bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 1‐[11C]‐D,L‐homocysteine thiolactone: A potential tracer for myocardial ischemia using PET
Authors: Hamacher Kurt , Hanuš Jan
Published: October 2006

The synthesis of 1‐[11C]‐D,L‐homocysteine thiolactone, a potential tracer for PET imaging of ischemic heart regions, is described. The labelling is achieved by reaction of [11C]carbon dioxide with α‐lithiated S‐(tetrahydropyran‐2‐yl)3‐thiopropylisonitrile. Deprotection of the mercapto group and lactonisation of the resulting thioamino acid is accomplished in an acid catalysed reaction. The radiochemical yield obtained is 10 to 15% and the synthesis time, including the HPLC purification is about 45 min.
Microbiological preparation of 3H‐labelled methane
Authors: Sandbeck Kenneth A. , Reeburgh William S.
Published: October 2006

Small quantities of tritiated methane were prepared by fermenting [methyl‐3H] methylamine hydrochloride using exponential phase, transiently starved, co‐cultures of methanogenic bacteria. This method gave the expected 75% yield of C3H4 from the substrate and produced H2‐free, low 3H2O background C3H4 for tracer studies.
Synthesis of all trans [3′‐14C]menaquinone‐4
Authors: Shimada K. , Tadano K. , Satoh T. , Hashimoto K. , Tanaka S. , Yuzuriha T.
Published: October 2006

A synthetic procedure for producing all trans [3′‐14C]menaquinone‐4 is described. The radiolabel is introduced using ethyl [3‐14C]acetoacetate as shown in the scheme. The final product has high chemical and radiochemical purity with a specific activity of 669 MBq/mmol. The overall radiochemical yield is 12%.
Carbon‐14 labelling of terbinafine, an antimycotic agent
Authors: Andres Hendrik
Published: October 2006

Terbinafine is a new antimycotic agent which is currently being tested worldwide in clinical trials.

The synthesis of [14C]Terbinafine, labelled in the naphthalene methane moiety as well as in the tertiary butyl group are described. The key step of the latter is the aluminium‐mediated tertiary butylation of an alkyne.
Mechanistic approach of the nucleophilic18F‐ exchange on 4′‐NO2‐spiperone using TBA18F or K2.2.2./K18F
Authors: Gysemans M. , Mertens J.
Published: October 2006

High yield single step preparation of 4′‐18F‐spiperone by 18F‐ for NO2 exchange in highly basic conditions fails when using 4′‐NO2‐spiperone as a precursor. This compound moreover inhibits radiofluorination of highly activated molecules in mentioned conditions. Inhibition is not provoced by ketalised analogues of the butyrophenone. This led to assume that enolisation of the butyrophenone was responsible for those phenomena. The assumption is supported by the fact that the results of inhibition experiments fit to a theoretical model.
The synthesis of [1′,3′‐3H]4‐(4′‐azido‐5′,6′,7′,8′‐tetrahydro‐5′,5′,8′,8′‐tetramethyl‐2′‐anthracenyl)benzoic acid as a probe of the retinoic acid receptor
Authors: Dawson Marcia I. , Hobbs Peter D. , Dorsky Albert , Morimoto Hiromi
Published: October 2006

The synthesis of [1′,3′‐3H]4‐(4′‐azido‐5′,6′,7′,8′‐tetrahydro‐5′,5′,8′,8′‐tetramethyl ‐2′‐anthracenyl)benzoic acid is described. This retinoid was designed as a photoaffinity probe of the receptor sites of cellular retinoic acid‐binding protein and the nuclear retinoic acid receptor protein. The [3H]azidoretinoid was prepared from 1,2,3,4‐tetrahydro‐1,1,4,4‐tetramethyl‐7‐(4‐methylphenyl)‐5‐nitroanthracene in five steps in 15% yield (89% radiochemical purity by HPLC). 1H and 3H NMR was used to confirm the sites of 3H substitution on the ring.
Synthesis of di‐t‐alkyl nitroxides enriched in 2H and 12C
Authors: Plachy W. Z. , Viereck J. C. , Yee C. W.
Published: October 2006

The synthesis of a family of di‐t‐alkyl nitroxides is described, beginning with N‐t‐butyl‐2‐methyl‐2‐nitrosopropane 2H18, 12C8 (12C‐pd‐DTBN) and including molecules with 9, 10, and 11 carbons. Eliminating the proton and, in some cases, the 13C isotopes simplifies the resulting electron spin resonance (ESR) spectrum and improves the spectral resolution. Solvent dependent ESR parameters are given for this family of monofunctional spin probes. ESR evidence is seen for rotational isomerization within the most sterically hindered probe molecules. Some of these spin probes are especially useful for ESR spin probe studies in biomembranes where a range of probe hydrophobicity is desired.
The synthesis and biodistribution of 3‐(4′‐[125I]‐iodophenyl)‐4‐aminobutyric acid, a radioiodinated analogue of baclofen
Authors: Wakita Y. , Kojima M. , Schwendner S. W. , McConnell D. , Counsell R. E.
Published: October 2006

Baclofen has been found to bind to receptors in the central nervous system that are specific for γ‐aminobutyric acid (GABA), a well known inhibitory neurotransmitter. This paper describes the synthesis of a radioiodinated analog of baclofen as part of an effort to develop receptor probes useful in single photon emission computed tomography. Preliminary biodistribution studies showed the radioiodinationed analog to be essentially stable to in vivo deiodination and have a distribution profile similar to that of baclofen.
Synthesis of carbon‐14 labeled leukotriene antagonist SK&F 104353
Authors: Shu Arthur Y. L. , Villani Anthony J. , Richard Heys J.
Published: October 2006

Enantiomerically pure (2S,3R)‐3‐[(2‐carboxyethyl)thio]‐3‐[2‐(8‐phenyloctyl)phenyl]‐2‐hydroxy[2‐14C]propionic acid ([14C]SK&F 104353) was synthesized from methyl chloro[2‐14C]acetate via a five step sequence. Darzens Condensation with 2‐(8‐phenyloctyl)benzaldehyde gave a trans epoxy ester which underwent epoxide opening with methyl 3‐mercaptopropionate to furnish a pair of regioisomers. The desired isomer was isolated by subjecting the mixture to retroaldol cleavage conditions to remove the unwanted component. Subsequent optical resolution as a derivative of (S)‐proline and hydrolysis of the 2S,3R diastereomer afforded the title compound with a 5% overall radiochemical yield.
An efficient synthesis of the crustacean hormone [12‐3H]‐methyl farnesoate and its photolabile analog [13‐3H]‐farnesyl diazomethyl ketone
Authors: Ujváry István , Prestwich Glenn D.
Published: October 2006

Tritium‐labelled methyl farnesoate ([3H]‐MF, 6.6 Ci/mmol) was prepared from a tritiated allylic alcohol derivative by an efficient new one‐pot halogen exchange‐reductive dehalogenation sequence. The resulting [3H]‐MF was converted in three steps to a diazomethyl ketone analog, [3H]‐FDK, which can be used for the photoaffinity labelling of MF binding proteins.
Syntheses of carbon‐13 and carbon‐14 labeled (methylenecyclopropyl)acetyl‐CoA
Authors: Baldwin John E. , Widdison Wayne C.
Published: October 2006

Methylenecyclopropyllithium reacts with 13C‐ or 14C‐oxirane to give labeled 2‐(methylenecyclopropyl)ethanol, which may be converted in three steps to the corresponding coenzyme A thioesters of (methylenecyclopropyl)acetic acid.
Synthesis and radioiodination of a meso‐tetra (hydroxynaphthyl) porphyrin and its sulphonated derivative as potential tumour localizers
Authors: Kaelin A C , Zanelli G D
Published: October 2006

The synthesis and radiolabelling with iodine‐125 of a sulphonated and non‐sulphonated meso‐tetra(hydroxynaphthyl) porphyrin is described. Complete demethylation of the meso‐tetra (methoxynaphthyl) porphyrin precursor to form the corresponding hydroxynaphthyl derivative could not be achieved using HBr. Sulphonation and radioiodination reactions were thus carried out on a mixture of hydroxy/methoxynaphthyl porphyrins. The weak mass spectrum exhibited by the sulphonated porphyrin derivative may reflect the highly polar nature of the compound. Neither of the iodinated porphyrins were found to localize in tumour tissue to any appreciable extent. Spleen uptake of the iodinated hydroxynaphthyl porphyrin was found to be much greater in tumour bearing mice than in normal (non‐tumour bearing) mice. This may be a result of porphyrin aggregation due to its limited water solubility.
One step conversion of glutarimide‐2,6‐14C to pentachloropyridine‐2,6‐14C and its subsequent use in the synthesis of 2‐octyl (4‐amino‐3,5‐dichloro‐6‐fluoro‐2‐pyridinyloxy‐2,6‐14C)acetate
Authors: McKendry L. H.
Published: October 2006

A convenient method of preparing 2‐octyl (4‐amino‐3,5‐dichloro‐6‐fluoro‐2‐pyridinyloxy‐2,6‐14C)acetate from glutarimide‐2,6‐14C is described. The process includes a novel one‐step conversion of glutarimide‐2,6‐14C to pentachloropyridine‐2,6‐14C.
Synthesis of 1‐ and 3‐11C‐labelled L‐lactic acid using multi‐enzyme catalysis
Authors: Bjurling Peter , Långström Bengt
Published: October 2006

The synthesis of 1‐ and 3‐11C‐labelled L‐lactic acid from the corresponding racemic 1‐ or 3‐11C‐labelled alanine using a multi‐enzymatic reaction route, is presented. DL‐[1‐11C]Alanine was synthesised by reacting sodium 1‐hydroxy‐ethyl sulfite with hydrogen [11C]cyanide, obtained from [11C]carbon dioxide, and ammonia followed by acid hydrolysis. DL‐[3‐11C]‐Alanine was synthesised by a methylation of a glycine derivative, N‐(diphenylmethylene)‐glycine tert‐butyl ester, with [11C]methyl iodide, obtained from [11C]carbon dioxide, and subsequent hydrolysis. The racemic 1‐ or 3‐11C‐labelled alanine was then converted to pyruvic acid, by D‐amino acid oxidase/catalase and glutamic‐pyruvic transaminase, which was directly reduced to L‐lactic acid by L‐lactic dehydrogenase in a one‐pot procedure. The total synthesis time was 40 minutes, counted from release of [11C]carbon dioxide. The decay corrected radiochemical yields were ca. 80% for L‐[1‐11C]lactic acid, based on hydrogen cyanide, and ca. 60% for L‐[3‐11C]lactic acid, based on carbon dioxide. The radiochemical purities were higher than 99% analysed by HPLC.
Synthesis of 13C‐enriched and 14C‐labelled dithiopyr
Authors: Mehrsheikh Mohammad E. , Clizbe Lane A. , Singh Harbhajan , Purdum Wr
Published: October 2006

This report describes the synthesis of the 13C‐enriched and 14C‐labelled title compound starting from isotopically labelled isovaleraldehyde.
Synthesis of tetramethylethylenedioxydi‐[14c]‐methylsilane
Authors: Vidal Alain , Joachim Francis , Papirer Eugène
Published: October 2006

The synthesis of tetramethylethylenedioxydi‐[14C]‐methylsilane, a molecule used as a plasticizer in polysiloxane/silica blends, is described. This compound was synthesized in a 48% overall radiochemical yield from [14C]‐methyl iodide and with a specific radioactivity of 33 μCi/mmole. It was used to study the competitivity of adsorption of plasticizers and models of polydimethylsiloxanes towards silicas.
Iron‐59 labelled sodium nitroprusside
Authors: Bates J. N.
Published: October 2006

Sodium nitroprusside, a potent vasodilator in man, is synthesized with the gamma‐emitting isotope 59Fe in a single‐step synthesis from potassium cyanide, sodium nitrite, and ferrous chloride. It is purified by anion exchange chromatography and assayed by ion‐pair high pressure liquid chromatography. 14C‐nitroprusside is prepared by the same methods.
Synthesis and radioiodination of ten aryl‐carbohydrate compounds for labeling monoclonal antibodies
Authors: Warren S. D. , Ali S. A. , Richter K. Y. , Krohn K. A.
Published: October 2006

Ten aryl‐carbohydrate ligands have been synthesized that potentially increase the tumor retention and decrease the deiodination of iodinated monoclonal antibodies used in the imaging and treatment of cancer. The compounds were synthesized via reductive amination reactions, purified with cation exchange chromatography, and characterized using 1H and 13C NMR. These compounds were then radioiodinated to assess their iodination characteristics, for subsequent experiments involving attachment to monoclonal antibodies.
Synthesis and optical resolution of the neurotoxin 2‐amino‐3‐([15N]‐methylamino)propanoic acid (BMAA)
Authors: Hu Yulin , Ziffer Herman
Published: October 2006

The synthesis of 2‐amino‐3‐([15N]‐methylamino)propanoic acid (synonyms, BMAA, β‐N‐methylamino‐alanine) from α‐acetamidoacrylic acid and [15N]‐methylamine is described. Enantioselective hydrolysis of the acetamide group, mediated by the enzyme Acylase 1 (EC 3.5.1.14), yielded (R)‐BMAA and the (S)‐α‐acetamido derivative. Acid hydrolysis of the latter compound yielded (S)‐BMAA.
Synthesis of N‐[N‐L‐γ‐glutamyl‐L‐cysteinyl‐(carbonyl‐14C)]‐glycine (glutathione‐14C) and of [Cys‐14CO]‐(5S,6R)‐LTC4
Authors: Parent P. , Leborgne F. , Lellouche J. P. , Beaucourt J. P. , Vanhove A.
Published: October 2006

[Cys‐14CO]‐glutathione or N‐[N‐L‐γ‐glutamyl‐L‐cysteinyl‐14CO] glycine was prepared by chemical synthesis, with the L,L‐natural configuration and a radiochemical yield of 1% based on sodium [14C] cyanide. This labelled compound was used to obtain [Cys‐14CO] with a yield of 15%. [Cys‐14CO]‐glutathione and [Cys‐14CO]LTC4 had a specific activity of 50 mCi/mmol (1.85 GBq/mmol).
Synthesis of the heteroarotinoid ethyl (E)‐4‐[2‐(3,4‐dihydro‐4,4‐dimethyl‐2H‐1‐benzopyran‐6‐YL)‐1‐ propenyl]benzoate‐9,10,11,20‐14C4
Authors: Sunthankar Prasanna , Darrell Berlin K. , Nelson Eldon C.
Published: October 2006

