Anny-Odile Colson

Regio- and stereo-controlled copper organometallic addition to a piperidinyl aziridine: synthesis of trans 3-amino-4-alkyl-piperidines

Abstract 3,4-Piperidinyl aziridine N -phosphonate underwent ring opening in Grignard addition catalyzed by a copper reagent to yield trans 3-amino-4-alkyl-piperidines. The nucleophilic addition occurred trans to the aziridine group and regioselectively at C-4 position of the piperidine ring. The high regioselectivity was rationalized by steric argument based on conformational analysis.

Discovery of orally bioavailable 1,3,4-trisubstituted 2-oxopiperazine-based melanocortin-4 receptor agonists as potential antiobesity agents.

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.

Ketopiperazines: Conformationally Constrained Peptidomimetic of Arginine Amides

Abstract We have synthesized guanidine‐containing ketopiperazines designed to be conformational mimics of peptidomimetic arginine amides. D‐Allylglycine was converted by an efficient approach to give enantiopure ketopiperazines in which the trans stereochemistry of the C‐substituents resulted from stereospecific enolate alkylation.