Urea hydroperoxide

SYNS CARBAMIDE PEROXIDE GLY-OXIDE HYDROGEN PEROXIDE CARBAMIDE HYDROPERIT HYPEROL ORTIZON PERCARBAMIDE PERHYDRIT PERHYDROL-UREA THENARDOL UREA DIOXIDE UREA HYDROGEN PEROXIDE pOT) UREA HYDROGEN PEROXIDE SALT UREA HYDROPEROXIDE UREA PEROXIDE pOT)... 

MTO [methyltrioxorhenium(VII), cf. Chapter 3.3.13] can be used as a catalyst for the epoxidation of olefins with urea hydroperoxide in [EMIMJBF4 [19]. The activity is reported to be comparable with the reaction in organic solvents but side reactions are suppressed. The use of an ionic liquid as a co-solvent in CH2CI2 for the enantioselective Mn-salen complex-catalyzed epoxidation of olefins with Na(OCl) was reported to result in enhanced reaction rates at no loss of enantioselectivity [20]. Cr-salen complexes can further be used for the asymmetric kinetic resolution of epoxides by ring-opening with azide [21]. 

The material 6 showed a remarkable catalytic activity in the oxidation of thioethers 13 to sulfoxides 14 by urea hydroperoxide (UHP) or H O (Scheme 2). Although the conversion and selectivity (for 14 over 15, >90%) was reasonable with UHP for the substrates with smaller substituents, 13a and 13b, the ones with bulkier substrates 13c and 13d failed to produce any measurable conversion. The conversion increases to 100% by changing UHP with H O. The catalytic activity of 6 for selective sulfoxidation remains similar even after 30 cycles. Despite the fact that no asymmetric induction was found in the catalytic sulfoxidations, enantioen-riched sulfoxides were obtained by enantioselective sorption of the resulting racemic mixture by the chiral pores of 6, which occured simultaneously with the catalytic process. Thus, after catalytic oxidation of 13a, (5)-14a was preferentially absorbed by the pore of 6 leaving exactly equal amount of the excess ) -enantiomer in the solution phase (-20% ee). The combination of high catalytic activity and enantioselective sorption property of 6 provides a unique opportunity to device a one-step process to produce enantioenriched products. 

Several other MOFs have also been used as oxidation catalysts. Kim and coworkers used [Zn2(BDC)(L-Lac)(DMF)] (DMF) as a heterogeneous catalyst for the oxidation of thioethers to sulfoxides by urea hydroperoxide (UHP) or hydrogen peroxide (H2O2) [26]. Its size selectivity was illustrated by the higher conversion of smaller sulfides over larger ones. Snejko and coworkers reported the use of ln2(OH)3(BDC)i,5 [27] and [Sc2(BDC)3] [28] as active catalysts for the oxidation of alkylphenylsulfides. 

Urea hydrogen peroxide Urea hydroperoxide. See Urea peroxide Urea, hydroxy-. See Hydroxyurea Urea/melamine/formaldehyde resin CAS 25036-13-9... 

Synonyms Carbamide peroxide Hydrogen peroxide carbamide Hydrogen peroxide with urea (1 1) Percarbamide Perhydrol-urea Urea dioxide Urea hydrogen peroxide Urea hydroperoxide Empirical CH6N2O3 Formula H2NCONH2 H2O2 Properties Wh. cryst. orcryst. powd. sol. in water. 

Heterogeneous catalytic oxidation of sulfides in ionic liquids by anhydrous H2O2 or urea hydroperoxide with MCM-41 and related mesoporous catalysts containing Ti or Ti and Ge was studied by Hardacre and coworkers [51]. The Ti-based catalyst gave a quite selective sulfoxidation. Addition of Ge to Ti increased the rate of the oxidation but reduced the selectivity toward sulfoxide [51a]. 

NUrene Formation. The dibenzothiophene moiety may be converted to a nitrene precursor in two steps. The title compound is first oxidized to the sulfoxide in the presence of urea hydroperoxide (UHP). Addition of trifluoroacetic anhydride and an amine allows the formation of the corresponding sulfinimine, which generates a nitrene species under photochemical conditions (eq 9). ... 

This test is used for both in vitro and in vivo determinations. It involves reacting thiobarbituric acid (TBA) with malondialdehyde (MDA), produced by lipid hydroperoxide decomposition, to form a red chromophore with peak absorbance at 532 nm (Fig. 10.1). The TBARS reaction is not specific. Many other substances, including other alkanals, proteins, sucrose, or urea, may react with TBA to form colored species that can interfere with this assay. 

Another important asymmetric epoxidation of a conjugated systems is the reaction of alkenes with polyleucine, DBU and urea H2O2, giving an epoxy-carbonyl compound with good enantioselectivity. The hydroperoxide anion epoxidation of conjugated carbonyl compounds with a polyamino acid, such as poly-L-alanine or poly-L-leucine is known as the Julia—Colonna epoxidation Epoxidation of conjugated ketones to give nonracemic epoxy-ketones was done with aq. NaOCl and a Cinchona alkaloid derivative as catalyst. A triphasic phase-transfer catalysis protocol has also been developed. p-Peptides have been used as catalysts in this reaction. ... 

Synonyms Albone Carbamide peroxide Hydrogen dioxide Hydroperite Hydroperoxide Inhibine Per-hydrol Peroxan Urea hydrogen peroxide Urea peroxide... 

Linstead and Whalley showed that urea complexes can be used for effective separation of straight- and branched-chain carboxylic esters. Swem s group used the method to advantage in working up autoxidized methyl oleate for isolation of long-chain hydroperoxides. These peroxides behave like branched-chain compounds because of the bulky peroxide group and remain in solution when nonperoxidic components of the mixture are precipitated as urea complexes. 

MERCURIC THIOCYANATE (592-85-8) Hg(SCN)i Moderately unstable solid. Possible violent reaction with strong oxidizers strong acids organic peroxides, peroxides and hydroperoxides potassium chlorate potassium iodate, silver nitrate, sodium chlorate, nitric acid. Incompatible with ammonia, chlorates, hydrozoic acid, methyl isocyanoacetate, nitrates, nitrites, perchlorates, sodium peroxyborate, trinitrobenzoic acid, urea nitrate. When heated, this material swells to many times its original bulk. Attacks aluminum in the presence of moisture. Decomposes above 329°F/165°C, releasing toxic mercury and cyanide fumes, and sulfur and nitrogen oxides. On small fires, use dry chemical powder (such as Purple-K-Powder), alcohol-resistant foam, or COj extinguishers. MERCURIC (Spanish) (7439-97-6) see mercury. 

LEAD (7439-92-1) Dust or powders form flammable or explosive mixture with air. Powder reacts violently with ammonium nitrate, sodium acetylide, strong oxidizers. Reacts with and/or forms heat- and shock-sensitive explosive products with ammonia, chlorine trifluoride, A/A -dinitro-l,2-diaminoethane, disodium acetylide, hydrogen peroxide (concentrated), hy-drazoic acids, isopropylbenzene hydroperoxide, methyl isocyanoacetate, nitryl fluoride, oxidizers, picric acid, sodium acetylide, sodium peroxyborate, sodium azide, trinitrobenzoic acid, urea nitrate. 

---