A synthesis of ethyl (E)‐4‐[2‐(3,4‐dihydro‐4,4‐dimethyl‐2H‐1‐benzopyran‐6‐yl)‐1‐propenyl]benzoate‐9,10,11,20‐14C4 (1) is described via a multistep procedure similar to that used to obtained the unlabelled compound 2. The latter has shown good activity in several assays compared to the standard trans‐retinoic acid (3). Treatment of methyl 3‐phenoxypropionate (4) with methylmagnesium iodide (obtained from H314C‐I) yielded the labelled tertiary alcohol 5. Cyclization of the alcohol 5 occurred in the presence of AlCl3 in nitromethane to give 4,4‐dimethylchroman (6). Acetylation of 6 with H3C14C(O)Cl produced ketone 7 labelled at three carbons. Reduction of the carbonyl group in 7 was effected with LiAlH4 and gave alcohol 8. Phosphorylation with triphenylphosphine hydrobromide in methanol led to the corresponding phosphonium salt 9. Addition of n‐butyllithium to 9 in ether at −78°C generated the expected Wittig reagent in situ, and to this was added labelled ethyl 4‐formylbenzoate [C2H5O214C‐C6H4‐CHO] (10). Workup, followed by chromatography of the oily product, afforded a solid. Recrystallization (abs. ethanol) gave 1 which was identical to 2 in terms of spectral data and melting point. The specific activity was determined to be 0.15 μCi/mg.
Synthesis of isotopically‐labelled ethylenethiourea
Authors: Doerge Daniel R. , Cooray Niranjala M. , Yee Austin B. K. , Niemczura Walter P.
Published: October 2006

13C‐, 14C‐ and 15N‐labelled ethylenethiourea was synthesized for NMR and radiotracer applications in metabolism and environmental fate studies. The products contained stable isotopes at 99% enrichment and the radiolabelled product had specific activity of 2.0 mCi/mmole.
Synthesis and characterization of 2‐hydroxymethyl‐1‐methyl‐4‐nitro‐5‐imidazolcarbonitrile‐4, 5‐14C
Authors: Ellsworth Robert L. , Meriwether Henry T. , Mertel Holly E.
Published: October 2006

Preparation of the title compound, a key intermediate required to assist in the investigation and development of a new class of substances for controlling coccidiosis, is described. This labeled substance was synthesized in 10 steps, with a 17% overall radiochemical yield, from oxalic‐1,2‐14C acid.
Synthesis of n‐butyl [3‐13C]acrylate
Authors: Šmejkal J. , Hanuš V. , Linhart I. , Elbert T.
Published: October 2006

A four step synthesis of n‐butyl [3‐13C]acrylate from [13C]methyl iodide is described. The procedure involves methylation of butyl acetoacetate, subsequent bromination, alkaline cleavage and, finally, dehydrobromination using cyclohexyldimethylamine. The overall yield was 5%.
The synthesis of 7‐chloro‐5‐pentadeuteriophenyl‐1‐methyl‐1h‐1,5‐benzodiazepine‐2,4(3H, 5H)dione ([2H5]clobazam)
Authors: Borel Anthony G. , Abbott Frank S.
Published: October 2006

Pentadeuteriophenyl clobazam 5 was synthesized in essentially quantitative isotopic purity, and characterized by 1H‐NMR and mass spectroscopy. The title compound was found to be ≥98% pure by HPLC, and its retention time (tR 6.17 min) was less than that of an authentic clobazam standard (tR 6.32 min). Of the five steps in the synthesis of 5, the most susceptible to deuterium exchange was the nucleophilic substitution of 2,4‐dichloronitrobenzene by aniline‐d7 to form N‐(5‐chloro‐2‐nitrophenyl)pentadeuteriophenylamine 2. In this step, the isotopic impurity aniline‐2,3,4,5,‐d5 introduced protons from nitrogen into the ortho and para positions of the deuteriophenyl ring of 2.
Synthesis of [3H] aminocyclopropane carboxylic acid (ACC) as a ligand for the glycine b receptor
Authors: Dappen Michael S. , Markos Charles S. , Gresk Christopher J. , Cordi Alex A.
Published: October 2006

The synthesis of [3H] Aminocyclopropane carboxylic acid (ACC, 1) at high specific activity and high purity is described. The compound has been developed as a specific ligand for the Glycine‐B binding site.
Preparation of deuteriated adipic [2H2]‐, [2H4]‐, [2H6]‐, and [2H8]‐acids by use of kolbe electrolysis as a key reaction
Authors: Tashiro Masashi , Tsuzuki Hirohisa , Goto Hideyuki , Ogasahara Shoji , Mataka Shuntaro
Published: October 2006

Using Kolbe electrolysis of methyl hydrogen [2H0]‐, [2H2]‐, and [2H4]‐succinates as a key reaction, adipic [2,2‐2H2]‐, [2,3‐2H2]‐, [2,2,3,3‐2H4]‐, [2,3,4,5‐2H4]‐, [2,3,5,5‐2H4]‐, [2,2,3,3,5,5‐2H6]‐, and [2,2,3,3,4,4,5,5‐2H8]‐acids were prepared in high deuterium contents.
Synthesis of antiarrhythmic [phenyl‐14C]4′‐[(4‐piperidyl)carbonyl]‐methanesulfonanilides
Authors: Oinuma Hitoshi , Miyake Kazutoshi , Yamanaka Motosuke , Shino Mitsumasa , Hamano Sachiyuki
Published: October 2006

Syntheses of [phenyl‐14C]4′‐[[1‐[2‐(6‐Methyl‐2‐pyridyl)ethyl]‐4‐piperidyl]carbonyl]methanesulfon‐anilide dihydrochloride dihydrate (1) (14C‐E‐4031) and its pyridylpropyl analogue (2), that are selective class III antiarrhythmic agents, are described. A modified Michael reaction of (6), a key intermediate amine prepared from [U14C]aniline hydrochloride, with 6‐methyl‐2‐vinylpyridine (7) and alkylation of (6) with 4‐(3‐chloropropyl) pyridine (8) respectively produced compounds, (1) and (2), in satisfactory yields.
[82Br]cisplatin derivative: A potential biological model for cisplatin
Authors: Tinker N. D. , Sharma H. L. , McAuliffe C. A.
Published: October 2006

The complex cis‐[Pt(NH3)282Br2] has been prepared as a possible model for cisplatin, cis‐[Pt(NH3)2Cl2]. The stability of cis‐[Pt(NH3)282Br2] was investigated in 0.9% saline solution and sterile water. In both cases the 82Br label was rapidly displaced in the first hour (t1/2 = 73 min and 96 min respectively). Thus, cis‐[Pt(NH3)282Br2]cannot be used for determining the fate of the labile ligands of cisplatin.
Herz‐affinität von radioaktiven ruthenocen‐derivaten des chinuclidin‐3‐ol
Authors: Wenzel M.
Published: October 2006

Durch Kondensation von Ferrocenaldehyd mit Chinuclidin‐3‐on wurde 2‐Ferrocenyliden‐chinuclidin‐3‐on hergestellt und anschließend die Ketogruppe reduziert. Durch Zentralatom‐Austausch erhielt man die analogen radioaktiven Ruthenocen‐Derivaten, von denen die Organverteilung bei Ratten bestimmt wurde. Als Nebenprodukt erhielt man Ruthenocen‐Derivate, bei denen jeder der beiden Cyclopentadien‐Ringe mit einem Chinuclidinolether‐Rest substituiert war. Diese Substanzen zeigen eine hohe Myocard‐Anreicherung. Der Quotient Herz/Blut von 60: 1 übertrifft die Quotienten, die mit 99Tc‐TBI erhalten werden.
Stereoselective semi‐hydrogenation and deuteration of a diacetylenic precursor of leukotriene B4 methyl ester
Authors: Pontikis Renée , Merrer Yves Le , Depezay Jean‐Claude , Pétillot Yves , Rousseau Bernard , Beaucourt Jean Pierre
Published: October 2006

[6,7,14,15‐2H4)‐Leukotriene B4 methyl ester was prepared by reduction with deuterium gas of a suitable precursor (deuterium incorporation ≥ 90%). Several catalytic semi‐hydrogenations were effected in order to determine the best conditions for the labeling step.
Reductive amination of [18F]fluorobenzaldehydes: Radiosyntheses of [2‐18F]‐ and [4‐18F]fluorodexetimides
Authors: Wilson Alan A. , Dannals Robert F. , Ravert Hayden T. , Wagner Henry N.
Published: October 2006

Two [18F]‐labelled analogues of dexetimide, a potent muscarinic cholinergic receptor ligand, have been synthesised in good yields and at high specific activities. Reductive amination of [2‐18F]‐ and [4‐18F]fluorobenzaldehyde with norbenzyldexetimide and sodium cyanoborohydride gave, in a one‐pot reaction, good (≈︁20%) yields of high specific activity [2‐18F]‐ and [4‐18F]fluorodexetimide respectively. The labelled benzaldehydes may be useful synthetic precursors for the radiosyntheses of other complex radiotracers for use with positron emission tomography.
Tritium labeled trans‐4‐n‐butyl‐2,3‐3H‐cyclohexanecarboxylic acid. Preparation of testosterone 17β‐trans‐4‐n‐butyl‐2,3‐3H‐cyclohexanecarboxylate and [4‐14C]‐testosterone 17β‐trans‐4‐n‐butylcyclohexane carboxylate
Authors: Acosta C. K. , Cessac J. W. , Rao Pemmaraju N. , Kim Hyun K.
Published: October 2006

The synthesis of trans‐4‐n‐butyl‐2,3‐3H‐cyclohexanecarboxylic acid is described. The title compound was synthesized by catalytic tritiation of 4‐n‐butylcyclohex‐2‐enecarboxylic acid, which was obtained from a “double” Birch reduction of 4‐n‐butylbenzoic acid. The trans‐acid was isolated from a mixture of cis/trans diastereomers by the selective formation of a thiourea inclusion complex. The title compound was used for the synthesis of the 17β‐ester of testosterone. In addition, [4‐14C]‐testosterone was esterfied using unlabelled trans acid. The three radiolabelled compounds will be used in metabolism studies.
Carbon‐14 labelling of FCE 24578, an immunomodulating agent
Authors: Angiuli Patrizia , Vicario Gian Piero
Published: October 2006

Two syntheses of radiocarbon labelled FCE 24578, namely 2‐cyano‐3‐(1,4‐dihydro‐1‐phenyl‐[1]‐benzothiopyrano[4,3‐c]pyrazol‐3‐yl)‐3‐oxo‐N‐phenylpropanamide, are reported. The former gave, employing [1‐14C]acetonitrile as labelled starting material and with an overall radiochemical yield of 39%, [cyano‐14C]FCE 24578, 97% radiochemically pure and with a specific radioactivity of 299 MBq/mmol.

The latter was carried out with [ring‐U‐14C]benzoic acid to give [phenyl‐U‐14C]FCE 24578, 96% radiochemically pure, with specific radioactivity of 400 MBq/mmol in an overall radiochemical yield of 40%.
Synthesis of cefepime‐d3 and cefepime‐d8
Authors: Kamachi Hajime , Okita Takaaki , Tsuno Takashi , Naito Takayuki
Published: October 2006

Synthesis of cefepime‐d3 (6a) and cefepime‐d8 (6b) is described. Diphenylmethyl 7‐benzylideneamino‐3‐chloromethyl‐3‐cephem‐4‐carboxylate (2) was treated with sodium iodide to afford the iodide 3, which was, without isolation, allowed to react with N‐methyl‐d3‐pyrrolidine to give the quarternary salt 4a. Deblocking of 4a with HCO2H and HCl gave 7‐amino‐3‐(N‐methyl‐d3‐pyrrolidinio)methyl‐3‐cephem‐4‐carboxylate hydrochloride (5a). Acylation of 5a with benzotriazol‐1‐yl (Z)‐2‐(2‐aminothiazol‐4‐yl)‐2‐methoxyiminoacetate followed by treatment with dil. H2SO4 afforded 6a sulfate. In the same way, 6b was synthesized using N‐methyl‐pyrrolidine‐d8.
Synthesis of [3H]CP‐93,129: A selective radioligand for the 5‐HT1B receptor
Authors: Macor John E , Ryan Kevin , Chalabi Phillip M. , Windels James C. , Roth Robert W.
Published: October 2006

The synthesis of [3H]‐CP‐93,129, a potent radioligand for the serotonin 5‐HT1B receptor, is described. 5‐Butoxypyrrolo[3,2‐b]pyridine (2) is converted in 3 steps to 5‐butoxy‐1‐phenylsulfonyl‐2‐tritiopyrrolo[3,2‐b]pyridine (3c) via lithiation of C2, iodination of that anion, and tritium reduction. (3c) is converted to the title compound in two more steps analogous to methodology used in the synthesis of CP‐93,129, a potent and selective 5‐HT1B agonist.
Synthesis of 4‐0‐(4,6‐di[14C]ethylidene‐α‐D‐glucopyranosyl)‐4′‐demethyl‐4‐epipodophyllotoxin
Authors: Haynes U. J. , Swigor J. E.
Published: October 2006

The synthesis of the title compound (5) is described. Protection of 4‐0‐(4, 6‐ethylidene‐α‐D‐glucopyranosyl)‐4′‐demethyl‐4‐epipodophyllotoxin (1) with benzylchloroformate in the presence of pyridine gave 4‐0‐(4, 6‐ethylidene‐α‐D‐glucopyranosyl)‐4′‐carbobenzyloxy‐4‐epipodophyllotoxin (2). Treatment of (2) with acetic acid‐water produced 4‐0‐(α‐D‐glucopyranosyl)‐4′‐carbobenzyloxy‐4‐epipodophyllotoxin (3). Reaction of [14C]acetaldehyde diethylacetal with (3) introduced the label in the 4′,6′‐ethylidene position (4). Hydrogenation using 30% palladium on carbon yielded the title compound (5) in an overall yield of 6%.
Synthesis of pentamidine labelled with tritium and carbon‐14
Authors: Hesk David , Jones John R. , Lockley William J. S. , Wilkinson David J.
Published: October 2006

