64945-06-8Relevant articles and documents
A simple, enaminone-based approach to some bicyclic pyridazinium tetrafluoroborates
Josefik, Frantisek,Svobodova, Marketa,Bertolasi, Valerio,Simunek, Petr
, p. 1463 - 1471 (2013)
Easily obtainable cyclic enaminones (piperidin-2-ylidenealkanones) can be transformed into substituted bicyclic pyridazinium tetrafluoroborates upon treatment with corresponding diazonium salts. The transformation can be performed either in a one-pot way or in a two-step process with the isolation of single azo-coupled enaminone as the intermediate. The former method is superior. Under the optimized conditions, a number of pyridazinium salts substituted with both electron-donating and electron-withdrawing substituents was easily synthesized. A mechanism of the formation of the pyridazinium salts is suggested. A partial drawback is the possibility of the formation of a mixture of products when using a different diazonium salt in each step due to a reversibility of the azo coupling. This can be suppressed by using a more reactive diazonium salt before a less reactive one.
A new bicyclic oxazaborines with a bridged nitrogen atom, their thermic rearrangement and fluorescence properties
Josefík, Franti?ek,Svobodová, Markéta,Bertolasi, Valerio,?im?nek, Petr,MacHá?ek, Vladimír,Almonasy, Numan,?erno?ková, Eva
, p. 75 - 81 (2012/02/16)
Cyclic β-enaminones bearing secondary amino group react with 4-substituted benzenediazonium tetraphenylborates in dichloromethane to form substituted bicyclic [1,3,2λ4]oxazaborines The oxazaborines rearrange, on heating to 200 °C in the absence of solvent or in DMF or DMSO, to isomeric 2H-[1,2,4,3λ4]triazaborines. Previously prepared [1,3,2λ4]oxazaborines derived from acyclic β-enaminones bearing secondary amino group either did not undergo the rearrangement or with a lot of difficulties and with negligible yield. The fluorescence behaviour of the prepared triazaborines was observed. These compounds fluoresce in 2-methyltetrahydrofurane and in solid state under low temperatures.
Boric acid: a new regiospecific decarboxylating agent. Syntheses of cyclic imines, β-enaminones, and β-enaminodiketones from β-enaminoesters
Delbecq, Philippe,Bacos, Daniel,Celerier, Jean Pierre,Lhommet, Gerard
, p. 1201 - 1206 (2007/10/02)
The synthesis of cyclic imines 2, β-enaminones 6, and β-enaminodiketones 7 is described.Regio- and stereospecific thermolysis of β-enaminoesters 4 with boric acid permit these preparations in generally good yields. Key words: boric acid, cyclic β-enaminoesters, decarboxylation, cyclic imines, cyclic β-enaminones.