bluuebunny/crossref_metadata_2025_split huggingface dataset:
The preparation of tobacco constituents incorporating stable isotopes, I. The synthesis of d,l‐nornicotine‐1′‐15N and d,l‐nicotine‐1′‐15N
Authors: Edwards William B. , Glenn David F. , Green Frank , Newman R. H. 
Published: October 2006

AbstractIsotopically enriched d,l‐nornicotine‐11‐15N (24 atom % enrichment) was prepared in a single step from cyclopropyl 3‐pyridyl ketone and formamide‐15N (24 atom % enrichment). Methylation to d,l‐nicotine‐11‐15N (24 atom % enrichment) was accomplished using the Clark‐Eschweiler method.
Synthesis of carbon‐14 labelled C19‐steroids
Authors: Milewich Leon , Schweikert Hans U. 
Published: October 2006

AbstractThe carbon‐14 labelled steroids, androsterone‐4‐14C, isoandrosterone‐4‐14C, 5α‐androstanedione‐4‐14C, 5α‐androstane‐3β, 17β‐diol‐4‐14C, and 5α‐androstane‐3α, 17β‐diol‐4‐14C were synthesized from dihydrotestosterone‐4‐14C for use in studies of steroid metabolism.
The synthesis of 14C‐labeled suicide inactivators of monoamine oxidase
Authors: Fowler Joanna S. 
Published: October 2006

AbstractN‐[3‐(2,4‐dichlorophenoxy)propyl]‐N‐methyl‐2‐propynylamine‐1‐14C (14C‐clorgyline, 1a) and L‐N, α‐dimethyl‐N‐2‐propynyl‐1‐14C‐phenethylamine (14C‐L deprenyl, 1b) were synthesized by the Mannich reaction of 2‐methyl‐3‐butyn‐2‐ol, 14C‐formaldehyde, and secondary amines 3‐(2,4‐dichlorophenoxy)‐N‐methylpropylamine (2a) or L‐N, α‐dimethylphenethylamine (2b) followed by KOH catalyzed elimination of acetone from the respective Mannich base 3a or 3b.
The synthesis of deuterium labeled butylated hydroxytoluene (BHT)
Authors: Mercer J. R. , Wiebe L. I. 
Published: October 2006

AbstractAttempts were made to synthesize 3,5‐di‐t‐butyl‐4‐hydroxytoluene containing a deuterium label. 1. p‐cresol was alkylated with (D8)‐isobutylene. 2. 2,6‐di‐t‐butyl‐4‐hydroxytoluene was reacted with deuterated trifluoroacetic acid giving direct exchange. 3. 2,6‐dideutero‐4‐hydroxytoluene was synthesized and alkylated with isobutylene and with 2‐methyl‐2‐chloropropane and AlCl3. 4. BHT was treated with D2O and Pt2O in a catalytic exchange process. All methods gave labeled BHT but in all cases a mixture of isomers was found.
Preparation of pteroylglutamic acid‐3′,5′‐2H2 by acid catalyzed exchange with deuterium oxide
Authors: Hachey D. L. , Palladino L. , Blair J. A. , Rosenberg I. H. , Klein P. D. 
Published: October 2006

AbstractPteroylglutamic acid was labeled with deuterium by trifluoroacetic acid‐catalyzed exchange with deuterium oxide. The product, pteroylglutamic acid‐3′,5′‐2H2, was selectively labeled with deuterium in the 4‐aminobenzoyl portion of the molecule; there was no evidence for isotope incorporation at C7 or C9 of the pteridine ring or at the glutamate residue. Isotope composition of the pteroylglutamates was determined by chemical ionization mass spectrometry following a base‐catalyzed, oxidative cleavage to either 4‐aminobenzoic acid or 4‐aminobenzoylglutamic acid. Products from the exchange reaction typically contained 1% 2H0, 9% 2H1, and 90% 2H2 isotopic species.
Deuteration of catecholamines, catecholamine metabolites and tryptophan metabolites
Authors: Muskiet Frits A. J. , Jeuring Hans J. , Thomasson Cornelis G. , Van Der Meulen Jan , Wolthers Bert G. 
Published: October 2006

