摘要:

AbstractRhodamine‐123 (Rh123) was iodinated with123I in presence of Iodogen. Yield of the labelled Rh123 varied greatly depending upon various reaction parameters. Optimum reaction conditions with respect to molarity and pH of the buffer, reaction time, amounts of iodogen, carrier iodide and Rh123, were determined through carefully controlled reactions. Radiochemical yields of 50–60% were obtained within less than 2 hrs. using 0.05M NH4H2PO4buffer at pH5, 200 μg iodogen, 250 μg Rh123 and no‐carrier‐added iodide. Separation of the labelled Rh123 in greater than 98% radiochemical purity was achieved by flash chromatography on silica gel. The overall isolated yield of radioiodinated Rh123 ranged from 25–35% with respect to the added radioiodide. TLC and HPLC methods were developed for analysis of the labell

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280102

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractTwo kappa opiate agonists1and2have been labeled from bromo‐[1‐14C]‐acetic acid and sodium [1‐14C]acetate respe

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280103

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe synthesis of specifically labeled 2,5,8‐trimethyl‐3,4‐dihydro‐1(2H)‐naphthalenone‐2‐d and 3,5,8‐trimethyl‐3,4‐dihydro‐1(2H)‐naphthalenone‐2,2‐d2through α‐proton exchange using neat trifl

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280104

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractPartial reduction of the acetylenic precursor1with carrier‐free tritium gas in the presence of Lindlar catalyst gave the highly labelledcis‐allylic alcohol2. Tritium was thus contained in the metabolically stable 13,14‐position of the lower side chain. Elaboration of2via a fourteen step, microscale sequence gave enprostil‐[13,14‐3H]19having a specific activity of 4

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280105

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractAn efficient and convenient method of preparing17O enriched phenols is described. Aryl boronic acids are oxidized with17O enriched potassium hydroperoxide. The17O labeled potassium hydroperoxide is prepared from the autoxidation reaction of benzhydrol with17O enriched oxygen gas in the presence of potassium t‐butoxide. [0–17]Phenol, p‐bromo[0–17]phenol and p‐methoxy[0–17]phenol were prepared in good to modest overall chemical yields (40–60%) and high isotopic retention (82–90% from 16.8 atom %17O2starting material).17O NMR spectra of the three enriched phenols demonstrate the benefits of using enriched samples in reducing the total experiment time and greatly improving the signal‐to‐noise ratio compared to

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280106

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractAn enzymatic synthesis of [11C]N‐acetyl‐D‐glucosamine is described.11CO2is reacted with methylmagnesium bromide to form [1‐11C]acetate. The latter is converted to [11C]acetylcoenzyme A by passage over an enzyme reactor containing immobilized acetylcoenzyme A synthetase (Acetate: CoA ligase (AMP forming); EC 6.2.1.1).[11C]Acetylcoenzyme A is purified on‐line and concentrated on an anionexchange column. Elution is achieved with 1.5 M glucosamine HCl pH 8.0 and the [11C]acetylcoenzyme A fraction is collected in an ultrafiltration cell containing the enzyme glucosamineN‐acetyltransferase (acetylcoenzyme A: 2‐amino‐2‐deoxy‐D‐glucoseN‐acetyl

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280107

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractEnantiomerically enriched (≥92% e.e.) tritium‐labelled diazoacetate photoaffinity analogs EBDA and EHDA (each 58 Ci/mmol) and EFDA (14 Ci/mmol) were prepared from the corresponding tritiated juvenile hormone (JH) homologs JH I, JH II, and JH III in two steps. Selective reduction of the ester group and subsequent acylation gave the target compou

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280108

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractHigh yield single step preparation of 4′‐18F‐spiperone by18F‐ for NO2exchange in highly basic conditions fails when using 4′‐NO2‐spiperone as a precursor. This compound moreover inhibits radiofluorination of highly activated molecules in mentioned conditions. Inhibition is not provoced by ketalised analogues of the butyrophenone. This led to assume that enolisation of the butyrophenone was responsible for those phenomena. The assumption is supported by the fact that the results of inhibition experiments fit to a theo

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280109

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of varying reaction conditions on the yield of 2‐FDG via the Jülich synthesis (1) has been investigated. The yield is found to be relatively immune to changes in many reaction parameters. On the other hand, we have found that the type of sweep gas used to remove the vapor phase during the azeotropic drying step is critical. The incorporation of18F into the 2‐FDG triflate precursor is reduced fourfold when the sweep gas contains oxygen. However, using either of the inert gases nitrogen or helium as the sweep gas insures a consistent 65%18F incorporation. This phenomena was investigated with proton and19F NMR spectroscopy at the University of Wisconsin. Oxygen in the sweep gas does not alter the proton environment of the phase‐transfer catalyst (Kryptofix K222) but it does change the environment of the18F atom, that is loosely bound to the crown ether, inducing less favorable conditions for the SN2re

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280110

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe synthesis of [1′,3′‐3H]4‐(4′‐azido‐5′,6′,7′,8′‐tetrahydro‐5′,5′,8′,8′‐tetramethyl ‐2′‐anthracenyl)benzoic acid is described. This retinoid was designed as a photoaffinity probe of the receptor sites of cellular retinoic acid‐binding protein and the nuclear retinoic acid receptor protein. The [3H]azidoretinoid was prepared from 1,2,3,4‐tetrahydro‐1,1,4,4‐tetramethyl‐7‐(4‐methylphenyl)‐5‐nitroanthracene in five steps in 15% yield (89% radiochemical purity by HPLC).1H and3H NMR

ISSN:0362-4803    

DOI:10.1002/jlcr.2580280111

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY