Editing Fentanyl (section)

=== Siegfried ===
[[File:NPP to fentanyl.svg|class=skin-invert-image|thumb|Siegfried method from NPP through 4-ANPP to fentanyl]]
The Siegfried method, initially described in 1978 and later published on [[The Hive (website)|The Hive]], involves the initial synthesis of [[N-phenethyl-4-piperidone|''N''-phenethyl-4-piperidone]] (NPP).<ref>{{cite journal | vauthors = Weedn VW, Elizabeth Zaney M, McCord B, Lurie I, Baker A | title = Fentanyl-related substance scheduling as an effective drug control strategy | journal = Journal of Forensic Sciences | volume = 66 | issue = 4 | pages = 1186–1200 | date = July 2021 | pmid = 33951192 | pmc = 8360110 | doi = 10.1111/1556-4029.14712 }}</ref> This intermediate is [[Reductive amination|reductively aminated]] to [[4-anilino-N-phenethylpiperidine|4-anilino-''N''-phenethylpiperidine]] (4-ANPP). Fentanyl is produced following the reaction of 4-ANPP with an acyl chloride.<ref>{{cite web |title=Synthesis of Fentanyl |url=https://erowid.org/archive/rhodium/chemistry/fentanyl.html |website=Rhodium |publisher=Siegfried |access-date=24 January 2023 |archive-date=5 August 2022 |archive-url=https://web.archive.org/web/20220805104925/https://www.erowid.org/archive/rhodium/chemistry/fentanyl.html |url-status=live }}</ref> The Siegfried method was used in the early 2000s to manufacture fentanyl in both domestic and foreign clandestine laboratories.<ref>{{cite web |title=Designation of Benzylfentanyl and 4-Anilinopiperidine, Precursor Chemicals Used in the Illicit Manufacture of Fentanyl, as List I Chemicals |url=https://www.federalregister.gov/documents/2020/04/15/2020-07064/designation-of-benzylfentanyl-and-4-anilinopiperidine-precursor-chemicals-used-in-the-illicit |website=Federal Register |access-date=28 January 2023 |date=15 April 2020 |archive-date=5 November 2021 |archive-url=https://web.archive.org/web/20211105125231/https://www.federalregister.gov/documents/2020/04/15/2020-07064/designation-of-benzylfentanyl-and-4-anilinopiperidine-precursor-chemicals-used-in-the-illicit |url-status=live }}</ref>