Synthesis of an Immunomodulatory Phosphoglycolipid
FULL PAPER
chromatography on silica gel (hexanes/EtOAc=2:1–1:2) to give 25 in
90% yield. Rf =0.38 (hexanes/EtOAc=1:1); [a]2D9 =+70.96 (c=1 in
EtOAc); 1H NMR (400 MHz, CDCl3): d=0.07 (s, 3H; TBDMS), 0.10 (s,
3H; TBDMS), 0.87 (s, 9H; TBDMS), 1.78 (s, 3H; (CO)CH3), 2.38 (d, J=
7.9 Hz, 1H; OH), 2.54 (d, J=4.0 Hz, 1H; OH), 3.42 (td, J=2.2, 7.9 Hz,
1H; 3’-H), 3.52 (dd, J=7.2, 10.3 Hz, 1H; 1’-H), 3.62–3.71 (m, 5H; 3-H,
4-H, 5-H, 6-H, 1’-H), 3.75–3.76 (m, 1H; 6-H), 4.05–4.09 (2H; m, 2’-H, 4’-
H), 4.22 (td, J=3.5, 9.4 Hz, 1H; 2-H), 4.49 (d, J=10.8 Hz, 1H; PhCH2),
4.51 (d, J=12.2 Hz, 1H; PhCH2), 4.60 (d, J=12.2 Hz, 1H; PhCH2), 4.61
(d, J=11.4 Hz, 1H; PhCH2), 4.78 (d, J=3.5 Hz, 1H; 1-H), 4.79 (d, J=
10.8 Hz, 1H; PhCH2), 4.81 (d, J=11.4 Hz, 1H; PhCH2), 5.26 (dt, J=1.2,
10.4 Hz, 1H; 6’-H), 5.34 (dt, J=1.0, 16.2 Hz, 1H; 6’-H), 5.53 (d, J=
9.4 Hz, 1H; NH), 5.99 (ddd, J=6.0, 10.4, 16.2 Hz, 1H; 5’-H), 7.14–
7.34 ppm (m, 15H; ArH); 13C NMR (100 MHz, CDCl3): d=ꢀ5.01, ꢀ4.52,
17.77, 23.10, 25.59, 52.36, 68.39, 68.49, 70.03, 71.22, 72.84, 73.25, 73.34,
74.59, 74.88, 78.22, 79.83, 98.73, 116.56, 127.50, 127.64, 127.86, 128.14,
128.22, 128.25, 128.33, 137.74, 137.77, 138.17, 138.45, 169.91 ppm; HRMS
(ESI): m/z calcd for C41H57NO9NaSi [M+Na]+: 758.3700; found:
758.3691.
2H; 2-H, 2’-H), 4.55 (d, J=12.1 Hz, 1H; PhCH2), 4.63 (d, J=11.5 Hz,
2H; PhCH2), 4.74–4.83 (m, 5H; 1-H, PhCH2, NH), 7.13 (d, J=9.0 Hz,
1H; NH), 7.23–7.40 ppm (m, 15H; ArH); 13C NMR (100 MHz,
CD3COCD3/CDCl3 =10:1): d=14.42, 23.25, 23.33, 27.69, 30.07, 30.36,
30.56, 32.63, 39.68, 53.85, 69.85, 70.90, 71.83, 72.25, 73.75, 75.35, 75.49,
79.38, 81.87, 98.98, 128.10, 128.18, 128.22, 128.36, 128.48, 128.57, 128.96,
128.99, 129.06, 139.59, 139.70, 140.04, 170.22, 171.90 ppm; HRMS (ESI):
m/z calcd for C43H60N2O8Na [M+Na]+: 755.4247; found: 755.4246.
Compounds 28 and 29: DMAP (10.1 mg, 0.08 mmol) and DCC (364 mg,
1.76 mmol) were added to a solution of fatty acid (0.83 mmol) and 3-O-
benzyl-sn-glycerol (27; 189 mg, 1.04 mmol) in a mixture of CH2Cl2/DMF
(7 mL, 5:1) at 08C. The reaction mixture was stirred at 08C for 1 h and
then warmed to room temperature with stirring for an additional 12 h.
The mixture was then filtered through Celite. The solvent was removed
in vacuo and the residue was purified by flash column chromatography
on silica gel (hexanes/EtOAc=25:1–15:1, v/v) to give 28 (65%) or 29
(72%).
28: Rf =0.58 (hexanes/EtOAc=2:1); [a]2D9 =ꢀ3.51 (c=1 in EtOAc);
1H NMR (400 MHz, CDCl3): d=0.86 (t, J=6.2 Hz, 3H; CH3), 1.23 (m,
28H; CH2), 1.58 (m, 2H; 5’-H), 2.30 (t, J=7.5 Hz, 2H; 4’-H), 2.49 (d, J=
4.4 Hz, 1H; OH), 3.45–3.55 (m, 2H; 1’-H), 4.01–4.02 (1H; m, 2’-H),
4.10–4.19 (m, 2H; 3’-H), 4.54 (s, 2H; PhCH2), 7.31–7.36 ppm (m, 5H;
ArH); 13C NMR (100 MHz, CDCl3): d=14.11, 22.68, 24.89, 29.11, 29.24,
29.35, 29.45, 29.68, 31.91, 34.14, 65.32, 68.93, 70.83, 73.50, 127.74, 127.87,
128.47, 137.64, 173.96 ppm; HRMS (ESI): m/z calcd for C28H48O4Na
[M+Na]+: 471.3450; found: 471.3441.
29: Rf =0.50 (hexanes/EtOAc=2:1); [a]2D9 =ꢀ3.97 (c=1 in EtOAc);
1H NMR (400 MHz, CDCl3): d=0.84 (d, J=6.6 Hz, 6H; two CH3 over-
lapping each other), 1.12–1.23 (m, 22H; CH2), 1.46–1.54 (m, 1H; CH),
1.55–1.60 (m, 2H; 5’-H), 2.30 (t, J=7.5 Hz, 2H; 4’-H), 2.56 (d, J=4.8 Hz,
1H; OH), 3.47 (dd, J=6.1, 9.6 Hz, 1H; 1’-H), 3.53 (dd, J=4.3, 9.6 Hz,
1H; 1’-H), 3.90–4.04 (m, 1H; 2’-H), 4.09–4.18 (m, 2H; 3’-H), 4.54 (s, 2H;
PhCH2), 7.26–7.36 ppm (m, 5H; ArH); 13C NMR (100 MHz, CDCl3): d=
22.50, 24.72, 27.27, 27.80, 28.97, 29.11, 29.32, 29.46, 29.54, 29.79, 33.95,
38.90, 65.16, 68.61, 70.81, 73.27, 127.56, 127.64, 128.26, 137.54,
173.73 ppm; HRMS (ESI): m/z calcd for C27H46O4Na [M+Na]+:
457.3294; found: 457.3296.
