Easy one-pot synthesis of multifunctionalized indole-pyrrole hybrids as a new class of antileishmanial agents.

A chemoselective one-pot synthesis of pharmaceutically prospective indole-pyrrole hybrids by the formal [3 + 2] cycloaddition of 3-cyanoacetyl indoles (CAIs) with 1,2-diaza-1,3-dienes (DDs) has been developed. The new indole-pyrrole hybrids were phenotypically screened for efficacy against Leishmania infantum promastigotes. The most active compounds 3c, 3d, and 3j showed IC50 < 20 µM and moderate cytotoxicity, lower than miltefosine. Compound 3d was the most active with IC50 = 9.6 µM and a selectivity index of 5. Consequently, 3d could be a new lead compound for the generation of a new class of antileishmanial hybrids.

Practical, scalable, and transition metal-free visible light-induced heteroarylation route to substituted oxindoles.

The synthetic application of (hetero)aryl radicals in organic synthesis has been known since the last century. However, their applicability has significantly suffered from ineffective generation protocols. Herein, we present a visible-light-induced transition metal-free (hetero)aryl radical generation from readily available (hetero)aryl halides for the synthesis of 3,3'-disubstituted oxindoles. This transformation is amenable to a wide range of (hetero)aryl halides as well as several easily accessible acrylamides, and it is also scalable to multigram synthesis. Finally, the versatility of the oxindole products is demonstrated through their conversion to a variety of useful intermediates applicable to target-directed synthesis.