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Synthesis and photochemical reactivity of new 4-substituted naphtho[1,2-b]pyran derivatives

Paper ID Volume ID Publish Year Pages File Format Full-Text
28859 44097 2010 6 PDF Available
Title
Synthesis and photochemical reactivity of new 4-substituted naphtho[1,2-b]pyran derivatives
Abstract

A new naphtho[1,2-b]pyran possessing an ester substituent in position 4 was prepared from 2,3-dihydro-2,2-diphenyl-4H-naphtho[1,2-b]pyran-4-one and then converted to the carboxylic acid derivative. The photochromic behaviour of these two compounds was studied by UV–vis spectroscopy and the structures of the photoproducts elucidated by NMR. Under UV irradiation the uncoloured ester derivative afforded a single coloured photoisomer having a transoid-trans (TT) configuration while the acid was irreversibly transformed into degradation products. In strong acid medium both compounds were converted to a spiro derivative formed through the opening of the pyran ring followed by an intramolecular lactone ring formation and electrophilic aromatic substitution.

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Keywords
Photochromism; Naphthopyran; NMR; Lactone; Triflic acid; UV irradiation; Mukaiyama aldol condensation
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Synthesis and photochemical reactivity of new 4-substituted naphtho[1,2-b]pyran derivatives
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 216, Issue 1, 15 November 2010, Pages 73–78
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
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Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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