Preparation of macrocyclic15N-labelled oligoaminodeoxysaccharides as probes for RNA-binding

Article abstract of DOI:10.1039/b412436g

Two macrocyclic aminoglycosides were prepared from a 1,4-butanediol linked 2-deoxy-L-rhamnal which was O-allylated at the 4- and 4'-positions via the precursor allyl 3,4-di-O-acetyl-2,6-dideoxy-α-L-arabino-hexoside employing olefin metathesis and ring clo

Full text of DOI:10.1039/b412436g

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A R T I C L E
Preparation of macrocyclic 15N-labelled
oligoaminodeoxysaccharides as probes for RNA-binding
Janis Jaunzems, Benjamin Oelze and Andreas Kirschning*
Institut fu¨r Organische Chemie der Universita¨t Hannover, Schneiderberg 1B, D-30167,
Hannover, Germany. E-mail: andreas.kirschning@oci.uni-hannover.de
Received 13th August 2004, Accepted 7th October 2004
First published as an Advance Article on the web 10th November 2004
Two macrocyclic aminoglycosides were prepared from a 1,4-butanediol linked 2-deoxy-L-rhamnal which was
O-allylated at the 4- and 4ꢀ-positions via the precursor allyl 3,4-di-O-acetyl-2,6-dideoxy-a-L-arabino-hexoside
employing olefin metathesis and ring closing metathesis in a sequential manner. The macrocycles were 15N-labelled at
all four amino groups in order to study interactions with regulatory RNA structures in solution by NMR
spectroscopy. A key step for the introduction of the 15N-label was a reductive amination step using commercially
available 15NH4OAc. The reductive amination proceeds with excellent stereocontrol. As a by-product the unusual
acyclic amino nitrile was isolated which originated from intramolecular imine formation followed by cyanide
addition to the intermediate C=N double bond.
proved antibacterial performance whilst targeting resistance-
Introduction
causing enzymes at the same time.9
Small-molecule natural products and natural product-like ana-
Recently, we described the first preparation of a novel macro-
logues have aided understanding of the role and function
of many biomacromolecules critical to the progression and
cyclic 1,4-butanediol-linked aminodeoxyglycoside 2 (Fig. 1).10
The coupling of the aminodeoxyhexose units was achieved
maintenance of the cell cycle. Successfully identifying the direct
by olefin metathesis of appropriately allylated aminosugar
target of a particular molecule provides a tool with which to
precursors and then by ring-closing metathesis.11 In addition,
control specific aspects of the cell cycle.1 In this context, RNA
has been regarded as a particularly important macromolecule,
since it exhibits a great functional and structural variety,
we conducted competitive dot blot binding experiments with
TAR-RNA and the Tat protein in the presence of macrocycle 2.
Furthermore, two aptamers selected for binding to the REV pro-
comparable to that of proteins. The vast conformational range
tein were included in these affinity studies. These investigations
of RNA should allow for specific binding by small molecules.
Recently, the effort of many research groups was dedicated to
revealed that unlike other butanediol linked neoaminoglycosides
obtained from allylated aminohexoses, macrocycle 2 is able to
the synthesis of molecules that are able to selectively bind to
inhibit the TAR-RNA–Tat-protein interaction.12 In order to
RNA.1 Among the various ligands that have been considered
obtain a deeper understanding of the nature and mode of bind-
ing, we planned to study the complex in solution, formed upon
mixing the TAR-RNA with macrocycle 2 by NMR spectroscopy.
for this task,2 aminoglycosides such as neomycin B (1) are the
most promising substructures (Fig. 1).3a–c In this context, the
interactions between aminoglycosides and various RNA targets,
Our original synthetic strategy had one major drawback
including the HIV-1 TAR-RNA used in competitive binding
in view, that the NMR experiments required the 15N-labelled
studies in the presence of the Tat protein, have been studied by
aminoglycoside analogue for localizing proximities between
functional groups and structural elements of the RNA and the
various groups.3–8
aminoglycoside 2. The 15N-labelled aminoglycosides will only
be conveniently accessible if the nitrogen label is introduced at a
late stage of the synthesis and a readily available 15N source can
be utilized. We reckoned that the successful introduction of a
15N-labelled amino group into complex glycosides should be of
general utility in the context of aminoglycosides and binding
studies to nucleic acids in solution. Here, we report on the
efficient synthesis of labelled macrocycle [15N]-2 by an alternate
route to that previously reported.
Results and discussion
At first, we had to design a new synthetic route which allowed
introduction of the 15N label at a late stage. Thus, L-rhamnal
Fig. 1 Structures of the aminoglycoside neomycin B (1) and macrocycle
2.
5 was chosen as a starting point for the preparation of the
target macrocycle [15N]-2 (Scheme 1). Polymer-bound triphenyl
The results of those studies suggest that particular RNA
regions containing either asymmetric internal loops or hairpin
loop–stem junctions are preferential binding sites for amino-
glycosides. Indeed, their basic scaffold and the potential for
synthetic assembly utilizing various monomeric building blocks,
make aminoglycosides ideal for the synthesis of new selective
and, potentially, less toxic drugs that can be used for studying
RNA binding. These efforts also demonstrated that synthetic
derivatives of aminoglycosides like neomycin 1 can exert im-
phosphonium bromide served as a mild proton source in the
allylation process to yield allyl glycosides a/b-6 (a : b =
1.3 : 1) in 73% which could easily be separated by column
chromatography.13 Formation of the Ferrier rearranged prod-
ucts was substantially suppressed by the polymer-bound proton
source (19%).14 Functional group manipulations became neces-
sary prior to olefin metathesis. After deacylation of glycoside
a-6, selective silylation at O-3 yielded allyl glycoside 7b which,
however, did not yield homodimers upon treatment with the
3 4 4 8
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6
T h i s j o u r n a l i s
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 4
©

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Scheme 1
Scheme 2
Grubbs’ catalyst 10. The two donor hydroxyl groups at both
C-4 positions in 7b could explain this result. The more reactive
ruthenium catalyst 11 was also ill suited for the olefin metathesis
reaction with the allyl glycosides, as substantial double bond
migration and formation of enol ether 12 (73%; E : Z = 1.6 :
1; along with recovery of 20% of starting material) occurred.15
Acylation of glycoside 7b yielded a fully protected allyl glycoside
which gave homodimer 8 after olefin metathesis with catalyst 10
and reductive hydrogenation. However, introduction of the allyl
group at both O-4 positions failed because the deacylation of
dimer 8 yielded complex mixtures due to silyl migration and
silyl removal.
bond in the resulting dimer was hydrogenated and methanolysis
of the acetyl groups afforded 1,4-butane diol linked glycoside 13.
Selective 3-O-silylation on both pyranose rings, this time using
the bulkier tert-butyldiphenylsilyl group proceeded smoothly
(94%), was followed by 4-O-allylation. The allylation turned
out to be troublesome because under classical conditions (NaH,
allyl bromide or CH2=CH–CH2OC(NH)CCl3, H+) either silyl
migration or desilylation and cleavage of the glycosidic bond
occurred, producing a complex mixture of products. Wong’s
procedure16 using allyl bromide in DMSO and LiHMDS as base
gave satisfactory results without resulting in these side reactions.
The target bisallylated product could be isolated in 48% yield.
Monoallylated product 16 was formed in 50% yield and could
be resubjected to the conditions to achieve complete allylation.
The homodimeric bisallylated product was liberated from the
Therefore, we had to alter the synthetic strategy and locate the
dimerization at an earlier stage of the synthesis, namely using
allyl glycoside a-6 as substrate (Scheme 2). The olefinic double
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6
3 4 4 9

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silyl protection which furnished diol 14. Below we investigated a
stereospecific introduction of the nitrogen source on both pyran
rings. The carbohydrate-derived bistriflate was reacted with the
nucleophilic azide anion which yielded the bisazido substitution
product. This intermediate was reduced to the corresponding
diamine and hence further transformed to the diamide 15.
Indeed, the introduction of the nitrogen functionality proceeded
with excellent stereoselectivity, but the yield for this process
was low (36%) which made the transformation from 14 to 15
and hence the whole route uneconomical in view of the price
of 15N-labelled azide. As an alternative, we tested the Barton
conditions of the Ritter reaction using chlorodiphenylmethyl
hexachloroantimonate as a free carbocation source to induce
activation of the hydroxyl groups in the presence of acetonitrile.17
Although the procedure works well with various alcohols, such
as menthol, it failed here and caused complete decomposition
of diol 14.
Therefore, we directed our efforts towards 1,4-butanediol-
linked diketone 17 (readily available from diol 14) (Scheme 3).
The advantage of this route is that a low cost 15N source
(ammonium-based) or derivatives can be utilized. Below re-
ductive amination using 15N-labelled NH4OAc (>98% purity)
afforded an intermediate diamine which, after trifluoroacetyla-
tion, furnished the homodimeric L-ristosamine derivative [15N]-
15 in 35% yield. The spectroscopic data are identical with those
collected for the reaction product obtained from the alternate
route via diol 14 and the corresponding ditriflate (Scheme 2). The
reductive amination step proceeded with high stereoselectivity
(ribo : arabino = 12 : 1). The ribo–arabino-mixed heterodimer
[15N]-18 was formed as a minor isomer (4%) and could be
separated by column chromatography.
Fig.
2
Calculated structure and main NOE connectivities of
aminocyanide 19 (these connectivities are also depicted in the graphic
created by a molecular modelling study): 5-Ha (6-Ha, 15NH), 15NH
(5-Ha, 3-Ha, 2-Hbeq, 5-Hb), 2-Hbax (2-Hbeq, 1-Hb, 4-Hb), 4-Hb (1-Hb, 2-Hb,
–O–CH2–CH=CH2b).
Scheme 4
imine formation between the amino group of [15N]-20 and the
remaining keto group took place which yielded macrocycle
[15N]-21. Subsequent nucleophilic attack of cyanide onto the
imino carbon generated amino nitrile [15N]-19. Surprisingly, no
macrocycle was detected with hydrogen instead of the cyano
group, which would have originated from hydride attack onto
the cyclic imine 21. However, under these conditions formation
of a symmetrical product would have occurred. Surprisingly, the
source of the cyanide ion in the present case is the reducing
agent.
