N,N-Dibutyl-2-[3-(2,2-dimethylpropanoyl)-6-methoxy-1H-indazol-1-yl]acetamide → 2-(tert-Butyl)-6-methoxy-1H-indole

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Reaction Steps

To a solution of 17.20 g N-(5-methoxy-2-methylphenyl)-2,2-dimethylpropanamide prepared in Step A above in 300 mL anhydrous THF under nitrogen in a −3° C. bath was added 62.2 mL 2.5 M n-BuLi in hexanes. After stirring for 1 hour, the cooling bath was removed. After four days, it was quenched by addition of saturated ammonium chloride solution and concentrated under reduced pressure to remove solvents. The residue was diluted with 1 N HCl and extracted with ether. The combine ether extract was washed with 5% NaHCO3, and saturated brine, dried over anhydrous Na2SO4 and evaporated to give a crude product. It was purified by SGC with 10-25% EtOAc in hexanes to give title compound as yellowish solid followed by recovered starting material. 1H NMR (CDCl3, 500 MHz) δ 7.85 (br s, 1NH), 7.42 (d, J=8.7 Hz, 1H), 6.87 (d, J=2.3 Hz, 1H), 6.77 (dd, J=2.3 & 8.4 Hz, 1H), 6.19 (d, J=2.2 Hz, 1H), 3.86 (s, 3H), 1.40 (s, 9H). LC-MS: 3.68 min. (m/Z=204.1).

Provenance & Evidence