Lithium-Aluminum System

Because of the interest in its use in elevated-temperature molten salt electrolyte batteries, one of the first binary alloy systems studied in detail was the 

In addition to this work on the fi phase, both the thermodynamic and kinetic properties of the terminal solid-solution region, which extends to about 9 atom% lithium at 423 °C, were also investigated in detail [43]. 

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Hydroisoquinolines. In addition to the ring-closure reactions previously cited, a variety of reduction methods are available for the synthesis of these important ring systems. Lithium aluminum hydride or sodium in Hquid ammonia convert isoquinoline to 1,2-dihydroisoquinoline (175). Further reduction of this intermediate or reduction of isoquinoline with tin and hydrochloric acid, sodium and alcohol, or catalyticaHy using platinum produces... 

Lithium—Aluminum/Metal Sulfide Batteries. The use of high temperature lithium ceUs for electric vehicle appUcations has been under development since the 1970s. Advances in the development of lithium aUoy—metal sulfide batteries have led to the Li—Al/FeS system, where the foUowing ceU reaction occurs. 

Among ring-fused systems, the 3-(o-aminoaryl)benzisoxazole (506) underwent rearrangement on refluxing in THF with sodium hydride or lithium aluminum hydride. In this case the 3-(o-hydroxyphenyl)benzimidazole (506a) was obtained. 

A direct reduction of the A" -3-keto system can be effected with lithium aluminum hydride-aluminum chloride. The last two methods are unsatisfactory with A -3-ketones (ref. 185, p. 253 ref. 255, but cf. ref. 229). 

Enamines of A" -3-ketones (45) are stable to lithium aluminum hydride, but lithium borohydride reduces the 3,4-double bond of the enamine system." In the presence of acetic acid the enamine (45) is reduced by sodium borohydride to the A -3-amine (47) via the iminium cation (46). ... 

Iodine azide, on the other hand, forms pure adducts with A -, A - and A -steroids by a mechanism analogous to that proposed for iodine isocyanate additions. Reduction of such adducts can lead to aziridines. However, most reducing agents effect elimination of the elements of iodine azide from the /mwj -diaxial adducts of the A - and A -olefins rather than reduction of the azide function to the iodo amine. Thus, this sequence appears to be of little value for the synthesis of A-, B- or C-ring aziridines. It is worthy to note that based on experience with nonsteroidal systems the application of electrophilic reducing agents such as diborane or lithium aluminum hydride-aluminum chloride may yet prove effective for the desired reduction. Lithium aluminum hydride accomplishes aziridine formation from the A -adducts, Le., 16 -azido-17a-iodoandrostanes (97) in a one-step reaction. The scope of this addition has been considerably enhanced by the recent... 

Thus the critical synthetic 1,6-dihydropyridine precursor for the unique isoquinuclidine system of the iboga alkaloids, was generated by reduction of a pyridinium salt with sodium borohydride in base (137-140). Lithium aluminum hydride reduction of phenylisoquinolinium and indole-3-ethylisoquinolinium salts gave enamines, which could be cyclized to the skeletons found in norcoralydine (141) and the yohimbane-type alkaloids (142,143). 

Besides the two battery systems, a third high temperature system has been under development for a long time lithium aluminum iron sulfide (LiAl/FeS2) [1], This... 

Some bis(salicylaldehydo) complexes of cobalt(II), nickel(II), and cop-per(II), with or without lithium aluminum hydride, are said to catalyze hydrogenation of benzene and alkylbenzenes at 200°C, but the systems appear to be heterogeneous (447). 

The utilization of the Robinson annellation method for the synthesis of cory-nanthe-type alkaloids has been thoroughly investigated by Kametani and coworkers (149-152). The tetracyclic ring system was efficiently formed via the Michael addition of dimethyl 3-methoxyallylidenemalonate (247) to the enamine derived from 3,4-dihydro-1 -methyl-(3-carboline (150). Alkylation of 248, followed by hydrolysis and decarboxylation, resulted in a mixture of stereosiomeric enamides 250 and 251. Hydrogenation of 250 afforded two lactams in a ratio of 2 1 in favor of the pseudo stereoisomer 253 over the normal isomer 252. On the other hand, catalytic reduction of 251 gave 254 as the sole product in nearly quantitative yield. Deprotection of 254, followed by lithium aluminum hydride reduction, yielded ( )-corynantheidol (255) with alio relative configuration of stereo centers at C-3, C-15 and C-20. Similar transformations of 252 and 253 lead to ( )-dihydrocorynantheol and ( )-hirsutinol (238), respectively, from which the latter is identical with ( )-3-epidihydrocorynantheol (149-151.). 

D-Ribonolactone is a convenient source of chiral cyclopentenones, acyclic structures, and oxacyclic systems, useful intermediates for the synthesis of biologically important molecules. Cyclopentenones derived from ribono-lactone have been employed for the synthesis of prostanoids and carbocyclic nucleosides. The cyclopentenone 280 was synthesized (265) from 2,3-0-cyclohexylidene-D-ribono-1,4-lactone (16b) by a threestep synthesis that involves successive periodate oxidation, glycosylation of the lactol with 2-propanol to give 279, and treatment of 279 with lithium dimethyl methyl-phosphonate. The enantiomer of 280 was prepared from D-mannose by converting it to the corresponding lactone, which was selectively protected at HO-2, HO-3 by acetalization. Likewise, the isopropylidene derivative 282 was obtained (266) via the intermediate unsaturated lactone 281, prepared from 16a. Reduction of 281 with di-tert-butoxy lithium aluminum hydride, followed by mesylation, gave 282. 

A list of oxides in these terms is presented as Table 9.6. Following the logic described, one obtains an exothermic system by choosing a metal whose oxide has a -AH per oxygen atom high on the list to react with a metal oxide that is lower on the list. Indeed, the application of this conceptual approach appears to explain why in the oxidation of lithium-aluminum alloys, the dominant product is Li20 and that A1 does not bum in the vapor phase [9],... 

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