ORDER
REPRINTS
924
SERAFINOWSKI, BROWN, AND BARNES
fewer changes in the standard protocol and resulted in (2ꢀ–5ꢀ) and (3ꢀ–5ꢀ) linked
oligonucleotides modified with 3ꢀ- or 2ꢀ-difluoromethyl groups.
ACKNOWLEDGMENTS
These investigations were supported by the Cancer Research Campaign.
REFERENCES
1. Cook, P.D. Annual Reports in Medicinal Chemistry 1999, 33, 313–325.
2. Schmit, C.; Be´viere, M.O.; De Mesmaeker, A.; Altman, K.H. Bioorg. & Med. Chem
Lett. 1994, 4, 1969–1976.
3. Schmit, C. Synlett. 1994, 241–242.
4. Serafinowski, P.J.; Barnes, C.L. Tetrahedron. 1996, 52 (23), 7929–7938.
5. Serafinowski, P.J.; Barnes, C.L. Synthesis. 1997, 225–228.
6. Serafinowski, P.J.; Brown, C.A. Tetrahedron. 2000, 56 (4), 333–339.
7. All the NMR spectra were recorded in DMSO-d6 and UV spectra in 95% EtOH. 3a
NMR δH 3.02 (m, 1H, H-2ꢀ), 3.63 (m, 3H, H-4ꢀ, H-5ꢀ, H-5ꢀꢀ), 4. 33 (t, 1H, H-3ꢀ J =
7.69 Hz), 4.95 (bs, 1H, 5ꢀ -OH), 5.61 (d, 1H, H-6, J = 8.12 Hz), 5.83 (d, 1H, 3ꢀ -OH,
J = 7.25 Hz), 6.02 (t of d, 1H, CF2H, JHF = 45.6 Hz, JHH = 4.47 Hz ), 6.21 (d, 1H, H-1ꢀ,
J = 7.75 Hz) 7.84 (d, 1H, H-6, J =8.12 Hz), 11.41 (bs, 1H, NH); δC 51.60 (t, JC-F
=
19 Hz, C-2ꢀ), 57.96 (C-5ꢀ), 66.31 (C-3ꢀ), 81.04 (C-1ꢀ), 83.84 (C-4ꢀ), 100.44 (C-5),
114.54(t, JC-F =240Hz, CF2H), 140.18(C-6), 149.31(C-2), 162.13(C-4);δF −117.17
(1F, d (JFF = 292 Hz) of d (JHgem-F = 54.6 Hz), −121.46 (1F, d (JFF = 292 Hz) of d
(JHgem-F = 53.53 Hz); UV λmax 259 nm εmax 6468, λmin 229 nm εmin 1564; Observed
FAB MS 279.0770, [C10H12F2N2O5 + H]+ requires 279.0793. 3b NMR δH 2.89
(m, 1H, H-2ꢀ), 3.59 (m, 2H, H-5ꢀ, H-5ꢀꢀ), 3.85 (m, 1H, H-4ꢀ), 4. 36 (d, 1H,-3ꢀ, J =
4.48 Hz), 5.12 (bs, 1H, 5ꢀ-OH), 5.69 (d, 1H, H-5, J = 8.13 Hz), 5.79 (bs, 1H, 3ꢀ-
OH), 6.33 (d, 1H, H-1ꢀ, J = 8.53 Hz), 6.19 (t of d, 1H, CF2H, JHF = 55.4 Hz, JHH
=
=
6.80 Hz), 7.85 (d, 1H, H-6, J = 8.13 Hz), 11.32 (bs, 1H, NH); δF −114.58 (1F, d (JFF
ꢀ
295 Hz) of q (JHgem-F = 54.1 Hz, JH2 -F = 10.0 Hz), −123.51 (1F d (JFF = 295 Hz)
ꢀ
of q (JHgem-F = 55.9 Hz, JH2 -F = 14.3 Hz); UV λmax 260 nm εmax 7426, λmin 230 nm
εmin 1098; Observed FAB MS 279.0702, [C10H12F2N2O5+ H]+requires 279.0793. 6a
NMR δH2.87 (m, 1H, H-3ꢀ), 3. 57 (m, 2H, H-5ꢀ, H-5ꢀꢀ), 4.30 (m, 2H, H-2ꢀ, H-4ꢀ),
5.32 (bs, 1H, 5ꢀ-OH), 5.71(m, 3H, H-1ꢀ, 2ꢀ-OH, H-5), 6.31 (t of d, 1H, CF2H, JHF
=
49.08 Hz, JHH = 6.88 Hz ), 7.84 (d, 1H, H-6, J = 8.16 Hz), 11.34 (bs, 1H, NHi); ); δC
C-2ꢀ), 49.38 (t, JC-F = 19.5 Hz, C-3ꢀ), 60.58 (C-5ꢀ), 76.90 (C-4ꢀ), 87.96 (C-1ꢀ), 102.40
(C-5), 116.96 (t, JC-F = 251 Hz, CF2H), 140.69 (C-6), 150.92 (C-2), 163.03 (C-4); δF
ꢀ
−112.08 1F d (JFF = 294 Hz) of q (JHgem-F = 55.55 Hz, JH-3 -F = 11.57 Hz), −116.75
1F d (JFF = 294 Hz) of q (JHgem = 56.3 Hz, JH-3-F = 15.08 Hz); UV λmax 260 nm
F
εmin 8778 λmin 229 nm εmin 3436; Observed ES MS 279.0802, [C10H12F2N2O5 + H]+
requires 279.0793. 6b NMR δH 2.73 (m, 1H, H-3ꢀ), 3.52 (m, 1H, H-5ꢀ), 3.75 (m, 1H,
H-5ꢀꢀ), 4. 34 (m, 3H, H-2ꢀ, H-4ꢀ, 5ꢀ-OH), 5.61 ( d, 1H, J = 8.24 Hz, H-5), 5.68 (bs, 2H,
3ꢀ-OH, H-1ꢀ), 6.20 (t , JHF = 56.1 Hz of d JHH = 5.28 Hz, 1H, CF2H), 7.98 (d, 1H, H-6,
J = 8.24 Hz), 11.30 (bs, 1H, NH); δF −116.03 1F d (JFF = 290 Hz) of q (JHgem-F
=