A series of unsaturated carbonyls, quinones, and pyridinium salts have been effectively reduced to the corresponding saturated carbonyls, dihydroxybenzenes, and hydropyridines in moderate to high yields with tetrahydroxydiboron/water as a mild, convenient, and metal-free reduction system. Deuterium-labeling experiments have revealed this protocol to be an exclusive transfer hydrogenation process from
A highly efficient and regioselectivedirectC–H trifluoromethylation of pyridine based on an N-methylpyridine quaternary ammonium activation strategy has been developed. A variety of trifluoromethylpyridines can be obtained in good yield and excellent regioselectivity by treating the pyridinium iodide salts with trifluoroacetic acid in the presence of silver carbonate in N,N-dimethylformamide. The
Imination of<i>N</i>-methylpyridinium salts by liquid ammonia-potassium permanganate. A new synthesis of nudiflorine
作者:D. J. Buurman、H. C. van der Plas
DOI:10.1002/jhet.5570230409
日期:1986.7
Reaction of substituted 1-methyl(benzyl)pyridinium salts (1) with liquidammonia/potassiumpermanganate leads to introduction of the imino group at the carbon adjacent to the nitrogen. The regiospecificity of the reaction strongly depends on substituent X: at C-6 for X = H, CONH2, C6H5 and at C-2 for X = CH3. 3-Aminocarbonyl-1-t-butylpyridinium iodide (5) on treatment with liquidammonia/potassium
取代的1-甲基(苄基)吡啶鎓盐(1)与液态氨/高锰酸钾的反应导致在与氮相邻的碳上引入亚氨基。该反应的区域特异性强烈取决于取代基X:对于C = 6,对于X = H,CONH 2,C 6 H 5,对于C = 2,对于X = CH 3。用液氨/高锰酸钾处理的3-氨基羰基-1-叔丁基碘化碘化物(5)仅得到4-亚氨基化合物8 ; 1 H nmr光谱显示5在液氨中,得到σ-加合物4-氨基-1,4-二氢-和6-氨基-1,6-二氢-3-吡啶甲酰胺的混合物(6和7)。令人惊讶地,在用液态氨/高锰酸钾,1,6-二氢-1-甲基-6-氧代-3-吡啶甲酰胺(14)处理3-氨基羰基-1,6-二甲基吡啶碘化物(13)时观察到了氧十二烷基甲基化反应。被获得。该化合物可以很容易地被三氯氧化磷转化为生物碱nudiflorine(15)。
Synthesis of 2-Formylpyrroles from Pyridinium Iodide Salts
synthesis of 2-formylpyrroles from pyridinium salts is reported. This protocol enables the synthesis of diversely substituted 2-formylpyrroles in good yields under operationally simple conditions. The detailed mechanistic studies reveal that the reaction proceeds via a novel H2O-triggered ring opening of the pyridinium salt and a subsequent intramolecularly nucleophilic addition sequence.
Cation–π interactions secure aggregation induced emission of planar organic luminophores
作者:Kaspars Leduskrasts、Artis Kinens、Edgars Suna
DOI:10.1039/c9cc06829e
日期:——
The use of non-covalent intermolecular π+–π interactions between quaternary pyridinium or imidazolium cations and aromatic π systems is an efficient approach to achieve AIE in planar purely organic luminophores.