bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis of 14C‐labeled N‐carbonylbenzyloxyphenylalanine methylorthoester
Authors: Partington Curtis R. , Mertes Mathias P. 
Published: October 2006

AbstractPhenylpropionitrile‐1‐14C was prepared by the reaction of potassium cyanide‐14C with phenethyl chloride. Conversion of the nitrile to methylphenyl‐propioimidate‐1‐14C hydrochloride, chlorination with Cl2 in NaOCl to produce methyl N‐chlorophenylpropioimidate‐1‐14 C, followed by treatment with sodium methoxide produced phenylalanine methylorthoester‐1‐14C. Treatment of the amine with n‐butyllithium followed by addition of benzylchloroformate produced N‐carbonylbenzyloxy‐phenylalanine methylorthoester‐1‐14C.
Syntheses with stable isotopes: Benzidine‐15N2
Authors: Whaley Thomas W. 
Published: October 2006

AbstractBenzidine‐15N2 was prepared from 4,4′‐biphenyldicarboxamide‐15N2 by the Hofmann amide degradation. The diamide, in turn, was obtained from 4,4′‐biphenyldicarbonyl chloride and ammonium‐15N sulfate. An overall yield of 30–35% was obtained for the two steps. An attempted synthesis of N‐hydroxybenzidine is also described.
High specific activity labelling of some tricyclic antidepressants
Authors: Buchman O. , Pri‐Bar I. 
Published: October 2006

AbstractActivated palladium is used as catalyst for the hydrogen‐tritium exchange in tricyclic antidepressants. The specific activities obtained are: desipramine: 44.9 Ci/mmol; imipramine: 14.9 Ci/mmol; notriptyline: 2.0 Ci/mmol and amitriptyline: 1.7 Ci/mmol.
Effect of reaction temperature on enzyme conversion of pyrimidine bases to nucleosides and 2′‐ deoxynucleosides
Authors: Filip J. , Přitasil L. , Nejedlý Z. , Veselý J. , Čihák A. 
Published: October 2006

AbstractConversions of uracil to uridine and of uracil and thymine to the corresponding 2′‐deoxyribonucleosides catalyzed by the cell‐free extract of Escherichia coli B take place both at 37°C and 2°C. The yield of nucleosides formed during the short‐term incubation was higher at 37°C while during long‐term incubation it was higher at 2°C with the implication that the degradation of ribose‐ and 2′‐deoxyribose‐1‐phosphates in reaction mixtures kept at lower temperature is less considerable. The amount of 2′‐deoxyribonucleosides formed at 2°C was higher than that of ribonucleosides.
The synthesis of 14C‐labelled N‐aminooxyacetyl‐N′‐isonicotinoyl‐hydrazine dihydrobromide
Authors: Koltai E. , Bánfi D. , Kisfaludy L. , Dancsi L. 
Published: October 2006

AbstractThe N‐aminooxyacetyl‐N′‐isonicotinoylohydrazine dihydrobromide was labelled with 14C in two different positions. In one case we applied a new synthesis route via 14C labelled 4‐cyanopyridine and isonicotinic acid. In the other case aminooxyacetic acid was labelled in its carboxyle group.
A novel method for the preparation of highly tritiated methyl iodide, and its use for the syntheses of methyl‐3H‐labelled diazepam and the methiodides of (+)‐ and (−)‐bicuculline
Authors: Schwob R. , Wuersch J. 
Published: October 2006

AbstractThe syntheses of methyl‐3H‐labelled diazepam (4) and the methiodides of (+)‐ and (−)‐bicuculline (5) labelled with tritium in their methyl groups are described. Also reported here is a novel method for the preparation of triti‐ated methyl iodide (3) serving as the radioactive precursor for the substances mentioned above.
Synthesis of 14C‐labelled compounds of biological interest: 4‐methyl‐2‐pyridyl‐2‐furamide hydrochloride /MEPAF/
Authors: Ozdowska Zofia 
Published: October 2006

