A highly efficient palladium-catalyzed arylation of azoles at the C2-position using 1-aryltriazenes as aryl reagents was developed. Azoles including oxazoles, thiazoles, imidazoles, 1,3,4-oxadiazoles, and oxazolines could react with 1-aryltriazenes smoothly to generate the corresponding products in good to excellent yields, and various substitution patterns were tolerated toward the reaction.
Transnitrosation by N-Aryl-N-nitrosoureas; NO-Carrying O-Nitrosoisourea.
作者:Masayuki TANNO、Shoko SUEYOSHI、Naoki MIYATA
DOI:10.1248/cpb.42.1760
日期:——
Transfer of nitroso groups, so-called transnitrosation, from aromatic N-nitroso compounds such as N-nitrosoureas, N-nitrosamides and N-nitrosamines, to aromatic amines or ureas was observed under non-acidic conditions at room temperature. Sterically hindered 3, 3-dibenzyl-1-(4-tolyl)-1-nitrosourea (1a) rapidly nitrosates indoline, N-alkylanilines or 3-methyl-1-(4-tolyl)urea to give their N-nitroso derivatives. In the case of N, N-dimethylanilines, nitrosative demethylation occurs to give N-methyl-N-nitrosanilines. The transnitrosation is accelerated by electron-releasing groups on the nitroso acceptors, N-alkylanilines. The transnitrosation mechanism is considered to be as follows : N-nitrosourea (1) thermally decomposes to nitric oxide and ureidyl radical followed by formation of an O-nitrosoisourea intermediate (10), which acts as an NO-carrying agent and nitrosates anilines or ureas.
A practical approach involving decarboxylative arylation of cinnamic acids using aryl triazenes has been developed to accomplish the synthesis of stilbenes. The method employs easily accessible starting materials and features broad substrate scope and functional group tolerance.
Efficient conversion of 1-aryl-3, 3-dialkyltriazenes to phenols and oxygen-18 labeled phenols
作者:N. Satyamurthy、Jorge R. Barrio、Gerald T. Bida、Michael E. Phelps
DOI:10.1016/s0040-4039(00)97634-2
日期:1990.1
Phenols have been synthesized in excellent yields using a cationexchangeresin (H+ form) assisteddecomposition of 1-aryl-3,3-dialkyltriazanes in the presence of water. This method is also amenable to a high yield and high enrichment synthesis of oxygen-17 and 18 labeled phenols.