AbstractThe preparation of some deuterium labelled catecholamines, catecholamine metabolites and tryptophan metabolites is described. Simple exchange reactions in DC1/D20 solution or reductions with Li Al D4 were used. The deuterium labelled compounds prepared are suitable for use as internal standards for quantitative mass‐fragmentographic analysis of their unlabelled analogs in biological material. Mass spectra of trimethylsilyl and trimethylsilyl‐N‐trifluoroacetyl derivatives of 2,5,6‐trideutero vanillactic acid, 1,1‐dideutero‐1‐hydroxy‐2 (2,5,6‐trideutero catechol)‐ethane, 2,5,6‐trideutero epinephrine, 2,5,6‐trideutero normetanephrine and hexadeutero indole‐3‐acetic acid are given together with those of their natural occurring analogs.
Synthesis of /Tyr‐3H/4‐angiotensin II and /Phe‐3H/8‐angiotensin II via halogen‐derivatives of angiotensin II
Authors: Mezõ I. , Seproõi J. A. , Teplán I. , Morgat J. L. , Fromageot P. , Tóth G. , Sirokmán F. 
Published: October 2006

AbstractA method is described for the tritium labelling of angiotensin II in two different positions. /Tyr‐3H/4‐angiotensin II and /Phe‐3H/8‐angiotensin II of high specific radioactivity have been prepared starting from Dbt4‐angiotensin II and Cpa8‐angiotensin II, respectively.
The preparation of dimethyl(7‐2H3 2‐oxoheptyl) phosphonate
Authors: Taber Douglas F. , Lee Charles H. 
Published: October 2006

AbstractDimethyl (7‐2H3 2‐oxoheptyl) phosphonate 4 has been prepared from 2H3 methyl iodide. The phosphonate should be a useful reagent for the synthesis of deuterium labelled prostaglandins and thromboxanes.
An enzymatic procedure for the synthesis of 3H‐thymidine‐5′‐triphosphate
Authors: Preussel Brunhild , Fritz Marion , Lange Peter 
Published: October 2006

AbstractAn enzymatic method for synthesis of tritium‐labelled thymidine‐5′‐triphosphate is described. The procedure utilizes a nucleoside phosphotransferase from wheat germ and a partially purified thymidylate kinase from calf thymus. The product is isolated by ion‐exchange chromatography on DEAE‐cellulose and can be obtained in a yield of approximately 40% and at a radiochemical purity of 95%.
Preparation of 2,3‐dinitrilo‐1,4‐dithia‐9,10‐anthraquinone labelled with 14C or 35S or 14C+35S
Authors: Šeda J. , Fuad M. , Tykva R. 
Published: October 2006

AbstractA method was developed for the preparation of 2,3‐dinitrilo‐1,4‐dithia‐9, 10‐anthraquinone labelled with 14C or 35S or 14C+35S on a milligram scale with the use of the semiconducto‐graphic detection. The exchange of the 35S radionuclide in various stages of the preparation was examined in detail. By the present method, the following activities were obtained: 88 Ci of 14C/mol or 44 Ci of 35S/mol or 1.46 Ci of 14C + 75 Ci of 35S/mol.
Synthesis of [14‐14C] dexclamol hydrochloride and [14‐14C] butaclamol hydrochloride
Authors: Ferdinandi E. S. , Raman P. , Ross V. 
Published: October 2006

AbstractThe synthesis of two [14C] labelled compounds, dexclamol and butaclamol hydrochloride, having the octahydrobenzocyclohepta pyridoisoquinoline structure is described. Both compounds were prepared by the same synthetic route starting from silver [14C]‐cyanide and were labelled in the 14‐position. Butaclamol (specific activity 1.23 mCi/mmole) was obtained in 13% overall yield while dexclamol (specific activity 17.8 mCi/mmole), an optically active compound requiring resolution in its preparation, was obtained in 2% overall yield.
Synthesis of carbon‐14 and tritium labeled N,N′‐(2‐chloro‐5‐cyano‐1,3‐phenylene)dioxamic acid di‐tham salt
Authors: Hsi Richard S. P. , Johnson Tommy D. 
Published: October 2006

