摘要:

AbstractPorphobilinogen‐11‐13C was prepared by using benzyl 3‐(β‐methoxycarbonylethyl)‐4‐ (methoxycarbonylmethyl)‐2‐pyrrolecarboxylate as a starting material. A Vilsmeier‐Haak formylation with N,N′‐dimethylform‐13C‐amide gave the 2‐formylpyrrole, which was transformed into its oxime, and the latter was hydrogenated to the hydrochioride of 5‐carboxyporphobilinogen dimethyl ester. The hydrochloride cyclized to 5‐carboxyporphobilinogen lactam at pH 9, and the latter was first decarboxylated and then sapon

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190102

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractEthanolamine‐2‐14C was prepared by the reduction of benzyloxycarbonyl‐glycine‐1‐14C methyl ester. The reduction was carried out with calcium borohydride and the protecting group was removed by hydro

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190103

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

Abstract1‐[2‐hydroxy‐4‐(3‐sulfo‐1‐propyloxy)‐phenyl]‐3‐ ‐(3‐hydroxy‐4‐methoxyphenyl)‐propan‐1‐one sodium salt labelled with14C at its carbonyl group (1) was synthetized starting from sodium acetate‐1‐14C through acetyl chloride‐1‐14C, resacetophenone‐carbonyl‐14C (2), 2‐hydroxy‐4‐(3‐sulfo‐1‐propyloxy)‐acetophenone‐carbonyl‐14C sodium salt (3) and 1‐[2‐hydroxy‐4‐(3‐sulfo‐

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190104

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractMethylcis,cis‐,trans,cis‐,cis,trans‐, andtrans,trans‐12,15‐octadecadienoates‐9,10‐d2were prepared by the Wittig Reaction betweencis‐ ortrans‐3‐hexenyltriphenylphosphonium bromide and methyl 12‐oxododecanoate‐9,10‐d2with butyl lithium in ethyl ether. At room temperature, the Wittig Reaction gave a product mixture with 80‐85%cisgeometry in the double bond formed. When the reaction was run at −40°C, followed by protonation with methanol and slow warm‐up to room temperature, the product mixture had 60‐65%transgeometry in the double bond generated. Mixtures of thecis,cisandtrans,cisand of thecis,transandtrans,transisomers were separated by partial silver resin chromatography, and the individual pure fatty esters were converted to the triglycerides through the respective acid chlorides. Melting points and nuclear magnetic reson

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190105

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe preparation of tritium labelled catechol by catalytic reduction of tetrabromocatechol is described. Recrystallization of catechol (U‐3H) after silica gel column purification gave 68% yield of the desired product with 98% purity as assayed by high performance liquid chromatograph

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190106

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractNuclear decay of C3H4in the presence of gaseous furan represents a simple and convenient synthetic route to carrier‐free multitritiated 3‐methyl‐ and 2‐methyl‐furan. Their application for biological studies appears particularly promising, on account of the favourable characteristics of the followed synthetic

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190107

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractDeuterium labeled forms of 5α‐androst‐16‐en‐3‐one, 3α‐hydroxy‐5α‐androst‐16‐ene, 3β‐hydroxy‐5α‐androst‐16‐ene, 3β‐hydroxy‐5, 16‐androstadiene and 4, 16‐androstadien‐3‐one were prepared to serve as internal standards in quantitative analysis of C19‐Δ16steroids by mass spectrometric reverse isotope dilution. In general, the methods used employed deuterium exchange of activated hydrogens adjacent to carbonyl carbons followed by reaction steps which isolated the newly incorporated deuterium. Removal of any remaining exchangeable deute

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190108

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

Abstract11C‐Labelled benzene derivatives were prepared catalytically by trimerizing acetylene‐11C with acetylene and propyne carriers over 1.5 grams of silica‐alumina support activated by potassium chromate (0.2% by weight). Optimized yields of the11C‐labelled aromatics were obtained when the reactants were exposed to the catalyst for 10 minutes at 24°C. A minimum addition of 50 μmole of alkyne carrier was necessary before the trimerization proceeded to give appreciable yields of11C‐labelled aromatics. In the competitive trimerization of acetylene‐11C with acetylene and propyne carriers, three11C‐labelled aromatic products were generated: benzene, toluene, and xylene. From these studies acetylene was observed to be 1.6 times more reactive than propyne. In addition, the observed distribution of11C‐labelled xylenes (3.4% ortho, 10.6% meta, and 86% para) indicates an apparent regiospecificity in the trimerization of11C‐ace

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190109

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of14C‐labelled crotamiton, which is a fungicide, an insecticide as well as a scabicide is described. Starting from 2‐bromonitrobenzene and Cu14CN,o‐toluidine, labelled with14C at the methyl group was prepared by the following sequence of reactions: NO2‐C6H4‐Br → NO2‐C6H4‐14CN → NO2‐C6H4‐14COOH → NO2‐C6H4‐14CH2OH → NO2‐C6H4‐14CH2Br → NH2‐C6H4‐14CH3. Labelledo‐toluidine was then heated with crotonic anhydride to give crotonic acido‐toluidide which was then ethylated by treatment with sodium hydride and

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190110

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractOptically active α‐deuterated serine dipeptide active ester derivatives were prepared to study the racemization mechanism. N‐Acetyl‐O‐benzyl‐DL‐serine,1, was converted to 5(4H)‐oxazolone2and deuterated with CH3‐COOD in α‐position. 5(42H)‐Oxazolone3was converted to Z‐(α2H)‐L‐Ser(Bzl)‐OHThe following abbreviations are used: benzyloxycarbonyl = Z; tert‐butyloxycarbonyl = Boc; benzyl = Bzl; pentachlorophenyl = Pcp; dicyclohexylcarbodiimide = DCC; dicyclohexylurea = DCU, tetrahydrofuran = PHF; thin layer chromatography = TLC7, after opening the 5(42H)‐oxazolone ring with D2O, removal of the N‐acetyl group, treatment with carbobenzoxy chloride and resolution with (+)‐α‐phenylethylamine. Pentachlorophenyl ester8of7was converted to Z‐Gly‐(α2H)‐L‐Ser(Bzl)‐OPcp,10, after removal of carbobenzoxy group by catalytic hydrogenation. The deuterium content of t

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190111

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY