F-butoxyl

Mihaljevic B, Medved-Rogina B, Razem D (1999) Rate constant for the reaction of the f-butoxyl radical with Fe(ll) ion. Radiat Phys Chem 55 593-597... 

Reactions of trioxolanes and trithiolanes with radical species have received little attention. The action of hydroxyl radicals on 1,3,2-dioxathiolane 2-oxide (16) gave rise to the radicals (150), (151) and (152), which were detected by ESR spectroscopy after trapping with the nitromethane aci anion (76JCS(P2)1040). The f-butoxyl radical likewise attacked (16) at sulfur to yield radical (153) (77JMR(27)509). 

After extended photolysis in benzene through a Pyrex filter, rert-butyl alcohol and acetone were both observed in modest yield. They were postulated to derive from secondary chemistry of the unobserved sulfenic ester 79, which produces the f-butoxyl radical 81. Traces of phenyl disulfide 46 were also found, along with a significant amount of the sulfide 80, derived from deoxygenation. 

Section 8.1.4 on the competition of radical-molecule reactions with unimolecular processes refers almost exclusively to competitions between hydrogen abstraction or double bond addition with the fl-cleavage of the radical, which is used as a clock . In the case of f-butoxyl radicals, these studies involve the measurement of t-butanol-to-acetone ratios. So in the case of subsection 8.I.3.1, these studies do not provide information on the site of attack, which needs to be derived from infrared or other experiments. The ratios of reactivity reported in this... 

Alkoxyl radicals react with a variety of antioxidants and biological compounds, such as f-butoxyl radical reaction with a range of fatty acids, generating t-butanol and a fatty acid radical via hydrogen abstraction [135]. Introducing unsaturated bonds into the fatty acids was seen to increase the abstraction rate constant. These radicals have also been seen to react with the antioxidants quercetin, crocin and crocetin, ascorbate and Trolox, as well as with the DNA bases, thymidine and adenosine [ 131 ]. In the case of quercetin its phenoxyl radical was observed, and this would be expected to occur for Trolox as weU, though the authors used competition kinetics to monitor this reaction rather than direct monitoring of the product. 

A number of reports on the thermal decomposition of peroxides have been published. The thermal decompositions of f-butyl peroxyacetate and f-butyl peroxypivalate, of HCOH and a kinetic study of the acid-induced decomposition of di-f-butyl peroxide in n-heptane at high temperatures and pressures have been reported. Thermolysis of substituted f-butyl (2-phenylprop-2-yl) peroxides gave acetophenone as the major product, formed via fragmentation of intermediate alkoxy radicals RCH2C(Ph)(Me)0. A study of the thermolysis mechanism of di-f-butyl and di-f-amyl peroxide by ESR and spin-trapping techniques has been reported. The di-f-amyloxy radical has been trapped for the first time. jS-Scission reaction is much faster in di-f-amyloxyl radicals than in r-butoxyl radicals. The radicals derived from di-f-butyl peroxide are more reactive towards hydrogen abstraction from toluene than those derived from di-f-amyl peroxide. 

There are numerous reactions of interest that fit the description mentioned above. For example, the reaction of tert-butoxyl with aliphatic alcohols is essentially invisible or silent in nLFP. A practical example would be the reaciton of f-BuO" with 2-propanol, in which the reaction with benzhydrol (diphenyl methanol) could be used as a probe. The mechanism is shown in Scheme 18.3 for this example. 

Fig. 28. Gel chromatograms of poly(diethylene glycol adipate) with terminal butoxyl groups, M = 700, f = 0, diethylene glycol and a ring consisting of adipic acid and diethylene glycol, M = 316 styragel columns 60, I03, 10 A, eluent tetrahydrofuran, u = 1 ml/min, volume of the sample 2 ml, refractometer, t = 24 °C...

BUTOXYL (4435-53-4) Combustible liquid (flash point 170°F/77°C). Incompatible with strong acids, nitrates, oxidizers. 

Choi, S.-Y., RE. Eaton, P.F. Hollenberg, K.E. Liiu, S.J. Lippard, M. Newcomb et at. (1996). Regiochemical variations in reactions of methyl-cubane with tert-butoxyl radical, cytochrome P-450 enzymes and a methane monooxygenase system. J. Am. Chem. Soc. 118, 6547-6555. 

A mixture of piperidine and abs. ethanol added with stirring at —5° to n-butyraldehyde and ferf-butyl acetoacetate, stirring continued 5 hrs., then kept 44 hrs. at ca. —15°, and the crude intermediate heated at 130-140° in the presence of p-toluenesulfonic acid until a constant pressure indicates completion of the decomposition 3-hepten-2-one. Y 93%. F. e. s. S.-O. Lawesson et al., Acta Ghem. Scand. 17, 2216 (1963) C-decarbo-ferf-butoxylation with simultaneous dehydration, 2-cyclohexenones, s. R. 83, 464 (1964) reactions with ferf-butyl cyanoacetate s. Arkiv Kemi 23, 453 (1965). 

Protective N-carbobromo-fert-butoxyl groups can be removed selectively by heating in methanol or ethanol, a unique deprotection technique. - E Startg. protected peptide refluxed 1 hr. in ethanol -> product. Y 89%. F. e. and cleavage methods s. T. Ohnishi, H. Sugano, and M. Miyoshi, Bull. Chem. Soc. Japan 45, 2603 (1972). 

A soln. of p-methoxybenzyloxycarbonylazide in dioxane added at room temp, with stirring to glycine in water placed in the vessel of a pH-stat, the pH adjusted by addition of NaOH until the reaction proceeds at a practical rate, at pH 10.7, and the product isolated after 3 hrs. when NaOH-uptake has ceased N-p-methoxybenzyloxycarbonylglycine. Y 92%. F. e. s. F. Vandesande, Bull. Soc. diim. Belg. 79, 397 (1970) s. a. J.J. Ferraro, Biodiem. Prep. 13, 39 (1971) with triethylamine s. N. F. Estrin, A. A. Alemany, and D. F. De Tar, Biochem. Prep. 13, 18 (1971) with tetramethylguanidine, N-carbo-rerr-butoxylation, s. A. Ali, F. Fahrenholtz, and B. Weinstein, Ang. Ch. 84, 259 (1972). 

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