) [DBF + H]+.
4-[(2-{[(Allyloxy)carbonyl]amino}-3-O-(tert-butyldimethylsi-
lyl)-2,6-dideoxy-6-{[N-(9-fluorenylmethoxycarbonyl)-L-histy-
dyl-glycyl]amino}-a-D-galactopyranosyl)sulfanyl]butyramide
(20f)
(12) Lemieux, R. U.; Ratcliff, R. M. Can. J. Chem. 1979, 57,
1244.
Analytical HPLC: gradient B, tR = 20.47 min (63%).
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1826.
Semipreparative HPLC: gradient G, tR = 46.62 min; yield: 2.2 mg
(13% based on polymer-bound carbohydrate); colorless amorphous
solid.
(15) Batra, M.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron
ESI-MS: m/z (%) = 916.59 (5) [M + H]+, 894.67 (100) [M + H]+,
672.59 (<5) [3-TBSO, M – Fmoc + H]+, 543.36 (60), 466.94 (40),
179.07 (10) [DBF + H]+.
1990, 46, 587.
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Acknowledgment
This work was supported by Sonderforschungsbereich (SFB) 579 of
the Deutsche Forschungsgemeinschaft (DFG).
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Synthesis 2008, No. 7, 1106–1120 © Thieme Stuttgart · New York