Acid‐Controlled Chemodivergent Synthesis of Three Differently Substituted Quinolines via Site Selective Coupling of ortho‐ Aminoaryl Ketones with α‐Enolic Dithioesters

Abstract

A straightforward approach for the chemodivergent synthesis of quinolines is described through site‐selective coupling of ortho‐aminoaryl ketones with α‐enolic dithioesters (DTEs) under solvent‐free conditions. The operationally and user‐simple one‐pot methodology is based on the trifunctional nature of DTEs. Both the carbonyl and the thiocarbonyl moiety in α‐enolic dithioesters were employed for the efficient construction of three differently substituted quinolines in a chemoselective manner simply by variation of an easy to handle acid catalyst.magnified image

Synthesis of 4‐(Trifluoromethyl)‐2,3‐Dihydrothiazoles from α‐Enolic Dithioesters and Imidoyl Sulfoxonium Ylides

“…It is noteworthy that the annulation reaction of CF 3 ‐imidoyl sulfoxonium ylides with 1,3‐dicarbonyl compounds including β‐ketonesters gave 5‐trifluoromethylpyrroles as reported by Cheng (eq a, Scheme 1). [4a] In addition, annulation reactions triggered by the active metheylene group of α‐enolic dithioester to access 1,3‐thiazines and differently substituted quinolines were demonstrated by us and Singh respectively [6f,i] . By contrast, annulation reactions initiated by the nuclephilic sulfur atom of thiocarbonyl were also disclosed in the literature [6j,k] .…”

Brønsted acid-catalyzed metal-free one-pot synthesis of benzimidazoles via [4+1] heteroannulation of ortho-phenylenediamines with β-oxodithioesters

“…In continuation of our research interests toward the synthetic utility of β-oxodithioesters, [33][34][35][36][37][38][39][40][41] in order to access diverse structurally challenging heterocycles via one-pot solvent-free synthetic protocols, we report herein an operationally simple and straightforward synthesis of benzimidazoles via one-pot domino reaction involving a sequence of imine formation/N-cyclization/C-C bond cleavage cascade in good to excellent yields (Scheme 1). To the best of our knowledge, there is no report for the synthesis of 2-substituted benzimidazoles directly from β-oxodithioesters under solventless metal-free conditions.…”

2‐Mercaptoquinoline Analogues: A Potent Antileishmanial Agent

“…The quinolines under study are prepared according to our earlier report, which is depicted in Scheme . When a mixture of α ‐enolic dithioester 2 (1.0 mmol) and ortho ‐aminoaryl ketone 3 (1.0 mmol), InCl 3 (0.1 mmol) was added and the reaction mixture was heated at 80 o C till the completion of the reaction.…”