71650-88-9Relevant academic research and scientific papers
Synthesis, Thermal Stability, and Chemiluminescence Properties of Bisdioxetanes Derived from p-Dioxines
Adam, Waldemar,Platsch, Herbert,Schmidt, Ernst
, p. 4385 - 4403 (2007/10/02)
By elimination of methanol from 2,5-dimethoxy-1,4-dioxanes and 2,3-dihydro-2-methoxy-1,4-dioxines on treatment with p-toluenesulfonic acid in acetic anhydride, the new tetrakis(4-methoxyphenyl)-, tetrakis(4-chlorophenyl)-, tetra-p-tolyl-, and 2,5-dimethyl-3,6-diphenyl-1,4-dioxines (1) were prepared in good yields.Photosensitized singlet oxygenation of these 1,4-dioxines 1 afforded the corresponding bisdioxetanes 2, the 1,2-diketones, and the enediol diesters 7.Thermal decomposition of the bisdioxetanes 2 yielded the corresponding anhydrides 4 essentially quantitatively.During the thermolysis of 1,6-dimethyl-3,8-diphenyl-2,4,5,7,9,10-hexaoxatricyclo3,6>decane (2f) appreciable amounts of (3R,4S)-3-acetoxy-4-(benzoyloxy)-4-methyl-3-phenyl-1,2-dioxetane (3f) were detected.The bisdioxetanes 2 and monodioxetane 3f exhibited similar thermal stabilities, the free energies of activation (ΔG%) at 298 K falling within 25.5 + 1.5 kcal/mol.The singlet excitation yields (ΦS) ranged between 0.003 and 0.03percent and the triplet excitation yields (ΦT) between 9.5 and 71.5percent.Despite the favorable energy balance, it is concluded that no higher excited states of anhydride 4f are produced during the thermolysis of bisdioxetane 2f.On thermal activation, the bisdioxetanes decompose by sequential cleavage of the two dioxetane rings.
