Crystal Structure of a Cis and Trans Isomers of An Indenone Heterocycle Podophyllotoxin Derivative

Trans- indenone

Cis- indenone

                                                                                                                     

                    

                                                          

           

Heterocycles fused with an indenone ring system represent important biological and medicinal scaffolds. Podophyllotoxins have been extensively used as a lead agent in the development of new anticancer drugs. A novel multi-step synthesis involving a reaction of 3,4-dihydronaphthalen-1(2H)-one and 3,5-dibromobenzaldehyde as starting materials yielded the trans and cis analogue in a 1.6:1 ratio. Reaction products from multi-step synthesis were crystallized from the solvent, CHCl₃. The cis-isomer crystallizes in a centro-symmetric triclinic space group of P-1, Z = 2, with two independent molecules in the unit cell with dissimilar geometries, while the trans-isomer crystallizes in an acentric space group P2₁2₁2₁, Z = 4. NMR and IR- spectroscopy do not determine the structure of compounds with a 100% certainty. Only X-Ray diffraction could accurately characterize, determine and confirm the structure of these compounds. Results of testing of cytotoxicity against cancer cells of these and similar materials are ongoing.