Bipiperidinyl 4-ANPP (N-phenyl-1′-(2-phenylethyl)-[1,4′-bipiperidin]-4-amine) is an analytical reference standard that is structurally similar to known opioids.
Bipiperidinyl 4-ANPP is a byproduct in the synthesis of fentanyl.
See September 2022 NFLIS Report