Amine-terminated oxide

An amine-terminated poly ether (ATPE) is prepared as follows. Charge poly(tetramethylene oxide) diol (PolyTHF 1000, BASF, 75.96 g, 0.0759 m) to a 500-mL three-neck round-bottom flask fitted with a thermocouple, a mechanical stirrer, and a vacuum port. Add tert-butylacetoacetate (24.04 g, 0.1582 m) and apply vacuum. Heat at 175° C for 4 h, Fourier transform infrared (FTIR) analysis should indicate complete loss of the polyol OH absorption at 3300 cm. The room temperature viscosity of the product should be about 520 mPa-s. React this acetoacetylated product (85.5 g, 0.0649 m) with cyclohexylamine (14.5 g, 0.1465 m) at 110° C under vacuum for several hours. Cool the resultant cyclohexylaminocrotonate poly ether product to room temperature (1790 mPa-s at room temperature). 

Blattmann has also suggested an alternative pathway which involves a terminal oxidation of the chain after 3-hydroxylation and has presented data for the metabolism of 2-hydroxybutylbutylnitros-amine indicating that this does occur. ... 

Aromatic amines terminate chains in oxidizing hydrocarbons with the stoichiometric coefficient between 1 and 2 as a result of the consecutive reactions (see Chapter 15). 

Intramolecular rhodium-catalyzed carbamate C-H insertion has broad utility for substrates fashioned from most 1° and 3° alcohols. As is typically observed, 3° and benzylic C-H bonds are favored over other C-H centers for amination of this type. Stereospecific oxidation of optically pure 3° units greatly facilitates the preparation of enantiomeric tetrasubstituted carbinolamines, and should find future applications in synthesis vide infra). Importantly, use of PhI(OAc)2 as a terminal oxidant for this process has enabled reactions with a class of starting materials (that is, 1° carbamates) for which iminoiodi-nane synthesis has not proven possible. Thus, by obviating the need for such reagents, substrate scope for this process and related aziridination reactions is significantly expanded vide infra). Looking forward, the versatility of this method for C-N bond formation will be advanced further with the advent of chiral catalysts for diastero- and enantio-controlled C-H insertion. In addition, new catalysts may increase the range of 2° alkanol-based carbamates that perform as viable substrates for this process. 

Teeth whiteners, percarbamide, 623 Temperature, reaction rates, 903-12 Terminal olefins, selenide-catalyzed epoxidation, 384-5 a-Terpinene, peroxide synthesis, 706 a-Terpineol, preparation, 790 Terrorists, dialkyl peroxide explosives, 708 Tertiary amines, dioxirane oxidation, 1152 Tertiary hydroperoxides, structural characterization, 690-1... 

Terminal alkenes could be efficiently aminated by nonhindered secondary amines in a process requiring 1 equiv. of palladium(II) chloride, 3 equiv. of amine and a reduction at temperatures below -20 C (path a, Scheme 5) 21,22 however, primary amines and/or internal alkenes were less efficient, producing only 40-50% yields of amination product. Oxidative cleavage of the unstable o-alkylpalladium(II) in the presence of a nucleophile resulted in vicinal oxamination or diamination of the alkene (path b).23,24 Car-bonylation resulted in the isolation of stable o-acylpalladium(II) species (path c),23 which were oxidatively cleaved to give 3-amino esters (path d)26 or further carbonylated to give y-amino-a-ketoamidei (path e).27... 

Allyl amines can also be formed in an oxidative environment. Nicholas et al. have shown that instead of phenyl hydroxylamine as the nitrogen donor, it is possible using f-BuOOH as the terminal oxidant and the molybdenum catalyst described above [65]. The procedure is analogues to the in situ hetero-Diels-Alder reaction of nitroso compounds developed earlier by others [66]. 

The relationships of oxidation potential to radical reactivity index Sr and nucleophilic reactivity index Sn illustrated in Figure 4 are very similar to those with antioxidation and antiozonization, where the maximum values were observed at 0.4 and 0.25 volt. Therefore, antioxidation seems to proceed by a radical mechanism in contrast to the nucleophilic type of antiozonization. Indeed, the antioxidation effect of amines toward NR, SBR, BR, and HR is well correlated with radical reactivity as shown in Figures 5-8. The protection of SBR solution by amines from oxidative degradation and the termination of chain reaction in the oxygen-Tetralin system are also shown as functions of Sr in Figures 9 and 10. 

In practice in the literature of the past 20 years the important results with ruthenium in epoxidation are those where ruthenium was demonstrated to afford epoxides with molecular oxygen as the terminal oxidant. Some examples are presented (see later). Also ruthenium complexes, because of their rich chemistry, are promising candidates for the asymmetric epoxidation of alkenes. The state of the art in the epoxidation of nonfunctionalized alkenes is namely still governed by the Jacobsen-Katsuki Mn-based system, which requires oxidants such as NaOCl and PhIO [43,44]. Most examples in ruthenium-catalysed asymmetric epoxidation known until now still require the use of expensive oxidants, such as bulky amine oxides (see later). 

Figure 6.40. Schematic of the growth of tin oxide nanoclusters at room temperature. The TEM images on the right illustrate interdendritic stabilized nanoclusters using (a) PAMAM and (b) amine-terminated poly(ethyleneimine) hyperbranched polymer hosts. Reproduced with permission from Juttukonda, V. Paddock, R. L. Raymond, J. E. Denomme, D. Richardson, A. E. Slusher, L. E. Fahlman, B. D. J. Am. Chem. Soc. 2006,128, 420. Copyright 2006 American Chemical Society.

By using a multistep procedure, DNA molecules have been covalently attached to SWNTs. First, the purified SWNTs were oxidized to form carboxylic acid groups at the ends and sidewalls, followed by reaction with thionyl chloride and ethylenediamine to produce amine-terminated sites. The amines were then reacted with the heterobifunctional cross-linker succinimi-dyl 4-(iV-maleimidomethyl)cyclohexane-l-carboxylate (SMCC), leaving the surface terminated with maleimide groups. Finally, thiol-terminated DNA reacted with these groups to produce DNA-modified SWNTs [161]. AAHien DNA is covalently attached to SWNTs, a better stability, accessibility and selectivity are expected during competitive hybridization. 

Despite the drawbacks of this method, it has been used to prepare a tremendous number of polypeptide hybrid block copolymers (Table 1), and when carefully executed provides reasonably well-defined samples. Synthetic polymer domains have been prepared by addition polymerization of conventional vinyl monomers, such as styrene and butadiene, as well as by ringopening polymerization in the cases of ethylene oxide and e-caprolactone. The generality of this approach allows NCA polymerization off of virtually any primary amine functionality, which was exploited in the preparation of star block copolymers by polymerization of sarcosine NCA from an amine-terminated trimethyleneimine dendritic core [37]. In most examples, the polypeptide domain was based on derivatives of either lysine or glutamate, since these form a-helical polypeptides with good solubility characteristics. These residues are also desirable since, when deprotected, they give polypep-... 

Even though dendrimer surfaces can be constructed to exhibit all possible functionalities, amine-terminating groups are synthetically more appealing and have been used most extensively. The potentially useful thiolated dendrimers self-oxidize, while carboxylated dendrimers tend to form intramolecular anhydrides once activated. This last situation may cause defects upon carbohydrate attachment. Although alcohols seem also attractive, a priori, their direct use in glycosylation chemistry is hampered by potentially difficult complete anomeric stereocontrol. 

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