Synthesis and growth inhibitory properties of glycosides of 1-O- hexadecyl-2-O-methyl-sn-glycerol, analogs of the antitumor ether lipid ET- 18-OCH3 (edelfosine)

Article abstract of DOI:10.1021/jm960164j

Glycosylated antitumor ether lipids (GAELs), analogs of 1-O-octadecyl- 2-O-methyl-sn-glycero-3-phosphocholine (1, ET-18-OCH₃, edelfosine), were synthesized in good overall yields by glycosylation of 1-O-alkyl-2-O- methyl-sn-glycerol and tested for in vitro antineoplastic activity against a variety of murine and human tumor cell lines. Stereospecific glycosylation was achieved by the use of 2-O-acetyl-3,4,6-tri-O-benzylglucopyranosyl and - mannopyranosyl trichloroacetimidates as donors, with trimethylsilyl trifluoromethanesulfonate as catalyst in the presence of molecular sieves at -78 °C. The GAELs differ from 1 in having the sn-3-phosphocholine residue replaced by one of the following monosaccharide residues: β- and α-2- deoxy-D-arabino-hexopyranosyl, α-D-mannopyranosyl, 2-O-methyl-β-D- glucopyranosyl, and 2-O-methyl-α-D-mannopyranosyl. 1-O-Hexadecyl-2-O- methyl-3-O-(2'-deoxy-β-D-arabino-hexopyranosyl)-sn-glycerol (2) was more effective than 1 in inhibiting the growth of MCF-7 (human breast cancer) and its adriamycin-resistant form MCF-7/adriamycin, and murine Lewis lung cancer cells. 2-Deoxy-β-D-arabino-hexopyranoside 2 was also an effective growth inhibitor of two drug-resistant leukemic cell lines, P388/Adr and L1210/vmdr.

Full text of DOI:10.1021/jm960164j

J . Med. Chem. 1996, 39, 3241-3247
3241
Articles
Syn th esis a n d Gr ow th In h ibitor y P r op er ties of Glycosid es of
1-O-Hexa d ecyl-2-O-m eth yl-sn -glycer ol, An a logs of th e An titu m or Eth er Lip id
ET-18-OCH3 (Ed elfosin e)
J ose´ R. Marino-Albernas,† Robert Bittman,*,† Andrew Peters,‡ and Eric Mayhew‡
Department of Chemistry and Biochemistry, Queens College of the City University of New York,
Flushing, New York 11367-1597, and The Liposome Company, Princeton, New J ersey 08540-6619
Received February 29, 1996X
Glycosylated antitumor ether lipids (GAELs), analogs of 1-O-octadecyl-2-O-methyl-sn-glycero-
3-phosphocholine (1, ET-18-OCH3, edelfosine), were synthesized in good overall yields by
glycosylation of 1-O-alkyl-2-O-methyl-sn-glycerol and tested for in vitro antineoplastic activity
against a variety of murine and human tumor cell lines. Stereospecific glycosylation was
achieved by the use of 2-O-acetyl-3,4,6-tri-O-benzylglucopyranosyl and -mannopyranosyl
trichloroacetimidates as donors, with trimethylsilyl trifluoromethanesulfonate as catalyst in
the presence of molecular sieves at -78 °C. The GAELs differ from 1 in having the sn-3-
phosphocholine residue replaced by one of the following monosaccharide residues: â- and R-2-
deoxy-D-arabino-hexopyranosyl, R-D-mannopyranosyl, 2-O-methyl-â-D-glucopyranosyl, and 2-O-
methyl-R-D-mannopyranosyl. 1-O-Hexadecyl-2-O-methyl-3-O-(2′-deoxy-â-D-arabino-hexopyran-
osyl)-sn-glycerol (2) was more effective than 1 in inhibiting the growth of MCF-7 (human breast
cancer) and its adriamycin-resistant form MCF-7/adriamycin, and murine Lewis lung cancer
cells. 2-Deoxy-â-D-arabino-hexopyranoside 2 was also an effective growth inhibitor of two drug-
resistant leukemic cell lines, P388/Adr and L1210/vmdr.
In tr od u ction
followed by functionalization of the C-2′ position of the
glycoside and deprotection. The present study also
compares the in vitro growth inhibitory activities of
these analogs against the following cells: A549 (human
lung carcinoma), MCF-7 (human breast carcinoma) and
its adriamycin-resistant form MCF-7/Adr, HT29 (human
colon carcinoma), Lewis lung (murine lung carcinoma),
P388 (murine leukemia) and its adriamycin-resistant
form P388/Adr, L1210 (murine leukemia) and its vmdr
form L1210/vmdr (transfected with a plasmid containing
mdr 1).
Edelfosine, 1-O-octadecyl-2-O-methyl-sn-glycero-3-
phosphocholine (1), also known as ET-18-OCH3, belongs
to a family of antitumor ether lipids (AELs) that have
been shown to specifically inhibit the growth of tumor
cells, inhibit tumor cell invasion and metastasis, and
enhance the tumoricidal capacity of macrophages (for
recent reviews see refs 1, 2). Many AELs have been
synthesized and analyzed for antitumor activity.1,2
Some glycosylated antitumor ether lipids (GAELs) have
been synthesized in which the 3-phosphocholine residue
of 1 has been substituted by O-R- and O-â-D-glucosyl,3
O-â-D-maltosyl,4,5 O-â-D-lactosyl,5 and S-R- and S-â-D-
glucosyl.3 The ET-16-OCH3-S-â-D-glucoside3 and ET-
16-OCH3-O-â-D-maltoside6 were not cytotoxic to leuke-
mic cells in vitro, whereas the other glycolipids displayed
cytotoxic activities against epithelial7 and mouse-
derived3 cancer cell lines that varied with cell type. In
this report we present the synthesis of five new GAEL
analogs of ET-16-OCH3 (Figure 1), in which the phos-
phocholine residue has been replaced by 2-deoxy-â-D-
arabino-hexopyranosyl (2) and 2-deoxy-R-D-arabino-
hexopyranosyl (3), and by 2-O-alkyl-monosaccharides
such as 2-O-methyl-â-D-glucopyranosyl (4) and 2-O-
methyl-R-D-mannopyranosyl residues (6); in addition,
R-D-mannopyranoside 5 was synthesized. These R- and
â-D-GAELs, which differ from each other at the 2
position of the glycosyl residue, were prepared via the
glycosylation of 1-O-hexadecyl-2-O-methyl-sn-glycerol
(7) with glycosyl trichloroacetimidate donors 8 and 9,
Resu lts a n d Discu ssion
I. Syn th etic Ch em istr y. The synthesis of 1-O-
hexadecyl-2-O-methyl-sn-glycerol (7) has been carried
out previously starting from D-mannitol4 and, although
this approach affords 7 in moderate yields, it requires
four laborious steps for the synthesis of the key inter-
mediate, 3-O-benzyl-sn-glycerol. A more direct syn-
thetic approach to 7 was reported8 in which the Lewis
acid-catalyzed (BF3‚Et2O) regioselective ring opening of
(R)-glycidyl arenesulfonates with 1-hexadecanol gives
1-O-hexadecyl-3-O-arenesulfonyl-sn-glycerol in moder-
ate to good yield and high enantiomeric excess; alter-
natively, the tert-butyldiphenylsilyl ether of glycidol can
be used as the precursor to 7.8 Whereas this procedure
led to 7 after 2-O-methylation and 3-O-deprotection, the
process is tedious to be scaled up. In the present work,
we synthesized 7 (Scheme 1) by using an efficient and
attractive method of synthesis of 3-O-protected-sn-
glycerol developed on a small scale in this laboratory.9,10
This procedure is based on asymmetric dihydroxyl-
ation11 of allyl 4-methoxyphenyl ether using AD-mix-R
in a mixture of 1:1 tert-butyl alcohol-water at 0 °C, to
† Queens College.
