title: Structural modifications of (1S,3S)-3-amino-4-difluoromethylenecyclopentanecarboxylic acid, a potent irreversible inhibitor of GABA aminotransferase.
abstract: Low brain levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) lead to convulsions. Inhibition of GABA aminotransferase increases the concentration of GABA and can terminate the convulsions. Earlier we reported the synthesis of (1S,3S)-3-amino-4-difluoromethylenecyclopentanecarboxylic acid (2), which is 186 times more potent an inactivator of GABA aminotransferase than the epilepsy drug S-vigabatrin. The corresponding dichloromethylene analogue of 2 (compound 3) has been made, but it shows only weak reversible inhibition of GABA aminotransferase. However, the tetrazole isostere of 2 (compound 4) has been found to be a time-dependent inactivator of GABA aminotransferase. Although it is 20 times less potent than carboxylic acid 2, it is 2.5 times more potent than S-vigabatrin. A calculation of the ClogP values indicates that 4 is the most lipophilic of the three, being 69 times more lipophilic than 2 and 55 times more lipophilic than S-vigabatrin, indicating potential for improved bioavailability.
authors.affiliation: Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208-3113, USA.
authors.forename: Hai
authors.initials: H
authors.lastname: Yuan
authors.forename: Richard B
authors.initials: RB
authors.lastname: Silverman
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors*; D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000494:pharmacology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D011392:Proline / Q000031:analogs & derivatives; D013329:Structure-Activity Relationship
chemical_list: C519726:(1S,3S)-3-amino-4-difluoromethylenecyclopentanecarboxylic acid; D002264:Carboxylic Acids; D003517:Cyclopentanes; D004791:Enzyme Inhibitors; D011392:Proline; D000612:4-Aminobutyrate Transaminase