Chlorine, addition/reduction from

Chlorine, addition/reduction from diorganotellurides, 82 CID spectrometry... 

Erythramine (47), previously known as a reduction product of erythraline (4) (62), was detected in E. crysta galli and in E. glauca Willd. (now classified as E. fusca Loureiro) (19). Since there was insufficient sample isolated, erythramine was prepared from erythraline and its structure established by NMR. In addition, erythramine was prepared by an alternative route from erythratine (42) (see Scheme 8) by chlorination and reduction. Since 42 could also be converted to erythraline (79), an alkaloid of known stereochemistry (63), the position of the double bond as well as the configurations at C-3 and C-5 in erythramine were firmly established. 

Reports from Kuhn and co-workers identified the reaction of stable car-benes with 1,2-dichloroethane to yield 2-chloro-l,3-disubstituted imidazo-lium chloride salts.58 The versatility of these salts has been demonstrated by Ishikawa and co-workers.59 Due to its strong electrophilicity, 2-chloro-l, 3-dimethylimidazolium chloride can be used in chlorination, oxidation, reduction and rearrangement reactions, in addition to being used as a dehydrating agent. 

The electron affinities of halogenated aromatic and aliphatic compounds and nitro compounds have been evaluated. Additional electron affinities for halogenated benzene, freons, heterocyclic compounds, dibenzofuran, and the chloro- and fluoroben-zenes are reported from ECD data. The first positive Ea for the fluorochloroethanes were obtained from published ECD data. The Ea of halogenated aromatic radicals have been estimated from NIMS data. The AEa of all the halobenzenes have been calculated using CURES-EC. The Ea of chlorinated biphenyls and chlorinated napthalenes obtained from reduction potentials have been revised based on variable solution energy differences. 

Removing the chlorine an additional atom from the pyridazine ring as in 19 eliminates activity, and the use of leaving groups or hydrolyzable groups for the chlorine (20-28) also caused a marked reduction in activity. 

Dichloroacetic acid is produced in the laboratory by the reaction of chloral hydrate [302-17-0] with sodium cyanide (31). It has been manufactured by the chlorination of acetic and chloroacetic acids (32), reduction of trichloroacetic acid (33), hydrolysis of pentachloroethane [76-01-7] (34), and hydrolysis of dichloroacetyl chloride. Due to similar boiling points, the separation of dichloroacetic acid from chloroacetic acid is not practical by conventional distillation. However, this separation has been accompHshed by the addition of a eotropeforming hydrocarbons such as bromoben2ene (35) or by distillation of the methyl or ethyl ester. 

The properties of chlorine azide resemble those of bromine azide. Pon-sold has taken advantage of the stronger carbon-chlorine bond, i.e., the resistance to elimination, in the chloro azide adducts and thus synthesized several steroidal aziridines. 5a-Chloro-6 -azidocholestan-3 -ol (101) can be converted into 5, 6 -iminocholestan-3l -ol (102) in almost quantitative yield with lithium aluminum hydride. It is noteworthy that this aziridine cannot be synthesized by the more general mesyloxyazide route. Addition of chlorine azide to testosterone followed by acetylation gives both a cis- and a trans-2iddMct from which 4/S-chloro-17/S-hydroxy-5a-azidoandrostan-3-one acetate (104) is obtained by fractional crystallization. In this case, sodium borohydride is used for the stereoselective reduction of the 3-ketone... 

Chlorination and fluorination, as processes of metal extraction, are important not only because they are effective in liberating metal values from refractory ores but also because the chlorides and the fluorides are excellent interprocess intermediates for metal reduction. The chlorides have the additional advantage of being compounds which may be made very pure by certain additional processes. 

Reaction rate constants are postulated as shown in Table II for degradation in water (biolysis and photolysis), in bottom sediments (probably biolysis), and for permanent burial of sediment. The values were selected from a perusal of the literature and must be regarded as speculative. A factor of 20 reduction in reaction rate constant is assumed for addition of each chlorine. 

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