Synthesis of new chiral macrocycles-based glycolipids and its application in asymmetric Michael addition

Article abstract of DOI:10.1007/s11164-021-04432-8

A series of new mix aza- and thia-macrocyclic glycolipids (9, 10, 16 and 17) have been synthesized and their enantiomeric selectivity was studied. The synthesis of the macrocycles involved a simple protection of two hydroxyl groups of the glycolipids followed by building up the mix-heteroatom macrocyclic in simple sequences. The macrocycles and previously investigated analogues (18, 19, 20 and 21) have been applied as phase transfer catalysts in the enantioselective Michael addition of 2-nitropropane to chalcone and showed good-to-excellent enantiomer excess (ee). Among the catalysts, the galactose aza-crown ether-based glycolipid 21 proved to be the most effective with 90% ee. Graphic abstract: [Figure not available: see fulltext.]

Full text of DOI:10.1007/s11164-021-04432-8

Research on Chemical Intermediates
https://doi.org/10.1007/s11164-021-04432-8
Synthesis of new chiral macrocycles‑based glycolipids
and its application in asymmetric Michael addition
Karem J. Sabah1 · N. Idayu Zahid · Rauzah Hashim
2
2
Received: 15 October 2020 / Accepted: 4 March 2021
©
The Author(s), under exclusive licence to Springer Nature B.V. 2021
Abstract
A series of new mix aza- and thia-macrocyclic glycolipids (9, 10, 16 and 17) have
been synthesized and their enantiomeric selectivity was studied. The synthesis of the
macrocycles involved a simple protection of two hydroxyl groups of the glycolip-
ids followed by building up the mix-heteroatom macrocyclic in simple sequences.
The macrocycles and previously investigated analogues (18, 19, 20 and 21) have
been applied as phase transfer catalysts in the enantioselective Michael addition of
2
-nitropropane to chalcone and showed good-to-excellent enantiomer excess (ee).
Among the catalysts, the galactose aza-crown ether-based glycolipid 21 proved to be
the most eꢀective with 90% ee.
*
Karem J. Sabah
karemchemist@gmail.com; kareemj.alabidi@uokufa.com
1
2
Department of Chemistry, Faculty of Science, University of Kufa, Najaf 54001, Iraq
Centre for Fundamental and Frontier Sciences in Nanostructure Self-Assembly, Department
of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
Vol.:(012
1
3456789)
3

K. J. Sabah et al.
Graphic abstract
Keywords Glycolipids · Macrocycles · Asymmetric · Michael addition · Aza ·
Templating
Introduction
The chiral crown ethers are of interest in various chemical applications, mainly in
asymmetric organic reactions [1–4]. The carbohydrate-based crown ether moieties
represent an important group of optically active compounds [5, 6]. By containing
more than one stereogenic centers as active sites, they can serve as one of the good
candidates for chiral recognition [7, 8], asymmetric reactions [9–12], and enanti-
omers puriꢁcations [13–15]. Among carbohydrate-containing macrocycles, the gly-
colipid involving crown ethers on their constructions representing a new class of
lariat chiral crown ethers [16]. From the synthetic aspects, the balance between lipo-
philicity and hydrophobicity of compound is a crucial factor for micelle formation
to act as a phase transfer catalyst [17]. The typical bond formation processes involve
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
in phase transfer catalyst reaction are asymmetric Michael addition and epoxidation
reactions [18–22]. In general, the reaction provides a practical access to a variety
of optically active materials, which are useful in the ꢁeld of medicinal [23], phar-
maceutical [24], and agrochemical [25]. In this context, the synthesis of new chi-
ral mix-heteroatoms crown ethers with suitable lariat side arm could be a promis-
ing material as phase transfer catalyst in obtaining enantiomer excess (ee) product
[
26–28].
The demands of obtaining stereoselective reactions in the formation of car-
bon–carbon single bond by the addition of enolates or their analogous to the α–β
unsaturated carbonyl compounds have been extensively investigated [29]. Due to
its signiꢁcant relevance in preparing biologically active materials, many research-
ers focus on carrying out the Michael addition of carbon nucleophiles to conjugated
enones using stereoselective approach. A few sugar-based crown ethers which con-
tains carbohydrate moieties as the source of chirality have been successfully used as
catalysts in asymmetric Michael addition reactions [9, 30]. Bako et al. reported that
the yield and the enantioselectivity of the 1,2-addition reaction of 2-nitropropane
to chalcone catalyzed by glucose-based chiral lariat ethers and crown ether derived
from D-mannitol was greatly inꢂuence by the substituents on the nitrogen atom of
the macrocycle [30].
Recently, our attention was drawn to macrocyclic compounds containing the sin-
gle chain lauryl glucoside units [31] and the mixed heteroatom thiadiaza and triaza
crown ether attached to lauryl galactoside and glucoside [32]. We also previously
published on the new sugar-thiacrown-ether appended calix[4]arene, coupled with
pyrene units macrocycles and demonstrated the common approaches to the synthesis
of these macrocycles [33, 34]. In continuation of our ongoing program to develop
innovative procedures to synthesize novel macrocycles, we report here the synthe-
sis of new mix-heteroatoms macrocycles design including those with double chain
glycoside units. Also, we anticipated to evaluate how the diꢀerent position of mac-
rocycles, type of heteroatoms on macrocyclic part, lariat side chain on the anomeric
center, alkyl chain type and sugar head inꢂuence the stereoselectivity in the reaction
of chalcone and 2-nitropropane.
Results and discussion
Synthesis
The glycolipid 4 (Scheme 1) was synthesized according to the standard procedure
we reported previously [32]. The glucose was treated with acetic anhydride under
basic condition to obtain β-glucose pentaacetate, and then reacted with the branched
chain alcohol, i.e., 2–butyl–1–octanol under acidic boron triꢂuoride to obtain a fully
acetylated glycolipid 3 with major β–anomer. We carried out the column chroma-
tography in the next reaction sequence as it is more cost-eꢀective and time-saving
way to remove the trace of α-anomer. The deacetylation of protected glycolipids 3
to obtain free hydroxyl groups on the sugar head is necessary to functionalize the
material and building the desired macrocycles. Sodium methoxide in methanol has
1
3

K. J. Sabah et al.
Scheme 1 Synthesis of aza and thia macrocycles 9 and 10 on 2,3-positions
been used as an agent to achieve the clean deprotected glycolipid 4 as a mixture of
α–/β–anomers. Furthermore, the functionalization of glycolipid 4 with benzylidene
protecting group enables not only for gaining free diol 5 at 2- and 3-positions, but
also to get pure β-anomer after simple crystallization. This was achieved by the reac-
tion of 4 with benzaldehyde dimethyl acetal in the presence of catalytic amount of
TsOH in DCM. The diol 5 was introduced with ethylamine arm in two steps, by
the treatment of 5 with bromoacetonitrile under phase transfer catalyst in a mixture
of toluene and aqueous sodium hydroxide 50%, followed by the reduction of 6 by
LiAlH in dry cyclic ether to get the diamine 7. The diamine 7 was formed by addi-
4
tion of 2.2 equivalents chloroacetic anhydride in DCM in the presence of triethyl-
amine as base. This procedure allows us to get a pure dichloro precursor 8 which
serve as macrocyclic backbones without chromatographic puriꢁcation. The macro-
cycle 9 was obtained by the treatment of 8 with Na S·9H O in a mixture of ethanol:
2
2
water 85:15 ratio in relatively high yield 79%. In the same manner, the benzyl amine
was used to form macrocycle 10 by adding it with dichloro derivative 8 in acetoni-
trile in the presence of sodium carbonate in 59% yield after chromatography.
This extraordinary yield obtained by this approach could be justiꢁed in terms of
templating eꢀect. Initially, the sulꢁde attacks the nucleophilic carbon which pos-
sessing the chloride by S 2 reaction, the free sodium will act as a templating agent
N
to assist the pre-organization of ring formation which allow the other nucleophilic
carbon to be in a suitable position to form the macrocycle (Scheme 2).
On the other hand, the macrocycles on 4- and 6-positions of the glucopyra-
noside ring could be obtained by manipulating the protecting strategy to aꢀord
1
2 (Scheme 3) [31]. The acid catalytic cleavage of benzylidene group of lauryl
2
,3–O–dibenzyl–4,6–benzylidene glucopyranoside furnished 12. Intermediate 12
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
Scheme 2 Sodium templating-assisted macrocyclization
Scheme 3 Synthesis of thia- and aza-macrocycles 16 and 17 on 4,6-positions
was treated with the same sequence of reactions including alkylation with bromoace-
tonitrile under phase transfer catalyst condition to produce 13 in good purity with an
excellent yield (84%). Subsequently, the diamino 14 was obtained by treatment of 13
with LiAlH in dry THF. The acylation of 14 with chloroacetic anhydride gave the
4
dichloroamido derivative 15 in almost 90% yield. Finally, the cyclization reactions
of intermediate 15 with either Na S·9H O or BnNH aꢀorded the macrocycles 16
2
2
2
(
77% yield) and 17 (61% yield), respectively. When compared, the yield of macrocy-
cles 4-,6-positions is relatively lower than 2,3-positions analogues.
Michael addition of 2–nitropropane to chalcone
The addition of 2–nitropropane to chalcone was investigated under phase transfer
catalytic conditions in the presence of macrocycles 9, 10, 16 and 17. We also include
macrocycles 18, 19, 20 and 21 (Fig. 1) in which their synthetic procedures have
been described in our previous work [32, 33]. Besides, their non-sugar analogues 22
and 23 were also assessed (Fig. 1).
The phase transfer catalytic reaction in solid–liquid phase was carried out at
room temperature using dry toluene, 30% of solid sodium tert-butoxide and 5%
1
3

K. J. Sabah et al.
Ph
O
O
O
O
Ph
O
O
O
O
OC12H
25
O
OC12
H
25
O
O
O
NH
NH
NH
HN
HN
HN
O
Y
O
Y
Y
O
O
O
O
2
2
3
Y = S
1
8
Y = S
2
0
Y = S
Y =NHCH Ph
2
2
Y =NHCH Ph
1
9
Y =NHCH Ph
2
2
1
2
Fig. 1 Macrocycles 18–21 incorporating glucose-based and galactose-based glycolipids, while macrocy-
cles 22 and 23 representing its non-sugar analogs
of the chiral catalysts (Scheme 4). The preparative TLC was used for obtain-
1
ing the product and the enantiomeric excess (ee %) was determined by H NMR
spectroscopy in the presence of Eu(hfc) as a chiral shift reagent. The signiꢁcant
3
results of asymmetric Michael addition are listed in Table 1. A few factors were
addressed here to study the eꢀects of sugar head group, position of macrocycles,
O
O
H
H
3
C
(i)
+
NO
2
*
H
3
C
H
3
C
CH
3
2
NO
Scheme 4 Michael addition of 2-nitropropane to chalcone. Reagents and conditions: (i) catalyst (9,10)
and one of (16–23), sodium tert-butoxide and toluene
Table 1 Asymmetric Michael
Yield (%)a
ee (%)b
Entry
Catalyst
Time (h)
addition of 2-nitropropane to
chalcone catalyzed by mix-
heteroatoms macrocycles
1
2
3
4
5
6
7
8
9
9
2
2
4
4
2
2
2
2
2
2
71
75
66
70
75
71
67
74
79
82
67 (S)
72 (S)
58 (S)
61(S)
72 (S)
78 (S)
80 (S)
90 (S)
0
10
16
17
18
19
20
21
22
23
1
0
4(R)
a
Based on products isolated by preparative TLC
Determined by H NMR spectroscopy
b
1
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
type of heteroatoms on macrocyclic part, the lariat side chain on the anomeric
center and the straight vs. branched alkyl chain on the asymmetric addition.
