ber enantiomerenreines (R)-2-Methyl-3-oxo-perhydro-1,4-oxazin

Alkaloids from the root of Isatis indigotica

Seventeen new alkaloids (1-17) and 14 known analogues have been isolated from an aqueous extract of the root of Isatis indigotica. The structures and absolute configurations of these compounds were determined by extensive spectroscopic data analysis, including 2D NMR, single-crystal X-ray crystallography using anomalous scattering of Cu Kα radiation, and electronic circular dichroism spectra calculations based on the quantum-mechanical time-dependent density functional theory. Compounds 1, 2, and 3 are the first examples of natural products with unique linkages between a molecule of 2-(4-methoxy-1H-indol-3-yl)acetonitrile and 2-(1H-indol-3-yl)acetonitrile, 2-(4-methoxy-1H-indol-3-yl)acetonitrile, and 4-hydroxyphenylethane, respectively. Compounds (-)-4 and (+)-4 represent the first natural products with the pyrrolo[2,3-b]indolo[5,5a,6-b,a]quinazoline skeleton. Some structural assignments for the new alkaloids suggest that the assignments made for certain previously reported alkaloids require revision. Compounds 1-3 and arvelexin (18) show antiviral activity against the influenza virus A/Hanfang/359/95 (H3N2), with IC(50) values of 3.70-12.35 μM, and 17 inhibits Coxsackie virus B3 replication with an IC(50) of 6.87 μM.

Syntheses of polymeric vesicles containing partial structures of N-acetyl-muramyl-dipeptide (MDP)

The syntheses of 11-methacroylaminoundecanoyl-L-alanyl-D-isoglutamine (3) and 2-[2-(11-methacroylaminoundecanoyl)aminoethoxy]propanoyl-L- alanyl-D-isoglutamine (13) are described. Each of these monomers has been copolymerized with 11-methacroyloxyundecyltrimethylammonium bromide (16), yielding polymeric vesicles that contain partial structures of N-acetyl muramyl dipeptide (MDP). All products have been characterized by 1H- and 13C-NMR spectroscopy and the polymeric vesicles have been studied by electron microscopy. The potential use of these structures as immunostimulating products is discussed.