bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of iminodiacetic acid derivatives of ortho and meta amino hippuric acid analogs as renal function agents
Authors: Bhargava Kuldeep K. , Zhang Zhuangyu , Chun Sam B. , Chervu L. Rao , Blaufox M. Donald 
Published: October 2006

AbstractIminodiacetic acid derivatives of meta amino hippuric acid (MAHIDA) and ortho amino hippuric acid (OAHIDA) have been synthesized in the course of our continuing investigation of 99mTc‐labeled hippuric acid analogs for application for renal function measurements. The two derivatives yielded stable 99mTc complexes using Sn(II) reduction method and are excreted rapidly via the GU tract as shown in animal biodistribution studies. Clearance of these two complexes is lower than that of the analog formed with para amino hippuric acid (PAHIDA) previously reported. Some aspects of structure activity relationship associated with PAHIDA point to the fact that para derivative has optimal renal excretory characteristics.
[3H]‐labelling of hydroxyethyl groups – synthesis of s‐2‐hydroxy [2‐3H] ethyl) glutathione and of [3H]‐melphalan
Authors: Verny M. , Nicolas C. 
Published: October 2006

AbstractThe easy preparation of 2‐bromo [1‐3H] ethanol allows the tritium labelling of molecules bearing S‐ or N‐ hydroxyethyl groups. Thus S‐(2‐hydroxy [2‐3H] ethyl) glutathione and [3M]‐Melphalan were synthesised with specific radioactivities of around 10 mCi/mmol (370 MBq/mmol). These values could be theoretically raised to 10 Ci/mmol (370 GBq/mmol), according to the specific activity of the labelling precursor, sodium [3H] borohydride.
Synthesis of 14C‐ and 35S‐labelled 2‐mercaptobenzimidazoles
Authors: Doerge Daniel R. 
Published: October 2006

Abstract14C‐ and 35S‐labelled 2‐mercaptobenzimidazole and 1‐methyl‐2‐mercaptobenzimidazole were synthesized from 14C‐carbon disulfide, 35S‐thiourea, 14C‐methyl iodide and 35S‐thiourea, respectively, for use in studies on the mechanism of action of antithyroid drugs. The products were purified by chromatography on silica and isolated with radiochemical purities of greater than 98%, yields of 45‐77% and specific activities of 2.1‐5.3 mCi/mmole.
A convenient synthesis of CIS/trans‐3‐chloroacrylic acid‐UL‐14C
Authors: Roth G. A. , McKendry L. H. 
Published: October 2006

AbstractA convenient method for oxidation of allylic alcohols to the corresponding carboxylic acids is described. A two phase (methylene chloride/aqueous) silver oxide oxidation circumvents isolation of the intermediate aldehydes, thus making the procedure well suited to microscale carbon‐14 synthesis. Although we required a mixture of cis/trans‐3‐chloro‐acrylic acid‐UL‐14C and thus began the preparation with cis/trans‐3‐chloroallyl alcohol‐UL‐14C, the reaction sequence can be carried out starting with either isomer to provide the isomerically pure carboxylic acids.
Synthesis of 13C‐ and 14C‐Labeled methanesulfinic and methanesulfonic acids
Authors: Feil V. J. , Huwe J. K. , Dulik D. M. , Fenselaum C. 
Published: October 2006

AbstractThe enzyme catalyzed displacement of the methyl sulfonyl group from pentachlorophenyl methyl sulfone, the m‐chloroperoxybenzoic acid oxidation of methyl mercaptan and the reaction of methyllithium with sulfur dioxide are methods described for the synthesis of isotopically labeled methanesulfinic acid. The first two methods can be carried out on a milligram scale and are suitable for high specific activity preparations while the latter method is suitable for preparations on a gram scale. Conditions are also given for the preparation of isotopically labeled methanesulfonic acid.
Synthesis of [3H]clozapine
Authors: De Paulis Tomas , Davis Daniel A. , Smith Howard E. , Malarek David H. , Liebman Arnold A. 
Published: October 2006

Abstract[3H]Clozapine was prepared with a specific activity of 9.9 Ci/mmol by reaction of 8‐chloro‐11‐(methylthio)‐5H‐dibenzo[b,e][1,4]diazepine with an excess of [3H]N‐methylpiperazine. The latter was prepared from N‐methylpyrazinium bromide in ethanolic hydrogen chloride by reduction at room temperature with tritium over 5% rhodium on aluminum oxide.
The synthesis of 3H‐putrescine and subsequent biosynthesis of 3H‐jacobine, a pyrrolizidine alkaloid from Senecio Jacobaea
Authors: Reed R. L. , Buhler D. R. 
Published: October 2006

AbstractA new method was developed for the preparation of tritiated putrescine dihydrochloride ([2,3‐3H]‐1,4‐diaminobutane dihydrochloride) from succinonitrile (1,4‐butanedinitrile) and 3H2O, with a radiochemical yield of 16%. Tritiated jacobine and other pyrrolizidine alkaloids were then biosynthesized in Senecio jacobaea using 3H‐putrescine·2HC as the precursor with a radiochemical yield of 0.9% into total pyrrolizidine alkaloids. Jacobine accounted for 36% of the total. This synthetic method provides a relatively inexpensive source for the preparation of these labelled compounds.
Marquage par 14C du Chloro‐2 Ethyl Isocyanate. Application au Marquage de Chloroethyl Tetrazinone et de Chloroethylnitrosourees
Authors: Madelmont J. C. , Moreau M. F. , Godeneche D. , Labarre P. , Veyre A. 
Published: October 2006

AbstractLe chrloro‐2 éthyl isocyanate a étémarqué par 14C sur le groupe carbonyl à partir de l'acide chloropropionique‐14C.La réaction de Curtius en présence de catalyseur de transfert de phase a été utilisée.Les marquages de chloro‐2 éthyl tetrazinone et de chloro‐2 ethyl nitrosourées sont décritis.
Synthesis of D‐[1‐14C]penicillamine hydrochloride
Authors: Chien David H. T. , Ebert David A. , Roth Robert W. 
Published: October 2006

AbstractMethods are described for the synthesis of DL‐[1‐14C]penicillamine and D‐[1‐14C]penicillamine hydrochloride from K14CN. The method consists of additon of H14CN to 2,2,5,5‐tetramethyl‐3‐thiazoline followed by hydrolysis of the resulting thiazolidine to DL‐penacillamine. Resolution was achieved through the salt of N‐formylisopropylidene‐DL‐penicillamine with (−)‐norephedrine. The specific activity of D‐penicillamine was 21.7 mCi/mmole and the overall radiochemical yield from K14CN was 3.3%.
Radioactively labelled epoxides. Part VI. tritium‐labelled mono‐ and dimethyl substituted phenyl oxiranes (styrene oxides)
Authors: Setiabudi Frans , Oesch Franz , Platt Karl L. 
Published: October 2006

AbstractTritium‐labelled (E)‐ and (Z)‐2,3‐dimethyl‐2‐phenyl oxirane 4, (E)‐ and (Z)‐2‐methyl‐3‐phenyl oxirane 7 and 2,2‐dimethyl‐3‐phenyl oxirane 11 have been prepared by reduction of the corresponding bromoketones with sodium borotritide to the corresponding bromohydrins followed by cyclization to the oxiranes. These oxiranes were successfully used as diagnostic substrates to distinguish between different forms of epoxide hydrolase and glutathione transferase.
Synthese d'Acide Benzisoxazole‐1, 2 Acetique‐3 (14C‐α) et (14c‐β)
Authors: Thourel P. , Noel J. P. , Beaucourt J. P. 
Published: October 2006

AbstractNous décrivons dans ce travail. deux synthèses de l'acide benzisoxazole‐1,2 acétique‐3 marqué respectivement au carbone 14 en positions α et ß. L'acide 14C‐α est obtenu à partir d'hydroxy‐4 coumarine (14C‐3) synthétisée à partir d'hydroxy‐1 acétophénone (14C‐CH3) obtenue par réaction de Fries.L'acide 14C‐ß est synthétisé à partir d'hydroxy‐4 coumarine 14C‐2 obtenue à partir de carbonate d'éthyle 14C. Les positions de marquage ont été contrǒlées par spectrométrie de masse et ont confirmé le schéma réactionnel supposé du réarrangement en acide benzisoxazole‐1,2 acétique‐3.
Synthetic studies with [18F]p‐fluorobenzenediazonium chloride application to the synthesis of a radiolabelled glucocorticoid: [18F]WIN 44577
Authors: Feliu Anthony L. 
Published: October 2006

