Sodium aluminum hydride dehydrogenation

J. Wang, A.D. Ebner, R. Zidan, J.A. Ritter, Synergistic effects of co-dopants on the dehydrogenation kinetics of sodium aluminum hydride , J. Alloys Compd. 391 (2005) 245-255. 

When the sodium atom in sodium aluminum hydride is replaced with a lithium atom, it is found that lithium aluminum hydride readily dehydrogenates, with faster kinetics and at lower temperatures than the sodium species [48, 49]. One might conclude that the decompositimi is related to the aluminum component of the anion, especially because structural analysis of the decompositions shows that there is a stable intermediate of AlHs in both the lithium and sodium cases. The faster kinetics and lower decomposition temperature are also expected, as lithium hydride is substantially more stable that sodium hydride, with stability measured by the heat of formation of each molecule [50]. 

Reduction of the 1//-1,2-benzodiazepines 6 with lithium aluminum hydride results in the dihydro compounds 8, which are dehydrogenated to the 3H-1,2-benzodiazepines 9 by 4-phenyl-4//-l,2,4-triazole-3,5-dione.123 The products readily revert to the 1//-tautomers in the presence of sodium methoxide. 3//-1,2-Benzodiazepines react with 3-chloroperoxybenzoic acid to give mixtures of 1- and 2-oxides, 10 and 11, in which the latter predominate. Treatment of the 2-oxides 11 with nucleophiles provides 3-substituted H- 1.2-benzodiazepines 12. Selected examples are given.124... 

The apparently simple procedures of partial dehydrogenation of pyrrolidines and partial hydrogenation of pyrroles afford Zl1-pyr-rolines. However, the reaction is complex and is of little preparative value.97-98 A 1-Pyrrolines may be obtained by isomerization of A 3-pyrrolines.100 From the preparative point of view, partial hydrogenation of quaternary pyridine salts in strongly alkaline media to give 1-alkyl-id 2-piperideines is more important.101 Formation of heterocyclic enamines was observed in the reduction of i -methyl-pyrrolidone with lithium aluminum hydride,102 -alkylpiperidones with sodium in ethanol,103,104 and in the electrolytic reduction of N-methylglutarimide.106... 

Dehydrogenation of equilins to equilenins The equilin derivative (1) is dehydrogenated to the equilenin derivative (2) when refluxed in toluene with sodium bis-(2-methoxyethoxy)aluminum hydride. If lithium aluminum hydride... 

DEHYDROGENATION t-Butyl hypochlorite. 2,3-Dichloro-5,6-dicyanobenzoquinone. Pyridine. Pyridinium hydrobromide. Sodium bis-(2-methoxyethoxy)aluminum hydride. Sulfur. Trityl tetrafluoroborate. Trityl trifluoroacetate. 

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