In this contribution, we provide a comprehensive overview on the CÀ H activation/functionalization reactions of 1-aryl-5-pyrazolones, in particular, 1-aryl-3-methyl-1H-pyrazol-5(4H)-ones (edaravones) and their N-methyl analogues i. e., antipyrines covering the literature since 2013 (the year of the first report). This review summarizes the recent progress in CÀ H functionalization reactions of 1-aryl-5-pyrazolones including edaravone and antipyrine derivatives under transition-metal-catalyzed/free conditions and discusses the related mechanism according to the role of the catalytic species.

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A facile synthetic protocol has been established for the Nchlorosuccinimide (NCS) promoted direct CÀ H thiocyanation of 1-aryl-5-pyrazolones via in situ-generated electrophilic thiocyanating agent at room temperature. The current protocol features easy performance, mild conditions and short reaction time using readily available starting materials. The DFT studies suggested that ionic process is likely to be involved in this transformation yielding the targeted product with the most stable enaminone form as the favoured tautomer.

A facile synthetic strategy has been established for the microwave‐assisted construction of two C−C bond via regioselective double arylation of imidazo[1,2‐a]pyridines with 1,2‐diiodobenzene by employing Pd(OAc)2 as a catalyst. The current protocol exhibited a simple, efficient and ligands free synthesis of 1‐phenylbenzo[a]imidazo[5,1,2‐cd]indolizine derivatives in good to excellent yields. This Pd‐catalyzed dual arylation provided a valuable tool for the discovery of fluorescent materials.