N-bromobutanimide → 7-Bromo-1-[(S)-2-(tert-butyldimethyl-silanyloxy)-propyl]-1H-indazol-6-ol

関与物質

反応手順

To a solution of the product from Step B (3.79 g, 12.4 mmol) in anhydrous THF (100 mL) at 0° C. was added N-bromosuccinimide (2.20 g, 12.4 mmol) in 3 portions over 10 min. After 20 min the mixture was poured into a saturated aqueous solution of sodium bisulfite (100 mL) and extracted with EtOAc (3×200 mL). The combined extracts were dried (MgSO4) and evaporated to a residue (4.79 g). Chromatography (silica, 10% EtOAc/hexane) gave a solid (3.66 g, 77%): mp 103-105° C.

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