‡ The Liposome Co.
X Abstract published in Advance ACS Abstracts, August 1, 1996.
S0022-2623(96)00164-1 CCC: $12.00 © 1996 American Chemical Society

3242 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 17
Marino-Albernas et al.
F igu r e 1. Structures of ET-18-OCH3 (edelfosine, 1) and the new GAELs (2-6).
Sch em e 1.a Synthesis of 7 by Asymmetric
Sch em e 2.a Synthesis of Glycosyl Donors 8 and 9
Dihydroxylation
a
Reagents: (a) 100% AcOH; (b) H2NNH2‚AcOH, DMF; (c)
a
Reagents: (a) AD-mix-R, 1:1 tert-BuOH/H2O; (b) n-Bu2SnO/
CCl3CN, K2CO3, CH2Cl2; (d) 80% AcOH.
MeOH; (c) n-C16H33Br, CsF, DMF; (d) MeI, NaH, DMF; (e) CAN,
4:1 MeCN-H2O.
process can be scaled up to provide 20-30 g of 7 per
reaction. At this level, the products of regioselective
monoalkylation 11 and 12 can be separated readily by
crystallization from hexane-ethyl acetate in excellent
yields. Moreover, the ratio of 11/12 can be increased
by using a mixture of methanol and chloroform (1:10
v/v) instead of pure methanol as the solvent for the
O-stannylation of 10.
give 3-O-(4-methoxyphenyl)-sn-glycerol (10) in 90%
chemical yield and 95% ee. Recrystallization of the
purified 1,2-diol increased its enantiomeric excess. This
procedure was recently modified in order to minimize
the amounts of AD-mix-R employed for this reaction,
as illustrated by enantioselective syntheses of 7 and
O-benzyl-sn-glycerol.10 Selective monoalkylation of 10
in DMF with 1-bromohexadecane via 1,2-O-stannylidene
in the presence of cesium fluoride10,12 afforded a mixture
of monosubstituted glycerols, sn-1-O-hexadecyl (11), and
sn-2-O-hexadecyl (12), in 97% overall yield. The ratio
of 11/12 after chromatographic separation was 12:1.
Confirmation for structures 11 and 12 was obtained by
13C NMR spectroscopy. By INEPT experiments, the C-2
signal of the glycerol moiety was assigned; for 11, the
C-2 NMR signal appears at 69.53 ppm, whereas for 12
an expected downfield shift of the C-2 signal (78.69 ppm)
was observed. After chromatographic separation of
these two isomers, 11 was methylated (97%) by treat-
ment with MeI-NaH-DMF, giving 1,2-di-O-alkyl-3-O-
protected-sn-glycerol (13). Removal of the 3-O-(4-
methoxyphenyl) function with ammonium cerium(IV)
nitrate (CAN) in aqueous acetonitrile gave 7 in 95%
yield after column purification.
For the syntheses of glycoside analogs of 1, with a
2-deoxy, 2-O-alkyl, or 2-axial-hydroxy function on the
monosaccharide residue of the final product, the pro-
tecting groups of positions C-3, C-4, and C-6 of the
glycosyl donor must enable preferential deprotection of
the C-2 protecting group of the glycoside and also be
resistant to the conditions used for 2-O-alkylation (in
compounds 4 and 6) and for deoxygenation via radical
reduction of xanthates (in compounds 2 and 3). For this
purpose, a common synthon that suits both classes of
compounds was selected. The use of trichloroacet-
imidates such as 8 and 9 matched this requirement.13
1,2-trans-Glycosyl donors with these characteristics, and
an O-acetyl function at C-2 and O-benzyl functions at
C-3, C-4, and C-6, are readily available from their
respective benzylated 1,2-orthoesters (Scheme 2). For
the synthesis of 8, 1414 was acetolized in glacial acetic
acid15,16 to afford 1,2-trans-di-O-acetate 16. The 1-O-
acetate function was removed selectively by treatment
of 16 with hydrazine acetate in DMF,17 giving 18
quantitatively after aqueous workup. Hemiacetal 18
was treated with trichloroacetonitrile-potassium car-
bonate in dichloromethane to afford an R/â mixture of
trichloroacetimidate 8 in 85% yield after flash chroma-
tography. For the synthesis of 9, the benzylated 1,2-
The synthesis of 3-O-glyceryl acceptors via asym-
metric dihydroxylation of allyl 4-methoxyphenyl ether
(Scheme 1) is very simple, high yielding, and provides
products with high enantiomeric excess. This procedure
affords 7 in four steps and 74% overall yield, starting
from the readily available allyl 4-methoxyphenyl ether.
A practical advantage of this sequence is that this

Glycosylated Antitumor Ether Lipids
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 17 3243
Sch em e 3.a â-Glycosidation of Glycosyl Acceptor 7 by
TMSOTf-Catalyzed Reaction with Glucosyl Donor 8 and
Functionalization of the C-2′ Position
Sch em e 4.a R-Glycosidation of Glycosyl Acceptor 7 by
TMSOTf-Catalyzed Reaction with Mannosyl Donor 9
and Functionalization of the C-2′ Position
a
Reagents: (a) TMSOTf, CH2Cl2, mol sieves (3 Å), -78 °C, 10
min; (b) NH3, MeOH, rt, 15 min; (c) MeI, NaH, DMF; (d) H2, Pd-
C, 1:1 THF-AcOH; (e) CS2, NaH, imidazole, MeI; (f) Bu3SnH,
AIBN, toluene.
a
Reagents: (a) TMSOTf, CH2Cl2, mol sieves (3 Å), -78 °C, 10
min; (b) NH3, MeOH, rt, 15 min; (c) MeI, NaH, DMF; (d) H2, Pd-
C, 1:1 THF-AcOH; (e) CS2, NaH, imidazole, MeI; (f) Bu3SnH,
AIBN, toluene.
balloon pressure of hydrogen to afford the deblocked
GAELs 4 and 5 in 96% and 94% yields, respectively.
