U. Eilitz et al. / Journal of Fluorine Chemistry 115 (2002) 149±154
153
a 70 (c 4, CHCl ); IR (KBr) n 2987, 2878, 1786,
evaporation of the solvent 0.036 g (70%) of 11 were
obtained as a colorless oil.
D
3
1711, 1455, 1383, 1367, 1257, 1215, 1190 cmÀ1; H NMR
1
(CDCl3): d 1.40 [s, 3H, C(CH3)2], 1.61 [s, 3H, C(CH3)2], 3.50
a 2:1 (c 0:42, MeOH). IR (Nujol) n 1451, 1413,
D
1340, 1247, 1149, 1084, 1041 cmÀ1; MS, EI ꢀm=z 332
2
3
(s, 1H, OH-2), 4.00 (dd, 1H, J5a=5b 12:9 Hz, J5a=4
2
3
3:2 Hz, H-5a), 4.09 (dd, 1H, J5a=5b 12:9 Hz, J5b=4
(M À 2H2O), 303 (M À OH À CH2OH), 291 (M À
3
3
1:6 Hz, H-5b), 4.33 (ddd, 1H, J4=3 6:8 Hz, J4=5a
HCOOH À CH2OH), 97 (C5H7O2) , 55 (C3H3O) , 41
3:2 Hz, J 1:6 Hz, H-4), 4.52 (d, 1H, 2J 11:6 Hz,
(C2HO) .
CH2a), 4.64 (d, 1H, J3=4 6:8 Hz, H-3), 4.72 (d, 2J
3
11:6 Hz, CH2b), 5.19 (s, 1H, H-1), 7.26±7.36 (m, 5H, Ph);
13C NMR(CDCl3): d 25.0 (CH3), 26.4 (CH3), 58.3 (C-5), 69.0
3.3. Relative amounts of tautomeric forms at equilibrium
in D6-acetone
3
3
(d, JCF 1:8 Hz, C-3), 69.1 (d, JCF 1:8 Hz, C-3), 70.9
(CH2), 71.2 (C-4), 72.3 (td, 2J 22:1 Hz, 3JCF 2:0 Hz, C-
2), 97.4 (t, 3JCF 1:6 Hz, C-1), 109.8 (CMe2), 111.2±126.4
(C4F9), 128.4 (C-4, Ph), 128.6 (C-2, 6, h), 129.0 (C-3, 5, Ph),
136.7 (C-1, Ph). 19F NMR (CDCl3): d À48.74, À48.18,
À44.01, À43.25, À41.61 (m, 4F, CF2CF2), À40.17 (dm, 1F,
2J 295:5 Hz, CF2), À37.13 (dm, 1F, 2J 297:6 Hz, CF2),
3.3.1. a-Furanose (80%)
1
2
3
H NMR: d 3.68 (dd, 1H, J 12:7 Hz, J4=5 4:5 Hz,
H-5) 3.86 (mÃ, H-4), 3.87 (dÃ, 2J 12:7 Hz, H-5), 4.34 (d,
1H, J3=4 8:0 Hz, H-3), 5.52 (s, 1H, H-1); 13C NMR: d
3
60.6 (C-5), 69.9 (C-3), 80.9 (C-4), 95.5 (C-1), C-2 could not
be extracted because of low intensity; 19F NMR: d À49.33
(dm, 1F, 2J 292 Hz, CF2), À47.37 (dm, 1F, 2J 293 Hz,
À3.05 (m, 3F, CF3); MS, EI (m/z): 483 (M À Me), 407
2
(M À Bn), 349 (M À Bn À acetone), 319 (M À BnÀ
CF2), À43.51 (m, 2F, CF2), À44.30 (dm, 1F, J 298 Hz,
acetone À CH2O), 303 (M À OBn À acetone À CH2O),
CF2), À41.98 (dm, 2J 298 Hz, CF2), À3.25 (m, 3F, CF3).
219 (C4F9) , 91 (C7H7) , 59 (C3H7O) , 43 (C2H3O) . Anal.
Found:C,45.69;H,3.76%.Calcd.forC19H19F9O5(498.36):C,
45.79; H, 3.84%.
