1 -Amino-2,2,6,6-tetramethylpiperidine

A series of isodiazene complexes has been derived from 1-amino-2,2,6,6-tetramethylpiperidine... 

Allen, N.S., Edge, M., He, J., Chen, W., Kikkawa, K., Minagawa, M. Thermal and photooxidative behaviour of 2-hydroxybenzophenone stabilisers in polyolefin films Effeet of 4-butoxy-4-amino-tetramethylpiperidine substitution. Polym. Degrad. Stab. 42, 293-306 (1993)... 

This blend was obtained by polymers mixture extrusion and extraction with the azeotropic mixture of hexane/ethanol, and modifying the obtained polymer surface by coupling of 4-isocyanato butanoic acid methyl ester (as a spacer molecule) to PVA blend, saponification of methyl ester groups and coupling of 4-amino-TEMPO (2,2,6,6-tetramethylpiperidine-l-oxyl) [229],... 

Spectroscopic techniques such as electron spin resonance (ESR) offer the possibility to "probe" the chemical environment of the interlayer regions. With the ESR technique, an appropriate paramagnetic ion or molecule is allowed to penetrate the interlayer, and chemical information is deduced from the ESR spectrum. Transition metal ions, such as Cu2+, and nitroxide radical cations, such as TEMPAMINE (4-amino-2,2,6,6-tetramethylpiperidine N-oxide) have been used as probes in this manner (6-14). Since ESR is a sensitive and non-destructive method, investigations of small quantities of cations on layer silicate clays at various stages... 

Amino-2,2,6,6-tetramethylpiperidine was reacted with EMME in ethanol at ambient temperature to yield (4-piperidinylamino)methylenemalo-nate (36) (77GEP2612314). 

Barriers to rotation of nitrosamines in which the amino part is embedded in a cyclic system seem generally to be smaller. However, Harris and associates (82) reported that the barrier of /V-nitroso-2,2,5,5-tetramethylpyrrolidine (43) was over 22.6 kcal/mol. This must be higher than the barrier required for isolation of rotamers at room temperature, and is even higher than that in /V-nitroso-2,2,6,6-tetramethylpiperidine (44). Harris and Pryce-Jones attribute the high barrier of 43 relative to 44 to the more stable ground state of the former. If the pyrrolidine derivative is properly substituted, the atropisomers are expected to be isolable at room temperature. 

The Dervan group discovered that addition of ferf-butyl hypochlorite to a solution of l-amino-2,2,6,6-tetramethylpiperidine and triethylamine in ether at —78 °C produces triethylammonium chloride as an insoluble white precipitate and an intense purple solution. The purple coloration, which is stable for hours at —78 °C, fades in minutes at 0 °C and was assigned to the 1,1-diazene 64. " " " ... 

In 1994, Osa and co-workers reported a very interesting means of obtaining chiral bi-naphthol based on electrocatalytic synthesis [139]. This work required the coating of the electrode with a poly(acrylic acid) (PAA) layer bonded via an amide connection to 4-amino-2,2,6,6-tetramethylpiperidin-l-yloxyl [91, 92]. (-)-Sparteine (208) was used as both the mediator and as a chiral agent (present in a stoichiometric amount) in the anolyte compartment. The yields and enantiomeric excesses obtained were excellent (Table 34). The complexity of... 

N- 2-[Bis-(2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-l-yloxy)-propionylamino]-propionylamino -ethyl)-amino]-ethyl-2-methyl-2-[2-(2,2,6,6,-tetramethylpiperidin-l-yloxy)-propionylamino]-propionamide... 

Electron paramagnetic resonance (EPR) and neutron diffraction can also be used to study molten salts. An example of the former is a study of the motion of large organics [2,2,6,6-tetramethylpiperidine-l-oxyl (tempo) and 4-amino tempo, or tem-pamine] dissolved in room-temperature molten salts, e.g., l-ethyl-3-methylimidazalo-... 

A polyadduct formed from aniline, phenothiazine, oxirane and 2,3-epoxypropane [145] was proposed as a component for the synthesis of a light stable PUR. A polyadduct of 4,4 -isopropylidenebisphenol with 2-hydroxy-4-(2,3-epoxypropyl)-benzophenone [131], polymeric HALS 115 formed from bis(2,3-epoxypropyl)ani-line and 4-amino-2,2,6,6-tetramethylpiperidine [146] or a brominated oligomer 116 used in combination with antimony trioxide as FR for PET [147] are other examples of polyaddition stabilizers. 

Electrochemical reduction of 2,2,6,6-tetramethyl-4-oxopiperidine (I) azine or a mixture of I and hydrazine at a lead cathode in neutral medium gave a nearly quantitative yield of 4-amino-2,2,6,6-tetramethylpiperidine II [49]. 

