A new efficient and stereospecific conversion of aminodeoxyalditols into aminoalkyl-substituted tetrahydrofurans

Expanding amphiphilic architectures by ring-opening of epoxides and polyepoxides with N-methyl-d-glucamine: Structure, chiral bias and gelation

The facile reaction of a readily available aminopolyol from the chiral pool, N-methyl-d-glucamine, which avoids the side reactions usually associated to anomers of amino sugars, with epoxide and polyepoxide derivatives, enables the preparation of new non-ionic surfactant-like structures combining hydrophilic and hydrophobic moieties. The molecular architectures thus obtained range from linear to tripodal and pyramidal structures. The resulting substances containing multiple chiral centers exist as diastereomeric mixtures, for which various conformations are likewise possible by virtue of inter-chain interactions. The stability and chirality preferences of all possible stereoisomers have been evaluated in detail by DFT methods. Given the amphiphilic structure of both protected and O-protected derivatives obtained by acetylation, self-aggregation could eventually lead to solvent entrapment. Unfortunately, only one compound behaves as efficient hydrogelator and DMSO-gelator at low concentrations. The issue is also discussed in terms of the different molecular arrangements.

Synthesis and glycosidase inhibitory activity of 1-amino-3,6-anhydro-1-deoxy-D-sorbitol derivatives

3,6-Anhydro-1-(aryl or alkylamino)-1-deoxy-D-sorbitol derivatives have been prepared in four steps from isosorbide, a by-product from the starch industry. The inhibitory activities of these new compounds have been evaluated towards 13 glycosidases. A first lead-compound was identified, which inhibited beta-N-acetylglucosaminidase from bovine kidney (82% inhibition at 1mM).

Synthesis of 2-deoxy-2-(4-nitroimidazol-1-yl)-D-alditols

Small molecules possessing defined configuration at centres of chirality provide a valuable chiral pool. Among different strategies applied for modification of chiral compounds, the most common is to begin with a single stereoisomer and use a synthesis that does not affect the chiral centres. The ANRORC type reaction has been applied for conversion of unprotected 2-amino-2-deoxy-D-hexopyranoses into 2-deoxy-2-(4-nitroimidazol-1-yl)-D-hexopyranoses in a reaction of some 2-aminosugars with 1,4-dinitroimidazoles. The reaction occurs with retention of configuration at C-2 of sugar ring. The products of the reaction were obtained as anomeric mixtures and separated into anomers after acetylation followed by column chromatography. 2-Deoxy-2-(4-nitroimidazol-1-yl)-D-hexopyranoses treated with sodium borohydride in methanolic solution gave the corresponding 2-deoxy-2-(4-nitroimidazol-1-yl)-D-hexitols, characterised as per-O-acetylated derivatives.

Efficient syntheses of 1-bromodeoxy-, 1-azidodeoxy- and 1-aminodeoxypentitols from unprotected D-pentono-1,4-lactones

The reduction of unprotected 5-bromo-5-deoxy-D-ribono, D-arabinono and D-xylono-1,4-lactones was achieved with NaBH4 in water-EtOH. The corresponding 1-bromo-1-deoxypentitols were isolated after acetylation in good overall yields (60-90%). 1-Azido-1-deoxypentitols were obtained quantitatively either by nucleophilic substitution by azide ion and deacetylation of the corresponding monobromopentitols or by reduction of the corresponding 5-azido-5-deoxy-D-pentono-1,4-lactones. The reduction of the monoazidopentitols by catalytic hydrogen transfer gave the monoaminopentitol analogues in quantitative yield.