bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of [methoxy‐3H]‐ and [methoxy‐11C]‐ labelled raclopride. Specific dopamine‐D2 receptor ligands
Authors: Ehrin Erling , Gawell Lars , Högberg Thomas , de Paulis Tomas , Ström Peter 
Published: October 2006

AbstractRadioactive labelled raclopride and its (R)‐isomer were prepared by O‐alkylation of the corresponding phenols with labelled methyl iodide. The syntheses of the two phenolic precursors from (R)‐ and (S)‐2‐aminomethyl‐1‐ethylpyrrolidine are described. Resolution of the racemic amine into the enantiomers was accomplished by fractional crystallization of the ditartrates. Coupling of the amines with 3,5‐dichloro‐2,6‐dimethoxybenzoyl chloride, followed by dealkylation, led to the diphenolic precursors. Mono‐alkylation of the corresponding precursor with [3H]methyl iodide furnished the potent dopamine‐D2 ligand [3H]raclopride and its (R)‐isomer. [11C]Methyl iodide was prepared from [11C]carbon dioxide. Subsequent reaction with phenolic (S)‐precursor furnished [11C]raclopride which has been used in positron emission tomography (PET) studies of the human brain.
Synthesis and stability of S‐(2‐carboxyethyl)‐N‐(2‐t‐butyl‐5‐methoxy‐benzthiazol‐6‐yl)‐[14C]dithiocarbamate [CGP 20376 (CGI 16483)]
Authors: Anjaneyulu B. 
Published: October 2006

AbstractFor pharmacokinetic and metabolism studies in laboratory animals, CGP 20376 labelled with carbon‐14 on the dithiocarbamoyl carbon atom in the side chain at 6‐position of the benzthiazolyl ring system and having a specific activity of 6.13 μCi/mg (2.35 mCi/mmol) was synthesized, in four steps, starting with potassium[14C]thiocyanate. At physiological pH (in vitro) [14C] CGP 20376 dissociated rapidly into its biologically active isothiocyanate precursor [14C] CGP 20308, indicating that it might behave as a pro‐drug.
Synthesis of carbon‐14 labeled 6‐(4‐fluorophenyl)‐5‐(4‐pyridyl)‐2,3‐dihydroimidazo[2,1‐b]thiazole (SK&F 86002)
Authors: Senderoff S. G. , Heys J. R. , Blackburn D. W. 
Published: October 2006

AbstractSK&F 86002, 6‐(4‐fluorophenyl)‐5‐(4‐pyridyl)‐2,3‐dihydromidazo[2,1‐b]thiazole, was synthesized labeled with carbon‐14 at C‐1 or C‐2, 3 using either [14C]thiourea or 1,2‐dibromo [14C2] ethane, respectively. The synthetic route, involving the condensation of an asymmetric benzoin with thiourea followed by alkylation, gave a mixture of SK&F 86002 and structural isomer SK&F 86055, 5‐(4‐fluorophenyl)‐6‐(4‐pyridyl)‐2,3‐dihydroimidazo‐[2,1‐b]thiazole. The two products were separated easily by flash chromatography. The use of 1,2‐dibromo [14C2]ethane as the labeling reagent was superior to the use of [14C]thiourea in this sequence, for the radiolabel was incorporated in the final step of the synthesis by an alkylation reaction, thus providing greatly increased overall radiochemical yields.
Synthesis of 5‐(1′phenyl‐4′‐piperazinomethyl)‐2‐amino‐2‐oxazoline (cor 3224) labelled with carbon‐14
Authors: Luu‐Duc C. , Béney C. , Jarry C. , Feniou C. 
Published: October 2006

AbstractPhenyl‐piperazinomethyl‐amino‐oxazoline 3 labelled with carbon‐14 was obtained in good yield in two steps from [14C]epichlorhydrin. Specific radioactivity: 19.40 μCi/mg; 5,09 mCi/mmol. Radiochemical yield: 50% of the theoretical amount.
The N.C.A. nucleophilic 18F‐fluorination of 1,N‐disubstituted alkanes as fluoroalkylation agents
Authors: Block Dirk , Coenen Heinz Hubert , Stöcklin Gerhard 
Published: October 2006

