Zhao, Xuna’s team published research in Journal of Organic Chemistry in 82 | CAS: 219543-09-6

Zhao, Xuna published the artcileIn Situ Generated TEMPO Oxoammonium Salt Mediated Tandem Cyclization of β-Oxoamides with Amine Hydrochlorides for the Synthesis of Pyrrolin-4-ones, Computed Properties of 219543-09-6, the publication is Journal of Organic Chemistry (2017), 82(12), 6125-6132, database is CAplus and MEDLINE.

In the presence of TEMPO (via its in situ-generated oxoammonium salt), acetoacetamides MeCOCH₂CONHR (R = Ph, 4-MeOC₆H₄, 3-MeOC₆H₄, 2-MeOC₆H₄, 4-MeC₆H₄, 2-MeC₆H₄, 2,4-Me₂C₆H₃, 4-ClC₆H₄, 3-ClC₆H₄, 2-ClC₆H₄, 4-EtO₂CC₆H₄, PhCH₂, t-Bu) underwent chemoselective oxidative cyclocondensations with amine hydrochlorides R¹NH₂·HCl (R¹ = Ph, 4-MeOC₆H₄, 4-MeC₆H₄, 3-MeC₆H₄, 2-MeC₆H₄, 4-ClC₆H₄, 3-ClC₆H₄, HCCCH₂, PhCH₂, n-Pr, H) or ammonium chloride in DMF to yield oxopyrroledicarboxamides I (R = Ph, 4-MeOC₆H₄, 3-MeOC₆H₄, 2-MeOC₆H₄, 4-MeC₆H₄, 2-MeC₆H₄, 2,4-Me₂C₆H₃, 4-ClC₆H₄, 3-ClC₆H₄, 2-ClC₆H₄, 4-EtO₂CC₆H₄, PhCH₂, t-Bu; R¹ = Ph, 4-MeOC₆H₄, 4-MeC₆H₄, 3-MeC₆H₄, 2-MeC₆H₄, 4-ClC₆H₄, 3-ClC₆H₄, HCCCH₂, PhCH₂, n-Pr, H) in 48-82% yields. Detailed mechanistic studies disclosed that TEMPO oxoammonium salt generated in situ was crucial for the transformation involving the formation of enaminone precursors in situ by condensation of the β-oxoamides with amines, followed by sequential oxidative coupling with β-oxoamides, intramol. cyclization, and 1,2-alkyl migration steps.

Journal of Organic Chemistry published new progress about 219543-09-6. 219543-09-6 belongs to piperidines, auxiliary class Piperidine,Fluoride,Salt,Amine,Amide, name is 4-Acetamido-2,2,6,6-tetramethyl-1-oxopiperidinium Tetrafluoroborate, and the molecular formula is C7H10O4, Computed Properties of 219543-09-6.

Referemce:
https://en.wikipedia.org/wiki/Piperidine,
Piperidine | C5H11N – PubChem