´
Jeannot, Gosselin, and Mathe
2200
for 12 hours, then neutralised with a 1N chlorhydric acid solution. After evaporation
under reduced pressure the crude product was subjected to silica gel column chroma-
tography using a stepwise gradient of methanol (10–50%) in dichloromethane to afford
9-(3-C-trifluoromethyl-b-D-ribofuranosyl)guanine (0.4 g, 74%) which was crystallised
20
from water after filtration over Millex HV filter. Melting point > 350ꢀC. ½aꢃD þ 4
1
(c ¼ 1.01, DMSO). UV (Ethanol 95) lmax 252 nm, (e 9500). NMR H (DMSO-d6,
400 MHz) d 10.75 (1H, br s, N-H), 8.07 (1H, s, H-8), 6.56 (3H, br s, NH2 þ OH),
0
0
0
6.25 (1H, br s, OH), 5.78 (1H, d, J1 -2 ¼ 7.8 Hz, H-1 ), 5.19 (1H, t, J ¼ 4.8 Hz, OH-
50), 4.93 (1H, d, H-20), 4.04 (1H, m, H-40), 3.69 (2H, m, H-50 and H-500). NMR 13C
(DMSO-d6, 100 MHz) d 157.6 (C-6), 154.7 (C-2), 152.7 (C-4), 136.6 (C-8), 125.6 (q,
2
1JC-F ¼ 284.5 Hz, CF3), 117.5 (C-5), 86.1 (C-40), 85.4 (C-10), 78.6 (q, JC-F ¼ 28.4 Hz,
C-30), 73 (C-20), 60.8 (C-50). NMR 19F (DMSO-d6, 235 MHz) d ꢁ73.9 (s, CF3). Anal.
Calcd. for C11H12F3N5O5.0.9 H2O : C, 35.96, H, 3.79, N, 19.06, F, 15.51. Found : C,
36.09, H, 3.57, N, 18.71, F, 15.27.
1-(3-C-Trifluoromethyl-b-D-ribofuranosyl)uracil (3). The preparation of com-
pound 3 was achieved following a protocol already reported in the literature.[6]
20
Melting point ¼ 267–268ꢀC (mp > 250ꢀC lit.[6]). ½aꢃD þ 3 (c ¼ 1.05, DMSO). UV
1
(Ethanol 95) lmax 258 nm, (e 10900). NMR H (DMSO-d6, 400 MHz) d 11.57 (1H,
br s, N-H), 8.11 (1H, d, J6-5 ¼ 8.1 Hz, H-6), 6.69 (1H, br s, OH), 6.29 (1H, br s,
0
0
0
0
OH), 6.05 (1H, d, J1 -2 ¼ 7.8 Hz, H-1 ), 5.87 (1H, d, H-5), 5.34 (1H, br s, OH-5 ),
4.55 (1H, d, H-20), 4.12 (1H, m, H-40), 3.78 (2H, m, H-50 and H-500). NMR 13C
1
(DMSO-d6, 100 MHz) d 163.8 (C-4), 151.8 (C-2), 141.8 (C-6), 125.5 (q, JC-F
¼
2
280 Hz, CF3), 103.4 (C-5), 86.4 (C-10), 85.6 (C-40), 78.6 (q, JC-F ¼ 28.6 Hz, C-30),
72.6 (C-20), 60.6 (C-50). NMR 19F (DMSO-d6, 235 MHz) d ꢁ74.1 (s, CF3). SM FABþ
(GT) m=z 313 (M þ H)þ, 201 (S)þ, 113 (BH2)þ. FABꢁ (GT) m=z 311 (M ꢁ H)ꢁ, 111
(B)ꢁ. Anal. Calcd. for C10H11F3N2O6 : C, 38.47, H, 3.55, N, 8.97. Found: C, 38.82,
H, 3.65, N, 9.00.
1-(3-C-Trifluoromethyl-b-D-ribofuranosyl)thymine (4). The preparation of
compound 4 was achieved following a protocol already reported in the literature.[6]
20
1
½aꢃD þ 1 (c ¼ 1.00, DMSO). UV (Ethanol 95) lmax 263 nm, (e 10300). NMR H
(DMSO-d6, 400 MHz) d 11.00 (1H, br s, N-H), 7.84 (1H, d, J6-CH3 ¼ 0.8 Hz, H-6),
0
0
0
6.30 (1H, br s, OH), 5.94 (1H, d, J1 -2 ¼ 8 Hz, H-1 ), 5.30 (1H, br s, OH), 4.47
(1H, d, H-20), 4.00 (1H, m, H-40), 3.68 (2H, m, H-50 and H-500), 1.86 (3H, s, CH3).
NMR 13C (DMSO-d6, 100 MHz) d 164.6 (C-4), 152.0 (C-2), 137.1 (C-6), 125.6 (q,
1JC-F ¼ 285 Hz, CF3), 110.9 (C-5), 86.1 (C-10), 85.5 (C-40), 78.5 (q, JC-F ¼ 28.9 Hz,
2
C-30), 72.3 (C-20), 60.6 (C-50), 13.0 (CH3). NMR 19F (DMSO-d6, 235 MHz)
d ꢁ74.0 (s, CF3). SM FABþ (GT) m=z 327 (M þ H)þ, 127 (BH2)þ. FABꢁ (GT)
m=z 325 (M ꢁ H)ꢁ, 125 (B)ꢁ. Anal. Calcd. for C11H13F3N2O6.0.9 H2O : C, 38.58,
H, 4.36, N, 8.18,.F 16,64. Found : C, 38.69, H, 4.22, N, 8.10, F 16.60.
1-(3-C-Trifluoromethyl-b-D-ribofuranosyl)cytosine (5). A solution of 1-(2,3-di-
O-acetyl-5-O-benzoyl-3-C-trifluoromethyl-b-D-ribofuranosyl)uracil[6] (0.804 g, 1.61 mmol)
and 1-methyl-pyrrolidine (1.6 mL, 15.38 mmol) in anhydrous acetonitrile (8 mL)
was cooled to 0ꢀC. Trifluoroacetic anhydride (0.57 mL, 4.03 mmol) was then added.
After 45 minutes at 0ꢀC, 4-nitrophenol (0.67 g, 4.82 mmol) was added to the