Carbon tetrabromide → 5-Bromo-4-(bromomethyl)-2-(methylthio)pyrimidine

Beteiligte Stoffe

Reaktionsschritte

To a cold (0° C.) solution of [5-bromo-2-(methylthio)pyrimidin-4-yl]methanol (Step 13, 2.20 g, 9.34 mmol) in CH2Cl2 (46.7 mL) was added triphenylphosphine (3.19 g, 12.14 mmol) followed by carbon tetrabromide (4.03 g, 12.14 mmol). The resulting mixture was stirred cold for 1 h. LCMS trace of the aliquot indicated completion of reaction. Volatiles were removed under reduced pressure. Half of the crude material was purified by flash chromatography (SiO2, Biotage 40M cartridge). The column was eluted with an isocratic acetone/hexanes mixture (2.5%, v/v). No purification was obtained. All fractions and reaction crude were combined and purified by preparative HPLC (Kromasil 100-5C18, 100×21.1 mm) eluting with MeCN/water+0.1% TFA (51% to 62% organic in 10 min, hold 62% for 2 min, 20 mL/min). Related fractions were combined and evaporated under reduced pressure. The desired compound azeotroped with the water and was extracted with EtOAc, washed with brine, dried (Na2SO4), filtered and concentrated to afford a light brown oil as the titled compound. LCMS calc.=297.86; found=298.87.

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