No abstract

Electrochemical synthesis of polysubstituted sulfonated pyrazoles from enaminones and sulfonyl hydrazides was established under metal-free, exogenous-oxidant-free, and mild conditions. By judicious choice of different electrochemical reaction conditions, NH 2-functionalized enaminones or N,N-disubstituted enaminones can react with aryl/alkyl sulfonyl hydrazides to afford tetra- or trisubstituted sulfonated pyrazoles in moderate to good yields, respectively. The gram-scale electrochemical transformation demonstrated the efficiency and practicability of this synthetic strategy. In addition, the sulfonated NH-pyrazole can be obtained via the dissociation of the N-tosyl group. Mechanistic studies reveal that the electrochemical cascade reaction synthesis of polysubstituted sulfonated pyrazoles proceeded via the sequence of intermolecular condensation, radical–radical cross coupling sulfonylation, and pyrazole annulation.

A facile and efficient strategy for the synthesis of 1,4-dihydropyridazines and pyridazines through I2-promoted [4+2] cycloaddition of hydrazones with enaminones has been developed. The switch in selectivity is attributed to...

Given the unique properties of sewage sludgederived carbonaceous materials (SC) and the correlation of SC with recycling sewage sludge in an efficiently safe way, there is significant attraction from researchers to develop innovative methodologies that enable a more extensive application of SC. Applying SC in forming rather than cleaving chemical bonds is highly desirable to maximize the value of sewage sludge. Here, we report the surface-modified SC-catalyzed N−H insertion reaction of a wide range of α-aryl diazoesters with amines, which was first accomplished with moderate to good yield (86%). The catalytic performance of this catalyst is shown by a 10 gram-scale reaction and the synthesis of a drug molecule, (±)-clopidogrel. A mechanistic study suggests that the C−N bond formation involves ammonium ylide intermediates and hydrogen bonding. This discovery leads to the realization of a feasible strategy for sewage sludge recycling and a new avenue to catalyst research.