Glycosidation of alkylamino-alkan-1-ol. A simple and convenient synthesis of glycosylated cationic lipids.

Article abstract of DOI:10.1016/S0960-894X(02)00200-7

Starting from long chain alkylamino-alkan-1-ol a series of amino glycolipids were synthesized. This procedure allows a short and convenient preparation of glycosylated cationic lipids for gene delivery.

Full text of DOI:10.1016/S0960-894X(02)00200-7

Bioorganic & Medicinal Chemistry Letters 12 (2002) 1447–1450
Glycosidation of Alkylamino-alkan-1-ol. A Simple
and Convenient Synthesis of Glycosylated Cationic Lipids
Christophe Jacopin, Marie-Jose Egron, Daniel Scherman and Jean Herscovici*
´
Laboratoire de Chimie Bioorganique et de Biotechnologie Moleculaire et Cellulaire. UMR 7001 CNRS-ENSCP-Aventis-Gencell. 11,
rue Pierre et Marie Curie, 75231 Paris Cedex, France
Received 7 February 2002; revised 27 March 2002; accepted 28 March 2002
Abstract—Starting from long chain alkylamino-alkan-1-ol a series of amino glycolipids were synthesized. This procedure allows a
short and convenient preparation of glycosylated cationic lipids for gene delivery. # 2002 Published by Elsevier Science Ltd.
Long chain dialkylamines like ditetradecylamine or
dioctadecylamine find increasing applications in fields
such as liposomes, cationic lipids, or lipid chelating
agents.1 Connection of dialkylamine with an hydro-
phylic compound at the end of the aliphatic chains
would allow the introduction of new properties like
targeting, aggregation prevention or charge masking.2,3
was treated with 2N sodium methoxide in methanol to
yield the methyl pentadecanoate 2 in 80% yield. The
methyl ester was fused with octadecylamine at 148 ꢀC to
give the amide 3 quantitatively.
Reduction of 3 with lithium aluminium hydride affor-
ded the octadecylamino-pentadecan-1-ol 4 (yield 97%).
Formation of the benzyloxy derivative 5 was performed
by the reaction of 4 with benzylchloroformate in the
presence of triethylamine (yield 70%). Treatment of the
penta-O-acetyl galactopyranose 6 with 1.5 equiv of
We have recently reported4 the preparation of glycoli-
pidic polyamimes and the studies of their physico-che-
mical and transfecting properties. This synthesis has
required a sequence of height steps affording the glyco-
lipidic vector in 20% overall yield (Scheme 1).
As we need to prepare a large amount of these new
transfecting agents, we envisioned a shorter synthesis of
the glycosylated alkylamine by the glycosylation of a
long chain alkylamino-alkan-1-ol (Scheme 2).
Recent reports have described the glycosidation of car-
bohydrates with long chain diols using enolates,5 tri-
chloroacetamidates6 or anhydro sugars7 as glycosyl
donors. We were attracted by another procedure, that
is, the method described by Banoub and Bundle8 for the
glycosylation of a peracetylated carbohydrate with a
hydroxy ester.
Scheme 1. Synthesis of a glycolipidic polyamime.
The synthesis of the 15-(benzyloxycarbonyl-octadecyl-
amino)-pentadecyl-ß-d-2,3,4,6-tetra-O-acetyl-manno-
pyranoside is shown in Scheme 3. The pentadecalone 1
*Corresponding author. Tel.: +33-1-5310-1295; fax: +33-1-5310-
1292; e-mail: herscovi@ext.jussieu.fr
Scheme 2. Glycosylation of long chain alkylamino-alkan-1-ols.
0960-894X/02/$ - see front matter # 2002 Published by Elsevier Science Ltd.
PII: S0960-894X(02)00200-7

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C. Jacopin et al. / Bioorg. Med. Chem. Lett. 12 (2002) 1447–1450
Scheme 3. (i) MeOH rt MeONa (2N in MeOH) 80%; (ii) octadecylamine 148 ꢀC 100%; (iii) LiAlH4 THF 10 h rt 97%; (iv) Benzylchloroformate,
CH2Cl2 triethylamine rt 70%; v SnCl4 0 ꢀC, 30 min then rt 3 h, 69%; (vi) Pd/C 10% H2, MeOH, 100%; (vii) DIPEA, BOP, CHCl3 (83%); (viii) (a)
2 N MeONa in MeOH, (b) Pd/C 10% H2, MeOH, quantitative.
Table 1. Glycosidation of peracetylated hexopyranose
Entry
Peracetylated
glycosides
15-alkylamino-pentadecyl
glycosides
Yield
(%)a
1
2
3
4
5
6
12
13
14
15
7
16
17
18
19
69
50
54
24
26
aAll yields referred to isolated products.
