Chemistry of Hindered Amines from the Piperidine Series

Dagonneau, M.; Каган, Е. Ш.; Михайлов, В. И.; Rozantsev, É. G.; Sholle, V. D.

doi:10.1055/s-1984-31014

Cited by 38 publications

(10 citation statements)

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“…Consequently, several generations of chemists have designed a variety of synthetic methods over the years. The same holds true for sterically hindered amines, for which wide ranges of applications were found, for example, as bases with low nucleophilicity, such as 1 and 2 , or precursors of persistent nitroxyl radicals, like 3 , utilized for spin labeling tools (Figure ). Numerous 2,2,6,6-tetramethylpiperidines of type 4 and free radicals derived from these heterocycles are polymerization inhibitors and thermo- and photostabilizers, known as hindered amine light stabilizers (HALS) .…”

Section: Introductionmentioning

confidence: 84%

Steric Hindrance Underestimated: It is a Long, Long Way to Tri-tert-alkylamines

et al. 2018

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Ten different processes (Methods A-J) were tested to prepare tertiary amines bearing bulky alkyl groups. In particular, S1 alkylation of secondary amines with the help of 1-adamantyl triflate (Method D) and reaction of N-chlorodialkylamines with organometallic reagents (Method H), but also attack of the latter reagents at iminium salts, which were generated in situ by N-alkylation of imines (Method J), led to trialkylamines with unprecedented steric congestion. These products showed a restriction of the rotation about the C-N bond. Consequently, equilibration of rotamers was slow on the NMR time scale resulting in distinguishable sets of NMR data at room temperature. Furthermore, tertiary amines with bulky alkyl substituents underwent Hofmann-like elimination when heating in toluene to form an olefin and a secondary amine. Since the tendency to take part in this decay reaction correlated with the degree of steric hindrance around the nitrogen atom, Hofmann elimination at ambient temperature, which made the isolation of the tertiary amine difficult, was observed in special cases.

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Section: Introductionmentioning

confidence: 84%

Steric Hindrance Underestimated: It is a Long, Long Way to Tri-tert-alkylamines

et al. 2018

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“…Similarly, the anion of 2 reacted with racemic styrene oxide to give, after hydrolysis, alcohol 7 as two diastereomers (Scheme 4). In both cases, HMPT was added in order to promote the C-alkylation over a competing piperidine alkylation [2] or alkylation of LDA. Both the alkylation with methyl iodide and with styrene oxide were performed in ether/HMPT in order to test the suitability of diethyl ether as solvent, though THF is clearly expected to be the better solvent for a high nucleophilictiy of the imine anion.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of 3-alkylated triacetonamine derivatives

Sensfuß

Habicher

1999

J. prakt. Chem.

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Reaction of a lithiated imine derivative of 2,2,6,6‐tetramethyl‐4‐piperidone (triacetonamine, 1) with activated or less reactive alkyl halides or styrene oxide and subsequent hydrolysis afforded 3‐alkylated triacetonamine derivatives. Thus, 3‐benzyl‐2,2,6,6‐tetramethyl‐4‐piperidone (3), 3‐(n‐butyl)‐2,2,6,6‐tetramethyl‐4‐piperidone (4), 3‐(3‐chloropropyl)‐2,2,6,6‐tetramethyl‐4‐piperidone (5), 2,2,3,6,6‐pentamethyl‐4‐piperidone (6) and two diastereomers of 3‐(2‐hydroxy‐2‐phenylethyl)‐2,2,6,6‐tetramethyl‐4‐piperidone (7) were prepared in 26–53% yield. Reaction of the imine anion derived from 1 with benzyl bromide to give 3 has to be performed at low temperatures in order to avoid a competing proton transfer. No reaction at the unprotected piperidine nitrogen was observed.

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“…A Preparation of compounds (5) and (6) Compound 2 (0.01 mole) is refluxed with sodium azide (0.01 mole) in 5 mL acetic acid and 4 drops of water for 15 minutes. The precipitate formed is filtered, dried and crystallized from benzene to afford compound 5.…”

Section: -( H Y D R O X Y M E T H O X Y ) -2 2 6 6tetramethylpimentioning

confidence: 99%

“…2,2,6,6-Tetramethyl-piperidine derivatives have different biological effects. 2,2,6,6-Tetramethyl-piperidine derivatives have anticancer, analgesic, antipyretic and anticholinergic effects [4,5]. Also, 2,2,6,6-tetramethyl-piperidin-4-one have hypotensive and vasodilator activity as demonstrated by intravital microcirculation method [6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Reactions, and Antimicrobial activity of N-Hydroxy-triacetonamine Derivatives

2019

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S IMPLE and one step method for preparation of N-hydroxy-2,2,6,6-tetramethyl-4-piperidone is reported. N-Hydroxy-2,2,6,6-tetramethyl-4-piperidone (1) reacts with formaldehyde, formaldehyde and piperidine to afford compounds (3) and (4) respectively. Compound (1) reacts with sodium azide and α-bromosugar to afford corresponding products. Compound (1) reacts with 2-(4-chlorobenzylidene)malononitrile to afford 1,6-napthyridine derivative (9). N-Hydroxy-2,2,6,6-tetramethyl-4-piperidone (1) reacts with p-chlorobenzaldehyde and cyanoacetamide to produce 1,6-napthyridine derivative (10a). N-Hydroxy derivative (1) reacts also with p-chlorobenzaldehyde and ethylcyanoacetate to afford 1,6-napthyridine (10b). Antimicrobial screening of some of the synthesized compounds has been performed.

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Chemistry of Hindered Amines from the Piperidine Series

Cited by 38 publications

References 0 publications

Steric Hindrance Underestimated: It is a Long, Long Way to Tri-tert-alkylamines

Steric Hindrance Underestimated: It is a Long, Long Way to Tri-tert-alkylamines

Synthesis of 3-alkylated triacetonamine derivatives

Synthesis, Reactions, and Antimicrobial activity of N-Hydroxy-triacetonamine Derivatives

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