Tertiary-butylhydroperoxide

Tertiary butylhydroperoxide (TBHP) is a popular oxidizing agent used with certain catalysts. Because of its size, TBHP is most effective with catalysts containing large pores however, it can also be used with small-pore catalysts. Using first-row transition metals, Cr and V, impregnated into pillared clays, TBHP converts alcohols to ketones, epoxidizes alkenes, and oxidizes allylic and benzylic positions to ketones.83-87... 

In their reactions with tertiary butylhydroperoxide, H and eaq show a different selectivity (Phulkar et al. 1990). While H undergoes reactions (12) and (13) with about equal probability, i.e both fBuO and OH are formed, eaq yields only fBu() [reaction (14)]. This preference in splitting the peroxidic bond is due to the much higher solvation energy of the hydroxide compared to the tertiary butoxide ion. For a detailed study on the reaction of H with H202 see Mezyk and Bartels (1995). 

Abbreviations AD, asymmetric dihydroxylation BPY, 2,2 -bipyridine DMTACN, 1,4-dimethyl-l,4,7-triazacyclonane EBHP, ethylbenzene hydroperoxide ee, enantiomeric excess HAP, hydroxyapatite LDH, layered double hydroxide or hydrotalcite-type structure mCPBA, meta-chloroperbenzoic acid MTO, methyltrioxorhenium NMO, A-methylmorpholine-A-oxide OMS, octahedral molecular sieve Pc, phthalocyanine phen, 1,10-phenantroline PILC, pillared clay PBI, polybenzimidazole PI, polyimide Por, porphyrin PPNO, 4-phenylpyridine-A-oxide PS, polystyrene PVP, polyvinylpyridine SLPC, supported liquid-phase catalysis f-BuOOH, tertiary butylhydroperoxide TEMPO, 2,2,6,6-tetramethyl-l-piperdinyloxy TEOS, tetraethoxysilane TS-1, titanium silicalite 1 XPS, X-ray photoelectron spectroscopy. 

Biel B, Younes M, Brasch H. Cardiotoxic effects of nitrofurantoin and tertiary butylhydroperoxide in vitro are oxygen radicals involved Pharmacol Toxicol 1993 72(l) 50-5. 

Figure 6. Synthesis of adipic acid over ship-in-the-bottle catalysts (t.-BHP tertiary-butylhydroperoxide).

Over iron-phthalocyanine encaged in zeolite Y and using tertiary-butylhydroperoxide (t.-BHP) as oxidant, even cyclohexane can be converted to adipic acid. Selectivities of up to 35 % at conversions around 85 % have been reported. Unfortunately, however, a reaction time of 33 hours at 60 °C was required to achieve this conversion. Although the activity of the latter catalyst is certainly much too low to compete with the conventional catalytic systems for adipic acid synthesis, it provides interesting prospects for further developments. For the near future, we perceive that more and more groups will be working in this interesting field of catalysis by zeolite inclusion compounds. 

Parton et al. [126] reported on the development of a synthetic system that mimics the cytochrome P-450 enzyme. They embedded zeolite Y crystallites containing encapsulated iron phthalocyanine complexes in a polymer membrane. Using tertiary-butylhydroperoxide as oxidant, this catalytic system oxidizes alkanes at room temperature with rates comparable to those of the real enzyme. 

Figure 9. Proposed link between pyridine nucleotide-related release from rat liver mitochondria and ADP-ribosylation in the inner mitochondrial membrane. Oxidation of mitochondrial pyridine nucleotides can be brought about by various compounds tertiary butylhydroperoxide (BuOOH) is shown (1) glutathione peroxidase (2) glutathione reductase (3) energy-linked pyridine nucleotide transhydro-genase (4) NAD glycohydrolase (5) Ca /H antiporter, modified by ADP-ribose. NAm, nicotinamide. (From Richter et al., 1985).

Turnover numbers (T.O.N.) after 24 h, epoxide yield (mmol) and product distribution (%) for the 1-octene epoxidation with Ti-MCM-41 using tertiary butylhydroperoxide as oxidant. 

The lodoxybenzene is apparently blocking the zeolite pores (1,28), and consequently only overall turnovers of the order of 10 are observed (1,26,28-30). The use of tertiary butylhydroperoxide as oxidant and the ferrocene route for the synthesis of FePcY, results in an increase of the turnovers by more than 2 orders of magnitude (23,48,49) (Table 2). 

It was shown somewhat later that epoigr compoimds inhibit the radical decomposition of hydroperoxides [12, 247]. In an investigation of the decomposition of tertiary butylhydroperoxide imder the action of cobalt octoate, it was established that the combination of the epoxy resin "Epone 834 with a cadmium salt is a better inhibitor of peroxide decomposition than each of the components individually this mixture is close to dibutyltin dilaurate in effectiveness. 

Inclusion in the reaction of a cooxidant serves to return the osmium to the osmium tetroxide level of oxidation and allows for the use of osmium in catalytic amounts. Various cooxidants have been used for this purpose historically, the application of sodium or potassium chlorate in this regard was first reported by Hofmann [7]. Milas and co-workers [8,9] introduced the use of hydrogen peroxide in f-butyl alcohol as an alternative to the metal chlorates. Although catalytic cis dihydroxylation by using perchlorates or hydrogen peroxide usually gives good yields of diols, it is difficult to avoid overoxidation, which with some types of olefins becomes a serious limitation to the method. Superior cooxidants that minimize overoxidation are alkaline t-butylhydroperoxide, introduced by Sharpless and Akashi [10], and tertiary amine oxides such as A - rn e t h y I rn o r p h o I i n e - A - o x i d e (NMO), introduced by VanRheenen, Kelly, and Cha (the Upjohn process) [11], A new, important addition to this list of cooxidants is potassium ferricyanide, introduced by Minato, Yamamoto, and Tsuji in 1990 [12]. 

The photostabilizing efficiency of A-methyl HAS pNCH3, e.g. 28,29,31, R = CH3,32) is within experimental error comparable to that of secondary HAS I NH [43,111,173,174], The simplest and most logical explanation includes a transformation of NCH3 into NH. Some studies contributed to the mechanism of this conversion. Model A-substituted tetramethylpiperidines having an H-atom on the a-carbon in the A-substituent were found to be photo-oxidized more easily than the corresponding secondary HAS [173]. Besides, the tertiary HAS decomposed /ert-butylhydroperoxide more rapidly than did NH. The reaction rates with terf-butylhydroperoxide at 132 °C were as follows ... 

The most important class of solid-state enzyme mimics is based on zeolites. Zeolites are solid materials composed of Si04 or AIO4 tetrahedra linked at their corners, affording a three-dimensional network with small pores of molecular dimensions. They possess a unique feature of a strictly uniform pore diameter. In particular, zeolites with encapsulated metal complexes are used as inimics of cytochrome P-450.An efficient enzyme mimic was obtained by encapsulating an iron phthalocyanine complex into crystals of zeolite Y, which were, in turn, embedded into a polydimethylsiloxane membrane acting as a mimic of the phospholipid membrane.With t-butylhydroperoxide as the oxidant, the system hydroxyl-ates alkanes at room temperature with rates comparable to those for the enzyme. It shows similar selectivity (preference oxidation of tertiary C-H bonds) and a large kinetic isotope effect of nine. 

In an unusual oxidative amidation of tertiary amines (typically Ar-NMc2) with aldehydes, R-CHO, amides are formed with the loss of an alkyl group. .. methyl in this case. The amide product, Ar-N(Me)CO-R, is formed in good yield using iron(II) catalysis in refluxing acetonitrile, and i-butylhydroperoxide as oxidant. 

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