Synthesis and preliminary evaluation of (S)-(2-[18F]fluoro-4,5-dihydroxyphenyl)-2-methyl L-alanine, (S)-[18F]-FMEDOPA, a potentially improved imaging agent for the presynaptic dopaminergic nervous system.

The synthesis and preliminary rat biodistribution studies of (S)-(2-[18F]fluoro-4,5-dihydroxyphenyl)-2-methyl L-alanine, (S)-[18F]-FMEDOPA, a potentially improved imaging agent for the presynaptic dopaminergic nervous system, are reported. (S)-[18F]-FMEDOPA produces a higher striatum-to-cerebellum (S/C) radioactivity ratio than the currently used PET imaging agent, (S)-[18F]-FDOPA, does at 180 min after administration.

Nitroxyl analogs as inhibitors of aldehyde dehydrogenase. C-nitroso compounds.

We previously postulated that the catalase-mediated oxidation of cyanamide leads to the formation of the unstable intermediate, N-hydroxycyanamide, which spontaneously decomposes to nitroxyl, the putative inhibitor of aldehyde dehydrogenase (EC 1.2.1.

Effects of prolonged oral treatment with N-fluoren-4-ylacetohydroxamic acid on rat liver fine structure.

Inbred male Leeds strain rats were given a diet containing 0.05% N-fluoren-4-ylacetohydroxamic acid for up to 7 months. A modified method for the synthesis of this compound is described.

Resolution of (+/-)-propranolol.

Two improvements in propranolol resolution were developed. Both the (+)- and (-)-di-(p-toluoyl)tartaric acids were used as the resolving agents. This procedure reduced the number of crystallizations needed to obtain a pure product.

The carcinogenicity of fluorenylhydroxamic acids and N-acetoxy-N-fluorenylacetamides for the rat as related to the reactivity of the esters toward nucleophiles.

In extension of previous work indicating that the carcinogenicity of isomeric fluorenylhydroxamic acids depends on the point of attachment of the nitrogen atom on the fluorene system, the carcinogenicities of N-hydroxy-3-fluorenylacetamide and of N-hydroxy-4-fluorenylacetamide were evaluated in male and female Sprague-Dawley rats by several routes of administration and were compared with the carcinogenicity of N-hydroxy-2-fluorenylacetamide. The earlier observation that N-hydroxy-3-fluorenylacetamide is a specific mamary carcinogen was confirmed. N-Hydroxy-4-fluorenylacetamide was only marginally carcinogenic.