Positive allosteric modulators of 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid receptors belonging to 4-cyclopropyl-3,4-dihydro-2h-1,2,4-pyridothiadiazine dioxides and diversely chloro-substituted 4-cyclopropyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides.
Two 4-ethyl-substituted pyridothiadiazine dioxides belonging to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor positive allosteric modulators were cocrystallized with the GluA2 ligand binding domain in order to decipher the impact of the position of the nitrogen atom on their binding mode at the AMPA receptors. The latter was found to be very similar to that of previously described benzothiadiazine-type AMPA receptor modulators. The affinity of the two compounds for the receptor was determined by isothermal titration calorimetry. Accordingly, the synthesis and biological evaluation of novel 4-cyclopropyl-substituted pyridothiadiazine dioxides was performed and completed with the synthesis of the corresponding chloro-substituted 4-cyclopropyl-3,4-dihydro-2H-benzothiadiazine 1,1-dioxides. The "8-aza" compound 32 was found to be the most potent pyridothiadiazine-type AMPA receptor potentiator in vitro, whereas the 7-chloro-substituted compound 36c emerged as the most promising benzothiadiazine dioxide. Due to proper drug-likeness and low in vivo acute toxicity in mice, 36c was chosen for a more complete preclinical evaluation. The compound was able to easily cross the blood-brain barrier. In an in vivo object recognition test with CD1 mice, oral administration of 36c was found to significantly improve cognition performance at doses as low as 1 mg/kg.
Department of Medicinal Chemistry, Center for Interdisciplinary Research on Medicines (CIRM), University of Liege , Avenue de l'Hôpital, 1, B36, B-4000 Liège, Belgium.
Pierre
P
Francotte
Ann-Beth
AB
Nørholm
Taru
T
Deva
Lars
L
Olsen
Karla
K
Frydenvang
Eric
E
Goffin
Pierre
P
Fraikin
Pascal
P
de Tullio
Sylvie
S
Challal
Jean-Yves
JY
Thomas
Fabrice
F
Iop
Caroline
C
Louis
Iuliana
I
Botez-Pop
Pierre
P
Lestage
Laurence
L
Danober
Jette S
JS
Kastrup
Bernard
B
Pirotte
D000495:Allosteric Site; D000818:Animals; D001581:Benzothiadiazines / Q000737:chemistry*; D002151:Calorimetry; D002626:Chemistry, Pharmaceutical / Q000379:methods; D018360:Crystallography, X-Ray; D003499:Cyclic S-Oxides / Q000737:chemistry*; D019281:Dimerization; D015195:Drug Design; D004594:Electrophysiology; D006624:Hippocampus / Q000187:drug effects; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D007700:Kinetics; D051379:Mice; D010087:Oxides / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry*; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D013829:Thiadiazines / Q000737:chemistry*
C000594748:7-chloro-4-cyclopropyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide; D001581:Benzothiadiazines; D003499:Cyclic S-Oxides; D010087:Oxides; D011422:Propionates; D018091:Receptors, AMPA; D013829:Thiadiazines; D006859:Hydrogen; C029658:propionic acid