Figure 2.
the monosaccharides the yields range from 50 to 69%.
For the disaccharides (Table entries 4–5), the glycosi-
dation led only to modest yields due to longer reaction
times that probably favored the cleavage of the glycosi-
dic linkage procedure. However, these yields are super-
ior to those recorded for a classical procedure and led
again to a more effective condensation. With the alkyl-
amino-alkyloxy glycosides in hand the synthesis of the
polycationic glycolipid was straightforward (Scheme 3).
Removal of the benzyloxycarbonyl yielded quantita-
tively the glycosides 8, 20, 21. Condensation of the
amine 8 with the CBz carboxyspermine 9 afforded the
protected polycationic glycolipid 10 in 70% yield.
Finally, treatment of 10 with sodium methoxide (2N in
methanol) followed by the hydrogenation (Pd/C) of the
resulting mixture gave the polyamino glycolipid 1110
(yield 100%). In the same fashion, the reaction of
carboxyspermine 9 with amino-glycosides 20 and 21
afforded respectively the fucosylated and the mannosy-
lated polyamino lipids 2211 and 2312 (Figs. 1 and 2).
In summary, we herein report a short and high yield
preparation of cationic glycolipids. The key step of this
synthesis was the direct connection of a long chain sec-
ondary amino alcohol to a peracetylated carbohydrate.
This methodology will be useful for a wide range of
application in lipids and liposomes chemistry.
Figure 1.
tin(IV) chloride for 30 min at 0 ꢀC followed by the
addition of 5 afforded only the 15-(benzyloxy-carbonyl-
octadecyl-amino)-pentadecyl-ß-d-2,3,4,6-tetra-O-acetyl-
manno-pyranoside 7 in 69% yield.9 In the same fashion
the peracetylated glycosides 12–15 were reacted with 5
and the obtained results were outlined in Table 1. For
Acknowledgements
This work was financially supported by the CNRS,
Aventis-Gencell, the Association pour la Recherche sur

C. Jacopin et al. / Bioorg. Med. Chem. Lett. 12 (2002) 1447–1450
1449
le Cancer (ARC) the MENRT and the Region Ile-de-
France (SESAME).
H-4.16 octadecyl), 1.26 (m, 4H, H-13 pentadecyl and H-3
octadecyl), 1.28 (m, 2H, H-17 octadecyl), 1.43 (m, 2H, H-14
pentadecyl), 1.46 (m, 6H, H-2 octadecyl, H-2 and H-3 butyl),
1.51 (m, 2H, H-2 pentadecyl), 1.60 (m, 2H, H-2 propyl), 1.64
(m, 2H, H-2 propyl), 2.62 (m, 2H, H-3-propyl), 2.63 (m, 4H, H-
1 propyl and H-4 butyl), 2.64 (m, 2H, H-1 butyl), 2.72 (m, 2H,
H-3 propyl), 2.74 (m, 2H, H-1 propyl), 3.14 (m, 2H, H-15
pentadecyl), 3.32 (m, 2H, NHCH2CO), 3.35 (m, 2H, H-1 pen-
tadecyl and H-1 octadecyl), 3.53 (m, 1H, H-2 gal), 3.58 (m, 1H,
H-5 gal), 3.60 (m, 1H, H-4 gal), 3.72 (m, 2H, H-6 gal), 4.03 (m,
1H, H-3 gal), 4.17 (m, 2H, H-1 gal).
13C RMN (CDCl3) d 14.09 (C-18 octadecyl), 22.69 (C-17
octadecyl), 25.99 (C-3 pentadecyl), 27.57 (C-3 octadecyl), 27.75
(C-13 pentadecyl), 29.3--30.2 (C-2, C-4, 16 octadecyl, C-4, 12
pentadecyl, C-14 pentadecyl), 32.70 (C-16 octadecyl), 40.23 (C-
1 propyl), 46.24 (C-1 octadecyl), 47.02 (C-15 pentadecyl), 47.63
(C-3-propyl), 48.01 (C-3 propyl), 48.25 (C-1 propyl), 49.64 (C-4
butyl), 50.25 (C-1 butyl), 50.60 (COCH2NH), 61.30 (C-1 pen-
tadecyl), 68.85 (C-6 gal), 70.00 (C-3 gal), 71.51 (C-4 gal), 73.93
(C-5 gal), 74.71 (C-2 gal), 103.64 (C-1 gal), 170.54 (NHCO).
Anal. calcd. for C51H105N5O7, 2 H2O C 65.45, H 11.65, N
7.48. Found C 65.68, H 11.32, N 7.32.
References and Notes
1. For some recent examples in these fields: (a) liposomes;
Tagawa, K.; Sendai, N.; Ohno, K.; Kawaguchi, T.; Kitano,
H.; Matsunaga, T. Bioconjug. Chem. 1999, 10, 354. (b) cationic
lipids; Behr, J. P.; Demeneix, B.; Loeffler, J. P.; Perez-Mutul,
J. Proc. Natl. Acad. Sci. U.S.A. 1989, 86, 6982. Byk, G.;
Dubertret, C.; Escriou, V.; Frederic, M.; Jaslin, G.; Rangara,
R.; Pitard, B.; Crouzet, J.; Wils, P.; Schwartz, B.; Scherman,
D. J. Med. Chem. 1998, 41, 224. Verderone, G.; Van Craynest,
N.; Boussif, O.; Santaella, C.; Bischoff, R.; Kolbe, H. V.;
Vierling, P. J. Med. Chem. 2000, 43, 1367. (c) lipid chelating
agents; Dietrich, C.; Boscheinen, O.; Scharf, K. D.; Schmitt,
L.; Tampe, R. Biochemistry 1996, 35, 1100.
2. Fuhrop, J.-H.; Tank, H. Chem. Phys. Lipids 1987, 43, 193.
3. (a) Ren, T.; Liu, D. Tetrahedron Lett. 1999, 40, 7621. (b)
Banerjee, R.; Mahidhar, Y. V.; Chaudhuri, A.; Gopal, V.;
Rao, N. M. J. Med. Chem. 2001, 44, 4176. (c) Ren, T.; Zhang,
G.; Liu, D. Bioorg. Med. Chem. Lett. 2001, 11, 2969.
4. Jacopin, C.; Hofland, H.; Scherman, D.; Herscovici, J.
Bioorg. Med. Chem. Lett. 2001, 11, 419.
Purification Supelco C-8 reverse phase cartrige (100% water
to 100% acetonitrile then acetonitrile-MeOH 90--10).
11. 2-{3-[4-(3-Amino-propylamino)-butylamino]-propyl-amino}-
N-octadecyl-N-[15-pentadecyl(ß-d-manno-pyranosyl)]-acet-
amide (22).
5. Chenault, K. H.; Castro, A.; Chaflin, L. F.; Yang, J. J.
Org. Chem. 1996, 61, 5024.
6. Kitov, P. I.; Pavel, I.; Railton, C.; Bundle, D. R. Carbo-
hydr. Res. 1998, 307, 361.
7. Timmers, C. M.; Wigchert, S. C. M.; Leeuwenburgh, M. A.;
van der Marel, G. A.; van Boom, J. H. Eur. J. Org. Chem.
1998, 1, 91.
