Home About us Contact
|
Home About us Contact | ||
|
|
||
Labeling Agent (labeling + agent)
Selected AbstractsRadiosynthesis of 13N-labeled thalidomide using no-carrier-added [13N]NH3JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 2 2010Katsushi Kumata Abstract Recent studies revealed that thalidomide (1) has unique and broad pharmacological effects on multi-targets although the application of 1 in therapy is still controversial. In this study, we synthesized nitrogen-13-labeled thalidomide ([13N]1) as a potential positron emission tomography (PET) probe using no-carrier-added [13N]NH3 as a labeling agent. By use of an automated system, [13N]1 was prepared by reacting N -phthaloylglutamic anhydride (2) with [13N]NH3, following by cyclization with carbonyldiimidazole in a radiochemical yield of 56±12% (based on [11N]NH3, corrected for decay) and specific activity of 49±24,GBq/µmol at the end of synthesis (EOS). At EOS, 570,780,MBq (n=7) of [13N]1 was obtained at a beam current of 15,µA after 15,min proton bombardment with a synthesis time of 14,min from the end of bombardment. Using a small animal PET scanner, preliminary biodistribution of [13N]1 in mice was examined. Copyright © 2010 John Wiley & Sons, Ltd. [source] Radiosyntheses and reactivities of novel [18F]2-fluoroethyl arylsulfonatesJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 10 2005John L. Musachio Abstract [18F]2-Fluoroethyl tosylate ([18F]FEOX, X=Ts) is widely used for labeling radiotracers for positron emission tomography (PET). Little work has been reported on syntheses of other [18F]2-fluoroethyl arylsulfonates ([18F]FEOX) that bear a less electron-rich aryl group, even though these might offer enhanced reactivities. Thus, a series of novel [18F]FEOX (X=benzenesulfonyl, brosyl, nosyl, 3,4-dibromobenzenesulfonyl) were synthesized and reactivities compared to [18F]FEOTs. Precursors for radiolabeling (bis -ethylene glycol arylsulfonates) and reference FEOX were synthesized (alcohol+arylsulfonyl chloride+KOSiMe3 in THF). Regardless of substitution pattern, [18F]FEOX (110°C, 5 min, acetonitrile) were obtained in similar decay-corrected isolated radiochemical yields (RCY; 47,53%). All [18F]FEOX gave excellent RCYs (64,87%) of the dopamine uptake radioligand, [18F]FECNT (130°C, 10 min, acetonitrile). The 3,4-dibromobenzensulfonate gave the highest RCY of [18F]FECNT (87%) and this HPLC-purified labeling agent was used directly for efficient [18F]FECNT production. When the secondary aniline of an amyloid probe (HM-IMPY) or p -nitrophenol was reacted with [18F]FEOX, RCYs were appreciably higher for brosylate and nosylate than for tosylate, while 3,4-dibromobenzenesulfonate again gave the highest RCY. Owing to the high reactivity of the new [18F]FEOX and their ease of syntheses via stable precursors, such agents (particularly 3,4-dibromobenzenesulfonate) should be considered as alternatives to [18F]FEOTs. Copyright © 2005 John Wiley & Sons, Ltd. [source] A combined loop-SPE method for the automated preparation of [11C]doxepinJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 4 2002R. Iwata Abstract A simple and versatile loop-solid phase extraction (SPE) method was developed for the automated preparation of [11C]doxepin, a histamine H1 receptor antagonist, from [11C]methyl triflate ([11C]MeOTf). This labeling agent was passed through a Teflon or Tefzel loop coated internally with a film of the precursor solution. The reaction products were then flushed from the loop to a short SPE column, where they were concentrated and then injected onto a semi-preparative HPLC column simply by switching an injection valve. By applying this combined loop-SPE technique the whole procedure turned out to be easily automated. The formation of [11C]methylated doxepin ([11C]methyldoxepin) was observed and the ratio of doxepin to methyldoxepin was found to be clearly correlated with the mass ratio of nordoxepin to MeOTf. This observation highlights the importance of [11C]MeOTf specific activity in the [11C]methylation of secondary amines. Using this method, [11C]Doxepin was prepared in over 40% radiochemical yield from high specific activity [11C]MeOTf. Copyright © 2002 John Wiley & Sons, Ltd. [source] DNA Aptamers that Bind to PQQGDH as an Electrochemical Labeling ToolELECTROANALYSIS, Issue 11 2009Yuko Osawa Abstract We screened DNA aptamers that bind to pyrroquinoline quinone glucose dehydrogenase (PQQGDH) for the development of an electrochemical labeling tool. PQQGDH is an excellent enzyme for the signal amplification of biosensors. We focused on DNA aptamers as labeling agents and tried to select those DNA aptamers that bind to PQQGDH without affecting its enzymatic activity. After 7 rounds of screening, one aptamer was obtained: ,PGa4'. It bound to PQQGDH with specificity and showed no effect on the glucose dehydrogenase (GDH) activity. Moreover, beads labeled with PQQGDH via PGa4 generated an electrical current upon glucose addition. Therefore, we believe that the PGa4 aptamer against PQQGDH may become a powerful labeling tool for electrochemical biosensors. [source] Synthesis and Application of Prenyl-Derived Photoaffinity ProbesCHINESE JOURNAL OF CHEMISTRY, Issue 7 2009Lingdong LI Abstract Three photoaffinity probes containing isoprenoid chains and an azide group were synthesized using one-pot coupling reaction as the key step. The capability of these probes as labeling agents for isoprenoid chain-interacting proteins from Saccharomyces cerevisiae proteome was validated by photoaffinity reaction and "click" conjunction with the biotin reporter followed by streptavidin blot analysis. [source] | ||||||||||