摘要:

AbstractThe synthesis of 1,1,3,3‐tetraethoxypropane‐1,2,3‐14C3from uniformly labeled paraldehyde is described. The synthesis involves three steps and proceeds in an overall yield of 25%. The final product is greater than 95% radiochemically pure and it is stable indefinitely when stored as thoroughly degassed benzene solutions. Hydrolysis of radiolabeled tetraethoxypropane occurs in moderate yields to form malondialdehyde‐1,2,3‐14C3(1,3 propanedial‐1,2,3‐14C3) which is isolated and stored as the sodium salt. One of the intermediates in the synthesis of tetraethoxypropane is ethyl vinyl‐[1,2‐14C2] ether, which is isolable in 50% overall yield from paraldehyde. The widespread utilization of ethyl vinyl ether in organic synthesis suggests that the radiolabeled material should provide an entry to a large number of specifically [14C]

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170502

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractTritium, deuterium, and carbon‐13 labeled cycloheximide were prepared through fermentation ofStreptomyces griseusin the presence of S‐methyl labeled L‐methionine. Cycloheximide‐3H of specific activity 4.96 mCi/mg (1.40 Ci/mmol) was obtained in 25% overall radiochemical yield. Nuclear magnetic resonance and mass spectral analyses of the deuterium and carbon‐13 labeled products showed that isotope incorporation occurred virtually exclusively in the two methyl groups in cycloheximide, with negligible (<5%) incorporation in the rest of the molecule. Furthermore, deuterated species contained either three or six deuterium atoms, indicating that the methyl groups were transferred intact from L‐methionine. Also, the two methyl groups in cycloheximide were of equal isotope enrichment. The overall enrichment achieved in the methyl groups was 55% and 45%, respectively, in the deuterium and carbon‐13 labe

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170503

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

Abstract17β‐Hydroxy‐[1ξ,2ξ‐3H2]4,6‐androstadien‐3‐one was prepared by the selective reduction of 17β‐hydroxy‐1,4,6‐androstatrien‐3‐one in benzene with tritium over 5% palladium on carbon. After purification by thin layer chromatography and high pressure liquid chromatography, the specific activity was at least 37 Ci/mmol, and the radiochemical pu

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170504

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractThe enantiomers of MK‐196, (6,7‐dichloro‐2‐methyl‐1‐oxo‐2‐phenyl‐5‐indanyloxy)‐acetic acid, and the 2‐(4‐hydroxyphenyl) derivative, the major metabolite of MK‐196, were resolved by classical methods using α‐methylbenzylamine salts, and converted to the corresponding, enantiomerically pure (indanyloxy)acetic acids‐α‐14C by facile ether cleavage with pyridine hydrochloride to the 5‐indanols, selective O‐re‐alkylation with methyl bromoac

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170505

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

Abstract13C‐Labelled (η6‐benzene)tricarbonylchromium(0), BzCr(13CO)3(Bz = η6‐C6H6), has been prepared in about 50% yield with greater than 90 atom%13C‐enrichment by a multistep, photochemically‐induced exchange of the three carbonyl groups in BzCr(CO)3with13CO. The syntheses of the closely related,13CO‐labelled, thiocarbonyl and selenocarbonyl derivatives, BzCr(13CO)2(CX) (X = S, Se), from BzCr(13CO)3are a

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170506

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractTritium labelled (17‐3H) 16α, 17α‐epoxy‐androst‐4‐en‐3‐one and 16α, 17α‐epoxy‐estra‐1,3,5(10)‐trien‐3‐ol have been prepared on a large scale (200‐300 mg amounts) with efficient (i.e. activity of product exactly predictable) introduction of label. The preparative method is very inexpensive, since the tritium derives from tritiated water, the steroid starting materials are readily available, and high y

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170507

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractAromatic astatine compounds can be prepared under mild conditions in high yields by reaction of astatine with aromatic mercury compounds.Compared to direct electrophilic astatination this procedure is an easy and clean method for the introduction of astatine in aromatic compounds.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170508

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractChloroquine can be iodinated with radioactive iodine in radiochemical yields 60‐75% with chloramine‐T or H2O2/lactoperoxidase. With both methods a rather complex mixture of labelled products is formed. The yield and ratios of the labelled products depend upon the chloroquine‐concentration, the amount of carrier iodide present and in the case of the chloramine‐T method, the chloramine‐T concentration. With the chloramine‐T method the main product is 3‐iodochloroquine, with H2O2/lactoperoxidase an unidentified iodinated chloroquine‐derivative, probably a dimer, is the main labelled product. With chloramine‐T products such as 3‐chlorochloroquine and deethylchloroquine are for

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170509

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractNucleophilic exchange of 5′‐iodo‐Δ8‐THC and sodium iodide‐125 afforded 5′‐iodo‐125I‐Δ8THC with a maximum specific activity of 42 Ci/mmole. The specific activity could be increased to at least 100 Ci/mmole by iodide‐125 displacement of the corresponding 5′‐tosylate. A hapten 5′‐carboxy‐14C‐Δ9‐THC, for use in conjunction with this radioligand,

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170510

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY

摘要:

AbstractNefopam hydrochloride (I), an analgesic agent, was labelled with carbon‐13 at C‐1,3,4 and 6 positions for metabolic studies. The starting materials for the synthesis included commercially available phthalic acid‐carboxyl‐13C1(II) and 2‐methylaminoethyl‐1,2‐13C2alcohol. The extent of isotope enrichment was determined by nuclear magnetic resonance and mass spectroscopy. The overall yield of I was 34% from phthalic acid

ISSN:0362-4803    

DOI:10.1002/jlcr.2580170511

出版商:John Wiley&Sons, Ltd.    

年代:1980

数据来源: WILEY