A series of 6,8-dioxo-3-thia-1,7-diazabicyclo[3.3.0]octanes and a series of 6,8-dioxo-3-thia-1,7-diazabicyclo[3.3.0]octane 2-spiro derivatives were synthesized from L-(-)-R-cysteine ethyl ester in two steps. The synthetic route involved condensation of the amino acid with an appropriate aldehyde or ketone, then a further condensation of the resultant ethyl thiazolidine-4-carboxylate with an isocyanate
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.