Preparation of the tri-arabino di-mycolate fragment of mycobacterial arabinogalactan from defined synthetic mycolic acids

Article abstract of DOI:10.1016/j.carres.2016.11.006

An efficient synthetic approach to tri-arabino di-mycolates, using structurally defined synthetic α-, keto and methoxy mycolic acids is described.

Full text of DOI:10.1016/j.carres.2016.11.006

Carbohydrate Research 437 (2017) 36e42
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Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Preparation of the tri-arabino di-mycolate fragment of mycobacterial
arabinogalactan from defined synthetic mycolic acids
Mohsin O. Mohammed 1, Juma'a R. Al Dulayymi, Mark S. Baird*
School of Chemistry, Bangor University, Bangor, Wales, LL57 2UW, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient synthetic approach to tri-arabino di-mycolates, using structurally defined synthetic a-, keto
and methoxy mycolic acids is described.
Received 4 October 2016
Received in revised form
7 November 2016
© 2016 Elsevier Ltd. All rights reserved.
Accepted 7 November 2016
Available online 10 November 2016
Keywords:
Mycobacteria
Tuberculosis
Mycolyl-arabinogalactan
Mycolic acids
Glycolipids
1. Introduction
arabino-mycolate from the cell wall of Mycobacterium bovis using
organic solvent [8]. Azuma et al. reported the isolation of arabinose
mycolate under acidic conditions [9]. The structure of the mycolyl-
arabinogalactan complex of M. tuberculosis was reinterpreted using
mass spectrometry and NMR spectroscopy [10,11]. Synthetic
arabino-furanosyl oligosaccharides, including a branched penta-
saccharide were reported in 1998 [12,13]. In 2005, the prepara-
tion of a tetra-mycolylpentaarabinose (1) (Fig. 1) using a complex
natural mixture of MAs was described [14]. However, only in 2010
were structural studies of the composition of the arabinose myco-
lates of the cell wall of M. bovis reported [15]. Ishiwata et al. re-
ported the synthesis of a series of mono- (3), di- and tetra-
arabinomycolates (1) found at the terminal position of the cell
wall skeleton of BCG from M. bovis, using natural MA mixtures
Tuberculosis (TB) is one of the world's deadliest diseases and is
caused by Mycobacterium tuberculosis, which has a single known
host (man) [1,2]. The air-borne nature of this bacterium makes the
disease highly infectious, and the World Health Organization
(WHO) has reported that one third of the world's population is
probably infected with latent TB, and that there is a new case every
second [3]. The mycobacterial cell wall has a complex structure
made up of lipids, glycolipids, polysaccharides and proteins [4].
There has been growing interest in the construction of D-arabino-
oligosaccharides related to mycobacterial cell wall components,
arabino-galactan, lipoarabinomannan and arabinomannan from
M. tuberculosis [5]. The mycolyl-arabinogalactan (mAG) complex is
the largest component structure and forms from cross bonding
between both D-arabinofuranosyl (Araf) and galactofuranosyl
extracted from cells. All of the compounds showed strong TNF-
a
inducing activity in vitro. Such arabinose mycolates have also been
reported to show anti-cancer properties [6]. The mechanism of the
activity of arabinomycolates is not clear [14].
Although a methoxy trisaccharide of arabinofuranose 2 (Fig. 1)
has been prepared and used in an acylation reaction with fatty acids
such as behenic acid, palmitic acid and butyric acid [16], there are
no examples of the synthesis of arabinofuranose oligosaccharides
esterified with structurally defined complete synthetic mycolic
acids (MAs) which are the main components of the cell wall of
(Galf) with a long-chain
a-alkyl-branched b-hydroxylated fatty
acid, ‘mycolic acid’ (MA) [6]. The complex lipids and poly-
saccharides within the cell wall of M. tuberculosis are assumed to be
the cause of its characteristic pathogenesis [7].
Anderson and Geiger in 1937 reported the first extraction of
* Corresponding author.
E-mail address: m.baird@bangor.ac.uk (M.S. Baird).
Current address: College of science, Chemistry department, Kirkuk University,
M. tuberculosis [6]. MAs 4 are
b-hydroxy fatty acids with a long a-
1
alkyl side chain (Fig. 2) [17,18].
Iraq.
http://dx.doi.org/10.1016/j.carres.2016.11.006
0008-6215/© 2016 Elsevier Ltd. All rights reserved.

M.O. Mohammed et al. / Carbohydrate Research 437 (2017) 36e42
37
Scheme 1. Reagents and conditions: (a) Ac2O, pyridine, 0 ꢁC, 7 (R ¼ Ac) 80%; (b) TolSH
(1.2 equiv.), BF3.Et2O (5.1 equiv.), CH2Cl2, 0 ºC/RT, 8 h, 8 (R ¼ Ac), 65%, (c) NaOCH3 (5
equiv.), CH3OH, RT, 3 h, 8 (R ¼ H), 90%; (d) t-BuPh2SiCl (1.5 equiv), imidazole, DMF, 0 ºC/
RT, 16 h, 82%; (e) BzCl (4.6 equiv.), pyridine, 0 ºC/RT, 2 h, 83%.
esterified to give triacetate 7 (R ¼ Ac) [22]. Condensation of this
with p-thiotoluene in the presence of boron trifluoride etherate
afforded 8 (R ¼ Ac), which on reaction with NaOCH3 in methanol
afforded thioglycoside triol 8 (R ¼ H). Protection of the primary
alcohol as a silyl ether followed by benzoylation of the secondary
alcohols gave 5.
The initial step in the synthetic route to acceptor 6 [23], the
separation of the two anomers of 7 (R ¼ H), was carried out using
two methods (Supplementary data, Schemes 1 and 2).
Liu et al. [16] have reported the coupling of the mono-saccharide
building blocks to prepare the trisaccharide through the reaction of
a 2-O-benzylated glycosyl acceptor and thioglycoside 5 using silver
trifluoromethane sulfonate and N-iodosuccinimide in dry CH2Cl2.