AbstractA, route was devised to synthesize no‐carrier‐added or carrier‐added [10F]p‐fluorophenylhydrazine from aqueous [18F]fluoride. Key reaction in this three‐step sequence is the reduction of [18F]p‐fluorobenzenediazonium chloride with sodium cyanoborohydride. The utility of this method is demonstrated by the synthesis of [10F]WIN 44577, an N‐(pfluorophenyl)pyrazole‐containing corticosteroid, which exhibits exceptionally high in vitro binding affinity for type‐II glucocorticoid receptors, and which is currently under evaluation as a possible radioligand for positron emission tomographic studies.
Asymmetric tritiation of N‐acetyl α‐β dehydrotryptophanamide
Authors: Pinto‐Alphandary H. , Van Craeynest‐Jimonet C. , Morgat J. L. , Fromageot P. 
Published: October 2006

AbstractRhodium‐DiPAMP complex catalyzes the stereoselective addition of two tritium atoms on N‐acetyl −α −β dehydrotryptophanamide. The substrate was prepared by dehydrogenation of N‐acetyltryptophanamide with TSO (Tryptophan‐Side Chain oxidase) from Pseudomonas. Tritiated N‐acetyl‐tryptophanamide was obtained with the theoretical specific radioactivity (58 Ci/mmole). The enantiomeric excess of the L‐diasteroisomer reached 94.4 %. 3NMR spectra indicated the selectivity of 3H‐labelling on the Cα – Cβ double bond. This new approach of tritiation by homogeneous catalysis applied to tryptophanyl‐containing peptides is discussed.
Synthesis of acetaminophen‐d4
Authors: Johnston D. , Elder D. 
Published: October 2006

AbstractA synthetic procedure for acetaminophen‐d4 (4′‐hydroxyacetanilide – 2′,3′,5′,6′‐d4) is described. The preparation was achieved in two steps from nitrobenzene‐d5 in an overall yield of 40%.
Preparation of folic acid specifically labeled with deuterium at the 3′,5′‐positions
Authors: Gregory Jesse F. , Toth John P. 
Published: October 2006

AbstractA method was devised for the synthesis of 3′,5′‐[2H2]folic acid (d2‐folic acid) for use in studies of folate metabolism in human beings. Labeling was accomplished by catalytic dehalogenation of 3′,5′‐dibromofolate with deuterium gas and palladium/carbon catalyst. d2‐Folic acid was separated from reduced forms and residual 3′‐monobromofolate by chromatography on DEAE‐Sephadex. Analysis by proton NMR and mass spectrometry indicated 70–75% deuteration of the 3′,5′‐positions and lack of deuteration at other carbons.
A convenient synthesis of D‐[1‐11C]glucopyranose and D‐[1‐11C]galactopyranose using diborane
Authors: Tada Masao , Oikawa Atsushi , Matsuzawa Taiju , Itoh Masatoshi , Fukuda Hiroshi , Kubota Kazuo , Kawai Hiroaki , Abe Yoshinao , Sugiyama Hiroshi , Ido Tatsuo , Ishiwata Kiichi , Iwata Ren , Imahori Yoshio , Sato Tachio 
Published: October 2006

AbstractRapid chemical syntheses of D‐[1‐11C]glucopyranose and D‐[1‐11C]galactopyranose starting from D‐arabinopyranose and D‐lyxopyranose, respectively, are described. The use of diborane for reduction of intermediates in highly effective for reducing the time required.
Synthesis of [carbonyl‐14C]hexopal
Authors: Johnston D. , Elder D. 
Published: October 2006

AbstractA synthetic procedure for producing [carbonyl‐14C]Hexopal (mesoinositol [carbonyl‐14C]nicotinate) is described. The synthesis is achieved in two steps using [carbonyl‐14C]nicotinic acid as the source of the radiolabel with an overall chemical yield of 75% and a radiochemical yield of 67%.
Near‐quantitative conversion of labelled acids to esters by modified hassner esterification. Synthesis of labelled triglycerides
Authors: Elbert Tomáš 
Published: October 2006

AbstractThe modification of the reaction conditions of Hassner esterification ‐ DCC/4‐dimethylaminopyridine method ‐ merely the gradual addition of DCC to the reaction mixture ‐ eliminated the unwanted side reaction ‐ N‐acyl‐N,N'‐dicyclohexylurea formation ‐ and thus improved the conversion of the acid to the desired ester. Glycerol tri[U‐14C]palmitate, glycerol tri[U‐14C]oleate and glycerol tri[9, 103H]stearate with molar activities greater than 1800 MBq.mmol−1 were prepared with preparative radiochemical yields about 86–92%.
The oxidative cleavage of amines by iodine monochloride
Authors: Ghaffari M. A. , Ali H. , Van Lier J. E. 
Published: October 2006

AbstractThe formation of secondary products during the radioiodination of aromatic amines is reported. Iodination of a series of N,N‐dimethyl‐N'‐(alkylphenyl)‐1,3‐propanediamines with IC1 in the presence of AcOH and HClO4 gave in addition to the expected iodo derivatives substantially amounts of secondary cleavage products which were identified as the corresponding iodobenzaldehyde derivatives.
Synthesis of carbon‐13 and carbon‐14 labeled paldimycin tri‐sodium salt
Authors: Hsi Richard S. P. , Witz Dennis F. , Visser Jeronimo , Stolle Wayne T. , Ditto Cathy L. 
Published: October 2006

AbstractCarbon‐14 labeled paldimycin trisodium salt was prepared by addition of N‐acetyl‐L‐cysteine to [14C]paulomycin, the radioactive antibiotic produced by fermentation of Streptomyces paulus in the presence of L‐methionine labeled with carbon‐14 in the S‐methyl group Carbon‐13 nuclear magnetic resonance (NMR) spectra of paulomycin produced when the fermentation was carried out in the presence of L‐[S‐methyl‐13C]methionine showed that isotope incorporation had occurred specifically at the methoxy group of ring C, i.e., the 2‐deoxy sugar portion of paulomycin. With sustained slow feed of labeled precursors during the optimum antibiotic production period, carbon‐14 isotope yields of up to 17.5% with specific activity of up to 11.4 μCi per milligram of paulomycin, and carbon‐13 isotope yields of up to 24% with 17‐fold isotope enrichment over natural abundance, were achieved.
The synthesis of deuterium‐labelled 2‐bromoethanol, acrylonitrile, acrylamide, 2‐aminoethanol, 2‐bromoethylamine hydrobromide and 1‐bromo‐2‐chloroethane
Authors: Bird Ian , Farmer Peter B. 
Published: October 2006

AbstractMethods are described for the synthesis of C [2H4]‐2‐bromo‐ethanol, [1‐2H2]‐2‐bromoethanol, [2‐2H2]‐2‐bromoethanol, [2H3]‐acrylonitrile and [2H3]‐acrylamide from 2‐benzyloxyacetic acid. In the synthesis of [1‐2H2]‐1‐bromo‐2‐chloroethane and [2‐2H2]‐1‐bromo‐2‐chloroethane from chloroacetonitrile via deuterated 2‐aminoethanol and [1‐2H2]‐2‐bromoethylamine hydrobromide or [2‐2H2]‐2‐bromoethylamine hydrobromide some randomisation of the halogens occurred, and difficulties were experienced in preparing isotopically pure products.
Preparation du (+)‐Cis‐isobutyl‐3 dimethyl‐2,2 cyclopropane carboxylate de benzyl‐5 furylmethyle‐3 tritie, derive du pyrethrinoide (+)‐cismethrine
Authors: Thang Do‐cao‐ , Nam Nguyen‐hoang‐ , Hoellinger H. 
Published: October 2006

AbstractThe catalytic reduction of (+)‐cismethrin 1, a synthetic pyrethroid, with tritium gas in various solvents and in presence of different catalysts was studied. The best result was obtained with 5% Pd‐ BaSO4 catalyst in methanol giving rise to 3H‐5‐benzyl‐3‐furylmethyl (+)‐cis‐3‐isobutyl‐2,2‐dimethylcylopropane carboxylate 2 with a specific activity of 98 Ci. mmol−1 (3626 GBq. mmol−1). The incorporation of tritium was verified by H‐NMR and MS analyses.
Tritium labelling of cholest‐4‐en‐3‐one by catalytic debromination of 2,2‐6B‐tribromo‐cholest‐4‐en‐3‐one
Authors: Römer J 
Published: October 2006

AbstractThe catalytic debromination of 2,2,6ß‐tribromo‐cholest‐4‐en‐3‐one with tritium gas (T2) yields tritium‐labelled cholest‐4‐en‐3‐one of high specific activity. The most favourable reaction parameters are reported. Using tritium‐hydrogen (TH) gas mixtures the labelling reactions are accompanied by three kinetic isotope effects the importance of which is discussed.
Tritium Labelled 1‐O‐Octadecyl‐2‐O‐methyl‐rac‐glycero‐3‐phosphocholine (ALP) and 1‐S‐Hexadecyl‐2‐O‐ethyl‐rac‐thioglycero‐3‐phosphocholine (Thio‐ALP)
Authors: Wyrick Steven D. , Surles Jefferson R. , Morris‐Natschke Susan , Piantadosi Claude , Modest Edward J. 
Published: October 2006

