Amines Sodium borohydride-Nickel boride

REDUCTION, REAGENTS Bis(N-methylpi-perazinyl)aluminum hydride. Borane-Di-methyl sulfide. Borane-Tetrahydrofurane. Borane-Pyridine. n-Butyllithium-Diisobu-tylaluminum hydride. Calcium-Amines. Diisobutylaluminum hydride. 8-Hydroxy-quinolinedihydroboronite. Lithium aluminum hydride. Lithium 9-boratabicy-clo[3.3.1]nonane. Lithium n-butyldiisopro-pylaluminum hydride. Lithium tri-j c-butylborohydride. Lithium triethylborohy-dride. Monochloroalane. Nickel boride. 2-Phenylbenzothiazoline. Potassium 9-(2,3-dimethyl-2-butoxy)-9-boratabicy-clo[3.3.1]nonane. Raney nickel. Sodium bis(2-methoxyethoxy)aluminum hydride. Sodium borohydride. Sodium borohy-dride-Nickel chloride. Sodium borohy-dride-Praeseodymium chloride. So-dium(dimethylamino)borohydride. Sodium hydrogen telluride. Thexyl chloroborane-Dimethyl sulfide. Tri-n-butylphosphine-Diphenyl disulfide. Tri-n-butyltin hydride. Zinc-l,2-Dibromoethane. Zinc borohydride. 

Titanium(II) reagents have also been used to reduce aliphatic nitro compounds to amines halo, cyano and ester groups are not reduced. Sodium borohydride, in the presence of catalytic amounts of nickel(II) chloride, reduces a variety of aliphatic nitro compounds to amines. Nickel boride (Ni2B) is an active catalyst for reductions of primary, secondary and tertiary nitro aliphatic compounds to amines. The reduction of nitrocyclohexane (45) yields cyclohexylamine (47) as well as small amounts of dicyclohexylamine (49), the latter being formed via reaction of intermediates (46) and (48 equation 28). 

Procedures were proposed for the reduction of aromatic nitro groups to amines. Sodium dithionitei78 and a combination of sulfur and hydrazine on activated carboni79 are reported to provide anilines in good to excellent yields. From aliphatic nitro compounds (Eq. 66), primary amines could be obtained with "nickel boride", prepared from nickel chloride and sodium borohydride.i ... 

The reaction between 2-nitrothiophen and secondary aliphatic amines leads most probably to the ring-opened product (213). Raney-Nickel desulphurization continues to play an important role in the structure determination of thiophen derivatives, and for the synthesis of macrocyc-lic compounds, such as a-alkylcycloalkanones, amino-lactams of aliphatic diaminocarboxylic acids, and of dethiobiotin. The nickel boride catalyst (NiBo), prepared from nickel(ii) chloride and sodium borohydride in methanol, gives olefins in 50—55% yield. From (214) a mixture of methyl... 

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