[en] Labelled 11-methyl prostaglandins have been prepared via the catalytic tritium reduction of 11-iodomethyl intermediates. Two examples are reported for the preparation of such 11-iodomethyl precursors in which the desired lower side chain is attached in non-radioactive steps. Subsequent tritium hydrogenolysis of the 11-iodomethyl lactones followed by addition of the delta 5 cis-double bond yielded prostaglandins having specific activities of 10-15 Ci/mmol

[en] The main emphasis of this symposium, is on the new applications of labeled compounds. Sessions have been organized in the following areas: The Preparation and Use of Labeled Peptides; The Application of Radioligands in Binding Studies; The Utility of Labeled Monoclonal Antibodies; The Application of Labeled Compounds in Recombinant DNA Research; and The Use of Deuterated Analogs of Drugs as Medicinal Agents. In addition, sessions have been organized in: The Use of Labeled Compounds in NMR Imaging; The Applications of Deuterium and Nitrogen-15 NMR Spectroscopy; and The State of the Art in the Instrumentation for the Analysis of Isotopically Labeled Compounds. refs.; figs.; tabs

[en] In this paper experimenters prepared important biologically active substances with high specific activity tritium labels by multistep synthesis using labeled intermediates. Retrosynthetic analysis of the substance leads to an aromatic intermediate which can be iodinated. Catalytic hydrodehalogenation with tritium gas provides the labeled intermediate which is used without dilution in the forward synthesis of the desired substance. Compounds that cannot be tritium labeled by more conventional means have thus been prepared at specific activities of 40 to 50 Ci/mole

[en] Retinyl acetate (4a) has been prepared with a tritium label at the C-11 and C-12 positions by partial reduction of oxenin (1) with tritium gas followed by acetylation and rearrangement. Specific activities of up to 40 curies/mmole have been attained. By alkaline hydrolysis, retinol (5) has been obtained and derivatized as one of several retinyl esters or has been oxidized to all-trans retinoic acid (6) having equally high specific tritium activities. From beta ionone (12), 13-cis retinoic acid (10) has been elaborated in a variety of isotopically labeled forms. A key reaction in the sequence, the Wittig coupling of the triphenylphosphonium derivative of vinyl beta ionol (15a-c) and the butenolide, 5-hydroxy-4-methyl-2(5H)-furanone (8), provides access to 13-cis retinoic acid and its 4-oxo metabolite labeled with either isotopic hydrogen or carbon. (author)