Stereoselective synthesis and antiproliferative activity of the isomeric sphinganine analogues

Article abstract of DOI:10.1016/j.carres.2018.09.008

A flexible synthetic approach to biologically active sphingoid base-like compounds with a 3-amino-1,2-diol framework was achieved through a [3,3]-sigmatropic rearrangement and late stage olefin cross-metathesis as the key transformations. The stereochemistry of the newly created stereogenic centre was assigned via a single crystal X-ray analysis of the (4S,5R)-5-(hydroxymethyl)-4-vinyloxazolidine-2-thione. In order to rationalise the observed stereoselectivity of the aza-Claisen rearrangement, DFT calculations were carried out. The targeted isomeric sphingoid bases were screened in vitro for anticancer activity on a panel of seven human malignant cell lines. Cell viability experiments revealed that C₁₇-homologues are more active than their C₁₂ congeners.

Full text of DOI:10.1016/j.carres.2018.09.008

CarbohydrateResearch472(2019)76–85
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Stereoselective synthesis and antiproliferative activity of the isomeric
sphinganine analogues
Miroslava Čonkováa, Miroslava Martinkováa,∗, Jozef Gondaa, Dominika Jackováa,
Martina Bago Pilátováb, Daniel Kupkac, Dávid Jágerc
a Institute of Chemical Sciences, Department of Organic Chemistry, P.J. Šafárik University, Moyzesova 11, 040 01, Košice, Slovak Republic
b Institute of Pharmacology, Faculty of Medicine, P.J. Šafárik University, SNP 1, 040 66, Košice, Slovak Republic
c Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 040 01, Košice, Slovak Republic
A R T I C L E I N F O
A B S T R A C T
Keywords:
A flexible synthetic approach to biologically active sphingoid base-like compounds with a 3-amino-1,2-diol
framework was achieved through a [3,3]-sigmatropic rearrangement and late stage olefin cross-metathesis as the
key transformations. The stereochemistry of the newly created stereogenic centre was assigned via a single
crystal X-ray analysis of the (4S,5R)-5-(hydroxymethyl)-4-vinyloxazolidine-2-thione. In order to rationalise the
observed stereoselectivity of the aza-Claisen rearrangement, DFT calculations were carried out. The targeted
isomeric sphingoid bases were screened in vitro for anticancer activity on a panel of seven human malignant cell
lines. Cell viability experiments revealed that C17-homologues are more active than their C12 congeners.
Sphingolipids
Sphingoid bases
Isosphinganines
Aza-claisen rearrangement
Olefin cross-metathesis
Antiproliferative activity
1. Introduction
and antibacterial properties [9]. Surprisingly, 3 exhibited none of the
aforementioned activities [8,9]. These results indicate that the liberated
vicinal amino-alcohol motif is indeed important for the biological
Fig.D-1e)ryrtehprroe-Dseinhtysdaronspehairnligeorsiinnteer1me[d1i]at(ealisno thkneodwennoavso sbpihoisnygnatnhienseis,
[1b,2] of the more complex mammalian groups of sphingolipids, such
as sphingomyelins and glycosphingolipids, as well as being identified as
the structural backbone of the aforementioned classes in at least small
amounts. Sphinganine 1 (Fig. 1), together with the unsaturated wide-
spread D-erythro-sphingosine, inhibits protein kinase C (PKC) [3]. It was
found that 1 and its unnatural
profile of such compounds. Due to the promising activities associated
with the relatively simple structural features, numerous synthetic
methods towards 1 [10,11], 2 [10,11a,11f,11j,11n,12], 3 [9,11h,13-
14] and 4 [9,11h,13a,14-16] have been reported. The elaborated
methodologies have utilized both the Chiron Approach, as well as
asymmetric construction. Our ongoing interest in the total synthesis of
bioactive sphingolipid structures and their analogues [17] has stimu-
lated us to develop a convenient strategy leading to the construction of
the isomeric congeners of 1 and/or 4 (see compounds 5–8 in Scheme 1)
in order to obtain new derivatives for evaluation of their anticancer
profile, with the aim of searching for chemical entities with potential
therapeutic use. Besides the study of Génisson's group [18] oriented
towards “isophytosphingosines” and the work of Kokotos and cow-
orkers [19a], which has reported the remarkable in vitro cytotoxicity of
6 [19a] (Scheme 1) and its congeners on a panel of six different cancer
cell lines (A-2780, H-322, WiDr, UMSCC-22B, LL and C26-10), little is
known about the structural-activity relationships in this novel group of
the isomeric sphingoid bases, the general structure of which is depicted
in Fig. 1. With these factors in mind, we recently undertook the
synthesis and biological evaluation of 6 and 8 (Scheme 1) along with
their antipodes from D-isoascorbic acid [19b]. The remarkable
sphingosine kinase inhibitors [4D]/. L-threo-isomers are well-known
Furthermore,
sphingosine
2
(safingol) exhibits antineoplastic anLd-tharenoti-pdsihoyridartoic-
properties [5]. It is known that safingol possesses remarkable in vitro
anticancer activity and acts synergistically with various chemother-
apeutic agents [6]. Cammue at al [7a]. revealed the fungicidal activity
of the truncated C15e and C17-homologues of 1 against Candida albicans
and Candida glabrata, where both synthetic molecules were found to be
more potent than native dihydrosphingosine 1. Devi's group [7b] also
showed promising antifungal and antimicrobial activities of D-erythro-
congener of the natural sphinganine 1 with a C12 carbon backbone and
its several 1,2,3-triazole derivatives. A naturally occurring L-erythro-C12
analogue of 1, referred to as clavaminol H 3, was isolated from the
Mediterranean ascidian Clavelina phlegraea by Menna's group [8] in
2009, and its deacetylated form 4 demonstrates in vitro cytotoxic [8,9]
∗ Corresponding author.
E-mail address: miroslava.martinkova@upjs.sk (M. Martinková).
https://doi.org/10.1016/j.carres.2018.09.008
Received 7 September 2018; Received in revised form 27 September 2018; Accepted 27 September 2018
Availableonline28November2018
0008-6215/©2018ElsevierLtd.Allrightsreserved.

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
Fig. 1. Dihydrosphingosine 1, its analogues 2–4 and the
general structure of isomeric sphinganines.
Scheme 1. Retrosynthetic analysis of isomeric
sphingoid bases 5–8.
antiproliferative/cytotoxic potency of these aforementioned com-
pounds has prompted us to develop a more economic approach towards
them and their truncated analogues 5 and 7, which are expected to
have promising antifungal7a,b and/or antimicrobial activity [7b].
separable mixture of the α,β-unsaturated esters (E/Z)-12 [20].
The aforementioned olefination was carried out either in CH2Cl2 at
room temperature (E:Z = 40:60, combined yield of 79% over two steps)
or in benzene at reflux (E:Z = 72:28, 73%); their structures including
configuration of the double bonds, were determined by NMR analysis
(Jtrans = 15.6 Hz, Jcis = 11.6 Hz). After chromatographic separation, the
subsequent DIBAL-H reduction of (E)-12 and (Z)-12 gave the corre-
sponding alcohols (E)-16 [23] and (Z)-16 [23] in 88% and 90% isolated
yields, respectively (Scheme 3). To continue the synthesis, a two-step
sequence involving activation of the hydroxyl group of (E)-16 and (Z)-
16 with MsCl and followed by KSCN treatment, furnished the desired
thiocyanates (E)-11 (87%) and (Z)-11 (75%).
2. Results and discussion
2.1. Chemistry
The retrosynthetic strategy towards 5–8 is delineated in Scheme 1.
We planned to prepare our targeted molecules 5–6 and 7–8 from the
common oxazolidinones 9 and 10, respectively. The required long
chain segments could be installed in 9 and 10 via Grubbs' cross me-
tathesis chemistry. It was anticipated that cyclic carbamates 9 and 10
can be obtained by subjecting the allylic substrate E/Z-11 to the [3,3]-
sigmatropic rearrangement, which would be expected to stereo-
selectively create the new CeN bond. Thiocyanates E/Z-11 can be
prepared from the corresponding esters E/Z-12, which were envisioned
as arising from dimethyl L-tartrate. It should be noted that both deri-
vatives (E)-12 and (Z)-12 are commercially available compounds.
Seeing that they are too costly, we decided to prepare these isomers.
Our initial attempts to prepare 12 according to Hubschwerlen's original
protocol [20], which uses L-ascorbic acid as the starting material,
turned out to be ineffective. The corresponding esters 12 were isolated
With the substrates (E)-11 and (Z)-11 in hand, our focus then shifted
to the [3,3]-sigmatropic rearrangement to create the vicinal amino al-
cohol unit. The key aza-Claisen rearrangement of both thiocyanates 11
took place either at 70 °C or at 90 °C in n-heptane using the conven-
tional thermal conditions as well as microwave heating and provided
the corresponding isothiocyanates 17 and 18 as a separable mixture of
diastereoisomers in good yields (Table 1). During these experiments we
also recovered the starting material, either (E)-11 or a mixture of iso-
mers (E:Z ∼ 64:32) in approximately 7–32% yields. As shown in
Table 1, the best anti-17/syn-18 ratio was achieved using the thermally
driven reaction at 70 °C in the case of (Z)-11 (entries 9 and 10).
In order to rationalise the observed stereoselectivity in the [3,3]-
sigmatropic rearrangement of thiocyanates (E)-11 and (Z)-11, high-
level density functional theory (DFT) calculations [24], including
electron correlation effects, were carried out. A thorough conforma-
tional search was performed on all transition states, though only the
lowest energy conformers are discussed here. The rearrangements of
(Z)-11 and (E)-11 occur via transition states TS1/TS2 and TS3/TS4,
respectively (Scheme 3). The calculated diastereoisomeric ratio of
17:18 was 85:15 for the rearrangement of (Z)-11 and 90:10 for (E)-11
(both at 90 °C). These results are in relatively good agreement with the
experimental data (see Table 1), with the correct prediction of iso-
thiocyanate 17 as the major diastereoisomer.
vestigated as an alternative and proved to be a Lv-iTaabrlterastteartwinags mthaetenriianl-.
in a maximum overall yield of about 10%.
As seen in Scheme 2, our synthesis commenced with a gram-scale
preparation of the known protected L-threitol 13 [21] (63%, over two
steps). The obtained product 13 had NMR data, optical rotation and a
melting point in agreement with those reported in the literature [21b].
Exposure of 13 to acetone in the presence of p-TsOH and 4 Å molecular
sieves resulted in the formation of the acetonide 14 [21] in a 96% yield.
After deprotection of the O-benzyl group in 14, the obtained diol 15
[22] (96%) was subjected to oxidative fragmentation (NaIO4, CH2Cl2)
followed by the Wittig reaction using a stable ylide reagent to afford a
Scheme 2. Reagents and conditions: (a) acetone, p-
TsOH, 4 Å MS, rt; (b) H2, 10% Pd/C/20% Pd(OH)2/C
(2:1), EtOH, rt; (c) (i) NaIO4, CH2Cl2, rt; (ii)
Ph3P]CHCO2Et, CH2Cl2, rt or Ph3P]CHCO2Et,
benzene, reflux.
