Hydroperoxides ozonolysis

Most ozonolysis reaction products are postulated to form by the reaction of the 1,3-zwitterion with the extmded carbonyl compound in a 1,3-dipolar cycloaddition reaction to produce stable 1,2,4-trioxanes (ozonides) (17) as shown with itself (dimerization) to form cycHc diperoxides (4) or with protic solvents, such as alcohols, carboxyUc acids, etc, to form a-substituted alkyl hydroperoxides. The latter can form other peroxidic products, depending on reactants, reaction conditions, and solvent. 

The crude products of ozonolysis at — 30°C of the chloroalkene tended to decompose explosively on warming to ambient temperature, particularly in absence of solvents. The products included the individually explosive compounds acetyl 1,1,-dichloroethyl peroxide, 3,6-dichloro-3,6-dimethyl-2,3,5,6-tetraoxane and diacetyl peroxide [1], Ozonolysis in ethyl formate saturated with hydrogen chloride gives a high yield of 1,1-dichloroethyl hydroperoxide as a further unstable intermediate product [2],... 

When ozonolysis is done in alcoholic solvents, the carbonyl oxide fragmentation product can be trapped as an a-hydroperoxy ether.146 Recombination to the ozonide is then prevented, and the carbonyl compound formed in the fragmentation step can also be isolated. If the reaction mixture is treated with dimethyl sulfide, the hydroperoxide is reduced and the second carbonyl compound is also formed in good yield.147 This procedure prevents oxidation of the aldehyde by the peroxidic compounds present at the conclusion of ozonolysis. 

Ozonolysis of alkenes in participating solvents such as alcohols often leads to trapping of intermediates. Most commonly, an alcohol will react with the carbonyl oxide zwitterion, generated from cycloreversion of the primary ozonide (Section 4.16.8.2), to give an alkoxy hydroperoxide. The secondary ozonide (1,2,4-trioxolane) is usually more stable to nucleophilic attack from alcohols. 

SCHEME 13. Synthesis of a-alkoxy hydroxy hydroperoxides by ozonolysis, OMe OOH... 

SCHEME 20. Application of oxidative ozonolysis for structural analysis of unsaturated fatty acid hydroperoxides... 

Carbenes, dioxirane preparation, 1132 Carbocations, antimalarial endoperoxides, 1309 Carbohydrate hydroperoxides, Mo-catalyzed olefin epoxidation, 432, 436 Carbohydrates, TBARS assay, 669 Carbonate esters, oxidative ozonolysis, 737, 738... 

NMR spectroscopy, 694-5 vibrational spectra, 692 X-ray diffraction, 695-6 synthesis, 309-51 tertiary, 690-1 theoretical aspects, 67-84 thymine ozonolysis, 616 see also Chiral hydroperoxides DNA... 

SIDS database, cumyl hydroperoxide, 622 Silane hydrotrioxides, ozonolysis intermediates, 811 Silanes... 

Trimethylsilyl hydroperoxide preparation bis(trimethylsilyl) peroxide hydrolysis, 801 tetraethylsilane ozonolysis, 810 trimethyl chlorosilane reaction, 776, 777... 

Finally, a series of novel hydroperoxy-l,2-dioxanes 233a, b (Scheme 65) were synthesized by hydroperoxide rearrangement and ozonolysis <2006EJ02174> all the products showed weak antimalarial acitivity. Also the epoxy-endoperoxides 234a,b were designed which proved to have inhibitory acitivity against Candida albicans (Scheme 65) <2007BMC36>. 

Antimalarial activity is also shown by 13,43-tetraoxanes and these compounds have been synthesised by the acid-catalysed dimerisation of ozonides <99JMC2604>. Ozonolysis of vinyl ethers and cyclocondensation of the derived bis(hydroperoxides) with carbonyl... 

Gab, S E. Hellpointner, W. V. Turner, and F. Korte, Hydroxymethyl hydroperoxide and Bis(hydroxymethyl)-peroxide from Gas Phase Ozonolysis of Naturally Occurring Alkenes, Nature, 316, 535-536 (1985). 

Neeb, P., F. Sauer, O. Horie, and G. K. Moortgat, Formation of Hydroxymethyl Hydroperoxide and Formic Acid in Alkene Ozonolysis in the Presence of Water Vapour, Atmos. Environ., 31, 1417-1423 (1997). 

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