Synthesis, Structural Characterization, and In Silico Evaluation of the Salicylidene Schiff Base 4-{( <i>E</i> )-[(2,3-Dihydroxyphenyl)methylidene]amino}-2-hydroxybenzoic Acid as a Promising Scaffold for Human Transthyretin Inhibitor

The Schiff base derived from the condensation of 4-aminosalicylic acid with 2,3-dihydroxybenzaldehyde was synthesized and characterized by using experimental techniques, theoretical calculations, and in silico methods. Single-crystal X-ray diffraction analysis showed that the compound crystallizes in the triclinic <i>P</i>1̅ space group with two molecules in the asymmetric unit, both adopting a zwitterionic keto form. In silico studies predict high gastrointestinal absorption, low toxicity, and potential activity as a transthyretin (TTR) inhibitor, with binding affinity comparable to that of the drug Tolcapone, suggesting that the synthesized compound may be a promising scaffold for a TTR stabilizer.