Direct synthesis of aryl substituted pyrroles from calcium carbide: an underestimated chemical feedstock

In this work, a novel synthetic methodology for the preparation of aryl pyrroles directly from the reaction of calcium carbide with oxime is reported. Various pyrrole derivatives are generated from the corresponding oximes in satisfactory yields (49-88%) under the optimized conditions. The one- pot synthesis of aryl pyrrole from widely available ketone is also successfully developed. A new near-infrared fluorescent BODIPY dye containing a phenyl substitution at the C-3 position is expediently prepared from the aryl pyrrole derived from this methodology. The key benefit of this methodology is the use of an inexpensive and less hazardous primary chemical feedstock, calcium carbide, in a wet solvent without any metal catalysts. This process offers a novel cost-efficient route for the synthesis of functionalized pyrrole.