Sodium Iodide → Phosphoric acid di-tert-butyl ester 2-cyano-6-oxo-1-propyl-8-[1-(3-trifluoromethyl-benzyl)-1H-pyrazol-4-yl]-1,6-dihydro-purin-7-ylmethyl ester

Participants

Reaction Steps

A mixture of 6-Oxo-1-propyl-8-[1-(3-trifluoromethyl-benzyl)-1H-pyrazol-4-yl]-6,7-dihydro-1H-purine-2-carbonitrile (0.5 g, 0.0012 mol), K2CO3 (0.485 g, 0.0036 mol) and acetone (10 ml) were taken and stirred for 20 minutes at room temperature. NaI (0.702 g, 0.0047 mol) was added and then Phosphoric acid di-tert-butyl ester chloromethyl ester (0.619 g, 0.0024 mol in 2 ml acetone) was added to the reaction mixture drop wise. The reaction mixture was heated at 45° C. for 16 h. The reaction mixture was filtered through celite and washed with acetone. The organic layer was concentrated and the residue was taken in ethyl acetate (30 ml) and saturated NaHCO3 solution (20 ml). The organic layer was separated and washed with saturated sodium thiosulphate solution (20 ml). The organic layer was washed with 0.5 N HCl solution (20 ml) and brine solution (20 ml). The organic layer was dried over sodium sulphate and evaporated to obtain brown colored mass. The crude product, which is a mixture of N7 and N9 isomers was purified by column chromatography (230-400 mesh silica gel and it was first treated with 5% triethyl amine in hexane) using 5-20% acetone in hexane (with 0.5 to 1% triethyl amine) as an eluent to obtain N7 isomer (0.34 g, 45%) and N9 isomer (0.11 g, 14%)

Provenance & Evidence