10.1016/S0040-4039(97)00535-2
The research aimed to develop a rapid methodology for the synthesis of peptides in solution, focusing on the selective removal of allylcarbamate protecting groups catalyzed by a water-soluble palladium catalyst. The purpose was to overcome the limitations of conventional peptide synthesis methods, which are hindered by the need for purification and characterization at each step of the peptide chain assembly. The researchers concluded that they had successfully developed a method that allowed for the stepwise synthesis of peptides without the need for intermediate purification, using a key sequence of selective cleavage of the terminal allylcarbamate and peptide coupling. Key chemicals used in the process included Pd(OAc)2 and TPPTS as the palladium catalyst system, diethylamine as an allyl acceptor, and reagents such as DCC/HOBt, TBTU, and PPA for peptide coupling. This approach proved efficient for the synthesis of tri and tetrapeptides, which can serve as fragments for the assembly of larger molecules, and is considered suitable for industrial applications due to its scalability and efficiency.
10.1007/BF00948247
The study focuses on the reaction dynamics of α,β-unsaturated aldehydes with acetone cyanohydrin in the presence of diethylamine. It explores how the structure of the reactants influences the reaction's direction, continuing previous investigations. The research demonstrates that aldehydes like crotonaldehyde and 3,3-dimethylacrylaldehyde react with acetone cyanohydrin and diethylamine to form aminonitriles while maintaining their trans configuration. However, acrolein and certain other aldehydes tend to polymerize under the same conditions. The study also observes a shift in the double bond position in the reaction with trans-octatriene-2,4,6-al, leading to the formation of cyanenamine. The products' structures were confirmed through IR, PMR, and mass spectrometry, along with elemental analysis. The study further investigates the reactions at elevated temperatures, leading to the formation of saturated derivatives of cyanamines. The experimental section details the methods used for GLC analysis, PMR and IR spectroscopy, and mass spectrometry, providing a comprehensive approach to understanding the reaction mechanisms and product characterization.
10.1006/jcht.2001.0853
The research focuses on the thermochemical properties of two compounds, N,N-diethyl-N′-furoylthiourea (HFET) and N,N-diisobutyl-N′-furoylthiourea (HFIB), in both crystalline and gaseous phases. The experiments involved measuring the standard molar enthalpies of combustion and sublimation for these compounds at 298.15 K using rotative bomb calorimetry and high-temperature Calvet microcalorimetry, respectively. The reactants used in the synthesis of these compounds included potassium thiocianate, 2-furoyl chloride, and dialkylamines (diethylamine for HFET and diisobutylamine for HFIB). The synthesized compounds were then subjected to combustion and sublimation analyses to derive their standard molar enthalpies of formation. The calorimetric measurements were calibrated using standard substances like benzoic acid pellets and naphthalene, and corrections were made for factors such as nitric acid formation and energy equivalent of the calorimeter. The results provided insights into the energetic properties of these acylchalcogenoureas, which are important due to their applications as chelating ligands in analytical chemistry and metal separation techniques.
F,
C
