Triphenylphosphine → 3-bromo-4-chloro-1-(1,4-dioxaspiro[4.5]dec-8-yl)-1H-pyrazolo[3,4-d]pyrimidine

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-bromo-4-chloropyrazolo[3,4-d]pyrimidine (Intermediate B) (7.5 g, 32 mmol), 1,4-dioxaspiro[4.5]decan-8-ol (Intermediate M) (15.17 g, 96 mmol), triphenylphosphine (16.86 g, 64 mmol) in THF (275 mL) was added diethylazodicarboxylate (11.14 g, 64 mmol) in THF (50 mL) at 0° C. under nitrogen. The reaction mixture was stirred at 0° C. for 1 hour, warmed to room temperature and then stirred at room temperature for 3 hrs. The reaction mixtures was concentrated in vacuo and dissolved in hot heptane/EtOAc/DCM (5:1:5). Flash silica gel column chromatography using heptane, heptane/EtOAc (5/1) then heptane/EtOAc (4/1) gave a solid which was triturated with heptane and the solids removed by filtration to furnish 8.2 g of 3-bromo-4-chloro-1-(1,4-dioxaspiro[4.5]dec-8-yl)-1H-pyrazolo[3,4-d]pyrimidine as a white solid (69%) [Rf in 1:1 heptane:EtOAc=0.5]1H NMR (400 MHz, d6-DMSO): 8.89 (1H, s), 4.92 (1H, m), 3.90 (4H, m), 2.16 (2H, m), 1.96 (2H, m), 1.81 (6H, m) HPLC: Tr=17.11 mins, 96.6%

Provenance & Evidence