2-[BIS(TERT-BUTOXYCARBONYL)AMINO]-5-BROMOPYRIMIDINE

Step A: A mixture of 2-amino-5-bromopyrimidine (2.75 g, 15.8 mmol) and di-tert- butyl dicarbonate (7.58 g, 34.8 mmol) in pyridine (30 mL) was stirred at 70 °C overnight, then the solvent was removed. The residue was partitioned between EtOAc and aqueous HC1 (1 N). The aqueous layer was extracted with EtOAc. The combined organics were dried over NaS0Step A: Part II: Synthesis of Heteroaryl Boronic Acid; Step 1N, N-di-t-Butoxycarbonyl-5-bromopyrimidin-2-amine. Di-tert-butyl dicarbonate (5.52 g, 2.2 eq) was added to a solution of 2-amino-5-bromopyrimidine (2.0 g, ) and 4- dimethylaminopyridine (140 mg, 0.1 eq) in anhydrous THF (18 mL). The reaction was stirred at room temperature under a nitrogen atmosphere overnight. A few drops of water were then added to the reaction to quench it, and the crude was then concentrated and purified by chromatography (gradient: 95:5 hexanes:EtOAc to 80:20 hexanes:EtOAc) delivering the product (3.70 g, 86percent yield). To a solution of 45 (5.0 g, 28.7 mmol) in THF (50 mL) are added di-tert-butyi dicarbonate (13.8 g, 63.2 rnrnoi), TEA (12.0 rnL, 86 mmol), and DMAP (360mg, 2.87 mmol). After stirring at 60 °C for 16 hour, the mixture is concentrated and purified by silica gel column chromatography (EA:PE = 1:5) to give 46 as a while solid (9.0 g, 84percent yield). (MS: [M+HI 374.1)Part B: