Utilization of caffeine carbon supported cobalt catalyst in the tandem synthesis of pyrroles from nitroarenes and alkenyl diols

Single‐Atom Cobalt‐Catalyzed Transfer Hydrogenation of Azides and One‐Pot Synthesis of Pyrroles

“…Subsequently, cis ‐butenediol ( 1 c ) (0.6 mmol), NaOMe (0.1125 mmol) and toluene was added to the reaction mixture, heated at 150 °C for 24 h, which delivered 45% yield of N ‐substituted pyrrole 1 d (entry 1). Next, several cobalt catalysts [13h,17] reported from our group were screened, where Co‐pc/C‐800 found to be the most efficient for this transformation (entries 2–4). Later, in the same condition, upon increasing the catalyst amount to 4.2 mol%, the yield of 1 d was improved to 54% (entry 2).…”

Harnessing alcohols as sustainable reagents for late-stage functionalisation: synthesis of drugs and bio-inspired compounds

“…Kundu and co-workers developed an interesting method for the synthesis of novel heterogeneous cobalt catalysts using waste spent coffee grounds (SCC) from the coffee industry as a porous carbon support. 145 These SSC are significantly nitrogen (1.8–3.4%) and carbon enriched and are crucial for modifying the electrical properties of the support and metals for enhanced catalytic activity (method Zo, Scheme 69). These catalysts were quite efficient for the synthesis pyrrole from nitroaniline 165 and 1,4-butyne-diol 166 or 1,4-butene-diol 167 .…”

Greening up organic reactions with caffeine: applications, recent developments, and future directions

“…Several caffeine carbon-supported cobalt-based heterogeneous catalysts viz. Co(OAc) 2 -CC- T , ( T = 700 °C, 800 °C, 900 °C) were prepared by Panja and co-workers 71 ( Scheme 48 ) and their catalytic potential was studied for the synthesis of pyrroles 123 by coupling between nitroarenes 120 and diols 121a–b. Among all the catalysts Co(OAc) 2 -CC-800 exhibited the highest catalytic activity for this transformation ( Scheme 49 ).…”