In the present work, the benzoylated glycosyl acceptor 6 and thi-
oglycoside 5 were reacted under the reported conditions (Scheme
2). Trisaccharide 9a was obtained as a single stereoisomer in 87%
yield, which is similar to that reported for the benzyl compound
[16]. The product showed the expected three acetal signals in the
Fig. 1. Structure of targets of mycoloyl-arabinans.
proton NMR spectrum, two broad singlets at
newly formed -glycosidic links, and a third singlet at 5.56; these
correlated by HSQC with three signals in the carbon spectrum for
the glycosidic links at 107.0, 106.0 and 105.3 respectively. Com-
d 5.10 and 5.33, for the
a
d
pound 9a was deprotected with sodium methoxide to give 9b as a
thick oil in 81% yield. This was benzylated to protect the five sec-
ondary hydroxyl groups using benzyl bromide and sodium hydride
in dry DMF to give 9c. Desilylation of the two primary hydroxyl
groups gave 10a. Direct esterification of the primary hydroxyl group
of Araf with a carboxyl group in natural mycolic acid mixtures has
been achieved in a low yield (30%) [14], while activating the sugar
as a tosylate raised the yield to 79%. Therefore, the two hydroxyl
groups in compound 10a were tosylated using p-toluenesulfonyl
chloride in dry pyridine in the presence of catalytic 4-
dimethylaminopyridine to afford the tosylate 10b (Scheme 2).
The next step was the coupling of trisaccharide 10b with the
structurally defined synthetic mycolic acids, which had been pre-
pared earlier [27e29]. Firstly, a model tri-arabino-di mycolate was
prepared by coupling tosylate 10b with palmitic acid through the
alkylative esterification strategy using cesium hydrogen carbonate
in dry DMF: THF at 70 ꢁC for four days [14], to give compound 11a,
which was then debenzylated to give compound 12a (Scheme 3).
The synthesis of this glycolipid has been reported using a different
method. Data obtained for 12a was identical to that reported [16].
A series of triarabino-dimycolates were then prepared according
to the above procedure; the structures of the mycolic acid moieties,
Fig. 2. Generalised MA structure and arabinose building blocks.
MAs in M. tuberculosis have 80e90 carbons, compared to those
from corynebacterium (30e36 carbons), Rhodococcus (34e38 car-
bons) and Nocardia (46e60 carbons) [19,20]. Natural mixtures
extracted from mycobacteria consist of many individual MA con-
taining a range of functional groups, X and Y, including cis- and
trans-cyclopropanes, cis- and trans-alkenes, methoxy and keto
fragments, and different chain lengths [21].
The aim of this study was to synthesize a series of dimycolated
triarabinoses (2), comprising single defined synthetic mycolic acids,
in order that the selectivity of their immune stimulatory activity,
e.g. in inducing Interleukin 6 (IL-6) and tumor necrosis factor alpha
(TNF-a), could be evaluated.
2. Results and discussion
2.1. Synthesis of trisaccharides
including a-, methoxy- and keto-classes are shown in Scheme 3. In
each case, the products the proton NMR spectra included the ex-
pected three characteristic broad single-hydrogen singlets for the
The target trisaccharide structure 2 has two a-glycosidic link-
ages, which can be assembled readily from known building blocks,
donor 5 [22] and acceptor 6 [23]. The route to the 2,3-O-benzoyl-
protected thioglycosyl donor 5 was slightly modified compared to
the literature method (Scheme 1) [22]. D-(ꢀ)-Arabinose was
treated with HCl, freshly prepared by addition of acetyl chloride to
anhydrous methanol at 0 ꢁC. Work up with pyridine rather than
acetal hydrogens in the region
d 4.9e5.2.
2.2. IL-6 and TNF-
compounds
a secretion assays with the synthesized
ammonium carbonate [24], gave methyl-
predominant formation of the -anomer (
Rather than esterifying with benzoate, the mixture was directly
a
,
b
-D-Araf, 7 (R ¼ H), with
a
a
/b
-D, 3:2) [25,26].
Ishiwata et al. reported the synthesis of a series of mono-, di-
and tetra-arabinomycolates found in the terminal position of the

38
M.O. Mohammed et al. / Carbohydrate Research 437 (2017) 36e42
Scheme 2. Reagents and conditions: (a) NIS, AgOTf, (9a, 87%); (b) NaOCH3 (cat.), CH3OH, rt, 2 h, (9b, 86%); (C) NaH, BnBr, DMF, 0 ºC/rt 16 h, (9c, 79%); (d) TBAF, THF, 0 ºC/rt, 16 h (10a
77%); (e) TsCl, pyridine, DMAP, CH2Cl2 at 0 ꢁC (10b, 74%).
Scheme 3. Reagents and conditions: (i) CsHCO3, THF-DMF, 4 days, 70 ꢁC; (ii) Pd(OH)2, H2, CH2Cl2-MeOH, RT, overnight.
cell-wall skeleton of bacillus calmette Guerin from M. bovis, by
showed they differentially induce TNF-
a secretion in a murine
using natural mycolic acid mixtures extracted from the cell wall and
macrophage cell line, some at levels similar to trehalose dimycolate

M.O. Mohammed et al. / Carbohydrate Research 437 (2017) 36e42
39
(TDM) [14]. Arabino-mycolates obtained by acid hydrolysis from
the originally prepared CWS (SMP-105) of M. bovis BCG Tokyo 172,
consisting mainly of mono-arabinose mono-mycolate, penta-
arabinose tetra-mycolate and hexa-arabinose tetra-mycolate frac-
(2H, m), 4.18 (1H, br. d, J 1.8 Hz), 4.12 (2H, br. d, J 3.8 Hz), 4.05e4.02
(4H, m), 4.01e3.95 (2H, m), 3.80 (1H, dd, J 11.4, 2.3 Hz), 3.77e3.73
(2H, m), 3.70 (2H, br. d, J 11.3 Hz), 3.34 (3H, s), 3.01e2.70 (4H, m),
1.10e0.99 (18H, m); dC (101 MHz, CDCl3 þ few drops CD3OD): 135.7,
135.6, 135.5, 129.5, 128.3, 128.0, 127.9, 127.8, 109.1, 108.6, 108.4, 88.0,
87.4, 83.8, 82.4, 79.3, 78.9, 78.4, 77.8, 77.7, 66.1, 64.0, 63.85, 54.8,
tions, significantly induced TNF-a production with an intensity
comparable to that of cell-wall skeleton, a potent adjuvant, and
enhanced delayed type per sensitivity reactions against inactivated
26.7, 26.6; nmax: 3445, 3010, 2928, 2860, 1494, 1050, 824 cmꢀ1
.
tumor cells. The induced TNF-
a
production was completely
(c) Compound 9b (0.2 g, 0.2 mmol) in dry DMF:THF(1:1) (4 mL)
was added dropwise (1 drop each 10 s) to a stirred suspension of
NaH (0.1 g, 8.3 mmol) (60% w/w, dispersion in mineral oil, washed
with petrol three times) at r. t. under nitrogen. The mixture was
stirred for 30 min then benzyl bromide (0.1 mL, 0.8 mmol) in dry
DMF (1 mL) was added, stirred at r. t. for 16 h, then quenched by
slow addition of methanol (3 mL), and water (10 mL). The organic
layer was separated and the aqueous layer was re-extracted with
ethyl acetate (2 ꢃ 50 mL). The combined organic layers were
washed with water (20 mL) and brine (20 mL), dried and the sol-
vent evaporated under reduced pressure. Column chromatography
on silica eluting with petrol/ethyl acetate (5:1) gave the title
compound as a thick oil (0.23 g, 77%) [Found (MALDI) (M þ Na)þ:
dependent on TLR2 and MyD88 pathways [6]. To provide an initial
evaluation of the activities of synthesized tri-arabino di-mycolates
reported here (12c and 12f) as immune potentiators, secretion
inducing assays for IL-6 and TNF-a, cytokines involved in inflam-
mation, were conducted, in comparison with TDM and synthetic
mono-arabino mono-mycolates [30]. Surprisingly, neither com-
pound was strongly stimulatory in either assay when compared to
synthetic TDMs, trehalose monomycolates or arabinose mycolates
[31,32]. Further work to evaluate the biological effects of these
molecules is under way.
