3,4-dihydro-2H-pyran → 6-chloro-9-(tetrahydro-2H-pyran-2-yl)-9H-purine

Participants

Reaction Steps

To a warmed (60° C.) slurry of 6-chloropurine (20 g, 0.1294 mol) and p-toluenesulfonic acid monohydrate (0.35 g), dihydropyran (13.4 mL, 0.172 mol) was added with stirring over a period of 30 min. After an additional 30 min of heating, the mixture was allowed to cool to room temperature for 1 h. Concentrated ammonium hydroxide (12 mL) was added and stirring was continued for 5 min. The solution was washed with water (4×70 mL) and the organic layer was dried (Na2SO4), filtered and concentrated in vacuo to give a syrup (about 29 g) which slowly crystallized upon standing. Extraction with boiling hexane gave the product as a solid, 24.36 g in two crops (78%), mp 70°-71° C.

Provenance & Evidence