[a]D=0 (c 0.1 MeOH); 1H NMR (pyridine-d6) d ppm 0.77
(m, 3H, H-18 octadecyl), 1.22 (m, 46H, H-3, 12 pentadecyl
and H-4, 17 octadecyl) 1.26 (m, 4H, H-13 pentadecyl and H-3
octadecyl), 1.42 (m, 2H, H-14 pentadecyl), 1.49 (m, 2H, H-2
pentadecyl), 1.52 (m, 2H, H-2 octadecyl), 1.83 (m, 6H, H-2
butyl, H-2 propyl and H-3 butyl), 1.87 (m, 2H, H-2 propyl),
2.71 (m, 4H, H-1 and H-4 butyl), 2.72 (m, 2H, H-3-propyl),
2.88 (m, 4H, H-1 and H-3 propyl), 3.03 (m, 2H, H-1 propyl),
3.18 (m, 2H, H-15 pentadecyl), 3.4 (m, 2H, H-1 pentadecyl),
3.43 (m, 2H, H-1 octadecyl), 3.56 (NHCH2CO), 3.84 (m, 2H,
H-1 pentadecyl), 4.33 (m, 2H, H-6 man), 4.44 (m, 2H, H-6
man), 4.19 (m, 2H, H-4 man), 4.48 (m, 2H, H-2 and H-5 man),
4.57 (m, 2H, H-3 man), 5.24 (m, 2H, H-1 man).
13C NMR (pyridine-d6) d ppm 14.14 (C-18 octadecyl), 22.79
(C-17 octadecyl), 26.45 (C-3 pentadecyl), 27.03 (C-3 octadecyl),
27.26 (C-13 pentadecyl), 29.20–30.2 (C-2, C-4, 15 octadecyl, C-
4, 12 pentadecyl, C-14 pentadecyl), 31.71 (C-2 pentadecyl),
31.99 (C-16 octadecyl), 40.40 (C-1 propyl), 46.97 (C-1 octade-
cyl), 47.61 (C-15 pentadecyl), 47.85 (C-3-propyl), 48.13 (C-3
propyl), 48.46 (C-1 propyl), 48.78 (C-4 butyl), 48.98 (C-1 butyl),
50.55 (COCH2NH), 62.94 (C-1 pentadecyl), 62.94 (C-1 penta-
decyl), 67.38 (C-6 man), 67.38 (C-6 man), 68.99 (C-3 man),
72.05 (C-4 man), 72.98 (C-5 man), 75.10 (C-2 man), 101.42 (C-1
man), 170.98 NHCO). Anal. calcd. for C51H105N5O7, 0.5 H2O
C; 67.40, H; 11.67, N; 7.70. Found C; 67.11, H; 11.32, N; 7.09.
Purification Supelco C-8 reverse phase cartrige (100% water
to 100% acetonitrile then acetonitrile-MeOH 90–10).
8. Banoub, J.; Bundle, D. R. Can. J. Chem. 1979, 57, 2085.
9. Typical experimental for the glycosidation of peracetylated
carbohydrates by alkylamino-1alkan-1-ol: To a solution of 6
(1.5 g, 4.52 mmol) in dry acetonitrile (50 mL) was added
tin(IV) chloride (0.63 mL 5.41 mmol) at 0 ꢀC. The solution was
stirred for 30 min then (15-hydroxy-pentadecyl)-octadecyl car-
bamic acid benzyl ester 5 (3.13 g, 4.97 mmol) was added. After
5 h all 6 has disappeared and the reacting mixture was diluted
with diethyl ether and quenched with sodium hydrogen phos-
phate. The aqueous phase was extracted with diethyl ether and
the combined organic extracts were washed with sodium
hydrogen carbonate and brine, dried (MgSO4). After removal
of the solvent the resulting oil was purified (flash chromato-
graphy, heptane–ethyl acetate 6:4) to give 7 in 69% yield. 7
[a]D=À12 (c 0.66 CH2Cl2); MS (CI), m/e 918 (M+NH4+);
1H NMR (CDCl3) d ppm 0.87 (t, 3H, J=6.96 Hz, H-33), 1.2
(d, 3H, J=6.51 Hz, H-6), 1.25 (m, 54H, (CH2)27), 1.52 (m,
6H, OCH2CH2, H-14 and H-17), 1.95, 2.05 and 2.15 (s, 3H,
OCOCH3), 3.14–3.25 (m, 4H, H-15 and H-16), 3.44 (m, 1H,
OCHaCH2), 3.63 (m, 1H, OCHbCH2), 3.79 (m, 1H, H-5), 4.41
(d, 1H, J=7.98 Hz, H-1), 4.99 (dd, 1H, J=3.52 and 10.46 Hz,
H-3), 5.09 (s, 2H, OCH2Phe), 5.16 (dd, 1H, J=7.98 and
10.46 Hz, H-2), 5.23 (dd, J=3.52 and 3.31 Hz, H-4), 7.32 (m,
5H, Phe).
