113972-73-9Relevant academic research and scientific papers
Synthesis, Characterization, and Thermolysis of 7-Amino-7-azabenzonorbornadienes
Carpino, Louis A.,Padykula, Robert E.,Barr, Donald E.,Hall, Frances H.,Krause, Josef G.,et al.
, p. 2565 - 2572 (1988)
Synthetic routes are given for the facile preparation of mono- and dibenzo-7-amino-7-azanorbornadienes 4 and 5.For 5 the key intermediate N-benzylisoindole (9) was treated with benzyne, generated via reaction of o-bromofluorobenzene with magnesium in THF to give tertiary amine 10.N-Bromosuccinimide-mediated debenzylation of 10 gave secondary amine 13, which was then aminated by O-(mesitylsulfonyl)hydroxylamine (MSH).Similarly amination of monobenzo amine 25 gave 4, which, however, proved to be unstable and therefore best isolated as the carbonyl (FMOC) derivative 27.Deblocking of 27 by means of diethylamine gave amine 4 as needed.Upon standing overnight in ether, free 4 underwent self-reduction to give dihydro derivative 29, whereas, in the presence of ethyl phenylpropiolate, cinnamate and dihydrocinnamate esters were formed.The simplest explanation for these results is that a reducing species is ejected upon thermolysis of 4.Nonstereospecific reduction occurred in contrast to the stereospecific reduction that occurred in the presence of authentic diimide precursor 23.Compounds 4 and 5 upon thermolysis in the presence of both acetic acid and propiolate ester led to stereospecific cis reduction.These results suggest that under acidic conditions protonated diimide is generated from both 4 and 5 whereas under neutral condotions 4 may yield azamine or a mixture of azamine and diimide.Direct involvement of 4 and 20 in reduction processes was, however, not eliminated.Thermolysis of 5 under neutral conditions is dependent on the solvent used.In DMF, clean conversion to 9,10-dihydroanthracene occurs whereas complex reaction mixtures are observed in benzene, chloroform, or THF.