3.3.2. b-Furanose (11%)
1H NMR:
d
3.77 (ddÃ, 1H, J5a=5b 12:6 Hz,
2
3J5a=4 1:7 Hz, H-5a), 3.98 (ddÃ, 1H, J5a=b 12:6 Hz,
3J5b=4 1:2 Hz, H-5b), 4.00 (mÃ, 1H, H-4), 4.10 (sÃ, 1H,
H-3), 4.89 (s, 1H, H-1); 19F NMR: d À49.05 (dm, 1F,
2J 292 Hz, CF2), À46.35 (dm, 1F, 2J 292 Hz, CF2),
À42.97 (dm, 1F, 2J 296 Hz, CF2), À40.04 (dm, 1F,
2J 299 Hz, CF2), À38.68 (dm, 1F, 2J 292 Hz, CF2),
2
3.2.5. ()-Benzyl-2-C-perfluorobutyl-b-L-ribopyranoside
(9)
Benzyl-3,4-O-isopropylidene-2-C-per¯uorobutyl-b-L-
ribopyranoside (8) (0.145 g, 0.3 mmol) and 60% AcOH
(5 ml) were stirred at 40±50 8C for 24 h. After evaporation
of the solvent, the remaining residue was puri®ed by crystal-
lization from THF/hexanes to give 0.12 g (90%) 9, mp: 147±
149 8C (colorless crystals).
Ã
2
À36.38 (dm, 1F, J 293 Hz, CF2), À3.25 (m , 3F, CF3).
3.3.3. a-Pyranose (<1%), b-Pyranose (9%)
a 67:4 (c 0:46, acetone); IR (KBr) n 3343, 1343,
1HNMR:d3.23(dd,1H,2J5a=5b 8:6 Hz,3J5a=4 6:1 Hz,
H-5a),3.57(dd,1H,2J5a=5b 8:6 Hz,3J5b=4 6:1 Hz,H-5b),
4.35 (sÃ, 1H, H-3), 5.33 (sÃ, 1H, H-1), H-4 could not be
extracted; 19F NMR: d À 49:5 (dmÃ, 1F, CF2), À46.35
(dmÃ, 1F, CF2), À41.93 (dm, 1F, 2J 291 Hz, CF2),
À41.18 (dm, 1F, 2J 294 Hz, CF2), À37.80 (dm, 1F,
2J 291 Hz, CF2), À35.08 (dm, 1F, 2J 295 Hz, CF2),
À3.25 (mÃ, 3F, CF3); (Ã Resonance signals are overlapping).
D
1267, 1201, 1183, 1145, 1099, 1061 cmÀ1; 1H NMR(CDCl3):
2
3
d 3.83 (dd, 1H, J5a=5b 12:6 Hz, J5a=4 1:4 Hz, H-5a),
4.05(d, 1H, 2J5a=5b 12:6 Hz, H-5b), 4.13(m, 1H, H-4), 4.24
(d, 1H, 3J3=4 3 Hz, H-3), 4.58 (d, 1H, 2J 11:6 Hz, CH2a),
4.81(d,1H,2J 11:6 Hz,CH2b),5.11(s,1H,H-1),7.36±7.42
(m, 5H, Ph); 13C NMR (CDCl3): d 63.5 (C-5), 64.7 (C-3), 70.0
(CH2), 71.3 (C-4), 79.5 (t, 2JCF 22:1 Hz, C-2), 99.9 (C-1),
110±126(C4F9),128.2(C-2,4,6,Ph),128.8(C-3,5,Ph),137.8
(C-1, Ph); 19F NMR (CDCl3): d À48.58 (dm, 1F, 2J
291:3 Hz, CF2), À46.21 (dm, 1F, 2J 294:6 Hz, CF2),
À42.99 (dm, 1F, 2J 288:3 Hz, CF2), À40.96 (dm, 1F,
2J 288:5 Hz, CF2), À37.23 (d, 1F, 2J 291:8 Hz),
Acknowledgements
The authors are grateful to the European Community
(TMR: Contract no. ERBFMRXCT 970 120: ``Fluorine:
A Unique Tool for Engineering Molecular Properties''), the
Deutsche Forschungsgemeinschaft and the Fonds der Che-
mischen Industrie for ®nancial support.
2
À34.82 (ddt, 1F, J 294:6 Hz, J 21:5 Hz, J 14 Hz,
CF2), À3.0 (m, 3F, CF3); MS, EI ꢀm=e 351 (M À Bn),
321 (M À Bn À CH2O), 219 (C4F9) , 91 (C7H7), 43
(C2H3O) .
3.2.6. ()-2-C-Perfluorobutyl-L-ribose (11)
A solution of benzyl-2-C-per¯uorobutyl-b-L-ribopyrano-
side (9) (0.07 g, 0.15 mmol) in dry MeOH (5 ml) was stirred
in the presence of a Pd/C catalyst in an atmosphere of
hydrogen until the starting material was completely con-
sumed (4 weeks, 19F NMR analysis). After ®ltration and
References
[1] I. Ojima, J.R. Mc Carthy, J.R. Welch, Biomedical frontiers of
fluorine chemistry, ACS Symposium Series 639 (1996) and literature
cited therein.