AbstractThis systematic study describes the preparation of bifunctional n.c.a. 18F‐fluoroalkanes using amino‐polyether (APE) supported nucleophilic substitution. With the APE (Kryptofix® 2.2.2.) potassium carbonate complex in acetonitrile n.c.a. 18F− is introduced into disubstituted alkanes ( X(CH2)nX, n = 1–3, X = Br, OMes, OTos) in high yields within 10–15 min. The substitution yield increases in the sequence of leaving groups Br < OMes < OTos and with increasing alkyl chain length. At substrate concentrations of 0.025 M of bistosyloxyethane a radiochemical yield of 82 ± 8% of [1‐18F]‐fluoroethyltosylate is obtained. This compound appears optimal as fluoroalkylation agent with respect to size, stability and ease of its preparation.
Relative efficiencies of tritium atoms and ionic species in peptide labeling
Authors: Hua Ruoling , Peng Chin‐Tzu 
Published: October 2006

AbstractGlycylglycyl‐L‐leucine and glycyl‐L‐leucine dispersed on silica‐alumina and supported Ni catalyst, were labeled with tritium by microwave discharge activation of tritium gas, as a model to study the optimum condition for labeling peptides and proteins. In the reaction, decreasing the tritium pressure and increasing the microwave power promote the formation of tritium ions and result in an increase in specific activity of the labeled product. The highest specific activity was achieved with the adsorbate molecules as a monolayer on support. Under similar conditions, amino acids glycine and L‐leucine were less efficiently labeled than the peptides. Tritium atoms generated by mercury photosensitization with a uv light were less effective for labeling than tritium ions. Impurities in tritium gas can adversely affect the degree of tritium incorporation in peptides.
Synthesis of high specific activity carbon‐14 labeled PD‐113,926 and CI‐930, potential new cardiotonic agents
Authors: Hays Sheryl J. , Hicks James L. , Huang C. C. 
Published: October 2006

AbstractDouble‐labeled PD‐113,926 and CI‐930 were synthesized from [14C]MeI and [14C]BaCO3 respectively in high specific activity (>90 mCi/mmol). The synthesis of CI‐930 employed the intermediate 2‐butenenitrile‐3,4‐14C2 which was synthesized by a phase transfer Wittig procedure. This Wittig procedure is fast, produces moderate to good yields of olefin and accommodates the use of aqueous solutions of aldehydes.
The syntheses of 4‐aminobutanoic acid‐2,2‐2H2 and ‐4,4‐2H2 and progabide‐2,2‐2H2 and ‐4,4‐2H2
Authors: Davis Bruce 
Published: October 2006

Abstract4‐Aminobutanoic acid‐2,2‐2H2 and ‐4,4‐2H2 were synthesized in high yield with high deuterium incorporation, and then converted into the corresponding deuterium‐labelled anti‐convulsant drug, progabide, by means of a transimination reaction.
Preparation and biodistribution of salicylidene‐aminates (schiff bases) labeled with Tc‐99m
Authors: Vavouraki H. H. , Chiotellis E. , Varvarigou A. 
Published: October 2006

AbstractA series of salicylidene‐aminoacid Schiff bases was synthesized and labeled with Tc‐99m, in neutral pH, using stannous ion as reductant. Labeling yield was greatly affected by concentration‐ratios of the reactants, the optimum concentration ratio being 18.5 × 10−2mmol ligand to 0.4 × 10−2mmol SnCl2 per 4 ml formulation.Various substituents on salicylidene‐phenylalanine molecule or the different amino acids used for the imine formation did not significantly influence the yield of the labeling which usually exceeded 90%. Most of the 99mTc‐chelates exhibited high hepatobiliary affinity, when injected intravenously in mice. Blood clearance as well as hepatic extraction rate varied with the chemical structure of the azomethine derivatives. Urinary elimination was negligible except the hydrophilic complexes 99mTc‐ salicylidene‐isoleucine, 99mTc‐ salicylidene‐cycloleucine and 99mTc‐ salicylidene‐alamine which excreted to the urine as well.
Microelectrochemical radioiodination of monoclonal antibody: A preliminary study
Authors: Wong Z. M. , Teare F. W. , Bowen B. M. , Liao S. K. , Kwok C. S. , Kwong P. C. , Boxen I. 
Published: October 2006

AbstractThe optimal reaction conditions for the microelectrochemical iodination of immunoglobulins were determined with non‐specific human serum immunoglobulins. These conditions were used for the efficient radioiodination of a monoclonal antibody, 140.240, in submilligram quantities. An approximately five‐fold decrease in the titre of the antibody against melanoma cells, as determined by the miniaturized mixed hemadsorption assay, was observed after iodination with an average of 0.85 atoms of iodine per molecule of antibody.
Synthesis of dopexamine hydrochloride labelled with tritium, deuterium and carbon‐14
Authors: Wilkinson D J , Lockley W J S 
Published: October 2006

AbstractDopexamine hydrochloride labelled with carbon‐14 has been prepared by a mixed anhydride reaction between 6‐[[2‐(3,4‐dimethoxyphenyl)ethyl]amino]‐6‐oxohexanoic acid, ethyl carbonochloridate and 2‐phenyl‐[1‐14C]ethylamine. Deuterium isotopomers have been prepared by exchange, reduction of an unsaturated precursor, and by reductive dehalogenation of a chloro‐derivative. Tritium‐labelled compound was obtained by acid‐catalyzed tritium exchange.
Short and convenient synthesis of triethoxy‐[2H]methane and ethoxy‐[2H]methylene malononitrile
Authors: Uray Georg , Celotto Claude 
Published: October 2006

AbstractTriethoxy‐deuteriomethane is synthesized simply from deuterio‐chloroform and monodeuterio‐ethanol. The previously not described ethoxy‐[2H]methylene malononitrile can be prepared from the deuterated orthoester and dideuterio‐malononitrile. Ring closure with acetamidine in ethanol yields 4‐amino‐5‐cyano‐2‐methyl‐[6‐2H]pyrimidine without any loss of deuterium label.
Specific deuteration of phenols and aromatic ethers using boron trifluoride and deuterium oxide
Authors: Banijamali Ali R. , Charalambous Avgui , van der Schyf Cornelis J. , Makriyannis Alexandros 
Published: October 2006

AbstractA number of phenols and aromatic ethers were deuterated in positions ortho and para to the phenolic groups using BF3 etherate followed by quenching with Na2CO3 in D2O. This method involves mild reaction conditions and should have wide applicability in the isotopic labeling of these compounds.
Synthesis of suicide inhibitors of monoamine oxidase: Carbon‐11 labeled clorgyline, L‐deprenyl and D‐deprenyl
Authors: Macgregor R. R. , Fowler J. S. , Wolf A. P. , Halldin C. , Langström B. 
Published: October 2006

AbstractThe suicide inhibitors of monoamine oxidase type A and B, clorgyline and L‐deprenyl have been labeled with carbon‐11 by [11C]methylation of the norbases with [11C]H3I. The less active enantiomer of deprenyl (D‐deprenyl) was also labeled using this procedure. The synthesis time was 35 minutes, the radiochemical yield was 25–40% and the specific activity was 0.8–2.0 Ci/μmol (calculated to EOB). Procedures for synthesis of the precursor norbases as well as the synthesis of unlabeled clorgyline, L‐deprenyl and D‐deprenyl are given.
Synthese Du Metabolite De l'Insecticide Deltamethrine: Alcool Hydroxy‐5 Phenoxy‐3 Benzylique Et De Son Derive Methoxy‐5 Deuteries Et Trities
Authors: Do‐Cao‐Thang  , Nguyen‐Hoang‐Nam  , Hoellinger H. , Nguyen‐Ngoc‐Quang  
Published: October 2006

AbstractPartial hydrolysis of LiBH4 with deuterated, tritiated water in THF solution provided a simple and cheap method for the preparation of deuterated, tritiated alcohols by reduction of esters : (α‐ 2H) and (α‐ 3H) 5‐methoxy‐3‐phenoxybenzyl alcohol, 5‐hydroxy 3‐phenoxybenzyl alcohol (metabolite of deltamethrin, the pyrethroid insecticide).
Synthesis of deuterium labeled cannabinoids
Authors: Banijamali Ali R. , Abou‐Taleb Nageh , Van Der Schyf Cornelis J. , Charalambous Avgui , Makriyannis Alexandros 
Published: October 2006

AbstractSeveral methods for the specific deuteration of cannabinoids are described. Deuteration of the phenolic ring was accomplished by treatment with BF3. Et2O followed by quenching with a solution of Na2 CO3 in D2 O resulting in deuterium incorporation in both the 2 and 4 positions. Regioselective incorporation of deuterium into either the 2 or 4 position of Δ8‐THC was achieved using Florisil spiked with either D2O or H2O. Deuteration at positions 8, 10 and 11 was achieved by addition of DCI gas to the appropriate tetrahydrocannabinol to form 9‐chlorohexahydrocannabinol labeled at either of the above positions, followed by elimination of hydrogen‐ or deuterium chloride with potassium‐tert‐amylate. UV irradiation of specifically labeled Δ8‐THC gave the correspondingly labeled Δ9,11‐THC.
Deuteration of lidocaine
Authors: Hädener Alfons 
Published: October 2006