The highest enantiomeric excess (ee) was obtained using catalyst 21, the galac-
tose-based with benzylamino-residue on the macroring at 2,3-positions, followed
by its thia-analogue 20 with ee of 90 and 80%, respectively (entries 7 and 8). This
result can be explained by the fact that the benzyl groups on the nitrogen atom of
2
1 which oriented in a way to block one side of the macrocycle enforce the addition
to be mainly from the opposite side compared to that of thia-analogue 20. Moreo-
ver, the benzylidene group on galactose derivatives 20 and 21 at 4-position is axial
which make the steric eꢀect in one side is greater than the equatorial orientation at
4
-position of glucose analogues 18 and 19. Furthermore, the lipophilic alkyl chain,
i.e., straight and branched hydrocarbon tails on compounds 9, 10, 18 and 19 (entries
, 2, 5 and 6) were found to be less eꢀective in ee with the values of 67–78%. The
1
stereoselectivity of macrocyclic sugar on 4,6-positions 16 and 17 (entries 3 and 4)
were 58 and 61% ee, respectively which is less than the 2,3-anologues. This could
be explained by the less stereocenters available and less rigidity in the macrocyclic
structure of 16 and 17 compared to that of 18 and 19 analogues. Unsurprisingly, the
non-sugar macrocyclic analogues 22 and 23 (entries 9 and 10) showed no enantio-
meric excess at all. This outcome is expected due to the non-chirality in their struc-
tures in contrast to their sugar analogues.
Conclusion
The new mix-heteroatoms crown ethers glycolipids involving 2,3-positions on glu-
cose with branched tail 9 and 10 and its analogues on 4,6-positions with straight
chain 16 and 17 were synthesized successfully in good yields. Their stereoselective
toward asymmetric Michael addition of 2-nitropropane to chalcone are investigated
beside their galactose (20, 21) and glucose (18, 19) straight chain analog. Among
the studied catalysts, the galactose aza-crown ether-based glycolipid 21 exhibits the
highest enantiomeric excess (ee) by 90%.
Experimental
General methods
All reagents were obtained from commercial sources and used without further puri-
ꢁ
cation. Flash column chromatography was carried out on silica gel 60 (230–400
mesh, E. Merck). TLC was performed on pre-coated aluminum plates of Silica Gel
6
0 F (0.25 mm, E. Merck. NMR spectra were recorded on Bruker Avance and
254
1
13
Joel ECA spectrometers at 400 MHz for H and 100 MHz for C, respectively.
Chemical shifts were in ppm from Me Si, calibrated using the residual proton and
4
carbon of the deuterated solvent. Proton peak assignments were performed with the
1
1
aid of 2D NMR techniques ( H- H COSY and HSQC/HMQC) the hydrogen multi-
plicities of carbon peaks were determined using DEPT and PENDANT experiments.
1
3

K. J. Sabah et al.
High-resolution mass spectra were recorded on an Agilent Technologies 6530 Accu-
rate Q-TOF LC–MS system, applying MeOH–water eluents. A gas ꢂow of 250 °C
hot nitrogen at 5 mL, min and electrospray ionization at 125 eV were applied.
General procedure for cyanomethylation
The glycolipid 5 or 12 (2 mmol) was dissolved in a mixture of toluene (30 mL),
5
0% NaOH solution (20 mL) and tetrabutyl ammonium hydrogen sulfate (1 mmol)
and stirred at 10 °C for 30 min. Bromoacetonitrile (4 mmol) was added dropwise.
The mixture was stirred for 2 h. Hexane (50 mL) was added and the organic layer
was separated, ꢁltered through pad of celite, dried over MgSO and the solvent
4
was evaporated. The crude material could be crystallized or puriꢁed by column
chromatography.
General procedure of reduction of aminoethyl derivatives
Compound 6 or 13 (1 mmol) was dissolved in THF (50 mL) and was cooled to 0 °C.
LiAlH (4 mmol) was added in small portion carefully within 30 min. The mixture
4
was stirred for 1 h. The complete conversion of the reaction was indicated by TLC.
Ethyl acetate (10 mL) was added and stirring was continued for 15 min to destroy
excess LiAlH . The solid was ꢁltered, and the solvent was evaporated to give the
4
crude amine, which was pure enough to be used without further puriꢁcation.
General procedure of amide formation
Compound 7 or 14 (2 mmol) was dissolved in DCM (100 mL) and was cooled to
0
°C. (ClCH CO) O (4.4 mmol) was added in small portion. The mixture was stirred
2 2
for 2 h at 0 °C and then leave at room temperature overnight. TLC indicated the
complete consumption of the starting materials. The mixture was washed with satu-
rated NaHCO solution followed by water. The organic layer was dried over MgSO
3
4
and the solvent was evaporated to give the reasonable pure diamide which was either
used directly or puriꢁed by ꢂash chromatography.
General procedure of thiadiamido crown ether formation
Compound 8 or 15 (1 mmol) was dissolved in EtOH (120 ml) and the reaction was
stirred at room temperature for 15 min. Na S·9H O (1 mmol) was added and the
2
2
mixture was heated at reꢂux for 1 h followed by Na S·9H O (0.5 mmol) and was
2
2
continued to reꢂux for additional 3 h. The EtOH was evaporated when the TLC
showed there were no starting materials left. The residue was dissolved in DCM
(
50 mL), washed with water and dried over MgSO . The solvent was evaporated,
4
and ꢂash chromatography was applied to obtain the pure crown ether.
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
General procedure of benzylaza‑diamido crown ether formation
Compound 8 or 15 (1.0 mmol) was dissolved in acetonitrile (100 ml) and then
Na CO (10 mmol) was added. Benzyl amine (1.2 mmol) was added and the
2
3
mixture was heated heated at reꢂux for 12 h. When TLC showed there was no
starting materials remained, the mixture was cooled down to room temperature,
ꢁ
ltered and the solvent was evaporated under reduced pressure. The remaining
was dissolved in DCM (50 mL) and washed with water, dried over MgSO . The
4
solvent was evaporated, and ꢂash chromatography was applied to get the pure
macrocycle.
General procedure of Michael addition of 2‑nitropropane to chalcone
The series of macrocycles 9, 10, 16, 17, 18, 19, 20, 21, 22 and 23 were subjected to
Michael addition reaction of 2–nitropropane to chalcone. The preparative TLC was
1
used for isolating the product after normal workup sequence. The H NMR spectros-
copy was employed to determine the enantiomeric excess (ee %) using Eu(hfc) as a
3
chiral shift reagent.
