Synthesis and glycosidase inhibition of conformationally locked DNJ and DMJ derivatives exploiting a 2-oxo-C-allyl iminosugar.

A series of analogs of the iminosugars 1-deoxynojirimycin (DNJ) and 1-deoxymannojirimycin (DMJ), in which an extra five or six-membered ring has been fused to the C1-C2 bond have been prepared. The synthetic strategy exploits a key 2-keto-C-allyl iminosugar, easily accessible from gluconolactam, which upon Grignard addition and RCM furnishes a bicyclic scaffold that can be further hydroxylated at the C[double bond, length as m-dash]C bond. This strategy furnished DNJ mimics with the piperidine ring locked in a 1C4 conformation with all substituents in axial orientation when fused to a six-membered ring. Addition of an extra ring to DNJ and DMJ motif proved to strongly modify the glycosidase inhibition profile of the parent iminosugars leading to modest inhibitors. The 2-keto-C-allyl iminosugar scaffold was further used to access N-acetylglycosamine analogs via oxime formation.

N-Butyl-l-deoxynojirimycin (l-NBDNJ): Synthesis of an Allosteric Enhancer of α-Glucosidase Activity for the Treatment of Pompe Disease.

The highly stereocontrolled de novo synthesis of l-NBDNJ (the unnatural enantiomer of the iminosugar drug Miglustat) and a preliminary evaluation of its chaperoning potential are herein reported. l-NBDNJ is able to enhance lysosomal α-glucosidase levels in Pompe disease fibroblasts, either when administered singularly or when coincubated with the recombinant human α-glucosidase. In addition, differently from its d-enantiomer, l-NBDNJ does not act as a glycosidase inhibitor.

Stereoselective synthesis of 2-acetamido-1,2-dideoxynojirimycin (DNJNAc) and ureido-DNJNAc derivatives as new hexosaminidase inhibitors.

2-Acetamido-1,2-dideoxyiminosugars are selective and potent inhibitors of hexosaminidases and therefore show high therapeutic potential for the treatment of various diseases, including several lysosomal storage disorders. A stereoselective synthesis of 2-acetamido-1,2-dideoxynojirimycin (DNJNAc), the iminosugar analog of N-acetylglucosamine, with a high overall yield is here described. This novel procedure further allowed accessing ureido-DNJNAc conjugates through derivatization of the endocyclic amine on a key pivotal intermediate. Remarkably, some of the ureido-DNJNAc representatives behaved as potent and selective inhibitors of ß-hexosaminidases, including the human enzyme, being the first examples of neutral sp(2)-iminosugar-type inhibitors reported for these enzymes. Moreover, the amphiphilic character of the new ureido-DNJNAc is expected to confer better drug-like properties.

N-Alkyldeoxynojirimycin derivatives with novel terminal tertiary amide substitution for treatment of bovine viral diarrhea virus (BVDV), Dengue, and Tacaribe virus infections.

Novel N-alkyldeoxynojirimycins (NADNJs) with two hydrophobic groups attached to a nitrogen linker on the alkyl chain were designed. A novel NADNJ containing a terminal tertiary carboxamide moiety was discovered that was a potent inhibitor against BVDV. Further optimization resulted in a structurally more stable lead compound 24 with a submicromolar EC50 against BVDV, Dengue, and Tacaribe; and low cytotoxicity.

An iminosugar N-pentafluorobenzyl-1-deoxynojirimycin as a novel potential immunosuppressant for the treatment of Th2-related diseases.

Increased levels of Th2 cytokine interleukin-4 (IL-4) have been reported to be involved in the pathogenesis of the parasite Schistosoma japonicum (S. japonicum) infection or detected in the serum of the causative agent of acquired immunodeficiency syndrome (AIDS) patients. This correlates with a worsened outcome of AIDS. The inhibition of a Th2 type response might aid in the treatment of these Th2-related diseases. Previously, we found that N-pentafluorobenzyl-1-deoxynojirimycin (5F-DNM), a new derivative of 1-deoxynojirimycin (DNM) (an inhibitor of the glycoprotein processing enzymes, glucosidase I and II), had specific inhibition effects on human CD4(+) T cells. In this study, we further found that 5F-DNM not only markedly inhibited in vitro IL-4 production from human PBMCs, CD4(+) T cells and mouse splenocytes but also strongly inhibited the production of IL-4 in splenocytes from a mouse model of S. japonicum infection. The numbers of S. japonicum worms were significantly decreased in vivo upon the treatment of mice with 5F-DNM. We demonstrated the mechanism of 5F-DNM effects on CD4(+) T cells acts via the inhibition of the IL-4/JAK1/STAT6 signaling pathway. Moreover, 5F-DNM was found to induce CD4 internalization (transfer from the cellular surface to the cytoplasm) in CD4(+) T cells and had no significant effects on the overall expression levels of CD4. These findings indicate that 5F-DNM might be used as a potential candidate for the treatment of S. japonicum parasitic infection, AIDS and other Th2-related diseases.