3. Experimental section
1377.0, C83H94NaO13Si2, requires: 1377.6], ½a D22
þ40 (c 0.1, CHCl3)
ꢂ
For general experimental detail, see Supplementary
Information. Unless otherwise stated, all products were single
components by TLC and by proton and carbon NMR.
which showed dH (400 MHz, CDCl3): 7.66e7.51 (7H, m), 7.42e7.17
(38H, m), 5.19 (1H, s), 5.17 (1H, s), 4.94 (1H, s), 4.59e4.37 (10H, m),
4.28 (1H, dd, J 6.3, 2.3 Hz), 4.22e4.14 (2H, m), 4.14e4.03 (5H, m),
4.03e3.95 (2H, m), 3.86e3.74 (5H, m), 3.37 (3H, s), 1.03 (18H, s); dC
(101 MHz, CDCl3): 135.7, 135.65, 135.62, 135.6, 129.6, 129.54, 129.51,
128.5, 128.4, 128.35, 128.34, 128.3,128.22, 128.2,127.9, 127.8, 127.79,
127.75, 127.73, 127.66, 127.63, 127.6, 127.56, 127.53, 127.4, 127.35,
127.33, 127.3, 127.28, 107.2, 106.5, 105.4, 88.5, 88.3, 88.0, 83.1, 82.8,
82.3, 81.8, 81.2, 80.4, 72.0, 71.9, 71.73, 71.7, 71.6, 66.2, 63.5, 63.3,
54.7, 26.8, 26.7; nmax: 3466, 3050, 3017, 2958, 2930, 2858, 1493,
3.1. Methyl 2,3-di-O-benzyl-5-O-p-toluenesulfonyl-
furanosyl-(1 / 3)-[2,3-di-O-benzyl-5-O-p-toluene- sulfonyl-
arabinofuranosyl-(1 / 5)]-2-O-benzyl- -D-Araf 10b
a-D-arabino-
a-D-
a
(a) Molecular sieves 4 Å (6.6 g) were added to a stirred solution
of the acceptor 6 (0.9 g, 3.3 mmol) and the donor 5 (6.0 g, 8.5 mmol)
in dry CH2Cl2 (30 mL) at r. t. under a nitrogen atmosphere. The
reaction mixture was stirred for 30 min then cooled to -60 ꢁC and
N-iodosuccinimide (2.09 g, 9.29 mmol) was added followed by the
addition of AgOTf (0.36 g, 1.40 mmol). The mixture was stirred at
the same temperature until the color became red/dark brown and
TLC showed no starting material, then it was quenched by the
addition of triethylamine (1 mL) until it turned yellow. The mixture
was diluted with CH2Cl2 (100 mL) and filtered through celite and
the solvent was evaporated under reduced pressure. Column
chromatography on silica eluting with hexane/ethyl acetate (5:1)
gave compound 9a as a thick oil (4.2 g, 87%) [Found (MALDI)
1112, 701 cmꢀ1
.
(d) Tetrabutylammonium fluoride (0.3 mL, 0.3 mmol, 1 M) was
added dropwise to a stirred solution of 9c (0.2 g, 0.147 mmol) in dry
THF (10 mL) at 0 ꢁC under nitrogen atmosphere. The mixture was
allowed to reach r. t. and stirred for 16 h then the solvent was
evaporated under reduced pressure to give an oil which was pu-
rified by column chromatography on silica eluting with hexane/
ethyl acetate (1:1) to give compound 10a as a colourless thick oil
(0.1 g, 77%) [Found (MALDI) (M þ Na)þ: 901.3, C51H58NaO13, re-
quires: 901.3], ½a D20
þ90 (c 0.1, CHCl3), which showed dH (400 MHz,
ꢂ
CDCl3): 7.38e7.21 (25H, m), 5.16 (1H, s), 5.12 (1H, d, J 1.2 Hz), 4.96
(1H, d, J 1.2 Hz), 4.61e4.42 (9H,m), 4.38 (1H, d, J 12.0 Hz), 4.30 (1H,
dd, J 7.4, 3.7 Hz), 4.25 (1H, ddd, J 6.3, 5.2, 2.9 Hz), 4.16e4.07 (3H, m),
4.03 (1H, dd, J 3.7, 1.2 Hz), 4.01 (1H, dd, J 3.7, 1.2 Hz), 3.95 (1H, dd, J
11.6, 3.8 Hz), 3.91 (1H, dd, J 6.6, 2.9 Hz), 3.85e3.71 (4H, m), 3.66 (1H,
dd, J 12.2, 5.2 Hz), 3.59 (1H, dd, J 12.2, 5.8 Hz), 3.40 (3H, s), 2.84 (1H,
br. s), 2.48 (1H, br. s); dC (101 MHz, CDCl3): 137.7, 137.6, 137.4, 137.3,
137.2, 128.5, 128.44, 128.43, 128.4, 128.38, 127.96, 127.94, 127.9,
127.87, 127.83, 127.8, 127.71, 106.9, 106.2, 105.8, 88.7, 88.2, 87.5, 83.0,
82.9, 82.3, 81.9, 80.9, 79.7, 72.3, 72.2, 72.0, 71.9, 71.8, 64.9, 62.8, 62.7,
54.9; nmax: 3467, 3050, 3017, 2926, 2861, 1609, 1494, 1050,
(M þ Na)þ: 1447.6, C83H84NaO18Si2, requires: 1447.5], ½a D20
þ16 (c
ꢂ
0.1, CHCl3) which showed dH (400 MHz, CDCl3): 8.07 (2H, d, J
7.9 Hz), 8.02e7.91 (8H, m), 7.70e7.62 (9H, m), 7.59e7.41 (8H, m),
7.40e7.28 (18H, m), 5.64 (1H, d, J 4.5 Hz), 5.61 (1H, d, J 4.2 Hz), 5.56
(1H, s), 5.57 (1H, s), 5.53 (1H, br. s), 5.41 (1H, s), 5.32 (1H, br. s), 5.10
(1H, br. s), 4.49e4.35 (4H, m), 4.08 (1H, dd, J 11.3, 5.1 Hz), 3.97 (5H,
m), 3.44 (3H, s),1.01 (9H, s), 0.98 (9H, s); dC (101 MHz, CDCl3): 165.5,
165.4, 165.2, 165.1, 135.63, 135.6, 135.5, 133.3, 133.2, 133.15, 133.1,
133.0, 129.96, 129.9, 129.8, 129.78, 129.7, 129.6, 129.4, 129.3, 129.2,
129.1, 128.4,128.31, 128.3, 128.2, 127.6, 107.0, 106.0, 105.3, 84.0, 83.4,
82.5, 82.0, 81.8, 81.6, 80.6, 77.2, 77.1, 66.1, 63.5, 63.3, 54.7, 26.7, 26.6,
19.3, 19.2; nmax: 3069, 3010, 2929, 2859, 1724, 1602, 1451, 1070,
824 cmꢀ1
.
