Certain compounds and pharmaceutically acceptable salts are provided herein. Also provided are pharmaceutical compositions comprising at least one compound or pharmaceutically acceptable salt therein and one or more pharmaceutically acceptable vehicle. Methods of treating patients suffering from certain disease states responsive to the inhibition of transglutaminase TG2 activity are described. These disease states include neurodegenerative disorders such as Huntington's disease. Also described are methods of treatment include administering at least one compound or pharmaceutically acceptable salt thereof as a single active agent or administering at least one compound or pharmaceutically acceptable salt thereof in combination with one or more other therapeutic agents.