Selective Synthesis and X-Ray Structural Analysis of a Pyridocarbazole Derivative

Pyridocarbazole possesses many biological activities such as antimicrobial and antitumor properties. It also serves as a selective inhibitor for cyclic GMP phosphodiesterase (cGMP-PDE) enzyme. Since it is very similar to ellipticine and olivacine, its derivatives are endowed with DNA intercalating properties. One of the pyridocarbazoles, MCDDC, has been synthesized and its stereochemistry has been proven by X-ray crystallographic study. The crystal belongs to the monoclinic space group, P2(1)/a, with cell parameters a = 11.771(3) angstrom, b = 14.557(3) angstrom, c = 11.869(1) angstrom and beta = 101.80(2)degrees. According to the X-ray structure, the entire MCDDC molecule adopts a planar conformation except for the dichlorophenyl ring, which is almost orthogonal to the pyridine ring. Molecules are tightly bound by the N-H center dot center dot center dot N type hydrogen bonds and weak C-H center dot center dot center dot pi interactions also help in packing stabilization.