A new general strategy for the construction of artificial proteins with predetermined tertiary structure is presented. Amphiphilic a -helix and 8-sheet-forming oligopeptides are assembled on a multifunctional template molecule which directs the peptide blocks to adopt characteristic folding topologies. The design, synthesis, and conformational properties of these template-assembled synthetic proteins (TASP) are exemplified for pep-, ahelix-bundle-and /I-barrel-like tertiary structures using specially designed oligopeptides as template molecules. In contrast to linear polypeptide chains of comparable molecular weights, these conceptually novel macromolecules are readily accessible to chemical synthesis and exhibit excellent solubility in a number of solvents. Experimental evidence is provided for a template-induced intramolecular folding to secondary and tertiary structures in aqueous solutions. This approach opens new prospects for the chemical construction of biomacromolecules with tailormade structural and functional properties.

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8-Amino-7-aryl-6-halogen-substituted pyrido[2,3-b]pyrazines have been prepared as 6,6-biheterocyclic analogues of similarly substituted triazolopyrimidine fungicides. A concise four-step synthesis route has been worked out to prepare these novel compounds from commercially available starting materials. [(R)-(1,2-Dimethylpropyl)]-[6-fluoro-7-(2,4,6-trifluorophenyl)pyrido[2,3-b]pyrazin-8-yl]amine showed excellent activity against three economically important phytopathogens.

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A new route to completely protected a-methylated ci -amino acids starting from alanine is described (see Scheme). These derivatives, which are obtained via base-catalyzed opening of the oxazolidinones (2S,4R)-and (2R,4S)-2, can be directly employed in peptide synthesis. The synthesis of both enantiomers of Z-protected a methylaspartic acid p-(tert-buty1)ester (04-(1ert-butyl) hydrogen 2methylaspartates ( R ) or (S)-4a), a-methylglutamic acid y-(tert-butyl) ester (05-(tert-butyl) hydrogen 2-methylglutamate ( R ) -or (S)-4b), and of NL-bis-Bocprotected ci -methyllysine (N6,N6-bis[(fer~-butyloxy)carbonyl]-2-methy~~ysine (R)-or (S)-4c) is described in full detail.