No abstract

A dynamic imine library formed in solution provides a fast route to drug discovery. Imine formation from diamine 4 and a sublibrary of aldehydes can be used for the efficient discovery of glycosidase inhibitors through a new combinatorial approach. When the equilibrium shown is reached rapidly under dilute conditions, a mixture of imines is produced and can be screened by the glycosidase, which binds preferentially to the best inhibitor.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In recent years, Saturation Transfer Difference NMR (STD NMR) has been proven to be a powerful and versatile ligand-based NMR technique to elucidate crucial aspects in the investigation of protein-ligand complexes. Novel STD NMR approaches relying on “multi-frequency” irradiation have enabled us to even elucidate specific ligand-amino acid interactions and explore the binding of fragments in previously unknown binding subsites. Exploring multi-subsite protein binding pockets is especially important in Fragment Based Drug Discovery (FBDD) to design leads of increased specificity and efficacy. We hereby propose a novel multi-frequency STD NMR approach based on direct irradiation of one of the ligands in a multi-ligand binding process, to probe the vicinity and explore the relative orientation of fragments in adjacent binding sub-sites, which we called Inter-Ligand STD NMR (IL-STD NMR). We proved its applicability on (i) a standard protein-ligand system commonly used for ligand-observed NMR benchmarking: Naproxen as bound to Bovine Serum Albumin, and (ii) the biologically relevant system of Cholera Toxin Subunit B and two inhibitors adjacently bound within the GM1 binding site. Relative to Inter-Ligand NOE (ILOE), the current state-of-the-art methodology to probe relative orientations of adjacent ligands, IL-STD NMR requires about one tenth of the experimental time and protein consumption, making it a competitive methodology with the potential to be applied in the pharmaceutical industries.

Through the reductive amination of N-[(tert-butoxy)carbonyl]-2,5-dideoxy-2,5-imino-3,4-O-isopropylidene-L-ribose with tetramethylenediamine, hexamethylenediamine, 2,7-diaminofluorene, 4,4'-diaminodiphenylmethane and 1,4-(diaminomethyl)benzene, five tetramines containing two (2R,3R,4S)-2-aminomethylpyrrolidine-3,4-diol moieties have been prepared and assayed for their inhibitory activities toward 24 glycosidases. Tetramines containing the tetramethylene or benzene-1,4-dimethylene linkers are more potent α-mannosidase inhibitors than simple (2R,3R,4S)-2-aminomethylpyrrolidine-3,4-diols. Triamines such as (2S,3R,4S)-bis(3,4-dihydroxy-pyrrolidin-2-ethyl)amine were also prepared and shown to be better α-mannosidase inhibitors than (2S,3R,4S)-2-(2-aminoethyl)pyrrolidin-3,4-diol.