JNJ-7891118

Compound 12 is a potent and selective negative allosteric modulator (NAM) of the GluN2A-containing NMDA receptor, acting at the GluN1–GluN2A interface. It exhibits an IC₅₀ of 40 nM in a calcium flux assay using recombinant GluN1/2A receptors, with > 1250-fold selectivity over GluN2B, GluN2C, and GluN2D subtypes (> 50 µM). Within the broader iGluR class, the compound shows no meaningful inhibition of other glutamate receptor subtypes and has a clean off-target profile based on analog screening against a 77-target CEREP panel. Physicochemical and ADME parameters are favorable for cellular use, including a TPSA of 90 Ų, log D = 2.6, good permeability (Papp = 27 × 10⁻⁶ cm/s), minimal efflux (BA/AB = 0.91), and microsomal stability = 12 µL min⁻¹ mg⁻¹ in human liver microsomes. Solubility at physiological pH (25 µM) supports cell-based assays. No cytotoxicity was reported up to 10 µM. An inactive control (compound 14, IC₅₀ = 48 µM) and the structurally distinct GluN2A NAM MPX-007 serve as appropriate orthogonal comparators. We recommend using compound 12 at ≤ 0.3 µM in cell-based experiments, together with the matched inactive control 14 and orthogonal NAM MPX-007 to confirm target-dependent effects. Overall, compound 12 fulfils all classical probe criteria and is recommended as a high-quality in vitro probe for selective modulation of GluN2A. Compound 12 displays favorable pharmacokinetic and physicochemical characteristics that support its consideration as a candidate GluN2A NAM probe for in vivo studies, though further validation is warranted. In rats, after 1 mg/kg IV dosing, the compound shows a clearance of 41 mL min⁻¹ kg⁻¹, half-life = 0.6 h, and volume of distribution = 1 L kg⁻¹. At 5 mg/kg oral dose, bioavailability reaches 28%, indicating adequate absorption for systemic studies. The low P-gp efflux ratio (0.91) and physicochemical similarity to compound 11 (which achieved 42% receptor occupancy at 25 mg/kg PO and Kpu,u = 0.93) suggest that compound 12 is also likely brain-penetrant and capable of achieving free brain concentrations near its in vitro IC₅₀. No adverse effects were observed in rats up to 5 mg/kg, and metabolic stability and solubility are improved relative to MPX-004/007. However, direct in vivo target engagement has not yet been demonstrated. Until receptor occupancy or pharmacodynamic confirmation is available, compound 12 should be considered a qualified in vivo tool, suitable for exploratory studies of GluN2A function when used alongside the validated analogue compound 11 and the radioligand [³H]-1.