Crotonic, cynnamic, and propiolic acids motifs in the synthesis of thiopyrano[2,3-d][1,3]thiazoles via hetero-Diels–Alder reaction and related tandem processes

Hetero-Diels–Alder reactions of hetaryl thiochalcones with acetylenic dienophiles

“…In most cases the studied thia-hetero-Diels-Alder reactions comprised reactions of other types of thia-heterodienes, such as enaminothiones [5] or α,β-unsaturated thioamides [5,6]. In a series of recent publications, 5-arylidene-4-thioxo-2-thiazolidinones were used as more complex 1-thia-1,3-dienes in reactions with diverse ethylenic dipolarophiles [7][8][9][10]. Furthermore, a few thia-hetero-Diels-Alder reactions of diverse 1-thia-1,3-dienes (but not thiochalcones !)…”

“…Furthermore, a few thia-hetero-Diels-Alder reactions of diverse 1-thia-1,3-dienes (but not thiochalcones !) with propiolates [6,7], benzynes [11], and an intramolecular reaction with a propargyl ether [12] are known.…”

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

“…1,2 The bond forming economy, high regio-and stereoselectivity, and the general structures thus formed are the main advantages of such reactions. [3][4][5][6][7][8] These reactions proceed smoothly with exclusive regioselectivity and form products according to frontier molecular orbital (FMO) theory. Thus, in earlier reports these compounds were synthesized via the hetero-Diels-Alder reaction of 5-arylidene-4-thioxo-2thiazolidinones (5-arylideneisorhodanines), which contain the heterodiene fragment С=С-С=S, and α,β-unsaturated maleic anhydride and maleimides, as well as arylidene pyruvic, fumaric, and cinnamic acid derivatives as active dienophiles.…”

Arylidene Pyruvic Acids Motif in the Synthesis of New 2H,5H-Chromeno[4′,3′:4,5]thiopyrano[2,3-d]thiazoles via Tandem Hetero-Diels–Alder-Hemiacetal Reaction

“…Earlier we reported the diastereoselective tandem acylation-hetero-Diels-Alder reaction of 5-arylidene-4-thioxo-2-thiazolidinones (5-arylideneisorhodanines) with ortho-phenolic group at arylidene moiety and α,β-unsaturated carboxylic acids derivatives providing 2H,5H-chromeno [4',3':4,5]thiopyrano [2,3-d]thiazoles formation. [15,17] As a consequence, we decided to investigate the reaction between 5-(ortho-hydroxybenzylidene)-substituted isorhodanines and arylidene pyruvic acids (APAs) as dienophiles. The classical regioand diastereoselective hetero-Diels-Alder reaction between 5-arylideneisorhodanines (without ortho-phenolic group at arylidene moiety) and APAs providing novel rel-(5R,6S,7S)-2-oxo-5,7-diaryl-3,5,6,7-tetrahydro-2H-thiopyrano[2,3-d]thiazol-6-yl-oxoacetic acids has been already reported in our research before.…”