Compounds 3a and 3b: PbACHTUNGTRNEGNU(OAc)4 (165 mg, 0.37 mmol) and Na2CO3
(39.3 mg, 0.37 mmol) were added to a solution of 25 (260 mg, 0.35 mmol)
in CH2Cl2 (3.5 mL) at 08C. The reaction mixture was stirred at room
temperature for 1 h and ethylene glycol (0.2 mL) was then added. The re-
sulting solution was stirred for an additional 10 min and then the reaction
mixture was passed through a pad of Celite. The filtrate was washed with
a saturated aqueous solution of NaHCO3, dried over MgSO4, and con-
centrated under reduced pressure. The resulting aldehyde was dissolved
in
a mixture of tBuOH/H2O (2.4 mL, 1:1), and 2-methyl-2-butene
(0.37 mL, 3.53 mmol) was added. A freshly prepared solution of NaClO2
(92 mg, 1.06 mmol)/NaH2PO4·2H2O (265 mg, 1.76 mmol) in tBuOH/H2O
(1.0 mL, 1:1) was added at 08C. The reaction mixture was stirred at this
temperature for 30 min followed by stirring at room temperature for an-
other 3 h. The solvent was then removed under reduced pressure and the
residue purified by flash column chromatography on silica gel to give the
desired acid. After acetylation using pyridine (2.1 mL, 0.02 mmol) and
Ac2O (1.5 mL, 0.02 mmol), the residue (106 mg, 0.17 mmol) was dis-
solved in dry CH2Cl2 (1.7 mL). To this solution, EDC (65.4 mg,
0.34 mmol), HOBt (45.1 mg, 0.34 mmol), lipid amine (0.34 mmol), and
NEt3 (0.05 mL, 0.34 mmol) were added successively and the resulting
mixture was stirred at room temperature for 12 h. The reaction mixture
was then diluted with CH2Cl2 and washed successively with 10% aqueous
HCl, saturated aqueous NaHCO3, and brine. The organic layer was dried
over MgSO4, concentrated, and subjected to flash column chromatogra-
phy on silica gel to give the product with added lipid. After deacetylation
of the above lipid with NaOMe (0.10 mmol) in methanol, the reaction
mixture was neutralized with IR-120 and purified by column chromatog-
raphy on silica gel (CH2Cl2 100% to 3% MeOH in CH2Cl2) to give 3a
(42% yield for five steps) or 3b (60% yield for five steps).
3a: Rf =0.56 (MeOH/CH2Cl2 =1:12); [a]2D9 = +71.89 (c=1 in EtOAc);
1H NMR (400 MHz, CD3(CO)CD3): d=0.90 (d, J=6.6 Hz, 6H; two CH3
overlapping each other), 1.18–1.31 (m, 24H; CH2), 1.53–1.61 (m, 3H;
CH, CH2), 1.93 (s, 3H; (CO)CH3), 3.18–3.35 (m, 2H; 3’-H), 3.68–3.86 (m,
5H; 3-H, 4-H, 6-H, 1’-H), 3.88–3.92 (m, 1H; 5-H), 3.96 (dd, J=5.1,
10.2 Hz, 1H; 1’-H), 4.24–4.29 (m, 2H; 2-H, 2’-H), 4.58 (d, J=12.1 Hz,
1H; PhCH2), 4.66 (d, J=11.3 Hz, 2H; PhCH2), 4.78–4.86 (m, 4H; 1-H,
PhCH2), 4.92 (d, J=5.6 Hz, 1H; NH), 7.23 (d, J=9.6 Hz, 1H; NH), 7.28–
7.44 ppm (m, 15H; ArH); 13C NMR (100 MHz, CD3COCD3): d=23.00,
23.23, 23.38, 27.76, 28.19, 28.72, 29.76, 29.96, 30.13, 30.15, 30.34, 30.44,
30.47, 30.54, 30.64, 30.71, 39.71, 39.84, 53.92, 69.96, 70.89, 71.88, 72.29,
73.77, 75.39, 75.55, 79.49, 81.91, 81.93, 99.01, 128.16, 128.24, 128.28,
128.43, 128.55, 128.64, 129.03, 129.04, 129.06, 129.13, 139.73, 139.82,
140.16, 171.14, 171.92 ppm; HRMS (ESI): m/z calcd for C49H72N2O8Na
[M+Na]+: 839.5186; found: 839.5185.
Compounds 30 and 31: DMAP (0.08 mmol) and DCC (0.78 mmol) were
added to a solution of glycerol 28 or 29 (0.39 mmol) and fatty acid
(0.47 mmol) in CH2Cl2 (3.9 mL) at room temperature. The mixture was
stirred for 20 h and then filtered through Celite. The solvent was then re-
moved under reduced pressure and the resulting oil was purified by flash
column chromatography on silica gel (hexanes/EtOAc=1:0–20:1, v/v) to
give 30 (91% yield) or 31 (97% yield).