When the L-ristosamine-derived head-to-head dimer [15N]-
15 was subjected to the metathesis protocol Scheme 5 the
Scheme 3
Interestingly, the cyclic by-product [15N]-19 was also isolated
in about 6% yield (single isomer). The structure was elucidated
by IR (m= 2279 cm−1, CN) and NMR spectroscopy as well as
mass spectrometry (ESI-MS: M+ = 438.26; >98% purity in 15N).
1
The H and 13C NMR spectra revealed that an unsymmetrical
molecule was formed which contained only one 15N nitrogen
atom (1H, 4.7 ppm, JNH = 81.5 Hz). 2D, TOCSY and NOE
experiments helped to fully elucidate the structure. Molecular
modelling calculations using the MMFF ForceField within
MacroModel 7.2 were conducted yielding a 3D structure which
supports the recorded NOE-data (Fig. 2).18–20,22,23
A possible mechanism for the formation of the unusual
macrocycle 19 is proposed in Scheme 4. Initially, only one keto
group underwent reductive amination. Then, intramolecular
Scheme 5
3 4 5 0
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6

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corresponding cyclic neo-tetrasaccharide [15N]-22 was formed
as the major product, while hexasaccharide [15N]-23 was the
only by-product that could be isolated. These structures were
unequivocally confirmed by NMR spectroscopy and impor-
tantly by mass spectrometry {[15N]4-22: LC-MS (ESI) (+c):
m/z (%): 1215.45 (100) [M + Na]+; [15N]6-23: LC-MS (ESI)
(+c): m/z (%): 1811.18 (100) [M + Na]+}. Finally, reduction
and deblocking yielded the target macrocyclic aminoglycosides
[15N]-2 and [15N]-24. Formation of these macrocycles can be
rationalized by assuming that the axial amido substituent at C-
3 prevents direct intramolecular olefin metathesis reaction of
dimer 15. Instead, dimerization and trimerization, respectively,
affording the linear tetra- and hexasaccharide intermediates,
occur prior to intramolecular ring closure.
Interestingly, the structurally reversed tail-to-tail dimer 25
yields the same set of macrocyclic tetramer 22 and hexamer 23
with similar ratio upon treatment with the catalyst 10.10 Thus,
the outcome of RCM is irrespective of the mode of connectivity
(butanediol bridge between C-4–C-4ꢀ or between C-1–C-1ꢀ) and
location of the allyl groups (C-1 or C-4) present in the dimeric
precursor.
Preparative column chromatography was performed on silica
gel 60 (E. Merck, Darmstadt). 15N-Ammonium acetate was
purchased from Aldrich (>98% purity).
Allyl 3,4-di-O-acetyl-2,6-dideoxy-a-L-arabino-pyranoside (6)
To a solution of 3,4-di-O-acetyl-L-rhamnal 5 (5 g, 23 mmol)
and allyl alcohol (2 g, 34.5 mmol, 1.5 eq) in dry CH2Cl2 (50
ml) was added polymer-bound PPh3·HBr (20 mg, 0.02 mmol).12
The reaction mixture was stirred at rt for 24 h, filtered through
a pad of Celite and concentrated under reduced pressure.
The crude product mixture was finally separated by column
chromatography (silica gel; ethyl acetate–petroleum ether 1 :
6) to yield a-6 (2.6 g, 9.56 mmol; 41%), b-6 (2.0 g, 7.35 mmol;
31.6%) and the Ferrier rearrangement product (1.0 g, 4.72 mmol;
18.7%). [a]2D6 = −156.3◦ (c 1, CHCl3); data for a-anomer 6 dH
(400 MHz; CDCl3) 1.17 (3 H, d, J 6.2, 6-H), 1.79 (1 H, ddd, J
12.8, 11.7 and 3.0, 2-Heq), 1.99 and 2.04 (6 H, 2 × s, 2 × AcO),
2.24 (1 H, ddd, J 12.8, 5.4 and 2.7, 2-Hax), 3.86 (1 H, dq, J 9.7
and 6.2, 5-H), 3.94 (1 H, ddt, J 13.0, 5.9 and 1.5, –O–CHHꢀ–
CH=), 4.13 (1 H, ddt, J 13.0, 5.2 and 1.5, –O–CHHꢀ–CH=),
4.73 (1 H, t, J 9.7, 4-H), 4.90 (1 H, d, J 3.0, 1-H), 5.18 (1 H,
dq, J 10.5 and 1.5, –CH=CHHꢀ), 5.29 (1 H, dq, J 17.1 and 1.5,
–CH=CHHꢀ), 5.30 (1 H, ddd, J 9.7, 5.4 and 2.7, 3-H), 5.89 (1
H, dddd, J 17.1, 10.5, 5.9 and 5.2, –CH=CH2); dC (100 MHz,
CDCl3) 17.8 (q, C-6), 21.1 and 21.3 (2 × q, 2 × COCH3), 35.6 (t,
C-2), 68.2 (t, –CH2–CH=), 66.0, 69.4 and 75.2 (3 × d, C-4, C-3,
C-5), 117.5 (t, –CH=CH2), 96.2 (d, C-1), 134.3 (d, –CH=CH2),
170.5 (2 × s, 2 × COCH3); LC-MS (ESI) (+c): m/z (%): 336.15
(100) [M + CH3CN + Na]+.
Conclusion
In summary, we have developed and evaluated new synthetic
routes towards macrocyclic 1,4-butanediol linked 15N-labelled
aminoglycosides. The synthetic strategy allows the preparation
of complex derivatives with good efficiency by introducing the
nitrogen functionality at a late stage of the synthesis using
15N-labelled ammonium acetate, which is readily available at
comparably low cost. Structural studies on the binding proper-
ties of these labelled aminoglycosides with biomacromolecules
(TAR-RNA) in solution are currently underway using NMR
spectroscopy.21 In essence, we believe that this synthetic work is
of general importance for the field of synthetic aminoglycosides
and their use as tools for studying RNA–ligand interactions.
1,4-Di-(2ꢀ,6ꢀ-dideoxy-a-L-arabino-pyranosyl)-1,4-butanediol (13)
Bisallyl glycoside a-6 (4 g, 15 mmol) was dissolved in dry benzene
(30 ml) and catalyst 10 (5 mg, 1 mol%) was added under argon
in one portion. The reaction mixture was stirred at 40 ◦C for
6 h and a second portion of catalyst 10 (5 mg, 1 mol%) was
added. Stirring was continued for additional 12 h at 40 ◦C
after which the solvent was removed under reduced pressure.
The crude product was subjected to column chromatography
(silica gel; ethyl acetate–petroleum ether 1 : 7) to yield the
unsaturated homodimer (3.1 g, 6.0 mmol; 80%). This material
was directly hydrogenated with H2 (1 bar) in ethyl acetate (25 ml)
using PtO2 (7 mol%). After 12 h at rt the reaction mixture was
filtered and concentrated in vacuo to yield the corresponding
saturated homodimeric saccharide (3.1 g, 5.97 mmol; >99%).
This material was directly employed for the next deacetylation
step.
Selected spectroscopic data of the crude material: dH
(200 MHz, CDCl3) 1.16 (6 H, d, J 6.4, 2 × 6-H), 1.64 (4 H,
m, 2 × –O–CH2–CH2–), 1.77 (2 H, ddd, J 12.7, 11.7 and 3.8,
2 × 2-Heq), 2.04 and 1.99 (12 H, 2 × s, 4 × AcO), 2.20 (2 H, ddd,
J 12.8, 5.4 and 0.9, 2 × 2-Hax), 3.35 (2 H, m, 2 × –O–CHHꢀ–
CH2–), 3.63 (2 H, m, 2 × –O–CHHꢀ–CH2–), 3.83 (2 H, dq, J 9.7
and 9.5, 2 × 5-H), 4.72 (2 H, dd, J 9.7 and 9.5, 2 × 4-H), 4.84
(2 H, d, J 2.9, 2 × 1-H), 5.25 (2 H, ddd, J 11.6, 9.6 and 5.5, 2 ×
3-H).
Deacetylation of the hydrogenated homodimer was achieved
by treatment of starting peracetate (3.1 g, 5.97 mmol) in
methanol (25 ml) with amberlite A-26 (hydroxide form, 0.6 g).
Stirring was continued at rt for 24 h. After filtration and removal
of the solvent in vacuo the crude product (2.08 g, 5.95 mmol;
99%) was dried and used for the next step without additional
purification.
dH (200 MHz, CD3OD = 3.35 ppm) 1.24 (6 H, d, J 6.3, 2 ×
6-H), 1.59 (2 H, ddd, J 12.9, 11.6 and 3.5, 2 × 2-Heq), 1.70 (4
H, m, 2 × –O–CH2–CH2–), 2.05 (2 H, ddd, J 12.9, 5.1 and 0.9,
2 × 2-Hax), 2.93 (2 H, t, J 9.3, 2 × 4-H), 3.44 (2 H, m, 2 ×
–O–CHHꢀ–CH2–), 3.58 (2 H, dq, J 9.3 and 6.3, 2 × 5-H), 3.66
(2 H, m, 2 × –O–CHHꢀ–CH2–), 3.77 (2 H, ddd, J 11.6, 9.3 and
5.1, 2 × 3-H), 4.80 (2 H, d, J 3.5, 1-H).
Experimental
General remarks and starting materials
1
1H NMR, 13C NMR and H, 13C-COSY as well as NOESY
spectra were measured on Avance 200/DPX (Bruker) with
200 MHz (50 MHz), Avance 400/DPX (Bruker) with 400 MHz
(100 MHz) and Avance 500/DRX (Bruker) with 500 MHz
(125 MHz), using tetramethylsilane as the internal standard.
If not otherwise noted, CDCl3 is the solvent for all NMR
experiments. Multiplicities are described using the following
abbreviations: s = singlet, d = doublet, t = triplet, q = quartet,
m = multiplet, br = broad. Chemical shift values of 13C NMR
spectra are reported as values in ppm relative to residual
CHCl3 (77 ppm) or CD3OD (49 ppm) as internal standards.
