Figure 2
From: Alterations to the broad-spectrum formin inhibitor SMIFH2 modulate potency but not specificity
SMIFH2 is a mix of isomers that equilibrate over time. 1H NMR spectra of the same sample were collected at two time points. The blue spectrum (bottom) corresponds to the SMIFH2 sample immediately after preparation in THF-d8. The uneven peak integrations are evident in the signals for protons A, B, C, D and E. The initial isomeric ratio was calculated as 3.5:1 by integration of major resonance at 8.25 ppm and minor resonance at 8.33 ppm for proton E. After 20 h at 25 °C (red spectrum; top), the peak integrations were similar for each isomer, reflecting equilibration to a ≈1:1 E:Z mixture (isomeric ratio 1.1:1 by integration of resonances at 8.33 ppm and 8.25 ppm).
