Synthesis of thieno[2,3-b]pyridinones acting as cytoprotectants and as inhibitors of [3H]glycine binding to the N-methyl-D-aspartate (NMDA) receptor.
The standard glycine site antagonist of the N-methyl-D-aspartate (NMDA) receptor, 3-phenyl-4-hydroxyquinolin-2(1H)-one (21), was used as a template for bioisostere benzene/thiophene exchange. Phenylacetylation of aminothiophene carboxylic acid methyl esters and subsequent cyclization delivered the three possible thienopyridinone isomers. 4-Hydroxy-5-phenylthieno[2,3-b]pyridin-6(7H)-one (3a), with the shortest distance between the sulfur and the nitrogen atom, was the most potent isomer (K(i) against the binding of [(3)H]glycine to rat membranes 16 microM), comparable in potency to the model quinolinone (21, 12 microM). Replacement of the phenyl substituent of 21 by a 2-thienyl residue resulted in a 2-5-fold loss in potency and was abandoned. In the thieno part of the thienopyridinone nucleus, the most successful substituents were halogen (Cl or Br) close to the sulfur atom and short alkyl chains at the other position, resulting in 7h, 8h, 8i, and 8m, with K(i) values between 5.8 and 10.5 nM. Introduction of a 3'-phenoxy moiety yielded several compounds with still higher potencies (18h, 18i, 18l, and 18m; K(i) between 1.1 and 2.0 nM). Quantitative structure-activity relationship (QSAR) calculations resulted in a consistent interpretation of the potencies of most compounds. Several of these 3'-phenoxy derivatives protected mouse fibroblast cell lines with transfected NMDA receptors from glutamate-induced toxicity. In addition, we report in vivo results for four of these compounds.
Buchstaller
Hans-Peter
HP
Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, D-60439 Frankfurt/Main, Germany.
Siebert
Carsten D
CD
Steinmetz
Ralf
R
Frank
Ina
I
Berger
Michael L
ML
Gottschlich
Rudolf
R
Leibrock
Joachim
J
Krug
Michael
M
Steinhilber
Dieter
D
Noe
Christian R
CR
D000818:Animals; D001667:Binding, Competitive; D001812:Blood-Brain Barrier / Q000378:metabolism; D002460:Cell Line; D019610:Cytoprotection; D004597:Electroshock; D005998:Glycine / Q000378:metabolism* / Q000633:toxicity; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011728:Pyridones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D021281:Quantitative Structure-Activity Relationship; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012640:Seizures / Q000209:etiology / Q000517:prevention & control; D013876:Thiophenes / Q000737:chemistry*; D014162:Transfection
C120997:NR2A NMDA receptor; D021122:Protein Subunits; D011728:Pyridones; D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D013876:Thiophenes; D005998:Glycine