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Topic

Benzopyrans

About: Benzopyrans is a(n) research topic. Over the lifetime, 694 publication(s) have been published within this topic receiving 8830 citation(s).


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Patent
13 Oct 1995
Abstract: Described are novel photochromic indeno-fused naphthopyran compounds, examples of which are naphthopyran compounds having a substituted or unsubstituted indeno group, the 2,1 positions of which are fused to the f side of the naphtho portion of the naphthopyran, and certain substituents at the 3-position of the pyran ring. Certain substituents may also be present at the number 5, 6, 7, 8, 9, 10, 11, 12, or 13 carbon atoms of the compounds. These compounds may be represented by the following graphic formula: ##STR1## Also described are polymeric organic host materials that contain or that are coated with such compounds. Optically clear articles such as ophthalmic lenses or other plastic transparencies that incorporate the novel naphthopyran compounds or combinations thereof with complementary photochromic compounds, e.g., certain other naphthopyrans, benzopyrans, and spiro(indoline)type compounds, are also described.

170 citations

Journal ArticleDOI
Abstract: Chromenes (benzopyrans) and benzofurans are characteristic natural products of certain tribes of the Asteraceae. This review highlights recent findings

147 citations

Patent
19 Nov 1996
Abstract: Described are novel reversible photochromic naphthopyran compounds, examples of which are 3H-naphtho[2,1-b]pyrans having an acyl or aroyl oxy-bearing substituent at the number 6 carbon atom and certain substituents at the 3-position of the pyran ring. Certain substituents may also be present at the number 5, 7, 8, 9 or 10 carbon atom of the naphthopyran. These compounds may be represented by graphic formula (I). Also described are polymeric organic host materials that contain or that are coated with such compounds. Optically clear articles such as ophthalmic lenses or other plastic transparencies that incorporate the novel naphthopyran compounds or combinations thereof with complementary photochromic compounds, e.g., certain other naphthopyrans, benzopyrans, and spiro(indoline) type compounds, are also described.

142 citations

Journal ArticleDOI
TL;DR: The first transition metal catalyzed asymmetric carboalkoxylation reaction of propargyl esters is described and experimental evidence supports a mechanism proceeding via the generation of a stabilized carbocation from an allylic oxonium intermediate and subsequent trapping by a chiral allylgold(I) spieces.
Abstract: The first transition metal catalyzed asymmetric carboalkoxylation reaction of propargyl esters is described. The (R)-MeO-DTBM-BIPHEP(AuCl)2-catalyzed reactions allow for the construction of benzopyrans containing quaternary stereocenters with excellent enantioselectivity. Experimental evidence supports a mechanism proceeding via the generation of a stabilized carbocation from an allylic oxonium intermediate and subsequent trapping by a chiral allylgold(I) spieces.

141 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20213
20203
20192
20186
20175
201613