Topic
Benzopyrans
About: Benzopyrans is a research topic. Over the lifetime, 694 publications have been published within this topic receiving 8830 citations.
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TL;DR: An efficient synthesis of 4-alkyl-4-methyl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-dione or 4-aryl-3.4- dihydropyrano-2 H,5 H-p Pyrano via reaction 4-hydroxycoumarin with Meldrum's acid and ketones or aldehydes is described.
Abstract: An efficient synthesis of 4-alkyl-4-methyl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-dione or 4-aryl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-diones via reaction 4-hydroxycoumarin with Meldrum's acid and ketones or aldehydes is described.
5 citations
TL;DR: In this article, the reaction of electron deficient pyrroles and pyrazoles with trans-3-bromo-6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-ol under basic conditions results in the formation of 2-isopropylbenzofurans by a mechanism which appears to be dependent on the rate of the competitive dehydration reaction leading to the corresponding benzopyrans.
5 citations
5 citations
TL;DR: In this paper, a series of photochromic diaryl benzopyrans fused with benzofuran have been prepared and tested for photo-chromic performance, showing bathochromic shifts in the UV and broad bands in the visible spectra.
Abstract: A series of photochromic diaryl benzopyrans fused with benzofuran have been prepared and tested for photochromic performance The four isomeric hydroxydibenzofurans were coupled with (un)substituted 1,1-diphenyl propargyl alcohols The resulting photochromic products show bathochromic shifts in the UV and broad bands in the visible spectra compared to 2,2-diaryl benzopyrans (2,2-diarylchromenes) It has also been found that the position of the benzofuran fusion has a profound effect on the visible spectrum and fade rate In addition to structure-property relationships, the synthesis of these compounds is discussed
5 citations
TL;DR: The title benzopyranones 1−3 gave the benzo[b]furan 7 and the benzos[b]-cyclopropa[e]pyrans 8 and 9 with chloroacetone in acetone containing anhydrous potassium carbonate and a catalytic amount of potassium iodide, respectively, but gave the 1-benzopyrans 10, 11 and 14 in dichloromethane in the presence of Brockman neutral alumina, respectively.
Abstract: The title benzopyranones 1–3 give the benzo[b]furan 7 and the benzo[b]cyclopropa[e]pyrans 8 and 9 with chloroacetone in acetone containing anhydrous potassium carbonate and a catalytic amount of potassium iodide but give the 1-benzopyranones 10, 11 and 14 in dichloromethane in the presence of Brockman neutral alumina, respectively.
5 citations