77

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
Scheme 3. Relative energies of transition states (in kcal/mol) and bond distances (in Å) are shown.
Reagents and conditions: (a) DIBAL-H, CH2Cl2, ‒50 °C; (b) (i) MsCl, Et3N, CH2Cl2, 0 °C; (ii) KSCN, MeCN, rt; (c) Table 1; (d) p-TsOH, MeOH, rt.
Table 1
[3,3]-Sigmatropic rearrangement of thiocyanates (E)-11 and (Z)-11.
Entry
Thiocyanate
Conditionsa
Time (h)
Ratiob
17:18
Yieldc (%)
Isolated thiocyanates (%)
1
(E)-11
(E)-11
(E)-11
(E)-11
(E)-11
(E)-11
(Z)-11
(Z)-11
(Z)-11
(Z)-11
(Z)-11
Δ, 90 °C
0.5
2
70:30
66:34
65:35
75:25
72:28
70:30
83:17
82:18
89:11
89:11
80:20
81
80
81
88
84
70
79
81
71
64
60
12d
7d
2
Δ, 90 °C
3
MW, 90 °C
Δ, 70 °C
0.4
6
9d
4
8d
5
Δ, 70 °C
3
14d
19d
14e
12e
22e
32e
27e
6
MW, 70 °C
Δ, 90 °C
1
7
2
8
MW, 90 °C
Δ, 70 °C
1
9
6
10
11
Δ, 70 °C
4
MW, 70 °C
4
a
b
c
d
e
In n-heptane.
Ratio in the crude reaction mixtures determined by 1H NMR.
Isolated combined yields.
Isolated (E)-11.
Isolated a mixture of thiocyanates (E/Z)-11 (E:Z ∼ 64:32). Determined by 1H NMR analysis.
78

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
derivatives 23 (83%) and 24 (86%). With the aim of being practical, we
tried to obtain 23 and 24 through a more economic sequence using the
tandem OCM/transfer hydrogenation [26]. When oxazolidinone 9 was
subjected to Grubbs’ catalyst-mediated cross metathesis with the cor-
responding alkenes (non-1-ene or tetradec-1-ene), followed by NaBH4
addition, products 23 and 24 were isolated in 73% and 76% yields,
respectively. On the other hand, the two-stage process mentioned above
led to their lower yields (to both 65% over two steps). In the case of 27
and 28 (Scheme 4), they were obtained in lower, but satisfying amounts
when compared with a two-step sequence (73% for 27 and 71% for 28
over two steps). Finally, the treatment of 23 and 24 with 6 M HCl re-
sulted in the production of the isomeric sphinganines 5 and 6 as HCl
salts in 83% and 85% isolated yields, respectively.
In a parallel fashion, the minor oxazolidinone 10 was elaborated
into the corresponding analogues 7 and 8 (Scheme 4). The spectro-
scopic and optical rotation data of 6 and 8 were in very good agreement
with the values reported in the literature for the same compounds
[19b].
Fig. 2. ORTEP structure of 20 showing the crystallographic numbering.
The configuration of the newly generated stereocentre in both aza-
Claisen products 17 and 18 was determined by their transformation to
oxazolidine-2-thiones 19 (90%) and 20 (90%), respectively. This
modification involved the acid hydrolysis of the protecting iso-
propylidene group, followed by the spontaneous intramolecular cycli-
zation providing derivatives 19 and 20 as crystalline compounds
(Scheme 3). The crystallographic analysis of thiocarbamate 20 con-
firmed its (4S,5R)-stereochemistry (Fig. 2), revealing that the minor
syn-diastereoisomer 18 possesses the same configuration.
2.2. Antiproliferative/cytotoxic activity
The final compounds 5 and 7 and also several intermediates of our
synthetic route (derivatives 17, 18, (E)-21 and (E)-22) were screened
for their antiproliferative/cytotoxic activities against seven different
human cancer cell lines ‒ MDA-MB-231 (mammary gland adenocarci-
noma), A-549 (non-small cell lung cancer), MCF-7 (mammary gland
adenocarcinoma), Caco-2 (human colon carcinoma), HCT-116 (human
colon carcinoma), HeLa (cervical adenocarcinoma), Jurkat (human
acute T-lymphoblastic leukaemia), and a non-malignant cell line NiH
3T3 (mouse fibroblasts), using MTT assay with triplicate experiments
[27]. The commercially available anticancer substance cisplatin was
included as a positive control, and the obtained results are summarised
in Table 2. Isothiocyanate 17 exhibited selective antiproliferative po-
tency against the MDA-MB-231 cell line with an IC50 value comparable
to those of cisplatin. To allow comparison, Table 2 also includes IC50
values for 6 and 8, which were prepared in our laboratory in a parallel
fashion [19b]. Whereas for compounds 5 and 7 cytotoxicity was sig-
nificantly reduced, isomeric sphinganines 6 and 8 displayed remarkable
activity for all tested cancer cell lines, revealing that antiproliferative/
cytotoxic profile was highly dependent on the chain length. In addition,
The stage was now set for the completion of construction of the
targeted isomeric sphinganine analogues 5–8. After treatment of 19 and
20 with mesitylnitrile oxide (MNO) in acetonitrile, the incorporation of
the long alkyl chains into the carbamates 9 and 10 was achieved via
cross-metathesis using Grubbs' second generation catalyst. The coupling
reaction of 9 with the commercial non-1-ene and tetradec-1-ene in re-
fluxing CH2Cl2 resulted in the production of the corresponding mixtures
of alkenes 21 and 22 in 78% and 75% combined yields, respectively
(Scheme 4). Because of overlap of the proton signals in the crude
aforementioned mixtures in both the CDCl3 and C6D6 solutions, it was
not possible to determine the corresponding ratio of the geometric
isomers. On the other hand, their repeated column chromatography
allowed the pure major isomers (E)-21 and (E)-22 to be isolated. The
subsequent catalytic hydrogenation of 21 and 22 was performed in the
presence of 5% Rh/Al2O3 [25] to furnish the corresponding saturated
Scheme 4. Reagents and conditions: (a) MNO, MeCN, rt; (b) Grubbs II, non-1-ene or tetradec-1-ene, CH2Cl2, reflux; (c) H2, 5% Rh/Al2O3, EtOAc or MeOH, rt; (d)
Grubbs II, non-1-ene or tetradec-1-ene, CH2Cl2, reflux, then NaBH4, MeOH, rt; (e) 6 M aq HCl, EtOH, 100 °C.
79

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
Table 2
Antiproliferative activities of compounds 5–8, 17, 18, (E)-21, (E)-22 on seven human cancer cell lines (MDA-MB-231, A-549, MCF-7, HCT-116, Caco-2, HeLa and
Jurkat) and non-malignant mouse fibroblasts NiH 3T3.
Compd no.
Cell line, IC50
SD (μmol × L−1
)
a
MDA-MB-231
A-549
MCF-7
HCT-116
Caco-2
HeLa
Jurkat
NiH 3T3
17
˂10
68.3
72.1
73.7
44.2
43.6
8.4
16.9
> 100
> 100
75.4
51.3
65.8
73.6
36.5
56.5
7.3
11.7
15
6.8
71.8
≥100
79.5
40.8
85.2
7.2
5.9
26
5.4
0.5
53.5
> 100
71.1
81.2
36.5
16.9
18
> 100
14.6
5.8
10.5
0.3
73.3
70.5
31.1
32.5
3.3
16
36
(E)-21
(E)-22
5
81.8
> 100
75.8
7.1
9.8
4.6
12.4
5.2
11.2
7.1
4.1
13.2
1.8
67.3
10.9
1.1
9.9
0.9
56
10.3
4.9
> 100
53.8
14.1
11.4
15.3
78.3
7.7
18.2
14.9
6 [19b]
7
0.9
0.5
0.1
0.6
2.3
1.5
7
1.3
7.6
0.1
81.8
6.3
7.1
1.6
0.5
33.2
3.7
20
2.1
0.2
79.6
7.3
5.1
0.1
0.3
72.8
1.4
23.3
1.3
0.5
56.5
1.7
2.2
1.2
0.3
> 100
4.9
59.5
0.7
16.2
3.1
23.2
0.7
1.9
8 [19b]
cisplatin
0.2
0.2
0.1
0.1
17.5
9.5
15.6
15.3
15.2
13.1
0.6
20.87
0.3
a
The potency of compounds was determined using MTT assay after 72 h incubation of cells and given as IC50 (concentration of a tested compound that decreased
number of viable cells to 50% relative to untreated control cells, see Section 4.2).
isodihydrosphingosine analogue 8 is significantly more potent on the
HCT-116 and Jurkat cell lines than derivative 6, whose IC50 values on
these cells are at least 5 and 10 × higher, respectively (Table 2). The
low potency of alkene (E)-22 relative to compound 6 or 8 emphasizes
the importance of the liberated vicinal amino-alcohol unit. Unsatura-
tion of the carbon backbone can also be detrimental for the cytotoxicity
in such series of compounds [8,28].
CD3OD (δ = 49.05). The multiplicity of the 13C NMR signals concerning
the 13Ce1H coupling was determined by the HSQC method. Chemical
shifts (in ppm) and coupling constants (in Hz) were obtained by first-
order analysis; assignments were derived from COSY and H/C corre-
lation spectra. Infrared (IR) spectra were measured with a Nicolet 6700
FT-IR spectrometer and expressed in v values (cm−1). High-resolution
mass spectra (HRMS) were recorded on a micrOTOF-Q II quadrupole-
time of flight hybrid mass spectrometer (Bruker Daltonics). Optical
rotations were measured on a P-2000 Jasco polarimeter and reported as
follows: [α]D (c in grams per 100 mL, solvent). Melting points were
recorded on a Kofler hot block, and are uncorrected. Microwave reac-
tions were carried out on a focused microwave system (CEM Discover).
The temperature content of the vessel was monitored using a calibrated
infrared sensor mounted under the vessel. At the end of all reactions the
contents of the vessel were cooled rapidly using a stream of compressed
air. Small quantities of reagents (μL) were measured with appropriate
syringes (Hamilton). All reactions were performed under an atmosphere
of nitrogen, unless otherwise noted.
3. Conclusion
In summary, we have accomplished the synthesis of isomeric
sphinganine analogues 5–8 starting from dimethyl L-tartrate. The key
transformation of our approach was the implementation of an amino-
bearing asymmetric centre through the [3,3]-sigmatropic rearrange-
ment of thiocyanates 11. In order to rationalise the stereochemical
outcome of the realised rearrangements, DFT calculations were carried
out. The alkyl chain of the common oxazolidinones 9 and 10 was ex-
tended via olefin cross-metathesis, thus completing the construction of
the targeted molecules. The several newly prepared compounds in-
cluding final isomeric sphingoid bases 5 and 7, were screened in vitro
for antiproliferative/cytotoxic activities against seven human cancer
cell lines. Cell viability experiments revealed that C17-homologues are
more active than their C12 congeners. On the other hand, the short-
chain analogues 5 and 7 were chosen as promising candidates for
evaluation of their antifungal and/or antimicrobial activity. Biological
screening is currently underway, and results will be reported in due
course.
