SYNTHESIS, PROPERTIES, AND CRYSTAL-STRUCTURE OF A 1,1'-BIS(ETHOXYCARBONYL)TRICHOTOMINE DERIVATIVE

On an oxidative dimerization in dichloromethane containing diisopropyl amine, methyl dro-3-oxo-3H-indolizino[8,7-b]indole-5-carboxylate gave a trichotomine derivative bearing ethoxy-carbonyl groups on C1 and C1' . In the presence of triethylamine, the initially formed trichotomine derivative changed to a blue compound, which had the skeleton of the t richotomine derivative and a =CH-CH= group. The X-ray crystallographic analysis of the trichotomine derivative showed the torsion around the central C-C double bond, and the dihedral angle of the adjacent two f ive-membered rings was 30.0-degrees. This torsion is due to the steric interactions between the ethoxycarbonyl groups and the amido carbonyl groups, and might explain the difference of the lambda(max) between t he trichotomine derivative (690 nm) and the blue compound (633 nm).