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mixture was evaporated several times with water; the residue was suspended in water con-
taining TFA (0.1%) and filtered. The filtrate was applied to a column (2.5 · 15 cm) packed
with Porasil C18 55–105 lm (Waters, Milford, MA, USA). Chromatography was per-
formed with a linear gradient of 300 mL each of 0.1% aqueous TFA and 10% ethanol
in 0.1% aqueous TFA. Appropriate fractions were pooled and evaporated to give 20-azi-
domethylderivative 4d as a white powder (0.25 g, 85%). Rf 0.33 (iPrOH:H2O 4:1); dH
(400 MHz, D2O) 3.40 (1H, dd, J 11.3, 13.0, H50), 3.66 (2H, m, H30, H50), 3.80 (1H, dd,
J 13.2, 3.6, H30), 3.87–3.97 (2H, m, N3CH2–), 4.56 (1H, m, H20), 6.23 (1H, dd, J 10.2,
4.0, H60) 8.34 (1H, s, H8(Gua)); dC (100 MHz, D2O) 46.17, 46.88, 54.27, 76.12, 80.41,
119.25, 139.80, 153.69, 157.84, 160.74. Compound 4d (0.25 g, 0.85 mmol) was suspended
in pyridine (3 mL), and triphenylphosphine (0.39 g, 1.5 mmol) was added to the reaction
mixture. After 2 h of stirring at room temperature, concentrated aqueous ammonia (2 mL)
was added, and the solution was left overnight with stirring. The reaction mixture was
evaporated; the residue was suspended in water containing TFA (0.1%) and filtered.
The filtrate was applied to a column (2.0 · 13 cm) packed with Servacel P-23 (Serva, Hei-
delberg, Germany) in the NHþ4 form. Elution was performed with a linear gradient of
300 mL each of 20% ethanol in water and 0.075 M NH4HCO3 in 20% ethanol in water.
Appropriate fractions were pooled and evaporated. The residue was coevaporated several
times with ethanol to remove traces of ammonium bicarbonate and dried under vacuum.
Compound 8 was obtained as a white powder (0.15 g, 0.46 mmol, yield 54%). Found: C,
40.85, H, 5.55, N, 30.50; calculated for C10H15N7O2+H2CO3: C, 40.4, H, 5.25, N, 29.95;
Rf 0.32 (iPrOH:H2O:conc.ammonia 6:3:1); dH (300 MHz, D2O+2mcL TFA) 2.53 (1H, dd,
J 10.0, 13.0, H50), 2.90 (1H, dd, J 13.0, 2.5, H30), 2.95–3.21 (4H, m, H30,H50, NH2CH2–),
4.06 (1H, m, H20), 5.49 (1H, dd, J 10.0, 3.2, H60), 7.77 (1H, s, H8(Gua)); dC (75.5 MHz,
D2O+2mkl TFA) 40.71, 44.87, 46.72, 73.61, 79.2, 115.58, 145.19, 150.65, 153.86, 158.61;
m/z 266.64 [M+H]+.
2.2.2. 20-Aminomethyl-60-(cytosine-1-yl)- morpholine 7 (Scheme 1)
Compound 7 was synthesized from 1c following exactly the same reaction sequence as
in the case of compound 8. The target product was obtained as a white powder (0.10 g,
0.39 mmol, yield 39% starting from compound 1c). Found: C, 44.2, H, 6.65, N, 27.6; cal-
culated for C9H17N5O2 +1/2H2CO3: C, 44.2, H, 7.0, N, 27.1; Rf 0.37
(iPrOH:H2O:conc.ammonia 6:3:1); dH (300 MHz, D2O) 2.41 (1H, app. t, J 12.1, H50),
2.56 (1H, app. t, J 11.5, H30), 2.64–3.14 (4H, m, H30, H50, NH2CH2–), 3.79 (1H, m,
H20), 5.60 (1H, dd, J 10.0, 2.6, H60), 5.90 (1H, d, J 7.5, H5(Cyt)), 7.63 (1H, d, J 7.5,
H6(Cyt)); dC (100 MHz, D2O) 45.85, 48.56, 50.39, 79.8, 84.45, 99.50, 145.04, 157.02,
169.33; m/z 228.51 [M+H]+.
2.2.3. 20-Aminomethyl-60-(adenine-9-yl)-morpholine 6 (Scheme 1)
Compound 2b was obtained from 1b as described above for 2d. Rf 0.69 (CH2Cl2:EtOH
9.5:0.5); mmax/cmꢀ1 2101; dH (400 MHz, (CD3)2CO) 1.70 (1H, dd, J 10.5, 11.0, H50a), 2.21
(1H, dd, J 9.9, 11.4, H30a), 3.16 (1H, dt, J 11.0, 2.4, H50e), 3.39 (1H, dd, J 13.0, 6.0,
N3CH2–), 3.45 (1H, dd J 13.0, 4.0, N3CH2–), 3.60 (1H, dt, J 11.4, 2.4, H30e), 4.68 (1H,
m, H20), 6.55 (1H, dd, J 10.5, 2.4, H60), 7.16–7.72 (18H, m, Tr, mBz, pBz), 8.08 (2H,
bd, J 7.6, oBz), 8.25 (1H, s, H8(Ade)), 8.65 (1H, s, H2(Ade)); m/z 380.43 [M-Tr+2H]+
(The Tr protective group was removed during the sample preparation). The crude product
2b (1.6 g, 2.2 mmol) was dissolved in ethanol (25 mL), and 200 mg Pd/C (5%), was added.