4.2. (S)-2-(Benzyloxy)-2-[(S)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl]ethan-
1-ol (14) [21]
To a stirring solution of 13 [21] (2.0 g, 9.42 mmol) in dry acetone
(518 mL) were successively added 4 Å molecular sieves (2 g) and p-TsOH
(0.717 g, 3.77 mmol) at room temperature. After 12 h, the solid K2CO3
(1.7 g) was added, and the mixture was stirred for another 2 h. Filtration
through a small pad of Celite, followed by evaporation of the solvent left
a residue that was purified by flash chromatography on silica gel (n-
hexane/ethyl acetate, 3:1). This procedure yielded 2.27 g (96%) of
compound 14 as a colourless oil; [α]D27 −21.9 (c 1.6, CHCl3); lit [21a].
4. Experimental section
20
[α]D −17.0 (c 0.2, CHCl3, temperature 21–24 °C); lit [21b]. [α]D
4.1. General methods
−17.5 (c 1.08, CHCl3); IR (neat cm−1) 3447, 2985, 2933, 2880, 1454,
1370, 1253, 1210, 1156, 1048, 1027 cm−1
;
1H NMR (400 MHz, CDCl3)
All commercial reagents were used in the highest available purity
from Aldrich or Acros Organics without further purification. Solvents
were dried and purified before use according to standard procedures.
For flash column chromatography on silica gel, Kieselgel 60
(0.040–0.063 mm, 230–400 mesh, Merck) was used. Solvents for flash
chromatography (hexane, ethyl acetate, methanol, dichloromethane)
were distilled before use. Thin layer chromatography was run on Merck
silica gel 60 F254 analytical plates; detection was carried out with either
ultraviolet light (254 nm), or spraying with a solution of phosphomo-
lybdic acid, a basic potassium permanganate solution, or a solution of
concentrated H2SO4, with subsequent heating. 1H NMR and 13C NMR
spectra were recorded in CDCl3 and CD3OD on a Varian Mercury Plus
400 FT NMR (400.13 MHz for 1H and 100.61 MHz for 13C) spectro-
meter. For 1H, δ are given in parts per million (ppm) either relative to
TMS (δ = 0.0) as the internal standard or to the solvent signals CD3OD
(δ = 4.84 or δ = 3.31) and for 13C relative to CDCl3 (δ = 77.00) and
δ: 1.37 (s, 3H, CH3), 1.44 (s, 3H, CH3), 2.26 (br s, 1H, OH), 3.53–3.63 (m,
2H, H-1, H-2), 3.68–3.76 (m, 1H, H-1), 3.81 (dd, 1H, J = 7.0, 8.4 Hz, H-
5′), 4.01 (dd, 1H, J = 6.6, 8.4 Hz, H-5′), 4.25–4.34 (m, 1H, H-4′), 4.69 (d,
1H, J = 11.8 Hz, OCH2Ph), 4.77 (d, 1H, J = 11.8 Hz, OCH2Ph),
7.26–7.38 (m, 5H, Ph); 13C NMR (100 MHz, CDCl3) δ: 25.3 (CH3), 26.4
(CH3), 61.7 (C-1), 65.4 (C-5′), 72.7 (OCH2Ph), 76.6 (C-4′), 79.2 (C-2),
109.4 (Cq), 127.8 (3 × CHPh), 128.4 (2 × CHPh), 138.2 (Ci). ESI-HRMS:
m/z calcd for C14H21O4 [M + H]+ 253.143, found 253.141.
4.3. (S)-1-[(4′S)-2′,2′-Dimethyl-1′,3′-dioxolan-4′-yl]ethane-1,2-diol (15)
[22]
To a solution of 14 [21] (5.70 g, 22.6 mmol) in dry EtOH (180 mL)
was added a mixture of catalysts (10% Pd/C/20% Pd(OH)2/C, 2.4 g,
2:1). The resulting suspension was stirred at room temperature for 2 h
80

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
under an atmosphere of hydrogen, then filtered through a small pad of
Celite and concentrated. Chromatography of the residue on silica gel (n-
hexane/ethyl acetate, 1:2) furnished 3.51 g (96%) of compound 15 as a
colourless oil; [α]D25 +2.7 (c 0.78, CHCl3); lit [22]. [α]D20 +2.1 (c 1.0,
CHCl3). IR (neat cm−1) 3404, 2985, 2934, 2886, 1371, 1252, 1211,
1156, 1049; 1H NMR (400 MHz, CDCl3) δ: 1.37 (s, 3H, CH3), 1.45 (s,
3H, CH3), 3.62–3.67 (m, 2H, H-1, H-2), 3.70 (dd, 1H, J = 6.0, 12.9 Hz,
H-2), 3.86 (dd, 1H, J = 6.7, 8.3 Hz, H-5′), 4.06 (dd, 1H, J = 6.6, 8.3 Hz,
H-5′), 4.15–4.21 (m, 1H, H-4′); 13C NMR (100 MHz, CDCl3) δ: 25.2
(CH3), 26.4 (CH3), 64.1 (C-2), 65.8 (C-5′), 71.7 (C-1), 76.6 (C-4′), 109.6
(Cq). ESI-HRMS: m/z calcd for C7H15O4 [M + H]+ 163.096, found
163.092.
added dropwise to a solution of ester (E)-12 (2.28 g, 11.4 mmol) in dry
CH2Cl2 (52 mL) that had been pre-cooled to −50 °C. The resulting
mixture was stirred at the same temperature for 30 min before
quenching with MeOH (6.4 mL) to remove the excess hydride. The
whole mixture was then treated with a 30% K/Na tartrate solution
(170 mL) with vigorous stirring over 2 h at room temperature. The se-
parated aqueous phase was extracted with EtOAc (3 × 150 mL). The
combined organic layers were dried over Na2SO4, the solvents were
evaporated, and the residue was chromatographed on silica gel (n-
hexane/ethyl acetate, 1:1) to afford 1.59 g (88%) of compound (E)-16
26
as a colourless oil; [α]D −35.1 (c 0.70, CHCl3); lit [23]. [α]D −27.6
25
(c 0.29, CHCl3, temperature is not reported); lit [29]. [α]D +33.7 (c
1.0, CHCl3) for ent-(E)-16; IR (neat cm−1) 3404, 2985, 2934, 2870,
1370, 1213, 1154, 1052, 1008; 1H NMR (400 MHz, CDCl3) δ: 1.39 (s,
3H, CH3), 1.43 (s, 3H, CH3), 2.06 (br s, 1H, OH), 3.58–3.64 (m, 1H, H-
5′), 4.10 (dd, 1H, J = 6.2, 8.2 Hz, H-5′), 4.13–4.19 (m, 2H, 2 × H-1),
4.50–4.58 (m, 1H, H-4′), 5.68–5.76 (m, 1H, H-3), 5.92–6.00 (m, 1H, H-
2); 13C NMR (100 MHz, CDCl3) δ: 25.8 (CH3), 26.6 (CH3), 62.5 (C-1),
69.3 (C-5′), 76.4 (C-4′), 109.3 (Cq), 128.3 (C-3), 133.5 (C-2). ESI-HRMS:
m/z calcd for C8H14O3 [M + Na]+ 181.084, found 181.085.
4.4. Ethyl (R,E)-3-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)acrylate (E−12)
[20] and ethyl (R,Z)-3-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)acrylate (Z-
12) [20]
A solution of 15 (0.25 g, 1.54 mmol) in CH2Cl2 (8.3 mL) was treated
with a solution of NaIO4 (0.38 g, 1.78 mmol) in water (1.7 mL) at room
temperature. After being stirred for 30 min, the insoluble parts were
filtered off, and the filtrate was diluted with CH2Cl2. The separated
aqueous phase was then extracted with CH2Cl2 (10 mL). The combined
organic layers were dried over Na2SO4, and the solvent was evaporated.
The obtained crude aldehyde [20] was used immediately in the next
reaction without purification.
4.6. (R,Z)-3-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)prop-2-en-1-ol (Z-16)
[23]
By the same procedure as described for the preparation of (E)-16
from (E)-12, compound (Z)-12 (1.77 g, 8.8 mmol) was transformed to
alcohol (Z)-16 (colourless oil, 1.25 g, 90%, n-hexane/ethyl acetate,
1:1); [α]D25 −15.2 (c 0.56, CHCl3); lit [23]. [α]D −16.5 (c 0.22, CHCl3,
temperature is not reported). IR (neat cm−1) 3405, 2985, 2935, 2871,
1371, 1212, 1154, 1053; 1H NMR (400 MHz, CDCl3) δ: 1.40 (s, 3H,
CH3), 1.43 (s, 3H, CH3), 2.22 (br s, 1H, OH), 3.54–3.60 (m, 1H, H-5′),
4.10 (dd, 1H, J = 6.1, 8.2 Hz, H-5′), 4.18 (dd, 1H, J = 6.0, 13.3 Hz, H-
1), 4.30 (dd, 1H, J = 7.0, 13.3 Hz, H-1), 4.81–4.91 (m, 1H, H-4′),
Wittig reaction in CH2Cl2To a solution of the crude aldehyde (0.2 g,
1.54 mmol) in CH2Cl2 (10 mL) was added the ylide reagent,
Ph3P]CHCO2Et, (1.2 g, 3.46 mmol). After stirring at room temperature
for 30 min, the solvent was evaporated in vacuo, and the residue was
subjected to flash chromatography on silica gel (n-hexane/ethyl
acetate, 25:1) to afford 0.243 g (79%) of a mixture of α,β-unsaturated
esters (E/Z-12).
Wittig reaction in benzene: To a solution of Ph3P]CHCO2Et (1.2 g,
3.46 mmol) in dry benzene (5 mL) was added a solution of the crude
aldehyde (0.2 g, 1.54 mmol) in the same solvent (5 mL), and the mix-
ture was heated at reflux for 1 h. After the solvent was removed, the
residue was purified by flash chromatography on silica gel (n-hexane/
ethyl acetate, 25:1) to give 0.225 g (73%) of a mixture of the corre-
sponding esters (E/Z-12).
5.53–5.60 (m, 1H, H-3), 5.84 (ddd, 1H, J = 6.0, 7.0, 11.2 Hz, H-2); 13
C
NMR (100 MHz, CDCl3) δ: 25.9 (CH3), 26.7 (CH3), 58.5 (C-1), 69.5 (C-
5′), 71.8 (C-4′), 109.4 (Cq), 129.4 (C-3), 133.1 (C-2). ESI-HRMS: m/z
calcd for C8H14NaO3 [M + Na]+ 181.084, found 181.085.