AbstractA method of carbon‐14C introduction into the molecule of a new drug 4‐methyl‐2‐pyridyl‐2‐furamide hydrochloride /MEPAF/ has been elaborated and furan‐2‐14C‐carboxylic acid has been synthesized. Radioactivity distribution and chemical yields in this synthesis were established.
The synthesis and chemistry of [11‐14C]‐dibenz[b,f] [1,4]oxazepine
Authors: Harrison J. M. , Inch T. D. , Upshall D. G. 
Published: October 2006

AbstractThe synthesis of [11‐14C]‐dibenz[b,f][1,4]oxazepine 1 is described. Chromium trioxide – pyridine oxidation of 1 gives [11‐14C]‐10, 11‐dihydrodibenz [b,f][1,4] oxazepin‐11‐one 3 which on hydrolysis gives 2‐amino‐2′‐[14C]‐carboxydiphenylether 4. Hydrogenation of 1 affords [11‐14C]‐10, 11‐dihydrodibenz[b,f][1,4]oxazepine 5. The enzymic conversion of 1 into 2‐amino‐2′‐[14C]‐hydroxymethyldiphenyl ether 6 is described.
Synthesis of 1,2‐benzenedicarboxaldehyde‐d6 through the ozonization of naphthalene‐d8
Authors: Kwant B. H. 
Published: October 2006

AbstractNaphthalene‐d was ozonized and the perdeuteroozonide was directly converted to 1,2‐benzenedicarboxaldehyde‐d by using dimethylsulfide. The perdeuteroozonide was also converted to 1,2‐benzenedicarboxaldehyde‐d6 through a three step synthesis, with the following intermediates: 2‐formylbenzoic acid‐d6, 2‐formylbenzoic acid‐d5 methylester and 1,2‐bis(hydroxymethyl‐d2) benzene‐d4. Both synthetic methods were described in detail.
A novel synthesis of maleic anhydride‐1‐ and ‐2‐13C and its subsequent conversion to labeled maleic hydrazide
Authors: Patterson John M. , Braun Loren L. , Haidar Nabeel F. , Huang Jack C. , Smith Walter T. 
Published: October 2006

AbstractMaleic anhydride‐1‐ and 2‐13C were synthesized respectively from the available aspartic acid‐4‐ and ‐3‐13C by way of the corresponding bromosuccinic acids and their anhydrides. The maleic anhydrides were converted into 1,2‐dihydro‐3,6‐pyrida‐zinedione‐3‐ and ‐4‐13C on treatment with aqueous hydrazine sulfate. Nitrogen‐15 labeled 1,2‐dihydro‐3,6‐pyridazinedione was obtained from the latter reaction using hydrazine‐15N sulfate.
Synthesis of β‐alanyl‐arginyl‐glycyl‐phenylalanyl‐phenyl‐alanyl‐typosine amide labelled with tritium or carbon‐14
Authors: Hayashi Nobuyoshi , Kawakami Takeo , Shinozaki Kazuo , Wakimasu Mitsuhiro , Fujino Masahiko 
Published: October 2006

AbstractThe synthesis of β‐Ala‐Arg‐Gly‐Phe‐Phe‐Tyr‐NH2 labelled with tritium on the tyrosine residue or with carbon‐14 on the arginine residue is described. The tritium labelled compound VII was prepared in 49% radiochemical yield from L‐[3, 5‐3H] tyrosine and benzyloxycarbonyl‐β‐alanyl‐nitro‐arginyl‐glycyl‐phenylalanyl‐phenylalanine. The carbon‐14 labelled compound XVI was synthesized in 17% radiochemical yield from L‐[U‐14C]arginine and glycyl‐phenylalanyl‐phenylalanyl‐tyrosine amide.
Stereospecific synthesis of Δ24‐sterols labelled on the 26‐ or 27‐methyl group
Authors: Nicotra F. , Ronchetti F. , Russo G. 
Published: October 2006