Tritium labelled pentamidine has been prepared with a specific activity of 90 mCi mmol−1 using a one‐step exchange reaction between the unlabelled drug and tritiated water. The labelling utilised a homogeneous rhodium trichloride catalyst and yielded pentamidine regiospecifically labelled in the positions ortho to the amidine groups. Carbon‐14 labelled pentamidine was prepared via a seven‐step procedure in which the isotope was introduced via a nucleophilic substitution of 4‐bromo‐phenol with copper(I) [14C]cyanide.
Synthesis of 6‐quinoxalin‐2,3‐14C2‐amine and derivatives via ethanedial‐1,2‐14C2
Authors: Landvatter Scott W. , Richard Heys J.
Published: October 2006

High specific activity ethanedial‐1,2‐14C2 has been prepared in 74% radiochemical yield by oxidation of paraldehyde‐14C6 with selenious acid. The crude ethanedial‐14C2 was directly condensed with 1, 2, 4‐benzenetriamine dihydrochloride in aqueous sodium carbonate giving 6‐quinoxal in‐2,3‐14C2‐amine in 56% yield. The quinoxaline was brominated and then converted to its isothiocyanate by reaction with thiophosgene. The isothiocyanate was directly converted to 5‐bromo‐6‐(2‐imidazol in‐2‐ylamino) quinoxaline‐2,3‐14C2 by reaction with ethylenediamine in refluxing 1: 1 methanol toluene. The overall radiochemical yield was 11% from paraldehyde‐14C6.
Synthesis of fluorine‐18 labeled 1,1‐difluoro‐2,2‐dichloroethyl aryl ethers by 18F‐for‐19F exchange
Authors: Kilbourn Michael R. , Subramanian Raghu
Published: October 2006

Fluorine‐18 labeled 1,1‐difluoro‐2,2‐dichloroethyl aryl ethers have been prepared by a facile 18F‐for‐19F isotopic exchange reaction. The isotopic exchange proceeds in good to excellent yields (up to 85%), and is dependent on reaction time, temperature, and concentration of reactants (aryl ether or fluoride ion). Substitution even occurs at room temperature in DMSO, and at elevated temperature (100 to 155°C) in DMSO or acetonitrile containing up to 20% water. Specific activities of 0.5‐55 Ci/mol have been achieved, with the products obtained in pure radiochemical and chemical form.
Synthesis of tritiated clenbuterol
Authors: Pri‐Bar Ilan , Buchman Ouri
Published: October 2006

Tritiated clenbuterol was prepared starting from 4‐aminoacetophenone (I) which was selectively brominated to 4‐amino‐3,5‐dibromoacetopheno ne (II), then to 4‐amino‐α,3,5‐tribromoacetophenone (III) and reacted with tert.butylamine to 4‐amino‐3,5‐dibromo‐α‐tert.butylaminoacetoph‐none(IV). (IV) was dehalogenated and reduced with tritium gas to give 2‐(tert.butylamino)‐1‐(4‐amino‐[3,5‐3H]‐phenyl)‐[1‐3H]‐ethanol (V). This tritiated compound underwent selective aromatic chlorination to give the desired 2‐(tert.butylamino)‐1‐(4‐amino‐3,5‐dichlorophenyl)‐[1‐3H]‐ethanol, [ethanol‐1‐3H]clenbuterol, with specific activity of 13.4 Ci/mmol (496 GBq/mmol).
Synthesis and tritium labeling of the highly potent mast cell‐degranulating substance P analog H‐Arg‐Pro‐Lys‐Pro‐NH‐C12H25
Authors: Bienert M. , Oehlke J. , Mittag E. , Niedrich H.
Published: October 2006

Tritium labeling of the mast cell degranulating substance P analog H‐Arg‐Pro‐Lys(3,4‐3H‐Pro)‐NH‐C12H25 by catalytic saturation of the dehydroproline (Dhp

Abbreviations: Ac, acetyl; Dhp, L‐3,4‐dehydroproline; DMA, dimethyl‐acetamide; DMF, dimethylformamide; HOBt, 1‐hydroxybenzotriazole; MA, mixed anhydride coupling; NMM, N‐methylmorpholine; ONSu, N‐hydroxysuccinimide ester; TEA, triethylamine.

) double bond is described. Catalytic tritiation in water afforded the radioactive analog with a specific activity of 1.07 TBq/mmol. Tenfold enhancement of the catalyst‐to‐substrate ratio resulted in a reduced specific activity of 0.74 TBq/mmol.
Synthesis of tetrazole‐13C and 1,2,4‐triazole‐1,2‐15N2
Authors: Rowlett Roger S. , Klysa Thomas , Shiraki William W.
Published: October 2006

We report here the syntheses of tetrazole‐13C and 1,2,4‐triazole‐1,2‐15N2 by simple, one‐step procedures using common, commercially available, isotopically‐labeled starting materials. tetrazole‐ 13C is conveniently prepared from K13CN and NaN3 in 70% yield, almost twice the best reported yield for (unlabeled) tetrazole by similar synthetic methods. 1,2,4‐triazole‐1,2‐15N2 was synthesized in 35% yield from hydrazine‐15N2 sulfate and 1,3,5‐triazine. From 15N‐NMR we determined that 15N was specifically incorporated into the 1 and 2 positions of the triazole ring.
Synthesis of 14C‐labelled methylglyoxal and S‐D‐lactoylglutathione
Authors: Clelland James D. , Thornalley Paul J.
Published: October 2006

[2‐14C]Methylglyoxal and S‐D‐[2‐14C]lactoylglutathione were synthesised from [2‐14C]acetone. Acetone was oxidised to methylglyoxal by selenium dioxide and was purified by distillation (yield: 23% based on acetone). Methylglyoxal was converted to S‐D‐lactoylglutathione by reaction with reduced glutathione catalysed by glyoxalase I (EC 4.4.1.5). S‐D‐Lactoylglutathione was purified by anion exchange chromatography on Dowex 1 (yield: 82%, based on methylglyoxal).
Synthesis of 1‐nitro‐2‐(p‐hydroxyphenyl)[2‐3H1]ethane
Authors: Halkier Barbara Ann , Olsen Carl Erik , Marcussen Jan
Published: October 2006

A racemic mixture of (R)‐ and (S)‐1‐nitro‐2‐(p‐hydroxyphenyl)[2‐3H1]ethane was synthesized from 1‐nitro‐2‐(p‐hydroxyphenyl)ethene by selective reduction of the olefin with sodium boro[3H]hydride. The nitroethene was obtained in one step by condensation of p‐hydroxybenzaldehyde with nitromethane. The produced racemic mixture is to be used in studies regarding the involvement of 1‐nitro‐2‐(p‐hydroxyphenyl)ethane as intermediate in the biosynthesis of tyrosine‐derived cyanogenic glucosides and glucosinolates.
Preparation of a 125I labelled [1,3H]imidazole: 2‐n‐butyl‐4(5)‐125I‐iodo‐5(4)‐hydroxymethylene imidazole
Authors: Bovy Philippe R. , Simmons Richard L.
Published: October 2006