4.7. (R,E)-2,2-dimethyl-4-(3′-thiocyanatoprop-1′-en-1′-yl)-1,3-dioxolane
The repeated chromatography allowed the separation of both geo-
metric isomers, which were isolated as colourless oils.
(E−11)
Ester (E)-12: [α]D27 −47.7 (c 0.44, CHCl3); lit [20]. [α]D20 ‒46.0 (c
1.0, CHCl3); IR (neat cm−1); 2985, 2937, 2875, 1717, 1661, 1370,
1301, 1257, 1213, 1174, 1154, 1058, 1032, 976; 1H NMR (400 MHz,
CDCl3) δ: 1.30 (t, 3H, J = 7.1 Hz, CH3), 1.41 (s, 3H, CH3), 1.45 (s, 3H,
CH3), 3.68 (dd, 1H, J = 7.1, 8.3 Hz, H-5′), 4.16–4.25 (m, 3H, CH2, H-
5′), 4.64–4.70 (m, 1H, H-4′), 6.10 (dd, 1H, J = 1.4, 15.6 Hz, H-2), 6.88
(dd, 1H, J = 5.7, 15.6 Hz, H-3); 13C NMR (100 MHz, CDCl3) δ: 14.2
(CH3), 25.7 (CH3), 26.4 (CH3), 60.5 (CH2), 68.8 (C-5′), 74.9 (C-4′),
110.2 (Cq), 122.4 (C-2), 144.6 (C-3), 166.0 (C]O). ESI-HRMS: m/z
calcd for C10H16NaO4 [M + Na]+ 223.094, found 223.096.
To a solution of (E)-16 (1.59 g, 10.05 mmol) in dry CH2Cl2 (86 mL),
that had been pre-cooled to 0 °C, was added Et3N (2.08 mL,
15.07 mmol), followed by addition of MsCl (1.15 mL, 15.07 mmol).
After being stirred for 30 min at 0 °C, the solvent was evaporated and
the residue was treated with Et2O (86 mL). The solid parts were filtered
off, washed with Et2O, and the filtrate was concentrated. The obtained
crude mesylate (2.37 g, 10.05 mmol) was dissolved in acetonitrile
(80 mL). To this solution, anhydrous KSCN (1.68 g, 17.08 mmol) was
added at room temperature, and the resulting mixture was stirred for
6 h before evaporating of the solvent. Chromatography of the residue
on silica gel (n-hexane/ethyl acetate, 7:1) gave 1.74 g (87%) of com-
pound (E)-11 as a colourless oil; [α]D27 −56.1 (c 0.66, CHCl3); IR (neat
cm−1) 2985, 2935, 2874, 2153, 1370, 1212, 1153, 1056, 966; 1H NMR
(400 MHz, CDCl3): δ 1.40 (s, 3H, CH3), 1.44 (s, 3H, CH3), 3.52–3.68 (m,
3H, 2 × H-3′, H-5), 4.16 (dd, 1H, J = 6.3, 8.3 Hz, H-5), 4.55–4.60 (m,
1H, H-4), 5.81–5.95 (m, 2H, H-1′, H-2′); 13C NMR (100 MHz, CDCl3) δ:
25.7 (CH3), 26.5 (CH3), 35.3 (C-3′), 69.4 (C-5), 75.6 (C-4), 109.7 (Cq),
111.4 (SCN), 125.3 (C-2′), 135.2 (C-1′). ESI-HRMS: m/z calcd for
C9H13NNaO2S [M + Na]+ 222.056, found 222.058.
27
20
Ester (Z)-12: [α]D −126.4 (c 0.5, CHCl3); lit [20]. [α]D ‒126.0
(c 5.2, CHCl3); IR (neat cm−1) 2986, 2937, 1717, 1412, 1381, 1372,
1188, 1155, 1059, 1030; 1H NMR (400 MHz, CDCl3) δ: 1.29 (t, 3H,
J = 7.1 Hz, CH3), 1.39 (s, 3H, CH3), 1.45 (s, 3H, CH3), 3.63 (dd, 1H,
J = 6.7, 8.3 Hz, H-5′), 4.18 (q, 2H, J = 7.1 Hz, CH2), 4.38 (dd, 1H,
J = 6.9, 8.3 Hz, H-5′), 5.46–5.54 (m, 1H, H-4′), 5.85 (dd, 1H, J = 1.7,
11.6 Hz, H-2), 6.36 (dd, 1H, J = 6.6, 11.6 Hz, H-3); 13C NMR (100 MHz,
CDCl3) δ: 14.1 (CH3), 25.4 (CH3), 26.5 (CH3), 60.4 (CH2), 69.4 (C-5′),
73.5 (C-4′), 109.7 (Cq), 120.8 (C-2), 149.2 (C-3), 165.6 (C]O). ESI-
HRMS: m/z calcd for C10H16NaO4 [M + Na]+ 223.094, found 223.096.
4.8. (R,Z)-2,2-dimethyl-4-(3′-thiocyanatoprop-1′-en-1′-yl)-1,3-dioxolane
4.5. (R,E)-3-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)prop-2-en-1-ol (E−16)
(Z-11)
[23]
Using the same reaction sequence as employed for the conversion of
DIBAL-H (9.5 mL, 34.2 mmol, ∼1.2 M solution in toluene) was
(E)-16 to (E)-11, compound (Z)-16 (1.25 g, 7.9 mmol) was converted to
81

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
thiocyanate (Z)-11 (colourless oil, 1.18 g (75%), n-hexane/ethyl
3.67–3.75 (m, 2H, 2 × H-6), 4.62–4.66 (m, 1H, H-4), 4.93 (ddd, 1H,
J = 4.5, 6.1, 9.3 Hz, H-5), 5.32–5.38 (m, 2H, 2 × H-8), 5.92 (ddd, 1H,
J = 7.3, 10.3, 17.4 Hz, H-7); 13C NMR (100 MHz, CD3OD) δ: 61.3 (C-6),
61.7 (C-4), 86.8 (C-5), 120.3 (C-8), 133.1 (C-7), 190.7 (C]S). ESI-
HRMS: m/z calcd for C6H10NO2S [M + H]+ 160.043, found 160.044.
acetate, 7:1); [α]D +126.1 (c 0.82, CHCl3); IR (neat cm−1) 2986,
26
2935, 2872, 2154, 1380, 1371, 1212, 1153, 1055; 1H NMR (400 MHz,
CDCl3) δ: 1.40 (s, 3H, CH3), 1.44 (s, 3H, CH3), 3.55–3.60 (m, 1H, H-3′),
3.65 (dd, 1H, J = 7.6, 8.4 Hz, H-5), 3.87–3.92 (m, 1H, H-3′), 4.18 (dd,
1H, J = 6.2, 8.4 Hz, H-5), 4.78–4.83 (m, 1H, H-4), 5.74–5.83 (m, 2H, H-
1′, H-2′); 13C NMR (100 MHz, CDCl3) δ: 25.8 (CH3), 26.6 (CH3), 30.7 (C-
3′), 69.7 (C-5), 71.3 (C-4), 109.8 (Cq), 111.5 (SCN), 125.6 (C-2′), 133.9
(C-1′). ESI-HRMS: m/z calcd for C9H13NNaO2S [M + Na]+ 222.056,
found 222.058.
4.11. (4S,5R)-5-(hydroxymethyl)-4-vinyloxazolidine-2-thione (20)
By the same procedure as described for the conversion of 17 to 19,
diastereomeric isothiocyanate 18 (0.70 g, 3.50 mmol) was transformed
to oxazolidine-2-thione 20 (white crystals, 0.50 g, 90%, n-hexane/ethyl
26
4.9. (R)-4-[(R)-1′-Isothiocyanatoallyl]-2,2-dimethyl-1,3-dioxolane (17)
and (R)-4-[(S)-1′-isothiocyanatoallyl]-2,2-dimethyl-1,3-dioxolane (18)
acetate, 1:1); mp 130–133 °C; [α]D −144.6 (c 0.48, MeOH); IR (neat
cm−1) 3315, 3185, 2927, 1522, 1379, 1257, 1176, 1093, 1000; 1H
NMR (400 MHz, CD3OD) δ: 3.67 (dd, 1H, J = 4.2, 12.8 Hz, H-6), 3.82
(dd, 1H, J = 3.4, 12.8 Hz, H-6), 4.39–4.42 (m, 1H, H-4), 4.51–4.55 (m,
1H, H-5), 5.28–5.30 (m, 1H, H-8), 5.33–5.38 (m, 1H, H-8), 5.89 (ddd,
1H, J = 7.2, 10.2, 17.2 Hz, H-7); 13C NMR (100 MHz, CD3OD) δ: 61.6
(C-4), 62.1 (C-6), 89.5 (C-5), 119.3 (C-8), 136.4 (C-7), 190.6 (C]S).
ESI-HRMS: m/z calcd for C6H10NO2S [M + H]+ 160.043, found
160.042.
4.9.1. Conventional method (general procedure)
The corresponding thiocyanate (E)-11 or (Z)-11 (0.10 g, 0.50 mmol)
was dissolved in n-heptane (3.5 mL), and the resulting solutions were
stirred and heated under a nitrogen atmosphere (for the temperatures
and reaction times, see Table 1). After cooling to room temperature, the
solvent was evaporated, and the residue was subjected to flash chro-
matography on silica gel (n-hexane/ethyl acetate, 30:1) to provide the
rearranged products 17 and 18 (for the combined yields, see Table 1).
4.12. (4R,5R)-5-(hydroxymethyl)-4-vinyloxazolidin-2-one (9)
4.9.2. Microwave-assisted synthesis (general procedure)
Mesitylnitrile oxide (1.80 g, 11.22 mmol) was added to a solution of
19 (1.49 g, 9.35 mmol) in dry MeCN (91 mL), and the resulting mixture
was stirred for 0.5 h at room temperature. After the solvent was eva-
porated, the residue was subjected to flash chromatography on silica gel
(n-hexane/ethyl acetate, 1:3) to give 1.28 g (96%) of compound 9 in the
form of white crystals; mp 102–105 °C; [α]D26 −7.0 (c 0.37, MeOH); IR
(neat cm−1) 3438, 3239, 2932, 1754, 1408, 1319, 1245, 1087; 1H NMR
(400 MHz, CD3OD) δ: 3.63–3.71 (m, 2H, 2 × H-6), 4.45–4.49 (m, 1H,
H-4), 4.69–4.73 (m, 1H, H-5), 5.29 (d, 1H, J = 10.3 Hz, H-8cis), 5.35 (d,
1H, J = 17.2 Hz, H-8trans), 5.94 (ddd, 1H, J = 7.2, 10.3, 17.2 Hz, H-7);
13C NMR (100 MHz, CD3OD) δ: 58.2 (C-4), 61.8 (C-6), 81.4 (C-5), 119.3
(C-8), 134.6 (C-7), 161.6 (C]O). ESI-HRMS: m/z calcd for C6H10NO3
[M + H]+ 144.066, found 144.067.
