SYNTHESIS AND DETERMINATION FOR ENANTIOMERIC PURITY OF 6-FLUORO-L-DOPA

AIM To study the synthesis and determination for enantiomeric purity of 6-fluoro-L-3,4-dihydroxyphenylalanine (6-fluoro-L-DOPA, 6-FDOPA). METHODS 2-(2-Fluoro-4,5-dimethoxybenzyl)-N-(diphenylmethylene)glycine tert-butyl ester (8), a new compound, was synthesized from the starting material nitroveratraldehyde via the nucleophilic displacement, reductive iodination, and chiral catalytic phase transfer alkylation, and 6 FDOPA was prepared from hydrolysis of 8. The enantiomeric purity of 6-FDOPA was determined by HPLC method using a chiral mobil phase and reversed phase C₁₈ column. RESULTS The total time of synthesis was less than 90 min, the overall chemical yield from potassium fluoride was about 33%, and the enantiomeric purity was above 95%. CONCLUSION Large scale production of 6-FDOPA and automatic synthesis of 6-¹⁸Ffluoro-L-DOPA with excellent chemical and entiomeric purity are available. The practical technique was provided for the radiochemical synthesis and entiomeric purity of 6-¹⁸Ffluoro-L-DOPA.