Enzymatic cyclizations using laccases: Multiple bond formation between dihydroxybenzoic acid derivatives and aromatic amines

Amine‐Functionalized Amino Acid‐based Ionic Liquids as Efficient and High‐Capacity Absorbents for CO2

“…In standard methods for the synthesis of benzimidazole derivatives, the condensation of an ortho ‐phenylenediamine ( 72 ) with an aromatic aldehyde was conducted in the presence of inorganic oxidants. To produce benzimidazole derivatives, Leutbecher et al 140. developed a laccase‐catalyzed domino reaction, in which aerial oxygen was used as oxidant in buffer (pH 6.0) under very mild reaction conditions (Scheme ).…”

A Sustainable Synthesis of Asymmetric Phenazines and Phenoxazinones Mediated by CotA‐Laccase

“…They oxidize, in aqueous medium, a range of different substrates including aromatic amines, but the vast majority of synthetic reactions reported involve radical‐coupling reactions of phenolic monomers and cross‐coupling reactions of substituted catechols and hydroquinones with nitrogen based and carbon derived nucleophiles via in situ generated ortho ‐ and para ‐quinones. Concerning the laccase oxidation of aromatic amines and further radical‐coupling reactions involving the generated ortho and para ‐benzodiimine or benzoquinoneimine intermediates, few reports were found …”

Laccase-mediated multi-step homo- and heteromolecular reactions of ortho -dihydroxylated aromatic compounds and mono- or diaminated substances resulting in C C, C O and C N bonds

“…Thus, the cyclization -and not the 1,4-addition forming a dimer as described for products 4a-l -is essential for the formation of a stable product. We described previously [26] the reaction of para-dihydroxylated benzoic acid derivatives with 3c,d resulting in cyclization after 1,4-addition of the azole and subsequent intramolecular 1,2-addition forming cycloheptenes (diazepines) or addition-elimination-reaction forming cyclooctenes (diazocines).…”

“…Recently, we used laccase to produce additional heterocycles including cycloheptenes (diazepines), cyclooctenes (diazocines), diazaspiro cyclohexenes, and phenazines using paradihydroxybenzoic acid derivatives and aromatic or heteroaromatic amines [26].…”