Products of ozonolysis

When the objective is analytical the products of ozonolysis are isolated and identi lied thereby allowing the structure of the alkene to be deduced In one such example an alkene having the molecular formula C Hig was obtained from a chemical reaction and was then subjected to ozonolysis giving acetone and 2 2 dimethylpropanal as the products... 

During work-up of the products of ozonolysis of R- and S-citronellic acids, a substantial quantity of the highly explosive trimeric acetone peroxide (3,3,6,6,9,9-hexamethyl-l,2,4,5,7,8-hexoxonane) was unwittingly isolated by distillation at 105-135°C to give the solid m.p. 95°C. The peroxide appears to have been produced by ozonolysis of the isopropylidene group in citronellic acid, and presumably the same could occur when any isopropylidene group is ozonised. Appropriate care is advised. 

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],... 

The product of ozonolysis of 1,1-difluoroethylene is a shock-sensitive peroxidic species [1], which reacts vigorously with aqueous potassium iodide [2],... 

Chan, W.F. and Larson, R.A. Mechanistrrs and products of ozonolysis of aniline in aqueous solution containing nitrite ion. Water Res., 25(12) 1549-1544, 1991a. 

On an exam you may be asked to determine the structural formula of the starting alkene given the ozonolysis products. A useful technique is to work backward from the products of ozonolysis. By cutting off the oxygens and then combining the two pieces, you get the starting alkene. 

Benzo ring cleavage of acridine results from oxidation with permanganate, the product being quinoline-2,3-dicarboxylic acid (acridinic acid), which is also the main product of ozonolysis in methanol (Scheme 26) (64JA38). 

A violent explosion was experienced at 50° C when attempting to distil the products of ozonolysis in dichlormethane. At this temperature the solvent would have evaporated, leaving ozonide. 

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 two carbons that were doubly bonded to each other in the alkene become the carbons that are doubly bonded to oxygen in the products of ozonolysis. Therefore, mentally remove the oxygens and connect these two carbons by a double bond to reveal the structure of the starting alkene. 

It will be cleaved by ozone at each double bond. The product of ozonolysis is, therefore,... 

By contrast, the homolog 192 with a trisubstituted double bond forms a different 1,2-dioxane 194 based on the product of ozonolysis of the isopropylidene group (Scheme 65) <2000H(53)1293>. 

The product of ozonolysis was acetylated in 6 ml of pyridine and 3 ml acetic anhydride at room temperature for 17 hours, 6 ml xylene was added and the reaction mixture evaporated in vacuo. The residue was triturated with ether-hexane affording crystalline (+/-)-2a-(2-acetoxy-2-carboxyvinyl)-3p-hydroxy-5-oxo-ip-cyclopentaneheptanoic acid methyl ester 6-lactone, 5-cyclic ethylene acetal, m.p. 82-84°C. 

The terpene terpinolene, C10Hi6, gives compound A, C10H2o, on reaction with H2/Pt. A shows seven peaks in its 13C-NMR spectrum. The products of ozonolysis of terpinolene are shown in the following equation. Show the structure of terpinolene. 

One of the most common uses of ozonolysis has been for determining the positions of double bonds in alkenes. For example, if we were uncertain of the position of the methyl group in a methylcyclopentene, the products of ozonolysis-reduction would confirm the structure of the original alkene. 

The presence of both aldehyde and carboxylic acid products of ozonolysis indicates that both double and triple bonds are present in erythrogenic acid. 

Stearolic acid contains a triple bond because the products of ozonolysis are carboxylic acids. 

Ozonides are hardly ever isolated. Rather, conversions to products of ozonolysis are carried out in the same reaction vessels see Oxidative Cleavage of Double Bonds, page 77). 

When ozone is passed through a solution of dihydrocodeine in formic acid, a-ozodihydrocodeine [m, R = Me] is formed. This, on hydrolysis, affords dihydromorphinic acid [Lin], which is also obtained by the hydrolysis of a-ozodihydroethylmorphine [mi, R = Et], the product of ozonolysis of dihydroethylmorphine, showing that ozonolysis involves cleavage of the aromatic nucleus between carbon atoms 3 and 4 [371],... 

Halsall and his colleagues have elucidated the structures of a number of the minor products of ozonolysis of methyl acetylbetulinate (162). In addition to the expected nor-ketone they obtained the two trisnor-compounds (163) and (164), the Baeyer-Villiger product (165), and the bisnor-acid (166). These results are rationalised in terms of three different decomposition mechanisms for the ozonide... 

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