Topic
Benzopyran
About: Benzopyran is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 15235 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: A Trolox analogue, 3,4-dihydro-2-ethoxycarbonyl-6-methoxy-7-hydroxy- benzopyran and Precocene II, were prepared from substituted α-methylene-δ- valerolactone and 1,1-bis-(methylthio)-2-propanone or butanone, via a 1,3-Michael- Claisen annulation as discussed by the authors.
18 citations
18 citations
TL;DR: A new route to biologically active benzopyrans was developed via an intramolecular cyclisation and cis diol formation as discussed by the authors, which can be used to obtain a new class of biologically active benopyran.
18 citations
TL;DR: In this paper, thermal thio-Claisen rearrangement of 4-allylthio[1]benzopyran-2-ones in refluxing quinoline for 0.5-8.0 h was performed.
Abstract: A number of thieno[3,2-c][1]benzopyran-4-ones, potential antiinflamatory, antipyretic, and antiallergic drugs, are synthesized in 65–80% yield by thermal thio-Claisen rearrangement of 4-allylthio[1]benzopyran-2-ones in refluxing quinoline for 0.5–8.0 h. The 4-allylthio[1]benzopyran-2-ones are in turn prepared in 75–85% yield from 4-mercaptocoumarin and different allylic halides by phase-transfer-catalysed alkylation with TBAB or BTEAC catalyst in chloroform-aq. NaOH at room temperature.
18 citations
TL;DR: The observed diastereoselectivity during O-stannyl ketyl radical cyclization is influenced by aromatic substitution ortho to the aldehyde, whilst acyl radicalcyclization followed by stereoselective reduction of the resulting pyranones provides a complimentary approach to forming the required γ-lactone-fused benzopyran systems.
Abstract: The synthesis of a series of γ-lactone-fused benzopyrans and benzofurans, analogues of the pyranonaphthoquinone antibiotics, is reported. Preparation of the heterocycles was achieved by either O-stannyl ketyl or acyl radical cyclization of benzaldehyde precursors followed by oxidation to give the pyrano- and furanobenzoquinone systems. The observed diastereoselectivity during O-stannyl ketyl radical cyclization is influenced by aromatic substitution ortho to the aldehyde, whilst acyl radical cyclization followed by stereoselective reduction of the resulting pyranones provides a complimentary approach to forming the required γ-lactone-fused benzopyran systems.
18 citations