Abstract: Disclosed is a process for the manufacture of pseudo proline dipeptides of the formula wherein R1 is a side chain of an alpha amino acid, R2 is an amino protecting group and R3 and R4 are independently either hydrogen or C1-4-alkyl, and R5 is hydrogen or methyl starting from an amino acid derivative of the formula wherein R1 and R2 are as defined above. Pseudo proline dipeptides can be used as reversible protecting groups for Ser, Thr and Cys and thus are versatile tools in peptide chemistry.

Abstract: Disclosed is a process for the manufacture of pseudo proline dipeptides of the formula wherein R1 is a side chain of an alpha amino acid, R2 is an amino protecting group and R3 and R4 are independently either hydrogen or C1-4-alkyl, and R5 is hydrogen or methyl starting from an amino acid derivative of the formula wherein R1 and R2 are as defined above. Pseudo proline dipeptides can be used as reversible protecting groups for Ser, Thr and Cys and thus are versatile tools in peptide chemistry.

Abstract: The invention relates to a method for improving the quality of soldered connections between large-area SMD components and wiring carriers, in the case of which the parts to be joined are electrically and mechanically connected to one another by reflow soldering, a flux being used to activate the solder. The intention of the invention is to provide a method of improving the quality of soldered connections which is simple to realize and particularly effective and with which the number of voids can be drastically reduced. According to the invention, this is achieved by the parts to be joined being positioned one over the other and connected to each other by forming a force of adhesion and by the parts to be joined being arranged in such a way that they are tilted at a predetermined tilting angle with respect to the normal plane, at least during the melting of the solder paste. The tilting angle during the melting should lie between greater than 0° and less than 180° and preferably be about 90°.

Abstract: The invention relates to a method for improving the quality of soldered connections between large-area SMD components and wiring carriers, in the case of which the parts to be joined are electrically and mechanically connected to one another by reflow soldering, a flux being used to activate the solder. The intention of the invention is to provide a method of improving the quality of soldered connections which is simple to realize and particularly effective and with which the number of voids can be drastically reduced. According to the invention, this is achieved by the parts to be joined being positioned one over the other and connected to each other by forming a force of adhesion and by the parts to be joined being arranged in such a way that they are tilted at a predetermined tilting angle with respect to the normal plane, at least during the melting of the solder paste. The tilting angle during the melting should lie between greater than 0° and less than 180° and preferably be about 90°.