AbstractAcetylation of tritium and carbon‐14 labeled 4‐chloro‐3,5‐diaminobenzonitrile (Ia and Ib) with ethyl oxalyl chloride afforded diethyl N,N′‐(2‐chloro‐5‐cyano‐1,3‐phenylene)dioxamate (IIa and IIb). The diester II was hydrolyzed to give N,N′‐(2‐chloro‐5‐cyano‐1,3‐phenylene)dioxamic acid, which was isolated as the tris‐hydroxymethylaminomethane (THAM) salt III.
Synthesis of 14C‐labelled nitrosamines. IV synthesis of 14C‐methyl‐(1‐acetoxy) methyl nitrosamine and 1‐14C‐ethyl (acetoxy)ethyl nitrosamine
Authors: Braun Horst , Wiessler Manfred 
Published: October 2006

AbstractA scheme is developed for synthesizing 14C labelled α‐acetates of secondary α‐hydroxylated nitrosamines. In this manner 14C‐methyl (1‐acetoxy)ethyl nitrosamine and 1‐14C‐ethyl (1‐acetoxy)ethyl nitrosamine are synthesized in 16.3 and 33.3% yield, radiochemically pure.
Synthesis of propanolamine side chain deuterated propranolol, propranolol‐diol and 4‐hydroxypropranol
Authors: Walker Richard B. , Nelson Wendel L. 
Published: October 2006

AbstractSyntheses of 1‐(isopropylamino)‐3‐(1‐naphthyloxy)‐2‐propanol‐1,1,2,3,3‐d5 (1), 3‐(1‐naphthyloxy)‐1,2‐propanediol‐1,1,2,3,3‐d5 (2) and 1‐(isopropylamino)‐3‐(4‐hydroxy‐1‐naphthyloxy)‐2‐propanol‐1,1,2,3,3‐d5 (3) from epichlorohydrin‐d5 are described. Treatment of epichlorohydrin‐d5 with 1‐naphthol, in the presence of a catalytic amount of pyridine, afforded a mixture of 1‐chloro‐3‐(1‐naphthyloxy)‐2‐propanol‐1,1,2,3,3‐d5 (4) and 1,2‐epoxy‐(1‐naphthyloxy)‐propane‐1,1,2,3,3‐d5 which was converted to 4, with HCl or to 5 with 6N KOH. Reaction of 4 with isopropylamine afforded 1. Acid catalyzed hydrolysis of 5 afforded 2. A modification of the synthesis of 1 using 4‐methoxy‐1‐naphthol, epichlorohydrin‐d5 (1N NaOH) afforded epoxide 7, which was opened with isopropylamine. Ether cleavage with pyridine HCl completed synthesis of 1‐(isopropylamino)‐3‐(4‐hydroxy‐1‐naphthyloxy)‐2‐propanol‐1,1,2,3,3‐d5 (3).
The synthesis of deuterated methyl methacrylates
Authors: Ayrey G. , Wong D. J. D. 
Published: October 2006

AbstractMethyl esters of: 2‐methyl [3‐2H2]prop‐2‐enoic acid (methyl methacrylate‐d2, CD2C(CH3)CO2CH3) and 2‐[Me‐2H3]methylprop‐2‐enoic acid (methyl methacrylate‐d3, CH2C(CD3)CO2CH3) were prepared in high yield under mild conditions from carbomethoxymethyltriphenylphosphonium bromide in a new application of the Wittig reaction. The methyl ester of 2‐methylprop[2H5]‐2‐enoic acid (methyl methacrylate‐d5, CD2C(CD2CH3) was prepared from acetone‐d6 via the acetone cyanohydrin method. Densities of all three monomers are reported at 25, 45 and 60°C.
Syntheses de Glycerides Marques au Carbone 14
Authors: Danan J. L. , Pichat L. 
Published: October 2006

