METHOD OF PREPARING TRITIUM LABELLED ALIPHATIC α- HALOGEN ACIDS Russian patent published in 1997 - IPC

FIELD: organic chemistry, biology, and medicine. SUBSTANCE: to produce tritium labelled aliphatic α-halogen acids, isotope exchange reaction is carried between hydrogen of organic compound and tritium. The organic compound includes respective α-amino acids. Amino group is substituted for chlorine in the resulting tritium labelled α-chloro acids, chlorine or other halogens are optionally substituted in the resulting tritium labelled α-chloro acids to produce respective tritium labelled α-bromo or iodo acids. Tritium labelled amino acids are produced by carrying out solid phase isotope exchange reaction of hydrogens of respective α-amino acids with gaseous tritium in the presence of 10 % Pd/C or 5 % Pd α catalyst at 140-160 C or 160-180 C, respectively for 15-25 minutes, catalyst to compound ratio being (4.5-5.5):1 ng/mg. Substitution of amino group for chlorine is carried out by reaction of diazotization of nitro group of the respective tritium labelled BaSO₄-amino acid in the presence of hydrochloric acid at α-amino acid to sodium nitrite to hydrochloric acid ratio of (2.3-2.6): 320:(1750-1850) mcmole/mcmole/mcl. Substitution of chlorine for other halogens in tritium labelled α-chloro acid is accomplished by testing the respective tritium labelled α-chloro acid with the respective sodium halide at 70- 80 C for 25-35 min in acetone at α-chloro acid to sodium halide to acetone ratio of (2.0-2.5):(30-35): 500 mcmole/mcmole/mcl. EFFECT: more efficient preparation method. 4 cl