(e) 4-Toluenesulfonyl chloride (2.82 g, 14.7 mmol) was added to
a stirred solution of 10a (1.30 g,1.47 mmol), pyridine (1.17 g,1.19 mL,
14.7 mmol) and DMAP (catalytic amount) in dry CH2Cl2 (10 mL) at
708 cmꢀ1
.
(b) A solution of sodium methoxide (2 mL, 1 M, in methanol)
was added to a stirred solution of 9a (0.20 g, 0.14 mmol) in dry
MeOH: CH2Cl2 (1:1, 5 mL) at r. t. until a pH of 11 was obtained. The
mixture was stirred at r. t. for 2 h then the solvent was evaporated
under reduced pressure to give an oil. The residue was purified by
column chromatography on silica eluting with CHCl3:MeOH (5:2)
to give 9b compound as a thick oil (0.1 g, 83%) [Found (MALDI)
0
ꢁC under nitrogen. The mixture was allowed to reach r. t. and
stirred for 16 h, then diluted with ethyl acetate (100 mL) and water
(50 mL), the organic layer was separated and the aqueous layer was
re-extracted with ethyl acetate (3 ꢃ 50 mL). The combined organic
layers were washed with water (50 mL) and brine (50 mL), dried.
The solvent was evaporated under reduced pressure to give an oil;
column chromatography on silica eluting with hexane/ethyl acetate
(1:1) afforded the title compound as a colorless thick oil 10b (1.3 g,
74%) [Found (MALDI) (M þ Na)þ: 1209.2, C65H70NaO17S2, requires:
(M þ Na)þ: 927.1, C48H64NaO13Si2, requires: 927.3], ½a D22
þ50 (c 0.10,
ꢂ
CHCl3) which showed dH (400 MHz, CDCl3 þ few drops CD3OD):
7.49e7.34 (20H, m), 5.19 (1H, s), 5.14 (1H, s), 4.86 (1H, s), 4.25e4.20

40
M.O. Mohammed et al. / Carbohydrate Research 437 (2017) 36e42
1209.3], ½a 2D2
ꢂ
þ71 (c 0.10, CHCl3) which showed dH (400 MHz,
29.62, 29.6, 29.56, 29.5, 29.4, 29.3, 29.2, 29.1, 28.6, 27.4, 27.3, 25.96,
CDCl3): 7.7 (2H, d, J 8.3 Hz), 7.8 (2H, d, J 8.4 Hz), 7.37e7.23 (29H, m),
5.09 (1H, br. s), 5.08 (1H, br. s), 4.93 (1H, s), 4.61e4.42 (9H, m), 4.35
(1H, d, J 12.0 Hz), 4.30e4.24 (1H, m), 4.22e4.10 (6H, m), 4.10e4.05
(2H, m), 4.0 (1H, dd, J 3.3, 1.2 Hz), 3.96 (1H, dd, J 3.1, 1.0 Hz), 3.87
(2H, dd, J 6.1, 3.1 Hz), 3.84 (1H, dd, J 12.0, 4.0 Hz), 3.69 (1H, dd, J 12.0,
2.5 Hz), 3.38 (3H, s), 2.38 (3H, s), 2.4 (3H, s); dC (101 MHz, CDCl3):
144.8, 144.7, 137.5, 137.4, 137.3, 137.2, 137.1, 132.7, 132.6, 129.8, 129.7,
128.4, 128.38, 128.35, 128.33, 128.3, 128.0, 127.93, 127.9, 127.85,
127.82, 127.8, 127.7, 127.69, 127.67, 106.9, 106.4, 105.5, 88.0, 87.6,
87.4, 82.8, 82.7, 80.5, 80.4, 79.0, 78.7, 72.2, 72.0, 71.8, 71.81, 71.7,
68.7, 68.6, 65.7, 54.8, 21.5; nmax: 3088, 3064, 3031, 2924, 2862,1598,
25.2, 25.2, 22.5, 15.6, 14.7, 13.9, 10.7; nmax: 3401, 2919, 2851, 1733,
1467, 1099, 720 cmꢀ1
.
3.3. Methyl 5-O-(2-[(R)-1-hydroxy-18-[(1R,2S)-2-[(17S, 18S)-17-
methoxy-18-methylhexatriacontyl]cyclopropyl]-octadecyl]-
tetracosanoate)-
hydroxy-18-[(1R,2S)-2-[(17S,18S)-17-methoxy-18-methyl-
hexatriacontyl]cyclopropyl]octadecyl]-tetracosanoate)- -D-
arabinofuranos-yl-(1 / 5)]- -D-Araf 12c
a-D-arabinofuranosyl-(1 / 3)-[5-O-(2-[(R)-1-
a
a
(a) Cesium hydrogencarbonate (0.081 g, 0.417 mmol) was added
to a stirred solution of 10b (0.050 g, 0.042 mmol) and (2R)-2-{(1R)-
1-hydroxy-18-[(2S)-2-[(17S,18S)-17-methoxy-18-
1454, 1177, 738 cmꢀ1
.