AbstractStarting from 1–2 isopropylidene sn–glycerol, the synthesis of mono and diglycerides labelled with 14C in the acyl moiety has been achieved.The acyl chloride method was found to be the best one for the esterification step.The various methods, hepe proposed with palmitic or lauric acid may be generalized for the obtention of other saturated glycerides.
An improved synthesis of 5‐fluoro‐2′‐deoxyuridine incorporating isotopic labels
Authors: Dawson W. H. , Dunlap R. B. 
Published: October 2006

AbstractThe title compound has been synthesized by a new route that requires less steps and gives higher overall yields than existing procedures. The synthesis makes use of low molecular weight starting materials that are commercially available in isotopically enriched forms and thereby enables the specific labelling of carbons in the pyrimidine ring. An improved synthesis of the versatile reagent methyl propiolate is also included.
Synthesis of [carboxyl ‐14C] 5 ‐ fluoroorotic acid
Authors: Silverman Richard B. , Kapili Leilani V. 
Published: October 2006

Abstract[Carboxyl ‐14C] 5 ‐ fluoroorotic acid was synthesized by the treatment of [carboxyl‐14C] orotic acid with trifluoromethyl hypofluorite followed by triethyl amine.
Markierung von Ethoxyquin mit Kohlenstoff‐14
Authors: Müller H. 
Published: October 2006

AbstractEthoxyquin (6‐Ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinoline) was labelled in position 2 and 4 by iodine‐catalyzed reaction of (2‐14C)‐acetone with p‐phenetidine. The radiochernical yield was 39,4%.
Synthesis of tritiated bromobenzene derivatives
Authors: Hanzlik Robert P. , Wiley Robert A. , Gillesse Timothy J. 
Published: October 2006

AbstractThe synthesis of 3H‐bromobenzene, 3H‐o‐bromotoluene, 3H‐o‐bromobenzonitrile, 3H‐o‐bromobenzotrifluoride is reported. The method involves exchange‐tritiation of the appropriate anilines in heptafluorobutyric acid, followed by diazotization and either reduction or Sandmeyer coupling of the diazonium salt.
Tritium labeling of steroids by microwave discharge activation of tritium gas
Authors: Chiu W. H. , Peng C. T. 
Published: October 2006

AbstractSteroids with diazo and azido functional groups were labeled with tritium atoms by microwave discharge activation of tritium gas. The specific activity of the products was increased by maximizing the exposure surface using glass fiber paper for dispersion, reducing the amount of sample to be exposed. and increasing tritium pressure. A 500 fold increase in specific activity was achieved in dispersed sample as compared to the solid. Addition of tritium atoms to 4,5 double bond in Δ4‐3‐keto steroid occurred, giving rise to a mixture of 5α‐ and 5β‐isomers in about equal quantities.
Marquage de la Pregnenolone au Carbjne 14 et au Deuterium en Position 21
Authors: Pussemier L. , Velde V Vande , Piraux M 
Published: October 2006

AbstractPregnenolone (Δ5 ‐pregnen‐3β‐ol‐20‐one) is labelled with 14C and deuterium in position 21. The radioactive carbon is inserted by the means of diazomethane‐14C. The deuteration is realized by the reduction of 21‐diazo‐pregnenolone under the action of iodhydric acid dissolved in D2O.
Synthesis of 5‐ethyl‐d5‐5‐phenyl‐2‐thioxobarbituric acid, primidone‐ethyl‐d5 and phenobarbital‐ethyl‐d5
Authors: Andresen Brian D. , Biemann K. 
Published: October 2006

AbstractThree deuterium labelled drugs, 5‐ethyl‐d5‐5‐phenylthiobarbi‐turic acid, primidone‐ethyl‐d5, and phenobarbital‐ethyl‐d5 have been prepared employinq a three step synthesis utilizing diethyl phenylmalonate and bromoethane‐d5. Overall isotopic purity of the labelled drugs was in excess of 95%. Complete synthetic techniques as well as spectral data of labelled intermediate and drugs are presented.
Application de la Propriete D'Isomerisation des Hydrocarbures Acetyleniques a la Synthe se D'Alcynes Deuteries
Authors: Janin A. , Lavalley J. C. , Saussey J. , Vallet Et A. 
Published: October 2006

