H. Kägi

Bio: H. Kägi is an academic researcher from Ciba Specialty Chemicals. The author has an hindex of 8, co-authored 8 publications receiving 197 citations.

Über aktivierte Ester. II. Synthese aktivierter Ester von Aminosäure‐Derivaten

Abstract: The syntheses of a number of cristalline cyanomethyl esters and of some other activated esters of aminoacid and peptide derivatives are described.

Über eine neue Synthese morphinähnlich wirkender 4-Phenylpiperidin-4-alkylketone und verwandter Verbindungen

Abstract: Ausgehend von Benzylcyaniden wird eine neue Synthese von 4-substituierten 4-Phenyl-piperidinen beschrieben, die im wesentlichen auf dem stufenweisen Aufbau des Piperidinringes und der grossen Reaktionsfahigkeit der als Zwischenprodukte erhaltenen 4-Phenyl-4-cyan-piperidiniumsalze beruht. Letztere folgt aus den ungewohnlich milden Bedingungen, unter denen sich folgende Reaktionen durchfuhren liessen: (a) Verseifung der Cyangruppe zum Betain. (b) Vergrignardung der Cyan- zur Alkylketogruppe. (c) Reduktion der Cyan- zur primaren Aminogruppe. (d) Offnung des Piperidinringes.

Synthesis and chemical properties of poly-alpha-amino acids.

Abstract: Publisher Summary The chapter discusses the synthesis and chemical properties of poly-α-amino acids Poly-α-amino acids are synthetic polymers composed of α-amino acid residues linked by peptide bonds They are prepared by polymerization of the corresponding monomers and consist, like other synthetic polymers, of mixtures of homologous macromolecules of varying chain length The preparative methods developed permit the synthesis of a large variety of α-amino acid polymers, in a wide range of average molecular weights A number of different derivatives of α-amino acids and peptides have been used as monomers for the preparation of poly-α-amino acids; the most suitable and commonly used are the N-carboxy-α-amino acid anhydrides (NCAs) These readily undergo polymerization, with carbon dioxide evolution, to yield the corresponding poly-α-amino acids The synthesis of amino acid polymers from the monomers may be accompanied by varying amounts of byproducts that should be removed, during the isolation and purification of the polymer The purification techniques applied are described in the chapter In addition, the methods used to establish the chemical constitution of the polymers and their average molecular weights are given

Isosterism and bioisosterism in drug design.

Abstract: In every scientific undertaking that is to break new ground, one has to have a goal, a working hypothesis, or a leading idea or fact. This will encourage research and help in the pursuit of a worth-while objective, be it the enrichment of knowledge or the elaboration of a practical purpose. A medicinal scientist who hopes to find a new biologically active drug will have to be guided by such considerations.

Reagents for (ir)reversible enzymatic acylations

Abstract: Commonly, hydrolase-catalysed reactions are used for kinetic resolutions of alcohols, amines and acids. Only a few applications in total syntheses have been described. Most of these examples are for the synthesis of amides and peptides. Here, the synthesis of all the different types of activated acids that can be applied in hydrolase-catalysed acylations is described. The application of these activated acids for both the formation of esters and amides is discussed and the different reactions are compared with the equivalent chemical reactions.