Solid-Phase Synthesis for Constructing Thiazolotriazinone-Based Compounds Library

We describe the first solid-phase synthesis of thiazolo [4,5-<i>d</i>] [1,2,3] triazin-4(3<i>H</i>)-one derivatives using Merrifield resin. The modular sequence involves Thorpe-Ziegler cyclization, sulfone oxidation, and disulfonate nucleophilic substitution, with each step monitored by real-time ATR-FTIR spectroscopy. Conducted under mild conditions with broad functional group tolerance, the protocol delivered a library of 40 compounds in average stepwise yields of 68-97%, requiring only simple resin washing for purification. This study demonstrates a solid-phase route to thiazolotriazinones and illustrates its applicability in heterocyclic library construction and SAR studies.