Reductions with Magnesium

Fig. 4. Flow sheet for the processing of titanium ore by chlorination followed by reduction with magnesium.

Rubidium metal may be obtained from its carbonate, hydroxide or chloride by reduction with magnesium or calcium at high temperatures in the presence of hydrogen ... 

Zirconium metal is produced from its tetrachloride by reduction with magnesium by the Kroll process. The oxide obtained above is converted to zirconium tetrachloride by heating with carbon and chlorine. In practice, the oxide is mixed with lampblack, powdered sugar, and a little water, and pelletized. The dried pellet is then heated with chlorine in a chlorinator to produce ziro-conium tetrachloride ... 

Indole-2-carboxylic esters undergo reduction with magnesium in methanol to give the related indoline (86TL2409). 

The metal can be isolated by ignition of the tartrate, the carbon liberated by the decomposition of the tartaric acid radical reducing the carbonate simultaneously formed from the chloride by electrolysis in the fused state,7 or by the action of calcium8 and from the hydroxide by electrolysis,9 or by reduction with magnesium.10... 

The popularity of the Nef reaction is due in part to the ready availability of nitro compounds. Primary and secondary halides react with sodium nitrite in dimeAyl sulfoxide (DMSO) or dimethylform-amide (DMF) to give useful yields of nitro compounds. Primary amines can be oxidized to nitro compounds with potassium permanganate, m-chloroperbenzoic acitP or ozone. Chlorination of oximes with hypochlorous acid and reduction with magnesium, zinc or hydrogen/lpalladium gives secondary nitro compounds. Stabilized carbanions can be nitrated by treauitent with a nitrate ester, and enol acetates are nitrated by acetyl nitrate to give nitro ketones. ... 

Perfluorinated ketones form stable hydrates, (Rp)2C(OH)2, and these diols are very acidic. Hexafluoroacetone hydrate is known to be a very good solvent and is particularly useful for certain polymers [112, 152]. Perfluoropinacol may be obtained from hexafluoroacetone by photolytic reduction (Figure 8.44), whilst classical reduction with magnesium amalgam gives only low yields [112]. The same pinacol is also obtained by heating 8.44A, which is produced as shown in Figure 8.44 [153]. 

Hydroxy ketones of the type RCOCHjCHOHCHj are formed in 35-66% yields by partial catalytic hydrogenation of the corresponding /S-diketones over Raney nickel at KX) . Aromatic a-hydroxy ketones (benzoins) are prepared from the corresponding a-diketones (benzils) by catalytic reduction or by reduction with magnesium-magnesium iodide mixture. ... 

Use Production of beryllium metal by reduction with magnesium metal nuclear reactors glass manufacturing. 

Compounds carrying a trifluoroacetyl group, for example trifluoromethyl ketones and esters of trifluoroacetic acid, can be converted into the corresponding trimethylsilyl difluoroenol ethers [27] or into trimethylsilyldifluoroacetic acid esters [28] by reduction with magnesium metal in the presence of Me SiCl (Scheme 2.195). These readily accessible species are synthetically very useful as nucleophilic difluoromethylene equivalents. The same type of chemistry [29] can also be extended to trifluoromethyl imines [30]. 

Pig. 10. Asymmetric reduction with magnesium alkoxides (a) from Streitwieser and Wolfe (1957) (6) from Belleau and Burba (1960). 

The reduction of porous silica with magnesium vapor is a highly exothermic reaction. The process with thermal moderators is an attractive route to generating highly mesoporous silicon (surface areas >500 m /g). Without thermal moderators, large batches of macroporous silicon can be generated by combustion synthesis. Electrochemical reduction with molten calcium or lithium salts rather than thermal reduction with magnesium is also under evaluation. The use of liquid aluminum to reduce mesoporous silica deserves much further study. 

The first carbene-stabilized phosphorus mononitride was also synthesized using CAAC A [222], Reaction of SIPr=N-PCl2 with CAAC A, followed by reduction with magnesium metal, afforded the phosphorus mononitride adduct stabilized by one SIPr NHC and one CAAC A (Figure 15.54). This molecule features a P-N distance of 1.7085(16) A as measured by X-ray crystallography. Oxidation using trityl tetrakis(pentafluorophenyl)borate gave the radical cation as a dark-brown-colored microcrystalline solid. EPR spectroscopy in fluorobenzene... 

Titanium was first produced by the Hunter process [6] but this has been superseded, except for special applications, by the Kroll process [4, 6] which entails the carbochlorination of rutile and ilmenite to obtain titanium tetrachloride, followed by metallothermic reduction with magnesium. 

In 1989, Mullen et al. reported the first example of 2,8 4,6-biannulated SBV (Scheme 4.10) [38]. Starting from tetraester 4-14, after four steps the tetrabromo compound 4-15 was synthesized. Further, four steps in synthesis constructed the biannulated tetracyclic skeleton. Finally, reduction with magnesium gave biannu-lated SBV 4-16. Line broadening of solution-phase NMR of 4-16 at —160 °C was not observed. At this temperature, the upper limit of activation barrier of Cope rearrangement was determined as 3.6 kcal/mol, which is lower than the value 5.5 kcal/mol of unsubstituted SBV. 

The text mentions that scandium metal is obtained from its molten chloride by electrolysis, and that titanium is obtained from its chloride by reduction with magnesium. Why are these metals not obtained by the reduction of their oxides with carbon (coke), as are metals such as zinc and iron ... 

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