Synthesis and photochemical reactivity of new 4-substituted naphtho[1,2-b]pyran derivatives
作者:Céu M. Sousa、Paulo J. Coelho、Gaston Vermeersch、Jérôme Berthet、Stephanie Delbaere
DOI:10.1016/j.jphotochem.2010.09.009
日期:2010.11
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
一种新的萘并[1,2- b具有在4位酯取代基〕吡喃从2,3-二氢-2,2-二苯基-4-制备ħ -萘并[1,2- b ]吡喃-4-酮和然后转化为羧酸衍生物。通过紫外可见光谱研究了这两种化合物的光致变色行为,并通过NMR阐明了光产物的结构。在紫外线照射下,未着色的酯衍生物可提供具有反式-反式的单色着色的光异构体(TT)构型,同时将酸不可逆地转化为降解产物。在强酸介质中,两种化合物都转化为吡喃环开口形成的螺环衍生物,随后形成分子内内酯环并进行亲电芳族取代。