Synthesis of all-cis 2,5-imino-2,5-dideoxy-fucitol and its evaluation as a potent fucosidase and galactosidase inhibitor.

We here describe a simple and efficient synthetic method for a non-hydrolysable precursor of a GDP-fucose analogue: The synthesis of the racemic aminofuranofucitol 3 from sorbic alcohol by nitroso-Diels-Alder reaction. This 'all-cis-pyrrolidine', with all substituents occupying a cis position, has been determined as a potent inhibitor of α-L-fucosidase and a moderate inhibitor of α- and ß-D-galactosidase. The good recognition of this fucose moiety analogue by specific enzymes is thus confirmed. The C-anomeric bond in this particular structure is in the ß-position and makes this compound an interesting candidate for further chemical modifications. Influence of the methyl and hydroxymethyl groups on the inhibition potency is discussed.

Convergent approach toward the synthesis of the stereoisomers of C-6 homologues of 1-deoxynojirimycin and their analogues: evaluation as specific glycosidase inhibitors.

A new and stereoselective strategy is developed to synthesize an appropriate template 9 to obtain C-6 homologues of 1-deoxyazasugars such as 1-deoxy-D-galactohomonojirimycin (5), 1-deoxy-4-hydroxymethyl-D-glucohomonojirimycin (6), and their enantiomers. The template 9 is also used to obtain neutral nonbasic pseudo-glyconolactam (8), C-4 amino, and methyl analogues of 1-deoxy-homonojirimycin as new analogues of 1-deoxyhomoazasugars. Compound 5 is found to be a potent and specific inhibitor to alpha-galactosidase (Ki = 1.7 microM). Similarly compounds 6 (Ki= 28 microM), ent-5 (Ki= 129 microM), and ent-6 (Ki= 12 microM) exhibited specific inhibition of beta-glucosidase.

A novel approach to the 1-deoxynojirimycin system: synthesis from sucrose of 2-acetamido-1, 2-dideoxynojirimycin, as well as some 2-N-modified derivatives.

6-Azido-1,3,4-tri-O-benzyl-6-deoxy-D-fructofuranose can be easily obtained in two steps from the known 6,6'-diazido-6,6'-dideoxysucrose (available in two steps from sucrose) and cyclized by controlled hydrogenation and concomitant intramolecular reductive amination to give 3,4,6-tri-O-benzyl-1,5-dideoxy-1,5-imino-D-mannitol, a partially protected derivative of 1-deoxymannojirimycin. After N-protection, position 2 is regio-specifically available to modification. This novel approach was taken advantage of in a synthesis of 2-acetamido-1,2- dideoxynojirimycin and new analogues thereof. Results of inhibition studies conducted with these new compounds employing N-acetylhexosaminidases of various sources are discussed.

Sugars with nitrogen in the ring isolated from the leaves of Morus bombycis.

It is known that 1-deoxynojirimycin (1) is contained in the leaves and roots of Morus sp. The modified purification procedures of 1 from leaves of Morus bombycis led to the isolation of many polyhydroxylated alkaloids. These include 1, N-methyl-1-deoxynojirimycin (2), 2-O-alpha-D-galactopyranosyl-1-deoxynojirimycin (3), fagomine (4), 1,4-dideoxy-1,4-imino-D-arabinitol (5), 1,4-dideoxy-1,4-imino-(2-O-beta-D-glucopyranosyl)-D-arabinitol (6), and 1 alpha,2 beta,3 alpha,4 beta-tetrahydroxy-nor-tropane (7), designated nortropanoline. The isolation of 2 is the first report of its natural occurrence. Compounds 3 and 6 are the first naturally occurring glycosides of 1 and 5, respectively. Natural alkaloidal glycosidase inhibitors are classified into five structural types: namely polyhydroxylated piperidines, pyrrolidines, pyrrolines, indolizidines, and pyrrolizidines. Nortropanoline is a novel tropane alkaloid and a new type of polyhydroxylated alkaloid.