Thiocyanate (E)-11 or (Z)-11 (0.10 g, 0.5 mmol) was weighed in a
10-mL glass pressure microwave tube equipped with a magnetic stirbar.
n-Heptane (3.5 mL) was added, the tube was closed with a silicon
septum, and the resulting mixture was subjected to microwave irra-
diation (for the temperatures and reaction times, see Table 1). After
being cooled to room temperature, the solvent was taken down, and the
residue was purified by flash chromatography on silica gel (n-hexane/
ethyl acetate, 30:1) to afford isothiocyanates 17 and 18 (for the com-
bined yields, see Table 1).
Requiring greater amounts of the pure products 17 and 18, they
were prepared on a multigram scale by the conventional method in n-
heptane at 70 °C starting from (E)-11.
Diastereoisomer 17: colourless oil; [α]D26 +42.6 (c 0.68, CHCl3); IR
(neat cm−1) 2986, 2935, 2885, 2048, 1372, 1209, 1151, 1069; 1H NMR
(400 MHz, CDCl3) δ: 1.36 (s, 3H, CH3), 1.49 (s, 3H, CH3), 3.93 (dd, 1H,
J = 5.1, 8.8 Hz, H-5), 4.08 (dd, 1H, J = 6.4, 8.8 Hz, H-5), 4.13–4.17 (m,
1H, H-4), 4.40–4.43 (m, 1H, H-1′), 5.35 (dd, 1H, J = 1.0, 10.3 Hz, H-
3′cis), 5.47 (dd, 1H, J = 1.0, 16.9 Hz, H-3′trans), 5.81 (ddd, 1H, J = 5.1,
10.3, 16.9 Hz, H-2′); 13C NMR (100 MHz, CDCl3) δ: 25.0 (CH3), 26.5
(CH3), 61.5 (C-1′), 65.8 (C-5), 77.1 (C-4), 110.6 (Cq), 118.5 (C-3′),
131.4 (C-2′), 135.0 (NCS). ESI-HRMS: m/z calcd for C9H13NNaO2S [M
+ Na]+ 222.056, found 222.057.
4.13. (4S,5R)-5-(hydroxymethyl)-4-vinyloxazolidin-2-one (10)
By the same procedure as described for the preparation of 9, com-
pound 20 (0.49 g, 3.07 mmol) was converted into derivative 10 (col-
26
ourless oil, 0.40 g, 91%, n-hexane/ethyl acetate, 1:3); [α]D −87.5 (c
0.16, MeOH); IR (neat cm−1) 3402, 3275, 2925, 1720, 1390, 1223,
1096, 1026; 1H NMR (400 MHz, CD3OD) δ: 3.64 (dd, 1H, J = 4.1,
12.6 Hz, H-6), 3.78 (dd, 1H, J = 3.2, 12.6 Hz, H-6), 4.20–4.28 (m, 2H,
H-4, H-5), 5.24 (d, 1H, J = 10.2 Hz, H-8cis), 5.33 (d, 1H, J = 17.0 Hz, H-
8trans), 5.90 (ddd, 1H, J = 6.7, 10.2, 17.0 Hz, H-7); 13C NMR (100 MHz,
CDCl3) δ: 56.4 (C-4), 61.5 (C-6), 82.5 (C-5), 118.7 (C-8), 135.8 (C-7),
159.4 (C]O). ESI-HRMS: m/z calcd for C6H10NO3 [M + H]+ 144.066,
found 144.067.
Diastereoisomer 18: colourless oil, [α]D26 −98.2 (c 0.78, CHCl3); IR
(neat cm−1) 2986, 2935, 2885, 2044, 1371, 1211, 1152, 1065; 1H NMR
(400 MHz, CDCl3) δ: 1.36 (s, 3H, CH3), 1.49 (s, 3H, CH3), 3.83 (dd, 1H,
J = 5.2, 8.8 Hz, H-5), 4.06 (dd, 1H, J = 6.3, 8.8 Hz, H-5), 4.19–4.26 (m,
2H, H-1′, H-4), 5.37 (d, 1H, J = 10.3 Hz, H-3′), 5.46 (d, 1H,
J = 16.9 Hz, H-3′), 5.78–5.86 (m, 1H, H-2′); 13C NMR (100 MHz,
CDCl3) δ: 25.0 (CH3), 26.4 (CH3), 61.9 (C-1′), 65.8 (C-5), 77.1 (C-4),
110.6 (Cq), 119.3 (C-3′), 131.4 (C-2′), 135.3 (NCS). ESI-HRMS: m/z
calcd for C9H13NNaO2S [M + Na]+ 222.056, found 222.057.
4.14. (4R,5R)-5-(Hydroxymethyl)-4-[(E)-non-1′-en-1′-yl]oxazolidin-2-
one (E−21) and (4R,5R)-5-(hydroxymethyl)-4-[(Z)-non-1′-en-1′-yl]
oxazolidin-2-one (Z-21)
Non-1-ene (0.60 mL, 3.50 mmol) and Grubbs catalyst II (59 mg,
0.07 mmol) were successively added to a solution of oxazolidinone 9
(0.10 g, 0.70 mmol) in dry CH2Cl2 (15 mL). After being stirred at reflux
for 1 h, the solvent was evaporated, and the residue was chromato-
graphed on silica gel (n-hexane/ethyl acetate, 1:1) to furnish 0.13 g
(78%) of a mixture of olefins 21 as a white solid. Repeated chromato-
graphy allowed the separation of (E)-21 as the major product in the
form of white crystals.
4.10. (4R,5R)-5-(hydroxymethyl)-4-vinyloxazolidine-2-thione (19)
Isothiocyanate 17 (2.08 g, 10.4 mmol) was dissolved in dry MeOH
(190 mL) at room temperature and p-TsOH (0.20 g, 1.05 mmol) was
added. After being stirred at the same temperature for 17 h, the solvent
was evaporated in vacuo, and the residue was chromatographed
through a short column of silica gel (n-hexane/ethyl acetate, 1:1) to
furnish 1.49 g (90%) of compound 19 as white crystals; mp 98–100 °C;
[α]D26 +42.7 (c 0.26, MeOH); IR (neat cm−1) 3410, 3221, 2924, 1505,
1386, 1265, 1176, 1142, 1053, 1003; 1H NMR (400 MHz, CD3OD) δ:
21
(E)-isomer 21: mp 109–112 °C; [α]D −12.6 (c 0.35, CHCl3); IR
(neat cm−1) 3417, 3253, 2924, 2851, 1755, 1412, 1247, 1080, 1037,
963; 1H NMR (400 MHz, CD3OD) δ: 0.90 (t, 3H, J = 6.9 Hz, CH3),
82

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
1.31–1.44 (m, 10H, 5 × CH2), 2.06–2.11 (m, 2H, CH2), 3.65–3.67 (m,
2H, 2 × H-6), 4.40–4.44 (m, 1H, H-4), 4.67 (td, 1H, J = 5.4, 8.6 Hz, H-
5), 5.51 (tdd, 1H, J = 1.3, 7.9, 15.3 Hz, H-1′), 5.72–5.80 (m, 1H, H-2′);
13C NMR (100 MHz, CD3OD) δ: 14.5 (CH3), 23.8 (CH2), 30.2 (CH2),
30.3 (2 × CH2), 33.1 (CH2), 33.2 (CH2), 57.9 (C-4), 62.0 (C-6), 81.9 (C-
5), 126.1 (C-1′), 137.1 (C-2′), 161.7 (C]O). ESI-HRMS: m/z calcd for
C13H24NO3 [M + H]+ 242.175, found 242.177.
1:1) was prepared by the catalytic hydrogenation in MeOH (4.8 mL)
from a mixture of olefins 22 (75 mg, 0.24 mmol) according to the
procedure used to convert 21 to 23.
4.17.2. Modification of 9 to 24
To a solution of 9 (0.15 mg, 1.05 mmol) in dry CH2Cl2 (22 mL) were
successively added tetradec-1-ene (1.3 mL, 5.25 mmol) and Grubbs II
(45 mg, 0.053 mmol). After being stirred at reflux until no starting
material was observed (judged by TLC, 1 h), the mixture was allowed to
cool to room temperature. Then, MeOH (4.5 mL) and NaBH4 (0.396 g,
10.5 mmol) were added, and the resulting mixture was stirred for 2 h.
After washing with water and extraction with CH2Cl2 (3 × 20 mL), the
combined organic layers were dried over Na2SO4 and concentrated. The
residue was chromatographed on silica gel (n-hexane/ethyl acetate,
4.15. (4R,5R)-5-(hydroxymethyl)-4-[(E)-tetradec-1′-en-1′-yl]oxazolidin-
2-one (E−22) and (4R,5R)-5-(hydroxymethyl)-4-[(Z)-tetradec-1′-en-1′-
yl]oxazolidin-2-one (Z-22)
Using the same reaction conditions as in the previous case, com-
pound 9 (0.14 g, 0.978 mmol) was converted into a mixture of olefins
22 (0.23 g, 75%, n-hexane/ethyl acetate, 1:1). Repeated chromato-
graphy allowed the separation of (E)-22 as the major product as white
crystals.
21
1:1) to give 0.25 g (76%) of compound 24; mp 111–113 °C; [α]D
−10.0 (c 0.15, CHCl3); IR (neat cm−1) 3410, 3281, 2914, 2848, 1758,
1469, 1047; 1H NMR (400 MHz, CDCl3) δ: 0.88 (t, 3H, J = 6.7 Hz, CH3),
1.26–1.37 (m, 24H, 12 × CH2), 1.52–1.58 (m, 2H, CH2), 2.05–2.08 (m,
1H, OH); 3.78–3.94 (m, 3H, H-4, 2 × H-6); H-6), 4.66–4.71 (m, 1H, H-
5), 5.52 (br s, 1H, NH); 13C NMR (100 MHz, CDCl3) δ: 14.1 (CH3), 22.7
(CH2), 26.7 (CH2), 29.4 (3 × CH2), 29.5 (CH2), 29.6 (4 × CH2), 29.7
(2 × CH2), 31.9 (CH2), 54.7 (C-4), 60.8 (C-6), 79.6 (C-5), 158.6 (C]O).
ESI-HRMS: m/z calcd for C18H36NO5 [M + H]+ 314.269, found
314.271.
