Bromopinacolone → 1-[1-(3,3-Dimethyl-2-oxobutyl)-6-methoxy-1H-indazol-3-yl]-2-methylprop-1-en-1-yl dimethyl phosphate

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Reaction Steps

Dissolve 0.52 g 1-(6-methoxy-1H-indazol-3-yl)-2-methylprop-1-en-1-yl dimethyl phosphate from the Step B above in 10 mL dry DMF. Weigh in 0.626 g cesium carbonate. Add 0.315 g (0.237 mL) 1-bromo-3,3-dimethylbutan-2-one and stir the resulting mixture at room temperature for 2 hours and at 50° C. for one day. Remove half of the DMF under reduced pressure. Dilute the residue with 1:1 MeCN and water, and purify on RP-HPLC using 20-100% MeCN gradient without TFA to give the title compound as a colorless solid. The title compound recrystallizes from 1:1 EtOAc and hexanes. 1H NMR (CDCl3, 500 MHz) δ 7.70 (d, 9.0 Hz, 1H), 6.86 (dd, 2.0 & 8.7 Hz, 1H), 6.48 (d, 2.1 Hz, 1H), 5.33 (s, 2H), 3.87 (s, 3H), 3.57 (d, JP-H=11.4 Hz, 6H), 2.02 (d, JP-H=2.5 Hz, 3H), 1.83 (d, JP-H=3.4 Hz, 3H), 1.32 (s, 9H).

Provenance & Evidence