Reaction Steps
Compound 35 was prepared by the same procedure as described for the preparation of 6a using 4a (415 mg, 1.41 mm), ethyl chloroacetate (207 mg, 0.18 ml, 1.68 mm), DIEA (91 mg, 0.12 ml, 0.70 mm), and DMF (5 ml): yield 204 mg (38%), MS: m/z 381 (M+H)+; 1HNMR (DMSO-d6) δ 8.06 (s, 1H, H-2), 7.11 (bs, 2H, 6-NH2), 5.73 (d, 1H, H-1′, J1′,2′=5.4 Hz), 5.33 (bd, 1H, OH-2′, J2′-2′OH=4.7 Hz), 5.19 (bd, 1H, OH-3′, J3′-3′OH=4.9 Hz), 5.03 (ddd, 1H, H-2′, J1′,2′=5.4 Hz, J2′,3′=5.7 Hz, J2′-2′OH=4.7 Hz), 4.17 (ddd, 1H, H-3′, J2′,3′=5.7 Hz, J3′,4′=4.4 Hz, J3′-3′OH=4.9 Hz), 4.02 (q, 2H, CH3—CH2), 3.92-3.99 (m, 1H, H-4′), 3.27 (bs, 2H, NCH3—CH2), 2.83-2.90 (m, 1H, 5′-CH2), 2.70-2.79 (m, 1H, 5′-CH2), 2.53 (s, 3H, 8-CH3), 2.31 (s, 3H, N—CH3), 1.13 (t, 3H, OCH2—CH3); UV λmax, nm, pH 1, 258.9 (∈ 16,100), pH 7, 260 (∈ 15,900), pH 13, 260.1 (∈ 16,200).
