10.1021/ja0483037
The research aims to develop a nuclear magnetic resonance (NMR)-based biosensor utilizing laser-polarized xenon, which offers potential advantages over current sensing technologies, such as the ability to detect multiple analytes simultaneously, applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. The study focuses on the binding of a biotin-derivatized caged-xenon sensor to avidin, where specific binding leads to changes in the chemical shift and resonance broadening of the encapsulated xenon, serving as NMR markers of ligand-target interaction. The chemicals used in this process include biotin, avidin, cryptophane-A cages, and xenon gas. The conclusions drawn from the research highlight the potential for tuning the encapsulated xenon chemical shift, which is key for multiplexing the biosensor, and demonstrate methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. The study also discusses the implications of these findings for the application of functionalized xenon biosensors in both ordinary and multiplexing capacities.
10.1002/chem.200400733
The research focuses on the practical synthesis of (+)-biotin from l-cysteine, a significant endeavor due to biotin's crucial role in human nutrition and animal health. The study aims to address the inefficiencies of the existing Goldberg and Sternbach method, which involves over 14 steps, utilizes toxic reagents, and requires impractical diastereomeric or enzymatic resolution. The researchers developed a novel synthetic approach that eliminates the need for bulky protecting groups and reduces the protection-deprotection sequence steps. This method involves the formation of contiguous stereogenic centers through a highly diastereoselective Strecker reaction, a novel ring transformation and deblocking by S,N-carbonyl migration, and the introduction of the carbon chain at C-4 by the Fukuyama coupling reaction. Key chemicals used in the process include l-cysteine, phenyl chloroformate, benzyl bromide, benzyl chloride, sodium bisulfite, sodium cyanide, and various catalysts and reagents for the reactions involved. The conclusions of the research highlight the successful development of a more efficient synthetic method for (+)-biotin, achieved in 10 steps and with an overall yield of 34% from l-cysteine, offering a high yield, ease of operation, and mild reaction conditions.
