Construction of trisubstituted chromone skeletons carrying electron-withdrawing groups via PhIO-mediated dehydrogenation and its application to the synthesis of frutinone A
作者:Qiao Li、Chen Zhuang、Donghua Wang、Wei Zhang、Rongxuan Jia、Fengxia Sun、Yilin Zhang、Yunfei Du
DOI:10.3762/bjoc.15.291
日期:——
The construction of the biologically interesting chromone skeleton was realized by PhIO-mediated dehydrogenation of chromanones under mild conditions. Interestingly, this method also found application in the synthesis of the naturally occurring frutinone A.
New 4-oxo-2-vinyl-4H-chromene-3-carbonitrile derivatives have been synthesized by the Knoevenagelreaction of 2-methyl-4-oxo-4H-chromene-3-carbonitrile with aromatic and heteroaromatic aldehydes. Spectral properties of the obtained compounds have been studied.
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。
Bi(OTf)
<sub>3</sub>
‐Mediated (4+1) Annulation of α‐Sulfonyl
<i>o</i>
‐Hydroxyacetophenones with α‐Hydroxy Arylketones to Access Sulfonyl 2‐Aroylbenzofurans
作者:Meng‐Yang Chang、Kuan‐Ting Chen
DOI:10.1002/adsc.202100143
日期:2021.5.18
AbstractIn this paper, a high‐yield, facile route for the scalable synthesis of sulfonyl 2‐aroylbenzofurans via a Bi(OTf)3‐mediated intermolecular double cyclocondensation of α‐sulfonyl o‐hydroxyacetophenones with substituted α‐hydroxy arylketones under mild open‐vessel reaction conditions is described. In the overall reaction, water is generated as the only byproduct. Various metal triflate‐promoted reactions and conditions are investigated for the efficient one‐pot (4+1) annulation reaction.magnified image