Unexpected one-pot synthesis of highly conjugated pentacyclic diquinoid compounds.

Alessia Coletti, Sara Lentini, Valeria Conte, Barbara Floris, Olga Bortolini, Fabio Sforza, Fabrizia Grepioni, Pierluca Galloni

Index: J. Org. Chem. 77(16) , 6873-9, (2012)

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Abstract

A new class of pentacyclic diquinoid compounds has been synthesized with a facile one-pot reaction of two molecules of 2-hydroxynaphthoquinone and 1-bromoalkanes in the presence of ferrocene. These molecules were isolated as enol tautomers that exhibit intramolecular hydrogen bond and extended electronic conjugation as proved by the intense absorption spectrum with a broad band between 400 and 600 nm. The spectroscopic and electrochemical characterization of this new class of compounds has been performed. One of the synthesized diquinoid derivatives showed a significant cytotoxicity with IC(50) values of 25-50 μM against Cisplatin-Resistant SKOV3 and colon carcinoma SW480 cell lines. The results of our study provide a valuable tool to a one-pot synthesis of highly conjugated polyquinones, analogous to important biological systems, with significant antitumoral activity.