The present invention relates to antimicrobial polymyxin derivative compounds and their uses, and in particular to peptide polymyxin antibiotics which may be used in the treatment of bacterial infections such as Gram negative bacterial infections, particularly those caused by multidrug-resistant (MDR) Gram negative bacterial infections.
We have shown that the BuLi/LiDMAE reagent promotes the clean and regioselective C2 lithiation of 3- and 4-chloropyridines, while other reagents such as LDA or BuLi/TMEDA lead to classical ortho lithiation products or mixtures of regioisomers. The method was successfully applied to the preparation of various reactive 2,3- and 2,4-disubstituted pyridines.