Design and synthesis of a maximally diverse and druglike screening library using REM resin methodology

A 3042 compound screening library was synthesized using a combination of two solid-phase technologies: REM resin methodology and Lewis acid promoted aminolysis. The exclusivity and structural diversity of the library were enhanced by using a highly divergent synthetic strategy involving 13 different scaffolds (9 of which were custom-made), five different types of resin-bound phenol derivatization chemistry (Mitsunobu, Suzuki, acylation, sulfonylation, and carbamoylation), and three different cleavage strategies (Hofmann elimination, AlCl3-promoted aminolysis, base-promoted esterolysis). This is the first example of a solid-phase Suzuki coupling involving a resin-bound aryl triflate being used for library synthesis. Computational analysis suggested that the compounds are likely to have favorable properties for CNS penetration. Analysis of the library by HPLC and MS suggested at least 90% of the sampled members were present in an average purity of similar to70%. Encouragingly, hits have been identified from high-throughput screening of this library, such as compound 6, which has an affinity of 1.02 muM for the GlyT(2) transporter.