摘要:

Abstract2‐Aminopyridine is a versatile building block in the preparation of certain heterocycles such as imidazo[1,2‐a]‐pyridines, pyrido[1,2‐a]‐pyrimidin‐ones and substituted derivatives there‐of.14C‐labelled 2‐aminopyridine was synthesized as follows: potassium‐[14C]cyanide (I) was reacted with epichlorohydrin (II) to give 3‐hydroxy‐[1,5‐14C2]pyridine (IV) which was then reductively dehalogenated to the 2,6‐14C2‐labelled title compound (V) in 36 % overall chemical and radio‐chemical yield, based upon I. The product was radiochemically pure (99.1 %) according to high‐performance liquid chromatography and thin‐layer chromatography, and had a

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240202

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe syntheses of racemic [3‐11C]‐labelled alanine, 2‐amino‐butyric acid, norvaline, norleucine, leucine and phenyl‐alanine are reported. The reaction were performed by a phase‐transfer alkylation reaction onN‐(diphenylmethylene)‐glycinetert‐butyl ester with the appropriate11C‐alkyl iodides followed by acidic hydrolysis and the labelled amino acids were obtained in 10‐55 % radiochemical yield. L‐[3‐11C]‐Alanine and L‐[3‐11C]phenylalanine were obtained in 99 % enantiomeric excess after treatment of the corresponding racemic mixture by D‐amino acid oxidase immobilized on glutaral‐dehyde‐activated glass beads.In a typical run starting with 120 mCi [11C]carbon dioxide, 25 mCi [1‐11C]benzyl iodide was prepared and used to give 6 mCi of DL‐[3‐11C]phenylalanine within 50 minutes. Following treatment with D‐amino acid oxidase, 0.3 mCi of L‐[3‐11C]phenylalanine was obtained

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240203

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractSKF 82526 (6‐chloro‐7,8‐dihydroxy‐1‐(4‐hydroxyphenyl)‐2,3,4,5‐tetrahydro‐1H‐3‐benzazepine) has been synthesized in both racemic mono and enantiomerically pure ditritiated form; SKF 38393 (7,8‐dihydroxy‐1‐phenyl‐2,3,4,5‐tetrahydro‐1H‐3‐benzazepine) has also been labeled with tritium. In each case labeling was accomplished via tritiation of the appropriate ring halogenated precursor with tritium gas ove

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240204

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

Abstract4‐[2‐(Di‐n‐propylamino)ethyl]‐2(3H)‐indolone (1) labeled with14C at C2 was prepared by a simple and efficient procedure involving carbonation of a stabilized benzyllithium species, followed by ring closure under hydrolytic

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240205

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe synthesis and purification of3H‐nitroglycerin (glyceryl trinitrate, GTN) from commercially available3H‐glycerol of high specific activity are described. The optimum microscale reaction conditions were defined. Purification of the product by thin‐layer chromatography produced3H‐GTN with an overall molar yield of 65% and a radiochemical purity o

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240206

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe synthesis of tritiated male‐activating steroids of the aquatic fungusAchlya, 7‐deoxy‐7‐dihydroantheridiol (7‐DA) and antheridiol, has been achieved by aldol condensation of 3β‐acetoxy‐23,24‐dinorchola‐1,5‐dien‐22‐al and the carbanion of 3‐isopropyl‐2‐butenolide. The product with the desired stereochemistry (22S,23R) was isolated and reduced with3H2in the presence of tris(triphenylphosphine)rhodium chloride. Acid hydrolysis of the acetate gave 1,2[3H]‐7DAwhich had a specific activity of 40 Ci/mmol. 1,2[3H]‐7DAwas converted to 1,2[3H]‐antheridiol by protecting the hydroxyl groups as the disilyl ethers, oxidation to the 7‐ketone with chromium trioxide‐dimethylpyrazole and removal of the protecting groups by gentle acid treatment. 1,2[3H]‐7DAhas been used to detect

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240207

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractMethods are described for the synthesis of 4‐chloro(1prime;,2prime;,3prime;,4prime;,5prime;,6′‐13C6)biphenyl; 3,3′,4,4′‐tetrachloro(13C12)biphenyl; and 2,2′,3,3′,5,5′,6,6′‐octachloro(13C12)biphenyl; decachloro(13C12)biphenyl from (13C6)benzene of ≧ 99 atom % isotopic purity, on scales of 100 mg to 1 g. The gas chromatographic retention time of each13C‐polychlorinated biphenyl (PCB) matched that of the corresponding unlabeled commercial reference standard, and the mass spectrum of each compound was consistent with an isotopic purity of ≧ 99 atom %13C. These compounds are useful as recovery surrogates and internal standards in the determination of PCBs in a

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240208

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractNucleophilic substitution of benzyl‐type chlorides with cyanide ion in deuterochloroform, deuteroacetonitrile or deuterobenzene catalyzed by 18‐crown‐6 results in the introduction of deuterium onto the benzyl carbon. Benzyl cyanides are labelled by refluxing with cyanide ion and crown ether in deutero solvent. Two such exchanges in deuterochloroform produced greater than 90% incorporation. Side‐chain labelled phenyl‐ethylamine, tryptamine andm‐ andp‐tyramine were synthesize

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240209

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractMethods for the enzymic synthesis, isolation, purification and analysis of the14C labelled intermediates that are characteristic of the L‐type pentose phosphate pathway are described. These are D‐glyceroD‐idooctulose 1, 8‐bisphosphate and 8‐monophosphate; D‐glyceroD‐altrooctulose mono‐ and bisphosphates; sedoheptulose 1,7‐bisphosphate and D‐arabinose 5‐phosphate. The procedures for the preparation of octulose‐ and sedoheptulose bisphosphates are based on the aldolase‐catalyzed condensation of dihydroxyacetone phosphate with appropriately14C‐labelled aldo pentose 5‐phosphates and erythrose 4‐phosphate respectively. D‐GlyceroD‐idooctulose 8‐phosphate and itsaltroepimer were prepared in transketolase catalyzed reactions involving β‐hydroxypyruvate and appropriately14C‐labelled aldohexose 6‐phosphates. [U‐14C] D‐arabinose 5‐phosphate was synthesized by reacting [U‐14C] glucosamine 6‐phosphate with ninhydrin. The authenticity of each of the14C‐labelled sugar phosphates was confirmed using a variety of chromatographic methods, enzymatic analytic methods and NMR spectroscopy.The14C labelled compounds are used in investigations involving the search for the identity of the pentose pathway in tissuesinvitro, for the measurement of L‐type pathway enzyme reactions and for testing

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240210

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe accuracy of the quantification of the tritium distribution in labelled compounds may be reduced by differential nuclear Overhauser effects, especially for compounds in which the different tritiated positions differ in the number of protons surrounding them.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580240211

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY