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Helvetica Chimica Acta ± Vol. 81 (1998)
H
C(1')); 7.30 ± 7.96 (arom. H); 8.59 (s, H C(2)); 8.81 (s, H C(8)). Anal. calc. for C29H30N4O6 (530.58):
C 65.65, H 5.70, N 10.56; found: C 65.71, H 5.88, N 10.69.
9-[2-Deoxy-3,5-di-O-(4-toluoyl)-b-d-erythro-pentofuranosyl]-6-isopropoxy-9H-purine (6d): Colorless
foam (1.01 g, 38%). TLC (H): Rf 0.6. UV (MeOH): 241 (42400). 1H-NMR ((D6)DMSO): 1.41, 1.42
(d, Me2CHO); 2.39, 2.42 (2s, 2 Me); 2.82 (m, Hb C(2')); 3.42 (m, Ha C(2')); 4.58 (m, 2H C(5')); 4.68
(m, H C(4')); 5.60 (m, Me2CHO); 5.87 (m, H C(3')); 6.63 (ꢀtꢀ, J 6.8, H C(1')); 7.30 ± 7.98 (arom. H); 8.48
(s, H C(2)); 8.58 (s, H C(8)). Anal. calc. for C29H30N4O6 (530.58): C 65.65, H 5.70, N 10.56; found: C 65.82,
H 5.81, N 10.44.
7-[2-Deoxy-3,5-di-O-(4-toluoyl)-b-d-erythro-pentofuranosyl]-6-isopropoxy-7H-purine (7d): Colorless
foam (850 mg, 32%). TLC (H): Rf 0.2. UV (MeOH): 240 (38000). 1H-NMR ((D6)DMSO): 1.41 (d, Me2CHO);
2.35, 2.40 (2s, 2 Me); 2.83 (m, Hb C(2')); 2.95 (m, Ha C(2')); 4.59 ± 4.65 (m, H C(4'), 2 H C(5')); 5.53
(m, Me2CHO); 5.70 (m, H C(3')); 6.69 (ꢀtꢁ, J 6.5, H C(1')); 7.26 ± 7.94 (arom. H); 8.56 (s, H C(2)); 8.75
(s, H C(8)). Anal. calc. for C29H30N4O6 (530.58): C 65.65, H 5.70, N 10.56; found: C 65.77, H 5.70, N 10.43.
9-[2-Deoxy-3,5-di-O-(4-toluoyl)-b-d-erythro-pentofuranosyl]-6-isobutoxy-9H-purine (6e): Colorless foam
(1.16 g, 43%). TLC (H): Rf 0.6. UV (MeOH): 241 (42500). 1H-NMR ((D6)DMSO): 1.00 (d, Me2CH); 2.10
(m, Me2CH); 2.39, 2.42 (2s, 2 Me); 2.82 (m, Hb C(2')); 3.42 (m, Ha C(2')); 4.40 (m, CH2O); 4.58
(m, 2 H C(5')); 4.68 (m, H C(4')); 5.87 (m, H C(3')); 6.63 (ꢀtꢁ, J 6.8, H C(1')); 7.30 ± 7.98 (arom. H);
8.46 (s, H C(2)); 8.55 (s, H C(8)). Anal. calc. for C30H32N4O6 (544.60): C 66.16, H 5.92, N 10.29; found:
C 66.12, H 5.89, N 10.26.
7-[2-Deoxy-3,5-di-O-(4-toluoyl)-b-d-erythro-pentofuranosyl]-6-isobutoxy-7H-purine (7e): Colorless foam
1
(762 mg, 28%). TLC (H): Rf 0.2. UV (MeOH): 240 (38000). H-NMR ((D6)DMSO): 0.99 (d, Me2CH); 2.08
(m, Me2CH); 2.36, 2.40 (2s, 2 Me); 2.85 (m, Hb C(2')); 2.95 (m, Ha C(2')); 4.31 (m, CH2O); 4.57 ± 4.64
(m, H C(4'), 2 H C(5')); 5.70 (m, H C(3')); 6.71 (ꢀtꢁ, J 6.5,
H C(1')); 7.28 ± 7.94 (arom. H); 8.56
(s, H C(2)); 8.81 (s, H C(8)). Anal. calc. for C30H32N4O6 (544.60): C 66.16, H 5.92, N 10.29; found: C 66.12,
H 5.94, N 10.36.
General Deprotection Procedure. Compound 6 or 7 (1.0 mmol) was dissolved in 0.1m NaOMe/MeOH
(20 ml) and stirred for 30 min at r.t. The mixture was adsorbed on silica gel (10 g) and applied to FC (silica gel;
column 10 Â 5 cm, B (300 ml), then C): 8 or 9, resp.
