First Synthesis for Bis-Spirothiazolidine Derivatives as a Novel Heterocyclic Framework and Their Biological Activity

Background: Spirothiazolidines are versatile synthetic scaffold possessing wide spectrum of biological interests involving potential anticancer activity. Objective: To report the first synthesis of Bis Spiro-thiazolidine as a novel heterocyclic ring system. Methods: One-pot three-component reaction including condensation of p-phenyllene diamine; cyclohexanone and thioglycolic acid produced Spiro-thiazolidine 4, which underwent further condensation with cyclohexanone and thioglycolic acid with equimolar ratio to introduce Bis-Spiothiazolidine 5 as the first synthesis. Also, bis spiro-thiazolidine arylidene derivatives 6-13 were synthesized by the reaction of Bis-Spiothiazolidine 5 with different aromatic benzaldehydes. Results: Four compounds 13, 12, 9 and 11 have shown highly significant anticancer activity compared to Doxorubicin® (positive control) against Human liver carcinoma (HepG2) and Human Normal Retina pigmented epithelium (RPE-1) cell lines. Conclusion: The novel bis-spirothiazolidine deriviatives have been synthesized for the first time and showed excellent anticancer activities compare with the corresponding spirothiazolidine derivatives.