A method for the introduction of 125I in a substituted imidazole has been devised. 2‐n‐Butyl‐4(5)‐hydroxymethylene imidazole undergoes rapid and selective electrophilic substitution on the ring when treated with a halogenating agent such as, i. a., N‐chlorosuccinimide. This reaction has been adapted to the preparation of 2‐n‐butyl‐4(5)‐125I‐iodo‐5(4)‐hydroxymethylence imidazole by treatment of 2‐n‐butyl‐4(5)‐hydroxymethylene imidazole by chloramine‐T in the presence of sodium iodide. The radiolabelled product purified and isolated by HPLC is obtained at a high specific activity (2200Ci/ mmol) with good chemical and radiochemical yields (˜70%).
The synthesis of [4‐3H]oxiracetam ‐ a novel nootropic agent
Authors: Crowe A M , Lawrie K W M , Saunders D , Pfeiffer U
Published: October 2006

The synthesis of [4‐3H]oxiracetam (6) from ethyl 2‐(4‐chloro‐3‐oxo‐butyramido)acetate (1) is described. Ethyl 2‐(4‐chloro‐3‐oxo‐butyramido)‐acetate (1) was reduced with sodium borotritide at Amersham International plc (TR5 tritiation service) to give ethyl 2‐(4‐chloro‐[3‐3H]‐3‐hydroxy‐butyramido)acetate (2). This was elaborated, in four steps, to [4‐3H] oxiracetam (6) in 4.8% overall radiochemical yield, furnishing 5735 μCi, 212 MBq, 41.8 μg, of specific activity 21.7 Ci/mmol, 802.9 GBq/mmol, and radiochemical purity of greater than 98%.
Synthesis of a tri‐tritiated heterobifunctional reagent, a potential tool in photoaffinity labeling technology
Authors: Klotz Ph. , Chatrenet B. , Coppo M. , Rousseau B. , Goeldner M. , Hirth C.
Published: October 2006

The synthesis of the radiolabelled heterobifunctional reagent N‐methyl‐N‐chloroformyl‐N′‐terbutoxycarbonyl‐para‐phenylenediamine A (fig. 1) is presented. In particular, the use of tri‐tritiated methyl iodide in defined reaction conditions allowed the synthesis of this probe B (fig. 1) with a high specific radioactivity (77 Ci/mmol).
Synthesis of high specific activity tritium‐labelled chloroethylcyclohexylnitrosourea and its application to the study of dna modification
Authors: Siew Ernest L. , Habraken Yvette , Ludlum David B.
Published: October 2006

A small‐scale synthesis of high specific activity, N‐(2‐chloro2‐[3H]‐ethyl)‐N′ ‐cyclohexyl‐N‐nitrosourea ([3H]‐CCNU) has been accomplished from tritium‐labelled ethanolamine. The product is pure by TLC and HPLC analysis and has been used successfully to modify DNA. The overall yield on radioactivity including losses in HPLC purification is approximately 4 percent. The availability of this tritium‐labelled compound makes studies of DNA repair and of cellular resistance to N‐(2‐chloroethyl)‐N′ ‐cyclohexyl‐N‐nitrosourea possible.
Synthesis of 5‐(2,3‐ditritiopropoxy)‐3‐(1,2,5,6‐tetrahydropyrid‐4‐yl)indole ([3H]CP‐96,501): A selective ligand for the serotonin (5‐HT1B) receptor
Authors: Macor John E. , Burkhart Carol A. , Lebel Lorraine A. , Koe B. Kenneth , Chalabi Phillip M. , Windels James C. , Roth Robert W.
Published: October 2006

The synthesis of [3H]CP‐96,501 [5‐(2,3‐ditritiopropoxy)‐3‐(1,2,5,6‐tetrahydropyrid‐4‐yl)indole], a selective radioligand for the serotonin (5‐HT1B) receptor and analog of RU‐24,969, is described. 5‐Hydroxyindole is converted in two steps to 5‐(2‐propenyloxy)‐3‐(N‐t‐butoxycarbonyl‐1,2,5,6‐tetrahydropyrid‐4‐yl)indole (3). Hydrogena‐tion or tritiation of 3 followed by removal of the t‐butoxycarbonyl protecting group afforded CP‐96,501 (1a) and [3H] CP‐96,501 (1b), respectively.
Synthesis of 1‐(3,4‐dimethylphenyl)‐1‐[ring‐U‐14C]phenylethane, and of 1‐(3,4‐dimethylphenyl)‐1‐ phenyl[1‐14C]ethane, 14C‐labeled distillate of ecoscint‐OTM, a biodegradable liquid scintillator
Authors: Saito K. , Kurihara N.
Published: October 2006

1 ‐(3,4‐Dimethylphenyl)‐ 1 ‐[ring‐U‐14C]phenylethane, and 1‐(3,4‐dimethylphenyl)‐ 1‐phenyl[1 ‐ 14C]ethane, the 14C‐labeled organic solvents of Ecoscint‐OTM, a so‐called biodegradable scintillation cocktail, were synthesized by simple two‐step reactions on a milligram scale. [Ring‐U‐14C]acetophenone, and [carbonyl‐14C]acetophenone were reduced with NaBH4 at the first step, then the resulting 1‐[ring‐U‐14C]phenylethanol, and 1‐ phenyl[1‐14C]ethanol were condensed with o‐xylene in the presence of H2SO4 at the second step. The radiochemical yield of the overall reaction was 16% on a scale starting with 2 mg of acetophenone, and 70% when 50 mg of acetophenone was added as a carrier.
New technique using [125I]labeled rose bengal for the quantification in blood samples of pipecuronium bromide, a muscle relaxant drug
Authors: Schopfer C. , Pittet J.‐F. , Tassonyi E. , Benakis A.
Published: October 2006

A new technique involving the use of [125I]labeled rose bengal for the quantification of pipecuronium bromide (a muscle relaxant drug) is presented. This technique, which is based on the ability of rose bengal to react with pipecuronium and then form a complex which can be extracted into an organic solvent, involves two steps : the purification and labeling of rose bengal with 125I, and the quantification of pipecuronium. The specific activity of the compound (106 μCi/mg) allows for the quantification of pipecuronium in biological samples at concentrations as low as 5 ng/ml.
The synthesis of the 2H, 3H, and 14C‐isotopomers of 2′‐deoxy‐2′,2′‐difluorocytidine hydrochloride, an anti‐tumor compound
Authors: Wheeler William J. , Mabry Thomas E. , Jones C. David
Published: October 2006

