Pyrazole → tert-butyl 2-[4-[2-[[(3R,3aR,6R,6aR)-3-hydroxy-2,3,3a,5,6,6a-hexahydrofuro[3,2-b]furan-6-yl]oxy]-6-chloro-1-(2-trimethylsilylethoxymethyl)-imidazo[4,5-b]pyridin-5-yl]phenyl]-4,6-dihydropyrrolo[3,4-c]pyrazole-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

A vial was charged with (3R,3aR,6R,6aR)-6-[5-(4-bromophenyl)-6-chloro-1-(2-trimethylsilylethoxymethyl)imidazo[4,5-b]pyridin-2-yl]oxy-2,3,3a,5,6,6a-hexahydrofuro[3,2-b]furan-3-ol (501.8 mg, 0.861 mmol), tert-butyl 4,6-dihydro-2H-pyrrolo[3,4-c]pyrazole-5-carboxylate (240.3 mg, 1.148 mmol), tripotassium phosphate (581.6 mg, 2.74 mmol), and copper (I) iodide (37.2 mg, 0.195 mmol). The vial was evacuated (3×) and backfilled with nitrogen. Trans-N,N′-dimethylcyclohexane-1,2-diamine (55 μl, 0.348 mmol) and dioxane (1.7 ml) were added to the vial to give a hazy suspension that was heated to 100° C. for 24 h. The reaction mixture was cooled to room temperature and partitioned between EtOAc (100 ml) and water (100 ml). The aqueous layer was extracted with EtOAc (2×50 ml). The organic layers were combined, washed with brine (1×30 ml), dried over MgSO4, filtered, and evaporated under reduced pressure to give a pale green residue. Flash chromatography of the residue utilizing a 40 g silica RediSep Rf® column and employing a 0-100% EtOAc/hexane gradient afforded a mixture of the two pyrazole linked regioisomers as a pale amber foam. LC-MS: calculated for C34H43ClN6O7Si 710.27 observed m/e: 711.29 (M+H)+ (Rt 1.30/2 min)

Provenance & Evidence