The Amadori rearrangement as key reaction for the synthesis of neoglycoconjugates

Article abstract of DOI:10.1016/j.carres.2008.02.022

The Amadori rearrangement was introduced as a key step for the conjugation of carbohydrate moieties with suitable amines such as aliphatic amines and amino acid derivatives. The rearrangement products were further transformed into the corresponding 1-N,2-O cyclic carbamates employing triphosgene to obtain anomerically stable glycoconjugates. The reaction conditions were probed on a model substrate, 3,5-di-O-benzyl-α,β-d-glucofuranose and further applied to d-glycero-d-gulo-heptose, which gave 'd-gluco-conjugates' in the α-anomeric form exclusively in high isolated yields.

Full text of DOI:10.1016/j.carres.2008.02.022

Available online at www.sciencedirect.com
Carbohydrate Research 343 (2008) 2057–2066
The Amadori rearrangement as key reaction for the synthesis
of neoglycoconjugates
Tanja M. Wrodnigg,* Christiane Kartusch and Carina Illaszewicz
Glycogroup, Institut fu¨r Organische Chemie, Technische Universita¨t Graz, Stremayrgasse 16, A-8010 Graz, Austria
Received 15 October 2007; received in revised form 20 February 2008; accepted 26 February 2008
Available online 2 March 2008
Presented at Eurocarb 14th Lubeck, Germany, September 2007
¨
Abstract—The Amadori rearrangement was introduced as a key step for the conjugation of carbohydrate moieties with suitable
amines such as aliphatic amines and amino acid derivatives. The rearrangement products were further transformed into the corres-
ponding 1-N,2-O cyclic carbamates employing triphosgene to obtain anomerically stable glycoconjugates. The reaction conditions
were probed on a model substrate, 3,5-di-O-benzyl-a,b-D-glucofuranose and further applied to D-glycero-D-gulo-heptose, which
gave ‘D-gluco-conjugates’ in the a-anomeric form exclusively in high isolated yields.
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords: Amadori rearrangement; Carbohydrate-amino acid conjugate; Neoglycoconjugate; Protein modification
OH
1. Introduction
O
OH
OH
O
HO
HO
H2NR, H+
NH-R
The Amadori rearrangement1 (Scheme 1), the reaction
between aldoses such as D-glucose (1) and suitable
amines, leads to 1-amino-1-deoxy ketoses (2) and is
known as the first and initial step of the Maillard reac-
tion cascade,2 the non-enzymatic browning of food.
Additionally, this reaction is a form of post-transla-
tional modification of biomolecules which has been
linked to diseases such as diabetes, cataract, Alzhei-
mer’s, dialysis related amylosis, atherosclerosis and
Parkinson’s diseases as well as physiological aging.3
The preparative use of this rearrangement is rather
limited because of many difficulties accompanying the
reaction: several steps during the isomerisation are
reversible and a range of side products can be formed.
Additionally, it is difficult to isolate the rearrangement
product from the obtained compound mixture and unre-
acted starting materials. Furthermore, the rearrange-
ment product can occur as a mixture of furanoid and
pyranoid a- and b-anomers. The product itself can enter
HO
OH
OH
OH
1
2
Scheme 1. Amadori rearrangement.
the Maillard reaction cascade2 pathway to give corres-
ponding side and degradation products. Consequently,
only a few preparatively useful examples for this reac-
tion are known in the literature.4 However, the Amadori
rearrangement allows for simple introduction of an
amine onto position C-1 of a carbohydrate moiety and
does not require any protecting group manipulation.
With the acceptance and appreciation of the impor-
tance of the carbohydrate part of biomolecules, protein
modification, such as the synthesis of glycoconjugates
and neoglycoconjugates,5 has been addressed exten-
sively during recent years. Glycoconjugates—structures
where carbohydrate units are covalently bound to bio-
molecules such as peptides, proteins or lipids—are ubiqui-
tous in all living organisms and do participate in the
cell–cell communication, recognition as well as signalling
*
Corresponding author. Tel.: +43 316 873 8744; fax: +43 316 873
8740; e-mail: t.wrodnigg@tugraz.at
0008-6215/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2008.02.022

2058
T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
processes based on carbohydrate–carbohydrate or
carbohydrate–protein Furthermore,
interactions.6
Based on this findings 3,5-di-O-benzyl-a,b-D-gluco-
furanose (5)15 was selected as a model compound for
probing the reaction conditions of the rearrangement
with free aliphatic amines, amine hydrochlorides as well
as free and protected amino acid derivatives. The substi-
tution pattern should allow easy rearrangement to the
pyranoid 1-amino-1-deoxyketose, which is expected to
occur in the b-anomeric form. Additionally, the two
benzyl groups permit tracking of the reaction by UV
and are rather unpolar groups, which should enable eas-
ier purification of the desired products from the reaction
mixture by silica gel chromatography as well as better
identification. For aliphatic amines such as dibenzyl-
amine, benzylamine and 6-aminohexanol 1 equiv of
acetic acid in ethanol was applied for the Amadori
rearrangement. Contrasting with our observation to
obtain only the respective b-anomers of the rearrange-
ment products, we isolated a/b-mixtures with almost
every amines employed such as with compounds 6
(1:3, 71%), 7 (2:7, 55%) and 8 (1:4, 52%), respectively
(Scheme 3). In contrast to compound 4, structures 6, 7
as well as 8 have two rather large substituents, which
might be responsible for the formation of both anomeric
forms in the 5C2 and 2C5 conformation for the a- and b-
anomer, respectively. In both forms two substituents are
found in axial positions whereas the 1-amino substituent
takes the sterically more convenient equatorial position.
With amine hydrochlorides, addition of 1 equiv of
Et3N, which initiates the liberation of the free amine
from its hydrochloride form, turned out beneficial in
terms of rearrangement product formation. Further-
more, this prevents glycoside formation of the free
aldose with the alcohol used. Under these conditions,
the hydrochlorides of 6-amino hexanoic acid methyl
ester and L-glycine benzyl ester were reacted successfully
with model aldose 5. Again, a/b-mixtures of compounds
9 (1:2) and 10 (1:3) were formed (Scheme 4). Isolated
yields turned out to be low, the reaction had to be
stopped with a notable amount of starting material
remaining in order to avoid too much degradation.
Additionally, the purification turned out to be very
difficult, careful chromatography was necessary to
obtain analytically pure samples for characterisation.
Other reaction conditions, such as in the absence of
carbohydrate modification influences the physiological
behaviour of therapeutic compounds such as their life
time, absorption or penetration in physiological systems
dramatically. For example, it was shown that modifica-
tion of insulin by just one sugar residue improved its
intestinal adsorption as well as resistance against enzy-
matic degradation in vivo.7 Reliable methods for the
synthesis of glycoconjugates and neoglycoconjugates
allow for the preparation of sufficient quantities of pure
materials compared to the typical mixtures obtained
from tedious isolation techniques.8 Different chemical9
as well as enzymatic10 synthetic approaches were intro-
duced for the selective modification of biomolecules in
the literature. To synthesise conjugates, which are not
sensitive towards hydrolysis, such as the naturally
occurring O- and N-glycosidic linkages, the synthesis
of stable C-glycosyl compounds11 became yet another
important synthetic target, which are thought to have
great therapeutic potential.12
Here we report the development of a method for the
modification of amino acid derivatives using the Ama-
dori rearrangement as a key reaction for the synthesis
of C-glycosyl analogues of glycoconjugates. Probing of
the reaction conditions as well as product characterisa-
tion was performed on a model substrate 5, the devised
methods were applied to heptose 16 for the synthesis of
D-gluco configured carbohydrate-amino acid conjugates.
Such structures can find use as building blocks for clas-
sical peptide synthesis. The method can also be applied
for selective modification of lysine residues in peptides
and smaller proteins.
2. Results and discussion
During our synthetic studies towards C-1 amino deriva-
tives of the powerful glucosidase inhibitor 2,5-imino-2,5-
dideoxy-D-mannitol,13 we found that the Amadori rear-
rangement of 5-azido-5-deoxy-a,b-D-glucofuranose 3
gave excellent preparative isolated yields of the corres-
ponding 1-amino-5-azido-1,5-dideoxy-b-D-fructose 414
(Scheme 2). In this particular case, only the pyranoid
form of compound 4 can be formed because of the azido
substituent at position C-5. The relatively bulky diben-
zylamine at position C-1 prefers the equatorial position
in the b-form.
