Beilstein J. Org. Chem.2020,16, 1820–1829, doi:10.3762/bjoc.16.149
-isomers and of products of the photoinduced rearrangement completed by 1,5-H shift reaction, 3a,4-dihydronaphtho[2,3-c]furans(pyrroles) C, were established based on the data of 1H and 13C NMR spectroscopy and X-ray diffraction studies.
Keywords: benzo[b]thiophene; fulgide; fulgimide; photorearrangement
afford exclusively fulgimides 3Z and 7E, respectively, as the single products (Scheme 2 and Scheme 3).
According to IR, 1H and 13C NMR spectroscopy data Z- and E-isomers of fulgide 3 exist in the form of the open isomers O. This was also confirmed by X-ray diffraction study.
The molecular structures of
fulgides 3Z and 3E are shown in Figure 1 and Figure 2.
Fulgide 3Z possesses Z-configuration at the double bond С(4)=С(5). The 3-methoxy-2-benzo[b]thiophene moiety in 3Z is planar and is almost coplanar with the planar furan-2,5-dione fragment (the dihedral angle is equal to 3.9°). The phenyl rings are
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Graphical Abstract
Scheme 1:
Photoisomerization of 2-benzo[b]thienyl fulgides.
Beilstein J. Org. Chem.2019,15, 2671–2677, doi:10.3762/bjoc.15.260
diamminetetrakis(thiocyanato)chromate(III)), photochromic dyes have been proposed for such a purpose, mainly from the azobenzene, fulgide or diarylethene families [22]. The latter two are particularly attractive for visible light wavelengths above 400 nm. However, their use is conditioned by their availability and
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Graphical Abstract
Figure 1:
Top: photoisomers of diarylethene 1, bottom: spectral overlaps between the 1-o (black line), 1-c (r...