Sodium Carbonate → 3-[6-Chloro-2-(4-nitro-phenyl)-pyrimidin-4-yl]-8-oxa-3-aza-bicyclo[3.2.1]octane

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Reaction Steps

3-(2,6-Dichloropyrimidin-4-yl)-8-oxa-3-aza-bicyclo[3.2.1]octane (9) was dissolved in toluene (24 mL) and EtOH (16 mL). To this solution was added 4-nitrophenylboronic acid pinacol ester (1.25 g, 5 mmol) and 8 mL of a 2M solution of Na2CO3. The mixture was degassed by bubbling nitrogen through the solution. Pd(PPh3)4 (231 mg, 0.2 mmol) was added and the mixture was heated under reflux overnight. The mixture was filtered. The solids, consisting of 3-[2,6-bis-(4-nitro-phenyl)-pyrimidin-4-yl]-8-oxa-3-aza-bicyclo[3.2.1]octane (15), were collected and washed with water and dichloromethane. The combined filtrates were concentrated, dissolved in dichloromethane and washed with saturated NaHCO3. The organic phase was dried (MgSO4), filtered and concentrated. The crude product was added to a silica gel column and was eluted with 10-50% ethyl acetate in hexanes. Collected fractions were concentrated to give 3-[6-chloro-2-(4-nitro-phenyl)-pyrimidin-4-yl]-8-oxa-3-aza-bicyclo[3.2.1]octane (13, 135 mg, 10%) along with 3-[2-chloro-6-(4-nitro-phenyl)-pyrimidin-4-yl]-8-oxa-3-aza-bicyclo[3.2.1]octane (14, 110 mg, 8%).

Provenance & Evidence