OH
OBn
BnO
O
NR1R2
HO
O
OH
a or b or c
BnO
OBn
OH
OH
N3
OH
O
5
6: R1 = R2 = Bn
HNBn2, H+
HO
NBn2
O
OH
OH
7: R1 = H, R2 = Bn
8: R1 = H, R2 = (CH2)6OH
N3
OH
EtOH, 40 °C
HO
OH
Scheme 3. Reagents and conditions: (a) HNBn2, AcOH, EtOH, 71%;
(b) H2NBn, AcOH, EtOH, 55%; (c) H2N(CH2)6OH, AcOH, EtOH,
52%.
3
4
Scheme 2. Preparative application of the Amadori rearrangement.

T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
2059
The yields obtained for the Amadori rearrangement
of the model compound 5 and in some cases for the
cyclic carbamate formation turned out to be unexpected
low. We think that this was caused by the nature of the
very polar products obtained as well as degradation pro-
cesses under the reaction conditions employed. Silica gel
chromatography was performed as the purification pro-
tocol, but was clearly showing limits for such highly po-
lar compounds. Despite preparative problems with the
model compound 5 we decided to apply the reaction
conditions to D-glycero-D-gulo-heptose 16 aiming at su-
gar amino acid conjugates featuring D-gluco configura-
tion in the carbohydrate moiety.
OH
OBn
O
HO
O
NHR
a or b
OH
OH
BnO
OBn
BnO
OH
5
9: R = (CH2)5COOMe
10: R = CH2COOBn
Scheme 4. Reagents and conditions: (a) H2N(CH2)5COOMe, Et3N,
EtOH, 25%; (b) H2NCH2COOBn, Et3N, EtOH, 15%.
catalyst, with AcOH, NaOAc or NaHCO3, gave either
no reaction at all or almost complete degradation of
the starting materials.
Partially protected Cbz-Lys-OH was reacted without
any addition of acid, the carboxylic acid function itself
providing the acidic catalyst for the isomerisation
(Scheme 5). Interestingly, in this particular case only
the b-anomer 11 of the rearrangement product was iso-
lated, although the yield was very low due to solubility
problems of the reactants and tedious purification by
silica gel chromatography. From the TLC only one
adequate rearrangement product was seen.
Next, the reaction conditions for the formation of a 1-
N,2-O-cyclic carbamate with triphosgene16 was investi-
gated. Addition of 1,4-dioxane to the aqueous reaction
system for better solubility, as well as a large excess of
Na2CO3 to buffer, turned out to improve the conversion.
Compounds 12–14 were isolated as a/b-anomeric mix-
tures ranging between 1:1 and 1:4 in yields of 80%,
30% and 27%, respectively. However, compound 15
was isolated as a pure b-anomer in 65% yield (Scheme
6).
The reaction of this commercially available heptose
gave good to excellent isolated yields in most cases of
the pure a-anomer for the rearrangement products 17
(93%), 18 (95%), 19 (80%), 20 (82%) and 22 (73%)
(Scheme 7). The all-equatorial arrangement of the
hydroxyl groups in the product representing D-gluco-
configuration was expected to be a strong driving force
for the product formation in this particular case. Fur-
thermore, in the a-anomeric form the 5C2 pyranoid con-
formation allows the amino substituent to occupy the
more comfortable equatorial position. However,
employing L-glycine benzyl ester hydrochloride, only a
moderate yield of 55% was obtained for the rearrange-
ment product 21.
Formation of the corresponding cyclic carbamates
was achieved by employing the reaction conditions
probed on the model compound leading to pure a-ano-
meric forms of the respective 1-amino-1-N,2-O-car-
bonyl-D-gluco-heptulose derivatives 23–27. In case of
O
HN
NH(CH2)4
O
OH
OBn
OH
HO
O
O
a
OH
OH
O
BnO
OBn
BnO
OH
5
11
Scheme 5. Reagents and condition: (a) Cbz-Lys-OH, EtOH, 10%.
O
OH
O
O
NR
OBn
O
NHR
a
BnO
BnO
OBn
OH
OH
7: R = Bn
8: R = (CH2)6OH
12: R = Bn
13: R = (CH2)6OH
9: R = (CH2)5COOMe
10: R = (CH2)4CH(NHCbz)COOH
14: R = (CH2)5COOMe
15: R = (CH2)4CH(NHCbz)COOH
Scheme 6. Reagents and conditions: (a) 1.6 equiv (CCl3O)2CO, >6 equiv Na2CO3, H2O, if necessary addition of 1,4-dioxane; yields for compounds
12–15: 12: 80%, 13: 30%, 14: 27%, 15: 65%.

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T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
HO
H
OH
O
HO
OH
OH
NR1R2
O
HO
HO
a - f
OH
HO
OH
OH
16
17: R1 = R2 = Bn
18: R1 = H, R2 = Bn
19: R1 = H, R2 = (CH2)6OH
20: R1 = H, R2 = (CH2)5COOMe
21: R1 = H, R2 = CH2COOBn
22: R1 = H, R2 = (CH2)4CH(NHCbz)COOH
Scheme 7. Reagents and conditions: (a) HNBn2, AcOH, EtOH, 93%; (b) H2NBn, AcOH, EtOH, 95%; (c) H2N(CH2)6OH, AcOH, EtOH, 80%; (d)
H2N(CH2)5COOMe, Et3N, EtOH, 82 %; (e) H2NCH2COOBn, Et3N, EtOH, 55%; (f) Cbz-Lys-OH, EtOH, 73%.
O
OH
O
O
HO
HO
NHR
a
NR
OH
O
HO
HO
OH
OH
OH
18: R = Bn
19: R = (CH2)6OH
23: R = Bn
24: R = (CH2)6OH
20: R = (CH2)5COOMe
21: R = CH2COOBn
25: R = (CH2)5COOMe
26: R = CH2COOH
22: R = (CH2)4CH(NHCbz)COOH
27: R = (CH2)4CH(NHCbz)COOH
Scheme 8. Reagents and conditions: (a) 1.6 equiv (CCl3O)2CO, >6 equiv Na2CO3, H2O; yields for compounds 23–27: 23: 60%, 24: 85%, 25: 60%, 26:
90%, 27: 26%.
Amadori product 21, under the fairly basic conditions
employed for carbamate formation the benzyl ester
was cleaved leading to free acid 26. Yields in almost
all examples were found in a satisfying range of 60–
90%, however compound 27 was isolated in only 36%
due to purification problems of this very polar com-
pound (Scheme 8).
gulo-heptose 16 was applied as a substrate, which allows
for synthesis of a carbohydrate amino acid conjugates
with D-gluco configuration in the sugar moiety, the
method worked nicely. With this commercially available
heptose, the rearrangement products were isolated in
very good yields in pure a-form. Investigations exploit-
ing various aldoses as starting materials to obtain differ-
ent configurations of the glycose moieties bound to
amino acids as well as fine tuning of the reaction condi-
tions in order to carry out the modification method in
physiological media are in progress.
In conclusion, we have developed a method for the
conjugation of carbohydrate moieties to amine func-
tions of amino acid derivatives employing the Amadori
rearrangement as the key step. The anomeric hydroxyl
function obtained during the rearrangement can, if nec-
essary, be stabilised by formation of a cyclic carbamate
between the anomeric hydroxyl group and the amine at
position C-1. By this procedure, C-glycosyl type glyco-
conjugates were obtained. In order to probe the reaction
conditions for the rearrangement as well as cyclic carba-
mate formation partly protected 3,5-di-O-benzyl-D-
glucofuranose 5 was chosen as a model substrate, how-
ever the yields obtained for the Amadori rearrangement
products turned out to be only moderate to low.
3. Experimental
3.1. General methods
NMR spectra were recorded on a Varian INOVA 500
operating at 500.619 MHz (1H), and at 125.894 MHz
(13C). CDCl3 was employed for the protected com-
pounds and methanol-d4 or D2O for free sugars.
Chemical shifts are listed in d employing residual, non-
deuterated solvent as the internal standard. Optical
rotations were measured on a Perkin Elmer 341 polar-
imeter at the wavelength of 589 nm and a path length
of 10 cm at 20 °C. Analytical TLC was performed on
5
2
Additionally, a/b anomic mixtures in the C2 and C5
conformation, respectively, were obtained. Obviously
the benzyl groups at positions 3 and 5 were not suitable
for favouring only the b-form in its 2C5 conformation as
expected. Contrary to these findings, when D-glycero-D-

T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
2061
precoated aluminium plates Silica Gel 60 F254 (E.
Merck 5554), detected with UV light (254 nm), 10% van-
illin/sulfuric acid as well as ceric ammonium molybdate
(100 g ammonium molybdate/8 g ceric sulfate in 1 L
10% H2SO4) and heated on a hotplate. Preparative
TLC was performed on precoated glass plates Silica
Gel 60 F254, 0.5 mm (E. Merck 5744). For column
chromatography Silica Gel 60 (230–400 mesh, E. Merck
9385) was used.