AbstractWe have tried to apply isomerization‐exchange and isomerization methods to prepare acetylenes deuterated in well‐known chemical positions with high isotopic purity.We found that deuterated propyne was obtained by shaking propyne (allene) and NaOD in D2O at 150°C. After three exchanges, the isotopic purity of CD3CCD is close to 98,5 %. From 1‐pentyne, at 180°C, it appeared that CH3CH2CCCD3 is formed. Even after three exchanges, no deuterium was present in the methylene group.In the case of 2‐alkyne → l‐alkyne isomerization, we found that the method involving NH2Na gave impure deuterated commpounds. On the other hand, use of sodium as an isomerization agent gave isotopically pure 1‐alkynes. However the poor yield and the difficulties inherent in the use of sodium limited the utilization of this method.
Practically carrier‐free labelling of aromatic compounds with bromine‐77 via N‐chloro‐tetrafluorosuccinimide
Authors: Coenen H. H. , Machulla H.‐J. , Stöcklin G. 
Published: October 2006

AbstractA new method for practically carrier‐free aromatic bromination has been developed using N‐chloro‐tetrafluoro‐succinimide (NCTFS) and bromide‐77. The optimum bromination conditions have been determined using toluene as a model system. In trifluoroacetic anhydride (TFA), which proved to be the best solvent, a “one‐pot” synthesis with carrierfree bromide‐77 gives rise to a 52 % radiochemical yield of bromotoluenes. No benzylbromide is formed. At room temperature the reaction is completed within about 30 min, the highest yields being obtained at NCTFS‐concentrations of 2 · 10−2 mole/1. In pure anhydride (TFA) the chlorinating side‐reaction of NCTFS does not take place. The reactivity towards simple benzene derivatives (C6H5X, X = OCH3, CH3, H, F, Br, NO2) is strongly dependent on the activation of the aromatic ring. A high ortho‐ and particularly para‐selectivity is observed, and an electrophilic substitution process via ionic species is discussed.
Synthese De La N‐acetylmuramyl (OXO‐14C‐propyl)‐L‐alanyl‐D‐isoglutamine (MDP‐14C)
Authors: Pichat L. , Tostain J. , Lefrancier P. , Sina P. , Lederer E. 
Published: October 2006

AbstractSYNTHESIS OF N‐ACETYLMURAMYL (14C‐OXOPROPYL)‐L‐ALANYL‐D‐ ISOGLUTAMINE (14C ‐ MDP)Condensation of (1‐14C) DL‐2‐bromopropionic acid with benzyl 2‐acetamido‐4,6‐0‐benzylidene‐2‐deoxy‐β‐D‐glucopyranoside 7 in presence of sodium hydride gave 50 % of crystalline compound 3, having the correct stereochemistry of natural muramic acid. The latter, in presence of Woodward's reagent, reacted with L‐alanyl‐D‐isoglutamine benzyl ester hydrochloride, leading to compound 4. Removal of benzylidene and benzyl groups by successive acetic acid exposure and hydrogenolysis gave rise to 2‐acetamido‐2‐deoxy‐3‐0 (2‐D‐(14CO) propionyl‐L‐alanyl‐D‐isoglutamine)‐D‐glucopyranose (14C‐MDP) Specific activity : 42 mCi/mMole in a 10 % overall yield based on sodium (1‐14C) propionate.
Synthesis of nitrogen‐15 labelled uracil and its 1‐deuteromethyl 3‐deuteromethyl, and 1,3‐dideuteromethyl derivatives (1)
Authors: Lipnick Robert L. , Fissekis John D. 
Published: October 2006