AbstractA convenient synthesis of Δ24‐sterols labelled on the 26‐ or 27‐methyl group, exemplified by the synthesis of [26‐3H]‐lanosterol, is described. Oxidation of lanosteryl acetate with SeO2 gives 3β‐acetoxylanosta‐8, 24‐dien‐26‐al; this is reduced to the corresponding labelled alcohol with KB3H4 and the obtained hydroxymethyl group is reduced to methyl group by hydrogenolysis of its sulfate monoester. 26‐Hydroxylanosterol can be transformed into 27‐hydroxy lanosterol by E→Z olefin inversion, so allowing the synthesis of lanosterol stereospecifically labelled at C‐27. Desmosteryl acetate analogously affords the corresponding 26‐aldehyde, which is easily reduced to the 26‐alcohol.3H‐stereospecific synthesis.
Synthesis of d,l‐1‐13C‐methionine
Authors: Andresen B. D. 
Published: October 2006

AbstractThe stable, isotopically labelled amino acid d, 1‐113C‐methionine, was prepared synthetically from 90% K13CN and 3‐(methylthio‐propionaldehyde. Chromatographic, infrared and mass spectrometric properties are presented which aid in the identification of this compound in body fluids and tissues.
Chemical synthesis of labelled intermediates in cyanogenic glucoside biosynthesis
Authors: Møller Birger Lindberg 
Published: October 2006

AbstractChemical syntheses of [UL‐ 14C]‐labelled N‐hydroxytyrosine, p‐hydroxyphenylpyruvic acid oxime, p‐hydroxyphenylacetaldoxime, and p‐hydroxyphenylacetonitrile in high yields from L‐[UL‐14 C]‐tyrosine are described. These syntheses involve initial conversion of L‐tyrosine to p‐hydroxyphenylpyruvic acid, which then is allowed to react with hydroxylamine to form p‐hydroxypheny lpyruvic acid oxime. N‐Hydroxytyrosine is obtained from the latter by reduction with sodium cyanoborohydride, and is oxidatively decar‐boxylated to p‐hydroxyphenylacetaldoxime by treatment with ammonia. Finally, p‐hydroxyphenylacetonitrile is obtained by dehydration of the aldoxime with thionylchloride. All synthesized compounds were identified by combined GLC/MS of their trimethylsilyl derivatives. The commercial availability of several specifically labelled 14C, 2H, and 3H tyrosines and of 2H and 3H sodium cyanoborohydride makes the method equally useful for synthesis of various specifically labelled compounds.
Synthesis of deuterium‐labeled nitrosomethylethylamines
Authors: Mangino Mario M. , Lijinsky William , Singer George M. 
Published: October 2006

AbstractEthyl isocyanate, N‐methylacetamide, N‐methylacetamide‐d3, and N‐methylacetamide‐d6 were reduced with lithium aluminum deuteride and then nitrosated with sodium nitrite to yield, respectively, nitrosomethyl (‐d3) ethylamine, nitrosomethylethyl (α‐d2) amine, nitrosomethylethyl (‐d5) amine, and nitrosomethyl (‐d3) ethyl (d5) amine. The characterization of the compounds by mass spectrometry is described.
Fluorine‐18 labelling of ortho‐fluorohippuric acid by isotope exchange reaction
Authors: Ndiokwere Ch. L. 
Published: October 2006

AbstractThe 18F‐labelling of o‐fluorohippuric acid by isotope exchange reactions has been studied in several organic solvents under varying reaction conditions. The solvent mixture ethanol/water (1:1) was found suitable for the isotope exchange reaction: a 100 per cent isotope exchange was observed for this system after an exchange time of one and half hours. No isotope exchange was observed in the molten state of the exchanging species.
Preparation of 35S‐labelled l‐methionine and l‐cystine by biosynthesis
Authors: Albahari S. R. , Skakun‐Todorovi M. B. 
Published: October 2006

AbstractThe modified method for biosynthesis of L‐methionine‐35S and L‐cystine‐35S from baker's yeast (Saccharomyces cerevisiae) is described. The yeast was cultivated in a sulphur‐deplated medium containing carrier‐free Na235SO4, under air bubbling during 24 hours. Yeast proteins were hydrolyzed enzymatically into free amino acids, and L‐methionine‐35S and L‐cystine‐35S were isolated by ion‐exchange chromatography on a column. Radioactive yields for L‐methionine‐35S and L‐cystine‐35S were 30% and 10%, respectively. The obtained products have high specific activity, 1–10 Ci/mmol, and radiochemical purity better than 95%.
Preparation of 2,4‐diamino‐6‐(diallylamino)‐s‐triazine‐2,4‐14c and its hypotensive metabolite, 2,4‐diamino‐6‐(diallylamino)‐s‐triazine‐2,4‐14c 3‐oxide
Authors: Thomas Richard C. 
Published: October 2006