TLC showed conversion of the starting material. The
reaction was concentrated under diminished pressure
and the obtained compound mixture separated by flash
chromatography with the respective solvent mixture
indicated in Section 3.
3.6. 1-(N,N-Dibenzyl)amino-3,5-di-O-benzyl-1-deoxy-
a,b-D-fructopyranose (6)
Aldose 5 (1.0 g, 2.8 mmol) was reacted as described in
3.2. General method A (Amadori rearrangement with free
amines)
general method
A
with dibenzylamine (0.6 mL,
3.3 mmol, 1.2 equiv) and AcOH (0.2 mL, 3.3 mmol,
1.2 equiv) in EtOH (10 mL). After storage of the reac-
tion mixture in the fridge for 20 h compound 6 (1.0 g,
1.8 mmol, 71%) was isolated by filtration as an a/b-mix-
ture in a ratio of 1:3. 1H NMR (CDCl3): d 4.80 (d, 1H, J
12.2 Hz, OCH2Phb), 4.72 (d, 1H, J 11.2 Hz, OCH2Phb),
4.66 (d, 1H, J 12.2 Hz, OCH2Pha), 4.62 (d, 1H, J
12.2 Hz, OCH2Pha), 4.56 (d, 1H, J 11.7 Hz, OCH2Phb),
4.52 (d, 1H, J 11.7 Hz, OCH2Pha), 4.47 (d, 1H, J
11.2 Hz, OCH2Phb), 4.31 (d, 2H, J 11.7 Hz, OCH2Pha),
4.20 (m, 1H, H-5b), 4.13–4.10 (m, 6H, H-6eb, H-3a,
H-5a, H-6aa, NCH2Pha), 4.06 (m, 2H, H-6ab,
NCH2Pha), 3.98 (d, 2H, J 12.2 Hz, NCH2Phb), 3.64
(dd, 1H, J6a,6e 11.2 Hz, J6e,5 4.9 Hz, H-6ea), 3.51–3.47
(m, 3H, J4,5 4.4 Hz, J 13.7 Hz, H-4b, 2 ꢀ NCH2Phb),
3.35 (d, 1H, J 13.7 Hz, NCH2Pha), 3.26 (m, 1H,
The respective aldose was dissolved in abs EtOH,
approx. 1.2 equiv of the free amine and 1.2 equiv of
AcOH were added and the reaction was stirred at
40 °C until TLC showed satisfying conversion of the
starting material. The reaction mixture was concen-
trated under diminished pressure and the obtained
residue separated by flash chromatography with the
respective solvent system indicated in Section 3.
3.3. General method B (Amadori rearrangement with
amine hydrochlorides)
The respective amine hydrochloride was dissolved in abs
EtOH, 1 equiv of Et3N was added and the mixture
stirred for 20 min at rt. To this mixture the respective
aldose was added and the reaction stirred at 40 °C until
TLC showed satisfying conversion of the starting mate-
rial. The reaction mixture was concentrated under
diminished pressure and the product was purified by
flash chromatography with the respective solvent system
indicated in Section 3.
0
H-4a), 3.05 (dd, 1H, J1;1 13.7 Hz, H-1b), 2.82 (dd, 1H,
J1;1 13.7 Hz, H-1a), 2.63 (dd, 1H, H-10b), 2.46 (dd,
0
1H, H-10a). 13C NMR: d 98.0 (C-2b), 95.5 (C-2a),
79.4, 78.7 (2C, C-4a and b), 77.6, 77.4 (2C, C-3a and
b), 74.6, 72.9, 71.7, 71.0 (4C, 2ꢀOCH2Ph, a and b),
71.41 (2C, C-5a and b), 59.6 (C-6b), 57.8 (C-6a), 59.3
(2C, NCH2Ph); 57.3, 57.0 (2C, C-1a and b). Anal. Calcd
for C34H37NO5: C, 75.67; H, 6.91. Found: C, 75.62; H,
6.97.
3.4. General method C (Amadori rearrangement with
amino acid derivatives having a free carboxylic acid
residue)
3.7. 1-(N-Benzyl)amino-3,5-di-O-benzyl-1-deoxy-a,b-D-
fructopyranose (7)
The respective aldose was reacted in EtOH with the
amino acid derivative at 40–60 °C until TLC showed
satisfying conversion of the starting material. The reac-
tion mixture was concentrated under diminished pres-
sure and the obtained compound mixture purified by
flash chromatography with the respective solvent system
indicated in Section 3.
General method A was applied to aldose 5 (1.1 g,
3.0 mmol) using EtOH (15 mL), benzylamine (0.4 mL,
3.6 mmol, 1.2 equiv) and AcOH (0.2 mL, 3.7 mmol,
1.2 equiv). Silica gel chromatography with 1:2 cyclo-
hexane–EtOAc containing 1% of pyridine gave
compound 7 (751.0 mg, 1.7 mmol, 55%) as a yellow
oil. Compound 7 was difficult to purify and gave very
complex NMR spectra and was unambiguously charac-
terised by conversion into compound 12.
3.5. General method D (cyclic carbamate formation with
triphosgene)
The respective Amadori rearrangement product was dis-
solved in water, for better solubility 1,4-dioxane can be
added and a large excess of Na2CO3, typically >6 equiv,
was added at 0 °C. After 15 min triphosgene was added
and the reaction mixture stirred for 20 min at 0 °C
followed by stirring at room temperature (rt) until
3.8. 1-(N-6-Hydroxyhexyl)-amino-3,5-di-O-benzyl-1-
deoxy-a,b-D-fructopyranose (8)
General method A was applied to aldose 5 (1.2 g,
3.4 mmol), 6-aminohexanol (0.5 g, 4.1 mmol, 1.2 equiv)
and AcOH (0.23 mL, 4.1 mmol, 1.2 equiv) in EtOH

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T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
(15 mL). Silica gel chromatography (7:1 EtOAc–MeOH
containing 1% of concd NH3) gave compound 8 (0.8 g,
1.7 mmol, 52%) as a slightly yellow oil in an a/b ratio
of 1:4 determined by NMR. The b-anomer of
compound 8 was isolated after extensive silica gel
chromatography using 1:15 EtOAc–MeOH containing
0.5% of concd NH3. b-Anomer: [a]D ꢁ41.2 (c 2.4,
MeOH); 1H NMR (methanol-d4): d 4.97 (d, 1H, J
11.7 Hz, OCH2Ph), 4.69 (d, 1H, J 12.7 Hz, OCH2Ph),
4.67 (d, 1H, J 11.2 Hz, OCH2Ph), 4.66 (d, 1H, J
12.2 Hz, OCH2Ph), 4.57 (m, 1H, H-5), 4.07 (dd, 1H,
5.1 mmol, 1.5 equiv) in EtOH (10 mL). Silica gel chro-
matography (1:3 cyclohexane–EtOAc containing 1% of
concd NH3) gave compound 10 (252.5 mg, 0.5 mmol,
15%) as a slightly yellow oil in an a/b ratio of 1:3 deter-
mined by NMR. The b-anomer was isolated after exten-
sive silica gel chromatography using 2:1 cyclohexane–
EtOAc containing 0.5% of concd NH3. b-Anomer:
1
[a]D ꢁ15.9 (c 1.1, MeOH); H NMR (methanol-d4): d
5.12 (dd, 2H, J 12.2 Hz, COOCH2Ph), 4.93 (d, 1H, J
11.2 Hz, OCH2Ph), 4.68–4.62 (m, 3H, J 11.7 Hz, J
11.1 Hz, 3 ꢀ OCH2Ph), 4.54 (m, 1H, H-5), 4.06 (dd,
1H, J3,4 9.8 Hz, J4,5 3.4 Hz, H-4), 3.78 (d, 1H, H-6a),
3.70 (m, 2H, J6a,6e 12.2 Hz, H-6e, H-3), 3.37–3.34 (m,
0
J3,4 9.8 Hz, J4,5 3.4 Hz, H-4), 3.83 (d, 1H, J1;1 12.7 Hz,
H-1), 3.79–3.76 (m, 2H, J6a,6e 11.7 Hz, H-3, H-6a),
3.72 (m, 1H, H-6e), 3.56–3.51 (m, 3H, H-1, 2 ꢀ H-12),
3.32 (m, 1H, H-10), 2.51 (t, 2H, 2 ꢀ H-7), 1.51 (m, 2H,
H-9), 1.41 (m, 2H, 2 ꢀ H-8), 1.36–1.29 (m, 4H,
2 ꢀ H-11, 2 ꢀ H-10). 13C NMR: d 97.8 (C-2), 78.2,
78.0 (2C, C-3, C-4), 75.0 (OCH2Ph), 71.5 (C-5), 71.1
(OCH2Ph), 61.7 (2C, C-6, C-12), 59.9 (C-1), 49.7
(C-7), 32.4 (C-11), 29.5 (C-8), 27.0, 25.7 (2C, C-9,
C-10). Anal. Calcd for C26H37NO6: C, 67.95; H, 8.11.
