bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regiospecific synthesis of polychlorinated dibenzofurans with chlorine‐37 excess
Authors: Chang Yoon‐Seok , Deinzer Max L. 
Published: October 2006

AbstractThe synthesis of regiospecifically chlorine‐37 labeled di‐ and trichlorodibenzofurans is described. The strategy for introducing a chlorine‐37 label regiospecifically has been to reduce the nitro derivative to the corresponding amine. The amine is converted to the diazonium salt with t‐butyl nitrite, and this product is converted to the final product via the Sandmeyer reaction with chlorine‐37 labeled cuprous chloride.
Radioiododestannylation. Convenient synthesis of a high affinity thromboxane A2/prostaglandin H2 receptor antagonist
Authors: Mais Dale E. , Halushka Perry V. , Naka Masao , Morinelli Thomas A. , Oatis John E. , Hamanaka Nobuyuki 
Published: October 2006

AbstractRadioiodination of methyl‐7‐[(2R, 2S, 3S, 5R)‐6,6‐dimethyl‐3‐(4‐trimethylstannylbenzenesulfonylamino) bicyclo[3.1.1]hept‐2‐yl]‐5(Z)‐heptenoate with [125I] Na using a modification of the chloramine‐T method in organic solvent is simple with high yields and site specific. The product, following hydrolysis of the ester, 7‐[(2R, 2S, 3S, 5R)‐6,6‐dimethyl‐3‐(4‐[125I]‐iodobenzenesulfonylamino) bicyclo[3.1.1]hept‐2‐yl]‐5(Z)‐heptenoic acid ([125I]‐ISAP), was purified by HPLC. The high specific activity and specific binding will make the ligand a useful tool for the characterization of thromboxane A2/prostaglandin H2 receptors.
Syntheses of 18F‐labeled reduced haloperidol and 11C‐labeled reduced 3‐N‐methylspiperone
Authors: Ravert Hayden T. , Dannals Robert F. , Wilson Alan A. , Wong Dean F. , Wagner Henry N. 
Published: October 2006

Abstract18F‐Labeled reduced haloperidol and 11C‐labeled reduced 3‐N‐methylspiperone were synthesized in a convenient and quantitative one step reduction from 18F‐labeled haloperidol and 11C‐labeled N‐methylspiperone, respectively. Both products were purified by semipreparative HPLC and were obtained at high specific activity and radiochemical purity.
Preparation of [123I]‐ and [125I]epidepride: A dopamine D‐2 receptor antagonist radioligand
Authors: Clanton J. A. , de Paulis T. , Schmidt D. E. , Ansari M. S. , Manning R. G. , Baldwin R. M. , Kessler R. M. 
Published: October 2006

Abstract(S)‐(−)‐N‐[(1‐ethyl‐2‐pyrrolidinyl)methyl]‐5‐[123I]iodo‐2,3‐dimethoxybenzamide (TDP 517) (proposed generic name, [123I]epidepride) is the iodine‐123 substituted analogue of isoremoxipride (FLB 457), both of which are very potent dopamine D‐2 antagonists (epidepride KD 0.024 nM). [123I]Epidepride was radioiodinated in 60–70% radiochemical yields in 35 min from the corresponding 5‐(tributyltin) derivative using Na123I with a specific radioactivity of 3000 Ci/mmol, and oxidized in situ with chloramine‐T. The aryltin precursor was prepared from non‐labelled epidepride by palladium‐catalyzed stannylation using bis(tri‐n‐butyltin) in triethylamine. Alternatively, using no carrier‐added Na125I as the radioisotope, [125I]epidepride at 2000 Ci/mmol specific radioactivity was prepared in 86% radiochemical yield and 99% radiochemical purity after purification by reverse phase HPLC in ethanolic phosphate buffer.
Synthesis of [20,21‐13C2]‐progesterone
Authors: Caballero Gerardo M. , Gros Eduardo G. 
Published: October 2006

