Synthesis of functionalized pyridines and thiophenes by Michael addition of some ?-keto carbothioic acid anilides to electrophilic olefins

Abstract

Arylmethylenemalononitrile and conjugate nitroalkenes, being markedly electron deficient, are versatile Michael acceptors for conjugated addition with various compounds containing acidic hydrogen atoms. In majority of reactions the Michael adducts are reactive intermediates that undergo spontaneous cyclization to carbo- [l] or heterocyclic [Z, 31 compounds.Recently we have published the efficient synthesis of various heterocyclic systems that consisted in reactions of arylmethylenemalononitriles with carbanions derived from benzoyl(thioacetani1ide) [4], 1-H-benzimidazole-2-acetonitrile [S] and 1-0x0-cycloalkano-2-carbothioic acid anilides [6]. Continuing our study on application of P-keto acid anilides to the synthesis of heterocyclic compounds we report in this work the results of reactions of 1-0x0-indano-(1) and 1-oxo-1,2,3,4tetrahydronaphthalene-(2) carbothioic acid anilides with benzylidenemalononitrile 3 and (E) p-nitrostyrene (9).

Stereoselective Synthesis of Bridged Azepine Derivatives via Polyfunctionalized Spiroannulated Thiophene. Novel Rearrangement of Oxime Esters

“…The starting materials were 1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbothioic acid arylamides, 1 , , and ( E )-β-nitrostyrenes, 2 . The reaction of 1 with 2 catalyzed by piperidine (Scheme ) afforded spirothiophenes 5a − f in good yields (57%−72%).…”

Substrate‐Controlled Diastereoselectivity Switch in the Formation of Dihydrothieno[3,4‐c]coumarins via [4+1] Annulations

“…Thioamides containing a carbonyl and thiocarbonyl group have been proven to be highly reactive and versatile in the preparation of various sulfur-containing heterocycles. [22,23] We envisioned that the [4 + 1] annulation between thioamide derivative 2H-1-benzopyran-3-carbothioamide 1 a and a-benzoyl dimethylsulfur ylide 2 a, which was used as a diverse reagent to construct complex cyclic molecules, 22 would take place to afford sulfur-containing heterocycles. Interestingly, the initial [4 + 1] annulation of the 2H-1-benzopyran-3-carbothioamide 1 a and a-benzoyl dimethylsulfur ylide 2 a proceeded efficiently at room temperature under catalyst-free conditions ( Table 1).…”

synthesis of Functionalised Polythiophenes and (2-Thienylcarbonyl)Pyrroles Via Conjugate Addition of (2-Thienylcarbonyl)Thioacetanilides to Nitroakenes

“…[5][6][7] The efficiency of this route prompted us extend this methodology to the synthesis of compounds containing two and three thiophene units. [5][6][7] The efficiency of this route prompted us extend this methodology to the synthesis of compounds containing two and three thiophene units.…”