7031-93-8

Basic information

• Product Name: 1-Hydroxy-2,2,6,6-tetramethylpiperidine
• Synonyms: 1-Hydroxy-2,2,6,6-tetramethylpiperidine;2,2,6,6-Tetramethylpiperidin-1-ol;Piperidine, 1-hydroxy-2,2,6,6-tetramethyl-
• CAS NO: 7031-93-8
• Molecular Formula: C₉H₁₉NO
• Molecular Weight: 157.25326
• Mol File: 7031-93-8.mol
• Article Data: 101

Chemical Properties

• Melting Point: 39-40 °C
• Boiling Point: 208.8±7.0 °C(Predicted)
• Appearance: /
• Density: 0.917±0.06 g/cm3(Predicted)
• Storage Temp.: under inert gas (nitrogen or Argon) at 2-8°C
• PKA: 14.28±0.60(Predicted)
• CAS DataBase Reference: 1-Hydroxy-2,2,6,6-tetramethylpiperidine(CAS DataBase Reference)
• NIST Chemistry Reference: 1-Hydroxy-2,2,6,6-tetramethylpiperidine(7031-93-8)
• EPA Substance Registry System: 1-Hydroxy-2,2,6,6-tetramethylpiperidine(7031-93-8)

Safety Data

• Hazardous Substances Data: 7031-93-8(Hazardous Substances Data)

Usage

Uses

2,2,6,6-Tetramethyl-1-hydroxypiperidine is a reactant used in various synthesis and investigations. It was used as a reactant in the study of predicting organic hydrogen atom transfer rate constants using the Marcus cross relation. 2,2,6,6-Tetramethyl-1-hydroxypiperidine was also used as a reactant in the preparation of ammonia from an iron nitrido complex.

Upstream product

• 26864-01-7 2,2,6,6-tetramethylpiperidin-1-oxoammonium chloride 
• 121-69-7 N,N-dimethyl-aniline 
• 768-66-1 2,2,6,6-tetramethyl-piperidine 
• 154554-67-3 1-phenyl-1-(2',2',6',6'-tetramethyl-1'-piperidinyloxy)ethane 
• 2403-88-5 4-hydroxy-2,2,6,6-tetramethylpiperidine 
• 107-05-1 3-chloroprop-1-ene 
• 2564-83-2 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical 
• 211562-21-9 sodium 2,2,6,6-tetramethylpiperidine-1-oxide 
• 2564-83-2 2,2,6,6-tetramethyl-piperidine-N-oxyl 
• 102-54-5 ferrocene 
• 7664-41-7 ammonia 
• 185154-27-2 bis(η5-tetramethyl(trimethylsilyl)cyclopentadienyl)titanium(III) chloride 
• 122-66-7 diphenyl hydrazine 
• 178626-04-5 3-phenyl-1-(2′,2′,6′,6′-tetramethyl-1′-piperidinyloxy)-propane 

Downstream Products

• 34672-84-9 1-methoxy-2,2,6,6-tetramethylpiperidine 
• 270901-56-9 2-(2,2,6,6-tetramethylpiperidin-1-yloxy)hept-6-enenitrile 
• 270901-39-8 2,2,6,6-tetramethyl-1-(1-phenylhex-5-enoyloxy)piperidine 
• 270901-53-6 2,2,6,6-tetramethyl-1-(1-(2-thienyl)hex-5-enyloxy)piperidine 
• 270901-54-7 2,2,6,6-tetramethyl-1-(1-(2-pyridyl)hex-5-enyloxy)piperidine 
• 270901-51-4 2,2,6,6-tetramethyl-1-(1-(4-bromophenyl)hex-5-enyloxy)piperidine 
• 270901-52-5 2,2,6,6-tetramethyl-1-(1-(4-methoxyphenyl)hex-5-enyloxy)piperidine 
• 1003017-40-0 [Ru(II)(1,1,1-5,5,5-hexafluoro-2,4-pentanedionato)2(2-(2'-pyridyl)imidazole)] 
• 868139-71-3 (tetraphenylporphyrin)Fe(II)(4-methylimidazole)2 
• 3637-11-4 1-hydroxy-2,2,6,6-tetramethyl-piperidin-4-one 
• 2564-83-2 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical 
• 10531-39-2 N,N-di-tert-butylhydroxylamine 
• 1227569-07-4 dithiocarbonic acid acid S-methyl ester S-(2,2,6,6-tetramethylpiperidin-1-yl) 
• 1309607-01-9 Ph₃PC(H)C(=O)ON(C₅H₆(CH₃)4) 

Relevant articles and documents

Electron-rich phenoxyl mediators improve thermodynamic performance of electrocatalytic alcohol oxidation with an iridium pincer complex

Electron-rich phenols, including α-rac-tocopherol Ar1OH, 2,4,6,-tri-tert-butylphenol Ar3OH, and butylated hydroxy-toluene Ar4OH, are effective electrochemical mediators for the electrocatalytic oxidation of alcohols by an iridium amido dihyride complex (PNP)Ir(H)2 (IrN 1, PNP = bis[2-diisopropylphosphino)ethyl]amide). Addition of phenol mediators leads to a decrease in the onset potential of catalysis from -0.65 V vs Fc+/0 under unmediated conditions to -1.07 V vs Fc+/0 in the presence of phenols. Mechanistic analysis suggests that oxidative turnover of the iridium amino trihydride (PNHP)Ir(H)3 (IrH 2, PNHP = bis[2-diisopropylphosphino)ethyl]amine) to IrN 1 proceeds through two successive hydrogen atom transfers (HAT) to 2 equiv of phenoxyl that are generated transiently at the anode. Isotope studies and comparison to known systems are consistent with initial homolysis of an Ir-H bond being rate-determining. Turnover frequencies up to 14.6 s-1 and an average Faradaic efficiency of 93% are observed. The mediated system shows excellent chemoselectivity in bulk oxidations of 2-propanol and 1,2-benzenedimethanol in THF and is also viable in neat 2-propanol.

Visible-light unmasking of heterocyclic quinone methide radicals from alkoxyamines

In nature, the unmasking of heterocyclic quinones to form stabilized quinone methide radicals is achieved using reductases (bioreduction). Herein, an alternative controllable room-temperature, visible-light activated protocol using alkoxyamines and bis-alkoxyamines is provided. Selective synthetic modification of the bis-alkoxyamine, allowed chromophore deactivation to give one labile alkoxyamine moiety.

Synthesis and characterization of novel type poly (4-chloromethyl styrene-grft-4-vinylpyridine)/TiO2 nanocomposite via nitroxide-mediated radical polymerization

This paper describes the synthesis and characterization of novel type poly (4-chloromethyl styrene-graft-4-vinylpyridine)/TiO2 nanocomposite. Firstly, poly (4-chloromethyl styrene)/TiO2 nanocomposite was synthesized by in situ free radical polymerizing of 4-chloromethyl styrene monomers in the presence of 3-(trimethoxysilyl) propylmethacrylate (MPS) modified nano-TiO2. Thereafter, 1-hydroxy-2,2,6,6-tetramethyl-1- piperidinyloxy (TEMPO-OH) was synthesized by the reduction of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO). This functional nitroxyl compound was covalently attached to the poly (4-chloromethyl styrene)/TiO2 with replacement of chlorine atoms in the poly (4-chloromethyl styrene) chains. The controlled graft copolymerization of 4-vinylpyridine was initiated by poly (4-chloromethyl styrene)/TiO2 nanocomposite carrying TEMPO groups as a macroinitiators. The coupling of TEMPO with poly (4-chloromethyl styrene)/TiO2 was verified using 1H nuclear magnetic resonance (NMR) spectroscopy. The obtained nanocomposites were studied using transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and the optical properties of the nanocomposites were studied using ultraviolet-visible (UV-Vis) spectroscopy.

Mechanistic studies of the reaction of Ir (III) porphyrin hydride with 2,2,6,6-tetramethylpiperidine-1-oxyl to an unsupported Ir-Ir porphyrin dimer

Reaction of hydrido[5,10,15,20-tetrakis(p-tolyl)porphyrinato]iridium(III) (Ir(ttp)H) (1) with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) (2) at room temperature gave a 90% yield of the unsupported iridium(II) porphyrin dimer, IrII2(ttp)2 (3). Kinetic measurements revealed that the oxidation followed overall second-order kinetics: rate = k[Ir(ttp)H][TEMPO], k(25 °C) = 6.65 × 10-4M-1. The entropy of activation (ΔS? = -25.3 ± 2.5 calmol-1 K-1)and the kinetic isotope effect of 7.2 supported a bimolecular associative mechanism in the rate-determining hydrogen atom transfer from Ir(ttp)H to TEMPO.

Titration of nitroxide free radicals by nuclear magnetic relaxometry

An alternative to electron spin resonance spectroscopy is proposed for the quantitative analysis of nitroxide free radicals in solution. The method is based on the chemical reduction of the paramagnetic compounds followed by NMR measurements of the longitudinal relaxation rate of the solvent protons. This titration of the nitroxides has been carried out in ethanolic solutions by reaction with known amounts of phenylhydrazine. The paramagnetic fraction of the solvent relaxation rate is precisely related to the concentration of the free radical which can be measured without prior knowledge of its specific influence on the protons relaxation rate (relaxivity). Oxygen has to be eliminated from the solutions in order to avoid reoxidation of the hydroxylamine formed. The precision of the method, tested on 11 diversely subsituted derivatives of piperidine-1-oxyl, pyrrolidine-1-oxyl, and 3-oxazolidine-1-oxyl, offers a precision of about 3%.

