https://www.selleckchem.com/products/LBH-589.html Somatostatin (SST) analogues have aroused the interest of scientists for years. This group of compounds is used in the diagnosis and treatment of neuroendocrine tumors. However, new molecules useful as radiopharmaceuticals in targeted therapy are still searched for. Bicyclic peptides seem to be very interesting in this context. These molecules are associated with beneficial properties. In this work, we present studies on the binding ability of the bicyclic analogue of somatostatin toward copper(II) ions which could potentially be a chelator for copper radionuclides. The research is focused on the analysis of Cu(II) interactions with the metal binding cycle of the ligand and the influence of the receptor binding site on the coordination process. This is a novelty in comparison to the SST analogues used in medicine, where a metal ion is coordinated by a chelator and connected with a bioactive molecule by the linker. In this work we present the first coordination study for bicyclic ligand. Obtained results showed that the complexes with only imidazole donors are characterized by significantly higher stability in comparison to the other peptides.Phenotypic whole-cell screening against Mycobacterium tuberculosis (Mtb) in GASTE-Fe media led to the identification of a 2-aminoquinazolinone hit compound, sulfone 1 which was optimized for solubility by replacing the sulfone moiety with a sulfoxide 2. The synthesis and structure activity relationship studies (SAR) identified several compounds with potent antimycobacterial activity, which were metabolically stable and non-cytotoxic. Compound 2 displayed favourable in vitro properties and was therefore selected for in vivo pharmacokinetic (PK) studies where it was found to be extensively metabolised to the sulfone 1. Both derivatives exhibited promising PK parameters, however, when 2 was evaluated for in vivo efficacy in an acute TB infection mouse model, it was found to be inact