Abstract2,4‐Diamino‐6‐(diallylamino)‐s‐triazine‐2,4‐14C was prepared from K14CN in a four step sequence of reactions. The product was obtained in 26% yield at a specific activity of 1.01 mCi per mM. This product was converted to the hypotensive agent, 2,4‐diamino‐6‐(diallylamino)‐s‐triazine‐2,4‐14C 3‐oxide in 37% yield by oxidation with m‐chloroperbenzoic acid.
Preparation of carbon‐14 labeled 2‐phenyl‐3‐[p‐(2‐diethylaminoethoxy) phenyl]‐6‐methoxyindene hydrochloride
Authors: Thomas Richard C. , Marlatt Paul E. 
Published: October 2006

Abstract2‐Phenyl‐3‐[p‐(2‐diethylaminoethoxy)phenyl]‐6‐methoxyindene‐314C hydrochloride was prepared from phenylacetic acid‐1‐14C in a four step sequence of reactions. The final product was obtained in 12.5% yield at a specific activity of 0.79 mCi per mM.
Markierung von N‐(2‐Diäthylaminoäthyl)‐S,S‐Diphenylsulfoximin mit Kohlenstoff‐14 in der Seitenkette und den Phenylringen
Authors: Liedtke B. , Vollmer K.‐O. 
Published: October 2006

AbstractAusgehend von Bariumcarbonat‐C wurde N‐(2‐Diäthylaminoäthy1)‐S,S‐diphenyl‐sulfoximin in 8 Stufen in Position 1 der Seitenkette radioaktiv markiert (IA). Bezogen auf die Ausgangssubstanz betrug die radiochemische Ausbeute 44,6%.Zur Markierung in den Phenylgruppen (IB) wurde Benzol‐ (U‐l4c) verwendet. Über Diphenylsulfoxid und das entsprechende Sulfoximin wurde IB mit einer Ausbeute von 30,4% erhalten.
Synthesis of deuterium‐labelled lithocholic acid
Authors: Baillie T. A. , Karls M. , Sjövall J. 
Published: October 2006

AbstractA convenient synthesis is reported of lithocholic acid labelled in high isotopic purity with two atoms of deuterium at C‐11. Incorporation of deuterium is achieved by base‐catalyzed equilibration of a 12‐oxo bile acid in heavy water. The product is converted in situ into its tosylhydrazone derivative which is reduced with sodium borohydride to afford the labelled 12‐deoxy bile acid.
The synthesis of specifically deuterated N‐acetyl‐6‐hydroxy‐5‐methoxytryptamine (6‐hydroxymelatonin) for use as an internal standard in mass spectrometry
Authors: Shaw G. J. 
Published: October 2006

AbstractSpecifically deuterated N‐acetyl‐6‐hydroxy‐5‐methoxytryptamine has been synthesised. The mass spectra of the labeled and unlabeled analogs are reported.
Synthesis of 14C‐labelled compounds. III. Synthesis of N‐Nitroso‐O,N‐14C‐dimethyl‐hydroxylamine
Authors: Arjungi Kusum N. , Krüger Friedrich‐Wilhelm , Wiessler Manfred 
Published: October 2006

AbstractC14‐labelled O,N‐dimethylhydroxyurethane is synthesized from C14‐labelled dimethylsulfate and N‐hydroxy‐urethane. It is further converted without purification into O,N‐14‐C‐dimethyl‐hydroxylammoniumchloride, which was then nitrosated with sodiumnitrite in acidic medium to give N‐Nitroso‐O,N‐14C‐dimethylhydroxylamine in 49% yield.
The syntheses of deuterium labelled tobacco alkaloids: Nicotine, nornicotine and cotinine
Authors: Nguyen Trong‐Lang , Castagnoli Neal 
Published: October 2006

