Methyl iodide → 2,6-dichloro-9-methyl-9H-purine

Participants

Reaction Steps

To a solution of 2,6-dichloropurine (1.10 g, 5.82 mmol) in anhydrous THF (5.0 mL) was added tetra-n-butylammonium fluoride (0.58 mL, 10.58 mmol, 1.8 eq; 1M in THF). Methyl iodide (0.40 mL, 6.42 mmol, 1.1 eq) was added, and the reaction mixture was stirred at RT under N2 for 30 minutes. The reaction mixture was then diluted with ethyl acetate (250 mL). The organic layer was washed with aqueous saturated sodium thiosulfate solution, water and brine, then dried (Na2SO4), filtered and evaporated in vacuo. The resultant residue was purified by column chromotagraphy (Si-PPC, gradient 5 to 100% ethyl acetate in hexane) to give 2,6-dichloro-9-methyl-9H-purine (a-2) as a white solid (780 mg, 66%) followed by gradient 0 to 30% methanol in ethyl acetate to give 2,6-dichloro-7-methyl-7H-purine (a-3) as a white solid (346 mg, 29.3%). 1H NMR of 2,6-dichloro-9-methyl-9H-purine (DMSO-d6, 400 MHz) δ ppm 8.75 (s, 1H), 3.83 (s, 3H). 1H NMR of 2,6-dichloro-7-methyl-7H-purine (DMSO-d6, 400 MHz) δ ppm 8.80 (s, 1H), 4.09 (s, 3H).

Provenance & Evidence