2
‑butyloctyl 4,6–O–benzylidene–β–D–glucopyranoside 5
Crude 4 (7.2 g, 20 mmol) and benzaldehyde dimethyl acetal (7.4 mL, 48 mmol)
were dissolved in 150 mL DCM. P–TsOH (100 mg) was added according to gen-
eral benzylidenation procedure, to give pure β-anomer 5 (4.6 g, 53%). [α] =–38
D
1
(
(
c=0.21, CHCl ). H NMR (400 MHz, CDCl ) δ=7.51–7.24 (m, 5 H; Ph), 5.52
3
3
s; Ph-CH), 4.34–4.28 (m, 2 H; H-1, H-6 eq), 3.82–3.78 (m, 3 H; H-2, H-3,H-6ax),
3
3
.56–3.35 (m, 4 H; H-4, H-5,α-CH ), 3.15 (d, 1 H, J=8.0 Hz; OH-3), 2.76 (d, 1
2
3
H, J=8.0 Hz; OH-2),1.62–1.60 (m, 1 H; β-CH), 1.31–1.25 (m, 16 H; bulk-CH ),
2
0
.92–0.86 (m, 6 H; 2CH ).
3
1
3
C NMR (100 MHz, CDCl ) δ=137.04 (Ph-C), 129.24/128.33/126.32 (Ph-CH),
3
1
03.48 (C-1), 101.89 (PhCH), 80.64 (C-4), 74.68 (C-2), 73.66 (C-3), 73.64 (α-CH ),
2
(
73.08 CH), 68.70 (C-6), 66.39 (C-5), 38.19 (β), 31.88/31.86/31.21/31.15/30.88/30.
8
2/29.69/28.96/28.94/26.73/26.68/23.05/ 22.67 (bulk-CH ), 14.12 (2 CH ).
2
3
2
‑butyloctyl 4,6–O–benzylidene–2,3–bis–O–[cyanomethyl]–β–D–
glucopyranoside 6
Compound 5 (2.7 g, 6.2 mmol) in toluene (40 mL) was treated with aqueous NaOH
(
25 mL, 50%), Bu N.HSO (1.4 g, 4 mmol) and BrCH CN (3.80 g, 32 mmol) accord-
4
4
2
ing to general procedure 4.1.2 to give 6 as a white solid (2.61 g, 82%). [α] =–29.0
D
1
(
c=1.2, CH Cl ). H NMR (400 MHz, CDCl ) δ=7.52–7.35 (m, 5 H; Ph), 5.57 (s,
2
2
3
3
1
H; Ph-CH), 4.56–4.54 (mc, 4 H; CH CN), 4.45 (d, 1 H, J =7.5 Hz; H-1), 4.37
2 1,2
2
3
(
dd, 1 H,, J
=10.8, 5.0 Hz; H-6 eq), 3.82 (dt, 2 H,, J=8.0, 5.5 Hz; α-CH ,
eq,6ax 2a
6
1
3

K. J. Sabah et al.
α- CH ), 3.75–3.65 (m, 2 H; H-6ax, H-4), 3.47–3.35 (m, 3 H; H-3,H-5,H-2),1.63
2
b
(
mc, 1 H; β-CH), 1.39–1.24 (m, 16 H; bulk-CH ), 0.95–0.88 (m, 6 H; 2 CH ).
2
3
13
C NMR (100 MHz, CDCl ) δ=136.68 (Ph-C), 129.31 / 128.37/ 126.08 (Ph-
3
CH), 116.15/ 115.83 (2 C≡N), 103.00 (C-1), 101.52 (Ph-CH), 81.91 (C-2), 80.85 /
8
0.65 (C-3, C-4), 73.45 (α-CH ), 73.38 (CH), 68.55 (C-6), 65.71 (C-5), 57.72/ 57.63
2
(
2 CH C≡N), 38.16 (β), 31.86/ 31.23/ 31.18/30.90/ 30.88/ 29.66/ 28.96 / 28.89
2
/
26.73/26.68 / 23.06/ 22.67 (bulk-CH ), 14.10 (2 CH ).
2 3
+
HRMS: [M+Na] calcd. for C H N O Na: 537.2941; found: 537.2934.
2
9
42
2
6
2
7
–butyloctyl 4,6–O–benzylidene–2,3–bis–(2–aminoethyl)–β–D–glucopyranoside
Cynomethylated glycolipid 6 (2.0 g, 3.9 mmol) was subjected to general reduction
procedure 4.1.2 to give amino-glycolipid 7 as a pale-yellow semisolid (1.78 g, 88%).
[
α] =–50.0 (c=1.3, CH Cl ). The product was subjected to the next reaction with-
D 2 2
out puriꢁcation.
2
‑butyloctyl 4,6–O–benzylidene–2,3–bis–[2–(2–chloroacetamido)ethyl]–β–D–
glucopyranoside 8
Compound 7 (2.08 g, 4.0 mmol) and (ClCH CO) O (1.52 g, 8.8 mmol) were
2
2
subjected to general procedure 4.1.3 to give diamide 8 as a pale-yellow semi-
1
solid (2.28 g, 85%). [α] = +3.7 (c=0.2, CHCl ). H NMR (400 MHz, CDCl )
D
3
3
3
δ=7.39–7.27 (m, 5 H; Ph), 6.82 (t, 1 H, J=5.5 Hz; CONH), 6.71 (t, 1 H,
3
3
J=5.5 Hz; CONH), 5.46 (s; Ph-CH), 4.32 (d, 1H, J =7.8 Hz; H-1), 4.28 (dd,
1
,2
2
1
H, J
=10.5, 5.0 Hz; H-6 eq), 4.02–3.98 (m, 1 H; CH O), 3.94–3.75 (m, 1
6
eq,6ax 2a
H; CH O), 3.78–3.66 (m, 4 H; α-CH , 2 CH Cl, H-6ax), 3.65–3.48 (m, 4 H; H-3,
2
a
2a
2a
H-4, α-CH ), 3.35–3.24 (m, 4 H; H-2, 2 CH Cl, CH, CH N), 3.23–3.11 (m, 5 H;
2
b
2b
2
H-5, CH N), 1.54–1.46 (mc, 1 H; β-CH), 1.30–1.15 (m, 16 H; bulk-CH ), 0.92–0.88
2
2
(
m, 6 H; 2 CH ).
