摘要:

AbstractPreparation of [11C]methyltriphenylphosphonium iodide and thein situgeneration of [11C]methylenetriphenylphosphorane directly from [11C]methyl iodide, is described. Using this one‐pot preparation, [β‐11C]styrene was synthesized conveniently, fast and with a minimum of manual handling. The synthesis was performed by using [11C]methyl iodide, triphenylphosphine, epichlorohydrin and benzaldehyde in tetrahydrofurane/o‐dibromobenzene, with a synthesis time of 40 min (counted from the end of [11C]methyl iodide transfer), a radiochemical yield of 80–90% of [β‐11C]styrene and a specific radioactivity, of 100MBq/μmol. In a typical experiment starting with 960 MBq11C‐methyl iodide, 200 MBq of [β‐11C]styrene was obtai

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281002

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA high‐performance gel permeation chromatographic separation method was developed for the isolation and characterisation of high molecular weight [3H]hyaluronic acid. The molecular characteristics of the labelled sample were MW=3.92x105Da, MW/Mn=1.5

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281003

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

Abstract[6,7,14,15‐2H4)‐Leukotriene B4methyl ester was prepared by reduction with deuterium gas of a suitable precursor (deuterium incorporation ≥ 90%). Several catalytic semi‐hydrogenations were effected in order to determine the best conditions for the labeli

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281004

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

Abstract[14C]SR 33557 was synthesized in six steps and in an overall yield of 3.8% from sodium [14C]cyanide.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281005

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractUtilizing the facile acylative annulation of 2‐methoxypropene with [1‐14C]malonyl dichloride (5), the synthesis of 1,3,5‐trimethoxy[1‐14C]benzene (8) was accomplished through a seven‐step sequence starting from potassium [14C]cyanide with an overall yield of 60%.Thus, reaction of bromoacetic acid with potassium [14C]cyanide gave sodium [14C]cyanoacetate (1). Hydrolysis of1with sodium hydroxide solution provided the sodium salt of [1‐14C]malonic acid (2). Treatment of2with calcium chloride gave the calcium salt3, which was acidified with concentrated sulfuric acid in ether to give [1‐14C]malonic acid (4). Reaction of4with oxalyl chloride in refluxing ether gave [1‐14C]malonyl dichloride (5). Annulative acylations of 2‐methoxypropene with5gave the crucial intermediate 5‐methoxy[1‐14C]resorcinol (7), together with 4‐hydroxy‐6‐methyl‐[2 (or 4)‐14C]2H‐pyran‐2‐one (6), in a ratio of 3: 1. However,6could be advantageously converted to7aby initial 0‐methylation with dimethyl sulfate, followed by rearrangement of the product, 4‐methoxy‐6‐methyl[2(or 4)‐14C]2H‐pyran‐2‐one (6a), upon treatment with sodium methoxide. Finally,bis‐0‐methylation of7and7awith dimet

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281006

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractCP‐88,818 (β‐tigogenin cellobioside) is a novel hypocholesterolemic and anti‐atherosclerosis agent which acts by inhibiting the absorption of dietary and biliary cholesterol. While the exact mechanism of this inhibition is unclear, CP‐88,818 is believed to block cholesterol absorption without entering the body. In order to prove this hypothesis, radiolabelled CP‐88,818 was needed. Herein, we report the stereoselective synthesis of [5,6‐3H2]CP‐88,818 in four steps from dio

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281007

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe phosphonium compounds, [(Z) and (Z/E)‐(1‐bromo‐1‐penten‐5‐yl)]triphenylphosphonium iodides (yield, 65–70%) and the corresponding bromine‐82‐labeled analogues have been prepared as potential myocardial imaging agents. The 2/1 isomer composition of the Z/E mixture has been confirmed by single crystal X‐ray analysis. The radiobrominated (Z)‐isomer and (Z/E)‐mixture both show high heart uptake and high heart/blood ratios in rats. These data suggest that the bromine‐75 and bromine‐76‐labeled agents could be good candidates for myocardial imaging using positron

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281008

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractIn order to provide a method for in vivo and in vitro detection of cryptand [2.2.2], tritiated cryptand was synthesized by reduction of appropriate bicyclic diamide with tritiated diborane. As part of this synthesis, tritiated diborane was synthesized by the reaction of tritiated sodium borohydride with boron trifluoride etherate and trapped in dry THF. This is a potentially useful agent for selective tritiation of molecules with functional groups which are prone to electrophilic attack.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281009

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

Abstract15N labeled tetranitromethane, C(15NO2)4, was prepared from anhydrous nitric acid and acetic anhydride. A procedure for the preparation of the nitric acid from Na15NO3is described. Tyrosine was nitrated with H15NO3and its15N NMR spectrum compared well with that of tyrosine nitrated with C(15NO2)4.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281010

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe title compound was synthesized at the gram level in 66% yield by addition of [34S]thioacetic acid to α‐acetamidoacrylic acid, followed by acid hydrolys

ISSN:0362-4803    

DOI:10.1002/jlcr.2580281011

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY