Abstract N-Desmethyl-loperamide and loperamide were synthesized from α, α-diphenyl-γ- butyrolactone and 4-(4-chlorophenyl)-4-hydroxypiperidine in five and four steps with 8% and 16% overall yield, respectively. The amide precursor was synthesized from 4-bromo-2, 2- diphenylbutyronitrile and 4-(4-chlorophenyl)-4-hydroxypiperidine in 2 steps with 21–57% overall yield.[11 C] N-Desmethyl-loperamide and [11 C] loperamide were prepared from ...
