10.1039/b207936d
The research focuses on the extension of the "ring switch" approach to the synthesis of glutamate antagonists, specifically utilizing δ-lactam urethanes. The study successfully employed three different types of δ-lactam urethane aldehydes (17, 26, and 59) in the synthesis process, manipulating diastereoisomeric ratios through the use of a hindered proton source to obtain homochiral products with two chiral centers. Although the δ-lactam urethane system was less versatile compared to pyroglutamate or β-lactam urethanes, the research managed to prepare a variety of glutamate antagonist homologues. The experiments involved the synthesis of compounds that mimic glutamate, the fast excitatory receptor in the brain, and are potentially useful in treating illnesses such as persistent pain, Alzheimer’s disease, epilepsy, and ischaemia. The methodology, referred to as a "ring switching" reaction, allows for the economical preparation of a large variety of homochiral compounds. The analyses used in the study included various spectroscopic techniques and chromatography to confirm the structures and purities of the synthesized compounds.
10.1016/j.tetlet.2010.03.020
The research presents a new and milder procedure for the synthesis of N-protected α-aminoalkylphosphorylic compounds through the amidoalkylation of hydrophosphorylic compounds. The study involves the reaction of alkyl carbamates, aldehydes, and hydrophosphorylic compounds in acetic anhydride/acetyl chloride. The main reactants include dialkyl phosphites, diethylphosphinous acid, alkylphosphonous acids, methyl and ethyl carbamates, and aldehydes. The experiments led to the isolation of N,N-benzylidene- and N,N-alkylidenebiscarbamates as intermediates for the first time and provided evidence for a new reaction mechanism involving an Arbuzov-type reaction step. The analysis involved the use of 31P NMR spectroscopy to observe the formation of intermediate P–OAc derivatives and the monitoring of reaction yields under various conditions. The study also compared the effectiveness of different catalysts, such as trifluoroacetic acid (TFA) and p-toluenesulfonic acid (TSA), on the reaction yields. The results contribute to a better understanding of the amidoalkylation process and offer an improved method for synthesizing N-protected α-aminoalkylphosphorylic compounds, which are potential substrates in combinatorial peptide synthesis.
T
