作者:Hans Cerfontain、J.A.J. Geenevasen
DOI:10.1016/s0040-4020(01)92097-6
日期:1981.1
isomerizations of (E)-β-ionone 1, and of mixtures of the isomeric pyran 2 and (Z)-β-ionone 3 in CD3OD as solvent on direct irradiation with λ 254 nm and on triplet photo-sensitization have been studied at temperatures ⩽ - 50°, where the thermal isomerization between 2 and 3 is fully inhibited. The direct irradiation of 1 at -60° leads to 3 and (Z)-retro-γ-ionone 4 as primary products; 3 is subsequently rapidly
在直接用λ254 nm照射和三重态光敏化的条件下,已将(E)-β-紫罗兰酮1以及异构吡喃2和(Z)-β-紫罗兰酮3的混合物作为溶剂在CD 3 OD中进行了异构化。在⩽-50°的温度下进行了研究,其中2和3之间的热异构化被完全抑制。在-60°处直接照射1会生成3和(Z)-复古-γ-紫罗兰酮4作为主要产物。随后将3迅速地光电转换为2。有证据表明4也是2和3的主要光产物。量子产率比φ2 →4:φ3 → 4⋍0.50。从1或2和3的混合物开始,最终获得1-3的相同光平稳平衡比,即1:2:3×17:72:11。相对于1-3,4是光稳定的。