7-Phenoxy-Substituted 3,4-Dihydro-2H-1,2,4-benzothiadiazine 1,1-Dioxides as Positive Allosteric Modulators of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors with Nanomolar Potency

Eric Goffin, Thomas Drapier, Anja Probst Larsen, Pierre Geubelle, Christopher P Ptak, Saara Laulumaa, Karoline Rovinskaja, Julie Gilissen, Pascal de Tullio, Lars Olsen, Karla Frydenvang, Bernard Pirotte, Julien Hanson, Robert E Oswald, Jette Sandholm Kastrup, Pierre Francotte

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Abstract

We report here the synthesis of 7-phenoxy-substituted 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides and their evaluation as AMPA receptor positive allosteric modulators (AMPApams). The impact of substitution on the phenoxy ring and on the nitrogen atom at the 4-position was examined. At GluA2(Q) expressed in HEK293 cells (calcium flux experiment), the most potent compound was 11m (4-cyclopropyl-7-(3-methoxyphenoxy)-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide, EC50 = 2.0 nM). The Hill coefficient in the screening and the shape of the dimerization curve in small-angle X-ray scattering (SAXS) experiments using isolated GluA2 ligand-binding domain (GluA2-LBD) are consistent with binding of one molecule of 11m per dimer interface, contrary to most benzothiadiazine dioxides developed to date. This observation was confirmed by the X-ray structure of 11m bound to GluA2-LBD and by NMR. This is the first benzothiadiazine dioxide AMPApam to reach the nanomolar range.

Original languageEnglish
JournalJournal of Medicinal Chemistry
Volume61
Issue number1
Pages (from-to) 251–264
ISSN0022-2623
DOIs
Publication statusPublished - Jan 2018

Keywords

  • Journal Article

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