Tritium Labeling of Androst-4-ene-3,17-dione by Liquid-Phase Selective Hydrogenation and Factors Affecting the Process

Androstenedione labeled with tritium at positions 1 and 2 was prepared. The molar radioactivity of the sample prepared using homogeneous catalysts was as high as 1.4-1.5 PBq mol^{- 1}. [1,2-³H]Androst-4-ene-3,17-dione can be converted into the [1-³H]steroid with the molar radioactivity of 0.9 PBq mol^{- 1}.     

Specific features of deuterium and tritium labeling of Pro-Gly-Pro-Leu and of physiologically active amino acids

γ-Aminobutyric acid (GABA), 3-hydroxy-L-tyrosine (D0PA), and Pro-Gly-Pro-Leu were labeled with hydrogen isotopes. The mean deuterium content per molecule was 7.5 atoms in Pro-Gly-Pro-Leu and up to 4 atoms in GABA and DOPA. The incorporation of isotopes depending on the reaction conditions was monitored by mass spectrometry. The isotope exchange efficiency was found to strongly depend not only on the reaction temperature and catalyst: substrate ratio, but also on processes occurring on the support surface.     

Specific features of deuterium and tritium labeling of SB258585

Samples of SB258 585 labeled with hydrogen isotopes were synthesized. [²H]SB258 585 containing one ²H atom per molecule and [³H]SB258585 with the molar radioactivity of 15 Ci mmol^?1 were obtained in preparative amounts. From 0.18 to 1.5 ²H atoms were incorporated, on the average, into an SB 258 585 molecule depending on the reaction conditions. The isotope exchange efficiency strongly depends not only on the catalyst-substrate ratio and on the reaction temperature, but also on processes occurring on the support surface. The isotope effects strongly influence the degree of deuterium or tritium incorporation into the samples in cases when the organic compound largely decomposes in the course of the reaction.     

Effect of Technetium on the Efficiency of Solid-Phase Isotope Exchange

Tritium-labeled hexadecane, glycine, and -aminocaproic acid were prepared in the presence of supported palladium catalysts (straight and impregnated with technetium). The degree of isotope exchange is strongly affected by the reaction conditions. In isotope exchange of gaseous tritium with hexadecane, the degree of exchange obtained with the technetium-impregnated catalysts exceeds that obtained with the monometallic catalysts. The nature of the synergism is discussed.     

Synthesis of Pro-Pro-Ile,a corticoliberin fragment,labeled with tritium in proline unit

Boc-Δ³Pro-Pro-Ile-OBzl and Boc-Pro-Δ³Pro-Ile-OBzl were synthesized. Tritium-labeled Pro-Pro-Ile was prepared by their hydrogenation in a tritium atmosphere in the presence of a catalyst. In the reduction of Boc-Δ³Pro-Pro-Ile-OBzl and Boc-Pro-Δ³Pro-Ile-OBzl, elimination of the Bzl protective group occurs faster than hydrogenation of the 3,4-dehydroproline residue (benzene and dioxane were used as solvents). The resulting Boc-Δ³Pro-Pro-Ile-OH and Boc-Pro-Δ³Pro-Ile-OH are poorly soluble in aprotic solvents, which accounts for the low yield of the desired tritium-labeled peptides.     

Influence of the Catalyst and Support on the Efficiency of Solid-Phase Isotope Exchange between Gaseous Tritium and Phenylalanine

Tritium-labeled phenylalanine was prepared by solid-phase catalytic isotope exchange. Palladium, rhodium, and platinum supported on carbon, alumina, barium sulfate, and calcium carbonate were tested as catalysts. The molar radioactivities of amino acids labeled under different conditions differ by a factor of several tens. The degree of isotope exchange strongly depends not only on the support, but also on the substrate application procedure.     

Effectiveness of using natural products in diet of patients with hypertension

Having included in nutrition ration of patients with hypertension of natural vegetation product the authors revealed its influence on metabolic processes in human organism. It was found normalization of tone of brain and conjunctiva vessels, arterial pressure, rhythm and rate of pulse; the decrease of intensity of heart repolarization disorders and signs of vitamin-mineral insufficiency. It was observed head and heart pain relief. There were no significant differences in the dynamics in control group.