Barium nitrate catalyzed one pot synthesis of 1,4-dihydropyridines under solvent free conditions at room temperature
作者:Mukul Sharma、Nisha Agarwal、Diwan S. Rawat
DOI:10.1002/jhet.5570450316
日期:2008.5
Bariumnitrate acts as an efficient catalyst for the three-component onepotsynthesis of 1,4-dihydropyridines. Bariumnitrate is a safe chemical, and reaction without the use of organic solvents makes the process eco-friendly.
used as substrates to obtain chiral Hantzsch-type 1,4-DHPs, which are frequently contained in pharmaceuticals. The inert C−H bond was converted into a versatile C−Br bond, which enabled the modification of the chiral 1,4-DHP derivatives with high efficiency by nucleophilic substitution. Furthermore, axially chiral 4-aryl pyridines were accessible by central-to-axial chirality conversion.
Synthesis of pyridinium salts from N-substituted dihydropyridines with BF3OEt2 in the absence of added oxidants
作者:Lais D. Guanaes、Diogo R.B. Ducatti、M. Eugênia R. Duarte、Sandra M.W. Barreira、Miguel D. Noseda、Alan G. Gonçalves
DOI:10.1016/j.tetlet.2015.02.119
日期:2015.4
BF3OEt2 as aromatization promoter in reactions that could be conducted without the need of the usually added oxidizing agents, such as quinones, nitrates, peroxides, and chromates. An optimization study employing an N-phenyl Hantzschester dihydropyridine (1a) to obtain the corresponding N-phenylpyridinium-containing ammonium quaternary salt (2a) was conducted to define the best conditions for the aromatization