A Short and Scalable Route to OrthogonallyO-Protected 2-Deoxystreptamine

Synthesis of Ring II/III Fragment of Kanamycin: A New Minimum Structural Motif for Aminoglycoside Recognition

A novel protocol has been established to prepare the kanamycin ring II/III fragment, which has been validated as a minimum structural motif for the development of new aminoglycosides on the basis of its bactericidal activity even against resistant strains. Furthermore, its ability to act as a AAC-(6′) and APH-(3′) binder, and as a poor substrate for the ravenous ANT-(4′), makes it an excellent candidate for the design of inhibitors of these aminoglycoside modifying enzymes.

Synthesis of Glycosidic (β-1''→6, 3' and 4') Site Isomers of Neomycin B and their Effect on RNA and DNA Triplex Stability

Glycosidic (β-1''→6, 3' and 4') site isomers of neomycin B (i.e., neobiosamine (β-1''→6, 3' and 4') neamines) have been synthesized in a straightforward manner. Peracetylated neomycin azide was used as a common starting material to obtain neobiosamine glycosyl donor and 6, 3',4'-tri-O-acetyl neamine azide that after simple protecting group manipulation was converted to three different glycosyl acceptors (i.e., 5,6,4'-, 5,3',4'- and 5,6,3'-tri-O-acetyl neamine azide). Glycosylation between the neobiosamine glycosyl donor and the neamine-derived acceptors gave the protected pseudo-tetrasaccharides, which were converted, via global deprotection (deacetylation and reduction of the azide groups), to the desired site isomers of neomycin. The effect of these aminoglycosides on the RNA and DNA triplex stability was studied by UV-melting profile analysis.

Chiral phosphoric acid-catalyzed desymmetrizative glycosylation of 2-deoxystreptamine and its application to aminoglycoside synthesis

This work describes chiral phosphoric acid (CPA)-catalyzed desymmetrizative glycosylation ofmeso-diol derived from 2-deoxystreptamine.

Structure-guided discovery of a novel aminoglycoside conjugate targeting HIV-1 RNA viral genome

The dimerization initiation site (DIS) of the HIV-1 genomic RNA is a conserved stem-loop that promotes viral genome dimerization by forming a loop-loop complex. The DIS constitutes a potentially interesting target because it is crucial for several key steps of the viral replication. In this work we describe the synthesis of a rationally designed aminoglycoside conjugate that binds the HIV-1 DIS viral RNA with high specificity, as shown by an extensive in vitro binding characterization. We propose a three-dimensional model of the drug-RNA interaction that perfectly fits with binding data. Our results show the feasibility of targeting the HIV DIS viral RNA dimer and open the way to the rationale design of a new class of antiviral drugs. In addition, due to similarities between the HIV-1 DIS RNA and the bacterial aminoacyl decoding site (A site) RNA, we show that this novel aminoglycoside conjugate also binds the bacterial A site with a similar affinity as natural aminoglycoside antibiotics.

2-Deoxystreptamine Conjugates by Truncation-Derivatization of Neomycin

A small library of truncated neomycin-conjugates is prepared by consecutive removal of 2,6-diaminoglucose rings, oxidation-reductive amination of ribose, oxidation-conjugation of aminopyridine/aminoquinoline and finally dimerization. The dimeric conjugates were evaluated for antibacterial activity with a unique hemocyanin-based biosensor. Based on the outcome of these results, a second-generation set of monomeric conjugates was prepared and found to display significant antibacterial activity, in particular with respect to kanamycin-resistant E. coli.

Asymmetric desymmetrization of 4,5-epoxycyclohex-1-ene by enantioselective allylic oxidation

Asymmetric desymmetrization of allylic oxidation of 4,5-epoxycyclohex-1-ene (1) took place in the presence of 2.5 mol % of Cu(CH(3)CN)(4)PF(6) and 3 mol % of chiral N,N-bidentate ligand (S)-2 to afford (3S,4S,5S)-3-benzoyloxy-4,5-epoxycyclohex-1-ene (3) in 84% ee, which was increased up to >99% ee after recrystallization of 3-4'-nitrobenzoyloxy derivative 6. Optically pure 6 proved to be a key intermediate for enantioselective synthesis of O-protected 2-deoxystreptamine (2-DOS) precursor 12.

Synthesis of aminoglycoside conjugates of 2'-O-methyl oligoribonucleotides

Aminoglycoside conjugates of 2'- O-methyl oligoribonucleotides have been synthesized entirely on a solid phase using conventional phosphoramidate chemistry. For this purpose, appropriately protected neamine-derived phosphoramidites, viz., 2-cyanoethyl [6,3',4'-tri- O-levulinoyl- N (1), N (3), N (2) (') , N (6) (') -tetra(trifluoroacetyl)neamine-5- O-ethyl] N,N-diisopropylphosphoramidite, 1, and 2-cyanoethyl [6,3',4',2'',3''-penta- O-levulinoyl- N (1), N (3), N (2) (') , N (6) (') -tetra(trifluoroacetyl) ribostamycin-5''-yl] N, N-diisopropylphosphoramidite, 2, have been prepared and attached via phosphodiester linkage to an appropriate 2'- O-methyl oligoribonucleotide. Levulinoyl esters are used to cap the hydroxyl groups of the aminoglycoside moieties, since they may be selectively removed prior to ammonolysis. In this manner, the potential O-->N acyl migration is excluded. Applicability of the strategy has been demonstrated by the synthesis of eight different aminoglycoside conjugates, in which 1 and 2 are attached directly to the 5'-end ( 6 and 10) or, alternatively, to an inserted non-nucleosidic hydroxyalkyl armed branching unit ( 3, 4, or 5), which results in intrachain conjugates ( 7- 9, 11- 13). The potential of these conjugates to act as a sequence-selective artificial nuclease has been studied.