3.2. Methyl5-O-[(2R)-2-(1-hydroxy-18-[(1S,2R)-2-[(17S, 18S) -17-
methoxy-18-methylhexatriacontyl)cyclopropyl]octadecyl]-
ethylhexatriacontyl]cyclopropyl]octadecyl}tetracosanoic acid [33]
(0.113 g, 0.092 mmol) in dry DMF: THF (1:5, 6 mL) at r. t. under
nitrogen. The mixture was stirred at 70 ꢁC for 4 days, then work up
and purification as before gave 11c as a colourless thick oil (50 mg,
36%) [Found (M þ Na)þ: 3315.8808, C217H382NaO19, requires:
hexacosanoate)]-
hydroxy-18-[(1S,2R)-2-[(17S,18S)-17-methoxy-18-methylhexa-
triacontyl)-cyclopropyl]octadecyl]hexacosanoate)]- -D-arabino-
furanosyl-(1 / 5)]- -D-Araf 12b
a-D-arabinofuranosyl-(1 / 3)-5-O-[(2R)-2-(1-
a
a
3315.8818], ½a 2D3
þ40 (c 0.1, CHCl3) which showed dH (400 MHz,
ꢂ
CDCl3): 7.39e7.22 (25H, m), 5.18 (1H, s), 5.13 (1H, s), 4.91 (1H, s),
4.61e4.42 (9H, m), 4.38 (1H, d, J 12.0 Hz), 4.30e4.23 (6H, m),
4.22e4.16 (1H, m), 4.14e4.05 (2H, m), 4.03 (1H, dd, J 3.2, 1.0 Hz),
3.98 (1H, dd, J 3.2, 1.0 Hz), 3.95 (1H, dd, J 12.0, 4.6 Hz), 3.86e3.80
(2H, m), 3.78 (1H, dd, J 12.0, 2.3 Hz), 3.67e3.57 (2H, m), 3.37 (3H, s),
3.35 (6H, s), 3.01e2.92 (2H, m), 2.67 (2H, br. s), 2.45e2.37 (2H, m),
1.72e1.07 (285 H, m), 0.89 (12H, t, J 6.8 Hz), 0.86 (6H, d, J 6.9 Hz),
0.71e0.60 (4H, m), 0.61e0.53 (2H, dt, J 7.6, 4.0 Hz), ꢀ0.32 (2H, br. q, J
5.2 Hz); dC (101 MHz, CDCl3): 175.1, 174.9, 137.6, 137.51, 137.5, 137.4,
137.2, 128.45, 128.41, 128.4, 128.38, 128.37, 127.9, 127.85, 127.8,
127.74, 127.7, 107.0, 106.3, 105.5, 88.2, 87.9, 87.8, 85.4, 83.7, 83.6,
80.6, 80.4, 79.3, 79.1, 72.3, 72.2, 72.1, 72.0, 71.9, 71.7, 65.5, 63.0, 57.7,
54.8, 51.8, 51.7, 35.3, 32.4, 31.9, 30.5, 30.2, 29.98, 29.9, 29.7, 29.6,
29.5, 29.4, 28.7, 27.6, 27.4, 26.2, 22.7, 15.7, 14.8, 14.1, 10.9; nmax: 3436,
(a) Cesium hydrogencarbonate (0.065 g, 0.335 mmol) was added
to a stirred solution of 10b (0.040 g, 0.033 mmol) and (2R)-2-{1-
hydroxy-18-[(1S,2R)-2-[(17S,18S)-17-methoxy-18-
methylhexatriacontyl]cyclopropyl]octadecyl}hexacosa-noic
acid
[28] (0.092 g, 0.073 mmol) in dry DMF: THF (1:5, 3 mL) at r. t. under
a nitrogen atmosphere. The mixture was stirred at 70 ꢁC for 4 days,
then worked up and purified as before to afford 11b as a colourless
thick oil (0.051 g, 45%) [Found (MALDI) (M þ Na)þ: 3371.9,
C
221H390NaO19, requires: 3371.9], ½a D23
þ35 (c 0.1, CHCl3) which
ꢂ
showed dH (400 MHz, CDCl3): 7.37e7.23 (25H, m), 5.18 (1H, br. s),
5.13 (1H, br. s), 4.91 (1H, br. s), 4.49e4.37 (9H, m), 4.34 (1H, d, J
11.7 Hz), 4.32e4.24 (6H, m), 4.18 (1H, ddd, J 9.7, 6.3, 3.0 Hz), 4.11
(1H, dd, J 4.4, 2.7 Hz), 4.08 (1H, br. d, J 2.9 Hz), 4.00 (1H, dd, J 2.9,
0.6 Hz), 3.96 (1H, br. d, J 2.3 Hz), 3.93 (1H, dd, J 7.8, 3.9 Hz),
3.88e3.78 (2H, m), 3.76 (1H, dd, J 11.4, 1.8 Hz), 3.67e3.57 (2H, m),
3.37 (3H, s), 3.35 (6H, s), 2.99e2.93 (2H, m), 2.67 (1H, d, J 6.1 Hz),
2.65 (1H, d, J 6.5 Hz), 2.41 (2H, dt, J 9.0, 5.8 Hz),1.68e1.03 (294H, m),
0.89 (12H, t, J 6.8 Hz), 0.86 (6H, d, J 6.9 Hz), 0.71e0.61 (4H, m), 0.57
(2H, dt, J 7.6, 4.0 Hz), ꢀ0.33 (2H, br. q, J 5.1 Hz); dC (101 MHz, CDCl3):
175.1, 175.0, 137.7, 137.6, 137.5, 137.4, 137.2, 128.5, 128.41, 128.4,
127.95, 127.9, 127.8, 127.73, 127.7, 107.0, 106.3, 105.5, 88.2, 87.9, 87.8,
85.4, 83.7, 80.6, 80.4, 79.3, 79.1, 72.3, 72.2, 72.1, 71.98, 71.8, 65.6,
63.0, 57.7, 54.8, 51.9, 51.7, 35.3, 32.4, 31.9, 30.5, 30.2, 29.97, 29.9,
29.7, 29.66, 29.5, 29.4, 28.7, 27.6, 26.2, 22.7, 15.8, 14.9, 14.1, 10.9;
2920, 2851, 1733, 1734, 1174, 734 cmꢀ1
.
