NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
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2-[(b-D-ribofuranosyl)](Z)-4-(2-(2-nitrophenyl)hydrazono)-3-(trifluoromethyl)-1H-
pyrazol-5(4H)-one (9). Compound 9 was synthesized from 19 according to the general
procedure B. Yellow semi-solid (0.5 g, 90%). UV-vis (MeOH) kmax 230, 395 nm; 1H-
NMR (DMSO-d6) d 7.713–8.48 (4H, m, Ar), 5.63 (1H, d, H-10, J¼4.4 Hz), 5.36 (1H, s,
OH exchangeable with D2O), 5.13 (1H, s, OH exchangeable with D2O), 4.77 (1H, s, OH
exchangeable with D2O), 4.35–4.37 (1H, br dd, H-20), 4.07 (1H, br dd, H-30), 3.83 (1H,
m, H-40), 3.52 (1H, dd, H-50a, J¼4.8, J¼8.0 Hz), 3.43 (1H, dd, H-50b, J¼5.6, J¼11.6 Hz);
19F-NMR (DMSO-d6) d 63.30; 13C-NMR (MHz DMSO-d6) d 172.03, 148.56, 132.87 (q,
C3), 130.95 (q, CF3), 112.21, 120.59, 128.54, 130.96, 86.16, 84.76, 72.03,70.50, 62.12,
45.1. Anal. Clacd for C15H14F3N5O7 (433.30): C, 41.58; H, 3.26; N, 16.16; found C,
41.36; H, 3.28; N, 16.08.
2-[(b-D-Ribofuranosyl](Z)-5-(trifluoromethyl)-4-(2-(2-(trifluoromethyl)phenyl)hydra-
zine-eylidene)-2,4-dihydro-3H-pyrazol-3-one (10). Compound 10 was synthesized
according to the general procedure (C) as described above to give (0.8 gm 89%) as pale
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yellow foam: UV-vis (MeOH) kmax 250, 400 nm; H-NMR (DMSO-d6) d 7.61–8.02 (4H,
m, Ar), 5.63 (1H, br d, H-10), 5.38 (IH, s, OH), 5.15 (1H, s, OH), 4.75 (1H, s, OH), 4.37
(1H, br dd, H-20), 4.08 (1H, br dd, H-30), 3.86 (1H, m, H-40), 3.52 (1H, dd, H-50a, J¼4.4,
J¼11.6 Hz), 3.42 (1H, dd, H-50a, J¼5.6, J¼11.6 Hz); 19F (DMSO-d6) d ꢁ63.52, ꢁ61.60;
13C-NMR (DMSO–d6) d 166.97, 156.27 (q, C3), 142.47, 134.04 (q, CF3), 114.16, 118.19,
120.84, 125.13, 128.66, 130.94, 86.11, 84.85,71.99, 70.43, 62.02; Anal. Clacd for
C16H14F6N4O5 (456.30): C, 42.12; H, 3.09; N, 12.28; found C, 41.91; H, 3.24; N, 12.13.
2-[b-D-Ribofuranosyl](Z)-4-(2-(p-tolyl)hydrazono)-3-(trifluoromethyl)-1H-pyrazol-
5(4H)-one (11). Compound 11 was synthesized according to general procedure (C).
Yield (0.9 g, 90%) as yellow semi-solid. UV-vis (MeOH) kmax 255, 430 nm; 1H-NMR
(DMSO-d6) d 7.28–7.55 (4H, m, Ar), 5.61 (1H, d, H-10, J¼5.2 Hz), 5.34 (1H, d, 20 OH,
J¼6 Hz), 5.11 (1H, d, 30 OH, J¼4.8 Hz), 4.74 (1H, br t, 50-OH0), 4.35 (1H, br dd, H-20)
4.048–4.082 (1H, br dd, H-30) 3.83 (1H, m, H-40), 3.37–3.55 (2H, br dd, H-50a, H-50b),
2.32 (3H, s, CH3); 19F-NMR (DMSO-d6) d ꢁ63.21; 13C-NMR (DMSO–d6) d 156.72,
136.96, 121.65, 117.74–130.1, 86.04, 84.77, 71.97, 70.44, 62, 20; Anal. Clacd for
C16H17F3N4O5 (402.33): C, 47.77; H, 4.39; N, 13.93; found C, 47.56; H, 4.26; N, 13.85.
1,2,3-Tri-O-acetyl-50-deoxy-b-D-ribofuranose (22). Compound 22 was prepared from
D-(þ) ribose according reference (17) with minor modification. 1H-NMR (CDCl3) d 6.1
(1H, d, J¼1.2 Hz), 5.32 (1H, dd, H-2, J¼1.2, J¼4.8 Hz), 5.08 (1H, dd, H3, J¼4.8,
J¼11.6 Hz), 4.26 (1H, m, H-4); 13C-NMR (CDCl3) d 170.01, 169.58, 169.43, 98.43, 78.13,
75.10, 74.79, 21.18, 20.63, 19.84, 1.09.
2-[(5-deoxy-2,3,-Di-O-acetyl-b-D-ribofuranosyl](Z)-4-(2-(3-nitrophenyl)hydrazono)-5-
(trifluoromethyl)-2,4-dihydro-3H-pyrazol-3-one (23). Compound 23 was prepared by
coupling of 4 with 22 according to general procedure (B). Yield (1.3 g, 78%) as a yellow
foam: UV-vis (MeOH) kmax 230, 390 nm; 1H-NMR (CDCl3) d 13.55 (1H, s, NH);
7.62–8.28 (4H, m, Ar), 5.94 (1H, d, H-10, J¼4.0 Hz), 5.72 (1H, br dd, H-20), 5.23 (1H, br
dd, H-30), 4.26 (1H, m, H-40), 2.12 (6H, s, Ac), 1.42 (3H, d, 50CH3, J¼6.4 Hz); 19F (CDCl3)
d ꢁ64.57; 13C-NMR (CDCl3) d [169.90, 169.73 (2Ac)], 157.90 (C¼O), 149.45 (C-3), 141.61
(C-4), 137.54 (q, CF3), 111.71–131.07 (Ar), 85.24, 78.36, 74.93, 73.09, 20.65, 20.74, 18.85;
Anal. Clacd for C19H18F3N5O8 (501.38): C, 45.52; H, 3.62; N, 13.97; found C, 45.59; H,
3.72; N, 13.81.
2-[(5-deoxy-2,3,-Di-O-acetyl-b-D-ribofuranosyl](Z)-4-[(2-nitrophenyl)hydrazono)]-3-
(trifluoromethyl)-1H-pyrazol-5(4H)-one (24). Compound 24 was prepared by coupling
of 5 with 22 according to general procedure (B). Yield (1.2 g, 72%). as a yellow foam.
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UV-vis (MeOH) kmax 230, 295 nm; H-NMR (CDCl3) d 13.61 (1H, s NH) 7.63–8.28 (4H,