30: Rf =0.61 (hexanes/EtOAc=4:1); [a]2D9 =ꢀ6.53 (c=1 in EtOAc);
1H NMR (400 MHz, CDCl3): d=0.84–0.88 (m, 6H; two CH3 overlapping
each other), 1.23 (m, 52H; CH2), 1.55–1.61 (m, 4H; CH2), 2.24–2.32 (m,
4H; 4’-H, 5’-H), 3.56–3.58 (m, 2H; 1’-H), 4.17 (dd, J=6.4, 11.9 Hz, 1H;
3’-H), 4.33 (dd, J=3.8, 11.9 Hz, 1H; 3’-H), 4.50 (d, J=12.1 Hz, 1H;
PhCH2), 4.54 (d, J=12.1 Hz, 1H; PhCH2), 5.20–5.25 (m, 1H; 2’-H), 7.25–
7.35 ppm (m, 5H; ArH); 13C NMR (100 MHz, CDCl3): d=14.00, 22.59,
24.76, 24.83, 28.98, 29.01, 29.20, 29.29, 29.40, 29.59, 29.62, 31.84, 33.95,
34.16, 62.49, 68.09, 69.85, 73.13, 127.46, 127.60, 128.24, 137.58, 172.84,
173.12 ppm; HRMS (ESI): m/z calcd for C44H78O5Na [M+Na]+:
709.5747; found: 709.5737.
31: Rf =0.71 (hexanes/EtOAc=4:1); [a]2D9 =ꢀ7.29 (c=1 in EtOAc);
1H NMR (400 MHz, CDCl3): d=0.84 (d, J=6.6 Hz, 12H; four CH3 over-
lapping each other), 1.12–1.24 (m, 40H; CH2), 1.46–1.57 (m, 2H; CH),
1.58–1.61 (m, 4H; CH2), 2.24–2.32 (m, 4H; 4’-H, 5’-H), 3.57 (d, J=
5.2 Hz, 2H; 1’-H), 4.17 (dd, J=6.4, 11.9 Hz, 1H; 3’-H), 4.33 (dd, J=3.8,
11.9 Hz, 1H; 3’-H), 4.49 (d, J=12.1 Hz, 1H; PhCH2), 4.54 (d, J=12.1 Hz,
1H; PhCH2), 5.20–5.23 (m, 1H; 2’-H), 7.26–7.34 ppm (m, 5H; ArH);
13C NMR (100 MHz, CDCl3): d=22.62, 24.84, 24.92, 27.39, 27.93, 29.06,
29.09, 29.26, 29.45, 29.64, 29.66, 29.92, 34.08, 34.29, 39.03, 62.61, 68.22,
69.96, 73.26, 127.58, 127.73, 128.37, 137.67, 173.06, 173.35 ppm; HRMS
(ESI): m/z calcd for C42H74O5Na [M+Na]+: 681.5434; found: 681.5436.
3b: Rf =0.51 (MeOH/CH2Cl2 =1:9); [a]2D9 = +149.29 (c=1 in CH2Cl2);
1H NMR (400 MHz, CD3(CO)CD3): d=0.85–0.88 (m, 3H; CH3), 1.24–
1.28 (m, 16H; CH2), 1.50–1.52 (m, 2H; CH2), 1.89 (s, 3H; (CO)CH3),
3.11–3.27 (m, 2H; 3’-H), 3.64–3.82 (m, 5H; 3-H, 4-H, 6-H, 1’-H), 3.85–
3.89 (m, 1H; 5-H), 3.91 (dd, J=5.1, 10.2 Hz, 1H; 1’-H), 4.19–4.25 (m,
Compounds 32 and 33: Acetic acid (0.27 mL) and palladium on charcoal
(Pd/C) (24 mg, 10% Pd content) were added to a solution of glycerol 30
Chem. Eur. J. 2013, 00, 0 – 0
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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