Carbon tetrachloride/bromide reduction

Electrophilic addition to 9-vinylcarbazole occurs in the Markovnikov sense, thus hydrogen chloride,hydrogen bromide,chlorine, and bromine in carbon tetrachloride, and iodine chloride in pyridine are recorded as adding with initial electrophilic attack at the methylene. Mercuric acetate in methanol gave 9-(2-acetoxymercuri-l-methoxyethyl)carbazole. Although 9-vinylcarbazole gave an iodohydrin, comparable reaction with methanolic sodium hypochlorite led to 9-(2-chlorovinyl)carbazole. Catalytic reduction of the latter produced 9-(2-chloroethyl)carbazole. Tri-phenyltin hydride gave 96. ... 

A third approach to the preparation of allyl lluorovinyl ethers is the reaction of an allylic alcohol with trifluoroacetaldehyde, as illustrated by an alternative synthesis of 37a.17 Cinnamyl alcohol (47) forms with trifluoroacetaldehyde a hemiacetal, which is converted into bromide 48 via the mesy late. Reductive elimination affords 37a, which undergoes Claisen rearrangement within one hour in refluxing carbon tetrachloride to give 2,2-difluoro-3-phenylpent-4-enal (38a).17... 

Volatile protactinium pentaehloride has been prepared in a vacuum by reaction of the oxide with phosgene at 550° C or with carbon tetrachloride at 200°C. Reduction of this at 600°C with hydrogen leads to protactinium(IV) tetrachloride, Pad. which is isostructural with uranium(IV) tetrachloride, UCI4. The pentaehloride can be converted into the bromide or iodide by heating with the corresponding hydrogen halide or alkali halide... 

Under this heading a few borderline cases between direct and indirect electrochemical reactions can be included. Dihalocarbenes are probably intermediates in the cathodic reduction of certain polyhalogenated compounds172) as an example, cathodic reduction of carbon tetrachloride at a mercury cathode in acetonitrile-tetrabutylammonium bromide in the presence of tetramethylethylene gave a low yield of l,l-dichloro-2,2,3,3-tetramethylcyclopropane ... 

C HjJjCH- Prepd by ether reduction of triphenylchloro-methane obtained by reaction of carbon tetrachloride and benzene in the presence of aluminum chloride Norris, (by. Syn. 4, 81 (1925) from diphenyl chi oromethane and phenyl-magnesium bromide Say lea, Kharasch, J. Org, Chem. 26. 4210 (1961). 

A further patent for the production of codeine, via codeinone, from thebaine has been published. " Codeine has been shown to be oxidized by manganese dioxide to 14-hydroxycodeinone the reaction is presumed to proceed via codeinone since 6-acetylcodeine is not affected by the same reagent. 6-O-Methanesulphonyl-dihydrocodeine has been shown to react with tetra-butylammonium fluoride, lithium chloride, and lithium bromide, with inversion at C-6, to give the related 6-halogeno-dihydrocodides, but when the ester is heated with sodium iodide in dimethylformamide the product is A -deoxycodeine (deoxycodeine-C) (143). Reductive amination of naltrexone with 2,2 -dihy-droxydiethylamine and sodium cyanoborohydride yields the 6-amino-compound (144 R = OH), which can be converted by carbon tetrachloride and tri-... 

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