Crauste et al.
JOCNote
PEG-supported nucleoside H-phosphonate was precipitated
from a dichloromethane solution by addition of an excess
volume of cold diethyl ether (25 mL). The precipitate was
filtered and washed with diethyl ether. The final product was
recrystallized from ethyl alcohol absolute (5 mL) and dried
under vacuum over KOH pellets.
Poly(ethylene glycol)4000 Bis[4-N-(1-(20,30-dideoxy-50-hydro-
geno-phosphonyl-β-D-ribofuranosyl)-cytosyl) succinate], Triethy-
lammonium Salt (3a). PEG-ddC 1b (0.25 g, 0.05 mmol) was
treated as previously described and afforded compound 3a as a
diethyl ether. Compound 2a (containing 16% of remaining starting
material 3a) was obtained as a white solid (0.09 g, 89%). δH (D2O,
300 MHz) 8.49 (d, J6-5 = 7.5 Hz, 1H, H6), 7.13 (d, J5-6 = 7.3 Hz,
0
0
1H, H5), 5.98 (d, J1 -2 = 5.1 Hz, 1H, H1 ), 4.35 (m, 1H, H4 ), 4.19
0
0
0
0
(m,3H,(OCH2R)PEG H5 a),3.98-3.92(m,1H,H5 b),3.85-3.36(m,
(OCH2)PEG), 3.10 (q, J = 7.2 Hz, 6H, (CH3CH2)3NH), 2.79-2.68
0
(m, 4H, CH2succ), 2.46 (m, 1H, H2 a), 2.08 (m, 1H, H2 b), 1.97 (m,
0
0
1H, H3 a), 1.83 (m, 1H, H3 b), 1.18 (t, J = 7.2 Hz, 9H, (CH3-
0
CH2)3NH); δC (D2O, 100 MHz) 174.5, 174.5 (2s, CdOsucc), 161.9 (s,
0
C4), 156.0 (s, C2), 146.3 (s, C6), 97.4 (s, C5), 88.3 (s, C1 ), 81.8 (d,
0
0
white solid (0.23 g, 86%). δH (D2O, 300 MHz) 8.34 (d, J6-5
7.4 Hz, 1H, H6), 7.26 (d, J5-6 = 7.4 Hz, 1H, H5), 6.67 (d, JH-P
=
=
0
JC4 -P=9.0 Hz, C4 ), 69.5 (s, (OCH2)PEG), 68.4 (s, (OCH2β)PEG),
0
65.2 (s, C5 ), 64.1(s, (OCH2R)PEG), 46.6 (s, (CH3CH2)3NH), 32.6(s,
C2 ), 31.5, 28.4 (s, CH2succ), 23.8 (s, C3 ), 8.2 (s, (CH3CH2)3NH); δP
(D2O, 121 MHz) 0.37 (s).
0
0
0
637.2 Hz, 1H, HHP), 5.99 (m, 1H, H1 ), 4.32 (m, 1H, H4 ),
0
0
4.18-4.09 (m, 3H, (OCH2R)PEG H5 a), 3.94 (m, 1H, H5 b),
3.83-3.36 (m, (OCH2)PEG), 3.09 (q, J = 7.2 Hz, 6H, (CH3-
Poly(ethylene glycol)4000 Bis[4-N-(1-(20,30-dideoxy-50-O-
mono phosphoryl-30-thia-β-L-ribofuranosyl)-cytosyl) succinate],
Triethylammonium Salt (2b). To a solution of PEG-3TC 50-HP
3b (0.15 g, 0.03 mmol) in anhydrous pyridine (2.50 mL) was
added N,O-bis(trimethyl silyl)acetamide (0.30 mL, 1.21
mmol). The solution was stirred at 50 °C for 4 h, the mixture
was cooled to 0 °C, and then oxidation was carried out by
addition of an iodine solution (200 mM, 75 mg, 0.30 mmol) in
pyridine-water (56/44, v/v, 1.50 mL) at room temperature.
The mixture was stirred for 1 h, treated by an excess amount
of MeOH and NEt3 (1/1, v/v, 1.50 mL), and stirring was
pursued for 1 h. The solvents were evaporated under reduced
pressure, and the residue was dissolved in dichloromethane
(15 mL). The organic layer was washed with aqueous sodium
thiosulfate solution 5% (10 mL), and the aqueous layer was
extracted several times by dichloromethane (15 mL). The
organic layers were combined and evaporated under reduced
pressure. The support-bound nucleosid-50-yl phosphate was
precipitated from a dichloromethane solution, by addition
of an excess volume of cold diethyl ether (150 mL). The
precipitate was filtered and washed with diethyl ether. The
final product was recrystallized from ethyl alcohol absolute
(5 mL) and dried under vacuum over KOH pellets. Com-
0
CH2)3NH), 2.82-2.66 (m, 4H, CH2succ), 2.45 (m, 1H, H2 a),
0
0
0
2.08-1.97 (m, 2H, H2 b H3 a), 1.78 (m, 1H, H3 b), 1.17 (t, J = 7.2
Hz, 9H, (CH3CH2)3NH); δC (D2O, 75 MHz) 174.5, 174.4 (2s,
CdOsucc), 162.3 (s, C4), 156.9 (s, C2), 146.8 (s, C6), 97.6 (s, C5),
0
0
88.2 (s, C1 ), 86.6 (d, JC4 -P = 7.6 Hz, C4 ), 69.6 (s, (OCH2)PEG),
0
0
68.4 (s, (OCH2β)PEG), 64.1 (s, (OCH2R)PEG), 63.9 (d, JC5 -P
=
3.9 Hz, C5 ), 46.6 (s, (CH3CH2)3NH), 32.5 (s, C2 ), 31.5, 28.5 (2s,
0
0
0
CH2succ), 24.1 (s, C3 ), 8.2 (s, (CH3CH2)3NH); δP (D2O, 121
MHz) 6.53 (s).