The 2H, 3H, and 14C‐isotopomers of 2′‐deoxy‐2′,2′‐difluorocytidine hydrochloride (1a, gemcitabine hydrochloride) have been synthesized in two radiochemical steps from the reaction of bis‐trimethylsilylcytosine‐[2‐14C] and 3,5‐O‐bis‐benzoyl‐1‐O‐methanesulfonyl‐2‐ deoxy‐2,2‐difluororibose (2b). A mixture of anomers of 3′,5′‐dibenzoyl‐2′‐deoxy‐2′,2′‐difluorocytidine (4a) or its 14C‐isotopomer (4b) were obtained which were readily separated by crystallization from ethyl acetate. Deprotection using methanolic ammonia yielded the target compound. The 2H and 3H‐isotopomers were prepared by deuterium (or tritium) gas hydrogenolysis of 5‐iodo‐2′‐deoxy‐2′,2′‐difluorocytidine (5).
Synthesis and NMR‐analysis of deuterated and tritiated cyclooctyl acetic acid
Authors: Kaspersen Frans M. , Schlachter Irene H. G. , Funke Carel W. , Wagenaars Gerard N. , Mellema Jan‐Remt
Published: October 2006

To increase the bio‐availability of naturally occurring steroids, esterification of the 17‐hydroxy position is a useful approach. Besides (branched) alkanecarboxylic acids1) and cyclohexanecarboxylic acid2) also cyclooctyl acetic acid (1) was applied. To establish the biological fate of the cyclooctyl acetic acid part of steroids the tritiated molecule was synthesized (Figure 1). Cyclooctanone (3) was condensed with cyanoacetic acid3) and the resulting cyanide (4) was hydrolyzed to cyclooctenyl acetic acid (2a)4) which contained according to 1H NMR and 13C NMR 20% of the isomeric 2b(1H NMR (C2HCl3): 5,58 ppm (t, CH of 2a) and 5,63 ppm (br.s CH of 2b) 13C NMR(C2HCl3): 129,6 ppm (CH of 2a) and 115,0 ppm (CH of 2b)).
Syntheses of poly‐deuterated 9(O)‐methano‐Δ6(9α)‐prostaglandin I1 methyl esters
Authors: Tanaka Toshio , Bannai Kiyoshi , Hazato Atsuo , Manabe Kenji , Kurozumi Seizi
Published: October 2006

Two types of poly‐deuterated isocarbacyclin [9(O)‐methano‐Δ6(9α)‐prostaglandin I1] methyl ester have been synthesized for the use of GC‐MS quantitative analysis as internal standards and for the use of metabolic study as substrates. The 5,13,14‐2H3 derivative 2 was prepared via H‐D exchange, deuteroboration, and sodium borodeuteride reduction. The 2,2,3,3,4,4‐2H6 derivatives 3, 4 were prepared starting from tetrahydrofuran‐d8.
Preparation of valeric acids, pentenoic acids, and γ‐valerolactones labelled with deuterium
Authors: Tashiro Masashi , Tsuzuki Hirohisa , Mataka Shuntaro , Yonemitsu Tadashi
Published: October 2006

[2‐2H1]‐, [2,3‐2H2]‐, [2,2,3‐2H3]‐, and [4,4,5,5,5‐2H5]Valeric acids, and trans‐ and cis‐2‐[2‐2H1]pentenoic acid and 4‐[4,5,5‐2H3]pentenoic acid have been synthesized from 2‐bromovaleric acid, trans‐2‐pentenoic acid, 2,3‐dibromovaleric acid, and 4‐pentynoic acid in 78% to 95% isotopic purity by employing Raney alloys or Aluminium powder in alkaline deuterium oxide. The reductions of trans‐3‐ and 4‐pentenoic acids, while smoothly proceeding with 10% Pd‐C as an additive in the reaction system, resulted in the formation of deuteriated valeric acid with over‐introduction of deuterium atoms. Use of 3,4‐dibromo‐valeric acid resulted in the dehydrobromination between C‐2 and C‐3 and the subsequent hydrolysis of the bromine at C‐4, to provide γ‐[2,3‐2H2]‐ lactone, which was also prepared from 4‐bromo‐trans‐2‐pentenoic acid in higher purity. Levulinic acid involves the incorporation of deuterium atoms at C‐3 and C‐5 upon the treatment with 10% NaOD‐D2O, followed by Cu‐Al alloy reduction, affording γ‐[3,3,4,5,5,5‐2H6]valerolactone.
Preparation of 4,4′‐diaminodiphenylmethane‐(2H4) for use as internal standard in the quantification of 4,4′‐diaminodiphenylmethane
Authors: Natangelo Marco , Bagnati Renzo , Fanelli Roberto , Gavinelli Marco , Ulbricht Claudia , Benfenati Emilio
Published: October 2006

A simple method has been developed for the synthesis of 4,4′‐diaminodiphenylmethane‐(2H4) for analytical purposes in gas chromatography‐negative ion chemical ionization mass spectrometry (GC‐NICIMS). It consists in a proton‐deuterium exchange reaction of the diamine using deutero‐hydrochloric acid in deuterated methanol. The reaction was conducted at 60°C. Deuteration of the diamine in the ortho positions of the aromatic rings was observed after eight days in these conditions, using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy.
Catalytic reduction in the synthesis of tritiated (6R) and (6S) 5, 10‐dideaza‐5,6,7,8‐tetrahydrofolate
Authors: Cross Ann D. , Morimoto H. , Williams P. G. , Beardsley G. P.
Published: October 2006

[3H] 5,10‐dideaza‐5,6,7,8‐tetrahydrofolate, DDATHF, was obtained by a two step process. First, 2n[3H2O] was produced in the reaction flask containing m[1HAc] by the reduction of n[PtO2] with 3H2, so that a 1[3H+]:18[3H+ + 1H+] ratio of solvent protic species in theory resulted. Secondly, subsequently added diethyl‐2‐acetyl‐5,10‐dideaza‐9,10‐didehydrofolate was reduced in this tritium labeled solvent with the pre‐reduced Adams catalyst and additional carrier free tritium gas which was introduced to a pressure of 722 torr. The resulting (6R) and (6S) [3H] diastereomers were individually isolated. Each had a specific activity of 11.2 Ci/mmol, and the locations of the incorporated tritium atoms were completely determined by 1H decoupled 320 MHz 3H NMR by comparison with the 300 and 500 MHz 1H NMR spectra of [1H] (6S) DDATHF, [1H] (6R) DDATHF, and [5‐2H (50% 2H), 6‐2H (100% 2H), 7‐2H (50% 2H), 9‐2H (50% 2H), 10‐2H (50% 2H)] (6RS) DDATHF.
Stereoselective synthesis of stable isotope‐labeled L‐α‐amino acids: Biosynthesis of 2H‐, 13C‐, and 15N‐labeled L‐serines
Authors: Hanners John , Gibson Rowena , Velarde Karen , Hammer Judy , Alvarez Mark , Griego Janet , Unkefer Clifford J.
Published: October 2006

We have developed a stereospecific biosynthesis of 13C‐ and 15N‐labeled L‐serine which involves the serine‐type methylotroph Methylobacterium extorquens AM1. In this biosynthesis, C‐3 of serine is derived from methanol while C‐2, C‐1 and the α‐amino group are derived from glycine. By starting with the appropriate labeling precursor, we can produce any of the 2H, 13C and/or 15N isotopomers of L‐serine. Using a 5‐L culture, 40–50 millimoles of L‐serine are produced; L‐serine and glycine are recovered from the growth medium and then separated chromatographically.
Synthesis of the muscle relaxant [14C]L‐637,510
Authors: O'Connor Stephen P. , Ellsworth Robert L. , Gatto Gregory , Sharp Merck , Dohme
Published: October 2006

