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step 3—A solution 142 (1 g, 4.29 mmol) in DMF (10 mL) was cooled in ice-bath and NBS (0.763 g, 4.29 mmol) was added. The colorless mixture was stirred for 2 h and then quenched with H2O. The mixture was extracted with EtOAc (2×50 mL). The combined extracts were washed sequentially with H2O and brine, dried (Na2SO4), filtered and concentrated in vacuo. The crude product was purified by SiO2 chromatography to afford 0.5 g of 6-benzyloxy-5-bromo-3-fluoro-2-methoxy-pyridine (144).

1. customquenched with H2O
2. extractionThe mixture was extracted with EtOAc (2×50 mL)
3. washThe combined extracts were washed sequentially with H2O and brine
4. dry with materialdried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe crude product was purified by SiO2 chromatography