Chemistry of Diazafulvenium Methides in the Synthesis of Functionalized Pyrazoles
摘要:
The chemistry of diazafulvenium methides generated by the thermal extrusion of sulfur dioxide from 2,2-dioxo-1H,3H-pyrazolo[1,5-c] [1,3]thiazoles is described. The diazafulvenium methides unsubstituted at C-7 participate in [8 pi + 2 pi] cycloadditions giving pyrazolo-annulated heterocycles resulting from the addition across the 1,7-position. 1-Methyl-diazafulvenium methides and 7,7-dimethyl-diazafulvenium methides undergo intramolecular sigmatropic [1,8]H shifts giving vinyl-1H-pyrazoles.
New chemistry of diazafulvenium methides: one way to pyrazoles
作者:Teresa M.V.D. Pinho e Melo、Maria I.L. Soares、António M.d’A. Rocha Gonsalves
DOI:10.1016/j.tetlet.2005.11.094
日期:2006.1
Diazafulvenium methides generated from the solution pyrolysis of pyrazolo[1,5-c][1,3]thiazole-2,2-dioxides participate in [8π+2π] cycloadditions giving pyrazolo[1,5-a]pyridine derivatives. 1-Methyl-diazafulvenium, generated under flash vacuum pyrolysis reaction conditions, undergoes an intramolecular sigmatropic [1,8]H shift giving 1-vinyl-1H-pyrazoles.
由吡唑并[1,5- c ] [1,3]噻唑-2,2-二氧化物的溶液热解产生的二氮杂富烯基甲基参与[8π+2π]环加成反应,得到吡唑并[1,5- a ]吡啶衍生物。在快速真空热解反应条件下产生的1-甲基二氮富烯鎓发生分子内σ[1,8] H位移,生成1-乙烯基-1 H-吡唑。
Chemistry of Diazafulvenium Methides in the Synthesis of Functionalized Pyrazoles
作者:Teresa M. V. D. Pinho e Melo、Cláudio M. Nunes、Maria I. L. Soares、José A. Paixão、Ana Matos Beja、Manuela Ramos Silva
DOI:10.1021/jo070265x
日期:2007.6.1
The chemistry of diazafulvenium methides generated by the thermal extrusion of sulfur dioxide from 2,2-dioxo-1H,3H-pyrazolo[1,5-c] [1,3]thiazoles is described. The diazafulvenium methides unsubstituted at C-7 participate in [8 pi + 2 pi] cycloadditions giving pyrazolo-annulated heterocycles resulting from the addition across the 1,7-position. 1-Methyl-diazafulvenium methides and 7,7-dimethyl-diazafulvenium methides undergo intramolecular sigmatropic [1,8]H shifts giving vinyl-1H-pyrazoles.