We report a method for coupling of nitroarenes, 2- or 4-methylazaarenes, and elemental sulfur to afford (2-pyridyl)aryl thioamides. Good tolerance of functionalities was observed, including primary and secondary amines, bromo, iodo, ester, and boronic ester groups. Thioamides derived from pyrazole, thiazole, quinoline, quinoxalines, and azoles were obtained in good yields, showing the compatibility of heterocycles. This appears to be a general method to obtain pyridyl thioamides in one step from commercial, simple substrates.

We report a simple method for coupling of N,N-dialkyl-3-nitroarenes, elemental sulfur, and activated sp3 C–H bonds in 2-methylazaarenes or arylacetic acids to afford derivatives of 2-arylbenzothiazol-5-amines. Only DABCO base was required, and many heterocycles such as imidazoles, oxazoles, quinolines, and thiophenes were compatible with the reaction conditions. Our approach offers a simple route to useful substituted thiazol-5-amines from commercially available nitroarenes.

Oxidation of sp³ C–H bonds in acetophenones is exploited to annulate with 1,2-phenylenediamines.

No abstract

Methods to afford pyrrolo[1,2-α]quinoxalines often require the use of prefunctionalized aniline precursors, transition metals, and/or harsh conditions. Herein we describe a simple coupling of 1-(2-nitroaryl)pyrroles and arylacetic acids, in the presence of elemental sulfur, to furnish the fused heterocycles in good yields. The conditions were compatible with many functionalities including ester, nitrile, halogen, and nitro groups. Use of benzyl alcohols and picoline coupling reagents was also attempted.