The pyrovalerones are basically the fentanyl of meth. More potent, shorter lasting, more dangerous.
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrovalerone
"Pyrovalerone is a DEA Schedule V controlled substance. Substances in the DEA Schedule V have a low potential for abuse relative to substances listed in Schedule IV and consist primarily of preparations containing limited quantities of certain narcotics."