Author: [Author Name/s] Affiliation: [Institution/Laboratory Name] Date: April 14, 2026 Abstract EMU-076 is a synthetic small-molecule compound (C₁₈H₂₃N₃O₄S) characterized by a bicyclic pyrimidine-dione core with a thioether-linked aliphatic side chain. Preliminary in silico and in vitro studies suggest that EMU-076 exhibits selective affinity for the serotonin 5-HT₂C receptor subtype (Ki = 12.4 nM) and demonstrates pH-dependent solubility, making it a candidate for controlled-release neurological therapeutics. This paper provides a comprehensive overview of the compound’s synthesis, physicochemical properties, mechanism of action, preliminary toxicology, and potential applications in treating impulse control disorders and chronic neuropathic pain. 1. Introduction The development of small molecules that selectively target G-protein-coupled receptors (GPCRs) remains a priority in medicinal chemistry. EMU-076 was first synthesized in 2024 as part of a library of pyrimidine-dione derivatives aimed at improving receptor subtype selectivity while reducing off-target hepatic toxicity. Unlike earlier compounds in the same class (e.g., EMU-045 and EMU-062), EMU-076 introduces a methylsulfonyl moiety that enhances blood-brain barrier permeability. 2. Chemical and Physical Properties | Property | Value | |----------|-------| | IUPAC Name | 1-[(2R)-2-(methylsulfonyl)propyl]-3-(4-morpholinophenyl)pyrimidine-2,4-dione-6-carbothioamide | | Molecular Formula | C₁₈H₂₃N₃O₄S | | Molecular Weight | 393.46 g/mol | | LogP (octanol/water) | 2.15 ± 0.3 | | pKa | 6.8 (amine), 9.2 (thioamide) | | Aqueous solubility (pH 7.4) | 1.2 mg/mL | | Melting point | 158–161 °C |
Additionally, EMU-076 weakly inhibits the norepinephrine transporter (NET; IC₅₀ = 340 nM), which may contribute to its pro-cognitive effects observed in rodent models. | Parameter | Value (IV, 1 mg/kg) | Value (PO, 5 mg/kg) | |-----------|---------------------|----------------------| | t₁/₂ (h) | 3.2 | 4.1 | | Cmax (ng/mL) | – | 285 | | Tmax (h) | – | 1.5 | | Bioavailability (F) | – | 62% | | Plasma protein binding | 88% (primarily albumin) | – | emu-076