Decalins oxidation

K [29]. The experimentally measured values were the following the induction period t of decalin oxidation, induction period t2 of PP film oxidation in an atmosphere of dioxygen, induction period t3 of PP film oxidation in the dioxygen flow, and time of evaporation of a half of phenol t1/2 in a nitrogen atmosphere at T 403 K. The results are given below. 

Saturated hydrocarbons have lower electron affinity than unsaturated hydrocarbons. In dry argon, the decalin anion radicals are formed, if at all, in extremely low concentration. It suggests that their further reactions are insignificant. In the presence of decalin, no wear occurs. In dry or wet air, decalin works worse, but still effectively. The anion radicals of oxygen, which are formed in greater concentration than that of the anion radicals of decalin, can initiate decalin oxidation. Oxidation products were capable of accepting exoelectrons and were involved in further reactions, with the formation of polymeric or organometallic lubricants. 

Decalins oxidized by p-nitroperoxybenzoic acid in refluxing chloro-... 

Diehl et al showed that naphthalene oxidized over Pt/Al203 at 240" C far over the light-off temperature of -decane (171°C). However, when the bicyclic molecule is partially (tetraline) or totally (decaline) hydrogenated, its oxidation becomes much easier (T50 = 230" C for tetraline and 205°C for decaline). Oxidation of polycyclic hydrocarbons is often not total at moderate temperatures. Two kinds of behavior can be observed ... 

CoF is used for the replacement of hydrogen with fluorine in halocarbons (5) for fluorination of xylylalkanes, used in vapor-phase soldering fluxes (6) formation of dibutyl decalins (7) fluorination of alkynes (8) synthesis of unsaturated or partially fluorinated compounds (9—11) and conversion of aromatic compounds to perfluorocycHc compounds (see Fluorine compounds, organic). CoF rarely causes polymerization of hydrocarbons. CoF is also used for the conversion of metal oxides to higher valency metal fluorides, eg, in the assay of uranium ore (12). It is also used in the manufacture of nitrogen fluoride, NF, from ammonia (13). 

Treatment of Decalin with acetyl chloride and aluminum chloride in ethylene chloride as solvent gives a complex mixture of products as shown (15). By variation of the reaction parameters, however, it is possible to maximize the yield of the remarkable reaction product, 10 j3-vinyl-/m j-Decalin l/8,r oxide (5). This vinyl ether undoubtedly... 

Appropriate choice of catalyst permitted formation of either of two dihydro derivatives of mevinolin in high yield (67). Hydrogenation of mevinolin over platinum oxide in ethyl acetate gave the tetrahydro derivative as a 1 3 mixture of CIS- and rrd 5-decalin isomers. 

This dry ozonation procedure is a general method for hydrox-ylation of tertiary carbon atoms in saturated compounds (Table 1). The substitution reaction occurs with predominant retention of configuration. Thus cis-decalin gives the cis-l-decalol, whereas cis- and frans-l,4-dimethylcyclohexane afford cis- and trans-1,4-dimethylcyclohexanol, respectively. The amount of epimeric alcohol formed in these ozonation reactions is usually less than 1%. The tertiary alcohols may be further oxidized to diols by repeating the ozonation however, the yields in these reactions are poorer. For instance, 1-adamantanol is oxidized to 1,3-adamantane-diol in 43% yield. Secondary alcohols are converted to the corresponding ketone. This method has been employed for the hydroxylation of tertiary positions in saturated acetates and bromides. 

Other successful selective oxidations of hydrocarbons by Cr(VI) have been reported— for example, the oxidation of c/s-decalin to the corresponding alcohol—but careful attention to reaction conditions is required. 

Oxidation of trans-decalin leads to a mixture of 1- and 2-/ran.v-dccalonc.289... 

Oxidation rate constant k, for gas-phase second order rate constants, kOH for reaction with OH radical, kNQ3 with N03 radical and ko3 with 03 or as indicated, data at other temperatures see reference k0H = 1.96 x 10 1 cm3 molecule-1 s-1 of ds-decalin and 2.02 x 10 " cm3 molecule-1 s-1 of /oms-dccalin at... 

The effectiveness of the antioxidant depends not only on its reactivity, but also on its molecular weight that affects the rate of the antioxidant loss due to evaporation. The following example illustrates this dependence. Antioxidants of the structure 2,6-bis (1, l-dimethylethyl)phenols with para-substituents of the general structure ROCOCH2CH2 were introduced into decalin and polypropylene films that were oxidized by dioxygen at... 

Starting from quinic acid, a highly substituted, cis-afi unsaturated nitrile oxide has been synthesized and used in a 1,3-dipolar cycloaddition, to afford a precursor of the cis -decalin system of branimycin (468). 