(b) Palladium (II) hydroxide on activated charcoal (20% Pd(OH)2-
C, 0.01 g, 0.30 fold by weight) was added to a stirred solution of
compound 11c (0.037 g, 0.010 mmol) in dry CH2Cl2: MeOH (1:1,
2 mL) at r. t. under hydrogen. After 16 h, work up and purification as
before gave the title compound 12c as a white oil (21 mg, 65%)
[Found (M
þ
Na)þ: 2865.6424, C182H352NaO19
þ24 (c 0.1, CHCl3) which showed dH (400 MHz,
,
requires:
2865.6470], ½a 1D6
ꢂ
CDCl3 þ few drops CD3OD): 5.02 (1H, d, J 1.5 Hz), 4.98 (1H, br. s),
4.80 (1H, br. s), 4.46 (1H, dd, J 11.7, 4.3 Hz), 4.37 (1H, dd, J 11.6,
4.8 Hz), 4.27 (1H, dd, J 11.7, 4.9 Hz), 4.16 (1H, dd, J 12.0, 4.8 Hz),
4.14e4.08 (2H, m), 4.08e3.99 (5H, m), 3.95e3.87 (3H, m),
3.62e3.52 (3H, m), 3.35 (3H, s), 3.31 (6H, s), 2.94e2.85 (2H, m),
2.44e2.34 (2H, m), 1.37e1.13 (292H, m), 0.85 (12H, t, J 6.8 Hz), 0.82
(6H, d, J 6.9 Hz), 0.66e0.57 (4H, m), 0.56e0.49 (2H, dt, J 7.6,
4.0 Hz), ꢀ0.37 (2H, br. q, J 5.2 Hz); dC (101 MHz, CDCl3 þ few drops
CD3OD): 175.2, 175.0, 109.1, 107.9, 107.2, 85.5, 82.9, 82.5, 82.0, 81.8,
81.0, 80.9, 79.7, 78.0, 72.5, 66.9, 65.9, 63.1, 57.6, 54.8, 52.8, 35.2, 32.3,
31.8, 30.4, 30.1, 29.8, 29.7, 29.66, 29.6, 29.5, 29.3, 29.2, 28.6, 27.4,
26.0, 22.5, 15.7, 14.7, 14.0, 10.8; nmax: 3412, 2919, 2850, 1731, 1466,
nmax: 3517, 3063, 3031, 2922, 2852, 1736, 1466, 1101, 757 cmꢀ1
.
(b) Palladium (II) hydroxide on activated charcoal (20% Pd(OH)2-
C, 12 mg, 0.3 fold by weight) was added to a stirred solution of
compound 11b (0.042 g, 0.014 mmol) in dry CH2Cl2: MeOH (1:1,
2 mL) at r. t. under a hydrogen. The mixture was stirred for 16 h,
then filtered and the solvent was evaporated under reduced pres-
sure; column chromatography on silica eluting with CHCl3:MeOH
(5:1) gave the title compound 12b as a thick oil (0.03 g, 82%) [Found
(M þ Na)þ: 2921.8, C186H360NaO19, requires: 2921.7], ½a D20
þ21 (c
ꢂ
0.10, CHCl3) which showed dH (500 MHz, CDCl3 þ few drops
CD3OD): 4.98 (1H, br. s), 4.95 (1H, br. s), 4.77 (1H, br. s), 4.40 (1H, dd,
J 11.8, 4.3 Hz), 4.33 (1H, dd, J 11.6, 4.5 Hz), 4.24 (1H, dd, J 11.6,
4.7 Hz), 4.15 (1H, dd, J 11.6, 4.3 Hz), 4.13e4.07 (2H, m), 4.07e3.94
(5H, m), 3.94e3.80 (3H, m), 3.67e3.55 (3H, m), 3.36 (3H, s), 3.32
(6H, s), 2.96e2.90 (2H, m), 2.37e2.30 (2H, m), 1.61e0.97 (301H, m),
0.82 (12H, t, J 7.0 Hz), 0.79 (6H, d, J 6.9 Hz), 0.64e0.55 (4H, m), 0.50
(2H, dt, J 8.0, 4.0 Hz), ꢀ0.39 (2H, br. q, J 5.1 Hz); dC (126 MHz,
CDCl3 þ few drops CD3OD): 175.1, 175.0, 109.1, 107.9, 107.2, 85.5,
83.0, 82.4, 81.8, 81.0, 79.8, 77.9, 72.5, 72.45, 65.9, 63.4, 63.1, 57.5,
54.8, 52.8, 50.0, 35.2, 34.8, 34.7, 32.2, 31.8, 30.3, 30.1, 29.82, 29.8,
1099, 720 cmꢀ1
.
3.4. Methyl 5-O-(2-[(R)-1-hydroxy-12-{(1R,2S)-2-(14-[(1R, 2S)-2-
eicosylcyclopropyl]tetradecyl]cyclopropyl}dodecyl)hexacosanoate)-
a
-D-arabinofuranosyl-(1 / 3)-[5-O-(2-[(R)-1-hydroxy-12-
{(1R,2S)-2-(14-[(1R,2S)-2-eicosylcyclopropyl]tetradecyl]
cyclopropyl}dodecyl)hexacosanoate)- -D-arabinofuranosyl-
(1 / 5)]- -D-Araf 12d
a
a
(a) Cesium hydrogencarbonate (0.089 g, 0.458 mmol) was added
to a stirred solution of 10b (0.055 g, 0.046 mmol) and (2R)-2-{(1R)-

M.O. Mohammed et al. / Carbohydrate Research 437 (2017) 36e42
41
1-hydroxy-12-[(1R)-2-[14-[(2S)-2-eicosyl-cyclopropyl]tetradecyl]
cyclopropyl]dodecyl}hexacosanoic acid [27] (0.115 g, 0.101 mmol)
in dry DMF: THF (1:5, 6 mL) at r. t. under hydrogen. The mixture
was stirred at 70 ꢁC for 4 days then work up and purification as
before afforded 11d as a colourless oil (56 mg, 18%) [Found
137.7, 137.5, 137.4, 137.3, 137.2, 128.5, 128.4, 128.38, 128.37, 127.95,
127.9, 127.8, 127.73, 127.7, 107.0, 106.3, 105.5, 88.2, 87.9, 87.8, 83.6,
80.6, 79.2, 79.1, 72.3, 72.2, 72.1, 72.0, 71.9, 71.7, 65.6, 63.0, 60.4, 54.8,
51.8, 51.7, 31.9, 30.2, 29.72, 29.7, 29.6, 29.5, 29.4, 28.7, 22.6, 15.8, 14.1,
10.9; nmax: 3524, 3035, 2918, 2850, 1735, 1466, 1018, 734 cmꢀ1
.