AbstractA variety of deuterium labelled tobacco alkaloids has been prepared for metabolic studies. Reduction of myosmine with sodium borodeuteride provided nornicotine‐2′‐d1. Myosmine also underwent smooth base catalyzed exchange with deuterium oxide to myosmine‐3′,3′‐d2 which could be reduced to nornicotine‐3′,3′‐d2 and nornicotine‐2′,3′,3′‐d3. Thus avenues to nicotine alkaloids labelled at C2′, and/or C3′, have been established. Conversion of nornicotine to N‐ethoxycarbonyl‐nornicotine followed by lithium aluminum deuteride reduction gave nicotine‐N‐methyl‐d3. Nicotine‐2′,5′,5′‐d3 was prepared by oxidation of nicotine‐2′‐d1 to cotinine‐5‐d1 followed by lithium aluminium deuteride reduction.
Synthesis of iodine‐131 labelled 6β‐iodomethyl‐19‐norcholest‐5(10)‐en‐3α‐ol and 19‐iodocholest‐5‐en‐3α‐ol
Authors: Komatsu, H. , Maeda M. , Morita H. , Shimoirisa H. , Kojima M. 
Published: October 2006

Abstract6β‐Iodomethyl‐19‐norcholest‐5(10)‐en‐3α‐ol (VI) was synthesized by the homoallylic rearrangement of 19‐iodocholest‐5‐en‐3α‐ol (V), which was obtained by the hydrolysis of 19‐iodocholest‐5‐en‐3α‐ol acetate derived from the displacement of cholest‐5‐ene‐3α,19‐diol 3‐acetate 19‐toluene‐p‐sulfonate with sodium iodide in isopropanol.The radioiodinated V and VI were prepared by isotope exchange with sodium iodide‐I‐131 in acetone.
Synthesis of cholesteryl esters of labelled fatty acids
Authors: Grover A. K. , Cushley R. J. 
Published: October 2006

AbstractCholesteryl esters of variously labelled fatty acids have been synthesized in high yield by 1,1′‐carbonyldiimidazole activation of the acyl group and reaction of the resulting acylimidazole derivative with cholesterol. The method has been used to synthesize cholesteryl esters on micro and semimicro scales. Syntheses of the following esters are reported: cholesteryl palmitate‐1‐14C, cholesteryl palmitate‐d31, cholesteryl palmitate‐2,2‐d2, cholesteryl palmitate‐d31, cholesteryl palmitate‐2,2‐d2, cholesteryl palmitate‐3,3,4,4,5,5,6,6,7,7,8,8,9,9,‐10,10,11,11,12,12,13,13,14,14,15,15,16,16,16‐d29, cholesteryl 5‐doxylpalmitate and cholesteryl 16‐doxylstearate.
Syntheses with stable isotopes: Thymine‐2,6‐13C2
Authors: Redwine Carolyn M. , Whaley Thomas W. 
Published: October 2006

AbstractA three‐step synthesis of thymlne‐2,6‐13C2 from urea‐13C, sodium cyanide‐13C, and α‐bromopropionic acid is described. The last reaction involves hydrogenation of α‐cyano‐13C‐propionylurea‐13C in aqueous acetic acid and produces thymine‐2,6‐13C2 in 50–60% yield. The mechanism of this reaction is discussed.
Synthesis of [4‐14C]diosgenin
Authors: Ferdinandi E. S. 
Published: October 2006

Abstract[4‐14C]‐(25R)‐Spirost‐5‐en‐3β‐ol(diosgenin)l, specific activity 3.77 ± 0.02 mCi/mmole, was synthesized in four stees from (25R)‐5‐hydroxyspirost‐5‐en‐3‐oic‐3,5‐lactone 4 and [14C] methyl magnesium iodide with an overall yield of 18%. The preparation of the starting lactone from diosgenin is also described.
Preparation of selectively deuterated salen ligands
Authors: Brown Dennis G. , Srivanavit Chit 
Published: October 2006

