Reactivity Studies and Synthetic Strategies Towards the Preparation of New Hydrophilic Indirubin-Triazole-Based Compounds

Indirubin is an isomer of the blue dye indigo. It is widely used in Chinese medicine as part of therapy against many diseases and, thus, its skeleton becomes a promising candidate for new drug prototypes. Since it has low solubility, its properties could be improved through the insertion of hydrophilic and pharmacophoric groups, such as sugars bridged to 1,2,3-triazoles. Here, we report the synthesis of indirubin-based compounds evaluating two different routes: via the aldol condensation reaction of triazole-isatin derivatives with 3acetoxyindole (pathway A) and reductive coupling of isatin, followed by N-propargylation of indirubin. We also performed reactivity studies guided by density functional theory (DFT) calculations (pathway B). As a demonstration, we simulate interactions with the glycogen synthase kinase 3 beta enzyme, which is associated with neurodegenerative diseases, through both molecular docking and molecular dynamics simulations.