Dimethyl Sulfoxide → Aminoisobutyric acid

Participants

Reaction Steps

A mixture of 500 mg. (5.0 mmole) of 2-methylalanine and 800 mg. (5.0 mmole) of m-chlorobenzyl chloride in 10 ml. of dimethylsulfoxide is stirred at 60° C. for 6 hours and then allowed to cool to 20°-25° C. over 12 hours. Water, 150 ml., is added followed by a saturated sodium carbonate solution until a basic pH of 8 is obtained. The product is extracted into 50 ml. of ethyl ether which is then washed with four 25 ml. portions of water, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure (15-20 mm.) at 35°-40° C. The residue is converted into the hydrogen fumarate salt with 0.40 g. fumaric acid in 25 ml. 80% ethanol-20% ethyl acetate solution followed by precipitation with hexane. After filtering and drying, the m-chlorobenzyl ester of 2-methylalanine as the hydrogen fumarate salt containing one equivalent of fumaric acid as a co-precipitant, m.p. 144.0°-149.0° C., is obtained. Further recrystallization from the aforementioned ethanol-ethyl acetate-hexane system gives an analytical sample.

Provenance & Evidence