the near-infrared (NIR) wavelength range of 700–900 nm has been reported for the imaging of elastic fibers. Here, we report the discovery of a NIR zwitterionic elastin probe ElaNIR (elastin NIR) through fluorescent-image-based screening. The probe was successfully applied for in vitro, ex vivo, and in vivo imaging by various imaging modalities. Age-related elastin differences shown by in vivo fluorescent
L-Threonine was transformed, stereospecifically, to a versatile β-lactam (5a) in 3 steps. This β-lactam was further converted to a key intermediate (25) for the synthesis of thienamycin and its biologically active analogues. Furthermore, the compound 5a was changed to iodides (18 and 23), cyanides (19 and 24), chloromethylketone (26) and aldehydes (30 and 31) which appear to have a latent potential