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Benzopyrans

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


Papers
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Journal ArticleDOI
TL;DR: In this article, the synthesis of substituted 7,7-diphenyl-7H-pyrano[3,2-e]benzazoles 2a-f and 7, 7-Diphenymethyl-7 H-Pyrano [2,3-g]benzmanazoles 4a-d is described.
Abstract: The synthesis of substituted 7,7-diphenyl-7H-pyrano[3,2-e]benzazoles 2a-f and 7,7-diphenyl-7H-pyrano[2,3-g]benzazoles 4a-d is described. Thus, suitable titanium(IV) phenolates reacted with β-phenylcinnamaldehyde in refluxing aprotic non-polar solvents. Electrocyclisation of o-quinone allides generated in situ gives regiospecifically the title compounds. Stoichiometric amounts of heterocyclic phenol, titanium tetraethoxide and the carbonyl compound, have been found to give better results. In this series, substitution on the α position leads to the formation of the regioisomer. The method could be also extended to the formation of 8,8-diphenyl-8H-pyrano[2,3-e]benzazole 8. A side reaction between the desired pyran and a second molecule of heterocyclic phenol was observed. This condensation product 9 was isolated and characterized in the case of the imidazole derivative, and a mechanism for its formation is proposed.

29 citations

Journal ArticleDOI
TL;DR: In this article, a successful Claisen rearrangement of a number of 1,4-diaryloxy-2-butynes is reported, which offers a facile synthetic route to tetracyclic derivatives resembling the naturally occurring pterocarpans.

29 citations

Patent
23 Feb 2001
TL;DR: In this article, photochromic hydroxylated/carboxylated naphthopyran compounds are described, examples of which are certain 2H-naphtho[1,2-b]pyrans, 3H-Naphthohopyrans and indeno[2,1-f]naphthsopyrants each having at least one hydroxynylated or carboxylated substituent.
Abstract: Described are novel photochromic hydroxylated/carboxylated naphthopyran compounds, examples of which are certain 2H-naphtho[1,2-b]pyrans, 3H-naphtho[2,1-b]pyrans and indeno[2,1-f]naphtho[1,2-b]pyrans each having at least one hydroxylated/carboxylated substituent. Specific substituents are also present on the naphtho, indeno and/or pyrano portions of the compounds. These compounds may be represented by the graphic formulae (I), (II) and (III). Also described are various substrates, e.g., paper, glass, polymeric organic materials, etc., that contain or that are coated with such compounds. Optically clear articles such as contact lenses or other plastic transparencies that incorporate the novel naphthopyran compounds or combinations thereof with complementary photochromic compounds, e.g., certain other naphthopyrans, indenonaphthopyrans, benzopyrans, oxazine-type compounds, etc., are also described.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a novel intramolecular cyclisation reaction between an organocobalt stabilised cation and a trisubstituted alkene was accomplished to afford a new family of benzopyran derivatives.

28 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
20229
20214
20203
20192
20186