AbstractA number of selectively deuterated derivatives of the common ligand N,N′‐ethylenebis(salicylidenimine), salen, have been prepared. The synthesis involves preparation of selectively deuterated salicylaldehydes. Procedures necessary to carry out these syntheses are described below.
Synthesis of 21‐diazoprogesterone‐6,7‐3H2
Authors: Chiu Wen‐Hsiung , Wolff Manfred E. 
Published: October 2006

AbstractThe preparation of 21‐diazoprogesterone‐6,7‐3H2 is described. Progesterone was dehydrogenated with chloranil to give Δ6‐dehydroprogesterone. Degradation of the pregnane side‐chain with sodium hypobromite gave the corresponding carboxylic acid. Catalytic reduction with carrier‐free tritium followed by treatment with oxalyl chloride and then diazomethane afforded 21‐diazoprOgesterone‐6,7‐3H2 with a specific activity of 42 Ci/mmol.
Labelling of neuroleptic butyrophenones. II. Synthesis of 2′amino‐4′‐fluoro‐4‐[4‐hydroxy‐4‐(3‐trifluoromethylpfenyl)piperidino]butyrophenone‐(carbonyl‐14C)
Authors: Nakatsuka Iwao , Kawahara Kazuo , Kamada Takeshi , Yoshitake Akira 
Published: October 2006

Abstract2′Amino‐4′‐fluoro‐4‐[4‐hydroxy‐4‐(3‐trifluoromemethylphenyl)‐piperidino]butyrophenone (ID‐470B)(1), a novel neuroleptic agent, was labelled with carbon‐14 at the carbonyl position for use in metabolic studies. The synthesis was achieved according to the reaction scheme shown in Fig. 1. Cyclopropyl 2,4‐difluorophenyl ketone‐(carbonyl‐14C) (2a) was prepared from cyclopropane‐carboxylic‐14c acid by the Friedel‐Crafts reaction with m‐difluoro‐benzene. Ring‐opening of 2a with hydrogen chloride gave 4‐chloro‐2′,4′‐difluorobutyrophenone‐1‐14c (3a). After ketalization of 3a, the resulted ketal (4) was condensed with the piperidine (5) and subsequently hydrolyzed with hydrochloric acid to give 6. Benzylamination of 6. with benzylamine, followed by debenzylation by catalytic hydrogenolysis gave ID‐4708‐(carbonyl‐14C) (1). The overall radiochemical yield of 1 from barium carbonate‐14C was 13%.
Preparation of radiolabelled 3α‐hydroxy‐7‐keto‐5β‐cholanic acid and its glycine and taurine conjugates
Authors: Carlson Gerald L. , Fromm Hans 
Published: October 2006

Abstract3α‐Hydroxy‐7‐keto‐5β‐cholanic acid has been prepared from cholic acid by a route which allowed introduction of 3H into positions 11 and 12 of the steroid C ring. Labelling with 14C was done by halodecarboxylation and resynthesis of the carboxyl function with 14C cyanide. The conjugates of both 3H‐ and 14C‐labelled compounds with glycine and taurine were prepared. 14C‐labelled compounds were prepared by degradation of the carboxyl‐containing side chain to the norchloride, which was used to prepare the homologous 14C‐containing nitrile. Hydrolysis afforded the acid in good yield. 3H was introduced into the C ring of the steroid nucleus by dehydration of 3α,12α‐dihydroxy‐7‐keto‐5β‐cholanic acid to the Δ11‐alkene which was catalytically tritiated. Physical and spectral data are presented to characterize the new compounds and TLC methods for purification are reported.
High yield sulfonation of [14COOH]‐litholcholic and [14COOH]‐taurolithocholic acids
Authors: Kelsey Morris I. , Molina Jorge E. 
Published: October 2006

AbstractSulfate esters of [14COOH]‐lithocholic and taurolithocholic acids have been prepared using a sulfur trioxide·pyridine complex as the sulfonating reagent. The utilization of liquid‐liquid extraction or reversed‐phase silica gel and Amberlite XAD‐2 chromatographic techniques gave pure sulfate esters which did not contain inorganic salt impurities. These methods offer a useful one‐step approach to the synthesis of sulfate esters at the milligram level using commercially‐available labeled precursors.
Synthesis of mevalonolactone‐2,3‐13C2
Authors: Degraw Joseph I. , Uemura Ieaki 
Published: October 2006

