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: DBU-catalyzed reactions of salicylic aldehydes with 3-methylpenta-3,4-dien-2-one, 3-benzylpenta/3-4- dienoate gave the corresponding functionalized 2H-1-chromenes in good to excellent yields and good diastereoselectivities in some cases in DMSO, respectively.
113 citations
TL;DR: The first organocatalyzed asymmetric synthesis of chiral benzopyrans was reported in this article, where a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes was performed.
Abstract: Benzopyrans, or chromenes, are widespread in nature and are considered to be a privileged scaffold in medicinal chemistry. Herein, we report the first organocatalyzed asymmetric synthesis of chiral benzopyrans. The benzopyran unit is constructed through a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes, activated through iminium-ion formation with the organocatalyst, followed by an intramolecular aldol reaction and subsequent elimination of water. This overall reaction sequence provides benzopyrans with aromatic C-2 substituents in up to 60% yield and 60% enantioselectivity, while C-2 aliphatic analogues can be obtained in 90% enantiomeric excess, but with only 20% yield. The role of additives, as well as the possible racemization of the benzopyran, was also investigated.
112 citations
Patent•
15 Oct 1999TL;DR: In this article, a class of benzopyrans, benzothiopyrans and dihydroquinolines, dihydronaphthalenes, and analogs thereof, are described for use in treating cyclooxygenase-2 mediated disorders.
Abstract: A class of benzopyrans, benzothiopyrans, dihydroquinolines, dihydronaphthalenes, and analogs thereof, is described for use in treating cyclooxygenase-2 mediated disorders. Compounds of particular interest are defined by Formula (I') wherein X, A?1, A2, A3, A4?, R, R'', R?1 and R2? are as described in the specification.
109 citations
Patent•
06 Sep 2000TL;DR: In this article, photochromic indeno-fused naphthopyran compounds have been described, which have a rating of at least 80 in the Relative ΔOD at Saturation Test and may be represented by the following graphic formula:
Abstract: Described are novel photochromic indeno-fused naphthopyran compounds, examples of which include naphthopyran compounds having a substituted or unsubstituted indeno group, the 2,1 positions of which are fused to the naphtho portion of the naphthopyran as shown below. Also present on the naphthopyran are moderate to strong electron donor substituents at the number 6- and 7-positions and optionally at the 8-position of the pyran ring or a cyclic group fused to the h side of the naphtho portion and weak to moderate electron donor substiuents at the 3-position of the pyran ring. Certain substituents may also be present at the number 5, 8, 9, 10, 11, 12, or 13 carbon atoms of the compounds. These compounds have a rating of at least 80 in the Relative ΔOD at Saturation Test and may be represented by the following graphic formula: 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.
105 citations
TL;DR: A new recyclable temperature-dependant phase-separation system comprised of PEG-1000-based dicationic acidic ionic liquid and toluene was developed and used in one-pot three-component condensation to prepare benzopyrans in excellent yields.
102 citations