1-acetyl-5-fluoro-2,3-dihydro-3,3-dimethyl-1H-Indole → 5-Fluoro-3,3-dimethylindoline

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Reaction Conditions

Reaction Steps

According to the procedure described in S. Coulton et al. WO9925709 with the following modifications. N-(4-Fluoro-phenyl)-N-(2-methyl-allyl)-acetamide (5 grams, 24.12 mmol) was added to a microwave tube with aluminum trichloride (7 grams, 52.4 mmol). The tube was capped and heated to 150° C. for 20 minutes under microwave. The slurry was worked up with water and ethyl acetate, the organic layer was extracted with 3 washes of saturated sodium bicarbonate solution and the organic layer was dried over magnesium sulfate. The solution was then filtered and rotary evaporated to yield pure 1-(5-Fluoro-3,3-dimethyl-2,3-dihydro-indol-1-yl)-ethanone in quantitative yield. This was converted to the free indoline by suspending the entire 5 grams of product in 20 mL of 6 M HCl and heating in a microwave to 200° C. for 10 minutes. The resulting 5-Fluoro-3,3-dimethyl-2,3-dihydro-1H-indole crystallized on cooling as the hydrochloride salt in quantitative yield. This material was identical to the previously reported compound.

Provenance & Evidence