21
(E)-isomer 22: mp 112–115 °C; [α]D −14.2 (c 0.24, CHCl3); IR
(neat cm−1) 3271, 2916, 2848, 2532, 1756, 1478, 1033; 1H NMR
(400 MHz, CDCl3) δ: 0.88 (t, 3H, J = 6.8 Hz, CH3), 1.26–1.41 (m, 20H,
10 × CH2), 1.92–1.95 (m, 1H, OH); 2.04–2.09 (m, 2H, CH2), 3.70–3.84
(m, 2H, 2 × H-6), 4.40–4.44 (m, 1H, H-4), 4.69–4.74 (m, 1H, H-5), 5.03
(br s, 1H, NH), 5.50 (dd, 1H, J = 8.5, 15.5 Hz, H-1′), 5.74–5.81 (m, 1H,
H-2′); 13C NMR (100 MHz, CDCl3, 50 °C) δ: 14.0 (CH3), 22.7 (CH2), 28.9
(CH2), 29.2 (CH2), 29.3 (CH2), 29.4 (CH2), 29.6 (2 × CH2), 29.7
(2 × CH2), 31.9 (CH2), 32.1 (CH2), 56.7 (C-4), 61.6 (C-6), 79.8 (C-5),
124.1 (C-1′), 137.5 (C-2′), 158.1 (C]O). ESI-HRMS: m/z calcd for
4.18. (2R,3R)-3-Aminododecane-1,2-diol hydrochloride (5)
C
18H34NO3 [M + H]+ 312.253, found 312.252.
A solution of 23 (30 mg, 0.136 mmol) in EtOH (0.6 mL) was treated
with 6 M aq HCl solution (6.4 mL). The resulting mixture was stirred
and heated at 100 °C for 21 h. After evaporating of the solvents, the
solid residue was washed several times with dry Et2O and dried under
high vacuum for 6 h. This procedure yielded 28 mg (90%) of compound
4.16. (4R,5R)-5-(hydroxymethyl)-4-nonyloxazolidin-2-one (23)
4.16.1. Modification of 21 into 23
21
5% Rh/Al2O3 (27 mg) was added to a solution of a mixture of al-
kenes 21 (0.13 g, 0.54 mmol) in dry EtOAc (11 mL), and the resulting
suspension was stirred at room temperature under an atmosphere of
hydrogen. After completion of the reaction (2 h, judged by TLC), the
mixture was filtered through a small pad of Celite and concentrated.
Flash chromatography of the residue on silica gel (n-hexane/ethyl
acetate, 1:1) furnished 0.109 g (83%) of compound 23 as white crystals.
5 as a white amorphous solid; [α]D +6.4 (c 0.44, MeOH); IR (neat
cm−1) 3331, 3025, 2915, 2848, 1508, 1463, 1050; 1H NMR (400 MHz,
CD3OD) δ: 0.91 (t, 3H, J = 7.0 Hz, CH3), 1.32–1.56 (m, 14H, 7 × CH2),
1.62–1.78 (m, 2H, CH2), 3.30–3.36 (m, 1H, H-3 + CD3OD), 3.65 (dd,
1H, J = 5.3, 11.4 Hz, H-1), 3.72 (dd, 1H, J = 4.9, 11.4 Hz, H-1),
3.81–3.85 (m, 1H, H-2); 13C NMR (100 MHz, CD3OD) δ: 14.5 (CH3),
23.7 (CH2), 26.8 (CH2), 29.1 (CH2), 30.4 (CH2), 30.5 (CH2), 30.6 (CH2),
30.7 (CH2), 33.1 (CH2), 56.1 (C-3), 63.7 (C-1), 71.1 (C-2). ESI-HRMS:
m/z calcd for C12H27NNaO2 [M + Na]+ 240.193, found 240.195.
4.16.2. Modification of 9 into 23
A solution of 9 (50 mg, 0.35 mmol) in dry CH2Cl2 (7.5 mL) was
successively treated with non-1-ene (0.3 mL, 1.75 mmol) and Grubbs II
(15 mg, 0.018 mmol). After being stirred at reflux until no starting
material was observed (judged by TLC, 2 h), the mixture was allowed to
cool to room temperature, and then, MeOH (1.5 mL) and NaBH4
(0.132 g, 3.5 mmol) were added. After 3 h with stirring, the reaction
mixture was partitioned between water (10 mL) and CH2Cl2 (10 mL).
The separated aqueous phase was washed with the further portions of
CH2Cl2 (2 × 10 mL). The combined organic layers were dried over
Na2SO4 and concentrated. The residue was subjected to flash chroma-
4.19. (2R,3R)-3-Aminoheptadecane-1,2-diol hydrochloride (6) [19b]
Using the same procedure as described for the preparation of 5,
compound 24 (23 mg, 0.073 mmol) was converted to derivative 6
21
(white amorphous solids, 20 mg, 87%); [α]D +12.9 (c 0.28, MeOH);
20
lit [19b]. [α]D +12.3 (c 0.26, MeOH); IR (neat cm−1) 3339, 3039,
2914, 2847, 1462; 1H NMR (400 MHz, CD3OD) δ: 0.89 (t, 3H,
J = 6.7 Hz, CH3), 1.29–1.54 (m, 24H, 12 × CH2), 1.60–1.76 (m, 2H,
CH2), 3.28–3.35 (m, 1H, H-3 + CD3OD), 3.63 (dd, 1H, J = 5.3,
11.4 Hz, H-1), 3.71 (dd, 1H, J = 4.9, 11.4 Hz, H-1), 3.80–3.84 (m, 1H,
H-2); 13C NMR (100 MHz, CD3OD) δ: 14.5 (CH3), 23.7 (CH2), 26.8
(CH2), 29.1 (CH2), 30.5 (2 × CH2), 30.6 (CH2), 30.7 (CH2), 30.8
(5 × CH2), 33.1 (CH2), 56.1 (C-3), 63.7 (C-1), 71.1 (C-2). Anal. Calcd
for C17H38ClNO2: C, 63.03; H, 11.82; N, 4.32. Found: C, 63.16; H,
11.91; N, 4.21. ESI-HRMS: m/z calcd for C17H38NO2 [M + H]+
288.290, found 288.292.
tography on silica gel (n-hexane/ethyl acetate, 1:1) to give 62 mg (73%)
of 23; mp 115–116 °C; [α]D −2.3 (c 0.26, CHCl3); IR (neat cm−1
)
21
3413, 3282, 2920, 2849, 1754, 1420, 1250, 1097, 1034; 1H NMR
(400 MHz, CDCl3) δ: 0.88 (t, 3H, J = 6.6 Hz, CH3), 1.26–1.43 (m, 14H,
7 × CH2), 1.51–1.60 (m, 2H, CH2), 2.55–2.58 (m, 1H, OH), 3.79–3.95
(m, 3H, 2 × H-6, H-4), 4.66–4.71 (m, 1H, H-5), 6.16 (br s, 1H, NH); 13
C
NMR (100 MHz, CDCl3) δ: 14.1 (CH3), 22.6 (CH2), 26.6 (CH2), 29.2
(CH2), 29.4 (2 × CH2), 29.5 (CH2), 29.6 (CH2), 31.8 (CH2), 54.8 (C-4),
60.7 (C-6), 79.7 (C-5), 159.2 (C]O). ESI-HRMS: m/z calcd for
4.20. (4S,5R)-5-(Hydroxymethyl)-4-[(E)-non-1′-en-1′-yl]oxazolidin-2-
one (E−25) and (4S,5R)-5-(hydroxymethyl)-4-[(Z)-non-1′-en-1′-yl]
oxazolidin-2-one (Z-25)
C
13H26NO3 [M + H]+ 244.191, found 244.194.
4.17. (4R,5R)-5-(hydroxymethyl)-4-tetradecyloxazolidin-2-one (24)
Using the same procedure as described for the preparation of 21,
compound 10 (55 mg, 0.38 mmol) was converted into a mixture of
olefins 25 (72 mg, 79%, n-hexane/ethyl acetate, 1:1). Repeated
4.17.1. Modification of 22 to 24
Compound 24 (white crystals, 65 mg, 86%, n-hexane/ethyl acetate,
83

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
chromatography allowed the separation of (E)-25 as the major product
as white crystals; mp 54–56 °C; [α]D21 − 70.3 (c 0.58, CHCl3); IR (neat
cm−1) 3432, 3311, 2952, 2919, 2854, 1760, 1698, 1663, 1467, 1418,
1341, 1217, 1098, 1032; 1H NMR (400 MHz, CDCl3) δ: 0.88 (t, 3H,
J = 6.9 Hz, CH3), 1.27–1.40 (m, 10H, 5 × CH2), 2.01–2.07 (m, 2H,
CH2), 2.63 (br s, 1H, OH), 3.61–3.70 (m, 1H, H-6), 3.89–3.93 (m, 1H,
H-6), 4.22–4.28 (m, 2H, H-4, H-5), 5.39–5.44 (m, 1H, H-1′), 5.49 (br s,
1H, NH), 5.75 (td, 1H, J = 6.8, 15.1 Hz, H-2′); 13C NMR (100 MHz,
CDCl3) δ: 14.1 (CH3), 22.6 (CH2), 28.8 (CH2), 29.1 (2 × CH2), 31.8
(CH2), 32.0 (CH2), 56.1 (C-4), 61.5 (C-6), 82.8 (C-5), 127.1 (C-1′),
136.7 (C-2′), 158.6 (C]O). ESI-HRMS: m/z calcd for C13H24NO3 [M +
H]+ 242.175, found 242.173.
[α]D21 − 38.9 (c 0.70, CHCl3); IR (neat cm−1) 3286, 3199, 2914, 2847,
1720, 1467, 1406, 1251, 1094; 1H NMR (400 MHz, CDCl3) δ: 0.88 (t,
3H, J = 6.8 Hz, CH3), 1.26–1.33 (m, 24H, 12 × CH2), 1.52–1.62 (m,
2H, CH2), 2.81 (t, 1H, J = 6.4 Hz, OH), 3.62–3.73 (m, 2H, H-4, H-6),
3.83–3.88 (m, 1H, H-6), 4.26 (ddd, 1H, J = 3.2, 4.6, 5.6 Hz, H-5), 5.99
(br s, 1H, NH); 13C NMR (100 MHz, CDCl3) δ: 14.1 (CH3), 22.7 (CH2),
25.2 (CH2), 29.3 (2 × CH2), 29.4 (CH2), 29.5 (CH2), 29.6 (3 × CH2),
29.7 (2 × CH2), 31.9 (CH2), 35.4 (CH2), 53.7 (C-4), 62.9 (C-6), 82.6 (C-
5), 159.1 (C]O). ESI-HRMS: m/z calcd for C18H36NO3 [M + H]+
314.269, found 314.275.
