Z-Selective synthesis of o-bromoacetophenone N-tosylhydrazones and formation of 3-methylindazoles in aqueous ethanol

Copper(I) salt/PEG‐400 catalysis in one‐pot direct synthesis of 1‐aryl‐1H‐indazoles from 2‐bromobenzaldehydes and arylhydrazines

“…Here again, phenylhydrazine hydrochloride also could be used in place of phenylhydrazine without any loss of the yield of 3a under CuI/Cs 2 CO 3 and CuBr/NaO t Bu (entries 9 and 10). Among the solvents examined under the employment of CuI and NaO t Bu, PEG-400 in terms of product 3a yield and complete conversion of 1a was shown to be the solvent of choice (entries [11][12][13]. This result indicates that PEG-400 plays a pivotal role in the present reaction.…”

“…We reported on the one‐pot direct procedure for 1‐aryl‐1 H ‐indazoles from 2‐bromobenzaldehydes and arylhydrazines in the presence of a palladium catalyst combined with a phosphorus chelating ligand . It was also disclosed that several copper salts in combination with a ligand can be used to catalyze such an intramolecular amination of arylhydrazones of o ‐halo aromatic carbonyl compounds leading to 1‐aryl‐1 H ‐indazoles . Ding et al .…”

“…[11] It was also disclosed that several copper salts in combination with a ligand can be used to catalyze such an intramolecular amination of arylhydrazones of o-halo aromatic carbonyl compounds leading to 1-aryl-1H-indazoles. [12][13][14][15] Ding et al recently reported on a ligand-free CuI-catalyzed two-step synthesis of 1-aryl-1H-indazoles from o-halo aromatic carbonyl compounds and arylhydrazines. [16] Under these circumstances, this report describes an efficient ligand-free copper salt-catalyzed one-pot procedure in PEG-400 for the synthesis of 1-aryl-1H-indazoles from 2-bromobenzaldehydes and arylhydrazines (or their hydrochlorides).…”

3‐Substituted Indazoles as Configurationally Locked 4EGI‐1 Mimetics and Inhibitors of the eIF4E/eIF4G Interaction

“…Our arylhydrazones 7 required a combination of base (Na 2 CO 3 / N , N ’-dimethylethylenediamine) and CuI used as a catalyst, which proved to be successful in many N -arylation reactions. [41] This combination afforded synthesis of constrained indazole-based ( E )- 4EGI-1 mimetic library 1 (Scheme 5), in moderate to excellent yields.…”

Targeting the >i<h>/i<TRPV6 with capsaicinoid inhibitors

“…165 It is worth noting that the selective synthesis of Z-sulfonyl hydrazones was already described depending on the reaction conditions and proper aldehyde-substitutions. [176][177][178] Figure 14. Crystal structure of a sulfonylhydrazone revealing its E-antiperiplanar stereochemistry.…”