tert-Butyl piperazine-1-carboxylate → Tert-butyl 4-[2-[(4-methylsulfonylphenyl)methoxy]pyrimidin-5-yl]piperazine-1-carboxylate

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5-bromo-2-(4-(methylsulfonyl)benzyloxy)pyrimidine (1.03 g, 3.00 mmol), tert- butyl piperazine-1-carboxylate (624.6 mg, 3.35 mmol), TRIS(DIBENZYLIDENEACETONE)DIPALLADIUM(0) (154.3 mg, 0.17 mmol),2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (100.0 mg, 0.16 mmol) and sodium 2-methylpropan-2-olate (454.4 mg, 4.73 mmol) were mixed with toluene (20 mL). N2 was bubbled through the solvent for 15 minutes.The resulting mixture was stirred at 80 °C for over night under N2.The reaction mixture was filtered through celite. The reaction mixture was evaporated to dryness and redissolved in EtOAc (75 mL), and washed sequentially with water (2x75 mL) and saturated brine (100 mL). The organic layer was dried over MgSO4, filtered and evaporated to afford crude product. The crude product was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in isohexane. Pure fractions were evaporated to dryness to afford tert-butyl 4-(2-(4-(methylsulfonyl)benzyloxy)pyrimidin-5-yl)piperazine-1-carboxylate (1.664 %) as a white solid. The product was not pure! The crude product was purified by flash alumina chromatography, elution gradient 0 to 70% EtOAc in isohexane. Pure fractions were evaporated to dryness to afford tert-butyl 4-(2-(4-(methylsulfonyl)benzyloxy)pyrimidin-5-yl)piperazine-1-carboxylate (1.664 %) as a white solid. The product was still not pure but was handed in for testing anyway, as 92% pure by NMR.

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