Figure 2.

Overview of experimentally determined proton–proton distances that were used to determine the solution conformations of PROTACs 1–3. Red arrows indicate long-range NOEs between protons in the BRD4 and CRBN ligands, while all other NOEs are indicated by blue arrows. Temperature coefficients (Δδ/T, ppb/K) for the NH protons of 1–3 in CDCl₃ are given in red adjacent to each NH proton. An absolute value for Δδ/T of <3 indicates the NH to be involved in a strong intramolecular hydrogen bond (IMHB) or shielded from the solvent, while larger values indicate that the environment of the NH varies with the temperature.³⁷ Atoms 2–5 have been labeled for PROTAC 3.