3,4,9,9a-Tetrahydro-1,4-ethano-3,4a-(iminoethano)-4aH-carbazol-2(1H)-one Derivatives and N,3-Disubstituted 3,3a,4,4a,10,10a-Hexahydro-3a-hydroxy-2-oxo-1,9b:4,10-diethanoimidazocarbazole-5(2H)-carboxamides

Article abstract of DOI:10.1021/jo00337a021

The treatment of 2-<<2-(1H-indol-3-yl)ethyl>imino>cyclohexanone (1) with hot concentrated sulfuric acid to give the pentacyclic compound 4 is described.The treatment of 4 with 2 equiv of isocyanate gave N,3-disubstituted 3,3a,4,4a,10,10a-hexahydro-3a-hydroxy-2-oxo-1,9b:4,10-diethanoimidazo<4,5-b>carbazole-5(2H)-carboxamides 11.When bulky isocyanates were used, the reaction stopped at the diurea stage 10.The latter were irreversibly converted to 11 by heating at 140 deg C.