AbstractA procedure is described for synthesizing uracil‐1,3‐15N2 in 77% yield by the condensation of urea‐15N2 with propiolic acid. The uracil‐1,3‐15N2 was employed subsequently in a random alkylation with dimethyl sulfate‐d6 to give 1‐methyl‐d3‐uracil‐1,3‐15N2, 3‐methyl‐d3‐uracil‐1,3‐15N2, and 1,3‐dimethyl‐d6‐uracil‐1,3‐15N2. Purification of the products resulting from both these reactions was achieved on an ion exchange column. The 15N and 1H NMR spectra obtained are consistent with these structures.
Synthesis of [ 2H ] and [13C15N] labelled analogues of the antiarrhythmic agent 4‐diisopropylamino‐2‐phenyl‐2‐(2‐pyridyl) butyramide phosphate (norpace®, G.D. searle & Co. Ltd.)
Authors: Dyer Robert L. , Harrow Terry A. , Honeyman Robert 
Published: October 2006

AbstractThe synthesls of [d14] and [13C 15N] analogues of the potent antiarrhythmic agent 4‐diisopropylamino‐2‐phenyl‐2‐(2‐pyridyl) butyramide phosphate is described.
14C‐labeled antimalarials. I. Synthesis of dl‐erythro‐ and threo‐α(2‐piperidyl)‐2,8‐bis(trifluoromethyl)‐4‐quinolinemethanol‐α‐14C
Authors: Yanko William H. , Deebel George F. 
Published: October 2006

AbstractErythro‐ and threo‐ isomers of α‐(2‐piperidyl)‐2,8‐bis‐(triflucoromethyl)‐4‐quinolinemethanol‐α‐14C hydrochloride and methanesulfonate were prepared from labeled carbon dioxide for metabolic and pharmacological studies. Intermediates were 2,8‐bis(trifluoromethyl) cinchoninic‐carboxy‐14C acid and 2,8‐bis(trifluoromethyl)‐4‐quinolyl 2‐pyridyl ketone‐14C. The ratio of erythro to threo isomers formed on hydrogenation of the precursor ketone was 5.6. The diastereomers were separated by recrystallization and preparative tlc. Erythro‐to‐threo conversion was effected by isomerization of the acetylated erythro isomers and deacetylation.
Biosynthesis of tritium, deuterium and carbon‐13 labeled cycloheximide
Authors: Hsi Richard S. P. , Witz Dennis F. , Stolle Wayne T. , Baczynskyj Lubomir , Scahill Terrence A. 
Published: October 2006

AbstractTritium, deuterium, and carbon‐13 labeled cycloheximide were prepared through fermentation of Streptomyces griseus in 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 labeled compounds.
Synthesis of nitrogen‐15 labeled 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX) and 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX)
Authors: Bulusu S. , Autera J. , Axenrod T. 
Published: October 2006

AbstractProcedures are described for the synthesis of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX) fully labeled with nitrogen‐15.
Enzymatic synthesis and chromatographic purification of L‐3‐[11C]‐lactic acid via D, L‐3‐[11C]‐alanine
Authors: Kloster G. , Laufer P. 
Published: October 2006

AbstractD,L‐3‐[11C]‐Alanine was prepared by methylation with 11CH3I of tert butyl 2‐isocyanoacetate and subsequent hydrolysis. Enzymatic reaction using glutamate pyruvate transaminase and lactate dehydrogenase in a coupled reaction yields L‐3‐[11C]‐lactic acid. The radiochemical yield is 45% for D,L‐alanine and 26.5% for L‐lactic acid at a specifie activity of 0.45 mCi/μmole. Synthesis time including purification by hplc is 23 min for D,L‐3‐[11c]‐alanine and 45 min for L‐3‐[11C]‐lactic acid, respectively.
13C labeled benzo[a]pyrenes and derivatives. 2. The synthesis of benzo[a]pyrene‐6‐13C
Authors: Simpson J. Ernest , Daub Guido H. , Vanderjagt David L. 
Published: October 2006

