کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
28859 44097 2010 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Synthesis and photochemical reactivity of new 4-substituted naphtho[1,2-b]pyran derivatives
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
Synthesis and photochemical reactivity of new 4-substituted naphtho[1,2-b]pyran derivatives
چکیده انگلیسی

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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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 216, Issue 1, 15 November 2010, Pages 73–78
نویسندگان
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