title: Conformationally rigid N-acyl-5-alkyl-L-prolyl-pyrrolidines as prolyl oligopeptidase inhibitors.
abstract: In the N-acyl-L-prolyl-pyrrolidine type of prolyl oligopeptidase inhibitors the L-prolyl group was replaced by different 5-alkyl-L-prolyl groups, resulting in a series of N-acyl-5-alkyl-L-prolyl-pyrrolidines. Since N-amides of 5-alkyl-L-prolines are conformationally more rigid than those of L-proline, the main objective was to make more rigid prolyl oligopeptidase inhibitors. In the series of compounds where the N-acyl group was a Boc group, the 5(R)-tert-butyl group increased the potency strongly. A similar effect was not observed for the 5(S)-tert-butyl group. In the series of compounds where the N-acyl group was a 4-phenylbutanoyl group, the 5(R)-tert-butyl, 5(R)-methyl and 5(S)-methyl groups did not have an effect on the potency [the 5(S)-tert-butyl group was not tested in this series]. As an additional effect, the 5-tert-butyl groups increased the log P of the compounds 1.5 log units, which might be beneficial when targeting the compounds to the brain.
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kuopio, PO Box 1627, FIN-70211, Kuopio, Finland. wallen@uku.fi
authors.forename: Erik A A
authors.initials: EA
authors.lastname: Wallén
authors.forename: Johannes A M
authors.initials: JA
authors.lastname: Christiaans
authors.forename: Taija J
authors.initials: TJ
authors.lastname: Saarinen
authors.forename: Elina M
authors.initials: EM
authors.lastname: Jarho
authors.forename: Markus M
authors.initials: MM
authors.lastname: Forsberg
authors.forename: Jarkko I
authors.initials: JI
authors.lastname: Venäläinen
authors.forename: Pekka T
authors.initials: PT
authors.lastname: Männistö
authors.forename: Jukka
authors.initials: J
authors.lastname: Gynther
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D006801:Humans; D008968:Molecular Conformation; D000085822:Prolyl Oligopeptidases; D011759:Pyrrolidines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D013552:Swine
chemical_list: D011759:Pyrrolidines; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases; C000705287:PREPL protein, human; D000085822:Prolyl Oligopeptidases