The 2′-deoxy function was introduced into 2 and 3 via
radical reduction of xanthates (Schemes 3 and 4), which
is a common procedure to deoxygenate carbinols.21,22
The 2′-alcohols 21 and 22 were converted into their
respective xanthates by treatment, in tetrahydrofuran,
with sodium hydride, carbon disulfide, and a catalytic
amount of imidazole followed by reaction with methyl
iodide (Scheme 3). Xanthates 25 and 26 were radical-
reduced with tributyltin hydride in the presence of R,R′-
azobis(isobutyronitrile) (AIBN) in toluene to yield the
protected 2′-deoxyglycosides 27 and 28 in yields of 92
and 94%, respectively. Similar yields have been re-
ported for the preparation of 2-deoxyglycosides by the
modified23 Barton-type deoxygenation of secondary al-
cohols, in which a 2-O-(pentafluorophenoxy)thiocarbonyl
intermediate is prepared.24 The 13C-NMR spectra of 27
and 28 showed an upfield shift of the C-2′ signal (36.68
and 35.42 ppm, respectively), which is characteristic of
â- and R-2-deoxy-arabino-hexopyranosides. The 1H-
NMR spectrum of 27 showed the â H-1 anomeric signal
at 4.46 ppm as a dd, and a ddd at 2.36 ppm, which was
orthoester 15, which was prepared in a route analogous
to that used to make 14,14 was hydrolyzed with 80%
acetic acid at room temperature for 6 h; treatment of
hemiacetal 17 with trichloroacetonitrile-potassium car-
bonate in dichloromethane gave 9 in high yield.
The use of 1,2-trans-di-O-acetyl derivatives in glyco-
sylation reactions promoted by trimethylsilyl trifluoro-
methanesulfonate (TMSOTf) affords 1,2-trans-glycosides
in high yields.18,19 However, when 7 was glucosylated
with 1,2-di-O-acetyl-3,4,6-tri-O-benzyl-â-D-glucopyran-
ose 16 in dichloromethane, using a ratio of donor:
acceptor:promoter of 1:1:1 at -20 °C, â-glycoside 19 was
obtained in only 55% yield, along with 10% of the
transesterification product of 7. On the other hand, as
shown in Scheme 3, glycosylation of 7 with 8 in
dichloromethane promoted by TMSOTf catalysis at -78
°C (donor:acceptor:promoter, 1.1:1:0.035) in the presence
of molecular sieves 3 Å proceeded in 10 min to give
exclusively 19 in 76% yield. Similarly, glycosylation of
7 by using the 2-O-acetylmannosyl donor 9, according
to the same TMSOTf catalytic method described for the
synthesis of 19, led to the R-D-mannopyranoside 20 in
87% yield, without detection of any transesterification
product (Scheme 4). Thus the stereochemistry of the
2′-O-acetyl group directs the outcome of the glycosida-
tion reaction of imidates 8 and 9 with glycosyl acceptor
7, independent of the composition of the anomeric
mixture of the glycosyl donor. This result is consistent
with recent reports of stereospecific glycosidation via
neighboring-group participation in 2-O-acetylglycosyl
trichloroacetimididates with TMSOTf as catalyst.13,20
The key feature of the next stage of this work was
the functionalization of the C-2′ position of these two
monosaccharides. The 2′-O-methyl group was intro-
duced into 4 and 5 as follows (Scheme 3). First, the 2′-
O-acetyl function of 19 and 20 was removed quantita-
tively by aminolysis using NH3/MeOH, and then the 2′-
hydroxy group was methylated by using MeI-NaH-
DMF, to give 23 and 24 in 97% and 98% yields,
respectively. The O-benzyl protecting groups were
removed in 1:1 TMF-HOAc using Pd-C under a
1
assigned to H-2′equatorial (H-2′e). The H-NMR spec-
trum of 28 showed signals at 4.97 ppm (dd with very
small coupling constants) and at 2.29 ppm (ddd), which
were assigned to H-1′a and H-2′e, respectively. In each
compound, the H-2′a signal was partially buried under
a CH2 triplet of the sn-1 O-n-alkyl chain between 1.4
and 1.8 ppm.
After careful purification of these â- and R-2-deoxy-
arabino-hexopyranosides by column chromatography on
silica gel, and elution with a gradient of polarity using
hexane-ethyl acetate, we removed the O-benzyl pro-
tecting groups in 1:1 THF-HOAc in the presence of
Pd-C and under a balloon pressure of hydrogen to give
2 and 3 in good yields after column purification.
Finally, monosaccharides 2-5 were filtered through
lipophilic Sephadex LH-20 using methanol to remove
low molecular weight impurities.
II. Biologica l Resu lts a n d Discu ssion . Table 1
presents the data for the in vitro biological evaluation
of the growth inhibitory properties of GAELs 2-6 and

3244 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 17
Marino-Albernas et al.
Ta ble 1. Growth Inhibitory Properties of ET-18-OCH3 (1) and GAELs 2-6a
GI50 (µM)
cell line
A549
MCF7
MCF7/Adr
HT29
Lewis lung
P388
P388/Adr
L1210
1
2
3
4
5
6
5.05 ( 0.80b
9.66 ( 2.50b
30.35 ( 5.07b
2.20 ( 0.27c
30.24 ( 6.32d
4.33 ( 1.37e
6.39 ( 2.43e
3.32 ( 1.68d
10.99 ( 6.36d
9.90 ( 0.99
6.93 ( 0.12
12.85 ( 0.85
7.59 ( 0.23
11.05 ( 0.49
12.65 ( 0.78
10.25 ( 2.34
7.02 ( 0.49
7.09 ( 0.33
19.65 ( 0.07
24.45 ( 0.64
24.40 ( 0.42
29.60 ( 0.28
18.30 ( 0.14
23.05 ( 0.64
21.75 ( 0.63
15.55 ( 0.07
18.20 ( 0.00
18.55 ( 0.07
20.00 ( 0.28
18.10 ( 0.14
21.70 ( 0.57
23.30 ( 0.71
23.20 ( 0.85
26.00 ( 0.71
18.10 ( 1.13
29.30 ( 5.66
18.75 ( 0.49
26.95 ( 1.06
15.45 ( 0.35
16.50 ( 1.13
16.20 ( 0.99
18.90 ( 0.00
L1210/vmdr
a
Cells were treated with varying concentrations of drugs for 72 h. Details of the in vitro assay are described in the Experimental
Section. GI50 values are the mean (SD. The GI50 value from each experiment “n” was generated from three individual wells on two
b
d
separate plates (six total wells); n ) 1 for compounds 3-6; n ) 2 for most cell lines treated with compound 2. n ) 3. c n ) 2. n ) 6.e n
) 8.
of edelfosine (1) on mouse and human tumor cells. The
GI50 values (drug concentrations required to inhibit
growth by 50%) indicate that 2′-deoxy-â-D-arabino-
hexopyranoside 2 was more potent against every cell
tested than its 2-O-methyl-2′-deoxy-â-D-arabino-hexo-
pyranoside homolog 4. The R anomers 3, 5, and 6 were
less effective than 2 in inhibiting growth of the cell lines
shown in Table 1. Compound 2 maintained high
potency against the murine leukemia cell line L1210/
vmdr, and against the drug-resistant tumor cell lines
we investigated (MCF-7/Adr and P388/Adr). Compound
2 was highly effective against drug-sensitive MCF-7
(human breast cancer) cells, and was appreciably more
effective than edelfosine (1) against mouse Lewis lung
cells and the multidrug resistant human MCF7/Adr cell
line. However, 1 had higher growth inhibitory activity
than GAELs 2-6 against mouse leukemia P388 cells
and P3888/adriamycin-resistant cells.
