New functionalized 8-hydroxyquinoline-5-sulfonic acid mesoporous silica (HQS-SBA-15) as an efficient catalyst for the synthesis of 2-thiohydantoin derivatives

Mesoporous silica SBA-15 functionalized with 8-hydroxyquinoline-5-sulfonic acid (HQS-SBA-15) was used as a new recyclable nanocatalyst for the one-pot synthesis of 2-thiohydantoin derivatives under solvent-free conditions. The catalyst exhibited excellent recyclability at least for 3 times with a high catalytic activity.