摘要:

AbstractA novel method for a one‐step on‐line production of no carrier added11CH3I is described. The method makes use of recoil reactions of11C‐atoms, produced via the14N(p, α)11C‐process in a gaseous N2‐HI flow target system. The radiochemical yield of11CH3I under optimized conditions is 25 %. Separation from11CH4which is formed with a radiochemical yield of 45 % and from high boiling by‐products is readily achieved by washing and trapping procedures. Up to 90 mCi of pure11CH3I have been produced with specific activities of about 300 Ci/mmol after a 40 minute col

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181102

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe possibilities of tritium labelling of tofizopam (1) at high specific activity were investigated. Two methods, one by isotopic exchange, and one by catalysed halogen‐tritium replacement were developed. The latter was found to be more rational, and1specifically labelled with tritium at a specific activity of 12 Ci/mmole was prepared by applying this route. An attempted labelling by catalysed multiple bond reduction with tritium is also describe

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181103

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractIndicineN‐oxide, an antitumor agent possessing an unusual type of potential alkylating capacity, was recently selected for clinical trial. Radioactive‐labelled indicineN‐oxide was sought for studies of its biological properties relating to antitumor activity and toxicity. Available indicineN‐oxide was reduced to indicine, and the alkaloid ester was hydrolyzed to its component compounds, retronecine and (−)‐trachelanthic acid. The radioactive label was then introduced into the hydroxymethyl grouping of retronecine by a previously reported procedure involving oxidation of retronecine to methyl 1,2‐dehydro‐7β‐hydroxy‐8α‐pyrrolizidine‐1‐carboxylate followed by reduction of the methoxycarbonyl grouping with LiAl3H4. Recombination of the alcohol and the carboxylic acid, a heretofore challenging problem in syntheses of pyrrolizidine alkaloid esters, was achieved using an adaptation of the mild esterification procedure recently reported by Hassner and Alexanian. By this method, indicine was obtained following reaction of retronecine, the isopropylidene derivative of (−)‐trachelanthic acid, andN,N′‐dicyclohexylcarbodiimide in the presence of 4‐(dimethylamino)pyridine in toluene. Tritium‐labelled indicine thus formed was then treated withm‐chloroperoxybenz

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181104

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractA synthesis of oleic‐1‐13C acid and its conversion to triolein‐1′,1″,1″′‐13C3are described. 9‐Octadecynenitrile‐1‐13C was prepared from 1‐bromo‐8‐heptadecyne and sodium cyanide‐13C. Hydrolysis afforded stearolic‐1‐13C acid, which was reduced to oleic‐1‐13C acid by the action of disiamylborane on methyl stearolate‐1‐13C. Hydrogenation of stearolic acid in the presence of Lindlar's catalyst was also investigated. Condensation of glycerol and oleic‐1‐13C acid to give triolein‐1′,1″,1″′‐13C3was effected with dicyclohexylcarbodiimide and 4‐dimethylaminopyridine. The ov

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181105

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractA facile synthesis for the efficient incorporation of14C or13C into trisubstituted furan compounds has been elaborated. 3‐Methyl‐4,5,6,7‐tetrahydrobenzofuran was prepared in five steps from methyl‐ and ethyl‐2‐oxo‐1 cyclohexanecarboxylate with overall yield of 65%. Radioactive label was nearly quantitatively incorporated. One new compound,7, has been prepared in elaborating the synth

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181106

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe synthesis of a [9α, 11α‐]‐tritium‐labelled new steroid with interceptive — post‐coital antifertility — activity, 3‐methoxy‐14β, 15β‐methylene‐estra‐1,3,5(10)‐triene‐17β‐ol, starting with the catalytic tritiation of 3‐methoxy‐estra‐1,3,5(10), 9(11)‐tetraene‐14α, 17β‐diol, is described.3‐Methoxy‐14β, 15β‐methylene‐[9α, 11α‐3H]‐estra‐1,3,5(10)‐triene‐17β‐ol was obtained in a four‐step synthesis with high specific activity (3,8 Ci/mmole) and radiochemica

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181107

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractIsotopic exchange of benzylic hydrogens in α‐ and β‐alkyl side‐chains of pyrylium salts occurs readily by heating in deuterium oxide at normal pressure. As β‐hydrogens exchange faster than α‐hydrogens, one may obtain selective (about 90 % isotopic purity) β‐ or α‐deuteriation of side‐chains by direct or reverse isotope exchange. The deuteriated pyrylium salts are converted by aqueous ammonia into the corresponding pyridines without loss of deuterium. Examples presented are : 2,4,6‐tri‐(d3‐methyl)‐, 2,6‐di‐(d3‐methyl)‐4‐methyl‐, 2,6‐dimethyl‐4‐(d3‐methyl)‐, 2,6,‐di‐(d3‐methyl)‐3,5‐dimethyl‐, 2,4,6‐tri‐(d3‐methyl)‐3,5‐di‐methyl‐, 2,6‐di‐(α‐d2‐ethyl)‐4‐(d3‐methyl)‐, 2,6

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181108

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractProcedures for the preparation of trifluoperazine with two, four and six deuterium atoms are described. Deuterium was introduced in the propylpiperazine side chain by treatment of the appropriate amide with lithium aluminium deuteride. The isotopic purity of the products was greater than 96.2%.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181109

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

Abstracttrans‐4‐Octene‐1,1,1‐2H3; −2,2‐2H2; −3,3‐2H2and −4‐2H1have been synthesized. The electron impact mass spectra and isotopic enrichment of these compounds have been measur

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181110

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractIt is often necessary to obtain certain11C radiopharmaceuticals with a high specific activity (>1000 Ci/mmole), especially when these are intended for medical purposes and are either toxic or used for “in vivo” specific receptor binding studies. The amounts of labelling agent must be very small (concentrations often below to 10−3M) and some synthesis are difficult or impossible under these conditions.—This article shows how the specific activitry of the labelling agent A 1*affects the synthesis yield of the radiopharmaceutical A 1*′ in the reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ v_1 {\rm A}_{\rm 1}^{\rm *} + v_2 {\rm A}_{\rm 2} \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} v'_1 {\rm A'}_{\rm 1} ^* + v'_2 {\rm A'}_{\rm 2} $$\end{document}—A specific activity increase can improve, reduce or have no effect on the yield according to the respective valuse ofV1,V2,V′1,V′2.—Different ways to shift an epuilibrium unfavourabel to labelling are also given : reaction temperature, concentrations, addition of starting products, removal of final products.—The reaction kinetics are important since the half‐life of carbon 11 is 20 mn, but this parameter is a complex function of concentrations which can only be detemined by experiment. It seems however that in special cases the percentage of radioactivity incorporated in a given times is imdependent of specific activity.—The effect of impurities, which can be present in concentration of the same order of magnitude as those of the labelling agent is also discussed.—Each thereticl development is illustrated by concrete examples studied in the laboratory.—The conclusion is that theoretically it should not be impossible to synthesize strictly carrier‐free11C radiopharmaceuticals in certain favourable cases (if it were known how to prepare su

ISSN:0362-4803    

DOI:10.1002/jlcr.2580181111

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY