bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis of deuterium‐labeled N‐nitrosodiethanolamine and N‐nitroso‐2‐hydroxymorpholine
Authors: Loeppky Richard N. , Xiong Heping 
Published: October 2006

AbstractTwo deuterated derivatives of N‐nitrosodiethanolamine and two deuterated derivatives of N‐Nitroso‐2‐hydroxymorpholine were prepared. 1,1,1′,1′‐2H4‐N‐Nitrosodiethanolamine 1a was prepared in 99% isotopic purity by simple base catalyzed H‐D exchange. 2,2,2′,2′‐2H4‐N‐Nitrosodiethanolamine 1b was synthesized in 98% isotopic purity by the LiAlD4 reduction of dimethyl iminodiethanoate, followed by acid catalyzed nitrosation. 5,5‐2H2‐N‐Nitroso‐2‐hydroxymorpholine 2a was prepared in 99% isotopic purity through a series of steps involving 1) the selective base catalyzed H‐D exchange of the CH2 adjacent to the ester function of 2,2‐diethoxyethylcarboethoxymethylnitrosamine, 2) its reduction with diisobutylaluminum hydride at −8°C followed by 3) acid catalyzed hydrolysis of the acetal and cyclization to the hemiacetal. 2‐2H‐N‐Nitroso‐2‐hydroxymorpholine 2b (98% isotopic purity) was prepared through the LiAlD4 reduction of 2‐hydroxyethylcorboethoxymethylnitrosamine at −78°C.
The preparation of high purity H235S
Authors: Collins C. D. , Bell J. N. B. 
Published: October 2006

AbstractH2 35S was synthesised by the reaction of H2 with elementary [35S] sulphur at 600°C with 100 mg of pumice added as a catalyst. The resulting gas was purified by placing the preparation vessel in a pack of ice. A yield of 46% was produced.
Synthesis of an 125I analog of MK‐0591 and characterization of a 5‐lipoxygenase activating protein binding assay
Authors: Eggler J. F. , Cheng J. B. , Cooper K. , Hanak L. M. , Pillar J. S. , Zdankiewicz M. 
Published: October 2006

AbstractThe 125I analog of MK‐0591, 1, has been prepared for use as a radioligand for developing a 5‐lipoxygenase activating protein (FLAP) binding assay. The radiosynthesis involves a two step oxidative iododestannylation‐saponification procedure. A FLAP binding assay has been developed in human neutrophil membranes. The binding of 1 to human neutrophil FLAP is rapid, reversible, of high affinity, saturable and selective for FLAP inhibitors.
Synthesis of (+)‐(3R)‐3‐(4‐fluorophenylsulfonamido)‐1,2,3,4‐tetrahydro‐9‐[5,6,7,8,12,13‐U‐14C]carbazolepropanoic acid, [14C]BAY u 3405
Authors: Radtke Martin , Boberg Michael , Pleiss Ulrich , Rosentreter Ulrich 
Published: October 2006

AbstractThe title compound [14C]BAY u 3405 (1) was synthesized as part of 8‐step sequence. Starting from [U‐14C]aniline hydrogensulfate the final product 1 was obtained with a specific activity of 741 MBq/mmol (20 mCi/mmol) and a radiochemical purity of > 98% in an overall yield of 6 and 10% depending on the method.
Bromination and subsequent catalytic tritiation of thienylalanine and 4‐methyltyrosine residues in the bradykinin analog RMP‐7
Authors: Akiyama Alan , Musso Gary F. , Smart Janet L. , Lang Christopher , Straub Julie Ann 
Published: October 2006

AbstractA two step strategy was devised for the synthesis of 3H‐RMP‐7 for use in pharmacokinetic studies. First, RMP‐7 was brominated predominantly on the thiophene ring of thienylalanine using Br2 in AcOH. Then, reductive tritiation of the brominated RMP‐7 using 3H2 and Pd/C yielded 3H‐RMP‐7 (specific activity 1 Ci/mmol; 96% radiochemical purity). An HPLC based assay using on‐line radioactivity detection was developed for in vivo pharmacokinetic studies of 3H‐RMP‐7. Rapid clearance from the blood and metabolism of RMP‐7 to des‐Arg1‐RMP‐7 was observed in vivo in rats.
N.C.A. 11C‐labelling of benzenoid compounds in ring positions: Synthesis of nitro‐[1‐11C]benzene and [1‐11C]aniline
Authors: Steinbach J. , Mäding P. , Füchtner F. , Johannsen B. 
Published: October 2006

AbstractThe paper describes the first method for n.c.a 11C‐ring labelling of benzenioid compounds having a reactive group for further derivatization by use of the known principle of synchronous six‐electron cyclization of hexatriene systems into aromatics. Nitro‐[11C]methane (1) prepared from cyclotron‐produced [11C]carbon dioxide reacts in the presence of t‐BuOK with 5‐dimethylaminopenta‐2,4‐dienylidene‐dimethylammonium perchlorate (2) to form 6‐nitro‐1‐dimethylamino‐[6‐11C]hexatriene (3) follow by cyclization/ aromatization into nitro‐[1‐11C]‐benzene (4) at increased temperatures. Starting from 1, nitro‐[1‐11C]benzene of a radiochemical purity of about 92 % and a mean specific radioactivity of 1 Ci/μmol was obtained within 7 min. Related to [11C]CO2, the reproducible radiochemical yield of 4 (decay‐corrected) was 80±5 %. Reduction of 4 by heating the above reaction mixture with aqueous Na2S gave [1‐11C]aniline (5) of aradiochemical purity of about 81 %. The reproducible radiochemical yield of 5 (decay‐corrected) in relation to [11C]CO2 was 65±5 %, the synthesis time from 1 was 18 min.
Synthesis of β‐3H‐mitotane for use in a rapid assay for mitotane metabolism
Authors: Piñeiro‐Sánchez Mayra L. , Vaz Alfin D. N. , Counsell Raymond E. , Ruyan Mohamed , Schteingart David E. , Sinsheimerl Joseph E. 
Published: October 2006

AbstractA 3H+‐release method has been developed for the assay of β‐hydroxylation of the adrenolytic drug mitotane. β‐3H‐mitotane was synthesized by the reduction of 1‐(2‐chlorophenyl)‐1‐(4‐chlorophenyl)‐2,2,2‐trichloroethane by an aluminium‐Hg2Cl2 couple in the presence of 3H2O. For β‐hydroxylation of mitotane, the 3H+‐release assay is more efficient and sensitive than a method utilizing 14C‐mitotane and chromatographic separation of metabolites by HPLC. The 3H+‐release assay has been used to evaluate the ability of adrenal tumors to metabolize mitotane via the β‐ hydroxylation route.
Strategies for labelling branched polypeptides with a poly(L‐lysine) backbone with radioiodines (123I, 125I, 131I) and radiometals (111In, 51Cr) for biodistribution studies and radiopharmaceutical development
Authors: Pimm Malcolm V. , Gribben Sandra J. , Mezö Gábor , Hudecz Ferenc 
Published: October 2006

AbstractMethods have been developed for radiolabelling synthetic branched polypeptides, these being based on a poly(L‐lysine) backbone with short side chains of three DL‐alanine residues and one other amino acid at the end of the branches (MW ∼45‐100 kDa). Labelling has been carried out with gamma emitting radionuclides suitable for use in biodistribution studies or for gamma scintigraphy. Labelling with 125I was achieved by reaction of the polypeptides' terminal amino groups with pre‐iodinated Bolton and Hunter Reagent (N‐Succinimidyl 3‐(4‐hydroxy‐5‐[125I]iodophenyl)propionate). Alternatively, polypeptides were reacted with non‐labelled Bolton and Hunter reagent, which could subsequently be iodinated with 123I, 125I or 131I by oxidative incorporation from [123I]Nal, [125I]Nal, or [123I]Nal. For labelling with radiometals, the polypeptides' terminal amino groups were reacted with diethylenetriaminepentaacetic acid (DTPA) anhydride, and the conjugated DTPA subsequently labelled with 111In or 51Cr by chelation. An amphoteric polypeptide, having terminal glutamic acid residues on its side chains (EAK), and a polycationic polypeptide, with terminal D‐lysine (D‐KAK) were labelled in these ways. In addition EAK previously conjugated to the cis‐aconityl derivative of daunomycin (EAK‐cAD) was similarly labelled. Gel permeation chromatography on Sephacryl S‐300, which was possible with the amphoteric EAK, showed virtually identical elution profiles with 123I, 125I 131I, 111In and 51Cr labelled EAK and its cAD conjugate. Biodistribution studies in mice showed prolonged blood survival of the radionuclide of 125I, 111In or 51Cr labelled EAK and EAK‐cAD. There were, however, differences in organ levels of the radionuclides. Generally kidney, spleen and liver levels of radiometals were higher than those of radioiodine, while levels in the gastrointestinal tract were higher with radioiodine. D‐KAK labelled with any of the three radionuclides was cleared rapidly from the blood, high levels of all tracers being found in spleen, liver, kidney and lung.
Synthesis of 14C‐labelled Cefluprenam (E1077), a novel parenteral cephalosporin antibiotic
Authors: Sato Nobuaki , Kai Yasunobu , Shemilt G. I. , Chiku Shigeru 
Published: October 2006

AbstractCefluprenam (E1077) is a new parenteral cephalosporin with a well‐balanced antibacterial spectrum and potent antibacterial activity. It was synthesized labelled in the side chain at the 3‐position of the cephem with carbon‐14, starting from potassium [14C]cyanide, according to the method illustrated in Schemes 1,2. [14C]Cefluprenam having a specific activity of 3.9 MBq/mg, was obtained in 28.6 % overall radiochemical yield, with a radiochemical purity of more than 97.3 %.
New [99mTc]‐cytectrene amine compounds as specific brain imaging agents
Authors: Kuntschke Dirk , Wenzel Martin , Schulze Paul 
Published: October 2006

AbstractLipophilic tertiary amines attached to cyclopentadienyl technetium‐99m tricarbonyl (cytectrene) have been prepared with high radiochemical yield and purity. Biodistribution studies in mice showed that [99mTc]‐cytectrenes, containing in their structure an N‐methylpiperidine, were accumulated in the brain up to 2.8 % of injected dose with high brain‐to‐blood ratios at 15 min p.i.1. They therefore indicate some potential as brain imaging agents.It has to be pointed out that the N‐methylpiperidine ester showed similar biological behaviour as the keto derivative. This indicates that the conversion to polar metabolite(s) via hydrolysis of the ester group ‐ as described for [99mTc]‐ECD ‐ is not essential for brain retention.
Synthesis of N‐[4‐[2‐(2,4‐dimethylphenoxy)phenyl]‐2‐thiazolyl]‐hexahydro‐2‐pyrimidinimine, [14C]BAY w 6341
Authors: Pleiss Ulrich , Conrad Michael , Baasner Bernd 
Published: October 2006

AbstractThe title compound [14C]BAY w 6341 was synthesized as part of a 4‐step sequence. Starting from diethyl [2‐14C]malonate the final product (8) was obtained with a specific activity of 1.2 GBq/mmol (32.9 mCi/mmol) and a radiochemical purity of > 99 % in an overall yield of 19 %.
Synthesis of tritium labelled 2‐vinyl dihydrosphingosine‐1‐phosphate
Authors: Boumendjel Ahcene , Miller Stephen P. F. 
Published: October 2006

AbstractThe synthesis of [1,1,3‐3H]‐2‐vinyl dihydrosphingosine‐1‐phosphate is described. The key step in this synthesis is the reduction of methyl 2‐trifluoro acetamido‐2‐vinyl nonadecanoate‐3‐one by means of 3H‐calcium diborohydride. This compound was synthesized to determine whether 2‐vinyl dihydrosphingosine‐1‐phosphate inhibits the PLP‐dependent sphingosine‐1‐phosphate lyase irreversibly via covalent modification.
Synthesis of [u‐13C,15N]‐cysteine hydrochloride: An important tool for heteronuclear, multi‐dimensional NMR studies of proteins
Authors: Panigot Michael J. , Fesik Stephen W. , Curley Robert W. 
Published: October 2006

AbstractProtein structure determination by modern NMR techniques is greatly facilitated using 15N‐ and 13C‐labeled proteins. Labeling of proteins that are overexpressed in mammalian cells is a difficult task that requires a growth medium consisting of algal hydrolysates supplemented with labeled amino acids. Although most of the amino acids can be obtained to prepare an isotopically labeled growth medium for mammalian cells,[U‐13C,15N]‐cysteine is not available, hampering the backbone and cysteine side‐chain assignments and structure determination in the vicinity of the cysteine residues. A synthesis of D,L‐[U‐13C,15N]‐cysteine hydrochloride in good overall yield is described which makes use of readily available 15N‐ and 13C‐labeled starting materials and will facilitate heteronuclear multidimensional NMR studies of proteins that are overexpressed in mammalian cells.
Synthesis of paclitaxel‐C3′‐14C
Authors: Walker Donald G. , Standridge Robert T. , Swigor John E. 
Published: October 2006

AbstractReductive cleavage of the C13 side chain of paclitaxel (3) followed by regioselective silylation gave 7‐triethylsilylbaccatin III (6). Successive reaction of L‐threonine methyl ester hydrochloride (7) with tertbutoxydiphenylchlorosilane, benzaldehyde‐C7‐14C and acetoxyacetyl chloride/ triethylamine gave a 92:8 ratio (NMR) of azetidinones 10:11 in 57% yield from 7. Removal of the chiral auxiliary led to 16, which after 3‐O‐triethylsilylation and N‐benzoylation provided (3R,4S)‐cis‐1‐benzoyl‐3‐O‐(triethylsilyl)‐4‐phenylazetidin‐2‐one‐C4‐14C (18). Coupling of 18 and 6 followed by deprotection gave 1.12 g of paclitaxel‐C3′‐14C (2) having a specific activity of 16.4 mCi/mmol and a radiochemical purity of 96%.
Synthesis of [14C2] SDZ FOX 988, a hypoglycemic agent
Authors: Sunay Ustun B. , Talbot Kenrick , Prasad Kapa , Lee George , Jones Lawrence 
Published: October 2006

Abstract4‐[2,2‐Dimethyl‐1‐oxopropyl‐1‐[14C]‐4‐[2,2‐dimethyl‐1‐oxopropyl‐ 1‐[14C]‐phenyl(methoxyimino)‐benzoic acid, methyl ester, [14C2] SDZ FOX 988, doubly labelled in the two keto carbons, was prepared from 4‐bromotoluene in four steps. The final condensation featured a novel method for preparation of N‐oxyimidic acid derivatives.
A new practical method for the preparation of [3H6]‐leukotrienes C4 and D4
Authors: Belley Michel L. , Gareau Yves , Zamboni Robert J. , Ahern David G. , Hong Yang 
Published: October 2006

AbstractA new method for the synthesis of highly deuterated or tritiated leukotrienes was developed. The higher reactivity of a terminal alkene compared to a 1,2‐disubstituted one permitted the selective deuteration or tritiation of the diyne 14,15,19,19,20,20‐hexadehydro LTC4 triester 1. After hydrolysis, LTC4 was obtained in 36% overall yield. An average of seven deuterium or tritium atoms was incorporated and the specific activity of the tritiated LTC4 was greater than 180 Ci/mmol. 1 was obtained from the addition of glutathione to 14,15,19,19,20,20‐hexadehydro LTA4 ethyl ester which was the product of a Wittig reaction between (3,8‐nonanediyn‐1‐yl)triphenylphosphonium iodide and 5(S), 6(S), 7(E), 9(E) ethyl 5,6‐epoxy‐11‐oxo‐7,9‐undecadienoate.
Synthesis of tritiated 1α,25‐dihydroxy‐22‐oxavitamin D3
Authors: Watanabe Hiroyoshi , Akiyama Masashi , Kawanishi Takehiko , Kubodera Noboru 
Published: October 2006

AbstractSynthesis of two tritiated 1α,25‐dihydroxy‐22‐oxavitamin D3 (OCT), [26‐3H3]OCT (3) and [2β‐3H]OCT (4), is described. [26‐3H3]OCT (3) was prepared by tritiation at the side chain with tritiated methylmagnesium iodide and [2β‐3H]OCT (4) was labeled at the A‐ring by tritiation with sodium borotritiide.
Synthesis of 1,1′‐carbonyldimidazole‐1‐14C and its use in preparing a methoxy(polyethylene)glycol semicarbazide linker
Authors: Walker Donald G. , Leister William H. , Weaner Larry E. 
Published: October 2006

AbstractReaction of N‐(trimethylsilyl)imidazole (2) with phosgene‐14C in toluene afforded 92 w/w % pure (1H NMR) 1,1′‐carbonyldimidazole‐1‐14C (3) in near quantitative yield. Activation of MPEG‐amine 4 by reaction with 3 in dichloromethane afforded intermediate 5 in situ. Further reaction with hydrazine in toluene at 50°C and reprecipitation from 2‐propanol afforded crude 1 (81%). A two‐step chromatographic purification of this material followed by reprecipitation from 2‐propanol gave MPEG‐semicarbazide linker1. This material had a chemical purity estimated at 98%, a radiochemical purity of 95%, a specific activity of 7.7 μCi/mg (37.6 mCi/mmol) and a number‐average molecular weight of 4885 (1H NMR).
A one‐step synthesis of [3‐2H]oxazepam
Authors: Yang Shen K. , Bao Ziping , Shou Magang 
Published: October 2006

AbstractThe proton at 3‐position of oxazepam (7‐chloro‐1,3‐dihydro‐3‐hydroxy‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one) undergoes a deuterium exchange in deuterated alkaline methanol. A base‐catalyzed keto‐enol tautomerism is proposed to be responsible for the observed deuterium exchange. This simple method is a considerable improvement of the multi‐step synthetic procedure reported in the literature.
Synthesis of a tritium labeled rat enterostatin, Val‐[3,4‐3H‐Pro]‐Gly‐[3,4‐3H‐Pro]‐Arg‐Oh
Authors: Kozlowski Edward S. , Dischino Douglas D. , Johnson Graham 
Published: October 2006

AbstractA tritium labeled rat Enterostatin, Val‐[3,4‐3H‐Pro]‐Gly‐[3,4‐3H‐Pro]‐Arg‐OH, was prepared by the catalytic tritiation of the didehydroproline analog of rat Enterostatin, Val‐[3,4‐dehydroPro]‐Gly‐[3,4‐dehydroPro]‐Arg‐OH, over Pd/C in methanol. The product had a specific activity of 59.2 Ci/mmol and a radiochemical purity of greater than 99%.
Pesticides labelled with 14C I. Synthesis of [6‐14C]hexazinone
Authors: Koltai Ernǒ , Rutkai György , Kling Ferenc 
Published: October 2006

AbstractHexazinone ‐ a s‐triazine type contact herbicide ‐ was labelled with 14C for the investigation of metabolic pathways. A convenient synthesis was elaborated for labelling of the carbon atom in the 6 position of the triazine ring. The molar activity of Hexazinone was 797.0 MBq/mmole (21.54 mCi/mmole).
Synthesis of deuterium‐labeled acrivastine and an acrivastine metabolite
Authors: Thompson J. B. , Blake K. W. , McNutt R. W. 
Published: October 2006

AbstractThe antihistamine acrivastine and a metabolite dihydroacrivastine were prepared as their [2H7]‐congeners from [2H8]‐tolualdehyde for use as internal standards in gas chromatography/mass spectroscopy of biological samples.
Preparation of [2′,3′,5′,6′‐2H4]pteroylglutamic acid
Authors: Dueker Stephen R. , Jones A. Daniel , Smith Gary M. , Clifford Andrew J. 
Published: October 2006

AbstractFolic acid plays a key role in nucleic acid biosynthesis, essential for normal cell proliferation and function. Localized folate deficiencies may be related to changes in cytology associated with cancer development; analogs of folic acid, such as methotrexate, are potent chemotherapeutic agents and are widely used either alone or in combination therapy for many types of cancer. In this report we describe the synthesis of a tetra‐deuterated folic acid from perdeuterated toluene. The primary intermediate, N‐(4‐amino [2,3,5,6‐2H4]benzoyl)‐L‐glutamic acid diethyl ester was coupled to N(2′)‐acetyl‐6‐formylpterin to create [2′,3′,5′,6′‐2H4]folic acid. A similar scheme can be used for the preparation of [1′,2′,3′,4′,5′,6′‐13C6]folic acid from [13C6] ring labeled toluene.
Radiolysis of radioimmunoconjugates. Reduction in antigen‐binding ability by α‐particle radiation
Authors: Larsen Roy H. , Bruland Øyvind S. 
Published: October 2006

AbstractThe potential of delivering a high and localized radiation dose using α‐particle‐emitting radioimmunoconjugates (RIC's) is investigated as treatment for some types of cancer. High specific activity of the RIC may for some uses be desirable, allowing enrichment of the radionuclide on membrane antigens on target cells. Radiation exposure during the radiolabelling procedures may, however, reduce the antigen binding ability of RIC's of high specific activity. The influence of α‐particle dose on the cell binding fraction was therefore investigated for two monoclonal antibodies, i.e., TP‐1 F(ab')2 and TP‐3 IgG. Samples of 125I‐labelled MoAb were added different amounts of [211At]astatide to give accumulated doses ranging from 50 to 50,000 Gy. After the 211At had decayed 15 half‐lives, the cell binding fractions were measured. The results show that [211At] astatide activities up to 25 kBq/μl, corresponding to an accumulated α‐particle radiation dose of approximately 1,000 Gy, could be tolerated without significantly reducing the cell binding fraction, whereas higher doses gradually reduced the immunoreactivity. Although there may be differences in dose sensitivity of different radioimmunoconjugate due to differences in radionuclide conjugation methods, size of the antibody and structure of the antigen binding portion, the results presented here indicate that it is possible to produce radioimmunoconjugates of high specific activity with currently used methods of preparation. The potential problem of radiolysis should, however, be taken into consideration when planning procedures for preparation and use of α‐particle‐emitting radioimmunoconjugates.
Synthesis of (2E,6E)‐[10‐3H]farnesol and (2E6E)‐[10‐3H]farnesal for insect dehydrogenase studies
Authors: Sen Stephanie E. , Garvin Gail M. 
Published: October 2006

Abstract[10‐3H]Farnesol ((2E,6E)‐3,7,11‐trimethyl‐2,6,10‐dodecatrien‐1‐ol) and [10‐3H]farnesal ((2E,6E)‐3,7,11‐trimethyl‐2,6,10‐dodecatrien‐1‐al) were synthesized by sequential reduction and oxidation of the corresponding tert‐butyldiphenylsilyl protected 11,12,13‐trisnoraldehyde, followed by Wittig homologation using isopropyltriphenylphosphorane. Direct reduction of the C‐12 allylic bromide or allylic chloride proved to be an nonviable method, resulting in either multiple decomposition products or significant double bond transposition. Oxidation of the [10‐3H]labelled trisnoralcohol with pyridinium chlorochromate resulted in essentially complete retention of the radiolabel as was established for the corresponding deuterated material. [3H]labelled farnesol and farnesal were obtained in 78% and 74% yields, respectively, from the trisnoraldehyde. These materials were used as radiotracers for examining the enzymatic activity of insect farnesol and farnesal dehydrogenase, key enzymes in the biosynthesis of juvenile hormone.
The synthesis of [U‐14C phenyl] LS 840606, an agricultural fungicide
Authors: Madegard G. , Mestre P. , Raimond P. , Noël J‐P. 
Published: October 2006

Abstract2,2′4′‐Trichloro‐[ring U‐14C]acetophenone 3 was the key intermediate of this synthesis patterned after the industrial route. An unexpected poor yield was observed during the preparation of 3 by the Friedel‐Crafts reaction of chloroacetyl chloride with 1,3‐dichloro‐[U‐14C]benzene 10, possibly the result of an isotope effect although this poor yield might be explained by other factors.Two routes were checked for the preparation of 1,3‐dichloro‐[U‐14C]benzene 10. The action of CCL4 with 1,3‐dinitro‐[U‐14C]benzene at 280°C was entailed with explosions. A safer route started from [U‐14C]aniline via 2,4‐dichloro‐[ring U‐14C]acetanilide.Friedel‐Crafts reaction of 10 with acetyl chloride gave rise in 52% yield to 2′,4′‐dichloro‐[ring U‐14C]acetophenone 16 which was brominated to 2‐bromo‐2′,4′‐dichloro‐[ring U‐14C]acetophenone 17;17 was condensed with 2,2‐(ethylenedioxy)ethylmagnesium bromide to compound 18; 18 was condensed with 1,2,4‐triazole to 5 then successively treated with HCl:water:dioxane and 2,2,2‐trifluoroethanol/HCl. Separation of the two diastereomers by medium pressure liquid chromatography. 7% overall radioactive yield from [U‐14C]aniline. Radiochemical purity 99%.
The synthesis and purification of 2, 6‐di‐tert‐buytl‐p‐cresol‐−14C6
Authors: Shipp B. D. , Data J. B. , Christian J. E. 
Published: October 2006

Abstract2, 6‐Di‐tert‐butyl‐p‐cresol‐14C6 was synthesised by reacoting p‐cresol‐14C6 with isobutylene using concetentrated sulfurica acid as catalyst.Purification of the Labelled butylated p‐cresol involved very careful recrystalliation of this product from absolute alcohol.Proof of radiochemical purity was determined using thin layer chromatography and autoradiography. Internal liquid acintillation counting techniques were used to determine the apeacific activity of the compound.
Die synthese von mit 14C‐isotop markierten aryl‐isothiocyanten
Authors: Zòlyomi G. , Toldy L. , Bánfi D. 
Published: October 2006

AbstractDie thermische Zersetung von Aryl‐thioharmstoffe, zwecks Darstellung der mit 14C‐Isotop markierten Aryl‐isothiocyanate wurde untersucht. Aus 2, 6‐Dichlorphenyl‐, bzw. 2, 6‐Dimethyl‐phenyl‐isothiocyanate ausgehend wurden substituierte, mit radioaktivem Kohlenstoff markierte Thiazolidin‐Derivate synthetisiert.
Preparation of labeled aflatoxin B1 from acetate‐1, 2‐14C
Authors: Mabee M. S. , Chipley J. R. , Applegate K. L. 
Published: October 2006

AbstractAflatoxin B1‐14C was produced by resting cell cultures of Aspergillus flavus (NRRL 3145) from a sodium acetate ‐ 1, 2‐14C precursor. A specific activity of 455 uCi/uM was determined for the purified aflatoxin B1‐14C.