Synthesis of isotopomers of N-(tert-butoxycarbonyl)-4-cyano-l-phenylalanine methyl ester: choice of cyanation solvent
作者:Christopher G. Bazewicz、Jacob S. Lipkin、Kristen A. Lozinak、Matthew D. Watson、Scott H. Brewer
DOI:10.1016/j.tetlet.2011.10.050
日期:2011.12
N-(tert-butoxycarbonyl)-4-cyano-L-phenylalanine methyl ester and three isotopomers ((CN)-N-15, (CN)-C-13, and (CN)-C-13-N-15) were successfully synthesized in two steps to expand the utility of the nitrile symmetric stretch vibration of this modified amino acid as a vibrational reporter of local environments. The choice of cyanation solvent directly impacted the level of isotopic enrichment of the isotopomers. The commonly used solvent acetonitrile resulted in an isotopic enrichment of only similar to 80% with a cyanation reaction time of 4.5 h, however, the cyanation solvent N,N-dimethylformamide afforded the isotopomers with >98% isotopic enrichment. (C) 2011 Elsevier Ltd. All rights reserved.