Exp er im en ta l Section
Gen er a l Meth od s. The solvents used were dried and then
distilled under a positive pressure of nitrogen as follows:
dichloromethane was refluxed over calcium hydride and
distilled before use; tetrahydrofuran (THF) was refluxed over
sodium benzophenone ketyl and distilled before use; methanol
was refluxed over Mg(OMe)2 and distilled before use; toluene
was distilled and then redistilled from calcium hydride before
use. TMSOTf, CAN, cesium fluoride, dibutyltin oxide, 1-bro-
mohexadecane, methyl iodide, tributyltin hydride, and AIBN
were purchased from Aldrich. Anhydrous N,N-dimethyl-
formamide (DMF), acquired from J anssen Chimica, was used
without purification. Optical rotations were measured at 20
°C with a J ASCO DIP-140 digital polarimeter in a cell of 1-dm
pathlength; 1% solutions in chloroform were used unless
otherwise stated. 1H-NMR spectra were recorded with IBM-
Bruker WP 200 and AMX-400 Bruker spectrometers at 200
and 400.13 MHz, respectively, for solutions in CDCl3 (internal
reference of Me4Si). 13C-NMR spectra were recorded with
IBM-Bruker WP 200 and AMX-400 Bruker spectrometers at
75 and 100.57 MHz, respectively, and the 13C chemical shifts
are given by assigning 77.0 ppm for the central line of CDCl3.
Reactions were monitored using TLC aluminum plates of silica
gel 60 F254 (EM Separations), and the spots were visualized
by charring with 10% sulfuric acid in ethanol and/or short
wavelength UV light. Column chromatography was carried
out on silica gel 60 (230-400 mesh, purchased from Aldrich)
isocratically unless otherwise stated, using a peristaltic pump.
Solid synthons were dried under vacuum (0.02 mmHg), and
all reactions were carried out under dry nitrogen using air-
sensitive glassware (greaseless vacuum/gas manifold). Nitro-
These biological results indicate that the deoxygluco-
pyranosyl analogs of 1 may be good candidates for
further studies as new antitumor ether lipids, especially
with regard to their activities against multidrug resis-
tant cells. Although the use of glycosyl donors such as
8 and 9 led to 2′-deoxyglycosides in good overall yields
(â-glycoside 2 in 36% yield; R-glycoside 3 in 55% yield
in 11 steps starting from 10 and the corresponding
benzylated orthoesters), this process involves a consid-
erable number of steps that would be time consuming
to scale up. More efficient routes to 2 and 3, as well as
new analogs of the GAELs family, need to be evaluated
in future studies.
gen gas was dried through
a drying tower of granular
anhydrous calcium chloride. Molecular sieves (3 Å) were dried
at 150 °C under vacuum over P2O5 for 12 h and stored under
vacuum over P2O5.
1-O-Hexa d ecyl-3-O-(4-m eth oxyp h en yl)-sn -glycer ol (11)
a n d 2-O-h exa d ecyl-3-O-(4-m et h oxyp h en yl)-sn -glycer ol
(12). A mixture of 3-O-(4-methoxyphenyl)-sn-glycerol (10,
0.737 g, 3.7 mmol), di-n-butyltin oxide (1.11 g, 4.46 mmol) in
dry methanol (10 mL) was refluxed with stirring until the
oxide was dissolved. The solvent was evaporated, and the solid
was dried under vacuum for 3 h and then dissolved in DMF
(30 mL). Cesium fluoride (1.5 g) and 1-bromohexadecane (1.57
mL, 5.13 mmol) were added. The mixture was stirred at room
temperature until TLC (4:1 hexane-ethyl acetate) indicated
that the reaction was complete. Ethyl acetate (20 mL) and
water (0.5 mL) were added, and the mixture was stirred for
30 min. A white solid (dibutyltin oxide) was filtered, and the
solvent was evaporated to give a crude mixture of 11 and 12.
The mixture of monoalkylated products was separated by
column chromatography to afford 11 and 12. Compound 11:
1.42 g (90% yield). 1H-NMR: δ 6.84-6.78 (m, 4H, Ph), 4.13
(m, 1H, H-2), 4.03-3.95 (m, 2H, H-3a, H-3b), 3.76 (s, 3H,
OCH3), 3.57 and 3.54 (dd, 2H, J 1a,1b ) 12.0 Hz, J 1,2 ) 4.0 Hz,
H-1a, H-1b), 3.46 (t, 2H, J ) 4.0 Hz, OCH2), 2.56 (1H, OH),
1.60 (t, 2H, J ) 6.0 Hz, CH2), 1.25 (s, 26H, CH2), 0.88 (t, 3H,
J ) 6.0 Hz, CH3). 13C-NMR: δ 115.89, 114.99 (Ar), 72.02
Con clu sion
New glycosylated antimor ether lipids (GAELs) were
synthesized by glycosylation of 1-O-hexadecyl-2-O-
methyl-sn-glycerol (7), which was prepared from 3-O-
(4-methoxyphenyl)-sn-glycerol (10) and analyzed for in
vitro antitumor activity. 1-O-Hexadecyl-2-O-methyl-3-
O-(2′-deoxy-â-D-arabino-hexopyranosyl)-sn-glycerol (2)
was found to possess higher antitumor activity than its
2′-O-methyl-2′-deoxy-â-D-arabino-hexopyranoside ana-
log 4 against a variety of murine and human tumor cell
lines. Three R-glycosyl diglycerides (2′-deoxy-R-D-ara-
bino-hexopyranoside 3, R-D-mannopyranoside 6, and
2-O-methyl-R-D-mannopyranoside 5) had similar activi-
ties to 4 for all of the cell lines tested. The 2′-deoxy-â-
D-arabino-hexopyranoside 2 was more effective than the
prototypic AEL ET-18-OCH3 (edelfosine, 1) against
MCF-7, MCF-7/Adr, Lewis lung, and L1210/vmdr cells.

Glycosylated Antitumor Ether Lipids
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 17 3245
(OCH2), 71.97 (C-1), 70.16 (C-3), 69.53 (C-2), 56.02 (OCH3).
Compound 12: 0.12 g (7.6% yield). 1H-NMR: δ 6.87-6.80 (m,
4H, Ph), 3.89 (d, 2H, J ) 4.4 Hz), 3.73-3.48 (m, 5H, H-1a,
H-1b, H-2, H-3a, H-3b), 3.63 (s, OCH3), 2.25 (1H, OH), 1.60 (t,
2H, J ) 6.0 Hz, CH2), 1.25 (s, 26H, CH2), 0.88 (t, 3H, J ) 6.0
Hz, CH3). 13C-NMR: δ 115.93, 114.99 (Ar), 78.69 (C-2), 62.75
(C-1), 56.03 (OCH3).
