摘要:

AbstractThe stability of L‐[2‐18F]‐fluorophenylalanine (2‐[18F]‐Phe) was compared with that of natural amino acid, L‐[2,6‐3H]‐Phenylalanine (2,6‐[3H]‐Phe). The mixture of 2‐[18F]‐ and 2,6‐[3H]‐Phe was injected to Wistar rats. The separated arterial plasma was followed by acid treatment and chromatographical analysis. The plasma [18F]‐ and [3H]‐radioactivities decreased with the time and showed the lowest value at 20 min after injection. After that, [3H]‐radioactivity increased significantly up to 60 min, while [18F] ‐ radioactivity remained at the lowest level. The [3H]‐ and [18F] ‐ radioactive macromolecules appeared in the plasma at 10 and 20 min, respectively. In the acid soluble fractions of the plasma and the brain at 60 min, more than 80% of [18F] ‐ radioactivity existed as 2‐[18F] ‐ Phe, while 2,6 ‐ [3H] ‐ Phe was less than 15%. These data suggest the slow metabolism of 2 ‐ [18F] ‐ Phe as compared with that of natural Phe. In conclusion, 2 ‐ [18F] ‐ Phe is suitable to the compartment analysis using positron emission tomography especially at the process of amino acid transport to the brain due to i

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270303

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe catalytic debromination of 2,2,6ß‐tribromo‐cholest‐4‐en‐3‐one with tritium gas (T2) yields tritium‐labelled cholest‐4‐en‐3‐one of high specific activity. The most favourable reaction parameters are reported. Using tritium‐hydrogen (TH) gas mixtures the labelling reactions are accompanied by three kinetic isotope effects the importan

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270304

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe phospholipids, ALP and Thio‐ALP, are non‐hydrolyzable analogues of platelet activating factor (PAF). Interest in ALP and thio‐ALP centers upon their activity as potential antineo‐plastic agents. A variety of mechanisms of action have been attributed to these compounds including inhibition of a phospholipid cofactor of a phospholipid sensitive Ca+2‐dependent protein kinase. Thio‐ALP is at least as active as a growth inhibitor of the HL‐60 promyelocytic leukemic cell line as is ALP‐the most active reference analogue reported in the literature and is approximately twice as active against the BG‐1 and BG‐3 human ovarian carcinoma cell lines. To aid in further biochemical studies, we report the synthesis of high specific activity tritium labelled ALP and thio‐ALP. These products were obtained by palladium catalyzed reduction of 1‐0‐octadecenyl and l‐S‐hexadecenyl precursors w

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270305

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe radiochemical synthesis and purification of [18F] N‐(1‐(2‐thienyl)‐cyclohexyl)‐4‐fluoropiperidine [[18F]FTCP]is reported. [18F]FTCP is prepared by [18F] fluoride displacement on a mesylate precursor. The crude products are treated with borane to aid in the removal of an elimination product. Purification of the radiopharmaceutical involves a short silica gel BOND ELUT column and subsequently reverse phase HPLC. The final product has high chemical and radiochemical purity with the radiochemical yield optimized at nearly 30 percent (corrected

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270306

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractAdinazolam mesylate labeled with stable isotopes was synthesized for conducting bioavailability studies. Adinazolam labeled uniformly with carbon‐13,>99% enrichment, in the unsubstituted phenyl ring was prepared for administration as drug. In addition, adinazolam was also dual‐labeled with carbon‐13, as in the drug, and with deuterium, six atoms per molecule, in the N‐methyl groups. The double‐labeled material was prepared for use as an internal standard in the mass spectral assay procedure to be employed in

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270307

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

Abstractd,l‐Glaucine 1.5 H3PO4, is a non‐narcotic antitussive for which a sample of carbon‐13 labelled material was required for metabolism studies in humans. The sample of 99% enrichedd,l‐6a‐13C‐glaucine 1.5 H3PO4was prepared in 7 steps in 36% overall yield starting with purchased 99% enriched 1‐13C‐papaverine. The papaverine was N‐methylated with methyl iodide and the resulting methiodide reduced tod,l‐1‐13C‐laudanosine with sodium borohydride. The laudanosine was O‐demethylated with 48% HBr and cyclized tod,l‐6a‐13C‐1,2,9,10‐tetrahydroxyaporphine (THA) using aqueous ferric chloride/sodium acetate and isolated as the hydrochloride salt (THA ± HCl). The THA ± HCl was converted to the free base and remethylated with phenyltrimethylammonium hydroxide. The resultingd,l‐6a‐13C‐glaucine was purified by column chromatography and isolated as the hydrobromide salt. Thed,l‐6a‐13C‐glaucine 1.5 H3PO4was obtained by conversion of the hydrobromide to the free base an

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270308

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractStrychnine (1a) was reduced with tritium gasviaheterogeneous catalysis to yield [21, 22‐3H] dihydrostrychnine (2b) at 31 Ci/mmol andviahomogeneous catalysis to yield2bat 50 Ci/mmol. [2‐3H] Strychnine (1b) at 25 Ci/mmol was prepared by the catalytic reductive tritiation of 2‐iodostrychnine (4). Other polyhalo strychnine analogues were synthesized in an attempt to prepare [3H] strychnine at even higher specific act

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270309

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractDimethyl 3,4,5,6‐[2H4]‐2‐oxoheptylphosphonate (1a) was conveniently prepared in two steps from ethyl sorbate and used in a total synthesis of low‐blank (⩽ 0.2%2Ho) 16,17,18,19‐[2H4]‐prostaglandin D2(2a). The required allylic alcohol 15S‐8was isolated by fractional crystallisation of the mixture of R/S epimers and then transformed to a key intermediate, 15S‐silyloxy compound10, by regiocontrolled monosi

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270310

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractSK&F 94836, a selective PDE III inhibitor is a positive inotropic agent with vasodilator activity. The syntheses of (‐)‐[N‐methyl‐14C]SK&F 94836, (+)‐[N‐methyl‐14C]SK&F 94836 and [carbonyl‐14C] SK&F 94836 are described. The racemate, labelled in the dihydropyridazinone heterocycle was obtained in 24.6% overall yield from K[14C]CN. The chiral compounds were radiolabelled by reacting a resolved precursor with [

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270311

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractL‐[35S]Homocysteine thiolactone has been synthesized by demethylation of L‐[35S]Methionine with sodium in liquid ammonia and subsequent lactonisation in acid solution. The radiochemical yield of the carrier added synthesis was in the range of 45 to 50 % with a radiochemical purity higher than 9

ISSN:0362-4803    

DOI:10.1002/jlcr.2580270312

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY