An efficient solid-phase synthesis of mono-N-substituted piperazines is presented. The key transformation involves a selective borane amide bond reduction in the presence of a carbamate resin linkage. This synthetic route takes advantage of the large diverse pool of commercially available carboxylic acids, acid chlorides, and sulfonyl chlorides. The solid-phase approach facilitates parallel processing by eliminating the need for column chromatography after each synthetic step. The N-monosubstituted piperazines were shown to react with polymeric activated tetrafluorophenol (TFP) reagents to generate arrays of amides and sulfonamides in good purity for biological testing.

AbstractÐThe highly selective I 1 -PBS imidazoline analogue PMS 952 has been selected to study the incidence of intramolecular hydrogen bond and molecular ilexibility on its biological activity. On one hand, the weak energy dierence between three calculated conformers does not support the stabilization of one conformer by an internal hydrogen bond. The 3-D electrostatic map con®rms this feature and the solvent eect does not signi®cantly modify the relative energy of these conformers. On the other hand, the conformational spaces of the neutral and ionized forms present a great number of equilibrium structures, in a short energetic range (20 Kcal). The results are representative of an exceptional conformational¯exibility due to a cooperative eect between several parts of the molecule. #

Herein we report the discovery of a novel biaryl amide series as selective inhibitors of hematopoietic protein kinase 1 (HPK1). Structure–activity relationship development, aided by molecular modeling, identified indazole 5b as a core for further exploration because of its outstanding enzymatic and cellular potency coupled with encouraging kinome selectivity. Late-stage manipulation of the right-hand aryl and amine moieties surmounted issues of selectivity over TRKA, MAP4K2, and STK4 as well as generating compounds with balanced in vitro ADME profiles and promising pharmacokinetics.