12. 2-{3-[4-(3-Amino-propylamino)-butylamino]-propyl-amino}-
N-octadecyl-N-[15-pentadecyl-(a-l-6-deoxy-galactopyranosyl)]-
acetamide(23).
13C RMN (CDCl3) d (ppm) 14.7 (C-33), 17.3 (C-2), 20.7
(CH3COO), 27.3 (C-6), 29.72 ((CH2)27), 25.9–32 (OCH2CH2,
C-14, C-17), 47.2–48 (C-15 and C-16), 66.9 (CH2Phe), 69.6
(OCH2CH2), 69.4 (C-2), 70.6 (C-5), 70.8 (C-4), 71.4 (C-3), 96.2
(C-1), 128.4 (Phe), 156.2 and 171.3 (CO). Anal. calcd. for
C53H91NO10 : C, 70.55; H, 10.17; N, 1.55. Found: C, 70.67; H,
10.23; N, 1.71.
10. 2-{3-[4-(3-Amino-propyl-amino)-butylamino]-propylamino}-
N-octadecyl-N-[15-pentadecyl-(ß-d-galactopyranosyl)]-acet-
amide (11).
[a]d=0 (c 0.1 MeOH); 1H NMR (CDCl3) d ppm 0.88 (t, 3H,
m, 1H, H-18 octadecyl), 1.21 (m, 48H, H-3, 13 pentadecyl and
[a]D=0 (c 0.1 MeOH); 1H NMR (CDCl3) d ppm 0.81 (m,
3H, H-18 octadecyl), 1.18 (m, 6H, H-3 octadecyl, H-17 octa-
decyl and H-13 pentadecyl), 1.2 (m, 48H, H-3, 13 pentadecyl
and H-4, 16 octadecyl), 1.22 (m, 2H, H-3 pentadecyl), 1.32 (m,
3H, H-6 fuc), 1.5 (m, 2H, H-2 pentadecyl), 2.51 (m, 2H, H-4
butyl), 2.51 (m, 2H, H-1 butyl), 2.58 (m, 2H, H-3-propyl), 2.59
(m, 2H, H-1 propyl), 2.73 (m, 2H, H-1 propyl), 3.08 (m, 2H,
H-3 propyl), 3.09 (m, 2H, H-1 octadecyl), 3.14 (m, 2H, H-15
pentadecyl), 3.26 (m, 2H, NHCH2CO ), 3.41 (m, 2H, H-1
pentadecyl), 3.48 (m, 2H, H-3 fuc), 3.48 (m, 2H, H-4 fuc), 3.62
(m, 2H, H-5 fuc), 3.76 (m, 2H, H-1 pentadecyl), 3.94 (m, 2H,
H-2 fuc), 4.22 (m, 2H, H-1 fuc).

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C. Jacopin et al. / Bioorg. Med. Chem. Lett. 12 (2002) 1447–1450
13C NMR (CDCl3) d ppm 14.7 (C-18 octadecyl), 16.9 (C-6
69.9 (C-3 fuc), 70.2 (C-1 pentadecyl), 70.2 (C-1 pentadecyl),
70.3 (C-4 fuc), 71.7 (C-5 fuc), 74.5 (C-2 fuc), 104 (C-1 fuc),
171 (NHCO). Anal. calcd for C51H105N5O6, 0.5 H2O C;
68.60, H; 11.88, N; 7.84. Found C; 68.49, H; 11.48, N;
7.03.
fuc), 22.5 (C-17 octadecyl), 26.2 (C-3 pentadecyl), 27.1 (C-3
octadecyl), 27.8 (C-13 pentadecyl), 29.4–30.2, (C-2, C-4.16
octadecyl, C-4.12 pentadecyl, C-14 pentadecyl), 32 (C-2 pen-
tadecyl), 40.6 (C-1 propyl), 46.5 (C-1 octadecyl), 47.2 (C-15
pentadecyl), 47.9 (C-3-propyl), 47.9 (C-3 propyl), 48.3 (C-1
propyl), 48.7 (C-4 butyl), 50 (C-1 butyl), 50.6 (COCH2NH),
Purification Supelco C-8 reverse phase cartrige (100% water
to 100% acetonitrile then acetonitrile–MeOH 90:10).