3
1
3
C NMR (100 MHz, CDCl ) δ=167.88, 167.81 (C=O), 137.1 (Ph-C), 129.14 /
3
1
28.34/ 125.87 (Ph-CH), 104.02 (C-1), 101.19 (Ph-CH), 82.07 (C-2), 80.31/ 79.53
(
C-3, C-4), 73.24/ 73.18 (2 CH O), 71.34/ 71.07 ( 2 α-CH ), 68.69 (C-6), 65.81
2
2
(
C-5), 39.72/ 39.58 (2 CH Cl), 38.22 (β), 36.49/ 36.46 (2 CH N)/ 31.29/31.14/
2
2
3
0.96/ 30.85/ 29.66/ 29.63/ 29.05/ 28.86 /26.80/26.63 / 23.04/ 23.00/ 22.63 (bulk-
CH ), 14.07 (2 CH ).
2
3
+
HRMS: [M+Na] calcd. for C H Cl N O Na: 697.2998; found: 697.2989.
3
3
52
2
2
8
2
‑butyloctyl 4,6–O–benzylidene–2,3–[15–cr–5]thiadiamido–β–D–
glucopyranoside 9
Compound 8 (0.47 g, 0.7 mmol) and Na S.9H O (0.25 g, 1.06 mmol) were subjected
2
2
to general procedure 4.1.4 to give 9 as a white semisolid (0.35 g, 79%). [α] =–35.0
D
1
(
c=0.2, CHCl ). H NMR (400 MHz, CDCl ) δ=7.52–7.34 (m, 5 H; Ph), 7.14 (t, 1
3
3
3
3
H, J=5.5 Hz; CONH), 7.02 (t, 1 H, J=5.5 Hz; CONH), 5.55 (s; Ph-CH), 4.39 (d,
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
3
2
1
H, J =7.8 Hz; H-1), 4.35 (dd, 1 H, J
=10.5, 5.0 Hz; H-6 eq), 4.11–4.07
1
,2
6eq,6ax
(
mc, 1 H; 2 CH N), 4.02–3.87 (mc, 2 H; CH O), 3.85–3.74 (m, 4 H; α-CH
2a 2a 2a,
CH O, H-6ax), 3.70–3.35 (m, 10 H; α-CH , CH N, H-3, H-4, H-5, 2 CH S), 3.35
2
b
2b
2b
2
3
(
dd~t, 1 H, J =9.0 Hz; H-2), 1.64 (mc, 1 H; β-CH ), 1.38–1.24 (m, 16 H; bulk-
2,3 2
CH ), 0.92–0.88 (m, 6 H; 2 CH ).
2
3
1
3
C NMR (100 MHz, CDCl ) δ=166.075, 166.01 (C=O), 136.94 (Ph-C),
3
1
29.36/128.42/ 126.08 (Ph-CH), 103.91 (C-1), 101.69 (Ph-CH), 82.27 (C-2), 81.06
(
C-4), 80.84 (C-3), 73.45/73.39 (α-CH ),71.40/71.34 (2 CH O), 68.73 (C-6), 66.04
2
2
(
C-5), 42.66/42.46 (2 CH NH), 40.19/39.91 (2 CH S), 38.22 (β), 31.86/ 31.23/
2
2
3
1
0.90/30.80/ 29.70/29.67 /28.96/28.90/26.70/(bulk- CH ), 23.07(γ), 22.65 (ω-1),
2
4.11 (2 ω).
+
HRMS: [M+Na] calcd. for C H N O SNa: 659.3342; found: 659.3437.
3
3
52
2
8
2
‑butyloctyl 4,6–O–benzylidene–2,3–[15–cr–5]triazadiamido–β–D–
glucopyranoside 10
Compound 8 (0.42 g, 0.62 mmol), benzyl amine (0.08 g, 0.74 mmol) and Na CO
2
3
(
0.63 g, 6.0 mmol) were subjected to general procedure 4.1.5, to give 10 as a yellow
1
semisolid (0.26 g, 59%). [α] =–44.0 (c=0.2, CHCl ). H NMR (400 MHz, CDCl )
D
3
3
δ=7.39–7.20 (m, 11 H; 2 Ph, CONH), 7.10 (br., 1 H; CONH), 5.50 (s; Ph-CH),
3
2
4
.37 (d, 1H, J =7.8; H-1), 4.30 (dd, 1 H, J
=10.5, 5.0; H-6 eq), 4.16–4.02
1
,2
6eq,6ax
(
m, 2 H, CH O), 3.81–3.70 (m, 2 H; H-6ax, α-CH ), 3.66–3.50 (m, 9 H; H-4, H-3,
2a 2a
2b
α-CH , CH O, NCH PH, CH N), 3.40–3.28 (m, 2 H; α-CH , H-5), 3.24–3.10
2
b
2
2a
2b
(
m, 5 H; H-2, 2 CH NHCO, CH N), 1.52 (mc, 1 H; β-CH), 1.32–1.15 (m, 16 H;
2b 2b
bulk-CH ), 093–0.88 (m, 6 H; 2 CH ).
2
3
13
C NMR (100 MHz, CDCl ) δ=169.63/169.61 (2 C=O), 136.98/136.48 (2
3
Ph-C), 129.16 /129.06/128.94/128.54/128.37/128.15/126.45/125.86 (Ph-CH),
1
04.22 (C-1), 101.11 (Ph-CH), 82.19 (C-4), 80.63 (C-2), 79.94 (C-3), 73.53
(
α-CH ), 71.34 /71.02 (2 CH O), 68.74 (C-6), 65.73 (C-5), 60.34 (PhCH N), 59.21/
2
2
2
5
2
9.00 (2 CH CONH), 39.15/39.05 (2 CH NH), 38.21 (β), 31.87/31.31/ 30.98/ 30.83/
2
2
9.69 / 29.66/29.06/ 28.83/26.62 (bulk- CH ), 23.07(γ), 22.65 (ω-1), 14.20/ 14.11 (2
2
ω).
+
HRMS: [M+Na] calcd. for C H N O Na: 732.4270; found: 732.4290.
