Application of the 2(5 H )furanone motif in the synthesis of new thiopyrano[2,3- d ]thiazoles via the hetero-Diels–Alder reaction and related tandem processes

Novel thiopyrano[2,3-d]thiazole derivatives were synthesized from 5-arylidene-4-thioxo-2-thiazolidinones and 2(5H)furanone in 62–79% yields via hetero-Diels–Alder reactions and related acylation-based tandem processes. The reaction of 5-(4-fluorophenyl)-4-thioxo-2-thiazolidinone with 2(5H)furanone was studied by DFT at the M06-2X/6-31+G(d,p) level. The stereo- and regioselectivities of cycloaddition were confirmed by NMR spectra and single-crystal X-ray diffraction analyses.