N,N,N',N'-Tetramethylethylenediamine → ethyl(RS)-2-oxo-3-phenylbutyrate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 1.6 N solution of n-butyllithium in hexane was run dropwise into a solution, cooled to the region of −70° C., of 33 g (0.220 mol) of (RS)-2-phenylpropionic acid in 220 cm3 of tetrahydrofuran and of 44 cm3 of N,N′-tetramethylethylenediamine. After having stirred the reaction mixture for three hours at −70° C., the reaction mixture was returned to a temperature in the region of 20° C. and the solution obtained was run into a solution of 75 cm3 (0.55 mol) of ethyl oxalate in 110 cm3 of tetrahydrofuran, the temperature being maintained at −75° C., for 1 hour. The reaction mixture was hydrolysed with 800 cm3 of a saturated aqueous sodium hydrogencarbonate solution, extracted with three times 100 cm3 of ethyl acetate, washed with three times 50 cm3 of a normal aqueous hydrochloric acid solution, dried over sodium sulphate and concentrated under reduced pressure. 44 g (97%) of ethyl (RS)-2-oxo-3-phenylbutyrate were then obtained in the form of an orange oil, the characteristics of which were as follows:

Herkunft & Nachweise