New 1,4-anthracenedione derivatives with fused heterocyclic rings: synthesis and biological evaluation Ma. ´ Angeles Castro, * a Ana Ma. Gamito, a Ver ´ onica Tangarife-Casta ˜ no, b Vicky Roa- Linares, b Jos ´ e Ma. Miguel del Corral, a Ana C. Mesa-Arango, * b Liliana Betancur- Galvis, b Andr ´ es M. Francesch c and Arturo San Feliciano a Several terpenylquinones derived from 1,4-anthracenedione (1,4-anthracenequinone, AQ) have been prepared by addition or substitution nucleophilic reactions and further transformed into extended polycyclic systems, which mainly kept the 1,4-quinone moiety fused to dierent nitrogen-heterocyclic rings (pyrrole, imidazole, pyrazine or quinoxaline) into the structure. The compounds synthesized were evaluated for their antineoplastic, antifungal and antiviral activities. GI 50 antineoplastic values remained under mM levels for AQs, while the heterocyclic derivatives showed antifungal MIC values in the low mg mL 1 range against yeasts and lamentous fungi. Only few compounds displayed a discrete non- selective antiherpetic activity in the mg mL 1 range. 1. Introduction The quinone/hydroquinone moiety is a common structural feature in a large number of natural and synthetic compounds with a wide range of biological activities such as anticancer, 14 antiparasitic, 5 antimicrobial, 6 antifungal, 7 antiviral, 8 anti-oxi- dant, 1b,9 etc., and it is possible to nd agents, derived from benzoquinone (BQ), naphthoquinone (NQ) or anthracenequi- none (AQ), used clinically as anticancer agents 10 such as daunorubicin or mitomycin C (Fig. 1A). The mechanisms of the antineoplastic cytotoxicity of quinone derivatives have been widely studied, and it is known that they usually participate in important biological redox processes and can also act as inter- calating or alkylating agents. 11 The potential of quinones to generate reactive oxygen species (ROS) has been described in the literature, 12 as well as the dierent targets that might be involved in its molecular mechanisms of action depending on the tumour cell type. 13 For instance, the DNA cross-linking and monoalkylation by mitomycin C require the reduction of the quinone ring, while furonaphthoquinones are able to modify the mitochondrial permeability through ROS generation. 12c In this sense, quinones can be considered as multi-target drugs. 14 Several of those bioactive quinones bore a heterocyclic fragment fused to the quinone moiety, including ve and six-membered heterocycles with nitrogen, 15 oxygen 16 and/or sulphur 17 atoms. Fig. 1 (A) Structure of clinically used anticancer quinones. (B) Struc- ture of several monoterpene-derived (MTQ) and diterpene-derived (DTQ) antineoplastic quinones. a Departamento de Qu´ ımica Farmac´ eutica, Facultad de Farmacia, CIETUS-IBSAL, Campus Miguel de Unamuno, Universidad de Salamanca, E-37007 Salamanca, Spain. E-mail: macg@usal.es; Fax: +34 923 294515; Tel: +34 923 294528 b Grupo de Investigaci´ on Dermatol´ ogica, Facultad de Medicina, Departamento de Medicina Interna, Universidad de Antioquia, Medell´ ın, Colombia. E-mail: ana. mesa@udea.edu.co; Tel: +57 4 2196064 c PharmaMar S.A., Avda. de los Reyes, P.I. La Mina Norte, E-28770 Colmenar Viejo, Madrid, Spain Electronic supplementary information (ESI) available: 13 C NMR data and complete assignments for the 1 H and 13 C NMR signals are included together with HMQC and HMBC spectra for several separated regioisomers. Complementary antifungal, antiviral and Vero cytotoxicity data for all the compounds tested. See DOI: 10.1039/c4ra11726c Cite this: RSC Adv. , 2015, 5, 1244 Received 3rd October 2014 Accepted 21st November 2014 DOI: 10.1039/c4ra11726c www.rsc.org/advances 1244 | RSC Adv., 2015, 5, 12441261 This journal is © The Royal Society of Chemistry 2015 RSC Advances PAPER