0 1 mole of n 3 cyanopropanoyl l phenylalanine methyl ester were dissolved in 150 ml of ethanol which contained 0 1 mole of hydrogen chloride and hydrogenated with hydrogen in the presence of 0 8 gram of platinum iv oxide at normal pressure and 30 u00b0 to 35 u00b0 c after 11 2 hours the theoretically calculated amount of hydrogen was taken up the catalyst was filtered off and the filtrate evaporated to dryness the residue remaining was stirred for 2 hours with 0 2 mole of naoh in ethanol water to split off the ester group in the neutralization to ph 6 a colorless precipitate of n 4 aminobutyryl l phenylalanine crystallized out example 1 was repeated with the single difference that in place of l phenylalanine methyl ester there was treated the d phenylalanine methyl ester example 2 was repeated with the single difference that in place of n 3 cyanopropanoyl l phenylalanine methyl ester there was employed the d isomer there were obtained 20 1 grams 80 4 of theory n 4 amino butyryl d phenylalanine example 1 was repeated with the single difference that in place of the l phenylalanine methyl ester there was employed the d l phenylalanine methyl ester ______________________________________elemental analysis c sub 14 h sub 16 n sub 2 o sub 3 260 29 calculated found ______________________________________c 64 60 64 29h 6 20 5 99n 10 76 10 81______________________________________ the procedure was as in example 1 in place of the l phenylalanine methyl ester there were employed 24 8 grams 0 15 mole of l histidine methyl ester the n u03b1 3 cyanopropanoyl l histidine methyl ester crystallized out together with the n.