ABSTRACT
A study that was designed to identify plausible replacements for highly basic guanidine moiety contained in potent MC4R agonists, as exemplified by 1, led to the discovery of initial nonguanidine lead 5. Propyl analog 23 was subsequently found to be equipotent to 5, whereas analogs bearing smaller and branched alkyl groups at the 3 position of the oxopiperazine template demonstrated reduced binding affinity and agonist potency for MC4R. Acylation of the NH2 group of the 4F-D-Phe residue of 3-propyl analog 23 significantly increased the binding affinity and the functional activity for MC4R. Analogs with neutral and weakly basic capping groups of the D-Phe residue exhibited excellent MC4R selectivity against MC1R whereas those with an amino acid had moderate MC4R/MC1R selectivity. We have also demonstrated that compound 35 showed promising oral bioavailability and a moderate oral half life and induced significant weight loss in a 28-day rat obesity model.
Subject(s)
Anti-Obesity Agents/pharmacology , Anti-Obesity Agents/therapeutic use , Obesity/drug therapy , Piperazines/pharmacology , Piperazines/therapeutic use , Receptor, Melanocortin, Type 4/agonists , Administration, Oral , Animals , Anti-Obesity Agents/chemistry , Biological Availability , Diet , Disease Models, Animal , Dogs , Drug Design , Drug Evaluation, Preclinical , Eating/drug effects , Male , Molecular Conformation , Piperazines/chemistry , Rats , StereoisomerismABSTRACT
The design, synthesis, and structure-activity relationships (SAR) of a series of novel proline and pyrrolidine based melanocortin receptor (MCR) agonists are described. To validate a conformationally constrained Arg-Nal dipeptide analogue strategy, we first synthesized and evaluated a test set of cis-(2R,4R)-proline analogues (21a-g). All of these compounds showed significant binding and agonist potency at the hMC1R, hMC3R, and hMC4R. Potent cis-(2S,4R)-pyrrolidine based MCR agonists (35a-g) were subsequently developed by means of this design approach. A SAR study directed toward probing the effect of the two chiral centers in the pyrrolidine ring on biological activity revealed the importance of the (S) absolute configuration at the 2-position for binding affinity, agonist potency, and receptor selectivity. Among the four sets of the pyrrolidine diastereomers investigated, analogues with the (2S,4R) configuration were the most potent agonists across the three receptors, followed by those possessing the (2S,4S) configuration.
Subject(s)
Dipeptides/chemistry , Proline/analogs & derivatives , Proline/chemical synthesis , Pyrrolidines/chemical synthesis , Receptors, Melanocortin/agonists , Binding, Competitive , Cell Line , Humans , Ligands , Molecular Conformation , Molecular Mimicry , Proline/pharmacology , Pyrrolidines/pharmacology , Stereoisomerism , Structure-Activity RelationshipABSTRACT
The design and synthesis of a series of potent 1,3,4-trisubstituted-2-oxopiperazine based MC4 agonists are described. The tripeptidomimetic analogs (12a,b and 23) and the dipeptidomimetic 27 displayed single-nanomolar binding affinity and agonist potency for MC4R and excellent selectivity for MC4R relative to MC1R.
Subject(s)
Drug Design , Guanidines/chemistry , Guanidines/pharmacology , Piperazines/chemistry , Piperazines/pharmacology , Receptor, Melanocortin, Type 4/agonists , Guanidines/chemical synthesis , Molecular Structure , Piperazines/chemical synthesis , Receptor, Melanocortin, Type 4/metabolism , Structure-Activity RelationshipABSTRACT
High-throughput screening of the P&GP corporate repository against several protein tyrosine phosphatases identified the sulfamic acid moiety as potential phosphotyrosine mimetic. Incorporation of the sulfamic acid onto a 1,2,3,4-tetrahydroisoquinoline scaffold provided a promising starting point for PTP1B inhibitor design.
Subject(s)
Enzyme Inhibitors/pharmacology , Protein Tyrosine Phosphatases/antagonists & inhibitors , Sulfonic Acids/pharmacology , Tetrahydroisoquinolines/chemistry , Binding Sites , Binding, Competitive , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Ligands , Models, Molecular , Molecular Mimicry , Phosphotyrosine/metabolism , Protein Binding , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Protein Tyrosine Phosphatases/chemistry , Protein Tyrosine Phosphatases/metabolism , Structure-Activity Relationship , Sulfonic Acids/chemical synthesis , Sulfonic Acids/chemistry , src Homology DomainsABSTRACT
The first synthesis of Tic-D-Phe Psi[CH(2)-CH(2)] isostere is described, which features diastereoselective alkylation of the tricyclic lactam 14. The use of this novel dipeptide isostere in the development of melanocortin agonists has been demonstrated by the synthesis of peptidomimetic 7 and non-peptidic ligand 27. Both compounds displayed significant binding and agonist potency at the MC4R.
Subject(s)
Dipeptides/chemical synthesis , Dipeptides/metabolism , Phenylalanine/chemistry , Receptor, Melanocortin, Type 4/agonists , Alkylation , Dipeptides/chemistry , Humans , Lactams/chemistry , Ligands , Models, Molecular , Molecular Mimicry , Molecular Structure , Receptor, Melanocortin, Type 3/agonists , Stereoisomerism , Structure-Activity RelationshipABSTRACT
As higher density formats become more and more common in HTS labs, the expectations for maintaining faster, lower cost screens puts great pressure on traditional 96-well screens. In some cases higher density formats are not compatible with the assay. This seems especially true in cell-based assays. In our case, the nature of the cells' response forced us to remain in 96-well plates. In this paper, we describe the development of a luminescence reporter assay and its performance in two detection modes, flash and glow. The advantages in cost and throughput for each technique are explored, along with automation considerations. An additional new technology, the use of pins for low-volume transfers, is also briefly described because of its dramatic effect on our screen's throughput. However, it will be more thoroughly presented in a future publication. Comparing the technologies available for HTS aids in designing automated systems that meet the unique needs of each assay.