AbstractThe catalytic reduction of (+)‐cismethrin 1, a synthetic pyrethroid, with tritium gas in various solvents and in presence of different catalysts was studied. The best result was obtained with 5% Pd‐ BaSO4 catalyst in methanol giving rise to 3H‐5‐benzyl‐3‐furylmethyl (+)‐cis‐3‐isobutyl‐2,2‐dimethylcylopropane carboxylate 2 with a specific activity of 98 Ci. mmol−1 (3626 GBq. mmol−1). The incorporation of tritium was verified by H‐NMR and MS analyses.

Phenobarbital-induced rat liver homogenate and microsomes were used to study covalent binding of l4C-labelled (at the alcohol moiety) cismethrin, 14C-labelled (at the alcohol and acid moieties) cypermethrin, and 14C-labelled (at the alcohol and acid moieties) deltamethrin. Covalent binding was dependent on pyrethroid concentration. With liver homogenate, inhibition of esterases by tetraethylpyrophosphate and of mitochondrial respiration by rotenone or potassium cyanide only slightly altered the covalent binding level. With microsomes, inhibition of cytochrome P-450 and mixed function oxidases by carbon monoxide and piperonyl butoxide reduced the covalent binding so far as to be nearly absent. Eighty percent inhibition of epoxide hydrolase decreased the covalent binding by 50%. The comparison of data between alcohol and acid labelling of the same pyrethroid suggested that, in vitro, the whole molecule is bound to proteins and that hydrolysis can occur afterwards. The experiments stress the role of cytochrome P-450-dependent monoxygenases in the covalent binding process.

AbstractSynthesis and chromatographic separation of (E) and (Z) isomers of (ring‐U‐14C) hexanal phenylhydrazone 2 : (ring‐U‐14C) phenylhydrazine hydrochloride 1 was synthesized from labelled aniline hydrochloride, and purification was accomplished by reverse phase low pressure liquid chromatrography. The crude free base of 1 was condensed with hexanal to give a mixture of (E) and (Z) isomers of 2. The conditions for their separation by reverse phase HPLC were optimized on an analytical column and then used for the preparative work which was the most effective and fastest method.Structure and configuration of (E) and (Z) isomers of (ring‐U‐14C) hexanal phenylhydrazone (SA = 13.3 mCi/mmol) were proven by 1H‐NMR and mass spectroscopy.

AbstractProcedures are described for the synthesis of the following metabolites of deltamethrin, the pyrethroid insecticide: 3‐phenoxy (carboxyl‐14C) benzoic acid, 3‐(2′‐hydroxyphenoxy) (carboxyl‐14C) benzoic acid and the corresponding 3‐phenoxybenzyl alcohols, specific activity = 47–57 mCi/mmol.

Abstract(tetramethyl‐ 14C)Pentamethylmelamine 6, a new antitumor agent, was prepared by a three‐step synthesis starting with (14C)CH3I. Toluene‐p‐sulphonamide was condensed with (14C)CH3I to give labelled NN‐dimethyltoluene‐p‐sulphonamide. 14C‐labelled dimethylamine was released from the dimethylamide by the action of 48% HBr and NaOH, then reacted with 2,4‐dichloro‐6‐methylamino‐1,3,5‐triazine to afford 6. After purification by silicagel column chromatography 6 was obtained in a 8.5% yield from (14C)CH3I and a radiochemical purity of 99%, specific activity : 78.5 mCi/mmole.

Abstractdl‐Methadone was resolved by crystallization of its ammonium d‐ α ‐ bromocamphor‐ π ‐ sulfonate salt to give d‐methadone. The latter in ethyl acetate solution was reduced with tritium gas to 1‐ α ‐methadol 3H in presence of Adams platinum oxide at normal temperature and pressure. Acetylation of 1‐ α ‐carbinol hydrochloride by means of acetyl chloride afforded 1‐ α ‐acetylmethadol 3H, specific activity : 20 Ci/mMole. The positions and extent of tritium labelling were determined by 3H NMR spectroscopy.

Abstract(ring‐4,6‐14C) Pentamethylmelamine (14C‐PMM), a new antitumor agent, was prepared from barium (14C) carbonate by a 6 step synthesis. (14CN) Dimethylcyanamide, prepared from sodium (14C) cyanide with 71% yield and treated with phosgene in the presence of hydrogen chloride, was cyclized to (ring‐4,6‐14C)‐2‐chloro‐4,6‐bis (dimethylamino)‐s‐triazine. The latter was purified by silicagel low pressure liquid chromatography (15% yield based on nitrile) and condensed with monomethylamine to give 14C‐PMM. After purification 14C‐PMM was obtained with 91% yield, specific activity = 38 mCi/mMole. The mechanism of the reaction of nitrile with phosgene was discussed.

AbstractCarbonation with 14CO2 of penylethynyl‐lithium has given rise to (carboxyl‐14C) phenylpropiolic acid with 75 % yield based on 14CO2. The latter condensed with 2‐naphthol by treating with polyphosphoric acid afforded (4‐14C) β‐naphthoflavone, purified by silicagel low pressure liquid chromatography; 22 % overall yield based on 14CO2, SA = 13 mCi/mM. Similar run of 2‐(8‐14C) naphthol with phenylpropiolic acid gave (5‐ 14C) β‐naphthoflavone; 28 % yield based on radioactive 2‐naphthol, SA = 7.2 mCi/mM.