The synthesis of (E)‐3‐(9‐chloro‐5,6‐dihydro‐1 1 H‐pyrrolo(2,1‐b)(3)‐benzazepin‐11‐ylidene)‐N, N‐dimethyl‐1‐[3‐14C]‐propanamine (Z)‐2‐butenedioate(1:1) (11, [14C]L‐637,510), a potential muscle relaxant product for which 14C‐labeling was required for metabolism studies, is described. Introduction of the label in the 3‐position of the propanamine side chain was accomplished in eight steps from sodium [14C]cyanide with an overall radiochemical yield of 4.8%.
Synthesis of deuterium labelled geosmin and methylisoborneol
Authors: Korth Wolfgang , Ellis John , Bowmer Kathleen
Published: October 2006

Geosmin and methylisoborneol have been synthesised with a fully deuterated methyl group for use as internal standards in water analysis.
Novel selective catalytic reduction with tritium: Synthesis of the GABAA receptor radioligand 1‐(4‐ethynylphenyl)‐4‐[2,3‐3H2]propyl‐2,6,7‐trioxabicyclo[2.2.2]octane
Authors: Palmer Christopher J. , Casida John E.
Published: October 2006

Protection of the terminal alkyne function in 1‐(4‐ethynylphenyl)‐4‐(prop‐2‐enyl)‐2,6,7‐trioxabicyclo[2.2.2]octane with a trimethylsilyl group permits the selective catalytic reduction of the olefin moiety with tritium gas to give after deprotection 1‐(4‐ethynylphenyl)‐4‐[2,3‐3H2]propyl‐2,6,7‐trioxabicyclo‐[2.2.2]octane. The labeled product at high specific activity is an improved radioligand for the GABA‐gated chloride channel of insects and mammals and the intermediate 4‐[2,3‐3H2]propyl‐1‐[4‐[(trimethylsilyl)ethynyl]phenyl]‐2,6,7‐trioxabicyclo[2.2.2]octane is useful for studies on the metabolic activation of this selective proinsecticide.
Regio‐ and stereo‐controlled synthesis of [24,30‐14C]‐labeled‐2,3‐epoxysqualene
Authors: Xiao Xiao‐Yi , Prestwich Glenn D.
Published: October 2006

[24,30‐14C]‐(3S)‐2,3‐Epoxysqualene and its racemate were synthesized by two convenient routes. The products have the label in a metabolically‐nonlabile position relative to the demethylation of lanosterol to cholesterol.
Synthese du Chlorure de 2‐(Dimethylaminophenyl)‐3,6‐Dimethyl Benzo [2‐14C]‐Thiazolium ou Thioflavine T
Authors: Verny M. , Nicolas C. , Veyre A.
Published: October 2006

14C‐Thioflavine T hydrochloride, labelled at the 2‐position of the thiazole ring, is synthesized from 4‐dimethylamino [14CO2H]benzoic acid, obtained from Ba 14CO3. The radiochemical yield is 76 %.
Preparation of [13C2]DMS
Authors: Beerli René , Borschberg Hans‐Jürg
Published: October 2006

An expedient two‐step synthesis of [13C2]DMSO, starting from commercially available [13C]methyl iodide, is described. The product obtained in 57% yield is of high chemical (≥ 99%) and isotopic purity (= 98% 13C2, 2% 13C1), as jugded by NMR‐spectroscopy and a GC‐MS‐assay.
Synthesis of radioiodo‐[4‐(2‐iodo‐4‐fluoro‐benzoyl)piperidin‐1‐yl]‐2′‐acetonaphthone
Authors: Mertens J. , Thomas M.
Published: October 2006

Radioiodo‐[4‐(2‐1‐4‐fluorobenzoyl)piperidin‐1‐yl]‐2′‐acetonaphthone was synthesised as a potential in vivo tracer of the glutamate release inhibiting system. The labeling was performed by Cu1+ assisted non isotopic nucleophilic exchange on [4‐(2‐bromo‐4‐fluorobenzoyl)piperidin‐1‐yl]‐2′‐acetonaphthone.

The labeled compound is obtained after HPLC separation and mini‐column recovery. The brominated substrate is obtained by Kl catalyzed coupling of 2‐bromo‐acetonaphthone to the piperidinyl entity in ethanol at room temperature using triethylamine.
Synthesis of nona‐deutero olivetol and nona‐deutero cannabinoids
Authors: Seltzman Herbert H. , Begum Mosammat K. , Wyrick Christopher D.
Published: October 2006

Copper (I) catalyzed Grignard cross coupling of alkyl bromides provided a facile synthesis of d9‐olivetol [5‐(2,2,3,3,4,4,5,5,5‐2H9)pentyl‐1,3‐benzenediol] with high d9 incorporation levels and no detectable levels of d0 to d7 ions. The outcome of the coupling is dependent on which bromide is used as the Grignard reagent. d9‐Δ9‐THC and racemic d9‐11‐hydroxy‐Δ9‐THC suitable for GC/MS analysis were prepared from the olivetol.
Synthesis of [15N]‐procaine hydrochloride
Authors: Chiriac Maria , Pop Smaranda , Dordea Elisabeta
Published: October 2006

The synthesis of [15N]‐ labelled procaine hydrochloride, using (15NH4)2SO4 as starting isotopically labelled material, is presented. The experimental procedure is an adaptation of the synthesis methods for the corresponding unlabelled compounds.
Synthesis of tritiated threonine with a high specific activity
Authors: Delacotte Jean‐Michel , Galons Hervé , Schott Dominique , Morgat Jean‐Louis
Published: October 2006

The synthesis of the trichloromethyl analogue of benzyloxycarbonyl‐threonine is described. This precursor was reduced by tritium gas to give [methyl‐3H3]‐threonine and its allo isomer. They were separated by HPLC using a chiral stationnary phase. They have a molar specific activity of 3190 GBq/mmol, 86 Ci/mmol.
Synthesis of isotopically labelled 1,1′‐thiobis (2‐chloroethane) and some related compounds
Authors: Harrison J. M.
Published: October 2006

1,1′‐Thiobis (2‐hydroxyethane) has been synthesized isotopically labelled with sulphur‐35, carbon‐13 and deuterium. The conversion to 1,1′‐thiobis (2‐chloroethane) labelled with sulphur‐35 and carbon‐13 is described.
Synthesis of ethyl [14CH3]methylmalonyl thioglycolate as a possible substrate analogue of [14CH3]methylmalonyl coenzyme‐A
Authors: Kovács I. , Kovács Z.
Published: October 2006

Ethyl methylmalonyl thioglycolate is a potential substrate analogue of methylmalonyl‐coenzyme‐A (methylmalonyl‐CoA) in the investigation of propionic acid metabolism. To prove this hypothesis, the tracer ethyl [14CH3]methylmalonyl thioglycolate was synthesized via methyl‐Meidrum's acid to carry out the biochemical examinations. The method described can also be used to synthesize [14CH3]methylmalonyl‐CoA by transesterification of active labelled methylmalonyl thiophenyl ester. This latter intermediate is chemically stable when stored at room temperature, and the unstable [14CH3]methylmalonyl‐CoA can be prepared in one step just preceeding the biochemical experiments.