Reaction Steps
A mixture of 3a (150 mg, 0.50 mmol) and a 2M solution of dimethylamine in methanol (10 mL) in a steel bomb was heated for 2 days at 90° C. The reaction mixture was concentrated to dryness and purified by column chromatography (elution with 4:1:0.15 chloroform:methanol:NH4OH). The desired fractions were combined, concentrated and dried in vacuo: yield 38 mg (25%); MS m/z 309 (M+H)+; 1HNMR (DMSO-d6) δ 8.08 (s, 1H, H-2), 7.11 (bs, 2H, 6-NH2), 5.74 (d, 1H, H-1′, J1′,2′=5.5 Hz), 5.31 (d, 1H, OH-2′, J2′-2′OH=5.9 Hz), 5.18 (d, 1H, OH-3′, J3′-3′OH=5.4 Hz), 5.03 (ddd, 1H, H-2′, J1′,2′=5.5 Hz, J2′,3′=4.6 Hz, J2′-2′OH=5.9 Hz), 4.15 (ddd, 1H, H-3′, J2′,3′=4.6 Hz, J3′,4′=5.5 Hz, J3′-3′OH=5.4 Hz), 3.91-3.96 (m, 1H, H-4′), 2.55-2.61 (m, 1H, 5′-CH2), 2.53 (s, 3H, 8-CH3), 2.42-2.48 (m, 1H, 5′-CH2), 2.14 (bs, 6H, N—(CH3)2); UV λmax, nm, pH 1, 258.5 (∈ 15,300), pH 7, 259.3 (∈ 15,300), pH 13, 260.1 (∈ 15,500). Anal. (C13H20N6O3.0.35CHCl3.0.5C2H5OH) C, H, N.
