General methodology for the chemoselective N-alkylation of (2,2,6,6)-tetramethylpiperidin-4-ol: Contribution of microwave irradiation

Abstract

A convenient method to access a broad variety of N-alkyl-(2,2,6,6)-tetramethylpiperidin-4-ol compounds is reported. The thermal treatment of a mixture of (2,2,6,6)-tetramethylpiperidin-4-ol and allyl or benzyl bromide derivatives gave the corresponding N-alkylated compounds in good yields while leaving the hydroxyl functional group intact. Whereas 40 h were needed to reach complete conversion, microwave irradiation allowed the reaction time to be reduced (20 min) and improved the yields in most cases.

Platinum–(phosphinito–phosphinous acid) complexes as bi-talented catalysts for oxidative fragmentation of piperidinols: an entry to primary amines

“…Having established the feasibility of the oxidation-opening sequence, we synthesized various N -alkyl-2,2,6,6-tetramethylpiperidin-4-ols 1b–q to extend its applicability. 28,29 Under optimized conditions, the conversion of 1 proceeded cleanly and the amines 4 were obtained in good to excellent yields without chromatography ( Scheme 3 ). All benzylic amines were obtained in very good yields whatever is the substitution on the phenyl ring ( Scheme 3 , 4b–4j).…”

“…As N-alkyl-2,2,6,6tetramethylpiperidin-4-ols are easily accessible from the cheap 2,2,6,6-tetramethylpiperidin-4-ol, 28 this cascade reaction sequence provides an interesting entry to aliphatic primary amines merely isolated aer simple acid-base extraction. Finally, the generated phorone 3 could readily be recycled into 2,2,6,6-tetramethylpiperidin-4-ol by reacting with ammonia and the method is practicable on a large scale (see ESI †).…”

“…The self-assembled negatively charged structure of the ligand may ease the abstracting hydrogen step from 1 while the metal cationic centre may promote the formation of amino–platinum complex species from 2 responsible fora Hofmann-type degradation so as to afford a primary amine 4. As N -alkyl-2,2,6,6-tetramethylpiperidin-4-ols are easily accessible from the cheap 2,2,6,6-tetramethylpiperidin-4-ol, 28 this cascade reaction sequence provides an interesting entry to aliphatic primary amines merely isolated after simple acid–base extraction. Finally, the generated phorone 3 could readily be recycled into 2,2,6,6-tetramethylpiperidin-4-ol by reacting with ammonia and the method is practicable on a large scale (see ESI † ).…”

Synthesis, Spectroscopic, Computational, Biological and Molecular docking studies on 3‐allyl 2,6‐diaryl piperidin‐4‐ones

“…[1][2][3] Commonly nitrogenbased heterocyclic compounds have biological activities, [4][5][6] particularly piperidine moieties that were synthesised using a variety of techniques with and without catalysts. [7][8][9] Saturated piperidin-4-one's nucleus is present in many alkaloids and synthetic drugs. [10] Specially 2,6-diaryl substituted piperidin-4-one molecules were previously studied for their medicinal and pharmacological properties, like Anti-tumour, [11,12] antioxidant, [13] anti-cancer, [14] anti-proliferative, [15] DNA bindings, [16] and Anti-microbialstudies.…”

“…Similar to the preparation of a highly functionalized heterocyclic compound, multicomponent reactions are the primary techniques [1–3] . Commonly nitrogen‐based heterocyclic compounds have biological activities, [4–6] particularly piperidine moieties that were synthesised using a variety of techniques with and without catalysts [7–9] . Saturated piperidin‐4‐one's nucleus is present in many alkaloids and synthetic drugs [10] .…”