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The interaction of alpha- and beta-oligoarginine amides and acids and of alpha-polyarginine with anionic lipid vesicles is investigated. A mechanism is described from the obtained data by which oligoarginines interact with anionic vesicles, such as initial electrostatic interaction that is fast, nonspecific and relatively weak and nonelectrostatic interaction that is rate-limiting, stronger and includes bilayer rigidification as well as release of aqueous contents from the vesicles.

A novel bacterial strain that was capable of growing on the [beta]-tripeptide H-[beta]hVal-[beta]hAla-[beta]hLeu-OH as the sole carbon and nitrogen source was isolated from an enrichment culture. On the basis of physiological characterization, partial 16S rRNA sequencing, and fatty acid analysis, strain 3-2W4 was identified as a member of the family Sphingomonadaceae. Growth on the [beta]-tripeptide and the [beta]-dipeptide H-[beta]hAla-[beta]hLeu-OH was observed, and emerging metabolites were characterized. Small amounts of a persisting metabolite, the N-acetylated [beta]-dipeptide, were identified in both media. According to dissolved organic carbon measurements, 74 to 80% of the available carbon was dissimilated. The [beta]-peptide-degrading enzyme was purified from the crude cell extract of cells from strain 3-2W4 grown on complex medium. The enzyme was composed of two subunits, and the N-terminal sequences of both were determined. With this information, it was possible to identify the complete nucleotide sequence and to deduce the primary structure of the gene bapA. The gene encoded a [beta]-peptidyl aminopeptidase (BapA) of 402 amino acids that was synthesized as preprotein with a signal sequence of 29 amino acids. The enzyme was cleaved into two subunits (residues 30 to 278 and 279 to 402). It belonged to the N-terminal nucleophile (Ntn) hydrolase superfamily.

Research has been conducted on the cis-stilbene. The epoxidation of this compound by the oxygen donors catalyzed by the Mn (super)III (salen)x complexes has been carried out in producing cis- and trans-epoxides and the details are reported.

Research has been conducted on the N,S-acetals derived from oxazolidinone. The lithiation of these acetals has been carried out and their use as chiral nucleophilic formylation reagents has been investigated.

Titanium Lewis acid Ti-TADDOLates are used as chiral in the enantioselective isopropyl hemiester formation from cyclic meso-anhydrides through a ring opening reaction. Highly enantioselective isopropyl hemiesters can be generated from a range of structurally diverse anhydrides. The reaction proceeds either by desymmetrization through enantiotopic carbonyl compound differentiation or racemic compound kinetic resolution.

A phenethyl replacement at the N(3) of 2-alkyl-substituted 1,3-imidazolidinones increases the diastereoselectivity of the alkylation of these compounds. For hetereocycles with 2-isopropyl and 2-tert-butyl substitutents, the diastereoselectivities are in the order of 19:1 and 49:1 respectively. After substitution with phenethyl group, the conformation of the isopropyl substituent is constant, ensuring avoidance of electrophilic addition to the enolate face syn to the isopropyl group.

Diels-Alder addition of 3-butenoyls-1,3-oxazolin-2-one to cyclopentadiene subjected to catalytic amounts of dichloro-Ti complexes of alpha,alpha,alpha',alpha'-tetraaryl-1,3-dioxolane-4,5-dimethanols (TADDOLs) is investigated. The investigation reveals that the Ti-BINOLate- and Ti-TADDOLate mediated reactions of electrophiles having nucleophiles is identical to the reactions associated with the nucleophilic organometallic additions to carbonyl groups.

The conformation of cyclosporin A (CsA) with lithium chloride in THF-d8 is investigated via NMR spectroscopy. Complexation with lithium results in the loss of the beta-stranded sheet within the betaII' turn and the three transannular hydrogen bonds found in free CsA solution. On the contrary, a new betaII'-turn-like structure is observed between residues 7 and 10, which do not possess a hydrogen bond between residues i and i+3.

Methyl crotonate and (S)-1-phenylethylamine can undergo Michael addition with subsequent hydrogenation and hydrolysis to provide the (R)- and (S)-3-aminobutanoic acids. The converted amide and Schiff base products of the aminobutanoic acids have been cyclized and treated with benzoyl chloride/DMAP to produce four stereoisomeric perhydropyrimidinones in adequate yields. The resulting compound can be subjected to further alkylation to form heterocycles which upon hydrolysis yields free amino acids.