139928-66-8Relevant articles and documents
An Investigation of the Retro Diels-Alder Reaction as a Method for the Generation of Diatomic Sulfur
Gilchrist, Thomas L.,Wood, Jane E.
, p. 9 - 16 (2007/10/02)
The cyclic disulfides 2,3-dithiabicyclooct-5-ene 5, 1,4-dihydro-2,3-benzodithin 6 and hexahydro-5,8-epoxy-2,3-benzodithiin 7 have been prepared by oxidation of the corresponding dithiols.Each of these compounds has been subjected to vapour phase pyrolysis in order to determine whether a retro Diels-Alder reaction occurs, leading to the formation of diatomic sulfur (S2) and a diene.Compounds 5 and 7 both appeared to decompose in this way; in each case the expected diene was detected in the pyrolysate together with sulfur (S8).Attempts to intercept S2 and thus to obtain direct evidence for its formation were not successful.The benzodithiin 6 underwent an analogous loss of sulfur on vapour phase pyrolysis, but only as a minor reaction pathway, and this decomposition pathway was not detectable in solution pyrolyses.Solution pyrolysis of 6 in the presence of N-phenylmaleinimide gave N-phenyl-2,3-naphthalimide 21 in low yield. cis-Cyclopentene-3,5-dithiol 9 has also been prepared but no evidence could be obtained for the formation of disulfide 4 on oxidation.Reaction of the dithiol 9 with aldehydes and ketones in the presence of acids led to the formation of adducts (such as 12 and 13 from acetone) which were rapidly interconverted in acidic media.