4.24. (2R,3S)-3-Aminododecane-1,2-diol hydrochloride (7)
4.21. (4S,5R)-5-(hydroxymethyl)-4-[(E)-tetradec-1′-en-1′-yl]oxazolidin-
2-one (E−26) and (4S,5R)-5-(hydroxymethyl)-4-[(Z)-tetradec-1′-en-1′-
yl]oxazolidin-2-one (Z-26)
Compound 27 (40 mg, 0.164 mmol) was dissolved in a minimum
volume of EtOH (0.7 mL) and then treated with a 6 M aq solution of HCl
(7.7 mL). The resulting mixture was stirred and heated at 100 °C for
30 h. After the solvent was removed, the residue was further washed
three times with Et2O and dried under high vacuum for 10 h. This
procedure yielded 35 mg (83%) of compound 7 as white amorphous
solids; [α]D21 +1.9 (c 0.46, MeOH); IR (neat cm−1) 3388, 3120, 2998,
2950, 2918, 2849, 1484, 1374, 1105, 1072; 1H NMR (400 MHz,
CD3OD) δ: 0.90 (t, 3H, J = 6.8 Hz, CH3), 1.30–1.48 (m, 14H, 7 × CH2),
1.58–1.67 (m, 1H, CH2), 1.71–1.80 (m, 1H, CH2), 3.26–3.29 (m, 1H, H-
3), 3.66–3.71 (m, 3H, H-2, 2 × H-1); 13C NMR (100 MHz, CD3OD) δ:
14.5 (CH3), 23.7 (CH2), 26.4 (CH2), 30.4 (CH2), 30.5 (CH2), 30.6 (CH2),
30.7 (CH2), 31.3 (CH2), 33.1 (CH2), 55.0 (C-3), 65.0 (C-1), 70.5 (C-2).
ESI-HRMS: m/z calcd for C12H27NNaO2 [M + Na]+ 240.193, found
240.193.
According to the same procedure as employed for the conversion of
9 to 22, compound 10 (0.10 g, 0.70 mmol) was transformed to a mix-
ture of alkenes 26 (0.16 g, 73%, n-hexane/ethyl acetate, 1:1). Repeated
chromatography allowed the separation of (E)-26 as the major product
in the form of white crystals; mp 72–74 °C; [α]D21 − 53.6 (c 0.56,
CHCl3); IR (neat cm−1) 3433, 3308, 2952, 2919, 2845, 1770, 1687,
1668, 1467, 1420, 1214, 1099, 1032; 1H NMR (400 MHz, CDCl3) δ:
0.88 (t, 3H, J = 6.7 Hz, CH3), 1.26–1.37 (m, 20H, 10 × CH2),
2.01–2.06 (m, 2H, CH2), 3.13 (br s, 1H, OH), 3.63–3.66 (m, 1H, H-6),
3.89–3.92 (m, 1H, H-6), 4.20–4.30 (m, 2H, H-4, H-5), 5.38–5.44 (m,
1H, H-1′), 5.74 (td, 1H, J = 6.7, 15.3 Hz, H-2′), 5.82 (br s, 1H, NH); 13
C
NMR (100 MHz, CDCl3) δ: 14.1 (CH3), 22.7 (CH2), 28.8 (CH2), 29.1
(CH2), 29.3 (CH2), 29.4 (CH2), 29.6 (3 × CH2), 29.7 (CH2), 31.9 (CH2),
32.0 (CH2), 56.1 (C-4), 61.5 (C-6), 82.8 (C-5), 127.1 (C-1′), 136.7 (C-
2′), 158.6 (C]O). ESI-HRMS: m/z calcd for C18H34NO3 [M + H]+
312.253, found 312.251.
4.25. (2R,3S)-3-Aminoheptadecane-1,2-diol hydrochloride (8) [19b]
According to the same procedure as employed for the conversion of
27 to 7, compound 28 (40 mg, 0.128 mmol) was modified into deri-
21
vative 8 (white amorphous solid, 33 mg, 88%); [α]D +2.2 (c 0.18,
MeOH); lit [19b]. [α]D +1.4 (c 0.28, MeOH); IR (neat cm−1) 3383,
21
4.22. (4S,5R)-5-(hydroxymethyl)-4-nonyloxazolidin-2-one (27)
3116, 2917, 2848, 1486, 1085; 1H NMR (400 MHz, CD3OD) δ: 0.90 (t,
3H, J = 6.8 Hz, CH3), 1.29–1.48 (m, 24H, 12 × CH2), 1.57–1.66 (m,
1H, CH2), 1.71–1.80 (m, 1H, CH2), 3.24–3.29 (m, 1H, H-3), 3.66–3.71
(m, 3H, H-2, 2 × H-1); 13C NMR (100 MHz, CD3OD) δ: 14.5 (CH3), 23.8
(CH2), 26.5 (CH2), 30.5 (CH2), 30.6 (2 × CH2), 30.7 (CH2), 30.8
(3 × CH2), 30.9 (2 × CH2), 31.4 (CH2), 33.1 (CH2), 55.0 (C-3), 65.1 (C-
1), 70.5 (C-2). ESI-HRMS: m/z calcd for C17H37NNaO2 [M + Na]+
310.272, found 310.273.
4.22.1. Modification of 25 to 27
According to the same procedure as employed for the conversion of
21 to 23, compound 25 (52 mg, 0.215 mmol) was transformed to de-
rivative 27 (white crystals, 48 mg, 92%, n-hexane/ethyl acetate, 1:1).
4.22.2. Modification of 10 to 27
Using the same procedure as described for the conversion of 9 to 23,
compound 10 (40 mg, 0.28 mmol) was transformed to derivative 27
(46 mg, 68%, n-hexane/ethyl acetate, 1:1); mp 74–75 °C; [α]D21 − 55.8
(c 0.98, CHCl3); IR (neat cm−1) 3288, 3199, 2919, 2851, 1721, 1406,
1378, 1258, 1086; 1H NMR (400 MHz, CDCl3) δ: 0.88 (t, 3H,
J = 6.8 Hz, CH3), 1.26–1.31 (m, 14 H, 7 × CH2), 1.56–1.60 (m, 2H,
CH2), 2.42 (br s, 1H, OH), 3.65–3.73 (m, 2H, H-4, H-6), 3.84–3.88 (m,
1H, H-6), 4.27 (ddd, 1H, J = 3.2, 4.7, 5.7 Hz, H-5), 5.63 (br s, 1H, NH);
13C NMR (100 MHz, CDCl3) δ: 14.1 (CH3), 22.7 (CH2), 25.2 (CH2), 29.2
(CH2), 29.3 (CH2), 29.4 (2 × CH2), 31.8 (CH2), 35.4 (CH2), 53.7 (C-4),
63.0 (C-6) 82.5 (C-5), 158.8 (C]O). ESI-HRMS: m/z calcd for
C13H26NO3 [M + H]+ 244.191, found 244.193.
4.26. Antiproliferative/cytotoxic activity
4.26.1. Cell culture
The following human cancer cell lines were used for this study: A-
549 (non-small cell lung cancer), HeLa (cervical adenocarcinoma),
MCF-7 (mammary gland adenocarcinoma), MDA-MB-231 (mammary
gland adenocarcinoma), HCT-116 (human colon carcinoma), Caco-2
(human colon carcinoma), Jurkat (acute T-lymphoblastic leukaemia)
and non-cancerous cell line NiH 3T3 (mouse fibroblasts). A-549, HCT-
116, MCF-7, MDA-MB-231, Caco-2, Jurkat and HeLa cells were main-
tained in RPMI 1640 medium. NiH 3T3 cell line was maintained in
growth medium consisting of high glucose Dulbecco's Modified Eagle
Medium. Both of these media were supplemented with Glutamax, and
with 10% (V/V) foetal calf serum, penicillin (100 IU × mL−1), and
streptomycin (100 mg × mL−1) (all from Invitrogen, Carlsbad, CA
USA), in the atmosphere of 5% CO2 in humidified air at 37 °C. Cell
viability, estimated by the trypan blue exclusion, was greater than 95%
before each experiment.
4.23. (4S,5R)-5-(hydroxymethyl)-4-tetradecyloxazolidin-2-one (28)
4.23.1. Modification of 26 to 28
Using the same procedure as described for the preparation of 24,
compound 26 (0.10 g, 0.32 mmol) was transformed to derivative 28
(white crystals, 98 mg, 97%, n-hexane/ethyl acetate, 1:1).
4.23.2. Modification of 10 to 28
According to the same procedure employed for the transformation
of 9 to 24, compound 10 (50 mg, 0.35 mmol) was converted into de-
rivative 28 (72 mg, 66%, n-hexane/ethyl acetate, 1:1); mp 80–84 °C;
4.26.2. Cytotoxicity assay
The cytotoxic effect of the tested compounds was studied using the
colorimetric microculture assay with the MTT endpoint [27]. The
84

M. Čonková et al.
CarbohydrateResearch472(2019)76–85
amount of MTT reduced to formazan was proportional to the number of
viable cells. Briefly, 5 × 103 cells were plated per well in 96-well poly-
styrene microplates (Sarstedt, Germany) in the culture medium con-
(j) M. Mukherjee, Y. Zhou, A. Gupta, Y. Guan, W.D. Wulff, Eur. J. Org Chem.
(2014) 1386–1390;
(k) G. Silveira-Dorta, O.J. Donadel, V.S. Martín, J.M. Padrón, J. Org. Chem. 79
(2014) 6775–6782;
taining tested chemicals at final concentrations 10−4–10−6 mol × L−1
.
(l) C. Siciliano, A. Barattucci, P. Bonaccorsi, M.L. Di Gioia, A. Leggio, L. Minuti, E.
Romio, A. Temperini, J. Org. Chem. 79 (2014) 5320–5326;
(m) P. Wisse, H. Gold, M. Mirzaian, M.J. Ferraz, G. Lutteke, R.J.B.H.N. van der
Berg, H. van den Elst, J. Lugtenburg, G.A. van der Marel, J.M.F.G. Aerts, J.D.C.
Code, H.S. Overkleeft, Eur. J. Org Chem. (2015) 2661–2677;
(n) P. Das, S. Kundooru, A.K. Shaw, RSC Adv. 6 (2016) 14505–14511
[12] (a) L.H. Zhang, D.C. Oniciu, R. Mueller, B.H. McCosar, E. Pop, ARKIVOC (2005)
285–291;
After 72 h incubation, 10 μL of MTT (5 mg × mL−1) were added into
each well. After an additional 4 h, during which insoluble formazan was
formed, 100 μL of 10% (m/m) sodium dodecylsulfate were added into
each well and another 12 h were allowed for the formazan to be dis-
solved. The absorbance was measured at 540 nm using the automated
uQuant™ Universal Microplate Spectrophotometer (Biotek Instruments
Inc., Winooski, VT USA). The blank corrected absorbance of the control
wells was taken as 100% and the results were expressed as a percentage
of the control.
