Pentane → 6-Tert-butyl-4-methyl-beta-carboline-3-carboxylic acid ethyl ester

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Reaction Steps

1.2 g of aluminum trichloride is added to a suspension of 500 mg of 4-methyl-β-carboline-3-carboxylic acid ethyl ester in 15 ml of tert-butyl chloride. The mixture is stirred for 2 hours at room temperature and thereafter combined with 50 ml of pentane. The supernatant solution is removed by decanting, and the precipitate is combined with 10 ml of ethanol and 30 ml of water. After setting the pH at 3, the mixture is extracted repeatedly with ether. The collected organic phases are dried, filtered, and concentrated. Recrystallization from ether yields 250 mg of 6-tert-butyl-4-methyl-β-carboline-3-carboxylic acid ethyl ester, mp 201°-203° C. From the mother liquor, 100 mg of 6,8-di-tert-butyl-4-methyl-β-carboline-3-carboxylic acid ethyl ester can be isolated, mp 260°-263° C.

Provenance & Evidence