Synthesis of new functionalized thiazolidin-4-ones by the condensation of thioureas with dialkyl acetylenedicarboxylates

Thiazolidin-4-ones functionalized at the position 5 and their heterocycle-annulated analogues were obtained based on the reaction of thioureas with dialkyl acetylenedicarboxylates. In most cases the reaction proceeds with high selectivity to form 2-iminothiazolidin-4-one-type products.