摘要:

AbstractClassical phospholipids syntheses were selected and adapted to the preparation of natural glycerophospholipids labelled with carbon 14 in the acyl moiety. 1,2‐(14C) diacyl‐3‐bromo sn‐glycerol was the starting material.Saturated14C‐phosphatidyl‐ethanolamine, choline and serine were obtained in 30 %, 25 % and 11 % yields relative to the14C‐fatty acid, by condensation of a suitably protected amino‐alcohol with a (14C‐diacyl) phosphatidic acid in presence of triisopropyl‐benzenesulfonyl‐chloride followed by deprotection of the amino group.The synthesis of unsaturated (or mixed)14C phosphatidyl ethanolamine was achieved, with a 28 % yield, by condensation of the14C‐diacyl‐bromoglycerol with the silver salt of the N‐trityl aminoethyl and benzyl diester of phosphoric acid a

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180902

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe one‐step synthesis of14C‐methyl(acetoxymethyl)nitrosamine (14C‐DMN‐OAc) of high specific activity is described. The product was shown to decompose by hydrolysis, as reported previously for the unlabelled material, and by self‐radiolysis, a process which occurred even in methylene chloride solution at high specific activities. Both modes of decomposition led to disappearance of label from the solution, at least partly by sorption to the glass storage vessel. Thin‐layer chromatography proved less suitable for resolving the decomposition products than radio‐gas chromatography. Labelled carbon atoms were found to the extent of only 1% in the formaldehyde produced on esterase hydrolysis of14C‐DMN‐OAc, showing that scrambling during the synthesis was not extensive. Storage of aqueous solutions for biological work was best accomplished in frozen aqueous so

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180903

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe synthesis of14C‐labelled metoprolol, a new antihypertensive drug is described. Starting fromp‐bromoanisole and14CO2,14C‐labelledp‐methoxyphenylethyl alcohol was prepared by the following sequence of reactions: MeO‐C6H4‐Br→ MeO‐C6H4‐14COOH→ MeO‐C6H4‐14CH2OH→ MeO‐C6H4‐14CH2Cl→ MeO‐C6H4‐14CH2‐CN→ MeO‐C6H4‐14CH2‐COOH → MeO‐C6H4‐14CH2‐CH2OH. Heating with 47% HBr gave [14C]‐p‐hydroxyphenylethyl bromide which on treatment with methanol under alkaline condition was converted into [14C]‐p‐hydroxyphenylethyl methyl ether. Reaction with ep

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180904

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

Abstract(S)‐α‐Cyano‐3‐phenoxybenzyl (S)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate (fenvalerate Aα), an optically active insecticide, was labelled with carbon‐14 individually at the benzyl ring (1a) and the chlorophenyl ring (1b) for use in metabolic studies. Ullmann reaction of 3‐methylphenol‐14C6(2) with bromobenzene followed by oxygen oxidation gave 3‐phenoxybenzoic‐14C6acid (4). Reduction of4followed by potassium dichromate oxidation of the alcohol (5) gave 3‐phenoxybenzaldehyde‐14C6(6). Condensation of6with (S)‐2‐(4‐chlorophenyl)‐3‐methylbutanoyl chloride and sodium cyanide afforded fenvalerate A‐(benzyl‐14C6), which on optical resolution gave1ain 29% yield from2. Isopropylation of 4‐chlorophenyl‐14C6‐acetonitrile (9) followed by hydrolysis gave 2‐(4‐chlorophenyl‐14C6)‐3‐methylbutyric acid which on optical resolution gave the (S)‐acid (12). Esterification of the acid with α‐cyano‐3‐phenoxybenzyl bromide yielded fe

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180905

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractIn present work the syntheses of derivatives of 9α, 11α tritium labelled estradiols are described. Estron, estradiol, 17α‐ethynylestradiol and its 3‐isopropylsulfonyl ester were synthesized with high specific activity. Comparing the specific activities of all products it was obvious that tritium is exchanged in considerable amount in the strongly alkaline medium of ethynylation step. We believe that this exchange is attributed to tritium in benzylic pos

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180906

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractAcetyl‐3,5‐Br‐82‐dibromosalicylic acid (dibromoaspirin) was synthesized by radiobromination of salicylic acid to yield 3,5‐dibromosalicylic acid, followed by acetylation of this intermediate. Biodistribution studies in mice with and without a neuroblastoma showed that the tumor/blood radioactivity ratio was low (0.3 at one hour). Thin layer chromatography of urine indicated that only 20 to 30% of the radioactivity corresponded to dibromoaspirin. Studies of rabbits with inflammatory lesions showed that the inflammatory/normal tissue uptake ratio was 1.0 to 1.9. The RBC/plasma ratio was less than 0.5. Low uptake of radioactivity was likely due to rapid dehalogenatio

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180907

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe applicability of chloramine‐T (CAT) was examined for “no‐carrier‐added” labelling of aromatic compounds with the short‐lived isotopes bromine‐77 (T1/2= 56 h) and bromine‐75 (T1/2= 98 min). In aqueous solution the optimum reaction conditions with respect to pH, concentration of CAT, reaction time and added brominecarrier were determined using tyrosine as a model substrate. Highest radiochemical yields (>85%) were obtained at pH 1 within a few seconds at a CAT concentration of 10−3M. At pH 7 a maximum radiochemical yield of 65% was achieved with 10−2M after 2.5 minutes. Studies with some model peptides showed that only the tyrosyl residues were brominated and similar yields were obtained as in free tyrosine. Some aromatic molecules such as α‐methyl‐tyrosine, phenylalanine, uracil, cytosine, and phenol were radiobrominated by the CAT method with yields up to 90%. Separation and identification of the labelled products were achieved by means of radio high performan

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180908

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe N‐ethylpiperidine salt of [3H]penicillin G (31 Ci/mmole) was prepared and stored in acetone solution at −15°. The radiochemical purity, as determined by reverse isotope dilution assay, decreased about 12% over a period of one month, less than that expected for an aqueous solu

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180909

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractDeuteration of disopyramide, 4‐diisopropylamino‐2‐(2‐pyridyl)‐2‐phenylbutyramide, was accomplished in an excess of2H2SO4at 125–135°C. Incorporation of 2‐4 atoms of deuterium occurs with 65% recovery of disopyramide. At higher temperatures (150°C) greater incorporation of deuterium occurs, but substantial decomposition reduces the recovery of di

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180910

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe synthesis and radioiodide exchange labelling of 14‐iodo‐9‐tetradecynoic acid (1), a potential suicide inhibitor of acyl‐CoA dehydrogenase or enoyl‐CoA isomerase, is presented. Tissue distribution data in dogs are

ISSN:0362-4803    

DOI:10.1002/jlcr.2580180911

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY