A general and simple strategy for routine peptide synthesis with alpha,alpha-dialkyl glycines taking advantage of the four-component Ugi-Passerini reaction is presented. The isonitrile required for the reaction can be relatively simple and its selection based on cost, as the group it generates is easily removed under acidic conditions: in addition, this removal is not visibly affected by the bulkiness of the alpha-alkyl groups. Being a good leaving group from the N-terminal amino group of the amino acid, 4-methoxybenzyl was the choice for the amine component of the reaction. The method is illustrated with the synthesis of a series of acyl derivatives of several alpha,alpha-dialkyl glycines. The preparation of the latter compounds is also reported.

Electrospinning and wet-spinning have been recognized as two of the most efficient and promising techniques for producing polymeric fibrous constructs for a wide range of applications, including optics, electronics, food industry and biomedical applications. They have gained considerable attention in the past few decades because of their unique features and tunable architectures that can mimic desirable biological features, responding more effectively to local demands. In this review, various fiber architectures and configurations, varying from monolayer and core-shell fibers to tri-axial, porous, multilayer, side-by-side and helical fibers, are discussed, highlighting the influence of processing parameters in the final constructs. Additionally, the envisaged biomedical purposes for the examined fiber architectures, mainly focused on drug delivery and tissue engineering applications, are explored at great length.

Multicomponent reactions Multicomponent reactions O 0359An Improved Approach for the Synthesis of α,α-Dialkyl Glycine Derivatives by the Ugi-Passerini Reaction. -A general and simple route to bulky α,α-dialkyl glycides using the Ugi-Passerini reaction is presented. The method involves simple procedures in clean reactions and leads to high overall yields, usually above 60%. -(COSTA, S. P. G.; MAIA*, H. L. S.; PEREIRA-LIMA, S. M. M. A.; Org. Biomol. Chem. 1 (2003) 9, 1475-1479; Dep. Quim., Univ. Minho, P-4710 Braga, Port.; Eng.) -Bartels 36-062

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