Topic
Benzopyran
About: Benzopyran is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 15235 citations.
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TL;DR: In this paper, an x-ray diffraction structural analysis of photochromic 1'-3',3'-trimethyl-6-nitro-8bromospiro (4-azaindoline-2,2'-t2H-l]benzopyran) showed that the Cspiro-O bond cleaved upon photoexcitation is elongated and weakened.
Abstract: An x-ray diffraction structural analysis of photochromic 1'-3',3'-trimethyl-6-nitro-8-bromospiro (4-azaindoline-2,2'-t2H-l]benzopyran) showed that azaindoline and indoline spiropryans have similar structures, in which the Cspiro-O bond cleaved upon photoexcitation is elongated and weakened.
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Patent•
06 Jun 2012
TL;DR: The Xyloketals compounds are generated by using phloroglucinol as raw materials and absolute methanol as a solvent and comprising the steps of adding anhydrous magnesium sulfate, reacting with methyl vinyl ketone under the mediation of lewis acid to generate benzopyran cycloether, separating methanolis acid from the benzocycloenol ether, ketalizing and finally cyclizing the radical as discussed by the authors.
Abstract: The invention discloses a synthetic method of Xyloketals compounds, which comprises the steps of: 1, synthesizing chroman; 2, protecting phenolichydroxyl of the chroman; 3, generating chromene; 4, generating ketal; and 5, cyclizing radical The Xyloketals compounds are generated by using phloroglucinol as raw materials and absolute methanol as a solvent and comprising the steps of adding anhydrous magnesium sulfate, reacting with methyl vinyl ketone under the mediation of lewis acid to generate benzopyran cycloether, separating methanol from the benzopyran cycloether to generate benzocycloenol ether, ketalizing and finally cyclizing the radical The invention has simple process, easy purification of the Xyloketals compounds, high purity, low production cost and suitability for industrialized production The synthetic method can realize quantitative conversion, and the Xyloketals compounds can be used for the next reaction without being purified The invention synthesizes the Xyloketals B with the total yield of 3868 percent
1 citations
TL;DR: In this paper, 5-hydroxy uracils and 4-hydroxynodes were refluxed with 2-bromobenzyl bromides in acetone in the presence of anhydrous potassium carbonate to afford a number of 5-(2′)-bromogenyloxy) pyrimidine-2,4-dione (80−92%) or 4-(2´bromomethoxy) benzopyran-7-ones (70−82%) respectively.
Abstract: 5-Hydroxy uracils or 4-hydroxy[1]benzopyran-2-ones were refluxed with 2-bromobenzyl bromides in acetone in the presence of anhydrous potassium carbonate to afford a number of 5-(2′-bromobenzyloxy) pyrimidine-2,4-dione (80–92%) or 4-(2′-bromobenzyloxy) benzopyran-7-ones (70–82%) respectively. These were then refluxed with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of a catalytic amount of azobisisobutyronitrile (AIBN) for 3–4 h to give 1H,3H,6H [2]benzopyrano[4,3-d]pyrimidine-2,4-diones (75–85%) or 12H-benzopyrano[3,2-c][1]benzopyran-5-ones (70–85%) respectively.
1 citations