9-(2-Deoxy-b-d-erythro-pentofuranosyl)-6-ethoxy-9H-purine (8b): Colorless foam (240 mg, 85%). TLC
(C): Rf 0.5. UV (MeOH): 249 (10500). 1H-NMR ((D6)DMSO): 1.38 (t, J 7.0, MeCH2O); 2.32 (m, Hb C(2'));
2.73 (m, Ha C(2')); 3.56 (m, 2 H C(5')); 3.87 (m, H C(4')); 4.41 (m, H C(3')); 4.56 (q, J 7.0, MeCH2O);
4.59 (t, J 5.5, OH C(5')); 5.29 (d, J 4.0, OH C(3')); 6.41 (ꢀtꢁ, J 6.8, H C(1')); 8.48 (s, H C(2));8.55
(s, H C(8)). Anal. calc. for C12H16N4O4 (280.28): C 51.42, H 5.75, N 19.99; found: C 51.56, H 5.85, N 19.86.
7-(2-Deoxy-b-d-erythro-pentofuranosyl)-6-ethoxy-7H-purine (9b): Colorless foam (230 mg, 81%). TLC
(C): Rf 0.3. UV (MeOH): 259 (8000). 1H-NMR ((D6)DMSO): 1.42 (t, J 7.0, MeCH2O); 2.42 (m, Hb C(2'));
2.54 (m, Ha C(2')); 3.60 (m, 2 H C(5')); 3.91 (m, H C(4')); 4.37 (m, H C(3')); 4.56 (m, MeCH2O); 4.65
(t, J 5.5, OH C(5')); 5.32 (d, J 4.0, OH C(3')); 6.51 (ꢀtꢁ, J 6.1, H C(1')); 8.54 (s, H C(2)); 8.80
(s, H C(8)). Anal. calc. for C12H16N4O4 (280.28): C 51.42, H 5.75, N 19.99; found: C 51.46, H 5.73, N 19.96.
9-(2-Deoxy-b-d-erythro-pentofuranosyl)-6-propoxy-9H-purine (8c): Colorless foam (241 mg, 82%). TLC
(C): Rf 0.5. UV (MeOH): 249 (10700). 1H-NMR ((D6)DMSO): 0.98 (t, J 7.3, MeCH2CH2O); 1.78
(m, MeCH2CH2O); 2.23 (m, Hb C(2')); 2.61 (m, Ha C(2')); 3.55 (m, 2 H C(5')); 3.85 (m, H C(4')); 4.37
(m, MeCH2CH2O); 4.37 (m, H C(3')); 5.0 (t, J 5.4, OH C(5')); 5.26 (d, J 3.7, OH C(3')); 6.23 (ꢀtꢁ, J
7.3, H C(1')); 8.50 (s, H C(2)); 8.57 (s, H C(8)).
7-(2-Deoxy-b-d-erythro-pentofuranosyl)-6-propoxy-7H-purine (9c): Colorless foam (247 mg, 84%). TLC
(C): Rf 0.3. UV (MeOH): 259 (7200). 1H-NMR ((D6)DMSO): 1.01 (t, J 7.3, MeCH2CH2O); 1.80
(m, MeCH2CH2O); 2.32 (m, Hb C(2')); 2.54 (m, Ha C(2')); 3.56 (m, 2 H C(5')); 3.86 (m, H C(4')); 4.34
(m, H C(3')); 4.35 (t, J 6.3, MeCH2CH2O); 5.03 (t, J 5.2, OH C(5')); 5.27 (d, J 4.1, OH C(3')); 6.50
(ꢀtꢁ, J 6.1, H C(1')); 8.52 (s, H C(2)); 8.80 (s, H C(8)).
9-(2-Deoxy-b-d-erythro-pentofuranosyl)-6-isopropoxy-9H-purine (8d): Colorless foam (250 mg, 85%).
TLC (C): Rf 0.5. UV (MeOH): 250 (10700). 1H-NMR ((D6)DMSO): 1.41 (d, Me2CHO); 2.33 (m, Hb C(2'));
2.75 (m, Ha C(2')); 3.60 (m, 2 H C(5')); 3.91 (m, H C(4')); 4.45 (m, H C(3')); 5.01 (t, J 5.0, OH C(5'));
5.32 (d, J 3.7, OH C(3')); 5.60 (m, Me2CHO); 6.44 (ꢀtꢁ, J 6.4,
H C(1')); 8.51 (s, H C(2)); 8.57
(s, H C(8)). Anal. calc. for C13H18N4O4 (294.31): C 53.05, H 6.16, N 19.04; found: C 53.19, H 6.08, N 18.98.
7-(2-Deoxy-b-d-erythro-pentofuranosyl)-6-isopropoxy-7H-purine (9d): Colorless foam (244 mg, 83%).
1
TLC (C): Rf 0.3. UV (MeOH): 259 (7400). H-NMR ((D6)DMSO): 1.41 (d, Me2CHO); 2.42 (m, Hb C(2'));
2.48 (m, Ha C(2')); 3.62 (m, 2 H C(5')); 3.91 (m, H C(4')); 4.36 (m, H C(3')); 5.03 (t, J 5.3, OH C(5'));