AbstractThe synthesis of, [20,21‐13C2]‐progesterone (9) from androst‐4‐ene‐3,17‐dione (1) is described. Labels were introduced by two procedures, namely, condensation of 1 with K13CN and Grignard reaction of nitrile derivative 7 with [13C]‐methylmagnesium iodide. Location of labels was confirmed by 13C‐NMR spectroscopy.
Synthesis of [C6‐CH3‐14C] and [C6‐CH3‐3H3]mitomycin C
Authors: Arai Hitoshi , Kasai Masaji 
Published: October 2006

AbstractA facile synthesis of the title compounds 2 and 3 is described. The key intermediate in the synthesis, 6‐demethyl‐7,7‐(ethylenedioxy)‐6‐(phenylselenenyl)mitosane (4) was synthesized in five steps from mitomycin A. Treatment of 4 with [14C]methyl iodide in the presence of K2CO3 afforded the [14C]‐labelled mitosane (5). The removal of the phenylselenenyl group of 5 and subsequent treatment of the resultant mitosane 7 with ammonia led to the desired [14C]mitomycin C (MMC) (2) with specific activity of 50 mCi/mmol. Similarly, [3H]‐labelled MMC (3) with highly specific activity of 78.4 Ci/mmol was obtained.
Synthesis of multiply deuterium‐labelled prednisone and prednisolone
Authors: Shibasaki Hiromi , Furuta Takashi , Kasuya Yasuji 
Published: October 2006

AbstractWe have synthesised prednisone and prednisolone labelled with four deuterium atoms at chemically stable sites ([1,19,19,19‐2H4]prednisone and [1,19,19,19‐2H4]prednisolone), starting from [1,1,19,19,19‐2H5]cortisone. The isotopic purities were demonstrated to be > 98 atom%. There were no indications of deuterium loss from the C‐19 and C‐1 positions during the synthetic sequence involving an oxidation reaction step using selenium dioxide in tert‐butanol.
Syntheses of 3H‐ and 2H‐labeled (16S)‐15‐deoxy‐16‐hydroxy‐16‐methyl‐5‐thiaprostaglandin E1 methyl esters
Authors: Sugiura Satoshi , Tanaka Toshio , Bannai Kiyoshi , Kurozumi Seizi 
Published: October 2006

AbstractThe syntheses of [7‐2H]‐, [7‐3H]‐, and [2,2,3,3,4,4‐2H6]‐(16S)‐15‐deoxy‐16‐ hydroxy‐16‐methyl‐5‐thiaprostaglandin E1 methyl ester (2, 3, and 4) are described. Both 7‐labeled compounds, 2 and 3, were prepared from the Δ7‐precursor (11) by treatment with in‐situ generated tributyltin deuteride and [3H]hydride, respectively. The hexa‐deuterated compound 4 was prepared starting from tetrahydrofuran‐d8
Synthesis of 14C‐labelled (S)‐(+)‐6‐(2‐chlorophenyl)‐3‐cyclopropanecarbonyl‐8,11‐ dimethyl‐2,3,4,5‐tetrahydro‐8H‐pyrido[4′,3′:4,5]thieno[3,2‐f][1,2,4]triazolo[4,3‐a][1,4]diazepine (14C‐E6123)
Authors: Miyazawa Shuhei , Okano Kazuo , Kusano Kazutomi , Tadano Kyoichi , Tanaka Shigeru , Yuzuriha Teruaki , Machida Yoshimasa , Yamatsu Lsao 
Published: October 2006

Abstract14C‐Labelled (S)‐(+)‐6‐(2‐chlorophenyl)‐3‐cyclopropanecarbonyl‐8,11‐dimethyl‐2,3,4,5‐ tetrahydro‐8H‐pyrido[4′,3′:4,5]thieno[3,2‐f][1,2,4]triazolo[4,3‐a][1,4] diazepine (14C‐E6123), a platelet activating factor receptor antagonist for studying the pharmacokinetic profile of E6123, was synthesized in three steps using [1‐14C] acetyl hydrazine fumarate as the labelled starting material. The final product has high chemical and radiochemical purity with a specific activity of 53.2mCi per mmol (1.97GBq per mmol). The overall radiochemical yield is 6.0%.
Enzymatic synthesis of isotopically labelled pyrimidine deoxyribonucleotides
Authors: Frank‐Kamenetskaya  , Myasoedov N. F. 
Published: October 2006