Gallc er and co-workers devised a formal enantioselective synthesis of ( — )-3 in wduch the stereogenic center at C-6 was derived fiom Cbz-protected (S)-2-amino-4-pentenoic acid (36) (44). Acylation of 3,3-dimethoxy-pyrrolidine (37) with this acid yielded amide 38, which was converted into aldehyde 39 by cleavage of the terminal alkene vnth osmium tetroxide and sodium periodate (Scheme 5). The indolizidine nucleus was constructed from 39 by a problematic intramolecular aldol condensation, which was eventually optimized by using 2,2,6,6-tetramethylpiperidine as base followed by adsorption onto, and elution from, silica gel (45). Diastereoselective reduction of the ketone group of the aldol product 40 was accomplished in better than 95% enantiomeric excess (ee) with the Corey... 

Conventionally, HAS are blended with PO during processing. 2-(Diethy-lamino)-4,6-bis[butyl(l,2,2,6,6-pentamethyl-4-piperidyl) amino]-l,3,5-triazine may be fed with an olefin directly into the low pressure polymerization process catalyzed with a modified MgCl2 supported Ziegler-Natta catalyst [142]. The catalytic activity was not impaired [143], Tetramethylpiperidine was reported to be a useful component in MgC -supported Ziegler-Natta catalysts as well. Very high stereospecificity of the synthesised PO was achieved. A complex of HAS with the alkyl aluminium activator was envisaged without interaction with the catalytically active alkyl titanium compound [144],... 

Great attention has been paid to HAS and their safety application in plastics and coatings. The 4-unsubstituted 2,2,6,6-tetramethylpiperidine is considered as relatively toxic, the acute oral toxicity being about 1 g/kg. The substitution in position 4 (i.e. the general mode in the synthesis of HAS for polymer purposes) dramatically improves the situation. Therefore, commercial HAS like 28 (R = H), 34,35a or 35b were approved for stabilization of packaging materials in contact with food [307]. Some data are available on properties of TEMPO (2,2,6,6-tetramethylpiperidinyl-l-oxyl) and its 4-amino or 4-hydroxy derivatives. They were found to act as weak intrinsic direct mutagens in Salmonella typhimurium. TEMPO increases intracellular hydroperoxide concentration. This may indicate its pro-oxidative effect which does not result, however, in cellular toxicity [314]. 

Triazine-2,4,6-triamine. N,N, N",N" -Tetrakis(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)-amino)triazin-2-yl)-4,7-diazadecane-1,10-diamine. Light and thermal stabilizer for PP fiber applications in automotive, marine and residential carpets, agricultural films, fertilizer bags, thick section pigmented applications, rotational molding applications. Ciba-Geigy Corp. 

Yeast tRNA, and 5S RNA from several species, have been spin-labelled at the 3 -terminus by oxidation with periodate, condensation with 4-amino-2,2,6,6-tetramethylpiperidin-l-oxyl, and reduction of the resulting product with borohydride. Analysis of the line shape variation of the e.s.r. spectra of the labelled molecules as a function of temperature reveals thermal unfolding transitions. ... 

As mentioned at the beginning of this section, Kirmse and coworkers (Bunse et al., 1992) found the first clear case of a homolytic aliphatic dediazoniation As shown in Scheme 7>24, the aqueous diazotization of 2>amino>2>methylpropane" nitrile (7.59) with two equivalents of NaN02 (or N2O4) yields products that are likely to be formed from the carbocation 7.60, namely 2>hydroxy-2-methylpropane-nitrile (7.62) and 2-methylprop-2-enenitrile (7.61), but also 2-methyl-2-nitropropane-nitrile (7.64), and the 7V,A-disubstituted 2>amino-2>methylpropanenitrile (7.66). The two last-mentioned products are probably formed via the radical 7.63. Direct evidence for this radical was found by experiments conducted in the presence of the radical scavenger 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO) to give 7.65 in good yield. In other experiments, dimerization and oxidation products of the radical 7.63 were identified. 

The hyperfine coupling constant of the EPR spectrum of 4-amino-2,2,6,6-tetramethylpiperidine-l-oxyl, a commercially available stable free radical, has been... 

A QD-based sensor for carbon-centered radicals (alkyl or phenyl radicals) was developed by the use of 4-amino-2,2,6,6-tetramethylpiperidine oxide (4-amino-TEM-PO)-functionalized CdSe QDs. The presence of a nitroxide moiety in the functional capping layer leads to quenching of the luminescence of the QDs. The nitroxide units of the capping layer read with the carbon-centered radical to yield the diamagnetic alkoxyamine-modified protecting layer. As the resultant units are unable to quench the luminescence of the QDs, this leads to an intensified luminescence upon interadion with readive carbon-centered radicals. 

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