A Ceric Ammonium Nitrate N-Dearylation of <i>N</i>-<i>p</i>-Anisylazoles Applied to Pyrazole, Triazole, Tetrazole, and Pentazole Rings: Release of Parent Azoles. Generation of Unstable Pentazole, HN<sub>5</sub>/N<sub>5</sub><sup>-</sup>, in Solution
作者:Richard N. Butler、John M. Hanniffy、John C. Stephens、Luke A. Burke
DOI:10.1021/jo702423z
日期:2008.2.1
pentazole ring. The unstable HN5/N5- produced at −40 °C did not build up in the solution but degraded to azide ion and nitrogen gas with a short lifetime. The 15N-labeling of the N3- ion obtained from all samples proved unequivocally that it came from the degradation of HN5 (tautomeric forms) and/or its anion N5- in the solution.
Transition Metal, Azide, and Oxidant-Free Homo- and Heterocoupling of Ambiphilic Tosylhydrazones to the Regioselective Triazoles and Pyrazoles
作者:Subhankar Panda、Pradip Maity、Debasis Manna
DOI:10.1021/acs.orglett.7b00313
日期:2017.4.7
cyclization reaction of two identical or different tosylhydrazones has been developed to access various 4,5-disubstituted-2H-triazoles under transition metal, azide, and oxidant-free conditions. A mechanistic rationalization study led to the identification of several electronically diverse unsaturated systems for regioselective synthesis of 1- and 2-substituted 1,2,3-triazoles and pyrazoles.
Potassium tert-Butoxide Promoted Synthesis of 4,5-Diaryl-2H-1,2,3-triazoles from Tosylhydrazones and Nitriles
作者:Luyong Wu、Shanguang Qiu、Yuxue Chen、Xinming Song、Li Liu、Xi Liu
DOI:10.1055/s-0040-1707321
日期:2021.1
Intermolecular cycloaddition of tosylhydrazones with nitriles was investigated. t-BuOK was shown to be an excellent base for increasing the effectiveness of the reaction in this protocol, and homocoupling of the tosylhydrazones was significantly inhibited by using xylene as a solvent. Through this transformation, a variety of 4,5-diaryl-2H-1,2,3-triazoles were prepared in good to excellent yields and
Pd(OAc)(2)-catalyzed regioselective C(5)-H arylation of 1,4-disubstituted 1,2,3-triazoles was achieved without ligand under microwave conditions in 1h, generating 1,4,5-trisubstituted 1,2,3-triazoles with good to excellent yields. The obtained molecules can be easily converted into 4,5-disubstituted 1,2,3-triazoles through the debenzylation process with one-pot manipulation.[GRAPHICS].