Studies in Sulfur Heterocycles.Part 16:Synthesis of [1]Benzothieno[3,2-<i>b</i>]pyrans via Tandem Reactionsfrom 2,3-Dihydrobenzo[<i>b</i>]thiophene-3(2<i>H</i>)ones
作者:Asish De、Sukanta Kamila、Chandrani Mukherjee
DOI:10.1055/s-2003-40825
日期:——
thioaurones derived from cinnamaldehyde, above 200 °C resulted in electrocyclicringclosure and sigmatropic shift in tandem to give substituted [1]benzothieno[3,2-b]pyran. Treatment of N,N-diethyl-2-methylsulfanyl-5-methoxy benzamide and crotonaldehyde gave 4-methyl-8-methoxy[1]benzothieno[3,2-b]pyran via conjugate nucleophilic addition and ringclosure in one pot. Possible mechanistic pathways are discussed
Application of Directed Metallation in Synthesis, Part 2: An Expedient Synthesis of Methoxybenzo[b]thiophenes
作者:Chandrani Mukherjee、Asish De
DOI:10.1055/s-2002-19752
日期:——
A short, simple and expedient synthesis of substituted benzo[b]thiophenes involvingdirected ortho lithiation-side-chain deprotonation-cyclisation-reduction is described. This method is a valuable improvement over earliersyntheses of the same class of compounds, both with respect to the number of steps and overall yields.
Application of directed metalation in synthesis. Part 7: Synthesis of suitably functionalised benzo[b]thiophenes as key intermediates in the synthesis of benzothienopyranones
作者:Tarun Kanti Pradhan、Asish De
DOI:10.1016/j.tetlet.2005.01.038
日期:2005.2
1-(3-hydroxybenzo[b]thiophen-2-yl)ethanone and 1-(3-hydroxybenzo[b]thiophen-2-yl)propan-1-one via an anionic ortho-Fries rearrangement are described. The hydroxy ketones were used as key intermediates in the synthesis of benzothienopyranones.
一锅合成由邻甲基硫烷基芳基N,N-二乙基酰胺与1-(3-羟基苯并[ b ]噻吩-2-基)乙酮和1合成(3-羟基苯并[ b ]噻吩-2-基)芳基甲酮描述了经由阴离子邻-Fries重排的-(3-羟基苯并[ b ]噻吩-2-基)丙-1-酮。羟基酮用作苯并噻吩并吡喃酮合成中的关键中间体。
Application of directed metalation in synthesis. Part 8: Interesting example of chemoselectivity in the synthesis of thioaurones and hydroxy ketones and a novel anionic ortho-Fries rearrangement used as a tool in the synthesis of thienopyranones and thiafluorenones
作者:Tarun Kanti Pradhan、Asish De、Jacques Mortier
DOI:10.1016/j.tet.2005.07.050
日期:2005.9
Chemoselective synthesis of thioaurones or 3-hydroxy benzo[b]thiophen-2-aryl ketones, 1-hydroxy naphtho[2,1-b]thiophen-2aryl ketones and chalcones from N,N-diethyl-ortho-methyl sulfanyl aryl amides were described. (Benzo[b]thiophen-2-yl) alkylates and (naphtho[2, 1-b]thiophen-2-yl) alkylates undergo a novel anionic ortho-Fries rearrangement leading to (3-hydroxy benzo[b]thiophen-2-yl) and (1-hydroxy naphtho[2, 1 -b]thiophen-2-yl) alkyl ketones. The hydroxy ketones were used as intermediates in the synthesis of wide range of benzothienopyranones and thiafluorenones. (c) 2005 Elsevier Ltd. All rights reserved.