(M
þ
Na)þ: 3139.7057, C207H358NaO17, requires: 3139.7041],
2. (b) Palladium (II) hydroxide on activated charcoal (20%
Pd(OH)2-C, 8.2 mg, 0.30 fold by weight) was added to a stirred
solution of compound 11e (0.027 g, 0.008 mmol) in dry CH2Cl2:
MeOH (1:1, 2 mL) at r. t. under hydrogen. After 16 h, work up and
purification as before gave the title compound 12e as a colourless
½
a 2D3
ꢂ
þ72 (c 0.1, CHCl3) which showed dH (400 MHz, CDCl3):
7.37e7.22 (25H, m), 5.18 (1H, br. s), 5.14 (1H, br. s), 4.92 (1H, br. s),
4.61e4.43 (9H, m), 4.35 (1H, d, J 12.0 Hz), 4.32e4.25 (6H, m),
4.22e4.16 (1H, m), 4.09e4.03 (2H, m), 4.01 (1H, dd, J 3.0, 1.0 Hz),
3.97 (1H, dd, J 3.0, 1.0 Hz), 3.92 (1H, dd, J 12.0, 7.5 Hz), 3.88e3.80
(2H, m), 3.77 (1H, dd, J 12.0, 2.2 Hz), 3.62e3.55 (2H, m), 3.38 (3H, s),
2.68e2.52 (2H, m), 2.46e2.36 (2H, m), 1.70e1.06 (268H, m), 0.89
(12H, t, J 6.8 Hz), 0.71e0.62 (8H, m), 0.60e0.54 (4H, dt, J 7.6,
4.0 Hz), ꢀ0.32 (4H, br. q, J 5.2 Hz); dC (101 MHz, CDCl3): 175.1, 174.9,
137.6, 137.51, 137.5, 137.4, 137.2, 128.5, 128.4, 128.38, 128.37, 128.0,
127.9, 127.8, 127.71, 127.7, 107.0, 106.3, 105.5, 88.2, 87.9, 87.8, 83.6,
80.6, 80.4, 79.3, 79.1, 72.3, 72.2, 72.0, 71.9, 71.7, 65.6, 63.0, 54.8,
51.85, 51.7, 35.4, 35.2, 31.9, 30.2, 29.8, 29.75, 29.7, 29.6, 29.5, 29.4,
29.2, 28.7, 27.5, 27.4, 25.7, 22.7, 18.5, 18.3, 15.7, 14.1, 10.9; nmax: 3584,
oil (23.1 mg, 97%) [Found (MALDI) (M
þ
Na)þ: 2689.4,
þ40 (c 0.1, CHCl3) which
C
172H328NaO17, requires: 2689.4], ½a D20
ꢂ
showed dH (400 MHz, CDCl3þ few drops CD3OD): 4.94 (1H, d, J
1.3 Hz), 4.92 (1H, br. s), 4.73 (1H, br. s), 4.35 (1H, dd, J 11.8, 4.7 Hz),
4.29 (1H, dd, J 11.5, 3.9 Hz), 4.20 (1H, dd, J 11.5, 4.8 Hz), 4.13 (1H, dd,
J 11.7, 4.8 Hz), 4.09e4.02 (2H, m), 4.02e3.92 (5H, m), 3.89e3.77 (3H,
m), 3.61e3.49 (3H, m), 3.28 (3H, s), 2.38e2.29 (2H, m), 1.51e0.94
(274H, m), 0.79 (12H, t, J 6.8 Hz), 0.61e0.52 (8H, m), 0.47 (4H, dt, J
7.6, 4.0 Hz), ꢀ0.42 (4H, br. q, J 5.1 Hz); dC (101 MHz, CDCl3 þ few
drops CD3OD): 175.1, 175.0, 109.0, 107.9, 107.3, 82.9, 82.2, 81.8, 81.6,
81.0, 80.9, 79.7, 77.8, 77.5, 72.3, 66.0, 63.4, 63.1, 54.7, 52.7, 49.6, 34.7,
31.7, 30.0, 29.9, 29.6, 29.5, 29.4, 29.2, 29.1, 29.0, 28.5, 27.2, 22.4, 15.5,
3064, 3032, 2918, 2850, 1733, 1455, 1018, 732 cmꢀ1
.
(b) Palladium (II) hydroxide on activated charcoal (20% Pd(OH)2-
C, 6.6 mg, 0.30 fold by weight) was added to a stirred solution of
compound 11d (0.030 g, 0.009 mmol) in dry CH2Cl2: MeOH (1:1,
2 mL) at r. t. under hydrogen. After16 h, work up and purification as
before gave the title compound 12d as a colourless oil (17 mg, 64%)
13.8, 10.7, 10.6; nmax: 3400, 2918, 2850, 1735, 1467, 1008 cmꢀ1
.
3.6. Methyl5-O-{2-((1R)-1-hydroxy-16-[(1R,2S)-2-(20-methyl-19-
oxo-octatriacontyl)cyclopropyl]hexadecyl)hexa-cosanoyl}- -D-
a
[Found (M
þ
Na)þ: 2689.4696, C172H328NaO17, requires:
þ36 (c 0.1, CHCl3) which showed dH (400 MHz,
arabinofuranosyl-(1 / 3)-[2,3-di-O-benzyl-5-O-{2-(1R)-1-
hydroxy-16-[(1R,2S)-2-(20-methyl-19-oxoocta-triacontyl)
2689.4694], ½a 1D6
ꢂ
CDCl3 þ few drops CD3OD): 5.03 (1H, d, J 1.5 Hz), 4.99 (1H, br. s),
4.81 (1H, br. s), 4.48 (1H, dd, J 11.9, 4.3 Hz), 4.39 (1H, dd, J 11.7,
4.7 Hz), 4.28 (1H, dd, J 11.5, 4.8 Hz), 4.17 (1H, dd, J 11.4, 4.3 Hz),
4.13e3.09 (2H, m), 4.06e3.98 (5H, m), 3.97e3.86 (3H, m),
3.69e3.58 (3H, m), 3.36 (3H, s), 2.51e2.42 (2H, m), 2.42e2.35 (2H,
m), 1.70e1.00 (271H, m), 0.86 (12H, t, J 6.8 Hz), 0.67e0.58 (8H, m),
0.57e0.50 (4H, dt, J 7.6, 4.0 Hz), ꢀ0.36 (4H, br. q, J 5.1 Hz); dC
(101 MHz, CDCl3 þ few drops CD3OD): 175.2, 175.0, 109.0, 107.8,
107.3, 83.1, 82.9, 81.5, 81.1, 80.0, 77.97, 72.99, 72.9, 65.7, 63.6, 63.2,
54.9, 52.8, 52.7, 31.9, 30.3, 30.2, 29.8, 29.75, 29.7, 29.6, 29.5, 29.4,
28.7, 27.4, 22.7, 15.8, 14.1, 10.9; nmax: v. br. 3400, 2919, 2851, 1732,
cyclopropyl]hexadecyl)hexacosanoyl}-a-D-arabinofuranosyl-
(1 / 5)]- -D-Araf 12f
a
(a) Cesium hydrogencarbonate (0.081 g, 0.417 mmol) was added
to a stirred solution of 10b (0.050 g, 0.042 mmol) and (2R)-2-{(1R)-
1-hydroxy-16-[(2S)-2-[20-methyl-19-oxo-octa-triacontyl]cyclo-
propyl]hexadecyl}hexacosanoic acid [29] (0.114 g, 0.092 mmol) in
dry DMF: THF (1:5, 6 mL) at r. t. under nitrogen. The mixture was
stirred at 70 ꢁC for 4 days, then work up and purification as before
gave compound 11f as a colourless thick oil (0.05 g, 36%) [Found
(MALDI) (M þ Na)þ: 3339.7, C219H382NaO19, requires: 3339.8],
1467, 1099, 760 cmꢀ1
.
