Dimethyl solvolysis, oxidative

Hydrogen chloride dimethyl sulfoxide Oxidative solvolysis in dimethyl sulfoxide... 

A parallel was drawn between stable ion and AMI studies of methylphenanthrenes and solvolytic studies of K-region and non-K-region phenanthrene oxides. The carbocation formed by opening of the 1,2-epoxide closely resembled the 2-methylphenanthrene cation (and 7H ), and the regiochemistry of phenol formation (1-phenanthrol) could be understood. Similarly, phenanthrenium cations derived from the 3-methyl and dimethylated compounds served as models for carbo-cations formed by solvolysis of phenanthrene-3,4-epoxide (formation of 4-phenanthrol following hydride shift). 

Other reactions involving heterocycloalkane to heterocycloalkene transformations have met with quite limited success. Dehydrogenation reactions of saturated silacyclopentane derivatives with Pt/C or with an Al-Cr-K oxide catalyst yield complex mixtures of unsaturated cyclic products with one and two double bonds 140, 272), Dehydration or solvolysis reactions lead to ring cleavage [356) for instance, solvolysis of 4-tosyl-1,1-dimethyl-1-silacyclohexane affords low yields of 1,1-dimethyl-1-silacyclo hex-3-ene and several ring-opening products (356). 

By oxidation of the labeled products [28 and 29 or 30ab] to labeled benzoic and substituted benzoic acids followed by assay of these purified acids for carbon-14, the relative migratory abilities of the Ar groups with respect to phenyl were determined. Thus in the dehydration, with phosphorus pentoxide in xylene, of a series of carbinols (27, X = OH), the following migratory aptitudes (Ar Ph) were determined p-xenyl, 1-3 m-tolyl, 1-6 p-i-propylphenyl, l-8 3,4-dimethyl-phenyl, 1-9 p-tolyl, 2-0 p-ethylphenyl, 2-2 p-t-butylphenyl, 3-2 and p-anisyl, 21-2. Burr (1953) demonstrated the p-tolyl phenyl migration ratio to be 2-5 during the solvolysis of 2-phenyl-2- p-tolylethyl-l-i C tosylate (27, Ar = p-tolyl, X = tosyl). In a series of deaminations of the primary amines (27, X = NH ) and 31 (Ar = p-tolyl and o-tolyl) the p-tolyl phenyl (1 2), p-biphenyl phenyl (1 0) p-anisyl phenyl... 

Non-enolizable ketones can be easily cleaved with potassium tert-butoxide in dimethyl sulfoxide one of the newer powerful basic systems involving the widely applicable and versatile dimethyl sulfoxide, which has also been used for novel oxidative solvolysis reactions, e.g. the preparation of a-hydroxyamides from ketenimines... 

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