The multiplicities refer to the resonances in the off-resonance
spectra and were elucidated using distortionless enhancement by
polarisation transfer (DEPT) spectral editing techniques, with
secondary pulses at 90 and 135◦. Multiplicities are reported
using the following abbreviations: s = singlet (due to quaternary
carbon), d = doublet (methine), t = triplet (methylene), q
= quartet (methyl). Mass spectra were recorded on a type
LCT-spectrometer (Micromass) and on a type VG autospec
(Micromass). Ion mass (m/z) signals are reported as values
in atomic mass units followed, in parentheses, by the peak
intensities relative to the base peak (100%). Optical rotations
[a] were collected on a Polarimeter 341 (Perkin Elmer) at a
wavelength of 589 nm and are given in 10−1 deg cm2 g−1. Com-
bustion analyses were performed at the Institut fu¨r Organische
Chemie, Universita¨t Hannover. All solvents used were of reagent
grade and were further dried. Reactions were monitored by thin
layer chromatography (TLC) on silica gel 60 F254 (E. Merck,
Darmstadt) and spots were detected either by UV absorption or
by charring with H2SO4–4-methoxybenzaldehyde in methanol.
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6
3 4 5 1

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Allyl 3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-a-L-arabino-
pyranoside (7b)
was filtered and concentrated under reduced pressure to give the
product 8 (70 mg, 0.103 mmol; 99%) as a colorless oil.
dH (400 MHz, CDCl3) 0.02 and 0.03 (12 H, 4 × s, 2 × SiMe2),
0.83 (18 H, s, 2 × t-Bu), 1.12 (6 H, d, J 6.3, 2 × 6-H), 1.62 (4
H, m, 2 × –O–CH2–CH2–), 1.72 (2 H, ddd, J 13.3, 10.8 and 3.2,
2 × 2-Heq), 2.01 (2 H, dd, J 13.3 and 5.2, 2 × 2-Hax), 2.05 (6
H, s, 2 × CH3CO), 3.36 (2 H, m, 2 × –O–CHHꢀ–CH2–), 3.60 (2
H, m, 2 × –O–CHHꢀ–CH2–), 3.69 (2 H, dq, J 9.5 and 6.3, 2 ×
5-H), 4.00 (2 H, ddd, J 10.8, 9.1 and 5.2, 2 × 3-H), 4.61 (2 H,
dd, J 9.1 and 9.5, 2 × 4-H), 4.79 (2 H, d, J 3.2, 2 × 1-H); dC
(100 MHz, CDCl3) −4.9 and −4.5 (2 × q, Si(CH3)2), 17.6 (q,
2 × C-6), 17.8 (s, 2 × SiC(CH3)3), 21.1 (q, 2 × COCH3), 25.5 (q,
2 × SiC(CH3)3), 26.4 (t, 2 × –O–CH2–CH2–), 39.2 (t, 2 × C-2),
67.0 (t, 2 × –O–CH2–CH2–), 67.5, 65.9 (2 × d, 2 × C-3, 2 ×
C-5), 77.8 (d, 2 × 4-H), 97.1 (d, 2 × 1-H), 169.9 (s, 2 × COCH3);
elemental analysis calcd. (%) for C15H30O4Si (302.48): C 59.56,
H 10.00; found C 59.44 H 10.10.
To a stirred solution of allylated sugar 6 (3.36 g 10.0 mmol) in
methanol (50 ml) was added Amberlite A-26 (OH− form) (1 g).
After 24 h the reaction mixture was filtered and the solvent was
removed under reduced pressure. The product was dried under
reduced pressure for 4 h and directly used for the next step. Yield:
1.90 g (10.0 mmol, >98%).
To a stirred solution of 2-deoxy-a-allyl-L-rhamnoside (1.90 g,
0.01 mol), imidazole (1.0 g, 0.015 mol, 1.5 eq) and DMAP (cat.)
in DMF◦(15 ml) was slowly added TBSCl◦(1.55g, 0.01 mol, 1
eq) at 0 C. The solution was stirred at 0 C for 4 h and then
at rt for additional 12 h. The pure product 7b was isolated after
purification by flash column chromatography as colorless oil.
Yield: 2.68 g (8.86 mmol, 89%).
dH (400 MHz, CDCl3) 0.09 and 0.11 (6 H, 2 × s, Si(CH3)2), 0.89
(9 H, s, t-Bu–Si), 1.28 (3 H, d, J 6.2, 6-H), 1.68 (1 H, ddd, J 12.9,
11.3 and 3.4, 2-Heq), 2.02 (1 H, ddd, J 12.9, 5.1 and 1.1, 2-Hax),
2.23 (1 H, d, J 2.0, OH), 3.10 (1 H, dt, J 9.1 and 2.0, 4-H), 3.68 (1
H, dq, J 9.1 and 6.2, 5-H), 3.93 (2 H, m, –O–CHHꢀ–CH=, 3-H),
4.12 (1 H, ddt, J 13.2, 4.9 and 1.5, –O–CHHꢀ–CH=), 4.85 (1 H,
d, J 3.4, 1-H), 5.16 (1 H, dq, J 10.5 and 1.5, –CH=CHHꢀ), 5.27
(1 H, dq, J 17.1 and 1.6, –CH=CHHꢀ), 5.90 (1 H, dddd, J 17.1,
10.5, 5.8 and 4.9, –CH=CH2); dC (100 MHz, CDCl3) −4.64 and
−4.20 (2 × q, Si(CH3)2), 17.84 (q, C-6), 17.98 (s, Si-C(CH3)3),
25.76 (q, Si–C(CH3)3), 38.63 (t, C-2), 67.55 (t, –CH2–CH=),
67.46, 70.56 and 78.02 (3 × d, C-3, C-4, C-5), 96.61 (d, C-1),
116.58 (t, –CH=CH2), 134.40 (d, –CH=CH2).
1-O-Prop-1-(E/Z)enyl-3,4-di-O-acetyl-2,6-dideoxy-a-L-
arabino-pyranoside (12)
When allyl glycoside (a)-6 was subjected to identical reaction
conditions as described above (except that Grubbs’ catalyst
11 was employed) pyranoside 12 was isolated after column
chromatography (73%, E : Z= 1.6 : 1) and 20% of recovered
starting allyl glycoside 6.
dH (400 MHz; CDCl3) 1.18 and 1.19 (6 H, 2 × d, J 6.3, 6-H,
6-Hꢀ), 1.48 and 1.50 (6H, 2 × dd, J 7.0 and 1.6, J 6.3 and 1.6,
=CH–CH3, =CHꢀ–CH3), 1.74 and 1.79 (2 H, 2 × ddd, J 12.8,
11.7 and 3.0, 2-Heq, 2-Hꢀeq), 1.97, 1.99, 2.03 and 2.04 (12 H, 4
× s, 4 × AcO), 2.24 (2 H, ddd, J 12.8, 5.4 and 2.7, 2-Hax, 2-Hꢀax),
3.79 and 3.86 (2 H, 2 × dq, J 9.7 and 6.3, 5-H, 5-Hꢀ), 4.42 (1 H,
dq, J 6.3 and 6.3, =CHꢀ–CH3), 4.73 and 4.78 (2 H, 2 × t, J 9.7,
4-H, 4-Hꢀ), 4.90 and 5.12 (2 H, 2 × d, J 3.0, 1-H, 1-Hꢀ), 4.92 (1
H, dq, J 12.1 and 7.0, =CH–CH3), 5.30 (2 H, m, 3-H, 3-Hꢀ), 5.92
(1 H, dq, J 6.3 and 1.6, O–CHꢀ=CH–), 6.10 (1 H, dq, J 12.1
and 1.6, O–CH=CH–); dC (100 MHz, CDCl3) 8.9 and 11.8 (2 ×
1,4-Di-(4ꢀ-O-acetyl-3ꢀ-O-(tert-butyldimethylsilyl)-2ꢀ,6ꢀ-dideoxy-
a-L-arabino-pyranosyl)-1,4-butanediol (8)
Alcohol 7b (2.58 g, 8.5 mmol) was dissolved in dry pyridine
(10 ml) and Ac2O (1.02 ml, 11.05 mmol, 1.3 eq) was added.
The reaction mixture was stirred overnight at rt. The sol-
vent was evaporated under reduced pressure and the residue
was extracted with ethyl acetate, washed with water, dried
(MgSO4) and again concentrated under reduced pressure to
yield allyl 4-O-acetyl-3-O-(tert-butyldimethylsilyl)-2,6-dideoxy-
a-L-arabino-pyranoside (2.9 g, 8.4 mmol; 99%).
q, =CH–CH3, =CH–CH3 ), 17.8 and 17.9 (2 × q, C-6, C-6ꢀ),
ꢀ
21.1, 21.2 and 21.3 (4 × q, 4 × COCH3), 35.5 and 35.6 (2 × t,
C-2, C-2ꢀ), 65.9, 66.0, 69.2, 69.4, 75.2 and 75.6 (6 × d, C-4, C-4ꢀ,
C-3, C-3ꢀ, C-5, C-5ꢀ), 95.3 and 96.2 (2 × d, C-1, C-1ꢀ), 102.8 and
103.0 (2 × d, =CH–CH3, =CHꢀ–CH3), 145.3 and 146.1 (2 × d,
–O–CH=, –O–CHꢀ=), 170.5 (4 × s, 4 × COCH3); LC-MS (ESI)
(+c): m/z (%): 273.1283 (100) [M+H]+.
dH (400 MHz, CDCl3) 0.03 and 0.04 (6 H, 2 × s, Me2Si), 0.84
(9.H, s, t-BuSi), 1.13 (3 H, d, J 6.2, 6-H), 1.75 (1 H, ddd, J 13.1,
11.3 and 3.3, 2-Heq), 2.06 (1 H, ddd, J 13.1, 5.3 and 1.1, 2-Hax),
2.06 (3 H, s, CH3CO), 3.73 (1 H, dq, J 9.5 and 6.2, 5-H), 3.92 (1
H, ddt, J 13.1, 5.8 and 1.3, –O–CHHꢀ–CH=), 4.05 (1 H, ddd,
J 11.3, 9.5 and 5.3, 3-H), 4.11(1 H, ddt, J 13.1, 5.0 and 1.5,
–O–CHHꢀ–CH=), 4.63 (1 H, t, J 9.5, 4-H), 4.86 (1 H, d, J 3.3,
1-H), 5.18 (1 H, dq, J 10.5 and 1.4, –CH=CHHꢀ), 5.27 (1 H,
dq, J 17.2 and 1.6, –CH=CHHꢀ), 5.90 (1 H, dddd, J 17.2, 10.5,
5.8 and 5.0, –CH=CH2); dC (100 MHz, CDCl3) −4.6 and −4.2
(2 × q, Si(CH3)2), 17.9 (q, C-6), 18.1 (s, Si–C(CH3)3), 21.5 (q,
COCH3), 25.9 (q, Si–C(CH3)3), 39.4 (t, C-2), 66.3, 67.8 and 78.1
(3 × d, C-3, C-4, C-5), 68.0 (t, –CH2–CH=), 96.7 (d, C-1), 117.1
(t, –CH=CH2), 134.6 (d, –CH=CH2), 170.3 (s, COCH3).