Found: C, 67.91; H, 8.17.
2H, H-7), 2.70 (2 ꢀ d, 2H, J1;1 13.2 Hz, H-1, H-10).
0
13C NMR: d 98.2 (C-2), 78.1, 77.8 (2C, C-3, C-4),
75.1, 71.4, (2C, OCH2Ph), 71.0 (C-5), 66.2
(COOCH2Ph), 59.7 (C-6), 54.1 (C-1), 50.5 (C-7). Anal.
Calcd for C29H33NO7: C, 68.62; H, 6.55. Found: C,
68.58; H, 6.60.
3.11. 1-(N-(5S-Benzyloxycarbonyl)amino-6-carboxy-
pentyl)amino-3,5-di-O-benzyl-1-deoxy-b-D-fructopyra-
nose (11)
3.9. 1-(N-Methoxycarbonylpentyl)amino-3,5-di-O-
benzyl-1-deoxy-a,b-D-fructopyranose (9)
General method C was applied to compound 5 (1.5 g,
4.3 mmol) and Cbz-Lys-OH (1.4 g, 5.1 mmol,
1.2 equiv) in EtOH (15 mL). Crystallisation from
MeOH gave compound 11 (152.0 mg, 0.2 mmol, 10%)
of the pure b-anomer. [a]D ꢁ16.8 (c 1.1, DMF); 1H
NMR (DMSO-d6): d 4.98 (m, 2H, OCH2Ph), 4.89 (d,
1H, J 11.2 Hz, OCH2Ph), 4.64 (dd, 2H, J 12.7 Hz, J
13.2 Hz, OCH2Ph), 4.57 (d, 1H, J 9.7 Hz, OCH2Ph),
4.32 (m, 1H, H-5), 3.96 (dd, 1H, J3,4 9.8 Hz, H-4),
3.78 (d, 1H, H-11), 3.75 (d, 1H, J6a,6e 12.7 Hz, H-6a),
3.69 (d, 1H, H-6e), 3.54 (d, 1H, H-3), 2.98 (d, 1H,
Following General method B, 6-amino hexanoic acid
methyl ester hydrochloride (1.3 g, 7.1 mmol, 1,5 equiv)
was reacted in EtOH (10 mL) and Et3N (0.98 mL,
7.1 mmol, 1.5 equiv) with aldose 5 (1.7 g, 4.7 mmol).
Silica gel chromatography (5:1 EtOAc–MeOH contain-
ing 1% of concd NH3) gave compound 9 (0.6 g,
1.2 mmol, 25%) as a slightly yellow oil in an a/b ratio
of 1:2 determined by NMR. The b-anomer was isolated
after extensive silica gel chromatography using 15:1
EtOAc–MeOH containing 0.5% of concd NH3. b-Ano-
H-1), 2.82 (d, 1H, J1;1 12.7 Hz, H-10), 2.56 (m, 2H,
0
1
mer: [a]D ꢁ32.7 (c 3.2, MeOH); H NMR (methanol-
H-7), 1.60 (m, 2H, H-10), 1.48 (m, 2H, H-8), 1.24–
1.08 (m, 2H, H-9). 13C NMR: d 96.4 (C-2), 79.9,
78.5, 74.6 (3C, C-3, C-4, C-5), 71.7, 70.4, 65.9 (3C,
2 ꢀ CH2Ph, C-14), 61.2 (C-6), 55.4 (C-1), 54.2 (C-11),
49.0 (C-7), 30.7 (C-10), 25.4 (C-8), 21.5 (C-9). Anal.
Calcd for C34H42N2O9: C, 65.58; H, 6.80. Found: C,
65.52; H, 6.85.
d4): d 4.97 (d, 1H, J 11.7 Hz, OCH2Ph), 4.70–4.64
(m, 3H, 3 ꢀ OCH2Ph), 4.57 (m, 1H, H-5), 4.09–4.06
(m, 1H, J3,4 9.3 Hz, J4,5 4.4 Hz, H-4), 3.80–3.74 (m,
3H, H-3, H-6a, H-1), 3.76 (m, 1H, H-6e), 3.66 (m,
4H, OCH3, H-10), 3.32 (m, 2H, H-7), 2.50 (t, 2H, H-
11), 1.39 (d, 2H, H-8), 1.28–1.23 (m, 4H, H-9, H-10).
13C NMR: d 97.8 (C-2), 78.2, 78.0 (2C, C-3, C-4),
75.0, 71.1 (2C, 2 ꢀ OCH2Ph), 71.5 (C-5), 60.4 (C-6),
59.9 (C-1), 50.9 (OCH3), 49.4 (C-7), 33.6 (C-11), 29.1,
26.6, 24.7 (3C, C-8, C-9, C-10). Anal. Calcd for
C27H37NO7: C, 66.51; H, 7.65. Found: C, 66.46; H,
7.71.
3.12. 1-(N-Benzyl)amino-3,5-di-O-benzyl-1-N,2-O-
carbonyl-1-deoxy-a,b-D-fructopyranose (12)
General method D was applied to compound 7 (0.3 g,
0.6 mmol) in water and 1,4-dioxane (25 mL, 1/1 v/v),
Na2CO3 (390 mg, 3.7 mmol, 6.1 equiv) and triphosgene
(0.3 g, 1.0 mmol, 1.5 equiv). The reaction mixture was
concentrated under diminished pressure, diluted with
CH2Cl2, washed with 6% HCl and satd NaHCO3, dried
over Na2SO4 and concentrated again. Purification using
silica gel chromatography (1:1 cyclohexane–EtOAc con-
taining 1% of pyridine) gave compound 12 (231.0 mg,
3.10. 1-(N-Benzyloxycarbonylmethyl)amino-3,5-di-O-
benzyl-1-deoxy-a,b-D-fructopyranose (10)
General method B was applied to aldose 5 (1.2 g,
3.4 mmol) employing L-glycine benzyl ester hydrochlo-
ride (1.0 g, 5.1 mmol, 1.5 equiv), Et3N (0.7 mL,

T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
2063
0.5 mmol, 80%) in an a/b ratio of 1:1 as a slightly yellow
oil. Extensive purification gave analytical samples of the
two anomers. b-Anomer: [a]D ꢁ42.6 (c 1.0, CH2Cl2); 1H
NMR (CDCl3): d 4.89 (d, 1H, J 11.7 Hz, OCH2Ph), 4.66
(d, 1H, J 11.7 Hz, OCH2Ph), 4.52 (d, 1H, J 11.7 Hz,
OCH2Ph), 4.45 (d, 1H, J 11.7 Hz, OCH2Ph), 4.41 (d,
1H, H-4), 3.93 (dd, 2H, J6a,6e 13.2 Hz, H-6a, H-6e),
3.81 (m, 1H, H-5), 3.67 (d, 1H, J3,4 9.8 Hz, H-3), 3.56
0
(t, 2H, H-12), 3.41 (d, 1H, J1;1 9.3 Hz, H-1), 3.22 (d,
1H, H-10), 3.19 (t, 2H, H-7), 1.65 (m, 4H, H-8, H-11),
1.31, 1.19 (m, 4H, H-9, H-10). 13C NMR: d 156.4
(NCOO), 102.4 (C-2), 78.2 (C-3), 76.9 (C-4), 75.0, 72.1
(2C, OCH2Ph), 71.3 (C-5), 62.7, 62.1 (2C, C-6, C-12),
52.6 (C-1), 43.6 (C-7), 32.6 (C-11), 27.3, 26.2, 25.3 (3C,
C-9, C-10, C-11).
