Complex hydrides amide

This comprises both new catalysts and new alloys. Here, new fundamental knowledge is needed in order to fully understand the catalyst mechanism and, more importantly, hydride destabilization. Further discussions on some new directions are the subject of other chapters of this book (complex hydrides, amides, destabilized systems, aluminum hydride, nanoparticles and theoretical modeling). 

HYTRA1N University of Salford, UK 48 since 01/01/2005 Mg-baaed, complex hydrides e.g. a la nates, borohyd rides), novel light hydrides (Li nitrides, amides) 2.65... 

Reduction of amides to aldehydes was accomplished mainly by complex hydrides. Not every amide is suitable for reduction to aldehyde. Good yields were obtained only with some tertiary amides and lithium aluminum hydride, lithium triethoxyaluminohydride or sodium bis 2-methoxyethoxy)aluminum hydride. The nature of the substituents on nitrogen plays a key role. Amides derived from aromatic amines such as JV-methylaniline [1103] and especially pyrrole, indole and carbazole were found most suitable for the preparation of aldehydes. By adding 0.25 mol of lithium aluminum hydride in ether to 1 mol of the amide in ethereal solution cooled to —10° to —15°, 37-60% yields of benzaldehyde were obtained from the benzoyl derivatives of the above heterocycles [1104] and 68% yield from N-methylbenzanilide [1103]. Similarly 4,4,4-trifluorobutanol was prepared in 83% yield by reduction of N-(4,4,4-trifluorobutanoyl)carbazole in ether at —10° [1105]. 

The predominant application of reduction of amides lies in their conversion to amines, realized most often by hydrides and complex hydrides. Primary,... 

Complex metal hydroborates and hydroaluminates, hydridoferrates and modified complex hydrides (e.g., NaBH -AlClj) reduce organic N-containing compounds " (see also 1.5.5.1), e.g., amides ... 

There are several ways to cleave the auxiliary from the product 7. Typical reactions include reduction with complex hydrides such as LiBH4 to obtain the alcohol 18 or transamination to the Weinreb amide and subsequent reduction with DIBAL to give the aldehyde 19 that would have been obtained from direct aldol reaction. ... 

A new complex hydride system based on lithium amide has been developed. For this system, the following reversible displacement reaction takes place at 285°C and 1 atm ... 

Two novel complex hydrides are likely to find applications in steroid chemistry lithium perhydro-9b-boraphen yl hydride affords unusually high proportions of axial alcohols in model compounds sodium bis(methoxyethoxy)aluminium dihydride, Na (MeOCH2CH20)JAlH2, a very safe and convenient substitute for lithium aluminium hydride, readily reduces not only ketones but also acids, nitro-compounds, oximes, amides, lactones, etc. An improved procedure for Clemmensen reduction of steroid ketones involves saturating an ethereal solution with hydrogen chloride while stirring with zinc. 5a-Cholestane was obtained from the 3-one in 89% yield. ... 

This chapter summarizes important contributions on the AB5/AB and elemental hydrides. Examples of microalloying in LaNis- and FeTi-based intermetallic hydrides have been emphasized, and there has been some discussion on elemental hydrides. Classification of testing methods for durability of alloys/ intermetallics were presented, examples of intrinsic and extrinsic tests that include cycling and aging have been reported for AB5/AB and other alloys. More recent results on extrinsic tests on lightweight complex hydrides (imide-amide) that were cycled between Li2NH/LiNH2 phases were also reported. 

Some of the highest storage capacities are for complex hydrides and because of this there has been considerable research on alanates, borohydrides and amides/imides. One of the most successful systems (in terms of reversibility) has been that of sodium alanate, although the cyclable capacity is low at... 

Amides of amino acids react with complex hydrides resulting in reduction of the carbonyl to a methylene group. Thus, it is possible to obtain a variety of diamines (not containing a-hy-droxy groups) in ail enantionierically pure form. The amino acids generally employed are phcnylglycine1 and proline2 3. The majority of amines discussed in this section were used as the lithium salt in enantioselective deprotonation and elimination (Section C.). 

The products are versatile auxiliaries not only for enantioselective deprotonation and elimination (Section C.), but are also valuable chiral ligands for complex hydrides in the enantioselective reduction of ketones (Section D.1.4.5.)- They are also applied in enolate reactions (Section D.l.5.2.1., D.1.5.2.4.). transition-metal-catalyzed Michael additions (Section D.l.5.8.), 1,3-dipolar cycloadditions (Section D.l.6.1.2.1.), and additions ofGrignard reagents (Section D.l.3.1.4.2.5.). (5 )-2-(Phenylaminomethyl)pyrrolidine has found most application and is also commercially available. Several methods exist for the preparation of such compounds. Two typical procedures for the synthesis of (.S)-2-(l-pyrrolidinylmcthyl)pyrrolidine are presented here. The methodology can be readily extended to other amides and alkylamino derivatives of proline. 

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