This allyl glycoside (100 mg, 0.29 mmol) was dissolved in
dry benzene (3 ml) and Grubbs’ catalyst 10 (5 mg, 1 mol%) was
added under argon. The reaction mixture was stirred for 6 h, then
a second portion of the catalyst (5 mg, 1 mol%) was added and
the mixture was stirred for additional 12 h. Then, the reaction
temperature was elevated to 40 ◦C and an additional portion of
the catalyst was added (10 mg, 2 mol% in two portions within
24 h). The solvent was evaporated under reduced pressure and
the residue was purified by column chromatography on silica gel
(ethyl acetate–petroleum ether 1 : 10) to yield the target cross
coupling olefin (69 mg, 0.104 mmol; 72%) and unreacted starting
material (20 mg, 0.058 mmol, 20%).
1,4-Di-(4ꢀ-O-allyl-2ꢀ,6ꢀ-dideoxy-a-L-arabino-pyranosyl)-1,4-
butanediol (14)
To a solution of tetrol 13 (393 mg, 1.13 mmol), imidazole
(223 mg, 3.3 mmol), DMAP (10 mg, cat.) in dry DMF (10
ml) was slowly added tert-butyldiphenylsilyl chloride (565 mg,
2.26 mmol) at 0 ◦C. The solution was stirred at 0 ◦C for
4 h and then allowed to warm up to rt. After additional
12 h the reaction was terminated by addition of n-hexane
(10 ml). The DMF phase was extracted with n-hexane (2 ×
5 ml) and the combined hexane phases were concentrated
under reduced pressure. The crude material was subjected
to silica gel filtration (petroleum ether–ethyl acetate 10 :
1) after which 1,4-di-(3ꢀ-O-tert-butyldiphenylsilyl-2ꢀ,6ꢀ-dideoxy-
a-L-arabino-pyranosyl)-1,4-butanediol was isolated (857 mg,
1.034 mmol; 94%).
dH (200 MHz, CDCl3) 1.08 (9 H, s, t-Bu), 1.25 (6 H, d, J 6.3,
2 × 6-H), 1.33 (4 H, m, 2 × –O–CH2–CH2–), 1.67 (2 H, ddd, J
12.6, 11.2 and 2.8, 2 × 2-Heq), 1.84 (2 H, ddd, J 12.6, 5.1 and
0.9, 2 × 2-Hax), 2.14 (2 H, d, J 2.6, 2 × OH), 3.15 (2 H, m, 2 ×
–O–CHHꢀ–CH2–), 3.23 (2 H, ddd, J 9.1, 9.0 and 2.5, 2 × 4-H),
3.44 (2 H, m, 2 × –O–CHHꢀ–CH2–), 3.50 (2 H, dq, J 9.1 and
6.3, 2 × 5-H), 4.01 (2 H, ddd, J 11.2, 9.0 and 5.1, 2 × 3-H), 4.63
(2 × H, d, J 2.8, 2 × 1-H), 7.68 (8 H, m, Ar), 7.38 (12 H, m, Ar).
To a vigorously stirred solution of this homodimeric diol
(4.6 g, 5.5 mmol) and allyl bromide (9.4 ml, 110.0 mmol) was
This dimeric alkene (69 mg, 0.104 mmol) was dissolved in
a mixture of solvents (ethyl acetate–CH2Cl2–MeOH 16 : 8 : 1;
5 ml) and PtO2 (1.6 mg, 7 mol%) was added. This suspension
was stirred for 5 h under H2 atmosphere. The reaction mixture
3 4 5 2
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6

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added LiN(SiMe3)2 (6.45 g, 38.5 mmol) at 0 ◦C. After 5 min the
reaction was diluted with ethyl acetate and water. The organic
layer was washed with water until it reached neutral pH. The
organic phase was dried (MgSO4), filtered and concentrated in
vacuo. The crude oil was purified by column chromatography
on silica gel (ethyl acetate–petroleum ether 1 : 10) to yield
bisallylated homodimer, along with monoallylated product 16
(2.39 g, 2.75 mmol; 50%). The latter can be used for another
allylation step according to the procedure described above.
1st fraction. Bisallylated homodimer [1,4-di-(4ꢀ-O-allyl-3ꢀ-
O-tert-butyldiphenylsilyl-2ꢀ,6ꢀ-dideoxy-a-L-arabino-pyranosyl)-
1,4-butanediol] (2.4 g, 2.64 mmol, 48%); colorless oil; dH
(400 MHz, CDCl3) 1.10 (18 H, s, 2 × t-Bu), 1.27 (4 H, m, 2 ×
–O–CH2–CH2–), 1.28 (6 H, d, J 6.3, 2 × 6-H), 1.54 (4 H, m,
2 × 2-H), 3.02 (2 H, dd, J 9.3 and 9.0, 2 × 4-H), 3.05 (2 H, m,
2 × –O–CHHꢀ–CH2–), 3.39 (2 H, m, 2 × –O–CHHꢀ–CH2–),
3.60 (2 H, dq, J 9.3 and 6.3, 2 × 5-H), 4.18 (2 H, dd, J 12.0 and
6.0, 2 × –O–CHHꢀ–CH=), 4.25 (2 H, ddd, J 10.1, 9.0 and 5.9,
2 × 3-H), 4.50 (2 H, dd, J 12.0 and 5.4, 2 × –O–CHHꢀ–CH=),
4.52 (2 H, br s, 2 × 1-H), 5.20 (2 H, dd, J 10.3 and 1.7, 2 ×
–CH=CHHꢀ), 5.28 (2 H, dd, J 17.2 and 1.7, 2 × –CH=CHHꢀ),
5.97 (2 H, dddd, J 17.2, 10.3, 6.0 and 5.4, 2 × –CH=CH2), 7.71
(4 H, dd, J = 7.9 and 1.5, Ar), 7.36 (12 H, m, Ar), 7.76 (4 H, dd,
J = 7.9 and 1.5, Ar); dC (100 MHz, CDCl3) 18.2 (q, 2 × C-6),
19.2 (s, 2 × SiC(CH3)3), 26.0 (t, 2 × –O–CH2–CH2–), 27.0 (q,
2 × SiC(CH3)3), 38.9 (t, 2 × C-2), 66.5 (t, 2 × –O–CH2–CH2–),
67.2 (d, 2 × C-5), 71.1 (d, 2 × C-3), 74.3 (t, 2 × –CH2–CH=),
85.7 (d, 2 × C-4), 96.9 (d, 2 × C-1), 116.8 (t, 2 × –CH=CH2),
129.6, 129.5, 127.4 (3 × d, 6 × Ar), 133.8 (s, 2 × Ar), 134.9 (s,
2 × Ar), 135.1 (d, 2 × –CH=CH2), 135.8 (d, 2 × Ar), 135.9 (d,
2 × Ar).
dd, J 9.3 and 9.1, 2 × 4-H), 3.36 (2 H, dt, J 9.5 and 6.0, 2 ×
–O–CHHꢀ–CH2–), 3.63 (2 H, dt, J 9.4 and 6.4, 2 × –O–CHHꢀ–
CH2–), 3.66 (2 H, dq, J 9.3 and 6.3, 2 × 5-H), 4.00 (2 H, dddd,
J 11.7, 9.1, 5.2 and 3.2, 2 × 3-H), 4.25 (4 H, dq, J 5.7 and 1.4,
2 × –O–CH2–CH=), 4.83 (2 H, d, J 3.5, 2 × 1-H), 5.22 (2 H,
dq, J 10.4 and 1.4, 2 × –CH=CHHꢀ), 5.32 (2 H, dq, J 17.2
and 1.4, 2 × –CH=CHHꢀ), 5.97 (2 H, dddd, J 17.2, 10.4, 5.7
and 5.7, 2 × –CH=CH2); dC (125 MHz, CDCl3) 18.2 (q, 2 ×
C-6), 26.4 (t, 2 × –O–CH2–CH2–), 37.7 (t, 2 × C-2), 66.9 (t, 2 ×
–O–CH2–CH2–), 67.0 (d, 2 × C-5), 68.7 (d, 2 × C-3), 74.0 (t,
2 × –CH2–CH=), 86.4 (d, 2 × C-4), 97.1 (d, 2 × C-1), 117.2 (t,
2 × –CH=CH2), 134.9 (d, 2 × –CH=CH2); elemental analysis
calcd. (%) for C22H38O8 (430.53): C 61.37, H 8.90; found C 61.29,
H 8.78.
