Reaction Steps
To a stirred solution of 14e (218 mg, 0.67 mmol) and 1H-pyrazole-1-carboxamidine hydrochloride50 (196 mg, 1.34 mmol) in anhydrous DMF (5 mL) was added DIEA (479 mg, 0.65 mL, 3.7 mmol) under nitrogen at 5° C. Stirring was continued at room temperature overnight. The reaction mixture was concentrated to dryness and the product was purified by column chromatography (silica gel 230-400 mesh, elution with 4:1:0.3 chloroform:methanol:NH4OH). The desired fractions were combined, concentrated, and dried in vacuo to give a white solid: yield 219 mg (89%), MS: m/z 366 (M+H)+; 1HNMR (DMSO-d6) δ 8.34 (s, 1H, H-8), 8.15 (s, 1H, H-2), 7.48, 7.37, 7.28 (bs, NHs), 5.87 (d, 1H, H-1′, J1′,2′=5.2 Hz), 5.50 (d, 1H, 2′-OH, J2′-2′OH=5.7 Hz), 5.28 (d, 1H, 3′-OH, J3′-3′OH=4.5 Hz), 4.65 (ddd, 1H, H-2′, J1′,2′=5.2 Hz, J2′,3′=5.1 Hz, J2′-2′OH=5.7 Hz), 4.12 (ddd, 1H, H-3′, J2′,3′=5.1 Hz, J3′,4′=4.6 Hz, J3′-3′OH=4.5 Hz), 4.0-4.10 (bm, 1H, H-4′), 3.30-3.50 (bm, 2H, 5′-CH2), 3.12-3.28 (bm, 2H, NH—CH2), 2.55-2.65 (bm, 2H, N(CH3)—CH2), 2.25 (bs, 3H, N—CH3); UV λmax, nm, pH 1, 256.3 (∈ 10,900), pH 7, 259 (∈ 11,300), pH 13, 259 (∈ 11,000). Anal. (C14H23N9O3.0.05CHCl3.3.5H2O) C, H, N.
