Synthesis of [18-C-6]-β3-(L)-DOPA, first β-amino acid with a crown-ether receptor side-chain

Abstract Terminally protected Boc-β 3 -( L )-DOPA-OMe has been synthesized from ( L )-DOPA by the Arndt – Eistert homologation procedure. Then, a first crown-ether derivative, Boc-[18-C-6]-β 3 -( L )-DOPA-OMe, has been obtained by bis- O -alkylation of the catechol function with cyclization, using Cs 2 CO 3 as base and pentaethyleneglycol ditosylate as alkylating agent, in DMF at 60°C.