摘要:

AbstractWe have synthesized the fluorine‐18 labeled derivative ofN‐tert‐butyl‐α‐phenylnitrone (PBN), a free radical spin trapping agent widely used with electron spin resonance (ESR).N‐tert‐Butyl‐α‐(4‐[18F]fluorophenyl)‐nitrone ([18F]FPBN) could be prepared with low radiochemical yield (3% decay corrected) by the direct aromatic nucleophilic substitution ofN‐tert‐butyl‐α‐(4‐nitrophenyl)nitrone with [18F]fluoride. An alternate two step synthesis route consisted of the nucleophilic [18F]fluoride substitution of 4‐N,N,N‐trimethylammoniumbenzaldehyde triflate to yield 4‐[18F]fluorobenzaldehyde, which was distilled into a vial containingN‐tert‐butyl‐hydroxylamine in 2N NaOH. 4‐[18F]Fluorobenzaldehyde readily reacted with the hydroxylamine to form [18F]FPBN. [18F]FPBN was obtained in overall decay corrected yields of 24% in a total synthesis time<45 min. and was suitable for furthe

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360202

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAn improved synthesis of the tritium labelled form of the new pharmacon DIENOGEST is described. The [14α,15α‐3‐H]DIENOGEST was obtained with a specific activity of 51 Ci/mmol and a radiochemical purit

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360203

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA3H+‐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‐Hg2Cl2couple in the presence of3H2O. For β‐hydroxylation of mitotane, the3H+‐release assay is more efficient and sensitive than a method utilizing14C‐mitotane and chromatographic separation of metabolites by HPLC. The3H+‐release assay has been used to evaluate the ability of adrenal tumors to metabolize mitot

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360204

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe synthesis of a new radioligand, which binds with high selectivity and affinity (KD= 7.4 nM) to the GABA‐B receptor, is described. A Wittig‐Horner approach was employed to prepare an unsaturated protected intermediate (6), suitable for tritiation and deprotect

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360205

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA delta opioid receptor antagonist, N1′‐methylnaltrindole (MeNTI), has been labeled with carbon‐11. The precursor for radiolabeling was prepared in 71% yield by benzylation of the phenolic moiety of naltrindole. Alkylation of the indole nitrogen using [11C]iodomethane and aqueous tetra(n‐butyl)ammonium hydroxide at 80 °C in dimethylformamide followed by hydrogenolysis (H2, 10% Pd‐C) of the benzyl protecting group gave [11C]MeNTI. The average (n = 10) time for radiosynthesis, HPLC purification and formulation was 24 min from end‐of‐bombardment. [11C]MeNTI of high radiochemical purity was obtained at end‐of‐synthesis with an average specific activity of 2050 mCi/μmol and radiochemical yield, based on [11C

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360206

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

Abstract2‐Chloro‐N‐(ethoxymethyl)‐N‐(2‐ethyl‐6‐methylphenyl)acetamide (the chloroacetanilide herbicide acetochlor) and 3‐(dichloroacetyl)‐ 2,2,5‐trimethyl‐1,3‐oxazolidine (the dichloroacetamide safener R‐ 29148) are required at high specific activity for studies on their metabolism and mode of action. [phenyl‐4‐3H]Acetochlor was obtained at 22 Ci/mmol in 71% yield by reductive dehalogenation of iodoacetochlor with tritium gas in ethanol in the presence of palladium on carbon and triethylamine. [2,2‐dimethyl‐3H]R‐29148 was prepared at 15 Ci/mmol by treating acetone and 1‐amino‐2‐propanol in pentane with two equivalents of NaOH in tritiated water (i.e. hydroxide ion‐catalyzed enolization of

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360207

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

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 with125I 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 with123I,125I or131I 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 with111In or51Cr 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 thecis‐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 with123I,125I131I,111In and51Cr labelled EAK and its cAD conjugate. Biodistribution studies in mice showed prolonged blood survival of the radionuclide of125I,111In or51Cr 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 foun

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360208

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

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 Schemes1,2.[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 9

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360209

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSolid state catalytic hydrogen isotope exchange has been employed to label hen egg lysozyme with tritium. Optimization of reaction conditions so that amino acids and peptide bonds remained intact led to a tritiated product with 97% of the original enzymatic activity and 94% radiochemical purity. The specific activity when using a T2:H2mixture of 1:1000, was 16 mCi·mmol−1. It is suggested that the currently adopted approach may have wide applications for other proteins able to tolerate lyophilization conditions without loss of activi

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360210

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractHPLC and mass spectrometry can be used to isolate and identify all metabolites of caffeine in plasma of patients. The synthesis of [1,3‐15N2] xanthine and [1,3‐15N2] caffeine are of interest in the elucidation of mass spectrometry fragmentation pathways and the unambiguous determination of metabolites, especially uric acid which exists as a natural constituent of human pla

ISSN:0362-4803    

DOI:10.1002/jlcr.2580360211

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY