New imidazole-based tripodal ligands as Cu(B) site mimics of cytochrome C oxidase

Synthesis and biological evaluation of hypoxia-activated prodrugs of SN-38

We designed new hypoxia-activated prodrugs by conjugating (1-methyl-2-nitro-1H-imidazol-5-yl)methanol with 7-ethyl-10-hydroxy camptothecin (SN-38). Initially, we improved the method of multi-gram scale synthesis of (1-methyl-2-nitro-1H-imidazol-5-yl)methanol, which increased the yield to 42% compared to 8% by the original synthesis method. The improved method was used to synthesize evofosfamide (TH-302) and hypoxia-activated prodrugs of SN-38. Two different linkages between (1-methyl-2-nitro-1H-imidazol-5-yl)methanol and SN-38 were evaluated that afforded different hypoxia-selectivity and toxicity. Compound 16 (IOS), containing an ether linkage, was considered to be a promising hypoxia-selective antitumor agent.

Synthesis, biological evaluation and molecular modelling of sulfonohydrazides as selective PI3K p110alpha inhibitors

A series of 2-methyl-5-nitrobenzenesulfonohydrazides were prepared and evaluated as inhibitors of PI3K. An isoquinoline derivative shows good selectivity for the p110alpha isoform over p110beta and p110delta, and also demonstrates good in vitro activity in a cell proliferation assay. Molecular modelling provides a rationalisation for the observed SAR.

Synthesis and biological evaluation of potential bisubstrate inhibitors of protein farnesyltransferase. Design and synthesis of functionalized imidazoles

A novel series of compounds, derived from 2,5-functionalized imidazoles, have been synthesized as potential bisubstrate inhibitors of protein farnesyltransferase (FTase) using structure-based design. These compounds have a 1,4-diacid chain and a tripeptide connected by an imidazole ring. The synthetic strategy relies on the functionalization at the C-2 position of the heterocycle with the diacid side chain and peptide coupling at the C-5 position. Several new compounds were synthesized in good yields. Kinetic experiments on the most active compounds revealed different binding modes depending on the diacid chain length.

Appending a tris-imidazole ligand with a Tyr 244 mimic on the distal face of bromoacetamidoporphyrin

[structure: see text] Bromoacetamidoporphyrin is a convenient synthon for the attachment of distal superstructures at room temperature in good yields. New models are presented that contain a tris-imidazole distal ligand set bound to the porphyrin in either a binary or trinary fashion. More importantly, one distal imidazole is cross-linked to a phenol mimicking Tyr(244), making this model the closest structural analogue yet reported of the metal free cytochrome c oxidase (CcO) active site.

Synthesis of cytochrome c oxidase models bearing a Tyr244 mimic

A close structural analogue of the metal-free cytochrome c oxidase active site has been synthesized. This model has a proximal imidazole tail and three distal imidazole pickets attached to a porphyrin. One distal imidazole is cross-linked to a phenol, mimicking Tyr(244). The strategy behind the successful synthesis of this regioisomerically pure model involved discovering the best sequence to introduce the phenol-substituted imidazole and employing a fluorinated substituent.