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Helvetica Chimica Acta ± Vol. 83 (2000)
CH2CH2CN); 63.1, 63.1 (2t, C(5')); 73.4 (dd, J(C,P) 16.5, C(3')); 73.9 (dd, J(C,P) 18.1, C(3')); 86.0
(dd, J(C,P) 6.9, C(4')); 86.3 (dd, J(C,P) 4.0, C(4')); 86.3, 86.4 (2d, C(1')); 86.7, 86.7 (2s, Ar2C(Ph)); 113.2
(d, arom. C); 117.4, 117.6 (2s, CN); 121.0, 121.0 (2s, C(5)); 127.0, 127.0, 127.9, 128.0, 129.9, 130.0, 130.0
(7d, arom. C); 135.3, 135.3 (2s, arom. C); 142.3, 142.4 (2d, C(6)); 144.2 (s, arom. C); 146.1, 146.2 (2s, C(8));
153.7, 153.8 (2s, C(2)); 158.6, 158.6 (2s, arom. C); 162.4 (s, C(4)); 171.6, 171.9 (2s, CO). 31P-NMR (81 MHz,
CDCl3): 148.6, 148.8.
N-[6-Chloro-9-(3',5'-di-O-acetyl-2'-deoxy-a,b-d-ribofuranosyl)-9H-purin-2-yl]acetamide (a/b-d-8). To a
suspension of 1 (1 g, 4.8 mmol) in abs. MeCN (20 ml), BSA (2.3 ml, 9.5mmol, 2 equiv.) was added and the
resulting soln. stirred at 608 for 1 h. After the addition of 2 (1.3 g, 5.6 mmol, 1.2 equiv.) and Me3SiOSO2CF3
(1.7 ml, 9.5mmol, 2 equiv.), the soln. was stirred at 60 8 for 3 h. The mixture was diluted in CH2Cl2 (200 ml) and
washed with sat. NaCl (100 ml), sat. NaHCO3 (100 ml), and sat. NaCl soln.(100 ml), the combined org. phase
dried (Na2SO4) and evaporated, and the residue (1.6 g) purified by FC (silica gel (100 g), AcOEt/hexane 20 :1):
a/b-d-8 (790 mg, 40%). TLC (CH2Cl2/MeOH 20 :1): Rf 0.42. 1H-NMR (300 MHz, CDCl3): 1.98, 2.05, 2.11, 2.13
(4s, 2 AcO); 2.51 (s, AcN); 2.58 ± 2.66, 2.69 ± 2.76, 2.87 ± 2.98 (3m, 2 HÀC(2')); 4.21 ± 4.28, 4.37 ± 4.41 (2m,
2 HÀC(5')); 4.35, 4.62 (m, dt, J 2.1, 4.3, HÀC(4')); 5.32, 5.44 (2m, HÀC(3')); 6.36, 6.47 (dd, J 6.1, 7.4, dd, J
2.0, 7.2, HÀC(1')); 8.05(br., NH); 8.14, 8.25(2 s, HÀC(8)). 13C-NMR (75MHz, CDCl 3): 20.7, 20.8
(2q, MeCOO); 25.0, 25.1 (2q, MeCON); 37.3, 37.9 (2t, C(2')); 63.5, 63.6 (2t, C(5')); 74.1 (d, C(3')); 82.7, 85.0
(2d, C(1')); 84.2, 85.5 (2d, C(4')); 128.3, 128.6 (2s, C(5)); 142.4, 142.7 (2d, C(8)); 143.9, 144.1 (2s, C(4)); 151.4
(s, C(6)); 151.9, 152.0 (2s, C(2)); 169.9, 170.2, 170.3 (3s, CO).
N-[9-(3',5'-Di-O-acetyl-2'-deoxy-a/b-d-ribofuranosyl-9H-purin-2-yl]acetamide (a/b-d-9). To a soln. of a/b-
d-8 (430 mg, 1.05mmol) in MeOH (15ml), Et 3N (175 ml, 1.25 mmol) and 10% Pd/C (525 mg, 500 mg/mmol)
were added. The mixture was stirred under H2 for 4 h and then filtered through Celite, the filtrate evaporated,
and the residue (520 mg) purified by FC (silica gel (25 g), CH2Cl2/MeOH 20 :1): a/b-d-9 (286 mg, 73%). TLC
(CH2Cl2/MeOH 10 :1): Rf 0.55. 1H-NMR (300 MHz, CDCl3): 1.97, 2.05, 2.10, 2.12 (4s, 2AcO); 2.46, 2.52
(2s, AcN); 2.58 ± 2.65, 2.70 ± 2.79, 2.88 ± 3.02 (3m, 2 HÀC(2')); 4.24 ± 4.44, 4.6 (2m, 2 HÀC(5'), HÀC(4')); 5.32,
5.44 (dt, J 2.1, 7.7, m, HÀC(3')); 6.39, 6.51 (dd, J 6.2, 7.7, dd, J 2.2, 7.1, HÀC(1')); 8.11, 8.23 (2s, HÀC(8));
8.53 (br. s, NH); 8.94, 8.96 (2s, HÀC(6)). 13C-NMR (75MHz, CDCl 3): 20.8, 20.8, 20.9 (3q, MeCOO); 25.1, 25.2
(2q, MeCN); 37.1, 37.8 (2t, C(2')); 63.6, 63.6 (2t, C(5')); 74.2, 74.3 (2d, C(3')); 82.6, 84.0, (2d, C(1')); 84.6, 85.0
(2d, C(4')); 131.0, 131.3 (2s, C(5)); 142.5, 142.8 (2d, C(8)); 149.7, 149.9 (2d, C(6)); 151.6 (C(4)); 152.9, 153.0
(2s, C(2)); 170.0, 170.2, 170.4, 170.5(4 s, CO). HR-LSI-MS: 378.14154 (C16H20N5O6 , [M H] ; calc.
