Benzopyrans

About: Benzopyrans is a research topic. Over the lifetime, 694 publications have been published within this topic receiving 8830 citations.

Photochemical studies on 3,4-epoxy-3,4-dihydro-2H-1-benzopyrans

Abstract: Photochemical behaviour of 3,4-epoxy-3,4-dihydro-2H-1-benzopyrans, intermediates in the synthesis of pterocarpans, has been studied in various solvents. While ring contraction leading to 2,3-dihydrobenzofurans through a photodecarbonylation process was observed in cyclohexane, photoisomerisation leading to 3-chromanones was observed in acetone. This study has also been extended to antijuvenile hormone precocene(I) oxide.

Facile Solvent‐Free One‐Pot Synthesis of Pyranobenzopyrans and Their Derivatives.

Abstract: The condensation of hydroxyl coumarins in a facile one-pot procedure with active methylene esters to afford novel benzopyrans under solventless conditions is described. The products underwent further condensation and cyclization reactions to form novel heterocycles.

Environment-Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Triflate Catalyzed Synthesis of Substituted 3,4-Dihydro-2H-1-benzopyrans.

Abstract: A highly catalytic method for the synthesis of dihydrobenzopyrans from salicylaldehydes has been developed. An extension of this method to the synthesis of a pyrano[2,3, b ]benzopyran has also been achieved. Bi(OTf) 3 · x H 2 O (1 x H -1-benzopyrans as a mixture of diastereomers (9:1) in moderate yields. The relative configuration of the methoxy groups in the two diastereomers was established by NOE experiments. The advantages of this method include the use of an easy to handle, inexpensive and relatively non-toxic catalyst.