Synthese tritium‐markierter Aminosäuren hoher Spezifischer Aktivität

Methods for amino acid synthesis are described that involve the catalytic reduction of precursor aliphatic acids and aromatic amino acids, and the catalytic dehalogenation with tritium of brominated and iodinated precursors. The following amino acids were synthesized: /sub DL/-alanine- alpha , BETA T/sub 2/ (from alpha -acetaminoacrylic acid ethyl ester) with a specific activity of 4500 mc/mmole; /sub DL/-glutamic acid- BETA , gamma T/sub 2/ (from acetamino-(2- carbethoxyvinyl)malonic acid diethyl ester), 3000; gamma -aminobutyric acid- alpha , BETA T/sub 2/ ( gamma -phthalimidocrotonic acid methyl ester), ---; /sub DL/- alpha -aminoadipic acid-4,5T/sub 2/ (acetamino-(3-carbethoxy- DELTA /sup 1/- propenyl)malonic acid diethyl ester), 55000; /sub DL/- BETA -(3,4- dihydroxyphenyl)-alanine- alpha , BETA T/sub 2/ ( alpha -acetamino- BETA -(3,4- diacetoxyphenyl)acrylic acid, 9000; and /sub DL/-proline-2T ( DELTA 1- pyrrolinecarboxylic acid hydrochloride), 1500. Reduction was carried out with a palladiumactivated charcoal catalyst for periods of 3 min, 1 hr, 1.05 hr, 1.5 hr, and 2.5 hr for these respective compounds. For the compounds with the lower activities, a mixture of H/sub 2/ and T/sub 2/ was used. Methods for synthesizing the following are also described: /sub L/ tyrosine-3T, /sub L/- histidine-2,4T, and /sub D-/ and /sub L-/phenylalanine-2,4T. Paper chromatography showed that the puritymore » of the products, with few exceptions exceeded 98%. (BBB)« less