Corey s retrosynthetic concept (Scheme 9) is based on two key transformations a cationic cyclization and an intramolecular Diels-Alder (IMDA) reaction. Thus, cationic cychzation of diene 50 would give a precursor 49 for epf-pseudo-pteroxazole (48), which could be converted into 49 via nitration and oxazole formation. Compound 50 would be obtained by deamination of compound 51 and subsequent Wittig chain elongation. A stereocontroUed IMDA reaction of quinone imide 52 would dehver the decaline core of 51. IMDA precursor 52 should be accessible by amide couphng of diene acid 54 and aminophenol 53 followed by oxidative generation of the quinone imide 52 [28]. 

Therefore, nine steps or synthetic operations are necessary in the conessine synthesis for isomerising the cir-B/C decalin system to trans-hIC, a transformation that in the cortisone synthesis is accomplished without any extra step, since it takes place spontaneously in the oxidation step, which, in turn, is necessary to introduce the second angular methyl group and build up ring D of cortisone in a stereoselective manner. Better correlation amongst different synthetic operations would be difficult to find in more recent synthesis of similar complexity and magnitude than that of Sarett. 

Smith and Burwell [61) showed that the reaction of deuterium with j9.io-octalin, which is catalyzed by reduced platinum oxide, yields a mixture of cis- and /mws-decalins containing an average of nearly three deuterium atoms per molecule. Under the same conditions J -octalin gave somewhat less of the cis isomer but the saturated products contained an average of two deuterium atoms per molecule. From a detailed analysis of the distribution of deuterium in the products they concluded that most of the cis- and all of the frans-decalin produced from... 

Depending on the catalysts, catalytic hydrogenation converts naphthalene to tetrahydronaphthalene (tetralin), or cis- or trons-decalin (decahydro-naphthalene) [S, 405, 406, 407]. Tetrahydronaphthalene was converted to ciy-decalin by hydrogenation over platinum oxide [S]. 

In regard to the stereoselectivity of the insertion process, Murray and coworkers have shown that the CH oxidation of substituted cyclohexanes by dioxiranes is, like the already discussed epoxidation, highly stereo-controUed . A specific case is c -decalin, which gives only the cis alcohol, as exemplarily displayed in equation 27. A similar stereoselective retention of configuration was also obtained for frawi-decalin and cis- and frawi-dimethylcyclohexanes"°. In fact, complete retention of configuration was demonstrated in the CH oxidation of chiral alkanes ". For example, the optically active (f )-2-phenylbutane was converted by either DMD or TFD" to (5 )-2-phenylbutan-2-ol (equation 28) without any loss of the enantiomeric purity (ep) in the product. 

Recently, substantial progress has been registered in regard to the regioselective CH oxidations by dioxiranes. Usually, the regioselectivity of the CH oxidation is mainly governed by the reactivity of the C—H bond for example, in the above-mentioned oxidation of c -decalin , the tertiary C—H bond is selectively oxidized in the presence of the secondary C—H bonds. When the reactivities are similar, the regioselectivity is determined by steric factors. For example, the preferential oxyfunctionalization of the tertiary C—H bond at the C-14 position of the steroid 19 by DMD in the presence of the other tertiary C—H bonds at the C-5, C-8 and C-9 positions is due to steric reasons (equation 30) . ... 

Intramolecular nitrile oxide-alkene cycloadditions also provide efficient access to six-membered rings such as cyclohexanes or decalins that are heavily adorned with functional groups and side chains. For example, this strategy was used to prepare racemic hemaldulcin (213), which is a 3,6-disubstituted cyclohexenone found in a Mexican plant that possesses a strong sweet taste. Starting from (2Z,6E)-famesal (209) (328) (Scheme 6.88), the aldehyde was treated with hydroxylamine... 

The intramolecular nitrile oxide-alkene cycloaddition has further been used for the construction of a tricyclic isoxazoline intermediate containing a decaline ring. 

Reactivity ratios for all the combinations of butadiene, styrene, Tetralin, and cumene give consistent sets of reactivities for these hydrocarbons in the approximate ratios 30 14 5.5 1 at 50°C. These ratios are nearly independent of the alkyl-peroxy radical involved. Co-oxidations of Tetralin-Decalin mixtures show that steric effects can affect relative reactivities of hydrocarbons by a factor up to 2. Polar effects of similar magnitude may arise when hydrocarbons are cooxidized with other organic compounds. Many of the previously published reactivity ratios appear to be subject to considerable experimental errors. Large abnormalities in oxidation rates of hydrocarbon mixtures are expected with only a few hydrocarbons in which reaction is confined to tertiary carbon-hydrogen bonds. Several measures of relative reactivities of hydrocarbons in oxidations are compared. 

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