1
|
Markus A, Schreiber JA, Goerges G, Frehland B, Seebohm G, Schepmann D, Wünsch B. Phenol-Benzoxazolone bioisosteres: Synthesis and biological evaluation of tricyclic GluN2B-selective N-methyl- d-aspartate receptor antagonists. Arch Pharm (Weinheim) 2022; 355:e2200147. [PMID: 35606894 DOI: 10.1002/ardp.202200147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/23/2022] [Accepted: 04/27/2022] [Indexed: 12/20/2022]
Abstract
Tricyclic tetrahydrooxazolo[4,5-h]-[3]benzazepin-9-ols 22 were designed as phenol bioisosteres of tetrahydro-3-benzazepine-1,7-diols. Key features of the synthesis are the introduction of the trifluoromethylsulfonyl and allyl protective groups at the heterocyclic N-atoms. Two methods were developed to convert the triflyl-protected ketone 16 into tricyclic alcohols 21 bearing various N-substituents. According to the first method, trifluoromethanesulfinate was removed by K2 CO3 . Following the selective reduction of the imino moiety of 17 with NaBH(OAc)3 afforded the aminoketone 18, which was reductively alkylated and reduced. According to the second method, both the imine and the ketone of the iminoketone 17 were reduced with NaBH4 to yield the aminoalcohol 20, which was alkylated or reductively alkylated to form tertiary amines 21f-21r. In the last step, the allyl protective group of 21 was removed with RhCl3 and HCl to obtain oxazolones 22. In receptor binding studies using [3 H]ifenprodil as radioligand ketone, 22m showed the highest GluN2B affinity (Ki = 88 nM). However, a reduced affinity toward GluN2B subunit-containing N-methyl- d-aspartate (NMDA) receptors was observed for oxazolones 22 compared to bioisosteric 3-benzazepine-1,7-diols. High selectivity of 22m for the ifenprodil binding site of GluN2B-NMDA receptors over the 1-(1-phenylcyclohexyl)piperidine binding site and σ2 receptors was observed, but only negligible selectivity over σ1 receptors. In two-electrode voltage clamp experiments, the 4-phenylbutyl derivative 22d (Ki = 422 nM) demonstrated 80% inhibition of ion flux at a concentration of 1 µM. The differences in GluN2B affinity and inhibitory activity are explained by docking studies. In conclusion, 22d is regarded as a novel scaffold of highly potent GluN1/GluN2B antagonists.
Collapse
Affiliation(s)
- Alexander Markus
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Julian A Schreiber
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,Department of Cardiovascular Medicine, Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Gunnar Goerges
- Department of Cardiovascular Medicine, Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Bastian Frehland
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany.,GRK 2515, Chemical Biology of Ion Channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,GRK 2515, Chemical Biology of Ion Channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
| |
Collapse
|
2
|
Markus A, Schepmann D, Wünsch B. Synthesis of oxazolo-annulated 3-benzazepines designed by merging two negative allosteric NMDA receptor modulators. Arch Pharm (Weinheim) 2022; 355:e2200020. [PMID: 35224754 DOI: 10.1002/ardp.202200020] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 12/14/2022]
Abstract
To improve the metabolic stability and receptor selectivity of ifenprodil (1), the benzoxazolone moiety of besonprodil (2) and the 3-benzazepone moiety of WMS-1410 (3) were merged to obtain oxazolobenzazepines of type 4. The 5-(hydroxyethyl)benzoxazolone 7 representing the first key intermediate was prepared in four steps starting with the 4-(2-hydroxyethyl)phenol (8). Mitsunobu reaction of primary alcohol 7 with N-sulfonylated glycine esters established the necessary side chain. The intramolecular Friedel-Crafts acylation of acid 12a containing the N-tosyl protective group led upon decarbonylation exclusively to the tricyclic tetrahydroisoquinoline 14. Protection of the amino moiety by the stronger electron-withdrawing triflyl group resulted in the desired 3-benzazepine 15 without the formation of analogous isoquinoline. The triflyl protective group was cleaved off by K2 CO3 -induced elimination of trifluoromethanesulfinate. In a one-pot three-step procedure, various oxazolobenzazepinediones 15 were obtained, which were reduced to afford the desired secondary alcohols 18.
Collapse
Affiliation(s)
- Alexander Markus
- Institut für Pharmazeutische und Medizinische Chemie der Universität Münster, Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie der Universität Münster, Münster, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie der Universität Münster, Münster, Germany.,GRK 2515, Chemical Biology of Ion Channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
| |
Collapse
|