The synthesis of 4-arylsulfanyl-substituted kainoid analogues from trans-4-hydroxy-l-proline

The potent neuroexcitatory activity of kainoid amino acids in the mammalian CNS places new analogues in high demand as tools for neuropharmacological research. A range of 4-arylsulfanyl-substituted kainoids has been synthesised in a parallel fashion via mesylate displacement by a number of aromatic thiolates upon (2S,3S,4R)-1-benzoyl-3-tert-butoxycarbonylmethyl-4-methanesulfonyloxypyrrolidine-2-carboxylic acid methyl ester 9, which is obtainable in eight steps from trans-4-hydroxy-l-proline 5.