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Michael addition reactions of O-nucleophiles to C(3) exocyclic nitromethylene derivative of diacetone glucose are reported. The reactions with primary alcohols proceed at ambient temperature in the presence of different bases with good yields and give products with excellent diastereoselectivity. The addition of the nucleophile occurs from the β-face of the carbohydrate as shown by single crystal X-ray analysis. The reactions with secondary alcohols give low yields of products while phenolic compounds do not react. Under certain conditions, isomerization of starting material is observed. [ABSTRACT FROM AUTHOR]

Synthetic approaches to new N-protected γ- and δ-furanoid sugar amino acids (SAAs) or tetrahydrofuran amino acids were developed. SAAs have emerged as valuable building blocks for the syntheses of peptide mimetics, so-called carbopeptoids. 3- C-Substituted 1,2- O-isopropylidene-α- D-allofuranose derivatives were used as starting materials. The designed SAAs contain either cis- or trans-oriented C(3)-aminomethyl and C(4)- or C(5)-carboxylic acid functional groups attached to the 1,2- O-isopropylidene furanoid core, thus providing different spatial arrangements. Short-chain homooligomers derived from a γ-SAA and from a δ-SAA were synthesized as the initial step towards exploration of new carbopeptoids. The key intermediates of these SAA syntheses can easily be transformed into the corresponding molecules containing azide and terminal alkyne moieties and as such have potential for future use for the syntheses of 1,2,3-triazole isosters of peptides. [ABSTRACT FROM AUTHOR]

Recently, monosaccharide-triazole conjugates have proved to possess a large variety of useful biological activities. This paper describes synthesis of a new series of 3-deoxy-3- C-triazolylmethyl-allose derivatives. These new compounds are obtained from acetonide-protected 3-deoxy-3-azidomethyl allose and commercial alkynes via Cu(I) catalyzed 1,3-dipolar cycloaddition. The obtained molecular scaffolds differ from those described earlier by the presence of a methylene linker (-CH-) between the C(3) of allose and the triazole moiety. It was demonstrated that acetonide-protected monosaccharide, 3-deoxy-3- C-(4-phenyl-1 H-1,2,3-triazol-1-yl)methyl-1,2:5,6-di- O-isopropylidene-α-d-allofuranose, inhibited α-L-fucosidase for 26% at 0.1 mM concentration, but a deprotected analog, 3-deoxy-3- C-(4-(4- tert-butylphenyl)-1 H-1,2,3-triazol-1-yl)methyl-β-d-allofuranose, showed 15% inhibition of β-glucosidase at 1 mM concentration. [InlineMediaObject not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The title compound, C13H21NO7 {systematic name: (3aR,5S,6R,6aR)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-6-(nitro-meth-yl)tetra-hydro-furo[2,3-d][1,3]dioxole}, consists of a substituted 2,2-di-methyl-tetra-hydro-furo[2,3-d][1,3]dioxolane skeleton. The furan-ose ring A adopts a (o)T 4 conformation. The fused dioxolane ring B and the substituent dioxolane ring C also have twisted conformations. There are no strong hydrogen bonds in the crystal structure: only weak C-H⋯O contacts are present, which link the mol-ecules to form a three-dimensional structure.

In the title compound, C11H20O8S, the furan-ose ring has a pseudorotation phase angle equal to 31.3° and assumes a (3) T 4 conformation, with deviations of 0.297 (4) and -0.152 (4) Å for the corresponding C atoms. The dioxolane ring adopts an envelope conformation. One of the O atoms is at the flap and deviates from the least-squares plane formed by the other four ring atoms by 0.405 (2) Å. The dihedral angle between the planar fragments of the rings is 63.53 (8)°. In the crystal, mol-ecules are associated into sheets perpendiculer to the b axis by means of O-H⋯O hydrogen bonds. A few weak C-H⋯O inter-actions are also observed.