94082-90-3Relevant academic research and scientific papers
Transformations photochimiques d'endoperoxydes derives d'hydrocarbures aromatiques polycycliques III. Photo-isomerisation d'endoperoxydes-1,4 tetrahydroaromatiques
Rigaudy, Jean,Baranne-Lafont, Joele,Ranjon, Andre,Caspar, Alain
, p. 187 - 194 (2007/10/02)
In a previous papers, the thermal and photochemical isomerization of anthracenic 9,10-endoperoxides into unstable meso-diepoxides has been reported.We have now investigated the behaviour of tetrahydro-naphthalenic or anthracenic 1,4-endoperoxides in which other radical processes may compete with isomerization into diepoxides.On photolysis in benzene at long wavelengths, 1,4-epidioxy-1,4-dimethyl-1,2,3,4-tetrahydronaphthalene 4N undergoes mainly an isomerization into 1,8a:4,4a-diepoxy-1,4-dimethyl-1,2,3,4,4a,8a-hexahydronaphthalene 8N, along with a minor cleavage into ethylene and o.diacetylbenzene 10N.Similarly, 1,4-epidioxy-1,4-dimethyl-1,2,3,4-tetrahydroanthracene 4A leads to the hexahydroanthracenic diepoxide 8A and to 2,3-diacetylnaphthalene 10A.These rather unstable diepoxides rearrange spontaneously at room temperature into 2,5-epoxy-2,5-dimethyl-2,3,4,5-tetrahydro-benzo or naphthooxepines 11N and 11A.Their primary formation during photolysis was established by trapping with N-methylmaleimide, which adds on 8N in the 5,8 and on 8A in the 9.10 positions giving the corresponding syn adducts 9N and 9A, and by the isolation of diepoxide 8N at low temperature.Thermolysis of endoperoxides 4N and 4A by refluxing in high boiling solvents leads to very similar results.Photo-oxygenation of diepoxide 8N gives the isomeric 5,8-epidioxy-1,8a:4,4a-diepoxy-1,4-dimethyl-1,2,3,4,4a,5,8,8a-octahydronaphthalenes, syn 13 and anti 14 which can be photo-isomerized into 1,8a:4,4a:5,6:7,8-tetraepoxy-1,4-dimethyl-perhydronaphthalenes, respectively syn 15 and anti 16.