AbstractAn enzymatic method is described which makes it possible to synthesize labelled pyrimidine deoxyribonucleotides from corresponding labelled ribonucleotides using the RDP‐reductase system of ether‐treated E. coli E125 cells. Ether‐treated cells have been used for the first time for preparative enzymatic synthesis of labelled biologically active compounds.
Synthesis of 1,3,5,5–tetranitrohexahydropyrimidine–2,2,4,4,6,6–d6 (DNNC–d6) and its adiol–d4 precursor using paraformaldehyde–d2 and unlabeled reaction ingredients
Authors: Shackelford Scott A. 
Published: October 2006

AbstractUsing commercially available paraformaldehyde–d2, the subject compounds were synthesized with unlabeled reactants and ordinary solvents. The 2,2–dinitropropane–1,3‐diol–1,1,3,3–d4 (ADIOL–d4) precursor was produced in greater than 99% isotopic purity with aqueous depolymerized paraformaldehyde–d2 and CH3NO2 in alkaline solution followed by oxidative AgNO3/NaNO2 nitration; then, ADIOL–d4 and depolymerized paraformaldehyde–d2 with t‐butylamine in methanol afforded cyclic 1,3–di–t‐butyl–5,5–dinitrohexahydropyrimidine–2,2,4,4,6,6–dδ (DBNP–d6). The 97% isotopically pure DNNC–d6 product resulted in 71% yield from an anhydrous HNO3 nitration of DBNP–d6.
Stereoselective synthesis of stable isotope‐labeled L‐α‐amino acids: Chemomicrobiological synthesis of L‐[β‐13C]‐, L‐[2′‐13C]‐, and L‐[1′15N]tryptophan
Authors: Unkefer Clifford J. , Lodwig Siegfried N. , Silks Louis A. , Hanners John L. , Ehler Deborah S. , Gibson Rowena 
Published: October 2006

AbstractWe have developed a stereospecific chemomicrobiological synthesis of labeled tryptophan. L‐[3‐13C]Serine, [1‐15N]‐ and [2‐13C]indole were used as precursors for the synthesis of L‐[β‐13C]‐, L‐[1′‐15N]‐, and L‐[2′‐13C]tryptophan, respectively. The labeled precursors were incorporated quantitatively into tryptophan using a strain of E. coli engineered to overproduce tryptophan synthase. Labeled indoles were prepared by the base‐promoted cyclization of appropriately labeled N‐formyl‐o‐toluide; serine was prepared biosynthetically as described previously.
Syntheses of [2‐14C] 2,5′‐anhydro‐3′‐azido‐3′‐deoxythymidine and [2‐14C] 2,5′‐anhydro‐3′‐azido‐2′,3′‐dideoxy‐5‐iodouridine: Inhibitors of human immunodeficiency virus (HIV‐1)
Authors: Lin Tai‐Shun , Liu Mao‐Chin , August E. Michael , Birks Evelyn M. , Prusoff William H. 
Published: October 2006

AbstractThe syntheses of [2‐14C] 2,5′‐anhydro‐3′‐azido‐3′‐deoxythymidine and [2‐14C] 2,5′‐anhydro‐3′‐azido‐2′,3′‐dideoxy‐5‐iodouridine in a one pot operation under mild conditions are described.
Use of tritiated methylborane in the synthesis of labelled primary amines
Authors: Burgos Alain , Kamenka Jean‐Marc , Rousseau Bernard 
Published: October 2006

AbstractTritiated methylborane prepared from tritium gas and methaneboronic acid was used to prepare [2‐H3]‐trans‐2‐phenylcyclopentylamine from 1‐phenylcyclopentene with a high specific activity (26Ci/mmol) in 20–40% yield.
Synthesis of [14C]‐ and [3H]‐labelled (+)‐[1R‐[1α,2α(Z),3β,4α]]‐7‐[3‐[(Phenylsulfonyl)AMINO]BICYCLO[2.2.1]HEPT‐2‐YL]‐5‐HEPTENOIC ACID, ((+)‐S‐145) AND ITS CALCIUM SALT (S‐1452)
Authors: Nagasaki T. , Watanabe F. , Katsuyama Y. , Hamada Y. , Ohtani M. , Narisada M. 
Published: October 2006

Abstract(+)‐S‐145 and S‐1452, thromboxane A2 receptor antagonists, were labelled with 3H and 14C for studies on the metabolic fate and characterization of receptor binding. 3H and 14C were incorporated into the benzene ring in the phenysulfonylamide side chain with specific radioactivities of 26.4 Ci/mmol and 8.73 mCi/mmol, respectively. The common key intermediate, amine 12a was synthesized in eight steps from 4a for facile labelling.
Synthesis of a Radiotracer for Studying k‐Subtype Opiate Receptors: N‐[11C‐methyl]‐N‐(trans‐2‐pyrrolidinyl‐cyclohexyl)‐3,4‐dichlorophenylacetamide ([11C](±)U‐50488H)
Authors: Noble Glen D. , Dannals Robert F. , Ravert Hayden T. , Wilson Alan A. , Wagner Henry N. 
Published: October 2006

AbstractThe radiochemical synthesis of a κ‐subtype opiate receptor ligand, [11C](±)U‐50488H, was accomplished either in two steps or by direct methylation with [11C]iodomethane. The radiotracer was purified using reversed phase semipreparative HPLC. The average specific activity was 1830 mCi/μmole (calculated at the end‐of‐synthesis; EOS) for the direct methylation and 2140 mCi/μmole EOS for the two‐step one‐pot synthesis. The average time of synthesis including formulation was approximately 22 minutes for the direct methylation and 27 minutes for the two‐step one‐pot synthesis.
Enzymatic synthesis of isotopically labelled purine deoxyribonucleotides
Authors: Frank‐Kamenetskaya  , Myasoedov N. F. 
Published: October 2006

AbstractAn enzymatic method is described which makes it possible to synthesize labelled purine deoxyribonucleotides from corresponding labelled purine ribonucleotides using the RDP‐reductase system of ether‐treated E. coli E125 cells.
Further investigation on the radiosynthesis of α‐[11C]methyl‐tryptophan
Authors: Suehiro Makiko , Ravert Hayden T. , Wilson Alan A. , Scheffel Ursula , Dannals Robert F. , Wagner Henry N. 
Published: October 2006

AbstractImproved procedures for the radiosynthesis of α‐[11C]methyltryptophan and α‐[11C]methyl‐tryptophan methyl ester were studied. Following α‐deprotonation of tryptophan methyl ester benzaldimine with LDA, 60 – 80% of no carrier added [11C]iodomethane was incorporated in 5 minutes at 27 – 30°C. After HPLC purification, radiochemically pure α‐[11C]methyl‐tryptophan or its methyl ester was produced with minimum chemical contamination from tryptophan. The [11C]methyl‐tryptophan synthesized, however, was found to be a racemate.
Improved synthesis of [11C]methylaminobenzovesamicol
Authors: Keith Mulholland G. , Jung Young‐Woon 
Published: October 2006

AbstractAn efficient two‐step synthesis of the potential cholinergic neuronal mapping tracer [11C]methylaminobenzovesamicol (MABV) is described. A tert‐butoxycarbonyl protecting group was used to activate the aniline nitrogen of aminobenzovesamicol toward [11C]methyl iodide methylation under basic conditions. Following labeling, the protecting group was removed by brief acid treatment and the final product was purified by normal phase HPLC. The decay corrected yields of MABV are in the range of 30‐70 %, based on 11CO2, with a specific activity of 0.5‐1.5 Ci/ μmol and synthesis time of less than 45 minutes. This new route makes clinical scale doses of this interesting compound available for human positron emission tomography studies.
HPLC isotope effects and macrocycles: The case of echinocandin B
Authors: Jones Allen N. , Simpson Robert E. , Jenkins Herbert J. 
Published: October 2006

AbstractEchinocandin B was catalytically reduced with hydrogen, deuterium, or tritium. HPLC analysis of the products showed that the labeled analogs exhibited a significant isotope effect relative to the unlabeled parent, with the elution order tritiated < deuterated < hydrogenated. Mass spectral data and specific activity measurements indicated label incorporation exceeded saturation of the double bonds. Proton nmr of the deuterated compound indicated labeling was confined to the aliphatic side chain. A model compound, anilinosteareamide, prepared from the linoleic precursor by reduction with hydrogen or deuterium, incorporated the label only in the aliphatic chain, and also exhibited an isotope effect. This helped confirm that label incorporation in only the fatty acid portion of tetrahydroechinocandin B was sufficient to cause the observed isotope effect.
Development of a novel radioiodinated glucose derivative with interaction to hexokinase
Authors: Magata Yasuhiro , Saji Hideo , Ohmomo Yoshiro , Tanaka Chiaki , Konishi Junji , Yokoyama Akira 
Published: October 2006

AbstractDevelopment of an 123I‐labeled glucose derivative that interacted with hexokinase was attempted. By introducing a benzene ring into the glucosamine molecule, we were able to secure a radioiodinated compound, N‐iodobenzoyl‐D‐glucosamine (BGA), with enhanced stability. As a result, a non‐competitive inhibitory agent on the hexokinase‐regulated phosphorylation reaction was achieved. The inhibitory action and lipophilic property of this novel compound were closely related to an amide bond in its structural configuration. Moreover, on investigating the biodistribution in mice, although this 125I‐labeled compound did not display any uptake into the brain, it demonstrated rapid clearance from the blood with high systemic stability. From the above findings, it is highly possible to develop a clinically feasible 123I‐labeled radioligand that can monitor the quantitative changes and biodistribution of hexokinase.
Synthesis of [14,15,17,17,18,18‐2H6]‐leukotriene B4
Authors: Tsikas Dimitrios , Fauler Joachim , Frölich Jürgen C. 
Published: October 2006

AbstractIncubation of [14,15,17,17,18,18‐2H6] leukotriene A4 obtained by hydrolysis of chiral [14,15,17,17,18,18‐2H6] leukotriene A4 methylester with human monocytes resulted in the formation of [14,15,17,17,18,18‐2H6] leukotriene B4 (d6‐LTB4) and its trans isomers 6‐trans‐d6‐LTB4 and 12‐epi‐6‐trans‐d6‐LTB4 in high isotopic purity (99.4 % 2H). d6‐LTB4 was separated from its trans‐isomers by reversed‐phase high‐performance liquid chromatography and identified by gas chromatography mass spectrometry. d6‐LTB4 is shown to be a useful internal standard for gas chromatographic mass spectrometric analysis of LTB4 in biological matrix.
Synthesis of a tritium labeled tetrafluoro‐substituted aryl azide photoaffinity labeling agent for chloride channels. Application of [3H]‐sodium borohydride‐cobalt chloride to tritium labeling
Authors: Branchini Bruce R. , Adams Elizabeth W. , Egan Laura A. , Murtiashaw Martha H. 
Published: October 2006

Abstract5‐Nitro‐2‐[N‐3‐(4‐azido‐2,3,5,6‐tetrafluorophenyl)‐propylamino]‐benzoic acid (FAzNPPB), a photoaffinity analog of the potent epithelial chloride channel blocker 5‐nitro‐2‐(3‐phenylpropylamino)‐benzoic acid (NPPB) has been prepared in five steps from commercially available 4‐amino‐2,3,5,6‐tetrafluorobenzonitrile. The main feature of this synthesis was the use of NaBH4‐CoCl2 to convert an aryl‐substituted alkenyl nitrile precursor to the corresponding alkyl amine. The feasibility of this approach and the stoichiometry were developed by model work with cinnamonitrile. Using sodium borotritide‐cobalt chloride, [3H]‐FAzNPPB (specific activity 13.9 mCi/mmol, radiochemical purity >99%) was prepared in three steps from (E)‐4‐amino‐2,3,5,6‐tetrafluorocinnamonitrile.
An efficient method for following the enzymic reactions involved in camphor biosynthesis in cinnamomum camphora by use of GC‐MS and regiospecifically deuteriated substrate
Authors: Ohta Shinji , Yamamitsu Tohru , Suga Takayuki 
Published: October 2006

AbstractAn efficient method has been developed to follow the enzymic reactions involved in the biosynthesis of camphor in Cinnamomum camphora (camphor tree) by use of [5,5‐2H2]geranyl diphosphate as a substrate and GC‐MS with selected ion monitoring. Borneol and camphor biosynthesized in the enzymic reactions gave a base peak due to the deuterium‐containing ion in its EI mass spectrum. It is possible to detect 1.5 ng of the biosynthesized borneol and camphor per injection into the GC‐MS. This method enabled us to differentiate easily the biosynthesized camphor from the endogenous camphor and it is a facile and sensitive technique to determine the amount of the biosynthesized camphor.
Synthesis of D‐(‐)‐[1,7‐13C2]shikimic acid
Authors: Cho Hyeongjin , Heide Lutz , Floss Heinz G. 
Published: October 2006

AbstractThe chemical synthesis of 99% enriched D(‐)‐[1,7‐13C2]shikimic acid from [1,2‐13C2]acetate in 25% overall yield is described. A two‐carbon phosphonate synthon was prepared from [1,2‐13C2]acetate and used in the shikimate synthesis of Fleet and coworkers.
Synthesis of tritiated tripeptides and their very simple purification procedures
Authors: Angelini G. , Sparapani C. , Margonelli A. 
Published: October 2006

AbstractThe complete reaction pathway (five steps) for the syntheses of tritiated [CBZ‐Pro‐*Leu‐TrpOH] 7 (POL‐443) and [Pyr‐*Leu‐TrpOMe] 5 (POL‐509) starting from tritiated *Leu‐[3, 4, 5‐3H(N)] is described. The products 5 and 7 are obtained with high level of chemical and radiochemical purity and in good total yield (70% for 5 and 60% for 7) (1). The use of the “Solid Phase Extraction” procedure made the purification and recovery steps very simple and effective with no isotopic exchange.
Solid‐phase catalytic isotope exchange of alkylxanthines with gaseous tritium
Authors: Kaminski Ju. L. , Akulov G. P. , Patokina N. A. , Rosenberg S. G. 
Published: October 2006

AbstractThe results of the synthesis of 11 different tritiated alkylxanthines by solid‐phase catalytic isotope exchange are described. 3H‐NMR analysis of the labelled compounds shows that in contrast to liquid‐phase isotope exchange the tritium label is incorporated not only in the C‐8 (H) position, but also in the alkyl groups. The fraction of radioactivity in an alkyl group depends on the nature and position of this group.
Synthesis of carbon‐14 and tritium analogues of the phospholipid antitumor agent SDZ 62‐834 zi
Authors: Kinder Frederick R. , Tang Yui S. , Sunay Ustun B. 
Published: October 2006

Abstract2‐[[Hydroxy[[tetrahydro‐2‐[(octadecyloxy)methyl]‐2‐furanyl)]methoxy]phosphinyl]oxy]‐N,N,N‐trimethylethanaminium hydroxide inner salt (SDZ 62‐834 zi) was synthesized with carbon‐14 at the furn‐2 position from dimethyl malonate‐[14C]. In addition, SDZ 62‐834 zi was also synthesized with tritium at the furan 3 and 4 positions by catalytic tritiation of 2,5‐dihydro‐2,2‐furandimethanol.
The enantiospecific synthesis of [5‐2H]‐epi‐shikimic acid and of (6R) [6‐2H]‐, (6S) [6‐2H]‐ and [6‐2H2] shikimic acid
Authors: Zamir Lolita O. , Nguyen Cong‐Danh , Li Shu Wen , Nikolakakis Anastasia , Sauriol Françoise 
Published: October 2006