1H, J1;1 15.1 Hz, H-1), 4.22 (d, 1H, H-10), 4.11 (ddd,
0
1H, H-5), 3.89 (dd, 2H, J6a,6e 13.2 Hz, H-6a, H-6e),
3.73 (m, 1H, J4,5 3.4 Hz, H-4), 3.52 (d, 1H, J3,4 9.3 Hz,
0
H-3), 4.91 (d, 1H, J10;10 9.8 Hz, H-7), 3.07 (d, 1H,
H-70). 13C NMR: d 155.2 (NCOO), 101.2 (C-2), 76.5
(C-3), 75.5 (C-4), 73.6, 70.7 (2C, OCH2Ph), 70.1 (C-5),
60.7 (C-6), 51.0 (C-7), 46.7 (C-1). Anal. Calcd for
C28H29NO6: C, 70.72; H, 6.15. Found: C, 70.67; H,
3.14. 1-(N-Methoxycarbonylpentyl)-amino-3,5-di-O-
benzyl-1-N,2-O-carbonyl-1-deoxy-a,b-D-fructopyranose
(14)
1
6.19. a-Anomer: [a]D ꢁ5.8 (c 1.3, CH2Cl2); H NMR
General method D was applied to compound 9 (0.42 g,
0.9 mmol) in water and 1,4-dioxane (15 mL, 2/1 v/v),
Na2CO3 (0.9 g, 8.8 mmol, 10 equiv) and triphosgene
(0.42 g, 1.4 mmol, 1.5 equiv). Silica gel chromatography
(1:1 cyclohexane–EtOAc containing 0.5% of concd
NH3) gave compound 14 (0.12 g, 0.25 mmol, 27%) in
an a/b ratio of 1:1. Purification gave analytical samples
of the two anomers. a-Anomer: [a]D ꢁ17.1 (c 3.2,
(CDCl3): d 4.56 (d, 1H, J 11.7 Hz, OCH2Ph), 4.55 (d,
1H, J 12.2 Hz, OCH2Ph), 4.52 (d, 1H, J 12.2 Hz,
OCH2Ph), 4.42 (d, 1H, J 11.7 Hz, OCH2Ph), 4.32 (dd,
0
2H, J1;1 15.6 Hz, H-1), 4.01 (dd, 1H, J6a,6e 12.2 Hz,
J5,6a 8.8 Hz, H-6a), 3.94 (m, 1H, H-4), 3.74 (m, 1H,
H-5), 3.66 (d, 1H, J3,4 4.9 Hz, H-3), 3.52 (dd, 1H, J5,6e
0
3.9 Hz, H-6e), 3.23 (d, 1H, J10;10 10.3 Hz, H-7), 3.09
(d, 1H, H-7). 13C NMR: d 154.7 (NCOO), 99.9 (C-2),
76.6 (C-3), 72.9 (C-4), 70.4, 70.2 (2C, OCH2Ph), 66.0
(C-5) 60.2 (C-6), 52.5 (C-7), 44.8 (C-1).
CH2Cl2); H NMR (CDCl3): d 4.61 (d, 1H, J 11.2 Hz,
1
OCH2Ph), 4.54 (m, 2H, 2ꢀOCH2Ph), 4.64 (d, 1H, J
11.7 Hz, OCH2Ph), 4.06–3.99 (m, 2H, H-4, H-6e), 3.79
(m, 1H, H-5), 3.68 (br d, 1H, J3,4 4.39 Hz, H-3), 3.58
(s, 3H, OCH3), 3.55 (dd, 1H, J6a,6e 11.7 Hz, J5,6a
3.13. 1-(N-6-Hydroxyhexyl)amino-3,5-di-O-benzyl-1-
N,2-O-carbonyl-1-deoxy-a,b-D-fructopyranose (13)
0
4.4 Hz, H-6a), 3.3 (d, 1H, J1;1 10.2 Hz, H-1); 3.16 (d,
1H, H-10), 3.10 (m, 2H, H-7), 2.20 (t, 2H, H-11), 1.53,
1.37, 1.18 (m, 6H, H-8, H-9, H-10). 13C NMR: d 174.2
(COOMe), 155.8 (NCOO), 100.8 (C-2), 77.8 (C-3),
74.0, 71.6 (2C, OCH2Ph), 71.2 (C-5), 67.0 (C-4), 59.4
(C-6), 52.1 (C-1), 51.8 (OCH3), 43.7 (C-7), 34.0 (C-11),
27.1, 26.1, 24.7 (3C, C-8, C-9, C-10). Anal. Calcd for
C28H35NO8: C, 65.48; H, 6.87. Found: C, 65.42; H,
General method D was applied to compound 8 (0.6 g,
1.4 mmol) in water and 1,4-dioxane (24 mL, 2/1 v/v),
Na2CO3 (1.5 g, 13.8 mmol, 10 equiv) and triphosgene
(0.7 g, 2.2 mmol, 1.5 equiv). Silica gel chromatography
(1:1 cyclohexane–EtOAc containing 0.5% of concd
NH3) gave compound 13 (204.0 mg, 0.4 mmol, 30%) in
an a/b ratio of 1:4, purification gave analytical samples
of the two anomers. a-Anomer (48 mg, 0.1 mmol):
[a]Dꢁ8.5 (c 2.2, MeOH); 1H NMR (methanol-d4): d
4.88 (m, 1H, OCH2Ph), 4.74 (d, 1H, J 11.2 Hz,
OCH2Ph), 4.64 (m, 1H, OCH2Ph), 4.60 (d, 1H, J
11.2 Hz, OCH2Ph), 4.04 (dd, 1H, J6a,6e 12.2 Hz, J5,6a
5.9 Hz, H-6a), 3.95 (m, 1H, J4,5 2.5 Hz, H-4), 3.81 (d,
1H, J3,4 6.8 Hz, H-3), 3.76 (m, 1H, H-5), 3.63 (d, 1H,
1
6.91. b-Anomer: [a]D ꢁ63.4 (c 2.7, CH2Cl2); H NMR
(CDCl3): d 5.03 (d, 1H, J 11.7 Hz, OCH2Ph), 4.75 (d,
1H, J 11.7 Hz, OCH2Ph), 4.65 (d, 1H, J 11.7 Hz,
OCH2Ph), 4.55 (d, 1H, J 11.7 Hz, OCH2Ph), 4.15 (m,
1H, J4,5 9.3 Hz, H-4), 3.93 (dd, 2H, J6a,6e 13.2 Hz,
H-6a H-6e), 3.80 (m, 1H, H-5), 3.65 (d, 1H, J3,4
0
10.3 Hz, H-3), 3.64 (s, 3H, OCH3), 3.40 (d, 1H, J1;1
9.3 Hz, H-1), 3.21 (d, 1H, H-10), 3.17 (t, 2H, H-7),
2.22 (t, 2H, H-11), 1.57, 1.42, 1.24 (3 ꢀ m, 6H, H-8,
H-9, H-10). 13C NMR: d 174.2 (COOMe), 156.3
(NCOO), 102.3 (C-2), 78.2 (C-3), 76.8 (C-5), 75.0, 72.0
(2C, OCH2Ph), 68.3 (C-4), 62.1 (C-6), 52.6 (C-1), 51.8
(OCH3), 43.6 (C-7), 34.0 (C-11), 27.2, 26.2, 24.7 (3C,
C-8, C-9, C-10).
J1;1 10.3 Hz, H-10), 3.60 (dd, 1H, J5,6e 2.4 Hz, H-6e),
0
3.50 (t, 2H, H-12), 3.36 (d, 1H, H-1), 3.20 (m, 2H,
H-7), 1.46 (m, 4H, H-8, H-11), 1.32, 1.23 (2 ꢀ m, 4H,
H-9, H-10). 13C NMR: d 157.0 (NCOO), 102.6 (C-2),
78.7 (C-3), 74.5 (OCH2Ph), 73.4 (C-5), 71.2 (OCH2Ph),
68.2 (C-4), 61.7 (C-12), 60.3 (C-6), 48.7 (C-1), 43.3
(C-7), 32.3 (C-11), 26.9, 26.1, 25.3 (3C, C-9, C-10,
C-11). Anal. Calcd for C27H35NO7: C, 66.79; H, 7.27.
Found: C, 66.73; H, 7.32. b-Anomer (70.7 mg,
0.15 mmol): [a]D ꢁ80.9 (c 2.3, CH2Cl2); 1H NMR
(CDCl3): d 5.04 (d, 1H, J 11.7 Hz, OCH2Ph), 4.75 (d,
1H, J 11.7 Hz, OCH2Ph), 4.66 (d, 1H, J 12.2 Hz,
OCH2Ph), 4.56 (d, 1H, J 11.7 Hz, OCH2Ph), 4.16 (m,
3.15. 1-(N-(5S-Benzyloxycarbonyl)amino-6-carboxy-
pentyl)-amino-3,5-di-O-benzyl-1-N,2-O-carbonyl-1-
deoxy-b-D-fructopyranose (15)
General method D was applied to compound 11 (0.1 g,
0.2 mmol) in water and 1,4-dioxane (10 mL, 1/1 v/v),

2064
T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
Na2CO3 (0.4 g, 3.6 mmol, 16 equiv) and triphosgene
(0.11 g, 0.4 mmol, 1.7 equiv). Compound 15 (95.3 mg,
0.2 mmol, 65%) was obtained in the pure b form by silica
gel chromatography (3:1 EtOAc–MeOH containing 0.2%
of concd NH3). Compound 15 was not soluble in any
common solvent, no optical rotation could be measured.
