Trimethylsilylacetylene → 2-Chloro-6-(hydroxymethyl)-4-[2-(trimethylsilyl)ethynyl]pyridin-3-ol

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Reaction Steps

C2 (13.9 g, 48.6 mmol) is combined with trimethylsilylacetylene (9.6 mL, 68 mmol), bis(triphenylphosphine)palladium dichloride (1.02 g, 1.46 mmol) and cuprous iodide (139 mg, 0.73 mmol) in 80 mL CHCl3/40 mL THF under N2. TEA (21 mL, 151 mmol) is added, and the reaction is stirred 3 h at rt and is diluted with 200 mL CHCl3. The mixture is washed with 2×150 mL 5% HCl and the combined aqueous layers are extracted with 2×50 mL CHCl3. The combined organic layer is washed with 100 mL 50% saturated NaCl, is dried over MgSO4, and concentrated in vacuo to an amber oil. The crude material is chromatographed over 350 g silica gel (230-400 mesh), eluting with 35% EtOAc/hexane to afford 2-chloro-6-(hydroxymethyl)-4-[(trimethylsilyl)ethynyl]-3-pyridinol (C3) as a golden solid (92% yield). MS (EI) for C11H14ClNO2Si, m/z: 255(M)+.

Provenance & Evidence