Reduction of organic compounds with sodium borohydride-transition metal salt systems

A Generic Approach for the Catalytic Reduction of Nitriles.

“…4,29 In some cases, however, when cobalt salts were employed no reduction of the double bond occurred. 13 As documented in the literature 4,30 a ketone was found to be reduced to the corresponding secondary alcohol (entry 28) in the presence of a boride species and excess borohydride. Pyridine derivatives display at worst moderate yields (entries 12 and 24), consistent with the lower yields reported for these species.…”

“…Pyridine derivatives display at worst moderate yields (entries 12 and 24), consistent with the lower yields reported for these species. 13,14 Other heterocycles do not appear to be affected by this reaction (entries 16, 17, and 22). 12 Neither hydroxyl groups nor amines interfere with the reaction (entries 16 and 26), merely Boc protection may occur (entry 9).…”

“…In order to isolate primary amines treatment with acetic anhydride or di-tert-butyl dicarbonate in a one-pot reaction was required to prevent dimerisation, a well known side reaction that can occur during the reduction of nitriles unless the reaction conditions are carefully adjusted. 9,13,19,21,22 This method of trapping the primary amine is analogous to that employed in the hydrogenation of nitriles. 23 It should be noted that Khurana et al 24 have recently reported the reduction of nitriles to primary amines with little or no secondary amine detected by changing to anhydrous conditions and performing the reduction with stoichiometric amounts of nickel(II) chloride, using a limited amount of sodium borohydride in ethanol.…”

“…These yields are not surprising, especially since the cobalt boride mediated method has been shown to cleanly reduce this functionality to amines. 13 Although this improved method for the reduction of the cyano group is reliable and tolerates some functional groups, small changes to the procedure and/or a change in metal boride can lead to a total change in reducing ability and selectivity. 13,14 Further to these results in a few cases slight modification of the reaction procedure was found to improve yields dramatically.…”

Water Extract of Piper Nigrum Seed Assisted Synthesis of Silver Nanoparticles and Reduction of Various Nitro Compounds by NaBH4 in the Presence of AgNPs as a Catalyst

“…This is a well known fact that alone NaBH 4 does not reduce nitro compounds. However, when the same reagent is combined with transition metal halides or their salts such as NaBH 4 /CoCl 2 , NaBH 4 /FeCl 2 , NaBH 4 /CuSO 4 etc., [14][15][16][17] can reduce the nitro compounds in to the corresponding amines. Further we wish to report for the first time reduction of various nitro compounds to corresponding amines by NaBH 4 in the presence of AgNPs as a catalyst.…”