1H NMR (DMSO-d6): d 5.00 (m, 2H, OCH2Ph), 4.93 (d,
1H, J 11.2 Hz, OCH2Ph), 4.66 (m, 2H, J 9.3 Hz, J 9.8 Hz,
OCH2Ph), 4.57 (m, 1H, J 10.2 Hz, OCH2Ph), 3.90–3.82
(C-2), 74.4 (C-4), 73.3 (C-3), 73.0 (C-5), 70.4 (C-6),
61.6 (C-7), 53.9 (C-1), 53.1 (NHCH2Ph). Anal. Calcd
for C14H21NO6: C, 56.18; H, 7.07. Found: C, 56.15;
H, 7.10.
3.18. 1-(N-6-Hydroxyhexyl)amino-1-deoxy-a-D-gluco-
hept-2-ulopyranose (19)
General method A was applied to aldose 16 (210.4 mg,
1.0 mmol) in EtOH (10 mL), 6-aminohexanol
(155.0 mg, 1.3 mmol, 1.3 equiv) and AcOH (80.0 lL,
1.3 mmol, 1.3 equiv). Silica gel chromatography (6:1
chloroform–MeOH containing 1% of concd NH3) gave
compound 19 (245.4 mg, 0.8 mmol, 80%) as a slightly
0
(m, 3H, H-1, H-4, H-6a), 3.97 (dd, 2H, J1;1 13.7 Hz,
J6a,6e 10.3 Hz, H-10, H-6e), 3.49 (m, 1H, H-11), 3.38 (m,
1H, H-5), 3.22 (d, 1H, J3,4 9.8 Hz, H-3), 3.00 (m, 2H,
H-7), 1.65, 1.52 (m, 6H, H-8, H-9, H-10). 13C NMR: d
163.0 (COOH), 156.8, 156.1 (2C, NCOO, NHCOOBn),
102.8 (C-2), 78.1, 77.8 (2C, C-3, C-5), 74.9 (OCH2Ph),
71.8 (C-4), 71.0 (OCH2Ph), 66.0 (C-14), 63.4 (C-6), 54.4
(C-1), 52.7 (C-11), 51.8 (C-7), 31.8 (C-10), 24.5 (C-8),
22.9 (C-9). Anal. Calcd for C35H40N2O10: C, 64.80; H,
6.22. Found: C, 64.75; H, 6.28.
1
orange oil. [a]D +38.3 (c 3.7, MeOH); H NMR (meth-
0
anol-d4): d 3.82 (dd, 1H, J7;7 11.7 Hz, J6,7 1.5 Hz, H-7),
0
3.75–3.71 (m, 1H, H-6), 3.70–3.66 (m, 2H, J6;7 5.4 Hz,
J3,4 9.3 Hz, H-4, H-70), 3.55 (t, 2H, H-13), 3.32–3.28
(m 2H, J5,4=5,6 9.3 Hz, H-3, H-5), 3.03–3.00 (n.d., 2H,
H-1, H-10), 2.89–2.79 (m, 2H, H-8), 1.65–1.63 (m, 2H,
H-9), 1.56–1.53 (m, 2H, H-12), 1.40–1.39 (m, 4H,
H-10, H-11). 13C NMR: d 95.9 (C-2), 74.2 (C-4), 73.4
(C-3), 73.2 (C-6), 70.4 (C-5), 61.6 (C-13), 61.5 (C-7),
54.1 (C-1), 49.1 (C-8), 32.3 (C-12), 27.4 (C-9), 26.6,
25.5 (2C, C-10, C-11). Anal. Calcd for C13H27NO7: C,
50.47; H, 8.80. Found: C, 50.44; H, 8.84.
3.16. 1-(N,N-Dibenzyl)amino-1-deoxy-a-D-gluco-hept-2-
ulopyranose (17)
Heptose 16 (115.1 mg, 0.6 mmol) was reacted as
described in general method A with dibenzylamine
(0.13 mL, 0.7 mmol, 1.2 equiv) and AcOH (40.0 lL,
0.7 mmol, 1.2 equiv) in EtOH (8 mL). Silica gel chromato-
graphy (1:2 cyclohexane–EtOAc) gave compound 17
(200 mg, 0.5 mmol, 93%) as a white precipitate. [a]D
3.19. 1-(N-Methoxycarbonylpentyl)amino-1-deoxy-a-D-
gluco-hept-2-ulopyranose (20)
1
1
+45.4 (c 1.2, MeOH); H NMR (CDCl3): d H NMR
(CDCl3): d 3.97 (d, 2H, J 13.2 Hz, NCH2Ph), 3.75–
Following general method B, 6-amino hexanoic acid
methyl ester hydrochloride (290.0 mg, 1.6 mmol,
1.6 equiv) in EtOH (8 mL) and Et3N (225.0 lL,
1.6 mmol, 1.6 equiv) was applied to aldose 16
(207.2 mg, 1.0 mmol). Silica gel chromatography (4:1
chloroform–MeOH containing 1% of concd NH3) gave
compound 20 (272 mg, 0.8 mmol, 82%) as a yellow oil.
0
3.67 (m, 3H, H-4, H-7, H-6), 3.62 (d, 1H, J6;7 7.7 Hz,
H-70), 3.50 (d, 2H, J 13.2 Hz, NCH2Ph), 3.47 (dd, 1H,
J5,4 8.3 Hz, J5,6 9.3 Hz, H-5), 3.12 (d, 1H, J3,2 9.3 Hz,
0
H-3), 0.02 (d, 1H, J1;1 13.2 Hz, H-1), 2.67 (d, 1H,
H-10). 13C NMR: d 97.0 (C-2), 75.1 (C-4), 73.3 (C-3),
72.1 (C-6), 70.3 (C-5), 62.2 (C-7), 59.0 (2C, NCH2Ph),
57.2 (C-1). Anal. Calcd for C21H27NO6: C, 64.77; H,
6.99. Found: C, 64.73; H, 7.04.
1
[a]D +31.1 (c 4.0, MeOH); H NMR (methanol-d4): d
0
3.45 (dd, 1H, J6,7 1.0 Hz, J7;7 11.2 Hz, H-7), 3.77–3.74
0
(m, 1H, H-6), 3.70–3.66 (m, 2H, J6;7 4.9 Hz, H-4,
3.17. 1-(N-Benzyl)amino-1-deoxy-a-D-gluco-hept-2-ulo-
pyranose (18)
H-70), 3.65 (s, 3H, OCH3), 3.33 (d, 1H, J3,4 9.3 Hz, H-
3), 3.30 (dd, 1H, J5,4 9.8 Hz, J5,6 7.3 Hz, H-5), 3.22 (d,
1H, J1;1 12.7 Hz, H-1), 3.17 (d, 1H, H-10), 3.02 (br t,
0
Heptose 16 (251.6 mg, 1.2 mmol) was reacted as
described in general method A with benzylamine
(0.17 mL, 1.6 mmol, 1.3 equiv) and AcOH (100.0 lL,
1.6 mmol, 1.3 equiv) in EtOH (10 mL). Silica gel chro-
matography (5:1 chloroform–MeOH containing 1% of
concd NH3) gave compound 18 (341.0 mg, 1.1 mmol,
95%) as a slightly yellow oil. [a]D +37.3 (c 0.5, MeOH);
1H NMR (methanol-d4): d 4.16 (d, 1H, J 12.5 Hz,
2H, H-8), 2.36 (t, 2H, H-12), 1.73 (q, 2H, H-11), 1.66
(q, 2H, H-9), 1.41 (q, 2H, H-10). 13C NMR: d 174.5
(C-13), 95.1 (C-2), 74.0 (C-4), 73.5 (C-6), 73.4 (C-3),
70.3 (C-5), 61.3 (C-7), 53.3 (C-1), 50.9 (OCH3), 48.3
(C-8), 33.2 (C-12), 26.0 (C-10), 25.5 (C-11), 24.2 (C-9).
Anal. Calcd for C14H27NO8: C, 49.84; H, 8.07. Found:
C, 49.79; H, 8.09.
0
NCH2Ph), 4.13 (d, 1H, NCH2Ph), 3.83 (d, 1H, J7;7
3.20. 1-(N-Benzyloxycarbonylmethyl)amino-1-deoxy-a-
D-gluco-hept-2-ulopyranose (21)
11.2 Hz, H-7), 3.76–3.73 (m, 1H, H-6), 3.69–3.65
(m, 2H, J3,4 9.3 Hz, J4,5 7.3 Hz, H-4, H-70), 3.31–3.28
0
(m, 2H, J5,6 9.8 Hz, H-3, H-5), 3.10 (d, 1H, J1;1
General method B was applied to L-glycine benzyl ester
hydrochloride (440 mg, 2.2 mmol, 1.5 equiv) in EtOH
12.2 Hz, H-1), 3.05 (d, 1H, H-1). 13C NMR: d 96.6

T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
2065
(8 mL), Et3N (215.0 lL, 1.5 mmol, 1.0 equiv) and hep-
3.23. 1-(N-6-Hydroxyhexyl)amino-1-N,2-O-carbonyl-1-
deoxy-a-D-gluco-hept-2-ulopyranose (24)
tose 16 (300.0 mg, 1.4 mmol). Silica gel chromatography
(6:1 chloroform–MeOH containing 1% of concd NH3)
gave compound 21 (275 mg, 0.8 mmol, 55%) as a yellow
General method D was applied to compound 19
(148.5 mg, 0.5 mmol), Na2CO3 (560 mg, 5.3 mmol,
6.1 equiv) and triphosgene (260 mg, 0.9 mmol,
1.8 equiv) in water (5 mL). Silica gel chromatography
(6:1 chloroform–MeOH containing 1% of concd NH3)
gave compound 24 (136 mg, 0.4 mmol, 85%) as a slightly
1
oil. [a]D +35.8 (c 2.5, MeOH); H NMR (methanol-d4):
0
d 5.19 (br s, 2H, OCH2Ph), 3.79 (br d, 1H, J7;7 10.7 Hz,
H-7), 3.74–3.71 (m, 1H, H-6), 3.69–3.61 (m, 4H, H-4,
H-70, H-8), 3.32–3.29 (m, 2H, H-3, H-5), 2.94 (bs, 2H,
H-1, H-10). 13C NMR: d 171.4 (C-9), 96.6 (C-2), 74.4
(C-4), 73.1 (C-3), 73.0 (C-6), 70.5 (C-5), 66.3 (C-10),
61.6 (C-7), 54.2 (C-1), 49.9 (C-8). Anal. Calcd for
C16H23NO8: C, 53.78; H, 6.49. Found: C, 53.75; H,
6.52.
1
yellow precipitate. [a]D +51.5 (c 4.4, MeOH); H NMR
0
(methanol-d4): d 3.82–3.79 (m, 2H, J7;7 9.7 Hz, H-1, H-
7), 3.74–3.72 (m, 2H, H-6, H-70), 3.65 (dd, 1H, J3,4
9.3 Hz, J4,5 9.8 Hz, H-4), 3.54 (t, 2H, H-13), 3.45 (d,
0
1H, H-3), 3.43 (dd, J5,6 8.8 Hz, H-5), 3.39 (d, 1H, J1;1
3.21. 1-(N-(5S-Benzyloxycarbonyl)amino-6-carboxy-
pentyl)amino-1-deoxy-a-D-gluco-hept-2-ulopyranose
(22)
9.8 Hz, H-10), 3.30–3.24 (m, 2H, H-8), 1.63–1.50 (m,
4H, H-11, H-12), 1.48–1.23 (m, 4H, H-9, H-10). 13C
NMR: d 157.3 (NCOO), 102.9 (C-2), 75.7 (C-6), 74.1
(C-4), 72.7 (C-3), 69.6 (C-5), 61.7 (C-13), 60.9 (C-7),
52.1 (C-1), 43.3 (C-8), 32.3 (C-12), 26.9, 26.1, 25.3 (3C,
C-9, C-10, C-11). Anal. Calcd for C14H25NO8: C,
50.14; H, 7.51. Found: C, 50.09; H, 7.55.
General method C was applied to heptose 16 (233.0 mg,
1.1 mmol) and Cbz-Lys-OH (500.0 mg, 1.7 mmol,
1.6 equiv) in EtOH (6 mL). Silica gel chromatography
(3:1 chloroform–MeOH containing 1% of concd NH3)
gave compound 22 (393.1 mg, 0.8 mmol, 73%) as a yel-
low oil. [a]D +41.5 (c 1.3, water); 1H NMR (D2O): d 4.8
(d, 1H J 12.2 Hz, H-15), 4.74 (d, 1H, H-15), 3.70–3.68
3.24. 1-(N-Methoxycarbonylentyl)-amino-1-N,2-O-
carbonyl-1-deoxy-a-D-gluco-hept-2-ulopyranose (25)
(m, 2H, H-7, H-12), 3.63 (m, 1H, J7;7 11.8 Hz, H-70),
General method D was applied to compound 20
(198.2 mg, 0.6 mmol), Na2CO3 (690.0 mg, 6.5 mmol,
6.1 equiv) and triphosgene (320 mg, 1.1 mmol,
1.8 equiv) in water and 1,4-dioxane (8 mL, 1/1 v/v). Sil-
ica gel chromatography (6:1 chloroform–MeOH con-
taining 1% of concd NH3) gave compound 25
(129.0 mg, 0.4 mmol, 60%) as a yellow oil. [a]D +55.5
(c 3.4, MeOH); 1H NMR (methanol-d4): d 3.81–3.78
0
3.57–3.50 (m, 1H, H-6), 3.51 (dd, 1H, J4,5 8.3 Hz, J3,4
9.3 Hz, H-4), 3.21 (dd, 1H, J5,6 8.8 Hz, H-5), 3.18 (d,
0
1H, H-3), 2.97–2.92 (2 ꢀ br d, 2H, J1;1 12.7 Hz, H-1,
H-10), 2.71–2.63 (m, 2H, H-8), 1.53–1.50 (m, 1H,
H-11), 1.43–1.32 (m, 3H, 2 ꢀ H-9, H-11), 1.10–1.07
(m, 2H, H-10). 13C NMR: d 179.6 (C-13), 157.7
(C-14), 95.1 (C-2), 73.3 (C-4), 72.8 (C-3), 72.6 (C-6),
69.4 (C-5), 66.8 (C-15), 60.7 (C-7), 56.2 (C-12), 49.0
(C-1), 39.3 (C-8), 31.4 (C-11), 26.5 (C-9), 22.2 (C-10).
Anal. Calcd for C21H32N2O10: C, 53.38; H, 6.83. Found:
C, 53.34; H, 6.86.
0
(m, 2H, J7;7 10.3 Hz, H-1, H-7), 3.75–3.70 (m, 2H, H-
6, H-70), 3.65 (m, 4H, J4,5 10.8 Hz, H-4, OCH3), 3.44–
3.40 (m, 2H, J1;1 9.8 Hz, J5,6 9.8 Hz, H-10, H-5), 3.35
0
(d, 1H, J3,4 9.8 Hz, H-3), 3.30–3.24 (m, 2H, H-8), 2.30
(t, 2H, H-12), 1.64 (q, 2H, H-11), 1.58 (q, 2H, H-10),
1.34 (q, 2H, H-9). 13C NMR: d 174.8 (C-13), 157,3
(NCOO), 102.9 (C-2), 75.7 (C-6), 74.1 (C-4), 72.7 (C-
3), 69.6 (C-5), 60.9 (C-7), 52.0 (C-1), 51.0 (OCH3),
43.1 (C-8), 33.5 (C-12), 26.6 (C-10), 25.7 (C-9), 24.4
(C-11). Anal. Calcd for C15H25NO9: C, 49.58; H, 6.93.
Found: C, 49.55; H, 6.95.
3.22. 1-(N-Benzyl)amino-1-N,2-O-carbonyl-1-deoxy-a-D-
gluco-hept-2-ulopyranose (23)
General method D was applied to compound 18
(313.6 mg, 1.1 mmol), Na2CO3 (690 mg, 6.5 mmol,
6.0 equiv) and triphosgene (320 mg, 1.1 mmol,
1.0 equiv) in water (8 mL). Silica gel chromatography
(6:1 chloroform–MeOH containing 1% of concd NH3)
gave compound 23 (205.2 mg, 0.6 mmol, 60%) as a
slightly yellow precipitate. [a]D +56.3 (c 4.2, MeOH);
1H NMR (methanol-d4): d 4.49 (d, 1H, J 15.6 Hz,
NCH2Ph), 4.41 (d, 1H, NCH2Ph), 3.81–3.67 (m, 5H,
H-1, H-4, H-6, H-7, H-70), 3.44 (dd, 1H, J5,3=5,4
9.3 Hz, H-5), 3.34–3.31 (m, 2H, H-10, H-3). 13C NMR:
d 157.4 (C-8), 103.1 (C-2), 75.8 (C-4), 74.1 (C-6), 72.7
(C-3), 69.5 (C-5), 60.8 (C-7), 51.9 (C-1), 47.3 (C-9).
