Reduction by complex hydrides

Nitrogen azoles are less easily reduced benzimidazole with lithium aluminum hydride gives 2,3-dihydrobenzimidazole (52CB390). 

Reduction of tetrazolo[ 1,5- ]pyridazine (274) by sodium borohydride results in the partial reduction of the pyridazine moiety (tetrahydro compound 275 was formed) (76JHC835). The catalytic reduction of the substituted tetrazolo[ 1,5- ]pyrimidine (276) afforded the diaminopyrimidine derivative (277) (85MIP155606). 

Two effective tin reagents, triethylammonium triphenyltin and dibuthyltin dihydride have been offered for reduction of fused tetrazoloazines to aminoazines (87TL5941). The reaction was interpreted to proceed via ring opening to an azide and subsequent reduction. 

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Figure 23 Reduction by complex hydrides of pyrazolones, thiopyrazolones, iminopyrazolines and pyrazolium salts...

Reduction by complex hydrides gives different results depending on the reagents and the conditions chosen. Unexpectedly, furotropone 383a yields dimer 383b [77BSF(2)75],... 

Boranes are generally less electron rich than corresponding aluminium analogues and electron transfer mechanisms are usually not considered for reduction reactions. However, an increase of the hydridic character in complex hydrides such as.LiBEt3H ( super hydride ) [68] or LiAlH4 [66] allows for the formation of well-characterized radical products in reactions with unsaturated acceptor heterocycles such as (3). Electron transfer mechanisms for the reduction by complex hydrides should be quite intricate because the coordinatively saturated donor moiety (MHn ) and the a acceptor part (e.g. Li" ) can now well separately interact with the coordinating n acceptor substrate. 

Reduction by complex hydrides Phosphorus nucleophiles Nucleophilic Attack at Hydrogen Attached to Ring Carbon or Ring Nitrogen... 

Reduction by complex hydrides Azide ions and nitrite ions Nucleophilic Attack at Hydrogen. 6.1 Metalation at a ring carbon atom... 

Halogermane reductions by complex hydrides are efficient, preferred methods for germane synthesis " . The complex hydrides used are MBH (M = Li, Na, K) and LiAlH.,. Reduction of Ge—X bonds by this method can be used for any molecule that otherwise is unsusceptible to complex hydride reduction or reaction. Lithium tetrahydroaluminate reduction of chiral halogermanes and alkoxygermanes results in inversion and retention of configuration, respectively. The LiBH., and LiAlH reactions require aprotic solvents, such as EtjO, THF, n-Bu O or glyme ethers. Sodium and K... 

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