Oligosaccharides together with oligonucleotides and oligopeptides comprise the three major classes of natural biopolymers. Automated systems for oligonucleotide and oligopeptide synthesis have significantly advanced developments in biological science by allowing nonspecialists to rapidly and easily access these biopolymers. Researchers have endeavored for decades to develop a comparable general automated system to synthesize oligosaccharides. Such a system would have a revolutionary impact on the understanding of the roles of glycans in biological systems. The main challenge to achieving automated synthesis is the lack of general synthetic methods for routine synthesis of glycans. Currently, the two main methods to access homogeneous glycans and glycoconjugates are chemical synthesis and enzymatic synthesis. Enzymatic glycosylation can proceed stereo- and regiospecifically without protecting group manipulations. Moreover, the reaction conditions of enzyme-catalyzed glycosylations are extremely mild when compared to chemical glycosylations. Over the past few years methodology toward the automated chemical synthesis of oligosaccharides has been developed. Conversely, while automated enzymatic synthesis is conceptually possible, it is not as well developed. The goal of this survey is to provide a foundation on which continued technological advancements can be made to promote the automated enzymatic synthesis of oligosaccharides.

The structure and absolute configuration of vibralactone (1) from the cultures of the Basidiomycete Boreostereum vibrans were established by spectroscopic methods and computational methods. Vibralactone, an unusual fused beta-lactone-type metabolite, was found to inhibit pancreatic lipase with an IC50 of 0.4 microg/mL. [structure: see text]

Two novel cyclic hexapeptides containing both anthranilic acid and dehydroamino acid units, sclerotides A (1) and B (2), were isolated from the marine-derived halotolerant Aspergillus sclerotiorum PT06-1 in a nutrient-limited hypersaline medium. Both 1 and 2 are photointerconvertible and could be interconverted via a radical reaction initiated by direct photoisomerization. Both compounds showed moderate antifungal activity. Compound 2 also showed weak cytotoxicity and antibacterial activity.

D-Amino acids exist widely in microbes, plants, animals, and food and can be applied in pharmaceutical, food, and cosmetics. Because of their widespread applications in industry, D-amino acids have recently received more and more attention. Enzymes including D-hydantoinase, N-acyl-D-amino acid amidohydrolase, D-amino acid amidase, D-aminopeptidase, D-peptidase, L-amino acid oxidase, D-amino acid aminotransferase, and D-amino acid dehydrogenase can be used for D-amino acids synthesis by kinetic resolution or asymmetric amination. In this review, the distribution, industrial applications, and enzymatic synthesis methods are summarized. And, among all the current enzymatic methods, D-amino acid dehydrogenase method not only produces D-amino acid by a one-step reaction but also takes environment and atom economics into consideration; therefore, it is deserved to be paid more attention.

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Two new polyphenols containing both phenolic bisabolane sesquiterpenoid and diphenyl ether units, expansols A (1) and B (2), and two new phenolic bisabolane sesquiterpenoids, (S)-(+)-11-dehydrosydonic acid (3) and (7S,11S)-(+)-12-acetoxysydonic acid (4), along with two known compounds, (S)-(+)-sydonic acid (5) and diorcinol (6), were isolated from the metabolites of the marine-derived fungus Penicillium expansum 091006 endogenous with the mangrove plant Excoecaria agallocha. On the basis of spectroscopic analysis, chemical transformation, and theoretical calculation, the structures of 1-4 were elucidated as (S)-(+)-2-[3-hydroxy-4-(2- methoxy-6-methylheptan-2-yl)benzyl]-5-(3-hydroxy-5-methylphenoxy)-3-methylphenol, S-(+)-2-[3-hydroxy-4-(2-hydroxy-6-methylheptan-2-yl)benzyl]-5-(3-hydroxy-5-methylphenoxy)-3-methylphenol, (S)-(+)-3-hydroxy-4-(2-hydroxy-6-methylhept-6-en-2-yl)benzoic acid, and 4-[(2S,6S)-7-acetoxy-2-hydroxy-6-methylheptan-2-yl]-3-hydroxybenzoic acid, respectively. Expansol A (1) exhibited moderate cytotoxicity against the HL-60 cell line with an IC(50) value of 15.7 microM, and expansol B (2) inhibited the proliferation of A549 and HL-60 cells with IC(50) values of 1.9 and 5.4 microM, respectively.

The gas-phase non-identity S N 2 reactions on nitrogen Y Ϫ ϩ NMe 2 X 3 NMe 2 Y ϩ X Ϫ (Y, X ϭ F, Cl, Br, and I) were evaluated at the G2(ϩ) level. The reactions are exothermic only when the nucleophile is the lighter halide. The complexation enthalpies for complexes Y Ϫ . . . Me 2 NX are found to correlate with electronegativity of X. Both central and overall barriers can be interpreted with the aid of Marcus equation. Kinetic and thermodynamic investigations predict that the nucleophilicity of X Ϫ decreases in the order: F Ϫ Ͼ Cl Ϫ Ͼ Br Ϫ Ͼ I Ϫ and the leaving-group ability increases in the order: F Ͻ Cl Ͻ Br Ͻ I. (J Am Soc Mass Spectrom 2004, 15, 673-680)

[structure: see text]. Lancifodilactone G (1), a novel, highly oxygenated nortriterpenoid featuring a partial enol structure and a spirocyclic moiety, was isolated from the medicinal plant Schisandra lancifolia. Its structure and stereochemistry were determined from extensive one- and two-dimensional NMR and mass spectral data, coupled with single-crystal X-ray analysis. Compound 1 exerted minimal cytotoxicity against C8166 cells (CC50 > 200 microg/mL) and showed anti-HIV activity with EC50 = 95.47 +/- 14.19 microg/mL and a selectivity index in the range of 1.82-2.46.