Trimethylpyruvic acid → (S)-3,3-dimethyl-2-(1-phenylethylimino)-butyric acid

関与物質

反応条件

反応手順

8.9 g (47 mmol) of (S)-(2,2-dimethylpropylidene)-(1-phenylethyl)-amine (J. L. Fauchure, C. Petermann, Helv. Chim. Acta 1980, 63, 824) were dissolved in 10 ml of diethyl ether with the exclusion of moisture. 8.1 g (50 mmol) of trimethylpyruvic acid in 10 ml of diethyl ether were added dropwise to this solution while cooling with ice. Subsequently, the mixture was stirred at 0° C. for a further 2 hours and at room temperature for 6 hours. Colorless crystals form over 2 days and these were suspended in 50 ml of diethyl ether, filtered off and washed twice with 5 ml of diethyl ether each time. After drying in a vacuum there were obtained 8.9 g (81%) of (S)-3,3-dimethyl-2-(1-phenylethylimino)-butyric acid (internal salt) of melting point 135°-136° C. [α]=-14.4 (c=0.16, CH2Cl2).

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