DFT investigation of coupling constant anomalies in substituted ß-lactams.

ABSTRACT

ß-lactams are a chemically diverse group of molecules with a wide range of biological activities. Having recently observed curious trends in 2JHH coupling values in studies on this structural class, we sought to obtain a more comprehensive understanding of these diagnostic NMR parameters, specifically interrogating 1JCH, 2JCH, and 2JHH, to differentiate 3- and 4-monosubstituted ß-lactams. Further investigation using computational chemistry methods was employed to explore the geometric and electronic origins for the observed and calculated differences between the two substitution patterns.