184
S. Korouli et al.
LETTER
3.97 (m, 1 H, H-3¢), 4.40 (m, 2 H, CH2), 4.43 (m, 1 H, H-2¢),
4.47 (m, 2 H, CH2), 4.56 (m, 2 H, CH2), 4.70 (m, 1 H, H-4¢),
5.85 (s, 1 H, =CH), 6.79 (d, J5,6 = 5.62 Hz, 1 H, H-5), 7.18–
7.42 (m, 15 H, PhH), 8.45 (d, J6,5 = 5.62 Hz, 1 H, H-6), 8.79
(br s, D2O exch., 1 H, NH). 13C NMR (CDCl3): d = 56.10
(CH3O), 68.52 (C-5¢), 71.28 (CH2), 72.27 (CH2), 72.52
(=CH), 72.99 (C-2¢), 73.20 (CH2), 75.80 (C-3¢), 76.89 (C-1¢),
85.18 (C-4¢), 105.81 (C-5), 107.52, 113.25, 118.99, 124.73
(CF3CO), 118.15 (C-3), 127.61, 127.81, 128.10, 128.16,
128.22, 128.31, 128.41, 128.51, 128.56, 137.04, 137.47
(CPh), 147.07 (C-6), 150.04 (C-2), 153.80, 154.52, 155.26,
155.99 (CF3CO), 163.17 (C-4). Anal. Calcd for
(CF3CO), 119.35 (C-3), 150.32 (C-6), 154.98 (C-2), 154.18,
154.91, 155.63, 156.35 (CF3CO), 160.92 (C-4), 168.98
(CH3CO), 169.82 (CH3CO), 170.69 (CH3CO). Anal. Calcd
for C20H23F3N2O9: C, 48.78; H, 4.71; N, 5.69. Found: C,
48.63; H, 4.67; N, 5.52.
(23) Data for N-[4-Methoxy-2-(2,3,5-tri-O-acetyl-b-D-ribo-
furanosyl)methylpyridin-3-yl]trifluoroacetamide (18):
yield: 34%; light yellow oil; [a]D –30.2° (c = 0.227, CH2Cl2).
1H NMR (CDCl3): d = 1.98 (s, 3 H, CH3CO), 2.03 (s, 3 H,
CH3CO), 2.07 (s, 3 H, CH3CO), 3.03 (m, 1 H, CH2), 3.22 (m,
1 H, CH2), 3.89 (s, 3 H, CH3O), 4.00 (m, 1 H, H-5¢), 4.10 (m,
1 H, H-5¢), 4.33 (m, 1 H, H-4¢), 4.37 (m, 1 H, H-1¢), 4.89 (m,
1 H, H-2¢), 4.96 (m, 1 H, H-3¢), 6.82 (d, J5,6 = 5.86 Hz, 1 H,
H-5), 8.40 (d, J6,5 = 5.86 Hz, 1 H, H-6), 8.71 (br s, D2O exch.,
1 H, NH). 13C NMR (CDCl3): d = 20.49 (CH3CO), 20.58
(CH3CO), 20.64 (CH3CO), 36.77 (CH2), 56.21 (CH3O),
63.56 (C-5¢), 71.32 (C-2¢), 72.47 (C-3¢), 80.79 (C-1¢), 80.98
(C-4¢), 106.46 (C-5), 106.60, 112.33, 118.07, 123.82
(CF3CO), 119.98 (C-3), 150.35 (C-6), 154.40 (C-2), 154.51,
155.22, 155.98, 156.64 (CF3CO), 161.11 (C-4), 169.87 (2 ×
CH3CO), 170.62 (CH3CO). Anal. Calcd for C20H23F3N2O9:
C, 48.78; H, 4.71; N, 5.69. Found: C, 48.92; H, 4.64; N, 5.76.
(24) Marakos, P.; Pouli, N.; Wise, S. D.; Townsend, L. B. Synlett
1997, 561.
C35H33F3N2O6: C, 66.24; H, 5.24; N, 4.41. Found: C, 66.02;
H, 5.31; N, 4.29.
