摘要:

Abstract(1R)‐(1‐Acetamido‐2‐phenylethyl)boronic acid‐1‐13C, which is the boron analogue ofN‐acetylphenylalanine, has been synthesized via a modification of the route previously established for the unlabelled compound. The13C label is derived from dichloromethane‐13C. The previous conditions utilized excess dichloromethane, but it has now been found that a stoichiometric amount of dichloromethane suffices for the preparation of (dichloromethyl)lithium and its reaction with a boronic ester. Thus, the method has broad potential for the synthesis of compounds bearing13C lebels at chiral sites. The1H and13C NMR spectra of the target compound and the intermediates leading to i

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310802

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe synthesis of [125I]iodobuprenorphine is described. This compound has been used as a tracer molecule in the development of a new radioimmunoassay for buprenorphine. The parameters that effect the direct iodination of buprenorphine using sodium [127I]iodide, in the presence of either chloramine‐T or Iodo‐Beads®, were previously studied. The structure of iodobuprenorphine was confirmed by mass spectrom

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310803

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe chemical synthesis of 99% enriched D(‐)‐[1,7‐13C2]shikimic acid from [1,2‐13C2]acetate in 25% overall yield is described. A two‐carbon phosphonate synthon was prepared from [1,2‐13C2]acetate and used in the shikimate synthesis of Fleet an

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310804

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractReported is the synthesis of [14C]‐L‐N‐[(trimethylamineboryl)carbonyl]‐phenylalanine methyl ester, a boron containing α‐amino acid dipeptide analog with anti‐neoplastic, anti‐inflammatory, and hypolipidemic activities. The14C label is universally distributed among all carbon positions of the phenylalanine portion of the molecule. Briefly, the dipeptide is prepared by reacting the phenylalanine methyl ester hydrochloride salt with trimethylamine‐carboxyborane, triphenylphospine (TPP), CCl4, and triethylamine (TEA) in acetonitrile, for 24 hours. The final product afforded a specific activity

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310805

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractSyntheses of tritium labeled guanidineacetic acid sweetener and a tritiated photoaffinty labeling reagent via the catalytic hydrogenation of the dibromo intermediates are described. These labeled compounds were required for the investigation of sweet taste mechanism.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310806

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractImidacloprid is an exceptionally potent insecticide known from physiological studies to act at the nicotinic acetylcholine receptor. To prepare [3H]imidacloprid as a candidate radioligand, 6‐chloronicotinoyl chloride was reduced with NaB2H4(in model studies) or NaB3H4in absolute ethanol to 2‐chloro‐5‐pyridinylmethanol which was transformed to 2‐chloro‐5‐chloromethylpyridine on refluxing with thionyl chloride. Coupling with 4,5‐dihydro‐N‐nitro‐1H‐imidazol‐2‐amine then gave [2H2]imidacloprid incorporating about 95% of the deuterium or [3H2]imidacloprid (25 Ci/mmol) in 80% radiochemical yield. In studies not detailed here [3H]imidacloprid was found to undergo high affinity, specific and saturable bindin

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310807

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

Abstract[2‐14C]Pyridostigmine bromide was prepared in 17.6% radiochemical yield with specific activity of 18 mCi/mmol. The reaction sequence involved preparation of 2‐furan[14C]carboxylic acid by carbonation of 2‐lithiofuran, followed by conversion to 2‐amino[14C]methyl furan by lithium aluminum hydride reduction of its carboxamide. Oxidative rearrangement of 2‐amino[14C]methylfuran gave 3‐hydroxy[2‐14C]pyridine which was converted to [2‐14C]pyridostigmine bromide by reaction with dimethylcarbamyl chloride and quarternization with bromomethane. Pyridostigmine bromide labeled in the methyl group of the carbamate function was prepared in 73% yield with specific activity of 37.6 mCi/mmol by reaction of bis‐3‐pyridyl carbonate with [14C]dimethylamine followed by quarternization with bromomethane. [6‐3H]‐Pyridostigmine bromide with specific activity of 22.5 mCi/mmol was prepared by catalytic halogen‐tritium replacement of 2,6‐dibromo‐3‐dimethylcarbamyloxypyridine followed by quarternization with bromomethane and back

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310808

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractHexenols are important flavour components of fruit and vegetables. We report the synthesis ofcis‐3‐hexen‐1‐ol‐6,6,6‐2H3, hexen‐1‐ol‐6,6,6‐2H3, hexan‐1‐ol‐6,6,6‐2H3,cis–2‐hexen‐1‐ol‐6,6

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310809

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractPhosphorus pentachloride can be treated with stoichiometric amounts of oxygen‐labelled water to produce 80–90 percent yields of labelled inorganic phosphate when the reaction is conducted in dioxane. Any phosphorus‐chlorine bonds remaining at the end of the reaction are eliminated by reaction with diethylamine prior to adding

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310810

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:0362-4803    

DOI:10.1002/jlcr.2580310801

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY