1-Methyl-2-piperidinone 1-Methyl-2-piperidone 1-Methylpiperidine-2-one 2-Piperidinone, 1-methyl- 2-Piperidone, 1-methyl- 5-21-06-00398 (Beilstein Handbook Reference) 931-20-4 AI3-11535 BRN 0001708 EINECS 213-231-9 N-METHYL-2-PIPERIDINONE N-Methyl-2-piperidone N-Methylvalerolactam NSC 67384