N-Fmoc-D-Thr(OtBu)-4,4,4-d3-OH is labelled N-Fmoc-D-Thr(OtBu) which is derivative of D-Threonine (T405525). D-Threonine is the unnatural isomer of L-Threonine (T405500) and is known to inhibit growth and cell wall synthesis of Mycobacterium smegmatis. D-Threonine is also used as a synthetic intermediate for the production of chiral antibiotics.