Syntheses of 6-fluoro-meta-tyrosine and of its metabolites

Abstract 6-Fluoro- meta -tyrosine ( 1 ) was prepared from 2-fluoro-5-hydroxybenzaldehyde ( 6 ) based on an Erlenmeyer–Plochl azlactone strategy. Products of expected metabolism of the amino acid, including 6-fluoro- meta -tyramine ( 2 ) and its O -sulfate conjugate ( 3 ), (2-fluoro-5-hydrxoyphenyl)acetic acid ( 4 ), and 6-fluoro- meta -octopamine ( 5 ) also were prepared from 1 . The use of a recently reported ultrasound-catalyzed Henry reaction facilitated the preparation of the tyramine derivative 2 . The compounds synthesized are available for high performance liquid chromatography (HPLC) standards in positron emission tomography (PET) studies employing 6-[ 18 F]fluoro- meta -tyrosine and as reference samples for metabolic studies of the amino acid.