1,4-Di-(4ꢀ-O-allyl-2ꢀ,3ꢀ,6ꢀ-trideoxy-3ꢀ-trifluoroacetamido-a-L-
ribo-hexopyranosyl)-1,4-butanediol (15)
To a solution of diol 14 (100 mg, 0.23 mmol) in dry CH2Cl2 (20
ml) with pyridine as a base (100 ll) at −15 ◦C Tf2O (138 mg, 0.49
mmol) in dry CH2Cl2 (5 ml) was added. The reaction mixture was
stirred for 2 h, diluted with water and extracted with petroleum
ether (2 × 40 ml). The organic extracts were combined, washed
with water, dried (MgSO4) and the solvent was evaporated under
reduced pressure. The crude product was dissolved in a small
amount of CH2Cl2 and filtered through a small column of silica
gel to yield the highly labile bistriflate (125 mg, 0.22 mmol; 96%)
as a colorless oil.
dH (200 MHz, CDCl3) 1.29 (6 H, d, J 6.2, 2 × 6-H), 1.38 (4
H, m, 2 × –O–CH2–CH2–), 1.63 (2 H, dt, J 12.3 and 3.1, 2 ×
2-Heq), 2.29 (2 H, ddd, J 12.3, 5.3 and 0.9, 2 × 2-Hax), 2.90 (2 H,
t, J 9.2, 2 × 4-H), 3.05 (2 H, m, 2 × –O–CHHꢀ–CH2–), 3.38 (2
H, m, 2 × –O–CHHꢀ–CH2–), 3.77 (2 H, dq, J 9.2 and 6.2, 2 ×
5-H), 3.91 (2 H, ddt, J 12.1, 5.5 and 1.0, 2 × =CH–CHHꢀ–O–),
4.18 (2 H, ddt, J 12.1, 5.5 and 1.2, 2 × =CH–CHHꢀ–O–), 4.51
(2 H, d, J 3.1, 2 × 1-H), 5.11 (2 H, dq, J 10.3 and 1.5, 2 ×
–CH=CHHꢀ), 5.27 (2 H, dq, J 17.2 and 1.5, 2 × –CH=CHHꢀ),
5.41 (2 H, ddd, J 12.3, 9.2 and 5.3, 2 × 3-H), 5.93 (2 H, ddt, J
17.2, 10.3 and 5.5, 2H, 2 × –CH=).
2nd fraction. [1-(4ꢀ-O-allyl-3ꢀ-O-tert-butyldiphenylsilyl-2ꢀ,6ꢀ-
dideoxy-a-L-arabino-pyranosyl)-4-(3ꢀ-O-tert-butyldiphenylsilyl-
2ꢀ,6ꢀ-dideoxy-a-L-arabino-pyranosyl)-1,4-butanediol] (16); dH
(500 MHz, CDCl3) 1.09 (9 H, s, t-Bu), 1.25 (3 H, d, J 6.1, 6-Hꢀ),
1.26 (3 H, d, J 6.2, 6-H), 1.62 (6 H, m, 2 × –O–CH2–CH2–,
2-Heq, 2-Hꢀeq), 2.01 (2 H, ddd, J 13.0, 4.0 and 3.7, 2-Hax, 2-Haxꢀ),
2.26 (1 H, d, J 2.0, OH), 2.85 (1 H, dd, J 9.2 and 9.1, 4-Hꢀ),
3.11 (1 H, ddd, J 9.2, 8.7 and 2.0, 4-H), 3.63 (4 H, m, 5-H,
5-Hꢀ, –O–CH2–CH2–), 3.34 (2 H, m, –O–CH2–CH2–), 3.90 (1
H, ddd, J 11.1, 8.7 and 4.9, 3-H), 3.96 (1 H, ddd, J 10.9, 9.2 and
5.1, 3-Hꢀ), 4.03 (1 H, dd, J 12.2 and 6.0, –O–CHHꢀ–CH=), 4.33
(1 H, dd, J 12.2 and 5.4, –O–CHHꢀ–CH=), 4.77, 4.75 (2 H, 2 ×
d, 2 × J 3.0, 1-H, 1-Hꢀ), 5.17 (1 H, d, J 10.6, –CH=CHHꢀ),
5.26 (1 H, dd, J 17.1 and 1.5, –CH=CHHꢀ), 5.95 (1 H, dddd,
J 17.1, 10.6, 5.8 and 5.8, –CH=CH2), 7.34 (6 H, m, Ar), 7.67
(2 H, dd, J 7.9 and 1.5, Ar), 7.73 (2 H, dd, J 7.9 and 1.5, Ar);
dC (125 MHz, CDCl3) 17.8 and 17.9 (2 × q, C-6, C-6ꢀ), 19.2 (s,
SiC(CH3)3), 26.4 and 26.4 (2 × t, 2 × –O–CH2–CH2–), 27.0 (q,
SiC(CH3)3), 38.7 and 39.5 (2 × t, C-2, C-2ꢀ), 66.8 and 66.9 (2 ×
t, 2 × –O–CH2–CH2–), 67.2 and 67.3 (2 × d, C-5, C-5ꢀ), 70.2 (d,
C-3ꢀ), 70.6 (d, C-3), 74.3 (t, –CH2–CH=), 78.0 (d, C-4), 85.3 (d,
C-4ꢀ), 97.1 (d, C-1ꢀ), 97.3 (d, C-1), 116.8 (t, –CH=CH2), 129.3
and 129.4 (2 × d, 3 × Ar), 133.8 (s, Ar), 134.9 (s, Ar), 135.2 (d,
–CH=CH2), 135.8 (d, Ar), 135.9 (d, Ar).
A solution of this bistriflate (200 mg, 0.465 mmol) in dry
benzene (1 ml) was treated with tetra-n-butylammonium azide
(300 mg, 1.06 mmol, 2.3 eq). The reaction mixture was heated
◦
at 70 C for 15 min, diluted with water (10 ml) and extracted
with ethyl acetate (3 × 30 ml). The organic extracts were
combined, dried (MgSO4) and solvent was evaporated under
reduced pressure. The crude product was purified by column
chromatography (silica gel; ethyl acetate–petroleum ether 1 : 12)
to yield the 1,4-di-(4ꢀ-O-allyl-3ꢀ-azido-2ꢀ,3ꢀ,6ꢀ-trideoxy-a-L-ribo-
hexopyranosyl)-1,4-butanediol (80 mg, 0.167 mmol; 36%).
dH (500 MHz, C6D6, C6D6 = 7.16 ppm) 1.31 (6 H, d, J 6.2,
2 × 6-H), 1.33 (2 H, dt, J 14.5 and 4.1, 2 × 2-Heq), 1.76 (4 H,
m, 2 × –O–CH2–CH2–),1.85 (2 H, ddd, J 14.5, 3.4 and 0.9, 2 ×
2-Hax), 2.82 (2 H, dd, J 9.1 and 3.8, 2 × 4-H), 3.26 (2 H, m, 2 ×
–O–CHHꢀ–CH2–), 3.41 (2 H, dt, J 3.8 and 3.4, 2 × 3-H), 3.60 (2
H, dd, J 12.7 and 5.4, 2 × –O–CHHꢀ–CH=), 3.70 (2 H, m, 2 ×
–O–CHHꢀ–CH2–), 3.85 (2 H, dd, J 12.7 and 5.4, 2 × –O–CHHꢀ–
CH=), 4.25 (2 H, dq, J 9.1 and 6.2, 2 × 5-H), 4.53 (2 H, d, J 4.1,
2 × 1-H), 5.01 (2 H, br dd, J 10.4 and 1.4, 2 × –CH=CHHꢀ),
5.18 (2 H, dq, J 17.2 and 1.4, 2 × –CH=CHHꢀ), 5.78 (2 H,
ddt, J 17.2, 10.4 and 5.4, 2 × –CH=CH2); dC (125 MHz, C6D6,
C6D6 = 128.06 ppm) 18.2 (q, 2 × C-6), 26.9 (t, 2 × –O–CH2–
CH2–), 33.0 (t, 2 × C-2), 54.8 (d, 2 × C-3), 63.4 (d, 2 × C-5),
67.4 (t, 2 × –O–CH2–CH2–), 69.9 (t, 2 × –CH2–CH=), 80.1 (d,
2 × C-4), 95.6 (d, 2 × C-1), 116.7 (t, 2 × –CH=CH2), 135.1
(d, 2 × –CH=CH2); LC-MS (ESI) (+c): m/z (%): 453.26 (100)
[M–N2]+, 487.26 (92) [M + Li]+, 503.24 (88) [M + Na]+; HR-MS
C22H36N6O6 + 23Na: calcd. 503.2594, found 503.2593.
A
solution (1 M) of tetra-n-butyl ammonium fluo-
ride (1.65 mmol, 1.65 ml, eq) in THF was added
3
to a solution of 1,4-di-(4ꢀ-O-allyl-3ꢀ-O-tert-butyldiphenylsilyl-
2ꢀ,6ꢀ-dideoxy-a-L-arabino-pyranosyl)-1,4-butanediol (0.5 g, 0.55
mmol) in THF (10 ml). The solution was stirred overnight, the
solvent was removed under reduced pressure and the crude
material was purified by column chromatography (silica gel;
petroleum ether–ethyl acetate 1 : 3) to give the corresponding
diol 14 (200 mg, 0.465 mmol; 85%) as a colorless, amorphous
powder.
dH (500 MHz, CDCl3) 1.30 (6 H, d, J 6.3, 2 × 6-H), 1,63 (4
H, ddd J 6.4, 6.4 and 6.4, 2 × –O–CH2–CH2–), 1.69 (2 H, ddd,
J 12.9, 11.7 and 3.5, 2 × 2-Heq), 2.13 (2 H, ddd, J 12.9, 5.2 and
1.1, 2 × 2-Hax), 2.34 (2 H, d, J 3.1, 2 × OH), 2.87 (2 H, br
A solution of 1,4-di-(4ꢀ-O-allyl-3ꢀ-azido-2ꢀ,3ꢀ,6ꢀ-trideoxy-a-L-
ribo-hexopyranosyl)-1,4-butanediol (80 mg, 0.167 mmol) in dry
THF (5 ml) is added to a solution of LiAlH4 (25 mg, 0.66 mmol)
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6
3 4 5 3

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in dry THF (10 ml). The reaction mixture was stirred for 45 min.
at rt, then NaF (500 mg) was added followed by a careful
addition of a water–THF mixture (1 ml water, 4 ml THF).
