Homogeneous hydrogenation of electron-deficient alkenes by iridium complexes
作者:Volodymyr Semeniuchenko、Thomas E. Exner、Volodymyr Khilya、Ulrich Groth
DOI:10.1002/aoc.1841
日期:2011.11
The catalytic homogeneoushydrogenation of electron‐deficient alkenes (nucleophilic hydrogenation) was achieved in the presence of iridium complexes and a base as co‐catalyst. Contrary to hydrogenation of electron‐rich alkenes, which is inactivated by bases, the hydrogenation of the electron‐deficient alkenes turned out to be base activated. Here, we present a more thorough study on the capacities
The selectivity of the reactions of 3-(polyfluoroacyl)-4H-chromen-4-ones with a wide range of aminoheterocycles and arylamines has been evaluated. The method described facilitates access to polyfluoroalkyl-containing fused pyridines. aminoheterocycles - arylamines - condensation - chroman-4-ones - polyfluoroalkyl - fused pyridines
6-tris(trifluoromethyl)-1,3,5-triazine, a set of fluorinated pyrazolo[3,4-b]pyridine and pyrazolo[3,4-d]pyrimidine nucleosides was obtained. Synthetic access to stable 4-(polyfluoroalkyl)-4,7-dihydro-1H-pyrazolo[3,4-b]pyridin-4-ole was elaborated, which can be considered to be mimetics of the putative transition state involved in adenosine deaminase activity. pyrazole - pyridine - pyrimidine - fluorine
由5-氨基-1-(2,3-开始ö异亚丙基β- d呋喃核糖基)-1 ħ吡唑,1,3- CCC-,1,3- CNC含氟- dielectrophiles和2,4-获得了6-6-三(三氟甲基)-1,3,5-三嗪,一组氟化的吡唑并[3,4- b ]吡啶和吡唑并[3,4- d ]嘧啶核苷。合成了稳定的4-(多氟烷基)-4,7-二氢-1H-吡唑并[3,4- b ]吡啶-4-酮的合成途径,这可以被认为是腺苷涉及的假定过渡态的模拟物。脱氨酶活性。 吡唑-吡啶-嘧啶-氟-环化-亲电子芳族取代
Reactions of 3-(polyfluoroacyl)chromones with hydroxylamine: synthesis of novel RF-containing isoxazole and chromone derivatives
作者:Vyacheslav Ya. Sosnovskikh、Vladimir S. Moshkin、Mikhail I. Kodess
DOI:10.1016/j.tet.2008.06.041
日期:2008.8
Reaction of 3-(polyfluoroacyl)chromones with hydroxylamine free base proceeds via nucleophilic 1,4-addition followed by opening of the pyrone ring and subsequent cyclization to 4-(polyfluoroalkyl)-4H-chromeno[3,4-d]isoxazol-4-ols in good yields. On treatment with trifluoroacetic acid, the isoxazole ring of this annulated heterocyclic system opens to give 3-cyano-2-(polyfluoroalkyl)chromones, which
3-(多氟酰基)发色酮与羟胺游离碱的反应通过亲核的1,4-加成反应进行,随后打开吡喃环并随后环化为4-(多氟烷基)-4 H-苯并[3,4- d ]异恶唑- 4-醇收率良好。用三氟乙酸处理时,该环状杂环系统的异恶唑环打开,得到3-氰基-2-(聚氟烷基)色酮,将其成功地用浓H 2 SO 4水解,得到3-氨基甲酰基-2-(聚氟烷基)色酮。 。另一方面,用羟胺盐酸盐对3-(聚氟酰基)色酮进行肟化反应是在与R F基团相连的羰基碳原子上或在C-2原子上发生的,从而得到3-R F。C(NOH)-色酮和5-R F -4-水杨酸异恶唑肟。通过简单地在二甲基亚砜中加热,将前者容易地转化为3-R F -4-水杨酸异恶唑。
Tandem synthesis of 4-aminoxanthones is controlled by a water-assisted tautomerization: a general straightforward reaction
作者:Ana Bornadiego、Jesús Díaz、Carlos F. Marcos
DOI:10.1039/c8ob02527d
日期:——
synthetically challenging. Here, we report the synthesis of both aminodihydroxanthones and fully aromatized aminoxanthones by an easy to perform, one-step multicomponent reaction of isocyanides, 3-carbonylchromones and dienophiles. The mechanism of the reaction involves a sequence of a [4 + 1] cycloaddition, iminolactone-aminofuran tautomerization, [4 + 2] cycloaddition, oxygen ring opening and aromatization