139118-22-2Relevant articles and documents
The effects of electron donating groups on the photoisomerization of tetrasubstituted 4H-thiopyrans
Pirelahi, Hooshang,Oskooee, Maryam Sadeghi
, p. 403 - 404 (1999)
The relative yields of photoisomerization products of 4,4-and 2,6-dianisyl isomers 1 and 2 were compared with that of the unsubstituted model compound 3 under the identical experimental conditions.
Photochemical Reaction of 2,4,4,6-Tetraaryl-4H-Pyrans and -4H-Thiopyrans with Colour Change by a 1,5-Electrocyclic Reaction. X-Ray Molecular Structure of 4-Methyl-2,3,6-triphenyl-2H-thiopyran
Mori, Yukie,Maeda, Koko
, p. 2061 - 2066 (2007/10/02)
2,4,4,6-Tetraphenyl-4H-pyran and -4H-thiopyran exhibited a photochemical colour change in the solid state.On irradiation in solution, 2,4,4,6-tetraphenyl-4H-pyran gave 1,3,5,6-tetraphenyl-2-oxabicyclohex-3-ene, while the 4H-thiopyran gave 1,3,5,6-tetraphenyl-2-thiabicyclohex-3-ene as an initial photoproduct, followed by further transformation into 2,3,4,6-tetraphenyl-2H-thiopyran. 4-(4-Bromophenyl)-2,4,6-triphenyl-4H-pyran, 4-(4-methylphenyl)-2,4,6-triphenyl-4H-pyran, and 4-(bromophenyl)-2,4,6-triphenyl-4H-thiopyran also showed photochemical colour changes and finally gave both the phenyl-migrated and the (substituted phenyl)-migrated products in comparable yields in each case. 4-Methyl-2,4,6-triphenyl-4H-thiopyran showed no photochemical colour change in the solid state, but in solution it afforded 4-methyl-2,3,6-triphenyl-2H-thiopyran, whose structure was confirmed by X-ray analysis.Based on comparison with the photochemical behaviour of 2,4,4,6-tetraphenyl-1,4-dihydropyridine and 2,2,4,6-tetraphenyl-1,2-dihydro-1,3,5-triazine, a six-membered ylide was proposed as the coloured photochemical intermediate.
