The fluorescence behaviour of human orosomucoid was investigated. The intrinsic fluorescence was more accessible to acrylamide than to the slightly larger succinimide, indicating limited accessibility to part of the tryptophan population. Although I- showed almost no quenching, that of Cs+ was enhanced, and suggested a region of negative charge proximal to an emitting tryptophan residue. Removal of more than 90% of sialic acid from the glycan chains led to no change in the Cs+, I-, succinimide or acrylamide quenching, indicating that the negatively charged region originates with the protein core. Quenching as a function of pH and temperature supported this view. The binding of chlorpromazine monitored by fluorescence quenching, in the presence and in the absence of the small quenching probes (above), led to a model of its binding domain on orosomucoid that includes two tryptophan residues relatively shielded from the bulk solvent, with the third tryptophan residue being on the periphery of the domain, or affected allotopically and near the negatively charged field.

Antimalarial activity X 0140Arylmethyl Substituted Derivatives of Fosmidomycin: Synthesis and Antimalarial Activity. -Introduction of an arylmethyl substituent at the α-position of the phosphinic acid moiety of Fosmidomycin and masking the phosphonic acid functionality yield stable, non-hygroscopic Fosmidomycin analogues. Derivative (I) is approximately twice as active as the bis(pivaloyloxymethyl) ester of Fosmidomycin, but less active than the FR900098 prodrug. Since all substituted analogues are tested as racemates, resolution of these compounds should furnish derivatives having improved antimalarial activity. -(SCHLUETER, K.; WALTER, R. D.; BERGMANN, B.; KURZ*, T.; Eur.

Durch Abschirmung der Boratome durch sterisch anspruchsvolle Gruppen gelingt es, bei der Umsetzung von (I) mit zwei bzw. drei Äquivalenten tBuLi die Produkte (II) bzw. (IV) zu erhalten, die mit Neopentyllithium die Tetraalkyldiborane (III) bzw. (V) liefern.

Oxazine derivatives R 0595One-Pot Synthesis of 4-Methoxy(aralkoxy)imino-areno[1,3]oxazin-2-ones. -A procedure for the synthesis of 12 title compounds of type (IV) is presented. The X-ray structure of (IVc) is given. -(KURZ*, T.; WIDYAN, K.; WACKENDORFF, C.; SCHLUETER, K.; Synthesis

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