AbstractThe enantioselective synthesis of [5‐2H]‐5‐epi‐shikimic acid starting from commercially available L‐shikimic acid has been accomplished in this work. The introduction of the stable isotope was facilitated by an enzymic reduction of a ketone. An interesting stereospecific enolisation was also observed during this reaction resulting in partial deuteration of the 6‐equatorial position. In addition, the enantioselective syntheses of methyl (6R) [6‐2H]‐, and (6S) [6‐2H] shikimate are described. The procedure is an adaptation of a reported(1) enantiospecific synthesis of shikimic acid, with the inclusion of an enzymic reduction step.
Synthesis of 2‐deoxy‐2‐[18F]‐fluoro‐β‐mannosyl [18F]‐fluoride as a potential imaging probe for Glycosidases
Authors: McCarter John D. , Adam Michael J. , Withers Stephen G. 
Published: October 2006

AbstractThe mechanisms‐based glycosidase inhibitor 2‐deoxy‐2‐[18F]‐fluoro‐β‐mannosyl [18F]‐fluoride was synthesized and its covalent binding to Agrobacterium β‐glucosidase was demonstrated in vitro.
Synthesis of carbon‐14 labelled xenalipin ‐ a potential hypolipidemic agent
Authors: Hill John A. , Eaddy John F. 
Published: October 2006

AbstractXenalipin 1 (4′‐trifluoromethyl‐2‐biphenylcarboxylic acid) was synthesized in the [14C]‐labelled form with specific activity 21.0 mCi/mmol suitable for metabolism and distribution studies in animals. The synthetic sequence involved conversion of [14C]‐ benzoic acid to the 4,4‐dimethyl‐2‐oxazoline derivative, formation of an organozinc compound, palladium‐catalyzed coupling of the arylzinc‐oxazoline with 4‐trifluoromethyliodobenzene, and acid hydrolysis. The radiochemical purity was 99.4%.
Preparation of mono‐15N‐cyanogen and mono‐13C‐cyanogen
Authors: Wilmes Rolf , Winnewisser Manfred 
Published: October 2006

AbstractThe preparation of the unsymmetrically isotope‐labelled title compounds was achieved in pure form for the first time. While mono‐15N‐cyanogen is available in a two‐step‐synthesis, the preparation of mono‐13C‐cyanogen requires five steps, the last step in both cases being the dehydration of mono‐15N‐e.g. mono‐13C‐oxamide with phosphorus pentoxide.
Synthesis of the rice herbicide HW‐52 [dichlorophenyl ring 14C(U)]
Authors: Kimura Ikuo , Yokoyama Norimasa , Kasahara Kaoru , Ueda Takao , Atsumi Kazunori , Filer Crist , Wright Christopher 
Published: October 2006

Abstract14C‐Labeled 2′,3′‐dichloro‐4‐(ethoxymethoxy) benzanilide (HW‐52) (10) was synthesized in a total of 9 steps from 1, 3‐dinitrobenzene [14C(U)]. The key intermediate 2,3‐dichloroaniline [14C(U)] (7) was prepared from the starting material by a series of aromatic substitutions and functional group manipulations. Conversion to the final product was achieved in high yield by coupling and further functional group manipulations. The overall radiochemical yield was 1.88% and radiochemical purity of the product was greater than 98.8%.
The synthesis of N‐[4‐dimethylamino‐1‐butyl(1‐13C)‐N‐nitrosobenzamide], an inhibitor of tryspin; Cyanide does not exchange with acetonitrile
Authors: White Emil H. , Chen Yulong 
Published: October 2006

AbstractThe synthesis of N‐[4‐dimethylamino‐1‐butyl(1‐13C)‐N‐nitrosobenzamide], a powerful active‐site‐directed inhibitor of trypsin, is reported. An efficient use of 13C‐cyanide ion was achieved in the reaction with 1‐chloro‐3‐dimethylaminopropane, the first step of the synthesis. Acetonitrile was used as a co‐solvent with water in that step; no evidence was found for cyanide ion exchange with acetonitrile. The earlier report of such an exchange appears to be in error; the formation of hydrocyanic acid under the reaction conditions can account for the observations.