A novel electrochemical conversion of CO 2 with aryl hydrazines and paraformaldehyde into 1,3,4-oxadiazol-2(3 H )-one derivatives in one step

A Multicomponent Electrosynthesis of 1,5-Disubstituted and 1-Aryl 1,2,4-Triazoles

“…On the basis of the above experiments and the previous investigations, − a plausible reaction mechanism was outlined in Scheme . Initially, I – ions are electro-oxidized at the anode to form a reactive iodide radical or I 2 . , At the same time, phenylhydrazine easily reacts with paraformaldehyde to produce intermediate 1-methylene-2-phenylhydrazine 2a . In the presence of a strong base, 2a can generate 1-methylene-2-phenylhydrazine anion A , , followed by the electrochemical oxidation to yield a radical B , which is supported by the CV experiments.…”

“…For example, NaOH and t -BuOK afforded the target product 3a in higher yields than weak bases (Table , entries 12–15). According to our experience, I 2 electrogenerated in situ at an anode could promote some transformations effectively . In the absence of any iodides, only a trace amount of 3a was observed (Table , entry 16), indirectly indicating that reactive iodine electrogenerated in situ could promote this transformation as well.…”

“…On the basis of the above experiments and the previous investigations, − a plausible reaction mechanism was outlined in Scheme . Initially, I – ions are electro-oxidized at the anode to form a reactive iodide radical or I 2 . , At the same time, phenylhydrazine easily reacts with paraformaldehyde to produce intermediate 1-methylene-2-phenylhydrazine 2a .…”

“…Among various electrochemical strategies, reactive iodide radical or iodine electrogenerated in situ at an anode could effectively induce or catalyze some transformations, which seems to be attractive. With the help of I 2 electrogenerated in situ at a graphite anode, our group has also achieved the electrochemical conversion of CO 2 with olefins or aryl hydrazines and paraformaldehyde . These successful electrosynthetic examples motivate us to develop a new electrochemical route for the synthesis of substituted 1,2,4-triazoles under mild conditions.…”

A Three-Phase Four-Component Coupling Reaction: Selective Synthesis of o-Chloro Benzoates by KCl, Arynes, CO2, and Chloroalkanes

“…However, the use of expensive transition-metal catalysts and highly reactive reagents has limited their applications to some extent. Therefore, based on the above observations and our previous reports about CO 2 , we envisioned that the reaction might proceed by employing KCl as anionic nucleophiles and using CO 2 as the source of ester to access o -chloro benzoate derivatives.…”