20S Proteasome-IN-4 (Compound 7) is a brain-penetrant, parasite-selective, orally active 20S proteasome inhibitor with an IC 50 of 6.3 nM against T. b. brucei 20S proteasome. 20S Proteasome-IN-4 can be used for the research of human African trypanosomiasis (HAT).