Poly(ethylene glycol)4000 Bis[4-N-(1-(20,30-dideoxy-50-hydro-
geno-phosphonyl-30-thia-β-L-ribofuranosyl)-cytosyl) succinate],
Triethylammonium Salt (3b). PEG-3TC 1b (0.30 g, 0.06 mmol)
was treated as previously described and afforded compound 3b
as a white solid (0.28 g, 87%). δH (D2O, 300 MHz) 8.39 (d,
J6-5 = 7.4 Hz, 1H, H6), 7.26 (d, J5-6 = 7.4 Hz, 1H, H5), 6.71 (d,
0 0
JH-P = 641.9 Hz,1H, HHP), 6.25 (s, 1H, H1 ), 5.40 (s, 1H, H4 ),
0
0
4.29-4.13 (m, 4H, (OCH2R)PEG H5 a H5 b), 3.85-3.36 (m,
0
0
OCH2)PEG H2 a), 3.22 (m, 1H, H2 b), 3.10 (q, J = 7.2 Hz, 6H,
(CH3CH2)3NH), 2.79-2.65 (m, 4H, CH2succ), 1.18 (t, J = 7.2
Hz, 9H, (CH3CH2)3NH); δC (D2O, 100 MHz) 174.6, 174.5 (2s,
CdOsucc), 162.6 (s, C4), 156.6 (s, C2), 146.1 (s, C6), 97.6 (s, C5),
0
88.0 (s, C1 ), 86.1 (s, C4 ), 69.6 (s, (OCH2)PEG), 68.4 (s,
0
0
(OCH2β)PEG), 64.2 (s, (OCH2R)PEG), 63.5 (s, C5 ), 46.5 (s,
pound 2b was obtained as a yellow solid (0.14 g,
quantitative). δH (D2O, 300 MHz) 8.44 (d, J6-5 = 7.5 Hz,
0
(CH3CH2)3NH), 37.8 (s, C2 ), 31.6, 28.5 (2s, CH2succ), 8.1 (s,
0
1H, H6), 7.26 (d, J5-6 = 7.5 Hz, 1H, H5), 6.25 (s, 1H, H1 ),
(CH3CH2)3NH); δP (D2O, 121 MHz) 6.35 (s).
0
0
0
Procedures for H-Phosphonate Oxidation. Poly(ethylene glycol)-
4000 Bis[4-N-(1-(20,30-dideoxy-50-O-monophosphoryl-β-D-ribofuran-
osyl)-cytosyl) succinate], Triethylammonium Salt (2a). To a solution
of PEG-ddC 50-HP 3a (0.10 g, 0.02 mmol) in anhydrous acetonitrile
(1.50 mL) were added N,O-bis(trimethylsilyl) acetamide (0.20 mL,
0.81 mmol) and anhydrous triethylamine (0.06 mL, 0.40 mmol). The
solution was stirred at 50 °C during 4 h, the mixture was cooled to
0 °C, and oxidation was carried out by addition of tert-butyl
hydroperoxide (5-6 M solution in decane, 2.00 mmol, 0.36 mL).
The mixture was stirred for 3 h at room temperature, then treated by
an excess amount of MeOH and NEt3 (1/1, v/v, 0.50 mL), and
stirring was pursued for 1 h. The solvents were evaporated under
reduced pressure, and the residue was dissolved in dichloromethane
(10 mL). The organic layer was washed with aqueous sodium
bicarbonate solution (5%, w/v, 7 mL), and the aqueous layer was
extracted several times by dichloromethane (10 mL). The organic
layers were combined and evaporated under reduced pressure. The
support-bound nucleosid-50-yl phosphate was precipitated from a
dichloromethane solution by addition of an excess volume of cold
diethyl ether (100 mL). The precipitate was filtered and washed with
5.40 (s, 1H, H4 ), 4.42-4.07 (m, 4H, (OCH2R)PEG H5 a H5 b),
0
0
3.84-3.36 (m, (OCH2)PEG H2 a), 3.20 (m, 1H, H2 b), 3.10 (q,
J = 7.2 Hz, 6H, (CH3CH2)3NH), 2.82-2.67 (m, 4H, CH2succ),
1.15 (t, J = 7.2 Hz, 9H, (CH3CH2)3NH); δC (D2O, 75 MHz)
174.6, 174.5 (2s, CdOsucc), 162.6 (s, C4), 156.6 (s, C2), 146.3 (s, C6),
0
97.6 (s, C5), 88.1 (s, C1 ), 86.2 (d, JC4 -P = 8.4 Hz, C4 ), 69.6 (s,
0
0
0
(OCH2)PEG), 68.4 (s, (OCH2β)PEG), 64.8 (s, C5 ), 64.1 (s,
0
(OCH2R)PEG), (s, (CH3CH2)3NH), 37.9 (s, C2 ), 31.6, 28.5 (s,
CH2succ), (s, (CH3CH2)3NH); δP (D2O, 121 MHz) 0.72 (s).
Acknowledgment. C.C. is grateful to the French Ministry
of Education and Research (MENRT) for a Ph.D. grant, and
the authors thank the “Centre National de la Recherche
Scientifique” (CNRS) for funding and M. C. Bergogne for
manuscript editing.
Supporting Information Available: Experimental proce-
dures and NMR spectra. This material is available free of charge
1000 J. Org. Chem. Vol. 76, No. 3, 2011