Heterocyclic scaffolds targeting IDO1: progress in medicinal chemistry and clinical development

<p>This review mainly aims to systematically compile and analyze recently developed indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors reported over the past 5 years, with emphasis on heterocyclic scaffold-based classification, structure–activity relationships (SAR), and therapeutic relevance.</p> <p>A comprehensive literature survey was conducted to identify IDO1 inhibitors, which were categorized based on their core heterocyclic scaffolds.

Studies involving biological evaluation, SAR analysis, and molecular docking were critically assessed.</p> <p>IDO1 inhibitors were classified into diverse scaffolds, including indoles, imidazoles, phenyl urea–benzimidazoles, azoles, imidazopyridines, benzofurans, quinolines, pyrimidines, erlotinib-based analogues, naphthoquinones, hydroxyamidine derivatives, quinazolines, and sulfonamide chromone-oxime analogues. Key SAR trends and biological activities were highlighted.