AbstractThe phospholipids, ALP and Thio‐ALP, are non‐hydrolyzable analogues of platelet activating factor (PAF). Interest in ALP and thio‐ALP centers upon their activity as potential antineo‐plastic agents. A variety of mechanisms of action have been attributed to these compounds including inhibition of a phospholipid cofactor of a phospholipid sensitive Ca+2‐dependent protein kinase. Thio‐ALP is at least as active as a growth inhibitor of the HL‐60 promyelocytic leukemic cell line as is ALP‐the most active reference analogue reported in the literature and is approximately twice as active against the BG‐1 and BG‐3 human ovarian carcinoma cell lines. To aid in further biochemical studies, we report the synthesis of high specific activity tritium labelled ALP and thio‐ALP. These products were obtained by palladium catalyzed reduction of 1‐0‐octadecenyl and l‐S‐hexadecenyl precursors with carri'er‐free tritium gas.
Synthesis of adinazolam mesylate multiply labeled with carbon‐13 and deuterium
Authors: Hsi Richard S. P. , Stelzer Lindsay S. 
Published: October 2006

AbstractAdinazolam mesylate labeled with stable isotopes was synthesized for conducting bioavailability studies. Adinazolam labeled uniformly with carbon‐13, >99% enrichment, in the unsubstituted phenyl ring was prepared for administration as drug. In addition, adinazolam was also dual‐labeled with carbon‐13, as in the drug, and with deuterium, six atoms per molecule, in the N‐methyl groups. The double‐labeled material was prepared for use as an internal standard in the mass spectral assay procedure to be employed in the study.
d,l‐6a‐13C‐Glaucine 1.5 phosphate
Authors: Henton Daniel R. , Goralski Christian T. , Heeschen Jerry P. , Nyquist Richard A. , Pfeiffer Curtis D. 
Published: October 2006

Abstractd, l‐Glaucine 1.5 H3PO4, is a non‐narcotic antitussive for which a sample of carbon‐13 labelled material was required for metabolism studies in humans. The sample of 99% enriched d, l‐6a‐13C‐glaucine 1.5 H3PO4 was prepared in 7 steps in 36% overall yield starting with purchased 99% enriched 1‐13C‐papaverine. The papaverine was N‐methylated with methyl iodide and the resulting methiodide reduced to d, l‐1‐13C‐laudanosine with sodium borohydride. The laudanosine was O‐demethylated with 48% HBr and cyclized to d, l‐6a‐13C‐1,2,9,10‐tetrahydroxyaporphine (THA) using aqueous ferric chloride/sodium acetate and isolated as the hydrochloride salt (THA ± HCl). The THA ± HCl was converted to the free base and remethylated with phenyltrimethylammonium hydroxide. The resulting d, l‐6a‐13C‐glaucine was purified by column chromatography and isolated as the hydrobromide salt. The d, l‐6a‐13C‐glaucine 1.5 H3PO4 was obtained by conversion of the hydrobromide to the free base and treatment with 85% phosphoric acid in ethanol.
Synthesis of non‐bridging 18O3 labeled phosphate monoesters
Authors: Calvo Kim C. 
Published: October 2006

AbstractA new method is reported for the synthesis of tri‐18O substituted phosphate monoesters where the phosphoryl oxygen ester bond is 16O. The method relies on the reactivity of trivalent phosphorus toward hydrolysis and oxidation to produce dimethyl [18O3]‐phosphorochloridate with a minimal excess of labeled water. This chlorophosphate diester can be used to prepare a wide variety of phosphate monoesters where the three peripherial oxygens are labeled.
Synthesis of carbon‐13 and carbon‐14 labelled triazolo‐1,4‐benzodiazepines
Authors: Banks William R. , Hawi Amale A. , Digenis George A. 
Published: October 2006

AbstractAn efficient two‐step synthesis of 8‐chloro‐1‐methyl‐6‐phenyl‐[3H]‐S‐triazolo‐[4,3‐a][1,4]‐benzodiazepine (alprazolam) and 8‐chloro‐6‐(2‐chlorophenyl)‐1‐methyl‐[3H]‐S‐triazolo‐[4,3‐a][1,4]‐benzodiazepine (triazolam) labelled with carbon‐13 or carbon‐14 from their corresponding hydrazines is reported. The method involves acylation of the appropriate hydrazine using the mixed carbonic anhydride of sodium [13C] or [14C] acetate and isobutylchloroformate under mild conditions. Thermolysis of the resulting acetylhydrazides gave the target carbon‐14 and carbon‐13 labelled compounds in good yields.
Synthesis of deuterium‐labellec alkenes
Authors: Sirokán G. , Molnár Á. , Bartók M. 
Published: October 2006

