Thalidomide -5-propargyl is a propargyl-modified Thalidomide , that acts as a Cereblon ligand to recruit CRBN proteins. Thalidomide -5-propargyl use alkynyl group at the end to be directly used in the synthesis of triazoles in the synthesis of PROTAC molecules, and is a key intermediate in the synthesis of PROTAC molecules based on CRBN design.