The resulting suspension was stirred for an additional hour,
filtered and the solvent was evaporated under reduced pressure.
The crude amine was dissolved in CH2Cl2 (25 ml) and dry
triethylamine (50 mg, 0.5 mmol, 3 eq) was added at 0 ◦C followed
by addition of trifluoroacetic anhydride (105 mg, 0.5 mmol).
The mixture was stirred at rt for 30 min, whereupon TLC
(ethyl acetate–petroleum ether 1 : 5) revealed that acylation
was complete. The mixture was concentrated under reduced
pressure to afford a crude product which was purified by column
chromatography (silica gel; ethyl acetate–petroleum ether 1 : 7)
to yield pure diamide 15 (62 mg, 0.1 mmol; 60% for two steps).
dH (500 MHz, C6D6, C6D6 = 7.16 ppm) 1.41 (6 H, d, J 6.2,
2 × 6-H), 1.3–1.6 (8 H, m, 2 × 2-Hax, 2 × 2-Heq, 2 × –O–CH2–
CH2–), 2.89 (2 H, dd, J 9.5 and 3.9, 2 × 4-H), 3.06 (2 H, m, 2 ×
–O–CHHꢀ–CH2–), 3.56 (2 H, m, 2 × –O–CHHꢀ–CH2–), 3.84 (2
H, dq, J 9.5 and 6.2, 2 × 5-H), 3.85 (2 H, dd, J 12.5 and 6.0,
2 × –O–CHHꢀ–CH=), 4.38 (2 H, dd, J 12.5 and 5.3, 2 × –O–
CHHꢀ–CH=), 4.48 (2 H, d, J 3.0, 2 × 1-H), 4.50 (2 H, m, 2 ×
3-H), 5.15 (2 H, br dd, J 10.4 and 1.3, 2 × –CH=CHHꢀ), 5.34
(2 H, dq, J 17.2 and 1.3, 2 × –CH=CHHꢀ), 5.97 (2 H, dddd,
J 17.2, 10.4, 6.0 and 5.3, 2 × –CH=CH2), 8.00 (2 H, d, J 8.5,
2 × NH); dC (125 MHz, C6D6, C6D6 = 128.06 ppm), 18.3 (q,
2 × C-6), 26.6 (t, 2 × –O–CH2–CH2–), 32.7 (t, 2 × C-2), 43.7
(d, 2 × C-3), 63.5 (d, 2 × C-5), 67.4 (t, 2 × –O–CH2–CH2–),
70.5 (t, 2 × –CH2–CH=), 78.1 (d, 2 × C-4), 96.8 (d, 2 × C-1),
117.1 (t, 2 × –CH=CH2), 135.1 (d, 2 × –CH=CH2); HR-MS
C26H38F6N2O823Na: calcd. 643.2430, found 643.2435.
of the second portion of NaBH3CN (105 mg, 1.64 mmol). The
reaction mixture was allowed to stir for another 24 h after which
triethylamine (1.5 ml, 10 mmol) and CF3COOEt (3.6 ml, 30
mmol) were added. The reaction mixture was stirred overnight at
rt. The solvent was evaporated under reduced pressure. Prior to
column chromatography the crude product was separated from
trifluoroacetamide by sublimation in high vacuum (0.01 mbar,
60 ◦C, 30 min). The remaining residue was purified by column
chromatography (silica gel; ethyl acetate–petroleum ether 1 : 5)
to yield three fractions:
1st fraction. [15N]2-15 (177 mg, 0.284 mmol; 35%); dH
(500 MHz, C6D6, C6D6 = 7.16 ppm) 1.30 (6 H, d, J 6.2, 2 × 6-
H), 1.2–1.5 (8 H, m, 2 × 2-Hax, 2 × 2-Heq, 2 × –O–CH2–CH2–),
2.77 (2 H, ddd, J 9.6, 3.8 and 3.8, 2 × 4-H), 2.95 (2 H, m, 2 ×
–O–CHHꢀ–CH2–), 3.44 (2 H, m, 2 × –O–CHHꢀ–CH2–), 3.85 (4
H, m, 2 × –O–CHHꢀ–CH=, 2 × 5-H), 4.27 (2 H, dd, J 12.4
and 5.3, 2 × –O–CHHꢀ–CH=), 4.37 (2 H, d, J 3.2, 2 × 1-H),
4.38 (2 H, m, 2 × 3-H), 5.03 (2 H, br dd, J 10.3 and 1.34, 2 ×
–CH=CHHꢀ), 5.22 (2 H, dq, J 17.2 and 1.6, 2 × –CH=CHHꢀ),
5.86 (2 H, dddd, J 17.2, 10.3, 6.4 and 5.3, 2 × –CH=CH2), 7.89
(2 H, dd, J 92.1 and 9.1, 2 × NH); dC (125 MHz, C6D6, C6D6 =
128 ppm) 18.3 (q, 2 × C-6), 26.6 (t, 2 × –O–CH2–CH2–), 32.7
(t, 2 × C-2), 43.8, 43.7 (d, 2 × C-3), 63.5 (d, 2 × C-5), 67.4 (t,
2 × –O–CH2–CH2–), 70.5 (t, 2 × –CH2–CH=), 78.1 (d, 2 ×
C-4), 96.8 (d, 2 × C-1), 117.1 (t, 2 × –CH=CH2), 135.1 (d, 2 ×
–CH=CH2), 157.1, 156.9, 156.8, 156.7, 156.5, 156.4, 156.2 (s,
2 × COCF3);
2nd fraction. 18 (20 mg, 32 lmol; 3.9%); the ribo-configured
a
pyran is labelled with the letter while the arabino-configured
b
pyran is labelled as ; dH (500 MHz, C6D6, C6D6 = 7.16 ppm)
1,4-Di-(4ꢀ-O-allyl-2ꢀ,6ꢀ-dideoxy-3ꢀ-oxo-a-L-arabino-pyranosyl)-
1,4-butanediol (17)
1.38 (1 H, m, 2-Heqa), 1.38 (3 H, d, J 6.1, 6-Hb), 1.39 (3 H, d, J
6.1, 6-Ha), 1.55 (5 H, m, 2-Haxa, 2 × –O–CH2–CH2–), 1.68 (1 H,
dt, J 13.2 and 3.6, 2-Heqb), 1.97 (1 H, dd, J 12.9 and 4.6, 2-Haxb),
2.88 (1 H, ddd, J 9.6, 3.7 and 3.7, 4-Ha), 2.95 (1 H, t, J 9.5,
4-Hb), 3.08, 3.22 and 3.60 (4 H, 3 × m, 2 × –O–CH2–CH2–),
To a solution of diol 14 (51 mg, 0.118 mmol) in dry CH2Cl2 was
added Dess–Martin periodinane (111 mg, 0.261 mmol). The
mixture was stirred at rt for 3 h, after which TLC (ethyl acetate–
petroleum ether 1 : 3) revealed that oxidation was completed.
Remaining oxidant was destroyed by washing with aqueous
Na2S2O3 solution. The organic phase was dried (MgSO4) and
concentrated under reduced pressure. The crude product was
purified by column chromatography on silica gel (ethyl acetate–
petroleum ether 1 : 5) yielding bisulose 17 (50 mg, 0.117 mmol;
>99%) as fine colorless crystals which was used directly in the
next step.
dH (500 MHz, C6D6, C6D6 = 7.16 ppm) 1.43 (4 H, br q, J 5.8,
2 × –O–CH2–CH2–), 1.52 (6 H, d, J 6.2, 2 × 6-H), 2.27 (2 H,
dd, J 14.0 and 4.3, 2 × 2-Heq), 2.50 (2 H, br d, J 14.0, 2 × 2-Hax),
3.10 (2 H, dt, J 9.4 and 5.8, 2 × –O–CHHꢀ–CH2–), 3.43 (2 H, br
d, J 9.5, 2 × 4-H), 3.46 (2 H, dt, J 10.0 and 6.3, 2 × –O–CHHꢀ–
CH2–), 3.99 (2 H, br dd, J 12.7 and 6.2, 2 × –O–CHHꢀ–CH=),
4.17 (2 H, dq, J 9.5 and 6.2, 2 × 5-H), 4.56 (2 H, br ddt, J 12.7,
5.0 and, 1.4, 2 × –O–CHHꢀ–CH=), 4.79 (2 H, d, J 4.3, 2 × 1-H),
5.13 (2 H, dq, J 10.6 and 1.4, 2 × –CH=CHHꢀ), 5.31 (2 H, dq,
J 17.0 and 1.6, 2 × –CH=CHHꢀ), 5.98 (2 H, dddd, J 17.0, 10.6,
6.0 and 5.0, 2 × –CH=CH2); dC (125 MHz, C6D6, C6D6 = 128.
ppm) 19.1 (q, 2 × C-6), 26.4 (t, 2 × –O–CH2–CH2–), 46.9 (t, 2 ×
C-2), 67.2 (t, 2 × –O–CH2–CH2–), 69.4 (d, 2 × C-5), 72.4 (t, 2 ×
–CH2–CH=), 85.0 (d, 2 × C-4), 98.6 (d, 2 × C-1), 116.8 (t, 2 ×
–CH=CH2), 135.2 (d, 2 × –CH=CH2), 202.2 (s, 2 × C-3).