½
a 2D3
ꢂ
þ62 (c 0.1, CHCl3) which showed dH (400 MHz, CDCl3):
7.34e7.25 (25H, m), 5.18 (1H, br. s), 5.13 (1H, br. s), 4.91 (1H, br. s),
4.60e4.40 (9H, m), 4.34 (1 H, d, J 11.8 Hz), 4.32e4.24 (4H, m), 4.18
(1H, dt, J 10.7, 3.5 Hz), 4.11 (1H, dd, J 4.1, 2.9 Hz), 4.08 (1H, br. d, J
3.0 Hz), 4.04e4.01 (1H, m), 4.00 (1H, br. d, J 2.4 Hz), 3.96e3.94 (2H,
m), 3.93 (1H, dd, J 7.4, 4.4 Hz), 3.88e3.80 (2H, m), 3.76 (1H, dd, J
12.0, 2.0 Hz), 3.70e3.55 (3H, m), 3.37 (3H, s), 2.67 (1H, br. s),
2.55e2.34 (8H, m), 1.69e1.10 (288H, m), 1.06 (6H, d, J 6.9 Hz), 0.89
(12H, t, J 6.8), 0.66e0.62 (4H, m), 0.61e0.51 (2H, dt, J 7.6,
4.0 Hz), ꢀ0.32 (2H, br. q, J 5.1 Hz); dC (101 MHz, CDCl3): 215.2, 175.1,
174.96, 137.7, 137.5, 137.4, 137.2, 128.4, 128.41, 128.38, 128.36, 128.0,
127.9, 127.8, 127.73, 127.7, 107.0, 106.3, 105.5, 88.2, 87.9, 87.85, 83.7,
80.6, 80.4, 79.3, 79.1, 72.3, 72.2, 72.1, 71.97, 71.8, 68.9, 65.6, 63.0,
54.8, 51.8, 51.7, 50.9, 46.3, 41.1, 33.0, 32.1, 31.9, 30.2, 29.7, 29.66, 29.6,
29.5, 29.49, 29.4, 29.36, 29.3, 29.2, 28.7, 27.4, 27.3, 25.7, 23.7, 22.8,
22.7, 16.4, 15.7, 14.1, 10.9; nmax: 3522, 3066, 2919, 2851, 1735, 1712,
3.5. Methyl-5-O-(2-{(R)-1-hydroxy-12-[(1S,2R)-2-(14-[(1S, 2R)-2-
eicosylcyclopropyl]tetradecyl)cyclopropyl]dodecyl}-
hexacosanoate)-
hydroxy-12-[(1S,2R)-2-(14-[(1S,2R)-2-eicosylcyclopropyl]
tetradecyl)-cyclopropyl]dodecyl}hexacosanoate)- -D-
arabinofuranosyl-(1 / 5)]- -D-Araf 12e
a-D-arabinofuranosyl-(1 / 3)-[5-O-(2-{(R)-1-
a
a
1. (a) Cesium hydrogencarbonate (0.081 g, 0.417 mmol) was
added to a stirred solution 10b (0.050 g, 0.042 mmol) and 2-{(R)-1-
hydroxy-12-[(1S,2R)-2-(14-[(1S,2R)-2-eicosylcyclo-propyl]tetra-
decyl)cyclopropyl]dodecyl}hexacosanoic acid [27] (0.105 g,
0.092 mmol) in dry DMF: THF (1:5, 3 mL) at r. t. under hydrogen.
The mixture was stirred at 70 ꢁC for 4 days, then work and purifi-
cation as before gave a colourless oil, compound 11e (31 mg, 11%)
[Found (MALDI) (M þ Na)þ: 3139.7, C207H358NaO17 requires:
1467, 1111, 756, 720 cmꢀ1
.
3139.7], ½a 2D3
ꢂ
þ80 (c 0.1, CHCl3) which showed dH (400 MHz, CDCl3):
3. (b) Palladium (II) hydroxide on activated charcoal (20%
Pd(OH)2-C, 13.8 mg, 0.30 fold by weight) was added to a stirred
solution of compound 11f (0.046 g, 0.013 mmol) in dry CH2Cl2:
MeOH (1:1, 2 mL) at r. t. under hydrogen. After 16 h, work up and
chromatography as before gave the title compound 12f as a col-
7.35e7.27 (25H, m), 5.18 (1H, br. s), 5.13 (1H, br. s), 4.91 (1H, br. s),
4.61e4.39 (9H, m), 4.40 (1H, d, J 12.8 Hz), 4.35 (1H, dd, J 9.4, 4.6 Hz),
4.32e4.23 (5H, m), 4.21e4.17 (1H, m), 4.11e4.05 (2H, m), 4.00 (1H,
br. d, J 2.7 Hz), 3.98e3.95 (1H, m), 3.95e3.91 (1H, m), 3.90e3.85
(2H, m), 3.76 (1H, dd, J 11.7, 2.2 Hz), 3.66e3.57 (2H, m), 3.37 (3H, s),
2.69e2.62 (2H, m), 2.45e2.36 (2H, m), 1.64e1.07 (268H, m), 0.89
ourless oil (26 mg, 65%) [Found (M
þ
Na)þ: 2889.6404,
C
184H352NaO19, requires: 2889.6470], ½a D23
þ33 (c 0.1, CHCl3) which
ꢂ
(12H, t,
J
6.9 Hz), 0.70e0.61 (8H, m), 0.56 (4H, dt,
J
7.6,
showed dH (400 MHz, CDCl3þ few drops CD3OD): 5.00 (1H, d, J
4.0 Hz), ꢀ0.33 (4H, br. q, J 5.2 Hz); dC (101 MHz, CDCl3): 175.1, 175.0,
1.8 Hz), 4.96 (1H, d, J 0.6 Hz), 4.79 (1H, br. s), 4.43 (1H, dd, J 12.2,

42
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(1H, dd, J 11.4, 4.2 Hz), 4.13e4.07 (2H, m), 4.04e3.97 (5H, m),
3.94e3.84 (3H, m), 3.67e3.56 (4H, m), 3.34 (3H, s), 3.11 (1H, d, J
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Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.carres.2016.11.006.
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