Determination of Tritium Distribution in Uracil and Uridine. I

Abstract

1. Tritiated uridine was degraded by the periodate and phenyl-hydrazine method to uracil without release of ³H from pyrimidine ring at the C5 position but, by treatment with 12 N perchloric acid, the C5-³H was completely eliminated.
2. The release of C5-³H from uracil and uridine by boiling with 1 N acid was first order and the velocity constants were calculated. The C6-³H was very stable to this acid treatment.
3. The distribution of ³H in commercial 5, 6-³H uracil and 5, 6-³H uridine, which were tritiated by catalytic exchange in ³H₂O, was measured by bromination and by acid treatment. The percentage of III at C6 was 0.7-0.8% and 2-4 % of the total ³H bound in the pyrimidine ring of uracil and uridine, respectively.