a
b
3.8–3.9 (3 H, m, –O–CHHꢀ–CH= , –O–CHHꢀ–CH= , 5-Ha),
3.91 (1 H, dq, J 9.5 and 6.1, 5-Hb), 4.01 (1 H, dd, J 12.7 and 5.3,
–O–CHHꢀ–CH= ), 4.32 (1 H, m, 3-Hb), 4.38 (1 H, dd, J 12.3
b
and 5.4, –O–CHHꢀ–CH= ), 4.50 (1 H, m, 3-Ha), 4.51 (1 H, d, J
a
3.0, 1-Ha), 4.65 (1 H, d, J 2.8, 1-Hb), 5.11 (1 H, dq, J 10.7 and
1.4, –CH=CHHꢀa), 5.15 (1 H, dq, J 10.5 and 1.6, –CH=CHHꢀb),
5.26 (1 H, dq, J 17.2 and 1.6, –CH=CHHꢀa), 5.33 (1 H, dq, J
17.1 and 1.6, –CH=CHHꢀb), 5.83 (1 H, dddd, J 17.1, 10.7, 5.4
a
and 5.4, –CH=CH2 ), 5.97 (1 H, dddd, J 17.1, 10.5, 6.4 and 5.3,
–CH=CH2 ), 6.00 (1 H, dd, J 90.9 and 8.1, 15NHb), 8.08 (1 H,
b
dd, J 92.2 and 9.2, 15NHa); dC (125 MHz, C6D6, C6D6 = 128.06
ppm) 18.5 and 18.6 (2 × q, C-6a,b), 26.6 and 27.1 (2 × t, 2 ×
–O–CH2–CH2–), 32.9 (t, C-2a), 35.4 (t, C-2b), 43.8 and 43.9 (2 ×
d, C-3a), 49.7 and 49.8 (2 × d, C-3b), 63.6 (d, C-5a), 67.1 and 67.8
(2 × t, 2 × –O–CH2–CH2–), 68.2 and 68.2 (2 × d, C-5b), 70.61
(t, –CH2–CH= ), 73.4 (t, –CH2–CH= ), 78.3 (d, C-4a), 82.1 and
a
b
82.2 (2 × d, C-4b), 96.5 and 96.5 (2 × d, C-1b), 96.9 and 97.0
a
b
(2 × d, C-1a), 117.2 and 117.3 (2 × t, –CH=CH2 , –CH=CH2 ),
a
b
135.0 and 135.3 (2 × d, –CH=CH2 , –CH=CH2 ), 156.5 and
156.7 (2 × s, 2 × COCF3); LC-MS (ESI) (+c): m/z (%): 645.15
(100) [M + Na]+.
3rd fraction. 19 (20 mg, 46 lmol, 5.6%); the cyanide free
a
pyran is labelled with the letter while the cyanide containing
b
pyran is labelled as ; dH (500 MHz, C6D6, C6D6 = 7.16 ppm)
[15N]2-1,4-Di-(4ꢀ-O-allyl-2ꢀ,3ꢀ,6ꢀ-trideoxy-3ꢀ-trifluoroacetamido-
a-L-ribo-hexopyran-osyl)-1,4-butanediol (15) [15N]2-1-(4ꢀ-O-
allyl-2ꢀ,3ꢀ,6ꢀ-trideoxy-3ꢀ-trifluoroacetamido-a-L-ribo-hexo-
pyranosyl)-4-(4ꢀ-O-allyl-2ꢀ,3ꢀ,6ꢀ-trideoxy-3ꢀ-trifluoroacetamido-
a-L-arabino-hexopyranosyl)-1,4-butanediol 18 and macrocycle
(19)
The bisulose 17 (350 mg, 0.82 mmol), [15N]-ammonium acetate
(700 mg, 9.0 mmol) and NaBH3CN (105 mg, 1.64 mmol) were
stirred in methanol (100 ml) for 24 h, followed by the addition
1.34 (3 H, d, J 6.3, 6-Hb), 1.45 (1 H, m, –O–CH2–CHHꢀ–b), 1
52 (2 H, m, –O–CH2–CH2–a), 1.54 (3 H, d, J 6.1, 6-Ha), 1.65
(1 H, m, –O–CH2–CHHꢀ–b), 1.78 (1 H, ddt, J 14.1, 3.7 and 3.7,
2-Heqa), 1.94 (1 H, ddd, J 13.7, 5.7 and 3.9, 2-Heqb), 2.46 (1 H,
dd, J 14.1 and 2.9, 2-Haxa), 2.48 (1 H, br d, J 13.7, 2-Haxb),
3.01 (1 H, ddd, J 9.6, 4.0 and 4.0, 4-Ha), 3.09 (1 H, ddd, J 9.4,
7.0 and 2.1, –O–CHHꢀ–CH2–b), 3.17 (1 H, m, –O–CHHꢀ–CH2–
a), 3.22 (1 H, dd, J 9.6 and 1.3, 4-Hb), 3.53 (1 H, ddd, J 9.2,
7.6 and 3.3, –O–CHHꢀ–CH2–a), 3.72 (1 H, ddd, J 9.7, 8.4 and
3 4 5 4
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6

View Article Online
1.7, –O–CHHꢀ–CH2–b), 3.91 (1 H, m, 3-Ha), 4.05 (2 H, m, –O–
C-3), 63.6 (d, 6 × C-5), 67.3 (t, 6 × –O–CH2–CH2–head), 69.7
(t, 6 × –O–CH2–CH2–tail), 79.2 (d, 6 × C-4), 96.8 (d, 6 × C-1),
117.2 (q, J 288.8, 6 × COCF3), 156.5 (q, J 35.9, 6 × COCF3);
LC-MS (ESI) (+c): m/z (%): 1811.18 (100) [M + Na]+.
a
b
CHHꢀ–CH= , –O–CHHꢀ–CH= ), 4.30 (1 H, dq, J 9.6 and 6.1,
5-Ha), 4.33 (1 H, dq, J 9.6 and 6.3, 5-Hb), 4.42 (1 H, d, J 3.9,
a
1-Hb), 4.49 (1 H, ddt, J 12.7, 5.2 and 1.5, –O–CHHꢀ–CH= ),
b
4.70 (1 H, ddt, J 12.3, 5.3 and 1.5, –O–CHHꢀ–CH= ), 4.70 (1 H,
The macrocylces were first prepared from [14N]2-15. Isolated
yields were almost identical to those described for the 15N-
labelled macrocycles ([14N]-22 = 44%; [14N]-23 = 4.5%).
dd, J 81.6 and 9.3, 15NH), 4.76 (1 H, d, J 3.7, 1-Ha), 5.16 (1 H,
dq, J 10.5 and 1.6, –CH=CHHꢀa), 5.22 (1 H, dq, J 10.4 and 2.0,
–CH=CHHꢀb), 5.35 (1 H, dq, J 17.2 and 1.7, –CH=CHHꢀa),
5.47 (1 H, dq, J 17.3 and 1.5, –CH=CHHꢀb), 5.94 (1 H, ddt, J
Preparation of spacer-linked cyclotetraristosamine 2 by
N-deacylation
a
17.2, 10.5 and 5.2, –CH=CH2 ), 6.29 (1 H, dddd, J 17.3, 10.4,
b
6.2 and 5.3, –CH=CH2 ); dC (125 MHz, C6D6, C6D6 = 128 ppm)
17.9 (q, C-6b), 18.7 (q, C-6a), 28.7 (t, –O–CH2–CH2–a), 29.1 (t,
–O–CH2–CH2–b), 36.4 (t, C-2a), 41.4 and 41.5 (2 × t, C-2b),
49.3 and 49.4 (2 × d, C-3a), 57.5 and 57.6 (2 × s, C-3b), 63.9
and 64.0 (2 × d, C-5a, C-5b), 68.5 (t, –O–CH2–CH2–a), 68.7 (t,
The hydrogenated product 22 (130 mg, 0.109 mmol) was
dissolved in THF–1.0 M aqueous NaOH (1 : 3, 72 ml) and
methanol (20 ml) was added in order to obtain a clear solution.
This mixture was allowed to stir at rt for 20 h, at which time TLC
(CH3CN–25% aqueous NH3 10 : 1, Rf 0.5 [TLC was exposed
over an aq. ammonia bath prior to use]) indicated that the
deprotection step was complete. The mixture was extracted with
CH2Cl2 (3 × 50 ml), the organic phase dried over Na2SO4 and
evaporated under reduced pressure. The amine was lyophilized
from benzene to yield macrocycle 2 (88 mg, 0.109 mmol, >99%)
as a hygroscopic gray crystalline powder.
b
a
–O–CH2–CH2–b), 71.5 (t, –CH2–CH= ), 74.7 (t, –CH2–CH= ),
81.9 and 82.0 (2 × d, C-4a), 87.1 (d, C-4b), 96.2 (d, C-1b), 98.4
(d, C-1a), 116.5 (t, –CH=CH2 ), 116.6 (t, –CH=CH2 ), 122.3 (s,
a
b
a
b
C≡N), 135.1 (d, –CH=CH2 ), 136.6 (d, –CH=CH2 ); LC-MS
(ESI) (+c): m/z (%): 438.26 (100) [M + H]+.
Macrocyclization of 15N-labelled bisallylated homodimer 15 and
catalytic hydrogenation: Synthesis of macrocycles 22 and 23
[a]2D5 = −139.9◦ (c 1 in CHCl3); in the following text the term
head
tail
refers to linker attached at C-1 while the label
refers to
The bisallylated aminodeoxysaccharide 15 (150 mg, 0.24 mmol)
was dissolved in dry CH2Cl2 (150 ml) and Grubbs’ catalyst 10
(100 mg, 20 mol%) was added in one portion. After the reaction
mixture was stirred under N2 at rt for seven days the solvent was
removed under reduced pressure. The mixture of crude products
was directly hydrogenated with H2 (1 bar) in ethyl acetate (5 ml)
using PtO2 (7 mol%). After 12 h at rt the reaction mixture
was filtered and concentrated in vacuo to yield two macrocycles
after column chromatography (silica gel; petroleum ether–ethyl
acetate 5 : 1).
butanediol linker attached at C-4; dH (500 MHz, C6D6, C6D6
= 7.16 ppm) 1.41 (12 H, d, J 6.0, 4 × 6-H), 1.54 (16 H, m,
4 × –O–CH2–CH2–tail, 4 × –O–CH2–CH2–head), 1.64 (4 H, ddd,
J 14.1, 4.7 and 3.7, 4 × 2-Heq), 2.10 (4 H, br d, J 14.1, 4 ×
2-Hax), 2.77 (4 H, dd, J 9.3 and 3.0, 4 × 4-H), 3.08 (8 H, m, 4 ×
–O–CHHꢀ–CH2–head, 4 × –O–CHHꢀ–CH2–tail), 3.25 (4 H, br s,
4 × 3-H), 3.39 (4 H, m, 4 × –O–CHHꢀ–CH2–head), 3.62 (4 H, m,
4 × –O–CHHꢀ–CH2–tail), 3.98 (4 H, dq, J 9.3 and 6.0, 4 × 5-H),
4.63 (4 H, d, J 3.7, 4 × 1-H); dN (50 MHz, C6D6, CH3NO2 = 0
ppm) −360.81 (s, 4 × NH); dC (125 MHz, C6D6, C6D6 = 128.06
ppm) 18.7 (q, 4 × C-6), 27.5 (t, 4 × –O–CH2–CH2–tail), 27.8 (t,
4 × –O–CH2–CH2–head), 34.9 (t, 4 × C-2), 45.9 (d, 4 × C-3),
62.1 (d, 4 × C-5), 67.7 (t, 4 × –O–CH2–CH2–tail), 68.9 (t, 4 ×
–O–CH2–CH2–head), 82.7 (d, 4 × C-4), 97.8 (d, 4 × C-1); LC-MS
(ESI) (+c): m/z (%): 809.54 (90) [M + H]+, 831.49 (100) [M +
Na]+; HR-MS C40H7715N4O12: calcd. 809.5419, found 809.5403.
