Base-Promoted Synthesis of Quinoline-4(1H)-thiones from o-Alkynylanilines and Aroyl Isothiocyanates

Abstract

A base-promoted synthesis of quinoline-4(1H)-thiones has been accomplished from the in situ generated o-alkynylthiourea, obtained by reacting o-alkynylanilines with aroyl/acyl isothiocyanates. A 6-exo-dig S-cyclization of the in situ generated thiourea is followed by a rearrangement to give quinoline-4(1H)-thiones.

Reaction of β‐(2‐aminophenyl)‐α,β‐Ynones with Tosyl Isocyanate: Experimental and Computational Investigations

“…Microwave‐assisted cascade reactions of 2‐(phenylethynyl)anilines and aryl isothiocyanates led to the synthesis of indolo[2,3‐ b ]quinolones . The reaction of 2‐alkynylanilines with aroyl/acyl isothiocyanates accomplished the synthesis of quinolone‐4(1 H )thiones . Tandem addition‐cyclization reactions of 2‐alkynylaniline derivatives 1 with isocyanates catalyzed by palladium chloride achieved an efficient and practical route for the synthesis of 2‐substituted‐ N ‐1 H ‐indole‐1‐carboxyamides 3 through the regioselective 5‐endo‐dig annulation reaction of the 2‐alkynyl‐phenylurea intermediate 2 (Scheme a) .…”

Annulation of 2‐Alkynylanilines: The Versatile Chemical Compounds

“…The base mediated rearrangement of the latter leads to the ring‐opening, followed by the second cyclization to access quinoline‐4(1 H )‐thiones 44 (Scheme 15). [60] …”

A “Thiocarbonyl‐Directed” Regiospecific C−H/S−H Annulation of Quinoline‐4(1H)‐thiones with Alkynes

“…[8] Quinoline-4(1H)thione scaffold represents a highly privileged and biologically important molecule. [8] Quinoline-4(1H)thione scaffold represents a highly privileged and biologically important molecule.…”

“…Recently, our group reported a base-promoted synthesis of quinoline-4(1H)-thiones from o-alkynylanilines and aroyl isothiocyanates. [8] Quinoline-4(1H)thione scaffold represents a highly privileged and biologically important molecule. [9] In N-(3-phenyl-4thioxo-1,4-dihydroquinolin-2-yl)benzamide (1) moiety, four directing sites viz.…”

“…Recently, our group reported a base‐promoted synthesis of quinoline‐4(1 H )‐thiones from o ‐alkynylanilines and aroyl isothiocyanates . Quinoline‐4(1 H )‐thione scaffold represents a highly privileged and biologically important molecule .…”