Gen er a l P r oced u r e for Meth yla tion of Alcoh ols. To a
stirred solution of the alcohols (1 mmol) in dry DMF (5 mL)
was added sodium hydride (2.5 mmol) portionwise at 0 °C.
After the mixture was stirred for 30 min, methyl iodide (2.5
mmol) was added. The reaction was stirred at room temper-
ature. Once the reaction was complete, methanol was added
at 0 °C to destroy the excess of sodium hydride. The solvent
was evaporated under vacuum, and the residue was dissolved
in ethyl acetate. The organic solution was washed with water
and brine, dried (Na2SO4), filtered, and evaporated. This
reaction afforded pure products; therefore, chromatographic
purification was not necessary except for characterization
purposes.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(4-m eth oxyp h en yl)-sn -
glycer ol (13). Compound 11 (1.2 g, 2.84 mmol) was meth-
ylated as described above to give 13 as a white solid (1.2 g) in
97% yield after column purification; [R]D -6.9°; 13C-NMR: δ
115.90, 114.99 (Ar), 78.8 (C-2), 72.02, 71.98, 70.20 (C-1, C-3,
OCH2), 57.88, 56.02 (OCH3).
1-O-Hexa d ecyl-2-O-m eth yl-sn -glycer ol (7). To a solution
of 13 (1.0 g, 2.3 mmol) in 4:1 acetonitrile-water (21 mL) was
slowly added ammonium cerium(IV) nitrate (2.9 g, 5.5 mmol)
at 0 °C with vigorous stirring. The mixture was stirred at
room temperature for 1 h. After this time TLC (4:1 hexanes-
ethyl acetate) showed complete conversion of 13 into the title
compound. The reaction was quenched by the addition of
sodium sulfite (1.0 g). The mixture was diluted with ethyl
acetate, and the organic solution was washed with water and
brine, dried (Na2SO4), filtered, and evaporated. The residue
was purified by column chromatography (6:1 hexane-ethyl
acetate) to give 7 (0.853 g, 94%) as a low-melting white solid;
[R]D -9.5°; lit.10 [R]D -10.13° (c 1.5, CHCl3), lit.25 [R]D -9.92°
(c 1.64, CHCl3), lit.8 [R]D -9.46° (c 1.64, CHCl3).
2-O-Ace t yl-3,4,6-t r i-O-b e n zyl-r,â-D-glu cop yr a n osyl
Tr ich lor oa cetim id a te (8). To a solution of 1,2-di-O-acetyl-
3,4,6-tri-O-benzyl-â-D-glucopyranose16 (16, 1.0 g, 1.87 mmol)
in dry DMF (10 mL) was added hydrazine acetate (0.213 g,
2.32 mmol). The mixture was stirred under nitrogen for 4 h.
After this time TLC (4:1 hexane-ethyl acetate) showed that
the reaction was complete. The mixture was diluted with ethyl
acetate and washed with water and brine. The organic layer
was dried (Na2SO4), filtered, and evaporated to give 18
quantitatively (0.921 g). The crude hemiacetal 18 was pure
enough to continue with this procedure. Compound 18 was
dried under vacuum for 4 h and then dissolved in dry
dichloromethane (30 mL). Trichloroacetonitrile (0.231 mL)
and anhydrous potassium carbonate (1.22 g) were added. The
mixture was stirred for 3 h under nitrogen. TLC (4:1 hexane-
ethyl acetate) showed traces of 18 and the faster-running title
compound. The reaction was quenched by filtration of the
inorganic base through a pad of Celite 545, and the solvent
was evaporated. Crude 8 was then purified through a short
column using 8:1 hexanes-ethyl acetate to give the glucosyl
donor 8 in 85% yield. 1H-NMR: δ 8.63 (s, 0.46H, NH), 8.56
(s, 0.56H, NH), 7.32-7.15 (m, 15H, 3Ph), 6.52 (d, 0.53H, J 1,2
) 3.5 Hz, H-1a), 5.74 (d, 0.46H, J 1,2 ) 8.0 Hz, H-1b), 5.29 (dd,
0.46H, J 2,3 ) 9.4 Hz, H-2b isomer), 5.09 (dd, 0.53H, J 2,3 ) 10.0
Hz, H-2a isomer), 1.99 (s, CH3CO).
2-O-Acet yl-3,4,6-t r i-O-b en zyl-r,â-D-m a n n op yr a n osyl
Tr ich lor oa cetim id a te (9). Benzylated 1,2-orthoester 15 (3.0
g) was hydrolyzed in 80% HOAc (50 mL) at room temperature
for 6 h. After this time, TLC (2:1 hexanes-ethyl acetate)
showed complete conversion of 15 into a slower-moving mate-
rial. Acetic acid was coevaporated under vacuum with toluene
to afford pure 17 quantitatively (3.0 g). Hemiacetal 17 was
dried under vacuum overnight. Compound 17 was treated
with trichloroacetonitrile-potassium carbonate as described
for 8 to give the mannosyl donor 9 in 96% yield (3.8 g). 1H-
NMR: δ 8.71 (s, NH), 8.63 (s, NH), 7.35-6.78 (m, 15H, 3Ph),
6.29 (d, H-1â), 5.89 (d, H-1R), 5.49 (dd, H-2), 4.89-4.47 (m),
4.06-3.68 (m), 2.18 (s, 3H, CH3).
Gen er a l P r oced u r e for Glycosyla tion of 7 w ith 1,2-
tr a n s-Glycosyl Don or s 8 a n d 9. A mixture of the glycosyl
donor 8 or 9 (1.4 mmol) and the glycosyl acceptor 7 (1.3 mmol)
in anhydrous dichloromethane (30 mL) was stirred under dry
nitrogen with molecular sieves (3 Å) for 20 min at room
temperature. The mixture was cooled at -78 °C, and TMSOTf
(50 µmol, 0.035 equiv) was added. Every reaction was
complete in 10 min. The Lewis acid was neutralized at room
temperature with triethylamine (20 µL). The solvent was
evaporated and the crude 1,2-trans-glycopyranosides were
purified by column chromatography.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(2′-O-a cetyl-3′,4′,6′-tr i-
O-ben zyl-â-D-glu copyr a n osyl)-sn -glycer ol (19). Compound
7 (433.3 mg, 1.3 mmol) was glucosylated with 8 (930 mg, 1.4
1
mmol) to give 19 in 76% yield (805 mg); [R]D -8.5°; H-NMR:
δ 7.32-7.15 (m, 15H, 3PhCH2), 4.99 (dd, 1H, J 1′,2′ ) 7.9 Hz,
J 2′,3′ ) 8.4 Hz, H-2′), 4.78 and 4.66 (2d, 2H, J ) 11 Hz, CH2Ph),
4.78 and 4.54 (2d, 2H, J ) 12 Hz, CH2Ph), 4.63 and 4.54 (2d,
2H, J ) 12 Hz, CH2Ph), 4.49 (d, 1H, H-1′), 3.92-3.35 (12H),
3.41 (s, CH3O), 1.95 (s, 3H, CH3CO), 1.59 (m, 4H, 2CH2), 1.25
(s, 26H, CH2), 0.87 (t, 3H, J ) 6 Hz, CH3). 13C-NMR: δ 169.6
(CO), 138.27, 128.41, 127.98, 127.80 (Ph), 101.39 (C-1′), 57.9
(CH3O), 20.85 (CH3CO), 14.06 (CH3).