AbstractStepwise deuteration of the acidic methylene group of lidocaine (1) on a large scale using a moderate excess of 2H2O in triethylamine/pyridine at 200° is described (Table 1). The efficient and economical preparation of bideuterated lidocaine (3) facilitates the use of this compound as an excellent internal standard in lidocaine determination or as a tracer in lidocaine pharmacokinetics.
Synthese von Ferrocen‐ bzw. Rutthenocen‐amphetamin‐analoga und ihre markierung mit 2H bzw. 103Ru
Authors: Wenzel Martin , Preiss Detlef , Gunther Gisela 
Published: October 2006

Abstract1‐Ferrocenyl‐2‐amino‐alkyls were synthezised and labelled with deuterium in the side chain. An additional labelling with deuterium was possible in the alkyl group of the N‐alkyl‐derivatives. By reaction of 103RuCl3 with the ferrocene compounds the ruthenocene analogues were labelled with 103Ru.
Synthesis of tritium labeled 7α‐methoxycarbonyl‐15β,16β‐methylene‐3‐oxo‐17α‐pregn‐4‐ene‐21, 17‐carbolactone, [3H]SH‐D515, a highly selective tracer for the mineralocorticoid receptor
Authors: Nickisch Klaus , Laurent Henry , Schulze Paul‐Eberhard , Grill Hans‐Jörg , Pollow Kunhard 
Published: October 2006

AbstractThe synthesis of 7α‐methoxycarbonyl‐15β,16β‐methylene‐3‐oxo‐17α‐pregn‐4‐ene‐21,17‐carbolactone (5, SH‐D515, ZK 91587), a potent aldosterone antagonist exhibiting a strong and very selective binding to the mineralocorticoid receptor and the tritiated analog 6 is reported.
15N ‐ tomatine
Authors: Elliger Carl A. 
Published: October 2006

AbstractA method for preparative isolation of 15N‐tomatine from foliage of tomato plants grown hydroponically with 15N‐containing nutrient salts is described. Extractive workup of plant material gave a crude product which was chromatographed on Sephadex LH‐20 to yield pure tomatine. Assay of 15N content by mass spectrometry showed that isotopic purity was ca. 95%.
Dual labelling of lobuprofen with tritium and carbon‐14
Authors: Santamaría J. , Rivera P. , Esteban M. , Martin J. L. , Carretero J. M. 
Published: October 2006

AbstractDual labelling of 2‐[4‐(3‐chlorophenyl)‐1‐piperazinyl]ethyl 2‐(4‐isobutylphenyl) propionate (Lobuprofen) with tritium and carbon‐14 was performed. The synthesis between 2‐(4‐isobutylphenyl)propionic acid (Ibuprofen), randomly labelled with tritium, and 2‐[4‐(3‐chlorophenyl)‐1‐piperazinyl]ethanol (C1‐Alkanol) labelled with carbon‐14 in the piperazine ring was achieved. Prior to this synthesis, the [14C]‐Alkanol was obtained using 2‐amino‐[2‐14C]ethanol as a precursor.Purification was accomplished by thin layer chromatography (TLC). Concentration, purity and specific activity of the compound were determined by UV spectrophotometry, high performance liquid chromatography (HPLC) and liquid scintillation techniques.
Specific labelling of putrescine dihydrochloride by heterogeneous hydrogenation with deuterium or tritium gas in dimethyl sulfoxide
Authors: Saljoughian Manouchehr , Morimot Hiromi , Williams Philip G. , Rapoport Henry 
Published: October 2006

AbstractA series of putrescine dihydrochlorides specifically labelled at the 2 and 3 positions have been prepared by hydrogenation of olefinic and acetylenic precursors with deuterium or tritium gas. The olefinic precursor was synthesized by a modification of the Deíépine reaction, and the acetylenic compound in a new, high‐yielding (85%), chemoselective manner. Hydrogenation of the dihydrochloride salts of the precursors was conducted under an atmosphere of T2 or D2 gas, in the presence of Pd‐C catalyst, with DMSO as solvent. Features of this experimental design were that labelling was the final synthetic step, and that removal of the solvent after hydrogenation yielded a pure, crystalline product. 1H, 2H and 3H NMR spectra of the products were recorded immediately after their labelling, and the level of incorporation and positions of the stable and radioactive hydrogens were determined.
Tritiated platinum antitumor agents containing the trans‐(d,1)‐1,2‐diaminocyclohexane carrier ligand
Authors: Wyrick Steven D. , Chaney Stephen G. 
Published: October 2006

AbstractCis‐diamminedichloroplatinum (II) (cisplatin) is one of the most widely used anticancer drugs today. However, platinum compounds possessing the 1,2‐diaminocyclohexane (DACH) carrier ligand offer advantages over cisplatin with regard to bioavailability, activity and decreased renal toxicity. The trans‐(d,1)‐1,2‐diaminocyclohexane derivatives are the isomeric forms recently chosen by the NCI for large animal studies and phase I/II clinical trials. Here we report the synthesis of four trans‐(d,1)‐1,2‐diaminocyclo‐hexane platinum derivatives labeled with tritium in the cyclohexane ring by catalytic reduction of a cyclohexene precursor with carrier‐free tritium gas over 10% Pd/C.
Radioiodinated aliphatic amines as potential pulmonary imaging agents: I. Synthesis of ω‐(4‐[131I]‐iodophenyl)hexylamine and its β‐ and γ‐Methyl substituted analogues
Authors: Gopalakrishnan G. , Lee Y. W. , Man S. F. P. , Noujaim A. A. 
Published: October 2006

AbstractRadioiodinated long chain aliphatic amines which are substrates of pulmonary monoamine oxidase enzyme system are synthesized for evaluation as potential lung imaging agents. ω‐Phenylhexylamine (48% overall chemical yield) and its β‐methyl substituted analogue (17%) were successfully synthesized from β‐phenylhexanoic acid. γ‐Methyl‐ω‐phenylhexylamine (37%) was prepared from ω‐phenylpentanoic acid. Radioiodination of the phenyl moiety of the amines with no‐carrier‐added [131I]‐NaI was achieved via a thallium intermediate with 25%, 31% and 36% radiochemical yield respectively in greater than 98% radiochemical purity (calculated specific activity 20 ‐ 40 TBqmmol−1). Thallation of activated aromatic systems proceeded rapidly and in quantitative yields. Isolation of the thallate intermediate was not necessary.
Synthesis of canrenone and related steroids labelled with tritium, carbon‐14, and sulfur‐35
Authors: Markos Charles S. , Dorn Clifford R. , Zitzewitz Donald J. 
Published: October 2006

AbstractThe synthesis of [1‐3H]canrenone, [1‐3H]spironolactone, [1‐3H]potassium canrenoate, [22‐14C]canrenone, [22‐14C]spironolactone, [22‐14C]potassium canrenoate, and [35S]spironolactone is reported. Tritium labelled compounds were obtained by catalytic reduction of a 3‐keto‐1,4‐diene precursor followed by exchange of enolizable label. Carbon‐14 compounds were obtained by reaction of a 17‐ethynyl steroid with 14CO2. Sulfur‐35 spironolactone was synthesized by the in‐situ generation of [35S]thiolacetic acid from [35S]sodium sulfide.
Labeling of steroids by activated tritium
Authors: Tang G. Z. , Peng C. T. 
Published: October 2006

AbstractSteroid hormones and derivatives are labeled to high specific activities with activated tritium generated by microwave discharge of tritium gas. The steroid nucleus is not degraded by reactions with tritium; the hydroxyl and oxo groups at 3, 11, 17, and 20 positions of the steroid nucleus are not displaced by tritium but are oxidized or reduced to form the labeled by‐products. Saturation of A ring occurs readily, but tritium addition to the isolated CC double bond occurs in the order of Δ1 > Δ4 > Δ5. Steroids with the 21‐hydroxyl group are not tritiated. Despite the addition reaction, the final products from the unsaturated steroids may still contain significant amounts of the labeled parents. Specific activities of the labeled by‐products steroids can approach 29 Ci/mM.
Radioiodinated aliphatic amines as potential pulmonary imaging agents: II. Synthesis of ω‐(4‐[131I]‐iodophenyl)pentylamine and its β‐ and γ‐Methyl substituted analogues
Authors: Lee Y. W. , Gopalakrish G. , Man S. F. P. , Noujaim A. A. 
Published: October 2006