Single crystal to single crystal transformation and hydrogen-atom transfer upon oxidation of a cerium coordination compound

Trivalent and tetravalent cerium compounds of the octamethyltetraazaannulene (H2omtaa) ligand have been synthesized. Electrochemical analysis shows a strong thermodynamic preference for the formal cerium(IV) oxidation state. Oxidation of the cerium(III) congener Ce(Homtaa)(omtaa) occurs by hydrogen-atom transfer that includes a single crystal to single crystal transformation upon exposure to an ambient atmosphere.

Homolytic Reactivity of Group 14 Organometallic Hydrides toward Nitroxides

The spontaneous reactions of Et3SiH, Ph3GeH, Bu3SnH, and (Me3Si)3SiH with 2,2,6,6-tetramethyl1-piperidinoxyl (TEMPO) and related nitroxides have been investigated. Metal hydrides characterized by relatively weak metal-hydrogen bonds, like Ph3GeH and Bu3SnH, reduce TEMPO to the corresponding hydroxylamine while no reaction is observed with Et3SiH and Ph3SiH. Tris(trimethylsilyDsilane, on the other hand, is able to reduce the nitroxide to the corresponding hydroxylamine and amine in a ca. 1:1 ratio. By repeating the above reactions in the presence of thermal or photochemical radical initiators, deoxygenation of TEMPO was obtained in high yield with (Me3SD)3SiH and (Me3Si)2Si(H)Me, but not with other silanes, germanes, and stannanes. A mechanism for the reduction of TEMPO by the two trimethylsilyl-substituted silanes is proposed, and kinetic data for the various steps of the overall reaction are reported. In particular rate constants and activation parameters have been measured for the hydrogen transfer reaction from several silanes to the hindered aminyl radical 2,2,6,6-tetramethylpiperidinyl.

Homoleptic Rhodium Pyridine Complexes for Catalytic Hydrogen Oxidation

The homoleptic rhodium pyridine complex [Rh(py)4]+([1]+) is prepared from simple precursors. Lacking good π-acceptor ligands but being sterically protected, [1]+reversibly oxidizes to colorless [Rh(py)4(thf)2]2+. This monomericS= 1/2 Rh(II) complex activates H2to give [HRh(py)4L]2+, which can also be generated by protonation of [1]+. The Rh(III)-H bond is weak, being susceptible to H atom abstraction as well as deprotonation. These results underpin a novel catalytic system for the oxidation of H2by ferrocenium.

Non-Heme-Iron-Mediated Selective Halogenation of Unactivated Carbon?Hydrogen Bonds

Oxidation of the iron(II) precursor [(L1)FeIICl2], where L1 is a tetradentate bispidine, with soluble iodosylbenzene (sPhIO) leads to the extremely reactive ferryl oxidant [(L1)(Cl)FeIV=O]+ with a cis disposition of the chlorido and oxido coligands, as observed in non-heme halogenase enzymes. Experimental data indicate that, with cyclohexane as substrate, there is selective formation of chlorocyclohexane, the halogenation being initiated by C?H abstraction and the result of a rebound of the ensuing radical to an iron-bound Cl?. The time-resolved formation of the halogenation product indicates that this primarily results from sPhIO oxidation of an initially formed oxido-bridged diiron(III) resting state. The high yield of up to >70 % (stoichiometric reaction) as well as the differing reactivities of free Fe2+ and Fe3+ in comparison with [(L1)FeIICl2] indicate a high complex stability of the bispidine-iron complexes. DFT analysis shows that, due to a large driving force and small triplet-quintet gap, [(L1)(Cl)FeIV=O]+ is the most reactive small-molecule halogenase model, that the FeIII/radical rebound intermediate has a relatively long lifetime (as supported by experimentally observed cage escape), and that this intermediate has, as observed experimentally, a lower energy barrier to the halogenation than the hydroxylation product; this is shown to primarily be due to steric effects.

TEMPO-Mediated Cross-Dehydrogenative Coupling of Indoles and Imidazo[1,2- a]pyridines with Fluorinated Alcohols

A simple and highly efficient metal-free method has been developed for hydroxyfluoroalkylation of indoles and imidazo[1,2-a]pyridines via TEMPO-mediated C(sp3)-H and C(sp2)-H bond cross-dehydrogenative coupling of fluorinated alcohols and indoles. The protocol showed broad substrate scope, afforded good yields of hydroxyfluoroalkylated products, and was amenable for scale-up. Mechanistic investigation indicated involvement of the radical pathway.