Research Article For reprint orders, please contact: reprints@future-science.com Synthesis and structure–activity relationships of novel abietane diterpenoids with activity against Staphylococcus aureus Macarena Funes Chab ´ an ‡,1 , Antonia I Antoniou ‡,2 , Catherine Karagianni 2 , Dimitra Toumpa 2 , Mariana Bel ´ en Joray 1 , Jos´ e Luis Bocco 3 , Claudia Sola 3 , Constantinos M Athanassopoulos* ,2 & Mar´ıa Cecilia Carpinella** ,1 1 Research Institute of Natural Resources & Sustainability Jos ´ eS´ anchez Labrador S.J. (IRNASUS-CONICET), School of Chemistry, Catholic University of C ´ ordoba, C ´ ordoba, Argentina 2 Synthetic Organic Chemistry Laboratory, Department of Chemistry, University of Patras, Patras, Greece 3 CIBICI-CONICET & Department of Clinical Biochemistry, Faculty of Chemical Science, National University of C ´ ordoba, C ´ ordoba, Argentina * Author for correspondence: Tel.: +30 2610 997909; kath@chemistry.upatras.gr **Author for correspondence: Tel.: +54 351 4938000, ext 611; Fax: +54 351 4938061; ceciliacarpinella@ucc.edu.a ‡ Authors contributed equally Aim: To find alternative compounds against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA), novel derivatives from dehydroabietic acid were synthesized. Methods & results: Compound 12 was the most effective against 15 MRSA and 11 MSSA with minimum inhibitory concentration values ranging from 3.9 to 15.6 μg/ml. Although less active than 12, compound 11, followed by 25 and 13, also exhibited anti-staphylococcal activity. Additional studies showed that com- pound 12 is devoid of toxic effect on non-target cells. A structure–activity relationship study revealed that an oxime at C-13 together with a hydroxyl at C-12 could play a key role in the activity. Conclusion: These structures, in particular compound 12, could arise as templates for the development of agents against MRSA and MSSA. Graphical abstract: Dehydroabietic Acid COOH Compounds Library N H COOMe OH OH N COOMe Antibacterial activity against 15 MRSA and 11 MSSA strains (MICs = 3.9–62.5 μg/ml) OH OH N COOMe OH OH N COOMe OH OH 11 12 13 N OH 25 SAR study N COOMe OH OH First draft submitted: 26 June 2019; Accepted for publication: 8 October 2019; Published online: 16 December 2019 Future Med. Chem. (2019) 11(24), 3109–3124 ISSN 1756-8919 3109 10.4155/fmc-2019-0192 C  2019 Newlands Press