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(2′-O-a cetyl-3′,4′,6′-tr i-
O-ben zyl-r-D-m a n n op yr a n osyl)-sn -glycer ol (20). Com-
pound 7 (0.871 g, 2.6 mmol) was glycosylated with 9 (1.90 mg,
2.9 mmol) to give the title compound in 87% yield (1.83 g);
[R]D +37.5°; 1H-NMR: δ 7.33-7.12 (m, 15H, 3PhCH2), 5.37
(dd, 1H, J 2′,3′ ) 2.7 Hz, H-2′), 4.86 (d, 1H, J 1′,2′ ) 1.6 Hz, H-1′),
4.86 and 4.49 (2d, 2H, J ) 11 Hz, CH2Ph), 4.70 and 4.54 (2d,
2H, J ) 11 Hz, CH2Ph), 4.69 and 4.50 (2d, 2H, J ) 12 Hz,
CH2Ph), 2.14 (s, 3H, CH3CO), 1.54 (t, 2H, J ) 6.0 Hz), 1.25 (s,
26H), 0.87 (t, 3H). 13C-NMR: δ 170.39 (CO), 138.50, 132.29,
128.28, 127.55 (Ph), 98.17 (C-1′), 58.07 (CH3O), 31.90, 29.51,
26.10, 21.07 (CH2), 14.07 (CH3).
Gen er a l P r oced u r e for Dea cetyla tion . Compounds 19
and 20 were deacetylated at room temperature with dry
ammonia gas dissolved in dry methanol in 15 min, giving 21
and 22, respectively. This reaction is quantitative and gives
very pure products. Methanol was evaporated, and the
alcohols were dried under vacuum and used in the next step.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(3′,4′,6′-tr i-O-ben zyl-2′-
O-m et h yl-â-D-glu cop yr a n osyl)-sn -glycer ol (23). Com-
pound 21 (149 mg) was 2′-O-methylated as described above
in 97% yield (145 mg); [R]D -9.7° (c 1.2, CHCl3); 13C-NMR: δ
138.89, 138.34, 128.34, 127.93, 127.71, 127.55 (Ph), 103.88 (C-
1′), 60.45, 57.88 (CH3O), 31.95, 29.69, 29.52, 29.35, 26.16, 22.68
(CH2), 14.06 (CH3).
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(3′,4′,6′-tr i-O-ben zyl-2′-
O-m eth yl-r-D-m a n n op yr a n osyl)-sn -glycer ol (24). Com-
pound 22 (39.6 mg) was methylated in 98% yield (39 mg); [R]D
+38.3°; 13C-NMR: δ 138.89, 138.34, 128.34, 127.93, 127.71,
127.55 (Ph), 98.5 (C-1′), 59.99, 57.80 (CH3O), 31.95, 29.69,
29.52, 29.35, 26.16, 22.68 (CH2), 14.06 (CH3).
Gen er a l P r oced u r e for Syn th esis of Xa n th a tes 25 a n d
26. Sodium hydride (15 mg, 0.62 mmol) was added to an ice-
cold solution of the alcohol (150 mg, 0.32 mmol) and imidazole
(4 mg, 0.055 mmol) in dry THF (5 mL). The mixture was
stirred for 1 h at room temperature under dry nitrogen, and
carbon disulfide (0.32 mmol) was added. Stirring was contin-
ued for 20 min, and methyl iodide (2.5 mmol) was added. The
reaction was monitored by TLC (3:1 hexanes-ethyl acetate).
Complete conversion of the respective alcohol into xanthate
25 or 26 was observed in each reaction. Methanol was added
at 0 °C to destroy the excess of sodium hydride. The solvent
was evaporated and the residue was dissolved in ether. The
organic solution was washed with water, dilute hydrochloric
acid, and water, dried (Na2SO4), and evaporated. These
compounds were used in the next step without further
characterization.
Gen er a l P r oced u r e for Ra d ica l Red u ction of Xa n -
th a tes. A solution of â-glycoside 25 (precursor to 2) or
R-glycoside 26 (precursor to 3) (100 mg, 0.117 mmol) in dry
toluene (4 mL) was added dropwise to a refluxing solution of

3246 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 17
Marino-Albernas et al.
tri-n-butyltin hydride (0.31 mL, 1.17 mmol) in dry toluene (2
mL) containing 5 mg of AIBN. The reaction was monitored
by TLC (4:1 hexanes-ethyl acetate); when it was complete,
the solvent was evaporated and the residue was purified by
column chromatography, eluting the column with hexanes first
and then with 20:1 hexanes-ethyl acetate, 15:1 hexanes-ethyl
acetate, and 10:1 hexanes-ethyl acetate to collect the pure
deoxygenated compound 27 or 28.
60.10, 58.10 (OCH3), 31.90, 29.64, 29.48, 29.31, 26.06, 22.67
(CH2), 14.06 (CH3). FAB HRMS: Calcd for C27H54O8Na,
529.3716; found 529.3702. Calcd for C27H55O8 (MH)+, 507.3897;
found 507.3902.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(r-D-m a n n op yr a n osyl)-
sn -glycer ol (6). Compound 22 (40 mg) was debenzylated to
give the title compound as a white amorphous solid in 95%
yield (25 mg); [R} +57.2°; 1H-NMR: δ 4.93 (d, 1H, J 1′,2′ ) 1.8
D
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(3′,4′,6′-tr i-O-ben zyl-2′-
deoxy-â-D-a r a bin o-h exopyr an osyl)-sn -glycer ol (27). Yield,
80 mg (92%); [R]D -7.1°; 1H-NMR: δ 7.32-7.18 (m, 15H,
3PhCH2), 4.89 (d, 1H, J ) 11.0 Hz, OCH2Ph), 4.68 (d, 1H, J )
11.0 Hz, OCH2Ph), 4.63 (d, 2H, J ) 11.0 Hz, OCH2Ph), 4.54
(d, 2H, J ) 11.0 Hz, OCH2Ph), 4.46 (dd, 1H, J 1′,2e′ ) 2.0 Hz,
J 1′,2a′ ) 9.5 Hz, H-1′), 3.97 (m, 1H, H-5′), 3.73-3.26 (m, 9H),
3.44 (s, OCH3), 2.36 (ddd, 1H, J 2e′,3′ ) 5.0 Hz, J 2′e,2′a ) 12.0
Hz, H-2′e), 1.73-1.43 (m, 5H), 1.25 (s, 26H, CH2), 0.87 (t, 3H,
CH3). 13C-NMR: δ 138.46, 128.41, 128.32, 127.97, 127.68,
127.51 (Ph), 100.20 (C-1′), 57.93 (OCH3), 36.68 (C-2′), 31.94,
29.68, 29.52, 29.35, 26.14, 22.67, 14.06.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(3′,4′,6′-tr i-O-ben zyl-2′-
deoxy-r-D-a r a bin o-h exopyr an osyl)-sn -glycer ol (28). Yield,
82 mg (94%); [R]D +25.5°; 1H-NMR: δ 7.32-7.15 (m, 15H,
3PhCH2), 4.97 (dd, 1H, H-1′), 4.89 and 4.52 (d, 2H, J ) 11.0
Hz, OCH2Ph), 4.66 and 4.50 (d, 2H, J ) 12.0 Hz, OCH2Ph),
4.68 and 4.62 (d, 2H, J ) 12.0 Hz, OCH2Ph), 3.98 (m, 1H, H-5′),
1.25 (s, 26H, CH2), 0.87 (t, 3H, CH3). 13C-NMR: δ 138.70,
138.59, 138.16, 128.28, 127.58, 97.82 (C-1′), 58.02 (OCH3),
35.45 (C-2′), 31.90, 29.64, 29.48, 29.31, 26.08, 22.64 (CH2),
14.06 (CH3).
