Asymmetric synthesis of L-2-amino[3-11C]butyric acid, L-[3-11C]norvaline and L-[3-11C]valine.
The short-lived radionuclide 11C (t1/2 = 20.4 min) has been used in the asymmetric synthesis of L-2-amino[3-11C]butyric acid, L-[3-11C]-norvaline and L-[3-11C]valine. The syntheses were performed by alkylation of [(+)-2-hydroxypinanyl-3-idene]-glycine tert-butyl ester under anhydrous conditions in tetrahydrofuran/1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone with lithiated 2,2,6,6-tetramethylpiperidine as base, using the appropriate 11C-alkyl iodides prepared in a one-pot reactor from [11C]carbon dioxide. Following removal of the protecting groups, the -[3-11C]amino acids were obtained in 80-82% enantiomeric excess and in 9-25% radiochemical yields, decay corrected and calculated on the basis of the amount of [11C]carbon dioxide at the start of the syntheses within 50-55 min.
Antoni
G
G
Department of Organic Chemistry, University of Uppsala, Sweden.
Långström
B
B
D000478:Alkylation; D000613:Aminobutyrates / Q000138:chemical synthesis*; D055598:Chemical Phenomena; D002621:Chemistry; D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D004952:Esters / Q000032:analysis / Q000138:chemical synthesis; D005463:Fluoroacetates; D007700:Kinetics; D013056:Spectrophotometry, Ultraviolet; D014269:Trifluoroacetic Acid / Q000032:analysis / Q000138:chemical synthesis; D014633:Valine / Q000138:chemical synthesis* / Q000031:analogs & derivatives
D000613:Aminobutyrates; D004952:Esters; D005463:Fluoroacetates; C012223:alpha-aminobutyric acid; C005313:norvaline; D014269:Trifluoroacetic Acid; D014633:Valine