4
0
59
3
8
Dodecyl 4,6–O–benzylidene–2,3–di–O–benzyl–β–D–glucopyranoside 11
The glycolipid 4 (4.36 g, 10 mmol) was dissolved in DMF (100 mL) and NaH 60%
suspension in paraꢃn oil (2.4 g, 40 mmol). The mixture was stirred for 1 h and
then was cooled to 0 °C. Benzyl bromide (4.08 g, 24 mmol) was added dropwise,
and the reaction mixture was stirred for 2 h at room temperature. MeOH (30 mL)
was added with stirring followed by water (20 mL) to obtain a white precipitate,
which was ꢁltered, washed with MeOH (5×5 mL) and dried. The compound was
subjected to column chromatography to give 11 as a yellow syrup (5.54 g, 90%).
1
[
α] = +5.4 (c=1.0, CH Cl ). H NMR (400 MHz, CDCl ) δ=7.44–7.22 (m, 15
D
2
2
3
H; Ph), 5.53 (s, 1 H; Ph-CH), 4.84 (d, 2 H; Bn), 4.76–4.66 (2 d, 2 H; Bn), 4.43 (d,
1
3

K. J. Sabah et al.
3
2
1
H, J =8.0 Hz; H-1), 4.28 (dd, 1 H, J
=11.0, 5 Hz; H-6 eq), 3.90–3.82
1
,
,2
H-6 eq,ax
2
(
dt, 1 H J
=8.0, 2.3 Hz; α-CH ), 3.77–3.57 (m, 3 H; H-3, H-4,H-6ax), 3.53-
CH2a,,b
2a
2
3
3
3
.45 (dt, 1 H, J
=8.0, 2.3 Hz; α-CH ), 3.40 (t~dd, 1 H, J =9.0 Hz; H-2),
CH2a,,b
2b
1,2
.40–3.33 (m,2H; H-3, H-5), 1.61–1.53 (m, 2 H; β-CH ), 1.35–1.13 (m, 18 H; bulk
2
3
CH ), 0.86 (t, 3 H, J=8.0 Hz; CH ).
2
3
1
3
C NMR (100 MHz, CDCl ) δ=138.53/138.37/137.34 (Ph-C), 128.93/128.33/1
3
2
8.29/128.24/128.12/128.03/127.71/127.61/126.00 (Ph), 104.16 (C-1), 101.11 (Ph-
CH), 82.15 (C-2), 81.51/ 80.89 (C-3, C-4), 75.35 / 75.13 (Ph-CH ), 70.66 (α-CH ),
2
2
6
8.83 (C-6), 66.00 (C-5), 31.93 (β), 29.78/29.71/29.68/29.64/29.59/28.46/29.37
(
bulk-CH ), 26.13 (γ), 22.70 (ω-1), 14.21 (ω).
2
+
HRMS: [M+Na] calcd. for C H O Na: 639.3662; found: 639.3672.
3
9
52
6
Dodecyl 2,3–di–O–benzyl–β–D–glucopyranoside 12
Compound 11 (5.5 g, 10 mmol) was dissolved in CHCl : MeOH 1:1 (150 mL),
3
and p-toluenesulfonic acid (200 mg) was added. The mixture was stirred for
1
2 h at room temperature. Water (150 mL) was added and the organic phase was
washed with saturated NaHCO solution (2×50 mL). The organic phase was dried
3
over MgSO and the solvent was evaporated. Column chromatography of the res-
4
idue gave 12 as a yellow semisolid (4.38 g, 93%). [α] = +4.0 (c=1.0, CH Cl ).
D
2
2
1
2
H NMR (400 MHz,CDCl ,) δ=7.38–7.29 (m, 10 H; aromatic), 4.90 (2 d, 2 H,
3
2
3
J
=11.0 Hz; Bn) 4.62 (2d, 2 H, J =11.0 Hz; Bn), 4.38 (d, 1 H, J =8.0 Hz;
Bn
Bn 1,2
2
H-1), 3.87 (dt, 1 H,
J
=9.1 Hz; α-CH ), 3.81 (dd, 1 H; H-6 eq), 3.67
α-CH2a,α-CH2b
2a
2
(
dd, 1 H, J
=11.0, 5.0 Hz; H-6ax), 3.51–3.44 (m, 2 H; H-4, α-CH ) 3.38
H-6 eq, ax
2b
3
3
(
t~dd, 1 H, J =9.0 Hz; H-2), 3.33 (t~dd, 1 H, J =9.0 Hz; H-3), 3.28- 3.23 (m,
2
,3
2,3
1
H; H-5), 1.66–1.55 (m, 2 H; β-CH ), 1.37–1.12 (m, 18 H; bulk CH ); 0.88 (t, 3 H,
2
2
3
J=8.0 Hz; CH ).
3
1
3
C NMR (100 MHz, CDCl ) δ=138.50/138.32 (Ph-C), 128.64, 128.41, 128.13,
3
1
7
2
27.96, 127.76 (Ph), 103.85 (C-1), 83.91 (C-2), 81.90 (C-3), 75.23 / 74.70 (CH Ph),
2
4.82 (C-5), 70.49 (C-4), 70.47 (α-CH ), 62.73 (C-6), 31.91 (β), 29.80 / 29.67 /
2
9.63 /29.62 / 29.58 / 29.45/ 29.35/ (bulk-CH ), 26.16 (γ), 22.69 (ω-1), 14.20 (ω).
2
+
HRMS: [M+Na] calcd. for C H O Na: 551.3349; found: 551.3356.
3
2
48
6
Dodecyl 2,3–O–dibenzyl–4,6–bis–O–[cynomethyl]–β–D–glucopyranoside 13
Compound 12 (2.6 g,5 mmol) was subjected to general procedure 4.1.1 to give 13
1
as a yellow syrup (2.5 g, 84%). [α] = +5.0 (c=1.0, CH Cl ). H NMR (400 MHz,
D
2
2
2
CDCl ) δ=7.38–7.25 (m, 10 H; Ph), 4.94 (d, 2 H, J =11.0 Hz; Bn), 4.70–4.63
3
Bn
2
(
2 d, 2 H, J =11.0 Hz; Bn),4.45–4.36 (dd, 2 H; CH C≡N), 4.37 (d, 1 H
Bn
2
2
3
2
J
=8.0 Hz; H-1), 3.34–3.27 (dd, 2 H J
=16 Hz; CH C≡N), 3.96–3.93 (dt,
1
,2
CH2C≡N
2
1
1
3
H; α-CH ), 3.93–3.86, (dd, 1 H, J
=11.0, 5.0 Hz; H- 6 eq), 3.82–3.77 (dd,
2
a
H-6a,b
2
3
3
H, J
=11.0, 6.8 Hz; H-6ax), 3.61 (t~dd, 1 H, J =8.0, J =9.0; H-2),
H-6a,b
1,2 2,3
.54–3.47 ( m, 2 H; H-4, α-CH ), 3.44–3.37 (m, H-3; H-5), 1.68–1.57 (m, 2 H;
2
b
3
β-CH ), 1.40- 1.18 (m, 18 H; bulk CH ), 0.86 (t, 3 H, J=8.0 Hz; CH ).
2
2
3
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
1
3
C NMR (100 MHz, CDCl ) δ = 128.64, 128.52, 128.25, 128.07, 127.98 (Ph),
3
1
7
16.28 /115.91 (2 C≡N), 103.72 (C-1), 84.04 (C-2), 82.05 (C-3), 77.45 (C-4),
5.62 / 74.76 (CH OR), 73.17 (C-5), 74.04 / 73.30 (Bn) 70.51 / 69.48 (C-6,
2
α-CH2), 57.56 / 56.97 (CH C≡N), 32.59 (β), 30.95, 29.78 / 29.72 / 29.53 /29.46 /
2
2
9.41 / 28.55 (bulk-CH ), 26.17 (γ), 22.79 (ω-1), 14.20 (ω).
2
+
HRMS: [M + Na] calcd. for C H N O Na: 629.3567; found: 629.3572.
3
6
50
2
6
Dodecyl 2,3–di–O–dibenzyl–4,6–bis–O–[2–aminoethyl]–β–D–glucopyranoside
1
4
Compound 13 (2.3 g, 3.8 mmol) was subjected to general reduction procedure
4
.1.2 to give amino-glycolipid 14 as a yellow syrup (2.07 g, 89%). [α] = + 12
D
1
(
(
c = 1.0, CH Cl ). H NMR (400 MHz, CDCl ) δ = 7.38–7.25 (m, 10 H; Ph), 4.94
2
2
3
2
2
d, 2 H, J = 11.0 Hz; Bn), 4.72–4.65 (2 d, 2 H, J = 11.0 Hz; Bn), 4.37 (d, 1
Bn
Bn
3
H, J = 8.0 Hz; H-1), 3.96–3.23 (mc, 12 H, 2 OCH , α-CH , H- 6 eq, H-6ax,
1
,2
2
2a
H-2, H-4, α-CH , H-3, H-5), 2.94-2.68 (mc, 4 H; CH NH ), 1.68–1.57 (m, 2 H;
2
b
2
2
3
β-CH ), 1.40–1.18 (m, 18 H; bulk-CH ), 0.86 (t, 3 H, J = 8.0 Hz; CH ).
2
2
3
1
3
C NMR (100 MHz, CDCl ) δ = 138.67, 138.52, 128.64, 128.52, 128.25,
3
1
/
28.07, 127.98 (Ph), 103.83 (C-1), 84.50 (C-2), 82.47 (C-3), 77.46 (C-4), 75.65
74.92 (CH OR), 76.62 (C-5), 74.04 / 73.30 (Bn) 70.31 / 70.00 (C-6,α-CH ),
2
2
4
2
2.66 / 41.77 (CH NH ), 32.59 (β), 30.95, 29.78 / 29.72 / 29.53 /29.46 / 29.41 /
2
2
8.55 (bulk-CH ), 26.17 (γ), 22.79 (ω-1), 14.20 (ω).
2
+
HRMS: [M + Na] calcd. for C H N O Na: 637.4193; found: 637.4199.
3
6
58
2
6
Dodecyl 2,3–di–O–dibenzyl–4,6–bis–O–[2–(2–chloroacetamido)ethyl]–β–D–
glucopyranoside 15
Compound 14 (2.33 g, 3.8 mmol) and chloroacetic anhydride (1.42 g, 8.36 mmol)
were subjected to general procedure 4.1.3 to give diamide 15 as a pale-yellow
1
wax (2.55 g, 88%). [α] = + 3.0 (c = 0.2, CHCl ). H NMR (400 MHz, CDCl )
D
3
3
δ = 7.36–7.26 (m, 10 H; Ph), 7.08 (br., 1 H; CONH), 7.02 (br., 1 H; CONH), 4.95
2
2
(
t⁓dd, 2 H, J = 11.0 Hz; Bn), 4.69 (2 d, 2 H, J = 11.0 Hz; Bn), 4.38 (d, 1
Bn Bn
3
H, J = 8.0 Hz; H-1), 4.05 (s, 2 H; CH Cl), 3.95–3.81 (m, 4 H; CH O, CH Cl),
1
,2
2
2
2
3
.78–3.27 (m, 14 H; H-2, H-3, H-4, H-5, H-6, CH O, α-CH , CH NHCO), 1.62
2 2 2
3
(
mc, 2 H; β-CH ), 1.40- 1.18 (m,18 H; bulk-CH ), 0.87 (t, 3 H, J = 8.0 Hz; CH ).
2
2
3
13
CNMR (100 MHz, CDCl ) δ = 166.24, 166.05 (CONH), 138.33,
3
1
8
38.31, 128.54, 128.49, 128.27, 128.06, 127.90, 127.83 (Ph), 103.79 (C-1),
4.28/82.25/77.06 (C-2, C- 3, C-4), 75.78/74.84 (Bn), 74.63 (C-5), 70.93/70.40
(
(
CH O), 70.12/69.50 (C-6,α- CH ), 42.72/42.66 (CH2Cl), 40.38/39.63
2 2
CH NH ), 32.00 (β), 30.32, 29.85/29.77/29.72/29.69/29.55/29.45/29.41 (bulk-
2
2
2
CH ), 26.27 (γ), 22.79 (ω-1), 14.23 (ω).
+
HRMS: [M + Na] calcd. for C H Cl N O Na: 789.3624; found: 789.3632.
4
0
60
2
2
8
1
3

K. J. Sabah et al.
Dodecyl 2,3–di–O–dibenzyl–4,6–[15–cr–5]thiadiamido–β–D–glucopyranoside 16
Compound 15 (0.40 g, 0.52 mmol) and Na S.9H O (0.19 g, 0.78 mmol) was
2
2
subjected to general procedure 4.1.4 to give 16 as a white solid (0.29 g, 77%).
1
[
α] = + 33.0 (c = 0.2, CHCl ). H NMR (400 MHz, CDCl ) δ = 7.38–7.24
D
3
3
(
m, 10 H; Ph), 7.07 (m, 1 H; CONH), 7.03 (m, 1 H; CONH), 5.00 (dd, 2 H,,
2
2
2
J
= 11.0, 10.8 Hz; Bn), 4.74 (d, 1 H, J = 10.8; Bn), 4.60 (d, 1 H, J = 11.0;
Bn
Bn
Bn
3
2
3
Bn), 4.32 (d, 1 H, J = 8.0 Hz; H-1), 3.90 (dt, 1 H,
J
= 9.1,
J
1
,2
α-CH2a,α-CH2b
=
2
6.8 Hz; α-CH ), 3.88–3.78 (m, 3 H; CH O, H- 6 eq), 3.77–3.63
α-CH2a,β-CH2a
(
2a
2
m, 4 H; CH O, H-4, H-6ax), 3.60–3.31 (m, 8 H; H-2, H-3, α-CH , CH NHCO,
2b
2
2
CH S), 3.2 (m, 1 H; H-5), 3.03 (m, 1 H; CH N), 2.92 (d, 1 H J
= 8.0 Hz;
2
2
2
CH2S
2
CH S), 2.58 (d, 1 H, J
= 8.0 Hz; CH S), 1.63 (mc, 2 H; β-CH ), 1.38–1.19
CH2S
2
2
3
(
m, 18 H; bulk-CH ), 0.87 (t, 3 H, J = 8.0 Hz; CH ).
2
3
1
3
C NMR (100 MHz, CDCl ) δ = 169.26, 168.94 (CONH), 138.35, 137.90,
3
1
28.75, 128.55, 128.40, 128.32, 127.89 (Ph), 103.87 (C-1), 84.33/82.37 (C-2,
C-3), 78.15 (C-4), 76.30 (Bn), 75.63 (C-5), 74.81 (Bn), 70.59 (α-CH ), 70.29/
2
7
0.27 (CH O), 68.98 (C-6), 4158/40.00 (CH NH), 36.79/36.22 (CH S), 32.00
2
2
2
(
(
β), 29.81, 29.77/ 29.69/29.66/29.54/29.45/ 29.41 (bulk-CH ), 26.26 (γ), 22.78
2
ω-1), 14.22 (ω).
+
HRMS: [M + Na] calcd. for C H N SO Na: 751.3988; found: 751.4080.
4
0
60
2
8
Dodecyl 2,3–di–O–dibenzyl–4,6–[15–cr–5]triazadiamido–β–D–glucopyranoside
1
7
Compound 15 (0.40 g, 0.52 mmol) and benzyl amine (0.07 g, 0.63 mmol) was
subjected to general procedure 4.1.5 to give 17 as a pale-yellow wax (0.25 g,
1
6
1%). [α] = –7.0 (c = 0.2, CHCl ). H NMR (400 MHz, CDCl ) δ = 7.39–7.20
D
3
3
(
m, 15 H; Ph), 7.11 (br., 1 H; CONH), 7.03 (br., 1 H; CONH), 4.95 (dd, 2 H,
2
2
J
= 11.0, 5.0 Hz; Bn), 4.68 (t≈dd, 2 H, J = 11.0, 5.0 Hz; Bn), 4.41 (d, 1
Bn
Bn
3
2
H, J = 8.0 Hz; H-1), 3.98–3.91 (m, 2 H; α-CH , H-6 eq), 3.78 (dd, 1 H,
J
1
,2
2a
3
=
2
11.0 Hz, J
= 8.0 Hz; H-6ax), 3.73–3.44 (m, 8 H; α-CH , H-2,
H-6 eq-H-6ax
H-6ax-5H 2b
BnN, CH O), 3.43–3.33 (m, 7 H; H-3, H-4, H-5, CH NH,), 3.25–3.02 (m, 4 H;
2
CH NCO), 1.63 (mc, 2 H; β-CH ), 1.38–1.19 (m,18 H; bulk-CH ), 0.87 (t, 3 H,
2
2
2
3
J = 8.0 Hz; CH ).
3
1
3
C NMR (100 MHz, CDCl ) δ = 169.26, 168.94 (CONH), 138.22, 137.91,
3
1
8
28.97, 128.55, 128.52, 128.28, 127.97, 127.93, 127.89 (Ph), 103.78 (C-1),
4.38/82.32/79.55 (C-2, C-3, C-4), 75.70/74.89 (Bn), 74.66 (C-5), 72.34/71.19
(
CH O), 70.46 (α-CH ), 70.22 (C-6), 60.34 (BnN), 59.39/58.45 (COCH N),
2
2
2
4
2
0.09/ 38.78 (CH NH), 32.00 (β), 29.87, 29.76/29.72/29.55/29.45 (bulk-CH ),
2
2
6.26 (γ), 22.78 (ω-1), 14.22 (ω).
+
HRMS: [M + Na] calcd. C H N O Na: 824.4894; found: 824.4890.
4
7
67
3
8
Supplementary Information The online version contains supplementary material available at https://doi.
org/10.1007/s11164-021-04432-8.
1
3

Synthesis of new chiral macrocycles-based glycolipids and…
Acknowledgment The grant from Ministry of Higher Education and the University of Malaya for the High
Impact Research Grant (UM.C/625/1/HIR/MOHE/05) is gratefully acknowledged.
Declarations
Conꢀict of interest The authors declare no conꢂict of interests.
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