1st fraction. 22 (65 mg, 54.3 lmol; 45%); [a]2D5 = −115.6◦ (c 1
in CHCl3); the term head refers to linker attached at C-1 while the
label tail refers to butanediol linker attached at C-4; dH (500 MHz,
C6D6, C6D6 = 7.16 ppm) 1.28 (12 H, d, J 6.0, 4 × 6-H), 1.2 − 1.6
(16 H, m, 4 × 2-H, 4 × –O–CH2–CH2–head), 1.66 (8 H, m, 4 ×
–O–CH2–CH2–tail), 2.66 (4 H, ddd, J 9.4, 3.8 and 3.3, 4 × 4-H),
2.94 (4 H, m, 4 × –O–CHHꢀ–CH2–head), 3.08 (4 H, m, 4 × –O–
CHHꢀ–CH2–tail), 3.51 (4 H, m, 4 × –O–CHHꢀ–CH2–head), 3.63 (4
H, dq, J 9.4 and 6.0, 4 × 5-H), 3.82 (4 H, m, 4 × –O–CHHꢀ–
CH2–tail), 4.35 (4 H, br s, 4 × 1-H), 4.40 (4 H, br dd, J 8.0 and 3.3,
4 × 3-H), 7.84 (4 H, dd, J 91.8 and 9.3, 4 × NH); dN (50 MHz,
C6D6, CH3NO2 = 0 ppm) −266.56 (d, J = 91.8 Hz, 4 × NH);
dC (125 MHz, C6D6, C6D6 = 128 ppm) 18.4 (q, 4 × C-6), 27.2 (t,
4 × –O–CH2–CH2–head), 27.7 (t, 4 × –O–CH2–CH2–tail), 32.9 (t,
4 × C-2), 44.1 and 44.2 (2 × d, 4 × C-3), 63.8 (d, 4 × C-5), 67.5
(t, 4 × –O–CH2–CH2–head), 70.2 (t, 4 × –O–CH2–CH2–tail), 79.3
(d, 4 × C-4), 96.9 (d, 4 × C-1), 117.2 (q, J 288.7, 4 × COCF3),
156.67 (q, J 35.9, 4 × COCF3); LC-MS (ESI) (+c): m/z (%):
1215.45 (100) [M + Na]+; HR-MS C48H7215N4O16 +Na: calcd.
1215.4531, found 1215.4532.
Preparation of spacer-linked cyclohexaristosamine 24 by
N-deacylation
The hydrogenated product 23 (11 mg, 6.2 lmol) was dissolved
in a mixture of THF–1.0 M aqueous NaOH (1 : 3, 10 ml) and
methanol (5 ml) was added in order to obtain a clear solution.
This mixture was allowed to stir at rt for 20 h, at which time
TLC (CH3CN–25% aqueous NH3 10 : 1, Rf 0.5 [TLC was
exposed over an aq. ammonia bath prior to use]) indicated that
the deprotection was complete. The mixture was extracted with
CH2Cl2 (3 × 10 ml), the organic phase was dried (Na2SO4) and
evaporated under reduced pressure. The amine was lyophilized
from benzene to yield macrocycle 24 (7.4 mg, 6.1 lmol, 99%) a
hygroscopic gray crystalline powder.
2nd fraction. 23 (7 mg, 4 lmol, 5%); in the following text
[a]2D5 = −112.3◦ (c 0.3 in CHCl3); in the following text the
term head refers to linker attached at C-1 while the label tail refers
to butanediol linker attached at C-4; dH (500 MHz, C6D6, C6D6
= 7.16 ppm) 1.43 (18 H, d, J 6.2, 6 × 6-H), 1.2–1.8 (30 H, m,
6 × –O–CH2–CH2–tail, 6 × –O–CH2–CH2–head, 6 × 2-Heq), 2.12
(6 H, br d, J 14.0, 6 × 2-Hax), 2.79 (6 H, dd, J 9.5 and 3.1,
6 × 4-H), 3.12 (12 H, m, 6 × –O–CHHꢀ–CH2–head, 6 × –O–
CHHꢀ–CH2–tail), 3.27 (6 H, br s, 6 × 3-H), 3.40 (6 H, m, 6 ×
–O–CHHꢀ–CH2–head), 3.61 (6 H, m, 6 × –O–CHHꢀ–CH2–tail),
4.01 (6 H, dq, J 9.5 and 6.2, 6 × 5-H), 4.65 (6 H, d, J 3.7, 6 × 1-
H); dN (50 MHz, C6D6, CH3NO2 = 0 ppm) −360.77 (s, 6 × NH);
dC (125 MHz, C6D6, C6D6 = 128.06 ppm) 18.7 (q, 4 × C-6), 27.3
(t, 4 × –O–CH2–CH2–tail), 27.6 (t, 4 × –O–CH2–CH2–head), 35.0
(t, 4 × C-2), 45.9 and 45.9 (2 × d, 4 × C-3), 62.1 (d, 4 × C-5),
67.7 (t, 4 × –O–CH2–CH2–tail), 68.8 (t, 6 × –O–CH2–CH2–head),
head
tail
the term
refers to linker attached at C-1 while the label
refers to butanediol linker attached at C-4; dH (500 MHz, C6D6,
C6D6 = 7.16 ppm) 1.34 (18 H, d, J 6.2, 6 × 6-H), 1.2 − 1.5
(24 H, m, 6 × 2-H, 6 × –O–CH2–CH2–head), 1.74, 1.65 (12 H,
2 × m, 6 × –O–CH2–CH2–tail), 2.75 (6 H, ddd, J 9.6, 3.6 and
3.6, 6 × 4-H), 2.95 (6 H, m, 6 × –O–CHHꢀ–CH2–head), 3.17 (6
H, m, 6 × –O–CHHꢀ–CH2–tail), 3.48 (6 H, m, 6 × –O–CHHꢀ–
CH2–head), 3.71 (6 H, dq, J 9.6 and 6.2, 6 × 5-H), 3.90 (6 H, m,
6 × –O–CHHꢀ–CH2–tail), 4.38 (6 H, d, J 2.5, 6 × 1-H), 4.57 (6
H, br dd, J 8.4 and 3.6, 6 × 3-H), 7.90 (6 H, dd, J 92.2 and
9.2, 6 × NH); dN (50 MHz, C6D6, CH3NO2 = 0 ppm) −266.36
(d, J 92.2, 6 × NH); dC (125 MHz, C6D6, C6D6 = 128 ppm)
18.3 (q, 6 × C-6), 26.8 (t, 6 × –O–CH2–CH2–head), 26.9 (t, 6 ×
–O–CH2–CH2–tail), 32.7 (t, 6 × C-2), 43.8 and 43.9 (2 × d, 6 ×
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6
3 4 5 5

View Article Online
82.7 (d, 6 × C-4), 97.9 (d, 6 × C-1); HR-MS C60H11415N6O18:
6 (a) D. Fourmy, M. I. Rech, S. C. Blanchard and J. D. Puglisi, Science,
1996, 274, 1269–1432; (b) J. Haddad, P. K. Lakshmi, B. Llano-Sotelo,
C. Kim Jr., E. F. Azucenca, M. Liu, S. B. Vakulenko, C. S. Chow and
S. Mobashery, J. Am. Chem. Soc., 2002, 124, 3229–3237; (c) H. Wang
and Y. Tor, Angew. Chem. Int. Ed., 1998, 37, 117–120; H. Wang and
Y. To r , Angew. Chem. Int. Ed., 1998, 37, 109–111; (d) D. J. Earnshaw
and M. J. Gait, Nucleic Acids Res., 1998, 26, 5551–5561.
7 (a) T. K. Stage, K. J. Hertel and O. C. Uhlenbeck, RNA, 1995,
1, 95–101; (b) H. Wang and Y. Tor, J. Am. Chem. Soc., 1997,
119, 8734–8735; (c) B. Clouet-d’Orval, T. K. Stage and O. C.
Uhlenbeck, Biochemistry, 1995, 34, 11186–11190; (d) T. Hermann
and E. Westhof, J. Mol. Biol., 1998, 276, 903–912; (e) D. J. Earnshaw
and M. J. Gait, Nucleic Acids Res., 1998, 26, 5551–5561; (f) A. Krebs,
V. Ludwig, O. Boden and M. W. Goebel, ChemBioChem, 2003, 4,
972–978.
calcd. 1213.8090, found 1213.8068.
Acknowledgements
This work was supported by the Deutsche Forschungsgemein-
schaft (SFB 416, project B2) and by the Fonds der Chemischen
Industrie. We thank Solvay Pharmaceutical Research Labora-
tories (Hannover) for donation of chemicals.
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3 4 5 6
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 3 4 4 8 – 3 4 5 6