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Preparation of [ 11 C]diethyl oxalate and [ 11 C]oxalic acid and demonstration of their use in the synthesis of [ 11 C]‐2,3‐dihydroxyquinoxaline
Author(s) -
Thorell JanOlov,
StoneElander Sharon,
Elander Nils
Publication year - 1993
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580331102
Subject(s) - chemistry , oxalic acid , oxalate , cyanide , nitrile , ethyl chloroformate , aqueous solution , nuclear chemistry , carbon 14 , organic chemistry , medicinal chemistry , quantum mechanics , physics
Abstract A method for the production of two new carbon‐11 labelled difunctional radiolabelling precursors, [ 11 C]diethyl oxalate, 2 , and [ 11 C]oxalic acid, 3 , is described. Methyl chloroformate was reacted with no‐carrier‐added [ 11 C]cyanide to generate the intermediate nitrile, methyl [ 11 C]cyanoformate. Alcoholysis with HCl in ethanol generated 2 , with could subsequently be converted to 3 , with aqueous acid. The total time of preparation from end‐of‐trapping of [ 11 C]cyanide was 6‐7 min using combined microwave and thermal treatment or, by exclusively thermal treatment, 15 and 20 min for 2 and 3 , respectively. The radiochemical conversion of [ 11 C]cyanide to 2 and 3 was ∼80% and ∼70%, respectively. Both 2 and 3 were used in a model reaction with 1,2‐phenylenediamine to synthesize the heterocyclic compound, 2,3‐dihydroxyquinoxaline, a basic structural unit in antagonists for the excitatory amino acid receptor system.