18-Crown-6 → N-cyclohexyl-4-[(2,6-dichloro-9H-purin-9-yl)methyl]-N-methylbenzamide

Participants

Reaction Steps

To a stirred solution of 2,6-dichloropurine (500 mg, 2.64 minol) in acetonitrile (40 mL)at -10° C. was added 18-crown-6 (48 mg, 0.18 mmol) and potassium hydride (106 mg after ether wash of 35% dispersion in mineral oil, 2.64 mmol). The reaction was allowed to warm to room temperature and stirred for an additional 30 min. 4-Bromomethyl-N-methyl-N-cyclohexyl benzamide (900 mg, 2.90 mmol) was added in small amounts over 10 min and the mixture stirred under argon at 25° C. After 18 hr, the reaction was quenched by adding drops of acetic acid and the solvent removed under reduced pressure at <45° C. The residue was dissolved in ethyl acetate and washed with aqueous potassium carbonate, water and brine. The solvent was removed and the crude mixture (1.28 g) chromatographed (silica gel, CH2Cl2 /MeOH 100/7) to give pure 6A (278 mg, 25%). m.p. 134°-136° C. Anal calcd. for C20H21N5OCl2.0.25 H2O:C, 56.80; H, 5.08; N, 16.56; Cl, 16.80. Found: C, 57.00; H, 5.09; N, 16.20; Cl, 16.59.

Provenance & Evidence