Showing papers on "Benzopyrans published in 1983"
TL;DR: Chromenes (benzopyrans) and benzofurans are characteristic natural products of certain tribes of the Asteraceae and a review of recent findings can be found in this article.
158 citations
TL;DR: In this article, photolysis of 4-chloro-3-(N-Aryliminomethyl) (2H)benzopyrans and benzothiopyrans, 1a - g, yielded the respective quinolides 3a-g.
14 citations
TL;DR: In this paper, a convenient route to substituted 2H[1]benzopyrans is described in which trialkylaluminium compounds are added to coumarins or chromones and the resultant Z-2-(3-hydroxy-1-propenyl)phenols are converted by thermal cyclization in the presence of silica gel to 2H
12 citations
TL;DR: In this article, the Oxidative Claisen rearrangement of 3-aryloxymethyl-(2H)-benzopyrans has been shown to yield the normal products.
6 citations
5 citations
Patent•
18 Aug 1983TL;DR: In this paper, 4H-1-Benzopyrans are prepared by reacting an aminomethylphenol with an alkali metal hydroxide or an alkaline earth metal hydride and a 1,3-diketone.
Abstract: 4H-1-Benzopyrans are prepared by reacting an aminomethylphenol with an alkali metal hydroxide or an alkaline earth metal hydroxide and a 1,3-diketone. The products are useful as antioxidants.
2 citations
TL;DR: In this paper, a mechanism involving reaction of the alkyl-aluminium with the quinone methanide, which is in equilibrium with the pyran (1), is in accord with all experimental results.
Abstract: 2H-1-Benzopyrans react with trialkylaluminium compounds by alkyl- and hydrogen-transfer to C-2 and C-4 to give the o-allylphenols (2), (3), and the (E)-o-propenylphenols (4) and (5). The site of attack and the ratio of alkyl- to hydrogen-transfer depend on the alkylaluminium used and on the size of the substituent at C-2 of the pyran. A mechanism involving reaction of the alkylaluminium with the quinone methanide (6), which is in equilibrium with the pyran (1), is in accord with all experimental results.
1 citations
Patent•
05 May 1983TL;DR: In this article, the authors proposed novel analogues of khellin, which are 5H-furo[3,2-g]benzopyran-5-ones substituted at the 4 and 9 positions by methoxy or optionally substituted by hydroxy or alkoxy groups other than methoxy.
Abstract: Novel analogues of khellin, which are 5H-furo[3,2-g]benzopyran-5-ones substituted at the 4 and 9-positions by methoxy or optionally substituted at the 4-position by hydroxy or alkoxy groups other than methoxy, certain 7-(N,N-dialkylamino)ethen-2-yl substituted compounds, and 7H-furo[3,2-g] [1]benzopyrans, can have anti-atherosclerotic utility.