Acetyl chloride → 2-Chloro-6-(2-isopropylimidazol-1-yl)purine

Participants

Reaction Conditions

Reaction Steps

9-(2,3,5-Tri-O-acetyl-β-D-ribofuranosyl)-2-chloro-6-(2-isopropylimidazol-1-yl)purine (2.96 g, 5.7 mmol, contaminated with 2-isopropylimidazole) was dissolved in HOAc (190 mL). To the solution was added AcCl (1.9 mL, 2.10 g, 26.7 mmol), and the mixture was stirred at 65° C. for 20 h in a sealed flask (reaction was complete, TLC). Volatiles were evaporated in vacuo, and the residue was washed (CH2Cl2) and dissolved in 0.1 N NaOH/H2O (200 mL). Precipitation with CO2 gave 2-chloro-6-(2-isopropylimidazol-1-yl)purine (0.675 g, 54%). This solid was washed (boiling MeOH/iPrOH) to give the title compound (0.60 g, 48%): mp 268-268.5° C.; UV (MeOH) max 213, 254, 288 nm (∈ 26 100, 4600, 13 100), min 239, 257 nm (∈ 3700, 4600); 1H NMR (500 MHz, DMSO-d6) δ 14.06 (s, 1H), 8.71 (s, 1H), 8.36 (s, 1H), 7.07 (d, J=1.6 Hz, 1H), 3.93 (br s, 1H), 1.29 (d, J=6.8 Hz, 6H); 13C NMR (125 MHz, DMSO-d6) δ 156.4, 154.3, 151.0, 146.5, 145.8, 127.9, 122.0, 120.4, 27.7, 21.6; HRMS m/z 285.0626 (MNa+[C11H11ClN6Na]=285.0631). Anal. Calcd for C11H11ClN6: C, 50.29; H, 4.22; N, 31.99. Found: C, 50.12; H, 4.27; N, 32.16.

Provenance & Evidence