Magnesium activation

K2C03 CaH2, CaO or sodium, then fractionally distd. Near-dry alcohol can be further dried by refluxing with magnesium activated with iodine, as described for ethanol. Further purification is possible using fractional crystn, zone refining or preparative gas chromatography. 

Desulfonation.1 Magnesium, activated by 10 washes with dilute aqueous HC1 followed by 5 washes with distilled water, effects desulfonation in dry CH3OH at 50° in satisfactory yield. For example, phenyl p-phenethyl sulfone is converted into ethylbenzene in 68% yield. It is also useful for desulfonation of 1,1- and 1,2-disulfones. 

The purest available commercial propan-l-ol (propyl alcohol) should be dried with anhydrous potassium carbonate or with anhydrous calcium sulphate, and distilled through an efficient fractionating column. The fraction, b.p. 96.5-97.5 °C/760mmHg, is collected. If the propan-l-ol is required perfectly dry, it may be treated with magnesium activated with iodine by the method described above for ethanol. 

Barhier cyclization The Barbier reaction has been used for cyclopentenone annclation.5 Thus a-allylcycloalkanones are converted into the iodo ketones 1, which on treatment in THF with magnesium activated by HgCl2 are converted into bicycloalkanols (2) in moderate to good yield. Formation of cw-fused products is greatly favored. The reaction gives poor yields when extended to annelation of six-und scvcn-mcmbcred rings. 

Thompson JD, Nechay BR. 1981. Inhibition by metals of a canine renal calcium, magnesium activated adenosine triphosphatase. J Toxicol Environ Health 7 901-908. 

Two years after the first preparation of L-ribose, Fischer74 described the reduction of the sugar with sodium amalgam to the corresponding pentitol, which he showed to be identical with the polyol adonitol from Adonis vernalis L.75 76 A process for the catalytic hydrogenation of D-ribose in the presence of magnesium-activated Raney nickel to ribitol has been patented.77... 

Magnesium, activated by evfqmration or, much more conveniently, by sonication with anthracene (5%) usually accomplished the metallation of 2-alkenyl chlorides, e.g. (79) (81), at -65 C in THE... 

As summarized earlier, Oelkers (2001b) has proposed that the effect of dissolved cations derived from the dissolving silicate can be modeled using equations such as (25). For example, Oelkers and Schott (2001) reported that the rate of enstatite dissolution at pH 2 was independent of silica activity but decreased with increasing magnesium activity according to the following equation ... 

Ph), or phosphonic amides (97 R = NMe2 or MC HgO) with sodium in dioxane, or with magnesium activated by anthracene in THF, affords the bis(2-hydroxyaryl)phosphinic acid derivative (or phosphine oxide) (98) following a carbanionic rearrangement. 

The large value for the rate coefficient compared with those given in Table 10 raises the point as to whether it results from very high activity of catalytic sites, from a high proportion of active centres, or from a combination of both effects. The efficiency of the magnesium activated catalysts (obtained from Rpt/P vs. t) gives a value of / 0.5 [297]... 

In view of this uncertainty no definite conclusion can be drawn as to the activity of the sites in magnesium activated titanium catalysts. On balance it may be reasonably presumed that there is a positive effect, but doubts remain as to whether the earlier values are not underestimates by a considerable margin. 

Scattered reports have appeared in the literature of magnesium activation by stirring the solid under an inert atmosphere. The method is exemplified by the synthesis of the aromatic Grignard reagent shown in Figure 1. which frustrated attempts at its preparation by conventional techniques [4]. The development of this method has proved very effective in the synthesis of several allyl- and benzylmagnesium halides [5]. 

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