Triethylamine → 1-Methacryloylindoline-2-carboxylic acid ethyl ester

Participants

Reaction Steps

To a chilled and stirred mixture of 2,3-dihydroindole-2-carboxylic acid ethyl ester (4.78 g., 25.0 mmole), triethylamine (2.7 g., 26.7 mmole), and anhydrous ether (500 ml) was added dropwise methacryloyl chloride (2.9 g., 27.7 mmole) dissolved in a small amount of ether. After the completion of the addition, the ice bath was removed, and the reaction mixture was stirred for 4 hours. The precipitate which separated was removed by filtration, and the filter residue was washed with ether. The combined filtrate and washing were washed with water (two 700ml portions), then with saline, and dried over anhydrous magnesium sulfate. Evaporation of the solvent under reduced pressure on a rotary evaporator gave the product as an oil. The product was purified by preparative HPLC (Prep LC/System 500, Waters Associates), using a micro porasil column eluted with a mixture of hexane (95%) and ethyl acetate (5%). The crude oil may be used directly in the following reaction (Example 2).

Provenance & Evidence