Hz, H-1), 4.10 (m, 1H, H-5′), 1.25 (s, 26H, CH2), 0.87 (t, 3H,
CH3). FAB HRMS: Calcd for C27H54O8Na, 529.3716; found
529.3724.
Cell Cu ltu r e. A549, MCF-7, MCF-7/Adr, HT-29, L1210,
Lewis lung, P388, and P388/Adr cell lines were obtained from
the DCT Tumor Repository, NCI-Frederick Cancer Research
Facility (Frederick, MD). L1210 and L1210/vmdr cells, a
murine leukemia cell line transfected with the human mdr 1
gene (pHa MDR1/A), were a generous gift from Dr. Alan C.
Sartorelli, Yale University School of Medicine. Cells were
cultured in RMPI 1640 (Mediatech) medium supplemented
with 10% FBS (Life Technologies). The medium for L1210/
vmdr cells contained 0.06 µg/mL colchicine, which was re-
moved one week before the experiments were carried out.
Assa y of Gr ow th In h ibition . Cell growth was estimated
by in situ fixation of cells, followed by staining with the
protein-binding dye sulforhodamine B as described else-
where.26 Mouse and human tumor cells were treated with the
drugs for 72 h. Stock solutions of the drugs were made in
ethanol. The final concentration of ethanol did not exceed 1%.
Compound 1 was obtained from Calbiochem.
Gen er a l P r oced u r e To Rem ove Ben zyl Gr ou p s. Pro-
tected glycosides were dissolved in 1:1 THF-HOAc, and 1-2
equiv (by weight) of palladium on charcoal were added. The
mixture was degassed under vacuum, and then hydrogen was
let into the reactor. After this process was done three times,
the mixture was stirred at room temperature under a balloon
pressure of hydrogen. The reaction was usually complete in
4-5 h (TLC, 10:1:0.2 ethyl acetate-methanol-water). The
catalyst was filtered through a pad of Celite 545 and washed
with a large volume of solvent (1:1 THF-HOAc). The solvents
were evaporated under vacuum, and traces of HOAc were
coevaporated with distilled toluene. The deprotected glyco-
sides 2-6 were purified by column chromatography using a
mixture of distilled solvents (10:1 ethyl acetate-methanol).
The purified glycosides were then filtered in distilled methanol
through lipophilic Sephadex LH-20 to remove low molecular
weight impurities such as salts.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(2′-d eoxy-â-D-a r a bin o-
h exop yr a n osyl)-sn -glycer ol (2). Compound 27 (30 mg) was
debenzylated to give the title compound in 96% yield (14 mg);
[R]D -14.7°; 13C-NMR: δ 100.3 (C-1′), 78.7 (C-5′), 62.05 (C-6),
58.0 (OCH3), 38.5 (C-2′), 31.95, 29.69, 29.35, 26.11, 22.62 (CH2),
14.09 (CH3). FAB HRMS: Calcd for C26H52O7Na, 499.3611;
found 499.3601.
Ack n ow led gm en t. The FAB mass spectra were
recorded at the Michigan State University Mass Spec-
trometry Facility, which is supported in part by NIH
Grant DRR-00480.
Refer en ces
(1) Lohmeyer, M.; Bittman, R. Antitumor Ether Lipids and Alkyl-
phosphocholines. Drugs Future 1994, 19, 1021-1037.
(2) Houlihan, W. J .; Lohmeyer, M.; Workman, P.; Cheon, S. H.
Phospholipid Antitumor Agents. Med. Res. Rev. 1995, 15, 157-
223.
(3) Guivisdalsky, P. N.; Bittman, R.; Smith, Z.; Blank, M. L.; Snyder,
F.; Howard, S.; Salari, H. Synthesis and Antineoplastic Proper-
ties of Ether-linked Thioglycolipids. J . Med. Chem. 1990, 33,
2614-2621.
(4) Bauer, F.; Ruess, K.-P.; Liefla¨nder, M. Zur Stereoselektiven
Synthese von 1-O-Alkyl-3-O-benzyl-sn-glycerolen und 1-O-Alkyl-
2-O-methyl-3-O-â-D-glycosyl-sn-glycerolen. (Stereoselective syn-
thesis of 1-O-alkyl-3-O-benzyl-sn-glycerols and 1-O-alkyl-2-O-
methyl-3-O-â-D-glycosyl-sn-glycerols.) Liebigs Ann. Chem. 1991,
765-768.
(5) Erukulla, R. K.; Bittman, R. A Facile Stereoselective Synthesis
of Ether-linked â-D-Maltosyl- and â-D-Lactosyl-glycerolipids via
Peracetylated Disaccharide R-Phosphoramidates. Synth. Com-
mun. 1994, 24, 2765-2770.
(6) J ackson, J . K.; Burt, H.; Mok, W.; Salari, H.; Kumar, E. R.; Byun,
H.-S.; Bittman, R. A Comparison of the Lytic Properties of Two
Ether-linked Lipids, One with and One without Antineoplastic
Activity. Biochem. Cell Biol. 1994, 72, 297-303.
(7) Lu, X.; Rengan, K.; Bittman, R.; Arthur, G. The R and â Anomers
of 1-O-Hexadecyl-2-O-methyl-3-S-thioglucosyl-sn-glycerol Inhibit
the Proliferation of Epithelial Cancer Cell Lines. Oncol. Rep.
1994, 1, 933-936.
(8) Guivisdalsky, P. N.; Bittman, R. Regiospecific Opening of
Glycidyl Derivatives Mediated by Boron Trifluoride. Asym-
metric Synthesis of Ether-Linked Phospholipids. J . Org. Chem.
1989, 54, 4637-4642.
(9) Vilche`ze, C.; Bittman, R. An Efficient Asymmetric Synthesis of
Diacylglycerols. J . Lipid Res. 1994, 35, 734-738.
