Abstract
Tetrahydro-1H-benzonin-2,7-dione(2a) has been used as a precursor in the synthesis of dibenzo[b,f][1,5] diazacyclododecene and dibenzo[b,g][1,6]diazacyclododecene ring systems 4 and 5. respectively, via periodate oxidation of the appropriate indolo-benzo[b]azonines 3 and 7. The synthesis of hexahydro-benzo[b][1,4]diazecin-2,7-dione (10) has been achieved by the Schmidt reaction of 2a.
The periodate oxidation of 9,9-methylenebis(2,3,4,9-tetrahydro-1H-carbazole) (11) afforded 1,1'-methylenebis(3,4,5,6-tetrahydro-1H-benzo[b]azonin-2,7-dione) (12). Its 6,6'-methylenebis isomer was obtained by treating 2a with formaldehyde. Oxidation of 16 gave the unsymmetrical bi(benzo[b]azonine) 17.
The Mannich reaction of 2a led to a mixture of its 6-methylene derivative 19 and the spirocyclic system 20. The reactions of 2a with aldimines and aromatic aldehydes were also investigated.