SEARCH Articles Figures Tables 1 -methyl-4-piperidyl 2- Indolyl 4-piperidyl ketone Alkaloids related to 20-piperidyl-5a-pregnane N-Ethyl-3-piperidyl benzilate N-Methyl-3-piperidyl benzilate N-Methyl-4-piperidyl Phenyl piperidyl ketone Piperidyl glycolates