(b) Y.S. Tian, J.E. Joo, V.T. Pham, W.H. Ham, K.Y. Lee, Arch Pharm. Res. (Seoul)
30 (2007) 167–171;
(c) A. Sharma, S. Gamre, S. Chattopadhyay, Tetrahedron Lett. 48 (2007) 633–634;
(d) N. Kim, S.H. Lee, S.K. Namgoong, Bull. Kor. Chem. Soc. 30 (2009) 695–699;
(e) P. Kumar, A. Dubey, V.G. Puranik, Org. Biomol. Chem. 8 (2010) 5074–5086;
(f) M.V. Rao, K.S. Reddy, B.V. Rao, Tetrahedron Lett. 53 (2012) 5993–5995;
(g) D.D. Qin, W. Yu, J.D. Zhou, Y.C. Zhang, Y.P. Ruan, Z.H. Zhou, H.B. Chen,
Chem. Eur J. 19 (2013) 16541–16544;
Acknowledgement
(h) H. Zhu, P. Chen, G. Liu, J. Am. Chem. Soc. 136 (2014) 1766–1769;
(i) J. Weng, L.J. Huang, L. Long, L.Y. Xu, G. Lu, Tetrahedron Lett. 57 (2016)
2554–2557;
Financial support from Slovak Grant Agency VEGA, grants no. 1/
0047/18 and no. 1/0546/16 is gratefully acknowledged. The present
work was also supported the by the Slovak Research and Development
Agency under contract no. APVV-14-0883, and by the Operational
Programme Research and Development through the project: ITMS
26220120064. We thank assoc. professor Juraj Kuchár for his assistance
in X-ray measurements.
(j) Y. Garg, R. Kaur, S.K. Pandey, Eur. J. Org Chem. (2017) 6700–6707.
[13] (a) A.M. Zaed, A. Sutherland, Org. Biomol. Chem. 9 (2011) 8030–8037;
(b) B. Thirupathi, Y. Bharath, D.K. Mohapatra, ARKIVOC (2016) 162–171.
[14] There are works in the literature, which recently communicated the construction of
clavaminol H 3 (see reference 11d) and deacetyl clavaminol H 4 (see references 11c
and 11d). reportIt Should Be Noted that Aforementioned Reports Published
Syntheses of the Corresponding Antipodes of 3 and 4 with the (2S,3R)-configured
Vicinal Amino-alcohol Moiety.
[15] T. Jin, L. Zhao, M. Huang, Y. Yue, Z.B. Zheng, W.H. Ham, Tetrahedron: Asymmetry
28 (2017) 725–729.
[16] B.S. Chen, L.H. Yang, J.L. Ye, T. Huang, Y.P. Ruan, J. Fu, P. Huang, Q. Eur. J. Med.
Chem. 46 (2011) 5480–5486.
Appendix A. Supplementary data
[17] (a) M. Martinková, J. Gonda, K. Pomikalová, J. Kožíšek, J. Kuchár, Carbohydr. Res.
346 (2011) 1728–1738;
Supplementary data to this article can be found online at https://
doi.org/10.1016/j.carres.2018.09.008.
(b) M. Martinková, K. Pomikalová, J. Gonda, M. Vilková, Tetrahedron 69 (2013)
8228–8244;
(c) M. Martinková, E. Mezeiová, J. Gonda, D. Jacková, K. Pomikalová,
Tetrahedron: Asymmetry 25 (2014) 750–766;
References
(d) M. Martinková, E. Mezeiová, M. Fabišíková, J. Gonda, M. Pilátová, J. Mojžiš,
Cabohydr. Res. 402 (2015) 6–24;
[1] (a) S.H. Pruett, A. Bushnev, K. Hagedorn, M. Adiga, C.A. Haynes, M.C. Sullards,
D.C. Liotta, A.H. Merrill Jr., J. Lipid Res. 49 (2008) 1621–1639;
(b) A.H. Merrill Jr., Chem. Rev. 111 (2011) 6387–6422.
(e) K. Stanková, M. Martinková, J. Gonda, M. Bago, M. Pilátová, G. Gönciová,
Tetrahedron: Asymmetry 26 (2015) 1394–1407;
(f) E. Mezeiová, M. Martinková, K. Stanková, M. Fabišíková, J. Gonda, M. Pilátová,
G. Gönciová, Carbohydr. Res. 423 (2016) 70–81;
[2] T. Wennekes, R.J.B.H.N. van den Berg, R.G. Boot, G.A. van der Marel,
H.S. Overkleeft, J.M.F.G. Aerts, Angew. Chem. Int. Ed. 48 (2009) 8848–8868 and
references cited therein.
(g) M. Fabišíková, M. Martinková, S. Hirková, J. Gonda, M. Bago Pilátová,
G. Gönciová, Carbohydr. Res. 435 (2016) 26–36.
[3] C. Rodriguez-Lafrasse, R. Rousson, S. Valla, P. Antignac, P. Louisot, M.T. Vanier,
Biochem. J. 325 (1997) 787–791.
[18] A. Rives, C. Baudoin-Deboux, N. Saffon, N. Andrieu-Abadie, Y. Génisson, Org.
Biomol. Chem. 9 (2011) 8163–8170.
[4] K.A.O. Gandy, L.M. Obeid, Biochim. Biophys. Acta 1831 (2013) 157–166.
[5] USP Dictionary of USAN and International Drug Names, US Pharmcopia, Rockville,
MD, 2000, p. 636.
[19] (a) J.M. Padrón, V.S. Martin, D. Hadjipavlou-Litina, C. Noula, V. Constantinou-
Kokotou, G.J. Peters, G. Kokotos, Bioorg. Med. Chem. Lett 9 (1999) 821–826;
(b) M. Fabišíková, M. Martinková, J. Gonda, D. Jacková, M. Bago Pilatová,
J. Kuchár, Carbohydr. Res. 468 (2018) 51–63.
[6] (a) G.K. Shwartz, J. Jiang, D. Kelsen, A.P. Albino, J. Natl. Cancer Inst. 85 (1993)
402–407;
[20] C. Hubschwerlen, Synthesis (1986) 962–964.
(b) J. Coward, G. Ambrosini, E. Musi, J.P. Truman, A. Haimowitz-Friedman,
J.C. Allegoog, E. Wang, A.H. Merrill, G.K. Schwartz, Authopagy 5 (2009) 184–193;
(c) T. Noda, S. Iwai, M. Hamada, Y. Fujita, Y. Yura, Apoptosis 14 (2009) 287–289;
(d) M.A. Dickson, R.D. Carvajal, A.H. Merrill Jr., M. Gonen, L.M. Cane,
G.K. Schwartz, Clin. Canc. Res. 17 (2011) 2484–2492.
[21] (a) F. Sánchez-Sancho, S. Valverde, B. Herradón, Tetrahedron: Asymmetry 7
(1996) 3209–3246;
(b) A. El-Batta, Synth. Commun. 43 (2013) 2457–2463.
[22] Y.H. Chen, Y.T. Tseng, T.Y. Luh, Chem. Commun. (1996) 327–328.
[23] T. Suzuki, E. Sato, S. Kamada, H. Tada, K. Unno, J. Chem. Soc., Perkin Trans. 1
(1986) 387–391.
[7] (a) K. Thevissen, U. Hillaert, E.M.K. Meert, K.K. Chow, B.P.A. Cammue,
S.V. Calenbergh, I.E.J.A. François, Bioorg. Med. Chem. Lett 18 (2008) 3728–3730;
(b) T.V.K. Reddy, A. Jyotsna, B.L.A.P. Devi, R.B.N. Prasad, Y. Poornachandra,
C.G. Kumar, Eur. J. Med. Chem. 118 (2016) 98–106.
[24] Gaussian 03, Revision C.02, M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria,
M.A. Robb, J.R. Cheeseman, J.A. Montgomery Jr., T. Vreven, K.N. Kudin,
J.C. Burant, J.M. Millam, S.S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi,
G. Scalmani, N. Rega, G.A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota,
R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai,
M. Klene, X. Li, J.E. Knox, H.P. Hratchian, J.B. Cross, V. Bakken, C. Adamo,
J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi,
C. Pomelli, J.W. Ochterski, P.Y. Ayala, K. Morokuma, G.A. Voth, P. Salvador,
J.J. Dannenberg, V.G. Zakrzewski, S. Dapprich, A.D. Daniels, M.C. Strain, O. Farkas,
D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J.V. Ortiz, Q. Cui,
A.G. Baboul, S. Clifford, J. Cioslowski, B.B. Stefanov, G. Liu, A. Liashenko,
P. Piskorz, I. Komaromi, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng,
A. Nanayakkara, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong,
C. Gonzalez, J.A. Pople, Gaussian, Inc., Wallingford CT, (2004).
[25] J.L. Abad, I. Nieves, P. Rayo, J. Casas, G. Fabriàs, A. Delgado, J. Org. Chem. 78
(2013) 5858–5866.
[8] A. Aiello, E. Fatorrusso, A. Giordano, M. Menna, C. Navarrete, E. Muñoz,
Tetrahedron 65 (2009) 4384–4388.
[9] T.V.K. Reddy, A. Jyotsna, B.L.A.P. Devi, R.B.N. Prasad, Y. Poornachandra,
C.G. Kumar, Eur. J. Med. Chem. 120 (2016) 86–96.
[10] For a review on syntheses of d-erythro-dihydrosphingosine, its stereoisomers in-
cluding safingol, see: A.R. Howell, R.C. So, S.K. Richardson, Tetrahedron 60 (2004)
11327–11347.
[11] For recent syntheses of sphinganine 1, see.
(a) H.P. Kokatla, R. Sagar, Y.D. Vankar, Tetrahedron Lett. 49 (2008) 4728–4730;
(b) E. Abraham, S.G. Davies, N.L. Millican, R.L. Nicholson, P.L. Roberts, A.D.
Smith, Org. Biomol. Chem. 6 (2008) 1655–1664;
(c) C. Séguin, F. Ferreira, C. Botuha, F. Chemla, A. Pérez-Luna, J. Org. Chem. 74
(2009) 6986–6992;
(d) R. Ait-Youcef, X. Moreau, C. Greck, J. Org. Chem. 75 (2010) 5312–5315;
(e) F. Sarabia, C. Vivar-García, M. García-Castro, C. García-Ruiz, F. Martín-Gálvez,
A. Sánchez-Ruiz, S. Chammaa, Chem. Eur J. 18 (2012) 15190–15201;
(f) M.E. Jung, S.W. Yi, Tetrahedron Lett. 53 (2012) 4216–4220;
(g) E.D.D. Calder, A.M. Zaed, A. Sutherland, J. Org. Chem. 78 (2013) 7223–7233;
(h) M. Pandey, P.S. Chowdhury, A.K. Dutta, P. Kumar, S. Pal, RSC Adv. 3 (2013)
15442–15448;
[26] (a) G.K. Zieliński, K. Grela, Chem. Eur J. 22 (2016) 1–16;
(b) T. Connolly, Z. Wang, M.A. Walker, I.M. McDonald, K.M. Peese, Org. Lett. 16
(2014) 4444–4447.
[27] T. Mosmann, J. Immunol. Meth. 65 (1983) 55–63.
[28] A. Aiello, E. Fattorrusso, A. Giordano, M. Menna, C. Navarrete, E. Muñoz, Bioorg.
Med. Chem. 16 (2007) 2920–2926.
[29] M.D. Swift, A. Sutherland, Tetrahedron 64 (2008) 9521–9527.
(i) T.J. Devi, B. Saikia, N.C. Barua, Tetrahedron 69 (2013) 3817–3822;
85