AbstractNovel or improved synthesis of six deuterated 1‐alkenes (1‐hexene‐[3,3‐2H2], 5‐methyl‐1‐hexene‐[3,3‐2H2], 1‐pentene‐[1,1,2‐2H3], 1‐hexene‐ [2‐2H], 1‐hexene‐[1,1,3,3‐2H4] and 1‐hexene‐[1,1,2,3,3‐2H5]) are reported. The isotopic purities of these labelled alkenes were 99, 99, 92, 99, 76 and 86%, respectively.
Syntheses of [6‐14C] and [5‐carboxy, 6‐14C2]nitrendipine
Authors: Maul W. , Scherling D. 
Published: October 2006

Abstract[6‐14C]Nitrendipine synthesis started from barium[14]carbonate, which was converted to [1‐14C]acetyl chloride. The acid chloride was condensed with Meldrum's acid (2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione). The resulting intermediate was treated with boiling methanol to give methyl [3‐14C]acetoacetate. The reaction with gaseous ammonia in toluene yielded the corresponding methyl 3‐amino[3‐14C]crotonate which was condensed with ethyl 2‐(3‐nitro‐benzylidene) acetoacetate to obtain [6–14C]nitrendipine.[5‐carboxy, 6‐14C2]Nitrendipine was synthesized by an analogous procedure starting from methyl [1,3‐14C2]acetoacetate.
Purification of 3H‐dihydroalprenolol by two dimensional thin layer chromatography
Authors: Smisterová Jarmila , Soltés Ladislav , Kállay Zoltan 
Published: October 2006

AbstractA two dimensional thin‐layer chromatographic method developed for the purification and analysis of (‐)‐[3H]dihydroalprenolol, by using an acidic mobile phase (butanol/water/acetic acid 25:10:4, v/v) in one direction and a basic eluent (chloroform/acetone/tri‐ethylamine 50:40:10, v/v) in another direction.
A synthon for C‐20 trideuterated eicosanoids: Preparation of [2H3]‐arachidonic acid
Authors: Prakash Chandra , Saleh Samir , Sweetman Brian J. , Taber Douglass F. , Blair Ian A. 
Published: October 2006

AbstractStarting from hex‐5‐yn‐1‐ol an efficient seven step synthesis of (Z)9‐[2H3](non‐3‐en‐1‐yl) triphenylphosphonium bromide is described. This Wittig reagent is a key intermediate for the synthesis of C‐20 trideuterated eicosanoids. Introduction of deuterium at C‐20 provides standards that are stable to a wide range of reagents and reaction conditions. The utility of the Wittig synthon was demonstrated by the preparation of C‐20 trideuterated arachidonic acid.
Synthesis of γ‐amino[4‐11C]butyric acid (GABA)
Authors: Antoni Gunnar , Långström Bengt 
Published: October 2006

AbstractA one‐pot synthesis of no‐carrier added γ‐amino[4‐11C]butyric acid (GABA) starting with hydrogen [11C]cyanide prepared from [11C]carbon dioxide, is presented. Hydrogen [11C]cyanide was trapped in tetrahydrofuran/potassium hydroxide in the presence of the amino polyether Kryptofix 2.2.2. A Michael addition with ethyl acrylate followed by a selective reduction and hydrolysis of the resulting amino ester gave [4‐11C]GABA. The radiochemical purity of GABA was higher than 99% and the decay corrected radiochemical yield was 60–65% based on the amount of H[11C]CN used. The total synthesis time including purification was around 40 min, counted from the start of the Michael addition reaction.
Synthesis of carbon‐13 labeled ibuprofen
Authors: Hsi R. S. P. , Stelzer L. S. , Stolle W. T. 
Published: October 2006

AbstractThis report describes the synthesis of ibuprofen of labeled with carbon‐13 either at the terminal methyl carbons, or at the methine carbon of the isobutyl side chain. The synthetic route involves the removal of the isopropyl group in the isobut I side‐chain of ibuprofen via 2‐[4‐(2‐methyl‐1‐propenyl)phenyl] propionic acid followed by restoration of the isopropyl group with a Wittig reaction, using appropriate carbon‐1 3 labeled acetone as the precursor of the isopropyl group. Interesting NMR coupling data attributable to phosphorous and carbon‐13 are presented in the experimental section.