Synthesis and structure of a helical diindenophenanthrene with four congested phenyl substituents as a molecular spiral staircase

Treatment of 9 with potassium tert-butoxide produced 10 having a helical twist in a single operation. The X-ray structure of 10 shows that the four phenyl substituents are essentially parallel to one another but are virtually perpendicular to the helical axis of the diindenophenanthrene ring system. Viewing from the direction perpendicular to the helical axis, the structure of 10 resembles that of a segment of a spiral staircase having four parallel steps.     

Hesseltin A, a novel antiviral metabolite from Penicillium hesseltinei

[structure: see text] Hesseltin A 1, a novel compound of mixed polyketide-terpenoid origins was isolated from the filamentous fungus Penicillium hesseltinei. The structure and stereochemistry were determined from extensive one- and two-dimensional NMR and mass spectral data.     

Synthesis and evaluation of new potential HIV-1 non-nucleoside reverse transcriptase inhibitors. New analogues of MKC-442 containing Michael acceptors in the C-6 position

Analogues of MKC-442 capable of undergoing Michael addition reactions were synthesised in order to investigate the activity against the HIV-1 mutant (Y181C). An improved activity was postulated on the basis of a possible covalent binding to the mercapto group of Cys181. Lithiation of the C-6 position of 1-ethoxymethyl-5-ethyl-1H-pyrimidine-2,4-dione (5) was followed by reaction with alpha,beta-unsaturated aldehydes and oxidation of the alcohols formed to give the alkenoyl analogues 1a-3a. Analogues 1b-3b containing an allyloxymethyl group in the N-1 position instead of the ethoxymethyl group could not be synthesised due to isomerisation of the allylic group during the metallation reaction. The NMR data for compounds 1a-3a showed a hindered rotation, which was more pronounced for the 6-cyclohexenylcarbonyl derivative 3a than for the propenyl derivatives 1a and 2a. Moderate activity against wild type HIV-1 was observed for the alcohol 8 and the ketones 2a-3a. However, no activity was observed against the Y181C mutant.     

Using light to bioactivate surfaces: A new way of creating oriented, active immunobiosensors

Ultraviolet light can be used to immobilize biomolecules onto thiol reactive surfaces in order to, e.g., make biosensors. The mechanism involves light-induced formation of free, reactive thiol groups in disulphide containing molecules. This technology allows for the creation of arrays of biomolecules with a high degree of reproducibility, circumventing the need for often expensive nano/micro-dispensing technologies. The ultimate size of the immobilized spots is defined by the focal area of the UV beam. Light-induced immobilization has the added benefit that the immobilized molecules will be spatially oriented and covalently bound to the surface. In this paper, we demonstrate the utility of a sensor array created with the new sensor technology when integrated into a microfluidic system. Protein arrays made using light-induced immobilization showed successful antigen/antibody binding in a flow cell allowing the visualisation of real time binding and enzyme activity. This new technology is ideal for the creation of protein/DNA microarrays, can replace present micro-dispensing arraying technologies and is ideal as a molecular imprinting technology.     

Hesseltins B-G, novel meroterpenoids from a new Penicillium species

Six new meroterpenoid compounds, hesseltins B-G, were isolated from Penicillium species along with the previously described hesseltin A. A further 14 compounds, which turned out to be photoisomers, were detected during purification and were subsequently isolated. The structures of these analogues were elucidated by comparison of their NMR spectral data with that of hesseltin A. None of the new hesseltins showed antiviral activity in a Herpes simplex virus type 2 assay.     

Die neueren Verfahren der Flotation

Ohne Zusammenfassung     

Synthesis of C-8 Deuterated Glycosides of 3-Deoxy-D-manno-oct-2-ulosonic Acid (Kdo) Related to Chlamydial Lipopolysaccharides

Summary.  Methyl glycosides of Kdo and a (2→8)-linked Kdo disaccharide were prepared which contain a deuterium label at C-8 of the reducing unit. The label was introduced in fair diastereoselectivity upon reduction of an aldehyde group using a chiral borane complex derived from N-benzyloxycarbonyl-(S)-proline which produced the 8-(S)-deuterated derivative as the major isomer. Further coupling with a Kdo bromide gave the α-(2→8)-linked disaccharide in good yield. The deprotected disaccharide serves as a model for NMR spectroscopic studies on the side chain conformation of a carbohydrate epitope from the bacterial pathogen Chlamydia. Received September 17, 2001. Accepted October 17, 2001