35632-97-4Relevant academic research and scientific papers
Solvent- and Wavelength-Dependence of the Photocleavage of the Cyclobutane Ring in N,N'-Dibutyl-c-3,c-4-bis(2-hydroxyphenyl)-r-1,c-2-cyclobutanedicarboxamide
Yonezawa, Noriyuki,Kubo, Masataka,Saigo, Kazuhiko,Hasegawa, Masaki
, p. 1005 - 1007 (1988)
The ratio between the photocleavage directions of the cyclobutane ring in the title compound varies with the solvent polarity and the irradiation wavelength, and the effect of the solvent polarity appears much larger in protic solvents than aprotic ones.
Symmetric and Asymmetric Photocleavage of the Cyclobutane Rings in Head-to-head Coumarin Dimers and Their Lactone-opened Derivatives
Yonezawa, Noriyuki,Yoshida, Tsuyoshi,Hasegawa, Masaki
, p. 1083 - 1086 (2007/10/02)
The photochemical behaviour of fifteen derivatives of head-to-head coumarin demers has been investigated.The photocleavage of the cyclobutane rings in these compounds in solution occurs on irradiation with light of wavelenght 277 +/- 10 nm to give two molecules of coumarin derivatives via symmetric fission and/or 2,2'-dihydroxystilbene and fumaric (and maleic) acid derivatives via asymmetric fission.The direction of these photofissions is primarily affected by the basic structure of the coumarin dimer derivative, the photocleavage proceeding exclusively with retention of the ring structure when the derivative has a stable five- or six-membered ring fused to its cyclobutane ring.A secondary influence is the steric repulsion between the substituents attached to the cyclobutane ring.