AbstractThe synthesis of benzo[a]pyrene‐6‐13C is described. Perinaphthane was converted to 6‐benzoyl‐carbonyl‐13C‐perinaphthane which was cyclized to 2,3‐dihydrobenzo[a]pyren‐6(1H)‐one‐6‐13C. Subsequent reduction of the ketone followed by dehydration and dehydrogenation gave benzo[a]pyrene‐6‐13C in 29% overall yield.
Synthesis of 14C and 35S labelled carbonyl sulfide
Authors: Chengelis Christopher P. , Neal Robert A. 
Published: October 2006

AbstractCarbonyl sulfide (COS) was prepared by a replacement reaction from potassium thiocyanate (KSCN) in 50% sulfuric acid. 14C‐COS or 35S‐COS can be prepared by the same method, depending on the position of the label in the starting KSCN. The yield of the final product is in excess of 60%, and radiochemical purity was 99.5%.
Synthese von [3‐14C]‐ und [Phenyl‐U‐14C] Olaquindox
Authors: Maul W. , Scherling D. , Seng F. 
Published: October 2006

AbstractOlaquindox is a new feed additive.[14C]Olaquindox, labelled in different positions, was needed for tracer‐studies of pharmacokinetics, biotransformation and residues in several species of animals.2‐ [N‐(2‐hydroxethyl)‐carbamoyl] −3‐methyl‐[3‐14C] quinoxaline‐1,4‐dioxide ([3‐14C]Olaquindox) was synthesized from barium[14C]carbonate (22 moles; 1.15 Ci) via[1‐14C]acetic acid, sodium[1‐14C] acetate, [1‐14C] acetylchloride, ethyl [3‐14C] acetoacetate and 2‐carbethoxy‐3‐methyl‐[3‐14C] quinoxaline‐1,4‐dioxide with an overall yield of 10%, based on barium[14C]carbonate. The radiochemical purity was better than 98% (tlc). The specific activities of three preparations were 10.5, 8.4 and 5.45 μCi/mg respectively.[phenyl‐U‐14C] Olaquindox was synthesized starting from [U‐14C] aniline (19.8 mmoles; 284.4 mCi). Intermediate products were N‐acetyl[U‐14C]aniline, 2‐nitro‐N‐acetyl[U‐14C] aniline, 2‐nitro[U‐14C] aniline and [U‐14C] benzofurazanoxide. The total yield was 50% as calculated for [U‐14C]aniline. At calibration samples of two preparations showed specific activities of 49.5 and 11.1 μCi/mg respectively. The radiochemical purity was checked by tlc and exceeded 98%.
Synthesis of (S)‐leucine‐13C3 and its metabolites
Authors: Yuan Sun‐Shine , Foos Joseph 
Published: October 2006

AbstractA synthesis for (S)‐2‐amino‐4‐methyl‐13C‐pentanoic‐2,5‐13C2 acid ((S)‐leucine‐13C3) is described. The alkyl chain was constructed by condensing acetone‐1,3‐13C2 with triethyl phosphonacetate‐1‐13C to form 3‐methyl‐13C‐2‐butenoic‐1,4‐13C2 acid (beta‐methylcrotonic‐13C3 acid) and this was reduced to 3‐methyl‐13C‐butanal‐1,4‐13C2 (isovaleryl aldehyde‐13C3). Conversion to (S)‐leucine‐13C3 was accomplished via the Strecker synthesis followed by enzymatic resolution.
Synthesis of 14C‐labelled 2‐(3‐benzoylphenoxy)‐2‐methyl propionic acid (LF.599)
Authors: Duc C. Luu , Charlon Cl. , Bourgogne J. P. , Sornay R. 
Published: October 2006

AbstractThe title product was labelled with 14C at the ketone group, from 3‐methoxybromobenzene in six steps. Complete synthetic techniques of the labelled drug are presented.
A one step synthesis of ring labelled melatonin‐3H with high specific activity
Authors: Liu Yu‐Ying , Minich Martha 
Published: October 2006

AbstractA mixture of brominated melatonin derivatives has been synthesized for use as starting material for preparation of ring tritium labelled melatonin by catalytic hydrogenolysis. The high specific activity obtained makes this product useful in radioimmunoassay studies.