AbstractThe synthesis of mevalonolactone with 13C‐labels at positions 2 and 3 is reported. Hydrolysis of methyl 3‐hydroxy‐3‐methyl‐5,5‐dimethoxy‐valerate‐2,3‐13C2 to the aldehydo acid followed by reduction with sodium borohydride yielded the title compound. The material is useful as a substrate in biosynthetic studies using 13C‐NMR as an analytical tool.
Synthesis of ring 14C‐methyl labeled retinyl acetate
Authors: Colwell William T. , Soohoo Caroline , Degraw Joseph I. 
Published: October 2006

AbstractA method for incorporation of a 14C‐label in the ring geminal methyl moiety of Vitamin A is described. The procedure involves mono methylation of 2,6‐dimethylcyclohexanone with 14C‐methyl iodide as catalyzed by potassium hydride to afford 2‐14C, 2,6‐trimethylcyclohexanone. Subsequent condensation with an 11‐carbon acetylenic side chain, followed by reduction, acetylation and dehydration yielded 14C‐retinyl acetate. Final purification was achieved by preparative thin layer chromatography.
Synthesis of biopterin‐8a‐13C
Authors: Degraw Joseph I. , Brown Vernon H. , Uemura Ieaki 
Published: October 2006

AbstractThe synthesis of biopterin labeled at the angular 8a position with 13C is described. Cyano‐13C‐acetic acid was converted in three steps to benzyl 2‐aminocyanoacetate. Condensation of the amino cyano ester with the monoxime of 5‐deoxyl‐L‐arabinosone by a modification of the literature method afforded 2‐amino‐3‐benzyloxycarbonyl‐5‐(L‐erythro‐1′, 2′‐dihydroxypropyl) pyrazine‐1‐oxide‐2‐13C. This intermediate was condensed with guanidine to give biopterin‐8‐oxide‐8a‐13C, which was reduced to afford biopterin‐8a‐13C.
Preparation of 3H‐labelled apomorphine, N‐n‐propylnorapomorphine, and O, O‐dipivaloylapomorphine
Authors: Soine William H. , Salgo Peter , Smith Robert V. 
Published: October 2006

AbstractApomorphine and N‐n‐propylnorapomorphine were tritiated using trifluoroacetic acid‐ tritiated water mixtures. This provides a route to the synthesis of tritiated O,O‐dipivaloylapomorphine. Deuterium exchange and NMR studies indicate that exchange only involves protons at the C‐8 and C‐9 positions.
Synthesis of high specific activity R‐and S‐ warfarin‐3H
Authors: Cook C. E. , Tallent C. Ray , Ballentine Noel H. , Taylor George F. , Kepler John A. 
Published: October 2006

Abstract4‐Hydroxy‐3‐[3‐oxo‐1‐(3‐bromophenyl)butyl]‐2H‐1‐benzopyran‐2‐one (3′ ‐bromowarfarin) was synthesized and resolved into its enantiomers by formation of the d‐10‐camphorsulfonate diastereoisomers, which were separated by liquid chromatography and hydrolyzed. The pure enantiomers were reduced with tritium gas to yield R‐ and S‐4‐hydroxy‐3‐[3‐oxo‐1‐(phenyl‐3‐3H)butyl]‐2H‐l‐ benzopyran‐2‐one (R‐ and S‐warfarin‐3′‐3H) of specific activity 31.2 and 24.9 Ci/mmole, respectively. The compounds have been used to develop a stereoselective radioimmunoassay for warfarin enantiomers.
Tritiuh‐labelling in two phenylalanine residues of norleucine11‐substance P
Authors: Bienert M. , Klauschenz E. , Ehrlich A. , Katzwinkel S. , Niedrich H. , Tót G. , Teplán I. 
Published: October 2006

AbstractNorleucine11‐substance P and 4‐chlorophenylalanine 7.8‐Norleucine11‐ substance P were synthesized by fragment condensation. Phe/3H/7.8‐norleu‐cine11 ‐substance P was obtained by catalytic tritiation of the precursor peptide with a specific radioactivity of 27 Ci/mmole and full biological activity.