Synthesis of 2-Arylbenzothiazol-5-amines from N,N-Dialkyl-3-nitroanilines

Abstract

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.

Transition-Metal-Free Synthesis of 2-Substituted Benzothiazoles from Nitrobenzenes, Methylheteroaryl Compounds, and Elemental Sulfur, Based on Nitro-Methyl Redox-Neutral Cyclization

“…Recently, the excellent iron-promoted synthesis of 2-substituted benzothiazoles from nitrobenzenes, elemental sulfur, and benzyl alcohol was reported through the conversion of C–H bonds into C–S bonds (Scheme c). − However, because of the relatively low reactivity of electron-deficient C–H bonds, direct sulfuration with elemental sulfur still presents a challenge.…”