(21) Data for (Z)-N-[4-Methoxy-2-(D-ribofuranosyl-
idene)methylpyridin-3-yl]trifluoroacetamide (15): yield:
86%; mp >250 °C (dec.; EtOH). 1H NMR (DMSO-d6): d =
3.63 (m, 2 H, H-5¢), 4.05 (s, 3 H, CH3O), 4.07 (m, 1 H, H-
3¢), 4.53 (m, 1 H, H-4¢), 4.81 (m, 1 H, H-2¢), 5.28–5.46 (br s,
D2O exch., 2 H, 2 × OH), 5.51 (s, 1 H, =CH), 5.77–5.84 (br
s, D2O exch., 1 H, OH), 7.45 (d, J5,6 = 7.09 Hz, 1 H, H-5),
8.17 (br s, D2O exch., 1 H, NH), 8.64 (d, J6,5 = 7.09 Hz, 1 H,
H-6). 13C NMR (DMSO-d6): d = 57.52 (CH3O), 60.33 (C-5¢),
69.71 (C-3¢), 73.46 (C-2¢), 74.07 (C-1¢), 84.71 (=CH), 93.15
(C-4¢), 104.41 (C-5), 107.45, 113.18, 118.91, 124.65
(CF3CO), 116.28 (C-3), 143.80 (C-6), 148.17 (C-2), 153.94,
154.65, 155.40, 156.12 (CF3CO), 166.92 (C-4). Anal. Calcd
for C14H15F3N2O6: C, 46.16; H, 4.15; N, 7.69. Found: C,
46.22; H, 3.96; N, 7.51.
(22) Data for N-[4-Methoxy-2-(2,3,5-tri-O-acetyl-a-D-
ribofuranosyl)methylpyridin-3-yl]trifluoroacetamide (17).
Yield: 51%; light yellow oil; [a]D +33.1° (c = 0.124,
CH2Cl2). 1H NMR (CDCl3): d = 2.03 (s, 3 H, CH3CO), 2.05
(s, 3 H, CH3CO), 2.12 (s, 3 H, CH3CO), 2.88 (m, 1 H, CH2),
3.17 (m, 1 H, CH2), 3.90 (s, 3 H, CH3O), 4.03 (m, 1 H, H-5¢),
4.24 (m, 1 H, H-5¢), 4.30 (m, 1 H, H-4¢), 4.54 (m, 1 H, H-1¢),
5.26 (m, 1 H, H-3¢), 5.55 (m, 1 H, H-2¢), 6.81 (d, J5,6 = 5.86
Hz, 1 H, H-5), 8.38 (d, J6,5 = 5.86 Hz, 1 H, H-6), 8.84 (br s,
D2O exch., 1 H, NH). 13C NMR (CDCl3): d = 20.57 (2 ×
CH3CO), 20.77 (CH3CO), 35.49 (CH2), 56.22 (CH3O),
63.77 (C-5¢), 72.17 (C-3¢), 72.69 (C-2¢), 77.57 (C-4¢), 80.48
(C-1¢), 106.35 (C-5), 106.51, 112.24, 117.97, 123.71
(25) Data for 1,4-Dihydro-3-(b-D-ribofuranosyl)-7H-pyrazo-
lo[4,3-b]pyridin-7-one(21): yield: 78.9%; mp 200 °C (dec.;
EtOH); [a]D –43.0° (c = 0.330, MeOH). 1H NMR (DMSO-
d6): d = 3.61 (m, 2 H, H-5¢), 3.86 (m, 1 H, H-4¢), 3.94 (m, 1
H, H-3¢), 4.11 (m, 1 H, H-2¢), 4.87 (m, 1 H, H-1¢), 4.93 (br s,
D2O exch., 1 H, OH-3¢), 5.11 (br s, D2O exch., 1 H, OH-2¢),
5.76 (br s, D2O exch., 1 H, OH-5¢) 5.88 (d, J6,5 = 7.14 Hz, 1
H, H-6), 7.59 (d, J5,6 = 7.14 Hz, 1 H, H-5), 11.66 (br s, D2O
exch., 1 H, NH-4), 13.46 (br s, D2O exch., 1 H, NH-1). 13
C
NMR (DMSO-d6): d = 61.27 (C-5¢), 71.58 (C-3¢), 75.33 (C-
2¢), 79.09 (C-1¢), 84.71 (C-4¢), 109.10 (C-6), 126.00 (C-3a),
133.50 (C-7a), 137.23 (C-5), 138.20 (C-3), 168.20 (C-7).
Anal. Calcd for C11H13N3O5: C, 49.44; H, 4.90; N, 15.72.
Found: C, 49.27; H, 4.73; N, 15.59.
(26) (a) Olah, G. A.; Narang, S. C.; Gupta, B. G. B.; Malhotra, R.
J. Org. Chem. 1979, 44, 1247. (b) Ramasany, K.; Imamura,
N.; Robins, R. K.; Revankar, G. R. J. Heterocycl. Chem.
1988, 25, 1893.
Synlett 2008, No. 2, 181–184 © Thieme Stuttgart · New York