The reaction is catalysed with weak base like piperidine or pyridine. Sodium amide will also deprotonate indole and piperidine. Calixarenes also form exo-calix ammonium salts with aliphatic amines such as piperidine. Phenylpiperidine is a chemical compound with a phenyl moiety directly attached to piperidine. Thus, piperidine and tetrahydrofuran are conventional amines and ethers, with modified steric profiles. It is a carboxylic acid of piperidine. Both men obtained piperidine by reacting piperine with nitric acid. Pharmaceuticals that can produce piperidine alkaloids, pentacyclic terpenoids, and anthraquinones. Methylphenidate is a central nervous system (CNS) stimulant of the phenethylamine and piperidine classes. Enamines derived from piperidine can be used in the Stork enamine alkylation reaction. The piperidine structural motif is present in numerous natural alkaloids. It has a 3,5-bistrifluoromethyl benzylether piperidine in place of 2-methoxy benzylamine moiety of CP-99994 compound. Regular achiral organocatalysts are based on nitrogen such as piperidine used in the Knoevenagel condensation. Fire ants, "Solenopsis" spp., are unique in having a venom sac containing piperidine alkaloids. Calcium hypochlorite converts piperidine to "N"-chloropiperidine.