378.14136).
N-[9-(2'-Deoxy-a,b-d-ribofuranosyl)-9H-purin-2-yl]acetamide (a/b-d-10). As described for a/b-d-5, from
a/b-d-9 (244 mg, 0.65mmol): a/b-d-10 (189 mg, 99%), which was used without further purification. TLC
(CH2Cl2/MeOH 5:1): Rf 0.54. 1H-NMR (300 MHz, CD3OD): 2.34 (s, AcN); 2.54, 2.89 (2m, 2 HÀC(2')); 3.70 ±
3.85( m, 2 HÀC(5')); 4.06, 4.41 ± 4.68 (2m, HÀC(3'), HÀC(4')); 6.59 (m, HÀC(1')); 8.59 (br. NH); 8.69, 8.73
(2s, HÀC(8)); 8.94 (s, HÀC(6)). 13C-NMR (75MHz, CD 3OD): 25.0 (q, MeCON); 41.4, 41.5(2 t, C(2')); 63.3,
63.6 (2t, C(5')); 72.5, 73.0 (2d, C(3')); 85.9, 86.6 (2d, C(1')); 89.6, 90.7 (2d, C(4')); 132.2 (s, C(5)); 146.3, 146.8
(2d, C(8)); 149.9, 150.0 (2d, C(6)); 153.1 (s, C(2)); 154.3 (C(4)); 172.5, 172.7 (2s, CO).
N-{9-{5'-O-[Bis(4-methoxyphenyl)phenylmethyl]-2'-deoxy-a/b-d-ribofuranosyl}-9H-purin-2-yl}acetamide
(a/b-d-11). As described for a/b-d-6; from a/b-d-10 (131 mg, 0.45mmol), in abs. Py (15ml), and (MeO) 2TrCl
(195mg, 0.58 mmol, 1.3 equiv.), after two FCs (CH 2Cl2/MeOH 20 :1): a-d-11 (100 mg, 38%) and b-d-11 (66 mg,
25%) as slightly yellow foams.
Data of a-d-11: TLC (CH2Cl2/MeOH 20 :1): Rf 0.16. 1H-NMR (300 MHz, CDCl3): 2.33 (s, AcN); 2.75, 3.05
(2m, 2 HÀC(2')); 3.21, 3.35(2 m, 2 HÀC(5')); 3.76 (s, 2 MeO); 4.49 (m, HÀC(3')); 4.54 (m, HÀC(4')); 4.90
(br., OHÀC(3')); 6.30 (dd, J 2.8, 8.7, HÀC(1')); 6.81 (d, J 8.9, 4 arom. H); 7.19 ± 7.42 (m, 9 arom. H); 8.19
(s, HÀC(8)); 8.66 (br. s, NH); 8.93 (s, HÀC(6)). 13C-NMR (75MHz, CDCl 3): 25.0 (q, MeCN); 40.3 (t, C(2'));
55.2 (q, MeO); 64.3 (t, C(5')); 73.1 (d, C(3')); 86.3 (d, C(1')); 88.0 (d, C(4')); 113.2 (d, arom. C); 126.7, 127.9,
128.1, 130.0 (4d, arom. C); 132.0 (s, C(5)); 135.8, 135.9 (2s, arom. C); 144.7 (s, arom. C); 145.3 (d, C(8)); 149.8
(d, C(6)); 151.3 (s, C(2)); 152.2 (s, C(4)); 158.6 (s, arom. C). HR-LSI-MS 596.25092 (C33H34NO6 , [M H] ;
calc. 596.25091).
Data of b-d-11: TLC (CH2Cl2/MeOH 20 :1): Rf 0.14. 1H-NMR (300 MHz, CDCl3): 2.43 (s, MeCON); 2.64
(m, 2 HÀC(2')); 3.37 (m, 2 HÀC(5')); 3.71 (s, 2 MeO); 4.27 (m, HÀC(4')); 4.74 (m, HÀC(3')); 6.63
(m, HÀC(1')); 6.72 ± 6.80 (d, J 8.6, 4 arom. H); 7.11 ± 7.27 (m, 7 arom. H); 7.34 ± 7.36 (d, J 7.4, 2 arom. H);
8.17 (s, HÀC(8)); 9.10 (s, HÀC(6)); 10.23 (br. s, NH). 13C-NMR (75MHz, CDCl 3): 25.0 (q, MeCON); 40.9
(t, C(2')); 55.2 (q, MeO); 64.0 (t, C(5')); 72.5( d, C(3')); 84.5( d, C(1')); 86.6 (d, C(4')); 113.1 (d, arom. C); 126.9,
127.8, 128.1, 130.0 (4d, arom. C); 131.0 (s, C(5)); 135.6, 135.6 (2s, arom. C); 143.1 (d, C(8)); 144.5( s, arom. C);