AbstractThe aliphatic amines, ω‐phenylpentylamine and its β‐methyl substituted analogue were synthesized from ω‐phenylpentanoic acid in 34.7% and 28.5% overall chemical yield respectively. γ‐Methyl‐ω‐phenylpentylamine was prepared from ω‐phenylbutyric acid in 39.5% overall chemical yield. Radioiodination of the amines with thallium trifluoroacetate and no‐carrier‐added [131I]‐NaI afforded the corresponding [131I]‐labelled amines in 30%, 28% and 36% radiochemical yield respectively and greater than 98% radiochemical purity (calculated specific activity 20 – 40 TBqmmol−1). The position of iodination was established by proton magnetic resonance to be para to the alkyl chain.
(All Z)‐4,7,10, 13‐nonadecatetraen‐1‐ol 4‐methylbenzene sulfonate: Preparation and use in a one‐step synthesis of arachidonic acid labeled with carbon‐14
Authors: Liu Yu‐Ying , Minich Martha 
Published: October 2006

AbstractA key precursor to carbon‐14 labeled arachidonic acid, namely (all Z)‐4,7,10, 13‐nonadecatetraen‐1‐ol 4‐methylbenzene sulfonate, was synthesized in 7 steps from 1‐heptyne, 1,4‐dichloro‐2‐butyne and propargyl alcohol and it was purified to be free of other isomers. The availability of this compound, which can be successfully stored, allows the repeated preparation of arachidonic‐1‐14C acid in isotopically and chemically pure form by a simple one‐step carbonation reaction of the readily prepared corresponding bromide. The labeled arachidonic acid is obtained at 100% chemical and radiochemical purity.
Synthesis of [8,9‐3H2]‐(7S)‐methoprene, a juvenile hormone analog, by selective reduction of a protected trienoate
Authors: Boehm Marcus F. , Prestwich Glenn D. 
Published: October 2006

AbstractHigh specific activity 3H‐(7S)‐methoprene is prepared in seven steps from (3S)‐citronellol by the use of iron tricarbonyl to protect the dienoate moiety of isopropyl (2E,4E)‐3,7,11‐trimethyl‐2,4,8‐dodecatrienoate during heterogeneous tritiation of remote olefinic bond.
Preparation of 14C‐labeled 8,9‐didehydro‐6,8‐dimethyl‐2‐methylthioergoline mesylate, a dopamine antagonist potentially useful in the treatment of schizophrenia
Authors: Wheeler William J. 
Published: October 2006

AbstractWe have prepared 14C‐labeled 8,9‐didehydro‐6,8‐dimethyl −2‐methylthioergoline mesylate (LY 170542), a dopamine antagonist potentially useful as an anti‐psychotic. The 14C‐label was introduced via a novel application of the Wittig reaction on 1‐(4′‐toluene‐ sulfonyl) −8,9‐didehydro‐6‐methyl‐ergolin‐8‐one and subsequent reduction of 1‐(4′‐toluenesulfonyl)‐17‐[14C]‐lysergene by lithium/ammonia at −33°C. The 17‐[14C]‐agroclavine thus prepared was converted into 17‐[14C]‐LY 170542 by reaction with methanesulfenyl chloride/methanesulfonic acid.
Enzymatic synthesis of carbon‐11 acetyl coenzyme A
Authors: Mannens Geert , Slegers Guido , Lambrecht Raf , Goethals Patrick 
Published: October 2006

AbstractAn enzymatic synthesis of [11C]acetyl coenzyme A from [1‐11C]acetate is described. 11CO2 was reacted with methylmagnesium bromide in diethyl ether at 0°C. The excess of Grignard reagent was hydrolyzed by adding methanol. After evaporation of the solvents, the residue was redissolved in hydrochloric acid and [1‐11C]acetic acid was removed by acid distillation. In the presence of cofactors the [1‐11C] acetic acid was sent over an enzyme reactor containing immobilized acetyl coenzyme A synthetase (Acetate : CoA ligase (AMP forming) EC 6.2.1.1).
Synthesis of 4‐ (methylnitrosamino)‐1‐ (3‐pyridyl)‐1‐butanone, 4‐ (carbethoxynitrosamino)‐1‐ (3‐pyridyl)‐1‐butanone, and N′ ‐nitrosonornicotine labelled with tritium in the pyridine ring
Authors: Wiley James C. , Chien David H. T. , Nungesser Nancy A. , Lin Dorothy , Hecht Stephen S. 
Published: October 2006

AbstractThe carcinogenic tobacco‐specific nitrosamines 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK) and N′‐nitrosonornicotine (NNN), as well as the model compound 4‐(carbethoxynitrosamino)‐1‐(3‐pyridyl)‐1‐butanone, were synthesized with tritium at the 5‐position of the pyridine ring. In each case, the tritium labelled compound was prepared by catalytic tritium replacement of the corresponding brominated precursor.