Structure-Activity Studies of N-Butyl-1-deoxynojirimycin (NB-DNJ) Analogues: Discovery of Potent and Selective Aminocyclopentitol Inhibitors of GBA1 and GBA2.

Analogs of N-butyl-1-deoxynojirimycin (NB-DNJ) were prepared and assayed for inhibition of ceramide-specific glucosyltransferase (CGT), non-lysosomal -glucosidase 2 (GBA2) and the lysosomal -glucosidase 1 (GBA1). Compounds 6a-6f that carry sterically demanding nitrogen substituents, and compound 14, devoid of the C3 and C5 hydroxyl groups present in DNJ/NB-DGJ (N-butyl-deoxygalactojirimycin showed no inhibitory activity for CGT or GBA2. Inversion of stereochemistry at C4 of N-(n-butyl)- and N-(n-nonyl)-DGJ (compounds 25) also led to a loss of activity in these assays. The aminocyclopentitols N-(n-butyl)- (36a), N-(n-nonyl)-4-amino-5-(hydroxymethyl)cyclopentane- (36b), and N-(1-(pentyloxy)methyl)adamantan-1-yl)-1,2,3-triol (36f), were selective inhibitors of GBA1 and GBA2 that did not inhibit CGT (>1mM) with the exception of 36f, which inhibited CGT with an IC50 of 1 mM. The N-butyl analog 36a was 1000-fold selective for inhibiting GBA1 over GBA2 (Ki values of 32 nM and 3.3 μM for GBA1 and GBA2, respectively). The N-nonyl analog 36b displayed a Ki of <<14 nM for GBA1 inhibition and a Ki of 43 nM for GBA2. The N-(1-(pentyloxy)methyl)adamantan-1-yl) derivative 36f had Ki values of ~16 nM and 14 nM for GBA1 and GBA2, respectively. The related N-bis-substituted aminocyclopentitols were significantly less potent inhibitors than their mono-substituted analogs. The aminocyclopentitol scaffold should hold promise for further inhibitor development.