Sang-Uk Kang

N-4-t-Butylbenzyl 2-(4-Methylsulfonylaminophenyl) Propanamide TRPV1 Antagonists : Structure Activity Relationships in the A-region

Structure-activity relationships for the A-region in a series of N-4-t-butylbenzyl 2-(4-methylsulfonylaminophenyl) propanamides as TRPV1 antagonists have been investigated. Among them, the 3-fluoro analogue 54 showed high binding affinity and potent antagonism for both rTRPV1 and hTRPV1 in CHO cells. Its stereospecific activity was demonstrated with marked selectivity for the (S)-configuration (54S versus 54R). A docking study of 54S with our hTRPV1 homology model highlighted crucial hydrogen bonds between the ligand and the receptor contributing to its potency.

α-Methylated simplified resiniferatoxin (sRTX) thiourea analogues as potent and stereospecific TRPV1 antagonists.

A series of α-methylated analogues of the potent sRTX thiourea antagonists were investigated as rTRPV1 ligands in order to examine the effect of α-methylation on receptor activity. The SAR analysis indicated that activity was stereospecific with the (R)-configuration of the newly formed chiral center providing high binding affinity and potent antagonism while the configuration of the C-region was not significant.

Application of Phenylphosphate Mimetics to the Design and Synthesis of Olefin Metathesis-Derived Grb2 SH2 Domain-Binding Macrocycles

Introduction The growth factor receptor bound protein 2 (Grb2) is an SH2 domain-containing component of signaling pathways associated with a variety of proliferative diseases. Grb2 SH2 domains preferentially recognize sequences of the form, “pTyr-Xxx-Asn”, with binding occurring in type-I β-bend conformations [1]. Significant research has been devoted to developing Grb2 SH2 domain-binding peptides and peptide mimetics as potential therapeutics. One aspect of these efforts has been directed toward overcoming bioavailability issues raised by the dianionic phenylphosphate moiety of pTyr. Using an open-chain display platform based on the peptide AcpTyr-Ac6c-Asn-[3-(1-naphthyl)propylamide] reported by Novartis Corp [2], we had previously examined a number of monoanionic phosphoryl mimetics that exhibited micromolar to sub-micromolar Grb2 SH2 domain-binding affinities [3]. More recently, we reported macrocyclic variants of the Novartis peptide bearing dianionic phosphoryl replacements that provide low nanomolar to sub-nanomolar binding constants (analogs 1 [4] and 2 [5], X = a and b, Fig. 1). The focus of the current study was to examine phosphoryl mimicking groups bearing monoanionic charge (X = c,d,e and f) or no charge (X = g and h) within a macrocyclic platform (Fig. 1).