Anal. Calcd for C15H19NO7: C, 55.38; H, 5.89. Found:
C, 55.36; H, 5.91.
3.25. 1-(N-Methoxycarbonylpentyl)amino-1-N,2-O-
carbonyl-1-deoxy-a-D-gluco-hept-2-ulopyranose (26)
General method D was applied to compound 21
(226.5 mg, 0.6 mmol), Na2CO3 (660.0 mg, 6.2 mmol,
6.1 equiv) and triphosgene (300.0 mg, 1.0 mmol,
1.6 equiv) in water (5 mL). Silica gel chromatography
(1:2 chloroform–MeOH containing 1% of concd NH3)
gave compound 26 (160.0 mg, 0.6 mmol, 90%) as a yel-
low oil. [a]D +49.8 (c 1.7, water); 1H NMR (D2O): d 3.93
0
(d, 1H, J1;1 10.7 Hz, H-1), 3.90–3.79 (m, 4H, H-6, H-7,

2066
T. M. Wrodnigg et al. / Carbohydrate Research 343 (2008) 2057–2066
H-8), 3.75 (dd, 1H, J6;7 5.4 Hz, J7;7 12.2 Hz, H-70), 3.73
(dd, 1H, H-4), 3.61 (d, 1H, J3,4 9.8 Hz, H-3), 3.56 (d, 1H,
H-10), 3.52 (dd, 1H, J4,5 9.3 Hz, J5,6 9.8 Hz, H-5). 13C
NMR: d 175.3 (COOH), 158.2 (NCOO), 103.3 (C-2),
75.1 (C-6), 73.6 (C-4), 71.9 (C-3), 69.1 (C-5), 60.7
(C-7), 53.4 (C-1), 47.1 (C-8). Anal. Calcd for
C10H15NO9: C, 40.96; H, 5.16. Found: C, 40.92; H, 5.19.
0
0
Bolanos, J. G.; Ulgar, V.; Maya, I.; Fuentes, J.; Dianez,
M. J.; Estrada, M. D.; Lopez-Castro, A.; Perez-Garrido,
S. Tetrahedron: Asymmetry 2003, 14, 1009–1018; (c)
Kadokawa, J.; Hino, D.; Karasu, M.; Tagaya, H.; Chiba,
K. Eur. Polym. J. 2000, 36, 225–230; (d) Shu, L.; Shen,
Y.-M.; Burke, C.; Goeddl, D.; Shi, Y. J. Org. Chem. 2003,
68, 4963–4965.
5. (a) Peri, F. Mini-Rev. Med. Chem. 2003, 3, 651–658; (b)
Leeuwenburgh, M. A.; van der Marel, G. A.; Overkleeft,
H. S. Curr. Opin. Chem. Biol. 2003, 7, 757–765; (c) Mellet,
C. O.; Defaye, J.; Garcia Fernandez, J. M. Biol. Zhurnal
Armenii 2001, 53, 70–81; (d) Roy, R. In Carbohydrate
Chemistry; Boons, G.-J., Ed.; Blackie, 1998; pp 243–321;
(e) Pachamuthu, K.; Schmidt, R. R. Chem. Rev. 2006, 106,
160–187.
3.26. 1-(N-5S-Benzyloxycarbonylamino-6-carboxy-
pentyl)amino-1-N,2-O-carbonyl-1-deoxy-a-D-gluco-hept-
2-ulopyranose (27)
General method D was applied to compound 22
(226.7 mg, 0.6 mmol), Na2CO3 (600.0 mg, 5.7 mmol,
6.3 equiv) and triphosgene (260.0 mg, 0.9 mmol,
1.6 equiv) in water (5 mL). Silica gel chromatography
(5:1 chloroform–MeOH containing 1% of concd NH3)
gave compound 28 (101 mg, 0.2 mmol, 36%) as a yellow
oil. [a]D +54.2 (c 0.5, water); 1H NMR (D2O): d 4.96 (d,
1H, J 12.2 Hz, H-15), 4.56 (d, 1H, H-15), 3.76 (m, 1H,
H-12), 3.66–3.59 (m, 2H, H-1, H-7. H-70), 3.59–3-57
6. (a) Varki, A. Essentials of Glycobiology; Cold Spring
Harbor Laboratory Press: New York, 1999; (b) Varki, A.
Glycobiology 1993, 3, 97–130; (c) Kamiya, Y.; Kato, K.
Trends Glycosci. Glycotechnol. 2006, 18, 231–244.
7. Hashimoto, T.; Nomoto, M.; Komatsu, K.; Haga, M.;
Hayashi, M. Eur. J. Pharm. Biopharm. 2000, 50, 197–
204.
8. (a) Buskas, T.; Ingale, S.; Boons, G.-J. Glycobiology 2006,
16, 113R–136R; (b) Pratt, M. R.; Bertozzi, C. R. Chem.
Soc. Rev. 2005, 34, 58–68; (c) Davis, B. G. Chem. Rev.
2002, 102, 579–601; (d) Guo, Z.; Shao, N. Med. Res. Rev.
2005, 25, 655–678.
0
(m, 1H, J6;7 6.4 Hz, H-6), 3.55 (dd, 1H, J3,4=4,5
9.8 Hz, H-4), 3.36–3.32 (m, 2H, J5,4 6.8 Hz, H-3, H-5),
9. (a) Brik, A.; Wong, C.-H. Chem.-Eur. J. 2007, 13, 5670–
5675; (b) Hojo, H.; Nakahara, Y. Biopolymers 2007, 88,
308–324; (c) Macmillan, D. Angew. Chem., Int. Ed. 2006,
45, 7668–7672; (d) Mogemark, M.; Kihlberg, J. In The
3.27 (d, 1H, J1;1 10.3 Hz, H-10), 3.09–2.97 (m, 2H,
0
H-8), 1.63–1.54; 1.50–1.42 (2m, 2H, H-11), 1.40–1.30
(m, 2H, H-9), 1.16–1.06 (m, 2H, H-10. 13C NMR: d
179.8 (COOH), 157.9, 157.8 (2C, C-14, C-16), 103.1
(C-2), 74.9 (C-6), 73.4 (C-4), 71.9 (C-3), 68.9 (C-5),
67.0 (OCH2Ph), 60.3 (C-7), 56.2 (C-12), 52.0 (C-1),
43.2 (C-8), 31.2 (C-11), 25.8 (C-9), 22.2 (C-10). Anal.
Calcd for C22H30N2O11 C, 53.01; H, 6.07. Found: C,
52.98; H, 6.11.
Organic Chemistry of Sugars; Levy, P. E., Fugedi, P., Eds.;
¨
CRC Press: Taylor and Francis, 2006; pp 755–801.
10. (a) Murata, T.; Usui, T. Biosci. Biotechnol. Biochem. 2006,
70, 1049–1059; (b) Seibel, J.; Joerdening, H.-J.; Buchholz,
K. Biocatal. Biotransform. 2006, 24, 311–342; (c) Liu, L.;
Bennett, C. S.; Wong, C.-H. Chem. Commun. 2006, 1, 21–
33.
11. (a) Taylor, R. J. K.; McAllister, G. D.; Franck, R. W.
Carbohydr. Res. 2006, 341, 1298–1311; (b) Dondoni, A.;
Massi, A. Acc. Chem. Res. 2006, 39, 451–463; (c) Micova,
J.; Steiner, B.; Koos, M.; Langer, V.; Gyepesova, D.
Carbohydr. Res. 2004, 339, 2187–2195; (d) Postema, M. H.
D.; Piper, J. L. Org. Lett. 2003, 5, 1721–1723; (e) Walter,
A.; Westermann, B. Synlett 2000, 1682–1684.
12. (a) Doores, K. J.; Gamblin, D. P.; Davis, B. G. Chem.-
Eur. J. 2006, 12, 656–665; (b) Liakatos, A.; Kunz, H. Curr.
Opin. Mol. Ther. 2007, 9, 35–44; (c) Freire, T.; Bay, S.;
Vichier-Guerre, S.; Lo-Man, R.; Leclerc, C. Mini-Rev.
Med. Chem. 2006, 6, 1357–1373; (d) Van Bambeke, F.
Curr. Opin. Invest. Drugs 2006, 7, 740–749; (e) Becker, T.;
Dziadek, S.; Wittrock, S.; Kunz, H. Curr. Cancer Drug
Targets 2006, 6, 491–517; (f) Bryskier, A.; Veyssier, P.
Antimicrob. Agents Chemother. 2005, 880–905.
Acknowledgement
Financial support by the Austrian Fonds zur Fo¨rderung
der Wissenschaftlichen Forschung (FWF), Vienna,
(Project P18998-N17) is gratefully acknowledged.
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