4'-methyl-α-pyrrolidinobutiophenone 4'-methyl-α-pyrrolidinobutiophenone 4'-methyl-α-pyrrolidinobutiophenone or mpbp is a stimulant compound which has been reported as a novel designer drug. it is closely related to pyrovalerone, being simply its chain-shortened homologue. 4'-methyl-α-pyrrolidinobutiophenonelegal statuslegal status ca: schedule i de: npsg (industrial and scientific use only) uk: class b identifiers iupac name (rs)-1-(4-methylphenyl)-2-(1-pyrrolidinyl)-1-butanone cas number732180-91-5pubchem cid57486975chemspider52084421uniib1gb3u8ygmchemical and physical dataformulac15h21nomolar mass231.339 g·mol−13d model (jsmol)interactive imagechiralityracemic mixture smiles c1cccn1c(cc)c(=o)c(cc2)ccc2c inchi inchi=1s/c15h21no/c1-3-14(16-10-4-5-11-16)15(17)13-8-6-12(2)7-9-13/h6-9,14h,3-5,10-11h2,1-2h3key:nxnpgaazkydopw-uhfffaoysa-n