drug analysis drug synthesis 5 radioisotope theoretical study 5 in vitro study 4 drug identification 3 infrared spectrometry 3 mass spectrometry 3 preliminary communication 3 Synthesis 2 thin layer chromatography 2 20 hydroxy 3 oxo 23 norchol 4 enoic acid c 14 1 3 oxo 23 norchola 4,20(22) dienoic acid c 14 1 3beta hydroxy 23 norchol 20(22) enoic acid c 14 1 3beta hydroxy 23 norchola 5,20(22) dienoic acid c 14 1 3beta hydroxy 5beta cholanoic acid c 14 1 3beta hydroxychol 5 enoic acid c 14 1 3beta,20 dihydroxy 23 norchol 5 enoic acid c 14 1 3beta,20 dihydroxy 23 norcholanic acid c 14 1 5beta pregnan 3beta ol 20 one c 14 1 Ethyl |1‐14C| bromoacetate 1 Hordenine‐α‐14C 1 Reformatsky reaction 1 Tyramine‐α‐14C 1 hordenine c 14 1 nonhuman 1 nuclear magnetic resonance 1 oxaloacetic acid c 14 1 priority journal 1 tyramine c 14 1