(10) Byun, H.-S.; Kumar, E. R.; Bittman, R. Enantioselective Syn-
theses of 1-O-Benzyl-sn-glycerol and 1-O-Hexadecyl-2-O-methyl-
sn-glycerol via Asymmetric Dihydroxylation of Allyl 4-Methoxy-
phenyl Ether. Use of AD-Mix Supplemented with Potassium
Persulfate. J . Org. Chem. 1994, 59, 2630-2633.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(2′-d eoxy-r-D-a r a bin o-
h exop yr a n osyl)-sn -glycer ol (3). Debenzylation of 2′-deoxy-
R-glycoside 28 (35 mg) gave 3 (21 mg) in 94% yield; [R]D +45.0°;
1H-NMR: δ 4.90 (dd, 1H, J 1′,2a′ ) 2.5 Hz, J 1′,2e′ ∼1.0 Hz, H-1′),
3.93 (m, 1H, H-5′), 3.44 (s, 3H, OCH3), 2.15 (ddd, 1H, J 2e′,3′
)
4.7 Hz, J 2e′,2a′ ) 11.5 Hz, H-2e′), 1.70 (ddd, 1H, H-2a′), 1.25 (s,
26H, CH2), 0.87 (t, 3H, CH3). 13C-NMR: δ 98.05 (C-1′), 79.33
(C-5′), 62.07 (C-6′), 57.94 (OCH3), 37.36 (C-2′), 31.90, 29.64,
29.48, 29.31, 26.06, 22.67 (CH2), 14.06 (CH3). FAB HRMS:
Calcd for C26H52O7Na, 499.3611; found 499.3600.
1-O-H exa d ecyl-2-O-m et h yl-3-O-(2′-O-m et h yl-â-D-glu -
cop yr a n osyl)-sn -glycer ol (4). Compound 23 (142.1 mg) was
debenzylated in 96% yield (89 mg) to give 4 as a white
amorphous solid; [R]D -14.7°; 13C-NMR: δ 103.64 (C-1′), 62.36
(C-6′), 60.61, 57.89 (OCH3), 31.90, 29.64, 29.48, 29.31, 26.06,
22.67 (CH2), 14.06 (CH3). FAB HRMS: Calcd for C27H54O8-
Na, 529.3716; found 529.3717. Calcd for C27H53O8 (M - H)+,
505.3740; found 505.3743.
1-O-Hexa d ecyl-2-O-m eth yl-3-O-(2′-O-m eth yl-r-D-m a n -
n op yr a n osyl)-sn -glycer ol (5). Compound 24 (39 mg) was
debenzylated to afford a white amorphous solid (25 mg, 94%);
[R]D +40.0°; 13C-NMR: δ 98.89 (C-1′), 79.5 (C-5′), 62.13 (C-6′),
(11) Kolb, H. C.; VanNieuwenhze, M. S.; Sharpless, K. B. Catalytic
Asymmetric Dihydroxylation. Chem. Rev. 1994, 94, 2483-2547.
(12) Nagashima, N.; Ohno, M. An Efficient O-Monoalkylation of
Dimethyl L-Tartrate via O-Stannylene Acetal with Alkyl Halides
in the Presence of Cesium Fluoride. Chem. Lett. 1987, 141-
144.

Glycosylated Antitumor Ether Lipids
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 17 3247
(13) Schmidt, R. R.; Kinzy, N. Anomeric-oxygen Activation for
Glycoside Synthesis: The Trichloroacetimidate Method. In
Advances in Carbohydrate Chemistry and Biochemistry; Horton,
D., Ed.; Academic Press: San Diego, 1994; Vol. 50, pp 21-123.
(14) Bore´n, H. B.; Ekborg, G.; Eklind, K.; Garegg, P. J .; Pilotti, A.;
Swahn, C.-G. Benzylated Orthoesters in Glycoside Synthesis.
Acta Chem. Scand. 1973, 27, 2639-2644.
(15) Lemieux, R. U.; Cipera, J . D. Preparation and Properties of R-D-
Glucopyranose 1,2-(ethyl orthoacetate) triacetate. Can. J . Chem.
1956, 34, 906-910.
(16) Trumtel, M.; Tavecchia, P.; Veyrie`res, A.; Sinay, P. The Synthesis
of 2′-Deoxy-â-disaccharides: Novel Approaches. Carbohydr. Res.
1989, 191, 29-52.
(17) Excoffier, G.; Gagnaire, D.; Utille, J .-P. Coupere Se´lective par
l’hydrazine des Groupements Ace´tyles Anome`res de Re´sidus
Glycosyles Ace´tyle´s. (Selective cleavage by hydrazine of the
anomeric acetyl groups of acetylated glycosyl residues.) Car-
bohydr. Res. 1975, 39, 368-373.
(18) Paulsen, H.; Paal, M. Lewissa¨ure-Katalysierte Syntheses von
Di- und Tri-Saccharid-Sequenzen der O- und N-Glycoproteine.
Anwendung von Trimethylsilyltrifuoromethanesulfonat. (Lewis
acid-catalyzed syntheses of di- and trisaccharide sequences of
O- and N-glycoproteins. Use of trimethylsilyltrifluoro-
methanesulfonates.) Carbohydr. Res. 1984, 135, 53-69.
(19) Ogawa, T.; Beppu, K.; Nakabayashi, S. Trimethylsilyl Trifluoro-
methanesulfonate as an Effective Catalyst for Glycoside Syn-
thesis. Carbohydr. Res. 1981, 93, C6-C9.
(20) Paulsen, H.; Reck, F.; Brockhausen, I. Synthese von modifi-
zierten Oligosacchariden der N-Glycoproteine ab Substrate fu¨r
N-Acetylglucosaminyltransferase I. (Synthesis of modified oli-
gosaccharides of N-glycoproteins as substrates for N-acetyl-
glucosaminyltransferase I.) Carbohydr. Res. 1992, 236, 39-71.
(21) Barton, D. H. R.; McCombie, S. W. New Method for the
Deoxygenation of Secondary Alcohols. J . Chem. Soc., Perkin
Trans. 1 1975, 1574-1585.
(22) Hartwig, W. Modern Methods for the Radical Deoxygenation of
Alcohols. Tetrahedron 1983, 39, 2609-2645.
(23) Barton, D. H. R.; J aszberenyi, J . Cs. Improved Methods for the
Radical Deoxygenation of Secondary Alcohols. Tetrahedron Lett.
1989, 30, 2619-2622.
(24) Gervay, J .; Danishefsky, S. A Stereospecific Route to 2-Deoxy-
â-glycosides. J . Org. Chem. 1991, 56, 5448-5551.
(25) Ohno, M.; Fujita, K.; Nakai, H.; Kobayashi, S.; Inoue, K.; Nojima,
S. An Enantioselective Synthesis of Platelet-Activating Factors,
Their Enantiomers, and Their Analogues from D- and L-Tartaric
Acids. Chem. Pharm. Bull. 1985, 33, 572-582.
(26) Monks, A.; Scudiero, D.; Skehan, P.; Shoemaker, R.; Paull, K.;
Vistica, D.; Hose, C.; Langely, J .; Cronise, P.; Vaigro-Wolff, A.;
Gray-Goodrich, M.; Campbell, H.; Mayo, J .; Boyd, M. Feasibility
of a High-Flux Anticancer Drug Screen Using a Diverse Panel
of Cultured Human Tumor Cell Lines. J . Natl. Canc. Inst. 1991,
83, 757-766.
J M960164J